diff options
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/Makefile | 9 | ||||
| -rw-r--r-- | drivers/tty/n_gsm.c | 2763 | ||||
| -rw-r--r-- | drivers/tty/n_hdlc.c | 1007 | ||||
| -rw-r--r-- | drivers/tty/n_r3964.c | 1264 | ||||
| -rw-r--r-- | drivers/tty/n_tty.c | 2121 | ||||
| -rw-r--r-- | drivers/tty/pty.c | 777 | ||||
| -rw-r--r-- | drivers/tty/sysrq.c | 811 | ||||
| -rw-r--r-- | drivers/tty/tty_audit.c | 358 | ||||
| -rw-r--r-- | drivers/tty/tty_buffer.c | 524 | ||||
| -rw-r--r-- | drivers/tty/tty_io.c | 3263 | ||||
| -rw-r--r-- | drivers/tty/tty_ioctl.c | 1179 | ||||
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 915 | ||||
| -rw-r--r-- | drivers/tty/tty_mutex.c | 47 | ||||
| -rw-r--r-- | drivers/tty/tty_port.c | 446 |
14 files changed, 15484 insertions, 0 deletions
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile new file mode 100644 index 00000000000..7f63b3315e8 --- /dev/null +++ b/drivers/tty/Makefile @@ -0,0 +1,9 @@ +obj-y += tty_io.o n_tty.o tty_ioctl.o tty_ldisc.o \ + tty_buffer.o tty_port.o tty_mutex.o +obj-$(CONFIG_LEGACY_PTYS) += pty.o +obj-$(CONFIG_UNIX98_PTYS) += pty.o +obj-$(CONFIG_AUDIT) += tty_audit.o +obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o +obj-$(CONFIG_N_HDLC) += n_hdlc.o +obj-$(CONFIG_N_GSM) += n_gsm.o +obj-$(CONFIG_R3964) += n_r3964.o diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c new file mode 100644 index 00000000000..04ef3ef0a42 --- /dev/null +++ b/drivers/tty/n_gsm.c @@ -0,0 +1,2763 @@ +/* + * n_gsm.c GSM 0710 tty multiplexor + * Copyright (c) 2009/10 Intel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * + * + * TO DO: + * Mostly done: ioctls for setting modes/timing + * Partly done: hooks so you can pull off frames to non tty devs + * Restart DLCI 0 when it closes ? + * Test basic encoding + * Improve the tx engine + * Resolve tx side locking by adding a queue_head and routing + * all control traffic via it + * General tidy/document + * Review the locking/move to refcounts more (mux now moved to an + * alloc/free model ready) + * Use newest tty open/close port helpers and install hooks + * What to do about power functions ? + * Termios setting and negotiation + * Do we need a 'which mux are you' ioctl to correlate mux and tty sets + * + */ + +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/ctype.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/bitops.h> +#include <linux/file.h> +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/timer.h> +#include <linux/tty_flip.h> +#include <linux/tty_driver.h> +#include <linux/serial.h> +#include <linux/kfifo.h> +#include <linux/skbuff.h> +#include <linux/gsmmux.h> + +static int debug; +module_param(debug, int, 0600); + +#define T1 (HZ/10) +#define T2 (HZ/3) +#define N2 3 + +/* Use long timers for testing at low speed with debug on */ +#ifdef DEBUG_TIMING +#define T1 HZ +#define T2 (2 * HZ) +#endif + +/* Semi-arbitary buffer size limits. 0710 is normally run with 32-64 byte + limits so this is plenty */ +#define MAX_MRU 512 +#define MAX_MTU 512 + +/* + * Each block of data we have queued to go out is in the form of + * a gsm_msg which holds everything we need in a link layer independant + * format + */ + +struct gsm_msg { + struct gsm_msg *next; + u8 addr; /* DLCI address + flags */ + u8 ctrl; /* Control byte + flags */ + unsigned int len; /* Length of data block (can be zero) */ + unsigned char *data; /* Points into buffer but not at the start */ + unsigned char buffer[0]; +}; + +/* + * Each active data link has a gsm_dlci structure associated which ties + * the link layer to an optional tty (if the tty side is open). To avoid + * complexity right now these are only ever freed up when the mux is + * shut down. + * + * At the moment we don't free DLCI objects until the mux is torn down + * this avoid object life time issues but might be worth review later. + */ + +struct gsm_dlci { + struct gsm_mux *gsm; + int addr; + int state; +#define DLCI_CLOSED 0 +#define DLCI_OPENING 1 /* Sending SABM not seen UA */ +#define DLCI_OPEN 2 /* SABM/UA complete */ +#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ + + /* Link layer */ + spinlock_t lock; /* Protects the internal state */ + struct timer_list t1; /* Retransmit timer for SABM and UA */ + int retries; + /* Uplink tty if active */ + struct tty_port port; /* The tty bound to this DLCI if there is one */ + struct kfifo *fifo; /* Queue fifo for the DLCI */ + struct kfifo _fifo; /* For new fifo API porting only */ + int adaption; /* Adaption layer in use */ + u32 modem_rx; /* Our incoming virtual modem lines */ + u32 modem_tx; /* Our outgoing modem lines */ + int dead; /* Refuse re-open */ + /* Flow control */ + int throttled; /* Private copy of throttle state */ + int constipated; /* Throttle status for outgoing */ + /* Packetised I/O */ + struct sk_buff *skb; /* Frame being sent */ + struct sk_buff_head skb_list; /* Queued frames */ + /* Data handling callback */ + void (*data)(struct gsm_dlci *dlci, u8 *data, int len); +}; + +/* DLCI 0, 62/63 are special or reseved see gsmtty_open */ + +#define NUM_DLCI 64 + +/* + * DLCI 0 is used to pass control blocks out of band of the data + * flow (and with a higher link priority). One command can be outstanding + * at a time and we use this structure to manage them. They are created + * and destroyed by the user context, and updated by the receive paths + * and timers + */ + +struct gsm_control { + u8 cmd; /* Command we are issuing */ + u8 *data; /* Data for the command in case we retransmit */ + int len; /* Length of block for retransmission */ + int done; /* Done flag */ + int error; /* Error if any */ +}; + +/* + * Each GSM mux we have is represented by this structure. If we are + * operating as an ldisc then we use this structure as our ldisc + * state. We need to sort out lifetimes and locking with respect + * to the gsm mux array. For now we don't free DLCI objects that + * have been instantiated until the mux itself is terminated. + * + * To consider further: tty open versus mux shutdown. + */ + +struct gsm_mux { + struct tty_struct *tty; /* The tty our ldisc is bound to */ + spinlock_t lock; + + /* Events on the GSM channel */ + wait_queue_head_t event; + + /* Bits for GSM mode decoding */ + + /* Framing Layer */ + unsigned char *buf; + int state; +#define GSM_SEARCH 0 +#define GSM_START 1 +#define GSM_ADDRESS 2 +#define GSM_CONTROL 3 +#define GSM_LEN 4 +#define GSM_DATA 5 +#define GSM_FCS 6 +#define GSM_OVERRUN 7 + unsigned int len; + unsigned int address; + unsigned int count; + int escape; + int encoding; + u8 control; + u8 fcs; + u8 *txframe; /* TX framing buffer */ + + /* Methods for the receiver side */ + void (*receive)(struct gsm_mux *gsm, u8 ch); + void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); + /* And transmit side */ + int (*output)(struct gsm_mux *mux, u8 *data, int len); + + /* Link Layer */ + unsigned int mru; + unsigned int mtu; + int initiator; /* Did we initiate connection */ + int dead; /* Has the mux been shut down */ + struct gsm_dlci *dlci[NUM_DLCI]; + int constipated; /* Asked by remote to shut up */ + + spinlock_t tx_lock; + unsigned int tx_bytes; /* TX data outstanding */ +#define TX_THRESH_HI 8192 +#define TX_THRESH_LO 2048 + struct gsm_msg *tx_head; /* Pending data packets */ + struct gsm_msg *tx_tail; + + /* Control messages */ + struct timer_list t2_timer; /* Retransmit timer for commands */ + int cretries; /* Command retry counter */ + struct gsm_control *pending_cmd;/* Our current pending command */ + spinlock_t control_lock; /* Protects the pending command */ + + /* Configuration */ + int adaption; /* 1 or 2 supported */ + u8 ftype; /* UI or UIH */ + int t1, t2; /* Timers in 1/100th of a sec */ + int n2; /* Retry count */ + + /* Statistics (not currently exposed) */ + unsigned long bad_fcs; + unsigned long malformed; + unsigned long io_error; + unsigned long bad_size; + unsigned long unsupported; +}; + + +/* + * Mux objects - needed so that we can translate a tty index into the + * relevant mux and DLCI. + */ + +#define MAX_MUX 4 /* 256 minors */ +static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ +static spinlock_t gsm_mux_lock; + +/* + * This section of the driver logic implements the GSM encodings + * both the basic and the 'advanced'. Reliable transport is not + * supported. + */ + +#define CR 0x02 +#define EA 0x01 +#define PF 0x10 + +/* I is special: the rest are ..*/ +#define RR 0x01 +#define UI 0x03 +#define RNR 0x05 +#define REJ 0x09 +#define DM 0x0F +#define SABM 0x2F +#define DISC 0x43 +#define UA 0x63 +#define UIH 0xEF + +/* Channel commands */ +#define CMD_NSC 0x09 +#define CMD_TEST 0x11 +#define CMD_PSC 0x21 +#define CMD_RLS 0x29 +#define CMD_FCOFF 0x31 +#define CMD_PN 0x41 +#define CMD_RPN 0x49 +#define CMD_FCON 0x51 +#define CMD_CLD 0x61 +#define CMD_SNC 0x69 +#define CMD_MSC 0x71 + +/* Virtual modem bits */ +#define MDM_FC 0x01 +#define MDM_RTC 0x02 +#define MDM_RTR 0x04 +#define MDM_IC 0x20 +#define MDM_DV 0x40 + +#define GSM0_SOF 0xF9 +#define GSM1_SOF 0x7E +#define GSM1_ESCAPE 0x7D +#define GSM1_ESCAPE_BITS 0x20 +#define XON 0x11 +#define XOFF 0x13 + +static const struct tty_port_operations gsm_port_ops; + +/* + * CRC table for GSM 0710 + */ + +static const u8 gsm_fcs8[256] = { + 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, + 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, + 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, + 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, + 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, + 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, + 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, + 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, + 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, + 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, + 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, + 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, + 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, + 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, + 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, + 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, + 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, + 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, + 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, + 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, + 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, + 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, + 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, + 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, + 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, + 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, + 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, + 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, + 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, + 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, + 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, + 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF +}; + +#define INIT_FCS 0xFF +#define GOOD_FCS 0xCF + +/** + * gsm_fcs_add - update FCS + * @fcs: Current FCS + * @c: Next data + * + * Update the FCS to include c. Uses the algorithm in the specification + * notes. + */ + +static inline u8 gsm_fcs_add(u8 fcs, u8 c) +{ + return gsm_fcs8[fcs ^ c]; +} + +/** + * gsm_fcs_add_block - update FCS for a block + * @fcs: Current FCS + * @c: buffer of data + * @len: length of buffer + * + * Update the FCS to include c. Uses the algorithm in the specification + * notes. + */ + +static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) +{ + while (len--) + fcs = gsm_fcs8[fcs ^ *c++]; + return fcs; +} + +/** + * gsm_read_ea - read a byte into an EA + * @val: variable holding value + * c: byte going into the EA + * + * Processes one byte of an EA. Updates the passed variable + * and returns 1 if the EA is now completely read + */ + +static int gsm_read_ea(unsigned int *val, u8 c) +{ + /* Add the next 7 bits into the value */ + *val <<= 7; + *val |= c >> 1; + /* Was this the last byte of the EA 1 = yes*/ + return c & EA; +} + +/** + * gsm_encode_modem - encode modem data bits + * @dlci: DLCI to encode from + * + * Returns the correct GSM encoded modem status bits (6 bit field) for + * the current status of the DLCI and attached tty object + */ + +static u8 gsm_encode_modem(const struct gsm_dlci *dlci) +{ + u8 modembits = 0; + /* FC is true flow control not modem bits */ + if (dlci->throttled) + modembits |= MDM_FC; + if (dlci->modem_tx & TIOCM_DTR) + modembits |= MDM_RTC; + if (dlci->modem_tx & TIOCM_RTS) + modembits |= MDM_RTR; + if (dlci->modem_tx & TIOCM_RI) + modembits |= MDM_IC; + if (dlci->modem_tx & TIOCM_CD) + modembits |= MDM_DV; + return modembits; +} + +/** + * gsm_print_packet - display a frame for debug + * @hdr: header to print before decode + * @addr: address EA from the frame + * @cr: C/R bit from the frame + * @control: control including PF bit + * @data: following data bytes + * @dlen: length of data + * + * Displays a packet in human readable format for debugging purposes. The + * style is based on amateur radio LAP-B dump display. + */ + +static void gsm_print_packet(const char *hdr, int addr, int cr, + u8 control, const u8 *data, int dlen) +{ + if (!(debug & 1)) + return; + + printk(KERN_INFO "%s %d) %c: ", hdr, addr, "RC"[cr]); + + switch (control & ~PF) { + case SABM: + printk(KERN_CONT "SABM"); + break; + case UA: + printk(KERN_CONT "UA"); + break; + case DISC: + printk(KERN_CONT "DISC"); + break; + case DM: + printk(KERN_CONT "DM"); + break; + case UI: + printk(KERN_CONT "UI"); + break; + case UIH: + printk(KERN_CONT "UIH"); + break; + default: + if (!(control & 0x01)) { + printk(KERN_CONT "I N(S)%d N(R)%d", + (control & 0x0E) >> 1, (control & 0xE)>> 5); + } else switch (control & 0x0F) { + case RR: + printk("RR(%d)", (control & 0xE0) >> 5); + break; + case RNR: + printk("RNR(%d)", (control & 0xE0) >> 5); + break; + case REJ: + printk("REJ(%d)", (control & 0xE0) >> 5); + break; + default: + printk(KERN_CONT "[%02X]", control); + } + } + + if (control & PF) + printk(KERN_CONT "(P)"); + else + printk(KERN_CONT "(F)"); + + if (dlen) { + int ct = 0; + while (dlen--) { + if (ct % 8 == 0) + printk(KERN_CONT "\n "); + printk(KERN_CONT "%02X ", *data++); + ct++; + } + } + printk(KERN_CONT "\n"); +} + + +/* + * Link level transmission side + */ + +/** + * gsm_stuff_packet - bytestuff a packet + * @ibuf: input + * @obuf: output + * @len: length of input + * + * Expand a buffer by bytestuffing it. The worst case size change + * is doubling and the caller is responsible for handing out + * suitable sized buffers. + */ + +static int gsm_stuff_frame(const u8 *input, u8 *output, int len) +{ + int olen = 0; + while (len--) { + if (*input == GSM1_SOF || *input == GSM1_ESCAPE + || *input == XON || *input == XOFF) { + *output++ = GSM1_ESCAPE; + *output++ = *input++ ^ GSM1_ESCAPE_BITS; + olen++; + } else + *output++ = *input++; + olen++; + } + return olen; +} + +static void hex_packet(const unsigned char *p, int len) +{ + int i; + for (i = 0; i < len; i++) { + if (i && (i % 16) == 0) + printk("\n"); + printk("%02X ", *p++); + } + printk("\n"); +} + +/** + * gsm_send - send a control frame + * @gsm: our GSM mux + * @addr: address for control frame + * @cr: command/response bit + * @control: control byte including PF bit + * + * Format up and transmit a control frame. These do not go via the + * queueing logic as they should be transmitted ahead of data when + * they are needed. + * + * FIXME: Lock versus data TX path + */ + +static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) +{ + int len; + u8 cbuf[10]; + u8 ibuf[3]; + + switch (gsm->encoding) { + case 0: + cbuf[0] = GSM0_SOF; + cbuf[1] = (addr << 2) | (cr << 1) | EA; + cbuf[2] = control; + cbuf[3] = EA; /* Length of data = 0 */ + cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); + cbuf[5] = GSM0_SOF; + len = 6; + break; + case 1: + case 2: + /* Control frame + packing (but not frame stuffing) in mode 1 */ + ibuf[0] = (addr << 2) | (cr << 1) | EA; + ibuf[1] = control; + ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); + /* Stuffing may double the size worst case */ + len = gsm_stuff_frame(ibuf, cbuf + 1, 3); + /* Now add the SOF markers */ + cbuf[0] = GSM1_SOF; + cbuf[len + 1] = GSM1_SOF; + /* FIXME: we can omit the lead one in many cases */ + len += 2; + break; + default: + WARN_ON(1); + return; + } + gsm->output(gsm, cbuf, len); + gsm_print_packet("-->", addr, cr, control, NULL, 0); +} + +/** + * gsm_response - send a control response + * @gsm: our GSM mux + * @addr: address for control frame + * @control: control byte including PF bit + * + * Format up and transmit a link level response frame. + */ + +static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) +{ + gsm_send(gsm, addr, 0, control); +} + +/** + * gsm_command - send a control command + * @gsm: our GSM mux + * @addr: address for control frame + * @control: control byte including PF bit + * + * Format up and transmit a link level command frame. + */ + +static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) +{ + gsm_send(gsm, addr, 1, control); +} + +/* Data transmission */ + +#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ + +/** + * gsm_data_alloc - allocate data frame + * @gsm: GSM mux + * @addr: DLCI address + * @len: length excluding header and FCS + * @ctrl: control byte + * + * Allocate a new data buffer for sending frames with data. Space is left + * at the front for header bytes but that is treated as an implementation + * detail and not for the high level code to use + */ + +static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, + u8 ctrl) +{ + struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, + GFP_ATOMIC); + if (m == NULL) + return NULL; + m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ + m->len = len; + m->addr = addr; + m->ctrl = ctrl; + m->next = NULL; + return m; +} + +/** + * gsm_data_kick - poke the queue + * @gsm: GSM Mux + * + * The tty device has called us to indicate that room has appeared in + * the transmit queue. Ram more data into the pipe if we have any + * + * FIXME: lock against link layer control transmissions + */ + +static void gsm_data_kick(struct gsm_mux *gsm) +{ + struct gsm_msg *msg = gsm->tx_head; + int len; + int skip_sof = 0; + + /* FIXME: We need to apply this solely to data messages */ + if (gsm->constipated) + return; + + while (gsm->tx_head != NULL) { + msg = gsm->tx_head; + if (gsm->encoding != 0) { + gsm->txframe[0] = GSM1_SOF; + len = gsm_stuff_frame(msg->data, + gsm->txframe + 1, msg->len); + gsm->txframe[len + 1] = GSM1_SOF; + len += 2; + } else { + gsm->txframe[0] = GSM0_SOF; + memcpy(gsm->txframe + 1 , msg->data, msg->len); + gsm->txframe[msg->len + 1] = GSM0_SOF; + len = msg->len + 2; + } + + if (debug & 4) { + printk("gsm_data_kick: \n"); + hex_packet(gsm->txframe, len); + } + + if (gsm->output(gsm, gsm->txframe + skip_sof, + len - skip_sof) < 0) + break; + /* FIXME: Can eliminate one SOF in many more cases */ + gsm->tx_head = msg->next; + if (gsm->tx_head == NULL) + gsm->tx_tail = NULL; + gsm->tx_bytes -= msg->len; + kfree(msg); + /* For a burst of frames skip the extra SOF within the + burst */ + skip_sof = 1; + } +} + +/** + * __gsm_data_queue - queue a UI or UIH frame + * @dlci: DLCI sending the data + * @msg: message queued + * + * Add data to the transmit queue and try and get stuff moving + * out of the mux tty if not already doing so. The Caller must hold + * the gsm tx lock. + */ + +static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) +{ + struct gsm_mux *gsm = dlci->gsm; + u8 *dp = msg->data; + u8 *fcs = dp + msg->len; + + /* Fill in the header */ + if (gsm->encoding == 0) { + if (msg->len < 128) + *--dp = (msg->len << 1) | EA; + else { + *--dp = (msg->len >> 6) | EA; + *--dp = (msg->len & 127) << 1; + } + } + + *--dp = msg->ctrl; + if (gsm->initiator) + *--dp = (msg->addr << 2) | 2 | EA; + else + *--dp = (msg->addr << 2) | EA; + *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); + /* Ugly protocol layering violation */ + if (msg->ctrl == UI || msg->ctrl == (UI|PF)) + *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); + *fcs = 0xFF - *fcs; + + gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, + msg->data, msg->len); + + /* Move the header back and adjust the length, also allow for the FCS + now tacked on the end */ + msg->len += (msg->data - dp) + 1; + msg->data = dp; + + /* Add to the actual output queue */ + if (gsm->tx_tail) + gsm->tx_tail->next = msg; + else + gsm->tx_head = msg; + gsm->tx_tail = msg; + gsm->tx_bytes += msg->len; + gsm_data_kick(gsm); +} + +/** + * gsm_data_queue - queue a UI or UIH frame + * @dlci: DLCI sending the data + * @msg: message queued + * + * Add data to the transmit queue and try and get stuff moving + * out of the mux tty if not already doing so. Take the + * the gsm tx lock and dlci lock. + */ + +static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) +{ + unsigned long flags; + spin_lock_irqsave(&dlci->gsm->tx_lock, flags); + __gsm_data_queue(dlci, msg); + spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); +} + +/** + * gsm_dlci_data_output - try and push data out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull data from + * + * Pull data from a DLCI and send it into the transmit queue if there + * is data. Keep to the MRU of the mux. This path handles the usual tty + * interface which is a byte stream with optional modem data. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) +{ + struct gsm_msg *msg; + u8 *dp; + int len, size; + int h = dlci->adaption - 1; + + len = kfifo_len(dlci->fifo); + if (len == 0) + return 0; + + /* MTU/MRU count only the data bits */ + if (len > gsm->mtu) + len = gsm->mtu; + + size = len + h; + + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + /* FIXME: need a timer or something to kick this so it can't + get stuck with no work outstanding and no buffer free */ + if (msg == NULL) + return -ENOMEM; + dp = msg->data; + switch (dlci->adaption) { + case 1: /* Unstructured */ + break; + case 2: /* Unstructed with modem bits. Always one byte as we never + send inline break data */ + *dp += gsm_encode_modem(dlci); + len--; + break; + } + WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); + __gsm_data_queue(dlci, msg); + /* Bytes of data we used up */ + return size; +} + +/** + * gsm_dlci_data_output_framed - try and push data out of a DLCI + * @gsm: mux + * @dlci: the DLCI to pull data from + * + * Pull data from a DLCI and send it into the transmit queue if there + * is data. Keep to the MRU of the mux. This path handles framed data + * queued as skbuffs to the DLCI. + * + * Caller must hold the tx_lock of the mux. + */ + +static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, + struct gsm_dlci *dlci) +{ + struct gsm_msg *msg; + u8 *dp; + int len, size; + int last = 0, first = 0; + int overhead = 0; + + /* One byte per frame is used for B/F flags */ + if (dlci->adaption == 4) + overhead = 1; + + /* dlci->skb is locked by tx_lock */ + if (dlci->skb == NULL) { + dlci->skb = skb_dequeue(&dlci->skb_list); + if (dlci->skb == NULL) + return 0; + first = 1; + } + len = dlci->skb->len + overhead; + + /* MTU/MRU count only the data bits */ + if (len > gsm->mtu) { + if (dlci->adaption == 3) { + /* Over long frame, bin it */ + kfree_skb(dlci->skb); + dlci->skb = NULL; + return 0; + } + len = gsm->mtu; + } else + last = 1; + + size = len + overhead; + msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); + + /* FIXME: need a timer or something to kick this so it can't + get stuck with no work outstanding and no buffer free */ + if (msg == NULL) + return -ENOMEM; + dp = msg->data; + + if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ + /* Flag byte to carry the start/end info */ + *dp++ = last << 7 | first << 6 | 1; /* EA */ + len--; + } + memcpy(dp, skb_pull(dlci->skb, len), len); + __gsm_data_queue(dlci, msg); + if (last) + dlci->skb = NULL; + return size; +} + +/** + * gsm_dlci_data_sweep - look for data to send + * @gsm: the GSM mux + * + * Sweep the GSM mux channels in priority order looking for ones with + * data to send. We could do with optimising this scan a bit. We aim + * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit + * TX_THRESH_LO we get called again + * + * FIXME: We should round robin between groups and in theory you can + * renegotiate DLCI priorities with optional stuff. Needs optimising. + */ + +static void gsm_dlci_data_sweep(struct gsm_mux *gsm) +{ + int len; + /* Priority ordering: We should do priority with RR of the groups */ + int i = 1; + + while (i < NUM_DLCI) { + struct gsm_dlci *dlci; + + if (gsm->tx_bytes > TX_THRESH_HI) + break; + dlci = gsm->dlci[i]; + if (dlci == NULL || dlci->constipated) { + i++; + continue; + } + if (dlci->adaption < 3) + len = gsm_dlci_data_output(gsm, dlci); + else + len = gsm_dlci_data_output_framed(gsm, dlci); + if (len < 0) + break; + /* DLCI empty - try the next */ + if (len == 0) + i++; + } +} + +/** + * gsm_dlci_data_kick - transmit if possible + * @dlci: DLCI to kick + * + * Transmit data from this DLCI if the queue is empty. We can't rely on + * a tty wakeup except when we filled the pipe so we need to fire off + * new data ourselves in other cases. + */ + +static void gsm_dlci_data_kick(struct gsm_dlci *dlci) +{ + unsigned long flags; + + spin_lock_irqsave(&dlci->gsm->tx_lock, flags); + /* If we have nothing running then we need to fire up */ + if (dlci->gsm->tx_bytes == 0) + gsm_dlci_data_output(dlci->gsm, dlci); + else if (dlci->gsm->tx_bytes < TX_THRESH_LO) + gsm_dlci_data_sweep(dlci->gsm); + spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); +} + +/* + * Control message processing + */ + + +/** + * gsm_control_reply - send a response frame to a control + * @gsm: gsm channel + * @cmd: the command to use + * @data: data to follow encoded info + * @dlen: length of data + * + * Encode up and queue a UI/UIH frame containing our response. + */ + +static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, + int dlen) +{ + struct gsm_msg *msg; + msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); + msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ + msg->data[1] = (dlen << 1) | EA; + memcpy(msg->data + 2, data, dlen); + gsm_data_queue(gsm->dlci[0], msg); +} + +/** + * gsm_process_modem - process received modem status + * @tty: virtual tty bound to the DLCI + * @dlci: DLCI to affect + * @modem: modem bits (full EA) + * + * Used when a modem control message or line state inline in adaption + * layer 2 is processed. Sort out the local modem state and throttles + */ + +static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, + u32 modem) +{ + int mlines = 0; + u8 brk = modem >> 6; + + /* Flow control/ready to communicate */ + if (modem & MDM_FC) { + /* Need to throttle our output on this device */ + dlci->constipated = 1; + } + if (modem & MDM_RTC) { + mlines |= TIOCM_DSR | TIOCM_DTR; + dlci->constipated = 0; + gsm_dlci_data_kick(dlci); + } + /* Map modem bits */ + if (modem & MDM_RTR) + mlines |= TIOCM_RTS | TIOCM_CTS; + if (modem & MDM_IC) + mlines |= TIOCM_RI; + if (modem & MDM_DV) + mlines |= TIOCM_CD; + + /* Carrier drop -> hangup */ + if (tty) { + if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) + if (!(tty->termios->c_cflag & CLOCAL)) + tty_hangup(tty); + if (brk & 0x01) + tty_insert_flip_char(tty, 0, TTY_BREAK); + } + dlci->modem_rx = mlines; +} + +/** + * gsm_control_modem - modem status received + * @gsm: GSM channel + * @data: data following command + * @clen: command length + * + * We have received a modem status control message. This is used by + * the GSM mux protocol to pass virtual modem line status and optionally + * to indicate break signals. Unpack it, convert to Linux representation + * and if need be stuff a break message down the tty. + */ + +static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) +{ + unsigned int addr = 0; + unsigned int modem = 0; + struct gsm_dlci *dlci; + int len = clen; + u8 *dp = data; + struct tty_struct *tty; + + while (gsm_read_ea(&addr, *dp++) == 0) { + len--; + if (len == 0) + return; + } + /* Must be at least one byte following the EA */ + len--; + if (len <= 0) + return; + + addr >>= 1; + /* Closed port, or invalid ? */ + if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) + return; + dlci = gsm->dlci[addr]; + + while (gsm_read_ea(&modem, *dp++) == 0) { + len--; + if (len == 0) + return; + } + tty = tty_port_tty_get(&dlci->port); + gsm_process_modem(tty, dlci, modem); + if (tty) { + tty_wakeup(tty); + tty_kref_put(tty); + } + gsm_control_reply(gsm, CMD_MSC, data, clen); +} + +/** + * gsm_control_rls - remote line status + * @gsm: GSM channel + * @data: data bytes + * @clen: data length + * + * The modem sends us a two byte message on the control channel whenever + * it wishes to send us an error state from the virtual link. Stuff + * this into the uplink tty if present + */ + +static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) +{ + struct tty_struct *tty; + unsigned int addr = 0 ; + u8 bits; + int len = clen; + u8 *dp = data; + + while (gsm_read_ea(&addr, *dp++) == 0) { + len--; + if (len == 0) + return; + } + /* Must be at least one byte following ea */ + len--; + if (len <= 0) + return; + addr >>= 1; + /* Closed port, or invalid ? */ + if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) + return; + /* No error ? */ + bits = *dp; + if ((bits & 1) == 0) + return; + /* See if we have an uplink tty */ + tty = tty_port_tty_get(&gsm->dlci[addr]->port); + + if (tty) { + if (bits & 2) + tty_insert_flip_char(tty, 0, TTY_OVERRUN); + if (bits & 4) + tty_insert_flip_char(tty, 0, TTY_PARITY); + if (bits & 8) + tty_insert_flip_char(tty, 0, TTY_FRAME); + tty_flip_buffer_push(tty); + tty_kref_put(tty); + } + gsm_control_reply(gsm, CMD_RLS, data, clen); +} + +static void gsm_dlci_begin_close(struct gsm_dlci *dlci); + +/** + * gsm_control_message - DLCI 0 control processing + * @gsm: our GSM mux + * @command: the command EA + * @data: data beyond the command/length EAs + * @clen: length + * + * Input processor for control messages from the other end of the link. + * Processes the incoming request and queues a response frame or an + * NSC response if not supported + */ + +static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, + u8 *data, int clen) +{ + u8 buf[1]; + switch (command) { + case CMD_CLD: { + struct gsm_dlci *dlci = gsm->dlci[0]; + /* Modem wishes to close down */ + if (dlci) { + dlci->dead = 1; + gsm->dead = 1; + gsm_dlci_begin_close(dlci); + } + } + break; + case CMD_TEST: + /* Modem wishes to test, reply with the data */ + gsm_control_reply(gsm, CMD_TEST, data, clen); + break; + case CMD_FCON: + /* Modem wants us to STFU */ + gsm->constipated = 1; + gsm_control_reply(gsm, CMD_FCON, NULL, 0); + break; + case CMD_FCOFF: + /* Modem can accept data again */ + gsm->constipated = 0; + gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); + /* Kick the link in case it is idling */ + gsm_data_kick(gsm); + break; + case CMD_MSC: + /* Out of band modem line change indicator for a DLCI */ + gsm_control_modem(gsm, data, clen); + break; + case CMD_RLS: + /* Out of band error reception for a DLCI */ + gsm_control_rls(gsm, data, clen); + break; + case CMD_PSC: + /* Modem wishes to enter power saving state */ + gsm_control_reply(gsm, CMD_PSC, NULL, 0); + break; + /* Optional unsupported commands */ + case CMD_PN: /* Parameter negotiation */ + case CMD_RPN: /* Remote port negotation */ + case CMD_SNC: /* Service negotation command */ + default: + /* Reply to bad commands with an NSC */ + buf[0] = command; + gsm_control_reply(gsm, CMD_NSC, buf, 1); + break; + } +} + +/** + * gsm_control_response - process a response to our control + * @gsm: our GSM mux + * @command: the command (response) EA + * @data: data beyond the command/length EA + * @clen: length + * + * Process a response to an outstanding command. We only allow a single + * control message in flight so this is fairly easy. All the clean up + * is done by the caller, we just update the fields, flag it as done + * and return + */ + +static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, + u8 *data, int clen) +{ + struct gsm_control *ctrl; + unsigned long flags; + + spin_lock_irqsave(&gsm->control_lock, flags); + + ctrl = gsm->pending_cmd; + /* Does the reply match our command */ + command |= 1; + if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { + /* Our command was replied to, kill the retry timer */ + del_timer(&gsm->t2_timer); + gsm->pending_cmd = NULL; + /* Rejected by the other end */ + if (command == CMD_NSC) + ctrl->error = -EOPNOTSUPP; + ctrl->done = 1; + wake_up(&gsm->event); + } + spin_unlock_irqrestore(&gsm->control_lock, flags); +} + +/** + * gsm_control_transmit - send control packet + * @gsm: gsm mux + * @ctrl: frame to send + * + * Send out a pending control command (called under control lock) + */ + +static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) +{ + struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, + gsm->ftype|PF); + if (msg == NULL) + return; + msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ + memcpy(msg->data + 1, ctrl->data, ctrl->len); + gsm_data_queue(gsm->dlci[0], msg); +} + +/** + * gsm_control_retransmit - retransmit a control frame + * @data: pointer to our gsm object + * + * Called off the T2 timer expiry in order to retransmit control frames + * that have been lost in the system somewhere. The control_lock protects + * us from colliding with another sender or a receive completion event. + * In that situation the timer may still occur in a small window but + * gsm->pending_cmd will be NULL and we just let the timer expire. + */ + +static void gsm_control_retransmit(unsigned long data) +{ + struct gsm_mux *gsm = (struct gsm_mux *)data; + struct gsm_control *ctrl; + unsigned long flags; + spin_lock_irqsave(&gsm->control_lock, flags); + ctrl = gsm->pending_cmd; + if (ctrl) { + gsm->cretries--; + if (gsm->cretries == 0) { + gsm->pending_cmd = NULL; + ctrl->error = -ETIMEDOUT; + ctrl->done = 1; + spin_unlock_irqrestore(&gsm->control_lock, flags); + wake_up(&gsm->event); + return; + } + gsm_control_transmit(gsm, ctrl); + mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); + } + spin_unlock_irqrestore(&gsm->control_lock, flags); +} + +/** + * gsm_control_send - send a control frame on DLCI 0 + * @gsm: the GSM channel + * @command: command to send including CR bit + * @data: bytes of data (must be kmalloced) + * @len: length of the block to send + * + * Queue and dispatch a control command. Only one command can be + * active at a time. In theory more can be outstanding but the matching + * gets really complicated so for now stick to one outstanding. + */ + +static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, + unsigned int command, u8 *data, int clen) +{ + struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), + GFP_KERNEL); + unsigned long flags; + if (ctrl == NULL) + return NULL; +retry: + wait_event(gsm->event, gsm->pending_cmd == NULL); + spin_lock_irqsave(&gsm->control_lock, flags); + if (gsm->pending_cmd != NULL) { + spin_unlock_irqrestore(&gsm->control_lock, flags); + goto retry; + } + ctrl->cmd = command; + ctrl->data = data; + ctrl->len = clen; + gsm->pending_cmd = ctrl; + gsm->cretries = gsm->n2; + mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); + gsm_control_transmit(gsm, ctrl); + spin_unlock_irqrestore(&gsm->control_lock, flags); + return ctrl; +} + +/** + * gsm_control_wait - wait for a control to finish + * @gsm: GSM mux + * @control: control we are waiting on + * + * Waits for the control to complete or time out. Frees any used + * resources and returns 0 for success, or an error if the remote + * rejected or ignored the request. + */ + +static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) +{ + int err; + wait_event(gsm->event, control->done == 1); + err = control->error; + kfree(control); + return err; +} + + +/* + * DLCI level handling: Needs krefs + */ + +/* + * State transitions and timers + */ + +/** + * gsm_dlci_close - a DLCI has closed + * @dlci: DLCI that closed + * + * Perform processing when moving a DLCI into closed state. If there + * is an attached tty this is hung up + */ + +static void gsm_dlci_close(struct gsm_dlci *dlci) +{ + del_timer(&dlci->t1); + if (debug & 8) + printk("DLCI %d goes closed.\n", dlci->addr); + dlci->state = DLCI_CLOSED; + if (dlci->addr != 0) { + struct tty_struct *tty = tty_port_tty_get(&dlci->port); + if (tty) { + tty_hangup(tty); + tty_kref_put(tty); + } + kfifo_reset(dlci->fifo); + } else + dlci->gsm->dead = 1; + wake_up(&dlci->gsm->event); + /* A DLCI 0 close is a MUX termination so we need to kick that + back to userspace somehow */ +} + +/** + * gsm_dlci_open - a DLCI has opened + * @dlci: DLCI that opened + * + * Perform processing when moving a DLCI into open state. + */ + +static void gsm_dlci_open(struct gsm_dlci *dlci) +{ + /* Note that SABM UA .. SABM UA first UA lost can mean that we go + open -> open */ + del_timer(&dlci->t1); + /* This will let a tty open continue */ + dlci->state = DLCI_OPEN; + if (debug & 8) + printk("DLCI %d goes open.\n", dlci->addr); + wake_up(&dlci->gsm->event); +} + +/** + * gsm_dlci_t1 - T1 timer expiry + * @dlci: DLCI that opened + * + * The T1 timer handles retransmits of control frames (essentially of + * SABM and DISC). We resend the command until the retry count runs out + * in which case an opening port goes back to closed and a closing port + * is simply put into closed state (any further frames from the other + * end will get a DM response) + */ + +static void gsm_dlci_t1(unsigned long data) +{ + struct gsm_dlci *dlci = (struct gsm_dlci *)data; + struct gsm_mux *gsm = dlci->gsm; + + switch (dlci->state) { + case DLCI_OPENING: + dlci->retries--; + if (dlci->retries) { + gsm_command(dlci->gsm, dlci->addr, SABM|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); + } else + gsm_dlci_close(dlci); + break; + case DLCI_CLOSING: + dlci->retries--; + if (dlci->retries) { + gsm_command(dlci->gsm, dlci->addr, DISC|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); + } else + gsm_dlci_close(dlci); + break; + } +} + +/** + * gsm_dlci_begin_open - start channel open procedure + * @dlci: DLCI to open + * + * Commence opening a DLCI from the Linux side. We issue SABM messages + * to the modem which should then reply with a UA, at which point we + * will move into open state. Opening is done asynchronously with retry + * running off timers and the responses. + */ + +static void gsm_dlci_begin_open(struct gsm_dlci *dlci) +{ + struct gsm_mux *gsm = dlci->gsm; + if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) + return; + dlci->retries = gsm->n2; + dlci->state = DLCI_OPENING; + gsm_command(dlci->gsm, dlci->addr, SABM|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); +} + +/** + * gsm_dlci_begin_close - start channel open procedure + * @dlci: DLCI to open + * + * Commence closing a DLCI from the Linux side. We issue DISC messages + * to the modem which should then reply with a UA, at which point we + * will move into closed state. Closing is done asynchronously with retry + * off timers. We may also receive a DM reply from the other end which + * indicates the channel was already closed. + */ + +static void gsm_dlci_begin_close(struct gsm_dlci *dlci) +{ + struct gsm_mux *gsm = dlci->gsm; + if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) + return; + dlci->retries = gsm->n2; + dlci->state = DLCI_CLOSING; + gsm_command(dlci->gsm, dlci->addr, DISC|PF); + mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); +} + +/** + * gsm_dlci_data - data arrived + * @dlci: channel + * @data: block of bytes received + * @len: length of received block + * + * A UI or UIH frame has arrived which contains data for a channel + * other than the control channel. If the relevant virtual tty is + * open we shovel the bits down it, if not we drop them. + */ + +static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int len) +{ + /* krefs .. */ + struct tty_port *port = &dlci->port; + struct tty_struct *tty = tty_port_tty_get(port); + unsigned int modem = 0; + + if (debug & 16) + printk("%d bytes for tty %p\n", len, tty); + if (tty) { + switch (dlci->adaption) { + /* Unsupported types */ + /* Packetised interruptible data */ + case 4: + break; + /* Packetised uininterruptible voice/data */ + case 3: + break; + /* Asynchronous serial with line state in each frame */ + case 2: + while (gsm_read_ea(&modem, *data++) == 0) { + len--; + if (len == 0) + return; + } + gsm_process_modem(tty, dlci, modem); + /* Line state will go via DLCI 0 controls only */ + case 1: + default: + tty_insert_flip_string(tty, data, len); + tty_flip_buffer_push(tty); + } + tty_kref_put(tty); + } +} + +/** + * gsm_dlci_control - data arrived on control channel + * @dlci: channel + * @data: block of bytes received + * @len: length of received block + * + * A UI or UIH frame has arrived which contains data for DLCI 0 the + * control channel. This should contain a command EA followed by + * control data bytes. The command EA contains a command/response bit + * and we divide up the work accordingly. + */ + +static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) +{ + /* See what command is involved */ + unsigned int command = 0; + while (len-- > 0) { + if (gsm_read_ea(&command, *data++) == 1) { + int clen = *data++; + len--; + /* FIXME: this is properly an EA */ + clen >>= 1; + /* Malformed command ? */ + if (clen > len) + return; + if (command & 1) + gsm_control_message(dlci->gsm, command, + data, clen); + else + gsm_control_response(dlci->gsm, command, + data, clen); + return; + } + } +} + +/* + * Allocate/Free DLCI channels + */ + +/** + * gsm_dlci_alloc - allocate a DLCI + * @gsm: GSM mux + * @addr: address of the DLCI + * + * Allocate and install a new DLCI object into the GSM mux. + * + * FIXME: review locking races + */ + +static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) +{ + struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); + if (dlci == NULL) + return NULL; + spin_lock_init(&dlci->lock); + dlci->fifo = &dlci->_fifo; + if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { + kfree(dlci); + return NULL; + } + + skb_queue_head_init(&dlci->skb_list); + init_timer(&dlci->t1); + dlci->t1.function = gsm_dlci_t1; + dlci->t1.data = (unsigned long)dlci; + tty_port_init(&dlci->port); + dlci->port.ops = &gsm_port_ops; + dlci->gsm = gsm; + dlci->addr = addr; + dlci->adaption = gsm->adaption; + dlci->state = DLCI_CLOSED; + if (addr) + dlci->data = gsm_dlci_data; + else + dlci->data = gsm_dlci_command; + gsm->dlci[addr] = dlci; + return dlci; +} + +/** + * gsm_dlci_free - release DLCI + * @dlci: DLCI to destroy + * + * Free up a DLCI. Currently to keep the lifetime rules sane we only + * clean up DLCI objects when the MUX closes rather than as the port + * is closed down on both the tty and mux levels. + * + * Can sleep. + */ +static void gsm_dlci_free(struct gsm_dlci *dlci) +{ + struct tty_struct *tty = tty_port_tty_get(&dlci->port); + if (tty) { + tty_vhangup(tty); + tty_kref_put(tty); + } + del_timer_sync(&dlci->t1); + dlci->gsm->dlci[dlci->addr] = NULL; + kfifo_free(dlci->fifo); + kfree(dlci); +} + + +/* + * LAPBish link layer logic + */ + +/** + * gsm_queue - a GSM frame is ready to process + * @gsm: pointer to our gsm mux + * + * At this point in time a frame has arrived and been demangled from + * the line encoding. All the differences between the encodings have + * been handled below us and the frame is unpacked into the structures. + * The fcs holds the header FCS but any data FCS must be added here. + */ + +static void gsm_queue(struct gsm_mux *gsm) +{ + struct gsm_dlci *dlci; + u8 cr; + int address; + /* We have to sneak a look at the packet body to do the FCS. + A somewhat layering violation in the spec */ + + if ((gsm->control & ~PF) == UI) + gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); + if (gsm->fcs != GOOD_FCS) { + gsm->bad_fcs++; + if (debug & 4) + printk("BAD FCS %02x\n", gsm->fcs); + return; + } + address = gsm->address >> 1; + if (address >= NUM_DLCI) + goto invalid; + + cr = gsm->address & 1; /* C/R bit */ + + gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); + + cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ + dlci = gsm->dlci[address]; + + switch (gsm->control) { + case SABM|PF: + if (cr == 0) + goto invalid; + if (dlci == NULL) + dlci = gsm_dlci_alloc(gsm, address); + if (dlci == NULL) + return; + if (dlci->dead) + gsm_response(gsm, address, DM); + else { + gsm_response(gsm, address, UA); + gsm_dlci_open(dlci); + } + break; + case DISC|PF: + if (cr == 0) + goto invalid; + if (dlci == NULL || dlci->state == DLCI_CLOSED) { + gsm_response(gsm, address, DM); + return; + } + /* Real close complete */ + gsm_response(gsm, address, UA); + gsm_dlci_close(dlci); + break; + case UA: + case UA|PF: + if (cr == 0 || dlci == NULL) + break; + switch (dlci->state) { + case DLCI_CLOSING: + gsm_dlci_close(dlci); + break; + case DLCI_OPENING: + gsm_dlci_open(dlci); + break; + } + break; + case DM: /* DM can be valid unsolicited */ + case DM|PF: + if (cr) + goto invalid; + if (dlci == NULL) + return; + gsm_dlci_close(dlci); + break; + case UI: + case UI|PF: + case UIH: + case UIH|PF: +#if 0 + if (cr) + goto invalid; +#endif + if (dlci == NULL || dlci->state != DLCI_OPEN) { + gsm_command(gsm, address, DM|PF); + return; + } + dlci->data(dlci, gsm->buf, gsm->len); + break; + default: + goto invalid; + } + return; +invalid: + gsm->malformed++; + return; +} + + +/** + * gsm0_receive - perform processing for non-transparency + * @gsm: gsm data for this ldisc instance + * @c: character + * + * Receive bytes in gsm mode 0 + */ + +static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) +{ + switch (gsm->state) { + case GSM_SEARCH: /* SOF marker */ + if (c == GSM0_SOF) { + gsm->state = GSM_ADDRESS; + gsm->address = 0; + gsm->len = 0; + gsm->fcs = INIT_FCS; + } + break; /* Address EA */ + case GSM_ADDRESS: + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->address, c)) + gsm->state = GSM_CONTROL; + break; + case GSM_CONTROL: /* Control Byte */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + gsm->control = c; + gsm->state = GSM_LEN; + break; + case GSM_LEN: /* Length EA */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->len, c)) { + if (gsm->len > gsm->mru) { + gsm->bad_size++; + gsm->state = GSM_SEARCH; + break; + } + gsm->count = 0; + gsm->state = GSM_DATA; + } + break; + case GSM_DATA: /* Data */ + gsm->buf[gsm->count++] = c; + if (gsm->count == gsm->len) + gsm->state = GSM_FCS; + break; + case GSM_FCS: /* FCS follows the packet */ + gsm->fcs = c; + gsm_queue(gsm); + /* And then back for the next frame */ + gsm->state = GSM_SEARCH; + break; + } +} + +/** + * gsm0_receive - perform processing for non-transparency + * @gsm: gsm data for this ldisc instance + * @c: character + * + * Receive bytes in mode 1 (Advanced option) + */ + +static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) +{ + if (c == GSM1_SOF) { + /* EOF is only valid in frame if we have got to the data state + and received at least one byte (the FCS) */ + if (gsm->state == GSM_DATA && gsm->count) { + /* Extract the FCS */ + gsm->count--; + gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); + gsm->len = gsm->count; + gsm_queue(gsm); + gsm->state = GSM_START; + return; + } + /* Any partial frame was a runt so go back to start */ + if (gsm->state != GSM_START) { + gsm->malformed++; + gsm->state = GSM_START; + } + /* A SOF in GSM_START means we are still reading idling or + framing bytes */ + return; + } + + if (c == GSM1_ESCAPE) { + gsm->escape = 1; + return; + } + + /* Only an unescaped SOF gets us out of GSM search */ + if (gsm->state == GSM_SEARCH) + return; + + if (gsm->escape) { + c ^= GSM1_ESCAPE_BITS; + gsm->escape = 0; + } + switch (gsm->state) { + case GSM_START: /* First byte after SOF */ + gsm->address = 0; + gsm->state = GSM_ADDRESS; + gsm->fcs = INIT_FCS; + /* Drop through */ + case GSM_ADDRESS: /* Address continuation */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + if (gsm_read_ea(&gsm->address, c)) + gsm->state = GSM_CONTROL; + break; + case GSM_CONTROL: /* Control Byte */ + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + gsm->control = c; + gsm->count = 0; + gsm->state = GSM_DATA; + break; + case GSM_DATA: /* Data */ + if (gsm->count > gsm->mru ) { /* Allow one for the FCS */ + gsm->state = GSM_OVERRUN; + gsm->bad_size++; + } else + gsm->buf[gsm->count++] = c; + break; + case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ + break; + } +} + +/** + * gsm_error - handle tty error + * @gsm: ldisc data + * @data: byte received (may be invalid) + * @flag: error received + * + * Handle an error in the receipt of data for a frame. Currently we just + * go back to hunting for a SOF. + * + * FIXME: better diagnostics ? + */ + +static void gsm_error(struct gsm_mux *gsm, + unsigned char data, unsigned char flag) +{ + gsm->state = GSM_SEARCH; + gsm->io_error++; +} + +/** + * gsm_cleanup_mux - generic GSM protocol cleanup + * @gsm: our mux + * + * Clean up the bits of the mux which are the same for all framing + * protocols. Remove the mux from the mux table, stop all the timers + * and then shut down each device hanging up the channels as we go. + */ + +void gsm_cleanup_mux(struct gsm_mux *gsm) +{ + int i; + struct gsm_dlci *dlci = gsm->dlci[0]; + struct gsm_msg *txq; + + gsm->dead = 1; + + spin_lock(&gsm_mux_lock); + for (i = 0; i < MAX_MUX; i++) { + if (gsm_mux[i] == gsm) { + gsm_mux[i] = NULL; + break; + } + } + spin_unlock(&gsm_mux_lock); + WARN_ON(i == MAX_MUX); + + del_timer_sync(&gsm->t2_timer); + /* Now we are sure T2 has stopped */ + if (dlci) { + dlci->dead = 1; + gsm_dlci_begin_close(dlci); + wait_event_interruptible(gsm->event, + dlci->state == DLCI_CLOSED); + } + /* Free up any link layer users */ + for (i = 0; i < NUM_DLCI; i++) + if (gsm->dlci[i]) + gsm_dlci_free(gsm->dlci[i]); + /* Now wipe the queues */ + for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) { + gsm->tx_head = txq->next; + kfree(txq); + } + gsm->tx_tail = NULL; +} +EXPORT_SYMBOL_GPL(gsm_cleanup_mux); + +/** + * gsm_activate_mux - generic GSM setup + * @gsm: our mux + * + * Set up the bits of the mux which are the same for all framing + * protocols. Add the mux to the mux table so it can be opened and + * finally kick off connecting to DLCI 0 on the modem. + */ + +int gsm_activate_mux(struct gsm_mux *gsm) +{ + struct gsm_dlci *dlci; + int i = 0; + + init_timer(&gsm->t2_timer); + gsm->t2_timer.function = gsm_control_retransmit; + gsm->t2_timer.data = (unsigned long)gsm; + init_waitqueue_head(&gsm->event); + spin_lock_init(&gsm->control_lock); + spin_lock_init(&gsm->tx_lock); + + if (gsm->encoding == 0) + gsm->receive = gsm0_receive; + else + gsm->receive = gsm1_receive; + gsm->error = gsm_error; + + spin_lock(&gsm_mux_lock); + for (i = 0; i < MAX_MUX; i++) { + if (gsm_mux[i] == NULL) { + gsm_mux[i] = gsm; + break; + } + } + spin_unlock(&gsm_mux_lock); + if (i == MAX_MUX) + return -EBUSY; + + dlci = gsm_dlci_alloc(gsm, 0); + if (dlci == NULL) + return -ENOMEM; + gsm->dead = 0; /* Tty opens are now permissible */ + return 0; +} +EXPORT_SYMBOL_GPL(gsm_activate_mux); + +/** + * gsm_free_mux - free up a mux + * @mux: mux to free + * + * Dispose of allocated resources for a dead mux. No refcounting + * at present so the mux must be truely dead. + */ +void gsm_free_mux(struct gsm_mux *gsm) +{ + kfree(gsm->txframe); + kfree(gsm->buf); + kfree(gsm); +} +EXPORT_SYMBOL_GPL(gsm_free_mux); + +/** + * gsm_alloc_mux - allocate a mux + * + * Creates a new mux ready for activation. + */ + +struct gsm_mux *gsm_alloc_mux(void) +{ + struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); + if (gsm == NULL) + return NULL; + gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); + if (gsm->buf == NULL) { + kfree(gsm); + return NULL; + } + gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); + if (gsm->txframe == NULL) { + kfree(gsm->buf); + kfree(gsm); + return NULL; + } + spin_lock_init(&gsm->lock); + + gsm->t1 = T1; + gsm->t2 = T2; + gsm->n2 = N2; + gsm->ftype = UIH; + gsm->initiator = 0; + gsm->adaption = 1; + gsm->encoding = 1; + gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ + gsm->mtu = 64; + gsm->dead = 1; /* Avoid early tty opens */ + + return gsm; +} +EXPORT_SYMBOL_GPL(gsm_alloc_mux); + + + + +/** + * gsmld_output - write to link + * @gsm: our mux + * @data: bytes to output + * @len: size + * + * Write a block of data from the GSM mux to the data channel. This + * will eventually be serialized from above but at the moment isn't. + */ + +static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) +{ + if (tty_write_room(gsm->tty) < len) { + set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); + return -ENOSPC; + } + if (debug & 4) { + printk("-->%d bytes out\n", len); + hex_packet(data, len); + } + gsm->tty->ops->write(gsm->tty, data, len); + return len; +} + +/** + * gsmld_attach_gsm - mode set up + * @tty: our tty structure + * @gsm: our mux + * + * Set up the MUX for basic mode and commence connecting to the + * modem. Currently called from the line discipline set up but + * will need moving to an ioctl path. + */ + +static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) +{ + int ret; + + gsm->tty = tty_kref_get(tty); + gsm->output = gsmld_output; + ret = gsm_activate_mux(gsm); + if (ret != 0) + tty_kref_put(gsm->tty); + return ret; +} + + +/** + * gsmld_detach_gsm - stop doing 0710 mux + * @tty: tty atttached to the mux + * @gsm: mux + * + * Shutdown and then clean up the resources used by the line discipline + */ + +static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) +{ + WARN_ON(tty != gsm->tty); + gsm_cleanup_mux(gsm); + tty_kref_put(gsm->tty); + gsm->tty = NULL; +} + +static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct gsm_mux *gsm = tty->disc_data; + const unsigned char *dp; + char *f; + int i; + char buf[64]; + char flags; + + if (debug & 4) { + printk("Inbytes %dd\n", count); + hex_packet(cp, count); + } + + for (i = count, dp = cp, f = fp; i; i--, dp++) { + flags = *f++; + switch (flags) { + case TTY_NORMAL: + gsm->receive(gsm, *dp); + break; + case TTY_OVERRUN: + case TTY_BREAK: + case TTY_PARITY: + case TTY_FRAME: + gsm->error(gsm, *dp, flags); + break; + default: + printk(KERN_ERR "%s: unknown flag %d\n", + tty_name(tty, buf), flags); + break; + } + } + /* FASYNC if needed ? */ + /* If clogged call tty_throttle(tty); */ +} + +/** + * gsmld_chars_in_buffer - report available bytes + * @tty: tty device + * + * Report the number of characters buffered to be delivered to user + * at this instant in time. + * + * Locking: gsm lock + */ + +static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) +{ + return 0; +} + +/** + * gsmld_flush_buffer - clean input queue + * @tty: terminal device + * + * Flush the input buffer. Called when the line discipline is + * being closed, when the tty layer wants the buffer flushed (eg + * at hangup). + */ + +static void gsmld_flush_buffer(struct tty_struct *tty) +{ +} + +/** + * gsmld_close - close the ldisc for this tty + * @tty: device + * + * Called from the terminal layer when this line discipline is + * being shut down, either because of a close or becsuse of a + * discipline change. The function will not be called while other + * ldisc methods are in progress. + */ + +static void gsmld_close(struct tty_struct *tty) +{ + struct gsm_mux *gsm = tty->disc_data; + + gsmld_detach_gsm(tty, gsm); + + gsmld_flush_buffer(tty); + /* Do other clean up here */ + gsm_free_mux(gsm); +} + +/** + * gsmld_open - open an ldisc + * @tty: terminal to open + * + * Called when this line discipline is being attached to the + * terminal device. Can sleep. Called serialized so that no + * other events will occur in parallel. No further open will occur + * until a close. + */ + +static int gsmld_open(struct tty_struct *tty) +{ + struct gsm_mux *gsm; + + if (tty->ops->write == NULL) + return -EINVAL; + + /* Attach our ldisc data */ + gsm = gsm_alloc_mux(); + if (gsm == NULL) + return -ENOMEM; + + tty->disc_data = gsm; + tty->receive_room = 65536; + + /* Attach the initial passive connection */ + gsm->encoding = 1; + return gsmld_attach_gsm(tty, gsm); +} + +/** + * gsmld_write_wakeup - asynchronous I/O notifier + * @tty: tty device + * + * Required for the ptys, serial driver etc. since processes + * that attach themselves to the master and rely on ASYNC + * IO must be woken up + */ + +static void gsmld_write_wakeup(struct tty_struct *tty) +{ + struct gsm_mux *gsm = tty->disc_data; + unsigned long flags; + + /* Queue poll */ + clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + gsm_data_kick(gsm); + if (gsm->tx_bytes < TX_THRESH_LO) { + spin_lock_irqsave(&gsm->tx_lock, flags); + gsm_dlci_data_sweep(gsm); + spin_unlock_irqrestore(&gsm->tx_lock, flags); + } +} + +/** + * gsmld_read - read function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Perform reads for the line discipline. We are guaranteed that the + * line discipline will not be closed under us but we may get multiple + * parallel readers and must handle this ourselves. We may also get + * a hangup. Always called in user context, may sleep. + * + * This code must be sure never to sleep through a hangup. + */ + +static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, + unsigned char __user *buf, size_t nr) +{ + return -EOPNOTSUPP; +} + +/** + * gsmld_write - write function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Called when the owner of the device wants to send a frame + * itself (or some other control data). The data is transferred + * as-is and must be properly framed and checksummed as appropriate + * by userspace. Frames are either sent whole or not at all as this + * avoids pain user side. + */ + +static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr) +{ + int space = tty_write_room(tty); + if (space >= nr) + return tty->ops->write(tty, buf, nr); + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + return -ENOBUFS; +} + +/** + * gsmld_poll - poll method for N_GSM0710 + * @tty: terminal device + * @file: file accessing it + * @wait: poll table + * + * Called when the line discipline is asked to poll() for data or + * for special events. This code is not serialized with respect to + * other events save open/close. + * + * This code must be sure never to sleep through a hangup. + * Called without the kernel lock held - fine + */ + +static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, + poll_table *wait) +{ + unsigned int mask = 0; + struct gsm_mux *gsm = tty->disc_data; + + poll_wait(file, &tty->read_wait, wait); + poll_wait(file, &tty->write_wait, wait); + if (tty_hung_up_p(file)) + mask |= POLLHUP; + if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) + mask |= POLLOUT | POLLWRNORM; + if (gsm->dead) + mask |= POLLHUP; + return mask; +} + +static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, + struct gsm_config *c) +{ + int need_close = 0; + int need_restart = 0; + + /* Stuff we don't support yet - UI or I frame transport, windowing */ + if ((c->adaption !=1 && c->adaption != 2) || c->k) + return -EOPNOTSUPP; + /* Check the MRU/MTU range looks sane */ + if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) + return -EINVAL; + if (c->n2 < 3) + return -EINVAL; + if (c->encapsulation > 1) /* Basic, advanced, no I */ + return -EINVAL; + if (c->initiator > 1) + return -EINVAL; + if (c->i == 0 || c->i > 2) /* UIH and UI only */ + return -EINVAL; + /* + * See what is needed for reconfiguration + */ + + /* Timing fields */ + if (c->t1 != 0 && c->t1 != gsm->t1) + need_restart = 1; + if (c->t2 != 0 && c->t2 != gsm->t2) + need_restart = 1; + if (c->encapsulation != gsm->encoding) + need_restart = 1; + if (c->adaption != gsm->adaption) + need_restart = 1; + /* Requires care */ + if (c->initiator != gsm->initiator) + need_close = 1; + if (c->mru != gsm->mru) + need_restart = 1; + if (c->mtu != gsm->mtu) + need_restart = 1; + + /* + * Close down what is needed, restart and initiate the new + * configuration + */ + + if (need_close || need_restart) { + gsm_dlci_begin_close(gsm->dlci[0]); + /* This will timeout if the link is down due to N2 expiring */ + wait_event_interruptible(gsm->event, + gsm->dlci[0]->state == DLCI_CLOSED); + if (signal_pending(current)) + return -EINTR; + } + if (need_restart) + gsm_cleanup_mux(gsm); + + gsm->initiator = c->initiator; + gsm->mru = c->mru; + gsm->encoding = c->encapsulation; + gsm->adaption = c->adaption; + + if (c->i == 1) + gsm->ftype = UIH; + else if (c->i == 2) + gsm->ftype = UI; + + if (c->t1) + gsm->t1 = c->t1; + if (c->t2) + gsm->t2 = c->t2; + + /* FIXME: We need to separate activation/deactivation from adding + and removing from the mux array */ + if (need_restart) + gsm_activate_mux(gsm); + if (gsm->initiator && need_close) + gsm_dlci_begin_open(gsm->dlci[0]); + return 0; +} + +static int gsmld_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct gsm_config c; + struct gsm_mux *gsm = tty->disc_data; + + switch (cmd) { + case GSMIOC_GETCONF: + memset(&c, 0, sizeof(c)); + c.adaption = gsm->adaption; + c.encapsulation = gsm->encoding; + c.initiator = gsm->initiator; + c.t1 = gsm->t1; + c.t2 = gsm->t2; + c.t3 = 0; /* Not supported */ + c.n2 = gsm->n2; + if (gsm->ftype == UIH) + c.i = 1; + else + c.i = 2; + printk("Ftype %d i %d\n", gsm->ftype, c.i); + c.mru = gsm->mru; + c.mtu = gsm->mtu; + c.k = 0; + if (copy_to_user((void *)arg, &c, sizeof(c))) + return -EFAULT; + return 0; + case GSMIOC_SETCONF: + if (copy_from_user(&c, (void *)arg, sizeof(c))) + return -EFAULT; + return gsmld_config(tty, gsm, &c); + default: + return n_tty_ioctl_helper(tty, file, cmd, arg); + } +} + + +/* Line discipline for real tty */ +struct tty_ldisc_ops tty_ldisc_packet = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "n_gsm", + .open = gsmld_open, + .close = gsmld_close, + .flush_buffer = gsmld_flush_buffer, + .chars_in_buffer = gsmld_chars_in_buffer, + .read = gsmld_read, + .write = gsmld_write, + .ioctl = gsmld_ioctl, + .poll = gsmld_poll, + .receive_buf = gsmld_receive_buf, + .write_wakeup = gsmld_write_wakeup +}; + +/* + * Virtual tty side + */ + +#define TX_SIZE 512 + +static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) +{ + u8 modembits[5]; + struct gsm_control *ctrl; + int len = 2; + + if (brk) + len++; + + modembits[0] = len << 1 | EA; /* Data bytes */ + modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ + modembits[2] = gsm_encode_modem(dlci) << 1 | EA; + if (brk) + modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ + ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); + if (ctrl == NULL) + return -ENOMEM; + return gsm_control_wait(dlci->gsm, ctrl); +} + +static int gsm_carrier_raised(struct tty_port *port) +{ + struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); + /* Not yet open so no carrier info */ + if (dlci->state != DLCI_OPEN) + return 0; + if (debug & 2) + return 1; + return dlci->modem_rx & TIOCM_CD; +} + +static void gsm_dtr_rts(struct tty_port *port, int onoff) +{ + struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); + unsigned int modem_tx = dlci->modem_tx; + if (onoff) + modem_tx |= TIOCM_DTR | TIOCM_RTS; + else + modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); + if (modem_tx != dlci->modem_tx) { + dlci->modem_tx = modem_tx; + gsmtty_modem_update(dlci, 0); + } +} + +static const struct tty_port_operations gsm_port_ops = { + .carrier_raised = gsm_carrier_raised, + .dtr_rts = gsm_dtr_rts, +}; + + +static int gsmtty_open(struct tty_struct *tty, struct file *filp) +{ + struct gsm_mux *gsm; + struct gsm_dlci *dlci; + struct tty_port *port; + unsigned int line = tty->index; + unsigned int mux = line >> 6; + + line = line & 0x3F; + + if (mux >= MAX_MUX) + return -ENXIO; + /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ + if (gsm_mux[mux] == NULL) + return -EUNATCH; + if (line == 0 || line > 61) /* 62/63 reserved */ + return -ECHRNG; + gsm = gsm_mux[mux]; + if (gsm->dead) + return -EL2HLT; + dlci = gsm->dlci[line]; + if (dlci == NULL) + dlci = gsm_dlci_alloc(gsm, line); + if (dlci == NULL) + return -ENOMEM; + port = &dlci->port; + port->count++; + tty->driver_data = dlci; + tty_port_tty_set(port, tty); + + dlci->modem_rx = 0; + /* We could in theory open and close before we wait - eg if we get + a DM straight back. This is ok as that will have caused a hangup */ + set_bit(ASYNCB_INITIALIZED, &port->flags); + /* Start sending off SABM messages */ + gsm_dlci_begin_open(dlci); + /* And wait for virtual carrier */ + return tty_port_block_til_ready(port, tty, filp); +} + +static void gsmtty_close(struct tty_struct *tty, struct file *filp) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (dlci == NULL) + return; + if (tty_port_close_start(&dlci->port, tty, filp) == 0) + return; + gsm_dlci_begin_close(dlci); + tty_port_close_end(&dlci->port, tty); + tty_port_tty_set(&dlci->port, NULL); +} + +static void gsmtty_hangup(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + tty_port_hangup(&dlci->port); + gsm_dlci_begin_close(dlci); +} + +static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, + int len) +{ + struct gsm_dlci *dlci = tty->driver_data; + /* Stuff the bytes into the fifo queue */ + int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); + /* Need to kick the channel */ + gsm_dlci_data_kick(dlci); + return sent; +} + +static int gsmtty_write_room(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + return TX_SIZE - kfifo_len(dlci->fifo); +} + +static int gsmtty_chars_in_buffer(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + return kfifo_len(dlci->fifo); +} + +static void gsmtty_flush_buffer(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + /* Caution needed: If we implement reliable transport classes + then the data being transmitted can't simply be junked once + it has first hit the stack. Until then we can just blow it + away */ + kfifo_reset(dlci->fifo); + /* Need to unhook this DLCI from the transmit queue logic */ +} + +static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) +{ + /* The FIFO handles the queue so the kernel will do the right + thing waiting on chars_in_buffer before calling us. No work + to do here */ +} + +static int gsmtty_tiocmget(struct tty_struct *tty, struct file *filp) +{ + struct gsm_dlci *dlci = tty->driver_data; + return dlci->modem_rx; +} + +static int gsmtty_tiocmset(struct tty_struct *tty, struct file *filp, + unsigned int set, unsigned int clear) +{ + struct gsm_dlci *dlci = tty->driver_data; + unsigned int modem_tx = dlci->modem_tx; + + modem_tx &= clear; + modem_tx |= set; + + if (modem_tx != dlci->modem_tx) { + dlci->modem_tx = modem_tx; + return gsmtty_modem_update(dlci, 0); + } + return 0; +} + + +static int gsmtty_ioctl(struct tty_struct *tty, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + return -ENOIOCTLCMD; +} + +static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) +{ + /* For the moment its fixed. In actual fact the speed information + for the virtual channel can be propogated in both directions by + the RPN control message. This however rapidly gets nasty as we + then have to remap modem signals each way according to whether + our virtual cable is null modem etc .. */ + tty_termios_copy_hw(tty->termios, old); +} + +static void gsmtty_throttle(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (tty->termios->c_cflag & CRTSCTS) + dlci->modem_tx &= ~TIOCM_DTR; + dlci->throttled = 1; + /* Send an MSC with DTR cleared */ + gsmtty_modem_update(dlci, 0); +} + +static void gsmtty_unthrottle(struct tty_struct *tty) +{ + struct gsm_dlci *dlci = tty->driver_data; + if (tty->termios->c_cflag & CRTSCTS) + dlci->modem_tx |= TIOCM_DTR; + dlci->throttled = 0; + /* Send an MSC with DTR set */ + gsmtty_modem_update(dlci, 0); +} + +static int gsmtty_break_ctl(struct tty_struct *tty, int state) +{ + struct gsm_dlci *dlci = tty->driver_data; + int encode = 0; /* Off */ + + if (state == -1) /* "On indefinitely" - we can't encode this + properly */ + encode = 0x0F; + else if (state > 0) { + encode = state / 200; /* mS to encoding */ + if (encode > 0x0F) + encode = 0x0F; /* Best effort */ + } + return gsmtty_modem_update(dlci, encode); +} + +static struct tty_driver *gsm_tty_driver; + +/* Virtual ttys for the demux */ +static const struct tty_operations gsmtty_ops = { + .open = gsmtty_open, + .close = gsmtty_close, + .write = gsmtty_write, + .write_room = gsmtty_write_room, + .chars_in_buffer = gsmtty_chars_in_buffer, + .flush_buffer = gsmtty_flush_buffer, + .ioctl = gsmtty_ioctl, + .throttle = gsmtty_throttle, + .unthrottle = gsmtty_unthrottle, + .set_termios = gsmtty_set_termios, + .hangup = gsmtty_hangup, + .wait_until_sent = gsmtty_wait_until_sent, + .tiocmget = gsmtty_tiocmget, + .tiocmset = gsmtty_tiocmset, + .break_ctl = gsmtty_break_ctl, +}; + + + +static int __init gsm_init(void) +{ + /* Fill in our line protocol discipline, and register it */ + int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); + if (status != 0) { + printk(KERN_ERR "n_gsm: can't register line discipline (err = %d)\n", status); + return status; + } + + gsm_tty_driver = alloc_tty_driver(256); + if (!gsm_tty_driver) { + tty_unregister_ldisc(N_GSM0710); + printk(KERN_ERR "gsm_init: tty allocation failed.\n"); + return -EINVAL; + } + gsm_tty_driver->owner = THIS_MODULE; + gsm_tty_driver->driver_name = "gsmtty"; + gsm_tty_driver->name = "gsmtty"; + gsm_tty_driver->major = 0; /* Dynamic */ + gsm_tty_driver->minor_start = 0; + gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; + gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; + gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV + | TTY_DRIVER_HARDWARE_BREAK; + gsm_tty_driver->init_termios = tty_std_termios; + /* Fixme */ + gsm_tty_driver->init_termios.c_lflag &= ~ECHO; + tty_set_operations(gsm_tty_driver, &gsmtty_ops); + + spin_lock_init(&gsm_mux_lock); + + if (tty_register_driver(gsm_tty_driver)) { + put_tty_driver(gsm_tty_driver); + tty_unregister_ldisc(N_GSM0710); + printk(KERN_ERR "gsm_init: tty registration failed.\n"); + return -EBUSY; + } + printk(KERN_INFO "gsm_init: loaded as %d,%d.\n", gsm_tty_driver->major, gsm_tty_driver->minor_start); + return 0; +} + +static void __exit gsm_exit(void) +{ + int status = tty_unregister_ldisc(N_GSM0710); + if (status != 0) + printk(KERN_ERR "n_gsm: can't unregister line discipline (err = %d)\n", status); + tty_unregister_driver(gsm_tty_driver); + put_tty_driver(gsm_tty_driver); + printk(KERN_INFO "gsm_init: unloaded.\n"); +} + +module_init(gsm_init); +module_exit(gsm_exit); + + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_LDISC(N_GSM0710); diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c new file mode 100644 index 00000000000..47d32281032 --- /dev/null +++ b/drivers/tty/n_hdlc.c @@ -0,0 +1,1007 @@ +/* generic HDLC line discipline for Linux + * + * Written by Paul Fulghum paulkf@microgate.com + * for Microgate Corporation + * + * Microgate and SyncLink are registered trademarks of Microgate Corporation + * + * Adapted from ppp.c, written by Michael Callahan <callahan@maths.ox.ac.uk>, + * Al Longyear <longyear@netcom.com>, + * Paul Mackerras <Paul.Mackerras@cs.anu.edu.au> + * + * Original release 01/11/99 + * + * This code is released under the GNU General Public License (GPL) + * + * This module implements the tty line discipline N_HDLC for use with + * tty device drivers that support bit-synchronous HDLC communications. + * + * All HDLC data is frame oriented which means: + * + * 1. tty write calls represent one complete transmit frame of data + * The device driver should accept the complete frame or none of + * the frame (busy) in the write method. Each write call should have + * a byte count in the range of 2-65535 bytes (2 is min HDLC frame + * with 1 addr byte and 1 ctrl byte). The max byte count of 65535 + * should include any crc bytes required. For example, when using + * CCITT CRC32, 4 crc bytes are required, so the maximum size frame + * the application may transmit is limited to 65531 bytes. For CCITT + * CRC16, the maximum application frame size would be 65533. + * + * + * 2. receive callbacks from the device driver represents + * one received frame. The device driver should bypass + * the tty flip buffer and call the line discipline receive + * callback directly to avoid fragmenting or concatenating + * multiple frames into a single receive callback. + * + * The HDLC line discipline queues the receive frames in separate + * buffers so complete receive frames can be returned by the + * tty read calls. + * + * 3. tty read calls returns an entire frame of data or nothing. + * + * 4. all send and receive data is considered raw. No processing + * or translation is performed by the line discipline, regardless + * of the tty flags + * + * 5. When line discipline is queried for the amount of receive + * data available (FIOC), 0 is returned if no data available, + * otherwise the count of the next available frame is returned. + * (instead of the sum of all received frame counts). + * + * These conventions allow the standard tty programming interface + * to be used for synchronous HDLC applications when used with + * this line discipline (or another line discipline that is frame + * oriented such as N_PPP). + * + * The SyncLink driver (synclink.c) implements both asynchronous + * (using standard line discipline N_TTY) and synchronous HDLC + * (using N_HDLC) communications, with the latter using the above + * conventions. + * + * This implementation is very basic and does not maintain + * any statistics. The main point is to enforce the raw data + * and frame orientation of HDLC communications. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#define HDLC_MAGIC 0x239e + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/fcntl.h> +#include <linux/interrupt.h> +#include <linux/ptrace.h> + +#undef VERSION +#define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch)) + +#include <linux/poll.h> +#include <linux/in.h> +#include <linux/ioctl.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/errno.h> +#include <linux/smp_lock.h> +#include <linux/string.h> /* used in new tty drivers */ +#include <linux/signal.h> /* used in new tty drivers */ +#include <linux/if.h> +#include <linux/bitops.h> + +#include <asm/system.h> +#include <asm/termios.h> +#include <asm/uaccess.h> + +/* + * Buffers for individual HDLC frames + */ +#define MAX_HDLC_FRAME_SIZE 65535 +#define DEFAULT_RX_BUF_COUNT 10 +#define MAX_RX_BUF_COUNT 60 +#define DEFAULT_TX_BUF_COUNT 3 + +struct n_hdlc_buf { + struct n_hdlc_buf *link; + int count; + char buf[1]; +}; + +#define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe) + +struct n_hdlc_buf_list { + struct n_hdlc_buf *head; + struct n_hdlc_buf *tail; + int count; + spinlock_t spinlock; +}; + +/** + * struct n_hdlc - per device instance data structure + * @magic - magic value for structure + * @flags - miscellaneous control flags + * @tty - ptr to TTY structure + * @backup_tty - TTY to use if tty gets closed + * @tbusy - reentrancy flag for tx wakeup code + * @woke_up - FIXME: describe this field + * @tbuf - currently transmitting tx buffer + * @tx_buf_list - list of pending transmit frame buffers + * @rx_buf_list - list of received frame buffers + * @tx_free_buf_list - list unused transmit frame buffers + * @rx_free_buf_list - list unused received frame buffers + */ +struct n_hdlc { + int magic; + __u32 flags; + struct tty_struct *tty; + struct tty_struct *backup_tty; + int tbusy; + int woke_up; + struct n_hdlc_buf *tbuf; + struct n_hdlc_buf_list tx_buf_list; + struct n_hdlc_buf_list rx_buf_list; + struct n_hdlc_buf_list tx_free_buf_list; + struct n_hdlc_buf_list rx_free_buf_list; +}; + +/* + * HDLC buffer list manipulation functions + */ +static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list); +static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, + struct n_hdlc_buf *buf); +static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list); + +/* Local functions */ + +static struct n_hdlc *n_hdlc_alloc (void); + +/* debug level can be set by insmod for debugging purposes */ +#define DEBUG_LEVEL_INFO 1 +static int debuglevel; + +/* max frame size for memory allocations */ +static int maxframe = 4096; + +/* TTY callbacks */ + +static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, + __u8 __user *buf, size_t nr); +static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr); +static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg); +static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, + poll_table *wait); +static int n_hdlc_tty_open(struct tty_struct *tty); +static void n_hdlc_tty_close(struct tty_struct *tty); +static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp, + char *fp, int count); +static void n_hdlc_tty_wakeup(struct tty_struct *tty); + +#define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f))) + +#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data)) +#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty) + +static void flush_rx_queue(struct tty_struct *tty) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc(tty); + struct n_hdlc_buf *buf; + + while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list))) + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf); +} + +static void flush_tx_queue(struct tty_struct *tty) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc(tty); + struct n_hdlc_buf *buf; + unsigned long flags; + + while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list))) + n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf); + spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); + if (n_hdlc->tbuf) { + n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf); + n_hdlc->tbuf = NULL; + } + spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); +} + +static struct tty_ldisc_ops n_hdlc_ldisc = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "hdlc", + .open = n_hdlc_tty_open, + .close = n_hdlc_tty_close, + .read = n_hdlc_tty_read, + .write = n_hdlc_tty_write, + .ioctl = n_hdlc_tty_ioctl, + .poll = n_hdlc_tty_poll, + .receive_buf = n_hdlc_tty_receive, + .write_wakeup = n_hdlc_tty_wakeup, + .flush_buffer = flush_rx_queue, +}; + +/** + * n_hdlc_release - release an n_hdlc per device line discipline info structure + * @n_hdlc - per device line discipline info structure + */ +static void n_hdlc_release(struct n_hdlc *n_hdlc) +{ + struct tty_struct *tty = n_hdlc2tty (n_hdlc); + struct n_hdlc_buf *buf; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__); + + /* Ensure that the n_hdlcd process is not hanging on select()/poll() */ + wake_up_interruptible (&tty->read_wait); + wake_up_interruptible (&tty->write_wait); + + if (tty->disc_data == n_hdlc) + tty->disc_data = NULL; /* Break the tty->n_hdlc link */ + + /* Release transmit and receive buffers */ + for(;;) { + buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list); + if (buf) { + kfree(buf); + } else + break; + } + for(;;) { + buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); + if (buf) { + kfree(buf); + } else + break; + } + for(;;) { + buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); + if (buf) { + kfree(buf); + } else + break; + } + for(;;) { + buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); + if (buf) { + kfree(buf); + } else + break; + } + kfree(n_hdlc->tbuf); + kfree(n_hdlc); + +} /* end of n_hdlc_release() */ + +/** + * n_hdlc_tty_close - line discipline close + * @tty - pointer to tty info structure + * + * Called when the line discipline is changed to something + * else, the tty is closed, or the tty detects a hangup. + */ +static void n_hdlc_tty_close(struct tty_struct *tty) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_close() called\n",__FILE__,__LINE__); + + if (n_hdlc != NULL) { + if (n_hdlc->magic != HDLC_MAGIC) { + printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n"); + return; + } +#if defined(TTY_NO_WRITE_SPLIT) + clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags); +#endif + tty->disc_data = NULL; + if (tty == n_hdlc->backup_tty) + n_hdlc->backup_tty = NULL; + if (tty != n_hdlc->tty) + return; + if (n_hdlc->backup_tty) { + n_hdlc->tty = n_hdlc->backup_tty; + } else { + n_hdlc_release (n_hdlc); + } + } + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_close() success\n",__FILE__,__LINE__); + +} /* end of n_hdlc_tty_close() */ + +/** + * n_hdlc_tty_open - called when line discipline changed to n_hdlc + * @tty - pointer to tty info structure + * + * Returns 0 if success, otherwise error code + */ +static int n_hdlc_tty_open (struct tty_struct *tty) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n", + __FILE__,__LINE__, + tty->name); + + /* There should not be an existing table for this slot. */ + if (n_hdlc) { + printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" ); + return -EEXIST; + } + + n_hdlc = n_hdlc_alloc(); + if (!n_hdlc) { + printk (KERN_ERR "n_hdlc_alloc failed\n"); + return -ENFILE; + } + + tty->disc_data = n_hdlc; + n_hdlc->tty = tty; + tty->receive_room = 65536; + +#if defined(TTY_NO_WRITE_SPLIT) + /* change tty_io write() to not split large writes into 8K chunks */ + set_bit(TTY_NO_WRITE_SPLIT,&tty->flags); +#endif + + /* flush receive data from driver */ + tty_driver_flush_buffer(tty); + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__); + + return 0; + +} /* end of n_tty_hdlc_open() */ + +/** + * n_hdlc_send_frames - send frames on pending send buffer list + * @n_hdlc - pointer to ldisc instance data + * @tty - pointer to tty instance data + * + * Send frames on pending send buffer list until the driver does not accept a + * frame (busy) this function is called after adding a frame to the send buffer + * list and by the tty wakeup callback. + */ +static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty) +{ + register int actual; + unsigned long flags; + struct n_hdlc_buf *tbuf; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__); + check_again: + + spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); + if (n_hdlc->tbusy) { + n_hdlc->woke_up = 1; + spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); + return; + } + n_hdlc->tbusy = 1; + n_hdlc->woke_up = 0; + spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); + + /* get current transmit buffer or get new transmit */ + /* buffer from list of pending transmit buffers */ + + tbuf = n_hdlc->tbuf; + if (!tbuf) + tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); + + while (tbuf) { + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)sending frame %p, count=%d\n", + __FILE__,__LINE__,tbuf,tbuf->count); + + /* Send the next block of data to device */ + tty->flags |= (1 << TTY_DO_WRITE_WAKEUP); + actual = tty->ops->write(tty, tbuf->buf, tbuf->count); + + /* rollback was possible and has been done */ + if (actual == -ERESTARTSYS) { + n_hdlc->tbuf = tbuf; + break; + } + /* if transmit error, throw frame away by */ + /* pretending it was accepted by driver */ + if (actual < 0) + actual = tbuf->count; + + if (actual == tbuf->count) { + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)frame %p completed\n", + __FILE__,__LINE__,tbuf); + + /* free current transmit buffer */ + n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf); + + /* this tx buffer is done */ + n_hdlc->tbuf = NULL; + + /* wait up sleeping writers */ + wake_up_interruptible(&tty->write_wait); + + /* get next pending transmit buffer */ + tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); + } else { + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)frame %p pending\n", + __FILE__,__LINE__,tbuf); + + /* buffer not accepted by driver */ + /* set this buffer as pending buffer */ + n_hdlc->tbuf = tbuf; + break; + } + } + + if (!tbuf) + tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); + + /* Clear the re-entry flag */ + spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); + n_hdlc->tbusy = 0; + spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); + + if (n_hdlc->woke_up) + goto check_again; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__); + +} /* end of n_hdlc_send_frames() */ + +/** + * n_hdlc_tty_wakeup - Callback for transmit wakeup + * @tty - pointer to associated tty instance data + * + * Called when low level device driver can accept more send data. + */ +static void n_hdlc_tty_wakeup(struct tty_struct *tty) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc(tty); + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_wakeup() called\n",__FILE__,__LINE__); + + if (!n_hdlc) + return; + + if (tty != n_hdlc->tty) { + tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); + return; + } + + n_hdlc_send_frames (n_hdlc, tty); + +} /* end of n_hdlc_tty_wakeup() */ + +/** + * n_hdlc_tty_receive - Called by tty driver when receive data is available + * @tty - pointer to tty instance data + * @data - pointer to received data + * @flags - pointer to flags for data + * @count - count of received data in bytes + * + * Called by tty low level driver when receive data is available. Data is + * interpreted as one HDLC frame. + */ +static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, + char *flags, int count) +{ + register struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + register struct n_hdlc_buf *buf; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_receive() called count=%d\n", + __FILE__,__LINE__, count); + + /* This can happen if stuff comes in on the backup tty */ + if (!n_hdlc || tty != n_hdlc->tty) + return; + + /* verify line is using HDLC discipline */ + if (n_hdlc->magic != HDLC_MAGIC) { + printk("%s(%d) line not using HDLC discipline\n", + __FILE__,__LINE__); + return; + } + + if ( count>maxframe ) { + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d) rx count>maxframesize, data discarded\n", + __FILE__,__LINE__); + return; + } + + /* get a free HDLC buffer */ + buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list); + if (!buf) { + /* no buffers in free list, attempt to allocate another rx buffer */ + /* unless the maximum count has been reached */ + if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT) + buf = kmalloc(N_HDLC_BUF_SIZE, GFP_ATOMIC); + } + + if (!buf) { + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d) no more rx buffers, data discarded\n", + __FILE__,__LINE__); + return; + } + + /* copy received data to HDLC buffer */ + memcpy(buf->buf,data,count); + buf->count=count; + + /* add HDLC buffer to list of received frames */ + n_hdlc_buf_put(&n_hdlc->rx_buf_list, buf); + + /* wake up any blocked reads and perform async signalling */ + wake_up_interruptible (&tty->read_wait); + if (n_hdlc->tty->fasync != NULL) + kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN); + +} /* end of n_hdlc_tty_receive() */ + +/** + * n_hdlc_tty_read - Called to retrieve one frame of data (if available) + * @tty - pointer to tty instance data + * @file - pointer to open file object + * @buf - pointer to returned data buffer + * @nr - size of returned data buffer + * + * Returns the number of bytes returned or error code. + */ +static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, + __u8 __user *buf, size_t nr) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc(tty); + int ret; + struct n_hdlc_buf *rbuf; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__); + + /* Validate the pointers */ + if (!n_hdlc) + return -EIO; + + /* verify user access to buffer */ + if (!access_ok(VERIFY_WRITE, buf, nr)) { + printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user " + "buffer\n", __FILE__, __LINE__); + return -EFAULT; + } + + tty_lock(); + + for (;;) { + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + tty_unlock(); + return -EIO; + } + + n_hdlc = tty2n_hdlc (tty); + if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || + tty != n_hdlc->tty) { + tty_unlock(); + return 0; + } + + rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); + if (rbuf) + break; + + /* no data */ + if (file->f_flags & O_NONBLOCK) { + tty_unlock(); + return -EAGAIN; + } + + interruptible_sleep_on (&tty->read_wait); + if (signal_pending(current)) { + tty_unlock(); + return -EINTR; + } + } + + if (rbuf->count > nr) + /* frame too large for caller's buffer (discard frame) */ + ret = -EOVERFLOW; + else { + /* Copy the data to the caller's buffer */ + if (copy_to_user(buf, rbuf->buf, rbuf->count)) + ret = -EFAULT; + else + ret = rbuf->count; + } + + /* return HDLC buffer to free list unless the free list */ + /* count has exceeded the default value, in which case the */ + /* buffer is freed back to the OS to conserve memory */ + if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT) + kfree(rbuf); + else + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf); + tty_unlock(); + return ret; + +} /* end of n_hdlc_tty_read() */ + +/** + * n_hdlc_tty_write - write a single frame of data to device + * @tty - pointer to associated tty device instance data + * @file - pointer to file object data + * @data - pointer to transmit data (one frame) + * @count - size of transmit frame in bytes + * + * Returns the number of bytes written (or error code). + */ +static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, + const unsigned char *data, size_t count) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + int error = 0; + DECLARE_WAITQUEUE(wait, current); + struct n_hdlc_buf *tbuf; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_write() called count=%Zd\n", + __FILE__,__LINE__,count); + + /* Verify pointers */ + if (!n_hdlc) + return -EIO; + + if (n_hdlc->magic != HDLC_MAGIC) + return -EIO; + + /* verify frame size */ + if (count > maxframe ) { + if (debuglevel & DEBUG_LEVEL_INFO) + printk (KERN_WARNING + "n_hdlc_tty_write: truncating user packet " + "from %lu to %d\n", (unsigned long) count, + maxframe ); + count = maxframe; + } + + tty_lock(); + + add_wait_queue(&tty->write_wait, &wait); + set_current_state(TASK_INTERRUPTIBLE); + + /* Allocate transmit buffer */ + /* sleep until transmit buffer available */ + while (!(tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list))) { + if (file->f_flags & O_NONBLOCK) { + error = -EAGAIN; + break; + } + schedule(); + + n_hdlc = tty2n_hdlc (tty); + if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || + tty != n_hdlc->tty) { + printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc); + error = -EIO; + break; + } + + if (signal_pending(current)) { + error = -EINTR; + break; + } + } + + set_current_state(TASK_RUNNING); + remove_wait_queue(&tty->write_wait, &wait); + + if (!error) { + /* Retrieve the user's buffer */ + memcpy(tbuf->buf, data, count); + + /* Send the data */ + tbuf->count = error = count; + n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); + n_hdlc_send_frames(n_hdlc,tty); + } + tty_unlock(); + return error; + +} /* end of n_hdlc_tty_write() */ + +/** + * n_hdlc_tty_ioctl - process IOCTL system call for the tty device. + * @tty - pointer to tty instance data + * @file - pointer to open file object for device + * @cmd - IOCTL command code + * @arg - argument for IOCTL call (cmd dependent) + * + * Returns command dependent result. + */ +static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + int error = 0; + int count; + unsigned long flags; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_ioctl() called %d\n", + __FILE__,__LINE__,cmd); + + /* Verify the status of the device */ + if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) + return -EBADF; + + switch (cmd) { + case FIONREAD: + /* report count of read data available */ + /* in next available frame (if any) */ + spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags); + if (n_hdlc->rx_buf_list.head) + count = n_hdlc->rx_buf_list.head->count; + else + count = 0; + spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags); + error = put_user(count, (int __user *)arg); + break; + + case TIOCOUTQ: + /* get the pending tx byte count in the driver */ + count = tty_chars_in_buffer(tty); + /* add size of next output frame in queue */ + spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags); + if (n_hdlc->tx_buf_list.head) + count += n_hdlc->tx_buf_list.head->count; + spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags); + error = put_user(count, (int __user *)arg); + break; + + case TCFLSH: + switch (arg) { + case TCIOFLUSH: + case TCOFLUSH: + flush_tx_queue(tty); + } + /* fall through to default */ + + default: + error = n_tty_ioctl_helper(tty, file, cmd, arg); + break; + } + return error; + +} /* end of n_hdlc_tty_ioctl() */ + +/** + * n_hdlc_tty_poll - TTY callback for poll system call + * @tty - pointer to tty instance data + * @filp - pointer to open file object for device + * @poll_table - wait queue for operations + * + * Determine which operations (read/write) will not block and return info + * to caller. + * Returns a bit mask containing info on which ops will not block. + */ +static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, + poll_table *wait) +{ + struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + unsigned int mask = 0; + + if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__); + + if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) { + /* queue current process into any wait queue that */ + /* may awaken in the future (read and write) */ + + poll_wait(filp, &tty->read_wait, wait); + poll_wait(filp, &tty->write_wait, wait); + + /* set bits for operations that won't block */ + if (n_hdlc->rx_buf_list.head) + mask |= POLLIN | POLLRDNORM; /* readable */ + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) + mask |= POLLHUP; + if (tty_hung_up_p(filp)) + mask |= POLLHUP; + if (!tty_is_writelocked(tty) && + n_hdlc->tx_free_buf_list.head) + mask |= POLLOUT | POLLWRNORM; /* writable */ + } + return mask; +} /* end of n_hdlc_tty_poll() */ + +/** + * n_hdlc_alloc - allocate an n_hdlc instance data structure + * + * Returns a pointer to newly created structure if success, otherwise %NULL + */ +static struct n_hdlc *n_hdlc_alloc(void) +{ + struct n_hdlc_buf *buf; + int i; + struct n_hdlc *n_hdlc = kmalloc(sizeof(*n_hdlc), GFP_KERNEL); + + if (!n_hdlc) + return NULL; + + memset(n_hdlc, 0, sizeof(*n_hdlc)); + + n_hdlc_buf_list_init(&n_hdlc->rx_free_buf_list); + n_hdlc_buf_list_init(&n_hdlc->tx_free_buf_list); + n_hdlc_buf_list_init(&n_hdlc->rx_buf_list); + n_hdlc_buf_list_init(&n_hdlc->tx_buf_list); + + /* allocate free rx buffer list */ + for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) { + buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); + if (buf) + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf); + else if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i); + } + + /* allocate free tx buffer list */ + for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) { + buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); + if (buf) + n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf); + else if (debuglevel >= DEBUG_LEVEL_INFO) + printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i); + } + + /* Initialize the control block */ + n_hdlc->magic = HDLC_MAGIC; + n_hdlc->flags = 0; + + return n_hdlc; + +} /* end of n_hdlc_alloc() */ + +/** + * n_hdlc_buf_list_init - initialize specified HDLC buffer list + * @list - pointer to buffer list + */ +static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list) +{ + memset(list, 0, sizeof(*list)); + spin_lock_init(&list->spinlock); +} /* end of n_hdlc_buf_list_init() */ + +/** + * n_hdlc_buf_put - add specified HDLC buffer to tail of specified list + * @list - pointer to buffer list + * @buf - pointer to buffer + */ +static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, + struct n_hdlc_buf *buf) +{ + unsigned long flags; + spin_lock_irqsave(&list->spinlock,flags); + + buf->link=NULL; + if (list->tail) + list->tail->link = buf; + else + list->head = buf; + list->tail = buf; + (list->count)++; + + spin_unlock_irqrestore(&list->spinlock,flags); + +} /* end of n_hdlc_buf_put() */ + +/** + * n_hdlc_buf_get - remove and return an HDLC buffer from list + * @list - pointer to HDLC buffer list + * + * Remove and return an HDLC buffer from the head of the specified HDLC buffer + * list. + * Returns a pointer to HDLC buffer if available, otherwise %NULL. + */ +static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list) +{ + unsigned long flags; + struct n_hdlc_buf *buf; + spin_lock_irqsave(&list->spinlock,flags); + + buf = list->head; + if (buf) { + list->head = buf->link; + (list->count)--; + } + if (!list->head) + list->tail = NULL; + + spin_unlock_irqrestore(&list->spinlock,flags); + return buf; + +} /* end of n_hdlc_buf_get() */ + +static char hdlc_banner[] __initdata = + KERN_INFO "HDLC line discipline maxframe=%u\n"; +static char hdlc_register_ok[] __initdata = + KERN_INFO "N_HDLC line discipline registered.\n"; +static char hdlc_register_fail[] __initdata = + KERN_ERR "error registering line discipline: %d\n"; +static char hdlc_init_fail[] __initdata = + KERN_INFO "N_HDLC: init failure %d\n"; + +static int __init n_hdlc_init(void) +{ + int status; + + /* range check maxframe arg */ + if (maxframe < 4096) + maxframe = 4096; + else if (maxframe > 65535) + maxframe = 65535; + + printk(hdlc_banner, maxframe); + + status = tty_register_ldisc(N_HDLC, &n_hdlc_ldisc); + if (!status) + printk(hdlc_register_ok); + else + printk(hdlc_register_fail, status); + + if (status) + printk(hdlc_init_fail, status); + return status; + +} /* end of init_module() */ + +static char hdlc_unregister_ok[] __exitdata = + KERN_INFO "N_HDLC: line discipline unregistered\n"; +static char hdlc_unregister_fail[] __exitdata = + KERN_ERR "N_HDLC: can't unregister line discipline (err = %d)\n"; + +static void __exit n_hdlc_exit(void) +{ + /* Release tty registration of line discipline */ + int status = tty_unregister_ldisc(N_HDLC); + + if (status) + printk(hdlc_unregister_fail, status); + else + printk(hdlc_unregister_ok); +} + +module_init(n_hdlc_init); +module_exit(n_hdlc_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Paul Fulghum paulkf@microgate.com"); +module_param(debuglevel, int, 0); +module_param(maxframe, int, 0); +MODULE_ALIAS_LDISC(N_HDLC); diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c new file mode 100644 index 00000000000..88dda0c45ee --- /dev/null +++ b/drivers/tty/n_r3964.c @@ -0,0 +1,1264 @@ +/* r3964 linediscipline for linux + * + * ----------------------------------------------------------- + * Copyright by + * Philips Automation Projects + * Kassel (Germany) + * ----------------------------------------------------------- + * This software may be used and distributed according to the terms of + * the GNU General Public License, incorporated herein by reference. + * + * Author: + * L. Haag + * + * $Log: n_r3964.c,v $ + * Revision 1.10 2001/03/18 13:02:24 dwmw2 + * Fix timer usage, use spinlocks properly. + * + * Revision 1.9 2001/03/18 12:52:14 dwmw2 + * Merge changes in 2.4.2 + * + * Revision 1.8 2000/03/23 14:14:54 dwmw2 + * Fix race in sleeping in r3964_read() + * + * Revision 1.7 1999/28/08 11:41:50 dwmw2 + * Port to 2.3 kernel + * + * Revision 1.6 1998/09/30 00:40:40 dwmw2 + * Fixed compilation on 2.0.x kernels + * Updated to newly registered tty-ldisc number 9 + * + * Revision 1.5 1998/09/04 21:57:36 dwmw2 + * Signal handling bug fixes, port to 2.1.x. + * + * Revision 1.4 1998/04/02 20:26:59 lhaag + * select, blocking, ... + * + * Revision 1.3 1998/02/12 18:58:43 root + * fixed some memory leaks + * calculation of checksum characters + * + * Revision 1.2 1998/02/07 13:03:34 root + * ioctl read_telegram + * + * Revision 1.1 1998/02/06 19:21:03 root + * Initial revision + * + * + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/fcntl.h> +#include <linux/interrupt.h> +#include <linux/ptrace.h> +#include <linux/ioport.h> +#include <linux/in.h> +#include <linux/slab.h> +#include <linux/smp_lock.h> +#include <linux/tty.h> +#include <linux/errno.h> +#include <linux/string.h> /* used in new tty drivers */ +#include <linux/signal.h> /* used in new tty drivers */ +#include <linux/ioctl.h> +#include <linux/n_r3964.h> +#include <linux/poll.h> +#include <linux/init.h> +#include <asm/uaccess.h> + +/*#define DEBUG_QUEUE*/ + +/* Log successful handshake and protocol operations */ +/*#define DEBUG_PROTO_S*/ + +/* Log handshake and protocol errors: */ +/*#define DEBUG_PROTO_E*/ + +/* Log Linediscipline operations (open, close, read, write...): */ +/*#define DEBUG_LDISC*/ + +/* Log module and memory operations (init, cleanup; kmalloc, kfree): */ +/*#define DEBUG_MODUL*/ + +/* Macro helpers for debug output: */ +#define TRACE(format, args...) printk("r3964: " format "\n" , ## args) + +#ifdef DEBUG_MODUL +#define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args) +#else +#define TRACE_M(fmt, arg...) do {} while (0) +#endif +#ifdef DEBUG_PROTO_S +#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args) +#else +#define TRACE_PS(fmt, arg...) do {} while (0) +#endif +#ifdef DEBUG_PROTO_E +#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args) +#else +#define TRACE_PE(fmt, arg...) do {} while (0) +#endif +#ifdef DEBUG_LDISC +#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args) +#else +#define TRACE_L(fmt, arg...) do {} while (0) +#endif +#ifdef DEBUG_QUEUE +#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args) +#else +#define TRACE_Q(fmt, arg...) do {} while (0) +#endif +static void add_tx_queue(struct r3964_info *, struct r3964_block_header *); +static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code); +static void put_char(struct r3964_info *pInfo, unsigned char ch); +static void trigger_transmit(struct r3964_info *pInfo); +static void retry_transmit(struct r3964_info *pInfo); +static void transmit_block(struct r3964_info *pInfo); +static void receive_char(struct r3964_info *pInfo, const unsigned char c); +static void receive_error(struct r3964_info *pInfo, const char flag); +static void on_timeout(unsigned long priv); +static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg); +static int read_telegram(struct r3964_info *pInfo, struct pid *pid, + unsigned char __user * buf); +static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg, + int error_code, struct r3964_block_header *pBlock); +static struct r3964_message *remove_msg(struct r3964_info *pInfo, + struct r3964_client_info *pClient); +static void remove_client_block(struct r3964_info *pInfo, + struct r3964_client_info *pClient); + +static int r3964_open(struct tty_struct *tty); +static void r3964_close(struct tty_struct *tty); +static ssize_t r3964_read(struct tty_struct *tty, struct file *file, + unsigned char __user * buf, size_t nr); +static ssize_t r3964_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr); +static int r3964_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg); +static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old); +static unsigned int r3964_poll(struct tty_struct *tty, struct file *file, + struct poll_table_struct *wait); +static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count); + +static struct tty_ldisc_ops tty_ldisc_N_R3964 = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "R3964", + .open = r3964_open, + .close = r3964_close, + .read = r3964_read, + .write = r3964_write, + .ioctl = r3964_ioctl, + .set_termios = r3964_set_termios, + .poll = r3964_poll, + .receive_buf = r3964_receive_buf, +}; + +static void dump_block(const unsigned char *block, unsigned int length) +{ + unsigned int i, j; + char linebuf[16 * 3 + 1]; + + for (i = 0; i < length; i += 16) { + for (j = 0; (j < 16) && (j + i < length); j++) { + sprintf(linebuf + 3 * j, "%02x ", block[i + j]); + } + linebuf[3 * j] = '\0'; + TRACE_PS("%s", linebuf); + } +} + +/************************************************************* + * Driver initialisation + *************************************************************/ + +/************************************************************* + * Module support routines + *************************************************************/ + +static void __exit r3964_exit(void) +{ + int status; + + TRACE_M("cleanup_module()"); + + status = tty_unregister_ldisc(N_R3964); + + if (status != 0) { + printk(KERN_ERR "r3964: error unregistering linediscipline: " + "%d\n", status); + } else { + TRACE_L("linediscipline successfully unregistered"); + } +} + +static int __init r3964_init(void) +{ + int status; + + printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n"); + + /* + * Register the tty line discipline + */ + + status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964); + if (status == 0) { + TRACE_L("line discipline %d registered", N_R3964); + TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags, + tty_ldisc_N_R3964.num); + TRACE_L("open=%p", tty_ldisc_N_R3964.open); + TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964); + } else { + printk(KERN_ERR "r3964: error registering line discipline: " + "%d\n", status); + } + return status; +} + +module_init(r3964_init); +module_exit(r3964_exit); + +/************************************************************* + * Protocol implementation routines + *************************************************************/ + +static void add_tx_queue(struct r3964_info *pInfo, + struct r3964_block_header *pHeader) +{ + unsigned long flags; + + spin_lock_irqsave(&pInfo->lock, flags); + + pHeader->next = NULL; + + if (pInfo->tx_last == NULL) { + pInfo->tx_first = pInfo->tx_last = pHeader; + } else { + pInfo->tx_last->next = pHeader; + pInfo->tx_last = pHeader; + } + + spin_unlock_irqrestore(&pInfo->lock, flags); + + TRACE_Q("add_tx_queue %p, length %d, tx_first = %p", + pHeader, pHeader->length, pInfo->tx_first); +} + +static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code) +{ + struct r3964_block_header *pHeader; + unsigned long flags; +#ifdef DEBUG_QUEUE + struct r3964_block_header *pDump; +#endif + + pHeader = pInfo->tx_first; + + if (pHeader == NULL) + return; + +#ifdef DEBUG_QUEUE + printk("r3964: remove_from_tx_queue: %p, length %u - ", + pHeader, pHeader->length); + for (pDump = pHeader; pDump; pDump = pDump->next) + printk("%p ", pDump); + printk("\n"); +#endif + + if (pHeader->owner) { + if (error_code) { + add_msg(pHeader->owner, R3964_MSG_ACK, 0, + error_code, NULL); + } else { + add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length, + error_code, NULL); + } + wake_up_interruptible(&pInfo->read_wait); + } + + spin_lock_irqsave(&pInfo->lock, flags); + + pInfo->tx_first = pHeader->next; + if (pInfo->tx_first == NULL) { + pInfo->tx_last = NULL; + } + + spin_unlock_irqrestore(&pInfo->lock, flags); + + kfree(pHeader); + TRACE_M("remove_from_tx_queue - kfree %p", pHeader); + + TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p", + pInfo->tx_first, pInfo->tx_last); +} + +static void add_rx_queue(struct r3964_info *pInfo, + struct r3964_block_header *pHeader) +{ + unsigned long flags; + + spin_lock_irqsave(&pInfo->lock, flags); + + pHeader->next = NULL; + + if (pInfo->rx_last == NULL) { + pInfo->rx_first = pInfo->rx_last = pHeader; + } else { + pInfo->rx_last->next = pHeader; + pInfo->rx_last = pHeader; + } + pInfo->blocks_in_rx_queue++; + + spin_unlock_irqrestore(&pInfo->lock, flags); + + TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d", + pHeader, pHeader->length, + pInfo->rx_first, pInfo->blocks_in_rx_queue); +} + +static void remove_from_rx_queue(struct r3964_info *pInfo, + struct r3964_block_header *pHeader) +{ + unsigned long flags; + struct r3964_block_header *pFind; + + if (pHeader == NULL) + return; + + TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d", + pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue); + TRACE_Q("remove_from_rx_queue: %p, length %u", + pHeader, pHeader->length); + + spin_lock_irqsave(&pInfo->lock, flags); + + if (pInfo->rx_first == pHeader) { + /* Remove the first block in the linked list: */ + pInfo->rx_first = pHeader->next; + + if (pInfo->rx_first == NULL) { + pInfo->rx_last = NULL; + } + pInfo->blocks_in_rx_queue--; + } else { + /* Find block to remove: */ + for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) { + if (pFind->next == pHeader) { + /* Got it. */ + pFind->next = pHeader->next; + pInfo->blocks_in_rx_queue--; + if (pFind->next == NULL) { + /* Oh, removed the last one! */ + pInfo->rx_last = pFind; + } + break; + } + } + } + + spin_unlock_irqrestore(&pInfo->lock, flags); + + kfree(pHeader); + TRACE_M("remove_from_rx_queue - kfree %p", pHeader); + + TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d", + pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue); +} + +static void put_char(struct r3964_info *pInfo, unsigned char ch) +{ + struct tty_struct *tty = pInfo->tty; + /* FIXME: put_char should not be called from an IRQ */ + tty_put_char(tty, ch); + pInfo->bcc ^= ch; +} + +static void flush(struct r3964_info *pInfo) +{ + struct tty_struct *tty = pInfo->tty; + + if (tty == NULL || tty->ops->flush_chars == NULL) + return; + tty->ops->flush_chars(tty); +} + +static void trigger_transmit(struct r3964_info *pInfo) +{ + unsigned long flags; + + spin_lock_irqsave(&pInfo->lock, flags); + + if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) { + pInfo->state = R3964_TX_REQUEST; + pInfo->nRetry = 0; + pInfo->flags &= ~R3964_ERROR; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ); + + spin_unlock_irqrestore(&pInfo->lock, flags); + + TRACE_PS("trigger_transmit - sent STX"); + + put_char(pInfo, STX); + flush(pInfo); + + pInfo->bcc = 0; + } else { + spin_unlock_irqrestore(&pInfo->lock, flags); + } +} + +static void retry_transmit(struct r3964_info *pInfo) +{ + if (pInfo->nRetry < R3964_MAX_RETRIES) { + TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry); + pInfo->bcc = 0; + put_char(pInfo, STX); + flush(pInfo); + pInfo->state = R3964_TX_REQUEST; + pInfo->nRetry++; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ); + } else { + TRACE_PE("transmission failed after %d retries", + R3964_MAX_RETRIES); + + remove_from_tx_queue(pInfo, R3964_TX_FAIL); + + put_char(pInfo, NAK); + flush(pInfo); + pInfo->state = R3964_IDLE; + + trigger_transmit(pInfo); + } +} + +static void transmit_block(struct r3964_info *pInfo) +{ + struct tty_struct *tty = pInfo->tty; + struct r3964_block_header *pBlock = pInfo->tx_first; + int room = 0; + + if (tty == NULL || pBlock == NULL) { + return; + } + + room = tty_write_room(tty); + + TRACE_PS("transmit_block %p, room %d, length %d", + pBlock, room, pBlock->length); + + while (pInfo->tx_position < pBlock->length) { + if (room < 2) + break; + + if (pBlock->data[pInfo->tx_position] == DLE) { + /* send additional DLE char: */ + put_char(pInfo, DLE); + } + put_char(pInfo, pBlock->data[pInfo->tx_position++]); + + room--; + } + + if ((pInfo->tx_position == pBlock->length) && (room >= 3)) { + put_char(pInfo, DLE); + put_char(pInfo, ETX); + if (pInfo->flags & R3964_BCC) { + put_char(pInfo, pInfo->bcc); + } + pInfo->state = R3964_WAIT_FOR_TX_ACK; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ); + } + flush(pInfo); +} + +static void on_receive_block(struct r3964_info *pInfo) +{ + unsigned int length; + struct r3964_client_info *pClient; + struct r3964_block_header *pBlock; + + length = pInfo->rx_position; + + /* compare byte checksum characters: */ + if (pInfo->flags & R3964_BCC) { + if (pInfo->bcc != pInfo->last_rx) { + TRACE_PE("checksum error - got %x but expected %x", + pInfo->last_rx, pInfo->bcc); + pInfo->flags |= R3964_CHECKSUM; + } + } + + /* check for errors (parity, overrun,...): */ + if (pInfo->flags & R3964_ERROR) { + TRACE_PE("on_receive_block - transmission failed error %x", + pInfo->flags & R3964_ERROR); + + put_char(pInfo, NAK); + flush(pInfo); + if (pInfo->nRetry < R3964_MAX_RETRIES) { + pInfo->state = R3964_WAIT_FOR_RX_REPEAT; + pInfo->nRetry++; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC); + } else { + TRACE_PE("on_receive_block - failed after max retries"); + pInfo->state = R3964_IDLE; + } + return; + } + + /* received block; submit DLE: */ + put_char(pInfo, DLE); + flush(pInfo); + del_timer_sync(&pInfo->tmr); + TRACE_PS(" rx success: got %d chars", length); + + /* prepare struct r3964_block_header: */ + pBlock = kmalloc(length + sizeof(struct r3964_block_header), + GFP_KERNEL); + TRACE_M("on_receive_block - kmalloc %p", pBlock); + + if (pBlock == NULL) + return; + + pBlock->length = length; + pBlock->data = ((unsigned char *)pBlock) + + sizeof(struct r3964_block_header); + pBlock->locks = 0; + pBlock->next = NULL; + pBlock->owner = NULL; + + memcpy(pBlock->data, pInfo->rx_buf, length); + + /* queue block into rx_queue: */ + add_rx_queue(pInfo, pBlock); + + /* notify attached client processes: */ + for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) { + if (pClient->sig_flags & R3964_SIG_DATA) { + add_msg(pClient, R3964_MSG_DATA, length, R3964_OK, + pBlock); + } + } + wake_up_interruptible(&pInfo->read_wait); + + pInfo->state = R3964_IDLE; + + trigger_transmit(pInfo); +} + +static void receive_char(struct r3964_info *pInfo, const unsigned char c) +{ + switch (pInfo->state) { + case R3964_TX_REQUEST: + if (c == DLE) { + TRACE_PS("TX_REQUEST - got DLE"); + + pInfo->state = R3964_TRANSMITTING; + pInfo->tx_position = 0; + + transmit_block(pInfo); + } else if (c == STX) { + if (pInfo->nRetry == 0) { + TRACE_PE("TX_REQUEST - init conflict"); + if (pInfo->priority == R3964_SLAVE) { + goto start_receiving; + } + } else { + TRACE_PE("TX_REQUEST - secondary init " + "conflict!? Switching to SLAVE mode " + "for next rx."); + goto start_receiving; + } + } else { + TRACE_PE("TX_REQUEST - char != DLE: %x", c); + retry_transmit(pInfo); + } + break; + case R3964_TRANSMITTING: + if (c == NAK) { + TRACE_PE("TRANSMITTING - got NAK"); + retry_transmit(pInfo); + } else { + TRACE_PE("TRANSMITTING - got invalid char"); + + pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ); + } + break; + case R3964_WAIT_FOR_TX_ACK: + if (c == DLE) { + TRACE_PS("WAIT_FOR_TX_ACK - got DLE"); + remove_from_tx_queue(pInfo, R3964_OK); + + pInfo->state = R3964_IDLE; + trigger_transmit(pInfo); + } else { + retry_transmit(pInfo); + } + break; + case R3964_WAIT_FOR_RX_REPEAT: + /* FALLTHROUGH */ + case R3964_IDLE: + if (c == STX) { + /* Prevent rx_queue from overflow: */ + if (pInfo->blocks_in_rx_queue >= + R3964_MAX_BLOCKS_IN_RX_QUEUE) { + TRACE_PE("IDLE - got STX but no space in " + "rx_queue!"); + pInfo->state = R3964_WAIT_FOR_RX_BUF; + mod_timer(&pInfo->tmr, + jiffies + R3964_TO_NO_BUF); + break; + } +start_receiving: + /* Ok, start receiving: */ + TRACE_PS("IDLE - got STX"); + pInfo->rx_position = 0; + pInfo->last_rx = 0; + pInfo->flags &= ~R3964_ERROR; + pInfo->state = R3964_RECEIVING; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ); + pInfo->nRetry = 0; + put_char(pInfo, DLE); + flush(pInfo); + pInfo->bcc = 0; + } + break; + case R3964_RECEIVING: + if (pInfo->rx_position < RX_BUF_SIZE) { + pInfo->bcc ^= c; + + if (c == DLE) { + if (pInfo->last_rx == DLE) { + pInfo->last_rx = 0; + goto char_to_buf; + } + pInfo->last_rx = DLE; + break; + } else if ((c == ETX) && (pInfo->last_rx == DLE)) { + if (pInfo->flags & R3964_BCC) { + pInfo->state = R3964_WAIT_FOR_BCC; + mod_timer(&pInfo->tmr, + jiffies + R3964_TO_ZVZ); + } else { + on_receive_block(pInfo); + } + } else { + pInfo->last_rx = c; +char_to_buf: + pInfo->rx_buf[pInfo->rx_position++] = c; + mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ); + } + } + /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */ + break; + case R3964_WAIT_FOR_BCC: + pInfo->last_rx = c; + on_receive_block(pInfo); + break; + } +} + +static void receive_error(struct r3964_info *pInfo, const char flag) +{ + switch (flag) { + case TTY_NORMAL: + break; + case TTY_BREAK: + TRACE_PE("received break"); + pInfo->flags |= R3964_BREAK; + break; + case TTY_PARITY: + TRACE_PE("parity error"); + pInfo->flags |= R3964_PARITY; + break; + case TTY_FRAME: + TRACE_PE("frame error"); + pInfo->flags |= R3964_FRAME; + break; + case TTY_OVERRUN: + TRACE_PE("frame overrun"); + pInfo->flags |= R3964_OVERRUN; + break; + default: + TRACE_PE("receive_error - unknown flag %d", flag); + pInfo->flags |= R3964_UNKNOWN; + break; + } +} + +static void on_timeout(unsigned long priv) +{ + struct r3964_info *pInfo = (void *)priv; + + switch (pInfo->state) { + case R3964_TX_REQUEST: + TRACE_PE("TX_REQUEST - timeout"); + retry_transmit(pInfo); + break; + case R3964_WAIT_ZVZ_BEFORE_TX_RETRY: + put_char(pInfo, NAK); + flush(pInfo); + retry_transmit(pInfo); + break; + case R3964_WAIT_FOR_TX_ACK: + TRACE_PE("WAIT_FOR_TX_ACK - timeout"); + retry_transmit(pInfo); + break; + case R3964_WAIT_FOR_RX_BUF: + TRACE_PE("WAIT_FOR_RX_BUF - timeout"); + put_char(pInfo, NAK); + flush(pInfo); + pInfo->state = R3964_IDLE; + break; + case R3964_RECEIVING: + TRACE_PE("RECEIVING - timeout after %d chars", + pInfo->rx_position); + put_char(pInfo, NAK); + flush(pInfo); + pInfo->state = R3964_IDLE; + break; + case R3964_WAIT_FOR_RX_REPEAT: + TRACE_PE("WAIT_FOR_RX_REPEAT - timeout"); + pInfo->state = R3964_IDLE; + break; + case R3964_WAIT_FOR_BCC: + TRACE_PE("WAIT_FOR_BCC - timeout"); + put_char(pInfo, NAK); + flush(pInfo); + pInfo->state = R3964_IDLE; + break; + } +} + +static struct r3964_client_info *findClient(struct r3964_info *pInfo, + struct pid *pid) +{ + struct r3964_client_info *pClient; + + for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) { + if (pClient->pid == pid) { + return pClient; + } + } + return NULL; +} + +static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg) +{ + struct r3964_client_info *pClient; + struct r3964_client_info **ppClient; + struct r3964_message *pMsg; + + if ((arg & R3964_SIG_ALL) == 0) { + /* Remove client from client list */ + for (ppClient = &pInfo->firstClient; *ppClient; + ppClient = &(*ppClient)->next) { + pClient = *ppClient; + + if (pClient->pid == pid) { + TRACE_PS("removing client %d from client list", + pid_nr(pid)); + *ppClient = pClient->next; + while (pClient->msg_count) { + pMsg = remove_msg(pInfo, pClient); + if (pMsg) { + kfree(pMsg); + TRACE_M("enable_signals - msg " + "kfree %p", pMsg); + } + } + put_pid(pClient->pid); + kfree(pClient); + TRACE_M("enable_signals - kfree %p", pClient); + return 0; + } + } + return -EINVAL; + } else { + pClient = findClient(pInfo, pid); + if (pClient) { + /* update signal options */ + pClient->sig_flags = arg; + } else { + /* add client to client list */ + pClient = kmalloc(sizeof(struct r3964_client_info), + GFP_KERNEL); + TRACE_M("enable_signals - kmalloc %p", pClient); + if (pClient == NULL) + return -ENOMEM; + + TRACE_PS("add client %d to client list", pid_nr(pid)); + spin_lock_init(&pClient->lock); + pClient->sig_flags = arg; + pClient->pid = get_pid(pid); + pClient->next = pInfo->firstClient; + pClient->first_msg = NULL; + pClient->last_msg = NULL; + pClient->next_block_to_read = NULL; + pClient->msg_count = 0; + pInfo->firstClient = pClient; + } + } + + return 0; +} + +static int read_telegram(struct r3964_info *pInfo, struct pid *pid, + unsigned char __user * buf) +{ + struct r3964_client_info *pClient; + struct r3964_block_header *block; + + if (!buf) { + return -EINVAL; + } + + pClient = findClient(pInfo, pid); + if (pClient == NULL) { + return -EINVAL; + } + + block = pClient->next_block_to_read; + if (!block) { + return 0; + } else { + if (copy_to_user(buf, block->data, block->length)) + return -EFAULT; + + remove_client_block(pInfo, pClient); + return block->length; + } + + return -EINVAL; +} + +static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg, + int error_code, struct r3964_block_header *pBlock) +{ + struct r3964_message *pMsg; + unsigned long flags; + + if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) { +queue_the_message: + + pMsg = kmalloc(sizeof(struct r3964_message), + error_code ? GFP_ATOMIC : GFP_KERNEL); + TRACE_M("add_msg - kmalloc %p", pMsg); + if (pMsg == NULL) { + return; + } + + spin_lock_irqsave(&pClient->lock, flags); + + pMsg->msg_id = msg_id; + pMsg->arg = arg; + pMsg->error_code = error_code; + pMsg->block = pBlock; + pMsg->next = NULL; + + if (pClient->last_msg == NULL) { + pClient->first_msg = pClient->last_msg = pMsg; + } else { + pClient->last_msg->next = pMsg; + pClient->last_msg = pMsg; + } + + pClient->msg_count++; + + if (pBlock != NULL) { + pBlock->locks++; + } + spin_unlock_irqrestore(&pClient->lock, flags); + } else { + if ((pClient->last_msg->msg_id == R3964_MSG_ACK) + && (pClient->last_msg->error_code == R3964_OVERFLOW)) { + pClient->last_msg->arg++; + TRACE_PE("add_msg - inc prev OVERFLOW-msg"); + } else { + msg_id = R3964_MSG_ACK; + arg = 0; + error_code = R3964_OVERFLOW; + pBlock = NULL; + TRACE_PE("add_msg - queue OVERFLOW-msg"); + goto queue_the_message; + } + } + /* Send SIGIO signal to client process: */ + if (pClient->sig_flags & R3964_USE_SIGIO) { + kill_pid(pClient->pid, SIGIO, 1); + } +} + +static struct r3964_message *remove_msg(struct r3964_info *pInfo, + struct r3964_client_info *pClient) +{ + struct r3964_message *pMsg = NULL; + unsigned long flags; + + if (pClient->first_msg) { + spin_lock_irqsave(&pClient->lock, flags); + + pMsg = pClient->first_msg; + pClient->first_msg = pMsg->next; + if (pClient->first_msg == NULL) { + pClient->last_msg = NULL; + } + + pClient->msg_count--; + if (pMsg->block) { + remove_client_block(pInfo, pClient); + pClient->next_block_to_read = pMsg->block; + } + spin_unlock_irqrestore(&pClient->lock, flags); + } + return pMsg; +} + +static void remove_client_block(struct r3964_info *pInfo, + struct r3964_client_info *pClient) +{ + struct r3964_block_header *block; + + TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid)); + + block = pClient->next_block_to_read; + if (block) { + block->locks--; + if (block->locks == 0) { + remove_from_rx_queue(pInfo, block); + } + } + pClient->next_block_to_read = NULL; +} + +/************************************************************* + * Line discipline routines + *************************************************************/ + +static int r3964_open(struct tty_struct *tty) +{ + struct r3964_info *pInfo; + + TRACE_L("open"); + TRACE_L("tty=%p, PID=%d, disc_data=%p", + tty, current->pid, tty->disc_data); + + pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL); + TRACE_M("r3964_open - info kmalloc %p", pInfo); + + if (!pInfo) { + printk(KERN_ERR "r3964: failed to alloc info structure\n"); + return -ENOMEM; + } + + pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL); + TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf); + + if (!pInfo->rx_buf) { + printk(KERN_ERR "r3964: failed to alloc receive buffer\n"); + kfree(pInfo); + TRACE_M("r3964_open - info kfree %p", pInfo); + return -ENOMEM; + } + + pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL); + TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf); + + if (!pInfo->tx_buf) { + printk(KERN_ERR "r3964: failed to alloc transmit buffer\n"); + kfree(pInfo->rx_buf); + TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf); + kfree(pInfo); + TRACE_M("r3964_open - info kfree %p", pInfo); + return -ENOMEM; + } + + spin_lock_init(&pInfo->lock); + pInfo->tty = tty; + init_waitqueue_head(&pInfo->read_wait); + pInfo->priority = R3964_MASTER; + pInfo->rx_first = pInfo->rx_last = NULL; + pInfo->tx_first = pInfo->tx_last = NULL; + pInfo->rx_position = 0; + pInfo->tx_position = 0; + pInfo->last_rx = 0; + pInfo->blocks_in_rx_queue = 0; + pInfo->firstClient = NULL; + pInfo->state = R3964_IDLE; + pInfo->flags = R3964_DEBUG; + pInfo->nRetry = 0; + + tty->disc_data = pInfo; + tty->receive_room = 65536; + + setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo); + + return 0; +} + +static void r3964_close(struct tty_struct *tty) +{ + struct r3964_info *pInfo = tty->disc_data; + struct r3964_client_info *pClient, *pNext; + struct r3964_message *pMsg; + struct r3964_block_header *pHeader, *pNextHeader; + unsigned long flags; + + TRACE_L("close"); + + /* + * Make sure that our task queue isn't activated. If it + * is, take it out of the linked list. + */ + del_timer_sync(&pInfo->tmr); + + /* Remove client-structs and message queues: */ + pClient = pInfo->firstClient; + while (pClient) { + pNext = pClient->next; + while (pClient->msg_count) { + pMsg = remove_msg(pInfo, pClient); + if (pMsg) { + kfree(pMsg); + TRACE_M("r3964_close - msg kfree %p", pMsg); + } + } + put_pid(pClient->pid); + kfree(pClient); + TRACE_M("r3964_close - client kfree %p", pClient); + pClient = pNext; + } + /* Remove jobs from tx_queue: */ + spin_lock_irqsave(&pInfo->lock, flags); + pHeader = pInfo->tx_first; + pInfo->tx_first = pInfo->tx_last = NULL; + spin_unlock_irqrestore(&pInfo->lock, flags); + + while (pHeader) { + pNextHeader = pHeader->next; + kfree(pHeader); + pHeader = pNextHeader; + } + + /* Free buffers: */ + wake_up_interruptible(&pInfo->read_wait); + kfree(pInfo->rx_buf); + TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf); + kfree(pInfo->tx_buf); + TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf); + kfree(pInfo); + TRACE_M("r3964_close - info kfree %p", pInfo); +} + +static ssize_t r3964_read(struct tty_struct *tty, struct file *file, + unsigned char __user * buf, size_t nr) +{ + struct r3964_info *pInfo = tty->disc_data; + struct r3964_client_info *pClient; + struct r3964_message *pMsg; + struct r3964_client_message theMsg; + int ret; + + TRACE_L("read()"); + + tty_lock(); + + pClient = findClient(pInfo, task_pid(current)); + if (pClient) { + pMsg = remove_msg(pInfo, pClient); + if (pMsg == NULL) { + /* no messages available. */ + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + goto unlock; + } + /* block until there is a message: */ + wait_event_interruptible_tty(pInfo->read_wait, + (pMsg = remove_msg(pInfo, pClient))); + } + + /* If we still haven't got a message, we must have been signalled */ + + if (!pMsg) { + ret = -EINTR; + goto unlock; + } + + /* deliver msg to client process: */ + theMsg.msg_id = pMsg->msg_id; + theMsg.arg = pMsg->arg; + theMsg.error_code = pMsg->error_code; + ret = sizeof(struct r3964_client_message); + + kfree(pMsg); + TRACE_M("r3964_read - msg kfree %p", pMsg); + + if (copy_to_user(buf, &theMsg, ret)) { + ret = -EFAULT; + goto unlock; + } + + TRACE_PS("read - return %d", ret); + goto unlock; + } + ret = -EPERM; +unlock: + tty_unlock(); + return ret; +} + +static ssize_t r3964_write(struct tty_struct *tty, struct file *file, + const unsigned char *data, size_t count) +{ + struct r3964_info *pInfo = tty->disc_data; + struct r3964_block_header *pHeader; + struct r3964_client_info *pClient; + unsigned char *new_data; + + TRACE_L("write request, %d characters", count); +/* + * Verify the pointers + */ + + if (!pInfo) + return -EIO; + +/* + * Ensure that the caller does not wish to send too much. + */ + if (count > R3964_MTU) { + if (pInfo->flags & R3964_DEBUG) { + TRACE_L(KERN_WARNING "r3964_write: truncating user " + "packet from %u to mtu %d", count, R3964_MTU); + } + count = R3964_MTU; + } +/* + * Allocate a buffer for the data and copy it from the buffer with header prepended + */ + new_data = kmalloc(count + sizeof(struct r3964_block_header), + GFP_KERNEL); + TRACE_M("r3964_write - kmalloc %p", new_data); + if (new_data == NULL) { + if (pInfo->flags & R3964_DEBUG) { + printk(KERN_ERR "r3964_write: no memory\n"); + } + return -ENOSPC; + } + + pHeader = (struct r3964_block_header *)new_data; + pHeader->data = new_data + sizeof(struct r3964_block_header); + pHeader->length = count; + pHeader->locks = 0; + pHeader->owner = NULL; + + tty_lock(); + + pClient = findClient(pInfo, task_pid(current)); + if (pClient) { + pHeader->owner = pClient; + } + + memcpy(pHeader->data, data, count); /* We already verified this */ + + if (pInfo->flags & R3964_DEBUG) { + dump_block(pHeader->data, count); + } + +/* + * Add buffer to transmit-queue: + */ + add_tx_queue(pInfo, pHeader); + trigger_transmit(pInfo); + + tty_unlock(); + + return 0; +} + +static int r3964_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct r3964_info *pInfo = tty->disc_data; + if (pInfo == NULL) + return -EINVAL; + switch (cmd) { + case R3964_ENABLE_SIGNALS: + return enable_signals(pInfo, task_pid(current), arg); + case R3964_SETPRIORITY: + if (arg < R3964_MASTER || arg > R3964_SLAVE) + return -EINVAL; + pInfo->priority = arg & 0xff; + return 0; + case R3964_USE_BCC: + if (arg) + pInfo->flags |= R3964_BCC; + else + pInfo->flags &= ~R3964_BCC; + return 0; + case R3964_READ_TELEGRAM: + return read_telegram(pInfo, task_pid(current), + (unsigned char __user *)arg); + default: + return -ENOIOCTLCMD; + } +} + +static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old) +{ + TRACE_L("set_termios"); +} + +/* Called without the kernel lock held - fine */ +static unsigned int r3964_poll(struct tty_struct *tty, struct file *file, + struct poll_table_struct *wait) +{ + struct r3964_info *pInfo = tty->disc_data; + struct r3964_client_info *pClient; + struct r3964_message *pMsg = NULL; + unsigned long flags; + int result = POLLOUT; + + TRACE_L("POLL"); + + pClient = findClient(pInfo, task_pid(current)); + if (pClient) { + poll_wait(file, &pInfo->read_wait, wait); + spin_lock_irqsave(&pInfo->lock, flags); + pMsg = pClient->first_msg; + spin_unlock_irqrestore(&pInfo->lock, flags); + if (pMsg) + result |= POLLIN | POLLRDNORM; + } else { + result = -EINVAL; + } + return result; +} + +static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + struct r3964_info *pInfo = tty->disc_data; + const unsigned char *p; + char *f, flags = 0; + int i; + + for (i = count, p = cp, f = fp; i; i--, p++) { + if (f) + flags = *f++; + if (flags == TTY_NORMAL) { + receive_char(pInfo, *p); + } else { + receive_error(pInfo, flags); + } + + } +} + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_LDISC(N_R3964); diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c new file mode 100644 index 00000000000..428f4fe0b5f --- /dev/null +++ b/drivers/tty/n_tty.c @@ -0,0 +1,2121 @@ +/* + * n_tty.c --- implements the N_TTY line discipline. + * + * This code used to be in tty_io.c, but things are getting hairy + * enough that it made sense to split things off. (The N_TTY + * processing has changed so much that it's hardly recognizable, + * anyway...) + * + * Note that the open routine for N_TTY is guaranteed never to return + * an error. This is because Linux will fall back to setting a line + * to N_TTY if it can not switch to any other line discipline. + * + * Written by Theodore Ts'o, Copyright 1994. + * + * This file also contains code originally written by Linus Torvalds, + * Copyright 1991, 1992, 1993, and by Julian Cowley, Copyright 1994. + * + * This file may be redistributed under the terms of the GNU General Public + * License. + * + * Reduced memory usage for older ARM systems - Russell King. + * + * 2000/01/20 Fixed SMP locking on put_tty_queue using bits of + * the patch by Andrew J. Kroll <ag784@freenet.buffalo.edu> + * who actually finally proved there really was a race. + * + * 2002/03/18 Implemented n_tty_wakeup to send SIGIO POLL_OUTs to + * waiting writing processes-Sapan Bhatia <sapan@corewars.org>. + * Also fixed a bug in BLOCKING mode where n_tty_write returns + * EAGAIN + */ + +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/timer.h> +#include <linux/ctype.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/bitops.h> +#include <linux/audit.h> +#include <linux/file.h> +#include <linux/uaccess.h> +#include <linux/module.h> + +#include <asm/system.h> + +/* number of characters left in xmit buffer before select has we have room */ +#define WAKEUP_CHARS 256 + +/* + * This defines the low- and high-watermarks for throttling and + * unthrottling the TTY driver. These watermarks are used for + * controlling the space in the read buffer. + */ +#define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ +#define TTY_THRESHOLD_UNTHROTTLE 128 + +/* + * Special byte codes used in the echo buffer to represent operations + * or special handling of characters. Bytes in the echo buffer that + * are not part of such special blocks are treated as normal character + * codes. + */ +#define ECHO_OP_START 0xff +#define ECHO_OP_MOVE_BACK_COL 0x80 +#define ECHO_OP_SET_CANON_COL 0x81 +#define ECHO_OP_ERASE_TAB 0x82 + +static inline int tty_put_user(struct tty_struct *tty, unsigned char x, + unsigned char __user *ptr) +{ + tty_audit_add_data(tty, &x, 1); + return put_user(x, ptr); +} + +/** + * n_tty_set__room - receive space + * @tty: terminal + * + * Called by the driver to find out how much data it is + * permitted to feed to the line discipline without any being lost + * and thus to manage flow control. Not serialized. Answers for the + * "instant". + */ + +static void n_tty_set_room(struct tty_struct *tty) +{ + /* tty->read_cnt is not read locked ? */ + int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; + + /* + * If we are doing input canonicalization, and there are no + * pending newlines, let characters through without limit, so + * that erase characters will be handled. Other excess + * characters will be beeped. + */ + if (left <= 0) + left = tty->icanon && !tty->canon_data; + tty->receive_room = left; +} + +static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) +{ + if (tty->read_cnt < N_TTY_BUF_SIZE) { + tty->read_buf[tty->read_head] = c; + tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1); + tty->read_cnt++; + } +} + +/** + * put_tty_queue - add character to tty + * @c: character + * @tty: tty device + * + * Add a character to the tty read_buf queue. This is done under the + * read_lock to serialize character addition and also to protect us + * against parallel reads or flushes + */ + +static void put_tty_queue(unsigned char c, struct tty_struct *tty) +{ + unsigned long flags; + /* + * The problem of stomping on the buffers ends here. + * Why didn't anyone see this one coming? --AJK + */ + spin_lock_irqsave(&tty->read_lock, flags); + put_tty_queue_nolock(c, tty); + spin_unlock_irqrestore(&tty->read_lock, flags); +} + +/** + * check_unthrottle - allow new receive data + * @tty; tty device + * + * Check whether to call the driver unthrottle functions + * + * Can sleep, may be called under the atomic_read_lock mutex but + * this is not guaranteed. + */ +static void check_unthrottle(struct tty_struct *tty) +{ + if (tty->count) + tty_unthrottle(tty); +} + +/** + * reset_buffer_flags - reset buffer state + * @tty: terminal to reset + * + * Reset the read buffer counters, clear the flags, + * and make sure the driver is unthrottled. Called + * from n_tty_open() and n_tty_flush_buffer(). + * + * Locking: tty_read_lock for read fields. + */ + +static void reset_buffer_flags(struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_head = tty->read_tail = tty->read_cnt = 0; + spin_unlock_irqrestore(&tty->read_lock, flags); + + mutex_lock(&tty->echo_lock); + tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; + mutex_unlock(&tty->echo_lock); + + tty->canon_head = tty->canon_data = tty->erasing = 0; + memset(&tty->read_flags, 0, sizeof tty->read_flags); + n_tty_set_room(tty); + check_unthrottle(tty); +} + +/** + * n_tty_flush_buffer - clean input queue + * @tty: terminal device + * + * Flush the input buffer. Called when the line discipline is + * being closed, when the tty layer wants the buffer flushed (eg + * at hangup) or when the N_TTY line discipline internally has to + * clean the pending queue (for example some signals). + * + * Locking: ctrl_lock, read_lock. + */ + +static void n_tty_flush_buffer(struct tty_struct *tty) +{ + unsigned long flags; + /* clear everything and unthrottle the driver */ + reset_buffer_flags(tty); + + if (!tty->link) + return; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->link->packet) { + tty->ctrl_status |= TIOCPKT_FLUSHREAD; + wake_up_interruptible(&tty->link->read_wait); + } + spin_unlock_irqrestore(&tty->ctrl_lock, flags); +} + +/** + * n_tty_chars_in_buffer - report available bytes + * @tty: tty device + * + * Report the number of characters buffered to be delivered to user + * at this instant in time. + * + * Locking: read_lock + */ + +static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) +{ + unsigned long flags; + ssize_t n = 0; + + spin_lock_irqsave(&tty->read_lock, flags); + if (!tty->icanon) { + n = tty->read_cnt; + } else if (tty->canon_data) { + n = (tty->canon_head > tty->read_tail) ? + tty->canon_head - tty->read_tail : + tty->canon_head + (N_TTY_BUF_SIZE - tty->read_tail); + } + spin_unlock_irqrestore(&tty->read_lock, flags); + return n; +} + +/** + * is_utf8_continuation - utf8 multibyte check + * @c: byte to check + * + * Returns true if the utf8 character 'c' is a multibyte continuation + * character. We use this to correctly compute the on screen size + * of the character when printing + */ + +static inline int is_utf8_continuation(unsigned char c) +{ + return (c & 0xc0) == 0x80; +} + +/** + * is_continuation - multibyte check + * @c: byte to check + * + * Returns true if the utf8 character 'c' is a multibyte continuation + * character and the terminal is in unicode mode. + */ + +static inline int is_continuation(unsigned char c, struct tty_struct *tty) +{ + return I_IUTF8(tty) && is_utf8_continuation(c); +} + +/** + * do_output_char - output one character + * @c: character (or partial unicode symbol) + * @tty: terminal device + * @space: space available in tty driver write buffer + * + * This is a helper function that handles one output character + * (including special characters like TAB, CR, LF, etc.), + * doing OPOST processing and putting the results in the + * tty driver's write buffer. + * + * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY + * and NLDLY. They simply aren't relevant in the world today. + * If you ever need them, add them here. + * + * Returns the number of bytes of buffer space used or -1 if + * no space left. + * + * Locking: should be called under the output_lock to protect + * the column state and space left in the buffer + */ + +static int do_output_char(unsigned char c, struct tty_struct *tty, int space) +{ + int spaces; + + if (!space) + return -1; + + switch (c) { + case '\n': + if (O_ONLRET(tty)) + tty->column = 0; + if (O_ONLCR(tty)) { + if (space < 2) + return -1; + tty->canon_column = tty->column = 0; + tty->ops->write(tty, "\r\n", 2); + return 2; + } + tty->canon_column = tty->column; + break; + case '\r': + if (O_ONOCR(tty) && tty->column == 0) + return 0; + if (O_OCRNL(tty)) { + c = '\n'; + if (O_ONLRET(tty)) + tty->canon_column = tty->column = 0; + break; + } + tty->canon_column = tty->column = 0; + break; + case '\t': + spaces = 8 - (tty->column & 7); + if (O_TABDLY(tty) == XTABS) { + if (space < spaces) + return -1; + tty->column += spaces; + tty->ops->write(tty, " ", spaces); + return spaces; + } + tty->column += spaces; + break; + case '\b': + if (tty->column > 0) + tty->column--; + break; + default: + if (!iscntrl(c)) { + if (O_OLCUC(tty)) + c = toupper(c); + if (!is_continuation(c, tty)) + tty->column++; + } + break; + } + + tty_put_char(tty, c); + return 1; +} + +/** + * process_output - output post processor + * @c: character (or partial unicode symbol) + * @tty: terminal device + * + * Output one character with OPOST processing. + * Returns -1 when the output device is full and the character + * must be retried. + * + * Locking: output_lock to protect column state and space left + * (also, this is called from n_tty_write under the + * tty layer write lock) + */ + +static int process_output(unsigned char c, struct tty_struct *tty) +{ + int space, retval; + + mutex_lock(&tty->output_lock); + + space = tty_write_room(tty); + retval = do_output_char(c, tty, space); + + mutex_unlock(&tty->output_lock); + if (retval < 0) + return -1; + else + return 0; +} + +/** + * process_output_block - block post processor + * @tty: terminal device + * @buf: character buffer + * @nr: number of bytes to output + * + * Output a block of characters with OPOST processing. + * Returns the number of characters output. + * + * This path is used to speed up block console writes, among other + * things when processing blocks of output data. It handles only + * the simple cases normally found and helps to generate blocks of + * symbols for the console driver and thus improve performance. + * + * Locking: output_lock to protect column state and space left + * (also, this is called from n_tty_write under the + * tty layer write lock) + */ + +static ssize_t process_output_block(struct tty_struct *tty, + const unsigned char *buf, unsigned int nr) +{ + int space; + int i; + const unsigned char *cp; + + mutex_lock(&tty->output_lock); + + space = tty_write_room(tty); + if (!space) { + mutex_unlock(&tty->output_lock); + return 0; + } + if (nr > space) + nr = space; + + for (i = 0, cp = buf; i < nr; i++, cp++) { + unsigned char c = *cp; + + switch (c) { + case '\n': + if (O_ONLRET(tty)) + tty->column = 0; + if (O_ONLCR(tty)) + goto break_out; + tty->canon_column = tty->column; + break; + case '\r': + if (O_ONOCR(tty) && tty->column == 0) + goto break_out; + if (O_OCRNL(tty)) + goto break_out; + tty->canon_column = tty->column = 0; + break; + case '\t': + goto break_out; + case '\b': + if (tty->column > 0) + tty->column--; + break; + default: + if (!iscntrl(c)) { + if (O_OLCUC(tty)) + goto break_out; + if (!is_continuation(c, tty)) + tty->column++; + } + break; + } + } +break_out: + i = tty->ops->write(tty, buf, i); + + mutex_unlock(&tty->output_lock); + return i; +} + +/** + * process_echoes - write pending echo characters + * @tty: terminal device + * + * Write previously buffered echo (and other ldisc-generated) + * characters to the tty. + * + * Characters generated by the ldisc (including echoes) need to + * be buffered because the driver's write buffer can fill during + * heavy program output. Echoing straight to the driver will + * often fail under these conditions, causing lost characters and + * resulting mismatches of ldisc state information. + * + * Since the ldisc state must represent the characters actually sent + * to the driver at the time of the write, operations like certain + * changes in column state are also saved in the buffer and executed + * here. + * + * A circular fifo buffer is used so that the most recent characters + * are prioritized. Also, when control characters are echoed with a + * prefixed "^", the pair is treated atomically and thus not separated. + * + * Locking: output_lock to protect column state and space left, + * echo_lock to protect the echo buffer + */ + +static void process_echoes(struct tty_struct *tty) +{ + int space, nr; + unsigned char c; + unsigned char *cp, *buf_end; + + if (!tty->echo_cnt) + return; + + mutex_lock(&tty->output_lock); + mutex_lock(&tty->echo_lock); + + space = tty_write_room(tty); + + buf_end = tty->echo_buf + N_TTY_BUF_SIZE; + cp = tty->echo_buf + tty->echo_pos; + nr = tty->echo_cnt; + while (nr > 0) { + c = *cp; + if (c == ECHO_OP_START) { + unsigned char op; + unsigned char *opp; + int no_space_left = 0; + + /* + * If the buffer byte is the start of a multi-byte + * operation, get the next byte, which is either the + * op code or a control character value. + */ + opp = cp + 1; + if (opp == buf_end) + opp -= N_TTY_BUF_SIZE; + op = *opp; + + switch (op) { + unsigned int num_chars, num_bs; + + case ECHO_OP_ERASE_TAB: + if (++opp == buf_end) + opp -= N_TTY_BUF_SIZE; + num_chars = *opp; + + /* + * Determine how many columns to go back + * in order to erase the tab. + * This depends on the number of columns + * used by other characters within the tab + * area. If this (modulo 8) count is from + * the start of input rather than from a + * previous tab, we offset by canon column. + * Otherwise, tab spacing is normal. + */ + if (!(num_chars & 0x80)) + num_chars += tty->canon_column; + num_bs = 8 - (num_chars & 7); + + if (num_bs > space) { + no_space_left = 1; + break; + } + space -= num_bs; + while (num_bs--) { + tty_put_char(tty, '\b'); + if (tty->column > 0) + tty->column--; + } + cp += 3; + nr -= 3; + break; + + case ECHO_OP_SET_CANON_COL: + tty->canon_column = tty->column; + cp += 2; + nr -= 2; + break; + + case ECHO_OP_MOVE_BACK_COL: + if (tty->column > 0) + tty->column--; + cp += 2; + nr -= 2; + break; + + case ECHO_OP_START: + /* This is an escaped echo op start code */ + if (!space) { + no_space_left = 1; + break; + } + tty_put_char(tty, ECHO_OP_START); + tty->column++; + space--; + cp += 2; + nr -= 2; + break; + + default: + /* + * If the op is not a special byte code, + * it is a ctrl char tagged to be echoed + * as "^X" (where X is the letter + * representing the control char). + * Note that we must ensure there is + * enough space for the whole ctrl pair. + * + */ + if (space < 2) { + no_space_left = 1; + break; + } + tty_put_char(tty, '^'); + tty_put_char(tty, op ^ 0100); + tty->column += 2; + space -= 2; + cp += 2; + nr -= 2; + } + + if (no_space_left) + break; + } else { + if (O_OPOST(tty) && + !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { + int retval = do_output_char(c, tty, space); + if (retval < 0) + break; + space -= retval; + } else { + if (!space) + break; + tty_put_char(tty, c); + space -= 1; + } + cp += 1; + nr -= 1; + } + + /* When end of circular buffer reached, wrap around */ + if (cp >= buf_end) + cp -= N_TTY_BUF_SIZE; + } + + if (nr == 0) { + tty->echo_pos = 0; + tty->echo_cnt = 0; + tty->echo_overrun = 0; + } else { + int num_processed = tty->echo_cnt - nr; + tty->echo_pos += num_processed; + tty->echo_pos &= N_TTY_BUF_SIZE - 1; + tty->echo_cnt = nr; + if (num_processed > 0) + tty->echo_overrun = 0; + } + + mutex_unlock(&tty->echo_lock); + mutex_unlock(&tty->output_lock); + + if (tty->ops->flush_chars) + tty->ops->flush_chars(tty); +} + +/** + * add_echo_byte - add a byte to the echo buffer + * @c: unicode byte to echo + * @tty: terminal device + * + * Add a character or operation byte to the echo buffer. + * + * Should be called under the echo lock to protect the echo buffer. + */ + +static void add_echo_byte(unsigned char c, struct tty_struct *tty) +{ + int new_byte_pos; + + if (tty->echo_cnt == N_TTY_BUF_SIZE) { + /* Circular buffer is already at capacity */ + new_byte_pos = tty->echo_pos; + + /* + * Since the buffer start position needs to be advanced, + * be sure to step by a whole operation byte group. + */ + if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { + if (tty->echo_buf[(tty->echo_pos + 1) & + (N_TTY_BUF_SIZE - 1)] == + ECHO_OP_ERASE_TAB) { + tty->echo_pos += 3; + tty->echo_cnt -= 2; + } else { + tty->echo_pos += 2; + tty->echo_cnt -= 1; + } + } else { + tty->echo_pos++; + } + tty->echo_pos &= N_TTY_BUF_SIZE - 1; + + tty->echo_overrun = 1; + } else { + new_byte_pos = tty->echo_pos + tty->echo_cnt; + new_byte_pos &= N_TTY_BUF_SIZE - 1; + tty->echo_cnt++; + } + + tty->echo_buf[new_byte_pos] = c; +} + +/** + * echo_move_back_col - add operation to move back a column + * @tty: terminal device + * + * Add an operation to the echo buffer to move back one column. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_move_back_col(struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_set_canon_col - add operation to set the canon column + * @tty: terminal device + * + * Add an operation to the echo buffer to set the canon column + * to the current column. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_set_canon_col(struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_SET_CANON_COL, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_erase_tab - add operation to erase a tab + * @num_chars: number of character columns already used + * @after_tab: true if num_chars starts after a previous tab + * @tty: terminal device + * + * Add an operation to the echo buffer to erase a tab. + * + * Called by the eraser function, which knows how many character + * columns have been used since either a previous tab or the start + * of input. This information will be used later, along with + * canon column (if applicable), to go back the correct number + * of columns. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_erase_tab(unsigned int num_chars, int after_tab, + struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_ERASE_TAB, tty); + + /* We only need to know this modulo 8 (tab spacing) */ + num_chars &= 7; + + /* Set the high bit as a flag if num_chars is after a previous tab */ + if (after_tab) + num_chars |= 0x80; + + add_echo_byte(num_chars, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_char_raw - echo a character raw + * @c: unicode byte to echo + * @tty: terminal device + * + * Echo user input back onto the screen. This must be called only when + * L_ECHO(tty) is true. Called from the driver receive_buf path. + * + * This variant does not treat control characters specially. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_char_raw(unsigned char c, struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + if (c == ECHO_OP_START) { + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, tty); + } else { + add_echo_byte(c, tty); + } + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_char - echo a character + * @c: unicode byte to echo + * @tty: terminal device + * + * Echo user input back onto the screen. This must be called only when + * L_ECHO(tty) is true. Called from the driver receive_buf path. + * + * This variant tags control characters to be echoed as "^X" + * (where X is the letter representing the control char). + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_char(unsigned char c, struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + if (c == ECHO_OP_START) { + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, tty); + } else { + if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(c, tty); + } + + mutex_unlock(&tty->echo_lock); +} + +/** + * finish_erasing - complete erase + * @tty: tty doing the erase + */ + +static inline void finish_erasing(struct tty_struct *tty) +{ + if (tty->erasing) { + echo_char_raw('/', tty); + tty->erasing = 0; + } +} + +/** + * eraser - handle erase function + * @c: character input + * @tty: terminal device + * + * Perform erase and necessary output when an erase character is + * present in the stream from the driver layer. Handles the complexities + * of UTF-8 multibyte symbols. + * + * Locking: read_lock for tty buffers + */ + +static void eraser(unsigned char c, struct tty_struct *tty) +{ + enum { ERASE, WERASE, KILL } kill_type; + int head, seen_alnums, cnt; + unsigned long flags; + + /* FIXME: locking needed ? */ + if (tty->read_head == tty->canon_head) { + /* process_output('\a', tty); */ /* what do you think? */ + return; + } + if (c == ERASE_CHAR(tty)) + kill_type = ERASE; + else if (c == WERASE_CHAR(tty)) + kill_type = WERASE; + else { + if (!L_ECHO(tty)) { + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_cnt -= ((tty->read_head - tty->canon_head) & + (N_TTY_BUF_SIZE - 1)); + tty->read_head = tty->canon_head; + spin_unlock_irqrestore(&tty->read_lock, flags); + return; + } + if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_cnt -= ((tty->read_head - tty->canon_head) & + (N_TTY_BUF_SIZE - 1)); + tty->read_head = tty->canon_head; + spin_unlock_irqrestore(&tty->read_lock, flags); + finish_erasing(tty); + echo_char(KILL_CHAR(tty), tty); + /* Add a newline if ECHOK is on and ECHOKE is off. */ + if (L_ECHOK(tty)) + echo_char_raw('\n', tty); + return; + } + kill_type = KILL; + } + + seen_alnums = 0; + /* FIXME: Locking ?? */ + while (tty->read_head != tty->canon_head) { + head = tty->read_head; + + /* erase a single possibly multibyte character */ + do { + head = (head - 1) & (N_TTY_BUF_SIZE-1); + c = tty->read_buf[head]; + } while (is_continuation(c, tty) && head != tty->canon_head); + + /* do not partially erase */ + if (is_continuation(c, tty)) + break; + + if (kill_type == WERASE) { + /* Equivalent to BSD's ALTWERASE. */ + if (isalnum(c) || c == '_') + seen_alnums++; + else if (seen_alnums) + break; + } + cnt = (tty->read_head - head) & (N_TTY_BUF_SIZE-1); + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_head = head; + tty->read_cnt -= cnt; + spin_unlock_irqrestore(&tty->read_lock, flags); + if (L_ECHO(tty)) { + if (L_ECHOPRT(tty)) { + if (!tty->erasing) { + echo_char_raw('\\', tty); + tty->erasing = 1; + } + /* if cnt > 1, output a multi-byte character */ + echo_char(c, tty); + while (--cnt > 0) { + head = (head+1) & (N_TTY_BUF_SIZE-1); + echo_char_raw(tty->read_buf[head], tty); + echo_move_back_col(tty); + } + } else if (kill_type == ERASE && !L_ECHOE(tty)) { + echo_char(ERASE_CHAR(tty), tty); + } else if (c == '\t') { + unsigned int num_chars = 0; + int after_tab = 0; + unsigned long tail = tty->read_head; + + /* + * Count the columns used for characters + * since the start of input or after a + * previous tab. + * This info is used to go back the correct + * number of columns. + */ + while (tail != tty->canon_head) { + tail = (tail-1) & (N_TTY_BUF_SIZE-1); + c = tty->read_buf[tail]; + if (c == '\t') { + after_tab = 1; + break; + } else if (iscntrl(c)) { + if (L_ECHOCTL(tty)) + num_chars += 2; + } else if (!is_continuation(c, tty)) { + num_chars++; + } + } + echo_erase_tab(num_chars, after_tab, tty); + } else { + if (iscntrl(c) && L_ECHOCTL(tty)) { + echo_char_raw('\b', tty); + echo_char_raw(' ', tty); + echo_char_raw('\b', tty); + } + if (!iscntrl(c) || L_ECHOCTL(tty)) { + echo_char_raw('\b', tty); + echo_char_raw(' ', tty); + echo_char_raw('\b', tty); + } + } + } + if (kill_type == ERASE) + break; + } + if (tty->read_head == tty->canon_head && L_ECHO(tty)) + finish_erasing(tty); +} + +/** + * isig - handle the ISIG optio + * @sig: signal + * @tty: terminal + * @flush: force flush + * + * Called when a signal is being sent due to terminal input. This + * may caus terminal flushing to take place according to the termios + * settings and character used. Called from the driver receive_buf + * path so serialized. + * + * Locking: ctrl_lock, read_lock (both via flush buffer) + */ + +static inline void isig(int sig, struct tty_struct *tty, int flush) +{ + if (tty->pgrp) + kill_pgrp(tty->pgrp, sig, 1); + if (flush || !L_NOFLSH(tty)) { + n_tty_flush_buffer(tty); + tty_driver_flush_buffer(tty); + } +} + +/** + * n_tty_receive_break - handle break + * @tty: terminal + * + * An RS232 break event has been hit in the incoming bitstream. This + * can cause a variety of events depending upon the termios settings. + * + * Called from the receive_buf path so single threaded. + */ + +static inline void n_tty_receive_break(struct tty_struct *tty) +{ + if (I_IGNBRK(tty)) + return; + if (I_BRKINT(tty)) { + isig(SIGINT, tty, 1); + return; + } + if (I_PARMRK(tty)) { + put_tty_queue('\377', tty); + put_tty_queue('\0', tty); + } + put_tty_queue('\0', tty); + wake_up_interruptible(&tty->read_wait); +} + +/** + * n_tty_receive_overrun - handle overrun reporting + * @tty: terminal + * + * Data arrived faster than we could process it. While the tty + * driver has flagged this the bits that were missed are gone + * forever. + * + * Called from the receive_buf path so single threaded. Does not + * need locking as num_overrun and overrun_time are function + * private. + */ + +static inline void n_tty_receive_overrun(struct tty_struct *tty) +{ + char buf[64]; + + tty->num_overrun++; + if (time_before(tty->overrun_time, jiffies - HZ) || + time_after(tty->overrun_time, jiffies)) { + printk(KERN_WARNING "%s: %d input overrun(s)\n", + tty_name(tty, buf), + tty->num_overrun); + tty->overrun_time = jiffies; + tty->num_overrun = 0; + } +} + +/** + * n_tty_receive_parity_error - error notifier + * @tty: terminal device + * @c: character + * + * Process a parity error and queue the right data to indicate + * the error case if necessary. Locking as per n_tty_receive_buf. + */ +static inline void n_tty_receive_parity_error(struct tty_struct *tty, + unsigned char c) +{ + if (I_IGNPAR(tty)) + return; + if (I_PARMRK(tty)) { + put_tty_queue('\377', tty); + put_tty_queue('\0', tty); + put_tty_queue(c, tty); + } else if (I_INPCK(tty)) + put_tty_queue('\0', tty); + else + put_tty_queue(c, tty); + wake_up_interruptible(&tty->read_wait); +} + +/** + * n_tty_receive_char - perform processing + * @tty: terminal device + * @c: character + * + * Process an individual character of input received from the driver. + * This is serialized with respect to itself by the rules for the + * driver above. + */ + +static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) +{ + unsigned long flags; + int parmrk; + + if (tty->raw) { + put_tty_queue(c, tty); + return; + } + + if (I_ISTRIP(tty)) + c &= 0x7f; + if (I_IUCLC(tty) && L_IEXTEN(tty)) + c = tolower(c); + + if (L_EXTPROC(tty)) { + put_tty_queue(c, tty); + return; + } + + if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && + I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && + c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { + start_tty(tty); + process_echoes(tty); + } + + if (tty->closing) { + if (I_IXON(tty)) { + if (c == START_CHAR(tty)) { + start_tty(tty); + process_echoes(tty); + } else if (c == STOP_CHAR(tty)) + stop_tty(tty); + } + return; + } + + /* + * If the previous character was LNEXT, or we know that this + * character is not one of the characters that we'll have to + * handle specially, do shortcut processing to speed things + * up. + */ + if (!test_bit(c, tty->process_char_map) || tty->lnext) { + tty->lnext = 0; + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { + /* beep if no space */ + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } + if (L_ECHO(tty)) { + finish_erasing(tty); + /* Record the column of first canon char. */ + if (tty->canon_head == tty->read_head) + echo_set_canon_col(tty); + echo_char(c, tty); + process_echoes(tty); + } + if (parmrk) + put_tty_queue(c, tty); + put_tty_queue(c, tty); + return; + } + + if (I_IXON(tty)) { + if (c == START_CHAR(tty)) { + start_tty(tty); + process_echoes(tty); + return; + } + if (c == STOP_CHAR(tty)) { + stop_tty(tty); + return; + } + } + + if (L_ISIG(tty)) { + int signal; + signal = SIGINT; + if (c == INTR_CHAR(tty)) + goto send_signal; + signal = SIGQUIT; + if (c == QUIT_CHAR(tty)) + goto send_signal; + signal = SIGTSTP; + if (c == SUSP_CHAR(tty)) { +send_signal: + /* + * Note that we do not use isig() here because we want + * the order to be: + * 1) flush, 2) echo, 3) signal + */ + if (!L_NOFLSH(tty)) { + n_tty_flush_buffer(tty); + tty_driver_flush_buffer(tty); + } + if (I_IXON(tty)) + start_tty(tty); + if (L_ECHO(tty)) { + echo_char(c, tty); + process_echoes(tty); + } + if (tty->pgrp) + kill_pgrp(tty->pgrp, signal, 1); + return; + } + } + + if (c == '\r') { + if (I_IGNCR(tty)) + return; + if (I_ICRNL(tty)) + c = '\n'; + } else if (c == '\n' && I_INLCR(tty)) + c = '\r'; + + if (tty->icanon) { + if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || + (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { + eraser(c, tty); + process_echoes(tty); + return; + } + if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { + tty->lnext = 1; + if (L_ECHO(tty)) { + finish_erasing(tty); + if (L_ECHOCTL(tty)) { + echo_char_raw('^', tty); + echo_char_raw('\b', tty); + process_echoes(tty); + } + } + return; + } + if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && + L_IEXTEN(tty)) { + unsigned long tail = tty->canon_head; + + finish_erasing(tty); + echo_char(c, tty); + echo_char_raw('\n', tty); + while (tail != tty->read_head) { + echo_char(tty->read_buf[tail], tty); + tail = (tail+1) & (N_TTY_BUF_SIZE-1); + } + process_echoes(tty); + return; + } + if (c == '\n') { + if (tty->read_cnt >= N_TTY_BUF_SIZE) { + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } + if (L_ECHO(tty) || L_ECHONL(tty)) { + echo_char_raw('\n', tty); + process_echoes(tty); + } + goto handle_newline; + } + if (c == EOF_CHAR(tty)) { + if (tty->read_cnt >= N_TTY_BUF_SIZE) + return; + if (tty->canon_head != tty->read_head) + set_bit(TTY_PUSH, &tty->flags); + c = __DISABLED_CHAR; + goto handle_newline; + } + if ((c == EOL_CHAR(tty)) || + (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) + ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } + /* + * XXX are EOL_CHAR and EOL2_CHAR echoed?!? + */ + if (L_ECHO(tty)) { + /* Record the column of first canon char. */ + if (tty->canon_head == tty->read_head) + echo_set_canon_col(tty); + echo_char(c, tty); + process_echoes(tty); + } + /* + * XXX does PARMRK doubling happen for + * EOL_CHAR and EOL2_CHAR? + */ + if (parmrk) + put_tty_queue(c, tty); + +handle_newline: + spin_lock_irqsave(&tty->read_lock, flags); + set_bit(tty->read_head, tty->read_flags); + put_tty_queue_nolock(c, tty); + tty->canon_head = tty->read_head; + tty->canon_data++; + spin_unlock_irqrestore(&tty->read_lock, flags); + kill_fasync(&tty->fasync, SIGIO, POLL_IN); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); + return; + } + } + + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { + /* beep if no space */ + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } + if (L_ECHO(tty)) { + finish_erasing(tty); + if (c == '\n') + echo_char_raw('\n', tty); + else { + /* Record the column of first canon char. */ + if (tty->canon_head == tty->read_head) + echo_set_canon_col(tty); + echo_char(c, tty); + } + process_echoes(tty); + } + + if (parmrk) + put_tty_queue(c, tty); + + put_tty_queue(c, tty); +} + + +/** + * n_tty_write_wakeup - asynchronous I/O notifier + * @tty: tty device + * + * Required for the ptys, serial driver etc. since processes + * that attach themselves to the master and rely on ASYNC + * IO must be woken up + */ + +static void n_tty_write_wakeup(struct tty_struct *tty) +{ + if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) + kill_fasync(&tty->fasync, SIGIO, POLL_OUT); +} + +/** + * n_tty_receive_buf - data receive + * @tty: terminal device + * @cp: buffer + * @fp: flag buffer + * @count: characters + * + * Called by the terminal driver when a block of characters has + * been received. This function must be called from soft contexts + * not from interrupt context. The driver is responsible for making + * calls one at a time and in order (or using flush_to_ldisc) + */ + +static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + const unsigned char *p; + char *f, flags = TTY_NORMAL; + int i; + char buf[64]; + unsigned long cpuflags; + + if (!tty->read_buf) + return; + + if (tty->real_raw) { + spin_lock_irqsave(&tty->read_lock, cpuflags); + i = min(N_TTY_BUF_SIZE - tty->read_cnt, + N_TTY_BUF_SIZE - tty->read_head); + i = min(count, i); + memcpy(tty->read_buf + tty->read_head, cp, i); + tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); + tty->read_cnt += i; + cp += i; + count -= i; + + i = min(N_TTY_BUF_SIZE - tty->read_cnt, + N_TTY_BUF_SIZE - tty->read_head); + i = min(count, i); + memcpy(tty->read_buf + tty->read_head, cp, i); + tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); + tty->read_cnt += i; + spin_unlock_irqrestore(&tty->read_lock, cpuflags); + } else { + for (i = count, p = cp, f = fp; i; i--, p++) { + if (f) + flags = *f++; + switch (flags) { + case TTY_NORMAL: + n_tty_receive_char(tty, *p); + break; + case TTY_BREAK: + n_tty_receive_break(tty); + break; + case TTY_PARITY: + case TTY_FRAME: + n_tty_receive_parity_error(tty, *p); + break; + case TTY_OVERRUN: + n_tty_receive_overrun(tty); + break; + default: + printk(KERN_ERR "%s: unknown flag %d\n", + tty_name(tty, buf), flags); + break; + } + } + if (tty->ops->flush_chars) + tty->ops->flush_chars(tty); + } + + n_tty_set_room(tty); + + if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || + L_EXTPROC(tty)) { + kill_fasync(&tty->fasync, SIGIO, POLL_IN); + if (waitqueue_active(&tty->read_wait)) + wake_up_interruptible(&tty->read_wait); + } + + /* + * Check the remaining room for the input canonicalization + * mode. We don't want to throttle the driver if we're in + * canonical mode and don't have a newline yet! + */ + if (tty->receive_room < TTY_THRESHOLD_THROTTLE) + tty_throttle(tty); +} + +int is_ignored(int sig) +{ + return (sigismember(¤t->blocked, sig) || + current->sighand->action[sig-1].sa.sa_handler == SIG_IGN); +} + +/** + * n_tty_set_termios - termios data changed + * @tty: terminal + * @old: previous data + * + * Called by the tty layer when the user changes termios flags so + * that the line discipline can plan ahead. This function cannot sleep + * and is protected from re-entry by the tty layer. The user is + * guaranteed that this function will not be re-entered or in progress + * when the ldisc is closed. + * + * Locking: Caller holds tty->termios_mutex + */ + +static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) +{ + int canon_change = 1; + BUG_ON(!tty); + + if (old) + canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON; + if (canon_change) { + memset(&tty->read_flags, 0, sizeof tty->read_flags); + tty->canon_head = tty->read_tail; + tty->canon_data = 0; + tty->erasing = 0; + } + + if (canon_change && !L_ICANON(tty) && tty->read_cnt) + wake_up_interruptible(&tty->read_wait); + + tty->icanon = (L_ICANON(tty) != 0); + if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { + tty->raw = 1; + tty->real_raw = 1; + n_tty_set_room(tty); + return; + } + if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || + I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) || + I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) || + I_PARMRK(tty)) { + memset(tty->process_char_map, 0, 256/8); + + if (I_IGNCR(tty) || I_ICRNL(tty)) + set_bit('\r', tty->process_char_map); + if (I_INLCR(tty)) + set_bit('\n', tty->process_char_map); + + if (L_ICANON(tty)) { + set_bit(ERASE_CHAR(tty), tty->process_char_map); + set_bit(KILL_CHAR(tty), tty->process_char_map); + set_bit(EOF_CHAR(tty), tty->process_char_map); + set_bit('\n', tty->process_char_map); + set_bit(EOL_CHAR(tty), tty->process_char_map); + if (L_IEXTEN(tty)) { + set_bit(WERASE_CHAR(tty), + tty->process_char_map); + set_bit(LNEXT_CHAR(tty), + tty->process_char_map); + set_bit(EOL2_CHAR(tty), + tty->process_char_map); + if (L_ECHO(tty)) + set_bit(REPRINT_CHAR(tty), + tty->process_char_map); + } + } + if (I_IXON(tty)) { + set_bit(START_CHAR(tty), tty->process_char_map); + set_bit(STOP_CHAR(tty), tty->process_char_map); + } + if (L_ISIG(tty)) { + set_bit(INTR_CHAR(tty), tty->process_char_map); + set_bit(QUIT_CHAR(tty), tty->process_char_map); + set_bit(SUSP_CHAR(tty), tty->process_char_map); + } + clear_bit(__DISABLED_CHAR, tty->process_char_map); + tty->raw = 0; + tty->real_raw = 0; + } else { + tty->raw = 1; + if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) && + (I_IGNPAR(tty) || !I_INPCK(tty)) && + (tty->driver->flags & TTY_DRIVER_REAL_RAW)) + tty->real_raw = 1; + else + tty->real_raw = 0; + } + n_tty_set_room(tty); + /* The termios change make the tty ready for I/O */ + wake_up_interruptible(&tty->write_wait); + wake_up_interruptible(&tty->read_wait); +} + +/** + * n_tty_close - close the ldisc for this tty + * @tty: device + * + * Called from the terminal layer when this line discipline is + * being shut down, either because of a close or becsuse of a + * discipline change. The function will not be called while other + * ldisc methods are in progress. + */ + +static void n_tty_close(struct tty_struct *tty) +{ + n_tty_flush_buffer(tty); + if (tty->read_buf) { + kfree(tty->read_buf); + tty->read_buf = NULL; + } + if (tty->echo_buf) { + kfree(tty->echo_buf); + tty->echo_buf = NULL; + } +} + +/** + * n_tty_open - open an ldisc + * @tty: terminal to open + * + * Called when this line discipline is being attached to the + * terminal device. Can sleep. Called serialized so that no + * other events will occur in parallel. No further open will occur + * until a close. + */ + +static int n_tty_open(struct tty_struct *tty) +{ + if (!tty) + return -EINVAL; + + /* These are ugly. Currently a malloc failure here can panic */ + if (!tty->read_buf) { + tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); + if (!tty->read_buf) + return -ENOMEM; + } + if (!tty->echo_buf) { + tty->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); + + if (!tty->echo_buf) + return -ENOMEM; + } + reset_buffer_flags(tty); + tty->column = 0; + n_tty_set_termios(tty, NULL); + tty->minimum_to_wake = 1; + tty->closing = 0; + return 0; +} + +static inline int input_available_p(struct tty_struct *tty, int amt) +{ + tty_flush_to_ldisc(tty); + if (tty->icanon && !L_EXTPROC(tty)) { + if (tty->canon_data) + return 1; + } else if (tty->read_cnt >= (amt ? amt : 1)) + return 1; + + return 0; +} + +/** + * copy_from_read_buf - copy read data directly + * @tty: terminal device + * @b: user data + * @nr: size of data + * + * Helper function to speed up n_tty_read. It is only called when + * ICANON is off; it copies characters straight from the tty queue to + * user space directly. It can be profitably called twice; once to + * drain the space from the tail pointer to the (physical) end of the + * buffer, and once to drain the space from the (physical) beginning of + * the buffer to head pointer. + * + * Called under the tty->atomic_read_lock sem + * + */ + +static int copy_from_read_buf(struct tty_struct *tty, + unsigned char __user **b, + size_t *nr) + +{ + int retval; + size_t n; + unsigned long flags; + + retval = 0; + spin_lock_irqsave(&tty->read_lock, flags); + n = min(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail); + n = min(*nr, n); + spin_unlock_irqrestore(&tty->read_lock, flags); + if (n) { + retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n); + n -= retval; + tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n); + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1); + tty->read_cnt -= n; + /* Turn single EOF into zero-length read */ + if (L_EXTPROC(tty) && tty->icanon && n == 1) { + if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty)) + n--; + } + spin_unlock_irqrestore(&tty->read_lock, flags); + *b += n; + *nr -= n; + } + return retval; +} + +extern ssize_t redirected_tty_write(struct file *, const char __user *, + size_t, loff_t *); + +/** + * job_control - check job control + * @tty: tty + * @file: file handle + * + * Perform job control management checks on this file/tty descriptor + * and if appropriate send any needed signals and return a negative + * error code if action should be taken. + * + * FIXME: + * Locking: None - redirected write test is safe, testing + * current->signal should possibly lock current->sighand + * pgrp locking ? + */ + +static int job_control(struct tty_struct *tty, struct file *file) +{ + /* Job control check -- must be done at start and after + every sleep (POSIX.1 7.1.1.4). */ + /* NOTE: not yet done after every sleep pending a thorough + check of the logic of this change. -- jlc */ + /* don't stop on /dev/console */ + if (file->f_op->write != redirected_tty_write && + current->signal->tty == tty) { + if (!tty->pgrp) + printk(KERN_ERR "n_tty_read: no tty->pgrp!\n"); + else if (task_pgrp(current) != tty->pgrp) { + if (is_ignored(SIGTTIN) || + is_current_pgrp_orphaned()) + return -EIO; + kill_pgrp(task_pgrp(current), SIGTTIN, 1); + set_thread_flag(TIF_SIGPENDING); + return -ERESTARTSYS; + } + } + return 0; +} + + +/** + * n_tty_read - read function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Perform reads for the line discipline. We are guaranteed that the + * line discipline will not be closed under us but we may get multiple + * parallel readers and must handle this ourselves. We may also get + * a hangup. Always called in user context, may sleep. + * + * This code must be sure never to sleep through a hangup. + */ + +static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, + unsigned char __user *buf, size_t nr) +{ + unsigned char __user *b = buf; + DECLARE_WAITQUEUE(wait, current); + int c; + int minimum, time; + ssize_t retval = 0; + ssize_t size; + long timeout; + unsigned long flags; + int packet; + +do_it_again: + + BUG_ON(!tty->read_buf); + + c = job_control(tty, file); + if (c < 0) + return c; + + minimum = time = 0; + timeout = MAX_SCHEDULE_TIMEOUT; + if (!tty->icanon) { + time = (HZ / 10) * TIME_CHAR(tty); + minimum = MIN_CHAR(tty); + if (minimum) { + if (time) + tty->minimum_to_wake = 1; + else if (!waitqueue_active(&tty->read_wait) || + (tty->minimum_to_wake > minimum)) + tty->minimum_to_wake = minimum; + } else { + timeout = 0; + if (time) { + timeout = time; + time = 0; + } + tty->minimum_to_wake = minimum = 1; + } + } + + /* + * Internal serialization of reads. + */ + if (file->f_flags & O_NONBLOCK) { + if (!mutex_trylock(&tty->atomic_read_lock)) + return -EAGAIN; + } else { + if (mutex_lock_interruptible(&tty->atomic_read_lock)) + return -ERESTARTSYS; + } + packet = tty->packet; + + add_wait_queue(&tty->read_wait, &wait); + while (nr) { + /* First test for status change. */ + if (packet && tty->link->ctrl_status) { + unsigned char cs; + if (b != buf) + break; + spin_lock_irqsave(&tty->link->ctrl_lock, flags); + cs = tty->link->ctrl_status; + tty->link->ctrl_status = 0; + spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); + if (tty_put_user(tty, cs, b++)) { + retval = -EFAULT; + b--; + break; + } + nr--; + break; + } + /* This statement must be first before checking for input + so that any interrupt will set the state back to + TASK_RUNNING. */ + set_current_state(TASK_INTERRUPTIBLE); + + if (((minimum - (b - buf)) < tty->minimum_to_wake) && + ((minimum - (b - buf)) >= 1)) + tty->minimum_to_wake = (minimum - (b - buf)); + + if (!input_available_p(tty, 0)) { + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + retval = -EIO; + break; + } + if (tty_hung_up_p(file)) + break; + if (!timeout) + break; + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + /* FIXME: does n_tty_set_room need locking ? */ + n_tty_set_room(tty); + timeout = schedule_timeout(timeout); + continue; + } + __set_current_state(TASK_RUNNING); + + /* Deal with packet mode. */ + if (packet && b == buf) { + if (tty_put_user(tty, TIOCPKT_DATA, b++)) { + retval = -EFAULT; + b--; + break; + } + nr--; + } + + if (tty->icanon && !L_EXTPROC(tty)) { + /* N.B. avoid overrun if nr == 0 */ + while (nr && tty->read_cnt) { + int eol; + + eol = test_and_clear_bit(tty->read_tail, + tty->read_flags); + c = tty->read_buf[tty->read_tail]; + spin_lock_irqsave(&tty->read_lock, flags); + tty->read_tail = ((tty->read_tail+1) & + (N_TTY_BUF_SIZE-1)); + tty->read_cnt--; + if (eol) { + /* this test should be redundant: + * we shouldn't be reading data if + * canon_data is 0 + */ + if (--tty->canon_data < 0) + tty->canon_data = 0; + } + spin_unlock_irqrestore(&tty->read_lock, flags); + + if (!eol || (c != __DISABLED_CHAR)) { + if (tty_put_user(tty, c, b++)) { + retval = -EFAULT; + b--; + break; + } + nr--; + } + if (eol) { + tty_audit_push(tty); + break; + } + } + if (retval) + break; + } else { + int uncopied; + /* The copy function takes the read lock and handles + locking internally for this case */ + uncopied = copy_from_read_buf(tty, &b, &nr); + uncopied += copy_from_read_buf(tty, &b, &nr); + if (uncopied) { + retval = -EFAULT; + break; + } + } + + /* If there is enough space in the read buffer now, let the + * low-level driver know. We use n_tty_chars_in_buffer() to + * check the buffer, as it now knows about canonical mode. + * Otherwise, if the driver is throttled and the line is + * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode, + * we won't get any more characters. + */ + if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) { + n_tty_set_room(tty); + check_unthrottle(tty); + } + + if (b - buf >= minimum) + break; + if (time) + timeout = time; + } + mutex_unlock(&tty->atomic_read_lock); + remove_wait_queue(&tty->read_wait, &wait); + + if (!waitqueue_active(&tty->read_wait)) + tty->minimum_to_wake = minimum; + + __set_current_state(TASK_RUNNING); + size = b - buf; + if (size) { + retval = size; + if (nr) + clear_bit(TTY_PUSH, &tty->flags); + } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) + goto do_it_again; + + n_tty_set_room(tty); + return retval; +} + +/** + * n_tty_write - write function for tty + * @tty: tty device + * @file: file object + * @buf: userspace buffer pointer + * @nr: size of I/O + * + * Write function of the terminal device. This is serialized with + * respect to other write callers but not to termios changes, reads + * and other such events. Since the receive code will echo characters, + * thus calling driver write methods, the output_lock is used in + * the output processing functions called here as well as in the + * echo processing function to protect the column state and space + * left in the buffer. + * + * This code must be sure never to sleep through a hangup. + * + * Locking: output_lock to protect column state and space left + * (note that the process_output*() functions take this + * lock themselves) + */ + +static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, + const unsigned char *buf, size_t nr) +{ + const unsigned char *b = buf; + DECLARE_WAITQUEUE(wait, current); + int c; + ssize_t retval = 0; + + /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */ + if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) { + retval = tty_check_change(tty); + if (retval) + return retval; + } + + /* Write out any echoed characters that are still pending */ + process_echoes(tty); + + add_wait_queue(&tty->write_wait, &wait); + while (1) { + set_current_state(TASK_INTERRUPTIBLE); + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) { + retval = -EIO; + break; + } + if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { + while (nr > 0) { + ssize_t num = process_output_block(tty, b, nr); + if (num < 0) { + if (num == -EAGAIN) + break; + retval = num; + goto break_out; + } + b += num; + nr -= num; + if (nr == 0) + break; + c = *b; + if (process_output(c, tty) < 0) + break; + b++; nr--; + } + if (tty->ops->flush_chars) + tty->ops->flush_chars(tty); + } else { + while (nr > 0) { + c = tty->ops->write(tty, b, nr); + if (c < 0) { + retval = c; + goto break_out; + } + if (!c) + break; + b += c; + nr -= c; + } + } + if (!nr) + break; + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + schedule(); + } +break_out: + __set_current_state(TASK_RUNNING); + remove_wait_queue(&tty->write_wait, &wait); + if (b - buf != nr && tty->fasync) + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + return (b - buf) ? b - buf : retval; +} + +/** + * n_tty_poll - poll method for N_TTY + * @tty: terminal device + * @file: file accessing it + * @wait: poll table + * + * Called when the line discipline is asked to poll() for data or + * for special events. This code is not serialized with respect to + * other events save open/close. + * + * This code must be sure never to sleep through a hangup. + * Called without the kernel lock held - fine + */ + +static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file, + poll_table *wait) +{ + unsigned int mask = 0; + + poll_wait(file, &tty->read_wait, wait); + poll_wait(file, &tty->write_wait, wait); + if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty))) + mask |= POLLIN | POLLRDNORM; + if (tty->packet && tty->link->ctrl_status) + mask |= POLLPRI | POLLIN | POLLRDNORM; + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) + mask |= POLLHUP; + if (tty_hung_up_p(file)) + mask |= POLLHUP; + if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) { + if (MIN_CHAR(tty) && !TIME_CHAR(tty)) + tty->minimum_to_wake = MIN_CHAR(tty); + else + tty->minimum_to_wake = 1; + } + if (tty->ops->write && !tty_is_writelocked(tty) && + tty_chars_in_buffer(tty) < WAKEUP_CHARS && + tty_write_room(tty) > 0) + mask |= POLLOUT | POLLWRNORM; + return mask; +} + +static unsigned long inq_canon(struct tty_struct *tty) +{ + int nr, head, tail; + + if (!tty->canon_data) + return 0; + head = tty->canon_head; + tail = tty->read_tail; + nr = (head - tail) & (N_TTY_BUF_SIZE-1); + /* Skip EOF-chars.. */ + while (head != tail) { + if (test_bit(tail, tty->read_flags) && + tty->read_buf[tail] == __DISABLED_CHAR) + nr--; + tail = (tail+1) & (N_TTY_BUF_SIZE-1); + } + return nr; +} + +static int n_tty_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + int retval; + + switch (cmd) { + case TIOCOUTQ: + return put_user(tty_chars_in_buffer(tty), (int __user *) arg); + case TIOCINQ: + /* FIXME: Locking */ + retval = tty->read_cnt; + if (L_ICANON(tty)) + retval = inq_canon(tty); + return put_user(retval, (unsigned int __user *) arg); + default: + return n_tty_ioctl_helper(tty, file, cmd, arg); + } +} + +struct tty_ldisc_ops tty_ldisc_N_TTY = { + .magic = TTY_LDISC_MAGIC, + .name = "n_tty", + .open = n_tty_open, + .close = n_tty_close, + .flush_buffer = n_tty_flush_buffer, + .chars_in_buffer = n_tty_chars_in_buffer, + .read = n_tty_read, + .write = n_tty_write, + .ioctl = n_tty_ioctl, + .set_termios = n_tty_set_termios, + .poll = n_tty_poll, + .receive_buf = n_tty_receive_buf, + .write_wakeup = n_tty_write_wakeup +}; + +/** + * n_tty_inherit_ops - inherit N_TTY methods + * @ops: struct tty_ldisc_ops where to save N_TTY methods + * + * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY + * methods. + */ + +void n_tty_inherit_ops(struct tty_ldisc_ops *ops) +{ + *ops = tty_ldisc_N_TTY; + ops->owner = NULL; + ops->refcount = ops->flags = 0; +} +EXPORT_SYMBOL_GPL(n_tty_inherit_ops); diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c new file mode 100644 index 00000000000..923a4858550 --- /dev/null +++ b/drivers/tty/pty.c @@ -0,0 +1,777 @@ +/* + * linux/drivers/char/pty.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * Added support for a Unix98-style ptmx device. + * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 + * + * When reading this code see also fs/devpts. In particular note that the + * driver_data field is used by the devpts side as a binding to the devpts + * inode. + */ + +#include <linux/module.h> + +#include <linux/errno.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/string.h> +#include <linux/major.h> +#include <linux/mm.h> +#include <linux/init.h> +#include <linux/smp_lock.h> +#include <linux/sysctl.h> +#include <linux/device.h> +#include <linux/uaccess.h> +#include <linux/bitops.h> +#include <linux/devpts_fs.h> +#include <linux/slab.h> + +#include <asm/system.h> + +#ifdef CONFIG_UNIX98_PTYS +static struct tty_driver *ptm_driver; +static struct tty_driver *pts_driver; +#endif + +static void pty_close(struct tty_struct *tty, struct file *filp) +{ + BUG_ON(!tty); + if (tty->driver->subtype == PTY_TYPE_MASTER) + WARN_ON(tty->count > 1); + else { + if (tty->count > 2) + return; + } + wake_up_interruptible(&tty->read_wait); + wake_up_interruptible(&tty->write_wait); + tty->packet = 0; + if (!tty->link) + return; + tty->link->packet = 0; + set_bit(TTY_OTHER_CLOSED, &tty->link->flags); + wake_up_interruptible(&tty->link->read_wait); + wake_up_interruptible(&tty->link->write_wait); + if (tty->driver->subtype == PTY_TYPE_MASTER) { + set_bit(TTY_OTHER_CLOSED, &tty->flags); +#ifdef CONFIG_UNIX98_PTYS + if (tty->driver == ptm_driver) + devpts_pty_kill(tty->link); +#endif + tty_unlock(); + tty_vhangup(tty->link); + tty_lock(); + } +} + +/* + * The unthrottle routine is called by the line discipline to signal + * that it can receive more characters. For PTY's, the TTY_THROTTLED + * flag is always set, to force the line discipline to always call the + * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE + * characters in the queue. This is necessary since each time this + * happens, we need to wake up any sleeping processes that could be + * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() + * for the pty buffer to be drained. + */ +static void pty_unthrottle(struct tty_struct *tty) +{ + tty_wakeup(tty->link); + set_bit(TTY_THROTTLED, &tty->flags); +} + +/** + * pty_space - report space left for writing + * @to: tty we are writing into + * + * The tty buffers allow 64K but we sneak a peak and clip at 8K this + * allows a lot of overspill room for echo and other fun messes to + * be handled properly + */ + +static int pty_space(struct tty_struct *to) +{ + int n = 8192 - to->buf.memory_used; + if (n < 0) + return 0; + return n; +} + +/** + * pty_write - write to a pty + * @tty: the tty we write from + * @buf: kernel buffer of data + * @count: bytes to write + * + * Our "hardware" write method. Data is coming from the ldisc which + * may be in a non sleeping state. We simply throw this at the other + * end of the link as if we were an IRQ handler receiving stuff for + * the other side of the pty/tty pair. + */ + +static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) +{ + struct tty_struct *to = tty->link; + + if (tty->stopped) + return 0; + + if (c > 0) { + /* Stuff the data into the input queue of the other end */ + c = tty_insert_flip_string(to, buf, c); + /* And shovel */ + if (c) { + tty_flip_buffer_push(to); + tty_wakeup(tty); + } + } + return c; +} + +/** + * pty_write_room - write space + * @tty: tty we are writing from + * + * Report how many bytes the ldisc can send into the queue for + * the other device. + */ + +static int pty_write_room(struct tty_struct *tty) +{ + if (tty->stopped) + return 0; + return pty_space(tty->link); +} + +/** + * pty_chars_in_buffer - characters currently in our tx queue + * @tty: our tty + * + * Report how much we have in the transmit queue. As everything is + * instantly at the other end this is easy to implement. + */ + +static int pty_chars_in_buffer(struct tty_struct *tty) +{ + return 0; +} + +/* Set the lock flag on a pty */ +static int pty_set_lock(struct tty_struct *tty, int __user *arg) +{ + int val; + if (get_user(val, arg)) + return -EFAULT; + if (val) + set_bit(TTY_PTY_LOCK, &tty->flags); + else + clear_bit(TTY_PTY_LOCK, &tty->flags); + return 0; +} + +/* Send a signal to the slave */ +static int pty_signal(struct tty_struct *tty, int sig) +{ + unsigned long flags; + struct pid *pgrp; + + if (tty->link) { + spin_lock_irqsave(&tty->link->ctrl_lock, flags); + pgrp = get_pid(tty->link->pgrp); + spin_unlock_irqrestore(&tty->link->ctrl_lock, flags); + + kill_pgrp(pgrp, sig, 1); + put_pid(pgrp); + } + return 0; +} + +static void pty_flush_buffer(struct tty_struct *tty) +{ + struct tty_struct *to = tty->link; + unsigned long flags; + + if (!to) + return; + /* tty_buffer_flush(to); FIXME */ + if (to->packet) { + spin_lock_irqsave(&tty->ctrl_lock, flags); + tty->ctrl_status |= TIOCPKT_FLUSHWRITE; + wake_up_interruptible(&to->read_wait); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + } +} + +static int pty_open(struct tty_struct *tty, struct file *filp) +{ + int retval = -ENODEV; + + if (!tty || !tty->link) + goto out; + + retval = -EIO; + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) + goto out; + if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) + goto out; + if (tty->link->count != 1) + goto out; + + clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); + set_bit(TTY_THROTTLED, &tty->flags); + retval = 0; +out: + return retval; +} + +static void pty_set_termios(struct tty_struct *tty, + struct ktermios *old_termios) +{ + tty->termios->c_cflag &= ~(CSIZE | PARENB); + tty->termios->c_cflag |= (CS8 | CREAD); +} + +/** + * pty_do_resize - resize event + * @tty: tty being resized + * @ws: window size being set. + * + * Update the termios variables and send the necessary signals to + * peform a terminal resize correctly + */ + +int pty_resize(struct tty_struct *tty, struct winsize *ws) +{ + struct pid *pgrp, *rpgrp; + unsigned long flags; + struct tty_struct *pty = tty->link; + + /* For a PTY we need to lock the tty side */ + mutex_lock(&tty->termios_mutex); + if (!memcmp(ws, &tty->winsize, sizeof(*ws))) + goto done; + + /* Get the PID values and reference them so we can + avoid holding the tty ctrl lock while sending signals. + We need to lock these individually however. */ + + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + spin_lock_irqsave(&pty->ctrl_lock, flags); + rpgrp = get_pid(pty->pgrp); + spin_unlock_irqrestore(&pty->ctrl_lock, flags); + + if (pgrp) + kill_pgrp(pgrp, SIGWINCH, 1); + if (rpgrp != pgrp && rpgrp) + kill_pgrp(rpgrp, SIGWINCH, 1); + + put_pid(pgrp); + put_pid(rpgrp); + + tty->winsize = *ws; + pty->winsize = *ws; /* Never used so will go away soon */ +done: + mutex_unlock(&tty->termios_mutex); + return 0; +} + +/* Traditional BSD devices */ +#ifdef CONFIG_LEGACY_PTYS + +static int pty_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct tty_struct *o_tty; + int idx = tty->index; + int retval; + + o_tty = alloc_tty_struct(); + if (!o_tty) + return -ENOMEM; + if (!try_module_get(driver->other->owner)) { + /* This cannot in fact currently happen */ + free_tty_struct(o_tty); + return -ENOMEM; + } + initialize_tty_struct(o_tty, driver->other, idx); + + /* We always use new tty termios data so we can do this + the easy way .. */ + retval = tty_init_termios(tty); + if (retval) + goto free_mem_out; + + retval = tty_init_termios(o_tty); + if (retval) { + tty_free_termios(tty); + goto free_mem_out; + } + + /* + * Everything allocated ... set up the o_tty structure. + */ + driver->other->ttys[idx] = o_tty; + tty_driver_kref_get(driver->other); + if (driver->subtype == PTY_TYPE_MASTER) + o_tty->count++; + /* Establish the links in both directions */ + tty->link = o_tty; + o_tty->link = tty; + + tty_driver_kref_get(driver); + tty->count++; + driver->ttys[idx] = tty; + return 0; +free_mem_out: + module_put(o_tty->driver->owner); + free_tty_struct(o_tty); + return -ENOMEM; +} + +static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ + return pty_set_lock(tty, (int __user *) arg); + case TIOCSIG: /* Send signal to other side of pty */ + return pty_signal(tty, (int) arg); + } + return -ENOIOCTLCMD; +} + +static int legacy_count = CONFIG_LEGACY_PTY_COUNT; +module_param(legacy_count, int, 0); + +/* + * The master side of a pty can do TIOCSPTLCK and thus + * has pty_bsd_ioctl. + */ +static const struct tty_operations master_pty_ops_bsd = { + .install = pty_install, + .open = pty_open, + .close = pty_close, + .write = pty_write, + .write_room = pty_write_room, + .flush_buffer = pty_flush_buffer, + .chars_in_buffer = pty_chars_in_buffer, + .unthrottle = pty_unthrottle, + .set_termios = pty_set_termios, + .ioctl = pty_bsd_ioctl, + .resize = pty_resize +}; + +static const struct tty_operations slave_pty_ops_bsd = { + .install = pty_install, + .open = pty_open, + .close = pty_close, + .write = pty_write, + .write_room = pty_write_room, + .flush_buffer = pty_flush_buffer, + .chars_in_buffer = pty_chars_in_buffer, + .unthrottle = pty_unthrottle, + .set_termios = pty_set_termios, + .resize = pty_resize +}; + +static void __init legacy_pty_init(void) +{ + struct tty_driver *pty_driver, *pty_slave_driver; + + if (legacy_count <= 0) + return; + + pty_driver = alloc_tty_driver(legacy_count); + if (!pty_driver) + panic("Couldn't allocate pty driver"); + + pty_slave_driver = alloc_tty_driver(legacy_count); + if (!pty_slave_driver) + panic("Couldn't allocate pty slave driver"); + + pty_driver->owner = THIS_MODULE; + pty_driver->driver_name = "pty_master"; + pty_driver->name = "pty"; + pty_driver->major = PTY_MASTER_MAJOR; + pty_driver->minor_start = 0; + pty_driver->type = TTY_DRIVER_TYPE_PTY; + pty_driver->subtype = PTY_TYPE_MASTER; + pty_driver->init_termios = tty_std_termios; + pty_driver->init_termios.c_iflag = 0; + pty_driver->init_termios.c_oflag = 0; + pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; + pty_driver->init_termios.c_lflag = 0; + pty_driver->init_termios.c_ispeed = 38400; + pty_driver->init_termios.c_ospeed = 38400; + pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW; + pty_driver->other = pty_slave_driver; + tty_set_operations(pty_driver, &master_pty_ops_bsd); + + pty_slave_driver->owner = THIS_MODULE; + pty_slave_driver->driver_name = "pty_slave"; + pty_slave_driver->name = "ttyp"; + pty_slave_driver->major = PTY_SLAVE_MAJOR; + pty_slave_driver->minor_start = 0; + pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; + pty_slave_driver->subtype = PTY_TYPE_SLAVE; + pty_slave_driver->init_termios = tty_std_termios; + pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; + pty_slave_driver->init_termios.c_ispeed = 38400; + pty_slave_driver->init_termios.c_ospeed = 38400; + pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW; + pty_slave_driver->other = pty_driver; + tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); + + if (tty_register_driver(pty_driver)) + panic("Couldn't register pty driver"); + if (tty_register_driver(pty_slave_driver)) + panic("Couldn't register pty slave driver"); +} +#else +static inline void legacy_pty_init(void) { } +#endif + +/* Unix98 devices */ +#ifdef CONFIG_UNIX98_PTYS +/* + * sysctl support for setting limits on the number of Unix98 ptys allocated. + * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly. + */ +int pty_limit = NR_UNIX98_PTY_DEFAULT; +static int pty_limit_min; +static int pty_limit_max = NR_UNIX98_PTY_MAX; +static int pty_count; + +static struct cdev ptmx_cdev; + +static struct ctl_table pty_table[] = { + { + .procname = "max", + .maxlen = sizeof(int), + .mode = 0644, + .data = &pty_limit, + .proc_handler = proc_dointvec_minmax, + .extra1 = &pty_limit_min, + .extra2 = &pty_limit_max, + }, { + .procname = "nr", + .maxlen = sizeof(int), + .mode = 0444, + .data = &pty_count, + .proc_handler = proc_dointvec, + }, + {} +}; + +static struct ctl_table pty_kern_table[] = { + { + .procname = "pty", + .mode = 0555, + .child = pty_table, + }, + {} +}; + +static struct ctl_table pty_root_table[] = { + { + .procname = "kernel", + .mode = 0555, + .child = pty_kern_table, + }, + {} +}; + + +static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ + return pty_set_lock(tty, (int __user *)arg); + case TIOCGPTN: /* Get PT Number */ + return put_user(tty->index, (unsigned int __user *)arg); + case TIOCSIG: /* Send signal to other side of pty */ + return pty_signal(tty, (int) arg); + } + + return -ENOIOCTLCMD; +} + +/** + * ptm_unix98_lookup - find a pty master + * @driver: ptm driver + * @idx: tty index + * + * Look up a pty master device. Called under the tty_mutex for now. + * This provides our locking. + */ + +static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, + struct inode *ptm_inode, int idx) +{ + struct tty_struct *tty = devpts_get_tty(ptm_inode, idx); + if (tty) + tty = tty->link; + return tty; +} + +/** + * pts_unix98_lookup - find a pty slave + * @driver: pts driver + * @idx: tty index + * + * Look up a pty master device. Called under the tty_mutex for now. + * This provides our locking. + */ + +static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, + struct inode *pts_inode, int idx) +{ + struct tty_struct *tty = devpts_get_tty(pts_inode, idx); + /* Master must be open before slave */ + if (!tty) + return ERR_PTR(-EIO); + return tty; +} + +static void pty_unix98_shutdown(struct tty_struct *tty) +{ + /* We have our own method as we don't use the tty index */ + kfree(tty->termios); +} + +/* We have no need to install and remove our tty objects as devpts does all + the work for us */ + +static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct tty_struct *o_tty; + int idx = tty->index; + + o_tty = alloc_tty_struct(); + if (!o_tty) + return -ENOMEM; + if (!try_module_get(driver->other->owner)) { + /* This cannot in fact currently happen */ + free_tty_struct(o_tty); + return -ENOMEM; + } + initialize_tty_struct(o_tty, driver->other, idx); + + tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); + if (tty->termios == NULL) + goto free_mem_out; + *tty->termios = driver->init_termios; + tty->termios_locked = tty->termios + 1; + + o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); + if (o_tty->termios == NULL) + goto free_mem_out; + *o_tty->termios = driver->other->init_termios; + o_tty->termios_locked = o_tty->termios + 1; + + tty_driver_kref_get(driver->other); + if (driver->subtype == PTY_TYPE_MASTER) + o_tty->count++; + /* Establish the links in both directions */ + tty->link = o_tty; + o_tty->link = tty; + /* + * All structures have been allocated, so now we install them. + * Failures after this point use release_tty to clean up, so + * there's no need to null out the local pointers. + */ + tty_driver_kref_get(driver); + tty->count++; + pty_count++; + return 0; +free_mem_out: + kfree(o_tty->termios); + module_put(o_tty->driver->owner); + free_tty_struct(o_tty); + kfree(tty->termios); + return -ENOMEM; +} + +static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) +{ + pty_count--; +} + +static const struct tty_operations ptm_unix98_ops = { + .lookup = ptm_unix98_lookup, + .install = pty_unix98_install, + .remove = pty_unix98_remove, + .open = pty_open, + .close = pty_close, + .write = pty_write, + .write_room = pty_write_room, + .flush_buffer = pty_flush_buffer, + .chars_in_buffer = pty_chars_in_buffer, + .unthrottle = pty_unthrottle, + .set_termios = pty_set_termios, + .ioctl = pty_unix98_ioctl, + .shutdown = pty_unix98_shutdown, + .resize = pty_resize +}; + +static const struct tty_operations pty_unix98_ops = { + .lookup = pts_unix98_lookup, + .install = pty_unix98_install, + .remove = pty_unix98_remove, + .open = pty_open, + .close = pty_close, + .write = pty_write, + .write_room = pty_write_room, + .flush_buffer = pty_flush_buffer, + .chars_in_buffer = pty_chars_in_buffer, + .unthrottle = pty_unthrottle, + .set_termios = pty_set_termios, + .shutdown = pty_unix98_shutdown +}; + +/** + * ptmx_open - open a unix 98 pty master + * @inode: inode of device file + * @filp: file pointer to tty + * + * Allocate a unix98 pty master device from the ptmx driver. + * + * Locking: tty_mutex protects the init_dev work. tty->count should + * protect the rest. + * allocated_ptys_lock handles the list of free pty numbers + */ + +static int ptmx_open(struct inode *inode, struct file *filp) +{ + struct tty_struct *tty; + int retval; + int index; + + nonseekable_open(inode, filp); + + /* find a device that is not in use. */ + tty_lock(); + index = devpts_new_index(inode); + tty_unlock(); + if (index < 0) + return index; + + mutex_lock(&tty_mutex); + tty_lock(); + tty = tty_init_dev(ptm_driver, index, 1); + mutex_unlock(&tty_mutex); + + if (IS_ERR(tty)) { + retval = PTR_ERR(tty); + goto out; + } + + set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ + + retval = tty_add_file(tty, filp); + if (retval) + goto out; + + retval = devpts_pty_new(inode, tty->link); + if (retval) + goto out1; + + retval = ptm_driver->ops->open(tty, filp); + if (retval) + goto out2; +out1: + tty_unlock(); + return retval; +out2: + tty_unlock(); + tty_release(inode, filp); + return retval; +out: + devpts_kill_index(inode, index); + tty_unlock(); + return retval; +} + +static struct file_operations ptmx_fops; + +static void __init unix98_pty_init(void) +{ + ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); + if (!ptm_driver) + panic("Couldn't allocate Unix98 ptm driver"); + pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); + if (!pts_driver) + panic("Couldn't allocate Unix98 pts driver"); + + ptm_driver->owner = THIS_MODULE; + ptm_driver->driver_name = "pty_master"; + ptm_driver->name = "ptm"; + ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; + ptm_driver->minor_start = 0; + ptm_driver->type = TTY_DRIVER_TYPE_PTY; + ptm_driver->subtype = PTY_TYPE_MASTER; + ptm_driver->init_termios = tty_std_termios; + ptm_driver->init_termios.c_iflag = 0; + ptm_driver->init_termios.c_oflag = 0; + ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; + ptm_driver->init_termios.c_lflag = 0; + ptm_driver->init_termios.c_ispeed = 38400; + ptm_driver->init_termios.c_ospeed = 38400; + ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; + ptm_driver->other = pts_driver; + tty_set_operations(ptm_driver, &ptm_unix98_ops); + + pts_driver->owner = THIS_MODULE; + pts_driver->driver_name = "pty_slave"; + pts_driver->name = "pts"; + pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; + pts_driver->minor_start = 0; + pts_driver->type = TTY_DRIVER_TYPE_PTY; + pts_driver->subtype = PTY_TYPE_SLAVE; + pts_driver->init_termios = tty_std_termios; + pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; + pts_driver->init_termios.c_ispeed = 38400; + pts_driver->init_termios.c_ospeed = 38400; + pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; + pts_driver->other = ptm_driver; + tty_set_operations(pts_driver, &pty_unix98_ops); + + if (tty_register_driver(ptm_driver)) + panic("Couldn't register Unix98 ptm driver"); + if (tty_register_driver(pts_driver)) + panic("Couldn't register Unix98 pts driver"); + + register_sysctl_table(pty_root_table); + + /* Now create the /dev/ptmx special device */ + tty_default_fops(&ptmx_fops); + ptmx_fops.open = ptmx_open; + + cdev_init(&ptmx_cdev, &ptmx_fops); + if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || + register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) + panic("Couldn't register /dev/ptmx driver\n"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); +} + +#else +static inline void unix98_pty_init(void) { } +#endif + +static int __init pty_init(void) +{ + legacy_pty_init(); + unix98_pty_init(); + return 0; +} +module_init(pty_init); diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c new file mode 100644 index 00000000000..eaa5d3efa79 --- /dev/null +++ b/drivers/tty/sysrq.c @@ -0,0 +1,811 @@ +/* + * Linux Magic System Request Key Hacks + * + * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> + * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> + * + * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> + * overhauled to use key registration + * based upon discusions in irc://irc.openprojects.net/#kernelnewbies + * + * Copyright (c) 2010 Dmitry Torokhov + * Input handler conversion + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/mm.h> +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/kdev_t.h> +#include <linux/major.h> +#include <linux/reboot.h> +#include <linux/sysrq.h> +#include <linux/kbd_kern.h> +#include <linux/proc_fs.h> +#include <linux/nmi.h> +#include <linux/quotaops.h> +#include <linux/perf_event.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/suspend.h> +#include <linux/writeback.h> +#include <linux/buffer_head.h> /* for fsync_bdev() */ +#include <linux/swap.h> +#include <linux/spinlock.h> +#include <linux/vt_kern.h> +#include <linux/workqueue.h> +#include <linux/hrtimer.h> +#include <linux/oom.h> +#include <linux/slab.h> +#include <linux/input.h> + +#include <asm/ptrace.h> +#include <asm/irq_regs.h> + +/* Whether we react on sysrq keys or just ignore them */ +static int __read_mostly sysrq_enabled = 1; +static bool __read_mostly sysrq_always_enabled; + +static bool sysrq_on(void) +{ + return sysrq_enabled || sysrq_always_enabled; +} + +/* + * A value of 1 means 'all', other nonzero values are an op mask: + */ +static bool sysrq_on_mask(int mask) +{ + return sysrq_always_enabled || + sysrq_enabled == 1 || + (sysrq_enabled & mask); +} + +static int __init sysrq_always_enabled_setup(char *str) +{ + sysrq_always_enabled = true; + pr_info("sysrq always enabled.\n"); + + return 1; +} + +__setup("sysrq_always_enabled", sysrq_always_enabled_setup); + + +static void sysrq_handle_loglevel(int key) +{ + int i; + + i = key - '0'; + console_loglevel = 7; + printk("Loglevel set to %d\n", i); + console_loglevel = i; +} +static struct sysrq_key_op sysrq_loglevel_op = { + .handler = sysrq_handle_loglevel, + .help_msg = "loglevel(0-9)", + .action_msg = "Changing Loglevel", + .enable_mask = SYSRQ_ENABLE_LOG, +}; + +#ifdef CONFIG_VT +static void sysrq_handle_SAK(int key) +{ + struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; + schedule_work(SAK_work); +} +static struct sysrq_key_op sysrq_SAK_op = { + .handler = sysrq_handle_SAK, + .help_msg = "saK", + .action_msg = "SAK", + .enable_mask = SYSRQ_ENABLE_KEYBOARD, +}; +#else +#define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) +#endif + +#ifdef CONFIG_VT +static void sysrq_handle_unraw(int key) +{ + struct kbd_struct *kbd = &kbd_table[fg_console]; + + if (kbd) + kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE; +} +static struct sysrq_key_op sysrq_unraw_op = { + .handler = sysrq_handle_unraw, + .help_msg = "unRaw", + .action_msg = "Keyboard mode set to system default", + .enable_mask = SYSRQ_ENABLE_KEYBOARD, +}; +#else +#define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) +#endif /* CONFIG_VT */ + +static void sysrq_handle_crash(int key) +{ + char *killer = NULL; + + panic_on_oops = 1; /* force panic */ + wmb(); + *killer = 1; +} +static struct sysrq_key_op sysrq_crash_op = { + .handler = sysrq_handle_crash, + .help_msg = "Crash", + .action_msg = "Trigger a crash", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +static void sysrq_handle_reboot(int key) +{ + lockdep_off(); + local_irq_enable(); + emergency_restart(); +} +static struct sysrq_key_op sysrq_reboot_op = { + .handler = sysrq_handle_reboot, + .help_msg = "reBoot", + .action_msg = "Resetting", + .enable_mask = SYSRQ_ENABLE_BOOT, +}; + +static void sysrq_handle_sync(int key) +{ + emergency_sync(); +} +static struct sysrq_key_op sysrq_sync_op = { + .handler = sysrq_handle_sync, + .help_msg = "Sync", + .action_msg = "Emergency Sync", + .enable_mask = SYSRQ_ENABLE_SYNC, +}; + +static void sysrq_handle_show_timers(int key) +{ + sysrq_timer_list_show(); +} + +static struct sysrq_key_op sysrq_show_timers_op = { + .handler = sysrq_handle_show_timers, + .help_msg = "show-all-timers(Q)", + .action_msg = "Show clockevent devices & pending hrtimers (no others)", +}; + +static void sysrq_handle_mountro(int key) +{ + emergency_remount(); +} +static struct sysrq_key_op sysrq_mountro_op = { + .handler = sysrq_handle_mountro, + .help_msg = "Unmount", + .action_msg = "Emergency Remount R/O", + .enable_mask = SYSRQ_ENABLE_REMOUNT, +}; + +#ifdef CONFIG_LOCKDEP +static void sysrq_handle_showlocks(int key) +{ + debug_show_all_locks(); +} + +static struct sysrq_key_op sysrq_showlocks_op = { + .handler = sysrq_handle_showlocks, + .help_msg = "show-all-locks(D)", + .action_msg = "Show Locks Held", +}; +#else +#define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) +#endif + +#ifdef CONFIG_SMP +static DEFINE_SPINLOCK(show_lock); + +static void showacpu(void *dummy) +{ + unsigned long flags; + + /* Idle CPUs have no interesting backtrace. */ + if (idle_cpu(smp_processor_id())) + return; + + spin_lock_irqsave(&show_lock, flags); + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_stack(NULL, NULL); + spin_unlock_irqrestore(&show_lock, flags); +} + +static void sysrq_showregs_othercpus(struct work_struct *dummy) +{ + smp_call_function(showacpu, NULL, 0); +} + +static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); + +static void sysrq_handle_showallcpus(int key) +{ + /* + * Fall back to the workqueue based printing if the + * backtrace printing did not succeed or the + * architecture has no support for it: + */ + if (!trigger_all_cpu_backtrace()) { + struct pt_regs *regs = get_irq_regs(); + + if (regs) { + printk(KERN_INFO "CPU%d:\n", smp_processor_id()); + show_regs(regs); + } + schedule_work(&sysrq_showallcpus); + } +} + +static struct sysrq_key_op sysrq_showallcpus_op = { + .handler = sysrq_handle_showallcpus, + .help_msg = "show-backtrace-all-active-cpus(L)", + .action_msg = "Show backtrace of all active CPUs", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; +#endif + +static void sysrq_handle_showregs(int key) +{ + struct pt_regs *regs = get_irq_regs(); + if (regs) + show_regs(regs); + perf_event_print_debug(); +} +static struct sysrq_key_op sysrq_showregs_op = { + .handler = sysrq_handle_showregs, + .help_msg = "show-registers(P)", + .action_msg = "Show Regs", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +static void sysrq_handle_showstate(int key) +{ + show_state(); +} +static struct sysrq_key_op sysrq_showstate_op = { + .handler = sysrq_handle_showstate, + .help_msg = "show-task-states(T)", + .action_msg = "Show State", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +static void sysrq_handle_showstate_blocked(int key) +{ + show_state_filter(TASK_UNINTERRUPTIBLE); +} +static struct sysrq_key_op sysrq_showstate_blocked_op = { + .handler = sysrq_handle_showstate_blocked, + .help_msg = "show-blocked-tasks(W)", + .action_msg = "Show Blocked State", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +#ifdef CONFIG_TRACING +#include <linux/ftrace.h> + +static void sysrq_ftrace_dump(int key) +{ + ftrace_dump(DUMP_ALL); +} +static struct sysrq_key_op sysrq_ftrace_dump_op = { + .handler = sysrq_ftrace_dump, + .help_msg = "dump-ftrace-buffer(Z)", + .action_msg = "Dump ftrace buffer", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; +#else +#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) +#endif + +static void sysrq_handle_showmem(int key) +{ + show_mem(); +} +static struct sysrq_key_op sysrq_showmem_op = { + .handler = sysrq_handle_showmem, + .help_msg = "show-memory-usage(M)", + .action_msg = "Show Memory", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + +/* + * Signal sysrq helper function. Sends a signal to all user processes. + */ +static void send_sig_all(int sig) +{ + struct task_struct *p; + + for_each_process(p) { + if (p->mm && !is_global_init(p)) + /* Not swapper, init nor kernel thread */ + force_sig(sig, p); + } +} + +static void sysrq_handle_term(int key) +{ + send_sig_all(SIGTERM); + console_loglevel = 8; +} +static struct sysrq_key_op sysrq_term_op = { + .handler = sysrq_handle_term, + .help_msg = "terminate-all-tasks(E)", + .action_msg = "Terminate All Tasks", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; + +static void moom_callback(struct work_struct *ignored) +{ + out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL); +} + +static DECLARE_WORK(moom_work, moom_callback); + +static void sysrq_handle_moom(int key) +{ + schedule_work(&moom_work); +} +static struct sysrq_key_op sysrq_moom_op = { + .handler = sysrq_handle_moom, + .help_msg = "memory-full-oom-kill(F)", + .action_msg = "Manual OOM execution", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; + +#ifdef CONFIG_BLOCK +static void sysrq_handle_thaw(int key) +{ + emergency_thaw_all(); +} +static struct sysrq_key_op sysrq_thaw_op = { + .handler = sysrq_handle_thaw, + .help_msg = "thaw-filesystems(J)", + .action_msg = "Emergency Thaw of all frozen filesystems", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; +#endif + +static void sysrq_handle_kill(int key) +{ + send_sig_all(SIGKILL); + console_loglevel = 8; +} +static struct sysrq_key_op sysrq_kill_op = { + .handler = sysrq_handle_kill, + .help_msg = "kill-all-tasks(I)", + .action_msg = "Kill All Tasks", + .enable_mask = SYSRQ_ENABLE_SIGNAL, +}; + +static void sysrq_handle_unrt(int key) +{ + normalize_rt_tasks(); +} +static struct sysrq_key_op sysrq_unrt_op = { + .handler = sysrq_handle_unrt, + .help_msg = "nice-all-RT-tasks(N)", + .action_msg = "Nice All RT Tasks", + .enable_mask = SYSRQ_ENABLE_RTNICE, +}; + +/* Key Operations table and lock */ +static DEFINE_SPINLOCK(sysrq_key_table_lock); + +static struct sysrq_key_op *sysrq_key_table[36] = { + &sysrq_loglevel_op, /* 0 */ + &sysrq_loglevel_op, /* 1 */ + &sysrq_loglevel_op, /* 2 */ + &sysrq_loglevel_op, /* 3 */ + &sysrq_loglevel_op, /* 4 */ + &sysrq_loglevel_op, /* 5 */ + &sysrq_loglevel_op, /* 6 */ + &sysrq_loglevel_op, /* 7 */ + &sysrq_loglevel_op, /* 8 */ + &sysrq_loglevel_op, /* 9 */ + + /* + * a: Don't use for system provided sysrqs, it is handled specially on + * sparc and will never arrive. + */ + NULL, /* a */ + &sysrq_reboot_op, /* b */ + &sysrq_crash_op, /* c & ibm_emac driver debug */ + &sysrq_showlocks_op, /* d */ + &sysrq_term_op, /* e */ + &sysrq_moom_op, /* f */ + /* g: May be registered for the kernel debugger */ + NULL, /* g */ + NULL, /* h - reserved for help */ + &sysrq_kill_op, /* i */ +#ifdef CONFIG_BLOCK + &sysrq_thaw_op, /* j */ +#else + NULL, /* j */ +#endif + &sysrq_SAK_op, /* k */ +#ifdef CONFIG_SMP + &sysrq_showallcpus_op, /* l */ +#else + NULL, /* l */ +#endif + &sysrq_showmem_op, /* m */ + &sysrq_unrt_op, /* n */ + /* o: This will often be registered as 'Off' at init time */ + NULL, /* o */ + &sysrq_showregs_op, /* p */ + &sysrq_show_timers_op, /* q */ + &sysrq_unraw_op, /* r */ + &sysrq_sync_op, /* s */ + &sysrq_showstate_op, /* t */ + &sysrq_mountro_op, /* u */ + /* v: May be registered for frame buffer console restore */ + NULL, /* v */ + &sysrq_showstate_blocked_op, /* w */ + /* x: May be registered on ppc/powerpc for xmon */ + NULL, /* x */ + /* y: May be registered on sparc64 for global register dump */ + NULL, /* y */ + &sysrq_ftrace_dump_op, /* z */ +}; + +/* key2index calculation, -1 on invalid index */ +static int sysrq_key_table_key2index(int key) +{ + int retval; + + if ((key >= '0') && (key <= '9')) + retval = key - '0'; + else if ((key >= 'a') && (key <= 'z')) + retval = key + 10 - 'a'; + else + retval = -1; + return retval; +} + +/* + * get and put functions for the table, exposed to modules. + */ +struct sysrq_key_op *__sysrq_get_key_op(int key) +{ + struct sysrq_key_op *op_p = NULL; + int i; + + i = sysrq_key_table_key2index(key); + if (i != -1) + op_p = sysrq_key_table[i]; + + return op_p; +} + +static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) +{ + int i = sysrq_key_table_key2index(key); + + if (i != -1) + sysrq_key_table[i] = op_p; +} + +void __handle_sysrq(int key, bool check_mask) +{ + struct sysrq_key_op *op_p; + int orig_log_level; + int i; + unsigned long flags; + + spin_lock_irqsave(&sysrq_key_table_lock, flags); + /* + * Raise the apparent loglevel to maximum so that the sysrq header + * is shown to provide the user with positive feedback. We do not + * simply emit this at KERN_EMERG as that would change message + * routing in the consumers of /proc/kmsg. + */ + orig_log_level = console_loglevel; + console_loglevel = 7; + printk(KERN_INFO "SysRq : "); + + op_p = __sysrq_get_key_op(key); + if (op_p) { + /* + * Should we check for enabled operations (/proc/sysrq-trigger + * should not) and is the invoked operation enabled? + */ + if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { + printk("%s\n", op_p->action_msg); + console_loglevel = orig_log_level; + op_p->handler(key); + } else { + printk("This sysrq operation is disabled.\n"); + } + } else { + printk("HELP : "); + /* Only print the help msg once per handler */ + for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { + if (sysrq_key_table[i]) { + int j; + + for (j = 0; sysrq_key_table[i] != + sysrq_key_table[j]; j++) + ; + if (j != i) + continue; + printk("%s ", sysrq_key_table[i]->help_msg); + } + } + printk("\n"); + console_loglevel = orig_log_level; + } + spin_unlock_irqrestore(&sysrq_key_table_lock, flags); +} + +void handle_sysrq(int key) +{ + if (sysrq_on()) + __handle_sysrq(key, true); +} +EXPORT_SYMBOL(handle_sysrq); + +#ifdef CONFIG_INPUT + +/* Simple translation table for the SysRq keys */ +static const unsigned char sysrq_xlate[KEY_MAX + 1] = + "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ + "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ + "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ + "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ + "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ + "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ + "\r\000/"; /* 0x60 - 0x6f */ + +static bool sysrq_down; +static int sysrq_alt_use; +static int sysrq_alt; +static DEFINE_SPINLOCK(sysrq_event_lock); + +static bool sysrq_filter(struct input_handle *handle, unsigned int type, + unsigned int code, int value) +{ + bool suppress; + + /* We are called with interrupts disabled, just take the lock */ + spin_lock(&sysrq_event_lock); + + if (type != EV_KEY) + goto out; + + switch (code) { + + case KEY_LEFTALT: + case KEY_RIGHTALT: + if (value) + sysrq_alt = code; + else { + if (sysrq_down && code == sysrq_alt_use) + sysrq_down = false; + + sysrq_alt = 0; + } + break; + + case KEY_SYSRQ: + if (value == 1 && sysrq_alt) { + sysrq_down = true; + sysrq_alt_use = sysrq_alt; + } + break; + + default: + if (sysrq_down && value && value != 2) + __handle_sysrq(sysrq_xlate[code], true); + break; + } + +out: + suppress = sysrq_down; + spin_unlock(&sysrq_event_lock); + + return suppress; +} + +static int sysrq_connect(struct input_handler *handler, + struct input_dev *dev, + const struct input_device_id *id) +{ + struct input_handle *handle; + int error; + + sysrq_down = false; + sysrq_alt = 0; + + handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); + if (!handle) + return -ENOMEM; + + handle->dev = dev; + handle->handler = handler; + handle->name = "sysrq"; + + error = input_register_handle(handle); + if (error) { + pr_err("Failed to register input sysrq handler, error %d\n", + error); + goto err_free; + } + + error = input_open_device(handle); + if (error) { + pr_err("Failed to open input device, error %d\n", error); + goto err_unregister; + } + + return 0; + + err_unregister: + input_unregister_handle(handle); + err_free: + kfree(handle); + return error; +} + +static void sysrq_disconnect(struct input_handle *handle) +{ + input_close_device(handle); + input_unregister_handle(handle); + kfree(handle); +} + +/* + * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all + * keyboards have SysRq key predefined and so user may add it to keymap + * later, but we expect all such keyboards to have left alt. + */ +static const struct input_device_id sysrq_ids[] = { + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT | + INPUT_DEVICE_ID_MATCH_KEYBIT, + .evbit = { BIT_MASK(EV_KEY) }, + .keybit = { BIT_MASK(KEY_LEFTALT) }, + }, + { }, +}; + +static struct input_handler sysrq_handler = { + .filter = sysrq_filter, + .connect = sysrq_connect, + .disconnect = sysrq_disconnect, + .name = "sysrq", + .id_table = sysrq_ids, +}; + +static bool sysrq_handler_registered; + +static inline void sysrq_register_handler(void) +{ + int error; + + error = input_register_handler(&sysrq_handler); + if (error) + pr_err("Failed to register input handler, error %d", error); + else + sysrq_handler_registered = true; +} + +static inline void sysrq_unregister_handler(void) +{ + if (sysrq_handler_registered) { + input_unregister_handler(&sysrq_handler); + sysrq_handler_registered = false; + } +} + +#else + +static inline void sysrq_register_handler(void) +{ +} + +static inline void sysrq_unregister_handler(void) +{ +} + +#endif /* CONFIG_INPUT */ + +int sysrq_toggle_support(int enable_mask) +{ + bool was_enabled = sysrq_on(); + + sysrq_enabled = enable_mask; + + if (was_enabled != sysrq_on()) { + if (sysrq_on()) + sysrq_register_handler(); + else + sysrq_unregister_handler(); + } + + return 0; +} + +static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, + struct sysrq_key_op *remove_op_p) +{ + int retval; + unsigned long flags; + + spin_lock_irqsave(&sysrq_key_table_lock, flags); + if (__sysrq_get_key_op(key) == remove_op_p) { + __sysrq_put_key_op(key, insert_op_p); + retval = 0; + } else { + retval = -1; + } + spin_unlock_irqrestore(&sysrq_key_table_lock, flags); + return retval; +} + +int register_sysrq_key(int key, struct sysrq_key_op *op_p) +{ + return __sysrq_swap_key_ops(key, op_p, NULL); +} +EXPORT_SYMBOL(register_sysrq_key); + +int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) +{ + return __sysrq_swap_key_ops(key, NULL, op_p); +} +EXPORT_SYMBOL(unregister_sysrq_key); + +#ifdef CONFIG_PROC_FS +/* + * writing 'C' to /proc/sysrq-trigger is like sysrq-C + */ +static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + if (count) { + char c; + + if (get_user(c, buf)) + return -EFAULT; + __handle_sysrq(c, false); + } + + return count; +} + +static const struct file_operations proc_sysrq_trigger_operations = { + .write = write_sysrq_trigger, + .llseek = noop_llseek, +}; + +static void sysrq_init_procfs(void) +{ + if (!proc_create("sysrq-trigger", S_IWUSR, NULL, + &proc_sysrq_trigger_operations)) + pr_err("Failed to register proc interface\n"); +} + +#else + +static inline void sysrq_init_procfs(void) +{ +} + +#endif /* CONFIG_PROC_FS */ + +static int __init sysrq_init(void) +{ + sysrq_init_procfs(); + + if (sysrq_on()) + sysrq_register_handler(); + + return 0; +} +module_init(sysrq_init); diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c new file mode 100644 index 00000000000..f64582b0f62 --- /dev/null +++ b/drivers/tty/tty_audit.c @@ -0,0 +1,358 @@ +/* + * Creating audit events from TTY input. + * + * Copyright (C) 2007 Red Hat, Inc. All rights reserved. This copyrighted + * material is made available to anyone wishing to use, modify, copy, or + * redistribute it subject to the terms and conditions of the GNU General + * Public License v.2. + * + * Authors: Miloslav Trmac <mitr@redhat.com> + */ + +#include <linux/audit.h> +#include <linux/slab.h> +#include <linux/tty.h> + +struct tty_audit_buf { + atomic_t count; + struct mutex mutex; /* Protects all data below */ + int major, minor; /* The TTY which the data is from */ + unsigned icanon:1; + size_t valid; + unsigned char *data; /* Allocated size N_TTY_BUF_SIZE */ +}; + +static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor, + int icanon) +{ + struct tty_audit_buf *buf; + + buf = kmalloc(sizeof(*buf), GFP_KERNEL); + if (!buf) + goto err; + buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL); + if (!buf->data) + goto err_buf; + atomic_set(&buf->count, 1); + mutex_init(&buf->mutex); + buf->major = major; + buf->minor = minor; + buf->icanon = icanon; + buf->valid = 0; + return buf; + +err_buf: + kfree(buf); +err: + return NULL; +} + +static void tty_audit_buf_free(struct tty_audit_buf *buf) +{ + WARN_ON(buf->valid != 0); + kfree(buf->data); + kfree(buf); +} + +static void tty_audit_buf_put(struct tty_audit_buf *buf) +{ + if (atomic_dec_and_test(&buf->count)) + tty_audit_buf_free(buf); +} + +static void tty_audit_log(const char *description, struct task_struct *tsk, + uid_t loginuid, unsigned sessionid, int major, + int minor, unsigned char *data, size_t size) +{ + struct audit_buffer *ab; + + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY); + if (ab) { + char name[sizeof(tsk->comm)]; + uid_t uid = task_uid(tsk); + + audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u " + "major=%d minor=%d comm=", description, + tsk->pid, uid, loginuid, sessionid, + major, minor); + get_task_comm(name, tsk); + audit_log_untrustedstring(ab, name); + audit_log_format(ab, " data="); + audit_log_n_hex(ab, data, size); + audit_log_end(ab); + } +} + +/** + * tty_audit_buf_push - Push buffered data out + * + * Generate an audit message from the contents of @buf, which is owned by + * @tsk with @loginuid. @buf->mutex must be locked. + */ +static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid, + unsigned int sessionid, + struct tty_audit_buf *buf) +{ + if (buf->valid == 0) + return; + if (audit_enabled == 0) + return; + tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor, + buf->data, buf->valid); + buf->valid = 0; +} + +/** + * tty_audit_buf_push_current - Push buffered data out + * + * Generate an audit message from the contents of @buf, which is owned by + * the current task. @buf->mutex must be locked. + */ +static void tty_audit_buf_push_current(struct tty_audit_buf *buf) +{ + uid_t auid = audit_get_loginuid(current); + unsigned int sessionid = audit_get_sessionid(current); + tty_audit_buf_push(current, auid, sessionid, buf); +} + +/** + * tty_audit_exit - Handle a task exit + * + * Make sure all buffered data is written out and deallocate the buffer. + * Only needs to be called if current->signal->tty_audit_buf != %NULL. + */ +void tty_audit_exit(void) +{ + struct tty_audit_buf *buf; + + spin_lock_irq(¤t->sighand->siglock); + buf = current->signal->tty_audit_buf; + current->signal->tty_audit_buf = NULL; + spin_unlock_irq(¤t->sighand->siglock); + if (!buf) + return; + + mutex_lock(&buf->mutex); + tty_audit_buf_push_current(buf); + mutex_unlock(&buf->mutex); + + tty_audit_buf_put(buf); +} + +/** + * tty_audit_fork - Copy TTY audit state for a new task + * + * Set up TTY audit state in @sig from current. @sig needs no locking. + */ +void tty_audit_fork(struct signal_struct *sig) +{ + spin_lock_irq(¤t->sighand->siglock); + sig->audit_tty = current->signal->audit_tty; + spin_unlock_irq(¤t->sighand->siglock); +} + +/** + * tty_audit_tiocsti - Log TIOCSTI + */ +void tty_audit_tiocsti(struct tty_struct *tty, char ch) +{ + struct tty_audit_buf *buf; + int major, minor, should_audit; + + spin_lock_irq(¤t->sighand->siglock); + should_audit = current->signal->audit_tty; + buf = current->signal->tty_audit_buf; + if (buf) + atomic_inc(&buf->count); + spin_unlock_irq(¤t->sighand->siglock); + + major = tty->driver->major; + minor = tty->driver->minor_start + tty->index; + if (buf) { + mutex_lock(&buf->mutex); + if (buf->major == major && buf->minor == minor) + tty_audit_buf_push_current(buf); + mutex_unlock(&buf->mutex); + tty_audit_buf_put(buf); + } + + if (should_audit && audit_enabled) { + uid_t auid; + unsigned int sessionid; + + auid = audit_get_loginuid(current); + sessionid = audit_get_sessionid(current); + tty_audit_log("ioctl=TIOCSTI", current, auid, sessionid, major, + minor, &ch, 1); + } +} + +/** + * tty_audit_push_task - Flush task's pending audit data + * @tsk: task pointer + * @loginuid: sender login uid + * @sessionid: sender session id + * + * Called with a ref on @tsk held. Try to lock sighand and get a + * reference to the tty audit buffer if available. + * Flush the buffer or return an appropriate error code. + */ +int tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid) +{ + struct tty_audit_buf *buf = ERR_PTR(-EPERM); + unsigned long flags; + + if (!lock_task_sighand(tsk, &flags)) + return -ESRCH; + + if (tsk->signal->audit_tty) { + buf = tsk->signal->tty_audit_buf; + if (buf) + atomic_inc(&buf->count); + } + unlock_task_sighand(tsk, &flags); + + /* + * Return 0 when signal->audit_tty set + * but tsk->signal->tty_audit_buf == NULL. + */ + if (!buf || IS_ERR(buf)) + return PTR_ERR(buf); + + mutex_lock(&buf->mutex); + tty_audit_buf_push(tsk, loginuid, sessionid, buf); + mutex_unlock(&buf->mutex); + + tty_audit_buf_put(buf); + return 0; +} + +/** + * tty_audit_buf_get - Get an audit buffer. + * + * Get an audit buffer for @tty, allocate it if necessary. Return %NULL + * if TTY auditing is disabled or out of memory. Otherwise, return a new + * reference to the buffer. + */ +static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty) +{ + struct tty_audit_buf *buf, *buf2; + + buf = NULL; + buf2 = NULL; + spin_lock_irq(¤t->sighand->siglock); + if (likely(!current->signal->audit_tty)) + goto out; + buf = current->signal->tty_audit_buf; + if (buf) { + atomic_inc(&buf->count); + goto out; + } + spin_unlock_irq(¤t->sighand->siglock); + + buf2 = tty_audit_buf_alloc(tty->driver->major, + tty->driver->minor_start + tty->index, + tty->icanon); + if (buf2 == NULL) { + audit_log_lost("out of memory in TTY auditing"); + return NULL; + } + + spin_lock_irq(¤t->sighand->siglock); + if (!current->signal->audit_tty) + goto out; + buf = current->signal->tty_audit_buf; + if (!buf) { + current->signal->tty_audit_buf = buf2; + buf = buf2; + buf2 = NULL; + } + atomic_inc(&buf->count); + /* Fall through */ + out: + spin_unlock_irq(¤t->sighand->siglock); + if (buf2) + tty_audit_buf_free(buf2); + return buf; +} + +/** + * tty_audit_add_data - Add data for TTY auditing. + * + * Audit @data of @size from @tty, if necessary. + */ +void tty_audit_add_data(struct tty_struct *tty, unsigned char *data, + size_t size) +{ + struct tty_audit_buf *buf; + int major, minor; + + if (unlikely(size == 0)) + return; + + if (tty->driver->type == TTY_DRIVER_TYPE_PTY + && tty->driver->subtype == PTY_TYPE_MASTER) + return; + + buf = tty_audit_buf_get(tty); + if (!buf) + return; + + mutex_lock(&buf->mutex); + major = tty->driver->major; + minor = tty->driver->minor_start + tty->index; + if (buf->major != major || buf->minor != minor + || buf->icanon != tty->icanon) { + tty_audit_buf_push_current(buf); + buf->major = major; + buf->minor = minor; + buf->icanon = tty->icanon; + } + do { + size_t run; + + run = N_TTY_BUF_SIZE - buf->valid; + if (run > size) + run = size; + memcpy(buf->data + buf->valid, data, run); + buf->valid += run; + data += run; + size -= run; + if (buf->valid == N_TTY_BUF_SIZE) + tty_audit_buf_push_current(buf); + } while (size != 0); + mutex_unlock(&buf->mutex); + tty_audit_buf_put(buf); +} + +/** + * tty_audit_push - Push buffered data out + * + * Make sure no audit data is pending for @tty on the current process. + */ +void tty_audit_push(struct tty_struct *tty) +{ + struct tty_audit_buf *buf; + + spin_lock_irq(¤t->sighand->siglock); + if (likely(!current->signal->audit_tty)) { + spin_unlock_irq(¤t->sighand->siglock); + return; + } + buf = current->signal->tty_audit_buf; + if (buf) + atomic_inc(&buf->count); + spin_unlock_irq(¤t->sighand->siglock); + + if (buf) { + int major, minor; + + major = tty->driver->major; + minor = tty->driver->minor_start + tty->index; + mutex_lock(&buf->mutex); + if (buf->major == major && buf->minor == minor) + tty_audit_buf_push_current(buf); + mutex_unlock(&buf->mutex); + tty_audit_buf_put(buf); + } +} diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c new file mode 100644 index 00000000000..cc1e9850d65 --- /dev/null +++ b/drivers/tty/tty_buffer.c @@ -0,0 +1,524 @@ +/* + * Tty buffer allocation management + */ + +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/module.h> + +/** + * tty_buffer_free_all - free buffers used by a tty + * @tty: tty to free from + * + * Remove all the buffers pending on a tty whether queued with data + * or in the free ring. Must be called when the tty is no longer in use + * + * Locking: none + */ + +void tty_buffer_free_all(struct tty_struct *tty) +{ + struct tty_buffer *thead; + while ((thead = tty->buf.head) != NULL) { + tty->buf.head = thead->next; + kfree(thead); + } + while ((thead = tty->buf.free) != NULL) { + tty->buf.free = thead->next; + kfree(thead); + } + tty->buf.tail = NULL; + tty->buf.memory_used = 0; +} + +/** + * tty_buffer_alloc - allocate a tty buffer + * @tty: tty device + * @size: desired size (characters) + * + * Allocate a new tty buffer to hold the desired number of characters. + * Return NULL if out of memory or the allocation would exceed the + * per device queue + * + * Locking: Caller must hold tty->buf.lock + */ + +static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) +{ + struct tty_buffer *p; + + if (tty->buf.memory_used + size > 65536) + return NULL; + p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); + if (p == NULL) + return NULL; + p->used = 0; + p->size = size; + p->next = NULL; + p->commit = 0; + p->read = 0; + p->char_buf_ptr = (char *)(p->data); + p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; + tty->buf.memory_used += size; + return p; +} + +/** + * tty_buffer_free - free a tty buffer + * @tty: tty owning the buffer + * @b: the buffer to free + * + * Free a tty buffer, or add it to the free list according to our + * internal strategy + * + * Locking: Caller must hold tty->buf.lock + */ + +static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) +{ + /* Dumb strategy for now - should keep some stats */ + tty->buf.memory_used -= b->size; + WARN_ON(tty->buf.memory_used < 0); + + if (b->size >= 512) + kfree(b); + else { + b->next = tty->buf.free; + tty->buf.free = b; + } +} + +/** + * __tty_buffer_flush - flush full tty buffers + * @tty: tty to flush + * + * flush all the buffers containing receive data. Caller must + * hold the buffer lock and must have ensured no parallel flush to + * ldisc is running. + * + * Locking: Caller must hold tty->buf.lock + */ + +static void __tty_buffer_flush(struct tty_struct *tty) +{ + struct tty_buffer *thead; + + while ((thead = tty->buf.head) != NULL) { + tty->buf.head = thead->next; + tty_buffer_free(tty, thead); + } + tty->buf.tail = NULL; +} + +/** + * tty_buffer_flush - flush full tty buffers + * @tty: tty to flush + * + * flush all the buffers containing receive data. If the buffer is + * being processed by flush_to_ldisc then we defer the processing + * to that function + * + * Locking: none + */ + +void tty_buffer_flush(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty->buf.lock, flags); + + /* If the data is being pushed to the tty layer then we can't + process it here. Instead set a flag and the flush_to_ldisc + path will process the flush request before it exits */ + if (test_bit(TTY_FLUSHING, &tty->flags)) { + set_bit(TTY_FLUSHPENDING, &tty->flags); + spin_unlock_irqrestore(&tty->buf.lock, flags); + wait_event(tty->read_wait, + test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); + return; + } else + __tty_buffer_flush(tty); + spin_unlock_irqrestore(&tty->buf.lock, flags); +} + +/** + * tty_buffer_find - find a free tty buffer + * @tty: tty owning the buffer + * @size: characters wanted + * + * Locate an existing suitable tty buffer or if we are lacking one then + * allocate a new one. We round our buffers off in 256 character chunks + * to get better allocation behaviour. + * + * Locking: Caller must hold tty->buf.lock + */ + +static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) +{ + struct tty_buffer **tbh = &tty->buf.free; + while ((*tbh) != NULL) { + struct tty_buffer *t = *tbh; + if (t->size >= size) { + *tbh = t->next; + t->next = NULL; + t->used = 0; + t->commit = 0; + t->read = 0; + tty->buf.memory_used += t->size; + return t; + } + tbh = &((*tbh)->next); + } + /* Round the buffer size out */ + size = (size + 0xFF) & ~0xFF; + return tty_buffer_alloc(tty, size); + /* Should possibly check if this fails for the largest buffer we + have queued and recycle that ? */ +} + +/** + * tty_buffer_request_room - grow tty buffer if needed + * @tty: tty structure + * @size: size desired + * + * Make at least size bytes of linear space available for the tty + * buffer. If we fail return the size we managed to find. + * + * Locking: Takes tty->buf.lock + */ +int tty_buffer_request_room(struct tty_struct *tty, size_t size) +{ + struct tty_buffer *b, *n; + int left; + unsigned long flags; + + spin_lock_irqsave(&tty->buf.lock, flags); + + /* OPTIMISATION: We could keep a per tty "zero" sized buffer to + remove this conditional if its worth it. This would be invisible + to the callers */ + if ((b = tty->buf.tail) != NULL) + left = b->size - b->used; + else + left = 0; + + if (left < size) { + /* This is the slow path - looking for new buffers to use */ + if ((n = tty_buffer_find(tty, size)) != NULL) { + if (b != NULL) { + b->next = n; + b->commit = b->used; + } else + tty->buf.head = n; + tty->buf.tail = n; + } else + size = left; + } + + spin_unlock_irqrestore(&tty->buf.lock, flags); + return size; +} +EXPORT_SYMBOL_GPL(tty_buffer_request_room); + +/** + * tty_insert_flip_string_fixed_flag - Add characters to the tty buffer + * @tty: tty structure + * @chars: characters + * @flag: flag value for each character + * @size: size + * + * Queue a series of bytes to the tty buffering. All the characters + * passed are marked with the supplied flag. Returns the number added. + * + * Locking: Called functions may take tty->buf.lock + */ + +int tty_insert_flip_string_fixed_flag(struct tty_struct *tty, + const unsigned char *chars, char flag, size_t size) +{ + int copied = 0; + do { + int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); + int space = tty_buffer_request_room(tty, goal); + struct tty_buffer *tb = tty->buf.tail; + /* If there is no space then tb may be NULL */ + if (unlikely(space == 0)) + break; + memcpy(tb->char_buf_ptr + tb->used, chars, space); + memset(tb->flag_buf_ptr + tb->used, flag, space); + tb->used += space; + copied += space; + chars += space; + /* There is a small chance that we need to split the data over + several buffers. If this is the case we must loop */ + } while (unlikely(size > copied)); + return copied; +} +EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag); + +/** + * tty_insert_flip_string_flags - Add characters to the tty buffer + * @tty: tty structure + * @chars: characters + * @flags: flag bytes + * @size: size + * + * Queue a series of bytes to the tty buffering. For each character + * the flags array indicates the status of the character. Returns the + * number added. + * + * Locking: Called functions may take tty->buf.lock + */ + +int tty_insert_flip_string_flags(struct tty_struct *tty, + const unsigned char *chars, const char *flags, size_t size) +{ + int copied = 0; + do { + int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); + int space = tty_buffer_request_room(tty, goal); + struct tty_buffer *tb = tty->buf.tail; + /* If there is no space then tb may be NULL */ + if (unlikely(space == 0)) + break; + memcpy(tb->char_buf_ptr + tb->used, chars, space); + memcpy(tb->flag_buf_ptr + tb->used, flags, space); + tb->used += space; + copied += space; + chars += space; + flags += space; + /* There is a small chance that we need to split the data over + several buffers. If this is the case we must loop */ + } while (unlikely(size > copied)); + return copied; +} +EXPORT_SYMBOL(tty_insert_flip_string_flags); + +/** + * tty_schedule_flip - push characters to ldisc + * @tty: tty to push from + * + * Takes any pending buffers and transfers their ownership to the + * ldisc side of the queue. It then schedules those characters for + * processing by the line discipline. + * + * Locking: Takes tty->buf.lock + */ + +void tty_schedule_flip(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty->buf.lock, flags); + if (tty->buf.tail != NULL) + tty->buf.tail->commit = tty->buf.tail->used; + spin_unlock_irqrestore(&tty->buf.lock, flags); + schedule_delayed_work(&tty->buf.work, 1); +} +EXPORT_SYMBOL(tty_schedule_flip); + +/** + * tty_prepare_flip_string - make room for characters + * @tty: tty + * @chars: return pointer for character write area + * @size: desired size + * + * Prepare a block of space in the buffer for data. Returns the length + * available and buffer pointer to the space which is now allocated and + * accounted for as ready for normal characters. This is used for drivers + * that need their own block copy routines into the buffer. There is no + * guarantee the buffer is a DMA target! + * + * Locking: May call functions taking tty->buf.lock + */ + +int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, + size_t size) +{ + int space = tty_buffer_request_room(tty, size); + if (likely(space)) { + struct tty_buffer *tb = tty->buf.tail; + *chars = tb->char_buf_ptr + tb->used; + memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); + tb->used += space; + } + return space; +} +EXPORT_SYMBOL_GPL(tty_prepare_flip_string); + +/** + * tty_prepare_flip_string_flags - make room for characters + * @tty: tty + * @chars: return pointer for character write area + * @flags: return pointer for status flag write area + * @size: desired size + * + * Prepare a block of space in the buffer for data. Returns the length + * available and buffer pointer to the space which is now allocated and + * accounted for as ready for characters. This is used for drivers + * that need their own block copy routines into the buffer. There is no + * guarantee the buffer is a DMA target! + * + * Locking: May call functions taking tty->buf.lock + */ + +int tty_prepare_flip_string_flags(struct tty_struct *tty, + unsigned char **chars, char **flags, size_t size) +{ + int space = tty_buffer_request_room(tty, size); + if (likely(space)) { + struct tty_buffer *tb = tty->buf.tail; + *chars = tb->char_buf_ptr + tb->used; + *flags = tb->flag_buf_ptr + tb->used; + tb->used += space; + } + return space; +} +EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); + + + +/** + * flush_to_ldisc + * @work: tty structure passed from work queue. + * + * This routine is called out of the software interrupt to flush data + * from the buffer chain to the line discipline. + * + * Locking: holds tty->buf.lock to guard buffer list. Drops the lock + * while invoking the line discipline receive_buf method. The + * receive_buf method is single threaded for each tty instance. + */ + +static void flush_to_ldisc(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, buf.work.work); + unsigned long flags; + struct tty_ldisc *disc; + + disc = tty_ldisc_ref(tty); + if (disc == NULL) /* !TTY_LDISC */ + return; + + spin_lock_irqsave(&tty->buf.lock, flags); + + if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) { + struct tty_buffer *head; + while ((head = tty->buf.head) != NULL) { + int count; + char *char_buf; + unsigned char *flag_buf; + + count = head->commit - head->read; + if (!count) { + if (head->next == NULL) + break; + tty->buf.head = head->next; + tty_buffer_free(tty, head); + continue; + } + /* Ldisc or user is trying to flush the buffers + we are feeding to the ldisc, stop feeding the + line discipline as we want to empty the queue */ + if (test_bit(TTY_FLUSHPENDING, &tty->flags)) + break; + if (!tty->receive_room) { + schedule_delayed_work(&tty->buf.work, 1); + break; + } + if (count > tty->receive_room) + count = tty->receive_room; + char_buf = head->char_buf_ptr + head->read; + flag_buf = head->flag_buf_ptr + head->read; + head->read += count; + spin_unlock_irqrestore(&tty->buf.lock, flags); + disc->ops->receive_buf(tty, char_buf, + flag_buf, count); + spin_lock_irqsave(&tty->buf.lock, flags); + } + clear_bit(TTY_FLUSHING, &tty->flags); + } + + /* We may have a deferred request to flush the input buffer, + if so pull the chain under the lock and empty the queue */ + if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { + __tty_buffer_flush(tty); + clear_bit(TTY_FLUSHPENDING, &tty->flags); + wake_up(&tty->read_wait); + } + spin_unlock_irqrestore(&tty->buf.lock, flags); + + tty_ldisc_deref(disc); +} + +/** + * tty_flush_to_ldisc + * @tty: tty to push + * + * Push the terminal flip buffers to the line discipline. + * + * Must not be called from IRQ context. + */ +void tty_flush_to_ldisc(struct tty_struct *tty) +{ + flush_delayed_work(&tty->buf.work); +} + +/** + * tty_flip_buffer_push - terminal + * @tty: tty to push + * + * Queue a push of the terminal flip buffers to the line discipline. This + * function must not be called from IRQ context if tty->low_latency is set. + * + * In the event of the queue being busy for flipping the work will be + * held off and retried later. + * + * Locking: tty buffer lock. Driver locks in low latency mode. + */ + +void tty_flip_buffer_push(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty->buf.lock, flags); + if (tty->buf.tail != NULL) + tty->buf.tail->commit = tty->buf.tail->used; + spin_unlock_irqrestore(&tty->buf.lock, flags); + + if (tty->low_latency) + flush_to_ldisc(&tty->buf.work.work); + else + schedule_delayed_work(&tty->buf.work, 1); +} +EXPORT_SYMBOL(tty_flip_buffer_push); + +/** + * tty_buffer_init - prepare a tty buffer structure + * @tty: tty to initialise + * + * Set up the initial state of the buffer management for a tty device. + * Must be called before the other tty buffer functions are used. + * + * Locking: none + */ + +void tty_buffer_init(struct tty_struct *tty) +{ + spin_lock_init(&tty->buf.lock); + tty->buf.head = NULL; + tty->buf.tail = NULL; + tty->buf.free = NULL; + tty->buf.memory_used = 0; + INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); +} + diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c new file mode 100644 index 00000000000..c05c5af5aa0 --- /dev/null +++ b/drivers/tty/tty_io.c @@ -0,0 +1,3263 @@ +/* + * linux/drivers/char/tty_io.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles + * or rs-channels. It also implements echoing, cooked mode etc. + * + * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. + * + * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the + * tty_struct and tty_queue structures. Previously there was an array + * of 256 tty_struct's which was statically allocated, and the + * tty_queue structures were allocated at boot time. Both are now + * dynamically allocated only when the tty is open. + * + * Also restructured routines so that there is more of a separation + * between the high-level tty routines (tty_io.c and tty_ioctl.c) and + * the low-level tty routines (serial.c, pty.c, console.c). This + * makes for cleaner and more compact code. -TYT, 9/17/92 + * + * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines + * which can be dynamically activated and de-activated by the line + * discipline handling modules (like SLIP). + * + * NOTE: pay no attention to the line discipline code (yet); its + * interface is still subject to change in this version... + * -- TYT, 1/31/92 + * + * Added functionality to the OPOST tty handling. No delays, but all + * other bits should be there. + * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. + * + * Rewrote canonical mode and added more termios flags. + * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 + * + * Reorganized FASYNC support so mouse code can share it. + * -- ctm@ardi.com, 9Sep95 + * + * New TIOCLINUX variants added. + * -- mj@k332.feld.cvut.cz, 19-Nov-95 + * + * Restrict vt switching via ioctl() + * -- grif@cs.ucr.edu, 5-Dec-95 + * + * Move console and virtual terminal code to more appropriate files, + * implement CONFIG_VT and generalize console device interface. + * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 + * + * Rewrote tty_init_dev and tty_release_dev to eliminate races. + * -- Bill Hawes <whawes@star.net>, June 97 + * + * Added devfs support. + * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 + * + * Added support for a Unix98-style ptmx device. + * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 + * + * Reduced memory usage for older ARM systems + * -- Russell King <rmk@arm.linux.org.uk> + * + * Move do_SAK() into process context. Less stack use in devfs functions. + * alloc_tty_struct() always uses kmalloc() + * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 + */ + +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/devpts_fs.h> +#include <linux/file.h> +#include <linux/fdtable.h> +#include <linux/console.h> +#include <linux/timer.h> +#include <linux/ctype.h> +#include <linux/kd.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/smp_lock.h> +#include <linux/device.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/seq_file.h> +#include <linux/serial.h> + +#include <linux/uaccess.h> +#include <asm/system.h> + +#include <linux/kbd_kern.h> +#include <linux/vt_kern.h> +#include <linux/selection.h> + +#include <linux/kmod.h> +#include <linux/nsproxy.h> + +#undef TTY_DEBUG_HANGUP + +#define TTY_PARANOIA_CHECK 1 +#define CHECK_TTY_COUNT 1 + +struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ + .c_iflag = ICRNL | IXON, + .c_oflag = OPOST | ONLCR, + .c_cflag = B38400 | CS8 | CREAD | HUPCL, + .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | + ECHOCTL | ECHOKE | IEXTEN, + .c_cc = INIT_C_CC, + .c_ispeed = 38400, + .c_ospeed = 38400 +}; + +EXPORT_SYMBOL(tty_std_termios); + +/* This list gets poked at by procfs and various bits of boot up code. This + could do with some rationalisation such as pulling the tty proc function + into this file */ + +LIST_HEAD(tty_drivers); /* linked list of tty drivers */ + +/* Mutex to protect creating and releasing a tty. This is shared with + vt.c for deeply disgusting hack reasons */ +DEFINE_MUTEX(tty_mutex); +EXPORT_SYMBOL(tty_mutex); + +/* Spinlock to protect the tty->tty_files list */ +DEFINE_SPINLOCK(tty_files_lock); + +static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); +static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); +ssize_t redirected_tty_write(struct file *, const char __user *, + size_t, loff_t *); +static unsigned int tty_poll(struct file *, poll_table *); +static int tty_open(struct inode *, struct file *); +long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +#ifdef CONFIG_COMPAT +static long tty_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg); +#else +#define tty_compat_ioctl NULL +#endif +static int __tty_fasync(int fd, struct file *filp, int on); +static int tty_fasync(int fd, struct file *filp, int on); +static void release_tty(struct tty_struct *tty, int idx); +static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); +static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); + +/** + * alloc_tty_struct - allocate a tty object + * + * Return a new empty tty structure. The data fields have not + * been initialized in any way but has been zeroed + * + * Locking: none + */ + +struct tty_struct *alloc_tty_struct(void) +{ + return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); +} + +/** + * free_tty_struct - free a disused tty + * @tty: tty struct to free + * + * Free the write buffers, tty queue and tty memory itself. + * + * Locking: none. Must be called after tty is definitely unused + */ + +void free_tty_struct(struct tty_struct *tty) +{ + if (tty->dev) + put_device(tty->dev); + kfree(tty->write_buf); + tty_buffer_free_all(tty); + kfree(tty); +} + +static inline struct tty_struct *file_tty(struct file *file) +{ + return ((struct tty_file_private *)file->private_data)->tty; +} + +/* Associate a new file with the tty structure */ +int tty_add_file(struct tty_struct *tty, struct file *file) +{ + struct tty_file_private *priv; + + priv = kmalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->tty = tty; + priv->file = file; + file->private_data = priv; + + spin_lock(&tty_files_lock); + list_add(&priv->list, &tty->tty_files); + spin_unlock(&tty_files_lock); + + return 0; +} + +/* Delete file from its tty */ +void tty_del_file(struct file *file) +{ + struct tty_file_private *priv = file->private_data; + + spin_lock(&tty_files_lock); + list_del(&priv->list); + spin_unlock(&tty_files_lock); + file->private_data = NULL; + kfree(priv); +} + + +#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) + +/** + * tty_name - return tty naming + * @tty: tty structure + * @buf: buffer for output + * + * Convert a tty structure into a name. The name reflects the kernel + * naming policy and if udev is in use may not reflect user space + * + * Locking: none + */ + +char *tty_name(struct tty_struct *tty, char *buf) +{ + if (!tty) /* Hmm. NULL pointer. That's fun. */ + strcpy(buf, "NULL tty"); + else + strcpy(buf, tty->name); + return buf; +} + +EXPORT_SYMBOL(tty_name); + +int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, + const char *routine) +{ +#ifdef TTY_PARANOIA_CHECK + if (!tty) { + printk(KERN_WARNING + "null TTY for (%d:%d) in %s\n", + imajor(inode), iminor(inode), routine); + return 1; + } + if (tty->magic != TTY_MAGIC) { + printk(KERN_WARNING + "bad magic number for tty struct (%d:%d) in %s\n", + imajor(inode), iminor(inode), routine); + return 1; + } +#endif + return 0; +} + +static int check_tty_count(struct tty_struct *tty, const char *routine) +{ +#ifdef CHECK_TTY_COUNT + struct list_head *p; + int count = 0; + + spin_lock(&tty_files_lock); + list_for_each(p, &tty->tty_files) { + count++; + } + spin_unlock(&tty_files_lock); + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_SLAVE && + tty->link && tty->link->count) + count++; + if (tty->count != count) { + printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " + "!= #fd's(%d) in %s\n", + tty->name, tty->count, count, routine); + return count; + } +#endif + return 0; +} + +/** + * get_tty_driver - find device of a tty + * @dev_t: device identifier + * @index: returns the index of the tty + * + * This routine returns a tty driver structure, given a device number + * and also passes back the index number. + * + * Locking: caller must hold tty_mutex + */ + +static struct tty_driver *get_tty_driver(dev_t device, int *index) +{ + struct tty_driver *p; + + list_for_each_entry(p, &tty_drivers, tty_drivers) { + dev_t base = MKDEV(p->major, p->minor_start); + if (device < base || device >= base + p->num) + continue; + *index = device - base; + return tty_driver_kref_get(p); + } + return NULL; +} + +#ifdef CONFIG_CONSOLE_POLL + +/** + * tty_find_polling_driver - find device of a polled tty + * @name: name string to match + * @line: pointer to resulting tty line nr + * + * This routine returns a tty driver structure, given a name + * and the condition that the tty driver is capable of polled + * operation. + */ +struct tty_driver *tty_find_polling_driver(char *name, int *line) +{ + struct tty_driver *p, *res = NULL; + int tty_line = 0; + int len; + char *str, *stp; + + for (str = name; *str; str++) + if ((*str >= '0' && *str <= '9') || *str == ',') + break; + if (!*str) + return NULL; + + len = str - name; + tty_line = simple_strtoul(str, &str, 10); + + mutex_lock(&tty_mutex); + /* Search through the tty devices to look for a match */ + list_for_each_entry(p, &tty_drivers, tty_drivers) { + if (strncmp(name, p->name, len) != 0) + continue; + stp = str; + if (*stp == ',') + stp++; + if (*stp == '\0') + stp = NULL; + + if (tty_line >= 0 && tty_line < p->num && p->ops && + p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) { + res = tty_driver_kref_get(p); + *line = tty_line; + break; + } + } + mutex_unlock(&tty_mutex); + + return res; +} +EXPORT_SYMBOL_GPL(tty_find_polling_driver); +#endif + +/** + * tty_check_change - check for POSIX terminal changes + * @tty: tty to check + * + * If we try to write to, or set the state of, a terminal and we're + * not in the foreground, send a SIGTTOU. If the signal is blocked or + * ignored, go ahead and perform the operation. (POSIX 7.2) + * + * Locking: ctrl_lock + */ + +int tty_check_change(struct tty_struct *tty) +{ + unsigned long flags; + int ret = 0; + + if (current->signal->tty != tty) + return 0; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + + if (!tty->pgrp) { + printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); + goto out_unlock; + } + if (task_pgrp(current) == tty->pgrp) + goto out_unlock; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (is_ignored(SIGTTOU)) + goto out; + if (is_current_pgrp_orphaned()) { + ret = -EIO; + goto out; + } + kill_pgrp(task_pgrp(current), SIGTTOU, 1); + set_thread_flag(TIF_SIGPENDING); + ret = -ERESTARTSYS; +out: + return ret; +out_unlock: + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + return ret; +} + +EXPORT_SYMBOL(tty_check_change); + +static ssize_t hung_up_tty_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + return 0; +} + +static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + return -EIO; +} + +/* No kernel lock held - none needed ;) */ +static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) +{ + return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; +} + +static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return cmd == TIOCSPGRP ? -ENOTTY : -EIO; +} + +static long hung_up_tty_compat_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + return cmd == TIOCSPGRP ? -ENOTTY : -EIO; +} + +static const struct file_operations tty_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = tty_write, + .poll = tty_poll, + .unlocked_ioctl = tty_ioctl, + .compat_ioctl = tty_compat_ioctl, + .open = tty_open, + .release = tty_release, + .fasync = tty_fasync, +}; + +static const struct file_operations console_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = redirected_tty_write, + .poll = tty_poll, + .unlocked_ioctl = tty_ioctl, + .compat_ioctl = tty_compat_ioctl, + .open = tty_open, + .release = tty_release, + .fasync = tty_fasync, +}; + +static const struct file_operations hung_up_tty_fops = { + .llseek = no_llseek, + .read = hung_up_tty_read, + .write = hung_up_tty_write, + .poll = hung_up_tty_poll, + .unlocked_ioctl = hung_up_tty_ioctl, + .compat_ioctl = hung_up_tty_compat_ioctl, + .release = tty_release, +}; + +static DEFINE_SPINLOCK(redirect_lock); +static struct file *redirect; + +/** + * tty_wakeup - request more data + * @tty: terminal + * + * Internal and external helper for wakeups of tty. This function + * informs the line discipline if present that the driver is ready + * to receive more output data. + */ + +void tty_wakeup(struct tty_struct *tty) +{ + struct tty_ldisc *ld; + + if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { + ld = tty_ldisc_ref(tty); + if (ld) { + if (ld->ops->write_wakeup) + ld->ops->write_wakeup(tty); + tty_ldisc_deref(ld); + } + } + wake_up_interruptible_poll(&tty->write_wait, POLLOUT); +} + +EXPORT_SYMBOL_GPL(tty_wakeup); + +/** + * __tty_hangup - actual handler for hangup events + * @work: tty device + * + * This can be called by the "eventd" kernel thread. That is process + * synchronous but doesn't hold any locks, so we need to make sure we + * have the appropriate locks for what we're doing. + * + * The hangup event clears any pending redirections onto the hung up + * device. It ensures future writes will error and it does the needed + * line discipline hangup and signal delivery. The tty object itself + * remains intact. + * + * Locking: + * BTM + * redirect lock for undoing redirection + * file list lock for manipulating list of ttys + * tty_ldisc_lock from called functions + * termios_mutex resetting termios data + * tasklist_lock to walk task list for hangup event + * ->siglock to protect ->signal/->sighand + */ +void __tty_hangup(struct tty_struct *tty) +{ + struct file *cons_filp = NULL; + struct file *filp, *f = NULL; + struct task_struct *p; + struct tty_file_private *priv; + int closecount = 0, n; + unsigned long flags; + int refs = 0; + + if (!tty) + return; + + + spin_lock(&redirect_lock); + if (redirect && file_tty(redirect) == tty) { + f = redirect; + redirect = NULL; + } + spin_unlock(&redirect_lock); + + tty_lock(); + + /* inuse_filps is protected by the single tty lock, + this really needs to change if we want to flush the + workqueue with the lock held */ + check_tty_count(tty, "tty_hangup"); + + spin_lock(&tty_files_lock); + /* This breaks for file handles being sent over AF_UNIX sockets ? */ + list_for_each_entry(priv, &tty->tty_files, list) { + filp = priv->file; + if (filp->f_op->write == redirected_tty_write) + cons_filp = filp; + if (filp->f_op->write != tty_write) + continue; + closecount++; + __tty_fasync(-1, filp, 0); /* can't block */ + filp->f_op = &hung_up_tty_fops; + } + spin_unlock(&tty_files_lock); + + tty_ldisc_hangup(tty); + + read_lock(&tasklist_lock); + if (tty->session) { + do_each_pid_task(tty->session, PIDTYPE_SID, p) { + spin_lock_irq(&p->sighand->siglock); + if (p->signal->tty == tty) { + p->signal->tty = NULL; + /* We defer the dereferences outside fo + the tasklist lock */ + refs++; + } + if (!p->signal->leader) { + spin_unlock_irq(&p->sighand->siglock); + continue; + } + __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); + __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); + put_pid(p->signal->tty_old_pgrp); /* A noop */ + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->pgrp) + p->signal->tty_old_pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + spin_unlock_irq(&p->sighand->siglock); + } while_each_pid_task(tty->session, PIDTYPE_SID, p); + } + read_unlock(&tasklist_lock); + + spin_lock_irqsave(&tty->ctrl_lock, flags); + clear_bit(TTY_THROTTLED, &tty->flags); + clear_bit(TTY_PUSH, &tty->flags); + clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + put_pid(tty->session); + put_pid(tty->pgrp); + tty->session = NULL; + tty->pgrp = NULL; + tty->ctrl_status = 0; + set_bit(TTY_HUPPED, &tty->flags); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + /* Account for the p->signal references we killed */ + while (refs--) + tty_kref_put(tty); + + /* + * If one of the devices matches a console pointer, we + * cannot just call hangup() because that will cause + * tty->count and state->count to go out of sync. + * So we just call close() the right number of times. + */ + if (cons_filp) { + if (tty->ops->close) + for (n = 0; n < closecount; n++) + tty->ops->close(tty, cons_filp); + } else if (tty->ops->hangup) + (tty->ops->hangup)(tty); + /* + * We don't want to have driver/ldisc interactions beyond + * the ones we did here. The driver layer expects no + * calls after ->hangup() from the ldisc side. However we + * can't yet guarantee all that. + */ + set_bit(TTY_HUPPED, &tty->flags); + tty_ldisc_enable(tty); + + tty_unlock(); + + if (f) + fput(f); +} + +static void do_tty_hangup(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, hangup_work); + + __tty_hangup(tty); +} + +/** + * tty_hangup - trigger a hangup event + * @tty: tty to hangup + * + * A carrier loss (virtual or otherwise) has occurred on this like + * schedule a hangup sequence to run after this event. + */ + +void tty_hangup(struct tty_struct *tty) +{ +#ifdef TTY_DEBUG_HANGUP + char buf[64]; + printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); +#endif + schedule_work(&tty->hangup_work); +} + +EXPORT_SYMBOL(tty_hangup); + +/** + * tty_vhangup - process vhangup + * @tty: tty to hangup + * + * The user has asked via system call for the terminal to be hung up. + * We do this synchronously so that when the syscall returns the process + * is complete. That guarantee is necessary for security reasons. + */ + +void tty_vhangup(struct tty_struct *tty) +{ +#ifdef TTY_DEBUG_HANGUP + char buf[64]; + + printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); +#endif + __tty_hangup(tty); +} + +EXPORT_SYMBOL(tty_vhangup); + + +/** + * tty_vhangup_self - process vhangup for own ctty + * + * Perform a vhangup on the current controlling tty + */ + +void tty_vhangup_self(void) +{ + struct tty_struct *tty; + + tty = get_current_tty(); + if (tty) { + tty_vhangup(tty); + tty_kref_put(tty); + } +} + +/** + * tty_hung_up_p - was tty hung up + * @filp: file pointer of tty + * + * Return true if the tty has been subject to a vhangup or a carrier + * loss + */ + +int tty_hung_up_p(struct file *filp) +{ + return (filp->f_op == &hung_up_tty_fops); +} + +EXPORT_SYMBOL(tty_hung_up_p); + +static void session_clear_tty(struct pid *session) +{ + struct task_struct *p; + do_each_pid_task(session, PIDTYPE_SID, p) { + proc_clear_tty(p); + } while_each_pid_task(session, PIDTYPE_SID, p); +} + +/** + * disassociate_ctty - disconnect controlling tty + * @on_exit: true if exiting so need to "hang up" the session + * + * This function is typically called only by the session leader, when + * it wants to disassociate itself from its controlling tty. + * + * It performs the following functions: + * (1) Sends a SIGHUP and SIGCONT to the foreground process group + * (2) Clears the tty from being controlling the session + * (3) Clears the controlling tty for all processes in the + * session group. + * + * The argument on_exit is set to 1 if called when a process is + * exiting; it is 0 if called by the ioctl TIOCNOTTY. + * + * Locking: + * BTM is taken for hysterical raisins, and held when + * called from no_tty(). + * tty_mutex is taken to protect tty + * ->siglock is taken to protect ->signal/->sighand + * tasklist_lock is taken to walk process list for sessions + * ->siglock is taken to protect ->signal/->sighand + */ + +void disassociate_ctty(int on_exit) +{ + struct tty_struct *tty; + struct pid *tty_pgrp = NULL; + + if (!current->signal->leader) + return; + + tty = get_current_tty(); + if (tty) { + tty_pgrp = get_pid(tty->pgrp); + if (on_exit) { + if (tty->driver->type != TTY_DRIVER_TYPE_PTY) + tty_vhangup(tty); + } + tty_kref_put(tty); + } else if (on_exit) { + struct pid *old_pgrp; + spin_lock_irq(¤t->sighand->siglock); + old_pgrp = current->signal->tty_old_pgrp; + current->signal->tty_old_pgrp = NULL; + spin_unlock_irq(¤t->sighand->siglock); + if (old_pgrp) { + kill_pgrp(old_pgrp, SIGHUP, on_exit); + kill_pgrp(old_pgrp, SIGCONT, on_exit); + put_pid(old_pgrp); + } + return; + } + if (tty_pgrp) { + kill_pgrp(tty_pgrp, SIGHUP, on_exit); + if (!on_exit) + kill_pgrp(tty_pgrp, SIGCONT, on_exit); + put_pid(tty_pgrp); + } + + spin_lock_irq(¤t->sighand->siglock); + put_pid(current->signal->tty_old_pgrp); + current->signal->tty_old_pgrp = NULL; + spin_unlock_irq(¤t->sighand->siglock); + + tty = get_current_tty(); + if (tty) { + unsigned long flags; + spin_lock_irqsave(&tty->ctrl_lock, flags); + put_pid(tty->session); + put_pid(tty->pgrp); + tty->session = NULL; + tty->pgrp = NULL; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + tty_kref_put(tty); + } else { +#ifdef TTY_DEBUG_HANGUP + printk(KERN_DEBUG "error attempted to write to tty [0x%p]" + " = NULL", tty); +#endif + } + + /* Now clear signal->tty under the lock */ + read_lock(&tasklist_lock); + session_clear_tty(task_session(current)); + read_unlock(&tasklist_lock); +} + +/** + * + * no_tty - Ensure the current process does not have a controlling tty + */ +void no_tty(void) +{ + struct task_struct *tsk = current; + tty_lock(); + disassociate_ctty(0); + tty_unlock(); + proc_clear_tty(tsk); +} + + +/** + * stop_tty - propagate flow control + * @tty: tty to stop + * + * Perform flow control to the driver. For PTY/TTY pairs we + * must also propagate the TIOCKPKT status. May be called + * on an already stopped device and will not re-call the driver + * method. + * + * This functionality is used by both the line disciplines for + * halting incoming flow and by the driver. It may therefore be + * called from any context, may be under the tty atomic_write_lock + * but not always. + * + * Locking: + * Uses the tty control lock internally + */ + +void stop_tty(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->stopped) { + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + return; + } + tty->stopped = 1; + if (tty->link && tty->link->packet) { + tty->ctrl_status &= ~TIOCPKT_START; + tty->ctrl_status |= TIOCPKT_STOP; + wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); + } + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (tty->ops->stop) + (tty->ops->stop)(tty); +} + +EXPORT_SYMBOL(stop_tty); + +/** + * start_tty - propagate flow control + * @tty: tty to start + * + * Start a tty that has been stopped if at all possible. Perform + * any necessary wakeups and propagate the TIOCPKT status. If this + * is the tty was previous stopped and is being started then the + * driver start method is invoked and the line discipline woken. + * + * Locking: + * ctrl_lock + */ + +void start_tty(struct tty_struct *tty) +{ + unsigned long flags; + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (!tty->stopped || tty->flow_stopped) { + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + return; + } + tty->stopped = 0; + if (tty->link && tty->link->packet) { + tty->ctrl_status &= ~TIOCPKT_STOP; + tty->ctrl_status |= TIOCPKT_START; + wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); + } + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + if (tty->ops->start) + (tty->ops->start)(tty); + /* If we have a running line discipline it may need kicking */ + tty_wakeup(tty); +} + +EXPORT_SYMBOL(start_tty); + +/** + * tty_read - read method for tty device files + * @file: pointer to tty file + * @buf: user buffer + * @count: size of user buffer + * @ppos: unused + * + * Perform the read system call function on this terminal device. Checks + * for hung up devices before calling the line discipline method. + * + * Locking: + * Locks the line discipline internally while needed. Multiple + * read calls may be outstanding in parallel. + */ + +static ssize_t tty_read(struct file *file, char __user *buf, size_t count, + loff_t *ppos) +{ + int i; + struct inode *inode = file->f_path.dentry->d_inode; + struct tty_struct *tty = file_tty(file); + struct tty_ldisc *ld; + + if (tty_paranoia_check(tty, inode, "tty_read")) + return -EIO; + if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) + return -EIO; + + /* We want to wait for the line discipline to sort out in this + situation */ + ld = tty_ldisc_ref_wait(tty); + if (ld->ops->read) + i = (ld->ops->read)(tty, file, buf, count); + else + i = -EIO; + tty_ldisc_deref(ld); + if (i > 0) + inode->i_atime = current_fs_time(inode->i_sb); + return i; +} + +void tty_write_unlock(struct tty_struct *tty) +{ + mutex_unlock(&tty->atomic_write_lock); + wake_up_interruptible_poll(&tty->write_wait, POLLOUT); +} + +int tty_write_lock(struct tty_struct *tty, int ndelay) +{ + if (!mutex_trylock(&tty->atomic_write_lock)) { + if (ndelay) + return -EAGAIN; + if (mutex_lock_interruptible(&tty->atomic_write_lock)) + return -ERESTARTSYS; + } + return 0; +} + +/* + * Split writes up in sane blocksizes to avoid + * denial-of-service type attacks + */ +static inline ssize_t do_tty_write( + ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), + struct tty_struct *tty, + struct file *file, + const char __user *buf, + size_t count) +{ + ssize_t ret, written = 0; + unsigned int chunk; + + ret = tty_write_lock(tty, file->f_flags & O_NDELAY); + if (ret < 0) + return ret; + + /* + * We chunk up writes into a temporary buffer. This + * simplifies low-level drivers immensely, since they + * don't have locking issues and user mode accesses. + * + * But if TTY_NO_WRITE_SPLIT is set, we should use a + * big chunk-size.. + * + * The default chunk-size is 2kB, because the NTTY + * layer has problems with bigger chunks. It will + * claim to be able to handle more characters than + * it actually does. + * + * FIXME: This can probably go away now except that 64K chunks + * are too likely to fail unless switched to vmalloc... + */ + chunk = 2048; + if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) + chunk = 65536; + if (count < chunk) + chunk = count; + + /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ + if (tty->write_cnt < chunk) { + unsigned char *buf_chunk; + + if (chunk < 1024) + chunk = 1024; + + buf_chunk = kmalloc(chunk, GFP_KERNEL); + if (!buf_chunk) { + ret = -ENOMEM; + goto out; + } + kfree(tty->write_buf); + tty->write_cnt = chunk; + tty->write_buf = buf_chunk; + } + + /* Do the write .. */ + for (;;) { + size_t size = count; + if (size > chunk) + size = chunk; + ret = -EFAULT; + if (copy_from_user(tty->write_buf, buf, size)) + break; + ret = write(tty, file, tty->write_buf, size); + if (ret <= 0) + break; + written += ret; + buf += ret; + count -= ret; + if (!count) + break; + ret = -ERESTARTSYS; + if (signal_pending(current)) + break; + cond_resched(); + } + if (written) { + struct inode *inode = file->f_path.dentry->d_inode; + inode->i_mtime = current_fs_time(inode->i_sb); + ret = written; + } +out: + tty_write_unlock(tty); + return ret; +} + +/** + * tty_write_message - write a message to a certain tty, not just the console. + * @tty: the destination tty_struct + * @msg: the message to write + * + * This is used for messages that need to be redirected to a specific tty. + * We don't put it into the syslog queue right now maybe in the future if + * really needed. + * + * We must still hold the BTM and test the CLOSING flag for the moment. + */ + +void tty_write_message(struct tty_struct *tty, char *msg) +{ + if (tty) { + mutex_lock(&tty->atomic_write_lock); + tty_lock(); + if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) { + tty_unlock(); + tty->ops->write(tty, msg, strlen(msg)); + } else + tty_unlock(); + tty_write_unlock(tty); + } + return; +} + + +/** + * tty_write - write method for tty device file + * @file: tty file pointer + * @buf: user data to write + * @count: bytes to write + * @ppos: unused + * + * Write data to a tty device via the line discipline. + * + * Locking: + * Locks the line discipline as required + * Writes to the tty driver are serialized by the atomic_write_lock + * and are then processed in chunks to the device. The line discipline + * write method will not be invoked in parallel for each device. + */ + +static ssize_t tty_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct tty_struct *tty = file_tty(file); + struct tty_ldisc *ld; + ssize_t ret; + + if (tty_paranoia_check(tty, inode, "tty_write")) + return -EIO; + if (!tty || !tty->ops->write || + (test_bit(TTY_IO_ERROR, &tty->flags))) + return -EIO; + /* Short term debug to catch buggy drivers */ + if (tty->ops->write_room == NULL) + printk(KERN_ERR "tty driver %s lacks a write_room method.\n", + tty->driver->name); + ld = tty_ldisc_ref_wait(tty); + if (!ld->ops->write) + ret = -EIO; + else + ret = do_tty_write(ld->ops->write, tty, file, buf, count); + tty_ldisc_deref(ld); + return ret; +} + +ssize_t redirected_tty_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct file *p = NULL; + + spin_lock(&redirect_lock); + if (redirect) { + get_file(redirect); + p = redirect; + } + spin_unlock(&redirect_lock); + + if (p) { + ssize_t res; + res = vfs_write(p, buf, count, &p->f_pos); + fput(p); + return res; + } + return tty_write(file, buf, count, ppos); +} + +static char ptychar[] = "pqrstuvwxyzabcde"; + +/** + * pty_line_name - generate name for a pty + * @driver: the tty driver in use + * @index: the minor number + * @p: output buffer of at least 6 bytes + * + * Generate a name from a driver reference and write it to the output + * buffer. + * + * Locking: None + */ +static void pty_line_name(struct tty_driver *driver, int index, char *p) +{ + int i = index + driver->name_base; + /* ->name is initialized to "ttyp", but "tty" is expected */ + sprintf(p, "%s%c%x", + driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, + ptychar[i >> 4 & 0xf], i & 0xf); +} + +/** + * tty_line_name - generate name for a tty + * @driver: the tty driver in use + * @index: the minor number + * @p: output buffer of at least 7 bytes + * + * Generate a name from a driver reference and write it to the output + * buffer. + * + * Locking: None + */ +static void tty_line_name(struct tty_driver *driver, int index, char *p) +{ + sprintf(p, "%s%d", driver->name, index + driver->name_base); +} + +/** + * tty_driver_lookup_tty() - find an existing tty, if any + * @driver: the driver for the tty + * @idx: the minor number + * + * Return the tty, if found or ERR_PTR() otherwise. + * + * Locking: tty_mutex must be held. If tty is found, the mutex must + * be held until the 'fast-open' is also done. Will change once we + * have refcounting in the driver and per driver locking + */ +static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, + struct inode *inode, int idx) +{ + struct tty_struct *tty; + + if (driver->ops->lookup) + return driver->ops->lookup(driver, inode, idx); + + tty = driver->ttys[idx]; + return tty; +} + +/** + * tty_init_termios - helper for termios setup + * @tty: the tty to set up + * + * Initialise the termios structures for this tty. Thus runs under + * the tty_mutex currently so we can be relaxed about ordering. + */ + +int tty_init_termios(struct tty_struct *tty) +{ + struct ktermios *tp; + int idx = tty->index; + + tp = tty->driver->termios[idx]; + if (tp == NULL) { + tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); + if (tp == NULL) + return -ENOMEM; + memcpy(tp, &tty->driver->init_termios, + sizeof(struct ktermios)); + tty->driver->termios[idx] = tp; + } + tty->termios = tp; + tty->termios_locked = tp + 1; + + /* Compatibility until drivers always set this */ + tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); + tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); + return 0; +} +EXPORT_SYMBOL_GPL(tty_init_termios); + +/** + * tty_driver_install_tty() - install a tty entry in the driver + * @driver: the driver for the tty + * @tty: the tty + * + * Install a tty object into the driver tables. The tty->index field + * will be set by the time this is called. This method is responsible + * for ensuring any need additional structures are allocated and + * configured. + * + * Locking: tty_mutex for now + */ +static int tty_driver_install_tty(struct tty_driver *driver, + struct tty_struct *tty) +{ + int idx = tty->index; + int ret; + + if (driver->ops->install) { + ret = driver->ops->install(driver, tty); + return ret; + } + + if (tty_init_termios(tty) == 0) { + tty_driver_kref_get(driver); + tty->count++; + driver->ttys[idx] = tty; + return 0; + } + return -ENOMEM; +} + +/** + * tty_driver_remove_tty() - remove a tty from the driver tables + * @driver: the driver for the tty + * @idx: the minor number + * + * Remvoe a tty object from the driver tables. The tty->index field + * will be set by the time this is called. + * + * Locking: tty_mutex for now + */ +static void tty_driver_remove_tty(struct tty_driver *driver, + struct tty_struct *tty) +{ + if (driver->ops->remove) + driver->ops->remove(driver, tty); + else + driver->ttys[tty->index] = NULL; +} + +/* + * tty_reopen() - fast re-open of an open tty + * @tty - the tty to open + * + * Return 0 on success, -errno on error. + * + * Locking: tty_mutex must be held from the time the tty was found + * till this open completes. + */ +static int tty_reopen(struct tty_struct *tty) +{ + struct tty_driver *driver = tty->driver; + + if (test_bit(TTY_CLOSING, &tty->flags)) + return -EIO; + + if (driver->type == TTY_DRIVER_TYPE_PTY && + driver->subtype == PTY_TYPE_MASTER) { + /* + * special case for PTY masters: only one open permitted, + * and the slave side open count is incremented as well. + */ + if (tty->count) + return -EIO; + + tty->link->count++; + } + tty->count++; + tty->driver = driver; /* N.B. why do this every time?? */ + + mutex_lock(&tty->ldisc_mutex); + WARN_ON(!test_bit(TTY_LDISC, &tty->flags)); + mutex_unlock(&tty->ldisc_mutex); + + return 0; +} + +/** + * tty_init_dev - initialise a tty device + * @driver: tty driver we are opening a device on + * @idx: device index + * @ret_tty: returned tty structure + * @first_ok: ok to open a new device (used by ptmx) + * + * Prepare a tty device. This may not be a "new" clean device but + * could also be an active device. The pty drivers require special + * handling because of this. + * + * Locking: + * The function is called under the tty_mutex, which + * protects us from the tty struct or driver itself going away. + * + * On exit the tty device has the line discipline attached and + * a reference count of 1. If a pair was created for pty/tty use + * and the other was a pty master then it too has a reference count of 1. + * + * WSH 06/09/97: Rewritten to remove races and properly clean up after a + * failed open. The new code protects the open with a mutex, so it's + * really quite straightforward. The mutex locking can probably be + * relaxed for the (most common) case of reopening a tty. + */ + +struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, + int first_ok) +{ + struct tty_struct *tty; + int retval; + + /* Check if pty master is being opened multiple times */ + if (driver->subtype == PTY_TYPE_MASTER && + (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) { + return ERR_PTR(-EIO); + } + + /* + * First time open is complex, especially for PTY devices. + * This code guarantees that either everything succeeds and the + * TTY is ready for operation, or else the table slots are vacated + * and the allocated memory released. (Except that the termios + * and locked termios may be retained.) + */ + + if (!try_module_get(driver->owner)) + return ERR_PTR(-ENODEV); + + tty = alloc_tty_struct(); + if (!tty) + goto fail_no_mem; + initialize_tty_struct(tty, driver, idx); + + retval = tty_driver_install_tty(driver, tty); + if (retval < 0) { + free_tty_struct(tty); + module_put(driver->owner); + return ERR_PTR(retval); + } + + /* + * Structures all installed ... call the ldisc open routines. + * If we fail here just call release_tty to clean up. No need + * to decrement the use counts, as release_tty doesn't care. + */ + retval = tty_ldisc_setup(tty, tty->link); + if (retval) + goto release_mem_out; + return tty; + +fail_no_mem: + module_put(driver->owner); + return ERR_PTR(-ENOMEM); + + /* call the tty release_tty routine to clean out this slot */ +release_mem_out: + if (printk_ratelimit()) + printk(KERN_INFO "tty_init_dev: ldisc open failed, " + "clearing slot %d\n", idx); + release_tty(tty, idx); + return ERR_PTR(retval); +} + +void tty_free_termios(struct tty_struct *tty) +{ + struct ktermios *tp; + int idx = tty->index; + /* Kill this flag and push into drivers for locking etc */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { + /* FIXME: Locking on ->termios array */ + tp = tty->termios; + tty->driver->termios[idx] = NULL; + kfree(tp); + } +} +EXPORT_SYMBOL(tty_free_termios); + +void tty_shutdown(struct tty_struct *tty) +{ + tty_driver_remove_tty(tty->driver, tty); + tty_free_termios(tty); +} +EXPORT_SYMBOL(tty_shutdown); + +/** + * release_one_tty - release tty structure memory + * @kref: kref of tty we are obliterating + * + * Releases memory associated with a tty structure, and clears out the + * driver table slots. This function is called when a device is no longer + * in use. It also gets called when setup of a device fails. + * + * Locking: + * tty_mutex - sometimes only + * takes the file list lock internally when working on the list + * of ttys that the driver keeps. + * + * This method gets called from a work queue so that the driver private + * cleanup ops can sleep (needed for USB at least) + */ +static void release_one_tty(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, hangup_work); + struct tty_driver *driver = tty->driver; + + if (tty->ops->cleanup) + tty->ops->cleanup(tty); + + tty->magic = 0; + tty_driver_kref_put(driver); + module_put(driver->owner); + + spin_lock(&tty_files_lock); + list_del_init(&tty->tty_files); + spin_unlock(&tty_files_lock); + + put_pid(tty->pgrp); + put_pid(tty->session); + free_tty_struct(tty); +} + +static void queue_release_one_tty(struct kref *kref) +{ + struct tty_struct *tty = container_of(kref, struct tty_struct, kref); + + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + else + tty_shutdown(tty); + + /* The hangup queue is now free so we can reuse it rather than + waste a chunk of memory for each port */ + INIT_WORK(&tty->hangup_work, release_one_tty); + schedule_work(&tty->hangup_work); +} + +/** + * tty_kref_put - release a tty kref + * @tty: tty device + * + * Release a reference to a tty device and if need be let the kref + * layer destruct the object for us + */ + +void tty_kref_put(struct tty_struct *tty) +{ + if (tty) + kref_put(&tty->kref, queue_release_one_tty); +} +EXPORT_SYMBOL(tty_kref_put); + +/** + * release_tty - release tty structure memory + * + * Release both @tty and a possible linked partner (think pty pair), + * and decrement the refcount of the backing module. + * + * Locking: + * tty_mutex - sometimes only + * takes the file list lock internally when working on the list + * of ttys that the driver keeps. + * FIXME: should we require tty_mutex is held here ?? + * + */ +static void release_tty(struct tty_struct *tty, int idx) +{ + /* This should always be true but check for the moment */ + WARN_ON(tty->index != idx); + + if (tty->link) + tty_kref_put(tty->link); + tty_kref_put(tty); +} + +/** + * tty_release - vfs callback for close + * @inode: inode of tty + * @filp: file pointer for handle to tty + * + * Called the last time each file handle is closed that references + * this tty. There may however be several such references. + * + * Locking: + * Takes bkl. See tty_release_dev + * + * Even releasing the tty structures is a tricky business.. We have + * to be very careful that the structures are all released at the + * same time, as interrupts might otherwise get the wrong pointers. + * + * WSH 09/09/97: rewritten to avoid some nasty race conditions that could + * lead to double frees or releasing memory still in use. + */ + +int tty_release(struct inode *inode, struct file *filp) +{ + struct tty_struct *tty = file_tty(filp); + struct tty_struct *o_tty; + int pty_master, tty_closing, o_tty_closing, do_sleep; + int devpts; + int idx; + char buf[64]; + + if (tty_paranoia_check(tty, inode, "tty_release_dev")) + return 0; + + tty_lock(); + check_tty_count(tty, "tty_release_dev"); + + __tty_fasync(-1, filp, 0); + + idx = tty->index; + pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER); + devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; + o_tty = tty->link; + +#ifdef TTY_PARANOIA_CHECK + if (idx < 0 || idx >= tty->driver->num) { + printk(KERN_DEBUG "tty_release_dev: bad idx when trying to " + "free (%s)\n", tty->name); + tty_unlock(); + return 0; + } + if (!devpts) { + if (tty != tty->driver->ttys[idx]) { + tty_unlock(); + printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty " + "for (%s)\n", idx, tty->name); + return 0; + } + if (tty->termios != tty->driver->termios[idx]) { + tty_unlock(); + printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios " + "for (%s)\n", + idx, tty->name); + return 0; + } + } +#endif + +#ifdef TTY_DEBUG_HANGUP + printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...", + tty_name(tty, buf), tty->count); +#endif + +#ifdef TTY_PARANOIA_CHECK + if (tty->driver->other && + !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { + if (o_tty != tty->driver->other->ttys[idx]) { + tty_unlock(); + printk(KERN_DEBUG "tty_release_dev: other->table[%d] " + "not o_tty for (%s)\n", + idx, tty->name); + return 0 ; + } + if (o_tty->termios != tty->driver->other->termios[idx]) { + tty_unlock(); + printk(KERN_DEBUG "tty_release_dev: other->termios[%d] " + "not o_termios for (%s)\n", + idx, tty->name); + return 0; + } + if (o_tty->link != tty) { + tty_unlock(); + printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n"); + return 0; + } + } +#endif + if (tty->ops->close) + tty->ops->close(tty, filp); + + tty_unlock(); + /* + * Sanity check: if tty->count is going to zero, there shouldn't be + * any waiters on tty->read_wait or tty->write_wait. We test the + * wait queues and kick everyone out _before_ actually starting to + * close. This ensures that we won't block while releasing the tty + * structure. + * + * The test for the o_tty closing is necessary, since the master and + * slave sides may close in any order. If the slave side closes out + * first, its count will be one, since the master side holds an open. + * Thus this test wouldn't be triggered at the time the slave closes, + * so we do it now. + * + * Note that it's possible for the tty to be opened again while we're + * flushing out waiters. By recalculating the closing flags before + * each iteration we avoid any problems. + */ + while (1) { + /* Guard against races with tty->count changes elsewhere and + opens on /dev/tty */ + + mutex_lock(&tty_mutex); + tty_lock(); + tty_closing = tty->count <= 1; + o_tty_closing = o_tty && + (o_tty->count <= (pty_master ? 1 : 0)); + do_sleep = 0; + + if (tty_closing) { + if (waitqueue_active(&tty->read_wait)) { + wake_up_poll(&tty->read_wait, POLLIN); + do_sleep++; + } + if (waitqueue_active(&tty->write_wait)) { + wake_up_poll(&tty->write_wait, POLLOUT); + do_sleep++; + } + } + if (o_tty_closing) { + if (waitqueue_active(&o_tty->read_wait)) { + wake_up_poll(&o_tty->read_wait, POLLIN); + do_sleep++; + } + if (waitqueue_active(&o_tty->write_wait)) { + wake_up_poll(&o_tty->write_wait, POLLOUT); + do_sleep++; + } + } + if (!do_sleep) + break; + + printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue " + "active!\n", tty_name(tty, buf)); + tty_unlock(); + mutex_unlock(&tty_mutex); + schedule(); + } + + /* + * The closing flags are now consistent with the open counts on + * both sides, and we've completed the last operation that could + * block, so it's safe to proceed with closing. + */ + if (pty_master) { + if (--o_tty->count < 0) { + printk(KERN_WARNING "tty_release_dev: bad pty slave count " + "(%d) for %s\n", + o_tty->count, tty_name(o_tty, buf)); + o_tty->count = 0; + } + } + if (--tty->count < 0) { + printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n", + tty->count, tty_name(tty, buf)); + tty->count = 0; + } + + /* + * We've decremented tty->count, so we need to remove this file + * descriptor off the tty->tty_files list; this serves two + * purposes: + * - check_tty_count sees the correct number of file descriptors + * associated with this tty. + * - do_tty_hangup no longer sees this file descriptor as + * something that needs to be handled for hangups. + */ + tty_del_file(filp); + + /* + * Perform some housekeeping before deciding whether to return. + * + * Set the TTY_CLOSING flag if this was the last open. In the + * case of a pty we may have to wait around for the other side + * to close, and TTY_CLOSING makes sure we can't be reopened. + */ + if (tty_closing) + set_bit(TTY_CLOSING, &tty->flags); + if (o_tty_closing) + set_bit(TTY_CLOSING, &o_tty->flags); + + /* + * If _either_ side is closing, make sure there aren't any + * processes that still think tty or o_tty is their controlling + * tty. + */ + if (tty_closing || o_tty_closing) { + read_lock(&tasklist_lock); + session_clear_tty(tty->session); + if (o_tty) + session_clear_tty(o_tty->session); + read_unlock(&tasklist_lock); + } + + mutex_unlock(&tty_mutex); + + /* check whether both sides are closing ... */ + if (!tty_closing || (o_tty && !o_tty_closing)) { + tty_unlock(); + return 0; + } + +#ifdef TTY_DEBUG_HANGUP + printk(KERN_DEBUG "freeing tty structure..."); +#endif + /* + * Ask the line discipline code to release its structures + */ + tty_ldisc_release(tty, o_tty); + /* + * The release_tty function takes care of the details of clearing + * the slots and preserving the termios structure. + */ + release_tty(tty, idx); + + /* Make this pty number available for reallocation */ + if (devpts) + devpts_kill_index(inode, idx); + tty_unlock(); + return 0; +} + +/** + * tty_open - open a tty device + * @inode: inode of device file + * @filp: file pointer to tty + * + * tty_open and tty_release keep up the tty count that contains the + * number of opens done on a tty. We cannot use the inode-count, as + * different inodes might point to the same tty. + * + * Open-counting is needed for pty masters, as well as for keeping + * track of serial lines: DTR is dropped when the last close happens. + * (This is not done solely through tty->count, now. - Ted 1/27/92) + * + * The termios state of a pty is reset on first open so that + * settings don't persist across reuse. + * + * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work. + * tty->count should protect the rest. + * ->siglock protects ->signal/->sighand + */ + +static int tty_open(struct inode *inode, struct file *filp) +{ + struct tty_struct *tty = NULL; + int noctty, retval; + struct tty_driver *driver; + int index; + dev_t device = inode->i_rdev; + unsigned saved_flags = filp->f_flags; + + nonseekable_open(inode, filp); + +retry_open: + noctty = filp->f_flags & O_NOCTTY; + index = -1; + retval = 0; + + mutex_lock(&tty_mutex); + tty_lock(); + + if (device == MKDEV(TTYAUX_MAJOR, 0)) { + tty = get_current_tty(); + if (!tty) { + tty_unlock(); + mutex_unlock(&tty_mutex); + return -ENXIO; + } + driver = tty_driver_kref_get(tty->driver); + index = tty->index; + filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ + /* noctty = 1; */ + /* FIXME: Should we take a driver reference ? */ + tty_kref_put(tty); + goto got_driver; + } +#ifdef CONFIG_VT + if (device == MKDEV(TTY_MAJOR, 0)) { + extern struct tty_driver *console_driver; + driver = tty_driver_kref_get(console_driver); + index = fg_console; + noctty = 1; + goto got_driver; + } +#endif + if (device == MKDEV(TTYAUX_MAJOR, 1)) { + struct tty_driver *console_driver = console_device(&index); + if (console_driver) { + driver = tty_driver_kref_get(console_driver); + if (driver) { + /* Don't let /dev/console block */ + filp->f_flags |= O_NONBLOCK; + noctty = 1; + goto got_driver; + } + } + tty_unlock(); + mutex_unlock(&tty_mutex); + return -ENODEV; + } + + driver = get_tty_driver(device, &index); + if (!driver) { + tty_unlock(); + mutex_unlock(&tty_mutex); + return -ENODEV; + } +got_driver: + if (!tty) { + /* check whether we're reopening an existing tty */ + tty = tty_driver_lookup_tty(driver, inode, index); + + if (IS_ERR(tty)) { + tty_unlock(); + mutex_unlock(&tty_mutex); + return PTR_ERR(tty); + } + } + + if (tty) { + retval = tty_reopen(tty); + if (retval) + tty = ERR_PTR(retval); + } else + tty = tty_init_dev(driver, index, 0); + + mutex_unlock(&tty_mutex); + tty_driver_kref_put(driver); + if (IS_ERR(tty)) { + tty_unlock(); + return PTR_ERR(tty); + } + + retval = tty_add_file(tty, filp); + if (retval) { + tty_unlock(); + return retval; + } + + check_tty_count(tty, "tty_open"); + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + noctty = 1; +#ifdef TTY_DEBUG_HANGUP + printk(KERN_DEBUG "opening %s...", tty->name); +#endif + if (!retval) { + if (tty->ops->open) + retval = tty->ops->open(tty, filp); + else + retval = -ENODEV; + } + filp->f_flags = saved_flags; + + if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && + !capable(CAP_SYS_ADMIN)) + retval = -EBUSY; + + if (retval) { +#ifdef TTY_DEBUG_HANGUP + printk(KERN_DEBUG "error %d in opening %s...", retval, + tty->name); +#endif + tty_unlock(); /* need to call tty_release without BTM */ + tty_release(inode, filp); + if (retval != -ERESTARTSYS) + return retval; + + if (signal_pending(current)) + return retval; + + schedule(); + /* + * Need to reset f_op in case a hangup happened. + */ + tty_lock(); + if (filp->f_op == &hung_up_tty_fops) + filp->f_op = &tty_fops; + tty_unlock(); + goto retry_open; + } + tty_unlock(); + + + mutex_lock(&tty_mutex); + tty_lock(); + spin_lock_irq(¤t->sighand->siglock); + if (!noctty && + current->signal->leader && + !current->signal->tty && + tty->session == NULL) + __proc_set_tty(current, tty); + spin_unlock_irq(¤t->sighand->siglock); + tty_unlock(); + mutex_unlock(&tty_mutex); + return 0; +} + + + +/** + * tty_poll - check tty status + * @filp: file being polled + * @wait: poll wait structures to update + * + * Call the line discipline polling method to obtain the poll + * status of the device. + * + * Locking: locks called line discipline but ldisc poll method + * may be re-entered freely by other callers. + */ + +static unsigned int tty_poll(struct file *filp, poll_table *wait) +{ + struct tty_struct *tty = file_tty(filp); + struct tty_ldisc *ld; + int ret = 0; + + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) + return 0; + + ld = tty_ldisc_ref_wait(tty); + if (ld->ops->poll) + ret = (ld->ops->poll)(tty, filp, wait); + tty_ldisc_deref(ld); + return ret; +} + +static int __tty_fasync(int fd, struct file *filp, int on) +{ + struct tty_struct *tty = file_tty(filp); + unsigned long flags; + int retval = 0; + + if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) + goto out; + + retval = fasync_helper(fd, filp, on, &tty->fasync); + if (retval <= 0) + goto out; + + if (on) { + enum pid_type type; + struct pid *pid; + if (!waitqueue_active(&tty->read_wait)) + tty->minimum_to_wake = 1; + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (tty->pgrp) { + pid = tty->pgrp; + type = PIDTYPE_PGID; + } else { + pid = task_pid(current); + type = PIDTYPE_PID; + } + get_pid(pid); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + retval = __f_setown(filp, pid, type, 0); + put_pid(pid); + if (retval) + goto out; + } else { + if (!tty->fasync && !waitqueue_active(&tty->read_wait)) + tty->minimum_to_wake = N_TTY_BUF_SIZE; + } + retval = 0; +out: + return retval; +} + +static int tty_fasync(int fd, struct file *filp, int on) +{ + int retval; + tty_lock(); + retval = __tty_fasync(fd, filp, on); + tty_unlock(); + return retval; +} + +/** + * tiocsti - fake input character + * @tty: tty to fake input into + * @p: pointer to character + * + * Fake input to a tty device. Does the necessary locking and + * input management. + * + * FIXME: does not honour flow control ?? + * + * Locking: + * Called functions take tty_ldisc_lock + * current->signal->tty check is safe without locks + * + * FIXME: may race normal receive processing + */ + +static int tiocsti(struct tty_struct *tty, char __user *p) +{ + char ch, mbz = 0; + struct tty_ldisc *ld; + + if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) + return -EPERM; + if (get_user(ch, p)) + return -EFAULT; + tty_audit_tiocsti(tty, ch); + ld = tty_ldisc_ref_wait(tty); + ld->ops->receive_buf(tty, &ch, &mbz, 1); + tty_ldisc_deref(ld); + return 0; +} + +/** + * tiocgwinsz - implement window query ioctl + * @tty; tty + * @arg: user buffer for result + * + * Copies the kernel idea of the window size into the user buffer. + * + * Locking: tty->termios_mutex is taken to ensure the winsize data + * is consistent. + */ + +static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) +{ + int err; + + mutex_lock(&tty->termios_mutex); + err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); + mutex_unlock(&tty->termios_mutex); + + return err ? -EFAULT: 0; +} + +/** + * tty_do_resize - resize event + * @tty: tty being resized + * @rows: rows (character) + * @cols: cols (character) + * + * Update the termios variables and send the necessary signals to + * peform a terminal resize correctly + */ + +int tty_do_resize(struct tty_struct *tty, struct winsize *ws) +{ + struct pid *pgrp; + unsigned long flags; + + /* Lock the tty */ + mutex_lock(&tty->termios_mutex); + if (!memcmp(ws, &tty->winsize, sizeof(*ws))) + goto done; + /* Get the PID values and reference them so we can + avoid holding the tty ctrl lock while sending signals */ + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + if (pgrp) + kill_pgrp(pgrp, SIGWINCH, 1); + put_pid(pgrp); + + tty->winsize = *ws; +done: + mutex_unlock(&tty->termios_mutex); + return 0; +} + +/** + * tiocswinsz - implement window size set ioctl + * @tty; tty side of tty + * @arg: user buffer for result + * + * Copies the user idea of the window size to the kernel. Traditionally + * this is just advisory information but for the Linux console it + * actually has driver level meaning and triggers a VC resize. + * + * Locking: + * Driver dependant. The default do_resize method takes the + * tty termios mutex and ctrl_lock. The console takes its own lock + * then calls into the default method. + */ + +static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg) +{ + struct winsize tmp_ws; + if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) + return -EFAULT; + + if (tty->ops->resize) + return tty->ops->resize(tty, &tmp_ws); + else + return tty_do_resize(tty, &tmp_ws); +} + +/** + * tioccons - allow admin to move logical console + * @file: the file to become console + * + * Allow the adminstrator to move the redirected console device + * + * Locking: uses redirect_lock to guard the redirect information + */ + +static int tioccons(struct file *file) +{ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (file->f_op->write == redirected_tty_write) { + struct file *f; + spin_lock(&redirect_lock); + f = redirect; + redirect = NULL; + spin_unlock(&redirect_lock); + if (f) + fput(f); + return 0; + } + spin_lock(&redirect_lock); + if (redirect) { + spin_unlock(&redirect_lock); + return -EBUSY; + } + get_file(file); + redirect = file; + spin_unlock(&redirect_lock); + return 0; +} + +/** + * fionbio - non blocking ioctl + * @file: file to set blocking value + * @p: user parameter + * + * Historical tty interfaces had a blocking control ioctl before + * the generic functionality existed. This piece of history is preserved + * in the expected tty API of posix OS's. + * + * Locking: none, the open file handle ensures it won't go away. + */ + +static int fionbio(struct file *file, int __user *p) +{ + int nonblock; + + if (get_user(nonblock, p)) + return -EFAULT; + + spin_lock(&file->f_lock); + if (nonblock) + file->f_flags |= O_NONBLOCK; + else + file->f_flags &= ~O_NONBLOCK; + spin_unlock(&file->f_lock); + return 0; +} + +/** + * tiocsctty - set controlling tty + * @tty: tty structure + * @arg: user argument + * + * This ioctl is used to manage job control. It permits a session + * leader to set this tty as the controlling tty for the session. + * + * Locking: + * Takes tty_mutex() to protect tty instance + * Takes tasklist_lock internally to walk sessions + * Takes ->siglock() when updating signal->tty + */ + +static int tiocsctty(struct tty_struct *tty, int arg) +{ + int ret = 0; + if (current->signal->leader && (task_session(current) == tty->session)) + return ret; + + mutex_lock(&tty_mutex); + /* + * The process must be a session leader and + * not have a controlling tty already. + */ + if (!current->signal->leader || current->signal->tty) { + ret = -EPERM; + goto unlock; + } + + if (tty->session) { + /* + * This tty is already the controlling + * tty for another session group! + */ + if (arg == 1 && capable(CAP_SYS_ADMIN)) { + /* + * Steal it away + */ + read_lock(&tasklist_lock); + session_clear_tty(tty->session); + read_unlock(&tasklist_lock); + } else { + ret = -EPERM; + goto unlock; + } + } + proc_set_tty(current, tty); +unlock: + mutex_unlock(&tty_mutex); + return ret; +} + +/** + * tty_get_pgrp - return a ref counted pgrp pid + * @tty: tty to read + * + * Returns a refcounted instance of the pid struct for the process + * group controlling the tty. + */ + +struct pid *tty_get_pgrp(struct tty_struct *tty) +{ + unsigned long flags; + struct pid *pgrp; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + return pgrp; +} +EXPORT_SYMBOL_GPL(tty_get_pgrp); + +/** + * tiocgpgrp - get process group + * @tty: tty passed by user + * @real_tty: tty side of the tty pased by the user if a pty else the tty + * @p: returned pid + * + * Obtain the process group of the tty. If there is no process group + * return an error. + * + * Locking: none. Reference to current->signal->tty is safe. + */ + +static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + struct pid *pid; + int ret; + /* + * (tty == real_tty) is a cheap way of + * testing if the tty is NOT a master pty. + */ + if (tty == real_tty && current->signal->tty != real_tty) + return -ENOTTY; + pid = tty_get_pgrp(real_tty); + ret = put_user(pid_vnr(pid), p); + put_pid(pid); + return ret; +} + +/** + * tiocspgrp - attempt to set process group + * @tty: tty passed by user + * @real_tty: tty side device matching tty passed by user + * @p: pid pointer + * + * Set the process group of the tty to the session passed. Only + * permitted where the tty session is our session. + * + * Locking: RCU, ctrl lock + */ + +static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + struct pid *pgrp; + pid_t pgrp_nr; + int retval = tty_check_change(real_tty); + unsigned long flags; + + if (retval == -EIO) + return -ENOTTY; + if (retval) + return retval; + if (!current->signal->tty || + (current->signal->tty != real_tty) || + (real_tty->session != task_session(current))) + return -ENOTTY; + if (get_user(pgrp_nr, p)) + return -EFAULT; + if (pgrp_nr < 0) + return -EINVAL; + rcu_read_lock(); + pgrp = find_vpid(pgrp_nr); + retval = -ESRCH; + if (!pgrp) + goto out_unlock; + retval = -EPERM; + if (session_of_pgrp(pgrp) != task_session(current)) + goto out_unlock; + retval = 0; + spin_lock_irqsave(&tty->ctrl_lock, flags); + put_pid(real_tty->pgrp); + real_tty->pgrp = get_pid(pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); +out_unlock: + rcu_read_unlock(); + return retval; +} + +/** + * tiocgsid - get session id + * @tty: tty passed by user + * @real_tty: tty side of the tty pased by the user if a pty else the tty + * @p: pointer to returned session id + * + * Obtain the session id of the tty. If there is no session + * return an error. + * + * Locking: none. Reference to current->signal->tty is safe. + */ + +static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) +{ + /* + * (tty == real_tty) is a cheap way of + * testing if the tty is NOT a master pty. + */ + if (tty == real_tty && current->signal->tty != real_tty) + return -ENOTTY; + if (!real_tty->session) + return -ENOTTY; + return put_user(pid_vnr(real_tty->session), p); +} + +/** + * tiocsetd - set line discipline + * @tty: tty device + * @p: pointer to user data + * + * Set the line discipline according to user request. + * + * Locking: see tty_set_ldisc, this function is just a helper + */ + +static int tiocsetd(struct tty_struct *tty, int __user *p) +{ + int ldisc; + int ret; + + if (get_user(ldisc, p)) + return -EFAULT; + + ret = tty_set_ldisc(tty, ldisc); + + return ret; +} + +/** + * send_break - performed time break + * @tty: device to break on + * @duration: timeout in mS + * + * Perform a timed break on hardware that lacks its own driver level + * timed break functionality. + * + * Locking: + * atomic_write_lock serializes + * + */ + +static int send_break(struct tty_struct *tty, unsigned int duration) +{ + int retval; + + if (tty->ops->break_ctl == NULL) + return 0; + + if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK) + retval = tty->ops->break_ctl(tty, duration); + else { + /* Do the work ourselves */ + if (tty_write_lock(tty, 0) < 0) + return -EINTR; + retval = tty->ops->break_ctl(tty, -1); + if (retval) + goto out; + if (!signal_pending(current)) + msleep_interruptible(duration); + retval = tty->ops->break_ctl(tty, 0); +out: + tty_write_unlock(tty); + if (signal_pending(current)) + retval = -EINTR; + } + return retval; +} + +/** + * tty_tiocmget - get modem status + * @tty: tty device + * @file: user file pointer + * @p: pointer to result + * + * Obtain the modem status bits from the tty driver if the feature + * is supported. Return -EINVAL if it is not available. + * + * Locking: none (up to the driver) + */ + +static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) +{ + int retval = -EINVAL; + + if (tty->ops->tiocmget) { + retval = tty->ops->tiocmget(tty, file); + + if (retval >= 0) + retval = put_user(retval, p); + } + return retval; +} + +/** + * tty_tiocmset - set modem status + * @tty: tty device + * @file: user file pointer + * @cmd: command - clear bits, set bits or set all + * @p: pointer to desired bits + * + * Set the modem status bits from the tty driver if the feature + * is supported. Return -EINVAL if it is not available. + * + * Locking: none (up to the driver) + */ + +static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, + unsigned __user *p) +{ + int retval; + unsigned int set, clear, val; + + if (tty->ops->tiocmset == NULL) + return -EINVAL; + + retval = get_user(val, p); + if (retval) + return retval; + set = clear = 0; + switch (cmd) { + case TIOCMBIS: + set = val; + break; + case TIOCMBIC: + clear = val; + break; + case TIOCMSET: + set = val; + clear = ~val; + break; + } + set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; + clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; + return tty->ops->tiocmset(tty, file, set, clear); +} + +static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) +{ + int retval = -EINVAL; + struct serial_icounter_struct icount; + memset(&icount, 0, sizeof(icount)); + if (tty->ops->get_icount) + retval = tty->ops->get_icount(tty, &icount); + if (retval != 0) + return retval; + if (copy_to_user(arg, &icount, sizeof(icount))) + return -EFAULT; + return 0; +} + +struct tty_struct *tty_pair_get_tty(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + tty = tty->link; + return tty; +} +EXPORT_SYMBOL(tty_pair_get_tty); + +struct tty_struct *tty_pair_get_pty(struct tty_struct *tty) +{ + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + return tty; + return tty->link; +} +EXPORT_SYMBOL(tty_pair_get_pty); + +/* + * Split this up, as gcc can choke on it otherwise.. + */ +long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct tty_struct *tty = file_tty(file); + struct tty_struct *real_tty; + void __user *p = (void __user *)arg; + int retval; + struct tty_ldisc *ld; + struct inode *inode = file->f_dentry->d_inode; + + if (tty_paranoia_check(tty, inode, "tty_ioctl")) + return -EINVAL; + + real_tty = tty_pair_get_tty(tty); + + /* + * Factor out some common prep work + */ + switch (cmd) { + case TIOCSETD: + case TIOCSBRK: + case TIOCCBRK: + case TCSBRK: + case TCSBRKP: + retval = tty_check_change(tty); + if (retval) + return retval; + if (cmd != TIOCCBRK) { + tty_wait_until_sent(tty, 0); + if (signal_pending(current)) + return -EINTR; + } + break; + } + + /* + * Now do the stuff. + */ + switch (cmd) { + case TIOCSTI: + return tiocsti(tty, p); + case TIOCGWINSZ: + return tiocgwinsz(real_tty, p); + case TIOCSWINSZ: + return tiocswinsz(real_tty, p); + case TIOCCONS: + return real_tty != tty ? -EINVAL : tioccons(file); + case FIONBIO: + return fionbio(file, p); + case TIOCEXCL: + set_bit(TTY_EXCLUSIVE, &tty->flags); + return 0; + case TIOCNXCL: + clear_bit(TTY_EXCLUSIVE, &tty->flags); + return 0; + case TIOCNOTTY: + if (current->signal->tty != tty) + return -ENOTTY; + no_tty(); + return 0; + case TIOCSCTTY: + return tiocsctty(tty, arg); + case TIOCGPGRP: + return tiocgpgrp(tty, real_tty, p); + case TIOCSPGRP: + return tiocspgrp(tty, real_tty, p); + case TIOCGSID: + return tiocgsid(tty, real_tty, p); + case TIOCGETD: + return put_user(tty->ldisc->ops->num, (int __user *)p); + case TIOCSETD: + return tiocsetd(tty, p); + /* + * Break handling + */ + case TIOCSBRK: /* Turn break on, unconditionally */ + if (tty->ops->break_ctl) + return tty->ops->break_ctl(tty, -1); + return 0; + case TIOCCBRK: /* Turn break off, unconditionally */ + if (tty->ops->break_ctl) + return tty->ops->break_ctl(tty, 0); + return 0; + case TCSBRK: /* SVID version: non-zero arg --> no break */ + /* non-zero arg means wait for all output data + * to be sent (performed above) but don't send break. + * This is used by the tcdrain() termios function. + */ + if (!arg) + return send_break(tty, 250); + return 0; + case TCSBRKP: /* support for POSIX tcsendbreak() */ + return send_break(tty, arg ? arg*100 : 250); + + case TIOCMGET: + return tty_tiocmget(tty, file, p); + case TIOCMSET: + case TIOCMBIC: + case TIOCMBIS: + return tty_tiocmset(tty, file, cmd, p); + case TIOCGICOUNT: + retval = tty_tiocgicount(tty, p); + /* For the moment allow fall through to the old method */ + if (retval != -EINVAL) + return retval; + break; + case TCFLSH: + switch (arg) { + case TCIFLUSH: + case TCIOFLUSH: + /* flush tty buffer and allow ldisc to process ioctl */ + tty_buffer_flush(tty); + break; + } + break; + } + if (tty->ops->ioctl) { + retval = (tty->ops->ioctl)(tty, file, cmd, arg); + if (retval != -ENOIOCTLCMD) + return retval; + } + ld = tty_ldisc_ref_wait(tty); + retval = -EINVAL; + if (ld->ops->ioctl) { + retval = ld->ops->ioctl(tty, file, cmd, arg); + if (retval == -ENOIOCTLCMD) + retval = -EINVAL; + } + tty_ldisc_deref(ld); + return retval; +} + +#ifdef CONFIG_COMPAT +static long tty_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct inode *inode = file->f_dentry->d_inode; + struct tty_struct *tty = file_tty(file); + struct tty_ldisc *ld; + int retval = -ENOIOCTLCMD; + + if (tty_paranoia_check(tty, inode, "tty_ioctl")) + return -EINVAL; + + if (tty->ops->compat_ioctl) { + retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); + if (retval != -ENOIOCTLCMD) + return retval; + } + + ld = tty_ldisc_ref_wait(tty); + if (ld->ops->compat_ioctl) + retval = ld->ops->compat_ioctl(tty, file, cmd, arg); + tty_ldisc_deref(ld); + + return retval; +} +#endif + +/* + * This implements the "Secure Attention Key" --- the idea is to + * prevent trojan horses by killing all processes associated with this + * tty when the user hits the "Secure Attention Key". Required for + * super-paranoid applications --- see the Orange Book for more details. + * + * This code could be nicer; ideally it should send a HUP, wait a few + * seconds, then send a INT, and then a KILL signal. But you then + * have to coordinate with the init process, since all processes associated + * with the current tty must be dead before the new getty is allowed + * to spawn. + * + * Now, if it would be correct ;-/ The current code has a nasty hole - + * it doesn't catch files in flight. We may send the descriptor to ourselves + * via AF_UNIX socket, close it and later fetch from socket. FIXME. + * + * Nasty bug: do_SAK is being called in interrupt context. This can + * deadlock. We punt it up to process context. AKPM - 16Mar2001 + */ +void __do_SAK(struct tty_struct *tty) +{ +#ifdef TTY_SOFT_SAK + tty_hangup(tty); +#else + struct task_struct *g, *p; + struct pid *session; + int i; + struct file *filp; + struct fdtable *fdt; + + if (!tty) + return; + session = tty->session; + + tty_ldisc_flush(tty); + + tty_driver_flush_buffer(tty); + + read_lock(&tasklist_lock); + /* Kill the entire session */ + do_each_pid_task(session, PIDTYPE_SID, p) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): task_session(p)==tty->session\n", + task_pid_nr(p), p->comm); + send_sig(SIGKILL, p, 1); + } while_each_pid_task(session, PIDTYPE_SID, p); + /* Now kill any processes that happen to have the + * tty open. + */ + do_each_thread(g, p) { + if (p->signal->tty == tty) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): task_session(p)==tty->session\n", + task_pid_nr(p), p->comm); + send_sig(SIGKILL, p, 1); + continue; + } + task_lock(p); + if (p->files) { + /* + * We don't take a ref to the file, so we must + * hold ->file_lock instead. + */ + spin_lock(&p->files->file_lock); + fdt = files_fdtable(p->files); + for (i = 0; i < fdt->max_fds; i++) { + filp = fcheck_files(p->files, i); + if (!filp) + continue; + if (filp->f_op->read == tty_read && + file_tty(filp) == tty) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): fd#%d opened to the tty\n", + task_pid_nr(p), p->comm, i); + force_sig(SIGKILL, p); + break; + } + } + spin_unlock(&p->files->file_lock); + } + task_unlock(p); + } while_each_thread(g, p); + read_unlock(&tasklist_lock); +#endif +} + +static void do_SAK_work(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, SAK_work); + __do_SAK(tty); +} + +/* + * The tq handling here is a little racy - tty->SAK_work may already be queued. + * Fortunately we don't need to worry, because if ->SAK_work is already queued, + * the values which we write to it will be identical to the values which it + * already has. --akpm + */ +void do_SAK(struct tty_struct *tty) +{ + if (!tty) + return; + schedule_work(&tty->SAK_work); +} + +EXPORT_SYMBOL(do_SAK); + +static int dev_match_devt(struct device *dev, void *data) +{ + dev_t *devt = data; + return dev->devt == *devt; +} + +/* Must put_device() after it's unused! */ +static struct device *tty_get_device(struct tty_struct *tty) +{ + dev_t devt = tty_devnum(tty); + return class_find_device(tty_class, NULL, &devt, dev_match_devt); +} + + +/** + * initialize_tty_struct + * @tty: tty to initialize + * + * This subroutine initializes a tty structure that has been newly + * allocated. + * + * Locking: none - tty in question must not be exposed at this point + */ + +void initialize_tty_struct(struct tty_struct *tty, + struct tty_driver *driver, int idx) +{ + memset(tty, 0, sizeof(struct tty_struct)); + kref_init(&tty->kref); + tty->magic = TTY_MAGIC; + tty_ldisc_init(tty); + tty->session = NULL; + tty->pgrp = NULL; + tty->overrun_time = jiffies; + tty->buf.head = tty->buf.tail = NULL; + tty_buffer_init(tty); + mutex_init(&tty->termios_mutex); + mutex_init(&tty->ldisc_mutex); + init_waitqueue_head(&tty->write_wait); + init_waitqueue_head(&tty->read_wait); + INIT_WORK(&tty->hangup_work, do_tty_hangup); + mutex_init(&tty->atomic_read_lock); + mutex_init(&tty->atomic_write_lock); + mutex_init(&tty->output_lock); + mutex_init(&tty->echo_lock); + spin_lock_init(&tty->read_lock); + spin_lock_init(&tty->ctrl_lock); + INIT_LIST_HEAD(&tty->tty_files); + INIT_WORK(&tty->SAK_work, do_SAK_work); + + tty->driver = driver; + tty->ops = driver->ops; + tty->index = idx; + tty_line_name(driver, idx, tty->name); + tty->dev = tty_get_device(tty); +} + +/** + * tty_put_char - write one character to a tty + * @tty: tty + * @ch: character + * + * Write one byte to the tty using the provided put_char method + * if present. Returns the number of characters successfully output. + * + * Note: the specific put_char operation in the driver layer may go + * away soon. Don't call it directly, use this method + */ + +int tty_put_char(struct tty_struct *tty, unsigned char ch) +{ + if (tty->ops->put_char) + return tty->ops->put_char(tty, ch); + return tty->ops->write(tty, &ch, 1); +} +EXPORT_SYMBOL_GPL(tty_put_char); + +struct class *tty_class; + +/** + * tty_register_device - register a tty device + * @driver: the tty driver that describes the tty device + * @index: the index in the tty driver for this tty device + * @device: a struct device that is associated with this tty device. + * This field is optional, if there is no known struct device + * for this tty device it can be set to NULL safely. + * + * Returns a pointer to the struct device for this tty device + * (or ERR_PTR(-EFOO) on error). + * + * This call is required to be made to register an individual tty device + * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If + * that bit is not set, this function should not be called by a tty + * driver. + * + * Locking: ?? + */ + +struct device *tty_register_device(struct tty_driver *driver, unsigned index, + struct device *device) +{ + char name[64]; + dev_t dev = MKDEV(driver->major, driver->minor_start) + index; + + if (index >= driver->num) { + printk(KERN_ERR "Attempt to register invalid tty line number " + " (%d).\n", index); + return ERR_PTR(-EINVAL); + } + + if (driver->type == TTY_DRIVER_TYPE_PTY) + pty_line_name(driver, index, name); + else + tty_line_name(driver, index, name); + + return device_create(tty_class, device, dev, NULL, name); +} +EXPORT_SYMBOL(tty_register_device); + +/** + * tty_unregister_device - unregister a tty device + * @driver: the tty driver that describes the tty device + * @index: the index in the tty driver for this tty device + * + * If a tty device is registered with a call to tty_register_device() then + * this function must be called when the tty device is gone. + * + * Locking: ?? + */ + +void tty_unregister_device(struct tty_driver *driver, unsigned index) +{ + device_destroy(tty_class, + MKDEV(driver->major, driver->minor_start) + index); +} +EXPORT_SYMBOL(tty_unregister_device); + +struct tty_driver *alloc_tty_driver(int lines) +{ + struct tty_driver *driver; + + driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); + if (driver) { + kref_init(&driver->kref); + driver->magic = TTY_DRIVER_MAGIC; + driver->num = lines; + /* later we'll move allocation of tables here */ + } + return driver; +} +EXPORT_SYMBOL(alloc_tty_driver); + +static void destruct_tty_driver(struct kref *kref) +{ + struct tty_driver *driver = container_of(kref, struct tty_driver, kref); + int i; + struct ktermios *tp; + void *p; + + if (driver->flags & TTY_DRIVER_INSTALLED) { + /* + * Free the termios and termios_locked structures because + * we don't want to get memory leaks when modular tty + * drivers are removed from the kernel. + */ + for (i = 0; i < driver->num; i++) { + tp = driver->termios[i]; + if (tp) { + driver->termios[i] = NULL; + kfree(tp); + } + if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) + tty_unregister_device(driver, i); + } + p = driver->ttys; + proc_tty_unregister_driver(driver); + driver->ttys = NULL; + driver->termios = NULL; + kfree(p); + cdev_del(&driver->cdev); + } + kfree(driver); +} + +void tty_driver_kref_put(struct tty_driver *driver) +{ + kref_put(&driver->kref, destruct_tty_driver); +} +EXPORT_SYMBOL(tty_driver_kref_put); + +void tty_set_operations(struct tty_driver *driver, + const struct tty_operations *op) +{ + driver->ops = op; +}; +EXPORT_SYMBOL(tty_set_operations); + +void put_tty_driver(struct tty_driver *d) +{ + tty_driver_kref_put(d); +} +EXPORT_SYMBOL(put_tty_driver); + +/* + * Called by a tty driver to register itself. + */ +int tty_register_driver(struct tty_driver *driver) +{ + int error; + int i; + dev_t dev; + void **p = NULL; + struct device *d; + + if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { + p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL); + if (!p) + return -ENOMEM; + } + + if (!driver->major) { + error = alloc_chrdev_region(&dev, driver->minor_start, + driver->num, driver->name); + if (!error) { + driver->major = MAJOR(dev); + driver->minor_start = MINOR(dev); + } + } else { + dev = MKDEV(driver->major, driver->minor_start); + error = register_chrdev_region(dev, driver->num, driver->name); + } + if (error < 0) { + kfree(p); + return error; + } + + if (p) { + driver->ttys = (struct tty_struct **)p; + driver->termios = (struct ktermios **)(p + driver->num); + } else { + driver->ttys = NULL; + driver->termios = NULL; + } + + cdev_init(&driver->cdev, &tty_fops); + driver->cdev.owner = driver->owner; + error = cdev_add(&driver->cdev, dev, driver->num); + if (error) { + unregister_chrdev_region(dev, driver->num); + driver->ttys = NULL; + driver->termios = NULL; + kfree(p); + return error; + } + + mutex_lock(&tty_mutex); + list_add(&driver->tty_drivers, &tty_drivers); + mutex_unlock(&tty_mutex); + + if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { + for (i = 0; i < driver->num; i++) { + d = tty_register_device(driver, i, NULL); + if (IS_ERR(d)) { + error = PTR_ERR(d); + goto err; + } + } + } + proc_tty_register_driver(driver); + driver->flags |= TTY_DRIVER_INSTALLED; + return 0; + +err: + for (i--; i >= 0; i--) + tty_unregister_device(driver, i); + + mutex_lock(&tty_mutex); + list_del(&driver->tty_drivers); + mutex_unlock(&tty_mutex); + + unregister_chrdev_region(dev, driver->num); + driver->ttys = NULL; + driver->termios = NULL; + kfree(p); + return error; +} + +EXPORT_SYMBOL(tty_register_driver); + +/* + * Called by a tty driver to unregister itself. + */ +int tty_unregister_driver(struct tty_driver *driver) +{ +#if 0 + /* FIXME */ + if (driver->refcount) + return -EBUSY; +#endif + unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), + driver->num); + mutex_lock(&tty_mutex); + list_del(&driver->tty_drivers); + mutex_unlock(&tty_mutex); + return 0; +} + +EXPORT_SYMBOL(tty_unregister_driver); + +dev_t tty_devnum(struct tty_struct *tty) +{ + return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; +} +EXPORT_SYMBOL(tty_devnum); + +void proc_clear_tty(struct task_struct *p) +{ + unsigned long flags; + struct tty_struct *tty; + spin_lock_irqsave(&p->sighand->siglock, flags); + tty = p->signal->tty; + p->signal->tty = NULL; + spin_unlock_irqrestore(&p->sighand->siglock, flags); + tty_kref_put(tty); +} + +/* Called under the sighand lock */ + +static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + if (tty) { + unsigned long flags; + /* We should not have a session or pgrp to put here but.... */ + spin_lock_irqsave(&tty->ctrl_lock, flags); + put_pid(tty->session); + put_pid(tty->pgrp); + tty->pgrp = get_pid(task_pgrp(tsk)); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + tty->session = get_pid(task_session(tsk)); + if (tsk->signal->tty) { + printk(KERN_DEBUG "tty not NULL!!\n"); + tty_kref_put(tsk->signal->tty); + } + } + put_pid(tsk->signal->tty_old_pgrp); + tsk->signal->tty = tty_kref_get(tty); + tsk->signal->tty_old_pgrp = NULL; +} + +static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) +{ + spin_lock_irq(&tsk->sighand->siglock); + __proc_set_tty(tsk, tty); + spin_unlock_irq(&tsk->sighand->siglock); +} + +struct tty_struct *get_current_tty(void) +{ + struct tty_struct *tty; + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + tty = tty_kref_get(current->signal->tty); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + return tty; +} +EXPORT_SYMBOL_GPL(get_current_tty); + +void tty_default_fops(struct file_operations *fops) +{ + *fops = tty_fops; +} + +/* + * Initialize the console device. This is called *early*, so + * we can't necessarily depend on lots of kernel help here. + * Just do some early initializations, and do the complex setup + * later. + */ +void __init console_init(void) +{ + initcall_t *call; + + /* Setup the default TTY line discipline. */ + tty_ldisc_begin(); + + /* + * set up the console device so that later boot sequences can + * inform about problems etc.. + */ + call = __con_initcall_start; + while (call < __con_initcall_end) { + (*call)(); + call++; + } +} + +static char *tty_devnode(struct device *dev, mode_t *mode) +{ + if (!mode) + return NULL; + if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) || + dev->devt == MKDEV(TTYAUX_MAJOR, 2)) + *mode = 0666; + return NULL; +} + +static int __init tty_class_init(void) +{ + tty_class = class_create(THIS_MODULE, "tty"); + if (IS_ERR(tty_class)) + return PTR_ERR(tty_class); + tty_class->devnode = tty_devnode; + return 0; +} + +postcore_initcall(tty_class_init); + +/* 3/2004 jmc: why do these devices exist? */ + +static struct cdev tty_cdev, console_cdev; + +/* + * Ok, now we can initialize the rest of the tty devices and can count + * on memory allocations, interrupts etc.. + */ +int __init tty_init(void) +{ + cdev_init(&tty_cdev, &tty_fops); + if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || + register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) + panic("Couldn't register /dev/tty driver\n"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, + "tty"); + + cdev_init(&console_cdev, &console_fops); + if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || + register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) + panic("Couldn't register /dev/console driver\n"); + device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, + "console"); + +#ifdef CONFIG_VT + vty_init(&console_fops); +#endif + return 0; +} + diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c new file mode 100644 index 00000000000..0c188997145 --- /dev/null +++ b/drivers/tty/tty_ioctl.c @@ -0,0 +1,1179 @@ +/* + * linux/drivers/char/tty_ioctl.c + * + * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds + * + * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines + * which can be dynamically activated and de-activated by the line + * discipline handling modules (like SLIP). + */ + +#include <linux/types.h> +#include <linux/termios.h> +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/major.h> +#include <linux/tty.h> +#include <linux/fcntl.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/bitops.h> +#include <linux/mutex.h> + +#include <asm/io.h> +#include <asm/uaccess.h> +#include <asm/system.h> + +#undef TTY_DEBUG_WAIT_UNTIL_SENT + +#undef DEBUG + +/* + * Internal flag options for termios setting behavior + */ +#define TERMIOS_FLUSH 1 +#define TERMIOS_WAIT 2 +#define TERMIOS_TERMIO 4 +#define TERMIOS_OLD 8 + + +/** + * tty_chars_in_buffer - characters pending + * @tty: terminal + * + * Return the number of bytes of data in the device private + * output queue. If no private method is supplied there is assumed + * to be no queue on the device. + */ + +int tty_chars_in_buffer(struct tty_struct *tty) +{ + if (tty->ops->chars_in_buffer) + return tty->ops->chars_in_buffer(tty); + else + return 0; +} +EXPORT_SYMBOL(tty_chars_in_buffer); + +/** + * tty_write_room - write queue space + * @tty: terminal + * + * Return the number of bytes that can be queued to this device + * at the present time. The result should be treated as a guarantee + * and the driver cannot offer a value it later shrinks by more than + * the number of bytes written. If no method is provided 2K is always + * returned and data may be lost as there will be no flow control. + */ + +int tty_write_room(struct tty_struct *tty) +{ + if (tty->ops->write_room) + return tty->ops->write_room(tty); + return 2048; +} +EXPORT_SYMBOL(tty_write_room); + +/** + * tty_driver_flush_buffer - discard internal buffer + * @tty: terminal + * + * Discard the internal output buffer for this device. If no method + * is provided then either the buffer cannot be hardware flushed or + * there is no buffer driver side. + */ +void tty_driver_flush_buffer(struct tty_struct *tty) +{ + if (tty->ops->flush_buffer) + tty->ops->flush_buffer(tty); +} +EXPORT_SYMBOL(tty_driver_flush_buffer); + +/** + * tty_throttle - flow control + * @tty: terminal + * + * Indicate that a tty should stop transmitting data down the stack. + * Takes the termios mutex to protect against parallel throttle/unthrottle + * and also to ensure the driver can consistently reference its own + * termios data at this point when implementing software flow control. + */ + +void tty_throttle(struct tty_struct *tty) +{ + mutex_lock(&tty->termios_mutex); + /* check TTY_THROTTLED first so it indicates our state */ + if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) && + tty->ops->throttle) + tty->ops->throttle(tty); + mutex_unlock(&tty->termios_mutex); +} +EXPORT_SYMBOL(tty_throttle); + +/** + * tty_unthrottle - flow control + * @tty: terminal + * + * Indicate that a tty may continue transmitting data down the stack. + * Takes the termios mutex to protect against parallel throttle/unthrottle + * and also to ensure the driver can consistently reference its own + * termios data at this point when implementing software flow control. + * + * Drivers should however remember that the stack can issue a throttle, + * then change flow control method, then unthrottle. + */ + +void tty_unthrottle(struct tty_struct *tty) +{ + mutex_lock(&tty->termios_mutex); + if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) && + tty->ops->unthrottle) + tty->ops->unthrottle(tty); + mutex_unlock(&tty->termios_mutex); +} +EXPORT_SYMBOL(tty_unthrottle); + +/** + * tty_wait_until_sent - wait for I/O to finish + * @tty: tty we are waiting for + * @timeout: how long we will wait + * + * Wait for characters pending in a tty driver to hit the wire, or + * for a timeout to occur (eg due to flow control) + * + * Locking: none + */ + +void tty_wait_until_sent(struct tty_struct *tty, long timeout) +{ +#ifdef TTY_DEBUG_WAIT_UNTIL_SENT + char buf[64]; + + printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf)); +#endif + if (!timeout) + timeout = MAX_SCHEDULE_TIMEOUT; + if (wait_event_interruptible_timeout(tty->write_wait, + !tty_chars_in_buffer(tty), timeout) >= 0) { + if (tty->ops->wait_until_sent) + tty->ops->wait_until_sent(tty, timeout); + } +} +EXPORT_SYMBOL(tty_wait_until_sent); + + +/* + * Termios Helper Methods + */ + +static void unset_locked_termios(struct ktermios *termios, + struct ktermios *old, + struct ktermios *locked) +{ + int i; + +#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z))) + + if (!locked) { + printk(KERN_WARNING "Warning?!? termios_locked is NULL.\n"); + return; + } + + NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag); + NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag); + NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag); + NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag); + termios->c_line = locked->c_line ? old->c_line : termios->c_line; + for (i = 0; i < NCCS; i++) + termios->c_cc[i] = locked->c_cc[i] ? + old->c_cc[i] : termios->c_cc[i]; + /* FIXME: What should we do for i/ospeed */ +} + +/* + * Routine which returns the baud rate of the tty + * + * Note that the baud_table needs to be kept in sync with the + * include/asm/termbits.h file. + */ +static const speed_t baud_table[] = { + 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, + 9600, 19200, 38400, 57600, 115200, 230400, 460800, +#ifdef __sparc__ + 76800, 153600, 307200, 614400, 921600 +#else + 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, + 2500000, 3000000, 3500000, 4000000 +#endif +}; + +#ifndef __sparc__ +static const tcflag_t baud_bits[] = { + B0, B50, B75, B110, B134, B150, B200, B300, B600, + B1200, B1800, B2400, B4800, B9600, B19200, B38400, + B57600, B115200, B230400, B460800, B500000, B576000, + B921600, B1000000, B1152000, B1500000, B2000000, B2500000, + B3000000, B3500000, B4000000 +}; +#else +static const tcflag_t baud_bits[] = { + B0, B50, B75, B110, B134, B150, B200, B300, B600, + B1200, B1800, B2400, B4800, B9600, B19200, B38400, + B57600, B115200, B230400, B460800, B76800, B153600, + B307200, B614400, B921600 +}; +#endif + +static int n_baud_table = ARRAY_SIZE(baud_table); + +/** + * tty_termios_baud_rate + * @termios: termios structure + * + * Convert termios baud rate data into a speed. This should be called + * with the termios lock held if this termios is a terminal termios + * structure. May change the termios data. Device drivers can call this + * function but should use ->c_[io]speed directly as they are updated. + * + * Locking: none + */ + +speed_t tty_termios_baud_rate(struct ktermios *termios) +{ + unsigned int cbaud; + + cbaud = termios->c_cflag & CBAUD; + +#ifdef BOTHER + /* Magic token for arbitary speed via c_ispeed/c_ospeed */ + if (cbaud == BOTHER) + return termios->c_ospeed; +#endif + if (cbaud & CBAUDEX) { + cbaud &= ~CBAUDEX; + + if (cbaud < 1 || cbaud + 15 > n_baud_table) + termios->c_cflag &= ~CBAUDEX; + else + cbaud += 15; + } + return baud_table[cbaud]; +} +EXPORT_SYMBOL(tty_termios_baud_rate); + +/** + * tty_termios_input_baud_rate + * @termios: termios structure + * + * Convert termios baud rate data into a speed. This should be called + * with the termios lock held if this termios is a terminal termios + * structure. May change the termios data. Device drivers can call this + * function but should use ->c_[io]speed directly as they are updated. + * + * Locking: none + */ + +speed_t tty_termios_input_baud_rate(struct ktermios *termios) +{ +#ifdef IBSHIFT + unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD; + + if (cbaud == B0) + return tty_termios_baud_rate(termios); + + /* Magic token for arbitary speed via c_ispeed*/ + if (cbaud == BOTHER) + return termios->c_ispeed; + + if (cbaud & CBAUDEX) { + cbaud &= ~CBAUDEX; + + if (cbaud < 1 || cbaud + 15 > n_baud_table) + termios->c_cflag &= ~(CBAUDEX << IBSHIFT); + else + cbaud += 15; + } + return baud_table[cbaud]; +#else + return tty_termios_baud_rate(termios); +#endif +} +EXPORT_SYMBOL(tty_termios_input_baud_rate); + +/** + * tty_termios_encode_baud_rate + * @termios: ktermios structure holding user requested state + * @ispeed: input speed + * @ospeed: output speed + * + * Encode the speeds set into the passed termios structure. This is + * used as a library helper for drivers os that they can report back + * the actual speed selected when it differs from the speed requested + * + * For maximal back compatibility with legacy SYS5/POSIX *nix behaviour + * we need to carefully set the bits when the user does not get the + * desired speed. We allow small margins and preserve as much of possible + * of the input intent to keep compatibility. + * + * Locking: Caller should hold termios lock. This is already held + * when calling this function from the driver termios handler. + * + * The ifdefs deal with platforms whose owners have yet to update them + * and will all go away once this is done. + */ + +void tty_termios_encode_baud_rate(struct ktermios *termios, + speed_t ibaud, speed_t obaud) +{ + int i = 0; + int ifound = -1, ofound = -1; + int iclose = ibaud/50, oclose = obaud/50; + int ibinput = 0; + + if (obaud == 0) /* CD dropped */ + ibaud = 0; /* Clear ibaud to be sure */ + + termios->c_ispeed = ibaud; + termios->c_ospeed = obaud; + +#ifdef BOTHER + /* If the user asked for a precise weird speed give a precise weird + answer. If they asked for a Bfoo speed they many have problems + digesting non-exact replies so fuzz a bit */ + + if ((termios->c_cflag & CBAUD) == BOTHER) + oclose = 0; + if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER) + iclose = 0; + if ((termios->c_cflag >> IBSHIFT) & CBAUD) + ibinput = 1; /* An input speed was specified */ +#endif + termios->c_cflag &= ~CBAUD; + + /* + * Our goal is to find a close match to the standard baud rate + * returned. Walk the baud rate table and if we get a very close + * match then report back the speed as a POSIX Bxxxx value by + * preference + */ + + do { + if (obaud - oclose <= baud_table[i] && + obaud + oclose >= baud_table[i]) { + termios->c_cflag |= baud_bits[i]; + ofound = i; + } + if (ibaud - iclose <= baud_table[i] && + ibaud + iclose >= baud_table[i]) { + /* For the case input == output don't set IBAUD bits + if the user didn't do so */ + if (ofound == i && !ibinput) + ifound = i; +#ifdef IBSHIFT + else { + ifound = i; + termios->c_cflag |= (baud_bits[i] << IBSHIFT); + } +#endif + } + } while (++i < n_baud_table); + + /* + * If we found no match then use BOTHER if provided or warn + * the user their platform maintainer needs to wake up if not. + */ +#ifdef BOTHER + if (ofound == -1) + termios->c_cflag |= BOTHER; + /* Set exact input bits only if the input and output differ or the + user already did */ + if (ifound == -1 && (ibaud != obaud || ibinput)) + termios->c_cflag |= (BOTHER << IBSHIFT); +#else + if (ifound == -1 || ofound == -1) { + printk_once(KERN_WARNING "tty: Unable to return correct " + "speed data as your architecture needs updating.\n"); + } +#endif +} +EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate); + +/** + * tty_encode_baud_rate - set baud rate of the tty + * @ibaud: input baud rate + * @obad: output baud rate + * + * Update the current termios data for the tty with the new speed + * settings. The caller must hold the termios_mutex for the tty in + * question. + */ + +void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud) +{ + tty_termios_encode_baud_rate(tty->termios, ibaud, obaud); +} +EXPORT_SYMBOL_GPL(tty_encode_baud_rate); + +/** + * tty_get_baud_rate - get tty bit rates + * @tty: tty to query + * + * Returns the baud rate as an integer for this terminal. The + * termios lock must be held by the caller and the terminal bit + * flags may be updated. + * + * Locking: none + */ + +speed_t tty_get_baud_rate(struct tty_struct *tty) +{ + speed_t baud = tty_termios_baud_rate(tty->termios); + + if (baud == 38400 && tty->alt_speed) { + if (!tty->warned) { + printk(KERN_WARNING "Use of setserial/setrocket to " + "set SPD_* flags is deprecated\n"); + tty->warned = 1; + } + baud = tty->alt_speed; + } + + return baud; +} +EXPORT_SYMBOL(tty_get_baud_rate); + +/** + * tty_termios_copy_hw - copy hardware settings + * @new: New termios + * @old: Old termios + * + * Propogate the hardware specific terminal setting bits from + * the old termios structure to the new one. This is used in cases + * where the hardware does not support reconfiguration or as a helper + * in some cases where only minimal reconfiguration is supported + */ + +void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old) +{ + /* The bits a dumb device handles in software. Smart devices need + to always provide a set_termios method */ + new->c_cflag &= HUPCL | CREAD | CLOCAL; + new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL); + new->c_ispeed = old->c_ispeed; + new->c_ospeed = old->c_ospeed; +} +EXPORT_SYMBOL(tty_termios_copy_hw); + +/** + * tty_termios_hw_change - check for setting change + * @a: termios + * @b: termios to compare + * + * Check if any of the bits that affect a dumb device have changed + * between the two termios structures, or a speed change is needed. + */ + +int tty_termios_hw_change(struct ktermios *a, struct ktermios *b) +{ + if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed) + return 1; + if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL)) + return 1; + return 0; +} +EXPORT_SYMBOL(tty_termios_hw_change); + +/** + * change_termios - update termios values + * @tty: tty to update + * @new_termios: desired new value + * + * Perform updates to the termios values set on this terminal. There + * is a bit of layering violation here with n_tty in terms of the + * internal knowledge of this function. + * + * Locking: termios_mutex + */ + +static void change_termios(struct tty_struct *tty, struct ktermios *new_termios) +{ + struct ktermios old_termios; + struct tty_ldisc *ld; + unsigned long flags; + + /* + * Perform the actual termios internal changes under lock. + */ + + + /* FIXME: we need to decide on some locking/ordering semantics + for the set_termios notification eventually */ + mutex_lock(&tty->termios_mutex); + old_termios = *tty->termios; + *tty->termios = *new_termios; + unset_locked_termios(tty->termios, &old_termios, tty->termios_locked); + + /* See if packet mode change of state. */ + if (tty->link && tty->link->packet) { + int extproc = (old_termios.c_lflag & EXTPROC) | + (tty->termios->c_lflag & EXTPROC); + int old_flow = ((old_termios.c_iflag & IXON) && + (old_termios.c_cc[VSTOP] == '\023') && + (old_termios.c_cc[VSTART] == '\021')); + int new_flow = (I_IXON(tty) && + STOP_CHAR(tty) == '\023' && + START_CHAR(tty) == '\021'); + if ((old_flow != new_flow) || extproc) { + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (old_flow != new_flow) { + tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); + if (new_flow) + tty->ctrl_status |= TIOCPKT_DOSTOP; + else + tty->ctrl_status |= TIOCPKT_NOSTOP; + } + if (extproc) + tty->ctrl_status |= TIOCPKT_IOCTL; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + wake_up_interruptible(&tty->link->read_wait); + } + } + + if (tty->ops->set_termios) + (*tty->ops->set_termios)(tty, &old_termios); + else + tty_termios_copy_hw(tty->termios, &old_termios); + + ld = tty_ldisc_ref(tty); + if (ld != NULL) { + if (ld->ops->set_termios) + (ld->ops->set_termios)(tty, &old_termios); + tty_ldisc_deref(ld); + } + mutex_unlock(&tty->termios_mutex); +} + +/** + * set_termios - set termios values for a tty + * @tty: terminal device + * @arg: user data + * @opt: option information + * + * Helper function to prepare termios data and run necessary other + * functions before using change_termios to do the actual changes. + * + * Locking: + * Called functions take ldisc and termios_mutex locks + */ + +static int set_termios(struct tty_struct *tty, void __user *arg, int opt) +{ + struct ktermios tmp_termios; + struct tty_ldisc *ld; + int retval = tty_check_change(tty); + + if (retval) + return retval; + + mutex_lock(&tty->termios_mutex); + memcpy(&tmp_termios, tty->termios, sizeof(struct ktermios)); + mutex_unlock(&tty->termios_mutex); + + if (opt & TERMIOS_TERMIO) { + if (user_termio_to_kernel_termios(&tmp_termios, + (struct termio __user *)arg)) + return -EFAULT; +#ifdef TCGETS2 + } else if (opt & TERMIOS_OLD) { + if (user_termios_to_kernel_termios_1(&tmp_termios, + (struct termios __user *)arg)) + return -EFAULT; + } else { + if (user_termios_to_kernel_termios(&tmp_termios, + (struct termios2 __user *)arg)) + return -EFAULT; + } +#else + } else if (user_termios_to_kernel_termios(&tmp_termios, + (struct termios __user *)arg)) + return -EFAULT; +#endif + + /* If old style Bfoo values are used then load c_ispeed/c_ospeed + * with the real speed so its unconditionally usable */ + tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios); + tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios); + + ld = tty_ldisc_ref(tty); + + if (ld != NULL) { + if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_ldisc_deref(ld); + } + + if (opt & TERMIOS_WAIT) { + tty_wait_until_sent(tty, 0); + if (signal_pending(current)) + return -EINTR; + } + + change_termios(tty, &tmp_termios); + + /* FIXME: Arguably if tmp_termios == tty->termios AND the + actual requested termios was not tmp_termios then we may + want to return an error as no user requested change has + succeeded */ + return 0; +} + +static void copy_termios(struct tty_struct *tty, struct ktermios *kterm) +{ + mutex_lock(&tty->termios_mutex); + memcpy(kterm, tty->termios, sizeof(struct ktermios)); + mutex_unlock(&tty->termios_mutex); +} + +static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm) +{ + mutex_lock(&tty->termios_mutex); + memcpy(kterm, tty->termios_locked, sizeof(struct ktermios)); + mutex_unlock(&tty->termios_mutex); +} + +static int get_termio(struct tty_struct *tty, struct termio __user *termio) +{ + struct ktermios kterm; + copy_termios(tty, &kterm); + if (kernel_termios_to_user_termio(termio, &kterm)) + return -EFAULT; + return 0; +} + + +#ifdef TCGETX + +/** + * set_termiox - set termiox fields if possible + * @tty: terminal + * @arg: termiox structure from user + * @opt: option flags for ioctl type + * + * Implement the device calling points for the SYS5 termiox ioctl + * interface in Linux + */ + +static int set_termiox(struct tty_struct *tty, void __user *arg, int opt) +{ + struct termiox tnew; + struct tty_ldisc *ld; + + if (tty->termiox == NULL) + return -EINVAL; + if (copy_from_user(&tnew, arg, sizeof(struct termiox))) + return -EFAULT; + + ld = tty_ldisc_ref(tty); + if (ld != NULL) { + if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_ldisc_deref(ld); + } + if (opt & TERMIOS_WAIT) { + tty_wait_until_sent(tty, 0); + if (signal_pending(current)) + return -EINTR; + } + + mutex_lock(&tty->termios_mutex); + if (tty->ops->set_termiox) + tty->ops->set_termiox(tty, &tnew); + mutex_unlock(&tty->termios_mutex); + return 0; +} + +#endif + + +#ifdef TIOCGETP +/* + * These are deprecated, but there is limited support.. + * + * The "sg_flags" translation is a joke.. + */ +static int get_sgflags(struct tty_struct *tty) +{ + int flags = 0; + + if (!(tty->termios->c_lflag & ICANON)) { + if (tty->termios->c_lflag & ISIG) + flags |= 0x02; /* cbreak */ + else + flags |= 0x20; /* raw */ + } + if (tty->termios->c_lflag & ECHO) + flags |= 0x08; /* echo */ + if (tty->termios->c_oflag & OPOST) + if (tty->termios->c_oflag & ONLCR) + flags |= 0x10; /* crmod */ + return flags; +} + +static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb) +{ + struct sgttyb tmp; + + mutex_lock(&tty->termios_mutex); + tmp.sg_ispeed = tty->termios->c_ispeed; + tmp.sg_ospeed = tty->termios->c_ospeed; + tmp.sg_erase = tty->termios->c_cc[VERASE]; + tmp.sg_kill = tty->termios->c_cc[VKILL]; + tmp.sg_flags = get_sgflags(tty); + mutex_unlock(&tty->termios_mutex); + + return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0; +} + +static void set_sgflags(struct ktermios *termios, int flags) +{ + termios->c_iflag = ICRNL | IXON; + termios->c_oflag = 0; + termios->c_lflag = ISIG | ICANON; + if (flags & 0x02) { /* cbreak */ + termios->c_iflag = 0; + termios->c_lflag &= ~ICANON; + } + if (flags & 0x08) { /* echo */ + termios->c_lflag |= ECHO | ECHOE | ECHOK | + ECHOCTL | ECHOKE | IEXTEN; + } + if (flags & 0x10) { /* crmod */ + termios->c_oflag |= OPOST | ONLCR; + } + if (flags & 0x20) { /* raw */ + termios->c_iflag = 0; + termios->c_lflag &= ~(ISIG | ICANON); + } + if (!(termios->c_lflag & ICANON)) { + termios->c_cc[VMIN] = 1; + termios->c_cc[VTIME] = 0; + } +} + +/** + * set_sgttyb - set legacy terminal values + * @tty: tty structure + * @sgttyb: pointer to old style terminal structure + * + * Updates a terminal from the legacy BSD style terminal information + * structure. + * + * Locking: termios_mutex + */ + +static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb) +{ + int retval; + struct sgttyb tmp; + struct ktermios termios; + + retval = tty_check_change(tty); + if (retval) + return retval; + + if (copy_from_user(&tmp, sgttyb, sizeof(tmp))) + return -EFAULT; + + mutex_lock(&tty->termios_mutex); + termios = *tty->termios; + termios.c_cc[VERASE] = tmp.sg_erase; + termios.c_cc[VKILL] = tmp.sg_kill; + set_sgflags(&termios, tmp.sg_flags); + /* Try and encode into Bfoo format */ +#ifdef BOTHER + tty_termios_encode_baud_rate(&termios, termios.c_ispeed, + termios.c_ospeed); +#endif + mutex_unlock(&tty->termios_mutex); + change_termios(tty, &termios); + return 0; +} +#endif + +#ifdef TIOCGETC +static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars) +{ + struct tchars tmp; + + mutex_lock(&tty->termios_mutex); + tmp.t_intrc = tty->termios->c_cc[VINTR]; + tmp.t_quitc = tty->termios->c_cc[VQUIT]; + tmp.t_startc = tty->termios->c_cc[VSTART]; + tmp.t_stopc = tty->termios->c_cc[VSTOP]; + tmp.t_eofc = tty->termios->c_cc[VEOF]; + tmp.t_brkc = tty->termios->c_cc[VEOL2]; /* what is brkc anyway? */ + mutex_unlock(&tty->termios_mutex); + return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; +} + +static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars) +{ + struct tchars tmp; + + if (copy_from_user(&tmp, tchars, sizeof(tmp))) + return -EFAULT; + mutex_lock(&tty->termios_mutex); + tty->termios->c_cc[VINTR] = tmp.t_intrc; + tty->termios->c_cc[VQUIT] = tmp.t_quitc; + tty->termios->c_cc[VSTART] = tmp.t_startc; + tty->termios->c_cc[VSTOP] = tmp.t_stopc; + tty->termios->c_cc[VEOF] = tmp.t_eofc; + tty->termios->c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */ + mutex_unlock(&tty->termios_mutex); + return 0; +} +#endif + +#ifdef TIOCGLTC +static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars) +{ + struct ltchars tmp; + + mutex_lock(&tty->termios_mutex); + tmp.t_suspc = tty->termios->c_cc[VSUSP]; + /* what is dsuspc anyway? */ + tmp.t_dsuspc = tty->termios->c_cc[VSUSP]; + tmp.t_rprntc = tty->termios->c_cc[VREPRINT]; + /* what is flushc anyway? */ + tmp.t_flushc = tty->termios->c_cc[VEOL2]; + tmp.t_werasc = tty->termios->c_cc[VWERASE]; + tmp.t_lnextc = tty->termios->c_cc[VLNEXT]; + mutex_unlock(&tty->termios_mutex); + return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; +} + +static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars) +{ + struct ltchars tmp; + + if (copy_from_user(&tmp, ltchars, sizeof(tmp))) + return -EFAULT; + + mutex_lock(&tty->termios_mutex); + tty->termios->c_cc[VSUSP] = tmp.t_suspc; + /* what is dsuspc anyway? */ + tty->termios->c_cc[VEOL2] = tmp.t_dsuspc; + tty->termios->c_cc[VREPRINT] = tmp.t_rprntc; + /* what is flushc anyway? */ + tty->termios->c_cc[VEOL2] = tmp.t_flushc; + tty->termios->c_cc[VWERASE] = tmp.t_werasc; + tty->termios->c_cc[VLNEXT] = tmp.t_lnextc; + mutex_unlock(&tty->termios_mutex); + return 0; +} +#endif + +/** + * send_prio_char - send priority character + * + * Send a high priority character to the tty even if stopped + * + * Locking: none for xchar method, write ordering for write method. + */ + +static int send_prio_char(struct tty_struct *tty, char ch) +{ + int was_stopped = tty->stopped; + + if (tty->ops->send_xchar) { + tty->ops->send_xchar(tty, ch); + return 0; + } + + if (tty_write_lock(tty, 0) < 0) + return -ERESTARTSYS; + + if (was_stopped) + start_tty(tty); + tty->ops->write(tty, &ch, 1); + if (was_stopped) + stop_tty(tty); + tty_write_unlock(tty); + return 0; +} + +/** + * tty_change_softcar - carrier change ioctl helper + * @tty: tty to update + * @arg: enable/disable CLOCAL + * + * Perform a change to the CLOCAL state and call into the driver + * layer to make it visible. All done with the termios mutex + */ + +static int tty_change_softcar(struct tty_struct *tty, int arg) +{ + int ret = 0; + int bit = arg ? CLOCAL : 0; + struct ktermios old; + + mutex_lock(&tty->termios_mutex); + old = *tty->termios; + tty->termios->c_cflag &= ~CLOCAL; + tty->termios->c_cflag |= bit; + if (tty->ops->set_termios) + tty->ops->set_termios(tty, &old); + if ((tty->termios->c_cflag & CLOCAL) != bit) + ret = -EINVAL; + mutex_unlock(&tty->termios_mutex); + return ret; +} + +/** + * tty_mode_ioctl - mode related ioctls + * @tty: tty for the ioctl + * @file: file pointer for the tty + * @cmd: command + * @arg: ioctl argument + * + * Perform non line discipline specific mode control ioctls. This + * is designed to be called by line disciplines to ensure they provide + * consistent mode setting. + */ + +int tty_mode_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct tty_struct *real_tty; + void __user *p = (void __user *)arg; + int ret = 0; + struct ktermios kterm; + + if (tty->driver->type == TTY_DRIVER_TYPE_PTY && + tty->driver->subtype == PTY_TYPE_MASTER) + real_tty = tty->link; + else + real_tty = tty; + + switch (cmd) { +#ifdef TIOCGETP + case TIOCGETP: + return get_sgttyb(real_tty, (struct sgttyb __user *) arg); + case TIOCSETP: + case TIOCSETN: + return set_sgttyb(real_tty, (struct sgttyb __user *) arg); +#endif +#ifdef TIOCGETC + case TIOCGETC: + return get_tchars(real_tty, p); + case TIOCSETC: + return set_tchars(real_tty, p); +#endif +#ifdef TIOCGLTC + case TIOCGLTC: + return get_ltchars(real_tty, p); + case TIOCSLTC: + return set_ltchars(real_tty, p); +#endif + case TCSETSF: + return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD); + case TCSETSW: + return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD); + case TCSETS: + return set_termios(real_tty, p, TERMIOS_OLD); +#ifndef TCGETS2 + case TCGETS: + copy_termios(real_tty, &kterm); + if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm)) + ret = -EFAULT; + return ret; +#else + case TCGETS: + copy_termios(real_tty, &kterm); + if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm)) + ret = -EFAULT; + return ret; + case TCGETS2: + copy_termios(real_tty, &kterm); + if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm)) + ret = -EFAULT; + return ret; + case TCSETSF2: + return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT); + case TCSETSW2: + return set_termios(real_tty, p, TERMIOS_WAIT); + case TCSETS2: + return set_termios(real_tty, p, 0); +#endif + case TCGETA: + return get_termio(real_tty, p); + case TCSETAF: + return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO); + case TCSETAW: + return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO); + case TCSETA: + return set_termios(real_tty, p, TERMIOS_TERMIO); +#ifndef TCGETS2 + case TIOCGLCKTRMIOS: + copy_termios_locked(real_tty, &kterm); + if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm)) + ret = -EFAULT; + return ret; + case TIOCSLCKTRMIOS: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + copy_termios_locked(real_tty, &kterm); + if (user_termios_to_kernel_termios(&kterm, + (struct termios __user *) arg)) + return -EFAULT; + mutex_lock(&real_tty->termios_mutex); + memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios)); + mutex_unlock(&real_tty->termios_mutex); + return 0; +#else + case TIOCGLCKTRMIOS: + copy_termios_locked(real_tty, &kterm); + if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm)) + ret = -EFAULT; + return ret; + case TIOCSLCKTRMIOS: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + copy_termios_locked(real_tty, &kterm); + if (user_termios_to_kernel_termios_1(&kterm, + (struct termios __user *) arg)) + return -EFAULT; + mutex_lock(&real_tty->termios_mutex); + memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios)); + mutex_unlock(&real_tty->termios_mutex); + return ret; +#endif +#ifdef TCGETX + case TCGETX: { + struct termiox ktermx; + if (real_tty->termiox == NULL) + return -EINVAL; + mutex_lock(&real_tty->termios_mutex); + memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox)); + mutex_unlock(&real_tty->termios_mutex); + if (copy_to_user(p, &ktermx, sizeof(struct termiox))) + ret = -EFAULT; + return ret; + } + case TCSETX: + return set_termiox(real_tty, p, 0); + case TCSETXW: + return set_termiox(real_tty, p, TERMIOS_WAIT); + case TCSETXF: + return set_termiox(real_tty, p, TERMIOS_FLUSH); +#endif + case TIOCGSOFTCAR: + copy_termios(real_tty, &kterm); + ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0, + (int __user *)arg); + return ret; + case TIOCSSOFTCAR: + if (get_user(arg, (unsigned int __user *) arg)) + return -EFAULT; + return tty_change_softcar(real_tty, arg); + default: + return -ENOIOCTLCMD; + } +} +EXPORT_SYMBOL_GPL(tty_mode_ioctl); + +int tty_perform_flush(struct tty_struct *tty, unsigned long arg) +{ + struct tty_ldisc *ld; + int retval = tty_check_change(tty); + if (retval) + return retval; + + ld = tty_ldisc_ref_wait(tty); + switch (arg) { + case TCIFLUSH: + if (ld && ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + break; + case TCIOFLUSH: + if (ld && ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + /* fall through */ + case TCOFLUSH: + tty_driver_flush_buffer(tty); + break; + default: + tty_ldisc_deref(ld); + return -EINVAL; + } + tty_ldisc_deref(ld); + return 0; +} +EXPORT_SYMBOL_GPL(tty_perform_flush); + +int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + unsigned long flags; + int retval; + + switch (cmd) { + case TCXONC: + retval = tty_check_change(tty); + if (retval) + return retval; + switch (arg) { + case TCOOFF: + if (!tty->flow_stopped) { + tty->flow_stopped = 1; + stop_tty(tty); + } + break; + case TCOON: + if (tty->flow_stopped) { + tty->flow_stopped = 0; + start_tty(tty); + } + break; + case TCIOFF: + if (STOP_CHAR(tty) != __DISABLED_CHAR) + return send_prio_char(tty, STOP_CHAR(tty)); + break; + case TCION: + if (START_CHAR(tty) != __DISABLED_CHAR) + return send_prio_char(tty, START_CHAR(tty)); + break; + default: + return -EINVAL; + } + return 0; + case TCFLSH: + return tty_perform_flush(tty, arg); + case TIOCPKT: + { + int pktmode; + + if (tty->driver->type != TTY_DRIVER_TYPE_PTY || + tty->driver->subtype != PTY_TYPE_MASTER) + return -ENOTTY; + if (get_user(pktmode, (int __user *) arg)) + return -EFAULT; + spin_lock_irqsave(&tty->ctrl_lock, flags); + if (pktmode) { + if (!tty->packet) { + tty->packet = 1; + tty->link->ctrl_status = 0; + } + } else + tty->packet = 0; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + return 0; + } + default: + /* Try the mode commands */ + return tty_mode_ioctl(tty, file, cmd, arg); + } +} +EXPORT_SYMBOL(n_tty_ioctl_helper); diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c new file mode 100644 index 00000000000..412f9775d19 --- /dev/null +++ b/drivers/tty/tty_ldisc.c @@ -0,0 +1,915 @@ +#include <linux/types.h> +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/signal.h> +#include <linux/fcntl.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/devpts_fs.h> +#include <linux/file.h> +#include <linux/console.h> +#include <linux/timer.h> +#include <linux/ctype.h> +#include <linux/kd.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/proc_fs.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/seq_file.h> + +#include <linux/uaccess.h> +#include <asm/system.h> + +#include <linux/kbd_kern.h> +#include <linux/vt_kern.h> +#include <linux/selection.h> + +#include <linux/smp_lock.h> /* For the moment */ + +#include <linux/kmod.h> +#include <linux/nsproxy.h> + +/* + * This guards the refcounted line discipline lists. The lock + * must be taken with irqs off because there are hangup path + * callers who will do ldisc lookups and cannot sleep. + */ + +static DEFINE_SPINLOCK(tty_ldisc_lock); +static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); +/* Line disc dispatch table */ +static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS]; + +static inline struct tty_ldisc *get_ldisc(struct tty_ldisc *ld) +{ + if (ld) + atomic_inc(&ld->users); + return ld; +} + +static void put_ldisc(struct tty_ldisc *ld) +{ + unsigned long flags; + + if (WARN_ON_ONCE(!ld)) + return; + + /* + * If this is the last user, free the ldisc, and + * release the ldisc ops. + * + * We really want an "atomic_dec_and_lock_irqsave()", + * but we don't have it, so this does it by hand. + */ + local_irq_save(flags); + if (atomic_dec_and_lock(&ld->users, &tty_ldisc_lock)) { + struct tty_ldisc_ops *ldo = ld->ops; + + ldo->refcount--; + module_put(ldo->owner); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + kfree(ld); + return; + } + local_irq_restore(flags); +} + +/** + * tty_register_ldisc - install a line discipline + * @disc: ldisc number + * @new_ldisc: pointer to the ldisc object + * + * Installs a new line discipline into the kernel. The discipline + * is set up as unreferenced and then made available to the kernel + * from this point onwards. + * + * Locking: + * takes tty_ldisc_lock to guard against ldisc races + */ + +int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc) +{ + unsigned long flags; + int ret = 0; + + if (disc < N_TTY || disc >= NR_LDISCS) + return -EINVAL; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + tty_ldiscs[disc] = new_ldisc; + new_ldisc->num = disc; + new_ldisc->refcount = 0; + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + return ret; +} +EXPORT_SYMBOL(tty_register_ldisc); + +/** + * tty_unregister_ldisc - unload a line discipline + * @disc: ldisc number + * @new_ldisc: pointer to the ldisc object + * + * Remove a line discipline from the kernel providing it is not + * currently in use. + * + * Locking: + * takes tty_ldisc_lock to guard against ldisc races + */ + +int tty_unregister_ldisc(int disc) +{ + unsigned long flags; + int ret = 0; + + if (disc < N_TTY || disc >= NR_LDISCS) + return -EINVAL; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if (tty_ldiscs[disc]->refcount) + ret = -EBUSY; + else + tty_ldiscs[disc] = NULL; + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + return ret; +} +EXPORT_SYMBOL(tty_unregister_ldisc); + +static struct tty_ldisc_ops *get_ldops(int disc) +{ + unsigned long flags; + struct tty_ldisc_ops *ldops, *ret; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ret = ERR_PTR(-EINVAL); + ldops = tty_ldiscs[disc]; + if (ldops) { + ret = ERR_PTR(-EAGAIN); + if (try_module_get(ldops->owner)) { + ldops->refcount++; + ret = ldops; + } + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ret; +} + +static void put_ldops(struct tty_ldisc_ops *ldops) +{ + unsigned long flags; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ldops->refcount--; + module_put(ldops->owner); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +/** + * tty_ldisc_get - take a reference to an ldisc + * @disc: ldisc number + * + * Takes a reference to a line discipline. Deals with refcounts and + * module locking counts. Returns NULL if the discipline is not available. + * Returns a pointer to the discipline and bumps the ref count if it is + * available + * + * Locking: + * takes tty_ldisc_lock to guard against ldisc races + */ + +static struct tty_ldisc *tty_ldisc_get(int disc) +{ + struct tty_ldisc *ld; + struct tty_ldisc_ops *ldops; + + if (disc < N_TTY || disc >= NR_LDISCS) + return ERR_PTR(-EINVAL); + + /* + * Get the ldisc ops - we may need to request them to be loaded + * dynamically and try again. + */ + ldops = get_ldops(disc); + if (IS_ERR(ldops)) { + request_module("tty-ldisc-%d", disc); + ldops = get_ldops(disc); + if (IS_ERR(ldops)) + return ERR_CAST(ldops); + } + + ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL); + if (ld == NULL) { + put_ldops(ldops); + return ERR_PTR(-ENOMEM); + } + + ld->ops = ldops; + atomic_set(&ld->users, 1); + return ld; +} + +static void *tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos) +{ + return (*pos < NR_LDISCS) ? pos : NULL; +} + +static void *tty_ldiscs_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return (*pos < NR_LDISCS) ? pos : NULL; +} + +static void tty_ldiscs_seq_stop(struct seq_file *m, void *v) +{ +} + +static int tty_ldiscs_seq_show(struct seq_file *m, void *v) +{ + int i = *(loff_t *)v; + struct tty_ldisc_ops *ldops; + + ldops = get_ldops(i); + if (IS_ERR(ldops)) + return 0; + seq_printf(m, "%-10s %2d\n", ldops->name ? ldops->name : "???", i); + put_ldops(ldops); + return 0; +} + +static const struct seq_operations tty_ldiscs_seq_ops = { + .start = tty_ldiscs_seq_start, + .next = tty_ldiscs_seq_next, + .stop = tty_ldiscs_seq_stop, + .show = tty_ldiscs_seq_show, +}; + +static int proc_tty_ldiscs_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &tty_ldiscs_seq_ops); +} + +const struct file_operations tty_ldiscs_proc_fops = { + .owner = THIS_MODULE, + .open = proc_tty_ldiscs_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +/** + * tty_ldisc_assign - set ldisc on a tty + * @tty: tty to assign + * @ld: line discipline + * + * Install an instance of a line discipline into a tty structure. The + * ldisc must have a reference count above zero to ensure it remains. + * The tty instance refcount starts at zero. + * + * Locking: + * Caller must hold references + */ + +static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) +{ + tty->ldisc = ld; +} + +/** + * tty_ldisc_try - internal helper + * @tty: the tty + * + * Make a single attempt to grab and bump the refcount on + * the tty ldisc. Return 0 on failure or 1 on success. This is + * used to implement both the waiting and non waiting versions + * of tty_ldisc_ref + * + * Locking: takes tty_ldisc_lock + */ + +static struct tty_ldisc *tty_ldisc_try(struct tty_struct *tty) +{ + unsigned long flags; + struct tty_ldisc *ld; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ld = NULL; + if (test_bit(TTY_LDISC, &tty->flags)) + ld = get_ldisc(tty->ldisc); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ld; +} + +/** + * tty_ldisc_ref_wait - wait for the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * wait patiently until it changes. + * + * Note: Must not be called from an IRQ/timer context. The caller + * must also be careful not to hold other locks that will deadlock + * against a discipline change, such as an existing ldisc reference + * (which we check for) + * + * Locking: call functions take tty_ldisc_lock + */ + +struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) +{ + struct tty_ldisc *ld; + + /* wait_event is a macro */ + wait_event(tty_ldisc_wait, (ld = tty_ldisc_try(tty)) != NULL); + return ld; +} +EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); + +/** + * tty_ldisc_ref - get the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * return NULL. Can be called from IRQ and timer functions. + * + * Locking: called functions take tty_ldisc_lock + */ + +struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) +{ + return tty_ldisc_try(tty); +} +EXPORT_SYMBOL_GPL(tty_ldisc_ref); + +/** + * tty_ldisc_deref - free a tty ldisc reference + * @ld: reference to free up + * + * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May + * be called in IRQ context. + * + * Locking: takes tty_ldisc_lock + */ + +void tty_ldisc_deref(struct tty_ldisc *ld) +{ + put_ldisc(ld); +} +EXPORT_SYMBOL_GPL(tty_ldisc_deref); + +static inline void tty_ldisc_put(struct tty_ldisc *ld) +{ + put_ldisc(ld); +} + +/** + * tty_ldisc_enable - allow ldisc use + * @tty: terminal to activate ldisc on + * + * Set the TTY_LDISC flag when the line discipline can be called + * again. Do necessary wakeups for existing sleepers. Clear the LDISC + * changing flag to indicate any ldisc change is now over. + * + * Note: nobody should set the TTY_LDISC bit except via this function. + * Clearing directly is allowed. + */ + +void tty_ldisc_enable(struct tty_struct *tty) +{ + set_bit(TTY_LDISC, &tty->flags); + clear_bit(TTY_LDISC_CHANGING, &tty->flags); + wake_up(&tty_ldisc_wait); +} + +/** + * tty_ldisc_flush - flush line discipline queue + * @tty: tty + * + * Flush the line discipline queue (if any) for this tty. If there + * is no line discipline active this is a no-op. + */ + +void tty_ldisc_flush(struct tty_struct *tty) +{ + struct tty_ldisc *ld = tty_ldisc_ref(tty); + if (ld) { + if (ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_ldisc_deref(ld); + } + tty_buffer_flush(tty); +} +EXPORT_SYMBOL_GPL(tty_ldisc_flush); + +/** + * tty_set_termios_ldisc - set ldisc field + * @tty: tty structure + * @num: line discipline number + * + * This is probably overkill for real world processors but + * they are not on hot paths so a little discipline won't do + * any harm. + * + * Locking: takes termios_mutex + */ + +static void tty_set_termios_ldisc(struct tty_struct *tty, int num) +{ + mutex_lock(&tty->termios_mutex); + tty->termios->c_line = num; + mutex_unlock(&tty->termios_mutex); +} + +/** + * tty_ldisc_open - open a line discipline + * @tty: tty we are opening the ldisc on + * @ld: discipline to open + * + * A helper opening method. Also a convenient debugging and check + * point. + * + * Locking: always called with BTM already held. + */ + +static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) +{ + WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags)); + if (ld->ops->open) { + int ret; + /* BTM here locks versus a hangup event */ + WARN_ON(!tty_locked()); + ret = ld->ops->open(tty); + return ret; + } + return 0; +} + +/** + * tty_ldisc_close - close a line discipline + * @tty: tty we are opening the ldisc on + * @ld: discipline to close + * + * A helper close method. Also a convenient debugging and check + * point. + */ + +static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld) +{ + WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags)); + clear_bit(TTY_LDISC_OPEN, &tty->flags); + if (ld->ops->close) + ld->ops->close(tty); +} + +/** + * tty_ldisc_restore - helper for tty ldisc change + * @tty: tty to recover + * @old: previous ldisc + * + * Restore the previous line discipline or N_TTY when a line discipline + * change fails due to an open error + */ + +static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old) +{ + char buf[64]; + struct tty_ldisc *new_ldisc; + int r; + + /* There is an outstanding reference here so this is safe */ + old = tty_ldisc_get(old->ops->num); + WARN_ON(IS_ERR(old)); + tty_ldisc_assign(tty, old); + tty_set_termios_ldisc(tty, old->ops->num); + if (tty_ldisc_open(tty, old) < 0) { + tty_ldisc_put(old); + /* This driver is always present */ + new_ldisc = tty_ldisc_get(N_TTY); + if (IS_ERR(new_ldisc)) + panic("n_tty: get"); + tty_ldisc_assign(tty, new_ldisc); + tty_set_termios_ldisc(tty, N_TTY); + r = tty_ldisc_open(tty, new_ldisc); + if (r < 0) + panic("Couldn't open N_TTY ldisc for " + "%s --- error %d.", + tty_name(tty, buf), r); + } +} + +/** + * tty_ldisc_halt - shut down the line discipline + * @tty: tty device + * + * Shut down the line discipline and work queue for this tty device. + * The TTY_LDISC flag being cleared ensures no further references can + * be obtained while the delayed work queue halt ensures that no more + * data is fed to the ldisc. + * + * You need to do a 'flush_scheduled_work()' (outside the ldisc_mutex) + * in order to make sure any currently executing ldisc work is also + * flushed. + */ + +static int tty_ldisc_halt(struct tty_struct *tty) +{ + clear_bit(TTY_LDISC, &tty->flags); + return cancel_delayed_work_sync(&tty->buf.work); +} + +/** + * tty_set_ldisc - set line discipline + * @tty: the terminal to set + * @ldisc: the line discipline + * + * Set the discipline of a tty line. Must be called from a process + * context. The ldisc change logic has to protect itself against any + * overlapping ldisc change (including on the other end of pty pairs), + * the close of one side of a tty/pty pair, and eventually hangup. + * + * Locking: takes tty_ldisc_lock, termios_mutex + */ + +int tty_set_ldisc(struct tty_struct *tty, int ldisc) +{ + int retval; + struct tty_ldisc *o_ldisc, *new_ldisc; + int work, o_work = 0; + struct tty_struct *o_tty; + + new_ldisc = tty_ldisc_get(ldisc); + if (IS_ERR(new_ldisc)) + return PTR_ERR(new_ldisc); + + tty_lock(); + /* + * We need to look at the tty locking here for pty/tty pairs + * when both sides try to change in parallel. + */ + + o_tty = tty->link; /* o_tty is the pty side or NULL */ + + + /* + * Check the no-op case + */ + + if (tty->ldisc->ops->num == ldisc) { + tty_unlock(); + tty_ldisc_put(new_ldisc); + return 0; + } + + tty_unlock(); + /* + * Problem: What do we do if this blocks ? + * We could deadlock here + */ + + tty_wait_until_sent(tty, 0); + + tty_lock(); + mutex_lock(&tty->ldisc_mutex); + + /* + * We could be midstream of another ldisc change which has + * dropped the lock during processing. If so we need to wait. + */ + + while (test_bit(TTY_LDISC_CHANGING, &tty->flags)) { + mutex_unlock(&tty->ldisc_mutex); + tty_unlock(); + wait_event(tty_ldisc_wait, + test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0); + tty_lock(); + mutex_lock(&tty->ldisc_mutex); + } + + set_bit(TTY_LDISC_CHANGING, &tty->flags); + + /* + * No more input please, we are switching. The new ldisc + * will update this value in the ldisc open function + */ + + tty->receive_room = 0; + + o_ldisc = tty->ldisc; + + tty_unlock(); + /* + * Make sure we don't change while someone holds a + * reference to the line discipline. The TTY_LDISC bit + * prevents anyone taking a reference once it is clear. + * We need the lock to avoid racing reference takers. + * + * We must clear the TTY_LDISC bit here to avoid a livelock + * with a userspace app continually trying to use the tty in + * parallel to the change and re-referencing the tty. + */ + + work = tty_ldisc_halt(tty); + if (o_tty) + o_work = tty_ldisc_halt(o_tty); + + /* + * Wait for ->hangup_work and ->buf.work handlers to terminate. + * We must drop the mutex here in case a hangup is also in process. + */ + + mutex_unlock(&tty->ldisc_mutex); + + flush_scheduled_work(); + + tty_lock(); + mutex_lock(&tty->ldisc_mutex); + if (test_bit(TTY_HUPPED, &tty->flags)) { + /* We were raced by the hangup method. It will have stomped + the ldisc data and closed the ldisc down */ + clear_bit(TTY_LDISC_CHANGING, &tty->flags); + mutex_unlock(&tty->ldisc_mutex); + tty_ldisc_put(new_ldisc); + tty_unlock(); + return -EIO; + } + + /* Shutdown the current discipline. */ + tty_ldisc_close(tty, o_ldisc); + + /* Now set up the new line discipline. */ + tty_ldisc_assign(tty, new_ldisc); + tty_set_termios_ldisc(tty, ldisc); + + retval = tty_ldisc_open(tty, new_ldisc); + if (retval < 0) { + /* Back to the old one or N_TTY if we can't */ + tty_ldisc_put(new_ldisc); + tty_ldisc_restore(tty, o_ldisc); + } + + /* At this point we hold a reference to the new ldisc and a + a reference to the old ldisc. If we ended up flipping back + to the existing ldisc we have two references to it */ + + if (tty->ldisc->ops->num != o_ldisc->ops->num && tty->ops->set_ldisc) + tty->ops->set_ldisc(tty); + + tty_ldisc_put(o_ldisc); + + /* + * Allow ldisc referencing to occur again + */ + + tty_ldisc_enable(tty); + if (o_tty) + tty_ldisc_enable(o_tty); + + /* Restart the work queue in case no characters kick it off. Safe if + already running */ + if (work) + schedule_delayed_work(&tty->buf.work, 1); + if (o_work) + schedule_delayed_work(&o_tty->buf.work, 1); + mutex_unlock(&tty->ldisc_mutex); + tty_unlock(); + return retval; +} + +/** + * tty_reset_termios - reset terminal state + * @tty: tty to reset + * + * Restore a terminal to the driver default state. + */ + +static void tty_reset_termios(struct tty_struct *tty) +{ + mutex_lock(&tty->termios_mutex); + *tty->termios = tty->driver->init_termios; + tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); + tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); + mutex_unlock(&tty->termios_mutex); +} + + +/** + * tty_ldisc_reinit - reinitialise the tty ldisc + * @tty: tty to reinit + * @ldisc: line discipline to reinitialize + * + * Switch the tty to a line discipline and leave the ldisc + * state closed + */ + +static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc) +{ + struct tty_ldisc *ld; + + tty_ldisc_close(tty, tty->ldisc); + tty_ldisc_put(tty->ldisc); + tty->ldisc = NULL; + /* + * Switch the line discipline back + */ + ld = tty_ldisc_get(ldisc); + BUG_ON(IS_ERR(ld)); + tty_ldisc_assign(tty, ld); + tty_set_termios_ldisc(tty, ldisc); +} + +/** + * tty_ldisc_hangup - hangup ldisc reset + * @tty: tty being hung up + * + * Some tty devices reset their termios when they receive a hangup + * event. In that situation we must also switch back to N_TTY properly + * before we reset the termios data. + * + * Locking: We can take the ldisc mutex as the rest of the code is + * careful to allow for this. + * + * In the pty pair case this occurs in the close() path of the + * tty itself so we must be careful about locking rules. + */ + +void tty_ldisc_hangup(struct tty_struct *tty) +{ + struct tty_ldisc *ld; + int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS; + int err = 0; + + /* + * FIXME! What are the locking issues here? This may me overdoing + * things... This question is especially important now that we've + * removed the irqlock. + */ + ld = tty_ldisc_ref(tty); + if (ld != NULL) { + /* We may have no line discipline at this point */ + if (ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + tty_driver_flush_buffer(tty); + if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && + ld->ops->write_wakeup) + ld->ops->write_wakeup(tty); + if (ld->ops->hangup) + ld->ops->hangup(tty); + tty_ldisc_deref(ld); + } + /* + * FIXME: Once we trust the LDISC code better we can wait here for + * ldisc completion and fix the driver call race + */ + wake_up_interruptible_poll(&tty->write_wait, POLLOUT); + wake_up_interruptible_poll(&tty->read_wait, POLLIN); + /* + * Shutdown the current line discipline, and reset it to + * N_TTY if need be. + * + * Avoid racing set_ldisc or tty_ldisc_release + */ + mutex_lock(&tty->ldisc_mutex); + + /* + * this is like tty_ldisc_halt, but we need to give up + * the BTM before calling cancel_delayed_work_sync, + * which may need to wait for another function taking the BTM + */ + clear_bit(TTY_LDISC, &tty->flags); + tty_unlock(); + cancel_delayed_work_sync(&tty->buf.work); + mutex_unlock(&tty->ldisc_mutex); + + tty_lock(); + mutex_lock(&tty->ldisc_mutex); + + /* At this point we have a closed ldisc and we want to + reopen it. We could defer this to the next open but + it means auditing a lot of other paths so this is + a FIXME */ + if (tty->ldisc) { /* Not yet closed */ + if (reset == 0) { + tty_ldisc_reinit(tty, tty->termios->c_line); + err = tty_ldisc_open(tty, tty->ldisc); + } + /* If the re-open fails or we reset then go to N_TTY. The + N_TTY open cannot fail */ + if (reset || err) { + tty_ldisc_reinit(tty, N_TTY); + WARN_ON(tty_ldisc_open(tty, tty->ldisc)); + } + tty_ldisc_enable(tty); + } + mutex_unlock(&tty->ldisc_mutex); + if (reset) + tty_reset_termios(tty); +} + +/** + * tty_ldisc_setup - open line discipline + * @tty: tty being shut down + * @o_tty: pair tty for pty/tty pairs + * + * Called during the initial open of a tty/pty pair in order to set up the + * line disciplines and bind them to the tty. This has no locking issues + * as the device isn't yet active. + */ + +int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty) +{ + struct tty_ldisc *ld = tty->ldisc; + int retval; + + retval = tty_ldisc_open(tty, ld); + if (retval) + return retval; + + if (o_tty) { + retval = tty_ldisc_open(o_tty, o_tty->ldisc); + if (retval) { + tty_ldisc_close(tty, ld); + return retval; + } + tty_ldisc_enable(o_tty); + } + tty_ldisc_enable(tty); + return 0; +} +/** + * tty_ldisc_release - release line discipline + * @tty: tty being shut down + * @o_tty: pair tty for pty/tty pairs + * + * Called during the final close of a tty/pty pair in order to shut down + * the line discpline layer. On exit the ldisc assigned is N_TTY and the + * ldisc has not been opened. + */ + +void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) +{ + /* + * Prevent flush_to_ldisc() from rescheduling the work for later. Then + * kill any delayed work. As this is the final close it does not + * race with the set_ldisc code path. + */ + + tty_unlock(); + tty_ldisc_halt(tty); + flush_scheduled_work(); + tty_lock(); + + mutex_lock(&tty->ldisc_mutex); + /* + * Now kill off the ldisc + */ + tty_ldisc_close(tty, tty->ldisc); + tty_ldisc_put(tty->ldisc); + /* Force an oops if we mess this up */ + tty->ldisc = NULL; + + /* Ensure the next open requests the N_TTY ldisc */ + tty_set_termios_ldisc(tty, N_TTY); + mutex_unlock(&tty->ldisc_mutex); + + /* This will need doing differently if we need to lock */ + if (o_tty) + tty_ldisc_release(o_tty, NULL); + + /* And the memory resources remaining (buffers, termios) will be + disposed of when the kref hits zero */ +} + +/** + * tty_ldisc_init - ldisc setup for new tty + * @tty: tty being allocated + * + * Set up the line discipline objects for a newly allocated tty. Note that + * the tty structure is not completely set up when this call is made. + */ + +void tty_ldisc_init(struct tty_struct *tty) +{ + struct tty_ldisc *ld = tty_ldisc_get(N_TTY); + if (IS_ERR(ld)) + panic("n_tty: init_tty"); + tty_ldisc_assign(tty, ld); +} + +void tty_ldisc_begin(void) +{ + /* Setup the default TTY line discipline. */ + (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); +} diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c new file mode 100644 index 00000000000..133697540c7 --- /dev/null +++ b/drivers/tty/tty_mutex.c @@ -0,0 +1,47 @@ +/* + * drivers/char/tty_lock.c + */ +#include <linux/tty.h> +#include <linux/module.h> +#include <linux/kallsyms.h> +#include <linux/semaphore.h> +#include <linux/sched.h> + +/* + * The 'big tty mutex' + * + * This mutex is taken and released by tty_lock() and tty_unlock(), + * replacing the older big kernel lock. + * It can no longer be taken recursively, and does not get + * released implicitly while sleeping. + * + * Don't use in new code. + */ +static DEFINE_MUTEX(big_tty_mutex); +struct task_struct *__big_tty_mutex_owner; +EXPORT_SYMBOL_GPL(__big_tty_mutex_owner); + +/* + * Getting the big tty mutex. + */ +void __lockfunc tty_lock(void) +{ + struct task_struct *task = current; + + WARN_ON(__big_tty_mutex_owner == task); + + mutex_lock(&big_tty_mutex); + __big_tty_mutex_owner = task; +} +EXPORT_SYMBOL(tty_lock); + +void __lockfunc tty_unlock(void) +{ + struct task_struct *task = current; + + WARN_ON(__big_tty_mutex_owner != task); + __big_tty_mutex_owner = NULL; + + mutex_unlock(&big_tty_mutex); +} +EXPORT_SYMBOL(tty_unlock); diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c new file mode 100644 index 00000000000..33d37d230f8 --- /dev/null +++ b/drivers/tty/tty_port.c @@ -0,0 +1,446 @@ +/* + * Tty port functions + */ + +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <linux/serial.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/module.h> + +void tty_port_init(struct tty_port *port) +{ + memset(port, 0, sizeof(*port)); + init_waitqueue_head(&port->open_wait); + init_waitqueue_head(&port->close_wait); + init_waitqueue_head(&port->delta_msr_wait); + mutex_init(&port->mutex); + mutex_init(&port->buf_mutex); + spin_lock_init(&port->lock); + port->close_delay = (50 * HZ) / 100; + port->closing_wait = (3000 * HZ) / 100; + kref_init(&port->kref); +} +EXPORT_SYMBOL(tty_port_init); + +int tty_port_alloc_xmit_buf(struct tty_port *port) +{ + /* We may sleep in get_zeroed_page() */ + mutex_lock(&port->buf_mutex); + if (port->xmit_buf == NULL) + port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL); + mutex_unlock(&port->buf_mutex); + if (port->xmit_buf == NULL) + return -ENOMEM; + return 0; +} +EXPORT_SYMBOL(tty_port_alloc_xmit_buf); + +void tty_port_free_xmit_buf(struct tty_port *port) +{ + mutex_lock(&port->buf_mutex); + if (port->xmit_buf != NULL) { + free_page((unsigned long)port->xmit_buf); + port->xmit_buf = NULL; + } + mutex_unlock(&port->buf_mutex); +} +EXPORT_SYMBOL(tty_port_free_xmit_buf); + +static void tty_port_destructor(struct kref *kref) +{ + struct tty_port *port = container_of(kref, struct tty_port, kref); + if (port->xmit_buf) + free_page((unsigned long)port->xmit_buf); + if (port->ops->destruct) + port->ops->destruct(port); + else + kfree(port); +} + +void tty_port_put(struct tty_port *port) +{ + if (port) + kref_put(&port->kref, tty_port_destructor); +} +EXPORT_SYMBOL(tty_port_put); + +/** + * tty_port_tty_get - get a tty reference + * @port: tty port + * + * Return a refcount protected tty instance or NULL if the port is not + * associated with a tty (eg due to close or hangup) + */ + +struct tty_struct *tty_port_tty_get(struct tty_port *port) +{ + unsigned long flags; + struct tty_struct *tty; + + spin_lock_irqsave(&port->lock, flags); + tty = tty_kref_get(port->tty); + spin_unlock_irqrestore(&port->lock, flags); + return tty; +} +EXPORT_SYMBOL(tty_port_tty_get); + +/** + * tty_port_tty_set - set the tty of a port + * @port: tty port + * @tty: the tty + * + * Associate the port and tty pair. Manages any internal refcounts. + * Pass NULL to deassociate a port + */ + +void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + if (port->tty) + tty_kref_put(port->tty); + port->tty = tty_kref_get(tty); + spin_unlock_irqrestore(&port->lock, flags); +} +EXPORT_SYMBOL(tty_port_tty_set); + +static void tty_port_shutdown(struct tty_port *port) +{ + mutex_lock(&port->mutex); + if (port->ops->shutdown && !port->console && + test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) + port->ops->shutdown(port); + mutex_unlock(&port->mutex); +} + +/** + * tty_port_hangup - hangup helper + * @port: tty port + * + * Perform port level tty hangup flag and count changes. Drop the tty + * reference. + */ + +void tty_port_hangup(struct tty_port *port) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + port->count = 0; + port->flags &= ~ASYNC_NORMAL_ACTIVE; + if (port->tty) { + set_bit(TTY_IO_ERROR, &port->tty->flags); + tty_kref_put(port->tty); + } + port->tty = NULL; + spin_unlock_irqrestore(&port->lock, flags); + wake_up_interruptible(&port->open_wait); + wake_up_interruptible(&port->delta_msr_wait); + tty_port_shutdown(port); +} +EXPORT_SYMBOL(tty_port_hangup); + +/** + * tty_port_carrier_raised - carrier raised check + * @port: tty port + * + * Wrapper for the carrier detect logic. For the moment this is used + * to hide some internal details. This will eventually become entirely + * internal to the tty port. + */ + +int tty_port_carrier_raised(struct tty_port *port) +{ + if (port->ops->carrier_raised == NULL) + return 1; + return port->ops->carrier_raised(port); +} +EXPORT_SYMBOL(tty_port_carrier_raised); + +/** + * tty_port_raise_dtr_rts - Raise DTR/RTS + * @port: tty port + * + * Wrapper for the DTR/RTS raise logic. For the moment this is used + * to hide some internal details. This will eventually become entirely + * internal to the tty port. + */ + +void tty_port_raise_dtr_rts(struct tty_port *port) +{ + if (port->ops->dtr_rts) + port->ops->dtr_rts(port, 1); +} +EXPORT_SYMBOL(tty_port_raise_dtr_rts); + +/** + * tty_port_lower_dtr_rts - Lower DTR/RTS + * @port: tty port + * + * Wrapper for the DTR/RTS raise logic. For the moment this is used + * to hide some internal details. This will eventually become entirely + * internal to the tty port. + */ + +void tty_port_lower_dtr_rts(struct tty_port *port) +{ + if (port->ops->dtr_rts) + port->ops->dtr_rts(port, 0); +} +EXPORT_SYMBOL(tty_port_lower_dtr_rts); + +/** + * tty_port_block_til_ready - Waiting logic for tty open + * @port: the tty port being opened + * @tty: the tty device being bound + * @filp: the file pointer of the opener + * + * Implement the core POSIX/SuS tty behaviour when opening a tty device. + * Handles: + * - hangup (both before and during) + * - non blocking open + * - rts/dtr/dcd + * - signals + * - port flags and counts + * + * The passed tty_port must implement the carrier_raised method if it can + * do carrier detect and the dtr_rts method if it supports software + * management of these lines. Note that the dtr/rts raise is done each + * iteration as a hangup may have previously dropped them while we wait. + */ + +int tty_port_block_til_ready(struct tty_port *port, + struct tty_struct *tty, struct file *filp) +{ + int do_clocal = 0, retval; + unsigned long flags; + DEFINE_WAIT(wait); + int cd; + + /* block if port is in the process of being closed */ + if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) { + wait_event_interruptible_tty(port->close_wait, + !(port->flags & ASYNC_CLOSING)); + if (port->flags & ASYNC_HUP_NOTIFY) + return -EAGAIN; + else + return -ERESTARTSYS; + } + + /* if non-blocking mode is set we can pass directly to open unless + the port has just hung up or is in another error state */ + if (tty->flags & (1 << TTY_IO_ERROR)) { + port->flags |= ASYNC_NORMAL_ACTIVE; + return 0; + } + if (filp->f_flags & O_NONBLOCK) { + /* Indicate we are open */ + if (tty->termios->c_cflag & CBAUD) + tty_port_raise_dtr_rts(port); + port->flags |= ASYNC_NORMAL_ACTIVE; + return 0; + } + + if (C_CLOCAL(tty)) + do_clocal = 1; + + /* Block waiting until we can proceed. We may need to wait for the + carrier, but we must also wait for any close that is in progress + before the next open may complete */ + + retval = 0; + + /* The port lock protects the port counts */ + spin_lock_irqsave(&port->lock, flags); + if (!tty_hung_up_p(filp)) + port->count--; + port->blocked_open++; + spin_unlock_irqrestore(&port->lock, flags); + + while (1) { + /* Indicate we are open */ + if (tty->termios->c_cflag & CBAUD) + tty_port_raise_dtr_rts(port); + + prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE); + /* Check for a hangup or uninitialised port. + Return accordingly */ + if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) { + if (port->flags & ASYNC_HUP_NOTIFY) + retval = -EAGAIN; + else + retval = -ERESTARTSYS; + break; + } + /* Probe the carrier. For devices with no carrier detect this + will always return true */ + cd = tty_port_carrier_raised(port); + if (!(port->flags & ASYNC_CLOSING) && + (do_clocal || cd)) + break; + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + tty_unlock(); + schedule(); + tty_lock(); + } + finish_wait(&port->open_wait, &wait); + + /* Update counts. A parallel hangup will have set count to zero and + we must not mess that up further */ + spin_lock_irqsave(&port->lock, flags); + if (!tty_hung_up_p(filp)) + port->count++; + port->blocked_open--; + if (retval == 0) + port->flags |= ASYNC_NORMAL_ACTIVE; + spin_unlock_irqrestore(&port->lock, flags); + return retval; +} +EXPORT_SYMBOL(tty_port_block_til_ready); + +int tty_port_close_start(struct tty_port *port, + struct tty_struct *tty, struct file *filp) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + if (tty_hung_up_p(filp)) { + spin_unlock_irqrestore(&port->lock, flags); + return 0; + } + + if (tty->count == 1 && port->count != 1) { + printk(KERN_WARNING + "tty_port_close_start: tty->count = 1 port count = %d.\n", + port->count); + port->count = 1; + } + if (--port->count < 0) { + printk(KERN_WARNING "tty_port_close_start: count = %d\n", + port->count); + port->count = 0; + } + + if (port->count) { + spin_unlock_irqrestore(&port->lock, flags); + if (port->ops->drop) + port->ops->drop(port); + return 0; + } + set_bit(ASYNCB_CLOSING, &port->flags); + tty->closing = 1; + spin_unlock_irqrestore(&port->lock, flags); + /* Don't block on a stalled port, just pull the chain */ + if (tty->flow_stopped) + tty_driver_flush_buffer(tty); + if (test_bit(ASYNCB_INITIALIZED, &port->flags) && + port->closing_wait != ASYNC_CLOSING_WAIT_NONE) + tty_wait_until_sent(tty, port->closing_wait); + if (port->drain_delay) { + unsigned int bps = tty_get_baud_rate(tty); + long timeout; + + if (bps > 1200) + timeout = max_t(long, + (HZ * 10 * port->drain_delay) / bps, HZ / 10); + else + timeout = 2 * HZ; + schedule_timeout_interruptible(timeout); + } + /* Flush the ldisc buffering */ + tty_ldisc_flush(tty); + + /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to + hang up the line */ + if (tty->termios->c_cflag & HUPCL) + tty_port_lower_dtr_rts(port); + + /* Don't call port->drop for the last reference. Callers will want + to drop the last active reference in ->shutdown() or the tty + shutdown path */ + return 1; +} +EXPORT_SYMBOL(tty_port_close_start); + +void tty_port_close_end(struct tty_port *port, struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + tty->closing = 0; + + if (port->blocked_open) { + spin_unlock_irqrestore(&port->lock, flags); + if (port->close_delay) { + msleep_interruptible( + jiffies_to_msecs(port->close_delay)); + } + spin_lock_irqsave(&port->lock, flags); + wake_up_interruptible(&port->open_wait); + } + port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING); + wake_up_interruptible(&port->close_wait); + spin_unlock_irqrestore(&port->lock, flags); +} +EXPORT_SYMBOL(tty_port_close_end); + +void tty_port_close(struct tty_port *port, struct tty_struct *tty, + struct file *filp) +{ + if (tty_port_close_start(port, tty, filp) == 0) + return; + tty_port_shutdown(port); + set_bit(TTY_IO_ERROR, &tty->flags); + tty_port_close_end(port, tty); + tty_port_tty_set(port, NULL); +} +EXPORT_SYMBOL(tty_port_close); + +int tty_port_open(struct tty_port *port, struct tty_struct *tty, + struct file *filp) +{ + spin_lock_irq(&port->lock); + if (!tty_hung_up_p(filp)) + ++port->count; + spin_unlock_irq(&port->lock); + tty_port_tty_set(port, tty); + + /* + * Do the device-specific open only if the hardware isn't + * already initialized. Serialize open and shutdown using the + * port mutex. + */ + + mutex_lock(&port->mutex); + + if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) { + clear_bit(TTY_IO_ERROR, &tty->flags); + if (port->ops->activate) { + int retval = port->ops->activate(port, tty); + if (retval) { + mutex_unlock(&port->mutex); + return retval; + } + } + set_bit(ASYNCB_INITIALIZED, &port->flags); + } + mutex_unlock(&port->mutex); + return tty_port_block_til_ready(port, tty, filp); +} + +EXPORT_SYMBOL(tty_port_open); |