diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r-- | drivers/tty/tty_io.c | 375 |
1 files changed, 250 insertions, 125 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b425c79675a..8a5a8b06461 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -181,10 +181,13 @@ struct tty_struct *alloc_tty_struct(void) void free_tty_struct(struct tty_struct *tty) { + if (!tty) + return; if (tty->dev) put_device(tty->dev); kfree(tty->write_buf); tty_buffer_free_all(tty); + tty->magic = 0xDEADDEAD; kfree(tty); } @@ -573,7 +576,7 @@ void __tty_hangup(struct tty_struct *tty) } spin_unlock(&redirect_lock); - tty_lock(); + tty_lock(tty); /* some functions below drop BTM, so we need this bit */ set_bit(TTY_HUPPING, &tty->flags); @@ -666,7 +669,7 @@ void __tty_hangup(struct tty_struct *tty) clear_bit(TTY_HUPPING, &tty->flags); tty_ldisc_enable(tty); - tty_unlock(); + tty_unlock(tty); if (f) fput(f); @@ -1103,12 +1106,12 @@ void tty_write_message(struct tty_struct *tty, char *msg) { if (tty) { mutex_lock(&tty->atomic_write_lock); - tty_lock(); + tty_lock(tty); if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) { - tty_unlock(); + tty_unlock(tty); tty->ops->write(tty, msg, strlen(msg)); } else - tty_unlock(); + tty_unlock(tty); tty_write_unlock(tty); } return; @@ -1213,7 +1216,10 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p) */ static void tty_line_name(struct tty_driver *driver, int index, char *p) { - sprintf(p, "%s%d", driver->name, index + driver->name_base); + if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) + strcpy(p, driver->name); + else + sprintf(p, "%s%d", driver->name, index + driver->name_base); } /** @@ -1249,21 +1255,19 @@ 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; + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + tty->termios = tty->driver->init_termios; + else { + /* Check for lazy saved data */ + tp = tty->driver->termios[idx]; + if (tp != NULL) + tty->termios = *tp; + else + tty->termios = tty->driver->init_termios; } - 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); + 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); @@ -1403,10 +1407,18 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) } initialize_tty_struct(tty, driver, idx); + tty_lock(tty); retval = tty_driver_install_tty(driver, tty); if (retval < 0) goto err_deinit_tty; + if (!tty->port) + tty->port = driver->ports[idx]; + + WARN_RATELIMIT(!tty->port, + "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n", + __func__, tty->driver->name); + /* * Structures all installed ... call the ldisc open routines. * If we fail here just call release_tty to clean up. No need @@ -1415,9 +1427,11 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) retval = tty_ldisc_setup(tty, tty->link); if (retval) goto err_release_tty; + /* Return the tty locked so that it cannot vanish under the caller */ return tty; err_deinit_tty: + tty_unlock(tty); deinitialize_tty_struct(tty); free_tty_struct(tty); err_module_put: @@ -1426,6 +1440,7 @@ err_module_put: /* call the tty release_tty routine to clean out this slot */ err_release_tty: + tty_unlock(tty); printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, " "clearing slot %d\n", idx); release_tty(tty, idx); @@ -1436,22 +1451,25 @@ 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); + + /* If the port is going to reset then it has no termios to save */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + return; + + /* Stash the termios data */ + tp = tty->driver->termios[idx]; + if (tp == NULL) { + tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); + if (tp == NULL) { + pr_warn("tty: no memory to save termios state.\n"); + return; + } + tty->driver->termios[idx] = tp; } + *tp = tty->termios; } 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 @@ -1462,7 +1480,6 @@ EXPORT_SYMBOL(tty_shutdown); * 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. * @@ -1495,11 +1512,6 @@ 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); @@ -1528,16 +1540,20 @@ EXPORT_SYMBOL(tty_kref_put); * and decrement the refcount of the backing module. * * Locking: - * tty_mutex - sometimes only + * tty_mutex * 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); + WARN_ON(!mutex_is_locked(&tty_mutex)); + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + tty_free_termios(tty); + tty_driver_remove_tty(tty->driver, tty); if (tty->link) tty_kref_put(tty->link); @@ -1572,22 +1588,12 @@ static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty, __func__, idx, tty->name); return -1; } - if (tty->termios != tty->driver->termios[idx]) { - printk(KERN_DEBUG "%s: driver.termios[%d] not termios for (%s)\n", - __func__, idx, tty->name); - return -1; - } if (tty->driver->other) { if (o_tty != tty->driver->other->ttys[idx]) { printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n", __func__, idx, tty->name); return -1; } - if (o_tty->termios != tty->driver->other->termios[idx]) { - printk(KERN_DEBUG "%s: other->termios[%d] not o_termios for (%s)\n", - __func__, idx, tty->name); - return -1; - } if (o_tty->link != tty) { printk(KERN_DEBUG "%s: bad pty pointers\n", __func__); return -1; @@ -1628,7 +1634,7 @@ int tty_release(struct inode *inode, struct file *filp) if (tty_paranoia_check(tty, inode, __func__)) return 0; - tty_lock(); + tty_lock(tty); check_tty_count(tty, __func__); __tty_fasync(-1, filp, 0); @@ -1637,10 +1643,11 @@ int tty_release(struct inode *inode, struct file *filp) pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER); devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; + /* Review: parallel close */ o_tty = tty->link; if (tty_release_checks(tty, o_tty, idx)) { - tty_unlock(); + tty_unlock(tty); return 0; } @@ -1652,7 +1659,7 @@ int tty_release(struct inode *inode, struct file *filp) if (tty->ops->close) tty->ops->close(tty, filp); - tty_unlock(); + tty_unlock(tty); /* * 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 @@ -1675,7 +1682,7 @@ int tty_release(struct inode *inode, struct file *filp) opens on /dev/tty */ mutex_lock(&tty_mutex); - tty_lock(); + tty_lock_pair(tty, o_tty); tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); @@ -1706,7 +1713,7 @@ int tty_release(struct inode *inode, struct file *filp) printk(KERN_WARNING "%s: %s: read/write wait queue active!\n", __func__, tty_name(tty, buf)); - tty_unlock(); + tty_unlock_pair(tty, o_tty); mutex_unlock(&tty_mutex); schedule(); } @@ -1715,6 +1722,9 @@ int tty_release(struct inode *inode, struct file *filp) * 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. + * + * We must *not* drop the tty_mutex until we ensure that a further + * entry into tty_open can not pick up this tty. */ if (pty_master) { if (--o_tty->count < 0) { @@ -1766,12 +1776,13 @@ int tty_release(struct inode *inode, struct file *filp) } mutex_unlock(&tty_mutex); + tty_unlock_pair(tty, o_tty); + /* At this point the TTY_CLOSING flag should ensure a dead tty + cannot be re-opened by a racing opener */ /* check whether both sides are closing ... */ - if (!tty_closing || (o_tty && !o_tty_closing)) { - tty_unlock(); + if (!tty_closing || (o_tty && !o_tty_closing)) return 0; - } #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__); @@ -1782,14 +1793,17 @@ int tty_release(struct inode *inode, struct file *filp) tty_ldisc_release(tty, o_tty); /* * The release_tty function takes care of the details of clearing - * the slots and preserving the termios structure. + * the slots and preserving the termios structure. The tty_unlock_pair + * should be safe as we keep a kref while the tty is locked (so the + * unlock never unlocks a freed tty). */ + mutex_lock(&tty_mutex); release_tty(tty, idx); + mutex_unlock(&tty_mutex); /* Make this pty number available for reallocation */ if (devpts) devpts_kill_index(inode, idx); - tty_unlock(); return 0; } @@ -1893,6 +1907,9 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev. * tty->count should protect the rest. * ->siglock protects ->signal/->sighand + * + * Note: the tty_unlock/lock cases without a ref are only safe due to + * tty_mutex */ static int tty_open(struct inode *inode, struct file *filp) @@ -1916,8 +1933,7 @@ retry_open: retval = 0; mutex_lock(&tty_mutex); - tty_lock(); - + /* This is protected by the tty_mutex */ tty = tty_open_current_tty(device, filp); if (IS_ERR(tty)) { retval = PTR_ERR(tty); @@ -1938,17 +1954,19 @@ retry_open: } if (tty) { + tty_lock(tty); retval = tty_reopen(tty); - if (retval) + if (retval < 0) { + tty_unlock(tty); tty = ERR_PTR(retval); - } else + } + } else /* Returns with the tty_lock held for now */ tty = tty_init_dev(driver, index); mutex_unlock(&tty_mutex); if (driver) tty_driver_kref_put(driver); if (IS_ERR(tty)) { - tty_unlock(); retval = PTR_ERR(tty); goto err_file; } @@ -1977,7 +1995,7 @@ retry_open: printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__, retval, tty->name); #endif - tty_unlock(); /* need to call tty_release without BTM */ + tty_unlock(tty); /* need to call tty_release without BTM */ tty_release(inode, filp); if (retval != -ERESTARTSYS) return retval; @@ -1989,17 +2007,15 @@ retry_open: /* * 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(); + tty_unlock(tty); mutex_lock(&tty_mutex); - tty_lock(); + tty_lock(tty); spin_lock_irq(¤t->sighand->siglock); if (!noctty && current->signal->leader && @@ -2007,11 +2023,10 @@ retry_open: tty->session == NULL) __proc_set_tty(current, tty); spin_unlock_irq(¤t->sighand->siglock); - tty_unlock(); + tty_unlock(tty); mutex_unlock(&tty_mutex); return 0; err_unlock: - tty_unlock(); mutex_unlock(&tty_mutex); /* after locks to avoid deadlock */ if (!IS_ERR_OR_NULL(driver)) @@ -2094,10 +2109,13 @@ out: static int tty_fasync(int fd, struct file *filp, int on) { + struct tty_struct *tty = file_tty(filp); int retval; - tty_lock(); + + tty_lock(tty); retval = __tty_fasync(fd, filp, on); - tty_unlock(); + tty_unlock(tty); + return retval; } @@ -2756,7 +2774,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (ld->ops->ioctl) { retval = ld->ops->ioctl(tty, file, cmd, arg); if (retval == -ENOIOCTLCMD) - retval = -EINVAL; + retval = -ENOTTY; } tty_ldisc_deref(ld); return retval; @@ -2934,6 +2952,7 @@ void initialize_tty_struct(struct tty_struct *tty, tty->pgrp = NULL; tty->overrun_time = jiffies; tty_buffer_init(tty); + mutex_init(&tty->legacy_mutex); mutex_init(&tty->termios_mutex); mutex_init(&tty->ldisc_mutex); init_waitqueue_head(&tty->write_wait); @@ -2991,6 +3010,15 @@ EXPORT_SYMBOL_GPL(tty_put_char); struct class *tty_class; +static int tty_cdev_add(struct tty_driver *driver, dev_t dev, + unsigned int index, unsigned int count) +{ + /* init here, since reused cdevs cause crashes */ + cdev_init(&driver->cdevs[index], &tty_fops); + driver->cdevs[index].owner = driver->owner; + return cdev_add(&driver->cdevs[index], dev, count); +} + /** * tty_register_device - register a tty device * @driver: the tty driver that describes the tty device @@ -3013,8 +3041,46 @@ struct class *tty_class; struct device *tty_register_device(struct tty_driver *driver, unsigned index, struct device *device) { + return tty_register_device_attr(driver, index, device, NULL, NULL); +} +EXPORT_SYMBOL(tty_register_device); + +static void tty_device_create_release(struct device *dev) +{ + pr_debug("device: '%s': %s\n", dev_name(dev), __func__); + kfree(dev); +} + +/** + * tty_register_device_attr - 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. + * @drvdata: Driver data to be set to device. + * @attr_grp: Attribute group to be set on device. + * + * 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_attr(struct tty_driver *driver, + unsigned index, struct device *device, + void *drvdata, + const struct attribute_group **attr_grp) +{ char name[64]; - dev_t dev = MKDEV(driver->major, driver->minor_start) + index; + dev_t devt = MKDEV(driver->major, driver->minor_start) + index; + struct device *dev = NULL; + int retval = -ENODEV; + bool cdev = false; if (index >= driver->num) { printk(KERN_ERR "Attempt to register invalid tty line number " @@ -3027,9 +3093,40 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index, else tty_line_name(driver, index, name); - return device_create(tty_class, device, dev, NULL, name); + if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { + retval = tty_cdev_add(driver, devt, index, 1); + if (retval) + goto error; + cdev = true; + } + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + retval = -ENOMEM; + goto error; + } + + dev->devt = devt; + dev->class = tty_class; + dev->parent = device; + dev->release = tty_device_create_release; + dev_set_name(dev, "%s", name); + dev->groups = attr_grp; + dev_set_drvdata(dev, drvdata); + + retval = device_register(dev); + if (retval) + goto error; + + return dev; + +error: + put_device(dev); + if (cdev) + cdev_del(&driver->cdevs[index]); + return ERR_PTR(retval); } -EXPORT_SYMBOL(tty_register_device); +EXPORT_SYMBOL_GPL(tty_register_device_attr); /** * tty_unregister_device - unregister a tty device @@ -3046,31 +3143,82 @@ void tty_unregister_device(struct tty_driver *driver, unsigned index) { device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); + if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) + cdev_del(&driver->cdevs[index]); } EXPORT_SYMBOL(tty_unregister_device); -struct tty_driver *__alloc_tty_driver(int lines, struct module *owner) +/** + * __tty_alloc_driver -- allocate tty driver + * @lines: count of lines this driver can handle at most + * @owner: module which is repsonsible for this driver + * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags + * + * This should not be called directly, some of the provided macros should be + * used instead. Use IS_ERR and friends on @retval. + */ +struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, + unsigned long flags) { struct tty_driver *driver; + unsigned int cdevs = 1; + int err; + + if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) + return ERR_PTR(-EINVAL); driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); - if (driver) { - kref_init(&driver->kref); - driver->magic = TTY_DRIVER_MAGIC; - driver->num = lines; - driver->owner = owner; - /* later we'll move allocation of tables here */ + if (!driver) + return ERR_PTR(-ENOMEM); + + kref_init(&driver->kref); + driver->magic = TTY_DRIVER_MAGIC; + driver->num = lines; + driver->owner = owner; + driver->flags = flags; + + if (!(flags & TTY_DRIVER_DEVPTS_MEM)) { + driver->ttys = kcalloc(lines, sizeof(*driver->ttys), + GFP_KERNEL); + driver->termios = kcalloc(lines, sizeof(*driver->termios), + GFP_KERNEL); + if (!driver->ttys || !driver->termios) { + err = -ENOMEM; + goto err_free_all; + } } + + if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) { + driver->ports = kcalloc(lines, sizeof(*driver->ports), + GFP_KERNEL); + if (!driver->ports) { + err = -ENOMEM; + goto err_free_all; + } + cdevs = lines; + } + + driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL); + if (!driver->cdevs) { + err = -ENOMEM; + goto err_free_all; + } + return driver; +err_free_all: + kfree(driver->ports); + kfree(driver->ttys); + kfree(driver->termios); + kfree(driver); + return ERR_PTR(err); } -EXPORT_SYMBOL(__alloc_tty_driver); +EXPORT_SYMBOL(__tty_alloc_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) { /* @@ -3087,13 +3235,14 @@ static void destruct_tty_driver(struct kref *kref) 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); + if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) + cdev_del(&driver->cdevs[0]); } + kfree(driver->cdevs); + kfree(driver->ports); + kfree(driver->termios); + kfree(driver->ttys); kfree(driver); } @@ -3124,15 +3273,8 @@ 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); @@ -3144,28 +3286,13 @@ int tty_register_driver(struct tty_driver *driver) dev = MKDEV(driver->major, driver->minor_start); error = register_chrdev_region(dev, driver->num, driver->name); } - if (error < 0) { - kfree(p); - return error; - } + if (error < 0) + goto err; - 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; + if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) { + error = tty_cdev_add(driver, dev, 0, driver->num); + if (error) + goto err_unreg_char; } mutex_lock(&tty_mutex); @@ -3177,7 +3304,7 @@ int tty_register_driver(struct tty_driver *driver) d = tty_register_device(driver, i, NULL); if (IS_ERR(d)) { error = PTR_ERR(d); - goto err; + goto err_unreg_devs; } } } @@ -3185,7 +3312,7 @@ int tty_register_driver(struct tty_driver *driver) driver->flags |= TTY_DRIVER_INSTALLED; return 0; -err: +err_unreg_devs: for (i--; i >= 0; i--) tty_unregister_device(driver, i); @@ -3193,13 +3320,11 @@ err: list_del(&driver->tty_drivers); mutex_unlock(&tty_mutex); +err_unreg_char: unregister_chrdev_region(dev, driver->num); - driver->ttys = NULL; - driver->termios = NULL; - kfree(p); +err: return error; } - EXPORT_SYMBOL(tty_register_driver); /* |