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-rw-r--r--ipc/mqueue.c1252
1 files changed, 1252 insertions, 0 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
new file mode 100644
index 00000000000..cb0cd3cf3b5
--- /dev/null
+++ b/ipc/mqueue.c
@@ -0,0 +1,1252 @@
+/*
+ * POSIX message queues filesystem for Linux.
+ *
+ * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
+ * Michal Wronski (wrona@mat.uni.torun.pl)
+ *
+ * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
+ * Lockless receive & send, fd based notify:
+ * Manfred Spraul (manfred@colorfullife.com)
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/sysctl.h>
+#include <linux/poll.h>
+#include <linux/mqueue.h>
+#include <linux/msg.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/syscalls.h>
+#include <net/sock.h>
+#include "util.h"
+
+#define MQUEUE_MAGIC 0x19800202
+#define DIRENT_SIZE 20
+#define FILENT_SIZE 80
+
+#define SEND 0
+#define RECV 1
+
+#define STATE_NONE 0
+#define STATE_PENDING 1
+#define STATE_READY 2
+
+/* used by sysctl */
+#define FS_MQUEUE 1
+#define CTL_QUEUESMAX 2
+#define CTL_MSGMAX 3
+#define CTL_MSGSIZEMAX 4
+
+/* default values */
+#define DFLT_QUEUESMAX 256 /* max number of message queues */
+#define DFLT_MSGMAX 10 /* max number of messages in each queue */
+#define HARD_MSGMAX (131072/sizeof(void*))
+#define DFLT_MSGSIZEMAX 8192 /* max message size */
+
+#define NOTIFY_COOKIE_LEN 32
+
+struct ext_wait_queue { /* queue of sleeping tasks */
+ struct task_struct *task;
+ struct list_head list;
+ struct msg_msg *msg; /* ptr of loaded message */
+ int state; /* one of STATE_* values */
+};
+
+struct mqueue_inode_info {
+ spinlock_t lock;
+ struct inode vfs_inode;
+ wait_queue_head_t wait_q;
+
+ struct msg_msg **messages;
+ struct mq_attr attr;
+
+ struct sigevent notify;
+ pid_t notify_owner;
+ struct user_struct *user; /* user who created, for accouting */
+ struct sock *notify_sock;
+ struct sk_buff *notify_cookie;
+
+ /* for tasks waiting for free space and messages, respectively */
+ struct ext_wait_queue e_wait_q[2];
+
+ unsigned long qsize; /* size of queue in memory (sum of all msgs) */
+};
+
+static struct inode_operations mqueue_dir_inode_operations;
+static struct file_operations mqueue_file_operations;
+static struct super_operations mqueue_super_ops;
+static void remove_notification(struct mqueue_inode_info *info);
+
+static spinlock_t mq_lock;
+static kmem_cache_t *mqueue_inode_cachep;
+static struct vfsmount *mqueue_mnt;
+
+static unsigned int queues_count;
+static unsigned int queues_max = DFLT_QUEUESMAX;
+static unsigned int msg_max = DFLT_MSGMAX;
+static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
+
+static struct ctl_table_header * mq_sysctl_table;
+
+static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
+{
+ return container_of(inode, struct mqueue_inode_info, vfs_inode);
+}
+
+static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
+ struct mq_attr *attr)
+{
+ struct inode *inode;
+
+ inode = new_inode(sb);
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_mtime = inode->i_ctime = inode->i_atime =
+ CURRENT_TIME;
+
+ if (S_ISREG(mode)) {
+ struct mqueue_inode_info *info;
+ struct task_struct *p = current;
+ struct user_struct *u = p->user;
+ unsigned long mq_bytes, mq_msg_tblsz;
+
+ inode->i_fop = &mqueue_file_operations;
+ inode->i_size = FILENT_SIZE;
+ /* mqueue specific info */
+ info = MQUEUE_I(inode);
+ spin_lock_init(&info->lock);
+ init_waitqueue_head(&info->wait_q);
+ INIT_LIST_HEAD(&info->e_wait_q[0].list);
+ INIT_LIST_HEAD(&info->e_wait_q[1].list);
+ info->messages = NULL;
+ info->notify_owner = 0;
+ info->qsize = 0;
+ info->user = NULL; /* set when all is ok */
+ memset(&info->attr, 0, sizeof(info->attr));
+ info->attr.mq_maxmsg = DFLT_MSGMAX;
+ info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
+ if (attr) {
+ info->attr.mq_maxmsg = attr->mq_maxmsg;
+ info->attr.mq_msgsize = attr->mq_msgsize;
+ }
+ mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
+ mq_bytes = (mq_msg_tblsz +
+ (info->attr.mq_maxmsg * info->attr.mq_msgsize));
+
+ spin_lock(&mq_lock);
+ if (u->mq_bytes + mq_bytes < u->mq_bytes ||
+ u->mq_bytes + mq_bytes >
+ p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
+ spin_unlock(&mq_lock);
+ goto out_inode;
+ }
+ u->mq_bytes += mq_bytes;
+ spin_unlock(&mq_lock);
+
+ info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
+ if (!info->messages) {
+ spin_lock(&mq_lock);
+ u->mq_bytes -= mq_bytes;
+ spin_unlock(&mq_lock);
+ goto out_inode;
+ }
+ /* all is ok */
+ info->user = get_uid(u);
+ } else if (S_ISDIR(mode)) {
+ inode->i_nlink++;
+ /* Some things misbehave if size == 0 on a directory */
+ inode->i_size = 2 * DIRENT_SIZE;
+ inode->i_op = &mqueue_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ }
+ }
+ return inode;
+out_inode:
+ make_bad_inode(inode);
+ iput(inode);
+ return NULL;
+}
+
+static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *inode;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = MQUEUE_MAGIC;
+ sb->s_op = &mqueue_super_ops;
+
+ inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
+ if (!inode)
+ return -ENOMEM;
+
+ sb->s_root = d_alloc_root(inode);
+ if (!sb->s_root) {
+ iput(inode);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static struct super_block *mqueue_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, mqueue_fill_super);
+}
+
+static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags)
+{
+ struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
+
+ if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR)
+ inode_init_once(&p->vfs_inode);
+}
+
+static struct inode *mqueue_alloc_inode(struct super_block *sb)
+{
+ struct mqueue_inode_info *ei;
+
+ ei = kmem_cache_alloc(mqueue_inode_cachep, SLAB_KERNEL);
+ if (!ei)
+ return NULL;
+ return &ei->vfs_inode;
+}
+
+static void mqueue_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
+}
+
+static void mqueue_delete_inode(struct inode *inode)
+{
+ struct mqueue_inode_info *info;
+ struct user_struct *user;
+ unsigned long mq_bytes;
+ int i;
+
+ if (S_ISDIR(inode->i_mode)) {
+ clear_inode(inode);
+ return;
+ }
+ info = MQUEUE_I(inode);
+ spin_lock(&info->lock);
+ for (i = 0; i < info->attr.mq_curmsgs; i++)
+ free_msg(info->messages[i]);
+ kfree(info->messages);
+ spin_unlock(&info->lock);
+
+ clear_inode(inode);
+
+ mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
+ (info->attr.mq_maxmsg * info->attr.mq_msgsize));
+ user = info->user;
+ if (user) {
+ spin_lock(&mq_lock);
+ user->mq_bytes -= mq_bytes;
+ queues_count--;
+ spin_unlock(&mq_lock);
+ free_uid(user);
+ }
+}
+
+static int mqueue_create(struct inode *dir, struct dentry *dentry,
+ int mode, struct nameidata *nd)
+{
+ struct inode *inode;
+ struct mq_attr *attr = dentry->d_fsdata;
+ int error;
+
+ spin_lock(&mq_lock);
+ if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
+ error = -ENOSPC;
+ goto out_lock;
+ }
+ queues_count++;
+ spin_unlock(&mq_lock);
+
+ inode = mqueue_get_inode(dir->i_sb, mode, attr);
+ if (!inode) {
+ error = -ENOMEM;
+ spin_lock(&mq_lock);
+ queues_count--;
+ goto out_lock;
+ }
+
+ dir->i_size += DIRENT_SIZE;
+ dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
+
+ d_instantiate(dentry, inode);
+ dget(dentry);
+ return 0;
+out_lock:
+ spin_unlock(&mq_lock);
+ return error;
+}
+
+static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
+ dir->i_size -= DIRENT_SIZE;
+ inode->i_nlink--;
+ dput(dentry);
+ return 0;
+}
+
+/*
+* This is routine for system read from queue file.
+* To avoid mess with doing here some sort of mq_receive we allow
+* to read only queue size & notification info (the only values
+* that are interesting from user point of view and aren't accessible
+* through std routines)
+*/
+static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
+ size_t count, loff_t * off)
+{
+ struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
+ char buffer[FILENT_SIZE];
+ size_t slen;
+ loff_t o;
+
+ if (!count)
+ return 0;
+
+ spin_lock(&info->lock);
+ snprintf(buffer, sizeof(buffer),
+ "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
+ info->qsize,
+ info->notify_owner ? info->notify.sigev_notify : 0,
+ (info->notify_owner &&
+ info->notify.sigev_notify == SIGEV_SIGNAL) ?
+ info->notify.sigev_signo : 0,
+ info->notify_owner);
+ spin_unlock(&info->lock);
+ buffer[sizeof(buffer)-1] = '\0';
+ slen = strlen(buffer)+1;
+
+ o = *off;
+ if (o > slen)
+ return 0;
+
+ if (o + count > slen)
+ count = slen - o;
+
+ if (copy_to_user(u_data, buffer + o, count))
+ return -EFAULT;
+
+ *off = o + count;
+ filp->f_dentry->d_inode->i_atime = filp->f_dentry->d_inode->i_ctime = CURRENT_TIME;
+ return count;
+}
+
+static int mqueue_flush_file(struct file *filp)
+{
+ struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
+
+ spin_lock(&info->lock);
+ if (current->tgid == info->notify_owner)
+ remove_notification(info);
+
+ spin_unlock(&info->lock);
+ return 0;
+}
+
+static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
+{
+ struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
+ int retval = 0;
+
+ poll_wait(filp, &info->wait_q, poll_tab);
+
+ spin_lock(&info->lock);
+ if (info->attr.mq_curmsgs)
+ retval = POLLIN | POLLRDNORM;
+
+ if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
+ retval |= POLLOUT | POLLWRNORM;
+ spin_unlock(&info->lock);
+
+ return retval;
+}
+
+/* Adds current to info->e_wait_q[sr] before element with smaller prio */
+static void wq_add(struct mqueue_inode_info *info, int sr,
+ struct ext_wait_queue *ewp)
+{
+ struct ext_wait_queue *walk;
+
+ ewp->task = current;
+
+ list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
+ if (walk->task->static_prio <= current->static_prio) {
+ list_add_tail(&ewp->list, &walk->list);
+ return;
+ }
+ }
+ list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
+}
+
+/*
+ * Puts current task to sleep. Caller must hold queue lock. After return
+ * lock isn't held.
+ * sr: SEND or RECV
+ */
+static int wq_sleep(struct mqueue_inode_info *info, int sr,
+ long timeout, struct ext_wait_queue *ewp)
+{
+ int retval;
+ signed long time;
+
+ wq_add(info, sr, ewp);
+
+ for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ spin_unlock(&info->lock);
+ time = schedule_timeout(timeout);
+
+ while (ewp->state == STATE_PENDING)
+ cpu_relax();
+
+ if (ewp->state == STATE_READY) {
+ retval = 0;
+ goto out;
+ }
+ spin_lock(&info->lock);
+ if (ewp->state == STATE_READY) {
+ retval = 0;
+ goto out_unlock;
+ }
+ if (signal_pending(current)) {
+ retval = -ERESTARTSYS;
+ break;
+ }
+ if (time == 0) {
+ retval = -ETIMEDOUT;
+ break;
+ }
+ }
+ list_del(&ewp->list);
+out_unlock:
+ spin_unlock(&info->lock);
+out:
+ return retval;
+}
+
+/*
+ * Returns waiting task that should be serviced first or NULL if none exists
+ */
+static struct ext_wait_queue *wq_get_first_waiter(
+ struct mqueue_inode_info *info, int sr)
+{
+ struct list_head *ptr;
+
+ ptr = info->e_wait_q[sr].list.prev;
+ if (ptr == &info->e_wait_q[sr].list)
+ return NULL;
+ return list_entry(ptr, struct ext_wait_queue, list);
+}
+
+/* Auxiliary functions to manipulate messages' list */
+static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
+{
+ int k;
+
+ k = info->attr.mq_curmsgs - 1;
+ while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
+ info->messages[k + 1] = info->messages[k];
+ k--;
+ }
+ info->attr.mq_curmsgs++;
+ info->qsize += ptr->m_ts;
+ info->messages[k + 1] = ptr;
+}
+
+static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
+{
+ info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
+ return info->messages[info->attr.mq_curmsgs];
+}
+
+static inline void set_cookie(struct sk_buff *skb, char code)
+{
+ ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
+}
+
+/*
+ * The next function is only to split too long sys_mq_timedsend
+ */
+static void __do_notify(struct mqueue_inode_info *info)
+{
+ /* notification
+ * invoked when there is registered process and there isn't process
+ * waiting synchronously for message AND state of queue changed from
+ * empty to not empty. Here we are sure that no one is waiting
+ * synchronously. */
+ if (info->notify_owner &&
+ info->attr.mq_curmsgs == 1) {
+ struct siginfo sig_i;
+ switch (info->notify.sigev_notify) {
+ case SIGEV_NONE:
+ break;
+ case SIGEV_SIGNAL:
+ /* sends signal */
+
+ sig_i.si_signo = info->notify.sigev_signo;
+ sig_i.si_errno = 0;
+ sig_i.si_code = SI_MESGQ;
+ sig_i.si_value = info->notify.sigev_value;
+ sig_i.si_pid = current->tgid;
+ sig_i.si_uid = current->uid;
+
+ kill_proc_info(info->notify.sigev_signo,
+ &sig_i, info->notify_owner);
+ break;
+ case SIGEV_THREAD:
+ set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
+ netlink_sendskb(info->notify_sock,
+ info->notify_cookie, 0);
+ break;
+ }
+ /* after notification unregisters process */
+ info->notify_owner = 0;
+ }
+ wake_up(&info->wait_q);
+}
+
+static long prepare_timeout(const struct timespec __user *u_arg)
+{
+ struct timespec ts, nowts;
+ long timeout;
+
+ if (u_arg) {
+ if (unlikely(copy_from_user(&ts, u_arg,
+ sizeof(struct timespec))))
+ return -EFAULT;
+
+ if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
+ || ts.tv_nsec >= NSEC_PER_SEC))
+ return -EINVAL;
+ nowts = CURRENT_TIME;
+ /* first subtract as jiffies can't be too big */
+ ts.tv_sec -= nowts.tv_sec;
+ if (ts.tv_nsec < nowts.tv_nsec) {
+ ts.tv_nsec += NSEC_PER_SEC;
+ ts.tv_sec--;
+ }
+ ts.tv_nsec -= nowts.tv_nsec;
+ if (ts.tv_sec < 0)
+ return 0;
+
+ timeout = timespec_to_jiffies(&ts) + 1;
+ } else
+ return MAX_SCHEDULE_TIMEOUT;
+
+ return timeout;
+}
+
+static void remove_notification(struct mqueue_inode_info *info)
+{
+ if (info->notify_owner != 0 &&
+ info->notify.sigev_notify == SIGEV_THREAD) {
+ set_cookie(info->notify_cookie, NOTIFY_REMOVED);
+ netlink_sendskb(info->notify_sock, info->notify_cookie, 0);
+ }
+ info->notify_owner = 0;
+}
+
+static int mq_attr_ok(struct mq_attr *attr)
+{
+ if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
+ return 0;
+ if (capable(CAP_SYS_RESOURCE)) {
+ if (attr->mq_maxmsg > HARD_MSGMAX)
+ return 0;
+ } else {
+ if (attr->mq_maxmsg > msg_max ||
+ attr->mq_msgsize > msgsize_max)
+ return 0;
+ }
+ /* check for overflow */
+ if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
+ return 0;
+ if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
+ (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
+ (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
+ return 0;
+ return 1;
+}
+
+/*
+ * Invoked when creating a new queue via sys_mq_open
+ */
+static struct file *do_create(struct dentry *dir, struct dentry *dentry,
+ int oflag, mode_t mode, struct mq_attr __user *u_attr)
+{
+ struct file *filp;
+ struct mq_attr attr;
+ int ret;
+
+ if (u_attr != NULL) {
+ if (copy_from_user(&attr, u_attr, sizeof(attr)))
+ return ERR_PTR(-EFAULT);
+ if (!mq_attr_ok(&attr))
+ return ERR_PTR(-EINVAL);
+ /* store for use during create */
+ dentry->d_fsdata = &attr;
+ }
+
+ ret = vfs_create(dir->d_inode, dentry, mode, NULL);
+ dentry->d_fsdata = NULL;
+ if (ret)
+ return ERR_PTR(ret);
+
+ filp = dentry_open(dentry, mqueue_mnt, oflag);
+ if (!IS_ERR(filp))
+ dget(dentry);
+
+ return filp;
+}
+
+/* Opens existing queue */
+static struct file *do_open(struct dentry *dentry, int oflag)
+{
+static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
+ MAY_READ | MAY_WRITE };
+ struct file *filp;
+
+ if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
+ return ERR_PTR(-EINVAL);
+
+ if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL))
+ return ERR_PTR(-EACCES);
+
+ filp = dentry_open(dentry, mqueue_mnt, oflag);
+
+ if (!IS_ERR(filp))
+ dget(dentry);
+
+ return filp;
+}
+
+asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
+ struct mq_attr __user *u_attr)
+{
+ struct dentry *dentry;
+ struct file *filp;
+ char *name;
+ int fd, error;
+
+ if (IS_ERR(name = getname(u_name)))
+ return PTR_ERR(name);
+
+ fd = get_unused_fd();
+ if (fd < 0)
+ goto out_putname;
+
+ down(&mqueue_mnt->mnt_root->d_inode->i_sem);
+ dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
+ if (IS_ERR(dentry)) {
+ error = PTR_ERR(dentry);
+ goto out_err;
+ }
+ mntget(mqueue_mnt);
+
+ if (oflag & O_CREAT) {
+ if (dentry->d_inode) { /* entry already exists */
+ filp = (oflag & O_EXCL) ? ERR_PTR(-EEXIST) :
+ do_open(dentry, oflag);
+ } else {
+ filp = do_create(mqueue_mnt->mnt_root, dentry,
+ oflag, mode, u_attr);
+ }
+ } else
+ filp = (dentry->d_inode) ? do_open(dentry, oflag) :
+ ERR_PTR(-ENOENT);
+
+ dput(dentry);
+
+ if (IS_ERR(filp)) {
+ error = PTR_ERR(filp);
+ goto out_putfd;
+ }
+
+ set_close_on_exec(fd, 1);
+ fd_install(fd, filp);
+ goto out_upsem;
+
+out_putfd:
+ mntput(mqueue_mnt);
+ put_unused_fd(fd);
+out_err:
+ fd = error;
+out_upsem:
+ up(&mqueue_mnt->mnt_root->d_inode->i_sem);
+out_putname:
+ putname(name);
+ return fd;
+}
+
+asmlinkage long sys_mq_unlink(const char __user *u_name)
+{
+ int err;
+ char *name;
+ struct dentry *dentry;
+ struct inode *inode = NULL;
+
+ name = getname(u_name);
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+
+ down(&mqueue_mnt->mnt_root->d_inode->i_sem);
+ dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
+ if (IS_ERR(dentry)) {
+ err = PTR_ERR(dentry);
+ goto out_unlock;
+ }
+
+ if (!dentry->d_inode) {
+ err = -ENOENT;
+ goto out_err;
+ }
+
+ inode = dentry->d_inode;
+ if (inode)
+ atomic_inc(&inode->i_count);
+
+ err = vfs_unlink(dentry->d_parent->d_inode, dentry);
+out_err:
+ dput(dentry);
+
+out_unlock:
+ up(&mqueue_mnt->mnt_root->d_inode->i_sem);
+ putname(name);
+ if (inode)
+ iput(inode);
+
+ return err;
+}
+
+/* Pipelined send and receive functions.
+ *
+ * If a receiver finds no waiting message, then it registers itself in the
+ * list of waiting receivers. A sender checks that list before adding the new
+ * message into the message array. If there is a waiting receiver, then it
+ * bypasses the message array and directly hands the message over to the
+ * receiver.
+ * The receiver accepts the message and returns without grabbing the queue
+ * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
+ * are necessary. The same algorithm is used for sysv semaphores, see
+ * ipc/sem.c fore more details.
+ *
+ * The same algorithm is used for senders.
+ */
+
+/* pipelined_send() - send a message directly to the task waiting in
+ * sys_mq_timedreceive() (without inserting message into a queue).
+ */
+static inline void pipelined_send(struct mqueue_inode_info *info,
+ struct msg_msg *message,
+ struct ext_wait_queue *receiver)
+{
+ receiver->msg = message;
+ list_del(&receiver->list);
+ receiver->state = STATE_PENDING;
+ wake_up_process(receiver->task);
+ wmb();
+ receiver->state = STATE_READY;
+}
+
+/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
+ * gets its message and put to the queue (we have one free place for sure). */
+static inline void pipelined_receive(struct mqueue_inode_info *info)
+{
+ struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
+
+ if (!sender) {
+ /* for poll */
+ wake_up_interruptible(&info->wait_q);
+ return;
+ }
+ msg_insert(sender->msg, info);
+ list_del(&sender->list);
+ sender->state = STATE_PENDING;
+ wake_up_process(sender->task);
+ wmb();
+ sender->state = STATE_READY;
+}
+
+asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
+ size_t msg_len, unsigned int msg_prio,
+ const struct timespec __user *u_abs_timeout)
+{
+ struct file *filp;
+ struct inode *inode;
+ struct ext_wait_queue wait;
+ struct ext_wait_queue *receiver;
+ struct msg_msg *msg_ptr;
+ struct mqueue_inode_info *info;
+ long timeout;
+ int ret;
+
+ if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
+ return -EINVAL;
+
+ timeout = prepare_timeout(u_abs_timeout);
+
+ ret = -EBADF;
+ filp = fget(mqdes);
+ if (unlikely(!filp))
+ goto out;
+
+ inode = filp->f_dentry->d_inode;
+ if (unlikely(filp->f_op != &mqueue_file_operations))
+ goto out_fput;
+ info = MQUEUE_I(inode);
+
+ if (unlikely(!(filp->f_mode & FMODE_WRITE)))
+ goto out_fput;
+
+ if (unlikely(msg_len > info->attr.mq_msgsize)) {
+ ret = -EMSGSIZE;
+ goto out_fput;
+ }
+
+ /* First try to allocate memory, before doing anything with
+ * existing queues. */
+ msg_ptr = load_msg(u_msg_ptr, msg_len);
+ if (IS_ERR(msg_ptr)) {
+ ret = PTR_ERR(msg_ptr);
+ goto out_fput;
+ }
+ msg_ptr->m_ts = msg_len;
+ msg_ptr->m_type = msg_prio;
+
+ spin_lock(&info->lock);
+
+ if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
+ if (filp->f_flags & O_NONBLOCK) {
+ spin_unlock(&info->lock);
+ ret = -EAGAIN;
+ } else if (unlikely(timeout < 0)) {
+ spin_unlock(&info->lock);
+ ret = timeout;
+ } else {
+ wait.task = current;
+ wait.msg = (void *) msg_ptr;
+ wait.state = STATE_NONE;
+ ret = wq_sleep(info, SEND, timeout, &wait);
+ }
+ if (ret < 0)
+ free_msg(msg_ptr);
+ } else {
+ receiver = wq_get_first_waiter(info, RECV);
+ if (receiver) {
+ pipelined_send(info, msg_ptr, receiver);
+ } else {
+ /* adds message to the queue */
+ msg_insert(msg_ptr, info);
+ __do_notify(info);
+ }
+ inode->i_atime = inode->i_mtime = inode->i_ctime =
+ CURRENT_TIME;
+ spin_unlock(&info->lock);
+ ret = 0;
+ }
+out_fput:
+ fput(filp);
+out:
+ return ret;
+}
+
+asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
+ size_t msg_len, unsigned int __user *u_msg_prio,
+ const struct timespec __user *u_abs_timeout)
+{
+ long timeout;
+ ssize_t ret;
+ struct msg_msg *msg_ptr;
+ struct file *filp;
+ struct inode *inode;
+ struct mqueue_inode_info *info;
+ struct ext_wait_queue wait;
+
+ timeout = prepare_timeout(u_abs_timeout);
+
+ ret = -EBADF;
+ filp = fget(mqdes);
+ if (unlikely(!filp))
+ goto out;
+
+ inode = filp->f_dentry->d_inode;
+ if (unlikely(filp->f_op != &mqueue_file_operations))
+ goto out_fput;
+ info = MQUEUE_I(inode);
+
+ if (unlikely(!(filp->f_mode & FMODE_READ)))
+ goto out_fput;
+
+ /* checks if buffer is big enough */
+ if (unlikely(msg_len < info->attr.mq_msgsize)) {
+ ret = -EMSGSIZE;
+ goto out_fput;
+ }
+
+ spin_lock(&info->lock);
+ if (info->attr.mq_curmsgs == 0) {
+ if (filp->f_flags & O_NONBLOCK) {
+ spin_unlock(&info->lock);
+ ret = -EAGAIN;
+ msg_ptr = NULL;
+ } else if (unlikely(timeout < 0)) {
+ spin_unlock(&info->lock);
+ ret = timeout;
+ msg_ptr = NULL;
+ } else {
+ wait.task = current;
+ wait.state = STATE_NONE;
+ ret = wq_sleep(info, RECV, timeout, &wait);
+ msg_ptr = wait.msg;
+ }
+ } else {
+ msg_ptr = msg_get(info);
+
+ inode->i_atime = inode->i_mtime = inode->i_ctime =
+ CURRENT_TIME;
+
+ /* There is now free space in queue. */
+ pipelined_receive(info);
+ spin_unlock(&info->lock);
+ ret = 0;
+ }
+ if (ret == 0) {
+ ret = msg_ptr->m_ts;
+
+ if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
+ store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
+ ret = -EFAULT;
+ }
+ free_msg(msg_ptr);
+ }
+out_fput:
+ fput(filp);
+out:
+ return ret;
+}
+
+/*
+ * Notes: the case when user wants us to deregister (with NULL as pointer)
+ * and he isn't currently owner of notification, will be silently discarded.
+ * It isn't explicitly defined in the POSIX.
+ */
+asmlinkage long sys_mq_notify(mqd_t mqdes,
+ const struct sigevent __user *u_notification)
+{
+ int ret;
+ struct file *filp;
+ struct sock *sock;
+ struct inode *inode;
+ struct sigevent notification;
+ struct mqueue_inode_info *info;
+ struct sk_buff *nc;
+
+ nc = NULL;
+ sock = NULL;
+ if (u_notification != NULL) {
+ if (copy_from_user(&notification, u_notification,
+ sizeof(struct sigevent)))
+ return -EFAULT;
+
+ if (unlikely(notification.sigev_notify != SIGEV_NONE &&
+ notification.sigev_notify != SIGEV_SIGNAL &&
+ notification.sigev_notify != SIGEV_THREAD))
+ return -EINVAL;
+ if (notification.sigev_notify == SIGEV_SIGNAL &&
+ (notification.sigev_signo < 0 ||
+ notification.sigev_signo > _NSIG)) {
+ return -EINVAL;
+ }
+ if (notification.sigev_notify == SIGEV_THREAD) {
+ /* create the notify skb */
+ nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
+ ret = -ENOMEM;
+ if (!nc)
+ goto out;
+ ret = -EFAULT;
+ if (copy_from_user(nc->data,
+ notification.sigev_value.sival_ptr,
+ NOTIFY_COOKIE_LEN)) {
+ goto out;
+ }
+
+ /* TODO: add a header? */
+ skb_put(nc, NOTIFY_COOKIE_LEN);
+ /* and attach it to the socket */
+retry:
+ filp = fget(notification.sigev_signo);
+ ret = -EBADF;
+ if (!filp)
+ goto out;
+ sock = netlink_getsockbyfilp(filp);
+ fput(filp);
+ if (IS_ERR(sock)) {
+ ret = PTR_ERR(sock);
+ sock = NULL;
+ goto out;
+ }
+
+ ret = netlink_attachskb(sock, nc, 0, MAX_SCHEDULE_TIMEOUT);
+ if (ret == 1)
+ goto retry;
+ if (ret) {
+ sock = NULL;
+ nc = NULL;
+ goto out;
+ }
+ }
+ }
+
+ ret = -EBADF;
+ filp = fget(mqdes);
+ if (!filp)
+ goto out;
+
+ inode = filp->f_dentry->d_inode;
+ if (unlikely(filp->f_op != &mqueue_file_operations))
+ goto out_fput;
+ info = MQUEUE_I(inode);
+
+ ret = 0;
+ spin_lock(&info->lock);
+ if (u_notification == NULL) {
+ if (info->notify_owner == current->tgid) {
+ remove_notification(info);
+ inode->i_atime = inode->i_ctime = CURRENT_TIME;
+ }
+ } else if (info->notify_owner != 0) {
+ ret = -EBUSY;
+ } else {
+ switch (notification.sigev_notify) {
+ case SIGEV_NONE:
+ info->notify.sigev_notify = SIGEV_NONE;
+ break;
+ case SIGEV_THREAD:
+ info->notify_sock = sock;
+ info->notify_cookie = nc;
+ sock = NULL;
+ nc = NULL;
+ info->notify.sigev_notify = SIGEV_THREAD;
+ break;
+ case SIGEV_SIGNAL:
+ info->notify.sigev_signo = notification.sigev_signo;
+ info->notify.sigev_value = notification.sigev_value;
+ info->notify.sigev_notify = SIGEV_SIGNAL;
+ break;
+ }
+ info->notify_owner = current->tgid;
+ inode->i_atime = inode->i_ctime = CURRENT_TIME;
+ }
+ spin_unlock(&info->lock);
+out_fput:
+ fput(filp);
+out:
+ if (sock) {
+ netlink_detachskb(sock, nc);
+ } else if (nc) {
+ dev_kfree_skb(nc);
+ }
+ return ret;
+}
+
+asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
+ const struct mq_attr __user *u_mqstat,
+ struct mq_attr __user *u_omqstat)
+{
+ int ret;
+ struct mq_attr mqstat, omqstat;
+ struct file *filp;
+ struct inode *inode;
+ struct mqueue_inode_info *info;
+
+ if (u_mqstat != NULL) {
+ if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
+ return -EFAULT;
+ if (mqstat.mq_flags & (~O_NONBLOCK))
+ return -EINVAL;
+ }
+
+ ret = -EBADF;
+ filp = fget(mqdes);
+ if (!filp)
+ goto out;
+
+ inode = filp->f_dentry->d_inode;
+ if (unlikely(filp->f_op != &mqueue_file_operations))
+ goto out_fput;
+ info = MQUEUE_I(inode);
+
+ spin_lock(&info->lock);
+
+ omqstat = info->attr;
+ omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
+ if (u_mqstat) {
+ if (mqstat.mq_flags & O_NONBLOCK)
+ filp->f_flags |= O_NONBLOCK;
+ else
+ filp->f_flags &= ~O_NONBLOCK;
+
+ inode->i_atime = inode->i_ctime = CURRENT_TIME;
+ }
+
+ spin_unlock(&info->lock);
+
+ ret = 0;
+ if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
+ sizeof(struct mq_attr)))
+ ret = -EFAULT;
+
+out_fput:
+ fput(filp);
+out:
+ return ret;
+}
+
+static struct inode_operations mqueue_dir_inode_operations = {
+ .lookup = simple_lookup,
+ .create = mqueue_create,
+ .unlink = mqueue_unlink,
+};
+
+static struct file_operations mqueue_file_operations = {
+ .flush = mqueue_flush_file,
+ .poll = mqueue_poll_file,
+ .read = mqueue_read_file,
+};
+
+static struct super_operations mqueue_super_ops = {
+ .alloc_inode = mqueue_alloc_inode,
+ .destroy_inode = mqueue_destroy_inode,
+ .statfs = simple_statfs,
+ .delete_inode = mqueue_delete_inode,
+ .drop_inode = generic_delete_inode,
+};
+
+static struct file_system_type mqueue_fs_type = {
+ .name = "mqueue",
+ .get_sb = mqueue_get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+static int msg_max_limit_min = DFLT_MSGMAX;
+static int msg_max_limit_max = HARD_MSGMAX;
+
+static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
+static int msg_maxsize_limit_max = INT_MAX;
+
+static ctl_table mq_sysctls[] = {
+ {
+ .ctl_name = CTL_QUEUESMAX,
+ .procname = "queues_max",
+ .data = &queues_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
+ .ctl_name = CTL_MSGMAX,
+ .procname = "msg_max",
+ .data = &msg_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &msg_max_limit_min,
+ .extra2 = &msg_max_limit_max,
+ },
+ {
+ .ctl_name = CTL_MSGSIZEMAX,
+ .procname = "msgsize_max",
+ .data = &msgsize_max,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = &msg_maxsize_limit_min,
+ .extra2 = &msg_maxsize_limit_max,
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_dir[] = {
+ {
+ .ctl_name = FS_MQUEUE,
+ .procname = "mqueue",
+ .mode = 0555,
+ .child = mq_sysctls,
+ },
+ { .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_root[] = {
+ {
+ .ctl_name = CTL_FS,
+ .procname = "fs",
+ .mode = 0555,
+ .child = mq_sysctl_dir,
+ },
+ { .ctl_name = 0 }
+};
+
+static int __init init_mqueue_fs(void)
+{
+ int error;
+
+ mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
+ sizeof(struct mqueue_inode_info), 0,
+ SLAB_HWCACHE_ALIGN, init_once, NULL);
+ if (mqueue_inode_cachep == NULL)
+ return -ENOMEM;
+
+ /* ignore failues - they are not fatal */
+ mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0);
+
+ error = register_filesystem(&mqueue_fs_type);
+ if (error)
+ goto out_sysctl;
+
+ if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
+ error = PTR_ERR(mqueue_mnt);
+ goto out_filesystem;
+ }
+
+ /* internal initialization - not common for vfs */
+ queues_count = 0;
+ spin_lock_init(&mq_lock);
+
+ return 0;
+
+out_filesystem:
+ unregister_filesystem(&mqueue_fs_type);
+out_sysctl:
+ if (mq_sysctl_table)
+ unregister_sysctl_table(mq_sysctl_table);
+ if (kmem_cache_destroy(mqueue_inode_cachep)) {
+ printk(KERN_INFO
+ "mqueue_inode_cache: not all structures were freed\n");
+ }
+ return error;
+}
+
+__initcall(init_mqueue_fs);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-27 14:36:42 +0000