2 * POSIX message queues filesystem for Linux.
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
13 * This file is released under the GPL.
16 #include <linux/capability.h>
17 #include <linux/init.h>
18 #include <linux/pagemap.h>
19 #include <linux/file.h>
20 #include <linux/mount.h>
21 #include <linux/namei.h>
22 #include <linux/sysctl.h>
23 #include <linux/poll.h>
24 #include <linux/mqueue.h>
25 #include <linux/msg.h>
26 #include <linux/skbuff.h>
27 #include <linux/netlink.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/signal.h>
31 #include <linux/mutex.h>
32 #include <linux/nsproxy.h>
33 #include <linux/pid.h>
34 #include <linux/ipc_namespace.h>
39 #define MQUEUE_MAGIC 0x19800202
40 #define DIRENT_SIZE 20
41 #define FILENT_SIZE 80
47 #define STATE_PENDING 1
50 struct ext_wait_queue { /* queue of sleeping tasks */
51 struct task_struct *task;
52 struct list_head list;
53 struct msg_msg *msg; /* ptr of loaded message */
54 int state; /* one of STATE_* values */
57 struct mqueue_inode_info {
59 struct inode vfs_inode;
60 wait_queue_head_t wait_q;
62 struct msg_msg **messages;
65 struct sigevent notify;
66 struct pid* notify_owner;
67 struct user_struct *user; /* user who created, for accounting */
68 struct sock *notify_sock;
69 struct sk_buff *notify_cookie;
71 /* for tasks waiting for free space and messages, respectively */
72 struct ext_wait_queue e_wait_q[2];
74 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
77 static const struct inode_operations mqueue_dir_inode_operations;
78 static const struct file_operations mqueue_file_operations;
79 static const struct super_operations mqueue_super_ops;
80 static void remove_notification(struct mqueue_inode_info *info);
82 static struct kmem_cache *mqueue_inode_cachep;
84 static struct ctl_table_header * mq_sysctl_table;
86 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
88 return container_of(inode, struct mqueue_inode_info, vfs_inode);
92 * This routine should be called with the mq_lock held.
94 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
96 return get_ipc_ns(inode->i_sb->s_fs_info);
99 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
101 struct ipc_namespace *ns;
104 ns = __get_ns_from_inode(inode);
105 spin_unlock(&mq_lock);
109 static struct inode *mqueue_get_inode(struct super_block *sb,
110 struct ipc_namespace *ipc_ns, int mode,
111 struct mq_attr *attr)
113 struct user_struct *u = current_user();
116 inode = new_inode(sb);
118 inode->i_mode = mode;
119 inode->i_uid = current_fsuid();
120 inode->i_gid = current_fsgid();
121 inode->i_mtime = inode->i_ctime = inode->i_atime =
125 struct mqueue_inode_info *info;
126 struct task_struct *p = current;
127 unsigned long mq_bytes, mq_msg_tblsz;
129 inode->i_fop = &mqueue_file_operations;
130 inode->i_size = FILENT_SIZE;
131 /* mqueue specific info */
132 info = MQUEUE_I(inode);
133 spin_lock_init(&info->lock);
134 init_waitqueue_head(&info->wait_q);
135 INIT_LIST_HEAD(&info->e_wait_q[0].list);
136 INIT_LIST_HEAD(&info->e_wait_q[1].list);
137 info->messages = NULL;
138 info->notify_owner = NULL;
140 info->user = NULL; /* set when all is ok */
141 memset(&info->attr, 0, sizeof(info->attr));
142 info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
143 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
145 info->attr.mq_maxmsg = attr->mq_maxmsg;
146 info->attr.mq_msgsize = attr->mq_msgsize;
148 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
149 mq_bytes = (mq_msg_tblsz +
150 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
153 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
154 u->mq_bytes + mq_bytes >
155 p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
156 spin_unlock(&mq_lock);
159 u->mq_bytes += mq_bytes;
160 spin_unlock(&mq_lock);
162 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
163 if (!info->messages) {
165 u->mq_bytes -= mq_bytes;
166 spin_unlock(&mq_lock);
170 info->user = get_uid(u);
171 } else if (S_ISDIR(mode)) {
173 /* Some things misbehave if size == 0 on a directory */
174 inode->i_size = 2 * DIRENT_SIZE;
175 inode->i_op = &mqueue_dir_inode_operations;
176 inode->i_fop = &simple_dir_operations;
181 make_bad_inode(inode);
186 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
189 struct ipc_namespace *ns = data;
192 sb->s_blocksize = PAGE_CACHE_SIZE;
193 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
194 sb->s_magic = MQUEUE_MAGIC;
195 sb->s_op = &mqueue_super_ops;
197 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
204 sb->s_root = d_alloc_root(inode);
214 static int mqueue_get_sb(struct file_system_type *fs_type,
215 int flags, const char *dev_name,
216 void *data, struct vfsmount *mnt)
218 if (!(flags & MS_KERNMOUNT))
219 data = current->nsproxy->ipc_ns;
220 return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);
223 static void init_once(void *foo)
225 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
227 inode_init_once(&p->vfs_inode);
230 static struct inode *mqueue_alloc_inode(struct super_block *sb)
232 struct mqueue_inode_info *ei;
234 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
237 return &ei->vfs_inode;
240 static void mqueue_destroy_inode(struct inode *inode)
242 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
245 static void mqueue_delete_inode(struct inode *inode)
247 struct mqueue_inode_info *info;
248 struct user_struct *user;
249 unsigned long mq_bytes;
251 struct ipc_namespace *ipc_ns;
253 if (S_ISDIR(inode->i_mode)) {
257 ipc_ns = get_ns_from_inode(inode);
258 info = MQUEUE_I(inode);
259 spin_lock(&info->lock);
260 for (i = 0; i < info->attr.mq_curmsgs; i++)
261 free_msg(info->messages[i]);
262 kfree(info->messages);
263 spin_unlock(&info->lock);
267 mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
268 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
272 user->mq_bytes -= mq_bytes;
274 * get_ns_from_inode() ensures that the
275 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
276 * to which we now hold a reference, or it is NULL.
277 * We can't put it here under mq_lock, though.
280 ipc_ns->mq_queues_count--;
281 spin_unlock(&mq_lock);
288 static int mqueue_create(struct inode *dir, struct dentry *dentry,
289 int mode, struct nameidata *nd)
292 struct mq_attr *attr = dentry->d_fsdata;
294 struct ipc_namespace *ipc_ns;
297 ipc_ns = __get_ns_from_inode(dir);
302 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
303 !capable(CAP_SYS_RESOURCE)) {
307 ipc_ns->mq_queues_count++;
308 spin_unlock(&mq_lock);
310 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
314 ipc_ns->mq_queues_count--;
319 dir->i_size += DIRENT_SIZE;
320 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
322 d_instantiate(dentry, inode);
326 spin_unlock(&mq_lock);
332 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
334 struct inode *inode = dentry->d_inode;
336 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
337 dir->i_size -= DIRENT_SIZE;
344 * This is routine for system read from queue file.
345 * To avoid mess with doing here some sort of mq_receive we allow
346 * to read only queue size & notification info (the only values
347 * that are interesting from user point of view and aren't accessible
348 * through std routines)
350 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
351 size_t count, loff_t *off)
353 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
354 char buffer[FILENT_SIZE];
357 spin_lock(&info->lock);
358 snprintf(buffer, sizeof(buffer),
359 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
361 info->notify_owner ? info->notify.sigev_notify : 0,
362 (info->notify_owner &&
363 info->notify.sigev_notify == SIGEV_SIGNAL) ?
364 info->notify.sigev_signo : 0,
365 pid_vnr(info->notify_owner));
366 spin_unlock(&info->lock);
367 buffer[sizeof(buffer)-1] = '\0';
369 ret = simple_read_from_buffer(u_data, count, off, buffer,
374 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
378 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
380 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
382 spin_lock(&info->lock);
383 if (task_tgid(current) == info->notify_owner)
384 remove_notification(info);
386 spin_unlock(&info->lock);
390 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
392 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
395 poll_wait(filp, &info->wait_q, poll_tab);
397 spin_lock(&info->lock);
398 if (info->attr.mq_curmsgs)
399 retval = POLLIN | POLLRDNORM;
401 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
402 retval |= POLLOUT | POLLWRNORM;
403 spin_unlock(&info->lock);
408 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
409 static void wq_add(struct mqueue_inode_info *info, int sr,
410 struct ext_wait_queue *ewp)
412 struct ext_wait_queue *walk;
416 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
417 if (walk->task->static_prio <= current->static_prio) {
418 list_add_tail(&ewp->list, &walk->list);
422 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
426 * Puts current task to sleep. Caller must hold queue lock. After return
430 static int wq_sleep(struct mqueue_inode_info *info, int sr,
431 long timeout, struct ext_wait_queue *ewp)
436 wq_add(info, sr, ewp);
439 set_current_state(TASK_INTERRUPTIBLE);
441 spin_unlock(&info->lock);
442 time = schedule_timeout(timeout);
444 while (ewp->state == STATE_PENDING)
447 if (ewp->state == STATE_READY) {
451 spin_lock(&info->lock);
452 if (ewp->state == STATE_READY) {
456 if (signal_pending(current)) {
457 retval = -ERESTARTSYS;
465 list_del(&ewp->list);
467 spin_unlock(&info->lock);
473 * Returns waiting task that should be serviced first or NULL if none exists
475 static struct ext_wait_queue *wq_get_first_waiter(
476 struct mqueue_inode_info *info, int sr)
478 struct list_head *ptr;
480 ptr = info->e_wait_q[sr].list.prev;
481 if (ptr == &info->e_wait_q[sr].list)
483 return list_entry(ptr, struct ext_wait_queue, list);
486 /* Auxiliary functions to manipulate messages' list */
487 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
491 k = info->attr.mq_curmsgs - 1;
492 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
493 info->messages[k + 1] = info->messages[k];
496 info->attr.mq_curmsgs++;
497 info->qsize += ptr->m_ts;
498 info->messages[k + 1] = ptr;
501 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
503 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
504 return info->messages[info->attr.mq_curmsgs];
507 static inline void set_cookie(struct sk_buff *skb, char code)
509 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
513 * The next function is only to split too long sys_mq_timedsend
515 static void __do_notify(struct mqueue_inode_info *info)
518 * invoked when there is registered process and there isn't process
519 * waiting synchronously for message AND state of queue changed from
520 * empty to not empty. Here we are sure that no one is waiting
522 if (info->notify_owner &&
523 info->attr.mq_curmsgs == 1) {
524 struct siginfo sig_i;
525 switch (info->notify.sigev_notify) {
531 sig_i.si_signo = info->notify.sigev_signo;
533 sig_i.si_code = SI_MESGQ;
534 sig_i.si_value = info->notify.sigev_value;
535 sig_i.si_pid = task_tgid_nr_ns(current,
536 ns_of_pid(info->notify_owner));
537 sig_i.si_uid = current_uid();
539 kill_pid_info(info->notify.sigev_signo,
540 &sig_i, info->notify_owner);
543 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
544 netlink_sendskb(info->notify_sock, info->notify_cookie);
547 /* after notification unregisters process */
548 put_pid(info->notify_owner);
549 info->notify_owner = NULL;
551 wake_up(&info->wait_q);
554 static long prepare_timeout(struct timespec *p)
556 struct timespec nowts;
560 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
561 || p->tv_nsec >= NSEC_PER_SEC))
563 nowts = CURRENT_TIME;
564 /* first subtract as jiffies can't be too big */
565 p->tv_sec -= nowts.tv_sec;
566 if (p->tv_nsec < nowts.tv_nsec) {
567 p->tv_nsec += NSEC_PER_SEC;
570 p->tv_nsec -= nowts.tv_nsec;
574 timeout = timespec_to_jiffies(p) + 1;
576 return MAX_SCHEDULE_TIMEOUT;
581 static void remove_notification(struct mqueue_inode_info *info)
583 if (info->notify_owner != NULL &&
584 info->notify.sigev_notify == SIGEV_THREAD) {
585 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
586 netlink_sendskb(info->notify_sock, info->notify_cookie);
588 put_pid(info->notify_owner);
589 info->notify_owner = NULL;
592 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
594 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
596 if (capable(CAP_SYS_RESOURCE)) {
597 if (attr->mq_maxmsg > HARD_MSGMAX)
600 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
601 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
604 /* check for overflow */
605 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
607 if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
608 (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
609 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
615 * Invoked when creating a new queue via sys_mq_open
617 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
618 struct dentry *dentry, int oflag, mode_t mode,
619 struct mq_attr *attr)
621 const struct cred *cred = current_cred();
627 if (!mq_attr_ok(ipc_ns, attr))
629 /* store for use during create */
630 dentry->d_fsdata = attr;
633 mode &= ~current_umask();
634 ret = mnt_want_write(ipc_ns->mq_mnt);
637 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
638 dentry->d_fsdata = NULL;
642 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
644 * dentry_open() took a persistent mnt_want_write(),
645 * so we can now drop this one.
647 mnt_drop_write(ipc_ns->mq_mnt);
651 mnt_drop_write(ipc_ns->mq_mnt);
654 mntput(ipc_ns->mq_mnt);
658 /* Opens existing queue */
659 static struct file *do_open(struct ipc_namespace *ipc_ns,
660 struct dentry *dentry, int oflag)
662 const struct cred *cred = current_cred();
664 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
665 MAY_READ | MAY_WRITE };
667 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
669 mntput(ipc_ns->mq_mnt);
670 return ERR_PTR(-EINVAL);
673 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
675 mntput(ipc_ns->mq_mnt);
676 return ERR_PTR(-EACCES);
679 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
682 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
683 struct mq_attr __user *, u_attr)
685 struct dentry *dentry;
690 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
692 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
695 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
697 if (IS_ERR(name = getname(u_name)))
698 return PTR_ERR(name);
700 fd = get_unused_fd_flags(O_CLOEXEC);
704 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
705 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
706 if (IS_ERR(dentry)) {
707 error = PTR_ERR(dentry);
710 mntget(ipc_ns->mq_mnt);
712 if (oflag & O_CREAT) {
713 if (dentry->d_inode) { /* entry already exists */
714 audit_inode(name, dentry);
718 filp = do_open(ipc_ns, dentry, oflag);
720 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
722 u_attr ? &attr : NULL);
726 if (!dentry->d_inode)
728 audit_inode(name, dentry);
729 filp = do_open(ipc_ns, dentry, oflag);
733 error = PTR_ERR(filp);
737 fd_install(fd, filp);
742 mntput(ipc_ns->mq_mnt);
747 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
753 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
757 struct dentry *dentry;
758 struct inode *inode = NULL;
759 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
761 name = getname(u_name);
763 return PTR_ERR(name);
765 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
767 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
768 if (IS_ERR(dentry)) {
769 err = PTR_ERR(dentry);
773 if (!dentry->d_inode) {
778 inode = dentry->d_inode;
780 atomic_inc(&inode->i_count);
781 err = mnt_want_write(ipc_ns->mq_mnt);
784 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
785 mnt_drop_write(ipc_ns->mq_mnt);
790 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
798 /* Pipelined send and receive functions.
800 * If a receiver finds no waiting message, then it registers itself in the
801 * list of waiting receivers. A sender checks that list before adding the new
802 * message into the message array. If there is a waiting receiver, then it
803 * bypasses the message array and directly hands the message over to the
805 * The receiver accepts the message and returns without grabbing the queue
806 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
807 * are necessary. The same algorithm is used for sysv semaphores, see
808 * ipc/sem.c for more details.
810 * The same algorithm is used for senders.
813 /* pipelined_send() - send a message directly to the task waiting in
814 * sys_mq_timedreceive() (without inserting message into a queue).
816 static inline void pipelined_send(struct mqueue_inode_info *info,
817 struct msg_msg *message,
818 struct ext_wait_queue *receiver)
820 receiver->msg = message;
821 list_del(&receiver->list);
822 receiver->state = STATE_PENDING;
823 wake_up_process(receiver->task);
825 receiver->state = STATE_READY;
828 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
829 * gets its message and put to the queue (we have one free place for sure). */
830 static inline void pipelined_receive(struct mqueue_inode_info *info)
832 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
836 wake_up_interruptible(&info->wait_q);
839 msg_insert(sender->msg, info);
840 list_del(&sender->list);
841 sender->state = STATE_PENDING;
842 wake_up_process(sender->task);
844 sender->state = STATE_READY;
847 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
848 size_t, msg_len, unsigned int, msg_prio,
849 const struct timespec __user *, u_abs_timeout)
853 struct ext_wait_queue wait;
854 struct ext_wait_queue *receiver;
855 struct msg_msg *msg_ptr;
856 struct mqueue_inode_info *info;
857 struct timespec ts, *p = NULL;
862 if (copy_from_user(&ts, u_abs_timeout,
863 sizeof(struct timespec)))
868 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
871 audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
872 timeout = prepare_timeout(p);
879 inode = filp->f_path.dentry->d_inode;
880 if (unlikely(filp->f_op != &mqueue_file_operations))
882 info = MQUEUE_I(inode);
883 audit_inode(NULL, filp->f_path.dentry);
885 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
888 if (unlikely(msg_len > info->attr.mq_msgsize)) {
893 /* First try to allocate memory, before doing anything with
894 * existing queues. */
895 msg_ptr = load_msg(u_msg_ptr, msg_len);
896 if (IS_ERR(msg_ptr)) {
897 ret = PTR_ERR(msg_ptr);
900 msg_ptr->m_ts = msg_len;
901 msg_ptr->m_type = msg_prio;
903 spin_lock(&info->lock);
905 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
906 if (filp->f_flags & O_NONBLOCK) {
907 spin_unlock(&info->lock);
909 } else if (unlikely(timeout < 0)) {
910 spin_unlock(&info->lock);
914 wait.msg = (void *) msg_ptr;
915 wait.state = STATE_NONE;
916 ret = wq_sleep(info, SEND, timeout, &wait);
921 receiver = wq_get_first_waiter(info, RECV);
923 pipelined_send(info, msg_ptr, receiver);
925 /* adds message to the queue */
926 msg_insert(msg_ptr, info);
929 inode->i_atime = inode->i_mtime = inode->i_ctime =
931 spin_unlock(&info->lock);
940 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
941 size_t, msg_len, unsigned int __user *, u_msg_prio,
942 const struct timespec __user *, u_abs_timeout)
946 struct msg_msg *msg_ptr;
949 struct mqueue_inode_info *info;
950 struct ext_wait_queue wait;
951 struct timespec ts, *p = NULL;
954 if (copy_from_user(&ts, u_abs_timeout,
955 sizeof(struct timespec)))
960 audit_mq_sendrecv(mqdes, msg_len, 0, p);
961 timeout = prepare_timeout(p);
968 inode = filp->f_path.dentry->d_inode;
969 if (unlikely(filp->f_op != &mqueue_file_operations))
971 info = MQUEUE_I(inode);
972 audit_inode(NULL, filp->f_path.dentry);
974 if (unlikely(!(filp->f_mode & FMODE_READ)))
977 /* checks if buffer is big enough */
978 if (unlikely(msg_len < info->attr.mq_msgsize)) {
983 spin_lock(&info->lock);
984 if (info->attr.mq_curmsgs == 0) {
985 if (filp->f_flags & O_NONBLOCK) {
986 spin_unlock(&info->lock);
989 } else if (unlikely(timeout < 0)) {
990 spin_unlock(&info->lock);
995 wait.state = STATE_NONE;
996 ret = wq_sleep(info, RECV, timeout, &wait);
1000 msg_ptr = msg_get(info);
1002 inode->i_atime = inode->i_mtime = inode->i_ctime =
1005 /* There is now free space in queue. */
1006 pipelined_receive(info);
1007 spin_unlock(&info->lock);
1011 ret = msg_ptr->m_ts;
1013 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1014 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1026 * Notes: the case when user wants us to deregister (with NULL as pointer)
1027 * and he isn't currently owner of notification, will be silently discarded.
1028 * It isn't explicitly defined in the POSIX.
1030 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1031 const struct sigevent __user *, u_notification)
1036 struct inode *inode;
1037 struct sigevent notification;
1038 struct mqueue_inode_info *info;
1041 if (u_notification) {
1042 if (copy_from_user(¬ification, u_notification,
1043 sizeof(struct sigevent)))
1047 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1051 if (u_notification != NULL) {
1052 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1053 notification.sigev_notify != SIGEV_SIGNAL &&
1054 notification.sigev_notify != SIGEV_THREAD))
1056 if (notification.sigev_notify == SIGEV_SIGNAL &&
1057 !valid_signal(notification.sigev_signo)) {
1060 if (notification.sigev_notify == SIGEV_THREAD) {
1063 /* create the notify skb */
1064 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1069 if (copy_from_user(nc->data,
1070 notification.sigev_value.sival_ptr,
1071 NOTIFY_COOKIE_LEN)) {
1075 /* TODO: add a header? */
1076 skb_put(nc, NOTIFY_COOKIE_LEN);
1077 /* and attach it to the socket */
1079 filp = fget(notification.sigev_signo);
1083 sock = netlink_getsockbyfilp(filp);
1086 ret = PTR_ERR(sock);
1091 timeo = MAX_SCHEDULE_TIMEOUT;
1092 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1108 inode = filp->f_path.dentry->d_inode;
1109 if (unlikely(filp->f_op != &mqueue_file_operations))
1111 info = MQUEUE_I(inode);
1114 spin_lock(&info->lock);
1115 if (u_notification == NULL) {
1116 if (info->notify_owner == task_tgid(current)) {
1117 remove_notification(info);
1118 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1120 } else if (info->notify_owner != NULL) {
1123 switch (notification.sigev_notify) {
1125 info->notify.sigev_notify = SIGEV_NONE;
1128 info->notify_sock = sock;
1129 info->notify_cookie = nc;
1132 info->notify.sigev_notify = SIGEV_THREAD;
1135 info->notify.sigev_signo = notification.sigev_signo;
1136 info->notify.sigev_value = notification.sigev_value;
1137 info->notify.sigev_notify = SIGEV_SIGNAL;
1141 info->notify_owner = get_pid(task_tgid(current));
1142 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1144 spin_unlock(&info->lock);
1149 netlink_detachskb(sock, nc);
1156 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1157 const struct mq_attr __user *, u_mqstat,
1158 struct mq_attr __user *, u_omqstat)
1161 struct mq_attr mqstat, omqstat;
1163 struct inode *inode;
1164 struct mqueue_inode_info *info;
1166 if (u_mqstat != NULL) {
1167 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1169 if (mqstat.mq_flags & (~O_NONBLOCK))
1178 inode = filp->f_path.dentry->d_inode;
1179 if (unlikely(filp->f_op != &mqueue_file_operations))
1181 info = MQUEUE_I(inode);
1183 spin_lock(&info->lock);
1185 omqstat = info->attr;
1186 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1188 audit_mq_getsetattr(mqdes, &mqstat);
1189 spin_lock(&filp->f_lock);
1190 if (mqstat.mq_flags & O_NONBLOCK)
1191 filp->f_flags |= O_NONBLOCK;
1193 filp->f_flags &= ~O_NONBLOCK;
1194 spin_unlock(&filp->f_lock);
1196 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1199 spin_unlock(&info->lock);
1202 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1203 sizeof(struct mq_attr)))
1212 static const struct inode_operations mqueue_dir_inode_operations = {
1213 .lookup = simple_lookup,
1214 .create = mqueue_create,
1215 .unlink = mqueue_unlink,
1218 static const struct file_operations mqueue_file_operations = {
1219 .flush = mqueue_flush_file,
1220 .poll = mqueue_poll_file,
1221 .read = mqueue_read_file,
1224 static const struct super_operations mqueue_super_ops = {
1225 .alloc_inode = mqueue_alloc_inode,
1226 .destroy_inode = mqueue_destroy_inode,
1227 .statfs = simple_statfs,
1228 .delete_inode = mqueue_delete_inode,
1229 .drop_inode = generic_delete_inode,
1232 static struct file_system_type mqueue_fs_type = {
1234 .get_sb = mqueue_get_sb,
1235 .kill_sb = kill_litter_super,
1238 int mq_init_ns(struct ipc_namespace *ns)
1240 ns->mq_queues_count = 0;
1241 ns->mq_queues_max = DFLT_QUEUESMAX;
1242 ns->mq_msg_max = DFLT_MSGMAX;
1243 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1245 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1246 if (IS_ERR(ns->mq_mnt)) {
1247 int err = PTR_ERR(ns->mq_mnt);
1254 void mq_clear_sbinfo(struct ipc_namespace *ns)
1256 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1259 void mq_put_mnt(struct ipc_namespace *ns)
1264 static int __init init_mqueue_fs(void)
1268 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1269 sizeof(struct mqueue_inode_info), 0,
1270 SLAB_HWCACHE_ALIGN, init_once);
1271 if (mqueue_inode_cachep == NULL)
1274 /* ignore failues - they are not fatal */
1275 mq_sysctl_table = mq_register_sysctl_table();
1277 error = register_filesystem(&mqueue_fs_type);
1281 spin_lock_init(&mq_lock);
1283 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1284 if (IS_ERR(init_ipc_ns.mq_mnt)) {
1285 error = PTR_ERR(init_ipc_ns.mq_mnt);
1286 goto out_filesystem;
1292 unregister_filesystem(&mqueue_fs_type);
1294 if (mq_sysctl_table)
1295 unregister_sysctl_table(mq_sysctl_table);
1296 kmem_cache_destroy(mqueue_inode_cachep);
1300 __initcall(init_mqueue_fs);