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>
38 #define MQUEUE_MAGIC 0x19800202
39 #define DIRENT_SIZE 20
40 #define FILENT_SIZE 80
46 #define STATE_PENDING 1
50 #define DFLT_QUEUESMAX 256 /* max number of message queues */
51 #define DFLT_MSGMAX 10 /* max number of messages in each queue */
52 #define HARD_MSGMAX (131072/sizeof(void*))
53 #define DFLT_MSGSIZEMAX 8192 /* max message size */
56 struct ext_wait_queue { /* queue of sleeping tasks */
57 struct task_struct *task;
58 struct list_head list;
59 struct msg_msg *msg; /* ptr of loaded message */
60 int state; /* one of STATE_* values */
63 struct mqueue_inode_info {
65 struct inode vfs_inode;
66 wait_queue_head_t wait_q;
68 struct msg_msg **messages;
71 struct sigevent notify;
72 struct pid* notify_owner;
73 struct user_struct *user; /* user who created, for accounting */
74 struct sock *notify_sock;
75 struct sk_buff *notify_cookie;
77 /* for tasks waiting for free space and messages, respectively */
78 struct ext_wait_queue e_wait_q[2];
80 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
83 static const struct inode_operations mqueue_dir_inode_operations;
84 static const struct file_operations mqueue_file_operations;
85 static struct super_operations mqueue_super_ops;
86 static void remove_notification(struct mqueue_inode_info *info);
88 static spinlock_t mq_lock;
89 static struct kmem_cache *mqueue_inode_cachep;
90 static struct vfsmount *mqueue_mnt;
92 static unsigned int queues_count;
93 static unsigned int queues_max = DFLT_QUEUESMAX;
94 static unsigned int msg_max = DFLT_MSGMAX;
95 static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
97 static struct ctl_table_header * mq_sysctl_table;
99 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
101 return container_of(inode, struct mqueue_inode_info, vfs_inode);
104 static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
105 struct mq_attr *attr)
109 inode = new_inode(sb);
111 inode->i_mode = mode;
112 inode->i_uid = current->fsuid;
113 inode->i_gid = current->fsgid;
115 inode->i_mtime = inode->i_ctime = inode->i_atime =
119 struct mqueue_inode_info *info;
120 struct task_struct *p = current;
121 struct user_struct *u = p->user;
122 unsigned long mq_bytes, mq_msg_tblsz;
124 inode->i_fop = &mqueue_file_operations;
125 inode->i_size = FILENT_SIZE;
126 /* mqueue specific info */
127 info = MQUEUE_I(inode);
128 spin_lock_init(&info->lock);
129 init_waitqueue_head(&info->wait_q);
130 INIT_LIST_HEAD(&info->e_wait_q[0].list);
131 INIT_LIST_HEAD(&info->e_wait_q[1].list);
132 info->messages = NULL;
133 info->notify_owner = NULL;
135 info->user = NULL; /* set when all is ok */
136 memset(&info->attr, 0, sizeof(info->attr));
137 info->attr.mq_maxmsg = DFLT_MSGMAX;
138 info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
140 info->attr.mq_maxmsg = attr->mq_maxmsg;
141 info->attr.mq_msgsize = attr->mq_msgsize;
143 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
144 mq_bytes = (mq_msg_tblsz +
145 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
148 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
149 u->mq_bytes + mq_bytes >
150 p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
151 spin_unlock(&mq_lock);
154 u->mq_bytes += mq_bytes;
155 spin_unlock(&mq_lock);
157 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
158 if (!info->messages) {
160 u->mq_bytes -= mq_bytes;
161 spin_unlock(&mq_lock);
165 info->user = get_uid(u);
166 } else if (S_ISDIR(mode)) {
168 /* Some things misbehave if size == 0 on a directory */
169 inode->i_size = 2 * DIRENT_SIZE;
170 inode->i_op = &mqueue_dir_inode_operations;
171 inode->i_fop = &simple_dir_operations;
176 make_bad_inode(inode);
181 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
185 sb->s_blocksize = PAGE_CACHE_SIZE;
186 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
187 sb->s_magic = MQUEUE_MAGIC;
188 sb->s_op = &mqueue_super_ops;
190 inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
194 sb->s_root = d_alloc_root(inode);
203 static int mqueue_get_sb(struct file_system_type *fs_type,
204 int flags, const char *dev_name,
205 void *data, struct vfsmount *mnt)
207 return get_sb_single(fs_type, flags, data, mqueue_fill_super, mnt);
210 static void init_once(struct kmem_cache *cachep, void *foo)
212 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
214 inode_init_once(&p->vfs_inode);
217 static struct inode *mqueue_alloc_inode(struct super_block *sb)
219 struct mqueue_inode_info *ei;
221 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
224 return &ei->vfs_inode;
227 static void mqueue_destroy_inode(struct inode *inode)
229 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
232 static void mqueue_delete_inode(struct inode *inode)
234 struct mqueue_inode_info *info;
235 struct user_struct *user;
236 unsigned long mq_bytes;
239 if (S_ISDIR(inode->i_mode)) {
243 info = MQUEUE_I(inode);
244 spin_lock(&info->lock);
245 for (i = 0; i < info->attr.mq_curmsgs; i++)
246 free_msg(info->messages[i]);
247 kfree(info->messages);
248 spin_unlock(&info->lock);
252 mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
253 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
257 user->mq_bytes -= mq_bytes;
259 spin_unlock(&mq_lock);
264 static int mqueue_create(struct inode *dir, struct dentry *dentry,
265 int mode, struct nameidata *nd)
268 struct mq_attr *attr = dentry->d_fsdata;
272 if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
277 spin_unlock(&mq_lock);
279 inode = mqueue_get_inode(dir->i_sb, mode, attr);
287 dir->i_size += DIRENT_SIZE;
288 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
290 d_instantiate(dentry, inode);
294 spin_unlock(&mq_lock);
298 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
300 struct inode *inode = dentry->d_inode;
302 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
303 dir->i_size -= DIRENT_SIZE;
310 * This is routine for system read from queue file.
311 * To avoid mess with doing here some sort of mq_receive we allow
312 * to read only queue size & notification info (the only values
313 * that are interesting from user point of view and aren't accessible
314 * through std routines)
316 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
317 size_t count, loff_t * off)
319 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
320 char buffer[FILENT_SIZE];
327 spin_lock(&info->lock);
328 snprintf(buffer, sizeof(buffer),
329 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
331 info->notify_owner ? info->notify.sigev_notify : 0,
332 (info->notify_owner &&
333 info->notify.sigev_notify == SIGEV_SIGNAL) ?
334 info->notify.sigev_signo : 0,
335 pid_nr_ns(info->notify_owner,
336 current->nsproxy->pid_ns));
337 spin_unlock(&info->lock);
338 buffer[sizeof(buffer)-1] = '\0';
339 slen = strlen(buffer)+1;
345 if (o + count > slen)
348 if (copy_to_user(u_data, buffer + o, count))
352 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
356 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
358 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
360 spin_lock(&info->lock);
361 if (task_tgid(current) == info->notify_owner)
362 remove_notification(info);
364 spin_unlock(&info->lock);
368 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
370 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
373 poll_wait(filp, &info->wait_q, poll_tab);
375 spin_lock(&info->lock);
376 if (info->attr.mq_curmsgs)
377 retval = POLLIN | POLLRDNORM;
379 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
380 retval |= POLLOUT | POLLWRNORM;
381 spin_unlock(&info->lock);
386 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
387 static void wq_add(struct mqueue_inode_info *info, int sr,
388 struct ext_wait_queue *ewp)
390 struct ext_wait_queue *walk;
394 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
395 if (walk->task->static_prio <= current->static_prio) {
396 list_add_tail(&ewp->list, &walk->list);
400 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
404 * Puts current task to sleep. Caller must hold queue lock. After return
408 static int wq_sleep(struct mqueue_inode_info *info, int sr,
409 long timeout, struct ext_wait_queue *ewp)
414 wq_add(info, sr, ewp);
417 set_current_state(TASK_INTERRUPTIBLE);
419 spin_unlock(&info->lock);
420 time = schedule_timeout(timeout);
422 while (ewp->state == STATE_PENDING)
425 if (ewp->state == STATE_READY) {
429 spin_lock(&info->lock);
430 if (ewp->state == STATE_READY) {
434 if (signal_pending(current)) {
435 retval = -ERESTARTSYS;
443 list_del(&ewp->list);
445 spin_unlock(&info->lock);
451 * Returns waiting task that should be serviced first or NULL if none exists
453 static struct ext_wait_queue *wq_get_first_waiter(
454 struct mqueue_inode_info *info, int sr)
456 struct list_head *ptr;
458 ptr = info->e_wait_q[sr].list.prev;
459 if (ptr == &info->e_wait_q[sr].list)
461 return list_entry(ptr, struct ext_wait_queue, list);
464 /* Auxiliary functions to manipulate messages' list */
465 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
469 k = info->attr.mq_curmsgs - 1;
470 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
471 info->messages[k + 1] = info->messages[k];
474 info->attr.mq_curmsgs++;
475 info->qsize += ptr->m_ts;
476 info->messages[k + 1] = ptr;
479 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
481 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
482 return info->messages[info->attr.mq_curmsgs];
485 static inline void set_cookie(struct sk_buff *skb, char code)
487 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
491 * The next function is only to split too long sys_mq_timedsend
493 static void __do_notify(struct mqueue_inode_info *info)
496 * invoked when there is registered process and there isn't process
497 * waiting synchronously for message AND state of queue changed from
498 * empty to not empty. Here we are sure that no one is waiting
500 if (info->notify_owner &&
501 info->attr.mq_curmsgs == 1) {
502 struct siginfo sig_i;
503 switch (info->notify.sigev_notify) {
509 sig_i.si_signo = info->notify.sigev_signo;
511 sig_i.si_code = SI_MESGQ;
512 sig_i.si_value = info->notify.sigev_value;
513 sig_i.si_pid = task_pid_vnr(current);
514 sig_i.si_uid = current->uid;
516 kill_pid_info(info->notify.sigev_signo,
517 &sig_i, info->notify_owner);
520 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
521 netlink_sendskb(info->notify_sock, info->notify_cookie);
524 /* after notification unregisters process */
525 put_pid(info->notify_owner);
526 info->notify_owner = NULL;
528 wake_up(&info->wait_q);
531 static long prepare_timeout(const struct timespec __user *u_arg)
533 struct timespec ts, nowts;
537 if (unlikely(copy_from_user(&ts, u_arg,
538 sizeof(struct timespec))))
541 if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
542 || ts.tv_nsec >= NSEC_PER_SEC))
544 nowts = CURRENT_TIME;
545 /* first subtract as jiffies can't be too big */
546 ts.tv_sec -= nowts.tv_sec;
547 if (ts.tv_nsec < nowts.tv_nsec) {
548 ts.tv_nsec += NSEC_PER_SEC;
551 ts.tv_nsec -= nowts.tv_nsec;
555 timeout = timespec_to_jiffies(&ts) + 1;
557 return MAX_SCHEDULE_TIMEOUT;
562 static void remove_notification(struct mqueue_inode_info *info)
564 if (info->notify_owner != NULL &&
565 info->notify.sigev_notify == SIGEV_THREAD) {
566 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
567 netlink_sendskb(info->notify_sock, info->notify_cookie);
569 put_pid(info->notify_owner);
570 info->notify_owner = NULL;
573 static int mq_attr_ok(struct mq_attr *attr)
575 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
577 if (capable(CAP_SYS_RESOURCE)) {
578 if (attr->mq_maxmsg > HARD_MSGMAX)
581 if (attr->mq_maxmsg > msg_max ||
582 attr->mq_msgsize > msgsize_max)
585 /* check for overflow */
586 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
588 if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
589 (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
590 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
596 * Invoked when creating a new queue via sys_mq_open
598 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
599 int oflag, mode_t mode, struct mq_attr __user *u_attr)
606 if (copy_from_user(&attr, u_attr, sizeof(attr)))
609 if (!mq_attr_ok(&attr))
611 /* store for use during create */
612 dentry->d_fsdata = &attr;
615 mode &= ~current->fs->umask;
616 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
617 dentry->d_fsdata = NULL;
621 return dentry_open(dentry, mqueue_mnt, oflag);
629 /* Opens existing queue */
630 static struct file *do_open(struct dentry *dentry, int oflag)
632 static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
633 MAY_READ | MAY_WRITE };
635 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
638 return ERR_PTR(-EINVAL);
641 if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
644 return ERR_PTR(-EACCES);
647 return dentry_open(dentry, mqueue_mnt, oflag);
650 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
651 struct mq_attr __user *u_attr)
653 struct dentry *dentry;
658 error = audit_mq_open(oflag, mode, u_attr);
662 if (IS_ERR(name = getname(u_name)))
663 return PTR_ERR(name);
665 fd = get_unused_fd();
669 mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
670 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
671 if (IS_ERR(dentry)) {
672 error = PTR_ERR(dentry);
677 if (oflag & O_CREAT) {
678 if (dentry->d_inode) { /* entry already exists */
679 audit_inode(name, dentry->d_inode);
683 filp = do_open(dentry, oflag);
685 filp = do_create(mqueue_mnt->mnt_root, dentry,
686 oflag, mode, u_attr);
690 if (!dentry->d_inode)
692 audit_inode(name, dentry->d_inode);
693 filp = do_open(dentry, oflag);
697 error = PTR_ERR(filp);
701 set_close_on_exec(fd, 1);
702 fd_install(fd, filp);
713 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
719 asmlinkage long sys_mq_unlink(const char __user *u_name)
723 struct dentry *dentry;
724 struct inode *inode = NULL;
726 name = getname(u_name);
728 return PTR_ERR(name);
730 mutex_lock_nested(&mqueue_mnt->mnt_root->d_inode->i_mutex,
732 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
733 if (IS_ERR(dentry)) {
734 err = PTR_ERR(dentry);
738 if (!dentry->d_inode) {
743 inode = dentry->d_inode;
745 atomic_inc(&inode->i_count);
747 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
752 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
760 /* Pipelined send and receive functions.
762 * If a receiver finds no waiting message, then it registers itself in the
763 * list of waiting receivers. A sender checks that list before adding the new
764 * message into the message array. If there is a waiting receiver, then it
765 * bypasses the message array and directly hands the message over to the
767 * The receiver accepts the message and returns without grabbing the queue
768 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
769 * are necessary. The same algorithm is used for sysv semaphores, see
770 * ipc/sem.c for more details.
772 * The same algorithm is used for senders.
775 /* pipelined_send() - send a message directly to the task waiting in
776 * sys_mq_timedreceive() (without inserting message into a queue).
778 static inline void pipelined_send(struct mqueue_inode_info *info,
779 struct msg_msg *message,
780 struct ext_wait_queue *receiver)
782 receiver->msg = message;
783 list_del(&receiver->list);
784 receiver->state = STATE_PENDING;
785 wake_up_process(receiver->task);
787 receiver->state = STATE_READY;
790 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
791 * gets its message and put to the queue (we have one free place for sure). */
792 static inline void pipelined_receive(struct mqueue_inode_info *info)
794 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
798 wake_up_interruptible(&info->wait_q);
801 msg_insert(sender->msg, info);
802 list_del(&sender->list);
803 sender->state = STATE_PENDING;
804 wake_up_process(sender->task);
806 sender->state = STATE_READY;
809 asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
810 size_t msg_len, unsigned int msg_prio,
811 const struct timespec __user *u_abs_timeout)
815 struct ext_wait_queue wait;
816 struct ext_wait_queue *receiver;
817 struct msg_msg *msg_ptr;
818 struct mqueue_inode_info *info;
822 ret = audit_mq_timedsend(mqdes, msg_len, msg_prio, u_abs_timeout);
826 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
829 timeout = prepare_timeout(u_abs_timeout);
836 inode = filp->f_path.dentry->d_inode;
837 if (unlikely(filp->f_op != &mqueue_file_operations))
839 info = MQUEUE_I(inode);
840 audit_inode(NULL, inode);
842 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
845 if (unlikely(msg_len > info->attr.mq_msgsize)) {
850 /* First try to allocate memory, before doing anything with
851 * existing queues. */
852 msg_ptr = load_msg(u_msg_ptr, msg_len);
853 if (IS_ERR(msg_ptr)) {
854 ret = PTR_ERR(msg_ptr);
857 msg_ptr->m_ts = msg_len;
858 msg_ptr->m_type = msg_prio;
860 spin_lock(&info->lock);
862 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
863 if (filp->f_flags & O_NONBLOCK) {
864 spin_unlock(&info->lock);
866 } else if (unlikely(timeout < 0)) {
867 spin_unlock(&info->lock);
871 wait.msg = (void *) msg_ptr;
872 wait.state = STATE_NONE;
873 ret = wq_sleep(info, SEND, timeout, &wait);
878 receiver = wq_get_first_waiter(info, RECV);
880 pipelined_send(info, msg_ptr, receiver);
882 /* adds message to the queue */
883 msg_insert(msg_ptr, info);
886 inode->i_atime = inode->i_mtime = inode->i_ctime =
888 spin_unlock(&info->lock);
897 asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
898 size_t msg_len, unsigned int __user *u_msg_prio,
899 const struct timespec __user *u_abs_timeout)
903 struct msg_msg *msg_ptr;
906 struct mqueue_inode_info *info;
907 struct ext_wait_queue wait;
909 ret = audit_mq_timedreceive(mqdes, msg_len, u_msg_prio, u_abs_timeout);
913 timeout = prepare_timeout(u_abs_timeout);
920 inode = filp->f_path.dentry->d_inode;
921 if (unlikely(filp->f_op != &mqueue_file_operations))
923 info = MQUEUE_I(inode);
924 audit_inode(NULL, inode);
926 if (unlikely(!(filp->f_mode & FMODE_READ)))
929 /* checks if buffer is big enough */
930 if (unlikely(msg_len < info->attr.mq_msgsize)) {
935 spin_lock(&info->lock);
936 if (info->attr.mq_curmsgs == 0) {
937 if (filp->f_flags & O_NONBLOCK) {
938 spin_unlock(&info->lock);
941 } else if (unlikely(timeout < 0)) {
942 spin_unlock(&info->lock);
947 wait.state = STATE_NONE;
948 ret = wq_sleep(info, RECV, timeout, &wait);
952 msg_ptr = msg_get(info);
954 inode->i_atime = inode->i_mtime = inode->i_ctime =
957 /* There is now free space in queue. */
958 pipelined_receive(info);
959 spin_unlock(&info->lock);
965 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
966 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
978 * Notes: the case when user wants us to deregister (with NULL as pointer)
979 * and he isn't currently owner of notification, will be silently discarded.
980 * It isn't explicitly defined in the POSIX.
982 asmlinkage long sys_mq_notify(mqd_t mqdes,
983 const struct sigevent __user *u_notification)
989 struct sigevent notification;
990 struct mqueue_inode_info *info;
993 ret = audit_mq_notify(mqdes, u_notification);
999 if (u_notification != NULL) {
1000 if (copy_from_user(¬ification, u_notification,
1001 sizeof(struct sigevent)))
1004 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1005 notification.sigev_notify != SIGEV_SIGNAL &&
1006 notification.sigev_notify != SIGEV_THREAD))
1008 if (notification.sigev_notify == SIGEV_SIGNAL &&
1009 !valid_signal(notification.sigev_signo)) {
1012 if (notification.sigev_notify == SIGEV_THREAD) {
1013 /* create the notify skb */
1014 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1019 if (copy_from_user(nc->data,
1020 notification.sigev_value.sival_ptr,
1021 NOTIFY_COOKIE_LEN)) {
1025 /* TODO: add a header? */
1026 skb_put(nc, NOTIFY_COOKIE_LEN);
1027 /* and attach it to the socket */
1029 filp = fget(notification.sigev_signo);
1033 sock = netlink_getsockbyfilp(filp);
1036 ret = PTR_ERR(sock);
1041 ret = netlink_attachskb(sock, nc, 0,
1042 MAX_SCHEDULE_TIMEOUT, NULL);
1058 inode = filp->f_path.dentry->d_inode;
1059 if (unlikely(filp->f_op != &mqueue_file_operations))
1061 info = MQUEUE_I(inode);
1064 spin_lock(&info->lock);
1065 if (u_notification == NULL) {
1066 if (info->notify_owner == task_tgid(current)) {
1067 remove_notification(info);
1068 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1070 } else if (info->notify_owner != NULL) {
1073 switch (notification.sigev_notify) {
1075 info->notify.sigev_notify = SIGEV_NONE;
1078 info->notify_sock = sock;
1079 info->notify_cookie = nc;
1082 info->notify.sigev_notify = SIGEV_THREAD;
1085 info->notify.sigev_signo = notification.sigev_signo;
1086 info->notify.sigev_value = notification.sigev_value;
1087 info->notify.sigev_notify = SIGEV_SIGNAL;
1091 info->notify_owner = get_pid(task_tgid(current));
1092 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1094 spin_unlock(&info->lock);
1099 netlink_detachskb(sock, nc);
1106 asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
1107 const struct mq_attr __user *u_mqstat,
1108 struct mq_attr __user *u_omqstat)
1111 struct mq_attr mqstat, omqstat;
1113 struct inode *inode;
1114 struct mqueue_inode_info *info;
1116 if (u_mqstat != NULL) {
1117 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1119 if (mqstat.mq_flags & (~O_NONBLOCK))
1128 inode = filp->f_path.dentry->d_inode;
1129 if (unlikely(filp->f_op != &mqueue_file_operations))
1131 info = MQUEUE_I(inode);
1133 spin_lock(&info->lock);
1135 omqstat = info->attr;
1136 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1138 ret = audit_mq_getsetattr(mqdes, &mqstat);
1141 if (mqstat.mq_flags & O_NONBLOCK)
1142 filp->f_flags |= O_NONBLOCK;
1144 filp->f_flags &= ~O_NONBLOCK;
1146 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1149 spin_unlock(&info->lock);
1152 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1153 sizeof(struct mq_attr)))
1162 static const struct inode_operations mqueue_dir_inode_operations = {
1163 .lookup = simple_lookup,
1164 .create = mqueue_create,
1165 .unlink = mqueue_unlink,
1168 static const struct file_operations mqueue_file_operations = {
1169 .flush = mqueue_flush_file,
1170 .poll = mqueue_poll_file,
1171 .read = mqueue_read_file,
1174 static struct super_operations mqueue_super_ops = {
1175 .alloc_inode = mqueue_alloc_inode,
1176 .destroy_inode = mqueue_destroy_inode,
1177 .statfs = simple_statfs,
1178 .delete_inode = mqueue_delete_inode,
1179 .drop_inode = generic_delete_inode,
1182 static struct file_system_type mqueue_fs_type = {
1184 .get_sb = mqueue_get_sb,
1185 .kill_sb = kill_litter_super,
1188 static int msg_max_limit_min = DFLT_MSGMAX;
1189 static int msg_max_limit_max = HARD_MSGMAX;
1191 static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
1192 static int msg_maxsize_limit_max = INT_MAX;
1194 static ctl_table mq_sysctls[] = {
1196 .procname = "queues_max",
1197 .data = &queues_max,
1198 .maxlen = sizeof(int),
1200 .proc_handler = &proc_dointvec,
1203 .procname = "msg_max",
1205 .maxlen = sizeof(int),
1207 .proc_handler = &proc_dointvec_minmax,
1208 .extra1 = &msg_max_limit_min,
1209 .extra2 = &msg_max_limit_max,
1212 .procname = "msgsize_max",
1213 .data = &msgsize_max,
1214 .maxlen = sizeof(int),
1216 .proc_handler = &proc_dointvec_minmax,
1217 .extra1 = &msg_maxsize_limit_min,
1218 .extra2 = &msg_maxsize_limit_max,
1223 static ctl_table mq_sysctl_dir[] = {
1225 .procname = "mqueue",
1227 .child = mq_sysctls,
1232 static ctl_table mq_sysctl_root[] = {
1237 .child = mq_sysctl_dir,
1242 static int __init init_mqueue_fs(void)
1246 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1247 sizeof(struct mqueue_inode_info), 0,
1248 SLAB_HWCACHE_ALIGN, init_once);
1249 if (mqueue_inode_cachep == NULL)
1252 /* ignore failues - they are not fatal */
1253 mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
1255 error = register_filesystem(&mqueue_fs_type);
1259 if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
1260 error = PTR_ERR(mqueue_mnt);
1261 goto out_filesystem;
1264 /* internal initialization - not common for vfs */
1266 spin_lock_init(&mq_lock);
1271 unregister_filesystem(&mqueue_fs_type);
1273 if (mq_sysctl_table)
1274 unregister_sysctl_table(mq_sysctl_table);
1275 kmem_cache_destroy(mqueue_inode_cachep);
1279 __initcall(init_mqueue_fs);