2 * POSIX message queues filesystem for Linux.
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (wrona@mat.uni.torun.pl)
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
11 * This file is released under the GPL.
14 #include <linux/init.h>
15 #include <linux/pagemap.h>
16 #include <linux/file.h>
17 #include <linux/mount.h>
18 #include <linux/namei.h>
19 #include <linux/sysctl.h>
20 #include <linux/poll.h>
21 #include <linux/mqueue.h>
22 #include <linux/msg.h>
23 #include <linux/skbuff.h>
24 #include <linux/netlink.h>
28 #define MQUEUE_MAGIC 0x19800202
29 #define DIRENT_SIZE 20
30 #define FILENT_SIZE 80
36 #define STATE_PENDING 1
41 #define CTL_QUEUESMAX 2
43 #define CTL_MSGSIZEMAX 4
46 #define DFLT_QUEUESMAX 256 /* max number of message queues */
47 #define DFLT_MSGMAX 10 /* max number of messages in each queue */
48 #define HARD_MSGMAX (131072/sizeof(void*))
49 #define DFLT_MSGSIZEMAX 8192 /* max message size */
51 #define NOTIFY_COOKIE_LEN 32
53 struct ext_wait_queue { /* queue of sleeping tasks */
54 struct task_struct *task;
55 struct list_head list;
56 struct msg_msg *msg; /* ptr of loaded message */
57 int state; /* one of STATE_* values */
60 struct mqueue_inode_info {
62 struct inode vfs_inode;
63 wait_queue_head_t wait_q;
65 struct msg_msg **messages;
68 struct sigevent notify;
70 struct user_struct *user; /* user who created, for accouting */
71 struct sock *notify_sock;
72 struct sk_buff *notify_cookie;
74 /* for tasks waiting for free space and messages, respectively */
75 struct ext_wait_queue e_wait_q[2];
77 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
80 static struct inode_operations mqueue_dir_inode_operations;
81 static struct file_operations mqueue_file_operations;
82 static struct super_operations mqueue_super_ops;
83 static void remove_notification(struct mqueue_inode_info *info);
85 static spinlock_t mq_lock;
86 static kmem_cache_t *mqueue_inode_cachep;
87 static struct vfsmount *mqueue_mnt;
89 static unsigned int queues_count;
90 static unsigned int queues_max = DFLT_QUEUESMAX;
91 static unsigned int msg_max = DFLT_MSGMAX;
92 static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
94 static struct ctl_table_header * mq_sysctl_table;
96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
98 return container_of(inode, struct mqueue_inode_info, vfs_inode);
101 static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
102 struct mq_attr *attr)
106 inode = new_inode(sb);
108 inode->i_mode = mode;
109 inode->i_uid = current->fsuid;
110 inode->i_gid = current->fsgid;
111 inode->i_blksize = PAGE_CACHE_SIZE;
113 inode->i_mtime = inode->i_ctime = inode->i_atime =
117 struct mqueue_inode_info *info;
118 struct task_struct *p = current;
119 struct user_struct *u = p->user;
120 unsigned long mq_bytes, mq_msg_tblsz;
122 inode->i_fop = &mqueue_file_operations;
123 inode->i_size = FILENT_SIZE;
124 /* mqueue specific info */
125 info = MQUEUE_I(inode);
126 spin_lock_init(&info->lock);
127 init_waitqueue_head(&info->wait_q);
128 INIT_LIST_HEAD(&info->e_wait_q[0].list);
129 INIT_LIST_HEAD(&info->e_wait_q[1].list);
130 info->messages = NULL;
131 info->notify_owner = 0;
133 info->user = NULL; /* set when all is ok */
134 memset(&info->attr, 0, sizeof(info->attr));
135 info->attr.mq_maxmsg = DFLT_MSGMAX;
136 info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
138 info->attr.mq_maxmsg = attr->mq_maxmsg;
139 info->attr.mq_msgsize = attr->mq_msgsize;
141 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
142 mq_bytes = (mq_msg_tblsz +
143 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
146 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
147 u->mq_bytes + mq_bytes >
148 p->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
149 spin_unlock(&mq_lock);
152 u->mq_bytes += mq_bytes;
153 spin_unlock(&mq_lock);
155 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
156 if (!info->messages) {
158 u->mq_bytes -= mq_bytes;
159 spin_unlock(&mq_lock);
163 info->user = get_uid(u);
164 } else if (S_ISDIR(mode)) {
166 /* Some things misbehave if size == 0 on a directory */
167 inode->i_size = 2 * DIRENT_SIZE;
168 inode->i_op = &mqueue_dir_inode_operations;
169 inode->i_fop = &simple_dir_operations;
174 make_bad_inode(inode);
179 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
183 sb->s_blocksize = PAGE_CACHE_SIZE;
184 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
185 sb->s_magic = MQUEUE_MAGIC;
186 sb->s_op = &mqueue_super_ops;
188 inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
192 sb->s_root = d_alloc_root(inode);
201 static struct super_block *mqueue_get_sb(struct file_system_type *fs_type,
202 int flags, const char *dev_name,
205 return get_sb_single(fs_type, flags, data, mqueue_fill_super);
208 static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags)
210 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
212 if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
213 SLAB_CTOR_CONSTRUCTOR)
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, SLAB_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_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,
336 spin_unlock(&info->lock);
337 buffer[sizeof(buffer)-1] = '\0';
338 slen = strlen(buffer)+1;
344 if (o + count > slen)
347 if (copy_to_user(u_data, buffer + o, count))
351 filp->f_dentry->d_inode->i_atime = filp->f_dentry->d_inode->i_ctime = CURRENT_TIME;
355 static int mqueue_flush_file(struct file *filp)
357 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
359 spin_lock(&info->lock);
360 if (current->tgid == info->notify_owner)
361 remove_notification(info);
363 spin_unlock(&info->lock);
367 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
369 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
372 poll_wait(filp, &info->wait_q, poll_tab);
374 spin_lock(&info->lock);
375 if (info->attr.mq_curmsgs)
376 retval = POLLIN | POLLRDNORM;
378 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
379 retval |= POLLOUT | POLLWRNORM;
380 spin_unlock(&info->lock);
385 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
386 static void wq_add(struct mqueue_inode_info *info, int sr,
387 struct ext_wait_queue *ewp)
389 struct ext_wait_queue *walk;
393 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
394 if (walk->task->static_prio <= current->static_prio) {
395 list_add_tail(&ewp->list, &walk->list);
399 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
403 * Puts current task to sleep. Caller must hold queue lock. After return
407 static int wq_sleep(struct mqueue_inode_info *info, int sr,
408 long timeout, struct ext_wait_queue *ewp)
413 wq_add(info, sr, ewp);
416 set_current_state(TASK_INTERRUPTIBLE);
418 spin_unlock(&info->lock);
419 time = schedule_timeout(timeout);
421 while (ewp->state == STATE_PENDING)
424 if (ewp->state == STATE_READY) {
428 spin_lock(&info->lock);
429 if (ewp->state == STATE_READY) {
433 if (signal_pending(current)) {
434 retval = -ERESTARTSYS;
442 list_del(&ewp->list);
444 spin_unlock(&info->lock);
450 * Returns waiting task that should be serviced first or NULL if none exists
452 static struct ext_wait_queue *wq_get_first_waiter(
453 struct mqueue_inode_info *info, int sr)
455 struct list_head *ptr;
457 ptr = info->e_wait_q[sr].list.prev;
458 if (ptr == &info->e_wait_q[sr].list)
460 return list_entry(ptr, struct ext_wait_queue, list);
463 /* Auxiliary functions to manipulate messages' list */
464 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
468 k = info->attr.mq_curmsgs - 1;
469 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
470 info->messages[k + 1] = info->messages[k];
473 info->attr.mq_curmsgs++;
474 info->qsize += ptr->m_ts;
475 info->messages[k + 1] = ptr;
478 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
480 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
481 return info->messages[info->attr.mq_curmsgs];
484 static inline void set_cookie(struct sk_buff *skb, char code)
486 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
490 * The next function is only to split too long sys_mq_timedsend
492 static void __do_notify(struct mqueue_inode_info *info)
495 * invoked when there is registered process and there isn't process
496 * waiting synchronously for message AND state of queue changed from
497 * empty to not empty. Here we are sure that no one is waiting
499 if (info->notify_owner &&
500 info->attr.mq_curmsgs == 1) {
501 struct siginfo sig_i;
502 switch (info->notify.sigev_notify) {
508 sig_i.si_signo = info->notify.sigev_signo;
510 sig_i.si_code = SI_MESGQ;
511 sig_i.si_value = info->notify.sigev_value;
512 sig_i.si_pid = current->tgid;
513 sig_i.si_uid = current->uid;
515 kill_proc_info(info->notify.sigev_signo,
516 &sig_i, info->notify_owner);
519 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
520 netlink_sendskb(info->notify_sock,
521 info->notify_cookie, 0);
524 /* after notification unregisters process */
525 info->notify_owner = 0;
527 wake_up(&info->wait_q);
530 static long prepare_timeout(const struct timespec __user *u_arg)
532 struct timespec ts, nowts;
536 if (unlikely(copy_from_user(&ts, u_arg,
537 sizeof(struct timespec))))
540 if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
541 || ts.tv_nsec >= NSEC_PER_SEC))
543 nowts = CURRENT_TIME;
544 /* first subtract as jiffies can't be too big */
545 ts.tv_sec -= nowts.tv_sec;
546 if (ts.tv_nsec < nowts.tv_nsec) {
547 ts.tv_nsec += NSEC_PER_SEC;
550 ts.tv_nsec -= nowts.tv_nsec;
554 timeout = timespec_to_jiffies(&ts) + 1;
556 return MAX_SCHEDULE_TIMEOUT;
561 static void remove_notification(struct mqueue_inode_info *info)
563 if (info->notify_owner != 0 &&
564 info->notify.sigev_notify == SIGEV_THREAD) {
565 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
566 netlink_sendskb(info->notify_sock, info->notify_cookie, 0);
568 info->notify_owner = 0;
571 static int mq_attr_ok(struct mq_attr *attr)
573 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
575 if (capable(CAP_SYS_RESOURCE)) {
576 if (attr->mq_maxmsg > HARD_MSGMAX)
579 if (attr->mq_maxmsg > msg_max ||
580 attr->mq_msgsize > msgsize_max)
583 /* check for overflow */
584 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
586 if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
587 (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
588 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
594 * Invoked when creating a new queue via sys_mq_open
596 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
597 int oflag, mode_t mode, struct mq_attr __user *u_attr)
603 if (u_attr != NULL) {
604 if (copy_from_user(&attr, u_attr, sizeof(attr)))
605 return ERR_PTR(-EFAULT);
606 if (!mq_attr_ok(&attr))
607 return ERR_PTR(-EINVAL);
608 /* store for use during create */
609 dentry->d_fsdata = &attr;
612 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
613 dentry->d_fsdata = NULL;
617 filp = dentry_open(dentry, mqueue_mnt, oflag);
624 /* Opens existing queue */
625 static struct file *do_open(struct dentry *dentry, int oflag)
627 static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
628 MAY_READ | MAY_WRITE };
631 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
632 return ERR_PTR(-EINVAL);
634 if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL))
635 return ERR_PTR(-EACCES);
637 filp = dentry_open(dentry, mqueue_mnt, oflag);
645 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
646 struct mq_attr __user *u_attr)
648 struct dentry *dentry;
653 if (IS_ERR(name = getname(u_name)))
654 return PTR_ERR(name);
656 fd = get_unused_fd();
660 down(&mqueue_mnt->mnt_root->d_inode->i_sem);
661 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
662 if (IS_ERR(dentry)) {
663 error = PTR_ERR(dentry);
668 if (oflag & O_CREAT) {
669 if (dentry->d_inode) { /* entry already exists */
670 filp = (oflag & O_EXCL) ? ERR_PTR(-EEXIST) :
671 do_open(dentry, oflag);
673 filp = do_create(mqueue_mnt->mnt_root, dentry,
674 oflag, mode, u_attr);
677 filp = (dentry->d_inode) ? do_open(dentry, oflag) :
683 error = PTR_ERR(filp);
687 set_close_on_exec(fd, 1);
688 fd_install(fd, filp);
697 up(&mqueue_mnt->mnt_root->d_inode->i_sem);
703 asmlinkage long sys_mq_unlink(const char __user *u_name)
707 struct dentry *dentry;
708 struct inode *inode = NULL;
710 name = getname(u_name);
712 return PTR_ERR(name);
714 down(&mqueue_mnt->mnt_root->d_inode->i_sem);
715 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
716 if (IS_ERR(dentry)) {
717 err = PTR_ERR(dentry);
721 if (!dentry->d_inode) {
726 inode = dentry->d_inode;
728 atomic_inc(&inode->i_count);
730 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
735 up(&mqueue_mnt->mnt_root->d_inode->i_sem);
743 /* Pipelined send and receive functions.
745 * If a receiver finds no waiting message, then it registers itself in the
746 * list of waiting receivers. A sender checks that list before adding the new
747 * message into the message array. If there is a waiting receiver, then it
748 * bypasses the message array and directly hands the message over to the
750 * The receiver accepts the message and returns without grabbing the queue
751 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
752 * are necessary. The same algorithm is used for sysv semaphores, see
753 * ipc/sem.c fore more details.
755 * The same algorithm is used for senders.
758 /* pipelined_send() - send a message directly to the task waiting in
759 * sys_mq_timedreceive() (without inserting message into a queue).
761 static inline void pipelined_send(struct mqueue_inode_info *info,
762 struct msg_msg *message,
763 struct ext_wait_queue *receiver)
765 receiver->msg = message;
766 list_del(&receiver->list);
767 receiver->state = STATE_PENDING;
768 wake_up_process(receiver->task);
770 receiver->state = STATE_READY;
773 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
774 * gets its message and put to the queue (we have one free place for sure). */
775 static inline void pipelined_receive(struct mqueue_inode_info *info)
777 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
781 wake_up_interruptible(&info->wait_q);
784 msg_insert(sender->msg, info);
785 list_del(&sender->list);
786 sender->state = STATE_PENDING;
787 wake_up_process(sender->task);
789 sender->state = STATE_READY;
792 asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
793 size_t msg_len, unsigned int msg_prio,
794 const struct timespec __user *u_abs_timeout)
798 struct ext_wait_queue wait;
799 struct ext_wait_queue *receiver;
800 struct msg_msg *msg_ptr;
801 struct mqueue_inode_info *info;
805 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
808 timeout = prepare_timeout(u_abs_timeout);
815 inode = filp->f_dentry->d_inode;
816 if (unlikely(filp->f_op != &mqueue_file_operations))
818 info = MQUEUE_I(inode);
820 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
823 if (unlikely(msg_len > info->attr.mq_msgsize)) {
828 /* First try to allocate memory, before doing anything with
829 * existing queues. */
830 msg_ptr = load_msg(u_msg_ptr, msg_len);
831 if (IS_ERR(msg_ptr)) {
832 ret = PTR_ERR(msg_ptr);
835 msg_ptr->m_ts = msg_len;
836 msg_ptr->m_type = msg_prio;
838 spin_lock(&info->lock);
840 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
841 if (filp->f_flags & O_NONBLOCK) {
842 spin_unlock(&info->lock);
844 } else if (unlikely(timeout < 0)) {
845 spin_unlock(&info->lock);
849 wait.msg = (void *) msg_ptr;
850 wait.state = STATE_NONE;
851 ret = wq_sleep(info, SEND, timeout, &wait);
856 receiver = wq_get_first_waiter(info, RECV);
858 pipelined_send(info, msg_ptr, receiver);
860 /* adds message to the queue */
861 msg_insert(msg_ptr, info);
864 inode->i_atime = inode->i_mtime = inode->i_ctime =
866 spin_unlock(&info->lock);
875 asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
876 size_t msg_len, unsigned int __user *u_msg_prio,
877 const struct timespec __user *u_abs_timeout)
881 struct msg_msg *msg_ptr;
884 struct mqueue_inode_info *info;
885 struct ext_wait_queue wait;
887 timeout = prepare_timeout(u_abs_timeout);
894 inode = filp->f_dentry->d_inode;
895 if (unlikely(filp->f_op != &mqueue_file_operations))
897 info = MQUEUE_I(inode);
899 if (unlikely(!(filp->f_mode & FMODE_READ)))
902 /* checks if buffer is big enough */
903 if (unlikely(msg_len < info->attr.mq_msgsize)) {
908 spin_lock(&info->lock);
909 if (info->attr.mq_curmsgs == 0) {
910 if (filp->f_flags & O_NONBLOCK) {
911 spin_unlock(&info->lock);
914 } else if (unlikely(timeout < 0)) {
915 spin_unlock(&info->lock);
920 wait.state = STATE_NONE;
921 ret = wq_sleep(info, RECV, timeout, &wait);
925 msg_ptr = msg_get(info);
927 inode->i_atime = inode->i_mtime = inode->i_ctime =
930 /* There is now free space in queue. */
931 pipelined_receive(info);
932 spin_unlock(&info->lock);
938 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
939 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
951 * Notes: the case when user wants us to deregister (with NULL as pointer)
952 * and he isn't currently owner of notification, will be silently discarded.
953 * It isn't explicitly defined in the POSIX.
955 asmlinkage long sys_mq_notify(mqd_t mqdes,
956 const struct sigevent __user *u_notification)
962 struct sigevent notification;
963 struct mqueue_inode_info *info;
968 if (u_notification != NULL) {
969 if (copy_from_user(¬ification, u_notification,
970 sizeof(struct sigevent)))
973 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
974 notification.sigev_notify != SIGEV_SIGNAL &&
975 notification.sigev_notify != SIGEV_THREAD))
977 if (notification.sigev_notify == SIGEV_SIGNAL &&
978 (notification.sigev_signo < 0 ||
979 notification.sigev_signo > _NSIG)) {
982 if (notification.sigev_notify == SIGEV_THREAD) {
983 /* create the notify skb */
984 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
989 if (copy_from_user(nc->data,
990 notification.sigev_value.sival_ptr,
991 NOTIFY_COOKIE_LEN)) {
995 /* TODO: add a header? */
996 skb_put(nc, NOTIFY_COOKIE_LEN);
997 /* and attach it to the socket */
999 filp = fget(notification.sigev_signo);
1003 sock = netlink_getsockbyfilp(filp);
1006 ret = PTR_ERR(sock);
1011 ret = netlink_attachskb(sock, nc, 0, MAX_SCHEDULE_TIMEOUT);
1027 inode = filp->f_dentry->d_inode;
1028 if (unlikely(filp->f_op != &mqueue_file_operations))
1030 info = MQUEUE_I(inode);
1033 spin_lock(&info->lock);
1034 if (u_notification == NULL) {
1035 if (info->notify_owner == current->tgid) {
1036 remove_notification(info);
1037 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1039 } else if (info->notify_owner != 0) {
1042 switch (notification.sigev_notify) {
1044 info->notify.sigev_notify = SIGEV_NONE;
1047 info->notify_sock = sock;
1048 info->notify_cookie = nc;
1051 info->notify.sigev_notify = SIGEV_THREAD;
1054 info->notify.sigev_signo = notification.sigev_signo;
1055 info->notify.sigev_value = notification.sigev_value;
1056 info->notify.sigev_notify = SIGEV_SIGNAL;
1059 info->notify_owner = current->tgid;
1060 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1062 spin_unlock(&info->lock);
1067 netlink_detachskb(sock, nc);
1074 asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
1075 const struct mq_attr __user *u_mqstat,
1076 struct mq_attr __user *u_omqstat)
1079 struct mq_attr mqstat, omqstat;
1081 struct inode *inode;
1082 struct mqueue_inode_info *info;
1084 if (u_mqstat != NULL) {
1085 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1087 if (mqstat.mq_flags & (~O_NONBLOCK))
1096 inode = filp->f_dentry->d_inode;
1097 if (unlikely(filp->f_op != &mqueue_file_operations))
1099 info = MQUEUE_I(inode);
1101 spin_lock(&info->lock);
1103 omqstat = info->attr;
1104 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1106 if (mqstat.mq_flags & O_NONBLOCK)
1107 filp->f_flags |= O_NONBLOCK;
1109 filp->f_flags &= ~O_NONBLOCK;
1111 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1114 spin_unlock(&info->lock);
1117 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1118 sizeof(struct mq_attr)))
1127 static struct inode_operations mqueue_dir_inode_operations = {
1128 .lookup = simple_lookup,
1129 .create = mqueue_create,
1130 .unlink = mqueue_unlink,
1133 static struct file_operations mqueue_file_operations = {
1134 .flush = mqueue_flush_file,
1135 .poll = mqueue_poll_file,
1136 .read = mqueue_read_file,
1139 static struct super_operations mqueue_super_ops = {
1140 .alloc_inode = mqueue_alloc_inode,
1141 .destroy_inode = mqueue_destroy_inode,
1142 .statfs = simple_statfs,
1143 .delete_inode = mqueue_delete_inode,
1144 .drop_inode = generic_delete_inode,
1147 static struct file_system_type mqueue_fs_type = {
1149 .get_sb = mqueue_get_sb,
1150 .kill_sb = kill_litter_super,
1153 static int msg_max_limit_min = DFLT_MSGMAX;
1154 static int msg_max_limit_max = HARD_MSGMAX;
1156 static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
1157 static int msg_maxsize_limit_max = INT_MAX;
1159 static ctl_table mq_sysctls[] = {
1161 .ctl_name = CTL_QUEUESMAX,
1162 .procname = "queues_max",
1163 .data = &queues_max,
1164 .maxlen = sizeof(int),
1166 .proc_handler = &proc_dointvec,
1169 .ctl_name = CTL_MSGMAX,
1170 .procname = "msg_max",
1172 .maxlen = sizeof(int),
1174 .proc_handler = &proc_dointvec_minmax,
1175 .extra1 = &msg_max_limit_min,
1176 .extra2 = &msg_max_limit_max,
1179 .ctl_name = CTL_MSGSIZEMAX,
1180 .procname = "msgsize_max",
1181 .data = &msgsize_max,
1182 .maxlen = sizeof(int),
1184 .proc_handler = &proc_dointvec_minmax,
1185 .extra1 = &msg_maxsize_limit_min,
1186 .extra2 = &msg_maxsize_limit_max,
1191 static ctl_table mq_sysctl_dir[] = {
1193 .ctl_name = FS_MQUEUE,
1194 .procname = "mqueue",
1196 .child = mq_sysctls,
1201 static ctl_table mq_sysctl_root[] = {
1206 .child = mq_sysctl_dir,
1211 static int __init init_mqueue_fs(void)
1215 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1216 sizeof(struct mqueue_inode_info), 0,
1217 SLAB_HWCACHE_ALIGN, init_once, NULL);
1218 if (mqueue_inode_cachep == NULL)
1221 mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0);
1222 if (!mq_sysctl_table) {
1227 error = register_filesystem(&mqueue_fs_type);
1231 if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
1232 error = PTR_ERR(mqueue_mnt);
1233 goto out_filesystem;
1236 /* internal initialization - not common for vfs */
1238 spin_lock_init(&mq_lock);
1243 unregister_filesystem(&mqueue_fs_type);
1245 unregister_sysctl_table(mq_sysctl_table);
1247 if (kmem_cache_destroy(mqueue_inode_cachep)) {
1249 "mqueue_inode_cache: not all structures were freed\n");
1254 __initcall(init_mqueue_fs);