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>
35 #include <linux/user_namespace.h>
36 #include <linux/slab.h>
41 #define MQUEUE_MAGIC 0x19800202
42 #define DIRENT_SIZE 20
43 #define FILENT_SIZE 80
49 #define STATE_PENDING 1
52 struct ext_wait_queue { /* queue of sleeping tasks */
53 struct task_struct *task;
54 struct list_head list;
55 struct msg_msg *msg; /* ptr of loaded message */
56 int state; /* one of STATE_* values */
59 struct mqueue_inode_info {
61 struct inode vfs_inode;
62 wait_queue_head_t wait_q;
64 struct msg_msg **messages;
67 struct sigevent notify;
68 struct pid* notify_owner;
69 struct user_struct *user; /* user who created, for accounting */
70 struct sock *notify_sock;
71 struct sk_buff *notify_cookie;
73 /* for tasks waiting for free space and messages, respectively */
74 struct ext_wait_queue e_wait_q[2];
76 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
79 static const struct inode_operations mqueue_dir_inode_operations;
80 static const struct file_operations mqueue_file_operations;
81 static const struct super_operations mqueue_super_ops;
82 static void remove_notification(struct mqueue_inode_info *info);
84 static struct kmem_cache *mqueue_inode_cachep;
86 static struct ctl_table_header * mq_sysctl_table;
88 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
90 return container_of(inode, struct mqueue_inode_info, vfs_inode);
94 * This routine should be called with the mq_lock held.
96 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
98 return get_ipc_ns(inode->i_sb->s_fs_info);
101 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
103 struct ipc_namespace *ns;
106 ns = __get_ns_from_inode(inode);
107 spin_unlock(&mq_lock);
111 static struct inode *mqueue_get_inode(struct super_block *sb,
112 struct ipc_namespace *ipc_ns, umode_t mode,
113 struct mq_attr *attr)
115 struct user_struct *u = current_user();
119 inode = new_inode(sb);
123 inode->i_ino = get_next_ino();
124 inode->i_mode = mode;
125 inode->i_uid = current_fsuid();
126 inode->i_gid = current_fsgid();
127 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
130 struct mqueue_inode_info *info;
131 struct task_struct *p = current;
132 unsigned long mq_bytes, mq_msg_tblsz;
134 inode->i_fop = &mqueue_file_operations;
135 inode->i_size = FILENT_SIZE;
136 /* mqueue specific info */
137 info = MQUEUE_I(inode);
138 spin_lock_init(&info->lock);
139 init_waitqueue_head(&info->wait_q);
140 INIT_LIST_HEAD(&info->e_wait_q[0].list);
141 INIT_LIST_HEAD(&info->e_wait_q[1].list);
142 info->notify_owner = NULL;
144 info->user = NULL; /* set when all is ok */
145 memset(&info->attr, 0, sizeof(info->attr));
146 info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
147 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
149 info->attr.mq_maxmsg = attr->mq_maxmsg;
150 info->attr.mq_msgsize = attr->mq_msgsize;
152 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
153 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
157 mq_bytes = (mq_msg_tblsz +
158 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
161 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
162 u->mq_bytes + mq_bytes > task_rlimit(p, RLIMIT_MSGQUEUE)) {
163 spin_unlock(&mq_lock);
164 /* mqueue_evict_inode() releases info->messages */
168 u->mq_bytes += mq_bytes;
169 spin_unlock(&mq_lock);
172 info->user = get_uid(u);
173 } else if (S_ISDIR(mode)) {
175 /* Some things misbehave if size == 0 on a directory */
176 inode->i_size = 2 * DIRENT_SIZE;
177 inode->i_op = &mqueue_dir_inode_operations;
178 inode->i_fop = &simple_dir_operations;
188 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
191 struct ipc_namespace *ns = data;
194 sb->s_blocksize = PAGE_CACHE_SIZE;
195 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
196 sb->s_magic = MQUEUE_MAGIC;
197 sb->s_op = &mqueue_super_ops;
199 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
202 error = PTR_ERR(inode);
206 sb->s_root = d_alloc_root(inode);
218 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
219 int flags, const char *dev_name,
222 if (!(flags & MS_KERNMOUNT))
223 data = current->nsproxy->ipc_ns;
224 return mount_ns(fs_type, flags, data, mqueue_fill_super);
227 static void init_once(void *foo)
229 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
231 inode_init_once(&p->vfs_inode);
234 static struct inode *mqueue_alloc_inode(struct super_block *sb)
236 struct mqueue_inode_info *ei;
238 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
241 return &ei->vfs_inode;
244 static void mqueue_i_callback(struct rcu_head *head)
246 struct inode *inode = container_of(head, struct inode, i_rcu);
247 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
250 static void mqueue_destroy_inode(struct inode *inode)
252 call_rcu(&inode->i_rcu, mqueue_i_callback);
255 static void mqueue_evict_inode(struct inode *inode)
257 struct mqueue_inode_info *info;
258 struct user_struct *user;
259 unsigned long mq_bytes;
261 struct ipc_namespace *ipc_ns;
263 end_writeback(inode);
265 if (S_ISDIR(inode->i_mode))
268 ipc_ns = get_ns_from_inode(inode);
269 info = MQUEUE_I(inode);
270 spin_lock(&info->lock);
271 for (i = 0; i < info->attr.mq_curmsgs; i++)
272 free_msg(info->messages[i]);
273 kfree(info->messages);
274 spin_unlock(&info->lock);
276 /* Total amount of bytes accounted for the mqueue */
277 mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
278 + info->attr.mq_msgsize);
282 user->mq_bytes -= mq_bytes;
284 * get_ns_from_inode() ensures that the
285 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
286 * to which we now hold a reference, or it is NULL.
287 * We can't put it here under mq_lock, though.
290 ipc_ns->mq_queues_count--;
291 spin_unlock(&mq_lock);
298 static int mqueue_create(struct inode *dir, struct dentry *dentry,
299 umode_t mode, struct nameidata *nd)
302 struct mq_attr *attr = dentry->d_fsdata;
304 struct ipc_namespace *ipc_ns;
307 ipc_ns = __get_ns_from_inode(dir);
312 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
313 !capable(CAP_SYS_RESOURCE)) {
317 ipc_ns->mq_queues_count++;
318 spin_unlock(&mq_lock);
320 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
322 error = PTR_ERR(inode);
324 ipc_ns->mq_queues_count--;
329 dir->i_size += DIRENT_SIZE;
330 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
332 d_instantiate(dentry, inode);
336 spin_unlock(&mq_lock);
342 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
344 struct inode *inode = dentry->d_inode;
346 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
347 dir->i_size -= DIRENT_SIZE;
354 * This is routine for system read from queue file.
355 * To avoid mess with doing here some sort of mq_receive we allow
356 * to read only queue size & notification info (the only values
357 * that are interesting from user point of view and aren't accessible
358 * through std routines)
360 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
361 size_t count, loff_t *off)
363 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
364 char buffer[FILENT_SIZE];
367 spin_lock(&info->lock);
368 snprintf(buffer, sizeof(buffer),
369 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
371 info->notify_owner ? info->notify.sigev_notify : 0,
372 (info->notify_owner &&
373 info->notify.sigev_notify == SIGEV_SIGNAL) ?
374 info->notify.sigev_signo : 0,
375 pid_vnr(info->notify_owner));
376 spin_unlock(&info->lock);
377 buffer[sizeof(buffer)-1] = '\0';
379 ret = simple_read_from_buffer(u_data, count, off, buffer,
384 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
388 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
390 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
392 spin_lock(&info->lock);
393 if (task_tgid(current) == info->notify_owner)
394 remove_notification(info);
396 spin_unlock(&info->lock);
400 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
402 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
405 poll_wait(filp, &info->wait_q, poll_tab);
407 spin_lock(&info->lock);
408 if (info->attr.mq_curmsgs)
409 retval = POLLIN | POLLRDNORM;
411 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
412 retval |= POLLOUT | POLLWRNORM;
413 spin_unlock(&info->lock);
418 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
419 static void wq_add(struct mqueue_inode_info *info, int sr,
420 struct ext_wait_queue *ewp)
422 struct ext_wait_queue *walk;
426 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
427 if (walk->task->static_prio <= current->static_prio) {
428 list_add_tail(&ewp->list, &walk->list);
432 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
436 * Puts current task to sleep. Caller must hold queue lock. After return
440 static int wq_sleep(struct mqueue_inode_info *info, int sr,
441 ktime_t *timeout, struct ext_wait_queue *ewp)
446 wq_add(info, sr, ewp);
449 set_current_state(TASK_INTERRUPTIBLE);
451 spin_unlock(&info->lock);
452 time = schedule_hrtimeout_range_clock(timeout, 0,
453 HRTIMER_MODE_ABS, CLOCK_REALTIME);
455 while (ewp->state == STATE_PENDING)
458 if (ewp->state == STATE_READY) {
462 spin_lock(&info->lock);
463 if (ewp->state == STATE_READY) {
467 if (signal_pending(current)) {
468 retval = -ERESTARTSYS;
476 list_del(&ewp->list);
478 spin_unlock(&info->lock);
484 * Returns waiting task that should be serviced first or NULL if none exists
486 static struct ext_wait_queue *wq_get_first_waiter(
487 struct mqueue_inode_info *info, int sr)
489 struct list_head *ptr;
491 ptr = info->e_wait_q[sr].list.prev;
492 if (ptr == &info->e_wait_q[sr].list)
494 return list_entry(ptr, struct ext_wait_queue, list);
497 /* Auxiliary functions to manipulate messages' list */
498 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
502 k = info->attr.mq_curmsgs - 1;
503 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
504 info->messages[k + 1] = info->messages[k];
507 info->attr.mq_curmsgs++;
508 info->qsize += ptr->m_ts;
509 info->messages[k + 1] = ptr;
512 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
514 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
515 return info->messages[info->attr.mq_curmsgs];
518 static inline void set_cookie(struct sk_buff *skb, char code)
520 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
524 * The next function is only to split too long sys_mq_timedsend
526 static void __do_notify(struct mqueue_inode_info *info)
529 * invoked when there is registered process and there isn't process
530 * waiting synchronously for message AND state of queue changed from
531 * empty to not empty. Here we are sure that no one is waiting
533 if (info->notify_owner &&
534 info->attr.mq_curmsgs == 1) {
535 struct siginfo sig_i;
536 switch (info->notify.sigev_notify) {
542 sig_i.si_signo = info->notify.sigev_signo;
544 sig_i.si_code = SI_MESGQ;
545 sig_i.si_value = info->notify.sigev_value;
546 /* map current pid/uid into info->owner's namespaces */
548 sig_i.si_pid = task_tgid_nr_ns(current,
549 ns_of_pid(info->notify_owner));
550 sig_i.si_uid = user_ns_map_uid(info->user->user_ns,
551 current_cred(), current_uid());
554 kill_pid_info(info->notify.sigev_signo,
555 &sig_i, info->notify_owner);
558 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
559 netlink_sendskb(info->notify_sock, info->notify_cookie);
562 /* after notification unregisters process */
563 put_pid(info->notify_owner);
564 info->notify_owner = NULL;
566 wake_up(&info->wait_q);
569 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
570 ktime_t *expires, struct timespec *ts)
572 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
574 if (!timespec_valid(ts))
577 *expires = timespec_to_ktime(*ts);
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 + 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, umode_t mode,
619 struct mq_attr *attr)
621 const struct cred *cred = current_cred();
626 if (!mq_attr_ok(ipc_ns, attr)) {
630 /* store for use during create */
631 dentry->d_fsdata = attr;
634 mode &= ~current_umask();
635 ret = mnt_want_write(ipc_ns->mq_mnt);
638 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
639 dentry->d_fsdata = NULL;
643 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
645 * dentry_open() took a persistent mnt_want_write(),
646 * so we can now drop this one.
648 mnt_drop_write(ipc_ns->mq_mnt);
652 mnt_drop_write(ipc_ns->mq_mnt);
655 mntput(ipc_ns->mq_mnt);
659 /* Opens existing queue */
660 static struct file *do_open(struct ipc_namespace *ipc_ns,
661 struct dentry *dentry, int oflag)
664 const struct cred *cred = current_cred();
666 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
667 MAY_READ | MAY_WRITE };
669 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
674 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
679 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
683 mntput(ipc_ns->mq_mnt);
687 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
688 struct mq_attr __user *, u_attr)
690 struct dentry *dentry;
695 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
697 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
700 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
702 if (IS_ERR(name = getname(u_name)))
703 return PTR_ERR(name);
705 fd = get_unused_fd_flags(O_CLOEXEC);
709 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
710 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
711 if (IS_ERR(dentry)) {
712 error = PTR_ERR(dentry);
715 mntget(ipc_ns->mq_mnt);
717 if (oflag & O_CREAT) {
718 if (dentry->d_inode) { /* entry already exists */
719 audit_inode(name, dentry);
720 if (oflag & O_EXCL) {
724 filp = do_open(ipc_ns, dentry, oflag);
726 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
728 u_attr ? &attr : NULL);
731 if (!dentry->d_inode) {
735 audit_inode(name, dentry);
736 filp = do_open(ipc_ns, dentry, oflag);
740 error = PTR_ERR(filp);
744 fd_install(fd, filp);
749 mntput(ipc_ns->mq_mnt);
754 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
760 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
764 struct dentry *dentry;
765 struct inode *inode = NULL;
766 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
768 name = getname(u_name);
770 return PTR_ERR(name);
772 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
774 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
775 if (IS_ERR(dentry)) {
776 err = PTR_ERR(dentry);
780 if (!dentry->d_inode) {
785 inode = dentry->d_inode;
788 err = mnt_want_write(ipc_ns->mq_mnt);
791 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
792 mnt_drop_write(ipc_ns->mq_mnt);
797 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
805 /* Pipelined send and receive functions.
807 * If a receiver finds no waiting message, then it registers itself in the
808 * list of waiting receivers. A sender checks that list before adding the new
809 * message into the message array. If there is a waiting receiver, then it
810 * bypasses the message array and directly hands the message over to the
812 * The receiver accepts the message and returns without grabbing the queue
813 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
814 * are necessary. The same algorithm is used for sysv semaphores, see
815 * ipc/sem.c for more details.
817 * The same algorithm is used for senders.
820 /* pipelined_send() - send a message directly to the task waiting in
821 * sys_mq_timedreceive() (without inserting message into a queue).
823 static inline void pipelined_send(struct mqueue_inode_info *info,
824 struct msg_msg *message,
825 struct ext_wait_queue *receiver)
827 receiver->msg = message;
828 list_del(&receiver->list);
829 receiver->state = STATE_PENDING;
830 wake_up_process(receiver->task);
832 receiver->state = STATE_READY;
835 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
836 * gets its message and put to the queue (we have one free place for sure). */
837 static inline void pipelined_receive(struct mqueue_inode_info *info)
839 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
843 wake_up_interruptible(&info->wait_q);
846 msg_insert(sender->msg, info);
847 list_del(&sender->list);
848 sender->state = STATE_PENDING;
849 wake_up_process(sender->task);
851 sender->state = STATE_READY;
854 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
855 size_t, msg_len, unsigned int, msg_prio,
856 const struct timespec __user *, u_abs_timeout)
860 struct ext_wait_queue wait;
861 struct ext_wait_queue *receiver;
862 struct msg_msg *msg_ptr;
863 struct mqueue_inode_info *info;
864 ktime_t expires, *timeout = NULL;
869 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
875 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
878 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
881 if (unlikely(!filp)) {
886 inode = filp->f_path.dentry->d_inode;
887 if (unlikely(filp->f_op != &mqueue_file_operations)) {
891 info = MQUEUE_I(inode);
892 audit_inode(NULL, filp->f_path.dentry);
894 if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
899 if (unlikely(msg_len > info->attr.mq_msgsize)) {
904 /* First try to allocate memory, before doing anything with
905 * existing queues. */
906 msg_ptr = load_msg(u_msg_ptr, msg_len);
907 if (IS_ERR(msg_ptr)) {
908 ret = PTR_ERR(msg_ptr);
911 msg_ptr->m_ts = msg_len;
912 msg_ptr->m_type = msg_prio;
914 spin_lock(&info->lock);
916 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
917 if (filp->f_flags & O_NONBLOCK) {
918 spin_unlock(&info->lock);
922 wait.msg = (void *) msg_ptr;
923 wait.state = STATE_NONE;
924 ret = wq_sleep(info, SEND, timeout, &wait);
929 receiver = wq_get_first_waiter(info, RECV);
931 pipelined_send(info, msg_ptr, receiver);
933 /* adds message to the queue */
934 msg_insert(msg_ptr, info);
937 inode->i_atime = inode->i_mtime = inode->i_ctime =
939 spin_unlock(&info->lock);
948 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
949 size_t, msg_len, unsigned int __user *, u_msg_prio,
950 const struct timespec __user *, u_abs_timeout)
953 struct msg_msg *msg_ptr;
956 struct mqueue_inode_info *info;
957 struct ext_wait_queue wait;
958 ktime_t expires, *timeout = NULL;
962 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
968 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
971 if (unlikely(!filp)) {
976 inode = filp->f_path.dentry->d_inode;
977 if (unlikely(filp->f_op != &mqueue_file_operations)) {
981 info = MQUEUE_I(inode);
982 audit_inode(NULL, filp->f_path.dentry);
984 if (unlikely(!(filp->f_mode & FMODE_READ))) {
989 /* checks if buffer is big enough */
990 if (unlikely(msg_len < info->attr.mq_msgsize)) {
995 spin_lock(&info->lock);
996 if (info->attr.mq_curmsgs == 0) {
997 if (filp->f_flags & O_NONBLOCK) {
998 spin_unlock(&info->lock);
1001 wait.task = current;
1002 wait.state = STATE_NONE;
1003 ret = wq_sleep(info, RECV, timeout, &wait);
1007 msg_ptr = msg_get(info);
1009 inode->i_atime = inode->i_mtime = inode->i_ctime =
1012 /* There is now free space in queue. */
1013 pipelined_receive(info);
1014 spin_unlock(&info->lock);
1018 ret = msg_ptr->m_ts;
1020 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1021 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1033 * Notes: the case when user wants us to deregister (with NULL as pointer)
1034 * and he isn't currently owner of notification, will be silently discarded.
1035 * It isn't explicitly defined in the POSIX.
1037 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1038 const struct sigevent __user *, u_notification)
1043 struct inode *inode;
1044 struct sigevent notification;
1045 struct mqueue_inode_info *info;
1048 if (u_notification) {
1049 if (copy_from_user(¬ification, u_notification,
1050 sizeof(struct sigevent)))
1054 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1058 if (u_notification != NULL) {
1059 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1060 notification.sigev_notify != SIGEV_SIGNAL &&
1061 notification.sigev_notify != SIGEV_THREAD))
1063 if (notification.sigev_notify == SIGEV_SIGNAL &&
1064 !valid_signal(notification.sigev_signo)) {
1067 if (notification.sigev_notify == SIGEV_THREAD) {
1070 /* create the notify skb */
1071 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1076 if (copy_from_user(nc->data,
1077 notification.sigev_value.sival_ptr,
1078 NOTIFY_COOKIE_LEN)) {
1083 /* TODO: add a header? */
1084 skb_put(nc, NOTIFY_COOKIE_LEN);
1085 /* and attach it to the socket */
1087 filp = fget(notification.sigev_signo);
1092 sock = netlink_getsockbyfilp(filp);
1095 ret = PTR_ERR(sock);
1100 timeo = MAX_SCHEDULE_TIMEOUT;
1101 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1118 inode = filp->f_path.dentry->d_inode;
1119 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1123 info = MQUEUE_I(inode);
1126 spin_lock(&info->lock);
1127 if (u_notification == NULL) {
1128 if (info->notify_owner == task_tgid(current)) {
1129 remove_notification(info);
1130 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1132 } else if (info->notify_owner != NULL) {
1135 switch (notification.sigev_notify) {
1137 info->notify.sigev_notify = SIGEV_NONE;
1140 info->notify_sock = sock;
1141 info->notify_cookie = nc;
1144 info->notify.sigev_notify = SIGEV_THREAD;
1147 info->notify.sigev_signo = notification.sigev_signo;
1148 info->notify.sigev_value = notification.sigev_value;
1149 info->notify.sigev_notify = SIGEV_SIGNAL;
1153 info->notify_owner = get_pid(task_tgid(current));
1154 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1156 spin_unlock(&info->lock);
1161 netlink_detachskb(sock, nc);
1168 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1169 const struct mq_attr __user *, u_mqstat,
1170 struct mq_attr __user *, u_omqstat)
1173 struct mq_attr mqstat, omqstat;
1175 struct inode *inode;
1176 struct mqueue_inode_info *info;
1178 if (u_mqstat != NULL) {
1179 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1181 if (mqstat.mq_flags & (~O_NONBLOCK))
1191 inode = filp->f_path.dentry->d_inode;
1192 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1196 info = MQUEUE_I(inode);
1198 spin_lock(&info->lock);
1200 omqstat = info->attr;
1201 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1203 audit_mq_getsetattr(mqdes, &mqstat);
1204 spin_lock(&filp->f_lock);
1205 if (mqstat.mq_flags & O_NONBLOCK)
1206 filp->f_flags |= O_NONBLOCK;
1208 filp->f_flags &= ~O_NONBLOCK;
1209 spin_unlock(&filp->f_lock);
1211 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1214 spin_unlock(&info->lock);
1217 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1218 sizeof(struct mq_attr)))
1227 static const struct inode_operations mqueue_dir_inode_operations = {
1228 .lookup = simple_lookup,
1229 .create = mqueue_create,
1230 .unlink = mqueue_unlink,
1233 static const struct file_operations mqueue_file_operations = {
1234 .flush = mqueue_flush_file,
1235 .poll = mqueue_poll_file,
1236 .read = mqueue_read_file,
1237 .llseek = default_llseek,
1240 static const struct super_operations mqueue_super_ops = {
1241 .alloc_inode = mqueue_alloc_inode,
1242 .destroy_inode = mqueue_destroy_inode,
1243 .evict_inode = mqueue_evict_inode,
1244 .statfs = simple_statfs,
1247 static struct file_system_type mqueue_fs_type = {
1249 .mount = mqueue_mount,
1250 .kill_sb = kill_litter_super,
1253 int mq_init_ns(struct ipc_namespace *ns)
1255 ns->mq_queues_count = 0;
1256 ns->mq_queues_max = DFLT_QUEUESMAX;
1257 ns->mq_msg_max = DFLT_MSGMAX;
1258 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1260 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1261 if (IS_ERR(ns->mq_mnt)) {
1262 int err = PTR_ERR(ns->mq_mnt);
1269 void mq_clear_sbinfo(struct ipc_namespace *ns)
1271 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1274 void mq_put_mnt(struct ipc_namespace *ns)
1276 kern_unmount(ns->mq_mnt);
1279 static int __init init_mqueue_fs(void)
1283 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1284 sizeof(struct mqueue_inode_info), 0,
1285 SLAB_HWCACHE_ALIGN, init_once);
1286 if (mqueue_inode_cachep == NULL)
1289 /* ignore failures - they are not fatal */
1290 mq_sysctl_table = mq_register_sysctl_table();
1292 error = register_filesystem(&mqueue_fs_type);
1296 spin_lock_init(&mq_lock);
1298 error = mq_init_ns(&init_ipc_ns);
1300 goto out_filesystem;
1305 unregister_filesystem(&mqueue_fs_type);
1307 if (mq_sysctl_table)
1308 unregister_sysctl_table(mq_sysctl_table);
1309 kmem_cache_destroy(mqueue_inode_cachep);
1313 __initcall(init_mqueue_fs);