netdev: restore MTU change operation
[linux/fpc-iii.git] / ipc / mqueue.c
blobe35ba2c3a8d770abd7fa97403616dbd8289d26e3
1 /*
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>
36 #include <net/sock.h>
37 #include "util.h"
39 #define MQUEUE_MAGIC 0x19800202
40 #define DIRENT_SIZE 20
41 #define FILENT_SIZE 80
43 #define SEND 0
44 #define RECV 1
46 #define STATE_NONE 0
47 #define STATE_PENDING 1
48 #define STATE_READY 2
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 {
58 spinlock_t lock;
59 struct inode vfs_inode;
60 wait_queue_head_t wait_q;
62 struct msg_msg **messages;
63 struct mq_attr attr;
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 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;
103 spin_lock(&mq_lock);
104 ns = __get_ns_from_inode(inode);
105 spin_unlock(&mq_lock);
106 return ns;
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();
114 struct inode *inode;
116 inode = new_inode(sb);
117 if (inode) {
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 =
122 CURRENT_TIME;
124 if (S_ISREG(mode)) {
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;
139 info->qsize = 0;
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;
144 if (attr) {
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));
152 spin_lock(&mq_lock);
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);
157 goto out_inode;
159 u->mq_bytes += mq_bytes;
160 spin_unlock(&mq_lock);
162 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
163 if (!info->messages) {
164 spin_lock(&mq_lock);
165 u->mq_bytes -= mq_bytes;
166 spin_unlock(&mq_lock);
167 goto out_inode;
169 /* all is ok */
170 info->user = get_uid(u);
171 } else if (S_ISDIR(mode)) {
172 inc_nlink(inode);
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;
179 return inode;
180 out_inode:
181 make_bad_inode(inode);
182 iput(inode);
183 return NULL;
186 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
188 struct inode *inode;
189 struct ipc_namespace *ns = data;
190 int error = 0;
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,
198 NULL);
199 if (!inode) {
200 error = -ENOMEM;
201 goto out;
204 sb->s_root = d_alloc_root(inode);
205 if (!sb->s_root) {
206 iput(inode);
207 error = -ENOMEM;
210 out:
211 return error;
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);
235 if (!ei)
236 return NULL;
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;
250 int i;
251 struct ipc_namespace *ipc_ns;
253 if (S_ISDIR(inode->i_mode)) {
254 clear_inode(inode);
255 return;
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);
265 clear_inode(inode);
267 mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
268 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
269 user = info->user;
270 if (user) {
271 spin_lock(&mq_lock);
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.
279 if (ipc_ns)
280 ipc_ns->mq_queues_count--;
281 spin_unlock(&mq_lock);
282 free_uid(user);
284 if (ipc_ns)
285 put_ipc_ns(ipc_ns);
288 static int mqueue_create(struct inode *dir, struct dentry *dentry,
289 int mode, struct nameidata *nd)
291 struct inode *inode;
292 struct mq_attr *attr = dentry->d_fsdata;
293 int error;
294 struct ipc_namespace *ipc_ns;
296 spin_lock(&mq_lock);
297 ipc_ns = __get_ns_from_inode(dir);
298 if (!ipc_ns) {
299 error = -EACCES;
300 goto out_unlock;
302 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
303 !capable(CAP_SYS_RESOURCE)) {
304 error = -ENOSPC;
305 goto out_unlock;
307 ipc_ns->mq_queues_count++;
308 spin_unlock(&mq_lock);
310 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
311 if (!inode) {
312 error = -ENOMEM;
313 spin_lock(&mq_lock);
314 ipc_ns->mq_queues_count--;
315 goto out_unlock;
318 put_ipc_ns(ipc_ns);
319 dir->i_size += DIRENT_SIZE;
320 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
322 d_instantiate(dentry, inode);
323 dget(dentry);
324 return 0;
325 out_unlock:
326 spin_unlock(&mq_lock);
327 if (ipc_ns)
328 put_ipc_ns(ipc_ns);
329 return error;
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;
338 drop_nlink(inode);
339 dput(dentry);
340 return 0;
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];
355 ssize_t ret;
357 spin_lock(&info->lock);
358 snprintf(buffer, sizeof(buffer),
359 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
360 info->qsize,
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,
370 strlen(buffer));
371 if (ret <= 0)
372 return ret;
374 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
375 return ret;
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);
387 return 0;
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);
393 int retval = 0;
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);
405 return retval;
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;
414 ewp->task = current;
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);
419 return;
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
427 * lock isn't held.
428 * sr: SEND or RECV
430 static int wq_sleep(struct mqueue_inode_info *info, int sr,
431 long timeout, struct ext_wait_queue *ewp)
433 int retval;
434 signed long time;
436 wq_add(info, sr, ewp);
438 for (;;) {
439 set_current_state(TASK_INTERRUPTIBLE);
441 spin_unlock(&info->lock);
442 time = schedule_timeout(timeout);
444 while (ewp->state == STATE_PENDING)
445 cpu_relax();
447 if (ewp->state == STATE_READY) {
448 retval = 0;
449 goto out;
451 spin_lock(&info->lock);
452 if (ewp->state == STATE_READY) {
453 retval = 0;
454 goto out_unlock;
456 if (signal_pending(current)) {
457 retval = -ERESTARTSYS;
458 break;
460 if (time == 0) {
461 retval = -ETIMEDOUT;
462 break;
465 list_del(&ewp->list);
466 out_unlock:
467 spin_unlock(&info->lock);
468 out:
469 return retval;
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)
482 return NULL;
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)
489 int k;
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];
494 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)
517 /* notification
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
521 * synchronously. */
522 if (info->notify_owner &&
523 info->attr.mq_curmsgs == 1) {
524 struct siginfo sig_i;
525 switch (info->notify.sigev_notify) {
526 case SIGEV_NONE:
527 break;
528 case SIGEV_SIGNAL:
529 /* sends signal */
531 sig_i.si_signo = info->notify.sigev_signo;
532 sig_i.si_errno = 0;
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);
541 break;
542 case SIGEV_THREAD:
543 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
544 netlink_sendskb(info->notify_sock, info->notify_cookie);
545 break;
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;
557 long timeout;
559 if (p) {
560 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
561 || p->tv_nsec >= NSEC_PER_SEC))
562 return -EINVAL;
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;
568 p->tv_sec--;
570 p->tv_nsec -= nowts.tv_nsec;
571 if (p->tv_sec < 0)
572 return 0;
574 timeout = timespec_to_jiffies(p) + 1;
575 } else
576 return MAX_SCHEDULE_TIMEOUT;
578 return 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)
595 return 0;
596 if (capable(CAP_SYS_RESOURCE)) {
597 if (attr->mq_maxmsg > HARD_MSGMAX)
598 return 0;
599 } else {
600 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
601 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
602 return 0;
604 /* check for overflow */
605 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
606 return 0;
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))
610 return 0;
611 return 1;
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();
622 struct file *result;
623 int ret;
625 if (attr) {
626 ret = -EINVAL;
627 if (!mq_attr_ok(ipc_ns, attr))
628 goto out;
629 /* store for use during create */
630 dentry->d_fsdata = attr;
633 mode &= ~current_umask();
634 ret = mnt_want_write(ipc_ns->mq_mnt);
635 if (ret)
636 goto out;
637 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
638 dentry->d_fsdata = NULL;
639 if (ret)
640 goto out_drop_write;
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);
648 return result;
650 out_drop_write:
651 mnt_drop_write(ipc_ns->mq_mnt);
652 out:
653 dput(dentry);
654 mntput(ipc_ns->mq_mnt);
655 return ERR_PTR(ret);
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)) {
668 dput(dentry);
669 mntput(ipc_ns->mq_mnt);
670 return ERR_PTR(-EINVAL);
673 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
674 dput(dentry);
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;
686 struct file *filp;
687 char *name;
688 struct mq_attr attr;
689 int fd, error;
690 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
692 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
693 return -EFAULT;
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);
701 if (fd < 0)
702 goto out_putname;
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);
708 goto out_err;
710 mntget(ipc_ns->mq_mnt);
712 if (oflag & O_CREAT) {
713 if (dentry->d_inode) { /* entry already exists */
714 audit_inode(name, dentry);
715 error = -EEXIST;
716 if (oflag & O_EXCL)
717 goto out;
718 filp = do_open(ipc_ns, dentry, oflag);
719 } else {
720 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
721 dentry, oflag, mode,
722 u_attr ? &attr : NULL);
724 } else {
725 error = -ENOENT;
726 if (!dentry->d_inode)
727 goto out;
728 audit_inode(name, dentry);
729 filp = do_open(ipc_ns, dentry, oflag);
732 if (IS_ERR(filp)) {
733 error = PTR_ERR(filp);
734 goto out_putfd;
737 fd_install(fd, filp);
738 goto out_upsem;
740 out:
741 dput(dentry);
742 mntput(ipc_ns->mq_mnt);
743 out_putfd:
744 put_unused_fd(fd);
745 out_err:
746 fd = error;
747 out_upsem:
748 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
749 out_putname:
750 putname(name);
751 return fd;
754 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
756 int err;
757 char *name;
758 struct dentry *dentry;
759 struct inode *inode = NULL;
760 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
762 name = getname(u_name);
763 if (IS_ERR(name))
764 return PTR_ERR(name);
766 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
767 I_MUTEX_PARENT);
768 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
769 if (IS_ERR(dentry)) {
770 err = PTR_ERR(dentry);
771 goto out_unlock;
774 if (!dentry->d_inode) {
775 err = -ENOENT;
776 goto out_err;
779 inode = dentry->d_inode;
780 if (inode)
781 atomic_inc(&inode->i_count);
782 err = mnt_want_write(ipc_ns->mq_mnt);
783 if (err)
784 goto out_err;
785 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
786 mnt_drop_write(ipc_ns->mq_mnt);
787 out_err:
788 dput(dentry);
790 out_unlock:
791 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
792 putname(name);
793 if (inode)
794 iput(inode);
796 return err;
799 /* Pipelined send and receive functions.
801 * If a receiver finds no waiting message, then it registers itself in the
802 * list of waiting receivers. A sender checks that list before adding the new
803 * message into the message array. If there is a waiting receiver, then it
804 * bypasses the message array and directly hands the message over to the
805 * receiver.
806 * The receiver accepts the message and returns without grabbing the queue
807 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
808 * are necessary. The same algorithm is used for sysv semaphores, see
809 * ipc/sem.c for more details.
811 * The same algorithm is used for senders.
814 /* pipelined_send() - send a message directly to the task waiting in
815 * sys_mq_timedreceive() (without inserting message into a queue).
817 static inline void pipelined_send(struct mqueue_inode_info *info,
818 struct msg_msg *message,
819 struct ext_wait_queue *receiver)
821 receiver->msg = message;
822 list_del(&receiver->list);
823 receiver->state = STATE_PENDING;
824 wake_up_process(receiver->task);
825 smp_wmb();
826 receiver->state = STATE_READY;
829 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
830 * gets its message and put to the queue (we have one free place for sure). */
831 static inline void pipelined_receive(struct mqueue_inode_info *info)
833 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
835 if (!sender) {
836 /* for poll */
837 wake_up_interruptible(&info->wait_q);
838 return;
840 msg_insert(sender->msg, info);
841 list_del(&sender->list);
842 sender->state = STATE_PENDING;
843 wake_up_process(sender->task);
844 smp_wmb();
845 sender->state = STATE_READY;
848 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
849 size_t, msg_len, unsigned int, msg_prio,
850 const struct timespec __user *, u_abs_timeout)
852 struct file *filp;
853 struct inode *inode;
854 struct ext_wait_queue wait;
855 struct ext_wait_queue *receiver;
856 struct msg_msg *msg_ptr;
857 struct mqueue_inode_info *info;
858 struct timespec ts, *p = NULL;
859 long timeout;
860 int ret;
862 if (u_abs_timeout) {
863 if (copy_from_user(&ts, u_abs_timeout,
864 sizeof(struct timespec)))
865 return -EFAULT;
866 p = &ts;
869 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
870 return -EINVAL;
872 audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
873 timeout = prepare_timeout(p);
875 ret = -EBADF;
876 filp = fget(mqdes);
877 if (unlikely(!filp))
878 goto out;
880 inode = filp->f_path.dentry->d_inode;
881 if (unlikely(filp->f_op != &mqueue_file_operations))
882 goto out_fput;
883 info = MQUEUE_I(inode);
884 audit_inode(NULL, filp->f_path.dentry);
886 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
887 goto out_fput;
889 if (unlikely(msg_len > info->attr.mq_msgsize)) {
890 ret = -EMSGSIZE;
891 goto out_fput;
894 /* First try to allocate memory, before doing anything with
895 * existing queues. */
896 msg_ptr = load_msg(u_msg_ptr, msg_len);
897 if (IS_ERR(msg_ptr)) {
898 ret = PTR_ERR(msg_ptr);
899 goto out_fput;
901 msg_ptr->m_ts = msg_len;
902 msg_ptr->m_type = msg_prio;
904 spin_lock(&info->lock);
906 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
907 if (filp->f_flags & O_NONBLOCK) {
908 spin_unlock(&info->lock);
909 ret = -EAGAIN;
910 } else if (unlikely(timeout < 0)) {
911 spin_unlock(&info->lock);
912 ret = timeout;
913 } else {
914 wait.task = current;
915 wait.msg = (void *) msg_ptr;
916 wait.state = STATE_NONE;
917 ret = wq_sleep(info, SEND, timeout, &wait);
919 if (ret < 0)
920 free_msg(msg_ptr);
921 } else {
922 receiver = wq_get_first_waiter(info, RECV);
923 if (receiver) {
924 pipelined_send(info, msg_ptr, receiver);
925 } else {
926 /* adds message to the queue */
927 msg_insert(msg_ptr, info);
928 __do_notify(info);
930 inode->i_atime = inode->i_mtime = inode->i_ctime =
931 CURRENT_TIME;
932 spin_unlock(&info->lock);
933 ret = 0;
935 out_fput:
936 fput(filp);
937 out:
938 return ret;
941 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
942 size_t, msg_len, unsigned int __user *, u_msg_prio,
943 const struct timespec __user *, u_abs_timeout)
945 long timeout;
946 ssize_t ret;
947 struct msg_msg *msg_ptr;
948 struct file *filp;
949 struct inode *inode;
950 struct mqueue_inode_info *info;
951 struct ext_wait_queue wait;
952 struct timespec ts, *p = NULL;
954 if (u_abs_timeout) {
955 if (copy_from_user(&ts, u_abs_timeout,
956 sizeof(struct timespec)))
957 return -EFAULT;
958 p = &ts;
961 audit_mq_sendrecv(mqdes, msg_len, 0, p);
962 timeout = prepare_timeout(p);
964 ret = -EBADF;
965 filp = fget(mqdes);
966 if (unlikely(!filp))
967 goto out;
969 inode = filp->f_path.dentry->d_inode;
970 if (unlikely(filp->f_op != &mqueue_file_operations))
971 goto out_fput;
972 info = MQUEUE_I(inode);
973 audit_inode(NULL, filp->f_path.dentry);
975 if (unlikely(!(filp->f_mode & FMODE_READ)))
976 goto out_fput;
978 /* checks if buffer is big enough */
979 if (unlikely(msg_len < info->attr.mq_msgsize)) {
980 ret = -EMSGSIZE;
981 goto out_fput;
984 spin_lock(&info->lock);
985 if (info->attr.mq_curmsgs == 0) {
986 if (filp->f_flags & O_NONBLOCK) {
987 spin_unlock(&info->lock);
988 ret = -EAGAIN;
989 msg_ptr = NULL;
990 } else if (unlikely(timeout < 0)) {
991 spin_unlock(&info->lock);
992 ret = timeout;
993 msg_ptr = NULL;
994 } else {
995 wait.task = current;
996 wait.state = STATE_NONE;
997 ret = wq_sleep(info, RECV, timeout, &wait);
998 msg_ptr = wait.msg;
1000 } else {
1001 msg_ptr = msg_get(info);
1003 inode->i_atime = inode->i_mtime = inode->i_ctime =
1004 CURRENT_TIME;
1006 /* There is now free space in queue. */
1007 pipelined_receive(info);
1008 spin_unlock(&info->lock);
1009 ret = 0;
1011 if (ret == 0) {
1012 ret = msg_ptr->m_ts;
1014 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1015 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1016 ret = -EFAULT;
1018 free_msg(msg_ptr);
1020 out_fput:
1021 fput(filp);
1022 out:
1023 return ret;
1027 * Notes: the case when user wants us to deregister (with NULL as pointer)
1028 * and he isn't currently owner of notification, will be silently discarded.
1029 * It isn't explicitly defined in the POSIX.
1031 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1032 const struct sigevent __user *, u_notification)
1034 int ret;
1035 struct file *filp;
1036 struct sock *sock;
1037 struct inode *inode;
1038 struct sigevent notification;
1039 struct mqueue_inode_info *info;
1040 struct sk_buff *nc;
1042 if (u_notification) {
1043 if (copy_from_user(&notification, u_notification,
1044 sizeof(struct sigevent)))
1045 return -EFAULT;
1048 audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1050 nc = NULL;
1051 sock = NULL;
1052 if (u_notification != NULL) {
1053 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1054 notification.sigev_notify != SIGEV_SIGNAL &&
1055 notification.sigev_notify != SIGEV_THREAD))
1056 return -EINVAL;
1057 if (notification.sigev_notify == SIGEV_SIGNAL &&
1058 !valid_signal(notification.sigev_signo)) {
1059 return -EINVAL;
1061 if (notification.sigev_notify == SIGEV_THREAD) {
1062 long timeo;
1064 /* create the notify skb */
1065 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1066 ret = -ENOMEM;
1067 if (!nc)
1068 goto out;
1069 ret = -EFAULT;
1070 if (copy_from_user(nc->data,
1071 notification.sigev_value.sival_ptr,
1072 NOTIFY_COOKIE_LEN)) {
1073 goto out;
1076 /* TODO: add a header? */
1077 skb_put(nc, NOTIFY_COOKIE_LEN);
1078 /* and attach it to the socket */
1079 retry:
1080 filp = fget(notification.sigev_signo);
1081 ret = -EBADF;
1082 if (!filp)
1083 goto out;
1084 sock = netlink_getsockbyfilp(filp);
1085 fput(filp);
1086 if (IS_ERR(sock)) {
1087 ret = PTR_ERR(sock);
1088 sock = NULL;
1089 goto out;
1092 timeo = MAX_SCHEDULE_TIMEOUT;
1093 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1094 if (ret == 1)
1095 goto retry;
1096 if (ret) {
1097 sock = NULL;
1098 nc = NULL;
1099 goto out;
1104 ret = -EBADF;
1105 filp = fget(mqdes);
1106 if (!filp)
1107 goto out;
1109 inode = filp->f_path.dentry->d_inode;
1110 if (unlikely(filp->f_op != &mqueue_file_operations))
1111 goto out_fput;
1112 info = MQUEUE_I(inode);
1114 ret = 0;
1115 spin_lock(&info->lock);
1116 if (u_notification == NULL) {
1117 if (info->notify_owner == task_tgid(current)) {
1118 remove_notification(info);
1119 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1121 } else if (info->notify_owner != NULL) {
1122 ret = -EBUSY;
1123 } else {
1124 switch (notification.sigev_notify) {
1125 case SIGEV_NONE:
1126 info->notify.sigev_notify = SIGEV_NONE;
1127 break;
1128 case SIGEV_THREAD:
1129 info->notify_sock = sock;
1130 info->notify_cookie = nc;
1131 sock = NULL;
1132 nc = NULL;
1133 info->notify.sigev_notify = SIGEV_THREAD;
1134 break;
1135 case SIGEV_SIGNAL:
1136 info->notify.sigev_signo = notification.sigev_signo;
1137 info->notify.sigev_value = notification.sigev_value;
1138 info->notify.sigev_notify = SIGEV_SIGNAL;
1139 break;
1142 info->notify_owner = get_pid(task_tgid(current));
1143 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1145 spin_unlock(&info->lock);
1146 out_fput:
1147 fput(filp);
1148 out:
1149 if (sock) {
1150 netlink_detachskb(sock, nc);
1151 } else if (nc) {
1152 dev_kfree_skb(nc);
1154 return ret;
1157 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1158 const struct mq_attr __user *, u_mqstat,
1159 struct mq_attr __user *, u_omqstat)
1161 int ret;
1162 struct mq_attr mqstat, omqstat;
1163 struct file *filp;
1164 struct inode *inode;
1165 struct mqueue_inode_info *info;
1167 if (u_mqstat != NULL) {
1168 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1169 return -EFAULT;
1170 if (mqstat.mq_flags & (~O_NONBLOCK))
1171 return -EINVAL;
1174 ret = -EBADF;
1175 filp = fget(mqdes);
1176 if (!filp)
1177 goto out;
1179 inode = filp->f_path.dentry->d_inode;
1180 if (unlikely(filp->f_op != &mqueue_file_operations))
1181 goto out_fput;
1182 info = MQUEUE_I(inode);
1184 spin_lock(&info->lock);
1186 omqstat = info->attr;
1187 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1188 if (u_mqstat) {
1189 audit_mq_getsetattr(mqdes, &mqstat);
1190 spin_lock(&filp->f_lock);
1191 if (mqstat.mq_flags & O_NONBLOCK)
1192 filp->f_flags |= O_NONBLOCK;
1193 else
1194 filp->f_flags &= ~O_NONBLOCK;
1195 spin_unlock(&filp->f_lock);
1197 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1200 spin_unlock(&info->lock);
1202 ret = 0;
1203 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1204 sizeof(struct mq_attr)))
1205 ret = -EFAULT;
1207 out_fput:
1208 fput(filp);
1209 out:
1210 return ret;
1213 static const struct inode_operations mqueue_dir_inode_operations = {
1214 .lookup = simple_lookup,
1215 .create = mqueue_create,
1216 .unlink = mqueue_unlink,
1219 static const struct file_operations mqueue_file_operations = {
1220 .flush = mqueue_flush_file,
1221 .poll = mqueue_poll_file,
1222 .read = mqueue_read_file,
1225 static struct super_operations mqueue_super_ops = {
1226 .alloc_inode = mqueue_alloc_inode,
1227 .destroy_inode = mqueue_destroy_inode,
1228 .statfs = simple_statfs,
1229 .delete_inode = mqueue_delete_inode,
1230 .drop_inode = generic_delete_inode,
1233 static struct file_system_type mqueue_fs_type = {
1234 .name = "mqueue",
1235 .get_sb = mqueue_get_sb,
1236 .kill_sb = kill_litter_super,
1239 int mq_init_ns(struct ipc_namespace *ns)
1241 ns->mq_queues_count = 0;
1242 ns->mq_queues_max = DFLT_QUEUESMAX;
1243 ns->mq_msg_max = DFLT_MSGMAX;
1244 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1246 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1247 if (IS_ERR(ns->mq_mnt)) {
1248 int err = PTR_ERR(ns->mq_mnt);
1249 ns->mq_mnt = NULL;
1250 return err;
1252 return 0;
1255 void mq_clear_sbinfo(struct ipc_namespace *ns)
1257 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1260 void mq_put_mnt(struct ipc_namespace *ns)
1262 mntput(ns->mq_mnt);
1265 static int __init init_mqueue_fs(void)
1267 int error;
1269 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1270 sizeof(struct mqueue_inode_info), 0,
1271 SLAB_HWCACHE_ALIGN, init_once);
1272 if (mqueue_inode_cachep == NULL)
1273 return -ENOMEM;
1275 /* ignore failues - they are not fatal */
1276 mq_sysctl_table = mq_register_sysctl_table();
1278 error = register_filesystem(&mqueue_fs_type);
1279 if (error)
1280 goto out_sysctl;
1282 spin_lock_init(&mq_lock);
1284 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1285 if (IS_ERR(init_ipc_ns.mq_mnt)) {
1286 error = PTR_ERR(init_ipc_ns.mq_mnt);
1287 goto out_filesystem;
1290 return 0;
1292 out_filesystem:
1293 unregister_filesystem(&mqueue_fs_type);
1294 out_sysctl:
1295 if (mq_sysctl_table)
1296 unregister_sysctl_table(mq_sysctl_table);
1297 kmem_cache_destroy(mqueue_inode_cachep);
1298 return error;
1301 __initcall(init_mqueue_fs);