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rapidio: apply RX/TX enable to active switch ports only
[deliverable/linux.git] / ipc / mqueue.c
1 /*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
6 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
13 * This file is released under the GPL.
14 */
15
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/vmalloc.h>
28 #include <linux/netlink.h>
29 #include <linux/syscalls.h>
30 #include <linux/audit.h>
31 #include <linux/signal.h>
32 #include <linux/mutex.h>
33 #include <linux/nsproxy.h>
34 #include <linux/pid.h>
35 #include <linux/ipc_namespace.h>
36 #include <linux/user_namespace.h>
37 #include <linux/slab.h>
38
39 #include <net/sock.h>
40 #include "util.h"
41
42 #define MQUEUE_MAGIC 0x19800202
43 #define DIRENT_SIZE 20
44 #define FILENT_SIZE 80
45
46 #define SEND 0
47 #define RECV 1
48
49 #define STATE_NONE 0
50 #define STATE_PENDING 1
51 #define STATE_READY 2
52
53 struct posix_msg_tree_node {
54 struct rb_node rb_node;
55 struct list_head msg_list;
56 int priority;
57 };
58
59 struct ext_wait_queue { /* queue of sleeping tasks */
60 struct task_struct *task;
61 struct list_head list;
62 struct msg_msg *msg; /* ptr of loaded message */
63 int state; /* one of STATE_* values */
64 };
65
66 struct mqueue_inode_info {
67 spinlock_t lock;
68 struct inode vfs_inode;
69 wait_queue_head_t wait_q;
70
71 struct rb_root msg_tree;
72 struct posix_msg_tree_node *node_cache;
73 struct mq_attr attr;
74
75 struct sigevent notify;
76 struct pid* notify_owner;
77 struct user_namespace *notify_user_ns;
78 struct user_struct *user; /* user who created, for accounting */
79 struct sock *notify_sock;
80 struct sk_buff *notify_cookie;
81
82 /* for tasks waiting for free space and messages, respectively */
83 struct ext_wait_queue e_wait_q[2];
84
85 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
86 };
87
88 static const struct inode_operations mqueue_dir_inode_operations;
89 static const struct file_operations mqueue_file_operations;
90 static const struct super_operations mqueue_super_ops;
91 static void remove_notification(struct mqueue_inode_info *info);
92
93 static struct kmem_cache *mqueue_inode_cachep;
94
95 static struct ctl_table_header * mq_sysctl_table;
96
97 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
98 {
99 return container_of(inode, struct mqueue_inode_info, vfs_inode);
100 }
101
102 /*
103 * This routine should be called with the mq_lock held.
104 */
105 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
106 {
107 return get_ipc_ns(inode->i_sb->s_fs_info);
108 }
109
110 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
111 {
112 struct ipc_namespace *ns;
113
114 spin_lock(&mq_lock);
115 ns = __get_ns_from_inode(inode);
116 spin_unlock(&mq_lock);
117 return ns;
118 }
119
120 /* Auxiliary functions to manipulate messages' list */
121 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
122 {
123 struct rb_node **p, *parent = NULL;
124 struct posix_msg_tree_node *leaf;
125
126 p = &info->msg_tree.rb_node;
127 while (*p) {
128 parent = *p;
129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
130
131 if (likely(leaf->priority == msg->m_type))
132 goto insert_msg;
133 else if (msg->m_type < leaf->priority)
134 p = &(*p)->rb_left;
135 else
136 p = &(*p)->rb_right;
137 }
138 if (info->node_cache) {
139 leaf = info->node_cache;
140 info->node_cache = NULL;
141 } else {
142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
143 if (!leaf)
144 return -ENOMEM;
145 rb_init_node(&leaf->rb_node);
146 INIT_LIST_HEAD(&leaf->msg_list);
147 info->qsize += sizeof(*leaf);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152 insert_msg:
153 info->attr.mq_curmsgs++;
154 info->qsize += msg->m_ts;
155 list_add_tail(&msg->m_list, &leaf->msg_list);
156 return 0;
157 }
158
159 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
160 {
161 struct rb_node **p, *parent = NULL;
162 struct posix_msg_tree_node *leaf;
163 struct msg_msg *msg;
164
165 try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 info->qsize -= sizeof(*leaf);
193 kfree(leaf);
194 } else {
195 info->node_cache = leaf;
196 }
197 goto try_again;
198 } else {
199 msg = list_first_entry(&leaf->msg_list,
200 struct msg_msg, m_list);
201 list_del(&msg->m_list);
202 if (list_empty(&leaf->msg_list)) {
203 rb_erase(&leaf->rb_node, &info->msg_tree);
204 if (info->node_cache) {
205 info->qsize -= sizeof(*leaf);
206 kfree(leaf);
207 } else {
208 info->node_cache = leaf;
209 }
210 }
211 }
212 info->attr.mq_curmsgs--;
213 info->qsize -= msg->m_ts;
214 return msg;
215 }
216
217 static struct inode *mqueue_get_inode(struct super_block *sb,
218 struct ipc_namespace *ipc_ns, umode_t mode,
219 struct mq_attr *attr)
220 {
221 struct user_struct *u = current_user();
222 struct inode *inode;
223 int ret = -ENOMEM;
224
225 inode = new_inode(sb);
226 if (!inode)
227 goto err;
228
229 inode->i_ino = get_next_ino();
230 inode->i_mode = mode;
231 inode->i_uid = current_fsuid();
232 inode->i_gid = current_fsgid();
233 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
234
235 if (S_ISREG(mode)) {
236 struct mqueue_inode_info *info;
237 unsigned long mq_bytes, mq_treesize;
238
239 inode->i_fop = &mqueue_file_operations;
240 inode->i_size = FILENT_SIZE;
241 /* mqueue specific info */
242 info = MQUEUE_I(inode);
243 spin_lock_init(&info->lock);
244 init_waitqueue_head(&info->wait_q);
245 INIT_LIST_HEAD(&info->e_wait_q[0].list);
246 INIT_LIST_HEAD(&info->e_wait_q[1].list);
247 info->notify_owner = NULL;
248 info->notify_user_ns = NULL;
249 info->qsize = 0;
250 info->user = NULL; /* set when all is ok */
251 info->msg_tree = RB_ROOT;
252 info->node_cache = NULL;
253 memset(&info->attr, 0, sizeof(info->attr));
254 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
255 ipc_ns->mq_msg_default);
256 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
257 ipc_ns->mq_msgsize_default);
258 if (attr) {
259 info->attr.mq_maxmsg = attr->mq_maxmsg;
260 info->attr.mq_msgsize = attr->mq_msgsize;
261 }
262 /*
263 * We used to allocate a static array of pointers and account
264 * the size of that array as well as one msg_msg struct per
265 * possible message into the queue size. That's no longer
266 * accurate as the queue is now an rbtree and will grow and
267 * shrink depending on usage patterns. We can, however, still
268 * account one msg_msg struct per message, but the nodes are
269 * allocated depending on priority usage, and most programs
270 * only use one, or a handful, of priorities. However, since
271 * this is pinned memory, we need to assume worst case, so
272 * that means the min(mq_maxmsg, max_priorities) * struct
273 * posix_msg_tree_node.
274 */
275 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
276 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
277 sizeof(struct posix_msg_tree_node);
278
279 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
280 info->attr.mq_msgsize);
281
282 spin_lock(&mq_lock);
283 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
284 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
285 spin_unlock(&mq_lock);
286 /* mqueue_evict_inode() releases info->messages */
287 ret = -EMFILE;
288 goto out_inode;
289 }
290 u->mq_bytes += mq_bytes;
291 spin_unlock(&mq_lock);
292
293 /* all is ok */
294 info->user = get_uid(u);
295 } else if (S_ISDIR(mode)) {
296 inc_nlink(inode);
297 /* Some things misbehave if size == 0 on a directory */
298 inode->i_size = 2 * DIRENT_SIZE;
299 inode->i_op = &mqueue_dir_inode_operations;
300 inode->i_fop = &simple_dir_operations;
301 }
302
303 return inode;
304 out_inode:
305 iput(inode);
306 err:
307 return ERR_PTR(ret);
308 }
309
310 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
311 {
312 struct inode *inode;
313 struct ipc_namespace *ns = data;
314
315 sb->s_blocksize = PAGE_CACHE_SIZE;
316 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
317 sb->s_magic = MQUEUE_MAGIC;
318 sb->s_op = &mqueue_super_ops;
319
320 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
321 if (IS_ERR(inode))
322 return PTR_ERR(inode);
323
324 sb->s_root = d_make_root(inode);
325 if (!sb->s_root)
326 return -ENOMEM;
327 return 0;
328 }
329
330 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
331 int flags, const char *dev_name,
332 void *data)
333 {
334 if (!(flags & MS_KERNMOUNT))
335 data = current->nsproxy->ipc_ns;
336 return mount_ns(fs_type, flags, data, mqueue_fill_super);
337 }
338
339 static void init_once(void *foo)
340 {
341 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
342
343 inode_init_once(&p->vfs_inode);
344 }
345
346 static struct inode *mqueue_alloc_inode(struct super_block *sb)
347 {
348 struct mqueue_inode_info *ei;
349
350 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
351 if (!ei)
352 return NULL;
353 return &ei->vfs_inode;
354 }
355
356 static void mqueue_i_callback(struct rcu_head *head)
357 {
358 struct inode *inode = container_of(head, struct inode, i_rcu);
359 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
360 }
361
362 static void mqueue_destroy_inode(struct inode *inode)
363 {
364 call_rcu(&inode->i_rcu, mqueue_i_callback);
365 }
366
367 static void mqueue_evict_inode(struct inode *inode)
368 {
369 struct mqueue_inode_info *info;
370 struct user_struct *user;
371 unsigned long mq_bytes, mq_treesize;
372 struct ipc_namespace *ipc_ns;
373 struct msg_msg *msg;
374
375 clear_inode(inode);
376
377 if (S_ISDIR(inode->i_mode))
378 return;
379
380 ipc_ns = get_ns_from_inode(inode);
381 info = MQUEUE_I(inode);
382 spin_lock(&info->lock);
383 while ((msg = msg_get(info)) != NULL)
384 free_msg(msg);
385 kfree(info->node_cache);
386 spin_unlock(&info->lock);
387
388 /* Total amount of bytes accounted for the mqueue */
389 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
390 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
391 sizeof(struct posix_msg_tree_node);
392
393 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
394 info->attr.mq_msgsize);
395
396 user = info->user;
397 if (user) {
398 spin_lock(&mq_lock);
399 user->mq_bytes -= mq_bytes;
400 /*
401 * get_ns_from_inode() ensures that the
402 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
403 * to which we now hold a reference, or it is NULL.
404 * We can't put it here under mq_lock, though.
405 */
406 if (ipc_ns)
407 ipc_ns->mq_queues_count--;
408 spin_unlock(&mq_lock);
409 free_uid(user);
410 }
411 if (ipc_ns)
412 put_ipc_ns(ipc_ns);
413 }
414
415 static int mqueue_create(struct inode *dir, struct dentry *dentry,
416 umode_t mode, bool excl)
417 {
418 struct inode *inode;
419 struct mq_attr *attr = dentry->d_fsdata;
420 int error;
421 struct ipc_namespace *ipc_ns;
422
423 spin_lock(&mq_lock);
424 ipc_ns = __get_ns_from_inode(dir);
425 if (!ipc_ns) {
426 error = -EACCES;
427 goto out_unlock;
428 }
429 if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
430 (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
431 !capable(CAP_SYS_RESOURCE))) {
432 error = -ENOSPC;
433 goto out_unlock;
434 }
435 ipc_ns->mq_queues_count++;
436 spin_unlock(&mq_lock);
437
438 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
439 if (IS_ERR(inode)) {
440 error = PTR_ERR(inode);
441 spin_lock(&mq_lock);
442 ipc_ns->mq_queues_count--;
443 goto out_unlock;
444 }
445
446 put_ipc_ns(ipc_ns);
447 dir->i_size += DIRENT_SIZE;
448 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
449
450 d_instantiate(dentry, inode);
451 dget(dentry);
452 return 0;
453 out_unlock:
454 spin_unlock(&mq_lock);
455 if (ipc_ns)
456 put_ipc_ns(ipc_ns);
457 return error;
458 }
459
460 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
461 {
462 struct inode *inode = dentry->d_inode;
463
464 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
465 dir->i_size -= DIRENT_SIZE;
466 drop_nlink(inode);
467 dput(dentry);
468 return 0;
469 }
470
471 /*
472 * This is routine for system read from queue file.
473 * To avoid mess with doing here some sort of mq_receive we allow
474 * to read only queue size & notification info (the only values
475 * that are interesting from user point of view and aren't accessible
476 * through std routines)
477 */
478 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
479 size_t count, loff_t *off)
480 {
481 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
482 char buffer[FILENT_SIZE];
483 ssize_t ret;
484
485 spin_lock(&info->lock);
486 snprintf(buffer, sizeof(buffer),
487 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
488 info->qsize,
489 info->notify_owner ? info->notify.sigev_notify : 0,
490 (info->notify_owner &&
491 info->notify.sigev_notify == SIGEV_SIGNAL) ?
492 info->notify.sigev_signo : 0,
493 pid_vnr(info->notify_owner));
494 spin_unlock(&info->lock);
495 buffer[sizeof(buffer)-1] = '\0';
496
497 ret = simple_read_from_buffer(u_data, count, off, buffer,
498 strlen(buffer));
499 if (ret <= 0)
500 return ret;
501
502 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
503 return ret;
504 }
505
506 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
507 {
508 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
509
510 spin_lock(&info->lock);
511 if (task_tgid(current) == info->notify_owner)
512 remove_notification(info);
513
514 spin_unlock(&info->lock);
515 return 0;
516 }
517
518 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
519 {
520 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
521 int retval = 0;
522
523 poll_wait(filp, &info->wait_q, poll_tab);
524
525 spin_lock(&info->lock);
526 if (info->attr.mq_curmsgs)
527 retval = POLLIN | POLLRDNORM;
528
529 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
530 retval |= POLLOUT | POLLWRNORM;
531 spin_unlock(&info->lock);
532
533 return retval;
534 }
535
536 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
537 static void wq_add(struct mqueue_inode_info *info, int sr,
538 struct ext_wait_queue *ewp)
539 {
540 struct ext_wait_queue *walk;
541
542 ewp->task = current;
543
544 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
545 if (walk->task->static_prio <= current->static_prio) {
546 list_add_tail(&ewp->list, &walk->list);
547 return;
548 }
549 }
550 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
551 }
552
553 /*
554 * Puts current task to sleep. Caller must hold queue lock. After return
555 * lock isn't held.
556 * sr: SEND or RECV
557 */
558 static int wq_sleep(struct mqueue_inode_info *info, int sr,
559 ktime_t *timeout, struct ext_wait_queue *ewp)
560 {
561 int retval;
562 signed long time;
563
564 wq_add(info, sr, ewp);
565
566 for (;;) {
567 set_current_state(TASK_INTERRUPTIBLE);
568
569 spin_unlock(&info->lock);
570 time = schedule_hrtimeout_range_clock(timeout, 0,
571 HRTIMER_MODE_ABS, CLOCK_REALTIME);
572
573 while (ewp->state == STATE_PENDING)
574 cpu_relax();
575
576 if (ewp->state == STATE_READY) {
577 retval = 0;
578 goto out;
579 }
580 spin_lock(&info->lock);
581 if (ewp->state == STATE_READY) {
582 retval = 0;
583 goto out_unlock;
584 }
585 if (signal_pending(current)) {
586 retval = -ERESTARTSYS;
587 break;
588 }
589 if (time == 0) {
590 retval = -ETIMEDOUT;
591 break;
592 }
593 }
594 list_del(&ewp->list);
595 out_unlock:
596 spin_unlock(&info->lock);
597 out:
598 return retval;
599 }
600
601 /*
602 * Returns waiting task that should be serviced first or NULL if none exists
603 */
604 static struct ext_wait_queue *wq_get_first_waiter(
605 struct mqueue_inode_info *info, int sr)
606 {
607 struct list_head *ptr;
608
609 ptr = info->e_wait_q[sr].list.prev;
610 if (ptr == &info->e_wait_q[sr].list)
611 return NULL;
612 return list_entry(ptr, struct ext_wait_queue, list);
613 }
614
615
616 static inline void set_cookie(struct sk_buff *skb, char code)
617 {
618 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
619 }
620
621 /*
622 * The next function is only to split too long sys_mq_timedsend
623 */
624 static void __do_notify(struct mqueue_inode_info *info)
625 {
626 /* notification
627 * invoked when there is registered process and there isn't process
628 * waiting synchronously for message AND state of queue changed from
629 * empty to not empty. Here we are sure that no one is waiting
630 * synchronously. */
631 if (info->notify_owner &&
632 info->attr.mq_curmsgs == 1) {
633 struct siginfo sig_i;
634 switch (info->notify.sigev_notify) {
635 case SIGEV_NONE:
636 break;
637 case SIGEV_SIGNAL:
638 /* sends signal */
639
640 sig_i.si_signo = info->notify.sigev_signo;
641 sig_i.si_errno = 0;
642 sig_i.si_code = SI_MESGQ;
643 sig_i.si_value = info->notify.sigev_value;
644 /* map current pid/uid into info->owner's namespaces */
645 rcu_read_lock();
646 sig_i.si_pid = task_tgid_nr_ns(current,
647 ns_of_pid(info->notify_owner));
648 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
649 rcu_read_unlock();
650
651 kill_pid_info(info->notify.sigev_signo,
652 &sig_i, info->notify_owner);
653 break;
654 case SIGEV_THREAD:
655 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
656 netlink_sendskb(info->notify_sock, info->notify_cookie);
657 break;
658 }
659 /* after notification unregisters process */
660 put_pid(info->notify_owner);
661 put_user_ns(info->notify_user_ns);
662 info->notify_owner = NULL;
663 info->notify_user_ns = NULL;
664 }
665 wake_up(&info->wait_q);
666 }
667
668 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
669 ktime_t *expires, struct timespec *ts)
670 {
671 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
672 return -EFAULT;
673 if (!timespec_valid(ts))
674 return -EINVAL;
675
676 *expires = timespec_to_ktime(*ts);
677 return 0;
678 }
679
680 static void remove_notification(struct mqueue_inode_info *info)
681 {
682 if (info->notify_owner != NULL &&
683 info->notify.sigev_notify == SIGEV_THREAD) {
684 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
685 netlink_sendskb(info->notify_sock, info->notify_cookie);
686 }
687 put_pid(info->notify_owner);
688 put_user_ns(info->notify_user_ns);
689 info->notify_owner = NULL;
690 info->notify_user_ns = NULL;
691 }
692
693 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
694 {
695 int mq_treesize;
696 unsigned long total_size;
697
698 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
699 return -EINVAL;
700 if (capable(CAP_SYS_RESOURCE)) {
701 if (attr->mq_maxmsg > HARD_MSGMAX ||
702 attr->mq_msgsize > HARD_MSGSIZEMAX)
703 return -EINVAL;
704 } else {
705 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
706 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
707 return -EINVAL;
708 }
709 /* check for overflow */
710 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
711 return -EOVERFLOW;
712 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
713 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
714 sizeof(struct posix_msg_tree_node);
715 total_size = attr->mq_maxmsg * attr->mq_msgsize;
716 if (total_size + mq_treesize < total_size)
717 return -EOVERFLOW;
718 return 0;
719 }
720
721 /*
722 * Invoked when creating a new queue via sys_mq_open
723 */
724 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
725 struct path *path, int oflag, umode_t mode,
726 struct mq_attr *attr)
727 {
728 const struct cred *cred = current_cred();
729 int ret;
730
731 if (attr) {
732 ret = mq_attr_ok(ipc_ns, attr);
733 if (ret)
734 return ERR_PTR(ret);
735 /* store for use during create */
736 path->dentry->d_fsdata = attr;
737 } else {
738 struct mq_attr def_attr;
739
740 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
741 ipc_ns->mq_msg_default);
742 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
743 ipc_ns->mq_msgsize_default);
744 ret = mq_attr_ok(ipc_ns, &def_attr);
745 if (ret)
746 return ERR_PTR(ret);
747 }
748
749 mode &= ~current_umask();
750 ret = vfs_create(dir, path->dentry, mode, true);
751 path->dentry->d_fsdata = NULL;
752 if (ret)
753 return ERR_PTR(ret);
754 return dentry_open(path, oflag, cred);
755 }
756
757 /* Opens existing queue */
758 static struct file *do_open(struct path *path, int oflag)
759 {
760 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
761 MAY_READ | MAY_WRITE };
762 int acc;
763 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
764 return ERR_PTR(-EINVAL);
765 acc = oflag2acc[oflag & O_ACCMODE];
766 if (inode_permission(path->dentry->d_inode, acc))
767 return ERR_PTR(-EACCES);
768 return dentry_open(path, oflag, current_cred());
769 }
770
771 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
772 struct mq_attr __user *, u_attr)
773 {
774 struct path path;
775 struct file *filp;
776 char *name;
777 struct mq_attr attr;
778 int fd, error;
779 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
780 struct vfsmount *mnt = ipc_ns->mq_mnt;
781 struct dentry *root = mnt->mnt_root;
782 int ro;
783
784 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
785 return -EFAULT;
786
787 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
788
789 if (IS_ERR(name = getname(u_name)))
790 return PTR_ERR(name);
791
792 fd = get_unused_fd_flags(O_CLOEXEC);
793 if (fd < 0)
794 goto out_putname;
795
796 ro = mnt_want_write(mnt); /* we'll drop it in any case */
797 error = 0;
798 mutex_lock(&root->d_inode->i_mutex);
799 path.dentry = lookup_one_len(name, root, strlen(name));
800 if (IS_ERR(path.dentry)) {
801 error = PTR_ERR(path.dentry);
802 goto out_putfd;
803 }
804 path.mnt = mntget(mnt);
805
806 if (oflag & O_CREAT) {
807 if (path.dentry->d_inode) { /* entry already exists */
808 audit_inode(name, path.dentry);
809 if (oflag & O_EXCL) {
810 error = -EEXIST;
811 goto out;
812 }
813 filp = do_open(&path, oflag);
814 } else {
815 if (ro) {
816 error = ro;
817 goto out;
818 }
819 filp = do_create(ipc_ns, root->d_inode,
820 &path, oflag, mode,
821 u_attr ? &attr : NULL);
822 }
823 } else {
824 if (!path.dentry->d_inode) {
825 error = -ENOENT;
826 goto out;
827 }
828 audit_inode(name, path.dentry);
829 filp = do_open(&path, oflag);
830 }
831
832 if (!IS_ERR(filp))
833 fd_install(fd, filp);
834 else
835 error = PTR_ERR(filp);
836 out:
837 path_put(&path);
838 out_putfd:
839 if (error) {
840 put_unused_fd(fd);
841 fd = error;
842 }
843 mutex_unlock(&root->d_inode->i_mutex);
844 mnt_drop_write(mnt);
845 out_putname:
846 putname(name);
847 return fd;
848 }
849
850 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
851 {
852 int err;
853 char *name;
854 struct dentry *dentry;
855 struct inode *inode = NULL;
856 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
857 struct vfsmount *mnt = ipc_ns->mq_mnt;
858
859 name = getname(u_name);
860 if (IS_ERR(name))
861 return PTR_ERR(name);
862
863 err = mnt_want_write(mnt);
864 if (err)
865 goto out_name;
866 mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT);
867 dentry = lookup_one_len(name, mnt->mnt_root, strlen(name));
868 if (IS_ERR(dentry)) {
869 err = PTR_ERR(dentry);
870 goto out_unlock;
871 }
872
873 inode = dentry->d_inode;
874 if (!inode) {
875 err = -ENOENT;
876 } else {
877 ihold(inode);
878 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
879 }
880 dput(dentry);
881
882 out_unlock:
883 mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
884 if (inode)
885 iput(inode);
886 mnt_drop_write(mnt);
887 out_name:
888 putname(name);
889
890 return err;
891 }
892
893 /* Pipelined send and receive functions.
894 *
895 * If a receiver finds no waiting message, then it registers itself in the
896 * list of waiting receivers. A sender checks that list before adding the new
897 * message into the message array. If there is a waiting receiver, then it
898 * bypasses the message array and directly hands the message over to the
899 * receiver.
900 * The receiver accepts the message and returns without grabbing the queue
901 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
902 * are necessary. The same algorithm is used for sysv semaphores, see
903 * ipc/sem.c for more details.
904 *
905 * The same algorithm is used for senders.
906 */
907
908 /* pipelined_send() - send a message directly to the task waiting in
909 * sys_mq_timedreceive() (without inserting message into a queue).
910 */
911 static inline void pipelined_send(struct mqueue_inode_info *info,
912 struct msg_msg *message,
913 struct ext_wait_queue *receiver)
914 {
915 receiver->msg = message;
916 list_del(&receiver->list);
917 receiver->state = STATE_PENDING;
918 wake_up_process(receiver->task);
919 smp_wmb();
920 receiver->state = STATE_READY;
921 }
922
923 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
924 * gets its message and put to the queue (we have one free place for sure). */
925 static inline void pipelined_receive(struct mqueue_inode_info *info)
926 {
927 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
928
929 if (!sender) {
930 /* for poll */
931 wake_up_interruptible(&info->wait_q);
932 return;
933 }
934 if (msg_insert(sender->msg, info))
935 return;
936 list_del(&sender->list);
937 sender->state = STATE_PENDING;
938 wake_up_process(sender->task);
939 smp_wmb();
940 sender->state = STATE_READY;
941 }
942
943 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
944 size_t, msg_len, unsigned int, msg_prio,
945 const struct timespec __user *, u_abs_timeout)
946 {
947 struct fd f;
948 struct inode *inode;
949 struct ext_wait_queue wait;
950 struct ext_wait_queue *receiver;
951 struct msg_msg *msg_ptr;
952 struct mqueue_inode_info *info;
953 ktime_t expires, *timeout = NULL;
954 struct timespec ts;
955 struct posix_msg_tree_node *new_leaf = NULL;
956 int ret = 0;
957
958 if (u_abs_timeout) {
959 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
960 if (res)
961 return res;
962 timeout = &expires;
963 }
964
965 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
966 return -EINVAL;
967
968 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
969
970 f = fdget(mqdes);
971 if (unlikely(!f.file)) {
972 ret = -EBADF;
973 goto out;
974 }
975
976 inode = f.file->f_path.dentry->d_inode;
977 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
978 ret = -EBADF;
979 goto out_fput;
980 }
981 info = MQUEUE_I(inode);
982 audit_inode(NULL, f.file->f_path.dentry);
983
984 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
985 ret = -EBADF;
986 goto out_fput;
987 }
988
989 if (unlikely(msg_len > info->attr.mq_msgsize)) {
990 ret = -EMSGSIZE;
991 goto out_fput;
992 }
993
994 /* First try to allocate memory, before doing anything with
995 * existing queues. */
996 msg_ptr = load_msg(u_msg_ptr, msg_len);
997 if (IS_ERR(msg_ptr)) {
998 ret = PTR_ERR(msg_ptr);
999 goto out_fput;
1000 }
1001 msg_ptr->m_ts = msg_len;
1002 msg_ptr->m_type = msg_prio;
1003
1004 /*
1005 * msg_insert really wants us to have a valid, spare node struct so
1006 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1007 * fall back to that if necessary.
1008 */
1009 if (!info->node_cache)
1010 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1011
1012 spin_lock(&info->lock);
1013
1014 if (!info->node_cache && new_leaf) {
1015 /* Save our speculative allocation into the cache */
1016 rb_init_node(&new_leaf->rb_node);
1017 INIT_LIST_HEAD(&new_leaf->msg_list);
1018 info->node_cache = new_leaf;
1019 info->qsize += sizeof(*new_leaf);
1020 new_leaf = NULL;
1021 } else {
1022 kfree(new_leaf);
1023 }
1024
1025 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1026 if (f.file->f_flags & O_NONBLOCK) {
1027 ret = -EAGAIN;
1028 } else {
1029 wait.task = current;
1030 wait.msg = (void *) msg_ptr;
1031 wait.state = STATE_NONE;
1032 ret = wq_sleep(info, SEND, timeout, &wait);
1033 /*
1034 * wq_sleep must be called with info->lock held, and
1035 * returns with the lock released
1036 */
1037 goto out_free;
1038 }
1039 } else {
1040 receiver = wq_get_first_waiter(info, RECV);
1041 if (receiver) {
1042 pipelined_send(info, msg_ptr, receiver);
1043 } else {
1044 /* adds message to the queue */
1045 ret = msg_insert(msg_ptr, info);
1046 if (ret)
1047 goto out_unlock;
1048 __do_notify(info);
1049 }
1050 inode->i_atime = inode->i_mtime = inode->i_ctime =
1051 CURRENT_TIME;
1052 }
1053 out_unlock:
1054 spin_unlock(&info->lock);
1055 out_free:
1056 if (ret)
1057 free_msg(msg_ptr);
1058 out_fput:
1059 fdput(f);
1060 out:
1061 return ret;
1062 }
1063
1064 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1065 size_t, msg_len, unsigned int __user *, u_msg_prio,
1066 const struct timespec __user *, u_abs_timeout)
1067 {
1068 ssize_t ret;
1069 struct msg_msg *msg_ptr;
1070 struct fd f;
1071 struct inode *inode;
1072 struct mqueue_inode_info *info;
1073 struct ext_wait_queue wait;
1074 ktime_t expires, *timeout = NULL;
1075 struct timespec ts;
1076 struct posix_msg_tree_node *new_leaf = NULL;
1077
1078 if (u_abs_timeout) {
1079 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1080 if (res)
1081 return res;
1082 timeout = &expires;
1083 }
1084
1085 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1086
1087 f = fdget(mqdes);
1088 if (unlikely(!f.file)) {
1089 ret = -EBADF;
1090 goto out;
1091 }
1092
1093 inode = f.file->f_path.dentry->d_inode;
1094 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1095 ret = -EBADF;
1096 goto out_fput;
1097 }
1098 info = MQUEUE_I(inode);
1099 audit_inode(NULL, f.file->f_path.dentry);
1100
1101 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1102 ret = -EBADF;
1103 goto out_fput;
1104 }
1105
1106 /* checks if buffer is big enough */
1107 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1108 ret = -EMSGSIZE;
1109 goto out_fput;
1110 }
1111
1112 /*
1113 * msg_insert really wants us to have a valid, spare node struct so
1114 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1115 * fall back to that if necessary.
1116 */
1117 if (!info->node_cache)
1118 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1119
1120 spin_lock(&info->lock);
1121
1122 if (!info->node_cache && new_leaf) {
1123 /* Save our speculative allocation into the cache */
1124 rb_init_node(&new_leaf->rb_node);
1125 INIT_LIST_HEAD(&new_leaf->msg_list);
1126 info->node_cache = new_leaf;
1127 info->qsize += sizeof(*new_leaf);
1128 } else {
1129 kfree(new_leaf);
1130 }
1131
1132 if (info->attr.mq_curmsgs == 0) {
1133 if (f.file->f_flags & O_NONBLOCK) {
1134 spin_unlock(&info->lock);
1135 ret = -EAGAIN;
1136 } else {
1137 wait.task = current;
1138 wait.state = STATE_NONE;
1139 ret = wq_sleep(info, RECV, timeout, &wait);
1140 msg_ptr = wait.msg;
1141 }
1142 } else {
1143 msg_ptr = msg_get(info);
1144
1145 inode->i_atime = inode->i_mtime = inode->i_ctime =
1146 CURRENT_TIME;
1147
1148 /* There is now free space in queue. */
1149 pipelined_receive(info);
1150 spin_unlock(&info->lock);
1151 ret = 0;
1152 }
1153 if (ret == 0) {
1154 ret = msg_ptr->m_ts;
1155
1156 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1157 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1158 ret = -EFAULT;
1159 }
1160 free_msg(msg_ptr);
1161 }
1162 out_fput:
1163 fdput(f);
1164 out:
1165 return ret;
1166 }
1167
1168 /*
1169 * Notes: the case when user wants us to deregister (with NULL as pointer)
1170 * and he isn't currently owner of notification, will be silently discarded.
1171 * It isn't explicitly defined in the POSIX.
1172 */
1173 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1174 const struct sigevent __user *, u_notification)
1175 {
1176 int ret;
1177 struct fd f;
1178 struct sock *sock;
1179 struct inode *inode;
1180 struct sigevent notification;
1181 struct mqueue_inode_info *info;
1182 struct sk_buff *nc;
1183
1184 if (u_notification) {
1185 if (copy_from_user(&notification, u_notification,
1186 sizeof(struct sigevent)))
1187 return -EFAULT;
1188 }
1189
1190 audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1191
1192 nc = NULL;
1193 sock = NULL;
1194 if (u_notification != NULL) {
1195 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1196 notification.sigev_notify != SIGEV_SIGNAL &&
1197 notification.sigev_notify != SIGEV_THREAD))
1198 return -EINVAL;
1199 if (notification.sigev_notify == SIGEV_SIGNAL &&
1200 !valid_signal(notification.sigev_signo)) {
1201 return -EINVAL;
1202 }
1203 if (notification.sigev_notify == SIGEV_THREAD) {
1204 long timeo;
1205
1206 /* create the notify skb */
1207 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1208 if (!nc) {
1209 ret = -ENOMEM;
1210 goto out;
1211 }
1212 if (copy_from_user(nc->data,
1213 notification.sigev_value.sival_ptr,
1214 NOTIFY_COOKIE_LEN)) {
1215 ret = -EFAULT;
1216 goto out;
1217 }
1218
1219 /* TODO: add a header? */
1220 skb_put(nc, NOTIFY_COOKIE_LEN);
1221 /* and attach it to the socket */
1222 retry:
1223 f = fdget(notification.sigev_signo);
1224 if (!f.file) {
1225 ret = -EBADF;
1226 goto out;
1227 }
1228 sock = netlink_getsockbyfilp(f.file);
1229 fdput(f);
1230 if (IS_ERR(sock)) {
1231 ret = PTR_ERR(sock);
1232 sock = NULL;
1233 goto out;
1234 }
1235
1236 timeo = MAX_SCHEDULE_TIMEOUT;
1237 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1238 if (ret == 1)
1239 goto retry;
1240 if (ret) {
1241 sock = NULL;
1242 nc = NULL;
1243 goto out;
1244 }
1245 }
1246 }
1247
1248 f = fdget(mqdes);
1249 if (!f.file) {
1250 ret = -EBADF;
1251 goto out;
1252 }
1253
1254 inode = f.file->f_path.dentry->d_inode;
1255 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1256 ret = -EBADF;
1257 goto out_fput;
1258 }
1259 info = MQUEUE_I(inode);
1260
1261 ret = 0;
1262 spin_lock(&info->lock);
1263 if (u_notification == NULL) {
1264 if (info->notify_owner == task_tgid(current)) {
1265 remove_notification(info);
1266 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1267 }
1268 } else if (info->notify_owner != NULL) {
1269 ret = -EBUSY;
1270 } else {
1271 switch (notification.sigev_notify) {
1272 case SIGEV_NONE:
1273 info->notify.sigev_notify = SIGEV_NONE;
1274 break;
1275 case SIGEV_THREAD:
1276 info->notify_sock = sock;
1277 info->notify_cookie = nc;
1278 sock = NULL;
1279 nc = NULL;
1280 info->notify.sigev_notify = SIGEV_THREAD;
1281 break;
1282 case SIGEV_SIGNAL:
1283 info->notify.sigev_signo = notification.sigev_signo;
1284 info->notify.sigev_value = notification.sigev_value;
1285 info->notify.sigev_notify = SIGEV_SIGNAL;
1286 break;
1287 }
1288
1289 info->notify_owner = get_pid(task_tgid(current));
1290 info->notify_user_ns = get_user_ns(current_user_ns());
1291 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1292 }
1293 spin_unlock(&info->lock);
1294 out_fput:
1295 fdput(f);
1296 out:
1297 if (sock) {
1298 netlink_detachskb(sock, nc);
1299 } else if (nc) {
1300 dev_kfree_skb(nc);
1301 }
1302 return ret;
1303 }
1304
1305 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1306 const struct mq_attr __user *, u_mqstat,
1307 struct mq_attr __user *, u_omqstat)
1308 {
1309 int ret;
1310 struct mq_attr mqstat, omqstat;
1311 struct fd f;
1312 struct inode *inode;
1313 struct mqueue_inode_info *info;
1314
1315 if (u_mqstat != NULL) {
1316 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1317 return -EFAULT;
1318 if (mqstat.mq_flags & (~O_NONBLOCK))
1319 return -EINVAL;
1320 }
1321
1322 f = fdget(mqdes);
1323 if (!f.file) {
1324 ret = -EBADF;
1325 goto out;
1326 }
1327
1328 inode = f.file->f_path.dentry->d_inode;
1329 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1330 ret = -EBADF;
1331 goto out_fput;
1332 }
1333 info = MQUEUE_I(inode);
1334
1335 spin_lock(&info->lock);
1336
1337 omqstat = info->attr;
1338 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1339 if (u_mqstat) {
1340 audit_mq_getsetattr(mqdes, &mqstat);
1341 spin_lock(&f.file->f_lock);
1342 if (mqstat.mq_flags & O_NONBLOCK)
1343 f.file->f_flags |= O_NONBLOCK;
1344 else
1345 f.file->f_flags &= ~O_NONBLOCK;
1346 spin_unlock(&f.file->f_lock);
1347
1348 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1349 }
1350
1351 spin_unlock(&info->lock);
1352
1353 ret = 0;
1354 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1355 sizeof(struct mq_attr)))
1356 ret = -EFAULT;
1357
1358 out_fput:
1359 fdput(f);
1360 out:
1361 return ret;
1362 }
1363
1364 static const struct inode_operations mqueue_dir_inode_operations = {
1365 .lookup = simple_lookup,
1366 .create = mqueue_create,
1367 .unlink = mqueue_unlink,
1368 };
1369
1370 static const struct file_operations mqueue_file_operations = {
1371 .flush = mqueue_flush_file,
1372 .poll = mqueue_poll_file,
1373 .read = mqueue_read_file,
1374 .llseek = default_llseek,
1375 };
1376
1377 static const struct super_operations mqueue_super_ops = {
1378 .alloc_inode = mqueue_alloc_inode,
1379 .destroy_inode = mqueue_destroy_inode,
1380 .evict_inode = mqueue_evict_inode,
1381 .statfs = simple_statfs,
1382 };
1383
1384 static struct file_system_type mqueue_fs_type = {
1385 .name = "mqueue",
1386 .mount = mqueue_mount,
1387 .kill_sb = kill_litter_super,
1388 };
1389
1390 int mq_init_ns(struct ipc_namespace *ns)
1391 {
1392 ns->mq_queues_count = 0;
1393 ns->mq_queues_max = DFLT_QUEUESMAX;
1394 ns->mq_msg_max = DFLT_MSGMAX;
1395 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1396 ns->mq_msg_default = DFLT_MSG;
1397 ns->mq_msgsize_default = DFLT_MSGSIZE;
1398
1399 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1400 if (IS_ERR(ns->mq_mnt)) {
1401 int err = PTR_ERR(ns->mq_mnt);
1402 ns->mq_mnt = NULL;
1403 return err;
1404 }
1405 return 0;
1406 }
1407
1408 void mq_clear_sbinfo(struct ipc_namespace *ns)
1409 {
1410 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1411 }
1412
1413 void mq_put_mnt(struct ipc_namespace *ns)
1414 {
1415 kern_unmount(ns->mq_mnt);
1416 }
1417
1418 static int __init init_mqueue_fs(void)
1419 {
1420 int error;
1421
1422 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1423 sizeof(struct mqueue_inode_info), 0,
1424 SLAB_HWCACHE_ALIGN, init_once);
1425 if (mqueue_inode_cachep == NULL)
1426 return -ENOMEM;
1427
1428 /* ignore failures - they are not fatal */
1429 mq_sysctl_table = mq_register_sysctl_table();
1430
1431 error = register_filesystem(&mqueue_fs_type);
1432 if (error)
1433 goto out_sysctl;
1434
1435 spin_lock_init(&mq_lock);
1436
1437 error = mq_init_ns(&init_ipc_ns);
1438 if (error)
1439 goto out_filesystem;
1440
1441 return 0;
1442
1443 out_filesystem:
1444 unregister_filesystem(&mqueue_fs_type);
1445 out_sysctl:
1446 if (mq_sysctl_table)
1447 unregister_sysctl_table(mq_sysctl_table);
1448 kmem_cache_destroy(mqueue_inode_cachep);
1449 return error;
1450 }
1451
1452 __initcall(init_mqueue_fs);
Linux kernel - Deliverables
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