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Linux 4.1.18
[linux/fpc-iii.git] / ipc / mqueue.c
blobc3fc5c2b63f34fb3670ab7be58b11c813c4fbac1
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 INIT_LIST_HEAD(&leaf->msg_list);
146 }
147 leaf->priority = msg->m_type;
148 rb_link_node(&leaf->rb_node, parent, p);
149 rb_insert_color(&leaf->rb_node, &info->msg_tree);
150 insert_msg:
151 info->attr.mq_curmsgs++;
152 info->qsize += msg->m_ts;
153 list_add_tail(&msg->m_list, &leaf->msg_list);
154 return 0;
155 }
156
157 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
158 {
159 struct rb_node **p, *parent = NULL;
160 struct posix_msg_tree_node *leaf;
161 struct msg_msg *msg;
162
163 try_again:
164 p = &info->msg_tree.rb_node;
165 while (*p) {
166 parent = *p;
167 /*
168 * During insert, low priorities go to the left and high to the
169 * right. On receive, we want the highest priorities first, so
170 * walk all the way to the right.
171 */
172 p = &(*p)->rb_right;
173 }
174 if (!parent) {
175 if (info->attr.mq_curmsgs) {
176 pr_warn_once("Inconsistency in POSIX message queue, "
177 "no tree element, but supposedly messages "
178 "should exist!\n");
179 info->attr.mq_curmsgs = 0;
180 }
181 return NULL;
182 }
183 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
184 if (unlikely(list_empty(&leaf->msg_list))) {
185 pr_warn_once("Inconsistency in POSIX message queue, "
186 "empty leaf node but we haven't implemented "
187 "lazy leaf delete!\n");
188 rb_erase(&leaf->rb_node, &info->msg_tree);
189 if (info->node_cache) {
190 kfree(leaf);
191 } else {
192 info->node_cache = leaf;
193 }
194 goto try_again;
195 } else {
196 msg = list_first_entry(&leaf->msg_list,
197 struct msg_msg, m_list);
198 list_del(&msg->m_list);
199 if (list_empty(&leaf->msg_list)) {
200 rb_erase(&leaf->rb_node, &info->msg_tree);
201 if (info->node_cache) {
202 kfree(leaf);
203 } else {
204 info->node_cache = leaf;
205 }
206 }
207 }
208 info->attr.mq_curmsgs--;
209 info->qsize -= msg->m_ts;
210 return msg;
211 }
212
213 static struct inode *mqueue_get_inode(struct super_block *sb,
214 struct ipc_namespace *ipc_ns, umode_t mode,
215 struct mq_attr *attr)
216 {
217 struct user_struct *u = current_user();
218 struct inode *inode;
219 int ret = -ENOMEM;
220
221 inode = new_inode(sb);
222 if (!inode)
223 goto err;
224
225 inode->i_ino = get_next_ino();
226 inode->i_mode = mode;
227 inode->i_uid = current_fsuid();
228 inode->i_gid = current_fsgid();
229 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
230
231 if (S_ISREG(mode)) {
232 struct mqueue_inode_info *info;
233 unsigned long mq_bytes, mq_treesize;
234
235 inode->i_fop = &mqueue_file_operations;
236 inode->i_size = FILENT_SIZE;
237 /* mqueue specific info */
238 info = MQUEUE_I(inode);
239 spin_lock_init(&info->lock);
240 init_waitqueue_head(&info->wait_q);
241 INIT_LIST_HEAD(&info->e_wait_q[0].list);
242 INIT_LIST_HEAD(&info->e_wait_q[1].list);
243 info->notify_owner = NULL;
244 info->notify_user_ns = NULL;
245 info->qsize = 0;
246 info->user = NULL; /* set when all is ok */
247 info->msg_tree = RB_ROOT;
248 info->node_cache = NULL;
249 memset(&info->attr, 0, sizeof(info->attr));
250 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
251 ipc_ns->mq_msg_default);
252 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
253 ipc_ns->mq_msgsize_default);
254 if (attr) {
255 info->attr.mq_maxmsg = attr->mq_maxmsg;
256 info->attr.mq_msgsize = attr->mq_msgsize;
257 }
258 /*
259 * We used to allocate a static array of pointers and account
260 * the size of that array as well as one msg_msg struct per
261 * possible message into the queue size. That's no longer
262 * accurate as the queue is now an rbtree and will grow and
263 * shrink depending on usage patterns. We can, however, still
264 * account one msg_msg struct per message, but the nodes are
265 * allocated depending on priority usage, and most programs
266 * only use one, or a handful, of priorities. However, since
267 * this is pinned memory, we need to assume worst case, so
268 * that means the min(mq_maxmsg, max_priorities) * struct
269 * posix_msg_tree_node.
270 */
271 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
272 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
273 sizeof(struct posix_msg_tree_node);
274
275 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
276 info->attr.mq_msgsize);
277
278 spin_lock(&mq_lock);
279 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
280 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
281 spin_unlock(&mq_lock);
282 /* mqueue_evict_inode() releases info->messages */
283 ret = -EMFILE;
284 goto out_inode;
285 }
286 u->mq_bytes += mq_bytes;
287 spin_unlock(&mq_lock);
288
289 /* all is ok */
290 info->user = get_uid(u);
291 } else if (S_ISDIR(mode)) {
292 inc_nlink(inode);
293 /* Some things misbehave if size == 0 on a directory */
294 inode->i_size = 2 * DIRENT_SIZE;
295 inode->i_op = &mqueue_dir_inode_operations;
296 inode->i_fop = &simple_dir_operations;
297 }
298
299 return inode;
300 out_inode:
301 iput(inode);
302 err:
303 return ERR_PTR(ret);
304 }
305
306 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
307 {
308 struct inode *inode;
309 struct ipc_namespace *ns = data;
310
311 sb->s_blocksize = PAGE_CACHE_SIZE;
312 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
313 sb->s_magic = MQUEUE_MAGIC;
314 sb->s_op = &mqueue_super_ops;
315
316 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
317 if (IS_ERR(inode))
318 return PTR_ERR(inode);
319
320 sb->s_root = d_make_root(inode);
321 if (!sb->s_root)
322 return -ENOMEM;
323 return 0;
324 }
325
326 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
327 int flags, const char *dev_name,
328 void *data)
329 {
330 if (!(flags & MS_KERNMOUNT)) {
331 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
332 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
333 * over the ipc namespace.
334 */
335 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
336 return ERR_PTR(-EPERM);
337
338 data = ns;
339 }
340 return mount_ns(fs_type, flags, data, mqueue_fill_super);
341 }
342
343 static void init_once(void *foo)
344 {
345 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
346
347 inode_init_once(&p->vfs_inode);
348 }
349
350 static struct inode *mqueue_alloc_inode(struct super_block *sb)
351 {
352 struct mqueue_inode_info *ei;
353
354 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
355 if (!ei)
356 return NULL;
357 return &ei->vfs_inode;
358 }
359
360 static void mqueue_i_callback(struct rcu_head *head)
361 {
362 struct inode *inode = container_of(head, struct inode, i_rcu);
363 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
364 }
365
366 static void mqueue_destroy_inode(struct inode *inode)
367 {
368 call_rcu(&inode->i_rcu, mqueue_i_callback);
369 }
370
371 static void mqueue_evict_inode(struct inode *inode)
372 {
373 struct mqueue_inode_info *info;
374 struct user_struct *user;
375 unsigned long mq_bytes, mq_treesize;
376 struct ipc_namespace *ipc_ns;
377 struct msg_msg *msg;
378
379 clear_inode(inode);
380
381 if (S_ISDIR(inode->i_mode))
382 return;
383
384 ipc_ns = get_ns_from_inode(inode);
385 info = MQUEUE_I(inode);
386 spin_lock(&info->lock);
387 while ((msg = msg_get(info)) != NULL)
388 free_msg(msg);
389 kfree(info->node_cache);
390 spin_unlock(&info->lock);
391
392 /* Total amount of bytes accounted for the mqueue */
393 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
394 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
395 sizeof(struct posix_msg_tree_node);
396
397 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
398 info->attr.mq_msgsize);
399
400 user = info->user;
401 if (user) {
402 spin_lock(&mq_lock);
403 user->mq_bytes -= mq_bytes;
404 /*
405 * get_ns_from_inode() ensures that the
406 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
407 * to which we now hold a reference, or it is NULL.
408 * We can't put it here under mq_lock, though.
409 */
410 if (ipc_ns)
411 ipc_ns->mq_queues_count--;
412 spin_unlock(&mq_lock);
413 free_uid(user);
414 }
415 if (ipc_ns)
416 put_ipc_ns(ipc_ns);
417 }
418
419 static int mqueue_create(struct inode *dir, struct dentry *dentry,
420 umode_t mode, bool excl)
421 {
422 struct inode *inode;
423 struct mq_attr *attr = dentry->d_fsdata;
424 int error;
425 struct ipc_namespace *ipc_ns;
426
427 spin_lock(&mq_lock);
428 ipc_ns = __get_ns_from_inode(dir);
429 if (!ipc_ns) {
430 error = -EACCES;
431 goto out_unlock;
432 }
433
434 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
435 !capable(CAP_SYS_RESOURCE)) {
436 error = -ENOSPC;
437 goto out_unlock;
438 }
439 ipc_ns->mq_queues_count++;
440 spin_unlock(&mq_lock);
441
442 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
443 if (IS_ERR(inode)) {
444 error = PTR_ERR(inode);
445 spin_lock(&mq_lock);
446 ipc_ns->mq_queues_count--;
447 goto out_unlock;
448 }
449
450 put_ipc_ns(ipc_ns);
451 dir->i_size += DIRENT_SIZE;
452 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
453
454 d_instantiate(dentry, inode);
455 dget(dentry);
456 return 0;
457 out_unlock:
458 spin_unlock(&mq_lock);
459 if (ipc_ns)
460 put_ipc_ns(ipc_ns);
461 return error;
462 }
463
464 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
465 {
466 struct inode *inode = d_inode(dentry);
467
468 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
469 dir->i_size -= DIRENT_SIZE;
470 drop_nlink(inode);
471 dput(dentry);
472 return 0;
473 }
474
475 /*
476 * This is routine for system read from queue file.
477 * To avoid mess with doing here some sort of mq_receive we allow
478 * to read only queue size & notification info (the only values
479 * that are interesting from user point of view and aren't accessible
480 * through std routines)
481 */
482 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
483 size_t count, loff_t *off)
484 {
485 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
486 char buffer[FILENT_SIZE];
487 ssize_t ret;
488
489 spin_lock(&info->lock);
490 snprintf(buffer, sizeof(buffer),
491 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
492 info->qsize,
493 info->notify_owner ? info->notify.sigev_notify : 0,
494 (info->notify_owner &&
495 info->notify.sigev_notify == SIGEV_SIGNAL) ?
496 info->notify.sigev_signo : 0,
497 pid_vnr(info->notify_owner));
498 spin_unlock(&info->lock);
499 buffer[sizeof(buffer)-1] = '\0';
500
501 ret = simple_read_from_buffer(u_data, count, off, buffer,
502 strlen(buffer));
503 if (ret <= 0)
504 return ret;
505
506 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME;
507 return ret;
508 }
509
510 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
511 {
512 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
513
514 spin_lock(&info->lock);
515 if (task_tgid(current) == info->notify_owner)
516 remove_notification(info);
517
518 spin_unlock(&info->lock);
519 return 0;
520 }
521
522 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
523 {
524 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
525 int retval = 0;
526
527 poll_wait(filp, &info->wait_q, poll_tab);
528
529 spin_lock(&info->lock);
530 if (info->attr.mq_curmsgs)
531 retval = POLLIN | POLLRDNORM;
532
533 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
534 retval |= POLLOUT | POLLWRNORM;
535 spin_unlock(&info->lock);
536
537 return retval;
538 }
539
540 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
541 static void wq_add(struct mqueue_inode_info *info, int sr,
542 struct ext_wait_queue *ewp)
543 {
544 struct ext_wait_queue *walk;
545
546 ewp->task = current;
547
548 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
549 if (walk->task->static_prio <= current->static_prio) {
550 list_add_tail(&ewp->list, &walk->list);
551 return;
552 }
553 }
554 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
555 }
556
557 /*
558 * Puts current task to sleep. Caller must hold queue lock. After return
559 * lock isn't held.
560 * sr: SEND or RECV
561 */
562 static int wq_sleep(struct mqueue_inode_info *info, int sr,
563 ktime_t *timeout, struct ext_wait_queue *ewp)
564 {
565 int retval;
566 signed long time;
567
568 wq_add(info, sr, ewp);
569
570 for (;;) {
571 set_current_state(TASK_INTERRUPTIBLE);
572
573 spin_unlock(&info->lock);
574 time = schedule_hrtimeout_range_clock(timeout, 0,
575 HRTIMER_MODE_ABS, CLOCK_REALTIME);
576
577 while (ewp->state == STATE_PENDING)
578 cpu_relax();
579
580 if (ewp->state == STATE_READY) {
581 retval = 0;
582 goto out;
583 }
584 spin_lock(&info->lock);
585 if (ewp->state == STATE_READY) {
586 retval = 0;
587 goto out_unlock;
588 }
589 if (signal_pending(current)) {
590 retval = -ERESTARTSYS;
591 break;
592 }
593 if (time == 0) {
594 retval = -ETIMEDOUT;
595 break;
596 }
597 }
598 list_del(&ewp->list);
599 out_unlock:
600 spin_unlock(&info->lock);
601 out:
602 return retval;
603 }
604
605 /*
606 * Returns waiting task that should be serviced first or NULL if none exists
607 */
608 static struct ext_wait_queue *wq_get_first_waiter(
609 struct mqueue_inode_info *info, int sr)
610 {
611 struct list_head *ptr;
612
613 ptr = info->e_wait_q[sr].list.prev;
614 if (ptr == &info->e_wait_q[sr].list)
615 return NULL;
616 return list_entry(ptr, struct ext_wait_queue, list);
617 }
618
619
620 static inline void set_cookie(struct sk_buff *skb, char code)
621 {
622 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
623 }
624
625 /*
626 * The next function is only to split too long sys_mq_timedsend
627 */
628 static void __do_notify(struct mqueue_inode_info *info)
629 {
630 /* notification
631 * invoked when there is registered process and there isn't process
632 * waiting synchronously for message AND state of queue changed from
633 * empty to not empty. Here we are sure that no one is waiting
634 * synchronously. */
635 if (info->notify_owner &&
636 info->attr.mq_curmsgs == 1) {
637 struct siginfo sig_i;
638 switch (info->notify.sigev_notify) {
639 case SIGEV_NONE:
640 break;
641 case SIGEV_SIGNAL:
642 /* sends signal */
643
644 sig_i.si_signo = info->notify.sigev_signo;
645 sig_i.si_errno = 0;
646 sig_i.si_code = SI_MESGQ;
647 sig_i.si_value = info->notify.sigev_value;
648 /* map current pid/uid into info->owner's namespaces */
649 rcu_read_lock();
650 sig_i.si_pid = task_tgid_nr_ns(current,
651 ns_of_pid(info->notify_owner));
652 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
653 rcu_read_unlock();
654
655 kill_pid_info(info->notify.sigev_signo,
656 &sig_i, info->notify_owner);
657 break;
658 case SIGEV_THREAD:
659 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
660 netlink_sendskb(info->notify_sock, info->notify_cookie);
661 break;
662 }
663 /* after notification unregisters process */
664 put_pid(info->notify_owner);
665 put_user_ns(info->notify_user_ns);
666 info->notify_owner = NULL;
667 info->notify_user_ns = NULL;
668 }
669 wake_up(&info->wait_q);
670 }
671
672 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
673 ktime_t *expires, struct timespec *ts)
674 {
675 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
676 return -EFAULT;
677 if (!timespec_valid(ts))
678 return -EINVAL;
679
680 *expires = timespec_to_ktime(*ts);
681 return 0;
682 }
683
684 static void remove_notification(struct mqueue_inode_info *info)
685 {
686 if (info->notify_owner != NULL &&
687 info->notify.sigev_notify == SIGEV_THREAD) {
688 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
689 netlink_sendskb(info->notify_sock, info->notify_cookie);
690 }
691 put_pid(info->notify_owner);
692 put_user_ns(info->notify_user_ns);
693 info->notify_owner = NULL;
694 info->notify_user_ns = NULL;
695 }
696
697 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
698 {
699 int mq_treesize;
700 unsigned long total_size;
701
702 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
703 return -EINVAL;
704 if (capable(CAP_SYS_RESOURCE)) {
705 if (attr->mq_maxmsg > HARD_MSGMAX ||
706 attr->mq_msgsize > HARD_MSGSIZEMAX)
707 return -EINVAL;
708 } else {
709 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
710 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
711 return -EINVAL;
712 }
713 /* check for overflow */
714 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
715 return -EOVERFLOW;
716 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
717 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
718 sizeof(struct posix_msg_tree_node);
719 total_size = attr->mq_maxmsg * attr->mq_msgsize;
720 if (total_size + mq_treesize < total_size)
721 return -EOVERFLOW;
722 return 0;
723 }
724
725 /*
726 * Invoked when creating a new queue via sys_mq_open
727 */
728 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
729 struct path *path, int oflag, umode_t mode,
730 struct mq_attr *attr)
731 {
732 const struct cred *cred = current_cred();
733 int ret;
734
735 if (attr) {
736 ret = mq_attr_ok(ipc_ns, attr);
737 if (ret)
738 return ERR_PTR(ret);
739 /* store for use during create */
740 path->dentry->d_fsdata = attr;
741 } else {
742 struct mq_attr def_attr;
743
744 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
745 ipc_ns->mq_msg_default);
746 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
747 ipc_ns->mq_msgsize_default);
748 ret = mq_attr_ok(ipc_ns, &def_attr);
749 if (ret)
750 return ERR_PTR(ret);
751 }
752
753 mode &= ~current_umask();
754 ret = vfs_create(dir, path->dentry, mode, true);
755 path->dentry->d_fsdata = NULL;
756 if (ret)
757 return ERR_PTR(ret);
758 return dentry_open(path, oflag, cred);
759 }
760
761 /* Opens existing queue */
762 static struct file *do_open(struct path *path, int oflag)
763 {
764 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
765 MAY_READ | MAY_WRITE };
766 int acc;
767 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
768 return ERR_PTR(-EINVAL);
769 acc = oflag2acc[oflag & O_ACCMODE];
770 if (inode_permission(d_inode(path->dentry), acc))
771 return ERR_PTR(-EACCES);
772 return dentry_open(path, oflag, current_cred());
773 }
774
775 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
776 struct mq_attr __user *, u_attr)
777 {
778 struct path path;
779 struct file *filp;
780 struct filename *name;
781 struct mq_attr attr;
782 int fd, error;
783 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
784 struct vfsmount *mnt = ipc_ns->mq_mnt;
785 struct dentry *root = mnt->mnt_root;
786 int ro;
787
788 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
789 return -EFAULT;
790
791 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
792
793 if (IS_ERR(name = getname(u_name)))
794 return PTR_ERR(name);
795
796 fd = get_unused_fd_flags(O_CLOEXEC);
797 if (fd < 0)
798 goto out_putname;
799
800 ro = mnt_want_write(mnt); /* we'll drop it in any case */
801 error = 0;
802 mutex_lock(&d_inode(root)->i_mutex);
803 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
804 if (IS_ERR(path.dentry)) {
805 error = PTR_ERR(path.dentry);
806 goto out_putfd;
807 }
808 path.mnt = mntget(mnt);
809
810 if (oflag & O_CREAT) {
811 if (d_really_is_positive(path.dentry)) { /* entry already exists */
812 audit_inode(name, path.dentry, 0);
813 if (oflag & O_EXCL) {
814 error = -EEXIST;
815 goto out;
816 }
817 filp = do_open(&path, oflag);
818 } else {
819 if (ro) {
820 error = ro;
821 goto out;
822 }
823 audit_inode_parent_hidden(name, root);
824 filp = do_create(ipc_ns, d_inode(root),
825 &path, oflag, mode,
826 u_attr ? &attr : NULL);
827 }
828 } else {
829 if (d_really_is_negative(path.dentry)) {
830 error = -ENOENT;
831 goto out;
832 }
833 audit_inode(name, path.dentry, 0);
834 filp = do_open(&path, oflag);
835 }
836
837 if (!IS_ERR(filp))
838 fd_install(fd, filp);
839 else
840 error = PTR_ERR(filp);
841 out:
842 path_put(&path);
843 out_putfd:
844 if (error) {
845 put_unused_fd(fd);
846 fd = error;
847 }
848 mutex_unlock(&d_inode(root)->i_mutex);
849 if (!ro)
850 mnt_drop_write(mnt);
851 out_putname:
852 putname(name);
853 return fd;
854 }
855
856 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
857 {
858 int err;
859 struct filename *name;
860 struct dentry *dentry;
861 struct inode *inode = NULL;
862 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
863 struct vfsmount *mnt = ipc_ns->mq_mnt;
864
865 name = getname(u_name);
866 if (IS_ERR(name))
867 return PTR_ERR(name);
868
869 audit_inode_parent_hidden(name, mnt->mnt_root);
870 err = mnt_want_write(mnt);
871 if (err)
872 goto out_name;
873 mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT);
874 dentry = lookup_one_len(name->name, mnt->mnt_root,
875 strlen(name->name));
876 if (IS_ERR(dentry)) {
877 err = PTR_ERR(dentry);
878 goto out_unlock;
879 }
880
881 inode = d_inode(dentry);
882 if (!inode) {
883 err = -ENOENT;
884 } else {
885 ihold(inode);
886 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
887 }
888 dput(dentry);
889
890 out_unlock:
891 mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex);
892 if (inode)
893 iput(inode);
894 mnt_drop_write(mnt);
895 out_name:
896 putname(name);
897
898 return err;
899 }
900
901 /* Pipelined send and receive functions.
902 *
903 * If a receiver finds no waiting message, then it registers itself in the
904 * list of waiting receivers. A sender checks that list before adding the new
905 * message into the message array. If there is a waiting receiver, then it
906 * bypasses the message array and directly hands the message over to the
907 * receiver.
908 * The receiver accepts the message and returns without grabbing the queue
909 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
910 * are necessary. The same algorithm is used for sysv semaphores, see
911 * ipc/sem.c for more details.
912 *
913 * The same algorithm is used for senders.
914 */
915
916 /* pipelined_send() - send a message directly to the task waiting in
917 * sys_mq_timedreceive() (without inserting message into a queue).
918 */
919 static inline void pipelined_send(struct mqueue_inode_info *info,
920 struct msg_msg *message,
921 struct ext_wait_queue *receiver)
922 {
923 receiver->msg = message;
924 list_del(&receiver->list);
925 receiver->state = STATE_PENDING;
926 wake_up_process(receiver->task);
927 smp_wmb();
928 receiver->state = STATE_READY;
929 }
930
931 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
932 * gets its message and put to the queue (we have one free place for sure). */
933 static inline void pipelined_receive(struct mqueue_inode_info *info)
934 {
935 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
936
937 if (!sender) {
938 /* for poll */
939 wake_up_interruptible(&info->wait_q);
940 return;
941 }
942 if (msg_insert(sender->msg, info))
943 return;
944 list_del(&sender->list);
945 sender->state = STATE_PENDING;
946 wake_up_process(sender->task);
947 smp_wmb();
948 sender->state = STATE_READY;
949 }
950
951 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
952 size_t, msg_len, unsigned int, msg_prio,
953 const struct timespec __user *, u_abs_timeout)
954 {
955 struct fd f;
956 struct inode *inode;
957 struct ext_wait_queue wait;
958 struct ext_wait_queue *receiver;
959 struct msg_msg *msg_ptr;
960 struct mqueue_inode_info *info;
961 ktime_t expires, *timeout = NULL;
962 struct timespec ts;
963 struct posix_msg_tree_node *new_leaf = NULL;
964 int ret = 0;
965
966 if (u_abs_timeout) {
967 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
968 if (res)
969 return res;
970 timeout = &expires;
971 }
972
973 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
974 return -EINVAL;
975
976 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
977
978 f = fdget(mqdes);
979 if (unlikely(!f.file)) {
980 ret = -EBADF;
981 goto out;
982 }
983
984 inode = file_inode(f.file);
985 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
986 ret = -EBADF;
987 goto out_fput;
988 }
989 info = MQUEUE_I(inode);
990 audit_file(f.file);
991
992 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
993 ret = -EBADF;
994 goto out_fput;
995 }
996
997 if (unlikely(msg_len > info->attr.mq_msgsize)) {
998 ret = -EMSGSIZE;
999 goto out_fput;
1000 }
1001
1002 /* First try to allocate memory, before doing anything with
1003 * existing queues. */
1004 msg_ptr = load_msg(u_msg_ptr, msg_len);
1005 if (IS_ERR(msg_ptr)) {
1006 ret = PTR_ERR(msg_ptr);
1007 goto out_fput;
1008 }
1009 msg_ptr->m_ts = msg_len;
1010 msg_ptr->m_type = msg_prio;
1011
1012 /*
1013 * msg_insert really wants us to have a valid, spare node struct so
1014 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1015 * fall back to that if necessary.
1016 */
1017 if (!info->node_cache)
1018 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1019
1020 spin_lock(&info->lock);
1021
1022 if (!info->node_cache && new_leaf) {
1023 /* Save our speculative allocation into the cache */
1024 INIT_LIST_HEAD(&new_leaf->msg_list);
1025 info->node_cache = new_leaf;
1026 new_leaf = NULL;
1027 } else {
1028 kfree(new_leaf);
1029 }
1030
1031 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1032 if (f.file->f_flags & O_NONBLOCK) {
1033 ret = -EAGAIN;
1034 } else {
1035 wait.task = current;
1036 wait.msg = (void *) msg_ptr;
1037 wait.state = STATE_NONE;
1038 ret = wq_sleep(info, SEND, timeout, &wait);
1039 /*
1040 * wq_sleep must be called with info->lock held, and
1041 * returns with the lock released
1042 */
1043 goto out_free;
1044 }
1045 } else {
1046 receiver = wq_get_first_waiter(info, RECV);
1047 if (receiver) {
1048 pipelined_send(info, msg_ptr, receiver);
1049 } else {
1050 /* adds message to the queue */
1051 ret = msg_insert(msg_ptr, info);
1052 if (ret)
1053 goto out_unlock;
1054 __do_notify(info);
1055 }
1056 inode->i_atime = inode->i_mtime = inode->i_ctime =
1057 CURRENT_TIME;
1058 }
1059 out_unlock:
1060 spin_unlock(&info->lock);
1061 out_free:
1062 if (ret)
1063 free_msg(msg_ptr);
1064 out_fput:
1065 fdput(f);
1066 out:
1067 return ret;
1068 }
1069
1070 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1071 size_t, msg_len, unsigned int __user *, u_msg_prio,
1072 const struct timespec __user *, u_abs_timeout)
1073 {
1074 ssize_t ret;
1075 struct msg_msg *msg_ptr;
1076 struct fd f;
1077 struct inode *inode;
1078 struct mqueue_inode_info *info;
1079 struct ext_wait_queue wait;
1080 ktime_t expires, *timeout = NULL;
1081 struct timespec ts;
1082 struct posix_msg_tree_node *new_leaf = NULL;
1083
1084 if (u_abs_timeout) {
1085 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1086 if (res)
1087 return res;
1088 timeout = &expires;
1089 }
1090
1091 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1092
1093 f = fdget(mqdes);
1094 if (unlikely(!f.file)) {
1095 ret = -EBADF;
1096 goto out;
1097 }
1098
1099 inode = file_inode(f.file);
1100 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1101 ret = -EBADF;
1102 goto out_fput;
1103 }
1104 info = MQUEUE_I(inode);
1105 audit_file(f.file);
1106
1107 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1108 ret = -EBADF;
1109 goto out_fput;
1110 }
1111
1112 /* checks if buffer is big enough */
1113 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1114 ret = -EMSGSIZE;
1115 goto out_fput;
1116 }
1117
1118 /*
1119 * msg_insert really wants us to have a valid, spare node struct so
1120 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1121 * fall back to that if necessary.
1122 */
1123 if (!info->node_cache)
1124 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1125
1126 spin_lock(&info->lock);
1127
1128 if (!info->node_cache && new_leaf) {
1129 /* Save our speculative allocation into the cache */
1130 INIT_LIST_HEAD(&new_leaf->msg_list);
1131 info->node_cache = new_leaf;
1132 } else {
1133 kfree(new_leaf);
1134 }
1135
1136 if (info->attr.mq_curmsgs == 0) {
1137 if (f.file->f_flags & O_NONBLOCK) {
1138 spin_unlock(&info->lock);
1139 ret = -EAGAIN;
1140 } else {
1141 wait.task = current;
1142 wait.state = STATE_NONE;
1143 ret = wq_sleep(info, RECV, timeout, &wait);
1144 msg_ptr = wait.msg;
1145 }
1146 } else {
1147 msg_ptr = msg_get(info);
1148
1149 inode->i_atime = inode->i_mtime = inode->i_ctime =
1150 CURRENT_TIME;
1151
1152 /* There is now free space in queue. */
1153 pipelined_receive(info);
1154 spin_unlock(&info->lock);
1155 ret = 0;
1156 }
1157 if (ret == 0) {
1158 ret = msg_ptr->m_ts;
1159
1160 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1161 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1162 ret = -EFAULT;
1163 }
1164 free_msg(msg_ptr);
1165 }
1166 out_fput:
1167 fdput(f);
1168 out:
1169 return ret;
1170 }
1171
1172 /*
1173 * Notes: the case when user wants us to deregister (with NULL as pointer)
1174 * and he isn't currently owner of notification, will be silently discarded.
1175 * It isn't explicitly defined in the POSIX.
1176 */
1177 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1178 const struct sigevent __user *, u_notification)
1179 {
1180 int ret;
1181 struct fd f;
1182 struct sock *sock;
1183 struct inode *inode;
1184 struct sigevent notification;
1185 struct mqueue_inode_info *info;
1186 struct sk_buff *nc;
1187
1188 if (u_notification) {
1189 if (copy_from_user(&notification, u_notification,
1190 sizeof(struct sigevent)))
1191 return -EFAULT;
1192 }
1193
1194 audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1195
1196 nc = NULL;
1197 sock = NULL;
1198 if (u_notification != NULL) {
1199 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1200 notification.sigev_notify != SIGEV_SIGNAL &&
1201 notification.sigev_notify != SIGEV_THREAD))
1202 return -EINVAL;
1203 if (notification.sigev_notify == SIGEV_SIGNAL &&
1204 !valid_signal(notification.sigev_signo)) {
1205 return -EINVAL;
1206 }
1207 if (notification.sigev_notify == SIGEV_THREAD) {
1208 long timeo;
1209
1210 /* create the notify skb */
1211 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1212 if (!nc) {
1213 ret = -ENOMEM;
1214 goto out;
1215 }
1216 if (copy_from_user(nc->data,
1217 notification.sigev_value.sival_ptr,
1218 NOTIFY_COOKIE_LEN)) {
1219 ret = -EFAULT;
1220 goto out;
1221 }
1222
1223 /* TODO: add a header? */
1224 skb_put(nc, NOTIFY_COOKIE_LEN);
1225 /* and attach it to the socket */
1226 retry:
1227 f = fdget(notification.sigev_signo);
1228 if (!f.file) {
1229 ret = -EBADF;
1230 goto out;
1231 }
1232 sock = netlink_getsockbyfilp(f.file);
1233 fdput(f);
1234 if (IS_ERR(sock)) {
1235 ret = PTR_ERR(sock);
1236 sock = NULL;
1237 goto out;
1238 }
1239
1240 timeo = MAX_SCHEDULE_TIMEOUT;
1241 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1242 if (ret == 1)
1243 goto retry;
1244 if (ret) {
1245 sock = NULL;
1246 nc = NULL;
1247 goto out;
1248 }
1249 }
1250 }
1251
1252 f = fdget(mqdes);
1253 if (!f.file) {
1254 ret = -EBADF;
1255 goto out;
1256 }
1257
1258 inode = file_inode(f.file);
1259 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1260 ret = -EBADF;
1261 goto out_fput;
1262 }
1263 info = MQUEUE_I(inode);
1264
1265 ret = 0;
1266 spin_lock(&info->lock);
1267 if (u_notification == NULL) {
1268 if (info->notify_owner == task_tgid(current)) {
1269 remove_notification(info);
1270 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1271 }
1272 } else if (info->notify_owner != NULL) {
1273 ret = -EBUSY;
1274 } else {
1275 switch (notification.sigev_notify) {
1276 case SIGEV_NONE:
1277 info->notify.sigev_notify = SIGEV_NONE;
1278 break;
1279 case SIGEV_THREAD:
1280 info->notify_sock = sock;
1281 info->notify_cookie = nc;
1282 sock = NULL;
1283 nc = NULL;
1284 info->notify.sigev_notify = SIGEV_THREAD;
1285 break;
1286 case SIGEV_SIGNAL:
1287 info->notify.sigev_signo = notification.sigev_signo;
1288 info->notify.sigev_value = notification.sigev_value;
1289 info->notify.sigev_notify = SIGEV_SIGNAL;
1290 break;
1291 }
1292
1293 info->notify_owner = get_pid(task_tgid(current));
1294 info->notify_user_ns = get_user_ns(current_user_ns());
1295 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1296 }
1297 spin_unlock(&info->lock);
1298 out_fput:
1299 fdput(f);
1300 out:
1301 if (sock)
1302 netlink_detachskb(sock, nc);
1303 else if (nc)
1304 dev_kfree_skb(nc);
1305
1306 return ret;
1307 }
1308
1309 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1310 const struct mq_attr __user *, u_mqstat,
1311 struct mq_attr __user *, u_omqstat)
1312 {
1313 int ret;
1314 struct mq_attr mqstat, omqstat;
1315 struct fd f;
1316 struct inode *inode;
1317 struct mqueue_inode_info *info;
1318
1319 if (u_mqstat != NULL) {
1320 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1321 return -EFAULT;
1322 if (mqstat.mq_flags & (~O_NONBLOCK))
1323 return -EINVAL;
1324 }
1325
1326 f = fdget(mqdes);
1327 if (!f.file) {
1328 ret = -EBADF;
1329 goto out;
1330 }
1331
1332 inode = file_inode(f.file);
1333 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1334 ret = -EBADF;
1335 goto out_fput;
1336 }
1337 info = MQUEUE_I(inode);
1338
1339 spin_lock(&info->lock);
1340
1341 omqstat = info->attr;
1342 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1343 if (u_mqstat) {
1344 audit_mq_getsetattr(mqdes, &mqstat);
1345 spin_lock(&f.file->f_lock);
1346 if (mqstat.mq_flags & O_NONBLOCK)
1347 f.file->f_flags |= O_NONBLOCK;
1348 else
1349 f.file->f_flags &= ~O_NONBLOCK;
1350 spin_unlock(&f.file->f_lock);
1351
1352 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1353 }
1354
1355 spin_unlock(&info->lock);
1356
1357 ret = 0;
1358 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1359 sizeof(struct mq_attr)))
1360 ret = -EFAULT;
1361
1362 out_fput:
1363 fdput(f);
1364 out:
1365 return ret;
1366 }
1367
1368 static const struct inode_operations mqueue_dir_inode_operations = {
1369 .lookup = simple_lookup,
1370 .create = mqueue_create,
1371 .unlink = mqueue_unlink,
1372 };
1373
1374 static const struct file_operations mqueue_file_operations = {
1375 .flush = mqueue_flush_file,
1376 .poll = mqueue_poll_file,
1377 .read = mqueue_read_file,
1378 .llseek = default_llseek,
1379 };
1380
1381 static const struct super_operations mqueue_super_ops = {
1382 .alloc_inode = mqueue_alloc_inode,
1383 .destroy_inode = mqueue_destroy_inode,
1384 .evict_inode = mqueue_evict_inode,
1385 .statfs = simple_statfs,
1386 };
1387
1388 static struct file_system_type mqueue_fs_type = {
1389 .name = "mqueue",
1390 .mount = mqueue_mount,
1391 .kill_sb = kill_litter_super,
1392 .fs_flags = FS_USERNS_MOUNT,
1393 };
1394
1395 int mq_init_ns(struct ipc_namespace *ns)
1396 {
1397 ns->mq_queues_count = 0;
1398 ns->mq_queues_max = DFLT_QUEUESMAX;
1399 ns->mq_msg_max = DFLT_MSGMAX;
1400 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1401 ns->mq_msg_default = DFLT_MSG;
1402 ns->mq_msgsize_default = DFLT_MSGSIZE;
1403
1404 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1405 if (IS_ERR(ns->mq_mnt)) {
1406 int err = PTR_ERR(ns->mq_mnt);
1407 ns->mq_mnt = NULL;
1408 return err;
1409 }
1410 return 0;
1411 }
1412
1413 void mq_clear_sbinfo(struct ipc_namespace *ns)
1414 {
1415 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1416 }
1417
1418 void mq_put_mnt(struct ipc_namespace *ns)
1419 {
1420 kern_unmount(ns->mq_mnt);
1421 }
1422
1423 static int __init init_mqueue_fs(void)
1424 {
1425 int error;
1426
1427 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1428 sizeof(struct mqueue_inode_info), 0,
1429 SLAB_HWCACHE_ALIGN, init_once);
1430 if (mqueue_inode_cachep == NULL)
1431 return -ENOMEM;
1432
1433 /* ignore failures - they are not fatal */
1434 mq_sysctl_table = mq_register_sysctl_table();
1435
1436 error = register_filesystem(&mqueue_fs_type);
1437 if (error)
1438 goto out_sysctl;
1439
1440 spin_lock_init(&mq_lock);
1441
1442 error = mq_init_ns(&init_ipc_ns);
1443 if (error)
1444 goto out_filesystem;
1445
1446 return 0;
1447
1448 out_filesystem:
1449 unregister_filesystem(&mqueue_fs_type);
1450 out_sysctl:
1451 if (mq_sysctl_table)
1452 unregister_sysctl_table(mq_sysctl_table);
1453 kmem_cache_destroy(mqueue_inode_cachep);
1454 return error;
1455 }
1456
1457 device_initcall(init_mqueue_fs);
Linux with added FPC-III support