Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/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_READY     1
 51 
 52 struct posix_msg_tree_node {
 53         struct rb_node          rb_node;
 54         struct list_head        msg_list;
 55         int                     priority;
 56 };
 57 
 58 struct ext_wait_queue {         /* queue of sleeping tasks */
 59         struct task_struct *task;
 60         struct list_head list;
 61         struct msg_msg *msg;    /* ptr of loaded message */
 62         int state;              /* one of STATE_* values */
 63 };
 64 
 65 struct mqueue_inode_info {
 66         spinlock_t lock;
 67         struct inode vfs_inode;
 68         wait_queue_head_t wait_q;
 69 
 70         struct rb_root msg_tree;
 71         struct posix_msg_tree_node *node_cache;
 72         struct mq_attr attr;
 73 
 74         struct sigevent notify;
 75         struct pid *notify_owner;
 76         struct user_namespace *notify_user_ns;
 77         struct user_struct *user;       /* user who created, for accounting */
 78         struct sock *notify_sock;
 79         struct sk_buff *notify_cookie;
 80 
 81         /* for tasks waiting for free space and messages, respectively */
 82         struct ext_wait_queue e_wait_q[2];
 83 
 84         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
 85 };
 86 
 87 static const struct inode_operations mqueue_dir_inode_operations;
 88 static const struct file_operations mqueue_file_operations;
 89 static const struct super_operations mqueue_super_ops;
 90 static void remove_notification(struct mqueue_inode_info *info);
 91 
 92 static struct kmem_cache *mqueue_inode_cachep;
 93 
 94 static struct ctl_table_header *mq_sysctl_table;
 95 
 96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
 97 {
 98         return container_of(inode, struct mqueue_inode_info, vfs_inode);
 99 }
100 
101 /*
102  * This routine should be called with the mq_lock held.
103  */
104 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
105 {
106         return get_ipc_ns(inode->i_sb->s_fs_info);
107 }
108 
109 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
110 {
111         struct ipc_namespace *ns;
112 
113         spin_lock(&mq_lock);
114         ns = __get_ns_from_inode(inode);
115         spin_unlock(&mq_lock);
116         return ns;
117 }
118 
119 /* Auxiliary functions to manipulate messages' list */
120 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
121 {
122         struct rb_node **p, *parent = NULL;
123         struct posix_msg_tree_node *leaf;
124 
125         p = &info->msg_tree.rb_node;
126         while (*p) {
127                 parent = *p;
128                 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
129 
130                 if (likely(leaf->priority == msg->m_type))
131                         goto insert_msg;
132                 else if (msg->m_type < leaf->priority)
133                         p = &(*p)->rb_left;
134                 else
135                         p = &(*p)->rb_right;
136         }
137         if (info->node_cache) {
138                 leaf = info->node_cache;
139                 info->node_cache = NULL;
140         } else {
141                 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
142                 if (!leaf)
143                         return -ENOMEM;
144                 INIT_LIST_HEAD(&leaf->msg_list);
145         }
146         leaf->priority = msg->m_type;
147         rb_link_node(&leaf->rb_node, parent, p);
148         rb_insert_color(&leaf->rb_node, &info->msg_tree);
149 insert_msg:
150         info->attr.mq_curmsgs++;
151         info->qsize += msg->m_ts;
152         list_add_tail(&msg->m_list, &leaf->msg_list);
153         return 0;
154 }
155 
156 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
157 {
158         struct rb_node **p, *parent = NULL;
159         struct posix_msg_tree_node *leaf;
160         struct msg_msg *msg;
161 
162 try_again:
163         p = &info->msg_tree.rb_node;
164         while (*p) {
165                 parent = *p;
166                 /*
167                  * During insert, low priorities go to the left and high to the
168                  * right.  On receive, we want the highest priorities first, so
169                  * walk all the way to the right.
170                  */
171                 p = &(*p)->rb_right;
172         }
173         if (!parent) {
174                 if (info->attr.mq_curmsgs) {
175                         pr_warn_once("Inconsistency in POSIX message queue, "
176                                      "no tree element, but supposedly messages "
177                                      "should exist!\n");
178                         info->attr.mq_curmsgs = 0;
179                 }
180                 return NULL;
181         }
182         leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
183         if (unlikely(list_empty(&leaf->msg_list))) {
184                 pr_warn_once("Inconsistency in POSIX message queue, "
185                              "empty leaf node but we haven't implemented "
186                              "lazy leaf delete!\n");
187                 rb_erase(&leaf->rb_node, &info->msg_tree);
188                 if (info->node_cache) {
189                         kfree(leaf);
190                 } else {
191                         info->node_cache = leaf;
192                 }
193                 goto try_again;
194         } else {
195                 msg = list_first_entry(&leaf->msg_list,
196                                        struct msg_msg, m_list);
197                 list_del(&msg->m_list);
198                 if (list_empty(&leaf->msg_list)) {
199                         rb_erase(&leaf->rb_node, &info->msg_tree);
200                         if (info->node_cache) {
201                                 kfree(leaf);
202                         } else {
203                                 info->node_cache = leaf;
204                         }
205                 }
206         }
207         info->attr.mq_curmsgs--;
208         info->qsize -= msg->m_ts;
209         return msg;
210 }
211 
212 static struct inode *mqueue_get_inode(struct super_block *sb,
213                 struct ipc_namespace *ipc_ns, umode_t mode,
214                 struct mq_attr *attr)
215 {
216         struct user_struct *u = current_user();
217         struct inode *inode;
218         int ret = -ENOMEM;
219 
220         inode = new_inode(sb);
221         if (!inode)
222                 goto err;
223 
224         inode->i_ino = get_next_ino();
225         inode->i_mode = mode;
226         inode->i_uid = current_fsuid();
227         inode->i_gid = current_fsgid();
228         inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
229 
230         if (S_ISREG(mode)) {
231                 struct mqueue_inode_info *info;
232                 unsigned long mq_bytes, mq_treesize;
233 
234                 inode->i_fop = &mqueue_file_operations;
235                 inode->i_size = FILENT_SIZE;
236                 /* mqueue specific info */
237                 info = MQUEUE_I(inode);
238                 spin_lock_init(&info->lock);
239                 init_waitqueue_head(&info->wait_q);
240                 INIT_LIST_HEAD(&info->e_wait_q[0].list);
241                 INIT_LIST_HEAD(&info->e_wait_q[1].list);
242                 info->notify_owner = NULL;
243                 info->notify_user_ns = NULL;
244                 info->qsize = 0;
245                 info->user = NULL;      /* set when all is ok */
246                 info->msg_tree = RB_ROOT;
247                 info->node_cache = NULL;
248                 memset(&info->attr, 0, sizeof(info->attr));
249                 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
250                                            ipc_ns->mq_msg_default);
251                 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
252                                             ipc_ns->mq_msgsize_default);
253                 if (attr) {
254                         info->attr.mq_maxmsg = attr->mq_maxmsg;
255                         info->attr.mq_msgsize = attr->mq_msgsize;
256                 }
257                 /*
258                  * We used to allocate a static array of pointers and account
259                  * the size of that array as well as one msg_msg struct per
260                  * possible message into the queue size. That's no longer
261                  * accurate as the queue is now an rbtree and will grow and
262                  * shrink depending on usage patterns.  We can, however, still
263                  * account one msg_msg struct per message, but the nodes are
264                  * allocated depending on priority usage, and most programs
265                  * only use one, or a handful, of priorities.  However, since
266                  * this is pinned memory, we need to assume worst case, so
267                  * that means the min(mq_maxmsg, max_priorities) * struct
268                  * posix_msg_tree_node.
269                  */
270                 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
271                         min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
272                         sizeof(struct posix_msg_tree_node);
273 
274                 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
275                                           info->attr.mq_msgsize);
276 
277                 spin_lock(&mq_lock);
278                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
279                     u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
280                         spin_unlock(&mq_lock);
281                         /* mqueue_evict_inode() releases info->messages */
282                         ret = -EMFILE;
283                         goto out_inode;
284                 }
285                 u->mq_bytes += mq_bytes;
286                 spin_unlock(&mq_lock);
287 
288                 /* all is ok */
289                 info->user = get_uid(u);
290         } else if (S_ISDIR(mode)) {
291                 inc_nlink(inode);
292                 /* Some things misbehave if size == 0 on a directory */
293                 inode->i_size = 2 * DIRENT_SIZE;
294                 inode->i_op = &mqueue_dir_inode_operations;
295                 inode->i_fop = &simple_dir_operations;
296         }
297 
298         return inode;
299 out_inode:
300         iput(inode);
301 err:
302         return ERR_PTR(ret);
303 }
304 
305 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
306 {
307         struct inode *inode;
308         struct ipc_namespace *ns = sb->s_fs_info;
309 
310         sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
311         sb->s_blocksize = PAGE_SIZE;
312         sb->s_blocksize_bits = PAGE_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         struct ipc_namespace *ns;
331         if (flags & MS_KERNMOUNT) {
332                 ns = data;
333                 data = NULL;
334         } else {
335                 ns = current->nsproxy->ipc_ns;
336         }
337         return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
338 }
339 
340 static void init_once(void *foo)
341 {
342         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
343 
344         inode_init_once(&p->vfs_inode);
345 }
346 
347 static struct inode *mqueue_alloc_inode(struct super_block *sb)
348 {
349         struct mqueue_inode_info *ei;
350 
351         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
352         if (!ei)
353                 return NULL;
354         return &ei->vfs_inode;
355 }
356 
357 static void mqueue_i_callback(struct rcu_head *head)
358 {
359         struct inode *inode = container_of(head, struct inode, i_rcu);
360         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
361 }
362 
363 static void mqueue_destroy_inode(struct inode *inode)
364 {
365         call_rcu(&inode->i_rcu, mqueue_i_callback);
366 }
367 
368 static void mqueue_evict_inode(struct inode *inode)
369 {
370         struct mqueue_inode_info *info;
371         struct user_struct *user;
372         unsigned long mq_bytes, mq_treesize;
373         struct ipc_namespace *ipc_ns;
374         struct msg_msg *msg;
375 
376         clear_inode(inode);
377 
378         if (S_ISDIR(inode->i_mode))
379                 return;
380 
381         ipc_ns = get_ns_from_inode(inode);
382         info = MQUEUE_I(inode);
383         spin_lock(&info->lock);
384         while ((msg = msg_get(info)) != NULL)
385                 free_msg(msg);
386         kfree(info->node_cache);
387         spin_unlock(&info->lock);
388 
389         /* Total amount of bytes accounted for the mqueue */
390         mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
391                 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
392                 sizeof(struct posix_msg_tree_node);
393 
394         mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
395                                   info->attr.mq_msgsize);
396 
397         user = info->user;
398         if (user) {
399                 spin_lock(&mq_lock);
400                 user->mq_bytes -= mq_bytes;
401                 /*
402                  * get_ns_from_inode() ensures that the
403                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
404                  * to which we now hold a reference, or it is NULL.
405                  * We can't put it here under mq_lock, though.
406                  */
407                 if (ipc_ns)
408                         ipc_ns->mq_queues_count--;
409                 spin_unlock(&mq_lock);
410                 free_uid(user);
411         }
412         if (ipc_ns)
413                 put_ipc_ns(ipc_ns);
414 }
415 
416 static int mqueue_create(struct inode *dir, struct dentry *dentry,
417                                 umode_t mode, bool excl)
418 {
419         struct inode *inode;
420         struct mq_attr *attr = dentry->d_fsdata;
421         int error;
422         struct ipc_namespace *ipc_ns;
423 
424         spin_lock(&mq_lock);
425         ipc_ns = __get_ns_from_inode(dir);
426         if (!ipc_ns) {
427                 error = -EACCES;
428                 goto out_unlock;
429         }
430 
431         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
432             !capable(CAP_SYS_RESOURCE)) {
433                 error = -ENOSPC;
434                 goto out_unlock;
435         }
436         ipc_ns->mq_queues_count++;
437         spin_unlock(&mq_lock);
438 
439         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
440         if (IS_ERR(inode)) {
441                 error = PTR_ERR(inode);
442                 spin_lock(&mq_lock);
443                 ipc_ns->mq_queues_count--;
444                 goto out_unlock;
445         }
446 
447         put_ipc_ns(ipc_ns);
448         dir->i_size += DIRENT_SIZE;
449         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
450 
451         d_instantiate(dentry, inode);
452         dget(dentry);
453         return 0;
454 out_unlock:
455         spin_unlock(&mq_lock);
456         if (ipc_ns)
457                 put_ipc_ns(ipc_ns);
458         return error;
459 }
460 
461 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
462 {
463         struct inode *inode = d_inode(dentry);
464 
465         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
466         dir->i_size -= DIRENT_SIZE;
467         drop_nlink(inode);
468         dput(dentry);
469         return 0;
470 }
471 
472 /*
473 *       This is routine for system read from queue file.
474 *       To avoid mess with doing here some sort of mq_receive we allow
475 *       to read only queue size & notification info (the only values
476 *       that are interesting from user point of view and aren't accessible
477 *       through std routines)
478 */
479 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
480                                 size_t count, loff_t *off)
481 {
482         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
483         char buffer[FILENT_SIZE];
484         ssize_t ret;
485 
486         spin_lock(&info->lock);
487         snprintf(buffer, sizeof(buffer),
488                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
489                         info->qsize,
490                         info->notify_owner ? info->notify.sigev_notify : 0,
491                         (info->notify_owner &&
492                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
493                                 info->notify.sigev_signo : 0,
494                         pid_vnr(info->notify_owner));
495         spin_unlock(&info->lock);
496         buffer[sizeof(buffer)-1] = '\0';
497 
498         ret = simple_read_from_buffer(u_data, count, off, buffer,
499                                 strlen(buffer));
500         if (ret <= 0)
501                 return ret;
502 
503         file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME;
504         return ret;
505 }
506 
507 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
508 {
509         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
510 
511         spin_lock(&info->lock);
512         if (task_tgid(current) == info->notify_owner)
513                 remove_notification(info);
514 
515         spin_unlock(&info->lock);
516         return 0;
517 }
518 
519 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
520 {
521         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
522         int retval = 0;
523 
524         poll_wait(filp, &info->wait_q, poll_tab);
525 
526         spin_lock(&info->lock);
527         if (info->attr.mq_curmsgs)
528                 retval = POLLIN | POLLRDNORM;
529 
530         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
531                 retval |= POLLOUT | POLLWRNORM;
532         spin_unlock(&info->lock);
533 
534         return retval;
535 }
536 
537 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
538 static void wq_add(struct mqueue_inode_info *info, int sr,
539                         struct ext_wait_queue *ewp)
540 {
541         struct ext_wait_queue *walk;
542 
543         ewp->task = current;
544 
545         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
546                 if (walk->task->static_prio <= current->static_prio) {
547                         list_add_tail(&ewp->list, &walk->list);
548                         return;
549                 }
550         }
551         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
552 }
553 
554 /*
555  * Puts current task to sleep. Caller must hold queue lock. After return
556  * lock isn't held.
557  * sr: SEND or RECV
558  */
559 static int wq_sleep(struct mqueue_inode_info *info, int sr,
560                     ktime_t *timeout, struct ext_wait_queue *ewp)
561 {
562         int retval;
563         signed long time;
564 
565         wq_add(info, sr, ewp);
566 
567         for (;;) {
568                 __set_current_state(TASK_INTERRUPTIBLE);
569 
570                 spin_unlock(&info->lock);
571                 time = schedule_hrtimeout_range_clock(timeout, 0,
572                         HRTIMER_MODE_ABS, CLOCK_REALTIME);
573 
574                 if (ewp->state == STATE_READY) {
575                         retval = 0;
576                         goto out;
577                 }
578                 spin_lock(&info->lock);
579                 if (ewp->state == STATE_READY) {
580                         retval = 0;
581                         goto out_unlock;
582                 }
583                 if (signal_pending(current)) {
584                         retval = -ERESTARTSYS;
585                         break;
586                 }
587                 if (time == 0) {
588                         retval = -ETIMEDOUT;
589                         break;
590                 }
591         }
592         list_del(&ewp->list);
593 out_unlock:
594         spin_unlock(&info->lock);
595 out:
596         return retval;
597 }
598 
599 /*
600  * Returns waiting task that should be serviced first or NULL if none exists
601  */
602 static struct ext_wait_queue *wq_get_first_waiter(
603                 struct mqueue_inode_info *info, int sr)
604 {
605         struct list_head *ptr;
606 
607         ptr = info->e_wait_q[sr].list.prev;
608         if (ptr == &info->e_wait_q[sr].list)
609                 return NULL;
610         return list_entry(ptr, struct ext_wait_queue, list);
611 }
612 
613 
614 static inline void set_cookie(struct sk_buff *skb, char code)
615 {
616         ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
617 }
618 
619 /*
620  * The next function is only to split too long sys_mq_timedsend
621  */
622 static void __do_notify(struct mqueue_inode_info *info)
623 {
624         /* notification
625          * invoked when there is registered process and there isn't process
626          * waiting synchronously for message AND state of queue changed from
627          * empty to not empty. Here we are sure that no one is waiting
628          * synchronously. */
629         if (info->notify_owner &&
630             info->attr.mq_curmsgs == 1) {
631                 struct siginfo sig_i;
632                 switch (info->notify.sigev_notify) {
633                 case SIGEV_NONE:
634                         break;
635                 case SIGEV_SIGNAL:
636                         /* sends signal */
637 
638                         sig_i.si_signo = info->notify.sigev_signo;
639                         sig_i.si_errno = 0;
640                         sig_i.si_code = SI_MESGQ;
641                         sig_i.si_value = info->notify.sigev_value;
642                         /* map current pid/uid into info->owner's namespaces */
643                         rcu_read_lock();
644                         sig_i.si_pid = task_tgid_nr_ns(current,
645                                                 ns_of_pid(info->notify_owner));
646                         sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
647                         rcu_read_unlock();
648 
649                         kill_pid_info(info->notify.sigev_signo,
650                                       &sig_i, info->notify_owner);
651                         break;
652                 case SIGEV_THREAD:
653                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
654                         netlink_sendskb(info->notify_sock, info->notify_cookie);
655                         break;
656                 }
657                 /* after notification unregisters process */
658                 put_pid(info->notify_owner);
659                 put_user_ns(info->notify_user_ns);
660                 info->notify_owner = NULL;
661                 info->notify_user_ns = NULL;
662         }
663         wake_up(&info->wait_q);
664 }
665 
666 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
667                            ktime_t *expires, struct timespec *ts)
668 {
669         if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
670                 return -EFAULT;
671         if (!timespec_valid(ts))
672                 return -EINVAL;
673 
674         *expires = timespec_to_ktime(*ts);
675         return 0;
676 }
677 
678 static void remove_notification(struct mqueue_inode_info *info)
679 {
680         if (info->notify_owner != NULL &&
681             info->notify.sigev_notify == SIGEV_THREAD) {
682                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
683                 netlink_sendskb(info->notify_sock, info->notify_cookie);
684         }
685         put_pid(info->notify_owner);
686         put_user_ns(info->notify_user_ns);
687         info->notify_owner = NULL;
688         info->notify_user_ns = NULL;
689 }
690 
691 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
692 {
693         int mq_treesize;
694         unsigned long total_size;
695 
696         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
697                 return -EINVAL;
698         if (capable(CAP_SYS_RESOURCE)) {
699                 if (attr->mq_maxmsg > HARD_MSGMAX ||
700                     attr->mq_msgsize > HARD_MSGSIZEMAX)
701                         return -EINVAL;
702         } else {
703                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
704                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
705                         return -EINVAL;
706         }
707         /* check for overflow */
708         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
709                 return -EOVERFLOW;
710         mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
711                 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
712                 sizeof(struct posix_msg_tree_node);
713         total_size = attr->mq_maxmsg * attr->mq_msgsize;
714         if (total_size + mq_treesize < total_size)
715                 return -EOVERFLOW;
716         return 0;
717 }
718 
719 /*
720  * Invoked when creating a new queue via sys_mq_open
721  */
722 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
723                         struct path *path, int oflag, umode_t mode,
724                         struct mq_attr *attr)
725 {
726         const struct cred *cred = current_cred();
727         int ret;
728 
729         if (attr) {
730                 ret = mq_attr_ok(ipc_ns, attr);
731                 if (ret)
732                         return ERR_PTR(ret);
733                 /* store for use during create */
734                 path->dentry->d_fsdata = attr;
735         } else {
736                 struct mq_attr def_attr;
737 
738                 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
739                                          ipc_ns->mq_msg_default);
740                 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
741                                           ipc_ns->mq_msgsize_default);
742                 ret = mq_attr_ok(ipc_ns, &def_attr);
743                 if (ret)
744                         return ERR_PTR(ret);
745         }
746 
747         mode &= ~current_umask();
748         ret = vfs_create(dir, path->dentry, mode, true);
749         path->dentry->d_fsdata = NULL;
750         if (ret)
751                 return ERR_PTR(ret);
752         return dentry_open(path, oflag, cred);
753 }
754 
755 /* Opens existing queue */
756 static struct file *do_open(struct path *path, int oflag)
757 {
758         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
759                                                   MAY_READ | MAY_WRITE };
760         int acc;
761         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
762                 return ERR_PTR(-EINVAL);
763         acc = oflag2acc[oflag & O_ACCMODE];
764         if (inode_permission(d_inode(path->dentry), acc))
765                 return ERR_PTR(-EACCES);
766         return dentry_open(path, oflag, current_cred());
767 }
768 
769 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
770                 struct mq_attr __user *, u_attr)
771 {
772         struct path path;
773         struct file *filp;
774         struct filename *name;
775         struct mq_attr attr;
776         int fd, error;
777         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
778         struct vfsmount *mnt = ipc_ns->mq_mnt;
779         struct dentry *root = mnt->mnt_root;
780         int ro;
781 
782         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
783                 return -EFAULT;
784 
785         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
786 
787         if (IS_ERR(name = getname(u_name)))
788                 return PTR_ERR(name);
789 
790         fd = get_unused_fd_flags(O_CLOEXEC);
791         if (fd < 0)
792                 goto out_putname;
793 
794         ro = mnt_want_write(mnt);       /* we'll drop it in any case */
795         error = 0;
796         inode_lock(d_inode(root));
797         path.dentry = lookup_one_len(name->name, root, strlen(name->name));
798         if (IS_ERR(path.dentry)) {
799                 error = PTR_ERR(path.dentry);
800                 goto out_putfd;
801         }
802         path.mnt = mntget(mnt);
803 
804         if (oflag & O_CREAT) {
805                 if (d_really_is_positive(path.dentry)) {        /* entry already exists */
806                         audit_inode(name, path.dentry, 0);
807                         if (oflag & O_EXCL) {
808                                 error = -EEXIST;
809                                 goto out;
810                         }
811                         filp = do_open(&path, oflag);
812                 } else {
813                         if (ro) {
814                                 error = ro;
815                                 goto out;
816                         }
817                         audit_inode_parent_hidden(name, root);
818                         filp = do_create(ipc_ns, d_inode(root),
819                                                 &path, oflag, mode,
820                                                 u_attr ? &attr : NULL);
821                 }
822         } else {
823                 if (d_really_is_negative(path.dentry)) {
824                         error = -ENOENT;
825                         goto out;
826                 }
827                 audit_inode(name, path.dentry, 0);
828                 filp = do_open(&path, oflag);
829         }
830 
831         if (!IS_ERR(filp))
832                 fd_install(fd, filp);
833         else
834                 error = PTR_ERR(filp);
835 out:
836         path_put(&path);
837 out_putfd:
838         if (error) {
839                 put_unused_fd(fd);
840                 fd = error;
841         }
842         inode_unlock(d_inode(root));
843         if (!ro)
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         struct filename *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         audit_inode_parent_hidden(name, mnt->mnt_root);
864         err = mnt_want_write(mnt);
865         if (err)
866                 goto out_name;
867         inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
868         dentry = lookup_one_len(name->name, mnt->mnt_root,
869                                 strlen(name->name));
870         if (IS_ERR(dentry)) {
871                 err = PTR_ERR(dentry);
872                 goto out_unlock;
873         }
874 
875         inode = d_inode(dentry);
876         if (!inode) {
877                 err = -ENOENT;
878         } else {
879                 ihold(inode);
880                 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
881         }
882         dput(dentry);
883 
884 out_unlock:
885         inode_unlock(d_inode(mnt->mnt_root));
886         if (inode)
887                 iput(inode);
888         mnt_drop_write(mnt);
889 out_name:
890         putname(name);
891 
892         return err;
893 }
894 
895 /* Pipelined send and receive functions.
896  *
897  * If a receiver finds no waiting message, then it registers itself in the
898  * list of waiting receivers. A sender checks that list before adding the new
899  * message into the message array. If there is a waiting receiver, then it
900  * bypasses the message array and directly hands the message over to the
901  * receiver. The receiver accepts the message and returns without grabbing the
902  * queue spinlock:
903  *
904  * - Set pointer to message.
905  * - Queue the receiver task for later wakeup (without the info->lock).
906  * - Update its state to STATE_READY. Now the receiver can continue.
907  * - Wake up the process after the lock is dropped. Should the process wake up
908  *   before this wakeup (due to a timeout or a signal) it will either see
909  *   STATE_READY and continue or acquire the lock to check the state again.
910  *
911  * The same algorithm is used for senders.
912  */
913 
914 /* pipelined_send() - send a message directly to the task waiting in
915  * sys_mq_timedreceive() (without inserting message into a queue).
916  */
917 static inline void pipelined_send(struct wake_q_head *wake_q,
918                                   struct mqueue_inode_info *info,
919                                   struct msg_msg *message,
920                                   struct ext_wait_queue *receiver)
921 {
922         receiver->msg = message;
923         list_del(&receiver->list);
924         wake_q_add(wake_q, receiver->task);
925         /*
926          * Rely on the implicit cmpxchg barrier from wake_q_add such
927          * that we can ensure that updating receiver->state is the last
928          * write operation: As once set, the receiver can continue,
929          * and if we don't have the reference count from the wake_q,
930          * yet, at that point we can later have a use-after-free
931          * condition and bogus wakeup.
932          */
933         receiver->state = STATE_READY;
934 }
935 
936 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
937  * gets its message and put to the queue (we have one free place for sure). */
938 static inline void pipelined_receive(struct wake_q_head *wake_q,
939                                      struct mqueue_inode_info *info)
940 {
941         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
942 
943         if (!sender) {
944                 /* for poll */
945                 wake_up_interruptible(&info->wait_q);
946                 return;
947         }
948         if (msg_insert(sender->msg, info))
949                 return;
950 
951         list_del(&sender->list);
952         wake_q_add(wake_q, sender->task);
953         sender->state = STATE_READY;
954 }
955 
956 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
957                 size_t, msg_len, unsigned int, msg_prio,
958                 const struct timespec __user *, u_abs_timeout)
959 {
960         struct fd f;
961         struct inode *inode;
962         struct ext_wait_queue wait;
963         struct ext_wait_queue *receiver;
964         struct msg_msg *msg_ptr;
965         struct mqueue_inode_info *info;
966         ktime_t expires, *timeout = NULL;
967         struct timespec ts;
968         struct posix_msg_tree_node *new_leaf = NULL;
969         int ret = 0;
970         WAKE_Q(wake_q);
971 
972         if (u_abs_timeout) {
973                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
974                 if (res)
975                         return res;
976                 timeout = &expires;
977         }
978 
979         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
980                 return -EINVAL;
981 
982         audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
983 
984         f = fdget(mqdes);
985         if (unlikely(!f.file)) {
986                 ret = -EBADF;
987                 goto out;
988         }
989 
990         inode = file_inode(f.file);
991         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
992                 ret = -EBADF;
993                 goto out_fput;
994         }
995         info = MQUEUE_I(inode);
996         audit_file(f.file);
997 
998         if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
999                 ret = -EBADF;
1000                 goto out_fput;
1001         }
1002 
1003         if (unlikely(msg_len > info->attr.mq_msgsize)) {
1004                 ret = -EMSGSIZE;
1005                 goto out_fput;
1006         }
1007 
1008         /* First try to allocate memory, before doing anything with
1009          * existing queues. */
1010         msg_ptr = load_msg(u_msg_ptr, msg_len);
1011         if (IS_ERR(msg_ptr)) {
1012                 ret = PTR_ERR(msg_ptr);
1013                 goto out_fput;
1014         }
1015         msg_ptr->m_ts = msg_len;
1016         msg_ptr->m_type = msg_prio;
1017 
1018         /*
1019          * msg_insert really wants us to have a valid, spare node struct so
1020          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1021          * fall back to that if necessary.
1022          */
1023         if (!info->node_cache)
1024                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1025 
1026         spin_lock(&info->lock);
1027 
1028         if (!info->node_cache && new_leaf) {
1029                 /* Save our speculative allocation into the cache */
1030                 INIT_LIST_HEAD(&new_leaf->msg_list);
1031                 info->node_cache = new_leaf;
1032                 new_leaf = NULL;
1033         } else {
1034                 kfree(new_leaf);
1035         }
1036 
1037         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1038                 if (f.file->f_flags & O_NONBLOCK) {
1039                         ret = -EAGAIN;
1040                 } else {
1041                         wait.task = current;
1042                         wait.msg = (void *) msg_ptr;
1043                         wait.state = STATE_NONE;
1044                         ret = wq_sleep(info, SEND, timeout, &wait);
1045                         /*
1046                          * wq_sleep must be called with info->lock held, and
1047                          * returns with the lock released
1048                          */
1049                         goto out_free;
1050                 }
1051         } else {
1052                 receiver = wq_get_first_waiter(info, RECV);
1053                 if (receiver) {
1054                         pipelined_send(&wake_q, info, msg_ptr, receiver);
1055                 } else {
1056                         /* adds message to the queue */
1057                         ret = msg_insert(msg_ptr, info);
1058                         if (ret)
1059                                 goto out_unlock;
1060                         __do_notify(info);
1061                 }
1062                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1063                                 CURRENT_TIME;
1064         }
1065 out_unlock:
1066         spin_unlock(&info->lock);
1067         wake_up_q(&wake_q);
1068 out_free:
1069         if (ret)
1070                 free_msg(msg_ptr);
1071 out_fput:
1072         fdput(f);
1073 out:
1074         return ret;
1075 }
1076 
1077 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1078                 size_t, msg_len, unsigned int __user *, u_msg_prio,
1079                 const struct timespec __user *, u_abs_timeout)
1080 {
1081         ssize_t ret;
1082         struct msg_msg *msg_ptr;
1083         struct fd f;
1084         struct inode *inode;
1085         struct mqueue_inode_info *info;
1086         struct ext_wait_queue wait;
1087         ktime_t expires, *timeout = NULL;
1088         struct timespec ts;
1089         struct posix_msg_tree_node *new_leaf = NULL;
1090 
1091         if (u_abs_timeout) {
1092                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1093                 if (res)
1094                         return res;
1095                 timeout = &expires;
1096         }
1097 
1098         audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1099 
1100         f = fdget(mqdes);
1101         if (unlikely(!f.file)) {
1102                 ret = -EBADF;
1103                 goto out;
1104         }
1105 
1106         inode = file_inode(f.file);
1107         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1108                 ret = -EBADF;
1109                 goto out_fput;
1110         }
1111         info = MQUEUE_I(inode);
1112         audit_file(f.file);
1113 
1114         if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1115                 ret = -EBADF;
1116                 goto out_fput;
1117         }
1118 
1119         /* checks if buffer is big enough */
1120         if (unlikely(msg_len < info->attr.mq_msgsize)) {
1121                 ret = -EMSGSIZE;
1122                 goto out_fput;
1123         }
1124 
1125         /*
1126          * msg_insert really wants us to have a valid, spare node struct so
1127          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1128          * fall back to that if necessary.
1129          */
1130         if (!info->node_cache)
1131                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1132 
1133         spin_lock(&info->lock);
1134 
1135         if (!info->node_cache && new_leaf) {
1136                 /* Save our speculative allocation into the cache */
1137                 INIT_LIST_HEAD(&new_leaf->msg_list);
1138                 info->node_cache = new_leaf;
1139         } else {
1140                 kfree(new_leaf);
1141         }
1142 
1143         if (info->attr.mq_curmsgs == 0) {
1144                 if (f.file->f_flags & O_NONBLOCK) {
1145                         spin_unlock(&info->lock);
1146                         ret = -EAGAIN;
1147                 } else {
1148                         wait.task = current;
1149                         wait.state = STATE_NONE;
1150                         ret = wq_sleep(info, RECV, timeout, &wait);
1151                         msg_ptr = wait.msg;
1152                 }
1153         } else {
1154                 WAKE_Q(wake_q);
1155 
1156                 msg_ptr = msg_get(info);
1157 
1158                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1159                                 CURRENT_TIME;
1160 
1161                 /* There is now free space in queue. */
1162                 pipelined_receive(&wake_q, info);
1163                 spin_unlock(&info->lock);
1164                 wake_up_q(&wake_q);
1165                 ret = 0;
1166         }
1167         if (ret == 0) {
1168                 ret = msg_ptr->m_ts;
1169 
1170                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1171                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1172                         ret = -EFAULT;
1173                 }
1174                 free_msg(msg_ptr);
1175         }
1176 out_fput:
1177         fdput(f);
1178 out:
1179         return ret;
1180 }
1181 
1182 /*
1183  * Notes: the case when user wants us to deregister (with NULL as pointer)
1184  * and he isn't currently owner of notification, will be silently discarded.
1185  * It isn't explicitly defined in the POSIX.
1186  */
1187 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1188                 const struct sigevent __user *, u_notification)
1189 {
1190         int ret;
1191         struct fd f;
1192         struct sock *sock;
1193         struct inode *inode;
1194         struct sigevent notification;
1195         struct mqueue_inode_info *info;
1196         struct sk_buff *nc;
1197 
1198         if (u_notification) {
1199                 if (copy_from_user(&notification, u_notification,
1200                                         sizeof(struct sigevent)))
1201                         return -EFAULT;
1202         }
1203 
1204         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1205 
1206         nc = NULL;
1207         sock = NULL;
1208         if (u_notification != NULL) {
1209                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1210                              notification.sigev_notify != SIGEV_SIGNAL &&
1211                              notification.sigev_notify != SIGEV_THREAD))
1212                         return -EINVAL;
1213                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1214                         !valid_signal(notification.sigev_signo)) {
1215                         return -EINVAL;
1216                 }
1217                 if (notification.sigev_notify == SIGEV_THREAD) {
1218                         long timeo;
1219 
1220                         /* create the notify skb */
1221                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1222                         if (!nc) {
1223                                 ret = -ENOMEM;
1224                                 goto out;
1225                         }
1226                         if (copy_from_user(nc->data,
1227                                         notification.sigev_value.sival_ptr,
1228                                         NOTIFY_COOKIE_LEN)) {
1229                                 ret = -EFAULT;
1230                                 goto out;
1231                         }
1232 
1233                         /* TODO: add a header? */
1234                         skb_put(nc, NOTIFY_COOKIE_LEN);
1235                         /* and attach it to the socket */
1236 retry:
1237                         f = fdget(notification.sigev_signo);
1238                         if (!f.file) {
1239                                 ret = -EBADF;
1240                                 goto out;
1241                         }
1242                         sock = netlink_getsockbyfilp(f.file);
1243                         fdput(f);
1244                         if (IS_ERR(sock)) {
1245                                 ret = PTR_ERR(sock);
1246                                 sock = NULL;
1247                                 goto out;
1248                         }
1249 
1250                         timeo = MAX_SCHEDULE_TIMEOUT;
1251                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1252                         if (ret == 1)
1253                                 goto retry;
1254                         if (ret) {
1255                                 sock = NULL;
1256                                 nc = NULL;
1257                                 goto out;
1258                         }
1259                 }
1260         }
1261 
1262         f = fdget(mqdes);
1263         if (!f.file) {
1264                 ret = -EBADF;
1265                 goto out;
1266         }
1267 
1268         inode = file_inode(f.file);
1269         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1270                 ret = -EBADF;
1271                 goto out_fput;
1272         }
1273         info = MQUEUE_I(inode);
1274 
1275         ret = 0;
1276         spin_lock(&info->lock);
1277         if (u_notification == NULL) {
1278                 if (info->notify_owner == task_tgid(current)) {
1279                         remove_notification(info);
1280                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1281                 }
1282         } else if (info->notify_owner != NULL) {
1283                 ret = -EBUSY;
1284         } else {
1285                 switch (notification.sigev_notify) {
1286                 case SIGEV_NONE:
1287                         info->notify.sigev_notify = SIGEV_NONE;
1288                         break;
1289                 case SIGEV_THREAD:
1290                         info->notify_sock = sock;
1291                         info->notify_cookie = nc;
1292                         sock = NULL;
1293                         nc = NULL;
1294                         info->notify.sigev_notify = SIGEV_THREAD;
1295                         break;
1296                 case SIGEV_SIGNAL:
1297                         info->notify.sigev_signo = notification.sigev_signo;
1298                         info->notify.sigev_value = notification.sigev_value;
1299                         info->notify.sigev_notify = SIGEV_SIGNAL;
1300                         break;
1301                 }
1302 
1303                 info->notify_owner = get_pid(task_tgid(current));
1304                 info->notify_user_ns = get_user_ns(current_user_ns());
1305                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1306         }
1307         spin_unlock(&info->lock);
1308 out_fput:
1309         fdput(f);
1310 out:
1311         if (sock)
1312                 netlink_detachskb(sock, nc);
1313         else if (nc)
1314                 dev_kfree_skb(nc);
1315 
1316         return ret;
1317 }
1318 
1319 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1320                 const struct mq_attr __user *, u_mqstat,
1321                 struct mq_attr __user *, u_omqstat)
1322 {
1323         int ret;
1324         struct mq_attr mqstat, omqstat;
1325         struct fd f;
1326         struct inode *inode;
1327         struct mqueue_inode_info *info;
1328 
1329         if (u_mqstat != NULL) {
1330                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1331                         return -EFAULT;
1332                 if (mqstat.mq_flags & (~O_NONBLOCK))
1333                         return -EINVAL;
1334         }
1335 
1336         f = fdget(mqdes);
1337         if (!f.file) {
1338                 ret = -EBADF;
1339                 goto out;
1340         }
1341 
1342         inode = file_inode(f.file);
1343         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1344                 ret = -EBADF;
1345                 goto out_fput;
1346         }
1347         info = MQUEUE_I(inode);
1348 
1349         spin_lock(&info->lock);
1350 
1351         omqstat = info->attr;
1352         omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1353         if (u_mqstat) {
1354                 audit_mq_getsetattr(mqdes, &mqstat);
1355                 spin_lock(&f.file->f_lock);
1356                 if (mqstat.mq_flags & O_NONBLOCK)
1357                         f.file->f_flags |= O_NONBLOCK;
1358                 else
1359                         f.file->f_flags &= ~O_NONBLOCK;
1360                 spin_unlock(&f.file->f_lock);
1361 
1362                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1363         }
1364 
1365         spin_unlock(&info->lock);
1366 
1367         ret = 0;
1368         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1369                                                 sizeof(struct mq_attr)))
1370                 ret = -EFAULT;
1371 
1372 out_fput:
1373         fdput(f);
1374 out:
1375         return ret;
1376 }
1377 
1378 static const struct inode_operations mqueue_dir_inode_operations = {
1379         .lookup = simple_lookup,
1380         .create = mqueue_create,
1381         .unlink = mqueue_unlink,
1382 };
1383 
1384 static const struct file_operations mqueue_file_operations = {
1385         .flush = mqueue_flush_file,
1386         .poll = mqueue_poll_file,
1387         .read = mqueue_read_file,
1388         .llseek = default_llseek,
1389 };
1390 
1391 static const struct super_operations mqueue_super_ops = {
1392         .alloc_inode = mqueue_alloc_inode,
1393         .destroy_inode = mqueue_destroy_inode,
1394         .evict_inode = mqueue_evict_inode,
1395         .statfs = simple_statfs,
1396 };
1397 
1398 static struct file_system_type mqueue_fs_type = {
1399         .name = "mqueue",
1400         .mount = mqueue_mount,
1401         .kill_sb = kill_litter_super,
1402         .fs_flags = FS_USERNS_MOUNT,
1403 };
1404 
1405 int mq_init_ns(struct ipc_namespace *ns)
1406 {
1407         ns->mq_queues_count  = 0;
1408         ns->mq_queues_max    = DFLT_QUEUESMAX;
1409         ns->mq_msg_max       = DFLT_MSGMAX;
1410         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1411         ns->mq_msg_default   = DFLT_MSG;
1412         ns->mq_msgsize_default  = DFLT_MSGSIZE;
1413 
1414         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1415         if (IS_ERR(ns->mq_mnt)) {
1416                 int err = PTR_ERR(ns->mq_mnt);
1417                 ns->mq_mnt = NULL;
1418                 return err;
1419         }
1420         return 0;
1421 }
1422 
1423 void mq_clear_sbinfo(struct ipc_namespace *ns)
1424 {
1425         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1426 }
1427 
1428 void mq_put_mnt(struct ipc_namespace *ns)
1429 {
1430         kern_unmount(ns->mq_mnt);
1431 }
1432 
1433 static int __init init_mqueue_fs(void)
1434 {
1435         int error;
1436 
1437         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1438                                 sizeof(struct mqueue_inode_info), 0,
1439                                 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1440         if (mqueue_inode_cachep == NULL)
1441                 return -ENOMEM;
1442 
1443         /* ignore failures - they are not fatal */
1444         mq_sysctl_table = mq_register_sysctl_table();
1445 
1446         error = register_filesystem(&mqueue_fs_type);
1447         if (error)
1448                 goto out_sysctl;
1449 
1450         spin_lock_init(&mq_lock);
1451 
1452         error = mq_init_ns(&init_ipc_ns);
1453         if (error)
1454                 goto out_filesystem;
1455 
1456         return 0;
1457 
1458 out_filesystem:
1459         unregister_filesystem(&mqueue_fs_type);
1460 out_sysctl:
1461         if (mq_sysctl_table)
1462                 unregister_sysctl_table(mq_sysctl_table);
1463         kmem_cache_destroy(mqueue_inode_cachep);
1464         return error;
1465 }
1466 
1467 device_initcall(init_mqueue_fs);
1468 

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