Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

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_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                 info->qsize += sizeof(*leaf);
147         }
148         leaf->priority = msg->m_type;
149         rb_link_node(&leaf->rb_node, parent, p);
150         rb_insert_color(&leaf->rb_node, &info->msg_tree);
151 insert_msg:
152         info->attr.mq_curmsgs++;
153         info->qsize += msg->m_ts;
154         list_add_tail(&msg->m_list, &leaf->msg_list);
155         return 0;
156 }
157 
158 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
159 {
160         struct rb_node **p, *parent = NULL;
161         struct posix_msg_tree_node *leaf;
162         struct msg_msg *msg;
163 
164 try_again:
165         p = &info->msg_tree.rb_node;
166         while (*p) {
167                 parent = *p;
168                 /*
169                  * During insert, low priorities go to the left and high to the
170                  * right.  On receive, we want the highest priorities first, so
171                  * walk all the way to the right.
172                  */
173                 p = &(*p)->rb_right;
174         }
175         if (!parent) {
176                 if (info->attr.mq_curmsgs) {
177                         pr_warn_once("Inconsistency in POSIX message queue, "
178                                      "no tree element, but supposedly messages "
179                                      "should exist!\n");
180                         info->attr.mq_curmsgs = 0;
181                 }
182                 return NULL;
183         }
184         leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
185         if (unlikely(list_empty(&leaf->msg_list))) {
186                 pr_warn_once("Inconsistency in POSIX message queue, "
187                              "empty leaf node but we haven't implemented "
188                              "lazy leaf delete!\n");
189                 rb_erase(&leaf->rb_node, &info->msg_tree);
190                 if (info->node_cache) {
191                         info->qsize -= sizeof(*leaf);
192                         kfree(leaf);
193                 } else {
194                         info->node_cache = leaf;
195                 }
196                 goto try_again;
197         } else {
198                 msg = list_first_entry(&leaf->msg_list,
199                                        struct msg_msg, m_list);
200                 list_del(&msg->m_list);
201                 if (list_empty(&leaf->msg_list)) {
202                         rb_erase(&leaf->rb_node, &info->msg_tree);
203                         if (info->node_cache) {
204                                 info->qsize -= sizeof(*leaf);
205                                 kfree(leaf);
206                         } else {
207                                 info->node_cache = leaf;
208                         }
209                 }
210         }
211         info->attr.mq_curmsgs--;
212         info->qsize -= msg->m_ts;
213         return msg;
214 }
215 
216 static struct inode *mqueue_get_inode(struct super_block *sb,
217                 struct ipc_namespace *ipc_ns, umode_t mode,
218                 struct mq_attr *attr)
219 {
220         struct user_struct *u = current_user();
221         struct inode *inode;
222         int ret = -ENOMEM;
223 
224         inode = new_inode(sb);
225         if (!inode)
226                 goto err;
227 
228         inode->i_ino = get_next_ino();
229         inode->i_mode = mode;
230         inode->i_uid = current_fsuid();
231         inode->i_gid = current_fsgid();
232         inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
233 
234         if (S_ISREG(mode)) {
235                 struct mqueue_inode_info *info;
236                 unsigned long mq_bytes, mq_treesize;
237 
238                 inode->i_fop = &mqueue_file_operations;
239                 inode->i_size = FILENT_SIZE;
240                 /* mqueue specific info */
241                 info = MQUEUE_I(inode);
242                 spin_lock_init(&info->lock);
243                 init_waitqueue_head(&info->wait_q);
244                 INIT_LIST_HEAD(&info->e_wait_q[0].list);
245                 INIT_LIST_HEAD(&info->e_wait_q[1].list);
246                 info->notify_owner = NULL;
247                 info->notify_user_ns = NULL;
248                 info->qsize = 0;
249                 info->user = NULL;      /* set when all is ok */
250                 info->msg_tree = RB_ROOT;
251                 info->node_cache = NULL;
252                 memset(&info->attr, 0, sizeof(info->attr));
253                 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
254                                            ipc_ns->mq_msg_default);
255                 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
256                                             ipc_ns->mq_msgsize_default);
257                 if (attr) {
258                         info->attr.mq_maxmsg = attr->mq_maxmsg;
259                         info->attr.mq_msgsize = attr->mq_msgsize;
260                 }
261                 /*
262                  * We used to allocate a static array of pointers and account
263                  * the size of that array as well as one msg_msg struct per
264                  * possible message into the queue size. That's no longer
265                  * accurate as the queue is now an rbtree and will grow and
266                  * shrink depending on usage patterns.  We can, however, still
267                  * account one msg_msg struct per message, but the nodes are
268                  * allocated depending on priority usage, and most programs
269                  * only use one, or a handful, of priorities.  However, since
270                  * this is pinned memory, we need to assume worst case, so
271                  * that means the min(mq_maxmsg, max_priorities) * struct
272                  * posix_msg_tree_node.
273                  */
274                 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
275                         min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
276                         sizeof(struct posix_msg_tree_node);
277 
278                 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
279                                           info->attr.mq_msgsize);
280 
281                 spin_lock(&mq_lock);
282                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
283                     u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
284                         spin_unlock(&mq_lock);
285                         /* mqueue_evict_inode() releases info->messages */
286                         ret = -EMFILE;
287                         goto out_inode;
288                 }
289                 u->mq_bytes += mq_bytes;
290                 spin_unlock(&mq_lock);
291 
292                 /* all is ok */
293                 info->user = get_uid(u);
294         } else if (S_ISDIR(mode)) {
295                 inc_nlink(inode);
296                 /* Some things misbehave if size == 0 on a directory */
297                 inode->i_size = 2 * DIRENT_SIZE;
298                 inode->i_op = &mqueue_dir_inode_operations;
299                 inode->i_fop = &simple_dir_operations;
300         }
301 
302         return inode;
303 out_inode:
304         iput(inode);
305 err:
306         return ERR_PTR(ret);
307 }
308 
309 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
310 {
311         struct inode *inode;
312         struct ipc_namespace *ns = data;
313 
314         sb->s_blocksize = PAGE_CACHE_SIZE;
315         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
316         sb->s_magic = MQUEUE_MAGIC;
317         sb->s_op = &mqueue_super_ops;
318 
319         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
320         if (IS_ERR(inode))
321                 return PTR_ERR(inode);
322 
323         sb->s_root = d_make_root(inode);
324         if (!sb->s_root)
325                 return -ENOMEM;
326         return 0;
327 }
328 
329 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
330                          int flags, const char *dev_name,
331                          void *data)
332 {
333         if (!(flags & MS_KERNMOUNT)) {
334                 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
335                 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
336                  * over the ipc namespace.
337                  */
338                 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
339                         return ERR_PTR(-EPERM);
340 
341                 data = ns;
342         }
343         return mount_ns(fs_type, flags, data, mqueue_fill_super);
344 }
345 
346 static void init_once(void *foo)
347 {
348         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
349 
350         inode_init_once(&p->vfs_inode);
351 }
352 
353 static struct inode *mqueue_alloc_inode(struct super_block *sb)
354 {
355         struct mqueue_inode_info *ei;
356 
357         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
358         if (!ei)
359                 return NULL;
360         return &ei->vfs_inode;
361 }
362 
363 static void mqueue_i_callback(struct rcu_head *head)
364 {
365         struct inode *inode = container_of(head, struct inode, i_rcu);
366         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
367 }
368 
369 static void mqueue_destroy_inode(struct inode *inode)
370 {
371         call_rcu(&inode->i_rcu, mqueue_i_callback);
372 }
373 
374 static void mqueue_evict_inode(struct inode *inode)
375 {
376         struct mqueue_inode_info *info;
377         struct user_struct *user;
378         unsigned long mq_bytes, mq_treesize;
379         struct ipc_namespace *ipc_ns;
380         struct msg_msg *msg;
381 
382         clear_inode(inode);
383 
384         if (S_ISDIR(inode->i_mode))
385                 return;
386 
387         ipc_ns = get_ns_from_inode(inode);
388         info = MQUEUE_I(inode);
389         spin_lock(&info->lock);
390         while ((msg = msg_get(info)) != NULL)
391                 free_msg(msg);
392         kfree(info->node_cache);
393         spin_unlock(&info->lock);
394 
395         /* Total amount of bytes accounted for the mqueue */
396         mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
397                 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
398                 sizeof(struct posix_msg_tree_node);
399 
400         mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
401                                   info->attr.mq_msgsize);
402 
403         user = info->user;
404         if (user) {
405                 spin_lock(&mq_lock);
406                 user->mq_bytes -= mq_bytes;
407                 /*
408                  * get_ns_from_inode() ensures that the
409                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
410                  * to which we now hold a reference, or it is NULL.
411                  * We can't put it here under mq_lock, though.
412                  */
413                 if (ipc_ns)
414                         ipc_ns->mq_queues_count--;
415                 spin_unlock(&mq_lock);
416                 free_uid(user);
417         }
418         if (ipc_ns)
419                 put_ipc_ns(ipc_ns);
420 }
421 
422 static int mqueue_create(struct inode *dir, struct dentry *dentry,
423                                 umode_t mode, bool excl)
424 {
425         struct inode *inode;
426         struct mq_attr *attr = dentry->d_fsdata;
427         int error;
428         struct ipc_namespace *ipc_ns;
429 
430         spin_lock(&mq_lock);
431         ipc_ns = __get_ns_from_inode(dir);
432         if (!ipc_ns) {
433                 error = -EACCES;
434                 goto out_unlock;
435         }
436 
437         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
438             !capable(CAP_SYS_RESOURCE)) {
439                 error = -ENOSPC;
440                 goto out_unlock;
441         }
442         ipc_ns->mq_queues_count++;
443         spin_unlock(&mq_lock);
444 
445         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
446         if (IS_ERR(inode)) {
447                 error = PTR_ERR(inode);
448                 spin_lock(&mq_lock);
449                 ipc_ns->mq_queues_count--;
450                 goto out_unlock;
451         }
452 
453         put_ipc_ns(ipc_ns);
454         dir->i_size += DIRENT_SIZE;
455         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
456 
457         d_instantiate(dentry, inode);
458         dget(dentry);
459         return 0;
460 out_unlock:
461         spin_unlock(&mq_lock);
462         if (ipc_ns)
463                 put_ipc_ns(ipc_ns);
464         return error;
465 }
466 
467 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
468 {
469         struct inode *inode = dentry->d_inode;
470 
471         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
472         dir->i_size -= DIRENT_SIZE;
473         drop_nlink(inode);
474         dput(dentry);
475         return 0;
476 }
477 
478 /*
479 *       This is routine for system read from queue file.
480 *       To avoid mess with doing here some sort of mq_receive we allow
481 *       to read only queue size & notification info (the only values
482 *       that are interesting from user point of view and aren't accessible
483 *       through std routines)
484 */
485 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
486                                 size_t count, loff_t *off)
487 {
488         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
489         char buffer[FILENT_SIZE];
490         ssize_t ret;
491 
492         spin_lock(&info->lock);
493         snprintf(buffer, sizeof(buffer),
494                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
495                         info->qsize,
496                         info->notify_owner ? info->notify.sigev_notify : 0,
497                         (info->notify_owner &&
498                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
499                                 info->notify.sigev_signo : 0,
500                         pid_vnr(info->notify_owner));
501         spin_unlock(&info->lock);
502         buffer[sizeof(buffer)-1] = '\0';
503 
504         ret = simple_read_from_buffer(u_data, count, off, buffer,
505                                 strlen(buffer));
506         if (ret <= 0)
507                 return ret;
508 
509         file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME;
510         return ret;
511 }
512 
513 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
514 {
515         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
516 
517         spin_lock(&info->lock);
518         if (task_tgid(current) == info->notify_owner)
519                 remove_notification(info);
520 
521         spin_unlock(&info->lock);
522         return 0;
523 }
524 
525 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
526 {
527         struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
528         int retval = 0;
529 
530         poll_wait(filp, &info->wait_q, poll_tab);
531 
532         spin_lock(&info->lock);
533         if (info->attr.mq_curmsgs)
534                 retval = POLLIN | POLLRDNORM;
535 
536         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
537                 retval |= POLLOUT | POLLWRNORM;
538         spin_unlock(&info->lock);
539 
540         return retval;
541 }
542 
543 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
544 static void wq_add(struct mqueue_inode_info *info, int sr,
545                         struct ext_wait_queue *ewp)
546 {
547         struct ext_wait_queue *walk;
548 
549         ewp->task = current;
550 
551         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
552                 if (walk->task->static_prio <= current->static_prio) {
553                         list_add_tail(&ewp->list, &walk->list);
554                         return;
555                 }
556         }
557         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
558 }
559 
560 /*
561  * Puts current task to sleep. Caller must hold queue lock. After return
562  * lock isn't held.
563  * sr: SEND or RECV
564  */
565 static int wq_sleep(struct mqueue_inode_info *info, int sr,
566                     ktime_t *timeout, struct ext_wait_queue *ewp)
567 {
568         int retval;
569         signed long time;
570 
571         wq_add(info, sr, ewp);
572 
573         for (;;) {
574                 set_current_state(TASK_INTERRUPTIBLE);
575 
576                 spin_unlock(&info->lock);
577                 time = schedule_hrtimeout_range_clock(timeout, 0,
578                         HRTIMER_MODE_ABS, CLOCK_REALTIME);
579 
580                 while (ewp->state == STATE_PENDING)
581                         cpu_relax();
582 
583                 if (ewp->state == STATE_READY) {
584                         retval = 0;
585                         goto out;
586                 }
587                 spin_lock(&info->lock);
588                 if (ewp->state == STATE_READY) {
589                         retval = 0;
590                         goto out_unlock;
591                 }
592                 if (signal_pending(current)) {
593                         retval = -ERESTARTSYS;
594                         break;
595                 }
596                 if (time == 0) {
597                         retval = -ETIMEDOUT;
598                         break;
599                 }
600         }
601         list_del(&ewp->list);
602 out_unlock:
603         spin_unlock(&info->lock);
604 out:
605         return retval;
606 }
607 
608 /*
609  * Returns waiting task that should be serviced first or NULL if none exists
610  */
611 static struct ext_wait_queue *wq_get_first_waiter(
612                 struct mqueue_inode_info *info, int sr)
613 {
614         struct list_head *ptr;
615 
616         ptr = info->e_wait_q[sr].list.prev;
617         if (ptr == &info->e_wait_q[sr].list)
618                 return NULL;
619         return list_entry(ptr, struct ext_wait_queue, list);
620 }
621 
622 
623 static inline void set_cookie(struct sk_buff *skb, char code)
624 {
625         ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
626 }
627 
628 /*
629  * The next function is only to split too long sys_mq_timedsend
630  */
631 static void __do_notify(struct mqueue_inode_info *info)
632 {
633         /* notification
634          * invoked when there is registered process and there isn't process
635          * waiting synchronously for message AND state of queue changed from
636          * empty to not empty. Here we are sure that no one is waiting
637          * synchronously. */
638         if (info->notify_owner &&
639             info->attr.mq_curmsgs == 1) {
640                 struct siginfo sig_i;
641                 switch (info->notify.sigev_notify) {
642                 case SIGEV_NONE:
643                         break;
644                 case SIGEV_SIGNAL:
645                         /* sends signal */
646 
647                         sig_i.si_signo = info->notify.sigev_signo;
648                         sig_i.si_errno = 0;
649                         sig_i.si_code = SI_MESGQ;
650                         sig_i.si_value = info->notify.sigev_value;
651                         /* map current pid/uid into info->owner's namespaces */
652                         rcu_read_lock();
653                         sig_i.si_pid = task_tgid_nr_ns(current,
654                                                 ns_of_pid(info->notify_owner));
655                         sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
656                         rcu_read_unlock();
657 
658                         kill_pid_info(info->notify.sigev_signo,
659                                       &sig_i, info->notify_owner);
660                         break;
661                 case SIGEV_THREAD:
662                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
663                         netlink_sendskb(info->notify_sock, info->notify_cookie);
664                         break;
665                 }
666                 /* after notification unregisters process */
667                 put_pid(info->notify_owner);
668                 put_user_ns(info->notify_user_ns);
669                 info->notify_owner = NULL;
670                 info->notify_user_ns = NULL;
671         }
672         wake_up(&info->wait_q);
673 }
674 
675 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
676                            ktime_t *expires, struct timespec *ts)
677 {
678         if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
679                 return -EFAULT;
680         if (!timespec_valid(ts))
681                 return -EINVAL;
682 
683         *expires = timespec_to_ktime(*ts);
684         return 0;
685 }
686 
687 static void remove_notification(struct mqueue_inode_info *info)
688 {
689         if (info->notify_owner != NULL &&
690             info->notify.sigev_notify == SIGEV_THREAD) {
691                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
692                 netlink_sendskb(info->notify_sock, info->notify_cookie);
693         }
694         put_pid(info->notify_owner);
695         put_user_ns(info->notify_user_ns);
696         info->notify_owner = NULL;
697         info->notify_user_ns = NULL;
698 }
699 
700 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
701 {
702         int mq_treesize;
703         unsigned long total_size;
704 
705         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
706                 return -EINVAL;
707         if (capable(CAP_SYS_RESOURCE)) {
708                 if (attr->mq_maxmsg > HARD_MSGMAX ||
709                     attr->mq_msgsize > HARD_MSGSIZEMAX)
710                         return -EINVAL;
711         } else {
712                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
713                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
714                         return -EINVAL;
715         }
716         /* check for overflow */
717         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
718                 return -EOVERFLOW;
719         mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
720                 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
721                 sizeof(struct posix_msg_tree_node);
722         total_size = attr->mq_maxmsg * attr->mq_msgsize;
723         if (total_size + mq_treesize < total_size)
724                 return -EOVERFLOW;
725         return 0;
726 }
727 
728 /*
729  * Invoked when creating a new queue via sys_mq_open
730  */
731 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
732                         struct path *path, int oflag, umode_t mode,
733                         struct mq_attr *attr)
734 {
735         const struct cred *cred = current_cred();
736         int ret;
737 
738         if (attr) {
739                 ret = mq_attr_ok(ipc_ns, attr);
740                 if (ret)
741                         return ERR_PTR(ret);
742                 /* store for use during create */
743                 path->dentry->d_fsdata = attr;
744         } else {
745                 struct mq_attr def_attr;
746 
747                 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
748                                          ipc_ns->mq_msg_default);
749                 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
750                                           ipc_ns->mq_msgsize_default);
751                 ret = mq_attr_ok(ipc_ns, &def_attr);
752                 if (ret)
753                         return ERR_PTR(ret);
754         }
755 
756         mode &= ~current_umask();
757         ret = vfs_create(dir, path->dentry, mode, true);
758         path->dentry->d_fsdata = NULL;
759         if (ret)
760                 return ERR_PTR(ret);
761         return dentry_open(path, oflag, cred);
762 }
763 
764 /* Opens existing queue */
765 static struct file *do_open(struct path *path, int oflag)
766 {
767         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
768                                                   MAY_READ | MAY_WRITE };
769         int acc;
770         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
771                 return ERR_PTR(-EINVAL);
772         acc = oflag2acc[oflag & O_ACCMODE];
773         if (inode_permission(path->dentry->d_inode, acc))
774                 return ERR_PTR(-EACCES);
775         return dentry_open(path, oflag, current_cred());
776 }
777 
778 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
779                 struct mq_attr __user *, u_attr)
780 {
781         struct path path;
782         struct file *filp;
783         struct filename *name;
784         struct mq_attr attr;
785         int fd, error;
786         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
787         struct vfsmount *mnt = ipc_ns->mq_mnt;
788         struct dentry *root = mnt->mnt_root;
789         int ro;
790 
791         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
792                 return -EFAULT;
793 
794         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
795 
796         if (IS_ERR(name = getname(u_name)))
797                 return PTR_ERR(name);
798 
799         fd = get_unused_fd_flags(O_CLOEXEC);
800         if (fd < 0)
801                 goto out_putname;
802 
803         ro = mnt_want_write(mnt);       /* we'll drop it in any case */
804         error = 0;
805         mutex_lock(&root->d_inode->i_mutex);
806         path.dentry = lookup_one_len(name->name, root, strlen(name->name));
807         if (IS_ERR(path.dentry)) {
808                 error = PTR_ERR(path.dentry);
809                 goto out_putfd;
810         }
811         path.mnt = mntget(mnt);
812 
813         if (oflag & O_CREAT) {
814                 if (path.dentry->d_inode) {     /* entry already exists */
815                         audit_inode(name, path.dentry, 0);
816                         if (oflag & O_EXCL) {
817                                 error = -EEXIST;
818                                 goto out;
819                         }
820                         filp = do_open(&path, oflag);
821                 } else {
822                         if (ro) {
823                                 error = ro;
824                                 goto out;
825                         }
826                         audit_inode_parent_hidden(name, root);
827                         filp = do_create(ipc_ns, root->d_inode,
828                                                 &path, oflag, mode,
829                                                 u_attr ? &attr : NULL);
830                 }
831         } else {
832                 if (!path.dentry->d_inode) {
833                         error = -ENOENT;
834                         goto out;
835                 }
836                 audit_inode(name, path.dentry, 0);
837                 filp = do_open(&path, oflag);
838         }
839 
840         if (!IS_ERR(filp))
841                 fd_install(fd, filp);
842         else
843                 error = PTR_ERR(filp);
844 out:
845         path_put(&path);
846 out_putfd:
847         if (error) {
848                 put_unused_fd(fd);
849                 fd = error;
850         }
851         mutex_unlock(&root->d_inode->i_mutex);
852         if (!ro)
853                 mnt_drop_write(mnt);
854 out_putname:
855         putname(name);
856         return fd;
857 }
858 
859 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
860 {
861         int err;
862         struct filename *name;
863         struct dentry *dentry;
864         struct inode *inode = NULL;
865         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
866         struct vfsmount *mnt = ipc_ns->mq_mnt;
867 
868         name = getname(u_name);
869         if (IS_ERR(name))
870                 return PTR_ERR(name);
871 
872         audit_inode_parent_hidden(name, mnt->mnt_root);
873         err = mnt_want_write(mnt);
874         if (err)
875                 goto out_name;
876         mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT);
877         dentry = lookup_one_len(name->name, mnt->mnt_root,
878                                 strlen(name->name));
879         if (IS_ERR(dentry)) {
880                 err = PTR_ERR(dentry);
881                 goto out_unlock;
882         }
883 
884         inode = dentry->d_inode;
885         if (!inode) {
886                 err = -ENOENT;
887         } else {
888                 ihold(inode);
889                 err = vfs_unlink(dentry->d_parent->d_inode, dentry, NULL);
890         }
891         dput(dentry);
892 
893 out_unlock:
894         mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
895         if (inode)
896                 iput(inode);
897         mnt_drop_write(mnt);
898 out_name:
899         putname(name);
900 
901         return err;
902 }
903 
904 /* Pipelined send and receive functions.
905  *
906  * If a receiver finds no waiting message, then it registers itself in the
907  * list of waiting receivers. A sender checks that list before adding the new
908  * message into the message array. If there is a waiting receiver, then it
909  * bypasses the message array and directly hands the message over to the
910  * receiver.
911  * The receiver accepts the message and returns without grabbing the queue
912  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
913  * are necessary. The same algorithm is used for sysv semaphores, see
914  * ipc/sem.c for more details.
915  *
916  * The same algorithm is used for senders.
917  */
918 
919 /* pipelined_send() - send a message directly to the task waiting in
920  * sys_mq_timedreceive() (without inserting message into a queue).
921  */
922 static inline void pipelined_send(struct mqueue_inode_info *info,
923                                   struct msg_msg *message,
924                                   struct ext_wait_queue *receiver)
925 {
926         receiver->msg = message;
927         list_del(&receiver->list);
928         receiver->state = STATE_PENDING;
929         wake_up_process(receiver->task);
930         smp_wmb();
931         receiver->state = STATE_READY;
932 }
933 
934 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
935  * gets its message and put to the queue (we have one free place for sure). */
936 static inline void pipelined_receive(struct mqueue_inode_info *info)
937 {
938         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
939 
940         if (!sender) {
941                 /* for poll */
942                 wake_up_interruptible(&info->wait_q);
943                 return;
944         }
945         if (msg_insert(sender->msg, info))
946                 return;
947         list_del(&sender->list);
948         sender->state = STATE_PENDING;
949         wake_up_process(sender->task);
950         smp_wmb();
951         sender->state = STATE_READY;
952 }
953 
954 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
955                 size_t, msg_len, unsigned int, msg_prio,
956                 const struct timespec __user *, u_abs_timeout)
957 {
958         struct fd f;
959         struct inode *inode;
960         struct ext_wait_queue wait;
961         struct ext_wait_queue *receiver;
962         struct msg_msg *msg_ptr;
963         struct mqueue_inode_info *info;
964         ktime_t expires, *timeout = NULL;
965         struct timespec ts;
966         struct posix_msg_tree_node *new_leaf = NULL;
967         int ret = 0;
968 
969         if (u_abs_timeout) {
970                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
971                 if (res)
972                         return res;
973                 timeout = &expires;
974         }
975 
976         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
977                 return -EINVAL;
978 
979         audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
980 
981         f = fdget(mqdes);
982         if (unlikely(!f.file)) {
983                 ret = -EBADF;
984                 goto out;
985         }
986 
987         inode = file_inode(f.file);
988         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
989                 ret = -EBADF;
990                 goto out_fput;
991         }
992         info = MQUEUE_I(inode);
993         audit_inode(NULL, f.file->f_path.dentry, 0);
994 
995         if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
996                 ret = -EBADF;
997                 goto out_fput;
998         }
999 
1000         if (unlikely(msg_len > info->attr.mq_msgsize)) {
1001                 ret = -EMSGSIZE;
1002                 goto out_fput;
1003         }
1004 
1005         /* First try to allocate memory, before doing anything with
1006          * existing queues. */
1007         msg_ptr = load_msg(u_msg_ptr, msg_len);
1008         if (IS_ERR(msg_ptr)) {
1009                 ret = PTR_ERR(msg_ptr);
1010                 goto out_fput;
1011         }
1012         msg_ptr->m_ts = msg_len;
1013         msg_ptr->m_type = msg_prio;
1014 
1015         /*
1016          * msg_insert really wants us to have a valid, spare node struct so
1017          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1018          * fall back to that if necessary.
1019          */
1020         if (!info->node_cache)
1021                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1022 
1023         spin_lock(&info->lock);
1024 
1025         if (!info->node_cache && new_leaf) {
1026                 /* Save our speculative allocation into the cache */
1027                 INIT_LIST_HEAD(&new_leaf->msg_list);
1028                 info->node_cache = new_leaf;
1029                 info->qsize += sizeof(*new_leaf);
1030                 new_leaf = NULL;
1031         } else {
1032                 kfree(new_leaf);
1033         }
1034 
1035         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1036                 if (f.file->f_flags & O_NONBLOCK) {
1037                         ret = -EAGAIN;
1038                 } else {
1039                         wait.task = current;
1040                         wait.msg = (void *) msg_ptr;
1041                         wait.state = STATE_NONE;
1042                         ret = wq_sleep(info, SEND, timeout, &wait);
1043                         /*
1044                          * wq_sleep must be called with info->lock held, and
1045                          * returns with the lock released
1046                          */
1047                         goto out_free;
1048                 }
1049         } else {
1050                 receiver = wq_get_first_waiter(info, RECV);
1051                 if (receiver) {
1052                         pipelined_send(info, msg_ptr, receiver);
1053                 } else {
1054                         /* adds message to the queue */
1055                         ret = msg_insert(msg_ptr, info);
1056                         if (ret)
1057                                 goto out_unlock;
1058                         __do_notify(info);
1059                 }
1060                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1061                                 CURRENT_TIME;
1062         }
1063 out_unlock:
1064         spin_unlock(&info->lock);
1065 out_free:
1066         if (ret)
1067                 free_msg(msg_ptr);
1068 out_fput:
1069         fdput(f);
1070 out:
1071         return ret;
1072 }
1073 
1074 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1075                 size_t, msg_len, unsigned int __user *, u_msg_prio,
1076                 const struct timespec __user *, u_abs_timeout)
1077 {
1078         ssize_t ret;
1079         struct msg_msg *msg_ptr;
1080         struct fd f;
1081         struct inode *inode;
1082         struct mqueue_inode_info *info;
1083         struct ext_wait_queue wait;
1084         ktime_t expires, *timeout = NULL;
1085         struct timespec ts;
1086         struct posix_msg_tree_node *new_leaf = NULL;
1087 
1088         if (u_abs_timeout) {
1089                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1090                 if (res)
1091                         return res;
1092                 timeout = &expires;
1093         }
1094 
1095         audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1096 
1097         f = fdget(mqdes);
1098         if (unlikely(!f.file)) {
1099                 ret = -EBADF;
1100                 goto out;
1101         }
1102 
1103         inode = file_inode(f.file);
1104         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1105                 ret = -EBADF;
1106                 goto out_fput;
1107         }
1108         info = MQUEUE_I(inode);
1109         audit_inode(NULL, f.file->f_path.dentry, 0);
1110 
1111         if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1112                 ret = -EBADF;
1113                 goto out_fput;
1114         }
1115 
1116         /* checks if buffer is big enough */
1117         if (unlikely(msg_len < info->attr.mq_msgsize)) {
1118                 ret = -EMSGSIZE;
1119                 goto out_fput;
1120         }
1121 
1122         /*
1123          * msg_insert really wants us to have a valid, spare node struct so
1124          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1125          * fall back to that if necessary.
1126          */
1127         if (!info->node_cache)
1128                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1129 
1130         spin_lock(&info->lock);
1131 
1132         if (!info->node_cache && new_leaf) {
1133                 /* Save our speculative allocation into the cache */
1134                 INIT_LIST_HEAD(&new_leaf->msg_list);
1135                 info->node_cache = new_leaf;
1136                 info->qsize += sizeof(*new_leaf);
1137         } else {
1138                 kfree(new_leaf);
1139         }
1140 
1141         if (info->attr.mq_curmsgs == 0) {
1142                 if (f.file->f_flags & O_NONBLOCK) {
1143                         spin_unlock(&info->lock);
1144                         ret = -EAGAIN;
1145                 } else {
1146                         wait.task = current;
1147                         wait.state = STATE_NONE;
1148                         ret = wq_sleep(info, RECV, timeout, &wait);
1149                         msg_ptr = wait.msg;
1150                 }
1151         } else {
1152                 msg_ptr = msg_get(info);
1153 
1154                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1155                                 CURRENT_TIME;
1156 
1157                 /* There is now free space in queue. */
1158                 pipelined_receive(info);
1159                 spin_unlock(&info->lock);
1160                 ret = 0;
1161         }
1162         if (ret == 0) {
1163                 ret = msg_ptr->m_ts;
1164 
1165                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1166                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1167                         ret = -EFAULT;
1168                 }
1169                 free_msg(msg_ptr);
1170         }
1171 out_fput:
1172         fdput(f);
1173 out:
1174         return ret;
1175 }
1176 
1177 /*
1178  * Notes: the case when user wants us to deregister (with NULL as pointer)
1179  * and he isn't currently owner of notification, will be silently discarded.
1180  * It isn't explicitly defined in the POSIX.
1181  */
1182 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1183                 const struct sigevent __user *, u_notification)
1184 {
1185         int ret;
1186         struct fd f;
1187         struct sock *sock;
1188         struct inode *inode;
1189         struct sigevent notification;
1190         struct mqueue_inode_info *info;
1191         struct sk_buff *nc;
1192 
1193         if (u_notification) {
1194                 if (copy_from_user(&notification, u_notification,
1195                                         sizeof(struct sigevent)))
1196                         return -EFAULT;
1197         }
1198 
1199         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1200 
1201         nc = NULL;
1202         sock = NULL;
1203         if (u_notification != NULL) {
1204                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1205                              notification.sigev_notify != SIGEV_SIGNAL &&
1206                              notification.sigev_notify != SIGEV_THREAD))
1207                         return -EINVAL;
1208                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1209                         !valid_signal(notification.sigev_signo)) {
1210                         return -EINVAL;
1211                 }
1212                 if (notification.sigev_notify == SIGEV_THREAD) {
1213                         long timeo;
1214 
1215                         /* create the notify skb */
1216                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1217                         if (!nc) {
1218                                 ret = -ENOMEM;
1219                                 goto out;
1220                         }
1221                         if (copy_from_user(nc->data,
1222                                         notification.sigev_value.sival_ptr,
1223                                         NOTIFY_COOKIE_LEN)) {
1224                                 ret = -EFAULT;
1225                                 goto out;
1226                         }
1227 
1228                         /* TODO: add a header? */
1229                         skb_put(nc, NOTIFY_COOKIE_LEN);
1230                         /* and attach it to the socket */
1231 retry:
1232                         f = fdget(notification.sigev_signo);
1233                         if (!f.file) {
1234                                 ret = -EBADF;
1235                                 goto out;
1236                         }
1237                         sock = netlink_getsockbyfilp(f.file);
1238                         fdput(f);
1239                         if (IS_ERR(sock)) {
1240                                 ret = PTR_ERR(sock);
1241                                 sock = NULL;
1242                                 goto out;
1243                         }
1244 
1245                         timeo = MAX_SCHEDULE_TIMEOUT;
1246                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1247                         if (ret == 1)
1248                                 goto retry;
1249                         if (ret) {
1250                                 sock = NULL;
1251                                 nc = NULL;
1252                                 goto out;
1253                         }
1254                 }
1255         }
1256 
1257         f = fdget(mqdes);
1258         if (!f.file) {
1259                 ret = -EBADF;
1260                 goto out;
1261         }
1262 
1263         inode = file_inode(f.file);
1264         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1265                 ret = -EBADF;
1266                 goto out_fput;
1267         }
1268         info = MQUEUE_I(inode);
1269 
1270         ret = 0;
1271         spin_lock(&info->lock);
1272         if (u_notification == NULL) {
1273                 if (info->notify_owner == task_tgid(current)) {
1274                         remove_notification(info);
1275                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1276                 }
1277         } else if (info->notify_owner != NULL) {
1278                 ret = -EBUSY;
1279         } else {
1280                 switch (notification.sigev_notify) {
1281                 case SIGEV_NONE:
1282                         info->notify.sigev_notify = SIGEV_NONE;
1283                         break;
1284                 case SIGEV_THREAD:
1285                         info->notify_sock = sock;
1286                         info->notify_cookie = nc;
1287                         sock = NULL;
1288                         nc = NULL;
1289                         info->notify.sigev_notify = SIGEV_THREAD;
1290                         break;
1291                 case SIGEV_SIGNAL:
1292                         info->notify.sigev_signo = notification.sigev_signo;
1293                         info->notify.sigev_value = notification.sigev_value;
1294                         info->notify.sigev_notify = SIGEV_SIGNAL;
1295                         break;
1296                 }
1297 
1298                 info->notify_owner = get_pid(task_tgid(current));
1299                 info->notify_user_ns = get_user_ns(current_user_ns());
1300                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1301         }
1302         spin_unlock(&info->lock);
1303 out_fput:
1304         fdput(f);
1305 out:
1306         if (sock)
1307                 netlink_detachskb(sock, nc);
1308         else if (nc)
1309                 dev_kfree_skb(nc);
1310 
1311         return ret;
1312 }
1313 
1314 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1315                 const struct mq_attr __user *, u_mqstat,
1316                 struct mq_attr __user *, u_omqstat)
1317 {
1318         int ret;
1319         struct mq_attr mqstat, omqstat;
1320         struct fd f;
1321         struct inode *inode;
1322         struct mqueue_inode_info *info;
1323 
1324         if (u_mqstat != NULL) {
1325                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1326                         return -EFAULT;
1327                 if (mqstat.mq_flags & (~O_NONBLOCK))
1328                         return -EINVAL;
1329         }
1330 
1331         f = fdget(mqdes);
1332         if (!f.file) {
1333                 ret = -EBADF;
1334                 goto out;
1335         }
1336 
1337         inode = file_inode(f.file);
1338         if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1339                 ret = -EBADF;
1340                 goto out_fput;
1341         }
1342         info = MQUEUE_I(inode);
1343 
1344         spin_lock(&info->lock);
1345 
1346         omqstat = info->attr;
1347         omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1348         if (u_mqstat) {
1349                 audit_mq_getsetattr(mqdes, &mqstat);
1350                 spin_lock(&f.file->f_lock);
1351                 if (mqstat.mq_flags & O_NONBLOCK)
1352                         f.file->f_flags |= O_NONBLOCK;
1353                 else
1354                         f.file->f_flags &= ~O_NONBLOCK;
1355                 spin_unlock(&f.file->f_lock);
1356 
1357                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1358         }
1359 
1360         spin_unlock(&info->lock);
1361 
1362         ret = 0;
1363         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1364                                                 sizeof(struct mq_attr)))
1365                 ret = -EFAULT;
1366 
1367 out_fput:
1368         fdput(f);
1369 out:
1370         return ret;
1371 }
1372 
1373 static const struct inode_operations mqueue_dir_inode_operations = {
1374         .lookup = simple_lookup,
1375         .create = mqueue_create,
1376         .unlink = mqueue_unlink,
1377 };
1378 
1379 static const struct file_operations mqueue_file_operations = {
1380         .flush = mqueue_flush_file,
1381         .poll = mqueue_poll_file,
1382         .read = mqueue_read_file,
1383         .llseek = default_llseek,
1384 };
1385 
1386 static const struct super_operations mqueue_super_ops = {
1387         .alloc_inode = mqueue_alloc_inode,
1388         .destroy_inode = mqueue_destroy_inode,
1389         .evict_inode = mqueue_evict_inode,
1390         .statfs = simple_statfs,
1391 };
1392 
1393 static struct file_system_type mqueue_fs_type = {
1394         .name = "mqueue",
1395         .mount = mqueue_mount,
1396         .kill_sb = kill_litter_super,
1397         .fs_flags = FS_USERNS_MOUNT,
1398 };
1399 
1400 int mq_init_ns(struct ipc_namespace *ns)
1401 {
1402         ns->mq_queues_count  = 0;
1403         ns->mq_queues_max    = DFLT_QUEUESMAX;
1404         ns->mq_msg_max       = DFLT_MSGMAX;
1405         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1406         ns->mq_msg_default   = DFLT_MSG;
1407         ns->mq_msgsize_default  = DFLT_MSGSIZE;
1408 
1409         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1410         if (IS_ERR(ns->mq_mnt)) {
1411                 int err = PTR_ERR(ns->mq_mnt);
1412                 ns->mq_mnt = NULL;
1413                 return err;
1414         }
1415         return 0;
1416 }
1417 
1418 void mq_clear_sbinfo(struct ipc_namespace *ns)
1419 {
1420         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1421 }
1422 
1423 void mq_put_mnt(struct ipc_namespace *ns)
1424 {
1425         kern_unmount(ns->mq_mnt);
1426 }
1427 
1428 static int __init init_mqueue_fs(void)
1429 {
1430         int error;
1431 
1432         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1433                                 sizeof(struct mqueue_inode_info), 0,
1434                                 SLAB_HWCACHE_ALIGN, init_once);
1435         if (mqueue_inode_cachep == NULL)
1436                 return -ENOMEM;
1437 
1438         /* ignore failures - they are not fatal */
1439         mq_sysctl_table = mq_register_sysctl_table();
1440 
1441         error = register_filesystem(&mqueue_fs_type);
1442         if (error)
1443                 goto out_sysctl;
1444 
1445         spin_lock_init(&mq_lock);
1446 
1447         error = mq_init_ns(&init_ipc_ns);
1448         if (error)
1449                 goto out_filesystem;
1450 
1451         return 0;
1452 
1453 out_filesystem:
1454         unregister_filesystem(&mqueue_fs_type);
1455 out_sysctl:
1456         if (mq_sysctl_table)
1457                 unregister_sysctl_table(mq_sysctl_table);
1458         kmem_cache_destroy(mqueue_inode_cachep);
1459         return error;
1460 }
1461 
1462 device_initcall(init_mqueue_fs);
1463 

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