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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / ipc / mqueue.c
blobd7f309f74dec243f295e211d60cd76a9088460f9
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 #include <linux/sched/wake_q.h>
39 #include <linux/sched/signal.h>
40 #include <linux/sched/user.h>
41
42 #include <net/sock.h>
43 #include "util.h"
44
45 #define MQUEUE_MAGIC 0x19800202
46 #define DIRENT_SIZE 20
47 #define FILENT_SIZE 80
48
49 #define SEND 0
50 #define RECV 1
51
52 #define STATE_NONE 0
53 #define STATE_READY 1
54
55 struct posix_msg_tree_node {
56 struct rb_node rb_node;
57 struct list_head msg_list;
58 int priority;
59 };
60
61 struct ext_wait_queue { /* queue of sleeping tasks */
62 struct task_struct *task;
63 struct list_head list;
64 struct msg_msg *msg; /* ptr of loaded message */
65 int state; /* one of STATE_* values */
66 };
67
68 struct mqueue_inode_info {
69 spinlock_t lock;
70 struct inode vfs_inode;
71 wait_queue_head_t wait_q;
72
73 struct rb_root msg_tree;
74 struct posix_msg_tree_node *node_cache;
75 struct mq_attr attr;
76
77 struct sigevent notify;
78 struct pid *notify_owner;
79 struct user_namespace *notify_user_ns;
80 struct user_struct *user; /* user who created, for accounting */
81 struct sock *notify_sock;
82 struct sk_buff *notify_cookie;
83
84 /* for tasks waiting for free space and messages, respectively */
85 struct ext_wait_queue e_wait_q[2];
86
87 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
88 };
89
90 static const struct inode_operations mqueue_dir_inode_operations;
91 static const struct file_operations mqueue_file_operations;
92 static const struct super_operations mqueue_super_ops;
93 static void remove_notification(struct mqueue_inode_info *info);
94
95 static struct kmem_cache *mqueue_inode_cachep;
96
97 static struct ctl_table_header *mq_sysctl_table;
98
99 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
100 {
101 return container_of(inode, struct mqueue_inode_info, vfs_inode);
102 }
103
104 /*
105 * This routine should be called with the mq_lock held.
106 */
107 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
108 {
109 return get_ipc_ns(inode->i_sb->s_fs_info);
110 }
111
112 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
113 {
114 struct ipc_namespace *ns;
115
116 spin_lock(&mq_lock);
117 ns = __get_ns_from_inode(inode);
118 spin_unlock(&mq_lock);
119 return ns;
120 }
121
122 /* Auxiliary functions to manipulate messages' list */
123 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
124 {
125 struct rb_node **p, *parent = NULL;
126 struct posix_msg_tree_node *leaf;
127
128 p = &info->msg_tree.rb_node;
129 while (*p) {
130 parent = *p;
131 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
132
133 if (likely(leaf->priority == msg->m_type))
134 goto insert_msg;
135 else if (msg->m_type < leaf->priority)
136 p = &(*p)->rb_left;
137 else
138 p = &(*p)->rb_right;
139 }
140 if (info->node_cache) {
141 leaf = info->node_cache;
142 info->node_cache = NULL;
143 } else {
144 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
145 if (!leaf)
146 return -ENOMEM;
147 INIT_LIST_HEAD(&leaf->msg_list);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152 insert_msg:
153 info->attr.mq_curmsgs++;
154 info->qsize += msg->m_ts;
155 list_add_tail(&msg->m_list, &leaf->msg_list);
156 return 0;
157 }
158
159 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
160 {
161 struct rb_node **p, *parent = NULL;
162 struct posix_msg_tree_node *leaf;
163 struct msg_msg *msg;
164
165 try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 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 kfree(leaf);
205 } else {
206 info->node_cache = leaf;
207 }
208 }
209 }
210 info->attr.mq_curmsgs--;
211 info->qsize -= msg->m_ts;
212 return msg;
213 }
214
215 static struct inode *mqueue_get_inode(struct super_block *sb,
216 struct ipc_namespace *ipc_ns, umode_t mode,
217 struct mq_attr *attr)
218 {
219 struct user_struct *u = current_user();
220 struct inode *inode;
221 int ret = -ENOMEM;
222
223 inode = new_inode(sb);
224 if (!inode)
225 goto err;
226
227 inode->i_ino = get_next_ino();
228 inode->i_mode = mode;
229 inode->i_uid = current_fsuid();
230 inode->i_gid = current_fsgid();
231 inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
232
233 if (S_ISREG(mode)) {
234 struct mqueue_inode_info *info;
235 unsigned long mq_bytes, mq_treesize;
236
237 inode->i_fop = &mqueue_file_operations;
238 inode->i_size = FILENT_SIZE;
239 /* mqueue specific info */
240 info = MQUEUE_I(inode);
241 spin_lock_init(&info->lock);
242 init_waitqueue_head(&info->wait_q);
243 INIT_LIST_HEAD(&info->e_wait_q[0].list);
244 INIT_LIST_HEAD(&info->e_wait_q[1].list);
245 info->notify_owner = NULL;
246 info->notify_user_ns = NULL;
247 info->qsize = 0;
248 info->user = NULL; /* set when all is ok */
249 info->msg_tree = RB_ROOT;
250 info->node_cache = NULL;
251 memset(&info->attr, 0, sizeof(info->attr));
252 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
253 ipc_ns->mq_msg_default);
254 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
255 ipc_ns->mq_msgsize_default);
256 if (attr) {
257 info->attr.mq_maxmsg = attr->mq_maxmsg;
258 info->attr.mq_msgsize = attr->mq_msgsize;
259 }
260 /*
261 * We used to allocate a static array of pointers and account
262 * the size of that array as well as one msg_msg struct per
263 * possible message into the queue size. That's no longer
264 * accurate as the queue is now an rbtree and will grow and
265 * shrink depending on usage patterns. We can, however, still
266 * account one msg_msg struct per message, but the nodes are
267 * allocated depending on priority usage, and most programs
268 * only use one, or a handful, of priorities. However, since
269 * this is pinned memory, we need to assume worst case, so
270 * that means the min(mq_maxmsg, max_priorities) * struct
271 * posix_msg_tree_node.
272 */
273
274 ret = -EINVAL;
275 if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
276 goto out_inode;
277 if (capable(CAP_SYS_RESOURCE)) {
278 if (info->attr.mq_maxmsg > HARD_MSGMAX ||
279 info->attr.mq_msgsize > HARD_MSGSIZEMAX)
280 goto out_inode;
281 } else {
282 if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
283 info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
284 goto out_inode;
285 }
286 ret = -EOVERFLOW;
287 /* check for overflow */
288 if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
289 goto out_inode;
290 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
291 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
292 sizeof(struct posix_msg_tree_node);
293 mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
294 if (mq_bytes + mq_treesize < mq_bytes)
295 goto out_inode;
296 mq_bytes += mq_treesize;
297 spin_lock(&mq_lock);
298 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
299 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
300 spin_unlock(&mq_lock);
301 /* mqueue_evict_inode() releases info->messages */
302 ret = -EMFILE;
303 goto out_inode;
304 }
305 u->mq_bytes += mq_bytes;
306 spin_unlock(&mq_lock);
307
308 /* all is ok */
309 info->user = get_uid(u);
310 } else if (S_ISDIR(mode)) {
311 inc_nlink(inode);
312 /* Some things misbehave if size == 0 on a directory */
313 inode->i_size = 2 * DIRENT_SIZE;
314 inode->i_op = &mqueue_dir_inode_operations;
315 inode->i_fop = &simple_dir_operations;
316 }
317
318 return inode;
319 out_inode:
320 iput(inode);
321 err:
322 return ERR_PTR(ret);
323 }
324
325 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
326 {
327 struct inode *inode;
328 struct ipc_namespace *ns = data;
329
330 sb->s_fs_info = ns;
331 sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
332 sb->s_blocksize = PAGE_SIZE;
333 sb->s_blocksize_bits = PAGE_SHIFT;
334 sb->s_magic = MQUEUE_MAGIC;
335 sb->s_op = &mqueue_super_ops;
336
337 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
338 if (IS_ERR(inode))
339 return PTR_ERR(inode);
340
341 sb->s_root = d_make_root(inode);
342 if (!sb->s_root)
343 return -ENOMEM;
344 return 0;
345 }
346
347 static struct file_system_type mqueue_fs_type;
348 /*
349 * Return value is pinned only by reference in ->mq_mnt; it will
350 * live until ipcns dies. Caller does not need to drop it.
351 */
352 static struct vfsmount *mq_internal_mount(void)
353 {
354 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
355 struct vfsmount *m = ns->mq_mnt;
356 if (m)
357 return m;
358 m = kern_mount_data(&mqueue_fs_type, ns);
359 spin_lock(&mq_lock);
360 if (unlikely(ns->mq_mnt)) {
361 spin_unlock(&mq_lock);
362 if (!IS_ERR(m))
363 kern_unmount(m);
364 return ns->mq_mnt;
365 }
366 if (!IS_ERR(m))
367 ns->mq_mnt = m;
368 spin_unlock(&mq_lock);
369 return m;
370 }
371
372 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
373 int flags, const char *dev_name,
374 void *data)
375 {
376 struct vfsmount *m;
377 if (flags & SB_KERNMOUNT)
378 return mount_nodev(fs_type, flags, data, mqueue_fill_super);
379 m = mq_internal_mount();
380 if (IS_ERR(m))
381 return ERR_CAST(m);
382 atomic_inc(&m->mnt_sb->s_active);
383 down_write(&m->mnt_sb->s_umount);
384 return dget(m->mnt_root);
385 }
386
387 static void init_once(void *foo)
388 {
389 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
390
391 inode_init_once(&p->vfs_inode);
392 }
393
394 static struct inode *mqueue_alloc_inode(struct super_block *sb)
395 {
396 struct mqueue_inode_info *ei;
397
398 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
399 if (!ei)
400 return NULL;
401 return &ei->vfs_inode;
402 }
403
404 static void mqueue_i_callback(struct rcu_head *head)
405 {
406 struct inode *inode = container_of(head, struct inode, i_rcu);
407 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
408 }
409
410 static void mqueue_destroy_inode(struct inode *inode)
411 {
412 call_rcu(&inode->i_rcu, mqueue_i_callback);
413 }
414
415 static void mqueue_evict_inode(struct inode *inode)
416 {
417 struct mqueue_inode_info *info;
418 struct user_struct *user;
419 unsigned long mq_bytes, mq_treesize;
420 struct ipc_namespace *ipc_ns;
421 struct msg_msg *msg;
422
423 clear_inode(inode);
424
425 if (S_ISDIR(inode->i_mode))
426 return;
427
428 ipc_ns = get_ns_from_inode(inode);
429 info = MQUEUE_I(inode);
430 spin_lock(&info->lock);
431 while ((msg = msg_get(info)) != NULL)
432 free_msg(msg);
433 kfree(info->node_cache);
434 spin_unlock(&info->lock);
435
436 /* Total amount of bytes accounted for the mqueue */
437 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
438 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
439 sizeof(struct posix_msg_tree_node);
440
441 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
442 info->attr.mq_msgsize);
443
444 user = info->user;
445 if (user) {
446 spin_lock(&mq_lock);
447 user->mq_bytes -= mq_bytes;
448 /*
449 * get_ns_from_inode() ensures that the
450 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
451 * to which we now hold a reference, or it is NULL.
452 * We can't put it here under mq_lock, though.
453 */
454 if (ipc_ns)
455 ipc_ns->mq_queues_count--;
456 spin_unlock(&mq_lock);
457 free_uid(user);
458 }
459 if (ipc_ns)
460 put_ipc_ns(ipc_ns);
461 }
462
463 static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
464 {
465 struct inode *dir = dentry->d_parent->d_inode;
466 struct inode *inode;
467 struct mq_attr *attr = arg;
468 int error;
469 struct ipc_namespace *ipc_ns;
470
471 spin_lock(&mq_lock);
472 ipc_ns = __get_ns_from_inode(dir);
473 if (!ipc_ns) {
474 error = -EACCES;
475 goto out_unlock;
476 }
477
478 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
479 !capable(CAP_SYS_RESOURCE)) {
480 error = -ENOSPC;
481 goto out_unlock;
482 }
483 ipc_ns->mq_queues_count++;
484 spin_unlock(&mq_lock);
485
486 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
487 if (IS_ERR(inode)) {
488 error = PTR_ERR(inode);
489 spin_lock(&mq_lock);
490 ipc_ns->mq_queues_count--;
491 goto out_unlock;
492 }
493
494 put_ipc_ns(ipc_ns);
495 dir->i_size += DIRENT_SIZE;
496 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
497
498 d_instantiate(dentry, inode);
499 dget(dentry);
500 return 0;
501 out_unlock:
502 spin_unlock(&mq_lock);
503 if (ipc_ns)
504 put_ipc_ns(ipc_ns);
505 return error;
506 }
507
508 static int mqueue_create(struct inode *dir, struct dentry *dentry,
509 umode_t mode, bool excl)
510 {
511 return mqueue_create_attr(dentry, mode, NULL);
512 }
513
514 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
515 {
516 struct inode *inode = d_inode(dentry);
517
518 dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
519 dir->i_size -= DIRENT_SIZE;
520 drop_nlink(inode);
521 dput(dentry);
522 return 0;
523 }
524
525 /*
526 * This is routine for system read from queue file.
527 * To avoid mess with doing here some sort of mq_receive we allow
528 * to read only queue size & notification info (the only values
529 * that are interesting from user point of view and aren't accessible
530 * through std routines)
531 */
532 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
533 size_t count, loff_t *off)
534 {
535 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
536 char buffer[FILENT_SIZE];
537 ssize_t ret;
538
539 spin_lock(&info->lock);
540 snprintf(buffer, sizeof(buffer),
541 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
542 info->qsize,
543 info->notify_owner ? info->notify.sigev_notify : 0,
544 (info->notify_owner &&
545 info->notify.sigev_notify == SIGEV_SIGNAL) ?
546 info->notify.sigev_signo : 0,
547 pid_vnr(info->notify_owner));
548 spin_unlock(&info->lock);
549 buffer[sizeof(buffer)-1] = '\0';
550
551 ret = simple_read_from_buffer(u_data, count, off, buffer,
552 strlen(buffer));
553 if (ret <= 0)
554 return ret;
555
556 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
557 return ret;
558 }
559
560 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
561 {
562 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
563
564 spin_lock(&info->lock);
565 if (task_tgid(current) == info->notify_owner)
566 remove_notification(info);
567
568 spin_unlock(&info->lock);
569 return 0;
570 }
571
572 static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
573 {
574 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
575 __poll_t retval = 0;
576
577 poll_wait(filp, &info->wait_q, poll_tab);
578
579 spin_lock(&info->lock);
580 if (info->attr.mq_curmsgs)
581 retval = EPOLLIN | EPOLLRDNORM;
582
583 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
584 retval |= EPOLLOUT | EPOLLWRNORM;
585 spin_unlock(&info->lock);
586
587 return retval;
588 }
589
590 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
591 static void wq_add(struct mqueue_inode_info *info, int sr,
592 struct ext_wait_queue *ewp)
593 {
594 struct ext_wait_queue *walk;
595
596 ewp->task = current;
597
598 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
599 if (walk->task->prio <= current->prio) {
600 list_add_tail(&ewp->list, &walk->list);
601 return;
602 }
603 }
604 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
605 }
606
607 /*
608 * Puts current task to sleep. Caller must hold queue lock. After return
609 * lock isn't held.
610 * sr: SEND or RECV
611 */
612 static int wq_sleep(struct mqueue_inode_info *info, int sr,
613 ktime_t *timeout, struct ext_wait_queue *ewp)
614 __releases(&info->lock)
615 {
616 int retval;
617 signed long time;
618
619 wq_add(info, sr, ewp);
620
621 for (;;) {
622 __set_current_state(TASK_INTERRUPTIBLE);
623
624 spin_unlock(&info->lock);
625 time = schedule_hrtimeout_range_clock(timeout, 0,
626 HRTIMER_MODE_ABS, CLOCK_REALTIME);
627
628 if (ewp->state == STATE_READY) {
629 retval = 0;
630 goto out;
631 }
632 spin_lock(&info->lock);
633 if (ewp->state == STATE_READY) {
634 retval = 0;
635 goto out_unlock;
636 }
637 if (signal_pending(current)) {
638 retval = -ERESTARTSYS;
639 break;
640 }
641 if (time == 0) {
642 retval = -ETIMEDOUT;
643 break;
644 }
645 }
646 list_del(&ewp->list);
647 out_unlock:
648 spin_unlock(&info->lock);
649 out:
650 return retval;
651 }
652
653 /*
654 * Returns waiting task that should be serviced first or NULL if none exists
655 */
656 static struct ext_wait_queue *wq_get_first_waiter(
657 struct mqueue_inode_info *info, int sr)
658 {
659 struct list_head *ptr;
660
661 ptr = info->e_wait_q[sr].list.prev;
662 if (ptr == &info->e_wait_q[sr].list)
663 return NULL;
664 return list_entry(ptr, struct ext_wait_queue, list);
665 }
666
667
668 static inline void set_cookie(struct sk_buff *skb, char code)
669 {
670 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
671 }
672
673 /*
674 * The next function is only to split too long sys_mq_timedsend
675 */
676 static void __do_notify(struct mqueue_inode_info *info)
677 {
678 /* notification
679 * invoked when there is registered process and there isn't process
680 * waiting synchronously for message AND state of queue changed from
681 * empty to not empty. Here we are sure that no one is waiting
682 * synchronously. */
683 if (info->notify_owner &&
684 info->attr.mq_curmsgs == 1) {
685 struct siginfo sig_i;
686 switch (info->notify.sigev_notify) {
687 case SIGEV_NONE:
688 break;
689 case SIGEV_SIGNAL:
690 /* sends signal */
691
692 clear_siginfo(&sig_i);
693 sig_i.si_signo = info->notify.sigev_signo;
694 sig_i.si_errno = 0;
695 sig_i.si_code = SI_MESGQ;
696 sig_i.si_value = info->notify.sigev_value;
697 /* map current pid/uid into info->owner's namespaces */
698 rcu_read_lock();
699 sig_i.si_pid = task_tgid_nr_ns(current,
700 ns_of_pid(info->notify_owner));
701 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
702 rcu_read_unlock();
703
704 kill_pid_info(info->notify.sigev_signo,
705 &sig_i, info->notify_owner);
706 break;
707 case SIGEV_THREAD:
708 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
709 netlink_sendskb(info->notify_sock, info->notify_cookie);
710 break;
711 }
712 /* after notification unregisters process */
713 put_pid(info->notify_owner);
714 put_user_ns(info->notify_user_ns);
715 info->notify_owner = NULL;
716 info->notify_user_ns = NULL;
717 }
718 wake_up(&info->wait_q);
719 }
720
721 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
722 struct timespec64 *ts)
723 {
724 if (get_timespec64(ts, u_abs_timeout))
725 return -EFAULT;
726 if (!timespec64_valid(ts))
727 return -EINVAL;
728 return 0;
729 }
730
731 static void remove_notification(struct mqueue_inode_info *info)
732 {
733 if (info->notify_owner != NULL &&
734 info->notify.sigev_notify == SIGEV_THREAD) {
735 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
736 netlink_sendskb(info->notify_sock, info->notify_cookie);
737 }
738 put_pid(info->notify_owner);
739 put_user_ns(info->notify_user_ns);
740 info->notify_owner = NULL;
741 info->notify_user_ns = NULL;
742 }
743
744 static int prepare_open(struct dentry *dentry, int oflag, int ro,
745 umode_t mode, struct filename *name,
746 struct mq_attr *attr)
747 {
748 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
749 MAY_READ | MAY_WRITE };
750 int acc;
751
752 if (d_really_is_negative(dentry)) {
753 if (!(oflag & O_CREAT))
754 return -ENOENT;
755 if (ro)
756 return ro;
757 audit_inode_parent_hidden(name, dentry->d_parent);
758 return vfs_mkobj(dentry, mode & ~current_umask(),
759 mqueue_create_attr, attr);
760 }
761 /* it already existed */
762 audit_inode(name, dentry, 0);
763 if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
764 return -EEXIST;
765 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
766 return -EINVAL;
767 acc = oflag2acc[oflag & O_ACCMODE];
768 return inode_permission(d_inode(dentry), acc);
769 }
770
771 static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
772 struct mq_attr *attr)
773 {
774 struct vfsmount *mnt = mq_internal_mount();
775 struct dentry *root;
776 struct filename *name;
777 struct path path;
778 int fd, error;
779 int ro;
780
781 if (IS_ERR(mnt))
782 return PTR_ERR(mnt);
783
784 audit_mq_open(oflag, mode, attr);
785
786 if (IS_ERR(name = getname(u_name)))
787 return PTR_ERR(name);
788
789 fd = get_unused_fd_flags(O_CLOEXEC);
790 if (fd < 0)
791 goto out_putname;
792
793 ro = mnt_want_write(mnt); /* we'll drop it in any case */
794 root = mnt->mnt_root;
795 inode_lock(d_inode(root));
796 path.dentry = lookup_one_len(name->name, root, strlen(name->name));
797 if (IS_ERR(path.dentry)) {
798 error = PTR_ERR(path.dentry);
799 goto out_putfd;
800 }
801 path.mnt = mntget(mnt);
802 error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
803 if (!error) {
804 struct file *file = dentry_open(&path, oflag, current_cred());
805 if (!IS_ERR(file))
806 fd_install(fd, file);
807 else
808 error = PTR_ERR(file);
809 }
810 path_put(&path);
811 out_putfd:
812 if (error) {
813 put_unused_fd(fd);
814 fd = error;
815 }
816 inode_unlock(d_inode(root));
817 if (!ro)
818 mnt_drop_write(mnt);
819 out_putname:
820 putname(name);
821 return fd;
822 }
823
824 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
825 struct mq_attr __user *, u_attr)
826 {
827 struct mq_attr attr;
828 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
829 return -EFAULT;
830
831 return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
832 }
833
834 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
835 {
836 int err;
837 struct filename *name;
838 struct dentry *dentry;
839 struct inode *inode = NULL;
840 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
841 struct vfsmount *mnt = ipc_ns->mq_mnt;
842
843 if (!mnt)
844 return -ENOENT;
845
846 name = getname(u_name);
847 if (IS_ERR(name))
848 return PTR_ERR(name);
849
850 audit_inode_parent_hidden(name, mnt->mnt_root);
851 err = mnt_want_write(mnt);
852 if (err)
853 goto out_name;
854 inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
855 dentry = lookup_one_len(name->name, mnt->mnt_root,
856 strlen(name->name));
857 if (IS_ERR(dentry)) {
858 err = PTR_ERR(dentry);
859 goto out_unlock;
860 }
861
862 inode = d_inode(dentry);
863 if (!inode) {
864 err = -ENOENT;
865 } else {
866 ihold(inode);
867 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
868 }
869 dput(dentry);
870
871 out_unlock:
872 inode_unlock(d_inode(mnt->mnt_root));
873 if (inode)
874 iput(inode);
875 mnt_drop_write(mnt);
876 out_name:
877 putname(name);
878
879 return err;
880 }
881
882 /* Pipelined send and receive functions.
883 *
884 * If a receiver finds no waiting message, then it registers itself in the
885 * list of waiting receivers. A sender checks that list before adding the new
886 * message into the message array. If there is a waiting receiver, then it
887 * bypasses the message array and directly hands the message over to the
888 * receiver. The receiver accepts the message and returns without grabbing the
889 * queue spinlock:
890 *
891 * - Set pointer to message.
892 * - Queue the receiver task for later wakeup (without the info->lock).
893 * - Update its state to STATE_READY. Now the receiver can continue.
894 * - Wake up the process after the lock is dropped. Should the process wake up
895 * before this wakeup (due to a timeout or a signal) it will either see
896 * STATE_READY and continue or acquire the lock to check the state again.
897 *
898 * The same algorithm is used for senders.
899 */
900
901 /* pipelined_send() - send a message directly to the task waiting in
902 * sys_mq_timedreceive() (without inserting message into a queue).
903 */
904 static inline void pipelined_send(struct wake_q_head *wake_q,
905 struct mqueue_inode_info *info,
906 struct msg_msg *message,
907 struct ext_wait_queue *receiver)
908 {
909 receiver->msg = message;
910 list_del(&receiver->list);
911 wake_q_add(wake_q, receiver->task);
912 /*
913 * Rely on the implicit cmpxchg barrier from wake_q_add such
914 * that we can ensure that updating receiver->state is the last
915 * write operation: As once set, the receiver can continue,
916 * and if we don't have the reference count from the wake_q,
917 * yet, at that point we can later have a use-after-free
918 * condition and bogus wakeup.
919 */
920 receiver->state = STATE_READY;
921 }
922
923 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
924 * gets its message and put to the queue (we have one free place for sure). */
925 static inline void pipelined_receive(struct wake_q_head *wake_q,
926 struct mqueue_inode_info *info)
927 {
928 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
929
930 if (!sender) {
931 /* for poll */
932 wake_up_interruptible(&info->wait_q);
933 return;
934 }
935 if (msg_insert(sender->msg, info))
936 return;
937
938 list_del(&sender->list);
939 wake_q_add(wake_q, sender->task);
940 sender->state = STATE_READY;
941 }
942
943 static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
944 size_t msg_len, unsigned int msg_prio,
945 struct timespec64 *ts)
946 {
947 struct fd f;
948 struct inode *inode;
949 struct ext_wait_queue wait;
950 struct ext_wait_queue *receiver;
951 struct msg_msg *msg_ptr;
952 struct mqueue_inode_info *info;
953 ktime_t expires, *timeout = NULL;
954 struct posix_msg_tree_node *new_leaf = NULL;
955 int ret = 0;
956 DEFINE_WAKE_Q(wake_q);
957
958 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
959 return -EINVAL;
960
961 if (ts) {
962 expires = timespec64_to_ktime(*ts);
963 timeout = &expires;
964 }
965
966 audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
967
968 f = fdget(mqdes);
969 if (unlikely(!f.file)) {
970 ret = -EBADF;
971 goto out;
972 }
973
974 inode = file_inode(f.file);
975 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
976 ret = -EBADF;
977 goto out_fput;
978 }
979 info = MQUEUE_I(inode);
980 audit_file(f.file);
981
982 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
983 ret = -EBADF;
984 goto out_fput;
985 }
986
987 if (unlikely(msg_len > info->attr.mq_msgsize)) {
988 ret = -EMSGSIZE;
989 goto out_fput;
990 }
991
992 /* First try to allocate memory, before doing anything with
993 * existing queues. */
994 msg_ptr = load_msg(u_msg_ptr, msg_len);
995 if (IS_ERR(msg_ptr)) {
996 ret = PTR_ERR(msg_ptr);
997 goto out_fput;
998 }
999 msg_ptr->m_ts = msg_len;
1000 msg_ptr->m_type = msg_prio;
1001
1002 /*
1003 * msg_insert really wants us to have a valid, spare node struct so
1004 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1005 * fall back to that if necessary.
1006 */
1007 if (!info->node_cache)
1008 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1009
1010 spin_lock(&info->lock);
1011
1012 if (!info->node_cache && new_leaf) {
1013 /* Save our speculative allocation into the cache */
1014 INIT_LIST_HEAD(&new_leaf->msg_list);
1015 info->node_cache = new_leaf;
1016 new_leaf = NULL;
1017 } else {
1018 kfree(new_leaf);
1019 }
1020
1021 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1022 if (f.file->f_flags & O_NONBLOCK) {
1023 ret = -EAGAIN;
1024 } else {
1025 wait.task = current;
1026 wait.msg = (void *) msg_ptr;
1027 wait.state = STATE_NONE;
1028 ret = wq_sleep(info, SEND, timeout, &wait);
1029 /*
1030 * wq_sleep must be called with info->lock held, and
1031 * returns with the lock released
1032 */
1033 goto out_free;
1034 }
1035 } else {
1036 receiver = wq_get_first_waiter(info, RECV);
1037 if (receiver) {
1038 pipelined_send(&wake_q, info, msg_ptr, receiver);
1039 } else {
1040 /* adds message to the queue */
1041 ret = msg_insert(msg_ptr, info);
1042 if (ret)
1043 goto out_unlock;
1044 __do_notify(info);
1045 }
1046 inode->i_atime = inode->i_mtime = inode->i_ctime =
1047 current_time(inode);
1048 }
1049 out_unlock:
1050 spin_unlock(&info->lock);
1051 wake_up_q(&wake_q);
1052 out_free:
1053 if (ret)
1054 free_msg(msg_ptr);
1055 out_fput:
1056 fdput(f);
1057 out:
1058 return ret;
1059 }
1060
1061 static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1062 size_t msg_len, unsigned int __user *u_msg_prio,
1063 struct timespec64 *ts)
1064 {
1065 ssize_t ret;
1066 struct msg_msg *msg_ptr;
1067 struct fd f;
1068 struct inode *inode;
1069 struct mqueue_inode_info *info;
1070 struct ext_wait_queue wait;
1071 ktime_t expires, *timeout = NULL;
1072 struct posix_msg_tree_node *new_leaf = NULL;
1073
1074 if (ts) {
1075 expires = timespec64_to_ktime(*ts);
1076 timeout = &expires;
1077 }
1078
1079 audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1080
1081 f = fdget(mqdes);
1082 if (unlikely(!f.file)) {
1083 ret = -EBADF;
1084 goto out;
1085 }
1086
1087 inode = file_inode(f.file);
1088 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1089 ret = -EBADF;
1090 goto out_fput;
1091 }
1092 info = MQUEUE_I(inode);
1093 audit_file(f.file);
1094
1095 if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1096 ret = -EBADF;
1097 goto out_fput;
1098 }
1099
1100 /* checks if buffer is big enough */
1101 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1102 ret = -EMSGSIZE;
1103 goto out_fput;
1104 }
1105
1106 /*
1107 * msg_insert really wants us to have a valid, spare node struct so
1108 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1109 * fall back to that if necessary.
1110 */
1111 if (!info->node_cache)
1112 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1113
1114 spin_lock(&info->lock);
1115
1116 if (!info->node_cache && new_leaf) {
1117 /* Save our speculative allocation into the cache */
1118 INIT_LIST_HEAD(&new_leaf->msg_list);
1119 info->node_cache = new_leaf;
1120 } else {
1121 kfree(new_leaf);
1122 }
1123
1124 if (info->attr.mq_curmsgs == 0) {
1125 if (f.file->f_flags & O_NONBLOCK) {
1126 spin_unlock(&info->lock);
1127 ret = -EAGAIN;
1128 } else {
1129 wait.task = current;
1130 wait.state = STATE_NONE;
1131 ret = wq_sleep(info, RECV, timeout, &wait);
1132 msg_ptr = wait.msg;
1133 }
1134 } else {
1135 DEFINE_WAKE_Q(wake_q);
1136
1137 msg_ptr = msg_get(info);
1138
1139 inode->i_atime = inode->i_mtime = inode->i_ctime =
1140 current_time(inode);
1141
1142 /* There is now free space in queue. */
1143 pipelined_receive(&wake_q, info);
1144 spin_unlock(&info->lock);
1145 wake_up_q(&wake_q);
1146 ret = 0;
1147 }
1148 if (ret == 0) {
1149 ret = msg_ptr->m_ts;
1150
1151 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1152 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1153 ret = -EFAULT;
1154 }
1155 free_msg(msg_ptr);
1156 }
1157 out_fput:
1158 fdput(f);
1159 out:
1160 return ret;
1161 }
1162
1163 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1164 size_t, msg_len, unsigned int, msg_prio,
1165 const struct timespec __user *, u_abs_timeout)
1166 {
1167 struct timespec64 ts, *p = NULL;
1168 if (u_abs_timeout) {
1169 int res = prepare_timeout(u_abs_timeout, &ts);
1170 if (res)
1171 return res;
1172 p = &ts;
1173 }
1174 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1175 }
1176
1177 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1178 size_t, msg_len, unsigned int __user *, u_msg_prio,
1179 const struct timespec __user *, u_abs_timeout)
1180 {
1181 struct timespec64 ts, *p = NULL;
1182 if (u_abs_timeout) {
1183 int res = prepare_timeout(u_abs_timeout, &ts);
1184 if (res)
1185 return res;
1186 p = &ts;
1187 }
1188 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1189 }
1190
1191 /*
1192 * Notes: the case when user wants us to deregister (with NULL as pointer)
1193 * and he isn't currently owner of notification, will be silently discarded.
1194 * It isn't explicitly defined in the POSIX.
1195 */
1196 static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1197 {
1198 int ret;
1199 struct fd f;
1200 struct sock *sock;
1201 struct inode *inode;
1202 struct mqueue_inode_info *info;
1203 struct sk_buff *nc;
1204
1205 audit_mq_notify(mqdes, notification);
1206
1207 nc = NULL;
1208 sock = NULL;
1209 if (notification != NULL) {
1210 if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1211 notification->sigev_notify != SIGEV_SIGNAL &&
1212 notification->sigev_notify != SIGEV_THREAD))
1213 return -EINVAL;
1214 if (notification->sigev_notify == SIGEV_SIGNAL &&
1215 !valid_signal(notification->sigev_signo)) {
1216 return -EINVAL;
1217 }
1218 if (notification->sigev_notify == SIGEV_THREAD) {
1219 long timeo;
1220
1221 /* create the notify skb */
1222 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1223 if (!nc) {
1224 ret = -ENOMEM;
1225 goto out;
1226 }
1227 if (copy_from_user(nc->data,
1228 notification->sigev_value.sival_ptr,
1229 NOTIFY_COOKIE_LEN)) {
1230 ret = -EFAULT;
1231 goto out;
1232 }
1233
1234 /* TODO: add a header? */
1235 skb_put(nc, NOTIFY_COOKIE_LEN);
1236 /* and attach it to the socket */
1237 retry:
1238 f = fdget(notification->sigev_signo);
1239 if (!f.file) {
1240 ret = -EBADF;
1241 goto out;
1242 }
1243 sock = netlink_getsockbyfilp(f.file);
1244 fdput(f);
1245 if (IS_ERR(sock)) {
1246 ret = PTR_ERR(sock);
1247 sock = NULL;
1248 goto out;
1249 }
1250
1251 timeo = MAX_SCHEDULE_TIMEOUT;
1252 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1253 if (ret == 1) {
1254 sock = NULL;
1255 goto retry;
1256 }
1257 if (ret) {
1258 sock = NULL;
1259 nc = NULL;
1260 goto out;
1261 }
1262 }
1263 }
1264
1265 f = fdget(mqdes);
1266 if (!f.file) {
1267 ret = -EBADF;
1268 goto out;
1269 }
1270
1271 inode = file_inode(f.file);
1272 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1273 ret = -EBADF;
1274 goto out_fput;
1275 }
1276 info = MQUEUE_I(inode);
1277
1278 ret = 0;
1279 spin_lock(&info->lock);
1280 if (notification == NULL) {
1281 if (info->notify_owner == task_tgid(current)) {
1282 remove_notification(info);
1283 inode->i_atime = inode->i_ctime = current_time(inode);
1284 }
1285 } else if (info->notify_owner != NULL) {
1286 ret = -EBUSY;
1287 } else {
1288 switch (notification->sigev_notify) {
1289 case SIGEV_NONE:
1290 info->notify.sigev_notify = SIGEV_NONE;
1291 break;
1292 case SIGEV_THREAD:
1293 info->notify_sock = sock;
1294 info->notify_cookie = nc;
1295 sock = NULL;
1296 nc = NULL;
1297 info->notify.sigev_notify = SIGEV_THREAD;
1298 break;
1299 case SIGEV_SIGNAL:
1300 info->notify.sigev_signo = notification->sigev_signo;
1301 info->notify.sigev_value = notification->sigev_value;
1302 info->notify.sigev_notify = SIGEV_SIGNAL;
1303 break;
1304 }
1305
1306 info->notify_owner = get_pid(task_tgid(current));
1307 info->notify_user_ns = get_user_ns(current_user_ns());
1308 inode->i_atime = inode->i_ctime = current_time(inode);
1309 }
1310 spin_unlock(&info->lock);
1311 out_fput:
1312 fdput(f);
1313 out:
1314 if (sock)
1315 netlink_detachskb(sock, nc);
1316 else if (nc)
1317 dev_kfree_skb(nc);
1318
1319 return ret;
1320 }
1321
1322 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1323 const struct sigevent __user *, u_notification)
1324 {
1325 struct sigevent n, *p = NULL;
1326 if (u_notification) {
1327 if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1328 return -EFAULT;
1329 p = &n;
1330 }
1331 return do_mq_notify(mqdes, p);
1332 }
1333
1334 static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1335 {
1336 struct fd f;
1337 struct inode *inode;
1338 struct mqueue_inode_info *info;
1339
1340 if (new && (new->mq_flags & (~O_NONBLOCK)))
1341 return -EINVAL;
1342
1343 f = fdget(mqdes);
1344 if (!f.file)
1345 return -EBADF;
1346
1347 if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1348 fdput(f);
1349 return -EBADF;
1350 }
1351
1352 inode = file_inode(f.file);
1353 info = MQUEUE_I(inode);
1354
1355 spin_lock(&info->lock);
1356
1357 if (old) {
1358 *old = info->attr;
1359 old->mq_flags = f.file->f_flags & O_NONBLOCK;
1360 }
1361 if (new) {
1362 audit_mq_getsetattr(mqdes, new);
1363 spin_lock(&f.file->f_lock);
1364 if (new->mq_flags & O_NONBLOCK)
1365 f.file->f_flags |= O_NONBLOCK;
1366 else
1367 f.file->f_flags &= ~O_NONBLOCK;
1368 spin_unlock(&f.file->f_lock);
1369
1370 inode->i_atime = inode->i_ctime = current_time(inode);
1371 }
1372
1373 spin_unlock(&info->lock);
1374 fdput(f);
1375 return 0;
1376 }
1377
1378 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1379 const struct mq_attr __user *, u_mqstat,
1380 struct mq_attr __user *, u_omqstat)
1381 {
1382 int ret;
1383 struct mq_attr mqstat, omqstat;
1384 struct mq_attr *new = NULL, *old = NULL;
1385
1386 if (u_mqstat) {
1387 new = &mqstat;
1388 if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1389 return -EFAULT;
1390 }
1391 if (u_omqstat)
1392 old = &omqstat;
1393
1394 ret = do_mq_getsetattr(mqdes, new, old);
1395 if (ret || !old)
1396 return ret;
1397
1398 if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1399 return -EFAULT;
1400 return 0;
1401 }
1402
1403 #ifdef CONFIG_COMPAT
1404
1405 struct compat_mq_attr {
1406 compat_long_t mq_flags; /* message queue flags */
1407 compat_long_t mq_maxmsg; /* maximum number of messages */
1408 compat_long_t mq_msgsize; /* maximum message size */
1409 compat_long_t mq_curmsgs; /* number of messages currently queued */
1410 compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1411 };
1412
1413 static inline int get_compat_mq_attr(struct mq_attr *attr,
1414 const struct compat_mq_attr __user *uattr)
1415 {
1416 struct compat_mq_attr v;
1417
1418 if (copy_from_user(&v, uattr, sizeof(*uattr)))
1419 return -EFAULT;
1420
1421 memset(attr, 0, sizeof(*attr));
1422 attr->mq_flags = v.mq_flags;
1423 attr->mq_maxmsg = v.mq_maxmsg;
1424 attr->mq_msgsize = v.mq_msgsize;
1425 attr->mq_curmsgs = v.mq_curmsgs;
1426 return 0;
1427 }
1428
1429 static inline int put_compat_mq_attr(const struct mq_attr *attr,
1430 struct compat_mq_attr __user *uattr)
1431 {
1432 struct compat_mq_attr v;
1433
1434 memset(&v, 0, sizeof(v));
1435 v.mq_flags = attr->mq_flags;
1436 v.mq_maxmsg = attr->mq_maxmsg;
1437 v.mq_msgsize = attr->mq_msgsize;
1438 v.mq_curmsgs = attr->mq_curmsgs;
1439 if (copy_to_user(uattr, &v, sizeof(*uattr)))
1440 return -EFAULT;
1441 return 0;
1442 }
1443
1444 COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1445 int, oflag, compat_mode_t, mode,
1446 struct compat_mq_attr __user *, u_attr)
1447 {
1448 struct mq_attr attr, *p = NULL;
1449 if (u_attr && oflag & O_CREAT) {
1450 p = &attr;
1451 if (get_compat_mq_attr(&attr, u_attr))
1452 return -EFAULT;
1453 }
1454 return do_mq_open(u_name, oflag, mode, p);
1455 }
1456
1457 static int compat_prepare_timeout(const struct compat_timespec __user *p,
1458 struct timespec64 *ts)
1459 {
1460 if (compat_get_timespec64(ts, p))
1461 return -EFAULT;
1462 if (!timespec64_valid(ts))
1463 return -EINVAL;
1464 return 0;
1465 }
1466
1467 COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1468 const char __user *, u_msg_ptr,
1469 compat_size_t, msg_len, unsigned int, msg_prio,
1470 const struct compat_timespec __user *, u_abs_timeout)
1471 {
1472 struct timespec64 ts, *p = NULL;
1473 if (u_abs_timeout) {
1474 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1475 if (res)
1476 return res;
1477 p = &ts;
1478 }
1479 return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1480 }
1481
1482 COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1483 char __user *, u_msg_ptr,
1484 compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1485 const struct compat_timespec __user *, u_abs_timeout)
1486 {
1487 struct timespec64 ts, *p = NULL;
1488 if (u_abs_timeout) {
1489 int res = compat_prepare_timeout(u_abs_timeout, &ts);
1490 if (res)
1491 return res;
1492 p = &ts;
1493 }
1494 return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1495 }
1496
1497 COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1498 const struct compat_sigevent __user *, u_notification)
1499 {
1500 struct sigevent n, *p = NULL;
1501 if (u_notification) {
1502 if (get_compat_sigevent(&n, u_notification))
1503 return -EFAULT;
1504 if (n.sigev_notify == SIGEV_THREAD)
1505 n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1506 p = &n;
1507 }
1508 return do_mq_notify(mqdes, p);
1509 }
1510
1511 COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1512 const struct compat_mq_attr __user *, u_mqstat,
1513 struct compat_mq_attr __user *, u_omqstat)
1514 {
1515 int ret;
1516 struct mq_attr mqstat, omqstat;
1517 struct mq_attr *new = NULL, *old = NULL;
1518
1519 if (u_mqstat) {
1520 new = &mqstat;
1521 if (get_compat_mq_attr(new, u_mqstat))
1522 return -EFAULT;
1523 }
1524 if (u_omqstat)
1525 old = &omqstat;
1526
1527 ret = do_mq_getsetattr(mqdes, new, old);
1528 if (ret || !old)
1529 return ret;
1530
1531 if (put_compat_mq_attr(old, u_omqstat))
1532 return -EFAULT;
1533 return 0;
1534 }
1535 #endif
1536
1537 static const struct inode_operations mqueue_dir_inode_operations = {
1538 .lookup = simple_lookup,
1539 .create = mqueue_create,
1540 .unlink = mqueue_unlink,
1541 };
1542
1543 static const struct file_operations mqueue_file_operations = {
1544 .flush = mqueue_flush_file,
1545 .poll = mqueue_poll_file,
1546 .read = mqueue_read_file,
1547 .llseek = default_llseek,
1548 };
1549
1550 static const struct super_operations mqueue_super_ops = {
1551 .alloc_inode = mqueue_alloc_inode,
1552 .destroy_inode = mqueue_destroy_inode,
1553 .evict_inode = mqueue_evict_inode,
1554 .statfs = simple_statfs,
1555 };
1556
1557 static struct file_system_type mqueue_fs_type = {
1558 .name = "mqueue",
1559 .mount = mqueue_mount,
1560 .kill_sb = kill_litter_super,
1561 .fs_flags = FS_USERNS_MOUNT,
1562 };
1563
1564 int mq_init_ns(struct ipc_namespace *ns)
1565 {
1566 ns->mq_queues_count = 0;
1567 ns->mq_queues_max = DFLT_QUEUESMAX;
1568 ns->mq_msg_max = DFLT_MSGMAX;
1569 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1570 ns->mq_msg_default = DFLT_MSG;
1571 ns->mq_msgsize_default = DFLT_MSGSIZE;
1572 ns->mq_mnt = NULL;
1573
1574 return 0;
1575 }
1576
1577 void mq_clear_sbinfo(struct ipc_namespace *ns)
1578 {
1579 if (ns->mq_mnt)
1580 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1581 }
1582
1583 void mq_put_mnt(struct ipc_namespace *ns)
1584 {
1585 if (ns->mq_mnt)
1586 kern_unmount(ns->mq_mnt);
1587 }
1588
1589 static int __init init_mqueue_fs(void)
1590 {
1591 struct vfsmount *m;
1592 int error;
1593
1594 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1595 sizeof(struct mqueue_inode_info), 0,
1596 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1597 if (mqueue_inode_cachep == NULL)
1598 return -ENOMEM;
1599
1600 /* ignore failures - they are not fatal */
1601 mq_sysctl_table = mq_register_sysctl_table();
1602
1603 error = register_filesystem(&mqueue_fs_type);
1604 if (error)
1605 goto out_sysctl;
1606
1607 spin_lock_init(&mq_lock);
1608
1609 error = mq_init_ns(&init_ipc_ns);
1610 if (error)
1611 goto out_filesystem;
1612
1613 m = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1614 if (IS_ERR(m))
1615 goto out_filesystem;
1616 init_ipc_ns.mq_mnt = m;
1617 return 0;
1618
1619 out_filesystem:
1620 unregister_filesystem(&mqueue_fs_type);
1621 out_sysctl:
1622 if (mq_sysctl_table)
1623 unregister_sysctl_table(mq_sysctl_table);
1624 kmem_cache_destroy(mqueue_inode_cachep);
1625 return error;
1626 }
1627
1628 device_initcall(init_mqueue_fs);
CRIS linux kernel tree