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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
53struct posix_msg_tree_node {
54 struct rb_node rb_node;
55 struct list_head msg_list;
56 int priority;
57};
58
59struct 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
66struct 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
88static const struct inode_operations mqueue_dir_inode_operations;
89static const struct file_operations mqueue_file_operations;
90static const struct super_operations mqueue_super_ops;
91static void remove_notification(struct mqueue_inode_info *info);
92
93static struct kmem_cache *mqueue_inode_cachep;
94
95static struct ctl_table_header * mq_sysctl_table;
96
97static 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 */
105static 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
110static 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 */
121static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
122{
123 struct rb_node **p, *parent = NULL;
124 struct posix_msg_tree_node *leaf;
125
126 p = &info->msg_tree.rb_node;
127 while (*p) {
128 parent = *p;
129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
130
131 if (likely(leaf->priority == msg->m_type))
132 goto insert_msg;
133 else if (msg->m_type < leaf->priority)
134 p = &(*p)->rb_left;
135 else
136 p = &(*p)->rb_right;
137 }
138 if (info->node_cache) {
139 leaf = info->node_cache;
140 info->node_cache = NULL;
141 } else {
142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
143 if (!leaf)
144 return -ENOMEM;
145 rb_init_node(&leaf->rb_node);
146 INIT_LIST_HEAD(&leaf->msg_list);
147 info->qsize += sizeof(*leaf);
148 }
149 leaf->priority = msg->m_type;
150 rb_link_node(&leaf->rb_node, parent, p);
151 rb_insert_color(&leaf->rb_node, &info->msg_tree);
152insert_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
159static 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
165try_again:
166 p = &info->msg_tree.rb_node;
167 while (*p) {
168 parent = *p;
169 /*
170 * During insert, low priorities go to the left and high to the
171 * right. On receive, we want the highest priorities first, so
172 * walk all the way to the right.
173 */
174 p = &(*p)->rb_right;
175 }
176 if (!parent) {
177 if (info->attr.mq_curmsgs) {
178 pr_warn_once("Inconsistency in POSIX message queue, "
179 "no tree element, but supposedly messages "
180 "should exist!\n");
181 info->attr.mq_curmsgs = 0;
182 }
183 return NULL;
184 }
185 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
186 if (unlikely(list_empty(&leaf->msg_list))) {
187 pr_warn_once("Inconsistency in POSIX message queue, "
188 "empty leaf node but we haven't implemented "
189 "lazy leaf delete!\n");
190 rb_erase(&leaf->rb_node, &info->msg_tree);
191 if (info->node_cache) {
192 info->qsize -= sizeof(*leaf);
193 kfree(leaf);
194 } else {
195 info->node_cache = leaf;
196 }
197 goto try_again;
198 } else {
199 msg = list_first_entry(&leaf->msg_list,
200 struct msg_msg, m_list);
201 list_del(&msg->m_list);
202 if (list_empty(&leaf->msg_list)) {
203 rb_erase(&leaf->rb_node, &info->msg_tree);
204 if (info->node_cache) {
205 info->qsize -= sizeof(*leaf);
206 kfree(leaf);
207 } else {
208 info->node_cache = leaf;
209 }
210 }
211 }
212 info->attr.mq_curmsgs--;
213 info->qsize -= msg->m_ts;
214 return msg;
215}
216
217static struct inode *mqueue_get_inode(struct super_block *sb,
218 struct ipc_namespace *ipc_ns, umode_t mode,
219 struct mq_attr *attr)
220{
221 struct user_struct *u = current_user();
222 struct inode *inode;
223 int ret = -ENOMEM;
224
225 inode = new_inode(sb);
226 if (!inode)
227 goto err;
228
229 inode->i_ino = get_next_ino();
230 inode->i_mode = mode;
231 inode->i_uid = current_fsuid();
232 inode->i_gid = current_fsgid();
233 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
234
235 if (S_ISREG(mode)) {
236 struct mqueue_inode_info *info;
237 unsigned long mq_bytes, mq_treesize;
238
239 inode->i_fop = &mqueue_file_operations;
240 inode->i_size = FILENT_SIZE;
241 /* mqueue specific info */
242 info = MQUEUE_I(inode);
243 spin_lock_init(&info->lock);
244 init_waitqueue_head(&info->wait_q);
245 INIT_LIST_HEAD(&info->e_wait_q[0].list);
246 INIT_LIST_HEAD(&info->e_wait_q[1].list);
247 info->notify_owner = NULL;
248 info->notify_user_ns = NULL;
249 info->qsize = 0;
250 info->user = NULL; /* set when all is ok */
251 info->msg_tree = RB_ROOT;
252 info->node_cache = NULL;
253 memset(&info->attr, 0, sizeof(info->attr));
254 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
255 ipc_ns->mq_msg_default);
256 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
257 ipc_ns->mq_msgsize_default);
258 if (attr) {
259 info->attr.mq_maxmsg = attr->mq_maxmsg;
260 info->attr.mq_msgsize = attr->mq_msgsize;
261 }
262 /*
263 * We used to allocate a static array of pointers and account
264 * the size of that array as well as one msg_msg struct per
265 * possible message into the queue size. That's no longer
266 * accurate as the queue is now an rbtree and will grow and
267 * shrink depending on usage patterns. We can, however, still
268 * account one msg_msg struct per message, but the nodes are
269 * allocated depending on priority usage, and most programs
270 * only use one, or a handful, of priorities. However, since
271 * this is pinned memory, we need to assume worst case, so
272 * that means the min(mq_maxmsg, max_priorities) * struct
273 * posix_msg_tree_node.
274 */
275 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
276 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
277 sizeof(struct posix_msg_tree_node);
278
279 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
280 info->attr.mq_msgsize);
281
282 spin_lock(&mq_lock);
283 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
284 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
285 spin_unlock(&mq_lock);
286 /* mqueue_evict_inode() releases info->messages */
287 ret = -EMFILE;
288 goto out_inode;
289 }
290 u->mq_bytes += mq_bytes;
291 spin_unlock(&mq_lock);
292
293 /* all is ok */
294 info->user = get_uid(u);
295 } else if (S_ISDIR(mode)) {
296 inc_nlink(inode);
297 /* Some things misbehave if size == 0 on a directory */
298 inode->i_size = 2 * DIRENT_SIZE;
299 inode->i_op = &mqueue_dir_inode_operations;
300 inode->i_fop = &simple_dir_operations;
301 }
302
303 return inode;
304out_inode:
305 iput(inode);
306err:
307 return ERR_PTR(ret);
308}
309
310static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
311{
312 struct inode *inode;
313 struct ipc_namespace *ns = data;
314
315 sb->s_blocksize = PAGE_CACHE_SIZE;
316 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
317 sb->s_magic = MQUEUE_MAGIC;
318 sb->s_op = &mqueue_super_ops;
319
320 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
321 if (IS_ERR(inode))
322 return PTR_ERR(inode);
323
324 sb->s_root = d_make_root(inode);
325 if (!sb->s_root)
326 return -ENOMEM;
327 return 0;
328}
329
330static struct dentry *mqueue_mount(struct file_system_type *fs_type,
331 int flags, const char *dev_name,
332 void *data)
333{
334 if (!(flags & MS_KERNMOUNT))
335 data = current->nsproxy->ipc_ns;
336 return mount_ns(fs_type, flags, data, mqueue_fill_super);
337}
338
339static void init_once(void *foo)
340{
341 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
342
343 inode_init_once(&p->vfs_inode);
344}
345
346static struct inode *mqueue_alloc_inode(struct super_block *sb)
347{
348 struct mqueue_inode_info *ei;
349
350 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
351 if (!ei)
352 return NULL;
353 return &ei->vfs_inode;
354}
355
356static void mqueue_i_callback(struct rcu_head *head)
357{
358 struct inode *inode = container_of(head, struct inode, i_rcu);
359 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
360}
361
362static void mqueue_destroy_inode(struct inode *inode)
363{
364 call_rcu(&inode->i_rcu, mqueue_i_callback);
365}
366
367static void mqueue_evict_inode(struct inode *inode)
368{
369 struct mqueue_inode_info *info;
370 struct user_struct *user;
371 unsigned long mq_bytes, mq_treesize;
372 struct ipc_namespace *ipc_ns;
373 struct msg_msg *msg;
374
375 clear_inode(inode);
376
377 if (S_ISDIR(inode->i_mode))
378 return;
379
380 ipc_ns = get_ns_from_inode(inode);
381 info = MQUEUE_I(inode);
382 spin_lock(&info->lock);
383 while ((msg = msg_get(info)) != NULL)
384 free_msg(msg);
385 kfree(info->node_cache);
386 spin_unlock(&info->lock);
387
388 /* Total amount of bytes accounted for the mqueue */
389 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
390 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
391 sizeof(struct posix_msg_tree_node);
392
393 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
394 info->attr.mq_msgsize);
395
396 user = info->user;
397 if (user) {
398 spin_lock(&mq_lock);
399 user->mq_bytes -= mq_bytes;
400 /*
401 * get_ns_from_inode() ensures that the
402 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
403 * to which we now hold a reference, or it is NULL.
404 * We can't put it here under mq_lock, though.
405 */
406 if (ipc_ns)
407 ipc_ns->mq_queues_count--;
408 spin_unlock(&mq_lock);
409 free_uid(user);
410 }
411 if (ipc_ns)
412 put_ipc_ns(ipc_ns);
413}
414
415static int mqueue_create(struct inode *dir, struct dentry *dentry,
416 umode_t mode, struct nameidata *nd)
417{
418 struct inode *inode;
419 struct mq_attr *attr = dentry->d_fsdata;
420 int error;
421 struct ipc_namespace *ipc_ns;
422
423 spin_lock(&mq_lock);
424 ipc_ns = __get_ns_from_inode(dir);
425 if (!ipc_ns) {
426 error = -EACCES;
427 goto out_unlock;
428 }
429 if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
430 (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
431 !capable(CAP_SYS_RESOURCE))) {
432 error = -ENOSPC;
433 goto out_unlock;
434 }
435 ipc_ns->mq_queues_count++;
436 spin_unlock(&mq_lock);
437
438 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
439 if (IS_ERR(inode)) {
440 error = PTR_ERR(inode);
441 spin_lock(&mq_lock);
442 ipc_ns->mq_queues_count--;
443 goto out_unlock;
444 }
445
446 put_ipc_ns(ipc_ns);
447 dir->i_size += DIRENT_SIZE;
448 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
449
450 d_instantiate(dentry, inode);
451 dget(dentry);
452 return 0;
453out_unlock:
454 spin_unlock(&mq_lock);
455 if (ipc_ns)
456 put_ipc_ns(ipc_ns);
457 return error;
458}
459
460static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
461{
462 struct inode *inode = dentry->d_inode;
463
464 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
465 dir->i_size -= DIRENT_SIZE;
466 drop_nlink(inode);
467 dput(dentry);
468 return 0;
469}
470
471/*
472* This is routine for system read from queue file.
473* To avoid mess with doing here some sort of mq_receive we allow
474* to read only queue size & notification info (the only values
475* that are interesting from user point of view and aren't accessible
476* through std routines)
477*/
478static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
479 size_t count, loff_t *off)
480{
481 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
482 char buffer[FILENT_SIZE];
483 ssize_t ret;
484
485 spin_lock(&info->lock);
486 snprintf(buffer, sizeof(buffer),
487 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
488 info->qsize,
489 info->notify_owner ? info->notify.sigev_notify : 0,
490 (info->notify_owner &&
491 info->notify.sigev_notify == SIGEV_SIGNAL) ?
492 info->notify.sigev_signo : 0,
493 pid_vnr(info->notify_owner));
494 spin_unlock(&info->lock);
495 buffer[sizeof(buffer)-1] = '\0';
496
497 ret = simple_read_from_buffer(u_data, count, off, buffer,
498 strlen(buffer));
499 if (ret <= 0)
500 return ret;
501
502 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
503 return ret;
504}
505
506static int mqueue_flush_file(struct file *filp, fl_owner_t id)
507{
508 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
509
510 spin_lock(&info->lock);
511 if (task_tgid(current) == info->notify_owner)
512 remove_notification(info);
513
514 spin_unlock(&info->lock);
515 return 0;
516}
517
518static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
519{
520 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
521 int retval = 0;
522
523 poll_wait(filp, &info->wait_q, poll_tab);
524
525 spin_lock(&info->lock);
526 if (info->attr.mq_curmsgs)
527 retval = POLLIN | POLLRDNORM;
528
529 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
530 retval |= POLLOUT | POLLWRNORM;
531 spin_unlock(&info->lock);
532
533 return retval;
534}
535
536/* Adds current to info->e_wait_q[sr] before element with smaller prio */
537static void wq_add(struct mqueue_inode_info *info, int sr,
538 struct ext_wait_queue *ewp)
539{
540 struct ext_wait_queue *walk;
541
542 ewp->task = current;
543
544 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
545 if (walk->task->static_prio <= current->static_prio) {
546 list_add_tail(&ewp->list, &walk->list);
547 return;
548 }
549 }
550 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
551}
552
553/*
554 * Puts current task to sleep. Caller must hold queue lock. After return
555 * lock isn't held.
556 * sr: SEND or RECV
557 */
558static int wq_sleep(struct mqueue_inode_info *info, int sr,
559 ktime_t *timeout, struct ext_wait_queue *ewp)
560{
561 int retval;
562 signed long time;
563
564 wq_add(info, sr, ewp);
565
566 for (;;) {
567 set_current_state(TASK_INTERRUPTIBLE);
568
569 spin_unlock(&info->lock);
570 time = schedule_hrtimeout_range_clock(timeout, 0,
571 HRTIMER_MODE_ABS, CLOCK_REALTIME);
572
573 while (ewp->state == STATE_PENDING)
574 cpu_relax();
575
576 if (ewp->state == STATE_READY) {
577 retval = 0;
578 goto out;
579 }
580 spin_lock(&info->lock);
581 if (ewp->state == STATE_READY) {
582 retval = 0;
583 goto out_unlock;
584 }
585 if (signal_pending(current)) {
586 retval = -ERESTARTSYS;
587 break;
588 }
589 if (time == 0) {
590 retval = -ETIMEDOUT;
591 break;
592 }
593 }
594 list_del(&ewp->list);
595out_unlock:
596 spin_unlock(&info->lock);
597out:
598 return retval;
599}
600
601/*
602 * Returns waiting task that should be serviced first or NULL if none exists
603 */
604static struct ext_wait_queue *wq_get_first_waiter(
605 struct mqueue_inode_info *info, int sr)
606{
607 struct list_head *ptr;
608
609 ptr = info->e_wait_q[sr].list.prev;
610 if (ptr == &info->e_wait_q[sr].list)
611 return NULL;
612 return list_entry(ptr, struct ext_wait_queue, list);
613}
614
615
616static inline void set_cookie(struct sk_buff *skb, char code)
617{
618 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
619}
620
621/*
622 * The next function is only to split too long sys_mq_timedsend
623 */
624static void __do_notify(struct mqueue_inode_info *info)
625{
626 /* notification
627 * invoked when there is registered process and there isn't process
628 * waiting synchronously for message AND state of queue changed from
629 * empty to not empty. Here we are sure that no one is waiting
630 * synchronously. */
631 if (info->notify_owner &&
632 info->attr.mq_curmsgs == 1) {
633 struct siginfo sig_i;
634 switch (info->notify.sigev_notify) {
635 case SIGEV_NONE:
636 break;
637 case SIGEV_SIGNAL:
638 /* sends signal */
639
640 sig_i.si_signo = info->notify.sigev_signo;
641 sig_i.si_errno = 0;
642 sig_i.si_code = SI_MESGQ;
643 sig_i.si_value = info->notify.sigev_value;
644 /* map current pid/uid into info->owner's namespaces */
645 rcu_read_lock();
646 sig_i.si_pid = task_tgid_nr_ns(current,
647 ns_of_pid(info->notify_owner));
648 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
649 rcu_read_unlock();
650
651 kill_pid_info(info->notify.sigev_signo,
652 &sig_i, info->notify_owner);
653 break;
654 case SIGEV_THREAD:
655 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
656 netlink_sendskb(info->notify_sock, info->notify_cookie);
657 break;
658 }
659 /* after notification unregisters process */
660 put_pid(info->notify_owner);
661 put_user_ns(info->notify_user_ns);
662 info->notify_owner = NULL;
663 info->notify_user_ns = NULL;
664 }
665 wake_up(&info->wait_q);
666}
667
668static int prepare_timeout(const struct timespec __user *u_abs_timeout,
669 ktime_t *expires, struct timespec *ts)
670{
671 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
672 return -EFAULT;
673 if (!timespec_valid(ts))
674 return -EINVAL;
675
676 *expires = timespec_to_ktime(*ts);
677 return 0;
678}
679
680static void remove_notification(struct mqueue_inode_info *info)
681{
682 if (info->notify_owner != NULL &&
683 info->notify.sigev_notify == SIGEV_THREAD) {
684 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
685 netlink_sendskb(info->notify_sock, info->notify_cookie);
686 }
687 put_pid(info->notify_owner);
688 put_user_ns(info->notify_user_ns);
689 info->notify_owner = NULL;
690 info->notify_user_ns = NULL;
691}
692
693static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
694{
695 int mq_treesize;
696 unsigned long total_size;
697
698 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
699 return -EINVAL;
700 if (capable(CAP_SYS_RESOURCE)) {
701 if (attr->mq_maxmsg > HARD_MSGMAX ||
702 attr->mq_msgsize > HARD_MSGSIZEMAX)
703 return -EINVAL;
704 } else {
705 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
706 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
707 return -EINVAL;
708 }
709 /* check for overflow */
710 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
711 return -EOVERFLOW;
712 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
713 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
714 sizeof(struct posix_msg_tree_node);
715 total_size = attr->mq_maxmsg * attr->mq_msgsize;
716 if (total_size + mq_treesize < total_size)
717 return -EOVERFLOW;
718 return 0;
719}
720
721/*
722 * Invoked when creating a new queue via sys_mq_open
723 */
724static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
725 struct dentry *dentry, int oflag, umode_t mode,
726 struct mq_attr *attr)
727{
728 const struct cred *cred = current_cred();
729 struct file *result;
730 int ret;
731
732 if (attr) {
733 ret = mq_attr_ok(ipc_ns, attr);
734 if (ret)
735 goto out;
736 /* store for use during create */
737 dentry->d_fsdata = attr;
738 } else {
739 struct mq_attr def_attr;
740
741 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
742 ipc_ns->mq_msg_default);
743 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
744 ipc_ns->mq_msgsize_default);
745 ret = mq_attr_ok(ipc_ns, &def_attr);
746 if (ret)
747 goto out;
748 }
749
750 mode &= ~current_umask();
751 ret = mnt_want_write(ipc_ns->mq_mnt);
752 if (ret)
753 goto out;
754 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
755 dentry->d_fsdata = NULL;
756 if (ret)
757 goto out_drop_write;
758
759 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
760 /*
761 * dentry_open() took a persistent mnt_want_write(),
762 * so we can now drop this one.
763 */
764 mnt_drop_write(ipc_ns->mq_mnt);
765 return result;
766
767out_drop_write:
768 mnt_drop_write(ipc_ns->mq_mnt);
769out:
770 dput(dentry);
771 mntput(ipc_ns->mq_mnt);
772 return ERR_PTR(ret);
773}
774
775/* Opens existing queue */
776static struct file *do_open(struct ipc_namespace *ipc_ns,
777 struct dentry *dentry, int oflag)
778{
779 int ret;
780 const struct cred *cred = current_cred();
781
782 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
783 MAY_READ | MAY_WRITE };
784
785 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
786 ret = -EINVAL;
787 goto err;
788 }
789
790 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
791 ret = -EACCES;
792 goto err;
793 }
794
795 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
796
797err:
798 dput(dentry);
799 mntput(ipc_ns->mq_mnt);
800 return ERR_PTR(ret);
801}
802
803SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
804 struct mq_attr __user *, u_attr)
805{
806 struct dentry *dentry;
807 struct file *filp;
808 char *name;
809 struct mq_attr attr;
810 int fd, error;
811 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
812
813 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
814 return -EFAULT;
815
816 audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
817
818 if (IS_ERR(name = getname(u_name)))
819 return PTR_ERR(name);
820
821 fd = get_unused_fd_flags(O_CLOEXEC);
822 if (fd < 0)
823 goto out_putname;
824
825 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
826 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
827 if (IS_ERR(dentry)) {
828 error = PTR_ERR(dentry);
829 goto out_putfd;
830 }
831 mntget(ipc_ns->mq_mnt);
832
833 if (oflag & O_CREAT) {
834 if (dentry->d_inode) { /* entry already exists */
835 audit_inode(name, dentry);
836 if (oflag & O_EXCL) {
837 error = -EEXIST;
838 goto out;
839 }
840 filp = do_open(ipc_ns, dentry, oflag);
841 } else {
842 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
843 dentry, oflag, mode,
844 u_attr ? &attr : NULL);
845 }
846 } else {
847 if (!dentry->d_inode) {
848 error = -ENOENT;
849 goto out;
850 }
851 audit_inode(name, dentry);
852 filp = do_open(ipc_ns, dentry, oflag);
853 }
854
855 if (IS_ERR(filp)) {
856 error = PTR_ERR(filp);
857 goto out_putfd;
858 }
859
860 fd_install(fd, filp);
861 goto out_upsem;
862
863out:
864 dput(dentry);
865 mntput(ipc_ns->mq_mnt);
866out_putfd:
867 put_unused_fd(fd);
868 fd = error;
869out_upsem:
870 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
871out_putname:
872 putname(name);
873 return fd;
874}
875
876SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
877{
878 int err;
879 char *name;
880 struct dentry *dentry;
881 struct inode *inode = NULL;
882 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
883
884 name = getname(u_name);
885 if (IS_ERR(name))
886 return PTR_ERR(name);
887
888 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
889 I_MUTEX_PARENT);
890 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
891 if (IS_ERR(dentry)) {
892 err = PTR_ERR(dentry);
893 goto out_unlock;
894 }
895
896 if (!dentry->d_inode) {
897 err = -ENOENT;
898 goto out_err;
899 }
900
901 inode = dentry->d_inode;
902 if (inode)
903 ihold(inode);
904 err = mnt_want_write(ipc_ns->mq_mnt);
905 if (err)
906 goto out_err;
907 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
908 mnt_drop_write(ipc_ns->mq_mnt);
909out_err:
910 dput(dentry);
911
912out_unlock:
913 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
914 putname(name);
915 if (inode)
916 iput(inode);
917
918 return err;
919}
920
921/* Pipelined send and receive functions.
922 *
923 * If a receiver finds no waiting message, then it registers itself in the
924 * list of waiting receivers. A sender checks that list before adding the new
925 * message into the message array. If there is a waiting receiver, then it
926 * bypasses the message array and directly hands the message over to the
927 * receiver.
928 * The receiver accepts the message and returns without grabbing the queue
929 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
930 * are necessary. The same algorithm is used for sysv semaphores, see
931 * ipc/sem.c for more details.
932 *
933 * The same algorithm is used for senders.
934 */
935
936/* pipelined_send() - send a message directly to the task waiting in
937 * sys_mq_timedreceive() (without inserting message into a queue).
938 */
939static inline void pipelined_send(struct mqueue_inode_info *info,
940 struct msg_msg *message,
941 struct ext_wait_queue *receiver)
942{
943 receiver->msg = message;
944 list_del(&receiver->list);
945 receiver->state = STATE_PENDING;
946 wake_up_process(receiver->task);
947 smp_wmb();
948 receiver->state = STATE_READY;
949}
950
951/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
952 * gets its message and put to the queue (we have one free place for sure). */
953static inline void pipelined_receive(struct mqueue_inode_info *info)
954{
955 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
956
957 if (!sender) {
958 /* for poll */
959 wake_up_interruptible(&info->wait_q);
960 return;
961 }
962 if (msg_insert(sender->msg, info))
963 return;
964 list_del(&sender->list);
965 sender->state = STATE_PENDING;
966 wake_up_process(sender->task);
967 smp_wmb();
968 sender->state = STATE_READY;
969}
970
971SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
972 size_t, msg_len, unsigned int, msg_prio,
973 const struct timespec __user *, u_abs_timeout)
974{
975 struct file *filp;
976 struct inode *inode;
977 struct ext_wait_queue wait;
978 struct ext_wait_queue *receiver;
979 struct msg_msg *msg_ptr;
980 struct mqueue_inode_info *info;
981 ktime_t expires, *timeout = NULL;
982 struct timespec ts;
983 struct posix_msg_tree_node *new_leaf = NULL;
984 int ret = 0;
985
986 if (u_abs_timeout) {
987 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
988 if (res)
989 return res;
990 timeout = &expires;
991 }
992
993 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
994 return -EINVAL;
995
996 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
997
998 filp = fget(mqdes);
999 if (unlikely(!filp)) {
1000 ret = -EBADF;
1001 goto out;
1002 }
1003
1004 inode = filp->f_path.dentry->d_inode;
1005 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1006 ret = -EBADF;
1007 goto out_fput;
1008 }
1009 info = MQUEUE_I(inode);
1010 audit_inode(NULL, filp->f_path.dentry);
1011
1012 if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
1013 ret = -EBADF;
1014 goto out_fput;
1015 }
1016
1017 if (unlikely(msg_len > info->attr.mq_msgsize)) {
1018 ret = -EMSGSIZE;
1019 goto out_fput;
1020 }
1021
1022 /* First try to allocate memory, before doing anything with
1023 * existing queues. */
1024 msg_ptr = load_msg(u_msg_ptr, msg_len);
1025 if (IS_ERR(msg_ptr)) {
1026 ret = PTR_ERR(msg_ptr);
1027 goto out_fput;
1028 }
1029 msg_ptr->m_ts = msg_len;
1030 msg_ptr->m_type = msg_prio;
1031
1032 /*
1033 * msg_insert really wants us to have a valid, spare node struct so
1034 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1035 * fall back to that if necessary.
1036 */
1037 if (!info->node_cache)
1038 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1039
1040 spin_lock(&info->lock);
1041
1042 if (!info->node_cache && new_leaf) {
1043 /* Save our speculative allocation into the cache */
1044 rb_init_node(&new_leaf->rb_node);
1045 INIT_LIST_HEAD(&new_leaf->msg_list);
1046 info->node_cache = new_leaf;
1047 info->qsize += sizeof(*new_leaf);
1048 new_leaf = NULL;
1049 } else {
1050 kfree(new_leaf);
1051 }
1052
1053 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1054 if (filp->f_flags & O_NONBLOCK) {
1055 ret = -EAGAIN;
1056 } else {
1057 wait.task = current;
1058 wait.msg = (void *) msg_ptr;
1059 wait.state = STATE_NONE;
1060 ret = wq_sleep(info, SEND, timeout, &wait);
1061 /*
1062 * wq_sleep must be called with info->lock held, and
1063 * returns with the lock released
1064 */
1065 goto out_free;
1066 }
1067 } else {
1068 receiver = wq_get_first_waiter(info, RECV);
1069 if (receiver) {
1070 pipelined_send(info, msg_ptr, receiver);
1071 } else {
1072 /* adds message to the queue */
1073 ret = msg_insert(msg_ptr, info);
1074 if (ret)
1075 goto out_unlock;
1076 __do_notify(info);
1077 }
1078 inode->i_atime = inode->i_mtime = inode->i_ctime =
1079 CURRENT_TIME;
1080 }
1081out_unlock:
1082 spin_unlock(&info->lock);
1083out_free:
1084 if (ret)
1085 free_msg(msg_ptr);
1086out_fput:
1087 fput(filp);
1088out:
1089 return ret;
1090}
1091
1092SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1093 size_t, msg_len, unsigned int __user *, u_msg_prio,
1094 const struct timespec __user *, u_abs_timeout)
1095{
1096 ssize_t ret;
1097 struct msg_msg *msg_ptr;
1098 struct file *filp;
1099 struct inode *inode;
1100 struct mqueue_inode_info *info;
1101 struct ext_wait_queue wait;
1102 ktime_t expires, *timeout = NULL;
1103 struct timespec ts;
1104 struct posix_msg_tree_node *new_leaf = NULL;
1105
1106 if (u_abs_timeout) {
1107 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1108 if (res)
1109 return res;
1110 timeout = &expires;
1111 }
1112
1113 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1114
1115 filp = fget(mqdes);
1116 if (unlikely(!filp)) {
1117 ret = -EBADF;
1118 goto out;
1119 }
1120
1121 inode = filp->f_path.dentry->d_inode;
1122 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1123 ret = -EBADF;
1124 goto out_fput;
1125 }
1126 info = MQUEUE_I(inode);
1127 audit_inode(NULL, filp->f_path.dentry);
1128
1129 if (unlikely(!(filp->f_mode & FMODE_READ))) {
1130 ret = -EBADF;
1131 goto out_fput;
1132 }
1133
1134 /* checks if buffer is big enough */
1135 if (unlikely(msg_len < info->attr.mq_msgsize)) {
1136 ret = -EMSGSIZE;
1137 goto out_fput;
1138 }
1139
1140 /*
1141 * msg_insert really wants us to have a valid, spare node struct so
1142 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1143 * fall back to that if necessary.
1144 */
1145 if (!info->node_cache)
1146 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1147
1148 spin_lock(&info->lock);
1149
1150 if (!info->node_cache && new_leaf) {
1151 /* Save our speculative allocation into the cache */
1152 rb_init_node(&new_leaf->rb_node);
1153 INIT_LIST_HEAD(&new_leaf->msg_list);
1154 info->node_cache = new_leaf;
1155 info->qsize += sizeof(*new_leaf);
1156 } else {
1157 kfree(new_leaf);
1158 }
1159
1160 if (info->attr.mq_curmsgs == 0) {
1161 if (filp->f_flags & O_NONBLOCK) {
1162 spin_unlock(&info->lock);
1163 ret = -EAGAIN;
1164 } else {
1165 wait.task = current;
1166 wait.state = STATE_NONE;
1167 ret = wq_sleep(info, RECV, timeout, &wait);
1168 msg_ptr = wait.msg;
1169 }
1170 } else {
1171 msg_ptr = msg_get(info);
1172
1173 inode->i_atime = inode->i_mtime = inode->i_ctime =
1174 CURRENT_TIME;
1175
1176 /* There is now free space in queue. */
1177 pipelined_receive(info);
1178 spin_unlock(&info->lock);
1179 ret = 0;
1180 }
1181 if (ret == 0) {
1182 ret = msg_ptr->m_ts;
1183
1184 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1185 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1186 ret = -EFAULT;
1187 }
1188 free_msg(msg_ptr);
1189 }
1190out_fput:
1191 fput(filp);
1192out:
1193 return ret;
1194}
1195
1196/*
1197 * Notes: the case when user wants us to deregister (with NULL as pointer)
1198 * and he isn't currently owner of notification, will be silently discarded.
1199 * It isn't explicitly defined in the POSIX.
1200 */
1201SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1202 const struct sigevent __user *, u_notification)
1203{
1204 int ret;
1205 struct file *filp;
1206 struct sock *sock;
1207 struct inode *inode;
1208 struct sigevent notification;
1209 struct mqueue_inode_info *info;
1210 struct sk_buff *nc;
1211
1212 if (u_notification) {
1213 if (copy_from_user(¬ification, u_notification,
1214 sizeof(struct sigevent)))
1215 return -EFAULT;
1216 }
1217
1218 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL);
1219
1220 nc = NULL;
1221 sock = NULL;
1222 if (u_notification != NULL) {
1223 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1224 notification.sigev_notify != SIGEV_SIGNAL &&
1225 notification.sigev_notify != SIGEV_THREAD))
1226 return -EINVAL;
1227 if (notification.sigev_notify == SIGEV_SIGNAL &&
1228 !valid_signal(notification.sigev_signo)) {
1229 return -EINVAL;
1230 }
1231 if (notification.sigev_notify == SIGEV_THREAD) {
1232 long timeo;
1233
1234 /* create the notify skb */
1235 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1236 if (!nc) {
1237 ret = -ENOMEM;
1238 goto out;
1239 }
1240 if (copy_from_user(nc->data,
1241 notification.sigev_value.sival_ptr,
1242 NOTIFY_COOKIE_LEN)) {
1243 ret = -EFAULT;
1244 goto out;
1245 }
1246
1247 /* TODO: add a header? */
1248 skb_put(nc, NOTIFY_COOKIE_LEN);
1249 /* and attach it to the socket */
1250retry:
1251 filp = fget(notification.sigev_signo);
1252 if (!filp) {
1253 ret = -EBADF;
1254 goto out;
1255 }
1256 sock = netlink_getsockbyfilp(filp);
1257 fput(filp);
1258 if (IS_ERR(sock)) {
1259 ret = PTR_ERR(sock);
1260 sock = NULL;
1261 goto out;
1262 }
1263
1264 timeo = MAX_SCHEDULE_TIMEOUT;
1265 ret = netlink_attachskb(sock, nc, &timeo, NULL);
1266 if (ret == 1)
1267 goto retry;
1268 if (ret) {
1269 sock = NULL;
1270 nc = NULL;
1271 goto out;
1272 }
1273 }
1274 }
1275
1276 filp = fget(mqdes);
1277 if (!filp) {
1278 ret = -EBADF;
1279 goto out;
1280 }
1281
1282 inode = filp->f_path.dentry->d_inode;
1283 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1284 ret = -EBADF;
1285 goto out_fput;
1286 }
1287 info = MQUEUE_I(inode);
1288
1289 ret = 0;
1290 spin_lock(&info->lock);
1291 if (u_notification == NULL) {
1292 if (info->notify_owner == task_tgid(current)) {
1293 remove_notification(info);
1294 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1295 }
1296 } else if (info->notify_owner != NULL) {
1297 ret = -EBUSY;
1298 } else {
1299 switch (notification.sigev_notify) {
1300 case SIGEV_NONE:
1301 info->notify.sigev_notify = SIGEV_NONE;
1302 break;
1303 case SIGEV_THREAD:
1304 info->notify_sock = sock;
1305 info->notify_cookie = nc;
1306 sock = NULL;
1307 nc = NULL;
1308 info->notify.sigev_notify = SIGEV_THREAD;
1309 break;
1310 case SIGEV_SIGNAL:
1311 info->notify.sigev_signo = notification.sigev_signo;
1312 info->notify.sigev_value = notification.sigev_value;
1313 info->notify.sigev_notify = SIGEV_SIGNAL;
1314 break;
1315 }
1316
1317 info->notify_owner = get_pid(task_tgid(current));
1318 info->notify_user_ns = get_user_ns(current_user_ns());
1319 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1320 }
1321 spin_unlock(&info->lock);
1322out_fput:
1323 fput(filp);
1324out:
1325 if (sock) {
1326 netlink_detachskb(sock, nc);
1327 } else if (nc) {
1328 dev_kfree_skb(nc);
1329 }
1330 return ret;
1331}
1332
1333SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1334 const struct mq_attr __user *, u_mqstat,
1335 struct mq_attr __user *, u_omqstat)
1336{
1337 int ret;
1338 struct mq_attr mqstat, omqstat;
1339 struct file *filp;
1340 struct inode *inode;
1341 struct mqueue_inode_info *info;
1342
1343 if (u_mqstat != NULL) {
1344 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1345 return -EFAULT;
1346 if (mqstat.mq_flags & (~O_NONBLOCK))
1347 return -EINVAL;
1348 }
1349
1350 filp = fget(mqdes);
1351 if (!filp) {
1352 ret = -EBADF;
1353 goto out;
1354 }
1355
1356 inode = filp->f_path.dentry->d_inode;
1357 if (unlikely(filp->f_op != &mqueue_file_operations)) {
1358 ret = -EBADF;
1359 goto out_fput;
1360 }
1361 info = MQUEUE_I(inode);
1362
1363 spin_lock(&info->lock);
1364
1365 omqstat = info->attr;
1366 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1367 if (u_mqstat) {
1368 audit_mq_getsetattr(mqdes, &mqstat);
1369 spin_lock(&filp->f_lock);
1370 if (mqstat.mq_flags & O_NONBLOCK)
1371 filp->f_flags |= O_NONBLOCK;
1372 else
1373 filp->f_flags &= ~O_NONBLOCK;
1374 spin_unlock(&filp->f_lock);
1375
1376 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1377 }
1378
1379 spin_unlock(&info->lock);
1380
1381 ret = 0;
1382 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1383 sizeof(struct mq_attr)))
1384 ret = -EFAULT;
1385
1386out_fput:
1387 fput(filp);
1388out:
1389 return ret;
1390}
1391
1392static const struct inode_operations mqueue_dir_inode_operations = {
1393 .lookup = simple_lookup,
1394 .create = mqueue_create,
1395 .unlink = mqueue_unlink,
1396};
1397
1398static const struct file_operations mqueue_file_operations = {
1399 .flush = mqueue_flush_file,
1400 .poll = mqueue_poll_file,
1401 .read = mqueue_read_file,
1402 .llseek = default_llseek,
1403};
1404
1405static const struct super_operations mqueue_super_ops = {
1406 .alloc_inode = mqueue_alloc_inode,
1407 .destroy_inode = mqueue_destroy_inode,
1408 .evict_inode = mqueue_evict_inode,
1409 .statfs = simple_statfs,
1410};
1411
1412static struct file_system_type mqueue_fs_type = {
1413 .name = "mqueue",
1414 .mount = mqueue_mount,
1415 .kill_sb = kill_litter_super,
1416};
1417
1418int mq_init_ns(struct ipc_namespace *ns)
1419{
1420 ns->mq_queues_count = 0;
1421 ns->mq_queues_max = DFLT_QUEUESMAX;
1422 ns->mq_msg_max = DFLT_MSGMAX;
1423 ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1424 ns->mq_msg_default = DFLT_MSG;
1425 ns->mq_msgsize_default = DFLT_MSGSIZE;
1426
1427 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1428 if (IS_ERR(ns->mq_mnt)) {
1429 int err = PTR_ERR(ns->mq_mnt);
1430 ns->mq_mnt = NULL;
1431 return err;
1432 }
1433 return 0;
1434}
1435
1436void mq_clear_sbinfo(struct ipc_namespace *ns)
1437{
1438 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1439}
1440
1441void mq_put_mnt(struct ipc_namespace *ns)
1442{
1443 kern_unmount(ns->mq_mnt);
1444}
1445
1446static int __init init_mqueue_fs(void)
1447{
1448 int error;
1449
1450 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1451 sizeof(struct mqueue_inode_info), 0,
1452 SLAB_HWCACHE_ALIGN, init_once);
1453 if (mqueue_inode_cachep == NULL)
1454 return -ENOMEM;
1455
1456 /* ignore failures - they are not fatal */
1457 mq_sysctl_table = mq_register_sysctl_table();
1458
1459 error = register_filesystem(&mqueue_fs_type);
1460 if (error)
1461 goto out_sysctl;
1462
1463 spin_lock_init(&mq_lock);
1464
1465 error = mq_init_ns(&init_ipc_ns);
1466 if (error)
1467 goto out_filesystem;
1468
1469 return 0;
1470
1471out_filesystem:
1472 unregister_filesystem(&mqueue_fs_type);
1473out_sysctl:
1474 if (mq_sysctl_table)
1475 unregister_sysctl_table(mq_sysctl_table);
1476 kmem_cache_destroy(mqueue_inode_cachep);
1477 return error;
1478}
1479
1480__initcall(init_mqueue_fs);
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
53struct posix_msg_tree_node {
54 struct rb_node rb_node;
55 struct list_head msg_list;
56 int priority;
57};
58
59struct 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
66struct 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
88static const struct inode_operations mqueue_dir_inode_operations;
89static const struct file_operations mqueue_file_operations;
90static const struct super_operations mqueue_super_ops;
91static void remove_notification(struct mqueue_inode_info *info);
92
93static struct kmem_cache *mqueue_inode_cachep;
94
95static struct ctl_table_header *mq_sysctl_table;
96
97static 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 */
105static 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
110static 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 */
121static 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);
151insert_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
158static 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
164try_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
216static 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;
303out_inode:
304 iput(inode);
305err:
306 return ERR_PTR(ret);
307}
308
309static 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
329static 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
346static 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
353static 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
363static 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
369static void mqueue_destroy_inode(struct inode *inode)
370{
371 call_rcu(&inode->i_rcu, mqueue_i_callback);
372}
373
374static 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
422static 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;
460out_unlock:
461 spin_unlock(&mq_lock);
462 if (ipc_ns)
463 put_ipc_ns(ipc_ns);
464 return error;
465}
466
467static 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*/
485static 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
513static 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
525static 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 */
544static 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 */
565static 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);
602out_unlock:
603 spin_unlock(&info->lock);
604out:
605 return retval;
606}
607
608/*
609 * Returns waiting task that should be serviced first or NULL if none exists
610 */
611static 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
623static 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 */
631static 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
675static 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
687static 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
700static 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 */
731static 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 */
765static 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
778SYSCALL_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);
844out:
845 path_put(&path);
846out_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);
854out_putname:
855 putname(name);
856 return fd;
857}
858
859SYSCALL_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
893out_unlock:
894 mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
895 if (inode)
896 iput(inode);
897 mnt_drop_write(mnt);
898out_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 */
922static 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). */
936static 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
954SYSCALL_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 }
1063out_unlock:
1064 spin_unlock(&info->lock);
1065out_free:
1066 if (ret)
1067 free_msg(msg_ptr);
1068out_fput:
1069 fdput(f);
1070out:
1071 return ret;
1072}
1073
1074SYSCALL_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 }
1171out_fput:
1172 fdput(f);
1173out:
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 */
1182SYSCALL_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(¬ification, u_notification,
1195 sizeof(struct sigevent)))
1196 return -EFAULT;
1197 }
1198
1199 audit_mq_notify(mqdes, u_notification ? ¬ification : 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 */
1231retry:
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);
1303out_fput:
1304 fdput(f);
1305out:
1306 if (sock)
1307 netlink_detachskb(sock, nc);
1308 else if (nc)
1309 dev_kfree_skb(nc);
1310
1311 return ret;
1312}
1313
1314SYSCALL_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
1367out_fput:
1368 fdput(f);
1369out:
1370 return ret;
1371}
1372
1373static const struct inode_operations mqueue_dir_inode_operations = {
1374 .lookup = simple_lookup,
1375 .create = mqueue_create,
1376 .unlink = mqueue_unlink,
1377};
1378
1379static 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
1386static 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
1393static 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
1400int 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
1418void mq_clear_sbinfo(struct ipc_namespace *ns)
1419{
1420 ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1421}
1422
1423void mq_put_mnt(struct ipc_namespace *ns)
1424{
1425 kern_unmount(ns->mq_mnt);
1426}
1427
1428static 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
1453out_filesystem:
1454 unregister_filesystem(&mqueue_fs_type);
1455out_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
1462device_initcall(init_mqueue_fs);