sanitize AUDIT_MQ_SENDRECV
[linux-2.6.git] / ipc / mqueue.c
1 /*
2  * POSIX message queues filesystem for Linux.
3  *
4  * Copyright (C) 2003,2004  Krzysztof Benedyczak    (golbi@mat.uni.torun.pl)
5  *                          Michal Wronski          (michal.wronski@gmail.com)
6  *
7  * Spinlocks:               Mohamed Abbas           (abbas.mohamed@intel.com)
8  * Lockless receive & send, fd based notify:
9  *                          Manfred Spraul          (manfred@colorfullife.com)
10  *
11  * Audit:                   George Wilson           (ltcgcw@us.ibm.com)
12  *
13  * This file is released under the GPL.
14  */
15
16 #include <linux/capability.h>
17 #include <linux/init.h>
18 #include <linux/pagemap.h>
19 #include <linux/file.h>
20 #include <linux/mount.h>
21 #include <linux/namei.h>
22 #include <linux/sysctl.h>
23 #include <linux/poll.h>
24 #include <linux/mqueue.h>
25 #include <linux/msg.h>
26 #include <linux/skbuff.h>
27 #include <linux/netlink.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/signal.h>
31 #include <linux/mutex.h>
32 #include <linux/nsproxy.h>
33 #include <linux/pid.h>
34
35 #include <net/sock.h>
36 #include "util.h"
37
38 #define MQUEUE_MAGIC    0x19800202
39 #define DIRENT_SIZE     20
40 #define FILENT_SIZE     80
41
42 #define SEND            0
43 #define RECV            1
44
45 #define STATE_NONE      0
46 #define STATE_PENDING   1
47 #define STATE_READY     2
48
49 /* default values */
50 #define DFLT_QUEUESMAX  256     /* max number of message queues */
51 #define DFLT_MSGMAX     10      /* max number of messages in each queue */
52 #define HARD_MSGMAX     (131072/sizeof(void*))
53 #define DFLT_MSGSIZEMAX 8192    /* max message size */
54
55 /*
56  * Define the ranges various user-specified maximum values can
57  * be set to.
58  */
59 #define MIN_MSGMAX      1               /* min value for msg_max */
60 #define MAX_MSGMAX      HARD_MSGMAX     /* max value for msg_max */
61 #define MIN_MSGSIZEMAX  128             /* min value for msgsize_max */
62 #define MAX_MSGSIZEMAX  (8192*128)      /* max value for msgsize_max */
63
64 struct ext_wait_queue {         /* queue of sleeping tasks */
65         struct task_struct *task;
66         struct list_head list;
67         struct msg_msg *msg;    /* ptr of loaded message */
68         int state;              /* one of STATE_* values */
69 };
70
71 struct mqueue_inode_info {
72         spinlock_t lock;
73         struct inode vfs_inode;
74         wait_queue_head_t wait_q;
75
76         struct msg_msg **messages;
77         struct mq_attr attr;
78
79         struct sigevent notify;
80         struct pid* notify_owner;
81         struct user_struct *user;       /* user who created, for accounting */
82         struct sock *notify_sock;
83         struct sk_buff *notify_cookie;
84
85         /* for tasks waiting for free space and messages, respectively */
86         struct ext_wait_queue e_wait_q[2];
87
88         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
89 };
90
91 static const struct inode_operations mqueue_dir_inode_operations;
92 static const struct file_operations mqueue_file_operations;
93 static struct super_operations mqueue_super_ops;
94 static void remove_notification(struct mqueue_inode_info *info);
95
96 static spinlock_t mq_lock;
97 static struct kmem_cache *mqueue_inode_cachep;
98 static struct vfsmount *mqueue_mnt;
99
100 static unsigned int queues_count;
101 static unsigned int queues_max  = DFLT_QUEUESMAX;
102 static unsigned int msg_max     = DFLT_MSGMAX;
103 static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
104
105 static struct ctl_table_header * mq_sysctl_table;
106
107 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
108 {
109         return container_of(inode, struct mqueue_inode_info, vfs_inode);
110 }
111
112 static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
113                                                         struct mq_attr *attr)
114 {
115         struct user_struct *u = current_user();
116         struct inode *inode;
117
118         inode = new_inode(sb);
119         if (inode) {
120                 inode->i_mode = mode;
121                 inode->i_uid = current_fsuid();
122                 inode->i_gid = current_fsgid();
123                 inode->i_blocks = 0;
124                 inode->i_mtime = inode->i_ctime = inode->i_atime =
125                                 CURRENT_TIME;
126
127                 if (S_ISREG(mode)) {
128                         struct mqueue_inode_info *info;
129                         struct task_struct *p = current;
130                         unsigned long mq_bytes, mq_msg_tblsz;
131
132                         inode->i_fop = &mqueue_file_operations;
133                         inode->i_size = FILENT_SIZE;
134                         /* mqueue specific info */
135                         info = MQUEUE_I(inode);
136                         spin_lock_init(&info->lock);
137                         init_waitqueue_head(&info->wait_q);
138                         INIT_LIST_HEAD(&info->e_wait_q[0].list);
139                         INIT_LIST_HEAD(&info->e_wait_q[1].list);
140                         info->messages = NULL;
141                         info->notify_owner = NULL;
142                         info->qsize = 0;
143                         info->user = NULL;      /* set when all is ok */
144                         memset(&info->attr, 0, sizeof(info->attr));
145                         info->attr.mq_maxmsg = msg_max;
146                         info->attr.mq_msgsize = msgsize_max;
147                         if (attr) {
148                                 info->attr.mq_maxmsg = attr->mq_maxmsg;
149                                 info->attr.mq_msgsize = attr->mq_msgsize;
150                         }
151                         mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
152                         mq_bytes = (mq_msg_tblsz +
153                                 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
154
155                         spin_lock(&mq_lock);
156                         if (u->mq_bytes + mq_bytes < u->mq_bytes ||
157                             u->mq_bytes + mq_bytes >
158                             p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
159                                 spin_unlock(&mq_lock);
160                                 goto out_inode;
161                         }
162                         u->mq_bytes += mq_bytes;
163                         spin_unlock(&mq_lock);
164
165                         info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
166                         if (!info->messages) {
167                                 spin_lock(&mq_lock);
168                                 u->mq_bytes -= mq_bytes;
169                                 spin_unlock(&mq_lock);
170                                 goto out_inode;
171                         }
172                         /* all is ok */
173                         info->user = get_uid(u);
174                 } else if (S_ISDIR(mode)) {
175                         inc_nlink(inode);
176                         /* Some things misbehave if size == 0 on a directory */
177                         inode->i_size = 2 * DIRENT_SIZE;
178                         inode->i_op = &mqueue_dir_inode_operations;
179                         inode->i_fop = &simple_dir_operations;
180                 }
181         }
182         return inode;
183 out_inode:
184         make_bad_inode(inode);
185         iput(inode);
186         return NULL;
187 }
188
189 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
190 {
191         struct inode *inode;
192
193         sb->s_blocksize = PAGE_CACHE_SIZE;
194         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
195         sb->s_magic = MQUEUE_MAGIC;
196         sb->s_op = &mqueue_super_ops;
197
198         inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
199         if (!inode)
200                 return -ENOMEM;
201
202         sb->s_root = d_alloc_root(inode);
203         if (!sb->s_root) {
204                 iput(inode);
205                 return -ENOMEM;
206         }
207
208         return 0;
209 }
210
211 static int mqueue_get_sb(struct file_system_type *fs_type,
212                          int flags, const char *dev_name,
213                          void *data, struct vfsmount *mnt)
214 {
215         return get_sb_single(fs_type, flags, data, mqueue_fill_super, mnt);
216 }
217
218 static void init_once(void *foo)
219 {
220         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
221
222         inode_init_once(&p->vfs_inode);
223 }
224
225 static struct inode *mqueue_alloc_inode(struct super_block *sb)
226 {
227         struct mqueue_inode_info *ei;
228
229         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
230         if (!ei)
231                 return NULL;
232         return &ei->vfs_inode;
233 }
234
235 static void mqueue_destroy_inode(struct inode *inode)
236 {
237         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
238 }
239
240 static void mqueue_delete_inode(struct inode *inode)
241 {
242         struct mqueue_inode_info *info;
243         struct user_struct *user;
244         unsigned long mq_bytes;
245         int i;
246
247         if (S_ISDIR(inode->i_mode)) {
248                 clear_inode(inode);
249                 return;
250         }
251         info = MQUEUE_I(inode);
252         spin_lock(&info->lock);
253         for (i = 0; i < info->attr.mq_curmsgs; i++)
254                 free_msg(info->messages[i]);
255         kfree(info->messages);
256         spin_unlock(&info->lock);
257
258         clear_inode(inode);
259
260         mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
261                    (info->attr.mq_maxmsg * info->attr.mq_msgsize));
262         user = info->user;
263         if (user) {
264                 spin_lock(&mq_lock);
265                 user->mq_bytes -= mq_bytes;
266                 queues_count--;
267                 spin_unlock(&mq_lock);
268                 free_uid(user);
269         }
270 }
271
272 static int mqueue_create(struct inode *dir, struct dentry *dentry,
273                                 int mode, struct nameidata *nd)
274 {
275         struct inode *inode;
276         struct mq_attr *attr = dentry->d_fsdata;
277         int error;
278
279         spin_lock(&mq_lock);
280         if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
281                 error = -ENOSPC;
282                 goto out_lock;
283         }
284         queues_count++;
285         spin_unlock(&mq_lock);
286
287         inode = mqueue_get_inode(dir->i_sb, mode, attr);
288         if (!inode) {
289                 error = -ENOMEM;
290                 spin_lock(&mq_lock);
291                 queues_count--;
292                 goto out_lock;
293         }
294
295         dir->i_size += DIRENT_SIZE;
296         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
297
298         d_instantiate(dentry, inode);
299         dget(dentry);
300         return 0;
301 out_lock:
302         spin_unlock(&mq_lock);
303         return error;
304 }
305
306 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
307 {
308         struct inode *inode = dentry->d_inode;
309
310         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
311         dir->i_size -= DIRENT_SIZE;
312         drop_nlink(inode);
313         dput(dentry);
314         return 0;
315 }
316
317 /*
318 *       This is routine for system read from queue file.
319 *       To avoid mess with doing here some sort of mq_receive we allow
320 *       to read only queue size & notification info (the only values
321 *       that are interesting from user point of view and aren't accessible
322 *       through std routines)
323 */
324 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
325                                 size_t count, loff_t *off)
326 {
327         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
328         char buffer[FILENT_SIZE];
329         ssize_t ret;
330
331         spin_lock(&info->lock);
332         snprintf(buffer, sizeof(buffer),
333                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
334                         info->qsize,
335                         info->notify_owner ? info->notify.sigev_notify : 0,
336                         (info->notify_owner &&
337                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
338                                 info->notify.sigev_signo : 0,
339                         pid_vnr(info->notify_owner));
340         spin_unlock(&info->lock);
341         buffer[sizeof(buffer)-1] = '\0';
342
343         ret = simple_read_from_buffer(u_data, count, off, buffer,
344                                 strlen(buffer));
345         if (ret <= 0)
346                 return ret;
347
348         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
349         return ret;
350 }
351
352 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
353 {
354         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
355
356         spin_lock(&info->lock);
357         if (task_tgid(current) == info->notify_owner)
358                 remove_notification(info);
359
360         spin_unlock(&info->lock);
361         return 0;
362 }
363
364 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
365 {
366         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
367         int retval = 0;
368
369         poll_wait(filp, &info->wait_q, poll_tab);
370
371         spin_lock(&info->lock);
372         if (info->attr.mq_curmsgs)
373                 retval = POLLIN | POLLRDNORM;
374
375         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
376                 retval |= POLLOUT | POLLWRNORM;
377         spin_unlock(&info->lock);
378
379         return retval;
380 }
381
382 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
383 static void wq_add(struct mqueue_inode_info *info, int sr,
384                         struct ext_wait_queue *ewp)
385 {
386         struct ext_wait_queue *walk;
387
388         ewp->task = current;
389
390         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
391                 if (walk->task->static_prio <= current->static_prio) {
392                         list_add_tail(&ewp->list, &walk->list);
393                         return;
394                 }
395         }
396         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
397 }
398
399 /*
400  * Puts current task to sleep. Caller must hold queue lock. After return
401  * lock isn't held.
402  * sr: SEND or RECV
403  */
404 static int wq_sleep(struct mqueue_inode_info *info, int sr,
405                         long timeout, struct ext_wait_queue *ewp)
406 {
407         int retval;
408         signed long time;
409
410         wq_add(info, sr, ewp);
411
412         for (;;) {
413                 set_current_state(TASK_INTERRUPTIBLE);
414
415                 spin_unlock(&info->lock);
416                 time = schedule_timeout(timeout);
417
418                 while (ewp->state == STATE_PENDING)
419                         cpu_relax();
420
421                 if (ewp->state == STATE_READY) {
422                         retval = 0;
423                         goto out;
424                 }
425                 spin_lock(&info->lock);
426                 if (ewp->state == STATE_READY) {
427                         retval = 0;
428                         goto out_unlock;
429                 }
430                 if (signal_pending(current)) {
431                         retval = -ERESTARTSYS;
432                         break;
433                 }
434                 if (time == 0) {
435                         retval = -ETIMEDOUT;
436                         break;
437                 }
438         }
439         list_del(&ewp->list);
440 out_unlock:
441         spin_unlock(&info->lock);
442 out:
443         return retval;
444 }
445
446 /*
447  * Returns waiting task that should be serviced first or NULL if none exists
448  */
449 static struct ext_wait_queue *wq_get_first_waiter(
450                 struct mqueue_inode_info *info, int sr)
451 {
452         struct list_head *ptr;
453
454         ptr = info->e_wait_q[sr].list.prev;
455         if (ptr == &info->e_wait_q[sr].list)
456                 return NULL;
457         return list_entry(ptr, struct ext_wait_queue, list);
458 }
459
460 /* Auxiliary functions to manipulate messages' list */
461 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
462 {
463         int k;
464
465         k = info->attr.mq_curmsgs - 1;
466         while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
467                 info->messages[k + 1] = info->messages[k];
468                 k--;
469         }
470         info->attr.mq_curmsgs++;
471         info->qsize += ptr->m_ts;
472         info->messages[k + 1] = ptr;
473 }
474
475 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
476 {
477         info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
478         return info->messages[info->attr.mq_curmsgs];
479 }
480
481 static inline void set_cookie(struct sk_buff *skb, char code)
482 {
483         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
484 }
485
486 /*
487  * The next function is only to split too long sys_mq_timedsend
488  */
489 static void __do_notify(struct mqueue_inode_info *info)
490 {
491         /* notification
492          * invoked when there is registered process and there isn't process
493          * waiting synchronously for message AND state of queue changed from
494          * empty to not empty. Here we are sure that no one is waiting
495          * synchronously. */
496         if (info->notify_owner &&
497             info->attr.mq_curmsgs == 1) {
498                 struct siginfo sig_i;
499                 switch (info->notify.sigev_notify) {
500                 case SIGEV_NONE:
501                         break;
502                 case SIGEV_SIGNAL:
503                         /* sends signal */
504
505                         sig_i.si_signo = info->notify.sigev_signo;
506                         sig_i.si_errno = 0;
507                         sig_i.si_code = SI_MESGQ;
508                         sig_i.si_value = info->notify.sigev_value;
509                         sig_i.si_pid = task_tgid_vnr(current);
510                         sig_i.si_uid = current_uid();
511
512                         kill_pid_info(info->notify.sigev_signo,
513                                       &sig_i, info->notify_owner);
514                         break;
515                 case SIGEV_THREAD:
516                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
517                         netlink_sendskb(info->notify_sock, info->notify_cookie);
518                         break;
519                 }
520                 /* after notification unregisters process */
521                 put_pid(info->notify_owner);
522                 info->notify_owner = NULL;
523         }
524         wake_up(&info->wait_q);
525 }
526
527 static long prepare_timeout(struct timespec *p)
528 {
529         struct timespec nowts;
530         long timeout;
531
532         if (p) {
533                 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
534                         || p->tv_nsec >= NSEC_PER_SEC))
535                         return -EINVAL;
536                 nowts = CURRENT_TIME;
537                 /* first subtract as jiffies can't be too big */
538                 p->tv_sec -= nowts.tv_sec;
539                 if (p->tv_nsec < nowts.tv_nsec) {
540                         p->tv_nsec += NSEC_PER_SEC;
541                         p->tv_sec--;
542                 }
543                 p->tv_nsec -= nowts.tv_nsec;
544                 if (p->tv_sec < 0)
545                         return 0;
546
547                 timeout = timespec_to_jiffies(p) + 1;
548         } else
549                 return MAX_SCHEDULE_TIMEOUT;
550
551         return timeout;
552 }
553
554 static void remove_notification(struct mqueue_inode_info *info)
555 {
556         if (info->notify_owner != NULL &&
557             info->notify.sigev_notify == SIGEV_THREAD) {
558                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
559                 netlink_sendskb(info->notify_sock, info->notify_cookie);
560         }
561         put_pid(info->notify_owner);
562         info->notify_owner = NULL;
563 }
564
565 static int mq_attr_ok(struct mq_attr *attr)
566 {
567         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
568                 return 0;
569         if (capable(CAP_SYS_RESOURCE)) {
570                 if (attr->mq_maxmsg > HARD_MSGMAX)
571                         return 0;
572         } else {
573                 if (attr->mq_maxmsg > msg_max ||
574                                 attr->mq_msgsize > msgsize_max)
575                         return 0;
576         }
577         /* check for overflow */
578         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
579                 return 0;
580         if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
581             (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
582             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
583                 return 0;
584         return 1;
585 }
586
587 /*
588  * Invoked when creating a new queue via sys_mq_open
589  */
590 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
591                         int oflag, mode_t mode, struct mq_attr __user *u_attr)
592 {
593         const struct cred *cred = current_cred();
594         struct mq_attr attr;
595         struct file *result;
596         int ret;
597
598         if (u_attr) {
599                 ret = -EFAULT;
600                 if (copy_from_user(&attr, u_attr, sizeof(attr)))
601                         goto out;
602                 ret = -EINVAL;
603                 if (!mq_attr_ok(&attr))
604                         goto out;
605                 /* store for use during create */
606                 dentry->d_fsdata = &attr;
607         }
608
609         mode &= ~current->fs->umask;
610         ret = mnt_want_write(mqueue_mnt);
611         if (ret)
612                 goto out;
613         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
614         dentry->d_fsdata = NULL;
615         if (ret)
616                 goto out_drop_write;
617
618         result = dentry_open(dentry, mqueue_mnt, oflag, cred);
619         /*
620          * dentry_open() took a persistent mnt_want_write(),
621          * so we can now drop this one.
622          */
623         mnt_drop_write(mqueue_mnt);
624         return result;
625
626 out_drop_write:
627         mnt_drop_write(mqueue_mnt);
628 out:
629         dput(dentry);
630         mntput(mqueue_mnt);
631         return ERR_PTR(ret);
632 }
633
634 /* Opens existing queue */
635 static struct file *do_open(struct dentry *dentry, int oflag)
636 {
637         const struct cred *cred = current_cred();
638
639         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
640                                                   MAY_READ | MAY_WRITE };
641
642         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
643                 dput(dentry);
644                 mntput(mqueue_mnt);
645                 return ERR_PTR(-EINVAL);
646         }
647
648         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
649                 dput(dentry);
650                 mntput(mqueue_mnt);
651                 return ERR_PTR(-EACCES);
652         }
653
654         return dentry_open(dentry, mqueue_mnt, oflag, cred);
655 }
656
657 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
658                                 struct mq_attr __user *u_attr)
659 {
660         struct dentry *dentry;
661         struct file *filp;
662         char *name;
663         int fd, error;
664
665         error = audit_mq_open(oflag, mode, u_attr);
666         if (error != 0)
667                 return error;
668
669         if (IS_ERR(name = getname(u_name)))
670                 return PTR_ERR(name);
671
672         fd = get_unused_fd_flags(O_CLOEXEC);
673         if (fd < 0)
674                 goto out_putname;
675
676         mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
677         dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
678         if (IS_ERR(dentry)) {
679                 error = PTR_ERR(dentry);
680                 goto out_err;
681         }
682         mntget(mqueue_mnt);
683
684         if (oflag & O_CREAT) {
685                 if (dentry->d_inode) {  /* entry already exists */
686                         audit_inode(name, dentry);
687                         error = -EEXIST;
688                         if (oflag & O_EXCL)
689                                 goto out;
690                         filp = do_open(dentry, oflag);
691                 } else {
692                         filp = do_create(mqueue_mnt->mnt_root, dentry,
693                                                 oflag, mode, u_attr);
694                 }
695         } else {
696                 error = -ENOENT;
697                 if (!dentry->d_inode)
698                         goto out;
699                 audit_inode(name, dentry);
700                 filp = do_open(dentry, oflag);
701         }
702
703         if (IS_ERR(filp)) {
704                 error = PTR_ERR(filp);
705                 goto out_putfd;
706         }
707
708         fd_install(fd, filp);
709         goto out_upsem;
710
711 out:
712         dput(dentry);
713         mntput(mqueue_mnt);
714 out_putfd:
715         put_unused_fd(fd);
716 out_err:
717         fd = error;
718 out_upsem:
719         mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
720 out_putname:
721         putname(name);
722         return fd;
723 }
724
725 asmlinkage long sys_mq_unlink(const char __user *u_name)
726 {
727         int err;
728         char *name;
729         struct dentry *dentry;
730         struct inode *inode = NULL;
731
732         name = getname(u_name);
733         if (IS_ERR(name))
734                 return PTR_ERR(name);
735
736         mutex_lock_nested(&mqueue_mnt->mnt_root->d_inode->i_mutex,
737                         I_MUTEX_PARENT);
738         dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
739         if (IS_ERR(dentry)) {
740                 err = PTR_ERR(dentry);
741                 goto out_unlock;
742         }
743
744         if (!dentry->d_inode) {
745                 err = -ENOENT;
746                 goto out_err;
747         }
748
749         inode = dentry->d_inode;
750         if (inode)
751                 atomic_inc(&inode->i_count);
752         err = mnt_want_write(mqueue_mnt);
753         if (err)
754                 goto out_err;
755         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
756         mnt_drop_write(mqueue_mnt);
757 out_err:
758         dput(dentry);
759
760 out_unlock:
761         mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
762         putname(name);
763         if (inode)
764                 iput(inode);
765
766         return err;
767 }
768
769 /* Pipelined send and receive functions.
770  *
771  * If a receiver finds no waiting message, then it registers itself in the
772  * list of waiting receivers. A sender checks that list before adding the new
773  * message into the message array. If there is a waiting receiver, then it
774  * bypasses the message array and directly hands the message over to the
775  * receiver.
776  * The receiver accepts the message and returns without grabbing the queue
777  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
778  * are necessary. The same algorithm is used for sysv semaphores, see
779  * ipc/sem.c for more details.
780  *
781  * The same algorithm is used for senders.
782  */
783
784 /* pipelined_send() - send a message directly to the task waiting in
785  * sys_mq_timedreceive() (without inserting message into a queue).
786  */
787 static inline void pipelined_send(struct mqueue_inode_info *info,
788                                   struct msg_msg *message,
789                                   struct ext_wait_queue *receiver)
790 {
791         receiver->msg = message;
792         list_del(&receiver->list);
793         receiver->state = STATE_PENDING;
794         wake_up_process(receiver->task);
795         smp_wmb();
796         receiver->state = STATE_READY;
797 }
798
799 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
800  * gets its message and put to the queue (we have one free place for sure). */
801 static inline void pipelined_receive(struct mqueue_inode_info *info)
802 {
803         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
804
805         if (!sender) {
806                 /* for poll */
807                 wake_up_interruptible(&info->wait_q);
808                 return;
809         }
810         msg_insert(sender->msg, info);
811         list_del(&sender->list);
812         sender->state = STATE_PENDING;
813         wake_up_process(sender->task);
814         smp_wmb();
815         sender->state = STATE_READY;
816 }
817
818 asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
819         size_t msg_len, unsigned int msg_prio,
820         const struct timespec __user *u_abs_timeout)
821 {
822         struct file *filp;
823         struct inode *inode;
824         struct ext_wait_queue wait;
825         struct ext_wait_queue *receiver;
826         struct msg_msg *msg_ptr;
827         struct mqueue_inode_info *info;
828         struct timespec ts, *p = NULL;
829         long timeout;
830         int ret;
831
832         if (u_abs_timeout) {
833                 if (copy_from_user(&ts, u_abs_timeout, 
834                                         sizeof(struct timespec)))
835                         return -EFAULT;
836                 p = &ts;
837         }
838
839         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
840                 return -EINVAL;
841
842         audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
843         timeout = prepare_timeout(p);
844
845         ret = -EBADF;
846         filp = fget(mqdes);
847         if (unlikely(!filp))
848                 goto out;
849
850         inode = filp->f_path.dentry->d_inode;
851         if (unlikely(filp->f_op != &mqueue_file_operations))
852                 goto out_fput;
853         info = MQUEUE_I(inode);
854         audit_inode(NULL, filp->f_path.dentry);
855
856         if (unlikely(!(filp->f_mode & FMODE_WRITE)))
857                 goto out_fput;
858
859         if (unlikely(msg_len > info->attr.mq_msgsize)) {
860                 ret = -EMSGSIZE;
861                 goto out_fput;
862         }
863
864         /* First try to allocate memory, before doing anything with
865          * existing queues. */
866         msg_ptr = load_msg(u_msg_ptr, msg_len);
867         if (IS_ERR(msg_ptr)) {
868                 ret = PTR_ERR(msg_ptr);
869                 goto out_fput;
870         }
871         msg_ptr->m_ts = msg_len;
872         msg_ptr->m_type = msg_prio;
873
874         spin_lock(&info->lock);
875
876         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
877                 if (filp->f_flags & O_NONBLOCK) {
878                         spin_unlock(&info->lock);
879                         ret = -EAGAIN;
880                 } else if (unlikely(timeout < 0)) {
881                         spin_unlock(&info->lock);
882                         ret = timeout;
883                 } else {
884                         wait.task = current;
885                         wait.msg = (void *) msg_ptr;
886                         wait.state = STATE_NONE;
887                         ret = wq_sleep(info, SEND, timeout, &wait);
888                 }
889                 if (ret < 0)
890                         free_msg(msg_ptr);
891         } else {
892                 receiver = wq_get_first_waiter(info, RECV);
893                 if (receiver) {
894                         pipelined_send(info, msg_ptr, receiver);
895                 } else {
896                         /* adds message to the queue */
897                         msg_insert(msg_ptr, info);
898                         __do_notify(info);
899                 }
900                 inode->i_atime = inode->i_mtime = inode->i_ctime =
901                                 CURRENT_TIME;
902                 spin_unlock(&info->lock);
903                 ret = 0;
904         }
905 out_fput:
906         fput(filp);
907 out:
908         return ret;
909 }
910
911 asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
912         size_t msg_len, unsigned int __user *u_msg_prio,
913         const struct timespec __user *u_abs_timeout)
914 {
915         long timeout;
916         ssize_t ret;
917         struct msg_msg *msg_ptr;
918         struct file *filp;
919         struct inode *inode;
920         struct mqueue_inode_info *info;
921         struct ext_wait_queue wait;
922         struct timespec ts, *p = NULL;
923
924         if (u_abs_timeout) {
925                 if (copy_from_user(&ts, u_abs_timeout, 
926                                         sizeof(struct timespec)))
927                         return -EFAULT;
928                 p = &ts;
929         }
930
931         audit_mq_sendrecv(mqdes, msg_len, 0, p);
932         timeout = prepare_timeout(p);
933
934         ret = -EBADF;
935         filp = fget(mqdes);
936         if (unlikely(!filp))
937                 goto out;
938
939         inode = filp->f_path.dentry->d_inode;
940         if (unlikely(filp->f_op != &mqueue_file_operations))
941                 goto out_fput;
942         info = MQUEUE_I(inode);
943         audit_inode(NULL, filp->f_path.dentry);
944
945         if (unlikely(!(filp->f_mode & FMODE_READ)))
946                 goto out_fput;
947
948         /* checks if buffer is big enough */
949         if (unlikely(msg_len < info->attr.mq_msgsize)) {
950                 ret = -EMSGSIZE;
951                 goto out_fput;
952         }
953
954         spin_lock(&info->lock);
955         if (info->attr.mq_curmsgs == 0) {
956                 if (filp->f_flags & O_NONBLOCK) {
957                         spin_unlock(&info->lock);
958                         ret = -EAGAIN;
959                         msg_ptr = NULL;
960                 } else if (unlikely(timeout < 0)) {
961                         spin_unlock(&info->lock);
962                         ret = timeout;
963                         msg_ptr = NULL;
964                 } else {
965                         wait.task = current;
966                         wait.state = STATE_NONE;
967                         ret = wq_sleep(info, RECV, timeout, &wait);
968                         msg_ptr = wait.msg;
969                 }
970         } else {
971                 msg_ptr = msg_get(info);
972
973                 inode->i_atime = inode->i_mtime = inode->i_ctime =
974                                 CURRENT_TIME;
975
976                 /* There is now free space in queue. */
977                 pipelined_receive(info);
978                 spin_unlock(&info->lock);
979                 ret = 0;
980         }
981         if (ret == 0) {
982                 ret = msg_ptr->m_ts;
983
984                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
985                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
986                         ret = -EFAULT;
987                 }
988                 free_msg(msg_ptr);
989         }
990 out_fput:
991         fput(filp);
992 out:
993         return ret;
994 }
995
996 /*
997  * Notes: the case when user wants us to deregister (with NULL as pointer)
998  * and he isn't currently owner of notification, will be silently discarded.
999  * It isn't explicitly defined in the POSIX.
1000  */
1001 asmlinkage long sys_mq_notify(mqd_t mqdes,
1002                                 const struct sigevent __user *u_notification)
1003 {
1004         int ret;
1005         struct file *filp;
1006         struct sock *sock;
1007         struct inode *inode;
1008         struct sigevent notification;
1009         struct mqueue_inode_info *info;
1010         struct sk_buff *nc;
1011
1012         if (u_notification) {
1013                 if (copy_from_user(&notification, u_notification,
1014                                         sizeof(struct sigevent)))
1015                         return -EFAULT;
1016         }
1017
1018         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1019
1020         nc = NULL;
1021         sock = NULL;
1022         if (u_notification != NULL) {
1023                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1024                              notification.sigev_notify != SIGEV_SIGNAL &&
1025                              notification.sigev_notify != SIGEV_THREAD))
1026                         return -EINVAL;
1027                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1028                         !valid_signal(notification.sigev_signo)) {
1029                         return -EINVAL;
1030                 }
1031                 if (notification.sigev_notify == SIGEV_THREAD) {
1032                         long timeo;
1033
1034                         /* create the notify skb */
1035                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1036                         ret = -ENOMEM;
1037                         if (!nc)
1038                                 goto out;
1039                         ret = -EFAULT;
1040                         if (copy_from_user(nc->data,
1041                                         notification.sigev_value.sival_ptr,
1042                                         NOTIFY_COOKIE_LEN)) {
1043                                 goto out;
1044                         }
1045
1046                         /* TODO: add a header? */
1047                         skb_put(nc, NOTIFY_COOKIE_LEN);
1048                         /* and attach it to the socket */
1049 retry:
1050                         filp = fget(notification.sigev_signo);
1051                         ret = -EBADF;
1052                         if (!filp)
1053                                 goto out;
1054                         sock = netlink_getsockbyfilp(filp);
1055                         fput(filp);
1056                         if (IS_ERR(sock)) {
1057                                 ret = PTR_ERR(sock);
1058                                 sock = NULL;
1059                                 goto out;
1060                         }
1061
1062                         timeo = MAX_SCHEDULE_TIMEOUT;
1063                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1064                         if (ret == 1)
1065                                 goto retry;
1066                         if (ret) {
1067                                 sock = NULL;
1068                                 nc = NULL;
1069                                 goto out;
1070                         }
1071                 }
1072         }
1073
1074         ret = -EBADF;
1075         filp = fget(mqdes);
1076         if (!filp)
1077                 goto out;
1078
1079         inode = filp->f_path.dentry->d_inode;
1080         if (unlikely(filp->f_op != &mqueue_file_operations))
1081                 goto out_fput;
1082         info = MQUEUE_I(inode);
1083
1084         ret = 0;
1085         spin_lock(&info->lock);
1086         if (u_notification == NULL) {
1087                 if (info->notify_owner == task_tgid(current)) {
1088                         remove_notification(info);
1089                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1090                 }
1091         } else if (info->notify_owner != NULL) {
1092                 ret = -EBUSY;
1093         } else {
1094                 switch (notification.sigev_notify) {
1095                 case SIGEV_NONE:
1096                         info->notify.sigev_notify = SIGEV_NONE;
1097                         break;
1098                 case SIGEV_THREAD:
1099                         info->notify_sock = sock;
1100                         info->notify_cookie = nc;
1101                         sock = NULL;
1102                         nc = NULL;
1103                         info->notify.sigev_notify = SIGEV_THREAD;
1104                         break;
1105                 case SIGEV_SIGNAL:
1106                         info->notify.sigev_signo = notification.sigev_signo;
1107                         info->notify.sigev_value = notification.sigev_value;
1108                         info->notify.sigev_notify = SIGEV_SIGNAL;
1109                         break;
1110                 }
1111
1112                 info->notify_owner = get_pid(task_tgid(current));
1113                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1114         }
1115         spin_unlock(&info->lock);
1116 out_fput:
1117         fput(filp);
1118 out:
1119         if (sock) {
1120                 netlink_detachskb(sock, nc);
1121         } else if (nc) {
1122                 dev_kfree_skb(nc);
1123         }
1124         return ret;
1125 }
1126
1127 asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
1128                         const struct mq_attr __user *u_mqstat,
1129                         struct mq_attr __user *u_omqstat)
1130 {
1131         int ret;
1132         struct mq_attr mqstat, omqstat;
1133         struct file *filp;
1134         struct inode *inode;
1135         struct mqueue_inode_info *info;
1136
1137         if (u_mqstat != NULL) {
1138                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1139                         return -EFAULT;
1140                 if (mqstat.mq_flags & (~O_NONBLOCK))
1141                         return -EINVAL;
1142         }
1143
1144         ret = -EBADF;
1145         filp = fget(mqdes);
1146         if (!filp)
1147                 goto out;
1148
1149         inode = filp->f_path.dentry->d_inode;
1150         if (unlikely(filp->f_op != &mqueue_file_operations))
1151                 goto out_fput;
1152         info = MQUEUE_I(inode);
1153
1154         spin_lock(&info->lock);
1155
1156         omqstat = info->attr;
1157         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1158         if (u_mqstat) {
1159                 audit_mq_getsetattr(mqdes, &mqstat);
1160                 if (mqstat.mq_flags & O_NONBLOCK)
1161                         filp->f_flags |= O_NONBLOCK;
1162                 else
1163                         filp->f_flags &= ~O_NONBLOCK;
1164
1165                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1166         }
1167
1168         spin_unlock(&info->lock);
1169
1170         ret = 0;
1171         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1172                                                 sizeof(struct mq_attr)))
1173                 ret = -EFAULT;
1174
1175 out_fput:
1176         fput(filp);
1177 out:
1178         return ret;
1179 }
1180
1181 static const struct inode_operations mqueue_dir_inode_operations = {
1182         .lookup = simple_lookup,
1183         .create = mqueue_create,
1184         .unlink = mqueue_unlink,
1185 };
1186
1187 static const struct file_operations mqueue_file_operations = {
1188         .flush = mqueue_flush_file,
1189         .poll = mqueue_poll_file,
1190         .read = mqueue_read_file,
1191 };
1192
1193 static struct super_operations mqueue_super_ops = {
1194         .alloc_inode = mqueue_alloc_inode,
1195         .destroy_inode = mqueue_destroy_inode,
1196         .statfs = simple_statfs,
1197         .delete_inode = mqueue_delete_inode,
1198         .drop_inode = generic_delete_inode,
1199 };
1200
1201 static struct file_system_type mqueue_fs_type = {
1202         .name = "mqueue",
1203         .get_sb = mqueue_get_sb,
1204         .kill_sb = kill_litter_super,
1205 };
1206
1207 static int msg_max_limit_min = MIN_MSGMAX;
1208 static int msg_max_limit_max = MAX_MSGMAX;
1209
1210 static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
1211 static int msg_maxsize_limit_max = MAX_MSGSIZEMAX;
1212
1213 static ctl_table mq_sysctls[] = {
1214         {
1215                 .procname       = "queues_max",
1216                 .data           = &queues_max,
1217                 .maxlen         = sizeof(int),
1218                 .mode           = 0644,
1219                 .proc_handler   = &proc_dointvec,
1220         },
1221         {
1222                 .procname       = "msg_max",
1223                 .data           = &msg_max,
1224                 .maxlen         = sizeof(int),
1225                 .mode           = 0644,
1226                 .proc_handler   = &proc_dointvec_minmax,
1227                 .extra1         = &msg_max_limit_min,
1228                 .extra2         = &msg_max_limit_max,
1229         },
1230         {
1231                 .procname       = "msgsize_max",
1232                 .data           = &msgsize_max,
1233                 .maxlen         = sizeof(int),
1234                 .mode           = 0644,
1235                 .proc_handler   = &proc_dointvec_minmax,
1236                 .extra1         = &msg_maxsize_limit_min,
1237                 .extra2         = &msg_maxsize_limit_max,
1238         },
1239         { .ctl_name = 0 }
1240 };
1241
1242 static ctl_table mq_sysctl_dir[] = {
1243         {
1244                 .procname       = "mqueue",
1245                 .mode           = 0555,
1246                 .child          = mq_sysctls,
1247         },
1248         { .ctl_name = 0 }
1249 };
1250
1251 static ctl_table mq_sysctl_root[] = {
1252         {
1253                 .ctl_name       = CTL_FS,
1254                 .procname       = "fs",
1255                 .mode           = 0555,
1256                 .child          = mq_sysctl_dir,
1257         },
1258         { .ctl_name = 0 }
1259 };
1260
1261 static int __init init_mqueue_fs(void)
1262 {
1263         int error;
1264
1265         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1266                                 sizeof(struct mqueue_inode_info), 0,
1267                                 SLAB_HWCACHE_ALIGN, init_once);
1268         if (mqueue_inode_cachep == NULL)
1269                 return -ENOMEM;
1270
1271         /* ignore failues - they are not fatal */
1272         mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
1273
1274         error = register_filesystem(&mqueue_fs_type);
1275         if (error)
1276                 goto out_sysctl;
1277
1278         if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
1279                 error = PTR_ERR(mqueue_mnt);
1280                 goto out_filesystem;
1281         }
1282
1283         /* internal initialization - not common for vfs */
1284         queues_count = 0;
1285         spin_lock_init(&mq_lock);
1286
1287         return 0;
1288
1289 out_filesystem:
1290         unregister_filesystem(&mqueue_fs_type);
1291 out_sysctl:
1292         if (mq_sysctl_table)
1293                 unregister_sysctl_table(mq_sysctl_table);
1294         kmem_cache_destroy(mqueue_inode_cachep);
1295         return error;
1296 }
1297
1298 __initcall(init_mqueue_fs);