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