Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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 #include <linux/ipc_namespace.h>
35
36 #include <net/sock.h>
37 #include "util.h"
38
39 #define MQUEUE_MAGIC    0x19800202
40 #define DIRENT_SIZE     20
41 #define FILENT_SIZE     80
42
43 #define SEND            0
44 #define RECV            1
45
46 #define STATE_NONE      0
47 #define STATE_PENDING   1
48 #define STATE_READY     2
49
50 struct ext_wait_queue {         /* queue of sleeping tasks */
51         struct task_struct *task;
52         struct list_head list;
53         struct msg_msg *msg;    /* ptr of loaded message */
54         int state;              /* one of STATE_* values */
55 };
56
57 struct mqueue_inode_info {
58         spinlock_t lock;
59         struct inode vfs_inode;
60         wait_queue_head_t wait_q;
61
62         struct msg_msg **messages;
63         struct mq_attr attr;
64
65         struct sigevent notify;
66         struct pid* notify_owner;
67         struct user_struct *user;       /* user who created, for accounting */
68         struct sock *notify_sock;
69         struct sk_buff *notify_cookie;
70
71         /* for tasks waiting for free space and messages, respectively */
72         struct ext_wait_queue e_wait_q[2];
73
74         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
75 };
76
77 static const struct inode_operations mqueue_dir_inode_operations;
78 static const struct file_operations mqueue_file_operations;
79 static const struct super_operations mqueue_super_ops;
80 static void remove_notification(struct mqueue_inode_info *info);
81
82 static struct kmem_cache *mqueue_inode_cachep;
83
84 static struct ctl_table_header * mq_sysctl_table;
85
86 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
87 {
88         return container_of(inode, struct mqueue_inode_info, vfs_inode);
89 }
90
91 /*
92  * This routine should be called with the mq_lock held.
93  */
94 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
95 {
96         return get_ipc_ns(inode->i_sb->s_fs_info);
97 }
98
99 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
100 {
101         struct ipc_namespace *ns;
102
103         spin_lock(&mq_lock);
104         ns = __get_ns_from_inode(inode);
105         spin_unlock(&mq_lock);
106         return ns;
107 }
108
109 static struct inode *mqueue_get_inode(struct super_block *sb,
110                 struct ipc_namespace *ipc_ns, int mode,
111                 struct mq_attr *attr)
112 {
113         struct user_struct *u = current_user();
114         struct inode *inode;
115
116         inode = new_inode(sb);
117         if (inode) {
118                 inode->i_mode = mode;
119                 inode->i_uid = current_fsuid();
120                 inode->i_gid = current_fsgid();
121                 inode->i_mtime = inode->i_ctime = inode->i_atime =
122                                 CURRENT_TIME;
123
124                 if (S_ISREG(mode)) {
125                         struct mqueue_inode_info *info;
126                         struct task_struct *p = current;
127                         unsigned long mq_bytes, mq_msg_tblsz;
128
129                         inode->i_fop = &mqueue_file_operations;
130                         inode->i_size = FILENT_SIZE;
131                         /* mqueue specific info */
132                         info = MQUEUE_I(inode);
133                         spin_lock_init(&info->lock);
134                         init_waitqueue_head(&info->wait_q);
135                         INIT_LIST_HEAD(&info->e_wait_q[0].list);
136                         INIT_LIST_HEAD(&info->e_wait_q[1].list);
137                         info->notify_owner = NULL;
138                         info->qsize = 0;
139                         info->user = NULL;      /* set when all is ok */
140                         memset(&info->attr, 0, sizeof(info->attr));
141                         info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
142                         info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
143                         if (attr) {
144                                 info->attr.mq_maxmsg = attr->mq_maxmsg;
145                                 info->attr.mq_msgsize = attr->mq_msgsize;
146                         }
147                         mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
148                         info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
149                         if (!info->messages)
150                                 goto out_inode;
151
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                             task_rlimit(p, RLIMIT_MSGQUEUE)) {
159                                 spin_unlock(&mq_lock);
160                                 kfree(info->messages);
161                                 goto out_inode;
162                         }
163                         u->mq_bytes += mq_bytes;
164                         spin_unlock(&mq_lock);
165
166                         /* all is ok */
167                         info->user = get_uid(u);
168                 } else if (S_ISDIR(mode)) {
169                         inc_nlink(inode);
170                         /* Some things misbehave if size == 0 on a directory */
171                         inode->i_size = 2 * DIRENT_SIZE;
172                         inode->i_op = &mqueue_dir_inode_operations;
173                         inode->i_fop = &simple_dir_operations;
174                 }
175         }
176         return inode;
177 out_inode:
178         make_bad_inode(inode);
179         iput(inode);
180         return NULL;
181 }
182
183 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
184 {
185         struct inode *inode;
186         struct ipc_namespace *ns = data;
187         int error;
188
189         sb->s_blocksize = PAGE_CACHE_SIZE;
190         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
191         sb->s_magic = MQUEUE_MAGIC;
192         sb->s_op = &mqueue_super_ops;
193
194         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
195                                 NULL);
196         if (!inode) {
197                 error = -ENOMEM;
198                 goto out;
199         }
200
201         sb->s_root = d_alloc_root(inode);
202         if (!sb->s_root) {
203                 iput(inode);
204                 error = -ENOMEM;
205                 goto out;
206         }
207         error = 0;
208
209 out:
210         return error;
211 }
212
213 static int mqueue_get_sb(struct file_system_type *fs_type,
214                          int flags, const char *dev_name,
215                          void *data, struct vfsmount *mnt)
216 {
217         if (!(flags & MS_KERNMOUNT))
218                 data = current->nsproxy->ipc_ns;
219         return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);
220 }
221
222 static void init_once(void *foo)
223 {
224         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
225
226         inode_init_once(&p->vfs_inode);
227 }
228
229 static struct inode *mqueue_alloc_inode(struct super_block *sb)
230 {
231         struct mqueue_inode_info *ei;
232
233         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
234         if (!ei)
235                 return NULL;
236         return &ei->vfs_inode;
237 }
238
239 static void mqueue_destroy_inode(struct inode *inode)
240 {
241         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
242 }
243
244 static void mqueue_delete_inode(struct inode *inode)
245 {
246         struct mqueue_inode_info *info;
247         struct user_struct *user;
248         unsigned long mq_bytes;
249         int i;
250         struct ipc_namespace *ipc_ns;
251
252         if (S_ISDIR(inode->i_mode)) {
253                 clear_inode(inode);
254                 return;
255         }
256         ipc_ns = get_ns_from_inode(inode);
257         info = MQUEUE_I(inode);
258         spin_lock(&info->lock);
259         for (i = 0; i < info->attr.mq_curmsgs; i++)
260                 free_msg(info->messages[i]);
261         kfree(info->messages);
262         spin_unlock(&info->lock);
263
264         clear_inode(inode);
265
266         /* Total amount of bytes accounted for the mqueue */
267         mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
268             + info->attr.mq_msgsize);
269         user = info->user;
270         if (user) {
271                 spin_lock(&mq_lock);
272                 user->mq_bytes -= mq_bytes;
273                 /*
274                  * get_ns_from_inode() ensures that the
275                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
276                  * to which we now hold a reference, or it is NULL.
277                  * We can't put it here under mq_lock, though.
278                  */
279                 if (ipc_ns)
280                         ipc_ns->mq_queues_count--;
281                 spin_unlock(&mq_lock);
282                 free_uid(user);
283         }
284         if (ipc_ns)
285                 put_ipc_ns(ipc_ns);
286 }
287
288 static int mqueue_create(struct inode *dir, struct dentry *dentry,
289                                 int mode, struct nameidata *nd)
290 {
291         struct inode *inode;
292         struct mq_attr *attr = dentry->d_fsdata;
293         int error;
294         struct ipc_namespace *ipc_ns;
295
296         spin_lock(&mq_lock);
297         ipc_ns = __get_ns_from_inode(dir);
298         if (!ipc_ns) {
299                 error = -EACCES;
300                 goto out_unlock;
301         }
302         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
303                         !capable(CAP_SYS_RESOURCE)) {
304                 error = -ENOSPC;
305                 goto out_unlock;
306         }
307         ipc_ns->mq_queues_count++;
308         spin_unlock(&mq_lock);
309
310         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
311         if (!inode) {
312                 error = -ENOMEM;
313                 spin_lock(&mq_lock);
314                 ipc_ns->mq_queues_count--;
315                 goto out_unlock;
316         }
317
318         put_ipc_ns(ipc_ns);
319         dir->i_size += DIRENT_SIZE;
320         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
321
322         d_instantiate(dentry, inode);
323         dget(dentry);
324         return 0;
325 out_unlock:
326         spin_unlock(&mq_lock);
327         if (ipc_ns)
328                 put_ipc_ns(ipc_ns);
329         return error;
330 }
331
332 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
333 {
334         struct inode *inode = dentry->d_inode;
335
336         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
337         dir->i_size -= DIRENT_SIZE;
338         drop_nlink(inode);
339         dput(dentry);
340         return 0;
341 }
342
343 /*
344 *       This is routine for system read from queue file.
345 *       To avoid mess with doing here some sort of mq_receive we allow
346 *       to read only queue size & notification info (the only values
347 *       that are interesting from user point of view and aren't accessible
348 *       through std routines)
349 */
350 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
351                                 size_t count, loff_t *off)
352 {
353         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
354         char buffer[FILENT_SIZE];
355         ssize_t ret;
356
357         spin_lock(&info->lock);
358         snprintf(buffer, sizeof(buffer),
359                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
360                         info->qsize,
361                         info->notify_owner ? info->notify.sigev_notify : 0,
362                         (info->notify_owner &&
363                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
364                                 info->notify.sigev_signo : 0,
365                         pid_vnr(info->notify_owner));
366         spin_unlock(&info->lock);
367         buffer[sizeof(buffer)-1] = '\0';
368
369         ret = simple_read_from_buffer(u_data, count, off, buffer,
370                                 strlen(buffer));
371         if (ret <= 0)
372                 return ret;
373
374         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
375         return ret;
376 }
377
378 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
379 {
380         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
381
382         spin_lock(&info->lock);
383         if (task_tgid(current) == info->notify_owner)
384                 remove_notification(info);
385
386         spin_unlock(&info->lock);
387         return 0;
388 }
389
390 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
391 {
392         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
393         int retval = 0;
394
395         poll_wait(filp, &info->wait_q, poll_tab);
396
397         spin_lock(&info->lock);
398         if (info->attr.mq_curmsgs)
399                 retval = POLLIN | POLLRDNORM;
400
401         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
402                 retval |= POLLOUT | POLLWRNORM;
403         spin_unlock(&info->lock);
404
405         return retval;
406 }
407
408 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
409 static void wq_add(struct mqueue_inode_info *info, int sr,
410                         struct ext_wait_queue *ewp)
411 {
412         struct ext_wait_queue *walk;
413
414         ewp->task = current;
415
416         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
417                 if (walk->task->static_prio <= current->static_prio) {
418                         list_add_tail(&ewp->list, &walk->list);
419                         return;
420                 }
421         }
422         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
423 }
424
425 /*
426  * Puts current task to sleep. Caller must hold queue lock. After return
427  * lock isn't held.
428  * sr: SEND or RECV
429  */
430 static int wq_sleep(struct mqueue_inode_info *info, int sr,
431                         long timeout, struct ext_wait_queue *ewp)
432 {
433         int retval;
434         signed long time;
435
436         wq_add(info, sr, ewp);
437
438         for (;;) {
439                 set_current_state(TASK_INTERRUPTIBLE);
440
441                 spin_unlock(&info->lock);
442                 time = schedule_timeout(timeout);
443
444                 while (ewp->state == STATE_PENDING)
445                         cpu_relax();
446
447                 if (ewp->state == STATE_READY) {
448                         retval = 0;
449                         goto out;
450                 }
451                 spin_lock(&info->lock);
452                 if (ewp->state == STATE_READY) {
453                         retval = 0;
454                         goto out_unlock;
455                 }
456                 if (signal_pending(current)) {
457                         retval = -ERESTARTSYS;
458                         break;
459                 }
460                 if (time == 0) {
461                         retval = -ETIMEDOUT;
462                         break;
463                 }
464         }
465         list_del(&ewp->list);
466 out_unlock:
467         spin_unlock(&info->lock);
468 out:
469         return retval;
470 }
471
472 /*
473  * Returns waiting task that should be serviced first or NULL if none exists
474  */
475 static struct ext_wait_queue *wq_get_first_waiter(
476                 struct mqueue_inode_info *info, int sr)
477 {
478         struct list_head *ptr;
479
480         ptr = info->e_wait_q[sr].list.prev;
481         if (ptr == &info->e_wait_q[sr].list)
482                 return NULL;
483         return list_entry(ptr, struct ext_wait_queue, list);
484 }
485
486 /* Auxiliary functions to manipulate messages' list */
487 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
488 {
489         int k;
490
491         k = info->attr.mq_curmsgs - 1;
492         while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
493                 info->messages[k + 1] = info->messages[k];
494                 k--;
495         }
496         info->attr.mq_curmsgs++;
497         info->qsize += ptr->m_ts;
498         info->messages[k + 1] = ptr;
499 }
500
501 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
502 {
503         info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
504         return info->messages[info->attr.mq_curmsgs];
505 }
506
507 static inline void set_cookie(struct sk_buff *skb, char code)
508 {
509         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
510 }
511
512 /*
513  * The next function is only to split too long sys_mq_timedsend
514  */
515 static void __do_notify(struct mqueue_inode_info *info)
516 {
517         /* notification
518          * invoked when there is registered process and there isn't process
519          * waiting synchronously for message AND state of queue changed from
520          * empty to not empty. Here we are sure that no one is waiting
521          * synchronously. */
522         if (info->notify_owner &&
523             info->attr.mq_curmsgs == 1) {
524                 struct siginfo sig_i;
525                 switch (info->notify.sigev_notify) {
526                 case SIGEV_NONE:
527                         break;
528                 case SIGEV_SIGNAL:
529                         /* sends signal */
530
531                         sig_i.si_signo = info->notify.sigev_signo;
532                         sig_i.si_errno = 0;
533                         sig_i.si_code = SI_MESGQ;
534                         sig_i.si_value = info->notify.sigev_value;
535                         sig_i.si_pid = task_tgid_nr_ns(current,
536                                                 ns_of_pid(info->notify_owner));
537                         sig_i.si_uid = current_uid();
538
539                         kill_pid_info(info->notify.sigev_signo,
540                                       &sig_i, info->notify_owner);
541                         break;
542                 case SIGEV_THREAD:
543                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
544                         netlink_sendskb(info->notify_sock, info->notify_cookie);
545                         break;
546                 }
547                 /* after notification unregisters process */
548                 put_pid(info->notify_owner);
549                 info->notify_owner = NULL;
550         }
551         wake_up(&info->wait_q);
552 }
553
554 static long prepare_timeout(struct timespec *p)
555 {
556         struct timespec nowts;
557         long timeout;
558
559         if (p) {
560                 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
561                         || p->tv_nsec >= NSEC_PER_SEC))
562                         return -EINVAL;
563                 nowts = CURRENT_TIME;
564                 /* first subtract as jiffies can't be too big */
565                 p->tv_sec -= nowts.tv_sec;
566                 if (p->tv_nsec < nowts.tv_nsec) {
567                         p->tv_nsec += NSEC_PER_SEC;
568                         p->tv_sec--;
569                 }
570                 p->tv_nsec -= nowts.tv_nsec;
571                 if (p->tv_sec < 0)
572                         return 0;
573
574                 timeout = timespec_to_jiffies(p) + 1;
575         } else
576                 return MAX_SCHEDULE_TIMEOUT;
577
578         return timeout;
579 }
580
581 static void remove_notification(struct mqueue_inode_info *info)
582 {
583         if (info->notify_owner != NULL &&
584             info->notify.sigev_notify == SIGEV_THREAD) {
585                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
586                 netlink_sendskb(info->notify_sock, info->notify_cookie);
587         }
588         put_pid(info->notify_owner);
589         info->notify_owner = NULL;
590 }
591
592 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
593 {
594         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
595                 return 0;
596         if (capable(CAP_SYS_RESOURCE)) {
597                 if (attr->mq_maxmsg > HARD_MSGMAX)
598                         return 0;
599         } else {
600                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
601                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
602                         return 0;
603         }
604         /* check for overflow */
605         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
606                 return 0;
607         if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
608             + sizeof (struct msg_msg *))) <
609             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
610                 return 0;
611         return 1;
612 }
613
614 /*
615  * Invoked when creating a new queue via sys_mq_open
616  */
617 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
618                         struct dentry *dentry, int oflag, mode_t mode,
619                         struct mq_attr *attr)
620 {
621         const struct cred *cred = current_cred();
622         struct file *result;
623         int ret;
624
625         if (attr) {
626                 if (!mq_attr_ok(ipc_ns, attr)) {
627                         ret = -EINVAL;
628                         goto out;
629                 }
630                 /* store for use during create */
631                 dentry->d_fsdata = attr;
632         }
633
634         mode &= ~current_umask();
635         ret = mnt_want_write(ipc_ns->mq_mnt);
636         if (ret)
637                 goto out;
638         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
639         dentry->d_fsdata = NULL;
640         if (ret)
641                 goto out_drop_write;
642
643         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
644         /*
645          * dentry_open() took a persistent mnt_want_write(),
646          * so we can now drop this one.
647          */
648         mnt_drop_write(ipc_ns->mq_mnt);
649         return result;
650
651 out_drop_write:
652         mnt_drop_write(ipc_ns->mq_mnt);
653 out:
654         dput(dentry);
655         mntput(ipc_ns->mq_mnt);
656         return ERR_PTR(ret);
657 }
658
659 /* Opens existing queue */
660 static struct file *do_open(struct ipc_namespace *ipc_ns,
661                                 struct dentry *dentry, int oflag)
662 {
663         int ret;
664         const struct cred *cred = current_cred();
665
666         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
667                                                   MAY_READ | MAY_WRITE };
668
669         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
670                 ret = -EINVAL;
671                 goto err;
672         }
673
674         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
675                 ret = -EACCES;
676                 goto err;
677         }
678
679         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
680
681 err:
682         dput(dentry);
683         mntput(ipc_ns->mq_mnt);
684         return ERR_PTR(ret);
685 }
686
687 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
688                 struct mq_attr __user *, u_attr)
689 {
690         struct dentry *dentry;
691         struct file *filp;
692         char *name;
693         struct mq_attr attr;
694         int fd, error;
695         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
696
697         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
698                 return -EFAULT;
699
700         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
701
702         if (IS_ERR(name = getname(u_name)))
703                 return PTR_ERR(name);
704
705         fd = get_unused_fd_flags(O_CLOEXEC);
706         if (fd < 0)
707                 goto out_putname;
708
709         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
710         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
711         if (IS_ERR(dentry)) {
712                 error = PTR_ERR(dentry);
713                 goto out_putfd;
714         }
715         mntget(ipc_ns->mq_mnt);
716
717         if (oflag & O_CREAT) {
718                 if (dentry->d_inode) {  /* entry already exists */
719                         audit_inode(name, dentry);
720                         if (oflag & O_EXCL) {
721                                 error = -EEXIST;
722                                 goto out;
723                         }
724                         filp = do_open(ipc_ns, dentry, oflag);
725                 } else {
726                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
727                                                 dentry, oflag, mode,
728                                                 u_attr ? &attr : NULL);
729                 }
730         } else {
731                 if (!dentry->d_inode) {
732                         error = -ENOENT;
733                         goto out;
734                 }
735                 audit_inode(name, dentry);
736                 filp = do_open(ipc_ns, dentry, oflag);
737         }
738
739         if (IS_ERR(filp)) {
740                 error = PTR_ERR(filp);
741                 goto out_putfd;
742         }
743
744         fd_install(fd, filp);
745         goto out_upsem;
746
747 out:
748         dput(dentry);
749         mntput(ipc_ns->mq_mnt);
750 out_putfd:
751         put_unused_fd(fd);
752         fd = error;
753 out_upsem:
754         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
755 out_putname:
756         putname(name);
757         return fd;
758 }
759
760 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
761 {
762         int err;
763         char *name;
764         struct dentry *dentry;
765         struct inode *inode = NULL;
766         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
767
768         name = getname(u_name);
769         if (IS_ERR(name))
770                 return PTR_ERR(name);
771
772         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
773                         I_MUTEX_PARENT);
774         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
775         if (IS_ERR(dentry)) {
776                 err = PTR_ERR(dentry);
777                 goto out_unlock;
778         }
779
780         if (!dentry->d_inode) {
781                 err = -ENOENT;
782                 goto out_err;
783         }
784
785         inode = dentry->d_inode;
786         if (inode)
787                 atomic_inc(&inode->i_count);
788         err = mnt_want_write(ipc_ns->mq_mnt);
789         if (err)
790                 goto out_err;
791         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
792         mnt_drop_write(ipc_ns->mq_mnt);
793 out_err:
794         dput(dentry);
795
796 out_unlock:
797         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
798         putname(name);
799         if (inode)
800                 iput(inode);
801
802         return err;
803 }
804
805 /* Pipelined send and receive functions.
806  *
807  * If a receiver finds no waiting message, then it registers itself in the
808  * list of waiting receivers. A sender checks that list before adding the new
809  * message into the message array. If there is a waiting receiver, then it
810  * bypasses the message array and directly hands the message over to the
811  * receiver.
812  * The receiver accepts the message and returns without grabbing the queue
813  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
814  * are necessary. The same algorithm is used for sysv semaphores, see
815  * ipc/sem.c for more details.
816  *
817  * The same algorithm is used for senders.
818  */
819
820 /* pipelined_send() - send a message directly to the task waiting in
821  * sys_mq_timedreceive() (without inserting message into a queue).
822  */
823 static inline void pipelined_send(struct mqueue_inode_info *info,
824                                   struct msg_msg *message,
825                                   struct ext_wait_queue *receiver)
826 {
827         receiver->msg = message;
828         list_del(&receiver->list);
829         receiver->state = STATE_PENDING;
830         wake_up_process(receiver->task);
831         smp_wmb();
832         receiver->state = STATE_READY;
833 }
834
835 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
836  * gets its message and put to the queue (we have one free place for sure). */
837 static inline void pipelined_receive(struct mqueue_inode_info *info)
838 {
839         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
840
841         if (!sender) {
842                 /* for poll */
843                 wake_up_interruptible(&info->wait_q);
844                 return;
845         }
846         msg_insert(sender->msg, info);
847         list_del(&sender->list);
848         sender->state = STATE_PENDING;
849         wake_up_process(sender->task);
850         smp_wmb();
851         sender->state = STATE_READY;
852 }
853
854 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
855                 size_t, msg_len, unsigned int, msg_prio,
856                 const struct timespec __user *, u_abs_timeout)
857 {
858         struct file *filp;
859         struct inode *inode;
860         struct ext_wait_queue wait;
861         struct ext_wait_queue *receiver;
862         struct msg_msg *msg_ptr;
863         struct mqueue_inode_info *info;
864         struct timespec ts, *p = NULL;
865         long timeout;
866         int ret;
867
868         if (u_abs_timeout) {
869                 if (copy_from_user(&ts, u_abs_timeout, 
870                                         sizeof(struct timespec)))
871                         return -EFAULT;
872                 p = &ts;
873         }
874
875         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
876                 return -EINVAL;
877
878         audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
879         timeout = prepare_timeout(p);
880
881         filp = fget(mqdes);
882         if (unlikely(!filp)) {
883                 ret = -EBADF;
884                 goto out;
885         }
886
887         inode = filp->f_path.dentry->d_inode;
888         if (unlikely(filp->f_op != &mqueue_file_operations)) {
889                 ret = -EBADF;
890                 goto out_fput;
891         }
892         info = MQUEUE_I(inode);
893         audit_inode(NULL, filp->f_path.dentry);
894
895         if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
896                 ret = -EBADF;
897                 goto out_fput;
898         }
899
900         if (unlikely(msg_len > info->attr.mq_msgsize)) {
901                 ret = -EMSGSIZE;
902                 goto out_fput;
903         }
904
905         /* First try to allocate memory, before doing anything with
906          * existing queues. */
907         msg_ptr = load_msg(u_msg_ptr, msg_len);
908         if (IS_ERR(msg_ptr)) {
909                 ret = PTR_ERR(msg_ptr);
910                 goto out_fput;
911         }
912         msg_ptr->m_ts = msg_len;
913         msg_ptr->m_type = msg_prio;
914
915         spin_lock(&info->lock);
916
917         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
918                 if (filp->f_flags & O_NONBLOCK) {
919                         spin_unlock(&info->lock);
920                         ret = -EAGAIN;
921                 } else if (unlikely(timeout < 0)) {
922                         spin_unlock(&info->lock);
923                         ret = timeout;
924                 } else {
925                         wait.task = current;
926                         wait.msg = (void *) msg_ptr;
927                         wait.state = STATE_NONE;
928                         ret = wq_sleep(info, SEND, timeout, &wait);
929                 }
930                 if (ret < 0)
931                         free_msg(msg_ptr);
932         } else {
933                 receiver = wq_get_first_waiter(info, RECV);
934                 if (receiver) {
935                         pipelined_send(info, msg_ptr, receiver);
936                 } else {
937                         /* adds message to the queue */
938                         msg_insert(msg_ptr, info);
939                         __do_notify(info);
940                 }
941                 inode->i_atime = inode->i_mtime = inode->i_ctime =
942                                 CURRENT_TIME;
943                 spin_unlock(&info->lock);
944                 ret = 0;
945         }
946 out_fput:
947         fput(filp);
948 out:
949         return ret;
950 }
951
952 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
953                 size_t, msg_len, unsigned int __user *, u_msg_prio,
954                 const struct timespec __user *, u_abs_timeout)
955 {
956         long timeout;
957         ssize_t ret;
958         struct msg_msg *msg_ptr;
959         struct file *filp;
960         struct inode *inode;
961         struct mqueue_inode_info *info;
962         struct ext_wait_queue wait;
963         struct timespec ts, *p = NULL;
964
965         if (u_abs_timeout) {
966                 if (copy_from_user(&ts, u_abs_timeout, 
967                                         sizeof(struct timespec)))
968                         return -EFAULT;
969                 p = &ts;
970         }
971
972         audit_mq_sendrecv(mqdes, msg_len, 0, p);
973         timeout = prepare_timeout(p);
974
975         filp = fget(mqdes);
976         if (unlikely(!filp)) {
977                 ret = -EBADF;
978                 goto out;
979         }
980
981         inode = filp->f_path.dentry->d_inode;
982         if (unlikely(filp->f_op != &mqueue_file_operations)) {
983                 ret = -EBADF;
984                 goto out_fput;
985         }
986         info = MQUEUE_I(inode);
987         audit_inode(NULL, filp->f_path.dentry);
988
989         if (unlikely(!(filp->f_mode & FMODE_READ))) {
990                 ret = -EBADF;
991                 goto out_fput;
992         }
993
994         /* checks if buffer is big enough */
995         if (unlikely(msg_len < info->attr.mq_msgsize)) {
996                 ret = -EMSGSIZE;
997                 goto out_fput;
998         }
999
1000         spin_lock(&info->lock);
1001         if (info->attr.mq_curmsgs == 0) {
1002                 if (filp->f_flags & O_NONBLOCK) {
1003                         spin_unlock(&info->lock);
1004                         ret = -EAGAIN;
1005                         msg_ptr = NULL;
1006                 } else if (unlikely(timeout < 0)) {
1007                         spin_unlock(&info->lock);
1008                         ret = timeout;
1009                         msg_ptr = NULL;
1010                 } else {
1011                         wait.task = current;
1012                         wait.state = STATE_NONE;
1013                         ret = wq_sleep(info, RECV, timeout, &wait);
1014                         msg_ptr = wait.msg;
1015                 }
1016         } else {
1017                 msg_ptr = msg_get(info);
1018
1019                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1020                                 CURRENT_TIME;
1021
1022                 /* There is now free space in queue. */
1023                 pipelined_receive(info);
1024                 spin_unlock(&info->lock);
1025                 ret = 0;
1026         }
1027         if (ret == 0) {
1028                 ret = msg_ptr->m_ts;
1029
1030                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1031                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1032                         ret = -EFAULT;
1033                 }
1034                 free_msg(msg_ptr);
1035         }
1036 out_fput:
1037         fput(filp);
1038 out:
1039         return ret;
1040 }
1041
1042 /*
1043  * Notes: the case when user wants us to deregister (with NULL as pointer)
1044  * and he isn't currently owner of notification, will be silently discarded.
1045  * It isn't explicitly defined in the POSIX.
1046  */
1047 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1048                 const struct sigevent __user *, u_notification)
1049 {
1050         int ret;
1051         struct file *filp;
1052         struct sock *sock;
1053         struct inode *inode;
1054         struct sigevent notification;
1055         struct mqueue_inode_info *info;
1056         struct sk_buff *nc;
1057
1058         if (u_notification) {
1059                 if (copy_from_user(&notification, u_notification,
1060                                         sizeof(struct sigevent)))
1061                         return -EFAULT;
1062         }
1063
1064         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1065
1066         nc = NULL;
1067         sock = NULL;
1068         if (u_notification != NULL) {
1069                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1070                              notification.sigev_notify != SIGEV_SIGNAL &&
1071                              notification.sigev_notify != SIGEV_THREAD))
1072                         return -EINVAL;
1073                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1074                         !valid_signal(notification.sigev_signo)) {
1075                         return -EINVAL;
1076                 }
1077                 if (notification.sigev_notify == SIGEV_THREAD) {
1078                         long timeo;
1079
1080                         /* create the notify skb */
1081                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1082                         if (!nc) {
1083                                 ret = -ENOMEM;
1084                                 goto out;
1085                         }
1086                         if (copy_from_user(nc->data,
1087                                         notification.sigev_value.sival_ptr,
1088                                         NOTIFY_COOKIE_LEN)) {
1089                                 ret = -EFAULT;
1090                                 goto out;
1091                         }
1092
1093                         /* TODO: add a header? */
1094                         skb_put(nc, NOTIFY_COOKIE_LEN);
1095                         /* and attach it to the socket */
1096 retry:
1097                         filp = fget(notification.sigev_signo);
1098                         if (!filp) {
1099                                 ret = -EBADF;
1100                                 goto out;
1101                         }
1102                         sock = netlink_getsockbyfilp(filp);
1103                         fput(filp);
1104                         if (IS_ERR(sock)) {
1105                                 ret = PTR_ERR(sock);
1106                                 sock = NULL;
1107                                 goto out;
1108                         }
1109
1110                         timeo = MAX_SCHEDULE_TIMEOUT;
1111                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1112                         if (ret == 1)
1113                                 goto retry;
1114                         if (ret) {
1115                                 sock = NULL;
1116                                 nc = NULL;
1117                                 goto out;
1118                         }
1119                 }
1120         }
1121
1122         filp = fget(mqdes);
1123         if (!filp) {
1124                 ret = -EBADF;
1125                 goto out;
1126         }
1127
1128         inode = filp->f_path.dentry->d_inode;
1129         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1130                 ret = -EBADF;
1131                 goto out_fput;
1132         }
1133         info = MQUEUE_I(inode);
1134
1135         ret = 0;
1136         spin_lock(&info->lock);
1137         if (u_notification == NULL) {
1138                 if (info->notify_owner == task_tgid(current)) {
1139                         remove_notification(info);
1140                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1141                 }
1142         } else if (info->notify_owner != NULL) {
1143                 ret = -EBUSY;
1144         } else {
1145                 switch (notification.sigev_notify) {
1146                 case SIGEV_NONE:
1147                         info->notify.sigev_notify = SIGEV_NONE;
1148                         break;
1149                 case SIGEV_THREAD:
1150                         info->notify_sock = sock;
1151                         info->notify_cookie = nc;
1152                         sock = NULL;
1153                         nc = NULL;
1154                         info->notify.sigev_notify = SIGEV_THREAD;
1155                         break;
1156                 case SIGEV_SIGNAL:
1157                         info->notify.sigev_signo = notification.sigev_signo;
1158                         info->notify.sigev_value = notification.sigev_value;
1159                         info->notify.sigev_notify = SIGEV_SIGNAL;
1160                         break;
1161                 }
1162
1163                 info->notify_owner = get_pid(task_tgid(current));
1164                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1165         }
1166         spin_unlock(&info->lock);
1167 out_fput:
1168         fput(filp);
1169 out:
1170         if (sock) {
1171                 netlink_detachskb(sock, nc);
1172         } else if (nc) {
1173                 dev_kfree_skb(nc);
1174         }
1175         return ret;
1176 }
1177
1178 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1179                 const struct mq_attr __user *, u_mqstat,
1180                 struct mq_attr __user *, u_omqstat)
1181 {
1182         int ret;
1183         struct mq_attr mqstat, omqstat;
1184         struct file *filp;
1185         struct inode *inode;
1186         struct mqueue_inode_info *info;
1187
1188         if (u_mqstat != NULL) {
1189                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1190                         return -EFAULT;
1191                 if (mqstat.mq_flags & (~O_NONBLOCK))
1192                         return -EINVAL;
1193         }
1194
1195         filp = fget(mqdes);
1196         if (!filp) {
1197                 ret = -EBADF;
1198                 goto out;
1199         }
1200
1201         inode = filp->f_path.dentry->d_inode;
1202         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1203                 ret = -EBADF;
1204                 goto out_fput;
1205         }
1206         info = MQUEUE_I(inode);
1207
1208         spin_lock(&info->lock);
1209
1210         omqstat = info->attr;
1211         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1212         if (u_mqstat) {
1213                 audit_mq_getsetattr(mqdes, &mqstat);
1214                 spin_lock(&filp->f_lock);
1215                 if (mqstat.mq_flags & O_NONBLOCK)
1216                         filp->f_flags |= O_NONBLOCK;
1217                 else
1218                         filp->f_flags &= ~O_NONBLOCK;
1219                 spin_unlock(&filp->f_lock);
1220
1221                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1222         }
1223
1224         spin_unlock(&info->lock);
1225
1226         ret = 0;
1227         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1228                                                 sizeof(struct mq_attr)))
1229                 ret = -EFAULT;
1230
1231 out_fput:
1232         fput(filp);
1233 out:
1234         return ret;
1235 }
1236
1237 static const struct inode_operations mqueue_dir_inode_operations = {
1238         .lookup = simple_lookup,
1239         .create = mqueue_create,
1240         .unlink = mqueue_unlink,
1241 };
1242
1243 static const struct file_operations mqueue_file_operations = {
1244         .flush = mqueue_flush_file,
1245         .poll = mqueue_poll_file,
1246         .read = mqueue_read_file,
1247 };
1248
1249 static const struct super_operations mqueue_super_ops = {
1250         .alloc_inode = mqueue_alloc_inode,
1251         .destroy_inode = mqueue_destroy_inode,
1252         .statfs = simple_statfs,
1253         .delete_inode = mqueue_delete_inode,
1254         .drop_inode = generic_delete_inode,
1255 };
1256
1257 static struct file_system_type mqueue_fs_type = {
1258         .name = "mqueue",
1259         .get_sb = mqueue_get_sb,
1260         .kill_sb = kill_litter_super,
1261 };
1262
1263 int mq_init_ns(struct ipc_namespace *ns)
1264 {
1265         ns->mq_queues_count  = 0;
1266         ns->mq_queues_max    = DFLT_QUEUESMAX;
1267         ns->mq_msg_max       = DFLT_MSGMAX;
1268         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1269
1270         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1271         if (IS_ERR(ns->mq_mnt)) {
1272                 int err = PTR_ERR(ns->mq_mnt);
1273                 ns->mq_mnt = NULL;
1274                 return err;
1275         }
1276         return 0;
1277 }
1278
1279 void mq_clear_sbinfo(struct ipc_namespace *ns)
1280 {
1281         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1282 }
1283
1284 void mq_put_mnt(struct ipc_namespace *ns)
1285 {
1286         mntput(ns->mq_mnt);
1287 }
1288
1289 static int __init init_mqueue_fs(void)
1290 {
1291         int error;
1292
1293         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1294                                 sizeof(struct mqueue_inode_info), 0,
1295                                 SLAB_HWCACHE_ALIGN, init_once);
1296         if (mqueue_inode_cachep == NULL)
1297                 return -ENOMEM;
1298
1299         /* ignore failures - they are not fatal */
1300         mq_sysctl_table = mq_register_sysctl_table();
1301
1302         error = register_filesystem(&mqueue_fs_type);
1303         if (error)
1304                 goto out_sysctl;
1305
1306         spin_lock_init(&mq_lock);
1307
1308         init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1309         if (IS_ERR(init_ipc_ns.mq_mnt)) {
1310                 error = PTR_ERR(init_ipc_ns.mq_mnt);
1311                 goto out_filesystem;
1312         }
1313
1314         return 0;
1315
1316 out_filesystem:
1317         unregister_filesystem(&mqueue_fs_type);
1318 out_sysctl:
1319         if (mq_sysctl_table)
1320                 unregister_sysctl_table(mq_sysctl_table);
1321         kmem_cache_destroy(mqueue_inode_cachep);
1322         return error;
1323 }
1324
1325 __initcall(init_mqueue_fs);