sfc: Wait at most 10ms for the MC to finish reading out MAC statistics
[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 #include <linux/slab.h>
36
37 #include <net/sock.h>
38 #include "util.h"
39
40 #define MQUEUE_MAGIC    0x19800202
41 #define DIRENT_SIZE     20
42 #define FILENT_SIZE     80
43
44 #define SEND            0
45 #define RECV            1
46
47 #define STATE_NONE      0
48 #define STATE_PENDING   1
49 #define STATE_READY     2
50
51 struct ext_wait_queue {         /* queue of sleeping tasks */
52         struct task_struct *task;
53         struct list_head list;
54         struct msg_msg *msg;    /* ptr of loaded message */
55         int state;              /* one of STATE_* values */
56 };
57
58 struct mqueue_inode_info {
59         spinlock_t lock;
60         struct inode vfs_inode;
61         wait_queue_head_t wait_q;
62
63         struct msg_msg **messages;
64         struct mq_attr attr;
65
66         struct sigevent notify;
67         struct pid* notify_owner;
68         struct user_struct *user;       /* user who created, for accounting */
69         struct sock *notify_sock;
70         struct sk_buff *notify_cookie;
71
72         /* for tasks waiting for free space and messages, respectively */
73         struct ext_wait_queue e_wait_q[2];
74
75         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
76 };
77
78 static const struct inode_operations mqueue_dir_inode_operations;
79 static const struct file_operations mqueue_file_operations;
80 static const struct super_operations mqueue_super_ops;
81 static void remove_notification(struct mqueue_inode_info *info);
82
83 static struct kmem_cache *mqueue_inode_cachep;
84
85 static struct ctl_table_header * mq_sysctl_table;
86
87 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
88 {
89         return container_of(inode, struct mqueue_inode_info, vfs_inode);
90 }
91
92 /*
93  * This routine should be called with the mq_lock held.
94  */
95 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
96 {
97         return get_ipc_ns(inode->i_sb->s_fs_info);
98 }
99
100 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
101 {
102         struct ipc_namespace *ns;
103
104         spin_lock(&mq_lock);
105         ns = __get_ns_from_inode(inode);
106         spin_unlock(&mq_lock);
107         return ns;
108 }
109
110 static struct inode *mqueue_get_inode(struct super_block *sb,
111                 struct ipc_namespace *ipc_ns, int mode,
112                 struct mq_attr *attr)
113 {
114         struct user_struct *u = current_user();
115         struct inode *inode;
116
117         inode = new_inode(sb);
118         if (inode) {
119                 inode->i_mode = mode;
120                 inode->i_uid = current_fsuid();
121                 inode->i_gid = current_fsgid();
122                 inode->i_mtime = inode->i_ctime = inode->i_atime =
123                                 CURRENT_TIME;
124
125                 if (S_ISREG(mode)) {
126                         struct mqueue_inode_info *info;
127                         struct task_struct *p = current;
128                         unsigned long mq_bytes, mq_msg_tblsz;
129
130                         inode->i_fop = &mqueue_file_operations;
131                         inode->i_size = FILENT_SIZE;
132                         /* mqueue specific info */
133                         info = MQUEUE_I(inode);
134                         spin_lock_init(&info->lock);
135                         init_waitqueue_head(&info->wait_q);
136                         INIT_LIST_HEAD(&info->e_wait_q[0].list);
137                         INIT_LIST_HEAD(&info->e_wait_q[1].list);
138                         info->notify_owner = NULL;
139                         info->qsize = 0;
140                         info->user = NULL;      /* set when all is ok */
141                         memset(&info->attr, 0, sizeof(info->attr));
142                         info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
143                         info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
144                         if (attr) {
145                                 info->attr.mq_maxmsg = attr->mq_maxmsg;
146                                 info->attr.mq_msgsize = attr->mq_msgsize;
147                         }
148                         mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
149                         info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
150                         if (!info->messages)
151                                 goto out_inode;
152
153                         mq_bytes = (mq_msg_tblsz +
154                                 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
155
156                         spin_lock(&mq_lock);
157                         if (u->mq_bytes + mq_bytes < u->mq_bytes ||
158                             u->mq_bytes + mq_bytes >
159                             task_rlimit(p, RLIMIT_MSGQUEUE)) {
160                                 spin_unlock(&mq_lock);
161                                 kfree(info->messages);
162                                 goto out_inode;
163                         }
164                         u->mq_bytes += mq_bytes;
165                         spin_unlock(&mq_lock);
166
167                         /* all is ok */
168                         info->user = get_uid(u);
169                 } else if (S_ISDIR(mode)) {
170                         inc_nlink(inode);
171                         /* Some things misbehave if size == 0 on a directory */
172                         inode->i_size = 2 * DIRENT_SIZE;
173                         inode->i_op = &mqueue_dir_inode_operations;
174                         inode->i_fop = &simple_dir_operations;
175                 }
176         }
177         return inode;
178 out_inode:
179         make_bad_inode(inode);
180         iput(inode);
181         return NULL;
182 }
183
184 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
185 {
186         struct inode *inode;
187         struct ipc_namespace *ns = data;
188         int error;
189
190         sb->s_blocksize = PAGE_CACHE_SIZE;
191         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
192         sb->s_magic = MQUEUE_MAGIC;
193         sb->s_op = &mqueue_super_ops;
194
195         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
196                                 NULL);
197         if (!inode) {
198                 error = -ENOMEM;
199                 goto out;
200         }
201
202         sb->s_root = d_alloc_root(inode);
203         if (!sb->s_root) {
204                 iput(inode);
205                 error = -ENOMEM;
206                 goto out;
207         }
208         error = 0;
209
210 out:
211         return error;
212 }
213
214 static int mqueue_get_sb(struct file_system_type *fs_type,
215                          int flags, const char *dev_name,
216                          void *data, struct vfsmount *mnt)
217 {
218         if (!(flags & MS_KERNMOUNT))
219                 data = current->nsproxy->ipc_ns;
220         return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);
221 }
222
223 static void init_once(void *foo)
224 {
225         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
226
227         inode_init_once(&p->vfs_inode);
228 }
229
230 static struct inode *mqueue_alloc_inode(struct super_block *sb)
231 {
232         struct mqueue_inode_info *ei;
233
234         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
235         if (!ei)
236                 return NULL;
237         return &ei->vfs_inode;
238 }
239
240 static void mqueue_destroy_inode(struct inode *inode)
241 {
242         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
243 }
244
245 static void mqueue_delete_inode(struct inode *inode)
246 {
247         struct mqueue_inode_info *info;
248         struct user_struct *user;
249         unsigned long mq_bytes;
250         int i;
251         struct ipc_namespace *ipc_ns;
252
253         if (S_ISDIR(inode->i_mode)) {
254                 clear_inode(inode);
255                 return;
256         }
257         ipc_ns = get_ns_from_inode(inode);
258         info = MQUEUE_I(inode);
259         spin_lock(&info->lock);
260         for (i = 0; i < info->attr.mq_curmsgs; i++)
261                 free_msg(info->messages[i]);
262         kfree(info->messages);
263         spin_unlock(&info->lock);
264
265         clear_inode(inode);
266
267         /* Total amount of bytes accounted for the mqueue */
268         mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
269             + info->attr.mq_msgsize);
270         user = info->user;
271         if (user) {
272                 spin_lock(&mq_lock);
273                 user->mq_bytes -= mq_bytes;
274                 /*
275                  * get_ns_from_inode() ensures that the
276                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
277                  * to which we now hold a reference, or it is NULL.
278                  * We can't put it here under mq_lock, though.
279                  */
280                 if (ipc_ns)
281                         ipc_ns->mq_queues_count--;
282                 spin_unlock(&mq_lock);
283                 free_uid(user);
284         }
285         if (ipc_ns)
286                 put_ipc_ns(ipc_ns);
287 }
288
289 static int mqueue_create(struct inode *dir, struct dentry *dentry,
290                                 int mode, struct nameidata *nd)
291 {
292         struct inode *inode;
293         struct mq_attr *attr = dentry->d_fsdata;
294         int error;
295         struct ipc_namespace *ipc_ns;
296
297         spin_lock(&mq_lock);
298         ipc_ns = __get_ns_from_inode(dir);
299         if (!ipc_ns) {
300                 error = -EACCES;
301                 goto out_unlock;
302         }
303         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
304                         !capable(CAP_SYS_RESOURCE)) {
305                 error = -ENOSPC;
306                 goto out_unlock;
307         }
308         ipc_ns->mq_queues_count++;
309         spin_unlock(&mq_lock);
310
311         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
312         if (!inode) {
313                 error = -ENOMEM;
314                 spin_lock(&mq_lock);
315                 ipc_ns->mq_queues_count--;
316                 goto out_unlock;
317         }
318
319         put_ipc_ns(ipc_ns);
320         dir->i_size += DIRENT_SIZE;
321         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
322
323         d_instantiate(dentry, inode);
324         dget(dentry);
325         return 0;
326 out_unlock:
327         spin_unlock(&mq_lock);
328         if (ipc_ns)
329                 put_ipc_ns(ipc_ns);
330         return error;
331 }
332
333 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
334 {
335         struct inode *inode = dentry->d_inode;
336
337         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
338         dir->i_size -= DIRENT_SIZE;
339         drop_nlink(inode);
340         dput(dentry);
341         return 0;
342 }
343
344 /*
345 *       This is routine for system read from queue file.
346 *       To avoid mess with doing here some sort of mq_receive we allow
347 *       to read only queue size & notification info (the only values
348 *       that are interesting from user point of view and aren't accessible
349 *       through std routines)
350 */
351 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
352                                 size_t count, loff_t *off)
353 {
354         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
355         char buffer[FILENT_SIZE];
356         ssize_t ret;
357
358         spin_lock(&info->lock);
359         snprintf(buffer, sizeof(buffer),
360                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
361                         info->qsize,
362                         info->notify_owner ? info->notify.sigev_notify : 0,
363                         (info->notify_owner &&
364                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
365                                 info->notify.sigev_signo : 0,
366                         pid_vnr(info->notify_owner));
367         spin_unlock(&info->lock);
368         buffer[sizeof(buffer)-1] = '\0';
369
370         ret = simple_read_from_buffer(u_data, count, off, buffer,
371                                 strlen(buffer));
372         if (ret <= 0)
373                 return ret;
374
375         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
376         return ret;
377 }
378
379 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
380 {
381         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
382
383         spin_lock(&info->lock);
384         if (task_tgid(current) == info->notify_owner)
385                 remove_notification(info);
386
387         spin_unlock(&info->lock);
388         return 0;
389 }
390
391 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
392 {
393         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
394         int retval = 0;
395
396         poll_wait(filp, &info->wait_q, poll_tab);
397
398         spin_lock(&info->lock);
399         if (info->attr.mq_curmsgs)
400                 retval = POLLIN | POLLRDNORM;
401
402         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
403                 retval |= POLLOUT | POLLWRNORM;
404         spin_unlock(&info->lock);
405
406         return retval;
407 }
408
409 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
410 static void wq_add(struct mqueue_inode_info *info, int sr,
411                         struct ext_wait_queue *ewp)
412 {
413         struct ext_wait_queue *walk;
414
415         ewp->task = current;
416
417         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
418                 if (walk->task->static_prio <= current->static_prio) {
419                         list_add_tail(&ewp->list, &walk->list);
420                         return;
421                 }
422         }
423         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
424 }
425
426 /*
427  * Puts current task to sleep. Caller must hold queue lock. After return
428  * lock isn't held.
429  * sr: SEND or RECV
430  */
431 static int wq_sleep(struct mqueue_inode_info *info, int sr,
432                         long timeout, struct ext_wait_queue *ewp)
433 {
434         int retval;
435         signed long time;
436
437         wq_add(info, sr, ewp);
438
439         for (;;) {
440                 set_current_state(TASK_INTERRUPTIBLE);
441
442                 spin_unlock(&info->lock);
443                 time = schedule_timeout(timeout);
444
445                 while (ewp->state == STATE_PENDING)
446                         cpu_relax();
447
448                 if (ewp->state == STATE_READY) {
449                         retval = 0;
450                         goto out;
451                 }
452                 spin_lock(&info->lock);
453                 if (ewp->state == STATE_READY) {
454                         retval = 0;
455                         goto out_unlock;
456                 }
457                 if (signal_pending(current)) {
458                         retval = -ERESTARTSYS;
459                         break;
460                 }
461                 if (time == 0) {
462                         retval = -ETIMEDOUT;
463                         break;
464                 }
465         }
466         list_del(&ewp->list);
467 out_unlock:
468         spin_unlock(&info->lock);
469 out:
470         return retval;
471 }
472
473 /*
474  * Returns waiting task that should be serviced first or NULL if none exists
475  */
476 static struct ext_wait_queue *wq_get_first_waiter(
477                 struct mqueue_inode_info *info, int sr)
478 {
479         struct list_head *ptr;
480
481         ptr = info->e_wait_q[sr].list.prev;
482         if (ptr == &info->e_wait_q[sr].list)
483                 return NULL;
484         return list_entry(ptr, struct ext_wait_queue, list);
485 }
486
487 /* Auxiliary functions to manipulate messages' list */
488 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
489 {
490         int k;
491
492         k = info->attr.mq_curmsgs - 1;
493         while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
494                 info->messages[k + 1] = info->messages[k];
495                 k--;
496         }
497         info->attr.mq_curmsgs++;
498         info->qsize += ptr->m_ts;
499         info->messages[k + 1] = ptr;
500 }
501
502 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
503 {
504         info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
505         return info->messages[info->attr.mq_curmsgs];
506 }
507
508 static inline void set_cookie(struct sk_buff *skb, char code)
509 {
510         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
511 }
512
513 /*
514  * The next function is only to split too long sys_mq_timedsend
515  */
516 static void __do_notify(struct mqueue_inode_info *info)
517 {
518         /* notification
519          * invoked when there is registered process and there isn't process
520          * waiting synchronously for message AND state of queue changed from
521          * empty to not empty. Here we are sure that no one is waiting
522          * synchronously. */
523         if (info->notify_owner &&
524             info->attr.mq_curmsgs == 1) {
525                 struct siginfo sig_i;
526                 switch (info->notify.sigev_notify) {
527                 case SIGEV_NONE:
528                         break;
529                 case SIGEV_SIGNAL:
530                         /* sends signal */
531
532                         sig_i.si_signo = info->notify.sigev_signo;
533                         sig_i.si_errno = 0;
534                         sig_i.si_code = SI_MESGQ;
535                         sig_i.si_value = info->notify.sigev_value;
536                         sig_i.si_pid = task_tgid_nr_ns(current,
537                                                 ns_of_pid(info->notify_owner));
538                         sig_i.si_uid = current_uid();
539
540                         kill_pid_info(info->notify.sigev_signo,
541                                       &sig_i, info->notify_owner);
542                         break;
543                 case SIGEV_THREAD:
544                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
545                         netlink_sendskb(info->notify_sock, info->notify_cookie);
546                         break;
547                 }
548                 /* after notification unregisters process */
549                 put_pid(info->notify_owner);
550                 info->notify_owner = NULL;
551         }
552         wake_up(&info->wait_q);
553 }
554
555 static long prepare_timeout(struct timespec *p)
556 {
557         struct timespec nowts;
558         long timeout;
559
560         if (p) {
561                 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
562                         || p->tv_nsec >= NSEC_PER_SEC))
563                         return -EINVAL;
564                 nowts = CURRENT_TIME;
565                 /* first subtract as jiffies can't be too big */
566                 p->tv_sec -= nowts.tv_sec;
567                 if (p->tv_nsec < nowts.tv_nsec) {
568                         p->tv_nsec += NSEC_PER_SEC;
569                         p->tv_sec--;
570                 }
571                 p->tv_nsec -= nowts.tv_nsec;
572                 if (p->tv_sec < 0)
573                         return 0;
574
575                 timeout = timespec_to_jiffies(p) + 1;
576         } else
577                 return MAX_SCHEDULE_TIMEOUT;
578
579         return timeout;
580 }
581
582 static void remove_notification(struct mqueue_inode_info *info)
583 {
584         if (info->notify_owner != NULL &&
585             info->notify.sigev_notify == SIGEV_THREAD) {
586                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
587                 netlink_sendskb(info->notify_sock, info->notify_cookie);
588         }
589         put_pid(info->notify_owner);
590         info->notify_owner = NULL;
591 }
592
593 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
594 {
595         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
596                 return 0;
597         if (capable(CAP_SYS_RESOURCE)) {
598                 if (attr->mq_maxmsg > HARD_MSGMAX)
599                         return 0;
600         } else {
601                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
602                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
603                         return 0;
604         }
605         /* check for overflow */
606         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
607                 return 0;
608         if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
609             + sizeof (struct msg_msg *))) <
610             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
611                 return 0;
612         return 1;
613 }
614
615 /*
616  * Invoked when creating a new queue via sys_mq_open
617  */
618 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
619                         struct dentry *dentry, int oflag, mode_t mode,
620                         struct mq_attr *attr)
621 {
622         const struct cred *cred = current_cred();
623         struct file *result;
624         int ret;
625
626         if (attr) {
627                 if (!mq_attr_ok(ipc_ns, attr)) {
628                         ret = -EINVAL;
629                         goto out;
630                 }
631                 /* store for use during create */
632                 dentry->d_fsdata = attr;
633         }
634
635         mode &= ~current_umask();
636         ret = mnt_want_write(ipc_ns->mq_mnt);
637         if (ret)
638                 goto out;
639         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
640         dentry->d_fsdata = NULL;
641         if (ret)
642                 goto out_drop_write;
643
644         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
645         /*
646          * dentry_open() took a persistent mnt_want_write(),
647          * so we can now drop this one.
648          */
649         mnt_drop_write(ipc_ns->mq_mnt);
650         return result;
651
652 out_drop_write:
653         mnt_drop_write(ipc_ns->mq_mnt);
654 out:
655         dput(dentry);
656         mntput(ipc_ns->mq_mnt);
657         return ERR_PTR(ret);
658 }
659
660 /* Opens existing queue */
661 static struct file *do_open(struct ipc_namespace *ipc_ns,
662                                 struct dentry *dentry, int oflag)
663 {
664         int ret;
665         const struct cred *cred = current_cred();
666
667         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
668                                                   MAY_READ | MAY_WRITE };
669
670         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
671                 ret = -EINVAL;
672                 goto err;
673         }
674
675         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
676                 ret = -EACCES;
677                 goto err;
678         }
679
680         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
681
682 err:
683         dput(dentry);
684         mntput(ipc_ns->mq_mnt);
685         return ERR_PTR(ret);
686 }
687
688 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
689                 struct mq_attr __user *, u_attr)
690 {
691         struct dentry *dentry;
692         struct file *filp;
693         char *name;
694         struct mq_attr attr;
695         int fd, error;
696         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
697
698         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
699                 return -EFAULT;
700
701         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
702
703         if (IS_ERR(name = getname(u_name)))
704                 return PTR_ERR(name);
705
706         fd = get_unused_fd_flags(O_CLOEXEC);
707         if (fd < 0)
708                 goto out_putname;
709
710         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
711         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
712         if (IS_ERR(dentry)) {
713                 error = PTR_ERR(dentry);
714                 goto out_putfd;
715         }
716         mntget(ipc_ns->mq_mnt);
717
718         if (oflag & O_CREAT) {
719                 if (dentry->d_inode) {  /* entry already exists */
720                         audit_inode(name, dentry);
721                         if (oflag & O_EXCL) {
722                                 error = -EEXIST;
723                                 goto out;
724                         }
725                         filp = do_open(ipc_ns, dentry, oflag);
726                 } else {
727                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
728                                                 dentry, oflag, mode,
729                                                 u_attr ? &attr : NULL);
730                 }
731         } else {
732                 if (!dentry->d_inode) {
733                         error = -ENOENT;
734                         goto out;
735                 }
736                 audit_inode(name, dentry);
737                 filp = do_open(ipc_ns, dentry, oflag);
738         }
739
740         if (IS_ERR(filp)) {
741                 error = PTR_ERR(filp);
742                 goto out_putfd;
743         }
744
745         fd_install(fd, filp);
746         goto out_upsem;
747
748 out:
749         dput(dentry);
750         mntput(ipc_ns->mq_mnt);
751 out_putfd:
752         put_unused_fd(fd);
753         fd = error;
754 out_upsem:
755         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
756 out_putname:
757         putname(name);
758         return fd;
759 }
760
761 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
762 {
763         int err;
764         char *name;
765         struct dentry *dentry;
766         struct inode *inode = NULL;
767         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
768
769         name = getname(u_name);
770         if (IS_ERR(name))
771                 return PTR_ERR(name);
772
773         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
774                         I_MUTEX_PARENT);
775         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
776         if (IS_ERR(dentry)) {
777                 err = PTR_ERR(dentry);
778                 goto out_unlock;
779         }
780
781         if (!dentry->d_inode) {
782                 err = -ENOENT;
783                 goto out_err;
784         }
785
786         inode = dentry->d_inode;
787         if (inode)
788                 atomic_inc(&inode->i_count);
789         err = mnt_want_write(ipc_ns->mq_mnt);
790         if (err)
791                 goto out_err;
792         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
793         mnt_drop_write(ipc_ns->mq_mnt);
794 out_err:
795         dput(dentry);
796
797 out_unlock:
798         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
799         putname(name);
800         if (inode)
801                 iput(inode);
802
803         return err;
804 }
805
806 /* Pipelined send and receive functions.
807  *
808  * If a receiver finds no waiting message, then it registers itself in the
809  * list of waiting receivers. A sender checks that list before adding the new
810  * message into the message array. If there is a waiting receiver, then it
811  * bypasses the message array and directly hands the message over to the
812  * receiver.
813  * The receiver accepts the message and returns without grabbing the queue
814  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
815  * are necessary. The same algorithm is used for sysv semaphores, see
816  * ipc/sem.c for more details.
817  *
818  * The same algorithm is used for senders.
819  */
820
821 /* pipelined_send() - send a message directly to the task waiting in
822  * sys_mq_timedreceive() (without inserting message into a queue).
823  */
824 static inline void pipelined_send(struct mqueue_inode_info *info,
825                                   struct msg_msg *message,
826                                   struct ext_wait_queue *receiver)
827 {
828         receiver->msg = message;
829         list_del(&receiver->list);
830         receiver->state = STATE_PENDING;
831         wake_up_process(receiver->task);
832         smp_wmb();
833         receiver->state = STATE_READY;
834 }
835
836 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
837  * gets its message and put to the queue (we have one free place for sure). */
838 static inline void pipelined_receive(struct mqueue_inode_info *info)
839 {
840         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
841
842         if (!sender) {
843                 /* for poll */
844                 wake_up_interruptible(&info->wait_q);
845                 return;
846         }
847         msg_insert(sender->msg, info);
848         list_del(&sender->list);
849         sender->state = STATE_PENDING;
850         wake_up_process(sender->task);
851         smp_wmb();
852         sender->state = STATE_READY;
853 }
854
855 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
856                 size_t, msg_len, unsigned int, msg_prio,
857                 const struct timespec __user *, u_abs_timeout)
858 {
859         struct file *filp;
860         struct inode *inode;
861         struct ext_wait_queue wait;
862         struct ext_wait_queue *receiver;
863         struct msg_msg *msg_ptr;
864         struct mqueue_inode_info *info;
865         struct timespec ts, *p = NULL;
866         long timeout;
867         int ret;
868
869         if (u_abs_timeout) {
870                 if (copy_from_user(&ts, u_abs_timeout, 
871                                         sizeof(struct timespec)))
872                         return -EFAULT;
873                 p = &ts;
874         }
875
876         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
877                 return -EINVAL;
878
879         audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
880         timeout = prepare_timeout(p);
881
882         filp = fget(mqdes);
883         if (unlikely(!filp)) {
884                 ret = -EBADF;
885                 goto out;
886         }
887
888         inode = filp->f_path.dentry->d_inode;
889         if (unlikely(filp->f_op != &mqueue_file_operations)) {
890                 ret = -EBADF;
891                 goto out_fput;
892         }
893         info = MQUEUE_I(inode);
894         audit_inode(NULL, filp->f_path.dentry);
895
896         if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
897                 ret = -EBADF;
898                 goto out_fput;
899         }
900
901         if (unlikely(msg_len > info->attr.mq_msgsize)) {
902                 ret = -EMSGSIZE;
903                 goto out_fput;
904         }
905
906         /* First try to allocate memory, before doing anything with
907          * existing queues. */
908         msg_ptr = load_msg(u_msg_ptr, msg_len);
909         if (IS_ERR(msg_ptr)) {
910                 ret = PTR_ERR(msg_ptr);
911                 goto out_fput;
912         }
913         msg_ptr->m_ts = msg_len;
914         msg_ptr->m_type = msg_prio;
915
916         spin_lock(&info->lock);
917
918         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
919                 if (filp->f_flags & O_NONBLOCK) {
920                         spin_unlock(&info->lock);
921                         ret = -EAGAIN;
922                 } else if (unlikely(timeout < 0)) {
923                         spin_unlock(&info->lock);
924                         ret = timeout;
925                 } else {
926                         wait.task = current;
927                         wait.msg = (void *) msg_ptr;
928                         wait.state = STATE_NONE;
929                         ret = wq_sleep(info, SEND, timeout, &wait);
930                 }
931                 if (ret < 0)
932                         free_msg(msg_ptr);
933         } else {
934                 receiver = wq_get_first_waiter(info, RECV);
935                 if (receiver) {
936                         pipelined_send(info, msg_ptr, receiver);
937                 } else {
938                         /* adds message to the queue */
939                         msg_insert(msg_ptr, info);
940                         __do_notify(info);
941                 }
942                 inode->i_atime = inode->i_mtime = inode->i_ctime =
943                                 CURRENT_TIME;
944                 spin_unlock(&info->lock);
945                 ret = 0;
946         }
947 out_fput:
948         fput(filp);
949 out:
950         return ret;
951 }
952
953 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
954                 size_t, msg_len, unsigned int __user *, u_msg_prio,
955                 const struct timespec __user *, u_abs_timeout)
956 {
957         long timeout;
958         ssize_t ret;
959         struct msg_msg *msg_ptr;
960         struct file *filp;
961         struct inode *inode;
962         struct mqueue_inode_info *info;
963         struct ext_wait_queue wait;
964         struct timespec ts, *p = NULL;
965
966         if (u_abs_timeout) {
967                 if (copy_from_user(&ts, u_abs_timeout, 
968                                         sizeof(struct timespec)))
969                         return -EFAULT;
970                 p = &ts;
971         }
972
973         audit_mq_sendrecv(mqdes, msg_len, 0, p);
974         timeout = prepare_timeout(p);
975
976         filp = fget(mqdes);
977         if (unlikely(!filp)) {
978                 ret = -EBADF;
979                 goto out;
980         }
981
982         inode = filp->f_path.dentry->d_inode;
983         if (unlikely(filp->f_op != &mqueue_file_operations)) {
984                 ret = -EBADF;
985                 goto out_fput;
986         }
987         info = MQUEUE_I(inode);
988         audit_inode(NULL, filp->f_path.dentry);
989
990         if (unlikely(!(filp->f_mode & FMODE_READ))) {
991                 ret = -EBADF;
992                 goto out_fput;
993         }
994
995         /* checks if buffer is big enough */
996         if (unlikely(msg_len < info->attr.mq_msgsize)) {
997                 ret = -EMSGSIZE;
998                 goto out_fput;
999         }
1000
1001         spin_lock(&info->lock);
1002         if (info->attr.mq_curmsgs == 0) {
1003                 if (filp->f_flags & O_NONBLOCK) {
1004                         spin_unlock(&info->lock);
1005                         ret = -EAGAIN;
1006                         msg_ptr = NULL;
1007                 } else if (unlikely(timeout < 0)) {
1008                         spin_unlock(&info->lock);
1009                         ret = timeout;
1010                         msg_ptr = NULL;
1011                 } else {
1012                         wait.task = current;
1013                         wait.state = STATE_NONE;
1014                         ret = wq_sleep(info, RECV, timeout, &wait);
1015                         msg_ptr = wait.msg;
1016                 }
1017         } else {
1018                 msg_ptr = msg_get(info);
1019
1020                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1021                                 CURRENT_TIME;
1022
1023                 /* There is now free space in queue. */
1024                 pipelined_receive(info);
1025                 spin_unlock(&info->lock);
1026                 ret = 0;
1027         }
1028         if (ret == 0) {
1029                 ret = msg_ptr->m_ts;
1030
1031                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1032                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1033                         ret = -EFAULT;
1034                 }
1035                 free_msg(msg_ptr);
1036         }
1037 out_fput:
1038         fput(filp);
1039 out:
1040         return ret;
1041 }
1042
1043 /*
1044  * Notes: the case when user wants us to deregister (with NULL as pointer)
1045  * and he isn't currently owner of notification, will be silently discarded.
1046  * It isn't explicitly defined in the POSIX.
1047  */
1048 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1049                 const struct sigevent __user *, u_notification)
1050 {
1051         int ret;
1052         struct file *filp;
1053         struct sock *sock;
1054         struct inode *inode;
1055         struct sigevent notification;
1056         struct mqueue_inode_info *info;
1057         struct sk_buff *nc;
1058
1059         if (u_notification) {
1060                 if (copy_from_user(&notification, u_notification,
1061                                         sizeof(struct sigevent)))
1062                         return -EFAULT;
1063         }
1064
1065         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1066
1067         nc = NULL;
1068         sock = NULL;
1069         if (u_notification != NULL) {
1070                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1071                              notification.sigev_notify != SIGEV_SIGNAL &&
1072                              notification.sigev_notify != SIGEV_THREAD))
1073                         return -EINVAL;
1074                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1075                         !valid_signal(notification.sigev_signo)) {
1076                         return -EINVAL;
1077                 }
1078                 if (notification.sigev_notify == SIGEV_THREAD) {
1079                         long timeo;
1080
1081                         /* create the notify skb */
1082                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1083                         if (!nc) {
1084                                 ret = -ENOMEM;
1085                                 goto out;
1086                         }
1087                         if (copy_from_user(nc->data,
1088                                         notification.sigev_value.sival_ptr,
1089                                         NOTIFY_COOKIE_LEN)) {
1090                                 ret = -EFAULT;
1091                                 goto out;
1092                         }
1093
1094                         /* TODO: add a header? */
1095                         skb_put(nc, NOTIFY_COOKIE_LEN);
1096                         /* and attach it to the socket */
1097 retry:
1098                         filp = fget(notification.sigev_signo);
1099                         if (!filp) {
1100                                 ret = -EBADF;
1101                                 goto out;
1102                         }
1103                         sock = netlink_getsockbyfilp(filp);
1104                         fput(filp);
1105                         if (IS_ERR(sock)) {
1106                                 ret = PTR_ERR(sock);
1107                                 sock = NULL;
1108                                 goto out;
1109                         }
1110
1111                         timeo = MAX_SCHEDULE_TIMEOUT;
1112                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1113                         if (ret == 1)
1114                                 goto retry;
1115                         if (ret) {
1116                                 sock = NULL;
1117                                 nc = NULL;
1118                                 goto out;
1119                         }
1120                 }
1121         }
1122
1123         filp = fget(mqdes);
1124         if (!filp) {
1125                 ret = -EBADF;
1126                 goto out;
1127         }
1128
1129         inode = filp->f_path.dentry->d_inode;
1130         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1131                 ret = -EBADF;
1132                 goto out_fput;
1133         }
1134         info = MQUEUE_I(inode);
1135
1136         ret = 0;
1137         spin_lock(&info->lock);
1138         if (u_notification == NULL) {
1139                 if (info->notify_owner == task_tgid(current)) {
1140                         remove_notification(info);
1141                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1142                 }
1143         } else if (info->notify_owner != NULL) {
1144                 ret = -EBUSY;
1145         } else {
1146                 switch (notification.sigev_notify) {
1147                 case SIGEV_NONE:
1148                         info->notify.sigev_notify = SIGEV_NONE;
1149                         break;
1150                 case SIGEV_THREAD:
1151                         info->notify_sock = sock;
1152                         info->notify_cookie = nc;
1153                         sock = NULL;
1154                         nc = NULL;
1155                         info->notify.sigev_notify = SIGEV_THREAD;
1156                         break;
1157                 case SIGEV_SIGNAL:
1158                         info->notify.sigev_signo = notification.sigev_signo;
1159                         info->notify.sigev_value = notification.sigev_value;
1160                         info->notify.sigev_notify = SIGEV_SIGNAL;
1161                         break;
1162                 }
1163
1164                 info->notify_owner = get_pid(task_tgid(current));
1165                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1166         }
1167         spin_unlock(&info->lock);
1168 out_fput:
1169         fput(filp);
1170 out:
1171         if (sock) {
1172                 netlink_detachskb(sock, nc);
1173         } else if (nc) {
1174                 dev_kfree_skb(nc);
1175         }
1176         return ret;
1177 }
1178
1179 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1180                 const struct mq_attr __user *, u_mqstat,
1181                 struct mq_attr __user *, u_omqstat)
1182 {
1183         int ret;
1184         struct mq_attr mqstat, omqstat;
1185         struct file *filp;
1186         struct inode *inode;
1187         struct mqueue_inode_info *info;
1188
1189         if (u_mqstat != NULL) {
1190                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1191                         return -EFAULT;
1192                 if (mqstat.mq_flags & (~O_NONBLOCK))
1193                         return -EINVAL;
1194         }
1195
1196         filp = fget(mqdes);
1197         if (!filp) {
1198                 ret = -EBADF;
1199                 goto out;
1200         }
1201
1202         inode = filp->f_path.dentry->d_inode;
1203         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1204                 ret = -EBADF;
1205                 goto out_fput;
1206         }
1207         info = MQUEUE_I(inode);
1208
1209         spin_lock(&info->lock);
1210
1211         omqstat = info->attr;
1212         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1213         if (u_mqstat) {
1214                 audit_mq_getsetattr(mqdes, &mqstat);
1215                 spin_lock(&filp->f_lock);
1216                 if (mqstat.mq_flags & O_NONBLOCK)
1217                         filp->f_flags |= O_NONBLOCK;
1218                 else
1219                         filp->f_flags &= ~O_NONBLOCK;
1220                 spin_unlock(&filp->f_lock);
1221
1222                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1223         }
1224
1225         spin_unlock(&info->lock);
1226
1227         ret = 0;
1228         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1229                                                 sizeof(struct mq_attr)))
1230                 ret = -EFAULT;
1231
1232 out_fput:
1233         fput(filp);
1234 out:
1235         return ret;
1236 }
1237
1238 static const struct inode_operations mqueue_dir_inode_operations = {
1239         .lookup = simple_lookup,
1240         .create = mqueue_create,
1241         .unlink = mqueue_unlink,
1242 };
1243
1244 static const struct file_operations mqueue_file_operations = {
1245         .flush = mqueue_flush_file,
1246         .poll = mqueue_poll_file,
1247         .read = mqueue_read_file,
1248 };
1249
1250 static const struct super_operations mqueue_super_ops = {
1251         .alloc_inode = mqueue_alloc_inode,
1252         .destroy_inode = mqueue_destroy_inode,
1253         .statfs = simple_statfs,
1254         .delete_inode = mqueue_delete_inode,
1255         .drop_inode = generic_delete_inode,
1256 };
1257
1258 static struct file_system_type mqueue_fs_type = {
1259         .name = "mqueue",
1260         .get_sb = mqueue_get_sb,
1261         .kill_sb = kill_litter_super,
1262 };
1263
1264 int mq_init_ns(struct ipc_namespace *ns)
1265 {
1266         ns->mq_queues_count  = 0;
1267         ns->mq_queues_max    = DFLT_QUEUESMAX;
1268         ns->mq_msg_max       = DFLT_MSGMAX;
1269         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1270
1271         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1272         if (IS_ERR(ns->mq_mnt)) {
1273                 int err = PTR_ERR(ns->mq_mnt);
1274                 ns->mq_mnt = NULL;
1275                 return err;
1276         }
1277         return 0;
1278 }
1279
1280 void mq_clear_sbinfo(struct ipc_namespace *ns)
1281 {
1282         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1283 }
1284
1285 void mq_put_mnt(struct ipc_namespace *ns)
1286 {
1287         mntput(ns->mq_mnt);
1288 }
1289
1290 static int __init init_mqueue_fs(void)
1291 {
1292         int error;
1293
1294         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1295                                 sizeof(struct mqueue_inode_info), 0,
1296                                 SLAB_HWCACHE_ALIGN, init_once);
1297         if (mqueue_inode_cachep == NULL)
1298                 return -ENOMEM;
1299
1300         /* ignore failures - they are not fatal */
1301         mq_sysctl_table = mq_register_sysctl_table();
1302
1303         error = register_filesystem(&mqueue_fs_type);
1304         if (error)
1305                 goto out_sysctl;
1306
1307         spin_lock_init(&mq_lock);
1308
1309         init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1310         if (IS_ERR(init_ipc_ns.mq_mnt)) {
1311                 error = PTR_ERR(init_ipc_ns.mq_mnt);
1312                 goto out_filesystem;
1313         }
1314
1315         return 0;
1316
1317 out_filesystem:
1318         unregister_filesystem(&mqueue_fs_type);
1319 out_sysctl:
1320         if (mq_sysctl_table)
1321                 unregister_sysctl_table(mq_sysctl_table);
1322         kmem_cache_destroy(mqueue_inode_cachep);
1323         return error;
1324 }
1325
1326 __initcall(init_mqueue_fs);