ARM: tegra3: remove <board>-throttle_list_init functions
[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/user_namespace.h>
36 #include <linux/slab.h>
37
38 #include <net/sock.h>
39 #include "util.h"
40
41 #define MQUEUE_MAGIC    0x19800202
42 #define DIRENT_SIZE     20
43 #define FILENT_SIZE     80
44
45 #define SEND            0
46 #define RECV            1
47
48 #define STATE_NONE      0
49 #define STATE_PENDING   1
50 #define STATE_READY     2
51
52 struct ext_wait_queue {         /* queue of sleeping tasks */
53         struct task_struct *task;
54         struct list_head list;
55         struct msg_msg *msg;    /* ptr of loaded message */
56         int state;              /* one of STATE_* values */
57 };
58
59 struct mqueue_inode_info {
60         spinlock_t lock;
61         struct inode vfs_inode;
62         wait_queue_head_t wait_q;
63
64         struct msg_msg **messages;
65         struct mq_attr attr;
66
67         struct sigevent notify;
68         struct pid* notify_owner;
69         struct user_struct *user;       /* user who created, for accounting */
70         struct sock *notify_sock;
71         struct sk_buff *notify_cookie;
72
73         /* for tasks waiting for free space and messages, respectively */
74         struct ext_wait_queue e_wait_q[2];
75
76         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
77 };
78
79 static const struct inode_operations mqueue_dir_inode_operations;
80 static const struct file_operations mqueue_file_operations;
81 static const struct super_operations mqueue_super_ops;
82 static void remove_notification(struct mqueue_inode_info *info);
83
84 static struct kmem_cache *mqueue_inode_cachep;
85
86 static struct ctl_table_header * mq_sysctl_table;
87
88 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
89 {
90         return container_of(inode, struct mqueue_inode_info, vfs_inode);
91 }
92
93 /*
94  * This routine should be called with the mq_lock held.
95  */
96 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
97 {
98         return get_ipc_ns(inode->i_sb->s_fs_info);
99 }
100
101 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
102 {
103         struct ipc_namespace *ns;
104
105         spin_lock(&mq_lock);
106         ns = __get_ns_from_inode(inode);
107         spin_unlock(&mq_lock);
108         return ns;
109 }
110
111 static struct inode *mqueue_get_inode(struct super_block *sb,
112                 struct ipc_namespace *ipc_ns, umode_t mode,
113                 struct mq_attr *attr)
114 {
115         struct user_struct *u = current_user();
116         struct inode *inode;
117         int ret = -ENOMEM;
118
119         inode = new_inode(sb);
120         if (!inode)
121                 goto err;
122
123         inode->i_ino = get_next_ino();
124         inode->i_mode = mode;
125         inode->i_uid = current_fsuid();
126         inode->i_gid = current_fsgid();
127         inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
128
129         if (S_ISREG(mode)) {
130                 struct mqueue_inode_info *info;
131                 unsigned long mq_bytes, mq_msg_tblsz;
132
133                 inode->i_fop = &mqueue_file_operations;
134                 inode->i_size = FILENT_SIZE;
135                 /* mqueue specific info */
136                 info = MQUEUE_I(inode);
137                 spin_lock_init(&info->lock);
138                 init_waitqueue_head(&info->wait_q);
139                 INIT_LIST_HEAD(&info->e_wait_q[0].list);
140                 INIT_LIST_HEAD(&info->e_wait_q[1].list);
141                 info->notify_owner = NULL;
142                 info->qsize = 0;
143                 info->user = NULL;      /* set when all is ok */
144                 memset(&info->attr, 0, sizeof(info->attr));
145                 info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
146                 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
147                 if (attr) {
148                         info->attr.mq_maxmsg = attr->mq_maxmsg;
149                         info->attr.mq_msgsize = attr->mq_msgsize;
150                 }
151                 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
152                 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
153                 if (!info->messages)
154                         goto out_inode;
155
156                 mq_bytes = (mq_msg_tblsz +
157                         (info->attr.mq_maxmsg * info->attr.mq_msgsize));
158
159                 spin_lock(&mq_lock);
160                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
161                     u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
162                         spin_unlock(&mq_lock);
163                         /* mqueue_evict_inode() releases info->messages */
164                         ret = -EMFILE;
165                         goto out_inode;
166                 }
167                 u->mq_bytes += mq_bytes;
168                 spin_unlock(&mq_lock);
169
170                 /* all is ok */
171                 info->user = get_uid(u);
172         } else if (S_ISDIR(mode)) {
173                 inc_nlink(inode);
174                 /* Some things misbehave if size == 0 on a directory */
175                 inode->i_size = 2 * DIRENT_SIZE;
176                 inode->i_op = &mqueue_dir_inode_operations;
177                 inode->i_fop = &simple_dir_operations;
178         }
179
180         return inode;
181 out_inode:
182         iput(inode);
183 err:
184         return ERR_PTR(ret);
185 }
186
187 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
188 {
189         struct inode *inode;
190         struct ipc_namespace *ns = data;
191
192         sb->s_blocksize = PAGE_CACHE_SIZE;
193         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
194         sb->s_magic = MQUEUE_MAGIC;
195         sb->s_op = &mqueue_super_ops;
196
197         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
198         if (IS_ERR(inode))
199                 return PTR_ERR(inode);
200
201         sb->s_root = d_make_root(inode);
202         if (!sb->s_root)
203                 return -ENOMEM;
204         return 0;
205 }
206
207 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
208                          int flags, const char *dev_name,
209                          void *data)
210 {
211         if (!(flags & MS_KERNMOUNT))
212                 data = current->nsproxy->ipc_ns;
213         return mount_ns(fs_type, flags, data, mqueue_fill_super);
214 }
215
216 static void init_once(void *foo)
217 {
218         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
219
220         inode_init_once(&p->vfs_inode);
221 }
222
223 static struct inode *mqueue_alloc_inode(struct super_block *sb)
224 {
225         struct mqueue_inode_info *ei;
226
227         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
228         if (!ei)
229                 return NULL;
230         return &ei->vfs_inode;
231 }
232
233 static void mqueue_i_callback(struct rcu_head *head)
234 {
235         struct inode *inode = container_of(head, struct inode, i_rcu);
236         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
237 }
238
239 static void mqueue_destroy_inode(struct inode *inode)
240 {
241         call_rcu(&inode->i_rcu, mqueue_i_callback);
242 }
243
244 static void mqueue_evict_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         end_writeback(inode);
253
254         if (S_ISDIR(inode->i_mode))
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         /* Total amount of bytes accounted for the mqueue */
266         mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
267             + info->attr.mq_msgsize);
268         user = info->user;
269         if (user) {
270                 spin_lock(&mq_lock);
271                 user->mq_bytes -= mq_bytes;
272                 /*
273                  * get_ns_from_inode() ensures that the
274                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
275                  * to which we now hold a reference, or it is NULL.
276                  * We can't put it here under mq_lock, though.
277                  */
278                 if (ipc_ns)
279                         ipc_ns->mq_queues_count--;
280                 spin_unlock(&mq_lock);
281                 free_uid(user);
282         }
283         if (ipc_ns)
284                 put_ipc_ns(ipc_ns);
285 }
286
287 static int mqueue_create(struct inode *dir, struct dentry *dentry,
288                                 umode_t mode, struct nameidata *nd)
289 {
290         struct inode *inode;
291         struct mq_attr *attr = dentry->d_fsdata;
292         int error;
293         struct ipc_namespace *ipc_ns;
294
295         spin_lock(&mq_lock);
296         ipc_ns = __get_ns_from_inode(dir);
297         if (!ipc_ns) {
298                 error = -EACCES;
299                 goto out_unlock;
300         }
301         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
302                         !capable(CAP_SYS_RESOURCE)) {
303                 error = -ENOSPC;
304                 goto out_unlock;
305         }
306         ipc_ns->mq_queues_count++;
307         spin_unlock(&mq_lock);
308
309         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
310         if (IS_ERR(inode)) {
311                 error = PTR_ERR(inode);
312                 spin_lock(&mq_lock);
313                 ipc_ns->mq_queues_count--;
314                 goto out_unlock;
315         }
316
317         put_ipc_ns(ipc_ns);
318         dir->i_size += DIRENT_SIZE;
319         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
320
321         d_instantiate(dentry, inode);
322         dget(dentry);
323         return 0;
324 out_unlock:
325         spin_unlock(&mq_lock);
326         if (ipc_ns)
327                 put_ipc_ns(ipc_ns);
328         return error;
329 }
330
331 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
332 {
333         struct inode *inode = dentry->d_inode;
334
335         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
336         dir->i_size -= DIRENT_SIZE;
337         drop_nlink(inode);
338         dput(dentry);
339         return 0;
340 }
341
342 /*
343 *       This is routine for system read from queue file.
344 *       To avoid mess with doing here some sort of mq_receive we allow
345 *       to read only queue size & notification info (the only values
346 *       that are interesting from user point of view and aren't accessible
347 *       through std routines)
348 */
349 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
350                                 size_t count, loff_t *off)
351 {
352         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
353         char buffer[FILENT_SIZE];
354         ssize_t ret;
355
356         spin_lock(&info->lock);
357         snprintf(buffer, sizeof(buffer),
358                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
359                         info->qsize,
360                         info->notify_owner ? info->notify.sigev_notify : 0,
361                         (info->notify_owner &&
362                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
363                                 info->notify.sigev_signo : 0,
364                         pid_vnr(info->notify_owner));
365         spin_unlock(&info->lock);
366         buffer[sizeof(buffer)-1] = '\0';
367
368         ret = simple_read_from_buffer(u_data, count, off, buffer,
369                                 strlen(buffer));
370         if (ret <= 0)
371                 return ret;
372
373         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
374         return ret;
375 }
376
377 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
378 {
379         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
380
381         spin_lock(&info->lock);
382         if (task_tgid(current) == info->notify_owner)
383                 remove_notification(info);
384
385         spin_unlock(&info->lock);
386         return 0;
387 }
388
389 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
390 {
391         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
392         int retval = 0;
393
394         poll_wait(filp, &info->wait_q, poll_tab);
395
396         spin_lock(&info->lock);
397         if (info->attr.mq_curmsgs)
398                 retval = POLLIN | POLLRDNORM;
399
400         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
401                 retval |= POLLOUT | POLLWRNORM;
402         spin_unlock(&info->lock);
403
404         return retval;
405 }
406
407 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
408 static void wq_add(struct mqueue_inode_info *info, int sr,
409                         struct ext_wait_queue *ewp)
410 {
411         struct ext_wait_queue *walk;
412
413         ewp->task = current;
414
415         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
416                 if (walk->task->static_prio <= current->static_prio) {
417                         list_add_tail(&ewp->list, &walk->list);
418                         return;
419                 }
420         }
421         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
422 }
423
424 /*
425  * Puts current task to sleep. Caller must hold queue lock. After return
426  * lock isn't held.
427  * sr: SEND or RECV
428  */
429 static int wq_sleep(struct mqueue_inode_info *info, int sr,
430                     ktime_t *timeout, struct ext_wait_queue *ewp)
431 {
432         int retval;
433         signed long time;
434
435         wq_add(info, sr, ewp);
436
437         for (;;) {
438                 set_current_state(TASK_INTERRUPTIBLE);
439
440                 spin_unlock(&info->lock);
441                 time = schedule_hrtimeout_range_clock(timeout, 0,
442                         HRTIMER_MODE_ABS, CLOCK_REALTIME);
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                         /* map current pid/uid into info->owner's namespaces */
536                         rcu_read_lock();
537                         sig_i.si_pid = task_tgid_nr_ns(current,
538                                                 ns_of_pid(info->notify_owner));
539                         sig_i.si_uid = user_ns_map_uid(info->user->user_ns,
540                                                 current_cred(), current_uid());
541                         rcu_read_unlock();
542
543                         kill_pid_info(info->notify.sigev_signo,
544                                       &sig_i, info->notify_owner);
545                         break;
546                 case SIGEV_THREAD:
547                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
548                         netlink_sendskb(info->notify_sock, info->notify_cookie);
549                         break;
550                 }
551                 /* after notification unregisters process */
552                 put_pid(info->notify_owner);
553                 info->notify_owner = NULL;
554         }
555         wake_up(&info->wait_q);
556 }
557
558 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
559                            ktime_t *expires, struct timespec *ts)
560 {
561         if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
562                 return -EFAULT;
563         if (!timespec_valid(ts))
564                 return -EINVAL;
565
566         *expires = timespec_to_ktime(*ts);
567         return 0;
568 }
569
570 static void remove_notification(struct mqueue_inode_info *info)
571 {
572         if (info->notify_owner != NULL &&
573             info->notify.sigev_notify == SIGEV_THREAD) {
574                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
575                 netlink_sendskb(info->notify_sock, info->notify_cookie);
576         }
577         put_pid(info->notify_owner);
578         info->notify_owner = NULL;
579 }
580
581 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
582 {
583         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
584                 return 0;
585         if (capable(CAP_SYS_RESOURCE)) {
586                 if (attr->mq_maxmsg > HARD_MSGMAX)
587                         return 0;
588         } else {
589                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
590                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
591                         return 0;
592         }
593         /* check for overflow */
594         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
595                 return 0;
596         if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
597             + sizeof (struct msg_msg *))) <
598             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
599                 return 0;
600         return 1;
601 }
602
603 /*
604  * Invoked when creating a new queue via sys_mq_open
605  */
606 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
607                         struct dentry *dentry, int oflag, umode_t mode,
608                         struct mq_attr *attr)
609 {
610         const struct cred *cred = current_cred();
611         struct file *result;
612         int ret;
613
614         if (attr) {
615                 if (!mq_attr_ok(ipc_ns, attr)) {
616                         ret = -EINVAL;
617                         goto out;
618                 }
619                 /* store for use during create */
620                 dentry->d_fsdata = attr;
621         }
622
623         mode &= ~current_umask();
624         ret = mnt_want_write(ipc_ns->mq_mnt);
625         if (ret)
626                 goto out;
627         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
628         dentry->d_fsdata = NULL;
629         if (ret)
630                 goto out_drop_write;
631
632         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
633         /*
634          * dentry_open() took a persistent mnt_want_write(),
635          * so we can now drop this one.
636          */
637         mnt_drop_write(ipc_ns->mq_mnt);
638         return result;
639
640 out_drop_write:
641         mnt_drop_write(ipc_ns->mq_mnt);
642 out:
643         dput(dentry);
644         mntput(ipc_ns->mq_mnt);
645         return ERR_PTR(ret);
646 }
647
648 /* Opens existing queue */
649 static struct file *do_open(struct ipc_namespace *ipc_ns,
650                                 struct dentry *dentry, int oflag)
651 {
652         int ret;
653         const struct cred *cred = current_cred();
654
655         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
656                                                   MAY_READ | MAY_WRITE };
657
658         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
659                 ret = -EINVAL;
660                 goto err;
661         }
662
663         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
664                 ret = -EACCES;
665                 goto err;
666         }
667
668         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
669
670 err:
671         dput(dentry);
672         mntput(ipc_ns->mq_mnt);
673         return ERR_PTR(ret);
674 }
675
676 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
677                 struct mq_attr __user *, u_attr)
678 {
679         struct dentry *dentry;
680         struct file *filp;
681         char *name;
682         struct mq_attr attr;
683         int fd, error;
684         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
685
686         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
687                 return -EFAULT;
688
689         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
690
691         if (IS_ERR(name = getname(u_name)))
692                 return PTR_ERR(name);
693
694         fd = get_unused_fd_flags(O_CLOEXEC);
695         if (fd < 0)
696                 goto out_putname;
697
698         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
699         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
700         if (IS_ERR(dentry)) {
701                 error = PTR_ERR(dentry);
702                 goto out_putfd;
703         }
704         mntget(ipc_ns->mq_mnt);
705
706         if (oflag & O_CREAT) {
707                 if (dentry->d_inode) {  /* entry already exists */
708                         audit_inode(name, dentry);
709                         if (oflag & O_EXCL) {
710                                 error = -EEXIST;
711                                 goto out;
712                         }
713                         filp = do_open(ipc_ns, dentry, oflag);
714                 } else {
715                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
716                                                 dentry, oflag, mode,
717                                                 u_attr ? &attr : NULL);
718                 }
719         } else {
720                 if (!dentry->d_inode) {
721                         error = -ENOENT;
722                         goto out;
723                 }
724                 audit_inode(name, dentry);
725                 filp = do_open(ipc_ns, dentry, oflag);
726         }
727
728         if (IS_ERR(filp)) {
729                 error = PTR_ERR(filp);
730                 goto out_putfd;
731         }
732
733         fd_install(fd, filp);
734         goto out_upsem;
735
736 out:
737         dput(dentry);
738         mntput(ipc_ns->mq_mnt);
739 out_putfd:
740         put_unused_fd(fd);
741         fd = error;
742 out_upsem:
743         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
744 out_putname:
745         putname(name);
746         return fd;
747 }
748
749 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
750 {
751         int err;
752         char *name;
753         struct dentry *dentry;
754         struct inode *inode = NULL;
755         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
756
757         name = getname(u_name);
758         if (IS_ERR(name))
759                 return PTR_ERR(name);
760
761         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
762                         I_MUTEX_PARENT);
763         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
764         if (IS_ERR(dentry)) {
765                 err = PTR_ERR(dentry);
766                 goto out_unlock;
767         }
768
769         if (!dentry->d_inode) {
770                 err = -ENOENT;
771                 goto out_err;
772         }
773
774         inode = dentry->d_inode;
775         if (inode)
776                 ihold(inode);
777         err = mnt_want_write(ipc_ns->mq_mnt);
778         if (err)
779                 goto out_err;
780         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
781         mnt_drop_write(ipc_ns->mq_mnt);
782 out_err:
783         dput(dentry);
784
785 out_unlock:
786         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
787         putname(name);
788         if (inode)
789                 iput(inode);
790
791         return err;
792 }
793
794 /* Pipelined send and receive functions.
795  *
796  * If a receiver finds no waiting message, then it registers itself in the
797  * list of waiting receivers. A sender checks that list before adding the new
798  * message into the message array. If there is a waiting receiver, then it
799  * bypasses the message array and directly hands the message over to the
800  * receiver.
801  * The receiver accepts the message and returns without grabbing the queue
802  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
803  * are necessary. The same algorithm is used for sysv semaphores, see
804  * ipc/sem.c for more details.
805  *
806  * The same algorithm is used for senders.
807  */
808
809 /* pipelined_send() - send a message directly to the task waiting in
810  * sys_mq_timedreceive() (without inserting message into a queue).
811  */
812 static inline void pipelined_send(struct mqueue_inode_info *info,
813                                   struct msg_msg *message,
814                                   struct ext_wait_queue *receiver)
815 {
816         receiver->msg = message;
817         list_del(&receiver->list);
818         receiver->state = STATE_PENDING;
819         wake_up_process(receiver->task);
820         smp_wmb();
821         receiver->state = STATE_READY;
822 }
823
824 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
825  * gets its message and put to the queue (we have one free place for sure). */
826 static inline void pipelined_receive(struct mqueue_inode_info *info)
827 {
828         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
829
830         if (!sender) {
831                 /* for poll */
832                 wake_up_interruptible(&info->wait_q);
833                 return;
834         }
835         msg_insert(sender->msg, info);
836         list_del(&sender->list);
837         sender->state = STATE_PENDING;
838         wake_up_process(sender->task);
839         smp_wmb();
840         sender->state = STATE_READY;
841 }
842
843 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
844                 size_t, msg_len, unsigned int, msg_prio,
845                 const struct timespec __user *, u_abs_timeout)
846 {
847         struct file *filp;
848         struct inode *inode;
849         struct ext_wait_queue wait;
850         struct ext_wait_queue *receiver;
851         struct msg_msg *msg_ptr;
852         struct mqueue_inode_info *info;
853         ktime_t expires, *timeout = NULL;
854         struct timespec ts;
855         int ret;
856
857         if (u_abs_timeout) {
858                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
859                 if (res)
860                         return res;
861                 timeout = &expires;
862         }
863
864         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
865                 return -EINVAL;
866
867         audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
868
869         filp = fget(mqdes);
870         if (unlikely(!filp)) {
871                 ret = -EBADF;
872                 goto out;
873         }
874
875         inode = filp->f_path.dentry->d_inode;
876         if (unlikely(filp->f_op != &mqueue_file_operations)) {
877                 ret = -EBADF;
878                 goto out_fput;
879         }
880         info = MQUEUE_I(inode);
881         audit_inode(NULL, filp->f_path.dentry);
882
883         if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
884                 ret = -EBADF;
885                 goto out_fput;
886         }
887
888         if (unlikely(msg_len > info->attr.mq_msgsize)) {
889                 ret = -EMSGSIZE;
890                 goto out_fput;
891         }
892
893         /* First try to allocate memory, before doing anything with
894          * existing queues. */
895         msg_ptr = load_msg(u_msg_ptr, msg_len);
896         if (IS_ERR(msg_ptr)) {
897                 ret = PTR_ERR(msg_ptr);
898                 goto out_fput;
899         }
900         msg_ptr->m_ts = msg_len;
901         msg_ptr->m_type = msg_prio;
902
903         spin_lock(&info->lock);
904
905         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
906                 if (filp->f_flags & O_NONBLOCK) {
907                         spin_unlock(&info->lock);
908                         ret = -EAGAIN;
909                 } else {
910                         wait.task = current;
911                         wait.msg = (void *) msg_ptr;
912                         wait.state = STATE_NONE;
913                         ret = wq_sleep(info, SEND, timeout, &wait);
914                 }
915                 if (ret < 0)
916                         free_msg(msg_ptr);
917         } else {
918                 receiver = wq_get_first_waiter(info, RECV);
919                 if (receiver) {
920                         pipelined_send(info, msg_ptr, receiver);
921                 } else {
922                         /* adds message to the queue */
923                         msg_insert(msg_ptr, info);
924                         __do_notify(info);
925                 }
926                 inode->i_atime = inode->i_mtime = inode->i_ctime =
927                                 CURRENT_TIME;
928                 spin_unlock(&info->lock);
929                 ret = 0;
930         }
931 out_fput:
932         fput(filp);
933 out:
934         return ret;
935 }
936
937 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
938                 size_t, msg_len, unsigned int __user *, u_msg_prio,
939                 const struct timespec __user *, u_abs_timeout)
940 {
941         ssize_t ret;
942         struct msg_msg *msg_ptr;
943         struct file *filp;
944         struct inode *inode;
945         struct mqueue_inode_info *info;
946         struct ext_wait_queue wait;
947         ktime_t expires, *timeout = NULL;
948         struct timespec ts;
949
950         if (u_abs_timeout) {
951                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
952                 if (res)
953                         return res;
954                 timeout = &expires;
955         }
956
957         audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
958
959         filp = fget(mqdes);
960         if (unlikely(!filp)) {
961                 ret = -EBADF;
962                 goto out;
963         }
964
965         inode = filp->f_path.dentry->d_inode;
966         if (unlikely(filp->f_op != &mqueue_file_operations)) {
967                 ret = -EBADF;
968                 goto out_fput;
969         }
970         info = MQUEUE_I(inode);
971         audit_inode(NULL, filp->f_path.dentry);
972
973         if (unlikely(!(filp->f_mode & FMODE_READ))) {
974                 ret = -EBADF;
975                 goto out_fput;
976         }
977
978         /* checks if buffer is big enough */
979         if (unlikely(msg_len < info->attr.mq_msgsize)) {
980                 ret = -EMSGSIZE;
981                 goto out_fput;
982         }
983
984         spin_lock(&info->lock);
985         if (info->attr.mq_curmsgs == 0) {
986                 if (filp->f_flags & O_NONBLOCK) {
987                         spin_unlock(&info->lock);
988                         ret = -EAGAIN;
989                 } else {
990                         wait.task = current;
991                         wait.state = STATE_NONE;
992                         ret = wq_sleep(info, RECV, timeout, &wait);
993                         msg_ptr = wait.msg;
994                 }
995         } else {
996                 msg_ptr = msg_get(info);
997
998                 inode->i_atime = inode->i_mtime = inode->i_ctime =
999                                 CURRENT_TIME;
1000
1001                 /* There is now free space in queue. */
1002                 pipelined_receive(info);
1003                 spin_unlock(&info->lock);
1004                 ret = 0;
1005         }
1006         if (ret == 0) {
1007                 ret = msg_ptr->m_ts;
1008
1009                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1010                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1011                         ret = -EFAULT;
1012                 }
1013                 free_msg(msg_ptr);
1014         }
1015 out_fput:
1016         fput(filp);
1017 out:
1018         return ret;
1019 }
1020
1021 /*
1022  * Notes: the case when user wants us to deregister (with NULL as pointer)
1023  * and he isn't currently owner of notification, will be silently discarded.
1024  * It isn't explicitly defined in the POSIX.
1025  */
1026 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1027                 const struct sigevent __user *, u_notification)
1028 {
1029         int ret;
1030         struct file *filp;
1031         struct sock *sock;
1032         struct inode *inode;
1033         struct sigevent notification;
1034         struct mqueue_inode_info *info;
1035         struct sk_buff *nc;
1036
1037         if (u_notification) {
1038                 if (copy_from_user(&notification, u_notification,
1039                                         sizeof(struct sigevent)))
1040                         return -EFAULT;
1041         }
1042
1043         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1044
1045         nc = NULL;
1046         sock = NULL;
1047         if (u_notification != NULL) {
1048                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1049                              notification.sigev_notify != SIGEV_SIGNAL &&
1050                              notification.sigev_notify != SIGEV_THREAD))
1051                         return -EINVAL;
1052                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1053                         !valid_signal(notification.sigev_signo)) {
1054                         return -EINVAL;
1055                 }
1056                 if (notification.sigev_notify == SIGEV_THREAD) {
1057                         long timeo;
1058
1059                         /* create the notify skb */
1060                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1061                         if (!nc) {
1062                                 ret = -ENOMEM;
1063                                 goto out;
1064                         }
1065                         if (copy_from_user(nc->data,
1066                                         notification.sigev_value.sival_ptr,
1067                                         NOTIFY_COOKIE_LEN)) {
1068                                 ret = -EFAULT;
1069                                 goto out;
1070                         }
1071
1072                         /* TODO: add a header? */
1073                         skb_put(nc, NOTIFY_COOKIE_LEN);
1074                         /* and attach it to the socket */
1075 retry:
1076                         filp = fget(notification.sigev_signo);
1077                         if (!filp) {
1078                                 ret = -EBADF;
1079                                 goto out;
1080                         }
1081                         sock = netlink_getsockbyfilp(filp);
1082                         fput(filp);
1083                         if (IS_ERR(sock)) {
1084                                 ret = PTR_ERR(sock);
1085                                 sock = NULL;
1086                                 goto out;
1087                         }
1088
1089                         timeo = MAX_SCHEDULE_TIMEOUT;
1090                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1091                         if (ret == 1)
1092                                 goto retry;
1093                         if (ret) {
1094                                 sock = NULL;
1095                                 nc = NULL;
1096                                 goto out;
1097                         }
1098                 }
1099         }
1100
1101         filp = fget(mqdes);
1102         if (!filp) {
1103                 ret = -EBADF;
1104                 goto out;
1105         }
1106
1107         inode = filp->f_path.dentry->d_inode;
1108         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1109                 ret = -EBADF;
1110                 goto out_fput;
1111         }
1112         info = MQUEUE_I(inode);
1113
1114         ret = 0;
1115         spin_lock(&info->lock);
1116         if (u_notification == NULL) {
1117                 if (info->notify_owner == task_tgid(current)) {
1118                         remove_notification(info);
1119                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1120                 }
1121         } else if (info->notify_owner != NULL) {
1122                 ret = -EBUSY;
1123         } else {
1124                 switch (notification.sigev_notify) {
1125                 case SIGEV_NONE:
1126                         info->notify.sigev_notify = SIGEV_NONE;
1127                         break;
1128                 case SIGEV_THREAD:
1129                         info->notify_sock = sock;
1130                         info->notify_cookie = nc;
1131                         sock = NULL;
1132                         nc = NULL;
1133                         info->notify.sigev_notify = SIGEV_THREAD;
1134                         break;
1135                 case SIGEV_SIGNAL:
1136                         info->notify.sigev_signo = notification.sigev_signo;
1137                         info->notify.sigev_value = notification.sigev_value;
1138                         info->notify.sigev_notify = SIGEV_SIGNAL;
1139                         break;
1140                 }
1141
1142                 info->notify_owner = get_pid(task_tgid(current));
1143                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1144         }
1145         spin_unlock(&info->lock);
1146 out_fput:
1147         fput(filp);
1148 out:
1149         if (sock) {
1150                 netlink_detachskb(sock, nc);
1151         } else if (nc) {
1152                 dev_kfree_skb(nc);
1153         }
1154         return ret;
1155 }
1156
1157 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1158                 const struct mq_attr __user *, u_mqstat,
1159                 struct mq_attr __user *, u_omqstat)
1160 {
1161         int ret;
1162         struct mq_attr mqstat, omqstat;
1163         struct file *filp;
1164         struct inode *inode;
1165         struct mqueue_inode_info *info;
1166
1167         if (u_mqstat != NULL) {
1168                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1169                         return -EFAULT;
1170                 if (mqstat.mq_flags & (~O_NONBLOCK))
1171                         return -EINVAL;
1172         }
1173
1174         filp = fget(mqdes);
1175         if (!filp) {
1176                 ret = -EBADF;
1177                 goto out;
1178         }
1179
1180         inode = filp->f_path.dentry->d_inode;
1181         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1182                 ret = -EBADF;
1183                 goto out_fput;
1184         }
1185         info = MQUEUE_I(inode);
1186
1187         spin_lock(&info->lock);
1188
1189         omqstat = info->attr;
1190         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1191         if (u_mqstat) {
1192                 audit_mq_getsetattr(mqdes, &mqstat);
1193                 spin_lock(&filp->f_lock);
1194                 if (mqstat.mq_flags & O_NONBLOCK)
1195                         filp->f_flags |= O_NONBLOCK;
1196                 else
1197                         filp->f_flags &= ~O_NONBLOCK;
1198                 spin_unlock(&filp->f_lock);
1199
1200                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1201         }
1202
1203         spin_unlock(&info->lock);
1204
1205         ret = 0;
1206         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1207                                                 sizeof(struct mq_attr)))
1208                 ret = -EFAULT;
1209
1210 out_fput:
1211         fput(filp);
1212 out:
1213         return ret;
1214 }
1215
1216 static const struct inode_operations mqueue_dir_inode_operations = {
1217         .lookup = simple_lookup,
1218         .create = mqueue_create,
1219         .unlink = mqueue_unlink,
1220 };
1221
1222 static const struct file_operations mqueue_file_operations = {
1223         .flush = mqueue_flush_file,
1224         .poll = mqueue_poll_file,
1225         .read = mqueue_read_file,
1226         .llseek = default_llseek,
1227 };
1228
1229 static const struct super_operations mqueue_super_ops = {
1230         .alloc_inode = mqueue_alloc_inode,
1231         .destroy_inode = mqueue_destroy_inode,
1232         .evict_inode = mqueue_evict_inode,
1233         .statfs = simple_statfs,
1234 };
1235
1236 static struct file_system_type mqueue_fs_type = {
1237         .name = "mqueue",
1238         .mount = mqueue_mount,
1239         .kill_sb = kill_litter_super,
1240 };
1241
1242 int mq_init_ns(struct ipc_namespace *ns)
1243 {
1244         ns->mq_queues_count  = 0;
1245         ns->mq_queues_max    = DFLT_QUEUESMAX;
1246         ns->mq_msg_max       = DFLT_MSGMAX;
1247         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1248
1249         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1250         if (IS_ERR(ns->mq_mnt)) {
1251                 int err = PTR_ERR(ns->mq_mnt);
1252                 ns->mq_mnt = NULL;
1253                 return err;
1254         }
1255         return 0;
1256 }
1257
1258 void mq_clear_sbinfo(struct ipc_namespace *ns)
1259 {
1260         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1261 }
1262
1263 void mq_put_mnt(struct ipc_namespace *ns)
1264 {
1265         kern_unmount(ns->mq_mnt);
1266 }
1267
1268 static int __init init_mqueue_fs(void)
1269 {
1270         int error;
1271
1272         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1273                                 sizeof(struct mqueue_inode_info), 0,
1274                                 SLAB_HWCACHE_ALIGN, init_once);
1275         if (mqueue_inode_cachep == NULL)
1276                 return -ENOMEM;
1277
1278         /* ignore failures - they are not fatal */
1279         mq_sysctl_table = mq_register_sysctl_table();
1280
1281         error = register_filesystem(&mqueue_fs_type);
1282         if (error)
1283                 goto out_sysctl;
1284
1285         spin_lock_init(&mq_lock);
1286
1287         error = mq_init_ns(&init_ipc_ns);
1288         if (error)
1289                 goto out_filesystem;
1290
1291         return 0;
1292
1293 out_filesystem:
1294         unregister_filesystem(&mqueue_fs_type);
1295 out_sysctl:
1296         if (mq_sysctl_table)
1297                 unregister_sysctl_table(mq_sysctl_table);
1298         kmem_cache_destroy(mqueue_inode_cachep);
1299         return error;
1300 }
1301
1302 __initcall(init_mqueue_fs);