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