namespaces: ipc namespaces: implement support for posix msqueues
[linux-2.6.git] / ipc / mqueue.c
1 /*
2  * POSIX message queues filesystem for Linux.
3  *
4  * Copyright (C) 2003,2004  Krzysztof Benedyczak    (golbi@mat.uni.torun.pl)
5  *                          Michal Wronski          (michal.wronski@gmail.com)
6  *
7  * Spinlocks:               Mohamed Abbas           (abbas.mohamed@intel.com)
8  * Lockless receive & send, fd based notify:
9  *                          Manfred Spraul          (manfred@colorfullife.com)
10  *
11  * Audit:                   George Wilson           (ltcgcw@us.ibm.com)
12  *
13  * This file is released under the GPL.
14  */
15
16 #include <linux/capability.h>
17 #include <linux/init.h>
18 #include <linux/pagemap.h>
19 #include <linux/file.h>
20 #include <linux/mount.h>
21 #include <linux/namei.h>
22 #include <linux/sysctl.h>
23 #include <linux/poll.h>
24 #include <linux/mqueue.h>
25 #include <linux/msg.h>
26 #include <linux/skbuff.h>
27 #include <linux/netlink.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/signal.h>
31 #include <linux/mutex.h>
32 #include <linux/nsproxy.h>
33 #include <linux/pid.h>
34 #include <linux/ipc_namespace.h>
35
36 #include <net/sock.h>
37 #include "util.h"
38
39 #define MQUEUE_MAGIC    0x19800202
40 #define DIRENT_SIZE     20
41 #define FILENT_SIZE     80
42
43 #define SEND            0
44 #define RECV            1
45
46 #define STATE_NONE      0
47 #define STATE_PENDING   1
48 #define STATE_READY     2
49
50 /*
51  * Define the ranges various user-specified maximum values can
52  * be set to.
53  */
54 #define MIN_MSGMAX      1               /* min value for msg_max */
55 #define MAX_MSGMAX      HARD_MSGMAX     /* max value for msg_max */
56 #define MIN_MSGSIZEMAX  128             /* min value for msgsize_max */
57 #define MAX_MSGSIZEMAX  (8192*128)      /* max value for msgsize_max */
58
59 struct ext_wait_queue {         /* queue of sleeping tasks */
60         struct task_struct *task;
61         struct list_head list;
62         struct msg_msg *msg;    /* ptr of loaded message */
63         int state;              /* one of STATE_* values */
64 };
65
66 struct mqueue_inode_info {
67         spinlock_t lock;
68         struct inode vfs_inode;
69         wait_queue_head_t wait_q;
70
71         struct msg_msg **messages;
72         struct mq_attr attr;
73
74         struct sigevent notify;
75         struct pid* notify_owner;
76         struct user_struct *user;       /* user who created, for accounting */
77         struct sock *notify_sock;
78         struct sk_buff *notify_cookie;
79
80         /* for tasks waiting for free space and messages, respectively */
81         struct ext_wait_queue e_wait_q[2];
82
83         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
84 };
85
86 static const struct inode_operations mqueue_dir_inode_operations;
87 static const struct file_operations mqueue_file_operations;
88 static struct super_operations mqueue_super_ops;
89 static void remove_notification(struct mqueue_inode_info *info);
90
91 static struct kmem_cache *mqueue_inode_cachep;
92
93 static struct ctl_table_header * mq_sysctl_table;
94
95 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
96 {
97         return container_of(inode, struct mqueue_inode_info, vfs_inode);
98 }
99
100 /*
101  * This routine should be called with the mq_lock held.
102  */
103 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
104 {
105         return get_ipc_ns(inode->i_sb->s_fs_info);
106 }
107
108 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
109 {
110         struct ipc_namespace *ns;
111
112         spin_lock(&mq_lock);
113         ns = __get_ns_from_inode(inode);
114         spin_unlock(&mq_lock);
115         return ns;
116 }
117
118 static struct inode *mqueue_get_inode(struct super_block *sb,
119                 struct ipc_namespace *ipc_ns, int mode,
120                 struct mq_attr *attr)
121 {
122         struct user_struct *u = current_user();
123         struct inode *inode;
124
125         inode = new_inode(sb);
126         if (inode) {
127                 inode->i_mode = mode;
128                 inode->i_uid = current_fsuid();
129                 inode->i_gid = current_fsgid();
130                 inode->i_mtime = inode->i_ctime = inode->i_atime =
131                                 CURRENT_TIME;
132
133                 if (S_ISREG(mode)) {
134                         struct mqueue_inode_info *info;
135                         struct task_struct *p = current;
136                         unsigned long mq_bytes, mq_msg_tblsz;
137
138                         inode->i_fop = &mqueue_file_operations;
139                         inode->i_size = FILENT_SIZE;
140                         /* mqueue specific info */
141                         info = MQUEUE_I(inode);
142                         spin_lock_init(&info->lock);
143                         init_waitqueue_head(&info->wait_q);
144                         INIT_LIST_HEAD(&info->e_wait_q[0].list);
145                         INIT_LIST_HEAD(&info->e_wait_q[1].list);
146                         info->messages = NULL;
147                         info->notify_owner = NULL;
148                         info->qsize = 0;
149                         info->user = NULL;      /* set when all is ok */
150                         memset(&info->attr, 0, sizeof(info->attr));
151                         info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
152                         info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
153                         if (attr) {
154                                 info->attr.mq_maxmsg = attr->mq_maxmsg;
155                                 info->attr.mq_msgsize = attr->mq_msgsize;
156                         }
157                         mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
158                         mq_bytes = (mq_msg_tblsz +
159                                 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
160
161                         spin_lock(&mq_lock);
162                         if (u->mq_bytes + mq_bytes < u->mq_bytes ||
163                             u->mq_bytes + mq_bytes >
164                             p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
165                                 spin_unlock(&mq_lock);
166                                 goto out_inode;
167                         }
168                         u->mq_bytes += mq_bytes;
169                         spin_unlock(&mq_lock);
170
171                         info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
172                         if (!info->messages) {
173                                 spin_lock(&mq_lock);
174                                 u->mq_bytes -= mq_bytes;
175                                 spin_unlock(&mq_lock);
176                                 goto out_inode;
177                         }
178                         /* all is ok */
179                         info->user = get_uid(u);
180                 } else if (S_ISDIR(mode)) {
181                         inc_nlink(inode);
182                         /* Some things misbehave if size == 0 on a directory */
183                         inode->i_size = 2 * DIRENT_SIZE;
184                         inode->i_op = &mqueue_dir_inode_operations;
185                         inode->i_fop = &simple_dir_operations;
186                 }
187         }
188         return inode;
189 out_inode:
190         make_bad_inode(inode);
191         iput(inode);
192         return NULL;
193 }
194
195 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
196 {
197         struct inode *inode;
198         struct ipc_namespace *ns = data;
199         int error = 0;
200
201         sb->s_blocksize = PAGE_CACHE_SIZE;
202         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
203         sb->s_magic = MQUEUE_MAGIC;
204         sb->s_op = &mqueue_super_ops;
205
206         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
207                                 NULL);
208         if (!inode) {
209                 error = -ENOMEM;
210                 goto out;
211         }
212
213         sb->s_root = d_alloc_root(inode);
214         if (!sb->s_root) {
215                 iput(inode);
216                 error = -ENOMEM;
217         }
218
219 out:
220         return error;
221 }
222
223 static int mqueue_get_sb(struct file_system_type *fs_type,
224                          int flags, const char *dev_name,
225                          void *data, struct vfsmount *mnt)
226 {
227         if (!(flags & MS_KERNMOUNT))
228                 data = current->nsproxy->ipc_ns;
229         return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);
230 }
231
232 static void init_once(void *foo)
233 {
234         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
235
236         inode_init_once(&p->vfs_inode);
237 }
238
239 static struct inode *mqueue_alloc_inode(struct super_block *sb)
240 {
241         struct mqueue_inode_info *ei;
242
243         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
244         if (!ei)
245                 return NULL;
246         return &ei->vfs_inode;
247 }
248
249 static void mqueue_destroy_inode(struct inode *inode)
250 {
251         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
252 }
253
254 static void mqueue_delete_inode(struct inode *inode)
255 {
256         struct mqueue_inode_info *info;
257         struct user_struct *user;
258         unsigned long mq_bytes;
259         int i;
260         struct ipc_namespace *ipc_ns;
261
262         if (S_ISDIR(inode->i_mode)) {
263                 clear_inode(inode);
264                 return;
265         }
266         ipc_ns = get_ns_from_inode(inode);
267         info = MQUEUE_I(inode);
268         spin_lock(&info->lock);
269         for (i = 0; i < info->attr.mq_curmsgs; i++)
270                 free_msg(info->messages[i]);
271         kfree(info->messages);
272         spin_unlock(&info->lock);
273
274         clear_inode(inode);
275
276         mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
277                    (info->attr.mq_maxmsg * info->attr.mq_msgsize));
278         user = info->user;
279         if (user) {
280                 spin_lock(&mq_lock);
281                 user->mq_bytes -= mq_bytes;
282                 /*
283                  * get_ns_from_inode() ensures that the
284                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
285                  * to which we now hold a reference, or it is NULL.
286                  * We can't put it here under mq_lock, though.
287                  */
288                 if (ipc_ns)
289                         ipc_ns->mq_queues_count--;
290                 spin_unlock(&mq_lock);
291                 free_uid(user);
292         }
293         if (ipc_ns)
294                 put_ipc_ns(ipc_ns);
295 }
296
297 static int mqueue_create(struct inode *dir, struct dentry *dentry,
298                                 int mode, struct nameidata *nd)
299 {
300         struct inode *inode;
301         struct mq_attr *attr = dentry->d_fsdata;
302         int error;
303         struct ipc_namespace *ipc_ns;
304
305         spin_lock(&mq_lock);
306         ipc_ns = __get_ns_from_inode(dir);
307         if (!ipc_ns) {
308                 error = -EACCES;
309                 goto out_unlock;
310         }
311         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
312                         !capable(CAP_SYS_RESOURCE)) {
313                 error = -ENOSPC;
314                 goto out_unlock;
315         }
316         ipc_ns->mq_queues_count++;
317         spin_unlock(&mq_lock);
318
319         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
320         if (!inode) {
321                 error = -ENOMEM;
322                 spin_lock(&mq_lock);
323                 ipc_ns->mq_queues_count--;
324                 goto out_unlock;
325         }
326
327         put_ipc_ns(ipc_ns);
328         dir->i_size += DIRENT_SIZE;
329         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
330
331         d_instantiate(dentry, inode);
332         dget(dentry);
333         return 0;
334 out_unlock:
335         spin_unlock(&mq_lock);
336         if (ipc_ns)
337                 put_ipc_ns(ipc_ns);
338         return error;
339 }
340
341 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
342 {
343         struct inode *inode = dentry->d_inode;
344
345         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
346         dir->i_size -= DIRENT_SIZE;
347         drop_nlink(inode);
348         dput(dentry);
349         return 0;
350 }
351
352 /*
353 *       This is routine for system read from queue file.
354 *       To avoid mess with doing here some sort of mq_receive we allow
355 *       to read only queue size & notification info (the only values
356 *       that are interesting from user point of view and aren't accessible
357 *       through std routines)
358 */
359 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
360                                 size_t count, loff_t *off)
361 {
362         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
363         char buffer[FILENT_SIZE];
364         ssize_t ret;
365
366         spin_lock(&info->lock);
367         snprintf(buffer, sizeof(buffer),
368                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
369                         info->qsize,
370                         info->notify_owner ? info->notify.sigev_notify : 0,
371                         (info->notify_owner &&
372                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
373                                 info->notify.sigev_signo : 0,
374                         pid_vnr(info->notify_owner));
375         spin_unlock(&info->lock);
376         buffer[sizeof(buffer)-1] = '\0';
377
378         ret = simple_read_from_buffer(u_data, count, off, buffer,
379                                 strlen(buffer));
380         if (ret <= 0)
381                 return ret;
382
383         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
384         return ret;
385 }
386
387 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
388 {
389         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
390
391         spin_lock(&info->lock);
392         if (task_tgid(current) == info->notify_owner)
393                 remove_notification(info);
394
395         spin_unlock(&info->lock);
396         return 0;
397 }
398
399 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
400 {
401         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
402         int retval = 0;
403
404         poll_wait(filp, &info->wait_q, poll_tab);
405
406         spin_lock(&info->lock);
407         if (info->attr.mq_curmsgs)
408                 retval = POLLIN | POLLRDNORM;
409
410         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
411                 retval |= POLLOUT | POLLWRNORM;
412         spin_unlock(&info->lock);
413
414         return retval;
415 }
416
417 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
418 static void wq_add(struct mqueue_inode_info *info, int sr,
419                         struct ext_wait_queue *ewp)
420 {
421         struct ext_wait_queue *walk;
422
423         ewp->task = current;
424
425         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
426                 if (walk->task->static_prio <= current->static_prio) {
427                         list_add_tail(&ewp->list, &walk->list);
428                         return;
429                 }
430         }
431         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
432 }
433
434 /*
435  * Puts current task to sleep. Caller must hold queue lock. After return
436  * lock isn't held.
437  * sr: SEND or RECV
438  */
439 static int wq_sleep(struct mqueue_inode_info *info, int sr,
440                         long timeout, struct ext_wait_queue *ewp)
441 {
442         int retval;
443         signed long time;
444
445         wq_add(info, sr, ewp);
446
447         for (;;) {
448                 set_current_state(TASK_INTERRUPTIBLE);
449
450                 spin_unlock(&info->lock);
451                 time = schedule_timeout(timeout);
452
453                 while (ewp->state == STATE_PENDING)
454                         cpu_relax();
455
456                 if (ewp->state == STATE_READY) {
457                         retval = 0;
458                         goto out;
459                 }
460                 spin_lock(&info->lock);
461                 if (ewp->state == STATE_READY) {
462                         retval = 0;
463                         goto out_unlock;
464                 }
465                 if (signal_pending(current)) {
466                         retval = -ERESTARTSYS;
467                         break;
468                 }
469                 if (time == 0) {
470                         retval = -ETIMEDOUT;
471                         break;
472                 }
473         }
474         list_del(&ewp->list);
475 out_unlock:
476         spin_unlock(&info->lock);
477 out:
478         return retval;
479 }
480
481 /*
482  * Returns waiting task that should be serviced first or NULL if none exists
483  */
484 static struct ext_wait_queue *wq_get_first_waiter(
485                 struct mqueue_inode_info *info, int sr)
486 {
487         struct list_head *ptr;
488
489         ptr = info->e_wait_q[sr].list.prev;
490         if (ptr == &info->e_wait_q[sr].list)
491                 return NULL;
492         return list_entry(ptr, struct ext_wait_queue, list);
493 }
494
495 /* Auxiliary functions to manipulate messages' list */
496 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
497 {
498         int k;
499
500         k = info->attr.mq_curmsgs - 1;
501         while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
502                 info->messages[k + 1] = info->messages[k];
503                 k--;
504         }
505         info->attr.mq_curmsgs++;
506         info->qsize += ptr->m_ts;
507         info->messages[k + 1] = ptr;
508 }
509
510 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
511 {
512         info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
513         return info->messages[info->attr.mq_curmsgs];
514 }
515
516 static inline void set_cookie(struct sk_buff *skb, char code)
517 {
518         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
519 }
520
521 /*
522  * The next function is only to split too long sys_mq_timedsend
523  */
524 static void __do_notify(struct mqueue_inode_info *info)
525 {
526         /* notification
527          * invoked when there is registered process and there isn't process
528          * waiting synchronously for message AND state of queue changed from
529          * empty to not empty. Here we are sure that no one is waiting
530          * synchronously. */
531         if (info->notify_owner &&
532             info->attr.mq_curmsgs == 1) {
533                 struct siginfo sig_i;
534                 switch (info->notify.sigev_notify) {
535                 case SIGEV_NONE:
536                         break;
537                 case SIGEV_SIGNAL:
538                         /* sends signal */
539
540                         sig_i.si_signo = info->notify.sigev_signo;
541                         sig_i.si_errno = 0;
542                         sig_i.si_code = SI_MESGQ;
543                         sig_i.si_value = info->notify.sigev_value;
544                         sig_i.si_pid = task_tgid_nr_ns(current,
545                                                 ns_of_pid(info->notify_owner));
546                         sig_i.si_uid = current_uid();
547
548                         kill_pid_info(info->notify.sigev_signo,
549                                       &sig_i, info->notify_owner);
550                         break;
551                 case SIGEV_THREAD:
552                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
553                         netlink_sendskb(info->notify_sock, info->notify_cookie);
554                         break;
555                 }
556                 /* after notification unregisters process */
557                 put_pid(info->notify_owner);
558                 info->notify_owner = NULL;
559         }
560         wake_up(&info->wait_q);
561 }
562
563 static long prepare_timeout(struct timespec *p)
564 {
565         struct timespec nowts;
566         long timeout;
567
568         if (p) {
569                 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
570                         || p->tv_nsec >= NSEC_PER_SEC))
571                         return -EINVAL;
572                 nowts = CURRENT_TIME;
573                 /* first subtract as jiffies can't be too big */
574                 p->tv_sec -= nowts.tv_sec;
575                 if (p->tv_nsec < nowts.tv_nsec) {
576                         p->tv_nsec += NSEC_PER_SEC;
577                         p->tv_sec--;
578                 }
579                 p->tv_nsec -= nowts.tv_nsec;
580                 if (p->tv_sec < 0)
581                         return 0;
582
583                 timeout = timespec_to_jiffies(p) + 1;
584         } else
585                 return MAX_SCHEDULE_TIMEOUT;
586
587         return timeout;
588 }
589
590 static void remove_notification(struct mqueue_inode_info *info)
591 {
592         if (info->notify_owner != NULL &&
593             info->notify.sigev_notify == SIGEV_THREAD) {
594                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
595                 netlink_sendskb(info->notify_sock, info->notify_cookie);
596         }
597         put_pid(info->notify_owner);
598         info->notify_owner = NULL;
599 }
600
601 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
602 {
603         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
604                 return 0;
605         if (capable(CAP_SYS_RESOURCE)) {
606                 if (attr->mq_maxmsg > HARD_MSGMAX)
607                         return 0;
608         } else {
609                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
610                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
611                         return 0;
612         }
613         /* check for overflow */
614         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
615                 return 0;
616         if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
617             (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
618             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
619                 return 0;
620         return 1;
621 }
622
623 /*
624  * Invoked when creating a new queue via sys_mq_open
625  */
626 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
627                         struct dentry *dentry, int oflag, mode_t mode,
628                         struct mq_attr *attr)
629 {
630         const struct cred *cred = current_cred();
631         struct file *result;
632         int ret;
633
634         if (attr) {
635                 ret = -EINVAL;
636                 if (!mq_attr_ok(ipc_ns, attr))
637                         goto out;
638                 /* store for use during create */
639                 dentry->d_fsdata = attr;
640         }
641
642         mode &= ~current_umask();
643         ret = mnt_want_write(ipc_ns->mq_mnt);
644         if (ret)
645                 goto out;
646         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
647         dentry->d_fsdata = NULL;
648         if (ret)
649                 goto out_drop_write;
650
651         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
652         /*
653          * dentry_open() took a persistent mnt_want_write(),
654          * so we can now drop this one.
655          */
656         mnt_drop_write(ipc_ns->mq_mnt);
657         return result;
658
659 out_drop_write:
660         mnt_drop_write(ipc_ns->mq_mnt);
661 out:
662         dput(dentry);
663         mntput(ipc_ns->mq_mnt);
664         return ERR_PTR(ret);
665 }
666
667 /* Opens existing queue */
668 static struct file *do_open(struct ipc_namespace *ipc_ns,
669                                 struct dentry *dentry, int oflag)
670 {
671         const struct cred *cred = current_cred();
672
673         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
674                                                   MAY_READ | MAY_WRITE };
675
676         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
677                 dput(dentry);
678                 mntput(ipc_ns->mq_mnt);
679                 return ERR_PTR(-EINVAL);
680         }
681
682         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
683                 dput(dentry);
684                 mntput(ipc_ns->mq_mnt);
685                 return ERR_PTR(-EACCES);
686         }
687
688         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
689 }
690
691 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
692                 struct mq_attr __user *, u_attr)
693 {
694         struct dentry *dentry;
695         struct file *filp;
696         char *name;
697         struct mq_attr attr;
698         int fd, error;
699         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
700
701         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
702                 return -EFAULT;
703
704         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
705
706         if (IS_ERR(name = getname(u_name)))
707                 return PTR_ERR(name);
708
709         fd = get_unused_fd_flags(O_CLOEXEC);
710         if (fd < 0)
711                 goto out_putname;
712
713         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
714         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
715         if (IS_ERR(dentry)) {
716                 error = PTR_ERR(dentry);
717                 goto out_err;
718         }
719         mntget(ipc_ns->mq_mnt);
720
721         if (oflag & O_CREAT) {
722                 if (dentry->d_inode) {  /* entry already exists */
723                         audit_inode(name, dentry);
724                         error = -EEXIST;
725                         if (oflag & O_EXCL)
726                                 goto out;
727                         filp = do_open(ipc_ns, dentry, oflag);
728                 } else {
729                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
730                                                 dentry, oflag, mode,
731                                                 u_attr ? &attr : NULL);
732                 }
733         } else {
734                 error = -ENOENT;
735                 if (!dentry->d_inode)
736                         goto out;
737                 audit_inode(name, dentry);
738                 filp = do_open(ipc_ns, dentry, oflag);
739         }
740
741         if (IS_ERR(filp)) {
742                 error = PTR_ERR(filp);
743                 goto out_putfd;
744         }
745
746         fd_install(fd, filp);
747         goto out_upsem;
748
749 out:
750         dput(dentry);
751         mntput(ipc_ns->mq_mnt);
752 out_putfd:
753         put_unused_fd(fd);
754 out_err:
755         fd = error;
756 out_upsem:
757         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
758 out_putname:
759         putname(name);
760         return fd;
761 }
762
763 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
764 {
765         int err;
766         char *name;
767         struct dentry *dentry;
768         struct inode *inode = NULL;
769         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
770
771         name = getname(u_name);
772         if (IS_ERR(name))
773                 return PTR_ERR(name);
774
775         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
776                         I_MUTEX_PARENT);
777         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
778         if (IS_ERR(dentry)) {
779                 err = PTR_ERR(dentry);
780                 goto out_unlock;
781         }
782
783         if (!dentry->d_inode) {
784                 err = -ENOENT;
785                 goto out_err;
786         }
787
788         inode = dentry->d_inode;
789         if (inode)
790                 atomic_inc(&inode->i_count);
791         err = mnt_want_write(ipc_ns->mq_mnt);
792         if (err)
793                 goto out_err;
794         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
795         mnt_drop_write(ipc_ns->mq_mnt);
796 out_err:
797         dput(dentry);
798
799 out_unlock:
800         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
801         putname(name);
802         if (inode)
803                 iput(inode);
804
805         return err;
806 }
807
808 /* Pipelined send and receive functions.
809  *
810  * If a receiver finds no waiting message, then it registers itself in the
811  * list of waiting receivers. A sender checks that list before adding the new
812  * message into the message array. If there is a waiting receiver, then it
813  * bypasses the message array and directly hands the message over to the
814  * receiver.
815  * The receiver accepts the message and returns without grabbing the queue
816  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
817  * are necessary. The same algorithm is used for sysv semaphores, see
818  * ipc/sem.c for more details.
819  *
820  * The same algorithm is used for senders.
821  */
822
823 /* pipelined_send() - send a message directly to the task waiting in
824  * sys_mq_timedreceive() (without inserting message into a queue).
825  */
826 static inline void pipelined_send(struct mqueue_inode_info *info,
827                                   struct msg_msg *message,
828                                   struct ext_wait_queue *receiver)
829 {
830         receiver->msg = message;
831         list_del(&receiver->list);
832         receiver->state = STATE_PENDING;
833         wake_up_process(receiver->task);
834         smp_wmb();
835         receiver->state = STATE_READY;
836 }
837
838 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
839  * gets its message and put to the queue (we have one free place for sure). */
840 static inline void pipelined_receive(struct mqueue_inode_info *info)
841 {
842         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
843
844         if (!sender) {
845                 /* for poll */
846                 wake_up_interruptible(&info->wait_q);
847                 return;
848         }
849         msg_insert(sender->msg, info);
850         list_del(&sender->list);
851         sender->state = STATE_PENDING;
852         wake_up_process(sender->task);
853         smp_wmb();
854         sender->state = STATE_READY;
855 }
856
857 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
858                 size_t, msg_len, unsigned int, msg_prio,
859                 const struct timespec __user *, u_abs_timeout)
860 {
861         struct file *filp;
862         struct inode *inode;
863         struct ext_wait_queue wait;
864         struct ext_wait_queue *receiver;
865         struct msg_msg *msg_ptr;
866         struct mqueue_inode_info *info;
867         struct timespec ts, *p = NULL;
868         long timeout;
869         int ret;
870
871         if (u_abs_timeout) {
872                 if (copy_from_user(&ts, u_abs_timeout, 
873                                         sizeof(struct timespec)))
874                         return -EFAULT;
875                 p = &ts;
876         }
877
878         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
879                 return -EINVAL;
880
881         audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
882         timeout = prepare_timeout(p);
883
884         ret = -EBADF;
885         filp = fget(mqdes);
886         if (unlikely(!filp))
887                 goto out;
888
889         inode = filp->f_path.dentry->d_inode;
890         if (unlikely(filp->f_op != &mqueue_file_operations))
891                 goto out_fput;
892         info = MQUEUE_I(inode);
893         audit_inode(NULL, filp->f_path.dentry);
894
895         if (unlikely(!(filp->f_mode & FMODE_WRITE)))
896                 goto out_fput;
897
898         if (unlikely(msg_len > info->attr.mq_msgsize)) {
899                 ret = -EMSGSIZE;
900                 goto out_fput;
901         }
902
903         /* First try to allocate memory, before doing anything with
904          * existing queues. */
905         msg_ptr = load_msg(u_msg_ptr, msg_len);
906         if (IS_ERR(msg_ptr)) {
907                 ret = PTR_ERR(msg_ptr);
908                 goto out_fput;
909         }
910         msg_ptr->m_ts = msg_len;
911         msg_ptr->m_type = msg_prio;
912
913         spin_lock(&info->lock);
914
915         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
916                 if (filp->f_flags & O_NONBLOCK) {
917                         spin_unlock(&info->lock);
918                         ret = -EAGAIN;
919                 } else if (unlikely(timeout < 0)) {
920                         spin_unlock(&info->lock);
921                         ret = timeout;
922                 } else {
923                         wait.task = current;
924                         wait.msg = (void *) msg_ptr;
925                         wait.state = STATE_NONE;
926                         ret = wq_sleep(info, SEND, timeout, &wait);
927                 }
928                 if (ret < 0)
929                         free_msg(msg_ptr);
930         } else {
931                 receiver = wq_get_first_waiter(info, RECV);
932                 if (receiver) {
933                         pipelined_send(info, msg_ptr, receiver);
934                 } else {
935                         /* adds message to the queue */
936                         msg_insert(msg_ptr, info);
937                         __do_notify(info);
938                 }
939                 inode->i_atime = inode->i_mtime = inode->i_ctime =
940                                 CURRENT_TIME;
941                 spin_unlock(&info->lock);
942                 ret = 0;
943         }
944 out_fput:
945         fput(filp);
946 out:
947         return ret;
948 }
949
950 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
951                 size_t, msg_len, unsigned int __user *, u_msg_prio,
952                 const struct timespec __user *, u_abs_timeout)
953 {
954         long timeout;
955         ssize_t ret;
956         struct msg_msg *msg_ptr;
957         struct file *filp;
958         struct inode *inode;
959         struct mqueue_inode_info *info;
960         struct ext_wait_queue wait;
961         struct timespec ts, *p = NULL;
962
963         if (u_abs_timeout) {
964                 if (copy_from_user(&ts, u_abs_timeout, 
965                                         sizeof(struct timespec)))
966                         return -EFAULT;
967                 p = &ts;
968         }
969
970         audit_mq_sendrecv(mqdes, msg_len, 0, p);
971         timeout = prepare_timeout(p);
972
973         ret = -EBADF;
974         filp = fget(mqdes);
975         if (unlikely(!filp))
976                 goto out;
977
978         inode = filp->f_path.dentry->d_inode;
979         if (unlikely(filp->f_op != &mqueue_file_operations))
980                 goto out_fput;
981         info = MQUEUE_I(inode);
982         audit_inode(NULL, filp->f_path.dentry);
983
984         if (unlikely(!(filp->f_mode & FMODE_READ)))
985                 goto out_fput;
986
987         /* checks if buffer is big enough */
988         if (unlikely(msg_len < info->attr.mq_msgsize)) {
989                 ret = -EMSGSIZE;
990                 goto out_fput;
991         }
992
993         spin_lock(&info->lock);
994         if (info->attr.mq_curmsgs == 0) {
995                 if (filp->f_flags & O_NONBLOCK) {
996                         spin_unlock(&info->lock);
997                         ret = -EAGAIN;
998                         msg_ptr = NULL;
999                 } else if (unlikely(timeout < 0)) {
1000                         spin_unlock(&info->lock);
1001                         ret = timeout;
1002                         msg_ptr = NULL;
1003                 } else {
1004                         wait.task = current;
1005                         wait.state = STATE_NONE;
1006                         ret = wq_sleep(info, RECV, timeout, &wait);
1007                         msg_ptr = wait.msg;
1008                 }
1009         } else {
1010                 msg_ptr = msg_get(info);
1011
1012                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1013                                 CURRENT_TIME;
1014
1015                 /* There is now free space in queue. */
1016                 pipelined_receive(info);
1017                 spin_unlock(&info->lock);
1018                 ret = 0;
1019         }
1020         if (ret == 0) {
1021                 ret = msg_ptr->m_ts;
1022
1023                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1024                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1025                         ret = -EFAULT;
1026                 }
1027                 free_msg(msg_ptr);
1028         }
1029 out_fput:
1030         fput(filp);
1031 out:
1032         return ret;
1033 }
1034
1035 /*
1036  * Notes: the case when user wants us to deregister (with NULL as pointer)
1037  * and he isn't currently owner of notification, will be silently discarded.
1038  * It isn't explicitly defined in the POSIX.
1039  */
1040 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1041                 const struct sigevent __user *, u_notification)
1042 {
1043         int ret;
1044         struct file *filp;
1045         struct sock *sock;
1046         struct inode *inode;
1047         struct sigevent notification;
1048         struct mqueue_inode_info *info;
1049         struct sk_buff *nc;
1050
1051         if (u_notification) {
1052                 if (copy_from_user(&notification, u_notification,
1053                                         sizeof(struct sigevent)))
1054                         return -EFAULT;
1055         }
1056
1057         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1058
1059         nc = NULL;
1060         sock = NULL;
1061         if (u_notification != NULL) {
1062                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1063                              notification.sigev_notify != SIGEV_SIGNAL &&
1064                              notification.sigev_notify != SIGEV_THREAD))
1065                         return -EINVAL;
1066                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1067                         !valid_signal(notification.sigev_signo)) {
1068                         return -EINVAL;
1069                 }
1070                 if (notification.sigev_notify == SIGEV_THREAD) {
1071                         long timeo;
1072
1073                         /* create the notify skb */
1074                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1075                         ret = -ENOMEM;
1076                         if (!nc)
1077                                 goto out;
1078                         ret = -EFAULT;
1079                         if (copy_from_user(nc->data,
1080                                         notification.sigev_value.sival_ptr,
1081                                         NOTIFY_COOKIE_LEN)) {
1082                                 goto out;
1083                         }
1084
1085                         /* TODO: add a header? */
1086                         skb_put(nc, NOTIFY_COOKIE_LEN);
1087                         /* and attach it to the socket */
1088 retry:
1089                         filp = fget(notification.sigev_signo);
1090                         ret = -EBADF;
1091                         if (!filp)
1092                                 goto out;
1093                         sock = netlink_getsockbyfilp(filp);
1094                         fput(filp);
1095                         if (IS_ERR(sock)) {
1096                                 ret = PTR_ERR(sock);
1097                                 sock = NULL;
1098                                 goto out;
1099                         }
1100
1101                         timeo = MAX_SCHEDULE_TIMEOUT;
1102                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1103                         if (ret == 1)
1104                                 goto retry;
1105                         if (ret) {
1106                                 sock = NULL;
1107                                 nc = NULL;
1108                                 goto out;
1109                         }
1110                 }
1111         }
1112
1113         ret = -EBADF;
1114         filp = fget(mqdes);
1115         if (!filp)
1116                 goto out;
1117
1118         inode = filp->f_path.dentry->d_inode;
1119         if (unlikely(filp->f_op != &mqueue_file_operations))
1120                 goto out_fput;
1121         info = MQUEUE_I(inode);
1122
1123         ret = 0;
1124         spin_lock(&info->lock);
1125         if (u_notification == NULL) {
1126                 if (info->notify_owner == task_tgid(current)) {
1127                         remove_notification(info);
1128                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1129                 }
1130         } else if (info->notify_owner != NULL) {
1131                 ret = -EBUSY;
1132         } else {
1133                 switch (notification.sigev_notify) {
1134                 case SIGEV_NONE:
1135                         info->notify.sigev_notify = SIGEV_NONE;
1136                         break;
1137                 case SIGEV_THREAD:
1138                         info->notify_sock = sock;
1139                         info->notify_cookie = nc;
1140                         sock = NULL;
1141                         nc = NULL;
1142                         info->notify.sigev_notify = SIGEV_THREAD;
1143                         break;
1144                 case SIGEV_SIGNAL:
1145                         info->notify.sigev_signo = notification.sigev_signo;
1146                         info->notify.sigev_value = notification.sigev_value;
1147                         info->notify.sigev_notify = SIGEV_SIGNAL;
1148                         break;
1149                 }
1150
1151                 info->notify_owner = get_pid(task_tgid(current));
1152                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1153         }
1154         spin_unlock(&info->lock);
1155 out_fput:
1156         fput(filp);
1157 out:
1158         if (sock) {
1159                 netlink_detachskb(sock, nc);
1160         } else if (nc) {
1161                 dev_kfree_skb(nc);
1162         }
1163         return ret;
1164 }
1165
1166 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1167                 const struct mq_attr __user *, u_mqstat,
1168                 struct mq_attr __user *, u_omqstat)
1169 {
1170         int ret;
1171         struct mq_attr mqstat, omqstat;
1172         struct file *filp;
1173         struct inode *inode;
1174         struct mqueue_inode_info *info;
1175
1176         if (u_mqstat != NULL) {
1177                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1178                         return -EFAULT;
1179                 if (mqstat.mq_flags & (~O_NONBLOCK))
1180                         return -EINVAL;
1181         }
1182
1183         ret = -EBADF;
1184         filp = fget(mqdes);
1185         if (!filp)
1186                 goto out;
1187
1188         inode = filp->f_path.dentry->d_inode;
1189         if (unlikely(filp->f_op != &mqueue_file_operations))
1190                 goto out_fput;
1191         info = MQUEUE_I(inode);
1192
1193         spin_lock(&info->lock);
1194
1195         omqstat = info->attr;
1196         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1197         if (u_mqstat) {
1198                 audit_mq_getsetattr(mqdes, &mqstat);
1199                 spin_lock(&filp->f_lock);
1200                 if (mqstat.mq_flags & O_NONBLOCK)
1201                         filp->f_flags |= O_NONBLOCK;
1202                 else
1203                         filp->f_flags &= ~O_NONBLOCK;
1204                 spin_unlock(&filp->f_lock);
1205
1206                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1207         }
1208
1209         spin_unlock(&info->lock);
1210
1211         ret = 0;
1212         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1213                                                 sizeof(struct mq_attr)))
1214                 ret = -EFAULT;
1215
1216 out_fput:
1217         fput(filp);
1218 out:
1219         return ret;
1220 }
1221
1222 static const struct inode_operations mqueue_dir_inode_operations = {
1223         .lookup = simple_lookup,
1224         .create = mqueue_create,
1225         .unlink = mqueue_unlink,
1226 };
1227
1228 static const struct file_operations mqueue_file_operations = {
1229         .flush = mqueue_flush_file,
1230         .poll = mqueue_poll_file,
1231         .read = mqueue_read_file,
1232 };
1233
1234 static struct super_operations mqueue_super_ops = {
1235         .alloc_inode = mqueue_alloc_inode,
1236         .destroy_inode = mqueue_destroy_inode,
1237         .statfs = simple_statfs,
1238         .delete_inode = mqueue_delete_inode,
1239         .drop_inode = generic_delete_inode,
1240 };
1241
1242 static struct file_system_type mqueue_fs_type = {
1243         .name = "mqueue",
1244         .get_sb = mqueue_get_sb,
1245         .kill_sb = kill_litter_super,
1246 };
1247
1248 int mq_init_ns(struct ipc_namespace *ns)
1249 {
1250         ns->mq_queues_count  = 0;
1251         ns->mq_queues_max    = DFLT_QUEUESMAX;
1252         ns->mq_msg_max       = DFLT_MSGMAX;
1253         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1254
1255         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1256         if (IS_ERR(ns->mq_mnt)) {
1257                 int err = PTR_ERR(ns->mq_mnt);
1258                 ns->mq_mnt = NULL;
1259                 return err;
1260         }
1261         return 0;
1262 }
1263
1264 void mq_clear_sbinfo(struct ipc_namespace *ns)
1265 {
1266         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1267 }
1268
1269 void mq_put_mnt(struct ipc_namespace *ns)
1270 {
1271         mntput(ns->mq_mnt);
1272 }
1273
1274 static int msg_max_limit_min = MIN_MSGMAX;
1275 static int msg_max_limit_max = MAX_MSGMAX;
1276
1277 static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
1278 static int msg_maxsize_limit_max = MAX_MSGSIZEMAX;
1279
1280 static ctl_table mq_sysctls[] = {
1281         {
1282                 .procname       = "queues_max",
1283                 .data           = &init_ipc_ns.mq_queues_max,
1284                 .maxlen         = sizeof(int),
1285                 .mode           = 0644,
1286                 .proc_handler   = &proc_dointvec,
1287         },
1288         {
1289                 .procname       = "msg_max",
1290                 .data           = &init_ipc_ns.mq_msg_max,
1291                 .maxlen         = sizeof(int),
1292                 .mode           = 0644,
1293                 .proc_handler   = &proc_dointvec_minmax,
1294                 .extra1         = &msg_max_limit_min,
1295                 .extra2         = &msg_max_limit_max,
1296         },
1297         {
1298                 .procname       = "msgsize_max",
1299                 .data           = &init_ipc_ns.mq_msgsize_max,
1300                 .maxlen         = sizeof(int),
1301                 .mode           = 0644,
1302                 .proc_handler   = &proc_dointvec_minmax,
1303                 .extra1         = &msg_maxsize_limit_min,
1304                 .extra2         = &msg_maxsize_limit_max,
1305         },
1306         { .ctl_name = 0 }
1307 };
1308
1309 static ctl_table mq_sysctl_dir[] = {
1310         {
1311                 .procname       = "mqueue",
1312                 .mode           = 0555,
1313                 .child          = mq_sysctls,
1314         },
1315         { .ctl_name = 0 }
1316 };
1317
1318 static ctl_table mq_sysctl_root[] = {
1319         {
1320                 .ctl_name       = CTL_FS,
1321                 .procname       = "fs",
1322                 .mode           = 0555,
1323                 .child          = mq_sysctl_dir,
1324         },
1325         { .ctl_name = 0 }
1326 };
1327
1328 static int __init init_mqueue_fs(void)
1329 {
1330         int error;
1331
1332         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1333                                 sizeof(struct mqueue_inode_info), 0,
1334                                 SLAB_HWCACHE_ALIGN, init_once);
1335         if (mqueue_inode_cachep == NULL)
1336                 return -ENOMEM;
1337
1338         /* ignore failues - they are not fatal */
1339         mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
1340
1341         error = register_filesystem(&mqueue_fs_type);
1342         if (error)
1343                 goto out_sysctl;
1344
1345         spin_lock_init(&mq_lock);
1346
1347         init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1348         if (IS_ERR(init_ipc_ns.mq_mnt)) {
1349                 error = PTR_ERR(init_ipc_ns.mq_mnt);
1350                 goto out_filesystem;
1351         }
1352
1353         return 0;
1354
1355 out_filesystem:
1356         unregister_filesystem(&mqueue_fs_type);
1357 out_sysctl:
1358         if (mq_sysctl_table)
1359                 unregister_sysctl_table(mq_sysctl_table);
1360         kmem_cache_destroy(mqueue_inode_cachep);
1361         return error;
1362 }
1363
1364 __initcall(init_mqueue_fs);