blob: 41ecbd440feda782dd3ac9949632458c16fd4de8 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * POSIX message queues filesystem for Linux.
3 *
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
Michal Wronski65163fd2005-11-06 21:31:54 +01005 * Michal Wronski (Michal.Wronski@motorola.com)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
10 *
11 * This file is released under the GPL.
12 */
13
Randy.Dunlapc59ede72006-01-11 12:17:46 -080014#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
16#include <linux/pagemap.h>
17#include <linux/file.h>
18#include <linux/mount.h>
19#include <linux/namei.h>
20#include <linux/sysctl.h>
21#include <linux/poll.h>
22#include <linux/mqueue.h>
23#include <linux/msg.h>
24#include <linux/skbuff.h>
25#include <linux/netlink.h>
26#include <linux/syscalls.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070027#include <linux/signal.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080028#include <linux/mutex.h>
29
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <net/sock.h>
31#include "util.h"
32
33#define MQUEUE_MAGIC 0x19800202
34#define DIRENT_SIZE 20
35#define FILENT_SIZE 80
36
37#define SEND 0
38#define RECV 1
39
40#define STATE_NONE 0
41#define STATE_PENDING 1
42#define STATE_READY 2
43
44/* used by sysctl */
45#define FS_MQUEUE 1
46#define CTL_QUEUESMAX 2
47#define CTL_MSGMAX 3
48#define CTL_MSGSIZEMAX 4
49
50/* default values */
51#define DFLT_QUEUESMAX 256 /* max number of message queues */
52#define DFLT_MSGMAX 10 /* max number of messages in each queue */
53#define HARD_MSGMAX (131072/sizeof(void*))
54#define DFLT_MSGSIZEMAX 8192 /* max message size */
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57struct ext_wait_queue { /* queue of sleeping tasks */
58 struct task_struct *task;
59 struct list_head list;
60 struct msg_msg *msg; /* ptr of loaded message */
61 int state; /* one of STATE_* values */
62};
63
64struct mqueue_inode_info {
65 spinlock_t lock;
66 struct inode vfs_inode;
67 wait_queue_head_t wait_q;
68
69 struct msg_msg **messages;
70 struct mq_attr attr;
71
72 struct sigevent notify;
73 pid_t notify_owner;
Adrian Bunk338cec32005-09-10 00:26:54 -070074 struct user_struct *user; /* user who created, for accounting */
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 struct sock *notify_sock;
76 struct sk_buff *notify_cookie;
77
78 /* for tasks waiting for free space and messages, respectively */
79 struct ext_wait_queue e_wait_q[2];
80
81 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
82};
83
84static struct inode_operations mqueue_dir_inode_operations;
85static struct file_operations mqueue_file_operations;
86static struct super_operations mqueue_super_ops;
87static void remove_notification(struct mqueue_inode_info *info);
88
89static spinlock_t mq_lock;
90static kmem_cache_t *mqueue_inode_cachep;
91static struct vfsmount *mqueue_mnt;
92
93static unsigned int queues_count;
94static unsigned int queues_max = DFLT_QUEUESMAX;
95static unsigned int msg_max = DFLT_MSGMAX;
96static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
97
98static struct ctl_table_header * mq_sysctl_table;
99
100static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
101{
102 return container_of(inode, struct mqueue_inode_info, vfs_inode);
103}
104
105static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
106 struct mq_attr *attr)
107{
108 struct inode *inode;
109
110 inode = new_inode(sb);
111 if (inode) {
112 inode->i_mode = mode;
113 inode->i_uid = current->fsuid;
114 inode->i_gid = current->fsgid;
115 inode->i_blksize = PAGE_CACHE_SIZE;
116 inode->i_blocks = 0;
117 inode->i_mtime = inode->i_ctime = inode->i_atime =
118 CURRENT_TIME;
119
120 if (S_ISREG(mode)) {
121 struct mqueue_inode_info *info;
122 struct task_struct *p = current;
123 struct user_struct *u = p->user;
124 unsigned long mq_bytes, mq_msg_tblsz;
125
126 inode->i_fop = &mqueue_file_operations;
127 inode->i_size = FILENT_SIZE;
128 /* mqueue specific info */
129 info = MQUEUE_I(inode);
130 spin_lock_init(&info->lock);
131 init_waitqueue_head(&info->wait_q);
132 INIT_LIST_HEAD(&info->e_wait_q[0].list);
133 INIT_LIST_HEAD(&info->e_wait_q[1].list);
134 info->messages = NULL;
135 info->notify_owner = 0;
136 info->qsize = 0;
137 info->user = NULL; /* set when all is ok */
138 memset(&info->attr, 0, sizeof(info->attr));
139 info->attr.mq_maxmsg = DFLT_MSGMAX;
140 info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
141 if (attr) {
142 info->attr.mq_maxmsg = attr->mq_maxmsg;
143 info->attr.mq_msgsize = attr->mq_msgsize;
144 }
145 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
146 mq_bytes = (mq_msg_tblsz +
147 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
148
149 spin_lock(&mq_lock);
150 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
151 u->mq_bytes + mq_bytes >
152 p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
153 spin_unlock(&mq_lock);
154 goto out_inode;
155 }
156 u->mq_bytes += mq_bytes;
157 spin_unlock(&mq_lock);
158
159 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
160 if (!info->messages) {
161 spin_lock(&mq_lock);
162 u->mq_bytes -= mq_bytes;
163 spin_unlock(&mq_lock);
164 goto out_inode;
165 }
166 /* all is ok */
167 info->user = get_uid(u);
168 } else if (S_ISDIR(mode)) {
169 inode->i_nlink++;
170 /* Some things misbehave if size == 0 on a directory */
171 inode->i_size = 2 * DIRENT_SIZE;
172 inode->i_op = &mqueue_dir_inode_operations;
173 inode->i_fop = &simple_dir_operations;
174 }
175 }
176 return inode;
177out_inode:
178 make_bad_inode(inode);
179 iput(inode);
180 return NULL;
181}
182
183static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
184{
185 struct inode *inode;
186
187 sb->s_blocksize = PAGE_CACHE_SIZE;
188 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
189 sb->s_magic = MQUEUE_MAGIC;
190 sb->s_op = &mqueue_super_ops;
191
192 inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
193 if (!inode)
194 return -ENOMEM;
195
196 sb->s_root = d_alloc_root(inode);
197 if (!sb->s_root) {
198 iput(inode);
199 return -ENOMEM;
200 }
201
202 return 0;
203}
204
205static struct super_block *mqueue_get_sb(struct file_system_type *fs_type,
206 int flags, const char *dev_name,
207 void *data)
208{
209 return get_sb_single(fs_type, flags, data, mqueue_fill_super);
210}
211
212static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags)
213{
214 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
215
216 if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
217 SLAB_CTOR_CONSTRUCTOR)
218 inode_init_once(&p->vfs_inode);
219}
220
221static struct inode *mqueue_alloc_inode(struct super_block *sb)
222{
223 struct mqueue_inode_info *ei;
224
225 ei = kmem_cache_alloc(mqueue_inode_cachep, SLAB_KERNEL);
226 if (!ei)
227 return NULL;
228 return &ei->vfs_inode;
229}
230
231static void mqueue_destroy_inode(struct inode *inode)
232{
233 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
234}
235
236static void mqueue_delete_inode(struct inode *inode)
237{
238 struct mqueue_inode_info *info;
239 struct user_struct *user;
240 unsigned long mq_bytes;
241 int i;
242
243 if (S_ISDIR(inode->i_mode)) {
244 clear_inode(inode);
245 return;
246 }
247 info = MQUEUE_I(inode);
248 spin_lock(&info->lock);
249 for (i = 0; i < info->attr.mq_curmsgs; i++)
250 free_msg(info->messages[i]);
251 kfree(info->messages);
252 spin_unlock(&info->lock);
253
254 clear_inode(inode);
255
256 mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
257 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
258 user = info->user;
259 if (user) {
260 spin_lock(&mq_lock);
261 user->mq_bytes -= mq_bytes;
262 queues_count--;
263 spin_unlock(&mq_lock);
264 free_uid(user);
265 }
266}
267
268static int mqueue_create(struct inode *dir, struct dentry *dentry,
269 int mode, struct nameidata *nd)
270{
271 struct inode *inode;
272 struct mq_attr *attr = dentry->d_fsdata;
273 int error;
274
275 spin_lock(&mq_lock);
276 if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
277 error = -ENOSPC;
278 goto out_lock;
279 }
280 queues_count++;
281 spin_unlock(&mq_lock);
282
283 inode = mqueue_get_inode(dir->i_sb, mode, attr);
284 if (!inode) {
285 error = -ENOMEM;
286 spin_lock(&mq_lock);
287 queues_count--;
288 goto out_lock;
289 }
290
291 dir->i_size += DIRENT_SIZE;
292 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
293
294 d_instantiate(dentry, inode);
295 dget(dentry);
296 return 0;
297out_lock:
298 spin_unlock(&mq_lock);
299 return error;
300}
301
302static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
303{
304 struct inode *inode = dentry->d_inode;
305
306 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
307 dir->i_size -= DIRENT_SIZE;
308 inode->i_nlink--;
309 dput(dentry);
310 return 0;
311}
312
313/*
314* This is routine for system read from queue file.
315* To avoid mess with doing here some sort of mq_receive we allow
316* to read only queue size & notification info (the only values
317* that are interesting from user point of view and aren't accessible
318* through std routines)
319*/
320static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
321 size_t count, loff_t * off)
322{
323 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
324 char buffer[FILENT_SIZE];
325 size_t slen;
326 loff_t o;
327
328 if (!count)
329 return 0;
330
331 spin_lock(&info->lock);
332 snprintf(buffer, sizeof(buffer),
333 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
334 info->qsize,
335 info->notify_owner ? info->notify.sigev_notify : 0,
336 (info->notify_owner &&
337 info->notify.sigev_notify == SIGEV_SIGNAL) ?
338 info->notify.sigev_signo : 0,
339 info->notify_owner);
340 spin_unlock(&info->lock);
341 buffer[sizeof(buffer)-1] = '\0';
342 slen = strlen(buffer)+1;
343
344 o = *off;
345 if (o > slen)
346 return 0;
347
348 if (o + count > slen)
349 count = slen - o;
350
351 if (copy_to_user(u_data, buffer + o, count))
352 return -EFAULT;
353
354 *off = o + count;
355 filp->f_dentry->d_inode->i_atime = filp->f_dentry->d_inode->i_ctime = CURRENT_TIME;
356 return count;
357}
358
359static int mqueue_flush_file(struct file *filp)
360{
361 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
362
363 spin_lock(&info->lock);
364 if (current->tgid == info->notify_owner)
365 remove_notification(info);
366
367 spin_unlock(&info->lock);
368 return 0;
369}
370
371static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
372{
373 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
374 int retval = 0;
375
376 poll_wait(filp, &info->wait_q, poll_tab);
377
378 spin_lock(&info->lock);
379 if (info->attr.mq_curmsgs)
380 retval = POLLIN | POLLRDNORM;
381
382 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
383 retval |= POLLOUT | POLLWRNORM;
384 spin_unlock(&info->lock);
385
386 return retval;
387}
388
389/* Adds current to info->e_wait_q[sr] before element with smaller prio */
390static void wq_add(struct mqueue_inode_info *info, int sr,
391 struct ext_wait_queue *ewp)
392{
393 struct ext_wait_queue *walk;
394
395 ewp->task = current;
396
397 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
398 if (walk->task->static_prio <= current->static_prio) {
399 list_add_tail(&ewp->list, &walk->list);
400 return;
401 }
402 }
403 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
404}
405
406/*
407 * Puts current task to sleep. Caller must hold queue lock. After return
408 * lock isn't held.
409 * sr: SEND or RECV
410 */
411static int wq_sleep(struct mqueue_inode_info *info, int sr,
412 long timeout, struct ext_wait_queue *ewp)
413{
414 int retval;
415 signed long time;
416
417 wq_add(info, sr, ewp);
418
419 for (;;) {
420 set_current_state(TASK_INTERRUPTIBLE);
421
422 spin_unlock(&info->lock);
423 time = schedule_timeout(timeout);
424
425 while (ewp->state == STATE_PENDING)
426 cpu_relax();
427
428 if (ewp->state == STATE_READY) {
429 retval = 0;
430 goto out;
431 }
432 spin_lock(&info->lock);
433 if (ewp->state == STATE_READY) {
434 retval = 0;
435 goto out_unlock;
436 }
437 if (signal_pending(current)) {
438 retval = -ERESTARTSYS;
439 break;
440 }
441 if (time == 0) {
442 retval = -ETIMEDOUT;
443 break;
444 }
445 }
446 list_del(&ewp->list);
447out_unlock:
448 spin_unlock(&info->lock);
449out:
450 return retval;
451}
452
453/*
454 * Returns waiting task that should be serviced first or NULL if none exists
455 */
456static struct ext_wait_queue *wq_get_first_waiter(
457 struct mqueue_inode_info *info, int sr)
458{
459 struct list_head *ptr;
460
461 ptr = info->e_wait_q[sr].list.prev;
462 if (ptr == &info->e_wait_q[sr].list)
463 return NULL;
464 return list_entry(ptr, struct ext_wait_queue, list);
465}
466
467/* Auxiliary functions to manipulate messages' list */
468static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
469{
470 int k;
471
472 k = info->attr.mq_curmsgs - 1;
473 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
474 info->messages[k + 1] = info->messages[k];
475 k--;
476 }
477 info->attr.mq_curmsgs++;
478 info->qsize += ptr->m_ts;
479 info->messages[k + 1] = ptr;
480}
481
482static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
483{
484 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
485 return info->messages[info->attr.mq_curmsgs];
486}
487
488static inline void set_cookie(struct sk_buff *skb, char code)
489{
490 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
491}
492
493/*
494 * The next function is only to split too long sys_mq_timedsend
495 */
496static void __do_notify(struct mqueue_inode_info *info)
497{
498 /* notification
499 * invoked when there is registered process and there isn't process
500 * waiting synchronously for message AND state of queue changed from
501 * empty to not empty. Here we are sure that no one is waiting
502 * synchronously. */
503 if (info->notify_owner &&
504 info->attr.mq_curmsgs == 1) {
505 struct siginfo sig_i;
506 switch (info->notify.sigev_notify) {
507 case SIGEV_NONE:
508 break;
509 case SIGEV_SIGNAL:
510 /* sends signal */
511
512 sig_i.si_signo = info->notify.sigev_signo;
513 sig_i.si_errno = 0;
514 sig_i.si_code = SI_MESGQ;
515 sig_i.si_value = info->notify.sigev_value;
516 sig_i.si_pid = current->tgid;
517 sig_i.si_uid = current->uid;
518
519 kill_proc_info(info->notify.sigev_signo,
520 &sig_i, info->notify_owner);
521 break;
522 case SIGEV_THREAD:
523 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
524 netlink_sendskb(info->notify_sock,
525 info->notify_cookie, 0);
526 break;
527 }
528 /* after notification unregisters process */
529 info->notify_owner = 0;
530 }
531 wake_up(&info->wait_q);
532}
533
534static long prepare_timeout(const struct timespec __user *u_arg)
535{
536 struct timespec ts, nowts;
537 long timeout;
538
539 if (u_arg) {
540 if (unlikely(copy_from_user(&ts, u_arg,
541 sizeof(struct timespec))))
542 return -EFAULT;
543
544 if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
545 || ts.tv_nsec >= NSEC_PER_SEC))
546 return -EINVAL;
547 nowts = CURRENT_TIME;
548 /* first subtract as jiffies can't be too big */
549 ts.tv_sec -= nowts.tv_sec;
550 if (ts.tv_nsec < nowts.tv_nsec) {
551 ts.tv_nsec += NSEC_PER_SEC;
552 ts.tv_sec--;
553 }
554 ts.tv_nsec -= nowts.tv_nsec;
555 if (ts.tv_sec < 0)
556 return 0;
557
558 timeout = timespec_to_jiffies(&ts) + 1;
559 } else
560 return MAX_SCHEDULE_TIMEOUT;
561
562 return timeout;
563}
564
565static void remove_notification(struct mqueue_inode_info *info)
566{
567 if (info->notify_owner != 0 &&
568 info->notify.sigev_notify == SIGEV_THREAD) {
569 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
570 netlink_sendskb(info->notify_sock, info->notify_cookie, 0);
571 }
572 info->notify_owner = 0;
573}
574
575static int mq_attr_ok(struct mq_attr *attr)
576{
577 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
578 return 0;
579 if (capable(CAP_SYS_RESOURCE)) {
580 if (attr->mq_maxmsg > HARD_MSGMAX)
581 return 0;
582 } else {
583 if (attr->mq_maxmsg > msg_max ||
584 attr->mq_msgsize > msgsize_max)
585 return 0;
586 }
587 /* check for overflow */
588 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
589 return 0;
590 if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
591 (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
592 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
593 return 0;
594 return 1;
595}
596
597/*
598 * Invoked when creating a new queue via sys_mq_open
599 */
600static struct file *do_create(struct dentry *dir, struct dentry *dentry,
601 int oflag, mode_t mode, struct mq_attr __user *u_attr)
602{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 struct mq_attr attr;
604 int ret;
605
Alexander Viro7c7dce92006-01-14 15:29:55 -0500606 if (u_attr) {
607 ret = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 if (copy_from_user(&attr, u_attr, sizeof(attr)))
Alexander Viro7c7dce92006-01-14 15:29:55 -0500609 goto out;
610 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 if (!mq_attr_ok(&attr))
Alexander Viro7c7dce92006-01-14 15:29:55 -0500612 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 /* store for use during create */
614 dentry->d_fsdata = &attr;
615 }
616
Krzysztof Benedyczak59175832005-09-27 22:21:36 +0200617 mode &= ~current->fs->umask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
619 dentry->d_fsdata = NULL;
620 if (ret)
Alexander Viro7c7dce92006-01-14 15:29:55 -0500621 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622
Alexander Viro7c7dce92006-01-14 15:29:55 -0500623 return dentry_open(dentry, mqueue_mnt, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Alexander Viro7c7dce92006-01-14 15:29:55 -0500625out:
626 dput(dentry);
627 mntput(mqueue_mnt);
628 return ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629}
630
631/* Opens existing queue */
632static struct file *do_open(struct dentry *dentry, int oflag)
633{
634static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
635 MAY_READ | MAY_WRITE };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
Alexander Viro7c7dce92006-01-14 15:29:55 -0500637 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
638 dput(dentry);
639 mntput(mqueue_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 return ERR_PTR(-EINVAL);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500641 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642
Alexander Viro7c7dce92006-01-14 15:29:55 -0500643 if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
644 dput(dentry);
645 mntput(mqueue_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 return ERR_PTR(-EACCES);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500647 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648
Alexander Viro7c7dce92006-01-14 15:29:55 -0500649 return dentry_open(dentry, mqueue_mnt, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650}
651
652asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
653 struct mq_attr __user *u_attr)
654{
655 struct dentry *dentry;
656 struct file *filp;
657 char *name;
658 int fd, error;
659
660 if (IS_ERR(name = getname(u_name)))
661 return PTR_ERR(name);
662
663 fd = get_unused_fd();
664 if (fd < 0)
665 goto out_putname;
666
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800667 mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
669 if (IS_ERR(dentry)) {
670 error = PTR_ERR(dentry);
671 goto out_err;
672 }
673 mntget(mqueue_mnt);
674
675 if (oflag & O_CREAT) {
676 if (dentry->d_inode) { /* entry already exists */
Alexander Viro7c7dce92006-01-14 15:29:55 -0500677 error = -EEXIST;
678 if (oflag & O_EXCL)
679 goto out;
680 filp = do_open(dentry, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 } else {
682 filp = do_create(mqueue_mnt->mnt_root, dentry,
683 oflag, mode, u_attr);
684 }
Alexander Viro7c7dce92006-01-14 15:29:55 -0500685 } else {
686 error = -ENOENT;
687 if (!dentry->d_inode)
688 goto out;
689 filp = do_open(dentry, oflag);
690 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691
692 if (IS_ERR(filp)) {
693 error = PTR_ERR(filp);
694 goto out_putfd;
695 }
696
697 set_close_on_exec(fd, 1);
698 fd_install(fd, filp);
699 goto out_upsem;
700
Alexander Viro7c7dce92006-01-14 15:29:55 -0500701out:
702 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 mntput(mqueue_mnt);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500704out_putfd:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 put_unused_fd(fd);
706out_err:
707 fd = error;
708out_upsem:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800709 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710out_putname:
711 putname(name);
712 return fd;
713}
714
715asmlinkage long sys_mq_unlink(const char __user *u_name)
716{
717 int err;
718 char *name;
719 struct dentry *dentry;
720 struct inode *inode = NULL;
721
722 name = getname(u_name);
723 if (IS_ERR(name))
724 return PTR_ERR(name);
725
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800726 mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
728 if (IS_ERR(dentry)) {
729 err = PTR_ERR(dentry);
730 goto out_unlock;
731 }
732
733 if (!dentry->d_inode) {
734 err = -ENOENT;
735 goto out_err;
736 }
737
738 inode = dentry->d_inode;
739 if (inode)
740 atomic_inc(&inode->i_count);
741
742 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
743out_err:
744 dput(dentry);
745
746out_unlock:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800747 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 putname(name);
749 if (inode)
750 iput(inode);
751
752 return err;
753}
754
755/* Pipelined send and receive functions.
756 *
757 * If a receiver finds no waiting message, then it registers itself in the
758 * list of waiting receivers. A sender checks that list before adding the new
759 * message into the message array. If there is a waiting receiver, then it
760 * bypasses the message array and directly hands the message over to the
761 * receiver.
762 * The receiver accepts the message and returns without grabbing the queue
763 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
764 * are necessary. The same algorithm is used for sysv semaphores, see
Serge E. Hallyn7b7a3172006-03-28 01:56:23 -0800765 * ipc/sem.c for more details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 *
767 * The same algorithm is used for senders.
768 */
769
770/* pipelined_send() - send a message directly to the task waiting in
771 * sys_mq_timedreceive() (without inserting message into a queue).
772 */
773static inline void pipelined_send(struct mqueue_inode_info *info,
774 struct msg_msg *message,
775 struct ext_wait_queue *receiver)
776{
777 receiver->msg = message;
778 list_del(&receiver->list);
779 receiver->state = STATE_PENDING;
780 wake_up_process(receiver->task);
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700781 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 receiver->state = STATE_READY;
783}
784
785/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
786 * gets its message and put to the queue (we have one free place for sure). */
787static inline void pipelined_receive(struct mqueue_inode_info *info)
788{
789 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
790
791 if (!sender) {
792 /* for poll */
793 wake_up_interruptible(&info->wait_q);
794 return;
795 }
796 msg_insert(sender->msg, info);
797 list_del(&sender->list);
798 sender->state = STATE_PENDING;
799 wake_up_process(sender->task);
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700800 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 sender->state = STATE_READY;
802}
803
804asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
805 size_t msg_len, unsigned int msg_prio,
806 const struct timespec __user *u_abs_timeout)
807{
808 struct file *filp;
809 struct inode *inode;
810 struct ext_wait_queue wait;
811 struct ext_wait_queue *receiver;
812 struct msg_msg *msg_ptr;
813 struct mqueue_inode_info *info;
814 long timeout;
815 int ret;
816
817 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
818 return -EINVAL;
819
820 timeout = prepare_timeout(u_abs_timeout);
821
822 ret = -EBADF;
823 filp = fget(mqdes);
824 if (unlikely(!filp))
825 goto out;
826
827 inode = filp->f_dentry->d_inode;
828 if (unlikely(filp->f_op != &mqueue_file_operations))
829 goto out_fput;
830 info = MQUEUE_I(inode);
831
832 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
833 goto out_fput;
834
835 if (unlikely(msg_len > info->attr.mq_msgsize)) {
836 ret = -EMSGSIZE;
837 goto out_fput;
838 }
839
840 /* First try to allocate memory, before doing anything with
841 * existing queues. */
842 msg_ptr = load_msg(u_msg_ptr, msg_len);
843 if (IS_ERR(msg_ptr)) {
844 ret = PTR_ERR(msg_ptr);
845 goto out_fput;
846 }
847 msg_ptr->m_ts = msg_len;
848 msg_ptr->m_type = msg_prio;
849
850 spin_lock(&info->lock);
851
852 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
853 if (filp->f_flags & O_NONBLOCK) {
854 spin_unlock(&info->lock);
855 ret = -EAGAIN;
856 } else if (unlikely(timeout < 0)) {
857 spin_unlock(&info->lock);
858 ret = timeout;
859 } else {
860 wait.task = current;
861 wait.msg = (void *) msg_ptr;
862 wait.state = STATE_NONE;
863 ret = wq_sleep(info, SEND, timeout, &wait);
864 }
865 if (ret < 0)
866 free_msg(msg_ptr);
867 } else {
868 receiver = wq_get_first_waiter(info, RECV);
869 if (receiver) {
870 pipelined_send(info, msg_ptr, receiver);
871 } else {
872 /* adds message to the queue */
873 msg_insert(msg_ptr, info);
874 __do_notify(info);
875 }
876 inode->i_atime = inode->i_mtime = inode->i_ctime =
877 CURRENT_TIME;
878 spin_unlock(&info->lock);
879 ret = 0;
880 }
881out_fput:
882 fput(filp);
883out:
884 return ret;
885}
886
887asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
888 size_t msg_len, unsigned int __user *u_msg_prio,
889 const struct timespec __user *u_abs_timeout)
890{
891 long timeout;
892 ssize_t ret;
893 struct msg_msg *msg_ptr;
894 struct file *filp;
895 struct inode *inode;
896 struct mqueue_inode_info *info;
897 struct ext_wait_queue wait;
898
899 timeout = prepare_timeout(u_abs_timeout);
900
901 ret = -EBADF;
902 filp = fget(mqdes);
903 if (unlikely(!filp))
904 goto out;
905
906 inode = filp->f_dentry->d_inode;
907 if (unlikely(filp->f_op != &mqueue_file_operations))
908 goto out_fput;
909 info = MQUEUE_I(inode);
910
911 if (unlikely(!(filp->f_mode & FMODE_READ)))
912 goto out_fput;
913
914 /* checks if buffer is big enough */
915 if (unlikely(msg_len < info->attr.mq_msgsize)) {
916 ret = -EMSGSIZE;
917 goto out_fput;
918 }
919
920 spin_lock(&info->lock);
921 if (info->attr.mq_curmsgs == 0) {
922 if (filp->f_flags & O_NONBLOCK) {
923 spin_unlock(&info->lock);
924 ret = -EAGAIN;
925 msg_ptr = NULL;
926 } else if (unlikely(timeout < 0)) {
927 spin_unlock(&info->lock);
928 ret = timeout;
929 msg_ptr = NULL;
930 } else {
931 wait.task = current;
932 wait.state = STATE_NONE;
933 ret = wq_sleep(info, RECV, timeout, &wait);
934 msg_ptr = wait.msg;
935 }
936 } else {
937 msg_ptr = msg_get(info);
938
939 inode->i_atime = inode->i_mtime = inode->i_ctime =
940 CURRENT_TIME;
941
942 /* There is now free space in queue. */
943 pipelined_receive(info);
944 spin_unlock(&info->lock);
945 ret = 0;
946 }
947 if (ret == 0) {
948 ret = msg_ptr->m_ts;
949
950 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
951 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
952 ret = -EFAULT;
953 }
954 free_msg(msg_ptr);
955 }
956out_fput:
957 fput(filp);
958out:
959 return ret;
960}
961
962/*
963 * Notes: the case when user wants us to deregister (with NULL as pointer)
964 * and he isn't currently owner of notification, will be silently discarded.
965 * It isn't explicitly defined in the POSIX.
966 */
967asmlinkage long sys_mq_notify(mqd_t mqdes,
968 const struct sigevent __user *u_notification)
969{
970 int ret;
971 struct file *filp;
972 struct sock *sock;
973 struct inode *inode;
974 struct sigevent notification;
975 struct mqueue_inode_info *info;
976 struct sk_buff *nc;
977
978 nc = NULL;
979 sock = NULL;
980 if (u_notification != NULL) {
981 if (copy_from_user(&notification, u_notification,
982 sizeof(struct sigevent)))
983 return -EFAULT;
984
985 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
986 notification.sigev_notify != SIGEV_SIGNAL &&
987 notification.sigev_notify != SIGEV_THREAD))
988 return -EINVAL;
989 if (notification.sigev_notify == SIGEV_SIGNAL &&
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700990 !valid_signal(notification.sigev_signo)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 return -EINVAL;
992 }
993 if (notification.sigev_notify == SIGEV_THREAD) {
994 /* create the notify skb */
995 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
996 ret = -ENOMEM;
997 if (!nc)
998 goto out;
999 ret = -EFAULT;
1000 if (copy_from_user(nc->data,
1001 notification.sigev_value.sival_ptr,
1002 NOTIFY_COOKIE_LEN)) {
1003 goto out;
1004 }
1005
1006 /* TODO: add a header? */
1007 skb_put(nc, NOTIFY_COOKIE_LEN);
1008 /* and attach it to the socket */
1009retry:
1010 filp = fget(notification.sigev_signo);
1011 ret = -EBADF;
1012 if (!filp)
1013 goto out;
1014 sock = netlink_getsockbyfilp(filp);
1015 fput(filp);
1016 if (IS_ERR(sock)) {
1017 ret = PTR_ERR(sock);
1018 sock = NULL;
1019 goto out;
1020 }
1021
Alexey Kuznetsova70ea992006-02-09 16:40:11 -08001022 ret = netlink_attachskb(sock, nc, 0,
1023 MAX_SCHEDULE_TIMEOUT, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 if (ret == 1)
1025 goto retry;
1026 if (ret) {
1027 sock = NULL;
1028 nc = NULL;
1029 goto out;
1030 }
1031 }
1032 }
1033
1034 ret = -EBADF;
1035 filp = fget(mqdes);
1036 if (!filp)
1037 goto out;
1038
1039 inode = filp->f_dentry->d_inode;
1040 if (unlikely(filp->f_op != &mqueue_file_operations))
1041 goto out_fput;
1042 info = MQUEUE_I(inode);
1043
1044 ret = 0;
1045 spin_lock(&info->lock);
1046 if (u_notification == NULL) {
1047 if (info->notify_owner == current->tgid) {
1048 remove_notification(info);
1049 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1050 }
1051 } else if (info->notify_owner != 0) {
1052 ret = -EBUSY;
1053 } else {
1054 switch (notification.sigev_notify) {
1055 case SIGEV_NONE:
1056 info->notify.sigev_notify = SIGEV_NONE;
1057 break;
1058 case SIGEV_THREAD:
1059 info->notify_sock = sock;
1060 info->notify_cookie = nc;
1061 sock = NULL;
1062 nc = NULL;
1063 info->notify.sigev_notify = SIGEV_THREAD;
1064 break;
1065 case SIGEV_SIGNAL:
1066 info->notify.sigev_signo = notification.sigev_signo;
1067 info->notify.sigev_value = notification.sigev_value;
1068 info->notify.sigev_notify = SIGEV_SIGNAL;
1069 break;
1070 }
1071 info->notify_owner = current->tgid;
1072 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1073 }
1074 spin_unlock(&info->lock);
1075out_fput:
1076 fput(filp);
1077out:
1078 if (sock) {
1079 netlink_detachskb(sock, nc);
1080 } else if (nc) {
1081 dev_kfree_skb(nc);
1082 }
1083 return ret;
1084}
1085
1086asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
1087 const struct mq_attr __user *u_mqstat,
1088 struct mq_attr __user *u_omqstat)
1089{
1090 int ret;
1091 struct mq_attr mqstat, omqstat;
1092 struct file *filp;
1093 struct inode *inode;
1094 struct mqueue_inode_info *info;
1095
1096 if (u_mqstat != NULL) {
1097 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1098 return -EFAULT;
1099 if (mqstat.mq_flags & (~O_NONBLOCK))
1100 return -EINVAL;
1101 }
1102
1103 ret = -EBADF;
1104 filp = fget(mqdes);
1105 if (!filp)
1106 goto out;
1107
1108 inode = filp->f_dentry->d_inode;
1109 if (unlikely(filp->f_op != &mqueue_file_operations))
1110 goto out_fput;
1111 info = MQUEUE_I(inode);
1112
1113 spin_lock(&info->lock);
1114
1115 omqstat = info->attr;
1116 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1117 if (u_mqstat) {
1118 if (mqstat.mq_flags & O_NONBLOCK)
1119 filp->f_flags |= O_NONBLOCK;
1120 else
1121 filp->f_flags &= ~O_NONBLOCK;
1122
1123 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1124 }
1125
1126 spin_unlock(&info->lock);
1127
1128 ret = 0;
1129 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1130 sizeof(struct mq_attr)))
1131 ret = -EFAULT;
1132
1133out_fput:
1134 fput(filp);
1135out:
1136 return ret;
1137}
1138
1139static struct inode_operations mqueue_dir_inode_operations = {
1140 .lookup = simple_lookup,
1141 .create = mqueue_create,
1142 .unlink = mqueue_unlink,
1143};
1144
1145static struct file_operations mqueue_file_operations = {
1146 .flush = mqueue_flush_file,
1147 .poll = mqueue_poll_file,
1148 .read = mqueue_read_file,
1149};
1150
1151static struct super_operations mqueue_super_ops = {
1152 .alloc_inode = mqueue_alloc_inode,
1153 .destroy_inode = mqueue_destroy_inode,
1154 .statfs = simple_statfs,
1155 .delete_inode = mqueue_delete_inode,
1156 .drop_inode = generic_delete_inode,
1157};
1158
1159static struct file_system_type mqueue_fs_type = {
1160 .name = "mqueue",
1161 .get_sb = mqueue_get_sb,
1162 .kill_sb = kill_litter_super,
1163};
1164
1165static int msg_max_limit_min = DFLT_MSGMAX;
1166static int msg_max_limit_max = HARD_MSGMAX;
1167
1168static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
1169static int msg_maxsize_limit_max = INT_MAX;
1170
1171static ctl_table mq_sysctls[] = {
1172 {
1173 .ctl_name = CTL_QUEUESMAX,
1174 .procname = "queues_max",
1175 .data = &queues_max,
1176 .maxlen = sizeof(int),
1177 .mode = 0644,
1178 .proc_handler = &proc_dointvec,
1179 },
1180 {
1181 .ctl_name = CTL_MSGMAX,
1182 .procname = "msg_max",
1183 .data = &msg_max,
1184 .maxlen = sizeof(int),
1185 .mode = 0644,
1186 .proc_handler = &proc_dointvec_minmax,
1187 .extra1 = &msg_max_limit_min,
1188 .extra2 = &msg_max_limit_max,
1189 },
1190 {
1191 .ctl_name = CTL_MSGSIZEMAX,
1192 .procname = "msgsize_max",
1193 .data = &msgsize_max,
1194 .maxlen = sizeof(int),
1195 .mode = 0644,
1196 .proc_handler = &proc_dointvec_minmax,
1197 .extra1 = &msg_maxsize_limit_min,
1198 .extra2 = &msg_maxsize_limit_max,
1199 },
1200 { .ctl_name = 0 }
1201};
1202
1203static ctl_table mq_sysctl_dir[] = {
1204 {
1205 .ctl_name = FS_MQUEUE,
1206 .procname = "mqueue",
1207 .mode = 0555,
1208 .child = mq_sysctls,
1209 },
1210 { .ctl_name = 0 }
1211};
1212
1213static ctl_table mq_sysctl_root[] = {
1214 {
1215 .ctl_name = CTL_FS,
1216 .procname = "fs",
1217 .mode = 0555,
1218 .child = mq_sysctl_dir,
1219 },
1220 { .ctl_name = 0 }
1221};
1222
1223static int __init init_mqueue_fs(void)
1224{
1225 int error;
1226
1227 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1228 sizeof(struct mqueue_inode_info), 0,
1229 SLAB_HWCACHE_ALIGN, init_once, NULL);
1230 if (mqueue_inode_cachep == NULL)
1231 return -ENOMEM;
1232
1233 /* ignore failues - they are not fatal */
1234 mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0);
1235
1236 error = register_filesystem(&mqueue_fs_type);
1237 if (error)
1238 goto out_sysctl;
1239
1240 if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
1241 error = PTR_ERR(mqueue_mnt);
1242 goto out_filesystem;
1243 }
1244
1245 /* internal initialization - not common for vfs */
1246 queues_count = 0;
1247 spin_lock_init(&mq_lock);
1248
1249 return 0;
1250
1251out_filesystem:
1252 unregister_filesystem(&mqueue_fs_type);
1253out_sysctl:
1254 if (mq_sysctl_table)
1255 unregister_sysctl_table(mq_sysctl_table);
1256 if (kmem_cache_destroy(mqueue_inode_cachep)) {
1257 printk(KERN_INFO
1258 "mqueue_inode_cache: not all structures were freed\n");
1259 }
1260 return error;
1261}
1262
1263__initcall(init_mqueue_fs);