blob: 10aa8eeeb112a745b84ef123f9f1641dcf819f5c [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 *
George C. Wilson20ca73b2006-05-24 16:09:55 -050011 * Audit: George Wilson (ltcgcw@us.ibm.com)
12 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * This file is released under the GPL.
14 */
15
Randy.Dunlapc59ede72006-01-11 12:17:46 -080016#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#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>
George C. Wilson20ca73b2006-05-24 16:09:55 -050029#include <linux/audit.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070030#include <linux/signal.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080031#include <linux/mutex.h>
32
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <net/sock.h>
34#include "util.h"
35
36#define MQUEUE_MAGIC 0x19800202
37#define DIRENT_SIZE 20
38#define FILENT_SIZE 80
39
40#define SEND 0
41#define RECV 1
42
43#define STATE_NONE 0
44#define STATE_PENDING 1
45#define STATE_READY 2
46
47/* used by sysctl */
48#define FS_MQUEUE 1
49#define CTL_QUEUESMAX 2
50#define CTL_MSGMAX 3
51#define CTL_MSGSIZEMAX 4
52
53/* default values */
54#define DFLT_QUEUESMAX 256 /* max number of message queues */
55#define DFLT_MSGMAX 10 /* max number of messages in each queue */
56#define HARD_MSGMAX (131072/sizeof(void*))
57#define DFLT_MSGSIZEMAX 8192 /* max message size */
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60struct ext_wait_queue { /* queue of sleeping tasks */
61 struct task_struct *task;
62 struct list_head list;
63 struct msg_msg *msg; /* ptr of loaded message */
64 int state; /* one of STATE_* values */
65};
66
67struct mqueue_inode_info {
68 spinlock_t lock;
69 struct inode vfs_inode;
70 wait_queue_head_t wait_q;
71
72 struct msg_msg **messages;
73 struct mq_attr attr;
74
75 struct sigevent notify;
76 pid_t notify_owner;
Adrian Bunk338cec32005-09-10 00:26:54 -070077 struct user_struct *user; /* user who created, for accounting */
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 struct sock *notify_sock;
79 struct sk_buff *notify_cookie;
80
81 /* for tasks waiting for free space and messages, respectively */
82 struct ext_wait_queue e_wait_q[2];
83
84 unsigned long qsize; /* size of queue in memory (sum of all msgs) */
85};
86
87static struct inode_operations mqueue_dir_inode_operations;
88static struct file_operations mqueue_file_operations;
89static struct super_operations mqueue_super_ops;
90static void remove_notification(struct mqueue_inode_info *info);
91
92static spinlock_t mq_lock;
93static kmem_cache_t *mqueue_inode_cachep;
94static struct vfsmount *mqueue_mnt;
95
96static unsigned int queues_count;
97static unsigned int queues_max = DFLT_QUEUESMAX;
98static unsigned int msg_max = DFLT_MSGMAX;
99static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
100
101static struct ctl_table_header * mq_sysctl_table;
102
103static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
104{
105 return container_of(inode, struct mqueue_inode_info, vfs_inode);
106}
107
108static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
109 struct mq_attr *attr)
110{
111 struct inode *inode;
112
113 inode = new_inode(sb);
114 if (inode) {
115 inode->i_mode = mode;
116 inode->i_uid = current->fsuid;
117 inode->i_gid = current->fsgid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 inode->i_blocks = 0;
119 inode->i_mtime = inode->i_ctime = inode->i_atime =
120 CURRENT_TIME;
121
122 if (S_ISREG(mode)) {
123 struct mqueue_inode_info *info;
124 struct task_struct *p = current;
125 struct user_struct *u = p->user;
126 unsigned long mq_bytes, mq_msg_tblsz;
127
128 inode->i_fop = &mqueue_file_operations;
129 inode->i_size = FILENT_SIZE;
130 /* mqueue specific info */
131 info = MQUEUE_I(inode);
132 spin_lock_init(&info->lock);
133 init_waitqueue_head(&info->wait_q);
134 INIT_LIST_HEAD(&info->e_wait_q[0].list);
135 INIT_LIST_HEAD(&info->e_wait_q[1].list);
136 info->messages = NULL;
137 info->notify_owner = 0;
138 info->qsize = 0;
139 info->user = NULL; /* set when all is ok */
140 memset(&info->attr, 0, sizeof(info->attr));
141 info->attr.mq_maxmsg = DFLT_MSGMAX;
142 info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
143 if (attr) {
144 info->attr.mq_maxmsg = attr->mq_maxmsg;
145 info->attr.mq_msgsize = attr->mq_msgsize;
146 }
147 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
148 mq_bytes = (mq_msg_tblsz +
149 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
150
151 spin_lock(&mq_lock);
152 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
153 u->mq_bytes + mq_bytes >
154 p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
155 spin_unlock(&mq_lock);
156 goto out_inode;
157 }
158 u->mq_bytes += mq_bytes;
159 spin_unlock(&mq_lock);
160
161 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
162 if (!info->messages) {
163 spin_lock(&mq_lock);
164 u->mq_bytes -= mq_bytes;
165 spin_unlock(&mq_lock);
166 goto out_inode;
167 }
168 /* all is ok */
169 info->user = get_uid(u);
170 } else if (S_ISDIR(mode)) {
171 inode->i_nlink++;
172 /* Some things misbehave if size == 0 on a directory */
173 inode->i_size = 2 * DIRENT_SIZE;
174 inode->i_op = &mqueue_dir_inode_operations;
175 inode->i_fop = &simple_dir_operations;
176 }
177 }
178 return inode;
179out_inode:
180 make_bad_inode(inode);
181 iput(inode);
182 return NULL;
183}
184
185static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
186{
187 struct inode *inode;
188
189 sb->s_blocksize = PAGE_CACHE_SIZE;
190 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
191 sb->s_magic = MQUEUE_MAGIC;
192 sb->s_op = &mqueue_super_ops;
193
194 inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
195 if (!inode)
196 return -ENOMEM;
197
198 sb->s_root = d_alloc_root(inode);
199 if (!sb->s_root) {
200 iput(inode);
201 return -ENOMEM;
202 }
203
204 return 0;
205}
206
David Howells454e2392006-06-23 02:02:57 -0700207static int mqueue_get_sb(struct file_system_type *fs_type,
208 int flags, const char *dev_name,
209 void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210{
David Howells454e2392006-06-23 02:02:57 -0700211 return get_sb_single(fs_type, flags, data, mqueue_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212}
213
214static void init_once(void *foo, kmem_cache_t * cachep, unsigned long flags)
215{
216 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
217
218 if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
219 SLAB_CTOR_CONSTRUCTOR)
220 inode_init_once(&p->vfs_inode);
221}
222
223static struct inode *mqueue_alloc_inode(struct super_block *sb)
224{
225 struct mqueue_inode_info *ei;
226
227 ei = kmem_cache_alloc(mqueue_inode_cachep, SLAB_KERNEL);
228 if (!ei)
229 return NULL;
230 return &ei->vfs_inode;
231}
232
233static void mqueue_destroy_inode(struct inode *inode)
234{
235 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
236}
237
238static void mqueue_delete_inode(struct inode *inode)
239{
240 struct mqueue_inode_info *info;
241 struct user_struct *user;
242 unsigned long mq_bytes;
243 int i;
244
245 if (S_ISDIR(inode->i_mode)) {
246 clear_inode(inode);
247 return;
248 }
249 info = MQUEUE_I(inode);
250 spin_lock(&info->lock);
251 for (i = 0; i < info->attr.mq_curmsgs; i++)
252 free_msg(info->messages[i]);
253 kfree(info->messages);
254 spin_unlock(&info->lock);
255
256 clear_inode(inode);
257
258 mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
259 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
260 user = info->user;
261 if (user) {
262 spin_lock(&mq_lock);
263 user->mq_bytes -= mq_bytes;
264 queues_count--;
265 spin_unlock(&mq_lock);
266 free_uid(user);
267 }
268}
269
270static int mqueue_create(struct inode *dir, struct dentry *dentry,
271 int mode, struct nameidata *nd)
272{
273 struct inode *inode;
274 struct mq_attr *attr = dentry->d_fsdata;
275 int error;
276
277 spin_lock(&mq_lock);
278 if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
279 error = -ENOSPC;
280 goto out_lock;
281 }
282 queues_count++;
283 spin_unlock(&mq_lock);
284
285 inode = mqueue_get_inode(dir->i_sb, mode, attr);
286 if (!inode) {
287 error = -ENOMEM;
288 spin_lock(&mq_lock);
289 queues_count--;
290 goto out_lock;
291 }
292
293 dir->i_size += DIRENT_SIZE;
294 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
295
296 d_instantiate(dentry, inode);
297 dget(dentry);
298 return 0;
299out_lock:
300 spin_unlock(&mq_lock);
301 return error;
302}
303
304static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
305{
306 struct inode *inode = dentry->d_inode;
307
308 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
309 dir->i_size -= DIRENT_SIZE;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700310 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 dput(dentry);
312 return 0;
313}
314
315/*
316* This is routine for system read from queue file.
317* To avoid mess with doing here some sort of mq_receive we allow
318* to read only queue size & notification info (the only values
319* that are interesting from user point of view and aren't accessible
320* through std routines)
321*/
322static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
323 size_t count, loff_t * off)
324{
325 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
326 char buffer[FILENT_SIZE];
327 size_t slen;
328 loff_t o;
329
330 if (!count)
331 return 0;
332
333 spin_lock(&info->lock);
334 snprintf(buffer, sizeof(buffer),
335 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
336 info->qsize,
337 info->notify_owner ? info->notify.sigev_notify : 0,
338 (info->notify_owner &&
339 info->notify.sigev_notify == SIGEV_SIGNAL) ?
340 info->notify.sigev_signo : 0,
341 info->notify_owner);
342 spin_unlock(&info->lock);
343 buffer[sizeof(buffer)-1] = '\0';
344 slen = strlen(buffer)+1;
345
346 o = *off;
347 if (o > slen)
348 return 0;
349
350 if (o + count > slen)
351 count = slen - o;
352
353 if (copy_to_user(u_data, buffer + o, count))
354 return -EFAULT;
355
356 *off = o + count;
357 filp->f_dentry->d_inode->i_atime = filp->f_dentry->d_inode->i_ctime = CURRENT_TIME;
358 return count;
359}
360
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -0700361static int mqueue_flush_file(struct file *filp, fl_owner_t id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362{
363 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
364
365 spin_lock(&info->lock);
366 if (current->tgid == info->notify_owner)
367 remove_notification(info);
368
369 spin_unlock(&info->lock);
370 return 0;
371}
372
373static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
374{
375 struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);
376 int retval = 0;
377
378 poll_wait(filp, &info->wait_q, poll_tab);
379
380 spin_lock(&info->lock);
381 if (info->attr.mq_curmsgs)
382 retval = POLLIN | POLLRDNORM;
383
384 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
385 retval |= POLLOUT | POLLWRNORM;
386 spin_unlock(&info->lock);
387
388 return retval;
389}
390
391/* Adds current to info->e_wait_q[sr] before element with smaller prio */
392static void wq_add(struct mqueue_inode_info *info, int sr,
393 struct ext_wait_queue *ewp)
394{
395 struct ext_wait_queue *walk;
396
397 ewp->task = current;
398
399 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
400 if (walk->task->static_prio <= current->static_prio) {
401 list_add_tail(&ewp->list, &walk->list);
402 return;
403 }
404 }
405 list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
406}
407
408/*
409 * Puts current task to sleep. Caller must hold queue lock. After return
410 * lock isn't held.
411 * sr: SEND or RECV
412 */
413static int wq_sleep(struct mqueue_inode_info *info, int sr,
414 long timeout, struct ext_wait_queue *ewp)
415{
416 int retval;
417 signed long time;
418
419 wq_add(info, sr, ewp);
420
421 for (;;) {
422 set_current_state(TASK_INTERRUPTIBLE);
423
424 spin_unlock(&info->lock);
425 time = schedule_timeout(timeout);
426
427 while (ewp->state == STATE_PENDING)
428 cpu_relax();
429
430 if (ewp->state == STATE_READY) {
431 retval = 0;
432 goto out;
433 }
434 spin_lock(&info->lock);
435 if (ewp->state == STATE_READY) {
436 retval = 0;
437 goto out_unlock;
438 }
439 if (signal_pending(current)) {
440 retval = -ERESTARTSYS;
441 break;
442 }
443 if (time == 0) {
444 retval = -ETIMEDOUT;
445 break;
446 }
447 }
448 list_del(&ewp->list);
449out_unlock:
450 spin_unlock(&info->lock);
451out:
452 return retval;
453}
454
455/*
456 * Returns waiting task that should be serviced first or NULL if none exists
457 */
458static struct ext_wait_queue *wq_get_first_waiter(
459 struct mqueue_inode_info *info, int sr)
460{
461 struct list_head *ptr;
462
463 ptr = info->e_wait_q[sr].list.prev;
464 if (ptr == &info->e_wait_q[sr].list)
465 return NULL;
466 return list_entry(ptr, struct ext_wait_queue, list);
467}
468
469/* Auxiliary functions to manipulate messages' list */
470static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
471{
472 int k;
473
474 k = info->attr.mq_curmsgs - 1;
475 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
476 info->messages[k + 1] = info->messages[k];
477 k--;
478 }
479 info->attr.mq_curmsgs++;
480 info->qsize += ptr->m_ts;
481 info->messages[k + 1] = ptr;
482}
483
484static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
485{
486 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
487 return info->messages[info->attr.mq_curmsgs];
488}
489
490static inline void set_cookie(struct sk_buff *skb, char code)
491{
492 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
493}
494
495/*
496 * The next function is only to split too long sys_mq_timedsend
497 */
498static void __do_notify(struct mqueue_inode_info *info)
499{
500 /* notification
501 * invoked when there is registered process and there isn't process
502 * waiting synchronously for message AND state of queue changed from
503 * empty to not empty. Here we are sure that no one is waiting
504 * synchronously. */
505 if (info->notify_owner &&
506 info->attr.mq_curmsgs == 1) {
507 struct siginfo sig_i;
508 switch (info->notify.sigev_notify) {
509 case SIGEV_NONE:
510 break;
511 case SIGEV_SIGNAL:
512 /* sends signal */
513
514 sig_i.si_signo = info->notify.sigev_signo;
515 sig_i.si_errno = 0;
516 sig_i.si_code = SI_MESGQ;
517 sig_i.si_value = info->notify.sigev_value;
518 sig_i.si_pid = current->tgid;
519 sig_i.si_uid = current->uid;
520
521 kill_proc_info(info->notify.sigev_signo,
522 &sig_i, info->notify_owner);
523 break;
524 case SIGEV_THREAD:
525 set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
526 netlink_sendskb(info->notify_sock,
527 info->notify_cookie, 0);
528 break;
529 }
530 /* after notification unregisters process */
531 info->notify_owner = 0;
532 }
533 wake_up(&info->wait_q);
534}
535
536static long prepare_timeout(const struct timespec __user *u_arg)
537{
538 struct timespec ts, nowts;
539 long timeout;
540
541 if (u_arg) {
542 if (unlikely(copy_from_user(&ts, u_arg,
543 sizeof(struct timespec))))
544 return -EFAULT;
545
546 if (unlikely(ts.tv_nsec < 0 || ts.tv_sec < 0
547 || ts.tv_nsec >= NSEC_PER_SEC))
548 return -EINVAL;
549 nowts = CURRENT_TIME;
550 /* first subtract as jiffies can't be too big */
551 ts.tv_sec -= nowts.tv_sec;
552 if (ts.tv_nsec < nowts.tv_nsec) {
553 ts.tv_nsec += NSEC_PER_SEC;
554 ts.tv_sec--;
555 }
556 ts.tv_nsec -= nowts.tv_nsec;
557 if (ts.tv_sec < 0)
558 return 0;
559
560 timeout = timespec_to_jiffies(&ts) + 1;
561 } else
562 return MAX_SCHEDULE_TIMEOUT;
563
564 return timeout;
565}
566
567static void remove_notification(struct mqueue_inode_info *info)
568{
569 if (info->notify_owner != 0 &&
570 info->notify.sigev_notify == SIGEV_THREAD) {
571 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
572 netlink_sendskb(info->notify_sock, info->notify_cookie, 0);
573 }
574 info->notify_owner = 0;
575}
576
577static int mq_attr_ok(struct mq_attr *attr)
578{
579 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
580 return 0;
581 if (capable(CAP_SYS_RESOURCE)) {
582 if (attr->mq_maxmsg > HARD_MSGMAX)
583 return 0;
584 } else {
585 if (attr->mq_maxmsg > msg_max ||
586 attr->mq_msgsize > msgsize_max)
587 return 0;
588 }
589 /* check for overflow */
590 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
591 return 0;
592 if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
593 (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
594 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
595 return 0;
596 return 1;
597}
598
599/*
600 * Invoked when creating a new queue via sys_mq_open
601 */
602static struct file *do_create(struct dentry *dir, struct dentry *dentry,
603 int oflag, mode_t mode, struct mq_attr __user *u_attr)
604{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 struct mq_attr attr;
606 int ret;
607
Alexander Viro7c7dce92006-01-14 15:29:55 -0500608 if (u_attr) {
609 ret = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 if (copy_from_user(&attr, u_attr, sizeof(attr)))
Alexander Viro7c7dce92006-01-14 15:29:55 -0500611 goto out;
612 ret = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 if (!mq_attr_ok(&attr))
Alexander Viro7c7dce92006-01-14 15:29:55 -0500614 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 /* store for use during create */
616 dentry->d_fsdata = &attr;
617 }
618
Krzysztof Benedyczak59175832005-09-27 22:21:36 +0200619 mode &= ~current->fs->umask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 ret = vfs_create(dir->d_inode, dentry, mode, NULL);
621 dentry->d_fsdata = NULL;
622 if (ret)
Alexander Viro7c7dce92006-01-14 15:29:55 -0500623 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Alexander Viro7c7dce92006-01-14 15:29:55 -0500625 return dentry_open(dentry, mqueue_mnt, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626
Alexander Viro7c7dce92006-01-14 15:29:55 -0500627out:
628 dput(dentry);
629 mntput(mqueue_mnt);
630 return ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
633/* Opens existing queue */
634static struct file *do_open(struct dentry *dentry, int oflag)
635{
636static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
637 MAY_READ | MAY_WRITE };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638
Alexander Viro7c7dce92006-01-14 15:29:55 -0500639 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
640 dput(dentry);
641 mntput(mqueue_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 return ERR_PTR(-EINVAL);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500643 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644
Alexander Viro7c7dce92006-01-14 15:29:55 -0500645 if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
646 dput(dentry);
647 mntput(mqueue_mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 return ERR_PTR(-EACCES);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500649 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650
Alexander Viro7c7dce92006-01-14 15:29:55 -0500651 return dentry_open(dentry, mqueue_mnt, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652}
653
654asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
655 struct mq_attr __user *u_attr)
656{
657 struct dentry *dentry;
658 struct file *filp;
659 char *name;
660 int fd, error;
661
George C. Wilson20ca73b2006-05-24 16:09:55 -0500662 error = audit_mq_open(oflag, mode, u_attr);
663 if (error != 0)
664 return error;
665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 if (IS_ERR(name = getname(u_name)))
667 return PTR_ERR(name);
668
669 fd = get_unused_fd();
670 if (fd < 0)
671 goto out_putname;
672
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800673 mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
675 if (IS_ERR(dentry)) {
676 error = PTR_ERR(dentry);
677 goto out_err;
678 }
679 mntget(mqueue_mnt);
680
681 if (oflag & O_CREAT) {
682 if (dentry->d_inode) { /* entry already exists */
Alexander Viro7c7dce92006-01-14 15:29:55 -0500683 error = -EEXIST;
684 if (oflag & O_EXCL)
685 goto out;
686 filp = do_open(dentry, oflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 } else {
688 filp = do_create(mqueue_mnt->mnt_root, dentry,
689 oflag, mode, u_attr);
690 }
Alexander Viro7c7dce92006-01-14 15:29:55 -0500691 } else {
692 error = -ENOENT;
693 if (!dentry->d_inode)
694 goto out;
695 filp = do_open(dentry, oflag);
696 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
698 if (IS_ERR(filp)) {
699 error = PTR_ERR(filp);
700 goto out_putfd;
701 }
702
703 set_close_on_exec(fd, 1);
704 fd_install(fd, filp);
705 goto out_upsem;
706
Alexander Viro7c7dce92006-01-14 15:29:55 -0500707out:
708 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 mntput(mqueue_mnt);
Alexander Viro7c7dce92006-01-14 15:29:55 -0500710out_putfd:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 put_unused_fd(fd);
712out_err:
713 fd = error;
714out_upsem:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800715 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716out_putname:
717 putname(name);
718 return fd;
719}
720
721asmlinkage long sys_mq_unlink(const char __user *u_name)
722{
723 int err;
724 char *name;
725 struct dentry *dentry;
726 struct inode *inode = NULL;
727
728 name = getname(u_name);
729 if (IS_ERR(name))
730 return PTR_ERR(name);
731
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800732 mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
734 if (IS_ERR(dentry)) {
735 err = PTR_ERR(dentry);
736 goto out_unlock;
737 }
738
739 if (!dentry->d_inode) {
740 err = -ENOENT;
741 goto out_err;
742 }
743
744 inode = dentry->d_inode;
745 if (inode)
746 atomic_inc(&inode->i_count);
747
748 err = vfs_unlink(dentry->d_parent->d_inode, dentry);
749out_err:
750 dput(dentry);
751
752out_unlock:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800753 mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 putname(name);
755 if (inode)
756 iput(inode);
757
758 return err;
759}
760
761/* Pipelined send and receive functions.
762 *
763 * If a receiver finds no waiting message, then it registers itself in the
764 * list of waiting receivers. A sender checks that list before adding the new
765 * message into the message array. If there is a waiting receiver, then it
766 * bypasses the message array and directly hands the message over to the
767 * receiver.
768 * The receiver accepts the message and returns without grabbing the queue
769 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
770 * are necessary. The same algorithm is used for sysv semaphores, see
Serge E. Hallyn7b7a3172006-03-28 01:56:23 -0800771 * ipc/sem.c for more details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 *
773 * The same algorithm is used for senders.
774 */
775
776/* pipelined_send() - send a message directly to the task waiting in
777 * sys_mq_timedreceive() (without inserting message into a queue).
778 */
779static inline void pipelined_send(struct mqueue_inode_info *info,
780 struct msg_msg *message,
781 struct ext_wait_queue *receiver)
782{
783 receiver->msg = message;
784 list_del(&receiver->list);
785 receiver->state = STATE_PENDING;
786 wake_up_process(receiver->task);
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700787 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 receiver->state = STATE_READY;
789}
790
791/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
792 * gets its message and put to the queue (we have one free place for sure). */
793static inline void pipelined_receive(struct mqueue_inode_info *info)
794{
795 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
796
797 if (!sender) {
798 /* for poll */
799 wake_up_interruptible(&info->wait_q);
800 return;
801 }
802 msg_insert(sender->msg, info);
803 list_del(&sender->list);
804 sender->state = STATE_PENDING;
805 wake_up_process(sender->task);
akpm@osdl.orgd59dd462005-05-01 08:58:47 -0700806 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 sender->state = STATE_READY;
808}
809
810asmlinkage long sys_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
811 size_t msg_len, unsigned int msg_prio,
812 const struct timespec __user *u_abs_timeout)
813{
814 struct file *filp;
815 struct inode *inode;
816 struct ext_wait_queue wait;
817 struct ext_wait_queue *receiver;
818 struct msg_msg *msg_ptr;
819 struct mqueue_inode_info *info;
820 long timeout;
821 int ret;
822
George C. Wilson20ca73b2006-05-24 16:09:55 -0500823 ret = audit_mq_timedsend(mqdes, msg_len, msg_prio, u_abs_timeout);
824 if (ret != 0)
825 return ret;
826
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
828 return -EINVAL;
829
830 timeout = prepare_timeout(u_abs_timeout);
831
832 ret = -EBADF;
833 filp = fget(mqdes);
834 if (unlikely(!filp))
835 goto out;
836
837 inode = filp->f_dentry->d_inode;
838 if (unlikely(filp->f_op != &mqueue_file_operations))
839 goto out_fput;
840 info = MQUEUE_I(inode);
841
842 if (unlikely(!(filp->f_mode & FMODE_WRITE)))
843 goto out_fput;
844
845 if (unlikely(msg_len > info->attr.mq_msgsize)) {
846 ret = -EMSGSIZE;
847 goto out_fput;
848 }
849
850 /* First try to allocate memory, before doing anything with
851 * existing queues. */
852 msg_ptr = load_msg(u_msg_ptr, msg_len);
853 if (IS_ERR(msg_ptr)) {
854 ret = PTR_ERR(msg_ptr);
855 goto out_fput;
856 }
857 msg_ptr->m_ts = msg_len;
858 msg_ptr->m_type = msg_prio;
859
860 spin_lock(&info->lock);
861
862 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
863 if (filp->f_flags & O_NONBLOCK) {
864 spin_unlock(&info->lock);
865 ret = -EAGAIN;
866 } else if (unlikely(timeout < 0)) {
867 spin_unlock(&info->lock);
868 ret = timeout;
869 } else {
870 wait.task = current;
871 wait.msg = (void *) msg_ptr;
872 wait.state = STATE_NONE;
873 ret = wq_sleep(info, SEND, timeout, &wait);
874 }
875 if (ret < 0)
876 free_msg(msg_ptr);
877 } else {
878 receiver = wq_get_first_waiter(info, RECV);
879 if (receiver) {
880 pipelined_send(info, msg_ptr, receiver);
881 } else {
882 /* adds message to the queue */
883 msg_insert(msg_ptr, info);
884 __do_notify(info);
885 }
886 inode->i_atime = inode->i_mtime = inode->i_ctime =
887 CURRENT_TIME;
888 spin_unlock(&info->lock);
889 ret = 0;
890 }
891out_fput:
892 fput(filp);
893out:
894 return ret;
895}
896
897asmlinkage ssize_t sys_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
898 size_t msg_len, unsigned int __user *u_msg_prio,
899 const struct timespec __user *u_abs_timeout)
900{
901 long timeout;
902 ssize_t ret;
903 struct msg_msg *msg_ptr;
904 struct file *filp;
905 struct inode *inode;
906 struct mqueue_inode_info *info;
907 struct ext_wait_queue wait;
908
George C. Wilson20ca73b2006-05-24 16:09:55 -0500909 ret = audit_mq_timedreceive(mqdes, msg_len, u_msg_prio, u_abs_timeout);
910 if (ret != 0)
911 return ret;
912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 timeout = prepare_timeout(u_abs_timeout);
914
915 ret = -EBADF;
916 filp = fget(mqdes);
917 if (unlikely(!filp))
918 goto out;
919
920 inode = filp->f_dentry->d_inode;
921 if (unlikely(filp->f_op != &mqueue_file_operations))
922 goto out_fput;
923 info = MQUEUE_I(inode);
924
925 if (unlikely(!(filp->f_mode & FMODE_READ)))
926 goto out_fput;
927
928 /* checks if buffer is big enough */
929 if (unlikely(msg_len < info->attr.mq_msgsize)) {
930 ret = -EMSGSIZE;
931 goto out_fput;
932 }
933
934 spin_lock(&info->lock);
935 if (info->attr.mq_curmsgs == 0) {
936 if (filp->f_flags & O_NONBLOCK) {
937 spin_unlock(&info->lock);
938 ret = -EAGAIN;
939 msg_ptr = NULL;
940 } else if (unlikely(timeout < 0)) {
941 spin_unlock(&info->lock);
942 ret = timeout;
943 msg_ptr = NULL;
944 } else {
945 wait.task = current;
946 wait.state = STATE_NONE;
947 ret = wq_sleep(info, RECV, timeout, &wait);
948 msg_ptr = wait.msg;
949 }
950 } else {
951 msg_ptr = msg_get(info);
952
953 inode->i_atime = inode->i_mtime = inode->i_ctime =
954 CURRENT_TIME;
955
956 /* There is now free space in queue. */
957 pipelined_receive(info);
958 spin_unlock(&info->lock);
959 ret = 0;
960 }
961 if (ret == 0) {
962 ret = msg_ptr->m_ts;
963
964 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
965 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
966 ret = -EFAULT;
967 }
968 free_msg(msg_ptr);
969 }
970out_fput:
971 fput(filp);
972out:
973 return ret;
974}
975
976/*
977 * Notes: the case when user wants us to deregister (with NULL as pointer)
978 * and he isn't currently owner of notification, will be silently discarded.
979 * It isn't explicitly defined in the POSIX.
980 */
981asmlinkage long sys_mq_notify(mqd_t mqdes,
982 const struct sigevent __user *u_notification)
983{
984 int ret;
985 struct file *filp;
986 struct sock *sock;
987 struct inode *inode;
988 struct sigevent notification;
989 struct mqueue_inode_info *info;
990 struct sk_buff *nc;
991
George C. Wilson20ca73b2006-05-24 16:09:55 -0500992 ret = audit_mq_notify(mqdes, u_notification);
993 if (ret != 0)
994 return ret;
995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 nc = NULL;
997 sock = NULL;
998 if (u_notification != NULL) {
999 if (copy_from_user(&notification, u_notification,
1000 sizeof(struct sigevent)))
1001 return -EFAULT;
1002
1003 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1004 notification.sigev_notify != SIGEV_SIGNAL &&
1005 notification.sigev_notify != SIGEV_THREAD))
1006 return -EINVAL;
1007 if (notification.sigev_notify == SIGEV_SIGNAL &&
Jesper Juhl7ed20e12005-05-01 08:59:14 -07001008 !valid_signal(notification.sigev_signo)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 return -EINVAL;
1010 }
1011 if (notification.sigev_notify == SIGEV_THREAD) {
1012 /* create the notify skb */
1013 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1014 ret = -ENOMEM;
1015 if (!nc)
1016 goto out;
1017 ret = -EFAULT;
1018 if (copy_from_user(nc->data,
1019 notification.sigev_value.sival_ptr,
1020 NOTIFY_COOKIE_LEN)) {
1021 goto out;
1022 }
1023
1024 /* TODO: add a header? */
1025 skb_put(nc, NOTIFY_COOKIE_LEN);
1026 /* and attach it to the socket */
1027retry:
1028 filp = fget(notification.sigev_signo);
1029 ret = -EBADF;
1030 if (!filp)
1031 goto out;
1032 sock = netlink_getsockbyfilp(filp);
1033 fput(filp);
1034 if (IS_ERR(sock)) {
1035 ret = PTR_ERR(sock);
1036 sock = NULL;
1037 goto out;
1038 }
1039
Alexey Kuznetsova70ea992006-02-09 16:40:11 -08001040 ret = netlink_attachskb(sock, nc, 0,
1041 MAX_SCHEDULE_TIMEOUT, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 if (ret == 1)
1043 goto retry;
1044 if (ret) {
1045 sock = NULL;
1046 nc = NULL;
1047 goto out;
1048 }
1049 }
1050 }
1051
1052 ret = -EBADF;
1053 filp = fget(mqdes);
1054 if (!filp)
1055 goto out;
1056
1057 inode = filp->f_dentry->d_inode;
1058 if (unlikely(filp->f_op != &mqueue_file_operations))
1059 goto out_fput;
1060 info = MQUEUE_I(inode);
1061
1062 ret = 0;
1063 spin_lock(&info->lock);
1064 if (u_notification == NULL) {
1065 if (info->notify_owner == current->tgid) {
1066 remove_notification(info);
1067 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1068 }
1069 } else if (info->notify_owner != 0) {
1070 ret = -EBUSY;
1071 } else {
1072 switch (notification.sigev_notify) {
1073 case SIGEV_NONE:
1074 info->notify.sigev_notify = SIGEV_NONE;
1075 break;
1076 case SIGEV_THREAD:
1077 info->notify_sock = sock;
1078 info->notify_cookie = nc;
1079 sock = NULL;
1080 nc = NULL;
1081 info->notify.sigev_notify = SIGEV_THREAD;
1082 break;
1083 case SIGEV_SIGNAL:
1084 info->notify.sigev_signo = notification.sigev_signo;
1085 info->notify.sigev_value = notification.sigev_value;
1086 info->notify.sigev_notify = SIGEV_SIGNAL;
1087 break;
1088 }
1089 info->notify_owner = current->tgid;
1090 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1091 }
1092 spin_unlock(&info->lock);
1093out_fput:
1094 fput(filp);
1095out:
1096 if (sock) {
1097 netlink_detachskb(sock, nc);
1098 } else if (nc) {
1099 dev_kfree_skb(nc);
1100 }
1101 return ret;
1102}
1103
1104asmlinkage long sys_mq_getsetattr(mqd_t mqdes,
1105 const struct mq_attr __user *u_mqstat,
1106 struct mq_attr __user *u_omqstat)
1107{
1108 int ret;
1109 struct mq_attr mqstat, omqstat;
1110 struct file *filp;
1111 struct inode *inode;
1112 struct mqueue_inode_info *info;
1113
1114 if (u_mqstat != NULL) {
1115 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1116 return -EFAULT;
1117 if (mqstat.mq_flags & (~O_NONBLOCK))
1118 return -EINVAL;
1119 }
1120
1121 ret = -EBADF;
1122 filp = fget(mqdes);
1123 if (!filp)
1124 goto out;
1125
1126 inode = filp->f_dentry->d_inode;
1127 if (unlikely(filp->f_op != &mqueue_file_operations))
1128 goto out_fput;
1129 info = MQUEUE_I(inode);
1130
1131 spin_lock(&info->lock);
1132
1133 omqstat = info->attr;
1134 omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1135 if (u_mqstat) {
George C. Wilson20ca73b2006-05-24 16:09:55 -05001136 ret = audit_mq_getsetattr(mqdes, &mqstat);
1137 if (ret != 0)
1138 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 if (mqstat.mq_flags & O_NONBLOCK)
1140 filp->f_flags |= O_NONBLOCK;
1141 else
1142 filp->f_flags &= ~O_NONBLOCK;
1143
1144 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1145 }
1146
1147 spin_unlock(&info->lock);
1148
1149 ret = 0;
1150 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1151 sizeof(struct mq_attr)))
1152 ret = -EFAULT;
1153
1154out_fput:
1155 fput(filp);
1156out:
1157 return ret;
1158}
1159
1160static struct inode_operations mqueue_dir_inode_operations = {
1161 .lookup = simple_lookup,
1162 .create = mqueue_create,
1163 .unlink = mqueue_unlink,
1164};
1165
1166static struct file_operations mqueue_file_operations = {
1167 .flush = mqueue_flush_file,
1168 .poll = mqueue_poll_file,
1169 .read = mqueue_read_file,
1170};
1171
1172static struct super_operations mqueue_super_ops = {
1173 .alloc_inode = mqueue_alloc_inode,
1174 .destroy_inode = mqueue_destroy_inode,
1175 .statfs = simple_statfs,
1176 .delete_inode = mqueue_delete_inode,
1177 .drop_inode = generic_delete_inode,
1178};
1179
1180static struct file_system_type mqueue_fs_type = {
1181 .name = "mqueue",
1182 .get_sb = mqueue_get_sb,
1183 .kill_sb = kill_litter_super,
1184};
1185
1186static int msg_max_limit_min = DFLT_MSGMAX;
1187static int msg_max_limit_max = HARD_MSGMAX;
1188
1189static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
1190static int msg_maxsize_limit_max = INT_MAX;
1191
1192static ctl_table mq_sysctls[] = {
1193 {
1194 .ctl_name = CTL_QUEUESMAX,
1195 .procname = "queues_max",
1196 .data = &queues_max,
1197 .maxlen = sizeof(int),
1198 .mode = 0644,
1199 .proc_handler = &proc_dointvec,
1200 },
1201 {
1202 .ctl_name = CTL_MSGMAX,
1203 .procname = "msg_max",
1204 .data = &msg_max,
1205 .maxlen = sizeof(int),
1206 .mode = 0644,
1207 .proc_handler = &proc_dointvec_minmax,
1208 .extra1 = &msg_max_limit_min,
1209 .extra2 = &msg_max_limit_max,
1210 },
1211 {
1212 .ctl_name = CTL_MSGSIZEMAX,
1213 .procname = "msgsize_max",
1214 .data = &msgsize_max,
1215 .maxlen = sizeof(int),
1216 .mode = 0644,
1217 .proc_handler = &proc_dointvec_minmax,
1218 .extra1 = &msg_maxsize_limit_min,
1219 .extra2 = &msg_maxsize_limit_max,
1220 },
1221 { .ctl_name = 0 }
1222};
1223
1224static ctl_table mq_sysctl_dir[] = {
1225 {
1226 .ctl_name = FS_MQUEUE,
1227 .procname = "mqueue",
1228 .mode = 0555,
1229 .child = mq_sysctls,
1230 },
1231 { .ctl_name = 0 }
1232};
1233
1234static ctl_table mq_sysctl_root[] = {
1235 {
1236 .ctl_name = CTL_FS,
1237 .procname = "fs",
1238 .mode = 0555,
1239 .child = mq_sysctl_dir,
1240 },
1241 { .ctl_name = 0 }
1242};
1243
1244static int __init init_mqueue_fs(void)
1245{
1246 int error;
1247
1248 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1249 sizeof(struct mqueue_inode_info), 0,
1250 SLAB_HWCACHE_ALIGN, init_once, NULL);
1251 if (mqueue_inode_cachep == NULL)
1252 return -ENOMEM;
1253
1254 /* ignore failues - they are not fatal */
1255 mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0);
1256
1257 error = register_filesystem(&mqueue_fs_type);
1258 if (error)
1259 goto out_sysctl;
1260
1261 if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
1262 error = PTR_ERR(mqueue_mnt);
1263 goto out_filesystem;
1264 }
1265
1266 /* internal initialization - not common for vfs */
1267 queues_count = 0;
1268 spin_lock_init(&mq_lock);
1269
1270 return 0;
1271
1272out_filesystem:
1273 unregister_filesystem(&mqueue_fs_type);
1274out_sysctl:
1275 if (mq_sysctl_table)
1276 unregister_sysctl_table(mq_sysctl_table);
Alexey Dobriyan1a1d92c2006-09-27 01:49:40 -07001277 kmem_cache_destroy(mqueue_inode_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 return error;
1279}
1280
1281__initcall(init_mqueue_fs);