2 * POSIX message queues filesystem for Linux.
4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5 * Michal Wronski (michal.wronski@gmail.com)
7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8 * Lockless receive & send, fd based notify:
9 * Manfred Spraul (manfred@colorfullife.com)
11 * Audit: George Wilson (ltcgcw@us.ibm.com)
13 * This file is released under the GPL.
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/vmalloc.h>
28 #include <linux/netlink.h>
29 #include <linux/syscalls.h>
30 #include <linux/audit.h>
31 #include <linux/signal.h>
32 #include <linux/mutex.h>
33 #include <linux/nsproxy.h>
34 #include <linux/pid.h>
35 #include <linux/ipc_namespace.h>
36 #include <linux/user_namespace.h>
37 #include <linux/slab.h>
42 #define MQUEUE_MAGIC 0x19800202
43 #define DIRENT_SIZE 20
44 #define FILENT_SIZE 80
50 #define STATE_PENDING 1
53 struct ext_wait_queue
{ /* queue of sleeping tasks */
54 struct task_struct
*task
;
55 struct list_head list
;
56 struct msg_msg
*msg
; /* ptr of loaded message */
57 int state
; /* one of STATE_* values */
60 struct mqueue_inode_info
{
62 struct inode vfs_inode
;
63 wait_queue_head_t wait_q
;
65 struct msg_msg
**messages
;
68 struct sigevent notify
;
69 struct pid
* notify_owner
;
70 struct user_namespace
*notify_user_ns
;
71 struct user_struct
*user
; /* user who created, for accounting */
72 struct sock
*notify_sock
;
73 struct sk_buff
*notify_cookie
;
75 /* for tasks waiting for free space and messages, respectively */
76 struct ext_wait_queue e_wait_q
[2];
78 unsigned long qsize
; /* size of queue in memory (sum of all msgs) */
81 static const struct inode_operations mqueue_dir_inode_operations
;
82 static const struct file_operations mqueue_file_operations
;
83 static const struct super_operations mqueue_super_ops
;
84 static void remove_notification(struct mqueue_inode_info
*info
);
86 static struct kmem_cache
*mqueue_inode_cachep
;
88 static struct ctl_table_header
* mq_sysctl_table
;
90 static inline struct mqueue_inode_info
*MQUEUE_I(struct inode
*inode
)
92 return container_of(inode
, struct mqueue_inode_info
, vfs_inode
);
96 * This routine should be called with the mq_lock held.
98 static inline struct ipc_namespace
*__get_ns_from_inode(struct inode
*inode
)
100 return get_ipc_ns(inode
->i_sb
->s_fs_info
);
103 static struct ipc_namespace
*get_ns_from_inode(struct inode
*inode
)
105 struct ipc_namespace
*ns
;
108 ns
= __get_ns_from_inode(inode
);
109 spin_unlock(&mq_lock
);
113 static struct inode
*mqueue_get_inode(struct super_block
*sb
,
114 struct ipc_namespace
*ipc_ns
, umode_t mode
,
115 struct mq_attr
*attr
)
117 struct user_struct
*u
= current_user();
121 inode
= new_inode(sb
);
125 inode
->i_ino
= get_next_ino();
126 inode
->i_mode
= mode
;
127 inode
->i_uid
= current_fsuid();
128 inode
->i_gid
= current_fsgid();
129 inode
->i_mtime
= inode
->i_ctime
= inode
->i_atime
= CURRENT_TIME
;
132 struct mqueue_inode_info
*info
;
133 unsigned long mq_bytes
, mq_msg_tblsz
;
135 inode
->i_fop
= &mqueue_file_operations
;
136 inode
->i_size
= FILENT_SIZE
;
137 /* mqueue specific info */
138 info
= MQUEUE_I(inode
);
139 spin_lock_init(&info
->lock
);
140 init_waitqueue_head(&info
->wait_q
);
141 INIT_LIST_HEAD(&info
->e_wait_q
[0].list
);
142 INIT_LIST_HEAD(&info
->e_wait_q
[1].list
);
143 info
->notify_owner
= NULL
;
144 info
->notify_user_ns
= NULL
;
146 info
->user
= NULL
; /* set when all is ok */
147 memset(&info
->attr
, 0, sizeof(info
->attr
));
148 info
->attr
.mq_maxmsg
= min(ipc_ns
->mq_msg_max
, DFLT_MSG
);
149 info
->attr
.mq_msgsize
=
150 min(ipc_ns
->mq_msgsize_max
, DFLT_MSGSIZE
);
152 info
->attr
.mq_maxmsg
= attr
->mq_maxmsg
;
153 info
->attr
.mq_msgsize
= attr
->mq_msgsize
;
155 mq_msg_tblsz
= info
->attr
.mq_maxmsg
* sizeof(struct msg_msg
*);
156 if (mq_msg_tblsz
> KMALLOC_MAX_SIZE
)
157 info
->messages
= vmalloc(mq_msg_tblsz
);
159 info
->messages
= kmalloc(mq_msg_tblsz
, GFP_KERNEL
);
163 mq_bytes
= (mq_msg_tblsz
+
164 (info
->attr
.mq_maxmsg
* info
->attr
.mq_msgsize
));
167 if (u
->mq_bytes
+ mq_bytes
< u
->mq_bytes
||
168 u
->mq_bytes
+ mq_bytes
> rlimit(RLIMIT_MSGQUEUE
)) {
169 spin_unlock(&mq_lock
);
170 /* mqueue_evict_inode() releases info->messages */
174 u
->mq_bytes
+= mq_bytes
;
175 spin_unlock(&mq_lock
);
178 info
->user
= get_uid(u
);
179 } else if (S_ISDIR(mode
)) {
181 /* Some things misbehave if size == 0 on a directory */
182 inode
->i_size
= 2 * DIRENT_SIZE
;
183 inode
->i_op
= &mqueue_dir_inode_operations
;
184 inode
->i_fop
= &simple_dir_operations
;
194 static int mqueue_fill_super(struct super_block
*sb
, void *data
, int silent
)
197 struct ipc_namespace
*ns
= data
;
199 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
200 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
201 sb
->s_magic
= MQUEUE_MAGIC
;
202 sb
->s_op
= &mqueue_super_ops
;
204 inode
= mqueue_get_inode(sb
, ns
, S_IFDIR
| S_ISVTX
| S_IRWXUGO
, NULL
);
206 return PTR_ERR(inode
);
208 sb
->s_root
= d_make_root(inode
);
214 static struct dentry
*mqueue_mount(struct file_system_type
*fs_type
,
215 int flags
, const char *dev_name
,
218 if (!(flags
& MS_KERNMOUNT
))
219 data
= current
->nsproxy
->ipc_ns
;
220 return mount_ns(fs_type
, flags
, data
, mqueue_fill_super
);
223 static void init_once(void *foo
)
225 struct mqueue_inode_info
*p
= (struct mqueue_inode_info
*) foo
;
227 inode_init_once(&p
->vfs_inode
);
230 static struct inode
*mqueue_alloc_inode(struct super_block
*sb
)
232 struct mqueue_inode_info
*ei
;
234 ei
= kmem_cache_alloc(mqueue_inode_cachep
, GFP_KERNEL
);
237 return &ei
->vfs_inode
;
240 static void mqueue_i_callback(struct rcu_head
*head
)
242 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
243 kmem_cache_free(mqueue_inode_cachep
, MQUEUE_I(inode
));
246 static void mqueue_destroy_inode(struct inode
*inode
)
248 call_rcu(&inode
->i_rcu
, mqueue_i_callback
);
251 static void mqueue_evict_inode(struct inode
*inode
)
253 struct mqueue_inode_info
*info
;
254 struct user_struct
*user
;
255 unsigned long mq_bytes
;
257 struct ipc_namespace
*ipc_ns
;
261 if (S_ISDIR(inode
->i_mode
))
264 ipc_ns
= get_ns_from_inode(inode
);
265 info
= MQUEUE_I(inode
);
266 spin_lock(&info
->lock
);
267 for (i
= 0; i
< info
->attr
.mq_curmsgs
; i
++)
268 free_msg(info
->messages
[i
]);
269 if (info
->attr
.mq_maxmsg
* sizeof(struct msg_msg
*) > KMALLOC_MAX_SIZE
)
270 vfree(info
->messages
);
272 kfree(info
->messages
);
273 spin_unlock(&info
->lock
);
275 /* Total amount of bytes accounted for the mqueue */
276 mq_bytes
= info
->attr
.mq_maxmsg
* (sizeof(struct msg_msg
*)
277 + info
->attr
.mq_msgsize
);
281 user
->mq_bytes
-= mq_bytes
;
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.
289 ipc_ns
->mq_queues_count
--;
290 spin_unlock(&mq_lock
);
297 static int mqueue_create(struct inode
*dir
, struct dentry
*dentry
,
298 umode_t mode
, struct nameidata
*nd
)
301 struct mq_attr
*attr
= dentry
->d_fsdata
;
303 struct ipc_namespace
*ipc_ns
;
306 ipc_ns
= __get_ns_from_inode(dir
);
311 if (ipc_ns
->mq_queues_count
>= HARD_QUEUESMAX
||
312 (ipc_ns
->mq_queues_count
>= ipc_ns
->mq_queues_max
&&
313 !capable(CAP_SYS_RESOURCE
))) {
317 ipc_ns
->mq_queues_count
++;
318 spin_unlock(&mq_lock
);
320 inode
= mqueue_get_inode(dir
->i_sb
, ipc_ns
, mode
, attr
);
322 error
= PTR_ERR(inode
);
324 ipc_ns
->mq_queues_count
--;
329 dir
->i_size
+= DIRENT_SIZE
;
330 dir
->i_ctime
= dir
->i_mtime
= dir
->i_atime
= CURRENT_TIME
;
332 d_instantiate(dentry
, inode
);
336 spin_unlock(&mq_lock
);
342 static int mqueue_unlink(struct inode
*dir
, struct dentry
*dentry
)
344 struct inode
*inode
= dentry
->d_inode
;
346 dir
->i_ctime
= dir
->i_mtime
= dir
->i_atime
= CURRENT_TIME
;
347 dir
->i_size
-= DIRENT_SIZE
;
354 * This is routine for system read from queue file.
355 * To avoid mess with doing here some sort of mq_receive we allow
356 * to read only queue size & notification info (the only values
357 * that are interesting from user point of view and aren't accessible
358 * through std routines)
360 static ssize_t
mqueue_read_file(struct file
*filp
, char __user
*u_data
,
361 size_t count
, loff_t
*off
)
363 struct mqueue_inode_info
*info
= MQUEUE_I(filp
->f_path
.dentry
->d_inode
);
364 char buffer
[FILENT_SIZE
];
367 spin_lock(&info
->lock
);
368 snprintf(buffer
, sizeof(buffer
),
369 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
371 info
->notify_owner
? info
->notify
.sigev_notify
: 0,
372 (info
->notify_owner
&&
373 info
->notify
.sigev_notify
== SIGEV_SIGNAL
) ?
374 info
->notify
.sigev_signo
: 0,
375 pid_vnr(info
->notify_owner
));
376 spin_unlock(&info
->lock
);
377 buffer
[sizeof(buffer
)-1] = '\0';
379 ret
= simple_read_from_buffer(u_data
, count
, off
, buffer
,
384 filp
->f_path
.dentry
->d_inode
->i_atime
= filp
->f_path
.dentry
->d_inode
->i_ctime
= CURRENT_TIME
;
388 static int mqueue_flush_file(struct file
*filp
, fl_owner_t id
)
390 struct mqueue_inode_info
*info
= MQUEUE_I(filp
->f_path
.dentry
->d_inode
);
392 spin_lock(&info
->lock
);
393 if (task_tgid(current
) == info
->notify_owner
)
394 remove_notification(info
);
396 spin_unlock(&info
->lock
);
400 static unsigned int mqueue_poll_file(struct file
*filp
, struct poll_table_struct
*poll_tab
)
402 struct mqueue_inode_info
*info
= MQUEUE_I(filp
->f_path
.dentry
->d_inode
);
405 poll_wait(filp
, &info
->wait_q
, poll_tab
);
407 spin_lock(&info
->lock
);
408 if (info
->attr
.mq_curmsgs
)
409 retval
= POLLIN
| POLLRDNORM
;
411 if (info
->attr
.mq_curmsgs
< info
->attr
.mq_maxmsg
)
412 retval
|= POLLOUT
| POLLWRNORM
;
413 spin_unlock(&info
->lock
);
418 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
419 static void wq_add(struct mqueue_inode_info
*info
, int sr
,
420 struct ext_wait_queue
*ewp
)
422 struct ext_wait_queue
*walk
;
426 list_for_each_entry(walk
, &info
->e_wait_q
[sr
].list
, list
) {
427 if (walk
->task
->static_prio
<= current
->static_prio
) {
428 list_add_tail(&ewp
->list
, &walk
->list
);
432 list_add_tail(&ewp
->list
, &info
->e_wait_q
[sr
].list
);
436 * Puts current task to sleep. Caller must hold queue lock. After return
440 static int wq_sleep(struct mqueue_inode_info
*info
, int sr
,
441 ktime_t
*timeout
, struct ext_wait_queue
*ewp
)
446 wq_add(info
, sr
, ewp
);
449 set_current_state(TASK_INTERRUPTIBLE
);
451 spin_unlock(&info
->lock
);
452 time
= schedule_hrtimeout_range_clock(timeout
, 0,
453 HRTIMER_MODE_ABS
, CLOCK_REALTIME
);
455 while (ewp
->state
== STATE_PENDING
)
458 if (ewp
->state
== STATE_READY
) {
462 spin_lock(&info
->lock
);
463 if (ewp
->state
== STATE_READY
) {
467 if (signal_pending(current
)) {
468 retval
= -ERESTARTSYS
;
476 list_del(&ewp
->list
);
478 spin_unlock(&info
->lock
);
484 * Returns waiting task that should be serviced first or NULL if none exists
486 static struct ext_wait_queue
*wq_get_first_waiter(
487 struct mqueue_inode_info
*info
, int sr
)
489 struct list_head
*ptr
;
491 ptr
= info
->e_wait_q
[sr
].list
.prev
;
492 if (ptr
== &info
->e_wait_q
[sr
].list
)
494 return list_entry(ptr
, struct ext_wait_queue
, list
);
497 /* Auxiliary functions to manipulate messages' list */
498 static void msg_insert(struct msg_msg
*ptr
, struct mqueue_inode_info
*info
)
502 k
= info
->attr
.mq_curmsgs
- 1;
503 while (k
>= 0 && info
->messages
[k
]->m_type
>= ptr
->m_type
) {
504 info
->messages
[k
+ 1] = info
->messages
[k
];
507 info
->attr
.mq_curmsgs
++;
508 info
->qsize
+= ptr
->m_ts
;
509 info
->messages
[k
+ 1] = ptr
;
512 static inline struct msg_msg
*msg_get(struct mqueue_inode_info
*info
)
514 info
->qsize
-= info
->messages
[--info
->attr
.mq_curmsgs
]->m_ts
;
515 return info
->messages
[info
->attr
.mq_curmsgs
];
518 static inline void set_cookie(struct sk_buff
*skb
, char code
)
520 ((char*)skb
->data
)[NOTIFY_COOKIE_LEN
-1] = code
;
524 * The next function is only to split too long sys_mq_timedsend
526 static void __do_notify(struct mqueue_inode_info
*info
)
529 * invoked when there is registered process and there isn't process
530 * waiting synchronously for message AND state of queue changed from
531 * empty to not empty. Here we are sure that no one is waiting
533 if (info
->notify_owner
&&
534 info
->attr
.mq_curmsgs
== 1) {
535 struct siginfo sig_i
;
536 switch (info
->notify
.sigev_notify
) {
542 sig_i
.si_signo
= info
->notify
.sigev_signo
;
544 sig_i
.si_code
= SI_MESGQ
;
545 sig_i
.si_value
= info
->notify
.sigev_value
;
546 /* map current pid/uid into info->owner's namespaces */
548 sig_i
.si_pid
= task_tgid_nr_ns(current
,
549 ns_of_pid(info
->notify_owner
));
550 sig_i
.si_uid
= from_kuid_munged(info
->notify_user_ns
, current_uid());
553 kill_pid_info(info
->notify
.sigev_signo
,
554 &sig_i
, info
->notify_owner
);
557 set_cookie(info
->notify_cookie
, NOTIFY_WOKENUP
);
558 netlink_sendskb(info
->notify_sock
, info
->notify_cookie
);
561 /* after notification unregisters process */
562 put_pid(info
->notify_owner
);
563 put_user_ns(info
->notify_user_ns
);
564 info
->notify_owner
= NULL
;
565 info
->notify_user_ns
= NULL
;
567 wake_up(&info
->wait_q
);
570 static int prepare_timeout(const struct timespec __user
*u_abs_timeout
,
571 ktime_t
*expires
, struct timespec
*ts
)
573 if (copy_from_user(ts
, u_abs_timeout
, sizeof(struct timespec
)))
575 if (!timespec_valid(ts
))
578 *expires
= timespec_to_ktime(*ts
);
582 static void remove_notification(struct mqueue_inode_info
*info
)
584 if (info
->notify_owner
!= NULL
&&
585 info
->notify
.sigev_notify
== SIGEV_THREAD
) {
586 set_cookie(info
->notify_cookie
, NOTIFY_REMOVED
);
587 netlink_sendskb(info
->notify_sock
, info
->notify_cookie
);
589 put_pid(info
->notify_owner
);
590 put_user_ns(info
->notify_user_ns
);
591 info
->notify_owner
= NULL
;
592 info
->notify_user_ns
= NULL
;
595 static int mq_attr_ok(struct ipc_namespace
*ipc_ns
, struct mq_attr
*attr
)
597 if (attr
->mq_maxmsg
<= 0 || attr
->mq_msgsize
<= 0)
599 if (capable(CAP_SYS_RESOURCE
)) {
600 if (attr
->mq_maxmsg
> HARD_MSGMAX
||
601 attr
->mq_msgsize
> HARD_MSGSIZEMAX
)
604 if (attr
->mq_maxmsg
> ipc_ns
->mq_msg_max
||
605 attr
->mq_msgsize
> ipc_ns
->mq_msgsize_max
)
608 /* check for overflow */
609 if (attr
->mq_msgsize
> ULONG_MAX
/attr
->mq_maxmsg
)
611 if ((unsigned long)(attr
->mq_maxmsg
* (attr
->mq_msgsize
612 + sizeof (struct msg_msg
*))) <
613 (unsigned long)(attr
->mq_maxmsg
* attr
->mq_msgsize
))
619 * Invoked when creating a new queue via sys_mq_open
621 static struct file
*do_create(struct ipc_namespace
*ipc_ns
, struct dentry
*dir
,
622 struct dentry
*dentry
, int oflag
, umode_t mode
,
623 struct mq_attr
*attr
)
625 const struct cred
*cred
= current_cred();
630 if (!mq_attr_ok(ipc_ns
, attr
)) {
634 /* store for use during create */
635 dentry
->d_fsdata
= attr
;
638 mode
&= ~current_umask();
639 ret
= mnt_want_write(ipc_ns
->mq_mnt
);
642 ret
= vfs_create(dir
->d_inode
, dentry
, mode
, NULL
);
643 dentry
->d_fsdata
= NULL
;
647 result
= dentry_open(dentry
, ipc_ns
->mq_mnt
, oflag
, cred
);
649 * dentry_open() took a persistent mnt_want_write(),
650 * so we can now drop this one.
652 mnt_drop_write(ipc_ns
->mq_mnt
);
656 mnt_drop_write(ipc_ns
->mq_mnt
);
659 mntput(ipc_ns
->mq_mnt
);
663 /* Opens existing queue */
664 static struct file
*do_open(struct ipc_namespace
*ipc_ns
,
665 struct dentry
*dentry
, int oflag
)
668 const struct cred
*cred
= current_cred();
670 static const int oflag2acc
[O_ACCMODE
] = { MAY_READ
, MAY_WRITE
,
671 MAY_READ
| MAY_WRITE
};
673 if ((oflag
& O_ACCMODE
) == (O_RDWR
| O_WRONLY
)) {
678 if (inode_permission(dentry
->d_inode
, oflag2acc
[oflag
& O_ACCMODE
])) {
683 return dentry_open(dentry
, ipc_ns
->mq_mnt
, oflag
, cred
);
687 mntput(ipc_ns
->mq_mnt
);
691 SYSCALL_DEFINE4(mq_open
, const char __user
*, u_name
, int, oflag
, umode_t
, mode
,
692 struct mq_attr __user
*, u_attr
)
694 struct dentry
*dentry
;
699 struct ipc_namespace
*ipc_ns
= current
->nsproxy
->ipc_ns
;
701 if (u_attr
&& copy_from_user(&attr
, u_attr
, sizeof(struct mq_attr
)))
704 audit_mq_open(oflag
, mode
, u_attr
? &attr
: NULL
);
706 if (IS_ERR(name
= getname(u_name
)))
707 return PTR_ERR(name
);
709 fd
= get_unused_fd_flags(O_CLOEXEC
);
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
);
719 mntget(ipc_ns
->mq_mnt
);
721 if (oflag
& O_CREAT
) {
722 if (dentry
->d_inode
) { /* entry already exists */
723 audit_inode(name
, dentry
);
724 if (oflag
& O_EXCL
) {
728 filp
= do_open(ipc_ns
, dentry
, oflag
);
730 filp
= do_create(ipc_ns
, ipc_ns
->mq_mnt
->mnt_root
,
732 u_attr
? &attr
: NULL
);
735 if (!dentry
->d_inode
) {
739 audit_inode(name
, dentry
);
740 filp
= do_open(ipc_ns
, dentry
, oflag
);
744 error
= PTR_ERR(filp
);
748 fd_install(fd
, filp
);
753 mntput(ipc_ns
->mq_mnt
);
758 mutex_unlock(&ipc_ns
->mq_mnt
->mnt_root
->d_inode
->i_mutex
);
764 SYSCALL_DEFINE1(mq_unlink
, const char __user
*, u_name
)
768 struct dentry
*dentry
;
769 struct inode
*inode
= NULL
;
770 struct ipc_namespace
*ipc_ns
= current
->nsproxy
->ipc_ns
;
772 name
= getname(u_name
);
774 return PTR_ERR(name
);
776 mutex_lock_nested(&ipc_ns
->mq_mnt
->mnt_root
->d_inode
->i_mutex
,
778 dentry
= lookup_one_len(name
, ipc_ns
->mq_mnt
->mnt_root
, strlen(name
));
779 if (IS_ERR(dentry
)) {
780 err
= PTR_ERR(dentry
);
784 if (!dentry
->d_inode
) {
789 inode
= dentry
->d_inode
;
792 err
= mnt_want_write(ipc_ns
->mq_mnt
);
795 err
= vfs_unlink(dentry
->d_parent
->d_inode
, dentry
);
796 mnt_drop_write(ipc_ns
->mq_mnt
);
801 mutex_unlock(&ipc_ns
->mq_mnt
->mnt_root
->d_inode
->i_mutex
);
809 /* Pipelined send and receive functions.
811 * If a receiver finds no waiting message, then it registers itself in the
812 * list of waiting receivers. A sender checks that list before adding the new
813 * message into the message array. If there is a waiting receiver, then it
814 * bypasses the message array and directly hands the message over to the
816 * The receiver accepts the message and returns without grabbing the queue
817 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
818 * are necessary. The same algorithm is used for sysv semaphores, see
819 * ipc/sem.c for more details.
821 * The same algorithm is used for senders.
824 /* pipelined_send() - send a message directly to the task waiting in
825 * sys_mq_timedreceive() (without inserting message into a queue).
827 static inline void pipelined_send(struct mqueue_inode_info
*info
,
828 struct msg_msg
*message
,
829 struct ext_wait_queue
*receiver
)
831 receiver
->msg
= message
;
832 list_del(&receiver
->list
);
833 receiver
->state
= STATE_PENDING
;
834 wake_up_process(receiver
->task
);
836 receiver
->state
= STATE_READY
;
839 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
840 * gets its message and put to the queue (we have one free place for sure). */
841 static inline void pipelined_receive(struct mqueue_inode_info
*info
)
843 struct ext_wait_queue
*sender
= wq_get_first_waiter(info
, SEND
);
847 wake_up_interruptible(&info
->wait_q
);
850 msg_insert(sender
->msg
, info
);
851 list_del(&sender
->list
);
852 sender
->state
= STATE_PENDING
;
853 wake_up_process(sender
->task
);
855 sender
->state
= STATE_READY
;
858 SYSCALL_DEFINE5(mq_timedsend
, mqd_t
, mqdes
, const char __user
*, u_msg_ptr
,
859 size_t, msg_len
, unsigned int, msg_prio
,
860 const struct timespec __user
*, u_abs_timeout
)
864 struct ext_wait_queue wait
;
865 struct ext_wait_queue
*receiver
;
866 struct msg_msg
*msg_ptr
;
867 struct mqueue_inode_info
*info
;
868 ktime_t expires
, *timeout
= NULL
;
873 int res
= prepare_timeout(u_abs_timeout
, &expires
, &ts
);
879 if (unlikely(msg_prio
>= (unsigned long) MQ_PRIO_MAX
))
882 audit_mq_sendrecv(mqdes
, msg_len
, msg_prio
, timeout
? &ts
: NULL
);
885 if (unlikely(!filp
)) {
890 inode
= filp
->f_path
.dentry
->d_inode
;
891 if (unlikely(filp
->f_op
!= &mqueue_file_operations
)) {
895 info
= MQUEUE_I(inode
);
896 audit_inode(NULL
, filp
->f_path
.dentry
);
898 if (unlikely(!(filp
->f_mode
& FMODE_WRITE
))) {
903 if (unlikely(msg_len
> info
->attr
.mq_msgsize
)) {
908 /* First try to allocate memory, before doing anything with
909 * existing queues. */
910 msg_ptr
= load_msg(u_msg_ptr
, msg_len
);
911 if (IS_ERR(msg_ptr
)) {
912 ret
= PTR_ERR(msg_ptr
);
915 msg_ptr
->m_ts
= msg_len
;
916 msg_ptr
->m_type
= msg_prio
;
918 spin_lock(&info
->lock
);
920 if (info
->attr
.mq_curmsgs
== info
->attr
.mq_maxmsg
) {
921 if (filp
->f_flags
& O_NONBLOCK
) {
922 spin_unlock(&info
->lock
);
926 wait
.msg
= (void *) msg_ptr
;
927 wait
.state
= STATE_NONE
;
928 ret
= wq_sleep(info
, SEND
, timeout
, &wait
);
933 receiver
= wq_get_first_waiter(info
, RECV
);
935 pipelined_send(info
, msg_ptr
, receiver
);
937 /* adds message to the queue */
938 msg_insert(msg_ptr
, info
);
941 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
=
943 spin_unlock(&info
->lock
);
952 SYSCALL_DEFINE5(mq_timedreceive
, mqd_t
, mqdes
, char __user
*, u_msg_ptr
,
953 size_t, msg_len
, unsigned int __user
*, u_msg_prio
,
954 const struct timespec __user
*, u_abs_timeout
)
957 struct msg_msg
*msg_ptr
;
960 struct mqueue_inode_info
*info
;
961 struct ext_wait_queue wait
;
962 ktime_t expires
, *timeout
= NULL
;
966 int res
= prepare_timeout(u_abs_timeout
, &expires
, &ts
);
972 audit_mq_sendrecv(mqdes
, msg_len
, 0, timeout
? &ts
: NULL
);
975 if (unlikely(!filp
)) {
980 inode
= filp
->f_path
.dentry
->d_inode
;
981 if (unlikely(filp
->f_op
!= &mqueue_file_operations
)) {
985 info
= MQUEUE_I(inode
);
986 audit_inode(NULL
, filp
->f_path
.dentry
);
988 if (unlikely(!(filp
->f_mode
& FMODE_READ
))) {
993 /* checks if buffer is big enough */
994 if (unlikely(msg_len
< info
->attr
.mq_msgsize
)) {
999 spin_lock(&info
->lock
);
1000 if (info
->attr
.mq_curmsgs
== 0) {
1001 if (filp
->f_flags
& O_NONBLOCK
) {
1002 spin_unlock(&info
->lock
);
1005 wait
.task
= current
;
1006 wait
.state
= STATE_NONE
;
1007 ret
= wq_sleep(info
, RECV
, timeout
, &wait
);
1011 msg_ptr
= msg_get(info
);
1013 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
=
1016 /* There is now free space in queue. */
1017 pipelined_receive(info
);
1018 spin_unlock(&info
->lock
);
1022 ret
= msg_ptr
->m_ts
;
1024 if ((u_msg_prio
&& put_user(msg_ptr
->m_type
, u_msg_prio
)) ||
1025 store_msg(u_msg_ptr
, msg_ptr
, msg_ptr
->m_ts
)) {
1037 * Notes: the case when user wants us to deregister (with NULL as pointer)
1038 * and he isn't currently owner of notification, will be silently discarded.
1039 * It isn't explicitly defined in the POSIX.
1041 SYSCALL_DEFINE2(mq_notify
, mqd_t
, mqdes
,
1042 const struct sigevent __user
*, u_notification
)
1047 struct inode
*inode
;
1048 struct sigevent notification
;
1049 struct mqueue_inode_info
*info
;
1052 if (u_notification
) {
1053 if (copy_from_user(¬ification
, u_notification
,
1054 sizeof(struct sigevent
)))
1058 audit_mq_notify(mqdes
, u_notification
? ¬ification
: NULL
);
1062 if (u_notification
!= NULL
) {
1063 if (unlikely(notification
.sigev_notify
!= SIGEV_NONE
&&
1064 notification
.sigev_notify
!= SIGEV_SIGNAL
&&
1065 notification
.sigev_notify
!= SIGEV_THREAD
))
1067 if (notification
.sigev_notify
== SIGEV_SIGNAL
&&
1068 !valid_signal(notification
.sigev_signo
)) {
1071 if (notification
.sigev_notify
== SIGEV_THREAD
) {
1074 /* create the notify skb */
1075 nc
= alloc_skb(NOTIFY_COOKIE_LEN
, GFP_KERNEL
);
1080 if (copy_from_user(nc
->data
,
1081 notification
.sigev_value
.sival_ptr
,
1082 NOTIFY_COOKIE_LEN
)) {
1087 /* TODO: add a header? */
1088 skb_put(nc
, NOTIFY_COOKIE_LEN
);
1089 /* and attach it to the socket */
1091 filp
= fget(notification
.sigev_signo
);
1096 sock
= netlink_getsockbyfilp(filp
);
1099 ret
= PTR_ERR(sock
);
1104 timeo
= MAX_SCHEDULE_TIMEOUT
;
1105 ret
= netlink_attachskb(sock
, nc
, &timeo
, NULL
);
1122 inode
= filp
->f_path
.dentry
->d_inode
;
1123 if (unlikely(filp
->f_op
!= &mqueue_file_operations
)) {
1127 info
= MQUEUE_I(inode
);
1130 spin_lock(&info
->lock
);
1131 if (u_notification
== NULL
) {
1132 if (info
->notify_owner
== task_tgid(current
)) {
1133 remove_notification(info
);
1134 inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
1136 } else if (info
->notify_owner
!= NULL
) {
1139 switch (notification
.sigev_notify
) {
1141 info
->notify
.sigev_notify
= SIGEV_NONE
;
1144 info
->notify_sock
= sock
;
1145 info
->notify_cookie
= nc
;
1148 info
->notify
.sigev_notify
= SIGEV_THREAD
;
1151 info
->notify
.sigev_signo
= notification
.sigev_signo
;
1152 info
->notify
.sigev_value
= notification
.sigev_value
;
1153 info
->notify
.sigev_notify
= SIGEV_SIGNAL
;
1157 info
->notify_owner
= get_pid(task_tgid(current
));
1158 info
->notify_user_ns
= get_user_ns(current_user_ns());
1159 inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
1161 spin_unlock(&info
->lock
);
1166 netlink_detachskb(sock
, nc
);
1173 SYSCALL_DEFINE3(mq_getsetattr
, mqd_t
, mqdes
,
1174 const struct mq_attr __user
*, u_mqstat
,
1175 struct mq_attr __user
*, u_omqstat
)
1178 struct mq_attr mqstat
, omqstat
;
1180 struct inode
*inode
;
1181 struct mqueue_inode_info
*info
;
1183 if (u_mqstat
!= NULL
) {
1184 if (copy_from_user(&mqstat
, u_mqstat
, sizeof(struct mq_attr
)))
1186 if (mqstat
.mq_flags
& (~O_NONBLOCK
))
1196 inode
= filp
->f_path
.dentry
->d_inode
;
1197 if (unlikely(filp
->f_op
!= &mqueue_file_operations
)) {
1201 info
= MQUEUE_I(inode
);
1203 spin_lock(&info
->lock
);
1205 omqstat
= info
->attr
;
1206 omqstat
.mq_flags
= filp
->f_flags
& O_NONBLOCK
;
1208 audit_mq_getsetattr(mqdes
, &mqstat
);
1209 spin_lock(&filp
->f_lock
);
1210 if (mqstat
.mq_flags
& O_NONBLOCK
)
1211 filp
->f_flags
|= O_NONBLOCK
;
1213 filp
->f_flags
&= ~O_NONBLOCK
;
1214 spin_unlock(&filp
->f_lock
);
1216 inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
1219 spin_unlock(&info
->lock
);
1222 if (u_omqstat
!= NULL
&& copy_to_user(u_omqstat
, &omqstat
,
1223 sizeof(struct mq_attr
)))
1232 static const struct inode_operations mqueue_dir_inode_operations
= {
1233 .lookup
= simple_lookup
,
1234 .create
= mqueue_create
,
1235 .unlink
= mqueue_unlink
,
1238 static const struct file_operations mqueue_file_operations
= {
1239 .flush
= mqueue_flush_file
,
1240 .poll
= mqueue_poll_file
,
1241 .read
= mqueue_read_file
,
1242 .llseek
= default_llseek
,
1245 static const struct super_operations mqueue_super_ops
= {
1246 .alloc_inode
= mqueue_alloc_inode
,
1247 .destroy_inode
= mqueue_destroy_inode
,
1248 .evict_inode
= mqueue_evict_inode
,
1249 .statfs
= simple_statfs
,
1252 static struct file_system_type mqueue_fs_type
= {
1254 .mount
= mqueue_mount
,
1255 .kill_sb
= kill_litter_super
,
1258 int mq_init_ns(struct ipc_namespace
*ns
)
1260 ns
->mq_queues_count
= 0;
1261 ns
->mq_queues_max
= DFLT_QUEUESMAX
;
1262 ns
->mq_msg_max
= DFLT_MSGMAX
;
1263 ns
->mq_msgsize_max
= DFLT_MSGSIZEMAX
;
1265 ns
->mq_mnt
= kern_mount_data(&mqueue_fs_type
, ns
);
1266 if (IS_ERR(ns
->mq_mnt
)) {
1267 int err
= PTR_ERR(ns
->mq_mnt
);
1274 void mq_clear_sbinfo(struct ipc_namespace
*ns
)
1276 ns
->mq_mnt
->mnt_sb
->s_fs_info
= NULL
;
1279 void mq_put_mnt(struct ipc_namespace
*ns
)
1281 kern_unmount(ns
->mq_mnt
);
1284 static int __init
init_mqueue_fs(void)
1288 mqueue_inode_cachep
= kmem_cache_create("mqueue_inode_cache",
1289 sizeof(struct mqueue_inode_info
), 0,
1290 SLAB_HWCACHE_ALIGN
, init_once
);
1291 if (mqueue_inode_cachep
== NULL
)
1294 /* ignore failures - they are not fatal */
1295 mq_sysctl_table
= mq_register_sysctl_table();
1297 error
= register_filesystem(&mqueue_fs_type
);
1301 spin_lock_init(&mq_lock
);
1303 error
= mq_init_ns(&init_ipc_ns
);
1305 goto out_filesystem
;
1310 unregister_filesystem(&mqueue_fs_type
);
1312 if (mq_sysctl_table
)
1313 unregister_sysctl_table(mq_sysctl_table
);
1314 kmem_cache_destroy(mqueue_inode_cachep
);
1318 __initcall(init_mqueue_fs
);