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/fs_context.h>
22 #include <linux/namei.h>
23 #include <linux/sysctl.h>
24 #include <linux/poll.h>
25 #include <linux/mqueue.h>
26 #include <linux/msg.h>
27 #include <linux/skbuff.h>
28 #include <linux/vmalloc.h>
29 #include <linux/netlink.h>
30 #include <linux/syscalls.h>
31 #include <linux/audit.h>
32 #include <linux/signal.h>
33 #include <linux/mutex.h>
34 #include <linux/nsproxy.h>
35 #include <linux/pid.h>
36 #include <linux/ipc_namespace.h>
37 #include <linux/user_namespace.h>
38 #include <linux/slab.h>
39 #include <linux/sched/wake_q.h>
40 #include <linux/sched/signal.h>
41 #include <linux/sched/user.h>
46 struct mqueue_fs_context
{
47 struct ipc_namespace
*ipc_ns
;
50 #define MQUEUE_MAGIC 0x19800202
51 #define DIRENT_SIZE 20
52 #define FILENT_SIZE 80
60 struct posix_msg_tree_node
{
61 struct rb_node rb_node
;
62 struct list_head msg_list
;
66 struct ext_wait_queue
{ /* queue of sleeping tasks */
67 struct task_struct
*task
;
68 struct list_head list
;
69 struct msg_msg
*msg
; /* ptr of loaded message */
70 int state
; /* one of STATE_* values */
73 struct mqueue_inode_info
{
75 struct inode vfs_inode
;
76 wait_queue_head_t wait_q
;
78 struct rb_root msg_tree
;
79 struct posix_msg_tree_node
*node_cache
;
82 struct sigevent notify
;
83 struct pid
*notify_owner
;
84 struct user_namespace
*notify_user_ns
;
85 struct user_struct
*user
; /* user who created, for accounting */
86 struct sock
*notify_sock
;
87 struct sk_buff
*notify_cookie
;
89 /* for tasks waiting for free space and messages, respectively */
90 struct ext_wait_queue e_wait_q
[2];
92 unsigned long qsize
; /* size of queue in memory (sum of all msgs) */
95 static struct file_system_type mqueue_fs_type
;
96 static const struct inode_operations mqueue_dir_inode_operations
;
97 static const struct file_operations mqueue_file_operations
;
98 static const struct super_operations mqueue_super_ops
;
99 static const struct fs_context_operations mqueue_fs_context_ops
;
100 static void remove_notification(struct mqueue_inode_info
*info
);
102 static struct kmem_cache
*mqueue_inode_cachep
;
104 static struct ctl_table_header
*mq_sysctl_table
;
106 static inline struct mqueue_inode_info
*MQUEUE_I(struct inode
*inode
)
108 return container_of(inode
, struct mqueue_inode_info
, vfs_inode
);
112 * This routine should be called with the mq_lock held.
114 static inline struct ipc_namespace
*__get_ns_from_inode(struct inode
*inode
)
116 return get_ipc_ns(inode
->i_sb
->s_fs_info
);
119 static struct ipc_namespace
*get_ns_from_inode(struct inode
*inode
)
121 struct ipc_namespace
*ns
;
124 ns
= __get_ns_from_inode(inode
);
125 spin_unlock(&mq_lock
);
129 /* Auxiliary functions to manipulate messages' list */
130 static int msg_insert(struct msg_msg
*msg
, struct mqueue_inode_info
*info
)
132 struct rb_node
**p
, *parent
= NULL
;
133 struct posix_msg_tree_node
*leaf
;
135 p
= &info
->msg_tree
.rb_node
;
138 leaf
= rb_entry(parent
, struct posix_msg_tree_node
, rb_node
);
140 if (likely(leaf
->priority
== msg
->m_type
))
142 else if (msg
->m_type
< leaf
->priority
)
147 if (info
->node_cache
) {
148 leaf
= info
->node_cache
;
149 info
->node_cache
= NULL
;
151 leaf
= kmalloc(sizeof(*leaf
), GFP_ATOMIC
);
154 INIT_LIST_HEAD(&leaf
->msg_list
);
156 leaf
->priority
= msg
->m_type
;
157 rb_link_node(&leaf
->rb_node
, parent
, p
);
158 rb_insert_color(&leaf
->rb_node
, &info
->msg_tree
);
160 info
->attr
.mq_curmsgs
++;
161 info
->qsize
+= msg
->m_ts
;
162 list_add_tail(&msg
->m_list
, &leaf
->msg_list
);
166 static inline struct msg_msg
*msg_get(struct mqueue_inode_info
*info
)
168 struct rb_node
**p
, *parent
= NULL
;
169 struct posix_msg_tree_node
*leaf
;
173 p
= &info
->msg_tree
.rb_node
;
177 * During insert, low priorities go to the left and high to the
178 * right. On receive, we want the highest priorities first, so
179 * walk all the way to the right.
184 if (info
->attr
.mq_curmsgs
) {
185 pr_warn_once("Inconsistency in POSIX message queue, "
186 "no tree element, but supposedly messages "
188 info
->attr
.mq_curmsgs
= 0;
192 leaf
= rb_entry(parent
, struct posix_msg_tree_node
, rb_node
);
193 if (unlikely(list_empty(&leaf
->msg_list
))) {
194 pr_warn_once("Inconsistency in POSIX message queue, "
195 "empty leaf node but we haven't implemented "
196 "lazy leaf delete!\n");
197 rb_erase(&leaf
->rb_node
, &info
->msg_tree
);
198 if (info
->node_cache
) {
201 info
->node_cache
= leaf
;
205 msg
= list_first_entry(&leaf
->msg_list
,
206 struct msg_msg
, m_list
);
207 list_del(&msg
->m_list
);
208 if (list_empty(&leaf
->msg_list
)) {
209 rb_erase(&leaf
->rb_node
, &info
->msg_tree
);
210 if (info
->node_cache
) {
213 info
->node_cache
= leaf
;
217 info
->attr
.mq_curmsgs
--;
218 info
->qsize
-= msg
->m_ts
;
222 static struct inode
*mqueue_get_inode(struct super_block
*sb
,
223 struct ipc_namespace
*ipc_ns
, umode_t mode
,
224 struct mq_attr
*attr
)
226 struct user_struct
*u
= current_user();
230 inode
= new_inode(sb
);
234 inode
->i_ino
= get_next_ino();
235 inode
->i_mode
= mode
;
236 inode
->i_uid
= current_fsuid();
237 inode
->i_gid
= current_fsgid();
238 inode
->i_mtime
= inode
->i_ctime
= inode
->i_atime
= current_time(inode
);
241 struct mqueue_inode_info
*info
;
242 unsigned long mq_bytes
, mq_treesize
;
244 inode
->i_fop
= &mqueue_file_operations
;
245 inode
->i_size
= FILENT_SIZE
;
246 /* mqueue specific info */
247 info
= MQUEUE_I(inode
);
248 spin_lock_init(&info
->lock
);
249 init_waitqueue_head(&info
->wait_q
);
250 INIT_LIST_HEAD(&info
->e_wait_q
[0].list
);
251 INIT_LIST_HEAD(&info
->e_wait_q
[1].list
);
252 info
->notify_owner
= NULL
;
253 info
->notify_user_ns
= NULL
;
255 info
->user
= NULL
; /* set when all is ok */
256 info
->msg_tree
= RB_ROOT
;
257 info
->node_cache
= NULL
;
258 memset(&info
->attr
, 0, sizeof(info
->attr
));
259 info
->attr
.mq_maxmsg
= min(ipc_ns
->mq_msg_max
,
260 ipc_ns
->mq_msg_default
);
261 info
->attr
.mq_msgsize
= min(ipc_ns
->mq_msgsize_max
,
262 ipc_ns
->mq_msgsize_default
);
264 info
->attr
.mq_maxmsg
= attr
->mq_maxmsg
;
265 info
->attr
.mq_msgsize
= attr
->mq_msgsize
;
268 * We used to allocate a static array of pointers and account
269 * the size of that array as well as one msg_msg struct per
270 * possible message into the queue size. That's no longer
271 * accurate as the queue is now an rbtree and will grow and
272 * shrink depending on usage patterns. We can, however, still
273 * account one msg_msg struct per message, but the nodes are
274 * allocated depending on priority usage, and most programs
275 * only use one, or a handful, of priorities. However, since
276 * this is pinned memory, we need to assume worst case, so
277 * that means the min(mq_maxmsg, max_priorities) * struct
278 * posix_msg_tree_node.
282 if (info
->attr
.mq_maxmsg
<= 0 || info
->attr
.mq_msgsize
<= 0)
284 if (capable(CAP_SYS_RESOURCE
)) {
285 if (info
->attr
.mq_maxmsg
> HARD_MSGMAX
||
286 info
->attr
.mq_msgsize
> HARD_MSGSIZEMAX
)
289 if (info
->attr
.mq_maxmsg
> ipc_ns
->mq_msg_max
||
290 info
->attr
.mq_msgsize
> ipc_ns
->mq_msgsize_max
)
294 /* check for overflow */
295 if (info
->attr
.mq_msgsize
> ULONG_MAX
/info
->attr
.mq_maxmsg
)
297 mq_treesize
= info
->attr
.mq_maxmsg
* sizeof(struct msg_msg
) +
298 min_t(unsigned int, info
->attr
.mq_maxmsg
, MQ_PRIO_MAX
) *
299 sizeof(struct posix_msg_tree_node
);
300 mq_bytes
= info
->attr
.mq_maxmsg
* info
->attr
.mq_msgsize
;
301 if (mq_bytes
+ mq_treesize
< mq_bytes
)
303 mq_bytes
+= mq_treesize
;
305 if (u
->mq_bytes
+ mq_bytes
< u
->mq_bytes
||
306 u
->mq_bytes
+ mq_bytes
> rlimit(RLIMIT_MSGQUEUE
)) {
307 spin_unlock(&mq_lock
);
308 /* mqueue_evict_inode() releases info->messages */
312 u
->mq_bytes
+= mq_bytes
;
313 spin_unlock(&mq_lock
);
316 info
->user
= get_uid(u
);
317 } else if (S_ISDIR(mode
)) {
319 /* Some things misbehave if size == 0 on a directory */
320 inode
->i_size
= 2 * DIRENT_SIZE
;
321 inode
->i_op
= &mqueue_dir_inode_operations
;
322 inode
->i_fop
= &simple_dir_operations
;
332 static int mqueue_fill_super(struct super_block
*sb
, struct fs_context
*fc
)
335 struct ipc_namespace
*ns
= sb
->s_fs_info
;
337 sb
->s_iflags
|= SB_I_NOEXEC
| SB_I_NODEV
;
338 sb
->s_blocksize
= PAGE_SIZE
;
339 sb
->s_blocksize_bits
= PAGE_SHIFT
;
340 sb
->s_magic
= MQUEUE_MAGIC
;
341 sb
->s_op
= &mqueue_super_ops
;
343 inode
= mqueue_get_inode(sb
, ns
, S_IFDIR
| S_ISVTX
| S_IRWXUGO
, NULL
);
345 return PTR_ERR(inode
);
347 sb
->s_root
= d_make_root(inode
);
353 static int mqueue_get_tree(struct fs_context
*fc
)
355 struct mqueue_fs_context
*ctx
= fc
->fs_private
;
357 put_user_ns(fc
->user_ns
);
358 fc
->user_ns
= get_user_ns(ctx
->ipc_ns
->user_ns
);
359 fc
->s_fs_info
= ctx
->ipc_ns
;
360 return vfs_get_super(fc
, vfs_get_keyed_super
, mqueue_fill_super
);
363 static void mqueue_fs_context_free(struct fs_context
*fc
)
365 struct mqueue_fs_context
*ctx
= fc
->fs_private
;
368 put_ipc_ns(ctx
->ipc_ns
);
372 static int mqueue_init_fs_context(struct fs_context
*fc
)
374 struct mqueue_fs_context
*ctx
;
376 ctx
= kzalloc(sizeof(struct mqueue_fs_context
), GFP_KERNEL
);
380 ctx
->ipc_ns
= get_ipc_ns(current
->nsproxy
->ipc_ns
);
381 fc
->fs_private
= ctx
;
382 fc
->ops
= &mqueue_fs_context_ops
;
386 static struct vfsmount
*mq_create_mount(struct ipc_namespace
*ns
)
388 struct mqueue_fs_context
*ctx
;
389 struct fs_context
*fc
;
390 struct vfsmount
*mnt
;
392 fc
= fs_context_for_mount(&mqueue_fs_type
, SB_KERNMOUNT
);
396 ctx
= fc
->fs_private
;
397 put_ipc_ns(ctx
->ipc_ns
);
398 ctx
->ipc_ns
= get_ipc_ns(ns
);
405 static void init_once(void *foo
)
407 struct mqueue_inode_info
*p
= (struct mqueue_inode_info
*) foo
;
409 inode_init_once(&p
->vfs_inode
);
412 static struct inode
*mqueue_alloc_inode(struct super_block
*sb
)
414 struct mqueue_inode_info
*ei
;
416 ei
= kmem_cache_alloc(mqueue_inode_cachep
, GFP_KERNEL
);
419 return &ei
->vfs_inode
;
422 static void mqueue_i_callback(struct rcu_head
*head
)
424 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
425 kmem_cache_free(mqueue_inode_cachep
, MQUEUE_I(inode
));
428 static void mqueue_destroy_inode(struct inode
*inode
)
430 call_rcu(&inode
->i_rcu
, mqueue_i_callback
);
433 static void mqueue_evict_inode(struct inode
*inode
)
435 struct mqueue_inode_info
*info
;
436 struct user_struct
*user
;
437 unsigned long mq_bytes
, mq_treesize
;
438 struct ipc_namespace
*ipc_ns
;
443 if (S_ISDIR(inode
->i_mode
))
446 ipc_ns
= get_ns_from_inode(inode
);
447 info
= MQUEUE_I(inode
);
448 spin_lock(&info
->lock
);
449 while ((msg
= msg_get(info
)) != NULL
)
451 kfree(info
->node_cache
);
452 spin_unlock(&info
->lock
);
454 /* Total amount of bytes accounted for the mqueue */
455 mq_treesize
= info
->attr
.mq_maxmsg
* sizeof(struct msg_msg
) +
456 min_t(unsigned int, info
->attr
.mq_maxmsg
, MQ_PRIO_MAX
) *
457 sizeof(struct posix_msg_tree_node
);
459 mq_bytes
= mq_treesize
+ (info
->attr
.mq_maxmsg
*
460 info
->attr
.mq_msgsize
);
465 user
->mq_bytes
-= mq_bytes
;
467 * get_ns_from_inode() ensures that the
468 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
469 * to which we now hold a reference, or it is NULL.
470 * We can't put it here under mq_lock, though.
473 ipc_ns
->mq_queues_count
--;
474 spin_unlock(&mq_lock
);
481 static int mqueue_create_attr(struct dentry
*dentry
, umode_t mode
, void *arg
)
483 struct inode
*dir
= dentry
->d_parent
->d_inode
;
485 struct mq_attr
*attr
= arg
;
487 struct ipc_namespace
*ipc_ns
;
490 ipc_ns
= __get_ns_from_inode(dir
);
496 if (ipc_ns
->mq_queues_count
>= ipc_ns
->mq_queues_max
&&
497 !capable(CAP_SYS_RESOURCE
)) {
501 ipc_ns
->mq_queues_count
++;
502 spin_unlock(&mq_lock
);
504 inode
= mqueue_get_inode(dir
->i_sb
, ipc_ns
, mode
, attr
);
506 error
= PTR_ERR(inode
);
508 ipc_ns
->mq_queues_count
--;
513 dir
->i_size
+= DIRENT_SIZE
;
514 dir
->i_ctime
= dir
->i_mtime
= dir
->i_atime
= current_time(dir
);
516 d_instantiate(dentry
, inode
);
520 spin_unlock(&mq_lock
);
526 static int mqueue_create(struct inode
*dir
, struct dentry
*dentry
,
527 umode_t mode
, bool excl
)
529 return mqueue_create_attr(dentry
, mode
, NULL
);
532 static int mqueue_unlink(struct inode
*dir
, struct dentry
*dentry
)
534 struct inode
*inode
= d_inode(dentry
);
536 dir
->i_ctime
= dir
->i_mtime
= dir
->i_atime
= current_time(dir
);
537 dir
->i_size
-= DIRENT_SIZE
;
544 * This is routine for system read from queue file.
545 * To avoid mess with doing here some sort of mq_receive we allow
546 * to read only queue size & notification info (the only values
547 * that are interesting from user point of view and aren't accessible
548 * through std routines)
550 static ssize_t
mqueue_read_file(struct file
*filp
, char __user
*u_data
,
551 size_t count
, loff_t
*off
)
553 struct mqueue_inode_info
*info
= MQUEUE_I(file_inode(filp
));
554 char buffer
[FILENT_SIZE
];
557 spin_lock(&info
->lock
);
558 snprintf(buffer
, sizeof(buffer
),
559 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
561 info
->notify_owner
? info
->notify
.sigev_notify
: 0,
562 (info
->notify_owner
&&
563 info
->notify
.sigev_notify
== SIGEV_SIGNAL
) ?
564 info
->notify
.sigev_signo
: 0,
565 pid_vnr(info
->notify_owner
));
566 spin_unlock(&info
->lock
);
567 buffer
[sizeof(buffer
)-1] = '\0';
569 ret
= simple_read_from_buffer(u_data
, count
, off
, buffer
,
574 file_inode(filp
)->i_atime
= file_inode(filp
)->i_ctime
= current_time(file_inode(filp
));
578 static int mqueue_flush_file(struct file
*filp
, fl_owner_t id
)
580 struct mqueue_inode_info
*info
= MQUEUE_I(file_inode(filp
));
582 spin_lock(&info
->lock
);
583 if (task_tgid(current
) == info
->notify_owner
)
584 remove_notification(info
);
586 spin_unlock(&info
->lock
);
590 static __poll_t
mqueue_poll_file(struct file
*filp
, struct poll_table_struct
*poll_tab
)
592 struct mqueue_inode_info
*info
= MQUEUE_I(file_inode(filp
));
595 poll_wait(filp
, &info
->wait_q
, poll_tab
);
597 spin_lock(&info
->lock
);
598 if (info
->attr
.mq_curmsgs
)
599 retval
= EPOLLIN
| EPOLLRDNORM
;
601 if (info
->attr
.mq_curmsgs
< info
->attr
.mq_maxmsg
)
602 retval
|= EPOLLOUT
| EPOLLWRNORM
;
603 spin_unlock(&info
->lock
);
608 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
609 static void wq_add(struct mqueue_inode_info
*info
, int sr
,
610 struct ext_wait_queue
*ewp
)
612 struct ext_wait_queue
*walk
;
616 list_for_each_entry(walk
, &info
->e_wait_q
[sr
].list
, list
) {
617 if (walk
->task
->prio
<= current
->prio
) {
618 list_add_tail(&ewp
->list
, &walk
->list
);
622 list_add_tail(&ewp
->list
, &info
->e_wait_q
[sr
].list
);
626 * Puts current task to sleep. Caller must hold queue lock. After return
630 static int wq_sleep(struct mqueue_inode_info
*info
, int sr
,
631 ktime_t
*timeout
, struct ext_wait_queue
*ewp
)
632 __releases(&info
->lock
)
637 wq_add(info
, sr
, ewp
);
640 __set_current_state(TASK_INTERRUPTIBLE
);
642 spin_unlock(&info
->lock
);
643 time
= schedule_hrtimeout_range_clock(timeout
, 0,
644 HRTIMER_MODE_ABS
, CLOCK_REALTIME
);
646 if (ewp
->state
== STATE_READY
) {
650 spin_lock(&info
->lock
);
651 if (ewp
->state
== STATE_READY
) {
655 if (signal_pending(current
)) {
656 retval
= -ERESTARTSYS
;
664 list_del(&ewp
->list
);
666 spin_unlock(&info
->lock
);
672 * Returns waiting task that should be serviced first or NULL if none exists
674 static struct ext_wait_queue
*wq_get_first_waiter(
675 struct mqueue_inode_info
*info
, int sr
)
677 struct list_head
*ptr
;
679 ptr
= info
->e_wait_q
[sr
].list
.prev
;
680 if (ptr
== &info
->e_wait_q
[sr
].list
)
682 return list_entry(ptr
, struct ext_wait_queue
, list
);
686 static inline void set_cookie(struct sk_buff
*skb
, char code
)
688 ((char *)skb
->data
)[NOTIFY_COOKIE_LEN
-1] = code
;
692 * The next function is only to split too long sys_mq_timedsend
694 static void __do_notify(struct mqueue_inode_info
*info
)
697 * invoked when there is registered process and there isn't process
698 * waiting synchronously for message AND state of queue changed from
699 * empty to not empty. Here we are sure that no one is waiting
701 if (info
->notify_owner
&&
702 info
->attr
.mq_curmsgs
== 1) {
703 struct kernel_siginfo sig_i
;
704 switch (info
->notify
.sigev_notify
) {
710 clear_siginfo(&sig_i
);
711 sig_i
.si_signo
= info
->notify
.sigev_signo
;
713 sig_i
.si_code
= SI_MESGQ
;
714 sig_i
.si_value
= info
->notify
.sigev_value
;
715 /* map current pid/uid into info->owner's namespaces */
717 sig_i
.si_pid
= task_tgid_nr_ns(current
,
718 ns_of_pid(info
->notify_owner
));
719 sig_i
.si_uid
= from_kuid_munged(info
->notify_user_ns
, current_uid());
722 kill_pid_info(info
->notify
.sigev_signo
,
723 &sig_i
, info
->notify_owner
);
726 set_cookie(info
->notify_cookie
, NOTIFY_WOKENUP
);
727 netlink_sendskb(info
->notify_sock
, info
->notify_cookie
);
730 /* after notification unregisters process */
731 put_pid(info
->notify_owner
);
732 put_user_ns(info
->notify_user_ns
);
733 info
->notify_owner
= NULL
;
734 info
->notify_user_ns
= NULL
;
736 wake_up(&info
->wait_q
);
739 static int prepare_timeout(const struct __kernel_timespec __user
*u_abs_timeout
,
740 struct timespec64
*ts
)
742 if (get_timespec64(ts
, u_abs_timeout
))
744 if (!timespec64_valid(ts
))
749 static void remove_notification(struct mqueue_inode_info
*info
)
751 if (info
->notify_owner
!= NULL
&&
752 info
->notify
.sigev_notify
== SIGEV_THREAD
) {
753 set_cookie(info
->notify_cookie
, NOTIFY_REMOVED
);
754 netlink_sendskb(info
->notify_sock
, info
->notify_cookie
);
756 put_pid(info
->notify_owner
);
757 put_user_ns(info
->notify_user_ns
);
758 info
->notify_owner
= NULL
;
759 info
->notify_user_ns
= NULL
;
762 static int prepare_open(struct dentry
*dentry
, int oflag
, int ro
,
763 umode_t mode
, struct filename
*name
,
764 struct mq_attr
*attr
)
766 static const int oflag2acc
[O_ACCMODE
] = { MAY_READ
, MAY_WRITE
,
767 MAY_READ
| MAY_WRITE
};
770 if (d_really_is_negative(dentry
)) {
771 if (!(oflag
& O_CREAT
))
775 audit_inode_parent_hidden(name
, dentry
->d_parent
);
776 return vfs_mkobj(dentry
, mode
& ~current_umask(),
777 mqueue_create_attr
, attr
);
779 /* it already existed */
780 audit_inode(name
, dentry
, 0);
781 if ((oflag
& (O_CREAT
|O_EXCL
)) == (O_CREAT
|O_EXCL
))
783 if ((oflag
& O_ACCMODE
) == (O_RDWR
| O_WRONLY
))
785 acc
= oflag2acc
[oflag
& O_ACCMODE
];
786 return inode_permission(d_inode(dentry
), acc
);
789 static int do_mq_open(const char __user
*u_name
, int oflag
, umode_t mode
,
790 struct mq_attr
*attr
)
792 struct vfsmount
*mnt
= current
->nsproxy
->ipc_ns
->mq_mnt
;
793 struct dentry
*root
= mnt
->mnt_root
;
794 struct filename
*name
;
799 audit_mq_open(oflag
, mode
, attr
);
801 if (IS_ERR(name
= getname(u_name
)))
802 return PTR_ERR(name
);
804 fd
= get_unused_fd_flags(O_CLOEXEC
);
808 ro
= mnt_want_write(mnt
); /* we'll drop it in any case */
809 inode_lock(d_inode(root
));
810 path
.dentry
= lookup_one_len(name
->name
, root
, strlen(name
->name
));
811 if (IS_ERR(path
.dentry
)) {
812 error
= PTR_ERR(path
.dentry
);
815 path
.mnt
= mntget(mnt
);
816 error
= prepare_open(path
.dentry
, oflag
, ro
, mode
, name
, attr
);
818 struct file
*file
= dentry_open(&path
, oflag
, current_cred());
820 fd_install(fd
, file
);
822 error
= PTR_ERR(file
);
830 inode_unlock(d_inode(root
));
838 SYSCALL_DEFINE4(mq_open
, const char __user
*, u_name
, int, oflag
, umode_t
, mode
,
839 struct mq_attr __user
*, u_attr
)
842 if (u_attr
&& copy_from_user(&attr
, u_attr
, sizeof(struct mq_attr
)))
845 return do_mq_open(u_name
, oflag
, mode
, u_attr
? &attr
: NULL
);
848 SYSCALL_DEFINE1(mq_unlink
, const char __user
*, u_name
)
851 struct filename
*name
;
852 struct dentry
*dentry
;
853 struct inode
*inode
= NULL
;
854 struct ipc_namespace
*ipc_ns
= current
->nsproxy
->ipc_ns
;
855 struct vfsmount
*mnt
= ipc_ns
->mq_mnt
;
857 name
= getname(u_name
);
859 return PTR_ERR(name
);
861 audit_inode_parent_hidden(name
, mnt
->mnt_root
);
862 err
= mnt_want_write(mnt
);
865 inode_lock_nested(d_inode(mnt
->mnt_root
), I_MUTEX_PARENT
);
866 dentry
= lookup_one_len(name
->name
, mnt
->mnt_root
,
868 if (IS_ERR(dentry
)) {
869 err
= PTR_ERR(dentry
);
873 inode
= d_inode(dentry
);
878 err
= vfs_unlink(d_inode(dentry
->d_parent
), dentry
, NULL
);
883 inode_unlock(d_inode(mnt
->mnt_root
));
893 /* Pipelined send and receive functions.
895 * If a receiver finds no waiting message, then it registers itself in the
896 * list of waiting receivers. A sender checks that list before adding the new
897 * message into the message array. If there is a waiting receiver, then it
898 * bypasses the message array and directly hands the message over to the
899 * receiver. The receiver accepts the message and returns without grabbing the
902 * - Set pointer to message.
903 * - Queue the receiver task for later wakeup (without the info->lock).
904 * - Update its state to STATE_READY. Now the receiver can continue.
905 * - Wake up the process after the lock is dropped. Should the process wake up
906 * before this wakeup (due to a timeout or a signal) it will either see
907 * STATE_READY and continue or acquire the lock to check the state again.
909 * The same algorithm is used for senders.
912 /* pipelined_send() - send a message directly to the task waiting in
913 * sys_mq_timedreceive() (without inserting message into a queue).
915 static inline void pipelined_send(struct wake_q_head
*wake_q
,
916 struct mqueue_inode_info
*info
,
917 struct msg_msg
*message
,
918 struct ext_wait_queue
*receiver
)
920 receiver
->msg
= message
;
921 list_del(&receiver
->list
);
922 wake_q_add(wake_q
, receiver
->task
);
924 * Rely on the implicit cmpxchg barrier from wake_q_add such
925 * that we can ensure that updating receiver->state is the last
926 * write operation: As once set, the receiver can continue,
927 * and if we don't have the reference count from the wake_q,
928 * yet, at that point we can later have a use-after-free
929 * condition and bogus wakeup.
931 receiver
->state
= STATE_READY
;
934 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
935 * gets its message and put to the queue (we have one free place for sure). */
936 static inline void pipelined_receive(struct wake_q_head
*wake_q
,
937 struct mqueue_inode_info
*info
)
939 struct ext_wait_queue
*sender
= wq_get_first_waiter(info
, SEND
);
943 wake_up_interruptible(&info
->wait_q
);
946 if (msg_insert(sender
->msg
, info
))
949 list_del(&sender
->list
);
950 wake_q_add(wake_q
, sender
->task
);
951 sender
->state
= STATE_READY
;
954 static int do_mq_timedsend(mqd_t mqdes
, const char __user
*u_msg_ptr
,
955 size_t msg_len
, unsigned int msg_prio
,
956 struct timespec64
*ts
)
960 struct ext_wait_queue wait
;
961 struct ext_wait_queue
*receiver
;
962 struct msg_msg
*msg_ptr
;
963 struct mqueue_inode_info
*info
;
964 ktime_t expires
, *timeout
= NULL
;
965 struct posix_msg_tree_node
*new_leaf
= NULL
;
967 DEFINE_WAKE_Q(wake_q
);
969 if (unlikely(msg_prio
>= (unsigned long) MQ_PRIO_MAX
))
973 expires
= timespec64_to_ktime(*ts
);
977 audit_mq_sendrecv(mqdes
, msg_len
, msg_prio
, ts
);
980 if (unlikely(!f
.file
)) {
985 inode
= file_inode(f
.file
);
986 if (unlikely(f
.file
->f_op
!= &mqueue_file_operations
)) {
990 info
= MQUEUE_I(inode
);
993 if (unlikely(!(f
.file
->f_mode
& FMODE_WRITE
))) {
998 if (unlikely(msg_len
> info
->attr
.mq_msgsize
)) {
1003 /* First try to allocate memory, before doing anything with
1004 * existing queues. */
1005 msg_ptr
= load_msg(u_msg_ptr
, msg_len
);
1006 if (IS_ERR(msg_ptr
)) {
1007 ret
= PTR_ERR(msg_ptr
);
1010 msg_ptr
->m_ts
= msg_len
;
1011 msg_ptr
->m_type
= msg_prio
;
1014 * msg_insert really wants us to have a valid, spare node struct so
1015 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1016 * fall back to that if necessary.
1018 if (!info
->node_cache
)
1019 new_leaf
= kmalloc(sizeof(*new_leaf
), GFP_KERNEL
);
1021 spin_lock(&info
->lock
);
1023 if (!info
->node_cache
&& new_leaf
) {
1024 /* Save our speculative allocation into the cache */
1025 INIT_LIST_HEAD(&new_leaf
->msg_list
);
1026 info
->node_cache
= new_leaf
;
1032 if (info
->attr
.mq_curmsgs
== info
->attr
.mq_maxmsg
) {
1033 if (f
.file
->f_flags
& O_NONBLOCK
) {
1036 wait
.task
= current
;
1037 wait
.msg
= (void *) msg_ptr
;
1038 wait
.state
= STATE_NONE
;
1039 ret
= wq_sleep(info
, SEND
, timeout
, &wait
);
1041 * wq_sleep must be called with info->lock held, and
1042 * returns with the lock released
1047 receiver
= wq_get_first_waiter(info
, RECV
);
1049 pipelined_send(&wake_q
, info
, msg_ptr
, receiver
);
1051 /* adds message to the queue */
1052 ret
= msg_insert(msg_ptr
, info
);
1057 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
=
1058 current_time(inode
);
1061 spin_unlock(&info
->lock
);
1072 static int do_mq_timedreceive(mqd_t mqdes
, char __user
*u_msg_ptr
,
1073 size_t msg_len
, unsigned int __user
*u_msg_prio
,
1074 struct timespec64
*ts
)
1077 struct msg_msg
*msg_ptr
;
1079 struct inode
*inode
;
1080 struct mqueue_inode_info
*info
;
1081 struct ext_wait_queue wait
;
1082 ktime_t expires
, *timeout
= NULL
;
1083 struct posix_msg_tree_node
*new_leaf
= NULL
;
1086 expires
= timespec64_to_ktime(*ts
);
1090 audit_mq_sendrecv(mqdes
, msg_len
, 0, ts
);
1093 if (unlikely(!f
.file
)) {
1098 inode
= file_inode(f
.file
);
1099 if (unlikely(f
.file
->f_op
!= &mqueue_file_operations
)) {
1103 info
= MQUEUE_I(inode
);
1106 if (unlikely(!(f
.file
->f_mode
& FMODE_READ
))) {
1111 /* checks if buffer is big enough */
1112 if (unlikely(msg_len
< info
->attr
.mq_msgsize
)) {
1118 * msg_insert really wants us to have a valid, spare node struct so
1119 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1120 * fall back to that if necessary.
1122 if (!info
->node_cache
)
1123 new_leaf
= kmalloc(sizeof(*new_leaf
), GFP_KERNEL
);
1125 spin_lock(&info
->lock
);
1127 if (!info
->node_cache
&& new_leaf
) {
1128 /* Save our speculative allocation into the cache */
1129 INIT_LIST_HEAD(&new_leaf
->msg_list
);
1130 info
->node_cache
= new_leaf
;
1135 if (info
->attr
.mq_curmsgs
== 0) {
1136 if (f
.file
->f_flags
& O_NONBLOCK
) {
1137 spin_unlock(&info
->lock
);
1140 wait
.task
= current
;
1141 wait
.state
= STATE_NONE
;
1142 ret
= wq_sleep(info
, RECV
, timeout
, &wait
);
1146 DEFINE_WAKE_Q(wake_q
);
1148 msg_ptr
= msg_get(info
);
1150 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
=
1151 current_time(inode
);
1153 /* There is now free space in queue. */
1154 pipelined_receive(&wake_q
, info
);
1155 spin_unlock(&info
->lock
);
1160 ret
= msg_ptr
->m_ts
;
1162 if ((u_msg_prio
&& put_user(msg_ptr
->m_type
, u_msg_prio
)) ||
1163 store_msg(u_msg_ptr
, msg_ptr
, msg_ptr
->m_ts
)) {
1174 SYSCALL_DEFINE5(mq_timedsend
, mqd_t
, mqdes
, const char __user
*, u_msg_ptr
,
1175 size_t, msg_len
, unsigned int, msg_prio
,
1176 const struct __kernel_timespec __user
*, u_abs_timeout
)
1178 struct timespec64 ts
, *p
= NULL
;
1179 if (u_abs_timeout
) {
1180 int res
= prepare_timeout(u_abs_timeout
, &ts
);
1185 return do_mq_timedsend(mqdes
, u_msg_ptr
, msg_len
, msg_prio
, p
);
1188 SYSCALL_DEFINE5(mq_timedreceive
, mqd_t
, mqdes
, char __user
*, u_msg_ptr
,
1189 size_t, msg_len
, unsigned int __user
*, u_msg_prio
,
1190 const struct __kernel_timespec __user
*, u_abs_timeout
)
1192 struct timespec64 ts
, *p
= NULL
;
1193 if (u_abs_timeout
) {
1194 int res
= prepare_timeout(u_abs_timeout
, &ts
);
1199 return do_mq_timedreceive(mqdes
, u_msg_ptr
, msg_len
, u_msg_prio
, p
);
1203 * Notes: the case when user wants us to deregister (with NULL as pointer)
1204 * and he isn't currently owner of notification, will be silently discarded.
1205 * It isn't explicitly defined in the POSIX.
1207 static int do_mq_notify(mqd_t mqdes
, const struct sigevent
*notification
)
1212 struct inode
*inode
;
1213 struct mqueue_inode_info
*info
;
1216 audit_mq_notify(mqdes
, notification
);
1220 if (notification
!= NULL
) {
1221 if (unlikely(notification
->sigev_notify
!= SIGEV_NONE
&&
1222 notification
->sigev_notify
!= SIGEV_SIGNAL
&&
1223 notification
->sigev_notify
!= SIGEV_THREAD
))
1225 if (notification
->sigev_notify
== SIGEV_SIGNAL
&&
1226 !valid_signal(notification
->sigev_signo
)) {
1229 if (notification
->sigev_notify
== SIGEV_THREAD
) {
1232 /* create the notify skb */
1233 nc
= alloc_skb(NOTIFY_COOKIE_LEN
, GFP_KERNEL
);
1238 if (copy_from_user(nc
->data
,
1239 notification
->sigev_value
.sival_ptr
,
1240 NOTIFY_COOKIE_LEN
)) {
1245 /* TODO: add a header? */
1246 skb_put(nc
, NOTIFY_COOKIE_LEN
);
1247 /* and attach it to the socket */
1249 f
= fdget(notification
->sigev_signo
);
1254 sock
= netlink_getsockbyfilp(f
.file
);
1257 ret
= PTR_ERR(sock
);
1262 timeo
= MAX_SCHEDULE_TIMEOUT
;
1263 ret
= netlink_attachskb(sock
, nc
, &timeo
, NULL
);
1282 inode
= file_inode(f
.file
);
1283 if (unlikely(f
.file
->f_op
!= &mqueue_file_operations
)) {
1287 info
= MQUEUE_I(inode
);
1290 spin_lock(&info
->lock
);
1291 if (notification
== NULL
) {
1292 if (info
->notify_owner
== task_tgid(current
)) {
1293 remove_notification(info
);
1294 inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
1296 } else if (info
->notify_owner
!= NULL
) {
1299 switch (notification
->sigev_notify
) {
1301 info
->notify
.sigev_notify
= SIGEV_NONE
;
1304 info
->notify_sock
= sock
;
1305 info
->notify_cookie
= nc
;
1308 info
->notify
.sigev_notify
= SIGEV_THREAD
;
1311 info
->notify
.sigev_signo
= notification
->sigev_signo
;
1312 info
->notify
.sigev_value
= notification
->sigev_value
;
1313 info
->notify
.sigev_notify
= SIGEV_SIGNAL
;
1317 info
->notify_owner
= get_pid(task_tgid(current
));
1318 info
->notify_user_ns
= get_user_ns(current_user_ns());
1319 inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
1321 spin_unlock(&info
->lock
);
1326 netlink_detachskb(sock
, nc
);
1333 SYSCALL_DEFINE2(mq_notify
, mqd_t
, mqdes
,
1334 const struct sigevent __user
*, u_notification
)
1336 struct sigevent n
, *p
= NULL
;
1337 if (u_notification
) {
1338 if (copy_from_user(&n
, u_notification
, sizeof(struct sigevent
)))
1342 return do_mq_notify(mqdes
, p
);
1345 static int do_mq_getsetattr(int mqdes
, struct mq_attr
*new, struct mq_attr
*old
)
1348 struct inode
*inode
;
1349 struct mqueue_inode_info
*info
;
1351 if (new && (new->mq_flags
& (~O_NONBLOCK
)))
1358 if (unlikely(f
.file
->f_op
!= &mqueue_file_operations
)) {
1363 inode
= file_inode(f
.file
);
1364 info
= MQUEUE_I(inode
);
1366 spin_lock(&info
->lock
);
1370 old
->mq_flags
= f
.file
->f_flags
& O_NONBLOCK
;
1373 audit_mq_getsetattr(mqdes
, new);
1374 spin_lock(&f
.file
->f_lock
);
1375 if (new->mq_flags
& O_NONBLOCK
)
1376 f
.file
->f_flags
|= O_NONBLOCK
;
1378 f
.file
->f_flags
&= ~O_NONBLOCK
;
1379 spin_unlock(&f
.file
->f_lock
);
1381 inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
1384 spin_unlock(&info
->lock
);
1389 SYSCALL_DEFINE3(mq_getsetattr
, mqd_t
, mqdes
,
1390 const struct mq_attr __user
*, u_mqstat
,
1391 struct mq_attr __user
*, u_omqstat
)
1394 struct mq_attr mqstat
, omqstat
;
1395 struct mq_attr
*new = NULL
, *old
= NULL
;
1399 if (copy_from_user(new, u_mqstat
, sizeof(struct mq_attr
)))
1405 ret
= do_mq_getsetattr(mqdes
, new, old
);
1409 if (copy_to_user(u_omqstat
, old
, sizeof(struct mq_attr
)))
1414 #ifdef CONFIG_COMPAT
1416 struct compat_mq_attr
{
1417 compat_long_t mq_flags
; /* message queue flags */
1418 compat_long_t mq_maxmsg
; /* maximum number of messages */
1419 compat_long_t mq_msgsize
; /* maximum message size */
1420 compat_long_t mq_curmsgs
; /* number of messages currently queued */
1421 compat_long_t __reserved
[4]; /* ignored for input, zeroed for output */
1424 static inline int get_compat_mq_attr(struct mq_attr
*attr
,
1425 const struct compat_mq_attr __user
*uattr
)
1427 struct compat_mq_attr v
;
1429 if (copy_from_user(&v
, uattr
, sizeof(*uattr
)))
1432 memset(attr
, 0, sizeof(*attr
));
1433 attr
->mq_flags
= v
.mq_flags
;
1434 attr
->mq_maxmsg
= v
.mq_maxmsg
;
1435 attr
->mq_msgsize
= v
.mq_msgsize
;
1436 attr
->mq_curmsgs
= v
.mq_curmsgs
;
1440 static inline int put_compat_mq_attr(const struct mq_attr
*attr
,
1441 struct compat_mq_attr __user
*uattr
)
1443 struct compat_mq_attr v
;
1445 memset(&v
, 0, sizeof(v
));
1446 v
.mq_flags
= attr
->mq_flags
;
1447 v
.mq_maxmsg
= attr
->mq_maxmsg
;
1448 v
.mq_msgsize
= attr
->mq_msgsize
;
1449 v
.mq_curmsgs
= attr
->mq_curmsgs
;
1450 if (copy_to_user(uattr
, &v
, sizeof(*uattr
)))
1455 COMPAT_SYSCALL_DEFINE4(mq_open
, const char __user
*, u_name
,
1456 int, oflag
, compat_mode_t
, mode
,
1457 struct compat_mq_attr __user
*, u_attr
)
1459 struct mq_attr attr
, *p
= NULL
;
1460 if (u_attr
&& oflag
& O_CREAT
) {
1462 if (get_compat_mq_attr(&attr
, u_attr
))
1465 return do_mq_open(u_name
, oflag
, mode
, p
);
1468 COMPAT_SYSCALL_DEFINE2(mq_notify
, mqd_t
, mqdes
,
1469 const struct compat_sigevent __user
*, u_notification
)
1471 struct sigevent n
, *p
= NULL
;
1472 if (u_notification
) {
1473 if (get_compat_sigevent(&n
, u_notification
))
1475 if (n
.sigev_notify
== SIGEV_THREAD
)
1476 n
.sigev_value
.sival_ptr
= compat_ptr(n
.sigev_value
.sival_int
);
1479 return do_mq_notify(mqdes
, p
);
1482 COMPAT_SYSCALL_DEFINE3(mq_getsetattr
, mqd_t
, mqdes
,
1483 const struct compat_mq_attr __user
*, u_mqstat
,
1484 struct compat_mq_attr __user
*, u_omqstat
)
1487 struct mq_attr mqstat
, omqstat
;
1488 struct mq_attr
*new = NULL
, *old
= NULL
;
1492 if (get_compat_mq_attr(new, u_mqstat
))
1498 ret
= do_mq_getsetattr(mqdes
, new, old
);
1502 if (put_compat_mq_attr(old
, u_omqstat
))
1508 #ifdef CONFIG_COMPAT_32BIT_TIME
1509 static int compat_prepare_timeout(const struct old_timespec32 __user
*p
,
1510 struct timespec64
*ts
)
1512 if (get_old_timespec32(ts
, p
))
1514 if (!timespec64_valid(ts
))
1519 SYSCALL_DEFINE5(mq_timedsend_time32
, mqd_t
, mqdes
,
1520 const char __user
*, u_msg_ptr
,
1521 unsigned int, msg_len
, unsigned int, msg_prio
,
1522 const struct old_timespec32 __user
*, u_abs_timeout
)
1524 struct timespec64 ts
, *p
= NULL
;
1525 if (u_abs_timeout
) {
1526 int res
= compat_prepare_timeout(u_abs_timeout
, &ts
);
1531 return do_mq_timedsend(mqdes
, u_msg_ptr
, msg_len
, msg_prio
, p
);
1534 SYSCALL_DEFINE5(mq_timedreceive_time32
, mqd_t
, mqdes
,
1535 char __user
*, u_msg_ptr
,
1536 unsigned int, msg_len
, unsigned int __user
*, u_msg_prio
,
1537 const struct old_timespec32 __user
*, u_abs_timeout
)
1539 struct timespec64 ts
, *p
= NULL
;
1540 if (u_abs_timeout
) {
1541 int res
= compat_prepare_timeout(u_abs_timeout
, &ts
);
1546 return do_mq_timedreceive(mqdes
, u_msg_ptr
, msg_len
, u_msg_prio
, p
);
1550 static const struct inode_operations mqueue_dir_inode_operations
= {
1551 .lookup
= simple_lookup
,
1552 .create
= mqueue_create
,
1553 .unlink
= mqueue_unlink
,
1556 static const struct file_operations mqueue_file_operations
= {
1557 .flush
= mqueue_flush_file
,
1558 .poll
= mqueue_poll_file
,
1559 .read
= mqueue_read_file
,
1560 .llseek
= default_llseek
,
1563 static const struct super_operations mqueue_super_ops
= {
1564 .alloc_inode
= mqueue_alloc_inode
,
1565 .destroy_inode
= mqueue_destroy_inode
,
1566 .evict_inode
= mqueue_evict_inode
,
1567 .statfs
= simple_statfs
,
1570 static const struct fs_context_operations mqueue_fs_context_ops
= {
1571 .free
= mqueue_fs_context_free
,
1572 .get_tree
= mqueue_get_tree
,
1575 static struct file_system_type mqueue_fs_type
= {
1577 .init_fs_context
= mqueue_init_fs_context
,
1578 .kill_sb
= kill_litter_super
,
1579 .fs_flags
= FS_USERNS_MOUNT
,
1582 int mq_init_ns(struct ipc_namespace
*ns
)
1586 ns
->mq_queues_count
= 0;
1587 ns
->mq_queues_max
= DFLT_QUEUESMAX
;
1588 ns
->mq_msg_max
= DFLT_MSGMAX
;
1589 ns
->mq_msgsize_max
= DFLT_MSGSIZEMAX
;
1590 ns
->mq_msg_default
= DFLT_MSG
;
1591 ns
->mq_msgsize_default
= DFLT_MSGSIZE
;
1593 m
= mq_create_mount(ns
);
1600 void mq_clear_sbinfo(struct ipc_namespace
*ns
)
1602 ns
->mq_mnt
->mnt_sb
->s_fs_info
= NULL
;
1605 void mq_put_mnt(struct ipc_namespace
*ns
)
1607 kern_unmount(ns
->mq_mnt
);
1610 static int __init
init_mqueue_fs(void)
1614 mqueue_inode_cachep
= kmem_cache_create("mqueue_inode_cache",
1615 sizeof(struct mqueue_inode_info
), 0,
1616 SLAB_HWCACHE_ALIGN
|SLAB_ACCOUNT
, init_once
);
1617 if (mqueue_inode_cachep
== NULL
)
1620 /* ignore failures - they are not fatal */
1621 mq_sysctl_table
= mq_register_sysctl_table();
1623 error
= register_filesystem(&mqueue_fs_type
);
1627 spin_lock_init(&mq_lock
);
1629 error
= mq_init_ns(&init_ipc_ns
);
1631 goto out_filesystem
;
1636 unregister_filesystem(&mqueue_fs_type
);
1638 if (mq_sysctl_table
)
1639 unregister_sysctl_table(mq_sysctl_table
);
1640 kmem_cache_destroy(mqueue_inode_cachep
);
1644 device_initcall(init_mqueue_fs
);