2 * NET4: Implementation of BSD Unix domain sockets.
4 * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 * Linus Torvalds : Assorted bug cures.
13 * Niibe Yutaka : async I/O support.
14 * Carsten Paeth : PF_UNIX check, address fixes.
15 * Alan Cox : Limit size of allocated blocks.
16 * Alan Cox : Fixed the stupid socketpair bug.
17 * Alan Cox : BSD compatibility fine tuning.
18 * Alan Cox : Fixed a bug in connect when interrupted.
19 * Alan Cox : Sorted out a proper draft version of
20 * file descriptor passing hacked up from
22 * Marty Leisner : Fixes to fd passing
23 * Nick Nevin : recvmsg bugfix.
24 * Alan Cox : Started proper garbage collector
25 * Heiko EiBfeldt : Missing verify_area check
26 * Alan Cox : Started POSIXisms
27 * Andreas Schwab : Replace inode by dentry for proper
29 * Kirk Petersen : Made this a module
30 * Christoph Rohland : Elegant non-blocking accept/connect algorithm.
32 * Alexey Kuznetosv : Repaired (I hope) bugs introduces
33 * by above two patches.
34 * Andrea Arcangeli : If possible we block in connect(2)
35 * if the max backlog of the listen socket
36 * is been reached. This won't break
37 * old apps and it will avoid huge amount
38 * of socks hashed (this for unix_gc()
39 * performances reasons).
40 * Security fix that limits the max
41 * number of socks to 2*max_files and
42 * the number of skb queueable in the
44 * Artur Skawina : Hash function optimizations
45 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8)
46 * Malcolm Beattie : Set peercred for socketpair
47 * Michal Ostrowski : Module initialization cleanup.
48 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT,
49 * the core infrastructure is doing that
50 * for all net proto families now (2.5.69+)
53 * Known differences from reference BSD that was tested:
56 * ECONNREFUSED is not returned from one end of a connected() socket to the
57 * other the moment one end closes.
58 * fstat() doesn't return st_dev=0, and give the blksize as high water mark
59 * and a fake inode identifier (nor the BSD first socket fstat twice bug).
61 * accept() returns a path name even if the connecting socket has closed
62 * in the meantime (BSD loses the path and gives up).
63 * accept() returns 0 length path for an unbound connector. BSD returns 16
64 * and a null first byte in the path (but not for gethost/peername - BSD bug ??)
65 * socketpair(...SOCK_RAW..) doesn't panic the kernel.
66 * BSD af_unix apparently has connect forgetting to block properly.
67 * (need to check this with the POSIX spec in detail)
69 * Differences from 2.0.0-11-... (ANK)
70 * Bug fixes and improvements.
71 * - client shutdown killed server socket.
72 * - removed all useless cli/sti pairs.
74 * Semantic changes/extensions.
75 * - generic control message passing.
76 * - SCM_CREDENTIALS control message.
77 * - "Abstract" (not FS based) socket bindings.
78 * Abstract names are sequences of bytes (not zero terminated)
79 * started by 0, so that this name space does not intersect
83 #include <linux/module.h>
84 #include <linux/kernel.h>
85 #include <linux/signal.h>
86 #include <linux/sched.h>
87 #include <linux/errno.h>
88 #include <linux/string.h>
89 #include <linux/stat.h>
90 #include <linux/dcache.h>
91 #include <linux/namei.h>
92 #include <linux/socket.h>
94 #include <linux/fcntl.h>
95 #include <linux/termios.h>
96 #include <linux/sockios.h>
97 #include <linux/net.h>
100 #include <linux/slab.h>
101 #include <asm/uaccess.h>
102 #include <linux/skbuff.h>
103 #include <linux/netdevice.h>
104 #include <net/net_namespace.h>
105 #include <net/sock.h>
106 #include <net/tcp_states.h>
107 #include <net/af_unix.h>
108 #include <linux/proc_fs.h>
109 #include <linux/seq_file.h>
111 #include <linux/init.h>
112 #include <linux/poll.h>
113 #include <linux/rtnetlink.h>
114 #include <linux/mount.h>
115 #include <net/checksum.h>
116 #include <linux/security.h>
118 struct hlist_head unix_socket_table
[UNIX_HASH_SIZE
+ 1];
119 EXPORT_SYMBOL_GPL(unix_socket_table
);
120 DEFINE_SPINLOCK(unix_table_lock
);
121 EXPORT_SYMBOL_GPL(unix_table_lock
);
122 static atomic_long_t unix_nr_socks
;
124 #define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
126 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
128 #ifdef CONFIG_SECURITY_NETWORK
129 static void unix_get_secdata(struct scm_cookie
*scm
, struct sk_buff
*skb
)
131 memcpy(UNIXSID(skb
), &scm
->secid
, sizeof(u32
));
134 static inline void unix_set_secdata(struct scm_cookie
*scm
, struct sk_buff
*skb
)
136 scm
->secid
= *UNIXSID(skb
);
139 static inline void unix_get_secdata(struct scm_cookie
*scm
, struct sk_buff
*skb
)
142 static inline void unix_set_secdata(struct scm_cookie
*scm
, struct sk_buff
*skb
)
144 #endif /* CONFIG_SECURITY_NETWORK */
147 * SMP locking strategy:
148 * hash table is protected with spinlock unix_table_lock
149 * each socket state is protected by separate spin lock.
152 static inline unsigned int unix_hash_fold(__wsum n
)
154 unsigned int hash
= (__force
unsigned int)n
;
158 return hash
&(UNIX_HASH_SIZE
-1);
161 #define unix_peer(sk) (unix_sk(sk)->peer)
163 static inline int unix_our_peer(struct sock
*sk
, struct sock
*osk
)
165 return unix_peer(osk
) == sk
;
168 static inline int unix_may_send(struct sock
*sk
, struct sock
*osk
)
170 return unix_peer(osk
) == NULL
|| unix_our_peer(sk
, osk
);
173 static inline int unix_recvq_full(struct sock
const *sk
)
175 return skb_queue_len(&sk
->sk_receive_queue
) > sk
->sk_max_ack_backlog
;
178 struct sock
*unix_peer_get(struct sock
*s
)
186 unix_state_unlock(s
);
189 EXPORT_SYMBOL_GPL(unix_peer_get
);
191 static inline void unix_release_addr(struct unix_address
*addr
)
193 if (atomic_dec_and_test(&addr
->refcnt
))
198 * Check unix socket name:
199 * - should be not zero length.
200 * - if started by not zero, should be NULL terminated (FS object)
201 * - if started by zero, it is abstract name.
204 static int unix_mkname(struct sockaddr_un
*sunaddr
, int len
, unsigned int *hashp
)
206 if (len
<= sizeof(short) || len
> sizeof(*sunaddr
))
208 if (!sunaddr
|| sunaddr
->sun_family
!= AF_UNIX
)
210 if (sunaddr
->sun_path
[0]) {
212 * This may look like an off by one error but it is a bit more
213 * subtle. 108 is the longest valid AF_UNIX path for a binding.
214 * sun_path[108] doesn't as such exist. However in kernel space
215 * we are guaranteed that it is a valid memory location in our
216 * kernel address buffer.
218 ((char *)sunaddr
)[len
] = 0;
219 len
= strlen(sunaddr
->sun_path
)+1+sizeof(short);
223 *hashp
= unix_hash_fold(csum_partial(sunaddr
, len
, 0));
227 static void __unix_remove_socket(struct sock
*sk
)
229 sk_del_node_init(sk
);
232 static void __unix_insert_socket(struct hlist_head
*list
, struct sock
*sk
)
234 WARN_ON(!sk_unhashed(sk
));
235 sk_add_node(sk
, list
);
238 static inline void unix_remove_socket(struct sock
*sk
)
240 spin_lock(&unix_table_lock
);
241 __unix_remove_socket(sk
);
242 spin_unlock(&unix_table_lock
);
245 static inline void unix_insert_socket(struct hlist_head
*list
, struct sock
*sk
)
247 spin_lock(&unix_table_lock
);
248 __unix_insert_socket(list
, sk
);
249 spin_unlock(&unix_table_lock
);
252 static struct sock
*__unix_find_socket_byname(struct net
*net
,
253 struct sockaddr_un
*sunname
,
254 int len
, int type
, unsigned int hash
)
257 struct hlist_node
*node
;
259 sk_for_each(s
, node
, &unix_socket_table
[hash
^ type
]) {
260 struct unix_sock
*u
= unix_sk(s
);
262 if (!net_eq(sock_net(s
), net
))
265 if (u
->addr
->len
== len
&&
266 !memcmp(u
->addr
->name
, sunname
, len
))
274 static inline struct sock
*unix_find_socket_byname(struct net
*net
,
275 struct sockaddr_un
*sunname
,
281 spin_lock(&unix_table_lock
);
282 s
= __unix_find_socket_byname(net
, sunname
, len
, type
, hash
);
285 spin_unlock(&unix_table_lock
);
289 static struct sock
*unix_find_socket_byinode(struct inode
*i
)
292 struct hlist_node
*node
;
294 spin_lock(&unix_table_lock
);
296 &unix_socket_table
[i
->i_ino
& (UNIX_HASH_SIZE
- 1)]) {
297 struct dentry
*dentry
= unix_sk(s
)->path
.dentry
;
299 if (dentry
&& dentry
->d_inode
== i
) {
306 spin_unlock(&unix_table_lock
);
310 static inline int unix_writable(struct sock
*sk
)
312 return (atomic_read(&sk
->sk_wmem_alloc
) << 2) <= sk
->sk_sndbuf
;
315 static void unix_write_space(struct sock
*sk
)
317 struct socket_wq
*wq
;
320 if (unix_writable(sk
)) {
321 wq
= rcu_dereference(sk
->sk_wq
);
322 if (wq_has_sleeper(wq
))
323 wake_up_interruptible_sync_poll(&wq
->wait
,
324 POLLOUT
| POLLWRNORM
| POLLWRBAND
);
325 sk_wake_async(sk
, SOCK_WAKE_SPACE
, POLL_OUT
);
330 /* When dgram socket disconnects (or changes its peer), we clear its receive
331 * queue of packets arrived from previous peer. First, it allows to do
332 * flow control based only on wmem_alloc; second, sk connected to peer
333 * may receive messages only from that peer. */
334 static void unix_dgram_disconnected(struct sock
*sk
, struct sock
*other
)
336 if (!skb_queue_empty(&sk
->sk_receive_queue
)) {
337 skb_queue_purge(&sk
->sk_receive_queue
);
338 wake_up_interruptible_all(&unix_sk(sk
)->peer_wait
);
340 /* If one link of bidirectional dgram pipe is disconnected,
341 * we signal error. Messages are lost. Do not make this,
342 * when peer was not connected to us.
344 if (!sock_flag(other
, SOCK_DEAD
) && unix_peer(other
) == sk
) {
345 other
->sk_err
= ECONNRESET
;
346 other
->sk_error_report(other
);
351 static void unix_sock_destructor(struct sock
*sk
)
353 struct unix_sock
*u
= unix_sk(sk
);
355 skb_queue_purge(&sk
->sk_receive_queue
);
357 WARN_ON(atomic_read(&sk
->sk_wmem_alloc
));
358 WARN_ON(!sk_unhashed(sk
));
359 WARN_ON(sk
->sk_socket
);
360 if (!sock_flag(sk
, SOCK_DEAD
)) {
361 printk(KERN_INFO
"Attempt to release alive unix socket: %p\n", sk
);
366 unix_release_addr(u
->addr
);
368 atomic_long_dec(&unix_nr_socks
);
370 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, -1);
372 #ifdef UNIX_REFCNT_DEBUG
373 printk(KERN_DEBUG
"UNIX %p is destroyed, %ld are still alive.\n", sk
,
374 atomic_long_read(&unix_nr_socks
));
378 static int unix_release_sock(struct sock
*sk
, int embrion
)
380 struct unix_sock
*u
= unix_sk(sk
);
386 unix_remove_socket(sk
);
391 sk
->sk_shutdown
= SHUTDOWN_MASK
;
393 u
->path
.dentry
= NULL
;
395 state
= sk
->sk_state
;
396 sk
->sk_state
= TCP_CLOSE
;
397 unix_state_unlock(sk
);
399 wake_up_interruptible_all(&u
->peer_wait
);
401 skpair
= unix_peer(sk
);
403 if (skpair
!= NULL
) {
404 if (sk
->sk_type
== SOCK_STREAM
|| sk
->sk_type
== SOCK_SEQPACKET
) {
405 unix_state_lock(skpair
);
407 skpair
->sk_shutdown
= SHUTDOWN_MASK
;
408 if (!skb_queue_empty(&sk
->sk_receive_queue
) || embrion
)
409 skpair
->sk_err
= ECONNRESET
;
410 unix_state_unlock(skpair
);
411 skpair
->sk_state_change(skpair
);
412 sk_wake_async(skpair
, SOCK_WAKE_WAITD
, POLL_HUP
);
414 sock_put(skpair
); /* It may now die */
415 unix_peer(sk
) = NULL
;
418 /* Try to flush out this socket. Throw out buffers at least */
420 while ((skb
= skb_dequeue(&sk
->sk_receive_queue
)) != NULL
) {
421 if (state
== TCP_LISTEN
)
422 unix_release_sock(skb
->sk
, 1);
423 /* passed fds are erased in the kfree_skb hook */
432 /* ---- Socket is dead now and most probably destroyed ---- */
435 * Fixme: BSD difference: In BSD all sockets connected to use get
436 * ECONNRESET and we die on the spot. In Linux we behave
437 * like files and pipes do and wait for the last
440 * Can't we simply set sock->err?
442 * What the above comment does talk about? --ANK(980817)
445 if (unix_tot_inflight
)
446 unix_gc(); /* Garbage collect fds */
451 static void init_peercred(struct sock
*sk
)
453 put_pid(sk
->sk_peer_pid
);
454 if (sk
->sk_peer_cred
)
455 put_cred(sk
->sk_peer_cred
);
456 sk
->sk_peer_pid
= get_pid(task_tgid(current
));
457 sk
->sk_peer_cred
= get_current_cred();
460 static void copy_peercred(struct sock
*sk
, struct sock
*peersk
)
462 put_pid(sk
->sk_peer_pid
);
463 if (sk
->sk_peer_cred
)
464 put_cred(sk
->sk_peer_cred
);
465 sk
->sk_peer_pid
= get_pid(peersk
->sk_peer_pid
);
466 sk
->sk_peer_cred
= get_cred(peersk
->sk_peer_cred
);
469 static int unix_listen(struct socket
*sock
, int backlog
)
472 struct sock
*sk
= sock
->sk
;
473 struct unix_sock
*u
= unix_sk(sk
);
474 struct pid
*old_pid
= NULL
;
475 const struct cred
*old_cred
= NULL
;
478 if (sock
->type
!= SOCK_STREAM
&& sock
->type
!= SOCK_SEQPACKET
)
479 goto out
; /* Only stream/seqpacket sockets accept */
482 goto out
; /* No listens on an unbound socket */
484 if (sk
->sk_state
!= TCP_CLOSE
&& sk
->sk_state
!= TCP_LISTEN
)
486 if (backlog
> sk
->sk_max_ack_backlog
)
487 wake_up_interruptible_all(&u
->peer_wait
);
488 sk
->sk_max_ack_backlog
= backlog
;
489 sk
->sk_state
= TCP_LISTEN
;
490 /* set credentials so connect can copy them */
495 unix_state_unlock(sk
);
503 static int unix_release(struct socket
*);
504 static int unix_bind(struct socket
*, struct sockaddr
*, int);
505 static int unix_stream_connect(struct socket
*, struct sockaddr
*,
506 int addr_len
, int flags
);
507 static int unix_socketpair(struct socket
*, struct socket
*);
508 static int unix_accept(struct socket
*, struct socket
*, int);
509 static int unix_getname(struct socket
*, struct sockaddr
*, int *, int);
510 static unsigned int unix_poll(struct file
*, struct socket
*, poll_table
*);
511 static unsigned int unix_dgram_poll(struct file
*, struct socket
*,
513 static int unix_ioctl(struct socket
*, unsigned int, unsigned long);
514 static int unix_shutdown(struct socket
*, int);
515 static int unix_stream_sendmsg(struct kiocb
*, struct socket
*,
516 struct msghdr
*, size_t);
517 static int unix_stream_recvmsg(struct kiocb
*, struct socket
*,
518 struct msghdr
*, size_t, int);
519 static int unix_dgram_sendmsg(struct kiocb
*, struct socket
*,
520 struct msghdr
*, size_t);
521 static int unix_dgram_recvmsg(struct kiocb
*, struct socket
*,
522 struct msghdr
*, size_t, int);
523 static int unix_dgram_connect(struct socket
*, struct sockaddr
*,
525 static int unix_seqpacket_sendmsg(struct kiocb
*, struct socket
*,
526 struct msghdr
*, size_t);
527 static int unix_seqpacket_recvmsg(struct kiocb
*, struct socket
*,
528 struct msghdr
*, size_t, int);
530 static void unix_set_peek_off(struct sock
*sk
, int val
)
532 struct unix_sock
*u
= unix_sk(sk
);
534 mutex_lock(&u
->readlock
);
535 sk
->sk_peek_off
= val
;
536 mutex_unlock(&u
->readlock
);
540 static const struct proto_ops unix_stream_ops
= {
542 .owner
= THIS_MODULE
,
543 .release
= unix_release
,
545 .connect
= unix_stream_connect
,
546 .socketpair
= unix_socketpair
,
547 .accept
= unix_accept
,
548 .getname
= unix_getname
,
551 .listen
= unix_listen
,
552 .shutdown
= unix_shutdown
,
553 .setsockopt
= sock_no_setsockopt
,
554 .getsockopt
= sock_no_getsockopt
,
555 .sendmsg
= unix_stream_sendmsg
,
556 .recvmsg
= unix_stream_recvmsg
,
557 .mmap
= sock_no_mmap
,
558 .sendpage
= sock_no_sendpage
,
559 .set_peek_off
= unix_set_peek_off
,
562 static const struct proto_ops unix_dgram_ops
= {
564 .owner
= THIS_MODULE
,
565 .release
= unix_release
,
567 .connect
= unix_dgram_connect
,
568 .socketpair
= unix_socketpair
,
569 .accept
= sock_no_accept
,
570 .getname
= unix_getname
,
571 .poll
= unix_dgram_poll
,
573 .listen
= sock_no_listen
,
574 .shutdown
= unix_shutdown
,
575 .setsockopt
= sock_no_setsockopt
,
576 .getsockopt
= sock_no_getsockopt
,
577 .sendmsg
= unix_dgram_sendmsg
,
578 .recvmsg
= unix_dgram_recvmsg
,
579 .mmap
= sock_no_mmap
,
580 .sendpage
= sock_no_sendpage
,
581 .set_peek_off
= unix_set_peek_off
,
584 static const struct proto_ops unix_seqpacket_ops
= {
586 .owner
= THIS_MODULE
,
587 .release
= unix_release
,
589 .connect
= unix_stream_connect
,
590 .socketpair
= unix_socketpair
,
591 .accept
= unix_accept
,
592 .getname
= unix_getname
,
593 .poll
= unix_dgram_poll
,
595 .listen
= unix_listen
,
596 .shutdown
= unix_shutdown
,
597 .setsockopt
= sock_no_setsockopt
,
598 .getsockopt
= sock_no_getsockopt
,
599 .sendmsg
= unix_seqpacket_sendmsg
,
600 .recvmsg
= unix_seqpacket_recvmsg
,
601 .mmap
= sock_no_mmap
,
602 .sendpage
= sock_no_sendpage
,
603 .set_peek_off
= unix_set_peek_off
,
606 static struct proto unix_proto
= {
608 .owner
= THIS_MODULE
,
609 .obj_size
= sizeof(struct unix_sock
),
613 * AF_UNIX sockets do not interact with hardware, hence they
614 * dont trigger interrupts - so it's safe for them to have
615 * bh-unsafe locking for their sk_receive_queue.lock. Split off
616 * this special lock-class by reinitializing the spinlock key:
618 static struct lock_class_key af_unix_sk_receive_queue_lock_key
;
620 static struct sock
*unix_create1(struct net
*net
, struct socket
*sock
)
622 struct sock
*sk
= NULL
;
625 atomic_long_inc(&unix_nr_socks
);
626 if (atomic_long_read(&unix_nr_socks
) > 2 * get_max_files())
629 sk
= sk_alloc(net
, PF_UNIX
, GFP_KERNEL
, &unix_proto
);
633 sock_init_data(sock
, sk
);
634 lockdep_set_class(&sk
->sk_receive_queue
.lock
,
635 &af_unix_sk_receive_queue_lock_key
);
637 sk
->sk_write_space
= unix_write_space
;
638 sk
->sk_max_ack_backlog
= net
->unx
.sysctl_max_dgram_qlen
;
639 sk
->sk_destruct
= unix_sock_destructor
;
641 u
->path
.dentry
= NULL
;
643 spin_lock_init(&u
->lock
);
644 atomic_long_set(&u
->inflight
, 0);
645 INIT_LIST_HEAD(&u
->link
);
646 mutex_init(&u
->readlock
); /* single task reading lock */
647 init_waitqueue_head(&u
->peer_wait
);
648 unix_insert_socket(unix_sockets_unbound
, sk
);
651 atomic_long_dec(&unix_nr_socks
);
654 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, 1);
660 static int unix_create(struct net
*net
, struct socket
*sock
, int protocol
,
663 if (protocol
&& protocol
!= PF_UNIX
)
664 return -EPROTONOSUPPORT
;
666 sock
->state
= SS_UNCONNECTED
;
668 switch (sock
->type
) {
670 sock
->ops
= &unix_stream_ops
;
673 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
677 sock
->type
= SOCK_DGRAM
;
679 sock
->ops
= &unix_dgram_ops
;
682 sock
->ops
= &unix_seqpacket_ops
;
685 return -ESOCKTNOSUPPORT
;
688 return unix_create1(net
, sock
) ? 0 : -ENOMEM
;
691 static int unix_release(struct socket
*sock
)
693 struct sock
*sk
= sock
->sk
;
700 return unix_release_sock(sk
, 0);
703 static int unix_autobind(struct socket
*sock
)
705 struct sock
*sk
= sock
->sk
;
706 struct net
*net
= sock_net(sk
);
707 struct unix_sock
*u
= unix_sk(sk
);
708 static u32 ordernum
= 1;
709 struct unix_address
*addr
;
711 unsigned int retries
= 0;
713 mutex_lock(&u
->readlock
);
720 addr
= kzalloc(sizeof(*addr
) + sizeof(short) + 16, GFP_KERNEL
);
724 addr
->name
->sun_family
= AF_UNIX
;
725 atomic_set(&addr
->refcnt
, 1);
728 addr
->len
= sprintf(addr
->name
->sun_path
+1, "%05x", ordernum
) + 1 + sizeof(short);
729 addr
->hash
= unix_hash_fold(csum_partial(addr
->name
, addr
->len
, 0));
731 spin_lock(&unix_table_lock
);
732 ordernum
= (ordernum
+1)&0xFFFFF;
734 if (__unix_find_socket_byname(net
, addr
->name
, addr
->len
, sock
->type
,
736 spin_unlock(&unix_table_lock
);
738 * __unix_find_socket_byname() may take long time if many names
739 * are already in use.
742 /* Give up if all names seems to be in use. */
743 if (retries
++ == 0xFFFFF) {
750 addr
->hash
^= sk
->sk_type
;
752 __unix_remove_socket(sk
);
754 __unix_insert_socket(&unix_socket_table
[addr
->hash
], sk
);
755 spin_unlock(&unix_table_lock
);
758 out
: mutex_unlock(&u
->readlock
);
762 static struct sock
*unix_find_other(struct net
*net
,
763 struct sockaddr_un
*sunname
, int len
,
764 int type
, unsigned int hash
, int *error
)
770 if (sunname
->sun_path
[0]) {
772 err
= kern_path(sunname
->sun_path
, LOOKUP_FOLLOW
, &path
);
775 inode
= path
.dentry
->d_inode
;
776 err
= inode_permission(inode
, MAY_WRITE
);
781 if (!S_ISSOCK(inode
->i_mode
))
783 u
= unix_find_socket_byinode(inode
);
787 if (u
->sk_type
== type
)
793 if (u
->sk_type
!= type
) {
799 u
= unix_find_socket_byname(net
, sunname
, len
, type
, hash
);
801 struct dentry
*dentry
;
802 dentry
= unix_sk(u
)->path
.dentry
;
804 touch_atime(&unix_sk(u
)->path
);
818 static int unix_bind(struct socket
*sock
, struct sockaddr
*uaddr
, int addr_len
)
820 struct sock
*sk
= sock
->sk
;
821 struct net
*net
= sock_net(sk
);
822 struct unix_sock
*u
= unix_sk(sk
);
823 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)uaddr
;
824 char *sun_path
= sunaddr
->sun_path
;
825 struct dentry
*dentry
= NULL
;
829 struct unix_address
*addr
;
830 struct hlist_head
*list
;
833 if (sunaddr
->sun_family
!= AF_UNIX
)
836 if (addr_len
== sizeof(short)) {
837 err
= unix_autobind(sock
);
841 err
= unix_mkname(sunaddr
, addr_len
, &hash
);
846 mutex_lock(&u
->readlock
);
853 addr
= kmalloc(sizeof(*addr
)+addr_len
, GFP_KERNEL
);
857 memcpy(addr
->name
, sunaddr
, addr_len
);
858 addr
->len
= addr_len
;
859 addr
->hash
= hash
^ sk
->sk_type
;
860 atomic_set(&addr
->refcnt
, 1);
866 * Get the parent directory, calculate the hash for last
869 dentry
= kern_path_create(AT_FDCWD
, sun_path
, &path
, 0);
870 err
= PTR_ERR(dentry
);
872 goto out_mknod_parent
;
875 * All right, let's create it.
878 (SOCK_INODE(sock
)->i_mode
& ~current_umask());
879 err
= mnt_want_write(path
.mnt
);
882 err
= security_path_mknod(&path
, dentry
, mode
, 0);
884 goto out_mknod_drop_write
;
885 err
= vfs_mknod(path
.dentry
->d_inode
, dentry
, mode
, 0);
886 out_mknod_drop_write
:
887 mnt_drop_write(path
.mnt
);
892 done_path_create(&path
, dentry
);
893 path
.dentry
= dentry
;
895 addr
->hash
= UNIX_HASH_SIZE
;
898 spin_lock(&unix_table_lock
);
902 if (__unix_find_socket_byname(net
, sunaddr
, addr_len
,
903 sk
->sk_type
, hash
)) {
904 unix_release_addr(addr
);
908 list
= &unix_socket_table
[addr
->hash
];
910 list
= &unix_socket_table
[dentry
->d_inode
->i_ino
& (UNIX_HASH_SIZE
-1)];
915 __unix_remove_socket(sk
);
917 __unix_insert_socket(list
, sk
);
920 spin_unlock(&unix_table_lock
);
922 mutex_unlock(&u
->readlock
);
927 done_path_create(&path
, dentry
);
931 unix_release_addr(addr
);
935 static void unix_state_double_lock(struct sock
*sk1
, struct sock
*sk2
)
937 if (unlikely(sk1
== sk2
) || !sk2
) {
938 unix_state_lock(sk1
);
942 unix_state_lock(sk1
);
943 unix_state_lock_nested(sk2
);
945 unix_state_lock(sk2
);
946 unix_state_lock_nested(sk1
);
950 static void unix_state_double_unlock(struct sock
*sk1
, struct sock
*sk2
)
952 if (unlikely(sk1
== sk2
) || !sk2
) {
953 unix_state_unlock(sk1
);
956 unix_state_unlock(sk1
);
957 unix_state_unlock(sk2
);
960 static int unix_dgram_connect(struct socket
*sock
, struct sockaddr
*addr
,
963 struct sock
*sk
= sock
->sk
;
964 struct net
*net
= sock_net(sk
);
965 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)addr
;
970 if (addr
->sa_family
!= AF_UNSPEC
) {
971 err
= unix_mkname(sunaddr
, alen
, &hash
);
976 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) &&
977 !unix_sk(sk
)->addr
&& (err
= unix_autobind(sock
)) != 0)
981 other
= unix_find_other(net
, sunaddr
, alen
, sock
->type
, hash
, &err
);
985 unix_state_double_lock(sk
, other
);
987 /* Apparently VFS overslept socket death. Retry. */
988 if (sock_flag(other
, SOCK_DEAD
)) {
989 unix_state_double_unlock(sk
, other
);
995 if (!unix_may_send(sk
, other
))
998 err
= security_unix_may_send(sk
->sk_socket
, other
->sk_socket
);
1004 * 1003.1g breaking connected state with AF_UNSPEC
1007 unix_state_double_lock(sk
, other
);
1011 * If it was connected, reconnect.
1013 if (unix_peer(sk
)) {
1014 struct sock
*old_peer
= unix_peer(sk
);
1015 unix_peer(sk
) = other
;
1016 unix_state_double_unlock(sk
, other
);
1018 if (other
!= old_peer
)
1019 unix_dgram_disconnected(sk
, old_peer
);
1022 unix_peer(sk
) = other
;
1023 unix_state_double_unlock(sk
, other
);
1028 unix_state_double_unlock(sk
, other
);
1034 static long unix_wait_for_peer(struct sock
*other
, long timeo
)
1036 struct unix_sock
*u
= unix_sk(other
);
1040 prepare_to_wait_exclusive(&u
->peer_wait
, &wait
, TASK_INTERRUPTIBLE
);
1042 sched
= !sock_flag(other
, SOCK_DEAD
) &&
1043 !(other
->sk_shutdown
& RCV_SHUTDOWN
) &&
1044 unix_recvq_full(other
);
1046 unix_state_unlock(other
);
1049 timeo
= schedule_timeout(timeo
);
1051 finish_wait(&u
->peer_wait
, &wait
);
1055 static int unix_stream_connect(struct socket
*sock
, struct sockaddr
*uaddr
,
1056 int addr_len
, int flags
)
1058 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)uaddr
;
1059 struct sock
*sk
= sock
->sk
;
1060 struct net
*net
= sock_net(sk
);
1061 struct unix_sock
*u
= unix_sk(sk
), *newu
, *otheru
;
1062 struct sock
*newsk
= NULL
;
1063 struct sock
*other
= NULL
;
1064 struct sk_buff
*skb
= NULL
;
1070 err
= unix_mkname(sunaddr
, addr_len
, &hash
);
1075 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) && !u
->addr
&&
1076 (err
= unix_autobind(sock
)) != 0)
1079 timeo
= sock_sndtimeo(sk
, flags
& O_NONBLOCK
);
1081 /* First of all allocate resources.
1082 If we will make it after state is locked,
1083 we will have to recheck all again in any case.
1088 /* create new sock for complete connection */
1089 newsk
= unix_create1(sock_net(sk
), NULL
);
1093 /* Allocate skb for sending to listening sock */
1094 skb
= sock_wmalloc(newsk
, 1, 0, GFP_KERNEL
);
1099 /* Find listening sock. */
1100 other
= unix_find_other(net
, sunaddr
, addr_len
, sk
->sk_type
, hash
, &err
);
1104 /* Latch state of peer */
1105 unix_state_lock(other
);
1107 /* Apparently VFS overslept socket death. Retry. */
1108 if (sock_flag(other
, SOCK_DEAD
)) {
1109 unix_state_unlock(other
);
1114 err
= -ECONNREFUSED
;
1115 if (other
->sk_state
!= TCP_LISTEN
)
1117 if (other
->sk_shutdown
& RCV_SHUTDOWN
)
1120 if (unix_recvq_full(other
)) {
1125 timeo
= unix_wait_for_peer(other
, timeo
);
1127 err
= sock_intr_errno(timeo
);
1128 if (signal_pending(current
))
1136 It is tricky place. We need to grab our state lock and cannot
1137 drop lock on peer. It is dangerous because deadlock is
1138 possible. Connect to self case and simultaneous
1139 attempt to connect are eliminated by checking socket
1140 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1141 check this before attempt to grab lock.
1143 Well, and we have to recheck the state after socket locked.
1149 /* This is ok... continue with connect */
1151 case TCP_ESTABLISHED
:
1152 /* Socket is already connected */
1160 unix_state_lock_nested(sk
);
1162 if (sk
->sk_state
!= st
) {
1163 unix_state_unlock(sk
);
1164 unix_state_unlock(other
);
1169 err
= security_unix_stream_connect(sk
, other
, newsk
);
1171 unix_state_unlock(sk
);
1175 /* The way is open! Fastly set all the necessary fields... */
1178 unix_peer(newsk
) = sk
;
1179 newsk
->sk_state
= TCP_ESTABLISHED
;
1180 newsk
->sk_type
= sk
->sk_type
;
1181 init_peercred(newsk
);
1182 newu
= unix_sk(newsk
);
1183 RCU_INIT_POINTER(newsk
->sk_wq
, &newu
->peer_wq
);
1184 otheru
= unix_sk(other
);
1186 /* copy address information from listening to new sock*/
1188 atomic_inc(&otheru
->addr
->refcnt
);
1189 newu
->addr
= otheru
->addr
;
1191 if (otheru
->path
.dentry
) {
1192 path_get(&otheru
->path
);
1193 newu
->path
= otheru
->path
;
1196 /* Set credentials */
1197 copy_peercred(sk
, other
);
1199 sock
->state
= SS_CONNECTED
;
1200 sk
->sk_state
= TCP_ESTABLISHED
;
1203 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1204 unix_peer(sk
) = newsk
;
1206 unix_state_unlock(sk
);
1208 /* take ten and and send info to listening sock */
1209 spin_lock(&other
->sk_receive_queue
.lock
);
1210 __skb_queue_tail(&other
->sk_receive_queue
, skb
);
1211 spin_unlock(&other
->sk_receive_queue
.lock
);
1212 unix_state_unlock(other
);
1213 other
->sk_data_ready(other
, 0);
1219 unix_state_unlock(other
);
1224 unix_release_sock(newsk
, 0);
1230 static int unix_socketpair(struct socket
*socka
, struct socket
*sockb
)
1232 struct sock
*ska
= socka
->sk
, *skb
= sockb
->sk
;
1234 /* Join our sockets back to back */
1237 unix_peer(ska
) = skb
;
1238 unix_peer(skb
) = ska
;
1242 if (ska
->sk_type
!= SOCK_DGRAM
) {
1243 ska
->sk_state
= TCP_ESTABLISHED
;
1244 skb
->sk_state
= TCP_ESTABLISHED
;
1245 socka
->state
= SS_CONNECTED
;
1246 sockb
->state
= SS_CONNECTED
;
1251 static int unix_accept(struct socket
*sock
, struct socket
*newsock
, int flags
)
1253 struct sock
*sk
= sock
->sk
;
1255 struct sk_buff
*skb
;
1259 if (sock
->type
!= SOCK_STREAM
&& sock
->type
!= SOCK_SEQPACKET
)
1263 if (sk
->sk_state
!= TCP_LISTEN
)
1266 /* If socket state is TCP_LISTEN it cannot change (for now...),
1267 * so that no locks are necessary.
1270 skb
= skb_recv_datagram(sk
, 0, flags
&O_NONBLOCK
, &err
);
1272 /* This means receive shutdown. */
1279 skb_free_datagram(sk
, skb
);
1280 wake_up_interruptible(&unix_sk(sk
)->peer_wait
);
1282 /* attach accepted sock to socket */
1283 unix_state_lock(tsk
);
1284 newsock
->state
= SS_CONNECTED
;
1285 sock_graft(tsk
, newsock
);
1286 unix_state_unlock(tsk
);
1294 static int unix_getname(struct socket
*sock
, struct sockaddr
*uaddr
, int *uaddr_len
, int peer
)
1296 struct sock
*sk
= sock
->sk
;
1297 struct unix_sock
*u
;
1298 DECLARE_SOCKADDR(struct sockaddr_un
*, sunaddr
, uaddr
);
1302 sk
= unix_peer_get(sk
);
1313 unix_state_lock(sk
);
1315 sunaddr
->sun_family
= AF_UNIX
;
1316 sunaddr
->sun_path
[0] = 0;
1317 *uaddr_len
= sizeof(short);
1319 struct unix_address
*addr
= u
->addr
;
1321 *uaddr_len
= addr
->len
;
1322 memcpy(sunaddr
, addr
->name
, *uaddr_len
);
1324 unix_state_unlock(sk
);
1330 static void unix_detach_fds(struct scm_cookie
*scm
, struct sk_buff
*skb
)
1334 scm
->fp
= UNIXCB(skb
).fp
;
1335 UNIXCB(skb
).fp
= NULL
;
1337 for (i
= scm
->fp
->count
-1; i
>= 0; i
--)
1338 unix_notinflight(scm
->fp
->fp
[i
]);
1341 static void unix_destruct_scm(struct sk_buff
*skb
)
1343 struct scm_cookie scm
;
1344 memset(&scm
, 0, sizeof(scm
));
1345 scm
.pid
= UNIXCB(skb
).pid
;
1346 scm
.cred
= UNIXCB(skb
).cred
;
1348 unix_detach_fds(&scm
, skb
);
1350 /* Alas, it calls VFS */
1351 /* So fscking what? fput() had been SMP-safe since the last Summer */
1356 #define MAX_RECURSION_LEVEL 4
1358 static int unix_attach_fds(struct scm_cookie
*scm
, struct sk_buff
*skb
)
1361 unsigned char max_level
= 0;
1362 int unix_sock_count
= 0;
1364 for (i
= scm
->fp
->count
- 1; i
>= 0; i
--) {
1365 struct sock
*sk
= unix_get_socket(scm
->fp
->fp
[i
]);
1369 max_level
= max(max_level
,
1370 unix_sk(sk
)->recursion_level
);
1373 if (unlikely(max_level
> MAX_RECURSION_LEVEL
))
1374 return -ETOOMANYREFS
;
1377 * Need to duplicate file references for the sake of garbage
1378 * collection. Otherwise a socket in the fps might become a
1379 * candidate for GC while the skb is not yet queued.
1381 UNIXCB(skb
).fp
= scm_fp_dup(scm
->fp
);
1382 if (!UNIXCB(skb
).fp
)
1385 if (unix_sock_count
) {
1386 for (i
= scm
->fp
->count
- 1; i
>= 0; i
--)
1387 unix_inflight(scm
->fp
->fp
[i
]);
1392 static int unix_scm_to_skb(struct scm_cookie
*scm
, struct sk_buff
*skb
, bool send_fds
)
1396 UNIXCB(skb
).pid
= get_pid(scm
->pid
);
1398 UNIXCB(skb
).cred
= get_cred(scm
->cred
);
1399 UNIXCB(skb
).fp
= NULL
;
1400 if (scm
->fp
&& send_fds
)
1401 err
= unix_attach_fds(scm
, skb
);
1403 skb
->destructor
= unix_destruct_scm
;
1408 * Some apps rely on write() giving SCM_CREDENTIALS
1409 * We include credentials if source or destination socket
1410 * asserted SOCK_PASSCRED.
1412 static void maybe_add_creds(struct sk_buff
*skb
, const struct socket
*sock
,
1413 const struct sock
*other
)
1415 if (UNIXCB(skb
).cred
)
1417 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) ||
1418 !other
->sk_socket
||
1419 test_bit(SOCK_PASSCRED
, &other
->sk_socket
->flags
)) {
1420 UNIXCB(skb
).pid
= get_pid(task_tgid(current
));
1421 UNIXCB(skb
).cred
= get_current_cred();
1426 * Send AF_UNIX data.
1429 static int unix_dgram_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1430 struct msghdr
*msg
, size_t len
)
1432 struct sock_iocb
*siocb
= kiocb_to_siocb(kiocb
);
1433 struct sock
*sk
= sock
->sk
;
1434 struct net
*net
= sock_net(sk
);
1435 struct unix_sock
*u
= unix_sk(sk
);
1436 struct sockaddr_un
*sunaddr
= msg
->msg_name
;
1437 struct sock
*other
= NULL
;
1438 int namelen
= 0; /* fake GCC */
1441 struct sk_buff
*skb
;
1443 struct scm_cookie tmp_scm
;
1447 if (NULL
== siocb
->scm
)
1448 siocb
->scm
= &tmp_scm
;
1450 err
= scm_send(sock
, msg
, siocb
->scm
);
1455 if (msg
->msg_flags
&MSG_OOB
)
1458 if (msg
->msg_namelen
) {
1459 err
= unix_mkname(sunaddr
, msg
->msg_namelen
, &hash
);
1466 other
= unix_peer_get(sk
);
1471 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) && !u
->addr
1472 && (err
= unix_autobind(sock
)) != 0)
1476 if (len
> sk
->sk_sndbuf
- 32)
1479 if (len
> SKB_MAX_ALLOC
)
1480 data_len
= min_t(size_t,
1481 len
- SKB_MAX_ALLOC
,
1482 MAX_SKB_FRAGS
* PAGE_SIZE
);
1484 skb
= sock_alloc_send_pskb(sk
, len
- data_len
, data_len
,
1485 msg
->msg_flags
& MSG_DONTWAIT
, &err
);
1489 err
= unix_scm_to_skb(siocb
->scm
, skb
, true);
1492 max_level
= err
+ 1;
1493 unix_get_secdata(siocb
->scm
, skb
);
1495 skb_put(skb
, len
- data_len
);
1496 skb
->data_len
= data_len
;
1498 err
= skb_copy_datagram_from_iovec(skb
, 0, msg
->msg_iov
, 0, len
);
1502 timeo
= sock_sndtimeo(sk
, msg
->msg_flags
& MSG_DONTWAIT
);
1507 if (sunaddr
== NULL
)
1510 other
= unix_find_other(net
, sunaddr
, namelen
, sk
->sk_type
,
1516 if (sk_filter(other
, skb
) < 0) {
1517 /* Toss the packet but do not return any error to the sender */
1522 unix_state_lock(other
);
1524 if (!unix_may_send(sk
, other
))
1527 if (sock_flag(other
, SOCK_DEAD
)) {
1529 * Check with 1003.1g - what should
1532 unix_state_unlock(other
);
1536 unix_state_lock(sk
);
1537 if (unix_peer(sk
) == other
) {
1538 unix_peer(sk
) = NULL
;
1539 unix_state_unlock(sk
);
1541 unix_dgram_disconnected(sk
, other
);
1543 err
= -ECONNREFUSED
;
1545 unix_state_unlock(sk
);
1555 if (other
->sk_shutdown
& RCV_SHUTDOWN
)
1558 if (sk
->sk_type
!= SOCK_SEQPACKET
) {
1559 err
= security_unix_may_send(sk
->sk_socket
, other
->sk_socket
);
1564 if (unix_peer(other
) != sk
&& unix_recvq_full(other
)) {
1570 timeo
= unix_wait_for_peer(other
, timeo
);
1572 err
= sock_intr_errno(timeo
);
1573 if (signal_pending(current
))
1579 if (sock_flag(other
, SOCK_RCVTSTAMP
))
1580 __net_timestamp(skb
);
1581 maybe_add_creds(skb
, sock
, other
);
1582 skb_queue_tail(&other
->sk_receive_queue
, skb
);
1583 if (max_level
> unix_sk(other
)->recursion_level
)
1584 unix_sk(other
)->recursion_level
= max_level
;
1585 unix_state_unlock(other
);
1586 other
->sk_data_ready(other
, len
);
1588 scm_destroy(siocb
->scm
);
1592 unix_state_unlock(other
);
1598 scm_destroy(siocb
->scm
);
1603 static int unix_stream_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1604 struct msghdr
*msg
, size_t len
)
1606 struct sock_iocb
*siocb
= kiocb_to_siocb(kiocb
);
1607 struct sock
*sk
= sock
->sk
;
1608 struct sock
*other
= NULL
;
1610 struct sk_buff
*skb
;
1612 struct scm_cookie tmp_scm
;
1613 bool fds_sent
= false;
1616 if (NULL
== siocb
->scm
)
1617 siocb
->scm
= &tmp_scm
;
1619 err
= scm_send(sock
, msg
, siocb
->scm
);
1624 if (msg
->msg_flags
&MSG_OOB
)
1627 if (msg
->msg_namelen
) {
1628 err
= sk
->sk_state
== TCP_ESTABLISHED
? -EISCONN
: -EOPNOTSUPP
;
1632 other
= unix_peer(sk
);
1637 if (sk
->sk_shutdown
& SEND_SHUTDOWN
)
1640 while (sent
< len
) {
1642 * Optimisation for the fact that under 0.01% of X
1643 * messages typically need breaking up.
1648 /* Keep two messages in the pipe so it schedules better */
1649 if (size
> ((sk
->sk_sndbuf
>> 1) - 64))
1650 size
= (sk
->sk_sndbuf
>> 1) - 64;
1652 if (size
> SKB_MAX_ALLOC
)
1653 size
= SKB_MAX_ALLOC
;
1659 skb
= sock_alloc_send_skb(sk
, size
, msg
->msg_flags
&MSG_DONTWAIT
,
1666 * If you pass two values to the sock_alloc_send_skb
1667 * it tries to grab the large buffer with GFP_NOFS
1668 * (which can fail easily), and if it fails grab the
1669 * fallback size buffer which is under a page and will
1672 size
= min_t(int, size
, skb_tailroom(skb
));
1675 /* Only send the fds in the first buffer */
1676 err
= unix_scm_to_skb(siocb
->scm
, skb
, !fds_sent
);
1681 max_level
= err
+ 1;
1684 err
= memcpy_fromiovec(skb_put(skb
, size
), msg
->msg_iov
, size
);
1690 unix_state_lock(other
);
1692 if (sock_flag(other
, SOCK_DEAD
) ||
1693 (other
->sk_shutdown
& RCV_SHUTDOWN
))
1696 maybe_add_creds(skb
, sock
, other
);
1697 skb_queue_tail(&other
->sk_receive_queue
, skb
);
1698 if (max_level
> unix_sk(other
)->recursion_level
)
1699 unix_sk(other
)->recursion_level
= max_level
;
1700 unix_state_unlock(other
);
1701 other
->sk_data_ready(other
, size
);
1705 scm_destroy(siocb
->scm
);
1711 unix_state_unlock(other
);
1714 if (sent
== 0 && !(msg
->msg_flags
&MSG_NOSIGNAL
))
1715 send_sig(SIGPIPE
, current
, 0);
1718 scm_destroy(siocb
->scm
);
1720 return sent
? : err
;
1723 static int unix_seqpacket_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1724 struct msghdr
*msg
, size_t len
)
1727 struct sock
*sk
= sock
->sk
;
1729 err
= sock_error(sk
);
1733 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1736 if (msg
->msg_namelen
)
1737 msg
->msg_namelen
= 0;
1739 return unix_dgram_sendmsg(kiocb
, sock
, msg
, len
);
1742 static int unix_seqpacket_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1743 struct msghdr
*msg
, size_t size
,
1746 struct sock
*sk
= sock
->sk
;
1748 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1751 return unix_dgram_recvmsg(iocb
, sock
, msg
, size
, flags
);
1754 static void unix_copy_addr(struct msghdr
*msg
, struct sock
*sk
)
1756 struct unix_sock
*u
= unix_sk(sk
);
1758 msg
->msg_namelen
= 0;
1760 msg
->msg_namelen
= u
->addr
->len
;
1761 memcpy(msg
->msg_name
, u
->addr
->name
, u
->addr
->len
);
1765 static int unix_dgram_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1766 struct msghdr
*msg
, size_t size
,
1769 struct sock_iocb
*siocb
= kiocb_to_siocb(iocb
);
1770 struct scm_cookie tmp_scm
;
1771 struct sock
*sk
= sock
->sk
;
1772 struct unix_sock
*u
= unix_sk(sk
);
1773 int noblock
= flags
& MSG_DONTWAIT
;
1774 struct sk_buff
*skb
;
1782 msg
->msg_namelen
= 0;
1784 err
= mutex_lock_interruptible(&u
->readlock
);
1786 err
= sock_intr_errno(sock_rcvtimeo(sk
, noblock
));
1790 skip
= sk_peek_offset(sk
, flags
);
1792 skb
= __skb_recv_datagram(sk
, flags
, &peeked
, &skip
, &err
);
1794 unix_state_lock(sk
);
1795 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1796 if (sk
->sk_type
== SOCK_SEQPACKET
&& err
== -EAGAIN
&&
1797 (sk
->sk_shutdown
& RCV_SHUTDOWN
))
1799 unix_state_unlock(sk
);
1803 wake_up_interruptible_sync_poll(&u
->peer_wait
,
1804 POLLOUT
| POLLWRNORM
| POLLWRBAND
);
1807 unix_copy_addr(msg
, skb
->sk
);
1809 if (size
> skb
->len
- skip
)
1810 size
= skb
->len
- skip
;
1811 else if (size
< skb
->len
- skip
)
1812 msg
->msg_flags
|= MSG_TRUNC
;
1814 err
= skb_copy_datagram_iovec(skb
, skip
, msg
->msg_iov
, size
);
1818 if (sock_flag(sk
, SOCK_RCVTSTAMP
))
1819 __sock_recv_timestamp(msg
, sk
, skb
);
1822 siocb
->scm
= &tmp_scm
;
1823 memset(&tmp_scm
, 0, sizeof(tmp_scm
));
1825 scm_set_cred(siocb
->scm
, UNIXCB(skb
).pid
, UNIXCB(skb
).cred
);
1826 unix_set_secdata(siocb
->scm
, skb
);
1828 if (!(flags
& MSG_PEEK
)) {
1830 unix_detach_fds(siocb
->scm
, skb
);
1832 sk_peek_offset_bwd(sk
, skb
->len
);
1834 /* It is questionable: on PEEK we could:
1835 - do not return fds - good, but too simple 8)
1836 - return fds, and do not return them on read (old strategy,
1838 - clone fds (I chose it for now, it is the most universal
1841 POSIX 1003.1g does not actually define this clearly
1842 at all. POSIX 1003.1g doesn't define a lot of things
1847 sk_peek_offset_fwd(sk
, size
);
1850 siocb
->scm
->fp
= scm_fp_dup(UNIXCB(skb
).fp
);
1852 err
= (flags
& MSG_TRUNC
) ? skb
->len
- skip
: size
;
1854 scm_recv(sock
, msg
, siocb
->scm
, flags
);
1857 skb_free_datagram(sk
, skb
);
1859 mutex_unlock(&u
->readlock
);
1865 * Sleep until data has arrive. But check for races..
1868 static long unix_stream_data_wait(struct sock
*sk
, long timeo
)
1872 unix_state_lock(sk
);
1875 prepare_to_wait(sk_sleep(sk
), &wait
, TASK_INTERRUPTIBLE
);
1877 if (!skb_queue_empty(&sk
->sk_receive_queue
) ||
1879 (sk
->sk_shutdown
& RCV_SHUTDOWN
) ||
1880 signal_pending(current
) ||
1884 set_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
1885 unix_state_unlock(sk
);
1886 timeo
= schedule_timeout(timeo
);
1887 unix_state_lock(sk
);
1888 clear_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
1891 finish_wait(sk_sleep(sk
), &wait
);
1892 unix_state_unlock(sk
);
1898 static int unix_stream_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1899 struct msghdr
*msg
, size_t size
,
1902 struct sock_iocb
*siocb
= kiocb_to_siocb(iocb
);
1903 struct scm_cookie tmp_scm
;
1904 struct sock
*sk
= sock
->sk
;
1905 struct unix_sock
*u
= unix_sk(sk
);
1906 struct sockaddr_un
*sunaddr
= msg
->msg_name
;
1908 int check_creds
= 0;
1915 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1922 target
= sock_rcvlowat(sk
, flags
&MSG_WAITALL
, size
);
1923 timeo
= sock_rcvtimeo(sk
, flags
&MSG_DONTWAIT
);
1925 msg
->msg_namelen
= 0;
1927 /* Lock the socket to prevent queue disordering
1928 * while sleeps in memcpy_tomsg
1932 siocb
->scm
= &tmp_scm
;
1933 memset(&tmp_scm
, 0, sizeof(tmp_scm
));
1936 err
= mutex_lock_interruptible(&u
->readlock
);
1938 err
= sock_intr_errno(timeo
);
1942 skip
= sk_peek_offset(sk
, flags
);
1946 struct sk_buff
*skb
;
1948 unix_state_lock(sk
);
1949 skb
= skb_peek(&sk
->sk_receive_queue
);
1952 unix_sk(sk
)->recursion_level
= 0;
1953 if (copied
>= target
)
1957 * POSIX 1003.1g mandates this order.
1960 err
= sock_error(sk
);
1963 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
1966 unix_state_unlock(sk
);
1970 mutex_unlock(&u
->readlock
);
1972 timeo
= unix_stream_data_wait(sk
, timeo
);
1974 if (signal_pending(current
)
1975 || mutex_lock_interruptible(&u
->readlock
)) {
1976 err
= sock_intr_errno(timeo
);
1982 unix_state_unlock(sk
);
1986 if (skip
>= skb
->len
) {
1988 skb
= skb_peek_next(skb
, &sk
->sk_receive_queue
);
1992 unix_state_unlock(sk
);
1995 /* Never glue messages from different writers */
1996 if ((UNIXCB(skb
).pid
!= siocb
->scm
->pid
) ||
1997 (UNIXCB(skb
).cred
!= siocb
->scm
->cred
))
2000 /* Copy credentials */
2001 scm_set_cred(siocb
->scm
, UNIXCB(skb
).pid
, UNIXCB(skb
).cred
);
2005 /* Copy address just once */
2007 unix_copy_addr(msg
, skb
->sk
);
2011 chunk
= min_t(unsigned int, skb
->len
- skip
, size
);
2012 if (memcpy_toiovec(msg
->msg_iov
, skb
->data
+ skip
, chunk
)) {
2020 /* Mark read part of skb as used */
2021 if (!(flags
& MSG_PEEK
)) {
2022 skb_pull(skb
, chunk
);
2024 sk_peek_offset_bwd(sk
, chunk
);
2027 unix_detach_fds(siocb
->scm
, skb
);
2032 skb_unlink(skb
, &sk
->sk_receive_queue
);
2038 /* It is questionable, see note in unix_dgram_recvmsg.
2041 siocb
->scm
->fp
= scm_fp_dup(UNIXCB(skb
).fp
);
2043 sk_peek_offset_fwd(sk
, chunk
);
2049 mutex_unlock(&u
->readlock
);
2050 scm_recv(sock
, msg
, siocb
->scm
, flags
);
2052 return copied
? : err
;
2055 static int unix_shutdown(struct socket
*sock
, int mode
)
2057 struct sock
*sk
= sock
->sk
;
2060 mode
= (mode
+1)&(RCV_SHUTDOWN
|SEND_SHUTDOWN
);
2065 unix_state_lock(sk
);
2066 sk
->sk_shutdown
|= mode
;
2067 other
= unix_peer(sk
);
2070 unix_state_unlock(sk
);
2071 sk
->sk_state_change(sk
);
2074 (sk
->sk_type
== SOCK_STREAM
|| sk
->sk_type
== SOCK_SEQPACKET
)) {
2078 if (mode
&RCV_SHUTDOWN
)
2079 peer_mode
|= SEND_SHUTDOWN
;
2080 if (mode
&SEND_SHUTDOWN
)
2081 peer_mode
|= RCV_SHUTDOWN
;
2082 unix_state_lock(other
);
2083 other
->sk_shutdown
|= peer_mode
;
2084 unix_state_unlock(other
);
2085 other
->sk_state_change(other
);
2086 if (peer_mode
== SHUTDOWN_MASK
)
2087 sk_wake_async(other
, SOCK_WAKE_WAITD
, POLL_HUP
);
2088 else if (peer_mode
& RCV_SHUTDOWN
)
2089 sk_wake_async(other
, SOCK_WAKE_WAITD
, POLL_IN
);
2097 long unix_inq_len(struct sock
*sk
)
2099 struct sk_buff
*skb
;
2102 if (sk
->sk_state
== TCP_LISTEN
)
2105 spin_lock(&sk
->sk_receive_queue
.lock
);
2106 if (sk
->sk_type
== SOCK_STREAM
||
2107 sk
->sk_type
== SOCK_SEQPACKET
) {
2108 skb_queue_walk(&sk
->sk_receive_queue
, skb
)
2111 skb
= skb_peek(&sk
->sk_receive_queue
);
2115 spin_unlock(&sk
->sk_receive_queue
.lock
);
2119 EXPORT_SYMBOL_GPL(unix_inq_len
);
2121 long unix_outq_len(struct sock
*sk
)
2123 return sk_wmem_alloc_get(sk
);
2125 EXPORT_SYMBOL_GPL(unix_outq_len
);
2127 static int unix_ioctl(struct socket
*sock
, unsigned int cmd
, unsigned long arg
)
2129 struct sock
*sk
= sock
->sk
;
2135 amount
= unix_outq_len(sk
);
2136 err
= put_user(amount
, (int __user
*)arg
);
2139 amount
= unix_inq_len(sk
);
2143 err
= put_user(amount
, (int __user
*)arg
);
2152 static unsigned int unix_poll(struct file
*file
, struct socket
*sock
, poll_table
*wait
)
2154 struct sock
*sk
= sock
->sk
;
2157 sock_poll_wait(file
, sk_sleep(sk
), wait
);
2160 /* exceptional events? */
2163 if (sk
->sk_shutdown
== SHUTDOWN_MASK
)
2165 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
2166 mask
|= POLLRDHUP
| POLLIN
| POLLRDNORM
;
2169 if (!skb_queue_empty(&sk
->sk_receive_queue
))
2170 mask
|= POLLIN
| POLLRDNORM
;
2172 /* Connection-based need to check for termination and startup */
2173 if ((sk
->sk_type
== SOCK_STREAM
|| sk
->sk_type
== SOCK_SEQPACKET
) &&
2174 sk
->sk_state
== TCP_CLOSE
)
2178 * we set writable also when the other side has shut down the
2179 * connection. This prevents stuck sockets.
2181 if (unix_writable(sk
))
2182 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
2187 static unsigned int unix_dgram_poll(struct file
*file
, struct socket
*sock
,
2190 struct sock
*sk
= sock
->sk
, *other
;
2191 unsigned int mask
, writable
;
2193 sock_poll_wait(file
, sk_sleep(sk
), wait
);
2196 /* exceptional events? */
2197 if (sk
->sk_err
|| !skb_queue_empty(&sk
->sk_error_queue
))
2199 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
2200 mask
|= POLLRDHUP
| POLLIN
| POLLRDNORM
;
2201 if (sk
->sk_shutdown
== SHUTDOWN_MASK
)
2205 if (!skb_queue_empty(&sk
->sk_receive_queue
))
2206 mask
|= POLLIN
| POLLRDNORM
;
2208 /* Connection-based need to check for termination and startup */
2209 if (sk
->sk_type
== SOCK_SEQPACKET
) {
2210 if (sk
->sk_state
== TCP_CLOSE
)
2212 /* connection hasn't started yet? */
2213 if (sk
->sk_state
== TCP_SYN_SENT
)
2217 /* No write status requested, avoid expensive OUT tests. */
2218 if (!(poll_requested_events(wait
) & (POLLWRBAND
|POLLWRNORM
|POLLOUT
)))
2221 writable
= unix_writable(sk
);
2222 other
= unix_peer_get(sk
);
2224 if (unix_peer(other
) != sk
) {
2225 sock_poll_wait(file
, &unix_sk(other
)->peer_wait
, wait
);
2226 if (unix_recvq_full(other
))
2233 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
2235 set_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
2240 #ifdef CONFIG_PROC_FS
2241 static struct sock
*first_unix_socket(int *i
)
2243 for (*i
= 0; *i
<= UNIX_HASH_SIZE
; (*i
)++) {
2244 if (!hlist_empty(&unix_socket_table
[*i
]))
2245 return __sk_head(&unix_socket_table
[*i
]);
2250 static struct sock
*next_unix_socket(int *i
, struct sock
*s
)
2252 struct sock
*next
= sk_next(s
);
2253 /* More in this chain? */
2256 /* Look for next non-empty chain. */
2257 for ((*i
)++; *i
<= UNIX_HASH_SIZE
; (*i
)++) {
2258 if (!hlist_empty(&unix_socket_table
[*i
]))
2259 return __sk_head(&unix_socket_table
[*i
]);
2264 struct unix_iter_state
{
2265 struct seq_net_private p
;
2269 static struct sock
*unix_seq_idx(struct seq_file
*seq
, loff_t pos
)
2271 struct unix_iter_state
*iter
= seq
->private;
2275 for (s
= first_unix_socket(&iter
->i
); s
; s
= next_unix_socket(&iter
->i
, s
)) {
2276 if (sock_net(s
) != seq_file_net(seq
))
2285 static void *unix_seq_start(struct seq_file
*seq
, loff_t
*pos
)
2286 __acquires(unix_table_lock
)
2288 spin_lock(&unix_table_lock
);
2289 return *pos
? unix_seq_idx(seq
, *pos
- 1) : SEQ_START_TOKEN
;
2292 static void *unix_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
2294 struct unix_iter_state
*iter
= seq
->private;
2295 struct sock
*sk
= v
;
2298 if (v
== SEQ_START_TOKEN
)
2299 sk
= first_unix_socket(&iter
->i
);
2301 sk
= next_unix_socket(&iter
->i
, sk
);
2302 while (sk
&& (sock_net(sk
) != seq_file_net(seq
)))
2303 sk
= next_unix_socket(&iter
->i
, sk
);
2307 static void unix_seq_stop(struct seq_file
*seq
, void *v
)
2308 __releases(unix_table_lock
)
2310 spin_unlock(&unix_table_lock
);
2313 static int unix_seq_show(struct seq_file
*seq
, void *v
)
2316 if (v
== SEQ_START_TOKEN
)
2317 seq_puts(seq
, "Num RefCount Protocol Flags Type St "
2321 struct unix_sock
*u
= unix_sk(s
);
2324 seq_printf(seq
, "%pK: %08X %08X %08X %04X %02X %5lu",
2326 atomic_read(&s
->sk_refcnt
),
2328 s
->sk_state
== TCP_LISTEN
? __SO_ACCEPTCON
: 0,
2331 (s
->sk_state
== TCP_ESTABLISHED
? SS_CONNECTED
: SS_UNCONNECTED
) :
2332 (s
->sk_state
== TCP_ESTABLISHED
? SS_CONNECTING
: SS_DISCONNECTING
),
2340 len
= u
->addr
->len
- sizeof(short);
2341 if (!UNIX_ABSTRACT(s
))
2347 for ( ; i
< len
; i
++)
2348 seq_putc(seq
, u
->addr
->name
->sun_path
[i
]);
2350 unix_state_unlock(s
);
2351 seq_putc(seq
, '\n');
2357 static const struct seq_operations unix_seq_ops
= {
2358 .start
= unix_seq_start
,
2359 .next
= unix_seq_next
,
2360 .stop
= unix_seq_stop
,
2361 .show
= unix_seq_show
,
2364 static int unix_seq_open(struct inode
*inode
, struct file
*file
)
2366 return seq_open_net(inode
, file
, &unix_seq_ops
,
2367 sizeof(struct unix_iter_state
));
2370 static const struct file_operations unix_seq_fops
= {
2371 .owner
= THIS_MODULE
,
2372 .open
= unix_seq_open
,
2374 .llseek
= seq_lseek
,
2375 .release
= seq_release_net
,
2380 static const struct net_proto_family unix_family_ops
= {
2382 .create
= unix_create
,
2383 .owner
= THIS_MODULE
,
2387 static int __net_init
unix_net_init(struct net
*net
)
2389 int error
= -ENOMEM
;
2391 net
->unx
.sysctl_max_dgram_qlen
= 10;
2392 if (unix_sysctl_register(net
))
2395 #ifdef CONFIG_PROC_FS
2396 if (!proc_net_fops_create(net
, "unix", 0, &unix_seq_fops
)) {
2397 unix_sysctl_unregister(net
);
2406 static void __net_exit
unix_net_exit(struct net
*net
)
2408 unix_sysctl_unregister(net
);
2409 proc_net_remove(net
, "unix");
2412 static struct pernet_operations unix_net_ops
= {
2413 .init
= unix_net_init
,
2414 .exit
= unix_net_exit
,
2417 static int __init
af_unix_init(void)
2420 struct sk_buff
*dummy_skb
;
2422 BUILD_BUG_ON(sizeof(struct unix_skb_parms
) > sizeof(dummy_skb
->cb
));
2424 rc
= proto_register(&unix_proto
, 1);
2426 printk(KERN_CRIT
"%s: Cannot create unix_sock SLAB cache!\n",
2431 sock_register(&unix_family_ops
);
2432 register_pernet_subsys(&unix_net_ops
);
2437 static void __exit
af_unix_exit(void)
2439 sock_unregister(PF_UNIX
);
2440 proto_unregister(&unix_proto
);
2441 unregister_pernet_subsys(&unix_net_ops
);
2444 /* Earlier than device_initcall() so that other drivers invoking
2445 request_module() don't end up in a loop when modprobe tries
2446 to use a UNIX socket. But later than subsys_initcall() because
2447 we depend on stuff initialised there */
2448 fs_initcall(af_unix_init
);
2449 module_exit(af_unix_exit
);
2451 MODULE_LICENSE("GPL");
2452 MODULE_ALIAS_NETPROTO(PF_UNIX
);