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
);
817 static int unix_mknod(const char *sun_path
, umode_t mode
, struct path
*res
)
819 struct dentry
*dentry
;
823 * Get the parent directory, calculate the hash for last
826 dentry
= kern_path_create(AT_FDCWD
, sun_path
, &path
, 0);
827 err
= PTR_ERR(dentry
);
832 * All right, let's create it.
834 err
= security_path_mknod(&path
, dentry
, mode
, 0);
836 err
= vfs_mknod(path
.dentry
->d_inode
, dentry
, mode
, 0);
838 res
->mnt
= mntget(path
.mnt
);
839 res
->dentry
= dget(dentry
);
842 done_path_create(&path
, dentry
);
846 static int unix_bind(struct socket
*sock
, struct sockaddr
*uaddr
, int addr_len
)
848 struct sock
*sk
= sock
->sk
;
849 struct net
*net
= sock_net(sk
);
850 struct unix_sock
*u
= unix_sk(sk
);
851 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)uaddr
;
852 char *sun_path
= sunaddr
->sun_path
;
855 struct unix_address
*addr
;
856 struct hlist_head
*list
;
859 if (sunaddr
->sun_family
!= AF_UNIX
)
862 if (addr_len
== sizeof(short)) {
863 err
= unix_autobind(sock
);
867 err
= unix_mkname(sunaddr
, addr_len
, &hash
);
872 mutex_lock(&u
->readlock
);
879 addr
= kmalloc(sizeof(*addr
)+addr_len
, GFP_KERNEL
);
883 memcpy(addr
->name
, sunaddr
, addr_len
);
884 addr
->len
= addr_len
;
885 addr
->hash
= hash
^ sk
->sk_type
;
886 atomic_set(&addr
->refcnt
, 1);
890 umode_t mode
= S_IFSOCK
|
891 (SOCK_INODE(sock
)->i_mode
& ~current_umask());
892 err
= unix_mknod(sun_path
, mode
, &path
);
896 unix_release_addr(addr
);
899 addr
->hash
= UNIX_HASH_SIZE
;
900 hash
= path
.dentry
->d_inode
->i_ino
& (UNIX_HASH_SIZE
-1);
901 spin_lock(&unix_table_lock
);
903 list
= &unix_socket_table
[hash
];
905 spin_lock(&unix_table_lock
);
907 if (__unix_find_socket_byname(net
, sunaddr
, addr_len
,
908 sk
->sk_type
, hash
)) {
909 unix_release_addr(addr
);
913 list
= &unix_socket_table
[addr
->hash
];
917 __unix_remove_socket(sk
);
919 __unix_insert_socket(list
, sk
);
922 spin_unlock(&unix_table_lock
);
924 mutex_unlock(&u
->readlock
);
929 static void unix_state_double_lock(struct sock
*sk1
, struct sock
*sk2
)
931 if (unlikely(sk1
== sk2
) || !sk2
) {
932 unix_state_lock(sk1
);
936 unix_state_lock(sk1
);
937 unix_state_lock_nested(sk2
);
939 unix_state_lock(sk2
);
940 unix_state_lock_nested(sk1
);
944 static void unix_state_double_unlock(struct sock
*sk1
, struct sock
*sk2
)
946 if (unlikely(sk1
== sk2
) || !sk2
) {
947 unix_state_unlock(sk1
);
950 unix_state_unlock(sk1
);
951 unix_state_unlock(sk2
);
954 static int unix_dgram_connect(struct socket
*sock
, struct sockaddr
*addr
,
957 struct sock
*sk
= sock
->sk
;
958 struct net
*net
= sock_net(sk
);
959 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)addr
;
964 if (addr
->sa_family
!= AF_UNSPEC
) {
965 err
= unix_mkname(sunaddr
, alen
, &hash
);
970 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) &&
971 !unix_sk(sk
)->addr
&& (err
= unix_autobind(sock
)) != 0)
975 other
= unix_find_other(net
, sunaddr
, alen
, sock
->type
, hash
, &err
);
979 unix_state_double_lock(sk
, other
);
981 /* Apparently VFS overslept socket death. Retry. */
982 if (sock_flag(other
, SOCK_DEAD
)) {
983 unix_state_double_unlock(sk
, other
);
989 if (!unix_may_send(sk
, other
))
992 err
= security_unix_may_send(sk
->sk_socket
, other
->sk_socket
);
998 * 1003.1g breaking connected state with AF_UNSPEC
1001 unix_state_double_lock(sk
, other
);
1005 * If it was connected, reconnect.
1007 if (unix_peer(sk
)) {
1008 struct sock
*old_peer
= unix_peer(sk
);
1009 unix_peer(sk
) = other
;
1010 unix_state_double_unlock(sk
, other
);
1012 if (other
!= old_peer
)
1013 unix_dgram_disconnected(sk
, old_peer
);
1016 unix_peer(sk
) = other
;
1017 unix_state_double_unlock(sk
, other
);
1022 unix_state_double_unlock(sk
, other
);
1028 static long unix_wait_for_peer(struct sock
*other
, long timeo
)
1030 struct unix_sock
*u
= unix_sk(other
);
1034 prepare_to_wait_exclusive(&u
->peer_wait
, &wait
, TASK_INTERRUPTIBLE
);
1036 sched
= !sock_flag(other
, SOCK_DEAD
) &&
1037 !(other
->sk_shutdown
& RCV_SHUTDOWN
) &&
1038 unix_recvq_full(other
);
1040 unix_state_unlock(other
);
1043 timeo
= schedule_timeout(timeo
);
1045 finish_wait(&u
->peer_wait
, &wait
);
1049 static int unix_stream_connect(struct socket
*sock
, struct sockaddr
*uaddr
,
1050 int addr_len
, int flags
)
1052 struct sockaddr_un
*sunaddr
= (struct sockaddr_un
*)uaddr
;
1053 struct sock
*sk
= sock
->sk
;
1054 struct net
*net
= sock_net(sk
);
1055 struct unix_sock
*u
= unix_sk(sk
), *newu
, *otheru
;
1056 struct sock
*newsk
= NULL
;
1057 struct sock
*other
= NULL
;
1058 struct sk_buff
*skb
= NULL
;
1064 err
= unix_mkname(sunaddr
, addr_len
, &hash
);
1069 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) && !u
->addr
&&
1070 (err
= unix_autobind(sock
)) != 0)
1073 timeo
= sock_sndtimeo(sk
, flags
& O_NONBLOCK
);
1075 /* First of all allocate resources.
1076 If we will make it after state is locked,
1077 we will have to recheck all again in any case.
1082 /* create new sock for complete connection */
1083 newsk
= unix_create1(sock_net(sk
), NULL
);
1087 /* Allocate skb for sending to listening sock */
1088 skb
= sock_wmalloc(newsk
, 1, 0, GFP_KERNEL
);
1093 /* Find listening sock. */
1094 other
= unix_find_other(net
, sunaddr
, addr_len
, sk
->sk_type
, hash
, &err
);
1098 /* Latch state of peer */
1099 unix_state_lock(other
);
1101 /* Apparently VFS overslept socket death. Retry. */
1102 if (sock_flag(other
, SOCK_DEAD
)) {
1103 unix_state_unlock(other
);
1108 err
= -ECONNREFUSED
;
1109 if (other
->sk_state
!= TCP_LISTEN
)
1111 if (other
->sk_shutdown
& RCV_SHUTDOWN
)
1114 if (unix_recvq_full(other
)) {
1119 timeo
= unix_wait_for_peer(other
, timeo
);
1121 err
= sock_intr_errno(timeo
);
1122 if (signal_pending(current
))
1130 It is tricky place. We need to grab our state lock and cannot
1131 drop lock on peer. It is dangerous because deadlock is
1132 possible. Connect to self case and simultaneous
1133 attempt to connect are eliminated by checking socket
1134 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1135 check this before attempt to grab lock.
1137 Well, and we have to recheck the state after socket locked.
1143 /* This is ok... continue with connect */
1145 case TCP_ESTABLISHED
:
1146 /* Socket is already connected */
1154 unix_state_lock_nested(sk
);
1156 if (sk
->sk_state
!= st
) {
1157 unix_state_unlock(sk
);
1158 unix_state_unlock(other
);
1163 err
= security_unix_stream_connect(sk
, other
, newsk
);
1165 unix_state_unlock(sk
);
1169 /* The way is open! Fastly set all the necessary fields... */
1172 unix_peer(newsk
) = sk
;
1173 newsk
->sk_state
= TCP_ESTABLISHED
;
1174 newsk
->sk_type
= sk
->sk_type
;
1175 init_peercred(newsk
);
1176 newu
= unix_sk(newsk
);
1177 RCU_INIT_POINTER(newsk
->sk_wq
, &newu
->peer_wq
);
1178 otheru
= unix_sk(other
);
1180 /* copy address information from listening to new sock*/
1182 atomic_inc(&otheru
->addr
->refcnt
);
1183 newu
->addr
= otheru
->addr
;
1185 if (otheru
->path
.dentry
) {
1186 path_get(&otheru
->path
);
1187 newu
->path
= otheru
->path
;
1190 /* Set credentials */
1191 copy_peercred(sk
, other
);
1193 sock
->state
= SS_CONNECTED
;
1194 sk
->sk_state
= TCP_ESTABLISHED
;
1197 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1198 unix_peer(sk
) = newsk
;
1200 unix_state_unlock(sk
);
1202 /* take ten and and send info to listening sock */
1203 spin_lock(&other
->sk_receive_queue
.lock
);
1204 __skb_queue_tail(&other
->sk_receive_queue
, skb
);
1205 spin_unlock(&other
->sk_receive_queue
.lock
);
1206 unix_state_unlock(other
);
1207 other
->sk_data_ready(other
, 0);
1213 unix_state_unlock(other
);
1218 unix_release_sock(newsk
, 0);
1224 static int unix_socketpair(struct socket
*socka
, struct socket
*sockb
)
1226 struct sock
*ska
= socka
->sk
, *skb
= sockb
->sk
;
1228 /* Join our sockets back to back */
1231 unix_peer(ska
) = skb
;
1232 unix_peer(skb
) = ska
;
1236 if (ska
->sk_type
!= SOCK_DGRAM
) {
1237 ska
->sk_state
= TCP_ESTABLISHED
;
1238 skb
->sk_state
= TCP_ESTABLISHED
;
1239 socka
->state
= SS_CONNECTED
;
1240 sockb
->state
= SS_CONNECTED
;
1245 static int unix_accept(struct socket
*sock
, struct socket
*newsock
, int flags
)
1247 struct sock
*sk
= sock
->sk
;
1249 struct sk_buff
*skb
;
1253 if (sock
->type
!= SOCK_STREAM
&& sock
->type
!= SOCK_SEQPACKET
)
1257 if (sk
->sk_state
!= TCP_LISTEN
)
1260 /* If socket state is TCP_LISTEN it cannot change (for now...),
1261 * so that no locks are necessary.
1264 skb
= skb_recv_datagram(sk
, 0, flags
&O_NONBLOCK
, &err
);
1266 /* This means receive shutdown. */
1273 skb_free_datagram(sk
, skb
);
1274 wake_up_interruptible(&unix_sk(sk
)->peer_wait
);
1276 /* attach accepted sock to socket */
1277 unix_state_lock(tsk
);
1278 newsock
->state
= SS_CONNECTED
;
1279 sock_graft(tsk
, newsock
);
1280 unix_state_unlock(tsk
);
1288 static int unix_getname(struct socket
*sock
, struct sockaddr
*uaddr
, int *uaddr_len
, int peer
)
1290 struct sock
*sk
= sock
->sk
;
1291 struct unix_sock
*u
;
1292 DECLARE_SOCKADDR(struct sockaddr_un
*, sunaddr
, uaddr
);
1296 sk
= unix_peer_get(sk
);
1307 unix_state_lock(sk
);
1309 sunaddr
->sun_family
= AF_UNIX
;
1310 sunaddr
->sun_path
[0] = 0;
1311 *uaddr_len
= sizeof(short);
1313 struct unix_address
*addr
= u
->addr
;
1315 *uaddr_len
= addr
->len
;
1316 memcpy(sunaddr
, addr
->name
, *uaddr_len
);
1318 unix_state_unlock(sk
);
1324 static void unix_detach_fds(struct scm_cookie
*scm
, struct sk_buff
*skb
)
1328 scm
->fp
= UNIXCB(skb
).fp
;
1329 UNIXCB(skb
).fp
= NULL
;
1331 for (i
= scm
->fp
->count
-1; i
>= 0; i
--)
1332 unix_notinflight(scm
->fp
->fp
[i
]);
1335 static void unix_destruct_scm(struct sk_buff
*skb
)
1337 struct scm_cookie scm
;
1338 memset(&scm
, 0, sizeof(scm
));
1339 scm
.pid
= UNIXCB(skb
).pid
;
1340 scm
.cred
= UNIXCB(skb
).cred
;
1342 unix_detach_fds(&scm
, skb
);
1344 /* Alas, it calls VFS */
1345 /* So fscking what? fput() had been SMP-safe since the last Summer */
1350 #define MAX_RECURSION_LEVEL 4
1352 static int unix_attach_fds(struct scm_cookie
*scm
, struct sk_buff
*skb
)
1355 unsigned char max_level
= 0;
1356 int unix_sock_count
= 0;
1358 for (i
= scm
->fp
->count
- 1; i
>= 0; i
--) {
1359 struct sock
*sk
= unix_get_socket(scm
->fp
->fp
[i
]);
1363 max_level
= max(max_level
,
1364 unix_sk(sk
)->recursion_level
);
1367 if (unlikely(max_level
> MAX_RECURSION_LEVEL
))
1368 return -ETOOMANYREFS
;
1371 * Need to duplicate file references for the sake of garbage
1372 * collection. Otherwise a socket in the fps might become a
1373 * candidate for GC while the skb is not yet queued.
1375 UNIXCB(skb
).fp
= scm_fp_dup(scm
->fp
);
1376 if (!UNIXCB(skb
).fp
)
1379 if (unix_sock_count
) {
1380 for (i
= scm
->fp
->count
- 1; i
>= 0; i
--)
1381 unix_inflight(scm
->fp
->fp
[i
]);
1386 static int unix_scm_to_skb(struct scm_cookie
*scm
, struct sk_buff
*skb
, bool send_fds
)
1390 UNIXCB(skb
).pid
= get_pid(scm
->pid
);
1392 UNIXCB(skb
).cred
= get_cred(scm
->cred
);
1393 UNIXCB(skb
).fp
= NULL
;
1394 if (scm
->fp
&& send_fds
)
1395 err
= unix_attach_fds(scm
, skb
);
1397 skb
->destructor
= unix_destruct_scm
;
1402 * Some apps rely on write() giving SCM_CREDENTIALS
1403 * We include credentials if source or destination socket
1404 * asserted SOCK_PASSCRED.
1406 static void maybe_add_creds(struct sk_buff
*skb
, const struct socket
*sock
,
1407 const struct sock
*other
)
1409 if (UNIXCB(skb
).cred
)
1411 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) ||
1412 !other
->sk_socket
||
1413 test_bit(SOCK_PASSCRED
, &other
->sk_socket
->flags
)) {
1414 UNIXCB(skb
).pid
= get_pid(task_tgid(current
));
1415 UNIXCB(skb
).cred
= get_current_cred();
1420 * Send AF_UNIX data.
1423 static int unix_dgram_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1424 struct msghdr
*msg
, size_t len
)
1426 struct sock_iocb
*siocb
= kiocb_to_siocb(kiocb
);
1427 struct sock
*sk
= sock
->sk
;
1428 struct net
*net
= sock_net(sk
);
1429 struct unix_sock
*u
= unix_sk(sk
);
1430 struct sockaddr_un
*sunaddr
= msg
->msg_name
;
1431 struct sock
*other
= NULL
;
1432 int namelen
= 0; /* fake GCC */
1435 struct sk_buff
*skb
;
1437 struct scm_cookie tmp_scm
;
1441 if (NULL
== siocb
->scm
)
1442 siocb
->scm
= &tmp_scm
;
1444 err
= scm_send(sock
, msg
, siocb
->scm
);
1449 if (msg
->msg_flags
&MSG_OOB
)
1452 if (msg
->msg_namelen
) {
1453 err
= unix_mkname(sunaddr
, msg
->msg_namelen
, &hash
);
1460 other
= unix_peer_get(sk
);
1465 if (test_bit(SOCK_PASSCRED
, &sock
->flags
) && !u
->addr
1466 && (err
= unix_autobind(sock
)) != 0)
1470 if (len
> sk
->sk_sndbuf
- 32)
1473 if (len
> SKB_MAX_ALLOC
)
1474 data_len
= min_t(size_t,
1475 len
- SKB_MAX_ALLOC
,
1476 MAX_SKB_FRAGS
* PAGE_SIZE
);
1478 skb
= sock_alloc_send_pskb(sk
, len
- data_len
, data_len
,
1479 msg
->msg_flags
& MSG_DONTWAIT
, &err
);
1483 err
= unix_scm_to_skb(siocb
->scm
, skb
, true);
1486 max_level
= err
+ 1;
1487 unix_get_secdata(siocb
->scm
, skb
);
1489 skb_put(skb
, len
- data_len
);
1490 skb
->data_len
= data_len
;
1492 err
= skb_copy_datagram_from_iovec(skb
, 0, msg
->msg_iov
, 0, len
);
1496 timeo
= sock_sndtimeo(sk
, msg
->msg_flags
& MSG_DONTWAIT
);
1501 if (sunaddr
== NULL
)
1504 other
= unix_find_other(net
, sunaddr
, namelen
, sk
->sk_type
,
1510 if (sk_filter(other
, skb
) < 0) {
1511 /* Toss the packet but do not return any error to the sender */
1516 unix_state_lock(other
);
1518 if (!unix_may_send(sk
, other
))
1521 if (sock_flag(other
, SOCK_DEAD
)) {
1523 * Check with 1003.1g - what should
1526 unix_state_unlock(other
);
1530 unix_state_lock(sk
);
1531 if (unix_peer(sk
) == other
) {
1532 unix_peer(sk
) = NULL
;
1533 unix_state_unlock(sk
);
1535 unix_dgram_disconnected(sk
, other
);
1537 err
= -ECONNREFUSED
;
1539 unix_state_unlock(sk
);
1549 if (other
->sk_shutdown
& RCV_SHUTDOWN
)
1552 if (sk
->sk_type
!= SOCK_SEQPACKET
) {
1553 err
= security_unix_may_send(sk
->sk_socket
, other
->sk_socket
);
1558 if (unix_peer(other
) != sk
&& unix_recvq_full(other
)) {
1564 timeo
= unix_wait_for_peer(other
, timeo
);
1566 err
= sock_intr_errno(timeo
);
1567 if (signal_pending(current
))
1573 if (sock_flag(other
, SOCK_RCVTSTAMP
))
1574 __net_timestamp(skb
);
1575 maybe_add_creds(skb
, sock
, other
);
1576 skb_queue_tail(&other
->sk_receive_queue
, skb
);
1577 if (max_level
> unix_sk(other
)->recursion_level
)
1578 unix_sk(other
)->recursion_level
= max_level
;
1579 unix_state_unlock(other
);
1580 other
->sk_data_ready(other
, len
);
1582 scm_destroy(siocb
->scm
);
1586 unix_state_unlock(other
);
1592 scm_destroy(siocb
->scm
);
1597 static int unix_stream_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1598 struct msghdr
*msg
, size_t len
)
1600 struct sock_iocb
*siocb
= kiocb_to_siocb(kiocb
);
1601 struct sock
*sk
= sock
->sk
;
1602 struct sock
*other
= NULL
;
1604 struct sk_buff
*skb
;
1606 struct scm_cookie tmp_scm
;
1607 bool fds_sent
= false;
1610 if (NULL
== siocb
->scm
)
1611 siocb
->scm
= &tmp_scm
;
1613 err
= scm_send(sock
, msg
, siocb
->scm
);
1618 if (msg
->msg_flags
&MSG_OOB
)
1621 if (msg
->msg_namelen
) {
1622 err
= sk
->sk_state
== TCP_ESTABLISHED
? -EISCONN
: -EOPNOTSUPP
;
1626 other
= unix_peer(sk
);
1631 if (sk
->sk_shutdown
& SEND_SHUTDOWN
)
1634 while (sent
< len
) {
1636 * Optimisation for the fact that under 0.01% of X
1637 * messages typically need breaking up.
1642 /* Keep two messages in the pipe so it schedules better */
1643 if (size
> ((sk
->sk_sndbuf
>> 1) - 64))
1644 size
= (sk
->sk_sndbuf
>> 1) - 64;
1646 if (size
> SKB_MAX_ALLOC
)
1647 size
= SKB_MAX_ALLOC
;
1653 skb
= sock_alloc_send_skb(sk
, size
, msg
->msg_flags
&MSG_DONTWAIT
,
1660 * If you pass two values to the sock_alloc_send_skb
1661 * it tries to grab the large buffer with GFP_NOFS
1662 * (which can fail easily), and if it fails grab the
1663 * fallback size buffer which is under a page and will
1666 size
= min_t(int, size
, skb_tailroom(skb
));
1669 /* Only send the fds in the first buffer */
1670 err
= unix_scm_to_skb(siocb
->scm
, skb
, !fds_sent
);
1675 max_level
= err
+ 1;
1678 err
= memcpy_fromiovec(skb_put(skb
, size
), msg
->msg_iov
, size
);
1684 unix_state_lock(other
);
1686 if (sock_flag(other
, SOCK_DEAD
) ||
1687 (other
->sk_shutdown
& RCV_SHUTDOWN
))
1690 maybe_add_creds(skb
, sock
, other
);
1691 skb_queue_tail(&other
->sk_receive_queue
, skb
);
1692 if (max_level
> unix_sk(other
)->recursion_level
)
1693 unix_sk(other
)->recursion_level
= max_level
;
1694 unix_state_unlock(other
);
1695 other
->sk_data_ready(other
, size
);
1699 scm_destroy(siocb
->scm
);
1705 unix_state_unlock(other
);
1708 if (sent
== 0 && !(msg
->msg_flags
&MSG_NOSIGNAL
))
1709 send_sig(SIGPIPE
, current
, 0);
1712 scm_destroy(siocb
->scm
);
1714 return sent
? : err
;
1717 static int unix_seqpacket_sendmsg(struct kiocb
*kiocb
, struct socket
*sock
,
1718 struct msghdr
*msg
, size_t len
)
1721 struct sock
*sk
= sock
->sk
;
1723 err
= sock_error(sk
);
1727 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1730 if (msg
->msg_namelen
)
1731 msg
->msg_namelen
= 0;
1733 return unix_dgram_sendmsg(kiocb
, sock
, msg
, len
);
1736 static int unix_seqpacket_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1737 struct msghdr
*msg
, size_t size
,
1740 struct sock
*sk
= sock
->sk
;
1742 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1745 return unix_dgram_recvmsg(iocb
, sock
, msg
, size
, flags
);
1748 static void unix_copy_addr(struct msghdr
*msg
, struct sock
*sk
)
1750 struct unix_sock
*u
= unix_sk(sk
);
1752 msg
->msg_namelen
= 0;
1754 msg
->msg_namelen
= u
->addr
->len
;
1755 memcpy(msg
->msg_name
, u
->addr
->name
, u
->addr
->len
);
1759 static int unix_dgram_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1760 struct msghdr
*msg
, size_t size
,
1763 struct sock_iocb
*siocb
= kiocb_to_siocb(iocb
);
1764 struct scm_cookie tmp_scm
;
1765 struct sock
*sk
= sock
->sk
;
1766 struct unix_sock
*u
= unix_sk(sk
);
1767 int noblock
= flags
& MSG_DONTWAIT
;
1768 struct sk_buff
*skb
;
1776 msg
->msg_namelen
= 0;
1778 err
= mutex_lock_interruptible(&u
->readlock
);
1780 err
= sock_intr_errno(sock_rcvtimeo(sk
, noblock
));
1784 skip
= sk_peek_offset(sk
, flags
);
1786 skb
= __skb_recv_datagram(sk
, flags
, &peeked
, &skip
, &err
);
1788 unix_state_lock(sk
);
1789 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1790 if (sk
->sk_type
== SOCK_SEQPACKET
&& err
== -EAGAIN
&&
1791 (sk
->sk_shutdown
& RCV_SHUTDOWN
))
1793 unix_state_unlock(sk
);
1797 wake_up_interruptible_sync_poll(&u
->peer_wait
,
1798 POLLOUT
| POLLWRNORM
| POLLWRBAND
);
1801 unix_copy_addr(msg
, skb
->sk
);
1803 if (size
> skb
->len
- skip
)
1804 size
= skb
->len
- skip
;
1805 else if (size
< skb
->len
- skip
)
1806 msg
->msg_flags
|= MSG_TRUNC
;
1808 err
= skb_copy_datagram_iovec(skb
, skip
, msg
->msg_iov
, size
);
1812 if (sock_flag(sk
, SOCK_RCVTSTAMP
))
1813 __sock_recv_timestamp(msg
, sk
, skb
);
1816 siocb
->scm
= &tmp_scm
;
1817 memset(&tmp_scm
, 0, sizeof(tmp_scm
));
1819 scm_set_cred(siocb
->scm
, UNIXCB(skb
).pid
, UNIXCB(skb
).cred
);
1820 unix_set_secdata(siocb
->scm
, skb
);
1822 if (!(flags
& MSG_PEEK
)) {
1824 unix_detach_fds(siocb
->scm
, skb
);
1826 sk_peek_offset_bwd(sk
, skb
->len
);
1828 /* It is questionable: on PEEK we could:
1829 - do not return fds - good, but too simple 8)
1830 - return fds, and do not return them on read (old strategy,
1832 - clone fds (I chose it for now, it is the most universal
1835 POSIX 1003.1g does not actually define this clearly
1836 at all. POSIX 1003.1g doesn't define a lot of things
1841 sk_peek_offset_fwd(sk
, size
);
1844 siocb
->scm
->fp
= scm_fp_dup(UNIXCB(skb
).fp
);
1846 err
= (flags
& MSG_TRUNC
) ? skb
->len
- skip
: size
;
1848 scm_recv(sock
, msg
, siocb
->scm
, flags
);
1851 skb_free_datagram(sk
, skb
);
1853 mutex_unlock(&u
->readlock
);
1859 * Sleep until data has arrive. But check for races..
1862 static long unix_stream_data_wait(struct sock
*sk
, long timeo
)
1866 unix_state_lock(sk
);
1869 prepare_to_wait(sk_sleep(sk
), &wait
, TASK_INTERRUPTIBLE
);
1871 if (!skb_queue_empty(&sk
->sk_receive_queue
) ||
1873 (sk
->sk_shutdown
& RCV_SHUTDOWN
) ||
1874 signal_pending(current
) ||
1878 set_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
1879 unix_state_unlock(sk
);
1880 timeo
= schedule_timeout(timeo
);
1881 unix_state_lock(sk
);
1882 clear_bit(SOCK_ASYNC_WAITDATA
, &sk
->sk_socket
->flags
);
1885 finish_wait(sk_sleep(sk
), &wait
);
1886 unix_state_unlock(sk
);
1892 static int unix_stream_recvmsg(struct kiocb
*iocb
, struct socket
*sock
,
1893 struct msghdr
*msg
, size_t size
,
1896 struct sock_iocb
*siocb
= kiocb_to_siocb(iocb
);
1897 struct scm_cookie tmp_scm
;
1898 struct sock
*sk
= sock
->sk
;
1899 struct unix_sock
*u
= unix_sk(sk
);
1900 struct sockaddr_un
*sunaddr
= msg
->msg_name
;
1902 int check_creds
= 0;
1909 if (sk
->sk_state
!= TCP_ESTABLISHED
)
1916 target
= sock_rcvlowat(sk
, flags
&MSG_WAITALL
, size
);
1917 timeo
= sock_rcvtimeo(sk
, flags
&MSG_DONTWAIT
);
1919 msg
->msg_namelen
= 0;
1921 /* Lock the socket to prevent queue disordering
1922 * while sleeps in memcpy_tomsg
1926 siocb
->scm
= &tmp_scm
;
1927 memset(&tmp_scm
, 0, sizeof(tmp_scm
));
1930 err
= mutex_lock_interruptible(&u
->readlock
);
1932 err
= sock_intr_errno(timeo
);
1936 skip
= sk_peek_offset(sk
, flags
);
1940 struct sk_buff
*skb
;
1942 unix_state_lock(sk
);
1943 skb
= skb_peek(&sk
->sk_receive_queue
);
1946 unix_sk(sk
)->recursion_level
= 0;
1947 if (copied
>= target
)
1951 * POSIX 1003.1g mandates this order.
1954 err
= sock_error(sk
);
1957 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
1960 unix_state_unlock(sk
);
1964 mutex_unlock(&u
->readlock
);
1966 timeo
= unix_stream_data_wait(sk
, timeo
);
1968 if (signal_pending(current
)
1969 || mutex_lock_interruptible(&u
->readlock
)) {
1970 err
= sock_intr_errno(timeo
);
1976 unix_state_unlock(sk
);
1980 if (skip
>= skb
->len
) {
1982 skb
= skb_peek_next(skb
, &sk
->sk_receive_queue
);
1986 unix_state_unlock(sk
);
1989 /* Never glue messages from different writers */
1990 if ((UNIXCB(skb
).pid
!= siocb
->scm
->pid
) ||
1991 (UNIXCB(skb
).cred
!= siocb
->scm
->cred
))
1994 /* Copy credentials */
1995 scm_set_cred(siocb
->scm
, UNIXCB(skb
).pid
, UNIXCB(skb
).cred
);
1999 /* Copy address just once */
2001 unix_copy_addr(msg
, skb
->sk
);
2005 chunk
= min_t(unsigned int, skb
->len
- skip
, size
);
2006 if (memcpy_toiovec(msg
->msg_iov
, skb
->data
+ skip
, chunk
)) {
2014 /* Mark read part of skb as used */
2015 if (!(flags
& MSG_PEEK
)) {
2016 skb_pull(skb
, chunk
);
2018 sk_peek_offset_bwd(sk
, chunk
);
2021 unix_detach_fds(siocb
->scm
, skb
);
2026 skb_unlink(skb
, &sk
->sk_receive_queue
);
2032 /* It is questionable, see note in unix_dgram_recvmsg.
2035 siocb
->scm
->fp
= scm_fp_dup(UNIXCB(skb
).fp
);
2037 sk_peek_offset_fwd(sk
, chunk
);
2043 mutex_unlock(&u
->readlock
);
2044 scm_recv(sock
, msg
, siocb
->scm
, flags
);
2046 return copied
? : err
;
2049 static int unix_shutdown(struct socket
*sock
, int mode
)
2051 struct sock
*sk
= sock
->sk
;
2054 mode
= (mode
+1)&(RCV_SHUTDOWN
|SEND_SHUTDOWN
);
2059 unix_state_lock(sk
);
2060 sk
->sk_shutdown
|= mode
;
2061 other
= unix_peer(sk
);
2064 unix_state_unlock(sk
);
2065 sk
->sk_state_change(sk
);
2068 (sk
->sk_type
== SOCK_STREAM
|| sk
->sk_type
== SOCK_SEQPACKET
)) {
2072 if (mode
&RCV_SHUTDOWN
)
2073 peer_mode
|= SEND_SHUTDOWN
;
2074 if (mode
&SEND_SHUTDOWN
)
2075 peer_mode
|= RCV_SHUTDOWN
;
2076 unix_state_lock(other
);
2077 other
->sk_shutdown
|= peer_mode
;
2078 unix_state_unlock(other
);
2079 other
->sk_state_change(other
);
2080 if (peer_mode
== SHUTDOWN_MASK
)
2081 sk_wake_async(other
, SOCK_WAKE_WAITD
, POLL_HUP
);
2082 else if (peer_mode
& RCV_SHUTDOWN
)
2083 sk_wake_async(other
, SOCK_WAKE_WAITD
, POLL_IN
);
2091 long unix_inq_len(struct sock
*sk
)
2093 struct sk_buff
*skb
;
2096 if (sk
->sk_state
== TCP_LISTEN
)
2099 spin_lock(&sk
->sk_receive_queue
.lock
);
2100 if (sk
->sk_type
== SOCK_STREAM
||
2101 sk
->sk_type
== SOCK_SEQPACKET
) {
2102 skb_queue_walk(&sk
->sk_receive_queue
, skb
)
2105 skb
= skb_peek(&sk
->sk_receive_queue
);
2109 spin_unlock(&sk
->sk_receive_queue
.lock
);
2113 EXPORT_SYMBOL_GPL(unix_inq_len
);
2115 long unix_outq_len(struct sock
*sk
)
2117 return sk_wmem_alloc_get(sk
);
2119 EXPORT_SYMBOL_GPL(unix_outq_len
);
2121 static int unix_ioctl(struct socket
*sock
, unsigned int cmd
, unsigned long arg
)
2123 struct sock
*sk
= sock
->sk
;
2129 amount
= unix_outq_len(sk
);
2130 err
= put_user(amount
, (int __user
*)arg
);
2133 amount
= unix_inq_len(sk
);
2137 err
= put_user(amount
, (int __user
*)arg
);
2146 static unsigned int unix_poll(struct file
*file
, struct socket
*sock
, poll_table
*wait
)
2148 struct sock
*sk
= sock
->sk
;
2151 sock_poll_wait(file
, sk_sleep(sk
), wait
);
2154 /* exceptional events? */
2157 if (sk
->sk_shutdown
== SHUTDOWN_MASK
)
2159 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
2160 mask
|= POLLRDHUP
| POLLIN
| POLLRDNORM
;
2163 if (!skb_queue_empty(&sk
->sk_receive_queue
))
2164 mask
|= POLLIN
| POLLRDNORM
;
2166 /* Connection-based need to check for termination and startup */
2167 if ((sk
->sk_type
== SOCK_STREAM
|| sk
->sk_type
== SOCK_SEQPACKET
) &&
2168 sk
->sk_state
== TCP_CLOSE
)
2172 * we set writable also when the other side has shut down the
2173 * connection. This prevents stuck sockets.
2175 if (unix_writable(sk
))
2176 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
2181 static unsigned int unix_dgram_poll(struct file
*file
, struct socket
*sock
,
2184 struct sock
*sk
= sock
->sk
, *other
;
2185 unsigned int mask
, writable
;
2187 sock_poll_wait(file
, sk_sleep(sk
), wait
);
2190 /* exceptional events? */
2191 if (sk
->sk_err
|| !skb_queue_empty(&sk
->sk_error_queue
))
2193 if (sk
->sk_shutdown
& RCV_SHUTDOWN
)
2194 mask
|= POLLRDHUP
| POLLIN
| POLLRDNORM
;
2195 if (sk
->sk_shutdown
== SHUTDOWN_MASK
)
2199 if (!skb_queue_empty(&sk
->sk_receive_queue
))
2200 mask
|= POLLIN
| POLLRDNORM
;
2202 /* Connection-based need to check for termination and startup */
2203 if (sk
->sk_type
== SOCK_SEQPACKET
) {
2204 if (sk
->sk_state
== TCP_CLOSE
)
2206 /* connection hasn't started yet? */
2207 if (sk
->sk_state
== TCP_SYN_SENT
)
2211 /* No write status requested, avoid expensive OUT tests. */
2212 if (!(poll_requested_events(wait
) & (POLLWRBAND
|POLLWRNORM
|POLLOUT
)))
2215 writable
= unix_writable(sk
);
2216 other
= unix_peer_get(sk
);
2218 if (unix_peer(other
) != sk
) {
2219 sock_poll_wait(file
, &unix_sk(other
)->peer_wait
, wait
);
2220 if (unix_recvq_full(other
))
2227 mask
|= POLLOUT
| POLLWRNORM
| POLLWRBAND
;
2229 set_bit(SOCK_ASYNC_NOSPACE
, &sk
->sk_socket
->flags
);
2234 #ifdef CONFIG_PROC_FS
2235 static struct sock
*first_unix_socket(int *i
)
2237 for (*i
= 0; *i
<= UNIX_HASH_SIZE
; (*i
)++) {
2238 if (!hlist_empty(&unix_socket_table
[*i
]))
2239 return __sk_head(&unix_socket_table
[*i
]);
2244 static struct sock
*next_unix_socket(int *i
, struct sock
*s
)
2246 struct sock
*next
= sk_next(s
);
2247 /* More in this chain? */
2250 /* Look for next non-empty chain. */
2251 for ((*i
)++; *i
<= UNIX_HASH_SIZE
; (*i
)++) {
2252 if (!hlist_empty(&unix_socket_table
[*i
]))
2253 return __sk_head(&unix_socket_table
[*i
]);
2258 struct unix_iter_state
{
2259 struct seq_net_private p
;
2263 static struct sock
*unix_seq_idx(struct seq_file
*seq
, loff_t pos
)
2265 struct unix_iter_state
*iter
= seq
->private;
2269 for (s
= first_unix_socket(&iter
->i
); s
; s
= next_unix_socket(&iter
->i
, s
)) {
2270 if (sock_net(s
) != seq_file_net(seq
))
2279 static void *unix_seq_start(struct seq_file
*seq
, loff_t
*pos
)
2280 __acquires(unix_table_lock
)
2282 spin_lock(&unix_table_lock
);
2283 return *pos
? unix_seq_idx(seq
, *pos
- 1) : SEQ_START_TOKEN
;
2286 static void *unix_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
2288 struct unix_iter_state
*iter
= seq
->private;
2289 struct sock
*sk
= v
;
2292 if (v
== SEQ_START_TOKEN
)
2293 sk
= first_unix_socket(&iter
->i
);
2295 sk
= next_unix_socket(&iter
->i
, sk
);
2296 while (sk
&& (sock_net(sk
) != seq_file_net(seq
)))
2297 sk
= next_unix_socket(&iter
->i
, sk
);
2301 static void unix_seq_stop(struct seq_file
*seq
, void *v
)
2302 __releases(unix_table_lock
)
2304 spin_unlock(&unix_table_lock
);
2307 static int unix_seq_show(struct seq_file
*seq
, void *v
)
2310 if (v
== SEQ_START_TOKEN
)
2311 seq_puts(seq
, "Num RefCount Protocol Flags Type St "
2315 struct unix_sock
*u
= unix_sk(s
);
2318 seq_printf(seq
, "%pK: %08X %08X %08X %04X %02X %5lu",
2320 atomic_read(&s
->sk_refcnt
),
2322 s
->sk_state
== TCP_LISTEN
? __SO_ACCEPTCON
: 0,
2325 (s
->sk_state
== TCP_ESTABLISHED
? SS_CONNECTED
: SS_UNCONNECTED
) :
2326 (s
->sk_state
== TCP_ESTABLISHED
? SS_CONNECTING
: SS_DISCONNECTING
),
2334 len
= u
->addr
->len
- sizeof(short);
2335 if (!UNIX_ABSTRACT(s
))
2341 for ( ; i
< len
; i
++)
2342 seq_putc(seq
, u
->addr
->name
->sun_path
[i
]);
2344 unix_state_unlock(s
);
2345 seq_putc(seq
, '\n');
2351 static const struct seq_operations unix_seq_ops
= {
2352 .start
= unix_seq_start
,
2353 .next
= unix_seq_next
,
2354 .stop
= unix_seq_stop
,
2355 .show
= unix_seq_show
,
2358 static int unix_seq_open(struct inode
*inode
, struct file
*file
)
2360 return seq_open_net(inode
, file
, &unix_seq_ops
,
2361 sizeof(struct unix_iter_state
));
2364 static const struct file_operations unix_seq_fops
= {
2365 .owner
= THIS_MODULE
,
2366 .open
= unix_seq_open
,
2368 .llseek
= seq_lseek
,
2369 .release
= seq_release_net
,
2374 static const struct net_proto_family unix_family_ops
= {
2376 .create
= unix_create
,
2377 .owner
= THIS_MODULE
,
2381 static int __net_init
unix_net_init(struct net
*net
)
2383 int error
= -ENOMEM
;
2385 net
->unx
.sysctl_max_dgram_qlen
= 10;
2386 if (unix_sysctl_register(net
))
2389 #ifdef CONFIG_PROC_FS
2390 if (!proc_net_fops_create(net
, "unix", 0, &unix_seq_fops
)) {
2391 unix_sysctl_unregister(net
);
2400 static void __net_exit
unix_net_exit(struct net
*net
)
2402 unix_sysctl_unregister(net
);
2403 proc_net_remove(net
, "unix");
2406 static struct pernet_operations unix_net_ops
= {
2407 .init
= unix_net_init
,
2408 .exit
= unix_net_exit
,
2411 static int __init
af_unix_init(void)
2414 struct sk_buff
*dummy_skb
;
2416 BUILD_BUG_ON(sizeof(struct unix_skb_parms
) > sizeof(dummy_skb
->cb
));
2418 rc
= proto_register(&unix_proto
, 1);
2420 printk(KERN_CRIT
"%s: Cannot create unix_sock SLAB cache!\n",
2425 sock_register(&unix_family_ops
);
2426 register_pernet_subsys(&unix_net_ops
);
2431 static void __exit
af_unix_exit(void)
2433 sock_unregister(PF_UNIX
);
2434 proto_unregister(&unix_proto
);
2435 unregister_pernet_subsys(&unix_net_ops
);
2438 /* Earlier than device_initcall() so that other drivers invoking
2439 request_module() don't end up in a loop when modprobe tries
2440 to use a UNIX socket. But later than subsys_initcall() because
2441 we depend on stuff initialised there */
2442 fs_initcall(af_unix_init
);
2443 module_exit(af_unix_exit
);
2445 MODULE_LICENSE("GPL");
2446 MODULE_ALIAS_NETPROTO(PF_UNIX
);