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 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
119 static DEFINE_SPINLOCK(unix_table_lock);
120 static atomic_long_t unix_nr_socks;
122 #define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE])
124 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
126 #ifdef CONFIG_SECURITY_NETWORK
127 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
129 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
132 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
134 scm->secid = *UNIXSID(skb);
137 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
140 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142 #endif /* CONFIG_SECURITY_NETWORK */
145 * SMP locking strategy:
146 * hash table is protected with spinlock unix_table_lock
147 * each socket state is protected by separate spin lock.
150 static inline unsigned unix_hash_fold(__wsum n)
152 unsigned int hash = (__force unsigned int)csum_fold(n);
155 return hash&(UNIX_HASH_SIZE-1);
158 #define unix_peer(sk) (unix_sk(sk)->peer)
160 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
162 return unix_peer(osk) == sk;
165 static inline int unix_may_send(struct sock *sk, struct sock *osk)
167 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
170 static inline int unix_recvq_full(struct sock const *sk)
172 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
175 static struct sock *unix_peer_get(struct sock *s)
183 unix_state_unlock(s);
187 static inline void unix_release_addr(struct unix_address *addr)
189 if (atomic_dec_and_test(&addr->refcnt))
194 * Check unix socket name:
195 * - should be not zero length.
196 * - if started by not zero, should be NULL terminated (FS object)
197 * - if started by zero, it is abstract name.
200 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
202 if (len <= sizeof(short) || len > sizeof(*sunaddr))
204 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
206 if (sunaddr->sun_path[0]) {
208 * This may look like an off by one error but it is a bit more
209 * subtle. 108 is the longest valid AF_UNIX path for a binding.
210 * sun_path[108] doesn't as such exist. However in kernel space
211 * we are guaranteed that it is a valid memory location in our
212 * kernel address buffer.
214 ((char *)sunaddr)[len] = 0;
215 len = strlen(sunaddr->sun_path)+1+sizeof(short);
219 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
223 static void __unix_remove_socket(struct sock *sk)
225 sk_del_node_init(sk);
228 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
230 WARN_ON(!sk_unhashed(sk));
231 sk_add_node(sk, list);
234 static inline void unix_remove_socket(struct sock *sk)
236 spin_lock(&unix_table_lock);
237 __unix_remove_socket(sk);
238 spin_unlock(&unix_table_lock);
241 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
243 spin_lock(&unix_table_lock);
244 __unix_insert_socket(list, sk);
245 spin_unlock(&unix_table_lock);
248 static struct sock *__unix_find_socket_byname(struct net *net,
249 struct sockaddr_un *sunname,
250 int len, int type, unsigned hash)
253 struct hlist_node *node;
255 sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
256 struct unix_sock *u = unix_sk(s);
258 if (!net_eq(sock_net(s), net))
261 if (u->addr->len == len &&
262 !memcmp(u->addr->name, sunname, len))
270 static inline struct sock *unix_find_socket_byname(struct net *net,
271 struct sockaddr_un *sunname,
277 spin_lock(&unix_table_lock);
278 s = __unix_find_socket_byname(net, sunname, len, type, hash);
281 spin_unlock(&unix_table_lock);
285 static struct sock *unix_find_socket_byinode(struct inode *i)
288 struct hlist_node *node;
290 spin_lock(&unix_table_lock);
292 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
293 struct dentry *dentry = unix_sk(s)->dentry;
295 if (dentry && dentry->d_inode == i) {
302 spin_unlock(&unix_table_lock);
306 /* Support code for asymmetrically connected dgram sockets
308 * If a datagram socket is connected to a socket not itself connected
309 * to the first socket (eg, /dev/log), clients may only enqueue more
310 * messages if the present receive queue of the server socket is not
311 * "too large". This means there's a second writeability condition
312 * poll and sendmsg need to test. The dgram recv code will do a wake
313 * up on the peer_wait wait queue of a socket upon reception of a
314 * datagram which needs to be propagated to sleeping would-be writers
315 * since these might not have sent anything so far. This can't be
316 * accomplished via poll_wait because the lifetime of the server
317 * socket might be less than that of its clients if these break their
318 * association with it or if the server socket is closed while clients
319 * are still connected to it and there's no way to inform "a polling
320 * implementation" that it should let go of a certain wait queue
322 * In order to propagate a wake up, a wait_queue_t of the client
323 * socket is enqueued on the peer_wait queue of the server socket
324 * whose wake function does a wake_up on the ordinary client socket
325 * wait queue. This connection is established whenever a write (or
326 * poll for write) hit the flow control condition and broken when the
327 * association to the server socket is dissolved or after a wake up
331 static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
335 wait_queue_head_t *u_sleep;
337 u = container_of(q, struct unix_sock, peer_wake);
339 __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
341 u->peer_wake.private = NULL;
343 /* relaying can only happen while the wq still exists */
344 u_sleep = sk_sleep(&u->sk);
346 wake_up_interruptible_poll(u_sleep, key);
351 static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
353 struct unix_sock *u, *u_other;
357 u_other = unix_sk(other);
359 spin_lock(&u_other->peer_wait.lock);
361 if (!u->peer_wake.private) {
362 u->peer_wake.private = other;
363 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
368 spin_unlock(&u_other->peer_wait.lock);
372 static void unix_dgram_peer_wake_disconnect(struct sock *sk,
375 struct unix_sock *u, *u_other;
378 u_other = unix_sk(other);
379 spin_lock(&u_other->peer_wait.lock);
381 if (u->peer_wake.private == other) {
382 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
383 u->peer_wake.private = NULL;
386 spin_unlock(&u_other->peer_wait.lock);
389 static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
392 unix_dgram_peer_wake_disconnect(sk, other);
393 wake_up_interruptible_poll(sk_sleep(sk),
400 * - unix_peer(sk) == other
401 * - association is stable
403 static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
407 connected = unix_dgram_peer_wake_connect(sk, other);
409 if (unix_recvq_full(other))
413 unix_dgram_peer_wake_disconnect(sk, other);
418 static inline int unix_writable(struct sock *sk)
420 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
423 static void unix_write_space(struct sock *sk)
425 struct socket_wq *wq;
428 if (unix_writable(sk)) {
429 wq = rcu_dereference(sk->sk_wq);
430 if (wq_has_sleeper(wq))
431 wake_up_interruptible_sync_poll(&wq->wait,
432 POLLOUT | POLLWRNORM | POLLWRBAND);
433 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
438 /* When dgram socket disconnects (or changes its peer), we clear its receive
439 * queue of packets arrived from previous peer. First, it allows to do
440 * flow control based only on wmem_alloc; second, sk connected to peer
441 * may receive messages only from that peer. */
442 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
444 if (!skb_queue_empty(&sk->sk_receive_queue)) {
445 skb_queue_purge(&sk->sk_receive_queue);
446 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
448 /* If one link of bidirectional dgram pipe is disconnected,
449 * we signal error. Messages are lost. Do not make this,
450 * when peer was not connected to us.
452 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
453 other->sk_err = ECONNRESET;
454 other->sk_error_report(other);
459 static void unix_sock_destructor(struct sock *sk)
461 struct unix_sock *u = unix_sk(sk);
463 skb_queue_purge(&sk->sk_receive_queue);
465 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
466 WARN_ON(!sk_unhashed(sk));
467 WARN_ON(sk->sk_socket);
468 if (!sock_flag(sk, SOCK_DEAD)) {
469 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
474 unix_release_addr(u->addr);
476 atomic_long_dec(&unix_nr_socks);
478 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
480 #ifdef UNIX_REFCNT_DEBUG
481 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
482 atomic_long_read(&unix_nr_socks));
486 static void unix_release_sock(struct sock *sk, int embrion)
488 struct unix_sock *u = unix_sk(sk);
489 struct dentry *dentry;
490 struct vfsmount *mnt;
495 unix_remove_socket(sk);
500 sk->sk_shutdown = SHUTDOWN_MASK;
505 state = sk->sk_state;
506 sk->sk_state = TCP_CLOSE;
507 unix_state_unlock(sk);
509 wake_up_interruptible_all(&u->peer_wait);
511 skpair = unix_peer(sk);
513 if (skpair != NULL) {
514 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
515 unix_state_lock(skpair);
517 skpair->sk_shutdown = SHUTDOWN_MASK;
518 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
519 skpair->sk_err = ECONNRESET;
520 unix_state_unlock(skpair);
521 skpair->sk_state_change(skpair);
522 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
525 unix_dgram_peer_wake_disconnect(sk, skpair);
526 sock_put(skpair); /* It may now die */
527 unix_peer(sk) = NULL;
530 /* Try to flush out this socket. Throw out buffers at least */
532 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
533 if (state == TCP_LISTEN)
534 unix_release_sock(skb->sk, 1);
535 /* passed fds are erased in the kfree_skb hook */
546 /* ---- Socket is dead now and most probably destroyed ---- */
549 * Fixme: BSD difference: In BSD all sockets connected to use get
550 * ECONNRESET and we die on the spot. In Linux we behave
551 * like files and pipes do and wait for the last
554 * Can't we simply set sock->err?
556 * What the above comment does talk about? --ANK(980817)
559 if (unix_tot_inflight)
560 unix_gc(); /* Garbage collect fds */
563 static void init_peercred(struct sock *sk)
565 put_pid(sk->sk_peer_pid);
566 if (sk->sk_peer_cred)
567 put_cred(sk->sk_peer_cred);
568 sk->sk_peer_pid = get_pid(task_tgid(current));
569 sk->sk_peer_cred = get_current_cred();
572 static void copy_peercred(struct sock *sk, struct sock *peersk)
574 put_pid(sk->sk_peer_pid);
575 if (sk->sk_peer_cred)
576 put_cred(sk->sk_peer_cred);
577 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
578 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
581 static int unix_listen(struct socket *sock, int backlog)
584 struct sock *sk = sock->sk;
585 struct unix_sock *u = unix_sk(sk);
586 struct pid *old_pid = NULL;
587 const struct cred *old_cred = NULL;
590 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
591 goto out; /* Only stream/seqpacket sockets accept */
594 goto out; /* No listens on an unbound socket */
596 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
598 if (backlog > sk->sk_max_ack_backlog)
599 wake_up_interruptible_all(&u->peer_wait);
600 sk->sk_max_ack_backlog = backlog;
601 sk->sk_state = TCP_LISTEN;
602 /* set credentials so connect can copy them */
607 unix_state_unlock(sk);
615 static int unix_release(struct socket *);
616 static int unix_bind(struct socket *, struct sockaddr *, int);
617 static int unix_stream_connect(struct socket *, struct sockaddr *,
618 int addr_len, int flags);
619 static int unix_socketpair(struct socket *, struct socket *);
620 static int unix_accept(struct socket *, struct socket *, int);
621 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
622 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
623 static unsigned int unix_dgram_poll(struct file *, struct socket *,
625 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
626 static int unix_shutdown(struct socket *, int);
627 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
628 struct msghdr *, size_t);
629 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
630 struct msghdr *, size_t, int);
631 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
632 struct msghdr *, size_t);
633 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
634 struct msghdr *, size_t, int);
635 static int unix_dgram_connect(struct socket *, struct sockaddr *,
637 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
638 struct msghdr *, size_t);
639 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
640 struct msghdr *, size_t, int);
642 static const struct proto_ops unix_stream_ops = {
644 .owner = THIS_MODULE,
645 .release = unix_release,
647 .connect = unix_stream_connect,
648 .socketpair = unix_socketpair,
649 .accept = unix_accept,
650 .getname = unix_getname,
653 .listen = unix_listen,
654 .shutdown = unix_shutdown,
655 .setsockopt = sock_no_setsockopt,
656 .getsockopt = sock_no_getsockopt,
657 .sendmsg = unix_stream_sendmsg,
658 .recvmsg = unix_stream_recvmsg,
659 .mmap = sock_no_mmap,
660 .sendpage = sock_no_sendpage,
663 static const struct proto_ops unix_dgram_ops = {
665 .owner = THIS_MODULE,
666 .release = unix_release,
668 .connect = unix_dgram_connect,
669 .socketpair = unix_socketpair,
670 .accept = sock_no_accept,
671 .getname = unix_getname,
672 .poll = unix_dgram_poll,
674 .listen = sock_no_listen,
675 .shutdown = unix_shutdown,
676 .setsockopt = sock_no_setsockopt,
677 .getsockopt = sock_no_getsockopt,
678 .sendmsg = unix_dgram_sendmsg,
679 .recvmsg = unix_dgram_recvmsg,
680 .mmap = sock_no_mmap,
681 .sendpage = sock_no_sendpage,
684 static const struct proto_ops unix_seqpacket_ops = {
686 .owner = THIS_MODULE,
687 .release = unix_release,
689 .connect = unix_stream_connect,
690 .socketpair = unix_socketpair,
691 .accept = unix_accept,
692 .getname = unix_getname,
693 .poll = unix_dgram_poll,
695 .listen = unix_listen,
696 .shutdown = unix_shutdown,
697 .setsockopt = sock_no_setsockopt,
698 .getsockopt = sock_no_getsockopt,
699 .sendmsg = unix_seqpacket_sendmsg,
700 .recvmsg = unix_seqpacket_recvmsg,
701 .mmap = sock_no_mmap,
702 .sendpage = sock_no_sendpage,
705 static struct proto unix_proto = {
707 .owner = THIS_MODULE,
708 .obj_size = sizeof(struct unix_sock),
712 * AF_UNIX sockets do not interact with hardware, hence they
713 * dont trigger interrupts - so it's safe for them to have
714 * bh-unsafe locking for their sk_receive_queue.lock. Split off
715 * this special lock-class by reinitializing the spinlock key:
717 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
719 static struct sock *unix_create1(struct net *net, struct socket *sock)
721 struct sock *sk = NULL;
724 atomic_long_inc(&unix_nr_socks);
725 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
728 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
732 sock_init_data(sock, sk);
733 lockdep_set_class(&sk->sk_receive_queue.lock,
734 &af_unix_sk_receive_queue_lock_key);
736 sk->sk_write_space = unix_write_space;
737 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
738 sk->sk_destruct = unix_sock_destructor;
742 spin_lock_init(&u->lock);
743 atomic_long_set(&u->inflight, 0);
744 INIT_LIST_HEAD(&u->link);
745 mutex_init(&u->readlock); /* single task reading lock */
746 init_waitqueue_head(&u->peer_wait);
747 init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
748 unix_insert_socket(unix_sockets_unbound, sk);
751 atomic_long_dec(&unix_nr_socks);
754 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
760 static int unix_create(struct net *net, struct socket *sock, int protocol,
763 if (protocol && protocol != PF_UNIX)
764 return -EPROTONOSUPPORT;
766 sock->state = SS_UNCONNECTED;
768 switch (sock->type) {
770 sock->ops = &unix_stream_ops;
773 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
777 sock->type = SOCK_DGRAM;
779 sock->ops = &unix_dgram_ops;
782 sock->ops = &unix_seqpacket_ops;
785 return -ESOCKTNOSUPPORT;
788 return unix_create1(net, sock) ? 0 : -ENOMEM;
791 static int unix_release(struct socket *sock)
793 struct sock *sk = sock->sk;
798 unix_release_sock(sk, 0);
804 static int unix_autobind(struct socket *sock)
806 struct sock *sk = sock->sk;
807 struct net *net = sock_net(sk);
808 struct unix_sock *u = unix_sk(sk);
809 static u32 ordernum = 1;
810 struct unix_address *addr;
812 unsigned int retries = 0;
814 err = mutex_lock_interruptible(&u->readlock);
823 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
827 addr->name->sun_family = AF_UNIX;
828 atomic_set(&addr->refcnt, 1);
831 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
832 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
834 spin_lock(&unix_table_lock);
835 ordernum = (ordernum+1)&0xFFFFF;
837 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
839 spin_unlock(&unix_table_lock);
841 * __unix_find_socket_byname() may take long time if many names
842 * are already in use.
845 /* Give up if all names seems to be in use. */
846 if (retries++ == 0xFFFFF) {
853 addr->hash ^= sk->sk_type;
855 __unix_remove_socket(sk);
857 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
858 spin_unlock(&unix_table_lock);
861 out: mutex_unlock(&u->readlock);
865 static struct sock *unix_find_other(struct net *net,
866 struct sockaddr_un *sunname, int len,
867 int type, unsigned hash, int *error)
873 if (sunname->sun_path[0]) {
875 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
878 inode = path.dentry->d_inode;
879 err = inode_permission(inode, MAY_WRITE);
884 if (!S_ISSOCK(inode->i_mode))
886 u = unix_find_socket_byinode(inode);
890 if (u->sk_type == type)
891 touch_atime(path.mnt, path.dentry);
896 if (u->sk_type != type) {
902 u = unix_find_socket_byname(net, sunname, len, type, hash);
904 struct dentry *dentry;
905 dentry = unix_sk(u)->dentry;
907 touch_atime(unix_sk(u)->mnt, dentry);
921 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
923 struct sock *sk = sock->sk;
924 struct net *net = sock_net(sk);
925 struct unix_sock *u = unix_sk(sk);
926 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
927 char *sun_path = sunaddr->sun_path;
928 struct dentry *dentry = NULL;
932 struct unix_address *addr;
933 struct hlist_head *list;
936 if (sunaddr->sun_family != AF_UNIX)
939 if (addr_len == sizeof(short)) {
940 err = unix_autobind(sock);
944 err = unix_mkname(sunaddr, addr_len, &hash);
949 err = mutex_lock_interruptible(&u->readlock);
958 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
962 memcpy(addr->name, sunaddr, addr_len);
963 addr->len = addr_len;
964 addr->hash = hash ^ sk->sk_type;
965 atomic_set(&addr->refcnt, 1);
971 * Get the parent directory, calculate the hash for last
974 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
975 err = PTR_ERR(dentry);
977 goto out_mknod_parent;
980 * All right, let's create it.
983 (SOCK_INODE(sock)->i_mode & ~current_umask());
984 err = mnt_want_write(path.mnt);
987 err = security_path_mknod(&path, dentry, mode, 0);
989 goto out_mknod_drop_write;
990 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
991 out_mknod_drop_write:
992 mnt_drop_write(path.mnt);
995 mutex_unlock(&path.dentry->d_inode->i_mutex);
997 path.dentry = dentry;
999 addr->hash = UNIX_HASH_SIZE;
1002 spin_lock(&unix_table_lock);
1006 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1007 sk->sk_type, hash)) {
1008 unix_release_addr(addr);
1012 list = &unix_socket_table[addr->hash];
1014 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
1015 u->dentry = path.dentry;
1020 __unix_remove_socket(sk);
1022 __unix_insert_socket(list, sk);
1025 spin_unlock(&unix_table_lock);
1027 mutex_unlock(&u->readlock);
1033 mutex_unlock(&path.dentry->d_inode->i_mutex);
1038 unix_release_addr(addr);
1042 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1044 if (unlikely(sk1 == sk2) || !sk2) {
1045 unix_state_lock(sk1);
1049 unix_state_lock(sk1);
1050 unix_state_lock_nested(sk2);
1052 unix_state_lock(sk2);
1053 unix_state_lock_nested(sk1);
1057 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1059 if (unlikely(sk1 == sk2) || !sk2) {
1060 unix_state_unlock(sk1);
1063 unix_state_unlock(sk1);
1064 unix_state_unlock(sk2);
1067 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1068 int alen, int flags)
1070 struct sock *sk = sock->sk;
1071 struct net *net = sock_net(sk);
1072 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1077 if (addr->sa_family != AF_UNSPEC) {
1078 err = unix_mkname(sunaddr, alen, &hash);
1083 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1084 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1088 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1092 unix_state_double_lock(sk, other);
1094 /* Apparently VFS overslept socket death. Retry. */
1095 if (sock_flag(other, SOCK_DEAD)) {
1096 unix_state_double_unlock(sk, other);
1102 if (!unix_may_send(sk, other))
1105 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1111 * 1003.1g breaking connected state with AF_UNSPEC
1114 unix_state_double_lock(sk, other);
1118 * If it was connected, reconnect.
1120 if (unix_peer(sk)) {
1121 struct sock *old_peer = unix_peer(sk);
1122 unix_peer(sk) = other;
1123 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1125 unix_state_double_unlock(sk, other);
1127 if (other != old_peer)
1128 unix_dgram_disconnected(sk, old_peer);
1131 unix_peer(sk) = other;
1132 unix_state_double_unlock(sk, other);
1137 unix_state_double_unlock(sk, other);
1143 static long unix_wait_for_peer(struct sock *other, long timeo)
1145 struct unix_sock *u = unix_sk(other);
1149 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1151 sched = !sock_flag(other, SOCK_DEAD) &&
1152 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1153 unix_recvq_full(other);
1155 unix_state_unlock(other);
1158 timeo = schedule_timeout(timeo);
1160 finish_wait(&u->peer_wait, &wait);
1164 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1165 int addr_len, int flags)
1167 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1168 struct sock *sk = sock->sk;
1169 struct net *net = sock_net(sk);
1170 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1171 struct sock *newsk = NULL;
1172 struct sock *other = NULL;
1173 struct sk_buff *skb = NULL;
1179 err = unix_mkname(sunaddr, addr_len, &hash);
1184 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1185 (err = unix_autobind(sock)) != 0)
1188 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1190 /* First of all allocate resources.
1191 If we will make it after state is locked,
1192 we will have to recheck all again in any case.
1197 /* create new sock for complete connection */
1198 newsk = unix_create1(sock_net(sk), NULL);
1202 /* Allocate skb for sending to listening sock */
1203 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1208 /* Find listening sock. */
1209 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1213 /* Latch state of peer */
1214 unix_state_lock(other);
1216 /* Apparently VFS overslept socket death. Retry. */
1217 if (sock_flag(other, SOCK_DEAD)) {
1218 unix_state_unlock(other);
1223 err = -ECONNREFUSED;
1224 if (other->sk_state != TCP_LISTEN)
1226 if (other->sk_shutdown & RCV_SHUTDOWN)
1229 if (unix_recvq_full(other)) {
1234 timeo = unix_wait_for_peer(other, timeo);
1236 err = sock_intr_errno(timeo);
1237 if (signal_pending(current))
1245 It is tricky place. We need to grab our state lock and cannot
1246 drop lock on peer. It is dangerous because deadlock is
1247 possible. Connect to self case and simultaneous
1248 attempt to connect are eliminated by checking socket
1249 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1250 check this before attempt to grab lock.
1252 Well, and we have to recheck the state after socket locked.
1258 /* This is ok... continue with connect */
1260 case TCP_ESTABLISHED:
1261 /* Socket is already connected */
1269 unix_state_lock_nested(sk);
1271 if (sk->sk_state != st) {
1272 unix_state_unlock(sk);
1273 unix_state_unlock(other);
1278 err = security_unix_stream_connect(sk, other, newsk);
1280 unix_state_unlock(sk);
1284 /* The way is open! Fastly set all the necessary fields... */
1287 unix_peer(newsk) = sk;
1288 newsk->sk_state = TCP_ESTABLISHED;
1289 newsk->sk_type = sk->sk_type;
1290 init_peercred(newsk);
1291 newu = unix_sk(newsk);
1292 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1293 otheru = unix_sk(other);
1295 /* copy address information from listening to new sock*/
1297 atomic_inc(&otheru->addr->refcnt);
1298 newu->addr = otheru->addr;
1300 if (otheru->dentry) {
1301 newu->dentry = dget(otheru->dentry);
1302 newu->mnt = mntget(otheru->mnt);
1305 /* Set credentials */
1306 copy_peercred(sk, other);
1308 sock->state = SS_CONNECTED;
1309 sk->sk_state = TCP_ESTABLISHED;
1312 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1313 unix_peer(sk) = newsk;
1315 unix_state_unlock(sk);
1317 /* take ten and and send info to listening sock */
1318 spin_lock(&other->sk_receive_queue.lock);
1319 __skb_queue_tail(&other->sk_receive_queue, skb);
1320 spin_unlock(&other->sk_receive_queue.lock);
1321 unix_state_unlock(other);
1322 other->sk_data_ready(other, 0);
1328 unix_state_unlock(other);
1333 unix_release_sock(newsk, 0);
1339 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1341 struct sock *ska = socka->sk, *skb = sockb->sk;
1343 /* Join our sockets back to back */
1346 unix_peer(ska) = skb;
1347 unix_peer(skb) = ska;
1351 if (ska->sk_type != SOCK_DGRAM) {
1352 ska->sk_state = TCP_ESTABLISHED;
1353 skb->sk_state = TCP_ESTABLISHED;
1354 socka->state = SS_CONNECTED;
1355 sockb->state = SS_CONNECTED;
1360 static void unix_sock_inherit_flags(const struct socket *old,
1363 if (test_bit(SOCK_PASSCRED, &old->flags))
1364 set_bit(SOCK_PASSCRED, &new->flags);
1365 if (test_bit(SOCK_PASSSEC, &old->flags))
1366 set_bit(SOCK_PASSSEC, &new->flags);
1369 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1371 struct sock *sk = sock->sk;
1373 struct sk_buff *skb;
1377 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1381 if (sk->sk_state != TCP_LISTEN)
1384 /* If socket state is TCP_LISTEN it cannot change (for now...),
1385 * so that no locks are necessary.
1388 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1390 /* This means receive shutdown. */
1397 skb_free_datagram(sk, skb);
1398 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1400 /* attach accepted sock to socket */
1401 unix_state_lock(tsk);
1402 newsock->state = SS_CONNECTED;
1403 unix_sock_inherit_flags(sock, newsock);
1404 sock_graft(tsk, newsock);
1405 unix_state_unlock(tsk);
1413 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1415 struct sock *sk = sock->sk;
1416 struct unix_sock *u;
1417 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1421 sk = unix_peer_get(sk);
1432 unix_state_lock(sk);
1434 sunaddr->sun_family = AF_UNIX;
1435 sunaddr->sun_path[0] = 0;
1436 *uaddr_len = sizeof(short);
1438 struct unix_address *addr = u->addr;
1440 *uaddr_len = addr->len;
1441 memcpy(sunaddr, addr->name, *uaddr_len);
1443 unix_state_unlock(sk);
1449 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1453 scm->fp = UNIXCB(skb).fp;
1454 UNIXCB(skb).fp = NULL;
1456 for (i = scm->fp->count-1; i >= 0; i--)
1457 unix_notinflight(scm->fp->user, scm->fp->fp[i]);
1460 static void unix_destruct_scm(struct sk_buff *skb)
1462 struct scm_cookie scm;
1463 memset(&scm, 0, sizeof(scm));
1464 scm.pid = UNIXCB(skb).pid;
1465 scm.cred = UNIXCB(skb).cred;
1467 unix_detach_fds(&scm, skb);
1469 /* Alas, it calls VFS */
1470 /* So fscking what? fput() had been SMP-safe since the last Summer */
1476 * The "user->unix_inflight" variable is protected by the garbage
1477 * collection lock, and we just read it locklessly here. If you go
1478 * over the limit, there might be a tiny race in actually noticing
1479 * it across threads. Tough.
1481 static inline bool too_many_unix_fds(struct task_struct *p)
1483 struct user_struct *user = current_user();
1485 if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1486 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1490 #define MAX_RECURSION_LEVEL 4
1492 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1495 unsigned char max_level = 0;
1496 int unix_sock_count = 0;
1498 if (too_many_unix_fds(current))
1499 return -ETOOMANYREFS;
1501 for (i = scm->fp->count - 1; i >= 0; i--) {
1502 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1506 max_level = max(max_level,
1507 unix_sk(sk)->recursion_level);
1510 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1511 return -ETOOMANYREFS;
1514 * Need to duplicate file references for the sake of garbage
1515 * collection. Otherwise a socket in the fps might become a
1516 * candidate for GC while the skb is not yet queued.
1518 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1519 if (!UNIXCB(skb).fp)
1522 for (i = scm->fp->count - 1; i >= 0; i--)
1523 unix_inflight(scm->fp->user, scm->fp->fp[i]);
1527 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1531 UNIXCB(skb).pid = get_pid(scm->pid);
1533 UNIXCB(skb).cred = get_cred(scm->cred);
1534 UNIXCB(skb).fp = NULL;
1535 if (scm->fp && send_fds)
1536 err = unix_attach_fds(scm, skb);
1538 skb->destructor = unix_destruct_scm;
1543 * Some apps rely on write() giving SCM_CREDENTIALS
1544 * We include credentials if source or destination socket
1545 * asserted SOCK_PASSCRED.
1547 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1548 const struct sock *other)
1550 if (UNIXCB(skb).cred)
1552 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1553 !other->sk_socket ||
1554 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1555 UNIXCB(skb).pid = get_pid(task_tgid(current));
1556 UNIXCB(skb).cred = get_current_cred();
1561 * Send AF_UNIX data.
1564 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1565 struct msghdr *msg, size_t len)
1567 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1568 struct sock *sk = sock->sk;
1569 struct net *net = sock_net(sk);
1570 struct unix_sock *u = unix_sk(sk);
1571 struct sockaddr_un *sunaddr = msg->msg_name;
1572 struct sock *other = NULL;
1573 int namelen = 0; /* fake GCC */
1576 struct sk_buff *skb;
1578 struct scm_cookie tmp_scm;
1582 if (NULL == siocb->scm)
1583 siocb->scm = &tmp_scm;
1585 err = scm_send(sock, msg, siocb->scm, false);
1590 if (msg->msg_flags&MSG_OOB)
1593 if (msg->msg_namelen) {
1594 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1601 other = unix_peer_get(sk);
1606 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1607 && (err = unix_autobind(sock)) != 0)
1611 if (len > sk->sk_sndbuf - 32)
1614 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1618 err = unix_scm_to_skb(siocb->scm, skb, true);
1621 max_level = err + 1;
1622 unix_get_secdata(siocb->scm, skb);
1624 skb_reset_transport_header(skb);
1625 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1629 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1634 if (sunaddr == NULL)
1637 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1643 if (sk_filter(other, skb) < 0) {
1644 /* Toss the packet but do not return any error to the sender */
1650 unix_state_lock(other);
1653 if (!unix_may_send(sk, other))
1656 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1658 * Check with 1003.1g - what should
1661 unix_state_unlock(other);
1665 unix_state_lock(sk);
1668 if (unix_peer(sk) == other) {
1669 unix_peer(sk) = NULL;
1670 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1672 unix_state_unlock(sk);
1674 unix_dgram_disconnected(sk, other);
1676 err = -ECONNREFUSED;
1678 unix_state_unlock(sk);
1688 if (other->sk_shutdown & RCV_SHUTDOWN)
1691 if (sk->sk_type != SOCK_SEQPACKET) {
1692 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1697 if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1699 timeo = unix_wait_for_peer(other, timeo);
1701 err = sock_intr_errno(timeo);
1702 if (signal_pending(current))
1709 unix_state_unlock(other);
1710 unix_state_double_lock(sk, other);
1713 if (unix_peer(sk) != other ||
1714 unix_dgram_peer_wake_me(sk, other)) {
1722 goto restart_locked;
1726 if (unlikely(sk_locked))
1727 unix_state_unlock(sk);
1729 if (sock_flag(other, SOCK_RCVTSTAMP))
1730 __net_timestamp(skb);
1731 maybe_add_creds(skb, sock, other);
1732 skb_queue_tail(&other->sk_receive_queue, skb);
1733 if (max_level > unix_sk(other)->recursion_level)
1734 unix_sk(other)->recursion_level = max_level;
1735 unix_state_unlock(other);
1736 other->sk_data_ready(other, len);
1738 scm_destroy(siocb->scm);
1743 unix_state_unlock(sk);
1744 unix_state_unlock(other);
1750 scm_destroy(siocb->scm);
1755 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1756 struct msghdr *msg, size_t len)
1758 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1759 struct sock *sk = sock->sk;
1760 struct sock *other = NULL;
1762 struct sk_buff *skb;
1764 struct scm_cookie tmp_scm;
1765 bool fds_sent = false;
1768 if (NULL == siocb->scm)
1769 siocb->scm = &tmp_scm;
1771 err = scm_send(sock, msg, siocb->scm, false);
1776 if (msg->msg_flags&MSG_OOB)
1779 if (msg->msg_namelen) {
1780 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1784 other = unix_peer(sk);
1789 if (sk->sk_shutdown & SEND_SHUTDOWN)
1792 while (sent < len) {
1794 * Optimisation for the fact that under 0.01% of X
1795 * messages typically need breaking up.
1800 /* Keep two messages in the pipe so it schedules better */
1801 if (size > ((sk->sk_sndbuf >> 1) - 64))
1802 size = (sk->sk_sndbuf >> 1) - 64;
1804 if (size > SKB_MAX_ALLOC)
1805 size = SKB_MAX_ALLOC;
1811 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1818 * If you pass two values to the sock_alloc_send_skb
1819 * it tries to grab the large buffer with GFP_NOFS
1820 * (which can fail easily), and if it fails grab the
1821 * fallback size buffer which is under a page and will
1824 size = min_t(int, size, skb_tailroom(skb));
1827 /* Only send the fds in the first buffer */
1828 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1833 max_level = err + 1;
1836 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1842 unix_state_lock(other);
1844 if (sock_flag(other, SOCK_DEAD) ||
1845 (other->sk_shutdown & RCV_SHUTDOWN))
1848 maybe_add_creds(skb, sock, other);
1849 skb_queue_tail(&other->sk_receive_queue, skb);
1850 if (max_level > unix_sk(other)->recursion_level)
1851 unix_sk(other)->recursion_level = max_level;
1852 unix_state_unlock(other);
1853 other->sk_data_ready(other, size);
1857 scm_destroy(siocb->scm);
1863 unix_state_unlock(other);
1866 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1867 send_sig(SIGPIPE, current, 0);
1870 scm_destroy(siocb->scm);
1872 return sent ? : err;
1875 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1876 struct msghdr *msg, size_t len)
1879 struct sock *sk = sock->sk;
1881 err = sock_error(sk);
1885 if (sk->sk_state != TCP_ESTABLISHED)
1888 if (msg->msg_namelen)
1889 msg->msg_namelen = 0;
1891 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1894 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1895 struct msghdr *msg, size_t size,
1898 struct sock *sk = sock->sk;
1900 if (sk->sk_state != TCP_ESTABLISHED)
1903 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1906 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1908 struct unix_sock *u = unix_sk(sk);
1911 msg->msg_namelen = u->addr->len;
1912 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1916 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1917 struct msghdr *msg, size_t size,
1920 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1921 struct scm_cookie tmp_scm;
1922 struct sock *sk = sock->sk;
1923 struct unix_sock *u = unix_sk(sk);
1924 int noblock = flags & MSG_DONTWAIT;
1925 struct sk_buff *skb;
1932 err = mutex_lock_interruptible(&u->readlock);
1933 if (unlikely(err)) {
1934 /* recvmsg() in non blocking mode is supposed to return -EAGAIN
1935 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
1937 err = noblock ? -EAGAIN : -ERESTARTSYS;
1941 skb = skb_recv_datagram(sk, flags, noblock, &err);
1943 unix_state_lock(sk);
1944 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1945 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1946 (sk->sk_shutdown & RCV_SHUTDOWN))
1948 unix_state_unlock(sk);
1952 wake_up_interruptible_sync_poll(&u->peer_wait,
1953 POLLOUT | POLLWRNORM | POLLWRBAND);
1956 unix_copy_addr(msg, skb->sk);
1958 if (size > skb->len)
1960 else if (size < skb->len)
1961 msg->msg_flags |= MSG_TRUNC;
1963 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1967 if (sock_flag(sk, SOCK_RCVTSTAMP))
1968 __sock_recv_timestamp(msg, sk, skb);
1971 siocb->scm = &tmp_scm;
1972 memset(&tmp_scm, 0, sizeof(tmp_scm));
1974 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1975 unix_set_secdata(siocb->scm, skb);
1977 if (!(flags & MSG_PEEK)) {
1979 unix_detach_fds(siocb->scm, skb);
1981 /* It is questionable: on PEEK we could:
1982 - do not return fds - good, but too simple 8)
1983 - return fds, and do not return them on read (old strategy,
1985 - clone fds (I chose it for now, it is the most universal
1988 POSIX 1003.1g does not actually define this clearly
1989 at all. POSIX 1003.1g doesn't define a lot of things
1994 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1998 scm_recv(sock, msg, siocb->scm, flags);
2001 skb_free_datagram(sk, skb);
2003 mutex_unlock(&u->readlock);
2009 * Sleep until data has arrive. But check for races..
2012 static long unix_stream_data_wait(struct sock *sk, long timeo)
2016 unix_state_lock(sk);
2019 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2021 if (!skb_queue_empty(&sk->sk_receive_queue) ||
2023 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2024 signal_pending(current) ||
2028 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
2029 unix_state_unlock(sk);
2030 timeo = schedule_timeout(timeo);
2031 unix_state_lock(sk);
2033 if (sock_flag(sk, SOCK_DEAD))
2036 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
2039 finish_wait(sk_sleep(sk), &wait);
2040 unix_state_unlock(sk);
2046 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
2047 struct msghdr *msg, size_t size,
2050 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
2051 struct scm_cookie tmp_scm;
2052 struct sock *sk = sock->sk;
2053 struct unix_sock *u = unix_sk(sk);
2054 struct sockaddr_un *sunaddr = msg->msg_name;
2056 int noblock = flags & MSG_DONTWAIT;
2057 int check_creds = 0;
2063 if (sk->sk_state != TCP_ESTABLISHED)
2070 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
2071 timeo = sock_rcvtimeo(sk, noblock);
2073 /* Lock the socket to prevent queue disordering
2074 * while sleeps in memcpy_tomsg
2078 siocb->scm = &tmp_scm;
2079 memset(&tmp_scm, 0, sizeof(tmp_scm));
2082 mutex_lock(&u->readlock);
2086 struct sk_buff *skb;
2088 unix_state_lock(sk);
2089 if (sock_flag(sk, SOCK_DEAD)) {
2093 skb = skb_peek(&sk->sk_receive_queue);
2095 unix_sk(sk)->recursion_level = 0;
2096 if (copied >= target)
2100 * POSIX 1003.1g mandates this order.
2103 err = sock_error(sk);
2106 if (sk->sk_shutdown & RCV_SHUTDOWN)
2109 unix_state_unlock(sk);
2113 mutex_unlock(&u->readlock);
2115 timeo = unix_stream_data_wait(sk, timeo);
2117 if (signal_pending(current)) {
2118 err = sock_intr_errno(timeo);
2119 scm_destroy(siocb->scm);
2123 mutex_lock(&u->readlock);
2126 unix_state_unlock(sk);
2129 unix_state_unlock(sk);
2132 /* Never glue messages from different writers */
2133 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
2134 (UNIXCB(skb).cred != siocb->scm->cred))
2136 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2137 /* Copy credentials */
2138 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
2142 /* Copy address just once */
2144 unix_copy_addr(msg, skb->sk);
2148 chunk = min_t(unsigned int, skb->len, size);
2149 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
2157 /* Mark read part of skb as used */
2158 if (!(flags & MSG_PEEK)) {
2159 skb_pull(skb, chunk);
2162 unix_detach_fds(siocb->scm, skb);
2167 skb_unlink(skb, &sk->sk_receive_queue);
2173 /* It is questionable, see note in unix_dgram_recvmsg.
2176 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
2182 mutex_unlock(&u->readlock);
2183 scm_recv(sock, msg, siocb->scm, flags);
2185 return copied ? : err;
2188 static int unix_shutdown(struct socket *sock, int mode)
2190 struct sock *sk = sock->sk;
2193 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2198 unix_state_lock(sk);
2199 sk->sk_shutdown |= mode;
2200 other = unix_peer(sk);
2203 unix_state_unlock(sk);
2204 sk->sk_state_change(sk);
2207 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2211 if (mode&RCV_SHUTDOWN)
2212 peer_mode |= SEND_SHUTDOWN;
2213 if (mode&SEND_SHUTDOWN)
2214 peer_mode |= RCV_SHUTDOWN;
2215 unix_state_lock(other);
2216 other->sk_shutdown |= peer_mode;
2217 unix_state_unlock(other);
2218 other->sk_state_change(other);
2219 if (peer_mode == SHUTDOWN_MASK)
2220 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2221 else if (peer_mode & RCV_SHUTDOWN)
2222 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2230 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2232 struct sock *sk = sock->sk;
2238 amount = sk_wmem_alloc_get(sk);
2239 err = put_user(amount, (int __user *)arg);
2243 struct sk_buff *skb;
2245 if (sk->sk_state == TCP_LISTEN) {
2250 spin_lock(&sk->sk_receive_queue.lock);
2251 if (sk->sk_type == SOCK_STREAM ||
2252 sk->sk_type == SOCK_SEQPACKET) {
2253 skb_queue_walk(&sk->sk_receive_queue, skb)
2256 skb = skb_peek(&sk->sk_receive_queue);
2260 spin_unlock(&sk->sk_receive_queue.lock);
2261 err = put_user(amount, (int __user *)arg);
2272 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2274 struct sock *sk = sock->sk;
2277 sock_poll_wait(file, sk_sleep(sk), wait);
2280 /* exceptional events? */
2283 if (sk->sk_shutdown == SHUTDOWN_MASK)
2285 if (sk->sk_shutdown & RCV_SHUTDOWN)
2286 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2289 if (!skb_queue_empty(&sk->sk_receive_queue))
2290 mask |= POLLIN | POLLRDNORM;
2292 /* Connection-based need to check for termination and startup */
2293 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2294 sk->sk_state == TCP_CLOSE)
2298 * we set writable also when the other side has shut down the
2299 * connection. This prevents stuck sockets.
2301 if (unix_writable(sk))
2302 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2307 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2310 struct sock *sk = sock->sk, *other;
2311 unsigned int mask, writable;
2313 sock_poll_wait(file, sk_sleep(sk), wait);
2316 /* exceptional events? */
2317 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2319 if (sk->sk_shutdown & RCV_SHUTDOWN)
2320 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2321 if (sk->sk_shutdown == SHUTDOWN_MASK)
2325 if (!skb_queue_empty(&sk->sk_receive_queue))
2326 mask |= POLLIN | POLLRDNORM;
2328 /* Connection-based need to check for termination and startup */
2329 if (sk->sk_type == SOCK_SEQPACKET) {
2330 if (sk->sk_state == TCP_CLOSE)
2332 /* connection hasn't started yet? */
2333 if (sk->sk_state == TCP_SYN_SENT)
2337 /* No write status requested, avoid expensive OUT tests. */
2338 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2341 writable = unix_writable(sk);
2343 unix_state_lock(sk);
2345 other = unix_peer(sk);
2346 if (other && unix_peer(other) != sk &&
2347 unix_recvq_full(other) &&
2348 unix_dgram_peer_wake_me(sk, other))
2351 unix_state_unlock(sk);
2355 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2357 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2362 #ifdef CONFIG_PROC_FS
2363 static struct sock *first_unix_socket(int *i)
2365 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2366 if (!hlist_empty(&unix_socket_table[*i]))
2367 return __sk_head(&unix_socket_table[*i]);
2372 static struct sock *next_unix_socket(int *i, struct sock *s)
2374 struct sock *next = sk_next(s);
2375 /* More in this chain? */
2378 /* Look for next non-empty chain. */
2379 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2380 if (!hlist_empty(&unix_socket_table[*i]))
2381 return __sk_head(&unix_socket_table[*i]);
2386 struct unix_iter_state {
2387 struct seq_net_private p;
2391 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2393 struct unix_iter_state *iter = seq->private;
2397 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2398 if (sock_net(s) != seq_file_net(seq))
2407 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2408 __acquires(unix_table_lock)
2410 spin_lock(&unix_table_lock);
2411 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2414 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2416 struct unix_iter_state *iter = seq->private;
2417 struct sock *sk = v;
2420 if (v == SEQ_START_TOKEN)
2421 sk = first_unix_socket(&iter->i);
2423 sk = next_unix_socket(&iter->i, sk);
2424 while (sk && (sock_net(sk) != seq_file_net(seq)))
2425 sk = next_unix_socket(&iter->i, sk);
2429 static void unix_seq_stop(struct seq_file *seq, void *v)
2430 __releases(unix_table_lock)
2432 spin_unlock(&unix_table_lock);
2435 static int unix_seq_show(struct seq_file *seq, void *v)
2438 if (v == SEQ_START_TOKEN)
2439 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2443 struct unix_sock *u = unix_sk(s);
2446 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2448 atomic_read(&s->sk_refcnt),
2450 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2453 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2454 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2462 len = u->addr->len - sizeof(short);
2463 if (!UNIX_ABSTRACT(s))
2469 for ( ; i < len; i++)
2470 seq_putc(seq, u->addr->name->sun_path[i]);
2472 unix_state_unlock(s);
2473 seq_putc(seq, '\n');
2479 static const struct seq_operations unix_seq_ops = {
2480 .start = unix_seq_start,
2481 .next = unix_seq_next,
2482 .stop = unix_seq_stop,
2483 .show = unix_seq_show,
2486 static int unix_seq_open(struct inode *inode, struct file *file)
2488 return seq_open_net(inode, file, &unix_seq_ops,
2489 sizeof(struct unix_iter_state));
2492 static const struct file_operations unix_seq_fops = {
2493 .owner = THIS_MODULE,
2494 .open = unix_seq_open,
2496 .llseek = seq_lseek,
2497 .release = seq_release_net,
2502 static const struct net_proto_family unix_family_ops = {
2504 .create = unix_create,
2505 .owner = THIS_MODULE,
2509 static int __net_init unix_net_init(struct net *net)
2511 int error = -ENOMEM;
2513 net->unx.sysctl_max_dgram_qlen = 10;
2514 if (unix_sysctl_register(net))
2517 #ifdef CONFIG_PROC_FS
2518 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2519 unix_sysctl_unregister(net);
2528 static void __net_exit unix_net_exit(struct net *net)
2530 unix_sysctl_unregister(net);
2531 proc_net_remove(net, "unix");
2534 static struct pernet_operations unix_net_ops = {
2535 .init = unix_net_init,
2536 .exit = unix_net_exit,
2539 static int __init af_unix_init(void)
2542 struct sk_buff *dummy_skb;
2544 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2546 rc = proto_register(&unix_proto, 1);
2548 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2553 sock_register(&unix_family_ops);
2554 register_pernet_subsys(&unix_net_ops);
2559 static void __exit af_unix_exit(void)
2561 sock_unregister(PF_UNIX);
2562 proto_unregister(&unix_proto);
2563 unregister_pernet_subsys(&unix_net_ops);
2566 /* Earlier than device_initcall() so that other drivers invoking
2567 request_module() don't end up in a loop when modprobe tries
2568 to use a UNIX socket. But later than subsys_initcall() because
2569 we depend on stuff initialised there */
2570 fs_initcall(af_unix_init);
2571 module_exit(af_unix_exit);
2573 MODULE_LICENSE("GPL");
2574 MODULE_ALIAS_NETPROTO(PF_UNIX);