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->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 */
1475 #define MAX_RECURSION_LEVEL 4
1477 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1480 unsigned char max_level = 0;
1481 int unix_sock_count = 0;
1483 for (i = scm->fp->count - 1; i >= 0; i--) {
1484 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1488 max_level = max(max_level,
1489 unix_sk(sk)->recursion_level);
1492 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1493 return -ETOOMANYREFS;
1496 * Need to duplicate file references for the sake of garbage
1497 * collection. Otherwise a socket in the fps might become a
1498 * candidate for GC while the skb is not yet queued.
1500 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1501 if (!UNIXCB(skb).fp)
1504 if (unix_sock_count) {
1505 for (i = scm->fp->count - 1; i >= 0; i--)
1506 unix_inflight(scm->fp->fp[i]);
1511 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1515 UNIXCB(skb).pid = get_pid(scm->pid);
1517 UNIXCB(skb).cred = get_cred(scm->cred);
1518 UNIXCB(skb).fp = NULL;
1519 if (scm->fp && send_fds)
1520 err = unix_attach_fds(scm, skb);
1522 skb->destructor = unix_destruct_scm;
1527 * Some apps rely on write() giving SCM_CREDENTIALS
1528 * We include credentials if source or destination socket
1529 * asserted SOCK_PASSCRED.
1531 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1532 const struct sock *other)
1534 if (UNIXCB(skb).cred)
1536 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1537 !other->sk_socket ||
1538 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1539 UNIXCB(skb).pid = get_pid(task_tgid(current));
1540 UNIXCB(skb).cred = get_current_cred();
1545 * Send AF_UNIX data.
1548 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1549 struct msghdr *msg, size_t len)
1551 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1552 struct sock *sk = sock->sk;
1553 struct net *net = sock_net(sk);
1554 struct unix_sock *u = unix_sk(sk);
1555 struct sockaddr_un *sunaddr = msg->msg_name;
1556 struct sock *other = NULL;
1557 int namelen = 0; /* fake GCC */
1560 struct sk_buff *skb;
1562 struct scm_cookie tmp_scm;
1566 if (NULL == siocb->scm)
1567 siocb->scm = &tmp_scm;
1569 err = scm_send(sock, msg, siocb->scm, false);
1574 if (msg->msg_flags&MSG_OOB)
1577 if (msg->msg_namelen) {
1578 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1585 other = unix_peer_get(sk);
1590 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1591 && (err = unix_autobind(sock)) != 0)
1595 if (len > sk->sk_sndbuf - 32)
1598 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1602 err = unix_scm_to_skb(siocb->scm, skb, true);
1605 max_level = err + 1;
1606 unix_get_secdata(siocb->scm, skb);
1608 skb_reset_transport_header(skb);
1609 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1613 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1618 if (sunaddr == NULL)
1621 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1627 if (sk_filter(other, skb) < 0) {
1628 /* Toss the packet but do not return any error to the sender */
1634 unix_state_lock(other);
1637 if (!unix_may_send(sk, other))
1640 if (unlikely(sock_flag(other, SOCK_DEAD))) {
1642 * Check with 1003.1g - what should
1645 unix_state_unlock(other);
1649 unix_state_lock(sk);
1652 if (unix_peer(sk) == other) {
1653 unix_peer(sk) = NULL;
1654 unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1656 unix_state_unlock(sk);
1658 unix_dgram_disconnected(sk, other);
1660 err = -ECONNREFUSED;
1662 unix_state_unlock(sk);
1672 if (other->sk_shutdown & RCV_SHUTDOWN)
1675 if (sk->sk_type != SOCK_SEQPACKET) {
1676 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1681 if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1683 timeo = unix_wait_for_peer(other, timeo);
1685 err = sock_intr_errno(timeo);
1686 if (signal_pending(current))
1693 unix_state_unlock(other);
1694 unix_state_double_lock(sk, other);
1697 if (unix_peer(sk) != other ||
1698 unix_dgram_peer_wake_me(sk, other)) {
1706 goto restart_locked;
1710 if (unlikely(sk_locked))
1711 unix_state_unlock(sk);
1713 if (sock_flag(other, SOCK_RCVTSTAMP))
1714 __net_timestamp(skb);
1715 maybe_add_creds(skb, sock, other);
1716 skb_queue_tail(&other->sk_receive_queue, skb);
1717 if (max_level > unix_sk(other)->recursion_level)
1718 unix_sk(other)->recursion_level = max_level;
1719 unix_state_unlock(other);
1720 other->sk_data_ready(other, len);
1722 scm_destroy(siocb->scm);
1727 unix_state_unlock(sk);
1728 unix_state_unlock(other);
1734 scm_destroy(siocb->scm);
1739 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1740 struct msghdr *msg, size_t len)
1742 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1743 struct sock *sk = sock->sk;
1744 struct sock *other = NULL;
1746 struct sk_buff *skb;
1748 struct scm_cookie tmp_scm;
1749 bool fds_sent = false;
1752 if (NULL == siocb->scm)
1753 siocb->scm = &tmp_scm;
1755 err = scm_send(sock, msg, siocb->scm, false);
1760 if (msg->msg_flags&MSG_OOB)
1763 if (msg->msg_namelen) {
1764 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1768 other = unix_peer(sk);
1773 if (sk->sk_shutdown & SEND_SHUTDOWN)
1776 while (sent < len) {
1778 * Optimisation for the fact that under 0.01% of X
1779 * messages typically need breaking up.
1784 /* Keep two messages in the pipe so it schedules better */
1785 if (size > ((sk->sk_sndbuf >> 1) - 64))
1786 size = (sk->sk_sndbuf >> 1) - 64;
1788 if (size > SKB_MAX_ALLOC)
1789 size = SKB_MAX_ALLOC;
1795 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1802 * If you pass two values to the sock_alloc_send_skb
1803 * it tries to grab the large buffer with GFP_NOFS
1804 * (which can fail easily), and if it fails grab the
1805 * fallback size buffer which is under a page and will
1808 size = min_t(int, size, skb_tailroom(skb));
1811 /* Only send the fds in the first buffer */
1812 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1817 max_level = err + 1;
1820 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1826 unix_state_lock(other);
1828 if (sock_flag(other, SOCK_DEAD) ||
1829 (other->sk_shutdown & RCV_SHUTDOWN))
1832 maybe_add_creds(skb, sock, other);
1833 skb_queue_tail(&other->sk_receive_queue, skb);
1834 if (max_level > unix_sk(other)->recursion_level)
1835 unix_sk(other)->recursion_level = max_level;
1836 unix_state_unlock(other);
1837 other->sk_data_ready(other, size);
1841 scm_destroy(siocb->scm);
1847 unix_state_unlock(other);
1850 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1851 send_sig(SIGPIPE, current, 0);
1854 scm_destroy(siocb->scm);
1856 return sent ? : err;
1859 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1860 struct msghdr *msg, size_t len)
1863 struct sock *sk = sock->sk;
1865 err = sock_error(sk);
1869 if (sk->sk_state != TCP_ESTABLISHED)
1872 if (msg->msg_namelen)
1873 msg->msg_namelen = 0;
1875 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1878 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1879 struct msghdr *msg, size_t size,
1882 struct sock *sk = sock->sk;
1884 if (sk->sk_state != TCP_ESTABLISHED)
1887 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1890 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1892 struct unix_sock *u = unix_sk(sk);
1895 msg->msg_namelen = u->addr->len;
1896 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1900 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1901 struct msghdr *msg, size_t size,
1904 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1905 struct scm_cookie tmp_scm;
1906 struct sock *sk = sock->sk;
1907 struct unix_sock *u = unix_sk(sk);
1908 int noblock = flags & MSG_DONTWAIT;
1909 struct sk_buff *skb;
1916 err = mutex_lock_interruptible(&u->readlock);
1917 if (unlikely(err)) {
1918 /* recvmsg() in non blocking mode is supposed to return -EAGAIN
1919 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
1921 err = noblock ? -EAGAIN : -ERESTARTSYS;
1925 skb = skb_recv_datagram(sk, flags, noblock, &err);
1927 unix_state_lock(sk);
1928 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1929 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1930 (sk->sk_shutdown & RCV_SHUTDOWN))
1932 unix_state_unlock(sk);
1936 wake_up_interruptible_sync_poll(&u->peer_wait,
1937 POLLOUT | POLLWRNORM | POLLWRBAND);
1940 unix_copy_addr(msg, skb->sk);
1942 if (size > skb->len)
1944 else if (size < skb->len)
1945 msg->msg_flags |= MSG_TRUNC;
1947 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1951 if (sock_flag(sk, SOCK_RCVTSTAMP))
1952 __sock_recv_timestamp(msg, sk, skb);
1955 siocb->scm = &tmp_scm;
1956 memset(&tmp_scm, 0, sizeof(tmp_scm));
1958 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1959 unix_set_secdata(siocb->scm, skb);
1961 if (!(flags & MSG_PEEK)) {
1963 unix_detach_fds(siocb->scm, skb);
1965 /* It is questionable: on PEEK we could:
1966 - do not return fds - good, but too simple 8)
1967 - return fds, and do not return them on read (old strategy,
1969 - clone fds (I chose it for now, it is the most universal
1972 POSIX 1003.1g does not actually define this clearly
1973 at all. POSIX 1003.1g doesn't define a lot of things
1978 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1982 scm_recv(sock, msg, siocb->scm, flags);
1985 skb_free_datagram(sk, skb);
1987 mutex_unlock(&u->readlock);
1993 * Sleep until data has arrive. But check for races..
1996 static long unix_stream_data_wait(struct sock *sk, long timeo)
2000 unix_state_lock(sk);
2003 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2005 if (!skb_queue_empty(&sk->sk_receive_queue) ||
2007 (sk->sk_shutdown & RCV_SHUTDOWN) ||
2008 signal_pending(current) ||
2012 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
2013 unix_state_unlock(sk);
2014 timeo = schedule_timeout(timeo);
2015 unix_state_lock(sk);
2017 if (sock_flag(sk, SOCK_DEAD))
2020 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
2023 finish_wait(sk_sleep(sk), &wait);
2024 unix_state_unlock(sk);
2030 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
2031 struct msghdr *msg, size_t size,
2034 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
2035 struct scm_cookie tmp_scm;
2036 struct sock *sk = sock->sk;
2037 struct unix_sock *u = unix_sk(sk);
2038 struct sockaddr_un *sunaddr = msg->msg_name;
2040 int noblock = flags & MSG_DONTWAIT;
2041 int check_creds = 0;
2047 if (sk->sk_state != TCP_ESTABLISHED)
2054 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
2055 timeo = sock_rcvtimeo(sk, noblock);
2057 /* Lock the socket to prevent queue disordering
2058 * while sleeps in memcpy_tomsg
2062 siocb->scm = &tmp_scm;
2063 memset(&tmp_scm, 0, sizeof(tmp_scm));
2066 mutex_lock(&u->readlock);
2070 struct sk_buff *skb;
2072 unix_state_lock(sk);
2073 if (sock_flag(sk, SOCK_DEAD)) {
2077 skb = skb_peek(&sk->sk_receive_queue);
2079 unix_sk(sk)->recursion_level = 0;
2080 if (copied >= target)
2084 * POSIX 1003.1g mandates this order.
2087 err = sock_error(sk);
2090 if (sk->sk_shutdown & RCV_SHUTDOWN)
2093 unix_state_unlock(sk);
2097 mutex_unlock(&u->readlock);
2099 timeo = unix_stream_data_wait(sk, timeo);
2101 if (signal_pending(current)) {
2102 err = sock_intr_errno(timeo);
2103 scm_destroy(siocb->scm);
2107 mutex_lock(&u->readlock);
2110 unix_state_unlock(sk);
2113 unix_state_unlock(sk);
2116 /* Never glue messages from different writers */
2117 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
2118 (UNIXCB(skb).cred != siocb->scm->cred))
2120 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2121 /* Copy credentials */
2122 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
2126 /* Copy address just once */
2128 unix_copy_addr(msg, skb->sk);
2132 chunk = min_t(unsigned int, skb->len, size);
2133 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
2141 /* Mark read part of skb as used */
2142 if (!(flags & MSG_PEEK)) {
2143 skb_pull(skb, chunk);
2146 unix_detach_fds(siocb->scm, skb);
2151 skb_unlink(skb, &sk->sk_receive_queue);
2157 /* It is questionable, see note in unix_dgram_recvmsg.
2160 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
2166 mutex_unlock(&u->readlock);
2167 scm_recv(sock, msg, siocb->scm, flags);
2169 return copied ? : err;
2172 static int unix_shutdown(struct socket *sock, int mode)
2174 struct sock *sk = sock->sk;
2177 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2182 unix_state_lock(sk);
2183 sk->sk_shutdown |= mode;
2184 other = unix_peer(sk);
2187 unix_state_unlock(sk);
2188 sk->sk_state_change(sk);
2191 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2195 if (mode&RCV_SHUTDOWN)
2196 peer_mode |= SEND_SHUTDOWN;
2197 if (mode&SEND_SHUTDOWN)
2198 peer_mode |= RCV_SHUTDOWN;
2199 unix_state_lock(other);
2200 other->sk_shutdown |= peer_mode;
2201 unix_state_unlock(other);
2202 other->sk_state_change(other);
2203 if (peer_mode == SHUTDOWN_MASK)
2204 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2205 else if (peer_mode & RCV_SHUTDOWN)
2206 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2214 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2216 struct sock *sk = sock->sk;
2222 amount = sk_wmem_alloc_get(sk);
2223 err = put_user(amount, (int __user *)arg);
2227 struct sk_buff *skb;
2229 if (sk->sk_state == TCP_LISTEN) {
2234 spin_lock(&sk->sk_receive_queue.lock);
2235 if (sk->sk_type == SOCK_STREAM ||
2236 sk->sk_type == SOCK_SEQPACKET) {
2237 skb_queue_walk(&sk->sk_receive_queue, skb)
2240 skb = skb_peek(&sk->sk_receive_queue);
2244 spin_unlock(&sk->sk_receive_queue.lock);
2245 err = put_user(amount, (int __user *)arg);
2256 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2258 struct sock *sk = sock->sk;
2261 sock_poll_wait(file, sk_sleep(sk), wait);
2264 /* exceptional events? */
2267 if (sk->sk_shutdown == SHUTDOWN_MASK)
2269 if (sk->sk_shutdown & RCV_SHUTDOWN)
2270 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2273 if (!skb_queue_empty(&sk->sk_receive_queue))
2274 mask |= POLLIN | POLLRDNORM;
2276 /* Connection-based need to check for termination and startup */
2277 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2278 sk->sk_state == TCP_CLOSE)
2282 * we set writable also when the other side has shut down the
2283 * connection. This prevents stuck sockets.
2285 if (unix_writable(sk))
2286 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2291 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2294 struct sock *sk = sock->sk, *other;
2295 unsigned int mask, writable;
2297 sock_poll_wait(file, sk_sleep(sk), wait);
2300 /* exceptional events? */
2301 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2303 if (sk->sk_shutdown & RCV_SHUTDOWN)
2304 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2305 if (sk->sk_shutdown == SHUTDOWN_MASK)
2309 if (!skb_queue_empty(&sk->sk_receive_queue))
2310 mask |= POLLIN | POLLRDNORM;
2312 /* Connection-based need to check for termination and startup */
2313 if (sk->sk_type == SOCK_SEQPACKET) {
2314 if (sk->sk_state == TCP_CLOSE)
2316 /* connection hasn't started yet? */
2317 if (sk->sk_state == TCP_SYN_SENT)
2321 /* No write status requested, avoid expensive OUT tests. */
2322 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2325 writable = unix_writable(sk);
2327 unix_state_lock(sk);
2329 other = unix_peer(sk);
2330 if (other && unix_peer(other) != sk &&
2331 unix_recvq_full(other) &&
2332 unix_dgram_peer_wake_me(sk, other))
2335 unix_state_unlock(sk);
2339 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2341 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2346 #ifdef CONFIG_PROC_FS
2347 static struct sock *first_unix_socket(int *i)
2349 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2350 if (!hlist_empty(&unix_socket_table[*i]))
2351 return __sk_head(&unix_socket_table[*i]);
2356 static struct sock *next_unix_socket(int *i, struct sock *s)
2358 struct sock *next = sk_next(s);
2359 /* More in this chain? */
2362 /* Look for next non-empty chain. */
2363 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2364 if (!hlist_empty(&unix_socket_table[*i]))
2365 return __sk_head(&unix_socket_table[*i]);
2370 struct unix_iter_state {
2371 struct seq_net_private p;
2375 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2377 struct unix_iter_state *iter = seq->private;
2381 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2382 if (sock_net(s) != seq_file_net(seq))
2391 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2392 __acquires(unix_table_lock)
2394 spin_lock(&unix_table_lock);
2395 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2398 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2400 struct unix_iter_state *iter = seq->private;
2401 struct sock *sk = v;
2404 if (v == SEQ_START_TOKEN)
2405 sk = first_unix_socket(&iter->i);
2407 sk = next_unix_socket(&iter->i, sk);
2408 while (sk && (sock_net(sk) != seq_file_net(seq)))
2409 sk = next_unix_socket(&iter->i, sk);
2413 static void unix_seq_stop(struct seq_file *seq, void *v)
2414 __releases(unix_table_lock)
2416 spin_unlock(&unix_table_lock);
2419 static int unix_seq_show(struct seq_file *seq, void *v)
2422 if (v == SEQ_START_TOKEN)
2423 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2427 struct unix_sock *u = unix_sk(s);
2430 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2432 atomic_read(&s->sk_refcnt),
2434 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2437 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2438 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2446 len = u->addr->len - sizeof(short);
2447 if (!UNIX_ABSTRACT(s))
2453 for ( ; i < len; i++)
2454 seq_putc(seq, u->addr->name->sun_path[i]);
2456 unix_state_unlock(s);
2457 seq_putc(seq, '\n');
2463 static const struct seq_operations unix_seq_ops = {
2464 .start = unix_seq_start,
2465 .next = unix_seq_next,
2466 .stop = unix_seq_stop,
2467 .show = unix_seq_show,
2470 static int unix_seq_open(struct inode *inode, struct file *file)
2472 return seq_open_net(inode, file, &unix_seq_ops,
2473 sizeof(struct unix_iter_state));
2476 static const struct file_operations unix_seq_fops = {
2477 .owner = THIS_MODULE,
2478 .open = unix_seq_open,
2480 .llseek = seq_lseek,
2481 .release = seq_release_net,
2486 static const struct net_proto_family unix_family_ops = {
2488 .create = unix_create,
2489 .owner = THIS_MODULE,
2493 static int __net_init unix_net_init(struct net *net)
2495 int error = -ENOMEM;
2497 net->unx.sysctl_max_dgram_qlen = 10;
2498 if (unix_sysctl_register(net))
2501 #ifdef CONFIG_PROC_FS
2502 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2503 unix_sysctl_unregister(net);
2512 static void __net_exit unix_net_exit(struct net *net)
2514 unix_sysctl_unregister(net);
2515 proc_net_remove(net, "unix");
2518 static struct pernet_operations unix_net_ops = {
2519 .init = unix_net_init,
2520 .exit = unix_net_exit,
2523 static int __init af_unix_init(void)
2526 struct sk_buff *dummy_skb;
2528 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2530 rc = proto_register(&unix_proto, 1);
2532 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2537 sock_register(&unix_family_ops);
2538 register_pernet_subsys(&unix_net_ops);
2543 static void __exit af_unix_exit(void)
2545 sock_unregister(PF_UNIX);
2546 proto_unregister(&unix_proto);
2547 unregister_pernet_subsys(&unix_net_ops);
2550 /* Earlier than device_initcall() so that other drivers invoking
2551 request_module() don't end up in a loop when modprobe tries
2552 to use a UNIX socket. But later than subsys_initcall() because
2553 we depend on stuff initialised there */
2554 fs_initcall(af_unix_init);
2555 module_exit(af_unix_exit);
2557 MODULE_LICENSE("GPL");
2558 MODULE_ALIAS_NETPROTO(PF_UNIX);