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_t unix_nr_socks = ATOMIC_INIT(0);
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 rwlock.
150 static inline unsigned unix_hash_fold(__wsum n)
152 unsigned hash = (__force unsigned)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] doesnt 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((char*)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 net *net, 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 (!net_eq(sock_net(s), net))
298 if(dentry && dentry->d_inode == i)
306 spin_unlock(&unix_table_lock);
310 static inline int unix_writable(struct sock *sk)
312 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
315 static void unix_write_space(struct sock *sk)
317 read_lock(&sk->sk_callback_lock);
318 if (unix_writable(sk)) {
319 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
320 wake_up_interruptible_sync(sk->sk_sleep);
321 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
323 read_unlock(&sk->sk_callback_lock);
326 /* When dgram socket disconnects (or changes its peer), we clear its receive
327 * queue of packets arrived from previous peer. First, it allows to do
328 * flow control based only on wmem_alloc; second, sk connected to peer
329 * may receive messages only from that peer. */
330 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
332 if (!skb_queue_empty(&sk->sk_receive_queue)) {
333 skb_queue_purge(&sk->sk_receive_queue);
334 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
336 /* If one link of bidirectional dgram pipe is disconnected,
337 * we signal error. Messages are lost. Do not make this,
338 * when peer was not connected to us.
340 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
341 other->sk_err = ECONNRESET;
342 other->sk_error_report(other);
347 static void unix_sock_destructor(struct sock *sk)
349 struct unix_sock *u = unix_sk(sk);
351 skb_queue_purge(&sk->sk_receive_queue);
353 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
354 WARN_ON(!sk_unhashed(sk));
355 WARN_ON(sk->sk_socket);
356 if (!sock_flag(sk, SOCK_DEAD)) {
357 printk("Attempt to release alive unix socket: %p\n", sk);
362 unix_release_addr(u->addr);
364 atomic_dec(&unix_nr_socks);
365 #ifdef UNIX_REFCNT_DEBUG
366 printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk, atomic_read(&unix_nr_socks));
370 static int unix_release_sock (struct sock *sk, int embrion)
372 struct unix_sock *u = unix_sk(sk);
373 struct dentry *dentry;
374 struct vfsmount *mnt;
379 unix_remove_socket(sk);
384 sk->sk_shutdown = SHUTDOWN_MASK;
389 state = sk->sk_state;
390 sk->sk_state = TCP_CLOSE;
391 unix_state_unlock(sk);
393 wake_up_interruptible_all(&u->peer_wait);
395 skpair=unix_peer(sk);
398 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
399 unix_state_lock(skpair);
401 skpair->sk_shutdown = SHUTDOWN_MASK;
402 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
403 skpair->sk_err = ECONNRESET;
404 unix_state_unlock(skpair);
405 skpair->sk_state_change(skpair);
406 read_lock(&skpair->sk_callback_lock);
407 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
408 read_unlock(&skpair->sk_callback_lock);
410 sock_put(skpair); /* It may now die */
411 unix_peer(sk) = NULL;
414 /* Try to flush out this socket. Throw out buffers at least */
416 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
417 if (state==TCP_LISTEN)
418 unix_release_sock(skb->sk, 1);
419 /* passed fds are erased in the kfree_skb hook */
430 /* ---- Socket is dead now and most probably destroyed ---- */
433 * Fixme: BSD difference: In BSD all sockets connected to use get
434 * ECONNRESET and we die on the spot. In Linux we behave
435 * like files and pipes do and wait for the last
438 * Can't we simply set sock->err?
440 * What the above comment does talk about? --ANK(980817)
443 if (unix_tot_inflight)
444 unix_gc(); /* Garbage collect fds */
449 static int unix_listen(struct socket *sock, int backlog)
452 struct sock *sk = sock->sk;
453 struct unix_sock *u = unix_sk(sk);
456 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
457 goto out; /* Only stream/seqpacket sockets accept */
460 goto out; /* No listens on an unbound socket */
462 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
464 if (backlog > sk->sk_max_ack_backlog)
465 wake_up_interruptible_all(&u->peer_wait);
466 sk->sk_max_ack_backlog = backlog;
467 sk->sk_state = TCP_LISTEN;
468 /* set credentials so connect can copy them */
469 sk->sk_peercred.pid = task_tgid_vnr(current);
470 current_euid_egid(&sk->sk_peercred.uid, &sk->sk_peercred.gid);
474 unix_state_unlock(sk);
479 static int unix_release(struct socket *);
480 static int unix_bind(struct socket *, struct sockaddr *, int);
481 static int unix_stream_connect(struct socket *, struct sockaddr *,
482 int addr_len, int flags);
483 static int unix_socketpair(struct socket *, struct socket *);
484 static int unix_accept(struct socket *, struct socket *, int);
485 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
486 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
487 static unsigned int unix_dgram_poll(struct file *, struct socket *,
489 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
490 static int unix_shutdown(struct socket *, int);
491 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
492 struct msghdr *, size_t);
493 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
494 struct msghdr *, size_t, int);
495 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
496 struct msghdr *, size_t);
497 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
498 struct msghdr *, size_t, int);
499 static int unix_dgram_connect(struct socket *, struct sockaddr *,
501 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
502 struct msghdr *, size_t);
504 static const struct proto_ops unix_stream_ops = {
506 .owner = THIS_MODULE,
507 .release = unix_release,
509 .connect = unix_stream_connect,
510 .socketpair = unix_socketpair,
511 .accept = unix_accept,
512 .getname = unix_getname,
515 .listen = unix_listen,
516 .shutdown = unix_shutdown,
517 .setsockopt = sock_no_setsockopt,
518 .getsockopt = sock_no_getsockopt,
519 .sendmsg = unix_stream_sendmsg,
520 .recvmsg = unix_stream_recvmsg,
521 .mmap = sock_no_mmap,
522 .sendpage = sock_no_sendpage,
525 static const struct proto_ops unix_dgram_ops = {
527 .owner = THIS_MODULE,
528 .release = unix_release,
530 .connect = unix_dgram_connect,
531 .socketpair = unix_socketpair,
532 .accept = sock_no_accept,
533 .getname = unix_getname,
534 .poll = unix_dgram_poll,
536 .listen = sock_no_listen,
537 .shutdown = unix_shutdown,
538 .setsockopt = sock_no_setsockopt,
539 .getsockopt = sock_no_getsockopt,
540 .sendmsg = unix_dgram_sendmsg,
541 .recvmsg = unix_dgram_recvmsg,
542 .mmap = sock_no_mmap,
543 .sendpage = sock_no_sendpage,
546 static const struct proto_ops unix_seqpacket_ops = {
548 .owner = THIS_MODULE,
549 .release = unix_release,
551 .connect = unix_stream_connect,
552 .socketpair = unix_socketpair,
553 .accept = unix_accept,
554 .getname = unix_getname,
555 .poll = unix_dgram_poll,
557 .listen = unix_listen,
558 .shutdown = unix_shutdown,
559 .setsockopt = sock_no_setsockopt,
560 .getsockopt = sock_no_getsockopt,
561 .sendmsg = unix_seqpacket_sendmsg,
562 .recvmsg = unix_dgram_recvmsg,
563 .mmap = sock_no_mmap,
564 .sendpage = sock_no_sendpage,
567 static struct proto unix_proto = {
569 .owner = THIS_MODULE,
570 .obj_size = sizeof(struct unix_sock),
574 * AF_UNIX sockets do not interact with hardware, hence they
575 * dont trigger interrupts - so it's safe for them to have
576 * bh-unsafe locking for their sk_receive_queue.lock. Split off
577 * this special lock-class by reinitializing the spinlock key:
579 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
581 static struct sock * unix_create1(struct net *net, struct socket *sock)
583 struct sock *sk = NULL;
586 atomic_inc(&unix_nr_socks);
587 if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
590 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
594 sock_init_data(sock,sk);
595 lockdep_set_class(&sk->sk_receive_queue.lock,
596 &af_unix_sk_receive_queue_lock_key);
598 sk->sk_write_space = unix_write_space;
599 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
600 sk->sk_destruct = unix_sock_destructor;
604 spin_lock_init(&u->lock);
605 atomic_long_set(&u->inflight, 0);
606 INIT_LIST_HEAD(&u->link);
607 mutex_init(&u->readlock); /* single task reading lock */
608 init_waitqueue_head(&u->peer_wait);
609 unix_insert_socket(unix_sockets_unbound, sk);
612 atomic_dec(&unix_nr_socks);
616 static int unix_create(struct net *net, struct socket *sock, int protocol)
618 if (protocol && protocol != PF_UNIX)
619 return -EPROTONOSUPPORT;
621 sock->state = SS_UNCONNECTED;
623 switch (sock->type) {
625 sock->ops = &unix_stream_ops;
628 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
632 sock->type=SOCK_DGRAM;
634 sock->ops = &unix_dgram_ops;
637 sock->ops = &unix_seqpacket_ops;
640 return -ESOCKTNOSUPPORT;
643 return unix_create1(net, sock) ? 0 : -ENOMEM;
646 static int unix_release(struct socket *sock)
648 struct sock *sk = sock->sk;
655 return unix_release_sock (sk, 0);
658 static int unix_autobind(struct socket *sock)
660 struct sock *sk = sock->sk;
661 struct net *net = sock_net(sk);
662 struct unix_sock *u = unix_sk(sk);
663 static u32 ordernum = 1;
664 struct unix_address * addr;
667 mutex_lock(&u->readlock);
674 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
678 addr->name->sun_family = AF_UNIX;
679 atomic_set(&addr->refcnt, 1);
682 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
683 addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));
685 spin_lock(&unix_table_lock);
686 ordernum = (ordernum+1)&0xFFFFF;
688 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
690 spin_unlock(&unix_table_lock);
691 /* Sanity yield. It is unusual case, but yet... */
692 if (!(ordernum&0xFF))
696 addr->hash ^= sk->sk_type;
698 __unix_remove_socket(sk);
700 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
701 spin_unlock(&unix_table_lock);
704 out: mutex_unlock(&u->readlock);
708 static struct sock *unix_find_other(struct net *net,
709 struct sockaddr_un *sunname, int len,
710 int type, unsigned hash, int *error)
716 if (sunname->sun_path[0]) {
718 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
721 inode = path.dentry->d_inode;
722 err = inode_permission(inode, MAY_WRITE);
727 if (!S_ISSOCK(inode->i_mode))
729 u = unix_find_socket_byinode(net, inode);
733 if (u->sk_type == type)
734 touch_atime(path.mnt, path.dentry);
739 if (u->sk_type != type) {
745 u=unix_find_socket_byname(net, sunname, len, type, hash);
747 struct dentry *dentry;
748 dentry = unix_sk(u)->dentry;
750 touch_atime(unix_sk(u)->mnt, dentry);
764 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
766 struct sock *sk = sock->sk;
767 struct net *net = sock_net(sk);
768 struct unix_sock *u = unix_sk(sk);
769 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
770 struct dentry * dentry = NULL;
774 struct unix_address *addr;
775 struct hlist_head *list;
778 if (sunaddr->sun_family != AF_UNIX)
781 if (addr_len==sizeof(short)) {
782 err = unix_autobind(sock);
786 err = unix_mkname(sunaddr, addr_len, &hash);
791 mutex_lock(&u->readlock);
798 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
802 memcpy(addr->name, sunaddr, addr_len);
803 addr->len = addr_len;
804 addr->hash = hash ^ sk->sk_type;
805 atomic_set(&addr->refcnt, 1);
807 if (sunaddr->sun_path[0]) {
811 * Get the parent directory, calculate the hash for last
814 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
816 goto out_mknod_parent;
818 dentry = lookup_create(&nd, 0);
819 err = PTR_ERR(dentry);
821 goto out_mknod_unlock;
824 * All right, let's create it.
827 (SOCK_INODE(sock)->i_mode & ~current->fs->umask);
828 err = mnt_want_write(nd.path.mnt);
831 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
832 mnt_drop_write(nd.path.mnt);
835 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
836 dput(nd.path.dentry);
837 nd.path.dentry = dentry;
839 addr->hash = UNIX_HASH_SIZE;
842 spin_lock(&unix_table_lock);
844 if (!sunaddr->sun_path[0]) {
846 if (__unix_find_socket_byname(net, sunaddr, addr_len,
847 sk->sk_type, hash)) {
848 unix_release_addr(addr);
852 list = &unix_socket_table[addr->hash];
854 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
855 u->dentry = nd.path.dentry;
856 u->mnt = nd.path.mnt;
860 __unix_remove_socket(sk);
862 __unix_insert_socket(list, sk);
865 spin_unlock(&unix_table_lock);
867 mutex_unlock(&u->readlock);
874 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
879 unix_release_addr(addr);
883 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
885 if (unlikely(sk1 == sk2) || !sk2) {
886 unix_state_lock(sk1);
890 unix_state_lock(sk1);
891 unix_state_lock_nested(sk2);
893 unix_state_lock(sk2);
894 unix_state_lock_nested(sk1);
898 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
900 if (unlikely(sk1 == sk2) || !sk2) {
901 unix_state_unlock(sk1);
904 unix_state_unlock(sk1);
905 unix_state_unlock(sk2);
908 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
911 struct sock *sk = sock->sk;
912 struct net *net = sock_net(sk);
913 struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr;
918 if (addr->sa_family != AF_UNSPEC) {
919 err = unix_mkname(sunaddr, alen, &hash);
924 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
925 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
929 other=unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
933 unix_state_double_lock(sk, other);
935 /* Apparently VFS overslept socket death. Retry. */
936 if (sock_flag(other, SOCK_DEAD)) {
937 unix_state_double_unlock(sk, other);
943 if (!unix_may_send(sk, other))
946 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
952 * 1003.1g breaking connected state with AF_UNSPEC
955 unix_state_double_lock(sk, other);
959 * If it was connected, reconnect.
962 struct sock *old_peer = unix_peer(sk);
964 unix_state_double_unlock(sk, other);
966 if (other != old_peer)
967 unix_dgram_disconnected(sk, old_peer);
971 unix_state_double_unlock(sk, other);
976 unix_state_double_unlock(sk, other);
982 static long unix_wait_for_peer(struct sock *other, long timeo)
984 struct unix_sock *u = unix_sk(other);
988 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
990 sched = !sock_flag(other, SOCK_DEAD) &&
991 !(other->sk_shutdown & RCV_SHUTDOWN) &&
992 unix_recvq_full(other);
994 unix_state_unlock(other);
997 timeo = schedule_timeout(timeo);
999 finish_wait(&u->peer_wait, &wait);
1003 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1004 int addr_len, int flags)
1006 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1007 struct sock *sk = sock->sk;
1008 struct net *net = sock_net(sk);
1009 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1010 struct sock *newsk = NULL;
1011 struct sock *other = NULL;
1012 struct sk_buff *skb = NULL;
1018 err = unix_mkname(sunaddr, addr_len, &hash);
1023 if (test_bit(SOCK_PASSCRED, &sock->flags)
1024 && !u->addr && (err = unix_autobind(sock)) != 0)
1027 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1029 /* First of all allocate resources.
1030 If we will make it after state is locked,
1031 we will have to recheck all again in any case.
1036 /* create new sock for complete connection */
1037 newsk = unix_create1(sock_net(sk), NULL);
1041 /* Allocate skb for sending to listening sock */
1042 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1047 /* Find listening sock. */
1048 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1052 /* Latch state of peer */
1053 unix_state_lock(other);
1055 /* Apparently VFS overslept socket death. Retry. */
1056 if (sock_flag(other, SOCK_DEAD)) {
1057 unix_state_unlock(other);
1062 err = -ECONNREFUSED;
1063 if (other->sk_state != TCP_LISTEN)
1066 if (unix_recvq_full(other)) {
1071 timeo = unix_wait_for_peer(other, timeo);
1073 err = sock_intr_errno(timeo);
1074 if (signal_pending(current))
1082 It is tricky place. We need to grab write lock and cannot
1083 drop lock on peer. It is dangerous because deadlock is
1084 possible. Connect to self case and simultaneous
1085 attempt to connect are eliminated by checking socket
1086 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1087 check this before attempt to grab lock.
1089 Well, and we have to recheck the state after socket locked.
1095 /* This is ok... continue with connect */
1097 case TCP_ESTABLISHED:
1098 /* Socket is already connected */
1106 unix_state_lock_nested(sk);
1108 if (sk->sk_state != st) {
1109 unix_state_unlock(sk);
1110 unix_state_unlock(other);
1115 err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1117 unix_state_unlock(sk);
1121 /* The way is open! Fastly set all the necessary fields... */
1124 unix_peer(newsk) = sk;
1125 newsk->sk_state = TCP_ESTABLISHED;
1126 newsk->sk_type = sk->sk_type;
1127 newsk->sk_peercred.pid = task_tgid_vnr(current);
1128 current_euid_egid(&newsk->sk_peercred.uid, &newsk->sk_peercred.gid);
1129 newu = unix_sk(newsk);
1130 newsk->sk_sleep = &newu->peer_wait;
1131 otheru = unix_sk(other);
1133 /* copy address information from listening to new sock*/
1135 atomic_inc(&otheru->addr->refcnt);
1136 newu->addr = otheru->addr;
1138 if (otheru->dentry) {
1139 newu->dentry = dget(otheru->dentry);
1140 newu->mnt = mntget(otheru->mnt);
1143 /* Set credentials */
1144 sk->sk_peercred = other->sk_peercred;
1146 sock->state = SS_CONNECTED;
1147 sk->sk_state = TCP_ESTABLISHED;
1150 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1151 unix_peer(sk) = newsk;
1153 unix_state_unlock(sk);
1155 /* take ten and and send info to listening sock */
1156 spin_lock(&other->sk_receive_queue.lock);
1157 __skb_queue_tail(&other->sk_receive_queue, skb);
1158 spin_unlock(&other->sk_receive_queue.lock);
1159 unix_state_unlock(other);
1160 other->sk_data_ready(other, 0);
1166 unix_state_unlock(other);
1172 unix_release_sock(newsk, 0);
1178 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1180 struct sock *ska=socka->sk, *skb = sockb->sk;
1182 /* Join our sockets back to back */
1187 ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
1188 current_euid_egid(&skb->sk_peercred.uid, &skb->sk_peercred.gid);
1189 ska->sk_peercred.uid = skb->sk_peercred.uid;
1190 ska->sk_peercred.gid = skb->sk_peercred.gid;
1192 if (ska->sk_type != SOCK_DGRAM) {
1193 ska->sk_state = TCP_ESTABLISHED;
1194 skb->sk_state = TCP_ESTABLISHED;
1195 socka->state = SS_CONNECTED;
1196 sockb->state = SS_CONNECTED;
1201 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1203 struct sock *sk = sock->sk;
1205 struct sk_buff *skb;
1209 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
1213 if (sk->sk_state != TCP_LISTEN)
1216 /* If socket state is TCP_LISTEN it cannot change (for now...),
1217 * so that no locks are necessary.
1220 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1222 /* This means receive shutdown. */
1229 skb_free_datagram(sk, skb);
1230 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1232 /* attach accepted sock to socket */
1233 unix_state_lock(tsk);
1234 newsock->state = SS_CONNECTED;
1235 sock_graft(tsk, newsock);
1236 unix_state_unlock(tsk);
1244 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1246 struct sock *sk = sock->sk;
1247 struct unix_sock *u;
1248 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1252 sk = unix_peer_get(sk);
1263 unix_state_lock(sk);
1265 sunaddr->sun_family = AF_UNIX;
1266 sunaddr->sun_path[0] = 0;
1267 *uaddr_len = sizeof(short);
1269 struct unix_address *addr = u->addr;
1271 *uaddr_len = addr->len;
1272 memcpy(sunaddr, addr->name, *uaddr_len);
1274 unix_state_unlock(sk);
1280 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1284 scm->fp = UNIXCB(skb).fp;
1285 skb->destructor = sock_wfree;
1286 UNIXCB(skb).fp = NULL;
1288 for (i=scm->fp->count-1; i>=0; i--)
1289 unix_notinflight(scm->fp->fp[i]);
1292 static void unix_destruct_fds(struct sk_buff *skb)
1294 struct scm_cookie scm;
1295 memset(&scm, 0, sizeof(scm));
1296 unix_detach_fds(&scm, skb);
1298 /* Alas, it calls VFS */
1299 /* So fscking what? fput() had been SMP-safe since the last Summer */
1304 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1309 * Need to duplicate file references for the sake of garbage
1310 * collection. Otherwise a socket in the fps might become a
1311 * candidate for GC while the skb is not yet queued.
1313 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1314 if (!UNIXCB(skb).fp)
1317 for (i=scm->fp->count-1; i>=0; i--)
1318 unix_inflight(scm->fp->fp[i]);
1319 skb->destructor = unix_destruct_fds;
1324 * Send AF_UNIX data.
1327 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1328 struct msghdr *msg, size_t len)
1330 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1331 struct sock *sk = sock->sk;
1332 struct net *net = sock_net(sk);
1333 struct unix_sock *u = unix_sk(sk);
1334 struct sockaddr_un *sunaddr=msg->msg_name;
1335 struct sock *other = NULL;
1336 int namelen = 0; /* fake GCC */
1339 struct sk_buff *skb;
1341 struct scm_cookie tmp_scm;
1343 if (NULL == siocb->scm)
1344 siocb->scm = &tmp_scm;
1346 err = scm_send(sock, msg, siocb->scm);
1351 if (msg->msg_flags&MSG_OOB)
1354 if (msg->msg_namelen) {
1355 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1362 other = unix_peer_get(sk);
1367 if (test_bit(SOCK_PASSCRED, &sock->flags)
1368 && !u->addr && (err = unix_autobind(sock)) != 0)
1372 if (len > sk->sk_sndbuf - 32)
1375 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1379 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1380 if (siocb->scm->fp) {
1381 err = unix_attach_fds(siocb->scm, skb);
1385 unix_get_secdata(siocb->scm, skb);
1387 skb_reset_transport_header(skb);
1388 err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
1392 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1397 if (sunaddr == NULL)
1400 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1406 unix_state_lock(other);
1408 if (!unix_may_send(sk, other))
1411 if (sock_flag(other, SOCK_DEAD)) {
1413 * Check with 1003.1g - what should
1416 unix_state_unlock(other);
1420 unix_state_lock(sk);
1421 if (unix_peer(sk) == other) {
1423 unix_state_unlock(sk);
1425 unix_dgram_disconnected(sk, other);
1427 err = -ECONNREFUSED;
1429 unix_state_unlock(sk);
1439 if (other->sk_shutdown & RCV_SHUTDOWN)
1442 if (sk->sk_type != SOCK_SEQPACKET) {
1443 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1448 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1454 timeo = unix_wait_for_peer(other, timeo);
1456 err = sock_intr_errno(timeo);
1457 if (signal_pending(current))
1463 skb_queue_tail(&other->sk_receive_queue, skb);
1464 unix_state_unlock(other);
1465 other->sk_data_ready(other, len);
1467 scm_destroy(siocb->scm);
1471 unix_state_unlock(other);
1477 scm_destroy(siocb->scm);
1482 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1483 struct msghdr *msg, size_t len)
1485 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1486 struct sock *sk = sock->sk;
1487 struct sock *other = NULL;
1488 struct sockaddr_un *sunaddr=msg->msg_name;
1490 struct sk_buff *skb;
1492 struct scm_cookie tmp_scm;
1494 if (NULL == siocb->scm)
1495 siocb->scm = &tmp_scm;
1497 err = scm_send(sock, msg, siocb->scm);
1502 if (msg->msg_flags&MSG_OOB)
1505 if (msg->msg_namelen) {
1506 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1511 other = unix_peer(sk);
1516 if (sk->sk_shutdown & SEND_SHUTDOWN)
1522 * Optimisation for the fact that under 0.01% of X
1523 * messages typically need breaking up.
1528 /* Keep two messages in the pipe so it schedules better */
1529 if (size > ((sk->sk_sndbuf >> 1) - 64))
1530 size = (sk->sk_sndbuf >> 1) - 64;
1532 if (size > SKB_MAX_ALLOC)
1533 size = SKB_MAX_ALLOC;
1539 skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err);
1545 * If you pass two values to the sock_alloc_send_skb
1546 * it tries to grab the large buffer with GFP_NOFS
1547 * (which can fail easily), and if it fails grab the
1548 * fallback size buffer which is under a page and will
1551 size = min_t(int, size, skb_tailroom(skb));
1553 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1554 if (siocb->scm->fp) {
1555 err = unix_attach_fds(siocb->scm, skb);
1562 if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) {
1567 unix_state_lock(other);
1569 if (sock_flag(other, SOCK_DEAD) ||
1570 (other->sk_shutdown & RCV_SHUTDOWN))
1573 skb_queue_tail(&other->sk_receive_queue, skb);
1574 unix_state_unlock(other);
1575 other->sk_data_ready(other, size);
1579 scm_destroy(siocb->scm);
1585 unix_state_unlock(other);
1588 if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL))
1589 send_sig(SIGPIPE,current,0);
1592 scm_destroy(siocb->scm);
1594 return sent ? : err;
1597 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1598 struct msghdr *msg, size_t len)
1601 struct sock *sk = sock->sk;
1603 err = sock_error(sk);
1607 if (sk->sk_state != TCP_ESTABLISHED)
1610 if (msg->msg_namelen)
1611 msg->msg_namelen = 0;
1613 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1616 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1618 struct unix_sock *u = unix_sk(sk);
1620 msg->msg_namelen = 0;
1622 msg->msg_namelen = u->addr->len;
1623 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1627 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1628 struct msghdr *msg, size_t size,
1631 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1632 struct scm_cookie tmp_scm;
1633 struct sock *sk = sock->sk;
1634 struct unix_sock *u = unix_sk(sk);
1635 int noblock = flags & MSG_DONTWAIT;
1636 struct sk_buff *skb;
1643 msg->msg_namelen = 0;
1645 mutex_lock(&u->readlock);
1647 skb = skb_recv_datagram(sk, flags, noblock, &err);
1649 unix_state_lock(sk);
1650 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1651 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1652 (sk->sk_shutdown & RCV_SHUTDOWN))
1654 unix_state_unlock(sk);
1658 wake_up_interruptible_sync(&u->peer_wait);
1661 unix_copy_addr(msg, skb->sk);
1663 if (size > skb->len)
1665 else if (size < skb->len)
1666 msg->msg_flags |= MSG_TRUNC;
1668 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1673 siocb->scm = &tmp_scm;
1674 memset(&tmp_scm, 0, sizeof(tmp_scm));
1676 siocb->scm->creds = *UNIXCREDS(skb);
1677 unix_set_secdata(siocb->scm, skb);
1679 if (!(flags & MSG_PEEK))
1682 unix_detach_fds(siocb->scm, skb);
1686 /* It is questionable: on PEEK we could:
1687 - do not return fds - good, but too simple 8)
1688 - return fds, and do not return them on read (old strategy,
1690 - clone fds (I chose it for now, it is the most universal
1693 POSIX 1003.1g does not actually define this clearly
1694 at all. POSIX 1003.1g doesn't define a lot of things
1699 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1703 scm_recv(sock, msg, siocb->scm, flags);
1706 skb_free_datagram(sk,skb);
1708 mutex_unlock(&u->readlock);
1714 * Sleep until data has arrive. But check for races..
1717 static long unix_stream_data_wait(struct sock * sk, long timeo)
1721 unix_state_lock(sk);
1724 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
1726 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1728 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1729 signal_pending(current) ||
1733 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1734 unix_state_unlock(sk);
1735 timeo = schedule_timeout(timeo);
1736 unix_state_lock(sk);
1737 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1740 finish_wait(sk->sk_sleep, &wait);
1741 unix_state_unlock(sk);
1747 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1748 struct msghdr *msg, size_t size,
1751 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1752 struct scm_cookie tmp_scm;
1753 struct sock *sk = sock->sk;
1754 struct unix_sock *u = unix_sk(sk);
1755 struct sockaddr_un *sunaddr=msg->msg_name;
1757 int check_creds = 0;
1763 if (sk->sk_state != TCP_ESTABLISHED)
1770 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1771 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1773 msg->msg_namelen = 0;
1775 /* Lock the socket to prevent queue disordering
1776 * while sleeps in memcpy_tomsg
1780 siocb->scm = &tmp_scm;
1781 memset(&tmp_scm, 0, sizeof(tmp_scm));
1784 mutex_lock(&u->readlock);
1789 struct sk_buff *skb;
1791 unix_state_lock(sk);
1792 skb = skb_dequeue(&sk->sk_receive_queue);
1795 if (copied >= target)
1799 * POSIX 1003.1g mandates this order.
1802 if ((err = sock_error(sk)) != 0)
1804 if (sk->sk_shutdown & RCV_SHUTDOWN)
1807 unix_state_unlock(sk);
1811 mutex_unlock(&u->readlock);
1813 timeo = unix_stream_data_wait(sk, timeo);
1815 if (signal_pending(current)) {
1816 err = sock_intr_errno(timeo);
1819 mutex_lock(&u->readlock);
1822 unix_state_unlock(sk);
1825 unix_state_unlock(sk);
1828 /* Never glue messages from different writers */
1829 if (memcmp(UNIXCREDS(skb), &siocb->scm->creds, sizeof(siocb->scm->creds)) != 0) {
1830 skb_queue_head(&sk->sk_receive_queue, skb);
1834 /* Copy credentials */
1835 siocb->scm->creds = *UNIXCREDS(skb);
1839 /* Copy address just once */
1842 unix_copy_addr(msg, skb->sk);
1846 chunk = min_t(unsigned int, skb->len, size);
1847 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1848 skb_queue_head(&sk->sk_receive_queue, skb);
1856 /* Mark read part of skb as used */
1857 if (!(flags & MSG_PEEK))
1859 skb_pull(skb, chunk);
1862 unix_detach_fds(siocb->scm, skb);
1864 /* put the skb back if we didn't use it up.. */
1867 skb_queue_head(&sk->sk_receive_queue, skb);
1878 /* It is questionable, see note in unix_dgram_recvmsg.
1881 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1883 /* put message back and return */
1884 skb_queue_head(&sk->sk_receive_queue, skb);
1889 mutex_unlock(&u->readlock);
1890 scm_recv(sock, msg, siocb->scm, flags);
1892 return copied ? : err;
1895 static int unix_shutdown(struct socket *sock, int mode)
1897 struct sock *sk = sock->sk;
1900 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1903 unix_state_lock(sk);
1904 sk->sk_shutdown |= mode;
1905 other=unix_peer(sk);
1908 unix_state_unlock(sk);
1909 sk->sk_state_change(sk);
1912 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1916 if (mode&RCV_SHUTDOWN)
1917 peer_mode |= SEND_SHUTDOWN;
1918 if (mode&SEND_SHUTDOWN)
1919 peer_mode |= RCV_SHUTDOWN;
1920 unix_state_lock(other);
1921 other->sk_shutdown |= peer_mode;
1922 unix_state_unlock(other);
1923 other->sk_state_change(other);
1924 read_lock(&other->sk_callback_lock);
1925 if (peer_mode == SHUTDOWN_MASK)
1926 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1927 else if (peer_mode & RCV_SHUTDOWN)
1928 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
1929 read_unlock(&other->sk_callback_lock);
1937 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1939 struct sock *sk = sock->sk;
1946 amount = atomic_read(&sk->sk_wmem_alloc);
1947 err = put_user(amount, (int __user *)arg);
1951 struct sk_buff *skb;
1953 if (sk->sk_state == TCP_LISTEN) {
1958 spin_lock(&sk->sk_receive_queue.lock);
1959 if (sk->sk_type == SOCK_STREAM ||
1960 sk->sk_type == SOCK_SEQPACKET) {
1961 skb_queue_walk(&sk->sk_receive_queue, skb)
1964 skb = skb_peek(&sk->sk_receive_queue);
1968 spin_unlock(&sk->sk_receive_queue.lock);
1969 err = put_user(amount, (int __user *)arg);
1980 static unsigned int unix_poll(struct file * file, struct socket *sock, poll_table *wait)
1982 struct sock *sk = sock->sk;
1985 poll_wait(file, sk->sk_sleep, wait);
1988 /* exceptional events? */
1991 if (sk->sk_shutdown == SHUTDOWN_MASK)
1993 if (sk->sk_shutdown & RCV_SHUTDOWN)
1997 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1998 (sk->sk_shutdown & RCV_SHUTDOWN))
1999 mask |= POLLIN | POLLRDNORM;
2001 /* Connection-based need to check for termination and startup */
2002 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && sk->sk_state == TCP_CLOSE)
2006 * we set writable also when the other side has shut down the
2007 * connection. This prevents stuck sockets.
2009 if (unix_writable(sk))
2010 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2015 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2018 struct sock *sk = sock->sk, *other;
2019 unsigned int mask, writable;
2021 poll_wait(file, sk->sk_sleep, wait);
2024 /* exceptional events? */
2025 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2027 if (sk->sk_shutdown & RCV_SHUTDOWN)
2029 if (sk->sk_shutdown == SHUTDOWN_MASK)
2033 if (!skb_queue_empty(&sk->sk_receive_queue) ||
2034 (sk->sk_shutdown & RCV_SHUTDOWN))
2035 mask |= POLLIN | POLLRDNORM;
2037 /* Connection-based need to check for termination and startup */
2038 if (sk->sk_type == SOCK_SEQPACKET) {
2039 if (sk->sk_state == TCP_CLOSE)
2041 /* connection hasn't started yet? */
2042 if (sk->sk_state == TCP_SYN_SENT)
2047 writable = unix_writable(sk);
2049 other = unix_peer_get(sk);
2051 if (unix_peer(other) != sk) {
2052 poll_wait(file, &unix_sk(other)->peer_wait,
2054 if (unix_recvq_full(other))
2063 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2065 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2070 #ifdef CONFIG_PROC_FS
2071 static struct sock *first_unix_socket(int *i)
2073 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2074 if (!hlist_empty(&unix_socket_table[*i]))
2075 return __sk_head(&unix_socket_table[*i]);
2080 static struct sock *next_unix_socket(int *i, struct sock *s)
2082 struct sock *next = sk_next(s);
2083 /* More in this chain? */
2086 /* Look for next non-empty chain. */
2087 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2088 if (!hlist_empty(&unix_socket_table[*i]))
2089 return __sk_head(&unix_socket_table[*i]);
2094 struct unix_iter_state {
2095 struct seq_net_private p;
2098 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2100 struct unix_iter_state *iter = seq->private;
2104 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2105 if (sock_net(s) != seq_file_net(seq))
2115 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2116 __acquires(unix_table_lock)
2118 spin_lock(&unix_table_lock);
2119 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2122 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2124 struct unix_iter_state *iter = seq->private;
2125 struct sock *sk = v;
2128 if (v == SEQ_START_TOKEN)
2129 sk = first_unix_socket(&iter->i);
2131 sk = next_unix_socket(&iter->i, sk);
2132 while (sk && (sock_net(sk) != seq_file_net(seq)))
2133 sk = next_unix_socket(&iter->i, sk);
2137 static void unix_seq_stop(struct seq_file *seq, void *v)
2138 __releases(unix_table_lock)
2140 spin_unlock(&unix_table_lock);
2143 static int unix_seq_show(struct seq_file *seq, void *v)
2146 if (v == SEQ_START_TOKEN)
2147 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2151 struct unix_sock *u = unix_sk(s);
2154 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2156 atomic_read(&s->sk_refcnt),
2158 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2161 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2162 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2170 len = u->addr->len - sizeof(short);
2171 if (!UNIX_ABSTRACT(s))
2177 for ( ; i < len; i++)
2178 seq_putc(seq, u->addr->name->sun_path[i]);
2180 unix_state_unlock(s);
2181 seq_putc(seq, '\n');
2187 static const struct seq_operations unix_seq_ops = {
2188 .start = unix_seq_start,
2189 .next = unix_seq_next,
2190 .stop = unix_seq_stop,
2191 .show = unix_seq_show,
2195 static int unix_seq_open(struct inode *inode, struct file *file)
2197 return seq_open_net(inode, file, &unix_seq_ops,
2198 sizeof(struct unix_iter_state));
2201 static const struct file_operations unix_seq_fops = {
2202 .owner = THIS_MODULE,
2203 .open = unix_seq_open,
2205 .llseek = seq_lseek,
2206 .release = seq_release_net,
2211 static struct net_proto_family unix_family_ops = {
2213 .create = unix_create,
2214 .owner = THIS_MODULE,
2218 static int unix_net_init(struct net *net)
2220 int error = -ENOMEM;
2222 net->unx.sysctl_max_dgram_qlen = 10;
2223 if (unix_sysctl_register(net))
2226 #ifdef CONFIG_PROC_FS
2227 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2228 unix_sysctl_unregister(net);
2237 static void unix_net_exit(struct net *net)
2239 unix_sysctl_unregister(net);
2240 proc_net_remove(net, "unix");
2243 static struct pernet_operations unix_net_ops = {
2244 .init = unix_net_init,
2245 .exit = unix_net_exit,
2248 static int __init af_unix_init(void)
2251 struct sk_buff *dummy_skb;
2253 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2255 rc = proto_register(&unix_proto, 1);
2257 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2262 sock_register(&unix_family_ops);
2263 register_pernet_subsys(&unix_net_ops);
2268 static void __exit af_unix_exit(void)
2270 sock_unregister(PF_UNIX);
2271 proto_unregister(&unix_proto);
2272 unregister_pernet_subsys(&unix_net_ops);
2275 /* Earlier than device_initcall() so that other drivers invoking
2276 request_module() don't end up in a loop when modprobe tries
2277 to use a UNIX socket. But later than subsys_initcall() because
2278 we depend on stuff initialised there */
2279 fs_initcall(af_unix_init);
2280 module_exit(af_unix_exit);
2282 MODULE_LICENSE("GPL");
2283 MODULE_ALIAS_NETPROTO(PF_UNIX);