2 * NET4: Implementation of BSD Unix domain sockets.
4 * Authors: Alan Cox, <alan.cox@linux.org>
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 sk->sk_peercred.uid = current->euid;
471 sk->sk_peercred.gid = current->egid;
475 unix_state_unlock(sk);
480 static int unix_release(struct socket *);
481 static int unix_bind(struct socket *, struct sockaddr *, int);
482 static int unix_stream_connect(struct socket *, struct sockaddr *,
483 int addr_len, int flags);
484 static int unix_socketpair(struct socket *, struct socket *);
485 static int unix_accept(struct socket *, struct socket *, int);
486 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
487 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
488 static unsigned int unix_dgram_poll(struct file *, struct socket *,
490 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
491 static int unix_shutdown(struct socket *, int);
492 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
493 struct msghdr *, size_t);
494 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
495 struct msghdr *, size_t, int);
496 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
497 struct msghdr *, size_t);
498 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
499 struct msghdr *, size_t, int);
500 static int unix_dgram_connect(struct socket *, struct sockaddr *,
502 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
503 struct msghdr *, size_t);
505 static const struct proto_ops unix_stream_ops = {
507 .owner = THIS_MODULE,
508 .release = unix_release,
510 .connect = unix_stream_connect,
511 .socketpair = unix_socketpair,
512 .accept = unix_accept,
513 .getname = unix_getname,
516 .listen = unix_listen,
517 .shutdown = unix_shutdown,
518 .setsockopt = sock_no_setsockopt,
519 .getsockopt = sock_no_getsockopt,
520 .sendmsg = unix_stream_sendmsg,
521 .recvmsg = unix_stream_recvmsg,
522 .mmap = sock_no_mmap,
523 .sendpage = sock_no_sendpage,
526 static const struct proto_ops unix_dgram_ops = {
528 .owner = THIS_MODULE,
529 .release = unix_release,
531 .connect = unix_dgram_connect,
532 .socketpair = unix_socketpair,
533 .accept = sock_no_accept,
534 .getname = unix_getname,
535 .poll = unix_dgram_poll,
537 .listen = sock_no_listen,
538 .shutdown = unix_shutdown,
539 .setsockopt = sock_no_setsockopt,
540 .getsockopt = sock_no_getsockopt,
541 .sendmsg = unix_dgram_sendmsg,
542 .recvmsg = unix_dgram_recvmsg,
543 .mmap = sock_no_mmap,
544 .sendpage = sock_no_sendpage,
547 static const struct proto_ops unix_seqpacket_ops = {
549 .owner = THIS_MODULE,
550 .release = unix_release,
552 .connect = unix_stream_connect,
553 .socketpair = unix_socketpair,
554 .accept = unix_accept,
555 .getname = unix_getname,
556 .poll = unix_dgram_poll,
558 .listen = unix_listen,
559 .shutdown = unix_shutdown,
560 .setsockopt = sock_no_setsockopt,
561 .getsockopt = sock_no_getsockopt,
562 .sendmsg = unix_seqpacket_sendmsg,
563 .recvmsg = unix_dgram_recvmsg,
564 .mmap = sock_no_mmap,
565 .sendpage = sock_no_sendpage,
568 static struct proto unix_proto = {
570 .owner = THIS_MODULE,
571 .obj_size = sizeof(struct unix_sock),
575 * AF_UNIX sockets do not interact with hardware, hence they
576 * dont trigger interrupts - so it's safe for them to have
577 * bh-unsafe locking for their sk_receive_queue.lock. Split off
578 * this special lock-class by reinitializing the spinlock key:
580 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
582 static struct sock * unix_create1(struct net *net, struct socket *sock)
584 struct sock *sk = NULL;
587 atomic_inc(&unix_nr_socks);
588 if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
591 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
595 sock_init_data(sock,sk);
596 lockdep_set_class(&sk->sk_receive_queue.lock,
597 &af_unix_sk_receive_queue_lock_key);
599 sk->sk_write_space = unix_write_space;
600 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
601 sk->sk_destruct = unix_sock_destructor;
605 spin_lock_init(&u->lock);
606 atomic_long_set(&u->inflight, 0);
607 INIT_LIST_HEAD(&u->link);
608 mutex_init(&u->readlock); /* single task reading lock */
609 init_waitqueue_head(&u->peer_wait);
610 unix_insert_socket(unix_sockets_unbound, sk);
613 atomic_dec(&unix_nr_socks);
617 static int unix_create(struct net *net, struct socket *sock, int protocol)
619 if (protocol && protocol != PF_UNIX)
620 return -EPROTONOSUPPORT;
622 sock->state = SS_UNCONNECTED;
624 switch (sock->type) {
626 sock->ops = &unix_stream_ops;
629 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
633 sock->type=SOCK_DGRAM;
635 sock->ops = &unix_dgram_ops;
638 sock->ops = &unix_seqpacket_ops;
641 return -ESOCKTNOSUPPORT;
644 return unix_create1(net, sock) ? 0 : -ENOMEM;
647 static int unix_release(struct socket *sock)
649 struct sock *sk = sock->sk;
656 return unix_release_sock (sk, 0);
659 static int unix_autobind(struct socket *sock)
661 struct sock *sk = sock->sk;
662 struct net *net = sock_net(sk);
663 struct unix_sock *u = unix_sk(sk);
664 static u32 ordernum = 1;
665 struct unix_address * addr;
668 mutex_lock(&u->readlock);
675 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
679 addr->name->sun_family = AF_UNIX;
680 atomic_set(&addr->refcnt, 1);
683 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
684 addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));
686 spin_lock(&unix_table_lock);
687 ordernum = (ordernum+1)&0xFFFFF;
689 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
691 spin_unlock(&unix_table_lock);
692 /* Sanity yield. It is unusual case, but yet... */
693 if (!(ordernum&0xFF))
697 addr->hash ^= sk->sk_type;
699 __unix_remove_socket(sk);
701 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
702 spin_unlock(&unix_table_lock);
705 out: mutex_unlock(&u->readlock);
709 static struct sock *unix_find_other(struct net *net,
710 struct sockaddr_un *sunname, int len,
711 int type, unsigned hash, int *error)
717 if (sunname->sun_path[0]) {
718 err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd);
721 err = vfs_permission(&nd, MAY_WRITE);
726 if (!S_ISSOCK(nd.path.dentry->d_inode->i_mode))
728 u = unix_find_socket_byinode(net, nd.path.dentry->d_inode);
732 if (u->sk_type == type)
733 touch_atime(nd.path.mnt, nd.path.dentry);
738 if (u->sk_type != type) {
744 u=unix_find_socket_byname(net, sunname, len, type, hash);
746 struct dentry *dentry;
747 dentry = unix_sk(u)->dentry;
749 touch_atime(unix_sk(u)->mnt, dentry);
763 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
765 struct sock *sk = sock->sk;
766 struct net *net = sock_net(sk);
767 struct unix_sock *u = unix_sk(sk);
768 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
769 struct dentry * dentry = NULL;
773 struct unix_address *addr;
774 struct hlist_head *list;
777 if (sunaddr->sun_family != AF_UNIX)
780 if (addr_len==sizeof(short)) {
781 err = unix_autobind(sock);
785 err = unix_mkname(sunaddr, addr_len, &hash);
790 mutex_lock(&u->readlock);
797 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
801 memcpy(addr->name, sunaddr, addr_len);
802 addr->len = addr_len;
803 addr->hash = hash ^ sk->sk_type;
804 atomic_set(&addr->refcnt, 1);
806 if (sunaddr->sun_path[0]) {
810 * Get the parent directory, calculate the hash for last
813 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
815 goto out_mknod_parent;
817 dentry = lookup_create(&nd, 0);
818 err = PTR_ERR(dentry);
820 goto out_mknod_unlock;
823 * All right, let's create it.
826 (SOCK_INODE(sock)->i_mode & ~current->fs->umask);
827 err = mnt_want_write(nd.path.mnt);
830 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
831 mnt_drop_write(nd.path.mnt);
834 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
835 dput(nd.path.dentry);
836 nd.path.dentry = dentry;
838 addr->hash = UNIX_HASH_SIZE;
841 spin_lock(&unix_table_lock);
843 if (!sunaddr->sun_path[0]) {
845 if (__unix_find_socket_byname(net, sunaddr, addr_len,
846 sk->sk_type, hash)) {
847 unix_release_addr(addr);
851 list = &unix_socket_table[addr->hash];
853 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
854 u->dentry = nd.path.dentry;
855 u->mnt = nd.path.mnt;
859 __unix_remove_socket(sk);
861 __unix_insert_socket(list, sk);
864 spin_unlock(&unix_table_lock);
866 mutex_unlock(&u->readlock);
873 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
878 unix_release_addr(addr);
882 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
884 if (unlikely(sk1 == sk2) || !sk2) {
885 unix_state_lock(sk1);
889 unix_state_lock(sk1);
890 unix_state_lock_nested(sk2);
892 unix_state_lock(sk2);
893 unix_state_lock_nested(sk1);
897 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
899 if (unlikely(sk1 == sk2) || !sk2) {
900 unix_state_unlock(sk1);
903 unix_state_unlock(sk1);
904 unix_state_unlock(sk2);
907 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
910 struct sock *sk = sock->sk;
911 struct net *net = sock_net(sk);
912 struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr;
917 if (addr->sa_family != AF_UNSPEC) {
918 err = unix_mkname(sunaddr, alen, &hash);
923 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
924 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
928 other=unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
932 unix_state_double_lock(sk, other);
934 /* Apparently VFS overslept socket death. Retry. */
935 if (sock_flag(other, SOCK_DEAD)) {
936 unix_state_double_unlock(sk, other);
942 if (!unix_may_send(sk, other))
945 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
951 * 1003.1g breaking connected state with AF_UNSPEC
954 unix_state_double_lock(sk, other);
958 * If it was connected, reconnect.
961 struct sock *old_peer = unix_peer(sk);
963 unix_state_double_unlock(sk, other);
965 if (other != old_peer)
966 unix_dgram_disconnected(sk, old_peer);
970 unix_state_double_unlock(sk, other);
975 unix_state_double_unlock(sk, other);
981 static long unix_wait_for_peer(struct sock *other, long timeo)
983 struct unix_sock *u = unix_sk(other);
987 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
989 sched = !sock_flag(other, SOCK_DEAD) &&
990 !(other->sk_shutdown & RCV_SHUTDOWN) &&
991 unix_recvq_full(other);
993 unix_state_unlock(other);
996 timeo = schedule_timeout(timeo);
998 finish_wait(&u->peer_wait, &wait);
1002 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1003 int addr_len, int flags)
1005 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1006 struct sock *sk = sock->sk;
1007 struct net *net = sock_net(sk);
1008 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1009 struct sock *newsk = NULL;
1010 struct sock *other = NULL;
1011 struct sk_buff *skb = NULL;
1017 err = unix_mkname(sunaddr, addr_len, &hash);
1022 if (test_bit(SOCK_PASSCRED, &sock->flags)
1023 && !u->addr && (err = unix_autobind(sock)) != 0)
1026 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1028 /* First of all allocate resources.
1029 If we will make it after state is locked,
1030 we will have to recheck all again in any case.
1035 /* create new sock for complete connection */
1036 newsk = unix_create1(sock_net(sk), NULL);
1040 /* Allocate skb for sending to listening sock */
1041 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1046 /* Find listening sock. */
1047 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1051 /* Latch state of peer */
1052 unix_state_lock(other);
1054 /* Apparently VFS overslept socket death. Retry. */
1055 if (sock_flag(other, SOCK_DEAD)) {
1056 unix_state_unlock(other);
1061 err = -ECONNREFUSED;
1062 if (other->sk_state != TCP_LISTEN)
1064 if (other->sk_shutdown & RCV_SHUTDOWN)
1067 if (unix_recvq_full(other)) {
1072 timeo = unix_wait_for_peer(other, timeo);
1074 err = sock_intr_errno(timeo);
1075 if (signal_pending(current))
1083 It is tricky place. We need to grab write lock and cannot
1084 drop lock on peer. It is dangerous because deadlock is
1085 possible. Connect to self case and simultaneous
1086 attempt to connect are eliminated by checking socket
1087 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1088 check this before attempt to grab lock.
1090 Well, and we have to recheck the state after socket locked.
1096 /* This is ok... continue with connect */
1098 case TCP_ESTABLISHED:
1099 /* Socket is already connected */
1107 unix_state_lock_nested(sk);
1109 if (sk->sk_state != st) {
1110 unix_state_unlock(sk);
1111 unix_state_unlock(other);
1116 err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1118 unix_state_unlock(sk);
1122 /* The way is open! Fastly set all the necessary fields... */
1125 unix_peer(newsk) = sk;
1126 newsk->sk_state = TCP_ESTABLISHED;
1127 newsk->sk_type = sk->sk_type;
1128 newsk->sk_peercred.pid = task_tgid_vnr(current);
1129 newsk->sk_peercred.uid = current->euid;
1130 newsk->sk_peercred.gid = current->egid;
1131 newu = unix_sk(newsk);
1132 newsk->sk_sleep = &newu->peer_wait;
1133 otheru = unix_sk(other);
1135 /* copy address information from listening to new sock*/
1137 atomic_inc(&otheru->addr->refcnt);
1138 newu->addr = otheru->addr;
1140 if (otheru->dentry) {
1141 newu->dentry = dget(otheru->dentry);
1142 newu->mnt = mntget(otheru->mnt);
1145 /* Set credentials */
1146 sk->sk_peercred = other->sk_peercred;
1148 sock->state = SS_CONNECTED;
1149 sk->sk_state = TCP_ESTABLISHED;
1152 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1153 unix_peer(sk) = newsk;
1155 unix_state_unlock(sk);
1157 /* take ten and and send info to listening sock */
1158 spin_lock(&other->sk_receive_queue.lock);
1159 __skb_queue_tail(&other->sk_receive_queue, skb);
1160 spin_unlock(&other->sk_receive_queue.lock);
1161 unix_state_unlock(other);
1162 other->sk_data_ready(other, 0);
1168 unix_state_unlock(other);
1174 unix_release_sock(newsk, 0);
1180 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1182 struct sock *ska=socka->sk, *skb = sockb->sk;
1184 /* Join our sockets back to back */
1189 ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
1190 ska->sk_peercred.uid = skb->sk_peercred.uid = current->euid;
1191 ska->sk_peercred.gid = skb->sk_peercred.gid = current->egid;
1193 if (ska->sk_type != SOCK_DGRAM) {
1194 ska->sk_state = TCP_ESTABLISHED;
1195 skb->sk_state = TCP_ESTABLISHED;
1196 socka->state = SS_CONNECTED;
1197 sockb->state = SS_CONNECTED;
1202 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1204 struct sock *sk = sock->sk;
1206 struct sk_buff *skb;
1210 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
1214 if (sk->sk_state != TCP_LISTEN)
1217 /* If socket state is TCP_LISTEN it cannot change (for now...),
1218 * so that no locks are necessary.
1221 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1223 /* This means receive shutdown. */
1230 skb_free_datagram(sk, skb);
1231 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1233 /* attach accepted sock to socket */
1234 unix_state_lock(tsk);
1235 newsock->state = SS_CONNECTED;
1236 sock_graft(tsk, newsock);
1237 unix_state_unlock(tsk);
1245 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1247 struct sock *sk = sock->sk;
1248 struct unix_sock *u;
1249 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1253 sk = unix_peer_get(sk);
1264 unix_state_lock(sk);
1266 sunaddr->sun_family = AF_UNIX;
1267 sunaddr->sun_path[0] = 0;
1268 *uaddr_len = sizeof(short);
1270 struct unix_address *addr = u->addr;
1272 *uaddr_len = addr->len;
1273 memcpy(sunaddr, addr->name, *uaddr_len);
1275 unix_state_unlock(sk);
1281 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1285 scm->fp = UNIXCB(skb).fp;
1286 skb->destructor = sock_wfree;
1287 UNIXCB(skb).fp = NULL;
1289 for (i=scm->fp->count-1; i>=0; i--)
1290 unix_notinflight(scm->fp->fp[i]);
1293 static void unix_destruct_fds(struct sk_buff *skb)
1295 struct scm_cookie scm;
1296 memset(&scm, 0, sizeof(scm));
1297 unix_detach_fds(&scm, skb);
1299 /* Alas, it calls VFS */
1300 /* So fscking what? fput() had been SMP-safe since the last Summer */
1305 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1310 * Need to duplicate file references for the sake of garbage
1311 * collection. Otherwise a socket in the fps might become a
1312 * candidate for GC while the skb is not yet queued.
1314 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1315 if (!UNIXCB(skb).fp)
1318 for (i=scm->fp->count-1; i>=0; i--)
1319 unix_inflight(scm->fp->fp[i]);
1320 skb->destructor = unix_destruct_fds;
1325 * Send AF_UNIX data.
1328 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1329 struct msghdr *msg, size_t len)
1331 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1332 struct sock *sk = sock->sk;
1333 struct net *net = sock_net(sk);
1334 struct unix_sock *u = unix_sk(sk);
1335 struct sockaddr_un *sunaddr=msg->msg_name;
1336 struct sock *other = NULL;
1337 int namelen = 0; /* fake GCC */
1340 struct sk_buff *skb;
1342 struct scm_cookie tmp_scm;
1344 if (NULL == siocb->scm)
1345 siocb->scm = &tmp_scm;
1347 err = scm_send(sock, msg, siocb->scm);
1352 if (msg->msg_flags&MSG_OOB)
1355 if (msg->msg_namelen) {
1356 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1363 other = unix_peer_get(sk);
1368 if (test_bit(SOCK_PASSCRED, &sock->flags)
1369 && !u->addr && (err = unix_autobind(sock)) != 0)
1373 if (len > sk->sk_sndbuf - 32)
1376 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1380 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1381 if (siocb->scm->fp) {
1382 err = unix_attach_fds(siocb->scm, skb);
1386 unix_get_secdata(siocb->scm, skb);
1388 skb_reset_transport_header(skb);
1389 err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
1393 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1398 if (sunaddr == NULL)
1401 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1407 unix_state_lock(other);
1409 if (!unix_may_send(sk, other))
1412 if (sock_flag(other, SOCK_DEAD)) {
1414 * Check with 1003.1g - what should
1417 unix_state_unlock(other);
1421 unix_state_lock(sk);
1422 if (unix_peer(sk) == other) {
1424 unix_state_unlock(sk);
1426 unix_dgram_disconnected(sk, other);
1428 err = -ECONNREFUSED;
1430 unix_state_unlock(sk);
1440 if (other->sk_shutdown & RCV_SHUTDOWN)
1443 if (sk->sk_type != SOCK_SEQPACKET) {
1444 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1449 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1455 timeo = unix_wait_for_peer(other, timeo);
1457 err = sock_intr_errno(timeo);
1458 if (signal_pending(current))
1464 skb_queue_tail(&other->sk_receive_queue, skb);
1465 unix_state_unlock(other);
1466 other->sk_data_ready(other, len);
1468 scm_destroy(siocb->scm);
1472 unix_state_unlock(other);
1478 scm_destroy(siocb->scm);
1483 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1484 struct msghdr *msg, size_t len)
1486 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1487 struct sock *sk = sock->sk;
1488 struct sock *other = NULL;
1489 struct sockaddr_un *sunaddr=msg->msg_name;
1491 struct sk_buff *skb;
1493 struct scm_cookie tmp_scm;
1494 bool fds_sent = false;
1496 if (NULL == siocb->scm)
1497 siocb->scm = &tmp_scm;
1499 err = scm_send(sock, msg, siocb->scm);
1504 if (msg->msg_flags&MSG_OOB)
1507 if (msg->msg_namelen) {
1508 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1513 other = unix_peer(sk);
1518 if (sk->sk_shutdown & SEND_SHUTDOWN)
1524 * Optimisation for the fact that under 0.01% of X
1525 * messages typically need breaking up.
1530 /* Keep two messages in the pipe so it schedules better */
1531 if (size > ((sk->sk_sndbuf >> 1) - 64))
1532 size = (sk->sk_sndbuf >> 1) - 64;
1534 if (size > SKB_MAX_ALLOC)
1535 size = SKB_MAX_ALLOC;
1541 skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err);
1547 * If you pass two values to the sock_alloc_send_skb
1548 * it tries to grab the large buffer with GFP_NOFS
1549 * (which can fail easily), and if it fails grab the
1550 * fallback size buffer which is under a page and will
1553 size = min_t(int, size, skb_tailroom(skb));
1555 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1556 /* Only send the fds in the first buffer */
1557 if (siocb->scm->fp && !fds_sent) {
1558 err = unix_attach_fds(siocb->scm, skb);
1566 if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) {
1571 unix_state_lock(other);
1573 if (sock_flag(other, SOCK_DEAD) ||
1574 (other->sk_shutdown & RCV_SHUTDOWN))
1577 skb_queue_tail(&other->sk_receive_queue, skb);
1578 unix_state_unlock(other);
1579 other->sk_data_ready(other, size);
1583 scm_destroy(siocb->scm);
1589 unix_state_unlock(other);
1592 if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL))
1593 send_sig(SIGPIPE,current,0);
1596 scm_destroy(siocb->scm);
1598 return sent ? : err;
1601 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1602 struct msghdr *msg, size_t len)
1605 struct sock *sk = sock->sk;
1607 err = sock_error(sk);
1611 if (sk->sk_state != TCP_ESTABLISHED)
1614 if (msg->msg_namelen)
1615 msg->msg_namelen = 0;
1617 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1620 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1622 struct unix_sock *u = unix_sk(sk);
1624 msg->msg_namelen = 0;
1626 msg->msg_namelen = u->addr->len;
1627 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1631 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1632 struct msghdr *msg, size_t size,
1635 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1636 struct scm_cookie tmp_scm;
1637 struct sock *sk = sock->sk;
1638 struct unix_sock *u = unix_sk(sk);
1639 int noblock = flags & MSG_DONTWAIT;
1640 struct sk_buff *skb;
1647 msg->msg_namelen = 0;
1649 mutex_lock(&u->readlock);
1651 skb = skb_recv_datagram(sk, flags, noblock, &err);
1653 unix_state_lock(sk);
1654 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1655 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1656 (sk->sk_shutdown & RCV_SHUTDOWN))
1658 unix_state_unlock(sk);
1662 wake_up_interruptible_sync(&u->peer_wait);
1665 unix_copy_addr(msg, skb->sk);
1667 if (size > skb->len)
1669 else if (size < skb->len)
1670 msg->msg_flags |= MSG_TRUNC;
1672 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1677 siocb->scm = &tmp_scm;
1678 memset(&tmp_scm, 0, sizeof(tmp_scm));
1680 siocb->scm->creds = *UNIXCREDS(skb);
1681 unix_set_secdata(siocb->scm, skb);
1683 if (!(flags & MSG_PEEK))
1686 unix_detach_fds(siocb->scm, skb);
1690 /* It is questionable: on PEEK we could:
1691 - do not return fds - good, but too simple 8)
1692 - return fds, and do not return them on read (old strategy,
1694 - clone fds (I chose it for now, it is the most universal
1697 POSIX 1003.1g does not actually define this clearly
1698 at all. POSIX 1003.1g doesn't define a lot of things
1703 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1707 scm_recv(sock, msg, siocb->scm, flags);
1710 skb_free_datagram(sk,skb);
1712 mutex_unlock(&u->readlock);
1718 * Sleep until data has arrive. But check for races..
1721 static long unix_stream_data_wait(struct sock * sk, long timeo)
1725 unix_state_lock(sk);
1728 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
1730 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1732 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1733 signal_pending(current) ||
1737 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1738 unix_state_unlock(sk);
1739 timeo = schedule_timeout(timeo);
1740 unix_state_lock(sk);
1741 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1744 finish_wait(sk->sk_sleep, &wait);
1745 unix_state_unlock(sk);
1751 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1752 struct msghdr *msg, size_t size,
1755 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1756 struct scm_cookie tmp_scm;
1757 struct sock *sk = sock->sk;
1758 struct unix_sock *u = unix_sk(sk);
1759 struct sockaddr_un *sunaddr=msg->msg_name;
1761 int check_creds = 0;
1767 if (sk->sk_state != TCP_ESTABLISHED)
1774 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1775 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1777 msg->msg_namelen = 0;
1779 /* Lock the socket to prevent queue disordering
1780 * while sleeps in memcpy_tomsg
1784 siocb->scm = &tmp_scm;
1785 memset(&tmp_scm, 0, sizeof(tmp_scm));
1788 mutex_lock(&u->readlock);
1793 struct sk_buff *skb;
1795 unix_state_lock(sk);
1796 skb = skb_dequeue(&sk->sk_receive_queue);
1799 if (copied >= target)
1803 * POSIX 1003.1g mandates this order.
1806 if ((err = sock_error(sk)) != 0)
1808 if (sk->sk_shutdown & RCV_SHUTDOWN)
1811 unix_state_unlock(sk);
1815 mutex_unlock(&u->readlock);
1817 timeo = unix_stream_data_wait(sk, timeo);
1819 if (signal_pending(current)) {
1820 err = sock_intr_errno(timeo);
1823 mutex_lock(&u->readlock);
1826 unix_state_unlock(sk);
1829 unix_state_unlock(sk);
1832 /* Never glue messages from different writers */
1833 if (memcmp(UNIXCREDS(skb), &siocb->scm->creds, sizeof(siocb->scm->creds)) != 0) {
1834 skb_queue_head(&sk->sk_receive_queue, skb);
1838 /* Copy credentials */
1839 siocb->scm->creds = *UNIXCREDS(skb);
1843 /* Copy address just once */
1846 unix_copy_addr(msg, skb->sk);
1850 chunk = min_t(unsigned int, skb->len, size);
1851 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1852 skb_queue_head(&sk->sk_receive_queue, skb);
1860 /* Mark read part of skb as used */
1861 if (!(flags & MSG_PEEK))
1863 skb_pull(skb, chunk);
1866 unix_detach_fds(siocb->scm, skb);
1868 /* put the skb back if we didn't use it up.. */
1871 skb_queue_head(&sk->sk_receive_queue, skb);
1882 /* It is questionable, see note in unix_dgram_recvmsg.
1885 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1887 /* put message back and return */
1888 skb_queue_head(&sk->sk_receive_queue, skb);
1893 mutex_unlock(&u->readlock);
1894 scm_recv(sock, msg, siocb->scm, flags);
1896 return copied ? : err;
1899 static int unix_shutdown(struct socket *sock, int mode)
1901 struct sock *sk = sock->sk;
1904 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1907 unix_state_lock(sk);
1908 sk->sk_shutdown |= mode;
1909 other=unix_peer(sk);
1912 unix_state_unlock(sk);
1913 sk->sk_state_change(sk);
1916 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1920 if (mode&RCV_SHUTDOWN)
1921 peer_mode |= SEND_SHUTDOWN;
1922 if (mode&SEND_SHUTDOWN)
1923 peer_mode |= RCV_SHUTDOWN;
1924 unix_state_lock(other);
1925 other->sk_shutdown |= peer_mode;
1926 unix_state_unlock(other);
1927 other->sk_state_change(other);
1928 read_lock(&other->sk_callback_lock);
1929 if (peer_mode == SHUTDOWN_MASK)
1930 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1931 else if (peer_mode & RCV_SHUTDOWN)
1932 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
1933 read_unlock(&other->sk_callback_lock);
1941 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1943 struct sock *sk = sock->sk;
1950 amount = atomic_read(&sk->sk_wmem_alloc);
1951 err = put_user(amount, (int __user *)arg);
1955 struct sk_buff *skb;
1957 if (sk->sk_state == TCP_LISTEN) {
1962 spin_lock(&sk->sk_receive_queue.lock);
1963 if (sk->sk_type == SOCK_STREAM ||
1964 sk->sk_type == SOCK_SEQPACKET) {
1965 skb_queue_walk(&sk->sk_receive_queue, skb)
1968 skb = skb_peek(&sk->sk_receive_queue);
1972 spin_unlock(&sk->sk_receive_queue.lock);
1973 err = put_user(amount, (int __user *)arg);
1984 static unsigned int unix_poll(struct file * file, struct socket *sock, poll_table *wait)
1986 struct sock *sk = sock->sk;
1989 poll_wait(file, sk->sk_sleep, wait);
1992 /* exceptional events? */
1995 if (sk->sk_shutdown == SHUTDOWN_MASK)
1997 if (sk->sk_shutdown & RCV_SHUTDOWN)
2001 if (!skb_queue_empty(&sk->sk_receive_queue) ||
2002 (sk->sk_shutdown & RCV_SHUTDOWN))
2003 mask |= POLLIN | POLLRDNORM;
2005 /* Connection-based need to check for termination and startup */
2006 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && sk->sk_state == TCP_CLOSE)
2010 * we set writable also when the other side has shut down the
2011 * connection. This prevents stuck sockets.
2013 if (unix_writable(sk))
2014 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2019 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2022 struct sock *sk = sock->sk, *other;
2023 unsigned int mask, writable;
2025 poll_wait(file, sk->sk_sleep, wait);
2028 /* exceptional events? */
2029 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2031 if (sk->sk_shutdown & RCV_SHUTDOWN)
2033 if (sk->sk_shutdown == SHUTDOWN_MASK)
2037 if (!skb_queue_empty(&sk->sk_receive_queue) ||
2038 (sk->sk_shutdown & RCV_SHUTDOWN))
2039 mask |= POLLIN | POLLRDNORM;
2041 /* Connection-based need to check for termination and startup */
2042 if (sk->sk_type == SOCK_SEQPACKET) {
2043 if (sk->sk_state == TCP_CLOSE)
2045 /* connection hasn't started yet? */
2046 if (sk->sk_state == TCP_SYN_SENT)
2051 writable = unix_writable(sk);
2053 other = unix_peer_get(sk);
2055 if (unix_peer(other) != sk) {
2056 poll_wait(file, &unix_sk(other)->peer_wait,
2058 if (unix_recvq_full(other))
2067 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2069 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2074 #ifdef CONFIG_PROC_FS
2075 static struct sock *first_unix_socket(int *i)
2077 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2078 if (!hlist_empty(&unix_socket_table[*i]))
2079 return __sk_head(&unix_socket_table[*i]);
2084 static struct sock *next_unix_socket(int *i, struct sock *s)
2086 struct sock *next = sk_next(s);
2087 /* More in this chain? */
2090 /* Look for next non-empty chain. */
2091 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2092 if (!hlist_empty(&unix_socket_table[*i]))
2093 return __sk_head(&unix_socket_table[*i]);
2098 struct unix_iter_state {
2099 struct seq_net_private p;
2102 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2104 struct unix_iter_state *iter = seq->private;
2108 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2109 if (sock_net(s) != seq_file_net(seq))
2119 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2120 __acquires(unix_table_lock)
2122 spin_lock(&unix_table_lock);
2123 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2126 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2128 struct unix_iter_state *iter = seq->private;
2129 struct sock *sk = v;
2132 if (v == SEQ_START_TOKEN)
2133 sk = first_unix_socket(&iter->i);
2135 sk = next_unix_socket(&iter->i, sk);
2136 while (sk && (sock_net(sk) != seq_file_net(seq)))
2137 sk = next_unix_socket(&iter->i, sk);
2141 static void unix_seq_stop(struct seq_file *seq, void *v)
2142 __releases(unix_table_lock)
2144 spin_unlock(&unix_table_lock);
2147 static int unix_seq_show(struct seq_file *seq, void *v)
2150 if (v == SEQ_START_TOKEN)
2151 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2155 struct unix_sock *u = unix_sk(s);
2158 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2160 atomic_read(&s->sk_refcnt),
2162 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2165 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2166 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2174 len = u->addr->len - sizeof(short);
2175 if (!UNIX_ABSTRACT(s))
2181 for ( ; i < len; i++)
2182 seq_putc(seq, u->addr->name->sun_path[i]);
2184 unix_state_unlock(s);
2185 seq_putc(seq, '\n');
2191 static const struct seq_operations unix_seq_ops = {
2192 .start = unix_seq_start,
2193 .next = unix_seq_next,
2194 .stop = unix_seq_stop,
2195 .show = unix_seq_show,
2199 static int unix_seq_open(struct inode *inode, struct file *file)
2201 return seq_open_net(inode, file, &unix_seq_ops,
2202 sizeof(struct unix_iter_state));
2205 static const struct file_operations unix_seq_fops = {
2206 .owner = THIS_MODULE,
2207 .open = unix_seq_open,
2209 .llseek = seq_lseek,
2210 .release = seq_release_net,
2215 static struct net_proto_family unix_family_ops = {
2217 .create = unix_create,
2218 .owner = THIS_MODULE,
2222 static int unix_net_init(struct net *net)
2224 int error = -ENOMEM;
2226 net->unx.sysctl_max_dgram_qlen = 10;
2227 if (unix_sysctl_register(net))
2230 #ifdef CONFIG_PROC_FS
2231 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2232 unix_sysctl_unregister(net);
2241 static void unix_net_exit(struct net *net)
2243 unix_sysctl_unregister(net);
2244 proc_net_remove(net, "unix");
2247 static struct pernet_operations unix_net_ops = {
2248 .init = unix_net_init,
2249 .exit = unix_net_exit,
2252 static int __init af_unix_init(void)
2255 struct sk_buff *dummy_skb;
2257 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2259 rc = proto_register(&unix_proto, 1);
2261 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2266 sock_register(&unix_family_ops);
2267 register_pernet_subsys(&unix_net_ops);
2272 static void __exit af_unix_exit(void)
2274 sock_unregister(PF_UNIX);
2275 proto_unregister(&unix_proto);
2276 unregister_pernet_subsys(&unix_net_ops);
2279 /* Earlier than device_initcall() so that other drivers invoking
2280 request_module() don't end up in a loop when modprobe tries
2281 to use a UNIX socket. But later than subsys_initcall() because
2282 we depend on stuff initialised there */
2283 fs_initcall(af_unix_init);
2284 module_exit(af_unix_exit);
2286 MODULE_LICENSE("GPL");
2287 MODULE_ALIAS_NETPROTO(PF_UNIX);