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 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] 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 static inline int unix_writable(struct sock *sk)
308 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
311 static void unix_write_space(struct sock *sk)
313 struct socket_wq *wq;
316 if (unix_writable(sk)) {
317 wq = rcu_dereference(sk->sk_wq);
318 if (wq_has_sleeper(wq))
319 wake_up_interruptible_sync_poll(&wq->wait,
320 POLLOUT | POLLWRNORM | POLLWRBAND);
321 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
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(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
362 unix_release_addr(u->addr);
364 atomic_long_dec(&unix_nr_socks);
366 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
368 #ifdef UNIX_REFCNT_DEBUG
369 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
370 atomic_long_read(&unix_nr_socks));
374 static void unix_release_sock(struct sock *sk, int embrion)
376 struct unix_sock *u = unix_sk(sk);
377 struct dentry *dentry;
378 struct vfsmount *mnt;
383 unix_remove_socket(sk);
388 sk->sk_shutdown = SHUTDOWN_MASK;
393 state = sk->sk_state;
394 sk->sk_state = TCP_CLOSE;
395 unix_state_unlock(sk);
397 wake_up_interruptible_all(&u->peer_wait);
399 skpair = unix_peer(sk);
401 if (skpair != NULL) {
402 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
403 unix_state_lock(skpair);
405 skpair->sk_shutdown = SHUTDOWN_MASK;
406 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
407 skpair->sk_err = ECONNRESET;
408 unix_state_unlock(skpair);
409 skpair->sk_state_change(skpair);
410 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
412 sock_put(skpair); /* It may now die */
413 unix_peer(sk) = NULL;
416 /* Try to flush out this socket. Throw out buffers at least */
418 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
419 if (state == TCP_LISTEN)
420 unix_release_sock(skb->sk, 1);
421 /* passed fds are erased in the kfree_skb hook */
432 /* ---- Socket is dead now and most probably destroyed ---- */
435 * Fixme: BSD difference: In BSD all sockets connected to use get
436 * ECONNRESET and we die on the spot. In Linux we behave
437 * like files and pipes do and wait for the last
440 * Can't we simply set sock->err?
442 * What the above comment does talk about? --ANK(980817)
445 if (unix_tot_inflight)
446 unix_gc(); /* Garbage collect fds */
449 static void init_peercred(struct sock *sk)
451 put_pid(sk->sk_peer_pid);
452 if (sk->sk_peer_cred)
453 put_cred(sk->sk_peer_cred);
454 sk->sk_peer_pid = get_pid(task_tgid(current));
455 sk->sk_peer_cred = get_current_cred();
458 static void copy_peercred(struct sock *sk, struct sock *peersk)
460 put_pid(sk->sk_peer_pid);
461 if (sk->sk_peer_cred)
462 put_cred(sk->sk_peer_cred);
463 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
464 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
467 static int unix_listen(struct socket *sock, int backlog)
470 struct sock *sk = sock->sk;
471 struct unix_sock *u = unix_sk(sk);
472 struct pid *old_pid = NULL;
473 const struct cred *old_cred = NULL;
476 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
477 goto out; /* Only stream/seqpacket sockets accept */
480 goto out; /* No listens on an unbound socket */
482 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
484 if (backlog > sk->sk_max_ack_backlog)
485 wake_up_interruptible_all(&u->peer_wait);
486 sk->sk_max_ack_backlog = backlog;
487 sk->sk_state = TCP_LISTEN;
488 /* set credentials so connect can copy them */
493 unix_state_unlock(sk);
501 static int unix_release(struct socket *);
502 static int unix_bind(struct socket *, struct sockaddr *, int);
503 static int unix_stream_connect(struct socket *, struct sockaddr *,
504 int addr_len, int flags);
505 static int unix_socketpair(struct socket *, struct socket *);
506 static int unix_accept(struct socket *, struct socket *, int);
507 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
508 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
509 static unsigned int unix_dgram_poll(struct file *, struct socket *,
511 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
512 static int unix_shutdown(struct socket *, int);
513 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
514 struct msghdr *, size_t);
515 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
516 struct msghdr *, size_t, int);
517 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
518 struct msghdr *, size_t);
519 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
520 struct msghdr *, size_t, int);
521 static int unix_dgram_connect(struct socket *, struct sockaddr *,
523 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
524 struct msghdr *, size_t);
525 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
526 struct msghdr *, size_t, int);
528 static const struct proto_ops unix_stream_ops = {
530 .owner = THIS_MODULE,
531 .release = unix_release,
533 .connect = unix_stream_connect,
534 .socketpair = unix_socketpair,
535 .accept = unix_accept,
536 .getname = unix_getname,
539 .listen = unix_listen,
540 .shutdown = unix_shutdown,
541 .setsockopt = sock_no_setsockopt,
542 .getsockopt = sock_no_getsockopt,
543 .sendmsg = unix_stream_sendmsg,
544 .recvmsg = unix_stream_recvmsg,
545 .mmap = sock_no_mmap,
546 .sendpage = sock_no_sendpage,
549 static const struct proto_ops unix_dgram_ops = {
551 .owner = THIS_MODULE,
552 .release = unix_release,
554 .connect = unix_dgram_connect,
555 .socketpair = unix_socketpair,
556 .accept = sock_no_accept,
557 .getname = unix_getname,
558 .poll = unix_dgram_poll,
560 .listen = sock_no_listen,
561 .shutdown = unix_shutdown,
562 .setsockopt = sock_no_setsockopt,
563 .getsockopt = sock_no_getsockopt,
564 .sendmsg = unix_dgram_sendmsg,
565 .recvmsg = unix_dgram_recvmsg,
566 .mmap = sock_no_mmap,
567 .sendpage = sock_no_sendpage,
570 static const struct proto_ops unix_seqpacket_ops = {
572 .owner = THIS_MODULE,
573 .release = unix_release,
575 .connect = unix_stream_connect,
576 .socketpair = unix_socketpair,
577 .accept = unix_accept,
578 .getname = unix_getname,
579 .poll = unix_dgram_poll,
581 .listen = unix_listen,
582 .shutdown = unix_shutdown,
583 .setsockopt = sock_no_setsockopt,
584 .getsockopt = sock_no_getsockopt,
585 .sendmsg = unix_seqpacket_sendmsg,
586 .recvmsg = unix_seqpacket_recvmsg,
587 .mmap = sock_no_mmap,
588 .sendpage = sock_no_sendpage,
591 static struct proto unix_proto = {
593 .owner = THIS_MODULE,
594 .obj_size = sizeof(struct unix_sock),
598 * AF_UNIX sockets do not interact with hardware, hence they
599 * dont trigger interrupts - so it's safe for them to have
600 * bh-unsafe locking for their sk_receive_queue.lock. Split off
601 * this special lock-class by reinitializing the spinlock key:
603 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
605 static struct sock *unix_create1(struct net *net, struct socket *sock)
607 struct sock *sk = NULL;
610 atomic_long_inc(&unix_nr_socks);
611 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
614 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
618 sock_init_data(sock, sk);
619 lockdep_set_class(&sk->sk_receive_queue.lock,
620 &af_unix_sk_receive_queue_lock_key);
622 sk->sk_write_space = unix_write_space;
623 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
624 sk->sk_destruct = unix_sock_destructor;
628 spin_lock_init(&u->lock);
629 atomic_long_set(&u->inflight, 0);
630 INIT_LIST_HEAD(&u->link);
631 mutex_init(&u->readlock); /* single task reading lock */
632 init_waitqueue_head(&u->peer_wait);
633 unix_insert_socket(unix_sockets_unbound, sk);
636 atomic_long_dec(&unix_nr_socks);
639 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
645 static int unix_create(struct net *net, struct socket *sock, int protocol,
648 if (protocol && protocol != PF_UNIX)
649 return -EPROTONOSUPPORT;
651 sock->state = SS_UNCONNECTED;
653 switch (sock->type) {
655 sock->ops = &unix_stream_ops;
658 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
662 sock->type = SOCK_DGRAM;
664 sock->ops = &unix_dgram_ops;
667 sock->ops = &unix_seqpacket_ops;
670 return -ESOCKTNOSUPPORT;
673 return unix_create1(net, sock) ? 0 : -ENOMEM;
676 static int unix_release(struct socket *sock)
678 struct sock *sk = sock->sk;
683 unix_release_sock(sk, 0);
689 static int unix_autobind(struct socket *sock)
691 struct sock *sk = sock->sk;
692 struct net *net = sock_net(sk);
693 struct unix_sock *u = unix_sk(sk);
694 static u32 ordernum = 1;
695 struct unix_address *addr;
697 unsigned int retries = 0;
699 mutex_lock(&u->readlock);
706 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
710 addr->name->sun_family = AF_UNIX;
711 atomic_set(&addr->refcnt, 1);
714 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
715 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
717 spin_lock(&unix_table_lock);
718 ordernum = (ordernum+1)&0xFFFFF;
720 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
722 spin_unlock(&unix_table_lock);
724 * __unix_find_socket_byname() may take long time if many names
725 * are already in use.
728 /* Give up if all names seems to be in use. */
729 if (retries++ == 0xFFFFF) {
736 addr->hash ^= sk->sk_type;
738 __unix_remove_socket(sk);
740 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
741 spin_unlock(&unix_table_lock);
744 out: mutex_unlock(&u->readlock);
748 static struct sock *unix_find_other(struct net *net,
749 struct sockaddr_un *sunname, int len,
750 int type, unsigned hash, int *error)
756 if (sunname->sun_path[0]) {
758 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
761 inode = path.dentry->d_inode;
762 err = inode_permission(inode, MAY_WRITE);
767 if (!S_ISSOCK(inode->i_mode))
769 u = unix_find_socket_byinode(inode);
773 if (u->sk_type == type)
774 touch_atime(path.mnt, path.dentry);
779 if (u->sk_type != type) {
785 u = unix_find_socket_byname(net, sunname, len, type, hash);
787 struct dentry *dentry;
788 dentry = unix_sk(u)->dentry;
790 touch_atime(unix_sk(u)->mnt, dentry);
804 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
806 struct sock *sk = sock->sk;
807 struct net *net = sock_net(sk);
808 struct unix_sock *u = unix_sk(sk);
809 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
810 struct dentry *dentry = NULL;
814 struct unix_address *addr;
815 struct hlist_head *list;
818 if (sunaddr->sun_family != AF_UNIX)
821 if (addr_len == sizeof(short)) {
822 err = unix_autobind(sock);
826 err = unix_mkname(sunaddr, addr_len, &hash);
831 mutex_lock(&u->readlock);
838 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
842 memcpy(addr->name, sunaddr, addr_len);
843 addr->len = addr_len;
844 addr->hash = hash ^ sk->sk_type;
845 atomic_set(&addr->refcnt, 1);
847 if (sunaddr->sun_path[0]) {
851 * Get the parent directory, calculate the hash for last
854 err = kern_path_parent(sunaddr->sun_path, &nd);
856 goto out_mknod_parent;
858 dentry = lookup_create(&nd, 0);
859 err = PTR_ERR(dentry);
861 goto out_mknod_unlock;
864 * All right, let's create it.
867 (SOCK_INODE(sock)->i_mode & ~current_umask());
868 err = mnt_want_write(nd.path.mnt);
871 err = security_path_mknod(&nd.path, dentry, mode, 0);
873 goto out_mknod_drop_write;
874 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
875 out_mknod_drop_write:
876 mnt_drop_write(nd.path.mnt);
879 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
880 dput(nd.path.dentry);
881 nd.path.dentry = dentry;
883 addr->hash = UNIX_HASH_SIZE;
886 spin_lock(&unix_table_lock);
888 if (!sunaddr->sun_path[0]) {
890 if (__unix_find_socket_byname(net, sunaddr, addr_len,
891 sk->sk_type, hash)) {
892 unix_release_addr(addr);
896 list = &unix_socket_table[addr->hash];
898 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
899 u->dentry = nd.path.dentry;
900 u->mnt = nd.path.mnt;
904 __unix_remove_socket(sk);
906 __unix_insert_socket(list, sk);
909 spin_unlock(&unix_table_lock);
911 mutex_unlock(&u->readlock);
918 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
923 unix_release_addr(addr);
927 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
929 if (unlikely(sk1 == sk2) || !sk2) {
930 unix_state_lock(sk1);
934 unix_state_lock(sk1);
935 unix_state_lock_nested(sk2);
937 unix_state_lock(sk2);
938 unix_state_lock_nested(sk1);
942 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
944 if (unlikely(sk1 == sk2) || !sk2) {
945 unix_state_unlock(sk1);
948 unix_state_unlock(sk1);
949 unix_state_unlock(sk2);
952 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
955 struct sock *sk = sock->sk;
956 struct net *net = sock_net(sk);
957 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
962 if (addr->sa_family != AF_UNSPEC) {
963 err = unix_mkname(sunaddr, alen, &hash);
968 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
969 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
973 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
977 unix_state_double_lock(sk, other);
979 /* Apparently VFS overslept socket death. Retry. */
980 if (sock_flag(other, SOCK_DEAD)) {
981 unix_state_double_unlock(sk, other);
987 if (!unix_may_send(sk, other))
990 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
996 * 1003.1g breaking connected state with AF_UNSPEC
999 unix_state_double_lock(sk, other);
1003 * If it was connected, reconnect.
1005 if (unix_peer(sk)) {
1006 struct sock *old_peer = unix_peer(sk);
1007 unix_peer(sk) = other;
1008 unix_state_double_unlock(sk, other);
1010 if (other != old_peer)
1011 unix_dgram_disconnected(sk, old_peer);
1014 unix_peer(sk) = other;
1015 unix_state_double_unlock(sk, other);
1020 unix_state_double_unlock(sk, other);
1026 static long unix_wait_for_peer(struct sock *other, long timeo)
1028 struct unix_sock *u = unix_sk(other);
1032 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1034 sched = !sock_flag(other, SOCK_DEAD) &&
1035 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1036 unix_recvq_full(other);
1038 unix_state_unlock(other);
1041 timeo = schedule_timeout(timeo);
1043 finish_wait(&u->peer_wait, &wait);
1047 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1048 int addr_len, int flags)
1050 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1051 struct sock *sk = sock->sk;
1052 struct net *net = sock_net(sk);
1053 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1054 struct sock *newsk = NULL;
1055 struct sock *other = NULL;
1056 struct sk_buff *skb = NULL;
1062 err = unix_mkname(sunaddr, addr_len, &hash);
1067 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1068 (err = unix_autobind(sock)) != 0)
1071 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1073 /* First of all allocate resources.
1074 If we will make it after state is locked,
1075 we will have to recheck all again in any case.
1080 /* create new sock for complete connection */
1081 newsk = unix_create1(sock_net(sk), NULL);
1085 /* Allocate skb for sending to listening sock */
1086 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1091 /* Find listening sock. */
1092 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1096 /* Latch state of peer */
1097 unix_state_lock(other);
1099 /* Apparently VFS overslept socket death. Retry. */
1100 if (sock_flag(other, SOCK_DEAD)) {
1101 unix_state_unlock(other);
1106 err = -ECONNREFUSED;
1107 if (other->sk_state != TCP_LISTEN)
1109 if (other->sk_shutdown & RCV_SHUTDOWN)
1112 if (unix_recvq_full(other)) {
1117 timeo = unix_wait_for_peer(other, timeo);
1119 err = sock_intr_errno(timeo);
1120 if (signal_pending(current))
1128 It is tricky place. We need to grab our state lock and cannot
1129 drop lock on peer. It is dangerous because deadlock is
1130 possible. Connect to self case and simultaneous
1131 attempt to connect are eliminated by checking socket
1132 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1133 check this before attempt to grab lock.
1135 Well, and we have to recheck the state after socket locked.
1141 /* This is ok... continue with connect */
1143 case TCP_ESTABLISHED:
1144 /* Socket is already connected */
1152 unix_state_lock_nested(sk);
1154 if (sk->sk_state != st) {
1155 unix_state_unlock(sk);
1156 unix_state_unlock(other);
1161 err = security_unix_stream_connect(sk, other, newsk);
1163 unix_state_unlock(sk);
1167 /* The way is open! Fastly set all the necessary fields... */
1170 unix_peer(newsk) = sk;
1171 newsk->sk_state = TCP_ESTABLISHED;
1172 newsk->sk_type = sk->sk_type;
1173 init_peercred(newsk);
1174 newu = unix_sk(newsk);
1175 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1176 otheru = unix_sk(other);
1178 /* copy address information from listening to new sock*/
1180 atomic_inc(&otheru->addr->refcnt);
1181 newu->addr = otheru->addr;
1183 if (otheru->dentry) {
1184 newu->dentry = dget(otheru->dentry);
1185 newu->mnt = mntget(otheru->mnt);
1188 /* Set credentials */
1189 copy_peercred(sk, other);
1191 sock->state = SS_CONNECTED;
1192 sk->sk_state = TCP_ESTABLISHED;
1195 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1196 unix_peer(sk) = newsk;
1198 unix_state_unlock(sk);
1200 /* take ten and and send info to listening sock */
1201 spin_lock(&other->sk_receive_queue.lock);
1202 __skb_queue_tail(&other->sk_receive_queue, skb);
1203 spin_unlock(&other->sk_receive_queue.lock);
1204 unix_state_unlock(other);
1205 other->sk_data_ready(other, 0);
1211 unix_state_unlock(other);
1216 unix_release_sock(newsk, 0);
1222 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1224 struct sock *ska = socka->sk, *skb = sockb->sk;
1226 /* Join our sockets back to back */
1229 unix_peer(ska) = skb;
1230 unix_peer(skb) = ska;
1234 if (ska->sk_type != SOCK_DGRAM) {
1235 ska->sk_state = TCP_ESTABLISHED;
1236 skb->sk_state = TCP_ESTABLISHED;
1237 socka->state = SS_CONNECTED;
1238 sockb->state = SS_CONNECTED;
1243 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1245 struct sock *sk = sock->sk;
1247 struct sk_buff *skb;
1251 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1255 if (sk->sk_state != TCP_LISTEN)
1258 /* If socket state is TCP_LISTEN it cannot change (for now...),
1259 * so that no locks are necessary.
1262 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1264 /* This means receive shutdown. */
1271 skb_free_datagram(sk, skb);
1272 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1274 /* attach accepted sock to socket */
1275 unix_state_lock(tsk);
1276 newsock->state = SS_CONNECTED;
1277 sock_graft(tsk, newsock);
1278 unix_state_unlock(tsk);
1286 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1288 struct sock *sk = sock->sk;
1289 struct unix_sock *u;
1290 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1294 sk = unix_peer_get(sk);
1305 unix_state_lock(sk);
1307 sunaddr->sun_family = AF_UNIX;
1308 sunaddr->sun_path[0] = 0;
1309 *uaddr_len = sizeof(short);
1311 struct unix_address *addr = u->addr;
1313 *uaddr_len = addr->len;
1314 memcpy(sunaddr, addr->name, *uaddr_len);
1316 unix_state_unlock(sk);
1322 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1326 scm->fp = UNIXCB(skb).fp;
1327 UNIXCB(skb).fp = NULL;
1329 for (i = scm->fp->count-1; i >= 0; i--)
1330 unix_notinflight(scm->fp->fp[i]);
1333 static void unix_destruct_scm(struct sk_buff *skb)
1335 struct scm_cookie scm;
1336 memset(&scm, 0, sizeof(scm));
1337 scm.pid = UNIXCB(skb).pid;
1338 scm.cred = UNIXCB(skb).cred;
1340 unix_detach_fds(&scm, skb);
1342 /* Alas, it calls VFS */
1343 /* So fscking what? fput() had been SMP-safe since the last Summer */
1348 #define MAX_RECURSION_LEVEL 4
1350 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1353 unsigned char max_level = 0;
1354 int unix_sock_count = 0;
1356 for (i = scm->fp->count - 1; i >= 0; i--) {
1357 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1361 max_level = max(max_level,
1362 unix_sk(sk)->recursion_level);
1365 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1366 return -ETOOMANYREFS;
1369 * Need to duplicate file references for the sake of garbage
1370 * collection. Otherwise a socket in the fps might become a
1371 * candidate for GC while the skb is not yet queued.
1373 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1374 if (!UNIXCB(skb).fp)
1377 if (unix_sock_count) {
1378 for (i = scm->fp->count - 1; i >= 0; i--)
1379 unix_inflight(scm->fp->fp[i]);
1384 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1387 UNIXCB(skb).pid = get_pid(scm->pid);
1388 UNIXCB(skb).cred = get_cred(scm->cred);
1389 UNIXCB(skb).fp = NULL;
1390 if (scm->fp && send_fds)
1391 err = unix_attach_fds(scm, skb);
1393 skb->destructor = unix_destruct_scm;
1398 * Send AF_UNIX data.
1401 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1402 struct msghdr *msg, size_t len)
1404 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1405 struct sock *sk = sock->sk;
1406 struct net *net = sock_net(sk);
1407 struct unix_sock *u = unix_sk(sk);
1408 struct sockaddr_un *sunaddr = msg->msg_name;
1409 struct sock *other = NULL;
1410 int namelen = 0; /* fake GCC */
1413 struct sk_buff *skb;
1415 struct scm_cookie tmp_scm;
1418 if (NULL == siocb->scm)
1419 siocb->scm = &tmp_scm;
1421 err = scm_send(sock, msg, siocb->scm);
1426 if (msg->msg_flags&MSG_OOB)
1429 if (msg->msg_namelen) {
1430 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1437 other = unix_peer_get(sk);
1442 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1443 && (err = unix_autobind(sock)) != 0)
1447 if (len > sk->sk_sndbuf - 32)
1450 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1454 err = unix_scm_to_skb(siocb->scm, skb, true);
1457 max_level = err + 1;
1458 unix_get_secdata(siocb->scm, skb);
1460 skb_reset_transport_header(skb);
1461 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1465 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1470 if (sunaddr == NULL)
1473 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1479 if (sk_filter(other, skb) < 0) {
1480 /* Toss the packet but do not return any error to the sender */
1485 unix_state_lock(other);
1487 if (!unix_may_send(sk, other))
1490 if (sock_flag(other, SOCK_DEAD)) {
1492 * Check with 1003.1g - what should
1495 unix_state_unlock(other);
1499 unix_state_lock(sk);
1500 if (unix_peer(sk) == other) {
1501 unix_peer(sk) = NULL;
1502 unix_state_unlock(sk);
1504 unix_dgram_disconnected(sk, other);
1506 err = -ECONNREFUSED;
1508 unix_state_unlock(sk);
1518 if (other->sk_shutdown & RCV_SHUTDOWN)
1521 if (sk->sk_type != SOCK_SEQPACKET) {
1522 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1527 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1533 timeo = unix_wait_for_peer(other, timeo);
1535 err = sock_intr_errno(timeo);
1536 if (signal_pending(current))
1542 if (sock_flag(other, SOCK_RCVTSTAMP))
1543 __net_timestamp(skb);
1544 skb_queue_tail(&other->sk_receive_queue, skb);
1545 if (max_level > unix_sk(other)->recursion_level)
1546 unix_sk(other)->recursion_level = max_level;
1547 unix_state_unlock(other);
1548 other->sk_data_ready(other, len);
1550 scm_destroy(siocb->scm);
1554 unix_state_unlock(other);
1560 scm_destroy(siocb->scm);
1565 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1566 struct msghdr *msg, size_t len)
1568 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1569 struct sock *sk = sock->sk;
1570 struct sock *other = NULL;
1572 struct sk_buff *skb;
1574 struct scm_cookie tmp_scm;
1575 bool fds_sent = false;
1578 if (NULL == siocb->scm)
1579 siocb->scm = &tmp_scm;
1581 err = scm_send(sock, msg, siocb->scm);
1586 if (msg->msg_flags&MSG_OOB)
1589 if (msg->msg_namelen) {
1590 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1594 other = unix_peer(sk);
1599 if (sk->sk_shutdown & SEND_SHUTDOWN)
1602 while (sent < len) {
1604 * Optimisation for the fact that under 0.01% of X
1605 * messages typically need breaking up.
1610 /* Keep two messages in the pipe so it schedules better */
1611 if (size > ((sk->sk_sndbuf >> 1) - 64))
1612 size = (sk->sk_sndbuf >> 1) - 64;
1614 if (size > SKB_MAX_ALLOC)
1615 size = SKB_MAX_ALLOC;
1621 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1628 * If you pass two values to the sock_alloc_send_skb
1629 * it tries to grab the large buffer with GFP_NOFS
1630 * (which can fail easily), and if it fails grab the
1631 * fallback size buffer which is under a page and will
1634 size = min_t(int, size, skb_tailroom(skb));
1637 /* Only send the fds in the first buffer */
1638 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1643 max_level = err + 1;
1646 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1652 unix_state_lock(other);
1654 if (sock_flag(other, SOCK_DEAD) ||
1655 (other->sk_shutdown & RCV_SHUTDOWN))
1658 skb_queue_tail(&other->sk_receive_queue, skb);
1659 if (max_level > unix_sk(other)->recursion_level)
1660 unix_sk(other)->recursion_level = max_level;
1661 unix_state_unlock(other);
1662 other->sk_data_ready(other, size);
1666 scm_destroy(siocb->scm);
1672 unix_state_unlock(other);
1675 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1676 send_sig(SIGPIPE, current, 0);
1679 scm_destroy(siocb->scm);
1681 return sent ? : err;
1684 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1685 struct msghdr *msg, size_t len)
1688 struct sock *sk = sock->sk;
1690 err = sock_error(sk);
1694 if (sk->sk_state != TCP_ESTABLISHED)
1697 if (msg->msg_namelen)
1698 msg->msg_namelen = 0;
1700 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1703 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1704 struct msghdr *msg, size_t size,
1707 struct sock *sk = sock->sk;
1709 if (sk->sk_state != TCP_ESTABLISHED)
1712 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1715 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1717 struct unix_sock *u = unix_sk(sk);
1719 msg->msg_namelen = 0;
1721 msg->msg_namelen = u->addr->len;
1722 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1726 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1727 struct msghdr *msg, size_t size,
1730 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1731 struct scm_cookie tmp_scm;
1732 struct sock *sk = sock->sk;
1733 struct unix_sock *u = unix_sk(sk);
1734 int noblock = flags & MSG_DONTWAIT;
1735 struct sk_buff *skb;
1742 msg->msg_namelen = 0;
1744 err = mutex_lock_interruptible(&u->readlock);
1746 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1750 skb = skb_recv_datagram(sk, flags, noblock, &err);
1752 unix_state_lock(sk);
1753 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1754 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1755 (sk->sk_shutdown & RCV_SHUTDOWN))
1757 unix_state_unlock(sk);
1761 wake_up_interruptible_sync_poll(&u->peer_wait,
1762 POLLOUT | POLLWRNORM | POLLWRBAND);
1765 unix_copy_addr(msg, skb->sk);
1767 if (size > skb->len)
1769 else if (size < skb->len)
1770 msg->msg_flags |= MSG_TRUNC;
1772 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1776 if (sock_flag(sk, SOCK_RCVTSTAMP))
1777 __sock_recv_timestamp(msg, sk, skb);
1780 siocb->scm = &tmp_scm;
1781 memset(&tmp_scm, 0, sizeof(tmp_scm));
1783 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1784 unix_set_secdata(siocb->scm, skb);
1786 if (!(flags & MSG_PEEK)) {
1788 unix_detach_fds(siocb->scm, skb);
1790 /* It is questionable: on PEEK we could:
1791 - do not return fds - good, but too simple 8)
1792 - return fds, and do not return them on read (old strategy,
1794 - clone fds (I chose it for now, it is the most universal
1797 POSIX 1003.1g does not actually define this clearly
1798 at all. POSIX 1003.1g doesn't define a lot of things
1803 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1807 scm_recv(sock, msg, siocb->scm, flags);
1810 skb_free_datagram(sk, skb);
1812 mutex_unlock(&u->readlock);
1818 * Sleep until data has arrive. But check for races..
1821 static long unix_stream_data_wait(struct sock *sk, long timeo)
1825 unix_state_lock(sk);
1828 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1830 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1832 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1833 signal_pending(current) ||
1837 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1838 unix_state_unlock(sk);
1839 timeo = schedule_timeout(timeo);
1840 unix_state_lock(sk);
1841 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1844 finish_wait(sk_sleep(sk), &wait);
1845 unix_state_unlock(sk);
1851 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1852 struct msghdr *msg, size_t size,
1855 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1856 struct scm_cookie tmp_scm;
1857 struct sock *sk = sock->sk;
1858 struct unix_sock *u = unix_sk(sk);
1859 struct sockaddr_un *sunaddr = msg->msg_name;
1861 int check_creds = 0;
1867 if (sk->sk_state != TCP_ESTABLISHED)
1874 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1875 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1877 msg->msg_namelen = 0;
1879 /* Lock the socket to prevent queue disordering
1880 * while sleeps in memcpy_tomsg
1884 siocb->scm = &tmp_scm;
1885 memset(&tmp_scm, 0, sizeof(tmp_scm));
1888 err = mutex_lock_interruptible(&u->readlock);
1890 err = sock_intr_errno(timeo);
1896 struct sk_buff *skb;
1898 unix_state_lock(sk);
1899 skb = skb_dequeue(&sk->sk_receive_queue);
1901 unix_sk(sk)->recursion_level = 0;
1902 if (copied >= target)
1906 * POSIX 1003.1g mandates this order.
1909 err = sock_error(sk);
1912 if (sk->sk_shutdown & RCV_SHUTDOWN)
1915 unix_state_unlock(sk);
1919 mutex_unlock(&u->readlock);
1921 timeo = unix_stream_data_wait(sk, timeo);
1923 if (signal_pending(current)
1924 || mutex_lock_interruptible(&u->readlock)) {
1925 err = sock_intr_errno(timeo);
1931 unix_state_unlock(sk);
1934 unix_state_unlock(sk);
1937 /* Never glue messages from different writers */
1938 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
1939 (UNIXCB(skb).cred != siocb->scm->cred)) {
1940 skb_queue_head(&sk->sk_receive_queue, skb);
1944 /* Copy credentials */
1945 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1949 /* Copy address just once */
1951 unix_copy_addr(msg, skb->sk);
1955 chunk = min_t(unsigned int, skb->len, size);
1956 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1957 skb_queue_head(&sk->sk_receive_queue, skb);
1965 /* Mark read part of skb as used */
1966 if (!(flags & MSG_PEEK)) {
1967 skb_pull(skb, chunk);
1970 unix_detach_fds(siocb->scm, skb);
1972 /* put the skb back if we didn't use it up.. */
1974 skb_queue_head(&sk->sk_receive_queue, skb);
1983 /* It is questionable, see note in unix_dgram_recvmsg.
1986 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1988 /* put message back and return */
1989 skb_queue_head(&sk->sk_receive_queue, skb);
1994 mutex_unlock(&u->readlock);
1995 scm_recv(sock, msg, siocb->scm, flags);
1997 return copied ? : err;
2000 static int unix_shutdown(struct socket *sock, int mode)
2002 struct sock *sk = sock->sk;
2005 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
2010 unix_state_lock(sk);
2011 sk->sk_shutdown |= mode;
2012 other = unix_peer(sk);
2015 unix_state_unlock(sk);
2016 sk->sk_state_change(sk);
2019 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2023 if (mode&RCV_SHUTDOWN)
2024 peer_mode |= SEND_SHUTDOWN;
2025 if (mode&SEND_SHUTDOWN)
2026 peer_mode |= RCV_SHUTDOWN;
2027 unix_state_lock(other);
2028 other->sk_shutdown |= peer_mode;
2029 unix_state_unlock(other);
2030 other->sk_state_change(other);
2031 if (peer_mode == SHUTDOWN_MASK)
2032 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2033 else if (peer_mode & RCV_SHUTDOWN)
2034 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2042 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2044 struct sock *sk = sock->sk;
2050 amount = sk_wmem_alloc_get(sk);
2051 err = put_user(amount, (int __user *)arg);
2055 struct sk_buff *skb;
2057 if (sk->sk_state == TCP_LISTEN) {
2062 spin_lock(&sk->sk_receive_queue.lock);
2063 if (sk->sk_type == SOCK_STREAM ||
2064 sk->sk_type == SOCK_SEQPACKET) {
2065 skb_queue_walk(&sk->sk_receive_queue, skb)
2068 skb = skb_peek(&sk->sk_receive_queue);
2072 spin_unlock(&sk->sk_receive_queue.lock);
2073 err = put_user(amount, (int __user *)arg);
2084 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2086 struct sock *sk = sock->sk;
2089 sock_poll_wait(file, sk_sleep(sk), wait);
2092 /* exceptional events? */
2095 if (sk->sk_shutdown == SHUTDOWN_MASK)
2097 if (sk->sk_shutdown & RCV_SHUTDOWN)
2098 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2101 if (!skb_queue_empty(&sk->sk_receive_queue))
2102 mask |= POLLIN | POLLRDNORM;
2104 /* Connection-based need to check for termination and startup */
2105 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2106 sk->sk_state == TCP_CLOSE)
2110 * we set writable also when the other side has shut down the
2111 * connection. This prevents stuck sockets.
2113 if (unix_writable(sk))
2114 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2119 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2122 struct sock *sk = sock->sk, *other;
2123 unsigned int mask, writable;
2125 sock_poll_wait(file, sk_sleep(sk), wait);
2128 /* exceptional events? */
2129 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2131 if (sk->sk_shutdown & RCV_SHUTDOWN)
2132 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2133 if (sk->sk_shutdown == SHUTDOWN_MASK)
2137 if (!skb_queue_empty(&sk->sk_receive_queue))
2138 mask |= POLLIN | POLLRDNORM;
2140 /* Connection-based need to check for termination and startup */
2141 if (sk->sk_type == SOCK_SEQPACKET) {
2142 if (sk->sk_state == TCP_CLOSE)
2144 /* connection hasn't started yet? */
2145 if (sk->sk_state == TCP_SYN_SENT)
2149 /* No write status requested, avoid expensive OUT tests. */
2150 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2153 writable = unix_writable(sk);
2154 other = unix_peer_get(sk);
2156 if (unix_peer(other) != sk) {
2157 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2158 if (unix_recvq_full(other))
2165 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2167 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2172 #ifdef CONFIG_PROC_FS
2173 static struct sock *first_unix_socket(int *i)
2175 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2176 if (!hlist_empty(&unix_socket_table[*i]))
2177 return __sk_head(&unix_socket_table[*i]);
2182 static struct sock *next_unix_socket(int *i, struct sock *s)
2184 struct sock *next = sk_next(s);
2185 /* More in this chain? */
2188 /* Look for next non-empty chain. */
2189 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2190 if (!hlist_empty(&unix_socket_table[*i]))
2191 return __sk_head(&unix_socket_table[*i]);
2196 struct unix_iter_state {
2197 struct seq_net_private p;
2201 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2203 struct unix_iter_state *iter = seq->private;
2207 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2208 if (sock_net(s) != seq_file_net(seq))
2217 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2218 __acquires(unix_table_lock)
2220 spin_lock(&unix_table_lock);
2221 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2224 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2226 struct unix_iter_state *iter = seq->private;
2227 struct sock *sk = v;
2230 if (v == SEQ_START_TOKEN)
2231 sk = first_unix_socket(&iter->i);
2233 sk = next_unix_socket(&iter->i, sk);
2234 while (sk && (sock_net(sk) != seq_file_net(seq)))
2235 sk = next_unix_socket(&iter->i, sk);
2239 static void unix_seq_stop(struct seq_file *seq, void *v)
2240 __releases(unix_table_lock)
2242 spin_unlock(&unix_table_lock);
2245 static int unix_seq_show(struct seq_file *seq, void *v)
2248 if (v == SEQ_START_TOKEN)
2249 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2253 struct unix_sock *u = unix_sk(s);
2256 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2258 atomic_read(&s->sk_refcnt),
2260 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2263 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2264 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2272 len = u->addr->len - sizeof(short);
2273 if (!UNIX_ABSTRACT(s))
2279 for ( ; i < len; i++)
2280 seq_putc(seq, u->addr->name->sun_path[i]);
2282 unix_state_unlock(s);
2283 seq_putc(seq, '\n');
2289 static const struct seq_operations unix_seq_ops = {
2290 .start = unix_seq_start,
2291 .next = unix_seq_next,
2292 .stop = unix_seq_stop,
2293 .show = unix_seq_show,
2296 static int unix_seq_open(struct inode *inode, struct file *file)
2298 return seq_open_net(inode, file, &unix_seq_ops,
2299 sizeof(struct unix_iter_state));
2302 static const struct file_operations unix_seq_fops = {
2303 .owner = THIS_MODULE,
2304 .open = unix_seq_open,
2306 .llseek = seq_lseek,
2307 .release = seq_release_net,
2312 static const struct net_proto_family unix_family_ops = {
2314 .create = unix_create,
2315 .owner = THIS_MODULE,
2319 static int __net_init unix_net_init(struct net *net)
2321 int error = -ENOMEM;
2323 net->unx.sysctl_max_dgram_qlen = 10;
2324 if (unix_sysctl_register(net))
2327 #ifdef CONFIG_PROC_FS
2328 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2329 unix_sysctl_unregister(net);
2338 static void __net_exit unix_net_exit(struct net *net)
2340 unix_sysctl_unregister(net);
2341 proc_net_remove(net, "unix");
2344 static struct pernet_operations unix_net_ops = {
2345 .init = unix_net_init,
2346 .exit = unix_net_exit,
2349 static int __init af_unix_init(void)
2352 struct sk_buff *dummy_skb;
2354 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2356 rc = proto_register(&unix_proto, 1);
2358 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2363 sock_register(&unix_family_ops);
2364 register_pernet_subsys(&unix_net_ops);
2369 static void __exit af_unix_exit(void)
2371 sock_unregister(PF_UNIX);
2372 proto_unregister(&unix_proto);
2373 unregister_pernet_subsys(&unix_net_ops);
2376 /* Earlier than device_initcall() so that other drivers invoking
2377 request_module() don't end up in a loop when modprobe tries
2378 to use a UNIX socket. But later than subsys_initcall() because
2379 we depend on stuff initialised there */
2380 fs_initcall(af_unix_init);
2381 module_exit(af_unix_exit);
2383 MODULE_LICENSE("GPL");
2384 MODULE_ALIAS_NETPROTO(PF_UNIX);