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>
117 #include <linux/freezer.h>
119 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
120 EXPORT_SYMBOL_GPL(unix_socket_table);
121 DEFINE_SPINLOCK(unix_table_lock);
122 EXPORT_SYMBOL_GPL(unix_table_lock);
123 static atomic_long_t unix_nr_socks;
126 static struct hlist_head *unix_sockets_unbound(void *addr)
128 unsigned long hash = (unsigned long)addr;
132 hash %= UNIX_HASH_SIZE;
133 return &unix_socket_table[UNIX_HASH_SIZE + hash];
136 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
138 #ifdef CONFIG_SECURITY_NETWORK
139 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
141 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
144 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
146 scm->secid = *UNIXSID(skb);
149 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
152 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
154 #endif /* CONFIG_SECURITY_NETWORK */
157 * SMP locking strategy:
158 * hash table is protected with spinlock unix_table_lock
159 * each socket state is protected by separate spin lock.
162 static inline unsigned int unix_hash_fold(__wsum n)
164 unsigned int hash = (__force unsigned int)n;
168 return hash&(UNIX_HASH_SIZE-1);
171 #define unix_peer(sk) (unix_sk(sk)->peer)
173 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
175 return unix_peer(osk) == sk;
178 static inline int unix_may_send(struct sock *sk, struct sock *osk)
180 return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
183 static inline int unix_recvq_full(struct sock const *sk)
185 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
188 struct sock *unix_peer_get(struct sock *s)
196 unix_state_unlock(s);
199 EXPORT_SYMBOL_GPL(unix_peer_get);
201 static inline void unix_release_addr(struct unix_address *addr)
203 if (atomic_dec_and_test(&addr->refcnt))
208 * Check unix socket name:
209 * - should be not zero length.
210 * - if started by not zero, should be NULL terminated (FS object)
211 * - if started by zero, it is abstract name.
214 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
216 if (len <= sizeof(short) || len > sizeof(*sunaddr))
218 if (!sunaddr || sunaddr->sun_family != AF_UNIX)
220 if (sunaddr->sun_path[0]) {
222 * This may look like an off by one error but it is a bit more
223 * subtle. 108 is the longest valid AF_UNIX path for a binding.
224 * sun_path[108] doesn't as such exist. However in kernel space
225 * we are guaranteed that it is a valid memory location in our
226 * kernel address buffer.
228 ((char *)sunaddr)[len] = 0;
229 len = strlen(sunaddr->sun_path)+1+sizeof(short);
233 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
237 static void __unix_remove_socket(struct sock *sk)
239 sk_del_node_init(sk);
242 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
244 WARN_ON(!sk_unhashed(sk));
245 sk_add_node(sk, list);
248 static inline void unix_remove_socket(struct sock *sk)
250 spin_lock(&unix_table_lock);
251 __unix_remove_socket(sk);
252 spin_unlock(&unix_table_lock);
255 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
257 spin_lock(&unix_table_lock);
258 __unix_insert_socket(list, sk);
259 spin_unlock(&unix_table_lock);
262 static struct sock *__unix_find_socket_byname(struct net *net,
263 struct sockaddr_un *sunname,
264 int len, int type, unsigned int hash)
268 sk_for_each(s, &unix_socket_table[hash ^ type]) {
269 struct unix_sock *u = unix_sk(s);
271 if (!net_eq(sock_net(s), net))
274 if (u->addr->len == len &&
275 !memcmp(u->addr->name, sunname, len))
283 static inline struct sock *unix_find_socket_byname(struct net *net,
284 struct sockaddr_un *sunname,
290 spin_lock(&unix_table_lock);
291 s = __unix_find_socket_byname(net, sunname, len, type, hash);
294 spin_unlock(&unix_table_lock);
298 static struct sock *unix_find_socket_byinode(struct inode *i)
302 spin_lock(&unix_table_lock);
304 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
305 struct dentry *dentry = unix_sk(s)->path.dentry;
307 if (dentry && dentry->d_inode == i) {
314 spin_unlock(&unix_table_lock);
318 static inline int unix_writable(struct sock *sk)
320 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
323 static void unix_write_space(struct sock *sk)
325 struct socket_wq *wq;
328 if (unix_writable(sk)) {
329 wq = rcu_dereference(sk->sk_wq);
330 if (wq_has_sleeper(wq))
331 wake_up_interruptible_sync_poll(&wq->wait,
332 POLLOUT | POLLWRNORM | POLLWRBAND);
333 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
338 /* When dgram socket disconnects (or changes its peer), we clear its receive
339 * queue of packets arrived from previous peer. First, it allows to do
340 * flow control based only on wmem_alloc; second, sk connected to peer
341 * may receive messages only from that peer. */
342 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
344 if (!skb_queue_empty(&sk->sk_receive_queue)) {
345 skb_queue_purge(&sk->sk_receive_queue);
346 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
348 /* If one link of bidirectional dgram pipe is disconnected,
349 * we signal error. Messages are lost. Do not make this,
350 * when peer was not connected to us.
352 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
353 other->sk_err = ECONNRESET;
354 other->sk_error_report(other);
359 static void unix_sock_destructor(struct sock *sk)
361 struct unix_sock *u = unix_sk(sk);
363 skb_queue_purge(&sk->sk_receive_queue);
365 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
366 WARN_ON(!sk_unhashed(sk));
367 WARN_ON(sk->sk_socket);
368 if (!sock_flag(sk, SOCK_DEAD)) {
369 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
374 unix_release_addr(u->addr);
376 atomic_long_dec(&unix_nr_socks);
378 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
380 #ifdef UNIX_REFCNT_DEBUG
381 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
382 atomic_long_read(&unix_nr_socks));
386 static void unix_release_sock(struct sock *sk, int embrion)
388 struct unix_sock *u = unix_sk(sk);
394 unix_remove_socket(sk);
399 sk->sk_shutdown = SHUTDOWN_MASK;
401 u->path.dentry = NULL;
403 state = sk->sk_state;
404 sk->sk_state = TCP_CLOSE;
405 unix_state_unlock(sk);
407 wake_up_interruptible_all(&u->peer_wait);
409 skpair = unix_peer(sk);
411 if (skpair != NULL) {
412 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
413 unix_state_lock(skpair);
415 skpair->sk_shutdown = SHUTDOWN_MASK;
416 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
417 skpair->sk_err = ECONNRESET;
418 unix_state_unlock(skpair);
419 skpair->sk_state_change(skpair);
420 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
422 sock_put(skpair); /* It may now die */
423 unix_peer(sk) = NULL;
426 /* Try to flush out this socket. Throw out buffers at least */
428 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
429 if (state == TCP_LISTEN)
430 unix_release_sock(skb->sk, 1);
431 /* passed fds are erased in the kfree_skb hook */
440 /* ---- Socket is dead now and most probably destroyed ---- */
443 * Fixme: BSD difference: In BSD all sockets connected to us get
444 * ECONNRESET and we die on the spot. In Linux we behave
445 * like files and pipes do and wait for the last
448 * Can't we simply set sock->err?
450 * What the above comment does talk about? --ANK(980817)
453 if (unix_tot_inflight)
454 unix_gc(); /* Garbage collect fds */
457 static void init_peercred(struct sock *sk)
459 put_pid(sk->sk_peer_pid);
460 if (sk->sk_peer_cred)
461 put_cred(sk->sk_peer_cred);
462 sk->sk_peer_pid = get_pid(task_tgid(current));
463 sk->sk_peer_cred = get_current_cred();
466 static void copy_peercred(struct sock *sk, struct sock *peersk)
468 put_pid(sk->sk_peer_pid);
469 if (sk->sk_peer_cred)
470 put_cred(sk->sk_peer_cred);
471 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid);
472 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
475 static int unix_listen(struct socket *sock, int backlog)
478 struct sock *sk = sock->sk;
479 struct unix_sock *u = unix_sk(sk);
480 struct pid *old_pid = NULL;
483 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
484 goto out; /* Only stream/seqpacket sockets accept */
487 goto out; /* No listens on an unbound socket */
489 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
491 if (backlog > sk->sk_max_ack_backlog)
492 wake_up_interruptible_all(&u->peer_wait);
493 sk->sk_max_ack_backlog = backlog;
494 sk->sk_state = TCP_LISTEN;
495 /* set credentials so connect can copy them */
500 unix_state_unlock(sk);
506 static int unix_release(struct socket *);
507 static int unix_bind(struct socket *, struct sockaddr *, int);
508 static int unix_stream_connect(struct socket *, struct sockaddr *,
509 int addr_len, int flags);
510 static int unix_socketpair(struct socket *, struct socket *);
511 static int unix_accept(struct socket *, struct socket *, int);
512 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
513 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
514 static unsigned int unix_dgram_poll(struct file *, struct socket *,
516 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
517 static int unix_shutdown(struct socket *, int);
518 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
519 struct msghdr *, size_t);
520 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
521 struct msghdr *, size_t, int);
522 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
523 struct msghdr *, size_t);
524 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
525 struct msghdr *, size_t, int);
526 static int unix_dgram_connect(struct socket *, struct sockaddr *,
528 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
529 struct msghdr *, size_t);
530 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
531 struct msghdr *, size_t, int);
533 static int unix_set_peek_off(struct sock *sk, int val)
535 struct unix_sock *u = unix_sk(sk);
537 if (mutex_lock_interruptible(&u->readlock))
540 sk->sk_peek_off = val;
541 mutex_unlock(&u->readlock);
547 static const struct proto_ops unix_stream_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,
558 .listen = unix_listen,
559 .shutdown = unix_shutdown,
560 .setsockopt = sock_no_setsockopt,
561 .getsockopt = sock_no_getsockopt,
562 .sendmsg = unix_stream_sendmsg,
563 .recvmsg = unix_stream_recvmsg,
564 .mmap = sock_no_mmap,
565 .sendpage = sock_no_sendpage,
566 .set_peek_off = unix_set_peek_off,
569 static const struct proto_ops unix_dgram_ops = {
571 .owner = THIS_MODULE,
572 .release = unix_release,
574 .connect = unix_dgram_connect,
575 .socketpair = unix_socketpair,
576 .accept = sock_no_accept,
577 .getname = unix_getname,
578 .poll = unix_dgram_poll,
580 .listen = sock_no_listen,
581 .shutdown = unix_shutdown,
582 .setsockopt = sock_no_setsockopt,
583 .getsockopt = sock_no_getsockopt,
584 .sendmsg = unix_dgram_sendmsg,
585 .recvmsg = unix_dgram_recvmsg,
586 .mmap = sock_no_mmap,
587 .sendpage = sock_no_sendpage,
588 .set_peek_off = unix_set_peek_off,
591 static const struct proto_ops unix_seqpacket_ops = {
593 .owner = THIS_MODULE,
594 .release = unix_release,
596 .connect = unix_stream_connect,
597 .socketpair = unix_socketpair,
598 .accept = unix_accept,
599 .getname = unix_getname,
600 .poll = unix_dgram_poll,
602 .listen = unix_listen,
603 .shutdown = unix_shutdown,
604 .setsockopt = sock_no_setsockopt,
605 .getsockopt = sock_no_getsockopt,
606 .sendmsg = unix_seqpacket_sendmsg,
607 .recvmsg = unix_seqpacket_recvmsg,
608 .mmap = sock_no_mmap,
609 .sendpage = sock_no_sendpage,
610 .set_peek_off = unix_set_peek_off,
613 static struct proto unix_proto = {
615 .owner = THIS_MODULE,
616 .obj_size = sizeof(struct unix_sock),
620 * AF_UNIX sockets do not interact with hardware, hence they
621 * dont trigger interrupts - so it's safe for them to have
622 * bh-unsafe locking for their sk_receive_queue.lock. Split off
623 * this special lock-class by reinitializing the spinlock key:
625 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
627 static struct sock *unix_create1(struct net *net, struct socket *sock)
629 struct sock *sk = NULL;
632 atomic_long_inc(&unix_nr_socks);
633 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
636 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
640 sock_init_data(sock, sk);
641 lockdep_set_class(&sk->sk_receive_queue.lock,
642 &af_unix_sk_receive_queue_lock_key);
644 sk->sk_write_space = unix_write_space;
645 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
646 sk->sk_destruct = unix_sock_destructor;
648 u->path.dentry = NULL;
650 spin_lock_init(&u->lock);
651 atomic_long_set(&u->inflight, 0);
652 INIT_LIST_HEAD(&u->link);
653 mutex_init(&u->readlock); /* single task reading lock */
654 init_waitqueue_head(&u->peer_wait);
655 unix_insert_socket(unix_sockets_unbound(sk), sk);
658 atomic_long_dec(&unix_nr_socks);
661 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
667 static int unix_create(struct net *net, struct socket *sock, int protocol,
670 if (protocol && protocol != PF_UNIX)
671 return -EPROTONOSUPPORT;
673 sock->state = SS_UNCONNECTED;
675 switch (sock->type) {
677 sock->ops = &unix_stream_ops;
680 * Believe it or not BSD has AF_UNIX, SOCK_RAW though
684 sock->type = SOCK_DGRAM;
686 sock->ops = &unix_dgram_ops;
689 sock->ops = &unix_seqpacket_ops;
692 return -ESOCKTNOSUPPORT;
695 return unix_create1(net, sock) ? 0 : -ENOMEM;
698 static int unix_release(struct socket *sock)
700 struct sock *sk = sock->sk;
705 unix_release_sock(sk, 0);
711 static int unix_autobind(struct socket *sock)
713 struct sock *sk = sock->sk;
714 struct net *net = sock_net(sk);
715 struct unix_sock *u = unix_sk(sk);
716 static u32 ordernum = 1;
717 struct unix_address *addr;
719 unsigned int retries = 0;
721 err = mutex_lock_interruptible(&u->readlock);
730 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
734 addr->name->sun_family = AF_UNIX;
735 atomic_set(&addr->refcnt, 1);
738 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
739 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
741 spin_lock(&unix_table_lock);
742 ordernum = (ordernum+1)&0xFFFFF;
744 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
746 spin_unlock(&unix_table_lock);
748 * __unix_find_socket_byname() may take long time if many names
749 * are already in use.
752 /* Give up if all names seems to be in use. */
753 if (retries++ == 0xFFFFF) {
760 addr->hash ^= sk->sk_type;
762 __unix_remove_socket(sk);
764 __unix_insert_socket(&unix_socket_table[addr->hash], sk);
765 spin_unlock(&unix_table_lock);
768 out: mutex_unlock(&u->readlock);
772 static struct sock *unix_find_other(struct net *net,
773 struct sockaddr_un *sunname, int len,
774 int type, unsigned int hash, int *error)
780 if (sunname->sun_path[0]) {
782 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
785 inode = path.dentry->d_inode;
786 err = inode_permission(inode, MAY_WRITE);
791 if (!S_ISSOCK(inode->i_mode))
793 u = unix_find_socket_byinode(inode);
797 if (u->sk_type == type)
803 if (u->sk_type != type) {
809 u = unix_find_socket_byname(net, sunname, len, type, hash);
811 struct dentry *dentry;
812 dentry = unix_sk(u)->path.dentry;
814 touch_atime(&unix_sk(u)->path);
827 static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
829 struct dentry *dentry;
833 * Get the parent directory, calculate the hash for last
836 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
837 err = PTR_ERR(dentry);
842 * All right, let's create it.
844 err = security_path_mknod(&path, dentry, mode, 0);
846 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
848 res->mnt = mntget(path.mnt);
849 res->dentry = dget(dentry);
852 done_path_create(&path, dentry);
856 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
858 struct sock *sk = sock->sk;
859 struct net *net = sock_net(sk);
860 struct unix_sock *u = unix_sk(sk);
861 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
862 char *sun_path = sunaddr->sun_path;
865 struct unix_address *addr;
866 struct hlist_head *list;
869 if (sunaddr->sun_family != AF_UNIX)
872 if (addr_len == sizeof(short)) {
873 err = unix_autobind(sock);
877 err = unix_mkname(sunaddr, addr_len, &hash);
882 err = mutex_lock_interruptible(&u->readlock);
891 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
895 memcpy(addr->name, sunaddr, addr_len);
896 addr->len = addr_len;
897 addr->hash = hash ^ sk->sk_type;
898 atomic_set(&addr->refcnt, 1);
902 umode_t mode = S_IFSOCK |
903 (SOCK_INODE(sock)->i_mode & ~current_umask());
904 err = unix_mknod(sun_path, mode, &path);
908 unix_release_addr(addr);
911 addr->hash = UNIX_HASH_SIZE;
912 hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1);
913 spin_lock(&unix_table_lock);
915 list = &unix_socket_table[hash];
917 spin_lock(&unix_table_lock);
919 if (__unix_find_socket_byname(net, sunaddr, addr_len,
920 sk->sk_type, hash)) {
921 unix_release_addr(addr);
925 list = &unix_socket_table[addr->hash];
929 __unix_remove_socket(sk);
931 __unix_insert_socket(list, sk);
934 spin_unlock(&unix_table_lock);
936 mutex_unlock(&u->readlock);
941 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
943 if (unlikely(sk1 == sk2) || !sk2) {
944 unix_state_lock(sk1);
948 unix_state_lock(sk1);
949 unix_state_lock_nested(sk2);
951 unix_state_lock(sk2);
952 unix_state_lock_nested(sk1);
956 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
958 if (unlikely(sk1 == sk2) || !sk2) {
959 unix_state_unlock(sk1);
962 unix_state_unlock(sk1);
963 unix_state_unlock(sk2);
966 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
969 struct sock *sk = sock->sk;
970 struct net *net = sock_net(sk);
971 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
976 if (addr->sa_family != AF_UNSPEC) {
977 err = unix_mkname(sunaddr, alen, &hash);
982 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
983 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
987 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
991 unix_state_double_lock(sk, other);
993 /* Apparently VFS overslept socket death. Retry. */
994 if (sock_flag(other, SOCK_DEAD)) {
995 unix_state_double_unlock(sk, other);
1001 if (!unix_may_send(sk, other))
1004 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1010 * 1003.1g breaking connected state with AF_UNSPEC
1013 unix_state_double_lock(sk, other);
1017 * If it was connected, reconnect.
1019 if (unix_peer(sk)) {
1020 struct sock *old_peer = unix_peer(sk);
1021 unix_peer(sk) = other;
1022 unix_state_double_unlock(sk, other);
1024 if (other != old_peer)
1025 unix_dgram_disconnected(sk, old_peer);
1028 unix_peer(sk) = other;
1029 unix_state_double_unlock(sk, other);
1034 unix_state_double_unlock(sk, other);
1040 static long unix_wait_for_peer(struct sock *other, long timeo)
1042 struct unix_sock *u = unix_sk(other);
1046 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1048 sched = !sock_flag(other, SOCK_DEAD) &&
1049 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1050 unix_recvq_full(other);
1052 unix_state_unlock(other);
1055 timeo = schedule_timeout(timeo);
1057 finish_wait(&u->peer_wait, &wait);
1061 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1062 int addr_len, int flags)
1064 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1065 struct sock *sk = sock->sk;
1066 struct net *net = sock_net(sk);
1067 struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1068 struct sock *newsk = NULL;
1069 struct sock *other = NULL;
1070 struct sk_buff *skb = NULL;
1076 err = unix_mkname(sunaddr, addr_len, &hash);
1081 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1082 (err = unix_autobind(sock)) != 0)
1085 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1087 /* First of all allocate resources.
1088 If we will make it after state is locked,
1089 we will have to recheck all again in any case.
1094 /* create new sock for complete connection */
1095 newsk = unix_create1(sock_net(sk), NULL);
1099 /* Allocate skb for sending to listening sock */
1100 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1105 /* Find listening sock. */
1106 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1110 /* Latch state of peer */
1111 unix_state_lock(other);
1113 /* Apparently VFS overslept socket death. Retry. */
1114 if (sock_flag(other, SOCK_DEAD)) {
1115 unix_state_unlock(other);
1120 err = -ECONNREFUSED;
1121 if (other->sk_state != TCP_LISTEN)
1123 if (other->sk_shutdown & RCV_SHUTDOWN)
1126 if (unix_recvq_full(other)) {
1131 timeo = unix_wait_for_peer(other, timeo);
1133 err = sock_intr_errno(timeo);
1134 if (signal_pending(current))
1142 It is tricky place. We need to grab our state lock and cannot
1143 drop lock on peer. It is dangerous because deadlock is
1144 possible. Connect to self case and simultaneous
1145 attempt to connect are eliminated by checking socket
1146 state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1147 check this before attempt to grab lock.
1149 Well, and we have to recheck the state after socket locked.
1155 /* This is ok... continue with connect */
1157 case TCP_ESTABLISHED:
1158 /* Socket is already connected */
1166 unix_state_lock_nested(sk);
1168 if (sk->sk_state != st) {
1169 unix_state_unlock(sk);
1170 unix_state_unlock(other);
1175 err = security_unix_stream_connect(sk, other, newsk);
1177 unix_state_unlock(sk);
1181 /* The way is open! Fastly set all the necessary fields... */
1184 unix_peer(newsk) = sk;
1185 newsk->sk_state = TCP_ESTABLISHED;
1186 newsk->sk_type = sk->sk_type;
1187 init_peercred(newsk);
1188 newu = unix_sk(newsk);
1189 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1190 otheru = unix_sk(other);
1192 /* copy address information from listening to new sock*/
1194 atomic_inc(&otheru->addr->refcnt);
1195 newu->addr = otheru->addr;
1197 if (otheru->path.dentry) {
1198 path_get(&otheru->path);
1199 newu->path = otheru->path;
1202 /* Set credentials */
1203 copy_peercred(sk, other);
1205 sock->state = SS_CONNECTED;
1206 sk->sk_state = TCP_ESTABLISHED;
1209 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */
1210 unix_peer(sk) = newsk;
1212 unix_state_unlock(sk);
1214 /* take ten and and send info to listening sock */
1215 spin_lock(&other->sk_receive_queue.lock);
1216 __skb_queue_tail(&other->sk_receive_queue, skb);
1217 spin_unlock(&other->sk_receive_queue.lock);
1218 unix_state_unlock(other);
1219 other->sk_data_ready(other, 0);
1225 unix_state_unlock(other);
1230 unix_release_sock(newsk, 0);
1236 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1238 struct sock *ska = socka->sk, *skb = sockb->sk;
1240 /* Join our sockets back to back */
1243 unix_peer(ska) = skb;
1244 unix_peer(skb) = ska;
1248 if (ska->sk_type != SOCK_DGRAM) {
1249 ska->sk_state = TCP_ESTABLISHED;
1250 skb->sk_state = TCP_ESTABLISHED;
1251 socka->state = SS_CONNECTED;
1252 sockb->state = SS_CONNECTED;
1257 static void unix_sock_inherit_flags(const struct socket *old,
1260 if (test_bit(SOCK_PASSCRED, &old->flags))
1261 set_bit(SOCK_PASSCRED, &new->flags);
1262 if (test_bit(SOCK_PASSSEC, &old->flags))
1263 set_bit(SOCK_PASSSEC, &new->flags);
1266 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1268 struct sock *sk = sock->sk;
1270 struct sk_buff *skb;
1274 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1278 if (sk->sk_state != TCP_LISTEN)
1281 /* If socket state is TCP_LISTEN it cannot change (for now...),
1282 * so that no locks are necessary.
1285 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1287 /* This means receive shutdown. */
1294 skb_free_datagram(sk, skb);
1295 wake_up_interruptible(&unix_sk(sk)->peer_wait);
1297 /* attach accepted sock to socket */
1298 unix_state_lock(tsk);
1299 newsock->state = SS_CONNECTED;
1300 unix_sock_inherit_flags(sock, newsock);
1301 sock_graft(tsk, newsock);
1302 unix_state_unlock(tsk);
1310 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1312 struct sock *sk = sock->sk;
1313 struct unix_sock *u;
1314 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1318 sk = unix_peer_get(sk);
1329 unix_state_lock(sk);
1331 sunaddr->sun_family = AF_UNIX;
1332 sunaddr->sun_path[0] = 0;
1333 *uaddr_len = sizeof(short);
1335 struct unix_address *addr = u->addr;
1337 *uaddr_len = addr->len;
1338 memcpy(sunaddr, addr->name, *uaddr_len);
1340 unix_state_unlock(sk);
1346 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1350 scm->fp = UNIXCB(skb).fp;
1351 UNIXCB(skb).fp = NULL;
1353 for (i = scm->fp->count-1; i >= 0; i--)
1354 unix_notinflight(scm->fp->fp[i]);
1357 static void unix_destruct_scm(struct sk_buff *skb)
1359 struct scm_cookie scm;
1360 memset(&scm, 0, sizeof(scm));
1361 scm.pid = UNIXCB(skb).pid;
1363 unix_detach_fds(&scm, skb);
1365 /* Alas, it calls VFS */
1366 /* So fscking what? fput() had been SMP-safe since the last Summer */
1371 #define MAX_RECURSION_LEVEL 4
1373 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1376 unsigned char max_level = 0;
1377 int unix_sock_count = 0;
1379 for (i = scm->fp->count - 1; i >= 0; i--) {
1380 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1384 max_level = max(max_level,
1385 unix_sk(sk)->recursion_level);
1388 if (unlikely(max_level > MAX_RECURSION_LEVEL))
1389 return -ETOOMANYREFS;
1392 * Need to duplicate file references for the sake of garbage
1393 * collection. Otherwise a socket in the fps might become a
1394 * candidate for GC while the skb is not yet queued.
1396 UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1397 if (!UNIXCB(skb).fp)
1400 if (unix_sock_count) {
1401 for (i = scm->fp->count - 1; i >= 0; i--)
1402 unix_inflight(scm->fp->fp[i]);
1407 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1411 UNIXCB(skb).pid = get_pid(scm->pid);
1412 UNIXCB(skb).uid = scm->creds.uid;
1413 UNIXCB(skb).gid = scm->creds.gid;
1414 UNIXCB(skb).fp = NULL;
1415 if (scm->fp && send_fds)
1416 err = unix_attach_fds(scm, skb);
1418 skb->destructor = unix_destruct_scm;
1423 * Some apps rely on write() giving SCM_CREDENTIALS
1424 * We include credentials if source or destination socket
1425 * asserted SOCK_PASSCRED.
1427 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1428 const struct sock *other)
1430 if (UNIXCB(skb).pid)
1432 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1433 !other->sk_socket ||
1434 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1435 UNIXCB(skb).pid = get_pid(task_tgid(current));
1436 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1441 * Send AF_UNIX data.
1444 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1445 struct msghdr *msg, size_t len)
1447 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1448 struct sock *sk = sock->sk;
1449 struct net *net = sock_net(sk);
1450 struct unix_sock *u = unix_sk(sk);
1451 struct sockaddr_un *sunaddr = msg->msg_name;
1452 struct sock *other = NULL;
1453 int namelen = 0; /* fake GCC */
1456 struct sk_buff *skb;
1458 struct scm_cookie tmp_scm;
1462 if (NULL == siocb->scm)
1463 siocb->scm = &tmp_scm;
1465 err = scm_send(sock, msg, siocb->scm, false);
1470 if (msg->msg_flags&MSG_OOB)
1473 if (msg->msg_namelen) {
1474 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1481 other = unix_peer_get(sk);
1486 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1487 && (err = unix_autobind(sock)) != 0)
1491 if (len > sk->sk_sndbuf - 32)
1494 if (len > SKB_MAX_ALLOC)
1495 data_len = min_t(size_t,
1496 len - SKB_MAX_ALLOC,
1497 MAX_SKB_FRAGS * PAGE_SIZE);
1499 skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1500 msg->msg_flags & MSG_DONTWAIT, &err);
1504 err = unix_scm_to_skb(siocb->scm, skb, true);
1507 max_level = err + 1;
1508 unix_get_secdata(siocb->scm, skb);
1510 skb_put(skb, len - data_len);
1511 skb->data_len = data_len;
1513 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len);
1517 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1522 if (sunaddr == NULL)
1525 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1531 if (sk_filter(other, skb) < 0) {
1532 /* Toss the packet but do not return any error to the sender */
1537 unix_state_lock(other);
1539 if (!unix_may_send(sk, other))
1542 if (sock_flag(other, SOCK_DEAD)) {
1544 * Check with 1003.1g - what should
1547 unix_state_unlock(other);
1551 unix_state_lock(sk);
1552 if (unix_peer(sk) == other) {
1553 unix_peer(sk) = NULL;
1554 unix_state_unlock(sk);
1556 unix_dgram_disconnected(sk, other);
1558 err = -ECONNREFUSED;
1560 unix_state_unlock(sk);
1570 if (other->sk_shutdown & RCV_SHUTDOWN)
1573 if (sk->sk_type != SOCK_SEQPACKET) {
1574 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1579 if (unix_peer(other) != sk && unix_recvq_full(other)) {
1585 timeo = unix_wait_for_peer(other, timeo);
1587 err = sock_intr_errno(timeo);
1588 if (signal_pending(current))
1594 if (sock_flag(other, SOCK_RCVTSTAMP))
1595 __net_timestamp(skb);
1596 maybe_add_creds(skb, sock, other);
1597 skb_queue_tail(&other->sk_receive_queue, skb);
1598 if (max_level > unix_sk(other)->recursion_level)
1599 unix_sk(other)->recursion_level = max_level;
1600 unix_state_unlock(other);
1601 other->sk_data_ready(other, len);
1603 scm_destroy(siocb->scm);
1607 unix_state_unlock(other);
1613 scm_destroy(siocb->scm);
1618 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1619 struct msghdr *msg, size_t len)
1621 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1622 struct sock *sk = sock->sk;
1623 struct sock *other = NULL;
1625 struct sk_buff *skb;
1627 struct scm_cookie tmp_scm;
1628 bool fds_sent = false;
1631 if (NULL == siocb->scm)
1632 siocb->scm = &tmp_scm;
1634 err = scm_send(sock, msg, siocb->scm, false);
1639 if (msg->msg_flags&MSG_OOB)
1642 if (msg->msg_namelen) {
1643 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1647 other = unix_peer(sk);
1652 if (sk->sk_shutdown & SEND_SHUTDOWN)
1655 while (sent < len) {
1657 * Optimisation for the fact that under 0.01% of X
1658 * messages typically need breaking up.
1663 /* Keep two messages in the pipe so it schedules better */
1664 if (size > ((sk->sk_sndbuf >> 1) - 64))
1665 size = (sk->sk_sndbuf >> 1) - 64;
1667 if (size > SKB_MAX_ALLOC)
1668 size = SKB_MAX_ALLOC;
1674 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1681 * If you pass two values to the sock_alloc_send_skb
1682 * it tries to grab the large buffer with GFP_NOFS
1683 * (which can fail easily), and if it fails grab the
1684 * fallback size buffer which is under a page and will
1687 size = min_t(int, size, skb_tailroom(skb));
1690 /* Only send the fds in the first buffer */
1691 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1696 max_level = err + 1;
1699 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1705 unix_state_lock(other);
1707 if (sock_flag(other, SOCK_DEAD) ||
1708 (other->sk_shutdown & RCV_SHUTDOWN))
1711 maybe_add_creds(skb, sock, other);
1712 skb_queue_tail(&other->sk_receive_queue, skb);
1713 if (max_level > unix_sk(other)->recursion_level)
1714 unix_sk(other)->recursion_level = max_level;
1715 unix_state_unlock(other);
1716 other->sk_data_ready(other, size);
1720 scm_destroy(siocb->scm);
1726 unix_state_unlock(other);
1729 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1730 send_sig(SIGPIPE, current, 0);
1733 scm_destroy(siocb->scm);
1735 return sent ? : err;
1738 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1739 struct msghdr *msg, size_t len)
1742 struct sock *sk = sock->sk;
1744 err = sock_error(sk);
1748 if (sk->sk_state != TCP_ESTABLISHED)
1751 if (msg->msg_namelen)
1752 msg->msg_namelen = 0;
1754 return unix_dgram_sendmsg(kiocb, sock, msg, len);
1757 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
1758 struct msghdr *msg, size_t size,
1761 struct sock *sk = sock->sk;
1763 if (sk->sk_state != TCP_ESTABLISHED)
1766 return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
1769 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1771 struct unix_sock *u = unix_sk(sk);
1774 msg->msg_namelen = u->addr->len;
1775 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1779 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1780 struct msghdr *msg, size_t size,
1783 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1784 struct scm_cookie tmp_scm;
1785 struct sock *sk = sock->sk;
1786 struct unix_sock *u = unix_sk(sk);
1787 int noblock = flags & MSG_DONTWAIT;
1788 struct sk_buff *skb;
1796 err = mutex_lock_interruptible(&u->readlock);
1798 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1802 skip = sk_peek_offset(sk, flags);
1804 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1806 unix_state_lock(sk);
1807 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1808 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1809 (sk->sk_shutdown & RCV_SHUTDOWN))
1811 unix_state_unlock(sk);
1815 wake_up_interruptible_sync_poll(&u->peer_wait,
1816 POLLOUT | POLLWRNORM | POLLWRBAND);
1819 unix_copy_addr(msg, skb->sk);
1821 if (size > skb->len - skip)
1822 size = skb->len - skip;
1823 else if (size < skb->len - skip)
1824 msg->msg_flags |= MSG_TRUNC;
1826 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
1830 if (sock_flag(sk, SOCK_RCVTSTAMP))
1831 __sock_recv_timestamp(msg, sk, skb);
1834 siocb->scm = &tmp_scm;
1835 memset(&tmp_scm, 0, sizeof(tmp_scm));
1837 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
1838 unix_set_secdata(siocb->scm, skb);
1840 if (!(flags & MSG_PEEK)) {
1842 unix_detach_fds(siocb->scm, skb);
1844 sk_peek_offset_bwd(sk, skb->len);
1846 /* It is questionable: on PEEK we could:
1847 - do not return fds - good, but too simple 8)
1848 - return fds, and do not return them on read (old strategy,
1850 - clone fds (I chose it for now, it is the most universal
1853 POSIX 1003.1g does not actually define this clearly
1854 at all. POSIX 1003.1g doesn't define a lot of things
1859 sk_peek_offset_fwd(sk, size);
1862 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1864 err = (flags & MSG_TRUNC) ? skb->len - skip : size;
1866 scm_recv(sock, msg, siocb->scm, flags);
1869 skb_free_datagram(sk, skb);
1871 mutex_unlock(&u->readlock);
1877 * Sleep until more data has arrived. But check for races..
1879 static long unix_stream_data_wait(struct sock *sk, long timeo,
1880 struct sk_buff *last)
1884 unix_state_lock(sk);
1887 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1889 if (skb_peek_tail(&sk->sk_receive_queue) != last ||
1891 (sk->sk_shutdown & RCV_SHUTDOWN) ||
1892 signal_pending(current) ||
1896 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1897 unix_state_unlock(sk);
1898 timeo = freezable_schedule_timeout(timeo);
1899 unix_state_lock(sk);
1900 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1903 finish_wait(sk_sleep(sk), &wait);
1904 unix_state_unlock(sk);
1908 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1909 struct msghdr *msg, size_t size,
1912 struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1913 struct scm_cookie tmp_scm;
1914 struct sock *sk = sock->sk;
1915 struct unix_sock *u = unix_sk(sk);
1916 struct sockaddr_un *sunaddr = msg->msg_name;
1918 int check_creds = 0;
1925 if (sk->sk_state != TCP_ESTABLISHED)
1932 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1933 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1935 /* Lock the socket to prevent queue disordering
1936 * while sleeps in memcpy_tomsg
1940 siocb->scm = &tmp_scm;
1941 memset(&tmp_scm, 0, sizeof(tmp_scm));
1944 err = mutex_lock_interruptible(&u->readlock);
1946 err = sock_intr_errno(timeo);
1952 struct sk_buff *skb, *last;
1954 unix_state_lock(sk);
1955 last = skb = skb_peek(&sk->sk_receive_queue);
1958 unix_sk(sk)->recursion_level = 0;
1959 if (copied >= target)
1963 * POSIX 1003.1g mandates this order.
1966 err = sock_error(sk);
1969 if (sk->sk_shutdown & RCV_SHUTDOWN)
1972 unix_state_unlock(sk);
1976 mutex_unlock(&u->readlock);
1978 timeo = unix_stream_data_wait(sk, timeo, last);
1980 if (signal_pending(current)
1981 || mutex_lock_interruptible(&u->readlock)) {
1982 err = sock_intr_errno(timeo);
1988 unix_state_unlock(sk);
1992 skip = sk_peek_offset(sk, flags);
1993 while (skip >= skb->len) {
1996 skb = skb_peek_next(skb, &sk->sk_receive_queue);
2001 unix_state_unlock(sk);
2004 /* Never glue messages from different writers */
2005 if ((UNIXCB(skb).pid != siocb->scm->pid) ||
2006 !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
2007 !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
2009 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2010 /* Copy credentials */
2011 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2015 /* Copy address just once */
2017 unix_copy_addr(msg, skb->sk);
2021 chunk = min_t(unsigned int, skb->len - skip, size);
2022 if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) {
2030 /* Mark read part of skb as used */
2031 if (!(flags & MSG_PEEK)) {
2032 skb_pull(skb, chunk);
2034 sk_peek_offset_bwd(sk, chunk);
2037 unix_detach_fds(siocb->scm, skb);
2042 skb_unlink(skb, &sk->sk_receive_queue);
2048 /* It is questionable, see note in unix_dgram_recvmsg.
2051 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
2053 sk_peek_offset_fwd(sk, chunk);
2059 mutex_unlock(&u->readlock);
2060 scm_recv(sock, msg, siocb->scm, flags);
2062 return copied ? : err;
2065 static int unix_shutdown(struct socket *sock, int mode)
2067 struct sock *sk = sock->sk;
2070 if (mode < SHUT_RD || mode > SHUT_RDWR)
2073 * SHUT_RD (0) -> RCV_SHUTDOWN (1)
2074 * SHUT_WR (1) -> SEND_SHUTDOWN (2)
2075 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2079 unix_state_lock(sk);
2080 sk->sk_shutdown |= mode;
2081 other = unix_peer(sk);
2084 unix_state_unlock(sk);
2085 sk->sk_state_change(sk);
2088 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2092 if (mode&RCV_SHUTDOWN)
2093 peer_mode |= SEND_SHUTDOWN;
2094 if (mode&SEND_SHUTDOWN)
2095 peer_mode |= RCV_SHUTDOWN;
2096 unix_state_lock(other);
2097 other->sk_shutdown |= peer_mode;
2098 unix_state_unlock(other);
2099 other->sk_state_change(other);
2100 if (peer_mode == SHUTDOWN_MASK)
2101 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2102 else if (peer_mode & RCV_SHUTDOWN)
2103 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2111 long unix_inq_len(struct sock *sk)
2113 struct sk_buff *skb;
2116 if (sk->sk_state == TCP_LISTEN)
2119 spin_lock(&sk->sk_receive_queue.lock);
2120 if (sk->sk_type == SOCK_STREAM ||
2121 sk->sk_type == SOCK_SEQPACKET) {
2122 skb_queue_walk(&sk->sk_receive_queue, skb)
2125 skb = skb_peek(&sk->sk_receive_queue);
2129 spin_unlock(&sk->sk_receive_queue.lock);
2133 EXPORT_SYMBOL_GPL(unix_inq_len);
2135 long unix_outq_len(struct sock *sk)
2137 return sk_wmem_alloc_get(sk);
2139 EXPORT_SYMBOL_GPL(unix_outq_len);
2141 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2143 struct sock *sk = sock->sk;
2149 amount = unix_outq_len(sk);
2150 err = put_user(amount, (int __user *)arg);
2153 amount = unix_inq_len(sk);
2157 err = put_user(amount, (int __user *)arg);
2166 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2168 struct sock *sk = sock->sk;
2171 sock_poll_wait(file, sk_sleep(sk), wait);
2174 /* exceptional events? */
2177 if (sk->sk_shutdown == SHUTDOWN_MASK)
2179 if (sk->sk_shutdown & RCV_SHUTDOWN)
2180 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2183 if (!skb_queue_empty(&sk->sk_receive_queue))
2184 mask |= POLLIN | POLLRDNORM;
2186 /* Connection-based need to check for termination and startup */
2187 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2188 sk->sk_state == TCP_CLOSE)
2192 * we set writable also when the other side has shut down the
2193 * connection. This prevents stuck sockets.
2195 if (unix_writable(sk))
2196 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2201 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2204 struct sock *sk = sock->sk, *other;
2205 unsigned int mask, writable;
2207 sock_poll_wait(file, sk_sleep(sk), wait);
2210 /* exceptional events? */
2211 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2213 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2215 if (sk->sk_shutdown & RCV_SHUTDOWN)
2216 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2217 if (sk->sk_shutdown == SHUTDOWN_MASK)
2221 if (!skb_queue_empty(&sk->sk_receive_queue))
2222 mask |= POLLIN | POLLRDNORM;
2224 /* Connection-based need to check for termination and startup */
2225 if (sk->sk_type == SOCK_SEQPACKET) {
2226 if (sk->sk_state == TCP_CLOSE)
2228 /* connection hasn't started yet? */
2229 if (sk->sk_state == TCP_SYN_SENT)
2233 /* No write status requested, avoid expensive OUT tests. */
2234 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2237 writable = unix_writable(sk);
2238 other = unix_peer_get(sk);
2240 if (unix_peer(other) != sk) {
2241 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2242 if (unix_recvq_full(other))
2249 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2251 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2256 #ifdef CONFIG_PROC_FS
2258 #define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2260 #define get_bucket(x) ((x) >> BUCKET_SPACE)
2261 #define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2262 #define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2264 static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2266 unsigned long offset = get_offset(*pos);
2267 unsigned long bucket = get_bucket(*pos);
2269 unsigned long count = 0;
2271 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2272 if (sock_net(sk) != seq_file_net(seq))
2274 if (++count == offset)
2281 static struct sock *unix_next_socket(struct seq_file *seq,
2285 unsigned long bucket;
2287 while (sk > (struct sock *)SEQ_START_TOKEN) {
2291 if (sock_net(sk) == seq_file_net(seq))
2296 sk = unix_from_bucket(seq, pos);
2301 bucket = get_bucket(*pos) + 1;
2302 *pos = set_bucket_offset(bucket, 1);
2303 } while (bucket < ARRAY_SIZE(unix_socket_table));
2308 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2309 __acquires(unix_table_lock)
2311 spin_lock(&unix_table_lock);
2314 return SEQ_START_TOKEN;
2316 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2319 return unix_next_socket(seq, NULL, pos);
2322 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2325 return unix_next_socket(seq, v, pos);
2328 static void unix_seq_stop(struct seq_file *seq, void *v)
2329 __releases(unix_table_lock)
2331 spin_unlock(&unix_table_lock);
2334 static int unix_seq_show(struct seq_file *seq, void *v)
2337 if (v == SEQ_START_TOKEN)
2338 seq_puts(seq, "Num RefCount Protocol Flags Type St "
2342 struct unix_sock *u = unix_sk(s);
2345 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2347 atomic_read(&s->sk_refcnt),
2349 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2352 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2353 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2361 len = u->addr->len - sizeof(short);
2362 if (!UNIX_ABSTRACT(s))
2368 for ( ; i < len; i++)
2369 seq_putc(seq, u->addr->name->sun_path[i]);
2371 unix_state_unlock(s);
2372 seq_putc(seq, '\n');
2378 static const struct seq_operations unix_seq_ops = {
2379 .start = unix_seq_start,
2380 .next = unix_seq_next,
2381 .stop = unix_seq_stop,
2382 .show = unix_seq_show,
2385 static int unix_seq_open(struct inode *inode, struct file *file)
2387 return seq_open_net(inode, file, &unix_seq_ops,
2388 sizeof(struct seq_net_private));
2391 static const struct file_operations unix_seq_fops = {
2392 .owner = THIS_MODULE,
2393 .open = unix_seq_open,
2395 .llseek = seq_lseek,
2396 .release = seq_release_net,
2401 static const struct net_proto_family unix_family_ops = {
2403 .create = unix_create,
2404 .owner = THIS_MODULE,
2408 static int __net_init unix_net_init(struct net *net)
2410 int error = -ENOMEM;
2412 net->unx.sysctl_max_dgram_qlen = 10;
2413 if (unix_sysctl_register(net))
2416 #ifdef CONFIG_PROC_FS
2417 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2418 unix_sysctl_unregister(net);
2427 static void __net_exit unix_net_exit(struct net *net)
2429 unix_sysctl_unregister(net);
2430 remove_proc_entry("unix", net->proc_net);
2433 static struct pernet_operations unix_net_ops = {
2434 .init = unix_net_init,
2435 .exit = unix_net_exit,
2438 static int __init af_unix_init(void)
2442 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2444 rc = proto_register(&unix_proto, 1);
2446 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2451 sock_register(&unix_family_ops);
2452 register_pernet_subsys(&unix_net_ops);
2457 static void __exit af_unix_exit(void)
2459 sock_unregister(PF_UNIX);
2460 proto_unregister(&unix_proto);
2461 unregister_pernet_subsys(&unix_net_ops);
2464 /* Earlier than device_initcall() so that other drivers invoking
2465 request_module() don't end up in a loop when modprobe tries
2466 to use a UNIX socket. But later than subsys_initcall() because
2467 we depend on stuff initialised there */
2468 fs_initcall(af_unix_init);
2469 module_exit(af_unix_exit);
2471 MODULE_LICENSE("GPL");
2472 MODULE_ALIAS_NETPROTO(PF_UNIX);