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1 /*
2  * NET4:        Implementation of BSD Unix domain sockets.
3  *
4  * Authors:     Alan Cox, <alan@lxorguk.ukuu.org.uk>
5  *
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.
10  *
11  * Fixes:
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
21  *                                      Mike Shaver's work.
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
28  *                                      reference counting
29  *              Kirk Petersen   :       Made this a module
30  *          Christoph Rohland   :       Elegant non-blocking accept/connect algorithm.
31  *                                      Lots of bug fixes.
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
43  *                                      dgram receiver.
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+)
51  *
52  *
53  * Known differences from reference BSD that was tested:
54  *
55  *      [TO FIX]
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).
60  *      [NOT TO FIX]
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)
68  *
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.
73  *
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
80  *                with BSD names.
81  */
82
83 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
84
85 #include <linux/module.h>
86 #include <linux/kernel.h>
87 #include <linux/signal.h>
88 #include <linux/sched.h>
89 #include <linux/errno.h>
90 #include <linux/string.h>
91 #include <linux/stat.h>
92 #include <linux/dcache.h>
93 #include <linux/namei.h>
94 #include <linux/socket.h>
95 #include <linux/un.h>
96 #include <linux/fcntl.h>
97 #include <linux/termios.h>
98 #include <linux/sockios.h>
99 #include <linux/net.h>
100 #include <linux/in.h>
101 #include <linux/fs.h>
102 #include <linux/slab.h>
103 #include <asm/uaccess.h>
104 #include <linux/skbuff.h>
105 #include <linux/netdevice.h>
106 #include <net/net_namespace.h>
107 #include <net/sock.h>
108 #include <net/tcp_states.h>
109 #include <net/af_unix.h>
110 #include <linux/proc_fs.h>
111 #include <linux/seq_file.h>
112 #include <net/scm.h>
113 #include <linux/init.h>
114 #include <linux/poll.h>
115 #include <linux/rtnetlink.h>
116 #include <linux/mount.h>
117 #include <net/checksum.h>
118 #include <linux/security.h>
119 #include <linux/freezer.h>
120
121 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
122 EXPORT_SYMBOL_GPL(unix_socket_table);
123 DEFINE_SPINLOCK(unix_table_lock);
124 EXPORT_SYMBOL_GPL(unix_table_lock);
125 static atomic_long_t unix_nr_socks;
126
127
128 static struct hlist_head *unix_sockets_unbound(void *addr)
129 {
130         unsigned long hash = (unsigned long)addr;
131
132         hash ^= hash >> 16;
133         hash ^= hash >> 8;
134         hash %= UNIX_HASH_SIZE;
135         return &unix_socket_table[UNIX_HASH_SIZE + hash];
136 }
137
138 #define UNIX_ABSTRACT(sk)       (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
139
140 #ifdef CONFIG_SECURITY_NETWORK
141 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
142 {
143         UNIXCB(skb).secid = scm->secid;
144 }
145
146 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
147 {
148         scm->secid = UNIXCB(skb).secid;
149 }
150
151 static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
152 {
153         return (scm->secid == UNIXCB(skb).secid);
154 }
155 #else
156 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
157 { }
158
159 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
160 { }
161
162 static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
163 {
164         return true;
165 }
166 #endif /* CONFIG_SECURITY_NETWORK */
167
168 /*
169  *  SMP locking strategy:
170  *    hash table is protected with spinlock unix_table_lock
171  *    each socket state is protected by separate spin lock.
172  */
173
174 static inline unsigned int unix_hash_fold(__wsum n)
175 {
176         unsigned int hash = (__force unsigned int)csum_fold(n);
177
178         hash ^= hash>>8;
179         return hash&(UNIX_HASH_SIZE-1);
180 }
181
182 #define unix_peer(sk) (unix_sk(sk)->peer)
183
184 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
185 {
186         return unix_peer(osk) == sk;
187 }
188
189 static inline int unix_may_send(struct sock *sk, struct sock *osk)
190 {
191         return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
192 }
193
194 static inline int unix_recvq_full(struct sock const *sk)
195 {
196         return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
197 }
198
199 struct sock *unix_peer_get(struct sock *s)
200 {
201         struct sock *peer;
202
203         unix_state_lock(s);
204         peer = unix_peer(s);
205         if (peer)
206                 sock_hold(peer);
207         unix_state_unlock(s);
208         return peer;
209 }
210 EXPORT_SYMBOL_GPL(unix_peer_get);
211
212 static inline void unix_release_addr(struct unix_address *addr)
213 {
214         if (atomic_dec_and_test(&addr->refcnt))
215                 kfree(addr);
216 }
217
218 /*
219  *      Check unix socket name:
220  *              - should be not zero length.
221  *              - if started by not zero, should be NULL terminated (FS object)
222  *              - if started by zero, it is abstract name.
223  */
224
225 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
226 {
227         if (len <= sizeof(short) || len > sizeof(*sunaddr))
228                 return -EINVAL;
229         if (!sunaddr || sunaddr->sun_family != AF_UNIX)
230                 return -EINVAL;
231         if (sunaddr->sun_path[0]) {
232                 /*
233                  * This may look like an off by one error but it is a bit more
234                  * subtle. 108 is the longest valid AF_UNIX path for a binding.
235                  * sun_path[108] doesn't as such exist.  However in kernel space
236                  * we are guaranteed that it is a valid memory location in our
237                  * kernel address buffer.
238                  */
239                 ((char *)sunaddr)[len] = 0;
240                 len = strlen(sunaddr->sun_path)+1+sizeof(short);
241                 return len;
242         }
243
244         *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
245         return len;
246 }
247
248 static void __unix_remove_socket(struct sock *sk)
249 {
250         sk_del_node_init(sk);
251 }
252
253 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
254 {
255         WARN_ON(!sk_unhashed(sk));
256         sk_add_node(sk, list);
257 }
258
259 static inline void unix_remove_socket(struct sock *sk)
260 {
261         spin_lock(&unix_table_lock);
262         __unix_remove_socket(sk);
263         spin_unlock(&unix_table_lock);
264 }
265
266 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
267 {
268         spin_lock(&unix_table_lock);
269         __unix_insert_socket(list, sk);
270         spin_unlock(&unix_table_lock);
271 }
272
273 static struct sock *__unix_find_socket_byname(struct net *net,
274                                               struct sockaddr_un *sunname,
275                                               int len, int type, unsigned int hash)
276 {
277         struct sock *s;
278
279         sk_for_each(s, &unix_socket_table[hash ^ type]) {
280                 struct unix_sock *u = unix_sk(s);
281
282                 if (!net_eq(sock_net(s), net))
283                         continue;
284
285                 if (u->addr->len == len &&
286                     !memcmp(u->addr->name, sunname, len))
287                         goto found;
288         }
289         s = NULL;
290 found:
291         return s;
292 }
293
294 static inline struct sock *unix_find_socket_byname(struct net *net,
295                                                    struct sockaddr_un *sunname,
296                                                    int len, int type,
297                                                    unsigned int hash)
298 {
299         struct sock *s;
300
301         spin_lock(&unix_table_lock);
302         s = __unix_find_socket_byname(net, sunname, len, type, hash);
303         if (s)
304                 sock_hold(s);
305         spin_unlock(&unix_table_lock);
306         return s;
307 }
308
309 static struct sock *unix_find_socket_byinode(struct inode *i)
310 {
311         struct sock *s;
312
313         spin_lock(&unix_table_lock);
314         sk_for_each(s,
315                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
316                 struct dentry *dentry = unix_sk(s)->path.dentry;
317
318                 if (dentry && d_backing_inode(dentry) == i) {
319                         sock_hold(s);
320                         goto found;
321                 }
322         }
323         s = NULL;
324 found:
325         spin_unlock(&unix_table_lock);
326         return s;
327 }
328
329 /* Support code for asymmetrically connected dgram sockets
330  *
331  * If a datagram socket is connected to a socket not itself connected
332  * to the first socket (eg, /dev/log), clients may only enqueue more
333  * messages if the present receive queue of the server socket is not
334  * "too large". This means there's a second writeability condition
335  * poll and sendmsg need to test. The dgram recv code will do a wake
336  * up on the peer_wait wait queue of a socket upon reception of a
337  * datagram which needs to be propagated to sleeping would-be writers
338  * since these might not have sent anything so far. This can't be
339  * accomplished via poll_wait because the lifetime of the server
340  * socket might be less than that of its clients if these break their
341  * association with it or if the server socket is closed while clients
342  * are still connected to it and there's no way to inform "a polling
343  * implementation" that it should let go of a certain wait queue
344  *
345  * In order to propagate a wake up, a wait_queue_t of the client
346  * socket is enqueued on the peer_wait queue of the server socket
347  * whose wake function does a wake_up on the ordinary client socket
348  * wait queue. This connection is established whenever a write (or
349  * poll for write) hit the flow control condition and broken when the
350  * association to the server socket is dissolved or after a wake up
351  * was relayed.
352  */
353
354 static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
355                                       void *key)
356 {
357         struct unix_sock *u;
358         wait_queue_head_t *u_sleep;
359
360         u = container_of(q, struct unix_sock, peer_wake);
361
362         __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
363                             q);
364         u->peer_wake.private = NULL;
365
366         /* relaying can only happen while the wq still exists */
367         u_sleep = sk_sleep(&u->sk);
368         if (u_sleep)
369                 wake_up_interruptible_poll(u_sleep, key);
370
371         return 0;
372 }
373
374 static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
375 {
376         struct unix_sock *u, *u_other;
377         int rc;
378
379         u = unix_sk(sk);
380         u_other = unix_sk(other);
381         rc = 0;
382         spin_lock(&u_other->peer_wait.lock);
383
384         if (!u->peer_wake.private) {
385                 u->peer_wake.private = other;
386                 __add_wait_queue(&u_other->peer_wait, &u->peer_wake);
387
388                 rc = 1;
389         }
390
391         spin_unlock(&u_other->peer_wait.lock);
392         return rc;
393 }
394
395 static void unix_dgram_peer_wake_disconnect(struct sock *sk,
396                                             struct sock *other)
397 {
398         struct unix_sock *u, *u_other;
399
400         u = unix_sk(sk);
401         u_other = unix_sk(other);
402         spin_lock(&u_other->peer_wait.lock);
403
404         if (u->peer_wake.private == other) {
405                 __remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
406                 u->peer_wake.private = NULL;
407         }
408
409         spin_unlock(&u_other->peer_wait.lock);
410 }
411
412 static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
413                                                    struct sock *other)
414 {
415         unix_dgram_peer_wake_disconnect(sk, other);
416         wake_up_interruptible_poll(sk_sleep(sk),
417                                    POLLOUT |
418                                    POLLWRNORM |
419                                    POLLWRBAND);
420 }
421
422 /* preconditions:
423  *      - unix_peer(sk) == other
424  *      - association is stable
425  */
426 static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
427 {
428         int connected;
429
430         connected = unix_dgram_peer_wake_connect(sk, other);
431
432         if (unix_recvq_full(other))
433                 return 1;
434
435         if (connected)
436                 unix_dgram_peer_wake_disconnect(sk, other);
437
438         return 0;
439 }
440
441 static int unix_writable(const struct sock *sk)
442 {
443         return sk->sk_state != TCP_LISTEN &&
444                (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
445 }
446
447 static void unix_write_space(struct sock *sk)
448 {
449         struct socket_wq *wq;
450
451         rcu_read_lock();
452         if (unix_writable(sk)) {
453                 wq = rcu_dereference(sk->sk_wq);
454                 if (skwq_has_sleeper(wq))
455                         wake_up_interruptible_sync_poll(&wq->wait,
456                                 POLLOUT | POLLWRNORM | POLLWRBAND);
457                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
458         }
459         rcu_read_unlock();
460 }
461
462 /* When dgram socket disconnects (or changes its peer), we clear its receive
463  * queue of packets arrived from previous peer. First, it allows to do
464  * flow control based only on wmem_alloc; second, sk connected to peer
465  * may receive messages only from that peer. */
466 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
467 {
468         if (!skb_queue_empty(&sk->sk_receive_queue)) {
469                 skb_queue_purge(&sk->sk_receive_queue);
470                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
471
472                 /* If one link of bidirectional dgram pipe is disconnected,
473                  * we signal error. Messages are lost. Do not make this,
474                  * when peer was not connected to us.
475                  */
476                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
477                         other->sk_err = ECONNRESET;
478                         other->sk_error_report(other);
479                 }
480         }
481 }
482
483 static void unix_sock_destructor(struct sock *sk)
484 {
485         struct unix_sock *u = unix_sk(sk);
486
487         skb_queue_purge(&sk->sk_receive_queue);
488
489         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
490         WARN_ON(!sk_unhashed(sk));
491         WARN_ON(sk->sk_socket);
492         if (!sock_flag(sk, SOCK_DEAD)) {
493                 pr_info("Attempt to release alive unix socket: %p\n", sk);
494                 return;
495         }
496
497         if (u->addr)
498                 unix_release_addr(u->addr);
499
500         atomic_long_dec(&unix_nr_socks);
501         local_bh_disable();
502         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
503         local_bh_enable();
504 #ifdef UNIX_REFCNT_DEBUG
505         pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
506                 atomic_long_read(&unix_nr_socks));
507 #endif
508 }
509
510 static void unix_release_sock(struct sock *sk, int embrion)
511 {
512         struct unix_sock *u = unix_sk(sk);
513         struct path path;
514         struct sock *skpair;
515         struct sk_buff *skb;
516         int state;
517
518         unix_remove_socket(sk);
519
520         /* Clear state */
521         unix_state_lock(sk);
522         sock_orphan(sk);
523         sk->sk_shutdown = SHUTDOWN_MASK;
524         path         = u->path;
525         u->path.dentry = NULL;
526         u->path.mnt = NULL;
527         state = sk->sk_state;
528         sk->sk_state = TCP_CLOSE;
529         unix_state_unlock(sk);
530
531         wake_up_interruptible_all(&u->peer_wait);
532
533         skpair = unix_peer(sk);
534
535         if (skpair != NULL) {
536                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
537                         unix_state_lock(skpair);
538                         /* No more writes */
539                         skpair->sk_shutdown = SHUTDOWN_MASK;
540                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
541                                 skpair->sk_err = ECONNRESET;
542                         unix_state_unlock(skpair);
543                         skpair->sk_state_change(skpair);
544                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
545                 }
546
547                 unix_dgram_peer_wake_disconnect(sk, skpair);
548                 sock_put(skpair); /* It may now die */
549                 unix_peer(sk) = NULL;
550         }
551
552         /* Try to flush out this socket. Throw out buffers at least */
553
554         while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
555                 if (state == TCP_LISTEN)
556                         unix_release_sock(skb->sk, 1);
557                 /* passed fds are erased in the kfree_skb hook        */
558                 UNIXCB(skb).consumed = skb->len;
559                 kfree_skb(skb);
560         }
561
562         if (path.dentry)
563                 path_put(&path);
564
565         sock_put(sk);
566
567         /* ---- Socket is dead now and most probably destroyed ---- */
568
569         /*
570          * Fixme: BSD difference: In BSD all sockets connected to us get
571          *        ECONNRESET and we die on the spot. In Linux we behave
572          *        like files and pipes do and wait for the last
573          *        dereference.
574          *
575          * Can't we simply set sock->err?
576          *
577          *        What the above comment does talk about? --ANK(980817)
578          */
579
580         if (unix_tot_inflight)
581                 unix_gc();              /* Garbage collect fds */
582 }
583
584 static void init_peercred(struct sock *sk)
585 {
586         put_pid(sk->sk_peer_pid);
587         if (sk->sk_peer_cred)
588                 put_cred(sk->sk_peer_cred);
589         sk->sk_peer_pid  = get_pid(task_tgid(current));
590         sk->sk_peer_cred = get_current_cred();
591 }
592
593 static void copy_peercred(struct sock *sk, struct sock *peersk)
594 {
595         put_pid(sk->sk_peer_pid);
596         if (sk->sk_peer_cred)
597                 put_cred(sk->sk_peer_cred);
598         sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
599         sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
600 }
601
602 static int unix_listen(struct socket *sock, int backlog)
603 {
604         int err;
605         struct sock *sk = sock->sk;
606         struct unix_sock *u = unix_sk(sk);
607         struct pid *old_pid = NULL;
608
609         err = -EOPNOTSUPP;
610         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
611                 goto out;       /* Only stream/seqpacket sockets accept */
612         err = -EINVAL;
613         if (!u->addr)
614                 goto out;       /* No listens on an unbound socket */
615         unix_state_lock(sk);
616         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
617                 goto out_unlock;
618         if (backlog > sk->sk_max_ack_backlog)
619                 wake_up_interruptible_all(&u->peer_wait);
620         sk->sk_max_ack_backlog  = backlog;
621         sk->sk_state            = TCP_LISTEN;
622         /* set credentials so connect can copy them */
623         init_peercred(sk);
624         err = 0;
625
626 out_unlock:
627         unix_state_unlock(sk);
628         put_pid(old_pid);
629 out:
630         return err;
631 }
632
633 static int unix_release(struct socket *);
634 static int unix_bind(struct socket *, struct sockaddr *, int);
635 static int unix_stream_connect(struct socket *, struct sockaddr *,
636                                int addr_len, int flags);
637 static int unix_socketpair(struct socket *, struct socket *);
638 static int unix_accept(struct socket *, struct socket *, int);
639 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
640 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
641 static unsigned int unix_dgram_poll(struct file *, struct socket *,
642                                     poll_table *);
643 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
644 static int unix_shutdown(struct socket *, int);
645 static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
646 static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
647 static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
648                                     size_t size, int flags);
649 static ssize_t unix_stream_splice_read(struct socket *,  loff_t *ppos,
650                                        struct pipe_inode_info *, size_t size,
651                                        unsigned int flags);
652 static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
653 static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
654 static int unix_dgram_connect(struct socket *, struct sockaddr *,
655                               int, int);
656 static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
657 static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
658                                   int);
659
660 static int unix_set_peek_off(struct sock *sk, int val)
661 {
662         struct unix_sock *u = unix_sk(sk);
663
664         if (mutex_lock_interruptible(&u->readlock))
665                 return -EINTR;
666
667         sk->sk_peek_off = val;
668         mutex_unlock(&u->readlock);
669
670         return 0;
671 }
672
673
674 static const struct proto_ops unix_stream_ops = {
675         .family =       PF_UNIX,
676         .owner =        THIS_MODULE,
677         .release =      unix_release,
678         .bind =         unix_bind,
679         .connect =      unix_stream_connect,
680         .socketpair =   unix_socketpair,
681         .accept =       unix_accept,
682         .getname =      unix_getname,
683         .poll =         unix_poll,
684         .ioctl =        unix_ioctl,
685         .listen =       unix_listen,
686         .shutdown =     unix_shutdown,
687         .setsockopt =   sock_no_setsockopt,
688         .getsockopt =   sock_no_getsockopt,
689         .sendmsg =      unix_stream_sendmsg,
690         .recvmsg =      unix_stream_recvmsg,
691         .mmap =         sock_no_mmap,
692         .sendpage =     unix_stream_sendpage,
693         .splice_read =  unix_stream_splice_read,
694         .set_peek_off = unix_set_peek_off,
695 };
696
697 static const struct proto_ops unix_dgram_ops = {
698         .family =       PF_UNIX,
699         .owner =        THIS_MODULE,
700         .release =      unix_release,
701         .bind =         unix_bind,
702         .connect =      unix_dgram_connect,
703         .socketpair =   unix_socketpair,
704         .accept =       sock_no_accept,
705         .getname =      unix_getname,
706         .poll =         unix_dgram_poll,
707         .ioctl =        unix_ioctl,
708         .listen =       sock_no_listen,
709         .shutdown =     unix_shutdown,
710         .setsockopt =   sock_no_setsockopt,
711         .getsockopt =   sock_no_getsockopt,
712         .sendmsg =      unix_dgram_sendmsg,
713         .recvmsg =      unix_dgram_recvmsg,
714         .mmap =         sock_no_mmap,
715         .sendpage =     sock_no_sendpage,
716         .set_peek_off = unix_set_peek_off,
717 };
718
719 static const struct proto_ops unix_seqpacket_ops = {
720         .family =       PF_UNIX,
721         .owner =        THIS_MODULE,
722         .release =      unix_release,
723         .bind =         unix_bind,
724         .connect =      unix_stream_connect,
725         .socketpair =   unix_socketpair,
726         .accept =       unix_accept,
727         .getname =      unix_getname,
728         .poll =         unix_dgram_poll,
729         .ioctl =        unix_ioctl,
730         .listen =       unix_listen,
731         .shutdown =     unix_shutdown,
732         .setsockopt =   sock_no_setsockopt,
733         .getsockopt =   sock_no_getsockopt,
734         .sendmsg =      unix_seqpacket_sendmsg,
735         .recvmsg =      unix_seqpacket_recvmsg,
736         .mmap =         sock_no_mmap,
737         .sendpage =     sock_no_sendpage,
738         .set_peek_off = unix_set_peek_off,
739 };
740
741 static struct proto unix_proto = {
742         .name                   = "UNIX",
743         .owner                  = THIS_MODULE,
744         .obj_size               = sizeof(struct unix_sock),
745 };
746
747 /*
748  * AF_UNIX sockets do not interact with hardware, hence they
749  * dont trigger interrupts - so it's safe for them to have
750  * bh-unsafe locking for their sk_receive_queue.lock. Split off
751  * this special lock-class by reinitializing the spinlock key:
752  */
753 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
754
755 static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
756 {
757         struct sock *sk = NULL;
758         struct unix_sock *u;
759
760         atomic_long_inc(&unix_nr_socks);
761         if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
762                 goto out;
763
764         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
765         if (!sk)
766                 goto out;
767
768         sock_init_data(sock, sk);
769         lockdep_set_class(&sk->sk_receive_queue.lock,
770                                 &af_unix_sk_receive_queue_lock_key);
771
772         sk->sk_write_space      = unix_write_space;
773         sk->sk_max_ack_backlog  = net->unx.sysctl_max_dgram_qlen;
774         sk->sk_destruct         = unix_sock_destructor;
775         u         = unix_sk(sk);
776         u->path.dentry = NULL;
777         u->path.mnt = NULL;
778         spin_lock_init(&u->lock);
779         atomic_long_set(&u->inflight, 0);
780         INIT_LIST_HEAD(&u->link);
781         mutex_init(&u->readlock); /* single task reading lock */
782         init_waitqueue_head(&u->peer_wait);
783         init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
784         unix_insert_socket(unix_sockets_unbound(sk), sk);
785 out:
786         if (sk == NULL)
787                 atomic_long_dec(&unix_nr_socks);
788         else {
789                 local_bh_disable();
790                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
791                 local_bh_enable();
792         }
793         return sk;
794 }
795
796 static int unix_create(struct net *net, struct socket *sock, int protocol,
797                        int kern)
798 {
799         if (protocol && protocol != PF_UNIX)
800                 return -EPROTONOSUPPORT;
801
802         sock->state = SS_UNCONNECTED;
803
804         switch (sock->type) {
805         case SOCK_STREAM:
806                 sock->ops = &unix_stream_ops;
807                 break;
808                 /*
809                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
810                  *      nothing uses it.
811                  */
812         case SOCK_RAW:
813                 sock->type = SOCK_DGRAM;
814         case SOCK_DGRAM:
815                 sock->ops = &unix_dgram_ops;
816                 break;
817         case SOCK_SEQPACKET:
818                 sock->ops = &unix_seqpacket_ops;
819                 break;
820         default:
821                 return -ESOCKTNOSUPPORT;
822         }
823
824         return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
825 }
826
827 static int unix_release(struct socket *sock)
828 {
829         struct sock *sk = sock->sk;
830
831         if (!sk)
832                 return 0;
833
834         unix_release_sock(sk, 0);
835         sock->sk = NULL;
836
837         return 0;
838 }
839
840 static int unix_autobind(struct socket *sock)
841 {
842         struct sock *sk = sock->sk;
843         struct net *net = sock_net(sk);
844         struct unix_sock *u = unix_sk(sk);
845         static u32 ordernum = 1;
846         struct unix_address *addr;
847         int err;
848         unsigned int retries = 0;
849
850         err = mutex_lock_interruptible(&u->readlock);
851         if (err)
852                 return err;
853
854         err = 0;
855         if (u->addr)
856                 goto out;
857
858         err = -ENOMEM;
859         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
860         if (!addr)
861                 goto out;
862
863         addr->name->sun_family = AF_UNIX;
864         atomic_set(&addr->refcnt, 1);
865
866 retry:
867         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
868         addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
869
870         spin_lock(&unix_table_lock);
871         ordernum = (ordernum+1)&0xFFFFF;
872
873         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
874                                       addr->hash)) {
875                 spin_unlock(&unix_table_lock);
876                 /*
877                  * __unix_find_socket_byname() may take long time if many names
878                  * are already in use.
879                  */
880                 cond_resched();
881                 /* Give up if all names seems to be in use. */
882                 if (retries++ == 0xFFFFF) {
883                         err = -ENOSPC;
884                         kfree(addr);
885                         goto out;
886                 }
887                 goto retry;
888         }
889         addr->hash ^= sk->sk_type;
890
891         __unix_remove_socket(sk);
892         u->addr = addr;
893         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
894         spin_unlock(&unix_table_lock);
895         err = 0;
896
897 out:    mutex_unlock(&u->readlock);
898         return err;
899 }
900
901 static struct sock *unix_find_other(struct net *net,
902                                     struct sockaddr_un *sunname, int len,
903                                     int type, unsigned int hash, int *error)
904 {
905         struct sock *u;
906         struct path path;
907         int err = 0;
908
909         if (sunname->sun_path[0]) {
910                 struct inode *inode;
911                 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
912                 if (err)
913                         goto fail;
914                 inode = d_backing_inode(path.dentry);
915                 err = inode_permission(inode, MAY_WRITE);
916                 if (err)
917                         goto put_fail;
918
919                 err = -ECONNREFUSED;
920                 if (!S_ISSOCK(inode->i_mode))
921                         goto put_fail;
922                 u = unix_find_socket_byinode(inode);
923                 if (!u)
924                         goto put_fail;
925
926                 if (u->sk_type == type)
927                         touch_atime(&path);
928
929                 path_put(&path);
930
931                 err = -EPROTOTYPE;
932                 if (u->sk_type != type) {
933                         sock_put(u);
934                         goto fail;
935                 }
936         } else {
937                 err = -ECONNREFUSED;
938                 u = unix_find_socket_byname(net, sunname, len, type, hash);
939                 if (u) {
940                         struct dentry *dentry;
941                         dentry = unix_sk(u)->path.dentry;
942                         if (dentry)
943                                 touch_atime(&unix_sk(u)->path);
944                 } else
945                         goto fail;
946         }
947         return u;
948
949 put_fail:
950         path_put(&path);
951 fail:
952         *error = err;
953         return NULL;
954 }
955
956 static int unix_mknod(struct dentry *dentry, struct path *path, umode_t mode,
957                       struct path *res)
958 {
959         int err;
960
961         err = security_path_mknod(path, dentry, mode, 0);
962         if (!err) {
963                 err = vfs_mknod(d_inode(path->dentry), dentry, mode, 0);
964                 if (!err) {
965                         res->mnt = mntget(path->mnt);
966                         res->dentry = dget(dentry);
967                 }
968         }
969
970         return err;
971 }
972
973 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
974 {
975         struct sock *sk = sock->sk;
976         struct net *net = sock_net(sk);
977         struct unix_sock *u = unix_sk(sk);
978         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
979         char *sun_path = sunaddr->sun_path;
980         int err, name_err;
981         unsigned int hash;
982         struct unix_address *addr;
983         struct hlist_head *list;
984         struct path path;
985         struct dentry *dentry;
986
987         err = -EINVAL;
988         if (sunaddr->sun_family != AF_UNIX)
989                 goto out;
990
991         if (addr_len == sizeof(short)) {
992                 err = unix_autobind(sock);
993                 goto out;
994         }
995
996         err = unix_mkname(sunaddr, addr_len, &hash);
997         if (err < 0)
998                 goto out;
999         addr_len = err;
1000
1001         name_err = 0;
1002         dentry = NULL;
1003         if (sun_path[0]) {
1004                 /* Get the parent directory, calculate the hash for last
1005                  * component.
1006                  */
1007                 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
1008
1009                 if (IS_ERR(dentry)) {
1010                         /* delay report until after 'already bound' check */
1011                         name_err = PTR_ERR(dentry);
1012                         dentry = NULL;
1013                 }
1014         }
1015
1016         err = mutex_lock_interruptible(&u->readlock);
1017         if (err)
1018                 goto out_path;
1019
1020         err = -EINVAL;
1021         if (u->addr)
1022                 goto out_up;
1023
1024         if (name_err) {
1025                 err = name_err == -EEXIST ? -EADDRINUSE : name_err;
1026                 goto out_up;
1027         }
1028
1029         err = -ENOMEM;
1030         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
1031         if (!addr)
1032                 goto out_up;
1033
1034         memcpy(addr->name, sunaddr, addr_len);
1035         addr->len = addr_len;
1036         addr->hash = hash ^ sk->sk_type;
1037         atomic_set(&addr->refcnt, 1);
1038
1039         if (dentry) {
1040                 struct path u_path;
1041                 umode_t mode = S_IFSOCK |
1042                        (SOCK_INODE(sock)->i_mode & ~current_umask());
1043                 err = unix_mknod(dentry, &path, mode, &u_path);
1044                 if (err) {
1045                         if (err == -EEXIST)
1046                                 err = -EADDRINUSE;
1047                         unix_release_addr(addr);
1048                         goto out_up;
1049                 }
1050                 addr->hash = UNIX_HASH_SIZE;
1051                 hash = d_backing_inode(dentry)->i_ino & (UNIX_HASH_SIZE - 1);
1052                 spin_lock(&unix_table_lock);
1053                 u->path = u_path;
1054                 list = &unix_socket_table[hash];
1055         } else {
1056                 spin_lock(&unix_table_lock);
1057                 err = -EADDRINUSE;
1058                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
1059                                               sk->sk_type, hash)) {
1060                         unix_release_addr(addr);
1061                         goto out_unlock;
1062                 }
1063
1064                 list = &unix_socket_table[addr->hash];
1065         }
1066
1067         err = 0;
1068         __unix_remove_socket(sk);
1069         u->addr = addr;
1070         __unix_insert_socket(list, sk);
1071
1072 out_unlock:
1073         spin_unlock(&unix_table_lock);
1074 out_up:
1075         mutex_unlock(&u->readlock);
1076 out_path:
1077         if (dentry)
1078                 done_path_create(&path, dentry);
1079
1080 out:
1081         return err;
1082 }
1083
1084 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
1085 {
1086         if (unlikely(sk1 == sk2) || !sk2) {
1087                 unix_state_lock(sk1);
1088                 return;
1089         }
1090         if (sk1 < sk2) {
1091                 unix_state_lock(sk1);
1092                 unix_state_lock_nested(sk2);
1093         } else {
1094                 unix_state_lock(sk2);
1095                 unix_state_lock_nested(sk1);
1096         }
1097 }
1098
1099 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
1100 {
1101         if (unlikely(sk1 == sk2) || !sk2) {
1102                 unix_state_unlock(sk1);
1103                 return;
1104         }
1105         unix_state_unlock(sk1);
1106         unix_state_unlock(sk2);
1107 }
1108
1109 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
1110                               int alen, int flags)
1111 {
1112         struct sock *sk = sock->sk;
1113         struct net *net = sock_net(sk);
1114         struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
1115         struct sock *other;
1116         unsigned int hash;
1117         int err;
1118
1119         if (addr->sa_family != AF_UNSPEC) {
1120                 err = unix_mkname(sunaddr, alen, &hash);
1121                 if (err < 0)
1122                         goto out;
1123                 alen = err;
1124
1125                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
1126                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
1127                         goto out;
1128
1129 restart:
1130                 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
1131                 if (!other)
1132                         goto out;
1133
1134                 unix_state_double_lock(sk, other);
1135
1136                 /* Apparently VFS overslept socket death. Retry. */
1137                 if (sock_flag(other, SOCK_DEAD)) {
1138                         unix_state_double_unlock(sk, other);
1139                         sock_put(other);
1140                         goto restart;
1141                 }
1142
1143                 err = -EPERM;
1144                 if (!unix_may_send(sk, other))
1145                         goto out_unlock;
1146
1147                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1148                 if (err)
1149                         goto out_unlock;
1150
1151         } else {
1152                 /*
1153                  *      1003.1g breaking connected state with AF_UNSPEC
1154                  */
1155                 other = NULL;
1156                 unix_state_double_lock(sk, other);
1157         }
1158
1159         /*
1160          * If it was connected, reconnect.
1161          */
1162         if (unix_peer(sk)) {
1163                 struct sock *old_peer = unix_peer(sk);
1164                 unix_peer(sk) = other;
1165                 unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
1166
1167                 unix_state_double_unlock(sk, other);
1168
1169                 if (other != old_peer)
1170                         unix_dgram_disconnected(sk, old_peer);
1171                 sock_put(old_peer);
1172         } else {
1173                 unix_peer(sk) = other;
1174                 unix_state_double_unlock(sk, other);
1175         }
1176         return 0;
1177
1178 out_unlock:
1179         unix_state_double_unlock(sk, other);
1180         sock_put(other);
1181 out:
1182         return err;
1183 }
1184
1185 static long unix_wait_for_peer(struct sock *other, long timeo)
1186 {
1187         struct unix_sock *u = unix_sk(other);
1188         int sched;
1189         DEFINE_WAIT(wait);
1190
1191         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1192
1193         sched = !sock_flag(other, SOCK_DEAD) &&
1194                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1195                 unix_recvq_full(other);
1196
1197         unix_state_unlock(other);
1198
1199         if (sched)
1200                 timeo = schedule_timeout(timeo);
1201
1202         finish_wait(&u->peer_wait, &wait);
1203         return timeo;
1204 }
1205
1206 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1207                                int addr_len, int flags)
1208 {
1209         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1210         struct sock *sk = sock->sk;
1211         struct net *net = sock_net(sk);
1212         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1213         struct sock *newsk = NULL;
1214         struct sock *other = NULL;
1215         struct sk_buff *skb = NULL;
1216         unsigned int hash;
1217         int st;
1218         int err;
1219         long timeo;
1220
1221         err = unix_mkname(sunaddr, addr_len, &hash);
1222         if (err < 0)
1223                 goto out;
1224         addr_len = err;
1225
1226         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1227             (err = unix_autobind(sock)) != 0)
1228                 goto out;
1229
1230         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1231
1232         /* First of all allocate resources.
1233            If we will make it after state is locked,
1234            we will have to recheck all again in any case.
1235          */
1236
1237         err = -ENOMEM;
1238
1239         /* create new sock for complete connection */
1240         newsk = unix_create1(sock_net(sk), NULL, 0);
1241         if (newsk == NULL)
1242                 goto out;
1243
1244         /* Allocate skb for sending to listening sock */
1245         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1246         if (skb == NULL)
1247                 goto out;
1248
1249 restart:
1250         /*  Find listening sock. */
1251         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1252         if (!other)
1253                 goto out;
1254
1255         /* Latch state of peer */
1256         unix_state_lock(other);
1257
1258         /* Apparently VFS overslept socket death. Retry. */
1259         if (sock_flag(other, SOCK_DEAD)) {
1260                 unix_state_unlock(other);
1261                 sock_put(other);
1262                 goto restart;
1263         }
1264
1265         err = -ECONNREFUSED;
1266         if (other->sk_state != TCP_LISTEN)
1267                 goto out_unlock;
1268         if (other->sk_shutdown & RCV_SHUTDOWN)
1269                 goto out_unlock;
1270
1271         if (unix_recvq_full(other)) {
1272                 err = -EAGAIN;
1273                 if (!timeo)
1274                         goto out_unlock;
1275
1276                 timeo = unix_wait_for_peer(other, timeo);
1277
1278                 err = sock_intr_errno(timeo);
1279                 if (signal_pending(current))
1280                         goto out;
1281                 sock_put(other);
1282                 goto restart;
1283         }
1284
1285         /* Latch our state.
1286
1287            It is tricky place. We need to grab our state lock and cannot
1288            drop lock on peer. It is dangerous because deadlock is
1289            possible. Connect to self case and simultaneous
1290            attempt to connect are eliminated by checking socket
1291            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1292            check this before attempt to grab lock.
1293
1294            Well, and we have to recheck the state after socket locked.
1295          */
1296         st = sk->sk_state;
1297
1298         switch (st) {
1299         case TCP_CLOSE:
1300                 /* This is ok... continue with connect */
1301                 break;
1302         case TCP_ESTABLISHED:
1303                 /* Socket is already connected */
1304                 err = -EISCONN;
1305                 goto out_unlock;
1306         default:
1307                 err = -EINVAL;
1308                 goto out_unlock;
1309         }
1310
1311         unix_state_lock_nested(sk);
1312
1313         if (sk->sk_state != st) {
1314                 unix_state_unlock(sk);
1315                 unix_state_unlock(other);
1316                 sock_put(other);
1317                 goto restart;
1318         }
1319
1320         err = security_unix_stream_connect(sk, other, newsk);
1321         if (err) {
1322                 unix_state_unlock(sk);
1323                 goto out_unlock;
1324         }
1325
1326         /* The way is open! Fastly set all the necessary fields... */
1327
1328         sock_hold(sk);
1329         unix_peer(newsk)        = sk;
1330         newsk->sk_state         = TCP_ESTABLISHED;
1331         newsk->sk_type          = sk->sk_type;
1332         init_peercred(newsk);
1333         newu = unix_sk(newsk);
1334         RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
1335         otheru = unix_sk(other);
1336
1337         /* copy address information from listening to new sock*/
1338         if (otheru->addr) {
1339                 atomic_inc(&otheru->addr->refcnt);
1340                 newu->addr = otheru->addr;
1341         }
1342         if (otheru->path.dentry) {
1343                 path_get(&otheru->path);
1344                 newu->path = otheru->path;
1345         }
1346
1347         /* Set credentials */
1348         copy_peercred(sk, other);
1349
1350         sock->state     = SS_CONNECTED;
1351         sk->sk_state    = TCP_ESTABLISHED;
1352         sock_hold(newsk);
1353
1354         smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
1355         unix_peer(sk)   = newsk;
1356
1357         unix_state_unlock(sk);
1358
1359         /* take ten and and send info to listening sock */
1360         spin_lock(&other->sk_receive_queue.lock);
1361         __skb_queue_tail(&other->sk_receive_queue, skb);
1362         spin_unlock(&other->sk_receive_queue.lock);
1363         unix_state_unlock(other);
1364         other->sk_data_ready(other);
1365         sock_put(other);
1366         return 0;
1367
1368 out_unlock:
1369         if (other)
1370                 unix_state_unlock(other);
1371
1372 out:
1373         kfree_skb(skb);
1374         if (newsk)
1375                 unix_release_sock(newsk, 0);
1376         if (other)
1377                 sock_put(other);
1378         return err;
1379 }
1380
1381 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1382 {
1383         struct sock *ska = socka->sk, *skb = sockb->sk;
1384
1385         /* Join our sockets back to back */
1386         sock_hold(ska);
1387         sock_hold(skb);
1388         unix_peer(ska) = skb;
1389         unix_peer(skb) = ska;
1390         init_peercred(ska);
1391         init_peercred(skb);
1392
1393         if (ska->sk_type != SOCK_DGRAM) {
1394                 ska->sk_state = TCP_ESTABLISHED;
1395                 skb->sk_state = TCP_ESTABLISHED;
1396                 socka->state  = SS_CONNECTED;
1397                 sockb->state  = SS_CONNECTED;
1398         }
1399         return 0;
1400 }
1401
1402 static void unix_sock_inherit_flags(const struct socket *old,
1403                                     struct socket *new)
1404 {
1405         if (test_bit(SOCK_PASSCRED, &old->flags))
1406                 set_bit(SOCK_PASSCRED, &new->flags);
1407         if (test_bit(SOCK_PASSSEC, &old->flags))
1408                 set_bit(SOCK_PASSSEC, &new->flags);
1409 }
1410
1411 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1412 {
1413         struct sock *sk = sock->sk;
1414         struct sock *tsk;
1415         struct sk_buff *skb;
1416         int err;
1417
1418         err = -EOPNOTSUPP;
1419         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1420                 goto out;
1421
1422         err = -EINVAL;
1423         if (sk->sk_state != TCP_LISTEN)
1424                 goto out;
1425
1426         /* If socket state is TCP_LISTEN it cannot change (for now...),
1427          * so that no locks are necessary.
1428          */
1429
1430         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1431         if (!skb) {
1432                 /* This means receive shutdown. */
1433                 if (err == 0)
1434                         err = -EINVAL;
1435                 goto out;
1436         }
1437
1438         tsk = skb->sk;
1439         skb_free_datagram(sk, skb);
1440         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1441
1442         /* attach accepted sock to socket */
1443         unix_state_lock(tsk);
1444         newsock->state = SS_CONNECTED;
1445         unix_sock_inherit_flags(sock, newsock);
1446         sock_graft(tsk, newsock);
1447         unix_state_unlock(tsk);
1448         return 0;
1449
1450 out:
1451         return err;
1452 }
1453
1454
1455 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1456 {
1457         struct sock *sk = sock->sk;
1458         struct unix_sock *u;
1459         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1460         int err = 0;
1461
1462         if (peer) {
1463                 sk = unix_peer_get(sk);
1464
1465                 err = -ENOTCONN;
1466                 if (!sk)
1467                         goto out;
1468                 err = 0;
1469         } else {
1470                 sock_hold(sk);
1471         }
1472
1473         u = unix_sk(sk);
1474         unix_state_lock(sk);
1475         if (!u->addr) {
1476                 sunaddr->sun_family = AF_UNIX;
1477                 sunaddr->sun_path[0] = 0;
1478                 *uaddr_len = sizeof(short);
1479         } else {
1480                 struct unix_address *addr = u->addr;
1481
1482                 *uaddr_len = addr->len;
1483                 memcpy(sunaddr, addr->name, *uaddr_len);
1484         }
1485         unix_state_unlock(sk);
1486         sock_put(sk);
1487 out:
1488         return err;
1489 }
1490
1491 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1492 {
1493         int i;
1494
1495         scm->fp = UNIXCB(skb).fp;
1496         UNIXCB(skb).fp = NULL;
1497
1498         for (i = scm->fp->count-1; i >= 0; i--)
1499                 unix_notinflight(scm->fp->fp[i]);
1500 }
1501
1502 static void unix_destruct_scm(struct sk_buff *skb)
1503 {
1504         struct scm_cookie scm;
1505         memset(&scm, 0, sizeof(scm));
1506         scm.pid  = UNIXCB(skb).pid;
1507         if (UNIXCB(skb).fp)
1508                 unix_detach_fds(&scm, skb);
1509
1510         /* Alas, it calls VFS */
1511         /* So fscking what? fput() had been SMP-safe since the last Summer */
1512         scm_destroy(&scm);
1513         sock_wfree(skb);
1514 }
1515
1516 /*
1517  * The "user->unix_inflight" variable is protected by the garbage
1518  * collection lock, and we just read it locklessly here. If you go
1519  * over the limit, there might be a tiny race in actually noticing
1520  * it across threads. Tough.
1521  */
1522 static inline bool too_many_unix_fds(struct task_struct *p)
1523 {
1524         struct user_struct *user = current_user();
1525
1526         if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
1527                 return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
1528         return false;
1529 }
1530
1531 #define MAX_RECURSION_LEVEL 4
1532
1533 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1534 {
1535         int i;
1536         unsigned char max_level = 0;
1537         int unix_sock_count = 0;
1538
1539         if (too_many_unix_fds(current))
1540                 return -ETOOMANYREFS;
1541
1542         for (i = scm->fp->count - 1; i >= 0; i--) {
1543                 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1544
1545                 if (sk) {
1546                         unix_sock_count++;
1547                         max_level = max(max_level,
1548                                         unix_sk(sk)->recursion_level);
1549                 }
1550         }
1551         if (unlikely(max_level > MAX_RECURSION_LEVEL))
1552                 return -ETOOMANYREFS;
1553
1554         /*
1555          * Need to duplicate file references for the sake of garbage
1556          * collection.  Otherwise a socket in the fps might become a
1557          * candidate for GC while the skb is not yet queued.
1558          */
1559         UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1560         if (!UNIXCB(skb).fp)
1561                 return -ENOMEM;
1562
1563         for (i = scm->fp->count - 1; i >= 0; i--)
1564                 unix_inflight(scm->fp->fp[i]);
1565         return max_level;
1566 }
1567
1568 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1569 {
1570         int err = 0;
1571
1572         UNIXCB(skb).pid  = get_pid(scm->pid);
1573         UNIXCB(skb).uid = scm->creds.uid;
1574         UNIXCB(skb).gid = scm->creds.gid;
1575         UNIXCB(skb).fp = NULL;
1576         unix_get_secdata(scm, skb);
1577         if (scm->fp && send_fds)
1578                 err = unix_attach_fds(scm, skb);
1579
1580         skb->destructor = unix_destruct_scm;
1581         return err;
1582 }
1583
1584 static bool unix_passcred_enabled(const struct socket *sock,
1585                                   const struct sock *other)
1586 {
1587         return test_bit(SOCK_PASSCRED, &sock->flags) ||
1588                !other->sk_socket ||
1589                test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
1590 }
1591
1592 /*
1593  * Some apps rely on write() giving SCM_CREDENTIALS
1594  * We include credentials if source or destination socket
1595  * asserted SOCK_PASSCRED.
1596  */
1597 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
1598                             const struct sock *other)
1599 {
1600         if (UNIXCB(skb).pid)
1601                 return;
1602         if (unix_passcred_enabled(sock, other)) {
1603                 UNIXCB(skb).pid  = get_pid(task_tgid(current));
1604                 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1605         }
1606 }
1607
1608 static int maybe_init_creds(struct scm_cookie *scm,
1609                             struct socket *socket,
1610                             const struct sock *other)
1611 {
1612         int err;
1613         struct msghdr msg = { .msg_controllen = 0 };
1614
1615         err = scm_send(socket, &msg, scm, false);
1616         if (err)
1617                 return err;
1618
1619         if (unix_passcred_enabled(socket, other)) {
1620                 scm->pid = get_pid(task_tgid(current));
1621                 current_uid_gid(&scm->creds.uid, &scm->creds.gid);
1622         }
1623         return err;
1624 }
1625
1626 static bool unix_skb_scm_eq(struct sk_buff *skb,
1627                             struct scm_cookie *scm)
1628 {
1629         const struct unix_skb_parms *u = &UNIXCB(skb);
1630
1631         return u->pid == scm->pid &&
1632                uid_eq(u->uid, scm->creds.uid) &&
1633                gid_eq(u->gid, scm->creds.gid) &&
1634                unix_secdata_eq(scm, skb);
1635 }
1636
1637 /*
1638  *      Send AF_UNIX data.
1639  */
1640
1641 static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
1642                               size_t len)
1643 {
1644         struct sock *sk = sock->sk;
1645         struct net *net = sock_net(sk);
1646         struct unix_sock *u = unix_sk(sk);
1647         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
1648         struct sock *other = NULL;
1649         int namelen = 0; /* fake GCC */
1650         int err;
1651         unsigned int hash;
1652         struct sk_buff *skb;
1653         long timeo;
1654         struct scm_cookie scm;
1655         int max_level;
1656         int data_len = 0;
1657         int sk_locked;
1658
1659         wait_for_unix_gc();
1660         err = scm_send(sock, msg, &scm, false);
1661         if (err < 0)
1662                 return err;
1663
1664         err = -EOPNOTSUPP;
1665         if (msg->msg_flags&MSG_OOB)
1666                 goto out;
1667
1668         if (msg->msg_namelen) {
1669                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1670                 if (err < 0)
1671                         goto out;
1672                 namelen = err;
1673         } else {
1674                 sunaddr = NULL;
1675                 err = -ENOTCONN;
1676                 other = unix_peer_get(sk);
1677                 if (!other)
1678                         goto out;
1679         }
1680
1681         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1682             && (err = unix_autobind(sock)) != 0)
1683                 goto out;
1684
1685         err = -EMSGSIZE;
1686         if (len > sk->sk_sndbuf - 32)
1687                 goto out;
1688
1689         if (len > SKB_MAX_ALLOC) {
1690                 data_len = min_t(size_t,
1691                                  len - SKB_MAX_ALLOC,
1692                                  MAX_SKB_FRAGS * PAGE_SIZE);
1693                 data_len = PAGE_ALIGN(data_len);
1694
1695                 BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
1696         }
1697
1698         skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1699                                    msg->msg_flags & MSG_DONTWAIT, &err,
1700                                    PAGE_ALLOC_COSTLY_ORDER);
1701         if (skb == NULL)
1702                 goto out;
1703
1704         err = unix_scm_to_skb(&scm, skb, true);
1705         if (err < 0)
1706                 goto out_free;
1707         max_level = err + 1;
1708
1709         skb_put(skb, len - data_len);
1710         skb->data_len = data_len;
1711         skb->len = len;
1712         err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
1713         if (err)
1714                 goto out_free;
1715
1716         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1717
1718 restart:
1719         if (!other) {
1720                 err = -ECONNRESET;
1721                 if (sunaddr == NULL)
1722                         goto out_free;
1723
1724                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1725                                         hash, &err);
1726                 if (other == NULL)
1727                         goto out_free;
1728         }
1729
1730         if (sk_filter(other, skb) < 0) {
1731                 /* Toss the packet but do not return any error to the sender */
1732                 err = len;
1733                 goto out_free;
1734         }
1735
1736         sk_locked = 0;
1737         unix_state_lock(other);
1738 restart_locked:
1739         err = -EPERM;
1740         if (!unix_may_send(sk, other))
1741                 goto out_unlock;
1742
1743         if (unlikely(sock_flag(other, SOCK_DEAD))) {
1744                 /*
1745                  *      Check with 1003.1g - what should
1746                  *      datagram error
1747                  */
1748                 unix_state_unlock(other);
1749                 sock_put(other);
1750
1751                 if (!sk_locked)
1752                         unix_state_lock(sk);
1753
1754                 err = 0;
1755                 if (unix_peer(sk) == other) {
1756                         unix_peer(sk) = NULL;
1757                         unix_dgram_peer_wake_disconnect_wakeup(sk, other);
1758
1759                         unix_state_unlock(sk);
1760
1761                         unix_dgram_disconnected(sk, other);
1762                         sock_put(other);
1763                         err = -ECONNREFUSED;
1764                 } else {
1765                         unix_state_unlock(sk);
1766                 }
1767
1768                 other = NULL;
1769                 if (err)
1770                         goto out_free;
1771                 goto restart;
1772         }
1773
1774         err = -EPIPE;
1775         if (other->sk_shutdown & RCV_SHUTDOWN)
1776                 goto out_unlock;
1777
1778         if (sk->sk_type != SOCK_SEQPACKET) {
1779                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1780                 if (err)
1781                         goto out_unlock;
1782         }
1783
1784         if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1785                 if (timeo) {
1786                         timeo = unix_wait_for_peer(other, timeo);
1787
1788                         err = sock_intr_errno(timeo);
1789                         if (signal_pending(current))
1790                                 goto out_free;
1791
1792                         goto restart;
1793                 }
1794
1795                 if (!sk_locked) {
1796                         unix_state_unlock(other);
1797                         unix_state_double_lock(sk, other);
1798                 }
1799
1800                 if (unix_peer(sk) != other ||
1801                     unix_dgram_peer_wake_me(sk, other)) {
1802                         err = -EAGAIN;
1803                         sk_locked = 1;
1804                         goto out_unlock;
1805                 }
1806
1807                 if (!sk_locked) {
1808                         sk_locked = 1;
1809                         goto restart_locked;
1810                 }
1811         }
1812
1813         if (unlikely(sk_locked))
1814                 unix_state_unlock(sk);
1815
1816         if (sock_flag(other, SOCK_RCVTSTAMP))
1817                 __net_timestamp(skb);
1818         maybe_add_creds(skb, sock, other);
1819         skb_queue_tail(&other->sk_receive_queue, skb);
1820         if (max_level > unix_sk(other)->recursion_level)
1821                 unix_sk(other)->recursion_level = max_level;
1822         unix_state_unlock(other);
1823         other->sk_data_ready(other);
1824         sock_put(other);
1825         scm_destroy(&scm);
1826         return len;
1827
1828 out_unlock:
1829         if (sk_locked)
1830                 unix_state_unlock(sk);
1831         unix_state_unlock(other);
1832 out_free:
1833         kfree_skb(skb);
1834 out:
1835         if (other)
1836                 sock_put(other);
1837         scm_destroy(&scm);
1838         return err;
1839 }
1840
1841 /* We use paged skbs for stream sockets, and limit occupancy to 32768
1842  * bytes, and a minimun of a full page.
1843  */
1844 #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1845
1846 static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
1847                                size_t len)
1848 {
1849         struct sock *sk = sock->sk;
1850         struct sock *other = NULL;
1851         int err, size;
1852         struct sk_buff *skb;
1853         int sent = 0;
1854         struct scm_cookie scm;
1855         bool fds_sent = false;
1856         int max_level;
1857         int data_len;
1858
1859         wait_for_unix_gc();
1860         err = scm_send(sock, msg, &scm, false);
1861         if (err < 0)
1862                 return err;
1863
1864         err = -EOPNOTSUPP;
1865         if (msg->msg_flags&MSG_OOB)
1866                 goto out_err;
1867
1868         if (msg->msg_namelen) {
1869                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1870                 goto out_err;
1871         } else {
1872                 err = -ENOTCONN;
1873                 other = unix_peer(sk);
1874                 if (!other)
1875                         goto out_err;
1876         }
1877
1878         if (sk->sk_shutdown & SEND_SHUTDOWN)
1879                 goto pipe_err;
1880
1881         while (sent < len) {
1882                 size = len - sent;
1883
1884                 /* Keep two messages in the pipe so it schedules better */
1885                 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
1886
1887                 /* allow fallback to order-0 allocations */
1888                 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1889
1890                 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
1891
1892                 data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
1893
1894                 skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1895                                            msg->msg_flags & MSG_DONTWAIT, &err,
1896                                            get_order(UNIX_SKB_FRAGS_SZ));
1897                 if (!skb)
1898                         goto out_err;
1899
1900                 /* Only send the fds in the first buffer */
1901                 err = unix_scm_to_skb(&scm, skb, !fds_sent);
1902                 if (err < 0) {
1903                         kfree_skb(skb);
1904                         goto out_err;
1905                 }
1906                 max_level = err + 1;
1907                 fds_sent = true;
1908
1909                 skb_put(skb, size - data_len);
1910                 skb->data_len = data_len;
1911                 skb->len = size;
1912                 err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
1913                 if (err) {
1914                         kfree_skb(skb);
1915                         goto out_err;
1916                 }
1917
1918                 unix_state_lock(other);
1919
1920                 if (sock_flag(other, SOCK_DEAD) ||
1921                     (other->sk_shutdown & RCV_SHUTDOWN))
1922                         goto pipe_err_free;
1923
1924                 maybe_add_creds(skb, sock, other);
1925                 skb_queue_tail(&other->sk_receive_queue, skb);
1926                 if (max_level > unix_sk(other)->recursion_level)
1927                         unix_sk(other)->recursion_level = max_level;
1928                 unix_state_unlock(other);
1929                 other->sk_data_ready(other);
1930                 sent += size;
1931         }
1932
1933         scm_destroy(&scm);
1934
1935         return sent;
1936
1937 pipe_err_free:
1938         unix_state_unlock(other);
1939         kfree_skb(skb);
1940 pipe_err:
1941         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1942                 send_sig(SIGPIPE, current, 0);
1943         err = -EPIPE;
1944 out_err:
1945         scm_destroy(&scm);
1946         return sent ? : err;
1947 }
1948
1949 static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
1950                                     int offset, size_t size, int flags)
1951 {
1952         int err;
1953         bool send_sigpipe = false;
1954         bool init_scm = true;
1955         struct scm_cookie scm;
1956         struct sock *other, *sk = socket->sk;
1957         struct sk_buff *skb, *newskb = NULL, *tail = NULL;
1958
1959         if (flags & MSG_OOB)
1960                 return -EOPNOTSUPP;
1961
1962         other = unix_peer(sk);
1963         if (!other || sk->sk_state != TCP_ESTABLISHED)
1964                 return -ENOTCONN;
1965
1966         if (false) {
1967 alloc_skb:
1968                 unix_state_unlock(other);
1969                 mutex_unlock(&unix_sk(other)->readlock);
1970                 newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
1971                                               &err, 0);
1972                 if (!newskb)
1973                         goto err;
1974         }
1975
1976         /* we must acquire readlock as we modify already present
1977          * skbs in the sk_receive_queue and mess with skb->len
1978          */
1979         err = mutex_lock_interruptible(&unix_sk(other)->readlock);
1980         if (err) {
1981                 err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
1982                 goto err;
1983         }
1984
1985         if (sk->sk_shutdown & SEND_SHUTDOWN) {
1986                 err = -EPIPE;
1987                 send_sigpipe = true;
1988                 goto err_unlock;
1989         }
1990
1991         unix_state_lock(other);
1992
1993         if (sock_flag(other, SOCK_DEAD) ||
1994             other->sk_shutdown & RCV_SHUTDOWN) {
1995                 err = -EPIPE;
1996                 send_sigpipe = true;
1997                 goto err_state_unlock;
1998         }
1999
2000         if (init_scm) {
2001                 err = maybe_init_creds(&scm, socket, other);
2002                 if (err)
2003                         goto err_state_unlock;
2004                 init_scm = false;
2005         }
2006
2007         skb = skb_peek_tail(&other->sk_receive_queue);
2008         if (tail && tail == skb) {
2009                 skb = newskb;
2010         } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
2011                 if (newskb) {
2012                         skb = newskb;
2013                 } else {
2014                         tail = skb;
2015                         goto alloc_skb;
2016                 }
2017         } else if (newskb) {
2018                 /* this is fast path, we don't necessarily need to
2019                  * call to kfree_skb even though with newskb == NULL
2020                  * this - does no harm
2021                  */
2022                 consume_skb(newskb);
2023                 newskb = NULL;
2024         }
2025
2026         if (skb_append_pagefrags(skb, page, offset, size)) {
2027                 tail = skb;
2028                 goto alloc_skb;
2029         }
2030
2031         skb->len += size;
2032         skb->data_len += size;
2033         skb->truesize += size;
2034         atomic_add(size, &sk->sk_wmem_alloc);
2035
2036         if (newskb) {
2037                 err = unix_scm_to_skb(&scm, skb, false);
2038                 if (err)
2039                         goto err_state_unlock;
2040                 spin_lock(&other->sk_receive_queue.lock);
2041                 __skb_queue_tail(&other->sk_receive_queue, newskb);
2042                 spin_unlock(&other->sk_receive_queue.lock);
2043         }
2044
2045         unix_state_unlock(other);
2046         mutex_unlock(&unix_sk(other)->readlock);
2047
2048         other->sk_data_ready(other);
2049         scm_destroy(&scm);
2050         return size;
2051
2052 err_state_unlock:
2053         unix_state_unlock(other);
2054 err_unlock:
2055         mutex_unlock(&unix_sk(other)->readlock);
2056 err:
2057         kfree_skb(newskb);
2058         if (send_sigpipe && !(flags & MSG_NOSIGNAL))
2059                 send_sig(SIGPIPE, current, 0);
2060         if (!init_scm)
2061                 scm_destroy(&scm);
2062         return err;
2063 }
2064
2065 static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
2066                                   size_t len)
2067 {
2068         int err;
2069         struct sock *sk = sock->sk;
2070
2071         err = sock_error(sk);
2072         if (err)
2073                 return err;
2074
2075         if (sk->sk_state != TCP_ESTABLISHED)
2076                 return -ENOTCONN;
2077
2078         if (msg->msg_namelen)
2079                 msg->msg_namelen = 0;
2080
2081         return unix_dgram_sendmsg(sock, msg, len);
2082 }
2083
2084 static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
2085                                   size_t size, int flags)
2086 {
2087         struct sock *sk = sock->sk;
2088
2089         if (sk->sk_state != TCP_ESTABLISHED)
2090                 return -ENOTCONN;
2091
2092         return unix_dgram_recvmsg(sock, msg, size, flags);
2093 }
2094
2095 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
2096 {
2097         struct unix_sock *u = unix_sk(sk);
2098
2099         if (u->addr) {
2100                 msg->msg_namelen = u->addr->len;
2101                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
2102         }
2103 }
2104
2105 static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
2106                               size_t size, int flags)
2107 {
2108         struct scm_cookie scm;
2109         struct sock *sk = sock->sk;
2110         struct unix_sock *u = unix_sk(sk);
2111         struct sk_buff *skb, *last;
2112         long timeo;
2113         int err;
2114         int peeked, skip;
2115
2116         err = -EOPNOTSUPP;
2117         if (flags&MSG_OOB)
2118                 goto out;
2119
2120         timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
2121
2122         do {
2123                 mutex_lock(&u->readlock);
2124
2125                 skip = sk_peek_offset(sk, flags);
2126                 skb = __skb_try_recv_datagram(sk, flags, &peeked, &skip, &err,
2127                                               &last);
2128                 if (skb)
2129                         break;
2130
2131                 mutex_unlock(&u->readlock);
2132
2133                 if (err != -EAGAIN)
2134                         break;
2135         } while (timeo &&
2136                  !__skb_wait_for_more_packets(sk, &err, &timeo, last));
2137
2138         if (!skb) { /* implies readlock unlocked */
2139                 unix_state_lock(sk);
2140                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
2141                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
2142                     (sk->sk_shutdown & RCV_SHUTDOWN))
2143                         err = 0;
2144                 unix_state_unlock(sk);
2145                 goto out;
2146         }
2147
2148         if (wq_has_sleeper(&u->peer_wait))
2149                 wake_up_interruptible_sync_poll(&u->peer_wait,
2150                                                 POLLOUT | POLLWRNORM |
2151                                                 POLLWRBAND);
2152
2153         if (msg->msg_name)
2154                 unix_copy_addr(msg, skb->sk);
2155
2156         if (size > skb->len - skip)
2157                 size = skb->len - skip;
2158         else if (size < skb->len - skip)
2159                 msg->msg_flags |= MSG_TRUNC;
2160
2161         err = skb_copy_datagram_msg(skb, skip, msg, size);
2162         if (err)
2163                 goto out_free;
2164
2165         if (sock_flag(sk, SOCK_RCVTSTAMP))
2166                 __sock_recv_timestamp(msg, sk, skb);
2167
2168         memset(&scm, 0, sizeof(scm));
2169
2170         scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2171         unix_set_secdata(&scm, skb);
2172
2173         if (!(flags & MSG_PEEK)) {
2174                 if (UNIXCB(skb).fp)
2175                         unix_detach_fds(&scm, skb);
2176
2177                 sk_peek_offset_bwd(sk, skb->len);
2178         } else {
2179                 /* It is questionable: on PEEK we could:
2180                    - do not return fds - good, but too simple 8)
2181                    - return fds, and do not return them on read (old strategy,
2182                      apparently wrong)
2183                    - clone fds (I chose it for now, it is the most universal
2184                      solution)
2185
2186                    POSIX 1003.1g does not actually define this clearly
2187                    at all. POSIX 1003.1g doesn't define a lot of things
2188                    clearly however!
2189
2190                 */
2191
2192                 sk_peek_offset_fwd(sk, size);
2193
2194                 if (UNIXCB(skb).fp)
2195                         scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2196         }
2197         err = (flags & MSG_TRUNC) ? skb->len - skip : size;
2198
2199         scm_recv(sock, msg, &scm, flags);
2200
2201 out_free:
2202         skb_free_datagram(sk, skb);
2203         mutex_unlock(&u->readlock);
2204 out:
2205         return err;
2206 }
2207
2208 /*
2209  *      Sleep until more data has arrived. But check for races..
2210  */
2211 static long unix_stream_data_wait(struct sock *sk, long timeo,
2212                                   struct sk_buff *last, unsigned int last_len)
2213 {
2214         struct sk_buff *tail;
2215         DEFINE_WAIT(wait);
2216
2217         unix_state_lock(sk);
2218
2219         for (;;) {
2220                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
2221
2222                 tail = skb_peek_tail(&sk->sk_receive_queue);
2223                 if (tail != last ||
2224                     (tail && tail->len != last_len) ||
2225                     sk->sk_err ||
2226                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
2227                     signal_pending(current) ||
2228                     !timeo)
2229                         break;
2230
2231                 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2232                 unix_state_unlock(sk);
2233                 timeo = freezable_schedule_timeout(timeo);
2234                 unix_state_lock(sk);
2235
2236                 if (sock_flag(sk, SOCK_DEAD))
2237                         break;
2238
2239                 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2240         }
2241
2242         finish_wait(sk_sleep(sk), &wait);
2243         unix_state_unlock(sk);
2244         return timeo;
2245 }
2246
2247 static unsigned int unix_skb_len(const struct sk_buff *skb)
2248 {
2249         return skb->len - UNIXCB(skb).consumed;
2250 }
2251
2252 struct unix_stream_read_state {
2253         int (*recv_actor)(struct sk_buff *, int, int,
2254                           struct unix_stream_read_state *);
2255         struct socket *socket;
2256         struct msghdr *msg;
2257         struct pipe_inode_info *pipe;
2258         size_t size;
2259         int flags;
2260         unsigned int splice_flags;
2261 };
2262
2263 static int unix_stream_read_generic(struct unix_stream_read_state *state)
2264 {
2265         struct scm_cookie scm;
2266         struct socket *sock = state->socket;
2267         struct sock *sk = sock->sk;
2268         struct unix_sock *u = unix_sk(sk);
2269         int copied = 0;
2270         int flags = state->flags;
2271         int noblock = flags & MSG_DONTWAIT;
2272         bool check_creds = false;
2273         int target;
2274         int err = 0;
2275         long timeo;
2276         int skip;
2277         size_t size = state->size;
2278         unsigned int last_len;
2279
2280         err = -EINVAL;
2281         if (sk->sk_state != TCP_ESTABLISHED)
2282                 goto out;
2283
2284         err = -EOPNOTSUPP;
2285         if (flags & MSG_OOB)
2286                 goto out;
2287
2288         target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2289         timeo = sock_rcvtimeo(sk, noblock);
2290
2291         memset(&scm, 0, sizeof(scm));
2292
2293         /* Lock the socket to prevent queue disordering
2294          * while sleeps in memcpy_tomsg
2295          */
2296         mutex_lock(&u->readlock);
2297
2298         if (flags & MSG_PEEK)
2299                 skip = sk_peek_offset(sk, flags);
2300         else
2301                 skip = 0;
2302
2303         do {
2304                 int chunk;
2305                 bool drop_skb;
2306                 struct sk_buff *skb, *last;
2307
2308                 unix_state_lock(sk);
2309                 if (sock_flag(sk, SOCK_DEAD)) {
2310                         err = -ECONNRESET;
2311                         goto unlock;
2312                 }
2313                 last = skb = skb_peek(&sk->sk_receive_queue);
2314                 last_len = last ? last->len : 0;
2315 again:
2316                 if (skb == NULL) {
2317                         unix_sk(sk)->recursion_level = 0;
2318                         if (copied >= target)
2319                                 goto unlock;
2320
2321                         /*
2322                          *      POSIX 1003.1g mandates this order.
2323                          */
2324
2325                         err = sock_error(sk);
2326                         if (err)
2327                                 goto unlock;
2328                         if (sk->sk_shutdown & RCV_SHUTDOWN)
2329                                 goto unlock;
2330
2331                         unix_state_unlock(sk);
2332                         err = -EAGAIN;
2333                         if (!timeo)
2334                                 break;
2335                         mutex_unlock(&u->readlock);
2336
2337                         timeo = unix_stream_data_wait(sk, timeo, last,
2338                                                       last_len);
2339
2340                         if (signal_pending(current)) {
2341                                 err = sock_intr_errno(timeo);
2342                                 goto out;
2343                         }
2344
2345                         mutex_lock(&u->readlock);
2346                         continue;
2347 unlock:
2348                         unix_state_unlock(sk);
2349                         break;
2350                 }
2351
2352                 while (skip >= unix_skb_len(skb)) {
2353                         skip -= unix_skb_len(skb);
2354                         last = skb;
2355                         last_len = skb->len;
2356                         skb = skb_peek_next(skb, &sk->sk_receive_queue);
2357                         if (!skb)
2358                                 goto again;
2359                 }
2360
2361                 unix_state_unlock(sk);
2362
2363                 if (check_creds) {
2364                         /* Never glue messages from different writers */
2365                         if (!unix_skb_scm_eq(skb, &scm))
2366                                 break;
2367                 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
2368                         /* Copy credentials */
2369                         scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2370                         unix_set_secdata(&scm, skb);
2371                         check_creds = true;
2372                 }
2373
2374                 /* Copy address just once */
2375                 if (state->msg && state->msg->msg_name) {
2376                         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
2377                                          state->msg->msg_name);
2378                         unix_copy_addr(state->msg, skb->sk);
2379                         sunaddr = NULL;
2380                 }
2381
2382                 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2383                 skb_get(skb);
2384                 chunk = state->recv_actor(skb, skip, chunk, state);
2385                 drop_skb = !unix_skb_len(skb);
2386                 /* skb is only safe to use if !drop_skb */
2387                 consume_skb(skb);
2388                 if (chunk < 0) {
2389                         if (copied == 0)
2390                                 copied = -EFAULT;
2391                         break;
2392                 }
2393                 copied += chunk;
2394                 size -= chunk;
2395
2396                 if (drop_skb) {
2397                         /* the skb was touched by a concurrent reader;
2398                          * we should not expect anything from this skb
2399                          * anymore and assume it invalid - we can be
2400                          * sure it was dropped from the socket queue
2401                          *
2402                          * let's report a short read
2403                          */
2404                         err = 0;
2405                         break;
2406                 }
2407
2408                 /* Mark read part of skb as used */
2409                 if (!(flags & MSG_PEEK)) {
2410                         UNIXCB(skb).consumed += chunk;
2411
2412                         sk_peek_offset_bwd(sk, chunk);
2413
2414                         if (UNIXCB(skb).fp)
2415                                 unix_detach_fds(&scm, skb);
2416
2417                         if (unix_skb_len(skb))
2418                                 break;
2419
2420                         skb_unlink(skb, &sk->sk_receive_queue);
2421                         consume_skb(skb);
2422
2423                         if (scm.fp)
2424                                 break;
2425                 } else {
2426                         /* It is questionable, see note in unix_dgram_recvmsg.
2427                          */
2428                         if (UNIXCB(skb).fp)
2429                                 scm.fp = scm_fp_dup(UNIXCB(skb).fp);
2430
2431                         sk_peek_offset_fwd(sk, chunk);
2432
2433                         if (UNIXCB(skb).fp)
2434                                 break;
2435
2436                         skip = 0;
2437                         last = skb;
2438                         last_len = skb->len;
2439                         unix_state_lock(sk);
2440                         skb = skb_peek_next(skb, &sk->sk_receive_queue);
2441                         if (skb)
2442                                 goto again;
2443                         unix_state_unlock(sk);
2444                         break;
2445                 }
2446         } while (size);
2447
2448         mutex_unlock(&u->readlock);
2449         if (state->msg)
2450                 scm_recv(sock, state->msg, &scm, flags);
2451         else
2452                 scm_destroy(&scm);
2453 out:
2454         return copied ? : err;
2455 }
2456
2457 static int unix_stream_read_actor(struct sk_buff *skb,
2458                                   int skip, int chunk,
2459                                   struct unix_stream_read_state *state)
2460 {
2461         int ret;
2462
2463         ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
2464                                     state->msg, chunk);
2465         return ret ?: chunk;
2466 }
2467
2468 static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
2469                                size_t size, int flags)
2470 {
2471         struct unix_stream_read_state state = {
2472                 .recv_actor = unix_stream_read_actor,
2473                 .socket = sock,
2474                 .msg = msg,
2475                 .size = size,
2476                 .flags = flags
2477         };
2478
2479         return unix_stream_read_generic(&state);
2480 }
2481
2482 static ssize_t skb_unix_socket_splice(struct sock *sk,
2483                                       struct pipe_inode_info *pipe,
2484                                       struct splice_pipe_desc *spd)
2485 {
2486         int ret;
2487         struct unix_sock *u = unix_sk(sk);
2488
2489         mutex_unlock(&u->readlock);
2490         ret = splice_to_pipe(pipe, spd);
2491         mutex_lock(&u->readlock);
2492
2493         return ret;
2494 }
2495
2496 static int unix_stream_splice_actor(struct sk_buff *skb,
2497                                     int skip, int chunk,
2498                                     struct unix_stream_read_state *state)
2499 {
2500         return skb_splice_bits(skb, state->socket->sk,
2501                                UNIXCB(skb).consumed + skip,
2502                                state->pipe, chunk, state->splice_flags,
2503                                skb_unix_socket_splice);
2504 }
2505
2506 static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,
2507                                        struct pipe_inode_info *pipe,
2508                                        size_t size, unsigned int flags)
2509 {
2510         struct unix_stream_read_state state = {
2511                 .recv_actor = unix_stream_splice_actor,
2512                 .socket = sock,
2513                 .pipe = pipe,
2514                 .size = size,
2515                 .splice_flags = flags,
2516         };
2517
2518         if (unlikely(*ppos))
2519                 return -ESPIPE;
2520
2521         if (sock->file->f_flags & O_NONBLOCK ||
2522             flags & SPLICE_F_NONBLOCK)
2523                 state.flags = MSG_DONTWAIT;
2524
2525         return unix_stream_read_generic(&state);
2526 }
2527
2528 static int unix_shutdown(struct socket *sock, int mode)
2529 {
2530         struct sock *sk = sock->sk;
2531         struct sock *other;
2532
2533         if (mode < SHUT_RD || mode > SHUT_RDWR)
2534                 return -EINVAL;
2535         /* This maps:
2536          * SHUT_RD   (0) -> RCV_SHUTDOWN  (1)
2537          * SHUT_WR   (1) -> SEND_SHUTDOWN (2)
2538          * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
2539          */
2540         ++mode;
2541
2542         unix_state_lock(sk);
2543         sk->sk_shutdown |= mode;
2544         other = unix_peer(sk);
2545         if (other)
2546                 sock_hold(other);
2547         unix_state_unlock(sk);
2548         sk->sk_state_change(sk);
2549
2550         if (other &&
2551                 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2552
2553                 int peer_mode = 0;
2554
2555                 if (mode&RCV_SHUTDOWN)
2556                         peer_mode |= SEND_SHUTDOWN;
2557                 if (mode&SEND_SHUTDOWN)
2558                         peer_mode |= RCV_SHUTDOWN;
2559                 unix_state_lock(other);
2560                 other->sk_shutdown |= peer_mode;
2561                 unix_state_unlock(other);
2562                 other->sk_state_change(other);
2563                 if (peer_mode == SHUTDOWN_MASK)
2564                         sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2565                 else if (peer_mode & RCV_SHUTDOWN)
2566                         sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2567         }
2568         if (other)
2569                 sock_put(other);
2570
2571         return 0;
2572 }
2573
2574 long unix_inq_len(struct sock *sk)
2575 {
2576         struct sk_buff *skb;
2577         long amount = 0;
2578
2579         if (sk->sk_state == TCP_LISTEN)
2580                 return -EINVAL;
2581
2582         spin_lock(&sk->sk_receive_queue.lock);
2583         if (sk->sk_type == SOCK_STREAM ||
2584             sk->sk_type == SOCK_SEQPACKET) {
2585                 skb_queue_walk(&sk->sk_receive_queue, skb)
2586                         amount += unix_skb_len(skb);
2587         } else {
2588                 skb = skb_peek(&sk->sk_receive_queue);
2589                 if (skb)
2590                         amount = skb->len;
2591         }
2592         spin_unlock(&sk->sk_receive_queue.lock);
2593
2594         return amount;
2595 }
2596 EXPORT_SYMBOL_GPL(unix_inq_len);
2597
2598 long unix_outq_len(struct sock *sk)
2599 {
2600         return sk_wmem_alloc_get(sk);
2601 }
2602 EXPORT_SYMBOL_GPL(unix_outq_len);
2603
2604 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2605 {
2606         struct sock *sk = sock->sk;
2607         long amount = 0;
2608         int err;
2609
2610         switch (cmd) {
2611         case SIOCOUTQ:
2612                 amount = unix_outq_len(sk);
2613                 err = put_user(amount, (int __user *)arg);
2614                 break;
2615         case SIOCINQ:
2616                 amount = unix_inq_len(sk);
2617                 if (amount < 0)
2618                         err = amount;
2619                 else
2620                         err = put_user(amount, (int __user *)arg);
2621                 break;
2622         default:
2623                 err = -ENOIOCTLCMD;
2624                 break;
2625         }
2626         return err;
2627 }
2628
2629 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2630 {
2631         struct sock *sk = sock->sk;
2632         unsigned int mask;
2633
2634         sock_poll_wait(file, sk_sleep(sk), wait);
2635         mask = 0;
2636
2637         /* exceptional events? */
2638         if (sk->sk_err)
2639                 mask |= POLLERR;
2640         if (sk->sk_shutdown == SHUTDOWN_MASK)
2641                 mask |= POLLHUP;
2642         if (sk->sk_shutdown & RCV_SHUTDOWN)
2643                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2644
2645         /* readable? */
2646         if (!skb_queue_empty(&sk->sk_receive_queue))
2647                 mask |= POLLIN | POLLRDNORM;
2648
2649         /* Connection-based need to check for termination and startup */
2650         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2651             sk->sk_state == TCP_CLOSE)
2652                 mask |= POLLHUP;
2653
2654         /*
2655          * we set writable also when the other side has shut down the
2656          * connection. This prevents stuck sockets.
2657          */
2658         if (unix_writable(sk))
2659                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2660
2661         return mask;
2662 }
2663
2664 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2665                                     poll_table *wait)
2666 {
2667         struct sock *sk = sock->sk, *other;
2668         unsigned int mask, writable;
2669
2670         sock_poll_wait(file, sk_sleep(sk), wait);
2671         mask = 0;
2672
2673         /* exceptional events? */
2674         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2675                 mask |= POLLERR |
2676                         (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2677
2678         if (sk->sk_shutdown & RCV_SHUTDOWN)
2679                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2680         if (sk->sk_shutdown == SHUTDOWN_MASK)
2681                 mask |= POLLHUP;
2682
2683         /* readable? */
2684         if (!skb_queue_empty(&sk->sk_receive_queue))
2685                 mask |= POLLIN | POLLRDNORM;
2686
2687         /* Connection-based need to check for termination and startup */
2688         if (sk->sk_type == SOCK_SEQPACKET) {
2689                 if (sk->sk_state == TCP_CLOSE)
2690                         mask |= POLLHUP;
2691                 /* connection hasn't started yet? */
2692                 if (sk->sk_state == TCP_SYN_SENT)
2693                         return mask;
2694         }
2695
2696         /* No write status requested, avoid expensive OUT tests. */
2697         if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
2698                 return mask;
2699
2700         writable = unix_writable(sk);
2701         if (writable) {
2702                 unix_state_lock(sk);
2703
2704                 other = unix_peer(sk);
2705                 if (other && unix_peer(other) != sk &&
2706                     unix_recvq_full(other) &&
2707                     unix_dgram_peer_wake_me(sk, other))
2708                         writable = 0;
2709
2710                 unix_state_unlock(sk);
2711         }
2712
2713         if (writable)
2714                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2715         else
2716                 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2717
2718         return mask;
2719 }
2720
2721 #ifdef CONFIG_PROC_FS
2722
2723 #define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)
2724
2725 #define get_bucket(x) ((x) >> BUCKET_SPACE)
2726 #define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
2727 #define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2728
2729 static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
2730 {
2731         unsigned long offset = get_offset(*pos);
2732         unsigned long bucket = get_bucket(*pos);
2733         struct sock *sk;
2734         unsigned long count = 0;
2735
2736         for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
2737                 if (sock_net(sk) != seq_file_net(seq))
2738                         continue;
2739                 if (++count == offset)
2740                         break;
2741         }
2742
2743         return sk;
2744 }
2745
2746 static struct sock *unix_next_socket(struct seq_file *seq,
2747                                      struct sock *sk,
2748                                      loff_t *pos)
2749 {
2750         unsigned long bucket;
2751
2752         while (sk > (struct sock *)SEQ_START_TOKEN) {
2753                 sk = sk_next(sk);
2754                 if (!sk)
2755                         goto next_bucket;
2756                 if (sock_net(sk) == seq_file_net(seq))
2757                         return sk;
2758         }
2759
2760         do {
2761                 sk = unix_from_bucket(seq, pos);
2762                 if (sk)
2763                         return sk;
2764
2765 next_bucket:
2766                 bucket = get_bucket(*pos) + 1;
2767                 *pos = set_bucket_offset(bucket, 1);
2768         } while (bucket < ARRAY_SIZE(unix_socket_table));
2769
2770         return NULL;
2771 }
2772
2773 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2774         __acquires(unix_table_lock)
2775 {
2776         spin_lock(&unix_table_lock);
2777
2778         if (!*pos)
2779                 return SEQ_START_TOKEN;
2780
2781         if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
2782                 return NULL;
2783
2784         return unix_next_socket(seq, NULL, pos);
2785 }
2786
2787 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2788 {
2789         ++*pos;
2790         return unix_next_socket(seq, v, pos);
2791 }
2792
2793 static void unix_seq_stop(struct seq_file *seq, void *v)
2794         __releases(unix_table_lock)
2795 {
2796         spin_unlock(&unix_table_lock);
2797 }
2798
2799 static int unix_seq_show(struct seq_file *seq, void *v)
2800 {
2801
2802         if (v == SEQ_START_TOKEN)
2803                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2804                          "Inode Path\n");
2805         else {
2806                 struct sock *s = v;
2807                 struct unix_sock *u = unix_sk(s);
2808                 unix_state_lock(s);
2809
2810                 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
2811                         s,
2812                         atomic_read(&s->sk_refcnt),
2813                         0,
2814                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2815                         s->sk_type,
2816                         s->sk_socket ?
2817                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2818                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2819                         sock_i_ino(s));
2820
2821                 if (u->addr) {
2822                         int i, len;
2823                         seq_putc(seq, ' ');
2824
2825                         i = 0;
2826                         len = u->addr->len - sizeof(short);
2827                         if (!UNIX_ABSTRACT(s))
2828                                 len--;
2829                         else {
2830                                 seq_putc(seq, '@');
2831                                 i++;
2832                         }
2833                         for ( ; i < len; i++)
2834                                 seq_putc(seq, u->addr->name->sun_path[i]);
2835                 }
2836                 unix_state_unlock(s);
2837                 seq_putc(seq, '\n');
2838         }
2839
2840         return 0;
2841 }
2842
2843 static const struct seq_operations unix_seq_ops = {
2844         .start  = unix_seq_start,
2845         .next   = unix_seq_next,
2846         .stop   = unix_seq_stop,
2847         .show   = unix_seq_show,
2848 };
2849
2850 static int unix_seq_open(struct inode *inode, struct file *file)
2851 {
2852         return seq_open_net(inode, file, &unix_seq_ops,
2853                             sizeof(struct seq_net_private));
2854 }
2855
2856 static const struct file_operations unix_seq_fops = {
2857         .owner          = THIS_MODULE,
2858         .open           = unix_seq_open,
2859         .read           = seq_read,
2860         .llseek         = seq_lseek,
2861         .release        = seq_release_net,
2862 };
2863
2864 #endif
2865
2866 static const struct net_proto_family unix_family_ops = {
2867         .family = PF_UNIX,
2868         .create = unix_create,
2869         .owner  = THIS_MODULE,
2870 };
2871
2872
2873 static int __net_init unix_net_init(struct net *net)
2874 {
2875         int error = -ENOMEM;
2876
2877         net->unx.sysctl_max_dgram_qlen = 10;
2878         if (unix_sysctl_register(net))
2879                 goto out;
2880
2881 #ifdef CONFIG_PROC_FS
2882         if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2883                 unix_sysctl_unregister(net);
2884                 goto out;
2885         }
2886 #endif
2887         error = 0;
2888 out:
2889         return error;
2890 }
2891
2892 static void __net_exit unix_net_exit(struct net *net)
2893 {
2894         unix_sysctl_unregister(net);
2895         remove_proc_entry("unix", net->proc_net);
2896 }
2897
2898 static struct pernet_operations unix_net_ops = {
2899         .init = unix_net_init,
2900         .exit = unix_net_exit,
2901 };
2902
2903 static int __init af_unix_init(void)
2904 {
2905         int rc = -1;
2906
2907         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2908
2909         rc = proto_register(&unix_proto, 1);
2910         if (rc != 0) {
2911                 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
2912                 goto out;
2913         }
2914
2915         sock_register(&unix_family_ops);
2916         register_pernet_subsys(&unix_net_ops);
2917 out:
2918         return rc;
2919 }
2920
2921 static void __exit af_unix_exit(void)
2922 {
2923         sock_unregister(PF_UNIX);
2924         proto_unregister(&unix_proto);
2925         unregister_pernet_subsys(&unix_net_ops);
2926 }
2927
2928 /* Earlier than device_initcall() so that other drivers invoking
2929    request_module() don't end up in a loop when modprobe tries
2930    to use a UNIX socket. But later than subsys_initcall() because
2931    we depend on stuff initialised there */
2932 fs_initcall(af_unix_init);
2933 module_exit(af_unix_exit);
2934
2935 MODULE_LICENSE("GPL");
2936 MODULE_ALIAS_NETPROTO(PF_UNIX);