af_unix: fix unix_dgram_poll() behavior for EPOLLOUT event
[linux-3.10.git] / net / unix / af_unix.c
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 #include <linux/module.h>
84 #include <linux/kernel.h>
85 #include <linux/signal.h>
86 #include <linux/sched.h>
87 #include <linux/errno.h>
88 #include <linux/string.h>
89 #include <linux/stat.h>
90 #include <linux/dcache.h>
91 #include <linux/namei.h>
92 #include <linux/socket.h>
93 #include <linux/un.h>
94 #include <linux/fcntl.h>
95 #include <linux/termios.h>
96 #include <linux/sockios.h>
97 #include <linux/net.h>
98 #include <linux/in.h>
99 #include <linux/fs.h>
100 #include <linux/slab.h>
101 #include <asm/uaccess.h>
102 #include <linux/skbuff.h>
103 #include <linux/netdevice.h>
104 #include <net/net_namespace.h>
105 #include <net/sock.h>
106 #include <net/tcp_states.h>
107 #include <net/af_unix.h>
108 #include <linux/proc_fs.h>
109 #include <linux/seq_file.h>
110 #include <net/scm.h>
111 #include <linux/init.h>
112 #include <linux/poll.h>
113 #include <linux/rtnetlink.h>
114 #include <linux/mount.h>
115 #include <net/checksum.h>
116 #include <linux/security.h>
117
118 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
119 static DEFINE_SPINLOCK(unix_table_lock);
120 static atomic_long_t unix_nr_socks;
121
122 #define unix_sockets_unbound    (&unix_socket_table[UNIX_HASH_SIZE])
123
124 #define UNIX_ABSTRACT(sk)       (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
125
126 #ifdef CONFIG_SECURITY_NETWORK
127 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
128 {
129         memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
130 }
131
132 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
133 {
134         scm->secid = *UNIXSID(skb);
135 }
136 #else
137 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
138 { }
139
140 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
141 { }
142 #endif /* CONFIG_SECURITY_NETWORK */
143
144 /*
145  *  SMP locking strategy:
146  *    hash table is protected with spinlock unix_table_lock
147  *    each socket state is protected by separate spin lock.
148  */
149
150 static inline unsigned unix_hash_fold(__wsum n)
151 {
152         unsigned hash = (__force unsigned)n;
153         hash ^= hash>>16;
154         hash ^= hash>>8;
155         return hash&(UNIX_HASH_SIZE-1);
156 }
157
158 #define unix_peer(sk) (unix_sk(sk)->peer)
159
160 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
161 {
162         return unix_peer(osk) == sk;
163 }
164
165 static inline int unix_may_send(struct sock *sk, struct sock *osk)
166 {
167         return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
168 }
169
170 static inline int unix_recvq_full(struct sock const *sk)
171 {
172         return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
173 }
174
175 static struct sock *unix_peer_get(struct sock *s)
176 {
177         struct sock *peer;
178
179         unix_state_lock(s);
180         peer = unix_peer(s);
181         if (peer)
182                 sock_hold(peer);
183         unix_state_unlock(s);
184         return peer;
185 }
186
187 static inline void unix_release_addr(struct unix_address *addr)
188 {
189         if (atomic_dec_and_test(&addr->refcnt))
190                 kfree(addr);
191 }
192
193 /*
194  *      Check unix socket name:
195  *              - should be not zero length.
196  *              - if started by not zero, should be NULL terminated (FS object)
197  *              - if started by zero, it is abstract name.
198  */
199
200 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
201 {
202         if (len <= sizeof(short) || len > sizeof(*sunaddr))
203                 return -EINVAL;
204         if (!sunaddr || sunaddr->sun_family != AF_UNIX)
205                 return -EINVAL;
206         if (sunaddr->sun_path[0]) {
207                 /*
208                  * This may look like an off by one error but it is a bit more
209                  * subtle. 108 is the longest valid AF_UNIX path for a binding.
210                  * sun_path[108] doesnt as such exist.  However in kernel space
211                  * we are guaranteed that it is a valid memory location in our
212                  * kernel address buffer.
213                  */
214                 ((char *)sunaddr)[len] = 0;
215                 len = strlen(sunaddr->sun_path)+1+sizeof(short);
216                 return len;
217         }
218
219         *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
220         return len;
221 }
222
223 static void __unix_remove_socket(struct sock *sk)
224 {
225         sk_del_node_init(sk);
226 }
227
228 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
229 {
230         WARN_ON(!sk_unhashed(sk));
231         sk_add_node(sk, list);
232 }
233
234 static inline void unix_remove_socket(struct sock *sk)
235 {
236         spin_lock(&unix_table_lock);
237         __unix_remove_socket(sk);
238         spin_unlock(&unix_table_lock);
239 }
240
241 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
242 {
243         spin_lock(&unix_table_lock);
244         __unix_insert_socket(list, sk);
245         spin_unlock(&unix_table_lock);
246 }
247
248 static struct sock *__unix_find_socket_byname(struct net *net,
249                                               struct sockaddr_un *sunname,
250                                               int len, int type, unsigned hash)
251 {
252         struct sock *s;
253         struct hlist_node *node;
254
255         sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
256                 struct unix_sock *u = unix_sk(s);
257
258                 if (!net_eq(sock_net(s), net))
259                         continue;
260
261                 if (u->addr->len == len &&
262                     !memcmp(u->addr->name, sunname, len))
263                         goto found;
264         }
265         s = NULL;
266 found:
267         return s;
268 }
269
270 static inline struct sock *unix_find_socket_byname(struct net *net,
271                                                    struct sockaddr_un *sunname,
272                                                    int len, int type,
273                                                    unsigned hash)
274 {
275         struct sock *s;
276
277         spin_lock(&unix_table_lock);
278         s = __unix_find_socket_byname(net, sunname, len, type, hash);
279         if (s)
280                 sock_hold(s);
281         spin_unlock(&unix_table_lock);
282         return s;
283 }
284
285 static struct sock *unix_find_socket_byinode(struct inode *i)
286 {
287         struct sock *s;
288         struct hlist_node *node;
289
290         spin_lock(&unix_table_lock);
291         sk_for_each(s, node,
292                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
293                 struct dentry *dentry = unix_sk(s)->dentry;
294
295                 if (dentry && dentry->d_inode == i) {
296                         sock_hold(s);
297                         goto found;
298                 }
299         }
300         s = NULL;
301 found:
302         spin_unlock(&unix_table_lock);
303         return s;
304 }
305
306 static inline int unix_writable(struct sock *sk)
307 {
308         return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
309 }
310
311 static void unix_write_space(struct sock *sk)
312 {
313         struct socket_wq *wq;
314
315         rcu_read_lock();
316         if (unix_writable(sk)) {
317                 wq = rcu_dereference(sk->sk_wq);
318                 if (wq_has_sleeper(wq))
319                         wake_up_interruptible_sync_poll(&wq->wait,
320                                 POLLOUT | POLLWRNORM | POLLWRBAND);
321                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
322         }
323         rcu_read_unlock();
324 }
325
326 /* When dgram socket disconnects (or changes its peer), we clear its receive
327  * queue of packets arrived from previous peer. First, it allows to do
328  * flow control based only on wmem_alloc; second, sk connected to peer
329  * may receive messages only from that peer. */
330 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
331 {
332         if (!skb_queue_empty(&sk->sk_receive_queue)) {
333                 skb_queue_purge(&sk->sk_receive_queue);
334                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
335
336                 /* If one link of bidirectional dgram pipe is disconnected,
337                  * we signal error. Messages are lost. Do not make this,
338                  * when peer was not connected to us.
339                  */
340                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
341                         other->sk_err = ECONNRESET;
342                         other->sk_error_report(other);
343                 }
344         }
345 }
346
347 static void unix_sock_destructor(struct sock *sk)
348 {
349         struct unix_sock *u = unix_sk(sk);
350
351         skb_queue_purge(&sk->sk_receive_queue);
352
353         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
354         WARN_ON(!sk_unhashed(sk));
355         WARN_ON(sk->sk_socket);
356         if (!sock_flag(sk, SOCK_DEAD)) {
357                 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
358                 return;
359         }
360
361         if (u->addr)
362                 unix_release_addr(u->addr);
363
364         atomic_long_dec(&unix_nr_socks);
365         local_bh_disable();
366         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
367         local_bh_enable();
368 #ifdef UNIX_REFCNT_DEBUG
369         printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
370                 atomic_long_read(&unix_nr_socks));
371 #endif
372 }
373
374 static int unix_release_sock(struct sock *sk, int embrion)
375 {
376         struct unix_sock *u = unix_sk(sk);
377         struct dentry *dentry;
378         struct vfsmount *mnt;
379         struct sock *skpair;
380         struct sk_buff *skb;
381         int state;
382
383         unix_remove_socket(sk);
384
385         /* Clear state */
386         unix_state_lock(sk);
387         sock_orphan(sk);
388         sk->sk_shutdown = SHUTDOWN_MASK;
389         dentry       = u->dentry;
390         u->dentry    = NULL;
391         mnt          = u->mnt;
392         u->mnt       = NULL;
393         state = sk->sk_state;
394         sk->sk_state = TCP_CLOSE;
395         unix_state_unlock(sk);
396
397         wake_up_interruptible_all(&u->peer_wait);
398
399         skpair = unix_peer(sk);
400
401         if (skpair != NULL) {
402                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
403                         unix_state_lock(skpair);
404                         /* No more writes */
405                         skpair->sk_shutdown = SHUTDOWN_MASK;
406                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
407                                 skpair->sk_err = ECONNRESET;
408                         unix_state_unlock(skpair);
409                         skpair->sk_state_change(skpair);
410                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
411                 }
412                 sock_put(skpair); /* It may now die */
413                 unix_peer(sk) = NULL;
414         }
415
416         /* Try to flush out this socket. Throw out buffers at least */
417
418         while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
419                 if (state == TCP_LISTEN)
420                         unix_release_sock(skb->sk, 1);
421                 /* passed fds are erased in the kfree_skb hook        */
422                 kfree_skb(skb);
423         }
424
425         if (dentry) {
426                 dput(dentry);
427                 mntput(mnt);
428         }
429
430         sock_put(sk);
431
432         /* ---- Socket is dead now and most probably destroyed ---- */
433
434         /*
435          * Fixme: BSD difference: In BSD all sockets connected to use get
436          *        ECONNRESET and we die on the spot. In Linux we behave
437          *        like files and pipes do and wait for the last
438          *        dereference.
439          *
440          * Can't we simply set sock->err?
441          *
442          *        What the above comment does talk about? --ANK(980817)
443          */
444
445         if (unix_tot_inflight)
446                 unix_gc();              /* Garbage collect fds */
447
448         return 0;
449 }
450
451 static void init_peercred(struct sock *sk)
452 {
453         put_pid(sk->sk_peer_pid);
454         if (sk->sk_peer_cred)
455                 put_cred(sk->sk_peer_cred);
456         sk->sk_peer_pid  = get_pid(task_tgid(current));
457         sk->sk_peer_cred = get_current_cred();
458 }
459
460 static void copy_peercred(struct sock *sk, struct sock *peersk)
461 {
462         put_pid(sk->sk_peer_pid);
463         if (sk->sk_peer_cred)
464                 put_cred(sk->sk_peer_cred);
465         sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
466         sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
467 }
468
469 static int unix_listen(struct socket *sock, int backlog)
470 {
471         int err;
472         struct sock *sk = sock->sk;
473         struct unix_sock *u = unix_sk(sk);
474         struct pid *old_pid = NULL;
475         const struct cred *old_cred = NULL;
476
477         err = -EOPNOTSUPP;
478         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
479                 goto out;       /* Only stream/seqpacket sockets accept */
480         err = -EINVAL;
481         if (!u->addr)
482                 goto out;       /* No listens on an unbound socket */
483         unix_state_lock(sk);
484         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
485                 goto out_unlock;
486         if (backlog > sk->sk_max_ack_backlog)
487                 wake_up_interruptible_all(&u->peer_wait);
488         sk->sk_max_ack_backlog  = backlog;
489         sk->sk_state            = TCP_LISTEN;
490         /* set credentials so connect can copy them */
491         init_peercred(sk);
492         err = 0;
493
494 out_unlock:
495         unix_state_unlock(sk);
496         put_pid(old_pid);
497         if (old_cred)
498                 put_cred(old_cred);
499 out:
500         return err;
501 }
502
503 static int unix_release(struct socket *);
504 static int unix_bind(struct socket *, struct sockaddr *, int);
505 static int unix_stream_connect(struct socket *, struct sockaddr *,
506                                int addr_len, int flags);
507 static int unix_socketpair(struct socket *, struct socket *);
508 static int unix_accept(struct socket *, struct socket *, int);
509 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
510 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
511 static unsigned int unix_dgram_poll(struct file *, struct socket *,
512                                     poll_table *);
513 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
514 static int unix_shutdown(struct socket *, int);
515 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
516                                struct msghdr *, size_t);
517 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
518                                struct msghdr *, size_t, int);
519 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
520                               struct msghdr *, size_t);
521 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
522                               struct msghdr *, size_t, int);
523 static int unix_dgram_connect(struct socket *, struct sockaddr *,
524                               int, int);
525 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
526                                   struct msghdr *, size_t);
527
528 static const struct proto_ops unix_stream_ops = {
529         .family =       PF_UNIX,
530         .owner =        THIS_MODULE,
531         .release =      unix_release,
532         .bind =         unix_bind,
533         .connect =      unix_stream_connect,
534         .socketpair =   unix_socketpair,
535         .accept =       unix_accept,
536         .getname =      unix_getname,
537         .poll =         unix_poll,
538         .ioctl =        unix_ioctl,
539         .listen =       unix_listen,
540         .shutdown =     unix_shutdown,
541         .setsockopt =   sock_no_setsockopt,
542         .getsockopt =   sock_no_getsockopt,
543         .sendmsg =      unix_stream_sendmsg,
544         .recvmsg =      unix_stream_recvmsg,
545         .mmap =         sock_no_mmap,
546         .sendpage =     sock_no_sendpage,
547 };
548
549 static const struct proto_ops unix_dgram_ops = {
550         .family =       PF_UNIX,
551         .owner =        THIS_MODULE,
552         .release =      unix_release,
553         .bind =         unix_bind,
554         .connect =      unix_dgram_connect,
555         .socketpair =   unix_socketpair,
556         .accept =       sock_no_accept,
557         .getname =      unix_getname,
558         .poll =         unix_dgram_poll,
559         .ioctl =        unix_ioctl,
560         .listen =       sock_no_listen,
561         .shutdown =     unix_shutdown,
562         .setsockopt =   sock_no_setsockopt,
563         .getsockopt =   sock_no_getsockopt,
564         .sendmsg =      unix_dgram_sendmsg,
565         .recvmsg =      unix_dgram_recvmsg,
566         .mmap =         sock_no_mmap,
567         .sendpage =     sock_no_sendpage,
568 };
569
570 static const struct proto_ops unix_seqpacket_ops = {
571         .family =       PF_UNIX,
572         .owner =        THIS_MODULE,
573         .release =      unix_release,
574         .bind =         unix_bind,
575         .connect =      unix_stream_connect,
576         .socketpair =   unix_socketpair,
577         .accept =       unix_accept,
578         .getname =      unix_getname,
579         .poll =         unix_dgram_poll,
580         .ioctl =        unix_ioctl,
581         .listen =       unix_listen,
582         .shutdown =     unix_shutdown,
583         .setsockopt =   sock_no_setsockopt,
584         .getsockopt =   sock_no_getsockopt,
585         .sendmsg =      unix_seqpacket_sendmsg,
586         .recvmsg =      unix_dgram_recvmsg,
587         .mmap =         sock_no_mmap,
588         .sendpage =     sock_no_sendpage,
589 };
590
591 static struct proto unix_proto = {
592         .name                   = "UNIX",
593         .owner                  = THIS_MODULE,
594         .obj_size               = sizeof(struct unix_sock),
595 };
596
597 /*
598  * AF_UNIX sockets do not interact with hardware, hence they
599  * dont trigger interrupts - so it's safe for them to have
600  * bh-unsafe locking for their sk_receive_queue.lock. Split off
601  * this special lock-class by reinitializing the spinlock key:
602  */
603 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
604
605 static struct sock *unix_create1(struct net *net, struct socket *sock)
606 {
607         struct sock *sk = NULL;
608         struct unix_sock *u;
609
610         atomic_long_inc(&unix_nr_socks);
611         if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
612                 goto out;
613
614         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
615         if (!sk)
616                 goto out;
617
618         sock_init_data(sock, sk);
619         lockdep_set_class(&sk->sk_receive_queue.lock,
620                                 &af_unix_sk_receive_queue_lock_key);
621
622         sk->sk_write_space      = unix_write_space;
623         sk->sk_max_ack_backlog  = net->unx.sysctl_max_dgram_qlen;
624         sk->sk_destruct         = unix_sock_destructor;
625         u         = unix_sk(sk);
626         u->dentry = NULL;
627         u->mnt    = NULL;
628         spin_lock_init(&u->lock);
629         atomic_long_set(&u->inflight, 0);
630         INIT_LIST_HEAD(&u->link);
631         mutex_init(&u->readlock); /* single task reading lock */
632         init_waitqueue_head(&u->peer_wait);
633         unix_insert_socket(unix_sockets_unbound, sk);
634 out:
635         if (sk == NULL)
636                 atomic_long_dec(&unix_nr_socks);
637         else {
638                 local_bh_disable();
639                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
640                 local_bh_enable();
641         }
642         return sk;
643 }
644
645 static int unix_create(struct net *net, struct socket *sock, int protocol,
646                        int kern)
647 {
648         if (protocol && protocol != PF_UNIX)
649                 return -EPROTONOSUPPORT;
650
651         sock->state = SS_UNCONNECTED;
652
653         switch (sock->type) {
654         case SOCK_STREAM:
655                 sock->ops = &unix_stream_ops;
656                 break;
657                 /*
658                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
659                  *      nothing uses it.
660                  */
661         case SOCK_RAW:
662                 sock->type = SOCK_DGRAM;
663         case SOCK_DGRAM:
664                 sock->ops = &unix_dgram_ops;
665                 break;
666         case SOCK_SEQPACKET:
667                 sock->ops = &unix_seqpacket_ops;
668                 break;
669         default:
670                 return -ESOCKTNOSUPPORT;
671         }
672
673         return unix_create1(net, sock) ? 0 : -ENOMEM;
674 }
675
676 static int unix_release(struct socket *sock)
677 {
678         struct sock *sk = sock->sk;
679
680         if (!sk)
681                 return 0;
682
683         sock->sk = NULL;
684
685         return unix_release_sock(sk, 0);
686 }
687
688 static int unix_autobind(struct socket *sock)
689 {
690         struct sock *sk = sock->sk;
691         struct net *net = sock_net(sk);
692         struct unix_sock *u = unix_sk(sk);
693         static u32 ordernum = 1;
694         struct unix_address *addr;
695         int err;
696         unsigned int retries = 0;
697
698         mutex_lock(&u->readlock);
699
700         err = 0;
701         if (u->addr)
702                 goto out;
703
704         err = -ENOMEM;
705         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
706         if (!addr)
707                 goto out;
708
709         addr->name->sun_family = AF_UNIX;
710         atomic_set(&addr->refcnt, 1);
711
712 retry:
713         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
714         addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
715
716         spin_lock(&unix_table_lock);
717         ordernum = (ordernum+1)&0xFFFFF;
718
719         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
720                                       addr->hash)) {
721                 spin_unlock(&unix_table_lock);
722                 /*
723                  * __unix_find_socket_byname() may take long time if many names
724                  * are already in use.
725                  */
726                 cond_resched();
727                 /* Give up if all names seems to be in use. */
728                 if (retries++ == 0xFFFFF) {
729                         err = -ENOSPC;
730                         kfree(addr);
731                         goto out;
732                 }
733                 goto retry;
734         }
735         addr->hash ^= sk->sk_type;
736
737         __unix_remove_socket(sk);
738         u->addr = addr;
739         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
740         spin_unlock(&unix_table_lock);
741         err = 0;
742
743 out:    mutex_unlock(&u->readlock);
744         return err;
745 }
746
747 static struct sock *unix_find_other(struct net *net,
748                                     struct sockaddr_un *sunname, int len,
749                                     int type, unsigned hash, int *error)
750 {
751         struct sock *u;
752         struct path path;
753         int err = 0;
754
755         if (sunname->sun_path[0]) {
756                 struct inode *inode;
757                 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
758                 if (err)
759                         goto fail;
760                 inode = path.dentry->d_inode;
761                 err = inode_permission(inode, MAY_WRITE);
762                 if (err)
763                         goto put_fail;
764
765                 err = -ECONNREFUSED;
766                 if (!S_ISSOCK(inode->i_mode))
767                         goto put_fail;
768                 u = unix_find_socket_byinode(inode);
769                 if (!u)
770                         goto put_fail;
771
772                 if (u->sk_type == type)
773                         touch_atime(path.mnt, path.dentry);
774
775                 path_put(&path);
776
777                 err = -EPROTOTYPE;
778                 if (u->sk_type != type) {
779                         sock_put(u);
780                         goto fail;
781                 }
782         } else {
783                 err = -ECONNREFUSED;
784                 u = unix_find_socket_byname(net, sunname, len, type, hash);
785                 if (u) {
786                         struct dentry *dentry;
787                         dentry = unix_sk(u)->dentry;
788                         if (dentry)
789                                 touch_atime(unix_sk(u)->mnt, dentry);
790                 } else
791                         goto fail;
792         }
793         return u;
794
795 put_fail:
796         path_put(&path);
797 fail:
798         *error = err;
799         return NULL;
800 }
801
802
803 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
804 {
805         struct sock *sk = sock->sk;
806         struct net *net = sock_net(sk);
807         struct unix_sock *u = unix_sk(sk);
808         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
809         struct dentry *dentry = NULL;
810         struct nameidata nd;
811         int err;
812         unsigned hash;
813         struct unix_address *addr;
814         struct hlist_head *list;
815
816         err = -EINVAL;
817         if (sunaddr->sun_family != AF_UNIX)
818                 goto out;
819
820         if (addr_len == sizeof(short)) {
821                 err = unix_autobind(sock);
822                 goto out;
823         }
824
825         err = unix_mkname(sunaddr, addr_len, &hash);
826         if (err < 0)
827                 goto out;
828         addr_len = err;
829
830         mutex_lock(&u->readlock);
831
832         err = -EINVAL;
833         if (u->addr)
834                 goto out_up;
835
836         err = -ENOMEM;
837         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
838         if (!addr)
839                 goto out_up;
840
841         memcpy(addr->name, sunaddr, addr_len);
842         addr->len = addr_len;
843         addr->hash = hash ^ sk->sk_type;
844         atomic_set(&addr->refcnt, 1);
845
846         if (sunaddr->sun_path[0]) {
847                 unsigned int mode;
848                 err = 0;
849                 /*
850                  * Get the parent directory, calculate the hash for last
851                  * component.
852                  */
853                 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
854                 if (err)
855                         goto out_mknod_parent;
856
857                 dentry = lookup_create(&nd, 0);
858                 err = PTR_ERR(dentry);
859                 if (IS_ERR(dentry))
860                         goto out_mknod_unlock;
861
862                 /*
863                  * All right, let's create it.
864                  */
865                 mode = S_IFSOCK |
866                        (SOCK_INODE(sock)->i_mode & ~current_umask());
867                 err = mnt_want_write(nd.path.mnt);
868                 if (err)
869                         goto out_mknod_dput;
870                 err = security_path_mknod(&nd.path, dentry, mode, 0);
871                 if (err)
872                         goto out_mknod_drop_write;
873                 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
874 out_mknod_drop_write:
875                 mnt_drop_write(nd.path.mnt);
876                 if (err)
877                         goto out_mknod_dput;
878                 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
879                 dput(nd.path.dentry);
880                 nd.path.dentry = dentry;
881
882                 addr->hash = UNIX_HASH_SIZE;
883         }
884
885         spin_lock(&unix_table_lock);
886
887         if (!sunaddr->sun_path[0]) {
888                 err = -EADDRINUSE;
889                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
890                                               sk->sk_type, hash)) {
891                         unix_release_addr(addr);
892                         goto out_unlock;
893                 }
894
895                 list = &unix_socket_table[addr->hash];
896         } else {
897                 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
898                 u->dentry = nd.path.dentry;
899                 u->mnt    = nd.path.mnt;
900         }
901
902         err = 0;
903         __unix_remove_socket(sk);
904         u->addr = addr;
905         __unix_insert_socket(list, sk);
906
907 out_unlock:
908         spin_unlock(&unix_table_lock);
909 out_up:
910         mutex_unlock(&u->readlock);
911 out:
912         return err;
913
914 out_mknod_dput:
915         dput(dentry);
916 out_mknod_unlock:
917         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
918         path_put(&nd.path);
919 out_mknod_parent:
920         if (err == -EEXIST)
921                 err = -EADDRINUSE;
922         unix_release_addr(addr);
923         goto out_up;
924 }
925
926 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
927 {
928         if (unlikely(sk1 == sk2) || !sk2) {
929                 unix_state_lock(sk1);
930                 return;
931         }
932         if (sk1 < sk2) {
933                 unix_state_lock(sk1);
934                 unix_state_lock_nested(sk2);
935         } else {
936                 unix_state_lock(sk2);
937                 unix_state_lock_nested(sk1);
938         }
939 }
940
941 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
942 {
943         if (unlikely(sk1 == sk2) || !sk2) {
944                 unix_state_unlock(sk1);
945                 return;
946         }
947         unix_state_unlock(sk1);
948         unix_state_unlock(sk2);
949 }
950
951 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
952                               int alen, int flags)
953 {
954         struct sock *sk = sock->sk;
955         struct net *net = sock_net(sk);
956         struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
957         struct sock *other;
958         unsigned hash;
959         int err;
960
961         if (addr->sa_family != AF_UNSPEC) {
962                 err = unix_mkname(sunaddr, alen, &hash);
963                 if (err < 0)
964                         goto out;
965                 alen = err;
966
967                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
968                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
969                         goto out;
970
971 restart:
972                 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
973                 if (!other)
974                         goto out;
975
976                 unix_state_double_lock(sk, other);
977
978                 /* Apparently VFS overslept socket death. Retry. */
979                 if (sock_flag(other, SOCK_DEAD)) {
980                         unix_state_double_unlock(sk, other);
981                         sock_put(other);
982                         goto restart;
983                 }
984
985                 err = -EPERM;
986                 if (!unix_may_send(sk, other))
987                         goto out_unlock;
988
989                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
990                 if (err)
991                         goto out_unlock;
992
993         } else {
994                 /*
995                  *      1003.1g breaking connected state with AF_UNSPEC
996                  */
997                 other = NULL;
998                 unix_state_double_lock(sk, other);
999         }
1000
1001         /*
1002          * If it was connected, reconnect.
1003          */
1004         if (unix_peer(sk)) {
1005                 struct sock *old_peer = unix_peer(sk);
1006                 unix_peer(sk) = other;
1007                 unix_state_double_unlock(sk, other);
1008
1009                 if (other != old_peer)
1010                         unix_dgram_disconnected(sk, old_peer);
1011                 sock_put(old_peer);
1012         } else {
1013                 unix_peer(sk) = other;
1014                 unix_state_double_unlock(sk, other);
1015         }
1016         return 0;
1017
1018 out_unlock:
1019         unix_state_double_unlock(sk, other);
1020         sock_put(other);
1021 out:
1022         return err;
1023 }
1024
1025 static long unix_wait_for_peer(struct sock *other, long timeo)
1026 {
1027         struct unix_sock *u = unix_sk(other);
1028         int sched;
1029         DEFINE_WAIT(wait);
1030
1031         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1032
1033         sched = !sock_flag(other, SOCK_DEAD) &&
1034                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1035                 unix_recvq_full(other);
1036
1037         unix_state_unlock(other);
1038
1039         if (sched)
1040                 timeo = schedule_timeout(timeo);
1041
1042         finish_wait(&u->peer_wait, &wait);
1043         return timeo;
1044 }
1045
1046 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1047                                int addr_len, int flags)
1048 {
1049         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1050         struct sock *sk = sock->sk;
1051         struct net *net = sock_net(sk);
1052         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1053         struct sock *newsk = NULL;
1054         struct sock *other = NULL;
1055         struct sk_buff *skb = NULL;
1056         unsigned hash;
1057         int st;
1058         int err;
1059         long timeo;
1060
1061         err = unix_mkname(sunaddr, addr_len, &hash);
1062         if (err < 0)
1063                 goto out;
1064         addr_len = err;
1065
1066         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1067             (err = unix_autobind(sock)) != 0)
1068                 goto out;
1069
1070         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1071
1072         /* First of all allocate resources.
1073            If we will make it after state is locked,
1074            we will have to recheck all again in any case.
1075          */
1076
1077         err = -ENOMEM;
1078
1079         /* create new sock for complete connection */
1080         newsk = unix_create1(sock_net(sk), NULL);
1081         if (newsk == NULL)
1082                 goto out;
1083
1084         /* Allocate skb for sending to listening sock */
1085         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1086         if (skb == NULL)
1087                 goto out;
1088
1089 restart:
1090         /*  Find listening sock. */
1091         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1092         if (!other)
1093                 goto out;
1094
1095         /* Latch state of peer */
1096         unix_state_lock(other);
1097
1098         /* Apparently VFS overslept socket death. Retry. */
1099         if (sock_flag(other, SOCK_DEAD)) {
1100                 unix_state_unlock(other);
1101                 sock_put(other);
1102                 goto restart;
1103         }
1104
1105         err = -ECONNREFUSED;
1106         if (other->sk_state != TCP_LISTEN)
1107                 goto out_unlock;
1108         if (other->sk_shutdown & RCV_SHUTDOWN)
1109                 goto out_unlock;
1110
1111         if (unix_recvq_full(other)) {
1112                 err = -EAGAIN;
1113                 if (!timeo)
1114                         goto out_unlock;
1115
1116                 timeo = unix_wait_for_peer(other, timeo);
1117
1118                 err = sock_intr_errno(timeo);
1119                 if (signal_pending(current))
1120                         goto out;
1121                 sock_put(other);
1122                 goto restart;
1123         }
1124
1125         /* Latch our state.
1126
1127            It is tricky place. We need to grab write lock and cannot
1128            drop lock on peer. It is dangerous because deadlock is
1129            possible. Connect to self case and simultaneous
1130            attempt to connect are eliminated by checking socket
1131            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1132            check this before attempt to grab lock.
1133
1134            Well, and we have to recheck the state after socket locked.
1135          */
1136         st = sk->sk_state;
1137
1138         switch (st) {
1139         case TCP_CLOSE:
1140                 /* This is ok... continue with connect */
1141                 break;
1142         case TCP_ESTABLISHED:
1143                 /* Socket is already connected */
1144                 err = -EISCONN;
1145                 goto out_unlock;
1146         default:
1147                 err = -EINVAL;
1148                 goto out_unlock;
1149         }
1150
1151         unix_state_lock_nested(sk);
1152
1153         if (sk->sk_state != st) {
1154                 unix_state_unlock(sk);
1155                 unix_state_unlock(other);
1156                 sock_put(other);
1157                 goto restart;
1158         }
1159
1160         err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1161         if (err) {
1162                 unix_state_unlock(sk);
1163                 goto out_unlock;
1164         }
1165
1166         /* The way is open! Fastly set all the necessary fields... */
1167
1168         sock_hold(sk);
1169         unix_peer(newsk)        = sk;
1170         newsk->sk_state         = TCP_ESTABLISHED;
1171         newsk->sk_type          = sk->sk_type;
1172         init_peercred(newsk);
1173         newu = unix_sk(newsk);
1174         newsk->sk_wq            = &newu->peer_wq;
1175         otheru = unix_sk(other);
1176
1177         /* copy address information from listening to new sock*/
1178         if (otheru->addr) {
1179                 atomic_inc(&otheru->addr->refcnt);
1180                 newu->addr = otheru->addr;
1181         }
1182         if (otheru->dentry) {
1183                 newu->dentry    = dget(otheru->dentry);
1184                 newu->mnt       = mntget(otheru->mnt);
1185         }
1186
1187         /* Set credentials */
1188         copy_peercred(sk, other);
1189
1190         sock->state     = SS_CONNECTED;
1191         sk->sk_state    = TCP_ESTABLISHED;
1192         sock_hold(newsk);
1193
1194         smp_mb__after_atomic_inc();     /* sock_hold() does an atomic_inc() */
1195         unix_peer(sk)   = newsk;
1196
1197         unix_state_unlock(sk);
1198
1199         /* take ten and and send info to listening sock */
1200         spin_lock(&other->sk_receive_queue.lock);
1201         __skb_queue_tail(&other->sk_receive_queue, skb);
1202         spin_unlock(&other->sk_receive_queue.lock);
1203         unix_state_unlock(other);
1204         other->sk_data_ready(other, 0);
1205         sock_put(other);
1206         return 0;
1207
1208 out_unlock:
1209         if (other)
1210                 unix_state_unlock(other);
1211
1212 out:
1213         kfree_skb(skb);
1214         if (newsk)
1215                 unix_release_sock(newsk, 0);
1216         if (other)
1217                 sock_put(other);
1218         return err;
1219 }
1220
1221 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1222 {
1223         struct sock *ska = socka->sk, *skb = sockb->sk;
1224
1225         /* Join our sockets back to back */
1226         sock_hold(ska);
1227         sock_hold(skb);
1228         unix_peer(ska) = skb;
1229         unix_peer(skb) = ska;
1230         init_peercred(ska);
1231         init_peercred(skb);
1232
1233         if (ska->sk_type != SOCK_DGRAM) {
1234                 ska->sk_state = TCP_ESTABLISHED;
1235                 skb->sk_state = TCP_ESTABLISHED;
1236                 socka->state  = SS_CONNECTED;
1237                 sockb->state  = SS_CONNECTED;
1238         }
1239         return 0;
1240 }
1241
1242 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1243 {
1244         struct sock *sk = sock->sk;
1245         struct sock *tsk;
1246         struct sk_buff *skb;
1247         int err;
1248
1249         err = -EOPNOTSUPP;
1250         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1251                 goto out;
1252
1253         err = -EINVAL;
1254         if (sk->sk_state != TCP_LISTEN)
1255                 goto out;
1256
1257         /* If socket state is TCP_LISTEN it cannot change (for now...),
1258          * so that no locks are necessary.
1259          */
1260
1261         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1262         if (!skb) {
1263                 /* This means receive shutdown. */
1264                 if (err == 0)
1265                         err = -EINVAL;
1266                 goto out;
1267         }
1268
1269         tsk = skb->sk;
1270         skb_free_datagram(sk, skb);
1271         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1272
1273         /* attach accepted sock to socket */
1274         unix_state_lock(tsk);
1275         newsock->state = SS_CONNECTED;
1276         sock_graft(tsk, newsock);
1277         unix_state_unlock(tsk);
1278         return 0;
1279
1280 out:
1281         return err;
1282 }
1283
1284
1285 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1286 {
1287         struct sock *sk = sock->sk;
1288         struct unix_sock *u;
1289         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1290         int err = 0;
1291
1292         if (peer) {
1293                 sk = unix_peer_get(sk);
1294
1295                 err = -ENOTCONN;
1296                 if (!sk)
1297                         goto out;
1298                 err = 0;
1299         } else {
1300                 sock_hold(sk);
1301         }
1302
1303         u = unix_sk(sk);
1304         unix_state_lock(sk);
1305         if (!u->addr) {
1306                 sunaddr->sun_family = AF_UNIX;
1307                 sunaddr->sun_path[0] = 0;
1308                 *uaddr_len = sizeof(short);
1309         } else {
1310                 struct unix_address *addr = u->addr;
1311
1312                 *uaddr_len = addr->len;
1313                 memcpy(sunaddr, addr->name, *uaddr_len);
1314         }
1315         unix_state_unlock(sk);
1316         sock_put(sk);
1317 out:
1318         return err;
1319 }
1320
1321 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1322 {
1323         int i;
1324
1325         scm->fp = UNIXCB(skb).fp;
1326         UNIXCB(skb).fp = NULL;
1327
1328         for (i = scm->fp->count-1; i >= 0; i--)
1329                 unix_notinflight(scm->fp->fp[i]);
1330 }
1331
1332 static void unix_destruct_scm(struct sk_buff *skb)
1333 {
1334         struct scm_cookie scm;
1335         memset(&scm, 0, sizeof(scm));
1336         scm.pid  = UNIXCB(skb).pid;
1337         scm.cred = UNIXCB(skb).cred;
1338         if (UNIXCB(skb).fp)
1339                 unix_detach_fds(&scm, skb);
1340
1341         /* Alas, it calls VFS */
1342         /* So fscking what? fput() had been SMP-safe since the last Summer */
1343         scm_destroy(&scm);
1344         sock_wfree(skb);
1345 }
1346
1347 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1348 {
1349         int i;
1350
1351         /*
1352          * Need to duplicate file references for the sake of garbage
1353          * collection.  Otherwise a socket in the fps might become a
1354          * candidate for GC while the skb is not yet queued.
1355          */
1356         UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1357         if (!UNIXCB(skb).fp)
1358                 return -ENOMEM;
1359
1360         for (i = scm->fp->count-1; i >= 0; i--)
1361                 unix_inflight(scm->fp->fp[i]);
1362         return 0;
1363 }
1364
1365 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1366 {
1367         int err = 0;
1368         UNIXCB(skb).pid  = get_pid(scm->pid);
1369         UNIXCB(skb).cred = get_cred(scm->cred);
1370         UNIXCB(skb).fp = NULL;
1371         if (scm->fp && send_fds)
1372                 err = unix_attach_fds(scm, skb);
1373
1374         skb->destructor = unix_destruct_scm;
1375         return err;
1376 }
1377
1378 /*
1379  *      Send AF_UNIX data.
1380  */
1381
1382 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1383                               struct msghdr *msg, size_t len)
1384 {
1385         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1386         struct sock *sk = sock->sk;
1387         struct net *net = sock_net(sk);
1388         struct unix_sock *u = unix_sk(sk);
1389         struct sockaddr_un *sunaddr = msg->msg_name;
1390         struct sock *other = NULL;
1391         int namelen = 0; /* fake GCC */
1392         int err;
1393         unsigned hash;
1394         struct sk_buff *skb;
1395         long timeo;
1396         struct scm_cookie tmp_scm;
1397
1398         if (NULL == siocb->scm)
1399                 siocb->scm = &tmp_scm;
1400         wait_for_unix_gc();
1401         err = scm_send(sock, msg, siocb->scm);
1402         if (err < 0)
1403                 return err;
1404
1405         err = -EOPNOTSUPP;
1406         if (msg->msg_flags&MSG_OOB)
1407                 goto out;
1408
1409         if (msg->msg_namelen) {
1410                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1411                 if (err < 0)
1412                         goto out;
1413                 namelen = err;
1414         } else {
1415                 sunaddr = NULL;
1416                 err = -ENOTCONN;
1417                 other = unix_peer_get(sk);
1418                 if (!other)
1419                         goto out;
1420         }
1421
1422         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1423             && (err = unix_autobind(sock)) != 0)
1424                 goto out;
1425
1426         err = -EMSGSIZE;
1427         if (len > sk->sk_sndbuf - 32)
1428                 goto out;
1429
1430         skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1431         if (skb == NULL)
1432                 goto out;
1433
1434         err = unix_scm_to_skb(siocb->scm, skb, true);
1435         if (err)
1436                 goto out_free;
1437         unix_get_secdata(siocb->scm, skb);
1438
1439         skb_reset_transport_header(skb);
1440         err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1441         if (err)
1442                 goto out_free;
1443
1444         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1445
1446 restart:
1447         if (!other) {
1448                 err = -ECONNRESET;
1449                 if (sunaddr == NULL)
1450                         goto out_free;
1451
1452                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1453                                         hash, &err);
1454                 if (other == NULL)
1455                         goto out_free;
1456         }
1457
1458         unix_state_lock(other);
1459         err = -EPERM;
1460         if (!unix_may_send(sk, other))
1461                 goto out_unlock;
1462
1463         if (sock_flag(other, SOCK_DEAD)) {
1464                 /*
1465                  *      Check with 1003.1g - what should
1466                  *      datagram error
1467                  */
1468                 unix_state_unlock(other);
1469                 sock_put(other);
1470
1471                 err = 0;
1472                 unix_state_lock(sk);
1473                 if (unix_peer(sk) == other) {
1474                         unix_peer(sk) = NULL;
1475                         unix_state_unlock(sk);
1476
1477                         unix_dgram_disconnected(sk, other);
1478                         sock_put(other);
1479                         err = -ECONNREFUSED;
1480                 } else {
1481                         unix_state_unlock(sk);
1482                 }
1483
1484                 other = NULL;
1485                 if (err)
1486                         goto out_free;
1487                 goto restart;
1488         }
1489
1490         err = -EPIPE;
1491         if (other->sk_shutdown & RCV_SHUTDOWN)
1492                 goto out_unlock;
1493
1494         if (sk->sk_type != SOCK_SEQPACKET) {
1495                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1496                 if (err)
1497                         goto out_unlock;
1498         }
1499
1500         if (unix_peer(other) != sk && unix_recvq_full(other)) {
1501                 if (!timeo) {
1502                         err = -EAGAIN;
1503                         goto out_unlock;
1504                 }
1505
1506                 timeo = unix_wait_for_peer(other, timeo);
1507
1508                 err = sock_intr_errno(timeo);
1509                 if (signal_pending(current))
1510                         goto out_free;
1511
1512                 goto restart;
1513         }
1514
1515         if (sock_flag(other, SOCK_RCVTSTAMP))
1516                 __net_timestamp(skb);
1517         skb_queue_tail(&other->sk_receive_queue, skb);
1518         unix_state_unlock(other);
1519         other->sk_data_ready(other, len);
1520         sock_put(other);
1521         scm_destroy(siocb->scm);
1522         return len;
1523
1524 out_unlock:
1525         unix_state_unlock(other);
1526 out_free:
1527         kfree_skb(skb);
1528 out:
1529         if (other)
1530                 sock_put(other);
1531         scm_destroy(siocb->scm);
1532         return err;
1533 }
1534
1535
1536 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1537                                struct msghdr *msg, size_t len)
1538 {
1539         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1540         struct sock *sk = sock->sk;
1541         struct sock *other = NULL;
1542         struct sockaddr_un *sunaddr = msg->msg_name;
1543         int err, size;
1544         struct sk_buff *skb;
1545         int sent = 0;
1546         struct scm_cookie tmp_scm;
1547         bool fds_sent = false;
1548
1549         if (NULL == siocb->scm)
1550                 siocb->scm = &tmp_scm;
1551         wait_for_unix_gc();
1552         err = scm_send(sock, msg, siocb->scm);
1553         if (err < 0)
1554                 return err;
1555
1556         err = -EOPNOTSUPP;
1557         if (msg->msg_flags&MSG_OOB)
1558                 goto out_err;
1559
1560         if (msg->msg_namelen) {
1561                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1562                 goto out_err;
1563         } else {
1564                 sunaddr = NULL;
1565                 err = -ENOTCONN;
1566                 other = unix_peer(sk);
1567                 if (!other)
1568                         goto out_err;
1569         }
1570
1571         if (sk->sk_shutdown & SEND_SHUTDOWN)
1572                 goto pipe_err;
1573
1574         while (sent < len) {
1575                 /*
1576                  *      Optimisation for the fact that under 0.01% of X
1577                  *      messages typically need breaking up.
1578                  */
1579
1580                 size = len-sent;
1581
1582                 /* Keep two messages in the pipe so it schedules better */
1583                 if (size > ((sk->sk_sndbuf >> 1) - 64))
1584                         size = (sk->sk_sndbuf >> 1) - 64;
1585
1586                 if (size > SKB_MAX_ALLOC)
1587                         size = SKB_MAX_ALLOC;
1588
1589                 /*
1590                  *      Grab a buffer
1591                  */
1592
1593                 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1594                                           &err);
1595
1596                 if (skb == NULL)
1597                         goto out_err;
1598
1599                 /*
1600                  *      If you pass two values to the sock_alloc_send_skb
1601                  *      it tries to grab the large buffer with GFP_NOFS
1602                  *      (which can fail easily), and if it fails grab the
1603                  *      fallback size buffer which is under a page and will
1604                  *      succeed. [Alan]
1605                  */
1606                 size = min_t(int, size, skb_tailroom(skb));
1607
1608
1609                 /* Only send the fds in the first buffer */
1610                 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1611                 if (err) {
1612                         kfree_skb(skb);
1613                         goto out_err;
1614                 }
1615                 fds_sent = true;
1616
1617                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1618                 if (err) {
1619                         kfree_skb(skb);
1620                         goto out_err;
1621                 }
1622
1623                 unix_state_lock(other);
1624
1625                 if (sock_flag(other, SOCK_DEAD) ||
1626                     (other->sk_shutdown & RCV_SHUTDOWN))
1627                         goto pipe_err_free;
1628
1629                 skb_queue_tail(&other->sk_receive_queue, skb);
1630                 unix_state_unlock(other);
1631                 other->sk_data_ready(other, size);
1632                 sent += size;
1633         }
1634
1635         scm_destroy(siocb->scm);
1636         siocb->scm = NULL;
1637
1638         return sent;
1639
1640 pipe_err_free:
1641         unix_state_unlock(other);
1642         kfree_skb(skb);
1643 pipe_err:
1644         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1645                 send_sig(SIGPIPE, current, 0);
1646         err = -EPIPE;
1647 out_err:
1648         scm_destroy(siocb->scm);
1649         siocb->scm = NULL;
1650         return sent ? : err;
1651 }
1652
1653 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1654                                   struct msghdr *msg, size_t len)
1655 {
1656         int err;
1657         struct sock *sk = sock->sk;
1658
1659         err = sock_error(sk);
1660         if (err)
1661                 return err;
1662
1663         if (sk->sk_state != TCP_ESTABLISHED)
1664                 return -ENOTCONN;
1665
1666         if (msg->msg_namelen)
1667                 msg->msg_namelen = 0;
1668
1669         return unix_dgram_sendmsg(kiocb, sock, msg, len);
1670 }
1671
1672 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1673 {
1674         struct unix_sock *u = unix_sk(sk);
1675
1676         msg->msg_namelen = 0;
1677         if (u->addr) {
1678                 msg->msg_namelen = u->addr->len;
1679                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1680         }
1681 }
1682
1683 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1684                               struct msghdr *msg, size_t size,
1685                               int flags)
1686 {
1687         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1688         struct scm_cookie tmp_scm;
1689         struct sock *sk = sock->sk;
1690         struct unix_sock *u = unix_sk(sk);
1691         int noblock = flags & MSG_DONTWAIT;
1692         struct sk_buff *skb;
1693         int err;
1694
1695         err = -EOPNOTSUPP;
1696         if (flags&MSG_OOB)
1697                 goto out;
1698
1699         msg->msg_namelen = 0;
1700
1701         mutex_lock(&u->readlock);
1702
1703         skb = skb_recv_datagram(sk, flags, noblock, &err);
1704         if (!skb) {
1705                 unix_state_lock(sk);
1706                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1707                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1708                     (sk->sk_shutdown & RCV_SHUTDOWN))
1709                         err = 0;
1710                 unix_state_unlock(sk);
1711                 goto out_unlock;
1712         }
1713
1714         wake_up_interruptible_sync_poll(&u->peer_wait,
1715                                         POLLOUT | POLLWRNORM | POLLWRBAND);
1716
1717         if (msg->msg_name)
1718                 unix_copy_addr(msg, skb->sk);
1719
1720         if (size > skb->len)
1721                 size = skb->len;
1722         else if (size < skb->len)
1723                 msg->msg_flags |= MSG_TRUNC;
1724
1725         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1726         if (err)
1727                 goto out_free;
1728
1729         if (sock_flag(sk, SOCK_RCVTSTAMP))
1730                 __sock_recv_timestamp(msg, sk, skb);
1731
1732         if (!siocb->scm) {
1733                 siocb->scm = &tmp_scm;
1734                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1735         }
1736         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1737         unix_set_secdata(siocb->scm, skb);
1738
1739         if (!(flags & MSG_PEEK)) {
1740                 if (UNIXCB(skb).fp)
1741                         unix_detach_fds(siocb->scm, skb);
1742         } else {
1743                 /* It is questionable: on PEEK we could:
1744                    - do not return fds - good, but too simple 8)
1745                    - return fds, and do not return them on read (old strategy,
1746                      apparently wrong)
1747                    - clone fds (I chose it for now, it is the most universal
1748                      solution)
1749
1750                    POSIX 1003.1g does not actually define this clearly
1751                    at all. POSIX 1003.1g doesn't define a lot of things
1752                    clearly however!
1753
1754                 */
1755                 if (UNIXCB(skb).fp)
1756                         siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1757         }
1758         err = size;
1759
1760         scm_recv(sock, msg, siocb->scm, flags);
1761
1762 out_free:
1763         skb_free_datagram(sk, skb);
1764 out_unlock:
1765         mutex_unlock(&u->readlock);
1766 out:
1767         return err;
1768 }
1769
1770 /*
1771  *      Sleep until data has arrive. But check for races..
1772  */
1773
1774 static long unix_stream_data_wait(struct sock *sk, long timeo)
1775 {
1776         DEFINE_WAIT(wait);
1777
1778         unix_state_lock(sk);
1779
1780         for (;;) {
1781                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1782
1783                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1784                     sk->sk_err ||
1785                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
1786                     signal_pending(current) ||
1787                     !timeo)
1788                         break;
1789
1790                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1791                 unix_state_unlock(sk);
1792                 timeo = schedule_timeout(timeo);
1793                 unix_state_lock(sk);
1794                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1795         }
1796
1797         finish_wait(sk_sleep(sk), &wait);
1798         unix_state_unlock(sk);
1799         return timeo;
1800 }
1801
1802
1803
1804 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1805                                struct msghdr *msg, size_t size,
1806                                int flags)
1807 {
1808         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1809         struct scm_cookie tmp_scm;
1810         struct sock *sk = sock->sk;
1811         struct unix_sock *u = unix_sk(sk);
1812         struct sockaddr_un *sunaddr = msg->msg_name;
1813         int copied = 0;
1814         int check_creds = 0;
1815         int target;
1816         int err = 0;
1817         long timeo;
1818
1819         err = -EINVAL;
1820         if (sk->sk_state != TCP_ESTABLISHED)
1821                 goto out;
1822
1823         err = -EOPNOTSUPP;
1824         if (flags&MSG_OOB)
1825                 goto out;
1826
1827         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1828         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1829
1830         msg->msg_namelen = 0;
1831
1832         /* Lock the socket to prevent queue disordering
1833          * while sleeps in memcpy_tomsg
1834          */
1835
1836         if (!siocb->scm) {
1837                 siocb->scm = &tmp_scm;
1838                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1839         }
1840
1841         mutex_lock(&u->readlock);
1842
1843         do {
1844                 int chunk;
1845                 struct sk_buff *skb;
1846
1847                 unix_state_lock(sk);
1848                 skb = skb_dequeue(&sk->sk_receive_queue);
1849                 if (skb == NULL) {
1850                         if (copied >= target)
1851                                 goto unlock;
1852
1853                         /*
1854                          *      POSIX 1003.1g mandates this order.
1855                          */
1856
1857                         err = sock_error(sk);
1858                         if (err)
1859                                 goto unlock;
1860                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1861                                 goto unlock;
1862
1863                         unix_state_unlock(sk);
1864                         err = -EAGAIN;
1865                         if (!timeo)
1866                                 break;
1867                         mutex_unlock(&u->readlock);
1868
1869                         timeo = unix_stream_data_wait(sk, timeo);
1870
1871                         if (signal_pending(current)) {
1872                                 err = sock_intr_errno(timeo);
1873                                 goto out;
1874                         }
1875                         mutex_lock(&u->readlock);
1876                         continue;
1877  unlock:
1878                         unix_state_unlock(sk);
1879                         break;
1880                 }
1881                 unix_state_unlock(sk);
1882
1883                 if (check_creds) {
1884                         /* Never glue messages from different writers */
1885                         if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1886                             (UNIXCB(skb).cred != siocb->scm->cred)) {
1887                                 skb_queue_head(&sk->sk_receive_queue, skb);
1888                                 break;
1889                         }
1890                 } else {
1891                         /* Copy credentials */
1892                         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1893                         check_creds = 1;
1894                 }
1895
1896                 /* Copy address just once */
1897                 if (sunaddr) {
1898                         unix_copy_addr(msg, skb->sk);
1899                         sunaddr = NULL;
1900                 }
1901
1902                 chunk = min_t(unsigned int, skb->len, size);
1903                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1904                         skb_queue_head(&sk->sk_receive_queue, skb);
1905                         if (copied == 0)
1906                                 copied = -EFAULT;
1907                         break;
1908                 }
1909                 copied += chunk;
1910                 size -= chunk;
1911
1912                 /* Mark read part of skb as used */
1913                 if (!(flags & MSG_PEEK)) {
1914                         skb_pull(skb, chunk);
1915
1916                         if (UNIXCB(skb).fp)
1917                                 unix_detach_fds(siocb->scm, skb);
1918
1919                         /* put the skb back if we didn't use it up.. */
1920                         if (skb->len) {
1921                                 skb_queue_head(&sk->sk_receive_queue, skb);
1922                                 break;
1923                         }
1924
1925                         consume_skb(skb);
1926
1927                         if (siocb->scm->fp)
1928                                 break;
1929                 } else {
1930                         /* It is questionable, see note in unix_dgram_recvmsg.
1931                          */
1932                         if (UNIXCB(skb).fp)
1933                                 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1934
1935                         /* put message back and return */
1936                         skb_queue_head(&sk->sk_receive_queue, skb);
1937                         break;
1938                 }
1939         } while (size);
1940
1941         mutex_unlock(&u->readlock);
1942         scm_recv(sock, msg, siocb->scm, flags);
1943 out:
1944         return copied ? : err;
1945 }
1946
1947 static int unix_shutdown(struct socket *sock, int mode)
1948 {
1949         struct sock *sk = sock->sk;
1950         struct sock *other;
1951
1952         mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1953
1954         if (mode) {
1955                 unix_state_lock(sk);
1956                 sk->sk_shutdown |= mode;
1957                 other = unix_peer(sk);
1958                 if (other)
1959                         sock_hold(other);
1960                 unix_state_unlock(sk);
1961                 sk->sk_state_change(sk);
1962
1963                 if (other &&
1964                         (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1965
1966                         int peer_mode = 0;
1967
1968                         if (mode&RCV_SHUTDOWN)
1969                                 peer_mode |= SEND_SHUTDOWN;
1970                         if (mode&SEND_SHUTDOWN)
1971                                 peer_mode |= RCV_SHUTDOWN;
1972                         unix_state_lock(other);
1973                         other->sk_shutdown |= peer_mode;
1974                         unix_state_unlock(other);
1975                         other->sk_state_change(other);
1976                         if (peer_mode == SHUTDOWN_MASK)
1977                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1978                         else if (peer_mode & RCV_SHUTDOWN)
1979                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
1980                 }
1981                 if (other)
1982                         sock_put(other);
1983         }
1984         return 0;
1985 }
1986
1987 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1988 {
1989         struct sock *sk = sock->sk;
1990         long amount = 0;
1991         int err;
1992
1993         switch (cmd) {
1994         case SIOCOUTQ:
1995                 amount = sk_wmem_alloc_get(sk);
1996                 err = put_user(amount, (int __user *)arg);
1997                 break;
1998         case SIOCINQ:
1999                 {
2000                         struct sk_buff *skb;
2001
2002                         if (sk->sk_state == TCP_LISTEN) {
2003                                 err = -EINVAL;
2004                                 break;
2005                         }
2006
2007                         spin_lock(&sk->sk_receive_queue.lock);
2008                         if (sk->sk_type == SOCK_STREAM ||
2009                             sk->sk_type == SOCK_SEQPACKET) {
2010                                 skb_queue_walk(&sk->sk_receive_queue, skb)
2011                                         amount += skb->len;
2012                         } else {
2013                                 skb = skb_peek(&sk->sk_receive_queue);
2014                                 if (skb)
2015                                         amount = skb->len;
2016                         }
2017                         spin_unlock(&sk->sk_receive_queue.lock);
2018                         err = put_user(amount, (int __user *)arg);
2019                         break;
2020                 }
2021
2022         default:
2023                 err = -ENOIOCTLCMD;
2024                 break;
2025         }
2026         return err;
2027 }
2028
2029 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2030 {
2031         struct sock *sk = sock->sk;
2032         unsigned int mask;
2033
2034         sock_poll_wait(file, sk_sleep(sk), wait);
2035         mask = 0;
2036
2037         /* exceptional events? */
2038         if (sk->sk_err)
2039                 mask |= POLLERR;
2040         if (sk->sk_shutdown == SHUTDOWN_MASK)
2041                 mask |= POLLHUP;
2042         if (sk->sk_shutdown & RCV_SHUTDOWN)
2043                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2044
2045         /* readable? */
2046         if (!skb_queue_empty(&sk->sk_receive_queue))
2047                 mask |= POLLIN | POLLRDNORM;
2048
2049         /* Connection-based need to check for termination and startup */
2050         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2051             sk->sk_state == TCP_CLOSE)
2052                 mask |= POLLHUP;
2053
2054         /*
2055          * we set writable also when the other side has shut down the
2056          * connection. This prevents stuck sockets.
2057          */
2058         if (unix_writable(sk))
2059                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2060
2061         return mask;
2062 }
2063
2064 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2065                                     poll_table *wait)
2066 {
2067         struct sock *sk = sock->sk, *other;
2068         unsigned int mask, writable;
2069
2070         sock_poll_wait(file, sk_sleep(sk), wait);
2071         mask = 0;
2072
2073         /* exceptional events? */
2074         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2075                 mask |= POLLERR;
2076         if (sk->sk_shutdown & RCV_SHUTDOWN)
2077                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2078         if (sk->sk_shutdown == SHUTDOWN_MASK)
2079                 mask |= POLLHUP;
2080
2081         /* readable? */
2082         if (!skb_queue_empty(&sk->sk_receive_queue))
2083                 mask |= POLLIN | POLLRDNORM;
2084
2085         /* Connection-based need to check for termination and startup */
2086         if (sk->sk_type == SOCK_SEQPACKET) {
2087                 if (sk->sk_state == TCP_CLOSE)
2088                         mask |= POLLHUP;
2089                 /* connection hasn't started yet? */
2090                 if (sk->sk_state == TCP_SYN_SENT)
2091                         return mask;
2092         }
2093
2094         writable = unix_writable(sk);
2095         other = unix_peer_get(sk);
2096         if (other) {
2097                 if (unix_peer(other) != sk) {
2098                         sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2099                         if (unix_recvq_full(other))
2100                                 writable = 0;
2101                 }
2102                 sock_put(other);
2103         }
2104
2105         if (writable)
2106                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2107         else
2108                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2109
2110         return mask;
2111 }
2112
2113 #ifdef CONFIG_PROC_FS
2114 static struct sock *first_unix_socket(int *i)
2115 {
2116         for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2117                 if (!hlist_empty(&unix_socket_table[*i]))
2118                         return __sk_head(&unix_socket_table[*i]);
2119         }
2120         return NULL;
2121 }
2122
2123 static struct sock *next_unix_socket(int *i, struct sock *s)
2124 {
2125         struct sock *next = sk_next(s);
2126         /* More in this chain? */
2127         if (next)
2128                 return next;
2129         /* Look for next non-empty chain. */
2130         for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2131                 if (!hlist_empty(&unix_socket_table[*i]))
2132                         return __sk_head(&unix_socket_table[*i]);
2133         }
2134         return NULL;
2135 }
2136
2137 struct unix_iter_state {
2138         struct seq_net_private p;
2139         int i;
2140 };
2141
2142 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2143 {
2144         struct unix_iter_state *iter = seq->private;
2145         loff_t off = 0;
2146         struct sock *s;
2147
2148         for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2149                 if (sock_net(s) != seq_file_net(seq))
2150                         continue;
2151                 if (off == pos)
2152                         return s;
2153                 ++off;
2154         }
2155         return NULL;
2156 }
2157
2158 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2159         __acquires(unix_table_lock)
2160 {
2161         spin_lock(&unix_table_lock);
2162         return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2163 }
2164
2165 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2166 {
2167         struct unix_iter_state *iter = seq->private;
2168         struct sock *sk = v;
2169         ++*pos;
2170
2171         if (v == SEQ_START_TOKEN)
2172                 sk = first_unix_socket(&iter->i);
2173         else
2174                 sk = next_unix_socket(&iter->i, sk);
2175         while (sk && (sock_net(sk) != seq_file_net(seq)))
2176                 sk = next_unix_socket(&iter->i, sk);
2177         return sk;
2178 }
2179
2180 static void unix_seq_stop(struct seq_file *seq, void *v)
2181         __releases(unix_table_lock)
2182 {
2183         spin_unlock(&unix_table_lock);
2184 }
2185
2186 static int unix_seq_show(struct seq_file *seq, void *v)
2187 {
2188
2189         if (v == SEQ_START_TOKEN)
2190                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2191                          "Inode Path\n");
2192         else {
2193                 struct sock *s = v;
2194                 struct unix_sock *u = unix_sk(s);
2195                 unix_state_lock(s);
2196
2197                 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2198                         s,
2199                         atomic_read(&s->sk_refcnt),
2200                         0,
2201                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2202                         s->sk_type,
2203                         s->sk_socket ?
2204                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2205                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2206                         sock_i_ino(s));
2207
2208                 if (u->addr) {
2209                         int i, len;
2210                         seq_putc(seq, ' ');
2211
2212                         i = 0;
2213                         len = u->addr->len - sizeof(short);
2214                         if (!UNIX_ABSTRACT(s))
2215                                 len--;
2216                         else {
2217                                 seq_putc(seq, '@');
2218                                 i++;
2219                         }
2220                         for ( ; i < len; i++)
2221                                 seq_putc(seq, u->addr->name->sun_path[i]);
2222                 }
2223                 unix_state_unlock(s);
2224                 seq_putc(seq, '\n');
2225         }
2226
2227         return 0;
2228 }
2229
2230 static const struct seq_operations unix_seq_ops = {
2231         .start  = unix_seq_start,
2232         .next   = unix_seq_next,
2233         .stop   = unix_seq_stop,
2234         .show   = unix_seq_show,
2235 };
2236
2237 static int unix_seq_open(struct inode *inode, struct file *file)
2238 {
2239         return seq_open_net(inode, file, &unix_seq_ops,
2240                             sizeof(struct unix_iter_state));
2241 }
2242
2243 static const struct file_operations unix_seq_fops = {
2244         .owner          = THIS_MODULE,
2245         .open           = unix_seq_open,
2246         .read           = seq_read,
2247         .llseek         = seq_lseek,
2248         .release        = seq_release_net,
2249 };
2250
2251 #endif
2252
2253 static const struct net_proto_family unix_family_ops = {
2254         .family = PF_UNIX,
2255         .create = unix_create,
2256         .owner  = THIS_MODULE,
2257 };
2258
2259
2260 static int __net_init unix_net_init(struct net *net)
2261 {
2262         int error = -ENOMEM;
2263
2264         net->unx.sysctl_max_dgram_qlen = 10;
2265         if (unix_sysctl_register(net))
2266                 goto out;
2267
2268 #ifdef CONFIG_PROC_FS
2269         if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2270                 unix_sysctl_unregister(net);
2271                 goto out;
2272         }
2273 #endif
2274         error = 0;
2275 out:
2276         return error;
2277 }
2278
2279 static void __net_exit unix_net_exit(struct net *net)
2280 {
2281         unix_sysctl_unregister(net);
2282         proc_net_remove(net, "unix");
2283 }
2284
2285 static struct pernet_operations unix_net_ops = {
2286         .init = unix_net_init,
2287         .exit = unix_net_exit,
2288 };
2289
2290 static int __init af_unix_init(void)
2291 {
2292         int rc = -1;
2293         struct sk_buff *dummy_skb;
2294
2295         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2296
2297         rc = proto_register(&unix_proto, 1);
2298         if (rc != 0) {
2299                 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2300                        __func__);
2301                 goto out;
2302         }
2303
2304         sock_register(&unix_family_ops);
2305         register_pernet_subsys(&unix_net_ops);
2306 out:
2307         return rc;
2308 }
2309
2310 static void __exit af_unix_exit(void)
2311 {
2312         sock_unregister(PF_UNIX);
2313         proto_unregister(&unix_proto);
2314         unregister_pernet_subsys(&unix_net_ops);
2315 }
2316
2317 /* Earlier than device_initcall() so that other drivers invoking
2318    request_module() don't end up in a loop when modprobe tries
2319    to use a UNIX socket. But later than subsys_initcall() because
2320    we depend on stuff initialised there */
2321 fs_initcall(af_unix_init);
2322 module_exit(af_unix_exit);
2323
2324 MODULE_LICENSE("GPL");
2325 MODULE_ALIAS_NETPROTO(PF_UNIX);