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_t unix_nr_socks = ATOMIC_INIT(0);
 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(&wq->wait);
 320                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 321         }
 322         rcu_read_unlock();
 323 }
 324
 325 /* When dgram socket disconnects (or changes its peer), we clear its receive
 326  * queue of packets arrived from previous peer. First, it allows to do
 327  * flow control based only on wmem_alloc; second, sk connected to peer
 328  * may receive messages only from that peer. */
 329 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
 330 {
 331         if (!skb_queue_empty(&sk->sk_receive_queue)) {
 332                 skb_queue_purge(&sk->sk_receive_queue);
 333                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
 334
 335                 /* If one link of bidirectional dgram pipe is disconnected,
 336                  * we signal error. Messages are lost. Do not make this,
 337                  * when peer was not connected to us.
 338                  */
 339                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
 340                         other->sk_err = ECONNRESET;
 341                         other->sk_error_report(other);
 342                 }
 343         }
 344 }
 345
 346 static void unix_sock_destructor(struct sock *sk)
 347 {
 348         struct unix_sock *u = unix_sk(sk);
 349
 350         skb_queue_purge(&sk->sk_receive_queue);
 351
 352         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
 353         WARN_ON(!sk_unhashed(sk));
 354         WARN_ON(sk->sk_socket);
 355         if (!sock_flag(sk, SOCK_DEAD)) {
 356                 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
 357                 return;
 358         }
 359
 360         if (u->addr)
 361                 unix_release_addr(u->addr);
 362
 363         atomic_dec(&unix_nr_socks);
 364         local_bh_disable();
 365         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 366         local_bh_enable();
 367 #ifdef UNIX_REFCNT_DEBUG
 368         printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk,
 369                 atomic_read(&unix_nr_socks));
 370 #endif
 371 }
 372
 373 static int unix_release_sock(struct sock *sk, int embrion)
 374 {
 375         struct unix_sock *u = unix_sk(sk);
 376         struct dentry *dentry;
 377         struct vfsmount *mnt;
 378         struct sock *skpair;
 379         struct sk_buff *skb;
 380         int state;
 381
 382         unix_remove_socket(sk);
 383
 384         /* Clear state */
 385         unix_state_lock(sk);
 386         sock_orphan(sk);
 387         sk->sk_shutdown = SHUTDOWN_MASK;
 388         dentry       = u->dentry;
 389         u->dentry    = NULL;
 390         mnt          = u->mnt;
 391         u->mnt       = NULL;
 392         state = sk->sk_state;
 393         sk->sk_state = TCP_CLOSE;
 394         unix_state_unlock(sk);
 395
 396         wake_up_interruptible_all(&u->peer_wait);
 397
 398         skpair = unix_peer(sk);
 399
 400         if (skpair != NULL) {
 401                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
 402                         unix_state_lock(skpair);
 403                         /* No more writes */
 404                         skpair->sk_shutdown = SHUTDOWN_MASK;
 405                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 406                                 skpair->sk_err = ECONNRESET;
 407                         unix_state_unlock(skpair);
 408                         skpair->sk_state_change(skpair);
 409                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
 410                 }
 411                 sock_put(skpair); /* It may now die */
 412                 unix_peer(sk) = NULL;
 413         }
 414
 415         /* Try to flush out this socket. Throw out buffers at least */
 416
 417         while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 418                 if (state == TCP_LISTEN)
 419                         unix_release_sock(skb->sk, 1);
 420                 /* passed fds are erased in the kfree_skb hook        */
 421                 kfree_skb(skb);
 422         }
 423
 424         if (dentry) {
 425                 dput(dentry);
 426                 mntput(mnt);
 427         }
 428
 429         sock_put(sk);
 430
 431         /* ---- Socket is dead now and most probably destroyed ---- */
 432
 433         /*
 434          * Fixme: BSD difference: In BSD all sockets connected to use get
 435          *        ECONNRESET and we die on the spot. In Linux we behave
 436          *        like files and pipes do and wait for the last
 437          *        dereference.
 438          *
 439          * Can't we simply set sock->err?
 440          *
 441          *        What the above comment does talk about? --ANK(980817)
 442          */
 443
 444         if (unix_tot_inflight)
 445                 unix_gc();              /* Garbage collect fds */
 446
 447         return 0;
 448 }
 449
 450 static void init_peercred(struct sock *sk)
 451 {
 452         put_pid(sk->sk_peer_pid);
 453         if (sk->sk_peer_cred)
 454                 put_cred(sk->sk_peer_cred);
 455         sk->sk_peer_pid  = get_pid(task_tgid(current));
 456         sk->sk_peer_cred = get_current_cred();
 457 }
 458
 459 static void copy_peercred(struct sock *sk, struct sock *peersk)
 460 {
 461         put_pid(sk->sk_peer_pid);
 462         if (sk->sk_peer_cred)
 463                 put_cred(sk->sk_peer_cred);
 464         sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
 465         sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
 466 }
 467
 468 static int unix_listen(struct socket *sock, int backlog)
 469 {
 470         int err;
 471         struct sock *sk = sock->sk;
 472         struct unix_sock *u = unix_sk(sk);
 473         struct pid *old_pid = NULL;
 474         const struct cred *old_cred = NULL;
 475
 476         err = -EOPNOTSUPP;
 477         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
 478                 goto out;       /* Only stream/seqpacket sockets accept */
 479         err = -EINVAL;
 480         if (!u->addr)
 481                 goto out;       /* No listens on an unbound socket */
 482         unix_state_lock(sk);
 483         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
 484                 goto out_unlock;
 485         if (backlog > sk->sk_max_ack_backlog)
 486                 wake_up_interruptible_all(&u->peer_wait);
 487         sk->sk_max_ack_backlog  = backlog;
 488         sk->sk_state            = TCP_LISTEN;
 489         /* set credentials so connect can copy them */
 490         init_peercred(sk);
 491         err = 0;
 492
 493 out_unlock:
 494         unix_state_unlock(sk);
 495         put_pid(old_pid);
 496         if (old_cred)
 497                 put_cred(old_cred);
 498 out:
 499         return err;
 500 }
 501
 502 static int unix_release(struct socket *);
 503 static int unix_bind(struct socket *, struct sockaddr *, int);
 504 static int unix_stream_connect(struct socket *, struct sockaddr *,
 505                                int addr_len, int flags);
 506 static int unix_socketpair(struct socket *, struct socket *);
 507 static int unix_accept(struct socket *, struct socket *, int);
 508 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
 509 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
 510 static unsigned int unix_dgram_poll(struct file *, struct socket *,
 511                                     poll_table *);
 512 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
 513 static int unix_shutdown(struct socket *, int);
 514 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
 515                                struct msghdr *, size_t);
 516 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
 517                                struct msghdr *, size_t, int);
 518 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
 519                               struct msghdr *, size_t);
 520 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
 521                               struct msghdr *, size_t, int);
 522 static int unix_dgram_connect(struct socket *, struct sockaddr *,
 523                               int, int);
 524 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
 525                                   struct msghdr *, size_t);
 526
 527 static const struct proto_ops unix_stream_ops = {
 528         .family =       PF_UNIX,
 529         .owner =        THIS_MODULE,
 530         .release =      unix_release,
 531         .bind =         unix_bind,
 532         .connect =      unix_stream_connect,
 533         .socketpair =   unix_socketpair,
 534         .accept =       unix_accept,
 535         .getname =      unix_getname,
 536         .poll =         unix_poll,
 537         .ioctl =        unix_ioctl,
 538         .listen =       unix_listen,
 539         .shutdown =     unix_shutdown,
 540         .setsockopt =   sock_no_setsockopt,
 541         .getsockopt =   sock_no_getsockopt,
 542         .sendmsg =      unix_stream_sendmsg,
 543         .recvmsg =      unix_stream_recvmsg,
 544         .mmap =         sock_no_mmap,
 545         .sendpage =     sock_no_sendpage,
 546 };
 547
 548 static const struct proto_ops unix_dgram_ops = {
 549         .family =       PF_UNIX,
 550         .owner =        THIS_MODULE,
 551         .release =      unix_release,
 552         .bind =         unix_bind,
 553         .connect =      unix_dgram_connect,
 554         .socketpair =   unix_socketpair,
 555         .accept =       sock_no_accept,
 556         .getname =      unix_getname,
 557         .poll =         unix_dgram_poll,
 558         .ioctl =        unix_ioctl,
 559         .listen =       sock_no_listen,
 560         .shutdown =     unix_shutdown,
 561         .setsockopt =   sock_no_setsockopt,
 562         .getsockopt =   sock_no_getsockopt,
 563         .sendmsg =      unix_dgram_sendmsg,
 564         .recvmsg =      unix_dgram_recvmsg,
 565         .mmap =         sock_no_mmap,
 566         .sendpage =     sock_no_sendpage,
 567 };
 568
 569 static const struct proto_ops unix_seqpacket_ops = {
 570         .family =       PF_UNIX,
 571         .owner =        THIS_MODULE,
 572         .release =      unix_release,
 573         .bind =         unix_bind,
 574         .connect =      unix_stream_connect,
 575         .socketpair =   unix_socketpair,
 576         .accept =       unix_accept,
 577         .getname =      unix_getname,
 578         .poll =         unix_dgram_poll,
 579         .ioctl =        unix_ioctl,
 580         .listen =       unix_listen,
 581         .shutdown =     unix_shutdown,
 582         .setsockopt =   sock_no_setsockopt,
 583         .getsockopt =   sock_no_getsockopt,
 584         .sendmsg =      unix_seqpacket_sendmsg,
 585         .recvmsg =      unix_dgram_recvmsg,
 586         .mmap =         sock_no_mmap,
 587         .sendpage =     sock_no_sendpage,
 588 };
 589
 590 static struct proto unix_proto = {
 591         .name                   = "UNIX",
 592         .owner                  = THIS_MODULE,
 593         .obj_size               = sizeof(struct unix_sock),
 594 };
 595
 596 /*
 597  * AF_UNIX sockets do not interact with hardware, hence they
 598  * dont trigger interrupts - so it's safe for them to have
 599  * bh-unsafe locking for their sk_receive_queue.lock. Split off
 600  * this special lock-class by reinitializing the spinlock key:
 601  */
 602 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
 603
 604 static struct sock *unix_create1(struct net *net, struct socket *sock)
 605 {
 606         struct sock *sk = NULL;
 607         struct unix_sock *u;
 608
 609         atomic_inc(&unix_nr_socks);
 610         if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
 611                 goto out;
 612
 613         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
 614         if (!sk)
 615                 goto out;
 616
 617         sock_init_data(sock, sk);
 618         lockdep_set_class(&sk->sk_receive_queue.lock,
 619                                 &af_unix_sk_receive_queue_lock_key);
 620
 621         sk->sk_write_space      = unix_write_space;
 622         sk->sk_max_ack_backlog  = net->unx.sysctl_max_dgram_qlen;
 623         sk->sk_destruct         = unix_sock_destructor;
 624         u         = unix_sk(sk);
 625         u->dentry = NULL;
 626         u->mnt    = NULL;
 627         spin_lock_init(&u->lock);
 628         atomic_long_set(&u->inflight, 0);
 629         INIT_LIST_HEAD(&u->link);
 630         mutex_init(&u->readlock); /* single task reading lock */
 631         init_waitqueue_head(&u->peer_wait);
 632         unix_insert_socket(unix_sockets_unbound, sk);
 633 out:
 634         if (sk == NULL)
 635                 atomic_dec(&unix_nr_socks);
 636         else {
 637                 local_bh_disable();
 638                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 639                 local_bh_enable();
 640         }
 641         return sk;
 642 }
 643
 644 static int unix_create(struct net *net, struct socket *sock, int protocol,
 645                        int kern)
 646 {
 647         if (protocol && protocol != PF_UNIX)
 648                 return -EPROTONOSUPPORT;
 649
 650         sock->state = SS_UNCONNECTED;
 651
 652         switch (sock->type) {
 653         case SOCK_STREAM:
 654                 sock->ops = &unix_stream_ops;
 655                 break;
 656                 /*
 657                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
 658                  *      nothing uses it.
 659                  */
 660         case SOCK_RAW:
 661                 sock->type = SOCK_DGRAM;
 662         case SOCK_DGRAM:
 663                 sock->ops = &unix_dgram_ops;
 664                 break;
 665         case SOCK_SEQPACKET:
 666                 sock->ops = &unix_seqpacket_ops;
 667                 break;
 668         default:
 669                 return -ESOCKTNOSUPPORT;
 670         }
 671
 672         return unix_create1(net, sock) ? 0 : -ENOMEM;
 673 }
 674
 675 static int unix_release(struct socket *sock)
 676 {
 677         struct sock *sk = sock->sk;
 678
 679         if (!sk)
 680                 return 0;
 681
 682         sock->sk = NULL;
 683
 684         return unix_release_sock(sk, 0);
 685 }
 686
 687 static int unix_autobind(struct socket *sock)
 688 {
 689         struct sock *sk = sock->sk;
 690         struct net *net = sock_net(sk);
 691         struct unix_sock *u = unix_sk(sk);
 692         static u32 ordernum = 1;
 693         struct unix_address *addr;
 694         int err;
 695         unsigned int retries = 0;
 696
 697         mutex_lock(&u->readlock);
 698
 699         err = 0;
 700         if (u->addr)
 701                 goto out;
 702
 703         err = -ENOMEM;
 704         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
 705         if (!addr)
 706                 goto out;
 707
 708         addr->name->sun_family = AF_UNIX;
 709         atomic_set(&addr->refcnt, 1);
 710
 711 retry:
 712         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
 713         addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
 714
 715         spin_lock(&unix_table_lock);
 716         ordernum = (ordernum+1)&0xFFFFF;
 717
 718         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
 719                                       addr->hash)) {
 720                 spin_unlock(&unix_table_lock);
 721                 /*
 722                  * __unix_find_socket_byname() may take long time if many names
 723                  * are already in use.
 724                  */
 725                 cond_resched();
 726                 /* Give up if all names seems to be in use. */
 727                 if (retries++ == 0xFFFFF) {
 728                         err = -ENOSPC;
 729                         kfree(addr);
 730                         goto out;
 731                 }
 732                 goto retry;
 733         }
 734         addr->hash ^= sk->sk_type;
 735
 736         __unix_remove_socket(sk);
 737         u->addr = addr;
 738         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
 739         spin_unlock(&unix_table_lock);
 740         err = 0;
 741
 742 out:    mutex_unlock(&u->readlock);
 743         return err;
 744 }
 745
 746 static struct sock *unix_find_other(struct net *net,
 747                                     struct sockaddr_un *sunname, int len,
 748                                     int type, unsigned hash, int *error)
 749 {
 750         struct sock *u;
 751         struct path path;
 752         int err = 0;
 753
 754         if (sunname->sun_path[0]) {
 755                 struct inode *inode;
 756                 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
 757                 if (err)
 758                         goto fail;
 759                 inode = path.dentry->d_inode;
 760                 err = inode_permission(inode, MAY_WRITE);
 761                 if (err)
 762                         goto put_fail;
 763
 764                 err = -ECONNREFUSED;
 765                 if (!S_ISSOCK(inode->i_mode))
 766                         goto put_fail;
 767                 u = unix_find_socket_byinode(inode);
 768                 if (!u)
 769                         goto put_fail;
 770
 771                 if (u->sk_type == type)
 772                         touch_atime(path.mnt, path.dentry);
 773
 774                 path_put(&path);
 775
 776                 err = -EPROTOTYPE;
 777                 if (u->sk_type != type) {
 778                         sock_put(u);
 779                         goto fail;
 780                 }
 781         } else {
 782                 err = -ECONNREFUSED;
 783                 u = unix_find_socket_byname(net, sunname, len, type, hash);
 784                 if (u) {
 785                         struct dentry *dentry;
 786                         dentry = unix_sk(u)->dentry;
 787                         if (dentry)
 788                                 touch_atime(unix_sk(u)->mnt, dentry);
 789                 } else
 790                         goto fail;
 791         }
 792         return u;
 793
 794 put_fail:
 795         path_put(&path);
 796 fail:
 797         *error = err;
 798         return NULL;
 799 }
 800
 801
 802 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 803 {
 804         struct sock *sk = sock->sk;
 805         struct net *net = sock_net(sk);
 806         struct unix_sock *u = unix_sk(sk);
 807         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
 808         struct dentry *dentry = NULL;
 809         struct nameidata nd;
 810         int err;
 811         unsigned hash;
 812         struct unix_address *addr;
 813         struct hlist_head *list;
 814
 815         err = -EINVAL;
 816         if (sunaddr->sun_family != AF_UNIX)
 817                 goto out;
 818
 819         if (addr_len == sizeof(short)) {
 820                 err = unix_autobind(sock);
 821                 goto out;
 822         }
 823
 824         err = unix_mkname(sunaddr, addr_len, &hash);
 825         if (err < 0)
 826                 goto out;
 827         addr_len = err;
 828
 829         mutex_lock(&u->readlock);
 830
 831         err = -EINVAL;
 832         if (u->addr)
 833                 goto out_up;
 834
 835         err = -ENOMEM;
 836         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
 837         if (!addr)
 838                 goto out_up;
 839
 840         memcpy(addr->name, sunaddr, addr_len);
 841         addr->len = addr_len;
 842         addr->hash = hash ^ sk->sk_type;
 843         atomic_set(&addr->refcnt, 1);
 844
 845         if (sunaddr->sun_path[0]) {
 846                 unsigned int mode;
 847                 err = 0;
 848                 /*
 849                  * Get the parent directory, calculate the hash for last
 850                  * component.
 851                  */
 852                 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
 853                 if (err)
 854                         goto out_mknod_parent;
 855
 856                 dentry = lookup_create(&nd, 0);
 857                 err = PTR_ERR(dentry);
 858                 if (IS_ERR(dentry))
 859                         goto out_mknod_unlock;
 860
 861                 /*
 862                  * All right, let's create it.
 863                  */
 864                 mode = S_IFSOCK |
 865                        (SOCK_INODE(sock)->i_mode & ~current_umask());
 866                 err = mnt_want_write(nd.path.mnt);
 867                 if (err)
 868                         goto out_mknod_dput;
 869                 err = security_path_mknod(&nd.path, dentry, mode, 0);
 870                 if (err)
 871                         goto out_mknod_drop_write;
 872                 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
 873 out_mknod_drop_write:
 874                 mnt_drop_write(nd.path.mnt);
 875                 if (err)
 876                         goto out_mknod_dput;
 877                 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 878                 dput(nd.path.dentry);
 879                 nd.path.dentry = dentry;
 880
 881                 addr->hash = UNIX_HASH_SIZE;
 882         }
 883
 884         spin_lock(&unix_table_lock);
 885
 886         if (!sunaddr->sun_path[0]) {
 887                 err = -EADDRINUSE;
 888                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
 889                                               sk->sk_type, hash)) {
 890                         unix_release_addr(addr);
 891                         goto out_unlock;
 892                 }
 893
 894                 list = &unix_socket_table[addr->hash];
 895         } else {
 896                 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
 897                 u->dentry = nd.path.dentry;
 898                 u->mnt    = nd.path.mnt;
 899         }
 900
 901         err = 0;
 902         __unix_remove_socket(sk);
 903         u->addr = addr;
 904         __unix_insert_socket(list, sk);
 905
 906 out_unlock:
 907         spin_unlock(&unix_table_lock);
 908 out_up:
 909         mutex_unlock(&u->readlock);
 910 out:
 911         return err;
 912
 913 out_mknod_dput:
 914         dput(dentry);
 915 out_mknod_unlock:
 916         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 917         path_put(&nd.path);
 918 out_mknod_parent:
 919         if (err == -EEXIST)
 920                 err = -EADDRINUSE;
 921         unix_release_addr(addr);
 922         goto out_up;
 923 }
 924
 925 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
 926 {
 927         if (unlikely(sk1 == sk2) || !sk2) {
 928                 unix_state_lock(sk1);
 929                 return;
 930         }
 931         if (sk1 < sk2) {
 932                 unix_state_lock(sk1);
 933                 unix_state_lock_nested(sk2);
 934         } else {
 935                 unix_state_lock(sk2);
 936                 unix_state_lock_nested(sk1);
 937         }
 938 }
 939
 940 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
 941 {
 942         if (unlikely(sk1 == sk2) || !sk2) {
 943                 unix_state_unlock(sk1);
 944                 return;
 945         }
 946         unix_state_unlock(sk1);
 947         unix_state_unlock(sk2);
 948 }
 949
 950 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 951                               int alen, int flags)
 952 {
 953         struct sock *sk = sock->sk;
 954         struct net *net = sock_net(sk);
 955         struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
 956         struct sock *other;
 957         unsigned hash;
 958         int err;
 959
 960         if (addr->sa_family != AF_UNSPEC) {
 961                 err = unix_mkname(sunaddr, alen, &hash);
 962                 if (err < 0)
 963                         goto out;
 964                 alen = err;
 965
 966                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
 967                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
 968                         goto out;
 969
 970 restart:
 971                 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
 972                 if (!other)
 973                         goto out;
 974
 975                 unix_state_double_lock(sk, other);
 976
 977                 /* Apparently VFS overslept socket death. Retry. */
 978                 if (sock_flag(other, SOCK_DEAD)) {
 979                         unix_state_double_unlock(sk, other);
 980                         sock_put(other);
 981                         goto restart;
 982                 }
 983
 984                 err = -EPERM;
 985                 if (!unix_may_send(sk, other))
 986                         goto out_unlock;
 987
 988                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
 989                 if (err)
 990                         goto out_unlock;
 991
 992         } else {
 993                 /*
 994                  *      1003.1g breaking connected state with AF_UNSPEC
 995                  */
 996                 other = NULL;
 997                 unix_state_double_lock(sk, other);
 998         }
 999
1000         /*
1001          * If it was connected, reconnect.
1002          */
1003         if (unix_peer(sk)) {
1004                 struct sock *old_peer = unix_peer(sk);
1005                 unix_peer(sk) = other;
1006                 unix_state_double_unlock(sk, other);
1007
1008                 if (other != old_peer)
1009                         unix_dgram_disconnected(sk, old_peer);
1010                 sock_put(old_peer);
1011         } else {
1012                 unix_peer(sk) = other;
1013                 unix_state_double_unlock(sk, other);
1014         }
1015         return 0;
1016
1017 out_unlock:
1018         unix_state_double_unlock(sk, other);
1019         sock_put(other);
1020 out:
1021         return err;
1022 }
1023
1024 static long unix_wait_for_peer(struct sock *other, long timeo)
1025 {
1026         struct unix_sock *u = unix_sk(other);
1027         int sched;
1028         DEFINE_WAIT(wait);
1029
1030         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1031
1032         sched = !sock_flag(other, SOCK_DEAD) &&
1033                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1034                 unix_recvq_full(other);
1035
1036         unix_state_unlock(other);
1037
1038         if (sched)
1039                 timeo = schedule_timeout(timeo);
1040
1041         finish_wait(&u->peer_wait, &wait);
1042         return timeo;
1043 }
1044
1045 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1046                                int addr_len, int flags)
1047 {
1048         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1049         struct sock *sk = sock->sk;
1050         struct net *net = sock_net(sk);
1051         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1052         struct sock *newsk = NULL;
1053         struct sock *other = NULL;
1054         struct sk_buff *skb = NULL;
1055         unsigned hash;
1056         int st;
1057         int err;
1058         long timeo;
1059
1060         err = unix_mkname(sunaddr, addr_len, &hash);
1061         if (err < 0)
1062                 goto out;
1063         addr_len = err;
1064
1065         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1066             (err = unix_autobind(sock)) != 0)
1067                 goto out;
1068
1069         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1070
1071         /* First of all allocate resources.
1072            If we will make it after state is locked,
1073            we will have to recheck all again in any case.
1074          */
1075
1076         err = -ENOMEM;
1077
1078         /* create new sock for complete connection */
1079         newsk = unix_create1(sock_net(sk), NULL);
1080         if (newsk == NULL)
1081                 goto out;
1082
1083         /* Allocate skb for sending to listening sock */
1084         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1085         if (skb == NULL)
1086                 goto out;
1087
1088 restart:
1089         /*  Find listening sock. */
1090         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1091         if (!other)
1092                 goto out;
1093
1094         /* Latch state of peer */
1095         unix_state_lock(other);
1096
1097         /* Apparently VFS overslept socket death. Retry. */
1098         if (sock_flag(other, SOCK_DEAD)) {
1099                 unix_state_unlock(other);
1100                 sock_put(other);
1101                 goto restart;
1102         }
1103
1104         err = -ECONNREFUSED;
1105         if (other->sk_state != TCP_LISTEN)
1106                 goto out_unlock;
1107         if (other->sk_shutdown & RCV_SHUTDOWN)
1108                 goto out_unlock;
1109
1110         if (unix_recvq_full(other)) {
1111                 err = -EAGAIN;
1112                 if (!timeo)
1113                         goto out_unlock;
1114
1115                 timeo = unix_wait_for_peer(other, timeo);
1116
1117                 err = sock_intr_errno(timeo);
1118                 if (signal_pending(current))
1119                         goto out;
1120                 sock_put(other);
1121                 goto restart;
1122         }
1123
1124         /* Latch our state.
1125
1126            It is tricky place. We need to grab write lock and cannot
1127            drop lock on peer. It is dangerous because deadlock is
1128            possible. Connect to self case and simultaneous
1129            attempt to connect are eliminated by checking socket
1130            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1131            check this before attempt to grab lock.
1132
1133            Well, and we have to recheck the state after socket locked.
1134          */
1135         st = sk->sk_state;
1136
1137         switch (st) {
1138         case TCP_CLOSE:
1139                 /* This is ok... continue with connect */
1140                 break;
1141         case TCP_ESTABLISHED:
1142                 /* Socket is already connected */
1143                 err = -EISCONN;
1144                 goto out_unlock;
1145         default:
1146                 err = -EINVAL;
1147                 goto out_unlock;
1148         }
1149
1150         unix_state_lock_nested(sk);
1151
1152         if (sk->sk_state != st) {
1153                 unix_state_unlock(sk);
1154                 unix_state_unlock(other);
1155                 sock_put(other);
1156                 goto restart;
1157         }
1158
1159         err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1160         if (err) {
1161                 unix_state_unlock(sk);
1162                 goto out_unlock;
1163         }
1164
1165         /* The way is open! Fastly set all the necessary fields... */
1166
1167         sock_hold(sk);
1168         unix_peer(newsk)        = sk;
1169         newsk->sk_state         = TCP_ESTABLISHED;
1170         newsk->sk_type          = sk->sk_type;
1171         init_peercred(newsk);
1172         newu = unix_sk(newsk);
1173         newsk->sk_wq            = &newu->peer_wq;
1174         otheru = unix_sk(other);
1175
1176         /* copy address information from listening to new sock*/
1177         if (otheru->addr) {
1178                 atomic_inc(&otheru->addr->refcnt);
1179                 newu->addr = otheru->addr;
1180         }
1181         if (otheru->dentry) {
1182                 newu->dentry    = dget(otheru->dentry);
1183                 newu->mnt       = mntget(otheru->mnt);
1184         }
1185
1186         /* Set credentials */
1187         copy_peercred(sk, other);
1188
1189         sock->state     = SS_CONNECTED;
1190         sk->sk_state    = TCP_ESTABLISHED;
1191         sock_hold(newsk);
1192
1193         smp_mb__after_atomic_inc();     /* sock_hold() does an atomic_inc() */
1194         unix_peer(sk)   = newsk;
1195
1196         unix_state_unlock(sk);
1197
1198         /* take ten and and send info to listening sock */
1199         spin_lock(&other->sk_receive_queue.lock);
1200         __skb_queue_tail(&other->sk_receive_queue, skb);
1201         spin_unlock(&other->sk_receive_queue.lock);
1202         unix_state_unlock(other);
1203         other->sk_data_ready(other, 0);
1204         sock_put(other);
1205         return 0;
1206
1207 out_unlock:
1208         if (other)
1209                 unix_state_unlock(other);
1210
1211 out:
1212         kfree_skb(skb);
1213         if (newsk)
1214                 unix_release_sock(newsk, 0);
1215         if (other)
1216                 sock_put(other);
1217         return err;
1218 }
1219
1220 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1221 {
1222         struct sock *ska = socka->sk, *skb = sockb->sk;
1223
1224         /* Join our sockets back to back */
1225         sock_hold(ska);
1226         sock_hold(skb);
1227         unix_peer(ska) = skb;
1228         unix_peer(skb) = ska;
1229         init_peercred(ska);
1230         init_peercred(skb);
1231
1232         if (ska->sk_type != SOCK_DGRAM) {
1233                 ska->sk_state = TCP_ESTABLISHED;
1234                 skb->sk_state = TCP_ESTABLISHED;
1235                 socka->state  = SS_CONNECTED;
1236                 sockb->state  = SS_CONNECTED;
1237         }
1238         return 0;
1239 }
1240
1241 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1242 {
1243         struct sock *sk = sock->sk;
1244         struct sock *tsk;
1245         struct sk_buff *skb;
1246         int err;
1247
1248         err = -EOPNOTSUPP;
1249         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1250                 goto out;
1251
1252         err = -EINVAL;
1253         if (sk->sk_state != TCP_LISTEN)
1254                 goto out;
1255
1256         /* If socket state is TCP_LISTEN it cannot change (for now...),
1257          * so that no locks are necessary.
1258          */
1259
1260         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1261         if (!skb) {
1262                 /* This means receive shutdown. */
1263                 if (err == 0)
1264                         err = -EINVAL;
1265                 goto out;
1266         }
1267
1268         tsk = skb->sk;
1269         skb_free_datagram(sk, skb);
1270         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1271
1272         /* attach accepted sock to socket */
1273         unix_state_lock(tsk);
1274         newsock->state = SS_CONNECTED;
1275         sock_graft(tsk, newsock);
1276         unix_state_unlock(tsk);
1277         return 0;
1278
1279 out:
1280         return err;
1281 }
1282
1283
1284 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1285 {
1286         struct sock *sk = sock->sk;
1287         struct unix_sock *u;
1288         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1289         int err = 0;
1290
1291         if (peer) {
1292                 sk = unix_peer_get(sk);
1293
1294                 err = -ENOTCONN;
1295                 if (!sk)
1296                         goto out;
1297                 err = 0;
1298         } else {
1299                 sock_hold(sk);
1300         }
1301
1302         u = unix_sk(sk);
1303         unix_state_lock(sk);
1304         if (!u->addr) {
1305                 sunaddr->sun_family = AF_UNIX;
1306                 sunaddr->sun_path[0] = 0;
1307                 *uaddr_len = sizeof(short);
1308         } else {
1309                 struct unix_address *addr = u->addr;
1310
1311                 *uaddr_len = addr->len;
1312                 memcpy(sunaddr, addr->name, *uaddr_len);
1313         }
1314         unix_state_unlock(sk);
1315         sock_put(sk);
1316 out:
1317         return err;
1318 }
1319
1320 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1321 {
1322         int i;
1323
1324         scm->fp = UNIXCB(skb).fp;
1325         UNIXCB(skb).fp = NULL;
1326
1327         for (i = scm->fp->count-1; i >= 0; i--)
1328                 unix_notinflight(scm->fp->fp[i]);
1329 }
1330
1331 static void unix_destruct_scm(struct sk_buff *skb)
1332 {
1333         struct scm_cookie scm;
1334         memset(&scm, 0, sizeof(scm));
1335         scm.pid  = UNIXCB(skb).pid;
1336         scm.cred = UNIXCB(skb).cred;
1337         if (UNIXCB(skb).fp)
1338                 unix_detach_fds(&scm, skb);
1339
1340         /* Alas, it calls VFS */
1341         /* So fscking what? fput() had been SMP-safe since the last Summer */
1342         scm_destroy(&scm);
1343         sock_wfree(skb);
1344 }
1345
1346 #define MAX_RECURSION_LEVEL 4
1347
1348 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1349 {
1350         int i;
1351         unsigned char max_level = 0;
1352         int unix_sock_count = 0;
1353
1354         for (i = scm->fp->count - 1; i >= 0; i--) {
1355                 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1356
1357                 if (sk) {
1358                         unix_sock_count++;
1359                         max_level = max(max_level,
1360                                         unix_sk(sk)->recursion_level);
1361                 }
1362         }
1363         if (unlikely(max_level > MAX_RECURSION_LEVEL))
1364                 return -ETOOMANYREFS;
1365
1366         /*
1367          * Need to duplicate file references for the sake of garbage
1368          * collection.  Otherwise a socket in the fps might become a
1369          * candidate for GC while the skb is not yet queued.
1370          */
1371         UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1372         if (!UNIXCB(skb).fp)
1373                 return -ENOMEM;
1374
1375         if (unix_sock_count) {
1376                 for (i = scm->fp->count - 1; i >= 0; i--)
1377                         unix_inflight(scm->fp->fp[i]);
1378         }
1379         return max_level;
1380 }
1381
1382 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1383 {
1384         int err = 0;
1385         UNIXCB(skb).pid  = get_pid(scm->pid);
1386         UNIXCB(skb).cred = get_cred(scm->cred);
1387         UNIXCB(skb).fp = NULL;
1388         if (scm->fp && send_fds)
1389                 err = unix_attach_fds(scm, skb);
1390
1391         skb->destructor = unix_destruct_scm;
1392         return err;
1393 }
1394
1395 /*
1396  *      Send AF_UNIX data.
1397  */
1398
1399 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1400                               struct msghdr *msg, size_t len)
1401 {
1402         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1403         struct sock *sk = sock->sk;
1404         struct net *net = sock_net(sk);
1405         struct unix_sock *u = unix_sk(sk);
1406         struct sockaddr_un *sunaddr = msg->msg_name;
1407         struct sock *other = NULL;
1408         int namelen = 0; /* fake GCC */
1409         int err;
1410         unsigned hash;
1411         struct sk_buff *skb;
1412         long timeo;
1413         struct scm_cookie tmp_scm;
1414         int max_level;
1415
1416         if (NULL == siocb->scm)
1417                 siocb->scm = &tmp_scm;
1418         wait_for_unix_gc();
1419         err = scm_send(sock, msg, siocb->scm);
1420         if (err < 0)
1421                 return err;
1422
1423         err = -EOPNOTSUPP;
1424         if (msg->msg_flags&MSG_OOB)
1425                 goto out;
1426
1427         if (msg->msg_namelen) {
1428                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1429                 if (err < 0)
1430                         goto out;
1431                 namelen = err;
1432         } else {
1433                 sunaddr = NULL;
1434                 err = -ENOTCONN;
1435                 other = unix_peer_get(sk);
1436                 if (!other)
1437                         goto out;
1438         }
1439
1440         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1441             && (err = unix_autobind(sock)) != 0)
1442                 goto out;
1443
1444         err = -EMSGSIZE;
1445         if (len > sk->sk_sndbuf - 32)
1446                 goto out;
1447
1448         skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1449         if (skb == NULL)
1450                 goto out;
1451
1452         err = unix_scm_to_skb(siocb->scm, skb, true);
1453         if (err < 0)
1454                 goto out_free;
1455         max_level = err + 1;
1456         unix_get_secdata(siocb->scm, skb);
1457
1458         skb_reset_transport_header(skb);
1459         err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1460         if (err)
1461                 goto out_free;
1462
1463         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1464
1465 restart:
1466         if (!other) {
1467                 err = -ECONNRESET;
1468                 if (sunaddr == NULL)
1469                         goto out_free;
1470
1471                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1472                                         hash, &err);
1473                 if (other == NULL)
1474                         goto out_free;
1475         }
1476
1477         unix_state_lock(other);
1478         err = -EPERM;
1479         if (!unix_may_send(sk, other))
1480                 goto out_unlock;
1481
1482         if (sock_flag(other, SOCK_DEAD)) {
1483                 /*
1484                  *      Check with 1003.1g - what should
1485                  *      datagram error
1486                  */
1487                 unix_state_unlock(other);
1488                 sock_put(other);
1489
1490                 err = 0;
1491                 unix_state_lock(sk);
1492                 if (unix_peer(sk) == other) {
1493                         unix_peer(sk) = NULL;
1494                         unix_state_unlock(sk);
1495
1496                         unix_dgram_disconnected(sk, other);
1497                         sock_put(other);
1498                         err = -ECONNREFUSED;
1499                 } else {
1500                         unix_state_unlock(sk);
1501                 }
1502
1503                 other = NULL;
1504                 if (err)
1505                         goto out_free;
1506                 goto restart;
1507         }
1508
1509         err = -EPIPE;
1510         if (other->sk_shutdown & RCV_SHUTDOWN)
1511                 goto out_unlock;
1512
1513         if (sk->sk_type != SOCK_SEQPACKET) {
1514                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1515                 if (err)
1516                         goto out_unlock;
1517         }
1518
1519         if (unix_peer(other) != sk && unix_recvq_full(other)) {
1520                 if (!timeo) {
1521                         err = -EAGAIN;
1522                         goto out_unlock;
1523                 }
1524
1525                 timeo = unix_wait_for_peer(other, timeo);
1526
1527                 err = sock_intr_errno(timeo);
1528                 if (signal_pending(current))
1529                         goto out_free;
1530
1531                 goto restart;
1532         }
1533
1534         skb_queue_tail(&other->sk_receive_queue, skb);
1535         if (max_level > unix_sk(other)->recursion_level)
1536                 unix_sk(other)->recursion_level = max_level;
1537         unix_state_unlock(other);
1538         other->sk_data_ready(other, len);
1539         sock_put(other);
1540         scm_destroy(siocb->scm);
1541         return len;
1542
1543 out_unlock:
1544         unix_state_unlock(other);
1545 out_free:
1546         kfree_skb(skb);
1547 out:
1548         if (other)
1549                 sock_put(other);
1550         scm_destroy(siocb->scm);
1551         return err;
1552 }
1553
1554
1555 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1556                                struct msghdr *msg, size_t len)
1557 {
1558         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1559         struct sock *sk = sock->sk;
1560         struct sock *other = NULL;
1561         struct sockaddr_un *sunaddr = msg->msg_name;
1562         int err, size;
1563         struct sk_buff *skb;
1564         int sent = 0;
1565         struct scm_cookie tmp_scm;
1566         bool fds_sent = false;
1567         int max_level;
1568
1569         if (NULL == siocb->scm)
1570                 siocb->scm = &tmp_scm;
1571         wait_for_unix_gc();
1572         err = scm_send(sock, msg, siocb->scm);
1573         if (err < 0)
1574                 return err;
1575
1576         err = -EOPNOTSUPP;
1577         if (msg->msg_flags&MSG_OOB)
1578                 goto out_err;
1579
1580         if (msg->msg_namelen) {
1581                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1582                 goto out_err;
1583         } else {
1584                 sunaddr = NULL;
1585                 err = -ENOTCONN;
1586                 other = unix_peer(sk);
1587                 if (!other)
1588                         goto out_err;
1589         }
1590
1591         if (sk->sk_shutdown & SEND_SHUTDOWN)
1592                 goto pipe_err;
1593
1594         while (sent < len) {
1595                 /*
1596                  *      Optimisation for the fact that under 0.01% of X
1597                  *      messages typically need breaking up.
1598                  */
1599
1600                 size = len-sent;
1601
1602                 /* Keep two messages in the pipe so it schedules better */
1603                 if (size > ((sk->sk_sndbuf >> 1) - 64))
1604                         size = (sk->sk_sndbuf >> 1) - 64;
1605
1606                 if (size > SKB_MAX_ALLOC)
1607                         size = SKB_MAX_ALLOC;
1608
1609                 /*
1610                  *      Grab a buffer
1611                  */
1612
1613                 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1614                                           &err);
1615
1616                 if (skb == NULL)
1617                         goto out_err;
1618
1619                 /*
1620                  *      If you pass two values to the sock_alloc_send_skb
1621                  *      it tries to grab the large buffer with GFP_NOFS
1622                  *      (which can fail easily), and if it fails grab the
1623                  *      fallback size buffer which is under a page and will
1624                  *      succeed. [Alan]
1625                  */
1626                 size = min_t(int, size, skb_tailroom(skb));
1627
1628
1629                 /* Only send the fds in the first buffer */
1630                 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1631                 if (err < 0) {
1632                         kfree_skb(skb);
1633                         goto out_err;
1634                 }
1635                 max_level = err + 1;
1636                 fds_sent = true;
1637
1638                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1639                 if (err) {
1640                         kfree_skb(skb);
1641                         goto out_err;
1642                 }
1643
1644                 unix_state_lock(other);
1645
1646                 if (sock_flag(other, SOCK_DEAD) ||
1647                     (other->sk_shutdown & RCV_SHUTDOWN))
1648                         goto pipe_err_free;
1649
1650                 skb_queue_tail(&other->sk_receive_queue, skb);
1651                 if (max_level > unix_sk(other)->recursion_level)
1652                         unix_sk(other)->recursion_level = max_level;
1653                 unix_state_unlock(other);
1654                 other->sk_data_ready(other, size);
1655                 sent += size;
1656         }
1657
1658         scm_destroy(siocb->scm);
1659         siocb->scm = NULL;
1660
1661         return sent;
1662
1663 pipe_err_free:
1664         unix_state_unlock(other);
1665         kfree_skb(skb);
1666 pipe_err:
1667         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1668                 send_sig(SIGPIPE, current, 0);
1669         err = -EPIPE;
1670 out_err:
1671         scm_destroy(siocb->scm);
1672         siocb->scm = NULL;
1673         return sent ? : err;
1674 }
1675
1676 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1677                                   struct msghdr *msg, size_t len)
1678 {
1679         int err;
1680         struct sock *sk = sock->sk;
1681
1682         err = sock_error(sk);
1683         if (err)
1684                 return err;
1685
1686         if (sk->sk_state != TCP_ESTABLISHED)
1687                 return -ENOTCONN;
1688
1689         if (msg->msg_namelen)
1690                 msg->msg_namelen = 0;
1691
1692         return unix_dgram_sendmsg(kiocb, sock, msg, len);
1693 }
1694
1695 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1696 {
1697         struct unix_sock *u = unix_sk(sk);
1698
1699         msg->msg_namelen = 0;
1700         if (u->addr) {
1701                 msg->msg_namelen = u->addr->len;
1702                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1703         }
1704 }
1705
1706 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1707                               struct msghdr *msg, size_t size,
1708                               int flags)
1709 {
1710         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1711         struct scm_cookie tmp_scm;
1712         struct sock *sk = sock->sk;
1713         struct unix_sock *u = unix_sk(sk);
1714         int noblock = flags & MSG_DONTWAIT;
1715         struct sk_buff *skb;
1716         int err;
1717
1718         err = -EOPNOTSUPP;
1719         if (flags&MSG_OOB)
1720                 goto out;
1721
1722         msg->msg_namelen = 0;
1723
1724         mutex_lock(&u->readlock);
1725
1726         skb = skb_recv_datagram(sk, flags, noblock, &err);
1727         if (!skb) {
1728                 unix_state_lock(sk);
1729                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1730                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1731                     (sk->sk_shutdown & RCV_SHUTDOWN))
1732                         err = 0;
1733                 unix_state_unlock(sk);
1734                 goto out_unlock;
1735         }
1736
1737         wake_up_interruptible_sync(&u->peer_wait);
1738
1739         if (msg->msg_name)
1740                 unix_copy_addr(msg, skb->sk);
1741
1742         if (size > skb->len)
1743                 size = skb->len;
1744         else if (size < skb->len)
1745                 msg->msg_flags |= MSG_TRUNC;
1746
1747         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1748         if (err)
1749                 goto out_free;
1750
1751         if (!siocb->scm) {
1752                 siocb->scm = &tmp_scm;
1753                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1754         }
1755         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1756         unix_set_secdata(siocb->scm, skb);
1757
1758         if (!(flags & MSG_PEEK)) {
1759                 if (UNIXCB(skb).fp)
1760                         unix_detach_fds(siocb->scm, skb);
1761         } else {
1762                 /* It is questionable: on PEEK we could:
1763                    - do not return fds - good, but too simple 8)
1764                    - return fds, and do not return them on read (old strategy,
1765                      apparently wrong)
1766                    - clone fds (I chose it for now, it is the most universal
1767                      solution)
1768
1769                    POSIX 1003.1g does not actually define this clearly
1770                    at all. POSIX 1003.1g doesn't define a lot of things
1771                    clearly however!
1772
1773                 */
1774                 if (UNIXCB(skb).fp)
1775                         siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1776         }
1777         err = size;
1778
1779         scm_recv(sock, msg, siocb->scm, flags);
1780
1781 out_free:
1782         skb_free_datagram(sk, skb);
1783 out_unlock:
1784         mutex_unlock(&u->readlock);
1785 out:
1786         return err;
1787 }
1788
1789 /*
1790  *      Sleep until data has arrive. But check for races..
1791  */
1792
1793 static long unix_stream_data_wait(struct sock *sk, long timeo)
1794 {
1795         DEFINE_WAIT(wait);
1796
1797         unix_state_lock(sk);
1798
1799         for (;;) {
1800                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1801
1802                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1803                     sk->sk_err ||
1804                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
1805                     signal_pending(current) ||
1806                     !timeo)
1807                         break;
1808
1809                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1810                 unix_state_unlock(sk);
1811                 timeo = schedule_timeout(timeo);
1812                 unix_state_lock(sk);
1813                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1814         }
1815
1816         finish_wait(sk_sleep(sk), &wait);
1817         unix_state_unlock(sk);
1818         return timeo;
1819 }
1820
1821
1822
1823 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1824                                struct msghdr *msg, size_t size,
1825                                int flags)
1826 {
1827         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1828         struct scm_cookie tmp_scm;
1829         struct sock *sk = sock->sk;
1830         struct unix_sock *u = unix_sk(sk);
1831         struct sockaddr_un *sunaddr = msg->msg_name;
1832         int copied = 0;
1833         int check_creds = 0;
1834         int target;
1835         int err = 0;
1836         long timeo;
1837
1838         err = -EINVAL;
1839         if (sk->sk_state != TCP_ESTABLISHED)
1840                 goto out;
1841
1842         err = -EOPNOTSUPP;
1843         if (flags&MSG_OOB)
1844                 goto out;
1845
1846         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1847         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1848
1849         msg->msg_namelen = 0;
1850
1851         /* Lock the socket to prevent queue disordering
1852          * while sleeps in memcpy_tomsg
1853          */
1854
1855         if (!siocb->scm) {
1856                 siocb->scm = &tmp_scm;
1857                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1858         }
1859
1860         mutex_lock(&u->readlock);
1861
1862         do {
1863                 int chunk;
1864                 struct sk_buff *skb;
1865
1866                 unix_state_lock(sk);
1867                 skb = skb_dequeue(&sk->sk_receive_queue);
1868                 if (skb == NULL) {
1869                         unix_sk(sk)->recursion_level = 0;
1870                         if (copied >= target)
1871                                 goto unlock;
1872
1873                         /*
1874                          *      POSIX 1003.1g mandates this order.
1875                          */
1876
1877                         err = sock_error(sk);
1878                         if (err)
1879                                 goto unlock;
1880                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1881                                 goto unlock;
1882
1883                         unix_state_unlock(sk);
1884                         err = -EAGAIN;
1885                         if (!timeo)
1886                                 break;
1887                         mutex_unlock(&u->readlock);
1888
1889                         timeo = unix_stream_data_wait(sk, timeo);
1890
1891                         if (signal_pending(current)) {
1892                                 err = sock_intr_errno(timeo);
1893                                 goto out;
1894                         }
1895                         mutex_lock(&u->readlock);
1896                         continue;
1897  unlock:
1898                         unix_state_unlock(sk);
1899                         break;
1900                 }
1901                 unix_state_unlock(sk);
1902
1903                 if (check_creds) {
1904                         /* Never glue messages from different writers */
1905                         if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1906                             (UNIXCB(skb).cred != siocb->scm->cred)) {
1907                                 skb_queue_head(&sk->sk_receive_queue, skb);
1908                                 break;
1909                         }
1910                 } else {
1911                         /* Copy credentials */
1912                         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1913                         check_creds = 1;
1914                 }
1915
1916                 /* Copy address just once */
1917                 if (sunaddr) {
1918                         unix_copy_addr(msg, skb->sk);
1919                         sunaddr = NULL;
1920                 }
1921
1922                 chunk = min_t(unsigned int, skb->len, size);
1923                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1924                         skb_queue_head(&sk->sk_receive_queue, skb);
1925                         if (copied == 0)
1926                                 copied = -EFAULT;
1927                         break;
1928                 }
1929                 copied += chunk;
1930                 size -= chunk;
1931
1932                 /* Mark read part of skb as used */
1933                 if (!(flags & MSG_PEEK)) {
1934                         skb_pull(skb, chunk);
1935
1936                         if (UNIXCB(skb).fp)
1937                                 unix_detach_fds(siocb->scm, skb);
1938
1939                         /* put the skb back if we didn't use it up.. */
1940                         if (skb->len) {
1941                                 skb_queue_head(&sk->sk_receive_queue, skb);
1942                                 break;
1943                         }
1944
1945                         consume_skb(skb);
1946
1947                         if (siocb->scm->fp)
1948                                 break;
1949                 } else {
1950                         /* It is questionable, see note in unix_dgram_recvmsg.
1951                          */
1952                         if (UNIXCB(skb).fp)
1953                                 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1954
1955                         /* put message back and return */
1956                         skb_queue_head(&sk->sk_receive_queue, skb);
1957                         break;
1958                 }
1959         } while (size);
1960
1961         mutex_unlock(&u->readlock);
1962         scm_recv(sock, msg, siocb->scm, flags);
1963 out:
1964         return copied ? : err;
1965 }
1966
1967 static int unix_shutdown(struct socket *sock, int mode)
1968 {
1969         struct sock *sk = sock->sk;
1970         struct sock *other;
1971
1972         mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1973
1974         if (mode) {
1975                 unix_state_lock(sk);
1976                 sk->sk_shutdown |= mode;
1977                 other = unix_peer(sk);
1978                 if (other)
1979                         sock_hold(other);
1980                 unix_state_unlock(sk);
1981                 sk->sk_state_change(sk);
1982
1983                 if (other &&
1984                         (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1985
1986                         int peer_mode = 0;
1987
1988                         if (mode&RCV_SHUTDOWN)
1989                                 peer_mode |= SEND_SHUTDOWN;
1990                         if (mode&SEND_SHUTDOWN)
1991                                 peer_mode |= RCV_SHUTDOWN;
1992                         unix_state_lock(other);
1993                         other->sk_shutdown |= peer_mode;
1994                         unix_state_unlock(other);
1995                         other->sk_state_change(other);
1996                         if (peer_mode == SHUTDOWN_MASK)
1997                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1998                         else if (peer_mode & RCV_SHUTDOWN)
1999                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2000                 }
2001                 if (other)
2002                         sock_put(other);
2003         }
2004         return 0;
2005 }
2006
2007 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2008 {
2009         struct sock *sk = sock->sk;
2010         long amount = 0;
2011         int err;
2012
2013         switch (cmd) {
2014         case SIOCOUTQ:
2015                 amount = sk_wmem_alloc_get(sk);
2016                 err = put_user(amount, (int __user *)arg);
2017                 break;
2018         case SIOCINQ:
2019                 {
2020                         struct sk_buff *skb;
2021
2022                         if (sk->sk_state == TCP_LISTEN) {
2023                                 err = -EINVAL;
2024                                 break;
2025                         }
2026
2027                         spin_lock(&sk->sk_receive_queue.lock);
2028                         if (sk->sk_type == SOCK_STREAM ||
2029                             sk->sk_type == SOCK_SEQPACKET) {
2030                                 skb_queue_walk(&sk->sk_receive_queue, skb)
2031                                         amount += skb->len;
2032                         } else {
2033                                 skb = skb_peek(&sk->sk_receive_queue);
2034                                 if (skb)
2035                                         amount = skb->len;
2036                         }
2037                         spin_unlock(&sk->sk_receive_queue.lock);
2038                         err = put_user(amount, (int __user *)arg);
2039                         break;
2040                 }
2041
2042         default:
2043                 err = -ENOIOCTLCMD;
2044                 break;
2045         }
2046         return err;
2047 }
2048
2049 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2050 {
2051         struct sock *sk = sock->sk;
2052         unsigned int mask;
2053
2054         sock_poll_wait(file, sk_sleep(sk), wait);
2055         mask = 0;
2056
2057         /* exceptional events? */
2058         if (sk->sk_err)
2059                 mask |= POLLERR;
2060         if (sk->sk_shutdown == SHUTDOWN_MASK)
2061                 mask |= POLLHUP;
2062         if (sk->sk_shutdown & RCV_SHUTDOWN)
2063                 mask |= POLLRDHUP;
2064
2065         /* readable? */
2066         if (!skb_queue_empty(&sk->sk_receive_queue) ||
2067             (sk->sk_shutdown & RCV_SHUTDOWN))
2068                 mask |= POLLIN | POLLRDNORM;
2069
2070         /* Connection-based need to check for termination and startup */
2071         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2072             sk->sk_state == TCP_CLOSE)
2073                 mask |= POLLHUP;
2074
2075         /*
2076          * we set writable also when the other side has shut down the
2077          * connection. This prevents stuck sockets.
2078          */
2079         if (unix_writable(sk))
2080                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2081
2082         return mask;
2083 }
2084
2085 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2086                                     poll_table *wait)
2087 {
2088         struct sock *sk = sock->sk, *other;
2089         unsigned int mask, writable;
2090
2091         sock_poll_wait(file, sk_sleep(sk), wait);
2092         mask = 0;
2093
2094         /* exceptional events? */
2095         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2096                 mask |= POLLERR;
2097         if (sk->sk_shutdown & RCV_SHUTDOWN)
2098                 mask |= POLLRDHUP;
2099         if (sk->sk_shutdown == SHUTDOWN_MASK)
2100                 mask |= POLLHUP;
2101
2102         /* readable? */
2103         if (!skb_queue_empty(&sk->sk_receive_queue) ||
2104             (sk->sk_shutdown & RCV_SHUTDOWN))
2105                 mask |= POLLIN | POLLRDNORM;
2106
2107         /* Connection-based need to check for termination and startup */
2108         if (sk->sk_type == SOCK_SEQPACKET) {
2109                 if (sk->sk_state == TCP_CLOSE)
2110                         mask |= POLLHUP;
2111                 /* connection hasn't started yet? */
2112                 if (sk->sk_state == TCP_SYN_SENT)
2113                         return mask;
2114         }
2115
2116         /* writable? */
2117         writable = unix_writable(sk);
2118         if (writable) {
2119                 other = unix_peer_get(sk);
2120                 if (other) {
2121                         if (unix_peer(other) != sk) {
2122                                 sock_poll_wait(file, &unix_sk(other)->peer_wait,
2123                                           wait);
2124                                 if (unix_recvq_full(other))
2125                                         writable = 0;
2126                         }
2127
2128                         sock_put(other);
2129                 }
2130         }
2131
2132         if (writable)
2133                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2134         else
2135                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2136
2137         return mask;
2138 }
2139
2140 #ifdef CONFIG_PROC_FS
2141 static struct sock *first_unix_socket(int *i)
2142 {
2143         for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2144                 if (!hlist_empty(&unix_socket_table[*i]))
2145                         return __sk_head(&unix_socket_table[*i]);
2146         }
2147         return NULL;
2148 }
2149
2150 static struct sock *next_unix_socket(int *i, struct sock *s)
2151 {
2152         struct sock *next = sk_next(s);
2153         /* More in this chain? */
2154         if (next)
2155                 return next;
2156         /* Look for next non-empty chain. */
2157         for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2158                 if (!hlist_empty(&unix_socket_table[*i]))
2159                         return __sk_head(&unix_socket_table[*i]);
2160         }
2161         return NULL;
2162 }
2163
2164 struct unix_iter_state {
2165         struct seq_net_private p;
2166         int i;
2167 };
2168
2169 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2170 {
2171         struct unix_iter_state *iter = seq->private;
2172         loff_t off = 0;
2173         struct sock *s;
2174
2175         for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2176                 if (sock_net(s) != seq_file_net(seq))
2177                         continue;
2178                 if (off == pos)
2179                         return s;
2180                 ++off;
2181         }
2182         return NULL;
2183 }
2184
2185 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2186         __acquires(unix_table_lock)
2187 {
2188         spin_lock(&unix_table_lock);
2189         return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2190 }
2191
2192 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2193 {
2194         struct unix_iter_state *iter = seq->private;
2195         struct sock *sk = v;
2196         ++*pos;
2197
2198         if (v == SEQ_START_TOKEN)
2199                 sk = first_unix_socket(&iter->i);
2200         else
2201                 sk = next_unix_socket(&iter->i, sk);
2202         while (sk && (sock_net(sk) != seq_file_net(seq)))
2203                 sk = next_unix_socket(&iter->i, sk);
2204         return sk;
2205 }
2206
2207 static void unix_seq_stop(struct seq_file *seq, void *v)
2208         __releases(unix_table_lock)
2209 {
2210         spin_unlock(&unix_table_lock);
2211 }
2212
2213 static int unix_seq_show(struct seq_file *seq, void *v)
2214 {
2215
2216         if (v == SEQ_START_TOKEN)
2217                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2218                          "Inode Path\n");
2219         else {
2220                 struct sock *s = v;
2221                 struct unix_sock *u = unix_sk(s);
2222                 unix_state_lock(s);
2223
2224                 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2225                         s,
2226                         atomic_read(&s->sk_refcnt),
2227                         0,
2228                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2229                         s->sk_type,
2230                         s->sk_socket ?
2231                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2232                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2233                         sock_i_ino(s));
2234
2235                 if (u->addr) {
2236                         int i, len;
2237                         seq_putc(seq, ' ');
2238
2239                         i = 0;
2240                         len = u->addr->len - sizeof(short);
2241                         if (!UNIX_ABSTRACT(s))
2242                                 len--;
2243                         else {
2244                                 seq_putc(seq, '@');
2245                                 i++;
2246                         }
2247                         for ( ; i < len; i++)
2248                                 seq_putc(seq, u->addr->name->sun_path[i]);
2249                 }
2250                 unix_state_unlock(s);
2251                 seq_putc(seq, '\n');
2252         }
2253
2254         return 0;
2255 }
2256
2257 static const struct seq_operations unix_seq_ops = {
2258         .start  = unix_seq_start,
2259         .next   = unix_seq_next,
2260         .stop   = unix_seq_stop,
2261         .show   = unix_seq_show,
2262 };
2263
2264 static int unix_seq_open(struct inode *inode, struct file *file)
2265 {
2266         return seq_open_net(inode, file, &unix_seq_ops,
2267                             sizeof(struct unix_iter_state));
2268 }
2269
2270 static const struct file_operations unix_seq_fops = {
2271         .owner          = THIS_MODULE,
2272         .open           = unix_seq_open,
2273         .read           = seq_read,
2274         .llseek         = seq_lseek,
2275         .release        = seq_release_net,
2276 };
2277
2278 #endif
2279
2280 static const struct net_proto_family unix_family_ops = {
2281         .family = PF_UNIX,
2282         .create = unix_create,
2283         .owner  = THIS_MODULE,
2284 };
2285
2286
2287 static int __net_init unix_net_init(struct net *net)
2288 {
2289         int error = -ENOMEM;
2290
2291         net->unx.sysctl_max_dgram_qlen = 10;
2292         if (unix_sysctl_register(net))
2293                 goto out;
2294
2295 #ifdef CONFIG_PROC_FS
2296         if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2297                 unix_sysctl_unregister(net);
2298                 goto out;
2299         }
2300 #endif
2301         error = 0;
2302 out:
2303         return error;
2304 }
2305
2306 static void __net_exit unix_net_exit(struct net *net)
2307 {
2308         unix_sysctl_unregister(net);
2309         proc_net_remove(net, "unix");
2310 }
2311
2312 static struct pernet_operations unix_net_ops = {
2313         .init = unix_net_init,
2314         .exit = unix_net_exit,
2315 };
2316
2317 static int __init af_unix_init(void)
2318 {
2319         int rc = -1;
2320         struct sk_buff *dummy_skb;
2321
2322         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2323
2324         rc = proto_register(&unix_proto, 1);
2325         if (rc != 0) {
2326                 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2327                        __func__);
2328                 goto out;
2329         }
2330
2331         sock_register(&unix_family_ops);
2332         register_pernet_subsys(&unix_net_ops);
2333 out:
2334         return rc;
2335 }
2336
2337 static void __exit af_unix_exit(void)
2338 {
2339         sock_unregister(PF_UNIX);
2340         proto_unregister(&unix_proto);
2341         unregister_pernet_subsys(&unix_net_ops);
2342 }
2343
2344 /* Earlier than device_initcall() so that other drivers invoking
2345    request_module() don't end up in a loop when modprobe tries
2346    to use a UNIX socket. But later than subsys_initcall() because
2347    we depend on stuff initialised there */
2348 fs_initcall(af_unix_init);
2349 module_exit(af_unix_exit);
2350
2351 MODULE_LICENSE("GPL");
2352 MODULE_ALIAS_NETPROTO(PF_UNIX);