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