SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/unix/af_unix.c

   1 /*
   2  * NET4:        Implementation of BSD Unix domain sockets.
   3  *
   4  * Authors:     Alan Cox, <alan@lxorguk.ukuu.org.uk>
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  *
  11  * Fixes:
  12  *              Linus Torvalds  :       Assorted bug cures.
  13  *              Niibe Yutaka    :       async I/O support.
  14  *              Carsten Paeth   :       PF_UNIX check, address fixes.
  15  *              Alan Cox        :       Limit size of allocated blocks.
  16  *              Alan Cox        :       Fixed the stupid socketpair bug.
  17  *              Alan Cox        :       BSD compatibility fine tuning.
  18  *              Alan Cox        :       Fixed a bug in connect when interrupted.
  19  *              Alan Cox        :       Sorted out a proper draft version of
  20  *                                      file descriptor passing hacked up from
  21  *                                      Mike Shaver's work.
  22  *              Marty Leisner   :       Fixes to fd passing
  23  *              Nick Nevin      :       recvmsg bugfix.
  24  *              Alan Cox        :       Started proper garbage collector
  25  *              Heiko EiBfeldt  :       Missing verify_area check
  26  *              Alan Cox        :       Started POSIXisms
  27  *              Andreas Schwab  :       Replace inode by dentry for proper
  28  *                                      reference counting
  29  *              Kirk Petersen   :       Made this a module
  30  *          Christoph Rohland   :       Elegant non-blocking accept/connect algorithm.
  31  *                                      Lots of bug fixes.
  32  *           Alexey Kuznetosv   :       Repaired (I hope) bugs introduces
  33  *                                      by above two patches.
  34  *           Andrea Arcangeli   :       If possible we block in connect(2)
  35  *                                      if the max backlog of the listen socket
  36  *                                      is been reached. This won't break
  37  *                                      old apps and it will avoid huge amount
  38  *                                      of socks hashed (this for unix_gc()
  39  *                                      performances reasons).
  40  *                                      Security fix that limits the max
  41  *                                      number of socks to 2*max_files and
  42  *                                      the number of skb queueable in the
  43  *                                      dgram receiver.
  44  *              Artur Skawina   :       Hash function optimizations
  45  *           Alexey Kuznetsov   :       Full scale SMP. Lot of bugs are introduced 8)
  46  *            Malcolm Beattie   :       Set peercred for socketpair
  47  *           Michal Ostrowski   :       Module initialization cleanup.
  48  *           Arnaldo C. Melo    :       Remove MOD_{INC,DEC}_USE_COUNT,
  49  *                                      the core infrastructure is doing that
  50  *                                      for all net proto families now (2.5.69+)
  51  *
  52  *
  53  * Known differences from reference BSD that was tested:
  54  *
  55  *      [TO FIX]
  56  *      ECONNREFUSED is not returned from one end of a connected() socket to the
  57  *              other the moment one end closes.
  58  *      fstat() doesn't return st_dev=0, and give the blksize as high water mark
  59  *              and a fake inode identifier (nor the BSD first socket fstat twice bug).
  60  *      [NOT TO FIX]
  61  *      accept() returns a path name even if the connecting socket has closed
  62  *              in the meantime (BSD loses the path and gives up).
  63  *      accept() returns 0 length path for an unbound connector. BSD returns 16
  64  *              and a null first byte in the path (but not for gethost/peername - BSD bug ??)
  65  *      socketpair(...SOCK_RAW..) doesn't panic the kernel.
  66  *      BSD af_unix apparently has connect forgetting to block properly.
  67  *              (need to check this with the POSIX spec in detail)
  68  *
  69  * Differences from 2.0.0-11-... (ANK)
  70  *      Bug fixes and improvements.
  71  *              - client shutdown killed server socket.
  72  *              - removed all useless cli/sti pairs.
  73  *
  74  *      Semantic changes/extensions.
  75  *              - generic control message passing.
  76  *              - SCM_CREDENTIALS control message.
  77  *              - "Abstract" (not FS based) socket bindings.
  78  *                Abstract names are sequences of bytes (not zero terminated)
  79  *                started by 0, so that this name space does not intersect
  80  *                with BSD names.
  81  */
  82
  83 #include <linux/module.h>
  84 #include <linux/kernel.h>
  85 #include <linux/signal.h>
  86 #include <linux/sched.h>
  87 #include <linux/errno.h>
  88 #include <linux/string.h>
  89 #include <linux/stat.h>
  90 #include <linux/dcache.h>
  91 #include <linux/namei.h>
  92 #include <linux/socket.h>
  93 #include <linux/un.h>
  94 #include <linux/fcntl.h>
  95 #include <linux/termios.h>
  96 #include <linux/sockios.h>
  97 #include <linux/net.h>
  98 #include <linux/in.h>
  99 #include <linux/fs.h>
 100 #include <linux/slab.h>
 101 #include <asm/uaccess.h>
 102 #include <linux/skbuff.h>
 103 #include <linux/netdevice.h>
 104 #include <net/net_namespace.h>
 105 #include <net/sock.h>
 106 #include <net/tcp_states.h>
 107 #include <net/af_unix.h>
 108 #include <linux/proc_fs.h>
 109 #include <linux/seq_file.h>
 110 #include <net/scm.h>
 111 #include <linux/init.h>
 112 #include <linux/poll.h>
 113 #include <linux/rtnetlink.h>
 114 #include <linux/mount.h>
 115 #include <net/checksum.h>
 116 #include <linux/security.h>
 117
 118 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
 119 static DEFINE_SPINLOCK(unix_table_lock);
 120 static atomic_t unix_nr_socks = ATOMIC_INIT(0);
 121
 122 #define unix_sockets_unbound    (&unix_socket_table[UNIX_HASH_SIZE])
 123
 124 #define UNIX_ABSTRACT(sk)       (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
 125
 126 #ifdef CONFIG_SECURITY_NETWORK
 127 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 128 {
 129         memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
 130 }
 131
 132 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 133 {
 134         scm->secid = *UNIXSID(skb);
 135 }
 136 #else
 137 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 138 { }
 139
 140 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 141 { }
 142 #endif /* CONFIG_SECURITY_NETWORK */
 143
 144 /*
 145  *  SMP locking strategy:
 146  *    hash table is protected with spinlock unix_table_lock
 147  *    each socket state is protected by separate rwlock.
 148  */
 149
 150 static inline unsigned unix_hash_fold(__wsum n)
 151 {
 152         unsigned hash = (__force unsigned)n;
 153         hash ^= hash>>16;
 154         hash ^= hash>>8;
 155         return hash&(UNIX_HASH_SIZE-1);
 156 }
 157
 158 #define unix_peer(sk) (unix_sk(sk)->peer)
 159
 160 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
 161 {
 162         return unix_peer(osk) == sk;
 163 }
 164
 165 static inline int unix_may_send(struct sock *sk, struct sock *osk)
 166 {
 167         return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
 168 }
 169
 170 static inline int unix_recvq_full(struct sock const *sk)
 171 {
 172         return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
 173 }
 174
 175 static struct sock *unix_peer_get(struct sock *s)
 176 {
 177         struct sock *peer;
 178
 179         unix_state_lock(s);
 180         peer = unix_peer(s);
 181         if (peer)
 182                 sock_hold(peer);
 183         unix_state_unlock(s);
 184         return peer;
 185 }
 186
 187 static inline void unix_release_addr(struct unix_address *addr)
 188 {
 189         if (atomic_dec_and_test(&addr->refcnt))
 190                 kfree(addr);
 191 }
 192
 193 /*
 194  *      Check unix socket name:
 195  *              - should be not zero length.
 196  *              - if started by not zero, should be NULL terminated (FS object)
 197  *              - if started by zero, it is abstract name.
 198  */
 199
 200 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
 201 {
 202         if (len <= sizeof(short) || len > sizeof(*sunaddr))
 203                 return -EINVAL;
 204         if (!sunaddr || sunaddr->sun_family != AF_UNIX)
 205                 return -EINVAL;
 206         if (sunaddr->sun_path[0]) {
 207                 /*
 208                  * This may look like an off by one error but it is a bit more
 209                  * subtle. 108 is the longest valid AF_UNIX path for a binding.
 210                  * sun_path[108] doesnt as such exist.  However in kernel space
 211                  * we are guaranteed that it is a valid memory location in our
 212                  * kernel address buffer.
 213                  */
 214                 ((char *)sunaddr)[len] = 0;
 215                 len = strlen(sunaddr->sun_path)+1+sizeof(short);
 216                 return len;
 217         }
 218
 219         *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
 220         return len;
 221 }
 222
 223 static void __unix_remove_socket(struct sock *sk)
 224 {
 225         sk_del_node_init(sk);
 226 }
 227
 228 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
 229 {
 230         WARN_ON(!sk_unhashed(sk));
 231         sk_add_node(sk, list);
 232 }
 233
 234 static inline void unix_remove_socket(struct sock *sk)
 235 {
 236         spin_lock(&unix_table_lock);
 237         __unix_remove_socket(sk);
 238         spin_unlock(&unix_table_lock);
 239 }
 240
 241 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
 242 {
 243         spin_lock(&unix_table_lock);
 244         __unix_insert_socket(list, sk);
 245         spin_unlock(&unix_table_lock);
 246 }
 247
 248 static struct sock *__unix_find_socket_byname(struct net *net,
 249                                               struct sockaddr_un *sunname,
 250                                               int len, int type, unsigned hash)
 251 {
 252         struct sock *s;
 253         struct hlist_node *node;
 254
 255         sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
 256                 struct unix_sock *u = unix_sk(s);
 257
 258                 if (!net_eq(sock_net(s), net))
 259                         continue;
 260
 261                 if (u->addr->len == len &&
 262                     !memcmp(u->addr->name, sunname, len))
 263                         goto found;
 264         }
 265         s = NULL;
 266 found:
 267         return s;
 268 }
 269
 270 static inline struct sock *unix_find_socket_byname(struct net *net,
 271                                                    struct sockaddr_un *sunname,
 272                                                    int len, int type,
 273                                                    unsigned hash)
 274 {
 275         struct sock *s;
 276
 277         spin_lock(&unix_table_lock);
 278         s = __unix_find_socket_byname(net, sunname, len, type, hash);
 279         if (s)
 280                 sock_hold(s);
 281         spin_unlock(&unix_table_lock);
 282         return s;
 283 }
 284
 285 static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
 286 {
 287         struct sock *s;
 288         struct hlist_node *node;
 289
 290         spin_lock(&unix_table_lock);
 291         sk_for_each(s, node,
 292                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
 293                 struct dentry *dentry = unix_sk(s)->dentry;
 294
 295                 if (!net_eq(sock_net(s), net))
 296                         continue;
 297
 298                 if (dentry && dentry->d_inode == i) {
 299                         sock_hold(s);
 300                         goto found;
 301                 }
 302         }
 303         s = NULL;
 304 found:
 305         spin_unlock(&unix_table_lock);
 306         return s;
 307 }
 308
 309 static inline int unix_writable(struct sock *sk)
 310 {
 311         return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
 312 }
 313
 314 static void unix_write_space(struct sock *sk)
 315 {
 316         read_lock(&sk->sk_callback_lock);
 317         if (unix_writable(sk)) {
 318                 if (sk_has_sleeper(sk))
 319                         wake_up_interruptible_sync(sk->sk_sleep);
 320                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 321         }
 322         read_unlock(&sk->sk_callback_lock);
 323 }
 324
 325 /* When dgram socket disconnects (or changes its peer), we clear its receive
 326  * queue of packets arrived from previous peer. First, it allows to do
 327  * flow control based only on wmem_alloc; second, sk connected to peer
 328  * may receive messages only from that peer. */
 329 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
 330 {
 331         if (!skb_queue_empty(&sk->sk_receive_queue)) {
 332                 skb_queue_purge(&sk->sk_receive_queue);
 333                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
 334
 335                 /* If one link of bidirectional dgram pipe is disconnected,
 336                  * we signal error. Messages are lost. Do not make this,
 337                  * when peer was not connected to us.
 338                  */
 339                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
 340                         other->sk_err = ECONNRESET;
 341                         other->sk_error_report(other);
 342                 }
 343         }
 344 }
 345
 346 static void unix_sock_destructor(struct sock *sk)
 347 {
 348         struct unix_sock *u = unix_sk(sk);
 349
 350         skb_queue_purge(&sk->sk_receive_queue);
 351
 352         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
 353         WARN_ON(!sk_unhashed(sk));
 354         WARN_ON(sk->sk_socket);
 355         if (!sock_flag(sk, SOCK_DEAD)) {
 356                 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
 357                 return;
 358         }
 359
 360         if (u->addr)
 361                 unix_release_addr(u->addr);
 362
 363         atomic_dec(&unix_nr_socks);
 364         local_bh_disable();
 365         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 366         local_bh_enable();
 367 #ifdef UNIX_REFCNT_DEBUG
 368         printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk,
 369                 atomic_read(&unix_nr_socks));
 370 #endif
 371 }
 372
 373 static int unix_release_sock(struct sock *sk, int embrion)
 374 {
 375         struct unix_sock *u = unix_sk(sk);
 376         struct dentry *dentry;
 377         struct vfsmount *mnt;
 378         struct sock *skpair;
 379         struct sk_buff *skb;
 380         int state;
 381
 382         unix_remove_socket(sk);
 383
 384         /* Clear state */
 385         unix_state_lock(sk);
 386         sock_orphan(sk);
 387         sk->sk_shutdown = SHUTDOWN_MASK;
 388         dentry       = u->dentry;
 389         u->dentry    = NULL;
 390         mnt          = u->mnt;
 391         u->mnt       = NULL;
 392         state = sk->sk_state;
 393         sk->sk_state = TCP_CLOSE;
 394         unix_state_unlock(sk);
 395
 396         wake_up_interruptible_all(&u->peer_wait);
 397
 398         skpair = unix_peer(sk);
 399
 400         if (skpair != NULL) {
 401                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
 402                         unix_state_lock(skpair);
 403                         /* No more writes */
 404                         skpair->sk_shutdown = SHUTDOWN_MASK;
 405                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 406                                 skpair->sk_err = ECONNRESET;
 407                         unix_state_unlock(skpair);
 408                         skpair->sk_state_change(skpair);
 409                         read_lock(&skpair->sk_callback_lock);
 410                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
 411                         read_unlock(&skpair->sk_callback_lock);
 412                 }
 413                 sock_put(skpair); /* It may now die */
 414                 unix_peer(sk) = NULL;
 415         }
 416
 417         /* Try to flush out this socket. Throw out buffers at least */
 418
 419         while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 420                 if (state == TCP_LISTEN)
 421                         unix_release_sock(skb->sk, 1);
 422                 /* passed fds are erased in the kfree_skb hook        */
 423                 kfree_skb(skb);
 424         }
 425
 426         if (dentry) {
 427                 dput(dentry);
 428                 mntput(mnt);
 429         }
 430
 431         sock_put(sk);
 432
 433         /* ---- Socket is dead now and most probably destroyed ---- */
 434
 435         /*
 436          * Fixme: BSD difference: In BSD all sockets connected to use get
 437          *        ECONNRESET and we die on the spot. In Linux we behave
 438          *        like files and pipes do and wait for the last
 439          *        dereference.
 440          *
 441          * Can't we simply set sock->err?
 442          *
 443          *        What the above comment does talk about? --ANK(980817)
 444          */
 445
 446         if (unix_tot_inflight)
 447                 unix_gc();              /* Garbage collect fds */
 448
 449         return 0;
 450 }
 451
 452 static int unix_listen(struct socket *sock, int backlog)
 453 {
 454         int err;
 455         struct sock *sk = sock->sk;
 456         struct unix_sock *u = unix_sk(sk);
 457
 458         err = -EOPNOTSUPP;
 459         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
 460                 goto out;       /* Only stream/seqpacket sockets accept */
 461         err = -EINVAL;
 462         if (!u->addr)
 463                 goto out;       /* No listens on an unbound socket */
 464         unix_state_lock(sk);
 465         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
 466                 goto out_unlock;
 467         if (backlog > sk->sk_max_ack_backlog)
 468                 wake_up_interruptible_all(&u->peer_wait);
 469         sk->sk_max_ack_backlog  = backlog;
 470         sk->sk_state            = TCP_LISTEN;
 471         /* set credentials so connect can copy them */
 472         sk->sk_peercred.pid     = task_tgid_vnr(current);
 473         current_euid_egid(&sk->sk_peercred.uid, &sk->sk_peercred.gid);
 474         err = 0;
 475
 476 out_unlock:
 477         unix_state_unlock(sk);
 478 out:
 479         return err;
 480 }
 481
 482 static int unix_release(struct socket *);
 483 static int unix_bind(struct socket *, struct sockaddr *, int);
 484 static int unix_stream_connect(struct socket *, struct sockaddr *,
 485                                int addr_len, int flags);
 486 static int unix_socketpair(struct socket *, struct socket *);
 487 static int unix_accept(struct socket *, struct socket *, int);
 488 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
 489 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
 490 static unsigned int unix_dgram_poll(struct file *, struct socket *,
 491                                     poll_table *);
 492 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
 493 static int unix_shutdown(struct socket *, int);
 494 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
 495                                struct msghdr *, size_t);
 496 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
 497                                struct msghdr *, size_t, int);
 498 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
 499                               struct msghdr *, size_t);
 500 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
 501                               struct msghdr *, size_t, int);
 502 static int unix_dgram_connect(struct socket *, struct sockaddr *,
 503                               int, int);
 504 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
 505                                   struct msghdr *, size_t);
 506
 507 static const struct proto_ops unix_stream_ops = {
 508         .family =       PF_UNIX,
 509         .owner =        THIS_MODULE,
 510         .release =      unix_release,
 511         .bind =         unix_bind,
 512         .connect =      unix_stream_connect,
 513         .socketpair =   unix_socketpair,
 514         .accept =       unix_accept,
 515         .getname =      unix_getname,
 516         .poll =         unix_poll,
 517         .ioctl =        unix_ioctl,
 518         .listen =       unix_listen,
 519         .shutdown =     unix_shutdown,
 520         .setsockopt =   sock_no_setsockopt,
 521         .getsockopt =   sock_no_getsockopt,
 522         .sendmsg =      unix_stream_sendmsg,
 523         .recvmsg =      unix_stream_recvmsg,
 524         .mmap =         sock_no_mmap,
 525         .sendpage =     sock_no_sendpage,
 526 };
 527
 528 static const struct proto_ops unix_dgram_ops = {
 529         .family =       PF_UNIX,
 530         .owner =        THIS_MODULE,
 531         .release =      unix_release,
 532         .bind =         unix_bind,
 533         .connect =      unix_dgram_connect,
 534         .socketpair =   unix_socketpair,
 535         .accept =       sock_no_accept,
 536         .getname =      unix_getname,
 537         .poll =         unix_dgram_poll,
 538         .ioctl =        unix_ioctl,
 539         .listen =       sock_no_listen,
 540         .shutdown =     unix_shutdown,
 541         .setsockopt =   sock_no_setsockopt,
 542         .getsockopt =   sock_no_getsockopt,
 543         .sendmsg =      unix_dgram_sendmsg,
 544         .recvmsg =      unix_dgram_recvmsg,
 545         .mmap =         sock_no_mmap,
 546         .sendpage =     sock_no_sendpage,
 547 };
 548
 549 static const struct proto_ops unix_seqpacket_ops = {
 550         .family =       PF_UNIX,
 551         .owner =        THIS_MODULE,
 552         .release =      unix_release,
 553         .bind =         unix_bind,
 554         .connect =      unix_stream_connect,
 555         .socketpair =   unix_socketpair,
 556         .accept =       unix_accept,
 557         .getname =      unix_getname,
 558         .poll =         unix_dgram_poll,
 559         .ioctl =        unix_ioctl,
 560         .listen =       unix_listen,
 561         .shutdown =     unix_shutdown,
 562         .setsockopt =   sock_no_setsockopt,
 563         .getsockopt =   sock_no_getsockopt,
 564         .sendmsg =      unix_seqpacket_sendmsg,
 565         .recvmsg =      unix_dgram_recvmsg,
 566         .mmap =         sock_no_mmap,
 567         .sendpage =     sock_no_sendpage,
 568 };
 569
 570 static struct proto unix_proto = {
 571         .name                   = "UNIX",
 572         .owner                  = THIS_MODULE,
 573         .obj_size               = sizeof(struct unix_sock),
 574 };
 575
 576 /*
 577  * AF_UNIX sockets do not interact with hardware, hence they
 578  * dont trigger interrupts - so it's safe for them to have
 579  * bh-unsafe locking for their sk_receive_queue.lock. Split off
 580  * this special lock-class by reinitializing the spinlock key:
 581  */
 582 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
 583
 584 static struct sock *unix_create1(struct net *net, struct socket *sock)
 585 {
 586         struct sock *sk = NULL;
 587         struct unix_sock *u;
 588
 589         atomic_inc(&unix_nr_socks);
 590         if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
 591                 goto out;
 592
 593         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
 594         if (!sk)
 595                 goto out;
 596
 597         sock_init_data(sock, sk);
 598         lockdep_set_class(&sk->sk_receive_queue.lock,
 599                                 &af_unix_sk_receive_queue_lock_key);
 600
 601         sk->sk_write_space      = unix_write_space;
 602         sk->sk_max_ack_backlog  = net->unx.sysctl_max_dgram_qlen;
 603         sk->sk_destruct         = unix_sock_destructor;
 604         u         = unix_sk(sk);
 605         u->dentry = NULL;
 606         u->mnt    = NULL;
 607         spin_lock_init(&u->lock);
 608         atomic_long_set(&u->inflight, 0);
 609         INIT_LIST_HEAD(&u->link);
 610         mutex_init(&u->readlock); /* single task reading lock */
 611         init_waitqueue_head(&u->peer_wait);
 612         unix_insert_socket(unix_sockets_unbound, sk);
 613 out:
 614         if (sk == NULL)
 615                 atomic_dec(&unix_nr_socks);
 616         else {
 617                 local_bh_disable();
 618                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 619                 local_bh_enable();
 620         }
 621         return sk;
 622 }
 623
 624 static int unix_create(struct net *net, struct socket *sock, int protocol)
 625 {
 626         if (protocol && protocol != PF_UNIX)
 627                 return -EPROTONOSUPPORT;
 628
 629         sock->state = SS_UNCONNECTED;
 630
 631         switch (sock->type) {
 632         case SOCK_STREAM:
 633                 sock->ops = &unix_stream_ops;
 634                 break;
 635                 /*
 636                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
 637                  *      nothing uses it.
 638                  */
 639         case SOCK_RAW:
 640                 sock->type = SOCK_DGRAM;
 641         case SOCK_DGRAM:
 642                 sock->ops = &unix_dgram_ops;
 643                 break;
 644         case SOCK_SEQPACKET:
 645                 sock->ops = &unix_seqpacket_ops;
 646                 break;
 647         default:
 648                 return -ESOCKTNOSUPPORT;
 649         }
 650
 651         return unix_create1(net, sock) ? 0 : -ENOMEM;
 652 }
 653
 654 static int unix_release(struct socket *sock)
 655 {
 656         struct sock *sk = sock->sk;
 657
 658         if (!sk)
 659                 return 0;
 660
 661         sock->sk = NULL;
 662
 663         return unix_release_sock(sk, 0);
 664 }
 665
 666 static int unix_autobind(struct socket *sock)
 667 {
 668         struct sock *sk = sock->sk;
 669         struct net *net = sock_net(sk);
 670         struct unix_sock *u = unix_sk(sk);
 671         static u32 ordernum = 1;
 672         struct unix_address *addr;
 673         int err;
 674
 675         mutex_lock(&u->readlock);
 676
 677         err = 0;
 678         if (u->addr)
 679                 goto out;
 680
 681         err = -ENOMEM;
 682         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
 683         if (!addr)
 684                 goto out;
 685
 686         addr->name->sun_family = AF_UNIX;
 687         atomic_set(&addr->refcnt, 1);
 688
 689 retry:
 690         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
 691         addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
 692
 693         spin_lock(&unix_table_lock);
 694         ordernum = (ordernum+1)&0xFFFFF;
 695
 696         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
 697                                       addr->hash)) {
 698                 spin_unlock(&unix_table_lock);
 699                 /* Sanity yield. It is unusual case, but yet... */
 700                 if (!(ordernum&0xFF))
 701                         yield();
 702                 goto retry;
 703         }
 704         addr->hash ^= sk->sk_type;
 705
 706         __unix_remove_socket(sk);
 707         u->addr = addr;
 708         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
 709         spin_unlock(&unix_table_lock);
 710         err = 0;
 711
 712 out:    mutex_unlock(&u->readlock);
 713         return err;
 714 }
 715
 716 static struct sock *unix_find_other(struct net *net,
 717                                     struct sockaddr_un *sunname, int len,
 718                                     int type, unsigned hash, int *error)
 719 {
 720         struct sock *u;
 721         struct path path;
 722         int err = 0;
 723
 724         if (sunname->sun_path[0]) {
 725                 struct inode *inode;
 726                 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
 727                 if (err)
 728                         goto fail;
 729                 inode = path.dentry->d_inode;
 730                 err = inode_permission(inode, MAY_WRITE);
 731                 if (err)
 732                         goto put_fail;
 733
 734                 err = -ECONNREFUSED;
 735                 if (!S_ISSOCK(inode->i_mode))
 736                         goto put_fail;
 737                 u = unix_find_socket_byinode(net, inode);
 738                 if (!u)
 739                         goto put_fail;
 740
 741                 if (u->sk_type == type)
 742                         touch_atime(path.mnt, path.dentry);
 743
 744                 path_put(&path);
 745
 746                 err = -EPROTOTYPE;
 747                 if (u->sk_type != type) {
 748                         sock_put(u);
 749                         goto fail;
 750                 }
 751         } else {
 752                 err = -ECONNREFUSED;
 753                 u = unix_find_socket_byname(net, sunname, len, type, hash);
 754                 if (u) {
 755                         struct dentry *dentry;
 756                         dentry = unix_sk(u)->dentry;
 757                         if (dentry)
 758                                 touch_atime(unix_sk(u)->mnt, dentry);
 759                 } else
 760                         goto fail;
 761         }
 762         return u;
 763
 764 put_fail:
 765         path_put(&path);
 766 fail:
 767         *error = err;
 768         return NULL;
 769 }
 770
 771
 772 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 773 {
 774         struct sock *sk = sock->sk;
 775         struct net *net = sock_net(sk);
 776         struct unix_sock *u = unix_sk(sk);
 777         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
 778         struct dentry *dentry = NULL;
 779         struct nameidata nd;
 780         int err;
 781         unsigned hash;
 782         struct unix_address *addr;
 783         struct hlist_head *list;
 784
 785         err = -EINVAL;
 786         if (sunaddr->sun_family != AF_UNIX)
 787                 goto out;
 788
 789         if (addr_len == sizeof(short)) {
 790                 err = unix_autobind(sock);
 791                 goto out;
 792         }
 793
 794         err = unix_mkname(sunaddr, addr_len, &hash);
 795         if (err < 0)
 796                 goto out;
 797         addr_len = err;
 798
 799         mutex_lock(&u->readlock);
 800
 801         err = -EINVAL;
 802         if (u->addr)
 803                 goto out_up;
 804
 805         err = -ENOMEM;
 806         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
 807         if (!addr)
 808                 goto out_up;
 809
 810         memcpy(addr->name, sunaddr, addr_len);
 811         addr->len = addr_len;
 812         addr->hash = hash ^ sk->sk_type;
 813         atomic_set(&addr->refcnt, 1);
 814
 815         if (sunaddr->sun_path[0]) {
 816                 unsigned int mode;
 817                 err = 0;
 818                 /*
 819                  * Get the parent directory, calculate the hash for last
 820                  * component.
 821                  */
 822                 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
 823                 if (err)
 824                         goto out_mknod_parent;
 825
 826                 dentry = lookup_create(&nd, 0);
 827                 err = PTR_ERR(dentry);
 828                 if (IS_ERR(dentry))
 829                         goto out_mknod_unlock;
 830
 831                 /*
 832                  * All right, let's create it.
 833                  */
 834                 mode = S_IFSOCK |
 835                        (SOCK_INODE(sock)->i_mode & ~current_umask());
 836                 err = mnt_want_write(nd.path.mnt);
 837                 if (err)
 838                         goto out_mknod_dput;
 839                 err = security_path_mknod(&nd.path, dentry, mode, 0);
 840                 if (err)
 841                         goto out_mknod_drop_write;
 842                 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
 843 out_mknod_drop_write:
 844                 mnt_drop_write(nd.path.mnt);
 845                 if (err)
 846                         goto out_mknod_dput;
 847                 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 848                 dput(nd.path.dentry);
 849                 nd.path.dentry = dentry;
 850
 851                 addr->hash = UNIX_HASH_SIZE;
 852         }
 853
 854         spin_lock(&unix_table_lock);
 855
 856         if (!sunaddr->sun_path[0]) {
 857                 err = -EADDRINUSE;
 858                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
 859                                               sk->sk_type, hash)) {
 860                         unix_release_addr(addr);
 861                         goto out_unlock;
 862                 }
 863
 864                 list = &unix_socket_table[addr->hash];
 865         } else {
 866                 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
 867                 u->dentry = nd.path.dentry;
 868                 u->mnt    = nd.path.mnt;
 869         }
 870
 871         err = 0;
 872         __unix_remove_socket(sk);
 873         u->addr = addr;
 874         __unix_insert_socket(list, sk);
 875
 876 out_unlock:
 877         spin_unlock(&unix_table_lock);
 878 out_up:
 879         mutex_unlock(&u->readlock);
 880 out:
 881         return err;
 882
 883 out_mknod_dput:
 884         dput(dentry);
 885 out_mknod_unlock:
 886         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 887         path_put(&nd.path);
 888 out_mknod_parent:
 889         if (err == -EEXIST)
 890                 err = -EADDRINUSE;
 891         unix_release_addr(addr);
 892         goto out_up;
 893 }
 894
 895 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
 896 {
 897         if (unlikely(sk1 == sk2) || !sk2) {
 898                 unix_state_lock(sk1);
 899                 return;
 900         }
 901         if (sk1 < sk2) {
 902                 unix_state_lock(sk1);
 903                 unix_state_lock_nested(sk2);
 904         } else {
 905                 unix_state_lock(sk2);
 906                 unix_state_lock_nested(sk1);
 907         }
 908 }
 909
 910 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
 911 {
 912         if (unlikely(sk1 == sk2) || !sk2) {
 913                 unix_state_unlock(sk1);
 914                 return;
 915         }
 916         unix_state_unlock(sk1);
 917         unix_state_unlock(sk2);
 918 }
 919
 920 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 921                               int alen, int flags)
 922 {
 923         struct sock *sk = sock->sk;
 924         struct net *net = sock_net(sk);
 925         struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
 926         struct sock *other;
 927         unsigned hash;
 928         int err;
 929
 930         if (addr->sa_family != AF_UNSPEC) {
 931                 err = unix_mkname(sunaddr, alen, &hash);
 932                 if (err < 0)
 933                         goto out;
 934                 alen = err;
 935
 936                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
 937                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
 938                         goto out;
 939
 940 restart:
 941                 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
 942                 if (!other)
 943                         goto out;
 944
 945                 unix_state_double_lock(sk, other);
 946
 947                 /* Apparently VFS overslept socket death. Retry. */
 948                 if (sock_flag(other, SOCK_DEAD)) {
 949                         unix_state_double_unlock(sk, other);
 950                         sock_put(other);
 951                         goto restart;
 952                 }
 953
 954                 err = -EPERM;
 955                 if (!unix_may_send(sk, other))
 956                         goto out_unlock;
 957
 958                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
 959                 if (err)
 960                         goto out_unlock;
 961
 962         } else {
 963                 /*
 964                  *      1003.1g breaking connected state with AF_UNSPEC
 965                  */
 966                 other = NULL;
 967                 unix_state_double_lock(sk, other);
 968         }
 969
 970         /*
 971          * If it was connected, reconnect.
 972          */
 973         if (unix_peer(sk)) {
 974                 struct sock *old_peer = unix_peer(sk);
 975                 unix_peer(sk) = other;
 976                 unix_state_double_unlock(sk, other);
 977
 978                 if (other != old_peer)
 979                         unix_dgram_disconnected(sk, old_peer);
 980                 sock_put(old_peer);
 981         } else {
 982                 unix_peer(sk) = other;
 983                 unix_state_double_unlock(sk, other);
 984         }
 985         return 0;
 986
 987 out_unlock:
 988         unix_state_double_unlock(sk, other);
 989         sock_put(other);
 990 out:
 991         return err;
 992 }
 993
 994 static long unix_wait_for_peer(struct sock *other, long timeo)
 995 {
 996         struct unix_sock *u = unix_sk(other);
 997         int sched;
 998         DEFINE_WAIT(wait);
 999
1000         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1001
1002         sched = !sock_flag(other, SOCK_DEAD) &&
1003                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1004                 unix_recvq_full(other);
1005
1006         unix_state_unlock(other);
1007
1008         if (sched)
1009                 timeo = schedule_timeout(timeo);
1010
1011         finish_wait(&u->peer_wait, &wait);
1012         return timeo;
1013 }
1014
1015 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1016                                int addr_len, int flags)
1017 {
1018         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1019         struct sock *sk = sock->sk;
1020         struct net *net = sock_net(sk);
1021         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1022         struct sock *newsk = NULL;
1023         struct sock *other = NULL;
1024         struct sk_buff *skb = NULL;
1025         unsigned hash;
1026         int st;
1027         int err;
1028         long timeo;
1029
1030         err = unix_mkname(sunaddr, addr_len, &hash);
1031         if (err < 0)
1032                 goto out;
1033         addr_len = err;
1034
1035         if (test_bit(SOCK_PASSCRED, &sock->flags)
1036                 && !u->addr && (err = unix_autobind(sock)) != 0)
1037                 goto out;
1038
1039         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1040
1041         /* First of all allocate resources.
1042            If we will make it after state is locked,
1043            we will have to recheck all again in any case.
1044          */
1045
1046         err = -ENOMEM;
1047
1048         /* create new sock for complete connection */
1049         newsk = unix_create1(sock_net(sk), NULL);
1050         if (newsk == NULL)
1051                 goto out;
1052
1053         /* Allocate skb for sending to listening sock */
1054         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1055         if (skb == NULL)
1056                 goto out;
1057
1058 restart:
1059         /*  Find listening sock. */
1060         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1061         if (!other)
1062                 goto out;
1063
1064         /* Latch state of peer */
1065         unix_state_lock(other);
1066
1067         /* Apparently VFS overslept socket death. Retry. */
1068         if (sock_flag(other, SOCK_DEAD)) {
1069                 unix_state_unlock(other);
1070                 sock_put(other);
1071                 goto restart;
1072         }
1073
1074         err = -ECONNREFUSED;
1075         if (other->sk_state != TCP_LISTEN)
1076                 goto out_unlock;
1077
1078         if (unix_recvq_full(other)) {
1079                 err = -EAGAIN;
1080                 if (!timeo)
1081                         goto out_unlock;
1082
1083                 timeo = unix_wait_for_peer(other, timeo);
1084
1085                 err = sock_intr_errno(timeo);
1086                 if (signal_pending(current))
1087                         goto out;
1088                 sock_put(other);
1089                 goto restart;
1090         }
1091
1092         /* Latch our state.
1093
1094            It is tricky place. We need to grab write lock and cannot
1095            drop lock on peer. It is dangerous because deadlock is
1096            possible. Connect to self case and simultaneous
1097            attempt to connect are eliminated by checking socket
1098            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1099            check this before attempt to grab lock.
1100
1101            Well, and we have to recheck the state after socket locked.
1102          */
1103         st = sk->sk_state;
1104
1105         switch (st) {
1106         case TCP_CLOSE:
1107                 /* This is ok... continue with connect */
1108                 break;
1109         case TCP_ESTABLISHED:
1110                 /* Socket is already connected */
1111                 err = -EISCONN;
1112                 goto out_unlock;
1113         default:
1114                 err = -EINVAL;
1115                 goto out_unlock;
1116         }
1117
1118         unix_state_lock_nested(sk);
1119
1120         if (sk->sk_state != st) {
1121                 unix_state_unlock(sk);
1122                 unix_state_unlock(other);
1123                 sock_put(other);
1124                 goto restart;
1125         }
1126
1127         err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1128         if (err) {
1129                 unix_state_unlock(sk);
1130                 goto out_unlock;
1131         }
1132
1133         /* The way is open! Fastly set all the necessary fields... */
1134
1135         sock_hold(sk);
1136         unix_peer(newsk)        = sk;
1137         newsk->sk_state         = TCP_ESTABLISHED;
1138         newsk->sk_type          = sk->sk_type;
1139         newsk->sk_peercred.pid  = task_tgid_vnr(current);
1140         current_euid_egid(&newsk->sk_peercred.uid, &newsk->sk_peercred.gid);
1141         newu = unix_sk(newsk);
1142         newsk->sk_sleep         = &newu->peer_wait;
1143         otheru = unix_sk(other);
1144
1145         /* copy address information from listening to new sock*/
1146         if (otheru->addr) {
1147                 atomic_inc(&otheru->addr->refcnt);
1148                 newu->addr = otheru->addr;
1149         }
1150         if (otheru->dentry) {
1151                 newu->dentry    = dget(otheru->dentry);
1152                 newu->mnt       = mntget(otheru->mnt);
1153         }
1154
1155         /* Set credentials */
1156         sk->sk_peercred = other->sk_peercred;
1157
1158         sock->state     = SS_CONNECTED;
1159         sk->sk_state    = TCP_ESTABLISHED;
1160         sock_hold(newsk);
1161
1162         smp_mb__after_atomic_inc();     /* sock_hold() does an atomic_inc() */
1163         unix_peer(sk)   = newsk;
1164
1165         unix_state_unlock(sk);
1166
1167         /* take ten and and send info to listening sock */
1168         spin_lock(&other->sk_receive_queue.lock);
1169         __skb_queue_tail(&other->sk_receive_queue, skb);
1170         spin_unlock(&other->sk_receive_queue.lock);
1171         unix_state_unlock(other);
1172         other->sk_data_ready(other, 0);
1173         sock_put(other);
1174         return 0;
1175
1176 out_unlock:
1177         if (other)
1178                 unix_state_unlock(other);
1179
1180 out:
1181         kfree_skb(skb);
1182         if (newsk)
1183                 unix_release_sock(newsk, 0);
1184         if (other)
1185                 sock_put(other);
1186         return err;
1187 }
1188
1189 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1190 {
1191         struct sock *ska = socka->sk, *skb = sockb->sk;
1192
1193         /* Join our sockets back to back */
1194         sock_hold(ska);
1195         sock_hold(skb);
1196         unix_peer(ska) = skb;
1197         unix_peer(skb) = ska;
1198         ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
1199         current_euid_egid(&skb->sk_peercred.uid, &skb->sk_peercred.gid);
1200         ska->sk_peercred.uid = skb->sk_peercred.uid;
1201         ska->sk_peercred.gid = skb->sk_peercred.gid;
1202
1203         if (ska->sk_type != SOCK_DGRAM) {
1204                 ska->sk_state = TCP_ESTABLISHED;
1205                 skb->sk_state = TCP_ESTABLISHED;
1206                 socka->state  = SS_CONNECTED;
1207                 sockb->state  = SS_CONNECTED;
1208         }
1209         return 0;
1210 }
1211
1212 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1213 {
1214         struct sock *sk = sock->sk;
1215         struct sock *tsk;
1216         struct sk_buff *skb;
1217         int err;
1218
1219         err = -EOPNOTSUPP;
1220         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1221                 goto out;
1222
1223         err = -EINVAL;
1224         if (sk->sk_state != TCP_LISTEN)
1225                 goto out;
1226
1227         /* If socket state is TCP_LISTEN it cannot change (for now...),
1228          * so that no locks are necessary.
1229          */
1230
1231         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1232         if (!skb) {
1233                 /* This means receive shutdown. */
1234                 if (err == 0)
1235                         err = -EINVAL;
1236                 goto out;
1237         }
1238
1239         tsk = skb->sk;
1240         skb_free_datagram(sk, skb);
1241         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1242
1243         /* attach accepted sock to socket */
1244         unix_state_lock(tsk);
1245         newsock->state = SS_CONNECTED;
1246         sock_graft(tsk, newsock);
1247         unix_state_unlock(tsk);
1248         return 0;
1249
1250 out:
1251         return err;
1252 }
1253
1254
1255 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1256 {
1257         struct sock *sk = sock->sk;
1258         struct unix_sock *u;
1259         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1260         int err = 0;
1261
1262         if (peer) {
1263                 sk = unix_peer_get(sk);
1264
1265                 err = -ENOTCONN;
1266                 if (!sk)
1267                         goto out;
1268                 err = 0;
1269         } else {
1270                 sock_hold(sk);
1271         }
1272
1273         u = unix_sk(sk);
1274         unix_state_lock(sk);
1275         if (!u->addr) {
1276                 sunaddr->sun_family = AF_UNIX;
1277                 sunaddr->sun_path[0] = 0;
1278                 *uaddr_len = sizeof(short);
1279         } else {
1280                 struct unix_address *addr = u->addr;
1281
1282                 *uaddr_len = addr->len;
1283                 memcpy(sunaddr, addr->name, *uaddr_len);
1284         }
1285         unix_state_unlock(sk);
1286         sock_put(sk);
1287 out:
1288         return err;
1289 }
1290
1291 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1292 {
1293         int i;
1294
1295         scm->fp = UNIXCB(skb).fp;
1296         skb->destructor = sock_wfree;
1297         UNIXCB(skb).fp = NULL;
1298
1299         for (i = scm->fp->count-1; i >= 0; i--)
1300                 unix_notinflight(scm->fp->fp[i]);
1301 }
1302
1303 static void unix_destruct_fds(struct sk_buff *skb)
1304 {
1305         struct scm_cookie scm;
1306         memset(&scm, 0, sizeof(scm));
1307         unix_detach_fds(&scm, skb);
1308
1309         /* Alas, it calls VFS */
1310         /* So fscking what? fput() had been SMP-safe since the last Summer */
1311         scm_destroy(&scm);
1312         sock_wfree(skb);
1313 }
1314
1315 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1316 {
1317         int i;
1318
1319         /*
1320          * Need to duplicate file references for the sake of garbage
1321          * collection.  Otherwise a socket in the fps might become a
1322          * candidate for GC while the skb is not yet queued.
1323          */
1324         UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1325         if (!UNIXCB(skb).fp)
1326                 return -ENOMEM;
1327
1328         for (i = scm->fp->count-1; i >= 0; i--)
1329                 unix_inflight(scm->fp->fp[i]);
1330         skb->destructor = unix_destruct_fds;
1331         return 0;
1332 }
1333
1334 /*
1335  *      Send AF_UNIX data.
1336  */
1337
1338 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1339                               struct msghdr *msg, size_t len)
1340 {
1341         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1342         struct sock *sk = sock->sk;
1343         struct net *net = sock_net(sk);
1344         struct unix_sock *u = unix_sk(sk);
1345         struct sockaddr_un *sunaddr = msg->msg_name;
1346         struct sock *other = NULL;
1347         int namelen = 0; /* fake GCC */
1348         int err;
1349         unsigned hash;
1350         struct sk_buff *skb;
1351         long timeo;
1352         struct scm_cookie tmp_scm;
1353
1354         if (NULL == siocb->scm)
1355                 siocb->scm = &tmp_scm;
1356         wait_for_unix_gc();
1357         err = scm_send(sock, msg, siocb->scm);
1358         if (err < 0)
1359                 return err;
1360
1361         err = -EOPNOTSUPP;
1362         if (msg->msg_flags&MSG_OOB)
1363                 goto out;
1364
1365         if (msg->msg_namelen) {
1366                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1367                 if (err < 0)
1368                         goto out;
1369                 namelen = err;
1370         } else {
1371                 sunaddr = NULL;
1372                 err = -ENOTCONN;
1373                 other = unix_peer_get(sk);
1374                 if (!other)
1375                         goto out;
1376         }
1377
1378         if (test_bit(SOCK_PASSCRED, &sock->flags)
1379                 && !u->addr && (err = unix_autobind(sock)) != 0)
1380                 goto out;
1381
1382         err = -EMSGSIZE;
1383         if (len > sk->sk_sndbuf - 32)
1384                 goto out;
1385
1386         skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1387         if (skb == NULL)
1388                 goto out;
1389
1390         memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1391         if (siocb->scm->fp) {
1392                 err = unix_attach_fds(siocb->scm, skb);
1393                 if (err)
1394                         goto out_free;
1395         }
1396         unix_get_secdata(siocb->scm, skb);
1397
1398         skb_reset_transport_header(skb);
1399         err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1400         if (err)
1401                 goto out_free;
1402
1403         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1404
1405 restart:
1406         if (!other) {
1407                 err = -ECONNRESET;
1408                 if (sunaddr == NULL)
1409                         goto out_free;
1410
1411                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1412                                         hash, &err);
1413                 if (other == NULL)
1414                         goto out_free;
1415         }
1416
1417         unix_state_lock(other);
1418         err = -EPERM;
1419         if (!unix_may_send(sk, other))
1420                 goto out_unlock;
1421
1422         if (sock_flag(other, SOCK_DEAD)) {
1423                 /*
1424                  *      Check with 1003.1g - what should
1425                  *      datagram error
1426                  */
1427                 unix_state_unlock(other);
1428                 sock_put(other);
1429
1430                 err = 0;
1431                 unix_state_lock(sk);
1432                 if (unix_peer(sk) == other) {
1433                         unix_peer(sk) = NULL;
1434                         unix_state_unlock(sk);
1435
1436                         unix_dgram_disconnected(sk, other);
1437                         sock_put(other);
1438                         err = -ECONNREFUSED;
1439                 } else {
1440                         unix_state_unlock(sk);
1441                 }
1442
1443                 other = NULL;
1444                 if (err)
1445                         goto out_free;
1446                 goto restart;
1447         }
1448
1449         err = -EPIPE;
1450         if (other->sk_shutdown & RCV_SHUTDOWN)
1451                 goto out_unlock;
1452
1453         if (sk->sk_type != SOCK_SEQPACKET) {
1454                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1455                 if (err)
1456                         goto out_unlock;
1457         }
1458
1459         if (unix_peer(other) != sk && unix_recvq_full(other)) {
1460                 if (!timeo) {
1461                         err = -EAGAIN;
1462                         goto out_unlock;
1463                 }
1464
1465                 timeo = unix_wait_for_peer(other, timeo);
1466
1467                 err = sock_intr_errno(timeo);
1468                 if (signal_pending(current))
1469                         goto out_free;
1470
1471                 goto restart;
1472         }
1473
1474         skb_queue_tail(&other->sk_receive_queue, skb);
1475         unix_state_unlock(other);
1476         other->sk_data_ready(other, len);
1477         sock_put(other);
1478         scm_destroy(siocb->scm);
1479         return len;
1480
1481 out_unlock:
1482         unix_state_unlock(other);
1483 out_free:
1484         kfree_skb(skb);
1485 out:
1486         if (other)
1487                 sock_put(other);
1488         scm_destroy(siocb->scm);
1489         return err;
1490 }
1491
1492
1493 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1494                                struct msghdr *msg, size_t len)
1495 {
1496         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1497         struct sock *sk = sock->sk;
1498         struct sock *other = NULL;
1499         struct sockaddr_un *sunaddr = msg->msg_name;
1500         int err, size;
1501         struct sk_buff *skb;
1502         int sent = 0;
1503         struct scm_cookie tmp_scm;
1504         bool fds_sent = false;
1505
1506         if (NULL == siocb->scm)
1507                 siocb->scm = &tmp_scm;
1508         wait_for_unix_gc();
1509         err = scm_send(sock, msg, siocb->scm);
1510         if (err < 0)
1511                 return err;
1512
1513         err = -EOPNOTSUPP;
1514         if (msg->msg_flags&MSG_OOB)
1515                 goto out_err;
1516
1517         if (msg->msg_namelen) {
1518                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1519                 goto out_err;
1520         } else {
1521                 sunaddr = NULL;
1522                 err = -ENOTCONN;
1523                 other = unix_peer(sk);
1524                 if (!other)
1525                         goto out_err;
1526         }
1527
1528         if (sk->sk_shutdown & SEND_SHUTDOWN)
1529                 goto pipe_err;
1530
1531         while (sent < len) {
1532                 /*
1533                  *      Optimisation for the fact that under 0.01% of X
1534                  *      messages typically need breaking up.
1535                  */
1536
1537                 size = len-sent;
1538
1539                 /* Keep two messages in the pipe so it schedules better */
1540                 if (size > ((sk->sk_sndbuf >> 1) - 64))
1541                         size = (sk->sk_sndbuf >> 1) - 64;
1542
1543                 if (size > SKB_MAX_ALLOC)
1544                         size = SKB_MAX_ALLOC;
1545
1546                 /*
1547                  *      Grab a buffer
1548                  */
1549
1550                 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1551                                           &err);
1552
1553                 if (skb == NULL)
1554                         goto out_err;
1555
1556                 /*
1557                  *      If you pass two values to the sock_alloc_send_skb
1558                  *      it tries to grab the large buffer with GFP_NOFS
1559                  *      (which can fail easily), and if it fails grab the
1560                  *      fallback size buffer which is under a page and will
1561                  *      succeed. [Alan]
1562                  */
1563                 size = min_t(int, size, skb_tailroom(skb));
1564
1565                 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1566                 /* Only send the fds in the first buffer */
1567                 if (siocb->scm->fp && !fds_sent) {
1568                         err = unix_attach_fds(siocb->scm, skb);
1569                         if (err) {
1570                                 kfree_skb(skb);
1571                                 goto out_err;
1572                         }
1573                         fds_sent = true;
1574                 }
1575
1576                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1577                 if (err) {
1578                         kfree_skb(skb);
1579                         goto out_err;
1580                 }
1581
1582                 unix_state_lock(other);
1583
1584                 if (sock_flag(other, SOCK_DEAD) ||
1585                     (other->sk_shutdown & RCV_SHUTDOWN))
1586                         goto pipe_err_free;
1587
1588                 skb_queue_tail(&other->sk_receive_queue, skb);
1589                 unix_state_unlock(other);
1590                 other->sk_data_ready(other, size);
1591                 sent += size;
1592         }
1593
1594         scm_destroy(siocb->scm);
1595         siocb->scm = NULL;
1596
1597         return sent;
1598
1599 pipe_err_free:
1600         unix_state_unlock(other);
1601         kfree_skb(skb);
1602 pipe_err:
1603         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1604                 send_sig(SIGPIPE, current, 0);
1605         err = -EPIPE;
1606 out_err:
1607         scm_destroy(siocb->scm);
1608         siocb->scm = NULL;
1609         return sent ? : err;
1610 }
1611
1612 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1613                                   struct msghdr *msg, size_t len)
1614 {
1615         int err;
1616         struct sock *sk = sock->sk;
1617
1618         err = sock_error(sk);
1619         if (err)
1620                 return err;
1621
1622         if (sk->sk_state != TCP_ESTABLISHED)
1623                 return -ENOTCONN;
1624
1625         if (msg->msg_namelen)
1626                 msg->msg_namelen = 0;
1627
1628         return unix_dgram_sendmsg(kiocb, sock, msg, len);
1629 }
1630
1631 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1632 {
1633         struct unix_sock *u = unix_sk(sk);
1634
1635         msg->msg_namelen = 0;
1636         if (u->addr) {
1637                 msg->msg_namelen = u->addr->len;
1638                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1639         }
1640 }
1641
1642 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1643                               struct msghdr *msg, size_t size,
1644                               int flags)
1645 {
1646         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1647         struct scm_cookie tmp_scm;
1648         struct sock *sk = sock->sk;
1649         struct unix_sock *u = unix_sk(sk);
1650         int noblock = flags & MSG_DONTWAIT;
1651         struct sk_buff *skb;
1652         int err;
1653
1654         err = -EOPNOTSUPP;
1655         if (flags&MSG_OOB)
1656                 goto out;
1657
1658         msg->msg_namelen = 0;
1659
1660         mutex_lock(&u->readlock);
1661
1662         skb = skb_recv_datagram(sk, flags, noblock, &err);
1663         if (!skb) {
1664                 unix_state_lock(sk);
1665                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1666                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1667                     (sk->sk_shutdown & RCV_SHUTDOWN))
1668                         err = 0;
1669                 unix_state_unlock(sk);
1670                 goto out_unlock;
1671         }
1672
1673         wake_up_interruptible_sync(&u->peer_wait);
1674
1675         if (msg->msg_name)
1676                 unix_copy_addr(msg, skb->sk);
1677
1678         if (size > skb->len)
1679                 size = skb->len;
1680         else if (size < skb->len)
1681                 msg->msg_flags |= MSG_TRUNC;
1682
1683         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1684         if (err)
1685                 goto out_free;
1686
1687         if (!siocb->scm) {
1688                 siocb->scm = &tmp_scm;
1689                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1690         }
1691         siocb->scm->creds = *UNIXCREDS(skb);
1692         unix_set_secdata(siocb->scm, skb);
1693
1694         if (!(flags & MSG_PEEK)) {
1695                 if (UNIXCB(skb).fp)
1696                         unix_detach_fds(siocb->scm, skb);
1697         } else {
1698                 /* It is questionable: on PEEK we could:
1699                    - do not return fds - good, but too simple 8)
1700                    - return fds, and do not return them on read (old strategy,
1701                      apparently wrong)
1702                    - clone fds (I chose it for now, it is the most universal
1703                      solution)
1704
1705                    POSIX 1003.1g does not actually define this clearly
1706                    at all. POSIX 1003.1g doesn't define a lot of things
1707                    clearly however!
1708
1709                 */
1710                 if (UNIXCB(skb).fp)
1711                         siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1712         }
1713         err = size;
1714
1715         scm_recv(sock, msg, siocb->scm, flags);
1716
1717 out_free:
1718         skb_free_datagram(sk, skb);
1719 out_unlock:
1720         mutex_unlock(&u->readlock);
1721 out:
1722         return err;
1723 }
1724
1725 /*
1726  *      Sleep until data has arrive. But check for races..
1727  */
1728
1729 static long unix_stream_data_wait(struct sock *sk, long timeo)
1730 {
1731         DEFINE_WAIT(wait);
1732
1733         unix_state_lock(sk);
1734
1735         for (;;) {
1736                 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
1737
1738                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1739                     sk->sk_err ||
1740                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
1741                     signal_pending(current) ||
1742                     !timeo)
1743                         break;
1744
1745                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1746                 unix_state_unlock(sk);
1747                 timeo = schedule_timeout(timeo);
1748                 unix_state_lock(sk);
1749                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1750         }
1751
1752         finish_wait(sk->sk_sleep, &wait);
1753         unix_state_unlock(sk);
1754         return timeo;
1755 }
1756
1757
1758
1759 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1760                                struct msghdr *msg, size_t size,
1761                                int flags)
1762 {
1763         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1764         struct scm_cookie tmp_scm;
1765         struct sock *sk = sock->sk;
1766         struct unix_sock *u = unix_sk(sk);
1767         struct sockaddr_un *sunaddr = msg->msg_name;
1768         int copied = 0;
1769         int check_creds = 0;
1770         int target;
1771         int err = 0;
1772         long timeo;
1773
1774         err = -EINVAL;
1775         if (sk->sk_state != TCP_ESTABLISHED)
1776                 goto out;
1777
1778         err = -EOPNOTSUPP;
1779         if (flags&MSG_OOB)
1780                 goto out;
1781
1782         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1783         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1784
1785         msg->msg_namelen = 0;
1786
1787         /* Lock the socket to prevent queue disordering
1788          * while sleeps in memcpy_tomsg
1789          */
1790
1791         if (!siocb->scm) {
1792                 siocb->scm = &tmp_scm;
1793                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1794         }
1795
1796         mutex_lock(&u->readlock);
1797
1798         do {
1799                 int chunk;
1800                 struct sk_buff *skb;
1801
1802                 unix_state_lock(sk);
1803                 skb = skb_dequeue(&sk->sk_receive_queue);
1804                 if (skb == NULL) {
1805                         if (copied >= target)
1806                                 goto unlock;
1807
1808                         /*
1809                          *      POSIX 1003.1g mandates this order.
1810                          */
1811
1812                         err = sock_error(sk);
1813                         if (err)
1814                                 goto unlock;
1815                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1816                                 goto unlock;
1817
1818                         unix_state_unlock(sk);
1819                         err = -EAGAIN;
1820                         if (!timeo)
1821                                 break;
1822                         mutex_unlock(&u->readlock);
1823
1824                         timeo = unix_stream_data_wait(sk, timeo);
1825
1826                         if (signal_pending(current)) {
1827                                 err = sock_intr_errno(timeo);
1828                                 goto out;
1829                         }
1830                         mutex_lock(&u->readlock);
1831                         continue;
1832  unlock:
1833                         unix_state_unlock(sk);
1834                         break;
1835                 }
1836                 unix_state_unlock(sk);
1837
1838                 if (check_creds) {
1839                         /* Never glue messages from different writers */
1840                         if (memcmp(UNIXCREDS(skb), &siocb->scm->creds,
1841                                    sizeof(siocb->scm->creds)) != 0) {
1842                                 skb_queue_head(&sk->sk_receive_queue, skb);
1843                                 break;
1844                         }
1845                 } else {
1846                         /* Copy credentials */
1847                         siocb->scm->creds = *UNIXCREDS(skb);
1848                         check_creds = 1;
1849                 }
1850
1851                 /* Copy address just once */
1852                 if (sunaddr) {
1853                         unix_copy_addr(msg, skb->sk);
1854                         sunaddr = NULL;
1855                 }
1856
1857                 chunk = min_t(unsigned int, skb->len, size);
1858                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1859                         skb_queue_head(&sk->sk_receive_queue, skb);
1860                         if (copied == 0)
1861                                 copied = -EFAULT;
1862                         break;
1863                 }
1864                 copied += chunk;
1865                 size -= chunk;
1866
1867                 /* Mark read part of skb as used */
1868                 if (!(flags & MSG_PEEK)) {
1869                         skb_pull(skb, chunk);
1870
1871                         if (UNIXCB(skb).fp)
1872                                 unix_detach_fds(siocb->scm, skb);
1873
1874                         /* put the skb back if we didn't use it up.. */
1875                         if (skb->len) {
1876                                 skb_queue_head(&sk->sk_receive_queue, skb);
1877                                 break;
1878                         }
1879
1880                         kfree_skb(skb);
1881
1882                         if (siocb->scm->fp)
1883                                 break;
1884                 } else {
1885                         /* It is questionable, see note in unix_dgram_recvmsg.
1886                          */
1887                         if (UNIXCB(skb).fp)
1888                                 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1889
1890                         /* put message back and return */
1891                         skb_queue_head(&sk->sk_receive_queue, skb);
1892                         break;
1893                 }
1894         } while (size);
1895
1896         mutex_unlock(&u->readlock);
1897         scm_recv(sock, msg, siocb->scm, flags);
1898 out:
1899         return copied ? : err;
1900 }
1901
1902 static int unix_shutdown(struct socket *sock, int mode)
1903 {
1904         struct sock *sk = sock->sk;
1905         struct sock *other;
1906
1907         mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1908
1909         if (mode) {
1910                 unix_state_lock(sk);
1911                 sk->sk_shutdown |= mode;
1912                 other = unix_peer(sk);
1913                 if (other)
1914                         sock_hold(other);
1915                 unix_state_unlock(sk);
1916                 sk->sk_state_change(sk);
1917
1918                 if (other &&
1919                         (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1920
1921                         int peer_mode = 0;
1922
1923                         if (mode&RCV_SHUTDOWN)
1924                                 peer_mode |= SEND_SHUTDOWN;
1925                         if (mode&SEND_SHUTDOWN)
1926                                 peer_mode |= RCV_SHUTDOWN;
1927                         unix_state_lock(other);
1928                         other->sk_shutdown |= peer_mode;
1929                         unix_state_unlock(other);
1930                         other->sk_state_change(other);
1931                         read_lock(&other->sk_callback_lock);
1932                         if (peer_mode == SHUTDOWN_MASK)
1933                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1934                         else if (peer_mode & RCV_SHUTDOWN)
1935                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
1936                         read_unlock(&other->sk_callback_lock);
1937                 }
1938                 if (other)
1939                         sock_put(other);
1940         }
1941         return 0;
1942 }
1943
1944 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1945 {
1946         struct sock *sk = sock->sk;
1947         long amount = 0;
1948         int err;
1949
1950         switch (cmd) {
1951         case SIOCOUTQ:
1952                 amount = sk_wmem_alloc_get(sk);
1953                 err = put_user(amount, (int __user *)arg);
1954                 break;
1955         case SIOCINQ:
1956                 {
1957                         struct sk_buff *skb;
1958
1959                         if (sk->sk_state == TCP_LISTEN) {
1960                                 err = -EINVAL;
1961                                 break;
1962                         }
1963
1964                         spin_lock(&sk->sk_receive_queue.lock);
1965                         if (sk->sk_type == SOCK_STREAM ||
1966                             sk->sk_type == SOCK_SEQPACKET) {
1967                                 skb_queue_walk(&sk->sk_receive_queue, skb)
1968                                         amount += skb->len;
1969                         } else {
1970                                 skb = skb_peek(&sk->sk_receive_queue);
1971                                 if (skb)
1972                                         amount = skb->len;
1973                         }
1974                         spin_unlock(&sk->sk_receive_queue.lock);
1975                         err = put_user(amount, (int __user *)arg);
1976                         break;
1977                 }
1978
1979         default:
1980                 err = -ENOIOCTLCMD;
1981                 break;
1982         }
1983         return err;
1984 }
1985
1986 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
1987 {
1988         struct sock *sk = sock->sk;
1989         unsigned int mask;
1990
1991         sock_poll_wait(file, sk->sk_sleep, wait);
1992         mask = 0;
1993
1994         /* exceptional events? */
1995         if (sk->sk_err)
1996                 mask |= POLLERR;
1997         if (sk->sk_shutdown == SHUTDOWN_MASK)
1998                 mask |= POLLHUP;
1999         if (sk->sk_shutdown & RCV_SHUTDOWN)
2000                 mask |= POLLRDHUP;
2001
2002         /* readable? */
2003         if (!skb_queue_empty(&sk->sk_receive_queue) ||
2004             (sk->sk_shutdown & RCV_SHUTDOWN))
2005                 mask |= POLLIN | POLLRDNORM;
2006
2007         /* Connection-based need to check for termination and startup */
2008         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2009             sk->sk_state == TCP_CLOSE)
2010                 mask |= POLLHUP;
2011
2012         /*
2013          * we set writable also when the other side has shut down the
2014          * connection. This prevents stuck sockets.
2015          */
2016         if (unix_writable(sk))
2017                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2018
2019         return mask;
2020 }
2021
2022 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2023                                     poll_table *wait)
2024 {
2025         struct sock *sk = sock->sk, *other;
2026         unsigned int mask, writable;
2027
2028         sock_poll_wait(file, sk->sk_sleep, wait);
2029         mask = 0;
2030
2031         /* exceptional events? */
2032         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2033                 mask |= POLLERR;
2034         if (sk->sk_shutdown & RCV_SHUTDOWN)
2035                 mask |= POLLRDHUP;
2036         if (sk->sk_shutdown == SHUTDOWN_MASK)
2037                 mask |= POLLHUP;
2038
2039         /* readable? */
2040         if (!skb_queue_empty(&sk->sk_receive_queue) ||
2041             (sk->sk_shutdown & RCV_SHUTDOWN))
2042                 mask |= POLLIN | POLLRDNORM;
2043
2044         /* Connection-based need to check for termination and startup */
2045         if (sk->sk_type == SOCK_SEQPACKET) {
2046                 if (sk->sk_state == TCP_CLOSE)
2047                         mask |= POLLHUP;
2048                 /* connection hasn't started yet? */
2049                 if (sk->sk_state == TCP_SYN_SENT)
2050                         return mask;
2051         }
2052
2053         /* writable? */
2054         writable = unix_writable(sk);
2055         if (writable) {
2056                 other = unix_peer_get(sk);
2057                 if (other) {
2058                         if (unix_peer(other) != sk) {
2059                                 sock_poll_wait(file, &unix_sk(other)->peer_wait,
2060                                           wait);
2061                                 if (unix_recvq_full(other))
2062                                         writable = 0;
2063                         }
2064
2065                         sock_put(other);
2066                 }
2067         }
2068
2069         if (writable)
2070                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2071         else
2072                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2073
2074         return mask;
2075 }
2076
2077 #ifdef CONFIG_PROC_FS
2078 static struct sock *first_unix_socket(int *i)
2079 {
2080         for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2081                 if (!hlist_empty(&unix_socket_table[*i]))
2082                         return __sk_head(&unix_socket_table[*i]);
2083         }
2084         return NULL;
2085 }
2086
2087 static struct sock *next_unix_socket(int *i, struct sock *s)
2088 {
2089         struct sock *next = sk_next(s);
2090         /* More in this chain? */
2091         if (next)
2092                 return next;
2093         /* Look for next non-empty chain. */
2094         for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2095                 if (!hlist_empty(&unix_socket_table[*i]))
2096                         return __sk_head(&unix_socket_table[*i]);
2097         }
2098         return NULL;
2099 }
2100
2101 struct unix_iter_state {
2102         struct seq_net_private p;
2103         int i;
2104 };
2105
2106 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2107 {
2108         struct unix_iter_state *iter = seq->private;
2109         loff_t off = 0;
2110         struct sock *s;
2111
2112         for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2113                 if (sock_net(s) != seq_file_net(seq))
2114                         continue;
2115                 if (off == pos)
2116                         return s;
2117                 ++off;
2118         }
2119         return NULL;
2120 }
2121
2122 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2123         __acquires(unix_table_lock)
2124 {
2125         spin_lock(&unix_table_lock);
2126         return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2127 }
2128
2129 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2130 {
2131         struct unix_iter_state *iter = seq->private;
2132         struct sock *sk = v;
2133         ++*pos;
2134
2135         if (v == SEQ_START_TOKEN)
2136                 sk = first_unix_socket(&iter->i);
2137         else
2138                 sk = next_unix_socket(&iter->i, sk);
2139         while (sk && (sock_net(sk) != seq_file_net(seq)))
2140                 sk = next_unix_socket(&iter->i, sk);
2141         return sk;
2142 }
2143
2144 static void unix_seq_stop(struct seq_file *seq, void *v)
2145         __releases(unix_table_lock)
2146 {
2147         spin_unlock(&unix_table_lock);
2148 }
2149
2150 static int unix_seq_show(struct seq_file *seq, void *v)
2151 {
2152
2153         if (v == SEQ_START_TOKEN)
2154                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2155                          "Inode Path\n");
2156         else {
2157                 struct sock *s = v;
2158                 struct unix_sock *u = unix_sk(s);
2159                 unix_state_lock(s);
2160
2161                 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2162                         s,
2163                         atomic_read(&s->sk_refcnt),
2164                         0,
2165                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2166                         s->sk_type,
2167                         s->sk_socket ?
2168                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2169                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2170                         sock_i_ino(s));
2171
2172                 if (u->addr) {
2173                         int i, len;
2174                         seq_putc(seq, ' ');
2175
2176                         i = 0;
2177                         len = u->addr->len - sizeof(short);
2178                         if (!UNIX_ABSTRACT(s))
2179                                 len--;
2180                         else {
2181                                 seq_putc(seq, '@');
2182                                 i++;
2183                         }
2184                         for ( ; i < len; i++)
2185                                 seq_putc(seq, u->addr->name->sun_path[i]);
2186                 }
2187                 unix_state_unlock(s);
2188                 seq_putc(seq, '\n');
2189         }
2190
2191         return 0;
2192 }
2193
2194 static const struct seq_operations unix_seq_ops = {
2195         .start  = unix_seq_start,
2196         .next   = unix_seq_next,
2197         .stop   = unix_seq_stop,
2198         .show   = unix_seq_show,
2199 };
2200
2201 static int unix_seq_open(struct inode *inode, struct file *file)
2202 {
2203         return seq_open_net(inode, file, &unix_seq_ops,
2204                             sizeof(struct unix_iter_state));
2205 }
2206
2207 static const struct file_operations unix_seq_fops = {
2208         .owner          = THIS_MODULE,
2209         .open           = unix_seq_open,
2210         .read           = seq_read,
2211         .llseek         = seq_lseek,
2212         .release        = seq_release_net,
2213 };
2214
2215 #endif
2216
2217 static struct net_proto_family unix_family_ops = {
2218         .family = PF_UNIX,
2219         .create = unix_create,
2220         .owner  = THIS_MODULE,
2221 };
2222
2223
2224 static int unix_net_init(struct net *net)
2225 {
2226         int error = -ENOMEM;
2227
2228         net->unx.sysctl_max_dgram_qlen = 10;
2229         if (unix_sysctl_register(net))
2230                 goto out;
2231
2232 #ifdef CONFIG_PROC_FS
2233         if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2234                 unix_sysctl_unregister(net);
2235                 goto out;
2236         }
2237 #endif
2238         error = 0;
2239 out:
2240         return error;
2241 }
2242
2243 static void unix_net_exit(struct net *net)
2244 {
2245         unix_sysctl_unregister(net);
2246         proc_net_remove(net, "unix");
2247 }
2248
2249 static struct pernet_operations unix_net_ops = {
2250         .init = unix_net_init,
2251         .exit = unix_net_exit,
2252 };
2253
2254 static int __init af_unix_init(void)
2255 {
2256         int rc = -1;
2257         struct sk_buff *dummy_skb;
2258
2259         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2260
2261         rc = proto_register(&unix_proto, 1);
2262         if (rc != 0) {
2263                 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2264                        __func__);
2265                 goto out;
2266         }
2267
2268         sock_register(&unix_family_ops);
2269         register_pernet_subsys(&unix_net_ops);
2270 out:
2271         return rc;
2272 }
2273
2274 static void __exit af_unix_exit(void)
2275 {
2276         sock_unregister(PF_UNIX);
2277         proto_unregister(&unix_proto);
2278         unregister_pernet_subsys(&unix_net_ops);
2279 }
2280
2281 /* Earlier than device_initcall() so that other drivers invoking
2282    request_module() don't end up in a loop when modprobe tries
2283    to use a UNIX socket. But later than subsys_initcall() because
2284    we depend on stuff initialised there */
2285 fs_initcall(af_unix_init);
2286 module_exit(af_unix_exit);
2287
2288 MODULE_LICENSE("GPL");
2289 MODULE_ALIAS_NETPROTO(PF_UNIX);