net/unix/af_unix.c

   1 /*
   2  * NET4:        Implementation of BSD Unix domain sockets.
   3  *
   4  * Authors:     Alan Cox, <alan.cox@linux.org>
   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  * Version:     $Id: af_unix.c,v 1.133 2002/02/08 03:57:19 davem Exp $
  12  *
  13  * Fixes:
  14  *              Linus Torvalds  :       Assorted bug cures.
  15  *              Niibe Yutaka    :       async I/O support.
  16  *              Carsten Paeth   :       PF_UNIX check, address fixes.
  17  *              Alan Cox        :       Limit size of allocated blocks.
  18  *              Alan Cox        :       Fixed the stupid socketpair bug.
  19  *              Alan Cox        :       BSD compatibility fine tuning.
  20  *              Alan Cox        :       Fixed a bug in connect when interrupted.
  21  *              Alan Cox        :       Sorted out a proper draft version of
  22  *                                      file descriptor passing hacked up from
  23  *                                      Mike Shaver's work.
  24  *              Marty Leisner   :       Fixes to fd passing
  25  *              Nick Nevin      :       recvmsg bugfix.
  26  *              Alan Cox        :       Started proper garbage collector
  27  *              Heiko EiBfeldt  :       Missing verify_area check
  28  *              Alan Cox        :       Started POSIXisms
  29  *              Andreas Schwab  :       Replace inode by dentry for proper
  30  *                                      reference counting
  31  *              Kirk Petersen   :       Made this a module
  32  *          Christoph Rohland   :       Elegant non-blocking accept/connect algorithm.
  33  *                                      Lots of bug fixes.
  34  *           Alexey Kuznetosv   :       Repaired (I hope) bugs introduces
  35  *                                      by above two patches.
  36  *           Andrea Arcangeli   :       If possible we block in connect(2)
  37  *                                      if the max backlog of the listen socket
  38  *                                      is been reached. This won't break
  39  *                                      old apps and it will avoid huge amount
  40  *                                      of socks hashed (this for unix_gc()
  41  *                                      performances reasons).
  42  *                                      Security fix that limits the max
  43  *                                      number of socks to 2*max_files and
  44  *                                      the number of skb queueable in the
  45  *                                      dgram receiver.
  46  *              Artur Skawina   :       Hash function optimizations
  47  *           Alexey Kuznetsov   :       Full scale SMP. Lot of bugs are introduced 8)
  48  *            Malcolm Beattie   :       Set peercred for socketpair
  49  *           Michal Ostrowski   :       Module initialization cleanup.
  50  *           Arnaldo C. Melo    :       Remove MOD_{INC,DEC}_USE_COUNT,
  51  *                                      the core infrastructure is doing that
  52  *                                      for all net proto families now (2.5.69+)
  53  *
  54  *
  55  * Known differences from reference BSD that was tested:
  56  *
  57  *      [TO FIX]
  58  *      ECONNREFUSED is not returned from one end of a connected() socket to the
  59  *              other the moment one end closes.
  60  *      fstat() doesn't return st_dev=0, and give the blksize as high water mark
  61  *              and a fake inode identifier (nor the BSD first socket fstat twice bug).
  62  *      [NOT TO FIX]
  63  *      accept() returns a path name even if the connecting socket has closed
  64  *              in the meantime (BSD loses the path and gives up).
  65  *      accept() returns 0 length path for an unbound connector. BSD returns 16
  66  *              and a null first byte in the path (but not for gethost/peername - BSD bug ??)
  67  *      socketpair(...SOCK_RAW..) doesn't panic the kernel.
  68  *      BSD af_unix apparently has connect forgetting to block properly.
  69  *              (need to check this with the POSIX spec in detail)
  70  *
  71  * Differences from 2.0.0-11-... (ANK)
  72  *      Bug fixes and improvements.
  73  *              - client shutdown killed server socket.
  74  *              - removed all useless cli/sti pairs.
  75  *
  76  *      Semantic changes/extensions.
  77  *              - generic control message passing.
  78  *              - SCM_CREDENTIALS control message.
  79  *              - "Abstract" (not FS based) socket bindings.
  80  *                Abstract names are sequences of bytes (not zero terminated)
  81  *                started by 0, so that this name space does not intersect
  82  *                with BSD names.
  83  */
  84
  85 #include <linux/module.h>
  86 #include <linux/kernel.h>
  87 #include <linux/signal.h>
  88 #include <linux/sched.h>
  89 #include <linux/errno.h>
  90 #include <linux/string.h>
  91 #include <linux/stat.h>
  92 #include <linux/dcache.h>
  93 #include <linux/namei.h>
  94 #include <linux/socket.h>
  95 #include <linux/un.h>
  96 #include <linux/fcntl.h>
  97 #include <linux/termios.h>
  98 #include <linux/sockios.h>
  99 #include <linux/net.h>
 100 #include <linux/in.h>
 101 #include <linux/fs.h>
 102 #include <linux/slab.h>
 103 #include <asm/uaccess.h>
 104 #include <linux/skbuff.h>
 105 #include <linux/netdevice.h>
 106 #include <net/net_namespace.h>
 107 #include <net/sock.h>
 108 #include <net/tcp_states.h>
 109 #include <net/af_unix.h>
 110 #include <linux/proc_fs.h>
 111 #include <linux/seq_file.h>
 112 #include <net/scm.h>
 113 #include <linux/init.h>
 114 #include <linux/poll.h>
 115 #include <linux/rtnetlink.h>
 116 #include <linux/mount.h>
 117 #include <net/checksum.h>
 118 #include <linux/security.h>
 119
 120 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
 121 static DEFINE_SPINLOCK(unix_table_lock);
 122 static atomic_t unix_nr_socks = ATOMIC_INIT(0);
 123
 124 #define unix_sockets_unbound    (&unix_socket_table[UNIX_HASH_SIZE])
 125
 126 #define UNIX_ABSTRACT(sk)       (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
 127
 128 #ifdef CONFIG_SECURITY_NETWORK
 129 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 130 {
 131         memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
 132 }
 133
 134 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 135 {
 136         scm->secid = *UNIXSID(skb);
 137 }
 138 #else
 139 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 140 { }
 141
 142 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 143 { }
 144 #endif /* CONFIG_SECURITY_NETWORK */
 145
 146 /*
 147  *  SMP locking strategy:
 148  *    hash table is protected with spinlock unix_table_lock
 149  *    each socket state is protected by separate rwlock.
 150  */
 151
 152 static inline unsigned unix_hash_fold(__wsum n)
 153 {
 154         unsigned hash = (__force unsigned)n;
 155         hash ^= hash>>16;
 156         hash ^= hash>>8;
 157         return hash&(UNIX_HASH_SIZE-1);
 158 }
 159
 160 #define unix_peer(sk) (unix_sk(sk)->peer)
 161
 162 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
 163 {
 164         return unix_peer(osk) == sk;
 165 }
 166
 167 static inline int unix_may_send(struct sock *sk, struct sock *osk)
 168 {
 169         return (unix_peer(osk) == NULL || unix_our_peer(sk, osk));
 170 }
 171
 172 static inline int unix_recvq_full(struct sock const *sk)
 173 {
 174         return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
 175 }
 176
 177 static struct sock *unix_peer_get(struct sock *s)
 178 {
 179         struct sock *peer;
 180
 181         unix_state_lock(s);
 182         peer = unix_peer(s);
 183         if (peer)
 184                 sock_hold(peer);
 185         unix_state_unlock(s);
 186         return peer;
 187 }
 188
 189 static inline void unix_release_addr(struct unix_address *addr)
 190 {
 191         if (atomic_dec_and_test(&addr->refcnt))
 192                 kfree(addr);
 193 }
 194
 195 /*
 196  *      Check unix socket name:
 197  *              - should be not zero length.
 198  *              - if started by not zero, should be NULL terminated (FS object)
 199  *              - if started by zero, it is abstract name.
 200  */
 201
 202 static int unix_mkname(struct sockaddr_un * sunaddr, int len, unsigned *hashp)
 203 {
 204         if (len <= sizeof(short) || len > sizeof(*sunaddr))
 205                 return -EINVAL;
 206         if (!sunaddr || sunaddr->sun_family != AF_UNIX)
 207                 return -EINVAL;
 208         if (sunaddr->sun_path[0]) {
 209                 /*
 210                  * This may look like an off by one error but it is a bit more
 211                  * subtle. 108 is the longest valid AF_UNIX path for a binding.
 212                  * sun_path[108] doesnt as such exist.  However in kernel space
 213                  * we are guaranteed that it is a valid memory location in our
 214                  * kernel address buffer.
 215                  */
 216                 ((char *)sunaddr)[len]=0;
 217                 len = strlen(sunaddr->sun_path)+1+sizeof(short);
 218                 return len;
 219         }
 220
 221         *hashp = unix_hash_fold(csum_partial((char*)sunaddr, len, 0));
 222         return len;
 223 }
 224
 225 static void __unix_remove_socket(struct sock *sk)
 226 {
 227         sk_del_node_init(sk);
 228 }
 229
 230 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
 231 {
 232         BUG_TRAP(sk_unhashed(sk));
 233         sk_add_node(sk, list);
 234 }
 235
 236 static inline void unix_remove_socket(struct sock *sk)
 237 {
 238         spin_lock(&unix_table_lock);
 239         __unix_remove_socket(sk);
 240         spin_unlock(&unix_table_lock);
 241 }
 242
 243 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
 244 {
 245         spin_lock(&unix_table_lock);
 246         __unix_insert_socket(list, sk);
 247         spin_unlock(&unix_table_lock);
 248 }
 249
 250 static struct sock *__unix_find_socket_byname(struct net *net,
 251                                               struct sockaddr_un *sunname,
 252                                               int len, int type, unsigned hash)
 253 {
 254         struct sock *s;
 255         struct hlist_node *node;
 256
 257         sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
 258                 struct unix_sock *u = unix_sk(s);
 259
 260                 if (!net_eq(sock_net(s), net))
 261                         continue;
 262
 263                 if (u->addr->len == len &&
 264                     !memcmp(u->addr->name, sunname, len))
 265                         goto found;
 266         }
 267         s = NULL;
 268 found:
 269         return s;
 270 }
 271
 272 static inline struct sock *unix_find_socket_byname(struct net *net,
 273                                                    struct sockaddr_un *sunname,
 274                                                    int len, int type,
 275                                                    unsigned hash)
 276 {
 277         struct sock *s;
 278
 279         spin_lock(&unix_table_lock);
 280         s = __unix_find_socket_byname(net, sunname, len, type, hash);
 281         if (s)
 282                 sock_hold(s);
 283         spin_unlock(&unix_table_lock);
 284         return s;
 285 }
 286
 287 static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
 288 {
 289         struct sock *s;
 290         struct hlist_node *node;
 291
 292         spin_lock(&unix_table_lock);
 293         sk_for_each(s, node,
 294                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
 295                 struct dentry *dentry = unix_sk(s)->dentry;
 296
 297                 if (!net_eq(sock_net(s), net))
 298                         continue;
 299
 300                 if(dentry && dentry->d_inode == i)
 301                 {
 302                         sock_hold(s);
 303                         goto found;
 304                 }
 305         }
 306         s = NULL;
 307 found:
 308         spin_unlock(&unix_table_lock);
 309         return s;
 310 }
 311
 312 static inline int unix_writable(struct sock *sk)
 313 {
 314         return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
 315 }
 316
 317 static void unix_write_space(struct sock *sk)
 318 {
 319         read_lock(&sk->sk_callback_lock);
 320         if (unix_writable(sk)) {
 321                 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 322                         wake_up_interruptible_sync(sk->sk_sleep);
 323                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 324         }
 325         read_unlock(&sk->sk_callback_lock);
 326 }
 327
 328 /* When dgram socket disconnects (or changes its peer), we clear its receive
 329  * queue of packets arrived from previous peer. First, it allows to do
 330  * flow control based only on wmem_alloc; second, sk connected to peer
 331  * may receive messages only from that peer. */
 332 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
 333 {
 334         if (!skb_queue_empty(&sk->sk_receive_queue)) {
 335                 skb_queue_purge(&sk->sk_receive_queue);
 336                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
 337
 338                 /* If one link of bidirectional dgram pipe is disconnected,
 339                  * we signal error. Messages are lost. Do not make this,
 340                  * when peer was not connected to us.
 341                  */
 342                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
 343                         other->sk_err = ECONNRESET;
 344                         other->sk_error_report(other);
 345                 }
 346         }
 347 }
 348
 349 static void unix_sock_destructor(struct sock *sk)
 350 {
 351         struct unix_sock *u = unix_sk(sk);
 352
 353         skb_queue_purge(&sk->sk_receive_queue);
 354
 355         BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
 356         BUG_TRAP(sk_unhashed(sk));
 357         BUG_TRAP(!sk->sk_socket);
 358         if (!sock_flag(sk, SOCK_DEAD)) {
 359                 printk("Attempt to release alive unix socket: %p\n", sk);
 360                 return;
 361         }
 362
 363         if (u->addr)
 364                 unix_release_addr(u->addr);
 365
 366         atomic_dec(&unix_nr_socks);
 367 #ifdef UNIX_REFCNT_DEBUG
 368         printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk, atomic_read(&unix_nr_socks));
 369 #endif
 370 }
 371
 372 static int unix_release_sock (struct sock *sk, int embrion)
 373 {
 374         struct unix_sock *u = unix_sk(sk);
 375         struct dentry *dentry;
 376         struct vfsmount *mnt;
 377         struct sock *skpair;
 378         struct sk_buff *skb;
 379         int state;
 380
 381         unix_remove_socket(sk);
 382
 383         /* Clear state */
 384         unix_state_lock(sk);
 385         sock_orphan(sk);
 386         sk->sk_shutdown = SHUTDOWN_MASK;
 387         dentry       = u->dentry;
 388         u->dentry    = NULL;
 389         mnt          = u->mnt;
 390         u->mnt       = NULL;
 391         state = sk->sk_state;
 392         sk->sk_state = TCP_CLOSE;
 393         unix_state_unlock(sk);
 394
 395         wake_up_interruptible_all(&u->peer_wait);
 396
 397         skpair=unix_peer(sk);
 398
 399         if (skpair!=NULL) {
 400                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
 401                         unix_state_lock(skpair);
 402                         /* No more writes */
 403                         skpair->sk_shutdown = SHUTDOWN_MASK;
 404                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 405                                 skpair->sk_err = ECONNRESET;
 406                         unix_state_unlock(skpair);
 407                         skpair->sk_state_change(skpair);
 408                         read_lock(&skpair->sk_callback_lock);
 409                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
 410                         read_unlock(&skpair->sk_callback_lock);
 411                 }
 412                 sock_put(skpair); /* It may now die */
 413                 unix_peer(sk) = NULL;
 414         }
 415
 416         /* Try to flush out this socket. Throw out buffers at least */
 417
 418         while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
 419                 if (state==TCP_LISTEN)
 420                         unix_release_sock(skb->sk, 1);
 421                 /* passed fds are erased in the kfree_skb hook        */
 422                 kfree_skb(skb);
 423         }
 424
 425         if (dentry) {
 426                 dput(dentry);
 427                 mntput(mnt);
 428         }
 429
 430         sock_put(sk);
 431
 432         /* ---- Socket is dead now and most probably destroyed ---- */
 433
 434         /*
 435          * Fixme: BSD difference: In BSD all sockets connected to use get
 436          *        ECONNRESET and we die on the spot. In Linux we behave
 437          *        like files and pipes do and wait for the last
 438          *        dereference.
 439          *
 440          * Can't we simply set sock->err?
 441          *
 442          *        What the above comment does talk about? --ANK(980817)
 443          */
 444
 445         if (unix_tot_inflight)
 446                 unix_gc();              /* Garbage collect fds */
 447
 448         return 0;
 449 }
 450
 451 static int unix_listen(struct socket *sock, int backlog)
 452 {
 453         int err;
 454         struct sock *sk = sock->sk;
 455         struct unix_sock *u = unix_sk(sk);
 456
 457         err = -EOPNOTSUPP;
 458         if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
 459                 goto out;                       /* Only stream/seqpacket sockets accept */
 460         err = -EINVAL;
 461         if (!u->addr)
 462                 goto out;                       /* No listens on an unbound socket */
 463         unix_state_lock(sk);
 464         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
 465                 goto out_unlock;
 466         if (backlog > sk->sk_max_ack_backlog)
 467                 wake_up_interruptible_all(&u->peer_wait);
 468         sk->sk_max_ack_backlog  = backlog;
 469         sk->sk_state            = TCP_LISTEN;
 470         /* set credentials so connect can copy them */
 471         sk->sk_peercred.pid     = task_tgid_vnr(current);
 472         sk->sk_peercred.uid     = current->euid;
 473         sk->sk_peercred.gid     = current->egid;
 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_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         return sk;
 617 }
 618
 619 static int unix_create(struct net *net, struct socket *sock, int protocol)
 620 {
 621         if (protocol && protocol != PF_UNIX)
 622                 return -EPROTONOSUPPORT;
 623
 624         sock->state = SS_UNCONNECTED;
 625
 626         switch (sock->type) {
 627         case SOCK_STREAM:
 628                 sock->ops = &unix_stream_ops;
 629                 break;
 630                 /*
 631                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
 632                  *      nothing uses it.
 633                  */
 634         case SOCK_RAW:
 635                 sock->type=SOCK_DGRAM;
 636         case SOCK_DGRAM:
 637                 sock->ops = &unix_dgram_ops;
 638                 break;
 639         case SOCK_SEQPACKET:
 640                 sock->ops = &unix_seqpacket_ops;
 641                 break;
 642         default:
 643                 return -ESOCKTNOSUPPORT;
 644         }
 645
 646         return unix_create1(net, sock) ? 0 : -ENOMEM;
 647 }
 648
 649 static int unix_release(struct socket *sock)
 650 {
 651         struct sock *sk = sock->sk;
 652
 653         if (!sk)
 654                 return 0;
 655
 656         sock->sk = NULL;
 657
 658         return unix_release_sock (sk, 0);
 659 }
 660
 661 static int unix_autobind(struct socket *sock)
 662 {
 663         struct sock *sk = sock->sk;
 664         struct net *net = sock_net(sk);
 665         struct unix_sock *u = unix_sk(sk);
 666         static u32 ordernum = 1;
 667         struct unix_address * addr;
 668         int err;
 669
 670         mutex_lock(&u->readlock);
 671
 672         err = 0;
 673         if (u->addr)
 674                 goto out;
 675
 676         err = -ENOMEM;
 677         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
 678         if (!addr)
 679                 goto out;
 680
 681         addr->name->sun_family = AF_UNIX;
 682         atomic_set(&addr->refcnt, 1);
 683
 684 retry:
 685         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
 686         addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0));
 687
 688         spin_lock(&unix_table_lock);
 689         ordernum = (ordernum+1)&0xFFFFF;
 690
 691         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
 692                                       addr->hash)) {
 693                 spin_unlock(&unix_table_lock);
 694                 /* Sanity yield. It is unusual case, but yet... */
 695                 if (!(ordernum&0xFF))
 696                         yield();
 697                 goto retry;
 698         }
 699         addr->hash ^= sk->sk_type;
 700
 701         __unix_remove_socket(sk);
 702         u->addr = addr;
 703         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
 704         spin_unlock(&unix_table_lock);
 705         err = 0;
 706
 707 out:    mutex_unlock(&u->readlock);
 708         return err;
 709 }
 710
 711 static struct sock *unix_find_other(struct net *net,
 712                                     struct sockaddr_un *sunname, int len,
 713                                     int type, unsigned hash, int *error)
 714 {
 715         struct sock *u;
 716         struct nameidata nd;
 717         int err = 0;
 718
 719         if (sunname->sun_path[0]) {
 720                 err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd);
 721                 if (err)
 722                         goto fail;
 723                 err = vfs_permission(&nd, MAY_WRITE);
 724                 if (err)
 725                         goto put_fail;
 726
 727                 err = -ECONNREFUSED;
 728                 if (!S_ISSOCK(nd.path.dentry->d_inode->i_mode))
 729                         goto put_fail;
 730                 u = unix_find_socket_byinode(net, nd.path.dentry->d_inode);
 731                 if (!u)
 732                         goto put_fail;
 733
 734                 if (u->sk_type == type)
 735                         touch_atime(nd.path.mnt, nd.path.dentry);
 736
 737                 path_put(&nd.path);
 738
 739                 err=-EPROTOTYPE;
 740                 if (u->sk_type != type) {
 741                         sock_put(u);
 742                         goto fail;
 743                 }
 744         } else {
 745                 err = -ECONNREFUSED;
 746                 u=unix_find_socket_byname(net, sunname, len, type, hash);
 747                 if (u) {
 748                         struct dentry *dentry;
 749                         dentry = unix_sk(u)->dentry;
 750                         if (dentry)
 751                                 touch_atime(unix_sk(u)->mnt, dentry);
 752                 } else
 753                         goto fail;
 754         }
 755         return u;
 756
 757 put_fail:
 758         path_put(&nd.path);
 759 fail:
 760         *error=err;
 761         return NULL;
 762 }
 763
 764
 765 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 766 {
 767         struct sock *sk = sock->sk;
 768         struct net *net = sock_net(sk);
 769         struct unix_sock *u = unix_sk(sk);
 770         struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
 771         struct dentry * dentry = NULL;
 772         struct nameidata nd;
 773         int err;
 774         unsigned hash;
 775         struct unix_address *addr;
 776         struct hlist_head *list;
 777
 778         err = -EINVAL;
 779         if (sunaddr->sun_family != AF_UNIX)
 780                 goto out;
 781
 782         if (addr_len==sizeof(short)) {
 783                 err = unix_autobind(sock);
 784                 goto out;
 785         }
 786
 787         err = unix_mkname(sunaddr, addr_len, &hash);
 788         if (err < 0)
 789                 goto out;
 790         addr_len = err;
 791
 792         mutex_lock(&u->readlock);
 793
 794         err = -EINVAL;
 795         if (u->addr)
 796                 goto out_up;
 797
 798         err = -ENOMEM;
 799         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
 800         if (!addr)
 801                 goto out_up;
 802
 803         memcpy(addr->name, sunaddr, addr_len);
 804         addr->len = addr_len;
 805         addr->hash = hash ^ sk->sk_type;
 806         atomic_set(&addr->refcnt, 1);
 807
 808         if (sunaddr->sun_path[0]) {
 809                 unsigned int mode;
 810                 err = 0;
 811                 /*
 812                  * Get the parent directory, calculate the hash for last
 813                  * component.
 814                  */
 815                 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
 816                 if (err)
 817                         goto out_mknod_parent;
 818
 819                 dentry = lookup_create(&nd, 0);
 820                 err = PTR_ERR(dentry);
 821                 if (IS_ERR(dentry))
 822                         goto out_mknod_unlock;
 823
 824                 /*
 825                  * All right, let's create it.
 826                  */
 827                 mode = S_IFSOCK |
 828                        (SOCK_INODE(sock)->i_mode & ~current->fs->umask);
 829                 err = mnt_want_write(nd.path.mnt);
 830                 if (err)
 831                         goto out_mknod_dput;
 832                 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
 833                 mnt_drop_write(nd.path.mnt);
 834                 if (err)
 835                         goto out_mknod_dput;
 836                 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 837                 dput(nd.path.dentry);
 838                 nd.path.dentry = dentry;
 839
 840                 addr->hash = UNIX_HASH_SIZE;
 841         }
 842
 843         spin_lock(&unix_table_lock);
 844
 845         if (!sunaddr->sun_path[0]) {
 846                 err = -EADDRINUSE;
 847                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
 848                                               sk->sk_type, hash)) {
 849                         unix_release_addr(addr);
 850                         goto out_unlock;
 851                 }
 852
 853                 list = &unix_socket_table[addr->hash];
 854         } else {
 855                 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
 856                 u->dentry = nd.path.dentry;
 857                 u->mnt    = nd.path.mnt;
 858         }
 859
 860         err = 0;
 861         __unix_remove_socket(sk);
 862         u->addr = addr;
 863         __unix_insert_socket(list, sk);
 864
 865 out_unlock:
 866         spin_unlock(&unix_table_lock);
 867 out_up:
 868         mutex_unlock(&u->readlock);
 869 out:
 870         return err;
 871
 872 out_mknod_dput:
 873         dput(dentry);
 874 out_mknod_unlock:
 875         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 876         path_put(&nd.path);
 877 out_mknod_parent:
 878         if (err==-EEXIST)
 879                 err=-EADDRINUSE;
 880         unix_release_addr(addr);
 881         goto out_up;
 882 }
 883
 884 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
 885 {
 886         if (unlikely(sk1 == sk2) || !sk2) {
 887                 unix_state_lock(sk1);
 888                 return;
 889         }
 890         if (sk1 < sk2) {
 891                 unix_state_lock(sk1);
 892                 unix_state_lock_nested(sk2);
 893         } else {
 894                 unix_state_lock(sk2);
 895                 unix_state_lock_nested(sk1);
 896         }
 897 }
 898
 899 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
 900 {
 901         if (unlikely(sk1 == sk2) || !sk2) {
 902                 unix_state_unlock(sk1);
 903                 return;
 904         }
 905         unix_state_unlock(sk1);
 906         unix_state_unlock(sk2);
 907 }
 908
 909 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 910                               int alen, int flags)
 911 {
 912         struct sock *sk = sock->sk;
 913         struct net *net = sock_net(sk);
 914         struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr;
 915         struct sock *other;
 916         unsigned hash;
 917         int err;
 918
 919         if (addr->sa_family != AF_UNSPEC) {
 920                 err = unix_mkname(sunaddr, alen, &hash);
 921                 if (err < 0)
 922                         goto out;
 923                 alen = err;
 924
 925                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
 926                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
 927                         goto out;
 928
 929 restart:
 930                 other=unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
 931                 if (!other)
 932                         goto out;
 933
 934                 unix_state_double_lock(sk, other);
 935
 936                 /* Apparently VFS overslept socket death. Retry. */
 937                 if (sock_flag(other, SOCK_DEAD)) {
 938                         unix_state_double_unlock(sk, other);
 939                         sock_put(other);
 940                         goto restart;
 941                 }
 942
 943                 err = -EPERM;
 944                 if (!unix_may_send(sk, other))
 945                         goto out_unlock;
 946
 947                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
 948                 if (err)
 949                         goto out_unlock;
 950
 951         } else {
 952                 /*
 953                  *      1003.1g breaking connected state with AF_UNSPEC
 954                  */
 955                 other = NULL;
 956                 unix_state_double_lock(sk, other);
 957         }
 958
 959         /*
 960          * If it was connected, reconnect.
 961          */
 962         if (unix_peer(sk)) {
 963                 struct sock *old_peer = unix_peer(sk);
 964                 unix_peer(sk)=other;
 965                 unix_state_double_unlock(sk, other);
 966
 967                 if (other != old_peer)
 968                         unix_dgram_disconnected(sk, old_peer);
 969                 sock_put(old_peer);
 970         } else {
 971                 unix_peer(sk)=other;
 972                 unix_state_double_unlock(sk, other);
 973         }
 974         return 0;
 975
 976 out_unlock:
 977         unix_state_double_unlock(sk, other);
 978         sock_put(other);
 979 out:
 980         return err;
 981 }
 982
 983 static long unix_wait_for_peer(struct sock *other, long timeo)
 984 {
 985         struct unix_sock *u = unix_sk(other);
 986         int sched;
 987         DEFINE_WAIT(wait);
 988
 989         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
 990
 991         sched = !sock_flag(other, SOCK_DEAD) &&
 992                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
 993                 unix_recvq_full(other);
 994
 995         unix_state_unlock(other);
 996
 997         if (sched)
 998                 timeo = schedule_timeout(timeo);
 999
1000         finish_wait(&u->peer_wait, &wait);
1001         return timeo;
1002 }
1003
1004 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1005                                int addr_len, int flags)
1006 {
1007         struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1008         struct sock *sk = sock->sk;
1009         struct net *net = sock_net(sk);
1010         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1011         struct sock *newsk = NULL;
1012         struct sock *other = NULL;
1013         struct sk_buff *skb = NULL;
1014         unsigned hash;
1015         int st;
1016         int err;
1017         long timeo;
1018
1019         err = unix_mkname(sunaddr, addr_len, &hash);
1020         if (err < 0)
1021                 goto out;
1022         addr_len = err;
1023
1024         if (test_bit(SOCK_PASSCRED, &sock->flags)
1025                 && !u->addr && (err = unix_autobind(sock)) != 0)
1026                 goto out;
1027
1028         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1029
1030         /* First of all allocate resources.
1031            If we will make it after state is locked,
1032            we will have to recheck all again in any case.
1033          */
1034
1035         err = -ENOMEM;
1036
1037         /* create new sock for complete connection */
1038         newsk = unix_create1(sock_net(sk), NULL);
1039         if (newsk == NULL)
1040                 goto out;
1041
1042         /* Allocate skb for sending to listening sock */
1043         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1044         if (skb == NULL)
1045                 goto out;
1046
1047 restart:
1048         /*  Find listening sock. */
1049         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1050         if (!other)
1051                 goto out;
1052
1053         /* Latch state of peer */
1054         unix_state_lock(other);
1055
1056         /* Apparently VFS overslept socket death. Retry. */
1057         if (sock_flag(other, SOCK_DEAD)) {
1058                 unix_state_unlock(other);
1059                 sock_put(other);
1060                 goto restart;
1061         }
1062
1063         err = -ECONNREFUSED;
1064         if (other->sk_state != TCP_LISTEN)
1065                 goto out_unlock;
1066
1067         if (unix_recvq_full(other)) {
1068                 err = -EAGAIN;
1069                 if (!timeo)
1070                         goto out_unlock;
1071
1072                 timeo = unix_wait_for_peer(other, timeo);
1073
1074                 err = sock_intr_errno(timeo);
1075                 if (signal_pending(current))
1076                         goto out;
1077                 sock_put(other);
1078                 goto restart;
1079         }
1080
1081         /* Latch our state.
1082
1083            It is tricky place. We need to grab write lock and cannot
1084            drop lock on peer. It is dangerous because deadlock is
1085            possible. Connect to self case and simultaneous
1086            attempt to connect are eliminated by checking socket
1087            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1088            check this before attempt to grab lock.
1089
1090            Well, and we have to recheck the state after socket locked.
1091          */
1092         st = sk->sk_state;
1093
1094         switch (st) {
1095         case TCP_CLOSE:
1096                 /* This is ok... continue with connect */
1097                 break;
1098         case TCP_ESTABLISHED:
1099                 /* Socket is already connected */
1100                 err = -EISCONN;
1101                 goto out_unlock;
1102         default:
1103                 err = -EINVAL;
1104                 goto out_unlock;
1105         }
1106
1107         unix_state_lock_nested(sk);
1108
1109         if (sk->sk_state != st) {
1110                 unix_state_unlock(sk);
1111                 unix_state_unlock(other);
1112                 sock_put(other);
1113                 goto restart;
1114         }
1115
1116         err = security_unix_stream_connect(sock, other->sk_socket, newsk);
1117         if (err) {
1118                 unix_state_unlock(sk);
1119                 goto out_unlock;
1120         }
1121
1122         /* The way is open! Fastly set all the necessary fields... */
1123
1124         sock_hold(sk);
1125         unix_peer(newsk)        = sk;
1126         newsk->sk_state         = TCP_ESTABLISHED;
1127         newsk->sk_type          = sk->sk_type;
1128         newsk->sk_peercred.pid  = task_tgid_vnr(current);
1129         newsk->sk_peercred.uid  = current->euid;
1130         newsk->sk_peercred.gid  = current->egid;
1131         newu = unix_sk(newsk);
1132         newsk->sk_sleep         = &newu->peer_wait;
1133         otheru = unix_sk(other);
1134
1135         /* copy address information from listening to new sock*/
1136         if (otheru->addr) {
1137                 atomic_inc(&otheru->addr->refcnt);
1138                 newu->addr = otheru->addr;
1139         }
1140         if (otheru->dentry) {
1141                 newu->dentry    = dget(otheru->dentry);
1142                 newu->mnt       = mntget(otheru->mnt);
1143         }
1144
1145         /* Set credentials */
1146         sk->sk_peercred = other->sk_peercred;
1147
1148         sock->state     = SS_CONNECTED;
1149         sk->sk_state    = TCP_ESTABLISHED;
1150         sock_hold(newsk);
1151
1152         smp_mb__after_atomic_inc();     /* sock_hold() does an atomic_inc() */
1153         unix_peer(sk)   = newsk;
1154
1155         unix_state_unlock(sk);
1156
1157         /* take ten and and send info to listening sock */
1158         spin_lock(&other->sk_receive_queue.lock);
1159         __skb_queue_tail(&other->sk_receive_queue, skb);
1160         spin_unlock(&other->sk_receive_queue.lock);
1161         unix_state_unlock(other);
1162         other->sk_data_ready(other, 0);
1163         sock_put(other);
1164         return 0;
1165
1166 out_unlock:
1167         if (other)
1168                 unix_state_unlock(other);
1169
1170 out:
1171         if (skb)
1172                 kfree_skb(skb);
1173         if (newsk)
1174                 unix_release_sock(newsk, 0);
1175         if (other)
1176                 sock_put(other);
1177         return err;
1178 }
1179
1180 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1181 {
1182         struct sock *ska=socka->sk, *skb = sockb->sk;
1183
1184         /* Join our sockets back to back */
1185         sock_hold(ska);
1186         sock_hold(skb);
1187         unix_peer(ska)=skb;
1188         unix_peer(skb)=ska;
1189         ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
1190         ska->sk_peercred.uid = skb->sk_peercred.uid = current->euid;
1191         ska->sk_peercred.gid = skb->sk_peercred.gid = current->egid;
1192
1193         if (ska->sk_type != SOCK_DGRAM) {
1194                 ska->sk_state = TCP_ESTABLISHED;
1195                 skb->sk_state = TCP_ESTABLISHED;
1196                 socka->state  = SS_CONNECTED;
1197                 sockb->state  = SS_CONNECTED;
1198         }
1199         return 0;
1200 }
1201
1202 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1203 {
1204         struct sock *sk = sock->sk;
1205         struct sock *tsk;
1206         struct sk_buff *skb;
1207         int err;
1208
1209         err = -EOPNOTSUPP;
1210         if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET)
1211                 goto out;
1212
1213         err = -EINVAL;
1214         if (sk->sk_state != TCP_LISTEN)
1215                 goto out;
1216
1217         /* If socket state is TCP_LISTEN it cannot change (for now...),
1218          * so that no locks are necessary.
1219          */
1220
1221         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1222         if (!skb) {
1223                 /* This means receive shutdown. */
1224                 if (err == 0)
1225                         err = -EINVAL;
1226                 goto out;
1227         }
1228
1229         tsk = skb->sk;
1230         skb_free_datagram(sk, skb);
1231         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1232
1233         /* attach accepted sock to socket */
1234         unix_state_lock(tsk);
1235         newsock->state = SS_CONNECTED;
1236         sock_graft(tsk, newsock);
1237         unix_state_unlock(tsk);
1238         return 0;
1239
1240 out:
1241         return err;
1242 }
1243
1244
1245 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1246 {
1247         struct sock *sk = sock->sk;
1248         struct unix_sock *u;
1249         struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
1250         int err = 0;
1251
1252         if (peer) {
1253                 sk = unix_peer_get(sk);
1254
1255                 err = -ENOTCONN;
1256                 if (!sk)
1257                         goto out;
1258                 err = 0;
1259         } else {
1260                 sock_hold(sk);
1261         }
1262
1263         u = unix_sk(sk);
1264         unix_state_lock(sk);
1265         if (!u->addr) {
1266                 sunaddr->sun_family = AF_UNIX;
1267                 sunaddr->sun_path[0] = 0;
1268                 *uaddr_len = sizeof(short);
1269         } else {
1270                 struct unix_address *addr = u->addr;
1271
1272                 *uaddr_len = addr->len;
1273                 memcpy(sunaddr, addr->name, *uaddr_len);
1274         }
1275         unix_state_unlock(sk);
1276         sock_put(sk);
1277 out:
1278         return err;
1279 }
1280
1281 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1282 {
1283         int i;
1284
1285         scm->fp = UNIXCB(skb).fp;
1286         skb->destructor = sock_wfree;
1287         UNIXCB(skb).fp = NULL;
1288
1289         for (i=scm->fp->count-1; i>=0; i--)
1290                 unix_notinflight(scm->fp->fp[i]);
1291 }
1292
1293 static void unix_destruct_fds(struct sk_buff *skb)
1294 {
1295         struct scm_cookie scm;
1296         memset(&scm, 0, sizeof(scm));
1297         unix_detach_fds(&scm, skb);
1298
1299         /* Alas, it calls VFS */
1300         /* So fscking what? fput() had been SMP-safe since the last Summer */
1301         scm_destroy(&scm);
1302         sock_wfree(skb);
1303 }
1304
1305 static void unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1306 {
1307         int i;
1308         for (i=scm->fp->count-1; i>=0; i--)
1309                 unix_inflight(scm->fp->fp[i]);
1310         UNIXCB(skb).fp = scm->fp;
1311         skb->destructor = unix_destruct_fds;
1312         scm->fp = NULL;
1313 }
1314
1315 /*
1316  *      Send AF_UNIX data.
1317  */
1318
1319 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1320                               struct msghdr *msg, size_t len)
1321 {
1322         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1323         struct sock *sk = sock->sk;
1324         struct net *net = sock_net(sk);
1325         struct unix_sock *u = unix_sk(sk);
1326         struct sockaddr_un *sunaddr=msg->msg_name;
1327         struct sock *other = NULL;
1328         int namelen = 0; /* fake GCC */
1329         int err;
1330         unsigned hash;
1331         struct sk_buff *skb;
1332         long timeo;
1333         struct scm_cookie tmp_scm;
1334
1335         if (NULL == siocb->scm)
1336                 siocb->scm = &tmp_scm;
1337         err = scm_send(sock, msg, siocb->scm);
1338         if (err < 0)
1339                 return err;
1340
1341         err = -EOPNOTSUPP;
1342         if (msg->msg_flags&MSG_OOB)
1343                 goto out;
1344
1345         if (msg->msg_namelen) {
1346                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1347                 if (err < 0)
1348                         goto out;
1349                 namelen = err;
1350         } else {
1351                 sunaddr = NULL;
1352                 err = -ENOTCONN;
1353                 other = unix_peer_get(sk);
1354                 if (!other)
1355                         goto out;
1356         }
1357
1358         if (test_bit(SOCK_PASSCRED, &sock->flags)
1359                 && !u->addr && (err = unix_autobind(sock)) != 0)
1360                 goto out;
1361
1362         err = -EMSGSIZE;
1363         if (len > sk->sk_sndbuf - 32)
1364                 goto out;
1365
1366         skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1367         if (skb==NULL)
1368                 goto out;
1369
1370         memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1371         if (siocb->scm->fp)
1372                 unix_attach_fds(siocb->scm, skb);
1373         unix_get_secdata(siocb->scm, skb);
1374
1375         skb_reset_transport_header(skb);
1376         err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
1377         if (err)
1378                 goto out_free;
1379
1380         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1381
1382 restart:
1383         if (!other) {
1384                 err = -ECONNRESET;
1385                 if (sunaddr == NULL)
1386                         goto out_free;
1387
1388                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1389                                         hash, &err);
1390                 if (other==NULL)
1391                         goto out_free;
1392         }
1393
1394         unix_state_lock(other);
1395         err = -EPERM;
1396         if (!unix_may_send(sk, other))
1397                 goto out_unlock;
1398
1399         if (sock_flag(other, SOCK_DEAD)) {
1400                 /*
1401                  *      Check with 1003.1g - what should
1402                  *      datagram error
1403                  */
1404                 unix_state_unlock(other);
1405                 sock_put(other);
1406
1407                 err = 0;
1408                 unix_state_lock(sk);
1409                 if (unix_peer(sk) == other) {
1410                         unix_peer(sk)=NULL;
1411                         unix_state_unlock(sk);
1412
1413                         unix_dgram_disconnected(sk, other);
1414                         sock_put(other);
1415                         err = -ECONNREFUSED;
1416                 } else {
1417                         unix_state_unlock(sk);
1418                 }
1419
1420                 other = NULL;
1421                 if (err)
1422                         goto out_free;
1423                 goto restart;
1424         }
1425
1426         err = -EPIPE;
1427         if (other->sk_shutdown & RCV_SHUTDOWN)
1428                 goto out_unlock;
1429
1430         if (sk->sk_type != SOCK_SEQPACKET) {
1431                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1432                 if (err)
1433                         goto out_unlock;
1434         }
1435
1436         if (unix_peer(other) != sk && unix_recvq_full(other)) {
1437                 if (!timeo) {
1438                         err = -EAGAIN;
1439                         goto out_unlock;
1440                 }
1441
1442                 timeo = unix_wait_for_peer(other, timeo);
1443
1444                 err = sock_intr_errno(timeo);
1445                 if (signal_pending(current))
1446                         goto out_free;
1447
1448                 goto restart;
1449         }
1450
1451         skb_queue_tail(&other->sk_receive_queue, skb);
1452         unix_state_unlock(other);
1453         other->sk_data_ready(other, len);
1454         sock_put(other);
1455         scm_destroy(siocb->scm);
1456         return len;
1457
1458 out_unlock:
1459         unix_state_unlock(other);
1460 out_free:
1461         kfree_skb(skb);
1462 out:
1463         if (other)
1464                 sock_put(other);
1465         scm_destroy(siocb->scm);
1466         return err;
1467 }
1468
1469
1470 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1471                                struct msghdr *msg, size_t len)
1472 {
1473         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1474         struct sock *sk = sock->sk;
1475         struct sock *other = NULL;
1476         struct sockaddr_un *sunaddr=msg->msg_name;
1477         int err,size;
1478         struct sk_buff *skb;
1479         int sent=0;
1480         struct scm_cookie tmp_scm;
1481
1482         if (NULL == siocb->scm)
1483                 siocb->scm = &tmp_scm;
1484         err = scm_send(sock, msg, siocb->scm);
1485         if (err < 0)
1486                 return err;
1487
1488         err = -EOPNOTSUPP;
1489         if (msg->msg_flags&MSG_OOB)
1490                 goto out_err;
1491
1492         if (msg->msg_namelen) {
1493                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1494                 goto out_err;
1495         } else {
1496                 sunaddr = NULL;
1497                 err = -ENOTCONN;
1498                 other = unix_peer(sk);
1499                 if (!other)
1500                         goto out_err;
1501         }
1502
1503         if (sk->sk_shutdown & SEND_SHUTDOWN)
1504                 goto pipe_err;
1505
1506         while(sent < len)
1507         {
1508                 /*
1509                  *      Optimisation for the fact that under 0.01% of X
1510                  *      messages typically need breaking up.
1511                  */
1512
1513                 size = len-sent;
1514
1515                 /* Keep two messages in the pipe so it schedules better */
1516                 if (size > ((sk->sk_sndbuf >> 1) - 64))
1517                         size = (sk->sk_sndbuf >> 1) - 64;
1518
1519                 if (size > SKB_MAX_ALLOC)
1520                         size = SKB_MAX_ALLOC;
1521
1522                 /*
1523                  *      Grab a buffer
1524                  */
1525
1526                 skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err);
1527
1528                 if (skb==NULL)
1529                         goto out_err;
1530
1531                 /*
1532                  *      If you pass two values to the sock_alloc_send_skb
1533                  *      it tries to grab the large buffer with GFP_NOFS
1534                  *      (which can fail easily), and if it fails grab the
1535                  *      fallback size buffer which is under a page and will
1536                  *      succeed. [Alan]
1537                  */
1538                 size = min_t(int, size, skb_tailroom(skb));
1539
1540                 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1541                 if (siocb->scm->fp)
1542                         unix_attach_fds(siocb->scm, skb);
1543
1544                 if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) {
1545                         kfree_skb(skb);
1546                         goto out_err;
1547                 }
1548
1549                 unix_state_lock(other);
1550
1551                 if (sock_flag(other, SOCK_DEAD) ||
1552                     (other->sk_shutdown & RCV_SHUTDOWN))
1553                         goto pipe_err_free;
1554
1555                 skb_queue_tail(&other->sk_receive_queue, skb);
1556                 unix_state_unlock(other);
1557                 other->sk_data_ready(other, size);
1558                 sent+=size;
1559         }
1560
1561         scm_destroy(siocb->scm);
1562         siocb->scm = NULL;
1563
1564         return sent;
1565
1566 pipe_err_free:
1567         unix_state_unlock(other);
1568         kfree_skb(skb);
1569 pipe_err:
1570         if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL))
1571                 send_sig(SIGPIPE,current,0);
1572         err = -EPIPE;
1573 out_err:
1574         scm_destroy(siocb->scm);
1575         siocb->scm = NULL;
1576         return sent ? : err;
1577 }
1578
1579 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1580                                   struct msghdr *msg, size_t len)
1581 {
1582         int err;
1583         struct sock *sk = sock->sk;
1584
1585         err = sock_error(sk);
1586         if (err)
1587                 return err;
1588
1589         if (sk->sk_state != TCP_ESTABLISHED)
1590                 return -ENOTCONN;
1591
1592         if (msg->msg_namelen)
1593                 msg->msg_namelen = 0;
1594
1595         return unix_dgram_sendmsg(kiocb, sock, msg, len);
1596 }
1597
1598 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1599 {
1600         struct unix_sock *u = unix_sk(sk);
1601
1602         msg->msg_namelen = 0;
1603         if (u->addr) {
1604                 msg->msg_namelen = u->addr->len;
1605                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1606         }
1607 }
1608
1609 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1610                               struct msghdr *msg, size_t size,
1611                               int flags)
1612 {
1613         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1614         struct scm_cookie tmp_scm;
1615         struct sock *sk = sock->sk;
1616         struct unix_sock *u = unix_sk(sk);
1617         int noblock = flags & MSG_DONTWAIT;
1618         struct sk_buff *skb;
1619         int err;
1620
1621         err = -EOPNOTSUPP;
1622         if (flags&MSG_OOB)
1623                 goto out;
1624
1625         msg->msg_namelen = 0;
1626
1627         mutex_lock(&u->readlock);
1628
1629         skb = skb_recv_datagram(sk, flags, noblock, &err);
1630         if (!skb) {
1631                 unix_state_lock(sk);
1632                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1633                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1634                     (sk->sk_shutdown & RCV_SHUTDOWN))
1635                         err = 0;
1636                 unix_state_unlock(sk);
1637                 goto out_unlock;
1638         }
1639
1640         wake_up_interruptible_sync(&u->peer_wait);
1641
1642         if (msg->msg_name)
1643                 unix_copy_addr(msg, skb->sk);
1644
1645         if (size > skb->len)
1646                 size = skb->len;
1647         else if (size < skb->len)
1648                 msg->msg_flags |= MSG_TRUNC;
1649
1650         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1651         if (err)
1652                 goto out_free;
1653
1654         if (!siocb->scm) {
1655                 siocb->scm = &tmp_scm;
1656                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1657         }
1658         siocb->scm->creds = *UNIXCREDS(skb);
1659         unix_set_secdata(siocb->scm, skb);
1660
1661         if (!(flags & MSG_PEEK))
1662         {
1663                 if (UNIXCB(skb).fp)
1664                         unix_detach_fds(siocb->scm, skb);
1665         }
1666         else
1667         {
1668                 /* It is questionable: on PEEK we could:
1669                    - do not return fds - good, but too simple 8)
1670                    - return fds, and do not return them on read (old strategy,
1671                      apparently wrong)
1672                    - clone fds (I chose it for now, it is the most universal
1673                      solution)
1674
1675                    POSIX 1003.1g does not actually define this clearly
1676                    at all. POSIX 1003.1g doesn't define a lot of things
1677                    clearly however!
1678
1679                 */
1680                 if (UNIXCB(skb).fp)
1681                         siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1682         }
1683         err = size;
1684
1685         scm_recv(sock, msg, siocb->scm, flags);
1686
1687 out_free:
1688         skb_free_datagram(sk,skb);
1689 out_unlock:
1690         mutex_unlock(&u->readlock);
1691 out:
1692         return err;
1693 }
1694
1695 /*
1696  *      Sleep until data has arrive. But check for races..
1697  */
1698
1699 static long unix_stream_data_wait(struct sock * sk, long timeo)
1700 {
1701         DEFINE_WAIT(wait);
1702
1703         unix_state_lock(sk);
1704
1705         for (;;) {
1706                 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
1707
1708                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1709                     sk->sk_err ||
1710                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
1711                     signal_pending(current) ||
1712                     !timeo)
1713                         break;
1714
1715                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1716                 unix_state_unlock(sk);
1717                 timeo = schedule_timeout(timeo);
1718                 unix_state_lock(sk);
1719                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1720         }
1721
1722         finish_wait(sk->sk_sleep, &wait);
1723         unix_state_unlock(sk);
1724         return timeo;
1725 }
1726
1727
1728
1729 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1730                                struct msghdr *msg, size_t size,
1731                                int flags)
1732 {
1733         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1734         struct scm_cookie tmp_scm;
1735         struct sock *sk = sock->sk;
1736         struct unix_sock *u = unix_sk(sk);
1737         struct sockaddr_un *sunaddr=msg->msg_name;
1738         int copied = 0;
1739         int check_creds = 0;
1740         int target;
1741         int err = 0;
1742         long timeo;
1743
1744         err = -EINVAL;
1745         if (sk->sk_state != TCP_ESTABLISHED)
1746                 goto out;
1747
1748         err = -EOPNOTSUPP;
1749         if (flags&MSG_OOB)
1750                 goto out;
1751
1752         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1753         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1754
1755         msg->msg_namelen = 0;
1756
1757         /* Lock the socket to prevent queue disordering
1758          * while sleeps in memcpy_tomsg
1759          */
1760
1761         if (!siocb->scm) {
1762                 siocb->scm = &tmp_scm;
1763                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1764         }
1765
1766         mutex_lock(&u->readlock);
1767
1768         do
1769         {
1770                 int chunk;
1771                 struct sk_buff *skb;
1772
1773                 unix_state_lock(sk);
1774                 skb = skb_dequeue(&sk->sk_receive_queue);
1775                 if (skb==NULL)
1776                 {
1777                         if (copied >= target)
1778                                 goto unlock;
1779
1780                         /*
1781                          *      POSIX 1003.1g mandates this order.
1782                          */
1783
1784                         if ((err = sock_error(sk)) != 0)
1785                                 goto unlock;
1786                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1787                                 goto unlock;
1788
1789                         unix_state_unlock(sk);
1790                         err = -EAGAIN;
1791                         if (!timeo)
1792                                 break;
1793                         mutex_unlock(&u->readlock);
1794
1795                         timeo = unix_stream_data_wait(sk, timeo);
1796
1797                         if (signal_pending(current)) {
1798                                 err = sock_intr_errno(timeo);
1799                                 goto out;
1800                         }
1801                         mutex_lock(&u->readlock);
1802                         continue;
1803  unlock:
1804                         unix_state_unlock(sk);
1805                         break;
1806                 }
1807                 unix_state_unlock(sk);
1808
1809                 if (check_creds) {
1810                         /* Never glue messages from different writers */
1811                         if (memcmp(UNIXCREDS(skb), &siocb->scm->creds, sizeof(siocb->scm->creds)) != 0) {
1812                                 skb_queue_head(&sk->sk_receive_queue, skb);
1813                                 break;
1814                         }
1815                 } else {
1816                         /* Copy credentials */
1817                         siocb->scm->creds = *UNIXCREDS(skb);
1818                         check_creds = 1;
1819                 }
1820
1821                 /* Copy address just once */
1822                 if (sunaddr)
1823                 {
1824                         unix_copy_addr(msg, skb->sk);
1825                         sunaddr = NULL;
1826                 }
1827
1828                 chunk = min_t(unsigned int, skb->len, size);
1829                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1830                         skb_queue_head(&sk->sk_receive_queue, skb);
1831                         if (copied == 0)
1832                                 copied = -EFAULT;
1833                         break;
1834                 }
1835                 copied += chunk;
1836                 size -= chunk;
1837
1838                 /* Mark read part of skb as used */
1839                 if (!(flags & MSG_PEEK))
1840                 {
1841                         skb_pull(skb, chunk);
1842
1843                         if (UNIXCB(skb).fp)
1844                                 unix_detach_fds(siocb->scm, skb);
1845
1846                         /* put the skb back if we didn't use it up.. */
1847                         if (skb->len)
1848                         {
1849                                 skb_queue_head(&sk->sk_receive_queue, skb);
1850                                 break;
1851                         }
1852
1853                         kfree_skb(skb);
1854
1855                         if (siocb->scm->fp)
1856                                 break;
1857                 }
1858                 else
1859                 {
1860                         /* It is questionable, see note in unix_dgram_recvmsg.
1861                          */
1862                         if (UNIXCB(skb).fp)
1863                                 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1864
1865                         /* put message back and return */
1866                         skb_queue_head(&sk->sk_receive_queue, skb);
1867                         break;
1868                 }
1869         } while (size);
1870
1871         mutex_unlock(&u->readlock);
1872         scm_recv(sock, msg, siocb->scm, flags);
1873 out:
1874         return copied ? : err;
1875 }
1876
1877 static int unix_shutdown(struct socket *sock, int mode)
1878 {
1879         struct sock *sk = sock->sk;
1880         struct sock *other;
1881
1882         mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1883
1884         if (mode) {
1885                 unix_state_lock(sk);
1886                 sk->sk_shutdown |= mode;
1887                 other=unix_peer(sk);
1888                 if (other)
1889                         sock_hold(other);
1890                 unix_state_unlock(sk);
1891                 sk->sk_state_change(sk);
1892
1893                 if (other &&
1894                         (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
1895
1896                         int peer_mode = 0;
1897
1898                         if (mode&RCV_SHUTDOWN)
1899                                 peer_mode |= SEND_SHUTDOWN;
1900                         if (mode&SEND_SHUTDOWN)
1901                                 peer_mode |= RCV_SHUTDOWN;
1902                         unix_state_lock(other);
1903                         other->sk_shutdown |= peer_mode;
1904                         unix_state_unlock(other);
1905                         other->sk_state_change(other);
1906                         read_lock(&other->sk_callback_lock);
1907                         if (peer_mode == SHUTDOWN_MASK)
1908                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
1909                         else if (peer_mode & RCV_SHUTDOWN)
1910                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
1911                         read_unlock(&other->sk_callback_lock);
1912                 }
1913                 if (other)
1914                         sock_put(other);
1915         }
1916         return 0;
1917 }
1918
1919 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1920 {
1921         struct sock *sk = sock->sk;
1922         long amount=0;
1923         int err;
1924
1925         switch(cmd)
1926         {
1927                 case SIOCOUTQ:
1928                         amount = atomic_read(&sk->sk_wmem_alloc);
1929                         err = put_user(amount, (int __user *)arg);
1930                         break;
1931                 case SIOCINQ:
1932                 {
1933                         struct sk_buff *skb;
1934
1935                         if (sk->sk_state == TCP_LISTEN) {
1936                                 err = -EINVAL;
1937                                 break;
1938                         }
1939
1940                         spin_lock(&sk->sk_receive_queue.lock);
1941                         if (sk->sk_type == SOCK_STREAM ||
1942                             sk->sk_type == SOCK_SEQPACKET) {
1943                                 skb_queue_walk(&sk->sk_receive_queue, skb)
1944                                         amount += skb->len;
1945                         } else {
1946                                 skb = skb_peek(&sk->sk_receive_queue);
1947                                 if (skb)
1948                                         amount=skb->len;
1949                         }
1950                         spin_unlock(&sk->sk_receive_queue.lock);
1951                         err = put_user(amount, (int __user *)arg);
1952                         break;
1953                 }
1954
1955                 default:
1956                         err = -ENOIOCTLCMD;
1957                         break;
1958         }
1959         return err;
1960 }
1961
1962 static unsigned int unix_poll(struct file * file, struct socket *sock, poll_table *wait)
1963 {
1964         struct sock *sk = sock->sk;
1965         unsigned int mask;
1966
1967         poll_wait(file, sk->sk_sleep, wait);
1968         mask = 0;
1969
1970         /* exceptional events? */
1971         if (sk->sk_err)
1972                 mask |= POLLERR;
1973         if (sk->sk_shutdown == SHUTDOWN_MASK)
1974                 mask |= POLLHUP;
1975         if (sk->sk_shutdown & RCV_SHUTDOWN)
1976                 mask |= POLLRDHUP;
1977
1978         /* readable? */
1979         if (!skb_queue_empty(&sk->sk_receive_queue) ||
1980             (sk->sk_shutdown & RCV_SHUTDOWN))
1981                 mask |= POLLIN | POLLRDNORM;
1982
1983         /* Connection-based need to check for termination and startup */
1984         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && sk->sk_state == TCP_CLOSE)
1985                 mask |= POLLHUP;
1986
1987         /*
1988          * we set writable also when the other side has shut down the
1989          * connection. This prevents stuck sockets.
1990          */
1991         if (unix_writable(sk))
1992                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
1993
1994         return mask;
1995 }
1996
1997 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
1998                                     poll_table *wait)
1999 {
2000         struct sock *sk = sock->sk, *other;
2001         unsigned int mask, writable;
2002
2003         poll_wait(file, sk->sk_sleep, wait);
2004         mask = 0;
2005
2006         /* exceptional events? */
2007         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2008                 mask |= POLLERR;
2009         if (sk->sk_shutdown & RCV_SHUTDOWN)
2010                 mask |= POLLRDHUP;
2011         if (sk->sk_shutdown == SHUTDOWN_MASK)
2012                 mask |= POLLHUP;
2013
2014         /* readable? */
2015         if (!skb_queue_empty(&sk->sk_receive_queue) ||
2016             (sk->sk_shutdown & RCV_SHUTDOWN))
2017                 mask |= POLLIN | POLLRDNORM;
2018
2019         /* Connection-based need to check for termination and startup */
2020         if (sk->sk_type == SOCK_SEQPACKET) {
2021                 if (sk->sk_state == TCP_CLOSE)
2022                         mask |= POLLHUP;
2023                 /* connection hasn't started yet? */
2024                 if (sk->sk_state == TCP_SYN_SENT)
2025                         return mask;
2026         }
2027
2028         /* writable? */
2029         writable = unix_writable(sk);
2030         if (writable) {
2031                 other = unix_peer_get(sk);
2032                 if (other) {
2033                         if (unix_peer(other) != sk) {
2034                                 poll_wait(file, &unix_sk(other)->peer_wait,
2035                                           wait);
2036                                 if (unix_recvq_full(other))
2037                                         writable = 0;
2038                         }
2039
2040                         sock_put(other);
2041                 }
2042         }
2043
2044         if (writable)
2045                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2046         else
2047                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2048
2049         return mask;
2050 }
2051
2052 #ifdef CONFIG_PROC_FS
2053 static struct sock *first_unix_socket(int *i)
2054 {
2055         for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2056                 if (!hlist_empty(&unix_socket_table[*i]))
2057                         return __sk_head(&unix_socket_table[*i]);
2058         }
2059         return NULL;
2060 }
2061
2062 static struct sock *next_unix_socket(int *i, struct sock *s)
2063 {
2064         struct sock *next = sk_next(s);
2065         /* More in this chain? */
2066         if (next)
2067                 return next;
2068         /* Look for next non-empty chain. */
2069         for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2070                 if (!hlist_empty(&unix_socket_table[*i]))
2071                         return __sk_head(&unix_socket_table[*i]);
2072         }
2073         return NULL;
2074 }
2075
2076 struct unix_iter_state {
2077         struct seq_net_private p;
2078         int i;
2079 };
2080 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2081 {
2082         struct unix_iter_state *iter = seq->private;
2083         loff_t off = 0;
2084         struct sock *s;
2085
2086         for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2087                 if (sock_net(s) != seq_file_net(seq))
2088                         continue;
2089                 if (off == pos)
2090                         return s;
2091                 ++off;
2092         }
2093         return NULL;
2094 }
2095
2096
2097 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2098         __acquires(unix_table_lock)
2099 {
2100         spin_lock(&unix_table_lock);
2101         return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2102 }
2103
2104 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2105 {
2106         struct unix_iter_state *iter = seq->private;
2107         struct sock *sk = v;
2108         ++*pos;
2109
2110         if (v == SEQ_START_TOKEN)
2111                 sk = first_unix_socket(&iter->i);
2112         else
2113                 sk = next_unix_socket(&iter->i, sk);
2114         while (sk && (sock_net(sk) != seq_file_net(seq)))
2115                 sk = next_unix_socket(&iter->i, sk);
2116         return sk;
2117 }
2118
2119 static void unix_seq_stop(struct seq_file *seq, void *v)
2120         __releases(unix_table_lock)
2121 {
2122         spin_unlock(&unix_table_lock);
2123 }
2124
2125 static int unix_seq_show(struct seq_file *seq, void *v)
2126 {
2127
2128         if (v == SEQ_START_TOKEN)
2129                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2130                          "Inode Path\n");
2131         else {
2132                 struct sock *s = v;
2133                 struct unix_sock *u = unix_sk(s);
2134                 unix_state_lock(s);
2135
2136                 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2137                         s,
2138                         atomic_read(&s->sk_refcnt),
2139                         0,
2140                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2141                         s->sk_type,
2142                         s->sk_socket ?
2143                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2144                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2145                         sock_i_ino(s));
2146
2147                 if (u->addr) {
2148                         int i, len;
2149                         seq_putc(seq, ' ');
2150
2151                         i = 0;
2152                         len = u->addr->len - sizeof(short);
2153                         if (!UNIX_ABSTRACT(s))
2154                                 len--;
2155                         else {
2156                                 seq_putc(seq, '@');
2157                                 i++;
2158                         }
2159                         for ( ; i < len; i++)
2160                                 seq_putc(seq, u->addr->name->sun_path[i]);
2161                 }
2162                 unix_state_unlock(s);
2163                 seq_putc(seq, '\n');
2164         }
2165
2166         return 0;
2167 }
2168
2169 static const struct seq_operations unix_seq_ops = {
2170         .start  = unix_seq_start,
2171         .next   = unix_seq_next,
2172         .stop   = unix_seq_stop,
2173         .show   = unix_seq_show,
2174 };
2175
2176
2177 static int unix_seq_open(struct inode *inode, struct file *file)
2178 {
2179         return seq_open_net(inode, file, &unix_seq_ops,
2180                             sizeof(struct unix_iter_state));
2181 }
2182
2183 static const struct file_operations unix_seq_fops = {
2184         .owner          = THIS_MODULE,
2185         .open           = unix_seq_open,
2186         .read           = seq_read,
2187         .llseek         = seq_lseek,
2188         .release        = seq_release_net,
2189 };
2190
2191 #endif
2192
2193 static struct net_proto_family unix_family_ops = {
2194         .family = PF_UNIX,
2195         .create = unix_create,
2196         .owner  = THIS_MODULE,
2197 };
2198
2199
2200 static int unix_net_init(struct net *net)
2201 {
2202         int error = -ENOMEM;
2203
2204         net->unx.sysctl_max_dgram_qlen = 10;
2205         if (unix_sysctl_register(net))
2206                 goto out;
2207
2208 #ifdef CONFIG_PROC_FS
2209         if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2210                 unix_sysctl_unregister(net);
2211                 goto out;
2212         }
2213 #endif
2214         error = 0;
2215 out:
2216         return 0;
2217 }
2218
2219 static void unix_net_exit(struct net *net)
2220 {
2221         unix_sysctl_unregister(net);
2222         proc_net_remove(net, "unix");
2223 }
2224
2225 static struct pernet_operations unix_net_ops = {
2226         .init = unix_net_init,
2227         .exit = unix_net_exit,
2228 };
2229
2230 static int __init af_unix_init(void)
2231 {
2232         int rc = -1;
2233         struct sk_buff *dummy_skb;
2234
2235         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2236
2237         rc = proto_register(&unix_proto, 1);
2238         if (rc != 0) {
2239                 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2240                        __func__);
2241                 goto out;
2242         }
2243
2244         sock_register(&unix_family_ops);
2245         register_pernet_subsys(&unix_net_ops);
2246 out:
2247         return rc;
2248 }
2249
2250 static void __exit af_unix_exit(void)
2251 {
2252         sock_unregister(PF_UNIX);
2253         proto_unregister(&unix_proto);
2254         unregister_pernet_subsys(&unix_net_ops);
2255 }
2256
2257 /* Earlier than device_initcall() so that other drivers invoking
2258    request_module() don't end up in a loop when modprobe tries
2259    to use a UNIX socket. But later than subsys_initcall() because
2260    we depend on stuff initialised there */
2261 fs_initcall(af_unix_init);
2262 module_exit(af_unix_exit);
2263
2264 MODULE_LICENSE("GPL");
2265 MODULE_ALIAS_NETPROTO(PF_UNIX);