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