net/unix/af_unix.c

   1 /*
   2  * NET4:        Implementation of BSD Unix domain sockets.
   3  *
   4  * Authors:     Alan Cox, <alan@lxorguk.ukuu.org.uk>
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  *
  11  * Fixes:
  12  *              Linus Torvalds  :       Assorted bug cures.
  13  *              Niibe Yutaka    :       async I/O support.
  14  *              Carsten Paeth   :       PF_UNIX check, address fixes.
  15  *              Alan Cox        :       Limit size of allocated blocks.
  16  *              Alan Cox        :       Fixed the stupid socketpair bug.
  17  *              Alan Cox        :       BSD compatibility fine tuning.
  18  *              Alan Cox        :       Fixed a bug in connect when interrupted.
  19  *              Alan Cox        :       Sorted out a proper draft version of
  20  *                                      file descriptor passing hacked up from
  21  *                                      Mike Shaver's work.
  22  *              Marty Leisner   :       Fixes to fd passing
  23  *              Nick Nevin      :       recvmsg bugfix.
  24  *              Alan Cox        :       Started proper garbage collector
  25  *              Heiko EiBfeldt  :       Missing verify_area check
  26  *              Alan Cox        :       Started POSIXisms
  27  *              Andreas Schwab  :       Replace inode by dentry for proper
  28  *                                      reference counting
  29  *              Kirk Petersen   :       Made this a module
  30  *          Christoph Rohland   :       Elegant non-blocking accept/connect algorithm.
  31  *                                      Lots of bug fixes.
  32  *           Alexey Kuznetosv   :       Repaired (I hope) bugs introduces
  33  *                                      by above two patches.
  34  *           Andrea Arcangeli   :       If possible we block in connect(2)
  35  *                                      if the max backlog of the listen socket
  36  *                                      is been reached. This won't break
  37  *                                      old apps and it will avoid huge amount
  38  *                                      of socks hashed (this for unix_gc()
  39  *                                      performances reasons).
  40  *                                      Security fix that limits the max
  41  *                                      number of socks to 2*max_files and
  42  *                                      the number of skb queueable in the
  43  *                                      dgram receiver.
  44  *              Artur Skawina   :       Hash function optimizations
  45  *           Alexey Kuznetsov   :       Full scale SMP. Lot of bugs are introduced 8)
  46  *            Malcolm Beattie   :       Set peercred for socketpair
  47  *           Michal Ostrowski   :       Module initialization cleanup.
  48  *           Arnaldo C. Melo    :       Remove MOD_{INC,DEC}_USE_COUNT,
  49  *                                      the core infrastructure is doing that
  50  *                                      for all net proto families now (2.5.69+)
  51  *
  52  *
  53  * Known differences from reference BSD that was tested:
  54  *
  55  *      [TO FIX]
  56  *      ECONNREFUSED is not returned from one end of a connected() socket to the
  57  *              other the moment one end closes.
  58  *      fstat() doesn't return st_dev=0, and give the blksize as high water mark
  59  *              and a fake inode identifier (nor the BSD first socket fstat twice bug).
  60  *      [NOT TO FIX]
  61  *      accept() returns a path name even if the connecting socket has closed
  62  *              in the meantime (BSD loses the path and gives up).
  63  *      accept() returns 0 length path for an unbound connector. BSD returns 16
  64  *              and a null first byte in the path (but not for gethost/peername - BSD bug ??)
  65  *      socketpair(...SOCK_RAW..) doesn't panic the kernel.
  66  *      BSD af_unix apparently has connect forgetting to block properly.
  67  *              (need to check this with the POSIX spec in detail)
  68  *
  69  * Differences from 2.0.0-11-... (ANK)
  70  *      Bug fixes and improvements.
  71  *              - client shutdown killed server socket.
  72  *              - removed all useless cli/sti pairs.
  73  *
  74  *      Semantic changes/extensions.
  75  *              - generic control message passing.
  76  *              - SCM_CREDENTIALS control message.
  77  *              - "Abstract" (not FS based) socket bindings.
  78  *                Abstract names are sequences of bytes (not zero terminated)
  79  *                started by 0, so that this name space does not intersect
  80  *                with BSD names.
  81  */
  82
  83 #include <linux/module.h>
  84 #include <linux/kernel.h>
  85 #include <linux/signal.h>
  86 #include <linux/sched.h>
  87 #include <linux/errno.h>
  88 #include <linux/string.h>
  89 #include <linux/stat.h>
  90 #include <linux/dcache.h>
  91 #include <linux/namei.h>
  92 #include <linux/socket.h>
  93 #include <linux/un.h>
  94 #include <linux/fcntl.h>
  95 #include <linux/termios.h>
  96 #include <linux/sockios.h>
  97 #include <linux/net.h>
  98 #include <linux/in.h>
  99 #include <linux/fs.h>
 100 #include <linux/slab.h>
 101 #include <asm/uaccess.h>
 102 #include <linux/skbuff.h>
 103 #include <linux/netdevice.h>
 104 #include <net/net_namespace.h>
 105 #include <net/sock.h>
 106 #include <net/tcp_states.h>
 107 #include <net/af_unix.h>
 108 #include <linux/proc_fs.h>
 109 #include <linux/seq_file.h>
 110 #include <net/scm.h>
 111 #include <linux/init.h>
 112 #include <linux/poll.h>
 113 #include <linux/rtnetlink.h>
 114 #include <linux/mount.h>
 115 #include <net/checksum.h>
 116 #include <linux/security.h>
 117
 118 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
 119 static DEFINE_SPINLOCK(unix_table_lock);
 120 static atomic_long_t unix_nr_socks;
 121
 122 #define unix_sockets_unbound    (&unix_socket_table[UNIX_HASH_SIZE])
 123
 124 #define UNIX_ABSTRACT(sk)       (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
 125
 126 #ifdef CONFIG_SECURITY_NETWORK
 127 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 128 {
 129         memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
 130 }
 131
 132 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 133 {
 134         scm->secid = *UNIXSID(skb);
 135 }
 136 #else
 137 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 138 { }
 139
 140 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 141 { }
 142 #endif /* CONFIG_SECURITY_NETWORK */
 143
 144 /*
 145  *  SMP locking strategy:
 146  *    hash table is protected with spinlock unix_table_lock
 147  *    each socket state is protected by separate spin lock.
 148  */
 149
 150 static inline unsigned unix_hash_fold(__wsum n)
 151 {
 152         unsigned hash = (__force unsigned)n;
 153         hash ^= hash>>16;
 154         hash ^= hash>>8;
 155         return hash&(UNIX_HASH_SIZE-1);
 156 }
 157
 158 #define unix_peer(sk) (unix_sk(sk)->peer)
 159
 160 static inline int unix_our_peer(struct sock *sk, struct sock *osk)
 161 {
 162         return unix_peer(osk) == sk;
 163 }
 164
 165 static inline int unix_may_send(struct sock *sk, struct sock *osk)
 166 {
 167         return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
 168 }
 169
 170 static inline int unix_recvq_full(struct sock const *sk)
 171 {
 172         return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
 173 }
 174
 175 static struct sock *unix_peer_get(struct sock *s)
 176 {
 177         struct sock *peer;
 178
 179         unix_state_lock(s);
 180         peer = unix_peer(s);
 181         if (peer)
 182                 sock_hold(peer);
 183         unix_state_unlock(s);
 184         return peer;
 185 }
 186
 187 static inline void unix_release_addr(struct unix_address *addr)
 188 {
 189         if (atomic_dec_and_test(&addr->refcnt))
 190                 kfree(addr);
 191 }
 192
 193 /*
 194  *      Check unix socket name:
 195  *              - should be not zero length.
 196  *              - if started by not zero, should be NULL terminated (FS object)
 197  *              - if started by zero, it is abstract name.
 198  */
 199
 200 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp)
 201 {
 202         if (len <= sizeof(short) || len > sizeof(*sunaddr))
 203                 return -EINVAL;
 204         if (!sunaddr || sunaddr->sun_family != AF_UNIX)
 205                 return -EINVAL;
 206         if (sunaddr->sun_path[0]) {
 207                 /*
 208                  * This may look like an off by one error but it is a bit more
 209                  * subtle. 108 is the longest valid AF_UNIX path for a binding.
 210                  * sun_path[108] doesnt as such exist.  However in kernel space
 211                  * we are guaranteed that it is a valid memory location in our
 212                  * kernel address buffer.
 213                  */
 214                 ((char *)sunaddr)[len] = 0;
 215                 len = strlen(sunaddr->sun_path)+1+sizeof(short);
 216                 return len;
 217         }
 218
 219         *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
 220         return len;
 221 }
 222
 223 static void __unix_remove_socket(struct sock *sk)
 224 {
 225         sk_del_node_init(sk);
 226 }
 227
 228 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
 229 {
 230         WARN_ON(!sk_unhashed(sk));
 231         sk_add_node(sk, list);
 232 }
 233
 234 static inline void unix_remove_socket(struct sock *sk)
 235 {
 236         spin_lock(&unix_table_lock);
 237         __unix_remove_socket(sk);
 238         spin_unlock(&unix_table_lock);
 239 }
 240
 241 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
 242 {
 243         spin_lock(&unix_table_lock);
 244         __unix_insert_socket(list, sk);
 245         spin_unlock(&unix_table_lock);
 246 }
 247
 248 static struct sock *__unix_find_socket_byname(struct net *net,
 249                                               struct sockaddr_un *sunname,
 250                                               int len, int type, unsigned hash)
 251 {
 252         struct sock *s;
 253         struct hlist_node *node;
 254
 255         sk_for_each(s, node, &unix_socket_table[hash ^ type]) {
 256                 struct unix_sock *u = unix_sk(s);
 257
 258                 if (!net_eq(sock_net(s), net))
 259                         continue;
 260
 261                 if (u->addr->len == len &&
 262                     !memcmp(u->addr->name, sunname, len))
 263                         goto found;
 264         }
 265         s = NULL;
 266 found:
 267         return s;
 268 }
 269
 270 static inline struct sock *unix_find_socket_byname(struct net *net,
 271                                                    struct sockaddr_un *sunname,
 272                                                    int len, int type,
 273                                                    unsigned hash)
 274 {
 275         struct sock *s;
 276
 277         spin_lock(&unix_table_lock);
 278         s = __unix_find_socket_byname(net, sunname, len, type, hash);
 279         if (s)
 280                 sock_hold(s);
 281         spin_unlock(&unix_table_lock);
 282         return s;
 283 }
 284
 285 static struct sock *unix_find_socket_byinode(struct inode *i)
 286 {
 287         struct sock *s;
 288         struct hlist_node *node;
 289
 290         spin_lock(&unix_table_lock);
 291         sk_for_each(s, node,
 292                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
 293                 struct dentry *dentry = unix_sk(s)->dentry;
 294
 295                 if (dentry && dentry->d_inode == i) {
 296                         sock_hold(s);
 297                         goto found;
 298                 }
 299         }
 300         s = NULL;
 301 found:
 302         spin_unlock(&unix_table_lock);
 303         return s;
 304 }
 305
 306 static inline int unix_writable(struct sock *sk)
 307 {
 308         return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
 309 }
 310
 311 static void unix_write_space(struct sock *sk)
 312 {
 313         struct socket_wq *wq;
 314
 315         rcu_read_lock();
 316         if (unix_writable(sk)) {
 317                 wq = rcu_dereference(sk->sk_wq);
 318                 if (wq_has_sleeper(wq))
 319                         wake_up_interruptible_sync_poll(&wq->wait,
 320                                 POLLOUT | POLLWRNORM | POLLWRBAND);
 321                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 322         }
 323         rcu_read_unlock();
 324 }
 325
 326 /* When dgram socket disconnects (or changes its peer), we clear its receive
 327  * queue of packets arrived from previous peer. First, it allows to do
 328  * flow control based only on wmem_alloc; second, sk connected to peer
 329  * may receive messages only from that peer. */
 330 static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
 331 {
 332         if (!skb_queue_empty(&sk->sk_receive_queue)) {
 333                 skb_queue_purge(&sk->sk_receive_queue);
 334                 wake_up_interruptible_all(&unix_sk(sk)->peer_wait);
 335
 336                 /* If one link of bidirectional dgram pipe is disconnected,
 337                  * we signal error. Messages are lost. Do not make this,
 338                  * when peer was not connected to us.
 339                  */
 340                 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
 341                         other->sk_err = ECONNRESET;
 342                         other->sk_error_report(other);
 343                 }
 344         }
 345 }
 346
 347 static void unix_sock_destructor(struct sock *sk)
 348 {
 349         struct unix_sock *u = unix_sk(sk);
 350
 351         skb_queue_purge(&sk->sk_receive_queue);
 352
 353         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
 354         WARN_ON(!sk_unhashed(sk));
 355         WARN_ON(sk->sk_socket);
 356         if (!sock_flag(sk, SOCK_DEAD)) {
 357                 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk);
 358                 return;
 359         }
 360
 361         if (u->addr)
 362                 unix_release_addr(u->addr);
 363
 364         atomic_long_dec(&unix_nr_socks);
 365         local_bh_disable();
 366         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 367         local_bh_enable();
 368 #ifdef UNIX_REFCNT_DEBUG
 369         printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
 370                 atomic_long_read(&unix_nr_socks));
 371 #endif
 372 }
 373
 374 static int unix_release_sock(struct sock *sk, int embrion)
 375 {
 376         struct unix_sock *u = unix_sk(sk);
 377         struct dentry *dentry;
 378         struct vfsmount *mnt;
 379         struct sock *skpair;
 380         struct sk_buff *skb;
 381         int state;
 382
 383         unix_remove_socket(sk);
 384
 385         /* Clear state */
 386         unix_state_lock(sk);
 387         sock_orphan(sk);
 388         sk->sk_shutdown = SHUTDOWN_MASK;
 389         dentry       = u->dentry;
 390         u->dentry    = NULL;
 391         mnt          = u->mnt;
 392         u->mnt       = NULL;
 393         state = sk->sk_state;
 394         sk->sk_state = TCP_CLOSE;
 395         unix_state_unlock(sk);
 396
 397         wake_up_interruptible_all(&u->peer_wait);
 398
 399         skpair = unix_peer(sk);
 400
 401         if (skpair != NULL) {
 402                 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
 403                         unix_state_lock(skpair);
 404                         /* No more writes */
 405                         skpair->sk_shutdown = SHUTDOWN_MASK;
 406                         if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 407                                 skpair->sk_err = ECONNRESET;
 408                         unix_state_unlock(skpair);
 409                         skpair->sk_state_change(skpair);
 410                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
 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 void init_peercred(struct sock *sk)
 452 {
 453         put_pid(sk->sk_peer_pid);
 454         if (sk->sk_peer_cred)
 455                 put_cred(sk->sk_peer_cred);
 456         sk->sk_peer_pid  = get_pid(task_tgid(current));
 457         sk->sk_peer_cred = get_current_cred();
 458 }
 459
 460 static void copy_peercred(struct sock *sk, struct sock *peersk)
 461 {
 462         put_pid(sk->sk_peer_pid);
 463         if (sk->sk_peer_cred)
 464                 put_cred(sk->sk_peer_cred);
 465         sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
 466         sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
 467 }
 468
 469 static int unix_listen(struct socket *sock, int backlog)
 470 {
 471         int err;
 472         struct sock *sk = sock->sk;
 473         struct unix_sock *u = unix_sk(sk);
 474         struct pid *old_pid = NULL;
 475         const struct cred *old_cred = NULL;
 476
 477         err = -EOPNOTSUPP;
 478         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
 479                 goto out;       /* Only stream/seqpacket sockets accept */
 480         err = -EINVAL;
 481         if (!u->addr)
 482                 goto out;       /* No listens on an unbound socket */
 483         unix_state_lock(sk);
 484         if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
 485                 goto out_unlock;
 486         if (backlog > sk->sk_max_ack_backlog)
 487                 wake_up_interruptible_all(&u->peer_wait);
 488         sk->sk_max_ack_backlog  = backlog;
 489         sk->sk_state            = TCP_LISTEN;
 490         /* set credentials so connect can copy them */
 491         init_peercred(sk);
 492         err = 0;
 493
 494 out_unlock:
 495         unix_state_unlock(sk);
 496         put_pid(old_pid);
 497         if (old_cred)
 498                 put_cred(old_cred);
 499 out:
 500         return err;
 501 }
 502
 503 static int unix_release(struct socket *);
 504 static int unix_bind(struct socket *, struct sockaddr *, int);
 505 static int unix_stream_connect(struct socket *, struct sockaddr *,
 506                                int addr_len, int flags);
 507 static int unix_socketpair(struct socket *, struct socket *);
 508 static int unix_accept(struct socket *, struct socket *, int);
 509 static int unix_getname(struct socket *, struct sockaddr *, int *, int);
 510 static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
 511 static unsigned int unix_dgram_poll(struct file *, struct socket *,
 512                                     poll_table *);
 513 static int unix_ioctl(struct socket *, unsigned int, unsigned long);
 514 static int unix_shutdown(struct socket *, int);
 515 static int unix_stream_sendmsg(struct kiocb *, struct socket *,
 516                                struct msghdr *, size_t);
 517 static int unix_stream_recvmsg(struct kiocb *, struct socket *,
 518                                struct msghdr *, size_t, int);
 519 static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
 520                               struct msghdr *, size_t);
 521 static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
 522                               struct msghdr *, size_t, int);
 523 static int unix_dgram_connect(struct socket *, struct sockaddr *,
 524                               int, int);
 525 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
 526                                   struct msghdr *, size_t);
 527
 528 static const struct proto_ops unix_stream_ops = {
 529         .family =       PF_UNIX,
 530         .owner =        THIS_MODULE,
 531         .release =      unix_release,
 532         .bind =         unix_bind,
 533         .connect =      unix_stream_connect,
 534         .socketpair =   unix_socketpair,
 535         .accept =       unix_accept,
 536         .getname =      unix_getname,
 537         .poll =         unix_poll,
 538         .ioctl =        unix_ioctl,
 539         .listen =       unix_listen,
 540         .shutdown =     unix_shutdown,
 541         .setsockopt =   sock_no_setsockopt,
 542         .getsockopt =   sock_no_getsockopt,
 543         .sendmsg =      unix_stream_sendmsg,
 544         .recvmsg =      unix_stream_recvmsg,
 545         .mmap =         sock_no_mmap,
 546         .sendpage =     sock_no_sendpage,
 547 };
 548
 549 static const struct proto_ops unix_dgram_ops = {
 550         .family =       PF_UNIX,
 551         .owner =        THIS_MODULE,
 552         .release =      unix_release,
 553         .bind =         unix_bind,
 554         .connect =      unix_dgram_connect,
 555         .socketpair =   unix_socketpair,
 556         .accept =       sock_no_accept,
 557         .getname =      unix_getname,
 558         .poll =         unix_dgram_poll,
 559         .ioctl =        unix_ioctl,
 560         .listen =       sock_no_listen,
 561         .shutdown =     unix_shutdown,
 562         .setsockopt =   sock_no_setsockopt,
 563         .getsockopt =   sock_no_getsockopt,
 564         .sendmsg =      unix_dgram_sendmsg,
 565         .recvmsg =      unix_dgram_recvmsg,
 566         .mmap =         sock_no_mmap,
 567         .sendpage =     sock_no_sendpage,
 568 };
 569
 570 static const struct proto_ops unix_seqpacket_ops = {
 571         .family =       PF_UNIX,
 572         .owner =        THIS_MODULE,
 573         .release =      unix_release,
 574         .bind =         unix_bind,
 575         .connect =      unix_stream_connect,
 576         .socketpair =   unix_socketpair,
 577         .accept =       unix_accept,
 578         .getname =      unix_getname,
 579         .poll =         unix_dgram_poll,
 580         .ioctl =        unix_ioctl,
 581         .listen =       unix_listen,
 582         .shutdown =     unix_shutdown,
 583         .setsockopt =   sock_no_setsockopt,
 584         .getsockopt =   sock_no_getsockopt,
 585         .sendmsg =      unix_seqpacket_sendmsg,
 586         .recvmsg =      unix_dgram_recvmsg,
 587         .mmap =         sock_no_mmap,
 588         .sendpage =     sock_no_sendpage,
 589 };
 590
 591 static struct proto unix_proto = {
 592         .name                   = "UNIX",
 593         .owner                  = THIS_MODULE,
 594         .obj_size               = sizeof(struct unix_sock),
 595 };
 596
 597 /*
 598  * AF_UNIX sockets do not interact with hardware, hence they
 599  * dont trigger interrupts - so it's safe for them to have
 600  * bh-unsafe locking for their sk_receive_queue.lock. Split off
 601  * this special lock-class by reinitializing the spinlock key:
 602  */
 603 static struct lock_class_key af_unix_sk_receive_queue_lock_key;
 604
 605 static struct sock *unix_create1(struct net *net, struct socket *sock)
 606 {
 607         struct sock *sk = NULL;
 608         struct unix_sock *u;
 609
 610         atomic_long_inc(&unix_nr_socks);
 611         if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
 612                 goto out;
 613
 614         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
 615         if (!sk)
 616                 goto out;
 617
 618         sock_init_data(sock, sk);
 619         lockdep_set_class(&sk->sk_receive_queue.lock,
 620                                 &af_unix_sk_receive_queue_lock_key);
 621
 622         sk->sk_write_space      = unix_write_space;
 623         sk->sk_max_ack_backlog  = net->unx.sysctl_max_dgram_qlen;
 624         sk->sk_destruct         = unix_sock_destructor;
 625         u         = unix_sk(sk);
 626         u->dentry = NULL;
 627         u->mnt    = NULL;
 628         spin_lock_init(&u->lock);
 629         atomic_long_set(&u->inflight, 0);
 630         INIT_LIST_HEAD(&u->link);
 631         mutex_init(&u->readlock); /* single task reading lock */
 632         init_waitqueue_head(&u->peer_wait);
 633         unix_insert_socket(unix_sockets_unbound, sk);
 634 out:
 635         if (sk == NULL)
 636                 atomic_long_dec(&unix_nr_socks);
 637         else {
 638                 local_bh_disable();
 639                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 640                 local_bh_enable();
 641         }
 642         return sk;
 643 }
 644
 645 static int unix_create(struct net *net, struct socket *sock, int protocol,
 646                        int kern)
 647 {
 648         if (protocol && protocol != PF_UNIX)
 649                 return -EPROTONOSUPPORT;
 650
 651         sock->state = SS_UNCONNECTED;
 652
 653         switch (sock->type) {
 654         case SOCK_STREAM:
 655                 sock->ops = &unix_stream_ops;
 656                 break;
 657                 /*
 658                  *      Believe it or not BSD has AF_UNIX, SOCK_RAW though
 659                  *      nothing uses it.
 660                  */
 661         case SOCK_RAW:
 662                 sock->type = SOCK_DGRAM;
 663         case SOCK_DGRAM:
 664                 sock->ops = &unix_dgram_ops;
 665                 break;
 666         case SOCK_SEQPACKET:
 667                 sock->ops = &unix_seqpacket_ops;
 668                 break;
 669         default:
 670                 return -ESOCKTNOSUPPORT;
 671         }
 672
 673         return unix_create1(net, sock) ? 0 : -ENOMEM;
 674 }
 675
 676 static int unix_release(struct socket *sock)
 677 {
 678         struct sock *sk = sock->sk;
 679
 680         if (!sk)
 681                 return 0;
 682
 683         sock->sk = NULL;
 684
 685         return unix_release_sock(sk, 0);
 686 }
 687
 688 static int unix_autobind(struct socket *sock)
 689 {
 690         struct sock *sk = sock->sk;
 691         struct net *net = sock_net(sk);
 692         struct unix_sock *u = unix_sk(sk);
 693         static u32 ordernum = 1;
 694         struct unix_address *addr;
 695         int err;
 696         unsigned int retries = 0;
 697
 698         mutex_lock(&u->readlock);
 699
 700         err = 0;
 701         if (u->addr)
 702                 goto out;
 703
 704         err = -ENOMEM;
 705         addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
 706         if (!addr)
 707                 goto out;
 708
 709         addr->name->sun_family = AF_UNIX;
 710         atomic_set(&addr->refcnt, 1);
 711
 712 retry:
 713         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
 714         addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
 715
 716         spin_lock(&unix_table_lock);
 717         ordernum = (ordernum+1)&0xFFFFF;
 718
 719         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
 720                                       addr->hash)) {
 721                 spin_unlock(&unix_table_lock);
 722                 /*
 723                  * __unix_find_socket_byname() may take long time if many names
 724                  * are already in use.
 725                  */
 726                 cond_resched();
 727                 /* Give up if all names seems to be in use. */
 728                 if (retries++ == 0xFFFFF) {
 729                         err = -ENOSPC;
 730                         kfree(addr);
 731                         goto out;
 732                 }
 733                 goto retry;
 734         }
 735         addr->hash ^= sk->sk_type;
 736
 737         __unix_remove_socket(sk);
 738         u->addr = addr;
 739         __unix_insert_socket(&unix_socket_table[addr->hash], sk);
 740         spin_unlock(&unix_table_lock);
 741         err = 0;
 742
 743 out:    mutex_unlock(&u->readlock);
 744         return err;
 745 }
 746
 747 static struct sock *unix_find_other(struct net *net,
 748                                     struct sockaddr_un *sunname, int len,
 749                                     int type, unsigned hash, int *error)
 750 {
 751         struct sock *u;
 752         struct path path;
 753         int err = 0;
 754
 755         if (sunname->sun_path[0]) {
 756                 struct inode *inode;
 757                 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
 758                 if (err)
 759                         goto fail;
 760                 inode = path.dentry->d_inode;
 761                 err = inode_permission(inode, MAY_WRITE);
 762                 if (err)
 763                         goto put_fail;
 764
 765                 err = -ECONNREFUSED;
 766                 if (!S_ISSOCK(inode->i_mode))
 767                         goto put_fail;
 768                 u = unix_find_socket_byinode(inode);
 769                 if (!u)
 770                         goto put_fail;
 771
 772                 if (u->sk_type == type)
 773                         touch_atime(path.mnt, path.dentry);
 774
 775                 path_put(&path);
 776
 777                 err = -EPROTOTYPE;
 778                 if (u->sk_type != type) {
 779                         sock_put(u);
 780                         goto fail;
 781                 }
 782         } else {
 783                 err = -ECONNREFUSED;
 784                 u = unix_find_socket_byname(net, sunname, len, type, hash);
 785                 if (u) {
 786                         struct dentry *dentry;
 787                         dentry = unix_sk(u)->dentry;
 788                         if (dentry)
 789                                 touch_atime(unix_sk(u)->mnt, dentry);
 790                 } else
 791                         goto fail;
 792         }
 793         return u;
 794
 795 put_fail:
 796         path_put(&path);
 797 fail:
 798         *error = err;
 799         return NULL;
 800 }
 801
 802
 803 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 804 {
 805         struct sock *sk = sock->sk;
 806         struct net *net = sock_net(sk);
 807         struct unix_sock *u = unix_sk(sk);
 808         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
 809         struct dentry *dentry = NULL;
 810         struct nameidata nd;
 811         int err;
 812         unsigned hash;
 813         struct unix_address *addr;
 814         struct hlist_head *list;
 815
 816         err = -EINVAL;
 817         if (sunaddr->sun_family != AF_UNIX)
 818                 goto out;
 819
 820         if (addr_len == sizeof(short)) {
 821                 err = unix_autobind(sock);
 822                 goto out;
 823         }
 824
 825         err = unix_mkname(sunaddr, addr_len, &hash);
 826         if (err < 0)
 827                 goto out;
 828         addr_len = err;
 829
 830         mutex_lock(&u->readlock);
 831
 832         err = -EINVAL;
 833         if (u->addr)
 834                 goto out_up;
 835
 836         err = -ENOMEM;
 837         addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
 838         if (!addr)
 839                 goto out_up;
 840
 841         memcpy(addr->name, sunaddr, addr_len);
 842         addr->len = addr_len;
 843         addr->hash = hash ^ sk->sk_type;
 844         atomic_set(&addr->refcnt, 1);
 845
 846         if (sunaddr->sun_path[0]) {
 847                 unsigned int mode;
 848                 err = 0;
 849                 /*
 850                  * Get the parent directory, calculate the hash for last
 851                  * component.
 852                  */
 853                 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd);
 854                 if (err)
 855                         goto out_mknod_parent;
 856
 857                 dentry = lookup_create(&nd, 0);
 858                 err = PTR_ERR(dentry);
 859                 if (IS_ERR(dentry))
 860                         goto out_mknod_unlock;
 861
 862                 /*
 863                  * All right, let's create it.
 864                  */
 865                 mode = S_IFSOCK |
 866                        (SOCK_INODE(sock)->i_mode & ~current_umask());
 867                 err = mnt_want_write(nd.path.mnt);
 868                 if (err)
 869                         goto out_mknod_dput;
 870                 err = security_path_mknod(&nd.path, dentry, mode, 0);
 871                 if (err)
 872                         goto out_mknod_drop_write;
 873                 err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
 874 out_mknod_drop_write:
 875                 mnt_drop_write(nd.path.mnt);
 876                 if (err)
 877                         goto out_mknod_dput;
 878                 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 879                 dput(nd.path.dentry);
 880                 nd.path.dentry = dentry;
 881
 882                 addr->hash = UNIX_HASH_SIZE;
 883         }
 884
 885         spin_lock(&unix_table_lock);
 886
 887         if (!sunaddr->sun_path[0]) {
 888                 err = -EADDRINUSE;
 889                 if (__unix_find_socket_byname(net, sunaddr, addr_len,
 890                                               sk->sk_type, hash)) {
 891                         unix_release_addr(addr);
 892                         goto out_unlock;
 893                 }
 894
 895                 list = &unix_socket_table[addr->hash];
 896         } else {
 897                 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
 898                 u->dentry = nd.path.dentry;
 899                 u->mnt    = nd.path.mnt;
 900         }
 901
 902         err = 0;
 903         __unix_remove_socket(sk);
 904         u->addr = addr;
 905         __unix_insert_socket(list, sk);
 906
 907 out_unlock:
 908         spin_unlock(&unix_table_lock);
 909 out_up:
 910         mutex_unlock(&u->readlock);
 911 out:
 912         return err;
 913
 914 out_mknod_dput:
 915         dput(dentry);
 916 out_mknod_unlock:
 917         mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 918         path_put(&nd.path);
 919 out_mknod_parent:
 920         if (err == -EEXIST)
 921                 err = -EADDRINUSE;
 922         unix_release_addr(addr);
 923         goto out_up;
 924 }
 925
 926 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
 927 {
 928         if (unlikely(sk1 == sk2) || !sk2) {
 929                 unix_state_lock(sk1);
 930                 return;
 931         }
 932         if (sk1 < sk2) {
 933                 unix_state_lock(sk1);
 934                 unix_state_lock_nested(sk2);
 935         } else {
 936                 unix_state_lock(sk2);
 937                 unix_state_lock_nested(sk1);
 938         }
 939 }
 940
 941 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
 942 {
 943         if (unlikely(sk1 == sk2) || !sk2) {
 944                 unix_state_unlock(sk1);
 945                 return;
 946         }
 947         unix_state_unlock(sk1);
 948         unix_state_unlock(sk2);
 949 }
 950
 951 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 952                               int alen, int flags)
 953 {
 954         struct sock *sk = sock->sk;
 955         struct net *net = sock_net(sk);
 956         struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
 957         struct sock *other;
 958         unsigned hash;
 959         int err;
 960
 961         if (addr->sa_family != AF_UNSPEC) {
 962                 err = unix_mkname(sunaddr, alen, &hash);
 963                 if (err < 0)
 964                         goto out;
 965                 alen = err;
 966
 967                 if (test_bit(SOCK_PASSCRED, &sock->flags) &&
 968                     !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
 969                         goto out;
 970
 971 restart:
 972                 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
 973                 if (!other)
 974                         goto out;
 975
 976                 unix_state_double_lock(sk, other);
 977
 978                 /* Apparently VFS overslept socket death. Retry. */
 979                 if (sock_flag(other, SOCK_DEAD)) {
 980                         unix_state_double_unlock(sk, other);
 981                         sock_put(other);
 982                         goto restart;
 983                 }
 984
 985                 err = -EPERM;
 986                 if (!unix_may_send(sk, other))
 987                         goto out_unlock;
 988
 989                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
 990                 if (err)
 991                         goto out_unlock;
 992
 993         } else {
 994                 /*
 995                  *      1003.1g breaking connected state with AF_UNSPEC
 996                  */
 997                 other = NULL;
 998                 unix_state_double_lock(sk, other);
 999         }
1000
1001         /*
1002          * If it was connected, reconnect.
1003          */
1004         if (unix_peer(sk)) {
1005                 struct sock *old_peer = unix_peer(sk);
1006                 unix_peer(sk) = other;
1007                 unix_state_double_unlock(sk, other);
1008
1009                 if (other != old_peer)
1010                         unix_dgram_disconnected(sk, old_peer);
1011                 sock_put(old_peer);
1012         } else {
1013                 unix_peer(sk) = other;
1014                 unix_state_double_unlock(sk, other);
1015         }
1016         return 0;
1017
1018 out_unlock:
1019         unix_state_double_unlock(sk, other);
1020         sock_put(other);
1021 out:
1022         return err;
1023 }
1024
1025 static long unix_wait_for_peer(struct sock *other, long timeo)
1026 {
1027         struct unix_sock *u = unix_sk(other);
1028         int sched;
1029         DEFINE_WAIT(wait);
1030
1031         prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);
1032
1033         sched = !sock_flag(other, SOCK_DEAD) &&
1034                 !(other->sk_shutdown & RCV_SHUTDOWN) &&
1035                 unix_recvq_full(other);
1036
1037         unix_state_unlock(other);
1038
1039         if (sched)
1040                 timeo = schedule_timeout(timeo);
1041
1042         finish_wait(&u->peer_wait, &wait);
1043         return timeo;
1044 }
1045
1046 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
1047                                int addr_len, int flags)
1048 {
1049         struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
1050         struct sock *sk = sock->sk;
1051         struct net *net = sock_net(sk);
1052         struct unix_sock *u = unix_sk(sk), *newu, *otheru;
1053         struct sock *newsk = NULL;
1054         struct sock *other = NULL;
1055         struct sk_buff *skb = NULL;
1056         unsigned hash;
1057         int st;
1058         int err;
1059         long timeo;
1060
1061         err = unix_mkname(sunaddr, addr_len, &hash);
1062         if (err < 0)
1063                 goto out;
1064         addr_len = err;
1065
1066         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
1067             (err = unix_autobind(sock)) != 0)
1068                 goto out;
1069
1070         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
1071
1072         /* First of all allocate resources.
1073            If we will make it after state is locked,
1074            we will have to recheck all again in any case.
1075          */
1076
1077         err = -ENOMEM;
1078
1079         /* create new sock for complete connection */
1080         newsk = unix_create1(sock_net(sk), NULL);
1081         if (newsk == NULL)
1082                 goto out;
1083
1084         /* Allocate skb for sending to listening sock */
1085         skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
1086         if (skb == NULL)
1087                 goto out;
1088
1089 restart:
1090         /*  Find listening sock. */
1091         other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
1092         if (!other)
1093                 goto out;
1094
1095         /* Latch state of peer */
1096         unix_state_lock(other);
1097
1098         /* Apparently VFS overslept socket death. Retry. */
1099         if (sock_flag(other, SOCK_DEAD)) {
1100                 unix_state_unlock(other);
1101                 sock_put(other);
1102                 goto restart;
1103         }
1104
1105         err = -ECONNREFUSED;
1106         if (other->sk_state != TCP_LISTEN)
1107                 goto out_unlock;
1108         if (other->sk_shutdown & RCV_SHUTDOWN)
1109                 goto out_unlock;
1110
1111         if (unix_recvq_full(other)) {
1112                 err = -EAGAIN;
1113                 if (!timeo)
1114                         goto out_unlock;
1115
1116                 timeo = unix_wait_for_peer(other, timeo);
1117
1118                 err = sock_intr_errno(timeo);
1119                 if (signal_pending(current))
1120                         goto out;
1121                 sock_put(other);
1122                 goto restart;
1123         }
1124
1125         /* Latch our state.
1126
1127            It is tricky place. We need to grab write lock and cannot
1128            drop lock on peer. It is dangerous because deadlock is
1129            possible. Connect to self case and simultaneous
1130            attempt to connect are eliminated by checking socket
1131            state. other is TCP_LISTEN, if sk is TCP_LISTEN we
1132            check this before attempt to grab lock.
1133
1134            Well, and we have to recheck the state after socket locked.
1135          */
1136         st = sk->sk_state;
1137
1138         switch (st) {
1139         case TCP_CLOSE:
1140                 /* This is ok... continue with connect */
1141                 break;
1142         case TCP_ESTABLISHED:
1143                 /* Socket is already connected */
1144                 err = -EISCONN;
1145                 goto out_unlock;
1146         default:
1147                 err = -EINVAL;
1148                 goto out_unlock;
1149         }
1150
1151         unix_state_lock_nested(sk);
1152
1153         if (sk->sk_state != st) {
1154                 unix_state_unlock(sk);
1155                 unix_state_unlock(other);
1156                 sock_put(other);
1157                 goto restart;
1158         }
1159
1160         err = security_unix_stream_connect(sk, other, newsk);
1161         if (err) {
1162                 unix_state_unlock(sk);
1163                 goto out_unlock;
1164         }
1165
1166         /* The way is open! Fastly set all the necessary fields... */
1167
1168         sock_hold(sk);
1169         unix_peer(newsk)        = sk;
1170         newsk->sk_state         = TCP_ESTABLISHED;
1171         newsk->sk_type          = sk->sk_type;
1172         init_peercred(newsk);
1173         newu = unix_sk(newsk);
1174         newsk->sk_wq            = &newu->peer_wq;
1175         otheru = unix_sk(other);
1176
1177         /* copy address information from listening to new sock*/
1178         if (otheru->addr) {
1179                 atomic_inc(&otheru->addr->refcnt);
1180                 newu->addr = otheru->addr;
1181         }
1182         if (otheru->dentry) {
1183                 newu->dentry    = dget(otheru->dentry);
1184                 newu->mnt       = mntget(otheru->mnt);
1185         }
1186
1187         /* Set credentials */
1188         copy_peercred(sk, other);
1189
1190         sock->state     = SS_CONNECTED;
1191         sk->sk_state    = TCP_ESTABLISHED;
1192         sock_hold(newsk);
1193
1194         smp_mb__after_atomic_inc();     /* sock_hold() does an atomic_inc() */
1195         unix_peer(sk)   = newsk;
1196
1197         unix_state_unlock(sk);
1198
1199         /* take ten and and send info to listening sock */
1200         spin_lock(&other->sk_receive_queue.lock);
1201         __skb_queue_tail(&other->sk_receive_queue, skb);
1202         spin_unlock(&other->sk_receive_queue.lock);
1203         unix_state_unlock(other);
1204         other->sk_data_ready(other, 0);
1205         sock_put(other);
1206         return 0;
1207
1208 out_unlock:
1209         if (other)
1210                 unix_state_unlock(other);
1211
1212 out:
1213         kfree_skb(skb);
1214         if (newsk)
1215                 unix_release_sock(newsk, 0);
1216         if (other)
1217                 sock_put(other);
1218         return err;
1219 }
1220
1221 static int unix_socketpair(struct socket *socka, struct socket *sockb)
1222 {
1223         struct sock *ska = socka->sk, *skb = sockb->sk;
1224
1225         /* Join our sockets back to back */
1226         sock_hold(ska);
1227         sock_hold(skb);
1228         unix_peer(ska) = skb;
1229         unix_peer(skb) = ska;
1230         init_peercred(ska);
1231         init_peercred(skb);
1232
1233         if (ska->sk_type != SOCK_DGRAM) {
1234                 ska->sk_state = TCP_ESTABLISHED;
1235                 skb->sk_state = TCP_ESTABLISHED;
1236                 socka->state  = SS_CONNECTED;
1237                 sockb->state  = SS_CONNECTED;
1238         }
1239         return 0;
1240 }
1241
1242 static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
1243 {
1244         struct sock *sk = sock->sk;
1245         struct sock *tsk;
1246         struct sk_buff *skb;
1247         int err;
1248
1249         err = -EOPNOTSUPP;
1250         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
1251                 goto out;
1252
1253         err = -EINVAL;
1254         if (sk->sk_state != TCP_LISTEN)
1255                 goto out;
1256
1257         /* If socket state is TCP_LISTEN it cannot change (for now...),
1258          * so that no locks are necessary.
1259          */
1260
1261         skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
1262         if (!skb) {
1263                 /* This means receive shutdown. */
1264                 if (err == 0)
1265                         err = -EINVAL;
1266                 goto out;
1267         }
1268
1269         tsk = skb->sk;
1270         skb_free_datagram(sk, skb);
1271         wake_up_interruptible(&unix_sk(sk)->peer_wait);
1272
1273         /* attach accepted sock to socket */
1274         unix_state_lock(tsk);
1275         newsock->state = SS_CONNECTED;
1276         sock_graft(tsk, newsock);
1277         unix_state_unlock(tsk);
1278         return 0;
1279
1280 out:
1281         return err;
1282 }
1283
1284
1285 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
1286 {
1287         struct sock *sk = sock->sk;
1288         struct unix_sock *u;
1289         DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
1290         int err = 0;
1291
1292         if (peer) {
1293                 sk = unix_peer_get(sk);
1294
1295                 err = -ENOTCONN;
1296                 if (!sk)
1297                         goto out;
1298                 err = 0;
1299         } else {
1300                 sock_hold(sk);
1301         }
1302
1303         u = unix_sk(sk);
1304         unix_state_lock(sk);
1305         if (!u->addr) {
1306                 sunaddr->sun_family = AF_UNIX;
1307                 sunaddr->sun_path[0] = 0;
1308                 *uaddr_len = sizeof(short);
1309         } else {
1310                 struct unix_address *addr = u->addr;
1311
1312                 *uaddr_len = addr->len;
1313                 memcpy(sunaddr, addr->name, *uaddr_len);
1314         }
1315         unix_state_unlock(sk);
1316         sock_put(sk);
1317 out:
1318         return err;
1319 }
1320
1321 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1322 {
1323         int i;
1324
1325         scm->fp = UNIXCB(skb).fp;
1326         UNIXCB(skb).fp = NULL;
1327
1328         for (i = scm->fp->count-1; i >= 0; i--)
1329                 unix_notinflight(scm->fp->fp[i]);
1330 }
1331
1332 static void unix_destruct_scm(struct sk_buff *skb)
1333 {
1334         struct scm_cookie scm;
1335         memset(&scm, 0, sizeof(scm));
1336         scm.pid  = UNIXCB(skb).pid;
1337         scm.cred = UNIXCB(skb).cred;
1338         if (UNIXCB(skb).fp)
1339                 unix_detach_fds(&scm, skb);
1340
1341         /* Alas, it calls VFS */
1342         /* So fscking what? fput() had been SMP-safe since the last Summer */
1343         scm_destroy(&scm);
1344         sock_wfree(skb);
1345 }
1346
1347 #define MAX_RECURSION_LEVEL 4
1348
1349 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
1350 {
1351         int i;
1352         unsigned char max_level = 0;
1353         int unix_sock_count = 0;
1354
1355         for (i = scm->fp->count - 1; i >= 0; i--) {
1356                 struct sock *sk = unix_get_socket(scm->fp->fp[i]);
1357
1358                 if (sk) {
1359                         unix_sock_count++;
1360                         max_level = max(max_level,
1361                                         unix_sk(sk)->recursion_level);
1362                 }
1363         }
1364         if (unlikely(max_level > MAX_RECURSION_LEVEL))
1365                 return -ETOOMANYREFS;
1366
1367         /*
1368          * Need to duplicate file references for the sake of garbage
1369          * collection.  Otherwise a socket in the fps might become a
1370          * candidate for GC while the skb is not yet queued.
1371          */
1372         UNIXCB(skb).fp = scm_fp_dup(scm->fp);
1373         if (!UNIXCB(skb).fp)
1374                 return -ENOMEM;
1375
1376         if (unix_sock_count) {
1377                 for (i = scm->fp->count - 1; i >= 0; i--)
1378                         unix_inflight(scm->fp->fp[i]);
1379         }
1380         return max_level;
1381 }
1382
1383 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1384 {
1385         int err = 0;
1386         UNIXCB(skb).pid  = get_pid(scm->pid);
1387         UNIXCB(skb).cred = get_cred(scm->cred);
1388         UNIXCB(skb).fp = NULL;
1389         if (scm->fp && send_fds)
1390                 err = unix_attach_fds(scm, skb);
1391
1392         skb->destructor = unix_destruct_scm;
1393         return err;
1394 }
1395
1396 /*
1397  *      Send AF_UNIX data.
1398  */
1399
1400 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
1401                               struct msghdr *msg, size_t len)
1402 {
1403         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1404         struct sock *sk = sock->sk;
1405         struct net *net = sock_net(sk);
1406         struct unix_sock *u = unix_sk(sk);
1407         struct sockaddr_un *sunaddr = msg->msg_name;
1408         struct sock *other = NULL;
1409         int namelen = 0; /* fake GCC */
1410         int err;
1411         unsigned hash;
1412         struct sk_buff *skb;
1413         long timeo;
1414         struct scm_cookie tmp_scm;
1415         int max_level;
1416
1417         if (NULL == siocb->scm)
1418                 siocb->scm = &tmp_scm;
1419         wait_for_unix_gc();
1420         err = scm_send(sock, msg, siocb->scm);
1421         if (err < 0)
1422                 return err;
1423
1424         err = -EOPNOTSUPP;
1425         if (msg->msg_flags&MSG_OOB)
1426                 goto out;
1427
1428         if (msg->msg_namelen) {
1429                 err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
1430                 if (err < 0)
1431                         goto out;
1432                 namelen = err;
1433         } else {
1434                 sunaddr = NULL;
1435                 err = -ENOTCONN;
1436                 other = unix_peer_get(sk);
1437                 if (!other)
1438                         goto out;
1439         }
1440
1441         if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
1442             && (err = unix_autobind(sock)) != 0)
1443                 goto out;
1444
1445         err = -EMSGSIZE;
1446         if (len > sk->sk_sndbuf - 32)
1447                 goto out;
1448
1449         skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err);
1450         if (skb == NULL)
1451                 goto out;
1452
1453         err = unix_scm_to_skb(siocb->scm, skb, true);
1454         if (err < 0)
1455                 goto out_free;
1456         max_level = err + 1;
1457         unix_get_secdata(siocb->scm, skb);
1458
1459         skb_reset_transport_header(skb);
1460         err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1461         if (err)
1462                 goto out_free;
1463
1464         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1465
1466 restart:
1467         if (!other) {
1468                 err = -ECONNRESET;
1469                 if (sunaddr == NULL)
1470                         goto out_free;
1471
1472                 other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
1473                                         hash, &err);
1474                 if (other == NULL)
1475                         goto out_free;
1476         }
1477
1478         unix_state_lock(other);
1479         err = -EPERM;
1480         if (!unix_may_send(sk, other))
1481                 goto out_unlock;
1482
1483         if (sock_flag(other, SOCK_DEAD)) {
1484                 /*
1485                  *      Check with 1003.1g - what should
1486                  *      datagram error
1487                  */
1488                 unix_state_unlock(other);
1489                 sock_put(other);
1490
1491                 err = 0;
1492                 unix_state_lock(sk);
1493                 if (unix_peer(sk) == other) {
1494                         unix_peer(sk) = NULL;
1495                         unix_state_unlock(sk);
1496
1497                         unix_dgram_disconnected(sk, other);
1498                         sock_put(other);
1499                         err = -ECONNREFUSED;
1500                 } else {
1501                         unix_state_unlock(sk);
1502                 }
1503
1504                 other = NULL;
1505                 if (err)
1506                         goto out_free;
1507                 goto restart;
1508         }
1509
1510         err = -EPIPE;
1511         if (other->sk_shutdown & RCV_SHUTDOWN)
1512                 goto out_unlock;
1513
1514         if (sk->sk_type != SOCK_SEQPACKET) {
1515                 err = security_unix_may_send(sk->sk_socket, other->sk_socket);
1516                 if (err)
1517                         goto out_unlock;
1518         }
1519
1520         if (unix_peer(other) != sk && unix_recvq_full(other)) {
1521                 if (!timeo) {
1522                         err = -EAGAIN;
1523                         goto out_unlock;
1524                 }
1525
1526                 timeo = unix_wait_for_peer(other, timeo);
1527
1528                 err = sock_intr_errno(timeo);
1529                 if (signal_pending(current))
1530                         goto out_free;
1531
1532                 goto restart;
1533         }
1534
1535         if (sock_flag(other, SOCK_RCVTSTAMP))
1536                 __net_timestamp(skb);
1537         skb_queue_tail(&other->sk_receive_queue, skb);
1538         if (max_level > unix_sk(other)->recursion_level)
1539                 unix_sk(other)->recursion_level = max_level;
1540         unix_state_unlock(other);
1541         other->sk_data_ready(other, len);
1542         sock_put(other);
1543         scm_destroy(siocb->scm);
1544         return len;
1545
1546 out_unlock:
1547         unix_state_unlock(other);
1548 out_free:
1549         kfree_skb(skb);
1550 out:
1551         if (other)
1552                 sock_put(other);
1553         scm_destroy(siocb->scm);
1554         return err;
1555 }
1556
1557
1558 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
1559                                struct msghdr *msg, size_t len)
1560 {
1561         struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1562         struct sock *sk = sock->sk;
1563         struct sock *other = NULL;
1564         struct sockaddr_un *sunaddr = msg->msg_name;
1565         int err, size;
1566         struct sk_buff *skb;
1567         int sent = 0;
1568         struct scm_cookie tmp_scm;
1569         bool fds_sent = false;
1570         int max_level;
1571
1572         if (NULL == siocb->scm)
1573                 siocb->scm = &tmp_scm;
1574         wait_for_unix_gc();
1575         err = scm_send(sock, msg, siocb->scm);
1576         if (err < 0)
1577                 return err;
1578
1579         err = -EOPNOTSUPP;
1580         if (msg->msg_flags&MSG_OOB)
1581                 goto out_err;
1582
1583         if (msg->msg_namelen) {
1584                 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
1585                 goto out_err;
1586         } else {
1587                 sunaddr = NULL;
1588                 err = -ENOTCONN;
1589                 other = unix_peer(sk);
1590                 if (!other)
1591                         goto out_err;
1592         }
1593
1594         if (sk->sk_shutdown & SEND_SHUTDOWN)
1595                 goto pipe_err;
1596
1597         while (sent < len) {
1598                 /*
1599                  *      Optimisation for the fact that under 0.01% of X
1600                  *      messages typically need breaking up.
1601                  */
1602
1603                 size = len-sent;
1604
1605                 /* Keep two messages in the pipe so it schedules better */
1606                 if (size > ((sk->sk_sndbuf >> 1) - 64))
1607                         size = (sk->sk_sndbuf >> 1) - 64;
1608
1609                 if (size > SKB_MAX_ALLOC)
1610                         size = SKB_MAX_ALLOC;
1611
1612                 /*
1613                  *      Grab a buffer
1614                  */
1615
1616                 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT,
1617                                           &err);
1618
1619                 if (skb == NULL)
1620                         goto out_err;
1621
1622                 /*
1623                  *      If you pass two values to the sock_alloc_send_skb
1624                  *      it tries to grab the large buffer with GFP_NOFS
1625                  *      (which can fail easily), and if it fails grab the
1626                  *      fallback size buffer which is under a page and will
1627                  *      succeed. [Alan]
1628                  */
1629                 size = min_t(int, size, skb_tailroom(skb));
1630
1631
1632                 /* Only send the fds in the first buffer */
1633                 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
1634                 if (err < 0) {
1635                         kfree_skb(skb);
1636                         goto out_err;
1637                 }
1638                 max_level = err + 1;
1639                 fds_sent = true;
1640
1641                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
1642                 if (err) {
1643                         kfree_skb(skb);
1644                         goto out_err;
1645                 }
1646
1647                 unix_state_lock(other);
1648
1649                 if (sock_flag(other, SOCK_DEAD) ||
1650                     (other->sk_shutdown & RCV_SHUTDOWN))
1651                         goto pipe_err_free;
1652
1653                 skb_queue_tail(&other->sk_receive_queue, skb);
1654                 if (max_level > unix_sk(other)->recursion_level)
1655                         unix_sk(other)->recursion_level = max_level;
1656                 unix_state_unlock(other);
1657                 other->sk_data_ready(other, size);
1658                 sent += size;
1659         }
1660
1661         scm_destroy(siocb->scm);
1662         siocb->scm = NULL;
1663
1664         return sent;
1665
1666 pipe_err_free:
1667         unix_state_unlock(other);
1668         kfree_skb(skb);
1669 pipe_err:
1670         if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
1671                 send_sig(SIGPIPE, current, 0);
1672         err = -EPIPE;
1673 out_err:
1674         scm_destroy(siocb->scm);
1675         siocb->scm = NULL;
1676         return sent ? : err;
1677 }
1678
1679 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
1680                                   struct msghdr *msg, size_t len)
1681 {
1682         int err;
1683         struct sock *sk = sock->sk;
1684
1685         err = sock_error(sk);
1686         if (err)
1687                 return err;
1688
1689         if (sk->sk_state != TCP_ESTABLISHED)
1690                 return -ENOTCONN;
1691
1692         if (msg->msg_namelen)
1693                 msg->msg_namelen = 0;
1694
1695         return unix_dgram_sendmsg(kiocb, sock, msg, len);
1696 }
1697
1698 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
1699 {
1700         struct unix_sock *u = unix_sk(sk);
1701
1702         msg->msg_namelen = 0;
1703         if (u->addr) {
1704                 msg->msg_namelen = u->addr->len;
1705                 memcpy(msg->msg_name, u->addr->name, u->addr->len);
1706         }
1707 }
1708
1709 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
1710                               struct msghdr *msg, size_t size,
1711                               int flags)
1712 {
1713         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1714         struct scm_cookie tmp_scm;
1715         struct sock *sk = sock->sk;
1716         struct unix_sock *u = unix_sk(sk);
1717         int noblock = flags & MSG_DONTWAIT;
1718         struct sk_buff *skb;
1719         int err;
1720
1721         err = -EOPNOTSUPP;
1722         if (flags&MSG_OOB)
1723                 goto out;
1724
1725         msg->msg_namelen = 0;
1726
1727         err = mutex_lock_interruptible(&u->readlock);
1728         if (err) {
1729                 err = sock_intr_errno(sock_rcvtimeo(sk, noblock));
1730                 goto out;
1731         }
1732
1733         skb = skb_recv_datagram(sk, flags, noblock, &err);
1734         if (!skb) {
1735                 unix_state_lock(sk);
1736                 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */
1737                 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
1738                     (sk->sk_shutdown & RCV_SHUTDOWN))
1739                         err = 0;
1740                 unix_state_unlock(sk);
1741                 goto out_unlock;
1742         }
1743
1744         wake_up_interruptible_sync_poll(&u->peer_wait,
1745                                         POLLOUT | POLLWRNORM | POLLWRBAND);
1746
1747         if (msg->msg_name)
1748                 unix_copy_addr(msg, skb->sk);
1749
1750         if (size > skb->len)
1751                 size = skb->len;
1752         else if (size < skb->len)
1753                 msg->msg_flags |= MSG_TRUNC;
1754
1755         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
1756         if (err)
1757                 goto out_free;
1758
1759         if (sock_flag(sk, SOCK_RCVTSTAMP))
1760                 __sock_recv_timestamp(msg, sk, skb);
1761
1762         if (!siocb->scm) {
1763                 siocb->scm = &tmp_scm;
1764                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1765         }
1766         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1767         unix_set_secdata(siocb->scm, skb);
1768
1769         if (!(flags & MSG_PEEK)) {
1770                 if (UNIXCB(skb).fp)
1771                         unix_detach_fds(siocb->scm, skb);
1772         } else {
1773                 /* It is questionable: on PEEK we could:
1774                    - do not return fds - good, but too simple 8)
1775                    - return fds, and do not return them on read (old strategy,
1776                      apparently wrong)
1777                    - clone fds (I chose it for now, it is the most universal
1778                      solution)
1779
1780                    POSIX 1003.1g does not actually define this clearly
1781                    at all. POSIX 1003.1g doesn't define a lot of things
1782                    clearly however!
1783
1784                 */
1785                 if (UNIXCB(skb).fp)
1786                         siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1787         }
1788         err = size;
1789
1790         scm_recv(sock, msg, siocb->scm, flags);
1791
1792 out_free:
1793         skb_free_datagram(sk, skb);
1794 out_unlock:
1795         mutex_unlock(&u->readlock);
1796 out:
1797         return err;
1798 }
1799
1800 /*
1801  *      Sleep until data has arrive. But check for races..
1802  */
1803
1804 static long unix_stream_data_wait(struct sock *sk, long timeo)
1805 {
1806         DEFINE_WAIT(wait);
1807
1808         unix_state_lock(sk);
1809
1810         for (;;) {
1811                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
1812
1813                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
1814                     sk->sk_err ||
1815                     (sk->sk_shutdown & RCV_SHUTDOWN) ||
1816                     signal_pending(current) ||
1817                     !timeo)
1818                         break;
1819
1820                 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1821                 unix_state_unlock(sk);
1822                 timeo = schedule_timeout(timeo);
1823                 unix_state_lock(sk);
1824                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1825         }
1826
1827         finish_wait(sk_sleep(sk), &wait);
1828         unix_state_unlock(sk);
1829         return timeo;
1830 }
1831
1832
1833
1834 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
1835                                struct msghdr *msg, size_t size,
1836                                int flags)
1837 {
1838         struct sock_iocb *siocb = kiocb_to_siocb(iocb);
1839         struct scm_cookie tmp_scm;
1840         struct sock *sk = sock->sk;
1841         struct unix_sock *u = unix_sk(sk);
1842         struct sockaddr_un *sunaddr = msg->msg_name;
1843         int copied = 0;
1844         int check_creds = 0;
1845         int target;
1846         int err = 0;
1847         long timeo;
1848
1849         err = -EINVAL;
1850         if (sk->sk_state != TCP_ESTABLISHED)
1851                 goto out;
1852
1853         err = -EOPNOTSUPP;
1854         if (flags&MSG_OOB)
1855                 goto out;
1856
1857         target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1858         timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
1859
1860         msg->msg_namelen = 0;
1861
1862         /* Lock the socket to prevent queue disordering
1863          * while sleeps in memcpy_tomsg
1864          */
1865
1866         if (!siocb->scm) {
1867                 siocb->scm = &tmp_scm;
1868                 memset(&tmp_scm, 0, sizeof(tmp_scm));
1869         }
1870
1871         err = mutex_lock_interruptible(&u->readlock);
1872         if (err) {
1873                 err = sock_intr_errno(timeo);
1874                 goto out;
1875         }
1876
1877         do {
1878                 int chunk;
1879                 struct sk_buff *skb;
1880
1881                 unix_state_lock(sk);
1882                 skb = skb_dequeue(&sk->sk_receive_queue);
1883                 if (skb == NULL) {
1884                         unix_sk(sk)->recursion_level = 0;
1885                         if (copied >= target)
1886                                 goto unlock;
1887
1888                         /*
1889                          *      POSIX 1003.1g mandates this order.
1890                          */
1891
1892                         err = sock_error(sk);
1893                         if (err)
1894                                 goto unlock;
1895                         if (sk->sk_shutdown & RCV_SHUTDOWN)
1896                                 goto unlock;
1897
1898                         unix_state_unlock(sk);
1899                         err = -EAGAIN;
1900                         if (!timeo)
1901                                 break;
1902                         mutex_unlock(&u->readlock);
1903
1904                         timeo = unix_stream_data_wait(sk, timeo);
1905
1906                         if (signal_pending(current)
1907                             ||  mutex_lock_interruptible(&u->readlock)) {
1908                                 err = sock_intr_errno(timeo);
1909                                 goto out;
1910                         }
1911
1912                         continue;
1913  unlock:
1914                         unix_state_unlock(sk);
1915                         break;
1916                 }
1917                 unix_state_unlock(sk);
1918
1919                 if (check_creds) {
1920                         /* Never glue messages from different writers */
1921                         if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
1922                             (UNIXCB(skb).cred != siocb->scm->cred)) {
1923                                 skb_queue_head(&sk->sk_receive_queue, skb);
1924                                 break;
1925                         }
1926                 } else {
1927                         /* Copy credentials */
1928                         scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
1929                         check_creds = 1;
1930                 }
1931
1932                 /* Copy address just once */
1933                 if (sunaddr) {
1934                         unix_copy_addr(msg, skb->sk);
1935                         sunaddr = NULL;
1936                 }
1937
1938                 chunk = min_t(unsigned int, skb->len, size);
1939                 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
1940                         skb_queue_head(&sk->sk_receive_queue, skb);
1941                         if (copied == 0)
1942                                 copied = -EFAULT;
1943                         break;
1944                 }
1945                 copied += chunk;
1946                 size -= chunk;
1947
1948                 /* Mark read part of skb as used */
1949                 if (!(flags & MSG_PEEK)) {
1950                         skb_pull(skb, chunk);
1951
1952                         if (UNIXCB(skb).fp)
1953                                 unix_detach_fds(siocb->scm, skb);
1954
1955                         /* put the skb back if we didn't use it up.. */
1956                         if (skb->len) {
1957                                 skb_queue_head(&sk->sk_receive_queue, skb);
1958                                 break;
1959                         }
1960
1961                         consume_skb(skb);
1962
1963                         if (siocb->scm->fp)
1964                                 break;
1965                 } else {
1966                         /* It is questionable, see note in unix_dgram_recvmsg.
1967                          */
1968                         if (UNIXCB(skb).fp)
1969                                 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
1970
1971                         /* put message back and return */
1972                         skb_queue_head(&sk->sk_receive_queue, skb);
1973                         break;
1974                 }
1975         } while (size);
1976
1977         mutex_unlock(&u->readlock);
1978         scm_recv(sock, msg, siocb->scm, flags);
1979 out:
1980         return copied ? : err;
1981 }
1982
1983 static int unix_shutdown(struct socket *sock, int mode)
1984 {
1985         struct sock *sk = sock->sk;
1986         struct sock *other;
1987
1988         mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
1989
1990         if (mode) {
1991                 unix_state_lock(sk);
1992                 sk->sk_shutdown |= mode;
1993                 other = unix_peer(sk);
1994                 if (other)
1995                         sock_hold(other);
1996                 unix_state_unlock(sk);
1997                 sk->sk_state_change(sk);
1998
1999                 if (other &&
2000                         (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {
2001
2002                         int peer_mode = 0;
2003
2004                         if (mode&RCV_SHUTDOWN)
2005                                 peer_mode |= SEND_SHUTDOWN;
2006                         if (mode&SEND_SHUTDOWN)
2007                                 peer_mode |= RCV_SHUTDOWN;
2008                         unix_state_lock(other);
2009                         other->sk_shutdown |= peer_mode;
2010                         unix_state_unlock(other);
2011                         other->sk_state_change(other);
2012                         if (peer_mode == SHUTDOWN_MASK)
2013                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
2014                         else if (peer_mode & RCV_SHUTDOWN)
2015                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
2016                 }
2017                 if (other)
2018                         sock_put(other);
2019         }
2020         return 0;
2021 }
2022
2023 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
2024 {
2025         struct sock *sk = sock->sk;
2026         long amount = 0;
2027         int err;
2028
2029         switch (cmd) {
2030         case SIOCOUTQ:
2031                 amount = sk_wmem_alloc_get(sk);
2032                 err = put_user(amount, (int __user *)arg);
2033                 break;
2034         case SIOCINQ:
2035                 {
2036                         struct sk_buff *skb;
2037
2038                         if (sk->sk_state == TCP_LISTEN) {
2039                                 err = -EINVAL;
2040                                 break;
2041                         }
2042
2043                         spin_lock(&sk->sk_receive_queue.lock);
2044                         if (sk->sk_type == SOCK_STREAM ||
2045                             sk->sk_type == SOCK_SEQPACKET) {
2046                                 skb_queue_walk(&sk->sk_receive_queue, skb)
2047                                         amount += skb->len;
2048                         } else {
2049                                 skb = skb_peek(&sk->sk_receive_queue);
2050                                 if (skb)
2051                                         amount = skb->len;
2052                         }
2053                         spin_unlock(&sk->sk_receive_queue.lock);
2054                         err = put_user(amount, (int __user *)arg);
2055                         break;
2056                 }
2057
2058         default:
2059                 err = -ENOIOCTLCMD;
2060                 break;
2061         }
2062         return err;
2063 }
2064
2065 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
2066 {
2067         struct sock *sk = sock->sk;
2068         unsigned int mask;
2069
2070         sock_poll_wait(file, sk_sleep(sk), wait);
2071         mask = 0;
2072
2073         /* exceptional events? */
2074         if (sk->sk_err)
2075                 mask |= POLLERR;
2076         if (sk->sk_shutdown == SHUTDOWN_MASK)
2077                 mask |= POLLHUP;
2078         if (sk->sk_shutdown & RCV_SHUTDOWN)
2079                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2080
2081         /* readable? */
2082         if (!skb_queue_empty(&sk->sk_receive_queue))
2083                 mask |= POLLIN | POLLRDNORM;
2084
2085         /* Connection-based need to check for termination and startup */
2086         if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
2087             sk->sk_state == TCP_CLOSE)
2088                 mask |= POLLHUP;
2089
2090         /*
2091          * we set writable also when the other side has shut down the
2092          * connection. This prevents stuck sockets.
2093          */
2094         if (unix_writable(sk))
2095                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2096
2097         return mask;
2098 }
2099
2100 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
2101                                     poll_table *wait)
2102 {
2103         struct sock *sk = sock->sk, *other;
2104         unsigned int mask, writable;
2105
2106         sock_poll_wait(file, sk_sleep(sk), wait);
2107         mask = 0;
2108
2109         /* exceptional events? */
2110         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2111                 mask |= POLLERR;
2112         if (sk->sk_shutdown & RCV_SHUTDOWN)
2113                 mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2114         if (sk->sk_shutdown == SHUTDOWN_MASK)
2115                 mask |= POLLHUP;
2116
2117         /* readable? */
2118         if (!skb_queue_empty(&sk->sk_receive_queue))
2119                 mask |= POLLIN | POLLRDNORM;
2120
2121         /* Connection-based need to check for termination and startup */
2122         if (sk->sk_type == SOCK_SEQPACKET) {
2123                 if (sk->sk_state == TCP_CLOSE)
2124                         mask |= POLLHUP;
2125                 /* connection hasn't started yet? */
2126                 if (sk->sk_state == TCP_SYN_SENT)
2127                         return mask;
2128         }
2129
2130         /* No write status requested, avoid expensive OUT tests. */
2131         if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
2132                 return mask;
2133
2134         writable = unix_writable(sk);
2135         other = unix_peer_get(sk);
2136         if (other) {
2137                 if (unix_peer(other) != sk) {
2138                         sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
2139                         if (unix_recvq_full(other))
2140                                 writable = 0;
2141                 }
2142                 sock_put(other);
2143         }
2144
2145         if (writable)
2146                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
2147         else
2148                 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
2149
2150         return mask;
2151 }
2152
2153 #ifdef CONFIG_PROC_FS
2154 static struct sock *first_unix_socket(int *i)
2155 {
2156         for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) {
2157                 if (!hlist_empty(&unix_socket_table[*i]))
2158                         return __sk_head(&unix_socket_table[*i]);
2159         }
2160         return NULL;
2161 }
2162
2163 static struct sock *next_unix_socket(int *i, struct sock *s)
2164 {
2165         struct sock *next = sk_next(s);
2166         /* More in this chain? */
2167         if (next)
2168                 return next;
2169         /* Look for next non-empty chain. */
2170         for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) {
2171                 if (!hlist_empty(&unix_socket_table[*i]))
2172                         return __sk_head(&unix_socket_table[*i]);
2173         }
2174         return NULL;
2175 }
2176
2177 struct unix_iter_state {
2178         struct seq_net_private p;
2179         int i;
2180 };
2181
2182 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos)
2183 {
2184         struct unix_iter_state *iter = seq->private;
2185         loff_t off = 0;
2186         struct sock *s;
2187
2188         for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {
2189                 if (sock_net(s) != seq_file_net(seq))
2190                         continue;
2191                 if (off == pos)
2192                         return s;
2193                 ++off;
2194         }
2195         return NULL;
2196 }
2197
2198 static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2199         __acquires(unix_table_lock)
2200 {
2201         spin_lock(&unix_table_lock);
2202         return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2203 }
2204
2205 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2206 {
2207         struct unix_iter_state *iter = seq->private;
2208         struct sock *sk = v;
2209         ++*pos;
2210
2211         if (v == SEQ_START_TOKEN)
2212                 sk = first_unix_socket(&iter->i);
2213         else
2214                 sk = next_unix_socket(&iter->i, sk);
2215         while (sk && (sock_net(sk) != seq_file_net(seq)))
2216                 sk = next_unix_socket(&iter->i, sk);
2217         return sk;
2218 }
2219
2220 static void unix_seq_stop(struct seq_file *seq, void *v)
2221         __releases(unix_table_lock)
2222 {
2223         spin_unlock(&unix_table_lock);
2224 }
2225
2226 static int unix_seq_show(struct seq_file *seq, void *v)
2227 {
2228
2229         if (v == SEQ_START_TOKEN)
2230                 seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
2231                          "Inode Path\n");
2232         else {
2233                 struct sock *s = v;
2234                 struct unix_sock *u = unix_sk(s);
2235                 unix_state_lock(s);
2236
2237                 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
2238                         s,
2239                         atomic_read(&s->sk_refcnt),
2240                         0,
2241                         s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
2242                         s->sk_type,
2243                         s->sk_socket ?
2244                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
2245                         (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
2246                         sock_i_ino(s));
2247
2248                 if (u->addr) {
2249                         int i, len;
2250                         seq_putc(seq, ' ');
2251
2252                         i = 0;
2253                         len = u->addr->len - sizeof(short);
2254                         if (!UNIX_ABSTRACT(s))
2255                                 len--;
2256                         else {
2257                                 seq_putc(seq, '@');
2258                                 i++;
2259                         }
2260                         for ( ; i < len; i++)
2261                                 seq_putc(seq, u->addr->name->sun_path[i]);
2262                 }
2263                 unix_state_unlock(s);
2264                 seq_putc(seq, '\n');
2265         }
2266
2267         return 0;
2268 }
2269
2270 static const struct seq_operations unix_seq_ops = {
2271         .start  = unix_seq_start,
2272         .next   = unix_seq_next,
2273         .stop   = unix_seq_stop,
2274         .show   = unix_seq_show,
2275 };
2276
2277 static int unix_seq_open(struct inode *inode, struct file *file)
2278 {
2279         return seq_open_net(inode, file, &unix_seq_ops,
2280                             sizeof(struct unix_iter_state));
2281 }
2282
2283 static const struct file_operations unix_seq_fops = {
2284         .owner          = THIS_MODULE,
2285         .open           = unix_seq_open,
2286         .read           = seq_read,
2287         .llseek         = seq_lseek,
2288         .release        = seq_release_net,
2289 };
2290
2291 #endif
2292
2293 static const struct net_proto_family unix_family_ops = {
2294         .family = PF_UNIX,
2295         .create = unix_create,
2296         .owner  = THIS_MODULE,
2297 };
2298
2299
2300 static int __net_init unix_net_init(struct net *net)
2301 {
2302         int error = -ENOMEM;
2303
2304         net->unx.sysctl_max_dgram_qlen = 10;
2305         if (unix_sysctl_register(net))
2306                 goto out;
2307
2308 #ifdef CONFIG_PROC_FS
2309         if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) {
2310                 unix_sysctl_unregister(net);
2311                 goto out;
2312         }
2313 #endif
2314         error = 0;
2315 out:
2316         return error;
2317 }
2318
2319 static void __net_exit unix_net_exit(struct net *net)
2320 {
2321         unix_sysctl_unregister(net);
2322         proc_net_remove(net, "unix");
2323 }
2324
2325 static struct pernet_operations unix_net_ops = {
2326         .init = unix_net_init,
2327         .exit = unix_net_exit,
2328 };
2329
2330 static int __init af_unix_init(void)
2331 {
2332         int rc = -1;
2333         struct sk_buff *dummy_skb;
2334
2335         BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb));
2336
2337         rc = proto_register(&unix_proto, 1);
2338         if (rc != 0) {
2339                 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n",
2340                        __func__);
2341                 goto out;
2342         }
2343
2344         sock_register(&unix_family_ops);
2345         register_pernet_subsys(&unix_net_ops);
2346 out:
2347         return rc;
2348 }
2349
2350 static void __exit af_unix_exit(void)
2351 {
2352         sock_unregister(PF_UNIX);
2353         proto_unregister(&unix_proto);
2354         unregister_pernet_subsys(&unix_net_ops);
2355 }
2356
2357 /* Earlier than device_initcall() so that other drivers invoking
2358    request_module() don't end up in a loop when modprobe tries
2359    to use a UNIX socket. But later than subsys_initcall() because
2360    we depend on stuff initialised there */
2361 fs_initcall(af_unix_init);
2362 module_exit(af_unix_exit);
2363
2364 MODULE_LICENSE("GPL");
2365 MODULE_ALIAS_NETPROTO(PF_UNIX);