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 struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1]; 119 EXPORT_SYMBOL_GPL(unix_socket_table); 120 DEFINE_SPINLOCK(unix_table_lock); 121 EXPORT_SYMBOL_GPL(unix_table_lock); 122 static atomic_long_t unix_nr_socks; 123 124 #define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE]) 125 126 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE) 127 128 #ifdef CONFIG_SECURITY_NETWORK 129 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 130 { 131 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 132 } 133 134 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 135 { 136 scm->secid = *UNIXSID(skb); 137 } 138 #else 139 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 140 { } 141 142 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 143 { } 144 #endif /* CONFIG_SECURITY_NETWORK */ 145 146 /* 147 * SMP locking strategy: 148 * hash table is protected with spinlock unix_table_lock 149 * each socket state is protected by separate spin lock. 150 */ 151 152 static inline unsigned unix_hash_fold(__wsum n) 153 { 154 unsigned hash = (__force unsigned)n; 155 hash ^= hash>>16; 156 hash ^= hash>>8; 157 return hash&(UNIX_HASH_SIZE-1); 158 } 159 160 #define unix_peer(sk) (unix_sk(sk)->peer) 161 162 static inline int unix_our_peer(struct sock *sk, struct sock *osk) 163 { 164 return unix_peer(osk) == sk; 165 } 166 167 static inline int unix_may_send(struct sock *sk, struct sock *osk) 168 { 169 return unix_peer(osk) == NULL || unix_our_peer(sk, osk); 170 } 171 172 static inline int unix_recvq_full(struct sock const *sk) 173 { 174 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; 175 } 176 177 struct sock *unix_peer_get(struct sock *s) 178 { 179 struct sock *peer; 180 181 unix_state_lock(s); 182 peer = unix_peer(s); 183 if (peer) 184 sock_hold(peer); 185 unix_state_unlock(s); 186 return peer; 187 } 188 EXPORT_SYMBOL_GPL(unix_peer_get); 189 190 static inline void unix_release_addr(struct unix_address *addr) 191 { 192 if (atomic_dec_and_test(&addr->refcnt)) 193 kfree(addr); 194 } 195 196 /* 197 * Check unix socket name: 198 * - should be not zero length. 199 * - if started by not zero, should be NULL terminated (FS object) 200 * - if started by zero, it is abstract name. 201 */ 202 203 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned *hashp) 204 { 205 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 206 return -EINVAL; 207 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 208 return -EINVAL; 209 if (sunaddr->sun_path[0]) { 210 /* 211 * This may look like an off by one error but it is a bit more 212 * subtle. 108 is the longest valid AF_UNIX path for a binding. 213 * sun_path[108] doesn't as such exist. However in kernel space 214 * we are guaranteed that it is a valid memory location in our 215 * kernel address buffer. 216 */ 217 ((char *)sunaddr)[len] = 0; 218 len = strlen(sunaddr->sun_path)+1+sizeof(short); 219 return len; 220 } 221 222 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0)); 223 return len; 224 } 225 226 static void __unix_remove_socket(struct sock *sk) 227 { 228 sk_del_node_init(sk); 229 } 230 231 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 232 { 233 WARN_ON(!sk_unhashed(sk)); 234 sk_add_node(sk, list); 235 } 236 237 static inline void unix_remove_socket(struct sock *sk) 238 { 239 spin_lock(&unix_table_lock); 240 __unix_remove_socket(sk); 241 spin_unlock(&unix_table_lock); 242 } 243 244 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 245 { 246 spin_lock(&unix_table_lock); 247 __unix_insert_socket(list, sk); 248 spin_unlock(&unix_table_lock); 249 } 250 251 static struct sock *__unix_find_socket_byname(struct net *net, 252 struct sockaddr_un *sunname, 253 int len, int type, unsigned hash) 254 { 255 struct sock *s; 256 struct hlist_node *node; 257 258 sk_for_each(s, node, &unix_socket_table[hash ^ type]) { 259 struct unix_sock *u = unix_sk(s); 260 261 if (!net_eq(sock_net(s), net)) 262 continue; 263 264 if (u->addr->len == len && 265 !memcmp(u->addr->name, sunname, len)) 266 goto found; 267 } 268 s = NULL; 269 found: 270 return s; 271 } 272 273 static inline struct sock *unix_find_socket_byname(struct net *net, 274 struct sockaddr_un *sunname, 275 int len, int type, 276 unsigned hash) 277 { 278 struct sock *s; 279 280 spin_lock(&unix_table_lock); 281 s = __unix_find_socket_byname(net, sunname, len, type, hash); 282 if (s) 283 sock_hold(s); 284 spin_unlock(&unix_table_lock); 285 return s; 286 } 287 288 static struct sock *unix_find_socket_byinode(struct inode *i) 289 { 290 struct sock *s; 291 struct hlist_node *node; 292 293 spin_lock(&unix_table_lock); 294 sk_for_each(s, node, 295 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { 296 struct dentry *dentry = unix_sk(s)->dentry; 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 struct socket_wq *wq; 317 318 rcu_read_lock(); 319 if (unix_writable(sk)) { 320 wq = rcu_dereference(sk->sk_wq); 321 if (wq_has_sleeper(wq)) 322 wake_up_interruptible_sync_poll(&wq->wait, 323 POLLOUT | POLLWRNORM | POLLWRBAND); 324 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); 325 } 326 rcu_read_unlock(); 327 } 328 329 /* When dgram socket disconnects (or changes its peer), we clear its receive 330 * queue of packets arrived from previous peer. First, it allows to do 331 * flow control based only on wmem_alloc; second, sk connected to peer 332 * may receive messages only from that peer. */ 333 static void unix_dgram_disconnected(struct sock *sk, struct sock *other) 334 { 335 if (!skb_queue_empty(&sk->sk_receive_queue)) { 336 skb_queue_purge(&sk->sk_receive_queue); 337 wake_up_interruptible_all(&unix_sk(sk)->peer_wait); 338 339 /* If one link of bidirectional dgram pipe is disconnected, 340 * we signal error. Messages are lost. Do not make this, 341 * when peer was not connected to us. 342 */ 343 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { 344 other->sk_err = ECONNRESET; 345 other->sk_error_report(other); 346 } 347 } 348 } 349 350 static void unix_sock_destructor(struct sock *sk) 351 { 352 struct unix_sock *u = unix_sk(sk); 353 354 skb_queue_purge(&sk->sk_receive_queue); 355 356 WARN_ON(atomic_read(&sk->sk_wmem_alloc)); 357 WARN_ON(!sk_unhashed(sk)); 358 WARN_ON(sk->sk_socket); 359 if (!sock_flag(sk, SOCK_DEAD)) { 360 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk); 361 return; 362 } 363 364 if (u->addr) 365 unix_release_addr(u->addr); 366 367 atomic_long_dec(&unix_nr_socks); 368 local_bh_disable(); 369 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 370 local_bh_enable(); 371 #ifdef UNIX_REFCNT_DEBUG 372 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk, 373 atomic_long_read(&unix_nr_socks)); 374 #endif 375 } 376 377 static int unix_release_sock(struct sock *sk, int embrion) 378 { 379 struct unix_sock *u = unix_sk(sk); 380 struct dentry *dentry; 381 struct vfsmount *mnt; 382 struct sock *skpair; 383 struct sk_buff *skb; 384 int state; 385 386 unix_remove_socket(sk); 387 388 /* Clear state */ 389 unix_state_lock(sk); 390 sock_orphan(sk); 391 sk->sk_shutdown = SHUTDOWN_MASK; 392 dentry = u->dentry; 393 u->dentry = NULL; 394 mnt = u->mnt; 395 u->mnt = NULL; 396 state = sk->sk_state; 397 sk->sk_state = TCP_CLOSE; 398 unix_state_unlock(sk); 399 400 wake_up_interruptible_all(&u->peer_wait); 401 402 skpair = unix_peer(sk); 403 404 if (skpair != NULL) { 405 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { 406 unix_state_lock(skpair); 407 /* No more writes */ 408 skpair->sk_shutdown = SHUTDOWN_MASK; 409 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) 410 skpair->sk_err = ECONNRESET; 411 unix_state_unlock(skpair); 412 skpair->sk_state_change(skpair); 413 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP); 414 } 415 sock_put(skpair); /* It may now die */ 416 unix_peer(sk) = NULL; 417 } 418 419 /* Try to flush out this socket. Throw out buffers at least */ 420 421 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { 422 if (state == TCP_LISTEN) 423 unix_release_sock(skb->sk, 1); 424 /* passed fds are erased in the kfree_skb hook */ 425 kfree_skb(skb); 426 } 427 428 if (dentry) { 429 dput(dentry); 430 mntput(mnt); 431 } 432 433 sock_put(sk); 434 435 /* ---- Socket is dead now and most probably destroyed ---- */ 436 437 /* 438 * Fixme: BSD difference: In BSD all sockets connected to use get 439 * ECONNRESET and we die on the spot. In Linux we behave 440 * like files and pipes do and wait for the last 441 * dereference. 442 * 443 * Can't we simply set sock->err? 444 * 445 * What the above comment does talk about? --ANK(980817) 446 */ 447 448 if (unix_tot_inflight) 449 unix_gc(); /* Garbage collect fds */ 450 451 return 0; 452 } 453 454 static void init_peercred(struct sock *sk) 455 { 456 put_pid(sk->sk_peer_pid); 457 if (sk->sk_peer_cred) 458 put_cred(sk->sk_peer_cred); 459 sk->sk_peer_pid = get_pid(task_tgid(current)); 460 sk->sk_peer_cred = get_current_cred(); 461 } 462 463 static void copy_peercred(struct sock *sk, struct sock *peersk) 464 { 465 put_pid(sk->sk_peer_pid); 466 if (sk->sk_peer_cred) 467 put_cred(sk->sk_peer_cred); 468 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); 469 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); 470 } 471 472 static int unix_listen(struct socket *sock, int backlog) 473 { 474 int err; 475 struct sock *sk = sock->sk; 476 struct unix_sock *u = unix_sk(sk); 477 struct pid *old_pid = NULL; 478 const struct cred *old_cred = NULL; 479 480 err = -EOPNOTSUPP; 481 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 482 goto out; /* Only stream/seqpacket sockets accept */ 483 err = -EINVAL; 484 if (!u->addr) 485 goto out; /* No listens on an unbound socket */ 486 unix_state_lock(sk); 487 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 488 goto out_unlock; 489 if (backlog > sk->sk_max_ack_backlog) 490 wake_up_interruptible_all(&u->peer_wait); 491 sk->sk_max_ack_backlog = backlog; 492 sk->sk_state = TCP_LISTEN; 493 /* set credentials so connect can copy them */ 494 init_peercred(sk); 495 err = 0; 496 497 out_unlock: 498 unix_state_unlock(sk); 499 put_pid(old_pid); 500 if (old_cred) 501 put_cred(old_cred); 502 out: 503 return err; 504 } 505 506 static int unix_release(struct socket *); 507 static int unix_bind(struct socket *, struct sockaddr *, int); 508 static int unix_stream_connect(struct socket *, struct sockaddr *, 509 int addr_len, int flags); 510 static int unix_socketpair(struct socket *, struct socket *); 511 static int unix_accept(struct socket *, struct socket *, int); 512 static int unix_getname(struct socket *, struct sockaddr *, int *, int); 513 static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 514 static unsigned int unix_dgram_poll(struct file *, struct socket *, 515 poll_table *); 516 static int unix_ioctl(struct socket *, unsigned int, unsigned long); 517 static int unix_shutdown(struct socket *, int); 518 static int unix_stream_sendmsg(struct kiocb *, struct socket *, 519 struct msghdr *, size_t); 520 static int unix_stream_recvmsg(struct kiocb *, struct socket *, 521 struct msghdr *, size_t, int); 522 static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 523 struct msghdr *, size_t); 524 static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 525 struct msghdr *, size_t, int); 526 static int unix_dgram_connect(struct socket *, struct sockaddr *, 527 int, int); 528 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 529 struct msghdr *, size_t); 530 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *, 531 struct msghdr *, size_t, int); 532 533 static const struct proto_ops unix_stream_ops = { 534 .family = PF_UNIX, 535 .owner = THIS_MODULE, 536 .release = unix_release, 537 .bind = unix_bind, 538 .connect = unix_stream_connect, 539 .socketpair = unix_socketpair, 540 .accept = unix_accept, 541 .getname = unix_getname, 542 .poll = unix_poll, 543 .ioctl = unix_ioctl, 544 .listen = unix_listen, 545 .shutdown = unix_shutdown, 546 .setsockopt = sock_no_setsockopt, 547 .getsockopt = sock_no_getsockopt, 548 .sendmsg = unix_stream_sendmsg, 549 .recvmsg = unix_stream_recvmsg, 550 .mmap = sock_no_mmap, 551 .sendpage = sock_no_sendpage, 552 }; 553 554 static const struct proto_ops unix_dgram_ops = { 555 .family = PF_UNIX, 556 .owner = THIS_MODULE, 557 .release = unix_release, 558 .bind = unix_bind, 559 .connect = unix_dgram_connect, 560 .socketpair = unix_socketpair, 561 .accept = sock_no_accept, 562 .getname = unix_getname, 563 .poll = unix_dgram_poll, 564 .ioctl = unix_ioctl, 565 .listen = sock_no_listen, 566 .shutdown = unix_shutdown, 567 .setsockopt = sock_no_setsockopt, 568 .getsockopt = sock_no_getsockopt, 569 .sendmsg = unix_dgram_sendmsg, 570 .recvmsg = unix_dgram_recvmsg, 571 .mmap = sock_no_mmap, 572 .sendpage = sock_no_sendpage, 573 }; 574 575 static const struct proto_ops unix_seqpacket_ops = { 576 .family = PF_UNIX, 577 .owner = THIS_MODULE, 578 .release = unix_release, 579 .bind = unix_bind, 580 .connect = unix_stream_connect, 581 .socketpair = unix_socketpair, 582 .accept = unix_accept, 583 .getname = unix_getname, 584 .poll = unix_dgram_poll, 585 .ioctl = unix_ioctl, 586 .listen = unix_listen, 587 .shutdown = unix_shutdown, 588 .setsockopt = sock_no_setsockopt, 589 .getsockopt = sock_no_getsockopt, 590 .sendmsg = unix_seqpacket_sendmsg, 591 .recvmsg = unix_seqpacket_recvmsg, 592 .mmap = sock_no_mmap, 593 .sendpage = sock_no_sendpage, 594 }; 595 596 static struct proto unix_proto = { 597 .name = "UNIX", 598 .owner = THIS_MODULE, 599 .obj_size = sizeof(struct unix_sock), 600 }; 601 602 /* 603 * AF_UNIX sockets do not interact with hardware, hence they 604 * dont trigger interrupts - so it's safe for them to have 605 * bh-unsafe locking for their sk_receive_queue.lock. Split off 606 * this special lock-class by reinitializing the spinlock key: 607 */ 608 static struct lock_class_key af_unix_sk_receive_queue_lock_key; 609 610 static struct sock *unix_create1(struct net *net, struct socket *sock) 611 { 612 struct sock *sk = NULL; 613 struct unix_sock *u; 614 615 atomic_long_inc(&unix_nr_socks); 616 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) 617 goto out; 618 619 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto); 620 if (!sk) 621 goto out; 622 623 sock_init_data(sock, sk); 624 lockdep_set_class(&sk->sk_receive_queue.lock, 625 &af_unix_sk_receive_queue_lock_key); 626 627 sk->sk_write_space = unix_write_space; 628 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; 629 sk->sk_destruct = unix_sock_destructor; 630 u = unix_sk(sk); 631 u->dentry = NULL; 632 u->mnt = NULL; 633 spin_lock_init(&u->lock); 634 atomic_long_set(&u->inflight, 0); 635 INIT_LIST_HEAD(&u->link); 636 mutex_init(&u->readlock); /* single task reading lock */ 637 init_waitqueue_head(&u->peer_wait); 638 unix_insert_socket(unix_sockets_unbound, sk); 639 out: 640 if (sk == NULL) 641 atomic_long_dec(&unix_nr_socks); 642 else { 643 local_bh_disable(); 644 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 645 local_bh_enable(); 646 } 647 return sk; 648 } 649 650 static int unix_create(struct net *net, struct socket *sock, int protocol, 651 int kern) 652 { 653 if (protocol && protocol != PF_UNIX) 654 return -EPROTONOSUPPORT; 655 656 sock->state = SS_UNCONNECTED; 657 658 switch (sock->type) { 659 case SOCK_STREAM: 660 sock->ops = &unix_stream_ops; 661 break; 662 /* 663 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 664 * nothing uses it. 665 */ 666 case SOCK_RAW: 667 sock->type = SOCK_DGRAM; 668 case SOCK_DGRAM: 669 sock->ops = &unix_dgram_ops; 670 break; 671 case SOCK_SEQPACKET: 672 sock->ops = &unix_seqpacket_ops; 673 break; 674 default: 675 return -ESOCKTNOSUPPORT; 676 } 677 678 return unix_create1(net, sock) ? 0 : -ENOMEM; 679 } 680 681 static int unix_release(struct socket *sock) 682 { 683 struct sock *sk = sock->sk; 684 685 if (!sk) 686 return 0; 687 688 sock->sk = NULL; 689 690 return unix_release_sock(sk, 0); 691 } 692 693 static int unix_autobind(struct socket *sock) 694 { 695 struct sock *sk = sock->sk; 696 struct net *net = sock_net(sk); 697 struct unix_sock *u = unix_sk(sk); 698 static u32 ordernum = 1; 699 struct unix_address *addr; 700 int err; 701 unsigned int retries = 0; 702 703 mutex_lock(&u->readlock); 704 705 err = 0; 706 if (u->addr) 707 goto out; 708 709 err = -ENOMEM; 710 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 711 if (!addr) 712 goto out; 713 714 addr->name->sun_family = AF_UNIX; 715 atomic_set(&addr->refcnt, 1); 716 717 retry: 718 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 719 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0)); 720 721 spin_lock(&unix_table_lock); 722 ordernum = (ordernum+1)&0xFFFFF; 723 724 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type, 725 addr->hash)) { 726 spin_unlock(&unix_table_lock); 727 /* 728 * __unix_find_socket_byname() may take long time if many names 729 * are already in use. 730 */ 731 cond_resched(); 732 /* Give up if all names seems to be in use. */ 733 if (retries++ == 0xFFFFF) { 734 err = -ENOSPC; 735 kfree(addr); 736 goto out; 737 } 738 goto retry; 739 } 740 addr->hash ^= sk->sk_type; 741 742 __unix_remove_socket(sk); 743 u->addr = addr; 744 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 745 spin_unlock(&unix_table_lock); 746 err = 0; 747 748 out: mutex_unlock(&u->readlock); 749 return err; 750 } 751 752 static struct sock *unix_find_other(struct net *net, 753 struct sockaddr_un *sunname, int len, 754 int type, unsigned hash, int *error) 755 { 756 struct sock *u; 757 struct path path; 758 int err = 0; 759 760 if (sunname->sun_path[0]) { 761 struct inode *inode; 762 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); 763 if (err) 764 goto fail; 765 inode = path.dentry->d_inode; 766 err = inode_permission(inode, MAY_WRITE); 767 if (err) 768 goto put_fail; 769 770 err = -ECONNREFUSED; 771 if (!S_ISSOCK(inode->i_mode)) 772 goto put_fail; 773 u = unix_find_socket_byinode(inode); 774 if (!u) 775 goto put_fail; 776 777 if (u->sk_type == type) 778 touch_atime(path.mnt, path.dentry); 779 780 path_put(&path); 781 782 err = -EPROTOTYPE; 783 if (u->sk_type != type) { 784 sock_put(u); 785 goto fail; 786 } 787 } else { 788 err = -ECONNREFUSED; 789 u = unix_find_socket_byname(net, sunname, len, type, hash); 790 if (u) { 791 struct dentry *dentry; 792 dentry = unix_sk(u)->dentry; 793 if (dentry) 794 touch_atime(unix_sk(u)->mnt, dentry); 795 } else 796 goto fail; 797 } 798 return u; 799 800 put_fail: 801 path_put(&path); 802 fail: 803 *error = err; 804 return NULL; 805 } 806 807 808 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 809 { 810 struct sock *sk = sock->sk; 811 struct net *net = sock_net(sk); 812 struct unix_sock *u = unix_sk(sk); 813 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 814 char *sun_path = sunaddr->sun_path; 815 struct dentry *dentry = NULL; 816 struct path path; 817 int err; 818 unsigned hash; 819 struct unix_address *addr; 820 struct hlist_head *list; 821 822 err = -EINVAL; 823 if (sunaddr->sun_family != AF_UNIX) 824 goto out; 825 826 if (addr_len == sizeof(short)) { 827 err = unix_autobind(sock); 828 goto out; 829 } 830 831 err = unix_mkname(sunaddr, addr_len, &hash); 832 if (err < 0) 833 goto out; 834 addr_len = err; 835 836 mutex_lock(&u->readlock); 837 838 err = -EINVAL; 839 if (u->addr) 840 goto out_up; 841 842 err = -ENOMEM; 843 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 844 if (!addr) 845 goto out_up; 846 847 memcpy(addr->name, sunaddr, addr_len); 848 addr->len = addr_len; 849 addr->hash = hash ^ sk->sk_type; 850 atomic_set(&addr->refcnt, 1); 851 852 if (sun_path[0]) { 853 umode_t mode; 854 err = 0; 855 /* 856 * Get the parent directory, calculate the hash for last 857 * component. 858 */ 859 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0); 860 err = PTR_ERR(dentry); 861 if (IS_ERR(dentry)) 862 goto out_mknod_parent; 863 864 /* 865 * All right, let's create it. 866 */ 867 mode = S_IFSOCK | 868 (SOCK_INODE(sock)->i_mode & ~current_umask()); 869 err = mnt_want_write(path.mnt); 870 if (err) 871 goto out_mknod_dput; 872 err = security_path_mknod(&path, dentry, mode, 0); 873 if (err) 874 goto out_mknod_drop_write; 875 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0); 876 out_mknod_drop_write: 877 mnt_drop_write(path.mnt); 878 if (err) 879 goto out_mknod_dput; 880 mutex_unlock(&path.dentry->d_inode->i_mutex); 881 dput(path.dentry); 882 path.dentry = dentry; 883 884 addr->hash = UNIX_HASH_SIZE; 885 } 886 887 spin_lock(&unix_table_lock); 888 889 if (!sun_path[0]) { 890 err = -EADDRINUSE; 891 if (__unix_find_socket_byname(net, sunaddr, addr_len, 892 sk->sk_type, hash)) { 893 unix_release_addr(addr); 894 goto out_unlock; 895 } 896 897 list = &unix_socket_table[addr->hash]; 898 } else { 899 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)]; 900 u->dentry = path.dentry; 901 u->mnt = path.mnt; 902 } 903 904 err = 0; 905 __unix_remove_socket(sk); 906 u->addr = addr; 907 __unix_insert_socket(list, sk); 908 909 out_unlock: 910 spin_unlock(&unix_table_lock); 911 out_up: 912 mutex_unlock(&u->readlock); 913 out: 914 return err; 915 916 out_mknod_dput: 917 dput(dentry); 918 mutex_unlock(&path.dentry->d_inode->i_mutex); 919 path_put(&path); 920 out_mknod_parent: 921 if (err == -EEXIST) 922 err = -EADDRINUSE; 923 unix_release_addr(addr); 924 goto out_up; 925 } 926 927 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) 928 { 929 if (unlikely(sk1 == sk2) || !sk2) { 930 unix_state_lock(sk1); 931 return; 932 } 933 if (sk1 < sk2) { 934 unix_state_lock(sk1); 935 unix_state_lock_nested(sk2); 936 } else { 937 unix_state_lock(sk2); 938 unix_state_lock_nested(sk1); 939 } 940 } 941 942 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) 943 { 944 if (unlikely(sk1 == sk2) || !sk2) { 945 unix_state_unlock(sk1); 946 return; 947 } 948 unix_state_unlock(sk1); 949 unix_state_unlock(sk2); 950 } 951 952 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 953 int alen, int flags) 954 { 955 struct sock *sk = sock->sk; 956 struct net *net = sock_net(sk); 957 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; 958 struct sock *other; 959 unsigned hash; 960 int err; 961 962 if (addr->sa_family != AF_UNSPEC) { 963 err = unix_mkname(sunaddr, alen, &hash); 964 if (err < 0) 965 goto out; 966 alen = err; 967 968 if (test_bit(SOCK_PASSCRED, &sock->flags) && 969 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 970 goto out; 971 972 restart: 973 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); 974 if (!other) 975 goto out; 976 977 unix_state_double_lock(sk, other); 978 979 /* Apparently VFS overslept socket death. Retry. */ 980 if (sock_flag(other, SOCK_DEAD)) { 981 unix_state_double_unlock(sk, other); 982 sock_put(other); 983 goto restart; 984 } 985 986 err = -EPERM; 987 if (!unix_may_send(sk, other)) 988 goto out_unlock; 989 990 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 991 if (err) 992 goto out_unlock; 993 994 } else { 995 /* 996 * 1003.1g breaking connected state with AF_UNSPEC 997 */ 998 other = NULL; 999 unix_state_double_lock(sk, other); 1000 } 1001 1002 /* 1003 * If it was connected, reconnect. 1004 */ 1005 if (unix_peer(sk)) { 1006 struct sock *old_peer = unix_peer(sk); 1007 unix_peer(sk) = other; 1008 unix_state_double_unlock(sk, other); 1009 1010 if (other != old_peer) 1011 unix_dgram_disconnected(sk, old_peer); 1012 sock_put(old_peer); 1013 } else { 1014 unix_peer(sk) = other; 1015 unix_state_double_unlock(sk, other); 1016 } 1017 return 0; 1018 1019 out_unlock: 1020 unix_state_double_unlock(sk, other); 1021 sock_put(other); 1022 out: 1023 return err; 1024 } 1025 1026 static long unix_wait_for_peer(struct sock *other, long timeo) 1027 { 1028 struct unix_sock *u = unix_sk(other); 1029 int sched; 1030 DEFINE_WAIT(wait); 1031 1032 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 1033 1034 sched = !sock_flag(other, SOCK_DEAD) && 1035 !(other->sk_shutdown & RCV_SHUTDOWN) && 1036 unix_recvq_full(other); 1037 1038 unix_state_unlock(other); 1039 1040 if (sched) 1041 timeo = schedule_timeout(timeo); 1042 1043 finish_wait(&u->peer_wait, &wait); 1044 return timeo; 1045 } 1046 1047 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 1048 int addr_len, int flags) 1049 { 1050 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 1051 struct sock *sk = sock->sk; 1052 struct net *net = sock_net(sk); 1053 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 1054 struct sock *newsk = NULL; 1055 struct sock *other = NULL; 1056 struct sk_buff *skb = NULL; 1057 unsigned hash; 1058 int st; 1059 int err; 1060 long timeo; 1061 1062 err = unix_mkname(sunaddr, addr_len, &hash); 1063 if (err < 0) 1064 goto out; 1065 addr_len = err; 1066 1067 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && 1068 (err = unix_autobind(sock)) != 0) 1069 goto out; 1070 1071 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 1072 1073 /* First of all allocate resources. 1074 If we will make it after state is locked, 1075 we will have to recheck all again in any case. 1076 */ 1077 1078 err = -ENOMEM; 1079 1080 /* create new sock for complete connection */ 1081 newsk = unix_create1(sock_net(sk), NULL); 1082 if (newsk == NULL) 1083 goto out; 1084 1085 /* Allocate skb for sending to listening sock */ 1086 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 1087 if (skb == NULL) 1088 goto out; 1089 1090 restart: 1091 /* Find listening sock. */ 1092 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); 1093 if (!other) 1094 goto out; 1095 1096 /* Latch state of peer */ 1097 unix_state_lock(other); 1098 1099 /* Apparently VFS overslept socket death. Retry. */ 1100 if (sock_flag(other, SOCK_DEAD)) { 1101 unix_state_unlock(other); 1102 sock_put(other); 1103 goto restart; 1104 } 1105 1106 err = -ECONNREFUSED; 1107 if (other->sk_state != TCP_LISTEN) 1108 goto out_unlock; 1109 if (other->sk_shutdown & RCV_SHUTDOWN) 1110 goto out_unlock; 1111 1112 if (unix_recvq_full(other)) { 1113 err = -EAGAIN; 1114 if (!timeo) 1115 goto out_unlock; 1116 1117 timeo = unix_wait_for_peer(other, timeo); 1118 1119 err = sock_intr_errno(timeo); 1120 if (signal_pending(current)) 1121 goto out; 1122 sock_put(other); 1123 goto restart; 1124 } 1125 1126 /* Latch our state. 1127 1128 It is tricky place. We need to grab our state lock and cannot 1129 drop lock on peer. It is dangerous because deadlock is 1130 possible. Connect to self case and simultaneous 1131 attempt to connect are eliminated by checking socket 1132 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1133 check this before attempt to grab lock. 1134 1135 Well, and we have to recheck the state after socket locked. 1136 */ 1137 st = sk->sk_state; 1138 1139 switch (st) { 1140 case TCP_CLOSE: 1141 /* This is ok... continue with connect */ 1142 break; 1143 case TCP_ESTABLISHED: 1144 /* Socket is already connected */ 1145 err = -EISCONN; 1146 goto out_unlock; 1147 default: 1148 err = -EINVAL; 1149 goto out_unlock; 1150 } 1151 1152 unix_state_lock_nested(sk); 1153 1154 if (sk->sk_state != st) { 1155 unix_state_unlock(sk); 1156 unix_state_unlock(other); 1157 sock_put(other); 1158 goto restart; 1159 } 1160 1161 err = security_unix_stream_connect(sk, other, newsk); 1162 if (err) { 1163 unix_state_unlock(sk); 1164 goto out_unlock; 1165 } 1166 1167 /* The way is open! Fastly set all the necessary fields... */ 1168 1169 sock_hold(sk); 1170 unix_peer(newsk) = sk; 1171 newsk->sk_state = TCP_ESTABLISHED; 1172 newsk->sk_type = sk->sk_type; 1173 init_peercred(newsk); 1174 newu = unix_sk(newsk); 1175 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); 1176 otheru = unix_sk(other); 1177 1178 /* copy address information from listening to new sock*/ 1179 if (otheru->addr) { 1180 atomic_inc(&otheru->addr->refcnt); 1181 newu->addr = otheru->addr; 1182 } 1183 if (otheru->dentry) { 1184 newu->dentry = dget(otheru->dentry); 1185 newu->mnt = mntget(otheru->mnt); 1186 } 1187 1188 /* Set credentials */ 1189 copy_peercred(sk, other); 1190 1191 sock->state = SS_CONNECTED; 1192 sk->sk_state = TCP_ESTABLISHED; 1193 sock_hold(newsk); 1194 1195 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1196 unix_peer(sk) = newsk; 1197 1198 unix_state_unlock(sk); 1199 1200 /* take ten and and send info to listening sock */ 1201 spin_lock(&other->sk_receive_queue.lock); 1202 __skb_queue_tail(&other->sk_receive_queue, skb); 1203 spin_unlock(&other->sk_receive_queue.lock); 1204 unix_state_unlock(other); 1205 other->sk_data_ready(other, 0); 1206 sock_put(other); 1207 return 0; 1208 1209 out_unlock: 1210 if (other) 1211 unix_state_unlock(other); 1212 1213 out: 1214 kfree_skb(skb); 1215 if (newsk) 1216 unix_release_sock(newsk, 0); 1217 if (other) 1218 sock_put(other); 1219 return err; 1220 } 1221 1222 static int unix_socketpair(struct socket *socka, struct socket *sockb) 1223 { 1224 struct sock *ska = socka->sk, *skb = sockb->sk; 1225 1226 /* Join our sockets back to back */ 1227 sock_hold(ska); 1228 sock_hold(skb); 1229 unix_peer(ska) = skb; 1230 unix_peer(skb) = ska; 1231 init_peercred(ska); 1232 init_peercred(skb); 1233 1234 if (ska->sk_type != SOCK_DGRAM) { 1235 ska->sk_state = TCP_ESTABLISHED; 1236 skb->sk_state = TCP_ESTABLISHED; 1237 socka->state = SS_CONNECTED; 1238 sockb->state = SS_CONNECTED; 1239 } 1240 return 0; 1241 } 1242 1243 static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1244 { 1245 struct sock *sk = sock->sk; 1246 struct sock *tsk; 1247 struct sk_buff *skb; 1248 int err; 1249 1250 err = -EOPNOTSUPP; 1251 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 1252 goto out; 1253 1254 err = -EINVAL; 1255 if (sk->sk_state != TCP_LISTEN) 1256 goto out; 1257 1258 /* If socket state is TCP_LISTEN it cannot change (for now...), 1259 * so that no locks are necessary. 1260 */ 1261 1262 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1263 if (!skb) { 1264 /* This means receive shutdown. */ 1265 if (err == 0) 1266 err = -EINVAL; 1267 goto out; 1268 } 1269 1270 tsk = skb->sk; 1271 skb_free_datagram(sk, skb); 1272 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1273 1274 /* attach accepted sock to socket */ 1275 unix_state_lock(tsk); 1276 newsock->state = SS_CONNECTED; 1277 sock_graft(tsk, newsock); 1278 unix_state_unlock(tsk); 1279 return 0; 1280 1281 out: 1282 return err; 1283 } 1284 1285 1286 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1287 { 1288 struct sock *sk = sock->sk; 1289 struct unix_sock *u; 1290 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); 1291 int err = 0; 1292 1293 if (peer) { 1294 sk = unix_peer_get(sk); 1295 1296 err = -ENOTCONN; 1297 if (!sk) 1298 goto out; 1299 err = 0; 1300 } else { 1301 sock_hold(sk); 1302 } 1303 1304 u = unix_sk(sk); 1305 unix_state_lock(sk); 1306 if (!u->addr) { 1307 sunaddr->sun_family = AF_UNIX; 1308 sunaddr->sun_path[0] = 0; 1309 *uaddr_len = sizeof(short); 1310 } else { 1311 struct unix_address *addr = u->addr; 1312 1313 *uaddr_len = addr->len; 1314 memcpy(sunaddr, addr->name, *uaddr_len); 1315 } 1316 unix_state_unlock(sk); 1317 sock_put(sk); 1318 out: 1319 return err; 1320 } 1321 1322 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1323 { 1324 int i; 1325 1326 scm->fp = UNIXCB(skb).fp; 1327 UNIXCB(skb).fp = NULL; 1328 1329 for (i = scm->fp->count-1; i >= 0; i--) 1330 unix_notinflight(scm->fp->fp[i]); 1331 } 1332 1333 static void unix_destruct_scm(struct sk_buff *skb) 1334 { 1335 struct scm_cookie scm; 1336 memset(&scm, 0, sizeof(scm)); 1337 scm.pid = UNIXCB(skb).pid; 1338 scm.cred = UNIXCB(skb).cred; 1339 if (UNIXCB(skb).fp) 1340 unix_detach_fds(&scm, skb); 1341 1342 /* Alas, it calls VFS */ 1343 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1344 scm_destroy(&scm); 1345 sock_wfree(skb); 1346 } 1347 1348 #define MAX_RECURSION_LEVEL 4 1349 1350 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1351 { 1352 int i; 1353 unsigned char max_level = 0; 1354 int unix_sock_count = 0; 1355 1356 for (i = scm->fp->count - 1; i >= 0; i--) { 1357 struct sock *sk = unix_get_socket(scm->fp->fp[i]); 1358 1359 if (sk) { 1360 unix_sock_count++; 1361 max_level = max(max_level, 1362 unix_sk(sk)->recursion_level); 1363 } 1364 } 1365 if (unlikely(max_level > MAX_RECURSION_LEVEL)) 1366 return -ETOOMANYREFS; 1367 1368 /* 1369 * Need to duplicate file references for the sake of garbage 1370 * collection. Otherwise a socket in the fps might become a 1371 * candidate for GC while the skb is not yet queued. 1372 */ 1373 UNIXCB(skb).fp = scm_fp_dup(scm->fp); 1374 if (!UNIXCB(skb).fp) 1375 return -ENOMEM; 1376 1377 if (unix_sock_count) { 1378 for (i = scm->fp->count - 1; i >= 0; i--) 1379 unix_inflight(scm->fp->fp[i]); 1380 } 1381 return max_level; 1382 } 1383 1384 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) 1385 { 1386 int err = 0; 1387 1388 UNIXCB(skb).pid = get_pid(scm->pid); 1389 if (scm->cred) 1390 UNIXCB(skb).cred = get_cred(scm->cred); 1391 UNIXCB(skb).fp = NULL; 1392 if (scm->fp && send_fds) 1393 err = unix_attach_fds(scm, skb); 1394 1395 skb->destructor = unix_destruct_scm; 1396 return err; 1397 } 1398 1399 /* 1400 * Some apps rely on write() giving SCM_CREDENTIALS 1401 * We include credentials if source or destination socket 1402 * asserted SOCK_PASSCRED. 1403 */ 1404 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, 1405 const struct sock *other) 1406 { 1407 if (UNIXCB(skb).cred) 1408 return; 1409 if (test_bit(SOCK_PASSCRED, &sock->flags) || 1410 !other->sk_socket || 1411 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { 1412 UNIXCB(skb).pid = get_pid(task_tgid(current)); 1413 UNIXCB(skb).cred = get_current_cred(); 1414 } 1415 } 1416 1417 /* 1418 * Send AF_UNIX data. 1419 */ 1420 1421 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1422 struct msghdr *msg, size_t len) 1423 { 1424 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1425 struct sock *sk = sock->sk; 1426 struct net *net = sock_net(sk); 1427 struct unix_sock *u = unix_sk(sk); 1428 struct sockaddr_un *sunaddr = msg->msg_name; 1429 struct sock *other = NULL; 1430 int namelen = 0; /* fake GCC */ 1431 int err; 1432 unsigned hash; 1433 struct sk_buff *skb; 1434 long timeo; 1435 struct scm_cookie tmp_scm; 1436 int max_level; 1437 1438 if (NULL == siocb->scm) 1439 siocb->scm = &tmp_scm; 1440 wait_for_unix_gc(); 1441 err = scm_send(sock, msg, siocb->scm); 1442 if (err < 0) 1443 return err; 1444 1445 err = -EOPNOTSUPP; 1446 if (msg->msg_flags&MSG_OOB) 1447 goto out; 1448 1449 if (msg->msg_namelen) { 1450 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1451 if (err < 0) 1452 goto out; 1453 namelen = err; 1454 } else { 1455 sunaddr = NULL; 1456 err = -ENOTCONN; 1457 other = unix_peer_get(sk); 1458 if (!other) 1459 goto out; 1460 } 1461 1462 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr 1463 && (err = unix_autobind(sock)) != 0) 1464 goto out; 1465 1466 err = -EMSGSIZE; 1467 if (len > sk->sk_sndbuf - 32) 1468 goto out; 1469 1470 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err); 1471 if (skb == NULL) 1472 goto out; 1473 1474 err = unix_scm_to_skb(siocb->scm, skb, true); 1475 if (err < 0) 1476 goto out_free; 1477 max_level = err + 1; 1478 unix_get_secdata(siocb->scm, skb); 1479 1480 skb_reset_transport_header(skb); 1481 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len); 1482 if (err) 1483 goto out_free; 1484 1485 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1486 1487 restart: 1488 if (!other) { 1489 err = -ECONNRESET; 1490 if (sunaddr == NULL) 1491 goto out_free; 1492 1493 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1494 hash, &err); 1495 if (other == NULL) 1496 goto out_free; 1497 } 1498 1499 if (sk_filter(other, skb) < 0) { 1500 /* Toss the packet but do not return any error to the sender */ 1501 err = len; 1502 goto out_free; 1503 } 1504 1505 unix_state_lock(other); 1506 err = -EPERM; 1507 if (!unix_may_send(sk, other)) 1508 goto out_unlock; 1509 1510 if (sock_flag(other, SOCK_DEAD)) { 1511 /* 1512 * Check with 1003.1g - what should 1513 * datagram error 1514 */ 1515 unix_state_unlock(other); 1516 sock_put(other); 1517 1518 err = 0; 1519 unix_state_lock(sk); 1520 if (unix_peer(sk) == other) { 1521 unix_peer(sk) = NULL; 1522 unix_state_unlock(sk); 1523 1524 unix_dgram_disconnected(sk, other); 1525 sock_put(other); 1526 err = -ECONNREFUSED; 1527 } else { 1528 unix_state_unlock(sk); 1529 } 1530 1531 other = NULL; 1532 if (err) 1533 goto out_free; 1534 goto restart; 1535 } 1536 1537 err = -EPIPE; 1538 if (other->sk_shutdown & RCV_SHUTDOWN) 1539 goto out_unlock; 1540 1541 if (sk->sk_type != SOCK_SEQPACKET) { 1542 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1543 if (err) 1544 goto out_unlock; 1545 } 1546 1547 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1548 if (!timeo) { 1549 err = -EAGAIN; 1550 goto out_unlock; 1551 } 1552 1553 timeo = unix_wait_for_peer(other, timeo); 1554 1555 err = sock_intr_errno(timeo); 1556 if (signal_pending(current)) 1557 goto out_free; 1558 1559 goto restart; 1560 } 1561 1562 if (sock_flag(other, SOCK_RCVTSTAMP)) 1563 __net_timestamp(skb); 1564 maybe_add_creds(skb, sock, other); 1565 skb_queue_tail(&other->sk_receive_queue, skb); 1566 if (max_level > unix_sk(other)->recursion_level) 1567 unix_sk(other)->recursion_level = max_level; 1568 unix_state_unlock(other); 1569 other->sk_data_ready(other, len); 1570 sock_put(other); 1571 scm_destroy(siocb->scm); 1572 return len; 1573 1574 out_unlock: 1575 unix_state_unlock(other); 1576 out_free: 1577 kfree_skb(skb); 1578 out: 1579 if (other) 1580 sock_put(other); 1581 scm_destroy(siocb->scm); 1582 return err; 1583 } 1584 1585 1586 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1587 struct msghdr *msg, size_t len) 1588 { 1589 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1590 struct sock *sk = sock->sk; 1591 struct sock *other = NULL; 1592 int err, size; 1593 struct sk_buff *skb; 1594 int sent = 0; 1595 struct scm_cookie tmp_scm; 1596 bool fds_sent = false; 1597 int max_level; 1598 1599 if (NULL == siocb->scm) 1600 siocb->scm = &tmp_scm; 1601 wait_for_unix_gc(); 1602 err = scm_send(sock, msg, siocb->scm); 1603 if (err < 0) 1604 return err; 1605 1606 err = -EOPNOTSUPP; 1607 if (msg->msg_flags&MSG_OOB) 1608 goto out_err; 1609 1610 if (msg->msg_namelen) { 1611 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1612 goto out_err; 1613 } else { 1614 err = -ENOTCONN; 1615 other = unix_peer(sk); 1616 if (!other) 1617 goto out_err; 1618 } 1619 1620 if (sk->sk_shutdown & SEND_SHUTDOWN) 1621 goto pipe_err; 1622 1623 while (sent < len) { 1624 /* 1625 * Optimisation for the fact that under 0.01% of X 1626 * messages typically need breaking up. 1627 */ 1628 1629 size = len-sent; 1630 1631 /* Keep two messages in the pipe so it schedules better */ 1632 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1633 size = (sk->sk_sndbuf >> 1) - 64; 1634 1635 if (size > SKB_MAX_ALLOC) 1636 size = SKB_MAX_ALLOC; 1637 1638 /* 1639 * Grab a buffer 1640 */ 1641 1642 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT, 1643 &err); 1644 1645 if (skb == NULL) 1646 goto out_err; 1647 1648 /* 1649 * If you pass two values to the sock_alloc_send_skb 1650 * it tries to grab the large buffer with GFP_NOFS 1651 * (which can fail easily), and if it fails grab the 1652 * fallback size buffer which is under a page and will 1653 * succeed. [Alan] 1654 */ 1655 size = min_t(int, size, skb_tailroom(skb)); 1656 1657 1658 /* Only send the fds in the first buffer */ 1659 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1660 if (err < 0) { 1661 kfree_skb(skb); 1662 goto out_err; 1663 } 1664 max_level = err + 1; 1665 fds_sent = true; 1666 1667 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size); 1668 if (err) { 1669 kfree_skb(skb); 1670 goto out_err; 1671 } 1672 1673 unix_state_lock(other); 1674 1675 if (sock_flag(other, SOCK_DEAD) || 1676 (other->sk_shutdown & RCV_SHUTDOWN)) 1677 goto pipe_err_free; 1678 1679 maybe_add_creds(skb, sock, other); 1680 skb_queue_tail(&other->sk_receive_queue, skb); 1681 if (max_level > unix_sk(other)->recursion_level) 1682 unix_sk(other)->recursion_level = max_level; 1683 unix_state_unlock(other); 1684 other->sk_data_ready(other, size); 1685 sent += size; 1686 } 1687 1688 scm_destroy(siocb->scm); 1689 siocb->scm = NULL; 1690 1691 return sent; 1692 1693 pipe_err_free: 1694 unix_state_unlock(other); 1695 kfree_skb(skb); 1696 pipe_err: 1697 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1698 send_sig(SIGPIPE, current, 0); 1699 err = -EPIPE; 1700 out_err: 1701 scm_destroy(siocb->scm); 1702 siocb->scm = NULL; 1703 return sent ? : err; 1704 } 1705 1706 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1707 struct msghdr *msg, size_t len) 1708 { 1709 int err; 1710 struct sock *sk = sock->sk; 1711 1712 err = sock_error(sk); 1713 if (err) 1714 return err; 1715 1716 if (sk->sk_state != TCP_ESTABLISHED) 1717 return -ENOTCONN; 1718 1719 if (msg->msg_namelen) 1720 msg->msg_namelen = 0; 1721 1722 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1723 } 1724 1725 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1726 struct msghdr *msg, size_t size, 1727 int flags) 1728 { 1729 struct sock *sk = sock->sk; 1730 1731 if (sk->sk_state != TCP_ESTABLISHED) 1732 return -ENOTCONN; 1733 1734 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1735 } 1736 1737 static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1738 { 1739 struct unix_sock *u = unix_sk(sk); 1740 1741 msg->msg_namelen = 0; 1742 if (u->addr) { 1743 msg->msg_namelen = u->addr->len; 1744 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1745 } 1746 } 1747 1748 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1749 struct msghdr *msg, size_t size, 1750 int flags) 1751 { 1752 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1753 struct scm_cookie tmp_scm; 1754 struct sock *sk = sock->sk; 1755 struct unix_sock *u = unix_sk(sk); 1756 int noblock = flags & MSG_DONTWAIT; 1757 struct sk_buff *skb; 1758 int err; 1759 1760 err = -EOPNOTSUPP; 1761 if (flags&MSG_OOB) 1762 goto out; 1763 1764 msg->msg_namelen = 0; 1765 1766 err = mutex_lock_interruptible(&u->readlock); 1767 if (err) { 1768 err = sock_intr_errno(sock_rcvtimeo(sk, noblock)); 1769 goto out; 1770 } 1771 1772 skb = skb_recv_datagram(sk, flags, noblock, &err); 1773 if (!skb) { 1774 unix_state_lock(sk); 1775 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1776 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1777 (sk->sk_shutdown & RCV_SHUTDOWN)) 1778 err = 0; 1779 unix_state_unlock(sk); 1780 goto out_unlock; 1781 } 1782 1783 wake_up_interruptible_sync_poll(&u->peer_wait, 1784 POLLOUT | POLLWRNORM | POLLWRBAND); 1785 1786 if (msg->msg_name) 1787 unix_copy_addr(msg, skb->sk); 1788 1789 if (size > skb->len) 1790 size = skb->len; 1791 else if (size < skb->len) 1792 msg->msg_flags |= MSG_TRUNC; 1793 1794 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size); 1795 if (err) 1796 goto out_free; 1797 1798 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1799 __sock_recv_timestamp(msg, sk, skb); 1800 1801 if (!siocb->scm) { 1802 siocb->scm = &tmp_scm; 1803 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1804 } 1805 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 1806 unix_set_secdata(siocb->scm, skb); 1807 1808 if (!(flags & MSG_PEEK)) { 1809 if (UNIXCB(skb).fp) 1810 unix_detach_fds(siocb->scm, skb); 1811 } else { 1812 /* It is questionable: on PEEK we could: 1813 - do not return fds - good, but too simple 8) 1814 - return fds, and do not return them on read (old strategy, 1815 apparently wrong) 1816 - clone fds (I chose it for now, it is the most universal 1817 solution) 1818 1819 POSIX 1003.1g does not actually define this clearly 1820 at all. POSIX 1003.1g doesn't define a lot of things 1821 clearly however! 1822 1823 */ 1824 if (UNIXCB(skb).fp) 1825 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1826 } 1827 err = size; 1828 1829 scm_recv(sock, msg, siocb->scm, flags); 1830 1831 out_free: 1832 skb_free_datagram(sk, skb); 1833 out_unlock: 1834 mutex_unlock(&u->readlock); 1835 out: 1836 return err; 1837 } 1838 1839 /* 1840 * Sleep until data has arrive. But check for races.. 1841 */ 1842 1843 static long unix_stream_data_wait(struct sock *sk, long timeo) 1844 { 1845 DEFINE_WAIT(wait); 1846 1847 unix_state_lock(sk); 1848 1849 for (;;) { 1850 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1851 1852 if (!skb_queue_empty(&sk->sk_receive_queue) || 1853 sk->sk_err || 1854 (sk->sk_shutdown & RCV_SHUTDOWN) || 1855 signal_pending(current) || 1856 !timeo) 1857 break; 1858 1859 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1860 unix_state_unlock(sk); 1861 timeo = schedule_timeout(timeo); 1862 unix_state_lock(sk); 1863 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1864 } 1865 1866 finish_wait(sk_sleep(sk), &wait); 1867 unix_state_unlock(sk); 1868 return timeo; 1869 } 1870 1871 1872 1873 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1874 struct msghdr *msg, size_t size, 1875 int flags) 1876 { 1877 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1878 struct scm_cookie tmp_scm; 1879 struct sock *sk = sock->sk; 1880 struct unix_sock *u = unix_sk(sk); 1881 struct sockaddr_un *sunaddr = msg->msg_name; 1882 int copied = 0; 1883 int check_creds = 0; 1884 int target; 1885 int err = 0; 1886 long timeo; 1887 1888 err = -EINVAL; 1889 if (sk->sk_state != TCP_ESTABLISHED) 1890 goto out; 1891 1892 err = -EOPNOTSUPP; 1893 if (flags&MSG_OOB) 1894 goto out; 1895 1896 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1897 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1898 1899 msg->msg_namelen = 0; 1900 1901 /* Lock the socket to prevent queue disordering 1902 * while sleeps in memcpy_tomsg 1903 */ 1904 1905 if (!siocb->scm) { 1906 siocb->scm = &tmp_scm; 1907 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1908 } 1909 1910 err = mutex_lock_interruptible(&u->readlock); 1911 if (err) { 1912 err = sock_intr_errno(timeo); 1913 goto out; 1914 } 1915 1916 do { 1917 int chunk; 1918 struct sk_buff *skb; 1919 1920 unix_state_lock(sk); 1921 skb = skb_dequeue(&sk->sk_receive_queue); 1922 if (skb == NULL) { 1923 unix_sk(sk)->recursion_level = 0; 1924 if (copied >= target) 1925 goto unlock; 1926 1927 /* 1928 * POSIX 1003.1g mandates this order. 1929 */ 1930 1931 err = sock_error(sk); 1932 if (err) 1933 goto unlock; 1934 if (sk->sk_shutdown & RCV_SHUTDOWN) 1935 goto unlock; 1936 1937 unix_state_unlock(sk); 1938 err = -EAGAIN; 1939 if (!timeo) 1940 break; 1941 mutex_unlock(&u->readlock); 1942 1943 timeo = unix_stream_data_wait(sk, timeo); 1944 1945 if (signal_pending(current) 1946 || mutex_lock_interruptible(&u->readlock)) { 1947 err = sock_intr_errno(timeo); 1948 goto out; 1949 } 1950 1951 continue; 1952 unlock: 1953 unix_state_unlock(sk); 1954 break; 1955 } 1956 unix_state_unlock(sk); 1957 1958 if (check_creds) { 1959 /* Never glue messages from different writers */ 1960 if ((UNIXCB(skb).pid != siocb->scm->pid) || 1961 (UNIXCB(skb).cred != siocb->scm->cred)) { 1962 skb_queue_head(&sk->sk_receive_queue, skb); 1963 sk->sk_data_ready(sk, skb->len); 1964 break; 1965 } 1966 } else { 1967 /* Copy credentials */ 1968 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 1969 check_creds = 1; 1970 } 1971 1972 /* Copy address just once */ 1973 if (sunaddr) { 1974 unix_copy_addr(msg, skb->sk); 1975 sunaddr = NULL; 1976 } 1977 1978 chunk = min_t(unsigned int, skb->len, size); 1979 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) { 1980 skb_queue_head(&sk->sk_receive_queue, skb); 1981 sk->sk_data_ready(sk, skb->len); 1982 if (copied == 0) 1983 copied = -EFAULT; 1984 break; 1985 } 1986 copied += chunk; 1987 size -= chunk; 1988 1989 /* Mark read part of skb as used */ 1990 if (!(flags & MSG_PEEK)) { 1991 skb_pull(skb, chunk); 1992 1993 if (UNIXCB(skb).fp) 1994 unix_detach_fds(siocb->scm, skb); 1995 1996 /* put the skb back if we didn't use it up.. */ 1997 if (skb->len) { 1998 skb_queue_head(&sk->sk_receive_queue, skb); 1999 sk->sk_data_ready(sk, skb->len); 2000 break; 2001 } 2002 2003 consume_skb(skb); 2004 2005 if (siocb->scm->fp) 2006 break; 2007 } else { 2008 /* It is questionable, see note in unix_dgram_recvmsg. 2009 */ 2010 if (UNIXCB(skb).fp) 2011 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2012 2013 /* put message back and return */ 2014 skb_queue_head(&sk->sk_receive_queue, skb); 2015 sk->sk_data_ready(sk, skb->len); 2016 break; 2017 } 2018 } while (size); 2019 2020 mutex_unlock(&u->readlock); 2021 scm_recv(sock, msg, siocb->scm, flags); 2022 out: 2023 return copied ? : err; 2024 } 2025 2026 static int unix_shutdown(struct socket *sock, int mode) 2027 { 2028 struct sock *sk = sock->sk; 2029 struct sock *other; 2030 2031 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN); 2032 2033 if (!mode) 2034 return 0; 2035 2036 unix_state_lock(sk); 2037 sk->sk_shutdown |= mode; 2038 other = unix_peer(sk); 2039 if (other) 2040 sock_hold(other); 2041 unix_state_unlock(sk); 2042 sk->sk_state_change(sk); 2043 2044 if (other && 2045 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2046 2047 int peer_mode = 0; 2048 2049 if (mode&RCV_SHUTDOWN) 2050 peer_mode |= SEND_SHUTDOWN; 2051 if (mode&SEND_SHUTDOWN) 2052 peer_mode |= RCV_SHUTDOWN; 2053 unix_state_lock(other); 2054 other->sk_shutdown |= peer_mode; 2055 unix_state_unlock(other); 2056 other->sk_state_change(other); 2057 if (peer_mode == SHUTDOWN_MASK) 2058 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2059 else if (peer_mode & RCV_SHUTDOWN) 2060 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2061 } 2062 if (other) 2063 sock_put(other); 2064 2065 return 0; 2066 } 2067 2068 long unix_inq_len(struct sock *sk) 2069 { 2070 struct sk_buff *skb; 2071 long amount = 0; 2072 2073 if (sk->sk_state == TCP_LISTEN) 2074 return -EINVAL; 2075 2076 spin_lock(&sk->sk_receive_queue.lock); 2077 if (sk->sk_type == SOCK_STREAM || 2078 sk->sk_type == SOCK_SEQPACKET) { 2079 skb_queue_walk(&sk->sk_receive_queue, skb) 2080 amount += skb->len; 2081 } else { 2082 skb = skb_peek(&sk->sk_receive_queue); 2083 if (skb) 2084 amount = skb->len; 2085 } 2086 spin_unlock(&sk->sk_receive_queue.lock); 2087 2088 return amount; 2089 } 2090 EXPORT_SYMBOL_GPL(unix_inq_len); 2091 2092 long unix_outq_len(struct sock *sk) 2093 { 2094 return sk_wmem_alloc_get(sk); 2095 } 2096 EXPORT_SYMBOL_GPL(unix_outq_len); 2097 2098 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2099 { 2100 struct sock *sk = sock->sk; 2101 long amount = 0; 2102 int err; 2103 2104 switch (cmd) { 2105 case SIOCOUTQ: 2106 amount = unix_outq_len(sk); 2107 err = put_user(amount, (int __user *)arg); 2108 break; 2109 case SIOCINQ: 2110 amount = unix_inq_len(sk); 2111 if (amount < 0) 2112 err = amount; 2113 else 2114 err = put_user(amount, (int __user *)arg); 2115 break; 2116 default: 2117 err = -ENOIOCTLCMD; 2118 break; 2119 } 2120 return err; 2121 } 2122 2123 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2124 { 2125 struct sock *sk = sock->sk; 2126 unsigned int mask; 2127 2128 sock_poll_wait(file, sk_sleep(sk), wait); 2129 mask = 0; 2130 2131 /* exceptional events? */ 2132 if (sk->sk_err) 2133 mask |= POLLERR; 2134 if (sk->sk_shutdown == SHUTDOWN_MASK) 2135 mask |= POLLHUP; 2136 if (sk->sk_shutdown & RCV_SHUTDOWN) 2137 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2138 2139 /* readable? */ 2140 if (!skb_queue_empty(&sk->sk_receive_queue)) 2141 mask |= POLLIN | POLLRDNORM; 2142 2143 /* Connection-based need to check for termination and startup */ 2144 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2145 sk->sk_state == TCP_CLOSE) 2146 mask |= POLLHUP; 2147 2148 /* 2149 * we set writable also when the other side has shut down the 2150 * connection. This prevents stuck sockets. 2151 */ 2152 if (unix_writable(sk)) 2153 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2154 2155 return mask; 2156 } 2157 2158 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2159 poll_table *wait) 2160 { 2161 struct sock *sk = sock->sk, *other; 2162 unsigned int mask, writable; 2163 2164 sock_poll_wait(file, sk_sleep(sk), wait); 2165 mask = 0; 2166 2167 /* exceptional events? */ 2168 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2169 mask |= POLLERR; 2170 if (sk->sk_shutdown & RCV_SHUTDOWN) 2171 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2172 if (sk->sk_shutdown == SHUTDOWN_MASK) 2173 mask |= POLLHUP; 2174 2175 /* readable? */ 2176 if (!skb_queue_empty(&sk->sk_receive_queue)) 2177 mask |= POLLIN | POLLRDNORM; 2178 2179 /* Connection-based need to check for termination and startup */ 2180 if (sk->sk_type == SOCK_SEQPACKET) { 2181 if (sk->sk_state == TCP_CLOSE) 2182 mask |= POLLHUP; 2183 /* connection hasn't started yet? */ 2184 if (sk->sk_state == TCP_SYN_SENT) 2185 return mask; 2186 } 2187 2188 /* No write status requested, avoid expensive OUT tests. */ 2189 if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT))) 2190 return mask; 2191 2192 writable = unix_writable(sk); 2193 other = unix_peer_get(sk); 2194 if (other) { 2195 if (unix_peer(other) != sk) { 2196 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2197 if (unix_recvq_full(other)) 2198 writable = 0; 2199 } 2200 sock_put(other); 2201 } 2202 2203 if (writable) 2204 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2205 else 2206 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2207 2208 return mask; 2209 } 2210 2211 #ifdef CONFIG_PROC_FS 2212 static struct sock *first_unix_socket(int *i) 2213 { 2214 for (*i = 0; *i <= UNIX_HASH_SIZE; (*i)++) { 2215 if (!hlist_empty(&unix_socket_table[*i])) 2216 return __sk_head(&unix_socket_table[*i]); 2217 } 2218 return NULL; 2219 } 2220 2221 static struct sock *next_unix_socket(int *i, struct sock *s) 2222 { 2223 struct sock *next = sk_next(s); 2224 /* More in this chain? */ 2225 if (next) 2226 return next; 2227 /* Look for next non-empty chain. */ 2228 for ((*i)++; *i <= UNIX_HASH_SIZE; (*i)++) { 2229 if (!hlist_empty(&unix_socket_table[*i])) 2230 return __sk_head(&unix_socket_table[*i]); 2231 } 2232 return NULL; 2233 } 2234 2235 struct unix_iter_state { 2236 struct seq_net_private p; 2237 int i; 2238 }; 2239 2240 static struct sock *unix_seq_idx(struct seq_file *seq, loff_t pos) 2241 { 2242 struct unix_iter_state *iter = seq->private; 2243 loff_t off = 0; 2244 struct sock *s; 2245 2246 for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) { 2247 if (sock_net(s) != seq_file_net(seq)) 2248 continue; 2249 if (off == pos) 2250 return s; 2251 ++off; 2252 } 2253 return NULL; 2254 } 2255 2256 static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2257 __acquires(unix_table_lock) 2258 { 2259 spin_lock(&unix_table_lock); 2260 return *pos ? unix_seq_idx(seq, *pos - 1) : SEQ_START_TOKEN; 2261 } 2262 2263 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2264 { 2265 struct unix_iter_state *iter = seq->private; 2266 struct sock *sk = v; 2267 ++*pos; 2268 2269 if (v == SEQ_START_TOKEN) 2270 sk = first_unix_socket(&iter->i); 2271 else 2272 sk = next_unix_socket(&iter->i, sk); 2273 while (sk && (sock_net(sk) != seq_file_net(seq))) 2274 sk = next_unix_socket(&iter->i, sk); 2275 return sk; 2276 } 2277 2278 static void unix_seq_stop(struct seq_file *seq, void *v) 2279 __releases(unix_table_lock) 2280 { 2281 spin_unlock(&unix_table_lock); 2282 } 2283 2284 static int unix_seq_show(struct seq_file *seq, void *v) 2285 { 2286 2287 if (v == SEQ_START_TOKEN) 2288 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2289 "Inode Path\n"); 2290 else { 2291 struct sock *s = v; 2292 struct unix_sock *u = unix_sk(s); 2293 unix_state_lock(s); 2294 2295 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2296 s, 2297 atomic_read(&s->sk_refcnt), 2298 0, 2299 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2300 s->sk_type, 2301 s->sk_socket ? 2302 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2303 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2304 sock_i_ino(s)); 2305 2306 if (u->addr) { 2307 int i, len; 2308 seq_putc(seq, ' '); 2309 2310 i = 0; 2311 len = u->addr->len - sizeof(short); 2312 if (!UNIX_ABSTRACT(s)) 2313 len--; 2314 else { 2315 seq_putc(seq, '@'); 2316 i++; 2317 } 2318 for ( ; i < len; i++) 2319 seq_putc(seq, u->addr->name->sun_path[i]); 2320 } 2321 unix_state_unlock(s); 2322 seq_putc(seq, '\n'); 2323 } 2324 2325 return 0; 2326 } 2327 2328 static const struct seq_operations unix_seq_ops = { 2329 .start = unix_seq_start, 2330 .next = unix_seq_next, 2331 .stop = unix_seq_stop, 2332 .show = unix_seq_show, 2333 }; 2334 2335 static int unix_seq_open(struct inode *inode, struct file *file) 2336 { 2337 return seq_open_net(inode, file, &unix_seq_ops, 2338 sizeof(struct unix_iter_state)); 2339 } 2340 2341 static const struct file_operations unix_seq_fops = { 2342 .owner = THIS_MODULE, 2343 .open = unix_seq_open, 2344 .read = seq_read, 2345 .llseek = seq_lseek, 2346 .release = seq_release_net, 2347 }; 2348 2349 #endif 2350 2351 static const struct net_proto_family unix_family_ops = { 2352 .family = PF_UNIX, 2353 .create = unix_create, 2354 .owner = THIS_MODULE, 2355 }; 2356 2357 2358 static int __net_init unix_net_init(struct net *net) 2359 { 2360 int error = -ENOMEM; 2361 2362 net->unx.sysctl_max_dgram_qlen = 10; 2363 if (unix_sysctl_register(net)) 2364 goto out; 2365 2366 #ifdef CONFIG_PROC_FS 2367 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) { 2368 unix_sysctl_unregister(net); 2369 goto out; 2370 } 2371 #endif 2372 error = 0; 2373 out: 2374 return error; 2375 } 2376 2377 static void __net_exit unix_net_exit(struct net *net) 2378 { 2379 unix_sysctl_unregister(net); 2380 proc_net_remove(net, "unix"); 2381 } 2382 2383 static struct pernet_operations unix_net_ops = { 2384 .init = unix_net_init, 2385 .exit = unix_net_exit, 2386 }; 2387 2388 static int __init af_unix_init(void) 2389 { 2390 int rc = -1; 2391 struct sk_buff *dummy_skb; 2392 2393 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb)); 2394 2395 rc = proto_register(&unix_proto, 1); 2396 if (rc != 0) { 2397 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2398 __func__); 2399 goto out; 2400 } 2401 2402 sock_register(&unix_family_ops); 2403 register_pernet_subsys(&unix_net_ops); 2404 out: 2405 return rc; 2406 } 2407 2408 static void __exit af_unix_exit(void) 2409 { 2410 sock_unregister(PF_UNIX); 2411 proto_unregister(&unix_proto); 2412 unregister_pernet_subsys(&unix_net_ops); 2413 } 2414 2415 /* Earlier than device_initcall() so that other drivers invoking 2416 request_module() don't end up in a loop when modprobe tries 2417 to use a UNIX socket. But later than subsys_initcall() because 2418 we depend on stuff initialised there */ 2419 fs_initcall(af_unix_init); 2420 module_exit(af_unix_exit); 2421 2422 MODULE_LICENSE("GPL"); 2423 MODULE_ALIAS_NETPROTO(PF_UNIX); 2424