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 #include <linux/freezer.h> 118 119 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE]; 120 EXPORT_SYMBOL_GPL(unix_socket_table); 121 DEFINE_SPINLOCK(unix_table_lock); 122 EXPORT_SYMBOL_GPL(unix_table_lock); 123 static atomic_long_t unix_nr_socks; 124 125 126 static struct hlist_head *unix_sockets_unbound(void *addr) 127 { 128 unsigned long hash = (unsigned long)addr; 129 130 hash ^= hash >> 16; 131 hash ^= hash >> 8; 132 hash %= UNIX_HASH_SIZE; 133 return &unix_socket_table[UNIX_HASH_SIZE + hash]; 134 } 135 136 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE) 137 138 #ifdef CONFIG_SECURITY_NETWORK 139 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 140 { 141 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 142 } 143 144 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 145 { 146 scm->secid = *UNIXSID(skb); 147 } 148 #else 149 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 150 { } 151 152 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 153 { } 154 #endif /* CONFIG_SECURITY_NETWORK */ 155 156 /* 157 * SMP locking strategy: 158 * hash table is protected with spinlock unix_table_lock 159 * each socket state is protected by separate spin lock. 160 */ 161 162 static inline unsigned int unix_hash_fold(__wsum n) 163 { 164 unsigned int hash = (__force unsigned int)n; 165 166 hash ^= hash>>16; 167 hash ^= hash>>8; 168 return hash&(UNIX_HASH_SIZE-1); 169 } 170 171 #define unix_peer(sk) (unix_sk(sk)->peer) 172 173 static inline int unix_our_peer(struct sock *sk, struct sock *osk) 174 { 175 return unix_peer(osk) == sk; 176 } 177 178 static inline int unix_may_send(struct sock *sk, struct sock *osk) 179 { 180 return unix_peer(osk) == NULL || unix_our_peer(sk, osk); 181 } 182 183 static inline int unix_recvq_full(struct sock const *sk) 184 { 185 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; 186 } 187 188 struct sock *unix_peer_get(struct sock *s) 189 { 190 struct sock *peer; 191 192 unix_state_lock(s); 193 peer = unix_peer(s); 194 if (peer) 195 sock_hold(peer); 196 unix_state_unlock(s); 197 return peer; 198 } 199 EXPORT_SYMBOL_GPL(unix_peer_get); 200 201 static inline void unix_release_addr(struct unix_address *addr) 202 { 203 if (atomic_dec_and_test(&addr->refcnt)) 204 kfree(addr); 205 } 206 207 /* 208 * Check unix socket name: 209 * - should be not zero length. 210 * - if started by not zero, should be NULL terminated (FS object) 211 * - if started by zero, it is abstract name. 212 */ 213 214 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp) 215 { 216 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 217 return -EINVAL; 218 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 219 return -EINVAL; 220 if (sunaddr->sun_path[0]) { 221 /* 222 * This may look like an off by one error but it is a bit more 223 * subtle. 108 is the longest valid AF_UNIX path for a binding. 224 * sun_path[108] doesn't as such exist. However in kernel space 225 * we are guaranteed that it is a valid memory location in our 226 * kernel address buffer. 227 */ 228 ((char *)sunaddr)[len] = 0; 229 len = strlen(sunaddr->sun_path)+1+sizeof(short); 230 return len; 231 } 232 233 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0)); 234 return len; 235 } 236 237 static void __unix_remove_socket(struct sock *sk) 238 { 239 sk_del_node_init(sk); 240 } 241 242 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 243 { 244 WARN_ON(!sk_unhashed(sk)); 245 sk_add_node(sk, list); 246 } 247 248 static inline void unix_remove_socket(struct sock *sk) 249 { 250 spin_lock(&unix_table_lock); 251 __unix_remove_socket(sk); 252 spin_unlock(&unix_table_lock); 253 } 254 255 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 256 { 257 spin_lock(&unix_table_lock); 258 __unix_insert_socket(list, sk); 259 spin_unlock(&unix_table_lock); 260 } 261 262 static struct sock *__unix_find_socket_byname(struct net *net, 263 struct sockaddr_un *sunname, 264 int len, int type, unsigned int hash) 265 { 266 struct sock *s; 267 268 sk_for_each(s, &unix_socket_table[hash ^ type]) { 269 struct unix_sock *u = unix_sk(s); 270 271 if (!net_eq(sock_net(s), net)) 272 continue; 273 274 if (u->addr->len == len && 275 !memcmp(u->addr->name, sunname, len)) 276 goto found; 277 } 278 s = NULL; 279 found: 280 return s; 281 } 282 283 static inline struct sock *unix_find_socket_byname(struct net *net, 284 struct sockaddr_un *sunname, 285 int len, int type, 286 unsigned int hash) 287 { 288 struct sock *s; 289 290 spin_lock(&unix_table_lock); 291 s = __unix_find_socket_byname(net, sunname, len, type, hash); 292 if (s) 293 sock_hold(s); 294 spin_unlock(&unix_table_lock); 295 return s; 296 } 297 298 static struct sock *unix_find_socket_byinode(struct inode *i) 299 { 300 struct sock *s; 301 302 spin_lock(&unix_table_lock); 303 sk_for_each(s, 304 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { 305 struct dentry *dentry = unix_sk(s)->path.dentry; 306 307 if (dentry && dentry->d_inode == i) { 308 sock_hold(s); 309 goto found; 310 } 311 } 312 s = NULL; 313 found: 314 spin_unlock(&unix_table_lock); 315 return s; 316 } 317 318 static inline int unix_writable(struct sock *sk) 319 { 320 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; 321 } 322 323 static void unix_write_space(struct sock *sk) 324 { 325 struct socket_wq *wq; 326 327 rcu_read_lock(); 328 if (unix_writable(sk)) { 329 wq = rcu_dereference(sk->sk_wq); 330 if (wq_has_sleeper(wq)) 331 wake_up_interruptible_sync_poll(&wq->wait, 332 POLLOUT | POLLWRNORM | POLLWRBAND); 333 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); 334 } 335 rcu_read_unlock(); 336 } 337 338 /* When dgram socket disconnects (or changes its peer), we clear its receive 339 * queue of packets arrived from previous peer. First, it allows to do 340 * flow control based only on wmem_alloc; second, sk connected to peer 341 * may receive messages only from that peer. */ 342 static void unix_dgram_disconnected(struct sock *sk, struct sock *other) 343 { 344 if (!skb_queue_empty(&sk->sk_receive_queue)) { 345 skb_queue_purge(&sk->sk_receive_queue); 346 wake_up_interruptible_all(&unix_sk(sk)->peer_wait); 347 348 /* If one link of bidirectional dgram pipe is disconnected, 349 * we signal error. Messages are lost. Do not make this, 350 * when peer was not connected to us. 351 */ 352 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { 353 other->sk_err = ECONNRESET; 354 other->sk_error_report(other); 355 } 356 } 357 } 358 359 static void unix_sock_destructor(struct sock *sk) 360 { 361 struct unix_sock *u = unix_sk(sk); 362 363 skb_queue_purge(&sk->sk_receive_queue); 364 365 WARN_ON(atomic_read(&sk->sk_wmem_alloc)); 366 WARN_ON(!sk_unhashed(sk)); 367 WARN_ON(sk->sk_socket); 368 if (!sock_flag(sk, SOCK_DEAD)) { 369 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk); 370 return; 371 } 372 373 if (u->addr) 374 unix_release_addr(u->addr); 375 376 atomic_long_dec(&unix_nr_socks); 377 local_bh_disable(); 378 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 379 local_bh_enable(); 380 #ifdef UNIX_REFCNT_DEBUG 381 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk, 382 atomic_long_read(&unix_nr_socks)); 383 #endif 384 } 385 386 static void unix_release_sock(struct sock *sk, int embrion) 387 { 388 struct unix_sock *u = unix_sk(sk); 389 struct path path; 390 struct sock *skpair; 391 struct sk_buff *skb; 392 int state; 393 394 unix_remove_socket(sk); 395 396 /* Clear state */ 397 unix_state_lock(sk); 398 sock_orphan(sk); 399 sk->sk_shutdown = SHUTDOWN_MASK; 400 path = u->path; 401 u->path.dentry = NULL; 402 u->path.mnt = NULL; 403 state = sk->sk_state; 404 sk->sk_state = TCP_CLOSE; 405 unix_state_unlock(sk); 406 407 wake_up_interruptible_all(&u->peer_wait); 408 409 skpair = unix_peer(sk); 410 411 if (skpair != NULL) { 412 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { 413 unix_state_lock(skpair); 414 /* No more writes */ 415 skpair->sk_shutdown = SHUTDOWN_MASK; 416 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) 417 skpair->sk_err = ECONNRESET; 418 unix_state_unlock(skpair); 419 skpair->sk_state_change(skpair); 420 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP); 421 } 422 sock_put(skpair); /* It may now die */ 423 unix_peer(sk) = NULL; 424 } 425 426 /* Try to flush out this socket. Throw out buffers at least */ 427 428 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { 429 if (state == TCP_LISTEN) 430 unix_release_sock(skb->sk, 1); 431 /* passed fds are erased in the kfree_skb hook */ 432 kfree_skb(skb); 433 } 434 435 if (path.dentry) 436 path_put(&path); 437 438 sock_put(sk); 439 440 /* ---- Socket is dead now and most probably destroyed ---- */ 441 442 /* 443 * Fixme: BSD difference: In BSD all sockets connected to us get 444 * ECONNRESET and we die on the spot. In Linux we behave 445 * like files and pipes do and wait for the last 446 * dereference. 447 * 448 * Can't we simply set sock->err? 449 * 450 * What the above comment does talk about? --ANK(980817) 451 */ 452 453 if (unix_tot_inflight) 454 unix_gc(); /* Garbage collect fds */ 455 } 456 457 static void init_peercred(struct sock *sk) 458 { 459 put_pid(sk->sk_peer_pid); 460 if (sk->sk_peer_cred) 461 put_cred(sk->sk_peer_cred); 462 sk->sk_peer_pid = get_pid(task_tgid(current)); 463 sk->sk_peer_cred = get_current_cred(); 464 } 465 466 static void copy_peercred(struct sock *sk, struct sock *peersk) 467 { 468 put_pid(sk->sk_peer_pid); 469 if (sk->sk_peer_cred) 470 put_cred(sk->sk_peer_cred); 471 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); 472 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); 473 } 474 475 static int unix_listen(struct socket *sock, int backlog) 476 { 477 int err; 478 struct sock *sk = sock->sk; 479 struct unix_sock *u = unix_sk(sk); 480 struct pid *old_pid = NULL; 481 482 err = -EOPNOTSUPP; 483 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 484 goto out; /* Only stream/seqpacket sockets accept */ 485 err = -EINVAL; 486 if (!u->addr) 487 goto out; /* No listens on an unbound socket */ 488 unix_state_lock(sk); 489 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 490 goto out_unlock; 491 if (backlog > sk->sk_max_ack_backlog) 492 wake_up_interruptible_all(&u->peer_wait); 493 sk->sk_max_ack_backlog = backlog; 494 sk->sk_state = TCP_LISTEN; 495 /* set credentials so connect can copy them */ 496 init_peercred(sk); 497 err = 0; 498 499 out_unlock: 500 unix_state_unlock(sk); 501 put_pid(old_pid); 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 void unix_set_peek_off(struct sock *sk, int val) 534 { 535 struct unix_sock *u = unix_sk(sk); 536 537 mutex_lock(&u->readlock); 538 sk->sk_peek_off = val; 539 mutex_unlock(&u->readlock); 540 } 541 542 543 static const struct proto_ops unix_stream_ops = { 544 .family = PF_UNIX, 545 .owner = THIS_MODULE, 546 .release = unix_release, 547 .bind = unix_bind, 548 .connect = unix_stream_connect, 549 .socketpair = unix_socketpair, 550 .accept = unix_accept, 551 .getname = unix_getname, 552 .poll = unix_poll, 553 .ioctl = unix_ioctl, 554 .listen = unix_listen, 555 .shutdown = unix_shutdown, 556 .setsockopt = sock_no_setsockopt, 557 .getsockopt = sock_no_getsockopt, 558 .sendmsg = unix_stream_sendmsg, 559 .recvmsg = unix_stream_recvmsg, 560 .mmap = sock_no_mmap, 561 .sendpage = sock_no_sendpage, 562 .set_peek_off = unix_set_peek_off, 563 }; 564 565 static const struct proto_ops unix_dgram_ops = { 566 .family = PF_UNIX, 567 .owner = THIS_MODULE, 568 .release = unix_release, 569 .bind = unix_bind, 570 .connect = unix_dgram_connect, 571 .socketpair = unix_socketpair, 572 .accept = sock_no_accept, 573 .getname = unix_getname, 574 .poll = unix_dgram_poll, 575 .ioctl = unix_ioctl, 576 .listen = sock_no_listen, 577 .shutdown = unix_shutdown, 578 .setsockopt = sock_no_setsockopt, 579 .getsockopt = sock_no_getsockopt, 580 .sendmsg = unix_dgram_sendmsg, 581 .recvmsg = unix_dgram_recvmsg, 582 .mmap = sock_no_mmap, 583 .sendpage = sock_no_sendpage, 584 .set_peek_off = unix_set_peek_off, 585 }; 586 587 static const struct proto_ops unix_seqpacket_ops = { 588 .family = PF_UNIX, 589 .owner = THIS_MODULE, 590 .release = unix_release, 591 .bind = unix_bind, 592 .connect = unix_stream_connect, 593 .socketpair = unix_socketpair, 594 .accept = unix_accept, 595 .getname = unix_getname, 596 .poll = unix_dgram_poll, 597 .ioctl = unix_ioctl, 598 .listen = unix_listen, 599 .shutdown = unix_shutdown, 600 .setsockopt = sock_no_setsockopt, 601 .getsockopt = sock_no_getsockopt, 602 .sendmsg = unix_seqpacket_sendmsg, 603 .recvmsg = unix_seqpacket_recvmsg, 604 .mmap = sock_no_mmap, 605 .sendpage = sock_no_sendpage, 606 .set_peek_off = unix_set_peek_off, 607 }; 608 609 static struct proto unix_proto = { 610 .name = "UNIX", 611 .owner = THIS_MODULE, 612 .obj_size = sizeof(struct unix_sock), 613 }; 614 615 /* 616 * AF_UNIX sockets do not interact with hardware, hence they 617 * dont trigger interrupts - so it's safe for them to have 618 * bh-unsafe locking for their sk_receive_queue.lock. Split off 619 * this special lock-class by reinitializing the spinlock key: 620 */ 621 static struct lock_class_key af_unix_sk_receive_queue_lock_key; 622 623 static struct sock *unix_create1(struct net *net, struct socket *sock) 624 { 625 struct sock *sk = NULL; 626 struct unix_sock *u; 627 628 atomic_long_inc(&unix_nr_socks); 629 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) 630 goto out; 631 632 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto); 633 if (!sk) 634 goto out; 635 636 sock_init_data(sock, sk); 637 lockdep_set_class(&sk->sk_receive_queue.lock, 638 &af_unix_sk_receive_queue_lock_key); 639 640 sk->sk_write_space = unix_write_space; 641 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; 642 sk->sk_destruct = unix_sock_destructor; 643 u = unix_sk(sk); 644 u->path.dentry = NULL; 645 u->path.mnt = NULL; 646 spin_lock_init(&u->lock); 647 atomic_long_set(&u->inflight, 0); 648 INIT_LIST_HEAD(&u->link); 649 mutex_init(&u->readlock); /* single task reading lock */ 650 init_waitqueue_head(&u->peer_wait); 651 unix_insert_socket(unix_sockets_unbound(sk), sk); 652 out: 653 if (sk == NULL) 654 atomic_long_dec(&unix_nr_socks); 655 else { 656 local_bh_disable(); 657 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 658 local_bh_enable(); 659 } 660 return sk; 661 } 662 663 static int unix_create(struct net *net, struct socket *sock, int protocol, 664 int kern) 665 { 666 if (protocol && protocol != PF_UNIX) 667 return -EPROTONOSUPPORT; 668 669 sock->state = SS_UNCONNECTED; 670 671 switch (sock->type) { 672 case SOCK_STREAM: 673 sock->ops = &unix_stream_ops; 674 break; 675 /* 676 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 677 * nothing uses it. 678 */ 679 case SOCK_RAW: 680 sock->type = SOCK_DGRAM; 681 case SOCK_DGRAM: 682 sock->ops = &unix_dgram_ops; 683 break; 684 case SOCK_SEQPACKET: 685 sock->ops = &unix_seqpacket_ops; 686 break; 687 default: 688 return -ESOCKTNOSUPPORT; 689 } 690 691 return unix_create1(net, sock) ? 0 : -ENOMEM; 692 } 693 694 static int unix_release(struct socket *sock) 695 { 696 struct sock *sk = sock->sk; 697 698 if (!sk) 699 return 0; 700 701 unix_release_sock(sk, 0); 702 sock->sk = NULL; 703 704 return 0; 705 } 706 707 static int unix_autobind(struct socket *sock) 708 { 709 struct sock *sk = sock->sk; 710 struct net *net = sock_net(sk); 711 struct unix_sock *u = unix_sk(sk); 712 static u32 ordernum = 1; 713 struct unix_address *addr; 714 int err; 715 unsigned int retries = 0; 716 717 mutex_lock(&u->readlock); 718 719 err = 0; 720 if (u->addr) 721 goto out; 722 723 err = -ENOMEM; 724 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 725 if (!addr) 726 goto out; 727 728 addr->name->sun_family = AF_UNIX; 729 atomic_set(&addr->refcnt, 1); 730 731 retry: 732 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 733 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0)); 734 735 spin_lock(&unix_table_lock); 736 ordernum = (ordernum+1)&0xFFFFF; 737 738 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type, 739 addr->hash)) { 740 spin_unlock(&unix_table_lock); 741 /* 742 * __unix_find_socket_byname() may take long time if many names 743 * are already in use. 744 */ 745 cond_resched(); 746 /* Give up if all names seems to be in use. */ 747 if (retries++ == 0xFFFFF) { 748 err = -ENOSPC; 749 kfree(addr); 750 goto out; 751 } 752 goto retry; 753 } 754 addr->hash ^= sk->sk_type; 755 756 __unix_remove_socket(sk); 757 u->addr = addr; 758 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 759 spin_unlock(&unix_table_lock); 760 err = 0; 761 762 out: mutex_unlock(&u->readlock); 763 return err; 764 } 765 766 static struct sock *unix_find_other(struct net *net, 767 struct sockaddr_un *sunname, int len, 768 int type, unsigned int hash, int *error) 769 { 770 struct sock *u; 771 struct path path; 772 int err = 0; 773 774 if (sunname->sun_path[0]) { 775 struct inode *inode; 776 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); 777 if (err) 778 goto fail; 779 inode = path.dentry->d_inode; 780 err = inode_permission(inode, MAY_WRITE); 781 if (err) 782 goto put_fail; 783 784 err = -ECONNREFUSED; 785 if (!S_ISSOCK(inode->i_mode)) 786 goto put_fail; 787 u = unix_find_socket_byinode(inode); 788 if (!u) 789 goto put_fail; 790 791 if (u->sk_type == type) 792 touch_atime(&path); 793 794 path_put(&path); 795 796 err = -EPROTOTYPE; 797 if (u->sk_type != type) { 798 sock_put(u); 799 goto fail; 800 } 801 } else { 802 err = -ECONNREFUSED; 803 u = unix_find_socket_byname(net, sunname, len, type, hash); 804 if (u) { 805 struct dentry *dentry; 806 dentry = unix_sk(u)->path.dentry; 807 if (dentry) 808 touch_atime(&unix_sk(u)->path); 809 } else 810 goto fail; 811 } 812 return u; 813 814 put_fail: 815 path_put(&path); 816 fail: 817 *error = err; 818 return NULL; 819 } 820 821 static int unix_mknod(const char *sun_path, umode_t mode, struct path *res) 822 { 823 struct dentry *dentry; 824 struct path path; 825 int err = 0; 826 /* 827 * Get the parent directory, calculate the hash for last 828 * component. 829 */ 830 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0); 831 err = PTR_ERR(dentry); 832 if (IS_ERR(dentry)) 833 return err; 834 835 /* 836 * All right, let's create it. 837 */ 838 err = security_path_mknod(&path, dentry, mode, 0); 839 if (!err) { 840 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0); 841 if (!err) { 842 res->mnt = mntget(path.mnt); 843 res->dentry = dget(dentry); 844 } 845 } 846 done_path_create(&path, dentry); 847 return err; 848 } 849 850 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 851 { 852 struct sock *sk = sock->sk; 853 struct net *net = sock_net(sk); 854 struct unix_sock *u = unix_sk(sk); 855 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 856 char *sun_path = sunaddr->sun_path; 857 int err; 858 unsigned int hash; 859 struct unix_address *addr; 860 struct hlist_head *list; 861 862 err = -EINVAL; 863 if (sunaddr->sun_family != AF_UNIX) 864 goto out; 865 866 if (addr_len == sizeof(short)) { 867 err = unix_autobind(sock); 868 goto out; 869 } 870 871 err = unix_mkname(sunaddr, addr_len, &hash); 872 if (err < 0) 873 goto out; 874 addr_len = err; 875 876 mutex_lock(&u->readlock); 877 878 err = -EINVAL; 879 if (u->addr) 880 goto out_up; 881 882 err = -ENOMEM; 883 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 884 if (!addr) 885 goto out_up; 886 887 memcpy(addr->name, sunaddr, addr_len); 888 addr->len = addr_len; 889 addr->hash = hash ^ sk->sk_type; 890 atomic_set(&addr->refcnt, 1); 891 892 if (sun_path[0]) { 893 struct path path; 894 umode_t mode = S_IFSOCK | 895 (SOCK_INODE(sock)->i_mode & ~current_umask()); 896 err = unix_mknod(sun_path, mode, &path); 897 if (err) { 898 if (err == -EEXIST) 899 err = -EADDRINUSE; 900 unix_release_addr(addr); 901 goto out_up; 902 } 903 addr->hash = UNIX_HASH_SIZE; 904 hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1); 905 spin_lock(&unix_table_lock); 906 u->path = path; 907 list = &unix_socket_table[hash]; 908 } else { 909 spin_lock(&unix_table_lock); 910 err = -EADDRINUSE; 911 if (__unix_find_socket_byname(net, sunaddr, addr_len, 912 sk->sk_type, hash)) { 913 unix_release_addr(addr); 914 goto out_unlock; 915 } 916 917 list = &unix_socket_table[addr->hash]; 918 } 919 920 err = 0; 921 __unix_remove_socket(sk); 922 u->addr = addr; 923 __unix_insert_socket(list, sk); 924 925 out_unlock: 926 spin_unlock(&unix_table_lock); 927 out_up: 928 mutex_unlock(&u->readlock); 929 out: 930 return err; 931 } 932 933 static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) 934 { 935 if (unlikely(sk1 == sk2) || !sk2) { 936 unix_state_lock(sk1); 937 return; 938 } 939 if (sk1 < sk2) { 940 unix_state_lock(sk1); 941 unix_state_lock_nested(sk2); 942 } else { 943 unix_state_lock(sk2); 944 unix_state_lock_nested(sk1); 945 } 946 } 947 948 static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) 949 { 950 if (unlikely(sk1 == sk2) || !sk2) { 951 unix_state_unlock(sk1); 952 return; 953 } 954 unix_state_unlock(sk1); 955 unix_state_unlock(sk2); 956 } 957 958 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 959 int alen, int flags) 960 { 961 struct sock *sk = sock->sk; 962 struct net *net = sock_net(sk); 963 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; 964 struct sock *other; 965 unsigned int hash; 966 int err; 967 968 if (addr->sa_family != AF_UNSPEC) { 969 err = unix_mkname(sunaddr, alen, &hash); 970 if (err < 0) 971 goto out; 972 alen = err; 973 974 if (test_bit(SOCK_PASSCRED, &sock->flags) && 975 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 976 goto out; 977 978 restart: 979 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); 980 if (!other) 981 goto out; 982 983 unix_state_double_lock(sk, other); 984 985 /* Apparently VFS overslept socket death. Retry. */ 986 if (sock_flag(other, SOCK_DEAD)) { 987 unix_state_double_unlock(sk, other); 988 sock_put(other); 989 goto restart; 990 } 991 992 err = -EPERM; 993 if (!unix_may_send(sk, other)) 994 goto out_unlock; 995 996 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 997 if (err) 998 goto out_unlock; 999 1000 } else { 1001 /* 1002 * 1003.1g breaking connected state with AF_UNSPEC 1003 */ 1004 other = NULL; 1005 unix_state_double_lock(sk, other); 1006 } 1007 1008 /* 1009 * If it was connected, reconnect. 1010 */ 1011 if (unix_peer(sk)) { 1012 struct sock *old_peer = unix_peer(sk); 1013 unix_peer(sk) = other; 1014 unix_state_double_unlock(sk, other); 1015 1016 if (other != old_peer) 1017 unix_dgram_disconnected(sk, old_peer); 1018 sock_put(old_peer); 1019 } else { 1020 unix_peer(sk) = other; 1021 unix_state_double_unlock(sk, other); 1022 } 1023 return 0; 1024 1025 out_unlock: 1026 unix_state_double_unlock(sk, other); 1027 sock_put(other); 1028 out: 1029 return err; 1030 } 1031 1032 static long unix_wait_for_peer(struct sock *other, long timeo) 1033 { 1034 struct unix_sock *u = unix_sk(other); 1035 int sched; 1036 DEFINE_WAIT(wait); 1037 1038 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 1039 1040 sched = !sock_flag(other, SOCK_DEAD) && 1041 !(other->sk_shutdown & RCV_SHUTDOWN) && 1042 unix_recvq_full(other); 1043 1044 unix_state_unlock(other); 1045 1046 if (sched) 1047 timeo = schedule_timeout(timeo); 1048 1049 finish_wait(&u->peer_wait, &wait); 1050 return timeo; 1051 } 1052 1053 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 1054 int addr_len, int flags) 1055 { 1056 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 1057 struct sock *sk = sock->sk; 1058 struct net *net = sock_net(sk); 1059 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 1060 struct sock *newsk = NULL; 1061 struct sock *other = NULL; 1062 struct sk_buff *skb = NULL; 1063 unsigned int hash; 1064 int st; 1065 int err; 1066 long timeo; 1067 1068 err = unix_mkname(sunaddr, addr_len, &hash); 1069 if (err < 0) 1070 goto out; 1071 addr_len = err; 1072 1073 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && 1074 (err = unix_autobind(sock)) != 0) 1075 goto out; 1076 1077 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 1078 1079 /* First of all allocate resources. 1080 If we will make it after state is locked, 1081 we will have to recheck all again in any case. 1082 */ 1083 1084 err = -ENOMEM; 1085 1086 /* create new sock for complete connection */ 1087 newsk = unix_create1(sock_net(sk), NULL); 1088 if (newsk == NULL) 1089 goto out; 1090 1091 /* Allocate skb for sending to listening sock */ 1092 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 1093 if (skb == NULL) 1094 goto out; 1095 1096 restart: 1097 /* Find listening sock. */ 1098 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); 1099 if (!other) 1100 goto out; 1101 1102 /* Latch state of peer */ 1103 unix_state_lock(other); 1104 1105 /* Apparently VFS overslept socket death. Retry. */ 1106 if (sock_flag(other, SOCK_DEAD)) { 1107 unix_state_unlock(other); 1108 sock_put(other); 1109 goto restart; 1110 } 1111 1112 err = -ECONNREFUSED; 1113 if (other->sk_state != TCP_LISTEN) 1114 goto out_unlock; 1115 if (other->sk_shutdown & RCV_SHUTDOWN) 1116 goto out_unlock; 1117 1118 if (unix_recvq_full(other)) { 1119 err = -EAGAIN; 1120 if (!timeo) 1121 goto out_unlock; 1122 1123 timeo = unix_wait_for_peer(other, timeo); 1124 1125 err = sock_intr_errno(timeo); 1126 if (signal_pending(current)) 1127 goto out; 1128 sock_put(other); 1129 goto restart; 1130 } 1131 1132 /* Latch our state. 1133 1134 It is tricky place. We need to grab our state lock and cannot 1135 drop lock on peer. It is dangerous because deadlock is 1136 possible. Connect to self case and simultaneous 1137 attempt to connect are eliminated by checking socket 1138 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1139 check this before attempt to grab lock. 1140 1141 Well, and we have to recheck the state after socket locked. 1142 */ 1143 st = sk->sk_state; 1144 1145 switch (st) { 1146 case TCP_CLOSE: 1147 /* This is ok... continue with connect */ 1148 break; 1149 case TCP_ESTABLISHED: 1150 /* Socket is already connected */ 1151 err = -EISCONN; 1152 goto out_unlock; 1153 default: 1154 err = -EINVAL; 1155 goto out_unlock; 1156 } 1157 1158 unix_state_lock_nested(sk); 1159 1160 if (sk->sk_state != st) { 1161 unix_state_unlock(sk); 1162 unix_state_unlock(other); 1163 sock_put(other); 1164 goto restart; 1165 } 1166 1167 err = security_unix_stream_connect(sk, other, newsk); 1168 if (err) { 1169 unix_state_unlock(sk); 1170 goto out_unlock; 1171 } 1172 1173 /* The way is open! Fastly set all the necessary fields... */ 1174 1175 sock_hold(sk); 1176 unix_peer(newsk) = sk; 1177 newsk->sk_state = TCP_ESTABLISHED; 1178 newsk->sk_type = sk->sk_type; 1179 init_peercred(newsk); 1180 newu = unix_sk(newsk); 1181 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); 1182 otheru = unix_sk(other); 1183 1184 /* copy address information from listening to new sock*/ 1185 if (otheru->addr) { 1186 atomic_inc(&otheru->addr->refcnt); 1187 newu->addr = otheru->addr; 1188 } 1189 if (otheru->path.dentry) { 1190 path_get(&otheru->path); 1191 newu->path = otheru->path; 1192 } 1193 1194 /* Set credentials */ 1195 copy_peercred(sk, other); 1196 1197 sock->state = SS_CONNECTED; 1198 sk->sk_state = TCP_ESTABLISHED; 1199 sock_hold(newsk); 1200 1201 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1202 unix_peer(sk) = newsk; 1203 1204 unix_state_unlock(sk); 1205 1206 /* take ten and and send info to listening sock */ 1207 spin_lock(&other->sk_receive_queue.lock); 1208 __skb_queue_tail(&other->sk_receive_queue, skb); 1209 spin_unlock(&other->sk_receive_queue.lock); 1210 unix_state_unlock(other); 1211 other->sk_data_ready(other, 0); 1212 sock_put(other); 1213 return 0; 1214 1215 out_unlock: 1216 if (other) 1217 unix_state_unlock(other); 1218 1219 out: 1220 kfree_skb(skb); 1221 if (newsk) 1222 unix_release_sock(newsk, 0); 1223 if (other) 1224 sock_put(other); 1225 return err; 1226 } 1227 1228 static int unix_socketpair(struct socket *socka, struct socket *sockb) 1229 { 1230 struct sock *ska = socka->sk, *skb = sockb->sk; 1231 1232 /* Join our sockets back to back */ 1233 sock_hold(ska); 1234 sock_hold(skb); 1235 unix_peer(ska) = skb; 1236 unix_peer(skb) = ska; 1237 init_peercred(ska); 1238 init_peercred(skb); 1239 1240 if (ska->sk_type != SOCK_DGRAM) { 1241 ska->sk_state = TCP_ESTABLISHED; 1242 skb->sk_state = TCP_ESTABLISHED; 1243 socka->state = SS_CONNECTED; 1244 sockb->state = SS_CONNECTED; 1245 } 1246 return 0; 1247 } 1248 1249 static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1250 { 1251 struct sock *sk = sock->sk; 1252 struct sock *tsk; 1253 struct sk_buff *skb; 1254 int err; 1255 1256 err = -EOPNOTSUPP; 1257 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 1258 goto out; 1259 1260 err = -EINVAL; 1261 if (sk->sk_state != TCP_LISTEN) 1262 goto out; 1263 1264 /* If socket state is TCP_LISTEN it cannot change (for now...), 1265 * so that no locks are necessary. 1266 */ 1267 1268 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1269 if (!skb) { 1270 /* This means receive shutdown. */ 1271 if (err == 0) 1272 err = -EINVAL; 1273 goto out; 1274 } 1275 1276 tsk = skb->sk; 1277 skb_free_datagram(sk, skb); 1278 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1279 1280 /* attach accepted sock to socket */ 1281 unix_state_lock(tsk); 1282 newsock->state = SS_CONNECTED; 1283 sock_graft(tsk, newsock); 1284 unix_state_unlock(tsk); 1285 return 0; 1286 1287 out: 1288 return err; 1289 } 1290 1291 1292 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1293 { 1294 struct sock *sk = sock->sk; 1295 struct unix_sock *u; 1296 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); 1297 int err = 0; 1298 1299 if (peer) { 1300 sk = unix_peer_get(sk); 1301 1302 err = -ENOTCONN; 1303 if (!sk) 1304 goto out; 1305 err = 0; 1306 } else { 1307 sock_hold(sk); 1308 } 1309 1310 u = unix_sk(sk); 1311 unix_state_lock(sk); 1312 if (!u->addr) { 1313 sunaddr->sun_family = AF_UNIX; 1314 sunaddr->sun_path[0] = 0; 1315 *uaddr_len = sizeof(short); 1316 } else { 1317 struct unix_address *addr = u->addr; 1318 1319 *uaddr_len = addr->len; 1320 memcpy(sunaddr, addr->name, *uaddr_len); 1321 } 1322 unix_state_unlock(sk); 1323 sock_put(sk); 1324 out: 1325 return err; 1326 } 1327 1328 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1329 { 1330 int i; 1331 1332 scm->fp = UNIXCB(skb).fp; 1333 UNIXCB(skb).fp = NULL; 1334 1335 for (i = scm->fp->count-1; i >= 0; i--) 1336 unix_notinflight(scm->fp->fp[i]); 1337 } 1338 1339 static void unix_destruct_scm(struct sk_buff *skb) 1340 { 1341 struct scm_cookie scm; 1342 memset(&scm, 0, sizeof(scm)); 1343 scm.pid = UNIXCB(skb).pid; 1344 if (UNIXCB(skb).fp) 1345 unix_detach_fds(&scm, skb); 1346 1347 /* Alas, it calls VFS */ 1348 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1349 scm_destroy(&scm); 1350 sock_wfree(skb); 1351 } 1352 1353 #define MAX_RECURSION_LEVEL 4 1354 1355 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1356 { 1357 int i; 1358 unsigned char max_level = 0; 1359 int unix_sock_count = 0; 1360 1361 for (i = scm->fp->count - 1; i >= 0; i--) { 1362 struct sock *sk = unix_get_socket(scm->fp->fp[i]); 1363 1364 if (sk) { 1365 unix_sock_count++; 1366 max_level = max(max_level, 1367 unix_sk(sk)->recursion_level); 1368 } 1369 } 1370 if (unlikely(max_level > MAX_RECURSION_LEVEL)) 1371 return -ETOOMANYREFS; 1372 1373 /* 1374 * Need to duplicate file references for the sake of garbage 1375 * collection. Otherwise a socket in the fps might become a 1376 * candidate for GC while the skb is not yet queued. 1377 */ 1378 UNIXCB(skb).fp = scm_fp_dup(scm->fp); 1379 if (!UNIXCB(skb).fp) 1380 return -ENOMEM; 1381 1382 if (unix_sock_count) { 1383 for (i = scm->fp->count - 1; i >= 0; i--) 1384 unix_inflight(scm->fp->fp[i]); 1385 } 1386 return max_level; 1387 } 1388 1389 static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) 1390 { 1391 int err = 0; 1392 1393 UNIXCB(skb).pid = get_pid(scm->pid); 1394 UNIXCB(skb).uid = scm->creds.uid; 1395 UNIXCB(skb).gid = scm->creds.gid; 1396 UNIXCB(skb).fp = NULL; 1397 if (scm->fp && send_fds) 1398 err = unix_attach_fds(scm, skb); 1399 1400 skb->destructor = unix_destruct_scm; 1401 return err; 1402 } 1403 1404 /* 1405 * Some apps rely on write() giving SCM_CREDENTIALS 1406 * We include credentials if source or destination socket 1407 * asserted SOCK_PASSCRED. 1408 */ 1409 static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, 1410 const struct sock *other) 1411 { 1412 if (UNIXCB(skb).pid) 1413 return; 1414 if (test_bit(SOCK_PASSCRED, &sock->flags) || 1415 !other->sk_socket || 1416 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { 1417 UNIXCB(skb).pid = get_pid(task_tgid(current)); 1418 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); 1419 } 1420 } 1421 1422 /* 1423 * Send AF_UNIX data. 1424 */ 1425 1426 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1427 struct msghdr *msg, size_t len) 1428 { 1429 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1430 struct sock *sk = sock->sk; 1431 struct net *net = sock_net(sk); 1432 struct unix_sock *u = unix_sk(sk); 1433 struct sockaddr_un *sunaddr = msg->msg_name; 1434 struct sock *other = NULL; 1435 int namelen = 0; /* fake GCC */ 1436 int err; 1437 unsigned int hash; 1438 struct sk_buff *skb; 1439 long timeo; 1440 struct scm_cookie tmp_scm; 1441 int max_level; 1442 int data_len = 0; 1443 1444 if (NULL == siocb->scm) 1445 siocb->scm = &tmp_scm; 1446 wait_for_unix_gc(); 1447 err = scm_send(sock, msg, siocb->scm, false); 1448 if (err < 0) 1449 return err; 1450 1451 err = -EOPNOTSUPP; 1452 if (msg->msg_flags&MSG_OOB) 1453 goto out; 1454 1455 if (msg->msg_namelen) { 1456 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1457 if (err < 0) 1458 goto out; 1459 namelen = err; 1460 } else { 1461 sunaddr = NULL; 1462 err = -ENOTCONN; 1463 other = unix_peer_get(sk); 1464 if (!other) 1465 goto out; 1466 } 1467 1468 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr 1469 && (err = unix_autobind(sock)) != 0) 1470 goto out; 1471 1472 err = -EMSGSIZE; 1473 if (len > sk->sk_sndbuf - 32) 1474 goto out; 1475 1476 if (len > SKB_MAX_ALLOC) 1477 data_len = min_t(size_t, 1478 len - SKB_MAX_ALLOC, 1479 MAX_SKB_FRAGS * PAGE_SIZE); 1480 1481 skb = sock_alloc_send_pskb(sk, len - data_len, data_len, 1482 msg->msg_flags & MSG_DONTWAIT, &err); 1483 if (skb == NULL) 1484 goto out; 1485 1486 err = unix_scm_to_skb(siocb->scm, skb, true); 1487 if (err < 0) 1488 goto out_free; 1489 max_level = err + 1; 1490 unix_get_secdata(siocb->scm, skb); 1491 1492 skb_put(skb, len - data_len); 1493 skb->data_len = data_len; 1494 skb->len = len; 1495 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len); 1496 if (err) 1497 goto out_free; 1498 1499 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1500 1501 restart: 1502 if (!other) { 1503 err = -ECONNRESET; 1504 if (sunaddr == NULL) 1505 goto out_free; 1506 1507 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1508 hash, &err); 1509 if (other == NULL) 1510 goto out_free; 1511 } 1512 1513 if (sk_filter(other, skb) < 0) { 1514 /* Toss the packet but do not return any error to the sender */ 1515 err = len; 1516 goto out_free; 1517 } 1518 1519 unix_state_lock(other); 1520 err = -EPERM; 1521 if (!unix_may_send(sk, other)) 1522 goto out_unlock; 1523 1524 if (sock_flag(other, SOCK_DEAD)) { 1525 /* 1526 * Check with 1003.1g - what should 1527 * datagram error 1528 */ 1529 unix_state_unlock(other); 1530 sock_put(other); 1531 1532 err = 0; 1533 unix_state_lock(sk); 1534 if (unix_peer(sk) == other) { 1535 unix_peer(sk) = NULL; 1536 unix_state_unlock(sk); 1537 1538 unix_dgram_disconnected(sk, other); 1539 sock_put(other); 1540 err = -ECONNREFUSED; 1541 } else { 1542 unix_state_unlock(sk); 1543 } 1544 1545 other = NULL; 1546 if (err) 1547 goto out_free; 1548 goto restart; 1549 } 1550 1551 err = -EPIPE; 1552 if (other->sk_shutdown & RCV_SHUTDOWN) 1553 goto out_unlock; 1554 1555 if (sk->sk_type != SOCK_SEQPACKET) { 1556 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1557 if (err) 1558 goto out_unlock; 1559 } 1560 1561 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1562 if (!timeo) { 1563 err = -EAGAIN; 1564 goto out_unlock; 1565 } 1566 1567 timeo = unix_wait_for_peer(other, timeo); 1568 1569 err = sock_intr_errno(timeo); 1570 if (signal_pending(current)) 1571 goto out_free; 1572 1573 goto restart; 1574 } 1575 1576 if (sock_flag(other, SOCK_RCVTSTAMP)) 1577 __net_timestamp(skb); 1578 maybe_add_creds(skb, sock, other); 1579 skb_queue_tail(&other->sk_receive_queue, skb); 1580 if (max_level > unix_sk(other)->recursion_level) 1581 unix_sk(other)->recursion_level = max_level; 1582 unix_state_unlock(other); 1583 other->sk_data_ready(other, len); 1584 sock_put(other); 1585 scm_destroy(siocb->scm); 1586 return len; 1587 1588 out_unlock: 1589 unix_state_unlock(other); 1590 out_free: 1591 kfree_skb(skb); 1592 out: 1593 if (other) 1594 sock_put(other); 1595 scm_destroy(siocb->scm); 1596 return err; 1597 } 1598 1599 1600 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1601 struct msghdr *msg, size_t len) 1602 { 1603 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1604 struct sock *sk = sock->sk; 1605 struct sock *other = NULL; 1606 int err, size; 1607 struct sk_buff *skb; 1608 int sent = 0; 1609 struct scm_cookie tmp_scm; 1610 bool fds_sent = false; 1611 int max_level; 1612 1613 if (NULL == siocb->scm) 1614 siocb->scm = &tmp_scm; 1615 wait_for_unix_gc(); 1616 err = scm_send(sock, msg, siocb->scm, false); 1617 if (err < 0) 1618 return err; 1619 1620 err = -EOPNOTSUPP; 1621 if (msg->msg_flags&MSG_OOB) 1622 goto out_err; 1623 1624 if (msg->msg_namelen) { 1625 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1626 goto out_err; 1627 } else { 1628 err = -ENOTCONN; 1629 other = unix_peer(sk); 1630 if (!other) 1631 goto out_err; 1632 } 1633 1634 if (sk->sk_shutdown & SEND_SHUTDOWN) 1635 goto pipe_err; 1636 1637 while (sent < len) { 1638 /* 1639 * Optimisation for the fact that under 0.01% of X 1640 * messages typically need breaking up. 1641 */ 1642 1643 size = len-sent; 1644 1645 /* Keep two messages in the pipe so it schedules better */ 1646 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1647 size = (sk->sk_sndbuf >> 1) - 64; 1648 1649 if (size > SKB_MAX_ALLOC) 1650 size = SKB_MAX_ALLOC; 1651 1652 /* 1653 * Grab a buffer 1654 */ 1655 1656 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT, 1657 &err); 1658 1659 if (skb == NULL) 1660 goto out_err; 1661 1662 /* 1663 * If you pass two values to the sock_alloc_send_skb 1664 * it tries to grab the large buffer with GFP_NOFS 1665 * (which can fail easily), and if it fails grab the 1666 * fallback size buffer which is under a page and will 1667 * succeed. [Alan] 1668 */ 1669 size = min_t(int, size, skb_tailroom(skb)); 1670 1671 1672 /* Only send the fds in the first buffer */ 1673 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1674 if (err < 0) { 1675 kfree_skb(skb); 1676 goto out_err; 1677 } 1678 max_level = err + 1; 1679 fds_sent = true; 1680 1681 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size); 1682 if (err) { 1683 kfree_skb(skb); 1684 goto out_err; 1685 } 1686 1687 unix_state_lock(other); 1688 1689 if (sock_flag(other, SOCK_DEAD) || 1690 (other->sk_shutdown & RCV_SHUTDOWN)) 1691 goto pipe_err_free; 1692 1693 maybe_add_creds(skb, sock, other); 1694 skb_queue_tail(&other->sk_receive_queue, skb); 1695 if (max_level > unix_sk(other)->recursion_level) 1696 unix_sk(other)->recursion_level = max_level; 1697 unix_state_unlock(other); 1698 other->sk_data_ready(other, size); 1699 sent += size; 1700 } 1701 1702 scm_destroy(siocb->scm); 1703 siocb->scm = NULL; 1704 1705 return sent; 1706 1707 pipe_err_free: 1708 unix_state_unlock(other); 1709 kfree_skb(skb); 1710 pipe_err: 1711 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1712 send_sig(SIGPIPE, current, 0); 1713 err = -EPIPE; 1714 out_err: 1715 scm_destroy(siocb->scm); 1716 siocb->scm = NULL; 1717 return sent ? : err; 1718 } 1719 1720 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1721 struct msghdr *msg, size_t len) 1722 { 1723 int err; 1724 struct sock *sk = sock->sk; 1725 1726 err = sock_error(sk); 1727 if (err) 1728 return err; 1729 1730 if (sk->sk_state != TCP_ESTABLISHED) 1731 return -ENOTCONN; 1732 1733 if (msg->msg_namelen) 1734 msg->msg_namelen = 0; 1735 1736 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1737 } 1738 1739 static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1740 struct msghdr *msg, size_t size, 1741 int flags) 1742 { 1743 struct sock *sk = sock->sk; 1744 1745 if (sk->sk_state != TCP_ESTABLISHED) 1746 return -ENOTCONN; 1747 1748 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1749 } 1750 1751 static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1752 { 1753 struct unix_sock *u = unix_sk(sk); 1754 1755 msg->msg_namelen = 0; 1756 if (u->addr) { 1757 msg->msg_namelen = u->addr->len; 1758 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1759 } 1760 } 1761 1762 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1763 struct msghdr *msg, size_t size, 1764 int flags) 1765 { 1766 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1767 struct scm_cookie tmp_scm; 1768 struct sock *sk = sock->sk; 1769 struct unix_sock *u = unix_sk(sk); 1770 int noblock = flags & MSG_DONTWAIT; 1771 struct sk_buff *skb; 1772 int err; 1773 int peeked, skip; 1774 1775 err = -EOPNOTSUPP; 1776 if (flags&MSG_OOB) 1777 goto out; 1778 1779 msg->msg_namelen = 0; 1780 1781 err = mutex_lock_interruptible(&u->readlock); 1782 if (err) { 1783 err = sock_intr_errno(sock_rcvtimeo(sk, noblock)); 1784 goto out; 1785 } 1786 1787 skip = sk_peek_offset(sk, flags); 1788 1789 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); 1790 if (!skb) { 1791 unix_state_lock(sk); 1792 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1793 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1794 (sk->sk_shutdown & RCV_SHUTDOWN)) 1795 err = 0; 1796 unix_state_unlock(sk); 1797 goto out_unlock; 1798 } 1799 1800 wake_up_interruptible_sync_poll(&u->peer_wait, 1801 POLLOUT | POLLWRNORM | POLLWRBAND); 1802 1803 if (msg->msg_name) 1804 unix_copy_addr(msg, skb->sk); 1805 1806 if (size > skb->len - skip) 1807 size = skb->len - skip; 1808 else if (size < skb->len - skip) 1809 msg->msg_flags |= MSG_TRUNC; 1810 1811 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size); 1812 if (err) 1813 goto out_free; 1814 1815 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1816 __sock_recv_timestamp(msg, sk, skb); 1817 1818 if (!siocb->scm) { 1819 siocb->scm = &tmp_scm; 1820 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1821 } 1822 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 1823 unix_set_secdata(siocb->scm, skb); 1824 1825 if (!(flags & MSG_PEEK)) { 1826 if (UNIXCB(skb).fp) 1827 unix_detach_fds(siocb->scm, skb); 1828 1829 sk_peek_offset_bwd(sk, skb->len); 1830 } else { 1831 /* It is questionable: on PEEK we could: 1832 - do not return fds - good, but too simple 8) 1833 - return fds, and do not return them on read (old strategy, 1834 apparently wrong) 1835 - clone fds (I chose it for now, it is the most universal 1836 solution) 1837 1838 POSIX 1003.1g does not actually define this clearly 1839 at all. POSIX 1003.1g doesn't define a lot of things 1840 clearly however! 1841 1842 */ 1843 1844 sk_peek_offset_fwd(sk, size); 1845 1846 if (UNIXCB(skb).fp) 1847 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1848 } 1849 err = (flags & MSG_TRUNC) ? skb->len - skip : size; 1850 1851 scm_recv(sock, msg, siocb->scm, flags); 1852 1853 out_free: 1854 skb_free_datagram(sk, skb); 1855 out_unlock: 1856 mutex_unlock(&u->readlock); 1857 out: 1858 return err; 1859 } 1860 1861 /* 1862 * Sleep until more data has arrived. But check for races.. 1863 */ 1864 static long unix_stream_data_wait(struct sock *sk, long timeo, 1865 struct sk_buff *last) 1866 { 1867 DEFINE_WAIT(wait); 1868 1869 unix_state_lock(sk); 1870 1871 for (;;) { 1872 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1873 1874 if (skb_peek_tail(&sk->sk_receive_queue) != last || 1875 sk->sk_err || 1876 (sk->sk_shutdown & RCV_SHUTDOWN) || 1877 signal_pending(current) || 1878 !timeo) 1879 break; 1880 1881 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1882 unix_state_unlock(sk); 1883 timeo = freezable_schedule_timeout(timeo); 1884 unix_state_lock(sk); 1885 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1886 } 1887 1888 finish_wait(sk_sleep(sk), &wait); 1889 unix_state_unlock(sk); 1890 return timeo; 1891 } 1892 1893 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1894 struct msghdr *msg, size_t size, 1895 int flags) 1896 { 1897 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1898 struct scm_cookie tmp_scm; 1899 struct sock *sk = sock->sk; 1900 struct unix_sock *u = unix_sk(sk); 1901 struct sockaddr_un *sunaddr = msg->msg_name; 1902 int copied = 0; 1903 int check_creds = 0; 1904 int target; 1905 int err = 0; 1906 long timeo; 1907 int skip; 1908 1909 err = -EINVAL; 1910 if (sk->sk_state != TCP_ESTABLISHED) 1911 goto out; 1912 1913 err = -EOPNOTSUPP; 1914 if (flags&MSG_OOB) 1915 goto out; 1916 1917 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1918 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1919 1920 msg->msg_namelen = 0; 1921 1922 /* Lock the socket to prevent queue disordering 1923 * while sleeps in memcpy_tomsg 1924 */ 1925 1926 if (!siocb->scm) { 1927 siocb->scm = &tmp_scm; 1928 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1929 } 1930 1931 err = mutex_lock_interruptible(&u->readlock); 1932 if (err) { 1933 err = sock_intr_errno(timeo); 1934 goto out; 1935 } 1936 1937 do { 1938 int chunk; 1939 struct sk_buff *skb, *last; 1940 1941 unix_state_lock(sk); 1942 last = skb = skb_peek(&sk->sk_receive_queue); 1943 again: 1944 if (skb == NULL) { 1945 unix_sk(sk)->recursion_level = 0; 1946 if (copied >= target) 1947 goto unlock; 1948 1949 /* 1950 * POSIX 1003.1g mandates this order. 1951 */ 1952 1953 err = sock_error(sk); 1954 if (err) 1955 goto unlock; 1956 if (sk->sk_shutdown & RCV_SHUTDOWN) 1957 goto unlock; 1958 1959 unix_state_unlock(sk); 1960 err = -EAGAIN; 1961 if (!timeo) 1962 break; 1963 mutex_unlock(&u->readlock); 1964 1965 timeo = unix_stream_data_wait(sk, timeo, last); 1966 1967 if (signal_pending(current) 1968 || mutex_lock_interruptible(&u->readlock)) { 1969 err = sock_intr_errno(timeo); 1970 goto out; 1971 } 1972 1973 continue; 1974 unlock: 1975 unix_state_unlock(sk); 1976 break; 1977 } 1978 1979 skip = sk_peek_offset(sk, flags); 1980 while (skip >= skb->len) { 1981 skip -= skb->len; 1982 last = skb; 1983 skb = skb_peek_next(skb, &sk->sk_receive_queue); 1984 if (!skb) 1985 goto again; 1986 } 1987 1988 unix_state_unlock(sk); 1989 1990 if (check_creds) { 1991 /* Never glue messages from different writers */ 1992 if ((UNIXCB(skb).pid != siocb->scm->pid) || 1993 !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) || 1994 !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid)) 1995 break; 1996 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { 1997 /* Copy credentials */ 1998 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 1999 check_creds = 1; 2000 } 2001 2002 /* Copy address just once */ 2003 if (sunaddr) { 2004 unix_copy_addr(msg, skb->sk); 2005 sunaddr = NULL; 2006 } 2007 2008 chunk = min_t(unsigned int, skb->len - skip, size); 2009 if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) { 2010 if (copied == 0) 2011 copied = -EFAULT; 2012 break; 2013 } 2014 copied += chunk; 2015 size -= chunk; 2016 2017 /* Mark read part of skb as used */ 2018 if (!(flags & MSG_PEEK)) { 2019 skb_pull(skb, chunk); 2020 2021 sk_peek_offset_bwd(sk, chunk); 2022 2023 if (UNIXCB(skb).fp) 2024 unix_detach_fds(siocb->scm, skb); 2025 2026 if (skb->len) 2027 break; 2028 2029 skb_unlink(skb, &sk->sk_receive_queue); 2030 consume_skb(skb); 2031 2032 if (siocb->scm->fp) 2033 break; 2034 } else { 2035 /* It is questionable, see note in unix_dgram_recvmsg. 2036 */ 2037 if (UNIXCB(skb).fp) 2038 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2039 2040 sk_peek_offset_fwd(sk, chunk); 2041 2042 break; 2043 } 2044 } while (size); 2045 2046 mutex_unlock(&u->readlock); 2047 scm_recv(sock, msg, siocb->scm, flags); 2048 out: 2049 return copied ? : err; 2050 } 2051 2052 static int unix_shutdown(struct socket *sock, int mode) 2053 { 2054 struct sock *sk = sock->sk; 2055 struct sock *other; 2056 2057 if (mode < SHUT_RD || mode > SHUT_RDWR) 2058 return -EINVAL; 2059 /* This maps: 2060 * SHUT_RD (0) -> RCV_SHUTDOWN (1) 2061 * SHUT_WR (1) -> SEND_SHUTDOWN (2) 2062 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3) 2063 */ 2064 ++mode; 2065 2066 unix_state_lock(sk); 2067 sk->sk_shutdown |= mode; 2068 other = unix_peer(sk); 2069 if (other) 2070 sock_hold(other); 2071 unix_state_unlock(sk); 2072 sk->sk_state_change(sk); 2073 2074 if (other && 2075 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2076 2077 int peer_mode = 0; 2078 2079 if (mode&RCV_SHUTDOWN) 2080 peer_mode |= SEND_SHUTDOWN; 2081 if (mode&SEND_SHUTDOWN) 2082 peer_mode |= RCV_SHUTDOWN; 2083 unix_state_lock(other); 2084 other->sk_shutdown |= peer_mode; 2085 unix_state_unlock(other); 2086 other->sk_state_change(other); 2087 if (peer_mode == SHUTDOWN_MASK) 2088 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2089 else if (peer_mode & RCV_SHUTDOWN) 2090 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2091 } 2092 if (other) 2093 sock_put(other); 2094 2095 return 0; 2096 } 2097 2098 long unix_inq_len(struct sock *sk) 2099 { 2100 struct sk_buff *skb; 2101 long amount = 0; 2102 2103 if (sk->sk_state == TCP_LISTEN) 2104 return -EINVAL; 2105 2106 spin_lock(&sk->sk_receive_queue.lock); 2107 if (sk->sk_type == SOCK_STREAM || 2108 sk->sk_type == SOCK_SEQPACKET) { 2109 skb_queue_walk(&sk->sk_receive_queue, skb) 2110 amount += skb->len; 2111 } else { 2112 skb = skb_peek(&sk->sk_receive_queue); 2113 if (skb) 2114 amount = skb->len; 2115 } 2116 spin_unlock(&sk->sk_receive_queue.lock); 2117 2118 return amount; 2119 } 2120 EXPORT_SYMBOL_GPL(unix_inq_len); 2121 2122 long unix_outq_len(struct sock *sk) 2123 { 2124 return sk_wmem_alloc_get(sk); 2125 } 2126 EXPORT_SYMBOL_GPL(unix_outq_len); 2127 2128 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2129 { 2130 struct sock *sk = sock->sk; 2131 long amount = 0; 2132 int err; 2133 2134 switch (cmd) { 2135 case SIOCOUTQ: 2136 amount = unix_outq_len(sk); 2137 err = put_user(amount, (int __user *)arg); 2138 break; 2139 case SIOCINQ: 2140 amount = unix_inq_len(sk); 2141 if (amount < 0) 2142 err = amount; 2143 else 2144 err = put_user(amount, (int __user *)arg); 2145 break; 2146 default: 2147 err = -ENOIOCTLCMD; 2148 break; 2149 } 2150 return err; 2151 } 2152 2153 static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2154 { 2155 struct sock *sk = sock->sk; 2156 unsigned int mask; 2157 2158 sock_poll_wait(file, sk_sleep(sk), wait); 2159 mask = 0; 2160 2161 /* exceptional events? */ 2162 if (sk->sk_err) 2163 mask |= POLLERR; 2164 if (sk->sk_shutdown == SHUTDOWN_MASK) 2165 mask |= POLLHUP; 2166 if (sk->sk_shutdown & RCV_SHUTDOWN) 2167 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2168 2169 /* readable? */ 2170 if (!skb_queue_empty(&sk->sk_receive_queue)) 2171 mask |= POLLIN | POLLRDNORM; 2172 2173 /* Connection-based need to check for termination and startup */ 2174 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2175 sk->sk_state == TCP_CLOSE) 2176 mask |= POLLHUP; 2177 2178 /* 2179 * we set writable also when the other side has shut down the 2180 * connection. This prevents stuck sockets. 2181 */ 2182 if (unix_writable(sk)) 2183 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2184 2185 return mask; 2186 } 2187 2188 static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2189 poll_table *wait) 2190 { 2191 struct sock *sk = sock->sk, *other; 2192 unsigned int mask, writable; 2193 2194 sock_poll_wait(file, sk_sleep(sk), wait); 2195 mask = 0; 2196 2197 /* exceptional events? */ 2198 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2199 mask |= POLLERR | 2200 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0); 2201 2202 if (sk->sk_shutdown & RCV_SHUTDOWN) 2203 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2204 if (sk->sk_shutdown == SHUTDOWN_MASK) 2205 mask |= POLLHUP; 2206 2207 /* readable? */ 2208 if (!skb_queue_empty(&sk->sk_receive_queue)) 2209 mask |= POLLIN | POLLRDNORM; 2210 2211 /* Connection-based need to check for termination and startup */ 2212 if (sk->sk_type == SOCK_SEQPACKET) { 2213 if (sk->sk_state == TCP_CLOSE) 2214 mask |= POLLHUP; 2215 /* connection hasn't started yet? */ 2216 if (sk->sk_state == TCP_SYN_SENT) 2217 return mask; 2218 } 2219 2220 /* No write status requested, avoid expensive OUT tests. */ 2221 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) 2222 return mask; 2223 2224 writable = unix_writable(sk); 2225 other = unix_peer_get(sk); 2226 if (other) { 2227 if (unix_peer(other) != sk) { 2228 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2229 if (unix_recvq_full(other)) 2230 writable = 0; 2231 } 2232 sock_put(other); 2233 } 2234 2235 if (writable) 2236 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2237 else 2238 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2239 2240 return mask; 2241 } 2242 2243 #ifdef CONFIG_PROC_FS 2244 2245 #define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) 2246 2247 #define get_bucket(x) ((x) >> BUCKET_SPACE) 2248 #define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1)) 2249 #define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) 2250 2251 static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) 2252 { 2253 unsigned long offset = get_offset(*pos); 2254 unsigned long bucket = get_bucket(*pos); 2255 struct sock *sk; 2256 unsigned long count = 0; 2257 2258 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) { 2259 if (sock_net(sk) != seq_file_net(seq)) 2260 continue; 2261 if (++count == offset) 2262 break; 2263 } 2264 2265 return sk; 2266 } 2267 2268 static struct sock *unix_next_socket(struct seq_file *seq, 2269 struct sock *sk, 2270 loff_t *pos) 2271 { 2272 unsigned long bucket; 2273 2274 while (sk > (struct sock *)SEQ_START_TOKEN) { 2275 sk = sk_next(sk); 2276 if (!sk) 2277 goto next_bucket; 2278 if (sock_net(sk) == seq_file_net(seq)) 2279 return sk; 2280 } 2281 2282 do { 2283 sk = unix_from_bucket(seq, pos); 2284 if (sk) 2285 return sk; 2286 2287 next_bucket: 2288 bucket = get_bucket(*pos) + 1; 2289 *pos = set_bucket_offset(bucket, 1); 2290 } while (bucket < ARRAY_SIZE(unix_socket_table)); 2291 2292 return NULL; 2293 } 2294 2295 static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2296 __acquires(unix_table_lock) 2297 { 2298 spin_lock(&unix_table_lock); 2299 2300 if (!*pos) 2301 return SEQ_START_TOKEN; 2302 2303 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table)) 2304 return NULL; 2305 2306 return unix_next_socket(seq, NULL, pos); 2307 } 2308 2309 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2310 { 2311 ++*pos; 2312 return unix_next_socket(seq, v, pos); 2313 } 2314 2315 static void unix_seq_stop(struct seq_file *seq, void *v) 2316 __releases(unix_table_lock) 2317 { 2318 spin_unlock(&unix_table_lock); 2319 } 2320 2321 static int unix_seq_show(struct seq_file *seq, void *v) 2322 { 2323 2324 if (v == SEQ_START_TOKEN) 2325 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2326 "Inode Path\n"); 2327 else { 2328 struct sock *s = v; 2329 struct unix_sock *u = unix_sk(s); 2330 unix_state_lock(s); 2331 2332 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2333 s, 2334 atomic_read(&s->sk_refcnt), 2335 0, 2336 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2337 s->sk_type, 2338 s->sk_socket ? 2339 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2340 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2341 sock_i_ino(s)); 2342 2343 if (u->addr) { 2344 int i, len; 2345 seq_putc(seq, ' '); 2346 2347 i = 0; 2348 len = u->addr->len - sizeof(short); 2349 if (!UNIX_ABSTRACT(s)) 2350 len--; 2351 else { 2352 seq_putc(seq, '@'); 2353 i++; 2354 } 2355 for ( ; i < len; i++) 2356 seq_putc(seq, u->addr->name->sun_path[i]); 2357 } 2358 unix_state_unlock(s); 2359 seq_putc(seq, '\n'); 2360 } 2361 2362 return 0; 2363 } 2364 2365 static const struct seq_operations unix_seq_ops = { 2366 .start = unix_seq_start, 2367 .next = unix_seq_next, 2368 .stop = unix_seq_stop, 2369 .show = unix_seq_show, 2370 }; 2371 2372 static int unix_seq_open(struct inode *inode, struct file *file) 2373 { 2374 return seq_open_net(inode, file, &unix_seq_ops, 2375 sizeof(struct seq_net_private)); 2376 } 2377 2378 static const struct file_operations unix_seq_fops = { 2379 .owner = THIS_MODULE, 2380 .open = unix_seq_open, 2381 .read = seq_read, 2382 .llseek = seq_lseek, 2383 .release = seq_release_net, 2384 }; 2385 2386 #endif 2387 2388 static const struct net_proto_family unix_family_ops = { 2389 .family = PF_UNIX, 2390 .create = unix_create, 2391 .owner = THIS_MODULE, 2392 }; 2393 2394 2395 static int __net_init unix_net_init(struct net *net) 2396 { 2397 int error = -ENOMEM; 2398 2399 net->unx.sysctl_max_dgram_qlen = 10; 2400 if (unix_sysctl_register(net)) 2401 goto out; 2402 2403 #ifdef CONFIG_PROC_FS 2404 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) { 2405 unix_sysctl_unregister(net); 2406 goto out; 2407 } 2408 #endif 2409 error = 0; 2410 out: 2411 return error; 2412 } 2413 2414 static void __net_exit unix_net_exit(struct net *net) 2415 { 2416 unix_sysctl_unregister(net); 2417 remove_proc_entry("unix", net->proc_net); 2418 } 2419 2420 static struct pernet_operations unix_net_ops = { 2421 .init = unix_net_init, 2422 .exit = unix_net_exit, 2423 }; 2424 2425 static int __init af_unix_init(void) 2426 { 2427 int rc = -1; 2428 2429 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2430 2431 rc = proto_register(&unix_proto, 1); 2432 if (rc != 0) { 2433 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2434 __func__); 2435 goto out; 2436 } 2437 2438 sock_register(&unix_family_ops); 2439 register_pernet_subsys(&unix_net_ops); 2440 out: 2441 return rc; 2442 } 2443 2444 static void __exit af_unix_exit(void) 2445 { 2446 sock_unregister(PF_UNIX); 2447 proto_unregister(&unix_proto); 2448 unregister_pernet_subsys(&unix_net_ops); 2449 } 2450 2451 /* Earlier than device_initcall() so that other drivers invoking 2452 request_module() don't end up in a loop when modprobe tries 2453 to use a UNIX socket. But later than subsys_initcall() because 2454 we depend on stuff initialised there */ 2455 fs_initcall(af_unix_init); 2456 module_exit(af_unix_exit); 2457 2458 MODULE_LICENSE("GPL"); 2459 MODULE_ALIAS_NETPROTO(PF_UNIX); 2460