af_unix.c revision d4beaa66add8aebf83ab16d2fde4e4de8dac36df
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 118struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE]; 119EXPORT_SYMBOL_GPL(unix_socket_table); 120DEFINE_SPINLOCK(unix_table_lock); 121EXPORT_SYMBOL_GPL(unix_table_lock); 122static atomic_long_t unix_nr_socks; 123 124 125static struct hlist_head *unix_sockets_unbound(void *addr) 126{ 127 unsigned long hash = (unsigned long)addr; 128 129 hash ^= hash >> 16; 130 hash ^= hash >> 8; 131 hash %= UNIX_HASH_SIZE; 132 return &unix_socket_table[UNIX_HASH_SIZE + hash]; 133} 134 135#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE) 136 137#ifdef CONFIG_SECURITY_NETWORK 138static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 139{ 140 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 141} 142 143static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 144{ 145 scm->secid = *UNIXSID(skb); 146} 147#else 148static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 149{ } 150 151static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 152{ } 153#endif /* CONFIG_SECURITY_NETWORK */ 154 155/* 156 * SMP locking strategy: 157 * hash table is protected with spinlock unix_table_lock 158 * each socket state is protected by separate spin lock. 159 */ 160 161static inline unsigned int unix_hash_fold(__wsum n) 162{ 163 unsigned int hash = (__force unsigned int)n; 164 165 hash ^= hash>>16; 166 hash ^= hash>>8; 167 return hash&(UNIX_HASH_SIZE-1); 168} 169 170#define unix_peer(sk) (unix_sk(sk)->peer) 171 172static inline int unix_our_peer(struct sock *sk, struct sock *osk) 173{ 174 return unix_peer(osk) == sk; 175} 176 177static inline int unix_may_send(struct sock *sk, struct sock *osk) 178{ 179 return unix_peer(osk) == NULL || unix_our_peer(sk, osk); 180} 181 182static inline int unix_recvq_full(struct sock const *sk) 183{ 184 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; 185} 186 187struct sock *unix_peer_get(struct sock *s) 188{ 189 struct sock *peer; 190 191 unix_state_lock(s); 192 peer = unix_peer(s); 193 if (peer) 194 sock_hold(peer); 195 unix_state_unlock(s); 196 return peer; 197} 198EXPORT_SYMBOL_GPL(unix_peer_get); 199 200static inline void unix_release_addr(struct unix_address *addr) 201{ 202 if (atomic_dec_and_test(&addr->refcnt)) 203 kfree(addr); 204} 205 206/* 207 * Check unix socket name: 208 * - should be not zero length. 209 * - if started by not zero, should be NULL terminated (FS object) 210 * - if started by zero, it is abstract name. 211 */ 212 213static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp) 214{ 215 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 216 return -EINVAL; 217 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 218 return -EINVAL; 219 if (sunaddr->sun_path[0]) { 220 /* 221 * This may look like an off by one error but it is a bit more 222 * subtle. 108 is the longest valid AF_UNIX path for a binding. 223 * sun_path[108] doesn't as such exist. However in kernel space 224 * we are guaranteed that it is a valid memory location in our 225 * kernel address buffer. 226 */ 227 ((char *)sunaddr)[len] = 0; 228 len = strlen(sunaddr->sun_path)+1+sizeof(short); 229 return len; 230 } 231 232 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0)); 233 return len; 234} 235 236static void __unix_remove_socket(struct sock *sk) 237{ 238 sk_del_node_init(sk); 239} 240 241static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 242{ 243 WARN_ON(!sk_unhashed(sk)); 244 sk_add_node(sk, list); 245} 246 247static inline void unix_remove_socket(struct sock *sk) 248{ 249 spin_lock(&unix_table_lock); 250 __unix_remove_socket(sk); 251 spin_unlock(&unix_table_lock); 252} 253 254static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 255{ 256 spin_lock(&unix_table_lock); 257 __unix_insert_socket(list, sk); 258 spin_unlock(&unix_table_lock); 259} 260 261static struct sock *__unix_find_socket_byname(struct net *net, 262 struct sockaddr_un *sunname, 263 int len, int type, unsigned int hash) 264{ 265 struct sock *s; 266 struct hlist_node *node; 267 268 sk_for_each(s, node, &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; 279found: 280 return s; 281} 282 283static 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 298static struct sock *unix_find_socket_byinode(struct inode *i) 299{ 300 struct sock *s; 301 struct hlist_node *node; 302 303 spin_lock(&unix_table_lock); 304 sk_for_each(s, node, 305 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { 306 struct dentry *dentry = unix_sk(s)->path.dentry; 307 308 if (dentry && dentry->d_inode == i) { 309 sock_hold(s); 310 goto found; 311 } 312 } 313 s = NULL; 314found: 315 spin_unlock(&unix_table_lock); 316 return s; 317} 318 319static inline int unix_writable(struct sock *sk) 320{ 321 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; 322} 323 324static void unix_write_space(struct sock *sk) 325{ 326 struct socket_wq *wq; 327 328 rcu_read_lock(); 329 if (unix_writable(sk)) { 330 wq = rcu_dereference(sk->sk_wq); 331 if (wq_has_sleeper(wq)) 332 wake_up_interruptible_sync_poll(&wq->wait, 333 POLLOUT | POLLWRNORM | POLLWRBAND); 334 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); 335 } 336 rcu_read_unlock(); 337} 338 339/* When dgram socket disconnects (or changes its peer), we clear its receive 340 * queue of packets arrived from previous peer. First, it allows to do 341 * flow control based only on wmem_alloc; second, sk connected to peer 342 * may receive messages only from that peer. */ 343static void unix_dgram_disconnected(struct sock *sk, struct sock *other) 344{ 345 if (!skb_queue_empty(&sk->sk_receive_queue)) { 346 skb_queue_purge(&sk->sk_receive_queue); 347 wake_up_interruptible_all(&unix_sk(sk)->peer_wait); 348 349 /* If one link of bidirectional dgram pipe is disconnected, 350 * we signal error. Messages are lost. Do not make this, 351 * when peer was not connected to us. 352 */ 353 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { 354 other->sk_err = ECONNRESET; 355 other->sk_error_report(other); 356 } 357 } 358} 359 360static void unix_sock_destructor(struct sock *sk) 361{ 362 struct unix_sock *u = unix_sk(sk); 363 364 skb_queue_purge(&sk->sk_receive_queue); 365 366 WARN_ON(atomic_read(&sk->sk_wmem_alloc)); 367 WARN_ON(!sk_unhashed(sk)); 368 WARN_ON(sk->sk_socket); 369 if (!sock_flag(sk, SOCK_DEAD)) { 370 printk(KERN_INFO "Attempt to release alive unix socket: %p\n", sk); 371 return; 372 } 373 374 if (u->addr) 375 unix_release_addr(u->addr); 376 377 atomic_long_dec(&unix_nr_socks); 378 local_bh_disable(); 379 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 380 local_bh_enable(); 381#ifdef UNIX_REFCNT_DEBUG 382 printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk, 383 atomic_long_read(&unix_nr_socks)); 384#endif 385} 386 387static int unix_release_sock(struct sock *sk, int embrion) 388{ 389 struct unix_sock *u = unix_sk(sk); 390 struct path path; 391 struct sock *skpair; 392 struct sk_buff *skb; 393 int state; 394 395 unix_remove_socket(sk); 396 397 /* Clear state */ 398 unix_state_lock(sk); 399 sock_orphan(sk); 400 sk->sk_shutdown = SHUTDOWN_MASK; 401 path = u->path; 402 u->path.dentry = NULL; 403 u->path.mnt = NULL; 404 state = sk->sk_state; 405 sk->sk_state = TCP_CLOSE; 406 unix_state_unlock(sk); 407 408 wake_up_interruptible_all(&u->peer_wait); 409 410 skpair = unix_peer(sk); 411 412 if (skpair != NULL) { 413 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { 414 unix_state_lock(skpair); 415 /* No more writes */ 416 skpair->sk_shutdown = SHUTDOWN_MASK; 417 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) 418 skpair->sk_err = ECONNRESET; 419 unix_state_unlock(skpair); 420 skpair->sk_state_change(skpair); 421 sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP); 422 } 423 sock_put(skpair); /* It may now die */ 424 unix_peer(sk) = NULL; 425 } 426 427 /* Try to flush out this socket. Throw out buffers at least */ 428 429 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { 430 if (state == TCP_LISTEN) 431 unix_release_sock(skb->sk, 1); 432 /* passed fds are erased in the kfree_skb hook */ 433 kfree_skb(skb); 434 } 435 436 if (path.dentry) 437 path_put(&path); 438 439 sock_put(sk); 440 441 /* ---- Socket is dead now and most probably destroyed ---- */ 442 443 /* 444 * Fixme: BSD difference: In BSD all sockets connected to us get 445 * ECONNRESET and we die on the spot. In Linux we behave 446 * like files and pipes do and wait for the last 447 * dereference. 448 * 449 * Can't we simply set sock->err? 450 * 451 * What the above comment does talk about? --ANK(980817) 452 */ 453 454 if (unix_tot_inflight) 455 unix_gc(); /* Garbage collect fds */ 456 457 return 0; 458} 459 460static void init_peercred(struct sock *sk) 461{ 462 put_pid(sk->sk_peer_pid); 463 if (sk->sk_peer_cred) 464 put_cred(sk->sk_peer_cred); 465 sk->sk_peer_pid = get_pid(task_tgid(current)); 466 sk->sk_peer_cred = get_current_cred(); 467} 468 469static void copy_peercred(struct sock *sk, struct sock *peersk) 470{ 471 put_pid(sk->sk_peer_pid); 472 if (sk->sk_peer_cred) 473 put_cred(sk->sk_peer_cred); 474 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); 475 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); 476} 477 478static int unix_listen(struct socket *sock, int backlog) 479{ 480 int err; 481 struct sock *sk = sock->sk; 482 struct unix_sock *u = unix_sk(sk); 483 struct pid *old_pid = NULL; 484 485 err = -EOPNOTSUPP; 486 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 487 goto out; /* Only stream/seqpacket sockets accept */ 488 err = -EINVAL; 489 if (!u->addr) 490 goto out; /* No listens on an unbound socket */ 491 unix_state_lock(sk); 492 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 493 goto out_unlock; 494 if (backlog > sk->sk_max_ack_backlog) 495 wake_up_interruptible_all(&u->peer_wait); 496 sk->sk_max_ack_backlog = backlog; 497 sk->sk_state = TCP_LISTEN; 498 /* set credentials so connect can copy them */ 499 init_peercred(sk); 500 err = 0; 501 502out_unlock: 503 unix_state_unlock(sk); 504 put_pid(old_pid); 505out: 506 return err; 507} 508 509static int unix_release(struct socket *); 510static int unix_bind(struct socket *, struct sockaddr *, int); 511static int unix_stream_connect(struct socket *, struct sockaddr *, 512 int addr_len, int flags); 513static int unix_socketpair(struct socket *, struct socket *); 514static int unix_accept(struct socket *, struct socket *, int); 515static int unix_getname(struct socket *, struct sockaddr *, int *, int); 516static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 517static unsigned int unix_dgram_poll(struct file *, struct socket *, 518 poll_table *); 519static int unix_ioctl(struct socket *, unsigned int, unsigned long); 520static int unix_shutdown(struct socket *, int); 521static int unix_stream_sendmsg(struct kiocb *, struct socket *, 522 struct msghdr *, size_t); 523static int unix_stream_recvmsg(struct kiocb *, struct socket *, 524 struct msghdr *, size_t, int); 525static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 526 struct msghdr *, size_t); 527static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 528 struct msghdr *, size_t, int); 529static int unix_dgram_connect(struct socket *, struct sockaddr *, 530 int, int); 531static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 532 struct msghdr *, size_t); 533static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *, 534 struct msghdr *, size_t, int); 535 536static void unix_set_peek_off(struct sock *sk, int val) 537{ 538 struct unix_sock *u = unix_sk(sk); 539 540 mutex_lock(&u->readlock); 541 sk->sk_peek_off = val; 542 mutex_unlock(&u->readlock); 543} 544 545 546static const struct proto_ops unix_stream_ops = { 547 .family = PF_UNIX, 548 .owner = THIS_MODULE, 549 .release = unix_release, 550 .bind = unix_bind, 551 .connect = unix_stream_connect, 552 .socketpair = unix_socketpair, 553 .accept = unix_accept, 554 .getname = unix_getname, 555 .poll = unix_poll, 556 .ioctl = unix_ioctl, 557 .listen = unix_listen, 558 .shutdown = unix_shutdown, 559 .setsockopt = sock_no_setsockopt, 560 .getsockopt = sock_no_getsockopt, 561 .sendmsg = unix_stream_sendmsg, 562 .recvmsg = unix_stream_recvmsg, 563 .mmap = sock_no_mmap, 564 .sendpage = sock_no_sendpage, 565 .set_peek_off = unix_set_peek_off, 566}; 567 568static const struct proto_ops unix_dgram_ops = { 569 .family = PF_UNIX, 570 .owner = THIS_MODULE, 571 .release = unix_release, 572 .bind = unix_bind, 573 .connect = unix_dgram_connect, 574 .socketpair = unix_socketpair, 575 .accept = sock_no_accept, 576 .getname = unix_getname, 577 .poll = unix_dgram_poll, 578 .ioctl = unix_ioctl, 579 .listen = sock_no_listen, 580 .shutdown = unix_shutdown, 581 .setsockopt = sock_no_setsockopt, 582 .getsockopt = sock_no_getsockopt, 583 .sendmsg = unix_dgram_sendmsg, 584 .recvmsg = unix_dgram_recvmsg, 585 .mmap = sock_no_mmap, 586 .sendpage = sock_no_sendpage, 587 .set_peek_off = unix_set_peek_off, 588}; 589 590static const struct proto_ops unix_seqpacket_ops = { 591 .family = PF_UNIX, 592 .owner = THIS_MODULE, 593 .release = unix_release, 594 .bind = unix_bind, 595 .connect = unix_stream_connect, 596 .socketpair = unix_socketpair, 597 .accept = unix_accept, 598 .getname = unix_getname, 599 .poll = unix_dgram_poll, 600 .ioctl = unix_ioctl, 601 .listen = unix_listen, 602 .shutdown = unix_shutdown, 603 .setsockopt = sock_no_setsockopt, 604 .getsockopt = sock_no_getsockopt, 605 .sendmsg = unix_seqpacket_sendmsg, 606 .recvmsg = unix_seqpacket_recvmsg, 607 .mmap = sock_no_mmap, 608 .sendpage = sock_no_sendpage, 609 .set_peek_off = unix_set_peek_off, 610}; 611 612static struct proto unix_proto = { 613 .name = "UNIX", 614 .owner = THIS_MODULE, 615 .obj_size = sizeof(struct unix_sock), 616}; 617 618/* 619 * AF_UNIX sockets do not interact with hardware, hence they 620 * dont trigger interrupts - so it's safe for them to have 621 * bh-unsafe locking for their sk_receive_queue.lock. Split off 622 * this special lock-class by reinitializing the spinlock key: 623 */ 624static struct lock_class_key af_unix_sk_receive_queue_lock_key; 625 626static struct sock *unix_create1(struct net *net, struct socket *sock) 627{ 628 struct sock *sk = NULL; 629 struct unix_sock *u; 630 631 atomic_long_inc(&unix_nr_socks); 632 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) 633 goto out; 634 635 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto); 636 if (!sk) 637 goto out; 638 639 sock_init_data(sock, sk); 640 lockdep_set_class(&sk->sk_receive_queue.lock, 641 &af_unix_sk_receive_queue_lock_key); 642 643 sk->sk_write_space = unix_write_space; 644 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; 645 sk->sk_destruct = unix_sock_destructor; 646 u = unix_sk(sk); 647 u->path.dentry = NULL; 648 u->path.mnt = NULL; 649 spin_lock_init(&u->lock); 650 atomic_long_set(&u->inflight, 0); 651 INIT_LIST_HEAD(&u->link); 652 mutex_init(&u->readlock); /* single task reading lock */ 653 init_waitqueue_head(&u->peer_wait); 654 unix_insert_socket(unix_sockets_unbound(sk), sk); 655out: 656 if (sk == NULL) 657 atomic_long_dec(&unix_nr_socks); 658 else { 659 local_bh_disable(); 660 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 661 local_bh_enable(); 662 } 663 return sk; 664} 665 666static int unix_create(struct net *net, struct socket *sock, int protocol, 667 int kern) 668{ 669 if (protocol && protocol != PF_UNIX) 670 return -EPROTONOSUPPORT; 671 672 sock->state = SS_UNCONNECTED; 673 674 switch (sock->type) { 675 case SOCK_STREAM: 676 sock->ops = &unix_stream_ops; 677 break; 678 /* 679 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 680 * nothing uses it. 681 */ 682 case SOCK_RAW: 683 sock->type = SOCK_DGRAM; 684 case SOCK_DGRAM: 685 sock->ops = &unix_dgram_ops; 686 break; 687 case SOCK_SEQPACKET: 688 sock->ops = &unix_seqpacket_ops; 689 break; 690 default: 691 return -ESOCKTNOSUPPORT; 692 } 693 694 return unix_create1(net, sock) ? 0 : -ENOMEM; 695} 696 697static int unix_release(struct socket *sock) 698{ 699 struct sock *sk = sock->sk; 700 701 if (!sk) 702 return 0; 703 704 sock->sk = NULL; 705 706 return unix_release_sock(sk, 0); 707} 708 709static int unix_autobind(struct socket *sock) 710{ 711 struct sock *sk = sock->sk; 712 struct net *net = sock_net(sk); 713 struct unix_sock *u = unix_sk(sk); 714 static u32 ordernum = 1; 715 struct unix_address *addr; 716 int err; 717 unsigned int retries = 0; 718 719 mutex_lock(&u->readlock); 720 721 err = 0; 722 if (u->addr) 723 goto out; 724 725 err = -ENOMEM; 726 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 727 if (!addr) 728 goto out; 729 730 addr->name->sun_family = AF_UNIX; 731 atomic_set(&addr->refcnt, 1); 732 733retry: 734 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 735 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0)); 736 737 spin_lock(&unix_table_lock); 738 ordernum = (ordernum+1)&0xFFFFF; 739 740 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type, 741 addr->hash)) { 742 spin_unlock(&unix_table_lock); 743 /* 744 * __unix_find_socket_byname() may take long time if many names 745 * are already in use. 746 */ 747 cond_resched(); 748 /* Give up if all names seems to be in use. */ 749 if (retries++ == 0xFFFFF) { 750 err = -ENOSPC; 751 kfree(addr); 752 goto out; 753 } 754 goto retry; 755 } 756 addr->hash ^= sk->sk_type; 757 758 __unix_remove_socket(sk); 759 u->addr = addr; 760 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 761 spin_unlock(&unix_table_lock); 762 err = 0; 763 764out: mutex_unlock(&u->readlock); 765 return err; 766} 767 768static struct sock *unix_find_other(struct net *net, 769 struct sockaddr_un *sunname, int len, 770 int type, unsigned int hash, int *error) 771{ 772 struct sock *u; 773 struct path path; 774 int err = 0; 775 776 if (sunname->sun_path[0]) { 777 struct inode *inode; 778 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); 779 if (err) 780 goto fail; 781 inode = path.dentry->d_inode; 782 err = inode_permission(inode, MAY_WRITE); 783 if (err) 784 goto put_fail; 785 786 err = -ECONNREFUSED; 787 if (!S_ISSOCK(inode->i_mode)) 788 goto put_fail; 789 u = unix_find_socket_byinode(inode); 790 if (!u) 791 goto put_fail; 792 793 if (u->sk_type == type) 794 touch_atime(&path); 795 796 path_put(&path); 797 798 err = -EPROTOTYPE; 799 if (u->sk_type != type) { 800 sock_put(u); 801 goto fail; 802 } 803 } else { 804 err = -ECONNREFUSED; 805 u = unix_find_socket_byname(net, sunname, len, type, hash); 806 if (u) { 807 struct dentry *dentry; 808 dentry = unix_sk(u)->path.dentry; 809 if (dentry) 810 touch_atime(&unix_sk(u)->path); 811 } else 812 goto fail; 813 } 814 return u; 815 816put_fail: 817 path_put(&path); 818fail: 819 *error = err; 820 return NULL; 821} 822 823static int unix_mknod(const char *sun_path, umode_t mode, struct path *res) 824{ 825 struct dentry *dentry; 826 struct path path; 827 int err = 0; 828 /* 829 * Get the parent directory, calculate the hash for last 830 * component. 831 */ 832 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0); 833 err = PTR_ERR(dentry); 834 if (IS_ERR(dentry)) 835 return err; 836 837 /* 838 * All right, let's create it. 839 */ 840 err = security_path_mknod(&path, dentry, mode, 0); 841 if (!err) { 842 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0); 843 if (!err) { 844 res->mnt = mntget(path.mnt); 845 res->dentry = dget(dentry); 846 } 847 } 848 done_path_create(&path, dentry); 849 return err; 850} 851 852static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 853{ 854 struct sock *sk = sock->sk; 855 struct net *net = sock_net(sk); 856 struct unix_sock *u = unix_sk(sk); 857 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 858 char *sun_path = sunaddr->sun_path; 859 int err; 860 unsigned int hash; 861 struct unix_address *addr; 862 struct hlist_head *list; 863 864 err = -EINVAL; 865 if (sunaddr->sun_family != AF_UNIX) 866 goto out; 867 868 if (addr_len == sizeof(short)) { 869 err = unix_autobind(sock); 870 goto out; 871 } 872 873 err = unix_mkname(sunaddr, addr_len, &hash); 874 if (err < 0) 875 goto out; 876 addr_len = err; 877 878 mutex_lock(&u->readlock); 879 880 err = -EINVAL; 881 if (u->addr) 882 goto out_up; 883 884 err = -ENOMEM; 885 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 886 if (!addr) 887 goto out_up; 888 889 memcpy(addr->name, sunaddr, addr_len); 890 addr->len = addr_len; 891 addr->hash = hash ^ sk->sk_type; 892 atomic_set(&addr->refcnt, 1); 893 894 if (sun_path[0]) { 895 struct path path; 896 umode_t mode = S_IFSOCK | 897 (SOCK_INODE(sock)->i_mode & ~current_umask()); 898 err = unix_mknod(sun_path, mode, &path); 899 if (err) { 900 if (err == -EEXIST) 901 err = -EADDRINUSE; 902 unix_release_addr(addr); 903 goto out_up; 904 } 905 addr->hash = UNIX_HASH_SIZE; 906 hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1); 907 spin_lock(&unix_table_lock); 908 u->path = path; 909 list = &unix_socket_table[hash]; 910 } else { 911 spin_lock(&unix_table_lock); 912 err = -EADDRINUSE; 913 if (__unix_find_socket_byname(net, sunaddr, addr_len, 914 sk->sk_type, hash)) { 915 unix_release_addr(addr); 916 goto out_unlock; 917 } 918 919 list = &unix_socket_table[addr->hash]; 920 } 921 922 err = 0; 923 __unix_remove_socket(sk); 924 u->addr = addr; 925 __unix_insert_socket(list, sk); 926 927out_unlock: 928 spin_unlock(&unix_table_lock); 929out_up: 930 mutex_unlock(&u->readlock); 931out: 932 return err; 933} 934 935static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) 936{ 937 if (unlikely(sk1 == sk2) || !sk2) { 938 unix_state_lock(sk1); 939 return; 940 } 941 if (sk1 < sk2) { 942 unix_state_lock(sk1); 943 unix_state_lock_nested(sk2); 944 } else { 945 unix_state_lock(sk2); 946 unix_state_lock_nested(sk1); 947 } 948} 949 950static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) 951{ 952 if (unlikely(sk1 == sk2) || !sk2) { 953 unix_state_unlock(sk1); 954 return; 955 } 956 unix_state_unlock(sk1); 957 unix_state_unlock(sk2); 958} 959 960static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 961 int alen, int flags) 962{ 963 struct sock *sk = sock->sk; 964 struct net *net = sock_net(sk); 965 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; 966 struct sock *other; 967 unsigned int hash; 968 int err; 969 970 if (addr->sa_family != AF_UNSPEC) { 971 err = unix_mkname(sunaddr, alen, &hash); 972 if (err < 0) 973 goto out; 974 alen = err; 975 976 if (test_bit(SOCK_PASSCRED, &sock->flags) && 977 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 978 goto out; 979 980restart: 981 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); 982 if (!other) 983 goto out; 984 985 unix_state_double_lock(sk, other); 986 987 /* Apparently VFS overslept socket death. Retry. */ 988 if (sock_flag(other, SOCK_DEAD)) { 989 unix_state_double_unlock(sk, other); 990 sock_put(other); 991 goto restart; 992 } 993 994 err = -EPERM; 995 if (!unix_may_send(sk, other)) 996 goto out_unlock; 997 998 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 999 if (err) 1000 goto out_unlock; 1001 1002 } else { 1003 /* 1004 * 1003.1g breaking connected state with AF_UNSPEC 1005 */ 1006 other = NULL; 1007 unix_state_double_lock(sk, other); 1008 } 1009 1010 /* 1011 * If it was connected, reconnect. 1012 */ 1013 if (unix_peer(sk)) { 1014 struct sock *old_peer = unix_peer(sk); 1015 unix_peer(sk) = other; 1016 unix_state_double_unlock(sk, other); 1017 1018 if (other != old_peer) 1019 unix_dgram_disconnected(sk, old_peer); 1020 sock_put(old_peer); 1021 } else { 1022 unix_peer(sk) = other; 1023 unix_state_double_unlock(sk, other); 1024 } 1025 return 0; 1026 1027out_unlock: 1028 unix_state_double_unlock(sk, other); 1029 sock_put(other); 1030out: 1031 return err; 1032} 1033 1034static long unix_wait_for_peer(struct sock *other, long timeo) 1035{ 1036 struct unix_sock *u = unix_sk(other); 1037 int sched; 1038 DEFINE_WAIT(wait); 1039 1040 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 1041 1042 sched = !sock_flag(other, SOCK_DEAD) && 1043 !(other->sk_shutdown & RCV_SHUTDOWN) && 1044 unix_recvq_full(other); 1045 1046 unix_state_unlock(other); 1047 1048 if (sched) 1049 timeo = schedule_timeout(timeo); 1050 1051 finish_wait(&u->peer_wait, &wait); 1052 return timeo; 1053} 1054 1055static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 1056 int addr_len, int flags) 1057{ 1058 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 1059 struct sock *sk = sock->sk; 1060 struct net *net = sock_net(sk); 1061 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 1062 struct sock *newsk = NULL; 1063 struct sock *other = NULL; 1064 struct sk_buff *skb = NULL; 1065 unsigned int hash; 1066 int st; 1067 int err; 1068 long timeo; 1069 1070 err = unix_mkname(sunaddr, addr_len, &hash); 1071 if (err < 0) 1072 goto out; 1073 addr_len = err; 1074 1075 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && 1076 (err = unix_autobind(sock)) != 0) 1077 goto out; 1078 1079 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 1080 1081 /* First of all allocate resources. 1082 If we will make it after state is locked, 1083 we will have to recheck all again in any case. 1084 */ 1085 1086 err = -ENOMEM; 1087 1088 /* create new sock for complete connection */ 1089 newsk = unix_create1(sock_net(sk), NULL); 1090 if (newsk == NULL) 1091 goto out; 1092 1093 /* Allocate skb for sending to listening sock */ 1094 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 1095 if (skb == NULL) 1096 goto out; 1097 1098restart: 1099 /* Find listening sock. */ 1100 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); 1101 if (!other) 1102 goto out; 1103 1104 /* Latch state of peer */ 1105 unix_state_lock(other); 1106 1107 /* Apparently VFS overslept socket death. Retry. */ 1108 if (sock_flag(other, SOCK_DEAD)) { 1109 unix_state_unlock(other); 1110 sock_put(other); 1111 goto restart; 1112 } 1113 1114 err = -ECONNREFUSED; 1115 if (other->sk_state != TCP_LISTEN) 1116 goto out_unlock; 1117 if (other->sk_shutdown & RCV_SHUTDOWN) 1118 goto out_unlock; 1119 1120 if (unix_recvq_full(other)) { 1121 err = -EAGAIN; 1122 if (!timeo) 1123 goto out_unlock; 1124 1125 timeo = unix_wait_for_peer(other, timeo); 1126 1127 err = sock_intr_errno(timeo); 1128 if (signal_pending(current)) 1129 goto out; 1130 sock_put(other); 1131 goto restart; 1132 } 1133 1134 /* Latch our state. 1135 1136 It is tricky place. We need to grab our state lock and cannot 1137 drop lock on peer. It is dangerous because deadlock is 1138 possible. Connect to self case and simultaneous 1139 attempt to connect are eliminated by checking socket 1140 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1141 check this before attempt to grab lock. 1142 1143 Well, and we have to recheck the state after socket locked. 1144 */ 1145 st = sk->sk_state; 1146 1147 switch (st) { 1148 case TCP_CLOSE: 1149 /* This is ok... continue with connect */ 1150 break; 1151 case TCP_ESTABLISHED: 1152 /* Socket is already connected */ 1153 err = -EISCONN; 1154 goto out_unlock; 1155 default: 1156 err = -EINVAL; 1157 goto out_unlock; 1158 } 1159 1160 unix_state_lock_nested(sk); 1161 1162 if (sk->sk_state != st) { 1163 unix_state_unlock(sk); 1164 unix_state_unlock(other); 1165 sock_put(other); 1166 goto restart; 1167 } 1168 1169 err = security_unix_stream_connect(sk, other, newsk); 1170 if (err) { 1171 unix_state_unlock(sk); 1172 goto out_unlock; 1173 } 1174 1175 /* The way is open! Fastly set all the necessary fields... */ 1176 1177 sock_hold(sk); 1178 unix_peer(newsk) = sk; 1179 newsk->sk_state = TCP_ESTABLISHED; 1180 newsk->sk_type = sk->sk_type; 1181 init_peercred(newsk); 1182 newu = unix_sk(newsk); 1183 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); 1184 otheru = unix_sk(other); 1185 1186 /* copy address information from listening to new sock*/ 1187 if (otheru->addr) { 1188 atomic_inc(&otheru->addr->refcnt); 1189 newu->addr = otheru->addr; 1190 } 1191 if (otheru->path.dentry) { 1192 path_get(&otheru->path); 1193 newu->path = otheru->path; 1194 } 1195 1196 /* Set credentials */ 1197 copy_peercred(sk, other); 1198 1199 sock->state = SS_CONNECTED; 1200 sk->sk_state = TCP_ESTABLISHED; 1201 sock_hold(newsk); 1202 1203 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1204 unix_peer(sk) = newsk; 1205 1206 unix_state_unlock(sk); 1207 1208 /* take ten and and send info to listening sock */ 1209 spin_lock(&other->sk_receive_queue.lock); 1210 __skb_queue_tail(&other->sk_receive_queue, skb); 1211 spin_unlock(&other->sk_receive_queue.lock); 1212 unix_state_unlock(other); 1213 other->sk_data_ready(other, 0); 1214 sock_put(other); 1215 return 0; 1216 1217out_unlock: 1218 if (other) 1219 unix_state_unlock(other); 1220 1221out: 1222 kfree_skb(skb); 1223 if (newsk) 1224 unix_release_sock(newsk, 0); 1225 if (other) 1226 sock_put(other); 1227 return err; 1228} 1229 1230static int unix_socketpair(struct socket *socka, struct socket *sockb) 1231{ 1232 struct sock *ska = socka->sk, *skb = sockb->sk; 1233 1234 /* Join our sockets back to back */ 1235 sock_hold(ska); 1236 sock_hold(skb); 1237 unix_peer(ska) = skb; 1238 unix_peer(skb) = ska; 1239 init_peercred(ska); 1240 init_peercred(skb); 1241 1242 if (ska->sk_type != SOCK_DGRAM) { 1243 ska->sk_state = TCP_ESTABLISHED; 1244 skb->sk_state = TCP_ESTABLISHED; 1245 socka->state = SS_CONNECTED; 1246 sockb->state = SS_CONNECTED; 1247 } 1248 return 0; 1249} 1250 1251static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1252{ 1253 struct sock *sk = sock->sk; 1254 struct sock *tsk; 1255 struct sk_buff *skb; 1256 int err; 1257 1258 err = -EOPNOTSUPP; 1259 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 1260 goto out; 1261 1262 err = -EINVAL; 1263 if (sk->sk_state != TCP_LISTEN) 1264 goto out; 1265 1266 /* If socket state is TCP_LISTEN it cannot change (for now...), 1267 * so that no locks are necessary. 1268 */ 1269 1270 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1271 if (!skb) { 1272 /* This means receive shutdown. */ 1273 if (err == 0) 1274 err = -EINVAL; 1275 goto out; 1276 } 1277 1278 tsk = skb->sk; 1279 skb_free_datagram(sk, skb); 1280 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1281 1282 /* attach accepted sock to socket */ 1283 unix_state_lock(tsk); 1284 newsock->state = SS_CONNECTED; 1285 sock_graft(tsk, newsock); 1286 unix_state_unlock(tsk); 1287 return 0; 1288 1289out: 1290 return err; 1291} 1292 1293 1294static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1295{ 1296 struct sock *sk = sock->sk; 1297 struct unix_sock *u; 1298 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); 1299 int err = 0; 1300 1301 if (peer) { 1302 sk = unix_peer_get(sk); 1303 1304 err = -ENOTCONN; 1305 if (!sk) 1306 goto out; 1307 err = 0; 1308 } else { 1309 sock_hold(sk); 1310 } 1311 1312 u = unix_sk(sk); 1313 unix_state_lock(sk); 1314 if (!u->addr) { 1315 sunaddr->sun_family = AF_UNIX; 1316 sunaddr->sun_path[0] = 0; 1317 *uaddr_len = sizeof(short); 1318 } else { 1319 struct unix_address *addr = u->addr; 1320 1321 *uaddr_len = addr->len; 1322 memcpy(sunaddr, addr->name, *uaddr_len); 1323 } 1324 unix_state_unlock(sk); 1325 sock_put(sk); 1326out: 1327 return err; 1328} 1329 1330static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1331{ 1332 int i; 1333 1334 scm->fp = UNIXCB(skb).fp; 1335 UNIXCB(skb).fp = NULL; 1336 1337 for (i = scm->fp->count-1; i >= 0; i--) 1338 unix_notinflight(scm->fp->fp[i]); 1339} 1340 1341static void unix_destruct_scm(struct sk_buff *skb) 1342{ 1343 struct scm_cookie scm; 1344 memset(&scm, 0, sizeof(scm)); 1345 scm.pid = UNIXCB(skb).pid; 1346 scm.cred = UNIXCB(skb).cred; 1347 if (UNIXCB(skb).fp) 1348 unix_detach_fds(&scm, skb); 1349 1350 /* Alas, it calls VFS */ 1351 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1352 scm_destroy(&scm); 1353 sock_wfree(skb); 1354} 1355 1356#define MAX_RECURSION_LEVEL 4 1357 1358static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1359{ 1360 int i; 1361 unsigned char max_level = 0; 1362 int unix_sock_count = 0; 1363 1364 for (i = scm->fp->count - 1; i >= 0; i--) { 1365 struct sock *sk = unix_get_socket(scm->fp->fp[i]); 1366 1367 if (sk) { 1368 unix_sock_count++; 1369 max_level = max(max_level, 1370 unix_sk(sk)->recursion_level); 1371 } 1372 } 1373 if (unlikely(max_level > MAX_RECURSION_LEVEL)) 1374 return -ETOOMANYREFS; 1375 1376 /* 1377 * Need to duplicate file references for the sake of garbage 1378 * collection. Otherwise a socket in the fps might become a 1379 * candidate for GC while the skb is not yet queued. 1380 */ 1381 UNIXCB(skb).fp = scm_fp_dup(scm->fp); 1382 if (!UNIXCB(skb).fp) 1383 return -ENOMEM; 1384 1385 if (unix_sock_count) { 1386 for (i = scm->fp->count - 1; i >= 0; i--) 1387 unix_inflight(scm->fp->fp[i]); 1388 } 1389 return max_level; 1390} 1391 1392static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) 1393{ 1394 int err = 0; 1395 1396 UNIXCB(skb).pid = get_pid(scm->pid); 1397 if (scm->cred) 1398 UNIXCB(skb).cred = get_cred(scm->cred); 1399 UNIXCB(skb).fp = NULL; 1400 if (scm->fp && send_fds) 1401 err = unix_attach_fds(scm, skb); 1402 1403 skb->destructor = unix_destruct_scm; 1404 return err; 1405} 1406 1407/* 1408 * Some apps rely on write() giving SCM_CREDENTIALS 1409 * We include credentials if source or destination socket 1410 * asserted SOCK_PASSCRED. 1411 */ 1412static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, 1413 const struct sock *other) 1414{ 1415 if (UNIXCB(skb).cred) 1416 return; 1417 if (test_bit(SOCK_PASSCRED, &sock->flags) || 1418 !other->sk_socket || 1419 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { 1420 UNIXCB(skb).pid = get_pid(task_tgid(current)); 1421 UNIXCB(skb).cred = get_current_cred(); 1422 } 1423} 1424 1425/* 1426 * Send AF_UNIX data. 1427 */ 1428 1429static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1430 struct msghdr *msg, size_t len) 1431{ 1432 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1433 struct sock *sk = sock->sk; 1434 struct net *net = sock_net(sk); 1435 struct unix_sock *u = unix_sk(sk); 1436 struct sockaddr_un *sunaddr = msg->msg_name; 1437 struct sock *other = NULL; 1438 int namelen = 0; /* fake GCC */ 1439 int err; 1440 unsigned int hash; 1441 struct sk_buff *skb; 1442 long timeo; 1443 struct scm_cookie tmp_scm; 1444 int max_level; 1445 int data_len = 0; 1446 1447 if (NULL == siocb->scm) 1448 siocb->scm = &tmp_scm; 1449 wait_for_unix_gc(); 1450 err = scm_send(sock, msg, siocb->scm, false); 1451 if (err < 0) 1452 return err; 1453 1454 err = -EOPNOTSUPP; 1455 if (msg->msg_flags&MSG_OOB) 1456 goto out; 1457 1458 if (msg->msg_namelen) { 1459 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1460 if (err < 0) 1461 goto out; 1462 namelen = err; 1463 } else { 1464 sunaddr = NULL; 1465 err = -ENOTCONN; 1466 other = unix_peer_get(sk); 1467 if (!other) 1468 goto out; 1469 } 1470 1471 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr 1472 && (err = unix_autobind(sock)) != 0) 1473 goto out; 1474 1475 err = -EMSGSIZE; 1476 if (len > sk->sk_sndbuf - 32) 1477 goto out; 1478 1479 if (len > SKB_MAX_ALLOC) 1480 data_len = min_t(size_t, 1481 len - SKB_MAX_ALLOC, 1482 MAX_SKB_FRAGS * PAGE_SIZE); 1483 1484 skb = sock_alloc_send_pskb(sk, len - data_len, data_len, 1485 msg->msg_flags & MSG_DONTWAIT, &err); 1486 if (skb == NULL) 1487 goto out; 1488 1489 err = unix_scm_to_skb(siocb->scm, skb, true); 1490 if (err < 0) 1491 goto out_free; 1492 max_level = err + 1; 1493 unix_get_secdata(siocb->scm, skb); 1494 1495 skb_put(skb, len - data_len); 1496 skb->data_len = data_len; 1497 skb->len = len; 1498 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len); 1499 if (err) 1500 goto out_free; 1501 1502 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1503 1504restart: 1505 if (!other) { 1506 err = -ECONNRESET; 1507 if (sunaddr == NULL) 1508 goto out_free; 1509 1510 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1511 hash, &err); 1512 if (other == NULL) 1513 goto out_free; 1514 } 1515 1516 if (sk_filter(other, skb) < 0) { 1517 /* Toss the packet but do not return any error to the sender */ 1518 err = len; 1519 goto out_free; 1520 } 1521 1522 unix_state_lock(other); 1523 err = -EPERM; 1524 if (!unix_may_send(sk, other)) 1525 goto out_unlock; 1526 1527 if (sock_flag(other, SOCK_DEAD)) { 1528 /* 1529 * Check with 1003.1g - what should 1530 * datagram error 1531 */ 1532 unix_state_unlock(other); 1533 sock_put(other); 1534 1535 err = 0; 1536 unix_state_lock(sk); 1537 if (unix_peer(sk) == other) { 1538 unix_peer(sk) = NULL; 1539 unix_state_unlock(sk); 1540 1541 unix_dgram_disconnected(sk, other); 1542 sock_put(other); 1543 err = -ECONNREFUSED; 1544 } else { 1545 unix_state_unlock(sk); 1546 } 1547 1548 other = NULL; 1549 if (err) 1550 goto out_free; 1551 goto restart; 1552 } 1553 1554 err = -EPIPE; 1555 if (other->sk_shutdown & RCV_SHUTDOWN) 1556 goto out_unlock; 1557 1558 if (sk->sk_type != SOCK_SEQPACKET) { 1559 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1560 if (err) 1561 goto out_unlock; 1562 } 1563 1564 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1565 if (!timeo) { 1566 err = -EAGAIN; 1567 goto out_unlock; 1568 } 1569 1570 timeo = unix_wait_for_peer(other, timeo); 1571 1572 err = sock_intr_errno(timeo); 1573 if (signal_pending(current)) 1574 goto out_free; 1575 1576 goto restart; 1577 } 1578 1579 if (sock_flag(other, SOCK_RCVTSTAMP)) 1580 __net_timestamp(skb); 1581 maybe_add_creds(skb, sock, other); 1582 skb_queue_tail(&other->sk_receive_queue, skb); 1583 if (max_level > unix_sk(other)->recursion_level) 1584 unix_sk(other)->recursion_level = max_level; 1585 unix_state_unlock(other); 1586 other->sk_data_ready(other, len); 1587 sock_put(other); 1588 scm_destroy(siocb->scm); 1589 return len; 1590 1591out_unlock: 1592 unix_state_unlock(other); 1593out_free: 1594 kfree_skb(skb); 1595out: 1596 if (other) 1597 sock_put(other); 1598 scm_destroy(siocb->scm); 1599 return err; 1600} 1601 1602 1603static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1604 struct msghdr *msg, size_t len) 1605{ 1606 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1607 struct sock *sk = sock->sk; 1608 struct sock *other = NULL; 1609 int err, size; 1610 struct sk_buff *skb; 1611 int sent = 0; 1612 struct scm_cookie tmp_scm; 1613 bool fds_sent = false; 1614 int max_level; 1615 1616 if (NULL == siocb->scm) 1617 siocb->scm = &tmp_scm; 1618 wait_for_unix_gc(); 1619 err = scm_send(sock, msg, siocb->scm, false); 1620 if (err < 0) 1621 return err; 1622 1623 err = -EOPNOTSUPP; 1624 if (msg->msg_flags&MSG_OOB) 1625 goto out_err; 1626 1627 if (msg->msg_namelen) { 1628 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1629 goto out_err; 1630 } else { 1631 err = -ENOTCONN; 1632 other = unix_peer(sk); 1633 if (!other) 1634 goto out_err; 1635 } 1636 1637 if (sk->sk_shutdown & SEND_SHUTDOWN) 1638 goto pipe_err; 1639 1640 while (sent < len) { 1641 /* 1642 * Optimisation for the fact that under 0.01% of X 1643 * messages typically need breaking up. 1644 */ 1645 1646 size = len-sent; 1647 1648 /* Keep two messages in the pipe so it schedules better */ 1649 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1650 size = (sk->sk_sndbuf >> 1) - 64; 1651 1652 if (size > SKB_MAX_ALLOC) 1653 size = SKB_MAX_ALLOC; 1654 1655 /* 1656 * Grab a buffer 1657 */ 1658 1659 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT, 1660 &err); 1661 1662 if (skb == NULL) 1663 goto out_err; 1664 1665 /* 1666 * If you pass two values to the sock_alloc_send_skb 1667 * it tries to grab the large buffer with GFP_NOFS 1668 * (which can fail easily), and if it fails grab the 1669 * fallback size buffer which is under a page and will 1670 * succeed. [Alan] 1671 */ 1672 size = min_t(int, size, skb_tailroom(skb)); 1673 1674 1675 /* Only send the fds in the first buffer */ 1676 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1677 if (err < 0) { 1678 kfree_skb(skb); 1679 goto out_err; 1680 } 1681 max_level = err + 1; 1682 fds_sent = true; 1683 1684 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size); 1685 if (err) { 1686 kfree_skb(skb); 1687 goto out_err; 1688 } 1689 1690 unix_state_lock(other); 1691 1692 if (sock_flag(other, SOCK_DEAD) || 1693 (other->sk_shutdown & RCV_SHUTDOWN)) 1694 goto pipe_err_free; 1695 1696 maybe_add_creds(skb, sock, other); 1697 skb_queue_tail(&other->sk_receive_queue, skb); 1698 if (max_level > unix_sk(other)->recursion_level) 1699 unix_sk(other)->recursion_level = max_level; 1700 unix_state_unlock(other); 1701 other->sk_data_ready(other, size); 1702 sent += size; 1703 } 1704 1705 scm_destroy(siocb->scm); 1706 siocb->scm = NULL; 1707 1708 return sent; 1709 1710pipe_err_free: 1711 unix_state_unlock(other); 1712 kfree_skb(skb); 1713pipe_err: 1714 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1715 send_sig(SIGPIPE, current, 0); 1716 err = -EPIPE; 1717out_err: 1718 scm_destroy(siocb->scm); 1719 siocb->scm = NULL; 1720 return sent ? : err; 1721} 1722 1723static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1724 struct msghdr *msg, size_t len) 1725{ 1726 int err; 1727 struct sock *sk = sock->sk; 1728 1729 err = sock_error(sk); 1730 if (err) 1731 return err; 1732 1733 if (sk->sk_state != TCP_ESTABLISHED) 1734 return -ENOTCONN; 1735 1736 if (msg->msg_namelen) 1737 msg->msg_namelen = 0; 1738 1739 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1740} 1741 1742static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1743 struct msghdr *msg, size_t size, 1744 int flags) 1745{ 1746 struct sock *sk = sock->sk; 1747 1748 if (sk->sk_state != TCP_ESTABLISHED) 1749 return -ENOTCONN; 1750 1751 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1752} 1753 1754static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1755{ 1756 struct unix_sock *u = unix_sk(sk); 1757 1758 msg->msg_namelen = 0; 1759 if (u->addr) { 1760 msg->msg_namelen = u->addr->len; 1761 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1762 } 1763} 1764 1765static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1766 struct msghdr *msg, size_t size, 1767 int flags) 1768{ 1769 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1770 struct scm_cookie tmp_scm; 1771 struct sock *sk = sock->sk; 1772 struct unix_sock *u = unix_sk(sk); 1773 int noblock = flags & MSG_DONTWAIT; 1774 struct sk_buff *skb; 1775 int err; 1776 int peeked, skip; 1777 1778 err = -EOPNOTSUPP; 1779 if (flags&MSG_OOB) 1780 goto out; 1781 1782 msg->msg_namelen = 0; 1783 1784 err = mutex_lock_interruptible(&u->readlock); 1785 if (err) { 1786 err = sock_intr_errno(sock_rcvtimeo(sk, noblock)); 1787 goto out; 1788 } 1789 1790 skip = sk_peek_offset(sk, flags); 1791 1792 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); 1793 if (!skb) { 1794 unix_state_lock(sk); 1795 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1796 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1797 (sk->sk_shutdown & RCV_SHUTDOWN)) 1798 err = 0; 1799 unix_state_unlock(sk); 1800 goto out_unlock; 1801 } 1802 1803 wake_up_interruptible_sync_poll(&u->peer_wait, 1804 POLLOUT | POLLWRNORM | POLLWRBAND); 1805 1806 if (msg->msg_name) 1807 unix_copy_addr(msg, skb->sk); 1808 1809 if (size > skb->len - skip) 1810 size = skb->len - skip; 1811 else if (size < skb->len - skip) 1812 msg->msg_flags |= MSG_TRUNC; 1813 1814 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size); 1815 if (err) 1816 goto out_free; 1817 1818 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1819 __sock_recv_timestamp(msg, sk, skb); 1820 1821 if (!siocb->scm) { 1822 siocb->scm = &tmp_scm; 1823 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1824 } 1825 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 1826 unix_set_secdata(siocb->scm, skb); 1827 1828 if (!(flags & MSG_PEEK)) { 1829 if (UNIXCB(skb).fp) 1830 unix_detach_fds(siocb->scm, skb); 1831 1832 sk_peek_offset_bwd(sk, skb->len); 1833 } else { 1834 /* It is questionable: on PEEK we could: 1835 - do not return fds - good, but too simple 8) 1836 - return fds, and do not return them on read (old strategy, 1837 apparently wrong) 1838 - clone fds (I chose it for now, it is the most universal 1839 solution) 1840 1841 POSIX 1003.1g does not actually define this clearly 1842 at all. POSIX 1003.1g doesn't define a lot of things 1843 clearly however! 1844 1845 */ 1846 1847 sk_peek_offset_fwd(sk, size); 1848 1849 if (UNIXCB(skb).fp) 1850 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1851 } 1852 err = (flags & MSG_TRUNC) ? skb->len - skip : size; 1853 1854 scm_recv(sock, msg, siocb->scm, flags); 1855 1856out_free: 1857 skb_free_datagram(sk, skb); 1858out_unlock: 1859 mutex_unlock(&u->readlock); 1860out: 1861 return err; 1862} 1863 1864/* 1865 * Sleep until data has arrive. But check for races.. 1866 */ 1867 1868static long unix_stream_data_wait(struct sock *sk, long timeo) 1869{ 1870 DEFINE_WAIT(wait); 1871 1872 unix_state_lock(sk); 1873 1874 for (;;) { 1875 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1876 1877 if (!skb_queue_empty(&sk->sk_receive_queue) || 1878 sk->sk_err || 1879 (sk->sk_shutdown & RCV_SHUTDOWN) || 1880 signal_pending(current) || 1881 !timeo) 1882 break; 1883 1884 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1885 unix_state_unlock(sk); 1886 timeo = schedule_timeout(timeo); 1887 unix_state_lock(sk); 1888 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1889 } 1890 1891 finish_wait(sk_sleep(sk), &wait); 1892 unix_state_unlock(sk); 1893 return timeo; 1894} 1895 1896 1897 1898static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1899 struct msghdr *msg, size_t size, 1900 int flags) 1901{ 1902 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1903 struct scm_cookie tmp_scm; 1904 struct sock *sk = sock->sk; 1905 struct unix_sock *u = unix_sk(sk); 1906 struct sockaddr_un *sunaddr = msg->msg_name; 1907 int copied = 0; 1908 int check_creds = 0; 1909 int target; 1910 int err = 0; 1911 long timeo; 1912 int skip; 1913 1914 err = -EINVAL; 1915 if (sk->sk_state != TCP_ESTABLISHED) 1916 goto out; 1917 1918 err = -EOPNOTSUPP; 1919 if (flags&MSG_OOB) 1920 goto out; 1921 1922 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1923 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1924 1925 msg->msg_namelen = 0; 1926 1927 /* Lock the socket to prevent queue disordering 1928 * while sleeps in memcpy_tomsg 1929 */ 1930 1931 if (!siocb->scm) { 1932 siocb->scm = &tmp_scm; 1933 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1934 } 1935 1936 err = mutex_lock_interruptible(&u->readlock); 1937 if (err) { 1938 err = sock_intr_errno(timeo); 1939 goto out; 1940 } 1941 1942 skip = sk_peek_offset(sk, flags); 1943 1944 do { 1945 int chunk; 1946 struct sk_buff *skb; 1947 1948 unix_state_lock(sk); 1949 skb = skb_peek(&sk->sk_receive_queue); 1950again: 1951 if (skb == NULL) { 1952 unix_sk(sk)->recursion_level = 0; 1953 if (copied >= target) 1954 goto unlock; 1955 1956 /* 1957 * POSIX 1003.1g mandates this order. 1958 */ 1959 1960 err = sock_error(sk); 1961 if (err) 1962 goto unlock; 1963 if (sk->sk_shutdown & RCV_SHUTDOWN) 1964 goto unlock; 1965 1966 unix_state_unlock(sk); 1967 err = -EAGAIN; 1968 if (!timeo) 1969 break; 1970 mutex_unlock(&u->readlock); 1971 1972 timeo = unix_stream_data_wait(sk, timeo); 1973 1974 if (signal_pending(current) 1975 || mutex_lock_interruptible(&u->readlock)) { 1976 err = sock_intr_errno(timeo); 1977 goto out; 1978 } 1979 1980 continue; 1981 unlock: 1982 unix_state_unlock(sk); 1983 break; 1984 } 1985 1986 if (skip >= skb->len) { 1987 skip -= skb->len; 1988 skb = skb_peek_next(skb, &sk->sk_receive_queue); 1989 goto again; 1990 } 1991 1992 unix_state_unlock(sk); 1993 1994 if (check_creds) { 1995 /* Never glue messages from different writers */ 1996 if ((UNIXCB(skb).pid != siocb->scm->pid) || 1997 (UNIXCB(skb).cred != siocb->scm->cred)) 1998 break; 1999 } else { 2000 /* Copy credentials */ 2001 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 2002 check_creds = 1; 2003 } 2004 2005 /* Copy address just once */ 2006 if (sunaddr) { 2007 unix_copy_addr(msg, skb->sk); 2008 sunaddr = NULL; 2009 } 2010 2011 chunk = min_t(unsigned int, skb->len - skip, size); 2012 if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) { 2013 if (copied == 0) 2014 copied = -EFAULT; 2015 break; 2016 } 2017 copied += chunk; 2018 size -= chunk; 2019 2020 /* Mark read part of skb as used */ 2021 if (!(flags & MSG_PEEK)) { 2022 skb_pull(skb, chunk); 2023 2024 sk_peek_offset_bwd(sk, chunk); 2025 2026 if (UNIXCB(skb).fp) 2027 unix_detach_fds(siocb->scm, skb); 2028 2029 if (skb->len) 2030 break; 2031 2032 skb_unlink(skb, &sk->sk_receive_queue); 2033 consume_skb(skb); 2034 2035 if (siocb->scm->fp) 2036 break; 2037 } else { 2038 /* It is questionable, see note in unix_dgram_recvmsg. 2039 */ 2040 if (UNIXCB(skb).fp) 2041 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2042 2043 sk_peek_offset_fwd(sk, chunk); 2044 2045 break; 2046 } 2047 } while (size); 2048 2049 mutex_unlock(&u->readlock); 2050 scm_recv(sock, msg, siocb->scm, flags); 2051out: 2052 return copied ? : err; 2053} 2054 2055static int unix_shutdown(struct socket *sock, int mode) 2056{ 2057 struct sock *sk = sock->sk; 2058 struct sock *other; 2059 2060 if (mode < SHUT_RD || mode > SHUT_RDWR) 2061 return -EINVAL; 2062 /* This maps: 2063 * SHUT_RD (0) -> RCV_SHUTDOWN (1) 2064 * SHUT_WR (1) -> SEND_SHUTDOWN (2) 2065 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3) 2066 */ 2067 ++mode; 2068 2069 unix_state_lock(sk); 2070 sk->sk_shutdown |= mode; 2071 other = unix_peer(sk); 2072 if (other) 2073 sock_hold(other); 2074 unix_state_unlock(sk); 2075 sk->sk_state_change(sk); 2076 2077 if (other && 2078 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2079 2080 int peer_mode = 0; 2081 2082 if (mode&RCV_SHUTDOWN) 2083 peer_mode |= SEND_SHUTDOWN; 2084 if (mode&SEND_SHUTDOWN) 2085 peer_mode |= RCV_SHUTDOWN; 2086 unix_state_lock(other); 2087 other->sk_shutdown |= peer_mode; 2088 unix_state_unlock(other); 2089 other->sk_state_change(other); 2090 if (peer_mode == SHUTDOWN_MASK) 2091 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2092 else if (peer_mode & RCV_SHUTDOWN) 2093 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2094 } 2095 if (other) 2096 sock_put(other); 2097 2098 return 0; 2099} 2100 2101long unix_inq_len(struct sock *sk) 2102{ 2103 struct sk_buff *skb; 2104 long amount = 0; 2105 2106 if (sk->sk_state == TCP_LISTEN) 2107 return -EINVAL; 2108 2109 spin_lock(&sk->sk_receive_queue.lock); 2110 if (sk->sk_type == SOCK_STREAM || 2111 sk->sk_type == SOCK_SEQPACKET) { 2112 skb_queue_walk(&sk->sk_receive_queue, skb) 2113 amount += skb->len; 2114 } else { 2115 skb = skb_peek(&sk->sk_receive_queue); 2116 if (skb) 2117 amount = skb->len; 2118 } 2119 spin_unlock(&sk->sk_receive_queue.lock); 2120 2121 return amount; 2122} 2123EXPORT_SYMBOL_GPL(unix_inq_len); 2124 2125long unix_outq_len(struct sock *sk) 2126{ 2127 return sk_wmem_alloc_get(sk); 2128} 2129EXPORT_SYMBOL_GPL(unix_outq_len); 2130 2131static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2132{ 2133 struct sock *sk = sock->sk; 2134 long amount = 0; 2135 int err; 2136 2137 switch (cmd) { 2138 case SIOCOUTQ: 2139 amount = unix_outq_len(sk); 2140 err = put_user(amount, (int __user *)arg); 2141 break; 2142 case SIOCINQ: 2143 amount = unix_inq_len(sk); 2144 if (amount < 0) 2145 err = amount; 2146 else 2147 err = put_user(amount, (int __user *)arg); 2148 break; 2149 default: 2150 err = -ENOIOCTLCMD; 2151 break; 2152 } 2153 return err; 2154} 2155 2156static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2157{ 2158 struct sock *sk = sock->sk; 2159 unsigned int mask; 2160 2161 sock_poll_wait(file, sk_sleep(sk), wait); 2162 mask = 0; 2163 2164 /* exceptional events? */ 2165 if (sk->sk_err) 2166 mask |= POLLERR; 2167 if (sk->sk_shutdown == SHUTDOWN_MASK) 2168 mask |= POLLHUP; 2169 if (sk->sk_shutdown & RCV_SHUTDOWN) 2170 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2171 2172 /* readable? */ 2173 if (!skb_queue_empty(&sk->sk_receive_queue)) 2174 mask |= POLLIN | POLLRDNORM; 2175 2176 /* Connection-based need to check for termination and startup */ 2177 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2178 sk->sk_state == TCP_CLOSE) 2179 mask |= POLLHUP; 2180 2181 /* 2182 * we set writable also when the other side has shut down the 2183 * connection. This prevents stuck sockets. 2184 */ 2185 if (unix_writable(sk)) 2186 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2187 2188 return mask; 2189} 2190 2191static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2192 poll_table *wait) 2193{ 2194 struct sock *sk = sock->sk, *other; 2195 unsigned int mask, writable; 2196 2197 sock_poll_wait(file, sk_sleep(sk), wait); 2198 mask = 0; 2199 2200 /* exceptional events? */ 2201 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2202 mask |= POLLERR; 2203 if (sk->sk_shutdown & RCV_SHUTDOWN) 2204 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2205 if (sk->sk_shutdown == SHUTDOWN_MASK) 2206 mask |= POLLHUP; 2207 2208 /* readable? */ 2209 if (!skb_queue_empty(&sk->sk_receive_queue)) 2210 mask |= POLLIN | POLLRDNORM; 2211 2212 /* Connection-based need to check for termination and startup */ 2213 if (sk->sk_type == SOCK_SEQPACKET) { 2214 if (sk->sk_state == TCP_CLOSE) 2215 mask |= POLLHUP; 2216 /* connection hasn't started yet? */ 2217 if (sk->sk_state == TCP_SYN_SENT) 2218 return mask; 2219 } 2220 2221 /* No write status requested, avoid expensive OUT tests. */ 2222 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) 2223 return mask; 2224 2225 writable = unix_writable(sk); 2226 other = unix_peer_get(sk); 2227 if (other) { 2228 if (unix_peer(other) != sk) { 2229 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2230 if (unix_recvq_full(other)) 2231 writable = 0; 2232 } 2233 sock_put(other); 2234 } 2235 2236 if (writable) 2237 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2238 else 2239 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2240 2241 return mask; 2242} 2243 2244#ifdef CONFIG_PROC_FS 2245 2246#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) 2247 2248#define get_bucket(x) ((x) >> BUCKET_SPACE) 2249#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1)) 2250#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) 2251 2252static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) 2253{ 2254 unsigned long offset = get_offset(*pos); 2255 unsigned long bucket = get_bucket(*pos); 2256 struct sock *sk; 2257 unsigned long count = 0; 2258 2259 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) { 2260 if (sock_net(sk) != seq_file_net(seq)) 2261 continue; 2262 if (++count == offset) 2263 break; 2264 } 2265 2266 return sk; 2267} 2268 2269static struct sock *unix_next_socket(struct seq_file *seq, 2270 struct sock *sk, 2271 loff_t *pos) 2272{ 2273 unsigned long bucket; 2274 2275 while (sk > (struct sock *)SEQ_START_TOKEN) { 2276 sk = sk_next(sk); 2277 if (!sk) 2278 goto next_bucket; 2279 if (sock_net(sk) == seq_file_net(seq)) 2280 return sk; 2281 } 2282 2283 do { 2284 sk = unix_from_bucket(seq, pos); 2285 if (sk) 2286 return sk; 2287 2288next_bucket: 2289 bucket = get_bucket(*pos) + 1; 2290 *pos = set_bucket_offset(bucket, 1); 2291 } while (bucket < ARRAY_SIZE(unix_socket_table)); 2292 2293 return NULL; 2294} 2295 2296static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2297 __acquires(unix_table_lock) 2298{ 2299 spin_lock(&unix_table_lock); 2300 2301 if (!*pos) 2302 return SEQ_START_TOKEN; 2303 2304 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table)) 2305 return NULL; 2306 2307 return unix_next_socket(seq, NULL, pos); 2308} 2309 2310static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2311{ 2312 ++*pos; 2313 return unix_next_socket(seq, v, pos); 2314} 2315 2316static void unix_seq_stop(struct seq_file *seq, void *v) 2317 __releases(unix_table_lock) 2318{ 2319 spin_unlock(&unix_table_lock); 2320} 2321 2322static int unix_seq_show(struct seq_file *seq, void *v) 2323{ 2324 2325 if (v == SEQ_START_TOKEN) 2326 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2327 "Inode Path\n"); 2328 else { 2329 struct sock *s = v; 2330 struct unix_sock *u = unix_sk(s); 2331 unix_state_lock(s); 2332 2333 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2334 s, 2335 atomic_read(&s->sk_refcnt), 2336 0, 2337 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2338 s->sk_type, 2339 s->sk_socket ? 2340 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2341 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2342 sock_i_ino(s)); 2343 2344 if (u->addr) { 2345 int i, len; 2346 seq_putc(seq, ' '); 2347 2348 i = 0; 2349 len = u->addr->len - sizeof(short); 2350 if (!UNIX_ABSTRACT(s)) 2351 len--; 2352 else { 2353 seq_putc(seq, '@'); 2354 i++; 2355 } 2356 for ( ; i < len; i++) 2357 seq_putc(seq, u->addr->name->sun_path[i]); 2358 } 2359 unix_state_unlock(s); 2360 seq_putc(seq, '\n'); 2361 } 2362 2363 return 0; 2364} 2365 2366static const struct seq_operations unix_seq_ops = { 2367 .start = unix_seq_start, 2368 .next = unix_seq_next, 2369 .stop = unix_seq_stop, 2370 .show = unix_seq_show, 2371}; 2372 2373static int unix_seq_open(struct inode *inode, struct file *file) 2374{ 2375 return seq_open_net(inode, file, &unix_seq_ops, 2376 sizeof(struct seq_net_private)); 2377} 2378 2379static const struct file_operations unix_seq_fops = { 2380 .owner = THIS_MODULE, 2381 .open = unix_seq_open, 2382 .read = seq_read, 2383 .llseek = seq_lseek, 2384 .release = seq_release_net, 2385}; 2386 2387#endif 2388 2389static const struct net_proto_family unix_family_ops = { 2390 .family = PF_UNIX, 2391 .create = unix_create, 2392 .owner = THIS_MODULE, 2393}; 2394 2395 2396static int __net_init unix_net_init(struct net *net) 2397{ 2398 int error = -ENOMEM; 2399 2400 net->unx.sysctl_max_dgram_qlen = 10; 2401 if (unix_sysctl_register(net)) 2402 goto out; 2403 2404#ifdef CONFIG_PROC_FS 2405 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) { 2406 unix_sysctl_unregister(net); 2407 goto out; 2408 } 2409#endif 2410 error = 0; 2411out: 2412 return error; 2413} 2414 2415static void __net_exit unix_net_exit(struct net *net) 2416{ 2417 unix_sysctl_unregister(net); 2418 proc_net_remove(net, "unix"); 2419} 2420 2421static struct pernet_operations unix_net_ops = { 2422 .init = unix_net_init, 2423 .exit = unix_net_exit, 2424}; 2425 2426static int __init af_unix_init(void) 2427{ 2428 int rc = -1; 2429 2430 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2431 2432 rc = proto_register(&unix_proto, 1); 2433 if (rc != 0) { 2434 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2435 __func__); 2436 goto out; 2437 } 2438 2439 sock_register(&unix_family_ops); 2440 register_pernet_subsys(&unix_net_ops); 2441out: 2442 return rc; 2443} 2444 2445static void __exit af_unix_exit(void) 2446{ 2447 sock_unregister(PF_UNIX); 2448 proto_unregister(&unix_proto); 2449 unregister_pernet_subsys(&unix_net_ops); 2450} 2451 2452/* Earlier than device_initcall() so that other drivers invoking 2453 request_module() don't end up in a loop when modprobe tries 2454 to use a UNIX socket. But later than subsys_initcall() because 2455 we depend on stuff initialised there */ 2456fs_initcall(af_unix_init); 2457module_exit(af_unix_exit); 2458 2459MODULE_LICENSE("GPL"); 2460MODULE_ALIAS_NETPROTO(PF_UNIX); 2461