af_unix.c revision 8b51b064a6da90c68af5385a874968829a2a0ed7
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 use 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 const struct cred *old_cred = NULL; 485 486 err = -EOPNOTSUPP; 487 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 488 goto out; /* Only stream/seqpacket sockets accept */ 489 err = -EINVAL; 490 if (!u->addr) 491 goto out; /* No listens on an unbound socket */ 492 unix_state_lock(sk); 493 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 494 goto out_unlock; 495 if (backlog > sk->sk_max_ack_backlog) 496 wake_up_interruptible_all(&u->peer_wait); 497 sk->sk_max_ack_backlog = backlog; 498 sk->sk_state = TCP_LISTEN; 499 /* set credentials so connect can copy them */ 500 init_peercred(sk); 501 err = 0; 502 503out_unlock: 504 unix_state_unlock(sk); 505 put_pid(old_pid); 506 if (old_cred) 507 put_cred(old_cred); 508out: 509 return err; 510} 511 512static int unix_release(struct socket *); 513static int unix_bind(struct socket *, struct sockaddr *, int); 514static int unix_stream_connect(struct socket *, struct sockaddr *, 515 int addr_len, int flags); 516static int unix_socketpair(struct socket *, struct socket *); 517static int unix_accept(struct socket *, struct socket *, int); 518static int unix_getname(struct socket *, struct sockaddr *, int *, int); 519static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 520static unsigned int unix_dgram_poll(struct file *, struct socket *, 521 poll_table *); 522static int unix_ioctl(struct socket *, unsigned int, unsigned long); 523static int unix_shutdown(struct socket *, int); 524static int unix_stream_sendmsg(struct kiocb *, struct socket *, 525 struct msghdr *, size_t); 526static int unix_stream_recvmsg(struct kiocb *, struct socket *, 527 struct msghdr *, size_t, int); 528static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 529 struct msghdr *, size_t); 530static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 531 struct msghdr *, size_t, int); 532static int unix_dgram_connect(struct socket *, struct sockaddr *, 533 int, int); 534static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 535 struct msghdr *, size_t); 536static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *, 537 struct msghdr *, size_t, int); 538 539static void unix_set_peek_off(struct sock *sk, int val) 540{ 541 struct unix_sock *u = unix_sk(sk); 542 543 mutex_lock(&u->readlock); 544 sk->sk_peek_off = val; 545 mutex_unlock(&u->readlock); 546} 547 548 549static const struct proto_ops unix_stream_ops = { 550 .family = PF_UNIX, 551 .owner = THIS_MODULE, 552 .release = unix_release, 553 .bind = unix_bind, 554 .connect = unix_stream_connect, 555 .socketpair = unix_socketpair, 556 .accept = unix_accept, 557 .getname = unix_getname, 558 .poll = unix_poll, 559 .ioctl = unix_ioctl, 560 .listen = unix_listen, 561 .shutdown = unix_shutdown, 562 .setsockopt = sock_no_setsockopt, 563 .getsockopt = sock_no_getsockopt, 564 .sendmsg = unix_stream_sendmsg, 565 .recvmsg = unix_stream_recvmsg, 566 .mmap = sock_no_mmap, 567 .sendpage = sock_no_sendpage, 568 .set_peek_off = unix_set_peek_off, 569}; 570 571static const struct proto_ops unix_dgram_ops = { 572 .family = PF_UNIX, 573 .owner = THIS_MODULE, 574 .release = unix_release, 575 .bind = unix_bind, 576 .connect = unix_dgram_connect, 577 .socketpair = unix_socketpair, 578 .accept = sock_no_accept, 579 .getname = unix_getname, 580 .poll = unix_dgram_poll, 581 .ioctl = unix_ioctl, 582 .listen = sock_no_listen, 583 .shutdown = unix_shutdown, 584 .setsockopt = sock_no_setsockopt, 585 .getsockopt = sock_no_getsockopt, 586 .sendmsg = unix_dgram_sendmsg, 587 .recvmsg = unix_dgram_recvmsg, 588 .mmap = sock_no_mmap, 589 .sendpage = sock_no_sendpage, 590 .set_peek_off = unix_set_peek_off, 591}; 592 593static const struct proto_ops unix_seqpacket_ops = { 594 .family = PF_UNIX, 595 .owner = THIS_MODULE, 596 .release = unix_release, 597 .bind = unix_bind, 598 .connect = unix_stream_connect, 599 .socketpair = unix_socketpair, 600 .accept = unix_accept, 601 .getname = unix_getname, 602 .poll = unix_dgram_poll, 603 .ioctl = unix_ioctl, 604 .listen = unix_listen, 605 .shutdown = unix_shutdown, 606 .setsockopt = sock_no_setsockopt, 607 .getsockopt = sock_no_getsockopt, 608 .sendmsg = unix_seqpacket_sendmsg, 609 .recvmsg = unix_seqpacket_recvmsg, 610 .mmap = sock_no_mmap, 611 .sendpage = sock_no_sendpage, 612 .set_peek_off = unix_set_peek_off, 613}; 614 615static struct proto unix_proto = { 616 .name = "UNIX", 617 .owner = THIS_MODULE, 618 .obj_size = sizeof(struct unix_sock), 619}; 620 621/* 622 * AF_UNIX sockets do not interact with hardware, hence they 623 * dont trigger interrupts - so it's safe for them to have 624 * bh-unsafe locking for their sk_receive_queue.lock. Split off 625 * this special lock-class by reinitializing the spinlock key: 626 */ 627static struct lock_class_key af_unix_sk_receive_queue_lock_key; 628 629static struct sock *unix_create1(struct net *net, struct socket *sock) 630{ 631 struct sock *sk = NULL; 632 struct unix_sock *u; 633 634 atomic_long_inc(&unix_nr_socks); 635 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) 636 goto out; 637 638 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto); 639 if (!sk) 640 goto out; 641 642 sock_init_data(sock, sk); 643 lockdep_set_class(&sk->sk_receive_queue.lock, 644 &af_unix_sk_receive_queue_lock_key); 645 646 sk->sk_write_space = unix_write_space; 647 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; 648 sk->sk_destruct = unix_sock_destructor; 649 u = unix_sk(sk); 650 u->path.dentry = NULL; 651 u->path.mnt = NULL; 652 spin_lock_init(&u->lock); 653 atomic_long_set(&u->inflight, 0); 654 INIT_LIST_HEAD(&u->link); 655 mutex_init(&u->readlock); /* single task reading lock */ 656 init_waitqueue_head(&u->peer_wait); 657 unix_insert_socket(unix_sockets_unbound(sk), sk); 658out: 659 if (sk == NULL) 660 atomic_long_dec(&unix_nr_socks); 661 else { 662 local_bh_disable(); 663 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 664 local_bh_enable(); 665 } 666 return sk; 667} 668 669static int unix_create(struct net *net, struct socket *sock, int protocol, 670 int kern) 671{ 672 if (protocol && protocol != PF_UNIX) 673 return -EPROTONOSUPPORT; 674 675 sock->state = SS_UNCONNECTED; 676 677 switch (sock->type) { 678 case SOCK_STREAM: 679 sock->ops = &unix_stream_ops; 680 break; 681 /* 682 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 683 * nothing uses it. 684 */ 685 case SOCK_RAW: 686 sock->type = SOCK_DGRAM; 687 case SOCK_DGRAM: 688 sock->ops = &unix_dgram_ops; 689 break; 690 case SOCK_SEQPACKET: 691 sock->ops = &unix_seqpacket_ops; 692 break; 693 default: 694 return -ESOCKTNOSUPPORT; 695 } 696 697 return unix_create1(net, sock) ? 0 : -ENOMEM; 698} 699 700static int unix_release(struct socket *sock) 701{ 702 struct sock *sk = sock->sk; 703 704 if (!sk) 705 return 0; 706 707 sock->sk = NULL; 708 709 return unix_release_sock(sk, 0); 710} 711 712static int unix_autobind(struct socket *sock) 713{ 714 struct sock *sk = sock->sk; 715 struct net *net = sock_net(sk); 716 struct unix_sock *u = unix_sk(sk); 717 static u32 ordernum = 1; 718 struct unix_address *addr; 719 int err; 720 unsigned int retries = 0; 721 722 mutex_lock(&u->readlock); 723 724 err = 0; 725 if (u->addr) 726 goto out; 727 728 err = -ENOMEM; 729 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 730 if (!addr) 731 goto out; 732 733 addr->name->sun_family = AF_UNIX; 734 atomic_set(&addr->refcnt, 1); 735 736retry: 737 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 738 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0)); 739 740 spin_lock(&unix_table_lock); 741 ordernum = (ordernum+1)&0xFFFFF; 742 743 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type, 744 addr->hash)) { 745 spin_unlock(&unix_table_lock); 746 /* 747 * __unix_find_socket_byname() may take long time if many names 748 * are already in use. 749 */ 750 cond_resched(); 751 /* Give up if all names seems to be in use. */ 752 if (retries++ == 0xFFFFF) { 753 err = -ENOSPC; 754 kfree(addr); 755 goto out; 756 } 757 goto retry; 758 } 759 addr->hash ^= sk->sk_type; 760 761 __unix_remove_socket(sk); 762 u->addr = addr; 763 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 764 spin_unlock(&unix_table_lock); 765 err = 0; 766 767out: mutex_unlock(&u->readlock); 768 return err; 769} 770 771static struct sock *unix_find_other(struct net *net, 772 struct sockaddr_un *sunname, int len, 773 int type, unsigned int hash, int *error) 774{ 775 struct sock *u; 776 struct path path; 777 int err = 0; 778 779 if (sunname->sun_path[0]) { 780 struct inode *inode; 781 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); 782 if (err) 783 goto fail; 784 inode = path.dentry->d_inode; 785 err = inode_permission(inode, MAY_WRITE); 786 if (err) 787 goto put_fail; 788 789 err = -ECONNREFUSED; 790 if (!S_ISSOCK(inode->i_mode)) 791 goto put_fail; 792 u = unix_find_socket_byinode(inode); 793 if (!u) 794 goto put_fail; 795 796 if (u->sk_type == type) 797 touch_atime(&path); 798 799 path_put(&path); 800 801 err = -EPROTOTYPE; 802 if (u->sk_type != type) { 803 sock_put(u); 804 goto fail; 805 } 806 } else { 807 err = -ECONNREFUSED; 808 u = unix_find_socket_byname(net, sunname, len, type, hash); 809 if (u) { 810 struct dentry *dentry; 811 dentry = unix_sk(u)->path.dentry; 812 if (dentry) 813 touch_atime(&unix_sk(u)->path); 814 } else 815 goto fail; 816 } 817 return u; 818 819put_fail: 820 path_put(&path); 821fail: 822 *error = err; 823 return NULL; 824} 825 826 827static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 828{ 829 struct sock *sk = sock->sk; 830 struct net *net = sock_net(sk); 831 struct unix_sock *u = unix_sk(sk); 832 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 833 char *sun_path = sunaddr->sun_path; 834 struct dentry *dentry = NULL; 835 struct path path; 836 int err; 837 unsigned int hash; 838 struct unix_address *addr; 839 struct hlist_head *list; 840 841 err = -EINVAL; 842 if (sunaddr->sun_family != AF_UNIX) 843 goto out; 844 845 if (addr_len == sizeof(short)) { 846 err = unix_autobind(sock); 847 goto out; 848 } 849 850 err = unix_mkname(sunaddr, addr_len, &hash); 851 if (err < 0) 852 goto out; 853 addr_len = err; 854 855 mutex_lock(&u->readlock); 856 857 err = -EINVAL; 858 if (u->addr) 859 goto out_up; 860 861 err = -ENOMEM; 862 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 863 if (!addr) 864 goto out_up; 865 866 memcpy(addr->name, sunaddr, addr_len); 867 addr->len = addr_len; 868 addr->hash = hash ^ sk->sk_type; 869 atomic_set(&addr->refcnt, 1); 870 871 if (sun_path[0]) { 872 umode_t mode; 873 err = 0; 874 /* 875 * Get the parent directory, calculate the hash for last 876 * component. 877 */ 878 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0); 879 err = PTR_ERR(dentry); 880 if (IS_ERR(dentry)) 881 goto out_mknod_parent; 882 883 /* 884 * All right, let's create it. 885 */ 886 mode = S_IFSOCK | 887 (SOCK_INODE(sock)->i_mode & ~current_umask()); 888 err = mnt_want_write(path.mnt); 889 if (err) 890 goto out_mknod_dput; 891 err = security_path_mknod(&path, dentry, mode, 0); 892 if (err) 893 goto out_mknod_drop_write; 894 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0); 895out_mknod_drop_write: 896 mnt_drop_write(path.mnt); 897 if (err) 898 goto out_mknod_dput; 899 mutex_unlock(&path.dentry->d_inode->i_mutex); 900 dput(path.dentry); 901 path.dentry = dentry; 902 903 addr->hash = UNIX_HASH_SIZE; 904 } 905 906 spin_lock(&unix_table_lock); 907 908 if (!sun_path[0]) { 909 err = -EADDRINUSE; 910 if (__unix_find_socket_byname(net, sunaddr, addr_len, 911 sk->sk_type, hash)) { 912 unix_release_addr(addr); 913 goto out_unlock; 914 } 915 916 list = &unix_socket_table[addr->hash]; 917 } else { 918 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)]; 919 u->path = path; 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 934out_mknod_dput: 935 dput(dentry); 936 mutex_unlock(&path.dentry->d_inode->i_mutex); 937 path_put(&path); 938out_mknod_parent: 939 if (err == -EEXIST) 940 err = -EADDRINUSE; 941 unix_release_addr(addr); 942 goto out_up; 943} 944 945static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) 946{ 947 if (unlikely(sk1 == sk2) || !sk2) { 948 unix_state_lock(sk1); 949 return; 950 } 951 if (sk1 < sk2) { 952 unix_state_lock(sk1); 953 unix_state_lock_nested(sk2); 954 } else { 955 unix_state_lock(sk2); 956 unix_state_lock_nested(sk1); 957 } 958} 959 960static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) 961{ 962 if (unlikely(sk1 == sk2) || !sk2) { 963 unix_state_unlock(sk1); 964 return; 965 } 966 unix_state_unlock(sk1); 967 unix_state_unlock(sk2); 968} 969 970static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 971 int alen, int flags) 972{ 973 struct sock *sk = sock->sk; 974 struct net *net = sock_net(sk); 975 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; 976 struct sock *other; 977 unsigned int hash; 978 int err; 979 980 if (addr->sa_family != AF_UNSPEC) { 981 err = unix_mkname(sunaddr, alen, &hash); 982 if (err < 0) 983 goto out; 984 alen = err; 985 986 if (test_bit(SOCK_PASSCRED, &sock->flags) && 987 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 988 goto out; 989 990restart: 991 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); 992 if (!other) 993 goto out; 994 995 unix_state_double_lock(sk, other); 996 997 /* Apparently VFS overslept socket death. Retry. */ 998 if (sock_flag(other, SOCK_DEAD)) { 999 unix_state_double_unlock(sk, other); 1000 sock_put(other); 1001 goto restart; 1002 } 1003 1004 err = -EPERM; 1005 if (!unix_may_send(sk, other)) 1006 goto out_unlock; 1007 1008 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1009 if (err) 1010 goto out_unlock; 1011 1012 } else { 1013 /* 1014 * 1003.1g breaking connected state with AF_UNSPEC 1015 */ 1016 other = NULL; 1017 unix_state_double_lock(sk, other); 1018 } 1019 1020 /* 1021 * If it was connected, reconnect. 1022 */ 1023 if (unix_peer(sk)) { 1024 struct sock *old_peer = unix_peer(sk); 1025 unix_peer(sk) = other; 1026 unix_state_double_unlock(sk, other); 1027 1028 if (other != old_peer) 1029 unix_dgram_disconnected(sk, old_peer); 1030 sock_put(old_peer); 1031 } else { 1032 unix_peer(sk) = other; 1033 unix_state_double_unlock(sk, other); 1034 } 1035 return 0; 1036 1037out_unlock: 1038 unix_state_double_unlock(sk, other); 1039 sock_put(other); 1040out: 1041 return err; 1042} 1043 1044static long unix_wait_for_peer(struct sock *other, long timeo) 1045{ 1046 struct unix_sock *u = unix_sk(other); 1047 int sched; 1048 DEFINE_WAIT(wait); 1049 1050 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 1051 1052 sched = !sock_flag(other, SOCK_DEAD) && 1053 !(other->sk_shutdown & RCV_SHUTDOWN) && 1054 unix_recvq_full(other); 1055 1056 unix_state_unlock(other); 1057 1058 if (sched) 1059 timeo = schedule_timeout(timeo); 1060 1061 finish_wait(&u->peer_wait, &wait); 1062 return timeo; 1063} 1064 1065static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 1066 int addr_len, int flags) 1067{ 1068 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 1069 struct sock *sk = sock->sk; 1070 struct net *net = sock_net(sk); 1071 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 1072 struct sock *newsk = NULL; 1073 struct sock *other = NULL; 1074 struct sk_buff *skb = NULL; 1075 unsigned int hash; 1076 int st; 1077 int err; 1078 long timeo; 1079 1080 err = unix_mkname(sunaddr, addr_len, &hash); 1081 if (err < 0) 1082 goto out; 1083 addr_len = err; 1084 1085 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && 1086 (err = unix_autobind(sock)) != 0) 1087 goto out; 1088 1089 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 1090 1091 /* First of all allocate resources. 1092 If we will make it after state is locked, 1093 we will have to recheck all again in any case. 1094 */ 1095 1096 err = -ENOMEM; 1097 1098 /* create new sock for complete connection */ 1099 newsk = unix_create1(sock_net(sk), NULL); 1100 if (newsk == NULL) 1101 goto out; 1102 1103 /* Allocate skb for sending to listening sock */ 1104 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 1105 if (skb == NULL) 1106 goto out; 1107 1108restart: 1109 /* Find listening sock. */ 1110 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); 1111 if (!other) 1112 goto out; 1113 1114 /* Latch state of peer */ 1115 unix_state_lock(other); 1116 1117 /* Apparently VFS overslept socket death. Retry. */ 1118 if (sock_flag(other, SOCK_DEAD)) { 1119 unix_state_unlock(other); 1120 sock_put(other); 1121 goto restart; 1122 } 1123 1124 err = -ECONNREFUSED; 1125 if (other->sk_state != TCP_LISTEN) 1126 goto out_unlock; 1127 if (other->sk_shutdown & RCV_SHUTDOWN) 1128 goto out_unlock; 1129 1130 if (unix_recvq_full(other)) { 1131 err = -EAGAIN; 1132 if (!timeo) 1133 goto out_unlock; 1134 1135 timeo = unix_wait_for_peer(other, timeo); 1136 1137 err = sock_intr_errno(timeo); 1138 if (signal_pending(current)) 1139 goto out; 1140 sock_put(other); 1141 goto restart; 1142 } 1143 1144 /* Latch our state. 1145 1146 It is tricky place. We need to grab our state lock and cannot 1147 drop lock on peer. It is dangerous because deadlock is 1148 possible. Connect to self case and simultaneous 1149 attempt to connect are eliminated by checking socket 1150 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1151 check this before attempt to grab lock. 1152 1153 Well, and we have to recheck the state after socket locked. 1154 */ 1155 st = sk->sk_state; 1156 1157 switch (st) { 1158 case TCP_CLOSE: 1159 /* This is ok... continue with connect */ 1160 break; 1161 case TCP_ESTABLISHED: 1162 /* Socket is already connected */ 1163 err = -EISCONN; 1164 goto out_unlock; 1165 default: 1166 err = -EINVAL; 1167 goto out_unlock; 1168 } 1169 1170 unix_state_lock_nested(sk); 1171 1172 if (sk->sk_state != st) { 1173 unix_state_unlock(sk); 1174 unix_state_unlock(other); 1175 sock_put(other); 1176 goto restart; 1177 } 1178 1179 err = security_unix_stream_connect(sk, other, newsk); 1180 if (err) { 1181 unix_state_unlock(sk); 1182 goto out_unlock; 1183 } 1184 1185 /* The way is open! Fastly set all the necessary fields... */ 1186 1187 sock_hold(sk); 1188 unix_peer(newsk) = sk; 1189 newsk->sk_state = TCP_ESTABLISHED; 1190 newsk->sk_type = sk->sk_type; 1191 init_peercred(newsk); 1192 newu = unix_sk(newsk); 1193 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); 1194 otheru = unix_sk(other); 1195 1196 /* copy address information from listening to new sock*/ 1197 if (otheru->addr) { 1198 atomic_inc(&otheru->addr->refcnt); 1199 newu->addr = otheru->addr; 1200 } 1201 if (otheru->path.dentry) { 1202 path_get(&otheru->path); 1203 newu->path = otheru->path; 1204 } 1205 1206 /* Set credentials */ 1207 copy_peercred(sk, other); 1208 1209 sock->state = SS_CONNECTED; 1210 sk->sk_state = TCP_ESTABLISHED; 1211 sock_hold(newsk); 1212 1213 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1214 unix_peer(sk) = newsk; 1215 1216 unix_state_unlock(sk); 1217 1218 /* take ten and and send info to listening sock */ 1219 spin_lock(&other->sk_receive_queue.lock); 1220 __skb_queue_tail(&other->sk_receive_queue, skb); 1221 spin_unlock(&other->sk_receive_queue.lock); 1222 unix_state_unlock(other); 1223 other->sk_data_ready(other, 0); 1224 sock_put(other); 1225 return 0; 1226 1227out_unlock: 1228 if (other) 1229 unix_state_unlock(other); 1230 1231out: 1232 kfree_skb(skb); 1233 if (newsk) 1234 unix_release_sock(newsk, 0); 1235 if (other) 1236 sock_put(other); 1237 return err; 1238} 1239 1240static int unix_socketpair(struct socket *socka, struct socket *sockb) 1241{ 1242 struct sock *ska = socka->sk, *skb = sockb->sk; 1243 1244 /* Join our sockets back to back */ 1245 sock_hold(ska); 1246 sock_hold(skb); 1247 unix_peer(ska) = skb; 1248 unix_peer(skb) = ska; 1249 init_peercred(ska); 1250 init_peercred(skb); 1251 1252 if (ska->sk_type != SOCK_DGRAM) { 1253 ska->sk_state = TCP_ESTABLISHED; 1254 skb->sk_state = TCP_ESTABLISHED; 1255 socka->state = SS_CONNECTED; 1256 sockb->state = SS_CONNECTED; 1257 } 1258 return 0; 1259} 1260 1261static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1262{ 1263 struct sock *sk = sock->sk; 1264 struct sock *tsk; 1265 struct sk_buff *skb; 1266 int err; 1267 1268 err = -EOPNOTSUPP; 1269 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 1270 goto out; 1271 1272 err = -EINVAL; 1273 if (sk->sk_state != TCP_LISTEN) 1274 goto out; 1275 1276 /* If socket state is TCP_LISTEN it cannot change (for now...), 1277 * so that no locks are necessary. 1278 */ 1279 1280 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1281 if (!skb) { 1282 /* This means receive shutdown. */ 1283 if (err == 0) 1284 err = -EINVAL; 1285 goto out; 1286 } 1287 1288 tsk = skb->sk; 1289 skb_free_datagram(sk, skb); 1290 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1291 1292 /* attach accepted sock to socket */ 1293 unix_state_lock(tsk); 1294 newsock->state = SS_CONNECTED; 1295 sock_graft(tsk, newsock); 1296 unix_state_unlock(tsk); 1297 return 0; 1298 1299out: 1300 return err; 1301} 1302 1303 1304static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1305{ 1306 struct sock *sk = sock->sk; 1307 struct unix_sock *u; 1308 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); 1309 int err = 0; 1310 1311 if (peer) { 1312 sk = unix_peer_get(sk); 1313 1314 err = -ENOTCONN; 1315 if (!sk) 1316 goto out; 1317 err = 0; 1318 } else { 1319 sock_hold(sk); 1320 } 1321 1322 u = unix_sk(sk); 1323 unix_state_lock(sk); 1324 if (!u->addr) { 1325 sunaddr->sun_family = AF_UNIX; 1326 sunaddr->sun_path[0] = 0; 1327 *uaddr_len = sizeof(short); 1328 } else { 1329 struct unix_address *addr = u->addr; 1330 1331 *uaddr_len = addr->len; 1332 memcpy(sunaddr, addr->name, *uaddr_len); 1333 } 1334 unix_state_unlock(sk); 1335 sock_put(sk); 1336out: 1337 return err; 1338} 1339 1340static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1341{ 1342 int i; 1343 1344 scm->fp = UNIXCB(skb).fp; 1345 UNIXCB(skb).fp = NULL; 1346 1347 for (i = scm->fp->count-1; i >= 0; i--) 1348 unix_notinflight(scm->fp->fp[i]); 1349} 1350 1351static void unix_destruct_scm(struct sk_buff *skb) 1352{ 1353 struct scm_cookie scm; 1354 memset(&scm, 0, sizeof(scm)); 1355 scm.pid = UNIXCB(skb).pid; 1356 scm.cred = UNIXCB(skb).cred; 1357 if (UNIXCB(skb).fp) 1358 unix_detach_fds(&scm, skb); 1359 1360 /* Alas, it calls VFS */ 1361 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1362 scm_destroy(&scm); 1363 sock_wfree(skb); 1364} 1365 1366#define MAX_RECURSION_LEVEL 4 1367 1368static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1369{ 1370 int i; 1371 unsigned char max_level = 0; 1372 int unix_sock_count = 0; 1373 1374 for (i = scm->fp->count - 1; i >= 0; i--) { 1375 struct sock *sk = unix_get_socket(scm->fp->fp[i]); 1376 1377 if (sk) { 1378 unix_sock_count++; 1379 max_level = max(max_level, 1380 unix_sk(sk)->recursion_level); 1381 } 1382 } 1383 if (unlikely(max_level > MAX_RECURSION_LEVEL)) 1384 return -ETOOMANYREFS; 1385 1386 /* 1387 * Need to duplicate file references for the sake of garbage 1388 * collection. Otherwise a socket in the fps might become a 1389 * candidate for GC while the skb is not yet queued. 1390 */ 1391 UNIXCB(skb).fp = scm_fp_dup(scm->fp); 1392 if (!UNIXCB(skb).fp) 1393 return -ENOMEM; 1394 1395 if (unix_sock_count) { 1396 for (i = scm->fp->count - 1; i >= 0; i--) 1397 unix_inflight(scm->fp->fp[i]); 1398 } 1399 return max_level; 1400} 1401 1402static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) 1403{ 1404 int err = 0; 1405 1406 UNIXCB(skb).pid = get_pid(scm->pid); 1407 if (scm->cred) 1408 UNIXCB(skb).cred = get_cred(scm->cred); 1409 UNIXCB(skb).fp = NULL; 1410 if (scm->fp && send_fds) 1411 err = unix_attach_fds(scm, skb); 1412 1413 skb->destructor = unix_destruct_scm; 1414 return err; 1415} 1416 1417/* 1418 * Some apps rely on write() giving SCM_CREDENTIALS 1419 * We include credentials if source or destination socket 1420 * asserted SOCK_PASSCRED. 1421 */ 1422static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, 1423 const struct sock *other) 1424{ 1425 if (UNIXCB(skb).cred) 1426 return; 1427 if (test_bit(SOCK_PASSCRED, &sock->flags) || 1428 !other->sk_socket || 1429 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { 1430 UNIXCB(skb).pid = get_pid(task_tgid(current)); 1431 UNIXCB(skb).cred = get_current_cred(); 1432 } 1433} 1434 1435/* 1436 * Send AF_UNIX data. 1437 */ 1438 1439static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1440 struct msghdr *msg, size_t len) 1441{ 1442 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1443 struct sock *sk = sock->sk; 1444 struct net *net = sock_net(sk); 1445 struct unix_sock *u = unix_sk(sk); 1446 struct sockaddr_un *sunaddr = msg->msg_name; 1447 struct sock *other = NULL; 1448 int namelen = 0; /* fake GCC */ 1449 int err; 1450 unsigned int hash; 1451 struct sk_buff *skb; 1452 long timeo; 1453 struct scm_cookie tmp_scm; 1454 int max_level; 1455 int data_len = 0; 1456 1457 if (NULL == siocb->scm) 1458 siocb->scm = &tmp_scm; 1459 wait_for_unix_gc(); 1460 err = scm_send(sock, msg, siocb->scm); 1461 if (err < 0) 1462 return err; 1463 1464 err = -EOPNOTSUPP; 1465 if (msg->msg_flags&MSG_OOB) 1466 goto out; 1467 1468 if (msg->msg_namelen) { 1469 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1470 if (err < 0) 1471 goto out; 1472 namelen = err; 1473 } else { 1474 sunaddr = NULL; 1475 err = -ENOTCONN; 1476 other = unix_peer_get(sk); 1477 if (!other) 1478 goto out; 1479 } 1480 1481 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr 1482 && (err = unix_autobind(sock)) != 0) 1483 goto out; 1484 1485 err = -EMSGSIZE; 1486 if (len > sk->sk_sndbuf - 32) 1487 goto out; 1488 1489 if (len > SKB_MAX_ALLOC) 1490 data_len = min_t(size_t, 1491 len - SKB_MAX_ALLOC, 1492 MAX_SKB_FRAGS * PAGE_SIZE); 1493 1494 skb = sock_alloc_send_pskb(sk, len - data_len, data_len, 1495 msg->msg_flags & MSG_DONTWAIT, &err); 1496 if (skb == NULL) 1497 goto out; 1498 1499 err = unix_scm_to_skb(siocb->scm, skb, true); 1500 if (err < 0) 1501 goto out_free; 1502 max_level = err + 1; 1503 unix_get_secdata(siocb->scm, skb); 1504 1505 skb_put(skb, len - data_len); 1506 skb->data_len = data_len; 1507 skb->len = len; 1508 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len); 1509 if (err) 1510 goto out_free; 1511 1512 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1513 1514restart: 1515 if (!other) { 1516 err = -ECONNRESET; 1517 if (sunaddr == NULL) 1518 goto out_free; 1519 1520 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1521 hash, &err); 1522 if (other == NULL) 1523 goto out_free; 1524 } 1525 1526 if (sk_filter(other, skb) < 0) { 1527 /* Toss the packet but do not return any error to the sender */ 1528 err = len; 1529 goto out_free; 1530 } 1531 1532 unix_state_lock(other); 1533 err = -EPERM; 1534 if (!unix_may_send(sk, other)) 1535 goto out_unlock; 1536 1537 if (sock_flag(other, SOCK_DEAD)) { 1538 /* 1539 * Check with 1003.1g - what should 1540 * datagram error 1541 */ 1542 unix_state_unlock(other); 1543 sock_put(other); 1544 1545 err = 0; 1546 unix_state_lock(sk); 1547 if (unix_peer(sk) == other) { 1548 unix_peer(sk) = NULL; 1549 unix_state_unlock(sk); 1550 1551 unix_dgram_disconnected(sk, other); 1552 sock_put(other); 1553 err = -ECONNREFUSED; 1554 } else { 1555 unix_state_unlock(sk); 1556 } 1557 1558 other = NULL; 1559 if (err) 1560 goto out_free; 1561 goto restart; 1562 } 1563 1564 err = -EPIPE; 1565 if (other->sk_shutdown & RCV_SHUTDOWN) 1566 goto out_unlock; 1567 1568 if (sk->sk_type != SOCK_SEQPACKET) { 1569 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1570 if (err) 1571 goto out_unlock; 1572 } 1573 1574 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1575 if (!timeo) { 1576 err = -EAGAIN; 1577 goto out_unlock; 1578 } 1579 1580 timeo = unix_wait_for_peer(other, timeo); 1581 1582 err = sock_intr_errno(timeo); 1583 if (signal_pending(current)) 1584 goto out_free; 1585 1586 goto restart; 1587 } 1588 1589 if (sock_flag(other, SOCK_RCVTSTAMP)) 1590 __net_timestamp(skb); 1591 maybe_add_creds(skb, sock, other); 1592 skb_queue_tail(&other->sk_receive_queue, skb); 1593 if (max_level > unix_sk(other)->recursion_level) 1594 unix_sk(other)->recursion_level = max_level; 1595 unix_state_unlock(other); 1596 other->sk_data_ready(other, len); 1597 sock_put(other); 1598 scm_destroy(siocb->scm); 1599 return len; 1600 1601out_unlock: 1602 unix_state_unlock(other); 1603out_free: 1604 kfree_skb(skb); 1605out: 1606 if (other) 1607 sock_put(other); 1608 scm_destroy(siocb->scm); 1609 return err; 1610} 1611 1612 1613static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1614 struct msghdr *msg, size_t len) 1615{ 1616 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1617 struct sock *sk = sock->sk; 1618 struct sock *other = NULL; 1619 int err, size; 1620 struct sk_buff *skb; 1621 int sent = 0; 1622 struct scm_cookie tmp_scm; 1623 bool fds_sent = false; 1624 int max_level; 1625 1626 if (NULL == siocb->scm) 1627 siocb->scm = &tmp_scm; 1628 wait_for_unix_gc(); 1629 err = scm_send(sock, msg, siocb->scm); 1630 if (err < 0) 1631 return err; 1632 1633 err = -EOPNOTSUPP; 1634 if (msg->msg_flags&MSG_OOB) 1635 goto out_err; 1636 1637 if (msg->msg_namelen) { 1638 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1639 goto out_err; 1640 } else { 1641 err = -ENOTCONN; 1642 other = unix_peer(sk); 1643 if (!other) 1644 goto out_err; 1645 } 1646 1647 if (sk->sk_shutdown & SEND_SHUTDOWN) 1648 goto pipe_err; 1649 1650 while (sent < len) { 1651 /* 1652 * Optimisation for the fact that under 0.01% of X 1653 * messages typically need breaking up. 1654 */ 1655 1656 size = len-sent; 1657 1658 /* Keep two messages in the pipe so it schedules better */ 1659 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1660 size = (sk->sk_sndbuf >> 1) - 64; 1661 1662 if (size > SKB_MAX_ALLOC) 1663 size = SKB_MAX_ALLOC; 1664 1665 /* 1666 * Grab a buffer 1667 */ 1668 1669 skb = sock_alloc_send_skb(sk, size, msg->msg_flags&MSG_DONTWAIT, 1670 &err); 1671 1672 if (skb == NULL) 1673 goto out_err; 1674 1675 /* 1676 * If you pass two values to the sock_alloc_send_skb 1677 * it tries to grab the large buffer with GFP_NOFS 1678 * (which can fail easily), and if it fails grab the 1679 * fallback size buffer which is under a page and will 1680 * succeed. [Alan] 1681 */ 1682 size = min_t(int, size, skb_tailroom(skb)); 1683 1684 1685 /* Only send the fds in the first buffer */ 1686 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1687 if (err < 0) { 1688 kfree_skb(skb); 1689 goto out_err; 1690 } 1691 max_level = err + 1; 1692 fds_sent = true; 1693 1694 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size); 1695 if (err) { 1696 kfree_skb(skb); 1697 goto out_err; 1698 } 1699 1700 unix_state_lock(other); 1701 1702 if (sock_flag(other, SOCK_DEAD) || 1703 (other->sk_shutdown & RCV_SHUTDOWN)) 1704 goto pipe_err_free; 1705 1706 maybe_add_creds(skb, sock, other); 1707 skb_queue_tail(&other->sk_receive_queue, skb); 1708 if (max_level > unix_sk(other)->recursion_level) 1709 unix_sk(other)->recursion_level = max_level; 1710 unix_state_unlock(other); 1711 other->sk_data_ready(other, size); 1712 sent += size; 1713 } 1714 1715 scm_destroy(siocb->scm); 1716 siocb->scm = NULL; 1717 1718 return sent; 1719 1720pipe_err_free: 1721 unix_state_unlock(other); 1722 kfree_skb(skb); 1723pipe_err: 1724 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1725 send_sig(SIGPIPE, current, 0); 1726 err = -EPIPE; 1727out_err: 1728 scm_destroy(siocb->scm); 1729 siocb->scm = NULL; 1730 return sent ? : err; 1731} 1732 1733static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1734 struct msghdr *msg, size_t len) 1735{ 1736 int err; 1737 struct sock *sk = sock->sk; 1738 1739 err = sock_error(sk); 1740 if (err) 1741 return err; 1742 1743 if (sk->sk_state != TCP_ESTABLISHED) 1744 return -ENOTCONN; 1745 1746 if (msg->msg_namelen) 1747 msg->msg_namelen = 0; 1748 1749 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1750} 1751 1752static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1753 struct msghdr *msg, size_t size, 1754 int flags) 1755{ 1756 struct sock *sk = sock->sk; 1757 1758 if (sk->sk_state != TCP_ESTABLISHED) 1759 return -ENOTCONN; 1760 1761 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1762} 1763 1764static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1765{ 1766 struct unix_sock *u = unix_sk(sk); 1767 1768 msg->msg_namelen = 0; 1769 if (u->addr) { 1770 msg->msg_namelen = u->addr->len; 1771 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1772 } 1773} 1774 1775static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1776 struct msghdr *msg, size_t size, 1777 int flags) 1778{ 1779 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1780 struct scm_cookie tmp_scm; 1781 struct sock *sk = sock->sk; 1782 struct unix_sock *u = unix_sk(sk); 1783 int noblock = flags & MSG_DONTWAIT; 1784 struct sk_buff *skb; 1785 int err; 1786 int peeked, skip; 1787 1788 err = -EOPNOTSUPP; 1789 if (flags&MSG_OOB) 1790 goto out; 1791 1792 msg->msg_namelen = 0; 1793 1794 err = mutex_lock_interruptible(&u->readlock); 1795 if (err) { 1796 err = sock_intr_errno(sock_rcvtimeo(sk, noblock)); 1797 goto out; 1798 } 1799 1800 skip = sk_peek_offset(sk, flags); 1801 1802 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); 1803 if (!skb) { 1804 unix_state_lock(sk); 1805 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1806 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1807 (sk->sk_shutdown & RCV_SHUTDOWN)) 1808 err = 0; 1809 unix_state_unlock(sk); 1810 goto out_unlock; 1811 } 1812 1813 wake_up_interruptible_sync_poll(&u->peer_wait, 1814 POLLOUT | POLLWRNORM | POLLWRBAND); 1815 1816 if (msg->msg_name) 1817 unix_copy_addr(msg, skb->sk); 1818 1819 if (size > skb->len - skip) 1820 size = skb->len - skip; 1821 else if (size < skb->len - skip) 1822 msg->msg_flags |= MSG_TRUNC; 1823 1824 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size); 1825 if (err) 1826 goto out_free; 1827 1828 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1829 __sock_recv_timestamp(msg, sk, skb); 1830 1831 if (!siocb->scm) { 1832 siocb->scm = &tmp_scm; 1833 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1834 } 1835 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 1836 unix_set_secdata(siocb->scm, skb); 1837 1838 if (!(flags & MSG_PEEK)) { 1839 if (UNIXCB(skb).fp) 1840 unix_detach_fds(siocb->scm, skb); 1841 1842 sk_peek_offset_bwd(sk, skb->len); 1843 } else { 1844 /* It is questionable: on PEEK we could: 1845 - do not return fds - good, but too simple 8) 1846 - return fds, and do not return them on read (old strategy, 1847 apparently wrong) 1848 - clone fds (I chose it for now, it is the most universal 1849 solution) 1850 1851 POSIX 1003.1g does not actually define this clearly 1852 at all. POSIX 1003.1g doesn't define a lot of things 1853 clearly however! 1854 1855 */ 1856 1857 sk_peek_offset_fwd(sk, size); 1858 1859 if (UNIXCB(skb).fp) 1860 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1861 } 1862 err = (flags & MSG_TRUNC) ? skb->len - skip : size; 1863 1864 scm_recv(sock, msg, siocb->scm, flags); 1865 1866out_free: 1867 skb_free_datagram(sk, skb); 1868out_unlock: 1869 mutex_unlock(&u->readlock); 1870out: 1871 return err; 1872} 1873 1874/* 1875 * Sleep until data has arrive. But check for races.. 1876 */ 1877 1878static long unix_stream_data_wait(struct sock *sk, long timeo) 1879{ 1880 DEFINE_WAIT(wait); 1881 1882 unix_state_lock(sk); 1883 1884 for (;;) { 1885 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1886 1887 if (!skb_queue_empty(&sk->sk_receive_queue) || 1888 sk->sk_err || 1889 (sk->sk_shutdown & RCV_SHUTDOWN) || 1890 signal_pending(current) || 1891 !timeo) 1892 break; 1893 1894 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1895 unix_state_unlock(sk); 1896 timeo = schedule_timeout(timeo); 1897 unix_state_lock(sk); 1898 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1899 } 1900 1901 finish_wait(sk_sleep(sk), &wait); 1902 unix_state_unlock(sk); 1903 return timeo; 1904} 1905 1906 1907 1908static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1909 struct msghdr *msg, size_t size, 1910 int flags) 1911{ 1912 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1913 struct scm_cookie tmp_scm; 1914 struct sock *sk = sock->sk; 1915 struct unix_sock *u = unix_sk(sk); 1916 struct sockaddr_un *sunaddr = msg->msg_name; 1917 int copied = 0; 1918 int check_creds = 0; 1919 int target; 1920 int err = 0; 1921 long timeo; 1922 int skip; 1923 1924 err = -EINVAL; 1925 if (sk->sk_state != TCP_ESTABLISHED) 1926 goto out; 1927 1928 err = -EOPNOTSUPP; 1929 if (flags&MSG_OOB) 1930 goto out; 1931 1932 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1933 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1934 1935 msg->msg_namelen = 0; 1936 1937 /* Lock the socket to prevent queue disordering 1938 * while sleeps in memcpy_tomsg 1939 */ 1940 1941 if (!siocb->scm) { 1942 siocb->scm = &tmp_scm; 1943 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1944 } 1945 1946 err = mutex_lock_interruptible(&u->readlock); 1947 if (err) { 1948 err = sock_intr_errno(timeo); 1949 goto out; 1950 } 1951 1952 skip = sk_peek_offset(sk, flags); 1953 1954 do { 1955 int chunk; 1956 struct sk_buff *skb; 1957 1958 unix_state_lock(sk); 1959 skb = skb_peek(&sk->sk_receive_queue); 1960again: 1961 if (skb == NULL) { 1962 unix_sk(sk)->recursion_level = 0; 1963 if (copied >= target) 1964 goto unlock; 1965 1966 /* 1967 * POSIX 1003.1g mandates this order. 1968 */ 1969 1970 err = sock_error(sk); 1971 if (err) 1972 goto unlock; 1973 if (sk->sk_shutdown & RCV_SHUTDOWN) 1974 goto unlock; 1975 1976 unix_state_unlock(sk); 1977 err = -EAGAIN; 1978 if (!timeo) 1979 break; 1980 mutex_unlock(&u->readlock); 1981 1982 timeo = unix_stream_data_wait(sk, timeo); 1983 1984 if (signal_pending(current) 1985 || mutex_lock_interruptible(&u->readlock)) { 1986 err = sock_intr_errno(timeo); 1987 goto out; 1988 } 1989 1990 continue; 1991 unlock: 1992 unix_state_unlock(sk); 1993 break; 1994 } 1995 1996 if (skip >= skb->len) { 1997 skip -= skb->len; 1998 skb = skb_peek_next(skb, &sk->sk_receive_queue); 1999 goto again; 2000 } 2001 2002 unix_state_unlock(sk); 2003 2004 if (check_creds) { 2005 /* Never glue messages from different writers */ 2006 if ((UNIXCB(skb).pid != siocb->scm->pid) || 2007 (UNIXCB(skb).cred != siocb->scm->cred)) 2008 break; 2009 } else { 2010 /* Copy credentials */ 2011 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred); 2012 check_creds = 1; 2013 } 2014 2015 /* Copy address just once */ 2016 if (sunaddr) { 2017 unix_copy_addr(msg, skb->sk); 2018 sunaddr = NULL; 2019 } 2020 2021 chunk = min_t(unsigned int, skb->len - skip, size); 2022 if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) { 2023 if (copied == 0) 2024 copied = -EFAULT; 2025 break; 2026 } 2027 copied += chunk; 2028 size -= chunk; 2029 2030 /* Mark read part of skb as used */ 2031 if (!(flags & MSG_PEEK)) { 2032 skb_pull(skb, chunk); 2033 2034 sk_peek_offset_bwd(sk, chunk); 2035 2036 if (UNIXCB(skb).fp) 2037 unix_detach_fds(siocb->scm, skb); 2038 2039 if (skb->len) 2040 break; 2041 2042 skb_unlink(skb, &sk->sk_receive_queue); 2043 consume_skb(skb); 2044 2045 if (siocb->scm->fp) 2046 break; 2047 } else { 2048 /* It is questionable, see note in unix_dgram_recvmsg. 2049 */ 2050 if (UNIXCB(skb).fp) 2051 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2052 2053 sk_peek_offset_fwd(sk, chunk); 2054 2055 break; 2056 } 2057 } while (size); 2058 2059 mutex_unlock(&u->readlock); 2060 scm_recv(sock, msg, siocb->scm, flags); 2061out: 2062 return copied ? : err; 2063} 2064 2065static int unix_shutdown(struct socket *sock, int mode) 2066{ 2067 struct sock *sk = sock->sk; 2068 struct sock *other; 2069 2070 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN); 2071 2072 if (!mode) 2073 return 0; 2074 2075 unix_state_lock(sk); 2076 sk->sk_shutdown |= mode; 2077 other = unix_peer(sk); 2078 if (other) 2079 sock_hold(other); 2080 unix_state_unlock(sk); 2081 sk->sk_state_change(sk); 2082 2083 if (other && 2084 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2085 2086 int peer_mode = 0; 2087 2088 if (mode&RCV_SHUTDOWN) 2089 peer_mode |= SEND_SHUTDOWN; 2090 if (mode&SEND_SHUTDOWN) 2091 peer_mode |= RCV_SHUTDOWN; 2092 unix_state_lock(other); 2093 other->sk_shutdown |= peer_mode; 2094 unix_state_unlock(other); 2095 other->sk_state_change(other); 2096 if (peer_mode == SHUTDOWN_MASK) 2097 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2098 else if (peer_mode & RCV_SHUTDOWN) 2099 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2100 } 2101 if (other) 2102 sock_put(other); 2103 2104 return 0; 2105} 2106 2107long unix_inq_len(struct sock *sk) 2108{ 2109 struct sk_buff *skb; 2110 long amount = 0; 2111 2112 if (sk->sk_state == TCP_LISTEN) 2113 return -EINVAL; 2114 2115 spin_lock(&sk->sk_receive_queue.lock); 2116 if (sk->sk_type == SOCK_STREAM || 2117 sk->sk_type == SOCK_SEQPACKET) { 2118 skb_queue_walk(&sk->sk_receive_queue, skb) 2119 amount += skb->len; 2120 } else { 2121 skb = skb_peek(&sk->sk_receive_queue); 2122 if (skb) 2123 amount = skb->len; 2124 } 2125 spin_unlock(&sk->sk_receive_queue.lock); 2126 2127 return amount; 2128} 2129EXPORT_SYMBOL_GPL(unix_inq_len); 2130 2131long unix_outq_len(struct sock *sk) 2132{ 2133 return sk_wmem_alloc_get(sk); 2134} 2135EXPORT_SYMBOL_GPL(unix_outq_len); 2136 2137static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2138{ 2139 struct sock *sk = sock->sk; 2140 long amount = 0; 2141 int err; 2142 2143 switch (cmd) { 2144 case SIOCOUTQ: 2145 amount = unix_outq_len(sk); 2146 err = put_user(amount, (int __user *)arg); 2147 break; 2148 case SIOCINQ: 2149 amount = unix_inq_len(sk); 2150 if (amount < 0) 2151 err = amount; 2152 else 2153 err = put_user(amount, (int __user *)arg); 2154 break; 2155 default: 2156 err = -ENOIOCTLCMD; 2157 break; 2158 } 2159 return err; 2160} 2161 2162static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2163{ 2164 struct sock *sk = sock->sk; 2165 unsigned int mask; 2166 2167 sock_poll_wait(file, sk_sleep(sk), wait); 2168 mask = 0; 2169 2170 /* exceptional events? */ 2171 if (sk->sk_err) 2172 mask |= POLLERR; 2173 if (sk->sk_shutdown == SHUTDOWN_MASK) 2174 mask |= POLLHUP; 2175 if (sk->sk_shutdown & RCV_SHUTDOWN) 2176 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2177 2178 /* readable? */ 2179 if (!skb_queue_empty(&sk->sk_receive_queue)) 2180 mask |= POLLIN | POLLRDNORM; 2181 2182 /* Connection-based need to check for termination and startup */ 2183 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2184 sk->sk_state == TCP_CLOSE) 2185 mask |= POLLHUP; 2186 2187 /* 2188 * we set writable also when the other side has shut down the 2189 * connection. This prevents stuck sockets. 2190 */ 2191 if (unix_writable(sk)) 2192 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2193 2194 return mask; 2195} 2196 2197static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2198 poll_table *wait) 2199{ 2200 struct sock *sk = sock->sk, *other; 2201 unsigned int mask, writable; 2202 2203 sock_poll_wait(file, sk_sleep(sk), wait); 2204 mask = 0; 2205 2206 /* exceptional events? */ 2207 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2208 mask |= POLLERR; 2209 if (sk->sk_shutdown & RCV_SHUTDOWN) 2210 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2211 if (sk->sk_shutdown == SHUTDOWN_MASK) 2212 mask |= POLLHUP; 2213 2214 /* readable? */ 2215 if (!skb_queue_empty(&sk->sk_receive_queue)) 2216 mask |= POLLIN | POLLRDNORM; 2217 2218 /* Connection-based need to check for termination and startup */ 2219 if (sk->sk_type == SOCK_SEQPACKET) { 2220 if (sk->sk_state == TCP_CLOSE) 2221 mask |= POLLHUP; 2222 /* connection hasn't started yet? */ 2223 if (sk->sk_state == TCP_SYN_SENT) 2224 return mask; 2225 } 2226 2227 /* No write status requested, avoid expensive OUT tests. */ 2228 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) 2229 return mask; 2230 2231 writable = unix_writable(sk); 2232 other = unix_peer_get(sk); 2233 if (other) { 2234 if (unix_peer(other) != sk) { 2235 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2236 if (unix_recvq_full(other)) 2237 writable = 0; 2238 } 2239 sock_put(other); 2240 } 2241 2242 if (writable) 2243 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2244 else 2245 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2246 2247 return mask; 2248} 2249 2250#ifdef CONFIG_PROC_FS 2251 2252#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) 2253 2254#define get_bucket(x) ((x) >> BUCKET_SPACE) 2255#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1)) 2256#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) 2257 2258static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) 2259{ 2260 unsigned long offset = get_offset(*pos); 2261 unsigned long bucket = get_bucket(*pos); 2262 struct sock *sk; 2263 unsigned long count = 0; 2264 2265 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) { 2266 if (sock_net(sk) != seq_file_net(seq)) 2267 continue; 2268 if (++count == offset) 2269 break; 2270 } 2271 2272 return sk; 2273} 2274 2275static struct sock *unix_next_socket(struct seq_file *seq, 2276 struct sock *sk, 2277 loff_t *pos) 2278{ 2279 unsigned long bucket; 2280 2281 while (sk > (struct sock *)SEQ_START_TOKEN) { 2282 sk = sk_next(sk); 2283 if (!sk) 2284 goto next_bucket; 2285 if (sock_net(sk) == seq_file_net(seq)) 2286 return sk; 2287 } 2288 2289 do { 2290 sk = unix_from_bucket(seq, pos); 2291 if (sk) 2292 return sk; 2293 2294next_bucket: 2295 bucket = get_bucket(*pos) + 1; 2296 *pos = set_bucket_offset(bucket, 1); 2297 } while (bucket < ARRAY_SIZE(unix_socket_table)); 2298 2299 return NULL; 2300} 2301 2302static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2303 __acquires(unix_table_lock) 2304{ 2305 spin_lock(&unix_table_lock); 2306 2307 if (!*pos) 2308 return SEQ_START_TOKEN; 2309 2310 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table)) 2311 return NULL; 2312 2313 return unix_next_socket(seq, NULL, pos); 2314} 2315 2316static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2317{ 2318 ++*pos; 2319 return unix_next_socket(seq, v, pos); 2320} 2321 2322static void unix_seq_stop(struct seq_file *seq, void *v) 2323 __releases(unix_table_lock) 2324{ 2325 spin_unlock(&unix_table_lock); 2326} 2327 2328static int unix_seq_show(struct seq_file *seq, void *v) 2329{ 2330 2331 if (v == SEQ_START_TOKEN) 2332 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2333 "Inode Path\n"); 2334 else { 2335 struct sock *s = v; 2336 struct unix_sock *u = unix_sk(s); 2337 unix_state_lock(s); 2338 2339 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2340 s, 2341 atomic_read(&s->sk_refcnt), 2342 0, 2343 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2344 s->sk_type, 2345 s->sk_socket ? 2346 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2347 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2348 sock_i_ino(s)); 2349 2350 if (u->addr) { 2351 int i, len; 2352 seq_putc(seq, ' '); 2353 2354 i = 0; 2355 len = u->addr->len - sizeof(short); 2356 if (!UNIX_ABSTRACT(s)) 2357 len--; 2358 else { 2359 seq_putc(seq, '@'); 2360 i++; 2361 } 2362 for ( ; i < len; i++) 2363 seq_putc(seq, u->addr->name->sun_path[i]); 2364 } 2365 unix_state_unlock(s); 2366 seq_putc(seq, '\n'); 2367 } 2368 2369 return 0; 2370} 2371 2372static const struct seq_operations unix_seq_ops = { 2373 .start = unix_seq_start, 2374 .next = unix_seq_next, 2375 .stop = unix_seq_stop, 2376 .show = unix_seq_show, 2377}; 2378 2379static int unix_seq_open(struct inode *inode, struct file *file) 2380{ 2381 return seq_open_net(inode, file, &unix_seq_ops, 2382 sizeof(struct seq_net_private)); 2383} 2384 2385static const struct file_operations unix_seq_fops = { 2386 .owner = THIS_MODULE, 2387 .open = unix_seq_open, 2388 .read = seq_read, 2389 .llseek = seq_lseek, 2390 .release = seq_release_net, 2391}; 2392 2393#endif 2394 2395static const struct net_proto_family unix_family_ops = { 2396 .family = PF_UNIX, 2397 .create = unix_create, 2398 .owner = THIS_MODULE, 2399}; 2400 2401 2402static int __net_init unix_net_init(struct net *net) 2403{ 2404 int error = -ENOMEM; 2405 2406 net->unx.sysctl_max_dgram_qlen = 10; 2407 if (unix_sysctl_register(net)) 2408 goto out; 2409 2410#ifdef CONFIG_PROC_FS 2411 if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops)) { 2412 unix_sysctl_unregister(net); 2413 goto out; 2414 } 2415#endif 2416 error = 0; 2417out: 2418 return error; 2419} 2420 2421static void __net_exit unix_net_exit(struct net *net) 2422{ 2423 unix_sysctl_unregister(net); 2424 proc_net_remove(net, "unix"); 2425} 2426 2427static struct pernet_operations unix_net_ops = { 2428 .init = unix_net_init, 2429 .exit = unix_net_exit, 2430}; 2431 2432static int __init af_unix_init(void) 2433{ 2434 int rc = -1; 2435 struct sk_buff *dummy_skb; 2436 2437 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb)); 2438 2439 rc = proto_register(&unix_proto, 1); 2440 if (rc != 0) { 2441 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2442 __func__); 2443 goto out; 2444 } 2445 2446 sock_register(&unix_family_ops); 2447 register_pernet_subsys(&unix_net_ops); 2448out: 2449 return rc; 2450} 2451 2452static void __exit af_unix_exit(void) 2453{ 2454 sock_unregister(PF_UNIX); 2455 proto_unregister(&unix_proto); 2456 unregister_pernet_subsys(&unix_net_ops); 2457} 2458 2459/* Earlier than device_initcall() so that other drivers invoking 2460 request_module() don't end up in a loop when modprobe tries 2461 to use a UNIX socket. But later than subsys_initcall() because 2462 we depend on stuff initialised there */ 2463fs_initcall(af_unix_init); 2464module_exit(af_unix_exit); 2465 2466MODULE_LICENSE("GPL"); 2467MODULE_ALIAS_NETPROTO(PF_UNIX); 2468