af_unix.c revision de1443916791d75fdd26becb116898277bb0273f
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 84 85#include <linux/module.h> 86#include <linux/kernel.h> 87#include <linux/signal.h> 88#include <linux/sched.h> 89#include <linux/errno.h> 90#include <linux/string.h> 91#include <linux/stat.h> 92#include <linux/dcache.h> 93#include <linux/namei.h> 94#include <linux/socket.h> 95#include <linux/un.h> 96#include <linux/fcntl.h> 97#include <linux/termios.h> 98#include <linux/sockios.h> 99#include <linux/net.h> 100#include <linux/in.h> 101#include <linux/fs.h> 102#include <linux/slab.h> 103#include <asm/uaccess.h> 104#include <linux/skbuff.h> 105#include <linux/netdevice.h> 106#include <net/net_namespace.h> 107#include <net/sock.h> 108#include <net/tcp_states.h> 109#include <net/af_unix.h> 110#include <linux/proc_fs.h> 111#include <linux/seq_file.h> 112#include <net/scm.h> 113#include <linux/init.h> 114#include <linux/poll.h> 115#include <linux/rtnetlink.h> 116#include <linux/mount.h> 117#include <net/checksum.h> 118#include <linux/security.h> 119#include <linux/freezer.h> 120 121struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE]; 122EXPORT_SYMBOL_GPL(unix_socket_table); 123DEFINE_SPINLOCK(unix_table_lock); 124EXPORT_SYMBOL_GPL(unix_table_lock); 125static atomic_long_t unix_nr_socks; 126 127 128static struct hlist_head *unix_sockets_unbound(void *addr) 129{ 130 unsigned long hash = (unsigned long)addr; 131 132 hash ^= hash >> 16; 133 hash ^= hash >> 8; 134 hash %= UNIX_HASH_SIZE; 135 return &unix_socket_table[UNIX_HASH_SIZE + hash]; 136} 137 138#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash < UNIX_HASH_SIZE) 139 140#ifdef CONFIG_SECURITY_NETWORK 141static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 142{ 143 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 144} 145 146static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 147{ 148 scm->secid = *UNIXSID(skb); 149} 150#else 151static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 152{ } 153 154static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 155{ } 156#endif /* CONFIG_SECURITY_NETWORK */ 157 158/* 159 * SMP locking strategy: 160 * hash table is protected with spinlock unix_table_lock 161 * each socket state is protected by separate spin lock. 162 */ 163 164static inline unsigned int unix_hash_fold(__wsum n) 165{ 166 unsigned int hash = (__force unsigned int)csum_fold(n); 167 168 hash ^= hash>>8; 169 return hash&(UNIX_HASH_SIZE-1); 170} 171 172#define unix_peer(sk) (unix_sk(sk)->peer) 173 174static inline int unix_our_peer(struct sock *sk, struct sock *osk) 175{ 176 return unix_peer(osk) == sk; 177} 178 179static inline int unix_may_send(struct sock *sk, struct sock *osk) 180{ 181 return unix_peer(osk) == NULL || unix_our_peer(sk, osk); 182} 183 184static inline int unix_recvq_full(struct sock const *sk) 185{ 186 return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; 187} 188 189struct sock *unix_peer_get(struct sock *s) 190{ 191 struct sock *peer; 192 193 unix_state_lock(s); 194 peer = unix_peer(s); 195 if (peer) 196 sock_hold(peer); 197 unix_state_unlock(s); 198 return peer; 199} 200EXPORT_SYMBOL_GPL(unix_peer_get); 201 202static inline void unix_release_addr(struct unix_address *addr) 203{ 204 if (atomic_dec_and_test(&addr->refcnt)) 205 kfree(addr); 206} 207 208/* 209 * Check unix socket name: 210 * - should be not zero length. 211 * - if started by not zero, should be NULL terminated (FS object) 212 * - if started by zero, it is abstract name. 213 */ 214 215static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp) 216{ 217 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 218 return -EINVAL; 219 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 220 return -EINVAL; 221 if (sunaddr->sun_path[0]) { 222 /* 223 * This may look like an off by one error but it is a bit more 224 * subtle. 108 is the longest valid AF_UNIX path for a binding. 225 * sun_path[108] doesn't as such exist. However in kernel space 226 * we are guaranteed that it is a valid memory location in our 227 * kernel address buffer. 228 */ 229 ((char *)sunaddr)[len] = 0; 230 len = strlen(sunaddr->sun_path)+1+sizeof(short); 231 return len; 232 } 233 234 *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0)); 235 return len; 236} 237 238static void __unix_remove_socket(struct sock *sk) 239{ 240 sk_del_node_init(sk); 241} 242 243static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 244{ 245 WARN_ON(!sk_unhashed(sk)); 246 sk_add_node(sk, list); 247} 248 249static inline void unix_remove_socket(struct sock *sk) 250{ 251 spin_lock(&unix_table_lock); 252 __unix_remove_socket(sk); 253 spin_unlock(&unix_table_lock); 254} 255 256static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 257{ 258 spin_lock(&unix_table_lock); 259 __unix_insert_socket(list, sk); 260 spin_unlock(&unix_table_lock); 261} 262 263static struct sock *__unix_find_socket_byname(struct net *net, 264 struct sockaddr_un *sunname, 265 int len, int type, unsigned int hash) 266{ 267 struct sock *s; 268 269 sk_for_each(s, &unix_socket_table[hash ^ type]) { 270 struct unix_sock *u = unix_sk(s); 271 272 if (!net_eq(sock_net(s), net)) 273 continue; 274 275 if (u->addr->len == len && 276 !memcmp(u->addr->name, sunname, len)) 277 goto found; 278 } 279 s = NULL; 280found: 281 return s; 282} 283 284static inline struct sock *unix_find_socket_byname(struct net *net, 285 struct sockaddr_un *sunname, 286 int len, int type, 287 unsigned int hash) 288{ 289 struct sock *s; 290 291 spin_lock(&unix_table_lock); 292 s = __unix_find_socket_byname(net, sunname, len, type, hash); 293 if (s) 294 sock_hold(s); 295 spin_unlock(&unix_table_lock); 296 return s; 297} 298 299static struct sock *unix_find_socket_byinode(struct inode *i) 300{ 301 struct sock *s; 302 303 spin_lock(&unix_table_lock); 304 sk_for_each(s, 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 pr_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 pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk, 383 atomic_long_read(&unix_nr_socks)); 384#endif 385} 386 387static void 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 458static void init_peercred(struct sock *sk) 459{ 460 put_pid(sk->sk_peer_pid); 461 if (sk->sk_peer_cred) 462 put_cred(sk->sk_peer_cred); 463 sk->sk_peer_pid = get_pid(task_tgid(current)); 464 sk->sk_peer_cred = get_current_cred(); 465} 466 467static void copy_peercred(struct sock *sk, struct sock *peersk) 468{ 469 put_pid(sk->sk_peer_pid); 470 if (sk->sk_peer_cred) 471 put_cred(sk->sk_peer_cred); 472 sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); 473 sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); 474} 475 476static int unix_listen(struct socket *sock, int backlog) 477{ 478 int err; 479 struct sock *sk = sock->sk; 480 struct unix_sock *u = unix_sk(sk); 481 struct pid *old_pid = NULL; 482 483 err = -EOPNOTSUPP; 484 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 485 goto out; /* Only stream/seqpacket sockets accept */ 486 err = -EINVAL; 487 if (!u->addr) 488 goto out; /* No listens on an unbound socket */ 489 unix_state_lock(sk); 490 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 491 goto out_unlock; 492 if (backlog > sk->sk_max_ack_backlog) 493 wake_up_interruptible_all(&u->peer_wait); 494 sk->sk_max_ack_backlog = backlog; 495 sk->sk_state = TCP_LISTEN; 496 /* set credentials so connect can copy them */ 497 init_peercred(sk); 498 err = 0; 499 500out_unlock: 501 unix_state_unlock(sk); 502 put_pid(old_pid); 503out: 504 return err; 505} 506 507static int unix_release(struct socket *); 508static int unix_bind(struct socket *, struct sockaddr *, int); 509static int unix_stream_connect(struct socket *, struct sockaddr *, 510 int addr_len, int flags); 511static int unix_socketpair(struct socket *, struct socket *); 512static int unix_accept(struct socket *, struct socket *, int); 513static int unix_getname(struct socket *, struct sockaddr *, int *, int); 514static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 515static unsigned int unix_dgram_poll(struct file *, struct socket *, 516 poll_table *); 517static int unix_ioctl(struct socket *, unsigned int, unsigned long); 518static int unix_shutdown(struct socket *, int); 519static int unix_stream_sendmsg(struct kiocb *, struct socket *, 520 struct msghdr *, size_t); 521static int unix_stream_recvmsg(struct kiocb *, struct socket *, 522 struct msghdr *, size_t, int); 523static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 524 struct msghdr *, size_t); 525static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 526 struct msghdr *, size_t, int); 527static int unix_dgram_connect(struct socket *, struct sockaddr *, 528 int, int); 529static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 530 struct msghdr *, size_t); 531static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *, 532 struct msghdr *, size_t, int); 533 534static int unix_set_peek_off(struct sock *sk, int val) 535{ 536 struct unix_sock *u = unix_sk(sk); 537 538 if (mutex_lock_interruptible(&u->readlock)) 539 return -EINTR; 540 541 sk->sk_peek_off = val; 542 mutex_unlock(&u->readlock); 543 544 return 0; 545} 546 547 548static const struct proto_ops unix_stream_ops = { 549 .family = PF_UNIX, 550 .owner = THIS_MODULE, 551 .release = unix_release, 552 .bind = unix_bind, 553 .connect = unix_stream_connect, 554 .socketpair = unix_socketpair, 555 .accept = unix_accept, 556 .getname = unix_getname, 557 .poll = unix_poll, 558 .ioctl = unix_ioctl, 559 .listen = unix_listen, 560 .shutdown = unix_shutdown, 561 .setsockopt = sock_no_setsockopt, 562 .getsockopt = sock_no_getsockopt, 563 .sendmsg = unix_stream_sendmsg, 564 .recvmsg = unix_stream_recvmsg, 565 .mmap = sock_no_mmap, 566 .sendpage = sock_no_sendpage, 567 .set_peek_off = unix_set_peek_off, 568}; 569 570static const struct proto_ops unix_dgram_ops = { 571 .family = PF_UNIX, 572 .owner = THIS_MODULE, 573 .release = unix_release, 574 .bind = unix_bind, 575 .connect = unix_dgram_connect, 576 .socketpair = unix_socketpair, 577 .accept = sock_no_accept, 578 .getname = unix_getname, 579 .poll = unix_dgram_poll, 580 .ioctl = unix_ioctl, 581 .listen = sock_no_listen, 582 .shutdown = unix_shutdown, 583 .setsockopt = sock_no_setsockopt, 584 .getsockopt = sock_no_getsockopt, 585 .sendmsg = unix_dgram_sendmsg, 586 .recvmsg = unix_dgram_recvmsg, 587 .mmap = sock_no_mmap, 588 .sendpage = sock_no_sendpage, 589 .set_peek_off = unix_set_peek_off, 590}; 591 592static const struct proto_ops unix_seqpacket_ops = { 593 .family = PF_UNIX, 594 .owner = THIS_MODULE, 595 .release = unix_release, 596 .bind = unix_bind, 597 .connect = unix_stream_connect, 598 .socketpair = unix_socketpair, 599 .accept = unix_accept, 600 .getname = unix_getname, 601 .poll = unix_dgram_poll, 602 .ioctl = unix_ioctl, 603 .listen = unix_listen, 604 .shutdown = unix_shutdown, 605 .setsockopt = sock_no_setsockopt, 606 .getsockopt = sock_no_getsockopt, 607 .sendmsg = unix_seqpacket_sendmsg, 608 .recvmsg = unix_seqpacket_recvmsg, 609 .mmap = sock_no_mmap, 610 .sendpage = sock_no_sendpage, 611 .set_peek_off = unix_set_peek_off, 612}; 613 614static struct proto unix_proto = { 615 .name = "UNIX", 616 .owner = THIS_MODULE, 617 .obj_size = sizeof(struct unix_sock), 618}; 619 620/* 621 * AF_UNIX sockets do not interact with hardware, hence they 622 * dont trigger interrupts - so it's safe for them to have 623 * bh-unsafe locking for their sk_receive_queue.lock. Split off 624 * this special lock-class by reinitializing the spinlock key: 625 */ 626static struct lock_class_key af_unix_sk_receive_queue_lock_key; 627 628static struct sock *unix_create1(struct net *net, struct socket *sock) 629{ 630 struct sock *sk = NULL; 631 struct unix_sock *u; 632 633 atomic_long_inc(&unix_nr_socks); 634 if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) 635 goto out; 636 637 sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto); 638 if (!sk) 639 goto out; 640 641 sock_init_data(sock, sk); 642 lockdep_set_class(&sk->sk_receive_queue.lock, 643 &af_unix_sk_receive_queue_lock_key); 644 645 sk->sk_write_space = unix_write_space; 646 sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; 647 sk->sk_destruct = unix_sock_destructor; 648 u = unix_sk(sk); 649 u->path.dentry = NULL; 650 u->path.mnt = NULL; 651 spin_lock_init(&u->lock); 652 atomic_long_set(&u->inflight, 0); 653 INIT_LIST_HEAD(&u->link); 654 mutex_init(&u->readlock); /* single task reading lock */ 655 init_waitqueue_head(&u->peer_wait); 656 unix_insert_socket(unix_sockets_unbound(sk), sk); 657out: 658 if (sk == NULL) 659 atomic_long_dec(&unix_nr_socks); 660 else { 661 local_bh_disable(); 662 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 663 local_bh_enable(); 664 } 665 return sk; 666} 667 668static int unix_create(struct net *net, struct socket *sock, int protocol, 669 int kern) 670{ 671 if (protocol && protocol != PF_UNIX) 672 return -EPROTONOSUPPORT; 673 674 sock->state = SS_UNCONNECTED; 675 676 switch (sock->type) { 677 case SOCK_STREAM: 678 sock->ops = &unix_stream_ops; 679 break; 680 /* 681 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 682 * nothing uses it. 683 */ 684 case SOCK_RAW: 685 sock->type = SOCK_DGRAM; 686 case SOCK_DGRAM: 687 sock->ops = &unix_dgram_ops; 688 break; 689 case SOCK_SEQPACKET: 690 sock->ops = &unix_seqpacket_ops; 691 break; 692 default: 693 return -ESOCKTNOSUPPORT; 694 } 695 696 return unix_create1(net, sock) ? 0 : -ENOMEM; 697} 698 699static int unix_release(struct socket *sock) 700{ 701 struct sock *sk = sock->sk; 702 703 if (!sk) 704 return 0; 705 706 unix_release_sock(sk, 0); 707 sock->sk = NULL; 708 709 return 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 err = mutex_lock_interruptible(&u->readlock); 723 if (err) 724 return err; 725 726 err = 0; 727 if (u->addr) 728 goto out; 729 730 err = -ENOMEM; 731 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 732 if (!addr) 733 goto out; 734 735 addr->name->sun_family = AF_UNIX; 736 atomic_set(&addr->refcnt, 1); 737 738retry: 739 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 740 addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0)); 741 742 spin_lock(&unix_table_lock); 743 ordernum = (ordernum+1)&0xFFFFF; 744 745 if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type, 746 addr->hash)) { 747 spin_unlock(&unix_table_lock); 748 /* 749 * __unix_find_socket_byname() may take long time if many names 750 * are already in use. 751 */ 752 cond_resched(); 753 /* Give up if all names seems to be in use. */ 754 if (retries++ == 0xFFFFF) { 755 err = -ENOSPC; 756 kfree(addr); 757 goto out; 758 } 759 goto retry; 760 } 761 addr->hash ^= sk->sk_type; 762 763 __unix_remove_socket(sk); 764 u->addr = addr; 765 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 766 spin_unlock(&unix_table_lock); 767 err = 0; 768 769out: mutex_unlock(&u->readlock); 770 return err; 771} 772 773static struct sock *unix_find_other(struct net *net, 774 struct sockaddr_un *sunname, int len, 775 int type, unsigned int hash, int *error) 776{ 777 struct sock *u; 778 struct path path; 779 int err = 0; 780 781 if (sunname->sun_path[0]) { 782 struct inode *inode; 783 err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); 784 if (err) 785 goto fail; 786 inode = path.dentry->d_inode; 787 err = inode_permission(inode, MAY_WRITE); 788 if (err) 789 goto put_fail; 790 791 err = -ECONNREFUSED; 792 if (!S_ISSOCK(inode->i_mode)) 793 goto put_fail; 794 u = unix_find_socket_byinode(inode); 795 if (!u) 796 goto put_fail; 797 798 if (u->sk_type == type) 799 touch_atime(&path); 800 801 path_put(&path); 802 803 err = -EPROTOTYPE; 804 if (u->sk_type != type) { 805 sock_put(u); 806 goto fail; 807 } 808 } else { 809 err = -ECONNREFUSED; 810 u = unix_find_socket_byname(net, sunname, len, type, hash); 811 if (u) { 812 struct dentry *dentry; 813 dentry = unix_sk(u)->path.dentry; 814 if (dentry) 815 touch_atime(&unix_sk(u)->path); 816 } else 817 goto fail; 818 } 819 return u; 820 821put_fail: 822 path_put(&path); 823fail: 824 *error = err; 825 return NULL; 826} 827 828static int unix_mknod(const char *sun_path, umode_t mode, struct path *res) 829{ 830 struct dentry *dentry; 831 struct path path; 832 int err = 0; 833 /* 834 * Get the parent directory, calculate the hash for last 835 * component. 836 */ 837 dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0); 838 err = PTR_ERR(dentry); 839 if (IS_ERR(dentry)) 840 return err; 841 842 /* 843 * All right, let's create it. 844 */ 845 err = security_path_mknod(&path, dentry, mode, 0); 846 if (!err) { 847 err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0); 848 if (!err) { 849 res->mnt = mntget(path.mnt); 850 res->dentry = dget(dentry); 851 } 852 } 853 done_path_create(&path, dentry); 854 return err; 855} 856 857static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 858{ 859 struct sock *sk = sock->sk; 860 struct net *net = sock_net(sk); 861 struct unix_sock *u = unix_sk(sk); 862 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 863 char *sun_path = sunaddr->sun_path; 864 int err; 865 unsigned int hash; 866 struct unix_address *addr; 867 struct hlist_head *list; 868 869 err = -EINVAL; 870 if (sunaddr->sun_family != AF_UNIX) 871 goto out; 872 873 if (addr_len == sizeof(short)) { 874 err = unix_autobind(sock); 875 goto out; 876 } 877 878 err = unix_mkname(sunaddr, addr_len, &hash); 879 if (err < 0) 880 goto out; 881 addr_len = err; 882 883 err = mutex_lock_interruptible(&u->readlock); 884 if (err) 885 goto out; 886 887 err = -EINVAL; 888 if (u->addr) 889 goto out_up; 890 891 err = -ENOMEM; 892 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 893 if (!addr) 894 goto out_up; 895 896 memcpy(addr->name, sunaddr, addr_len); 897 addr->len = addr_len; 898 addr->hash = hash ^ sk->sk_type; 899 atomic_set(&addr->refcnt, 1); 900 901 if (sun_path[0]) { 902 struct path path; 903 umode_t mode = S_IFSOCK | 904 (SOCK_INODE(sock)->i_mode & ~current_umask()); 905 err = unix_mknod(sun_path, mode, &path); 906 if (err) { 907 if (err == -EEXIST) 908 err = -EADDRINUSE; 909 unix_release_addr(addr); 910 goto out_up; 911 } 912 addr->hash = UNIX_HASH_SIZE; 913 hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1); 914 spin_lock(&unix_table_lock); 915 u->path = path; 916 list = &unix_socket_table[hash]; 917 } else { 918 spin_lock(&unix_table_lock); 919 err = -EADDRINUSE; 920 if (__unix_find_socket_byname(net, sunaddr, addr_len, 921 sk->sk_type, hash)) { 922 unix_release_addr(addr); 923 goto out_unlock; 924 } 925 926 list = &unix_socket_table[addr->hash]; 927 } 928 929 err = 0; 930 __unix_remove_socket(sk); 931 u->addr = addr; 932 __unix_insert_socket(list, sk); 933 934out_unlock: 935 spin_unlock(&unix_table_lock); 936out_up: 937 mutex_unlock(&u->readlock); 938out: 939 return err; 940} 941 942static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) 943{ 944 if (unlikely(sk1 == sk2) || !sk2) { 945 unix_state_lock(sk1); 946 return; 947 } 948 if (sk1 < sk2) { 949 unix_state_lock(sk1); 950 unix_state_lock_nested(sk2); 951 } else { 952 unix_state_lock(sk2); 953 unix_state_lock_nested(sk1); 954 } 955} 956 957static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) 958{ 959 if (unlikely(sk1 == sk2) || !sk2) { 960 unix_state_unlock(sk1); 961 return; 962 } 963 unix_state_unlock(sk1); 964 unix_state_unlock(sk2); 965} 966 967static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 968 int alen, int flags) 969{ 970 struct sock *sk = sock->sk; 971 struct net *net = sock_net(sk); 972 struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; 973 struct sock *other; 974 unsigned int hash; 975 int err; 976 977 if (addr->sa_family != AF_UNSPEC) { 978 err = unix_mkname(sunaddr, alen, &hash); 979 if (err < 0) 980 goto out; 981 alen = err; 982 983 if (test_bit(SOCK_PASSCRED, &sock->flags) && 984 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 985 goto out; 986 987restart: 988 other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); 989 if (!other) 990 goto out; 991 992 unix_state_double_lock(sk, other); 993 994 /* Apparently VFS overslept socket death. Retry. */ 995 if (sock_flag(other, SOCK_DEAD)) { 996 unix_state_double_unlock(sk, other); 997 sock_put(other); 998 goto restart; 999 } 1000 1001 err = -EPERM; 1002 if (!unix_may_send(sk, other)) 1003 goto out_unlock; 1004 1005 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1006 if (err) 1007 goto out_unlock; 1008 1009 } else { 1010 /* 1011 * 1003.1g breaking connected state with AF_UNSPEC 1012 */ 1013 other = NULL; 1014 unix_state_double_lock(sk, other); 1015 } 1016 1017 /* 1018 * If it was connected, reconnect. 1019 */ 1020 if (unix_peer(sk)) { 1021 struct sock *old_peer = unix_peer(sk); 1022 unix_peer(sk) = other; 1023 unix_state_double_unlock(sk, other); 1024 1025 if (other != old_peer) 1026 unix_dgram_disconnected(sk, old_peer); 1027 sock_put(old_peer); 1028 } else { 1029 unix_peer(sk) = other; 1030 unix_state_double_unlock(sk, other); 1031 } 1032 return 0; 1033 1034out_unlock: 1035 unix_state_double_unlock(sk, other); 1036 sock_put(other); 1037out: 1038 return err; 1039} 1040 1041static long unix_wait_for_peer(struct sock *other, long timeo) 1042{ 1043 struct unix_sock *u = unix_sk(other); 1044 int sched; 1045 DEFINE_WAIT(wait); 1046 1047 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 1048 1049 sched = !sock_flag(other, SOCK_DEAD) && 1050 !(other->sk_shutdown & RCV_SHUTDOWN) && 1051 unix_recvq_full(other); 1052 1053 unix_state_unlock(other); 1054 1055 if (sched) 1056 timeo = schedule_timeout(timeo); 1057 1058 finish_wait(&u->peer_wait, &wait); 1059 return timeo; 1060} 1061 1062static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 1063 int addr_len, int flags) 1064{ 1065 struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; 1066 struct sock *sk = sock->sk; 1067 struct net *net = sock_net(sk); 1068 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 1069 struct sock *newsk = NULL; 1070 struct sock *other = NULL; 1071 struct sk_buff *skb = NULL; 1072 unsigned int hash; 1073 int st; 1074 int err; 1075 long timeo; 1076 1077 err = unix_mkname(sunaddr, addr_len, &hash); 1078 if (err < 0) 1079 goto out; 1080 addr_len = err; 1081 1082 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr && 1083 (err = unix_autobind(sock)) != 0) 1084 goto out; 1085 1086 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 1087 1088 /* First of all allocate resources. 1089 If we will make it after state is locked, 1090 we will have to recheck all again in any case. 1091 */ 1092 1093 err = -ENOMEM; 1094 1095 /* create new sock for complete connection */ 1096 newsk = unix_create1(sock_net(sk), NULL); 1097 if (newsk == NULL) 1098 goto out; 1099 1100 /* Allocate skb for sending to listening sock */ 1101 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 1102 if (skb == NULL) 1103 goto out; 1104 1105restart: 1106 /* Find listening sock. */ 1107 other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); 1108 if (!other) 1109 goto out; 1110 1111 /* Latch state of peer */ 1112 unix_state_lock(other); 1113 1114 /* Apparently VFS overslept socket death. Retry. */ 1115 if (sock_flag(other, SOCK_DEAD)) { 1116 unix_state_unlock(other); 1117 sock_put(other); 1118 goto restart; 1119 } 1120 1121 err = -ECONNREFUSED; 1122 if (other->sk_state != TCP_LISTEN) 1123 goto out_unlock; 1124 if (other->sk_shutdown & RCV_SHUTDOWN) 1125 goto out_unlock; 1126 1127 if (unix_recvq_full(other)) { 1128 err = -EAGAIN; 1129 if (!timeo) 1130 goto out_unlock; 1131 1132 timeo = unix_wait_for_peer(other, timeo); 1133 1134 err = sock_intr_errno(timeo); 1135 if (signal_pending(current)) 1136 goto out; 1137 sock_put(other); 1138 goto restart; 1139 } 1140 1141 /* Latch our state. 1142 1143 It is tricky place. We need to grab our state lock and cannot 1144 drop lock on peer. It is dangerous because deadlock is 1145 possible. Connect to self case and simultaneous 1146 attempt to connect are eliminated by checking socket 1147 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1148 check this before attempt to grab lock. 1149 1150 Well, and we have to recheck the state after socket locked. 1151 */ 1152 st = sk->sk_state; 1153 1154 switch (st) { 1155 case TCP_CLOSE: 1156 /* This is ok... continue with connect */ 1157 break; 1158 case TCP_ESTABLISHED: 1159 /* Socket is already connected */ 1160 err = -EISCONN; 1161 goto out_unlock; 1162 default: 1163 err = -EINVAL; 1164 goto out_unlock; 1165 } 1166 1167 unix_state_lock_nested(sk); 1168 1169 if (sk->sk_state != st) { 1170 unix_state_unlock(sk); 1171 unix_state_unlock(other); 1172 sock_put(other); 1173 goto restart; 1174 } 1175 1176 err = security_unix_stream_connect(sk, other, newsk); 1177 if (err) { 1178 unix_state_unlock(sk); 1179 goto out_unlock; 1180 } 1181 1182 /* The way is open! Fastly set all the necessary fields... */ 1183 1184 sock_hold(sk); 1185 unix_peer(newsk) = sk; 1186 newsk->sk_state = TCP_ESTABLISHED; 1187 newsk->sk_type = sk->sk_type; 1188 init_peercred(newsk); 1189 newu = unix_sk(newsk); 1190 RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); 1191 otheru = unix_sk(other); 1192 1193 /* copy address information from listening to new sock*/ 1194 if (otheru->addr) { 1195 atomic_inc(&otheru->addr->refcnt); 1196 newu->addr = otheru->addr; 1197 } 1198 if (otheru->path.dentry) { 1199 path_get(&otheru->path); 1200 newu->path = otheru->path; 1201 } 1202 1203 /* Set credentials */ 1204 copy_peercred(sk, other); 1205 1206 sock->state = SS_CONNECTED; 1207 sk->sk_state = TCP_ESTABLISHED; 1208 sock_hold(newsk); 1209 1210 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1211 unix_peer(sk) = newsk; 1212 1213 unix_state_unlock(sk); 1214 1215 /* take ten and and send info to listening sock */ 1216 spin_lock(&other->sk_receive_queue.lock); 1217 __skb_queue_tail(&other->sk_receive_queue, skb); 1218 spin_unlock(&other->sk_receive_queue.lock); 1219 unix_state_unlock(other); 1220 other->sk_data_ready(other, 0); 1221 sock_put(other); 1222 return 0; 1223 1224out_unlock: 1225 if (other) 1226 unix_state_unlock(other); 1227 1228out: 1229 kfree_skb(skb); 1230 if (newsk) 1231 unix_release_sock(newsk, 0); 1232 if (other) 1233 sock_put(other); 1234 return err; 1235} 1236 1237static int unix_socketpair(struct socket *socka, struct socket *sockb) 1238{ 1239 struct sock *ska = socka->sk, *skb = sockb->sk; 1240 1241 /* Join our sockets back to back */ 1242 sock_hold(ska); 1243 sock_hold(skb); 1244 unix_peer(ska) = skb; 1245 unix_peer(skb) = ska; 1246 init_peercred(ska); 1247 init_peercred(skb); 1248 1249 if (ska->sk_type != SOCK_DGRAM) { 1250 ska->sk_state = TCP_ESTABLISHED; 1251 skb->sk_state = TCP_ESTABLISHED; 1252 socka->state = SS_CONNECTED; 1253 sockb->state = SS_CONNECTED; 1254 } 1255 return 0; 1256} 1257 1258static void unix_sock_inherit_flags(const struct socket *old, 1259 struct socket *new) 1260{ 1261 if (test_bit(SOCK_PASSCRED, &old->flags)) 1262 set_bit(SOCK_PASSCRED, &new->flags); 1263 if (test_bit(SOCK_PASSSEC, &old->flags)) 1264 set_bit(SOCK_PASSSEC, &new->flags); 1265} 1266 1267static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1268{ 1269 struct sock *sk = sock->sk; 1270 struct sock *tsk; 1271 struct sk_buff *skb; 1272 int err; 1273 1274 err = -EOPNOTSUPP; 1275 if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) 1276 goto out; 1277 1278 err = -EINVAL; 1279 if (sk->sk_state != TCP_LISTEN) 1280 goto out; 1281 1282 /* If socket state is TCP_LISTEN it cannot change (for now...), 1283 * so that no locks are necessary. 1284 */ 1285 1286 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1287 if (!skb) { 1288 /* This means receive shutdown. */ 1289 if (err == 0) 1290 err = -EINVAL; 1291 goto out; 1292 } 1293 1294 tsk = skb->sk; 1295 skb_free_datagram(sk, skb); 1296 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1297 1298 /* attach accepted sock to socket */ 1299 unix_state_lock(tsk); 1300 newsock->state = SS_CONNECTED; 1301 unix_sock_inherit_flags(sock, newsock); 1302 sock_graft(tsk, newsock); 1303 unix_state_unlock(tsk); 1304 return 0; 1305 1306out: 1307 return err; 1308} 1309 1310 1311static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1312{ 1313 struct sock *sk = sock->sk; 1314 struct unix_sock *u; 1315 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); 1316 int err = 0; 1317 1318 if (peer) { 1319 sk = unix_peer_get(sk); 1320 1321 err = -ENOTCONN; 1322 if (!sk) 1323 goto out; 1324 err = 0; 1325 } else { 1326 sock_hold(sk); 1327 } 1328 1329 u = unix_sk(sk); 1330 unix_state_lock(sk); 1331 if (!u->addr) { 1332 sunaddr->sun_family = AF_UNIX; 1333 sunaddr->sun_path[0] = 0; 1334 *uaddr_len = sizeof(short); 1335 } else { 1336 struct unix_address *addr = u->addr; 1337 1338 *uaddr_len = addr->len; 1339 memcpy(sunaddr, addr->name, *uaddr_len); 1340 } 1341 unix_state_unlock(sk); 1342 sock_put(sk); 1343out: 1344 return err; 1345} 1346 1347static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1348{ 1349 int i; 1350 1351 scm->fp = UNIXCB(skb).fp; 1352 UNIXCB(skb).fp = NULL; 1353 1354 for (i = scm->fp->count-1; i >= 0; i--) 1355 unix_notinflight(scm->fp->fp[i]); 1356} 1357 1358static void unix_destruct_scm(struct sk_buff *skb) 1359{ 1360 struct scm_cookie scm; 1361 memset(&scm, 0, sizeof(scm)); 1362 scm.pid = UNIXCB(skb).pid; 1363 if (UNIXCB(skb).fp) 1364 unix_detach_fds(&scm, skb); 1365 1366 /* Alas, it calls VFS */ 1367 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1368 scm_destroy(&scm); 1369 sock_wfree(skb); 1370} 1371 1372#define MAX_RECURSION_LEVEL 4 1373 1374static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1375{ 1376 int i; 1377 unsigned char max_level = 0; 1378 int unix_sock_count = 0; 1379 1380 for (i = scm->fp->count - 1; i >= 0; i--) { 1381 struct sock *sk = unix_get_socket(scm->fp->fp[i]); 1382 1383 if (sk) { 1384 unix_sock_count++; 1385 max_level = max(max_level, 1386 unix_sk(sk)->recursion_level); 1387 } 1388 } 1389 if (unlikely(max_level > MAX_RECURSION_LEVEL)) 1390 return -ETOOMANYREFS; 1391 1392 /* 1393 * Need to duplicate file references for the sake of garbage 1394 * collection. Otherwise a socket in the fps might become a 1395 * candidate for GC while the skb is not yet queued. 1396 */ 1397 UNIXCB(skb).fp = scm_fp_dup(scm->fp); 1398 if (!UNIXCB(skb).fp) 1399 return -ENOMEM; 1400 1401 if (unix_sock_count) { 1402 for (i = scm->fp->count - 1; i >= 0; i--) 1403 unix_inflight(scm->fp->fp[i]); 1404 } 1405 return max_level; 1406} 1407 1408static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) 1409{ 1410 int err = 0; 1411 1412 UNIXCB(skb).pid = get_pid(scm->pid); 1413 UNIXCB(skb).uid = scm->creds.uid; 1414 UNIXCB(skb).gid = scm->creds.gid; 1415 UNIXCB(skb).fp = NULL; 1416 if (scm->fp && send_fds) 1417 err = unix_attach_fds(scm, skb); 1418 1419 skb->destructor = unix_destruct_scm; 1420 return err; 1421} 1422 1423/* 1424 * Some apps rely on write() giving SCM_CREDENTIALS 1425 * We include credentials if source or destination socket 1426 * asserted SOCK_PASSCRED. 1427 */ 1428static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, 1429 const struct sock *other) 1430{ 1431 if (UNIXCB(skb).pid) 1432 return; 1433 if (test_bit(SOCK_PASSCRED, &sock->flags) || 1434 !other->sk_socket || 1435 test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { 1436 UNIXCB(skb).pid = get_pid(task_tgid(current)); 1437 current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); 1438 } 1439} 1440 1441/* 1442 * Send AF_UNIX data. 1443 */ 1444 1445static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1446 struct msghdr *msg, size_t len) 1447{ 1448 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1449 struct sock *sk = sock->sk; 1450 struct net *net = sock_net(sk); 1451 struct unix_sock *u = unix_sk(sk); 1452 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); 1453 struct sock *other = NULL; 1454 int namelen = 0; /* fake GCC */ 1455 int err; 1456 unsigned int hash; 1457 struct sk_buff *skb; 1458 long timeo; 1459 struct scm_cookie tmp_scm; 1460 int max_level; 1461 int data_len = 0; 1462 1463 if (NULL == siocb->scm) 1464 siocb->scm = &tmp_scm; 1465 wait_for_unix_gc(); 1466 err = scm_send(sock, msg, siocb->scm, false); 1467 if (err < 0) 1468 return err; 1469 1470 err = -EOPNOTSUPP; 1471 if (msg->msg_flags&MSG_OOB) 1472 goto out; 1473 1474 if (msg->msg_namelen) { 1475 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1476 if (err < 0) 1477 goto out; 1478 namelen = err; 1479 } else { 1480 sunaddr = NULL; 1481 err = -ENOTCONN; 1482 other = unix_peer_get(sk); 1483 if (!other) 1484 goto out; 1485 } 1486 1487 if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr 1488 && (err = unix_autobind(sock)) != 0) 1489 goto out; 1490 1491 err = -EMSGSIZE; 1492 if (len > sk->sk_sndbuf - 32) 1493 goto out; 1494 1495 if (len > SKB_MAX_ALLOC) 1496 data_len = min_t(size_t, 1497 len - SKB_MAX_ALLOC, 1498 MAX_SKB_FRAGS * PAGE_SIZE); 1499 1500 skb = sock_alloc_send_pskb(sk, len - data_len, data_len, 1501 msg->msg_flags & MSG_DONTWAIT, &err, 1502 PAGE_ALLOC_COSTLY_ORDER); 1503 if (skb == NULL) 1504 goto out; 1505 1506 err = unix_scm_to_skb(siocb->scm, skb, true); 1507 if (err < 0) 1508 goto out_free; 1509 max_level = err + 1; 1510 unix_get_secdata(siocb->scm, skb); 1511 1512 skb_put(skb, len - data_len); 1513 skb->data_len = data_len; 1514 skb->len = len; 1515 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len); 1516 if (err) 1517 goto out_free; 1518 1519 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1520 1521restart: 1522 if (!other) { 1523 err = -ECONNRESET; 1524 if (sunaddr == NULL) 1525 goto out_free; 1526 1527 other = unix_find_other(net, sunaddr, namelen, sk->sk_type, 1528 hash, &err); 1529 if (other == NULL) 1530 goto out_free; 1531 } 1532 1533 if (sk_filter(other, skb) < 0) { 1534 /* Toss the packet but do not return any error to the sender */ 1535 err = len; 1536 goto out_free; 1537 } 1538 1539 unix_state_lock(other); 1540 err = -EPERM; 1541 if (!unix_may_send(sk, other)) 1542 goto out_unlock; 1543 1544 if (sock_flag(other, SOCK_DEAD)) { 1545 /* 1546 * Check with 1003.1g - what should 1547 * datagram error 1548 */ 1549 unix_state_unlock(other); 1550 sock_put(other); 1551 1552 err = 0; 1553 unix_state_lock(sk); 1554 if (unix_peer(sk) == other) { 1555 unix_peer(sk) = NULL; 1556 unix_state_unlock(sk); 1557 1558 unix_dgram_disconnected(sk, other); 1559 sock_put(other); 1560 err = -ECONNREFUSED; 1561 } else { 1562 unix_state_unlock(sk); 1563 } 1564 1565 other = NULL; 1566 if (err) 1567 goto out_free; 1568 goto restart; 1569 } 1570 1571 err = -EPIPE; 1572 if (other->sk_shutdown & RCV_SHUTDOWN) 1573 goto out_unlock; 1574 1575 if (sk->sk_type != SOCK_SEQPACKET) { 1576 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1577 if (err) 1578 goto out_unlock; 1579 } 1580 1581 if (unix_peer(other) != sk && unix_recvq_full(other)) { 1582 if (!timeo) { 1583 err = -EAGAIN; 1584 goto out_unlock; 1585 } 1586 1587 timeo = unix_wait_for_peer(other, timeo); 1588 1589 err = sock_intr_errno(timeo); 1590 if (signal_pending(current)) 1591 goto out_free; 1592 1593 goto restart; 1594 } 1595 1596 if (sock_flag(other, SOCK_RCVTSTAMP)) 1597 __net_timestamp(skb); 1598 maybe_add_creds(skb, sock, other); 1599 skb_queue_tail(&other->sk_receive_queue, skb); 1600 if (max_level > unix_sk(other)->recursion_level) 1601 unix_sk(other)->recursion_level = max_level; 1602 unix_state_unlock(other); 1603 other->sk_data_ready(other, len); 1604 sock_put(other); 1605 scm_destroy(siocb->scm); 1606 return len; 1607 1608out_unlock: 1609 unix_state_unlock(other); 1610out_free: 1611 kfree_skb(skb); 1612out: 1613 if (other) 1614 sock_put(other); 1615 scm_destroy(siocb->scm); 1616 return err; 1617} 1618 1619/* We use paged skbs for stream sockets, and limit occupancy to 32768 1620 * bytes, and a minimun of a full page. 1621 */ 1622#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) 1623 1624static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1625 struct msghdr *msg, size_t len) 1626{ 1627 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1628 struct sock *sk = sock->sk; 1629 struct sock *other = NULL; 1630 int err, size; 1631 struct sk_buff *skb; 1632 int sent = 0; 1633 struct scm_cookie tmp_scm; 1634 bool fds_sent = false; 1635 int max_level; 1636 int data_len; 1637 1638 if (NULL == siocb->scm) 1639 siocb->scm = &tmp_scm; 1640 wait_for_unix_gc(); 1641 err = scm_send(sock, msg, siocb->scm, false); 1642 if (err < 0) 1643 return err; 1644 1645 err = -EOPNOTSUPP; 1646 if (msg->msg_flags&MSG_OOB) 1647 goto out_err; 1648 1649 if (msg->msg_namelen) { 1650 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1651 goto out_err; 1652 } else { 1653 err = -ENOTCONN; 1654 other = unix_peer(sk); 1655 if (!other) 1656 goto out_err; 1657 } 1658 1659 if (sk->sk_shutdown & SEND_SHUTDOWN) 1660 goto pipe_err; 1661 1662 while (sent < len) { 1663 size = len - sent; 1664 1665 /* Keep two messages in the pipe so it schedules better */ 1666 size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); 1667 1668 /* allow fallback to order-0 allocations */ 1669 size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); 1670 1671 data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); 1672 1673 skb = sock_alloc_send_pskb(sk, size - data_len, data_len, 1674 msg->msg_flags & MSG_DONTWAIT, &err, 1675 get_order(UNIX_SKB_FRAGS_SZ)); 1676 if (!skb) 1677 goto out_err; 1678 1679 /* Only send the fds in the first buffer */ 1680 err = unix_scm_to_skb(siocb->scm, skb, !fds_sent); 1681 if (err < 0) { 1682 kfree_skb(skb); 1683 goto out_err; 1684 } 1685 max_level = err + 1; 1686 fds_sent = true; 1687 1688 skb_put(skb, size - data_len); 1689 skb->data_len = data_len; 1690 skb->len = size; 1691 err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 1692 sent, size); 1693 if (err) { 1694 kfree_skb(skb); 1695 goto out_err; 1696 } 1697 1698 unix_state_lock(other); 1699 1700 if (sock_flag(other, SOCK_DEAD) || 1701 (other->sk_shutdown & RCV_SHUTDOWN)) 1702 goto pipe_err_free; 1703 1704 maybe_add_creds(skb, sock, other); 1705 skb_queue_tail(&other->sk_receive_queue, skb); 1706 if (max_level > unix_sk(other)->recursion_level) 1707 unix_sk(other)->recursion_level = max_level; 1708 unix_state_unlock(other); 1709 other->sk_data_ready(other, size); 1710 sent += size; 1711 } 1712 1713 scm_destroy(siocb->scm); 1714 siocb->scm = NULL; 1715 1716 return sent; 1717 1718pipe_err_free: 1719 unix_state_unlock(other); 1720 kfree_skb(skb); 1721pipe_err: 1722 if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1723 send_sig(SIGPIPE, current, 0); 1724 err = -EPIPE; 1725out_err: 1726 scm_destroy(siocb->scm); 1727 siocb->scm = NULL; 1728 return sent ? : err; 1729} 1730 1731static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1732 struct msghdr *msg, size_t len) 1733{ 1734 int err; 1735 struct sock *sk = sock->sk; 1736 1737 err = sock_error(sk); 1738 if (err) 1739 return err; 1740 1741 if (sk->sk_state != TCP_ESTABLISHED) 1742 return -ENOTCONN; 1743 1744 if (msg->msg_namelen) 1745 msg->msg_namelen = 0; 1746 1747 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1748} 1749 1750static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock, 1751 struct msghdr *msg, size_t size, 1752 int flags) 1753{ 1754 struct sock *sk = sock->sk; 1755 1756 if (sk->sk_state != TCP_ESTABLISHED) 1757 return -ENOTCONN; 1758 1759 return unix_dgram_recvmsg(iocb, sock, msg, size, flags); 1760} 1761 1762static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1763{ 1764 struct unix_sock *u = unix_sk(sk); 1765 1766 if (u->addr) { 1767 msg->msg_namelen = u->addr->len; 1768 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1769 } 1770} 1771 1772static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1773 struct msghdr *msg, size_t size, 1774 int flags) 1775{ 1776 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1777 struct scm_cookie tmp_scm; 1778 struct sock *sk = sock->sk; 1779 struct unix_sock *u = unix_sk(sk); 1780 int noblock = flags & MSG_DONTWAIT; 1781 struct sk_buff *skb; 1782 int err; 1783 int peeked, skip; 1784 1785 err = -EOPNOTSUPP; 1786 if (flags&MSG_OOB) 1787 goto out; 1788 1789 err = mutex_lock_interruptible(&u->readlock); 1790 if (unlikely(err)) { 1791 /* recvmsg() in non blocking mode is supposed to return -EAGAIN 1792 * sk_rcvtimeo is not honored by mutex_lock_interruptible() 1793 */ 1794 err = noblock ? -EAGAIN : -ERESTARTSYS; 1795 goto out; 1796 } 1797 1798 skip = sk_peek_offset(sk, flags); 1799 1800 skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); 1801 if (!skb) { 1802 unix_state_lock(sk); 1803 /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ 1804 if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && 1805 (sk->sk_shutdown & RCV_SHUTDOWN)) 1806 err = 0; 1807 unix_state_unlock(sk); 1808 goto out_unlock; 1809 } 1810 1811 wake_up_interruptible_sync_poll(&u->peer_wait, 1812 POLLOUT | POLLWRNORM | POLLWRBAND); 1813 1814 if (msg->msg_name) 1815 unix_copy_addr(msg, skb->sk); 1816 1817 if (size > skb->len - skip) 1818 size = skb->len - skip; 1819 else if (size < skb->len - skip) 1820 msg->msg_flags |= MSG_TRUNC; 1821 1822 err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size); 1823 if (err) 1824 goto out_free; 1825 1826 if (sock_flag(sk, SOCK_RCVTSTAMP)) 1827 __sock_recv_timestamp(msg, sk, skb); 1828 1829 if (!siocb->scm) { 1830 siocb->scm = &tmp_scm; 1831 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1832 } 1833 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 1834 unix_set_secdata(siocb->scm, skb); 1835 1836 if (!(flags & MSG_PEEK)) { 1837 if (UNIXCB(skb).fp) 1838 unix_detach_fds(siocb->scm, skb); 1839 1840 sk_peek_offset_bwd(sk, skb->len); 1841 } else { 1842 /* It is questionable: on PEEK we could: 1843 - do not return fds - good, but too simple 8) 1844 - return fds, and do not return them on read (old strategy, 1845 apparently wrong) 1846 - clone fds (I chose it for now, it is the most universal 1847 solution) 1848 1849 POSIX 1003.1g does not actually define this clearly 1850 at all. POSIX 1003.1g doesn't define a lot of things 1851 clearly however! 1852 1853 */ 1854 1855 sk_peek_offset_fwd(sk, size); 1856 1857 if (UNIXCB(skb).fp) 1858 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1859 } 1860 err = (flags & MSG_TRUNC) ? skb->len - skip : size; 1861 1862 scm_recv(sock, msg, siocb->scm, flags); 1863 1864out_free: 1865 skb_free_datagram(sk, skb); 1866out_unlock: 1867 mutex_unlock(&u->readlock); 1868out: 1869 return err; 1870} 1871 1872/* 1873 * Sleep until more data has arrived. But check for races.. 1874 */ 1875static long unix_stream_data_wait(struct sock *sk, long timeo, 1876 struct sk_buff *last) 1877{ 1878 DEFINE_WAIT(wait); 1879 1880 unix_state_lock(sk); 1881 1882 for (;;) { 1883 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); 1884 1885 if (skb_peek_tail(&sk->sk_receive_queue) != last || 1886 sk->sk_err || 1887 (sk->sk_shutdown & RCV_SHUTDOWN) || 1888 signal_pending(current) || 1889 !timeo) 1890 break; 1891 1892 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1893 unix_state_unlock(sk); 1894 timeo = freezable_schedule_timeout(timeo); 1895 unix_state_lock(sk); 1896 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1897 } 1898 1899 finish_wait(sk_sleep(sk), &wait); 1900 unix_state_unlock(sk); 1901 return timeo; 1902} 1903 1904static unsigned int unix_skb_len(const struct sk_buff *skb) 1905{ 1906 return skb->len - UNIXCB(skb).consumed; 1907} 1908 1909static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1910 struct msghdr *msg, size_t size, 1911 int flags) 1912{ 1913 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1914 struct scm_cookie tmp_scm; 1915 struct sock *sk = sock->sk; 1916 struct unix_sock *u = unix_sk(sk); 1917 DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); 1918 int copied = 0; 1919 int noblock = flags & MSG_DONTWAIT; 1920 int check_creds = 0; 1921 int target; 1922 int err = 0; 1923 long timeo; 1924 int skip; 1925 1926 err = -EINVAL; 1927 if (sk->sk_state != TCP_ESTABLISHED) 1928 goto out; 1929 1930 err = -EOPNOTSUPP; 1931 if (flags&MSG_OOB) 1932 goto out; 1933 1934 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1935 timeo = sock_rcvtimeo(sk, noblock); 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 (unlikely(err)) { 1948 /* recvmsg() in non blocking mode is supposed to return -EAGAIN 1949 * sk_rcvtimeo is not honored by mutex_lock_interruptible() 1950 */ 1951 err = noblock ? -EAGAIN : -ERESTARTSYS; 1952 goto out; 1953 } 1954 1955 do { 1956 int chunk; 1957 struct sk_buff *skb, *last; 1958 1959 unix_state_lock(sk); 1960 last = skb = skb_peek(&sk->sk_receive_queue); 1961again: 1962 if (skb == NULL) { 1963 unix_sk(sk)->recursion_level = 0; 1964 if (copied >= target) 1965 goto unlock; 1966 1967 /* 1968 * POSIX 1003.1g mandates this order. 1969 */ 1970 1971 err = sock_error(sk); 1972 if (err) 1973 goto unlock; 1974 if (sk->sk_shutdown & RCV_SHUTDOWN) 1975 goto unlock; 1976 1977 unix_state_unlock(sk); 1978 err = -EAGAIN; 1979 if (!timeo) 1980 break; 1981 mutex_unlock(&u->readlock); 1982 1983 timeo = unix_stream_data_wait(sk, timeo, last); 1984 1985 if (signal_pending(current) 1986 || mutex_lock_interruptible(&u->readlock)) { 1987 err = sock_intr_errno(timeo); 1988 goto out; 1989 } 1990 1991 continue; 1992 unlock: 1993 unix_state_unlock(sk); 1994 break; 1995 } 1996 1997 skip = sk_peek_offset(sk, flags); 1998 while (skip >= unix_skb_len(skb)) { 1999 skip -= unix_skb_len(skb); 2000 last = skb; 2001 skb = skb_peek_next(skb, &sk->sk_receive_queue); 2002 if (!skb) 2003 goto again; 2004 } 2005 2006 unix_state_unlock(sk); 2007 2008 if (check_creds) { 2009 /* Never glue messages from different writers */ 2010 if ((UNIXCB(skb).pid != siocb->scm->pid) || 2011 !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) || 2012 !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid)) 2013 break; 2014 } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { 2015 /* Copy credentials */ 2016 scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); 2017 check_creds = 1; 2018 } 2019 2020 /* Copy address just once */ 2021 if (sunaddr) { 2022 unix_copy_addr(msg, skb->sk); 2023 sunaddr = NULL; 2024 } 2025 2026 chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size); 2027 if (skb_copy_datagram_iovec(skb, UNIXCB(skb).consumed + skip, 2028 msg->msg_iov, chunk)) { 2029 if (copied == 0) 2030 copied = -EFAULT; 2031 break; 2032 } 2033 copied += chunk; 2034 size -= chunk; 2035 2036 /* Mark read part of skb as used */ 2037 if (!(flags & MSG_PEEK)) { 2038 UNIXCB(skb).consumed += chunk; 2039 2040 sk_peek_offset_bwd(sk, chunk); 2041 2042 if (UNIXCB(skb).fp) 2043 unix_detach_fds(siocb->scm, skb); 2044 2045 if (unix_skb_len(skb)) 2046 break; 2047 2048 skb_unlink(skb, &sk->sk_receive_queue); 2049 consume_skb(skb); 2050 2051 if (siocb->scm->fp) 2052 break; 2053 } else { 2054 /* It is questionable, see note in unix_dgram_recvmsg. 2055 */ 2056 if (UNIXCB(skb).fp) 2057 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 2058 2059 sk_peek_offset_fwd(sk, chunk); 2060 2061 break; 2062 } 2063 } while (size); 2064 2065 mutex_unlock(&u->readlock); 2066 scm_recv(sock, msg, siocb->scm, flags); 2067out: 2068 return copied ? : err; 2069} 2070 2071static int unix_shutdown(struct socket *sock, int mode) 2072{ 2073 struct sock *sk = sock->sk; 2074 struct sock *other; 2075 2076 if (mode < SHUT_RD || mode > SHUT_RDWR) 2077 return -EINVAL; 2078 /* This maps: 2079 * SHUT_RD (0) -> RCV_SHUTDOWN (1) 2080 * SHUT_WR (1) -> SEND_SHUTDOWN (2) 2081 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3) 2082 */ 2083 ++mode; 2084 2085 unix_state_lock(sk); 2086 sk->sk_shutdown |= mode; 2087 other = unix_peer(sk); 2088 if (other) 2089 sock_hold(other); 2090 unix_state_unlock(sk); 2091 sk->sk_state_change(sk); 2092 2093 if (other && 2094 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 2095 2096 int peer_mode = 0; 2097 2098 if (mode&RCV_SHUTDOWN) 2099 peer_mode |= SEND_SHUTDOWN; 2100 if (mode&SEND_SHUTDOWN) 2101 peer_mode |= RCV_SHUTDOWN; 2102 unix_state_lock(other); 2103 other->sk_shutdown |= peer_mode; 2104 unix_state_unlock(other); 2105 other->sk_state_change(other); 2106 if (peer_mode == SHUTDOWN_MASK) 2107 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); 2108 else if (peer_mode & RCV_SHUTDOWN) 2109 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); 2110 } 2111 if (other) 2112 sock_put(other); 2113 2114 return 0; 2115} 2116 2117long unix_inq_len(struct sock *sk) 2118{ 2119 struct sk_buff *skb; 2120 long amount = 0; 2121 2122 if (sk->sk_state == TCP_LISTEN) 2123 return -EINVAL; 2124 2125 spin_lock(&sk->sk_receive_queue.lock); 2126 if (sk->sk_type == SOCK_STREAM || 2127 sk->sk_type == SOCK_SEQPACKET) { 2128 skb_queue_walk(&sk->sk_receive_queue, skb) 2129 amount += unix_skb_len(skb); 2130 } else { 2131 skb = skb_peek(&sk->sk_receive_queue); 2132 if (skb) 2133 amount = skb->len; 2134 } 2135 spin_unlock(&sk->sk_receive_queue.lock); 2136 2137 return amount; 2138} 2139EXPORT_SYMBOL_GPL(unix_inq_len); 2140 2141long unix_outq_len(struct sock *sk) 2142{ 2143 return sk_wmem_alloc_get(sk); 2144} 2145EXPORT_SYMBOL_GPL(unix_outq_len); 2146 2147static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 2148{ 2149 struct sock *sk = sock->sk; 2150 long amount = 0; 2151 int err; 2152 2153 switch (cmd) { 2154 case SIOCOUTQ: 2155 amount = unix_outq_len(sk); 2156 err = put_user(amount, (int __user *)arg); 2157 break; 2158 case SIOCINQ: 2159 amount = unix_inq_len(sk); 2160 if (amount < 0) 2161 err = amount; 2162 else 2163 err = put_user(amount, (int __user *)arg); 2164 break; 2165 default: 2166 err = -ENOIOCTLCMD; 2167 break; 2168 } 2169 return err; 2170} 2171 2172static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) 2173{ 2174 struct sock *sk = sock->sk; 2175 unsigned int mask; 2176 2177 sock_poll_wait(file, sk_sleep(sk), wait); 2178 mask = 0; 2179 2180 /* exceptional events? */ 2181 if (sk->sk_err) 2182 mask |= POLLERR; 2183 if (sk->sk_shutdown == SHUTDOWN_MASK) 2184 mask |= POLLHUP; 2185 if (sk->sk_shutdown & RCV_SHUTDOWN) 2186 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2187 2188 /* readable? */ 2189 if (!skb_queue_empty(&sk->sk_receive_queue)) 2190 mask |= POLLIN | POLLRDNORM; 2191 2192 /* Connection-based need to check for termination and startup */ 2193 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 2194 sk->sk_state == TCP_CLOSE) 2195 mask |= POLLHUP; 2196 2197 /* 2198 * we set writable also when the other side has shut down the 2199 * connection. This prevents stuck sockets. 2200 */ 2201 if (unix_writable(sk)) 2202 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2203 2204 return mask; 2205} 2206 2207static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, 2208 poll_table *wait) 2209{ 2210 struct sock *sk = sock->sk, *other; 2211 unsigned int mask, writable; 2212 2213 sock_poll_wait(file, sk_sleep(sk), wait); 2214 mask = 0; 2215 2216 /* exceptional events? */ 2217 if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) 2218 mask |= POLLERR | 2219 (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0); 2220 2221 if (sk->sk_shutdown & RCV_SHUTDOWN) 2222 mask |= POLLRDHUP | POLLIN | POLLRDNORM; 2223 if (sk->sk_shutdown == SHUTDOWN_MASK) 2224 mask |= POLLHUP; 2225 2226 /* readable? */ 2227 if (!skb_queue_empty(&sk->sk_receive_queue)) 2228 mask |= POLLIN | POLLRDNORM; 2229 2230 /* Connection-based need to check for termination and startup */ 2231 if (sk->sk_type == SOCK_SEQPACKET) { 2232 if (sk->sk_state == TCP_CLOSE) 2233 mask |= POLLHUP; 2234 /* connection hasn't started yet? */ 2235 if (sk->sk_state == TCP_SYN_SENT) 2236 return mask; 2237 } 2238 2239 /* No write status requested, avoid expensive OUT tests. */ 2240 if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) 2241 return mask; 2242 2243 writable = unix_writable(sk); 2244 other = unix_peer_get(sk); 2245 if (other) { 2246 if (unix_peer(other) != sk) { 2247 sock_poll_wait(file, &unix_sk(other)->peer_wait, wait); 2248 if (unix_recvq_full(other)) 2249 writable = 0; 2250 } 2251 sock_put(other); 2252 } 2253 2254 if (writable) 2255 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 2256 else 2257 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); 2258 2259 return mask; 2260} 2261 2262#ifdef CONFIG_PROC_FS 2263 2264#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) 2265 2266#define get_bucket(x) ((x) >> BUCKET_SPACE) 2267#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1)) 2268#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) 2269 2270static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) 2271{ 2272 unsigned long offset = get_offset(*pos); 2273 unsigned long bucket = get_bucket(*pos); 2274 struct sock *sk; 2275 unsigned long count = 0; 2276 2277 for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) { 2278 if (sock_net(sk) != seq_file_net(seq)) 2279 continue; 2280 if (++count == offset) 2281 break; 2282 } 2283 2284 return sk; 2285} 2286 2287static struct sock *unix_next_socket(struct seq_file *seq, 2288 struct sock *sk, 2289 loff_t *pos) 2290{ 2291 unsigned long bucket; 2292 2293 while (sk > (struct sock *)SEQ_START_TOKEN) { 2294 sk = sk_next(sk); 2295 if (!sk) 2296 goto next_bucket; 2297 if (sock_net(sk) == seq_file_net(seq)) 2298 return sk; 2299 } 2300 2301 do { 2302 sk = unix_from_bucket(seq, pos); 2303 if (sk) 2304 return sk; 2305 2306next_bucket: 2307 bucket = get_bucket(*pos) + 1; 2308 *pos = set_bucket_offset(bucket, 1); 2309 } while (bucket < ARRAY_SIZE(unix_socket_table)); 2310 2311 return NULL; 2312} 2313 2314static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 2315 __acquires(unix_table_lock) 2316{ 2317 spin_lock(&unix_table_lock); 2318 2319 if (!*pos) 2320 return SEQ_START_TOKEN; 2321 2322 if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table)) 2323 return NULL; 2324 2325 return unix_next_socket(seq, NULL, pos); 2326} 2327 2328static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2329{ 2330 ++*pos; 2331 return unix_next_socket(seq, v, pos); 2332} 2333 2334static void unix_seq_stop(struct seq_file *seq, void *v) 2335 __releases(unix_table_lock) 2336{ 2337 spin_unlock(&unix_table_lock); 2338} 2339 2340static int unix_seq_show(struct seq_file *seq, void *v) 2341{ 2342 2343 if (v == SEQ_START_TOKEN) 2344 seq_puts(seq, "Num RefCount Protocol Flags Type St " 2345 "Inode Path\n"); 2346 else { 2347 struct sock *s = v; 2348 struct unix_sock *u = unix_sk(s); 2349 unix_state_lock(s); 2350 2351 seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", 2352 s, 2353 atomic_read(&s->sk_refcnt), 2354 0, 2355 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 2356 s->sk_type, 2357 s->sk_socket ? 2358 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 2359 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 2360 sock_i_ino(s)); 2361 2362 if (u->addr) { 2363 int i, len; 2364 seq_putc(seq, ' '); 2365 2366 i = 0; 2367 len = u->addr->len - sizeof(short); 2368 if (!UNIX_ABSTRACT(s)) 2369 len--; 2370 else { 2371 seq_putc(seq, '@'); 2372 i++; 2373 } 2374 for ( ; i < len; i++) 2375 seq_putc(seq, u->addr->name->sun_path[i]); 2376 } 2377 unix_state_unlock(s); 2378 seq_putc(seq, '\n'); 2379 } 2380 2381 return 0; 2382} 2383 2384static const struct seq_operations unix_seq_ops = { 2385 .start = unix_seq_start, 2386 .next = unix_seq_next, 2387 .stop = unix_seq_stop, 2388 .show = unix_seq_show, 2389}; 2390 2391static int unix_seq_open(struct inode *inode, struct file *file) 2392{ 2393 return seq_open_net(inode, file, &unix_seq_ops, 2394 sizeof(struct seq_net_private)); 2395} 2396 2397static const struct file_operations unix_seq_fops = { 2398 .owner = THIS_MODULE, 2399 .open = unix_seq_open, 2400 .read = seq_read, 2401 .llseek = seq_lseek, 2402 .release = seq_release_net, 2403}; 2404 2405#endif 2406 2407static const struct net_proto_family unix_family_ops = { 2408 .family = PF_UNIX, 2409 .create = unix_create, 2410 .owner = THIS_MODULE, 2411}; 2412 2413 2414static int __net_init unix_net_init(struct net *net) 2415{ 2416 int error = -ENOMEM; 2417 2418 net->unx.sysctl_max_dgram_qlen = 10; 2419 if (unix_sysctl_register(net)) 2420 goto out; 2421 2422#ifdef CONFIG_PROC_FS 2423 if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) { 2424 unix_sysctl_unregister(net); 2425 goto out; 2426 } 2427#endif 2428 error = 0; 2429out: 2430 return error; 2431} 2432 2433static void __net_exit unix_net_exit(struct net *net) 2434{ 2435 unix_sysctl_unregister(net); 2436 remove_proc_entry("unix", net->proc_net); 2437} 2438 2439static struct pernet_operations unix_net_ops = { 2440 .init = unix_net_init, 2441 .exit = unix_net_exit, 2442}; 2443 2444static int __init af_unix_init(void) 2445{ 2446 int rc = -1; 2447 2448 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb)); 2449 2450 rc = proto_register(&unix_proto, 1); 2451 if (rc != 0) { 2452 pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); 2453 goto out; 2454 } 2455 2456 sock_register(&unix_family_ops); 2457 register_pernet_subsys(&unix_net_ops); 2458out: 2459 return rc; 2460} 2461 2462static void __exit af_unix_exit(void) 2463{ 2464 sock_unregister(PF_UNIX); 2465 proto_unregister(&unix_proto); 2466 unregister_pernet_subsys(&unix_net_ops); 2467} 2468 2469/* Earlier than device_initcall() so that other drivers invoking 2470 request_module() don't end up in a loop when modprobe tries 2471 to use a UNIX socket. But later than subsys_initcall() because 2472 we depend on stuff initialised there */ 2473fs_initcall(af_unix_init); 2474module_exit(af_unix_exit); 2475 2476MODULE_LICENSE("GPL"); 2477MODULE_ALIAS_NETPROTO(PF_UNIX); 2478