1 /* 2 * NET4: Implementation of BSD Unix domain sockets. 3 * 4 * Authors: Alan Cox, <alan.cox@linux.org> 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 * Version: $Id: af_unix.c,v 1.133 2002/02/08 03:57:19 davem Exp $ 12 * 13 * Fixes: 14 * Linus Torvalds : Assorted bug cures. 15 * Niibe Yutaka : async I/O support. 16 * Carsten Paeth : PF_UNIX check, address fixes. 17 * Alan Cox : Limit size of allocated blocks. 18 * Alan Cox : Fixed the stupid socketpair bug. 19 * Alan Cox : BSD compatibility fine tuning. 20 * Alan Cox : Fixed a bug in connect when interrupted. 21 * Alan Cox : Sorted out a proper draft version of 22 * file descriptor passing hacked up from 23 * Mike Shaver's work. 24 * Marty Leisner : Fixes to fd passing 25 * Nick Nevin : recvmsg bugfix. 26 * Alan Cox : Started proper garbage collector 27 * Heiko EiBfeldt : Missing verify_area check 28 * Alan Cox : Started POSIXisms 29 * Andreas Schwab : Replace inode by dentry for proper 30 * reference counting 31 * Kirk Petersen : Made this a module 32 * Christoph Rohland : Elegant non-blocking accept/connect algorithm. 33 * Lots of bug fixes. 34 * Alexey Kuznetosv : Repaired (I hope) bugs introduces 35 * by above two patches. 36 * Andrea Arcangeli : If possible we block in connect(2) 37 * if the max backlog of the listen socket 38 * is been reached. This won't break 39 * old apps and it will avoid huge amount 40 * of socks hashed (this for unix_gc() 41 * performances reasons). 42 * Security fix that limits the max 43 * number of socks to 2*max_files and 44 * the number of skb queueable in the 45 * dgram receiver. 46 * Artur Skawina : Hash function optimizations 47 * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8) 48 * Malcolm Beattie : Set peercred for socketpair 49 * Michal Ostrowski : Module initialization cleanup. 50 * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT, 51 * the core infrastructure is doing that 52 * for all net proto families now (2.5.69+) 53 * 54 * 55 * Known differences from reference BSD that was tested: 56 * 57 * [TO FIX] 58 * ECONNREFUSED is not returned from one end of a connected() socket to the 59 * other the moment one end closes. 60 * fstat() doesn't return st_dev=0, and give the blksize as high water mark 61 * and a fake inode identifier (nor the BSD first socket fstat twice bug). 62 * [NOT TO FIX] 63 * accept() returns a path name even if the connecting socket has closed 64 * in the meantime (BSD loses the path and gives up). 65 * accept() returns 0 length path for an unbound connector. BSD returns 16 66 * and a null first byte in the path (but not for gethost/peername - BSD bug ??) 67 * socketpair(...SOCK_RAW..) doesn't panic the kernel. 68 * BSD af_unix apparently has connect forgetting to block properly. 69 * (need to check this with the POSIX spec in detail) 70 * 71 * Differences from 2.0.0-11-... (ANK) 72 * Bug fixes and improvements. 73 * - client shutdown killed server socket. 74 * - removed all useless cli/sti pairs. 75 * 76 * Semantic changes/extensions. 77 * - generic control message passing. 78 * - SCM_CREDENTIALS control message. 79 * - "Abstract" (not FS based) socket bindings. 80 * Abstract names are sequences of bytes (not zero terminated) 81 * started by 0, so that this name space does not intersect 82 * with BSD names. 83 */ 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/sock.h> 107 #include <net/tcp_states.h> 108 #include <net/af_unix.h> 109 #include <linux/proc_fs.h> 110 #include <linux/seq_file.h> 111 #include <net/scm.h> 112 #include <linux/init.h> 113 #include <linux/poll.h> 114 #include <linux/smp_lock.h> 115 #include <linux/rtnetlink.h> 116 #include <linux/mount.h> 117 #include <net/checksum.h> 118 #include <linux/security.h> 119 120 int sysctl_unix_max_dgram_qlen __read_mostly = 10; 121 122 struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1]; 123 DEFINE_SPINLOCK(unix_table_lock); 124 static atomic_t unix_nr_socks = ATOMIC_INIT(0); 125 126 #define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE]) 127 128 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE) 129 130 #ifdef CONFIG_SECURITY_NETWORK 131 static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 132 { 133 memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); 134 } 135 136 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 137 { 138 scm->secid = *UNIXSID(skb); 139 } 140 #else 141 static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) 142 { } 143 144 static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) 145 { } 146 #endif /* CONFIG_SECURITY_NETWORK */ 147 148 /* 149 * SMP locking strategy: 150 * hash table is protected with spinlock unix_table_lock 151 * each socket state is protected by separate rwlock. 152 */ 153 154 static inline unsigned unix_hash_fold(__wsum n) 155 { 156 unsigned hash = (__force unsigned)n; 157 hash ^= hash>>16; 158 hash ^= hash>>8; 159 return hash&(UNIX_HASH_SIZE-1); 160 } 161 162 #define unix_peer(sk) (unix_sk(sk)->peer) 163 164 static inline int unix_our_peer(struct sock *sk, struct sock *osk) 165 { 166 return unix_peer(osk) == sk; 167 } 168 169 static inline int unix_may_send(struct sock *sk, struct sock *osk) 170 { 171 return (unix_peer(osk) == NULL || unix_our_peer(sk, osk)); 172 } 173 174 static struct sock *unix_peer_get(struct sock *s) 175 { 176 struct sock *peer; 177 178 unix_state_rlock(s); 179 peer = unix_peer(s); 180 if (peer) 181 sock_hold(peer); 182 unix_state_runlock(s); 183 return peer; 184 } 185 186 static inline void unix_release_addr(struct unix_address *addr) 187 { 188 if (atomic_dec_and_test(&addr->refcnt)) 189 kfree(addr); 190 } 191 192 /* 193 * Check unix socket name: 194 * - should be not zero length. 195 * - if started by not zero, should be NULL terminated (FS object) 196 * - if started by zero, it is abstract name. 197 */ 198 199 static int unix_mkname(struct sockaddr_un * sunaddr, int len, unsigned *hashp) 200 { 201 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 202 return -EINVAL; 203 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 204 return -EINVAL; 205 if (sunaddr->sun_path[0]) { 206 /* 207 * This may look like an off by one error but it is a bit more 208 * subtle. 108 is the longest valid AF_UNIX path for a binding. 209 * sun_path[108] doesnt as such exist. However in kernel space 210 * we are guaranteed that it is a valid memory location in our 211 * kernel address buffer. 212 */ 213 ((char *)sunaddr)[len]=0; 214 len = strlen(sunaddr->sun_path)+1+sizeof(short); 215 return len; 216 } 217 218 *hashp = unix_hash_fold(csum_partial((char*)sunaddr, len, 0)); 219 return len; 220 } 221 222 static void __unix_remove_socket(struct sock *sk) 223 { 224 sk_del_node_init(sk); 225 } 226 227 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 228 { 229 BUG_TRAP(sk_unhashed(sk)); 230 sk_add_node(sk, list); 231 } 232 233 static inline void unix_remove_socket(struct sock *sk) 234 { 235 spin_lock(&unix_table_lock); 236 __unix_remove_socket(sk); 237 spin_unlock(&unix_table_lock); 238 } 239 240 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 241 { 242 spin_lock(&unix_table_lock); 243 __unix_insert_socket(list, sk); 244 spin_unlock(&unix_table_lock); 245 } 246 247 static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname, 248 int len, int type, unsigned hash) 249 { 250 struct sock *s; 251 struct hlist_node *node; 252 253 sk_for_each(s, node, &unix_socket_table[hash ^ type]) { 254 struct unix_sock *u = unix_sk(s); 255 256 if (u->addr->len == len && 257 !memcmp(u->addr->name, sunname, len)) 258 goto found; 259 } 260 s = NULL; 261 found: 262 return s; 263 } 264 265 static inline struct sock *unix_find_socket_byname(struct sockaddr_un *sunname, 266 int len, int type, 267 unsigned hash) 268 { 269 struct sock *s; 270 271 spin_lock(&unix_table_lock); 272 s = __unix_find_socket_byname(sunname, len, type, hash); 273 if (s) 274 sock_hold(s); 275 spin_unlock(&unix_table_lock); 276 return s; 277 } 278 279 static struct sock *unix_find_socket_byinode(struct inode *i) 280 { 281 struct sock *s; 282 struct hlist_node *node; 283 284 spin_lock(&unix_table_lock); 285 sk_for_each(s, node, 286 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { 287 struct dentry *dentry = unix_sk(s)->dentry; 288 289 if(dentry && dentry->d_inode == i) 290 { 291 sock_hold(s); 292 goto found; 293 } 294 } 295 s = NULL; 296 found: 297 spin_unlock(&unix_table_lock); 298 return s; 299 } 300 301 static inline int unix_writable(struct sock *sk) 302 { 303 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; 304 } 305 306 static void unix_write_space(struct sock *sk) 307 { 308 read_lock(&sk->sk_callback_lock); 309 if (unix_writable(sk)) { 310 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) 311 wake_up_interruptible(sk->sk_sleep); 312 sk_wake_async(sk, 2, POLL_OUT); 313 } 314 read_unlock(&sk->sk_callback_lock); 315 } 316 317 /* When dgram socket disconnects (or changes its peer), we clear its receive 318 * queue of packets arrived from previous peer. First, it allows to do 319 * flow control based only on wmem_alloc; second, sk connected to peer 320 * may receive messages only from that peer. */ 321 static void unix_dgram_disconnected(struct sock *sk, struct sock *other) 322 { 323 if (!skb_queue_empty(&sk->sk_receive_queue)) { 324 skb_queue_purge(&sk->sk_receive_queue); 325 wake_up_interruptible_all(&unix_sk(sk)->peer_wait); 326 327 /* If one link of bidirectional dgram pipe is disconnected, 328 * we signal error. Messages are lost. Do not make this, 329 * when peer was not connected to us. 330 */ 331 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { 332 other->sk_err = ECONNRESET; 333 other->sk_error_report(other); 334 } 335 } 336 } 337 338 static void unix_sock_destructor(struct sock *sk) 339 { 340 struct unix_sock *u = unix_sk(sk); 341 342 skb_queue_purge(&sk->sk_receive_queue); 343 344 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); 345 BUG_TRAP(sk_unhashed(sk)); 346 BUG_TRAP(!sk->sk_socket); 347 if (!sock_flag(sk, SOCK_DEAD)) { 348 printk("Attempt to release alive unix socket: %p\n", sk); 349 return; 350 } 351 352 if (u->addr) 353 unix_release_addr(u->addr); 354 355 atomic_dec(&unix_nr_socks); 356 #ifdef UNIX_REFCNT_DEBUG 357 printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk, atomic_read(&unix_nr_socks)); 358 #endif 359 } 360 361 static int unix_release_sock (struct sock *sk, int embrion) 362 { 363 struct unix_sock *u = unix_sk(sk); 364 struct dentry *dentry; 365 struct vfsmount *mnt; 366 struct sock *skpair; 367 struct sk_buff *skb; 368 int state; 369 370 unix_remove_socket(sk); 371 372 /* Clear state */ 373 unix_state_wlock(sk); 374 sock_orphan(sk); 375 sk->sk_shutdown = SHUTDOWN_MASK; 376 dentry = u->dentry; 377 u->dentry = NULL; 378 mnt = u->mnt; 379 u->mnt = NULL; 380 state = sk->sk_state; 381 sk->sk_state = TCP_CLOSE; 382 unix_state_wunlock(sk); 383 384 wake_up_interruptible_all(&u->peer_wait); 385 386 skpair=unix_peer(sk); 387 388 if (skpair!=NULL) { 389 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { 390 unix_state_wlock(skpair); 391 /* No more writes */ 392 skpair->sk_shutdown = SHUTDOWN_MASK; 393 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) 394 skpair->sk_err = ECONNRESET; 395 unix_state_wunlock(skpair); 396 skpair->sk_state_change(skpair); 397 read_lock(&skpair->sk_callback_lock); 398 sk_wake_async(skpair,1,POLL_HUP); 399 read_unlock(&skpair->sk_callback_lock); 400 } 401 sock_put(skpair); /* It may now die */ 402 unix_peer(sk) = NULL; 403 } 404 405 /* Try to flush out this socket. Throw out buffers at least */ 406 407 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { 408 if (state==TCP_LISTEN) 409 unix_release_sock(skb->sk, 1); 410 /* passed fds are erased in the kfree_skb hook */ 411 kfree_skb(skb); 412 } 413 414 if (dentry) { 415 dput(dentry); 416 mntput(mnt); 417 } 418 419 sock_put(sk); 420 421 /* ---- Socket is dead now and most probably destroyed ---- */ 422 423 /* 424 * Fixme: BSD difference: In BSD all sockets connected to use get 425 * ECONNRESET and we die on the spot. In Linux we behave 426 * like files and pipes do and wait for the last 427 * dereference. 428 * 429 * Can't we simply set sock->err? 430 * 431 * What the above comment does talk about? --ANK(980817) 432 */ 433 434 if (atomic_read(&unix_tot_inflight)) 435 unix_gc(); /* Garbage collect fds */ 436 437 return 0; 438 } 439 440 static int unix_listen(struct socket *sock, int backlog) 441 { 442 int err; 443 struct sock *sk = sock->sk; 444 struct unix_sock *u = unix_sk(sk); 445 446 err = -EOPNOTSUPP; 447 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET) 448 goto out; /* Only stream/seqpacket sockets accept */ 449 err = -EINVAL; 450 if (!u->addr) 451 goto out; /* No listens on an unbound socket */ 452 unix_state_wlock(sk); 453 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 454 goto out_unlock; 455 if (backlog > sk->sk_max_ack_backlog) 456 wake_up_interruptible_all(&u->peer_wait); 457 sk->sk_max_ack_backlog = backlog; 458 sk->sk_state = TCP_LISTEN; 459 /* set credentials so connect can copy them */ 460 sk->sk_peercred.pid = current->tgid; 461 sk->sk_peercred.uid = current->euid; 462 sk->sk_peercred.gid = current->egid; 463 err = 0; 464 465 out_unlock: 466 unix_state_wunlock(sk); 467 out: 468 return err; 469 } 470 471 static int unix_release(struct socket *); 472 static int unix_bind(struct socket *, struct sockaddr *, int); 473 static int unix_stream_connect(struct socket *, struct sockaddr *, 474 int addr_len, int flags); 475 static int unix_socketpair(struct socket *, struct socket *); 476 static int unix_accept(struct socket *, struct socket *, int); 477 static int unix_getname(struct socket *, struct sockaddr *, int *, int); 478 static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 479 static int unix_ioctl(struct socket *, unsigned int, unsigned long); 480 static int unix_shutdown(struct socket *, int); 481 static int unix_stream_sendmsg(struct kiocb *, struct socket *, 482 struct msghdr *, size_t); 483 static int unix_stream_recvmsg(struct kiocb *, struct socket *, 484 struct msghdr *, size_t, int); 485 static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 486 struct msghdr *, size_t); 487 static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 488 struct msghdr *, size_t, int); 489 static int unix_dgram_connect(struct socket *, struct sockaddr *, 490 int, int); 491 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 492 struct msghdr *, size_t); 493 494 static const struct proto_ops unix_stream_ops = { 495 .family = PF_UNIX, 496 .owner = THIS_MODULE, 497 .release = unix_release, 498 .bind = unix_bind, 499 .connect = unix_stream_connect, 500 .socketpair = unix_socketpair, 501 .accept = unix_accept, 502 .getname = unix_getname, 503 .poll = unix_poll, 504 .ioctl = unix_ioctl, 505 .listen = unix_listen, 506 .shutdown = unix_shutdown, 507 .setsockopt = sock_no_setsockopt, 508 .getsockopt = sock_no_getsockopt, 509 .sendmsg = unix_stream_sendmsg, 510 .recvmsg = unix_stream_recvmsg, 511 .mmap = sock_no_mmap, 512 .sendpage = sock_no_sendpage, 513 }; 514 515 static const struct proto_ops unix_dgram_ops = { 516 .family = PF_UNIX, 517 .owner = THIS_MODULE, 518 .release = unix_release, 519 .bind = unix_bind, 520 .connect = unix_dgram_connect, 521 .socketpair = unix_socketpair, 522 .accept = sock_no_accept, 523 .getname = unix_getname, 524 .poll = datagram_poll, 525 .ioctl = unix_ioctl, 526 .listen = sock_no_listen, 527 .shutdown = unix_shutdown, 528 .setsockopt = sock_no_setsockopt, 529 .getsockopt = sock_no_getsockopt, 530 .sendmsg = unix_dgram_sendmsg, 531 .recvmsg = unix_dgram_recvmsg, 532 .mmap = sock_no_mmap, 533 .sendpage = sock_no_sendpage, 534 }; 535 536 static const struct proto_ops unix_seqpacket_ops = { 537 .family = PF_UNIX, 538 .owner = THIS_MODULE, 539 .release = unix_release, 540 .bind = unix_bind, 541 .connect = unix_stream_connect, 542 .socketpair = unix_socketpair, 543 .accept = unix_accept, 544 .getname = unix_getname, 545 .poll = datagram_poll, 546 .ioctl = unix_ioctl, 547 .listen = unix_listen, 548 .shutdown = unix_shutdown, 549 .setsockopt = sock_no_setsockopt, 550 .getsockopt = sock_no_getsockopt, 551 .sendmsg = unix_seqpacket_sendmsg, 552 .recvmsg = unix_dgram_recvmsg, 553 .mmap = sock_no_mmap, 554 .sendpage = sock_no_sendpage, 555 }; 556 557 static struct proto unix_proto = { 558 .name = "UNIX", 559 .owner = THIS_MODULE, 560 .obj_size = sizeof(struct unix_sock), 561 }; 562 563 /* 564 * AF_UNIX sockets do not interact with hardware, hence they 565 * dont trigger interrupts - so it's safe for them to have 566 * bh-unsafe locking for their sk_receive_queue.lock. Split off 567 * this special lock-class by reinitializing the spinlock key: 568 */ 569 static struct lock_class_key af_unix_sk_receive_queue_lock_key; 570 571 static struct sock * unix_create1(struct socket *sock) 572 { 573 struct sock *sk = NULL; 574 struct unix_sock *u; 575 576 if (atomic_read(&unix_nr_socks) >= 2*get_max_files()) 577 goto out; 578 579 sk = sk_alloc(PF_UNIX, GFP_KERNEL, &unix_proto, 1); 580 if (!sk) 581 goto out; 582 583 atomic_inc(&unix_nr_socks); 584 585 sock_init_data(sock,sk); 586 lockdep_set_class(&sk->sk_receive_queue.lock, 587 &af_unix_sk_receive_queue_lock_key); 588 589 sk->sk_write_space = unix_write_space; 590 sk->sk_max_ack_backlog = sysctl_unix_max_dgram_qlen; 591 sk->sk_destruct = unix_sock_destructor; 592 u = unix_sk(sk); 593 u->dentry = NULL; 594 u->mnt = NULL; 595 spin_lock_init(&u->lock); 596 atomic_set(&u->inflight, sock ? 0 : -1); 597 mutex_init(&u->readlock); /* single task reading lock */ 598 init_waitqueue_head(&u->peer_wait); 599 unix_insert_socket(unix_sockets_unbound, sk); 600 out: 601 return sk; 602 } 603 604 static int unix_create(struct socket *sock, int protocol) 605 { 606 if (protocol && protocol != PF_UNIX) 607 return -EPROTONOSUPPORT; 608 609 sock->state = SS_UNCONNECTED; 610 611 switch (sock->type) { 612 case SOCK_STREAM: 613 sock->ops = &unix_stream_ops; 614 break; 615 /* 616 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 617 * nothing uses it. 618 */ 619 case SOCK_RAW: 620 sock->type=SOCK_DGRAM; 621 case SOCK_DGRAM: 622 sock->ops = &unix_dgram_ops; 623 break; 624 case SOCK_SEQPACKET: 625 sock->ops = &unix_seqpacket_ops; 626 break; 627 default: 628 return -ESOCKTNOSUPPORT; 629 } 630 631 return unix_create1(sock) ? 0 : -ENOMEM; 632 } 633 634 static int unix_release(struct socket *sock) 635 { 636 struct sock *sk = sock->sk; 637 638 if (!sk) 639 return 0; 640 641 sock->sk = NULL; 642 643 return unix_release_sock (sk, 0); 644 } 645 646 static int unix_autobind(struct socket *sock) 647 { 648 struct sock *sk = sock->sk; 649 struct unix_sock *u = unix_sk(sk); 650 static u32 ordernum = 1; 651 struct unix_address * addr; 652 int err; 653 654 mutex_lock(&u->readlock); 655 656 err = 0; 657 if (u->addr) 658 goto out; 659 660 err = -ENOMEM; 661 addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 662 if (!addr) 663 goto out; 664 665 addr->name->sun_family = AF_UNIX; 666 atomic_set(&addr->refcnt, 1); 667 668 retry: 669 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 670 addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0)); 671 672 spin_lock(&unix_table_lock); 673 ordernum = (ordernum+1)&0xFFFFF; 674 675 if (__unix_find_socket_byname(addr->name, addr->len, sock->type, 676 addr->hash)) { 677 spin_unlock(&unix_table_lock); 678 /* Sanity yield. It is unusual case, but yet... */ 679 if (!(ordernum&0xFF)) 680 yield(); 681 goto retry; 682 } 683 addr->hash ^= sk->sk_type; 684 685 __unix_remove_socket(sk); 686 u->addr = addr; 687 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 688 spin_unlock(&unix_table_lock); 689 err = 0; 690 691 out: mutex_unlock(&u->readlock); 692 return err; 693 } 694 695 static struct sock *unix_find_other(struct sockaddr_un *sunname, int len, 696 int type, unsigned hash, int *error) 697 { 698 struct sock *u; 699 struct nameidata nd; 700 int err = 0; 701 702 if (sunname->sun_path[0]) { 703 err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd); 704 if (err) 705 goto fail; 706 err = vfs_permission(&nd, MAY_WRITE); 707 if (err) 708 goto put_fail; 709 710 err = -ECONNREFUSED; 711 if (!S_ISSOCK(nd.dentry->d_inode->i_mode)) 712 goto put_fail; 713 u=unix_find_socket_byinode(nd.dentry->d_inode); 714 if (!u) 715 goto put_fail; 716 717 if (u->sk_type == type) 718 touch_atime(nd.mnt, nd.dentry); 719 720 path_release(&nd); 721 722 err=-EPROTOTYPE; 723 if (u->sk_type != type) { 724 sock_put(u); 725 goto fail; 726 } 727 } else { 728 err = -ECONNREFUSED; 729 u=unix_find_socket_byname(sunname, len, type, hash); 730 if (u) { 731 struct dentry *dentry; 732 dentry = unix_sk(u)->dentry; 733 if (dentry) 734 touch_atime(unix_sk(u)->mnt, dentry); 735 } else 736 goto fail; 737 } 738 return u; 739 740 put_fail: 741 path_release(&nd); 742 fail: 743 *error=err; 744 return NULL; 745 } 746 747 748 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 749 { 750 struct sock *sk = sock->sk; 751 struct unix_sock *u = unix_sk(sk); 752 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 753 struct dentry * dentry = NULL; 754 struct nameidata nd; 755 int err; 756 unsigned hash; 757 struct unix_address *addr; 758 struct hlist_head *list; 759 760 err = -EINVAL; 761 if (sunaddr->sun_family != AF_UNIX) 762 goto out; 763 764 if (addr_len==sizeof(short)) { 765 err = unix_autobind(sock); 766 goto out; 767 } 768 769 err = unix_mkname(sunaddr, addr_len, &hash); 770 if (err < 0) 771 goto out; 772 addr_len = err; 773 774 mutex_lock(&u->readlock); 775 776 err = -EINVAL; 777 if (u->addr) 778 goto out_up; 779 780 err = -ENOMEM; 781 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 782 if (!addr) 783 goto out_up; 784 785 memcpy(addr->name, sunaddr, addr_len); 786 addr->len = addr_len; 787 addr->hash = hash ^ sk->sk_type; 788 atomic_set(&addr->refcnt, 1); 789 790 if (sunaddr->sun_path[0]) { 791 unsigned int mode; 792 err = 0; 793 /* 794 * Get the parent directory, calculate the hash for last 795 * component. 796 */ 797 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd); 798 if (err) 799 goto out_mknod_parent; 800 801 dentry = lookup_create(&nd, 0); 802 err = PTR_ERR(dentry); 803 if (IS_ERR(dentry)) 804 goto out_mknod_unlock; 805 806 /* 807 * All right, let's create it. 808 */ 809 mode = S_IFSOCK | 810 (SOCK_INODE(sock)->i_mode & ~current->fs->umask); 811 err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0); 812 if (err) 813 goto out_mknod_dput; 814 mutex_unlock(&nd.dentry->d_inode->i_mutex); 815 dput(nd.dentry); 816 nd.dentry = dentry; 817 818 addr->hash = UNIX_HASH_SIZE; 819 } 820 821 spin_lock(&unix_table_lock); 822 823 if (!sunaddr->sun_path[0]) { 824 err = -EADDRINUSE; 825 if (__unix_find_socket_byname(sunaddr, addr_len, 826 sk->sk_type, hash)) { 827 unix_release_addr(addr); 828 goto out_unlock; 829 } 830 831 list = &unix_socket_table[addr->hash]; 832 } else { 833 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)]; 834 u->dentry = nd.dentry; 835 u->mnt = nd.mnt; 836 } 837 838 err = 0; 839 __unix_remove_socket(sk); 840 u->addr = addr; 841 __unix_insert_socket(list, sk); 842 843 out_unlock: 844 spin_unlock(&unix_table_lock); 845 out_up: 846 mutex_unlock(&u->readlock); 847 out: 848 return err; 849 850 out_mknod_dput: 851 dput(dentry); 852 out_mknod_unlock: 853 mutex_unlock(&nd.dentry->d_inode->i_mutex); 854 path_release(&nd); 855 out_mknod_parent: 856 if (err==-EEXIST) 857 err=-EADDRINUSE; 858 unix_release_addr(addr); 859 goto out_up; 860 } 861 862 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 863 int alen, int flags) 864 { 865 struct sock *sk = sock->sk; 866 struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr; 867 struct sock *other; 868 unsigned hash; 869 int err; 870 871 if (addr->sa_family != AF_UNSPEC) { 872 err = unix_mkname(sunaddr, alen, &hash); 873 if (err < 0) 874 goto out; 875 alen = err; 876 877 if (test_bit(SOCK_PASSCRED, &sock->flags) && 878 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 879 goto out; 880 881 other=unix_find_other(sunaddr, alen, sock->type, hash, &err); 882 if (!other) 883 goto out; 884 885 unix_state_wlock(sk); 886 887 err = -EPERM; 888 if (!unix_may_send(sk, other)) 889 goto out_unlock; 890 891 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 892 if (err) 893 goto out_unlock; 894 895 } else { 896 /* 897 * 1003.1g breaking connected state with AF_UNSPEC 898 */ 899 other = NULL; 900 unix_state_wlock(sk); 901 } 902 903 /* 904 * If it was connected, reconnect. 905 */ 906 if (unix_peer(sk)) { 907 struct sock *old_peer = unix_peer(sk); 908 unix_peer(sk)=other; 909 unix_state_wunlock(sk); 910 911 if (other != old_peer) 912 unix_dgram_disconnected(sk, old_peer); 913 sock_put(old_peer); 914 } else { 915 unix_peer(sk)=other; 916 unix_state_wunlock(sk); 917 } 918 return 0; 919 920 out_unlock: 921 unix_state_wunlock(sk); 922 sock_put(other); 923 out: 924 return err; 925 } 926 927 static long unix_wait_for_peer(struct sock *other, long timeo) 928 { 929 struct unix_sock *u = unix_sk(other); 930 int sched; 931 DEFINE_WAIT(wait); 932 933 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 934 935 sched = !sock_flag(other, SOCK_DEAD) && 936 !(other->sk_shutdown & RCV_SHUTDOWN) && 937 (skb_queue_len(&other->sk_receive_queue) > 938 other->sk_max_ack_backlog); 939 940 unix_state_runlock(other); 941 942 if (sched) 943 timeo = schedule_timeout(timeo); 944 945 finish_wait(&u->peer_wait, &wait); 946 return timeo; 947 } 948 949 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 950 int addr_len, int flags) 951 { 952 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 953 struct sock *sk = sock->sk; 954 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 955 struct sock *newsk = NULL; 956 struct sock *other = NULL; 957 struct sk_buff *skb = NULL; 958 unsigned hash; 959 int st; 960 int err; 961 long timeo; 962 963 err = unix_mkname(sunaddr, addr_len, &hash); 964 if (err < 0) 965 goto out; 966 addr_len = err; 967 968 if (test_bit(SOCK_PASSCRED, &sock->flags) 969 && !u->addr && (err = unix_autobind(sock)) != 0) 970 goto out; 971 972 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 973 974 /* First of all allocate resources. 975 If we will make it after state is locked, 976 we will have to recheck all again in any case. 977 */ 978 979 err = -ENOMEM; 980 981 /* create new sock for complete connection */ 982 newsk = unix_create1(NULL); 983 if (newsk == NULL) 984 goto out; 985 986 /* Allocate skb for sending to listening sock */ 987 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 988 if (skb == NULL) 989 goto out; 990 991 restart: 992 /* Find listening sock. */ 993 other = unix_find_other(sunaddr, addr_len, sk->sk_type, hash, &err); 994 if (!other) 995 goto out; 996 997 /* Latch state of peer */ 998 unix_state_rlock(other); 999 1000 /* Apparently VFS overslept socket death. Retry. */ 1001 if (sock_flag(other, SOCK_DEAD)) { 1002 unix_state_runlock(other); 1003 sock_put(other); 1004 goto restart; 1005 } 1006 1007 err = -ECONNREFUSED; 1008 if (other->sk_state != TCP_LISTEN) 1009 goto out_unlock; 1010 1011 if (skb_queue_len(&other->sk_receive_queue) > 1012 other->sk_max_ack_backlog) { 1013 err = -EAGAIN; 1014 if (!timeo) 1015 goto out_unlock; 1016 1017 timeo = unix_wait_for_peer(other, timeo); 1018 1019 err = sock_intr_errno(timeo); 1020 if (signal_pending(current)) 1021 goto out; 1022 sock_put(other); 1023 goto restart; 1024 } 1025 1026 /* Latch our state. 1027 1028 It is tricky place. We need to grab write lock and cannot 1029 drop lock on peer. It is dangerous because deadlock is 1030 possible. Connect to self case and simultaneous 1031 attempt to connect are eliminated by checking socket 1032 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1033 check this before attempt to grab lock. 1034 1035 Well, and we have to recheck the state after socket locked. 1036 */ 1037 st = sk->sk_state; 1038 1039 switch (st) { 1040 case TCP_CLOSE: 1041 /* This is ok... continue with connect */ 1042 break; 1043 case TCP_ESTABLISHED: 1044 /* Socket is already connected */ 1045 err = -EISCONN; 1046 goto out_unlock; 1047 default: 1048 err = -EINVAL; 1049 goto out_unlock; 1050 } 1051 1052 unix_state_wlock_nested(sk); 1053 1054 if (sk->sk_state != st) { 1055 unix_state_wunlock(sk); 1056 unix_state_runlock(other); 1057 sock_put(other); 1058 goto restart; 1059 } 1060 1061 err = security_unix_stream_connect(sock, other->sk_socket, newsk); 1062 if (err) { 1063 unix_state_wunlock(sk); 1064 goto out_unlock; 1065 } 1066 1067 /* The way is open! Fastly set all the necessary fields... */ 1068 1069 sock_hold(sk); 1070 unix_peer(newsk) = sk; 1071 newsk->sk_state = TCP_ESTABLISHED; 1072 newsk->sk_type = sk->sk_type; 1073 newsk->sk_peercred.pid = current->tgid; 1074 newsk->sk_peercred.uid = current->euid; 1075 newsk->sk_peercred.gid = current->egid; 1076 newu = unix_sk(newsk); 1077 newsk->sk_sleep = &newu->peer_wait; 1078 otheru = unix_sk(other); 1079 1080 /* copy address information from listening to new sock*/ 1081 if (otheru->addr) { 1082 atomic_inc(&otheru->addr->refcnt); 1083 newu->addr = otheru->addr; 1084 } 1085 if (otheru->dentry) { 1086 newu->dentry = dget(otheru->dentry); 1087 newu->mnt = mntget(otheru->mnt); 1088 } 1089 1090 /* Set credentials */ 1091 sk->sk_peercred = other->sk_peercred; 1092 1093 sock->state = SS_CONNECTED; 1094 sk->sk_state = TCP_ESTABLISHED; 1095 sock_hold(newsk); 1096 1097 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1098 unix_peer(sk) = newsk; 1099 1100 unix_state_wunlock(sk); 1101 1102 /* take ten and and send info to listening sock */ 1103 spin_lock(&other->sk_receive_queue.lock); 1104 __skb_queue_tail(&other->sk_receive_queue, skb); 1105 /* Undo artificially decreased inflight after embrion 1106 * is installed to listening socket. */ 1107 atomic_inc(&newu->inflight); 1108 spin_unlock(&other->sk_receive_queue.lock); 1109 unix_state_runlock(other); 1110 other->sk_data_ready(other, 0); 1111 sock_put(other); 1112 return 0; 1113 1114 out_unlock: 1115 if (other) 1116 unix_state_runlock(other); 1117 1118 out: 1119 if (skb) 1120 kfree_skb(skb); 1121 if (newsk) 1122 unix_release_sock(newsk, 0); 1123 if (other) 1124 sock_put(other); 1125 return err; 1126 } 1127 1128 static int unix_socketpair(struct socket *socka, struct socket *sockb) 1129 { 1130 struct sock *ska=socka->sk, *skb = sockb->sk; 1131 1132 /* Join our sockets back to back */ 1133 sock_hold(ska); 1134 sock_hold(skb); 1135 unix_peer(ska)=skb; 1136 unix_peer(skb)=ska; 1137 ska->sk_peercred.pid = skb->sk_peercred.pid = current->tgid; 1138 ska->sk_peercred.uid = skb->sk_peercred.uid = current->euid; 1139 ska->sk_peercred.gid = skb->sk_peercred.gid = current->egid; 1140 1141 if (ska->sk_type != SOCK_DGRAM) { 1142 ska->sk_state = TCP_ESTABLISHED; 1143 skb->sk_state = TCP_ESTABLISHED; 1144 socka->state = SS_CONNECTED; 1145 sockb->state = SS_CONNECTED; 1146 } 1147 return 0; 1148 } 1149 1150 static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1151 { 1152 struct sock *sk = sock->sk; 1153 struct sock *tsk; 1154 struct sk_buff *skb; 1155 int err; 1156 1157 err = -EOPNOTSUPP; 1158 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET) 1159 goto out; 1160 1161 err = -EINVAL; 1162 if (sk->sk_state != TCP_LISTEN) 1163 goto out; 1164 1165 /* If socket state is TCP_LISTEN it cannot change (for now...), 1166 * so that no locks are necessary. 1167 */ 1168 1169 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1170 if (!skb) { 1171 /* This means receive shutdown. */ 1172 if (err == 0) 1173 err = -EINVAL; 1174 goto out; 1175 } 1176 1177 tsk = skb->sk; 1178 skb_free_datagram(sk, skb); 1179 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1180 1181 /* attach accepted sock to socket */ 1182 unix_state_wlock(tsk); 1183 newsock->state = SS_CONNECTED; 1184 sock_graft(tsk, newsock); 1185 unix_state_wunlock(tsk); 1186 return 0; 1187 1188 out: 1189 return err; 1190 } 1191 1192 1193 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1194 { 1195 struct sock *sk = sock->sk; 1196 struct unix_sock *u; 1197 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 1198 int err = 0; 1199 1200 if (peer) { 1201 sk = unix_peer_get(sk); 1202 1203 err = -ENOTCONN; 1204 if (!sk) 1205 goto out; 1206 err = 0; 1207 } else { 1208 sock_hold(sk); 1209 } 1210 1211 u = unix_sk(sk); 1212 unix_state_rlock(sk); 1213 if (!u->addr) { 1214 sunaddr->sun_family = AF_UNIX; 1215 sunaddr->sun_path[0] = 0; 1216 *uaddr_len = sizeof(short); 1217 } else { 1218 struct unix_address *addr = u->addr; 1219 1220 *uaddr_len = addr->len; 1221 memcpy(sunaddr, addr->name, *uaddr_len); 1222 } 1223 unix_state_runlock(sk); 1224 sock_put(sk); 1225 out: 1226 return err; 1227 } 1228 1229 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1230 { 1231 int i; 1232 1233 scm->fp = UNIXCB(skb).fp; 1234 skb->destructor = sock_wfree; 1235 UNIXCB(skb).fp = NULL; 1236 1237 for (i=scm->fp->count-1; i>=0; i--) 1238 unix_notinflight(scm->fp->fp[i]); 1239 } 1240 1241 static void unix_destruct_fds(struct sk_buff *skb) 1242 { 1243 struct scm_cookie scm; 1244 memset(&scm, 0, sizeof(scm)); 1245 unix_detach_fds(&scm, skb); 1246 1247 /* Alas, it calls VFS */ 1248 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1249 scm_destroy(&scm); 1250 sock_wfree(skb); 1251 } 1252 1253 static void unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1254 { 1255 int i; 1256 for (i=scm->fp->count-1; i>=0; i--) 1257 unix_inflight(scm->fp->fp[i]); 1258 UNIXCB(skb).fp = scm->fp; 1259 skb->destructor = unix_destruct_fds; 1260 scm->fp = NULL; 1261 } 1262 1263 /* 1264 * Send AF_UNIX data. 1265 */ 1266 1267 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1268 struct msghdr *msg, size_t len) 1269 { 1270 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1271 struct sock *sk = sock->sk; 1272 struct unix_sock *u = unix_sk(sk); 1273 struct sockaddr_un *sunaddr=msg->msg_name; 1274 struct sock *other = NULL; 1275 int namelen = 0; /* fake GCC */ 1276 int err; 1277 unsigned hash; 1278 struct sk_buff *skb; 1279 long timeo; 1280 struct scm_cookie tmp_scm; 1281 1282 if (NULL == siocb->scm) 1283 siocb->scm = &tmp_scm; 1284 err = scm_send(sock, msg, siocb->scm); 1285 if (err < 0) 1286 return err; 1287 1288 err = -EOPNOTSUPP; 1289 if (msg->msg_flags&MSG_OOB) 1290 goto out; 1291 1292 if (msg->msg_namelen) { 1293 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1294 if (err < 0) 1295 goto out; 1296 namelen = err; 1297 } else { 1298 sunaddr = NULL; 1299 err = -ENOTCONN; 1300 other = unix_peer_get(sk); 1301 if (!other) 1302 goto out; 1303 } 1304 1305 if (test_bit(SOCK_PASSCRED, &sock->flags) 1306 && !u->addr && (err = unix_autobind(sock)) != 0) 1307 goto out; 1308 1309 err = -EMSGSIZE; 1310 if (len > sk->sk_sndbuf - 32) 1311 goto out; 1312 1313 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err); 1314 if (skb==NULL) 1315 goto out; 1316 1317 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1318 if (siocb->scm->fp) 1319 unix_attach_fds(siocb->scm, skb); 1320 unix_get_secdata(siocb->scm, skb); 1321 1322 skb->h.raw = skb->data; 1323 err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len); 1324 if (err) 1325 goto out_free; 1326 1327 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1328 1329 restart: 1330 if (!other) { 1331 err = -ECONNRESET; 1332 if (sunaddr == NULL) 1333 goto out_free; 1334 1335 other = unix_find_other(sunaddr, namelen, sk->sk_type, 1336 hash, &err); 1337 if (other==NULL) 1338 goto out_free; 1339 } 1340 1341 unix_state_rlock(other); 1342 err = -EPERM; 1343 if (!unix_may_send(sk, other)) 1344 goto out_unlock; 1345 1346 if (sock_flag(other, SOCK_DEAD)) { 1347 /* 1348 * Check with 1003.1g - what should 1349 * datagram error 1350 */ 1351 unix_state_runlock(other); 1352 sock_put(other); 1353 1354 err = 0; 1355 unix_state_wlock(sk); 1356 if (unix_peer(sk) == other) { 1357 unix_peer(sk)=NULL; 1358 unix_state_wunlock(sk); 1359 1360 unix_dgram_disconnected(sk, other); 1361 sock_put(other); 1362 err = -ECONNREFUSED; 1363 } else { 1364 unix_state_wunlock(sk); 1365 } 1366 1367 other = NULL; 1368 if (err) 1369 goto out_free; 1370 goto restart; 1371 } 1372 1373 err = -EPIPE; 1374 if (other->sk_shutdown & RCV_SHUTDOWN) 1375 goto out_unlock; 1376 1377 if (sk->sk_type != SOCK_SEQPACKET) { 1378 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1379 if (err) 1380 goto out_unlock; 1381 } 1382 1383 if (unix_peer(other) != sk && 1384 (skb_queue_len(&other->sk_receive_queue) > 1385 other->sk_max_ack_backlog)) { 1386 if (!timeo) { 1387 err = -EAGAIN; 1388 goto out_unlock; 1389 } 1390 1391 timeo = unix_wait_for_peer(other, timeo); 1392 1393 err = sock_intr_errno(timeo); 1394 if (signal_pending(current)) 1395 goto out_free; 1396 1397 goto restart; 1398 } 1399 1400 skb_queue_tail(&other->sk_receive_queue, skb); 1401 unix_state_runlock(other); 1402 other->sk_data_ready(other, len); 1403 sock_put(other); 1404 scm_destroy(siocb->scm); 1405 return len; 1406 1407 out_unlock: 1408 unix_state_runlock(other); 1409 out_free: 1410 kfree_skb(skb); 1411 out: 1412 if (other) 1413 sock_put(other); 1414 scm_destroy(siocb->scm); 1415 return err; 1416 } 1417 1418 1419 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1420 struct msghdr *msg, size_t len) 1421 { 1422 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1423 struct sock *sk = sock->sk; 1424 struct sock *other = NULL; 1425 struct sockaddr_un *sunaddr=msg->msg_name; 1426 int err,size; 1427 struct sk_buff *skb; 1428 int sent=0; 1429 struct scm_cookie tmp_scm; 1430 1431 if (NULL == siocb->scm) 1432 siocb->scm = &tmp_scm; 1433 err = scm_send(sock, msg, siocb->scm); 1434 if (err < 0) 1435 return err; 1436 1437 err = -EOPNOTSUPP; 1438 if (msg->msg_flags&MSG_OOB) 1439 goto out_err; 1440 1441 if (msg->msg_namelen) { 1442 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1443 goto out_err; 1444 } else { 1445 sunaddr = NULL; 1446 err = -ENOTCONN; 1447 other = unix_peer(sk); 1448 if (!other) 1449 goto out_err; 1450 } 1451 1452 if (sk->sk_shutdown & SEND_SHUTDOWN) 1453 goto pipe_err; 1454 1455 while(sent < len) 1456 { 1457 /* 1458 * Optimisation for the fact that under 0.01% of X 1459 * messages typically need breaking up. 1460 */ 1461 1462 size = len-sent; 1463 1464 /* Keep two messages in the pipe so it schedules better */ 1465 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1466 size = (sk->sk_sndbuf >> 1) - 64; 1467 1468 if (size > SKB_MAX_ALLOC) 1469 size = SKB_MAX_ALLOC; 1470 1471 /* 1472 * Grab a buffer 1473 */ 1474 1475 skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err); 1476 1477 if (skb==NULL) 1478 goto out_err; 1479 1480 /* 1481 * If you pass two values to the sock_alloc_send_skb 1482 * it tries to grab the large buffer with GFP_NOFS 1483 * (which can fail easily), and if it fails grab the 1484 * fallback size buffer which is under a page and will 1485 * succeed. [Alan] 1486 */ 1487 size = min_t(int, size, skb_tailroom(skb)); 1488 1489 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1490 if (siocb->scm->fp) 1491 unix_attach_fds(siocb->scm, skb); 1492 1493 if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) { 1494 kfree_skb(skb); 1495 goto out_err; 1496 } 1497 1498 unix_state_rlock(other); 1499 1500 if (sock_flag(other, SOCK_DEAD) || 1501 (other->sk_shutdown & RCV_SHUTDOWN)) 1502 goto pipe_err_free; 1503 1504 skb_queue_tail(&other->sk_receive_queue, skb); 1505 unix_state_runlock(other); 1506 other->sk_data_ready(other, size); 1507 sent+=size; 1508 } 1509 1510 scm_destroy(siocb->scm); 1511 siocb->scm = NULL; 1512 1513 return sent; 1514 1515 pipe_err_free: 1516 unix_state_runlock(other); 1517 kfree_skb(skb); 1518 pipe_err: 1519 if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1520 send_sig(SIGPIPE,current,0); 1521 err = -EPIPE; 1522 out_err: 1523 scm_destroy(siocb->scm); 1524 siocb->scm = NULL; 1525 return sent ? : err; 1526 } 1527 1528 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1529 struct msghdr *msg, size_t len) 1530 { 1531 int err; 1532 struct sock *sk = sock->sk; 1533 1534 err = sock_error(sk); 1535 if (err) 1536 return err; 1537 1538 if (sk->sk_state != TCP_ESTABLISHED) 1539 return -ENOTCONN; 1540 1541 if (msg->msg_namelen) 1542 msg->msg_namelen = 0; 1543 1544 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1545 } 1546 1547 static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1548 { 1549 struct unix_sock *u = unix_sk(sk); 1550 1551 msg->msg_namelen = 0; 1552 if (u->addr) { 1553 msg->msg_namelen = u->addr->len; 1554 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1555 } 1556 } 1557 1558 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1559 struct msghdr *msg, size_t size, 1560 int flags) 1561 { 1562 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1563 struct scm_cookie tmp_scm; 1564 struct sock *sk = sock->sk; 1565 struct unix_sock *u = unix_sk(sk); 1566 int noblock = flags & MSG_DONTWAIT; 1567 struct sk_buff *skb; 1568 int err; 1569 1570 err = -EOPNOTSUPP; 1571 if (flags&MSG_OOB) 1572 goto out; 1573 1574 msg->msg_namelen = 0; 1575 1576 mutex_lock(&u->readlock); 1577 1578 skb = skb_recv_datagram(sk, flags, noblock, &err); 1579 if (!skb) 1580 goto out_unlock; 1581 1582 wake_up_interruptible(&u->peer_wait); 1583 1584 if (msg->msg_name) 1585 unix_copy_addr(msg, skb->sk); 1586 1587 if (size > skb->len) 1588 size = skb->len; 1589 else if (size < skb->len) 1590 msg->msg_flags |= MSG_TRUNC; 1591 1592 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size); 1593 if (err) 1594 goto out_free; 1595 1596 if (!siocb->scm) { 1597 siocb->scm = &tmp_scm; 1598 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1599 } 1600 siocb->scm->creds = *UNIXCREDS(skb); 1601 unix_set_secdata(siocb->scm, skb); 1602 1603 if (!(flags & MSG_PEEK)) 1604 { 1605 if (UNIXCB(skb).fp) 1606 unix_detach_fds(siocb->scm, skb); 1607 } 1608 else 1609 { 1610 /* It is questionable: on PEEK we could: 1611 - do not return fds - good, but too simple 8) 1612 - return fds, and do not return them on read (old strategy, 1613 apparently wrong) 1614 - clone fds (I chose it for now, it is the most universal 1615 solution) 1616 1617 POSIX 1003.1g does not actually define this clearly 1618 at all. POSIX 1003.1g doesn't define a lot of things 1619 clearly however! 1620 1621 */ 1622 if (UNIXCB(skb).fp) 1623 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1624 } 1625 err = size; 1626 1627 scm_recv(sock, msg, siocb->scm, flags); 1628 1629 out_free: 1630 skb_free_datagram(sk,skb); 1631 out_unlock: 1632 mutex_unlock(&u->readlock); 1633 out: 1634 return err; 1635 } 1636 1637 /* 1638 * Sleep until data has arrive. But check for races.. 1639 */ 1640 1641 static long unix_stream_data_wait(struct sock * sk, long timeo) 1642 { 1643 DEFINE_WAIT(wait); 1644 1645 unix_state_rlock(sk); 1646 1647 for (;;) { 1648 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); 1649 1650 if (!skb_queue_empty(&sk->sk_receive_queue) || 1651 sk->sk_err || 1652 (sk->sk_shutdown & RCV_SHUTDOWN) || 1653 signal_pending(current) || 1654 !timeo) 1655 break; 1656 1657 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1658 unix_state_runlock(sk); 1659 timeo = schedule_timeout(timeo); 1660 unix_state_rlock(sk); 1661 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1662 } 1663 1664 finish_wait(sk->sk_sleep, &wait); 1665 unix_state_runlock(sk); 1666 return timeo; 1667 } 1668 1669 1670 1671 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1672 struct msghdr *msg, size_t size, 1673 int flags) 1674 { 1675 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1676 struct scm_cookie tmp_scm; 1677 struct sock *sk = sock->sk; 1678 struct unix_sock *u = unix_sk(sk); 1679 struct sockaddr_un *sunaddr=msg->msg_name; 1680 int copied = 0; 1681 int check_creds = 0; 1682 int target; 1683 int err = 0; 1684 long timeo; 1685 1686 err = -EINVAL; 1687 if (sk->sk_state != TCP_ESTABLISHED) 1688 goto out; 1689 1690 err = -EOPNOTSUPP; 1691 if (flags&MSG_OOB) 1692 goto out; 1693 1694 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1695 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1696 1697 msg->msg_namelen = 0; 1698 1699 /* Lock the socket to prevent queue disordering 1700 * while sleeps in memcpy_tomsg 1701 */ 1702 1703 if (!siocb->scm) { 1704 siocb->scm = &tmp_scm; 1705 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1706 } 1707 1708 mutex_lock(&u->readlock); 1709 1710 do 1711 { 1712 int chunk; 1713 struct sk_buff *skb; 1714 1715 skb = skb_dequeue(&sk->sk_receive_queue); 1716 if (skb==NULL) 1717 { 1718 if (copied >= target) 1719 break; 1720 1721 /* 1722 * POSIX 1003.1g mandates this order. 1723 */ 1724 1725 if ((err = sock_error(sk)) != 0) 1726 break; 1727 if (sk->sk_shutdown & RCV_SHUTDOWN) 1728 break; 1729 err = -EAGAIN; 1730 if (!timeo) 1731 break; 1732 mutex_unlock(&u->readlock); 1733 1734 timeo = unix_stream_data_wait(sk, timeo); 1735 1736 if (signal_pending(current)) { 1737 err = sock_intr_errno(timeo); 1738 goto out; 1739 } 1740 mutex_lock(&u->readlock); 1741 continue; 1742 } 1743 1744 if (check_creds) { 1745 /* Never glue messages from different writers */ 1746 if (memcmp(UNIXCREDS(skb), &siocb->scm->creds, sizeof(siocb->scm->creds)) != 0) { 1747 skb_queue_head(&sk->sk_receive_queue, skb); 1748 break; 1749 } 1750 } else { 1751 /* Copy credentials */ 1752 siocb->scm->creds = *UNIXCREDS(skb); 1753 check_creds = 1; 1754 } 1755 1756 /* Copy address just once */ 1757 if (sunaddr) 1758 { 1759 unix_copy_addr(msg, skb->sk); 1760 sunaddr = NULL; 1761 } 1762 1763 chunk = min_t(unsigned int, skb->len, size); 1764 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) { 1765 skb_queue_head(&sk->sk_receive_queue, skb); 1766 if (copied == 0) 1767 copied = -EFAULT; 1768 break; 1769 } 1770 copied += chunk; 1771 size -= chunk; 1772 1773 /* Mark read part of skb as used */ 1774 if (!(flags & MSG_PEEK)) 1775 { 1776 skb_pull(skb, chunk); 1777 1778 if (UNIXCB(skb).fp) 1779 unix_detach_fds(siocb->scm, skb); 1780 1781 /* put the skb back if we didn't use it up.. */ 1782 if (skb->len) 1783 { 1784 skb_queue_head(&sk->sk_receive_queue, skb); 1785 break; 1786 } 1787 1788 kfree_skb(skb); 1789 1790 if (siocb->scm->fp) 1791 break; 1792 } 1793 else 1794 { 1795 /* It is questionable, see note in unix_dgram_recvmsg. 1796 */ 1797 if (UNIXCB(skb).fp) 1798 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1799 1800 /* put message back and return */ 1801 skb_queue_head(&sk->sk_receive_queue, skb); 1802 break; 1803 } 1804 } while (size); 1805 1806 mutex_unlock(&u->readlock); 1807 scm_recv(sock, msg, siocb->scm, flags); 1808 out: 1809 return copied ? : err; 1810 } 1811 1812 static int unix_shutdown(struct socket *sock, int mode) 1813 { 1814 struct sock *sk = sock->sk; 1815 struct sock *other; 1816 1817 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN); 1818 1819 if (mode) { 1820 unix_state_wlock(sk); 1821 sk->sk_shutdown |= mode; 1822 other=unix_peer(sk); 1823 if (other) 1824 sock_hold(other); 1825 unix_state_wunlock(sk); 1826 sk->sk_state_change(sk); 1827 1828 if (other && 1829 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 1830 1831 int peer_mode = 0; 1832 1833 if (mode&RCV_SHUTDOWN) 1834 peer_mode |= SEND_SHUTDOWN; 1835 if (mode&SEND_SHUTDOWN) 1836 peer_mode |= RCV_SHUTDOWN; 1837 unix_state_wlock(other); 1838 other->sk_shutdown |= peer_mode; 1839 unix_state_wunlock(other); 1840 other->sk_state_change(other); 1841 read_lock(&other->sk_callback_lock); 1842 if (peer_mode == SHUTDOWN_MASK) 1843 sk_wake_async(other,1,POLL_HUP); 1844 else if (peer_mode & RCV_SHUTDOWN) 1845 sk_wake_async(other,1,POLL_IN); 1846 read_unlock(&other->sk_callback_lock); 1847 } 1848 if (other) 1849 sock_put(other); 1850 } 1851 return 0; 1852 } 1853 1854 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 1855 { 1856 struct sock *sk = sock->sk; 1857 long amount=0; 1858 int err; 1859 1860 switch(cmd) 1861 { 1862 case SIOCOUTQ: 1863 amount = atomic_read(&sk->sk_wmem_alloc); 1864 err = put_user(amount, (int __user *)arg); 1865 break; 1866 case SIOCINQ: 1867 { 1868 struct sk_buff *skb; 1869 1870 if (sk->sk_state == TCP_LISTEN) { 1871 err = -EINVAL; 1872 break; 1873 } 1874 1875 spin_lock(&sk->sk_receive_queue.lock); 1876 if (sk->sk_type == SOCK_STREAM || 1877 sk->sk_type == SOCK_SEQPACKET) { 1878 skb_queue_walk(&sk->sk_receive_queue, skb) 1879 amount += skb->len; 1880 } else { 1881 skb = skb_peek(&sk->sk_receive_queue); 1882 if (skb) 1883 amount=skb->len; 1884 } 1885 spin_unlock(&sk->sk_receive_queue.lock); 1886 err = put_user(amount, (int __user *)arg); 1887 break; 1888 } 1889 1890 default: 1891 err = -ENOIOCTLCMD; 1892 break; 1893 } 1894 return err; 1895 } 1896 1897 static unsigned int unix_poll(struct file * file, struct socket *sock, poll_table *wait) 1898 { 1899 struct sock *sk = sock->sk; 1900 unsigned int mask; 1901 1902 poll_wait(file, sk->sk_sleep, wait); 1903 mask = 0; 1904 1905 /* exceptional events? */ 1906 if (sk->sk_err) 1907 mask |= POLLERR; 1908 if (sk->sk_shutdown == SHUTDOWN_MASK) 1909 mask |= POLLHUP; 1910 if (sk->sk_shutdown & RCV_SHUTDOWN) 1911 mask |= POLLRDHUP; 1912 1913 /* readable? */ 1914 if (!skb_queue_empty(&sk->sk_receive_queue) || 1915 (sk->sk_shutdown & RCV_SHUTDOWN)) 1916 mask |= POLLIN | POLLRDNORM; 1917 1918 /* Connection-based need to check for termination and startup */ 1919 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && sk->sk_state == TCP_CLOSE) 1920 mask |= POLLHUP; 1921 1922 /* 1923 * we set writable also when the other side has shut down the 1924 * connection. This prevents stuck sockets. 1925 */ 1926 if (unix_writable(sk)) 1927 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 1928 1929 return mask; 1930 } 1931 1932 1933 #ifdef CONFIG_PROC_FS 1934 static struct sock *unix_seq_idx(int *iter, loff_t pos) 1935 { 1936 loff_t off = 0; 1937 struct sock *s; 1938 1939 for (s = first_unix_socket(iter); s; s = next_unix_socket(iter, s)) { 1940 if (off == pos) 1941 return s; 1942 ++off; 1943 } 1944 return NULL; 1945 } 1946 1947 1948 static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 1949 { 1950 spin_lock(&unix_table_lock); 1951 return *pos ? unix_seq_idx(seq->private, *pos - 1) : ((void *) 1); 1952 } 1953 1954 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1955 { 1956 ++*pos; 1957 1958 if (v == (void *)1) 1959 return first_unix_socket(seq->private); 1960 return next_unix_socket(seq->private, v); 1961 } 1962 1963 static void unix_seq_stop(struct seq_file *seq, void *v) 1964 { 1965 spin_unlock(&unix_table_lock); 1966 } 1967 1968 static int unix_seq_show(struct seq_file *seq, void *v) 1969 { 1970 1971 if (v == (void *)1) 1972 seq_puts(seq, "Num RefCount Protocol Flags Type St " 1973 "Inode Path\n"); 1974 else { 1975 struct sock *s = v; 1976 struct unix_sock *u = unix_sk(s); 1977 unix_state_rlock(s); 1978 1979 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu", 1980 s, 1981 atomic_read(&s->sk_refcnt), 1982 0, 1983 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 1984 s->sk_type, 1985 s->sk_socket ? 1986 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 1987 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 1988 sock_i_ino(s)); 1989 1990 if (u->addr) { 1991 int i, len; 1992 seq_putc(seq, ' '); 1993 1994 i = 0; 1995 len = u->addr->len - sizeof(short); 1996 if (!UNIX_ABSTRACT(s)) 1997 len--; 1998 else { 1999 seq_putc(seq, '@'); 2000 i++; 2001 } 2002 for ( ; i < len; i++) 2003 seq_putc(seq, u->addr->name->sun_path[i]); 2004 } 2005 unix_state_runlock(s); 2006 seq_putc(seq, '\n'); 2007 } 2008 2009 return 0; 2010 } 2011 2012 static struct seq_operations unix_seq_ops = { 2013 .start = unix_seq_start, 2014 .next = unix_seq_next, 2015 .stop = unix_seq_stop, 2016 .show = unix_seq_show, 2017 }; 2018 2019 2020 static int unix_seq_open(struct inode *inode, struct file *file) 2021 { 2022 struct seq_file *seq; 2023 int rc = -ENOMEM; 2024 int *iter = kmalloc(sizeof(int), GFP_KERNEL); 2025 2026 if (!iter) 2027 goto out; 2028 2029 rc = seq_open(file, &unix_seq_ops); 2030 if (rc) 2031 goto out_kfree; 2032 2033 seq = file->private_data; 2034 seq->private = iter; 2035 *iter = 0; 2036 out: 2037 return rc; 2038 out_kfree: 2039 kfree(iter); 2040 goto out; 2041 } 2042 2043 static struct file_operations unix_seq_fops = { 2044 .owner = THIS_MODULE, 2045 .open = unix_seq_open, 2046 .read = seq_read, 2047 .llseek = seq_lseek, 2048 .release = seq_release_private, 2049 }; 2050 2051 #endif 2052 2053 static struct net_proto_family unix_family_ops = { 2054 .family = PF_UNIX, 2055 .create = unix_create, 2056 .owner = THIS_MODULE, 2057 }; 2058 2059 static int __init af_unix_init(void) 2060 { 2061 int rc = -1; 2062 struct sk_buff *dummy_skb; 2063 2064 BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb)); 2065 2066 rc = proto_register(&unix_proto, 1); 2067 if (rc != 0) { 2068 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2069 __FUNCTION__); 2070 goto out; 2071 } 2072 2073 sock_register(&unix_family_ops); 2074 #ifdef CONFIG_PROC_FS 2075 proc_net_fops_create("unix", 0, &unix_seq_fops); 2076 #endif 2077 unix_sysctl_register(); 2078 out: 2079 return rc; 2080 } 2081 2082 static void __exit af_unix_exit(void) 2083 { 2084 sock_unregister(PF_UNIX); 2085 unix_sysctl_unregister(); 2086 proc_net_remove("unix"); 2087 proto_unregister(&unix_proto); 2088 } 2089 2090 module_init(af_unix_init); 2091 module_exit(af_unix_exit); 2092 2093 MODULE_LICENSE("GPL"); 2094 MODULE_ALIAS_NETPROTO(PF_UNIX); 2095