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/config.h> 87 #include <linux/kernel.h> 88 #include <linux/signal.h> 89 #include <linux/sched.h> 90 #include <linux/errno.h> 91 #include <linux/string.h> 92 #include <linux/stat.h> 93 #include <linux/dcache.h> 94 #include <linux/namei.h> 95 #include <linux/socket.h> 96 #include <linux/un.h> 97 #include <linux/fcntl.h> 98 #include <linux/termios.h> 99 #include <linux/sockios.h> 100 #include <linux/net.h> 101 #include <linux/in.h> 102 #include <linux/fs.h> 103 #include <linux/slab.h> 104 #include <asm/uaccess.h> 105 #include <linux/skbuff.h> 106 #include <linux/netdevice.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/smp_lock.h> 116 #include <linux/rtnetlink.h> 117 #include <linux/mount.h> 118 #include <net/checksum.h> 119 #include <linux/security.h> 120 121 int sysctl_unix_max_dgram_qlen = 10; 122 123 struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1]; 124 DEFINE_SPINLOCK(unix_table_lock); 125 static atomic_t unix_nr_socks = ATOMIC_INIT(0); 126 127 #define unix_sockets_unbound (&unix_socket_table[UNIX_HASH_SIZE]) 128 129 #define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE) 130 131 /* 132 * SMP locking strategy: 133 * hash table is protected with spinlock unix_table_lock 134 * each socket state is protected by separate rwlock. 135 */ 136 137 static inline unsigned unix_hash_fold(unsigned hash) 138 { 139 hash ^= hash>>16; 140 hash ^= hash>>8; 141 return hash&(UNIX_HASH_SIZE-1); 142 } 143 144 #define unix_peer(sk) (unix_sk(sk)->peer) 145 146 static inline int unix_our_peer(struct sock *sk, struct sock *osk) 147 { 148 return unix_peer(osk) == sk; 149 } 150 151 static inline int unix_may_send(struct sock *sk, struct sock *osk) 152 { 153 return (unix_peer(osk) == NULL || unix_our_peer(sk, osk)); 154 } 155 156 static struct sock *unix_peer_get(struct sock *s) 157 { 158 struct sock *peer; 159 160 unix_state_rlock(s); 161 peer = unix_peer(s); 162 if (peer) 163 sock_hold(peer); 164 unix_state_runlock(s); 165 return peer; 166 } 167 168 static inline void unix_release_addr(struct unix_address *addr) 169 { 170 if (atomic_dec_and_test(&addr->refcnt)) 171 kfree(addr); 172 } 173 174 /* 175 * Check unix socket name: 176 * - should be not zero length. 177 * - if started by not zero, should be NULL terminated (FS object) 178 * - if started by zero, it is abstract name. 179 */ 180 181 static int unix_mkname(struct sockaddr_un * sunaddr, int len, unsigned *hashp) 182 { 183 if (len <= sizeof(short) || len > sizeof(*sunaddr)) 184 return -EINVAL; 185 if (!sunaddr || sunaddr->sun_family != AF_UNIX) 186 return -EINVAL; 187 if (sunaddr->sun_path[0]) { 188 /* 189 * This may look like an off by one error but it is a bit more 190 * subtle. 108 is the longest valid AF_UNIX path for a binding. 191 * sun_path[108] doesnt as such exist. However in kernel space 192 * we are guaranteed that it is a valid memory location in our 193 * kernel address buffer. 194 */ 195 ((char *)sunaddr)[len]=0; 196 len = strlen(sunaddr->sun_path)+1+sizeof(short); 197 return len; 198 } 199 200 *hashp = unix_hash_fold(csum_partial((char*)sunaddr, len, 0)); 201 return len; 202 } 203 204 static void __unix_remove_socket(struct sock *sk) 205 { 206 sk_del_node_init(sk); 207 } 208 209 static void __unix_insert_socket(struct hlist_head *list, struct sock *sk) 210 { 211 BUG_TRAP(sk_unhashed(sk)); 212 sk_add_node(sk, list); 213 } 214 215 static inline void unix_remove_socket(struct sock *sk) 216 { 217 spin_lock(&unix_table_lock); 218 __unix_remove_socket(sk); 219 spin_unlock(&unix_table_lock); 220 } 221 222 static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 223 { 224 spin_lock(&unix_table_lock); 225 __unix_insert_socket(list, sk); 226 spin_unlock(&unix_table_lock); 227 } 228 229 static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname, 230 int len, int type, unsigned hash) 231 { 232 struct sock *s; 233 struct hlist_node *node; 234 235 sk_for_each(s, node, &unix_socket_table[hash ^ type]) { 236 struct unix_sock *u = unix_sk(s); 237 238 if (u->addr->len == len && 239 !memcmp(u->addr->name, sunname, len)) 240 goto found; 241 } 242 s = NULL; 243 found: 244 return s; 245 } 246 247 static inline struct sock *unix_find_socket_byname(struct sockaddr_un *sunname, 248 int len, int type, 249 unsigned hash) 250 { 251 struct sock *s; 252 253 spin_lock(&unix_table_lock); 254 s = __unix_find_socket_byname(sunname, len, type, hash); 255 if (s) 256 sock_hold(s); 257 spin_unlock(&unix_table_lock); 258 return s; 259 } 260 261 static struct sock *unix_find_socket_byinode(struct inode *i) 262 { 263 struct sock *s; 264 struct hlist_node *node; 265 266 spin_lock(&unix_table_lock); 267 sk_for_each(s, node, 268 &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) { 269 struct dentry *dentry = unix_sk(s)->dentry; 270 271 if(dentry && dentry->d_inode == i) 272 { 273 sock_hold(s); 274 goto found; 275 } 276 } 277 s = NULL; 278 found: 279 spin_unlock(&unix_table_lock); 280 return s; 281 } 282 283 static inline int unix_writable(struct sock *sk) 284 { 285 return (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; 286 } 287 288 static void unix_write_space(struct sock *sk) 289 { 290 read_lock(&sk->sk_callback_lock); 291 if (unix_writable(sk)) { 292 if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) 293 wake_up_interruptible(sk->sk_sleep); 294 sk_wake_async(sk, 2, POLL_OUT); 295 } 296 read_unlock(&sk->sk_callback_lock); 297 } 298 299 /* When dgram socket disconnects (or changes its peer), we clear its receive 300 * queue of packets arrived from previous peer. First, it allows to do 301 * flow control based only on wmem_alloc; second, sk connected to peer 302 * may receive messages only from that peer. */ 303 static void unix_dgram_disconnected(struct sock *sk, struct sock *other) 304 { 305 if (!skb_queue_empty(&sk->sk_receive_queue)) { 306 skb_queue_purge(&sk->sk_receive_queue); 307 wake_up_interruptible_all(&unix_sk(sk)->peer_wait); 308 309 /* If one link of bidirectional dgram pipe is disconnected, 310 * we signal error. Messages are lost. Do not make this, 311 * when peer was not connected to us. 312 */ 313 if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { 314 other->sk_err = ECONNRESET; 315 other->sk_error_report(other); 316 } 317 } 318 } 319 320 static void unix_sock_destructor(struct sock *sk) 321 { 322 struct unix_sock *u = unix_sk(sk); 323 324 skb_queue_purge(&sk->sk_receive_queue); 325 326 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc)); 327 BUG_TRAP(sk_unhashed(sk)); 328 BUG_TRAP(!sk->sk_socket); 329 if (!sock_flag(sk, SOCK_DEAD)) { 330 printk("Attempt to release alive unix socket: %p\n", sk); 331 return; 332 } 333 334 if (u->addr) 335 unix_release_addr(u->addr); 336 337 atomic_dec(&unix_nr_socks); 338 #ifdef UNIX_REFCNT_DEBUG 339 printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk, atomic_read(&unix_nr_socks)); 340 #endif 341 } 342 343 static int unix_release_sock (struct sock *sk, int embrion) 344 { 345 struct unix_sock *u = unix_sk(sk); 346 struct dentry *dentry; 347 struct vfsmount *mnt; 348 struct sock *skpair; 349 struct sk_buff *skb; 350 int state; 351 352 unix_remove_socket(sk); 353 354 /* Clear state */ 355 unix_state_wlock(sk); 356 sock_orphan(sk); 357 sk->sk_shutdown = SHUTDOWN_MASK; 358 dentry = u->dentry; 359 u->dentry = NULL; 360 mnt = u->mnt; 361 u->mnt = NULL; 362 state = sk->sk_state; 363 sk->sk_state = TCP_CLOSE; 364 unix_state_wunlock(sk); 365 366 wake_up_interruptible_all(&u->peer_wait); 367 368 skpair=unix_peer(sk); 369 370 if (skpair!=NULL) { 371 if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { 372 unix_state_wlock(skpair); 373 /* No more writes */ 374 skpair->sk_shutdown = SHUTDOWN_MASK; 375 if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) 376 skpair->sk_err = ECONNRESET; 377 unix_state_wunlock(skpair); 378 skpair->sk_state_change(skpair); 379 read_lock(&skpair->sk_callback_lock); 380 sk_wake_async(skpair,1,POLL_HUP); 381 read_unlock(&skpair->sk_callback_lock); 382 } 383 sock_put(skpair); /* It may now die */ 384 unix_peer(sk) = NULL; 385 } 386 387 /* Try to flush out this socket. Throw out buffers at least */ 388 389 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { 390 if (state==TCP_LISTEN) 391 unix_release_sock(skb->sk, 1); 392 /* passed fds are erased in the kfree_skb hook */ 393 kfree_skb(skb); 394 } 395 396 if (dentry) { 397 dput(dentry); 398 mntput(mnt); 399 } 400 401 sock_put(sk); 402 403 /* ---- Socket is dead now and most probably destroyed ---- */ 404 405 /* 406 * Fixme: BSD difference: In BSD all sockets connected to use get 407 * ECONNRESET and we die on the spot. In Linux we behave 408 * like files and pipes do and wait for the last 409 * dereference. 410 * 411 * Can't we simply set sock->err? 412 * 413 * What the above comment does talk about? --ANK(980817) 414 */ 415 416 if (atomic_read(&unix_tot_inflight)) 417 unix_gc(); /* Garbage collect fds */ 418 419 return 0; 420 } 421 422 static int unix_listen(struct socket *sock, int backlog) 423 { 424 int err; 425 struct sock *sk = sock->sk; 426 struct unix_sock *u = unix_sk(sk); 427 428 err = -EOPNOTSUPP; 429 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET) 430 goto out; /* Only stream/seqpacket sockets accept */ 431 err = -EINVAL; 432 if (!u->addr) 433 goto out; /* No listens on an unbound socket */ 434 unix_state_wlock(sk); 435 if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) 436 goto out_unlock; 437 if (backlog > sk->sk_max_ack_backlog) 438 wake_up_interruptible_all(&u->peer_wait); 439 sk->sk_max_ack_backlog = backlog; 440 sk->sk_state = TCP_LISTEN; 441 /* set credentials so connect can copy them */ 442 sk->sk_peercred.pid = current->tgid; 443 sk->sk_peercred.uid = current->euid; 444 sk->sk_peercred.gid = current->egid; 445 err = 0; 446 447 out_unlock: 448 unix_state_wunlock(sk); 449 out: 450 return err; 451 } 452 453 static int unix_release(struct socket *); 454 static int unix_bind(struct socket *, struct sockaddr *, int); 455 static int unix_stream_connect(struct socket *, struct sockaddr *, 456 int addr_len, int flags); 457 static int unix_socketpair(struct socket *, struct socket *); 458 static int unix_accept(struct socket *, struct socket *, int); 459 static int unix_getname(struct socket *, struct sockaddr *, int *, int); 460 static unsigned int unix_poll(struct file *, struct socket *, poll_table *); 461 static int unix_ioctl(struct socket *, unsigned int, unsigned long); 462 static int unix_shutdown(struct socket *, int); 463 static int unix_stream_sendmsg(struct kiocb *, struct socket *, 464 struct msghdr *, size_t); 465 static int unix_stream_recvmsg(struct kiocb *, struct socket *, 466 struct msghdr *, size_t, int); 467 static int unix_dgram_sendmsg(struct kiocb *, struct socket *, 468 struct msghdr *, size_t); 469 static int unix_dgram_recvmsg(struct kiocb *, struct socket *, 470 struct msghdr *, size_t, int); 471 static int unix_dgram_connect(struct socket *, struct sockaddr *, 472 int, int); 473 static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 474 struct msghdr *, size_t); 475 476 static const struct proto_ops unix_stream_ops = { 477 .family = PF_UNIX, 478 .owner = THIS_MODULE, 479 .release = unix_release, 480 .bind = unix_bind, 481 .connect = unix_stream_connect, 482 .socketpair = unix_socketpair, 483 .accept = unix_accept, 484 .getname = unix_getname, 485 .poll = unix_poll, 486 .ioctl = unix_ioctl, 487 .listen = unix_listen, 488 .shutdown = unix_shutdown, 489 .setsockopt = sock_no_setsockopt, 490 .getsockopt = sock_no_getsockopt, 491 .sendmsg = unix_stream_sendmsg, 492 .recvmsg = unix_stream_recvmsg, 493 .mmap = sock_no_mmap, 494 .sendpage = sock_no_sendpage, 495 }; 496 497 static const struct proto_ops unix_dgram_ops = { 498 .family = PF_UNIX, 499 .owner = THIS_MODULE, 500 .release = unix_release, 501 .bind = unix_bind, 502 .connect = unix_dgram_connect, 503 .socketpair = unix_socketpair, 504 .accept = sock_no_accept, 505 .getname = unix_getname, 506 .poll = datagram_poll, 507 .ioctl = unix_ioctl, 508 .listen = sock_no_listen, 509 .shutdown = unix_shutdown, 510 .setsockopt = sock_no_setsockopt, 511 .getsockopt = sock_no_getsockopt, 512 .sendmsg = unix_dgram_sendmsg, 513 .recvmsg = unix_dgram_recvmsg, 514 .mmap = sock_no_mmap, 515 .sendpage = sock_no_sendpage, 516 }; 517 518 static const struct proto_ops unix_seqpacket_ops = { 519 .family = PF_UNIX, 520 .owner = THIS_MODULE, 521 .release = unix_release, 522 .bind = unix_bind, 523 .connect = unix_stream_connect, 524 .socketpair = unix_socketpair, 525 .accept = unix_accept, 526 .getname = unix_getname, 527 .poll = datagram_poll, 528 .ioctl = unix_ioctl, 529 .listen = unix_listen, 530 .shutdown = unix_shutdown, 531 .setsockopt = sock_no_setsockopt, 532 .getsockopt = sock_no_getsockopt, 533 .sendmsg = unix_seqpacket_sendmsg, 534 .recvmsg = unix_dgram_recvmsg, 535 .mmap = sock_no_mmap, 536 .sendpage = sock_no_sendpage, 537 }; 538 539 static struct proto unix_proto = { 540 .name = "UNIX", 541 .owner = THIS_MODULE, 542 .obj_size = sizeof(struct unix_sock), 543 }; 544 545 static struct sock * unix_create1(struct socket *sock) 546 { 547 struct sock *sk = NULL; 548 struct unix_sock *u; 549 550 if (atomic_read(&unix_nr_socks) >= 2*get_max_files()) 551 goto out; 552 553 sk = sk_alloc(PF_UNIX, GFP_KERNEL, &unix_proto, 1); 554 if (!sk) 555 goto out; 556 557 atomic_inc(&unix_nr_socks); 558 559 sock_init_data(sock,sk); 560 561 sk->sk_write_space = unix_write_space; 562 sk->sk_max_ack_backlog = sysctl_unix_max_dgram_qlen; 563 sk->sk_destruct = unix_sock_destructor; 564 u = unix_sk(sk); 565 u->dentry = NULL; 566 u->mnt = NULL; 567 spin_lock_init(&u->lock); 568 atomic_set(&u->inflight, sock ? 0 : -1); 569 mutex_init(&u->readlock); /* single task reading lock */ 570 init_waitqueue_head(&u->peer_wait); 571 unix_insert_socket(unix_sockets_unbound, sk); 572 out: 573 return sk; 574 } 575 576 static int unix_create(struct socket *sock, int protocol) 577 { 578 if (protocol && protocol != PF_UNIX) 579 return -EPROTONOSUPPORT; 580 581 sock->state = SS_UNCONNECTED; 582 583 switch (sock->type) { 584 case SOCK_STREAM: 585 sock->ops = &unix_stream_ops; 586 break; 587 /* 588 * Believe it or not BSD has AF_UNIX, SOCK_RAW though 589 * nothing uses it. 590 */ 591 case SOCK_RAW: 592 sock->type=SOCK_DGRAM; 593 case SOCK_DGRAM: 594 sock->ops = &unix_dgram_ops; 595 break; 596 case SOCK_SEQPACKET: 597 sock->ops = &unix_seqpacket_ops; 598 break; 599 default: 600 return -ESOCKTNOSUPPORT; 601 } 602 603 return unix_create1(sock) ? 0 : -ENOMEM; 604 } 605 606 static int unix_release(struct socket *sock) 607 { 608 struct sock *sk = sock->sk; 609 610 if (!sk) 611 return 0; 612 613 sock->sk = NULL; 614 615 return unix_release_sock (sk, 0); 616 } 617 618 static int unix_autobind(struct socket *sock) 619 { 620 struct sock *sk = sock->sk; 621 struct unix_sock *u = unix_sk(sk); 622 static u32 ordernum = 1; 623 struct unix_address * addr; 624 int err; 625 626 mutex_lock(&u->readlock); 627 628 err = 0; 629 if (u->addr) 630 goto out; 631 632 err = -ENOMEM; 633 addr = kmalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL); 634 if (!addr) 635 goto out; 636 637 memset(addr, 0, sizeof(*addr) + sizeof(short) + 16); 638 addr->name->sun_family = AF_UNIX; 639 atomic_set(&addr->refcnt, 1); 640 641 retry: 642 addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short); 643 addr->hash = unix_hash_fold(csum_partial((void*)addr->name, addr->len, 0)); 644 645 spin_lock(&unix_table_lock); 646 ordernum = (ordernum+1)&0xFFFFF; 647 648 if (__unix_find_socket_byname(addr->name, addr->len, sock->type, 649 addr->hash)) { 650 spin_unlock(&unix_table_lock); 651 /* Sanity yield. It is unusual case, but yet... */ 652 if (!(ordernum&0xFF)) 653 yield(); 654 goto retry; 655 } 656 addr->hash ^= sk->sk_type; 657 658 __unix_remove_socket(sk); 659 u->addr = addr; 660 __unix_insert_socket(&unix_socket_table[addr->hash], sk); 661 spin_unlock(&unix_table_lock); 662 err = 0; 663 664 out: mutex_unlock(&u->readlock); 665 return err; 666 } 667 668 static struct sock *unix_find_other(struct sockaddr_un *sunname, int len, 669 int type, unsigned hash, int *error) 670 { 671 struct sock *u; 672 struct nameidata nd; 673 int err = 0; 674 675 if (sunname->sun_path[0]) { 676 err = path_lookup(sunname->sun_path, LOOKUP_FOLLOW, &nd); 677 if (err) 678 goto fail; 679 err = vfs_permission(&nd, MAY_WRITE); 680 if (err) 681 goto put_fail; 682 683 err = -ECONNREFUSED; 684 if (!S_ISSOCK(nd.dentry->d_inode->i_mode)) 685 goto put_fail; 686 u=unix_find_socket_byinode(nd.dentry->d_inode); 687 if (!u) 688 goto put_fail; 689 690 if (u->sk_type == type) 691 touch_atime(nd.mnt, nd.dentry); 692 693 path_release(&nd); 694 695 err=-EPROTOTYPE; 696 if (u->sk_type != type) { 697 sock_put(u); 698 goto fail; 699 } 700 } else { 701 err = -ECONNREFUSED; 702 u=unix_find_socket_byname(sunname, len, type, hash); 703 if (u) { 704 struct dentry *dentry; 705 dentry = unix_sk(u)->dentry; 706 if (dentry) 707 touch_atime(unix_sk(u)->mnt, dentry); 708 } else 709 goto fail; 710 } 711 return u; 712 713 put_fail: 714 path_release(&nd); 715 fail: 716 *error=err; 717 return NULL; 718 } 719 720 721 static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 722 { 723 struct sock *sk = sock->sk; 724 struct unix_sock *u = unix_sk(sk); 725 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 726 struct dentry * dentry = NULL; 727 struct nameidata nd; 728 int err; 729 unsigned hash; 730 struct unix_address *addr; 731 struct hlist_head *list; 732 733 err = -EINVAL; 734 if (sunaddr->sun_family != AF_UNIX) 735 goto out; 736 737 if (addr_len==sizeof(short)) { 738 err = unix_autobind(sock); 739 goto out; 740 } 741 742 err = unix_mkname(sunaddr, addr_len, &hash); 743 if (err < 0) 744 goto out; 745 addr_len = err; 746 747 mutex_lock(&u->readlock); 748 749 err = -EINVAL; 750 if (u->addr) 751 goto out_up; 752 753 err = -ENOMEM; 754 addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL); 755 if (!addr) 756 goto out_up; 757 758 memcpy(addr->name, sunaddr, addr_len); 759 addr->len = addr_len; 760 addr->hash = hash ^ sk->sk_type; 761 atomic_set(&addr->refcnt, 1); 762 763 if (sunaddr->sun_path[0]) { 764 unsigned int mode; 765 err = 0; 766 /* 767 * Get the parent directory, calculate the hash for last 768 * component. 769 */ 770 err = path_lookup(sunaddr->sun_path, LOOKUP_PARENT, &nd); 771 if (err) 772 goto out_mknod_parent; 773 774 dentry = lookup_create(&nd, 0); 775 err = PTR_ERR(dentry); 776 if (IS_ERR(dentry)) 777 goto out_mknod_unlock; 778 779 /* 780 * All right, let's create it. 781 */ 782 mode = S_IFSOCK | 783 (SOCK_INODE(sock)->i_mode & ~current->fs->umask); 784 err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0); 785 if (err) 786 goto out_mknod_dput; 787 mutex_unlock(&nd.dentry->d_inode->i_mutex); 788 dput(nd.dentry); 789 nd.dentry = dentry; 790 791 addr->hash = UNIX_HASH_SIZE; 792 } 793 794 spin_lock(&unix_table_lock); 795 796 if (!sunaddr->sun_path[0]) { 797 err = -EADDRINUSE; 798 if (__unix_find_socket_byname(sunaddr, addr_len, 799 sk->sk_type, hash)) { 800 unix_release_addr(addr); 801 goto out_unlock; 802 } 803 804 list = &unix_socket_table[addr->hash]; 805 } else { 806 list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)]; 807 u->dentry = nd.dentry; 808 u->mnt = nd.mnt; 809 } 810 811 err = 0; 812 __unix_remove_socket(sk); 813 u->addr = addr; 814 __unix_insert_socket(list, sk); 815 816 out_unlock: 817 spin_unlock(&unix_table_lock); 818 out_up: 819 mutex_unlock(&u->readlock); 820 out: 821 return err; 822 823 out_mknod_dput: 824 dput(dentry); 825 out_mknod_unlock: 826 mutex_unlock(&nd.dentry->d_inode->i_mutex); 827 path_release(&nd); 828 out_mknod_parent: 829 if (err==-EEXIST) 830 err=-EADDRINUSE; 831 unix_release_addr(addr); 832 goto out_up; 833 } 834 835 static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 836 int alen, int flags) 837 { 838 struct sock *sk = sock->sk; 839 struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr; 840 struct sock *other; 841 unsigned hash; 842 int err; 843 844 if (addr->sa_family != AF_UNSPEC) { 845 err = unix_mkname(sunaddr, alen, &hash); 846 if (err < 0) 847 goto out; 848 alen = err; 849 850 if (test_bit(SOCK_PASSCRED, &sock->flags) && 851 !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0) 852 goto out; 853 854 other=unix_find_other(sunaddr, alen, sock->type, hash, &err); 855 if (!other) 856 goto out; 857 858 unix_state_wlock(sk); 859 860 err = -EPERM; 861 if (!unix_may_send(sk, other)) 862 goto out_unlock; 863 864 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 865 if (err) 866 goto out_unlock; 867 868 } else { 869 /* 870 * 1003.1g breaking connected state with AF_UNSPEC 871 */ 872 other = NULL; 873 unix_state_wlock(sk); 874 } 875 876 /* 877 * If it was connected, reconnect. 878 */ 879 if (unix_peer(sk)) { 880 struct sock *old_peer = unix_peer(sk); 881 unix_peer(sk)=other; 882 unix_state_wunlock(sk); 883 884 if (other != old_peer) 885 unix_dgram_disconnected(sk, old_peer); 886 sock_put(old_peer); 887 } else { 888 unix_peer(sk)=other; 889 unix_state_wunlock(sk); 890 } 891 return 0; 892 893 out_unlock: 894 unix_state_wunlock(sk); 895 sock_put(other); 896 out: 897 return err; 898 } 899 900 static long unix_wait_for_peer(struct sock *other, long timeo) 901 { 902 struct unix_sock *u = unix_sk(other); 903 int sched; 904 DEFINE_WAIT(wait); 905 906 prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); 907 908 sched = !sock_flag(other, SOCK_DEAD) && 909 !(other->sk_shutdown & RCV_SHUTDOWN) && 910 (skb_queue_len(&other->sk_receive_queue) > 911 other->sk_max_ack_backlog); 912 913 unix_state_runlock(other); 914 915 if (sched) 916 timeo = schedule_timeout(timeo); 917 918 finish_wait(&u->peer_wait, &wait); 919 return timeo; 920 } 921 922 static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 923 int addr_len, int flags) 924 { 925 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 926 struct sock *sk = sock->sk; 927 struct unix_sock *u = unix_sk(sk), *newu, *otheru; 928 struct sock *newsk = NULL; 929 struct sock *other = NULL; 930 struct sk_buff *skb = NULL; 931 unsigned hash; 932 int st; 933 int err; 934 long timeo; 935 936 err = unix_mkname(sunaddr, addr_len, &hash); 937 if (err < 0) 938 goto out; 939 addr_len = err; 940 941 if (test_bit(SOCK_PASSCRED, &sock->flags) 942 && !u->addr && (err = unix_autobind(sock)) != 0) 943 goto out; 944 945 timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); 946 947 /* First of all allocate resources. 948 If we will make it after state is locked, 949 we will have to recheck all again in any case. 950 */ 951 952 err = -ENOMEM; 953 954 /* create new sock for complete connection */ 955 newsk = unix_create1(NULL); 956 if (newsk == NULL) 957 goto out; 958 959 /* Allocate skb for sending to listening sock */ 960 skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); 961 if (skb == NULL) 962 goto out; 963 964 restart: 965 /* Find listening sock. */ 966 other = unix_find_other(sunaddr, addr_len, sk->sk_type, hash, &err); 967 if (!other) 968 goto out; 969 970 /* Latch state of peer */ 971 unix_state_rlock(other); 972 973 /* Apparently VFS overslept socket death. Retry. */ 974 if (sock_flag(other, SOCK_DEAD)) { 975 unix_state_runlock(other); 976 sock_put(other); 977 goto restart; 978 } 979 980 err = -ECONNREFUSED; 981 if (other->sk_state != TCP_LISTEN) 982 goto out_unlock; 983 984 if (skb_queue_len(&other->sk_receive_queue) > 985 other->sk_max_ack_backlog) { 986 err = -EAGAIN; 987 if (!timeo) 988 goto out_unlock; 989 990 timeo = unix_wait_for_peer(other, timeo); 991 992 err = sock_intr_errno(timeo); 993 if (signal_pending(current)) 994 goto out; 995 sock_put(other); 996 goto restart; 997 } 998 999 /* Latch our state. 1000 1001 It is tricky place. We need to grab write lock and cannot 1002 drop lock on peer. It is dangerous because deadlock is 1003 possible. Connect to self case and simultaneous 1004 attempt to connect are eliminated by checking socket 1005 state. other is TCP_LISTEN, if sk is TCP_LISTEN we 1006 check this before attempt to grab lock. 1007 1008 Well, and we have to recheck the state after socket locked. 1009 */ 1010 st = sk->sk_state; 1011 1012 switch (st) { 1013 case TCP_CLOSE: 1014 /* This is ok... continue with connect */ 1015 break; 1016 case TCP_ESTABLISHED: 1017 /* Socket is already connected */ 1018 err = -EISCONN; 1019 goto out_unlock; 1020 default: 1021 err = -EINVAL; 1022 goto out_unlock; 1023 } 1024 1025 unix_state_wlock(sk); 1026 1027 if (sk->sk_state != st) { 1028 unix_state_wunlock(sk); 1029 unix_state_runlock(other); 1030 sock_put(other); 1031 goto restart; 1032 } 1033 1034 err = security_unix_stream_connect(sock, other->sk_socket, newsk); 1035 if (err) { 1036 unix_state_wunlock(sk); 1037 goto out_unlock; 1038 } 1039 1040 /* The way is open! Fastly set all the necessary fields... */ 1041 1042 sock_hold(sk); 1043 unix_peer(newsk) = sk; 1044 newsk->sk_state = TCP_ESTABLISHED; 1045 newsk->sk_type = sk->sk_type; 1046 newsk->sk_peercred.pid = current->tgid; 1047 newsk->sk_peercred.uid = current->euid; 1048 newsk->sk_peercred.gid = current->egid; 1049 newu = unix_sk(newsk); 1050 newsk->sk_sleep = &newu->peer_wait; 1051 otheru = unix_sk(other); 1052 1053 /* copy address information from listening to new sock*/ 1054 if (otheru->addr) { 1055 atomic_inc(&otheru->addr->refcnt); 1056 newu->addr = otheru->addr; 1057 } 1058 if (otheru->dentry) { 1059 newu->dentry = dget(otheru->dentry); 1060 newu->mnt = mntget(otheru->mnt); 1061 } 1062 1063 /* Set credentials */ 1064 sk->sk_peercred = other->sk_peercred; 1065 1066 sock->state = SS_CONNECTED; 1067 sk->sk_state = TCP_ESTABLISHED; 1068 sock_hold(newsk); 1069 1070 smp_mb__after_atomic_inc(); /* sock_hold() does an atomic_inc() */ 1071 unix_peer(sk) = newsk; 1072 1073 unix_state_wunlock(sk); 1074 1075 /* take ten and and send info to listening sock */ 1076 spin_lock(&other->sk_receive_queue.lock); 1077 __skb_queue_tail(&other->sk_receive_queue, skb); 1078 /* Undo artificially decreased inflight after embrion 1079 * is installed to listening socket. */ 1080 atomic_inc(&newu->inflight); 1081 spin_unlock(&other->sk_receive_queue.lock); 1082 unix_state_runlock(other); 1083 other->sk_data_ready(other, 0); 1084 sock_put(other); 1085 return 0; 1086 1087 out_unlock: 1088 if (other) 1089 unix_state_runlock(other); 1090 1091 out: 1092 if (skb) 1093 kfree_skb(skb); 1094 if (newsk) 1095 unix_release_sock(newsk, 0); 1096 if (other) 1097 sock_put(other); 1098 return err; 1099 } 1100 1101 static int unix_socketpair(struct socket *socka, struct socket *sockb) 1102 { 1103 struct sock *ska=socka->sk, *skb = sockb->sk; 1104 1105 /* Join our sockets back to back */ 1106 sock_hold(ska); 1107 sock_hold(skb); 1108 unix_peer(ska)=skb; 1109 unix_peer(skb)=ska; 1110 ska->sk_peercred.pid = skb->sk_peercred.pid = current->tgid; 1111 ska->sk_peercred.uid = skb->sk_peercred.uid = current->euid; 1112 ska->sk_peercred.gid = skb->sk_peercred.gid = current->egid; 1113 1114 if (ska->sk_type != SOCK_DGRAM) { 1115 ska->sk_state = TCP_ESTABLISHED; 1116 skb->sk_state = TCP_ESTABLISHED; 1117 socka->state = SS_CONNECTED; 1118 sockb->state = SS_CONNECTED; 1119 } 1120 return 0; 1121 } 1122 1123 static int unix_accept(struct socket *sock, struct socket *newsock, int flags) 1124 { 1125 struct sock *sk = sock->sk; 1126 struct sock *tsk; 1127 struct sk_buff *skb; 1128 int err; 1129 1130 err = -EOPNOTSUPP; 1131 if (sock->type!=SOCK_STREAM && sock->type!=SOCK_SEQPACKET) 1132 goto out; 1133 1134 err = -EINVAL; 1135 if (sk->sk_state != TCP_LISTEN) 1136 goto out; 1137 1138 /* If socket state is TCP_LISTEN it cannot change (for now...), 1139 * so that no locks are necessary. 1140 */ 1141 1142 skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err); 1143 if (!skb) { 1144 /* This means receive shutdown. */ 1145 if (err == 0) 1146 err = -EINVAL; 1147 goto out; 1148 } 1149 1150 tsk = skb->sk; 1151 skb_free_datagram(sk, skb); 1152 wake_up_interruptible(&unix_sk(sk)->peer_wait); 1153 1154 /* attach accepted sock to socket */ 1155 unix_state_wlock(tsk); 1156 newsock->state = SS_CONNECTED; 1157 sock_graft(tsk, newsock); 1158 unix_state_wunlock(tsk); 1159 return 0; 1160 1161 out: 1162 return err; 1163 } 1164 1165 1166 static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer) 1167 { 1168 struct sock *sk = sock->sk; 1169 struct unix_sock *u; 1170 struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr; 1171 int err = 0; 1172 1173 if (peer) { 1174 sk = unix_peer_get(sk); 1175 1176 err = -ENOTCONN; 1177 if (!sk) 1178 goto out; 1179 err = 0; 1180 } else { 1181 sock_hold(sk); 1182 } 1183 1184 u = unix_sk(sk); 1185 unix_state_rlock(sk); 1186 if (!u->addr) { 1187 sunaddr->sun_family = AF_UNIX; 1188 sunaddr->sun_path[0] = 0; 1189 *uaddr_len = sizeof(short); 1190 } else { 1191 struct unix_address *addr = u->addr; 1192 1193 *uaddr_len = addr->len; 1194 memcpy(sunaddr, addr->name, *uaddr_len); 1195 } 1196 unix_state_runlock(sk); 1197 sock_put(sk); 1198 out: 1199 return err; 1200 } 1201 1202 static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1203 { 1204 int i; 1205 1206 scm->fp = UNIXCB(skb).fp; 1207 skb->destructor = sock_wfree; 1208 UNIXCB(skb).fp = NULL; 1209 1210 for (i=scm->fp->count-1; i>=0; i--) 1211 unix_notinflight(scm->fp->fp[i]); 1212 } 1213 1214 static void unix_destruct_fds(struct sk_buff *skb) 1215 { 1216 struct scm_cookie scm; 1217 memset(&scm, 0, sizeof(scm)); 1218 unix_detach_fds(&scm, skb); 1219 1220 /* Alas, it calls VFS */ 1221 /* So fscking what? fput() had been SMP-safe since the last Summer */ 1222 scm_destroy(&scm); 1223 sock_wfree(skb); 1224 } 1225 1226 static void unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 1227 { 1228 int i; 1229 for (i=scm->fp->count-1; i>=0; i--) 1230 unix_inflight(scm->fp->fp[i]); 1231 UNIXCB(skb).fp = scm->fp; 1232 skb->destructor = unix_destruct_fds; 1233 scm->fp = NULL; 1234 } 1235 1236 /* 1237 * Send AF_UNIX data. 1238 */ 1239 1240 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 1241 struct msghdr *msg, size_t len) 1242 { 1243 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1244 struct sock *sk = sock->sk; 1245 struct unix_sock *u = unix_sk(sk); 1246 struct sockaddr_un *sunaddr=msg->msg_name; 1247 struct sock *other = NULL; 1248 int namelen = 0; /* fake GCC */ 1249 int err; 1250 unsigned hash; 1251 struct sk_buff *skb; 1252 long timeo; 1253 struct scm_cookie tmp_scm; 1254 1255 if (NULL == siocb->scm) 1256 siocb->scm = &tmp_scm; 1257 err = scm_send(sock, msg, siocb->scm); 1258 if (err < 0) 1259 return err; 1260 1261 err = -EOPNOTSUPP; 1262 if (msg->msg_flags&MSG_OOB) 1263 goto out; 1264 1265 if (msg->msg_namelen) { 1266 err = unix_mkname(sunaddr, msg->msg_namelen, &hash); 1267 if (err < 0) 1268 goto out; 1269 namelen = err; 1270 } else { 1271 sunaddr = NULL; 1272 err = -ENOTCONN; 1273 other = unix_peer_get(sk); 1274 if (!other) 1275 goto out; 1276 } 1277 1278 if (test_bit(SOCK_PASSCRED, &sock->flags) 1279 && !u->addr && (err = unix_autobind(sock)) != 0) 1280 goto out; 1281 1282 err = -EMSGSIZE; 1283 if (len > sk->sk_sndbuf - 32) 1284 goto out; 1285 1286 skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err); 1287 if (skb==NULL) 1288 goto out; 1289 1290 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1291 if (siocb->scm->fp) 1292 unix_attach_fds(siocb->scm, skb); 1293 1294 skb->h.raw = skb->data; 1295 err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len); 1296 if (err) 1297 goto out_free; 1298 1299 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1300 1301 restart: 1302 if (!other) { 1303 err = -ECONNRESET; 1304 if (sunaddr == NULL) 1305 goto out_free; 1306 1307 other = unix_find_other(sunaddr, namelen, sk->sk_type, 1308 hash, &err); 1309 if (other==NULL) 1310 goto out_free; 1311 } 1312 1313 unix_state_rlock(other); 1314 err = -EPERM; 1315 if (!unix_may_send(sk, other)) 1316 goto out_unlock; 1317 1318 if (sock_flag(other, SOCK_DEAD)) { 1319 /* 1320 * Check with 1003.1g - what should 1321 * datagram error 1322 */ 1323 unix_state_runlock(other); 1324 sock_put(other); 1325 1326 err = 0; 1327 unix_state_wlock(sk); 1328 if (unix_peer(sk) == other) { 1329 unix_peer(sk)=NULL; 1330 unix_state_wunlock(sk); 1331 1332 unix_dgram_disconnected(sk, other); 1333 sock_put(other); 1334 err = -ECONNREFUSED; 1335 } else { 1336 unix_state_wunlock(sk); 1337 } 1338 1339 other = NULL; 1340 if (err) 1341 goto out_free; 1342 goto restart; 1343 } 1344 1345 err = -EPIPE; 1346 if (other->sk_shutdown & RCV_SHUTDOWN) 1347 goto out_unlock; 1348 1349 if (sk->sk_type != SOCK_SEQPACKET) { 1350 err = security_unix_may_send(sk->sk_socket, other->sk_socket); 1351 if (err) 1352 goto out_unlock; 1353 } 1354 1355 if (unix_peer(other) != sk && 1356 (skb_queue_len(&other->sk_receive_queue) > 1357 other->sk_max_ack_backlog)) { 1358 if (!timeo) { 1359 err = -EAGAIN; 1360 goto out_unlock; 1361 } 1362 1363 timeo = unix_wait_for_peer(other, timeo); 1364 1365 err = sock_intr_errno(timeo); 1366 if (signal_pending(current)) 1367 goto out_free; 1368 1369 goto restart; 1370 } 1371 1372 skb_queue_tail(&other->sk_receive_queue, skb); 1373 unix_state_runlock(other); 1374 other->sk_data_ready(other, len); 1375 sock_put(other); 1376 scm_destroy(siocb->scm); 1377 return len; 1378 1379 out_unlock: 1380 unix_state_runlock(other); 1381 out_free: 1382 kfree_skb(skb); 1383 out: 1384 if (other) 1385 sock_put(other); 1386 scm_destroy(siocb->scm); 1387 return err; 1388 } 1389 1390 1391 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 1392 struct msghdr *msg, size_t len) 1393 { 1394 struct sock_iocb *siocb = kiocb_to_siocb(kiocb); 1395 struct sock *sk = sock->sk; 1396 struct sock *other = NULL; 1397 struct sockaddr_un *sunaddr=msg->msg_name; 1398 int err,size; 1399 struct sk_buff *skb; 1400 int sent=0; 1401 struct scm_cookie tmp_scm; 1402 1403 if (NULL == siocb->scm) 1404 siocb->scm = &tmp_scm; 1405 err = scm_send(sock, msg, siocb->scm); 1406 if (err < 0) 1407 return err; 1408 1409 err = -EOPNOTSUPP; 1410 if (msg->msg_flags&MSG_OOB) 1411 goto out_err; 1412 1413 if (msg->msg_namelen) { 1414 err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; 1415 goto out_err; 1416 } else { 1417 sunaddr = NULL; 1418 err = -ENOTCONN; 1419 other = unix_peer(sk); 1420 if (!other) 1421 goto out_err; 1422 } 1423 1424 if (sk->sk_shutdown & SEND_SHUTDOWN) 1425 goto pipe_err; 1426 1427 while(sent < len) 1428 { 1429 /* 1430 * Optimisation for the fact that under 0.01% of X 1431 * messages typically need breaking up. 1432 */ 1433 1434 size = len-sent; 1435 1436 /* Keep two messages in the pipe so it schedules better */ 1437 if (size > ((sk->sk_sndbuf >> 1) - 64)) 1438 size = (sk->sk_sndbuf >> 1) - 64; 1439 1440 if (size > SKB_MAX_ALLOC) 1441 size = SKB_MAX_ALLOC; 1442 1443 /* 1444 * Grab a buffer 1445 */ 1446 1447 skb=sock_alloc_send_skb(sk,size,msg->msg_flags&MSG_DONTWAIT, &err); 1448 1449 if (skb==NULL) 1450 goto out_err; 1451 1452 /* 1453 * If you pass two values to the sock_alloc_send_skb 1454 * it tries to grab the large buffer with GFP_NOFS 1455 * (which can fail easily), and if it fails grab the 1456 * fallback size buffer which is under a page and will 1457 * succeed. [Alan] 1458 */ 1459 size = min_t(int, size, skb_tailroom(skb)); 1460 1461 memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); 1462 if (siocb->scm->fp) 1463 unix_attach_fds(siocb->scm, skb); 1464 1465 if ((err = memcpy_fromiovec(skb_put(skb,size), msg->msg_iov, size)) != 0) { 1466 kfree_skb(skb); 1467 goto out_err; 1468 } 1469 1470 unix_state_rlock(other); 1471 1472 if (sock_flag(other, SOCK_DEAD) || 1473 (other->sk_shutdown & RCV_SHUTDOWN)) 1474 goto pipe_err_free; 1475 1476 skb_queue_tail(&other->sk_receive_queue, skb); 1477 unix_state_runlock(other); 1478 other->sk_data_ready(other, size); 1479 sent+=size; 1480 } 1481 1482 scm_destroy(siocb->scm); 1483 siocb->scm = NULL; 1484 1485 return sent; 1486 1487 pipe_err_free: 1488 unix_state_runlock(other); 1489 kfree_skb(skb); 1490 pipe_err: 1491 if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL)) 1492 send_sig(SIGPIPE,current,0); 1493 err = -EPIPE; 1494 out_err: 1495 scm_destroy(siocb->scm); 1496 siocb->scm = NULL; 1497 return sent ? : err; 1498 } 1499 1500 static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock, 1501 struct msghdr *msg, size_t len) 1502 { 1503 int err; 1504 struct sock *sk = sock->sk; 1505 1506 err = sock_error(sk); 1507 if (err) 1508 return err; 1509 1510 if (sk->sk_state != TCP_ESTABLISHED) 1511 return -ENOTCONN; 1512 1513 if (msg->msg_namelen) 1514 msg->msg_namelen = 0; 1515 1516 return unix_dgram_sendmsg(kiocb, sock, msg, len); 1517 } 1518 1519 static void unix_copy_addr(struct msghdr *msg, struct sock *sk) 1520 { 1521 struct unix_sock *u = unix_sk(sk); 1522 1523 msg->msg_namelen = 0; 1524 if (u->addr) { 1525 msg->msg_namelen = u->addr->len; 1526 memcpy(msg->msg_name, u->addr->name, u->addr->len); 1527 } 1528 } 1529 1530 static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 1531 struct msghdr *msg, size_t size, 1532 int flags) 1533 { 1534 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1535 struct scm_cookie tmp_scm; 1536 struct sock *sk = sock->sk; 1537 struct unix_sock *u = unix_sk(sk); 1538 int noblock = flags & MSG_DONTWAIT; 1539 struct sk_buff *skb; 1540 int err; 1541 1542 err = -EOPNOTSUPP; 1543 if (flags&MSG_OOB) 1544 goto out; 1545 1546 msg->msg_namelen = 0; 1547 1548 mutex_lock(&u->readlock); 1549 1550 skb = skb_recv_datagram(sk, flags, noblock, &err); 1551 if (!skb) 1552 goto out_unlock; 1553 1554 wake_up_interruptible(&u->peer_wait); 1555 1556 if (msg->msg_name) 1557 unix_copy_addr(msg, skb->sk); 1558 1559 if (size > skb->len) 1560 size = skb->len; 1561 else if (size < skb->len) 1562 msg->msg_flags |= MSG_TRUNC; 1563 1564 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size); 1565 if (err) 1566 goto out_free; 1567 1568 if (!siocb->scm) { 1569 siocb->scm = &tmp_scm; 1570 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1571 } 1572 siocb->scm->creds = *UNIXCREDS(skb); 1573 1574 if (!(flags & MSG_PEEK)) 1575 { 1576 if (UNIXCB(skb).fp) 1577 unix_detach_fds(siocb->scm, skb); 1578 } 1579 else 1580 { 1581 /* It is questionable: on PEEK we could: 1582 - do not return fds - good, but too simple 8) 1583 - return fds, and do not return them on read (old strategy, 1584 apparently wrong) 1585 - clone fds (I chose it for now, it is the most universal 1586 solution) 1587 1588 POSIX 1003.1g does not actually define this clearly 1589 at all. POSIX 1003.1g doesn't define a lot of things 1590 clearly however! 1591 1592 */ 1593 if (UNIXCB(skb).fp) 1594 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1595 } 1596 err = size; 1597 1598 scm_recv(sock, msg, siocb->scm, flags); 1599 1600 out_free: 1601 skb_free_datagram(sk,skb); 1602 out_unlock: 1603 mutex_unlock(&u->readlock); 1604 out: 1605 return err; 1606 } 1607 1608 /* 1609 * Sleep until data has arrive. But check for races.. 1610 */ 1611 1612 static long unix_stream_data_wait(struct sock * sk, long timeo) 1613 { 1614 DEFINE_WAIT(wait); 1615 1616 unix_state_rlock(sk); 1617 1618 for (;;) { 1619 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); 1620 1621 if (!skb_queue_empty(&sk->sk_receive_queue) || 1622 sk->sk_err || 1623 (sk->sk_shutdown & RCV_SHUTDOWN) || 1624 signal_pending(current) || 1625 !timeo) 1626 break; 1627 1628 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1629 unix_state_runlock(sk); 1630 timeo = schedule_timeout(timeo); 1631 unix_state_rlock(sk); 1632 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); 1633 } 1634 1635 finish_wait(sk->sk_sleep, &wait); 1636 unix_state_runlock(sk); 1637 return timeo; 1638 } 1639 1640 1641 1642 static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 1643 struct msghdr *msg, size_t size, 1644 int flags) 1645 { 1646 struct sock_iocb *siocb = kiocb_to_siocb(iocb); 1647 struct scm_cookie tmp_scm; 1648 struct sock *sk = sock->sk; 1649 struct unix_sock *u = unix_sk(sk); 1650 struct sockaddr_un *sunaddr=msg->msg_name; 1651 int copied = 0; 1652 int check_creds = 0; 1653 int target; 1654 int err = 0; 1655 long timeo; 1656 1657 err = -EINVAL; 1658 if (sk->sk_state != TCP_ESTABLISHED) 1659 goto out; 1660 1661 err = -EOPNOTSUPP; 1662 if (flags&MSG_OOB) 1663 goto out; 1664 1665 target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); 1666 timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); 1667 1668 msg->msg_namelen = 0; 1669 1670 /* Lock the socket to prevent queue disordering 1671 * while sleeps in memcpy_tomsg 1672 */ 1673 1674 if (!siocb->scm) { 1675 siocb->scm = &tmp_scm; 1676 memset(&tmp_scm, 0, sizeof(tmp_scm)); 1677 } 1678 1679 mutex_lock(&u->readlock); 1680 1681 do 1682 { 1683 int chunk; 1684 struct sk_buff *skb; 1685 1686 skb = skb_dequeue(&sk->sk_receive_queue); 1687 if (skb==NULL) 1688 { 1689 if (copied >= target) 1690 break; 1691 1692 /* 1693 * POSIX 1003.1g mandates this order. 1694 */ 1695 1696 if ((err = sock_error(sk)) != 0) 1697 break; 1698 if (sk->sk_shutdown & RCV_SHUTDOWN) 1699 break; 1700 err = -EAGAIN; 1701 if (!timeo) 1702 break; 1703 mutex_unlock(&u->readlock); 1704 1705 timeo = unix_stream_data_wait(sk, timeo); 1706 1707 if (signal_pending(current)) { 1708 err = sock_intr_errno(timeo); 1709 goto out; 1710 } 1711 mutex_lock(&u->readlock); 1712 continue; 1713 } 1714 1715 if (check_creds) { 1716 /* Never glue messages from different writers */ 1717 if (memcmp(UNIXCREDS(skb), &siocb->scm->creds, sizeof(siocb->scm->creds)) != 0) { 1718 skb_queue_head(&sk->sk_receive_queue, skb); 1719 break; 1720 } 1721 } else { 1722 /* Copy credentials */ 1723 siocb->scm->creds = *UNIXCREDS(skb); 1724 check_creds = 1; 1725 } 1726 1727 /* Copy address just once */ 1728 if (sunaddr) 1729 { 1730 unix_copy_addr(msg, skb->sk); 1731 sunaddr = NULL; 1732 } 1733 1734 chunk = min_t(unsigned int, skb->len, size); 1735 if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) { 1736 skb_queue_head(&sk->sk_receive_queue, skb); 1737 if (copied == 0) 1738 copied = -EFAULT; 1739 break; 1740 } 1741 copied += chunk; 1742 size -= chunk; 1743 1744 /* Mark read part of skb as used */ 1745 if (!(flags & MSG_PEEK)) 1746 { 1747 skb_pull(skb, chunk); 1748 1749 if (UNIXCB(skb).fp) 1750 unix_detach_fds(siocb->scm, skb); 1751 1752 /* put the skb back if we didn't use it up.. */ 1753 if (skb->len) 1754 { 1755 skb_queue_head(&sk->sk_receive_queue, skb); 1756 break; 1757 } 1758 1759 kfree_skb(skb); 1760 1761 if (siocb->scm->fp) 1762 break; 1763 } 1764 else 1765 { 1766 /* It is questionable, see note in unix_dgram_recvmsg. 1767 */ 1768 if (UNIXCB(skb).fp) 1769 siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp); 1770 1771 /* put message back and return */ 1772 skb_queue_head(&sk->sk_receive_queue, skb); 1773 break; 1774 } 1775 } while (size); 1776 1777 mutex_unlock(&u->readlock); 1778 scm_recv(sock, msg, siocb->scm, flags); 1779 out: 1780 return copied ? : err; 1781 } 1782 1783 static int unix_shutdown(struct socket *sock, int mode) 1784 { 1785 struct sock *sk = sock->sk; 1786 struct sock *other; 1787 1788 mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN); 1789 1790 if (mode) { 1791 unix_state_wlock(sk); 1792 sk->sk_shutdown |= mode; 1793 other=unix_peer(sk); 1794 if (other) 1795 sock_hold(other); 1796 unix_state_wunlock(sk); 1797 sk->sk_state_change(sk); 1798 1799 if (other && 1800 (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { 1801 1802 int peer_mode = 0; 1803 1804 if (mode&RCV_SHUTDOWN) 1805 peer_mode |= SEND_SHUTDOWN; 1806 if (mode&SEND_SHUTDOWN) 1807 peer_mode |= RCV_SHUTDOWN; 1808 unix_state_wlock(other); 1809 other->sk_shutdown |= peer_mode; 1810 unix_state_wunlock(other); 1811 other->sk_state_change(other); 1812 read_lock(&other->sk_callback_lock); 1813 if (peer_mode == SHUTDOWN_MASK) 1814 sk_wake_async(other,1,POLL_HUP); 1815 else if (peer_mode & RCV_SHUTDOWN) 1816 sk_wake_async(other,1,POLL_IN); 1817 read_unlock(&other->sk_callback_lock); 1818 } 1819 if (other) 1820 sock_put(other); 1821 } 1822 return 0; 1823 } 1824 1825 static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 1826 { 1827 struct sock *sk = sock->sk; 1828 long amount=0; 1829 int err; 1830 1831 switch(cmd) 1832 { 1833 case SIOCOUTQ: 1834 amount = atomic_read(&sk->sk_wmem_alloc); 1835 err = put_user(amount, (int __user *)arg); 1836 break; 1837 case SIOCINQ: 1838 { 1839 struct sk_buff *skb; 1840 1841 if (sk->sk_state == TCP_LISTEN) { 1842 err = -EINVAL; 1843 break; 1844 } 1845 1846 spin_lock(&sk->sk_receive_queue.lock); 1847 if (sk->sk_type == SOCK_STREAM || 1848 sk->sk_type == SOCK_SEQPACKET) { 1849 skb_queue_walk(&sk->sk_receive_queue, skb) 1850 amount += skb->len; 1851 } else { 1852 skb = skb_peek(&sk->sk_receive_queue); 1853 if (skb) 1854 amount=skb->len; 1855 } 1856 spin_unlock(&sk->sk_receive_queue.lock); 1857 err = put_user(amount, (int __user *)arg); 1858 break; 1859 } 1860 1861 default: 1862 err = -ENOIOCTLCMD; 1863 break; 1864 } 1865 return err; 1866 } 1867 1868 static unsigned int unix_poll(struct file * file, struct socket *sock, poll_table *wait) 1869 { 1870 struct sock *sk = sock->sk; 1871 unsigned int mask; 1872 1873 poll_wait(file, sk->sk_sleep, wait); 1874 mask = 0; 1875 1876 /* exceptional events? */ 1877 if (sk->sk_err) 1878 mask |= POLLERR; 1879 if (sk->sk_shutdown == SHUTDOWN_MASK) 1880 mask |= POLLHUP; 1881 if (sk->sk_shutdown & RCV_SHUTDOWN) 1882 mask |= POLLRDHUP; 1883 1884 /* readable? */ 1885 if (!skb_queue_empty(&sk->sk_receive_queue) || 1886 (sk->sk_shutdown & RCV_SHUTDOWN)) 1887 mask |= POLLIN | POLLRDNORM; 1888 1889 /* Connection-based need to check for termination and startup */ 1890 if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && sk->sk_state == TCP_CLOSE) 1891 mask |= POLLHUP; 1892 1893 /* 1894 * we set writable also when the other side has shut down the 1895 * connection. This prevents stuck sockets. 1896 */ 1897 if (unix_writable(sk)) 1898 mask |= POLLOUT | POLLWRNORM | POLLWRBAND; 1899 1900 return mask; 1901 } 1902 1903 1904 #ifdef CONFIG_PROC_FS 1905 static struct sock *unix_seq_idx(int *iter, loff_t pos) 1906 { 1907 loff_t off = 0; 1908 struct sock *s; 1909 1910 for (s = first_unix_socket(iter); s; s = next_unix_socket(iter, s)) { 1911 if (off == pos) 1912 return s; 1913 ++off; 1914 } 1915 return NULL; 1916 } 1917 1918 1919 static void *unix_seq_start(struct seq_file *seq, loff_t *pos) 1920 { 1921 spin_lock(&unix_table_lock); 1922 return *pos ? unix_seq_idx(seq->private, *pos - 1) : ((void *) 1); 1923 } 1924 1925 static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1926 { 1927 ++*pos; 1928 1929 if (v == (void *)1) 1930 return first_unix_socket(seq->private); 1931 return next_unix_socket(seq->private, v); 1932 } 1933 1934 static void unix_seq_stop(struct seq_file *seq, void *v) 1935 { 1936 spin_unlock(&unix_table_lock); 1937 } 1938 1939 static int unix_seq_show(struct seq_file *seq, void *v) 1940 { 1941 1942 if (v == (void *)1) 1943 seq_puts(seq, "Num RefCount Protocol Flags Type St " 1944 "Inode Path\n"); 1945 else { 1946 struct sock *s = v; 1947 struct unix_sock *u = unix_sk(s); 1948 unix_state_rlock(s); 1949 1950 seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu", 1951 s, 1952 atomic_read(&s->sk_refcnt), 1953 0, 1954 s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, 1955 s->sk_type, 1956 s->sk_socket ? 1957 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : 1958 (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), 1959 sock_i_ino(s)); 1960 1961 if (u->addr) { 1962 int i, len; 1963 seq_putc(seq, ' '); 1964 1965 i = 0; 1966 len = u->addr->len - sizeof(short); 1967 if (!UNIX_ABSTRACT(s)) 1968 len--; 1969 else { 1970 seq_putc(seq, '@'); 1971 i++; 1972 } 1973 for ( ; i < len; i++) 1974 seq_putc(seq, u->addr->name->sun_path[i]); 1975 } 1976 unix_state_runlock(s); 1977 seq_putc(seq, '\n'); 1978 } 1979 1980 return 0; 1981 } 1982 1983 static struct seq_operations unix_seq_ops = { 1984 .start = unix_seq_start, 1985 .next = unix_seq_next, 1986 .stop = unix_seq_stop, 1987 .show = unix_seq_show, 1988 }; 1989 1990 1991 static int unix_seq_open(struct inode *inode, struct file *file) 1992 { 1993 struct seq_file *seq; 1994 int rc = -ENOMEM; 1995 int *iter = kmalloc(sizeof(int), GFP_KERNEL); 1996 1997 if (!iter) 1998 goto out; 1999 2000 rc = seq_open(file, &unix_seq_ops); 2001 if (rc) 2002 goto out_kfree; 2003 2004 seq = file->private_data; 2005 seq->private = iter; 2006 *iter = 0; 2007 out: 2008 return rc; 2009 out_kfree: 2010 kfree(iter); 2011 goto out; 2012 } 2013 2014 static struct file_operations unix_seq_fops = { 2015 .owner = THIS_MODULE, 2016 .open = unix_seq_open, 2017 .read = seq_read, 2018 .llseek = seq_lseek, 2019 .release = seq_release_private, 2020 }; 2021 2022 #endif 2023 2024 static struct net_proto_family unix_family_ops = { 2025 .family = PF_UNIX, 2026 .create = unix_create, 2027 .owner = THIS_MODULE, 2028 }; 2029 2030 static int __init af_unix_init(void) 2031 { 2032 int rc = -1; 2033 struct sk_buff *dummy_skb; 2034 2035 if (sizeof(struct unix_skb_parms) > sizeof(dummy_skb->cb)) { 2036 printk(KERN_CRIT "%s: panic\n", __FUNCTION__); 2037 goto out; 2038 } 2039 2040 rc = proto_register(&unix_proto, 1); 2041 if (rc != 0) { 2042 printk(KERN_CRIT "%s: Cannot create unix_sock SLAB cache!\n", 2043 __FUNCTION__); 2044 goto out; 2045 } 2046 2047 sock_register(&unix_family_ops); 2048 #ifdef CONFIG_PROC_FS 2049 proc_net_fops_create("unix", 0, &unix_seq_fops); 2050 #endif 2051 unix_sysctl_register(); 2052 out: 2053 return rc; 2054 } 2055 2056 static void __exit af_unix_exit(void) 2057 { 2058 sock_unregister(PF_UNIX); 2059 unix_sysctl_unregister(); 2060 proc_net_remove("unix"); 2061 proto_unregister(&unix_proto); 2062 } 2063 2064 module_init(af_unix_init); 2065 module_exit(af_unix_exit); 2066 2067 MODULE_LICENSE("GPL"); 2068 MODULE_ALIAS_NETPROTO(PF_UNIX); 2069