Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/kern/uipc_usrreq.c
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1 /*- 2 * Copyright 2004-2005 Robert N. M. Watson 3 * Copyright (c) 1982, 1986, 1989, 1991, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 4. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD: releng/5.4/sys/kern/uipc_usrreq.c 145979 2005-05-07 03:58:25Z cperciva $"); 35 36 #include "opt_mac.h" 37 38 #include <sys/param.h> 39 #include <sys/domain.h> 40 #include <sys/fcntl.h> 41 #include <sys/malloc.h> /* XXX must be before <sys/file.h> */ 42 #include <sys/file.h> 43 #include <sys/filedesc.h> 44 #include <sys/jail.h> 45 #include <sys/kernel.h> 46 #include <sys/lock.h> 47 #include <sys/mac.h> 48 #include <sys/mbuf.h> 49 #include <sys/mutex.h> 50 #include <sys/namei.h> 51 #include <sys/proc.h> 52 #include <sys/protosw.h> 53 #include <sys/resourcevar.h> 54 #include <sys/socket.h> 55 #include <sys/socketvar.h> 56 #include <sys/signalvar.h> 57 #include <sys/stat.h> 58 #include <sys/sx.h> 59 #include <sys/sysctl.h> 60 #include <sys/systm.h> 61 #include <sys/un.h> 62 #include <sys/unpcb.h> 63 #include <sys/vnode.h> 64 65 #include <vm/uma.h> 66 67 static uma_zone_t unp_zone; 68 static unp_gen_t unp_gencnt; 69 static u_int unp_count; 70 71 static struct unp_head unp_shead, unp_dhead; 72 73 /* 74 * Unix communications domain. 75 * 76 * TODO: 77 * SEQPACKET, RDM 78 * rethink name space problems 79 * need a proper out-of-band 80 * lock pushdown 81 */ 82 static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; 83 static ino_t unp_ino; /* prototype for fake inode numbers */ 84 85 /* 86 * Currently, UNIX domain sockets are protected by a single subsystem lock, 87 * which covers global data structures and variables, the contents of each 88 * per-socket unpcb structure, and the so_pcb field in sockets attached to 89 * the UNIX domain. This provides for a moderate degree of paralellism, as 90 * receive operations on UNIX domain sockets do not need to acquire the 91 * subsystem lock. Finer grained locking to permit send() without acquiring 92 * a global lock would be a logical next step. 93 * 94 * The UNIX domain socket lock preceds all socket layer locks, including the 95 * socket lock and socket buffer lock, permitting UNIX domain socket code to 96 * call into socket support routines without releasing its locks. 97 * 98 * Some caution is required in areas where the UNIX domain socket code enters 99 * VFS in order to create or find rendezvous points. This results in 100 * dropping of the UNIX domain socket subsystem lock, acquisition of the 101 * Giant lock, and potential sleeping. This increases the chances of races, 102 * and exposes weaknesses in the socket->protocol API by offering poor 103 * failure modes. 104 */ 105 static struct mtx unp_mtx; 106 #define UNP_LOCK_INIT() \ 107 mtx_init(&unp_mtx, "unp", NULL, MTX_DEF) 108 #define UNP_LOCK() mtx_lock(&unp_mtx) 109 #define UNP_UNLOCK() mtx_unlock(&unp_mtx) 110 #define UNP_LOCK_ASSERT() mtx_assert(&unp_mtx, MA_OWNED) 111 #define UNP_UNLOCK_ASSERT() mtx_assert(&unp_mtx, MA_NOTOWNED) 112 113 static int unp_attach(struct socket *); 114 static void unp_detach(struct unpcb *); 115 static int unp_bind(struct unpcb *,struct sockaddr *, struct thread *); 116 static int unp_connect(struct socket *,struct sockaddr *, struct thread *); 117 static int unp_connect2(struct socket *so, struct socket *so2); 118 static void unp_disconnect(struct unpcb *); 119 static void unp_shutdown(struct unpcb *); 120 static void unp_drop(struct unpcb *, int); 121 static void unp_gc(void); 122 static void unp_scan(struct mbuf *, void (*)(struct file *)); 123 static void unp_mark(struct file *); 124 static void unp_discard(struct file *); 125 static void unp_freerights(struct file **, int); 126 static int unp_internalize(struct mbuf **, struct thread *); 127 static int unp_listen(struct socket *, struct unpcb *, struct thread *); 128 129 static int 130 uipc_abort(struct socket *so) 131 { 132 struct unpcb *unp; 133 134 UNP_LOCK(); 135 unp = sotounpcb(so); 136 if (unp == NULL) { 137 UNP_UNLOCK(); 138 return (EINVAL); 139 } 140 unp_drop(unp, ECONNABORTED); 141 unp_detach(unp); 142 UNP_UNLOCK_ASSERT(); 143 ACCEPT_LOCK(); 144 SOCK_LOCK(so); 145 sotryfree(so); 146 return (0); 147 } 148 149 static int 150 uipc_accept(struct socket *so, struct sockaddr **nam) 151 { 152 struct unpcb *unp; 153 const struct sockaddr *sa; 154 155 /* 156 * Pass back name of connected socket, 157 * if it was bound and we are still connected 158 * (our peer may have closed already!). 159 */ 160 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 161 UNP_LOCK(); 162 unp = sotounpcb(so); 163 if (unp == NULL) { 164 UNP_UNLOCK(); 165 free(*nam, M_SONAME); 166 *nam = NULL; 167 return (EINVAL); 168 } 169 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL) 170 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 171 else 172 sa = &sun_noname; 173 bcopy(sa, *nam, sa->sa_len); 174 UNP_UNLOCK(); 175 return (0); 176 } 177 178 static int 179 uipc_attach(struct socket *so, int proto, struct thread *td) 180 { 181 struct unpcb *unp = sotounpcb(so); 182 183 if (unp != NULL) 184 return (EISCONN); 185 return (unp_attach(so)); 186 } 187 188 static int 189 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 190 { 191 struct unpcb *unp; 192 int error; 193 194 UNP_LOCK(); 195 unp = sotounpcb(so); 196 if (unp == NULL) { 197 UNP_UNLOCK(); 198 return (EINVAL); 199 } 200 error = unp_bind(unp, nam, td); 201 UNP_UNLOCK(); 202 return (error); 203 } 204 205 static int 206 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 207 { 208 struct unpcb *unp; 209 int error; 210 211 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 212 213 UNP_LOCK(); 214 unp = sotounpcb(so); 215 if (unp == NULL) { 216 UNP_UNLOCK(); 217 return (EINVAL); 218 } 219 error = unp_connect(so, nam, td); 220 UNP_UNLOCK(); 221 return (error); 222 } 223 224 int 225 uipc_connect2(struct socket *so1, struct socket *so2) 226 { 227 struct unpcb *unp; 228 int error; 229 230 UNP_LOCK(); 231 unp = sotounpcb(so1); 232 if (unp == NULL) { 233 UNP_UNLOCK(); 234 return (EINVAL); 235 } 236 error = unp_connect2(so1, so2); 237 UNP_UNLOCK(); 238 return (error); 239 } 240 241 /* control is EOPNOTSUPP */ 242 243 static int 244 uipc_detach(struct socket *so) 245 { 246 struct unpcb *unp; 247 248 UNP_LOCK(); 249 unp = sotounpcb(so); 250 if (unp == NULL) { 251 UNP_UNLOCK(); 252 return (EINVAL); 253 } 254 unp_detach(unp); 255 UNP_UNLOCK_ASSERT(); 256 return (0); 257 } 258 259 static int 260 uipc_disconnect(struct socket *so) 261 { 262 struct unpcb *unp; 263 264 UNP_LOCK(); 265 unp = sotounpcb(so); 266 if (unp == NULL) { 267 UNP_UNLOCK(); 268 return (EINVAL); 269 } 270 unp_disconnect(unp); 271 UNP_UNLOCK(); 272 return (0); 273 } 274 275 static int 276 uipc_listen(struct socket *so, struct thread *td) 277 { 278 struct unpcb *unp; 279 int error; 280 281 UNP_LOCK(); 282 unp = sotounpcb(so); 283 if (unp == NULL || unp->unp_vnode == NULL) { 284 UNP_UNLOCK(); 285 return (EINVAL); 286 } 287 error = unp_listen(so, unp, td); 288 UNP_UNLOCK(); 289 return (error); 290 } 291 292 static int 293 uipc_peeraddr(struct socket *so, struct sockaddr **nam) 294 { 295 struct unpcb *unp; 296 const struct sockaddr *sa; 297 298 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 299 UNP_LOCK(); 300 unp = sotounpcb(so); 301 if (unp == NULL) { 302 UNP_UNLOCK(); 303 free(*nam, M_SONAME); 304 *nam = NULL; 305 return (EINVAL); 306 } 307 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr!= NULL) 308 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 309 else { 310 /* 311 * XXX: It seems that this test always fails even when 312 * connection is established. So, this else clause is 313 * added as workaround to return PF_LOCAL sockaddr. 314 */ 315 sa = &sun_noname; 316 } 317 bcopy(sa, *nam, sa->sa_len); 318 UNP_UNLOCK(); 319 return (0); 320 } 321 322 static int 323 uipc_rcvd(struct socket *so, int flags) 324 { 325 struct unpcb *unp; 326 struct socket *so2; 327 u_long newhiwat; 328 329 UNP_LOCK(); 330 unp = sotounpcb(so); 331 if (unp == NULL) { 332 UNP_UNLOCK(); 333 return (EINVAL); 334 } 335 switch (so->so_type) { 336 case SOCK_DGRAM: 337 panic("uipc_rcvd DGRAM?"); 338 /*NOTREACHED*/ 339 340 case SOCK_STREAM: 341 if (unp->unp_conn == NULL) 342 break; 343 so2 = unp->unp_conn->unp_socket; 344 SOCKBUF_LOCK(&so2->so_snd); 345 SOCKBUF_LOCK(&so->so_rcv); 346 /* 347 * Adjust backpressure on sender 348 * and wakeup any waiting to write. 349 */ 350 so2->so_snd.sb_mbmax += unp->unp_mbcnt - so->so_rcv.sb_mbcnt; 351 unp->unp_mbcnt = so->so_rcv.sb_mbcnt; 352 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - 353 so->so_rcv.sb_cc; 354 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, 355 newhiwat, RLIM_INFINITY); 356 unp->unp_cc = so->so_rcv.sb_cc; 357 SOCKBUF_UNLOCK(&so->so_rcv); 358 sowwakeup_locked(so2); 359 break; 360 361 default: 362 panic("uipc_rcvd unknown socktype"); 363 } 364 UNP_UNLOCK(); 365 return (0); 366 } 367 368 /* pru_rcvoob is EOPNOTSUPP */ 369 370 static int 371 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 372 struct mbuf *control, struct thread *td) 373 { 374 int error = 0; 375 struct unpcb *unp; 376 struct socket *so2; 377 u_long newhiwat; 378 379 unp = sotounpcb(so); 380 if (unp == NULL) { 381 error = EINVAL; 382 goto release; 383 } 384 if (flags & PRUS_OOB) { 385 error = EOPNOTSUPP; 386 goto release; 387 } 388 389 if (control != NULL && (error = unp_internalize(&control, td))) 390 goto release; 391 392 UNP_LOCK(); 393 unp = sotounpcb(so); 394 if (unp == NULL) { 395 UNP_UNLOCK(); 396 error = EINVAL; 397 goto dispose_release; 398 } 399 400 switch (so->so_type) { 401 case SOCK_DGRAM: 402 { 403 const struct sockaddr *from; 404 405 if (nam != NULL) { 406 if (unp->unp_conn != NULL) { 407 error = EISCONN; 408 break; 409 } 410 error = unp_connect(so, nam, td); 411 if (error) 412 break; 413 } else { 414 if (unp->unp_conn == NULL) { 415 error = ENOTCONN; 416 break; 417 } 418 } 419 so2 = unp->unp_conn->unp_socket; 420 if (unp->unp_addr != NULL) 421 from = (struct sockaddr *)unp->unp_addr; 422 else 423 from = &sun_noname; 424 SOCKBUF_LOCK(&so2->so_rcv); 425 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 426 sorwakeup_locked(so2); 427 m = NULL; 428 control = NULL; 429 } else { 430 SOCKBUF_UNLOCK(&so2->so_rcv); 431 error = ENOBUFS; 432 } 433 if (nam != NULL) 434 unp_disconnect(unp); 435 break; 436 } 437 438 case SOCK_STREAM: 439 /* Connect if not connected yet. */ 440 /* 441 * Note: A better implementation would complain 442 * if not equal to the peer's address. 443 */ 444 if ((so->so_state & SS_ISCONNECTED) == 0) { 445 if (nam != NULL) { 446 error = unp_connect(so, nam, td); 447 if (error) 448 break; /* XXX */ 449 } else { 450 error = ENOTCONN; 451 break; 452 } 453 } 454 455 SOCKBUF_LOCK(&so->so_snd); 456 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 457 SOCKBUF_UNLOCK(&so->so_snd); 458 error = EPIPE; 459 break; 460 } 461 if (unp->unp_conn == NULL) 462 panic("uipc_send connected but no connection?"); 463 so2 = unp->unp_conn->unp_socket; 464 SOCKBUF_LOCK(&so2->so_rcv); 465 /* 466 * Send to paired receive port, and then reduce 467 * send buffer hiwater marks to maintain backpressure. 468 * Wake up readers. 469 */ 470 if (control != NULL) { 471 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 472 control = NULL; 473 } else { 474 sbappend_locked(&so2->so_rcv, m); 475 } 476 so->so_snd.sb_mbmax -= 477 so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt; 478 unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt; 479 newhiwat = so->so_snd.sb_hiwat - 480 (so2->so_rcv.sb_cc - unp->unp_conn->unp_cc); 481 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 482 newhiwat, RLIM_INFINITY); 483 SOCKBUF_UNLOCK(&so->so_snd); 484 unp->unp_conn->unp_cc = so2->so_rcv.sb_cc; 485 sorwakeup_locked(so2); 486 m = NULL; 487 break; 488 489 default: 490 panic("uipc_send unknown socktype"); 491 } 492 493 /* 494 * SEND_EOF is equivalent to a SEND followed by 495 * a SHUTDOWN. 496 */ 497 if (flags & PRUS_EOF) { 498 socantsendmore(so); 499 unp_shutdown(unp); 500 } 501 UNP_UNLOCK(); 502 503 dispose_release: 504 if (control != NULL && error != 0) 505 unp_dispose(control); 506 507 release: 508 if (control != NULL) 509 m_freem(control); 510 if (m != NULL) 511 m_freem(m); 512 return (error); 513 } 514 515 static int 516 uipc_sense(struct socket *so, struct stat *sb) 517 { 518 struct unpcb *unp; 519 struct socket *so2; 520 521 UNP_LOCK(); 522 unp = sotounpcb(so); 523 if (unp == NULL) { 524 UNP_UNLOCK(); 525 return (EINVAL); 526 } 527 sb->st_blksize = so->so_snd.sb_hiwat; 528 if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { 529 so2 = unp->unp_conn->unp_socket; 530 sb->st_blksize += so2->so_rcv.sb_cc; 531 } 532 sb->st_dev = NODEV; 533 if (unp->unp_ino == 0) 534 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 535 sb->st_ino = unp->unp_ino; 536 UNP_UNLOCK(); 537 return (0); 538 } 539 540 static int 541 uipc_shutdown(struct socket *so) 542 { 543 struct unpcb *unp; 544 545 UNP_LOCK(); 546 unp = sotounpcb(so); 547 if (unp == NULL) { 548 UNP_UNLOCK(); 549 return (EINVAL); 550 } 551 socantsendmore(so); 552 unp_shutdown(unp); 553 UNP_UNLOCK(); 554 return (0); 555 } 556 557 static int 558 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 559 { 560 struct unpcb *unp; 561 const struct sockaddr *sa; 562 563 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 564 UNP_LOCK(); 565 unp = sotounpcb(so); 566 if (unp == NULL) { 567 UNP_UNLOCK(); 568 free(*nam, M_SONAME); 569 *nam = NULL; 570 return (EINVAL); 571 } 572 if (unp->unp_addr != NULL) 573 sa = (struct sockaddr *) unp->unp_addr; 574 else 575 sa = &sun_noname; 576 bcopy(sa, *nam, sa->sa_len); 577 UNP_UNLOCK(); 578 return (0); 579 } 580 581 struct pr_usrreqs uipc_usrreqs = { 582 uipc_abort, uipc_accept, uipc_attach, uipc_bind, uipc_connect, 583 uipc_connect2, pru_control_notsupp, uipc_detach, uipc_disconnect, 584 uipc_listen, uipc_peeraddr, uipc_rcvd, pru_rcvoob_notsupp, 585 uipc_send, uipc_sense, uipc_shutdown, uipc_sockaddr, 586 sosend, soreceive, sopoll, pru_sosetlabel_null 587 }; 588 589 int 590 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 591 { 592 struct unpcb *unp; 593 struct xucred xu; 594 int error; 595 596 switch (sopt->sopt_dir) { 597 case SOPT_GET: 598 switch (sopt->sopt_name) { 599 case LOCAL_PEERCRED: 600 error = 0; 601 UNP_LOCK(); 602 unp = sotounpcb(so); 603 if (unp == NULL) { 604 UNP_UNLOCK(); 605 error = EINVAL; 606 break; 607 } 608 if (unp->unp_flags & UNP_HAVEPC) 609 xu = unp->unp_peercred; 610 else { 611 if (so->so_type == SOCK_STREAM) 612 error = ENOTCONN; 613 else 614 error = EINVAL; 615 } 616 UNP_UNLOCK(); 617 if (error == 0) 618 error = sooptcopyout(sopt, &xu, sizeof(xu)); 619 break; 620 default: 621 error = EOPNOTSUPP; 622 break; 623 } 624 break; 625 case SOPT_SET: 626 default: 627 error = EOPNOTSUPP; 628 break; 629 } 630 return (error); 631 } 632 633 /* 634 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 635 * for stream sockets, although the total for sender and receiver is 636 * actually only PIPSIZ. 637 * Datagram sockets really use the sendspace as the maximum datagram size, 638 * and don't really want to reserve the sendspace. Their recvspace should 639 * be large enough for at least one max-size datagram plus address. 640 */ 641 #ifndef PIPSIZ 642 #define PIPSIZ 8192 643 #endif 644 static u_long unpst_sendspace = PIPSIZ; 645 static u_long unpst_recvspace = PIPSIZ; 646 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 647 static u_long unpdg_recvspace = 4*1024; 648 649 static int unp_rights; /* file descriptors in flight */ 650 651 SYSCTL_DECL(_net_local_stream); 652 SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 653 &unpst_sendspace, 0, ""); 654 SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 655 &unpst_recvspace, 0, ""); 656 SYSCTL_DECL(_net_local_dgram); 657 SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 658 &unpdg_sendspace, 0, ""); 659 SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 660 &unpdg_recvspace, 0, ""); 661 SYSCTL_DECL(_net_local); 662 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 663 664 static int 665 unp_attach(struct socket *so) 666 { 667 struct unpcb *unp; 668 int error; 669 670 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 671 switch (so->so_type) { 672 673 case SOCK_STREAM: 674 error = soreserve(so, unpst_sendspace, unpst_recvspace); 675 break; 676 677 case SOCK_DGRAM: 678 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 679 break; 680 681 default: 682 panic("unp_attach"); 683 } 684 if (error) 685 return (error); 686 } 687 unp = uma_zalloc(unp_zone, M_WAITOK | M_ZERO); 688 if (unp == NULL) 689 return (ENOBUFS); 690 LIST_INIT(&unp->unp_refs); 691 unp->unp_socket = so; 692 so->so_pcb = unp; 693 694 UNP_LOCK(); 695 unp->unp_gencnt = ++unp_gencnt; 696 unp_count++; 697 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead 698 : &unp_shead, unp, unp_link); 699 UNP_UNLOCK(); 700 701 return (0); 702 } 703 704 static void 705 unp_detach(struct unpcb *unp) 706 { 707 struct vnode *vp; 708 709 UNP_LOCK_ASSERT(); 710 711 LIST_REMOVE(unp, unp_link); 712 unp->unp_gencnt = ++unp_gencnt; 713 --unp_count; 714 if ((vp = unp->unp_vnode) != NULL) { 715 /* 716 * XXXRW: should v_socket be frobbed only while holding 717 * Giant? 718 */ 719 unp->unp_vnode->v_socket = NULL; 720 unp->unp_vnode = NULL; 721 } 722 if (unp->unp_conn != NULL) 723 unp_disconnect(unp); 724 while (!LIST_EMPTY(&unp->unp_refs)) { 725 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 726 unp_drop(ref, ECONNRESET); 727 } 728 soisdisconnected(unp->unp_socket); 729 unp->unp_socket->so_pcb = NULL; 730 if (unp_rights) { 731 /* 732 * Normally the receive buffer is flushed later, 733 * in sofree, but if our receive buffer holds references 734 * to descriptors that are now garbage, we will dispose 735 * of those descriptor references after the garbage collector 736 * gets them (resulting in a "panic: closef: count < 0"). 737 */ 738 sorflush(unp->unp_socket); 739 unp_gc(); /* Will unlock UNP. */ 740 } else 741 UNP_UNLOCK(); 742 UNP_UNLOCK_ASSERT(); 743 if (unp->unp_addr != NULL) 744 FREE(unp->unp_addr, M_SONAME); 745 uma_zfree(unp_zone, unp); 746 if (vp) { 747 mtx_lock(&Giant); 748 vrele(vp); 749 mtx_unlock(&Giant); 750 } 751 } 752 753 static int 754 unp_bind(struct unpcb *unp, struct sockaddr *nam, struct thread *td) 755 { 756 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 757 struct vnode *vp; 758 struct mount *mp; 759 struct vattr vattr; 760 int error, namelen; 761 struct nameidata nd; 762 char *buf; 763 764 UNP_LOCK_ASSERT(); 765 766 /* 767 * XXXRW: This test-and-set of unp_vnode is non-atomic; the 768 * unlocked read here is fine, but the value of unp_vnode needs 769 * to be tested again after we do all the lookups to see if the 770 * pcb is still unbound? 771 */ 772 if (unp->unp_vnode != NULL) 773 return (EINVAL); 774 775 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 776 if (namelen <= 0) 777 return (EINVAL); 778 779 UNP_UNLOCK(); 780 781 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 782 strlcpy(buf, soun->sun_path, namelen + 1); 783 784 mtx_lock(&Giant); 785 restart: 786 mtx_assert(&Giant, MA_OWNED); 787 NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, 788 buf, td); 789 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 790 error = namei(&nd); 791 if (error) 792 goto done; 793 vp = nd.ni_vp; 794 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 795 NDFREE(&nd, NDF_ONLY_PNBUF); 796 if (nd.ni_dvp == vp) 797 vrele(nd.ni_dvp); 798 else 799 vput(nd.ni_dvp); 800 if (vp != NULL) { 801 vrele(vp); 802 error = EADDRINUSE; 803 goto done; 804 } 805 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 806 if (error) 807 goto done; 808 goto restart; 809 } 810 VATTR_NULL(&vattr); 811 vattr.va_type = VSOCK; 812 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 813 #ifdef MAC 814 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 815 &vattr); 816 #endif 817 if (error == 0) { 818 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 819 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 820 } 821 NDFREE(&nd, NDF_ONLY_PNBUF); 822 vput(nd.ni_dvp); 823 if (error) { 824 vn_finished_write(mp); 825 goto done; 826 } 827 vp = nd.ni_vp; 828 ASSERT_VOP_LOCKED(vp, "unp_bind"); 829 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 830 UNP_LOCK(); 831 vp->v_socket = unp->unp_socket; 832 unp->unp_vnode = vp; 833 unp->unp_addr = soun; 834 UNP_UNLOCK(); 835 VOP_UNLOCK(vp, 0, td); 836 vn_finished_write(mp); 837 done: 838 mtx_unlock(&Giant); 839 free(buf, M_TEMP); 840 UNP_LOCK(); 841 return (error); 842 } 843 844 static int 845 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 846 { 847 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 848 struct vnode *vp; 849 struct socket *so2, *so3; 850 struct unpcb *unp, *unp2, *unp3; 851 int error, len; 852 struct nameidata nd; 853 char buf[SOCK_MAXADDRLEN]; 854 struct sockaddr *sa; 855 856 UNP_LOCK_ASSERT(); 857 unp = sotounpcb(so); 858 859 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 860 if (len <= 0) 861 return (EINVAL); 862 strlcpy(buf, soun->sun_path, len + 1); 863 UNP_UNLOCK(); 864 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 865 mtx_lock(&Giant); 866 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); 867 error = namei(&nd); 868 if (error) 869 vp = NULL; 870 else 871 vp = nd.ni_vp; 872 ASSERT_VOP_LOCKED(vp, "unp_connect"); 873 NDFREE(&nd, NDF_ONLY_PNBUF); 874 if (error) 875 goto bad; 876 877 if (vp->v_type != VSOCK) { 878 error = ENOTSOCK; 879 goto bad; 880 } 881 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 882 if (error) 883 goto bad; 884 mtx_unlock(&Giant); 885 UNP_LOCK(); 886 unp = sotounpcb(so); 887 if (unp == NULL) { 888 error = EINVAL; 889 goto bad2; 890 } 891 so2 = vp->v_socket; 892 if (so2 == NULL) { 893 error = ECONNREFUSED; 894 goto bad2; 895 } 896 if (so->so_type != so2->so_type) { 897 error = EPROTOTYPE; 898 goto bad2; 899 } 900 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 901 if (so2->so_options & SO_ACCEPTCONN) { 902 /* 903 * NB: drop locks here so unp_attach is entered 904 * w/o locks; this avoids a recursive lock 905 * of the head and holding sleep locks across 906 * a (potentially) blocking malloc. 907 */ 908 UNP_UNLOCK(); 909 so3 = sonewconn(so2, 0); 910 UNP_LOCK(); 911 } else 912 so3 = NULL; 913 if (so3 == NULL) { 914 error = ECONNREFUSED; 915 goto bad2; 916 } 917 unp = sotounpcb(so); 918 unp2 = sotounpcb(so2); 919 unp3 = sotounpcb(so3); 920 if (unp2->unp_addr != NULL) { 921 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 922 unp3->unp_addr = (struct sockaddr_un *) sa; 923 sa = NULL; 924 } 925 /* 926 * unp_peercred management: 927 * 928 * The connecter's (client's) credentials are copied 929 * from its process structure at the time of connect() 930 * (which is now). 931 */ 932 cru2x(td->td_ucred, &unp3->unp_peercred); 933 unp3->unp_flags |= UNP_HAVEPC; 934 /* 935 * The receiver's (server's) credentials are copied 936 * from the unp_peercred member of socket on which the 937 * former called listen(); unp_listen() cached that 938 * process's credentials at that time so we can use 939 * them now. 940 */ 941 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 942 ("unp_connect: listener without cached peercred")); 943 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 944 sizeof(unp->unp_peercred)); 945 unp->unp_flags |= UNP_HAVEPC; 946 #ifdef MAC 947 SOCK_LOCK(so); 948 mac_set_socket_peer_from_socket(so, so3); 949 mac_set_socket_peer_from_socket(so3, so); 950 SOCK_UNLOCK(so); 951 #endif 952 953 so2 = so3; 954 } 955 error = unp_connect2(so, so2); 956 bad2: 957 UNP_UNLOCK(); 958 mtx_lock(&Giant); 959 bad: 960 mtx_assert(&Giant, MA_OWNED); 961 if (vp != NULL) 962 vput(vp); 963 mtx_unlock(&Giant); 964 free(sa, M_SONAME); 965 UNP_LOCK(); 966 return (error); 967 } 968 969 static int 970 unp_connect2(struct socket *so, struct socket *so2) 971 { 972 struct unpcb *unp = sotounpcb(so); 973 struct unpcb *unp2; 974 975 UNP_LOCK_ASSERT(); 976 977 if (so2->so_type != so->so_type) 978 return (EPROTOTYPE); 979 unp2 = sotounpcb(so2); 980 unp->unp_conn = unp2; 981 switch (so->so_type) { 982 983 case SOCK_DGRAM: 984 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 985 soisconnected(so); 986 break; 987 988 case SOCK_STREAM: 989 unp2->unp_conn = unp; 990 soisconnected(so); 991 soisconnected(so2); 992 break; 993 994 default: 995 panic("unp_connect2"); 996 } 997 return (0); 998 } 999 1000 static void 1001 unp_disconnect(struct unpcb *unp) 1002 { 1003 struct unpcb *unp2 = unp->unp_conn; 1004 struct socket *so; 1005 1006 UNP_LOCK_ASSERT(); 1007 1008 if (unp2 == NULL) 1009 return; 1010 unp->unp_conn = NULL; 1011 switch (unp->unp_socket->so_type) { 1012 1013 case SOCK_DGRAM: 1014 LIST_REMOVE(unp, unp_reflink); 1015 so = unp->unp_socket; 1016 SOCK_LOCK(so); 1017 so->so_state &= ~SS_ISCONNECTED; 1018 SOCK_UNLOCK(so); 1019 break; 1020 1021 case SOCK_STREAM: 1022 soisdisconnected(unp->unp_socket); 1023 unp2->unp_conn = NULL; 1024 soisdisconnected(unp2->unp_socket); 1025 break; 1026 } 1027 } 1028 1029 #ifdef notdef 1030 void 1031 unp_abort(struct unpcb *unp) 1032 { 1033 1034 unp_detach(unp); 1035 UNP_UNLOCK_ASSERT(); 1036 } 1037 #endif 1038 1039 /* 1040 * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed 1041 * by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers 1042 * are safe to reference. It first scans the list of struct unpcb's to 1043 * generate a pointer list, then it rescans its list one entry at a time to 1044 * externalize and copyout. It checks the generation number to see if a 1045 * struct unpcb has been reused, and will skip it if so. 1046 */ 1047 static int 1048 unp_pcblist(SYSCTL_HANDLER_ARGS) 1049 { 1050 int error, i, n; 1051 struct unpcb *unp, **unp_list; 1052 unp_gen_t gencnt; 1053 struct xunpgen *xug; 1054 struct unp_head *head; 1055 struct xunpcb *xu; 1056 1057 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1058 1059 /* 1060 * The process of preparing the PCB list is too time-consuming and 1061 * resource-intensive to repeat twice on every request. 1062 */ 1063 if (req->oldptr == NULL) { 1064 n = unp_count; 1065 req->oldidx = 2 * (sizeof *xug) 1066 + (n + n/8) * sizeof(struct xunpcb); 1067 return (0); 1068 } 1069 1070 if (req->newptr != NULL) 1071 return (EPERM); 1072 1073 /* 1074 * OK, now we're committed to doing something. 1075 */ 1076 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1077 UNP_LOCK(); 1078 gencnt = unp_gencnt; 1079 n = unp_count; 1080 UNP_UNLOCK(); 1081 1082 xug->xug_len = sizeof *xug; 1083 xug->xug_count = n; 1084 xug->xug_gen = gencnt; 1085 xug->xug_sogen = so_gencnt; 1086 error = SYSCTL_OUT(req, xug, sizeof *xug); 1087 if (error) { 1088 free(xug, M_TEMP); 1089 return (error); 1090 } 1091 1092 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1093 1094 UNP_LOCK(); 1095 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1096 unp = LIST_NEXT(unp, unp_link)) { 1097 if (unp->unp_gencnt <= gencnt) { 1098 if (cr_cansee(req->td->td_ucred, 1099 unp->unp_socket->so_cred)) 1100 continue; 1101 unp_list[i++] = unp; 1102 } 1103 } 1104 UNP_UNLOCK(); 1105 n = i; /* in case we lost some during malloc */ 1106 1107 error = 0; 1108 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 1109 for (i = 0; i < n; i++) { 1110 unp = unp_list[i]; 1111 if (unp->unp_gencnt <= gencnt) { 1112 xu->xu_len = sizeof *xu; 1113 xu->xu_unpp = unp; 1114 /* 1115 * XXX - need more locking here to protect against 1116 * connect/disconnect races for SMP. 1117 */ 1118 if (unp->unp_addr != NULL) 1119 bcopy(unp->unp_addr, &xu->xu_addr, 1120 unp->unp_addr->sun_len); 1121 if (unp->unp_conn != NULL && 1122 unp->unp_conn->unp_addr != NULL) 1123 bcopy(unp->unp_conn->unp_addr, 1124 &xu->xu_caddr, 1125 unp->unp_conn->unp_addr->sun_len); 1126 bcopy(unp, &xu->xu_unp, sizeof *unp); 1127 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1128 error = SYSCTL_OUT(req, xu, sizeof *xu); 1129 } 1130 } 1131 free(xu, M_TEMP); 1132 if (!error) { 1133 /* 1134 * Give the user an updated idea of our state. 1135 * If the generation differs from what we told 1136 * her before, she knows that something happened 1137 * while we were processing this request, and it 1138 * might be necessary to retry. 1139 */ 1140 xug->xug_gen = unp_gencnt; 1141 xug->xug_sogen = so_gencnt; 1142 xug->xug_count = unp_count; 1143 error = SYSCTL_OUT(req, xug, sizeof *xug); 1144 } 1145 free(unp_list, M_TEMP); 1146 free(xug, M_TEMP); 1147 return (error); 1148 } 1149 1150 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1151 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1152 "List of active local datagram sockets"); 1153 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1154 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1155 "List of active local stream sockets"); 1156 1157 static void 1158 unp_shutdown(struct unpcb *unp) 1159 { 1160 struct socket *so; 1161 1162 UNP_LOCK_ASSERT(); 1163 1164 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1165 (so = unp->unp_conn->unp_socket)) 1166 socantrcvmore(so); 1167 } 1168 1169 static void 1170 unp_drop(struct unpcb *unp, int errno) 1171 { 1172 struct socket *so = unp->unp_socket; 1173 1174 UNP_LOCK_ASSERT(); 1175 1176 so->so_error = errno; 1177 unp_disconnect(unp); 1178 } 1179 1180 #ifdef notdef 1181 void 1182 unp_drain(void) 1183 { 1184 1185 } 1186 #endif 1187 1188 static void 1189 unp_freerights(struct file **rp, int fdcount) 1190 { 1191 int i; 1192 struct file *fp; 1193 1194 for (i = 0; i < fdcount; i++) { 1195 fp = *rp; 1196 /* 1197 * zero the pointer before calling 1198 * unp_discard since it may end up 1199 * in unp_gc().. 1200 */ 1201 *rp++ = 0; 1202 unp_discard(fp); 1203 } 1204 } 1205 1206 int 1207 unp_externalize(struct mbuf *control, struct mbuf **controlp) 1208 { 1209 struct thread *td = curthread; /* XXX */ 1210 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1211 int i; 1212 int *fdp; 1213 struct file **rp; 1214 struct file *fp; 1215 void *data; 1216 socklen_t clen = control->m_len, datalen; 1217 int error, newfds; 1218 int f; 1219 u_int newlen; 1220 1221 UNP_UNLOCK_ASSERT(); 1222 1223 error = 0; 1224 if (controlp != NULL) /* controlp == NULL => free control messages */ 1225 *controlp = NULL; 1226 1227 while (cm != NULL) { 1228 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1229 error = EINVAL; 1230 break; 1231 } 1232 1233 data = CMSG_DATA(cm); 1234 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1235 1236 if (cm->cmsg_level == SOL_SOCKET 1237 && cm->cmsg_type == SCM_RIGHTS) { 1238 newfds = datalen / sizeof(struct file *); 1239 rp = data; 1240 1241 /* If we're not outputting the descriptors free them. */ 1242 if (error || controlp == NULL) { 1243 unp_freerights(rp, newfds); 1244 goto next; 1245 } 1246 FILEDESC_LOCK(td->td_proc->p_fd); 1247 /* if the new FD's will not fit free them. */ 1248 if (!fdavail(td, newfds)) { 1249 FILEDESC_UNLOCK(td->td_proc->p_fd); 1250 error = EMSGSIZE; 1251 unp_freerights(rp, newfds); 1252 goto next; 1253 } 1254 /* 1255 * now change each pointer to an fd in the global 1256 * table to an integer that is the index to the 1257 * local fd table entry that we set up to point 1258 * to the global one we are transferring. 1259 */ 1260 newlen = newfds * sizeof(int); 1261 *controlp = sbcreatecontrol(NULL, newlen, 1262 SCM_RIGHTS, SOL_SOCKET); 1263 if (*controlp == NULL) { 1264 FILEDESC_UNLOCK(td->td_proc->p_fd); 1265 error = E2BIG; 1266 unp_freerights(rp, newfds); 1267 goto next; 1268 } 1269 1270 fdp = (int *) 1271 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1272 for (i = 0; i < newfds; i++) { 1273 if (fdalloc(td, 0, &f)) 1274 panic("unp_externalize fdalloc failed"); 1275 fp = *rp++; 1276 td->td_proc->p_fd->fd_ofiles[f] = fp; 1277 FILE_LOCK(fp); 1278 fp->f_msgcount--; 1279 FILE_UNLOCK(fp); 1280 unp_rights--; 1281 *fdp++ = f; 1282 } 1283 FILEDESC_UNLOCK(td->td_proc->p_fd); 1284 } else { /* We can just copy anything else across */ 1285 if (error || controlp == NULL) 1286 goto next; 1287 *controlp = sbcreatecontrol(NULL, datalen, 1288 cm->cmsg_type, cm->cmsg_level); 1289 if (*controlp == NULL) { 1290 error = ENOBUFS; 1291 goto next; 1292 } 1293 bcopy(data, 1294 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1295 datalen); 1296 } 1297 1298 controlp = &(*controlp)->m_next; 1299 1300 next: 1301 if (CMSG_SPACE(datalen) < clen) { 1302 clen -= CMSG_SPACE(datalen); 1303 cm = (struct cmsghdr *) 1304 ((caddr_t)cm + CMSG_SPACE(datalen)); 1305 } else { 1306 clen = 0; 1307 cm = NULL; 1308 } 1309 } 1310 1311 m_freem(control); 1312 1313 return (error); 1314 } 1315 1316 void 1317 unp_init(void) 1318 { 1319 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1320 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 1321 if (unp_zone == NULL) 1322 panic("unp_init"); 1323 uma_zone_set_max(unp_zone, nmbclusters); 1324 LIST_INIT(&unp_dhead); 1325 LIST_INIT(&unp_shead); 1326 1327 UNP_LOCK_INIT(); 1328 } 1329 1330 static int 1331 unp_internalize(struct mbuf **controlp, struct thread *td) 1332 { 1333 struct mbuf *control = *controlp; 1334 struct proc *p = td->td_proc; 1335 struct filedesc *fdescp = p->p_fd; 1336 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1337 struct cmsgcred *cmcred; 1338 struct file **rp; 1339 struct file *fp; 1340 struct timeval *tv; 1341 int i, fd, *fdp; 1342 void *data; 1343 socklen_t clen = control->m_len, datalen; 1344 int error, oldfds; 1345 u_int newlen; 1346 1347 UNP_UNLOCK_ASSERT(); 1348 1349 error = 0; 1350 *controlp = NULL; 1351 1352 while (cm != NULL) { 1353 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1354 || cm->cmsg_len > clen) { 1355 error = EINVAL; 1356 goto out; 1357 } 1358 1359 data = CMSG_DATA(cm); 1360 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1361 1362 switch (cm->cmsg_type) { 1363 /* 1364 * Fill in credential information. 1365 */ 1366 case SCM_CREDS: 1367 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1368 SCM_CREDS, SOL_SOCKET); 1369 if (*controlp == NULL) { 1370 error = ENOBUFS; 1371 goto out; 1372 } 1373 1374 cmcred = (struct cmsgcred *) 1375 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1376 cmcred->cmcred_pid = p->p_pid; 1377 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1378 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1379 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1380 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1381 CMGROUP_MAX); 1382 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1383 cmcred->cmcred_groups[i] = 1384 td->td_ucred->cr_groups[i]; 1385 break; 1386 1387 case SCM_RIGHTS: 1388 oldfds = datalen / sizeof (int); 1389 /* 1390 * check that all the FDs passed in refer to legal files 1391 * If not, reject the entire operation. 1392 */ 1393 fdp = data; 1394 FILEDESC_LOCK(fdescp); 1395 for (i = 0; i < oldfds; i++) { 1396 fd = *fdp++; 1397 if ((unsigned)fd >= fdescp->fd_nfiles || 1398 fdescp->fd_ofiles[fd] == NULL) { 1399 FILEDESC_UNLOCK(fdescp); 1400 error = EBADF; 1401 goto out; 1402 } 1403 fp = fdescp->fd_ofiles[fd]; 1404 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1405 FILEDESC_UNLOCK(fdescp); 1406 error = EOPNOTSUPP; 1407 goto out; 1408 } 1409 1410 } 1411 /* 1412 * Now replace the integer FDs with pointers to 1413 * the associated global file table entry.. 1414 */ 1415 newlen = oldfds * sizeof(struct file *); 1416 *controlp = sbcreatecontrol(NULL, newlen, 1417 SCM_RIGHTS, SOL_SOCKET); 1418 if (*controlp == NULL) { 1419 FILEDESC_UNLOCK(fdescp); 1420 error = E2BIG; 1421 goto out; 1422 } 1423 1424 fdp = data; 1425 rp = (struct file **) 1426 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1427 for (i = 0; i < oldfds; i++) { 1428 fp = fdescp->fd_ofiles[*fdp++]; 1429 *rp++ = fp; 1430 FILE_LOCK(fp); 1431 fp->f_count++; 1432 fp->f_msgcount++; 1433 FILE_UNLOCK(fp); 1434 unp_rights++; 1435 } 1436 FILEDESC_UNLOCK(fdescp); 1437 break; 1438 1439 case SCM_TIMESTAMP: 1440 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1441 SCM_TIMESTAMP, SOL_SOCKET); 1442 if (*controlp == NULL) { 1443 error = ENOBUFS; 1444 goto out; 1445 } 1446 tv = (struct timeval *) 1447 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1448 microtime(tv); 1449 break; 1450 1451 default: 1452 error = EINVAL; 1453 goto out; 1454 } 1455 1456 controlp = &(*controlp)->m_next; 1457 1458 if (CMSG_SPACE(datalen) < clen) { 1459 clen -= CMSG_SPACE(datalen); 1460 cm = (struct cmsghdr *) 1461 ((caddr_t)cm + CMSG_SPACE(datalen)); 1462 } else { 1463 clen = 0; 1464 cm = NULL; 1465 } 1466 } 1467 1468 out: 1469 m_freem(control); 1470 1471 return (error); 1472 } 1473 1474 /* 1475 * unp_defer is thread-local during garbage collection, and does not require 1476 * explicit synchronization. unp_gcing prevents other threads from entering 1477 * garbage collection, and perhaps should be an sx lock instead. 1478 */ 1479 static int unp_defer, unp_gcing; 1480 1481 static void 1482 unp_gc(void) 1483 { 1484 struct file *fp, *nextfp; 1485 struct socket *so; 1486 struct file **extra_ref, **fpp; 1487 int nunref, i; 1488 int nfiles_snap; 1489 int nfiles_slack = 20; 1490 1491 UNP_LOCK_ASSERT(); 1492 1493 if (unp_gcing) { 1494 UNP_UNLOCK(); 1495 return; 1496 } 1497 unp_gcing = 1; 1498 unp_defer = 0; 1499 UNP_UNLOCK(); 1500 /* 1501 * before going through all this, set all FDs to 1502 * be NOT defered and NOT externally accessible 1503 */ 1504 sx_slock(&filelist_lock); 1505 LIST_FOREACH(fp, &filehead, f_list) 1506 fp->f_gcflag &= ~(FMARK|FDEFER); 1507 do { 1508 LIST_FOREACH(fp, &filehead, f_list) { 1509 FILE_LOCK(fp); 1510 /* 1511 * If the file is not open, skip it 1512 */ 1513 if (fp->f_count == 0) { 1514 FILE_UNLOCK(fp); 1515 continue; 1516 } 1517 /* 1518 * If we already marked it as 'defer' in a 1519 * previous pass, then try process it this time 1520 * and un-mark it 1521 */ 1522 if (fp->f_gcflag & FDEFER) { 1523 fp->f_gcflag &= ~FDEFER; 1524 unp_defer--; 1525 } else { 1526 /* 1527 * if it's not defered, then check if it's 1528 * already marked.. if so skip it 1529 */ 1530 if (fp->f_gcflag & FMARK) { 1531 FILE_UNLOCK(fp); 1532 continue; 1533 } 1534 /* 1535 * If all references are from messages 1536 * in transit, then skip it. it's not 1537 * externally accessible. 1538 */ 1539 if (fp->f_count == fp->f_msgcount) { 1540 FILE_UNLOCK(fp); 1541 continue; 1542 } 1543 /* 1544 * If it got this far then it must be 1545 * externally accessible. 1546 */ 1547 fp->f_gcflag |= FMARK; 1548 } 1549 /* 1550 * either it was defered, or it is externally 1551 * accessible and not already marked so. 1552 * Now check if it is possibly one of OUR sockets. 1553 */ 1554 if (fp->f_type != DTYPE_SOCKET || 1555 (so = fp->f_data) == NULL) { 1556 FILE_UNLOCK(fp); 1557 continue; 1558 } 1559 FILE_UNLOCK(fp); 1560 if (so->so_proto->pr_domain != &localdomain || 1561 (so->so_proto->pr_flags&PR_RIGHTS) == 0) 1562 continue; 1563 #ifdef notdef 1564 if (so->so_rcv.sb_flags & SB_LOCK) { 1565 /* 1566 * This is problematical; it's not clear 1567 * we need to wait for the sockbuf to be 1568 * unlocked (on a uniprocessor, at least), 1569 * and it's also not clear what to do 1570 * if sbwait returns an error due to receipt 1571 * of a signal. If sbwait does return 1572 * an error, we'll go into an infinite 1573 * loop. Delete all of this for now. 1574 */ 1575 (void) sbwait(&so->so_rcv); 1576 goto restart; 1577 } 1578 #endif 1579 /* 1580 * So, Ok, it's one of our sockets and it IS externally 1581 * accessible (or was defered). Now we look 1582 * to see if we hold any file descriptors in its 1583 * message buffers. Follow those links and mark them 1584 * as accessible too. 1585 */ 1586 SOCKBUF_LOCK(&so->so_rcv); 1587 unp_scan(so->so_rcv.sb_mb, unp_mark); 1588 SOCKBUF_UNLOCK(&so->so_rcv); 1589 } 1590 } while (unp_defer); 1591 sx_sunlock(&filelist_lock); 1592 /* 1593 * We grab an extra reference to each of the file table entries 1594 * that are not otherwise accessible and then free the rights 1595 * that are stored in messages on them. 1596 * 1597 * The bug in the orginal code is a little tricky, so I'll describe 1598 * what's wrong with it here. 1599 * 1600 * It is incorrect to simply unp_discard each entry for f_msgcount 1601 * times -- consider the case of sockets A and B that contain 1602 * references to each other. On a last close of some other socket, 1603 * we trigger a gc since the number of outstanding rights (unp_rights) 1604 * is non-zero. If during the sweep phase the gc code un_discards, 1605 * we end up doing a (full) closef on the descriptor. A closef on A 1606 * results in the following chain. Closef calls soo_close, which 1607 * calls soclose. Soclose calls first (through the switch 1608 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1609 * returns because the previous instance had set unp_gcing, and 1610 * we return all the way back to soclose, which marks the socket 1611 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1612 * to free up the rights that are queued in messages on the socket A, 1613 * i.e., the reference on B. The sorflush calls via the dom_dispose 1614 * switch unp_dispose, which unp_scans with unp_discard. This second 1615 * instance of unp_discard just calls closef on B. 1616 * 1617 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1618 * which results in another closef on A. Unfortunately, A is already 1619 * being closed, and the descriptor has already been marked with 1620 * SS_NOFDREF, and soclose panics at this point. 1621 * 1622 * Here, we first take an extra reference to each inaccessible 1623 * descriptor. Then, we call sorflush ourself, since we know 1624 * it is a Unix domain socket anyhow. After we destroy all the 1625 * rights carried in messages, we do a last closef to get rid 1626 * of our extra reference. This is the last close, and the 1627 * unp_detach etc will shut down the socket. 1628 * 1629 * 91/09/19, bsy@cs.cmu.edu 1630 */ 1631 again: 1632 nfiles_snap = nfiles + nfiles_slack; /* some slack */ 1633 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 1634 M_WAITOK); 1635 sx_slock(&filelist_lock); 1636 if (nfiles_snap < nfiles) { 1637 sx_sunlock(&filelist_lock); 1638 free(extra_ref, M_TEMP); 1639 nfiles_slack += 20; 1640 goto again; 1641 } 1642 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 1643 fp != NULL; fp = nextfp) { 1644 nextfp = LIST_NEXT(fp, f_list); 1645 FILE_LOCK(fp); 1646 /* 1647 * If it's not open, skip it 1648 */ 1649 if (fp->f_count == 0) { 1650 FILE_UNLOCK(fp); 1651 continue; 1652 } 1653 /* 1654 * If all refs are from msgs, and it's not marked accessible 1655 * then it must be referenced from some unreachable cycle 1656 * of (shut-down) FDs, so include it in our 1657 * list of FDs to remove 1658 */ 1659 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 1660 *fpp++ = fp; 1661 nunref++; 1662 fp->f_count++; 1663 } 1664 FILE_UNLOCK(fp); 1665 } 1666 sx_sunlock(&filelist_lock); 1667 /* 1668 * for each FD on our hit list, do the following two things 1669 */ 1670 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1671 struct file *tfp = *fpp; 1672 FILE_LOCK(tfp); 1673 if (tfp->f_type == DTYPE_SOCKET && 1674 tfp->f_data != NULL) { 1675 FILE_UNLOCK(tfp); 1676 sorflush(tfp->f_data); 1677 } else { 1678 FILE_UNLOCK(tfp); 1679 } 1680 } 1681 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) 1682 closef(*fpp, (struct thread *) NULL); 1683 free(extra_ref, M_TEMP); 1684 unp_gcing = 0; 1685 1686 UNP_UNLOCK_ASSERT(); 1687 } 1688 1689 void 1690 unp_dispose(struct mbuf *m) 1691 { 1692 1693 if (m) 1694 unp_scan(m, unp_discard); 1695 } 1696 1697 static int 1698 unp_listen(struct socket *so, struct unpcb *unp, struct thread *td) 1699 { 1700 int error; 1701 1702 UNP_LOCK_ASSERT(); 1703 1704 SOCK_LOCK(so); 1705 error = solisten_proto_check(so); 1706 if (error == 0) { 1707 cru2x(td->td_ucred, &unp->unp_peercred); 1708 unp->unp_flags |= UNP_HAVEPCCACHED; 1709 solisten_proto(so); 1710 } 1711 SOCK_UNLOCK(so); 1712 return (error); 1713 } 1714 1715 static void 1716 unp_scan(struct mbuf *m0, void (*op)(struct file *)) 1717 { 1718 struct mbuf *m; 1719 struct file **rp; 1720 struct cmsghdr *cm; 1721 void *data; 1722 int i; 1723 socklen_t clen, datalen; 1724 int qfds; 1725 1726 while (m0 != NULL) { 1727 for (m = m0; m; m = m->m_next) { 1728 if (m->m_type != MT_CONTROL) 1729 continue; 1730 1731 cm = mtod(m, struct cmsghdr *); 1732 clen = m->m_len; 1733 1734 while (cm != NULL) { 1735 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 1736 break; 1737 1738 data = CMSG_DATA(cm); 1739 datalen = (caddr_t)cm + cm->cmsg_len 1740 - (caddr_t)data; 1741 1742 if (cm->cmsg_level == SOL_SOCKET && 1743 cm->cmsg_type == SCM_RIGHTS) { 1744 qfds = datalen / sizeof (struct file *); 1745 rp = data; 1746 for (i = 0; i < qfds; i++) 1747 (*op)(*rp++); 1748 } 1749 1750 if (CMSG_SPACE(datalen) < clen) { 1751 clen -= CMSG_SPACE(datalen); 1752 cm = (struct cmsghdr *) 1753 ((caddr_t)cm + CMSG_SPACE(datalen)); 1754 } else { 1755 clen = 0; 1756 cm = NULL; 1757 } 1758 } 1759 } 1760 m0 = m0->m_act; 1761 } 1762 } 1763 1764 static void 1765 unp_mark(struct file *fp) 1766 { 1767 if (fp->f_gcflag & FMARK) 1768 return; 1769 unp_defer++; 1770 fp->f_gcflag |= (FMARK|FDEFER); 1771 } 1772 1773 static void 1774 unp_discard(struct file *fp) 1775 { 1776 FILE_LOCK(fp); 1777 fp->f_msgcount--; 1778 unp_rights--; 1779 FILE_UNLOCK(fp); 1780 (void) closef(fp, (struct thread *)NULL); 1781 }
Cache object: fb50c37a5d7ad627be10aaa0285ab474
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