1 /* 2 * Copyright 2004 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("$FreeBSD$"); 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 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 SOCK_LOCK(so); 144 sotryfree(so); 145 return (0); 146 } 147 148 static int 149 uipc_accept(struct socket *so, struct sockaddr **nam) 150 { 151 struct unpcb *unp; 152 const struct sockaddr *sa; 153 154 /* 155 * Pass back name of connected socket, 156 * if it was bound and we are still connected 157 * (our peer may have closed already!). 158 */ 159 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 160 UNP_LOCK(); 161 unp = sotounpcb(so); 162 if (unp == NULL) { 163 UNP_UNLOCK(); 164 free(*nam, M_SONAME); 165 *nam = NULL; 166 return (EINVAL); 167 } 168 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL) 169 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 170 else 171 sa = &sun_noname; 172 bcopy(sa, *nam, sa->sa_len); 173 UNP_UNLOCK(); 174 return (0); 175 } 176 177 static int 178 uipc_attach(struct socket *so, int proto, struct thread *td) 179 { 180 struct unpcb *unp = sotounpcb(so); 181 182 if (unp != NULL) 183 return (EISCONN); 184 return (unp_attach(so)); 185 } 186 187 static int 188 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 189 { 190 struct unpcb *unp; 191 int error; 192 193 UNP_LOCK(); 194 unp = sotounpcb(so); 195 if (unp == NULL) { 196 UNP_UNLOCK(); 197 return (EINVAL); 198 } 199 error = unp_bind(unp, nam, td); 200 UNP_UNLOCK(); 201 return (error); 202 } 203 204 static int 205 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 206 { 207 struct unpcb *unp; 208 int error; 209 210 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 211 212 UNP_LOCK(); 213 unp = sotounpcb(so); 214 if (unp == NULL) { 215 UNP_UNLOCK(); 216 return (EINVAL); 217 } 218 error = unp_connect(so, nam, td); 219 UNP_UNLOCK(); 220 return (error); 221 } 222 223 int 224 uipc_connect2(struct socket *so1, struct socket *so2) 225 { 226 struct unpcb *unp; 227 int error; 228 229 UNP_LOCK(); 230 unp = sotounpcb(so1); 231 if (unp == NULL) { 232 UNP_UNLOCK(); 233 return (EINVAL); 234 } 235 error = unp_connect2(so1, so2); 236 UNP_UNLOCK(); 237 return (error); 238 } 239 240 /* control is EOPNOTSUPP */ 241 242 static int 243 uipc_detach(struct socket *so) 244 { 245 struct unpcb *unp; 246 247 UNP_LOCK(); 248 unp = sotounpcb(so); 249 if (unp == NULL) { 250 UNP_UNLOCK(); 251 return (EINVAL); 252 } 253 unp_detach(unp); 254 UNP_UNLOCK_ASSERT(); 255 return (0); 256 } 257 258 static int 259 uipc_disconnect(struct socket *so) 260 { 261 struct unpcb *unp; 262 263 UNP_LOCK(); 264 unp = sotounpcb(so); 265 if (unp == NULL) { 266 UNP_UNLOCK(); 267 return (EINVAL); 268 } 269 unp_disconnect(unp); 270 UNP_UNLOCK(); 271 return (0); 272 } 273 274 static int 275 uipc_listen(struct socket *so, struct thread *td) 276 { 277 struct unpcb *unp; 278 int error; 279 280 UNP_LOCK(); 281 unp = sotounpcb(so); 282 if (unp == NULL || unp->unp_vnode == NULL) { 283 UNP_UNLOCK(); 284 return (EINVAL); 285 } 286 error = unp_listen(unp, td); 287 UNP_UNLOCK(); 288 return (error); 289 } 290 291 static int 292 uipc_peeraddr(struct socket *so, struct sockaddr **nam) 293 { 294 struct unpcb *unp; 295 const struct sockaddr *sa; 296 297 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 298 UNP_LOCK(); 299 unp = sotounpcb(so); 300 if (unp == NULL) { 301 UNP_UNLOCK(); 302 free(*nam, M_SONAME); 303 *nam = NULL; 304 return (EINVAL); 305 } 306 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr!= NULL) 307 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 308 else { 309 /* 310 * XXX: It seems that this test always fails even when 311 * connection is established. So, this else clause is 312 * added as workaround to return PF_LOCAL sockaddr. 313 */ 314 sa = &sun_noname; 315 } 316 bcopy(sa, *nam, sa->sa_len); 317 UNP_UNLOCK(); 318 return (0); 319 } 320 321 static int 322 uipc_rcvd(struct socket *so, int flags) 323 { 324 struct unpcb *unp; 325 struct socket *so2; 326 u_long newhiwat; 327 328 UNP_LOCK(); 329 unp = sotounpcb(so); 330 if (unp == NULL) { 331 UNP_UNLOCK(); 332 return (EINVAL); 333 } 334 switch (so->so_type) { 335 case SOCK_DGRAM: 336 panic("uipc_rcvd DGRAM?"); 337 /*NOTREACHED*/ 338 339 case SOCK_STREAM: 340 if (unp->unp_conn == NULL) 341 break; 342 so2 = unp->unp_conn->unp_socket; 343 SOCKBUF_LOCK(&so2->so_snd); 344 SOCKBUF_LOCK(&so->so_rcv); 345 /* 346 * Adjust backpressure on sender 347 * and wakeup any waiting to write. 348 */ 349 so2->so_snd.sb_mbmax += unp->unp_mbcnt - so->so_rcv.sb_mbcnt; 350 unp->unp_mbcnt = so->so_rcv.sb_mbcnt; 351 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - 352 so->so_rcv.sb_cc; 353 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, 354 newhiwat, RLIM_INFINITY); 355 unp->unp_cc = so->so_rcv.sb_cc; 356 SOCKBUF_UNLOCK(&so->so_rcv); 357 sowwakeup_locked(so2); 358 break; 359 360 default: 361 panic("uipc_rcvd unknown socktype"); 362 } 363 UNP_UNLOCK(); 364 return (0); 365 } 366 367 /* pru_rcvoob is EOPNOTSUPP */ 368 369 static int 370 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 371 struct mbuf *control, struct thread *td) 372 { 373 int error = 0; 374 struct unpcb *unp; 375 struct socket *so2; 376 u_long newhiwat; 377 378 unp = sotounpcb(so); 379 if (unp == NULL) { 380 error = EINVAL; 381 goto release; 382 } 383 if (flags & PRUS_OOB) { 384 error = EOPNOTSUPP; 385 goto release; 386 } 387 388 if (control != NULL && (error = unp_internalize(&control, td))) 389 goto release; 390 391 UNP_LOCK(); 392 unp = sotounpcb(so); 393 if (unp == NULL) { 394 UNP_UNLOCK(); 395 error = EINVAL; 396 goto dispose_release; 397 } 398 399 switch (so->so_type) { 400 case SOCK_DGRAM: 401 { 402 const struct sockaddr *from; 403 404 if (nam != NULL) { 405 if (unp->unp_conn != NULL) { 406 error = EISCONN; 407 break; 408 } 409 error = unp_connect(so, nam, td); 410 if (error) 411 break; 412 } else { 413 if (unp->unp_conn == NULL) { 414 error = ENOTCONN; 415 break; 416 } 417 } 418 so2 = unp->unp_conn->unp_socket; 419 if (unp->unp_addr != NULL) 420 from = (struct sockaddr *)unp->unp_addr; 421 else 422 from = &sun_noname; 423 SOCKBUF_LOCK(&so2->so_rcv); 424 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 425 sorwakeup_locked(so2); 426 m = NULL; 427 control = NULL; 428 } else { 429 SOCKBUF_UNLOCK(&so2->so_rcv); 430 error = ENOBUFS; 431 } 432 if (nam != NULL) 433 unp_disconnect(unp); 434 break; 435 } 436 437 case SOCK_STREAM: 438 /* Connect if not connected yet. */ 439 /* 440 * Note: A better implementation would complain 441 * if not equal to the peer's address. 442 */ 443 if ((so->so_state & SS_ISCONNECTED) == 0) { 444 if (nam != NULL) { 445 error = unp_connect(so, nam, td); 446 if (error) 447 break; /* XXX */ 448 } else { 449 error = ENOTCONN; 450 break; 451 } 452 } 453 454 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 455 error = EPIPE; 456 break; 457 } 458 if (unp->unp_conn == NULL) 459 panic("uipc_send connected but no connection?"); 460 so2 = unp->unp_conn->unp_socket; 461 SOCKBUF_LOCK(&so2->so_rcv); 462 /* 463 * Send to paired receive port, and then reduce 464 * send buffer hiwater marks to maintain backpressure. 465 * Wake up readers. 466 */ 467 if (control != NULL) { 468 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 469 control = NULL; 470 } else { 471 sbappend_locked(&so2->so_rcv, m); 472 } 473 so->so_snd.sb_mbmax -= 474 so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt; 475 unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt; 476 newhiwat = so->so_snd.sb_hiwat - 477 (so2->so_rcv.sb_cc - unp->unp_conn->unp_cc); 478 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 479 newhiwat, RLIM_INFINITY); 480 unp->unp_conn->unp_cc = so2->so_rcv.sb_cc; 481 sorwakeup_locked(so2); 482 m = NULL; 483 break; 484 485 default: 486 panic("uipc_send unknown socktype"); 487 } 488 489 /* 490 * SEND_EOF is equivalent to a SEND followed by 491 * a SHUTDOWN. 492 */ 493 if (flags & PRUS_EOF) { 494 socantsendmore(so); 495 unp_shutdown(unp); 496 } 497 UNP_UNLOCK(); 498 499 dispose_release: 500 if (control != NULL && error != 0) 501 unp_dispose(control); 502 503 release: 504 if (control != NULL) 505 m_freem(control); 506 if (m != NULL) 507 m_freem(m); 508 return (error); 509 } 510 511 static int 512 uipc_sense(struct socket *so, struct stat *sb) 513 { 514 struct unpcb *unp; 515 struct socket *so2; 516 517 UNP_LOCK(); 518 unp = sotounpcb(so); 519 if (unp == NULL) { 520 UNP_UNLOCK(); 521 return (EINVAL); 522 } 523 sb->st_blksize = so->so_snd.sb_hiwat; 524 if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { 525 so2 = unp->unp_conn->unp_socket; 526 sb->st_blksize += so2->so_rcv.sb_cc; 527 } 528 sb->st_dev = NODEV; 529 if (unp->unp_ino == 0) 530 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 531 sb->st_ino = unp->unp_ino; 532 UNP_UNLOCK(); 533 return (0); 534 } 535 536 static int 537 uipc_shutdown(struct socket *so) 538 { 539 struct unpcb *unp; 540 541 UNP_LOCK(); 542 unp = sotounpcb(so); 543 if (unp == NULL) { 544 UNP_UNLOCK(); 545 return (EINVAL); 546 } 547 socantsendmore(so); 548 unp_shutdown(unp); 549 UNP_UNLOCK(); 550 return (0); 551 } 552 553 static int 554 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 555 { 556 struct unpcb *unp; 557 const struct sockaddr *sa; 558 559 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 560 UNP_LOCK(); 561 unp = sotounpcb(so); 562 if (unp == NULL) { 563 UNP_UNLOCK(); 564 free(*nam, M_SONAME); 565 *nam = NULL; 566 return (EINVAL); 567 } 568 if (unp->unp_addr != NULL) 569 sa = (struct sockaddr *) unp->unp_addr; 570 else 571 sa = &sun_noname; 572 bcopy(sa, *nam, sa->sa_len); 573 UNP_UNLOCK(); 574 return (0); 575 } 576 577 struct pr_usrreqs uipc_usrreqs = { 578 uipc_abort, uipc_accept, uipc_attach, uipc_bind, uipc_connect, 579 uipc_connect2, pru_control_notsupp, uipc_detach, uipc_disconnect, 580 uipc_listen, uipc_peeraddr, uipc_rcvd, pru_rcvoob_notsupp, 581 uipc_send, uipc_sense, uipc_shutdown, uipc_sockaddr, 582 sosend, soreceive, sopoll, pru_sosetlabel_null 583 }; 584 585 int 586 uipc_ctloutput(so, sopt) 587 struct socket *so; 588 struct sockopt *sopt; 589 { 590 struct unpcb *unp; 591 struct xucred xu; 592 int error; 593 594 switch (sopt->sopt_dir) { 595 case SOPT_GET: 596 switch (sopt->sopt_name) { 597 case LOCAL_PEERCRED: 598 error = 0; 599 UNP_LOCK(); 600 unp = sotounpcb(so); 601 if (unp == NULL) { 602 UNP_UNLOCK(); 603 error = EINVAL; 604 break; 605 } 606 if (unp->unp_flags & UNP_HAVEPC) 607 xu = unp->unp_peercred; 608 else { 609 if (so->so_type == SOCK_STREAM) 610 error = ENOTCONN; 611 else 612 error = EINVAL; 613 } 614 UNP_UNLOCK(); 615 if (error == 0) 616 error = sooptcopyout(sopt, &xu, sizeof(xu)); 617 break; 618 default: 619 error = EOPNOTSUPP; 620 break; 621 } 622 break; 623 case SOPT_SET: 624 default: 625 error = EOPNOTSUPP; 626 break; 627 } 628 return (error); 629 } 630 631 /* 632 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 633 * for stream sockets, although the total for sender and receiver is 634 * actually only PIPSIZ. 635 * Datagram sockets really use the sendspace as the maximum datagram size, 636 * and don't really want to reserve the sendspace. Their recvspace should 637 * be large enough for at least one max-size datagram plus address. 638 */ 639 #ifndef PIPSIZ 640 #define PIPSIZ 8192 641 #endif 642 static u_long unpst_sendspace = PIPSIZ; 643 static u_long unpst_recvspace = PIPSIZ; 644 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 645 static u_long unpdg_recvspace = 4*1024; 646 647 static int unp_rights; /* file descriptors in flight */ 648 649 SYSCTL_DECL(_net_local_stream); 650 SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 651 &unpst_sendspace, 0, ""); 652 SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 653 &unpst_recvspace, 0, ""); 654 SYSCTL_DECL(_net_local_dgram); 655 SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 656 &unpdg_sendspace, 0, ""); 657 SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 658 &unpdg_recvspace, 0, ""); 659 SYSCTL_DECL(_net_local); 660 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 661 662 static int 663 unp_attach(so) 664 struct socket *so; 665 { 666 register struct unpcb *unp; 667 int error; 668 669 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 670 switch (so->so_type) { 671 672 case SOCK_STREAM: 673 error = soreserve(so, unpst_sendspace, unpst_recvspace); 674 break; 675 676 case SOCK_DGRAM: 677 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 678 break; 679 680 default: 681 panic("unp_attach"); 682 } 683 if (error) 684 return (error); 685 } 686 unp = uma_zalloc(unp_zone, M_WAITOK); 687 if (unp == NULL) 688 return (ENOBUFS); 689 bzero(unp, sizeof *unp); 690 LIST_INIT(&unp->unp_refs); 691 unp->unp_socket = so; 692 693 UNP_LOCK(); 694 unp->unp_gencnt = ++unp_gencnt; 695 unp_count++; 696 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead 697 : &unp_shead, unp, unp_link); 698 so->so_pcb = unp; 699 UNP_UNLOCK(); 700 701 return (0); 702 } 703 704 static void 705 unp_detach(unp) 706 register struct unpcb *unp; 707 { 708 struct vnode *vp; 709 710 UNP_LOCK_ASSERT(); 711 712 LIST_REMOVE(unp, unp_link); 713 unp->unp_gencnt = ++unp_gencnt; 714 --unp_count; 715 if ((vp = unp->unp_vnode) != NULL) { 716 /* 717 * XXXRW: should v_socket be frobbed only while holding 718 * Giant? 719 */ 720 unp->unp_vnode->v_socket = NULL; 721 unp->unp_vnode = NULL; 722 } 723 if (unp->unp_conn != NULL) 724 unp_disconnect(unp); 725 while (!LIST_EMPTY(&unp->unp_refs)) { 726 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 727 unp_drop(ref, ECONNRESET); 728 } 729 soisdisconnected(unp->unp_socket); 730 unp->unp_socket->so_pcb = NULL; 731 if (unp_rights) { 732 /* 733 * Normally the receive buffer is flushed later, 734 * in sofree, but if our receive buffer holds references 735 * to descriptors that are now garbage, we will dispose 736 * of those descriptor references after the garbage collector 737 * gets them (resulting in a "panic: closef: count < 0"). 738 */ 739 sorflush(unp->unp_socket); 740 unp_gc(); /* Will unlock UNP. */ 741 } else 742 UNP_UNLOCK(); 743 UNP_UNLOCK_ASSERT(); 744 if (unp->unp_addr != NULL) 745 FREE(unp->unp_addr, M_SONAME); 746 uma_zfree(unp_zone, unp); 747 if (vp) { 748 mtx_lock(&Giant); 749 vrele(vp); 750 mtx_unlock(&Giant); 751 } 752 } 753 754 static int 755 unp_bind(unp, nam, td) 756 struct unpcb *unp; 757 struct sockaddr *nam; 758 struct thread *td; 759 { 760 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 761 struct vnode *vp; 762 struct mount *mp; 763 struct vattr vattr; 764 int error, namelen; 765 struct nameidata nd; 766 char *buf; 767 768 UNP_LOCK_ASSERT(); 769 770 /* 771 * XXXRW: This test-and-set of unp_vnode is non-atomic; the 772 * unlocked read here is fine, but the value of unp_vnode needs 773 * to be tested again after we do all the lookups to see if the 774 * pcb is still unbound? 775 */ 776 if (unp->unp_vnode != NULL) 777 return (EINVAL); 778 779 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 780 if (namelen <= 0) 781 return (EINVAL); 782 783 UNP_UNLOCK(); 784 785 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 786 strlcpy(buf, soun->sun_path, namelen + 1); 787 788 mtx_lock(&Giant); 789 restart: 790 mtx_assert(&Giant, MA_OWNED); 791 NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, 792 buf, td); 793 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 794 error = namei(&nd); 795 if (error) 796 goto done; 797 vp = nd.ni_vp; 798 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 799 NDFREE(&nd, NDF_ONLY_PNBUF); 800 if (nd.ni_dvp == vp) 801 vrele(nd.ni_dvp); 802 else 803 vput(nd.ni_dvp); 804 if (vp != NULL) { 805 vrele(vp); 806 error = EADDRINUSE; 807 goto done; 808 } 809 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 810 if (error) 811 goto done; 812 goto restart; 813 } 814 VATTR_NULL(&vattr); 815 vattr.va_type = VSOCK; 816 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 817 #ifdef MAC 818 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 819 &vattr); 820 #endif 821 if (error == 0) { 822 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 823 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 824 } 825 NDFREE(&nd, NDF_ONLY_PNBUF); 826 vput(nd.ni_dvp); 827 if (error) 828 goto done; 829 vp = nd.ni_vp; 830 ASSERT_VOP_LOCKED(vp, "unp_bind"); 831 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 832 UNP_LOCK(); 833 vp->v_socket = unp->unp_socket; 834 unp->unp_vnode = vp; 835 unp->unp_addr = soun; 836 UNP_UNLOCK(); 837 VOP_UNLOCK(vp, 0, td); 838 vn_finished_write(mp); 839 done: 840 mtx_unlock(&Giant); 841 free(buf, M_TEMP); 842 UNP_LOCK(); 843 return (error); 844 } 845 846 static int 847 unp_connect(so, nam, td) 848 struct socket *so; 849 struct sockaddr *nam; 850 struct thread *td; 851 { 852 register struct sockaddr_un *soun = (struct sockaddr_un *)nam; 853 register struct vnode *vp; 854 register struct socket *so2, *so3; 855 struct unpcb *unp, *unp2, *unp3; 856 int error, len; 857 struct nameidata nd; 858 char buf[SOCK_MAXADDRLEN]; 859 struct sockaddr *sa; 860 861 UNP_LOCK_ASSERT(); 862 unp = sotounpcb(so); 863 864 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 865 if (len <= 0) 866 return (EINVAL); 867 strlcpy(buf, soun->sun_path, len + 1); 868 UNP_UNLOCK(); 869 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 870 mtx_lock(&Giant); 871 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); 872 error = namei(&nd); 873 if (error) 874 vp = NULL; 875 else 876 vp = nd.ni_vp; 877 ASSERT_VOP_LOCKED(vp, "unp_connect"); 878 NDFREE(&nd, NDF_ONLY_PNBUF); 879 if (error) 880 goto bad; 881 882 if (vp->v_type != VSOCK) { 883 error = ENOTSOCK; 884 goto bad; 885 } 886 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 887 if (error) 888 goto bad; 889 mtx_unlock(&Giant); 890 UNP_LOCK(); 891 unp = sotounpcb(so); 892 if (unp == NULL) { 893 /* 894 * XXXRW: Temporary debugging printf. 895 */ 896 printf("unp_connect(): lost race to another thread\n"); 897 error = EINVAL; 898 goto bad2; 899 } 900 so2 = vp->v_socket; 901 if (so2 == NULL) { 902 error = ECONNREFUSED; 903 goto bad2; 904 } 905 if (so->so_type != so2->so_type) { 906 error = EPROTOTYPE; 907 goto bad2; 908 } 909 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 910 if (so2->so_options & SO_ACCEPTCONN) { 911 /* 912 * NB: drop locks here so unp_attach is entered 913 * w/o locks; this avoids a recursive lock 914 * of the head and holding sleep locks across 915 * a (potentially) blocking malloc. 916 */ 917 UNP_UNLOCK(); 918 so3 = sonewconn(so2, 0); 919 UNP_LOCK(); 920 } else 921 so3 = NULL; 922 if (so3 == NULL) { 923 error = ECONNREFUSED; 924 goto bad2; 925 } 926 unp = sotounpcb(so); 927 unp2 = sotounpcb(so2); 928 unp3 = sotounpcb(so3); 929 if (unp2->unp_addr != NULL) { 930 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 931 unp3->unp_addr = (struct sockaddr_un *) sa; 932 sa = NULL; 933 } 934 /* 935 * unp_peercred management: 936 * 937 * The connecter's (client's) credentials are copied 938 * from its process structure at the time of connect() 939 * (which is now). 940 */ 941 cru2x(td->td_ucred, &unp3->unp_peercred); 942 unp3->unp_flags |= UNP_HAVEPC; 943 /* 944 * The receiver's (server's) credentials are copied 945 * from the unp_peercred member of socket on which the 946 * former called listen(); unp_listen() cached that 947 * process's credentials at that time so we can use 948 * them now. 949 */ 950 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 951 ("unp_connect: listener without cached peercred")); 952 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 953 sizeof(unp->unp_peercred)); 954 unp->unp_flags |= UNP_HAVEPC; 955 #ifdef MAC 956 SOCK_LOCK(so); 957 mac_set_socket_peer_from_socket(so, so3); 958 mac_set_socket_peer_from_socket(so3, so); 959 SOCK_UNLOCK(so); 960 #endif 961 962 so2 = so3; 963 } 964 error = unp_connect2(so, so2); 965 bad2: 966 UNP_UNLOCK(); 967 mtx_lock(&Giant); 968 bad: 969 mtx_assert(&Giant, MA_OWNED); 970 if (vp != NULL) 971 vput(vp); 972 mtx_unlock(&Giant); 973 free(sa, M_SONAME); 974 UNP_LOCK(); 975 return (error); 976 } 977 978 static int 979 unp_connect2(so, so2) 980 register struct socket *so; 981 register struct socket *so2; 982 { 983 register struct unpcb *unp = sotounpcb(so); 984 register struct unpcb *unp2; 985 986 UNP_LOCK_ASSERT(); 987 988 if (so2->so_type != so->so_type) 989 return (EPROTOTYPE); 990 unp2 = sotounpcb(so2); 991 unp->unp_conn = unp2; 992 switch (so->so_type) { 993 994 case SOCK_DGRAM: 995 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 996 soisconnected(so); 997 break; 998 999 case SOCK_STREAM: 1000 unp2->unp_conn = unp; 1001 soisconnected(so); 1002 soisconnected(so2); 1003 break; 1004 1005 default: 1006 panic("unp_connect2"); 1007 } 1008 return (0); 1009 } 1010 1011 static void 1012 unp_disconnect(unp) 1013 struct unpcb *unp; 1014 { 1015 register struct unpcb *unp2 = unp->unp_conn; 1016 struct socket *so; 1017 1018 UNP_LOCK_ASSERT(); 1019 1020 if (unp2 == NULL) 1021 return; 1022 unp->unp_conn = NULL; 1023 switch (unp->unp_socket->so_type) { 1024 1025 case SOCK_DGRAM: 1026 LIST_REMOVE(unp, unp_reflink); 1027 so = unp->unp_socket; 1028 SOCK_LOCK(so); 1029 so->so_state &= ~SS_ISCONNECTED; 1030 SOCK_UNLOCK(so); 1031 break; 1032 1033 case SOCK_STREAM: 1034 soisdisconnected(unp->unp_socket); 1035 unp2->unp_conn = NULL; 1036 soisdisconnected(unp2->unp_socket); 1037 break; 1038 } 1039 } 1040 1041 #ifdef notdef 1042 void 1043 unp_abort(unp) 1044 struct unpcb *unp; 1045 { 1046 1047 unp_detach(unp); 1048 UNP_UNLOCK_ASSERT(); 1049 } 1050 #endif 1051 1052 /* 1053 * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed 1054 * by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers 1055 * are safe to reference. It first scans the list of struct unpcb's to 1056 * generate a pointer list, then it rescans its list one entry at a time to 1057 * externalize and copyout. It checks the generation number to see if a 1058 * struct unpcb has been reused, and will skip it if so. 1059 */ 1060 static int 1061 unp_pcblist(SYSCTL_HANDLER_ARGS) 1062 { 1063 int error, i, n; 1064 struct unpcb *unp, **unp_list; 1065 unp_gen_t gencnt; 1066 struct xunpgen *xug; 1067 struct unp_head *head; 1068 struct xunpcb *xu; 1069 1070 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1071 1072 /* 1073 * The process of preparing the PCB list is too time-consuming and 1074 * resource-intensive to repeat twice on every request. 1075 */ 1076 if (req->oldptr == NULL) { 1077 n = unp_count; 1078 req->oldidx = 2 * (sizeof *xug) 1079 + (n + n/8) * sizeof(struct xunpcb); 1080 return (0); 1081 } 1082 1083 if (req->newptr != NULL) 1084 return (EPERM); 1085 1086 /* 1087 * OK, now we're committed to doing something. 1088 */ 1089 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1090 UNP_LOCK(); 1091 gencnt = unp_gencnt; 1092 n = unp_count; 1093 UNP_UNLOCK(); 1094 1095 xug->xug_len = sizeof *xug; 1096 xug->xug_count = n; 1097 xug->xug_gen = gencnt; 1098 xug->xug_sogen = so_gencnt; 1099 error = SYSCTL_OUT(req, xug, sizeof *xug); 1100 if (error) { 1101 free(xug, M_TEMP); 1102 return (error); 1103 } 1104 1105 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1106 1107 UNP_LOCK(); 1108 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1109 unp = LIST_NEXT(unp, unp_link)) { 1110 if (unp->unp_gencnt <= gencnt) { 1111 if (cr_cansee(req->td->td_ucred, 1112 unp->unp_socket->so_cred)) 1113 continue; 1114 unp_list[i++] = unp; 1115 } 1116 } 1117 UNP_UNLOCK(); 1118 n = i; /* in case we lost some during malloc */ 1119 1120 error = 0; 1121 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK); 1122 for (i = 0; i < n; i++) { 1123 unp = unp_list[i]; 1124 if (unp->unp_gencnt <= gencnt) { 1125 xu->xu_len = sizeof *xu; 1126 xu->xu_unpp = unp; 1127 /* 1128 * XXX - need more locking here to protect against 1129 * connect/disconnect races for SMP. 1130 */ 1131 if (unp->unp_addr != NULL) 1132 bcopy(unp->unp_addr, &xu->xu_addr, 1133 unp->unp_addr->sun_len); 1134 if (unp->unp_conn != NULL && 1135 unp->unp_conn->unp_addr != NULL) 1136 bcopy(unp->unp_conn->unp_addr, 1137 &xu->xu_caddr, 1138 unp->unp_conn->unp_addr->sun_len); 1139 bcopy(unp, &xu->xu_unp, sizeof *unp); 1140 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1141 error = SYSCTL_OUT(req, xu, sizeof *xu); 1142 } 1143 } 1144 free(xu, M_TEMP); 1145 if (!error) { 1146 /* 1147 * Give the user an updated idea of our state. 1148 * If the generation differs from what we told 1149 * her before, she knows that something happened 1150 * while we were processing this request, and it 1151 * might be necessary to retry. 1152 */ 1153 xug->xug_gen = unp_gencnt; 1154 xug->xug_sogen = so_gencnt; 1155 xug->xug_count = unp_count; 1156 error = SYSCTL_OUT(req, xug, sizeof *xug); 1157 } 1158 free(unp_list, M_TEMP); 1159 free(xug, M_TEMP); 1160 return (error); 1161 } 1162 1163 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1164 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1165 "List of active local datagram sockets"); 1166 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1167 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1168 "List of active local stream sockets"); 1169 1170 static void 1171 unp_shutdown(unp) 1172 struct unpcb *unp; 1173 { 1174 struct socket *so; 1175 1176 UNP_LOCK_ASSERT(); 1177 1178 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1179 (so = unp->unp_conn->unp_socket)) 1180 socantrcvmore(so); 1181 } 1182 1183 static void 1184 unp_drop(unp, errno) 1185 struct unpcb *unp; 1186 int errno; 1187 { 1188 struct socket *so = unp->unp_socket; 1189 1190 UNP_LOCK_ASSERT(); 1191 1192 so->so_error = errno; 1193 unp_disconnect(unp); 1194 } 1195 1196 #ifdef notdef 1197 void 1198 unp_drain() 1199 { 1200 1201 } 1202 #endif 1203 1204 static void 1205 unp_freerights(rp, fdcount) 1206 struct file **rp; 1207 int fdcount; 1208 { 1209 int i; 1210 struct file *fp; 1211 1212 for (i = 0; i < fdcount; i++) { 1213 fp = *rp; 1214 /* 1215 * zero the pointer before calling 1216 * unp_discard since it may end up 1217 * in unp_gc().. 1218 */ 1219 *rp++ = 0; 1220 unp_discard(fp); 1221 } 1222 } 1223 1224 int 1225 unp_externalize(control, controlp) 1226 struct mbuf *control, **controlp; 1227 { 1228 struct thread *td = curthread; /* XXX */ 1229 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1230 int i; 1231 int *fdp; 1232 struct file **rp; 1233 struct file *fp; 1234 void *data; 1235 socklen_t clen = control->m_len, datalen; 1236 int error, newfds; 1237 int f; 1238 u_int newlen; 1239 1240 UNP_UNLOCK_ASSERT(); 1241 1242 error = 0; 1243 if (controlp != NULL) /* controlp == NULL => free control messages */ 1244 *controlp = NULL; 1245 1246 while (cm != NULL) { 1247 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1248 error = EINVAL; 1249 break; 1250 } 1251 1252 data = CMSG_DATA(cm); 1253 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1254 1255 if (cm->cmsg_level == SOL_SOCKET 1256 && cm->cmsg_type == SCM_RIGHTS) { 1257 newfds = datalen / sizeof(struct file *); 1258 rp = data; 1259 1260 /* If we're not outputting the descriptors free them. */ 1261 if (error || controlp == NULL) { 1262 unp_freerights(rp, newfds); 1263 goto next; 1264 } 1265 FILEDESC_LOCK(td->td_proc->p_fd); 1266 /* if the new FD's will not fit free them. */ 1267 if (!fdavail(td, newfds)) { 1268 FILEDESC_UNLOCK(td->td_proc->p_fd); 1269 error = EMSGSIZE; 1270 unp_freerights(rp, newfds); 1271 goto next; 1272 } 1273 /* 1274 * now change each pointer to an fd in the global 1275 * table to an integer that is the index to the 1276 * local fd table entry that we set up to point 1277 * to the global one we are transferring. 1278 */ 1279 newlen = newfds * sizeof(int); 1280 *controlp = sbcreatecontrol(NULL, newlen, 1281 SCM_RIGHTS, SOL_SOCKET); 1282 if (*controlp == NULL) { 1283 FILEDESC_UNLOCK(td->td_proc->p_fd); 1284 error = E2BIG; 1285 unp_freerights(rp, newfds); 1286 goto next; 1287 } 1288 1289 fdp = (int *) 1290 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1291 for (i = 0; i < newfds; i++) { 1292 if (fdalloc(td, 0, &f)) 1293 panic("unp_externalize fdalloc failed"); 1294 fp = *rp++; 1295 td->td_proc->p_fd->fd_ofiles[f] = fp; 1296 FILE_LOCK(fp); 1297 fp->f_msgcount--; 1298 FILE_UNLOCK(fp); 1299 unp_rights--; 1300 *fdp++ = f; 1301 } 1302 FILEDESC_UNLOCK(td->td_proc->p_fd); 1303 } else { /* We can just copy anything else across */ 1304 if (error || controlp == NULL) 1305 goto next; 1306 *controlp = sbcreatecontrol(NULL, datalen, 1307 cm->cmsg_type, cm->cmsg_level); 1308 if (*controlp == NULL) { 1309 error = ENOBUFS; 1310 goto next; 1311 } 1312 bcopy(data, 1313 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1314 datalen); 1315 } 1316 1317 controlp = &(*controlp)->m_next; 1318 1319 next: 1320 if (CMSG_SPACE(datalen) < clen) { 1321 clen -= CMSG_SPACE(datalen); 1322 cm = (struct cmsghdr *) 1323 ((caddr_t)cm + CMSG_SPACE(datalen)); 1324 } else { 1325 clen = 0; 1326 cm = NULL; 1327 } 1328 } 1329 1330 m_freem(control); 1331 1332 return (error); 1333 } 1334 1335 void 1336 unp_init(void) 1337 { 1338 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1339 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 1340 if (unp_zone == NULL) 1341 panic("unp_init"); 1342 uma_zone_set_max(unp_zone, nmbclusters); 1343 LIST_INIT(&unp_dhead); 1344 LIST_INIT(&unp_shead); 1345 1346 UNP_LOCK_INIT(); 1347 } 1348 1349 static int 1350 unp_internalize(controlp, td) 1351 struct mbuf **controlp; 1352 struct thread *td; 1353 { 1354 struct mbuf *control = *controlp; 1355 struct proc *p = td->td_proc; 1356 struct filedesc *fdescp = p->p_fd; 1357 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1358 struct cmsgcred *cmcred; 1359 struct file **rp; 1360 struct file *fp; 1361 struct timeval *tv; 1362 int i, fd, *fdp; 1363 void *data; 1364 socklen_t clen = control->m_len, datalen; 1365 int error, oldfds; 1366 u_int newlen; 1367 1368 UNP_UNLOCK_ASSERT(); 1369 1370 error = 0; 1371 *controlp = NULL; 1372 1373 while (cm != NULL) { 1374 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1375 || cm->cmsg_len > clen) { 1376 error = EINVAL; 1377 goto out; 1378 } 1379 1380 data = CMSG_DATA(cm); 1381 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1382 1383 switch (cm->cmsg_type) { 1384 /* 1385 * Fill in credential information. 1386 */ 1387 case SCM_CREDS: 1388 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1389 SCM_CREDS, SOL_SOCKET); 1390 if (*controlp == NULL) { 1391 error = ENOBUFS; 1392 goto out; 1393 } 1394 1395 cmcred = (struct cmsgcred *) 1396 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1397 cmcred->cmcred_pid = p->p_pid; 1398 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1399 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1400 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1401 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1402 CMGROUP_MAX); 1403 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1404 cmcred->cmcred_groups[i] = 1405 td->td_ucred->cr_groups[i]; 1406 break; 1407 1408 case SCM_RIGHTS: 1409 oldfds = datalen / sizeof (int); 1410 /* 1411 * check that all the FDs passed in refer to legal files 1412 * If not, reject the entire operation. 1413 */ 1414 fdp = data; 1415 FILEDESC_LOCK(fdescp); 1416 for (i = 0; i < oldfds; i++) { 1417 fd = *fdp++; 1418 if ((unsigned)fd >= fdescp->fd_nfiles || 1419 fdescp->fd_ofiles[fd] == NULL) { 1420 FILEDESC_UNLOCK(fdescp); 1421 error = EBADF; 1422 goto out; 1423 } 1424 fp = fdescp->fd_ofiles[fd]; 1425 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1426 FILEDESC_UNLOCK(fdescp); 1427 error = EOPNOTSUPP; 1428 goto out; 1429 } 1430 1431 } 1432 /* 1433 * Now replace the integer FDs with pointers to 1434 * the associated global file table entry.. 1435 */ 1436 newlen = oldfds * sizeof(struct file *); 1437 *controlp = sbcreatecontrol(NULL, newlen, 1438 SCM_RIGHTS, SOL_SOCKET); 1439 if (*controlp == NULL) { 1440 FILEDESC_UNLOCK(fdescp); 1441 error = E2BIG; 1442 goto out; 1443 } 1444 1445 fdp = data; 1446 rp = (struct file **) 1447 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1448 for (i = 0; i < oldfds; i++) { 1449 fp = fdescp->fd_ofiles[*fdp++]; 1450 *rp++ = fp; 1451 FILE_LOCK(fp); 1452 fp->f_count++; 1453 fp->f_msgcount++; 1454 FILE_UNLOCK(fp); 1455 unp_rights++; 1456 } 1457 FILEDESC_UNLOCK(fdescp); 1458 break; 1459 1460 case SCM_TIMESTAMP: 1461 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1462 SCM_TIMESTAMP, SOL_SOCKET); 1463 if (*controlp == NULL) { 1464 error = ENOBUFS; 1465 goto out; 1466 } 1467 tv = (struct timeval *) 1468 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1469 microtime(tv); 1470 break; 1471 1472 default: 1473 error = EINVAL; 1474 goto out; 1475 } 1476 1477 controlp = &(*controlp)->m_next; 1478 1479 if (CMSG_SPACE(datalen) < clen) { 1480 clen -= CMSG_SPACE(datalen); 1481 cm = (struct cmsghdr *) 1482 ((caddr_t)cm + CMSG_SPACE(datalen)); 1483 } else { 1484 clen = 0; 1485 cm = NULL; 1486 } 1487 } 1488 1489 out: 1490 m_freem(control); 1491 1492 return (error); 1493 } 1494 1495 /* 1496 * unp_defer is thread-local during garbage collection, and does not require 1497 * explicit synchronization. unp_gcing prevents other threads from entering 1498 * garbage collection, and perhaps should be an sx lock instead. 1499 */ 1500 static int unp_defer, unp_gcing; 1501 1502 static void 1503 unp_gc() 1504 { 1505 register struct file *fp, *nextfp; 1506 register struct socket *so; 1507 struct file **extra_ref, **fpp; 1508 int nunref, i; 1509 int nfiles_snap; 1510 int nfiles_slack = 20; 1511 1512 UNP_LOCK_ASSERT(); 1513 1514 if (unp_gcing) { 1515 UNP_UNLOCK(); 1516 return; 1517 } 1518 unp_gcing = 1; 1519 unp_defer = 0; 1520 UNP_UNLOCK(); 1521 /* 1522 * before going through all this, set all FDs to 1523 * be NOT defered and NOT externally accessible 1524 */ 1525 sx_slock(&filelist_lock); 1526 LIST_FOREACH(fp, &filehead, f_list) 1527 fp->f_gcflag &= ~(FMARK|FDEFER); 1528 do { 1529 LIST_FOREACH(fp, &filehead, f_list) { 1530 FILE_LOCK(fp); 1531 /* 1532 * If the file is not open, skip it 1533 */ 1534 if (fp->f_count == 0) { 1535 FILE_UNLOCK(fp); 1536 continue; 1537 } 1538 /* 1539 * If we already marked it as 'defer' in a 1540 * previous pass, then try process it this time 1541 * and un-mark it 1542 */ 1543 if (fp->f_gcflag & FDEFER) { 1544 fp->f_gcflag &= ~FDEFER; 1545 unp_defer--; 1546 } else { 1547 /* 1548 * if it's not defered, then check if it's 1549 * already marked.. if so skip it 1550 */ 1551 if (fp->f_gcflag & FMARK) { 1552 FILE_UNLOCK(fp); 1553 continue; 1554 } 1555 /* 1556 * If all references are from messages 1557 * in transit, then skip it. it's not 1558 * externally accessible. 1559 */ 1560 if (fp->f_count == fp->f_msgcount) { 1561 FILE_UNLOCK(fp); 1562 continue; 1563 } 1564 /* 1565 * If it got this far then it must be 1566 * externally accessible. 1567 */ 1568 fp->f_gcflag |= FMARK; 1569 } 1570 /* 1571 * either it was defered, or it is externally 1572 * accessible and not already marked so. 1573 * Now check if it is possibly one of OUR sockets. 1574 */ 1575 if (fp->f_type != DTYPE_SOCKET || 1576 (so = fp->f_data) == NULL) { 1577 FILE_UNLOCK(fp); 1578 continue; 1579 } 1580 FILE_UNLOCK(fp); 1581 if (so->so_proto->pr_domain != &localdomain || 1582 (so->so_proto->pr_flags&PR_RIGHTS) == 0) 1583 continue; 1584 #ifdef notdef 1585 if (so->so_rcv.sb_flags & SB_LOCK) { 1586 /* 1587 * This is problematical; it's not clear 1588 * we need to wait for the sockbuf to be 1589 * unlocked (on a uniprocessor, at least), 1590 * and it's also not clear what to do 1591 * if sbwait returns an error due to receipt 1592 * of a signal. If sbwait does return 1593 * an error, we'll go into an infinite 1594 * loop. Delete all of this for now. 1595 */ 1596 (void) sbwait(&so->so_rcv); 1597 goto restart; 1598 } 1599 #endif 1600 /* 1601 * So, Ok, it's one of our sockets and it IS externally 1602 * accessible (or was defered). Now we look 1603 * to see if we hold any file descriptors in its 1604 * message buffers. Follow those links and mark them 1605 * as accessible too. 1606 */ 1607 SOCKBUF_LOCK(&so->so_rcv); 1608 unp_scan(so->so_rcv.sb_mb, unp_mark); 1609 SOCKBUF_UNLOCK(&so->so_rcv); 1610 } 1611 } while (unp_defer); 1612 sx_sunlock(&filelist_lock); 1613 /* 1614 * We grab an extra reference to each of the file table entries 1615 * that are not otherwise accessible and then free the rights 1616 * that are stored in messages on them. 1617 * 1618 * The bug in the orginal code is a little tricky, so I'll describe 1619 * what's wrong with it here. 1620 * 1621 * It is incorrect to simply unp_discard each entry for f_msgcount 1622 * times -- consider the case of sockets A and B that contain 1623 * references to each other. On a last close of some other socket, 1624 * we trigger a gc since the number of outstanding rights (unp_rights) 1625 * is non-zero. If during the sweep phase the gc code un_discards, 1626 * we end up doing a (full) closef on the descriptor. A closef on A 1627 * results in the following chain. Closef calls soo_close, which 1628 * calls soclose. Soclose calls first (through the switch 1629 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1630 * returns because the previous instance had set unp_gcing, and 1631 * we return all the way back to soclose, which marks the socket 1632 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1633 * to free up the rights that are queued in messages on the socket A, 1634 * i.e., the reference on B. The sorflush calls via the dom_dispose 1635 * switch unp_dispose, which unp_scans with unp_discard. This second 1636 * instance of unp_discard just calls closef on B. 1637 * 1638 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1639 * which results in another closef on A. Unfortunately, A is already 1640 * being closed, and the descriptor has already been marked with 1641 * SS_NOFDREF, and soclose panics at this point. 1642 * 1643 * Here, we first take an extra reference to each inaccessible 1644 * descriptor. Then, we call sorflush ourself, since we know 1645 * it is a Unix domain socket anyhow. After we destroy all the 1646 * rights carried in messages, we do a last closef to get rid 1647 * of our extra reference. This is the last close, and the 1648 * unp_detach etc will shut down the socket. 1649 * 1650 * 91/09/19, bsy@cs.cmu.edu 1651 */ 1652 again: 1653 nfiles_snap = nfiles + nfiles_slack; /* some slack */ 1654 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 1655 M_WAITOK); 1656 sx_slock(&filelist_lock); 1657 if (nfiles_snap < nfiles) { 1658 sx_sunlock(&filelist_lock); 1659 free(extra_ref, M_TEMP); 1660 nfiles_slack += 20; 1661 goto again; 1662 } 1663 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 1664 fp != NULL; fp = nextfp) { 1665 nextfp = LIST_NEXT(fp, f_list); 1666 FILE_LOCK(fp); 1667 /* 1668 * If it's not open, skip it 1669 */ 1670 if (fp->f_count == 0) { 1671 FILE_UNLOCK(fp); 1672 continue; 1673 } 1674 /* 1675 * If all refs are from msgs, and it's not marked accessible 1676 * then it must be referenced from some unreachable cycle 1677 * of (shut-down) FDs, so include it in our 1678 * list of FDs to remove 1679 */ 1680 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 1681 *fpp++ = fp; 1682 nunref++; 1683 fp->f_count++; 1684 } 1685 FILE_UNLOCK(fp); 1686 } 1687 sx_sunlock(&filelist_lock); 1688 /* 1689 * for each FD on our hit list, do the following two things 1690 */ 1691 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1692 struct file *tfp = *fpp; 1693 FILE_LOCK(tfp); 1694 if (tfp->f_type == DTYPE_SOCKET && 1695 tfp->f_data != NULL) { 1696 FILE_UNLOCK(tfp); 1697 sorflush(tfp->f_data); 1698 } else { 1699 FILE_UNLOCK(tfp); 1700 } 1701 } 1702 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) 1703 closef(*fpp, (struct thread *) NULL); 1704 free(extra_ref, M_TEMP); 1705 unp_gcing = 0; 1706 1707 UNP_UNLOCK_ASSERT(); 1708 } 1709 1710 void 1711 unp_dispose(m) 1712 struct mbuf *m; 1713 { 1714 1715 if (m) 1716 unp_scan(m, unp_discard); 1717 } 1718 1719 static int 1720 unp_listen(unp, td) 1721 struct unpcb *unp; 1722 struct thread *td; 1723 { 1724 UNP_LOCK_ASSERT(); 1725 1726 /* 1727 * XXXRW: Why populate the local peer cred with our own credential? 1728 */ 1729 cru2x(td->td_ucred, &unp->unp_peercred); 1730 unp->unp_flags |= UNP_HAVEPCCACHED; 1731 return (0); 1732 } 1733 1734 static void 1735 unp_scan(m0, op) 1736 register struct mbuf *m0; 1737 void (*op)(struct file *); 1738 { 1739 struct mbuf *m; 1740 struct file **rp; 1741 struct cmsghdr *cm; 1742 void *data; 1743 int i; 1744 socklen_t clen, datalen; 1745 int qfds; 1746 1747 while (m0 != NULL) { 1748 for (m = m0; m; m = m->m_next) { 1749 if (m->m_type != MT_CONTROL) 1750 continue; 1751 1752 cm = mtod(m, struct cmsghdr *); 1753 clen = m->m_len; 1754 1755 while (cm != NULL) { 1756 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 1757 break; 1758 1759 data = CMSG_DATA(cm); 1760 datalen = (caddr_t)cm + cm->cmsg_len 1761 - (caddr_t)data; 1762 1763 if (cm->cmsg_level == SOL_SOCKET && 1764 cm->cmsg_type == SCM_RIGHTS) { 1765 qfds = datalen / sizeof (struct file *); 1766 rp = data; 1767 for (i = 0; i < qfds; i++) 1768 (*op)(*rp++); 1769 } 1770 1771 if (CMSG_SPACE(datalen) < clen) { 1772 clen -= CMSG_SPACE(datalen); 1773 cm = (struct cmsghdr *) 1774 ((caddr_t)cm + CMSG_SPACE(datalen)); 1775 } else { 1776 clen = 0; 1777 cm = NULL; 1778 } 1779 } 1780 } 1781 m0 = m0->m_act; 1782 } 1783 } 1784 1785 static void 1786 unp_mark(fp) 1787 struct file *fp; 1788 { 1789 if (fp->f_gcflag & FMARK) 1790 return; 1791 unp_defer++; 1792 fp->f_gcflag |= (FMARK|FDEFER); 1793 } 1794 1795 static void 1796 unp_discard(fp) 1797 struct file *fp; 1798 { 1799 FILE_LOCK(fp); 1800 fp->f_msgcount--; 1801 unp_rights--; 1802 FILE_UNLOCK(fp); 1803 (void) closef(fp, (struct thread *)NULL); 1804 } 1805