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 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(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 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 456 error = EPIPE; 457 break; 458 } 459 if (unp->unp_conn == NULL) 460 panic("uipc_send connected but no connection?"); 461 so2 = unp->unp_conn->unp_socket; 462 SOCKBUF_LOCK(&so2->so_rcv); 463 /* 464 * Send to paired receive port, and then reduce 465 * send buffer hiwater marks to maintain backpressure. 466 * Wake up readers. 467 */ 468 if (control != NULL) { 469 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 470 control = NULL; 471 } else { 472 sbappend_locked(&so2->so_rcv, m); 473 } 474 so->so_snd.sb_mbmax -= 475 so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt; 476 unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt; 477 newhiwat = so->so_snd.sb_hiwat - 478 (so2->so_rcv.sb_cc - unp->unp_conn->unp_cc); 479 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 480 newhiwat, RLIM_INFINITY); 481 unp->unp_conn->unp_cc = so2->so_rcv.sb_cc; 482 sorwakeup_locked(so2); 483 m = NULL; 484 break; 485 486 default: 487 panic("uipc_send unknown socktype"); 488 } 489 490 /* 491 * SEND_EOF is equivalent to a SEND followed by 492 * a SHUTDOWN. 493 */ 494 if (flags & PRUS_EOF) { 495 socantsendmore(so); 496 unp_shutdown(unp); 497 } 498 UNP_UNLOCK(); 499 500 dispose_release: 501 if (control != NULL && error != 0) 502 unp_dispose(control); 503 504 release: 505 if (control != NULL) 506 m_freem(control); 507 if (m != NULL) 508 m_freem(m); 509 return (error); 510 } 511 512 static int 513 uipc_sense(struct socket *so, struct stat *sb) 514 { 515 struct unpcb *unp; 516 struct socket *so2; 517 518 UNP_LOCK(); 519 unp = sotounpcb(so); 520 if (unp == NULL) { 521 UNP_UNLOCK(); 522 return (EINVAL); 523 } 524 sb->st_blksize = so->so_snd.sb_hiwat; 525 if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { 526 so2 = unp->unp_conn->unp_socket; 527 sb->st_blksize += so2->so_rcv.sb_cc; 528 } 529 sb->st_dev = NODEV; 530 if (unp->unp_ino == 0) 531 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 532 sb->st_ino = unp->unp_ino; 533 UNP_UNLOCK(); 534 return (0); 535 } 536 537 static int 538 uipc_shutdown(struct socket *so) 539 { 540 struct unpcb *unp; 541 542 UNP_LOCK(); 543 unp = sotounpcb(so); 544 if (unp == NULL) { 545 UNP_UNLOCK(); 546 return (EINVAL); 547 } 548 socantsendmore(so); 549 unp_shutdown(unp); 550 UNP_UNLOCK(); 551 return (0); 552 } 553 554 static int 555 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 556 { 557 struct unpcb *unp; 558 const struct sockaddr *sa; 559 560 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 561 UNP_LOCK(); 562 unp = sotounpcb(so); 563 if (unp == NULL) { 564 UNP_UNLOCK(); 565 free(*nam, M_SONAME); 566 *nam = NULL; 567 return (EINVAL); 568 } 569 if (unp->unp_addr != NULL) 570 sa = (struct sockaddr *) unp->unp_addr; 571 else 572 sa = &sun_noname; 573 bcopy(sa, *nam, sa->sa_len); 574 UNP_UNLOCK(); 575 return (0); 576 } 577 578 struct pr_usrreqs uipc_usrreqs = { 579 uipc_abort, uipc_accept, uipc_attach, uipc_bind, uipc_connect, 580 uipc_connect2, pru_control_notsupp, uipc_detach, uipc_disconnect, 581 uipc_listen, uipc_peeraddr, uipc_rcvd, pru_rcvoob_notsupp, 582 uipc_send, uipc_sense, uipc_shutdown, uipc_sockaddr, 583 sosend, soreceive, sopoll, pru_sosetlabel_null 584 }; 585 586 int 587 uipc_ctloutput(so, sopt) 588 struct socket *so; 589 struct sockopt *sopt; 590 { 591 struct unpcb *unp; 592 struct xucred xu; 593 int error; 594 595 switch (sopt->sopt_dir) { 596 case SOPT_GET: 597 switch (sopt->sopt_name) { 598 case LOCAL_PEERCRED: 599 error = 0; 600 UNP_LOCK(); 601 unp = sotounpcb(so); 602 if (unp == NULL) { 603 UNP_UNLOCK(); 604 error = EINVAL; 605 break; 606 } 607 if (unp->unp_flags & UNP_HAVEPC) 608 xu = unp->unp_peercred; 609 else { 610 if (so->so_type == SOCK_STREAM) 611 error = ENOTCONN; 612 else 613 error = EINVAL; 614 } 615 UNP_UNLOCK(); 616 if (error == 0) 617 error = sooptcopyout(sopt, &xu, sizeof(xu)); 618 break; 619 default: 620 error = EOPNOTSUPP; 621 break; 622 } 623 break; 624 case SOPT_SET: 625 default: 626 error = EOPNOTSUPP; 627 break; 628 } 629 return (error); 630 } 631 632 /* 633 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 634 * for stream sockets, although the total for sender and receiver is 635 * actually only PIPSIZ. 636 * Datagram sockets really use the sendspace as the maximum datagram size, 637 * and don't really want to reserve the sendspace. Their recvspace should 638 * be large enough for at least one max-size datagram plus address. 639 */ 640 #ifndef PIPSIZ 641 #define PIPSIZ 8192 642 #endif 643 static u_long unpst_sendspace = PIPSIZ; 644 static u_long unpst_recvspace = PIPSIZ; 645 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 646 static u_long unpdg_recvspace = 4*1024; 647 648 static int unp_rights; /* file descriptors in flight */ 649 650 SYSCTL_DECL(_net_local_stream); 651 SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 652 &unpst_sendspace, 0, ""); 653 SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 654 &unpst_recvspace, 0, ""); 655 SYSCTL_DECL(_net_local_dgram); 656 SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 657 &unpdg_sendspace, 0, ""); 658 SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 659 &unpdg_recvspace, 0, ""); 660 SYSCTL_DECL(_net_local); 661 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 662 663 static int 664 unp_attach(so) 665 struct socket *so; 666 { 667 register 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); 688 if (unp == NULL) 689 return (ENOBUFS); 690 bzero(unp, sizeof *unp); 691 LIST_INIT(&unp->unp_refs); 692 unp->unp_socket = so; 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 so->so_pcb = unp; 700 UNP_UNLOCK(); 701 702 return (0); 703 } 704 705 static void 706 unp_detach(unp) 707 register struct unpcb *unp; 708 { 709 struct vnode *vp; 710 711 UNP_LOCK_ASSERT(); 712 713 LIST_REMOVE(unp, unp_link); 714 unp->unp_gencnt = ++unp_gencnt; 715 --unp_count; 716 if ((vp = unp->unp_vnode) != NULL) { 717 /* 718 * XXXRW: should v_socket be frobbed only while holding 719 * Giant? 720 */ 721 unp->unp_vnode->v_socket = NULL; 722 unp->unp_vnode = NULL; 723 } 724 if (unp->unp_conn != NULL) 725 unp_disconnect(unp); 726 while (!LIST_EMPTY(&unp->unp_refs)) { 727 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 728 unp_drop(ref, ECONNRESET); 729 } 730 soisdisconnected(unp->unp_socket); 731 unp->unp_socket->so_pcb = NULL; 732 if (unp_rights) { 733 /* 734 * Normally the receive buffer is flushed later, 735 * in sofree, but if our receive buffer holds references 736 * to descriptors that are now garbage, we will dispose 737 * of those descriptor references after the garbage collector 738 * gets them (resulting in a "panic: closef: count < 0"). 739 */ 740 sorflush(unp->unp_socket); 741 unp_gc(); /* Will unlock UNP. */ 742 } else 743 UNP_UNLOCK(); 744 UNP_UNLOCK_ASSERT(); 745 if (unp->unp_addr != NULL) 746 FREE(unp->unp_addr, M_SONAME); 747 uma_zfree(unp_zone, unp); 748 if (vp) { 749 mtx_lock(&Giant); 750 vrele(vp); 751 mtx_unlock(&Giant); 752 } 753 } 754 755 static int 756 unp_bind(unp, nam, td) 757 struct unpcb *unp; 758 struct sockaddr *nam; 759 struct thread *td; 760 { 761 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 762 struct vnode *vp; 763 struct mount *mp; 764 struct vattr vattr; 765 int error, namelen; 766 struct nameidata nd; 767 char *buf; 768 769 UNP_LOCK_ASSERT(); 770 771 /* 772 * XXXRW: This test-and-set of unp_vnode is non-atomic; the 773 * unlocked read here is fine, but the value of unp_vnode needs 774 * to be tested again after we do all the lookups to see if the 775 * pcb is still unbound? 776 */ 777 if (unp->unp_vnode != NULL) 778 return (EINVAL); 779 780 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 781 if (namelen <= 0) 782 return (EINVAL); 783 784 UNP_UNLOCK(); 785 786 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 787 strlcpy(buf, soun->sun_path, namelen + 1); 788 789 mtx_lock(&Giant); 790 restart: 791 mtx_assert(&Giant, MA_OWNED); 792 NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, 793 buf, td); 794 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 795 error = namei(&nd); 796 if (error) 797 goto done; 798 vp = nd.ni_vp; 799 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 800 NDFREE(&nd, NDF_ONLY_PNBUF); 801 if (nd.ni_dvp == vp) 802 vrele(nd.ni_dvp); 803 else 804 vput(nd.ni_dvp); 805 if (vp != NULL) { 806 vrele(vp); 807 error = EADDRINUSE; 808 goto done; 809 } 810 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 811 if (error) 812 goto done; 813 goto restart; 814 } 815 VATTR_NULL(&vattr); 816 vattr.va_type = VSOCK; 817 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 818 #ifdef MAC 819 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 820 &vattr); 821 #endif 822 if (error == 0) { 823 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 824 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 825 } 826 NDFREE(&nd, NDF_ONLY_PNBUF); 827 vput(nd.ni_dvp); 828 if (error) 829 goto done; 830 vp = nd.ni_vp; 831 ASSERT_VOP_LOCKED(vp, "unp_bind"); 832 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 833 UNP_LOCK(); 834 vp->v_socket = unp->unp_socket; 835 unp->unp_vnode = vp; 836 unp->unp_addr = soun; 837 UNP_UNLOCK(); 838 VOP_UNLOCK(vp, 0, td); 839 vn_finished_write(mp); 840 done: 841 mtx_unlock(&Giant); 842 free(buf, M_TEMP); 843 UNP_LOCK(); 844 return (error); 845 } 846 847 static int 848 unp_connect(so, nam, td) 849 struct socket *so; 850 struct sockaddr *nam; 851 struct thread *td; 852 { 853 register struct sockaddr_un *soun = (struct sockaddr_un *)nam; 854 register struct vnode *vp; 855 register struct socket *so2, *so3; 856 struct unpcb *unp, *unp2, *unp3; 857 int error, len; 858 struct nameidata nd; 859 char buf[SOCK_MAXADDRLEN]; 860 struct sockaddr *sa; 861 862 UNP_LOCK_ASSERT(); 863 unp = sotounpcb(so); 864 865 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 866 if (len <= 0) 867 return (EINVAL); 868 strlcpy(buf, soun->sun_path, len + 1); 869 UNP_UNLOCK(); 870 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 871 mtx_lock(&Giant); 872 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); 873 error = namei(&nd); 874 if (error) 875 vp = NULL; 876 else 877 vp = nd.ni_vp; 878 ASSERT_VOP_LOCKED(vp, "unp_connect"); 879 NDFREE(&nd, NDF_ONLY_PNBUF); 880 if (error) 881 goto bad; 882 883 if (vp->v_type != VSOCK) { 884 error = ENOTSOCK; 885 goto bad; 886 } 887 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 888 if (error) 889 goto bad; 890 mtx_unlock(&Giant); 891 UNP_LOCK(); 892 unp = sotounpcb(so); 893 if (unp == NULL) { 894 /* 895 * XXXRW: Temporary debugging printf. 896 */ 897 printf("unp_connect(): lost race to another thread\n"); 898 error = EINVAL; 899 goto bad2; 900 } 901 so2 = vp->v_socket; 902 if (so2 == NULL) { 903 error = ECONNREFUSED; 904 goto bad2; 905 } 906 if (so->so_type != so2->so_type) { 907 error = EPROTOTYPE; 908 goto bad2; 909 } 910 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 911 if (so2->so_options & SO_ACCEPTCONN) { 912 /* 913 * NB: drop locks here so unp_attach is entered 914 * w/o locks; this avoids a recursive lock 915 * of the head and holding sleep locks across 916 * a (potentially) blocking malloc. 917 */ 918 UNP_UNLOCK(); 919 so3 = sonewconn(so2, 0); 920 UNP_LOCK(); 921 } else 922 so3 = NULL; 923 if (so3 == NULL) { 924 error = ECONNREFUSED; 925 goto bad2; 926 } 927 unp = sotounpcb(so); 928 unp2 = sotounpcb(so2); 929 unp3 = sotounpcb(so3); 930 if (unp2->unp_addr != NULL) { 931 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 932 unp3->unp_addr = (struct sockaddr_un *) sa; 933 sa = NULL; 934 } 935 /* 936 * unp_peercred management: 937 * 938 * The connecter's (client's) credentials are copied 939 * from its process structure at the time of connect() 940 * (which is now). 941 */ 942 cru2x(td->td_ucred, &unp3->unp_peercred); 943 unp3->unp_flags |= UNP_HAVEPC; 944 /* 945 * The receiver's (server's) credentials are copied 946 * from the unp_peercred member of socket on which the 947 * former called listen(); unp_listen() cached that 948 * process's credentials at that time so we can use 949 * them now. 950 */ 951 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 952 ("unp_connect: listener without cached peercred")); 953 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 954 sizeof(unp->unp_peercred)); 955 unp->unp_flags |= UNP_HAVEPC; 956 #ifdef MAC 957 SOCK_LOCK(so); 958 mac_set_socket_peer_from_socket(so, so3); 959 mac_set_socket_peer_from_socket(so3, so); 960 SOCK_UNLOCK(so); 961 #endif 962 963 so2 = so3; 964 } 965 error = unp_connect2(so, so2); 966 bad2: 967 UNP_UNLOCK(); 968 mtx_lock(&Giant); 969 bad: 970 mtx_assert(&Giant, MA_OWNED); 971 if (vp != NULL) 972 vput(vp); 973 mtx_unlock(&Giant); 974 free(sa, M_SONAME); 975 UNP_LOCK(); 976 return (error); 977 } 978 979 static int 980 unp_connect2(so, so2) 981 register struct socket *so; 982 register struct socket *so2; 983 { 984 register struct unpcb *unp = sotounpcb(so); 985 register struct unpcb *unp2; 986 987 UNP_LOCK_ASSERT(); 988 989 if (so2->so_type != so->so_type) 990 return (EPROTOTYPE); 991 unp2 = sotounpcb(so2); 992 unp->unp_conn = unp2; 993 switch (so->so_type) { 994 995 case SOCK_DGRAM: 996 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 997 soisconnected(so); 998 break; 999 1000 case SOCK_STREAM: 1001 unp2->unp_conn = unp; 1002 soisconnected(so); 1003 soisconnected(so2); 1004 break; 1005 1006 default: 1007 panic("unp_connect2"); 1008 } 1009 return (0); 1010 } 1011 1012 static void 1013 unp_disconnect(unp) 1014 struct unpcb *unp; 1015 { 1016 register struct unpcb *unp2 = unp->unp_conn; 1017 struct socket *so; 1018 1019 UNP_LOCK_ASSERT(); 1020 1021 if (unp2 == NULL) 1022 return; 1023 unp->unp_conn = NULL; 1024 switch (unp->unp_socket->so_type) { 1025 1026 case SOCK_DGRAM: 1027 LIST_REMOVE(unp, unp_reflink); 1028 so = unp->unp_socket; 1029 SOCK_LOCK(so); 1030 so->so_state &= ~SS_ISCONNECTED; 1031 SOCK_UNLOCK(so); 1032 break; 1033 1034 case SOCK_STREAM: 1035 soisdisconnected(unp->unp_socket); 1036 unp2->unp_conn = NULL; 1037 soisdisconnected(unp2->unp_socket); 1038 break; 1039 } 1040 } 1041 1042 #ifdef notdef 1043 void 1044 unp_abort(unp) 1045 struct unpcb *unp; 1046 { 1047 1048 unp_detach(unp); 1049 UNP_UNLOCK_ASSERT(); 1050 } 1051 #endif 1052 1053 /* 1054 * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed 1055 * by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers 1056 * are safe to reference. It first scans the list of struct unpcb's to 1057 * generate a pointer list, then it rescans its list one entry at a time to 1058 * externalize and copyout. It checks the generation number to see if a 1059 * struct unpcb has been reused, and will skip it if so. 1060 */ 1061 static int 1062 unp_pcblist(SYSCTL_HANDLER_ARGS) 1063 { 1064 int error, i, n; 1065 struct unpcb *unp, **unp_list; 1066 unp_gen_t gencnt; 1067 struct xunpgen *xug; 1068 struct unp_head *head; 1069 struct xunpcb *xu; 1070 1071 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1072 1073 /* 1074 * The process of preparing the PCB list is too time-consuming and 1075 * resource-intensive to repeat twice on every request. 1076 */ 1077 if (req->oldptr == NULL) { 1078 n = unp_count; 1079 req->oldidx = 2 * (sizeof *xug) 1080 + (n + n/8) * sizeof(struct xunpcb); 1081 return (0); 1082 } 1083 1084 if (req->newptr != NULL) 1085 return (EPERM); 1086 1087 /* 1088 * OK, now we're committed to doing something. 1089 */ 1090 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1091 UNP_LOCK(); 1092 gencnt = unp_gencnt; 1093 n = unp_count; 1094 UNP_UNLOCK(); 1095 1096 xug->xug_len = sizeof *xug; 1097 xug->xug_count = n; 1098 xug->xug_gen = gencnt; 1099 xug->xug_sogen = so_gencnt; 1100 error = SYSCTL_OUT(req, xug, sizeof *xug); 1101 if (error) { 1102 free(xug, M_TEMP); 1103 return (error); 1104 } 1105 1106 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1107 1108 UNP_LOCK(); 1109 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1110 unp = LIST_NEXT(unp, unp_link)) { 1111 if (unp->unp_gencnt <= gencnt) { 1112 if (cr_cansee(req->td->td_ucred, 1113 unp->unp_socket->so_cred)) 1114 continue; 1115 unp_list[i++] = unp; 1116 } 1117 } 1118 UNP_UNLOCK(); 1119 n = i; /* in case we lost some during malloc */ 1120 1121 error = 0; 1122 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK); 1123 for (i = 0; i < n; i++) { 1124 unp = unp_list[i]; 1125 if (unp->unp_gencnt <= gencnt) { 1126 xu->xu_len = sizeof *xu; 1127 xu->xu_unpp = unp; 1128 /* 1129 * XXX - need more locking here to protect against 1130 * connect/disconnect races for SMP. 1131 */ 1132 if (unp->unp_addr != NULL) 1133 bcopy(unp->unp_addr, &xu->xu_addr, 1134 unp->unp_addr->sun_len); 1135 if (unp->unp_conn != NULL && 1136 unp->unp_conn->unp_addr != NULL) 1137 bcopy(unp->unp_conn->unp_addr, 1138 &xu->xu_caddr, 1139 unp->unp_conn->unp_addr->sun_len); 1140 bcopy(unp, &xu->xu_unp, sizeof *unp); 1141 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1142 error = SYSCTL_OUT(req, xu, sizeof *xu); 1143 } 1144 } 1145 free(xu, M_TEMP); 1146 if (!error) { 1147 /* 1148 * Give the user an updated idea of our state. 1149 * If the generation differs from what we told 1150 * her before, she knows that something happened 1151 * while we were processing this request, and it 1152 * might be necessary to retry. 1153 */ 1154 xug->xug_gen = unp_gencnt; 1155 xug->xug_sogen = so_gencnt; 1156 xug->xug_count = unp_count; 1157 error = SYSCTL_OUT(req, xug, sizeof *xug); 1158 } 1159 free(unp_list, M_TEMP); 1160 free(xug, M_TEMP); 1161 return (error); 1162 } 1163 1164 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1165 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1166 "List of active local datagram sockets"); 1167 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1168 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1169 "List of active local stream sockets"); 1170 1171 static void 1172 unp_shutdown(unp) 1173 struct unpcb *unp; 1174 { 1175 struct socket *so; 1176 1177 UNP_LOCK_ASSERT(); 1178 1179 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1180 (so = unp->unp_conn->unp_socket)) 1181 socantrcvmore(so); 1182 } 1183 1184 static void 1185 unp_drop(unp, errno) 1186 struct unpcb *unp; 1187 int errno; 1188 { 1189 struct socket *so = unp->unp_socket; 1190 1191 UNP_LOCK_ASSERT(); 1192 1193 so->so_error = errno; 1194 unp_disconnect(unp); 1195 } 1196 1197 #ifdef notdef 1198 void 1199 unp_drain() 1200 { 1201 1202 } 1203 #endif 1204 1205 static void 1206 unp_freerights(rp, fdcount) 1207 struct file **rp; 1208 int fdcount; 1209 { 1210 int i; 1211 struct file *fp; 1212 1213 for (i = 0; i < fdcount; i++) { 1214 fp = *rp; 1215 /* 1216 * zero the pointer before calling 1217 * unp_discard since it may end up 1218 * in unp_gc().. 1219 */ 1220 *rp++ = 0; 1221 unp_discard(fp); 1222 } 1223 } 1224 1225 int 1226 unp_externalize(control, controlp) 1227 struct mbuf *control, **controlp; 1228 { 1229 struct thread *td = curthread; /* XXX */ 1230 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1231 int i; 1232 int *fdp; 1233 struct file **rp; 1234 struct file *fp; 1235 void *data; 1236 socklen_t clen = control->m_len, datalen; 1237 int error, newfds; 1238 int f; 1239 u_int newlen; 1240 1241 UNP_UNLOCK_ASSERT(); 1242 1243 error = 0; 1244 if (controlp != NULL) /* controlp == NULL => free control messages */ 1245 *controlp = NULL; 1246 1247 while (cm != NULL) { 1248 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1249 error = EINVAL; 1250 break; 1251 } 1252 1253 data = CMSG_DATA(cm); 1254 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1255 1256 if (cm->cmsg_level == SOL_SOCKET 1257 && cm->cmsg_type == SCM_RIGHTS) { 1258 newfds = datalen / sizeof(struct file *); 1259 rp = data; 1260 1261 /* If we're not outputting the descriptors free them. */ 1262 if (error || controlp == NULL) { 1263 unp_freerights(rp, newfds); 1264 goto next; 1265 } 1266 FILEDESC_LOCK(td->td_proc->p_fd); 1267 /* if the new FD's will not fit free them. */ 1268 if (!fdavail(td, newfds)) { 1269 FILEDESC_UNLOCK(td->td_proc->p_fd); 1270 error = EMSGSIZE; 1271 unp_freerights(rp, newfds); 1272 goto next; 1273 } 1274 /* 1275 * now change each pointer to an fd in the global 1276 * table to an integer that is the index to the 1277 * local fd table entry that we set up to point 1278 * to the global one we are transferring. 1279 */ 1280 newlen = newfds * sizeof(int); 1281 *controlp = sbcreatecontrol(NULL, newlen, 1282 SCM_RIGHTS, SOL_SOCKET); 1283 if (*controlp == NULL) { 1284 FILEDESC_UNLOCK(td->td_proc->p_fd); 1285 error = E2BIG; 1286 unp_freerights(rp, newfds); 1287 goto next; 1288 } 1289 1290 fdp = (int *) 1291 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1292 for (i = 0; i < newfds; i++) { 1293 if (fdalloc(td, 0, &f)) 1294 panic("unp_externalize fdalloc failed"); 1295 fp = *rp++; 1296 td->td_proc->p_fd->fd_ofiles[f] = fp; 1297 FILE_LOCK(fp); 1298 fp->f_msgcount--; 1299 FILE_UNLOCK(fp); 1300 unp_rights--; 1301 *fdp++ = f; 1302 } 1303 FILEDESC_UNLOCK(td->td_proc->p_fd); 1304 } else { /* We can just copy anything else across */ 1305 if (error || controlp == NULL) 1306 goto next; 1307 *controlp = sbcreatecontrol(NULL, datalen, 1308 cm->cmsg_type, cm->cmsg_level); 1309 if (*controlp == NULL) { 1310 error = ENOBUFS; 1311 goto next; 1312 } 1313 bcopy(data, 1314 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1315 datalen); 1316 } 1317 1318 controlp = &(*controlp)->m_next; 1319 1320 next: 1321 if (CMSG_SPACE(datalen) < clen) { 1322 clen -= CMSG_SPACE(datalen); 1323 cm = (struct cmsghdr *) 1324 ((caddr_t)cm + CMSG_SPACE(datalen)); 1325 } else { 1326 clen = 0; 1327 cm = NULL; 1328 } 1329 } 1330 1331 m_freem(control); 1332 1333 return (error); 1334 } 1335 1336 void 1337 unp_init(void) 1338 { 1339 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1340 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 1341 if (unp_zone == NULL) 1342 panic("unp_init"); 1343 uma_zone_set_max(unp_zone, nmbclusters); 1344 LIST_INIT(&unp_dhead); 1345 LIST_INIT(&unp_shead); 1346 1347 UNP_LOCK_INIT(); 1348 } 1349 1350 static int 1351 unp_internalize(controlp, td) 1352 struct mbuf **controlp; 1353 struct thread *td; 1354 { 1355 struct mbuf *control = *controlp; 1356 struct proc *p = td->td_proc; 1357 struct filedesc *fdescp = p->p_fd; 1358 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1359 struct cmsgcred *cmcred; 1360 struct file **rp; 1361 struct file *fp; 1362 struct timeval *tv; 1363 int i, fd, *fdp; 1364 void *data; 1365 socklen_t clen = control->m_len, datalen; 1366 int error, oldfds; 1367 u_int newlen; 1368 1369 UNP_UNLOCK_ASSERT(); 1370 1371 error = 0; 1372 *controlp = NULL; 1373 1374 while (cm != NULL) { 1375 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1376 || cm->cmsg_len > clen) { 1377 error = EINVAL; 1378 goto out; 1379 } 1380 1381 data = CMSG_DATA(cm); 1382 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1383 1384 switch (cm->cmsg_type) { 1385 /* 1386 * Fill in credential information. 1387 */ 1388 case SCM_CREDS: 1389 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1390 SCM_CREDS, SOL_SOCKET); 1391 if (*controlp == NULL) { 1392 error = ENOBUFS; 1393 goto out; 1394 } 1395 1396 cmcred = (struct cmsgcred *) 1397 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1398 cmcred->cmcred_pid = p->p_pid; 1399 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1400 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1401 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1402 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1403 CMGROUP_MAX); 1404 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1405 cmcred->cmcred_groups[i] = 1406 td->td_ucred->cr_groups[i]; 1407 break; 1408 1409 case SCM_RIGHTS: 1410 oldfds = datalen / sizeof (int); 1411 /* 1412 * check that all the FDs passed in refer to legal files 1413 * If not, reject the entire operation. 1414 */ 1415 fdp = data; 1416 FILEDESC_LOCK(fdescp); 1417 for (i = 0; i < oldfds; i++) { 1418 fd = *fdp++; 1419 if ((unsigned)fd >= fdescp->fd_nfiles || 1420 fdescp->fd_ofiles[fd] == NULL) { 1421 FILEDESC_UNLOCK(fdescp); 1422 error = EBADF; 1423 goto out; 1424 } 1425 fp = fdescp->fd_ofiles[fd]; 1426 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1427 FILEDESC_UNLOCK(fdescp); 1428 error = EOPNOTSUPP; 1429 goto out; 1430 } 1431 1432 } 1433 /* 1434 * Now replace the integer FDs with pointers to 1435 * the associated global file table entry.. 1436 */ 1437 newlen = oldfds * sizeof(struct file *); 1438 *controlp = sbcreatecontrol(NULL, newlen, 1439 SCM_RIGHTS, SOL_SOCKET); 1440 if (*controlp == NULL) { 1441 FILEDESC_UNLOCK(fdescp); 1442 error = E2BIG; 1443 goto out; 1444 } 1445 1446 fdp = data; 1447 rp = (struct file **) 1448 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1449 for (i = 0; i < oldfds; i++) { 1450 fp = fdescp->fd_ofiles[*fdp++]; 1451 *rp++ = fp; 1452 FILE_LOCK(fp); 1453 fp->f_count++; 1454 fp->f_msgcount++; 1455 FILE_UNLOCK(fp); 1456 unp_rights++; 1457 } 1458 FILEDESC_UNLOCK(fdescp); 1459 break; 1460 1461 case SCM_TIMESTAMP: 1462 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1463 SCM_TIMESTAMP, SOL_SOCKET); 1464 if (*controlp == NULL) { 1465 error = ENOBUFS; 1466 goto out; 1467 } 1468 tv = (struct timeval *) 1469 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1470 microtime(tv); 1471 break; 1472 1473 default: 1474 error = EINVAL; 1475 goto out; 1476 } 1477 1478 controlp = &(*controlp)->m_next; 1479 1480 if (CMSG_SPACE(datalen) < clen) { 1481 clen -= CMSG_SPACE(datalen); 1482 cm = (struct cmsghdr *) 1483 ((caddr_t)cm + CMSG_SPACE(datalen)); 1484 } else { 1485 clen = 0; 1486 cm = NULL; 1487 } 1488 } 1489 1490 out: 1491 m_freem(control); 1492 1493 return (error); 1494 } 1495 1496 /* 1497 * unp_defer is thread-local during garbage collection, and does not require 1498 * explicit synchronization. unp_gcing prevents other threads from entering 1499 * garbage collection, and perhaps should be an sx lock instead. 1500 */ 1501 static int unp_defer, unp_gcing; 1502 1503 static void 1504 unp_gc() 1505 { 1506 register struct file *fp, *nextfp; 1507 register struct socket *so; 1508 struct file **extra_ref, **fpp; 1509 int nunref, i; 1510 int nfiles_snap; 1511 int nfiles_slack = 20; 1512 1513 UNP_LOCK_ASSERT(); 1514 1515 if (unp_gcing) { 1516 UNP_UNLOCK(); 1517 return; 1518 } 1519 unp_gcing = 1; 1520 unp_defer = 0; 1521 UNP_UNLOCK(); 1522 /* 1523 * before going through all this, set all FDs to 1524 * be NOT defered and NOT externally accessible 1525 */ 1526 sx_slock(&filelist_lock); 1527 LIST_FOREACH(fp, &filehead, f_list) 1528 fp->f_gcflag &= ~(FMARK|FDEFER); 1529 do { 1530 LIST_FOREACH(fp, &filehead, f_list) { 1531 FILE_LOCK(fp); 1532 /* 1533 * If the file is not open, skip it 1534 */ 1535 if (fp->f_count == 0) { 1536 FILE_UNLOCK(fp); 1537 continue; 1538 } 1539 /* 1540 * If we already marked it as 'defer' in a 1541 * previous pass, then try process it this time 1542 * and un-mark it 1543 */ 1544 if (fp->f_gcflag & FDEFER) { 1545 fp->f_gcflag &= ~FDEFER; 1546 unp_defer--; 1547 } else { 1548 /* 1549 * if it's not defered, then check if it's 1550 * already marked.. if so skip it 1551 */ 1552 if (fp->f_gcflag & FMARK) { 1553 FILE_UNLOCK(fp); 1554 continue; 1555 } 1556 /* 1557 * If all references are from messages 1558 * in transit, then skip it. it's not 1559 * externally accessible. 1560 */ 1561 if (fp->f_count == fp->f_msgcount) { 1562 FILE_UNLOCK(fp); 1563 continue; 1564 } 1565 /* 1566 * If it got this far then it must be 1567 * externally accessible. 1568 */ 1569 fp->f_gcflag |= FMARK; 1570 } 1571 /* 1572 * either it was defered, or it is externally 1573 * accessible and not already marked so. 1574 * Now check if it is possibly one of OUR sockets. 1575 */ 1576 if (fp->f_type != DTYPE_SOCKET || 1577 (so = fp->f_data) == NULL) { 1578 FILE_UNLOCK(fp); 1579 continue; 1580 } 1581 FILE_UNLOCK(fp); 1582 if (so->so_proto->pr_domain != &localdomain || 1583 (so->so_proto->pr_flags&PR_RIGHTS) == 0) 1584 continue; 1585 #ifdef notdef 1586 if (so->so_rcv.sb_flags & SB_LOCK) { 1587 /* 1588 * This is problematical; it's not clear 1589 * we need to wait for the sockbuf to be 1590 * unlocked (on a uniprocessor, at least), 1591 * and it's also not clear what to do 1592 * if sbwait returns an error due to receipt 1593 * of a signal. If sbwait does return 1594 * an error, we'll go into an infinite 1595 * loop. Delete all of this for now. 1596 */ 1597 (void) sbwait(&so->so_rcv); 1598 goto restart; 1599 } 1600 #endif 1601 /* 1602 * So, Ok, it's one of our sockets and it IS externally 1603 * accessible (or was defered). Now we look 1604 * to see if we hold any file descriptors in its 1605 * message buffers. Follow those links and mark them 1606 * as accessible too. 1607 */ 1608 SOCKBUF_LOCK(&so->so_rcv); 1609 unp_scan(so->so_rcv.sb_mb, unp_mark); 1610 SOCKBUF_UNLOCK(&so->so_rcv); 1611 } 1612 } while (unp_defer); 1613 sx_sunlock(&filelist_lock); 1614 /* 1615 * We grab an extra reference to each of the file table entries 1616 * that are not otherwise accessible and then free the rights 1617 * that are stored in messages on them. 1618 * 1619 * The bug in the orginal code is a little tricky, so I'll describe 1620 * what's wrong with it here. 1621 * 1622 * It is incorrect to simply unp_discard each entry for f_msgcount 1623 * times -- consider the case of sockets A and B that contain 1624 * references to each other. On a last close of some other socket, 1625 * we trigger a gc since the number of outstanding rights (unp_rights) 1626 * is non-zero. If during the sweep phase the gc code un_discards, 1627 * we end up doing a (full) closef on the descriptor. A closef on A 1628 * results in the following chain. Closef calls soo_close, which 1629 * calls soclose. Soclose calls first (through the switch 1630 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1631 * returns because the previous instance had set unp_gcing, and 1632 * we return all the way back to soclose, which marks the socket 1633 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1634 * to free up the rights that are queued in messages on the socket A, 1635 * i.e., the reference on B. The sorflush calls via the dom_dispose 1636 * switch unp_dispose, which unp_scans with unp_discard. This second 1637 * instance of unp_discard just calls closef on B. 1638 * 1639 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1640 * which results in another closef on A. Unfortunately, A is already 1641 * being closed, and the descriptor has already been marked with 1642 * SS_NOFDREF, and soclose panics at this point. 1643 * 1644 * Here, we first take an extra reference to each inaccessible 1645 * descriptor. Then, we call sorflush ourself, since we know 1646 * it is a Unix domain socket anyhow. After we destroy all the 1647 * rights carried in messages, we do a last closef to get rid 1648 * of our extra reference. This is the last close, and the 1649 * unp_detach etc will shut down the socket. 1650 * 1651 * 91/09/19, bsy@cs.cmu.edu 1652 */ 1653 again: 1654 nfiles_snap = nfiles + nfiles_slack; /* some slack */ 1655 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 1656 M_WAITOK); 1657 sx_slock(&filelist_lock); 1658 if (nfiles_snap < nfiles) { 1659 sx_sunlock(&filelist_lock); 1660 free(extra_ref, M_TEMP); 1661 nfiles_slack += 20; 1662 goto again; 1663 } 1664 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 1665 fp != NULL; fp = nextfp) { 1666 nextfp = LIST_NEXT(fp, f_list); 1667 FILE_LOCK(fp); 1668 /* 1669 * If it's not open, skip it 1670 */ 1671 if (fp->f_count == 0) { 1672 FILE_UNLOCK(fp); 1673 continue; 1674 } 1675 /* 1676 * If all refs are from msgs, and it's not marked accessible 1677 * then it must be referenced from some unreachable cycle 1678 * of (shut-down) FDs, so include it in our 1679 * list of FDs to remove 1680 */ 1681 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 1682 *fpp++ = fp; 1683 nunref++; 1684 fp->f_count++; 1685 } 1686 FILE_UNLOCK(fp); 1687 } 1688 sx_sunlock(&filelist_lock); 1689 /* 1690 * for each FD on our hit list, do the following two things 1691 */ 1692 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1693 struct file *tfp = *fpp; 1694 FILE_LOCK(tfp); 1695 if (tfp->f_type == DTYPE_SOCKET && 1696 tfp->f_data != NULL) { 1697 FILE_UNLOCK(tfp); 1698 sorflush(tfp->f_data); 1699 } else { 1700 FILE_UNLOCK(tfp); 1701 } 1702 } 1703 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) 1704 closef(*fpp, (struct thread *) NULL); 1705 free(extra_ref, M_TEMP); 1706 unp_gcing = 0; 1707 1708 UNP_UNLOCK_ASSERT(); 1709 } 1710 1711 void 1712 unp_dispose(m) 1713 struct mbuf *m; 1714 { 1715 1716 if (m) 1717 unp_scan(m, unp_discard); 1718 } 1719 1720 static int 1721 unp_listen(unp, td) 1722 struct unpcb *unp; 1723 struct thread *td; 1724 { 1725 UNP_LOCK_ASSERT(); 1726 1727 /* 1728 * XXXRW: Why populate the local peer cred with our own credential? 1729 */ 1730 cru2x(td->td_ucred, &unp->unp_peercred); 1731 unp->unp_flags |= UNP_HAVEPCCACHED; 1732 return (0); 1733 } 1734 1735 static void 1736 unp_scan(m0, op) 1737 register struct mbuf *m0; 1738 void (*op)(struct file *); 1739 { 1740 struct mbuf *m; 1741 struct file **rp; 1742 struct cmsghdr *cm; 1743 void *data; 1744 int i; 1745 socklen_t clen, datalen; 1746 int qfds; 1747 1748 while (m0 != NULL) { 1749 for (m = m0; m; m = m->m_next) { 1750 if (m->m_type != MT_CONTROL) 1751 continue; 1752 1753 cm = mtod(m, struct cmsghdr *); 1754 clen = m->m_len; 1755 1756 while (cm != NULL) { 1757 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 1758 break; 1759 1760 data = CMSG_DATA(cm); 1761 datalen = (caddr_t)cm + cm->cmsg_len 1762 - (caddr_t)data; 1763 1764 if (cm->cmsg_level == SOL_SOCKET && 1765 cm->cmsg_type == SCM_RIGHTS) { 1766 qfds = datalen / sizeof (struct file *); 1767 rp = data; 1768 for (i = 0; i < qfds; i++) 1769 (*op)(*rp++); 1770 } 1771 1772 if (CMSG_SPACE(datalen) < clen) { 1773 clen -= CMSG_SPACE(datalen); 1774 cm = (struct cmsghdr *) 1775 ((caddr_t)cm + CMSG_SPACE(datalen)); 1776 } else { 1777 clen = 0; 1778 cm = NULL; 1779 } 1780 } 1781 } 1782 m0 = m0->m_act; 1783 } 1784 } 1785 1786 static void 1787 unp_mark(fp) 1788 struct file *fp; 1789 { 1790 if (fp->f_gcflag & FMARK) 1791 return; 1792 unp_defer++; 1793 fp->f_gcflag |= (FMARK|FDEFER); 1794 } 1795 1796 static void 1797 unp_discard(fp) 1798 struct file *fp; 1799 { 1800 FILE_LOCK(fp); 1801 fp->f_msgcount--; 1802 unp_rights--; 1803 FILE_UNLOCK(fp); 1804 (void) closef(fp, (struct thread *)NULL); 1805 } 1806