uipc_usrreq.c revision 139211
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: head/sys/kern/uipc_usrreq.c 139211 2004-12-22 20:28:46Z alc $"); 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 67static uma_zone_t unp_zone; 68static unp_gen_t unp_gencnt; 69static u_int unp_count; 70 71static 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 */ 82static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; 83static 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 */ 105static 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 113static int unp_attach(struct socket *); 114static void unp_detach(struct unpcb *); 115static int unp_bind(struct unpcb *,struct sockaddr *, struct thread *); 116static int unp_connect(struct socket *,struct sockaddr *, struct thread *); 117static int unp_connect2(struct socket *so, struct socket *so2); 118static void unp_disconnect(struct unpcb *); 119static void unp_shutdown(struct unpcb *); 120static void unp_drop(struct unpcb *, int); 121static void unp_gc(void); 122static void unp_scan(struct mbuf *, void (*)(struct file *)); 123static void unp_mark(struct file *); 124static void unp_discard(struct file *); 125static void unp_freerights(struct file **, int); 126static int unp_internalize(struct mbuf **, struct thread *); 127static int unp_listen(struct unpcb *, struct thread *); 128 129static int 130uipc_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 149static int 150uipc_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 178static int 179uipc_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 188static int 189uipc_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 205static int 206uipc_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 224int 225uipc_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 243static int 244uipc_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 259static int 260uipc_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 275static int 276uipc_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 292static int 293uipc_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 322static int 323uipc_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 370static int 371uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 372 struct mbuf *control, struct thread *td) 373{ 374 int error = 0; 375 struct unpcb *unp; 376 struct socket *so2; 377 u_long newhiwat; 378 379 unp = sotounpcb(so); 380 if (unp == NULL) { 381 error = EINVAL; 382 goto release; 383 } 384 if (flags & PRUS_OOB) { 385 error = EOPNOTSUPP; 386 goto release; 387 } 388 389 if (control != NULL && (error = unp_internalize(&control, td))) 390 goto release; 391 392 UNP_LOCK(); 393 unp = sotounpcb(so); 394 if (unp == NULL) { 395 UNP_UNLOCK(); 396 error = EINVAL; 397 goto dispose_release; 398 } 399 400 switch (so->so_type) { 401 case SOCK_DGRAM: 402 { 403 const struct sockaddr *from; 404 405 if (nam != NULL) { 406 if (unp->unp_conn != NULL) { 407 error = EISCONN; 408 break; 409 } 410 error = unp_connect(so, nam, td); 411 if (error) 412 break; 413 } else { 414 if (unp->unp_conn == NULL) { 415 error = ENOTCONN; 416 break; 417 } 418 } 419 so2 = unp->unp_conn->unp_socket; 420 if (unp->unp_addr != NULL) 421 from = (struct sockaddr *)unp->unp_addr; 422 else 423 from = &sun_noname; 424 SOCKBUF_LOCK(&so2->so_rcv); 425 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 426 sorwakeup_locked(so2); 427 m = NULL; 428 control = NULL; 429 } else { 430 SOCKBUF_UNLOCK(&so2->so_rcv); 431 error = ENOBUFS; 432 } 433 if (nam != NULL) 434 unp_disconnect(unp); 435 break; 436 } 437 438 case SOCK_STREAM: 439 /* Connect if not connected yet. */ 440 /* 441 * Note: A better implementation would complain 442 * if not equal to the peer's address. 443 */ 444 if ((so->so_state & SS_ISCONNECTED) == 0) { 445 if (nam != NULL) { 446 error = unp_connect(so, nam, td); 447 if (error) 448 break; /* XXX */ 449 } else { 450 error = ENOTCONN; 451 break; 452 } 453 } 454 455 SOCKBUF_LOCK(&so->so_snd); 456 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 457 SOCKBUF_UNLOCK(&so->so_snd); 458 error = EPIPE; 459 break; 460 } 461 if (unp->unp_conn == NULL) 462 panic("uipc_send connected but no connection?"); 463 so2 = unp->unp_conn->unp_socket; 464 SOCKBUF_LOCK(&so2->so_rcv); 465 /* 466 * Send to paired receive port, and then reduce 467 * send buffer hiwater marks to maintain backpressure. 468 * Wake up readers. 469 */ 470 if (control != NULL) { 471 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 472 control = NULL; 473 } else { 474 sbappend_locked(&so2->so_rcv, m); 475 } 476 so->so_snd.sb_mbmax -= 477 so2->so_rcv.sb_mbcnt - unp->unp_conn->unp_mbcnt; 478 unp->unp_conn->unp_mbcnt = so2->so_rcv.sb_mbcnt; 479 newhiwat = so->so_snd.sb_hiwat - 480 (so2->so_rcv.sb_cc - unp->unp_conn->unp_cc); 481 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 482 newhiwat, RLIM_INFINITY); 483 SOCKBUF_UNLOCK(&so->so_snd); 484 unp->unp_conn->unp_cc = so2->so_rcv.sb_cc; 485 sorwakeup_locked(so2); 486 m = NULL; 487 break; 488 489 default: 490 panic("uipc_send unknown socktype"); 491 } 492 493 /* 494 * SEND_EOF is equivalent to a SEND followed by 495 * a SHUTDOWN. 496 */ 497 if (flags & PRUS_EOF) { 498 socantsendmore(so); 499 unp_shutdown(unp); 500 } 501 UNP_UNLOCK(); 502 503dispose_release: 504 if (control != NULL && error != 0) 505 unp_dispose(control); 506 507release: 508 if (control != NULL) 509 m_freem(control); 510 if (m != NULL) 511 m_freem(m); 512 return (error); 513} 514 515static int 516uipc_sense(struct socket *so, struct stat *sb) 517{ 518 struct unpcb *unp; 519 struct socket *so2; 520 521 UNP_LOCK(); 522 unp = sotounpcb(so); 523 if (unp == NULL) { 524 UNP_UNLOCK(); 525 return (EINVAL); 526 } 527 sb->st_blksize = so->so_snd.sb_hiwat; 528 if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { 529 so2 = unp->unp_conn->unp_socket; 530 sb->st_blksize += so2->so_rcv.sb_cc; 531 } 532 sb->st_dev = NODEV; 533 if (unp->unp_ino == 0) 534 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 535 sb->st_ino = unp->unp_ino; 536 UNP_UNLOCK(); 537 return (0); 538} 539 540static int 541uipc_shutdown(struct socket *so) 542{ 543 struct unpcb *unp; 544 545 UNP_LOCK(); 546 unp = sotounpcb(so); 547 if (unp == NULL) { 548 UNP_UNLOCK(); 549 return (EINVAL); 550 } 551 socantsendmore(so); 552 unp_shutdown(unp); 553 UNP_UNLOCK(); 554 return (0); 555} 556 557static int 558uipc_sockaddr(struct socket *so, struct sockaddr **nam) 559{ 560 struct unpcb *unp; 561 const struct sockaddr *sa; 562 563 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 564 UNP_LOCK(); 565 unp = sotounpcb(so); 566 if (unp == NULL) { 567 UNP_UNLOCK(); 568 free(*nam, M_SONAME); 569 *nam = NULL; 570 return (EINVAL); 571 } 572 if (unp->unp_addr != NULL) 573 sa = (struct sockaddr *) unp->unp_addr; 574 else 575 sa = &sun_noname; 576 bcopy(sa, *nam, sa->sa_len); 577 UNP_UNLOCK(); 578 return (0); 579} 580 581struct pr_usrreqs uipc_usrreqs = { 582 .pru_abort = uipc_abort, 583 .pru_accept = uipc_accept, 584 .pru_attach = uipc_attach, 585 .pru_bind = uipc_bind, 586 .pru_connect = uipc_connect, 587 .pru_connect2 = uipc_connect2, 588 .pru_detach = uipc_detach, 589 .pru_disconnect = uipc_disconnect, 590 .pru_listen = uipc_listen, 591 .pru_peeraddr = uipc_peeraddr, 592 .pru_rcvd = uipc_rcvd, 593 .pru_send = uipc_send, 594 .pru_sense = uipc_sense, 595 .pru_shutdown = uipc_shutdown, 596 .pru_sockaddr = uipc_sockaddr, 597 .pru_sosend = sosend, 598 .pru_soreceive = soreceive, 599 .pru_sopoll = sopoll, 600}; 601 602int 603uipc_ctloutput(so, sopt) 604 struct socket *so; 605 struct sockopt *sopt; 606{ 607 struct unpcb *unp; 608 struct xucred xu; 609 int error; 610 611 switch (sopt->sopt_dir) { 612 case SOPT_GET: 613 switch (sopt->sopt_name) { 614 case LOCAL_PEERCRED: 615 error = 0; 616 UNP_LOCK(); 617 unp = sotounpcb(so); 618 if (unp == NULL) { 619 UNP_UNLOCK(); 620 error = EINVAL; 621 break; 622 } 623 if (unp->unp_flags & UNP_HAVEPC) 624 xu = unp->unp_peercred; 625 else { 626 if (so->so_type == SOCK_STREAM) 627 error = ENOTCONN; 628 else 629 error = EINVAL; 630 } 631 UNP_UNLOCK(); 632 if (error == 0) 633 error = sooptcopyout(sopt, &xu, sizeof(xu)); 634 break; 635 default: 636 error = EOPNOTSUPP; 637 break; 638 } 639 break; 640 case SOPT_SET: 641 default: 642 error = EOPNOTSUPP; 643 break; 644 } 645 return (error); 646} 647 648/* 649 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 650 * for stream sockets, although the total for sender and receiver is 651 * actually only PIPSIZ. 652 * Datagram sockets really use the sendspace as the maximum datagram size, 653 * and don't really want to reserve the sendspace. Their recvspace should 654 * be large enough for at least one max-size datagram plus address. 655 */ 656#ifndef PIPSIZ 657#define PIPSIZ 8192 658#endif 659static u_long unpst_sendspace = PIPSIZ; 660static u_long unpst_recvspace = PIPSIZ; 661static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 662static u_long unpdg_recvspace = 4*1024; 663 664static int unp_rights; /* file descriptors in flight */ 665 666SYSCTL_DECL(_net_local_stream); 667SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 668 &unpst_sendspace, 0, ""); 669SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 670 &unpst_recvspace, 0, ""); 671SYSCTL_DECL(_net_local_dgram); 672SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 673 &unpdg_sendspace, 0, ""); 674SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 675 &unpdg_recvspace, 0, ""); 676SYSCTL_DECL(_net_local); 677SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 678 679static int 680unp_attach(so) 681 struct socket *so; 682{ 683 register struct unpcb *unp; 684 int error; 685 686 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 687 switch (so->so_type) { 688 689 case SOCK_STREAM: 690 error = soreserve(so, unpst_sendspace, unpst_recvspace); 691 break; 692 693 case SOCK_DGRAM: 694 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 695 break; 696 697 default: 698 panic("unp_attach"); 699 } 700 if (error) 701 return (error); 702 } 703 unp = uma_zalloc(unp_zone, M_WAITOK); 704 if (unp == NULL) 705 return (ENOBUFS); 706 bzero(unp, sizeof *unp); 707 LIST_INIT(&unp->unp_refs); 708 unp->unp_socket = so; 709 710 UNP_LOCK(); 711 unp->unp_gencnt = ++unp_gencnt; 712 unp_count++; 713 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead 714 : &unp_shead, unp, unp_link); 715 so->so_pcb = unp; 716 UNP_UNLOCK(); 717 718 return (0); 719} 720 721static void 722unp_detach(unp) 723 register struct unpcb *unp; 724{ 725 struct vnode *vp; 726 727 UNP_LOCK_ASSERT(); 728 729 LIST_REMOVE(unp, unp_link); 730 unp->unp_gencnt = ++unp_gencnt; 731 --unp_count; 732 if ((vp = unp->unp_vnode) != NULL) { 733 /* 734 * XXXRW: should v_socket be frobbed only while holding 735 * Giant? 736 */ 737 unp->unp_vnode->v_socket = NULL; 738 unp->unp_vnode = NULL; 739 } 740 if (unp->unp_conn != NULL) 741 unp_disconnect(unp); 742 while (!LIST_EMPTY(&unp->unp_refs)) { 743 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 744 unp_drop(ref, ECONNRESET); 745 } 746 soisdisconnected(unp->unp_socket); 747 unp->unp_socket->so_pcb = NULL; 748 if (unp_rights) { 749 /* 750 * Normally the receive buffer is flushed later, 751 * in sofree, but if our receive buffer holds references 752 * to descriptors that are now garbage, we will dispose 753 * of those descriptor references after the garbage collector 754 * gets them (resulting in a "panic: closef: count < 0"). 755 */ 756 sorflush(unp->unp_socket); 757 unp_gc(); /* Will unlock UNP. */ 758 } else 759 UNP_UNLOCK(); 760 UNP_UNLOCK_ASSERT(); 761 if (unp->unp_addr != NULL) 762 FREE(unp->unp_addr, M_SONAME); 763 uma_zfree(unp_zone, unp); 764 if (vp) { 765 mtx_lock(&Giant); 766 vrele(vp); 767 mtx_unlock(&Giant); 768 } 769} 770 771static int 772unp_bind(unp, nam, td) 773 struct unpcb *unp; 774 struct sockaddr *nam; 775 struct thread *td; 776{ 777 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 778 struct vnode *vp; 779 struct mount *mp; 780 struct vattr vattr; 781 int error, namelen; 782 struct nameidata nd; 783 char *buf; 784 785 UNP_LOCK_ASSERT(); 786 787 /* 788 * XXXRW: This test-and-set of unp_vnode is non-atomic; the 789 * unlocked read here is fine, but the value of unp_vnode needs 790 * to be tested again after we do all the lookups to see if the 791 * pcb is still unbound? 792 */ 793 if (unp->unp_vnode != NULL) 794 return (EINVAL); 795 796 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 797 if (namelen <= 0) 798 return (EINVAL); 799 800 UNP_UNLOCK(); 801 802 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 803 strlcpy(buf, soun->sun_path, namelen + 1); 804 805 mtx_lock(&Giant); 806restart: 807 mtx_assert(&Giant, MA_OWNED); 808 NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, 809 buf, td); 810/* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 811 error = namei(&nd); 812 if (error) 813 goto done; 814 vp = nd.ni_vp; 815 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 816 NDFREE(&nd, NDF_ONLY_PNBUF); 817 if (nd.ni_dvp == vp) 818 vrele(nd.ni_dvp); 819 else 820 vput(nd.ni_dvp); 821 if (vp != NULL) { 822 vrele(vp); 823 error = EADDRINUSE; 824 goto done; 825 } 826 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 827 if (error) 828 goto done; 829 goto restart; 830 } 831 VATTR_NULL(&vattr); 832 vattr.va_type = VSOCK; 833 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 834#ifdef MAC 835 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 836 &vattr); 837#endif 838 if (error == 0) { 839 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 840 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 841 } 842 NDFREE(&nd, NDF_ONLY_PNBUF); 843 vput(nd.ni_dvp); 844 if (error) 845 goto done; 846 vp = nd.ni_vp; 847 ASSERT_VOP_LOCKED(vp, "unp_bind"); 848 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 849 UNP_LOCK(); 850 vp->v_socket = unp->unp_socket; 851 unp->unp_vnode = vp; 852 unp->unp_addr = soun; 853 UNP_UNLOCK(); 854 VOP_UNLOCK(vp, 0, td); 855 vn_finished_write(mp); 856done: 857 mtx_unlock(&Giant); 858 free(buf, M_TEMP); 859 UNP_LOCK(); 860 return (error); 861} 862 863static int 864unp_connect(so, nam, td) 865 struct socket *so; 866 struct sockaddr *nam; 867 struct thread *td; 868{ 869 register struct sockaddr_un *soun = (struct sockaddr_un *)nam; 870 register struct vnode *vp; 871 register struct socket *so2, *so3; 872 struct unpcb *unp, *unp2, *unp3; 873 int error, len; 874 struct nameidata nd; 875 char buf[SOCK_MAXADDRLEN]; 876 struct sockaddr *sa; 877 878 UNP_LOCK_ASSERT(); 879 unp = sotounpcb(so); 880 881 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 882 if (len <= 0) 883 return (EINVAL); 884 strlcpy(buf, soun->sun_path, len + 1); 885 UNP_UNLOCK(); 886 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 887 mtx_lock(&Giant); 888 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); 889 error = namei(&nd); 890 if (error) 891 vp = NULL; 892 else 893 vp = nd.ni_vp; 894 ASSERT_VOP_LOCKED(vp, "unp_connect"); 895 NDFREE(&nd, NDF_ONLY_PNBUF); 896 if (error) 897 goto bad; 898 899 if (vp->v_type != VSOCK) { 900 error = ENOTSOCK; 901 goto bad; 902 } 903 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 904 if (error) 905 goto bad; 906 mtx_unlock(&Giant); 907 UNP_LOCK(); 908 unp = sotounpcb(so); 909 if (unp == NULL) { 910 /* 911 * XXXRW: Temporary debugging printf. 912 */ 913 printf("unp_connect(): lost race to another thread\n"); 914 error = EINVAL; 915 goto bad2; 916 } 917 so2 = vp->v_socket; 918 if (so2 == NULL) { 919 error = ECONNREFUSED; 920 goto bad2; 921 } 922 if (so->so_type != so2->so_type) { 923 error = EPROTOTYPE; 924 goto bad2; 925 } 926 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 927 if (so2->so_options & SO_ACCEPTCONN) { 928 /* 929 * NB: drop locks here so unp_attach is entered 930 * w/o locks; this avoids a recursive lock 931 * of the head and holding sleep locks across 932 * a (potentially) blocking malloc. 933 */ 934 UNP_UNLOCK(); 935 so3 = sonewconn(so2, 0); 936 UNP_LOCK(); 937 } else 938 so3 = NULL; 939 if (so3 == NULL) { 940 error = ECONNREFUSED; 941 goto bad2; 942 } 943 unp = sotounpcb(so); 944 unp2 = sotounpcb(so2); 945 unp3 = sotounpcb(so3); 946 if (unp2->unp_addr != NULL) { 947 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 948 unp3->unp_addr = (struct sockaddr_un *) sa; 949 sa = NULL; 950 } 951 /* 952 * unp_peercred management: 953 * 954 * The connecter's (client's) credentials are copied 955 * from its process structure at the time of connect() 956 * (which is now). 957 */ 958 cru2x(td->td_ucred, &unp3->unp_peercred); 959 unp3->unp_flags |= UNP_HAVEPC; 960 /* 961 * The receiver's (server's) credentials are copied 962 * from the unp_peercred member of socket on which the 963 * former called listen(); unp_listen() cached that 964 * process's credentials at that time so we can use 965 * them now. 966 */ 967 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 968 ("unp_connect: listener without cached peercred")); 969 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 970 sizeof(unp->unp_peercred)); 971 unp->unp_flags |= UNP_HAVEPC; 972#ifdef MAC 973 SOCK_LOCK(so); 974 mac_set_socket_peer_from_socket(so, so3); 975 mac_set_socket_peer_from_socket(so3, so); 976 SOCK_UNLOCK(so); 977#endif 978 979 so2 = so3; 980 } 981 error = unp_connect2(so, so2); 982bad2: 983 UNP_UNLOCK(); 984 mtx_lock(&Giant); 985bad: 986 mtx_assert(&Giant, MA_OWNED); 987 if (vp != NULL) 988 vput(vp); 989 mtx_unlock(&Giant); 990 free(sa, M_SONAME); 991 UNP_LOCK(); 992 return (error); 993} 994 995static int 996unp_connect2(so, so2) 997 register struct socket *so; 998 register struct socket *so2; 999{ 1000 register struct unpcb *unp = sotounpcb(so); 1001 register struct unpcb *unp2; 1002 1003 UNP_LOCK_ASSERT(); 1004 1005 if (so2->so_type != so->so_type) 1006 return (EPROTOTYPE); 1007 unp2 = sotounpcb(so2); 1008 unp->unp_conn = unp2; 1009 switch (so->so_type) { 1010 1011 case SOCK_DGRAM: 1012 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 1013 soisconnected(so); 1014 break; 1015 1016 case SOCK_STREAM: 1017 unp2->unp_conn = unp; 1018 soisconnected(so); 1019 soisconnected(so2); 1020 break; 1021 1022 default: 1023 panic("unp_connect2"); 1024 } 1025 return (0); 1026} 1027 1028static void 1029unp_disconnect(unp) 1030 struct unpcb *unp; 1031{ 1032 register struct unpcb *unp2 = unp->unp_conn; 1033 struct socket *so; 1034 1035 UNP_LOCK_ASSERT(); 1036 1037 if (unp2 == NULL) 1038 return; 1039 unp->unp_conn = NULL; 1040 switch (unp->unp_socket->so_type) { 1041 1042 case SOCK_DGRAM: 1043 LIST_REMOVE(unp, unp_reflink); 1044 so = unp->unp_socket; 1045 SOCK_LOCK(so); 1046 so->so_state &= ~SS_ISCONNECTED; 1047 SOCK_UNLOCK(so); 1048 break; 1049 1050 case SOCK_STREAM: 1051 soisdisconnected(unp->unp_socket); 1052 unp2->unp_conn = NULL; 1053 soisdisconnected(unp2->unp_socket); 1054 break; 1055 } 1056} 1057 1058#ifdef notdef 1059void 1060unp_abort(unp) 1061 struct unpcb *unp; 1062{ 1063 1064 unp_detach(unp); 1065 UNP_UNLOCK_ASSERT(); 1066} 1067#endif 1068 1069/* 1070 * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed 1071 * by the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers 1072 * are safe to reference. It first scans the list of struct unpcb's to 1073 * generate a pointer list, then it rescans its list one entry at a time to 1074 * externalize and copyout. It checks the generation number to see if a 1075 * struct unpcb has been reused, and will skip it if so. 1076 */ 1077static int 1078unp_pcblist(SYSCTL_HANDLER_ARGS) 1079{ 1080 int error, i, n; 1081 struct unpcb *unp, **unp_list; 1082 unp_gen_t gencnt; 1083 struct xunpgen *xug; 1084 struct unp_head *head; 1085 struct xunpcb *xu; 1086 1087 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1088 1089 /* 1090 * The process of preparing the PCB list is too time-consuming and 1091 * resource-intensive to repeat twice on every request. 1092 */ 1093 if (req->oldptr == NULL) { 1094 n = unp_count; 1095 req->oldidx = 2 * (sizeof *xug) 1096 + (n + n/8) * sizeof(struct xunpcb); 1097 return (0); 1098 } 1099 1100 if (req->newptr != NULL) 1101 return (EPERM); 1102 1103 /* 1104 * OK, now we're committed to doing something. 1105 */ 1106 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1107 UNP_LOCK(); 1108 gencnt = unp_gencnt; 1109 n = unp_count; 1110 UNP_UNLOCK(); 1111 1112 xug->xug_len = sizeof *xug; 1113 xug->xug_count = n; 1114 xug->xug_gen = gencnt; 1115 xug->xug_sogen = so_gencnt; 1116 error = SYSCTL_OUT(req, xug, sizeof *xug); 1117 if (error) { 1118 free(xug, M_TEMP); 1119 return (error); 1120 } 1121 1122 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1123 1124 UNP_LOCK(); 1125 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1126 unp = LIST_NEXT(unp, unp_link)) { 1127 if (unp->unp_gencnt <= gencnt) { 1128 if (cr_cansee(req->td->td_ucred, 1129 unp->unp_socket->so_cred)) 1130 continue; 1131 unp_list[i++] = unp; 1132 } 1133 } 1134 UNP_UNLOCK(); 1135 n = i; /* in case we lost some during malloc */ 1136 1137 error = 0; 1138 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK); 1139 for (i = 0; i < n; i++) { 1140 unp = unp_list[i]; 1141 if (unp->unp_gencnt <= gencnt) { 1142 xu->xu_len = sizeof *xu; 1143 xu->xu_unpp = unp; 1144 /* 1145 * XXX - need more locking here to protect against 1146 * connect/disconnect races for SMP. 1147 */ 1148 if (unp->unp_addr != NULL) 1149 bcopy(unp->unp_addr, &xu->xu_addr, 1150 unp->unp_addr->sun_len); 1151 if (unp->unp_conn != NULL && 1152 unp->unp_conn->unp_addr != NULL) 1153 bcopy(unp->unp_conn->unp_addr, 1154 &xu->xu_caddr, 1155 unp->unp_conn->unp_addr->sun_len); 1156 bcopy(unp, &xu->xu_unp, sizeof *unp); 1157 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1158 error = SYSCTL_OUT(req, xu, sizeof *xu); 1159 } 1160 } 1161 free(xu, M_TEMP); 1162 if (!error) { 1163 /* 1164 * Give the user an updated idea of our state. 1165 * If the generation differs from what we told 1166 * her before, she knows that something happened 1167 * while we were processing this request, and it 1168 * might be necessary to retry. 1169 */ 1170 xug->xug_gen = unp_gencnt; 1171 xug->xug_sogen = so_gencnt; 1172 xug->xug_count = unp_count; 1173 error = SYSCTL_OUT(req, xug, sizeof *xug); 1174 } 1175 free(unp_list, M_TEMP); 1176 free(xug, M_TEMP); 1177 return (error); 1178} 1179 1180SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1181 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1182 "List of active local datagram sockets"); 1183SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1184 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1185 "List of active local stream sockets"); 1186 1187static void 1188unp_shutdown(unp) 1189 struct unpcb *unp; 1190{ 1191 struct socket *so; 1192 1193 UNP_LOCK_ASSERT(); 1194 1195 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1196 (so = unp->unp_conn->unp_socket)) 1197 socantrcvmore(so); 1198} 1199 1200static void 1201unp_drop(unp, errno) 1202 struct unpcb *unp; 1203 int errno; 1204{ 1205 struct socket *so = unp->unp_socket; 1206 1207 UNP_LOCK_ASSERT(); 1208 1209 so->so_error = errno; 1210 unp_disconnect(unp); 1211} 1212 1213#ifdef notdef 1214void 1215unp_drain() 1216{ 1217 1218} 1219#endif 1220 1221static void 1222unp_freerights(rp, fdcount) 1223 struct file **rp; 1224 int fdcount; 1225{ 1226 int i; 1227 struct file *fp; 1228 1229 for (i = 0; i < fdcount; i++) { 1230 fp = *rp; 1231 /* 1232 * zero the pointer before calling 1233 * unp_discard since it may end up 1234 * in unp_gc().. 1235 */ 1236 *rp++ = 0; 1237 unp_discard(fp); 1238 } 1239} 1240 1241int 1242unp_externalize(control, controlp) 1243 struct mbuf *control, **controlp; 1244{ 1245 struct thread *td = curthread; /* XXX */ 1246 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1247 int i; 1248 int *fdp; 1249 struct file **rp; 1250 struct file *fp; 1251 void *data; 1252 socklen_t clen = control->m_len, datalen; 1253 int error, newfds; 1254 int f; 1255 u_int newlen; 1256 1257 UNP_UNLOCK_ASSERT(); 1258 1259 error = 0; 1260 if (controlp != NULL) /* controlp == NULL => free control messages */ 1261 *controlp = NULL; 1262 1263 while (cm != NULL) { 1264 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1265 error = EINVAL; 1266 break; 1267 } 1268 1269 data = CMSG_DATA(cm); 1270 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1271 1272 if (cm->cmsg_level == SOL_SOCKET 1273 && cm->cmsg_type == SCM_RIGHTS) { 1274 newfds = datalen / sizeof(struct file *); 1275 rp = data; 1276 1277 /* If we're not outputting the descriptors free them. */ 1278 if (error || controlp == NULL) { 1279 unp_freerights(rp, newfds); 1280 goto next; 1281 } 1282 FILEDESC_LOCK(td->td_proc->p_fd); 1283 /* if the new FD's will not fit free them. */ 1284 if (!fdavail(td, newfds)) { 1285 FILEDESC_UNLOCK(td->td_proc->p_fd); 1286 error = EMSGSIZE; 1287 unp_freerights(rp, newfds); 1288 goto next; 1289 } 1290 /* 1291 * now change each pointer to an fd in the global 1292 * table to an integer that is the index to the 1293 * local fd table entry that we set up to point 1294 * to the global one we are transferring. 1295 */ 1296 newlen = newfds * sizeof(int); 1297 *controlp = sbcreatecontrol(NULL, newlen, 1298 SCM_RIGHTS, SOL_SOCKET); 1299 if (*controlp == NULL) { 1300 FILEDESC_UNLOCK(td->td_proc->p_fd); 1301 error = E2BIG; 1302 unp_freerights(rp, newfds); 1303 goto next; 1304 } 1305 1306 fdp = (int *) 1307 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1308 for (i = 0; i < newfds; i++) { 1309 if (fdalloc(td, 0, &f)) 1310 panic("unp_externalize fdalloc failed"); 1311 fp = *rp++; 1312 td->td_proc->p_fd->fd_ofiles[f] = fp; 1313 FILE_LOCK(fp); 1314 fp->f_msgcount--; 1315 FILE_UNLOCK(fp); 1316 unp_rights--; 1317 *fdp++ = f; 1318 } 1319 FILEDESC_UNLOCK(td->td_proc->p_fd); 1320 } else { /* We can just copy anything else across */ 1321 if (error || controlp == NULL) 1322 goto next; 1323 *controlp = sbcreatecontrol(NULL, datalen, 1324 cm->cmsg_type, cm->cmsg_level); 1325 if (*controlp == NULL) { 1326 error = ENOBUFS; 1327 goto next; 1328 } 1329 bcopy(data, 1330 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1331 datalen); 1332 } 1333 1334 controlp = &(*controlp)->m_next; 1335 1336next: 1337 if (CMSG_SPACE(datalen) < clen) { 1338 clen -= CMSG_SPACE(datalen); 1339 cm = (struct cmsghdr *) 1340 ((caddr_t)cm + CMSG_SPACE(datalen)); 1341 } else { 1342 clen = 0; 1343 cm = NULL; 1344 } 1345 } 1346 1347 m_freem(control); 1348 1349 return (error); 1350} 1351 1352void 1353unp_init(void) 1354{ 1355 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1356 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 1357 if (unp_zone == NULL) 1358 panic("unp_init"); 1359 uma_zone_set_max(unp_zone, nmbclusters); 1360 LIST_INIT(&unp_dhead); 1361 LIST_INIT(&unp_shead); 1362 1363 UNP_LOCK_INIT(); 1364} 1365 1366static int 1367unp_internalize(controlp, td) 1368 struct mbuf **controlp; 1369 struct thread *td; 1370{ 1371 struct mbuf *control = *controlp; 1372 struct proc *p = td->td_proc; 1373 struct filedesc *fdescp = p->p_fd; 1374 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1375 struct cmsgcred *cmcred; 1376 struct file **rp; 1377 struct file *fp; 1378 struct timeval *tv; 1379 int i, fd, *fdp; 1380 void *data; 1381 socklen_t clen = control->m_len, datalen; 1382 int error, oldfds; 1383 u_int newlen; 1384 1385 UNP_UNLOCK_ASSERT(); 1386 1387 error = 0; 1388 *controlp = NULL; 1389 1390 while (cm != NULL) { 1391 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1392 || cm->cmsg_len > clen) { 1393 error = EINVAL; 1394 goto out; 1395 } 1396 1397 data = CMSG_DATA(cm); 1398 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1399 1400 switch (cm->cmsg_type) { 1401 /* 1402 * Fill in credential information. 1403 */ 1404 case SCM_CREDS: 1405 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1406 SCM_CREDS, SOL_SOCKET); 1407 if (*controlp == NULL) { 1408 error = ENOBUFS; 1409 goto out; 1410 } 1411 1412 cmcred = (struct cmsgcred *) 1413 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1414 cmcred->cmcred_pid = p->p_pid; 1415 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1416 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1417 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1418 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1419 CMGROUP_MAX); 1420 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1421 cmcred->cmcred_groups[i] = 1422 td->td_ucred->cr_groups[i]; 1423 break; 1424 1425 case SCM_RIGHTS: 1426 oldfds = datalen / sizeof (int); 1427 /* 1428 * check that all the FDs passed in refer to legal files 1429 * If not, reject the entire operation. 1430 */ 1431 fdp = data; 1432 FILEDESC_LOCK(fdescp); 1433 for (i = 0; i < oldfds; i++) { 1434 fd = *fdp++; 1435 if ((unsigned)fd >= fdescp->fd_nfiles || 1436 fdescp->fd_ofiles[fd] == NULL) { 1437 FILEDESC_UNLOCK(fdescp); 1438 error = EBADF; 1439 goto out; 1440 } 1441 fp = fdescp->fd_ofiles[fd]; 1442 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1443 FILEDESC_UNLOCK(fdescp); 1444 error = EOPNOTSUPP; 1445 goto out; 1446 } 1447 1448 } 1449 /* 1450 * Now replace the integer FDs with pointers to 1451 * the associated global file table entry.. 1452 */ 1453 newlen = oldfds * sizeof(struct file *); 1454 *controlp = sbcreatecontrol(NULL, newlen, 1455 SCM_RIGHTS, SOL_SOCKET); 1456 if (*controlp == NULL) { 1457 FILEDESC_UNLOCK(fdescp); 1458 error = E2BIG; 1459 goto out; 1460 } 1461 1462 fdp = data; 1463 rp = (struct file **) 1464 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1465 for (i = 0; i < oldfds; i++) { 1466 fp = fdescp->fd_ofiles[*fdp++]; 1467 *rp++ = fp; 1468 FILE_LOCK(fp); 1469 fp->f_count++; 1470 fp->f_msgcount++; 1471 FILE_UNLOCK(fp); 1472 unp_rights++; 1473 } 1474 FILEDESC_UNLOCK(fdescp); 1475 break; 1476 1477 case SCM_TIMESTAMP: 1478 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1479 SCM_TIMESTAMP, SOL_SOCKET); 1480 if (*controlp == NULL) { 1481 error = ENOBUFS; 1482 goto out; 1483 } 1484 tv = (struct timeval *) 1485 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1486 microtime(tv); 1487 break; 1488 1489 default: 1490 error = EINVAL; 1491 goto out; 1492 } 1493 1494 controlp = &(*controlp)->m_next; 1495 1496 if (CMSG_SPACE(datalen) < clen) { 1497 clen -= CMSG_SPACE(datalen); 1498 cm = (struct cmsghdr *) 1499 ((caddr_t)cm + CMSG_SPACE(datalen)); 1500 } else { 1501 clen = 0; 1502 cm = NULL; 1503 } 1504 } 1505 1506out: 1507 m_freem(control); 1508 1509 return (error); 1510} 1511 1512/* 1513 * unp_defer is thread-local during garbage collection, and does not require 1514 * explicit synchronization. unp_gcing prevents other threads from entering 1515 * garbage collection, and perhaps should be an sx lock instead. 1516 */ 1517static int unp_defer, unp_gcing; 1518 1519static void 1520unp_gc() 1521{ 1522 register struct file *fp, *nextfp; 1523 register struct socket *so; 1524 struct file **extra_ref, **fpp; 1525 int nunref, i; 1526 int nfiles_snap; 1527 int nfiles_slack = 20; 1528 1529 UNP_LOCK_ASSERT(); 1530 1531 if (unp_gcing) { 1532 UNP_UNLOCK(); 1533 return; 1534 } 1535 unp_gcing = 1; 1536 unp_defer = 0; 1537 UNP_UNLOCK(); 1538 /* 1539 * before going through all this, set all FDs to 1540 * be NOT defered and NOT externally accessible 1541 */ 1542 sx_slock(&filelist_lock); 1543 LIST_FOREACH(fp, &filehead, f_list) 1544 fp->f_gcflag &= ~(FMARK|FDEFER); 1545 do { 1546 LIST_FOREACH(fp, &filehead, f_list) { 1547 FILE_LOCK(fp); 1548 /* 1549 * If the file is not open, skip it 1550 */ 1551 if (fp->f_count == 0) { 1552 FILE_UNLOCK(fp); 1553 continue; 1554 } 1555 /* 1556 * If we already marked it as 'defer' in a 1557 * previous pass, then try process it this time 1558 * and un-mark it 1559 */ 1560 if (fp->f_gcflag & FDEFER) { 1561 fp->f_gcflag &= ~FDEFER; 1562 unp_defer--; 1563 } else { 1564 /* 1565 * if it's not defered, then check if it's 1566 * already marked.. if so skip it 1567 */ 1568 if (fp->f_gcflag & FMARK) { 1569 FILE_UNLOCK(fp); 1570 continue; 1571 } 1572 /* 1573 * If all references are from messages 1574 * in transit, then skip it. it's not 1575 * externally accessible. 1576 */ 1577 if (fp->f_count == fp->f_msgcount) { 1578 FILE_UNLOCK(fp); 1579 continue; 1580 } 1581 /* 1582 * If it got this far then it must be 1583 * externally accessible. 1584 */ 1585 fp->f_gcflag |= FMARK; 1586 } 1587 /* 1588 * either it was defered, or it is externally 1589 * accessible and not already marked so. 1590 * Now check if it is possibly one of OUR sockets. 1591 */ 1592 if (fp->f_type != DTYPE_SOCKET || 1593 (so = fp->f_data) == NULL) { 1594 FILE_UNLOCK(fp); 1595 continue; 1596 } 1597 FILE_UNLOCK(fp); 1598 if (so->so_proto->pr_domain != &localdomain || 1599 (so->so_proto->pr_flags&PR_RIGHTS) == 0) 1600 continue; 1601#ifdef notdef 1602 if (so->so_rcv.sb_flags & SB_LOCK) { 1603 /* 1604 * This is problematical; it's not clear 1605 * we need to wait for the sockbuf to be 1606 * unlocked (on a uniprocessor, at least), 1607 * and it's also not clear what to do 1608 * if sbwait returns an error due to receipt 1609 * of a signal. If sbwait does return 1610 * an error, we'll go into an infinite 1611 * loop. Delete all of this for now. 1612 */ 1613 (void) sbwait(&so->so_rcv); 1614 goto restart; 1615 } 1616#endif 1617 /* 1618 * So, Ok, it's one of our sockets and it IS externally 1619 * accessible (or was defered). Now we look 1620 * to see if we hold any file descriptors in its 1621 * message buffers. Follow those links and mark them 1622 * as accessible too. 1623 */ 1624 SOCKBUF_LOCK(&so->so_rcv); 1625 unp_scan(so->so_rcv.sb_mb, unp_mark); 1626 SOCKBUF_UNLOCK(&so->so_rcv); 1627 } 1628 } while (unp_defer); 1629 sx_sunlock(&filelist_lock); 1630 /* 1631 * We grab an extra reference to each of the file table entries 1632 * that are not otherwise accessible and then free the rights 1633 * that are stored in messages on them. 1634 * 1635 * The bug in the orginal code is a little tricky, so I'll describe 1636 * what's wrong with it here. 1637 * 1638 * It is incorrect to simply unp_discard each entry for f_msgcount 1639 * times -- consider the case of sockets A and B that contain 1640 * references to each other. On a last close of some other socket, 1641 * we trigger a gc since the number of outstanding rights (unp_rights) 1642 * is non-zero. If during the sweep phase the gc code un_discards, 1643 * we end up doing a (full) closef on the descriptor. A closef on A 1644 * results in the following chain. Closef calls soo_close, which 1645 * calls soclose. Soclose calls first (through the switch 1646 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1647 * returns because the previous instance had set unp_gcing, and 1648 * we return all the way back to soclose, which marks the socket 1649 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1650 * to free up the rights that are queued in messages on the socket A, 1651 * i.e., the reference on B. The sorflush calls via the dom_dispose 1652 * switch unp_dispose, which unp_scans with unp_discard. This second 1653 * instance of unp_discard just calls closef on B. 1654 * 1655 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1656 * which results in another closef on A. Unfortunately, A is already 1657 * being closed, and the descriptor has already been marked with 1658 * SS_NOFDREF, and soclose panics at this point. 1659 * 1660 * Here, we first take an extra reference to each inaccessible 1661 * descriptor. Then, we call sorflush ourself, since we know 1662 * it is a Unix domain socket anyhow. After we destroy all the 1663 * rights carried in messages, we do a last closef to get rid 1664 * of our extra reference. This is the last close, and the 1665 * unp_detach etc will shut down the socket. 1666 * 1667 * 91/09/19, bsy@cs.cmu.edu 1668 */ 1669again: 1670 nfiles_snap = openfiles + nfiles_slack; /* some slack */ 1671 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 1672 M_WAITOK); 1673 sx_slock(&filelist_lock); 1674 if (nfiles_snap < openfiles) { 1675 sx_sunlock(&filelist_lock); 1676 free(extra_ref, M_TEMP); 1677 nfiles_slack += 20; 1678 goto again; 1679 } 1680 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 1681 fp != NULL; fp = nextfp) { 1682 nextfp = LIST_NEXT(fp, f_list); 1683 FILE_LOCK(fp); 1684 /* 1685 * If it's not open, skip it 1686 */ 1687 if (fp->f_count == 0) { 1688 FILE_UNLOCK(fp); 1689 continue; 1690 } 1691 /* 1692 * If all refs are from msgs, and it's not marked accessible 1693 * then it must be referenced from some unreachable cycle 1694 * of (shut-down) FDs, so include it in our 1695 * list of FDs to remove 1696 */ 1697 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 1698 *fpp++ = fp; 1699 nunref++; 1700 fp->f_count++; 1701 } 1702 FILE_UNLOCK(fp); 1703 } 1704 sx_sunlock(&filelist_lock); 1705 /* 1706 * for each FD on our hit list, do the following two things 1707 */ 1708 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1709 struct file *tfp = *fpp; 1710 FILE_LOCK(tfp); 1711 if (tfp->f_type == DTYPE_SOCKET && 1712 tfp->f_data != NULL) { 1713 FILE_UNLOCK(tfp); 1714 sorflush(tfp->f_data); 1715 } else { 1716 FILE_UNLOCK(tfp); 1717 } 1718 } 1719 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) 1720 closef(*fpp, (struct thread *) NULL); 1721 free(extra_ref, M_TEMP); 1722 unp_gcing = 0; 1723 1724 UNP_UNLOCK_ASSERT(); 1725} 1726 1727void 1728unp_dispose(m) 1729 struct mbuf *m; 1730{ 1731 1732 if (m) 1733 unp_scan(m, unp_discard); 1734} 1735 1736static int 1737unp_listen(unp, td) 1738 struct unpcb *unp; 1739 struct thread *td; 1740{ 1741 UNP_LOCK_ASSERT(); 1742 1743 /* 1744 * XXXRW: Why populate the local peer cred with our own credential? 1745 */ 1746 cru2x(td->td_ucred, &unp->unp_peercred); 1747 unp->unp_flags |= UNP_HAVEPCCACHED; 1748 return (0); 1749} 1750 1751static void 1752unp_scan(m0, op) 1753 register struct mbuf *m0; 1754 void (*op)(struct file *); 1755{ 1756 struct mbuf *m; 1757 struct file **rp; 1758 struct cmsghdr *cm; 1759 void *data; 1760 int i; 1761 socklen_t clen, datalen; 1762 int qfds; 1763 1764 while (m0 != NULL) { 1765 for (m = m0; m; m = m->m_next) { 1766 if (m->m_type != MT_CONTROL) 1767 continue; 1768 1769 cm = mtod(m, struct cmsghdr *); 1770 clen = m->m_len; 1771 1772 while (cm != NULL) { 1773 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 1774 break; 1775 1776 data = CMSG_DATA(cm); 1777 datalen = (caddr_t)cm + cm->cmsg_len 1778 - (caddr_t)data; 1779 1780 if (cm->cmsg_level == SOL_SOCKET && 1781 cm->cmsg_type == SCM_RIGHTS) { 1782 qfds = datalen / sizeof (struct file *); 1783 rp = data; 1784 for (i = 0; i < qfds; i++) 1785 (*op)(*rp++); 1786 } 1787 1788 if (CMSG_SPACE(datalen) < clen) { 1789 clen -= CMSG_SPACE(datalen); 1790 cm = (struct cmsghdr *) 1791 ((caddr_t)cm + CMSG_SPACE(datalen)); 1792 } else { 1793 clen = 0; 1794 cm = NULL; 1795 } 1796 } 1797 } 1798 m0 = m0->m_act; 1799 } 1800} 1801 1802static void 1803unp_mark(fp) 1804 struct file *fp; 1805{ 1806 if (fp->f_gcflag & FMARK) 1807 return; 1808 unp_defer++; 1809 fp->f_gcflag |= (FMARK|FDEFER); 1810} 1811 1812static void 1813unp_discard(fp) 1814 struct file *fp; 1815{ 1816 FILE_LOCK(fp); 1817 fp->f_msgcount--; 1818 unp_rights--; 1819 FILE_UNLOCK(fp); 1820 (void) closef(fp, (struct thread *)NULL); 1821} 1822