1 /* 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94 30 * $FreeBSD: src/sys/kern/uipc_usrreq.c,v 1.54.2.10 2003/03/04 17:28:09 nectar Exp $ 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/domain.h> 37 #include <sys/fcntl.h> 38 #include <sys/malloc.h> /* XXX must be before <sys/file.h> */ 39 #include <sys/proc.h> 40 #include <sys/file.h> 41 #include <sys/filedesc.h> 42 #include <sys/mbuf.h> 43 #include <sys/nlookup.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/resourcevar.h> 48 #include <sys/stat.h> 49 #include <sys/mount.h> 50 #include <sys/sysctl.h> 51 #include <sys/un.h> 52 #include <sys/unpcb.h> 53 #include <sys/vnode.h> 54 #include <sys/kern_syscall.h> 55 #include <sys/taskqueue.h> 56 57 #include <sys/file2.h> 58 #include <sys/spinlock2.h> 59 #include <sys/socketvar2.h> 60 #include <sys/msgport2.h> 61 62 /* 63 * Unix communications domain. 64 * 65 * TODO: 66 * RDM 67 * rethink name space problems 68 * need a proper out-of-band 69 * lock pushdown 70 * 71 * 72 * Unix domain sockets GC. 73 * 74 * It was originally designed to address following three cases: 75 * 1) Receiving unix domain socket can not accept the rights, e.g. 76 * when the so_rcv is full. 77 * 2) Caller of recvmsg(2) does not pass buffer to receive rights. 78 * 3) Unix domain sockets loop reference, e.g. s1 is on s2.so_rcv, 79 * while s2 on s1.so_rcv. 80 * 81 * Code under UNP_GC_ALLFILES is intended to address all above three 82 * cases. However, 1) was addressed a long time ago in uipc_send() 83 * (we inheritted the fix from FreeBSD when DragonFly forked). 2) 84 * was addressed in soreceive() by git-e62cfe62. 3) is the only 85 * case that needs GC. The new code (!UNP_GC_ALLFILES) addresses 86 * case 3) in the following way: 87 * - Record the struct file in unpcb, if the Unix domain socket is 88 * passed as one of the rights. 89 * - At GC time, only unpcbs are scanned, and only Unix domain sockets 90 * that are still used as rights are potential GC targets. 91 */ 92 93 #define UNP_DETACHED UNP_PRIVATE1 94 #define UNP_CONNECTING UNP_PRIVATE2 95 #define UNP_DROPPED UNP_PRIVATE3 96 #define UNP_MARKER UNP_PRIVATE4 97 98 #define UNPGC_REF 0x1 /* unpcb has external ref. */ 99 #define UNPGC_DEAD 0x2 /* unpcb might be dead. */ 100 #define UNPGC_SCANNED 0x4 /* Has been scanned. */ 101 102 #define UNP_GCFILE_MAX 256 103 104 /* For unp_internalize() and unp_externalize() */ 105 CTASSERT(sizeof(struct file *) >= sizeof(int)); 106 107 #define UNP_ISATTACHED(unp) \ 108 ((unp) != NULL && ((unp)->unp_flags & UNP_DETACHED) == 0) 109 110 #ifdef INVARIANTS 111 #define UNP_ASSERT_TOKEN_HELD(unp) \ 112 ASSERT_LWKT_TOKEN_HELD(lwkt_token_pool_lookup((unp))) 113 #else /* !INVARIANTS */ 114 #define UNP_ASSERT_TOKEN_HELD(unp) 115 #endif /* INVARIANTS */ 116 117 struct unp_defdiscard { 118 SLIST_ENTRY(unp_defdiscard) next; 119 struct file *fp; 120 }; 121 SLIST_HEAD(unp_defdiscard_list, unp_defdiscard); 122 123 TAILQ_HEAD(unpcb_qhead, unpcb); 124 struct unp_global_head { 125 struct unpcb_qhead list; 126 int count; 127 }; 128 129 static MALLOC_DEFINE(M_UNPCB, "unpcb", "unpcb struct"); 130 static unp_gen_t unp_gencnt; 131 132 static struct unp_global_head unp_stream_head; 133 static struct unp_global_head unp_dgram_head; 134 static struct unp_global_head unp_seqpkt_head; 135 136 static struct unp_global_head * const unp_heads[] = 137 { &unp_stream_head, &unp_dgram_head, &unp_seqpkt_head, NULL }; 138 139 static struct lwkt_token unp_token = LWKT_TOKEN_INITIALIZER(unp_token); 140 static struct taskqueue *unp_taskqueue; 141 142 static struct unp_defdiscard_list unp_defdiscard_head; 143 static struct spinlock unp_defdiscard_spin; 144 static struct task unp_defdiscard_task; 145 146 static struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; 147 static ino_t unp_ino = 1; /* prototype for fake inode numbers */ 148 149 static int unp_attach (struct socket *, struct pru_attach_info *); 150 static void unp_detach (struct unpcb *); 151 static int unp_bind (struct unpcb *,struct sockaddr *, struct thread *); 152 static int unp_connect (struct socket *,struct sockaddr *, 153 struct thread *); 154 static void unp_disconnect(struct unpcb *, int); 155 static void unp_shutdown (struct unpcb *); 156 static void unp_gc(void *, int); 157 #ifdef UNP_GC_ALLFILES 158 static int unp_gc_clearmarks(struct file *, void *); 159 static int unp_gc_checkmarks(struct file *, void *); 160 static int unp_gc_checkrefs(struct file *, void *); 161 static void unp_mark(struct file *, void *data); 162 #endif 163 static void unp_scan (struct mbuf *, void (*)(struct file *, void *), 164 void *data); 165 static void unp_discard (struct file *, void *); 166 static int unp_internalize (struct mbuf *, struct thread *); 167 static int unp_listen (struct unpcb *, struct thread *); 168 static void unp_fp_externalize(struct lwp *lp, struct file *fp, int fd, 169 int flags); 170 static int unp_find_lockref(struct sockaddr *nam, struct thread *td, 171 short type, struct unpcb **unp_ret); 172 static int unp_connect_pair(struct unpcb *unp, struct unpcb *unp2); 173 static void unp_drop(struct unpcb *unp, int error); 174 static void unp_defdiscard_taskfunc(void *, int); 175 176 static int unp_rights; /* file descriptors in flight */ 177 static struct lwkt_token unp_rights_token = 178 LWKT_TOKEN_INITIALIZER(unp_rights_token); 179 static struct task unp_gc_task; 180 static struct unpcb *unp_gc_marker; 181 182 SYSCTL_DECL(_net_local); 183 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, 184 "File descriptors in flight"); 185 186 /* 187 * SMP Considerations: 188 * 189 * Since unp_token will be automaticly released upon execution of 190 * blocking code, we need to reference unp_conn before any possible 191 * blocking code to prevent it from being ripped behind our back. 192 * 193 * Any adjustment to unp->unp_conn requires both the global unp_token 194 * AND the per-unp token (lwkt_token_pool_lookup(unp)) to be held. 195 * 196 * Any access to so_pcb to obtain unp requires the pool token for 197 * unp to be held. 198 */ 199 200 static __inline void 201 unp_reference(struct unpcb *unp) 202 { 203 /* 0->1 transition will not work */ 204 KKASSERT(unp->unp_refcnt > 0); 205 atomic_add_int(&unp->unp_refcnt, 1); 206 } 207 208 static __inline void 209 unp_free(struct unpcb *unp) 210 { 211 KKASSERT(unp->unp_refcnt > 0); 212 if (atomic_fetchadd_int(&unp->unp_refcnt, -1) == 1) 213 unp_detach(unp); 214 } 215 216 static __inline struct unpcb * 217 unp_getsocktoken(struct socket *so) 218 { 219 struct unpcb *unp; 220 221 /* 222 * The unp pointer is invalid until we verify that it is 223 * good by re-checking so_pcb AFTER obtaining the token. 224 */ 225 while ((unp = so->so_pcb) != NULL) { 226 lwkt_getpooltoken(unp); 227 if (unp == so->so_pcb) 228 break; 229 lwkt_relpooltoken(unp); 230 } 231 return unp; 232 } 233 234 static __inline void 235 unp_reltoken(struct unpcb *unp) 236 { 237 if (unp != NULL) 238 lwkt_relpooltoken(unp); 239 } 240 241 static __inline void 242 unp_setflags(struct unpcb *unp, int flags) 243 { 244 atomic_set_int(&unp->unp_flags, flags); 245 } 246 247 static __inline void 248 unp_clrflags(struct unpcb *unp, int flags) 249 { 250 atomic_clear_int(&unp->unp_flags, flags); 251 } 252 253 static __inline struct unp_global_head * 254 unp_globalhead(short type) 255 { 256 switch (type) { 257 case SOCK_STREAM: 258 return &unp_stream_head; 259 case SOCK_DGRAM: 260 return &unp_dgram_head; 261 case SOCK_SEQPACKET: 262 return &unp_seqpkt_head; 263 default: 264 panic("unknown socket type %d", type); 265 } 266 } 267 268 static __inline struct unpcb * 269 unp_fp2unpcb(struct file *fp) 270 { 271 struct socket *so; 272 273 if (fp->f_type != DTYPE_SOCKET) 274 return NULL; 275 276 so = fp->f_data; 277 if (so == NULL) 278 return NULL; 279 280 if (so->so_proto->pr_domain != &localdomain) 281 return NULL; 282 283 return so->so_pcb; 284 } 285 286 static __inline void 287 unp_add_right(struct file *fp) 288 { 289 struct unpcb *unp; 290 291 ASSERT_LWKT_TOKEN_HELD(&unp_rights_token); 292 KASSERT(fp->f_count > 0, ("invalid f_count %d", fp->f_count)); 293 294 unp = unp_fp2unpcb(fp); 295 if (unp != NULL) { 296 unp->unp_fp = fp; 297 unp->unp_msgcount++; 298 } 299 fp->f_msgcount++; 300 unp_rights++; 301 } 302 303 static __inline void 304 unp_del_right(struct file *fp) 305 { 306 struct unpcb *unp; 307 308 ASSERT_LWKT_TOKEN_HELD(&unp_rights_token); 309 KASSERT(fp->f_count > 0, ("invalid f_count %d", fp->f_count)); 310 311 unp = unp_fp2unpcb(fp); 312 if (unp != NULL) { 313 KASSERT(unp->unp_msgcount > 0, 314 ("invalid unp msgcount %d", unp->unp_msgcount)); 315 unp->unp_msgcount--; 316 if (unp->unp_msgcount == 0) 317 unp->unp_fp = NULL; 318 } 319 fp->f_msgcount--; 320 unp_rights--; 321 } 322 323 /* 324 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort() 325 * will sofree() it when we return. 326 */ 327 static void 328 uipc_abort(netmsg_t msg) 329 { 330 struct unpcb *unp; 331 int error; 332 333 lwkt_gettoken(&unp_token); 334 unp = unp_getsocktoken(msg->base.nm_so); 335 336 if (UNP_ISATTACHED(unp)) { 337 unp_drop(unp, ECONNABORTED); 338 error = 0; 339 } else { 340 error = EINVAL; 341 } 342 343 unp_reltoken(unp); 344 lwkt_reltoken(&unp_token); 345 346 lwkt_replymsg(&msg->lmsg, error); 347 } 348 349 static void 350 uipc_accept(netmsg_t msg) 351 { 352 struct unpcb *unp; 353 int error; 354 355 lwkt_gettoken(&unp_token); 356 unp = unp_getsocktoken(msg->base.nm_so); 357 358 if (!UNP_ISATTACHED(unp)) { 359 error = EINVAL; 360 } else { 361 struct unpcb *unp2 = unp->unp_conn; 362 363 /* 364 * Pass back name of connected socket, 365 * if it was bound and we are still connected 366 * (our peer may have closed already!). 367 */ 368 if (unp2 && unp2->unp_addr) { 369 unp_reference(unp2); 370 *msg->accept.nm_nam = dup_sockaddr( 371 (struct sockaddr *)unp2->unp_addr); 372 unp_free(unp2); 373 } else { 374 *msg->accept.nm_nam = dup_sockaddr(&sun_noname); 375 } 376 error = 0; 377 } 378 379 unp_reltoken(unp); 380 lwkt_reltoken(&unp_token); 381 382 lwkt_replymsg(&msg->lmsg, error); 383 } 384 385 static void 386 uipc_attach(netmsg_t msg) 387 { 388 int error; 389 390 lwkt_gettoken(&unp_token); 391 392 KASSERT(msg->base.nm_so->so_pcb == NULL, ("double unp attach")); 393 error = unp_attach(msg->base.nm_so, msg->attach.nm_ai); 394 395 lwkt_reltoken(&unp_token); 396 lwkt_replymsg(&msg->lmsg, error); 397 } 398 399 static void 400 uipc_bind(netmsg_t msg) 401 { 402 struct unpcb *unp; 403 int error; 404 405 lwkt_gettoken(&unp_token); 406 unp = unp_getsocktoken(msg->base.nm_so); 407 408 if (UNP_ISATTACHED(unp)) 409 error = unp_bind(unp, msg->bind.nm_nam, msg->bind.nm_td); 410 else 411 error = EINVAL; 412 413 unp_reltoken(unp); 414 lwkt_reltoken(&unp_token); 415 416 lwkt_replymsg(&msg->lmsg, error); 417 } 418 419 static void 420 uipc_connect(netmsg_t msg) 421 { 422 int error; 423 424 error = unp_connect(msg->base.nm_so, msg->connect.nm_nam, 425 msg->connect.nm_td); 426 lwkt_replymsg(&msg->lmsg, error); 427 } 428 429 static void 430 uipc_connect2(netmsg_t msg) 431 { 432 int error; 433 434 error = unp_connect2(msg->connect2.nm_so1, msg->connect2.nm_so2); 435 lwkt_replymsg(&msg->lmsg, error); 436 } 437 438 /* control is EOPNOTSUPP */ 439 440 static void 441 uipc_detach(netmsg_t msg) 442 { 443 struct unpcb *unp; 444 int error; 445 446 lwkt_gettoken(&unp_token); 447 unp = unp_getsocktoken(msg->base.nm_so); 448 449 if (UNP_ISATTACHED(unp)) { 450 unp_drop(unp, 0); 451 error = 0; 452 } else { 453 error = EINVAL; 454 } 455 456 unp_reltoken(unp); 457 lwkt_reltoken(&unp_token); 458 459 lwkt_replymsg(&msg->lmsg, error); 460 } 461 462 static void 463 uipc_disconnect(netmsg_t msg) 464 { 465 struct unpcb *unp; 466 int error; 467 468 lwkt_gettoken(&unp_token); 469 unp = unp_getsocktoken(msg->base.nm_so); 470 471 if (UNP_ISATTACHED(unp)) { 472 unp_disconnect(unp, 0); 473 error = 0; 474 } else { 475 error = EINVAL; 476 } 477 478 unp_reltoken(unp); 479 lwkt_reltoken(&unp_token); 480 481 lwkt_replymsg(&msg->lmsg, error); 482 } 483 484 static void 485 uipc_listen(netmsg_t msg) 486 { 487 struct unpcb *unp; 488 int error; 489 490 lwkt_gettoken(&unp_token); 491 unp = unp_getsocktoken(msg->base.nm_so); 492 493 if (!UNP_ISATTACHED(unp) || unp->unp_vnode == NULL) 494 error = EINVAL; 495 else 496 error = unp_listen(unp, msg->listen.nm_td); 497 498 unp_reltoken(unp); 499 lwkt_reltoken(&unp_token); 500 501 lwkt_replymsg(&msg->lmsg, error); 502 } 503 504 static void 505 uipc_peeraddr(netmsg_t msg) 506 { 507 struct unpcb *unp; 508 int error; 509 510 lwkt_gettoken(&unp_token); 511 unp = unp_getsocktoken(msg->base.nm_so); 512 513 if (!UNP_ISATTACHED(unp)) { 514 error = EINVAL; 515 } else if (unp->unp_conn && unp->unp_conn->unp_addr) { 516 struct unpcb *unp2 = unp->unp_conn; 517 518 unp_reference(unp2); 519 *msg->peeraddr.nm_nam = dup_sockaddr( 520 (struct sockaddr *)unp2->unp_addr); 521 unp_free(unp2); 522 error = 0; 523 } else { 524 /* 525 * XXX: It seems that this test always fails even when 526 * connection is established. So, this else clause is 527 * added as workaround to return PF_LOCAL sockaddr. 528 */ 529 *msg->peeraddr.nm_nam = dup_sockaddr(&sun_noname); 530 error = 0; 531 } 532 533 unp_reltoken(unp); 534 lwkt_reltoken(&unp_token); 535 536 lwkt_replymsg(&msg->lmsg, error); 537 } 538 539 static void 540 uipc_rcvd(netmsg_t msg) 541 { 542 struct unpcb *unp, *unp2; 543 struct socket *so; 544 struct socket *so2; 545 int error; 546 547 /* 548 * so_pcb is only modified with both the global and the unp 549 * pool token held. 550 */ 551 so = msg->base.nm_so; 552 unp = unp_getsocktoken(so); 553 554 if (!UNP_ISATTACHED(unp)) { 555 error = EINVAL; 556 goto done; 557 } 558 559 switch (so->so_type) { 560 case SOCK_DGRAM: 561 panic("uipc_rcvd DGRAM?"); 562 /*NOTREACHED*/ 563 case SOCK_STREAM: 564 case SOCK_SEQPACKET: 565 if (unp->unp_conn == NULL) 566 break; 567 unp2 = unp->unp_conn; /* protected by pool token */ 568 569 /* 570 * Because we are transfering mbufs directly to the 571 * peer socket we have to use SSB_STOP on the sender 572 * to prevent it from building up infinite mbufs. 573 * 574 * As in several places in this module w ehave to ref unp2 575 * to ensure that it does not get ripped out from under us 576 * if we block on the so2 token or in sowwakeup(). 577 */ 578 so2 = unp2->unp_socket; 579 unp_reference(unp2); 580 lwkt_gettoken(&so2->so_rcv.ssb_token); 581 if (so->so_rcv.ssb_cc < so2->so_snd.ssb_hiwat && 582 so->so_rcv.ssb_mbcnt < so2->so_snd.ssb_mbmax 583 ) { 584 atomic_clear_int(&so2->so_snd.ssb_flags, SSB_STOP); 585 586 sowwakeup(so2); 587 } 588 lwkt_reltoken(&so2->so_rcv.ssb_token); 589 unp_free(unp2); 590 break; 591 default: 592 panic("uipc_rcvd unknown socktype"); 593 /*NOTREACHED*/ 594 } 595 error = 0; 596 done: 597 unp_reltoken(unp); 598 lwkt_replymsg(&msg->lmsg, error); 599 } 600 601 /* pru_rcvoob is EOPNOTSUPP */ 602 603 static void 604 uipc_send(netmsg_t msg) 605 { 606 struct unpcb *unp, *unp2; 607 struct socket *so; 608 struct socket *so2; 609 struct mbuf *control; 610 struct mbuf *m; 611 int error = 0; 612 613 so = msg->base.nm_so; 614 control = msg->send.nm_control; 615 m = msg->send.nm_m; 616 617 /* 618 * so_pcb is only modified with both the global and the unp 619 * pool token held. 620 */ 621 so = msg->base.nm_so; 622 unp = unp_getsocktoken(so); 623 624 if (!UNP_ISATTACHED(unp)) { 625 error = EINVAL; 626 goto release; 627 } 628 629 if (msg->send.nm_flags & PRUS_OOB) { 630 error = EOPNOTSUPP; 631 goto release; 632 } 633 634 wakeup_start_delayed(); 635 636 if (control && (error = unp_internalize(control, msg->send.nm_td))) 637 goto release; 638 639 switch (so->so_type) { 640 case SOCK_DGRAM: 641 { 642 struct sockaddr *from; 643 644 if (msg->send.nm_addr) { 645 if (unp->unp_conn) { 646 error = EISCONN; 647 break; 648 } 649 lwkt_gettoken(&unp_token); 650 error = unp_find_lockref(msg->send.nm_addr, 651 msg->send.nm_td, so->so_type, &unp2); 652 if (error) { 653 lwkt_reltoken(&unp_token); 654 break; 655 } 656 /* 657 * NOTE: 658 * unp2 is locked and referenced. 659 * 660 * We could unlock unp2 now, since it was checked 661 * and referenced. 662 */ 663 unp_reltoken(unp2); 664 lwkt_reltoken(&unp_token); 665 } else { 666 if (unp->unp_conn == NULL) { 667 error = ENOTCONN; 668 break; 669 } 670 unp2 = unp->unp_conn; 671 unp_reference(unp2); 672 } 673 /* NOTE: unp2 is referenced. */ 674 so2 = unp2->unp_socket; 675 676 if (unp->unp_addr) 677 from = (struct sockaddr *)unp->unp_addr; 678 else 679 from = &sun_noname; 680 681 lwkt_gettoken(&so2->so_rcv.ssb_token); 682 if (ssb_appendaddr(&so2->so_rcv, from, m, control)) { 683 sorwakeup(so2); 684 m = NULL; 685 control = NULL; 686 } else { 687 error = ENOBUFS; 688 } 689 lwkt_reltoken(&so2->so_rcv.ssb_token); 690 691 unp_free(unp2); 692 break; 693 } 694 695 case SOCK_STREAM: 696 case SOCK_SEQPACKET: 697 /* Connect if not connected yet. */ 698 /* 699 * Note: A better implementation would complain 700 * if not equal to the peer's address. 701 */ 702 if (unp->unp_conn == NULL) { 703 if (msg->send.nm_addr) { 704 error = unp_connect(so, 705 msg->send.nm_addr, 706 msg->send.nm_td); 707 if (error) 708 break; /* XXX */ 709 } 710 /* 711 * NOTE: 712 * unp_conn still could be NULL, even if the 713 * above unp_connect() succeeds; since the 714 * current unp's token could be released due 715 * to blocking operations after unp_conn is 716 * assigned. 717 */ 718 if (unp->unp_conn == NULL) { 719 error = ENOTCONN; 720 break; 721 } 722 } 723 if (so->so_state & SS_CANTSENDMORE) { 724 error = EPIPE; 725 break; 726 } 727 728 unp2 = unp->unp_conn; 729 KASSERT(unp2 != NULL, ("unp is not connected")); 730 so2 = unp2->unp_socket; 731 732 unp_reference(unp2); 733 734 /* 735 * Send to paired receive port, and then reduce 736 * send buffer hiwater marks to maintain backpressure. 737 * Wake up readers. 738 */ 739 lwkt_gettoken(&so2->so_rcv.ssb_token); 740 if (control) { 741 if (ssb_appendcontrol(&so2->so_rcv, m, control)) { 742 control = NULL; 743 m = NULL; 744 } 745 } else if (so->so_type == SOCK_SEQPACKET) { 746 sbappendrecord(&so2->so_rcv.sb, m); 747 m = NULL; 748 } else { 749 sbappend(&so2->so_rcv.sb, m); 750 m = NULL; 751 } 752 753 /* 754 * Because we are transfering mbufs directly to the 755 * peer socket we have to use SSB_STOP on the sender 756 * to prevent it from building up infinite mbufs. 757 */ 758 if (so2->so_rcv.ssb_cc >= so->so_snd.ssb_hiwat || 759 so2->so_rcv.ssb_mbcnt >= so->so_snd.ssb_mbmax 760 ) { 761 atomic_set_int(&so->so_snd.ssb_flags, SSB_STOP); 762 } 763 lwkt_reltoken(&so2->so_rcv.ssb_token); 764 sorwakeup(so2); 765 766 unp_free(unp2); 767 break; 768 769 default: 770 panic("uipc_send unknown socktype"); 771 } 772 773 /* 774 * SEND_EOF is equivalent to a SEND followed by a SHUTDOWN. 775 */ 776 if (msg->send.nm_flags & PRUS_EOF) { 777 socantsendmore(so); 778 unp_shutdown(unp); 779 } 780 781 if (control && error != 0) 782 unp_dispose(control); 783 release: 784 unp_reltoken(unp); 785 wakeup_end_delayed(); 786 787 if (control) 788 m_freem(control); 789 if (m) 790 m_freem(m); 791 lwkt_replymsg(&msg->lmsg, error); 792 } 793 794 /* 795 * MPSAFE 796 */ 797 static void 798 uipc_sense(netmsg_t msg) 799 { 800 struct unpcb *unp; 801 struct socket *so; 802 struct stat *sb; 803 int error; 804 805 so = msg->base.nm_so; 806 sb = msg->sense.nm_stat; 807 808 /* 809 * so_pcb is only modified with both the global and the unp 810 * pool token held. 811 */ 812 unp = unp_getsocktoken(so); 813 814 if (!UNP_ISATTACHED(unp)) { 815 error = EINVAL; 816 goto done; 817 } 818 819 sb->st_blksize = so->so_snd.ssb_hiwat; 820 sb->st_dev = NOUDEV; 821 if (unp->unp_ino == 0) { /* make up a non-zero inode number */ 822 unp->unp_ino = atomic_fetchadd_long(&unp_ino, 1); 823 if (__predict_false(unp->unp_ino == 0)) 824 unp->unp_ino = atomic_fetchadd_long(&unp_ino, 1); 825 } 826 sb->st_ino = unp->unp_ino; 827 error = 0; 828 done: 829 unp_reltoken(unp); 830 lwkt_replymsg(&msg->lmsg, error); 831 } 832 833 static void 834 uipc_shutdown(netmsg_t msg) 835 { 836 struct socket *so; 837 struct unpcb *unp; 838 int error; 839 840 /* 841 * so_pcb is only modified with both the global and the unp 842 * pool token held. 843 */ 844 so = msg->base.nm_so; 845 unp = unp_getsocktoken(so); 846 847 if (UNP_ISATTACHED(unp)) { 848 socantsendmore(so); 849 unp_shutdown(unp); 850 error = 0; 851 } else { 852 error = EINVAL; 853 } 854 855 unp_reltoken(unp); 856 lwkt_replymsg(&msg->lmsg, error); 857 } 858 859 static void 860 uipc_sockaddr(netmsg_t msg) 861 { 862 struct unpcb *unp; 863 int error; 864 865 /* 866 * so_pcb is only modified with both the global and the unp 867 * pool token held. 868 */ 869 unp = unp_getsocktoken(msg->base.nm_so); 870 871 if (UNP_ISATTACHED(unp)) { 872 if (unp->unp_addr) { 873 *msg->sockaddr.nm_nam = 874 dup_sockaddr((struct sockaddr *)unp->unp_addr); 875 } 876 error = 0; 877 } else { 878 error = EINVAL; 879 } 880 881 unp_reltoken(unp); 882 lwkt_replymsg(&msg->lmsg, error); 883 } 884 885 struct pr_usrreqs uipc_usrreqs = { 886 .pru_abort = uipc_abort, 887 .pru_accept = uipc_accept, 888 .pru_attach = uipc_attach, 889 .pru_bind = uipc_bind, 890 .pru_connect = uipc_connect, 891 .pru_connect2 = uipc_connect2, 892 .pru_control = pr_generic_notsupp, 893 .pru_detach = uipc_detach, 894 .pru_disconnect = uipc_disconnect, 895 .pru_listen = uipc_listen, 896 .pru_peeraddr = uipc_peeraddr, 897 .pru_rcvd = uipc_rcvd, 898 .pru_rcvoob = pr_generic_notsupp, 899 .pru_send = uipc_send, 900 .pru_sense = uipc_sense, 901 .pru_shutdown = uipc_shutdown, 902 .pru_sockaddr = uipc_sockaddr, 903 .pru_sosend = sosend, 904 .pru_soreceive = soreceive 905 }; 906 907 void 908 uipc_ctloutput(netmsg_t msg) 909 { 910 struct socket *so; 911 struct sockopt *sopt; 912 struct unpcb *unp; 913 int error = 0; 914 915 so = msg->base.nm_so; 916 sopt = msg->ctloutput.nm_sopt; 917 918 lwkt_gettoken(&unp_token); 919 unp = unp_getsocktoken(so); 920 921 if (!UNP_ISATTACHED(unp)) { 922 error = EINVAL; 923 goto done; 924 } 925 926 switch (sopt->sopt_dir) { 927 case SOPT_GET: 928 switch (sopt->sopt_name) { 929 case LOCAL_PEERCRED: 930 if (unp->unp_flags & UNP_HAVEPC) 931 soopt_from_kbuf(sopt, &unp->unp_peercred, 932 sizeof(unp->unp_peercred)); 933 else { 934 if (so->so_type == SOCK_STREAM) 935 error = ENOTCONN; 936 else if (so->so_type == SOCK_SEQPACKET) 937 error = ENOTCONN; 938 else 939 error = EINVAL; 940 } 941 break; 942 default: 943 error = EOPNOTSUPP; 944 break; 945 } 946 break; 947 case SOPT_SET: 948 default: 949 error = EOPNOTSUPP; 950 break; 951 } 952 953 done: 954 unp_reltoken(unp); 955 lwkt_reltoken(&unp_token); 956 957 lwkt_replymsg(&msg->lmsg, error); 958 } 959 960 /* 961 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 962 * for stream sockets, although the total for sender and receiver is 963 * actually only PIPSIZ. 964 * 965 * Datagram sockets really use the sendspace as the maximum datagram size, 966 * and don't really want to reserve the sendspace. Their recvspace should 967 * be large enough for at least one max-size datagram plus address. 968 * 969 * We want the local send/recv space to be significant larger then lo0's 970 * mtu of 16384. 971 */ 972 #ifndef PIPSIZ 973 #define PIPSIZ 57344 974 #endif 975 static u_long unpst_sendspace = PIPSIZ; 976 static u_long unpst_recvspace = PIPSIZ; 977 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 978 static u_long unpdg_recvspace = 4*1024; 979 980 SYSCTL_DECL(_net_local_seqpacket); 981 SYSCTL_DECL(_net_local_stream); 982 SYSCTL_INT(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 983 &unpst_sendspace, 0, "Size of stream socket send buffer"); 984 SYSCTL_INT(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 985 &unpst_recvspace, 0, "Size of stream socket receive buffer"); 986 987 SYSCTL_DECL(_net_local_dgram); 988 SYSCTL_INT(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 989 &unpdg_sendspace, 0, "Max datagram socket size"); 990 SYSCTL_INT(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 991 &unpdg_recvspace, 0, "Size of datagram socket receive buffer"); 992 993 static int 994 unp_attach(struct socket *so, struct pru_attach_info *ai) 995 { 996 struct unp_global_head *head; 997 struct unpcb *unp; 998 int error; 999 1000 lwkt_gettoken(&unp_token); 1001 1002 if (so->so_snd.ssb_hiwat == 0 || so->so_rcv.ssb_hiwat == 0) { 1003 switch (so->so_type) { 1004 case SOCK_STREAM: 1005 case SOCK_SEQPACKET: 1006 error = soreserve(so, unpst_sendspace, unpst_recvspace, 1007 ai->sb_rlimit); 1008 break; 1009 1010 case SOCK_DGRAM: 1011 error = soreserve(so, unpdg_sendspace, unpdg_recvspace, 1012 ai->sb_rlimit); 1013 break; 1014 1015 default: 1016 panic("unp_attach"); 1017 } 1018 if (error) 1019 goto failed; 1020 } 1021 1022 /* 1023 * In order to support sendfile we have to set either SSB_STOPSUPP 1024 * or SSB_PREALLOC. Unix domain sockets use the SSB_STOP flow 1025 * control mechanism. 1026 */ 1027 if (so->so_type == SOCK_STREAM) { 1028 atomic_set_int(&so->so_rcv.ssb_flags, SSB_STOPSUPP); 1029 atomic_set_int(&so->so_snd.ssb_flags, SSB_STOPSUPP); 1030 } 1031 1032 unp = kmalloc(sizeof(*unp), M_UNPCB, M_WAITOK | M_ZERO | M_NULLOK); 1033 if (unp == NULL) { 1034 error = ENOBUFS; 1035 goto failed; 1036 } 1037 unp->unp_refcnt = 1; 1038 unp->unp_gencnt = ++unp_gencnt; 1039 LIST_INIT(&unp->unp_refs); 1040 unp->unp_socket = so; 1041 unp->unp_rvnode = ai->fd_rdir; /* jail cruft XXX JH */ 1042 so->so_pcb = (caddr_t)unp; 1043 soreference(so); 1044 1045 head = unp_globalhead(so->so_type); 1046 TAILQ_INSERT_TAIL(&head->list, unp, unp_link); 1047 head->count++; 1048 error = 0; 1049 failed: 1050 lwkt_reltoken(&unp_token); 1051 return error; 1052 } 1053 1054 static void 1055 unp_detach(struct unpcb *unp) 1056 { 1057 struct socket *so; 1058 1059 lwkt_gettoken(&unp_token); 1060 lwkt_getpooltoken(unp); 1061 1062 so = unp->unp_socket; 1063 1064 unp->unp_gencnt = ++unp_gencnt; 1065 if (unp->unp_vnode) { 1066 unp->unp_vnode->v_socket = NULL; 1067 vrele(unp->unp_vnode); 1068 unp->unp_vnode = NULL; 1069 } 1070 soisdisconnected(so); 1071 KKASSERT(so->so_pcb == unp); 1072 so->so_pcb = NULL; /* both tokens required */ 1073 unp->unp_socket = NULL; 1074 1075 lwkt_relpooltoken(unp); 1076 lwkt_reltoken(&unp_token); 1077 1078 sofree(so); 1079 1080 KASSERT(unp->unp_conn == NULL, ("unp is still connected")); 1081 KASSERT(LIST_EMPTY(&unp->unp_refs), ("unp still has references")); 1082 1083 if (unp->unp_addr) 1084 kfree(unp->unp_addr, M_SONAME); 1085 kfree(unp, M_UNPCB); 1086 1087 if (unp_rights) 1088 taskqueue_enqueue(unp_taskqueue, &unp_gc_task); 1089 } 1090 1091 static int 1092 unp_bind(struct unpcb *unp, struct sockaddr *nam, struct thread *td) 1093 { 1094 struct proc *p = td->td_proc; 1095 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 1096 struct vnode *vp; 1097 struct vattr vattr; 1098 int error, namelen; 1099 struct nlookupdata nd; 1100 char buf[SOCK_MAXADDRLEN]; 1101 1102 ASSERT_LWKT_TOKEN_HELD(&unp_token); 1103 UNP_ASSERT_TOKEN_HELD(unp); 1104 1105 if (unp->unp_vnode != NULL) 1106 return EINVAL; 1107 1108 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 1109 if (namelen <= 0) 1110 return EINVAL; 1111 strncpy(buf, soun->sun_path, namelen); 1112 buf[namelen] = 0; /* null-terminate the string */ 1113 error = nlookup_init(&nd, buf, UIO_SYSSPACE, 1114 NLC_LOCKVP | NLC_CREATE | NLC_REFDVP); 1115 if (error == 0) 1116 error = nlookup(&nd); 1117 if (error == 0 && nd.nl_nch.ncp->nc_vp != NULL) 1118 error = EADDRINUSE; 1119 if (error) 1120 goto done; 1121 1122 VATTR_NULL(&vattr); 1123 vattr.va_type = VSOCK; 1124 vattr.va_mode = (ACCESSPERMS & ~p->p_fd->fd_cmask); 1125 error = VOP_NCREATE(&nd.nl_nch, nd.nl_dvp, &vp, nd.nl_cred, &vattr); 1126 if (error == 0) { 1127 if (unp->unp_vnode == NULL) { 1128 vp->v_socket = unp->unp_socket; 1129 unp->unp_vnode = vp; 1130 unp->unp_addr = (struct sockaddr_un *)dup_sockaddr(nam); 1131 vn_unlock(vp); 1132 } else { 1133 vput(vp); /* late race */ 1134 error = EINVAL; 1135 } 1136 } 1137 done: 1138 nlookup_done(&nd); 1139 return (error); 1140 } 1141 1142 static int 1143 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1144 { 1145 struct unpcb *unp, *unp2; 1146 int error, flags = 0; 1147 1148 lwkt_gettoken(&unp_token); 1149 1150 unp = unp_getsocktoken(so); 1151 if (!UNP_ISATTACHED(unp)) { 1152 error = EINVAL; 1153 goto failed; 1154 } 1155 1156 if ((unp->unp_flags & UNP_CONNECTING) || unp->unp_conn != NULL) { 1157 error = EISCONN; 1158 goto failed; 1159 } 1160 1161 flags = UNP_CONNECTING; 1162 unp_setflags(unp, flags); 1163 1164 error = unp_find_lockref(nam, td, so->so_type, &unp2); 1165 if (error) 1166 goto failed; 1167 /* 1168 * NOTE: 1169 * unp2 is locked and referenced. 1170 */ 1171 1172 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1173 struct socket *so2, *so3; 1174 struct unpcb *unp3; 1175 1176 so2 = unp2->unp_socket; 1177 if (!(so2->so_options & SO_ACCEPTCONN) || 1178 /* listen is not completed yet */ 1179 !(unp2->unp_flags & UNP_HAVEPCCACHED) || 1180 (so3 = sonewconn_faddr(so2, 0, NULL, 1181 TRUE /* keep ref */)) == NULL) { 1182 error = ECONNREFUSED; 1183 goto done; 1184 } 1185 /* so3 has a socket reference. */ 1186 1187 unp3 = unp_getsocktoken(so3); 1188 if (!UNP_ISATTACHED(unp3)) { 1189 unp_reltoken(unp3); 1190 /* 1191 * Already aborted; we only need to drop the 1192 * socket reference held by sonewconn_faddr(). 1193 */ 1194 sofree(so3); 1195 error = ECONNREFUSED; 1196 goto done; 1197 } 1198 unp_reference(unp3); 1199 /* 1200 * NOTE: 1201 * unp3 is locked and referenced. 1202 */ 1203 1204 /* 1205 * Release so3 socket reference held by sonewconn_faddr(). 1206 * Since we have referenced unp3, neither unp3 nor so3 will 1207 * be destroyed here. 1208 */ 1209 sofree(so3); 1210 1211 if (unp2->unp_addr != NULL) { 1212 unp3->unp_addr = (struct sockaddr_un *) 1213 dup_sockaddr((struct sockaddr *)unp2->unp_addr); 1214 } 1215 1216 /* 1217 * unp_peercred management: 1218 * 1219 * The connecter's (client's) credentials are copied 1220 * from its process structure at the time of connect() 1221 * (which is now). 1222 */ 1223 cru2x(td->td_proc->p_ucred, &unp3->unp_peercred); 1224 unp_setflags(unp3, UNP_HAVEPC); 1225 /* 1226 * The receiver's (server's) credentials are copied 1227 * from the unp_peercred member of socket on which the 1228 * former called listen(); unp_listen() cached that 1229 * process's credentials at that time so we can use 1230 * them now. 1231 */ 1232 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1233 ("unp_connect: listener without cached peercred")); 1234 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1235 sizeof(unp->unp_peercred)); 1236 unp_setflags(unp, UNP_HAVEPC); 1237 1238 error = unp_connect_pair(unp, unp3); 1239 if (error) 1240 soabort_direct(so3); 1241 1242 /* Done with unp3 */ 1243 unp_free(unp3); 1244 unp_reltoken(unp3); 1245 } else { 1246 error = unp_connect_pair(unp, unp2); 1247 } 1248 done: 1249 unp_free(unp2); 1250 unp_reltoken(unp2); 1251 failed: 1252 if (flags) 1253 unp_clrflags(unp, flags); 1254 unp_reltoken(unp); 1255 1256 lwkt_reltoken(&unp_token); 1257 return (error); 1258 } 1259 1260 /* 1261 * Connect two unix domain sockets together. 1262 * 1263 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1264 * pool token also be held. 1265 */ 1266 int 1267 unp_connect2(struct socket *so, struct socket *so2) 1268 { 1269 struct unpcb *unp, *unp2; 1270 int error; 1271 1272 lwkt_gettoken(&unp_token); 1273 if (so2->so_type != so->so_type) { 1274 lwkt_reltoken(&unp_token); 1275 return (EPROTOTYPE); 1276 } 1277 unp = unp_getsocktoken(so); 1278 unp2 = unp_getsocktoken(so2); 1279 1280 if (!UNP_ISATTACHED(unp)) { 1281 error = EINVAL; 1282 goto done; 1283 } 1284 if (!UNP_ISATTACHED(unp2)) { 1285 error = ECONNREFUSED; 1286 goto done; 1287 } 1288 1289 if (unp->unp_conn != NULL) { 1290 error = EISCONN; 1291 goto done; 1292 } 1293 if ((so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET) && 1294 unp2->unp_conn != NULL) { 1295 error = EISCONN; 1296 goto done; 1297 } 1298 1299 error = unp_connect_pair(unp, unp2); 1300 done: 1301 unp_reltoken(unp2); 1302 unp_reltoken(unp); 1303 lwkt_reltoken(&unp_token); 1304 return (error); 1305 } 1306 1307 /* 1308 * Disconnect a unix domain socket pair. 1309 * 1310 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1311 * pool token also be held. 1312 */ 1313 static void 1314 unp_disconnect(struct unpcb *unp, int error) 1315 { 1316 struct socket *so = unp->unp_socket; 1317 struct unpcb *unp2; 1318 1319 ASSERT_LWKT_TOKEN_HELD(&unp_token); 1320 UNP_ASSERT_TOKEN_HELD(unp); 1321 1322 if (error) 1323 so->so_error = error; 1324 1325 while ((unp2 = unp->unp_conn) != NULL) { 1326 lwkt_getpooltoken(unp2); 1327 if (unp2 == unp->unp_conn) 1328 break; 1329 lwkt_relpooltoken(unp2); 1330 } 1331 if (unp2 == NULL) 1332 return; 1333 /* unp2 is locked. */ 1334 1335 KASSERT((unp2->unp_flags & UNP_DROPPED) == 0, ("unp2 was dropped")); 1336 1337 unp->unp_conn = NULL; 1338 1339 switch (so->so_type) { 1340 case SOCK_DGRAM: 1341 LIST_REMOVE(unp, unp_reflink); 1342 soclrstate(so, SS_ISCONNECTED); 1343 break; 1344 1345 case SOCK_STREAM: 1346 case SOCK_SEQPACKET: 1347 /* 1348 * Keep a reference before clearing the unp_conn 1349 * to avoid racing uipc_detach()/uipc_abort() in 1350 * other thread. 1351 */ 1352 unp_reference(unp2); 1353 KASSERT(unp2->unp_conn == unp, ("unp_conn mismatch")); 1354 unp2->unp_conn = NULL; 1355 1356 soisdisconnected(so); 1357 soisdisconnected(unp2->unp_socket); 1358 1359 unp_free(unp2); 1360 break; 1361 } 1362 1363 lwkt_relpooltoken(unp2); 1364 } 1365 1366 #ifdef notdef 1367 void 1368 unp_abort(struct unpcb *unp) 1369 { 1370 lwkt_gettoken(&unp_token); 1371 unp_free(unp); 1372 lwkt_reltoken(&unp_token); 1373 } 1374 #endif 1375 1376 static int 1377 prison_unpcb(struct thread *td, struct unpcb *unp) 1378 { 1379 struct proc *p; 1380 1381 if (td == NULL) 1382 return (0); 1383 if ((p = td->td_proc) == NULL) 1384 return (0); 1385 if (!p->p_ucred->cr_prison) 1386 return (0); 1387 if (p->p_fd->fd_rdir == unp->unp_rvnode) 1388 return (0); 1389 return (1); 1390 } 1391 1392 static int 1393 unp_pcblist(SYSCTL_HANDLER_ARGS) 1394 { 1395 struct unp_global_head *head = arg1; 1396 int error, i, n; 1397 struct unpcb *unp, *marker; 1398 1399 KKASSERT(curproc != NULL); 1400 1401 /* 1402 * The process of preparing the PCB list is too time-consuming and 1403 * resource-intensive to repeat twice on every request. 1404 */ 1405 if (req->oldptr == NULL) { 1406 n = head->count; 1407 req->oldidx = (n + n/8) * sizeof(struct xunpcb); 1408 return 0; 1409 } 1410 1411 if (req->newptr != NULL) 1412 return EPERM; 1413 1414 marker = kmalloc(sizeof(*marker), M_UNPCB, M_WAITOK | M_ZERO); 1415 marker->unp_flags |= UNP_MARKER; 1416 1417 lwkt_gettoken(&unp_token); 1418 1419 n = head->count; 1420 i = 0; 1421 error = 0; 1422 1423 TAILQ_INSERT_HEAD(&head->list, marker, unp_link); 1424 while ((unp = TAILQ_NEXT(marker, unp_link)) != NULL && i < n) { 1425 struct xunpcb xu; 1426 1427 TAILQ_REMOVE(&head->list, marker, unp_link); 1428 TAILQ_INSERT_AFTER(&head->list, unp, marker, unp_link); 1429 1430 if (unp->unp_flags & UNP_MARKER) 1431 continue; 1432 if (prison_unpcb(req->td, unp)) 1433 continue; 1434 1435 xu.xu_len = sizeof(xu); 1436 xu.xu_unpp = unp; 1437 1438 /* 1439 * NOTE: 1440 * unp->unp_addr and unp->unp_conn are protected by 1441 * unp_token. So if we want to get rid of unp_token 1442 * or reduce the coverage of unp_token, care must be 1443 * taken. 1444 */ 1445 if (unp->unp_addr) { 1446 bcopy(unp->unp_addr, &xu.xu_addr, 1447 unp->unp_addr->sun_len); 1448 } 1449 if (unp->unp_conn && unp->unp_conn->unp_addr) { 1450 bcopy(unp->unp_conn->unp_addr, 1451 &xu.xu_caddr, 1452 unp->unp_conn->unp_addr->sun_len); 1453 } 1454 bcopy(unp, &xu.xu_unp, sizeof(*unp)); 1455 sotoxsocket(unp->unp_socket, &xu.xu_socket); 1456 1457 /* NOTE: This could block and temporarily release unp_token */ 1458 error = SYSCTL_OUT(req, &xu, sizeof(xu)); 1459 if (error) 1460 break; 1461 ++i; 1462 } 1463 TAILQ_REMOVE(&head->list, marker, unp_link); 1464 1465 lwkt_reltoken(&unp_token); 1466 1467 kfree(marker, M_UNPCB); 1468 return error; 1469 } 1470 1471 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1472 &unp_dgram_head, 0, unp_pcblist, "S,xunpcb", 1473 "List of active local datagram sockets"); 1474 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1475 &unp_stream_head, 0, unp_pcblist, "S,xunpcb", 1476 "List of active local stream sockets"); 1477 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist, CTLFLAG_RD, 1478 &unp_seqpkt_head, 0, unp_pcblist, "S,xunpcb", 1479 "List of active local seqpacket sockets"); 1480 1481 static void 1482 unp_shutdown(struct unpcb *unp) 1483 { 1484 struct socket *so; 1485 1486 if ((unp->unp_socket->so_type == SOCK_STREAM || 1487 unp->unp_socket->so_type == SOCK_SEQPACKET) && 1488 unp->unp_conn != NULL && (so = unp->unp_conn->unp_socket)) { 1489 socantrcvmore(so); 1490 } 1491 } 1492 1493 #ifdef notdef 1494 void 1495 unp_drain(void) 1496 { 1497 lwkt_gettoken(&unp_token); 1498 lwkt_reltoken(&unp_token); 1499 } 1500 #endif 1501 1502 int 1503 unp_externalize(struct mbuf *rights, int flags) 1504 { 1505 struct thread *td = curthread; 1506 struct proc *p = td->td_proc; /* XXX */ 1507 struct lwp *lp = td->td_lwp; 1508 struct cmsghdr *cm = mtod(rights, struct cmsghdr *); 1509 int *fdp; 1510 int i; 1511 struct file **rp; 1512 struct file *fp; 1513 int newfds = (cm->cmsg_len - (CMSG_DATA(cm) - (u_char *)cm)) 1514 / sizeof(struct file *); 1515 int f; 1516 1517 lwkt_gettoken(&unp_rights_token); 1518 1519 /* 1520 * if the new FD's will not fit, then we free them all 1521 */ 1522 if (!fdavail(p, newfds)) { 1523 rp = (struct file **)CMSG_DATA(cm); 1524 for (i = 0; i < newfds; i++) { 1525 fp = *rp; 1526 /* 1527 * zero the pointer before calling unp_discard, 1528 * since it may end up in unp_gc().. 1529 */ 1530 *rp++ = NULL; 1531 unp_discard(fp, NULL); 1532 } 1533 lwkt_reltoken(&unp_rights_token); 1534 return (EMSGSIZE); 1535 } 1536 1537 /* 1538 * now change each pointer to an fd in the global table to 1539 * an integer that is the index to the local fd table entry 1540 * that we set up to point to the global one we are transferring. 1541 * Since the sizeof(struct file *) is bigger than or equal to 1542 * the sizeof(int), we do it in forward order. In that case, 1543 * an integer will always come in the same place or before its 1544 * corresponding struct file pointer. 1545 * 1546 * Hold revoke_token in 'shared' mode, so that we won't miss 1547 * the FREVOKED update on fps being externalized (fsetfd). 1548 */ 1549 lwkt_gettoken_shared(&revoke_token); 1550 fdp = (int *)CMSG_DATA(cm); 1551 rp = (struct file **)CMSG_DATA(cm); 1552 for (i = 0; i < newfds; i++) { 1553 if (fdalloc(p, 0, &f)) { 1554 int j; 1555 1556 /* 1557 * Previous fdavail() can't garantee 1558 * fdalloc() success due to SMP race. 1559 * Just clean up and return the same 1560 * error value as if fdavail() failed. 1561 */ 1562 lwkt_reltoken(&revoke_token); 1563 1564 /* Close externalized files */ 1565 for (j = 0; j < i; j++) 1566 kern_close(fdp[j]); 1567 /* Discard the rest of internal files */ 1568 for (; i < newfds; i++) 1569 unp_discard(rp[i], NULL); 1570 /* Wipe out the control message */ 1571 for (i = 0; i < newfds; i++) 1572 rp[i] = NULL; 1573 1574 lwkt_reltoken(&unp_rights_token); 1575 return (EMSGSIZE); 1576 } 1577 fp = rp[i]; 1578 unp_fp_externalize(lp, fp, f, flags); 1579 fdp[i] = f; 1580 } 1581 lwkt_reltoken(&revoke_token); 1582 1583 lwkt_reltoken(&unp_rights_token); 1584 1585 /* 1586 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1587 * differs. 1588 */ 1589 cm->cmsg_len = CMSG_LEN(newfds * sizeof(int)); 1590 rights->m_len = cm->cmsg_len; 1591 1592 return (0); 1593 } 1594 1595 static void 1596 unp_fp_externalize(struct lwp *lp, struct file *fp, int fd, int flags) 1597 { 1598 if (lp) { 1599 struct filedesc *fdp = lp->lwp_proc->p_fd; 1600 1601 KKASSERT(fd >= 0); 1602 if (fp->f_flag & FREVOKED) { 1603 struct file *fx; 1604 int error; 1605 1606 kprintf("Warning: revoked fp exiting unix socket\n"); 1607 error = falloc(lp, &fx, NULL); 1608 if (error == 0) { 1609 if (flags & MSG_CMSG_CLOEXEC) 1610 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1611 fsetfd(fdp, fx, fd); 1612 fdrop(fx); 1613 } else { 1614 fsetfd(fdp, NULL, fd); 1615 } 1616 } else { 1617 if (flags & MSG_CMSG_CLOEXEC) 1618 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1619 fsetfd(fdp, fp, fd); 1620 } 1621 } 1622 unp_del_right(fp); 1623 fdrop(fp); 1624 } 1625 1626 void 1627 unp_init(void) 1628 { 1629 TAILQ_INIT(&unp_stream_head.list); 1630 TAILQ_INIT(&unp_dgram_head.list); 1631 TAILQ_INIT(&unp_seqpkt_head.list); 1632 1633 SLIST_INIT(&unp_defdiscard_head); 1634 spin_init(&unp_defdiscard_spin, "unpdisc"); 1635 TASK_INIT(&unp_defdiscard_task, 0, unp_defdiscard_taskfunc, NULL); 1636 1637 /* 1638 * This implies that only one gc can be in-progress at any 1639 * given moment. 1640 */ 1641 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1642 1643 unp_gc_marker = kmalloc(sizeof(*unp_gc_marker), M_UNPCB, 1644 M_WAITOK | M_ZERO); 1645 unp_gc_marker->unp_flags |= UNP_MARKER; 1646 1647 /* 1648 * Create taskqueue for defered discard, and stick it to 1649 * the last CPU. 1650 */ 1651 unp_taskqueue = taskqueue_create("unp_taskq", M_WAITOK, 1652 taskqueue_thread_enqueue, &unp_taskqueue); 1653 taskqueue_start_threads(&unp_taskqueue, 1, TDPRI_KERN_DAEMON, 1654 ncpus - 1, "unp taskq"); 1655 } 1656 1657 static int 1658 unp_internalize(struct mbuf *control, struct thread *td) 1659 { 1660 struct proc *p = td->td_proc; 1661 struct filedesc *fdescp; 1662 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1663 struct file **rp; 1664 struct file *fp; 1665 int i, fd, *fdp; 1666 struct cmsgcred *cmcred; 1667 int oldfds; 1668 u_int newlen; 1669 int error; 1670 1671 KKASSERT(p); 1672 1673 if ((cm->cmsg_type != SCM_RIGHTS && cm->cmsg_type != SCM_CREDS) || 1674 cm->cmsg_level != SOL_SOCKET || 1675 CMSG_ALIGN(cm->cmsg_len) != control->m_len) 1676 return EINVAL; 1677 1678 /* 1679 * Fill in credential information. 1680 */ 1681 if (cm->cmsg_type == SCM_CREDS) { 1682 cmcred = (struct cmsgcred *)CMSG_DATA(cm); 1683 cmcred->cmcred_pid = p->p_pid; 1684 cmcred->cmcred_uid = p->p_ucred->cr_ruid; 1685 cmcred->cmcred_gid = p->p_ucred->cr_rgid; 1686 cmcred->cmcred_euid = p->p_ucred->cr_uid; 1687 cmcred->cmcred_ngroups = MIN(p->p_ucred->cr_ngroups, 1688 CMGROUP_MAX); 1689 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1690 cmcred->cmcred_groups[i] = p->p_ucred->cr_groups[i]; 1691 return 0; 1692 } 1693 1694 /* 1695 * cmsghdr may not be aligned, do not allow calculation(s) to 1696 * go negative. 1697 */ 1698 if (cm->cmsg_len < CMSG_LEN(0)) 1699 return EINVAL; 1700 1701 oldfds = (cm->cmsg_len - CMSG_LEN(0)) / sizeof(int); 1702 1703 /* 1704 * Now replace the integer FDs with pointers to 1705 * the associated global file table entry.. 1706 * Allocate a bigger buffer as necessary. But if an cluster is not 1707 * enough, return E2BIG. 1708 */ 1709 newlen = CMSG_LEN(oldfds * sizeof(struct file *)); 1710 if (newlen > MCLBYTES) 1711 return E2BIG; 1712 if (newlen - control->m_len > M_TRAILINGSPACE(control)) { 1713 if (control->m_flags & M_EXT) 1714 return E2BIG; 1715 MCLGET(control, M_WAITOK); 1716 if (!(control->m_flags & M_EXT)) 1717 return ENOBUFS; 1718 1719 /* copy the data to the cluster */ 1720 memcpy(mtod(control, char *), cm, cm->cmsg_len); 1721 cm = mtod(control, struct cmsghdr *); 1722 } 1723 1724 lwkt_gettoken(&unp_rights_token); 1725 1726 fdescp = p->p_fd; 1727 spin_lock_shared(&fdescp->fd_spin); 1728 1729 /* 1730 * check that all the FDs passed in refer to legal OPEN files 1731 * If not, reject the entire operation. 1732 */ 1733 fdp = (int *)CMSG_DATA(cm); 1734 for (i = 0; i < oldfds; i++) { 1735 fd = *fdp++; 1736 if ((unsigned)fd >= fdescp->fd_nfiles || 1737 fdescp->fd_files[fd].fp == NULL) { 1738 error = EBADF; 1739 goto done; 1740 } 1741 if (fdescp->fd_files[fd].fp->f_type == DTYPE_KQUEUE) { 1742 error = EOPNOTSUPP; 1743 goto done; 1744 } 1745 } 1746 1747 /* 1748 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1749 * differs. 1750 */ 1751 cm->cmsg_len = newlen; 1752 control->m_len = CMSG_ALIGN(newlen); 1753 1754 /* 1755 * Transform the file descriptors into struct file pointers. 1756 * Since the sizeof(struct file *) is bigger than or equal to 1757 * the sizeof(int), we do it in reverse order so that the int 1758 * won't get trashed until we're done. 1759 */ 1760 fdp = (int *)CMSG_DATA(cm) + oldfds - 1; 1761 rp = (struct file **)CMSG_DATA(cm) + oldfds - 1; 1762 for (i = 0; i < oldfds; i++) { 1763 fp = fdescp->fd_files[*fdp--].fp; 1764 *rp-- = fp; 1765 fhold(fp); 1766 unp_add_right(fp); 1767 } 1768 error = 0; 1769 done: 1770 spin_unlock_shared(&fdescp->fd_spin); 1771 lwkt_reltoken(&unp_rights_token); 1772 return error; 1773 } 1774 1775 #ifdef UNP_GC_ALLFILES 1776 1777 /* 1778 * Garbage collect in-transit file descriptors that get lost due to 1779 * loops (i.e. when a socket is sent to another process over itself, 1780 * and more complex situations). 1781 * 1782 * NOT MPSAFE - TODO socket flush code and maybe fdrop. Rest is MPSAFE. 1783 */ 1784 1785 struct unp_gc_info { 1786 struct file **extra_ref; 1787 struct file *locked_fp; 1788 int defer; 1789 int index; 1790 int maxindex; 1791 }; 1792 1793 static void 1794 unp_gc(void *arg __unused, int pending __unused) 1795 { 1796 struct unp_gc_info info; 1797 struct file **fpp; 1798 int i; 1799 1800 lwkt_gettoken(&unp_rights_token); 1801 1802 /* 1803 * Before going through all this, set all FDs to be NOT defered 1804 * and NOT externally accessible (not marked). During the scan 1805 * a fd can be marked externally accessible but we may or may not 1806 * be able to immediately process it (controlled by FDEFER). 1807 * 1808 * If we loop sleep a bit. The complexity of the topology can cause 1809 * multiple loops. Also failure to acquire the socket's so_rcv 1810 * token can cause us to loop. 1811 */ 1812 allfiles_scan_exclusive(unp_gc_clearmarks, NULL); 1813 do { 1814 info.defer = 0; 1815 allfiles_scan_exclusive(unp_gc_checkmarks, &info); 1816 if (info.defer) 1817 tsleep(&info, 0, "gcagain", 1); 1818 } while (info.defer); 1819 1820 /* 1821 * We grab an extra reference to each of the file table entries 1822 * that are not otherwise accessible and then free the rights 1823 * that are stored in messages on them. 1824 * 1825 * The bug in the orginal code is a little tricky, so I'll describe 1826 * what's wrong with it here. 1827 * 1828 * It is incorrect to simply unp_discard each entry for f_msgcount 1829 * times -- consider the case of sockets A and B that contain 1830 * references to each other. On a last close of some other socket, 1831 * we trigger a gc since the number of outstanding rights (unp_rights) 1832 * is non-zero. If during the sweep phase the gc code unp_discards, 1833 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 1834 * results in the following chain. Closef calls soo_close, which 1835 * calls soclose. Soclose calls first (through the switch 1836 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1837 * returns because the previous instance had set unp_gcing, and 1838 * we return all the way back to soclose, which marks the socket 1839 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1840 * to free up the rights that are queued in messages on the socket A, 1841 * i.e., the reference on B. The sorflush calls via the dom_dispose 1842 * switch unp_dispose, which unp_scans with unp_discard. This second 1843 * instance of unp_discard just calls fdrop on B. 1844 * 1845 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1846 * which results in another fdrop on A. Unfortunately, A is already 1847 * being closed, and the descriptor has already been marked with 1848 * SS_NOFDREF, and soclose panics at this point. 1849 * 1850 * Here, we first take an extra reference to each inaccessible 1851 * descriptor. Then, we call sorflush ourself, since we know 1852 * it is a Unix domain socket anyhow. After we destroy all the 1853 * rights carried in messages, we do a last fdrop to get rid 1854 * of our extra reference. This is the last close, and the 1855 * unp_detach etc will shut down the socket. 1856 * 1857 * 91/09/19, bsy@cs.cmu.edu 1858 */ 1859 info.extra_ref = kmalloc(256 * sizeof(struct file *), M_FILE, M_WAITOK); 1860 info.maxindex = 256; 1861 1862 do { 1863 /* 1864 * Look for matches 1865 */ 1866 info.index = 0; 1867 allfiles_scan_exclusive(unp_gc_checkrefs, &info); 1868 1869 /* 1870 * For each FD on our hit list, do the following two things 1871 */ 1872 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) { 1873 struct file *tfp = *fpp; 1874 if (tfp->f_type == DTYPE_SOCKET && tfp->f_data != NULL) 1875 sorflush((struct socket *)(tfp->f_data)); 1876 } 1877 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) 1878 fdrop(*fpp); 1879 } while (info.index == info.maxindex); 1880 1881 kfree((caddr_t)info.extra_ref, M_FILE); 1882 1883 lwkt_reltoken(&unp_rights_token); 1884 } 1885 1886 /* 1887 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1888 */ 1889 static int 1890 unp_gc_checkrefs(struct file *fp, void *data) 1891 { 1892 struct unp_gc_info *info = data; 1893 1894 if (fp->f_count == 0) 1895 return(0); 1896 if (info->index == info->maxindex) 1897 return(-1); 1898 1899 /* 1900 * If all refs are from msgs, and it's not marked accessible 1901 * then it must be referenced from some unreachable cycle 1902 * of (shut-down) FDs, so include it in our 1903 * list of FDs to remove 1904 */ 1905 if (fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) { 1906 info->extra_ref[info->index++] = fp; 1907 fhold(fp); 1908 } 1909 return(0); 1910 } 1911 1912 /* 1913 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1914 */ 1915 static int 1916 unp_gc_clearmarks(struct file *fp, void *data __unused) 1917 { 1918 atomic_clear_int(&fp->f_flag, FMARK | FDEFER); 1919 return(0); 1920 } 1921 1922 /* 1923 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1924 */ 1925 static int 1926 unp_gc_checkmarks(struct file *fp, void *data) 1927 { 1928 struct unp_gc_info *info = data; 1929 struct socket *so; 1930 1931 /* 1932 * If the file is not open, skip it. Make sure it isn't marked 1933 * defered or we could loop forever, in case we somehow race 1934 * something. 1935 */ 1936 if (fp->f_count == 0) { 1937 if (fp->f_flag & FDEFER) 1938 atomic_clear_int(&fp->f_flag, FDEFER); 1939 return(0); 1940 } 1941 /* 1942 * If we already marked it as 'defer' in a 1943 * previous pass, then try process it this time 1944 * and un-mark it 1945 */ 1946 if (fp->f_flag & FDEFER) { 1947 atomic_clear_int(&fp->f_flag, FDEFER); 1948 } else { 1949 /* 1950 * if it's not defered, then check if it's 1951 * already marked.. if so skip it 1952 */ 1953 if (fp->f_flag & FMARK) 1954 return(0); 1955 /* 1956 * If all references are from messages 1957 * in transit, then skip it. it's not 1958 * externally accessible. 1959 */ 1960 if (fp->f_count == fp->f_msgcount) 1961 return(0); 1962 /* 1963 * If it got this far then it must be 1964 * externally accessible. 1965 */ 1966 atomic_set_int(&fp->f_flag, FMARK); 1967 } 1968 1969 /* 1970 * either it was defered, or it is externally 1971 * accessible and not already marked so. 1972 * Now check if it is possibly one of OUR sockets. 1973 */ 1974 if (fp->f_type != DTYPE_SOCKET || 1975 (so = (struct socket *)fp->f_data) == NULL) { 1976 return(0); 1977 } 1978 if (so->so_proto->pr_domain != &localdomain || 1979 !(so->so_proto->pr_flags & PR_RIGHTS)) { 1980 return(0); 1981 } 1982 1983 /* 1984 * So, Ok, it's one of our sockets and it IS externally accessible 1985 * (or was defered). Now we look to see if we hold any file 1986 * descriptors in its message buffers. Follow those links and mark 1987 * them as accessible too. 1988 * 1989 * We are holding multiple spinlocks here, if we cannot get the 1990 * token non-blocking defer until the next loop. 1991 */ 1992 info->locked_fp = fp; 1993 if (lwkt_trytoken(&so->so_rcv.ssb_token)) { 1994 unp_scan(so->so_rcv.ssb_mb, unp_mark, info); 1995 lwkt_reltoken(&so->so_rcv.ssb_token); 1996 } else { 1997 atomic_set_int(&fp->f_flag, FDEFER); 1998 ++info->defer; 1999 } 2000 return (0); 2001 } 2002 2003 /* 2004 * Mark visibility. info->defer is recalculated on every pass. 2005 */ 2006 static void 2007 unp_mark(struct file *fp, void *data) 2008 { 2009 struct unp_gc_info *info = data; 2010 2011 if ((fp->f_flag & FMARK) == 0) { 2012 ++info->defer; 2013 atomic_set_int(&fp->f_flag, FMARK | FDEFER); 2014 } else if (fp->f_flag & FDEFER) { 2015 ++info->defer; 2016 } 2017 } 2018 2019 #else /* !UNP_GC_ALLFILES */ 2020 2021 /* 2022 * They are thread local and do not require explicit synchronization. 2023 */ 2024 static int unp_marked; 2025 static int unp_unreachable; 2026 2027 static void 2028 unp_accessable(struct file *fp, void *data __unused) 2029 { 2030 struct unpcb *unp; 2031 2032 if ((unp = unp_fp2unpcb(fp)) == NULL) 2033 return; 2034 if (unp->unp_gcflags & UNPGC_REF) 2035 return; 2036 unp->unp_gcflags &= ~UNPGC_DEAD; 2037 unp->unp_gcflags |= UNPGC_REF; 2038 unp_marked++; 2039 } 2040 2041 static void 2042 unp_gc_process(struct unpcb *unp) 2043 { 2044 struct file *fp; 2045 2046 /* Already processed. */ 2047 if (unp->unp_gcflags & UNPGC_SCANNED) 2048 return; 2049 fp = unp->unp_fp; 2050 2051 /* 2052 * Check for a socket potentially in a cycle. It must be in a 2053 * queue as indicated by msgcount, and this must equal the file 2054 * reference count. Note that when msgcount is 0 the file is NULL. 2055 */ 2056 if ((unp->unp_gcflags & UNPGC_REF) == 0 && fp && 2057 unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) { 2058 unp->unp_gcflags |= UNPGC_DEAD; 2059 unp_unreachable++; 2060 return; 2061 } 2062 2063 /* 2064 * Mark all sockets we reference with RIGHTS. 2065 */ 2066 if (UNP_ISATTACHED(unp)) { 2067 struct signalsockbuf *ssb = &unp->unp_socket->so_rcv; 2068 2069 unp_reference(unp); 2070 lwkt_gettoken(&ssb->ssb_token); 2071 /* 2072 * unp_token would be temporarily dropped, if getting 2073 * so_rcv token blocks, so we need to check unp state 2074 * here again. 2075 */ 2076 if (UNP_ISATTACHED(unp)) 2077 unp_scan(ssb->ssb_mb, unp_accessable, NULL); 2078 lwkt_reltoken(&ssb->ssb_token); 2079 unp->unp_gcflags |= UNPGC_SCANNED; 2080 unp_free(unp); 2081 } else { 2082 unp->unp_gcflags |= UNPGC_SCANNED; 2083 } 2084 } 2085 2086 static void 2087 unp_gc(void *arg __unused, int pending __unused) 2088 { 2089 struct unp_global_head *head; 2090 int h, filemax, fileidx, filetot; 2091 struct file **unref; 2092 struct unpcb *unp; 2093 2094 lwkt_gettoken(&unp_rights_token); 2095 lwkt_gettoken(&unp_token); 2096 2097 /* 2098 * First clear all gc flags from previous runs. 2099 */ 2100 for (h = 0; unp_heads[h] != NULL; ++h) { 2101 /* 2102 * NOTE: This loop does not block, so it is safe 2103 * to use TAILQ_FOREACH here. 2104 */ 2105 head = unp_heads[h]; 2106 TAILQ_FOREACH(unp, &head->list, unp_link) 2107 unp->unp_gcflags = 0; 2108 } 2109 2110 /* 2111 * Scan marking all reachable sockets with UNPGC_REF. Once a socket 2112 * is reachable all of the sockets it references are reachable. 2113 * Stop the scan once we do a complete loop without discovering 2114 * a new reachable socket. 2115 */ 2116 do { 2117 unp_unreachable = 0; 2118 unp_marked = 0; 2119 for (h = 0; unp_heads[h] != NULL; ++h) { 2120 head = unp_heads[h]; 2121 TAILQ_INSERT_HEAD(&head->list, unp_gc_marker, unp_link); 2122 while ((unp = TAILQ_NEXT(unp_gc_marker, unp_link)) 2123 != NULL) { 2124 TAILQ_REMOVE(&head->list, unp_gc_marker, 2125 unp_link); 2126 TAILQ_INSERT_AFTER(&head->list, unp, 2127 unp_gc_marker, unp_link); 2128 2129 if (unp->unp_flags & UNP_MARKER) 2130 continue; 2131 unp_gc_process(unp); 2132 } 2133 TAILQ_REMOVE(&head->list, unp_gc_marker, unp_link); 2134 } 2135 } while (unp_marked); 2136 2137 if (unp_unreachable == 0) 2138 goto done; 2139 2140 /* 2141 * We grab an extra reference to each of the file table entries 2142 * that are not otherwise accessible and then free the rights 2143 * that are stored in messages on them. 2144 * 2145 * The bug in the orginal code is a little tricky, so I'll describe 2146 * what's wrong with it here. 2147 * 2148 * It is incorrect to simply unp_discard each entry for f_msgcount 2149 * times -- consider the case of sockets A and B that contain 2150 * references to each other. On a last close of some other socket, 2151 * we trigger a gc since the number of outstanding rights (unp_rights) 2152 * is non-zero. If during the sweep phase the gc code unp_discards, 2153 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 2154 * results in the following chain. Closef calls soo_close, which 2155 * calls soclose. Soclose calls first (through the switch 2156 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2157 * returns because the previous instance had set unp_gcing, and 2158 * we return all the way back to soclose, which marks the socket 2159 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 2160 * to free up the rights that are queued in messages on the socket A, 2161 * i.e., the reference on B. The sorflush calls via the dom_dispose 2162 * switch unp_dispose, which unp_scans with unp_discard. This second 2163 * instance of unp_discard just calls fdrop on B. 2164 * 2165 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2166 * which results in another fdrop on A. Unfortunately, A is already 2167 * being closed, and the descriptor has already been marked with 2168 * SS_NOFDREF, and soclose panics at this point. 2169 * 2170 * Here, we first take an extra reference to each inaccessible 2171 * descriptor. Then, we call sorflush ourself, since we know 2172 * it is a Unix domain socket anyhow. After we destroy all the 2173 * rights carried in messages, we do a last fdrop to get rid 2174 * of our extra reference. This is the last close, and the 2175 * unp_detach etc will shut down the socket. 2176 * 2177 * 91/09/19, bsy@cs.cmu.edu 2178 */ 2179 2180 filemax = unp_unreachable; 2181 if (filemax > UNP_GCFILE_MAX) 2182 filemax = UNP_GCFILE_MAX; 2183 unref = kmalloc(filemax * sizeof(struct file *), M_TEMP, M_WAITOK); 2184 2185 filetot = 0; 2186 do { 2187 int i; 2188 2189 /* 2190 * Iterate looking for sockets which have been specifically 2191 * marked as as unreachable and store them locally. 2192 */ 2193 fileidx = 0; 2194 for (h = 0; unp_heads[h] != NULL; ++h) { 2195 /* 2196 * NOTE: This loop does not block, so it is safe 2197 * to use TAILQ_FOREACH here. 2198 */ 2199 head = unp_heads[h]; 2200 TAILQ_FOREACH(unp, &head->list, unp_link) { 2201 struct file *fp; 2202 2203 if ((unp->unp_gcflags & UNPGC_DEAD) == 0) 2204 continue; 2205 unp->unp_gcflags &= ~UNPGC_DEAD; 2206 2207 fp = unp->unp_fp; 2208 if (unp->unp_msgcount == 0 || fp == NULL || 2209 fp->f_count != unp->unp_msgcount) 2210 continue; 2211 fhold(fp); 2212 2213 KASSERT(fileidx < filemax, 2214 ("invalid fileidx %d, filemax %d", 2215 fileidx, filemax)); 2216 unref[fileidx++] = fp; 2217 2218 KASSERT(filetot < unp_unreachable, 2219 ("invalid filetot %d and " 2220 "unp_unreachable %d", 2221 filetot, unp_unreachable)); 2222 ++filetot; 2223 2224 if (fileidx == filemax || 2225 filetot == unp_unreachable) 2226 goto dogc; 2227 } 2228 } 2229 dogc: 2230 /* 2231 * For each Unix domain socket on our hit list, do the 2232 * following two things. 2233 */ 2234 for (i = 0; i < fileidx; ++i) 2235 sorflush(unref[i]->f_data); 2236 for (i = 0; i < fileidx; ++i) 2237 fdrop(unref[i]); 2238 } while (fileidx == filemax && filetot < unp_unreachable); 2239 kfree(unref, M_TEMP); 2240 done: 2241 lwkt_reltoken(&unp_token); 2242 lwkt_reltoken(&unp_rights_token); 2243 } 2244 2245 #endif /* UNP_GC_ALLFILES */ 2246 2247 /* 2248 * Dispose of the fp's stored in a mbuf. 2249 * 2250 * The dds loop can cause additional fps to be entered onto the 2251 * list while it is running, flattening out the operation and avoiding 2252 * a deep kernel stack recursion. 2253 */ 2254 void 2255 unp_dispose(struct mbuf *m) 2256 { 2257 lwkt_gettoken(&unp_rights_token); 2258 if (m) 2259 unp_scan(m, unp_discard, NULL); 2260 lwkt_reltoken(&unp_rights_token); 2261 } 2262 2263 static int 2264 unp_listen(struct unpcb *unp, struct thread *td) 2265 { 2266 struct proc *p = td->td_proc; 2267 2268 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2269 UNP_ASSERT_TOKEN_HELD(unp); 2270 2271 KKASSERT(p); 2272 cru2x(p->p_ucred, &unp->unp_peercred); 2273 unp_setflags(unp, UNP_HAVEPCCACHED); 2274 return (0); 2275 } 2276 2277 static void 2278 unp_scan(struct mbuf *m0, void (*op)(struct file *, void *), void *data) 2279 { 2280 struct mbuf *m; 2281 struct file **rp; 2282 struct cmsghdr *cm; 2283 int i; 2284 int qfds; 2285 2286 while (m0) { 2287 for (m = m0; m; m = m->m_next) { 2288 if (m->m_type == MT_CONTROL && 2289 m->m_len >= sizeof(*cm)) { 2290 cm = mtod(m, struct cmsghdr *); 2291 if (cm->cmsg_level != SOL_SOCKET || 2292 cm->cmsg_type != SCM_RIGHTS) 2293 continue; 2294 qfds = (cm->cmsg_len - CMSG_LEN(0)) / 2295 sizeof(void *); 2296 rp = (struct file **)CMSG_DATA(cm); 2297 for (i = 0; i < qfds; i++) 2298 (*op)(*rp++, data); 2299 break; /* XXX, but saves time */ 2300 } 2301 } 2302 m0 = m0->m_nextpkt; 2303 } 2304 } 2305 2306 /* 2307 * Discard a fp previously held in a unix domain socket mbuf. To 2308 * avoid blowing out the kernel stack due to contrived chain-reactions 2309 * we may have to defer the operation to a dedicated taskqueue. 2310 * 2311 * Caller holds unp_rights_token. 2312 */ 2313 static void 2314 unp_discard(struct file *fp, void *data __unused) 2315 { 2316 unp_del_right(fp); 2317 if (unp_fp2unpcb(fp) != NULL) { 2318 struct unp_defdiscard *d; 2319 2320 /* 2321 * This fp is a Unix domain socket itself and fdrop() 2322 * it here directly may cause deep unp_discard() 2323 * recursion, so the fdrop() is defered to the 2324 * dedicated taskqueue. 2325 */ 2326 d = kmalloc(sizeof(*d), M_UNPCB, M_WAITOK); 2327 d->fp = fp; 2328 2329 spin_lock(&unp_defdiscard_spin); 2330 SLIST_INSERT_HEAD(&unp_defdiscard_head, d, next); 2331 spin_unlock(&unp_defdiscard_spin); 2332 2333 taskqueue_enqueue(unp_taskqueue, &unp_defdiscard_task); 2334 } else { 2335 /* This fp is not a Unix domain socket */ 2336 fdrop(fp); 2337 } 2338 } 2339 2340 /* 2341 * NOTE: 2342 * unp_token must be held before calling this function to avoid name 2343 * resolution and v_socket accessing races, especially racing against 2344 * the unp_detach(). 2345 * 2346 * NOTE: 2347 * For anyone caring about unconnected Unix domain socket sending 2348 * performance, other approach could be taken... 2349 */ 2350 static int 2351 unp_find_lockref(struct sockaddr *nam, struct thread *td, short type, 2352 struct unpcb **unp_ret) 2353 { 2354 struct proc *p = td->td_proc; 2355 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 2356 struct vnode *vp = NULL; 2357 struct socket *so; 2358 struct unpcb *unp; 2359 int error, len; 2360 struct nlookupdata nd; 2361 char buf[SOCK_MAXADDRLEN]; 2362 2363 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2364 2365 *unp_ret = NULL; 2366 2367 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 2368 if (len <= 0) { 2369 error = EINVAL; 2370 goto failed; 2371 } 2372 strncpy(buf, soun->sun_path, len); 2373 buf[len] = 0; 2374 2375 error = nlookup_init(&nd, buf, UIO_SYSSPACE, NLC_FOLLOW); 2376 if (error == 0) 2377 error = nlookup(&nd); 2378 if (error == 0) 2379 error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp); 2380 nlookup_done(&nd); 2381 if (error) { 2382 vp = NULL; 2383 goto failed; 2384 } 2385 2386 if (vp->v_type != VSOCK) { 2387 error = ENOTSOCK; 2388 goto failed; 2389 } 2390 error = VOP_EACCESS(vp, VWRITE, p->p_ucred); 2391 if (error) 2392 goto failed; 2393 so = vp->v_socket; 2394 if (so == NULL) { 2395 error = ECONNREFUSED; 2396 goto failed; 2397 } 2398 if (so->so_type != type) { 2399 error = EPROTOTYPE; 2400 goto failed; 2401 } 2402 2403 /* Lock this unp. */ 2404 unp = unp_getsocktoken(so); 2405 if (!UNP_ISATTACHED(unp)) { 2406 unp_reltoken(unp); 2407 error = ECONNREFUSED; 2408 goto failed; 2409 } 2410 /* And keep this unp referenced. */ 2411 unp_reference(unp); 2412 2413 /* Done! */ 2414 *unp_ret = unp; 2415 error = 0; 2416 failed: 2417 if (vp != NULL) 2418 vput(vp); 2419 return error; 2420 } 2421 2422 static int 2423 unp_connect_pair(struct unpcb *unp, struct unpcb *unp2) 2424 { 2425 struct socket *so = unp->unp_socket; 2426 struct socket *so2 = unp2->unp_socket; 2427 2428 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2429 UNP_ASSERT_TOKEN_HELD(unp); 2430 UNP_ASSERT_TOKEN_HELD(unp2); 2431 2432 KASSERT(so->so_type == so2->so_type, 2433 ("socket type mismatch, so %d, so2 %d", so->so_type, so2->so_type)); 2434 2435 if (!UNP_ISATTACHED(unp)) 2436 return EINVAL; 2437 if (!UNP_ISATTACHED(unp2)) 2438 return ECONNREFUSED; 2439 2440 KASSERT(unp->unp_conn == NULL, ("unp is already connected")); 2441 unp->unp_conn = unp2; 2442 2443 switch (so->so_type) { 2444 case SOCK_DGRAM: 2445 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 2446 soisconnected(so); 2447 break; 2448 2449 case SOCK_STREAM: 2450 case SOCK_SEQPACKET: 2451 KASSERT(unp2->unp_conn == NULL, ("unp2 is already connected")); 2452 unp2->unp_conn = unp; 2453 soisconnected(so); 2454 soisconnected(so2); 2455 break; 2456 2457 default: 2458 panic("unp_connect_pair: unknown socket type %d", so->so_type); 2459 } 2460 return 0; 2461 } 2462 2463 static void 2464 unp_drop(struct unpcb *unp, int error) 2465 { 2466 struct unp_global_head *head; 2467 struct unpcb *unp2; 2468 2469 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2470 UNP_ASSERT_TOKEN_HELD(unp); 2471 2472 KASSERT((unp->unp_flags & (UNP_DETACHED | UNP_DROPPED)) == 0, 2473 ("unp is dropped")); 2474 2475 /* Mark this unp as detached. */ 2476 unp_setflags(unp, UNP_DETACHED); 2477 2478 /* Remove this unp from the global unp list. */ 2479 head = unp_globalhead(unp->unp_socket->so_type); 2480 KASSERT(head->count > 0, ("invalid unp count")); 2481 TAILQ_REMOVE(&head->list, unp, unp_link); 2482 head->count--; 2483 2484 /* Disconnect all. */ 2485 unp_disconnect(unp, error); 2486 while ((unp2 = LIST_FIRST(&unp->unp_refs)) != NULL) { 2487 lwkt_getpooltoken(unp2); 2488 unp_disconnect(unp2, ECONNRESET); 2489 lwkt_relpooltoken(unp2); 2490 } 2491 unp_setflags(unp, UNP_DROPPED); 2492 2493 /* Try freeing this unp. */ 2494 unp_free(unp); 2495 } 2496 2497 static void 2498 unp_defdiscard_taskfunc(void *arg __unused, int pending __unused) 2499 { 2500 struct unp_defdiscard *d; 2501 2502 spin_lock(&unp_defdiscard_spin); 2503 while ((d = SLIST_FIRST(&unp_defdiscard_head)) != NULL) { 2504 SLIST_REMOVE_HEAD(&unp_defdiscard_head, next); 2505 spin_unlock(&unp_defdiscard_spin); 2506 2507 fdrop(d->fp); 2508 kfree(d, M_UNPCB); 2509 2510 spin_lock(&unp_defdiscard_spin); 2511 } 2512 spin_unlock(&unp_defdiscard_spin); 2513 } 2514