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 }; 147 148 static int unp_attach (struct socket *, struct pru_attach_info *); 149 static void unp_detach (struct unpcb *); 150 static int unp_bind (struct unpcb *,struct sockaddr *, struct thread *); 151 static int unp_connect (struct socket *,struct sockaddr *, 152 struct thread *); 153 static void unp_disconnect(struct unpcb *, int); 154 static void unp_shutdown (struct unpcb *); 155 static void unp_gc(void *, int); 156 #ifdef UNP_GC_ALLFILES 157 static int unp_gc_clearmarks(struct file *, void *); 158 static int unp_gc_checkmarks(struct file *, void *); 159 static int unp_gc_checkrefs(struct file *, void *); 160 static void unp_mark(struct file *, void *data); 161 #endif 162 static void unp_scan (struct mbuf *, void (*)(struct file *, void *), 163 void *data); 164 static void unp_discard (struct file *, void *); 165 static int unp_internalize (struct mbuf *, struct thread *); 166 static int unp_listen (struct unpcb *, struct thread *); 167 static void unp_fp_externalize(struct lwp *lp, struct file *fp, int fd, 168 int flags); 169 static int unp_find_lockref(struct sockaddr *nam, struct thread *td, 170 short type, struct unpcb **unp_ret); 171 static int unp_connect_pair(struct unpcb *unp, struct unpcb *unp2); 172 static void unp_drop(struct unpcb *unp, int error); 173 static void unp_defdiscard_taskfunc(void *, int); 174 175 static int unp_rights; /* file descriptors in flight */ 176 static struct lwkt_token unp_rights_token = 177 LWKT_TOKEN_INITIALIZER(unp_rights_token); 178 static struct task unp_gc_task; 179 static struct unpcb *unp_gc_marker; 180 181 SYSCTL_DECL(_net_local); 182 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, 183 "File descriptors in flight"); 184 185 /* 186 * SMP Considerations: 187 * 188 * Since unp_token will be automaticly released upon execution of 189 * blocking code, we need to reference unp_conn before any possible 190 * blocking code to prevent it from being ripped behind our back. 191 * 192 * Any adjustment to unp->unp_conn requires both the global unp_token 193 * AND the per-unp token (lwkt_token_pool_lookup(unp)) to be held. 194 * 195 * Any access to so_pcb to obtain unp requires the pool token for 196 * unp to be held. 197 */ 198 199 static __inline void 200 unp_reference(struct unpcb *unp) 201 { 202 /* 0->1 transition will not work */ 203 KKASSERT(unp->unp_refcnt > 0); 204 atomic_add_int(&unp->unp_refcnt, 1); 205 } 206 207 static __inline void 208 unp_free(struct unpcb *unp) 209 { 210 KKASSERT(unp->unp_refcnt > 0); 211 if (atomic_fetchadd_int(&unp->unp_refcnt, -1) == 1) 212 unp_detach(unp); 213 } 214 215 static __inline struct unpcb * 216 unp_getsocktoken(struct socket *so) 217 { 218 struct unpcb *unp; 219 220 /* 221 * The unp pointer is invalid until we verify that it is 222 * good by re-checking so_pcb AFTER obtaining the token. 223 */ 224 while ((unp = so->so_pcb) != NULL) { 225 lwkt_getpooltoken(unp); 226 if (unp == so->so_pcb) 227 break; 228 lwkt_relpooltoken(unp); 229 } 230 return unp; 231 } 232 233 static __inline void 234 unp_reltoken(struct unpcb *unp) 235 { 236 if (unp != NULL) 237 lwkt_relpooltoken(unp); 238 } 239 240 static __inline void 241 unp_setflags(struct unpcb *unp, int flags) 242 { 243 atomic_set_int(&unp->unp_flags, flags); 244 } 245 246 static __inline void 247 unp_clrflags(struct unpcb *unp, int flags) 248 { 249 atomic_clear_int(&unp->unp_flags, flags); 250 } 251 252 static __inline struct unp_global_head * 253 unp_globalhead(short type) 254 { 255 switch (type) { 256 case SOCK_STREAM: 257 return &unp_stream_head; 258 case SOCK_DGRAM: 259 return &unp_dgram_head; 260 case SOCK_SEQPACKET: 261 return &unp_seqpkt_head; 262 default: 263 panic("unknown socket type %d", type); 264 } 265 } 266 267 static __inline struct unpcb * 268 unp_fp2unpcb(struct file *fp) 269 { 270 struct socket *so; 271 272 if (fp->f_type != DTYPE_SOCKET) 273 return NULL; 274 275 so = fp->f_data; 276 if (so == NULL) 277 return NULL; 278 279 if (so->so_proto->pr_domain != &localdomain) 280 return NULL; 281 282 return so->so_pcb; 283 } 284 285 static __inline void 286 unp_add_right(struct file *fp) 287 { 288 struct unpcb *unp; 289 290 ASSERT_LWKT_TOKEN_HELD(&unp_rights_token); 291 KASSERT(fp->f_count > 0, ("invalid f_count %d", fp->f_count)); 292 293 unp = unp_fp2unpcb(fp); 294 if (unp != NULL) { 295 unp->unp_fp = fp; 296 unp->unp_msgcount++; 297 } 298 fp->f_msgcount++; 299 unp_rights++; 300 } 301 302 static __inline void 303 unp_del_right(struct file *fp) 304 { 305 struct unpcb *unp; 306 307 ASSERT_LWKT_TOKEN_HELD(&unp_rights_token); 308 KASSERT(fp->f_count > 0, ("invalid f_count %d", fp->f_count)); 309 310 unp = unp_fp2unpcb(fp); 311 if (unp != NULL) { 312 KASSERT(unp->unp_msgcount > 0, 313 ("invalid unp msgcount %d", unp->unp_msgcount)); 314 unp->unp_msgcount--; 315 if (unp->unp_msgcount == 0) 316 unp->unp_fp = NULL; 317 } 318 fp->f_msgcount--; 319 unp_rights--; 320 } 321 322 /* 323 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort() 324 * will sofree() it when we return. 325 */ 326 static void 327 uipc_abort(netmsg_t msg) 328 { 329 struct unpcb *unp; 330 int error; 331 332 lwkt_gettoken(&unp_token); 333 unp = unp_getsocktoken(msg->base.nm_so); 334 335 if (UNP_ISATTACHED(unp)) { 336 unp_drop(unp, ECONNABORTED); 337 error = 0; 338 } else { 339 error = EINVAL; 340 } 341 342 unp_reltoken(unp); 343 lwkt_reltoken(&unp_token); 344 345 lwkt_replymsg(&msg->lmsg, error); 346 } 347 348 static void 349 uipc_accept(netmsg_t msg) 350 { 351 struct unpcb *unp; 352 int error; 353 354 lwkt_gettoken(&unp_token); 355 unp = unp_getsocktoken(msg->base.nm_so); 356 357 if (!UNP_ISATTACHED(unp)) { 358 error = EINVAL; 359 } else { 360 struct unpcb *unp2 = unp->unp_conn; 361 362 /* 363 * Pass back name of connected socket, 364 * if it was bound and we are still connected 365 * (our peer may have closed already!). 366 */ 367 if (unp2 && unp2->unp_addr) { 368 unp_reference(unp2); 369 *msg->accept.nm_nam = dup_sockaddr( 370 (struct sockaddr *)unp2->unp_addr); 371 unp_free(unp2); 372 } else { 373 *msg->accept.nm_nam = dup_sockaddr(&sun_noname); 374 } 375 error = 0; 376 } 377 378 unp_reltoken(unp); 379 lwkt_reltoken(&unp_token); 380 381 lwkt_replymsg(&msg->lmsg, error); 382 } 383 384 static void 385 uipc_attach(netmsg_t msg) 386 { 387 int error; 388 389 lwkt_gettoken(&unp_token); 390 391 KASSERT(msg->base.nm_so->so_pcb == NULL, ("double unp attach")); 392 error = unp_attach(msg->base.nm_so, msg->attach.nm_ai); 393 394 lwkt_reltoken(&unp_token); 395 lwkt_replymsg(&msg->lmsg, error); 396 } 397 398 static void 399 uipc_bind(netmsg_t msg) 400 { 401 struct unpcb *unp; 402 int error; 403 404 lwkt_gettoken(&unp_token); 405 unp = unp_getsocktoken(msg->base.nm_so); 406 407 if (UNP_ISATTACHED(unp)) 408 error = unp_bind(unp, msg->bind.nm_nam, msg->bind.nm_td); 409 else 410 error = EINVAL; 411 412 unp_reltoken(unp); 413 lwkt_reltoken(&unp_token); 414 415 lwkt_replymsg(&msg->lmsg, error); 416 } 417 418 static void 419 uipc_connect(netmsg_t msg) 420 { 421 int error; 422 423 error = unp_connect(msg->base.nm_so, msg->connect.nm_nam, 424 msg->connect.nm_td); 425 lwkt_replymsg(&msg->lmsg, error); 426 } 427 428 static void 429 uipc_connect2(netmsg_t msg) 430 { 431 int error; 432 433 error = unp_connect2(msg->connect2.nm_so1, msg->connect2.nm_so2, 434 msg->connect2.nm_cred); 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 /* 677 * Include creds if the receive side wants them, even if 678 * the send side did not send them. 679 */ 680 if (so2->so_options & SO_PASSCRED) { 681 struct mbuf **mp; 682 struct cmsghdr *cm; 683 struct cmsgcred cred; 684 struct mbuf *ncon; 685 686 mp = &control; 687 while ((ncon = *mp) != NULL) { 688 cm = mtod(ncon, struct cmsghdr *); 689 if (cm->cmsg_type == SCM_CREDS && 690 cm->cmsg_level == SOL_SOCKET) 691 break; 692 mp = &ncon->m_next; 693 } 694 if (ncon == NULL) { 695 ncon = sbcreatecontrol(&cred, sizeof(cred), 696 SCM_CREDS, SOL_SOCKET); 697 unp_internalize(ncon, msg->send.nm_td); 698 *mp = ncon; 699 } 700 } 701 702 if (unp->unp_addr) 703 from = (struct sockaddr *)unp->unp_addr; 704 else 705 from = &sun_noname; 706 707 lwkt_gettoken(&so2->so_rcv.ssb_token); 708 if (ssb_appendaddr(&so2->so_rcv, from, m, control)) { 709 sorwakeup(so2); 710 m = NULL; 711 control = NULL; 712 } else { 713 error = ENOBUFS; 714 } 715 lwkt_reltoken(&so2->so_rcv.ssb_token); 716 717 unp_free(unp2); 718 break; 719 } 720 721 case SOCK_STREAM: 722 case SOCK_SEQPACKET: 723 /* Connect if not connected yet. */ 724 /* 725 * Note: A better implementation would complain 726 * if not equal to the peer's address. 727 */ 728 if (unp->unp_conn == NULL) { 729 if (msg->send.nm_addr) { 730 error = unp_connect(so, 731 msg->send.nm_addr, 732 msg->send.nm_td); 733 if (error) 734 break; /* XXX */ 735 } 736 /* 737 * NOTE: 738 * unp_conn still could be NULL, even if the 739 * above unp_connect() succeeds; since the 740 * current unp's token could be released due 741 * to blocking operations after unp_conn is 742 * assigned. 743 */ 744 if (unp->unp_conn == NULL) { 745 error = ENOTCONN; 746 break; 747 } 748 } 749 if (so->so_state & SS_CANTSENDMORE) { 750 error = EPIPE; 751 break; 752 } 753 754 unp2 = unp->unp_conn; 755 KASSERT(unp2 != NULL, ("unp is not connected")); 756 so2 = unp2->unp_socket; 757 758 unp_reference(unp2); 759 760 /* 761 * Send to paired receive port, and then reduce 762 * send buffer hiwater marks to maintain backpressure. 763 * Wake up readers. 764 */ 765 lwkt_gettoken(&so2->so_rcv.ssb_token); 766 if (control) { 767 if (ssb_appendcontrol(&so2->so_rcv, m, control)) { 768 control = NULL; 769 m = NULL; 770 } 771 } else if (so->so_type == SOCK_SEQPACKET) { 772 sbappendrecord(&so2->so_rcv.sb, m); 773 m = NULL; 774 } else { 775 sbappend(&so2->so_rcv.sb, m); 776 m = NULL; 777 } 778 779 /* 780 * Because we are transfering mbufs directly to the 781 * peer socket we have to use SSB_STOP on the sender 782 * to prevent it from building up infinite mbufs. 783 */ 784 if (so2->so_rcv.ssb_cc >= so->so_snd.ssb_hiwat || 785 so2->so_rcv.ssb_mbcnt >= so->so_snd.ssb_mbmax 786 ) { 787 atomic_set_int(&so->so_snd.ssb_flags, SSB_STOP); 788 } 789 lwkt_reltoken(&so2->so_rcv.ssb_token); 790 sorwakeup(so2); 791 792 unp_free(unp2); 793 break; 794 795 default: 796 panic("uipc_send unknown socktype"); 797 } 798 799 /* 800 * SEND_EOF is equivalent to a SEND followed by a SHUTDOWN. 801 */ 802 if (msg->send.nm_flags & PRUS_EOF) { 803 socantsendmore(so); 804 unp_shutdown(unp); 805 } 806 807 if (control && error != 0) 808 unp_dispose(control); 809 release: 810 unp_reltoken(unp); 811 wakeup_end_delayed(); 812 813 if (control) 814 m_freem(control); 815 if (m) 816 m_freem(m); 817 lwkt_replymsg(&msg->lmsg, error); 818 } 819 820 /* 821 * MPSAFE 822 */ 823 static void 824 uipc_sense(netmsg_t msg) 825 { 826 struct unpcb *unp; 827 struct socket *so; 828 struct stat *sb; 829 int error; 830 831 so = msg->base.nm_so; 832 sb = msg->sense.nm_stat; 833 834 /* 835 * so_pcb is only modified with both the global and the unp 836 * pool token held. 837 */ 838 unp = unp_getsocktoken(so); 839 840 if (!UNP_ISATTACHED(unp)) { 841 error = EINVAL; 842 goto done; 843 } 844 845 sb->st_blksize = so->so_snd.ssb_hiwat; 846 sb->st_dev = NOUDEV; 847 error = 0; 848 done: 849 unp_reltoken(unp); 850 lwkt_replymsg(&msg->lmsg, error); 851 } 852 853 static void 854 uipc_shutdown(netmsg_t msg) 855 { 856 struct socket *so; 857 struct unpcb *unp; 858 int error; 859 860 /* 861 * so_pcb is only modified with both the global and the unp 862 * pool token held. 863 */ 864 so = msg->base.nm_so; 865 unp = unp_getsocktoken(so); 866 867 if (UNP_ISATTACHED(unp)) { 868 socantsendmore(so); 869 unp_shutdown(unp); 870 error = 0; 871 } else { 872 error = EINVAL; 873 } 874 875 unp_reltoken(unp); 876 lwkt_replymsg(&msg->lmsg, error); 877 } 878 879 static void 880 uipc_sockaddr(netmsg_t msg) 881 { 882 struct unpcb *unp; 883 int error; 884 885 /* 886 * so_pcb is only modified with both the global and the unp 887 * pool token held. 888 */ 889 unp = unp_getsocktoken(msg->base.nm_so); 890 891 if (UNP_ISATTACHED(unp)) { 892 if (unp->unp_addr) { 893 *msg->sockaddr.nm_nam = 894 dup_sockaddr((struct sockaddr *)unp->unp_addr); 895 } 896 error = 0; 897 } else { 898 error = EINVAL; 899 } 900 901 unp_reltoken(unp); 902 lwkt_replymsg(&msg->lmsg, error); 903 } 904 905 struct pr_usrreqs uipc_usrreqs = { 906 .pru_abort = uipc_abort, 907 .pru_accept = uipc_accept, 908 .pru_attach = uipc_attach, 909 .pru_bind = uipc_bind, 910 .pru_connect = uipc_connect, 911 .pru_connect2 = uipc_connect2, 912 .pru_control = pr_generic_notsupp, 913 .pru_detach = uipc_detach, 914 .pru_disconnect = uipc_disconnect, 915 .pru_listen = uipc_listen, 916 .pru_peeraddr = uipc_peeraddr, 917 .pru_rcvd = uipc_rcvd, 918 .pru_rcvoob = pr_generic_notsupp, 919 .pru_send = uipc_send, 920 .pru_sense = uipc_sense, 921 .pru_shutdown = uipc_shutdown, 922 .pru_sockaddr = uipc_sockaddr, 923 .pru_sosend = sosend, 924 .pru_soreceive = soreceive 925 }; 926 927 void 928 uipc_ctloutput(netmsg_t msg) 929 { 930 struct socket *so; 931 struct sockopt *sopt; 932 struct unpcb *unp; 933 int error = 0; 934 935 so = msg->base.nm_so; 936 sopt = msg->ctloutput.nm_sopt; 937 938 lwkt_gettoken(&unp_token); 939 unp = unp_getsocktoken(so); 940 941 if (!UNP_ISATTACHED(unp)) { 942 error = EINVAL; 943 goto done; 944 } 945 946 switch (sopt->sopt_dir) { 947 case SOPT_GET: 948 switch (sopt->sopt_name) { 949 case LOCAL_PEERCRED: 950 if (unp->unp_flags & UNP_HAVEPC) 951 soopt_from_kbuf(sopt, &unp->unp_peercred, 952 sizeof(unp->unp_peercred)); 953 else { 954 if (so->so_type == SOCK_STREAM) 955 error = ENOTCONN; 956 else if (so->so_type == SOCK_SEQPACKET) 957 error = ENOTCONN; 958 else 959 error = EINVAL; 960 } 961 break; 962 default: 963 error = EOPNOTSUPP; 964 break; 965 } 966 break; 967 case SOPT_SET: 968 default: 969 error = EOPNOTSUPP; 970 break; 971 } 972 973 done: 974 unp_reltoken(unp); 975 lwkt_reltoken(&unp_token); 976 977 lwkt_replymsg(&msg->lmsg, error); 978 } 979 980 /* 981 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 982 * for stream sockets, although the total for sender and receiver is 983 * actually only PIPSIZ. 984 * 985 * Datagram sockets really use the sendspace as the maximum datagram size, 986 * and don't really want to reserve the sendspace. Their recvspace should 987 * be large enough for at least one max-size datagram plus address. 988 * 989 * We want the local send/recv space to be significant larger then lo0's 990 * mtu of 16384. 991 * 992 * We no longer need to worry about avoiding the windows scaling option. 993 * Programs which use unix domain sockets expect larger defaults these days. 994 */ 995 #ifndef PIPSIZ 996 #define PIPSIZ 65536 997 #endif 998 static u_long unpst_sendspace = PIPSIZ; 999 static u_long unpst_recvspace = PIPSIZ; 1000 static u_long unpdg_sendspace = PIPSIZ; /* really max datagram size */ 1001 static u_long unpdg_recvspace = PIPSIZ; 1002 static u_long unpsp_sendspace = PIPSIZ; /* really max datagram size */ 1003 static u_long unpsp_recvspace = PIPSIZ; 1004 1005 SYSCTL_DECL(_net_local_stream); 1006 SYSCTL_DECL(_net_local_dgram); 1007 SYSCTL_DECL(_net_local_seqpacket); 1008 1009 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 1010 &unpst_sendspace, 0, "Size of stream socket send buffer"); 1011 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 1012 &unpst_recvspace, 0, "Size of stream socket receive buffer"); 1013 1014 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 1015 &unpdg_sendspace, 0, "Max datagram socket size"); 1016 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 1017 &unpdg_recvspace, 0, "Size of datagram socket receive buffer"); 1018 1019 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW, 1020 &unpsp_sendspace, 0, "Default seqpacket send space."); 1021 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW, 1022 &unpsp_recvspace, 0, "Default seqpacket receive space."); 1023 1024 1025 static int 1026 unp_attach(struct socket *so, struct pru_attach_info *ai) 1027 { 1028 struct unp_global_head *head; 1029 struct unpcb *unp; 1030 int error; 1031 1032 lwkt_gettoken(&unp_token); 1033 1034 if (so->so_snd.ssb_hiwat == 0 || so->so_rcv.ssb_hiwat == 0) { 1035 switch (so->so_type) { 1036 case SOCK_STREAM: 1037 error = soreserve(so, unpst_sendspace, unpst_recvspace, 1038 ai->sb_rlimit); 1039 break; 1040 case SOCK_DGRAM: 1041 error = soreserve(so, unpdg_sendspace, unpdg_recvspace, 1042 ai->sb_rlimit); 1043 break; 1044 case SOCK_SEQPACKET: 1045 error = soreserve(so, unpsp_sendspace, unpsp_recvspace, 1046 ai->sb_rlimit); 1047 break; 1048 default: 1049 panic("unp_attach"); 1050 } 1051 if (error) 1052 goto failed; 1053 } 1054 1055 /* 1056 * In order to support sendfile we have to set either SSB_STOPSUPP 1057 * or SSB_PREALLOC. Unix domain sockets use the SSB_STOP flow 1058 * control mechanism. 1059 */ 1060 if (so->so_type == SOCK_STREAM) { 1061 atomic_set_int(&so->so_rcv.ssb_flags, SSB_STOPSUPP); 1062 atomic_set_int(&so->so_snd.ssb_flags, SSB_STOPSUPP); 1063 } 1064 1065 unp = kmalloc(sizeof(*unp), M_UNPCB, M_WAITOK | M_ZERO | M_NULLOK); 1066 if (unp == NULL) { 1067 error = ENOBUFS; 1068 goto failed; 1069 } 1070 unp->unp_refcnt = 1; 1071 unp->unp_gencnt = ++unp_gencnt; 1072 LIST_INIT(&unp->unp_refs); 1073 unp->unp_socket = so; 1074 unp->unp_rvnode = ai->fd_rdir; /* jail cruft XXX JH */ 1075 so->so_pcb = (caddr_t)unp; 1076 soreference(so); 1077 1078 head = unp_globalhead(so->so_type); 1079 TAILQ_INSERT_TAIL(&head->list, unp, unp_link); 1080 head->count++; 1081 error = 0; 1082 failed: 1083 lwkt_reltoken(&unp_token); 1084 return error; 1085 } 1086 1087 static void 1088 unp_detach(struct unpcb *unp) 1089 { 1090 struct socket *so; 1091 1092 lwkt_gettoken(&unp_token); 1093 lwkt_getpooltoken(unp); 1094 1095 so = unp->unp_socket; 1096 1097 unp->unp_gencnt = ++unp_gencnt; 1098 if (unp->unp_vnode) { 1099 unp->unp_vnode->v_socket = NULL; 1100 vrele(unp->unp_vnode); 1101 unp->unp_vnode = NULL; 1102 } 1103 soisdisconnected(so); 1104 KKASSERT(so->so_pcb == unp); 1105 so->so_pcb = NULL; /* both tokens required */ 1106 unp->unp_socket = NULL; 1107 1108 lwkt_relpooltoken(unp); 1109 lwkt_reltoken(&unp_token); 1110 1111 sofree(so); 1112 1113 KASSERT(unp->unp_conn == NULL, ("unp is still connected")); 1114 KASSERT(LIST_EMPTY(&unp->unp_refs), ("unp still has references")); 1115 1116 if (unp->unp_addr) 1117 kfree(unp->unp_addr, M_SONAME); 1118 kfree(unp, M_UNPCB); 1119 1120 if (unp_rights) 1121 taskqueue_enqueue(unp_taskqueue, &unp_gc_task); 1122 } 1123 1124 static int 1125 unp_bind(struct unpcb *unp, struct sockaddr *nam, struct thread *td) 1126 { 1127 struct proc *p = td->td_proc; 1128 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 1129 struct vnode *vp; 1130 struct vattr vattr; 1131 int error, namelen; 1132 struct nlookupdata nd; 1133 char buf[SOCK_MAXADDRLEN]; 1134 1135 ASSERT_LWKT_TOKEN_HELD(&unp_token); 1136 UNP_ASSERT_TOKEN_HELD(unp); 1137 1138 if (unp->unp_vnode != NULL) 1139 return EINVAL; 1140 1141 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 1142 if (namelen <= 0) 1143 return EINVAL; 1144 strncpy(buf, soun->sun_path, namelen); 1145 buf[namelen] = 0; /* null-terminate the string */ 1146 error = nlookup_init(&nd, buf, UIO_SYSSPACE, 1147 NLC_LOCKVP | NLC_CREATE | NLC_REFDVP); 1148 if (error == 0) 1149 error = nlookup(&nd); 1150 if (error == 0 && nd.nl_nch.ncp->nc_vp != NULL) 1151 error = EADDRINUSE; 1152 if (error == 0 && nd.nl_dvp == NULL) /* e.g. bind <mountpt> */ 1153 error = EINVAL; 1154 if (error) 1155 goto done; 1156 1157 VATTR_NULL(&vattr); 1158 vattr.va_type = VSOCK; 1159 vattr.va_mode = (ACCESSPERMS & ~p->p_fd->fd_cmask); 1160 error = VOP_NCREATE(&nd.nl_nch, nd.nl_dvp, &vp, nd.nl_cred, &vattr); 1161 if (error == 0) { 1162 if (unp->unp_vnode == NULL) { 1163 vp->v_socket = unp->unp_socket; 1164 unp->unp_vnode = vp; 1165 unp->unp_addr = (struct sockaddr_un *)dup_sockaddr(nam); 1166 vn_unlock(vp); 1167 } else { 1168 vput(vp); /* late race */ 1169 error = EINVAL; 1170 } 1171 } 1172 done: 1173 nlookup_done(&nd); 1174 return (error); 1175 } 1176 1177 static int 1178 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1179 { 1180 struct unpcb *unp, *unp2; 1181 int error, flags = 0; 1182 1183 lwkt_gettoken(&unp_token); 1184 1185 unp = unp_getsocktoken(so); 1186 if (!UNP_ISATTACHED(unp)) { 1187 error = EINVAL; 1188 goto failed; 1189 } 1190 1191 if ((unp->unp_flags & UNP_CONNECTING) || unp->unp_conn != NULL) { 1192 error = EISCONN; 1193 goto failed; 1194 } 1195 1196 flags = UNP_CONNECTING; 1197 unp_setflags(unp, flags); 1198 1199 error = unp_find_lockref(nam, td, so->so_type, &unp2); 1200 if (error) 1201 goto failed; 1202 /* 1203 * NOTE: 1204 * unp2 is locked and referenced. 1205 */ 1206 1207 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1208 struct socket *so2, *so3; 1209 struct unpcb *unp3; 1210 1211 so2 = unp2->unp_socket; 1212 if (!(so2->so_options & SO_ACCEPTCONN) || 1213 /* listen is not completed yet */ 1214 !(unp2->unp_flags & UNP_HAVEPCCACHED) || 1215 (so3 = sonewconn_faddr(so2, 0, NULL, 1216 TRUE /* keep ref */)) == NULL) { 1217 error = ECONNREFUSED; 1218 goto done; 1219 } 1220 /* so3 has a socket reference. */ 1221 1222 unp3 = unp_getsocktoken(so3); 1223 if (!UNP_ISATTACHED(unp3)) { 1224 unp_reltoken(unp3); 1225 /* 1226 * Already aborted; we only need to drop the 1227 * socket reference held by sonewconn_faddr(). 1228 */ 1229 sofree(so3); 1230 error = ECONNREFUSED; 1231 goto done; 1232 } 1233 unp_reference(unp3); 1234 /* 1235 * NOTE: 1236 * unp3 is locked and referenced. 1237 */ 1238 1239 /* 1240 * Release so3 socket reference held by sonewconn_faddr(). 1241 * Since we have referenced unp3, neither unp3 nor so3 will 1242 * be destroyed here. 1243 */ 1244 sofree(so3); 1245 1246 if (unp2->unp_addr != NULL) { 1247 unp3->unp_addr = (struct sockaddr_un *) 1248 dup_sockaddr((struct sockaddr *)unp2->unp_addr); 1249 } 1250 1251 /* 1252 * unp_peercred management: 1253 * 1254 * The connecter's (client's) credentials are copied 1255 * from its process structure at the time of connect() 1256 * (which is now). 1257 */ 1258 cru2x(td->td_proc->p_ucred, &unp3->unp_peercred); 1259 unp_setflags(unp3, UNP_HAVEPC); 1260 /* 1261 * The receiver's (server's) credentials are copied 1262 * from the unp_peercred member of socket on which the 1263 * former called listen(); unp_listen() cached that 1264 * process's credentials at that time so we can use 1265 * them now. 1266 */ 1267 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1268 ("unp_connect: listener without cached peercred")); 1269 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1270 sizeof(unp->unp_peercred)); 1271 unp_setflags(unp, UNP_HAVEPC); 1272 1273 error = unp_connect_pair(unp, unp3); 1274 if (error) 1275 soabort_direct(so3); 1276 1277 /* Done with unp3 */ 1278 unp_free(unp3); 1279 unp_reltoken(unp3); 1280 } else { 1281 error = unp_connect_pair(unp, unp2); 1282 } 1283 done: 1284 unp_free(unp2); 1285 unp_reltoken(unp2); 1286 failed: 1287 if (flags) 1288 unp_clrflags(unp, flags); 1289 unp_reltoken(unp); 1290 1291 lwkt_reltoken(&unp_token); 1292 return (error); 1293 } 1294 1295 /* 1296 * Connect two unix domain sockets together. 1297 * 1298 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1299 * pool token also be held. 1300 */ 1301 int 1302 unp_connect2(struct socket *so, struct socket *so2, struct ucred *cred) 1303 { 1304 struct unpcb *unp, *unp2; 1305 int error; 1306 1307 lwkt_gettoken(&unp_token); 1308 if (so2->so_type != so->so_type) { 1309 lwkt_reltoken(&unp_token); 1310 return (EPROTOTYPE); 1311 } 1312 unp = unp_getsocktoken(so); 1313 unp2 = unp_getsocktoken(so2); 1314 1315 cru2x(cred, &unp->unp_peercred); 1316 cru2x(cred, &unp2->unp_peercred); 1317 unp_setflags(unp, UNP_HAVEPC); 1318 unp_setflags(unp2, UNP_HAVEPC); 1319 1320 if (!UNP_ISATTACHED(unp)) { 1321 error = EINVAL; 1322 goto done; 1323 } 1324 if (!UNP_ISATTACHED(unp2)) { 1325 error = ECONNREFUSED; 1326 goto done; 1327 } 1328 1329 if (unp->unp_conn != NULL) { 1330 error = EISCONN; 1331 goto done; 1332 } 1333 if ((so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET) && 1334 unp2->unp_conn != NULL) { 1335 error = EISCONN; 1336 goto done; 1337 } 1338 1339 error = unp_connect_pair(unp, unp2); 1340 done: 1341 unp_reltoken(unp2); 1342 unp_reltoken(unp); 1343 lwkt_reltoken(&unp_token); 1344 return (error); 1345 } 1346 1347 /* 1348 * Disconnect a unix domain socket pair. 1349 * 1350 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1351 * pool token also be held. 1352 */ 1353 static void 1354 unp_disconnect(struct unpcb *unp, int error) 1355 { 1356 struct socket *so = unp->unp_socket; 1357 struct unpcb *unp2; 1358 1359 ASSERT_LWKT_TOKEN_HELD(&unp_token); 1360 UNP_ASSERT_TOKEN_HELD(unp); 1361 1362 if (error) 1363 so->so_error = error; 1364 1365 while ((unp2 = unp->unp_conn) != NULL) { 1366 lwkt_getpooltoken(unp2); 1367 if (unp2 == unp->unp_conn) 1368 break; 1369 lwkt_relpooltoken(unp2); 1370 } 1371 if (unp2 == NULL) 1372 return; 1373 /* unp2 is locked. */ 1374 1375 KASSERT((unp2->unp_flags & UNP_DROPPED) == 0, ("unp2 was dropped")); 1376 1377 unp->unp_conn = NULL; 1378 1379 switch (so->so_type) { 1380 case SOCK_DGRAM: 1381 LIST_REMOVE(unp, unp_reflink); 1382 soclrstate(so, SS_ISCONNECTED); 1383 break; 1384 1385 case SOCK_STREAM: 1386 case SOCK_SEQPACKET: 1387 /* 1388 * Keep a reference before clearing the unp_conn 1389 * to avoid racing uipc_detach()/uipc_abort() in 1390 * other thread. 1391 */ 1392 unp_reference(unp2); 1393 KASSERT(unp2->unp_conn == unp, ("unp_conn mismatch")); 1394 unp2->unp_conn = NULL; 1395 1396 soisdisconnected(so); 1397 soisdisconnected(unp2->unp_socket); 1398 1399 unp_free(unp2); 1400 break; 1401 } 1402 1403 lwkt_relpooltoken(unp2); 1404 } 1405 1406 #ifdef notdef 1407 void 1408 unp_abort(struct unpcb *unp) 1409 { 1410 lwkt_gettoken(&unp_token); 1411 unp_free(unp); 1412 lwkt_reltoken(&unp_token); 1413 } 1414 #endif 1415 1416 static int 1417 prison_unpcb(struct thread *td, struct unpcb *unp) 1418 { 1419 struct proc *p; 1420 1421 if (td == NULL) 1422 return (0); 1423 if ((p = td->td_proc) == NULL) 1424 return (0); 1425 if (!p->p_ucred->cr_prison) 1426 return (0); 1427 if (p->p_fd->fd_rdir == unp->unp_rvnode) 1428 return (0); 1429 return (1); 1430 } 1431 1432 static int 1433 unp_pcblist(SYSCTL_HANDLER_ARGS) 1434 { 1435 struct unp_global_head *head = arg1; 1436 int error, i, n; 1437 struct unpcb *unp, *marker; 1438 1439 KKASSERT(curproc != NULL); 1440 1441 /* 1442 * The process of preparing the PCB list is too time-consuming and 1443 * resource-intensive to repeat twice on every request. 1444 */ 1445 if (req->oldptr == NULL) { 1446 n = head->count; 1447 req->oldidx = (n + n/8) * sizeof(struct xunpcb); 1448 return 0; 1449 } 1450 1451 if (req->newptr != NULL) 1452 return EPERM; 1453 1454 marker = kmalloc(sizeof(*marker), M_UNPCB, M_WAITOK | M_ZERO); 1455 marker->unp_flags |= UNP_MARKER; 1456 1457 lwkt_gettoken(&unp_token); 1458 1459 n = head->count; 1460 i = 0; 1461 error = 0; 1462 1463 TAILQ_INSERT_HEAD(&head->list, marker, unp_link); 1464 while ((unp = TAILQ_NEXT(marker, unp_link)) != NULL && i < n) { 1465 struct xunpcb xu; 1466 1467 TAILQ_REMOVE(&head->list, marker, unp_link); 1468 TAILQ_INSERT_AFTER(&head->list, unp, marker, unp_link); 1469 1470 if (unp->unp_flags & UNP_MARKER) 1471 continue; 1472 if (prison_unpcb(req->td, unp)) 1473 continue; 1474 1475 xu.xu_len = sizeof(xu); 1476 xu.xu_unpp = unp; 1477 1478 /* 1479 * NOTE: 1480 * unp->unp_addr and unp->unp_conn are protected by 1481 * unp_token. So if we want to get rid of unp_token 1482 * or reduce the coverage of unp_token, care must be 1483 * taken. 1484 */ 1485 if (unp->unp_addr) { 1486 bcopy(unp->unp_addr, &xu.xu_addr, 1487 unp->unp_addr->sun_len); 1488 } 1489 if (unp->unp_conn && unp->unp_conn->unp_addr) { 1490 bcopy(unp->unp_conn->unp_addr, 1491 &xu.xu_caddr, 1492 unp->unp_conn->unp_addr->sun_len); 1493 } 1494 bcopy(unp, &xu.xu_unp, sizeof(*unp)); 1495 sotoxsocket(unp->unp_socket, &xu.xu_socket); 1496 1497 /* NOTE: This could block and temporarily release unp_token */ 1498 error = SYSCTL_OUT(req, &xu, sizeof(xu)); 1499 if (error) 1500 break; 1501 ++i; 1502 } 1503 TAILQ_REMOVE(&head->list, marker, unp_link); 1504 1505 lwkt_reltoken(&unp_token); 1506 1507 kfree(marker, M_UNPCB); 1508 return error; 1509 } 1510 1511 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1512 &unp_dgram_head, 0, unp_pcblist, "S,xunpcb", 1513 "List of active local datagram sockets"); 1514 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1515 &unp_stream_head, 0, unp_pcblist, "S,xunpcb", 1516 "List of active local stream sockets"); 1517 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist, CTLFLAG_RD, 1518 &unp_seqpkt_head, 0, unp_pcblist, "S,xunpcb", 1519 "List of active local seqpacket sockets"); 1520 1521 static void 1522 unp_shutdown(struct unpcb *unp) 1523 { 1524 struct socket *so; 1525 1526 if ((unp->unp_socket->so_type == SOCK_STREAM || 1527 unp->unp_socket->so_type == SOCK_SEQPACKET) && 1528 unp->unp_conn != NULL && (so = unp->unp_conn->unp_socket)) { 1529 socantrcvmore(so); 1530 } 1531 } 1532 1533 #ifdef notdef 1534 void 1535 unp_drain(void) 1536 { 1537 lwkt_gettoken(&unp_token); 1538 lwkt_reltoken(&unp_token); 1539 } 1540 #endif 1541 1542 int 1543 unp_externalize(struct mbuf *rights, int flags) 1544 { 1545 struct thread *td = curthread; 1546 struct proc *p = td->td_proc; /* XXX */ 1547 struct lwp *lp = td->td_lwp; 1548 struct cmsghdr *cm = mtod(rights, struct cmsghdr *); 1549 int *fdp; 1550 int i; 1551 struct file **rp; 1552 struct file *fp; 1553 int newfds = (cm->cmsg_len - (CMSG_DATA(cm) - (u_char *)cm)) 1554 / sizeof(struct file *); 1555 int f; 1556 1557 lwkt_gettoken(&unp_rights_token); 1558 1559 /* 1560 * if the new FD's will not fit, then we free them all 1561 */ 1562 if (!fdavail(p, newfds)) { 1563 rp = (struct file **)CMSG_DATA(cm); 1564 for (i = 0; i < newfds; i++) { 1565 fp = *rp; 1566 /* 1567 * zero the pointer before calling unp_discard, 1568 * since it may end up in unp_gc().. 1569 */ 1570 *rp++ = NULL; 1571 unp_discard(fp, NULL); 1572 } 1573 lwkt_reltoken(&unp_rights_token); 1574 return (EMSGSIZE); 1575 } 1576 1577 /* 1578 * now change each pointer to an fd in the global table to 1579 * an integer that is the index to the local fd table entry 1580 * that we set up to point to the global one we are transferring. 1581 * Since the sizeof(struct file *) is bigger than or equal to 1582 * the sizeof(int), we do it in forward order. In that case, 1583 * an integer will always come in the same place or before its 1584 * corresponding struct file pointer. 1585 * 1586 * Hold revoke_token in 'shared' mode, so that we won't miss 1587 * the FREVOKED update on fps being externalized (fsetfd). 1588 */ 1589 lwkt_gettoken_shared(&revoke_token); 1590 fdp = (int *)CMSG_DATA(cm); 1591 rp = (struct file **)CMSG_DATA(cm); 1592 for (i = 0; i < newfds; i++) { 1593 if (fdalloc(p, 0, &f)) { 1594 int j; 1595 1596 /* 1597 * Previous fdavail() can't garantee 1598 * fdalloc() success due to SMP race. 1599 * Just clean up and return the same 1600 * error value as if fdavail() failed. 1601 */ 1602 lwkt_reltoken(&revoke_token); 1603 1604 /* Close externalized files */ 1605 for (j = 0; j < i; j++) 1606 kern_close(fdp[j]); 1607 /* Discard the rest of internal files */ 1608 for (; i < newfds; i++) 1609 unp_discard(rp[i], NULL); 1610 /* Wipe out the control message */ 1611 for (i = 0; i < newfds; i++) 1612 rp[i] = NULL; 1613 1614 lwkt_reltoken(&unp_rights_token); 1615 return (EMSGSIZE); 1616 } 1617 fp = rp[i]; 1618 unp_fp_externalize(lp, fp, f, flags); 1619 fdp[i] = f; 1620 } 1621 lwkt_reltoken(&revoke_token); 1622 1623 lwkt_reltoken(&unp_rights_token); 1624 1625 /* 1626 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1627 * differs. 1628 */ 1629 cm->cmsg_len = CMSG_LEN(newfds * sizeof(int)); 1630 rights->m_len = cm->cmsg_len; 1631 1632 return (0); 1633 } 1634 1635 static void 1636 unp_fp_externalize(struct lwp *lp, struct file *fp, int fd, int flags) 1637 { 1638 if (lp) { 1639 struct filedesc *fdp = lp->lwp_proc->p_fd; 1640 1641 KKASSERT(fd >= 0); 1642 if (fp->f_flag & FREVOKED) { 1643 struct file *fx; 1644 int error; 1645 1646 kprintf("Warning: revoked fp exiting unix socket\n"); 1647 error = falloc(lp, &fx, NULL); 1648 if (error == 0) { 1649 if (flags & MSG_CMSG_CLOEXEC) 1650 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1651 fsetfd(fdp, fx, fd); 1652 fdrop(fx); 1653 } else { 1654 fsetfd(fdp, NULL, fd); 1655 } 1656 } else { 1657 if (flags & MSG_CMSG_CLOEXEC) 1658 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1659 fsetfd(fdp, fp, fd); 1660 } 1661 } 1662 unp_del_right(fp); 1663 fdrop(fp); 1664 } 1665 1666 void 1667 unp_init(void) 1668 { 1669 TAILQ_INIT(&unp_stream_head.list); 1670 TAILQ_INIT(&unp_dgram_head.list); 1671 TAILQ_INIT(&unp_seqpkt_head.list); 1672 1673 SLIST_INIT(&unp_defdiscard_head); 1674 spin_init(&unp_defdiscard_spin, "unpdisc"); 1675 TASK_INIT(&unp_defdiscard_task, 0, unp_defdiscard_taskfunc, NULL); 1676 1677 /* 1678 * This implies that only one gc can be in-progress at any 1679 * given moment. 1680 */ 1681 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1682 1683 unp_gc_marker = kmalloc(sizeof(*unp_gc_marker), M_UNPCB, 1684 M_WAITOK | M_ZERO); 1685 unp_gc_marker->unp_flags |= UNP_MARKER; 1686 1687 /* 1688 * Create taskqueue for defered discard, and stick it to 1689 * the last CPU. 1690 */ 1691 unp_taskqueue = taskqueue_create("unp_taskq", M_WAITOK, 1692 taskqueue_thread_enqueue, &unp_taskqueue); 1693 taskqueue_start_threads(&unp_taskqueue, 1, TDPRI_KERN_DAEMON, 1694 ncpus - 1, "unp taskq"); 1695 } 1696 1697 static int 1698 unp_internalize(struct mbuf *control, struct thread *td) 1699 { 1700 struct proc *p = td->td_proc; 1701 struct filedesc *fdescp; 1702 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1703 struct file **rp; 1704 struct file *fp; 1705 int i, fd, *fdp; 1706 struct cmsgcred *cmcred; 1707 int oldfds; 1708 u_int newlen; 1709 int error; 1710 1711 KKASSERT(p); 1712 1713 /* 1714 * Make sure the message is reasonable, and either CREDS or RIGHTS. 1715 * 1716 * NOTE: overall message length does not have to be aligned, but the 1717 * data start does. 1718 */ 1719 if ((cm->cmsg_type != SCM_RIGHTS && cm->cmsg_type != SCM_CREDS) || 1720 cm->cmsg_level != SOL_SOCKET || 1721 control->m_len < sizeof(*cm) || /* control too small */ 1722 cm->cmsg_len < sizeof(*cm) || /* cmsg_len too small */ 1723 cm->cmsg_len > control->m_len) { /* cmsg_len too big */ 1724 return EINVAL; 1725 } 1726 1727 /* 1728 * Fill in credential information. 1729 */ 1730 if (cm->cmsg_type == SCM_CREDS) { 1731 cmcred = (struct cmsgcred *)CMSG_DATA(cm); 1732 cmcred->cmcred_pid = p->p_pid; 1733 cmcred->cmcred_uid = p->p_ucred->cr_ruid; 1734 cmcred->cmcred_gid = p->p_ucred->cr_rgid; 1735 cmcred->cmcred_euid = p->p_ucred->cr_uid; 1736 cmcred->cmcred_ngroups = MIN(p->p_ucred->cr_ngroups, 1737 CMGROUP_MAX); 1738 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1739 cmcred->cmcred_groups[i] = p->p_ucred->cr_groups[i]; 1740 return 0; 1741 } 1742 1743 /* 1744 * cmsghdr may not be aligned, do not allow calculation(s) to 1745 * go negative. 1746 * 1747 * Data must be aligned but the data length does not have to be. 1748 * 1749 * If there are multiple headers (XXX not supported) then the 1750 * next header will be aligned after the end of the possibly 1751 * unaligned data. 1752 */ 1753 if (cm->cmsg_len < CMSG_LEN(0)) { 1754 return EINVAL; 1755 } 1756 1757 oldfds = (cm->cmsg_len - CMSG_LEN(0)) / sizeof(int); 1758 1759 /* 1760 * Now replace the integer FDs with pointers to 1761 * the associated global file table entry.. 1762 * Allocate a bigger buffer as necessary. But if an cluster is not 1763 * enough, return E2BIG. 1764 */ 1765 newlen = CMSG_LEN(oldfds * sizeof(struct file *)); 1766 if (newlen > MCLBYTES) 1767 return E2BIG; 1768 if (newlen - control->m_len > M_TRAILINGSPACE(control)) { 1769 if (control->m_flags & M_EXT) 1770 return E2BIG; 1771 MCLGET(control, M_WAITOK); 1772 1773 /* copy the data to the cluster */ 1774 memcpy(mtod(control, char *), cm, cm->cmsg_len); 1775 cm = mtod(control, struct cmsghdr *); 1776 } 1777 1778 lwkt_gettoken(&unp_rights_token); 1779 1780 fdescp = p->p_fd; 1781 spin_lock_shared(&fdescp->fd_spin); 1782 1783 /* 1784 * check that all the FDs passed in refer to legal OPEN files 1785 * If not, reject the entire operation. 1786 */ 1787 fdp = (int *)CMSG_DATA(cm); 1788 for (i = 0; i < oldfds; i++) { 1789 fd = *fdp++; 1790 if ((unsigned)fd >= fdescp->fd_nfiles || 1791 fdescp->fd_files[fd].fp == NULL) { 1792 error = EBADF; 1793 goto done; 1794 } 1795 if (fdescp->fd_files[fd].fp->f_type == DTYPE_KQUEUE) { 1796 error = EOPNOTSUPP; 1797 goto done; 1798 } 1799 } 1800 1801 /* 1802 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1803 * differs. 1804 */ 1805 cm->cmsg_len = newlen; 1806 control->m_len = CMSG_ALIGN(newlen); 1807 1808 /* 1809 * Transform the file descriptors into struct file pointers. 1810 * Since the sizeof(struct file *) is bigger than or equal to 1811 * the sizeof(int), we do it in reverse order so that the int 1812 * won't get trashed until we're done. 1813 */ 1814 fdp = (int *)CMSG_DATA(cm) + oldfds - 1; 1815 rp = (struct file **)CMSG_DATA(cm) + oldfds - 1; 1816 for (i = 0; i < oldfds; i++) { 1817 fp = fdescp->fd_files[*fdp--].fp; 1818 *rp-- = fp; 1819 fhold(fp); 1820 unp_add_right(fp); 1821 } 1822 error = 0; 1823 done: 1824 spin_unlock_shared(&fdescp->fd_spin); 1825 lwkt_reltoken(&unp_rights_token); 1826 return error; 1827 } 1828 1829 #ifdef UNP_GC_ALLFILES 1830 1831 /* 1832 * Garbage collect in-transit file descriptors that get lost due to 1833 * loops (i.e. when a socket is sent to another process over itself, 1834 * and more complex situations). 1835 * 1836 * NOT MPSAFE - TODO socket flush code and maybe fdrop. Rest is MPSAFE. 1837 */ 1838 1839 struct unp_gc_info { 1840 struct file **extra_ref; 1841 struct file *locked_fp; 1842 int defer; 1843 int index; 1844 int maxindex; 1845 }; 1846 1847 static void 1848 unp_gc(void *arg __unused, int pending __unused) 1849 { 1850 struct unp_gc_info info; 1851 struct file **fpp; 1852 int i; 1853 1854 lwkt_gettoken(&unp_rights_token); 1855 1856 /* 1857 * Before going through all this, set all FDs to be NOT defered 1858 * and NOT externally accessible (not marked). During the scan 1859 * a fd can be marked externally accessible but we may or may not 1860 * be able to immediately process it (controlled by FDEFER). 1861 * 1862 * If we loop sleep a bit. The complexity of the topology can cause 1863 * multiple loops. Also failure to acquire the socket's so_rcv 1864 * token can cause us to loop. 1865 */ 1866 allfiles_scan_exclusive(unp_gc_clearmarks, NULL); 1867 do { 1868 info.defer = 0; 1869 allfiles_scan_exclusive(unp_gc_checkmarks, &info); 1870 if (info.defer) 1871 tsleep(&info, 0, "gcagain", 1); 1872 } while (info.defer); 1873 1874 /* 1875 * We grab an extra reference to each of the file table entries 1876 * that are not otherwise accessible and then free the rights 1877 * that are stored in messages on them. 1878 * 1879 * The bug in the orginal code is a little tricky, so I'll describe 1880 * what's wrong with it here. 1881 * 1882 * It is incorrect to simply unp_discard each entry for f_msgcount 1883 * times -- consider the case of sockets A and B that contain 1884 * references to each other. On a last close of some other socket, 1885 * we trigger a gc since the number of outstanding rights (unp_rights) 1886 * is non-zero. If during the sweep phase the gc code unp_discards, 1887 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 1888 * results in the following chain. Closef calls soo_close, which 1889 * calls soclose. Soclose calls first (through the switch 1890 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1891 * returns because the previous instance had set unp_gcing, and 1892 * we return all the way back to soclose, which marks the socket 1893 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1894 * to free up the rights that are queued in messages on the socket A, 1895 * i.e., the reference on B. The sorflush calls via the dom_dispose 1896 * switch unp_dispose, which unp_scans with unp_discard. This second 1897 * instance of unp_discard just calls fdrop on B. 1898 * 1899 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1900 * which results in another fdrop on A. Unfortunately, A is already 1901 * being closed, and the descriptor has already been marked with 1902 * SS_NOFDREF, and soclose panics at this point. 1903 * 1904 * Here, we first take an extra reference to each inaccessible 1905 * descriptor. Then, we call sorflush ourself, since we know 1906 * it is a Unix domain socket anyhow. After we destroy all the 1907 * rights carried in messages, we do a last fdrop to get rid 1908 * of our extra reference. This is the last close, and the 1909 * unp_detach etc will shut down the socket. 1910 * 1911 * 91/09/19, bsy@cs.cmu.edu 1912 */ 1913 info.extra_ref = kmalloc(256 * sizeof(struct file *), M_FILE, M_WAITOK); 1914 info.maxindex = 256; 1915 1916 do { 1917 /* 1918 * Look for matches 1919 */ 1920 info.index = 0; 1921 allfiles_scan_exclusive(unp_gc_checkrefs, &info); 1922 1923 /* 1924 * For each FD on our hit list, do the following two things 1925 */ 1926 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) { 1927 struct file *tfp = *fpp; 1928 if (tfp->f_type == DTYPE_SOCKET && tfp->f_data != NULL) 1929 sorflush((struct socket *)(tfp->f_data)); 1930 } 1931 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) 1932 fdrop(*fpp); 1933 } while (info.index == info.maxindex); 1934 1935 kfree((caddr_t)info.extra_ref, M_FILE); 1936 1937 lwkt_reltoken(&unp_rights_token); 1938 } 1939 1940 /* 1941 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1942 */ 1943 static int 1944 unp_gc_checkrefs(struct file *fp, void *data) 1945 { 1946 struct unp_gc_info *info = data; 1947 1948 if (fp->f_count == 0) 1949 return(0); 1950 if (info->index == info->maxindex) 1951 return(-1); 1952 1953 /* 1954 * If all refs are from msgs, and it's not marked accessible 1955 * then it must be referenced from some unreachable cycle 1956 * of (shut-down) FDs, so include it in our 1957 * list of FDs to remove 1958 */ 1959 if (fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) { 1960 info->extra_ref[info->index++] = fp; 1961 fhold(fp); 1962 } 1963 return(0); 1964 } 1965 1966 /* 1967 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1968 */ 1969 static int 1970 unp_gc_clearmarks(struct file *fp, void *data __unused) 1971 { 1972 atomic_clear_int(&fp->f_flag, FMARK | FDEFER); 1973 return(0); 1974 } 1975 1976 /* 1977 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1978 */ 1979 static int 1980 unp_gc_checkmarks(struct file *fp, void *data) 1981 { 1982 struct unp_gc_info *info = data; 1983 struct socket *so; 1984 1985 /* 1986 * If the file is not open, skip it. Make sure it isn't marked 1987 * defered or we could loop forever, in case we somehow race 1988 * something. 1989 */ 1990 if (fp->f_count == 0) { 1991 if (fp->f_flag & FDEFER) 1992 atomic_clear_int(&fp->f_flag, FDEFER); 1993 return(0); 1994 } 1995 /* 1996 * If we already marked it as 'defer' in a 1997 * previous pass, then try process it this time 1998 * and un-mark it 1999 */ 2000 if (fp->f_flag & FDEFER) { 2001 atomic_clear_int(&fp->f_flag, FDEFER); 2002 } else { 2003 /* 2004 * if it's not defered, then check if it's 2005 * already marked.. if so skip it 2006 */ 2007 if (fp->f_flag & FMARK) 2008 return(0); 2009 /* 2010 * If all references are from messages 2011 * in transit, then skip it. it's not 2012 * externally accessible. 2013 */ 2014 if (fp->f_count == fp->f_msgcount) 2015 return(0); 2016 /* 2017 * If it got this far then it must be 2018 * externally accessible. 2019 */ 2020 atomic_set_int(&fp->f_flag, FMARK); 2021 } 2022 2023 /* 2024 * either it was defered, or it is externally 2025 * accessible and not already marked so. 2026 * Now check if it is possibly one of OUR sockets. 2027 */ 2028 if (fp->f_type != DTYPE_SOCKET || 2029 (so = (struct socket *)fp->f_data) == NULL) { 2030 return(0); 2031 } 2032 if (so->so_proto->pr_domain != &localdomain || 2033 !(so->so_proto->pr_flags & PR_RIGHTS)) { 2034 return(0); 2035 } 2036 2037 /* 2038 * So, Ok, it's one of our sockets and it IS externally accessible 2039 * (or was defered). Now we look to see if we hold any file 2040 * descriptors in its message buffers. Follow those links and mark 2041 * them as accessible too. 2042 * 2043 * We are holding multiple spinlocks here, if we cannot get the 2044 * token non-blocking defer until the next loop. 2045 */ 2046 info->locked_fp = fp; 2047 if (lwkt_trytoken(&so->so_rcv.ssb_token)) { 2048 unp_scan(so->so_rcv.ssb_mb, unp_mark, info); 2049 lwkt_reltoken(&so->so_rcv.ssb_token); 2050 } else { 2051 atomic_set_int(&fp->f_flag, FDEFER); 2052 ++info->defer; 2053 } 2054 return (0); 2055 } 2056 2057 /* 2058 * Mark visibility. info->defer is recalculated on every pass. 2059 */ 2060 static void 2061 unp_mark(struct file *fp, void *data) 2062 { 2063 struct unp_gc_info *info = data; 2064 2065 if ((fp->f_flag & FMARK) == 0) { 2066 ++info->defer; 2067 atomic_set_int(&fp->f_flag, FMARK | FDEFER); 2068 } else if (fp->f_flag & FDEFER) { 2069 ++info->defer; 2070 } 2071 } 2072 2073 #else /* !UNP_GC_ALLFILES */ 2074 2075 /* 2076 * They are thread local and do not require explicit synchronization. 2077 */ 2078 static int unp_marked; 2079 static int unp_unreachable; 2080 2081 static void 2082 unp_accessable(struct file *fp, void *data __unused) 2083 { 2084 struct unpcb *unp; 2085 2086 if ((unp = unp_fp2unpcb(fp)) == NULL) 2087 return; 2088 if (unp->unp_gcflags & UNPGC_REF) 2089 return; 2090 unp->unp_gcflags &= ~UNPGC_DEAD; 2091 unp->unp_gcflags |= UNPGC_REF; 2092 unp_marked++; 2093 } 2094 2095 static void 2096 unp_gc_process(struct unpcb *unp) 2097 { 2098 struct file *fp; 2099 2100 /* Already processed. */ 2101 if (unp->unp_gcflags & UNPGC_SCANNED) 2102 return; 2103 fp = unp->unp_fp; 2104 2105 /* 2106 * Check for a socket potentially in a cycle. It must be in a 2107 * queue as indicated by msgcount, and this must equal the file 2108 * reference count. Note that when msgcount is 0 the file is NULL. 2109 */ 2110 if ((unp->unp_gcflags & UNPGC_REF) == 0 && fp && 2111 unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) { 2112 unp->unp_gcflags |= UNPGC_DEAD; 2113 unp_unreachable++; 2114 return; 2115 } 2116 2117 /* 2118 * Mark all sockets we reference with RIGHTS. 2119 */ 2120 if (UNP_ISATTACHED(unp)) { 2121 struct signalsockbuf *ssb = &unp->unp_socket->so_rcv; 2122 2123 unp_reference(unp); 2124 lwkt_gettoken(&ssb->ssb_token); 2125 /* 2126 * unp_token would be temporarily dropped, if getting 2127 * so_rcv token blocks, so we need to check unp state 2128 * here again. 2129 */ 2130 if (UNP_ISATTACHED(unp)) 2131 unp_scan(ssb->ssb_mb, unp_accessable, NULL); 2132 lwkt_reltoken(&ssb->ssb_token); 2133 unp->unp_gcflags |= UNPGC_SCANNED; 2134 unp_free(unp); 2135 } else { 2136 unp->unp_gcflags |= UNPGC_SCANNED; 2137 } 2138 } 2139 2140 static void 2141 unp_gc(void *arg __unused, int pending __unused) 2142 { 2143 struct unp_global_head *head; 2144 int h, filemax, fileidx, filetot; 2145 struct file **unref; 2146 struct unpcb *unp; 2147 2148 lwkt_gettoken(&unp_rights_token); 2149 lwkt_gettoken(&unp_token); 2150 2151 /* 2152 * First clear all gc flags from previous runs. 2153 */ 2154 for (h = 0; unp_heads[h] != NULL; ++h) { 2155 /* 2156 * NOTE: This loop does not block, so it is safe 2157 * to use TAILQ_FOREACH here. 2158 */ 2159 head = unp_heads[h]; 2160 TAILQ_FOREACH(unp, &head->list, unp_link) 2161 unp->unp_gcflags = 0; 2162 } 2163 2164 /* 2165 * Scan marking all reachable sockets with UNPGC_REF. Once a socket 2166 * is reachable all of the sockets it references are reachable. 2167 * Stop the scan once we do a complete loop without discovering 2168 * a new reachable socket. 2169 */ 2170 do { 2171 unp_unreachable = 0; 2172 unp_marked = 0; 2173 for (h = 0; unp_heads[h] != NULL; ++h) { 2174 head = unp_heads[h]; 2175 TAILQ_INSERT_HEAD(&head->list, unp_gc_marker, unp_link); 2176 while ((unp = TAILQ_NEXT(unp_gc_marker, unp_link)) 2177 != NULL) { 2178 TAILQ_REMOVE(&head->list, unp_gc_marker, 2179 unp_link); 2180 TAILQ_INSERT_AFTER(&head->list, unp, 2181 unp_gc_marker, unp_link); 2182 2183 if (unp->unp_flags & UNP_MARKER) 2184 continue; 2185 unp_gc_process(unp); 2186 } 2187 TAILQ_REMOVE(&head->list, unp_gc_marker, unp_link); 2188 } 2189 } while (unp_marked); 2190 2191 if (unp_unreachable == 0) 2192 goto done; 2193 2194 /* 2195 * We grab an extra reference to each of the file table entries 2196 * that are not otherwise accessible and then free the rights 2197 * that are stored in messages on them. 2198 * 2199 * The bug in the orginal code is a little tricky, so I'll describe 2200 * what's wrong with it here. 2201 * 2202 * It is incorrect to simply unp_discard each entry for f_msgcount 2203 * times -- consider the case of sockets A and B that contain 2204 * references to each other. On a last close of some other socket, 2205 * we trigger a gc since the number of outstanding rights (unp_rights) 2206 * is non-zero. If during the sweep phase the gc code unp_discards, 2207 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 2208 * results in the following chain. Closef calls soo_close, which 2209 * calls soclose. Soclose calls first (through the switch 2210 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2211 * returns because the previous instance had set unp_gcing, and 2212 * we return all the way back to soclose, which marks the socket 2213 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 2214 * to free up the rights that are queued in messages on the socket A, 2215 * i.e., the reference on B. The sorflush calls via the dom_dispose 2216 * switch unp_dispose, which unp_scans with unp_discard. This second 2217 * instance of unp_discard just calls fdrop on B. 2218 * 2219 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2220 * which results in another fdrop on A. Unfortunately, A is already 2221 * being closed, and the descriptor has already been marked with 2222 * SS_NOFDREF, and soclose panics at this point. 2223 * 2224 * Here, we first take an extra reference to each inaccessible 2225 * descriptor. Then, we call sorflush ourself, since we know 2226 * it is a Unix domain socket anyhow. After we destroy all the 2227 * rights carried in messages, we do a last fdrop to get rid 2228 * of our extra reference. This is the last close, and the 2229 * unp_detach etc will shut down the socket. 2230 * 2231 * 91/09/19, bsy@cs.cmu.edu 2232 */ 2233 2234 filemax = unp_unreachable; 2235 if (filemax > UNP_GCFILE_MAX) 2236 filemax = UNP_GCFILE_MAX; 2237 unref = kmalloc(filemax * sizeof(struct file *), M_TEMP, M_WAITOK); 2238 2239 filetot = 0; 2240 do { 2241 int i; 2242 2243 /* 2244 * Iterate looking for sockets which have been specifically 2245 * marked as as unreachable and store them locally. 2246 */ 2247 fileidx = 0; 2248 for (h = 0; unp_heads[h] != NULL; ++h) { 2249 /* 2250 * NOTE: This loop does not block, so it is safe 2251 * to use TAILQ_FOREACH here. 2252 */ 2253 head = unp_heads[h]; 2254 TAILQ_FOREACH(unp, &head->list, unp_link) { 2255 struct file *fp; 2256 2257 if ((unp->unp_gcflags & UNPGC_DEAD) == 0) 2258 continue; 2259 unp->unp_gcflags &= ~UNPGC_DEAD; 2260 2261 fp = unp->unp_fp; 2262 if (unp->unp_msgcount == 0 || fp == NULL || 2263 fp->f_count != unp->unp_msgcount) 2264 continue; 2265 fhold(fp); 2266 2267 KASSERT(fileidx < filemax, 2268 ("invalid fileidx %d, filemax %d", 2269 fileidx, filemax)); 2270 unref[fileidx++] = fp; 2271 2272 KASSERT(filetot < unp_unreachable, 2273 ("invalid filetot %d and " 2274 "unp_unreachable %d", 2275 filetot, unp_unreachable)); 2276 ++filetot; 2277 2278 if (fileidx == filemax || 2279 filetot == unp_unreachable) 2280 goto dogc; 2281 } 2282 } 2283 dogc: 2284 /* 2285 * For each Unix domain socket on our hit list, do the 2286 * following two things. 2287 */ 2288 for (i = 0; i < fileidx; ++i) 2289 sorflush(unref[i]->f_data); 2290 for (i = 0; i < fileidx; ++i) 2291 fdrop(unref[i]); 2292 } while (fileidx == filemax && filetot < unp_unreachable); 2293 kfree(unref, M_TEMP); 2294 done: 2295 lwkt_reltoken(&unp_token); 2296 lwkt_reltoken(&unp_rights_token); 2297 } 2298 2299 #endif /* UNP_GC_ALLFILES */ 2300 2301 /* 2302 * Dispose of the fp's stored in a mbuf. 2303 * 2304 * The dds loop can cause additional fps to be entered onto the 2305 * list while it is running, flattening out the operation and avoiding 2306 * a deep kernel stack recursion. 2307 */ 2308 void 2309 unp_dispose(struct mbuf *m) 2310 { 2311 lwkt_gettoken(&unp_rights_token); 2312 if (m) 2313 unp_scan(m, unp_discard, NULL); 2314 lwkt_reltoken(&unp_rights_token); 2315 } 2316 2317 static int 2318 unp_listen(struct unpcb *unp, struct thread *td) 2319 { 2320 struct proc *p = td->td_proc; 2321 2322 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2323 UNP_ASSERT_TOKEN_HELD(unp); 2324 2325 KKASSERT(p); 2326 cru2x(p->p_ucred, &unp->unp_peercred); 2327 unp_setflags(unp, UNP_HAVEPCCACHED); 2328 return (0); 2329 } 2330 2331 static void 2332 unp_scan(struct mbuf *m0, void (*op)(struct file *, void *), void *data) 2333 { 2334 struct mbuf *m; 2335 struct file **rp; 2336 struct cmsghdr *cm; 2337 int i; 2338 int qfds; 2339 2340 while (m0) { 2341 for (m = m0; m; m = m->m_next) { 2342 if (m->m_type == MT_CONTROL && 2343 m->m_len >= sizeof(*cm)) { 2344 cm = mtod(m, struct cmsghdr *); 2345 if (cm->cmsg_level != SOL_SOCKET || 2346 cm->cmsg_type != SCM_RIGHTS) 2347 continue; 2348 qfds = (cm->cmsg_len - CMSG_LEN(0)) / 2349 sizeof(void *); 2350 rp = (struct file **)CMSG_DATA(cm); 2351 for (i = 0; i < qfds; i++) 2352 (*op)(*rp++, data); 2353 break; /* XXX, but saves time */ 2354 } 2355 } 2356 m0 = m0->m_nextpkt; 2357 } 2358 } 2359 2360 /* 2361 * Discard a fp previously held in a unix domain socket mbuf. To 2362 * avoid blowing out the kernel stack due to contrived chain-reactions 2363 * we may have to defer the operation to a dedicated taskqueue. 2364 * 2365 * Caller holds unp_rights_token. 2366 */ 2367 static void 2368 unp_discard(struct file *fp, void *data __unused) 2369 { 2370 unp_del_right(fp); 2371 if (unp_fp2unpcb(fp) != NULL) { 2372 struct unp_defdiscard *d; 2373 2374 /* 2375 * This fp is a Unix domain socket itself and fdrop() 2376 * it here directly may cause deep unp_discard() 2377 * recursion, so the fdrop() is defered to the 2378 * dedicated taskqueue. 2379 */ 2380 d = kmalloc(sizeof(*d), M_UNPCB, M_WAITOK); 2381 d->fp = fp; 2382 2383 spin_lock(&unp_defdiscard_spin); 2384 SLIST_INSERT_HEAD(&unp_defdiscard_head, d, next); 2385 spin_unlock(&unp_defdiscard_spin); 2386 2387 taskqueue_enqueue(unp_taskqueue, &unp_defdiscard_task); 2388 } else { 2389 /* This fp is not a Unix domain socket */ 2390 fdrop(fp); 2391 } 2392 } 2393 2394 /* 2395 * NOTE: 2396 * unp_token must be held before calling this function to avoid name 2397 * resolution and v_socket accessing races, especially racing against 2398 * the unp_detach(). 2399 * 2400 * NOTE: 2401 * For anyone caring about unconnected Unix domain socket sending 2402 * performance, other approach could be taken... 2403 */ 2404 static int 2405 unp_find_lockref(struct sockaddr *nam, struct thread *td, short type, 2406 struct unpcb **unp_ret) 2407 { 2408 struct proc *p = td->td_proc; 2409 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 2410 struct vnode *vp = NULL; 2411 struct socket *so; 2412 struct unpcb *unp; 2413 int error, len; 2414 struct nlookupdata nd; 2415 char buf[SOCK_MAXADDRLEN]; 2416 2417 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2418 2419 *unp_ret = NULL; 2420 2421 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 2422 if (len <= 0) { 2423 error = EINVAL; 2424 goto failed; 2425 } 2426 strncpy(buf, soun->sun_path, len); 2427 buf[len] = 0; 2428 2429 error = nlookup_init(&nd, buf, UIO_SYSSPACE, NLC_FOLLOW); 2430 if (error == 0) 2431 error = nlookup(&nd); 2432 if (error == 0) 2433 error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp); 2434 nlookup_done(&nd); 2435 if (error) { 2436 vp = NULL; 2437 goto failed; 2438 } 2439 2440 if (vp->v_type != VSOCK) { 2441 error = ENOTSOCK; 2442 goto failed; 2443 } 2444 error = VOP_EACCESS(vp, VWRITE, p->p_ucred); 2445 if (error) 2446 goto failed; 2447 so = vp->v_socket; 2448 if (so == NULL) { 2449 error = ECONNREFUSED; 2450 goto failed; 2451 } 2452 if (so->so_type != type) { 2453 error = EPROTOTYPE; 2454 goto failed; 2455 } 2456 2457 /* Lock this unp. */ 2458 unp = unp_getsocktoken(so); 2459 if (!UNP_ISATTACHED(unp)) { 2460 unp_reltoken(unp); 2461 error = ECONNREFUSED; 2462 goto failed; 2463 } 2464 /* And keep this unp referenced. */ 2465 unp_reference(unp); 2466 2467 /* Done! */ 2468 *unp_ret = unp; 2469 error = 0; 2470 failed: 2471 if (vp != NULL) 2472 vput(vp); 2473 return error; 2474 } 2475 2476 static int 2477 unp_connect_pair(struct unpcb *unp, struct unpcb *unp2) 2478 { 2479 struct socket *so = unp->unp_socket; 2480 struct socket *so2 = unp2->unp_socket; 2481 2482 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2483 UNP_ASSERT_TOKEN_HELD(unp); 2484 UNP_ASSERT_TOKEN_HELD(unp2); 2485 2486 KASSERT(so->so_type == so2->so_type, 2487 ("socket type mismatch, so %d, so2 %d", so->so_type, so2->so_type)); 2488 2489 if (!UNP_ISATTACHED(unp)) 2490 return EINVAL; 2491 if (!UNP_ISATTACHED(unp2)) 2492 return ECONNREFUSED; 2493 2494 KASSERT(unp->unp_conn == NULL, ("unp is already connected")); 2495 unp->unp_conn = unp2; 2496 2497 switch (so->so_type) { 2498 case SOCK_DGRAM: 2499 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 2500 soisconnected(so); 2501 break; 2502 2503 case SOCK_STREAM: 2504 case SOCK_SEQPACKET: 2505 KASSERT(unp2->unp_conn == NULL, ("unp2 is already connected")); 2506 unp2->unp_conn = unp; 2507 soisconnected(so); 2508 soisconnected(so2); 2509 break; 2510 2511 default: 2512 panic("unp_connect_pair: unknown socket type %d", so->so_type); 2513 } 2514 return 0; 2515 } 2516 2517 static void 2518 unp_drop(struct unpcb *unp, int error) 2519 { 2520 struct unp_global_head *head; 2521 struct unpcb *unp2; 2522 2523 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2524 UNP_ASSERT_TOKEN_HELD(unp); 2525 2526 KASSERT((unp->unp_flags & (UNP_DETACHED | UNP_DROPPED)) == 0, 2527 ("unp is dropped")); 2528 2529 /* Mark this unp as detached. */ 2530 unp_setflags(unp, UNP_DETACHED); 2531 2532 /* Remove this unp from the global unp list. */ 2533 head = unp_globalhead(unp->unp_socket->so_type); 2534 KASSERT(head->count > 0, ("invalid unp count")); 2535 TAILQ_REMOVE(&head->list, unp, unp_link); 2536 head->count--; 2537 2538 /* Disconnect all. */ 2539 unp_disconnect(unp, error); 2540 while ((unp2 = LIST_FIRST(&unp->unp_refs)) != NULL) { 2541 lwkt_getpooltoken(unp2); 2542 unp_disconnect(unp2, ECONNRESET); 2543 lwkt_relpooltoken(unp2); 2544 } 2545 unp_setflags(unp, UNP_DROPPED); 2546 2547 /* Try freeing this unp. */ 2548 unp_free(unp); 2549 } 2550 2551 static void 2552 unp_defdiscard_taskfunc(void *arg __unused, int pending __unused) 2553 { 2554 struct unp_defdiscard *d; 2555 2556 spin_lock(&unp_defdiscard_spin); 2557 while ((d = SLIST_FIRST(&unp_defdiscard_head)) != NULL) { 2558 SLIST_REMOVE_HEAD(&unp_defdiscard_head, next); 2559 spin_unlock(&unp_defdiscard_spin); 2560 2561 fdrop(d->fp); 2562 kfree(d, M_UNPCB); 2563 2564 spin_lock(&unp_defdiscard_spin); 2565 } 2566 spin_unlock(&unp_defdiscard_spin); 2567 } 2568