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 lwkt_replymsg(&msg->lmsg, error); 435 } 436 437 /* control is EOPNOTSUPP */ 438 439 static void 440 uipc_detach(netmsg_t msg) 441 { 442 struct unpcb *unp; 443 int error; 444 445 lwkt_gettoken(&unp_token); 446 unp = unp_getsocktoken(msg->base.nm_so); 447 448 if (UNP_ISATTACHED(unp)) { 449 unp_drop(unp, 0); 450 error = 0; 451 } else { 452 error = EINVAL; 453 } 454 455 unp_reltoken(unp); 456 lwkt_reltoken(&unp_token); 457 458 lwkt_replymsg(&msg->lmsg, error); 459 } 460 461 static void 462 uipc_disconnect(netmsg_t msg) 463 { 464 struct unpcb *unp; 465 int error; 466 467 lwkt_gettoken(&unp_token); 468 unp = unp_getsocktoken(msg->base.nm_so); 469 470 if (UNP_ISATTACHED(unp)) { 471 unp_disconnect(unp, 0); 472 error = 0; 473 } else { 474 error = EINVAL; 475 } 476 477 unp_reltoken(unp); 478 lwkt_reltoken(&unp_token); 479 480 lwkt_replymsg(&msg->lmsg, error); 481 } 482 483 static void 484 uipc_listen(netmsg_t msg) 485 { 486 struct unpcb *unp; 487 int error; 488 489 lwkt_gettoken(&unp_token); 490 unp = unp_getsocktoken(msg->base.nm_so); 491 492 if (!UNP_ISATTACHED(unp) || unp->unp_vnode == NULL) 493 error = EINVAL; 494 else 495 error = unp_listen(unp, msg->listen.nm_td); 496 497 unp_reltoken(unp); 498 lwkt_reltoken(&unp_token); 499 500 lwkt_replymsg(&msg->lmsg, error); 501 } 502 503 static void 504 uipc_peeraddr(netmsg_t msg) 505 { 506 struct unpcb *unp; 507 int error; 508 509 lwkt_gettoken(&unp_token); 510 unp = unp_getsocktoken(msg->base.nm_so); 511 512 if (!UNP_ISATTACHED(unp)) { 513 error = EINVAL; 514 } else if (unp->unp_conn && unp->unp_conn->unp_addr) { 515 struct unpcb *unp2 = unp->unp_conn; 516 517 unp_reference(unp2); 518 *msg->peeraddr.nm_nam = dup_sockaddr( 519 (struct sockaddr *)unp2->unp_addr); 520 unp_free(unp2); 521 error = 0; 522 } else { 523 /* 524 * XXX: It seems that this test always fails even when 525 * connection is established. So, this else clause is 526 * added as workaround to return PF_LOCAL sockaddr. 527 */ 528 *msg->peeraddr.nm_nam = dup_sockaddr(&sun_noname); 529 error = 0; 530 } 531 532 unp_reltoken(unp); 533 lwkt_reltoken(&unp_token); 534 535 lwkt_replymsg(&msg->lmsg, error); 536 } 537 538 static void 539 uipc_rcvd(netmsg_t msg) 540 { 541 struct unpcb *unp, *unp2; 542 struct socket *so; 543 struct socket *so2; 544 int error; 545 546 /* 547 * so_pcb is only modified with both the global and the unp 548 * pool token held. 549 */ 550 so = msg->base.nm_so; 551 unp = unp_getsocktoken(so); 552 553 if (!UNP_ISATTACHED(unp)) { 554 error = EINVAL; 555 goto done; 556 } 557 558 switch (so->so_type) { 559 case SOCK_DGRAM: 560 panic("uipc_rcvd DGRAM?"); 561 /*NOTREACHED*/ 562 case SOCK_STREAM: 563 case SOCK_SEQPACKET: 564 if (unp->unp_conn == NULL) 565 break; 566 unp2 = unp->unp_conn; /* protected by pool token */ 567 568 /* 569 * Because we are transfering mbufs directly to the 570 * peer socket we have to use SSB_STOP on the sender 571 * to prevent it from building up infinite mbufs. 572 * 573 * As in several places in this module w ehave to ref unp2 574 * to ensure that it does not get ripped out from under us 575 * if we block on the so2 token or in sowwakeup(). 576 */ 577 so2 = unp2->unp_socket; 578 unp_reference(unp2); 579 lwkt_gettoken(&so2->so_rcv.ssb_token); 580 if (so->so_rcv.ssb_cc < so2->so_snd.ssb_hiwat && 581 so->so_rcv.ssb_mbcnt < so2->so_snd.ssb_mbmax 582 ) { 583 atomic_clear_int(&so2->so_snd.ssb_flags, SSB_STOP); 584 585 sowwakeup(so2); 586 } 587 lwkt_reltoken(&so2->so_rcv.ssb_token); 588 unp_free(unp2); 589 break; 590 default: 591 panic("uipc_rcvd unknown socktype"); 592 /*NOTREACHED*/ 593 } 594 error = 0; 595 done: 596 unp_reltoken(unp); 597 lwkt_replymsg(&msg->lmsg, error); 598 } 599 600 /* pru_rcvoob is EOPNOTSUPP */ 601 602 static void 603 uipc_send(netmsg_t msg) 604 { 605 struct unpcb *unp, *unp2; 606 struct socket *so; 607 struct socket *so2; 608 struct mbuf *control; 609 struct mbuf *m; 610 int error = 0; 611 612 so = msg->base.nm_so; 613 control = msg->send.nm_control; 614 m = msg->send.nm_m; 615 616 /* 617 * so_pcb is only modified with both the global and the unp 618 * pool token held. 619 */ 620 so = msg->base.nm_so; 621 unp = unp_getsocktoken(so); 622 623 if (!UNP_ISATTACHED(unp)) { 624 error = EINVAL; 625 goto release; 626 } 627 628 if (msg->send.nm_flags & PRUS_OOB) { 629 error = EOPNOTSUPP; 630 goto release; 631 } 632 633 wakeup_start_delayed(); 634 635 if (control && (error = unp_internalize(control, msg->send.nm_td))) 636 goto release; 637 638 switch (so->so_type) { 639 case SOCK_DGRAM: 640 { 641 struct sockaddr *from; 642 643 if (msg->send.nm_addr) { 644 if (unp->unp_conn) { 645 error = EISCONN; 646 break; 647 } 648 lwkt_gettoken(&unp_token); 649 error = unp_find_lockref(msg->send.nm_addr, 650 msg->send.nm_td, so->so_type, &unp2); 651 if (error) { 652 lwkt_reltoken(&unp_token); 653 break; 654 } 655 /* 656 * NOTE: 657 * unp2 is locked and referenced. 658 * 659 * We could unlock unp2 now, since it was checked 660 * and referenced. 661 */ 662 unp_reltoken(unp2); 663 lwkt_reltoken(&unp_token); 664 } else { 665 if (unp->unp_conn == NULL) { 666 error = ENOTCONN; 667 break; 668 } 669 unp2 = unp->unp_conn; 670 unp_reference(unp2); 671 } 672 /* NOTE: unp2 is referenced. */ 673 so2 = unp2->unp_socket; 674 675 /* 676 * Include creds if the receive side wants them, even if 677 * the send side did not send them. 678 */ 679 if (so2->so_options & SO_PASSCRED) { 680 struct mbuf **mp; 681 struct cmsghdr *cm; 682 struct cmsgcred cred; 683 struct mbuf *ncon; 684 685 mp = &control; 686 while ((ncon = *mp) != NULL) { 687 cm = mtod(ncon, struct cmsghdr *); 688 if (cm->cmsg_type == SCM_CREDS && 689 cm->cmsg_level == SOL_SOCKET) 690 break; 691 mp = &ncon->m_next; 692 } 693 if (ncon == NULL) { 694 ncon = sbcreatecontrol((caddr_t)&cred, 695 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) 1153 goto done; 1154 1155 VATTR_NULL(&vattr); 1156 vattr.va_type = VSOCK; 1157 vattr.va_mode = (ACCESSPERMS & ~p->p_fd->fd_cmask); 1158 error = VOP_NCREATE(&nd.nl_nch, nd.nl_dvp, &vp, nd.nl_cred, &vattr); 1159 if (error == 0) { 1160 if (unp->unp_vnode == NULL) { 1161 vp->v_socket = unp->unp_socket; 1162 unp->unp_vnode = vp; 1163 unp->unp_addr = (struct sockaddr_un *)dup_sockaddr(nam); 1164 vn_unlock(vp); 1165 } else { 1166 vput(vp); /* late race */ 1167 error = EINVAL; 1168 } 1169 } 1170 done: 1171 nlookup_done(&nd); 1172 return (error); 1173 } 1174 1175 static int 1176 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1177 { 1178 struct unpcb *unp, *unp2; 1179 int error, flags = 0; 1180 1181 lwkt_gettoken(&unp_token); 1182 1183 unp = unp_getsocktoken(so); 1184 if (!UNP_ISATTACHED(unp)) { 1185 error = EINVAL; 1186 goto failed; 1187 } 1188 1189 if ((unp->unp_flags & UNP_CONNECTING) || unp->unp_conn != NULL) { 1190 error = EISCONN; 1191 goto failed; 1192 } 1193 1194 flags = UNP_CONNECTING; 1195 unp_setflags(unp, flags); 1196 1197 error = unp_find_lockref(nam, td, so->so_type, &unp2); 1198 if (error) 1199 goto failed; 1200 /* 1201 * NOTE: 1202 * unp2 is locked and referenced. 1203 */ 1204 1205 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1206 struct socket *so2, *so3; 1207 struct unpcb *unp3; 1208 1209 so2 = unp2->unp_socket; 1210 if (!(so2->so_options & SO_ACCEPTCONN) || 1211 /* listen is not completed yet */ 1212 !(unp2->unp_flags & UNP_HAVEPCCACHED) || 1213 (so3 = sonewconn_faddr(so2, 0, NULL, 1214 TRUE /* keep ref */)) == NULL) { 1215 error = ECONNREFUSED; 1216 goto done; 1217 } 1218 /* so3 has a socket reference. */ 1219 1220 unp3 = unp_getsocktoken(so3); 1221 if (!UNP_ISATTACHED(unp3)) { 1222 unp_reltoken(unp3); 1223 /* 1224 * Already aborted; we only need to drop the 1225 * socket reference held by sonewconn_faddr(). 1226 */ 1227 sofree(so3); 1228 error = ECONNREFUSED; 1229 goto done; 1230 } 1231 unp_reference(unp3); 1232 /* 1233 * NOTE: 1234 * unp3 is locked and referenced. 1235 */ 1236 1237 /* 1238 * Release so3 socket reference held by sonewconn_faddr(). 1239 * Since we have referenced unp3, neither unp3 nor so3 will 1240 * be destroyed here. 1241 */ 1242 sofree(so3); 1243 1244 if (unp2->unp_addr != NULL) { 1245 unp3->unp_addr = (struct sockaddr_un *) 1246 dup_sockaddr((struct sockaddr *)unp2->unp_addr); 1247 } 1248 1249 /* 1250 * unp_peercred management: 1251 * 1252 * The connecter's (client's) credentials are copied 1253 * from its process structure at the time of connect() 1254 * (which is now). 1255 */ 1256 cru2x(td->td_proc->p_ucred, &unp3->unp_peercred); 1257 unp_setflags(unp3, UNP_HAVEPC); 1258 /* 1259 * The receiver's (server's) credentials are copied 1260 * from the unp_peercred member of socket on which the 1261 * former called listen(); unp_listen() cached that 1262 * process's credentials at that time so we can use 1263 * them now. 1264 */ 1265 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1266 ("unp_connect: listener without cached peercred")); 1267 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1268 sizeof(unp->unp_peercred)); 1269 unp_setflags(unp, UNP_HAVEPC); 1270 1271 error = unp_connect_pair(unp, unp3); 1272 if (error) 1273 soabort_direct(so3); 1274 1275 /* Done with unp3 */ 1276 unp_free(unp3); 1277 unp_reltoken(unp3); 1278 } else { 1279 error = unp_connect_pair(unp, unp2); 1280 } 1281 done: 1282 unp_free(unp2); 1283 unp_reltoken(unp2); 1284 failed: 1285 if (flags) 1286 unp_clrflags(unp, flags); 1287 unp_reltoken(unp); 1288 1289 lwkt_reltoken(&unp_token); 1290 return (error); 1291 } 1292 1293 /* 1294 * Connect two unix domain sockets together. 1295 * 1296 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1297 * pool token also be held. 1298 */ 1299 int 1300 unp_connect2(struct socket *so, struct socket *so2) 1301 { 1302 struct unpcb *unp, *unp2; 1303 int error; 1304 1305 lwkt_gettoken(&unp_token); 1306 if (so2->so_type != so->so_type) { 1307 lwkt_reltoken(&unp_token); 1308 return (EPROTOTYPE); 1309 } 1310 unp = unp_getsocktoken(so); 1311 unp2 = unp_getsocktoken(so2); 1312 1313 if (!UNP_ISATTACHED(unp)) { 1314 error = EINVAL; 1315 goto done; 1316 } 1317 if (!UNP_ISATTACHED(unp2)) { 1318 error = ECONNREFUSED; 1319 goto done; 1320 } 1321 1322 if (unp->unp_conn != NULL) { 1323 error = EISCONN; 1324 goto done; 1325 } 1326 if ((so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET) && 1327 unp2->unp_conn != NULL) { 1328 error = EISCONN; 1329 goto done; 1330 } 1331 1332 error = unp_connect_pair(unp, unp2); 1333 done: 1334 unp_reltoken(unp2); 1335 unp_reltoken(unp); 1336 lwkt_reltoken(&unp_token); 1337 return (error); 1338 } 1339 1340 /* 1341 * Disconnect a unix domain socket pair. 1342 * 1343 * NOTE: Semantics for any change to unp_conn requires that the per-unp 1344 * pool token also be held. 1345 */ 1346 static void 1347 unp_disconnect(struct unpcb *unp, int error) 1348 { 1349 struct socket *so = unp->unp_socket; 1350 struct unpcb *unp2; 1351 1352 ASSERT_LWKT_TOKEN_HELD(&unp_token); 1353 UNP_ASSERT_TOKEN_HELD(unp); 1354 1355 if (error) 1356 so->so_error = error; 1357 1358 while ((unp2 = unp->unp_conn) != NULL) { 1359 lwkt_getpooltoken(unp2); 1360 if (unp2 == unp->unp_conn) 1361 break; 1362 lwkt_relpooltoken(unp2); 1363 } 1364 if (unp2 == NULL) 1365 return; 1366 /* unp2 is locked. */ 1367 1368 KASSERT((unp2->unp_flags & UNP_DROPPED) == 0, ("unp2 was dropped")); 1369 1370 unp->unp_conn = NULL; 1371 1372 switch (so->so_type) { 1373 case SOCK_DGRAM: 1374 LIST_REMOVE(unp, unp_reflink); 1375 soclrstate(so, SS_ISCONNECTED); 1376 break; 1377 1378 case SOCK_STREAM: 1379 case SOCK_SEQPACKET: 1380 /* 1381 * Keep a reference before clearing the unp_conn 1382 * to avoid racing uipc_detach()/uipc_abort() in 1383 * other thread. 1384 */ 1385 unp_reference(unp2); 1386 KASSERT(unp2->unp_conn == unp, ("unp_conn mismatch")); 1387 unp2->unp_conn = NULL; 1388 1389 soisdisconnected(so); 1390 soisdisconnected(unp2->unp_socket); 1391 1392 unp_free(unp2); 1393 break; 1394 } 1395 1396 lwkt_relpooltoken(unp2); 1397 } 1398 1399 #ifdef notdef 1400 void 1401 unp_abort(struct unpcb *unp) 1402 { 1403 lwkt_gettoken(&unp_token); 1404 unp_free(unp); 1405 lwkt_reltoken(&unp_token); 1406 } 1407 #endif 1408 1409 static int 1410 prison_unpcb(struct thread *td, struct unpcb *unp) 1411 { 1412 struct proc *p; 1413 1414 if (td == NULL) 1415 return (0); 1416 if ((p = td->td_proc) == NULL) 1417 return (0); 1418 if (!p->p_ucred->cr_prison) 1419 return (0); 1420 if (p->p_fd->fd_rdir == unp->unp_rvnode) 1421 return (0); 1422 return (1); 1423 } 1424 1425 static int 1426 unp_pcblist(SYSCTL_HANDLER_ARGS) 1427 { 1428 struct unp_global_head *head = arg1; 1429 int error, i, n; 1430 struct unpcb *unp, *marker; 1431 1432 KKASSERT(curproc != NULL); 1433 1434 /* 1435 * The process of preparing the PCB list is too time-consuming and 1436 * resource-intensive to repeat twice on every request. 1437 */ 1438 if (req->oldptr == NULL) { 1439 n = head->count; 1440 req->oldidx = (n + n/8) * sizeof(struct xunpcb); 1441 return 0; 1442 } 1443 1444 if (req->newptr != NULL) 1445 return EPERM; 1446 1447 marker = kmalloc(sizeof(*marker), M_UNPCB, M_WAITOK | M_ZERO); 1448 marker->unp_flags |= UNP_MARKER; 1449 1450 lwkt_gettoken(&unp_token); 1451 1452 n = head->count; 1453 i = 0; 1454 error = 0; 1455 1456 TAILQ_INSERT_HEAD(&head->list, marker, unp_link); 1457 while ((unp = TAILQ_NEXT(marker, unp_link)) != NULL && i < n) { 1458 struct xunpcb xu; 1459 1460 TAILQ_REMOVE(&head->list, marker, unp_link); 1461 TAILQ_INSERT_AFTER(&head->list, unp, marker, unp_link); 1462 1463 if (unp->unp_flags & UNP_MARKER) 1464 continue; 1465 if (prison_unpcb(req->td, unp)) 1466 continue; 1467 1468 xu.xu_len = sizeof(xu); 1469 xu.xu_unpp = unp; 1470 1471 /* 1472 * NOTE: 1473 * unp->unp_addr and unp->unp_conn are protected by 1474 * unp_token. So if we want to get rid of unp_token 1475 * or reduce the coverage of unp_token, care must be 1476 * taken. 1477 */ 1478 if (unp->unp_addr) { 1479 bcopy(unp->unp_addr, &xu.xu_addr, 1480 unp->unp_addr->sun_len); 1481 } 1482 if (unp->unp_conn && unp->unp_conn->unp_addr) { 1483 bcopy(unp->unp_conn->unp_addr, 1484 &xu.xu_caddr, 1485 unp->unp_conn->unp_addr->sun_len); 1486 } 1487 bcopy(unp, &xu.xu_unp, sizeof(*unp)); 1488 sotoxsocket(unp->unp_socket, &xu.xu_socket); 1489 1490 /* NOTE: This could block and temporarily release unp_token */ 1491 error = SYSCTL_OUT(req, &xu, sizeof(xu)); 1492 if (error) 1493 break; 1494 ++i; 1495 } 1496 TAILQ_REMOVE(&head->list, marker, unp_link); 1497 1498 lwkt_reltoken(&unp_token); 1499 1500 kfree(marker, M_UNPCB); 1501 return error; 1502 } 1503 1504 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1505 &unp_dgram_head, 0, unp_pcblist, "S,xunpcb", 1506 "List of active local datagram sockets"); 1507 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1508 &unp_stream_head, 0, unp_pcblist, "S,xunpcb", 1509 "List of active local stream sockets"); 1510 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist, CTLFLAG_RD, 1511 &unp_seqpkt_head, 0, unp_pcblist, "S,xunpcb", 1512 "List of active local seqpacket sockets"); 1513 1514 static void 1515 unp_shutdown(struct unpcb *unp) 1516 { 1517 struct socket *so; 1518 1519 if ((unp->unp_socket->so_type == SOCK_STREAM || 1520 unp->unp_socket->so_type == SOCK_SEQPACKET) && 1521 unp->unp_conn != NULL && (so = unp->unp_conn->unp_socket)) { 1522 socantrcvmore(so); 1523 } 1524 } 1525 1526 #ifdef notdef 1527 void 1528 unp_drain(void) 1529 { 1530 lwkt_gettoken(&unp_token); 1531 lwkt_reltoken(&unp_token); 1532 } 1533 #endif 1534 1535 int 1536 unp_externalize(struct mbuf *rights, int flags) 1537 { 1538 struct thread *td = curthread; 1539 struct proc *p = td->td_proc; /* XXX */ 1540 struct lwp *lp = td->td_lwp; 1541 struct cmsghdr *cm = mtod(rights, struct cmsghdr *); 1542 int *fdp; 1543 int i; 1544 struct file **rp; 1545 struct file *fp; 1546 int newfds = (cm->cmsg_len - (CMSG_DATA(cm) - (u_char *)cm)) 1547 / sizeof(struct file *); 1548 int f; 1549 1550 lwkt_gettoken(&unp_rights_token); 1551 1552 /* 1553 * if the new FD's will not fit, then we free them all 1554 */ 1555 if (!fdavail(p, newfds)) { 1556 rp = (struct file **)CMSG_DATA(cm); 1557 for (i = 0; i < newfds; i++) { 1558 fp = *rp; 1559 /* 1560 * zero the pointer before calling unp_discard, 1561 * since it may end up in unp_gc().. 1562 */ 1563 *rp++ = NULL; 1564 unp_discard(fp, NULL); 1565 } 1566 lwkt_reltoken(&unp_rights_token); 1567 return (EMSGSIZE); 1568 } 1569 1570 /* 1571 * now change each pointer to an fd in the global table to 1572 * an integer that is the index to the local fd table entry 1573 * that we set up to point to the global one we are transferring. 1574 * Since the sizeof(struct file *) is bigger than or equal to 1575 * the sizeof(int), we do it in forward order. In that case, 1576 * an integer will always come in the same place or before its 1577 * corresponding struct file pointer. 1578 * 1579 * Hold revoke_token in 'shared' mode, so that we won't miss 1580 * the FREVOKED update on fps being externalized (fsetfd). 1581 */ 1582 lwkt_gettoken_shared(&revoke_token); 1583 fdp = (int *)CMSG_DATA(cm); 1584 rp = (struct file **)CMSG_DATA(cm); 1585 for (i = 0; i < newfds; i++) { 1586 if (fdalloc(p, 0, &f)) { 1587 int j; 1588 1589 /* 1590 * Previous fdavail() can't garantee 1591 * fdalloc() success due to SMP race. 1592 * Just clean up and return the same 1593 * error value as if fdavail() failed. 1594 */ 1595 lwkt_reltoken(&revoke_token); 1596 1597 /* Close externalized files */ 1598 for (j = 0; j < i; j++) 1599 kern_close(fdp[j]); 1600 /* Discard the rest of internal files */ 1601 for (; i < newfds; i++) 1602 unp_discard(rp[i], NULL); 1603 /* Wipe out the control message */ 1604 for (i = 0; i < newfds; i++) 1605 rp[i] = NULL; 1606 1607 lwkt_reltoken(&unp_rights_token); 1608 return (EMSGSIZE); 1609 } 1610 fp = rp[i]; 1611 unp_fp_externalize(lp, fp, f, flags); 1612 fdp[i] = f; 1613 } 1614 lwkt_reltoken(&revoke_token); 1615 1616 lwkt_reltoken(&unp_rights_token); 1617 1618 /* 1619 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1620 * differs. 1621 */ 1622 cm->cmsg_len = CMSG_LEN(newfds * sizeof(int)); 1623 rights->m_len = cm->cmsg_len; 1624 1625 return (0); 1626 } 1627 1628 static void 1629 unp_fp_externalize(struct lwp *lp, struct file *fp, int fd, int flags) 1630 { 1631 if (lp) { 1632 struct filedesc *fdp = lp->lwp_proc->p_fd; 1633 1634 KKASSERT(fd >= 0); 1635 if (fp->f_flag & FREVOKED) { 1636 struct file *fx; 1637 int error; 1638 1639 kprintf("Warning: revoked fp exiting unix socket\n"); 1640 error = falloc(lp, &fx, NULL); 1641 if (error == 0) { 1642 if (flags & MSG_CMSG_CLOEXEC) 1643 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1644 fsetfd(fdp, fx, fd); 1645 fdrop(fx); 1646 } else { 1647 fsetfd(fdp, NULL, fd); 1648 } 1649 } else { 1650 if (flags & MSG_CMSG_CLOEXEC) 1651 fdp->fd_files[fd].fileflags |= UF_EXCLOSE; 1652 fsetfd(fdp, fp, fd); 1653 } 1654 } 1655 unp_del_right(fp); 1656 fdrop(fp); 1657 } 1658 1659 void 1660 unp_init(void) 1661 { 1662 TAILQ_INIT(&unp_stream_head.list); 1663 TAILQ_INIT(&unp_dgram_head.list); 1664 TAILQ_INIT(&unp_seqpkt_head.list); 1665 1666 SLIST_INIT(&unp_defdiscard_head); 1667 spin_init(&unp_defdiscard_spin, "unpdisc"); 1668 TASK_INIT(&unp_defdiscard_task, 0, unp_defdiscard_taskfunc, NULL); 1669 1670 /* 1671 * This implies that only one gc can be in-progress at any 1672 * given moment. 1673 */ 1674 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1675 1676 unp_gc_marker = kmalloc(sizeof(*unp_gc_marker), M_UNPCB, 1677 M_WAITOK | M_ZERO); 1678 unp_gc_marker->unp_flags |= UNP_MARKER; 1679 1680 /* 1681 * Create taskqueue for defered discard, and stick it to 1682 * the last CPU. 1683 */ 1684 unp_taskqueue = taskqueue_create("unp_taskq", M_WAITOK, 1685 taskqueue_thread_enqueue, &unp_taskqueue); 1686 taskqueue_start_threads(&unp_taskqueue, 1, TDPRI_KERN_DAEMON, 1687 ncpus - 1, "unp taskq"); 1688 } 1689 1690 static int 1691 unp_internalize(struct mbuf *control, struct thread *td) 1692 { 1693 struct proc *p = td->td_proc; 1694 struct filedesc *fdescp; 1695 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1696 struct file **rp; 1697 struct file *fp; 1698 int i, fd, *fdp; 1699 struct cmsgcred *cmcred; 1700 int oldfds; 1701 u_int newlen; 1702 int error; 1703 1704 KKASSERT(p); 1705 1706 /* 1707 * Make sure the message is reasonable, and either CREDS or RIGHTS. 1708 * 1709 * NOTE: overall message length does not have to be aligned, but the 1710 * data start does. 1711 */ 1712 if ((cm->cmsg_type != SCM_RIGHTS && cm->cmsg_type != SCM_CREDS) || 1713 cm->cmsg_level != SOL_SOCKET || 1714 control->m_len < sizeof(*cm) || /* control too small */ 1715 cm->cmsg_len < sizeof(*cm) || /* cmsg_len too small */ 1716 cm->cmsg_len > control->m_len) { /* cmsg_len too big */ 1717 return EINVAL; 1718 } 1719 1720 /* 1721 * Fill in credential information. 1722 */ 1723 if (cm->cmsg_type == SCM_CREDS) { 1724 cmcred = (struct cmsgcred *)CMSG_DATA(cm); 1725 cmcred->cmcred_pid = p->p_pid; 1726 cmcred->cmcred_uid = p->p_ucred->cr_ruid; 1727 cmcred->cmcred_gid = p->p_ucred->cr_rgid; 1728 cmcred->cmcred_euid = p->p_ucred->cr_uid; 1729 cmcred->cmcred_ngroups = MIN(p->p_ucred->cr_ngroups, 1730 CMGROUP_MAX); 1731 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1732 cmcred->cmcred_groups[i] = p->p_ucred->cr_groups[i]; 1733 return 0; 1734 } 1735 1736 /* 1737 * cmsghdr may not be aligned, do not allow calculation(s) to 1738 * go negative. 1739 * 1740 * Data must be aligned but the data length does not have to be. 1741 * 1742 * If there are multiple headers (XXX not supported) then the 1743 * next header will be aligned after the end of the possibly 1744 * unaligned data. 1745 */ 1746 if (cm->cmsg_len < CMSG_LEN(0)) { 1747 return EINVAL; 1748 } 1749 1750 oldfds = (cm->cmsg_len - CMSG_LEN(0)) / sizeof(int); 1751 1752 /* 1753 * Now replace the integer FDs with pointers to 1754 * the associated global file table entry.. 1755 * Allocate a bigger buffer as necessary. But if an cluster is not 1756 * enough, return E2BIG. 1757 */ 1758 newlen = CMSG_LEN(oldfds * sizeof(struct file *)); 1759 if (newlen > MCLBYTES) 1760 return E2BIG; 1761 if (newlen - control->m_len > M_TRAILINGSPACE(control)) { 1762 if (control->m_flags & M_EXT) 1763 return E2BIG; 1764 MCLGET(control, M_WAITOK); 1765 if (!(control->m_flags & M_EXT)) 1766 return ENOBUFS; 1767 1768 /* copy the data to the cluster */ 1769 memcpy(mtod(control, char *), cm, cm->cmsg_len); 1770 cm = mtod(control, struct cmsghdr *); 1771 } 1772 1773 lwkt_gettoken(&unp_rights_token); 1774 1775 fdescp = p->p_fd; 1776 spin_lock_shared(&fdescp->fd_spin); 1777 1778 /* 1779 * check that all the FDs passed in refer to legal OPEN files 1780 * If not, reject the entire operation. 1781 */ 1782 fdp = (int *)CMSG_DATA(cm); 1783 for (i = 0; i < oldfds; i++) { 1784 fd = *fdp++; 1785 if ((unsigned)fd >= fdescp->fd_nfiles || 1786 fdescp->fd_files[fd].fp == NULL) { 1787 error = EBADF; 1788 goto done; 1789 } 1790 if (fdescp->fd_files[fd].fp->f_type == DTYPE_KQUEUE) { 1791 error = EOPNOTSUPP; 1792 goto done; 1793 } 1794 } 1795 1796 /* 1797 * Adjust length, in case sizeof(struct file *) and sizeof(int) 1798 * differs. 1799 */ 1800 cm->cmsg_len = newlen; 1801 control->m_len = CMSG_ALIGN(newlen); 1802 1803 /* 1804 * Transform the file descriptors into struct file pointers. 1805 * Since the sizeof(struct file *) is bigger than or equal to 1806 * the sizeof(int), we do it in reverse order so that the int 1807 * won't get trashed until we're done. 1808 */ 1809 fdp = (int *)CMSG_DATA(cm) + oldfds - 1; 1810 rp = (struct file **)CMSG_DATA(cm) + oldfds - 1; 1811 for (i = 0; i < oldfds; i++) { 1812 fp = fdescp->fd_files[*fdp--].fp; 1813 *rp-- = fp; 1814 fhold(fp); 1815 unp_add_right(fp); 1816 } 1817 error = 0; 1818 done: 1819 spin_unlock_shared(&fdescp->fd_spin); 1820 lwkt_reltoken(&unp_rights_token); 1821 return error; 1822 } 1823 1824 #ifdef UNP_GC_ALLFILES 1825 1826 /* 1827 * Garbage collect in-transit file descriptors that get lost due to 1828 * loops (i.e. when a socket is sent to another process over itself, 1829 * and more complex situations). 1830 * 1831 * NOT MPSAFE - TODO socket flush code and maybe fdrop. Rest is MPSAFE. 1832 */ 1833 1834 struct unp_gc_info { 1835 struct file **extra_ref; 1836 struct file *locked_fp; 1837 int defer; 1838 int index; 1839 int maxindex; 1840 }; 1841 1842 static void 1843 unp_gc(void *arg __unused, int pending __unused) 1844 { 1845 struct unp_gc_info info; 1846 struct file **fpp; 1847 int i; 1848 1849 lwkt_gettoken(&unp_rights_token); 1850 1851 /* 1852 * Before going through all this, set all FDs to be NOT defered 1853 * and NOT externally accessible (not marked). During the scan 1854 * a fd can be marked externally accessible but we may or may not 1855 * be able to immediately process it (controlled by FDEFER). 1856 * 1857 * If we loop sleep a bit. The complexity of the topology can cause 1858 * multiple loops. Also failure to acquire the socket's so_rcv 1859 * token can cause us to loop. 1860 */ 1861 allfiles_scan_exclusive(unp_gc_clearmarks, NULL); 1862 do { 1863 info.defer = 0; 1864 allfiles_scan_exclusive(unp_gc_checkmarks, &info); 1865 if (info.defer) 1866 tsleep(&info, 0, "gcagain", 1); 1867 } while (info.defer); 1868 1869 /* 1870 * We grab an extra reference to each of the file table entries 1871 * that are not otherwise accessible and then free the rights 1872 * that are stored in messages on them. 1873 * 1874 * The bug in the orginal code is a little tricky, so I'll describe 1875 * what's wrong with it here. 1876 * 1877 * It is incorrect to simply unp_discard each entry for f_msgcount 1878 * times -- consider the case of sockets A and B that contain 1879 * references to each other. On a last close of some other socket, 1880 * we trigger a gc since the number of outstanding rights (unp_rights) 1881 * is non-zero. If during the sweep phase the gc code unp_discards, 1882 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 1883 * results in the following chain. Closef calls soo_close, which 1884 * calls soclose. Soclose calls first (through the switch 1885 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1886 * returns because the previous instance had set unp_gcing, and 1887 * we return all the way back to soclose, which marks the socket 1888 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1889 * to free up the rights that are queued in messages on the socket A, 1890 * i.e., the reference on B. The sorflush calls via the dom_dispose 1891 * switch unp_dispose, which unp_scans with unp_discard. This second 1892 * instance of unp_discard just calls fdrop on B. 1893 * 1894 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1895 * which results in another fdrop on A. Unfortunately, A is already 1896 * being closed, and the descriptor has already been marked with 1897 * SS_NOFDREF, and soclose panics at this point. 1898 * 1899 * Here, we first take an extra reference to each inaccessible 1900 * descriptor. Then, we call sorflush ourself, since we know 1901 * it is a Unix domain socket anyhow. After we destroy all the 1902 * rights carried in messages, we do a last fdrop to get rid 1903 * of our extra reference. This is the last close, and the 1904 * unp_detach etc will shut down the socket. 1905 * 1906 * 91/09/19, bsy@cs.cmu.edu 1907 */ 1908 info.extra_ref = kmalloc(256 * sizeof(struct file *), M_FILE, M_WAITOK); 1909 info.maxindex = 256; 1910 1911 do { 1912 /* 1913 * Look for matches 1914 */ 1915 info.index = 0; 1916 allfiles_scan_exclusive(unp_gc_checkrefs, &info); 1917 1918 /* 1919 * For each FD on our hit list, do the following two things 1920 */ 1921 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) { 1922 struct file *tfp = *fpp; 1923 if (tfp->f_type == DTYPE_SOCKET && tfp->f_data != NULL) 1924 sorflush((struct socket *)(tfp->f_data)); 1925 } 1926 for (i = info.index, fpp = info.extra_ref; --i >= 0; ++fpp) 1927 fdrop(*fpp); 1928 } while (info.index == info.maxindex); 1929 1930 kfree((caddr_t)info.extra_ref, M_FILE); 1931 1932 lwkt_reltoken(&unp_rights_token); 1933 } 1934 1935 /* 1936 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1937 */ 1938 static int 1939 unp_gc_checkrefs(struct file *fp, void *data) 1940 { 1941 struct unp_gc_info *info = data; 1942 1943 if (fp->f_count == 0) 1944 return(0); 1945 if (info->index == info->maxindex) 1946 return(-1); 1947 1948 /* 1949 * If all refs are from msgs, and it's not marked accessible 1950 * then it must be referenced from some unreachable cycle 1951 * of (shut-down) FDs, so include it in our 1952 * list of FDs to remove 1953 */ 1954 if (fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) { 1955 info->extra_ref[info->index++] = fp; 1956 fhold(fp); 1957 } 1958 return(0); 1959 } 1960 1961 /* 1962 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1963 */ 1964 static int 1965 unp_gc_clearmarks(struct file *fp, void *data __unused) 1966 { 1967 atomic_clear_int(&fp->f_flag, FMARK | FDEFER); 1968 return(0); 1969 } 1970 1971 /* 1972 * MPSAFE - NOTE: filehead list and file pointer spinlocked on entry 1973 */ 1974 static int 1975 unp_gc_checkmarks(struct file *fp, void *data) 1976 { 1977 struct unp_gc_info *info = data; 1978 struct socket *so; 1979 1980 /* 1981 * If the file is not open, skip it. Make sure it isn't marked 1982 * defered or we could loop forever, in case we somehow race 1983 * something. 1984 */ 1985 if (fp->f_count == 0) { 1986 if (fp->f_flag & FDEFER) 1987 atomic_clear_int(&fp->f_flag, FDEFER); 1988 return(0); 1989 } 1990 /* 1991 * If we already marked it as 'defer' in a 1992 * previous pass, then try process it this time 1993 * and un-mark it 1994 */ 1995 if (fp->f_flag & FDEFER) { 1996 atomic_clear_int(&fp->f_flag, FDEFER); 1997 } else { 1998 /* 1999 * if it's not defered, then check if it's 2000 * already marked.. if so skip it 2001 */ 2002 if (fp->f_flag & FMARK) 2003 return(0); 2004 /* 2005 * If all references are from messages 2006 * in transit, then skip it. it's not 2007 * externally accessible. 2008 */ 2009 if (fp->f_count == fp->f_msgcount) 2010 return(0); 2011 /* 2012 * If it got this far then it must be 2013 * externally accessible. 2014 */ 2015 atomic_set_int(&fp->f_flag, FMARK); 2016 } 2017 2018 /* 2019 * either it was defered, or it is externally 2020 * accessible and not already marked so. 2021 * Now check if it is possibly one of OUR sockets. 2022 */ 2023 if (fp->f_type != DTYPE_SOCKET || 2024 (so = (struct socket *)fp->f_data) == NULL) { 2025 return(0); 2026 } 2027 if (so->so_proto->pr_domain != &localdomain || 2028 !(so->so_proto->pr_flags & PR_RIGHTS)) { 2029 return(0); 2030 } 2031 2032 /* 2033 * So, Ok, it's one of our sockets and it IS externally accessible 2034 * (or was defered). Now we look to see if we hold any file 2035 * descriptors in its message buffers. Follow those links and mark 2036 * them as accessible too. 2037 * 2038 * We are holding multiple spinlocks here, if we cannot get the 2039 * token non-blocking defer until the next loop. 2040 */ 2041 info->locked_fp = fp; 2042 if (lwkt_trytoken(&so->so_rcv.ssb_token)) { 2043 unp_scan(so->so_rcv.ssb_mb, unp_mark, info); 2044 lwkt_reltoken(&so->so_rcv.ssb_token); 2045 } else { 2046 atomic_set_int(&fp->f_flag, FDEFER); 2047 ++info->defer; 2048 } 2049 return (0); 2050 } 2051 2052 /* 2053 * Mark visibility. info->defer is recalculated on every pass. 2054 */ 2055 static void 2056 unp_mark(struct file *fp, void *data) 2057 { 2058 struct unp_gc_info *info = data; 2059 2060 if ((fp->f_flag & FMARK) == 0) { 2061 ++info->defer; 2062 atomic_set_int(&fp->f_flag, FMARK | FDEFER); 2063 } else if (fp->f_flag & FDEFER) { 2064 ++info->defer; 2065 } 2066 } 2067 2068 #else /* !UNP_GC_ALLFILES */ 2069 2070 /* 2071 * They are thread local and do not require explicit synchronization. 2072 */ 2073 static int unp_marked; 2074 static int unp_unreachable; 2075 2076 static void 2077 unp_accessable(struct file *fp, void *data __unused) 2078 { 2079 struct unpcb *unp; 2080 2081 if ((unp = unp_fp2unpcb(fp)) == NULL) 2082 return; 2083 if (unp->unp_gcflags & UNPGC_REF) 2084 return; 2085 unp->unp_gcflags &= ~UNPGC_DEAD; 2086 unp->unp_gcflags |= UNPGC_REF; 2087 unp_marked++; 2088 } 2089 2090 static void 2091 unp_gc_process(struct unpcb *unp) 2092 { 2093 struct file *fp; 2094 2095 /* Already processed. */ 2096 if (unp->unp_gcflags & UNPGC_SCANNED) 2097 return; 2098 fp = unp->unp_fp; 2099 2100 /* 2101 * Check for a socket potentially in a cycle. It must be in a 2102 * queue as indicated by msgcount, and this must equal the file 2103 * reference count. Note that when msgcount is 0 the file is NULL. 2104 */ 2105 if ((unp->unp_gcflags & UNPGC_REF) == 0 && fp && 2106 unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) { 2107 unp->unp_gcflags |= UNPGC_DEAD; 2108 unp_unreachable++; 2109 return; 2110 } 2111 2112 /* 2113 * Mark all sockets we reference with RIGHTS. 2114 */ 2115 if (UNP_ISATTACHED(unp)) { 2116 struct signalsockbuf *ssb = &unp->unp_socket->so_rcv; 2117 2118 unp_reference(unp); 2119 lwkt_gettoken(&ssb->ssb_token); 2120 /* 2121 * unp_token would be temporarily dropped, if getting 2122 * so_rcv token blocks, so we need to check unp state 2123 * here again. 2124 */ 2125 if (UNP_ISATTACHED(unp)) 2126 unp_scan(ssb->ssb_mb, unp_accessable, NULL); 2127 lwkt_reltoken(&ssb->ssb_token); 2128 unp->unp_gcflags |= UNPGC_SCANNED; 2129 unp_free(unp); 2130 } else { 2131 unp->unp_gcflags |= UNPGC_SCANNED; 2132 } 2133 } 2134 2135 static void 2136 unp_gc(void *arg __unused, int pending __unused) 2137 { 2138 struct unp_global_head *head; 2139 int h, filemax, fileidx, filetot; 2140 struct file **unref; 2141 struct unpcb *unp; 2142 2143 lwkt_gettoken(&unp_rights_token); 2144 lwkt_gettoken(&unp_token); 2145 2146 /* 2147 * First clear all gc flags from previous runs. 2148 */ 2149 for (h = 0; unp_heads[h] != NULL; ++h) { 2150 /* 2151 * NOTE: This loop does not block, so it is safe 2152 * to use TAILQ_FOREACH here. 2153 */ 2154 head = unp_heads[h]; 2155 TAILQ_FOREACH(unp, &head->list, unp_link) 2156 unp->unp_gcflags = 0; 2157 } 2158 2159 /* 2160 * Scan marking all reachable sockets with UNPGC_REF. Once a socket 2161 * is reachable all of the sockets it references are reachable. 2162 * Stop the scan once we do a complete loop without discovering 2163 * a new reachable socket. 2164 */ 2165 do { 2166 unp_unreachable = 0; 2167 unp_marked = 0; 2168 for (h = 0; unp_heads[h] != NULL; ++h) { 2169 head = unp_heads[h]; 2170 TAILQ_INSERT_HEAD(&head->list, unp_gc_marker, unp_link); 2171 while ((unp = TAILQ_NEXT(unp_gc_marker, unp_link)) 2172 != NULL) { 2173 TAILQ_REMOVE(&head->list, unp_gc_marker, 2174 unp_link); 2175 TAILQ_INSERT_AFTER(&head->list, unp, 2176 unp_gc_marker, unp_link); 2177 2178 if (unp->unp_flags & UNP_MARKER) 2179 continue; 2180 unp_gc_process(unp); 2181 } 2182 TAILQ_REMOVE(&head->list, unp_gc_marker, unp_link); 2183 } 2184 } while (unp_marked); 2185 2186 if (unp_unreachable == 0) 2187 goto done; 2188 2189 /* 2190 * We grab an extra reference to each of the file table entries 2191 * that are not otherwise accessible and then free the rights 2192 * that are stored in messages on them. 2193 * 2194 * The bug in the orginal code is a little tricky, so I'll describe 2195 * what's wrong with it here. 2196 * 2197 * It is incorrect to simply unp_discard each entry for f_msgcount 2198 * times -- consider the case of sockets A and B that contain 2199 * references to each other. On a last close of some other socket, 2200 * we trigger a gc since the number of outstanding rights (unp_rights) 2201 * is non-zero. If during the sweep phase the gc code unp_discards, 2202 * we end up doing a (full) fdrop on the descriptor. A fdrop on A 2203 * results in the following chain. Closef calls soo_close, which 2204 * calls soclose. Soclose calls first (through the switch 2205 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2206 * returns because the previous instance had set unp_gcing, and 2207 * we return all the way back to soclose, which marks the socket 2208 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 2209 * to free up the rights that are queued in messages on the socket A, 2210 * i.e., the reference on B. The sorflush calls via the dom_dispose 2211 * switch unp_dispose, which unp_scans with unp_discard. This second 2212 * instance of unp_discard just calls fdrop on B. 2213 * 2214 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2215 * which results in another fdrop on A. Unfortunately, A is already 2216 * being closed, and the descriptor has already been marked with 2217 * SS_NOFDREF, and soclose panics at this point. 2218 * 2219 * Here, we first take an extra reference to each inaccessible 2220 * descriptor. Then, we call sorflush ourself, since we know 2221 * it is a Unix domain socket anyhow. After we destroy all the 2222 * rights carried in messages, we do a last fdrop to get rid 2223 * of our extra reference. This is the last close, and the 2224 * unp_detach etc will shut down the socket. 2225 * 2226 * 91/09/19, bsy@cs.cmu.edu 2227 */ 2228 2229 filemax = unp_unreachable; 2230 if (filemax > UNP_GCFILE_MAX) 2231 filemax = UNP_GCFILE_MAX; 2232 unref = kmalloc(filemax * sizeof(struct file *), M_TEMP, M_WAITOK); 2233 2234 filetot = 0; 2235 do { 2236 int i; 2237 2238 /* 2239 * Iterate looking for sockets which have been specifically 2240 * marked as as unreachable and store them locally. 2241 */ 2242 fileidx = 0; 2243 for (h = 0; unp_heads[h] != NULL; ++h) { 2244 /* 2245 * NOTE: This loop does not block, so it is safe 2246 * to use TAILQ_FOREACH here. 2247 */ 2248 head = unp_heads[h]; 2249 TAILQ_FOREACH(unp, &head->list, unp_link) { 2250 struct file *fp; 2251 2252 if ((unp->unp_gcflags & UNPGC_DEAD) == 0) 2253 continue; 2254 unp->unp_gcflags &= ~UNPGC_DEAD; 2255 2256 fp = unp->unp_fp; 2257 if (unp->unp_msgcount == 0 || fp == NULL || 2258 fp->f_count != unp->unp_msgcount) 2259 continue; 2260 fhold(fp); 2261 2262 KASSERT(fileidx < filemax, 2263 ("invalid fileidx %d, filemax %d", 2264 fileidx, filemax)); 2265 unref[fileidx++] = fp; 2266 2267 KASSERT(filetot < unp_unreachable, 2268 ("invalid filetot %d and " 2269 "unp_unreachable %d", 2270 filetot, unp_unreachable)); 2271 ++filetot; 2272 2273 if (fileidx == filemax || 2274 filetot == unp_unreachable) 2275 goto dogc; 2276 } 2277 } 2278 dogc: 2279 /* 2280 * For each Unix domain socket on our hit list, do the 2281 * following two things. 2282 */ 2283 for (i = 0; i < fileidx; ++i) 2284 sorflush(unref[i]->f_data); 2285 for (i = 0; i < fileidx; ++i) 2286 fdrop(unref[i]); 2287 } while (fileidx == filemax && filetot < unp_unreachable); 2288 kfree(unref, M_TEMP); 2289 done: 2290 lwkt_reltoken(&unp_token); 2291 lwkt_reltoken(&unp_rights_token); 2292 } 2293 2294 #endif /* UNP_GC_ALLFILES */ 2295 2296 /* 2297 * Dispose of the fp's stored in a mbuf. 2298 * 2299 * The dds loop can cause additional fps to be entered onto the 2300 * list while it is running, flattening out the operation and avoiding 2301 * a deep kernel stack recursion. 2302 */ 2303 void 2304 unp_dispose(struct mbuf *m) 2305 { 2306 lwkt_gettoken(&unp_rights_token); 2307 if (m) 2308 unp_scan(m, unp_discard, NULL); 2309 lwkt_reltoken(&unp_rights_token); 2310 } 2311 2312 static int 2313 unp_listen(struct unpcb *unp, struct thread *td) 2314 { 2315 struct proc *p = td->td_proc; 2316 2317 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2318 UNP_ASSERT_TOKEN_HELD(unp); 2319 2320 KKASSERT(p); 2321 cru2x(p->p_ucred, &unp->unp_peercred); 2322 unp_setflags(unp, UNP_HAVEPCCACHED); 2323 return (0); 2324 } 2325 2326 static void 2327 unp_scan(struct mbuf *m0, void (*op)(struct file *, void *), void *data) 2328 { 2329 struct mbuf *m; 2330 struct file **rp; 2331 struct cmsghdr *cm; 2332 int i; 2333 int qfds; 2334 2335 while (m0) { 2336 for (m = m0; m; m = m->m_next) { 2337 if (m->m_type == MT_CONTROL && 2338 m->m_len >= sizeof(*cm)) { 2339 cm = mtod(m, struct cmsghdr *); 2340 if (cm->cmsg_level != SOL_SOCKET || 2341 cm->cmsg_type != SCM_RIGHTS) 2342 continue; 2343 qfds = (cm->cmsg_len - CMSG_LEN(0)) / 2344 sizeof(void *); 2345 rp = (struct file **)CMSG_DATA(cm); 2346 for (i = 0; i < qfds; i++) 2347 (*op)(*rp++, data); 2348 break; /* XXX, but saves time */ 2349 } 2350 } 2351 m0 = m0->m_nextpkt; 2352 } 2353 } 2354 2355 /* 2356 * Discard a fp previously held in a unix domain socket mbuf. To 2357 * avoid blowing out the kernel stack due to contrived chain-reactions 2358 * we may have to defer the operation to a dedicated taskqueue. 2359 * 2360 * Caller holds unp_rights_token. 2361 */ 2362 static void 2363 unp_discard(struct file *fp, void *data __unused) 2364 { 2365 unp_del_right(fp); 2366 if (unp_fp2unpcb(fp) != NULL) { 2367 struct unp_defdiscard *d; 2368 2369 /* 2370 * This fp is a Unix domain socket itself and fdrop() 2371 * it here directly may cause deep unp_discard() 2372 * recursion, so the fdrop() is defered to the 2373 * dedicated taskqueue. 2374 */ 2375 d = kmalloc(sizeof(*d), M_UNPCB, M_WAITOK); 2376 d->fp = fp; 2377 2378 spin_lock(&unp_defdiscard_spin); 2379 SLIST_INSERT_HEAD(&unp_defdiscard_head, d, next); 2380 spin_unlock(&unp_defdiscard_spin); 2381 2382 taskqueue_enqueue(unp_taskqueue, &unp_defdiscard_task); 2383 } else { 2384 /* This fp is not a Unix domain socket */ 2385 fdrop(fp); 2386 } 2387 } 2388 2389 /* 2390 * NOTE: 2391 * unp_token must be held before calling this function to avoid name 2392 * resolution and v_socket accessing races, especially racing against 2393 * the unp_detach(). 2394 * 2395 * NOTE: 2396 * For anyone caring about unconnected Unix domain socket sending 2397 * performance, other approach could be taken... 2398 */ 2399 static int 2400 unp_find_lockref(struct sockaddr *nam, struct thread *td, short type, 2401 struct unpcb **unp_ret) 2402 { 2403 struct proc *p = td->td_proc; 2404 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 2405 struct vnode *vp = NULL; 2406 struct socket *so; 2407 struct unpcb *unp; 2408 int error, len; 2409 struct nlookupdata nd; 2410 char buf[SOCK_MAXADDRLEN]; 2411 2412 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2413 2414 *unp_ret = NULL; 2415 2416 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 2417 if (len <= 0) { 2418 error = EINVAL; 2419 goto failed; 2420 } 2421 strncpy(buf, soun->sun_path, len); 2422 buf[len] = 0; 2423 2424 error = nlookup_init(&nd, buf, UIO_SYSSPACE, NLC_FOLLOW); 2425 if (error == 0) 2426 error = nlookup(&nd); 2427 if (error == 0) 2428 error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &vp); 2429 nlookup_done(&nd); 2430 if (error) { 2431 vp = NULL; 2432 goto failed; 2433 } 2434 2435 if (vp->v_type != VSOCK) { 2436 error = ENOTSOCK; 2437 goto failed; 2438 } 2439 error = VOP_EACCESS(vp, VWRITE, p->p_ucred); 2440 if (error) 2441 goto failed; 2442 so = vp->v_socket; 2443 if (so == NULL) { 2444 error = ECONNREFUSED; 2445 goto failed; 2446 } 2447 if (so->so_type != type) { 2448 error = EPROTOTYPE; 2449 goto failed; 2450 } 2451 2452 /* Lock this unp. */ 2453 unp = unp_getsocktoken(so); 2454 if (!UNP_ISATTACHED(unp)) { 2455 unp_reltoken(unp); 2456 error = ECONNREFUSED; 2457 goto failed; 2458 } 2459 /* And keep this unp referenced. */ 2460 unp_reference(unp); 2461 2462 /* Done! */ 2463 *unp_ret = unp; 2464 error = 0; 2465 failed: 2466 if (vp != NULL) 2467 vput(vp); 2468 return error; 2469 } 2470 2471 static int 2472 unp_connect_pair(struct unpcb *unp, struct unpcb *unp2) 2473 { 2474 struct socket *so = unp->unp_socket; 2475 struct socket *so2 = unp2->unp_socket; 2476 2477 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2478 UNP_ASSERT_TOKEN_HELD(unp); 2479 UNP_ASSERT_TOKEN_HELD(unp2); 2480 2481 KASSERT(so->so_type == so2->so_type, 2482 ("socket type mismatch, so %d, so2 %d", so->so_type, so2->so_type)); 2483 2484 if (!UNP_ISATTACHED(unp)) 2485 return EINVAL; 2486 if (!UNP_ISATTACHED(unp2)) 2487 return ECONNREFUSED; 2488 2489 KASSERT(unp->unp_conn == NULL, ("unp is already connected")); 2490 unp->unp_conn = unp2; 2491 2492 switch (so->so_type) { 2493 case SOCK_DGRAM: 2494 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 2495 soisconnected(so); 2496 break; 2497 2498 case SOCK_STREAM: 2499 case SOCK_SEQPACKET: 2500 KASSERT(unp2->unp_conn == NULL, ("unp2 is already connected")); 2501 unp2->unp_conn = unp; 2502 soisconnected(so); 2503 soisconnected(so2); 2504 break; 2505 2506 default: 2507 panic("unp_connect_pair: unknown socket type %d", so->so_type); 2508 } 2509 return 0; 2510 } 2511 2512 static void 2513 unp_drop(struct unpcb *unp, int error) 2514 { 2515 struct unp_global_head *head; 2516 struct unpcb *unp2; 2517 2518 ASSERT_LWKT_TOKEN_HELD(&unp_token); 2519 UNP_ASSERT_TOKEN_HELD(unp); 2520 2521 KASSERT((unp->unp_flags & (UNP_DETACHED | UNP_DROPPED)) == 0, 2522 ("unp is dropped")); 2523 2524 /* Mark this unp as detached. */ 2525 unp_setflags(unp, UNP_DETACHED); 2526 2527 /* Remove this unp from the global unp list. */ 2528 head = unp_globalhead(unp->unp_socket->so_type); 2529 KASSERT(head->count > 0, ("invalid unp count")); 2530 TAILQ_REMOVE(&head->list, unp, unp_link); 2531 head->count--; 2532 2533 /* Disconnect all. */ 2534 unp_disconnect(unp, error); 2535 while ((unp2 = LIST_FIRST(&unp->unp_refs)) != NULL) { 2536 lwkt_getpooltoken(unp2); 2537 unp_disconnect(unp2, ECONNRESET); 2538 lwkt_relpooltoken(unp2); 2539 } 2540 unp_setflags(unp, UNP_DROPPED); 2541 2542 /* Try freeing this unp. */ 2543 unp_free(unp); 2544 } 2545 2546 static void 2547 unp_defdiscard_taskfunc(void *arg __unused, int pending __unused) 2548 { 2549 struct unp_defdiscard *d; 2550 2551 spin_lock(&unp_defdiscard_spin); 2552 while ((d = SLIST_FIRST(&unp_defdiscard_head)) != NULL) { 2553 SLIST_REMOVE_HEAD(&unp_defdiscard_head, next); 2554 spin_unlock(&unp_defdiscard_spin); 2555 2556 fdrop(d->fp); 2557 kfree(d, M_UNPCB); 2558 2559 spin_lock(&unp_defdiscard_spin); 2560 } 2561 spin_unlock(&unp_defdiscard_spin); 2562 } 2563