1 /* $NetBSD: uipc_usrreq.c,v 1.112 2008/04/24 11:38:36 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000, 2004, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1989, 1991, 1993 42 * The Regents of the University of California. All rights reserved. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. Neither the name of the University nor the names of its contributors 53 * may be used to endorse or promote products derived from this software 54 * without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 58 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 59 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 60 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 61 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 62 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 64 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 66 * SUCH DAMAGE. 67 * 68 * @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95 69 */ 70 71 /* 72 * Copyright (c) 1997 Christopher G. Demetriou. All rights reserved. 73 * 74 * Redistribution and use in source and binary forms, with or without 75 * modification, are permitted provided that the following conditions 76 * are met: 77 * 1. Redistributions of source code must retain the above copyright 78 * notice, this list of conditions and the following disclaimer. 79 * 2. Redistributions in binary form must reproduce the above copyright 80 * notice, this list of conditions and the following disclaimer in the 81 * documentation and/or other materials provided with the distribution. 82 * 3. All advertising materials mentioning features or use of this software 83 * must display the following acknowledgement: 84 * This product includes software developed by the University of 85 * California, Berkeley and its contributors. 86 * 4. Neither the name of the University nor the names of its contributors 87 * may be used to endorse or promote products derived from this software 88 * without specific prior written permission. 89 * 90 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 91 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 92 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 93 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 94 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 95 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 96 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 97 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 98 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 99 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 100 * SUCH DAMAGE. 101 * 102 * @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95 103 */ 104 105 #include <sys/cdefs.h> 106 __KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.112 2008/04/24 11:38:36 ad Exp $"); 107 108 #include <sys/param.h> 109 #include <sys/systm.h> 110 #include <sys/proc.h> 111 #include <sys/filedesc.h> 112 #include <sys/domain.h> 113 #include <sys/protosw.h> 114 #include <sys/socket.h> 115 #include <sys/socketvar.h> 116 #include <sys/unpcb.h> 117 #include <sys/un.h> 118 #include <sys/namei.h> 119 #include <sys/vnode.h> 120 #include <sys/file.h> 121 #include <sys/stat.h> 122 #include <sys/mbuf.h> 123 #include <sys/kauth.h> 124 #include <sys/kmem.h> 125 #include <sys/atomic.h> 126 127 /* 128 * Unix communications domain. 129 * 130 * TODO: 131 * SEQPACKET, RDM 132 * rethink name space problems 133 * need a proper out-of-band 134 * 135 * Notes on locking: 136 * 137 * The generic rules noted in uipc_socket2.c apply. In addition: 138 * 139 * o We have a global lock, uipc_lock. 140 * 141 * o All datagram sockets are locked by uipc_lock. 142 * 143 * o For stream socketpairs, the two endpoints are created sharing the same 144 * independent lock. Sockets presented to PRU_CONNECT2 must already have 145 * matching locks. 146 * 147 * o Stream sockets created via socket() start life with their own 148 * independent lock. 149 * 150 * o Stream connections to a named endpoint are slightly more complicated. 151 * Sockets that have called listen() have their lock pointer mutated to 152 * the global uipc_lock. When establishing a connection, the connecting 153 * socket also has its lock mutated to uipc_lock, which matches the head 154 * (listening socket). We create a new socket for accept() to return, and 155 * that also shares the head's lock. Until the connection is completely 156 * done on both ends, all three sockets are locked by uipc_lock. Once the 157 * connection is complete, the association with the head's lock is broken. 158 * The connecting socket and the socket returned from accept() have their 159 * lock pointers mutated away from uipc_lock, and back to the connecting 160 * socket's original, independent lock. The head continues to be locked 161 * by uipc_lock. 162 * 163 * o If uipc_lock is determined to be a significant source of contention, 164 * it could easily be hashed out. It is difficult to simply make it an 165 * independent lock because of visibility / garbage collection issues: 166 * if a socket has been associated with a lock at any point, that lock 167 * must remain valid until the socket is no longer visible in the system. 168 * The lock must not be freed or otherwise destroyed until any sockets 169 * that had referenced it have also been destroyed. 170 */ 171 const struct sockaddr_un sun_noname = { 172 .sun_len = sizeof(sun_noname), 173 .sun_family = AF_LOCAL, 174 }; 175 ino_t unp_ino; /* prototype for fake inode numbers */ 176 177 struct mbuf *unp_addsockcred(struct lwp *, struct mbuf *); 178 static kmutex_t *uipc_lock; 179 180 /* 181 * Initialize Unix protocols. 182 */ 183 void 184 uipc_init(void) 185 { 186 187 uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 188 } 189 190 /* 191 * A connection succeeded: disassociate both endpoints from the head's 192 * lock, and make them share their own lock. There is a race here: for 193 * a very brief time one endpoint will be locked by a different lock 194 * than the other end. However, since the current thread holds the old 195 * lock (the listening socket's lock, the head) access can still only be 196 * made to one side of the connection. 197 */ 198 static void 199 unp_setpeerlocks(struct socket *so, struct socket *so2) 200 { 201 struct unpcb *unp; 202 kmutex_t *lock; 203 204 KASSERT(solocked2(so, so2)); 205 206 /* 207 * Bail out if either end of the socket is not yet fully 208 * connected or accepted. We only break the lock association 209 * with the head when the pair of sockets stand completely 210 * on their own. 211 */ 212 if (so->so_head != NULL || so2->so_head != NULL) 213 return; 214 215 /* 216 * Drop references to old lock. A third reference (from the 217 * queue head) must be held as we still hold its lock. Bonus: 218 * we don't need to worry about garbage collecting the lock. 219 */ 220 lock = so->so_lock; 221 KASSERT(lock == uipc_lock); 222 mutex_obj_free(lock); 223 mutex_obj_free(lock); 224 225 /* 226 * Grab stream lock from the initiator and share between the two 227 * endpoints. Issue memory barrier to ensure all modifications 228 * become globally visible before the lock change. so2 is 229 * assumed not to have a stream lock, because it was created 230 * purely for the server side to accept this connection and 231 * started out life using the domain-wide lock. 232 */ 233 unp = sotounpcb(so); 234 KASSERT(unp->unp_streamlock != NULL); 235 KASSERT(sotounpcb(so2)->unp_streamlock == NULL); 236 lock = unp->unp_streamlock; 237 unp->unp_streamlock = NULL; 238 mutex_obj_hold(lock); 239 membar_exit(); 240 so->so_lock = lock; 241 so2->so_lock = lock; 242 } 243 244 /* 245 * Reset a socket's lock back to the domain-wide lock. 246 */ 247 static void 248 unp_resetlock(struct socket *so) 249 { 250 kmutex_t *olock, *nlock; 251 struct unpcb *unp; 252 253 KASSERT(solocked(so)); 254 255 olock = so->so_lock; 256 nlock = uipc_lock; 257 if (olock == nlock) 258 return; 259 unp = sotounpcb(so); 260 KASSERT(unp->unp_streamlock == NULL); 261 unp->unp_streamlock = olock; 262 mutex_obj_hold(nlock); 263 mutex_enter(nlock); 264 so->so_lock = nlock; 265 mutex_exit(olock); 266 } 267 268 static void 269 unp_free(struct unpcb *unp) 270 { 271 272 if (unp->unp_addr) 273 free(unp->unp_addr, M_SONAME); 274 if (unp->unp_streamlock != NULL) 275 mutex_obj_free(unp->unp_streamlock); 276 free(unp, M_PCB); 277 } 278 279 int 280 unp_output(struct mbuf *m, struct mbuf *control, struct unpcb *unp, 281 struct lwp *l) 282 { 283 struct socket *so2; 284 const struct sockaddr_un *sun; 285 286 so2 = unp->unp_conn->unp_socket; 287 288 KASSERT(solocked(so2)); 289 290 if (unp->unp_addr) 291 sun = unp->unp_addr; 292 else 293 sun = &sun_noname; 294 if (unp->unp_conn->unp_flags & UNP_WANTCRED) 295 control = unp_addsockcred(l, control); 296 if (sbappendaddr(&so2->so_rcv, (const struct sockaddr *)sun, m, 297 control) == 0) { 298 so2->so_rcv.sb_overflowed++; 299 sounlock(so2); 300 unp_dispose(control); 301 m_freem(control); 302 m_freem(m); 303 solock(so2); 304 return (ENOBUFS); 305 } else { 306 sorwakeup(so2); 307 return (0); 308 } 309 } 310 311 void 312 unp_setaddr(struct socket *so, struct mbuf *nam, bool peeraddr) 313 { 314 const struct sockaddr_un *sun; 315 struct unpcb *unp; 316 bool ext; 317 318 unp = sotounpcb(so); 319 ext = false; 320 321 for (;;) { 322 sun = NULL; 323 if (peeraddr) { 324 if (unp->unp_conn && unp->unp_conn->unp_addr) 325 sun = unp->unp_conn->unp_addr; 326 } else { 327 if (unp->unp_addr) 328 sun = unp->unp_addr; 329 } 330 if (sun == NULL) 331 sun = &sun_noname; 332 nam->m_len = sun->sun_len; 333 if (nam->m_len > MLEN && !ext) { 334 sounlock(so); 335 MEXTMALLOC(nam, MAXPATHLEN * 2, M_WAITOK); 336 solock(so); 337 ext = true; 338 } else { 339 KASSERT(nam->m_len <= MAXPATHLEN * 2); 340 memcpy(mtod(nam, void *), sun, (size_t)nam->m_len); 341 break; 342 } 343 } 344 } 345 346 /*ARGSUSED*/ 347 int 348 uipc_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam, 349 struct mbuf *control, struct lwp *l) 350 { 351 struct unpcb *unp = sotounpcb(so); 352 struct socket *so2; 353 struct proc *p; 354 u_int newhiwat; 355 int error = 0; 356 357 if (req == PRU_CONTROL) 358 return (EOPNOTSUPP); 359 360 #ifdef DIAGNOSTIC 361 if (req != PRU_SEND && req != PRU_SENDOOB && control) 362 panic("uipc_usrreq: unexpected control mbuf"); 363 #endif 364 p = l ? l->l_proc : NULL; 365 if (req != PRU_ATTACH) { 366 if (unp == 0) { 367 error = EINVAL; 368 goto release; 369 } 370 KASSERT(solocked(so)); 371 } 372 373 switch (req) { 374 375 case PRU_ATTACH: 376 if (unp != 0) { 377 error = EISCONN; 378 break; 379 } 380 error = unp_attach(so); 381 break; 382 383 case PRU_DETACH: 384 unp_detach(unp); 385 break; 386 387 case PRU_BIND: 388 KASSERT(l != NULL); 389 error = unp_bind(so, nam, l); 390 break; 391 392 case PRU_LISTEN: 393 /* 394 * If the socket can accept a connection, it must be 395 * locked by uipc_lock. 396 */ 397 unp_resetlock(so); 398 if (unp->unp_vnode == 0) 399 error = EINVAL; 400 break; 401 402 case PRU_CONNECT: 403 KASSERT(l != NULL); 404 error = unp_connect(so, nam, l); 405 break; 406 407 case PRU_CONNECT2: 408 error = unp_connect2(so, (struct socket *)nam, PRU_CONNECT2); 409 break; 410 411 case PRU_DISCONNECT: 412 unp_disconnect(unp); 413 break; 414 415 case PRU_ACCEPT: 416 KASSERT(so->so_lock == uipc_lock); 417 /* 418 * Mark the initiating STREAM socket as connected *ONLY* 419 * after it's been accepted. This prevents a client from 420 * overrunning a server and receiving ECONNREFUSED. 421 */ 422 if (unp->unp_conn == NULL) 423 break; 424 so2 = unp->unp_conn->unp_socket; 425 if (so2->so_state & SS_ISCONNECTING) { 426 KASSERT(solocked2(so, so->so_head)); 427 KASSERT(solocked2(so2, so->so_head)); 428 soisconnected(so2); 429 } 430 /* 431 * If the connection is fully established, break the 432 * association with uipc_lock and give the connected 433 * pair a seperate lock to share. 434 */ 435 unp_setpeerlocks(so2, so); 436 /* 437 * Only now return peer's address, as we may need to 438 * block in order to allocate memory. 439 * 440 * XXX Minor race: connection can be broken while 441 * lock is dropped in unp_setaddr(). We will return 442 * error == 0 and sun_noname as the peer address. 443 */ 444 unp_setaddr(so, nam, true); 445 break; 446 447 case PRU_SHUTDOWN: 448 socantsendmore(so); 449 unp_shutdown(unp); 450 break; 451 452 case PRU_RCVD: 453 switch (so->so_type) { 454 455 case SOCK_DGRAM: 456 panic("uipc 1"); 457 /*NOTREACHED*/ 458 459 case SOCK_STREAM: 460 #define rcv (&so->so_rcv) 461 #define snd (&so2->so_snd) 462 if (unp->unp_conn == 0) 463 break; 464 so2 = unp->unp_conn->unp_socket; 465 KASSERT(solocked2(so, so2)); 466 /* 467 * Adjust backpressure on sender 468 * and wakeup any waiting to write. 469 */ 470 snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt; 471 unp->unp_mbcnt = rcv->sb_mbcnt; 472 newhiwat = snd->sb_hiwat + unp->unp_cc - rcv->sb_cc; 473 (void)chgsbsize(so2->so_uidinfo, 474 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 475 unp->unp_cc = rcv->sb_cc; 476 sowwakeup(so2); 477 #undef snd 478 #undef rcv 479 break; 480 481 default: 482 panic("uipc 2"); 483 } 484 break; 485 486 case PRU_SEND: 487 /* 488 * Note: unp_internalize() rejects any control message 489 * other than SCM_RIGHTS, and only allows one. This 490 * has the side-effect of preventing a caller from 491 * forging SCM_CREDS. 492 */ 493 if (control) { 494 sounlock(so); 495 error = unp_internalize(&control); 496 solock(so); 497 if (error != 0) { 498 m_freem(control); 499 m_freem(m); 500 break; 501 } 502 } 503 switch (so->so_type) { 504 505 case SOCK_DGRAM: { 506 KASSERT(so->so_lock == uipc_lock); 507 if (nam) { 508 if ((so->so_state & SS_ISCONNECTED) != 0) 509 error = EISCONN; 510 else { 511 /* 512 * Note: once connected, the 513 * socket's lock must not be 514 * dropped until we have sent 515 * the message and disconnected. 516 * This is necessary to prevent 517 * intervening control ops, like 518 * another connection. 519 */ 520 error = unp_connect(so, nam, l); 521 } 522 } else { 523 if ((so->so_state & SS_ISCONNECTED) == 0) 524 error = ENOTCONN; 525 } 526 if (error) { 527 sounlock(so); 528 unp_dispose(control); 529 m_freem(control); 530 m_freem(m); 531 solock(so); 532 break; 533 } 534 KASSERT(p != NULL); 535 error = unp_output(m, control, unp, l); 536 if (nam) 537 unp_disconnect(unp); 538 break; 539 } 540 541 case SOCK_STREAM: 542 #define rcv (&so2->so_rcv) 543 #define snd (&so->so_snd) 544 if (unp->unp_conn == NULL) { 545 error = ENOTCONN; 546 break; 547 } 548 so2 = unp->unp_conn->unp_socket; 549 KASSERT(solocked2(so, so2)); 550 if (unp->unp_conn->unp_flags & UNP_WANTCRED) { 551 /* 552 * Credentials are passed only once on 553 * SOCK_STREAM. 554 */ 555 unp->unp_conn->unp_flags &= ~UNP_WANTCRED; 556 control = unp_addsockcred(l, control); 557 } 558 /* 559 * Send to paired receive port, and then reduce 560 * send buffer hiwater marks to maintain backpressure. 561 * Wake up readers. 562 */ 563 if (control) { 564 if (sbappendcontrol(rcv, m, control) != 0) 565 control = NULL; 566 } else 567 sbappend(rcv, m); 568 snd->sb_mbmax -= 569 rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt; 570 unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt; 571 newhiwat = snd->sb_hiwat - 572 (rcv->sb_cc - unp->unp_conn->unp_cc); 573 (void)chgsbsize(so->so_uidinfo, 574 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 575 unp->unp_conn->unp_cc = rcv->sb_cc; 576 sorwakeup(so2); 577 #undef snd 578 #undef rcv 579 if (control != NULL) { 580 sounlock(so); 581 unp_dispose(control); 582 m_freem(control); 583 solock(so); 584 } 585 break; 586 587 default: 588 panic("uipc 4"); 589 } 590 break; 591 592 case PRU_ABORT: 593 (void)unp_drop(unp, ECONNABORTED); 594 595 KASSERT(so->so_head == NULL); 596 #ifdef DIAGNOSTIC 597 if (so->so_pcb == 0) 598 panic("uipc 5: drop killed pcb"); 599 #endif 600 unp_detach(unp); 601 break; 602 603 case PRU_SENSE: 604 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 605 if (so->so_type == SOCK_STREAM && unp->unp_conn != 0) { 606 so2 = unp->unp_conn->unp_socket; 607 KASSERT(solocked2(so, so2)); 608 ((struct stat *) m)->st_blksize += so2->so_rcv.sb_cc; 609 } 610 ((struct stat *) m)->st_dev = NODEV; 611 if (unp->unp_ino == 0) 612 unp->unp_ino = unp_ino++; 613 ((struct stat *) m)->st_atimespec = 614 ((struct stat *) m)->st_mtimespec = 615 ((struct stat *) m)->st_ctimespec = unp->unp_ctime; 616 ((struct stat *) m)->st_ino = unp->unp_ino; 617 return (0); 618 619 case PRU_RCVOOB: 620 error = EOPNOTSUPP; 621 break; 622 623 case PRU_SENDOOB: 624 m_freem(control); 625 m_freem(m); 626 error = EOPNOTSUPP; 627 break; 628 629 case PRU_SOCKADDR: 630 unp_setaddr(so, nam, false); 631 break; 632 633 case PRU_PEERADDR: 634 unp_setaddr(so, nam, true); 635 break; 636 637 default: 638 panic("piusrreq"); 639 } 640 641 release: 642 return (error); 643 } 644 645 /* 646 * Unix domain socket option processing. 647 */ 648 int 649 uipc_ctloutput(int op, struct socket *so, int level, int optname, 650 struct mbuf **mp) 651 { 652 struct unpcb *unp = sotounpcb(so); 653 struct mbuf *m = *mp; 654 int optval = 0, error = 0; 655 656 KASSERT(solocked(so)); 657 658 if (level != 0) { 659 error = ENOPROTOOPT; 660 if (op == PRCO_SETOPT && m) 661 (void) m_free(m); 662 } else switch (op) { 663 664 case PRCO_SETOPT: 665 switch (optname) { 666 case LOCAL_CREDS: 667 case LOCAL_CONNWAIT: 668 if (m == NULL || m->m_len != sizeof(int)) 669 error = EINVAL; 670 else { 671 optval = *mtod(m, int *); 672 switch (optname) { 673 #define OPTSET(bit) \ 674 if (optval) \ 675 unp->unp_flags |= (bit); \ 676 else \ 677 unp->unp_flags &= ~(bit); 678 679 case LOCAL_CREDS: 680 OPTSET(UNP_WANTCRED); 681 break; 682 case LOCAL_CONNWAIT: 683 OPTSET(UNP_CONNWAIT); 684 break; 685 } 686 } 687 break; 688 #undef OPTSET 689 690 default: 691 error = ENOPROTOOPT; 692 break; 693 } 694 if (m) 695 (void) m_free(m); 696 break; 697 698 case PRCO_GETOPT: 699 sounlock(so); 700 switch (optname) { 701 case LOCAL_PEEREID: 702 if (unp->unp_flags & UNP_EIDSVALID) { 703 *mp = m = m_get(M_WAIT, MT_SOOPTS); 704 m->m_len = sizeof(struct unpcbid); 705 *mtod(m, struct unpcbid *) = unp->unp_connid; 706 } else { 707 error = EINVAL; 708 } 709 break; 710 case LOCAL_CREDS: 711 *mp = m = m_get(M_WAIT, MT_SOOPTS); 712 m->m_len = sizeof(int); 713 714 #define OPTBIT(bit) (unp->unp_flags & (bit) ? 1 : 0) 715 716 optval = OPTBIT(UNP_WANTCRED); 717 *mtod(m, int *) = optval; 718 break; 719 #undef OPTBIT 720 721 default: 722 error = ENOPROTOOPT; 723 break; 724 } 725 solock(so); 726 break; 727 } 728 return (error); 729 } 730 731 /* 732 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 733 * for stream sockets, although the total for sender and receiver is 734 * actually only PIPSIZ. 735 * Datagram sockets really use the sendspace as the maximum datagram size, 736 * and don't really want to reserve the sendspace. Their recvspace should 737 * be large enough for at least one max-size datagram plus address. 738 */ 739 #define PIPSIZ 4096 740 u_long unpst_sendspace = PIPSIZ; 741 u_long unpst_recvspace = PIPSIZ; 742 u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 743 u_long unpdg_recvspace = 4*1024; 744 745 u_int unp_rights; /* file descriptors in flight */ 746 747 int 748 unp_attach(struct socket *so) 749 { 750 struct unpcb *unp; 751 int error; 752 753 switch (so->so_type) { 754 case SOCK_STREAM: 755 if (so->so_lock == NULL) { 756 /* 757 * XXX Assuming that no socket locks are held, 758 * as this call may sleep. 759 */ 760 so->so_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 761 solock(so); 762 } 763 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 764 error = soreserve(so, unpst_sendspace, unpst_recvspace); 765 if (error != 0) 766 return (error); 767 } 768 break; 769 770 case SOCK_DGRAM: 771 if (so->so_lock == NULL) { 772 mutex_obj_hold(uipc_lock); 773 so->so_lock = uipc_lock; 774 solock(so); 775 } 776 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 777 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 778 if (error != 0) 779 return (error); 780 } 781 break; 782 783 default: 784 panic("unp_attach"); 785 } 786 KASSERT(solocked(so)); 787 unp = malloc(sizeof(*unp), M_PCB, M_NOWAIT); 788 if (unp == NULL) 789 return (ENOBUFS); 790 memset((void *)unp, 0, sizeof(*unp)); 791 unp->unp_socket = so; 792 so->so_pcb = unp; 793 nanotime(&unp->unp_ctime); 794 return (0); 795 } 796 797 void 798 unp_detach(struct unpcb *unp) 799 { 800 struct socket *so; 801 vnode_t *vp; 802 803 so = unp->unp_socket; 804 805 retry: 806 if ((vp = unp->unp_vnode) != NULL) { 807 sounlock(so); 808 /* Acquire v_interlock to protect against unp_connect(). */ 809 mutex_enter(&vp->v_interlock); 810 vp->v_socket = NULL; 811 vrelel(vp, 0); 812 solock(so); 813 unp->unp_vnode = NULL; 814 } 815 if (unp->unp_conn) 816 unp_disconnect(unp); 817 while (unp->unp_refs) { 818 KASSERT(solocked2(so, unp->unp_refs->unp_socket)); 819 if (unp_drop(unp->unp_refs, ECONNRESET)) { 820 solock(so); 821 goto retry; 822 } 823 } 824 soisdisconnected(so); 825 so->so_pcb = NULL; 826 if (unp_rights) { 827 /* 828 * Normally the receive buffer is flushed later, 829 * in sofree, but if our receive buffer holds references 830 * to descriptors that are now garbage, we will dispose 831 * of those descriptor references after the garbage collector 832 * gets them (resulting in a "panic: closef: count < 0"). 833 */ 834 sorflush(so); 835 unp_free(unp); 836 sounlock(so); 837 unp_gc(); 838 solock(so); 839 } else 840 unp_free(unp); 841 } 842 843 int 844 unp_bind(struct socket *so, struct mbuf *nam, struct lwp *l) 845 { 846 struct sockaddr_un *sun; 847 struct unpcb *unp; 848 vnode_t *vp; 849 struct vattr vattr; 850 size_t addrlen; 851 int error; 852 struct nameidata nd; 853 proc_t *p; 854 855 unp = sotounpcb(so); 856 if (unp->unp_vnode != NULL) 857 return (EINVAL); 858 if ((unp->unp_flags & UNP_BUSY) != 0) { 859 /* 860 * EALREADY may not be strictly accurate, but since this 861 * is a major application error it's hardly a big deal. 862 */ 863 return (EALREADY); 864 } 865 unp->unp_flags |= UNP_BUSY; 866 sounlock(so); 867 868 /* 869 * Allocate the new sockaddr. We have to allocate one 870 * extra byte so that we can ensure that the pathname 871 * is nul-terminated. 872 */ 873 p = l->l_proc; 874 addrlen = nam->m_len + 1; 875 sun = malloc(addrlen, M_SONAME, M_WAITOK); 876 m_copydata(nam, 0, nam->m_len, (void *)sun); 877 *(((char *)sun) + nam->m_len) = '\0'; 878 879 NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, UIO_SYSSPACE, 880 sun->sun_path); 881 882 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 883 if ((error = namei(&nd)) != 0) 884 goto bad; 885 vp = nd.ni_vp; 886 if (vp != NULL) { 887 VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd); 888 if (nd.ni_dvp == vp) 889 vrele(nd.ni_dvp); 890 else 891 vput(nd.ni_dvp); 892 vrele(vp); 893 error = EADDRINUSE; 894 goto bad; 895 } 896 VATTR_NULL(&vattr); 897 vattr.va_type = VSOCK; 898 vattr.va_mode = ACCESSPERMS & ~(p->p_cwdi->cwdi_cmask); 899 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 900 if (error) 901 goto bad; 902 vp = nd.ni_vp; 903 solock(so); 904 vp->v_socket = unp->unp_socket; 905 unp->unp_vnode = vp; 906 unp->unp_addrlen = addrlen; 907 unp->unp_addr = sun; 908 unp->unp_connid.unp_pid = p->p_pid; 909 unp->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 910 unp->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 911 unp->unp_flags |= UNP_EIDSBIND; 912 VOP_UNLOCK(vp, 0); 913 unp->unp_flags &= ~UNP_BUSY; 914 return (0); 915 916 bad: 917 free(sun, M_SONAME); 918 solock(so); 919 unp->unp_flags &= ~UNP_BUSY; 920 return (error); 921 } 922 923 int 924 unp_connect(struct socket *so, struct mbuf *nam, struct lwp *l) 925 { 926 struct sockaddr_un *sun; 927 vnode_t *vp; 928 struct socket *so2, *so3; 929 struct unpcb *unp, *unp2, *unp3; 930 size_t addrlen; 931 int error; 932 struct nameidata nd; 933 934 unp = sotounpcb(so); 935 if ((unp->unp_flags & UNP_BUSY) != 0) { 936 /* 937 * EALREADY may not be strictly accurate, but since this 938 * is a major application error it's hardly a big deal. 939 */ 940 return (EALREADY); 941 } 942 unp->unp_flags |= UNP_BUSY; 943 sounlock(so); 944 945 /* 946 * Allocate a temporary sockaddr. We have to allocate one extra 947 * byte so that we can ensure that the pathname is nul-terminated. 948 * When we establish the connection, we copy the other PCB's 949 * sockaddr to our own. 950 */ 951 addrlen = nam->m_len + 1; 952 sun = malloc(addrlen, M_SONAME, M_WAITOK); 953 m_copydata(nam, 0, nam->m_len, (void *)sun); 954 *(((char *)sun) + nam->m_len) = '\0'; 955 956 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, UIO_SYSSPACE, 957 sun->sun_path); 958 959 if ((error = namei(&nd)) != 0) 960 goto bad2; 961 vp = nd.ni_vp; 962 if (vp->v_type != VSOCK) { 963 error = ENOTSOCK; 964 goto bad; 965 } 966 if ((error = VOP_ACCESS(vp, VWRITE, l->l_cred)) != 0) 967 goto bad; 968 /* Acquire v_interlock to protect against unp_detach(). */ 969 mutex_enter(&vp->v_interlock); 970 so2 = vp->v_socket; 971 if (so2 == NULL) { 972 mutex_exit(&vp->v_interlock); 973 error = ECONNREFUSED; 974 goto bad; 975 } 976 if (so->so_type != so2->so_type) { 977 mutex_exit(&vp->v_interlock); 978 error = EPROTOTYPE; 979 goto bad; 980 } 981 solock(so); 982 unp_resetlock(so); 983 mutex_exit(&vp->v_interlock); 984 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { 985 /* 986 * This may seem somewhat fragile but is OK: if we can 987 * see SO_ACCEPTCONN set on the endpoint, then it must 988 * be locked by the domain-wide uipc_lock. 989 */ 990 KASSERT((so->so_options & SO_ACCEPTCONN) == 0 || 991 so2->so_lock == uipc_lock); 992 if ((so2->so_options & SO_ACCEPTCONN) == 0 || 993 (so3 = sonewconn(so2, 0)) == 0) { 994 error = ECONNREFUSED; 995 sounlock(so); 996 goto bad; 997 } 998 unp2 = sotounpcb(so2); 999 unp3 = sotounpcb(so3); 1000 if (unp2->unp_addr) { 1001 unp3->unp_addr = malloc(unp2->unp_addrlen, 1002 M_SONAME, M_WAITOK); 1003 memcpy(unp3->unp_addr, unp2->unp_addr, 1004 unp2->unp_addrlen); 1005 unp3->unp_addrlen = unp2->unp_addrlen; 1006 } 1007 unp3->unp_flags = unp2->unp_flags; 1008 unp3->unp_connid.unp_pid = l->l_proc->p_pid; 1009 unp3->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 1010 unp3->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 1011 unp3->unp_flags |= UNP_EIDSVALID; 1012 if (unp2->unp_flags & UNP_EIDSBIND) { 1013 unp->unp_connid = unp2->unp_connid; 1014 unp->unp_flags |= UNP_EIDSVALID; 1015 } 1016 so2 = so3; 1017 } 1018 error = unp_connect2(so, so2, PRU_CONNECT); 1019 sounlock(so); 1020 bad: 1021 vput(vp); 1022 bad2: 1023 free(sun, M_SONAME); 1024 solock(so); 1025 unp->unp_flags &= ~UNP_BUSY; 1026 return (error); 1027 } 1028 1029 int 1030 unp_connect2(struct socket *so, struct socket *so2, int req) 1031 { 1032 struct unpcb *unp = sotounpcb(so); 1033 struct unpcb *unp2; 1034 1035 if (so2->so_type != so->so_type) 1036 return (EPROTOTYPE); 1037 1038 /* 1039 * All three sockets involved must be locked by same lock: 1040 * 1041 * local endpoint (so) 1042 * remote endpoint (so2) 1043 * queue head (so->so_head, only if PR_CONNREQUIRED) 1044 */ 1045 KASSERT(solocked2(so, so2)); 1046 if (so->so_head != NULL) { 1047 KASSERT(so->so_lock == uipc_lock); 1048 KASSERT(solocked2(so, so->so_head)); 1049 } 1050 1051 unp2 = sotounpcb(so2); 1052 unp->unp_conn = unp2; 1053 switch (so->so_type) { 1054 1055 case SOCK_DGRAM: 1056 unp->unp_nextref = unp2->unp_refs; 1057 unp2->unp_refs = unp; 1058 soisconnected(so); 1059 break; 1060 1061 case SOCK_STREAM: 1062 unp2->unp_conn = unp; 1063 if (req == PRU_CONNECT && 1064 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1065 soisconnecting(so); 1066 else 1067 soisconnected(so); 1068 soisconnected(so2); 1069 /* 1070 * If the connection is fully established, break the 1071 * association with uipc_lock and give the connected 1072 * pair a seperate lock to share. For CONNECT2, we 1073 * require that the locks already match (the sockets 1074 * are created that way). 1075 */ 1076 if (req == PRU_CONNECT) 1077 unp_setpeerlocks(so, so2); 1078 break; 1079 1080 default: 1081 panic("unp_connect2"); 1082 } 1083 return (0); 1084 } 1085 1086 void 1087 unp_disconnect(struct unpcb *unp) 1088 { 1089 struct unpcb *unp2 = unp->unp_conn; 1090 struct socket *so; 1091 1092 if (unp2 == 0) 1093 return; 1094 unp->unp_conn = 0; 1095 so = unp->unp_socket; 1096 switch (so->so_type) { 1097 case SOCK_DGRAM: 1098 if (unp2->unp_refs == unp) 1099 unp2->unp_refs = unp->unp_nextref; 1100 else { 1101 unp2 = unp2->unp_refs; 1102 for (;;) { 1103 KASSERT(solocked2(so, unp2->unp_socket)); 1104 if (unp2 == 0) 1105 panic("unp_disconnect"); 1106 if (unp2->unp_nextref == unp) 1107 break; 1108 unp2 = unp2->unp_nextref; 1109 } 1110 unp2->unp_nextref = unp->unp_nextref; 1111 } 1112 unp->unp_nextref = 0; 1113 so->so_state &= ~SS_ISCONNECTED; 1114 break; 1115 1116 case SOCK_STREAM: 1117 KASSERT(solocked2(so, unp2->unp_socket)); 1118 soisdisconnected(so); 1119 unp2->unp_conn = 0; 1120 soisdisconnected(unp2->unp_socket); 1121 break; 1122 } 1123 } 1124 1125 #ifdef notdef 1126 unp_abort(struct unpcb *unp) 1127 { 1128 unp_detach(unp); 1129 } 1130 #endif 1131 1132 void 1133 unp_shutdown(struct unpcb *unp) 1134 { 1135 struct socket *so; 1136 1137 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1138 (so = unp->unp_conn->unp_socket)) 1139 socantrcvmore(so); 1140 } 1141 1142 bool 1143 unp_drop(struct unpcb *unp, int errno) 1144 { 1145 struct socket *so = unp->unp_socket; 1146 1147 KASSERT(solocked(so)); 1148 1149 so->so_error = errno; 1150 unp_disconnect(unp); 1151 if (so->so_head) { 1152 so->so_pcb = NULL; 1153 /* sofree() drops the socket lock */ 1154 sofree(so); 1155 unp_free(unp); 1156 return true; 1157 } 1158 return false; 1159 } 1160 1161 #ifdef notdef 1162 unp_drain(void) 1163 { 1164 1165 } 1166 #endif 1167 1168 int 1169 unp_externalize(struct mbuf *rights, struct lwp *l) 1170 { 1171 struct cmsghdr *cm = mtod(rights, struct cmsghdr *); 1172 struct proc *p = l->l_proc; 1173 int i, *fdp; 1174 file_t **rp; 1175 file_t *fp; 1176 int nfds, error = 0; 1177 1178 nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / 1179 sizeof(file_t *); 1180 rp = (file_t **)CMSG_DATA(cm); 1181 1182 fdp = malloc(nfds * sizeof(int), M_TEMP, M_WAITOK); 1183 rw_enter(&p->p_cwdi->cwdi_lock, RW_READER); 1184 1185 /* Make sure the recipient should be able to see the descriptors.. */ 1186 if (p->p_cwdi->cwdi_rdir != NULL) { 1187 rp = (file_t **)CMSG_DATA(cm); 1188 for (i = 0; i < nfds; i++) { 1189 fp = *rp++; 1190 /* 1191 * If we are in a chroot'ed directory, and 1192 * someone wants to pass us a directory, make 1193 * sure it's inside the subtree we're allowed 1194 * to access. 1195 */ 1196 if (fp->f_type == DTYPE_VNODE) { 1197 vnode_t *vp = (vnode_t *)fp->f_data; 1198 if ((vp->v_type == VDIR) && 1199 !vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) { 1200 error = EPERM; 1201 break; 1202 } 1203 } 1204 } 1205 } 1206 1207 restart: 1208 rp = (file_t **)CMSG_DATA(cm); 1209 if (error != 0) { 1210 for (i = 0; i < nfds; i++) { 1211 fp = *rp; 1212 /* 1213 * zero the pointer before calling unp_discard, 1214 * since it may end up in unp_gc().. 1215 */ 1216 *rp++ = 0; 1217 unp_discard(fp); 1218 } 1219 goto out; 1220 } 1221 1222 /* 1223 * First loop -- allocate file descriptor table slots for the 1224 * new descriptors. 1225 */ 1226 for (i = 0; i < nfds; i++) { 1227 fp = *rp++; 1228 if ((error = fd_alloc(p, 0, &fdp[i])) != 0) { 1229 /* 1230 * Back out what we've done so far. 1231 */ 1232 for (--i; i >= 0; i--) { 1233 fd_abort(p, NULL, fdp[i]); 1234 } 1235 if (error == ENOSPC) { 1236 fd_tryexpand(p); 1237 error = 0; 1238 } else { 1239 /* 1240 * This is the error that has historically 1241 * been returned, and some callers may 1242 * expect it. 1243 */ 1244 error = EMSGSIZE; 1245 } 1246 goto restart; 1247 } 1248 } 1249 1250 /* 1251 * Now that adding them has succeeded, update all of the 1252 * descriptor passing state. 1253 */ 1254 rp = (file_t **)CMSG_DATA(cm); 1255 for (i = 0; i < nfds; i++) { 1256 fp = *rp++; 1257 atomic_dec_uint(&unp_rights); 1258 fd_affix(p, fp, fdp[i]); 1259 mutex_enter(&fp->f_lock); 1260 fp->f_msgcount--; 1261 mutex_exit(&fp->f_lock); 1262 /* 1263 * Note that fd_affix() adds a reference to the file. 1264 * The file may already have been closed by another 1265 * LWP in the process, so we must drop the reference 1266 * added by unp_internalize() with closef(). 1267 */ 1268 closef(fp); 1269 } 1270 1271 /* 1272 * Copy temporary array to message and adjust length, in case of 1273 * transition from large file_t pointers to ints. 1274 */ 1275 memcpy(CMSG_DATA(cm), fdp, nfds * sizeof(int)); 1276 cm->cmsg_len = CMSG_LEN(nfds * sizeof(int)); 1277 rights->m_len = CMSG_SPACE(nfds * sizeof(int)); 1278 out: 1279 rw_exit(&p->p_cwdi->cwdi_lock); 1280 free(fdp, M_TEMP); 1281 return (error); 1282 } 1283 1284 int 1285 unp_internalize(struct mbuf **controlp) 1286 { 1287 struct filedesc *fdescp = curlwp->l_fd; 1288 struct mbuf *control = *controlp; 1289 struct cmsghdr *newcm, *cm = mtod(control, struct cmsghdr *); 1290 file_t **rp, **files; 1291 file_t *fp; 1292 int i, fd, *fdp; 1293 int nfds, error; 1294 1295 error = 0; 1296 newcm = NULL; 1297 1298 /* Sanity check the control message header. */ 1299 if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET || 1300 cm->cmsg_len != control->m_len) 1301 return (EINVAL); 1302 1303 /* 1304 * Verify that the file descriptors are valid, and acquire 1305 * a reference to each. 1306 */ 1307 nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / sizeof(int); 1308 fdp = (int *)CMSG_DATA(cm); 1309 for (i = 0; i < nfds; i++) { 1310 fd = *fdp++; 1311 if ((fp = fd_getfile(fd)) == NULL) { 1312 nfds = i + 1; 1313 error = EBADF; 1314 goto out; 1315 } 1316 } 1317 1318 /* Allocate new space and copy header into it. */ 1319 newcm = malloc(CMSG_SPACE(nfds * sizeof(file_t *)), M_MBUF, M_WAITOK); 1320 if (newcm == NULL) { 1321 error = E2BIG; 1322 goto out; 1323 } 1324 memcpy(newcm, cm, sizeof(struct cmsghdr)); 1325 files = (file_t **)CMSG_DATA(newcm); 1326 1327 /* 1328 * Transform the file descriptors into file_t pointers, in 1329 * reverse order so that if pointers are bigger than ints, the 1330 * int won't get until we're done. No need to lock, as we have 1331 * already validated the descriptors with fd_getfile(). 1332 */ 1333 fdp = (int *)CMSG_DATA(cm) + nfds; 1334 rp = files + nfds; 1335 for (i = 0; i < nfds; i++) { 1336 fp = fdescp->fd_ofiles[*--fdp]->ff_file; 1337 KASSERT(fp != NULL); 1338 mutex_enter(&fp->f_lock); 1339 *--rp = fp; 1340 fp->f_count++; 1341 fp->f_msgcount++; 1342 mutex_exit(&fp->f_lock); 1343 atomic_inc_uint(&unp_rights); 1344 } 1345 1346 out: 1347 /* Release descriptor references. */ 1348 fdp = (int *)CMSG_DATA(cm); 1349 for (i = 0; i < nfds; i++) { 1350 fd_putfile(*fdp++); 1351 } 1352 1353 if (error == 0) { 1354 if (control->m_flags & M_EXT) { 1355 m_freem(control); 1356 *controlp = control = m_get(M_WAIT, MT_CONTROL); 1357 } 1358 MEXTADD(control, newcm, CMSG_SPACE(nfds * sizeof(file_t *)), 1359 M_MBUF, NULL, NULL); 1360 cm = newcm; 1361 /* 1362 * Adjust message & mbuf to note amount of space 1363 * actually used. 1364 */ 1365 cm->cmsg_len = CMSG_LEN(nfds * sizeof(file_t *)); 1366 control->m_len = CMSG_SPACE(nfds * sizeof(file_t *)); 1367 } 1368 1369 return error; 1370 } 1371 1372 struct mbuf * 1373 unp_addsockcred(struct lwp *l, struct mbuf *control) 1374 { 1375 struct cmsghdr *cmp; 1376 struct sockcred *sc; 1377 struct mbuf *m, *n; 1378 int len, space, i; 1379 1380 len = CMSG_LEN(SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred))); 1381 space = CMSG_SPACE(SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred))); 1382 1383 m = m_get(M_WAIT, MT_CONTROL); 1384 if (space > MLEN) { 1385 if (space > MCLBYTES) 1386 MEXTMALLOC(m, space, M_WAITOK); 1387 else 1388 m_clget(m, M_WAIT); 1389 if ((m->m_flags & M_EXT) == 0) { 1390 m_free(m); 1391 return (control); 1392 } 1393 } 1394 1395 m->m_len = space; 1396 m->m_next = NULL; 1397 cmp = mtod(m, struct cmsghdr *); 1398 sc = (struct sockcred *)CMSG_DATA(cmp); 1399 cmp->cmsg_len = len; 1400 cmp->cmsg_level = SOL_SOCKET; 1401 cmp->cmsg_type = SCM_CREDS; 1402 sc->sc_uid = kauth_cred_getuid(l->l_cred); 1403 sc->sc_euid = kauth_cred_geteuid(l->l_cred); 1404 sc->sc_gid = kauth_cred_getgid(l->l_cred); 1405 sc->sc_egid = kauth_cred_getegid(l->l_cred); 1406 sc->sc_ngroups = kauth_cred_ngroups(l->l_cred); 1407 for (i = 0; i < sc->sc_ngroups; i++) 1408 sc->sc_groups[i] = kauth_cred_group(l->l_cred, i); 1409 1410 /* 1411 * If a control message already exists, append us to the end. 1412 */ 1413 if (control != NULL) { 1414 for (n = control; n->m_next != NULL; n = n->m_next) 1415 ; 1416 n->m_next = m; 1417 } else 1418 control = m; 1419 1420 return (control); 1421 } 1422 1423 int unp_defer, unp_gcing; 1424 extern struct domain unixdomain; 1425 1426 /* 1427 * Comment added long after the fact explaining what's going on here. 1428 * Do a mark-sweep GC of file descriptors on the system, to free up 1429 * any which are caught in flight to an about-to-be-closed socket. 1430 * 1431 * Traditional mark-sweep gc's start at the "root", and mark 1432 * everything reachable from the root (which, in our case would be the 1433 * process table). The mark bits are cleared during the sweep. 1434 * 1435 * XXX For some inexplicable reason (perhaps because the file 1436 * descriptor tables used to live in the u area which could be swapped 1437 * out and thus hard to reach), we do multiple scans over the set of 1438 * descriptors, using use *two* mark bits per object (DEFER and MARK). 1439 * Whenever we find a descriptor which references other descriptors, 1440 * the ones it references are marked with both bits, and we iterate 1441 * over the whole file table until there are no more DEFER bits set. 1442 * We also make an extra pass *before* the GC to clear the mark bits, 1443 * which could have been cleared at almost no cost during the previous 1444 * sweep. 1445 */ 1446 void 1447 unp_gc(void) 1448 { 1449 file_t *fp, *nextfp; 1450 struct socket *so, *so1; 1451 file_t **extra_ref, **fpp; 1452 int nunref, nslots, i; 1453 1454 if (atomic_swap_uint(&unp_gcing, 1) == 1) 1455 return; 1456 1457 restart: 1458 nslots = nfiles * 2; 1459 extra_ref = kmem_alloc(nslots * sizeof(file_t *), KM_SLEEP); 1460 1461 mutex_enter(&filelist_lock); 1462 unp_defer = 0; 1463 1464 /* Clear mark bits */ 1465 LIST_FOREACH(fp, &filehead, f_list) { 1466 atomic_and_uint(&fp->f_flag, ~(FMARK|FDEFER)); 1467 } 1468 1469 /* 1470 * Iterate over the set of descriptors, marking ones believed 1471 * (based on refcount) to be referenced from a process, and 1472 * marking for rescan descriptors which are queued on a socket. 1473 */ 1474 do { 1475 LIST_FOREACH(fp, &filehead, f_list) { 1476 mutex_enter(&fp->f_lock); 1477 if (fp->f_flag & FDEFER) { 1478 atomic_and_uint(&fp->f_flag, ~FDEFER); 1479 unp_defer--; 1480 KASSERT(fp->f_count != 0); 1481 } else { 1482 if (fp->f_count == 0 || 1483 (fp->f_flag & FMARK) || 1484 fp->f_count == fp->f_msgcount) { 1485 mutex_exit(&fp->f_lock); 1486 continue; 1487 } 1488 } 1489 atomic_or_uint(&fp->f_flag, FMARK); 1490 1491 if (fp->f_type != DTYPE_SOCKET || 1492 (so = fp->f_data) == NULL || 1493 so->so_proto->pr_domain != &unixdomain || 1494 (so->so_proto->pr_flags&PR_RIGHTS) == 0) { 1495 mutex_exit(&fp->f_lock); 1496 continue; 1497 } 1498 #ifdef notdef 1499 if (so->so_rcv.sb_flags & SB_LOCK) { 1500 mutex_exit(&fp->f_lock); 1501 mutex_exit(&filelist_lock); 1502 kmem_free(extra_ref, nslots * sizeof(file_t *)); 1503 /* 1504 * This is problematical; it's not clear 1505 * we need to wait for the sockbuf to be 1506 * unlocked (on a uniprocessor, at least), 1507 * and it's also not clear what to do 1508 * if sbwait returns an error due to receipt 1509 * of a signal. If sbwait does return 1510 * an error, we'll go into an infinite 1511 * loop. Delete all of this for now. 1512 */ 1513 (void) sbwait(&so->so_rcv); 1514 goto restart; 1515 } 1516 #endif 1517 mutex_exit(&fp->f_lock); 1518 1519 /* 1520 * XXX Locking a socket with filelist_lock held 1521 * is ugly. filelist_lock can be taken by the 1522 * pagedaemon when reclaiming items from file_cache. 1523 * Socket activity could delay the pagedaemon. 1524 */ 1525 solock(so); 1526 unp_scan(so->so_rcv.sb_mb, unp_mark, 0); 1527 /* 1528 * Mark descriptors referenced from sockets queued 1529 * on the accept queue as well. 1530 */ 1531 if (so->so_options & SO_ACCEPTCONN) { 1532 TAILQ_FOREACH(so1, &so->so_q0, so_qe) { 1533 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1534 } 1535 TAILQ_FOREACH(so1, &so->so_q, so_qe) { 1536 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1537 } 1538 } 1539 sounlock(so); 1540 } 1541 } while (unp_defer); 1542 1543 /* 1544 * Sweep pass. Find unmarked descriptors, and free them. 1545 * 1546 * We grab an extra reference to each of the file table entries 1547 * that are not otherwise accessible and then free the rights 1548 * that are stored in messages on them. 1549 * 1550 * The bug in the original code is a little tricky, so I'll describe 1551 * what's wrong with it here. 1552 * 1553 * It is incorrect to simply unp_discard each entry for f_msgcount 1554 * times -- consider the case of sockets A and B that contain 1555 * references to each other. On a last close of some other socket, 1556 * we trigger a gc since the number of outstanding rights (unp_rights) 1557 * is non-zero. If during the sweep phase the gc code un_discards, 1558 * we end up doing a (full) closef on the descriptor. A closef on A 1559 * results in the following chain. Closef calls soo_close, which 1560 * calls soclose. Soclose calls first (through the switch 1561 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1562 * returns because the previous instance had set unp_gcing, and 1563 * we return all the way back to soclose, which marks the socket 1564 * with SS_NOFDREF, and then calls sofree. Sofree calls sorflush 1565 * to free up the rights that are queued in messages on the socket A, 1566 * i.e., the reference on B. The sorflush calls via the dom_dispose 1567 * switch unp_dispose, which unp_scans with unp_discard. This second 1568 * instance of unp_discard just calls closef on B. 1569 * 1570 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1571 * which results in another closef on A. Unfortunately, A is already 1572 * being closed, and the descriptor has already been marked with 1573 * SS_NOFDREF, and soclose panics at this point. 1574 * 1575 * Here, we first take an extra reference to each inaccessible 1576 * descriptor. Then, if the inaccessible descriptor is a 1577 * socket, we call sorflush in case it is a Unix domain 1578 * socket. After we destroy all the rights carried in 1579 * messages, we do a last closef to get rid of our extra 1580 * reference. This is the last close, and the unp_detach etc 1581 * will shut down the socket. 1582 * 1583 * 91/09/19, bsy@cs.cmu.edu 1584 */ 1585 if (nslots < nfiles) { 1586 mutex_exit(&filelist_lock); 1587 kmem_free(extra_ref, nslots * sizeof(file_t *)); 1588 goto restart; 1589 } 1590 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; fp != 0; 1591 fp = nextfp) { 1592 nextfp = LIST_NEXT(fp, f_list); 1593 mutex_enter(&fp->f_lock); 1594 if (fp->f_count != 0 && 1595 fp->f_count == fp->f_msgcount && !(fp->f_flag & FMARK)) { 1596 *fpp++ = fp; 1597 nunref++; 1598 fp->f_count++; 1599 } 1600 mutex_exit(&fp->f_lock); 1601 } 1602 mutex_exit(&filelist_lock); 1603 1604 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1605 fp = *fpp; 1606 if (fp->f_type == DTYPE_SOCKET) { 1607 so = fp->f_data; 1608 solock(so); 1609 sorflush(fp->f_data); 1610 sounlock(so); 1611 } 1612 } 1613 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1614 closef(*fpp); 1615 } 1616 kmem_free(extra_ref, nslots * sizeof(file_t *)); 1617 atomic_swap_uint(&unp_gcing, 0); 1618 } 1619 1620 void 1621 unp_dispose(struct mbuf *m) 1622 { 1623 1624 if (m) 1625 unp_scan(m, unp_discard, 1); 1626 } 1627 1628 void 1629 unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard) 1630 { 1631 struct mbuf *m; 1632 file_t **rp; 1633 struct cmsghdr *cm; 1634 int i; 1635 int qfds; 1636 1637 while (m0) { 1638 for (m = m0; m; m = m->m_next) { 1639 if (m->m_type == MT_CONTROL && 1640 m->m_len >= sizeof(*cm)) { 1641 cm = mtod(m, struct cmsghdr *); 1642 if (cm->cmsg_level != SOL_SOCKET || 1643 cm->cmsg_type != SCM_RIGHTS) 1644 continue; 1645 qfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) 1646 / sizeof(file_t *); 1647 rp = (file_t **)CMSG_DATA(cm); 1648 for (i = 0; i < qfds; i++) { 1649 file_t *fp = *rp; 1650 if (discard) 1651 *rp = 0; 1652 (*op)(fp); 1653 rp++; 1654 } 1655 break; /* XXX, but saves time */ 1656 } 1657 } 1658 m0 = m0->m_nextpkt; 1659 } 1660 } 1661 1662 void 1663 unp_mark(file_t *fp) 1664 { 1665 1666 if (fp == NULL) 1667 return; 1668 1669 /* If we're already deferred, don't screw up the defer count */ 1670 mutex_enter(&fp->f_lock); 1671 if (fp->f_flag & (FMARK | FDEFER)) { 1672 mutex_exit(&fp->f_lock); 1673 return; 1674 } 1675 1676 /* 1677 * Minimize the number of deferrals... Sockets are the only 1678 * type of descriptor which can hold references to another 1679 * descriptor, so just mark other descriptors, and defer 1680 * unmarked sockets for the next pass. 1681 */ 1682 if (fp->f_type == DTYPE_SOCKET) { 1683 unp_defer++; 1684 KASSERT(fp->f_count != 0); 1685 atomic_or_uint(&fp->f_flag, FDEFER); 1686 } else { 1687 atomic_or_uint(&fp->f_flag, FMARK); 1688 } 1689 mutex_exit(&fp->f_lock); 1690 return; 1691 } 1692 1693 void 1694 unp_discard(file_t *fp) 1695 { 1696 1697 if (fp == NULL) 1698 return; 1699 1700 mutex_enter(&fp->f_lock); 1701 KASSERT(fp->f_count > 0); 1702 fp->f_msgcount--; 1703 mutex_exit(&fp->f_lock); 1704 atomic_dec_uint(&unp_rights); 1705 (void)closef(fp); 1706 } 1707