Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_usrreq.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. 4 * Copyright (c) 2004-2007 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94 32 */ 33 34 /* 35 * UNIX Domain (Local) Sockets 36 * 37 * This is an implementation of UNIX (local) domain sockets. Each socket has 38 * an associated struct unpcb (UNIX protocol control block). Stream sockets 39 * may be connected to 0 or 1 other socket. Datagram sockets may be 40 * connected to 0, 1, or many other sockets. Sockets may be created and 41 * connected in pairs (socketpair(2)), or bound/connected to using the file 42 * system name space. For most purposes, only the receive socket buffer is 43 * used, as sending on one socket delivers directly to the receive socket 44 * buffer of a second socket. 45 * 46 * The implementation is substantially complicated by the fact that 47 * "ancillary data", such as file descriptors or credentials, may be passed 48 * across UNIX domain sockets. The potential for passing UNIX domain sockets 49 * over other UNIX domain sockets requires the implementation of a simple 50 * garbage collector to find and tear down cycles of disconnected sockets. 51 * 52 * TODO: 53 * SEQPACKET, RDM 54 * rethink name space problems 55 * need a proper out-of-band 56 * lock pushdown 57 */ 58 59 #include <sys/cdefs.h> 60 __FBSDID("$FreeBSD$"); 61 62 #include "opt_ddb.h" 63 #include "opt_mac.h" 64 65 #include <sys/param.h> 66 #include <sys/domain.h> 67 #include <sys/fcntl.h> 68 #include <sys/malloc.h> /* XXX must be before <sys/file.h> */ 69 #include <sys/eventhandler.h> 70 #include <sys/file.h> 71 #include <sys/filedesc.h> 72 #include <sys/jail.h> 73 #include <sys/kernel.h> 74 #include <sys/lock.h> 75 #include <sys/mbuf.h> 76 #include <sys/mount.h> 77 #include <sys/mutex.h> 78 #include <sys/namei.h> 79 #include <sys/proc.h> 80 #include <sys/protosw.h> 81 #include <sys/resourcevar.h> 82 #include <sys/rwlock.h> 83 #include <sys/socket.h> 84 #include <sys/socketvar.h> 85 #include <sys/signalvar.h> 86 #include <sys/stat.h> 87 #include <sys/sx.h> 88 #include <sys/sysctl.h> 89 #include <sys/systm.h> 90 #include <sys/taskqueue.h> 91 #include <sys/un.h> 92 #include <sys/unpcb.h> 93 #include <sys/vnode.h> 94 95 #ifdef DDB 96 #include <ddb/ddb.h> 97 #endif 98 99 #include <security/mac/mac_framework.h> 100 101 #include <vm/uma.h> 102 103 static uma_zone_t unp_zone; 104 static unp_gen_t unp_gencnt; 105 static u_int unp_count; /* Count of local sockets. */ 106 static ino_t unp_ino; /* Prototype for fake inode numbers. */ 107 static int unp_rights; /* File descriptors in flight. */ 108 static struct unp_head unp_shead; /* List of local stream sockets. */ 109 static struct unp_head unp_dhead; /* List of local datagram sockets. */ 110 111 static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; 112 113 /* 114 * Garbage collection of cyclic file descriptor/socket references occurs 115 * asynchronously in a taskqueue context in order to avoid recursion and 116 * reentrance in the UNIX domain socket, file descriptor, and socket layer 117 * code. See unp_gc() for a full description. 118 */ 119 static struct task unp_gc_task; 120 121 /* 122 * Both send and receive buffers are allocated PIPSIZ bytes of buffering for 123 * stream sockets, although the total for sender and receiver is actually 124 * only PIPSIZ. 125 * 126 * Datagram sockets really use the sendspace as the maximum datagram size, 127 * and don't really want to reserve the sendspace. Their recvspace should be 128 * large enough for at least one max-size datagram plus address. 129 */ 130 #ifndef PIPSIZ 131 #define PIPSIZ 8192 132 #endif 133 static u_long unpst_sendspace = PIPSIZ; 134 static u_long unpst_recvspace = PIPSIZ; 135 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 136 static u_long unpdg_recvspace = 4*1024; 137 138 SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain"); 139 SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0, "SOCK_STREAM"); 140 SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM"); 141 142 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 143 &unpst_sendspace, 0, ""); 144 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 145 &unpst_recvspace, 0, ""); 146 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 147 &unpdg_sendspace, 0, ""); 148 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 149 &unpdg_recvspace, 0, ""); 150 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 151 152 /*- 153 * Locking and synchronization: 154 * 155 * The global UNIX domain socket rwlock (unp_global_rwlock) protects all 156 * global variables, including the linked lists tracking the set of allocated 157 * UNIX domain sockets. The global rwlock also serves to prevent deadlock 158 * when more than one PCB lock is acquired at a time (i.e., during 159 * connect()). Finally, the global rwlock protects uncounted references from 160 * vnodes to sockets bound to those vnodes: to safely dereference the 161 * v_socket pointer, the global rwlock must be held while a full reference is 162 * acquired. 163 * 164 * UNIX domain sockets each have an unpcb hung off of their so_pcb pointer, 165 * allocated in pru_attach() and freed in pru_detach(). The validity of that 166 * pointer is an invariant, so no lock is required to dereference the so_pcb 167 * pointer if a valid socket reference is held by the caller. In practice, 168 * this is always true during operations performed on a socket. Each unpcb 169 * has a back-pointer to its socket, unp_socket, which will be stable under 170 * the same circumstances. 171 * 172 * This pointer may only be safely dereferenced as long as a valid reference 173 * to the unpcb is held. Typically, this reference will be from the socket, 174 * or from another unpcb when the referring unpcb's lock is held (in order 175 * that the reference not be invalidated during use). For example, to follow 176 * unp->unp_conn->unp_socket, you need unlock the lock on unp, not unp_conn, 177 * as unp_socket remains valid as long as the reference to unp_conn is valid. 178 * 179 * Fields of unpcbss are locked using a per-unpcb lock, unp_mtx. Individual 180 * atomic reads without the lock may be performed "lockless", but more 181 * complex reads and read-modify-writes require the mutex to be held. No 182 * lock order is defined between unpcb locks -- multiple unpcb locks may be 183 * acquired at the same time only when holding the global UNIX domain socket 184 * rwlock exclusively, which prevents deadlocks. 185 * 186 * Blocking with UNIX domain sockets is a tricky issue: unlike most network 187 * protocols, bind() is a non-atomic operation, and connect() requires 188 * potential sleeping in the protocol, due to potentially waiting on local or 189 * distributed file systems. We try to separate "lookup" operations, which 190 * may sleep, and the IPC operations themselves, which typically can occur 191 * with relative atomicity as locks can be held over the entire operation. 192 * 193 * Another tricky issue is simultaneous multi-threaded or multi-process 194 * access to a single UNIX domain socket. These are handled by the flags 195 * UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or 196 * binding, both of which involve dropping UNIX domain socket locks in order 197 * to perform namei() and other file system operations. 198 */ 199 static struct rwlock unp_global_rwlock; 200 201 #define UNP_GLOBAL_LOCK_INIT() rw_init(&unp_global_rwlock, \ 202 "unp_global_rwlock") 203 204 #define UNP_GLOBAL_LOCK_ASSERT() rw_assert(&unp_global_rwlock, \ 205 RA_LOCKED) 206 #define UNP_GLOBAL_UNLOCK_ASSERT() rw_assert(&unp_global_rwlock, \ 207 RA_UNLOCKED) 208 209 #define UNP_GLOBAL_WLOCK() rw_wlock(&unp_global_rwlock) 210 #define UNP_GLOBAL_WUNLOCK() rw_wunlock(&unp_global_rwlock) 211 #define UNP_GLOBAL_WLOCK_ASSERT() rw_assert(&unp_global_rwlock, \ 212 RA_WLOCKED) 213 #define UNP_GLOBAL_WOWNED() rw_wowned(&unp_global_rwlock) 214 215 #define UNP_GLOBAL_RLOCK() rw_rlock(&unp_global_rwlock) 216 #define UNP_GLOBAL_RUNLOCK() rw_runlock(&unp_global_rwlock) 217 #define UNP_GLOBAL_RLOCK_ASSERT() rw_assert(&unp_global_rwlock, \ 218 RA_RLOCKED) 219 220 #define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \ 221 "unp_mtx", "unp_mtx", \ 222 MTX_DUPOK|MTX_DEF|MTX_RECURSE) 223 #define UNP_PCB_LOCK_DESTROY(unp) mtx_destroy(&(unp)->unp_mtx) 224 #define UNP_PCB_LOCK(unp) mtx_lock(&(unp)->unp_mtx) 225 #define UNP_PCB_UNLOCK(unp) mtx_unlock(&(unp)->unp_mtx) 226 #define UNP_PCB_LOCK_ASSERT(unp) mtx_assert(&(unp)->unp_mtx, MA_OWNED) 227 228 static int unp_connect(struct socket *, struct sockaddr *, 229 struct thread *); 230 static int unp_connect2(struct socket *so, struct socket *so2, int); 231 static void unp_disconnect(struct unpcb *unp, struct unpcb *unp2); 232 static void unp_shutdown(struct unpcb *); 233 static void unp_drop(struct unpcb *, int); 234 static void unp_gc(__unused void *, int); 235 static void unp_scan(struct mbuf *, void (*)(struct file *)); 236 static void unp_mark(struct file *); 237 static void unp_discard(struct file *); 238 static void unp_freerights(struct file **, int); 239 static int unp_internalize(struct mbuf **, struct thread *); 240 static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *); 241 242 /* 243 * Definitions of protocols supported in the LOCAL domain. 244 */ 245 static struct domain localdomain; 246 static struct protosw localsw[] = { 247 { 248 .pr_type = SOCK_STREAM, 249 .pr_domain = &localdomain, 250 .pr_flags = PR_CONNREQUIRED|PR_WANTRCVD|PR_RIGHTS, 251 .pr_ctloutput = &uipc_ctloutput, 252 .pr_usrreqs = &uipc_usrreqs 253 }, 254 { 255 .pr_type = SOCK_DGRAM, 256 .pr_domain = &localdomain, 257 .pr_flags = PR_ATOMIC|PR_ADDR|PR_RIGHTS, 258 .pr_usrreqs = &uipc_usrreqs 259 }, 260 }; 261 262 static struct domain localdomain = { 263 .dom_family = AF_LOCAL, 264 .dom_name = "local", 265 .dom_init = unp_init, 266 .dom_externalize = unp_externalize, 267 .dom_dispose = unp_dispose, 268 .dom_protosw = localsw, 269 .dom_protoswNPROTOSW = &localsw[sizeof(localsw)/sizeof(localsw[0])] 270 }; 271 DOMAIN_SET(local); 272 273 static void 274 uipc_abort(struct socket *so) 275 { 276 struct unpcb *unp, *unp2; 277 278 unp = sotounpcb(so); 279 KASSERT(unp != NULL, ("uipc_abort: unp == NULL")); 280 281 UNP_GLOBAL_WLOCK(); 282 UNP_PCB_LOCK(unp); 283 unp2 = unp->unp_conn; 284 if (unp2 != NULL) { 285 UNP_PCB_LOCK(unp2); 286 unp_drop(unp2, ECONNABORTED); 287 UNP_PCB_UNLOCK(unp2); 288 } 289 UNP_PCB_UNLOCK(unp); 290 UNP_GLOBAL_WUNLOCK(); 291 } 292 293 static int 294 uipc_accept(struct socket *so, struct sockaddr **nam) 295 { 296 struct unpcb *unp, *unp2; 297 const struct sockaddr *sa; 298 299 /* 300 * Pass back name of connected socket, if it was bound and we are 301 * still connected (our peer may have closed already!). 302 */ 303 unp = sotounpcb(so); 304 KASSERT(unp != NULL, ("uipc_accept: unp == NULL")); 305 306 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 307 UNP_GLOBAL_RLOCK(); 308 unp2 = unp->unp_conn; 309 if (unp2 != NULL && unp2->unp_addr != NULL) { 310 UNP_PCB_LOCK(unp2); 311 sa = (struct sockaddr *) unp2->unp_addr; 312 bcopy(sa, *nam, sa->sa_len); 313 UNP_PCB_UNLOCK(unp2); 314 } else { 315 sa = &sun_noname; 316 bcopy(sa, *nam, sa->sa_len); 317 } 318 UNP_GLOBAL_RUNLOCK(); 319 return (0); 320 } 321 322 static int 323 uipc_attach(struct socket *so, int proto, struct thread *td) 324 { 325 u_long sendspace, recvspace; 326 struct unpcb *unp; 327 int error, locked; 328 329 KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL")); 330 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 331 switch (so->so_type) { 332 case SOCK_STREAM: 333 sendspace = unpst_sendspace; 334 recvspace = unpst_recvspace; 335 break; 336 337 case SOCK_DGRAM: 338 sendspace = unpdg_sendspace; 339 recvspace = unpdg_recvspace; 340 break; 341 342 default: 343 panic("uipc_attach"); 344 } 345 error = soreserve(so, sendspace, recvspace); 346 if (error) 347 return (error); 348 } 349 unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO); 350 if (unp == NULL) 351 return (ENOBUFS); 352 LIST_INIT(&unp->unp_refs); 353 UNP_PCB_LOCK_INIT(unp); 354 unp->unp_socket = so; 355 so->so_pcb = unp; 356 unp->unp_refcount = 1; 357 358 /* 359 * uipc_attach() may be called indirectly from within the UNIX domain 360 * socket code via sonewconn() in unp_connect(). Since rwlocks can 361 * not be recursed, we do the closest thing. 362 */ 363 locked = 0; 364 if (!UNP_GLOBAL_WOWNED()) { 365 UNP_GLOBAL_WLOCK(); 366 locked = 1; 367 } 368 unp->unp_gencnt = ++unp_gencnt; 369 unp_count++; 370 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead : &unp_shead, 371 unp, unp_link); 372 if (locked) 373 UNP_GLOBAL_WUNLOCK(); 374 375 return (0); 376 } 377 378 static int 379 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 380 { 381 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 382 struct vattr vattr; 383 int error, namelen, vfslocked; 384 struct nameidata nd; 385 struct unpcb *unp; 386 struct vnode *vp; 387 struct mount *mp; 388 char *buf; 389 390 unp = sotounpcb(so); 391 KASSERT(unp != NULL, ("uipc_bind: unp == NULL")); 392 393 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 394 if (namelen <= 0) 395 return (EINVAL); 396 397 /* 398 * We don't allow simultaneous bind() calls on a single UNIX domain 399 * socket, so flag in-progress operations, and return an error if an 400 * operation is already in progress. 401 * 402 * Historically, we have not allowed a socket to be rebound, so this 403 * also returns an error. Not allowing re-binding simplifies the 404 * implementation and avoids a great many possible failure modes. 405 */ 406 UNP_PCB_LOCK(unp); 407 if (unp->unp_vnode != NULL) { 408 UNP_PCB_UNLOCK(unp); 409 return (EINVAL); 410 } 411 if (unp->unp_flags & UNP_BINDING) { 412 UNP_PCB_UNLOCK(unp); 413 return (EALREADY); 414 } 415 unp->unp_flags |= UNP_BINDING; 416 UNP_PCB_UNLOCK(unp); 417 418 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 419 strlcpy(buf, soun->sun_path, namelen + 1); 420 421 restart: 422 vfslocked = 0; 423 NDINIT(&nd, CREATE, MPSAFE | NOFOLLOW | LOCKPARENT | SAVENAME, 424 UIO_SYSSPACE, buf, td); 425 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 426 error = namei(&nd); 427 if (error) 428 goto error; 429 vp = nd.ni_vp; 430 vfslocked = NDHASGIANT(&nd); 431 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 432 NDFREE(&nd, NDF_ONLY_PNBUF); 433 if (nd.ni_dvp == vp) 434 vrele(nd.ni_dvp); 435 else 436 vput(nd.ni_dvp); 437 if (vp != NULL) { 438 vrele(vp); 439 error = EADDRINUSE; 440 goto error; 441 } 442 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 443 if (error) 444 goto error; 445 VFS_UNLOCK_GIANT(vfslocked); 446 goto restart; 447 } 448 VATTR_NULL(&vattr); 449 vattr.va_type = VSOCK; 450 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 451 #ifdef MAC 452 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 453 &vattr); 454 #endif 455 if (error == 0) { 456 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 457 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 458 } 459 NDFREE(&nd, NDF_ONLY_PNBUF); 460 vput(nd.ni_dvp); 461 if (error) { 462 vn_finished_write(mp); 463 goto error; 464 } 465 vp = nd.ni_vp; 466 ASSERT_VOP_ELOCKED(vp, "uipc_bind"); 467 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 468 469 UNP_GLOBAL_WLOCK(); 470 UNP_PCB_LOCK(unp); 471 vp->v_socket = unp->unp_socket; 472 unp->unp_vnode = vp; 473 unp->unp_addr = soun; 474 unp->unp_flags &= ~UNP_BINDING; 475 UNP_PCB_UNLOCK(unp); 476 UNP_GLOBAL_WUNLOCK(); 477 VOP_UNLOCK(vp, 0, td); 478 vn_finished_write(mp); 479 VFS_UNLOCK_GIANT(vfslocked); 480 free(buf, M_TEMP); 481 return (0); 482 483 error: 484 VFS_UNLOCK_GIANT(vfslocked); 485 UNP_PCB_LOCK(unp); 486 unp->unp_flags &= ~UNP_BINDING; 487 UNP_PCB_UNLOCK(unp); 488 free(buf, M_TEMP); 489 return (error); 490 } 491 492 static int 493 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 494 { 495 int error; 496 497 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 498 UNP_GLOBAL_WLOCK(); 499 error = unp_connect(so, nam, td); 500 UNP_GLOBAL_WUNLOCK(); 501 return (error); 502 } 503 504 static void 505 uipc_close(struct socket *so) 506 { 507 struct unpcb *unp, *unp2; 508 509 unp = sotounpcb(so); 510 KASSERT(unp != NULL, ("uipc_close: unp == NULL")); 511 512 UNP_GLOBAL_WLOCK(); 513 UNP_PCB_LOCK(unp); 514 unp2 = unp->unp_conn; 515 if (unp2 != NULL) { 516 UNP_PCB_LOCK(unp2); 517 unp_disconnect(unp, unp2); 518 UNP_PCB_UNLOCK(unp2); 519 } 520 UNP_PCB_UNLOCK(unp); 521 UNP_GLOBAL_WUNLOCK(); 522 } 523 524 int 525 uipc_connect2(struct socket *so1, struct socket *so2) 526 { 527 struct unpcb *unp, *unp2; 528 int error; 529 530 UNP_GLOBAL_WLOCK(); 531 unp = so1->so_pcb; 532 KASSERT(unp != NULL, ("uipc_connect2: unp == NULL")); 533 UNP_PCB_LOCK(unp); 534 unp2 = so2->so_pcb; 535 KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL")); 536 UNP_PCB_LOCK(unp2); 537 error = unp_connect2(so1, so2, PRU_CONNECT2); 538 UNP_PCB_UNLOCK(unp2); 539 UNP_PCB_UNLOCK(unp); 540 UNP_GLOBAL_WUNLOCK(); 541 return (error); 542 } 543 544 /* control is EOPNOTSUPP */ 545 546 static void 547 uipc_detach(struct socket *so) 548 { 549 struct unpcb *unp, *unp2; 550 struct sockaddr_un *saved_unp_addr; 551 struct vnode *vp; 552 int freeunp, local_unp_rights; 553 554 unp = sotounpcb(so); 555 KASSERT(unp != NULL, ("uipc_detach: unp == NULL")); 556 557 UNP_GLOBAL_WLOCK(); 558 UNP_PCB_LOCK(unp); 559 560 LIST_REMOVE(unp, unp_link); 561 unp->unp_gencnt = ++unp_gencnt; 562 --unp_count; 563 564 /* 565 * XXXRW: Should assert vp->v_socket == so. 566 */ 567 if ((vp = unp->unp_vnode) != NULL) { 568 unp->unp_vnode->v_socket = NULL; 569 unp->unp_vnode = NULL; 570 } 571 unp2 = unp->unp_conn; 572 if (unp2 != NULL) { 573 UNP_PCB_LOCK(unp2); 574 unp_disconnect(unp, unp2); 575 UNP_PCB_UNLOCK(unp2); 576 } 577 578 /* 579 * We hold the global lock, so it's OK to acquire multiple pcb locks 580 * at a time. 581 */ 582 while (!LIST_EMPTY(&unp->unp_refs)) { 583 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 584 585 UNP_PCB_LOCK(ref); 586 unp_drop(ref, ECONNRESET); 587 UNP_PCB_UNLOCK(ref); 588 } 589 UNP_GLOBAL_WUNLOCK(); 590 unp->unp_socket->so_pcb = NULL; 591 local_unp_rights = unp_rights; 592 saved_unp_addr = unp->unp_addr; 593 unp->unp_addr = NULL; 594 unp->unp_refcount--; 595 freeunp = (unp->unp_refcount == 0); 596 if (saved_unp_addr != NULL) 597 FREE(saved_unp_addr, M_SONAME); 598 if (freeunp) { 599 UNP_PCB_LOCK_DESTROY(unp); 600 uma_zfree(unp_zone, unp); 601 } else 602 UNP_PCB_UNLOCK(unp); 603 if (vp) { 604 int vfslocked; 605 606 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 607 vrele(vp); 608 VFS_UNLOCK_GIANT(vfslocked); 609 } 610 if (local_unp_rights) 611 taskqueue_enqueue(taskqueue_thread, &unp_gc_task); 612 } 613 614 static int 615 uipc_disconnect(struct socket *so) 616 { 617 struct unpcb *unp, *unp2; 618 619 unp = sotounpcb(so); 620 KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL")); 621 622 UNP_GLOBAL_WLOCK(); 623 UNP_PCB_LOCK(unp); 624 unp2 = unp->unp_conn; 625 if (unp2 != NULL) { 626 UNP_PCB_LOCK(unp2); 627 unp_disconnect(unp, unp2); 628 UNP_PCB_UNLOCK(unp2); 629 } 630 UNP_PCB_UNLOCK(unp); 631 UNP_GLOBAL_WUNLOCK(); 632 return (0); 633 } 634 635 static int 636 uipc_listen(struct socket *so, int backlog, struct thread *td) 637 { 638 struct unpcb *unp; 639 int error; 640 641 unp = sotounpcb(so); 642 KASSERT(unp != NULL, ("uipc_listen: unp == NULL")); 643 644 UNP_PCB_LOCK(unp); 645 if (unp->unp_vnode == NULL) { 646 UNP_PCB_UNLOCK(unp); 647 return (EINVAL); 648 } 649 650 SOCK_LOCK(so); 651 error = solisten_proto_check(so); 652 if (error == 0) { 653 cru2x(td->td_ucred, &unp->unp_peercred); 654 unp->unp_flags |= UNP_HAVEPCCACHED; 655 solisten_proto(so, backlog); 656 } 657 SOCK_UNLOCK(so); 658 UNP_PCB_UNLOCK(unp); 659 return (error); 660 } 661 662 static int 663 uipc_peeraddr(struct socket *so, struct sockaddr **nam) 664 { 665 struct unpcb *unp, *unp2; 666 const struct sockaddr *sa; 667 668 unp = sotounpcb(so); 669 KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL")); 670 671 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 672 UNP_PCB_LOCK(unp); 673 /* 674 * XXX: It seems that this test always fails even when connection is 675 * established. So, this else clause is added as workaround to 676 * return PF_LOCAL sockaddr. 677 */ 678 unp2 = unp->unp_conn; 679 if (unp2 != NULL) { 680 UNP_PCB_LOCK(unp2); 681 if (unp2->unp_addr != NULL) 682 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 683 else 684 sa = &sun_noname; 685 bcopy(sa, *nam, sa->sa_len); 686 UNP_PCB_UNLOCK(unp2); 687 } else { 688 sa = &sun_noname; 689 bcopy(sa, *nam, sa->sa_len); 690 } 691 UNP_PCB_UNLOCK(unp); 692 return (0); 693 } 694 695 static int 696 uipc_rcvd(struct socket *so, int flags) 697 { 698 struct unpcb *unp, *unp2; 699 struct socket *so2; 700 u_int mbcnt, sbcc; 701 u_long newhiwat; 702 703 unp = sotounpcb(so); 704 KASSERT(unp != NULL, ("uipc_rcvd: unp == NULL")); 705 706 if (so->so_type == SOCK_DGRAM) 707 panic("uipc_rcvd DGRAM?"); 708 709 if (so->so_type != SOCK_STREAM) 710 panic("uipc_rcvd unknown socktype"); 711 712 /* 713 * Adjust backpressure on sender and wakeup any waiting to write. 714 * 715 * The unp lock is acquired to maintain the validity of the unp_conn 716 * pointer; no lock on unp2 is required as unp2->unp_socket will be 717 * static as long as we don't permit unp2 to disconnect from unp, 718 * which is prevented by the lock on unp. We cache values from 719 * so_rcv to avoid holding the so_rcv lock over the entire 720 * transaction on the remote so_snd. 721 */ 722 SOCKBUF_LOCK(&so->so_rcv); 723 mbcnt = so->so_rcv.sb_mbcnt; 724 sbcc = so->so_rcv.sb_cc; 725 SOCKBUF_UNLOCK(&so->so_rcv); 726 UNP_PCB_LOCK(unp); 727 unp2 = unp->unp_conn; 728 if (unp2 == NULL) { 729 UNP_PCB_UNLOCK(unp); 730 return (0); 731 } 732 so2 = unp2->unp_socket; 733 SOCKBUF_LOCK(&so2->so_snd); 734 so2->so_snd.sb_mbmax += unp->unp_mbcnt - mbcnt; 735 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - sbcc; 736 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, 737 newhiwat, RLIM_INFINITY); 738 sowwakeup_locked(so2); 739 unp->unp_mbcnt = mbcnt; 740 unp->unp_cc = sbcc; 741 UNP_PCB_UNLOCK(unp); 742 return (0); 743 } 744 745 /* pru_rcvoob is EOPNOTSUPP */ 746 747 static int 748 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 749 struct mbuf *control, struct thread *td) 750 { 751 struct unpcb *unp, *unp2; 752 struct socket *so2; 753 u_int mbcnt, sbcc; 754 u_long newhiwat; 755 int error = 0; 756 757 unp = sotounpcb(so); 758 KASSERT(unp != NULL, ("uipc_send: unp == NULL")); 759 760 if (flags & PRUS_OOB) { 761 error = EOPNOTSUPP; 762 goto release; 763 } 764 765 if (control != NULL && (error = unp_internalize(&control, td))) 766 goto release; 767 768 if ((nam != NULL) || (flags & PRUS_EOF)) 769 UNP_GLOBAL_WLOCK(); 770 else 771 UNP_GLOBAL_RLOCK(); 772 773 switch (so->so_type) { 774 case SOCK_DGRAM: 775 { 776 const struct sockaddr *from; 777 778 unp2 = unp->unp_conn; 779 if (nam != NULL) { 780 UNP_GLOBAL_WLOCK_ASSERT(); 781 if (unp2 != NULL) { 782 error = EISCONN; 783 break; 784 } 785 error = unp_connect(so, nam, td); 786 if (error) 787 break; 788 unp2 = unp->unp_conn; 789 } 790 /* 791 * Because connect() and send() are non-atomic in a sendto() 792 * with a target address, it's possible that the socket will 793 * have disconnected before the send() can run. In that case 794 * return the slightly counter-intuitive but otherwise 795 * correct error that the socket is not connected. 796 */ 797 if (unp2 == NULL) { 798 error = ENOTCONN; 799 break; 800 } 801 /* Lockless read. */ 802 if (unp2->unp_flags & UNP_WANTCRED) 803 control = unp_addsockcred(td, control); 804 UNP_PCB_LOCK(unp); 805 if (unp->unp_addr != NULL) 806 from = (struct sockaddr *)unp->unp_addr; 807 else 808 from = &sun_noname; 809 so2 = unp2->unp_socket; 810 SOCKBUF_LOCK(&so2->so_rcv); 811 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 812 sorwakeup_locked(so2); 813 m = NULL; 814 control = NULL; 815 } else { 816 SOCKBUF_UNLOCK(&so2->so_rcv); 817 error = ENOBUFS; 818 } 819 if (nam != NULL) { 820 UNP_GLOBAL_WLOCK_ASSERT(); 821 UNP_PCB_LOCK(unp2); 822 unp_disconnect(unp, unp2); 823 UNP_PCB_UNLOCK(unp2); 824 } 825 UNP_PCB_UNLOCK(unp); 826 break; 827 } 828 829 case SOCK_STREAM: 830 /* 831 * Connect if not connected yet. 832 * 833 * Note: A better implementation would complain if not equal 834 * to the peer's address. 835 */ 836 if ((so->so_state & SS_ISCONNECTED) == 0) { 837 if (nam != NULL) { 838 UNP_GLOBAL_WLOCK_ASSERT(); 839 error = unp_connect(so, nam, td); 840 if (error) 841 break; /* XXX */ 842 } else { 843 error = ENOTCONN; 844 break; 845 } 846 } 847 848 /* Lockless read. */ 849 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 850 error = EPIPE; 851 break; 852 } 853 /* 854 * Because connect() and send() are non-atomic in a sendto() 855 * with a target address, it's possible that the socket will 856 * have disconnected before the send() can run. In that case 857 * return the slightly counter-intuitive but otherwise 858 * correct error that the socket is not connected. 859 * 860 * Locking here must be done carefully: the global lock 861 * prevents interconnections between unpcbs from changing, so 862 * we can traverse from unp to unp2 without acquiring unp's 863 * lock. Socket buffer locks follow unpcb locks, so we can 864 * acquire both remote and lock socket buffer locks. 865 */ 866 unp2 = unp->unp_conn; 867 if (unp2 == NULL) { 868 error = ENOTCONN; 869 break; 870 } 871 so2 = unp2->unp_socket; 872 UNP_PCB_LOCK(unp2); 873 SOCKBUF_LOCK(&so2->so_rcv); 874 if (unp2->unp_flags & UNP_WANTCRED) { 875 /* 876 * Credentials are passed only once on SOCK_STREAM. 877 */ 878 unp2->unp_flags &= ~UNP_WANTCRED; 879 control = unp_addsockcred(td, control); 880 } 881 /* 882 * Send to paired receive port, and then reduce send buffer 883 * hiwater marks to maintain backpressure. Wake up readers. 884 */ 885 if (control != NULL) { 886 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 887 control = NULL; 888 } else 889 sbappend_locked(&so2->so_rcv, m); 890 mbcnt = so2->so_rcv.sb_mbcnt - unp2->unp_mbcnt; 891 unp2->unp_mbcnt = so2->so_rcv.sb_mbcnt; 892 sbcc = so2->so_rcv.sb_cc; 893 sorwakeup_locked(so2); 894 895 SOCKBUF_LOCK(&so->so_snd); 896 newhiwat = so->so_snd.sb_hiwat - (sbcc - unp2->unp_cc); 897 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 898 newhiwat, RLIM_INFINITY); 899 so->so_snd.sb_mbmax -= mbcnt; 900 SOCKBUF_UNLOCK(&so->so_snd); 901 unp2->unp_cc = sbcc; 902 UNP_PCB_UNLOCK(unp2); 903 m = NULL; 904 break; 905 906 default: 907 panic("uipc_send unknown socktype"); 908 } 909 910 /* 911 * SEND_EOF is equivalent to a SEND followed by a SHUTDOWN. 912 */ 913 if (flags & PRUS_EOF) { 914 UNP_PCB_LOCK(unp); 915 socantsendmore(so); 916 unp_shutdown(unp); 917 UNP_PCB_UNLOCK(unp); 918 } 919 920 if ((nam != NULL) || (flags & PRUS_EOF)) 921 UNP_GLOBAL_WUNLOCK(); 922 else 923 UNP_GLOBAL_RUNLOCK(); 924 925 if (control != NULL && error != 0) 926 unp_dispose(control); 927 928 release: 929 if (control != NULL) 930 m_freem(control); 931 if (m != NULL) 932 m_freem(m); 933 return (error); 934 } 935 936 static int 937 uipc_sense(struct socket *so, struct stat *sb) 938 { 939 struct unpcb *unp, *unp2; 940 struct socket *so2; 941 942 unp = sotounpcb(so); 943 KASSERT(unp != NULL, ("uipc_sense: unp == NULL")); 944 945 sb->st_blksize = so->so_snd.sb_hiwat; 946 UNP_GLOBAL_RLOCK(); 947 UNP_PCB_LOCK(unp); 948 unp2 = unp->unp_conn; 949 if (so->so_type == SOCK_STREAM && unp2 != NULL) { 950 so2 = unp2->unp_socket; 951 sb->st_blksize += so2->so_rcv.sb_cc; 952 } 953 sb->st_dev = NODEV; 954 if (unp->unp_ino == 0) 955 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 956 sb->st_ino = unp->unp_ino; 957 UNP_PCB_UNLOCK(unp); 958 UNP_GLOBAL_RUNLOCK(); 959 return (0); 960 } 961 962 static int 963 uipc_shutdown(struct socket *so) 964 { 965 struct unpcb *unp; 966 967 unp = sotounpcb(so); 968 KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL")); 969 970 UNP_GLOBAL_WLOCK(); 971 UNP_PCB_LOCK(unp); 972 socantsendmore(so); 973 unp_shutdown(unp); 974 UNP_PCB_UNLOCK(unp); 975 UNP_GLOBAL_WUNLOCK(); 976 return (0); 977 } 978 979 static int 980 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 981 { 982 struct unpcb *unp; 983 const struct sockaddr *sa; 984 985 unp = sotounpcb(so); 986 KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL")); 987 988 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 989 UNP_PCB_LOCK(unp); 990 if (unp->unp_addr != NULL) 991 sa = (struct sockaddr *) unp->unp_addr; 992 else 993 sa = &sun_noname; 994 bcopy(sa, *nam, sa->sa_len); 995 UNP_PCB_UNLOCK(unp); 996 return (0); 997 } 998 999 struct pr_usrreqs uipc_usrreqs = { 1000 .pru_abort = uipc_abort, 1001 .pru_accept = uipc_accept, 1002 .pru_attach = uipc_attach, 1003 .pru_bind = uipc_bind, 1004 .pru_connect = uipc_connect, 1005 .pru_connect2 = uipc_connect2, 1006 .pru_detach = uipc_detach, 1007 .pru_disconnect = uipc_disconnect, 1008 .pru_listen = uipc_listen, 1009 .pru_peeraddr = uipc_peeraddr, 1010 .pru_rcvd = uipc_rcvd, 1011 .pru_send = uipc_send, 1012 .pru_sense = uipc_sense, 1013 .pru_shutdown = uipc_shutdown, 1014 .pru_sockaddr = uipc_sockaddr, 1015 .pru_close = uipc_close, 1016 }; 1017 1018 int 1019 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 1020 { 1021 struct unpcb *unp; 1022 struct xucred xu; 1023 int error, optval; 1024 1025 if (sopt->sopt_level != 0) 1026 return (EINVAL); 1027 1028 unp = sotounpcb(so); 1029 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL")); 1030 error = 0; 1031 switch (sopt->sopt_dir) { 1032 case SOPT_GET: 1033 switch (sopt->sopt_name) { 1034 case LOCAL_PEERCRED: 1035 UNP_PCB_LOCK(unp); 1036 if (unp->unp_flags & UNP_HAVEPC) 1037 xu = unp->unp_peercred; 1038 else { 1039 if (so->so_type == SOCK_STREAM) 1040 error = ENOTCONN; 1041 else 1042 error = EINVAL; 1043 } 1044 UNP_PCB_UNLOCK(unp); 1045 if (error == 0) 1046 error = sooptcopyout(sopt, &xu, sizeof(xu)); 1047 break; 1048 1049 case LOCAL_CREDS: 1050 /* Unocked read. */ 1051 optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0; 1052 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1053 break; 1054 1055 case LOCAL_CONNWAIT: 1056 /* Unocked read. */ 1057 optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0; 1058 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1059 break; 1060 1061 default: 1062 error = EOPNOTSUPP; 1063 break; 1064 } 1065 break; 1066 1067 case SOPT_SET: 1068 switch (sopt->sopt_name) { 1069 case LOCAL_CREDS: 1070 case LOCAL_CONNWAIT: 1071 error = sooptcopyin(sopt, &optval, sizeof(optval), 1072 sizeof(optval)); 1073 if (error) 1074 break; 1075 1076 #define OPTSET(bit) do { \ 1077 UNP_PCB_LOCK(unp); \ 1078 if (optval) \ 1079 unp->unp_flags |= bit; \ 1080 else \ 1081 unp->unp_flags &= ~bit; \ 1082 UNP_PCB_UNLOCK(unp); \ 1083 } while (0) 1084 1085 switch (sopt->sopt_name) { 1086 case LOCAL_CREDS: 1087 OPTSET(UNP_WANTCRED); 1088 break; 1089 1090 case LOCAL_CONNWAIT: 1091 OPTSET(UNP_CONNWAIT); 1092 break; 1093 1094 default: 1095 break; 1096 } 1097 break; 1098 #undef OPTSET 1099 default: 1100 error = ENOPROTOOPT; 1101 break; 1102 } 1103 break; 1104 1105 default: 1106 error = EOPNOTSUPP; 1107 break; 1108 } 1109 return (error); 1110 } 1111 1112 static int 1113 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1114 { 1115 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 1116 struct vnode *vp; 1117 struct socket *so2, *so3; 1118 struct unpcb *unp, *unp2, *unp3; 1119 int error, len, vfslocked; 1120 struct nameidata nd; 1121 char buf[SOCK_MAXADDRLEN]; 1122 struct sockaddr *sa; 1123 1124 UNP_GLOBAL_WLOCK_ASSERT(); 1125 1126 unp = sotounpcb(so); 1127 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1128 1129 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 1130 if (len <= 0) 1131 return (EINVAL); 1132 strlcpy(buf, soun->sun_path, len + 1); 1133 1134 UNP_PCB_LOCK(unp); 1135 if (unp->unp_flags & UNP_CONNECTING) { 1136 UNP_PCB_UNLOCK(unp); 1137 return (EALREADY); 1138 } 1139 UNP_GLOBAL_WUNLOCK(); 1140 unp->unp_flags |= UNP_CONNECTING; 1141 UNP_PCB_UNLOCK(unp); 1142 1143 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 1144 NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, 1145 td); 1146 error = namei(&nd); 1147 if (error) 1148 vp = NULL; 1149 else 1150 vp = nd.ni_vp; 1151 ASSERT_VOP_LOCKED(vp, "unp_connect"); 1152 vfslocked = NDHASGIANT(&nd); 1153 NDFREE(&nd, NDF_ONLY_PNBUF); 1154 if (error) 1155 goto bad; 1156 1157 if (vp->v_type != VSOCK) { 1158 error = ENOTSOCK; 1159 goto bad; 1160 } 1161 #ifdef MAC 1162 error = mac_check_vnode_open(td->td_ucred, vp, VWRITE | VREAD); 1163 if (error) 1164 goto bad; 1165 #endif 1166 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 1167 if (error) 1168 goto bad; 1169 VFS_UNLOCK_GIANT(vfslocked); 1170 1171 unp = sotounpcb(so); 1172 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1173 1174 /* 1175 * Lock global lock for two reasons: make sure v_socket is stable, 1176 * and to protect simultaneous locking of multiple pcbs. 1177 */ 1178 UNP_GLOBAL_WLOCK(); 1179 so2 = vp->v_socket; 1180 if (so2 == NULL) { 1181 error = ECONNREFUSED; 1182 goto bad2; 1183 } 1184 if (so->so_type != so2->so_type) { 1185 error = EPROTOTYPE; 1186 goto bad2; 1187 } 1188 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1189 if (so2->so_options & SO_ACCEPTCONN) { 1190 /* 1191 * We can't drop the global lock here or 'so2' may 1192 * become invalid. As a result, we need to handle 1193 * possibly lock recursion in uipc_attach. 1194 */ 1195 so3 = sonewconn(so2, 0); 1196 } else 1197 so3 = NULL; 1198 if (so3 == NULL) { 1199 error = ECONNREFUSED; 1200 goto bad2; 1201 } 1202 unp = sotounpcb(so); 1203 unp2 = sotounpcb(so2); 1204 unp3 = sotounpcb(so3); 1205 UNP_PCB_LOCK(unp); 1206 UNP_PCB_LOCK(unp2); 1207 UNP_PCB_LOCK(unp3); 1208 if (unp2->unp_addr != NULL) { 1209 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 1210 unp3->unp_addr = (struct sockaddr_un *) sa; 1211 sa = NULL; 1212 } 1213 /* 1214 * unp_peercred management: 1215 * 1216 * The connecter's (client's) credentials are copied from its 1217 * process structure at the time of connect() (which is now). 1218 */ 1219 cru2x(td->td_ucred, &unp3->unp_peercred); 1220 unp3->unp_flags |= UNP_HAVEPC; 1221 /* 1222 * The receiver's (server's) credentials are copied from the 1223 * unp_peercred member of socket on which the former called 1224 * listen(); uipc_listen() cached that process's credentials 1225 * at that time so we can use them now. 1226 */ 1227 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1228 ("unp_connect: listener without cached peercred")); 1229 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1230 sizeof(unp->unp_peercred)); 1231 unp->unp_flags |= UNP_HAVEPC; 1232 if (unp2->unp_flags & UNP_WANTCRED) 1233 unp3->unp_flags |= UNP_WANTCRED; 1234 UNP_PCB_UNLOCK(unp3); 1235 UNP_PCB_UNLOCK(unp2); 1236 UNP_PCB_UNLOCK(unp); 1237 #ifdef MAC 1238 SOCK_LOCK(so); 1239 mac_set_socket_peer_from_socket(so, so3); 1240 mac_set_socket_peer_from_socket(so3, so); 1241 SOCK_UNLOCK(so); 1242 #endif 1243 1244 so2 = so3; 1245 } 1246 unp = sotounpcb(so); 1247 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1248 unp2 = sotounpcb(so2); 1249 KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL")); 1250 UNP_PCB_LOCK(unp); 1251 UNP_PCB_LOCK(unp2); 1252 error = unp_connect2(so, so2, PRU_CONNECT); 1253 UNP_PCB_UNLOCK(unp2); 1254 UNP_PCB_UNLOCK(unp); 1255 bad2: 1256 UNP_GLOBAL_WUNLOCK(); 1257 if (vfslocked) 1258 /* 1259 * Giant has been previously acquired. This means filesystem 1260 * isn't MPSAFE. Do it once again. 1261 */ 1262 mtx_lock(&Giant); 1263 bad: 1264 if (vp != NULL) 1265 vput(vp); 1266 VFS_UNLOCK_GIANT(vfslocked); 1267 free(sa, M_SONAME); 1268 UNP_GLOBAL_WLOCK(); 1269 UNP_PCB_LOCK(unp); 1270 unp->unp_flags &= ~UNP_CONNECTING; 1271 UNP_PCB_UNLOCK(unp); 1272 return (error); 1273 } 1274 1275 static int 1276 unp_connect2(struct socket *so, struct socket *so2, int req) 1277 { 1278 struct unpcb *unp; 1279 struct unpcb *unp2; 1280 1281 unp = sotounpcb(so); 1282 KASSERT(unp != NULL, ("unp_connect2: unp == NULL")); 1283 unp2 = sotounpcb(so2); 1284 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL")); 1285 1286 UNP_GLOBAL_WLOCK_ASSERT(); 1287 UNP_PCB_LOCK_ASSERT(unp); 1288 UNP_PCB_LOCK_ASSERT(unp2); 1289 1290 if (so2->so_type != so->so_type) 1291 return (EPROTOTYPE); 1292 unp->unp_conn = unp2; 1293 1294 switch (so->so_type) { 1295 case SOCK_DGRAM: 1296 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 1297 soisconnected(so); 1298 break; 1299 1300 case SOCK_STREAM: 1301 unp2->unp_conn = unp; 1302 if (req == PRU_CONNECT && 1303 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1304 soisconnecting(so); 1305 else 1306 soisconnected(so); 1307 soisconnected(so2); 1308 break; 1309 1310 default: 1311 panic("unp_connect2"); 1312 } 1313 return (0); 1314 } 1315 1316 static void 1317 unp_disconnect(struct unpcb *unp, struct unpcb *unp2) 1318 { 1319 struct socket *so; 1320 1321 KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL")); 1322 1323 UNP_GLOBAL_WLOCK_ASSERT(); 1324 UNP_PCB_LOCK_ASSERT(unp); 1325 UNP_PCB_LOCK_ASSERT(unp2); 1326 1327 unp->unp_conn = NULL; 1328 switch (unp->unp_socket->so_type) { 1329 case SOCK_DGRAM: 1330 LIST_REMOVE(unp, unp_reflink); 1331 so = unp->unp_socket; 1332 SOCK_LOCK(so); 1333 so->so_state &= ~SS_ISCONNECTED; 1334 SOCK_UNLOCK(so); 1335 break; 1336 1337 case SOCK_STREAM: 1338 soisdisconnected(unp->unp_socket); 1339 unp2->unp_conn = NULL; 1340 soisdisconnected(unp2->unp_socket); 1341 break; 1342 } 1343 } 1344 1345 /* 1346 * unp_pcblist() walks the global list of struct unpcb's to generate a 1347 * pointer list, bumping the refcount on each unpcb. It then copies them out 1348 * sequentially, validating the generation number on each to see if it has 1349 * been detached. All of this is necessary because copyout() may sleep on 1350 * disk I/O. 1351 */ 1352 static int 1353 unp_pcblist(SYSCTL_HANDLER_ARGS) 1354 { 1355 int error, i, n; 1356 int freeunp; 1357 struct unpcb *unp, **unp_list; 1358 unp_gen_t gencnt; 1359 struct xunpgen *xug; 1360 struct unp_head *head; 1361 struct xunpcb *xu; 1362 1363 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1364 1365 /* 1366 * The process of preparing the PCB list is too time-consuming and 1367 * resource-intensive to repeat twice on every request. 1368 */ 1369 if (req->oldptr == NULL) { 1370 n = unp_count; 1371 req->oldidx = 2 * (sizeof *xug) 1372 + (n + n/8) * sizeof(struct xunpcb); 1373 return (0); 1374 } 1375 1376 if (req->newptr != NULL) 1377 return (EPERM); 1378 1379 /* 1380 * OK, now we're committed to doing something. 1381 */ 1382 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1383 UNP_GLOBAL_RLOCK(); 1384 gencnt = unp_gencnt; 1385 n = unp_count; 1386 UNP_GLOBAL_RUNLOCK(); 1387 1388 xug->xug_len = sizeof *xug; 1389 xug->xug_count = n; 1390 xug->xug_gen = gencnt; 1391 xug->xug_sogen = so_gencnt; 1392 error = SYSCTL_OUT(req, xug, sizeof *xug); 1393 if (error) { 1394 free(xug, M_TEMP); 1395 return (error); 1396 } 1397 1398 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1399 1400 UNP_GLOBAL_RLOCK(); 1401 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1402 unp = LIST_NEXT(unp, unp_link)) { 1403 UNP_PCB_LOCK(unp); 1404 if (unp->unp_gencnt <= gencnt) { 1405 if (cr_cansee(req->td->td_ucred, 1406 unp->unp_socket->so_cred)) { 1407 UNP_PCB_UNLOCK(unp); 1408 continue; 1409 } 1410 unp_list[i++] = unp; 1411 unp->unp_refcount++; 1412 } 1413 UNP_PCB_UNLOCK(unp); 1414 } 1415 UNP_GLOBAL_RUNLOCK(); 1416 n = i; /* In case we lost some during malloc. */ 1417 1418 error = 0; 1419 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 1420 for (i = 0; i < n; i++) { 1421 unp = unp_list[i]; 1422 UNP_PCB_LOCK(unp); 1423 unp->unp_refcount--; 1424 if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) { 1425 xu->xu_len = sizeof *xu; 1426 xu->xu_unpp = unp; 1427 /* 1428 * XXX - need more locking here to protect against 1429 * connect/disconnect races for SMP. 1430 */ 1431 if (unp->unp_addr != NULL) 1432 bcopy(unp->unp_addr, &xu->xu_addr, 1433 unp->unp_addr->sun_len); 1434 if (unp->unp_conn != NULL && 1435 unp->unp_conn->unp_addr != NULL) 1436 bcopy(unp->unp_conn->unp_addr, 1437 &xu->xu_caddr, 1438 unp->unp_conn->unp_addr->sun_len); 1439 bcopy(unp, &xu->xu_unp, sizeof *unp); 1440 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1441 UNP_PCB_UNLOCK(unp); 1442 error = SYSCTL_OUT(req, xu, sizeof *xu); 1443 } else { 1444 freeunp = (unp->unp_refcount == 0); 1445 UNP_PCB_UNLOCK(unp); 1446 if (freeunp) { 1447 UNP_PCB_LOCK_DESTROY(unp); 1448 uma_zfree(unp_zone, unp); 1449 } 1450 } 1451 } 1452 free(xu, M_TEMP); 1453 if (!error) { 1454 /* 1455 * Give the user an updated idea of our state. If the 1456 * generation differs from what we told her before, she knows 1457 * that something happened while we were processing this 1458 * request, and it might be necessary to retry. 1459 */ 1460 xug->xug_gen = unp_gencnt; 1461 xug->xug_sogen = so_gencnt; 1462 xug->xug_count = unp_count; 1463 error = SYSCTL_OUT(req, xug, sizeof *xug); 1464 } 1465 free(unp_list, M_TEMP); 1466 free(xug, M_TEMP); 1467 return (error); 1468 } 1469 1470 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1471 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1472 "List of active local datagram sockets"); 1473 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1474 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1475 "List of active local stream sockets"); 1476 1477 static void 1478 unp_shutdown(struct unpcb *unp) 1479 { 1480 struct unpcb *unp2; 1481 struct socket *so; 1482 1483 UNP_GLOBAL_WLOCK_ASSERT(); 1484 UNP_PCB_LOCK_ASSERT(unp); 1485 1486 unp2 = unp->unp_conn; 1487 if (unp->unp_socket->so_type == SOCK_STREAM && unp2 != NULL) { 1488 so = unp2->unp_socket; 1489 if (so != NULL) 1490 socantrcvmore(so); 1491 } 1492 } 1493 1494 static void 1495 unp_drop(struct unpcb *unp, int errno) 1496 { 1497 struct socket *so = unp->unp_socket; 1498 struct unpcb *unp2; 1499 1500 UNP_GLOBAL_WLOCK_ASSERT(); 1501 UNP_PCB_LOCK_ASSERT(unp); 1502 1503 so->so_error = errno; 1504 unp2 = unp->unp_conn; 1505 if (unp2 == NULL) 1506 return; 1507 1508 UNP_PCB_LOCK(unp2); 1509 unp_disconnect(unp, unp2); 1510 UNP_PCB_UNLOCK(unp2); 1511 } 1512 1513 static void 1514 unp_freerights(struct file **rp, int fdcount) 1515 { 1516 int i; 1517 struct file *fp; 1518 1519 for (i = 0; i < fdcount; i++) { 1520 /* 1521 * Zero the pointer before calling unp_discard since it may 1522 * end up in unp_gc().. 1523 * 1524 * XXXRW: This is less true than it used to be. 1525 */ 1526 fp = *rp; 1527 *rp++ = NULL; 1528 unp_discard(fp); 1529 } 1530 } 1531 1532 int 1533 unp_externalize(struct mbuf *control, struct mbuf **controlp) 1534 { 1535 struct thread *td = curthread; /* XXX */ 1536 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1537 int i; 1538 int *fdp; 1539 struct file **rp; 1540 struct file *fp; 1541 void *data; 1542 socklen_t clen = control->m_len, datalen; 1543 int error, newfds; 1544 int f; 1545 u_int newlen; 1546 1547 UNP_GLOBAL_UNLOCK_ASSERT(); 1548 1549 error = 0; 1550 if (controlp != NULL) /* controlp == NULL => free control messages */ 1551 *controlp = NULL; 1552 1553 while (cm != NULL) { 1554 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1555 error = EINVAL; 1556 break; 1557 } 1558 1559 data = CMSG_DATA(cm); 1560 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1561 1562 if (cm->cmsg_level == SOL_SOCKET 1563 && cm->cmsg_type == SCM_RIGHTS) { 1564 newfds = datalen / sizeof(struct file *); 1565 rp = data; 1566 1567 /* If we're not outputting the descriptors free them. */ 1568 if (error || controlp == NULL) { 1569 unp_freerights(rp, newfds); 1570 goto next; 1571 } 1572 FILEDESC_XLOCK(td->td_proc->p_fd); 1573 /* if the new FD's will not fit free them. */ 1574 if (!fdavail(td, newfds)) { 1575 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1576 error = EMSGSIZE; 1577 unp_freerights(rp, newfds); 1578 goto next; 1579 } 1580 /* 1581 * Now change each pointer to an fd in the global 1582 * table to an integer that is the index to the local 1583 * fd table entry that we set up to point to the 1584 * global one we are transferring. 1585 */ 1586 newlen = newfds * sizeof(int); 1587 *controlp = sbcreatecontrol(NULL, newlen, 1588 SCM_RIGHTS, SOL_SOCKET); 1589 if (*controlp == NULL) { 1590 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1591 error = E2BIG; 1592 unp_freerights(rp, newfds); 1593 goto next; 1594 } 1595 1596 fdp = (int *) 1597 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1598 for (i = 0; i < newfds; i++) { 1599 if (fdalloc(td, 0, &f)) 1600 panic("unp_externalize fdalloc failed"); 1601 fp = *rp++; 1602 td->td_proc->p_fd->fd_ofiles[f] = fp; 1603 FILE_LOCK(fp); 1604 fp->f_msgcount--; 1605 FILE_UNLOCK(fp); 1606 unp_rights--; 1607 *fdp++ = f; 1608 } 1609 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1610 } else { 1611 /* We can just copy anything else across. */ 1612 if (error || controlp == NULL) 1613 goto next; 1614 *controlp = sbcreatecontrol(NULL, datalen, 1615 cm->cmsg_type, cm->cmsg_level); 1616 if (*controlp == NULL) { 1617 error = ENOBUFS; 1618 goto next; 1619 } 1620 bcopy(data, 1621 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1622 datalen); 1623 } 1624 1625 controlp = &(*controlp)->m_next; 1626 1627 next: 1628 if (CMSG_SPACE(datalen) < clen) { 1629 clen -= CMSG_SPACE(datalen); 1630 cm = (struct cmsghdr *) 1631 ((caddr_t)cm + CMSG_SPACE(datalen)); 1632 } else { 1633 clen = 0; 1634 cm = NULL; 1635 } 1636 } 1637 1638 m_freem(control); 1639 1640 return (error); 1641 } 1642 1643 static void 1644 unp_zone_change(void *tag) 1645 { 1646 1647 uma_zone_set_max(unp_zone, maxsockets); 1648 } 1649 1650 void 1651 unp_init(void) 1652 { 1653 1654 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1655 NULL, NULL, UMA_ALIGN_PTR, 0); 1656 if (unp_zone == NULL) 1657 panic("unp_init"); 1658 uma_zone_set_max(unp_zone, maxsockets); 1659 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change, 1660 NULL, EVENTHANDLER_PRI_ANY); 1661 LIST_INIT(&unp_dhead); 1662 LIST_INIT(&unp_shead); 1663 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1664 UNP_GLOBAL_LOCK_INIT(); 1665 } 1666 1667 static int 1668 unp_internalize(struct mbuf **controlp, struct thread *td) 1669 { 1670 struct mbuf *control = *controlp; 1671 struct proc *p = td->td_proc; 1672 struct filedesc *fdescp = p->p_fd; 1673 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1674 struct cmsgcred *cmcred; 1675 struct file **rp; 1676 struct file *fp; 1677 struct timeval *tv; 1678 int i, fd, *fdp; 1679 void *data; 1680 socklen_t clen = control->m_len, datalen; 1681 int error, oldfds; 1682 u_int newlen; 1683 1684 UNP_GLOBAL_UNLOCK_ASSERT(); 1685 1686 error = 0; 1687 *controlp = NULL; 1688 1689 while (cm != NULL) { 1690 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1691 || cm->cmsg_len > clen) { 1692 error = EINVAL; 1693 goto out; 1694 } 1695 1696 data = CMSG_DATA(cm); 1697 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1698 1699 switch (cm->cmsg_type) { 1700 /* 1701 * Fill in credential information. 1702 */ 1703 case SCM_CREDS: 1704 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1705 SCM_CREDS, SOL_SOCKET); 1706 if (*controlp == NULL) { 1707 error = ENOBUFS; 1708 goto out; 1709 } 1710 1711 cmcred = (struct cmsgcred *) 1712 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1713 cmcred->cmcred_pid = p->p_pid; 1714 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1715 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1716 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1717 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1718 CMGROUP_MAX); 1719 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1720 cmcred->cmcred_groups[i] = 1721 td->td_ucred->cr_groups[i]; 1722 break; 1723 1724 case SCM_RIGHTS: 1725 oldfds = datalen / sizeof (int); 1726 /* 1727 * Check that all the FDs passed in refer to legal 1728 * files. If not, reject the entire operation. 1729 */ 1730 fdp = data; 1731 FILEDESC_SLOCK(fdescp); 1732 for (i = 0; i < oldfds; i++) { 1733 fd = *fdp++; 1734 if ((unsigned)fd >= fdescp->fd_nfiles || 1735 fdescp->fd_ofiles[fd] == NULL) { 1736 FILEDESC_SUNLOCK(fdescp); 1737 error = EBADF; 1738 goto out; 1739 } 1740 fp = fdescp->fd_ofiles[fd]; 1741 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1742 FILEDESC_SUNLOCK(fdescp); 1743 error = EOPNOTSUPP; 1744 goto out; 1745 } 1746 1747 } 1748 1749 /* 1750 * Now replace the integer FDs with pointers to 1751 * the associated global file table entry.. 1752 */ 1753 newlen = oldfds * sizeof(struct file *); 1754 *controlp = sbcreatecontrol(NULL, newlen, 1755 SCM_RIGHTS, SOL_SOCKET); 1756 if (*controlp == NULL) { 1757 FILEDESC_SUNLOCK(fdescp); 1758 error = E2BIG; 1759 goto out; 1760 } 1761 1762 fdp = data; 1763 rp = (struct file **) 1764 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1765 for (i = 0; i < oldfds; i++) { 1766 fp = fdescp->fd_ofiles[*fdp++]; 1767 *rp++ = fp; 1768 FILE_LOCK(fp); 1769 fp->f_count++; 1770 fp->f_msgcount++; 1771 FILE_UNLOCK(fp); 1772 unp_rights++; 1773 } 1774 FILEDESC_SUNLOCK(fdescp); 1775 break; 1776 1777 case SCM_TIMESTAMP: 1778 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1779 SCM_TIMESTAMP, SOL_SOCKET); 1780 if (*controlp == NULL) { 1781 error = ENOBUFS; 1782 goto out; 1783 } 1784 tv = (struct timeval *) 1785 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1786 microtime(tv); 1787 break; 1788 1789 default: 1790 error = EINVAL; 1791 goto out; 1792 } 1793 1794 controlp = &(*controlp)->m_next; 1795 1796 if (CMSG_SPACE(datalen) < clen) { 1797 clen -= CMSG_SPACE(datalen); 1798 cm = (struct cmsghdr *) 1799 ((caddr_t)cm + CMSG_SPACE(datalen)); 1800 } else { 1801 clen = 0; 1802 cm = NULL; 1803 } 1804 } 1805 1806 out: 1807 m_freem(control); 1808 1809 return (error); 1810 } 1811 1812 static struct mbuf * 1813 unp_addsockcred(struct thread *td, struct mbuf *control) 1814 { 1815 struct mbuf *m, *n, *n_prev; 1816 struct sockcred *sc; 1817 const struct cmsghdr *cm; 1818 int ngroups; 1819 int i; 1820 1821 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); 1822 1823 m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET); 1824 if (m == NULL) 1825 return (control); 1826 1827 sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *)); 1828 sc->sc_uid = td->td_ucred->cr_ruid; 1829 sc->sc_euid = td->td_ucred->cr_uid; 1830 sc->sc_gid = td->td_ucred->cr_rgid; 1831 sc->sc_egid = td->td_ucred->cr_gid; 1832 sc->sc_ngroups = ngroups; 1833 for (i = 0; i < sc->sc_ngroups; i++) 1834 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 1835 1836 /* 1837 * Unlink SCM_CREDS control messages (struct cmsgcred), since just 1838 * created SCM_CREDS control message (struct sockcred) has another 1839 * format. 1840 */ 1841 if (control != NULL) 1842 for (n = control, n_prev = NULL; n != NULL;) { 1843 cm = mtod(n, struct cmsghdr *); 1844 if (cm->cmsg_level == SOL_SOCKET && 1845 cm->cmsg_type == SCM_CREDS) { 1846 if (n_prev == NULL) 1847 control = n->m_next; 1848 else 1849 n_prev->m_next = n->m_next; 1850 n = m_free(n); 1851 } else { 1852 n_prev = n; 1853 n = n->m_next; 1854 } 1855 } 1856 1857 /* Prepend it to the head. */ 1858 m->m_next = control; 1859 1860 return (m); 1861 } 1862 1863 /* 1864 * unp_defer indicates whether additional work has been defered for a future 1865 * pass through unp_gc(). It is thread local and does not require explicit 1866 * synchronization. 1867 */ 1868 static int unp_defer; 1869 1870 static int unp_taskcount; 1871 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, ""); 1872 1873 static int unp_recycled; 1874 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, ""); 1875 1876 static void 1877 unp_gc(__unused void *arg, int pending) 1878 { 1879 struct file *fp, *nextfp; 1880 struct socket *so; 1881 struct file **extra_ref, **fpp; 1882 int nunref, i; 1883 int nfiles_snap; 1884 int nfiles_slack = 20; 1885 1886 unp_taskcount++; 1887 unp_defer = 0; 1888 /* 1889 * Before going through all this, set all FDs to be NOT deferred and 1890 * NOT externally accessible. 1891 */ 1892 sx_slock(&filelist_lock); 1893 LIST_FOREACH(fp, &filehead, f_list) 1894 fp->f_gcflag &= ~(FMARK|FDEFER); 1895 do { 1896 KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer)); 1897 LIST_FOREACH(fp, &filehead, f_list) { 1898 FILE_LOCK(fp); 1899 /* 1900 * If the file is not open, skip it -- could be a 1901 * file in the process of being opened, or in the 1902 * process of being closed. If the file is 1903 * "closing", it may have been marked for deferred 1904 * consideration. Clear the flag now if so. 1905 */ 1906 if (fp->f_count == 0) { 1907 if (fp->f_gcflag & FDEFER) 1908 unp_defer--; 1909 fp->f_gcflag &= ~(FMARK|FDEFER); 1910 FILE_UNLOCK(fp); 1911 continue; 1912 } 1913 /* 1914 * If we already marked it as 'defer' in a 1915 * previous pass, then try to process it this 1916 * time and un-mark it. 1917 */ 1918 if (fp->f_gcflag & FDEFER) { 1919 fp->f_gcflag &= ~FDEFER; 1920 unp_defer--; 1921 } else { 1922 /* 1923 * If it's not deferred, then check if it's 1924 * already marked.. if so skip it 1925 */ 1926 if (fp->f_gcflag & FMARK) { 1927 FILE_UNLOCK(fp); 1928 continue; 1929 } 1930 /* 1931 * If all references are from messages in 1932 * transit, then skip it. it's not externally 1933 * accessible. 1934 */ 1935 if (fp->f_count == fp->f_msgcount) { 1936 FILE_UNLOCK(fp); 1937 continue; 1938 } 1939 /* 1940 * If it got this far then it must be 1941 * externally accessible. 1942 */ 1943 fp->f_gcflag |= FMARK; 1944 } 1945 /* 1946 * Either it was deferred, or it is externally 1947 * accessible and not already marked so. Now check 1948 * if it is possibly one of OUR sockets. 1949 */ 1950 if (fp->f_type != DTYPE_SOCKET || 1951 (so = fp->f_data) == NULL) { 1952 FILE_UNLOCK(fp); 1953 continue; 1954 } 1955 if (so->so_proto->pr_domain != &localdomain || 1956 (so->so_proto->pr_flags & PR_RIGHTS) == 0) { 1957 FILE_UNLOCK(fp); 1958 continue; 1959 } 1960 1961 /* 1962 * Tell any other threads that do a subsequent 1963 * fdrop() that we are scanning the message 1964 * buffers. 1965 */ 1966 fp->f_gcflag |= FWAIT; 1967 FILE_UNLOCK(fp); 1968 1969 /* 1970 * So, Ok, it's one of our sockets and it IS 1971 * externally accessible (or was deferred). Now we 1972 * look to see if we hold any file descriptors in its 1973 * message buffers. Follow those links and mark them 1974 * as accessible too. 1975 */ 1976 SOCKBUF_LOCK(&so->so_rcv); 1977 unp_scan(so->so_rcv.sb_mb, unp_mark); 1978 SOCKBUF_UNLOCK(&so->so_rcv); 1979 1980 /* 1981 * Wake up any threads waiting in fdrop(). 1982 */ 1983 FILE_LOCK(fp); 1984 fp->f_gcflag &= ~FWAIT; 1985 wakeup(&fp->f_gcflag); 1986 FILE_UNLOCK(fp); 1987 } 1988 } while (unp_defer); 1989 sx_sunlock(&filelist_lock); 1990 /* 1991 * XXXRW: The following comments need updating for a post-SMPng and 1992 * deferred unp_gc() world, but are still generally accurate. 1993 * 1994 * We grab an extra reference to each of the file table entries that 1995 * are not otherwise accessible and then free the rights that are 1996 * stored in messages on them. 1997 * 1998 * The bug in the orginal code is a little tricky, so I'll describe 1999 * what's wrong with it here. 2000 * 2001 * It is incorrect to simply unp_discard each entry for f_msgcount 2002 * times -- consider the case of sockets A and B that contain 2003 * references to each other. On a last close of some other socket, 2004 * we trigger a gc since the number of outstanding rights (unp_rights) 2005 * is non-zero. If during the sweep phase the gc code unp_discards, 2006 * we end up doing a (full) closef on the descriptor. A closef on A 2007 * results in the following chain. Closef calls soo_close, which 2008 * calls soclose. Soclose calls first (through the switch 2009 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2010 * returns because the previous instance had set unp_gcing, and we 2011 * return all the way back to soclose, which marks the socket with 2012 * SS_NOFDREF, and then calls sofree. Sofree calls sorflush to free 2013 * up the rights that are queued in messages on the socket A, i.e., 2014 * the reference on B. The sorflush calls via the dom_dispose switch 2015 * unp_dispose, which unp_scans with unp_discard. This second 2016 * instance of unp_discard just calls closef on B. 2017 * 2018 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2019 * which results in another closef on A. Unfortunately, A is already 2020 * being closed, and the descriptor has already been marked with 2021 * SS_NOFDREF, and soclose panics at this point. 2022 * 2023 * Here, we first take an extra reference to each inaccessible 2024 * descriptor. Then, we call sorflush ourself, since we know it is a 2025 * Unix domain socket anyhow. After we destroy all the rights 2026 * carried in messages, we do a last closef to get rid of our extra 2027 * reference. This is the last close, and the unp_detach etc will 2028 * shut down the socket. 2029 * 2030 * 91/09/19, bsy@cs.cmu.edu 2031 */ 2032 again: 2033 nfiles_snap = openfiles + nfiles_slack; /* some slack */ 2034 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 2035 M_WAITOK); 2036 sx_slock(&filelist_lock); 2037 if (nfiles_snap < openfiles) { 2038 sx_sunlock(&filelist_lock); 2039 free(extra_ref, M_TEMP); 2040 nfiles_slack += 20; 2041 goto again; 2042 } 2043 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 2044 fp != NULL; fp = nextfp) { 2045 nextfp = LIST_NEXT(fp, f_list); 2046 FILE_LOCK(fp); 2047 /* 2048 * If it's not open, skip it 2049 */ 2050 if (fp->f_count == 0) { 2051 FILE_UNLOCK(fp); 2052 continue; 2053 } 2054 /* 2055 * If all refs are from msgs, and it's not marked accessible 2056 * then it must be referenced from some unreachable cycle of 2057 * (shut-down) FDs, so include it in our list of FDs to 2058 * remove. 2059 */ 2060 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 2061 *fpp++ = fp; 2062 nunref++; 2063 fp->f_count++; 2064 } 2065 FILE_UNLOCK(fp); 2066 } 2067 sx_sunlock(&filelist_lock); 2068 /* 2069 * For each FD on our hit list, do the following two things: 2070 */ 2071 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2072 struct file *tfp = *fpp; 2073 FILE_LOCK(tfp); 2074 if (tfp->f_type == DTYPE_SOCKET && 2075 tfp->f_data != NULL) { 2076 FILE_UNLOCK(tfp); 2077 sorflush(tfp->f_data); 2078 } else { 2079 FILE_UNLOCK(tfp); 2080 } 2081 } 2082 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2083 closef(*fpp, (struct thread *) NULL); 2084 unp_recycled++; 2085 } 2086 free(extra_ref, M_TEMP); 2087 } 2088 2089 void 2090 unp_dispose(struct mbuf *m) 2091 { 2092 2093 if (m) 2094 unp_scan(m, unp_discard); 2095 } 2096 2097 static void 2098 unp_scan(struct mbuf *m0, void (*op)(struct file *)) 2099 { 2100 struct mbuf *m; 2101 struct file **rp; 2102 struct cmsghdr *cm; 2103 void *data; 2104 int i; 2105 socklen_t clen, datalen; 2106 int qfds; 2107 2108 while (m0 != NULL) { 2109 for (m = m0; m; m = m->m_next) { 2110 if (m->m_type != MT_CONTROL) 2111 continue; 2112 2113 cm = mtod(m, struct cmsghdr *); 2114 clen = m->m_len; 2115 2116 while (cm != NULL) { 2117 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 2118 break; 2119 2120 data = CMSG_DATA(cm); 2121 datalen = (caddr_t)cm + cm->cmsg_len 2122 - (caddr_t)data; 2123 2124 if (cm->cmsg_level == SOL_SOCKET && 2125 cm->cmsg_type == SCM_RIGHTS) { 2126 qfds = datalen / sizeof (struct file *); 2127 rp = data; 2128 for (i = 0; i < qfds; i++) 2129 (*op)(*rp++); 2130 } 2131 2132 if (CMSG_SPACE(datalen) < clen) { 2133 clen -= CMSG_SPACE(datalen); 2134 cm = (struct cmsghdr *) 2135 ((caddr_t)cm + CMSG_SPACE(datalen)); 2136 } else { 2137 clen = 0; 2138 cm = NULL; 2139 } 2140 } 2141 } 2142 m0 = m0->m_act; 2143 } 2144 } 2145 2146 static void 2147 unp_mark(struct file *fp) 2148 { 2149 2150 /* XXXRW: Should probably assert file list lock here. */ 2151 2152 if (fp->f_gcflag & FMARK) 2153 return; 2154 unp_defer++; 2155 fp->f_gcflag |= (FMARK|FDEFER); 2156 } 2157 2158 static void 2159 unp_discard(struct file *fp) 2160 { 2161 2162 UNP_GLOBAL_WLOCK(); 2163 FILE_LOCK(fp); 2164 fp->f_msgcount--; 2165 unp_rights--; 2166 FILE_UNLOCK(fp); 2167 UNP_GLOBAL_WUNLOCK(); 2168 (void) closef(fp, (struct thread *)NULL); 2169 } 2170 2171 #ifdef DDB 2172 static void 2173 db_print_indent(int indent) 2174 { 2175 int i; 2176 2177 for (i = 0; i < indent; i++) 2178 db_printf(" "); 2179 } 2180 2181 static void 2182 db_print_unpflags(int unp_flags) 2183 { 2184 int comma; 2185 2186 comma = 0; 2187 if (unp_flags & UNP_HAVEPC) { 2188 db_printf("%sUNP_HAVEPC", comma ? ", " : ""); 2189 comma = 1; 2190 } 2191 if (unp_flags & UNP_HAVEPCCACHED) { 2192 db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : ""); 2193 comma = 1; 2194 } 2195 if (unp_flags & UNP_WANTCRED) { 2196 db_printf("%sUNP_WANTCRED", comma ? ", " : ""); 2197 comma = 1; 2198 } 2199 if (unp_flags & UNP_CONNWAIT) { 2200 db_printf("%sUNP_CONNWAIT", comma ? ", " : ""); 2201 comma = 1; 2202 } 2203 if (unp_flags & UNP_CONNECTING) { 2204 db_printf("%sUNP_CONNECTING", comma ? ", " : ""); 2205 comma = 1; 2206 } 2207 if (unp_flags & UNP_BINDING) { 2208 db_printf("%sUNP_BINDING", comma ? ", " : ""); 2209 comma = 1; 2210 } 2211 } 2212 2213 static void 2214 db_print_xucred(int indent, struct xucred *xu) 2215 { 2216 int comma, i; 2217 2218 db_print_indent(indent); 2219 db_printf("cr_version: %u cr_uid: %u cr_ngroups: %d\n", 2220 xu->cr_version, xu->cr_uid, xu->cr_ngroups); 2221 db_print_indent(indent); 2222 db_printf("cr_groups: "); 2223 comma = 0; 2224 for (i = 0; i < xu->cr_ngroups; i++) { 2225 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]); 2226 comma = 1; 2227 } 2228 db_printf("\n"); 2229 } 2230 2231 static void 2232 db_print_unprefs(int indent, struct unp_head *uh) 2233 { 2234 struct unpcb *unp; 2235 int counter; 2236 2237 counter = 0; 2238 LIST_FOREACH(unp, uh, unp_reflink) { 2239 if (counter % 4 == 0) 2240 db_print_indent(indent); 2241 db_printf("%p ", unp); 2242 if (counter % 4 == 3) 2243 db_printf("\n"); 2244 counter++; 2245 } 2246 if (counter != 0 && counter % 4 != 0) 2247 db_printf("\n"); 2248 } 2249 2250 DB_SHOW_COMMAND(unpcb, db_show_unpcb) 2251 { 2252 struct unpcb *unp; 2253 2254 if (!have_addr) { 2255 db_printf("usage: show unpcb <addr>\n"); 2256 return; 2257 } 2258 unp = (struct unpcb *)addr; 2259 2260 db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket, 2261 unp->unp_vnode); 2262 2263 db_printf("unp_ino: %d unp_conn: %p\n", unp->unp_ino, 2264 unp->unp_conn); 2265 2266 db_printf("unp_refs:\n"); 2267 db_print_unprefs(2, &unp->unp_refs); 2268 2269 /* XXXRW: Would be nice to print the full address, if any. */ 2270 db_printf("unp_addr: %p\n", unp->unp_addr); 2271 2272 db_printf("unp_cc: %d unp_mbcnt: %d unp_gencnt: %llu\n", 2273 unp->unp_cc, unp->unp_mbcnt, 2274 (unsigned long long)unp->unp_gencnt); 2275 2276 db_printf("unp_flags: %x (", unp->unp_flags); 2277 db_print_unpflags(unp->unp_flags); 2278 db_printf(")\n"); 2279 2280 db_printf("unp_peercred:\n"); 2281 db_print_xucred(2, &unp->unp_peercred); 2282 2283 db_printf("unp_refcount: %u\n", unp->unp_refcount); 2284 } 2285 #endif
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