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