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_dgram, uipc_usrreqs_stream; 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_stream 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_dgram 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 if (soun->sun_len > sizeof(struct sockaddr_un)) 399 return (EINVAL); 400 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 401 if (namelen <= 0) 402 return (EINVAL); 403 404 /* 405 * We don't allow simultaneous bind() calls on a single UNIX domain 406 * socket, so flag in-progress operations, and return an error if an 407 * operation is already in progress. 408 * 409 * Historically, we have not allowed a socket to be rebound, so this 410 * also returns an error. Not allowing re-binding simplifies the 411 * implementation and avoids a great many possible failure modes. 412 */ 413 UNP_PCB_LOCK(unp); 414 if (unp->unp_vnode != NULL) { 415 UNP_PCB_UNLOCK(unp); 416 return (EINVAL); 417 } 418 if (unp->unp_flags & UNP_BINDING) { 419 UNP_PCB_UNLOCK(unp); 420 return (EALREADY); 421 } 422 unp->unp_flags |= UNP_BINDING; 423 UNP_PCB_UNLOCK(unp); 424 425 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 426 bcopy(soun->sun_path, buf, namelen); 427 buf[namelen] = 0; 428 429 restart: 430 vfslocked = 0; 431 NDINIT(&nd, CREATE, MPSAFE | NOFOLLOW | LOCKPARENT | SAVENAME, 432 UIO_SYSSPACE, buf, td); 433 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 434 error = namei(&nd); 435 if (error) 436 goto error; 437 vp = nd.ni_vp; 438 vfslocked = NDHASGIANT(&nd); 439 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 440 NDFREE(&nd, NDF_ONLY_PNBUF); 441 if (nd.ni_dvp == vp) 442 vrele(nd.ni_dvp); 443 else 444 vput(nd.ni_dvp); 445 if (vp != NULL) { 446 vrele(vp); 447 error = EADDRINUSE; 448 goto error; 449 } 450 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 451 if (error) 452 goto error; 453 VFS_UNLOCK_GIANT(vfslocked); 454 goto restart; 455 } 456 VATTR_NULL(&vattr); 457 vattr.va_type = VSOCK; 458 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 459 #ifdef MAC 460 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 461 &vattr); 462 #endif 463 if (error == 0) { 464 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 465 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 466 } 467 NDFREE(&nd, NDF_ONLY_PNBUF); 468 vput(nd.ni_dvp); 469 if (error) { 470 vn_finished_write(mp); 471 goto error; 472 } 473 vp = nd.ni_vp; 474 ASSERT_VOP_ELOCKED(vp, "uipc_bind"); 475 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 476 477 UNP_GLOBAL_WLOCK(); 478 UNP_PCB_LOCK(unp); 479 vp->v_socket = unp->unp_socket; 480 unp->unp_vnode = vp; 481 unp->unp_addr = soun; 482 unp->unp_flags &= ~UNP_BINDING; 483 UNP_PCB_UNLOCK(unp); 484 UNP_GLOBAL_WUNLOCK(); 485 VOP_UNLOCK(vp, 0, td); 486 vn_finished_write(mp); 487 VFS_UNLOCK_GIANT(vfslocked); 488 free(buf, M_TEMP); 489 return (0); 490 491 error: 492 VFS_UNLOCK_GIANT(vfslocked); 493 UNP_PCB_LOCK(unp); 494 unp->unp_flags &= ~UNP_BINDING; 495 UNP_PCB_UNLOCK(unp); 496 free(buf, M_TEMP); 497 return (error); 498 } 499 500 static int 501 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 502 { 503 int error; 504 505 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 506 UNP_GLOBAL_WLOCK(); 507 error = unp_connect(so, nam, td); 508 UNP_GLOBAL_WUNLOCK(); 509 return (error); 510 } 511 512 static void 513 uipc_close(struct socket *so) 514 { 515 struct unpcb *unp, *unp2; 516 517 unp = sotounpcb(so); 518 KASSERT(unp != NULL, ("uipc_close: unp == NULL")); 519 520 UNP_GLOBAL_WLOCK(); 521 UNP_PCB_LOCK(unp); 522 unp2 = unp->unp_conn; 523 if (unp2 != NULL) { 524 UNP_PCB_LOCK(unp2); 525 unp_disconnect(unp, unp2); 526 UNP_PCB_UNLOCK(unp2); 527 } 528 UNP_PCB_UNLOCK(unp); 529 UNP_GLOBAL_WUNLOCK(); 530 } 531 532 static int 533 uipc_connect2(struct socket *so1, struct socket *so2) 534 { 535 struct unpcb *unp, *unp2; 536 int error; 537 538 UNP_GLOBAL_WLOCK(); 539 unp = so1->so_pcb; 540 KASSERT(unp != NULL, ("uipc_connect2: unp == NULL")); 541 UNP_PCB_LOCK(unp); 542 unp2 = so2->so_pcb; 543 KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL")); 544 UNP_PCB_LOCK(unp2); 545 error = unp_connect2(so1, so2, PRU_CONNECT2); 546 UNP_PCB_UNLOCK(unp2); 547 UNP_PCB_UNLOCK(unp); 548 UNP_GLOBAL_WUNLOCK(); 549 return (error); 550 } 551 552 static void 553 uipc_detach(struct socket *so) 554 { 555 struct unpcb *unp, *unp2; 556 struct sockaddr_un *saved_unp_addr; 557 struct vnode *vp; 558 int freeunp, local_unp_rights; 559 560 unp = sotounpcb(so); 561 KASSERT(unp != NULL, ("uipc_detach: unp == NULL")); 562 563 UNP_GLOBAL_WLOCK(); 564 UNP_PCB_LOCK(unp); 565 566 LIST_REMOVE(unp, unp_link); 567 unp->unp_gencnt = ++unp_gencnt; 568 --unp_count; 569 570 /* 571 * XXXRW: Should assert vp->v_socket == so. 572 */ 573 if ((vp = unp->unp_vnode) != NULL) { 574 unp->unp_vnode->v_socket = NULL; 575 unp->unp_vnode = NULL; 576 } 577 unp2 = unp->unp_conn; 578 if (unp2 != NULL) { 579 UNP_PCB_LOCK(unp2); 580 unp_disconnect(unp, unp2); 581 UNP_PCB_UNLOCK(unp2); 582 } 583 584 /* 585 * We hold the global lock exclusively, so it's OK to acquire 586 * multiple pcb locks at a time. 587 */ 588 while (!LIST_EMPTY(&unp->unp_refs)) { 589 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 590 591 UNP_PCB_LOCK(ref); 592 unp_drop(ref, ECONNRESET); 593 UNP_PCB_UNLOCK(ref); 594 } 595 local_unp_rights = unp_rights; 596 UNP_GLOBAL_WUNLOCK(); 597 unp->unp_socket->so_pcb = NULL; 598 saved_unp_addr = unp->unp_addr; 599 unp->unp_addr = NULL; 600 unp->unp_refcount--; 601 freeunp = (unp->unp_refcount == 0); 602 if (saved_unp_addr != NULL) 603 FREE(saved_unp_addr, M_SONAME); 604 if (freeunp) { 605 UNP_PCB_LOCK_DESTROY(unp); 606 uma_zfree(unp_zone, unp); 607 } else 608 UNP_PCB_UNLOCK(unp); 609 if (vp) { 610 int vfslocked; 611 612 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 613 vrele(vp); 614 VFS_UNLOCK_GIANT(vfslocked); 615 } 616 if (local_unp_rights) 617 taskqueue_enqueue(taskqueue_thread, &unp_gc_task); 618 } 619 620 static int 621 uipc_disconnect(struct socket *so) 622 { 623 struct unpcb *unp, *unp2; 624 625 unp = sotounpcb(so); 626 KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL")); 627 628 UNP_GLOBAL_WLOCK(); 629 UNP_PCB_LOCK(unp); 630 unp2 = unp->unp_conn; 631 if (unp2 != NULL) { 632 UNP_PCB_LOCK(unp2); 633 unp_disconnect(unp, unp2); 634 UNP_PCB_UNLOCK(unp2); 635 } 636 UNP_PCB_UNLOCK(unp); 637 UNP_GLOBAL_WUNLOCK(); 638 return (0); 639 } 640 641 static int 642 uipc_listen(struct socket *so, int backlog, struct thread *td) 643 { 644 struct unpcb *unp; 645 int error; 646 647 unp = sotounpcb(so); 648 KASSERT(unp != NULL, ("uipc_listen: unp == NULL")); 649 650 UNP_PCB_LOCK(unp); 651 if (unp->unp_vnode == NULL) { 652 UNP_PCB_UNLOCK(unp); 653 return (EINVAL); 654 } 655 656 SOCK_LOCK(so); 657 error = solisten_proto_check(so); 658 if (error == 0) { 659 cru2x(td->td_ucred, &unp->unp_peercred); 660 unp->unp_flags |= UNP_HAVEPCCACHED; 661 solisten_proto(so, backlog); 662 } 663 SOCK_UNLOCK(so); 664 UNP_PCB_UNLOCK(unp); 665 return (error); 666 } 667 668 static int 669 uipc_peeraddr(struct socket *so, struct sockaddr **nam) 670 { 671 struct unpcb *unp, *unp2; 672 const struct sockaddr *sa; 673 674 unp = sotounpcb(so); 675 KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL")); 676 677 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 678 UNP_GLOBAL_RLOCK(); 679 /* 680 * XXX: It seems that this test always fails even when connection is 681 * established. So, this else clause is added as workaround to 682 * return PF_LOCAL sockaddr. 683 */ 684 unp2 = unp->unp_conn; 685 if (unp2 != NULL) { 686 UNP_PCB_LOCK(unp2); 687 if (unp2->unp_addr != NULL) 688 sa = (struct sockaddr *) unp2->unp_addr; 689 else 690 sa = &sun_noname; 691 bcopy(sa, *nam, sa->sa_len); 692 UNP_PCB_UNLOCK(unp2); 693 } else { 694 sa = &sun_noname; 695 bcopy(sa, *nam, sa->sa_len); 696 } 697 UNP_GLOBAL_RUNLOCK(); 698 return (0); 699 } 700 701 static int 702 uipc_rcvd(struct socket *so, int flags) 703 { 704 struct unpcb *unp, *unp2; 705 struct socket *so2; 706 u_int mbcnt, sbcc; 707 u_long newhiwat; 708 709 unp = sotounpcb(so); 710 KASSERT(unp != NULL, ("uipc_rcvd: unp == NULL")); 711 712 if (so->so_type == SOCK_DGRAM) 713 panic("uipc_rcvd DGRAM?"); 714 715 if (so->so_type != SOCK_STREAM) 716 panic("uipc_rcvd unknown socktype"); 717 718 /* 719 * Adjust backpressure on sender and wakeup any waiting to write. 720 * 721 * The unp lock is acquired to maintain the validity of the unp_conn 722 * pointer; no lock on unp2 is required as unp2->unp_socket will be 723 * static as long as we don't permit unp2 to disconnect from unp, 724 * which is prevented by the lock on unp. We cache values from 725 * so_rcv to avoid holding the so_rcv lock over the entire 726 * transaction on the remote so_snd. 727 */ 728 SOCKBUF_LOCK(&so->so_rcv); 729 mbcnt = so->so_rcv.sb_mbcnt; 730 sbcc = so->so_rcv.sb_cc; 731 SOCKBUF_UNLOCK(&so->so_rcv); 732 UNP_PCB_LOCK(unp); 733 unp2 = unp->unp_conn; 734 if (unp2 == NULL) { 735 UNP_PCB_UNLOCK(unp); 736 return (0); 737 } 738 so2 = unp2->unp_socket; 739 SOCKBUF_LOCK(&so2->so_snd); 740 so2->so_snd.sb_mbmax += unp->unp_mbcnt - mbcnt; 741 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - sbcc; 742 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, 743 newhiwat, RLIM_INFINITY); 744 sowwakeup_locked(so2); 745 unp->unp_mbcnt = mbcnt; 746 unp->unp_cc = sbcc; 747 UNP_PCB_UNLOCK(unp); 748 return (0); 749 } 750 751 static int 752 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 753 struct mbuf *control, struct thread *td) 754 { 755 struct unpcb *unp, *unp2; 756 struct socket *so2; 757 u_int mbcnt_delta, sbcc; 758 u_long newhiwat; 759 int error = 0; 760 761 unp = sotounpcb(so); 762 KASSERT(unp != NULL, ("uipc_send: unp == NULL")); 763 764 if (flags & PRUS_OOB) { 765 error = EOPNOTSUPP; 766 goto release; 767 } 768 if (control != NULL && (error = unp_internalize(&control, td))) 769 goto release; 770 if ((nam != NULL) || (flags & PRUS_EOF)) 771 UNP_GLOBAL_WLOCK(); 772 else 773 UNP_GLOBAL_RLOCK(); 774 switch (so->so_type) { 775 case SOCK_DGRAM: 776 { 777 const struct sockaddr *from; 778 779 unp2 = unp->unp_conn; 780 if (nam != NULL) { 781 UNP_GLOBAL_WLOCK_ASSERT(); 782 if (unp2 != NULL) { 783 error = EISCONN; 784 break; 785 } 786 error = unp_connect(so, nam, td); 787 if (error) 788 break; 789 unp2 = unp->unp_conn; 790 } 791 792 /* 793 * Because connect() and send() are non-atomic in a sendto() 794 * with a target address, it's possible that the socket will 795 * have disconnected before the send() can run. In that case 796 * return the slightly counter-intuitive but otherwise 797 * correct error that the socket is not connected. 798 */ 799 if (unp2 == NULL) { 800 error = ENOTCONN; 801 break; 802 } 803 /* Lockless read. */ 804 if (unp2->unp_flags & UNP_WANTCRED) 805 control = unp_addsockcred(td, control); 806 UNP_PCB_LOCK(unp); 807 if (unp->unp_addr != NULL) 808 from = (struct sockaddr *)unp->unp_addr; 809 else 810 from = &sun_noname; 811 so2 = unp2->unp_socket; 812 SOCKBUF_LOCK(&so2->so_rcv); 813 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 814 sorwakeup_locked(so2); 815 m = NULL; 816 control = NULL; 817 } else { 818 SOCKBUF_UNLOCK(&so2->so_rcv); 819 error = ENOBUFS; 820 } 821 if (nam != NULL) { 822 UNP_GLOBAL_WLOCK_ASSERT(); 823 UNP_PCB_LOCK(unp2); 824 unp_disconnect(unp, unp2); 825 UNP_PCB_UNLOCK(unp2); 826 } 827 UNP_PCB_UNLOCK(unp); 828 break; 829 } 830 831 case SOCK_STREAM: 832 if ((so->so_state & SS_ISCONNECTED) == 0) { 833 if (nam != NULL) { 834 UNP_GLOBAL_WLOCK_ASSERT(); 835 error = unp_connect(so, nam, td); 836 if (error) 837 break; /* XXX */ 838 } else { 839 error = ENOTCONN; 840 break; 841 } 842 } 843 844 /* Lockless read. */ 845 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 846 error = EPIPE; 847 break; 848 } 849 850 /* 851 * Because connect() and send() are non-atomic in a sendto() 852 * with a target address, it's possible that the socket will 853 * have disconnected before the send() can run. In that case 854 * return the slightly counter-intuitive but otherwise 855 * correct error that the socket is not connected. 856 * 857 * Locking here must be done carefully: the global lock 858 * prevents interconnections between unpcbs from changing, so 859 * we can traverse from unp to unp2 without acquiring unp's 860 * lock. Socket buffer locks follow unpcb locks, so we can 861 * acquire both remote and lock socket buffer locks. 862 */ 863 unp2 = unp->unp_conn; 864 if (unp2 == NULL) { 865 error = ENOTCONN; 866 break; 867 } 868 so2 = unp2->unp_socket; 869 UNP_PCB_LOCK(unp2); 870 SOCKBUF_LOCK(&so2->so_rcv); 871 if (unp2->unp_flags & UNP_WANTCRED) { 872 /* 873 * Credentials are passed only once on SOCK_STREAM. 874 */ 875 unp2->unp_flags &= ~UNP_WANTCRED; 876 control = unp_addsockcred(td, control); 877 } 878 /* 879 * Send to paired receive port, and then reduce send buffer 880 * hiwater marks to maintain backpressure. Wake up readers. 881 */ 882 if (control != NULL) { 883 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 884 control = NULL; 885 } else 886 sbappend_locked(&so2->so_rcv, m); 887 mbcnt_delta = so2->so_rcv.sb_mbcnt - unp2->unp_mbcnt; 888 unp2->unp_mbcnt = so2->so_rcv.sb_mbcnt; 889 sbcc = so2->so_rcv.sb_cc; 890 sorwakeup_locked(so2); 891 892 SOCKBUF_LOCK(&so->so_snd); 893 newhiwat = so->so_snd.sb_hiwat - (sbcc - unp2->unp_cc); 894 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 895 newhiwat, RLIM_INFINITY); 896 so->so_snd.sb_mbmax -= mbcnt_delta; 897 SOCKBUF_UNLOCK(&so->so_snd); 898 unp2->unp_cc = sbcc; 899 UNP_PCB_UNLOCK(unp2); 900 m = NULL; 901 break; 902 903 default: 904 panic("uipc_send unknown socktype"); 905 } 906 907 /* 908 * PRUS_EOF is equivalent to pru_send followed by pru_shutdown. 909 */ 910 if (flags & PRUS_EOF) { 911 UNP_PCB_LOCK(unp); 912 socantsendmore(so); 913 unp_shutdown(unp); 914 UNP_PCB_UNLOCK(unp); 915 } 916 917 if ((nam != NULL) || (flags & PRUS_EOF)) 918 UNP_GLOBAL_WUNLOCK(); 919 else 920 UNP_GLOBAL_RUNLOCK(); 921 922 if (control != NULL && error != 0) 923 unp_dispose(control); 924 925 release: 926 if (control != NULL) 927 m_freem(control); 928 if (m != NULL) 929 m_freem(m); 930 return (error); 931 } 932 933 static int 934 uipc_sense(struct socket *so, struct stat *sb) 935 { 936 struct unpcb *unp, *unp2; 937 struct socket *so2; 938 939 unp = sotounpcb(so); 940 KASSERT(unp != NULL, ("uipc_sense: unp == NULL")); 941 942 sb->st_blksize = so->so_snd.sb_hiwat; 943 UNP_GLOBAL_RLOCK(); 944 UNP_PCB_LOCK(unp); 945 unp2 = unp->unp_conn; 946 if (so->so_type == SOCK_STREAM && unp2 != NULL) { 947 so2 = unp2->unp_socket; 948 sb->st_blksize += so2->so_rcv.sb_cc; 949 } 950 sb->st_dev = NODEV; 951 if (unp->unp_ino == 0) 952 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 953 sb->st_ino = unp->unp_ino; 954 UNP_PCB_UNLOCK(unp); 955 UNP_GLOBAL_RUNLOCK(); 956 return (0); 957 } 958 959 static int 960 uipc_shutdown(struct socket *so) 961 { 962 struct unpcb *unp; 963 964 unp = sotounpcb(so); 965 KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL")); 966 967 UNP_GLOBAL_WLOCK(); 968 UNP_PCB_LOCK(unp); 969 socantsendmore(so); 970 unp_shutdown(unp); 971 UNP_PCB_UNLOCK(unp); 972 UNP_GLOBAL_WUNLOCK(); 973 return (0); 974 } 975 976 static int 977 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 978 { 979 struct unpcb *unp; 980 const struct sockaddr *sa; 981 982 unp = sotounpcb(so); 983 KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL")); 984 985 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 986 UNP_PCB_LOCK(unp); 987 if (unp->unp_addr != NULL) 988 sa = (struct sockaddr *) unp->unp_addr; 989 else 990 sa = &sun_noname; 991 bcopy(sa, *nam, sa->sa_len); 992 UNP_PCB_UNLOCK(unp); 993 return (0); 994 } 995 996 static struct pr_usrreqs uipc_usrreqs_dgram = { 997 .pru_abort = uipc_abort, 998 .pru_accept = uipc_accept, 999 .pru_attach = uipc_attach, 1000 .pru_bind = uipc_bind, 1001 .pru_connect = uipc_connect, 1002 .pru_connect2 = uipc_connect2, 1003 .pru_detach = uipc_detach, 1004 .pru_disconnect = uipc_disconnect, 1005 .pru_listen = uipc_listen, 1006 .pru_peeraddr = uipc_peeraddr, 1007 .pru_rcvd = uipc_rcvd, 1008 .pru_send = uipc_send, 1009 .pru_sense = uipc_sense, 1010 .pru_shutdown = uipc_shutdown, 1011 .pru_sockaddr = uipc_sockaddr, 1012 .pru_soreceive = soreceive_dgram, 1013 .pru_close = uipc_close, 1014 }; 1015 1016 static struct pr_usrreqs uipc_usrreqs_stream = { 1017 .pru_abort = uipc_abort, 1018 .pru_accept = uipc_accept, 1019 .pru_attach = uipc_attach, 1020 .pru_bind = uipc_bind, 1021 .pru_connect = uipc_connect, 1022 .pru_connect2 = uipc_connect2, 1023 .pru_detach = uipc_detach, 1024 .pru_disconnect = uipc_disconnect, 1025 .pru_listen = uipc_listen, 1026 .pru_peeraddr = uipc_peeraddr, 1027 .pru_rcvd = uipc_rcvd, 1028 .pru_send = uipc_send, 1029 .pru_sense = uipc_sense, 1030 .pru_shutdown = uipc_shutdown, 1031 .pru_sockaddr = uipc_sockaddr, 1032 .pru_soreceive = soreceive_generic, 1033 .pru_close = uipc_close, 1034 }; 1035 1036 static int 1037 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 1038 { 1039 struct unpcb *unp; 1040 struct xucred xu; 1041 int error, optval; 1042 1043 if (sopt->sopt_level != 0) 1044 return (EINVAL); 1045 1046 unp = sotounpcb(so); 1047 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL")); 1048 error = 0; 1049 switch (sopt->sopt_dir) { 1050 case SOPT_GET: 1051 switch (sopt->sopt_name) { 1052 case LOCAL_PEERCRED: 1053 UNP_PCB_LOCK(unp); 1054 if (unp->unp_flags & UNP_HAVEPC) 1055 xu = unp->unp_peercred; 1056 else { 1057 if (so->so_type == SOCK_STREAM) 1058 error = ENOTCONN; 1059 else 1060 error = EINVAL; 1061 } 1062 UNP_PCB_UNLOCK(unp); 1063 if (error == 0) 1064 error = sooptcopyout(sopt, &xu, sizeof(xu)); 1065 break; 1066 1067 case LOCAL_CREDS: 1068 /* Unlocked read. */ 1069 optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0; 1070 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1071 break; 1072 1073 case LOCAL_CONNWAIT: 1074 /* Unlocked read. */ 1075 optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0; 1076 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1077 break; 1078 1079 default: 1080 error = EOPNOTSUPP; 1081 break; 1082 } 1083 break; 1084 1085 case SOPT_SET: 1086 switch (sopt->sopt_name) { 1087 case LOCAL_CREDS: 1088 case LOCAL_CONNWAIT: 1089 error = sooptcopyin(sopt, &optval, sizeof(optval), 1090 sizeof(optval)); 1091 if (error) 1092 break; 1093 1094 #define OPTSET(bit) do { \ 1095 UNP_PCB_LOCK(unp); \ 1096 if (optval) \ 1097 unp->unp_flags |= bit; \ 1098 else \ 1099 unp->unp_flags &= ~bit; \ 1100 UNP_PCB_UNLOCK(unp); \ 1101 } while (0) 1102 1103 switch (sopt->sopt_name) { 1104 case LOCAL_CREDS: 1105 OPTSET(UNP_WANTCRED); 1106 break; 1107 1108 case LOCAL_CONNWAIT: 1109 OPTSET(UNP_CONNWAIT); 1110 break; 1111 1112 default: 1113 break; 1114 } 1115 break; 1116 #undef OPTSET 1117 default: 1118 error = ENOPROTOOPT; 1119 break; 1120 } 1121 break; 1122 1123 default: 1124 error = EOPNOTSUPP; 1125 break; 1126 } 1127 return (error); 1128 } 1129 1130 static int 1131 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1132 { 1133 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 1134 struct vnode *vp; 1135 struct socket *so2, *so3; 1136 struct unpcb *unp, *unp2, *unp3; 1137 int error, len, vfslocked; 1138 struct nameidata nd; 1139 char buf[SOCK_MAXADDRLEN]; 1140 struct sockaddr *sa; 1141 1142 UNP_GLOBAL_WLOCK_ASSERT(); 1143 1144 unp = sotounpcb(so); 1145 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1146 1147 if (nam->sa_len > sizeof(struct sockaddr_un)) 1148 return (EINVAL); 1149 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 1150 if (len <= 0) 1151 return (EINVAL); 1152 bcopy(soun->sun_path, buf, len); 1153 buf[len] = 0; 1154 1155 UNP_PCB_LOCK(unp); 1156 if (unp->unp_flags & UNP_CONNECTING) { 1157 UNP_PCB_UNLOCK(unp); 1158 return (EALREADY); 1159 } 1160 UNP_GLOBAL_WUNLOCK(); 1161 unp->unp_flags |= UNP_CONNECTING; 1162 UNP_PCB_UNLOCK(unp); 1163 1164 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 1165 NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, 1166 td); 1167 error = namei(&nd); 1168 if (error) 1169 vp = NULL; 1170 else 1171 vp = nd.ni_vp; 1172 ASSERT_VOP_LOCKED(vp, "unp_connect"); 1173 vfslocked = NDHASGIANT(&nd); 1174 NDFREE(&nd, NDF_ONLY_PNBUF); 1175 if (error) 1176 goto bad; 1177 1178 if (vp->v_type != VSOCK) { 1179 error = ENOTSOCK; 1180 goto bad; 1181 } 1182 #ifdef MAC 1183 error = mac_check_vnode_open(td->td_ucred, vp, VWRITE | VREAD); 1184 if (error) 1185 goto bad; 1186 #endif 1187 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 1188 if (error) 1189 goto bad; 1190 VFS_UNLOCK_GIANT(vfslocked); 1191 1192 unp = sotounpcb(so); 1193 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1194 1195 /* 1196 * Lock global lock for two reasons: make sure v_socket is stable, 1197 * and to protect simultaneous locking of multiple pcbs. 1198 */ 1199 UNP_GLOBAL_WLOCK(); 1200 so2 = vp->v_socket; 1201 if (so2 == NULL) { 1202 error = ECONNREFUSED; 1203 goto bad2; 1204 } 1205 if (so->so_type != so2->so_type) { 1206 error = EPROTOTYPE; 1207 goto bad2; 1208 } 1209 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1210 if (so2->so_options & SO_ACCEPTCONN) { 1211 /* 1212 * We can't drop the global lock here or 'so2' may 1213 * become invalid. As a result, we need to handle 1214 * possibly lock recursion in uipc_attach. 1215 */ 1216 so3 = sonewconn(so2, 0); 1217 } else 1218 so3 = NULL; 1219 if (so3 == NULL) { 1220 error = ECONNREFUSED; 1221 goto bad2; 1222 } 1223 unp = sotounpcb(so); 1224 unp2 = sotounpcb(so2); 1225 unp3 = sotounpcb(so3); 1226 UNP_PCB_LOCK(unp); 1227 UNP_PCB_LOCK(unp2); 1228 UNP_PCB_LOCK(unp3); 1229 if (unp2->unp_addr != NULL) { 1230 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 1231 unp3->unp_addr = (struct sockaddr_un *) sa; 1232 sa = NULL; 1233 } 1234 1235 /* 1236 * The connecter's (client's) credentials are copied from its 1237 * process structure at the time of connect() (which is now). 1238 */ 1239 cru2x(td->td_ucred, &unp3->unp_peercred); 1240 unp3->unp_flags |= UNP_HAVEPC; 1241 1242 /* 1243 * The receiver's (server's) credentials are copied from the 1244 * unp_peercred member of socket on which the former called 1245 * listen(); uipc_listen() cached that process's credentials 1246 * at that time so we can use them now. 1247 */ 1248 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1249 ("unp_connect: listener without cached peercred")); 1250 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1251 sizeof(unp->unp_peercred)); 1252 unp->unp_flags |= UNP_HAVEPC; 1253 if (unp2->unp_flags & UNP_WANTCRED) 1254 unp3->unp_flags |= UNP_WANTCRED; 1255 UNP_PCB_UNLOCK(unp3); 1256 UNP_PCB_UNLOCK(unp2); 1257 UNP_PCB_UNLOCK(unp); 1258 #ifdef MAC 1259 SOCK_LOCK(so); 1260 mac_set_socket_peer_from_socket(so, so3); 1261 mac_set_socket_peer_from_socket(so3, so); 1262 SOCK_UNLOCK(so); 1263 #endif 1264 1265 so2 = so3; 1266 } 1267 unp = sotounpcb(so); 1268 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1269 unp2 = sotounpcb(so2); 1270 KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL")); 1271 UNP_PCB_LOCK(unp); 1272 UNP_PCB_LOCK(unp2); 1273 error = unp_connect2(so, so2, PRU_CONNECT); 1274 UNP_PCB_UNLOCK(unp2); 1275 UNP_PCB_UNLOCK(unp); 1276 bad2: 1277 UNP_GLOBAL_WUNLOCK(); 1278 if (vfslocked) 1279 /* 1280 * Giant has been previously acquired. This means filesystem 1281 * isn't MPSAFE. Do it once again. 1282 */ 1283 mtx_lock(&Giant); 1284 bad: 1285 if (vp != NULL) 1286 vput(vp); 1287 VFS_UNLOCK_GIANT(vfslocked); 1288 free(sa, M_SONAME); 1289 UNP_GLOBAL_WLOCK(); 1290 UNP_PCB_LOCK(unp); 1291 unp->unp_flags &= ~UNP_CONNECTING; 1292 UNP_PCB_UNLOCK(unp); 1293 return (error); 1294 } 1295 1296 static int 1297 unp_connect2(struct socket *so, struct socket *so2, int req) 1298 { 1299 struct unpcb *unp; 1300 struct unpcb *unp2; 1301 1302 unp = sotounpcb(so); 1303 KASSERT(unp != NULL, ("unp_connect2: unp == NULL")); 1304 unp2 = sotounpcb(so2); 1305 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL")); 1306 1307 UNP_GLOBAL_WLOCK_ASSERT(); 1308 UNP_PCB_LOCK_ASSERT(unp); 1309 UNP_PCB_LOCK_ASSERT(unp2); 1310 1311 if (so2->so_type != so->so_type) 1312 return (EPROTOTYPE); 1313 unp->unp_conn = unp2; 1314 1315 switch (so->so_type) { 1316 case SOCK_DGRAM: 1317 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 1318 soisconnected(so); 1319 break; 1320 1321 case SOCK_STREAM: 1322 unp2->unp_conn = unp; 1323 if (req == PRU_CONNECT && 1324 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1325 soisconnecting(so); 1326 else 1327 soisconnected(so); 1328 soisconnected(so2); 1329 break; 1330 1331 default: 1332 panic("unp_connect2"); 1333 } 1334 return (0); 1335 } 1336 1337 static void 1338 unp_disconnect(struct unpcb *unp, struct unpcb *unp2) 1339 { 1340 struct socket *so; 1341 1342 KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL")); 1343 1344 UNP_GLOBAL_WLOCK_ASSERT(); 1345 UNP_PCB_LOCK_ASSERT(unp); 1346 UNP_PCB_LOCK_ASSERT(unp2); 1347 1348 unp->unp_conn = NULL; 1349 switch (unp->unp_socket->so_type) { 1350 case SOCK_DGRAM: 1351 LIST_REMOVE(unp, unp_reflink); 1352 so = unp->unp_socket; 1353 SOCK_LOCK(so); 1354 so->so_state &= ~SS_ISCONNECTED; 1355 SOCK_UNLOCK(so); 1356 break; 1357 1358 case SOCK_STREAM: 1359 soisdisconnected(unp->unp_socket); 1360 unp2->unp_conn = NULL; 1361 soisdisconnected(unp2->unp_socket); 1362 break; 1363 } 1364 } 1365 1366 /* 1367 * unp_pcblist() walks the global list of struct unpcb's to generate a 1368 * pointer list, bumping the refcount on each unpcb. It then copies them out 1369 * sequentially, validating the generation number on each to see if it has 1370 * been detached. All of this is necessary because copyout() may sleep on 1371 * disk I/O. 1372 */ 1373 static int 1374 unp_pcblist(SYSCTL_HANDLER_ARGS) 1375 { 1376 int error, i, n; 1377 int freeunp; 1378 struct unpcb *unp, **unp_list; 1379 unp_gen_t gencnt; 1380 struct xunpgen *xug; 1381 struct unp_head *head; 1382 struct xunpcb *xu; 1383 1384 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1385 1386 /* 1387 * The process of preparing the PCB list is too time-consuming and 1388 * resource-intensive to repeat twice on every request. 1389 */ 1390 if (req->oldptr == NULL) { 1391 n = unp_count; 1392 req->oldidx = 2 * (sizeof *xug) 1393 + (n + n/8) * sizeof(struct xunpcb); 1394 return (0); 1395 } 1396 1397 if (req->newptr != NULL) 1398 return (EPERM); 1399 1400 /* 1401 * OK, now we're committed to doing something. 1402 */ 1403 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1404 UNP_GLOBAL_RLOCK(); 1405 gencnt = unp_gencnt; 1406 n = unp_count; 1407 UNP_GLOBAL_RUNLOCK(); 1408 1409 xug->xug_len = sizeof *xug; 1410 xug->xug_count = n; 1411 xug->xug_gen = gencnt; 1412 xug->xug_sogen = so_gencnt; 1413 error = SYSCTL_OUT(req, xug, sizeof *xug); 1414 if (error) { 1415 free(xug, M_TEMP); 1416 return (error); 1417 } 1418 1419 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1420 1421 UNP_GLOBAL_RLOCK(); 1422 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1423 unp = LIST_NEXT(unp, unp_link)) { 1424 UNP_PCB_LOCK(unp); 1425 if (unp->unp_gencnt <= gencnt) { 1426 if (cr_cansee(req->td->td_ucred, 1427 unp->unp_socket->so_cred)) { 1428 UNP_PCB_UNLOCK(unp); 1429 continue; 1430 } 1431 unp_list[i++] = unp; 1432 unp->unp_refcount++; 1433 } 1434 UNP_PCB_UNLOCK(unp); 1435 } 1436 UNP_GLOBAL_RUNLOCK(); 1437 n = i; /* In case we lost some during malloc. */ 1438 1439 error = 0; 1440 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 1441 for (i = 0; i < n; i++) { 1442 unp = unp_list[i]; 1443 UNP_PCB_LOCK(unp); 1444 unp->unp_refcount--; 1445 if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) { 1446 xu->xu_len = sizeof *xu; 1447 xu->xu_unpp = unp; 1448 /* 1449 * XXX - need more locking here to protect against 1450 * connect/disconnect races for SMP. 1451 */ 1452 if (unp->unp_addr != NULL) 1453 bcopy(unp->unp_addr, &xu->xu_addr, 1454 unp->unp_addr->sun_len); 1455 if (unp->unp_conn != NULL && 1456 unp->unp_conn->unp_addr != NULL) 1457 bcopy(unp->unp_conn->unp_addr, 1458 &xu->xu_caddr, 1459 unp->unp_conn->unp_addr->sun_len); 1460 bcopy(unp, &xu->xu_unp, sizeof *unp); 1461 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1462 UNP_PCB_UNLOCK(unp); 1463 error = SYSCTL_OUT(req, xu, sizeof *xu); 1464 } else { 1465 freeunp = (unp->unp_refcount == 0); 1466 UNP_PCB_UNLOCK(unp); 1467 if (freeunp) { 1468 UNP_PCB_LOCK_DESTROY(unp); 1469 uma_zfree(unp_zone, unp); 1470 } 1471 } 1472 } 1473 free(xu, M_TEMP); 1474 if (!error) { 1475 /* 1476 * Give the user an updated idea of our state. If the 1477 * generation differs from what we told her before, she knows 1478 * that something happened while we were processing this 1479 * request, and it might be necessary to retry. 1480 */ 1481 xug->xug_gen = unp_gencnt; 1482 xug->xug_sogen = so_gencnt; 1483 xug->xug_count = unp_count; 1484 error = SYSCTL_OUT(req, xug, sizeof *xug); 1485 } 1486 free(unp_list, M_TEMP); 1487 free(xug, M_TEMP); 1488 return (error); 1489 } 1490 1491 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1492 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1493 "List of active local datagram sockets"); 1494 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1495 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1496 "List of active local stream sockets"); 1497 1498 static void 1499 unp_shutdown(struct unpcb *unp) 1500 { 1501 struct unpcb *unp2; 1502 struct socket *so; 1503 1504 UNP_GLOBAL_WLOCK_ASSERT(); 1505 UNP_PCB_LOCK_ASSERT(unp); 1506 1507 unp2 = unp->unp_conn; 1508 if (unp->unp_socket->so_type == SOCK_STREAM && unp2 != NULL) { 1509 so = unp2->unp_socket; 1510 if (so != NULL) 1511 socantrcvmore(so); 1512 } 1513 } 1514 1515 static void 1516 unp_drop(struct unpcb *unp, int errno) 1517 { 1518 struct socket *so = unp->unp_socket; 1519 struct unpcb *unp2; 1520 1521 UNP_GLOBAL_WLOCK_ASSERT(); 1522 UNP_PCB_LOCK_ASSERT(unp); 1523 1524 so->so_error = errno; 1525 unp2 = unp->unp_conn; 1526 if (unp2 == NULL) 1527 return; 1528 UNP_PCB_LOCK(unp2); 1529 unp_disconnect(unp, unp2); 1530 UNP_PCB_UNLOCK(unp2); 1531 } 1532 1533 static void 1534 unp_freerights(struct file **rp, int fdcount) 1535 { 1536 int i; 1537 struct file *fp; 1538 1539 for (i = 0; i < fdcount; i++) { 1540 fp = *rp; 1541 *rp++ = NULL; 1542 unp_discard(fp); 1543 } 1544 } 1545 1546 static int 1547 unp_externalize(struct mbuf *control, struct mbuf **controlp) 1548 { 1549 struct thread *td = curthread; /* XXX */ 1550 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1551 int i; 1552 int *fdp; 1553 struct file **rp; 1554 struct file *fp; 1555 void *data; 1556 socklen_t clen = control->m_len, datalen; 1557 int error, newfds; 1558 int f; 1559 u_int newlen; 1560 1561 UNP_GLOBAL_UNLOCK_ASSERT(); 1562 1563 error = 0; 1564 if (controlp != NULL) /* controlp == NULL => free control messages */ 1565 *controlp = NULL; 1566 while (cm != NULL) { 1567 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1568 error = EINVAL; 1569 break; 1570 } 1571 data = CMSG_DATA(cm); 1572 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1573 if (cm->cmsg_level == SOL_SOCKET 1574 && cm->cmsg_type == SCM_RIGHTS) { 1575 newfds = datalen / sizeof(struct file *); 1576 rp = data; 1577 1578 /* If we're not outputting the descriptors free them. */ 1579 if (error || controlp == NULL) { 1580 unp_freerights(rp, newfds); 1581 goto next; 1582 } 1583 FILEDESC_XLOCK(td->td_proc->p_fd); 1584 /* if the new FD's will not fit free them. */ 1585 if (!fdavail(td, newfds)) { 1586 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1587 error = EMSGSIZE; 1588 unp_freerights(rp, newfds); 1589 goto next; 1590 } 1591 1592 /* 1593 * Now change each pointer to an fd in the global 1594 * table to an integer that is the index to the local 1595 * fd table entry that we set up to point to the 1596 * global one we are transferring. 1597 */ 1598 newlen = newfds * sizeof(int); 1599 *controlp = sbcreatecontrol(NULL, newlen, 1600 SCM_RIGHTS, SOL_SOCKET); 1601 if (*controlp == NULL) { 1602 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1603 error = E2BIG; 1604 unp_freerights(rp, newfds); 1605 goto next; 1606 } 1607 1608 fdp = (int *) 1609 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1610 for (i = 0; i < newfds; i++) { 1611 if (fdalloc(td, 0, &f)) 1612 panic("unp_externalize fdalloc failed"); 1613 fp = *rp++; 1614 td->td_proc->p_fd->fd_ofiles[f] = fp; 1615 FILE_LOCK(fp); 1616 fp->f_msgcount--; 1617 FILE_UNLOCK(fp); 1618 UNP_GLOBAL_WLOCK(); 1619 unp_rights--; 1620 UNP_GLOBAL_WUNLOCK(); 1621 *fdp++ = f; 1622 } 1623 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1624 } else { 1625 /* We can just copy anything else across. */ 1626 if (error || controlp == NULL) 1627 goto next; 1628 *controlp = sbcreatecontrol(NULL, datalen, 1629 cm->cmsg_type, cm->cmsg_level); 1630 if (*controlp == NULL) { 1631 error = ENOBUFS; 1632 goto next; 1633 } 1634 bcopy(data, 1635 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1636 datalen); 1637 } 1638 controlp = &(*controlp)->m_next; 1639 1640 next: 1641 if (CMSG_SPACE(datalen) < clen) { 1642 clen -= CMSG_SPACE(datalen); 1643 cm = (struct cmsghdr *) 1644 ((caddr_t)cm + CMSG_SPACE(datalen)); 1645 } else { 1646 clen = 0; 1647 cm = NULL; 1648 } 1649 } 1650 1651 m_freem(control); 1652 return (error); 1653 } 1654 1655 static void 1656 unp_zone_change(void *tag) 1657 { 1658 1659 uma_zone_set_max(unp_zone, maxsockets); 1660 } 1661 1662 static void 1663 unp_init(void) 1664 { 1665 1666 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1667 NULL, NULL, UMA_ALIGN_PTR, 0); 1668 if (unp_zone == NULL) 1669 panic("unp_init"); 1670 uma_zone_set_max(unp_zone, maxsockets); 1671 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change, 1672 NULL, EVENTHANDLER_PRI_ANY); 1673 LIST_INIT(&unp_dhead); 1674 LIST_INIT(&unp_shead); 1675 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1676 UNP_GLOBAL_LOCK_INIT(); 1677 } 1678 1679 static int 1680 unp_internalize(struct mbuf **controlp, struct thread *td) 1681 { 1682 struct mbuf *control = *controlp; 1683 struct proc *p = td->td_proc; 1684 struct filedesc *fdescp = p->p_fd; 1685 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1686 struct cmsgcred *cmcred; 1687 struct file **rp; 1688 struct file *fp; 1689 struct timeval *tv; 1690 int i, fd, *fdp; 1691 void *data; 1692 socklen_t clen = control->m_len, datalen; 1693 int error, oldfds; 1694 u_int newlen; 1695 1696 UNP_GLOBAL_UNLOCK_ASSERT(); 1697 1698 error = 0; 1699 *controlp = NULL; 1700 while (cm != NULL) { 1701 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1702 || cm->cmsg_len > clen) { 1703 error = EINVAL; 1704 goto out; 1705 } 1706 data = CMSG_DATA(cm); 1707 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1708 1709 switch (cm->cmsg_type) { 1710 /* 1711 * Fill in credential information. 1712 */ 1713 case SCM_CREDS: 1714 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1715 SCM_CREDS, SOL_SOCKET); 1716 if (*controlp == NULL) { 1717 error = ENOBUFS; 1718 goto out; 1719 } 1720 cmcred = (struct cmsgcred *) 1721 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1722 cmcred->cmcred_pid = p->p_pid; 1723 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1724 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1725 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1726 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1727 CMGROUP_MAX); 1728 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1729 cmcred->cmcred_groups[i] = 1730 td->td_ucred->cr_groups[i]; 1731 break; 1732 1733 case SCM_RIGHTS: 1734 oldfds = datalen / sizeof (int); 1735 /* 1736 * Check that all the FDs passed in refer to legal 1737 * files. If not, reject the entire operation. 1738 */ 1739 fdp = data; 1740 FILEDESC_SLOCK(fdescp); 1741 for (i = 0; i < oldfds; i++) { 1742 fd = *fdp++; 1743 if ((unsigned)fd >= fdescp->fd_nfiles || 1744 fdescp->fd_ofiles[fd] == NULL) { 1745 FILEDESC_SUNLOCK(fdescp); 1746 error = EBADF; 1747 goto out; 1748 } 1749 fp = fdescp->fd_ofiles[fd]; 1750 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1751 FILEDESC_SUNLOCK(fdescp); 1752 error = EOPNOTSUPP; 1753 goto out; 1754 } 1755 1756 } 1757 1758 /* 1759 * Now replace the integer FDs with pointers to the 1760 * associated global file table entry.. 1761 */ 1762 newlen = oldfds * sizeof(struct file *); 1763 *controlp = sbcreatecontrol(NULL, newlen, 1764 SCM_RIGHTS, SOL_SOCKET); 1765 if (*controlp == NULL) { 1766 FILEDESC_SUNLOCK(fdescp); 1767 error = E2BIG; 1768 goto out; 1769 } 1770 fdp = data; 1771 rp = (struct file **) 1772 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1773 for (i = 0; i < oldfds; i++) { 1774 fp = fdescp->fd_ofiles[*fdp++]; 1775 *rp++ = fp; 1776 FILE_LOCK(fp); 1777 fp->f_count++; 1778 fp->f_msgcount++; 1779 FILE_UNLOCK(fp); 1780 UNP_GLOBAL_WLOCK(); 1781 unp_rights++; 1782 UNP_GLOBAL_WUNLOCK(); 1783 } 1784 FILEDESC_SUNLOCK(fdescp); 1785 break; 1786 1787 case SCM_TIMESTAMP: 1788 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1789 SCM_TIMESTAMP, SOL_SOCKET); 1790 if (*controlp == NULL) { 1791 error = ENOBUFS; 1792 goto out; 1793 } 1794 tv = (struct timeval *) 1795 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1796 microtime(tv); 1797 break; 1798 1799 default: 1800 error = EINVAL; 1801 goto out; 1802 } 1803 1804 controlp = &(*controlp)->m_next; 1805 if (CMSG_SPACE(datalen) < clen) { 1806 clen -= CMSG_SPACE(datalen); 1807 cm = (struct cmsghdr *) 1808 ((caddr_t)cm + CMSG_SPACE(datalen)); 1809 } else { 1810 clen = 0; 1811 cm = NULL; 1812 } 1813 } 1814 1815 out: 1816 m_freem(control); 1817 return (error); 1818 } 1819 1820 static struct mbuf * 1821 unp_addsockcred(struct thread *td, struct mbuf *control) 1822 { 1823 struct mbuf *m, *n, *n_prev; 1824 struct sockcred *sc; 1825 const struct cmsghdr *cm; 1826 int ngroups; 1827 int i; 1828 1829 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); 1830 m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET); 1831 if (m == NULL) 1832 return (control); 1833 1834 sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *)); 1835 sc->sc_uid = td->td_ucred->cr_ruid; 1836 sc->sc_euid = td->td_ucred->cr_uid; 1837 sc->sc_gid = td->td_ucred->cr_rgid; 1838 sc->sc_egid = td->td_ucred->cr_gid; 1839 sc->sc_ngroups = ngroups; 1840 for (i = 0; i < sc->sc_ngroups; i++) 1841 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 1842 1843 /* 1844 * Unlink SCM_CREDS control messages (struct cmsgcred), since just 1845 * created SCM_CREDS control message (struct sockcred) has another 1846 * format. 1847 */ 1848 if (control != NULL) 1849 for (n = control, n_prev = NULL; n != NULL;) { 1850 cm = mtod(n, struct cmsghdr *); 1851 if (cm->cmsg_level == SOL_SOCKET && 1852 cm->cmsg_type == SCM_CREDS) { 1853 if (n_prev == NULL) 1854 control = n->m_next; 1855 else 1856 n_prev->m_next = n->m_next; 1857 n = m_free(n); 1858 } else { 1859 n_prev = n; 1860 n = n->m_next; 1861 } 1862 } 1863 1864 /* Prepend it to the head. */ 1865 m->m_next = control; 1866 return (m); 1867 } 1868 1869 /* 1870 * unp_defer indicates whether additional work has been defered for a future 1871 * pass through unp_gc(). It is thread local and does not require explicit 1872 * synchronization. 1873 */ 1874 static int unp_defer; 1875 1876 static int unp_taskcount; 1877 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, ""); 1878 1879 static int unp_recycled; 1880 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, ""); 1881 1882 static void 1883 unp_gc(__unused void *arg, int pending) 1884 { 1885 struct file *fp, *nextfp; 1886 struct socket *so; 1887 struct socket *soa; 1888 struct file **extra_ref, **fpp; 1889 int nunref, i; 1890 int nfiles_snap; 1891 int nfiles_slack = 20; 1892 1893 unp_taskcount++; 1894 unp_defer = 0; 1895 1896 /* 1897 * Before going through all this, set all FDs to be NOT deferred and 1898 * NOT externally accessible. 1899 */ 1900 sx_slock(&filelist_lock); 1901 LIST_FOREACH(fp, &filehead, f_list) 1902 fp->f_gcflag &= ~(FMARK|FDEFER); 1903 do { 1904 KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer)); 1905 LIST_FOREACH(fp, &filehead, f_list) { 1906 FILE_LOCK(fp); 1907 /* 1908 * If the file is not open, skip it -- could be a 1909 * file in the process of being opened, or in the 1910 * process of being closed. If the file is 1911 * "closing", it may have been marked for deferred 1912 * consideration. Clear the flag now if so. 1913 */ 1914 if (fp->f_count == 0) { 1915 if (fp->f_gcflag & FDEFER) 1916 unp_defer--; 1917 fp->f_gcflag &= ~(FMARK|FDEFER); 1918 FILE_UNLOCK(fp); 1919 continue; 1920 } 1921 1922 /* 1923 * If we already marked it as 'defer' in a 1924 * previous pass, then try to process it this 1925 * time and un-mark it. 1926 */ 1927 if (fp->f_gcflag & FDEFER) { 1928 fp->f_gcflag &= ~FDEFER; 1929 unp_defer--; 1930 } else { 1931 /* 1932 * If it's not deferred, then check if it's 1933 * already marked.. if so skip it 1934 */ 1935 if (fp->f_gcflag & FMARK) { 1936 FILE_UNLOCK(fp); 1937 continue; 1938 } 1939 1940 /* 1941 * If all references are from messages in 1942 * transit, then skip it. it's not externally 1943 * accessible. 1944 */ 1945 if (fp->f_count == fp->f_msgcount) { 1946 FILE_UNLOCK(fp); 1947 continue; 1948 } 1949 1950 /* 1951 * If it got this far then it must be 1952 * externally accessible. 1953 */ 1954 fp->f_gcflag |= FMARK; 1955 } 1956 1957 /* 1958 * Either it was deferred, or it is externally 1959 * accessible and not already marked so. Now check 1960 * if it is possibly one of OUR sockets. 1961 */ 1962 if (fp->f_type != DTYPE_SOCKET || 1963 (so = fp->f_data) == NULL) { 1964 FILE_UNLOCK(fp); 1965 continue; 1966 } 1967 1968 if (so->so_proto->pr_domain != &localdomain || 1969 (so->so_proto->pr_flags & PR_RIGHTS) == 0) { 1970 FILE_UNLOCK(fp); 1971 continue; 1972 } 1973 1974 /* 1975 * Tell any other threads that do a subsequent 1976 * fdrop() that we are scanning the message 1977 * buffers. 1978 */ 1979 fp->f_gcflag |= FWAIT; 1980 FILE_UNLOCK(fp); 1981 1982 /* 1983 * So, Ok, it's one of our sockets and it IS 1984 * externally accessible (or was deferred). Now we 1985 * look to see if we hold any file descriptors in its 1986 * message buffers. Follow those links and mark them 1987 * as accessible too. 1988 */ 1989 SOCKBUF_LOCK(&so->so_rcv); 1990 unp_scan(so->so_rcv.sb_mb, unp_mark); 1991 SOCKBUF_UNLOCK(&so->so_rcv); 1992 1993 /* 1994 * If socket is in listening state, then sockets 1995 * in its accept queue are accessible, and so 1996 * are any descriptors in those sockets' receive 1997 * queues. 1998 */ 1999 ACCEPT_LOCK(); 2000 TAILQ_FOREACH(soa, &so->so_comp, so_list) { 2001 SOCKBUF_LOCK(&soa->so_rcv); 2002 unp_scan(soa->so_rcv.sb_mb, unp_mark); 2003 SOCKBUF_UNLOCK(&soa->so_rcv); 2004 } 2005 ACCEPT_UNLOCK(); 2006 2007 /* 2008 * Wake up any threads waiting in fdrop(). 2009 */ 2010 FILE_LOCK(fp); 2011 fp->f_gcflag &= ~FWAIT; 2012 wakeup(&fp->f_gcflag); 2013 FILE_UNLOCK(fp); 2014 } 2015 } while (unp_defer); 2016 sx_sunlock(&filelist_lock); 2017 2018 /* 2019 * XXXRW: The following comments need updating for a post-SMPng and 2020 * deferred unp_gc() world, but are still generally accurate. 2021 * 2022 * We grab an extra reference to each of the file table entries that 2023 * are not otherwise accessible and then free the rights that are 2024 * stored in messages on them. 2025 * 2026 * The bug in the orginal code is a little tricky, so I'll describe 2027 * what's wrong with it here. 2028 * 2029 * It is incorrect to simply unp_discard each entry for f_msgcount 2030 * times -- consider the case of sockets A and B that contain 2031 * references to each other. On a last close of some other socket, 2032 * we trigger a gc since the number of outstanding rights (unp_rights) 2033 * is non-zero. If during the sweep phase the gc code unp_discards, 2034 * we end up doing a (full) closef on the descriptor. A closef on A 2035 * results in the following chain. Closef calls soo_close, which 2036 * calls soclose. Soclose calls first (through the switch 2037 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2038 * returns because the previous instance had set unp_gcing, and we 2039 * return all the way back to soclose, which marks the socket with 2040 * SS_NOFDREF, and then calls sofree. Sofree calls sorflush to free 2041 * up the rights that are queued in messages on the socket A, i.e., 2042 * the reference on B. The sorflush calls via the dom_dispose switch 2043 * unp_dispose, which unp_scans with unp_discard. This second 2044 * instance of unp_discard just calls closef on B. 2045 * 2046 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2047 * which results in another closef on A. Unfortunately, A is already 2048 * being closed, and the descriptor has already been marked with 2049 * SS_NOFDREF, and soclose panics at this point. 2050 * 2051 * Here, we first take an extra reference to each inaccessible 2052 * descriptor. Then, we call sorflush ourself, since we know it is a 2053 * Unix domain socket anyhow. After we destroy all the rights 2054 * carried in messages, we do a last closef to get rid of our extra 2055 * reference. This is the last close, and the unp_detach etc will 2056 * shut down the socket. 2057 * 2058 * 91/09/19, bsy@cs.cmu.edu 2059 */ 2060 again: 2061 nfiles_snap = openfiles + nfiles_slack; /* some slack */ 2062 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 2063 M_WAITOK); 2064 sx_slock(&filelist_lock); 2065 if (nfiles_snap < openfiles) { 2066 sx_sunlock(&filelist_lock); 2067 free(extra_ref, M_TEMP); 2068 nfiles_slack += 20; 2069 goto again; 2070 } 2071 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 2072 fp != NULL; fp = nextfp) { 2073 nextfp = LIST_NEXT(fp, f_list); 2074 FILE_LOCK(fp); 2075 2076 /* 2077 * If it's not open, skip it 2078 */ 2079 if (fp->f_count == 0) { 2080 FILE_UNLOCK(fp); 2081 continue; 2082 } 2083 2084 /* 2085 * If all refs are from msgs, and it's not marked accessible 2086 * then it must be referenced from some unreachable cycle of 2087 * (shut-down) FDs, so include it in our list of FDs to 2088 * remove. 2089 */ 2090 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 2091 *fpp++ = fp; 2092 nunref++; 2093 fp->f_count++; 2094 } 2095 FILE_UNLOCK(fp); 2096 } 2097 sx_sunlock(&filelist_lock); 2098 2099 /* 2100 * For each FD on our hit list, do the following two things: 2101 */ 2102 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2103 struct file *tfp = *fpp; 2104 FILE_LOCK(tfp); 2105 if (tfp->f_type == DTYPE_SOCKET && 2106 tfp->f_data != NULL) { 2107 FILE_UNLOCK(tfp); 2108 sorflush(tfp->f_data); 2109 } else { 2110 FILE_UNLOCK(tfp); 2111 } 2112 } 2113 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2114 closef(*fpp, (struct thread *) NULL); 2115 unp_recycled++; 2116 } 2117 free(extra_ref, M_TEMP); 2118 } 2119 2120 static void 2121 unp_dispose(struct mbuf *m) 2122 { 2123 2124 if (m) 2125 unp_scan(m, unp_discard); 2126 } 2127 2128 static void 2129 unp_scan(struct mbuf *m0, void (*op)(struct file *)) 2130 { 2131 struct mbuf *m; 2132 struct file **rp; 2133 struct cmsghdr *cm; 2134 void *data; 2135 int i; 2136 socklen_t clen, datalen; 2137 int qfds; 2138 2139 while (m0 != NULL) { 2140 for (m = m0; m; m = m->m_next) { 2141 if (m->m_type != MT_CONTROL) 2142 continue; 2143 2144 cm = mtod(m, struct cmsghdr *); 2145 clen = m->m_len; 2146 2147 while (cm != NULL) { 2148 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 2149 break; 2150 2151 data = CMSG_DATA(cm); 2152 datalen = (caddr_t)cm + cm->cmsg_len 2153 - (caddr_t)data; 2154 2155 if (cm->cmsg_level == SOL_SOCKET && 2156 cm->cmsg_type == SCM_RIGHTS) { 2157 qfds = datalen / sizeof (struct file *); 2158 rp = data; 2159 for (i = 0; i < qfds; i++) 2160 (*op)(*rp++); 2161 } 2162 2163 if (CMSG_SPACE(datalen) < clen) { 2164 clen -= CMSG_SPACE(datalen); 2165 cm = (struct cmsghdr *) 2166 ((caddr_t)cm + CMSG_SPACE(datalen)); 2167 } else { 2168 clen = 0; 2169 cm = NULL; 2170 } 2171 } 2172 } 2173 m0 = m0->m_act; 2174 } 2175 } 2176 2177 static void 2178 unp_mark(struct file *fp) 2179 { 2180 2181 /* XXXRW: Should probably assert file list lock here. */ 2182 2183 if (fp->f_gcflag & FMARK) 2184 return; 2185 unp_defer++; 2186 fp->f_gcflag |= (FMARK|FDEFER); 2187 } 2188 2189 static void 2190 unp_discard(struct file *fp) 2191 { 2192 2193 UNP_GLOBAL_WLOCK(); 2194 FILE_LOCK(fp); 2195 fp->f_msgcount--; 2196 unp_rights--; 2197 FILE_UNLOCK(fp); 2198 UNP_GLOBAL_WUNLOCK(); 2199 (void) closef(fp, (struct thread *)NULL); 2200 } 2201 2202 #ifdef DDB 2203 static void 2204 db_print_indent(int indent) 2205 { 2206 int i; 2207 2208 for (i = 0; i < indent; i++) 2209 db_printf(" "); 2210 } 2211 2212 static void 2213 db_print_unpflags(int unp_flags) 2214 { 2215 int comma; 2216 2217 comma = 0; 2218 if (unp_flags & UNP_HAVEPC) { 2219 db_printf("%sUNP_HAVEPC", comma ? ", " : ""); 2220 comma = 1; 2221 } 2222 if (unp_flags & UNP_HAVEPCCACHED) { 2223 db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : ""); 2224 comma = 1; 2225 } 2226 if (unp_flags & UNP_WANTCRED) { 2227 db_printf("%sUNP_WANTCRED", comma ? ", " : ""); 2228 comma = 1; 2229 } 2230 if (unp_flags & UNP_CONNWAIT) { 2231 db_printf("%sUNP_CONNWAIT", comma ? ", " : ""); 2232 comma = 1; 2233 } 2234 if (unp_flags & UNP_CONNECTING) { 2235 db_printf("%sUNP_CONNECTING", comma ? ", " : ""); 2236 comma = 1; 2237 } 2238 if (unp_flags & UNP_BINDING) { 2239 db_printf("%sUNP_BINDING", comma ? ", " : ""); 2240 comma = 1; 2241 } 2242 } 2243 2244 static void 2245 db_print_xucred(int indent, struct xucred *xu) 2246 { 2247 int comma, i; 2248 2249 db_print_indent(indent); 2250 db_printf("cr_version: %u cr_uid: %u cr_ngroups: %d\n", 2251 xu->cr_version, xu->cr_uid, xu->cr_ngroups); 2252 db_print_indent(indent); 2253 db_printf("cr_groups: "); 2254 comma = 0; 2255 for (i = 0; i < xu->cr_ngroups; i++) { 2256 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]); 2257 comma = 1; 2258 } 2259 db_printf("\n"); 2260 } 2261 2262 static void 2263 db_print_unprefs(int indent, struct unp_head *uh) 2264 { 2265 struct unpcb *unp; 2266 int counter; 2267 2268 counter = 0; 2269 LIST_FOREACH(unp, uh, unp_reflink) { 2270 if (counter % 4 == 0) 2271 db_print_indent(indent); 2272 db_printf("%p ", unp); 2273 if (counter % 4 == 3) 2274 db_printf("\n"); 2275 counter++; 2276 } 2277 if (counter != 0 && counter % 4 != 0) 2278 db_printf("\n"); 2279 } 2280 2281 DB_SHOW_COMMAND(unpcb, db_show_unpcb) 2282 { 2283 struct unpcb *unp; 2284 2285 if (!have_addr) { 2286 db_printf("usage: show unpcb <addr>\n"); 2287 return; 2288 } 2289 unp = (struct unpcb *)addr; 2290 2291 db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket, 2292 unp->unp_vnode); 2293 2294 db_printf("unp_ino: %d unp_conn: %p\n", unp->unp_ino, 2295 unp->unp_conn); 2296 2297 db_printf("unp_refs:\n"); 2298 db_print_unprefs(2, &unp->unp_refs); 2299 2300 /* XXXRW: Would be nice to print the full address, if any. */ 2301 db_printf("unp_addr: %p\n", unp->unp_addr); 2302 2303 db_printf("unp_cc: %d unp_mbcnt: %d unp_gencnt: %llu\n", 2304 unp->unp_cc, unp->unp_mbcnt, 2305 (unsigned long long)unp->unp_gencnt); 2306 2307 db_printf("unp_flags: %x (", unp->unp_flags); 2308 db_print_unpflags(unp->unp_flags); 2309 db_printf(")\n"); 2310 2311 db_printf("unp_peercred:\n"); 2312 db_print_xucred(2, &unp->unp_peercred); 2313 2314 db_printf("unp_refcount: %u\n", unp->unp_refcount); 2315 } 2316 #endif
Cache object: ec935612905543fdd82fc8207c0d4950
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