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 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_delta, 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_delta = 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_delta; 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_dgram = { 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_soreceive = soreceive_dgram, 1010 .pru_close = uipc_close, 1011 }; 1012 1013 static struct pr_usrreqs uipc_usrreqs_stream = { 1014 .pru_abort = uipc_abort, 1015 .pru_accept = uipc_accept, 1016 .pru_attach = uipc_attach, 1017 .pru_bind = uipc_bind, 1018 .pru_connect = uipc_connect, 1019 .pru_connect2 = uipc_connect2, 1020 .pru_detach = uipc_detach, 1021 .pru_disconnect = uipc_disconnect, 1022 .pru_listen = uipc_listen, 1023 .pru_peeraddr = uipc_peeraddr, 1024 .pru_rcvd = uipc_rcvd, 1025 .pru_send = uipc_send, 1026 .pru_sense = uipc_sense, 1027 .pru_shutdown = uipc_shutdown, 1028 .pru_sockaddr = uipc_sockaddr, 1029 .pru_soreceive = soreceive_generic, 1030 .pru_close = uipc_close, 1031 }; 1032 1033 static int 1034 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 1035 { 1036 struct unpcb *unp; 1037 struct xucred xu; 1038 int error, optval; 1039 1040 if (sopt->sopt_level != 0) 1041 return (EINVAL); 1042 1043 unp = sotounpcb(so); 1044 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL")); 1045 error = 0; 1046 switch (sopt->sopt_dir) { 1047 case SOPT_GET: 1048 switch (sopt->sopt_name) { 1049 case LOCAL_PEERCRED: 1050 UNP_PCB_LOCK(unp); 1051 if (unp->unp_flags & UNP_HAVEPC) 1052 xu = unp->unp_peercred; 1053 else { 1054 if (so->so_type == SOCK_STREAM) 1055 error = ENOTCONN; 1056 else 1057 error = EINVAL; 1058 } 1059 UNP_PCB_UNLOCK(unp); 1060 if (error == 0) 1061 error = sooptcopyout(sopt, &xu, sizeof(xu)); 1062 break; 1063 1064 case LOCAL_CREDS: 1065 /* Unlocked read. */ 1066 optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0; 1067 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1068 break; 1069 1070 case LOCAL_CONNWAIT: 1071 /* Unlocked read. */ 1072 optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0; 1073 error = sooptcopyout(sopt, &optval, sizeof(optval)); 1074 break; 1075 1076 default: 1077 error = EOPNOTSUPP; 1078 break; 1079 } 1080 break; 1081 1082 case SOPT_SET: 1083 switch (sopt->sopt_name) { 1084 case LOCAL_CREDS: 1085 case LOCAL_CONNWAIT: 1086 error = sooptcopyin(sopt, &optval, sizeof(optval), 1087 sizeof(optval)); 1088 if (error) 1089 break; 1090 1091 #define OPTSET(bit) do { \ 1092 UNP_PCB_LOCK(unp); \ 1093 if (optval) \ 1094 unp->unp_flags |= bit; \ 1095 else \ 1096 unp->unp_flags &= ~bit; \ 1097 UNP_PCB_UNLOCK(unp); \ 1098 } while (0) 1099 1100 switch (sopt->sopt_name) { 1101 case LOCAL_CREDS: 1102 OPTSET(UNP_WANTCRED); 1103 break; 1104 1105 case LOCAL_CONNWAIT: 1106 OPTSET(UNP_CONNWAIT); 1107 break; 1108 1109 default: 1110 break; 1111 } 1112 break; 1113 #undef OPTSET 1114 default: 1115 error = ENOPROTOOPT; 1116 break; 1117 } 1118 break; 1119 1120 default: 1121 error = EOPNOTSUPP; 1122 break; 1123 } 1124 return (error); 1125 } 1126 1127 static int 1128 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 1129 { 1130 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 1131 struct vnode *vp; 1132 struct socket *so2, *so3; 1133 struct unpcb *unp, *unp2, *unp3; 1134 int error, len, vfslocked; 1135 struct nameidata nd; 1136 char buf[SOCK_MAXADDRLEN]; 1137 struct sockaddr *sa; 1138 1139 UNP_GLOBAL_WLOCK_ASSERT(); 1140 1141 unp = sotounpcb(so); 1142 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1143 1144 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 1145 if (len <= 0) 1146 return (EINVAL); 1147 strlcpy(buf, soun->sun_path, len + 1); 1148 1149 UNP_PCB_LOCK(unp); 1150 if (unp->unp_flags & UNP_CONNECTING) { 1151 UNP_PCB_UNLOCK(unp); 1152 return (EALREADY); 1153 } 1154 UNP_GLOBAL_WUNLOCK(); 1155 unp->unp_flags |= UNP_CONNECTING; 1156 UNP_PCB_UNLOCK(unp); 1157 1158 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 1159 NDINIT(&nd, LOOKUP, MPSAFE | FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, 1160 td); 1161 error = namei(&nd); 1162 if (error) 1163 vp = NULL; 1164 else 1165 vp = nd.ni_vp; 1166 ASSERT_VOP_LOCKED(vp, "unp_connect"); 1167 vfslocked = NDHASGIANT(&nd); 1168 NDFREE(&nd, NDF_ONLY_PNBUF); 1169 if (error) 1170 goto bad; 1171 1172 if (vp->v_type != VSOCK) { 1173 error = ENOTSOCK; 1174 goto bad; 1175 } 1176 #ifdef MAC 1177 error = mac_check_vnode_open(td->td_ucred, vp, VWRITE | VREAD); 1178 if (error) 1179 goto bad; 1180 #endif 1181 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 1182 if (error) 1183 goto bad; 1184 VFS_UNLOCK_GIANT(vfslocked); 1185 1186 unp = sotounpcb(so); 1187 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1188 1189 /* 1190 * Lock global lock for two reasons: make sure v_socket is stable, 1191 * and to protect simultaneous locking of multiple pcbs. 1192 */ 1193 UNP_GLOBAL_WLOCK(); 1194 so2 = vp->v_socket; 1195 if (so2 == NULL) { 1196 error = ECONNREFUSED; 1197 goto bad2; 1198 } 1199 if (so->so_type != so2->so_type) { 1200 error = EPROTOTYPE; 1201 goto bad2; 1202 } 1203 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 1204 if (so2->so_options & SO_ACCEPTCONN) { 1205 /* 1206 * We can't drop the global lock here or 'so2' may 1207 * become invalid. As a result, we need to handle 1208 * possibly lock recursion in uipc_attach. 1209 */ 1210 so3 = sonewconn(so2, 0); 1211 } else 1212 so3 = NULL; 1213 if (so3 == NULL) { 1214 error = ECONNREFUSED; 1215 goto bad2; 1216 } 1217 unp = sotounpcb(so); 1218 unp2 = sotounpcb(so2); 1219 unp3 = sotounpcb(so3); 1220 UNP_PCB_LOCK(unp); 1221 UNP_PCB_LOCK(unp2); 1222 UNP_PCB_LOCK(unp3); 1223 if (unp2->unp_addr != NULL) { 1224 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 1225 unp3->unp_addr = (struct sockaddr_un *) sa; 1226 sa = NULL; 1227 } 1228 1229 /* 1230 * The connecter's (client's) credentials are copied from its 1231 * process structure at the time of connect() (which is now). 1232 */ 1233 cru2x(td->td_ucred, &unp3->unp_peercred); 1234 unp3->unp_flags |= UNP_HAVEPC; 1235 1236 /* 1237 * The receiver's (server's) credentials are copied from the 1238 * unp_peercred member of socket on which the former called 1239 * listen(); uipc_listen() cached that process's credentials 1240 * at that time so we can use them now. 1241 */ 1242 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 1243 ("unp_connect: listener without cached peercred")); 1244 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 1245 sizeof(unp->unp_peercred)); 1246 unp->unp_flags |= UNP_HAVEPC; 1247 if (unp2->unp_flags & UNP_WANTCRED) 1248 unp3->unp_flags |= UNP_WANTCRED; 1249 UNP_PCB_UNLOCK(unp3); 1250 UNP_PCB_UNLOCK(unp2); 1251 UNP_PCB_UNLOCK(unp); 1252 #ifdef MAC 1253 SOCK_LOCK(so); 1254 mac_set_socket_peer_from_socket(so, so3); 1255 mac_set_socket_peer_from_socket(so3, so); 1256 SOCK_UNLOCK(so); 1257 #endif 1258 1259 so2 = so3; 1260 } 1261 unp = sotounpcb(so); 1262 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 1263 unp2 = sotounpcb(so2); 1264 KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL")); 1265 UNP_PCB_LOCK(unp); 1266 UNP_PCB_LOCK(unp2); 1267 error = unp_connect2(so, so2, PRU_CONNECT); 1268 UNP_PCB_UNLOCK(unp2); 1269 UNP_PCB_UNLOCK(unp); 1270 bad2: 1271 UNP_GLOBAL_WUNLOCK(); 1272 if (vfslocked) 1273 /* 1274 * Giant has been previously acquired. This means filesystem 1275 * isn't MPSAFE. Do it once again. 1276 */ 1277 mtx_lock(&Giant); 1278 bad: 1279 if (vp != NULL) 1280 vput(vp); 1281 VFS_UNLOCK_GIANT(vfslocked); 1282 free(sa, M_SONAME); 1283 UNP_GLOBAL_WLOCK(); 1284 UNP_PCB_LOCK(unp); 1285 unp->unp_flags &= ~UNP_CONNECTING; 1286 UNP_PCB_UNLOCK(unp); 1287 return (error); 1288 } 1289 1290 static int 1291 unp_connect2(struct socket *so, struct socket *so2, int req) 1292 { 1293 struct unpcb *unp; 1294 struct unpcb *unp2; 1295 1296 unp = sotounpcb(so); 1297 KASSERT(unp != NULL, ("unp_connect2: unp == NULL")); 1298 unp2 = sotounpcb(so2); 1299 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL")); 1300 1301 UNP_GLOBAL_WLOCK_ASSERT(); 1302 UNP_PCB_LOCK_ASSERT(unp); 1303 UNP_PCB_LOCK_ASSERT(unp2); 1304 1305 if (so2->so_type != so->so_type) 1306 return (EPROTOTYPE); 1307 unp->unp_conn = unp2; 1308 1309 switch (so->so_type) { 1310 case SOCK_DGRAM: 1311 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 1312 soisconnected(so); 1313 break; 1314 1315 case SOCK_STREAM: 1316 unp2->unp_conn = unp; 1317 if (req == PRU_CONNECT && 1318 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1319 soisconnecting(so); 1320 else 1321 soisconnected(so); 1322 soisconnected(so2); 1323 break; 1324 1325 default: 1326 panic("unp_connect2"); 1327 } 1328 return (0); 1329 } 1330 1331 static void 1332 unp_disconnect(struct unpcb *unp, struct unpcb *unp2) 1333 { 1334 struct socket *so; 1335 1336 KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL")); 1337 1338 UNP_GLOBAL_WLOCK_ASSERT(); 1339 UNP_PCB_LOCK_ASSERT(unp); 1340 UNP_PCB_LOCK_ASSERT(unp2); 1341 1342 unp->unp_conn = NULL; 1343 switch (unp->unp_socket->so_type) { 1344 case SOCK_DGRAM: 1345 LIST_REMOVE(unp, unp_reflink); 1346 so = unp->unp_socket; 1347 SOCK_LOCK(so); 1348 so->so_state &= ~SS_ISCONNECTED; 1349 SOCK_UNLOCK(so); 1350 break; 1351 1352 case SOCK_STREAM: 1353 soisdisconnected(unp->unp_socket); 1354 unp2->unp_conn = NULL; 1355 soisdisconnected(unp2->unp_socket); 1356 break; 1357 } 1358 } 1359 1360 /* 1361 * unp_pcblist() walks the global list of struct unpcb's to generate a 1362 * pointer list, bumping the refcount on each unpcb. It then copies them out 1363 * sequentially, validating the generation number on each to see if it has 1364 * been detached. All of this is necessary because copyout() may sleep on 1365 * disk I/O. 1366 */ 1367 static int 1368 unp_pcblist(SYSCTL_HANDLER_ARGS) 1369 { 1370 int error, i, n; 1371 int freeunp; 1372 struct unpcb *unp, **unp_list; 1373 unp_gen_t gencnt; 1374 struct xunpgen *xug; 1375 struct unp_head *head; 1376 struct xunpcb *xu; 1377 1378 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1379 1380 /* 1381 * The process of preparing the PCB list is too time-consuming and 1382 * resource-intensive to repeat twice on every request. 1383 */ 1384 if (req->oldptr == NULL) { 1385 n = unp_count; 1386 req->oldidx = 2 * (sizeof *xug) 1387 + (n + n/8) * sizeof(struct xunpcb); 1388 return (0); 1389 } 1390 1391 if (req->newptr != NULL) 1392 return (EPERM); 1393 1394 /* 1395 * OK, now we're committed to doing something. 1396 */ 1397 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1398 UNP_GLOBAL_RLOCK(); 1399 gencnt = unp_gencnt; 1400 n = unp_count; 1401 UNP_GLOBAL_RUNLOCK(); 1402 1403 xug->xug_len = sizeof *xug; 1404 xug->xug_count = n; 1405 xug->xug_gen = gencnt; 1406 xug->xug_sogen = so_gencnt; 1407 error = SYSCTL_OUT(req, xug, sizeof *xug); 1408 if (error) { 1409 free(xug, M_TEMP); 1410 return (error); 1411 } 1412 1413 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1414 1415 UNP_GLOBAL_RLOCK(); 1416 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1417 unp = LIST_NEXT(unp, unp_link)) { 1418 UNP_PCB_LOCK(unp); 1419 if (unp->unp_gencnt <= gencnt) { 1420 if (cr_cansee(req->td->td_ucred, 1421 unp->unp_socket->so_cred)) { 1422 UNP_PCB_UNLOCK(unp); 1423 continue; 1424 } 1425 unp_list[i++] = unp; 1426 unp->unp_refcount++; 1427 } 1428 UNP_PCB_UNLOCK(unp); 1429 } 1430 UNP_GLOBAL_RUNLOCK(); 1431 n = i; /* In case we lost some during malloc. */ 1432 1433 error = 0; 1434 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 1435 for (i = 0; i < n; i++) { 1436 unp = unp_list[i]; 1437 UNP_PCB_LOCK(unp); 1438 unp->unp_refcount--; 1439 if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) { 1440 xu->xu_len = sizeof *xu; 1441 xu->xu_unpp = unp; 1442 /* 1443 * XXX - need more locking here to protect against 1444 * connect/disconnect races for SMP. 1445 */ 1446 if (unp->unp_addr != NULL) 1447 bcopy(unp->unp_addr, &xu->xu_addr, 1448 unp->unp_addr->sun_len); 1449 if (unp->unp_conn != NULL && 1450 unp->unp_conn->unp_addr != NULL) 1451 bcopy(unp->unp_conn->unp_addr, 1452 &xu->xu_caddr, 1453 unp->unp_conn->unp_addr->sun_len); 1454 bcopy(unp, &xu->xu_unp, sizeof *unp); 1455 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1456 UNP_PCB_UNLOCK(unp); 1457 error = SYSCTL_OUT(req, xu, sizeof *xu); 1458 } else { 1459 freeunp = (unp->unp_refcount == 0); 1460 UNP_PCB_UNLOCK(unp); 1461 if (freeunp) { 1462 UNP_PCB_LOCK_DESTROY(unp); 1463 uma_zfree(unp_zone, unp); 1464 } 1465 } 1466 } 1467 free(xu, M_TEMP); 1468 if (!error) { 1469 /* 1470 * Give the user an updated idea of our state. If the 1471 * generation differs from what we told her before, she knows 1472 * that something happened while we were processing this 1473 * request, and it might be necessary to retry. 1474 */ 1475 xug->xug_gen = unp_gencnt; 1476 xug->xug_sogen = so_gencnt; 1477 xug->xug_count = unp_count; 1478 error = SYSCTL_OUT(req, xug, sizeof *xug); 1479 } 1480 free(unp_list, M_TEMP); 1481 free(xug, M_TEMP); 1482 return (error); 1483 } 1484 1485 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1486 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1487 "List of active local datagram sockets"); 1488 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1489 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1490 "List of active local stream sockets"); 1491 1492 static void 1493 unp_shutdown(struct unpcb *unp) 1494 { 1495 struct unpcb *unp2; 1496 struct socket *so; 1497 1498 UNP_GLOBAL_WLOCK_ASSERT(); 1499 UNP_PCB_LOCK_ASSERT(unp); 1500 1501 unp2 = unp->unp_conn; 1502 if (unp->unp_socket->so_type == SOCK_STREAM && unp2 != NULL) { 1503 so = unp2->unp_socket; 1504 if (so != NULL) 1505 socantrcvmore(so); 1506 } 1507 } 1508 1509 static void 1510 unp_drop(struct unpcb *unp, int errno) 1511 { 1512 struct socket *so = unp->unp_socket; 1513 struct unpcb *unp2; 1514 1515 UNP_GLOBAL_WLOCK_ASSERT(); 1516 UNP_PCB_LOCK_ASSERT(unp); 1517 1518 so->so_error = errno; 1519 unp2 = unp->unp_conn; 1520 if (unp2 == NULL) 1521 return; 1522 UNP_PCB_LOCK(unp2); 1523 unp_disconnect(unp, unp2); 1524 UNP_PCB_UNLOCK(unp2); 1525 } 1526 1527 static void 1528 unp_freerights(struct file **rp, int fdcount) 1529 { 1530 int i; 1531 struct file *fp; 1532 1533 for (i = 0; i < fdcount; i++) { 1534 fp = *rp; 1535 *rp++ = NULL; 1536 unp_discard(fp); 1537 } 1538 } 1539 1540 static int 1541 unp_externalize(struct mbuf *control, struct mbuf **controlp) 1542 { 1543 struct thread *td = curthread; /* XXX */ 1544 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1545 int i; 1546 int *fdp; 1547 struct file **rp; 1548 struct file *fp; 1549 void *data; 1550 socklen_t clen = control->m_len, datalen; 1551 int error, newfds; 1552 int f; 1553 u_int newlen; 1554 1555 UNP_GLOBAL_UNLOCK_ASSERT(); 1556 1557 error = 0; 1558 if (controlp != NULL) /* controlp == NULL => free control messages */ 1559 *controlp = NULL; 1560 while (cm != NULL) { 1561 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1562 error = EINVAL; 1563 break; 1564 } 1565 data = CMSG_DATA(cm); 1566 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1567 if (cm->cmsg_level == SOL_SOCKET 1568 && cm->cmsg_type == SCM_RIGHTS) { 1569 newfds = datalen / sizeof(struct file *); 1570 rp = data; 1571 1572 /* If we're not outputting the descriptors free them. */ 1573 if (error || controlp == NULL) { 1574 unp_freerights(rp, newfds); 1575 goto next; 1576 } 1577 FILEDESC_XLOCK(td->td_proc->p_fd); 1578 /* if the new FD's will not fit free them. */ 1579 if (!fdavail(td, newfds)) { 1580 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1581 error = EMSGSIZE; 1582 unp_freerights(rp, newfds); 1583 goto next; 1584 } 1585 1586 /* 1587 * Now change each pointer to an fd in the global 1588 * table to an integer that is the index to the local 1589 * fd table entry that we set up to point to the 1590 * global one we are transferring. 1591 */ 1592 newlen = newfds * sizeof(int); 1593 *controlp = sbcreatecontrol(NULL, newlen, 1594 SCM_RIGHTS, SOL_SOCKET); 1595 if (*controlp == NULL) { 1596 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1597 error = E2BIG; 1598 unp_freerights(rp, newfds); 1599 goto next; 1600 } 1601 1602 fdp = (int *) 1603 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1604 for (i = 0; i < newfds; i++) { 1605 if (fdalloc(td, 0, &f)) 1606 panic("unp_externalize fdalloc failed"); 1607 fp = *rp++; 1608 td->td_proc->p_fd->fd_ofiles[f] = fp; 1609 FILE_LOCK(fp); 1610 fp->f_msgcount--; 1611 FILE_UNLOCK(fp); 1612 UNP_GLOBAL_WLOCK(); 1613 unp_rights--; 1614 UNP_GLOBAL_WUNLOCK(); 1615 *fdp++ = f; 1616 } 1617 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1618 } else { 1619 /* We can just copy anything else across. */ 1620 if (error || controlp == NULL) 1621 goto next; 1622 *controlp = sbcreatecontrol(NULL, datalen, 1623 cm->cmsg_type, cm->cmsg_level); 1624 if (*controlp == NULL) { 1625 error = ENOBUFS; 1626 goto next; 1627 } 1628 bcopy(data, 1629 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1630 datalen); 1631 } 1632 controlp = &(*controlp)->m_next; 1633 1634 next: 1635 if (CMSG_SPACE(datalen) < clen) { 1636 clen -= CMSG_SPACE(datalen); 1637 cm = (struct cmsghdr *) 1638 ((caddr_t)cm + CMSG_SPACE(datalen)); 1639 } else { 1640 clen = 0; 1641 cm = NULL; 1642 } 1643 } 1644 1645 m_freem(control); 1646 return (error); 1647 } 1648 1649 static void 1650 unp_zone_change(void *tag) 1651 { 1652 1653 uma_zone_set_max(unp_zone, maxsockets); 1654 } 1655 1656 static void 1657 unp_init(void) 1658 { 1659 1660 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1661 NULL, NULL, UMA_ALIGN_PTR, 0); 1662 if (unp_zone == NULL) 1663 panic("unp_init"); 1664 uma_zone_set_max(unp_zone, maxsockets); 1665 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change, 1666 NULL, EVENTHANDLER_PRI_ANY); 1667 LIST_INIT(&unp_dhead); 1668 LIST_INIT(&unp_shead); 1669 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1670 UNP_GLOBAL_LOCK_INIT(); 1671 } 1672 1673 static int 1674 unp_internalize(struct mbuf **controlp, struct thread *td) 1675 { 1676 struct mbuf *control = *controlp; 1677 struct proc *p = td->td_proc; 1678 struct filedesc *fdescp = p->p_fd; 1679 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1680 struct cmsgcred *cmcred; 1681 struct file **rp; 1682 struct file *fp; 1683 struct timeval *tv; 1684 int i, fd, *fdp; 1685 void *data; 1686 socklen_t clen = control->m_len, datalen; 1687 int error, oldfds; 1688 u_int newlen; 1689 1690 UNP_GLOBAL_UNLOCK_ASSERT(); 1691 1692 error = 0; 1693 *controlp = NULL; 1694 while (cm != NULL) { 1695 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1696 || cm->cmsg_len > clen) { 1697 error = EINVAL; 1698 goto out; 1699 } 1700 data = CMSG_DATA(cm); 1701 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1702 1703 switch (cm->cmsg_type) { 1704 /* 1705 * Fill in credential information. 1706 */ 1707 case SCM_CREDS: 1708 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1709 SCM_CREDS, SOL_SOCKET); 1710 if (*controlp == NULL) { 1711 error = ENOBUFS; 1712 goto out; 1713 } 1714 cmcred = (struct cmsgcred *) 1715 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1716 cmcred->cmcred_pid = p->p_pid; 1717 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1718 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1719 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1720 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1721 CMGROUP_MAX); 1722 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1723 cmcred->cmcred_groups[i] = 1724 td->td_ucred->cr_groups[i]; 1725 break; 1726 1727 case SCM_RIGHTS: 1728 oldfds = datalen / sizeof (int); 1729 /* 1730 * Check that all the FDs passed in refer to legal 1731 * files. If not, reject the entire operation. 1732 */ 1733 fdp = data; 1734 FILEDESC_SLOCK(fdescp); 1735 for (i = 0; i < oldfds; i++) { 1736 fd = *fdp++; 1737 if ((unsigned)fd >= fdescp->fd_nfiles || 1738 fdescp->fd_ofiles[fd] == NULL) { 1739 FILEDESC_SUNLOCK(fdescp); 1740 error = EBADF; 1741 goto out; 1742 } 1743 fp = fdescp->fd_ofiles[fd]; 1744 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1745 FILEDESC_SUNLOCK(fdescp); 1746 error = EOPNOTSUPP; 1747 goto out; 1748 } 1749 1750 } 1751 1752 /* 1753 * Now replace the integer FDs with pointers to the 1754 * associated global file table entry.. 1755 */ 1756 newlen = oldfds * sizeof(struct file *); 1757 *controlp = sbcreatecontrol(NULL, newlen, 1758 SCM_RIGHTS, SOL_SOCKET); 1759 if (*controlp == NULL) { 1760 FILEDESC_SUNLOCK(fdescp); 1761 error = E2BIG; 1762 goto out; 1763 } 1764 fdp = data; 1765 rp = (struct file **) 1766 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1767 for (i = 0; i < oldfds; i++) { 1768 fp = fdescp->fd_ofiles[*fdp++]; 1769 *rp++ = fp; 1770 FILE_LOCK(fp); 1771 fp->f_count++; 1772 fp->f_msgcount++; 1773 FILE_UNLOCK(fp); 1774 UNP_GLOBAL_WLOCK(); 1775 unp_rights++; 1776 UNP_GLOBAL_WUNLOCK(); 1777 } 1778 FILEDESC_SUNLOCK(fdescp); 1779 break; 1780 1781 case SCM_TIMESTAMP: 1782 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1783 SCM_TIMESTAMP, SOL_SOCKET); 1784 if (*controlp == NULL) { 1785 error = ENOBUFS; 1786 goto out; 1787 } 1788 tv = (struct timeval *) 1789 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1790 microtime(tv); 1791 break; 1792 1793 default: 1794 error = EINVAL; 1795 goto out; 1796 } 1797 1798 controlp = &(*controlp)->m_next; 1799 if (CMSG_SPACE(datalen) < clen) { 1800 clen -= CMSG_SPACE(datalen); 1801 cm = (struct cmsghdr *) 1802 ((caddr_t)cm + CMSG_SPACE(datalen)); 1803 } else { 1804 clen = 0; 1805 cm = NULL; 1806 } 1807 } 1808 1809 out: 1810 m_freem(control); 1811 return (error); 1812 } 1813 1814 static struct mbuf * 1815 unp_addsockcred(struct thread *td, struct mbuf *control) 1816 { 1817 struct mbuf *m, *n, *n_prev; 1818 struct sockcred *sc; 1819 const struct cmsghdr *cm; 1820 int ngroups; 1821 int i; 1822 1823 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); 1824 m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET); 1825 if (m == NULL) 1826 return (control); 1827 1828 sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *)); 1829 sc->sc_uid = td->td_ucred->cr_ruid; 1830 sc->sc_euid = td->td_ucred->cr_uid; 1831 sc->sc_gid = td->td_ucred->cr_rgid; 1832 sc->sc_egid = td->td_ucred->cr_gid; 1833 sc->sc_ngroups = ngroups; 1834 for (i = 0; i < sc->sc_ngroups; i++) 1835 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 1836 1837 /* 1838 * Unlink SCM_CREDS control messages (struct cmsgcred), since just 1839 * created SCM_CREDS control message (struct sockcred) has another 1840 * format. 1841 */ 1842 if (control != NULL) 1843 for (n = control, n_prev = NULL; n != NULL;) { 1844 cm = mtod(n, struct cmsghdr *); 1845 if (cm->cmsg_level == SOL_SOCKET && 1846 cm->cmsg_type == SCM_CREDS) { 1847 if (n_prev == NULL) 1848 control = n->m_next; 1849 else 1850 n_prev->m_next = n->m_next; 1851 n = m_free(n); 1852 } else { 1853 n_prev = n; 1854 n = n->m_next; 1855 } 1856 } 1857 1858 /* Prepend it to the head. */ 1859 m->m_next = control; 1860 return (m); 1861 } 1862 1863 /* 1864 * unp_defer indicates whether additional work has been defered for a future 1865 * pass through unp_gc(). It is thread local and does not require explicit 1866 * synchronization. 1867 */ 1868 static int unp_defer; 1869 1870 static int unp_taskcount; 1871 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, ""); 1872 1873 static int unp_recycled; 1874 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, ""); 1875 1876 static void 1877 unp_gc(__unused void *arg, int pending) 1878 { 1879 struct file *fp, *nextfp; 1880 struct socket *so; 1881 struct socket *soa; 1882 struct file **extra_ref, **fpp; 1883 int nunref, i; 1884 int nfiles_snap; 1885 int nfiles_slack = 20; 1886 1887 unp_taskcount++; 1888 unp_defer = 0; 1889 1890 /* 1891 * Before going through all this, set all FDs to be NOT deferred and 1892 * NOT externally accessible. 1893 */ 1894 sx_slock(&filelist_lock); 1895 LIST_FOREACH(fp, &filehead, f_list) 1896 fp->f_gcflag &= ~(FMARK|FDEFER); 1897 do { 1898 KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer)); 1899 LIST_FOREACH(fp, &filehead, f_list) { 1900 FILE_LOCK(fp); 1901 /* 1902 * If the file is not open, skip it -- could be a 1903 * file in the process of being opened, or in the 1904 * process of being closed. If the file is 1905 * "closing", it may have been marked for deferred 1906 * consideration. Clear the flag now if so. 1907 */ 1908 if (fp->f_count == 0) { 1909 if (fp->f_gcflag & FDEFER) 1910 unp_defer--; 1911 fp->f_gcflag &= ~(FMARK|FDEFER); 1912 FILE_UNLOCK(fp); 1913 continue; 1914 } 1915 1916 /* 1917 * If we already marked it as 'defer' in a 1918 * previous pass, then try to process it this 1919 * time and un-mark it. 1920 */ 1921 if (fp->f_gcflag & FDEFER) { 1922 fp->f_gcflag &= ~FDEFER; 1923 unp_defer--; 1924 } else { 1925 /* 1926 * If it's not deferred, then check if it's 1927 * already marked.. if so skip it 1928 */ 1929 if (fp->f_gcflag & FMARK) { 1930 FILE_UNLOCK(fp); 1931 continue; 1932 } 1933 1934 /* 1935 * If all references are from messages in 1936 * transit, then skip it. it's not externally 1937 * accessible. 1938 */ 1939 if (fp->f_count == fp->f_msgcount) { 1940 FILE_UNLOCK(fp); 1941 continue; 1942 } 1943 1944 /* 1945 * If it got this far then it must be 1946 * externally accessible. 1947 */ 1948 fp->f_gcflag |= FMARK; 1949 } 1950 1951 /* 1952 * Either it was deferred, or it is externally 1953 * accessible and not already marked so. Now check 1954 * if it is possibly one of OUR sockets. 1955 */ 1956 if (fp->f_type != DTYPE_SOCKET || 1957 (so = fp->f_data) == NULL) { 1958 FILE_UNLOCK(fp); 1959 continue; 1960 } 1961 1962 if (so->so_proto->pr_domain != &localdomain || 1963 (so->so_proto->pr_flags & PR_RIGHTS) == 0) { 1964 FILE_UNLOCK(fp); 1965 continue; 1966 } 1967 1968 /* 1969 * Tell any other threads that do a subsequent 1970 * fdrop() that we are scanning the message 1971 * buffers. 1972 */ 1973 fp->f_gcflag |= FWAIT; 1974 FILE_UNLOCK(fp); 1975 1976 /* 1977 * So, Ok, it's one of our sockets and it IS 1978 * externally accessible (or was deferred). Now we 1979 * look to see if we hold any file descriptors in its 1980 * message buffers. Follow those links and mark them 1981 * as accessible too. 1982 */ 1983 SOCKBUF_LOCK(&so->so_rcv); 1984 unp_scan(so->so_rcv.sb_mb, unp_mark); 1985 SOCKBUF_UNLOCK(&so->so_rcv); 1986 1987 /* 1988 * If socket is in listening state, then sockets 1989 * in its accept queue are accessible, and so 1990 * are any descriptors in those sockets' receive 1991 * queues. 1992 */ 1993 ACCEPT_LOCK(); 1994 TAILQ_FOREACH(soa, &so->so_comp, so_list) { 1995 SOCKBUF_LOCK(&soa->so_rcv); 1996 unp_scan(soa->so_rcv.sb_mb, unp_mark); 1997 SOCKBUF_UNLOCK(&soa->so_rcv); 1998 } 1999 ACCEPT_UNLOCK(); 2000 2001 /* 2002 * Wake up any threads waiting in fdrop(). 2003 */ 2004 FILE_LOCK(fp); 2005 fp->f_gcflag &= ~FWAIT; 2006 wakeup(&fp->f_gcflag); 2007 FILE_UNLOCK(fp); 2008 } 2009 } while (unp_defer); 2010 sx_sunlock(&filelist_lock); 2011 2012 /* 2013 * XXXRW: The following comments need updating for a post-SMPng and 2014 * deferred unp_gc() world, but are still generally accurate. 2015 * 2016 * We grab an extra reference to each of the file table entries that 2017 * are not otherwise accessible and then free the rights that are 2018 * stored in messages on them. 2019 * 2020 * The bug in the orginal code is a little tricky, so I'll describe 2021 * what's wrong with it here. 2022 * 2023 * It is incorrect to simply unp_discard each entry for f_msgcount 2024 * times -- consider the case of sockets A and B that contain 2025 * references to each other. On a last close of some other socket, 2026 * we trigger a gc since the number of outstanding rights (unp_rights) 2027 * is non-zero. If during the sweep phase the gc code unp_discards, 2028 * we end up doing a (full) closef on the descriptor. A closef on A 2029 * results in the following chain. Closef calls soo_close, which 2030 * calls soclose. Soclose calls first (through the switch 2031 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 2032 * returns because the previous instance had set unp_gcing, and we 2033 * return all the way back to soclose, which marks the socket with 2034 * SS_NOFDREF, and then calls sofree. Sofree calls sorflush to free 2035 * up the rights that are queued in messages on the socket A, i.e., 2036 * the reference on B. The sorflush calls via the dom_dispose switch 2037 * unp_dispose, which unp_scans with unp_discard. This second 2038 * instance of unp_discard just calls closef on B. 2039 * 2040 * Well, a similar chain occurs on B, resulting in a sorflush on B, 2041 * which results in another closef on A. Unfortunately, A is already 2042 * being closed, and the descriptor has already been marked with 2043 * SS_NOFDREF, and soclose panics at this point. 2044 * 2045 * Here, we first take an extra reference to each inaccessible 2046 * descriptor. Then, we call sorflush ourself, since we know it is a 2047 * Unix domain socket anyhow. After we destroy all the rights 2048 * carried in messages, we do a last closef to get rid of our extra 2049 * reference. This is the last close, and the unp_detach etc will 2050 * shut down the socket. 2051 * 2052 * 91/09/19, bsy@cs.cmu.edu 2053 */ 2054 again: 2055 nfiles_snap = openfiles + nfiles_slack; /* some slack */ 2056 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 2057 M_WAITOK); 2058 sx_slock(&filelist_lock); 2059 if (nfiles_snap < openfiles) { 2060 sx_sunlock(&filelist_lock); 2061 free(extra_ref, M_TEMP); 2062 nfiles_slack += 20; 2063 goto again; 2064 } 2065 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 2066 fp != NULL; fp = nextfp) { 2067 nextfp = LIST_NEXT(fp, f_list); 2068 FILE_LOCK(fp); 2069 2070 /* 2071 * If it's not open, skip it 2072 */ 2073 if (fp->f_count == 0) { 2074 FILE_UNLOCK(fp); 2075 continue; 2076 } 2077 2078 /* 2079 * If all refs are from msgs, and it's not marked accessible 2080 * then it must be referenced from some unreachable cycle of 2081 * (shut-down) FDs, so include it in our list of FDs to 2082 * remove. 2083 */ 2084 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 2085 *fpp++ = fp; 2086 nunref++; 2087 fp->f_count++; 2088 } 2089 FILE_UNLOCK(fp); 2090 } 2091 sx_sunlock(&filelist_lock); 2092 2093 /* 2094 * For each FD on our hit list, do the following two things: 2095 */ 2096 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2097 struct file *tfp = *fpp; 2098 FILE_LOCK(tfp); 2099 if (tfp->f_type == DTYPE_SOCKET && 2100 tfp->f_data != NULL) { 2101 FILE_UNLOCK(tfp); 2102 sorflush(tfp->f_data); 2103 } else { 2104 FILE_UNLOCK(tfp); 2105 } 2106 } 2107 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 2108 closef(*fpp, (struct thread *) NULL); 2109 unp_recycled++; 2110 } 2111 free(extra_ref, M_TEMP); 2112 } 2113 2114 static void 2115 unp_dispose(struct mbuf *m) 2116 { 2117 2118 if (m) 2119 unp_scan(m, unp_discard); 2120 } 2121 2122 static void 2123 unp_scan(struct mbuf *m0, void (*op)(struct file *)) 2124 { 2125 struct mbuf *m; 2126 struct file **rp; 2127 struct cmsghdr *cm; 2128 void *data; 2129 int i; 2130 socklen_t clen, datalen; 2131 int qfds; 2132 2133 while (m0 != NULL) { 2134 for (m = m0; m; m = m->m_next) { 2135 if (m->m_type != MT_CONTROL) 2136 continue; 2137 2138 cm = mtod(m, struct cmsghdr *); 2139 clen = m->m_len; 2140 2141 while (cm != NULL) { 2142 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 2143 break; 2144 2145 data = CMSG_DATA(cm); 2146 datalen = (caddr_t)cm + cm->cmsg_len 2147 - (caddr_t)data; 2148 2149 if (cm->cmsg_level == SOL_SOCKET && 2150 cm->cmsg_type == SCM_RIGHTS) { 2151 qfds = datalen / sizeof (struct file *); 2152 rp = data; 2153 for (i = 0; i < qfds; i++) 2154 (*op)(*rp++); 2155 } 2156 2157 if (CMSG_SPACE(datalen) < clen) { 2158 clen -= CMSG_SPACE(datalen); 2159 cm = (struct cmsghdr *) 2160 ((caddr_t)cm + CMSG_SPACE(datalen)); 2161 } else { 2162 clen = 0; 2163 cm = NULL; 2164 } 2165 } 2166 } 2167 m0 = m0->m_act; 2168 } 2169 } 2170 2171 static void 2172 unp_mark(struct file *fp) 2173 { 2174 2175 /* XXXRW: Should probably assert file list lock here. */ 2176 2177 if (fp->f_gcflag & FMARK) 2178 return; 2179 unp_defer++; 2180 fp->f_gcflag |= (FMARK|FDEFER); 2181 } 2182 2183 static void 2184 unp_discard(struct file *fp) 2185 { 2186 2187 UNP_GLOBAL_WLOCK(); 2188 FILE_LOCK(fp); 2189 fp->f_msgcount--; 2190 unp_rights--; 2191 FILE_UNLOCK(fp); 2192 UNP_GLOBAL_WUNLOCK(); 2193 (void) closef(fp, (struct thread *)NULL); 2194 } 2195 2196 #ifdef DDB 2197 static void 2198 db_print_indent(int indent) 2199 { 2200 int i; 2201 2202 for (i = 0; i < indent; i++) 2203 db_printf(" "); 2204 } 2205 2206 static void 2207 db_print_unpflags(int unp_flags) 2208 { 2209 int comma; 2210 2211 comma = 0; 2212 if (unp_flags & UNP_HAVEPC) { 2213 db_printf("%sUNP_HAVEPC", comma ? ", " : ""); 2214 comma = 1; 2215 } 2216 if (unp_flags & UNP_HAVEPCCACHED) { 2217 db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : ""); 2218 comma = 1; 2219 } 2220 if (unp_flags & UNP_WANTCRED) { 2221 db_printf("%sUNP_WANTCRED", comma ? ", " : ""); 2222 comma = 1; 2223 } 2224 if (unp_flags & UNP_CONNWAIT) { 2225 db_printf("%sUNP_CONNWAIT", comma ? ", " : ""); 2226 comma = 1; 2227 } 2228 if (unp_flags & UNP_CONNECTING) { 2229 db_printf("%sUNP_CONNECTING", comma ? ", " : ""); 2230 comma = 1; 2231 } 2232 if (unp_flags & UNP_BINDING) { 2233 db_printf("%sUNP_BINDING", comma ? ", " : ""); 2234 comma = 1; 2235 } 2236 } 2237 2238 static void 2239 db_print_xucred(int indent, struct xucred *xu) 2240 { 2241 int comma, i; 2242 2243 db_print_indent(indent); 2244 db_printf("cr_version: %u cr_uid: %u cr_ngroups: %d\n", 2245 xu->cr_version, xu->cr_uid, xu->cr_ngroups); 2246 db_print_indent(indent); 2247 db_printf("cr_groups: "); 2248 comma = 0; 2249 for (i = 0; i < xu->cr_ngroups; i++) { 2250 db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]); 2251 comma = 1; 2252 } 2253 db_printf("\n"); 2254 } 2255 2256 static void 2257 db_print_unprefs(int indent, struct unp_head *uh) 2258 { 2259 struct unpcb *unp; 2260 int counter; 2261 2262 counter = 0; 2263 LIST_FOREACH(unp, uh, unp_reflink) { 2264 if (counter % 4 == 0) 2265 db_print_indent(indent); 2266 db_printf("%p ", unp); 2267 if (counter % 4 == 3) 2268 db_printf("\n"); 2269 counter++; 2270 } 2271 if (counter != 0 && counter % 4 != 0) 2272 db_printf("\n"); 2273 } 2274 2275 DB_SHOW_COMMAND(unpcb, db_show_unpcb) 2276 { 2277 struct unpcb *unp; 2278 2279 if (!have_addr) { 2280 db_printf("usage: show unpcb <addr>\n"); 2281 return; 2282 } 2283 unp = (struct unpcb *)addr; 2284 2285 db_printf("unp_socket: %p unp_vnode: %p\n", unp->unp_socket, 2286 unp->unp_vnode); 2287 2288 db_printf("unp_ino: %d unp_conn: %p\n", unp->unp_ino, 2289 unp->unp_conn); 2290 2291 db_printf("unp_refs:\n"); 2292 db_print_unprefs(2, &unp->unp_refs); 2293 2294 /* XXXRW: Would be nice to print the full address, if any. */ 2295 db_printf("unp_addr: %p\n", unp->unp_addr); 2296 2297 db_printf("unp_cc: %d unp_mbcnt: %d unp_gencnt: %llu\n", 2298 unp->unp_cc, unp->unp_mbcnt, 2299 (unsigned long long)unp->unp_gencnt); 2300 2301 db_printf("unp_flags: %x (", unp->unp_flags); 2302 db_print_unpflags(unp->unp_flags); 2303 db_printf(")\n"); 2304 2305 db_printf("unp_peercred:\n"); 2306 db_print_xucred(2, &unp->unp_peercred); 2307 2308 db_printf("unp_refcount: %u\n", unp->unp_refcount); 2309 } 2310 #endif
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