lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1998-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <assert.h> |
| 20 | #include <errno.h> |
| 21 | #include <fcntl.h> |
| 22 | #include <stdbool.h> |
| 23 | #include <stddef.h> |
| 24 | #include <stdlib.h> |
| 25 | #include <string.h> |
| 26 | #include <time.h> |
| 27 | #include <unistd.h> |
| 28 | #include <stdint.h> |
| 29 | #include <sys/mman.h> |
| 30 | #include <sys/poll.h> |
| 31 | #include <sys/socket.h> |
| 32 | #include <sys/stat.h> |
| 33 | #include <sys/time.h> |
| 34 | #include <sys/uio.h> |
| 35 | #include <sys/un.h> |
| 36 | #include <not-cancel.h> |
| 37 | #include <nis/rpcsvc/nis.h> |
| 38 | #include <kernel-features.h> |
| 39 | |
| 40 | #include "nscd-client.h" |
| 41 | |
| 42 | |
| 43 | /* Extra time we wait if the socket is still receiving data. This |
| 44 | value is in milliseconds. Note that the other side is nscd on the |
| 45 | local machine and it is already transmitting data. So the wait |
| 46 | time need not be long. */ |
| 47 | #define EXTRA_RECEIVE_TIME 200 |
| 48 | |
| 49 | |
| 50 | static int |
| 51 | wait_on_socket (int sock, long int usectmo) |
| 52 | { |
| 53 | struct pollfd fds[1]; |
| 54 | fds[0].fd = sock; |
| 55 | fds[0].events = POLLIN | POLLERR | POLLHUP; |
| 56 | int n = __poll (fds, 1, usectmo); |
| 57 | if (n == -1 && __builtin_expect (errno == EINTR, 0)) |
| 58 | { |
| 59 | /* Handle the case where the poll() call is interrupted by a |
| 60 | signal. We cannot just use TEMP_FAILURE_RETRY since it might |
| 61 | lead to infinite loops. */ |
| 62 | struct timeval now; |
| 63 | (void) __gettimeofday (&now, NULL); |
| 64 | long int end = now.tv_sec * 1000 + usectmo + (now.tv_usec + 500) / 1000; |
| 65 | long int timeout = usectmo; |
| 66 | while (1) |
| 67 | { |
| 68 | n = __poll (fds, 1, timeout); |
| 69 | if (n != -1 || errno != EINTR) |
| 70 | break; |
| 71 | |
| 72 | /* Recompute the timeout time. */ |
| 73 | (void) __gettimeofday (&now, NULL); |
| 74 | timeout = end - (now.tv_sec * 1000 + (now.tv_usec + 500) / 1000); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | return n; |
| 79 | } |
| 80 | |
| 81 | |
| 82 | ssize_t |
| 83 | __readall (int fd, void *buf, size_t len) |
| 84 | { |
| 85 | size_t n = len; |
| 86 | ssize_t ret; |
| 87 | do |
| 88 | { |
| 89 | again: |
| 90 | ret = TEMP_FAILURE_RETRY (__read (fd, buf, n)); |
| 91 | if (ret <= 0) |
| 92 | { |
| 93 | if (__builtin_expect (ret < 0 && errno == EAGAIN, 0) |
| 94 | /* The socket is still receiving data. Wait a bit more. */ |
| 95 | && wait_on_socket (fd, EXTRA_RECEIVE_TIME) > 0) |
| 96 | goto again; |
| 97 | |
| 98 | break; |
| 99 | } |
| 100 | buf = (char *) buf + ret; |
| 101 | n -= ret; |
| 102 | } |
| 103 | while (n > 0); |
| 104 | return ret < 0 ? ret : len - n; |
| 105 | } |
| 106 | |
| 107 | |
| 108 | ssize_t |
| 109 | __readvall (int fd, const struct iovec *iov, int iovcnt) |
| 110 | { |
| 111 | ssize_t ret = TEMP_FAILURE_RETRY (__readv (fd, iov, iovcnt)); |
| 112 | if (ret <= 0) |
| 113 | { |
| 114 | if (__glibc_likely (ret == 0 || errno != EAGAIN)) |
| 115 | /* A genuine error or no data to read. */ |
| 116 | return ret; |
| 117 | |
| 118 | /* The data has not all yet been received. Do as if we have not |
| 119 | read anything yet. */ |
| 120 | ret = 0; |
| 121 | } |
| 122 | |
| 123 | size_t total = 0; |
| 124 | for (int i = 0; i < iovcnt; ++i) |
| 125 | total += iov[i].iov_len; |
| 126 | |
| 127 | if (ret < total) |
| 128 | { |
| 129 | struct iovec iov_buf[iovcnt]; |
| 130 | ssize_t r = ret; |
| 131 | |
| 132 | struct iovec *iovp = memcpy (iov_buf, iov, iovcnt * sizeof (*iov)); |
| 133 | do |
| 134 | { |
| 135 | while (iovp->iov_len <= r) |
| 136 | { |
| 137 | r -= iovp->iov_len; |
| 138 | --iovcnt; |
| 139 | ++iovp; |
| 140 | } |
| 141 | iovp->iov_base = (char *) iovp->iov_base + r; |
| 142 | iovp->iov_len -= r; |
| 143 | again: |
| 144 | r = TEMP_FAILURE_RETRY (__readv (fd, iovp, iovcnt)); |
| 145 | if (r <= 0) |
| 146 | { |
| 147 | if (__builtin_expect (r < 0 && errno == EAGAIN, 0) |
| 148 | /* The socket is still receiving data. Wait a bit more. */ |
| 149 | && wait_on_socket (fd, EXTRA_RECEIVE_TIME) > 0) |
| 150 | goto again; |
| 151 | |
| 152 | break; |
| 153 | } |
| 154 | ret += r; |
| 155 | } |
| 156 | while (ret < total); |
| 157 | if (r < 0) |
| 158 | ret = r; |
| 159 | } |
| 160 | return ret; |
| 161 | } |
| 162 | |
| 163 | |
| 164 | static int |
| 165 | open_socket (request_type type, const char *key, size_t keylen) |
| 166 | { |
| 167 | int sock; |
| 168 | |
| 169 | #ifdef SOCK_CLOEXEC |
| 170 | # ifndef __ASSUME_SOCK_CLOEXEC |
| 171 | if (__have_sock_cloexec >= 0) |
| 172 | # endif |
| 173 | { |
| 174 | sock = __socket (PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); |
| 175 | # ifndef __ASSUME_SOCK_CLOEXEC |
| 176 | if (__have_sock_cloexec == 0) |
| 177 | __have_sock_cloexec = sock != -1 || errno != EINVAL ? 1 : -1; |
| 178 | # endif |
| 179 | } |
| 180 | #endif |
| 181 | #ifndef __ASSUME_SOCK_CLOEXEC |
| 182 | # ifdef SOCK_CLOEXEC |
| 183 | if (__have_sock_cloexec < 0) |
| 184 | # endif |
| 185 | sock = __socket (PF_UNIX, SOCK_STREAM, 0); |
| 186 | #endif |
| 187 | if (sock < 0) |
| 188 | return -1; |
| 189 | |
| 190 | size_t real_sizeof_reqdata = sizeof (request_header) + keylen; |
| 191 | struct |
| 192 | { |
| 193 | request_header req; |
| 194 | char key[]; |
| 195 | } *reqdata = alloca (real_sizeof_reqdata); |
| 196 | |
| 197 | #ifndef __ASSUME_SOCK_CLOEXEC |
| 198 | # ifdef SOCK_NONBLOCK |
| 199 | if (__have_sock_cloexec < 0) |
| 200 | # endif |
| 201 | /* Make socket non-blocking. */ |
| 202 | __fcntl (sock, F_SETFL, O_RDWR | O_NONBLOCK); |
| 203 | #endif |
| 204 | |
| 205 | struct sockaddr_un sun; |
| 206 | sun.sun_family = AF_UNIX; |
| 207 | strcpy (sun.sun_path, _PATH_NSCDSOCKET); |
| 208 | if (__connect (sock, (struct sockaddr *) &sun, sizeof (sun)) < 0 |
| 209 | && errno != EINPROGRESS) |
| 210 | goto out; |
| 211 | |
| 212 | reqdata->req.version = NSCD_VERSION; |
| 213 | reqdata->req.type = type; |
| 214 | reqdata->req.key_len = keylen; |
| 215 | |
| 216 | memcpy (reqdata->key, key, keylen); |
| 217 | |
| 218 | bool first_try = true; |
| 219 | struct timeval tvend; |
| 220 | /* Fake initializing tvend. */ |
| 221 | asm ("" : "=m" (tvend)); |
| 222 | while (1) |
| 223 | { |
| 224 | #ifndef MSG_NOSIGNAL |
| 225 | # define MSG_NOSIGNAL 0 |
| 226 | #endif |
| 227 | ssize_t wres = TEMP_FAILURE_RETRY (__send (sock, reqdata, |
| 228 | real_sizeof_reqdata, |
| 229 | MSG_NOSIGNAL)); |
| 230 | if (__glibc_likely (wres == (ssize_t) real_sizeof_reqdata)) |
| 231 | /* We managed to send the request. */ |
| 232 | return sock; |
| 233 | |
| 234 | if (wres != -1 || errno != EAGAIN) |
| 235 | /* Something is really wrong, no chance to continue. */ |
| 236 | break; |
| 237 | |
| 238 | /* The daemon is busy wait for it. */ |
| 239 | int to; |
| 240 | struct timeval now; |
| 241 | (void) __gettimeofday (&now, NULL); |
| 242 | if (first_try) |
| 243 | { |
| 244 | tvend.tv_usec = now.tv_usec; |
| 245 | tvend.tv_sec = now.tv_sec + 5; |
| 246 | to = 5 * 1000; |
| 247 | first_try = false; |
| 248 | } |
| 249 | else |
| 250 | to = ((tvend.tv_sec - now.tv_sec) * 1000 |
| 251 | + (tvend.tv_usec - now.tv_usec) / 1000); |
| 252 | |
| 253 | struct pollfd fds[1]; |
| 254 | fds[0].fd = sock; |
| 255 | fds[0].events = POLLOUT | POLLERR | POLLHUP; |
| 256 | if (__poll (fds, 1, to) <= 0) |
| 257 | /* The connection timed out or broke down. */ |
| 258 | break; |
| 259 | |
| 260 | /* We try to write again. */ |
| 261 | } |
| 262 | |
| 263 | out: |
| 264 | close_not_cancel_no_status (sock); |
| 265 | |
| 266 | return -1; |
| 267 | } |
| 268 | |
| 269 | |
| 270 | void |
| 271 | __nscd_unmap (struct mapped_database *mapped) |
| 272 | { |
| 273 | assert (mapped->counter == 0); |
| 274 | __munmap ((void *) mapped->head, mapped->mapsize); |
| 275 | free (mapped); |
| 276 | } |
| 277 | |
| 278 | |
| 279 | /* Try to get a file descriptor for the shared meory segment |
| 280 | containing the database. */ |
| 281 | struct mapped_database * |
| 282 | __nscd_get_mapping (request_type type, const char *key, |
| 283 | struct mapped_database **mappedp) |
| 284 | { |
| 285 | struct mapped_database *result = NO_MAPPING; |
| 286 | #ifdef SCM_RIGHTS |
| 287 | const size_t keylen = strlen (key) + 1; |
| 288 | int saved_errno = errno; |
| 289 | |
| 290 | int mapfd = -1; |
| 291 | char resdata[keylen]; |
| 292 | |
| 293 | /* Open a socket and send the request. */ |
| 294 | int sock = open_socket (type, key, keylen); |
| 295 | if (sock < 0) |
| 296 | goto out; |
| 297 | |
| 298 | /* Room for the data sent along with the file descriptor. We expect |
| 299 | the key name back. */ |
| 300 | uint64_t mapsize; |
| 301 | struct iovec iov[2]; |
| 302 | iov[0].iov_base = resdata; |
| 303 | iov[0].iov_len = keylen; |
| 304 | iov[1].iov_base = &mapsize; |
| 305 | iov[1].iov_len = sizeof (mapsize); |
| 306 | |
| 307 | union |
| 308 | { |
| 309 | struct cmsghdr hdr; |
| 310 | char bytes[CMSG_SPACE (sizeof (int))]; |
| 311 | } buf; |
| 312 | struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 2, |
| 313 | .msg_control = buf.bytes, |
| 314 | .msg_controllen = sizeof (buf) }; |
| 315 | struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg); |
| 316 | |
| 317 | cmsg->cmsg_level = SOL_SOCKET; |
| 318 | cmsg->cmsg_type = SCM_RIGHTS; |
| 319 | cmsg->cmsg_len = CMSG_LEN (sizeof (int)); |
| 320 | |
| 321 | /* This access is well-aligned since BUF is correctly aligned for an |
| 322 | int and CMSG_DATA preserves this alignment. */ |
| 323 | memset (CMSG_DATA (cmsg), '\xff', sizeof (int)); |
| 324 | |
| 325 | msg.msg_controllen = cmsg->cmsg_len; |
| 326 | |
| 327 | if (wait_on_socket (sock, 5 * 1000) <= 0) |
| 328 | goto out_close2; |
| 329 | |
| 330 | # ifndef MSG_CMSG_CLOEXEC |
| 331 | # define MSG_CMSG_CLOEXEC 0 |
| 332 | # endif |
| 333 | ssize_t n = TEMP_FAILURE_RETRY (__recvmsg (sock, &msg, MSG_CMSG_CLOEXEC)); |
| 334 | |
| 335 | if (__builtin_expect (CMSG_FIRSTHDR (&msg) == NULL |
| 336 | || (CMSG_FIRSTHDR (&msg)->cmsg_len |
| 337 | != CMSG_LEN (sizeof (int))), 0)) |
| 338 | goto out_close2; |
| 339 | |
| 340 | int *ip = (void *) CMSG_DATA (cmsg); |
| 341 | mapfd = *ip; |
| 342 | |
| 343 | if (__glibc_unlikely (n != keylen && n != keylen + sizeof (mapsize))) |
| 344 | goto out_close; |
| 345 | |
| 346 | if (__glibc_unlikely (strcmp (resdata, key) != 0)) |
| 347 | goto out_close; |
| 348 | |
| 349 | if (__glibc_unlikely (n == keylen)) |
| 350 | { |
| 351 | struct stat64 st; |
| 352 | if (__builtin_expect (fstat64 (mapfd, &st) != 0, 0) |
| 353 | || __builtin_expect (st.st_size < sizeof (struct database_pers_head), |
| 354 | 0)) |
| 355 | goto out_close; |
| 356 | |
| 357 | mapsize = st.st_size; |
| 358 | } |
| 359 | |
| 360 | /* The file is large enough, map it now. */ |
| 361 | void *mapping = __mmap (NULL, mapsize, PROT_READ, MAP_SHARED, mapfd, 0); |
| 362 | if (__glibc_likely (mapping != MAP_FAILED)) |
| 363 | { |
| 364 | /* Check whether the database is correct and up-to-date. */ |
| 365 | struct database_pers_head *head = mapping; |
| 366 | |
| 367 | if (__builtin_expect (head->version != DB_VERSION, 0) |
| 368 | || __builtin_expect (head->header_size != sizeof (*head), 0) |
| 369 | /* Catch some misconfiguration. The server should catch |
| 370 | them now but some older versions did not. */ |
| 371 | || __builtin_expect (head->module == 0, 0) |
| 372 | /* This really should not happen but who knows, maybe the update |
| 373 | thread got stuck. */ |
| 374 | || __builtin_expect (! head->nscd_certainly_running |
| 375 | && (head->timestamp + MAPPING_TIMEOUT |
| 376 | < time (NULL)), 0)) |
| 377 | { |
| 378 | out_unmap: |
| 379 | __munmap (mapping, mapsize); |
| 380 | goto out_close; |
| 381 | } |
| 382 | |
| 383 | size_t size = (sizeof (*head) + roundup (head->module * sizeof (ref_t), |
| 384 | ALIGN) |
| 385 | + head->data_size); |
| 386 | |
| 387 | if (__glibc_unlikely (mapsize < size)) |
| 388 | goto out_unmap; |
| 389 | |
| 390 | /* Allocate a record for the mapping. */ |
| 391 | struct mapped_database *newp = malloc (sizeof (*newp)); |
| 392 | if (newp == NULL) |
| 393 | /* Ugh, after all we went through the memory allocation failed. */ |
| 394 | goto out_unmap; |
| 395 | |
| 396 | newp->head = mapping; |
| 397 | newp->data = ((char *) mapping + head->header_size |
| 398 | + roundup (head->module * sizeof (ref_t), ALIGN)); |
| 399 | newp->mapsize = size; |
| 400 | newp->datasize = head->data_size; |
| 401 | /* Set counter to 1 to show it is usable. */ |
| 402 | newp->counter = 1; |
| 403 | |
| 404 | result = newp; |
| 405 | } |
| 406 | |
| 407 | out_close: |
| 408 | __close (mapfd); |
| 409 | out_close2: |
| 410 | __close (sock); |
| 411 | out: |
| 412 | __set_errno (saved_errno); |
| 413 | #endif /* SCM_RIGHTS */ |
| 414 | |
| 415 | struct mapped_database *oldval = *mappedp; |
| 416 | *mappedp = result; |
| 417 | |
| 418 | if (oldval != NULL && atomic_decrement_val (&oldval->counter) == 0) |
| 419 | __nscd_unmap (oldval); |
| 420 | |
| 421 | return result; |
| 422 | } |
| 423 | |
| 424 | struct mapped_database * |
| 425 | __nscd_get_map_ref (request_type type, const char *name, |
| 426 | volatile struct locked_map_ptr *mapptr, int *gc_cyclep) |
| 427 | { |
| 428 | struct mapped_database *cur = mapptr->mapped; |
| 429 | if (cur == NO_MAPPING) |
| 430 | return cur; |
| 431 | |
| 432 | if (!__nscd_acquire_maplock (mapptr)) |
| 433 | return NO_MAPPING; |
| 434 | |
| 435 | cur = mapptr->mapped; |
| 436 | |
| 437 | if (__glibc_likely (cur != NO_MAPPING)) |
| 438 | { |
| 439 | /* If not mapped or timestamp not updated, request new map. */ |
| 440 | if (cur == NULL |
| 441 | || (cur->head->nscd_certainly_running == 0 |
| 442 | && cur->head->timestamp + MAPPING_TIMEOUT < time (NULL)) |
| 443 | || cur->head->data_size > cur->datasize) |
| 444 | cur = __nscd_get_mapping (type, name, |
| 445 | (struct mapped_database **) &mapptr->mapped); |
| 446 | |
| 447 | if (__glibc_likely (cur != NO_MAPPING)) |
| 448 | { |
| 449 | if (__builtin_expect (((*gc_cyclep = cur->head->gc_cycle) & 1) != 0, |
| 450 | 0)) |
| 451 | cur = NO_MAPPING; |
| 452 | else |
| 453 | atomic_increment (&cur->counter); |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | mapptr->lock = 0; |
| 458 | |
| 459 | return cur; |
| 460 | } |
| 461 | |
| 462 | |
| 463 | /* Using sizeof (hashentry) is not always correct to determine the size of |
| 464 | the data structure as found in the nscd cache. The program could be |
| 465 | a 64-bit process and nscd could be a 32-bit process. In this case |
| 466 | sizeof (hashentry) would overestimate the size. The following is |
| 467 | the minimum size of such an entry, good enough for our tests here. */ |
| 468 | #define MINIMUM_HASHENTRY_SIZE \ |
| 469 | (offsetof (struct hashentry, dellist) + sizeof (int32_t)) |
| 470 | |
| 471 | |
| 472 | /* Don't return const struct datahead *, as eventhough the record |
| 473 | is normally constant, it can change arbitrarily during nscd |
| 474 | garbage collection. */ |
| 475 | struct datahead * |
| 476 | __nscd_cache_search (request_type type, const char *key, size_t keylen, |
| 477 | const struct mapped_database *mapped, size_t datalen) |
| 478 | { |
| 479 | unsigned long int hash = __nis_hash (key, keylen) % mapped->head->module; |
| 480 | size_t datasize = mapped->datasize; |
| 481 | |
| 482 | ref_t trail = mapped->head->array[hash]; |
| 483 | trail = atomic_forced_read (trail); |
| 484 | ref_t work = trail; |
| 485 | size_t loop_cnt = datasize / (MINIMUM_HASHENTRY_SIZE |
| 486 | + offsetof (struct datahead, data) / 2); |
| 487 | int tick = 0; |
| 488 | |
| 489 | while (work != ENDREF && work + MINIMUM_HASHENTRY_SIZE <= datasize) |
| 490 | { |
| 491 | struct hashentry *here = (struct hashentry *) (mapped->data + work); |
| 492 | ref_t here_key, here_packet; |
| 493 | |
| 494 | #if !_STRING_ARCH_unaligned |
| 495 | /* Although during garbage collection when moving struct hashentry |
| 496 | records around we first copy from old to new location and then |
| 497 | adjust pointer from previous hashentry to it, there is no barrier |
| 498 | between those memory writes. It is very unlikely to hit it, |
| 499 | so check alignment only if a misaligned load can crash the |
| 500 | application. */ |
| 501 | if ((uintptr_t) here & (__alignof__ (*here) - 1)) |
| 502 | return NULL; |
| 503 | #endif |
| 504 | |
| 505 | if (type == here->type |
| 506 | && keylen == here->len |
| 507 | && (here_key = atomic_forced_read (here->key)) + keylen <= datasize |
| 508 | && memcmp (key, mapped->data + here_key, keylen) == 0 |
| 509 | && ((here_packet = atomic_forced_read (here->packet)) |
| 510 | + sizeof (struct datahead) <= datasize)) |
| 511 | { |
| 512 | /* We found the entry. Increment the appropriate counter. */ |
| 513 | struct datahead *dh |
| 514 | = (struct datahead *) (mapped->data + here_packet); |
| 515 | |
| 516 | #if !_STRING_ARCH_unaligned |
| 517 | if ((uintptr_t) dh & (__alignof__ (*dh) - 1)) |
| 518 | return NULL; |
| 519 | #endif |
| 520 | |
| 521 | /* See whether we must ignore the entry or whether something |
| 522 | is wrong because garbage collection is in progress. */ |
| 523 | if (dh->usable |
| 524 | && here_packet + dh->allocsize <= datasize |
| 525 | && (here_packet + offsetof (struct datahead, data) + datalen |
| 526 | <= datasize)) |
| 527 | return dh; |
| 528 | } |
| 529 | |
| 530 | work = atomic_forced_read (here->next); |
| 531 | /* Prevent endless loops. This should never happen but perhaps |
| 532 | the database got corrupted, accidentally or deliberately. */ |
| 533 | if (work == trail || loop_cnt-- == 0) |
| 534 | break; |
| 535 | if (tick) |
| 536 | { |
| 537 | struct hashentry *trailelem; |
| 538 | trailelem = (struct hashentry *) (mapped->data + trail); |
| 539 | |
| 540 | #if !_STRING_ARCH_unaligned |
| 541 | /* We have to redo the checks. Maybe the data changed. */ |
| 542 | if ((uintptr_t) trailelem & (__alignof__ (*trailelem) - 1)) |
| 543 | return NULL; |
| 544 | #endif |
| 545 | |
| 546 | if (trail + MINIMUM_HASHENTRY_SIZE > datasize) |
| 547 | return NULL; |
| 548 | |
| 549 | trail = atomic_forced_read (trailelem->next); |
| 550 | } |
| 551 | tick = 1 - tick; |
| 552 | } |
| 553 | |
| 554 | return NULL; |
| 555 | } |
| 556 | |
| 557 | |
| 558 | /* Create a socket connected to a name. */ |
| 559 | int |
| 560 | __nscd_open_socket (const char *key, size_t keylen, request_type type, |
| 561 | void *response, size_t responselen) |
| 562 | { |
| 563 | /* This should never happen and it is something the nscd daemon |
| 564 | enforces, too. He it helps to limit the amount of stack |
| 565 | used. */ |
| 566 | if (keylen > MAXKEYLEN) |
| 567 | return -1; |
| 568 | |
| 569 | int saved_errno = errno; |
| 570 | |
| 571 | int sock = open_socket (type, key, keylen); |
| 572 | if (sock >= 0) |
| 573 | { |
| 574 | /* Wait for data. */ |
| 575 | if (wait_on_socket (sock, 5 * 1000) > 0) |
| 576 | { |
| 577 | ssize_t nbytes = TEMP_FAILURE_RETRY (__read (sock, response, |
| 578 | responselen)); |
| 579 | if (nbytes == (ssize_t) responselen) |
| 580 | return sock; |
| 581 | } |
| 582 | |
| 583 | close_not_cancel_no_status (sock); |
| 584 | } |
| 585 | |
| 586 | __set_errno (saved_errno); |
| 587 | |
| 588 | return -1; |
| 589 | } |