1 /* $OpenBSD: asr.c,v 1.61 2018/10/22 17:31:24 krw Exp $ */ 2 /* 3 * Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/types.h> 19 #include <sys/socket.h> 20 #include <sys/stat.h> 21 #include <netinet/in.h> 22 #include <arpa/inet.h> 23 #include <arpa/nameser.h> 24 #include <netdb.h> 25 26 #include <asr.h> 27 #include <errno.h> 28 #include <fcntl.h> 29 #include <resolv.h> 30 #include <poll.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <unistd.h> 35 #include <limits.h> 36 37 #include "asr_private.h" 38 39 #include "thread_private.h" 40 41 #define DEFAULT_CONF "lookup file\n" 42 #define DEFAULT_LOOKUP "lookup bind file" 43 44 #define RELOAD_DELAY 15 /* seconds */ 45 46 static void asr_check_reload(struct asr *); 47 static struct asr_ctx *asr_ctx_create(void); 48 static void asr_ctx_ref(struct asr_ctx *); 49 static void asr_ctx_free(struct asr_ctx *); 50 static int asr_ctx_add_searchdomain(struct asr_ctx *, const char *); 51 static int asr_ctx_from_file(struct asr_ctx *, const char *); 52 static int asr_ctx_from_string(struct asr_ctx *, const char *); 53 static int asr_ctx_parse(struct asr_ctx *, const char *); 54 static int asr_parse_nameserver(struct sockaddr *, const char *); 55 static int asr_ndots(const char *); 56 static void pass0(char **, int, struct asr_ctx *); 57 static int strsplit(char *, char **, int); 58 static void asr_ctx_envopts(struct asr_ctx *); 59 static void *__THREAD_NAME(_asr); 60 61 static struct asr *_asr = NULL; 62 63 /* Allocate and configure an async "resolver". */ 64 static void * 65 _asr_resolver(void) 66 { 67 static int init = 0; 68 struct asr *asr; 69 70 if (init == 0) { 71 #ifdef DEBUG 72 if (getenv("ASR_DEBUG")) 73 _asr_debug = stderr; 74 #endif 75 init = 1; 76 } 77 78 if ((asr = calloc(1, sizeof(*asr))) == NULL) 79 goto fail; 80 81 asr_check_reload(asr); 82 if (asr->a_ctx == NULL) { 83 if ((asr->a_ctx = asr_ctx_create()) == NULL) 84 goto fail; 85 if (asr_ctx_from_string(asr->a_ctx, DEFAULT_CONF) == -1) 86 goto fail; 87 asr_ctx_envopts(asr->a_ctx); 88 } 89 90 #ifdef DEBUG 91 _asr_dump_config(_asr_debug, asr); 92 #endif 93 return (asr); 94 95 fail: 96 if (asr) { 97 if (asr->a_ctx) 98 asr_ctx_free(asr->a_ctx); 99 free(asr); 100 } 101 102 return (NULL); 103 } 104 105 /* 106 * Free the "asr" async resolver (or the thread-local resolver if NULL). 107 * Drop the reference to the current context. 108 */ 109 void 110 _asr_resolver_done(void *arg) 111 { 112 struct asr *asr = arg; 113 struct asr **priv; 114 115 if (asr == NULL) { 116 priv = _THREAD_PRIVATE(_asr, _asr, &_asr); 117 if (*priv == NULL) 118 return; 119 asr = *priv; 120 *priv = NULL; 121 } 122 123 _asr_ctx_unref(asr->a_ctx); 124 free(asr); 125 } 126 127 /* 128 * Cancel an async query. 129 */ 130 void 131 asr_abort(struct asr_query *as) 132 { 133 _asr_async_free(as); 134 } 135 136 /* 137 * Resume the "as" async query resolution. Return one of ASYNC_COND, 138 * or ASYNC_DONE and put query-specific return values in the user-allocated 139 * memory at "ar". 140 */ 141 int 142 asr_run(struct asr_query *as, struct asr_result *ar) 143 { 144 int r, saved_errno = errno; 145 146 DPRINT("asr: asr_run(%p, %p) %s ctx=[%p]\n", as, ar, 147 _asr_querystr(as->as_type), as->as_ctx); 148 r = as->as_run(as, ar); 149 150 DPRINT("asr: asr_run(%p, %p) -> %s", as, ar, _asr_transitionstr(r)); 151 #ifdef DEBUG 152 if (r == ASYNC_COND) 153 #endif 154 DPRINT(" fd=%i timeout=%i", ar->ar_fd, ar->ar_timeout); 155 DPRINT("\n"); 156 if (r == ASYNC_DONE) 157 _asr_async_free(as); 158 159 errno = saved_errno; 160 161 return (r); 162 } 163 DEF_WEAK(asr_run); 164 165 static int 166 poll_intrsafe(struct pollfd *fds, nfds_t nfds, int timeout) 167 { 168 struct timespec pollstart, pollend, elapsed; 169 int r; 170 171 if (clock_gettime(CLOCK_MONOTONIC, &pollstart)) 172 return -1; 173 174 while ((r = poll(fds, 1, timeout)) == -1 && errno == EINTR) { 175 if (clock_gettime(CLOCK_MONOTONIC, &pollend)) 176 return -1; 177 timespecsub(&pollend, &pollstart, &elapsed); 178 timeout -= elapsed.tv_sec * 1000 + elapsed.tv_nsec / 1000000; 179 if (timeout < 1) 180 return 0; 181 } 182 183 return r; 184 } 185 186 /* 187 * Same as asr_run, but run in a loop that handles the fd conditions result. 188 */ 189 int 190 asr_run_sync(struct asr_query *as, struct asr_result *ar) 191 { 192 struct pollfd fds[1]; 193 int r, saved_errno = errno; 194 195 while ((r = asr_run(as, ar)) == ASYNC_COND) { 196 fds[0].fd = ar->ar_fd; 197 fds[0].events = (ar->ar_cond == ASR_WANT_READ) ? POLLIN:POLLOUT; 198 199 if (poll_intrsafe(fds, 1, ar->ar_timeout) == -1) { 200 memset(ar, 0, sizeof(*ar)); 201 ar->ar_errno = errno; 202 ar->ar_h_errno = NETDB_INTERNAL; 203 ar->ar_gai_errno = EAI_SYSTEM; 204 ar->ar_rrset_errno = NETDB_INTERNAL; 205 _asr_async_free(as); 206 errno = saved_errno; 207 return ASYNC_DONE; 208 } 209 210 /* 211 * Otherwise, just ignore the error and let asr_run() 212 * catch the failure. 213 */ 214 } 215 216 errno = saved_errno; 217 218 return (r); 219 } 220 DEF_WEAK(asr_run_sync); 221 222 /* 223 * Create a new async request of the given "type" on the async context "ac". 224 * Take a reference on it so it does not get deleted while the async query 225 * is running. 226 */ 227 struct asr_query * 228 _asr_async_new(struct asr_ctx *ac, int type) 229 { 230 struct asr_query *as; 231 232 DPRINT("asr: asr_async_new(ctx=%p) type=%i refcount=%i\n", ac, type, 233 ac ? ac->ac_refcount : 0); 234 if (ac == NULL || (as = calloc(1, sizeof(*as))) == NULL) 235 return (NULL); 236 237 ac->ac_refcount += 1; 238 as->as_ctx = ac; 239 as->as_fd = -1; 240 as->as_type = type; 241 as->as_state = ASR_STATE_INIT; 242 243 return (as); 244 } 245 246 /* 247 * Free an async query and unref the associated context. 248 */ 249 void 250 _asr_async_free(struct asr_query *as) 251 { 252 DPRINT("asr: asr_async_free(%p)\n", as); 253 254 if (as->as_subq) 255 _asr_async_free(as->as_subq); 256 257 switch (as->as_type) { 258 case ASR_SEND: 259 if (as->as_fd != -1) 260 close(as->as_fd); 261 if (as->as.dns.obuf && !(as->as_flags & ASYNC_EXTOBUF)) 262 free(as->as.dns.obuf); 263 if (as->as.dns.ibuf) 264 free(as->as.dns.ibuf); 265 if (as->as.dns.dname) 266 free(as->as.dns.dname); 267 break; 268 269 case ASR_SEARCH: 270 if (as->as.search.name) 271 free(as->as.search.name); 272 break; 273 274 case ASR_GETRRSETBYNAME: 275 if (as->as.rrset.name) 276 free(as->as.rrset.name); 277 break; 278 279 case ASR_GETHOSTBYNAME: 280 case ASR_GETHOSTBYADDR: 281 if (as->as.hostnamadr.name) 282 free(as->as.hostnamadr.name); 283 break; 284 285 case ASR_GETADDRINFO: 286 if (as->as.ai.aifirst) 287 freeaddrinfo(as->as.ai.aifirst); 288 if (as->as.ai.hostname) 289 free(as->as.ai.hostname); 290 if (as->as.ai.servname) 291 free(as->as.ai.servname); 292 if (as->as.ai.fqdn) 293 free(as->as.ai.fqdn); 294 break; 295 296 case ASR_GETNAMEINFO: 297 break; 298 } 299 300 _asr_ctx_unref(as->as_ctx); 301 free(as); 302 } 303 304 /* 305 * Get a context from the given resolver. This takes a new reference to 306 * the returned context, which *must* be explicitly dropped when done 307 * using this context. 308 */ 309 struct asr_ctx * 310 _asr_use_resolver(void *arg) 311 { 312 struct asr *asr = arg; 313 struct asr **priv; 314 315 if (asr == NULL) { 316 DPRINT("using thread-local resolver\n"); 317 priv = _THREAD_PRIVATE(_asr, _asr, &_asr); 318 if (*priv == NULL) { 319 DPRINT("setting up thread-local resolver\n"); 320 *priv = _asr_resolver(); 321 } 322 asr = *priv; 323 } 324 if (asr != NULL) { 325 asr_check_reload(asr); 326 asr_ctx_ref(asr->a_ctx); 327 return (asr->a_ctx); 328 } 329 return (NULL); 330 } 331 332 static void 333 asr_ctx_ref(struct asr_ctx *ac) 334 { 335 DPRINT("asr: asr_ctx_ref(ctx=%p) refcount=%i\n", ac, ac->ac_refcount); 336 ac->ac_refcount += 1; 337 } 338 339 /* 340 * Drop a reference to an async context, freeing it if the reference 341 * count drops to 0. 342 */ 343 void 344 _asr_ctx_unref(struct asr_ctx *ac) 345 { 346 DPRINT("asr: asr_ctx_unref(ctx=%p) refcount=%i\n", ac, 347 ac ? ac->ac_refcount : 0); 348 if (ac == NULL) 349 return; 350 if (--ac->ac_refcount) 351 return; 352 353 asr_ctx_free(ac); 354 } 355 356 static void 357 asr_ctx_free(struct asr_ctx *ac) 358 { 359 int i; 360 361 if (ac->ac_domain) 362 free(ac->ac_domain); 363 for (i = 0; i < ASR_MAXNS; i++) 364 free(ac->ac_ns[i]); 365 for (i = 0; i < ASR_MAXDOM; i++) 366 free(ac->ac_dom[i]); 367 368 free(ac); 369 } 370 371 /* 372 * Reload the configuration file if it has changed on disk. 373 */ 374 static void 375 asr_check_reload(struct asr *asr) 376 { 377 struct asr_ctx *ac; 378 struct stat st; 379 struct timespec ts; 380 pid_t pid; 381 382 pid = getpid(); 383 if (pid != asr->a_pid) { 384 asr->a_pid = pid; 385 asr->a_rtime = 0; 386 } 387 388 if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1) 389 return; 390 391 if ((ts.tv_sec - asr->a_rtime) < RELOAD_DELAY && asr->a_rtime != 0) 392 return; 393 asr->a_rtime = ts.tv_sec; 394 395 DPRINT("asr: checking for update of \"%s\"\n", _PATH_RESCONF); 396 if (stat(_PATH_RESCONF, &st) == -1 || 397 asr->a_mtime == st.st_mtime || 398 (ac = asr_ctx_create()) == NULL) 399 return; 400 asr->a_mtime = st.st_mtime; 401 402 DPRINT("asr: reloading config file\n"); 403 if (asr_ctx_from_file(ac, _PATH_RESCONF) == -1) { 404 asr_ctx_free(ac); 405 return; 406 } 407 408 asr_ctx_envopts(ac); 409 if (asr->a_ctx) 410 _asr_ctx_unref(asr->a_ctx); 411 asr->a_ctx = ac; 412 } 413 414 /* 415 * Construct a fully-qualified domain name for the given name and domain. 416 * If "name" ends with a '.' it is considered as a FQDN by itself. 417 * Otherwise, the domain, which must be a FQDN, is appended to "name" (it 418 * may have a leading dot which would be ignored). If the domain is null, 419 * then "." is used. Return the length of the constructed FQDN or (0) on 420 * error. 421 */ 422 size_t 423 _asr_make_fqdn(const char *name, const char *domain, char *buf, size_t buflen) 424 { 425 size_t len; 426 427 if (domain == NULL) 428 domain = "."; 429 else if ((len = strlen(domain)) == 0) 430 return (0); 431 else if (domain[len -1] != '.') 432 return (0); 433 434 len = strlen(name); 435 if (len == 0) { 436 if (strlcpy(buf, domain, buflen) >= buflen) 437 return (0); 438 } else if (name[len - 1] != '.') { 439 if (domain[0] == '.') 440 domain += 1; 441 if (strlcpy(buf, name, buflen) >= buflen || 442 strlcat(buf, ".", buflen) >= buflen || 443 strlcat(buf, domain, buflen) >= buflen) 444 return (0); 445 } else { 446 if (strlcpy(buf, name, buflen) >= buflen) 447 return (0); 448 } 449 450 return (strlen(buf)); 451 } 452 453 /* 454 * Count the dots in a string. 455 */ 456 static int 457 asr_ndots(const char *s) 458 { 459 int n; 460 461 for (n = 0; *s; s++) 462 if (*s == '.') 463 n += 1; 464 465 return (n); 466 } 467 468 /* 469 * Allocate a new empty context. 470 */ 471 static struct asr_ctx * 472 asr_ctx_create(void) 473 { 474 struct asr_ctx *ac; 475 476 if ((ac = calloc(1, sizeof(*ac))) == NULL) 477 return (NULL); 478 479 ac->ac_options = RES_RECURSE | RES_DEFNAMES | RES_DNSRCH; 480 ac->ac_refcount = 1; 481 ac->ac_ndots = 1; 482 ac->ac_family[0] = AF_INET; 483 ac->ac_family[1] = AF_INET6; 484 ac->ac_family[2] = -1; 485 486 ac->ac_nscount = 0; 487 ac->ac_nstimeout = 5; 488 ac->ac_nsretries = 4; 489 490 return (ac); 491 } 492 493 struct asr_ctx * 494 _asr_no_resolver(void) 495 { 496 return asr_ctx_create(); 497 } 498 499 /* 500 * Add a search domain to the async context. 501 */ 502 static int 503 asr_ctx_add_searchdomain(struct asr_ctx *ac, const char *domain) 504 { 505 char buf[MAXDNAME]; 506 507 if (ac->ac_domcount == ASR_MAXDOM) 508 return (-1); 509 510 if (_asr_make_fqdn(domain, NULL, buf, sizeof(buf)) == 0) 511 return (-1); 512 513 if ((ac->ac_dom[ac->ac_domcount] = strdup(buf)) == NULL) 514 return (0); 515 516 ac->ac_domcount += 1; 517 518 return (1); 519 } 520 521 static int 522 strsplit(char *line, char **tokens, int ntokens) 523 { 524 int ntok; 525 char *cp, **tp; 526 527 for (cp = line, tp = tokens, ntok = 0; 528 ntok < ntokens && (*tp = strsep(&cp, " \t")) != NULL; ) 529 if (**tp != '\0') { 530 tp++; 531 ntok++; 532 } 533 534 return (ntok); 535 } 536 537 /* 538 * Pass on a split config line. 539 */ 540 static void 541 pass0(char **tok, int n, struct asr_ctx *ac) 542 { 543 int i, j, d; 544 const char *e; 545 struct sockaddr_storage ss; 546 547 if (!strcmp(tok[0], "nameserver")) { 548 if (ac->ac_nscount == ASR_MAXNS) 549 return; 550 if (n != 2) 551 return; 552 if (asr_parse_nameserver((struct sockaddr *)&ss, tok[1])) 553 return; 554 if ((ac->ac_ns[ac->ac_nscount] = calloc(1, ss.ss_len)) == NULL) 555 return; 556 memmove(ac->ac_ns[ac->ac_nscount], &ss, ss.ss_len); 557 ac->ac_nscount += 1; 558 559 } else if (!strcmp(tok[0], "domain")) { 560 if (n != 2) 561 return; 562 if (ac->ac_domain) 563 return; 564 ac->ac_domain = strdup(tok[1]); 565 566 } else if (!strcmp(tok[0], "lookup")) { 567 /* ensure that each lookup is only given once */ 568 for (i = 1; i < n; i++) 569 for (j = i + 1; j < n; j++) 570 if (!strcmp(tok[i], tok[j])) 571 return; 572 ac->ac_dbcount = 0; 573 for (i = 1; i < n && ac->ac_dbcount < ASR_MAXDB; i++) { 574 if (!strcmp(tok[i], "yp")) { 575 /* silently deprecated */ 576 } else if (!strcmp(tok[i], "bind")) 577 ac->ac_db[ac->ac_dbcount++] = ASR_DB_DNS; 578 else if (!strcmp(tok[i], "file")) 579 ac->ac_db[ac->ac_dbcount++] = ASR_DB_FILE; 580 } 581 } else if (!strcmp(tok[0], "search")) { 582 /* resolv.conf says the last line wins */ 583 for (i = 0; i < ASR_MAXDOM; i++) { 584 free(ac->ac_dom[i]); 585 ac->ac_dom[i] = NULL; 586 } 587 ac->ac_domcount = 0; 588 for (i = 1; i < n; i++) 589 asr_ctx_add_searchdomain(ac, tok[i]); 590 591 } else if (!strcmp(tok[0], "family")) { 592 if (n == 1 || n > 3) 593 return; 594 for (i = 1; i < n; i++) 595 if (strcmp(tok[i], "inet4") && strcmp(tok[i], "inet6")) 596 return; 597 for (i = 1; i < n; i++) 598 ac->ac_family[i - 1] = strcmp(tok[i], "inet4") ? \ 599 AF_INET6 : AF_INET; 600 ac->ac_family[i - 1] = -1; 601 602 } else if (!strcmp(tok[0], "options")) { 603 for (i = 1; i < n; i++) { 604 if (!strcmp(tok[i], "tcp")) 605 ac->ac_options |= RES_USEVC; 606 else if (!strcmp(tok[i], "edns0")) 607 ac->ac_options |= RES_USE_EDNS0; 608 else if ((!strncmp(tok[i], "ndots:", 6))) { 609 e = NULL; 610 d = strtonum(tok[i] + 6, 1, 16, &e); 611 if (e == NULL) 612 ac->ac_ndots = d; 613 } 614 } 615 } 616 } 617 618 /* 619 * Setup an async context with the config specified in the string "str". 620 */ 621 static int 622 asr_ctx_from_string(struct asr_ctx *ac, const char *str) 623 { 624 char buf[512], *ch; 625 626 asr_ctx_parse(ac, str); 627 628 if (ac->ac_dbcount == 0) { 629 /* No lookup directive */ 630 asr_ctx_parse(ac, DEFAULT_LOOKUP); 631 } 632 633 if (ac->ac_nscount == 0) 634 asr_ctx_parse(ac, "nameserver 127.0.0.1"); 635 636 if (ac->ac_domain == NULL) 637 if (gethostname(buf, sizeof buf) == 0) { 638 ch = strchr(buf, '.'); 639 if (ch) 640 ac->ac_domain = strdup(ch + 1); 641 else /* Assume root. see resolv.conf(5) */ 642 ac->ac_domain = strdup(""); 643 } 644 645 /* If no search domain was specified, use the local subdomains */ 646 if (ac->ac_domcount == 0) 647 for (ch = ac->ac_domain; ch; ) { 648 asr_ctx_add_searchdomain(ac, ch); 649 ch = strchr(ch, '.'); 650 if (ch && asr_ndots(++ch) == 0) 651 break; 652 } 653 654 return (0); 655 } 656 657 /* 658 * Setup the "ac" async context from the file at location "path". 659 */ 660 static int 661 asr_ctx_from_file(struct asr_ctx *ac, const char *path) 662 { 663 FILE *cf; 664 char buf[4096]; 665 ssize_t r; 666 667 cf = fopen(path, "re"); 668 if (cf == NULL) 669 return (-1); 670 671 r = fread(buf, 1, sizeof buf - 1, cf); 672 if (feof(cf) == 0) { 673 DPRINT("asr: config file too long: \"%s\"\n", path); 674 r = -1; 675 } 676 fclose(cf); 677 if (r == -1) 678 return (-1); 679 buf[r] = '\0'; 680 681 return asr_ctx_from_string(ac, buf); 682 } 683 684 /* 685 * Parse lines in the configuration string. For each one, split it into 686 * tokens and pass them to "pass0" for processing. 687 */ 688 static int 689 asr_ctx_parse(struct asr_ctx *ac, const char *str) 690 { 691 size_t len; 692 const char *line; 693 char buf[1024]; 694 char *tok[10]; 695 int ntok; 696 697 line = str; 698 while (*line) { 699 len = strcspn(line, "\n\0"); 700 if (len < sizeof buf) { 701 memmove(buf, line, len); 702 buf[len] = '\0'; 703 } else 704 buf[0] = '\0'; 705 line += len; 706 if (*line == '\n') 707 line++; 708 buf[strcspn(buf, ";#")] = '\0'; 709 if ((ntok = strsplit(buf, tok, 10)) == 0) 710 continue; 711 712 pass0(tok, ntok, ac); 713 } 714 715 return (0); 716 } 717 718 /* 719 * Check for environment variables altering the configuration as described 720 * in resolv.conf(5). Although not documented there, this feature is disabled 721 * for setuid/setgid programs. 722 */ 723 static void 724 asr_ctx_envopts(struct asr_ctx *ac) 725 { 726 char buf[4096], *e; 727 size_t s; 728 729 if (issetugid()) { 730 ac->ac_options |= RES_NOALIASES; 731 return; 732 } 733 734 if ((e = getenv("RES_OPTIONS")) != NULL) { 735 strlcpy(buf, "options ", sizeof buf); 736 strlcat(buf, e, sizeof buf); 737 s = strlcat(buf, "\n", sizeof buf); 738 if (s < sizeof buf) 739 asr_ctx_parse(ac, buf); 740 } 741 742 if ((e = getenv("LOCALDOMAIN")) != NULL) { 743 strlcpy(buf, "search ", sizeof buf); 744 strlcat(buf, e, sizeof buf); 745 s = strlcat(buf, "\n", sizeof buf); 746 if (s < sizeof buf) 747 asr_ctx_parse(ac, buf); 748 } 749 } 750 751 /* 752 * Parse a resolv.conf(5) nameserver string into a sockaddr. 753 */ 754 static int 755 asr_parse_nameserver(struct sockaddr *sa, const char *s) 756 { 757 in_port_t portno = 53; 758 759 if (_asr_sockaddr_from_str(sa, PF_UNSPEC, s) == -1) 760 return (-1); 761 762 if (sa->sa_family == PF_INET) 763 ((struct sockaddr_in *)sa)->sin_port = htons(portno); 764 else if (sa->sa_family == PF_INET6) 765 ((struct sockaddr_in6 *)sa)->sin6_port = htons(portno); 766 767 return (0); 768 } 769 770 /* 771 * Turn a (uncompressed) DNS domain name into a regular nul-terminated string 772 * where labels are separated by dots. The result is put into the "buf" buffer, 773 * truncated if it exceeds "max" chars. The function returns "buf". 774 */ 775 char * 776 _asr_strdname(const char *_dname, char *buf, size_t max) 777 { 778 const unsigned char *dname = _dname; 779 char *res; 780 size_t left, n, count; 781 782 if (_dname[0] == 0) { 783 strlcpy(buf, ".", max); 784 return buf; 785 } 786 787 res = buf; 788 left = max - 1; 789 for (n = 0; dname[0] && left; n += dname[0]) { 790 count = (dname[0] < (left - 1)) ? dname[0] : (left - 1); 791 memmove(buf, dname + 1, count); 792 dname += dname[0] + 1; 793 left -= count; 794 buf += count; 795 if (left) { 796 left -= 1; 797 *buf++ = '.'; 798 } 799 } 800 buf[0] = 0; 801 802 return (res); 803 } 804 805 /* 806 * Read and split the next line from the given namedb file. 807 * Return -1 on error, or put the result in the "tokens" array of 808 * size "ntoken" and returns the number of token on the line. 809 */ 810 int 811 _asr_parse_namedb_line(FILE *file, char **tokens, int ntoken, char *lbuf, size_t sz) 812 { 813 size_t len; 814 char *buf; 815 int ntok; 816 817 again: 818 if ((buf = fgetln(file, &len)) == NULL) 819 return (-1); 820 821 if (len >= sz) 822 goto again; 823 824 if (buf[len - 1] == '\n') 825 len--; 826 else { 827 memcpy(lbuf, buf, len); 828 buf = lbuf; 829 } 830 831 buf[len] = '\0'; 832 buf[strcspn(buf, "#")] = '\0'; 833 if ((ntok = strsplit(buf, tokens, ntoken)) == 0) 834 goto again; 835 836 return (ntok); 837 } 838 839 /* 840 * Update the async context so that it uses the next configured DB. 841 * Return 0 on success, or -1 if no more DBs is available. 842 */ 843 int 844 _asr_iter_db(struct asr_query *as) 845 { 846 if (as->as_db_idx >= as->as_ctx->ac_dbcount) { 847 DPRINT("asr_iter_db: done\n"); 848 return (-1); 849 } 850 851 as->as_db_idx += 1; 852 DPRINT("asr_iter_db: %i\n", as->as_db_idx); 853 854 return (0); 855 } 856