1 /* $OpenBSD: asr.c,v 1.57 2017/02/27 10:44:46 jca 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 /* 166 * Same as above, but run in a loop that handles the fd conditions result. 167 */ 168 int 169 asr_run_sync(struct asr_query *as, struct asr_result *ar) 170 { 171 struct pollfd fds[1]; 172 struct timespec pollstart, pollend, elapsed; 173 int timeout, r, p, saved_errno = errno; 174 175 while ((r = asr_run(as, ar)) == ASYNC_COND) { 176 fds[0].fd = ar->ar_fd; 177 fds[0].events = (ar->ar_cond == ASR_WANT_READ) ? POLLIN:POLLOUT; 178 179 timeout = ar->ar_timeout; 180 again: 181 if (clock_gettime(CLOCK_MONOTONIC, &pollstart)) 182 break; 183 p = poll(fds, 1, timeout); 184 if (p == -1 && errno == EINTR) { 185 if (clock_gettime(CLOCK_MONOTONIC, &pollend)) 186 break; 187 188 timespecsub(&pollend, &pollstart, &elapsed); 189 timeout -= (elapsed.tv_sec * 1000) + 190 (elapsed.tv_nsec / 1000000); 191 if (timeout < 1) 192 break; 193 goto again; 194 } 195 196 /* 197 * Otherwise, just ignore the error and let asr_run() 198 * catch the failure. 199 */ 200 } 201 202 errno = saved_errno; 203 204 return (r); 205 } 206 DEF_WEAK(asr_run_sync); 207 208 /* 209 * Create a new async request of the given "type" on the async context "ac". 210 * Take a reference on it so it does not gets deleted while the async query 211 * is running. 212 */ 213 struct asr_query * 214 _asr_async_new(struct asr_ctx *ac, int type) 215 { 216 struct asr_query *as; 217 218 DPRINT("asr: asr_async_new(ctx=%p) type=%i refcount=%i\n", ac, type, 219 ac ? ac->ac_refcount : 0); 220 if (ac == NULL || (as = calloc(1, sizeof(*as))) == NULL) 221 return (NULL); 222 223 ac->ac_refcount += 1; 224 as->as_ctx = ac; 225 as->as_fd = -1; 226 as->as_type = type; 227 as->as_state = ASR_STATE_INIT; 228 229 return (as); 230 } 231 232 /* 233 * Free an async query and unref the associated context. 234 */ 235 void 236 _asr_async_free(struct asr_query *as) 237 { 238 DPRINT("asr: asr_async_free(%p)\n", as); 239 240 if (as->as_subq) 241 _asr_async_free(as->as_subq); 242 243 switch (as->as_type) { 244 case ASR_SEND: 245 if (as->as_fd != -1) 246 close(as->as_fd); 247 if (as->as.dns.obuf && !(as->as_flags & ASYNC_EXTOBUF)) 248 free(as->as.dns.obuf); 249 if (as->as.dns.ibuf) 250 free(as->as.dns.ibuf); 251 if (as->as.dns.dname) 252 free(as->as.dns.dname); 253 break; 254 255 case ASR_SEARCH: 256 if (as->as.search.name) 257 free(as->as.search.name); 258 break; 259 260 case ASR_GETRRSETBYNAME: 261 if (as->as.rrset.name) 262 free(as->as.rrset.name); 263 break; 264 265 case ASR_GETHOSTBYNAME: 266 case ASR_GETHOSTBYADDR: 267 if (as->as.hostnamadr.name) 268 free(as->as.hostnamadr.name); 269 break; 270 271 case ASR_GETNETBYNAME: 272 case ASR_GETNETBYADDR: 273 if (as->as.netnamadr.name) 274 free(as->as.netnamadr.name); 275 break; 276 277 case ASR_GETADDRINFO: 278 if (as->as.ai.aifirst) 279 freeaddrinfo(as->as.ai.aifirst); 280 if (as->as.ai.hostname) 281 free(as->as.ai.hostname); 282 if (as->as.ai.servname) 283 free(as->as.ai.servname); 284 if (as->as.ai.fqdn) 285 free(as->as.ai.fqdn); 286 break; 287 288 case ASR_GETNAMEINFO: 289 break; 290 } 291 292 _asr_ctx_unref(as->as_ctx); 293 free(as); 294 } 295 296 /* 297 * Get a context from the given resolver. This takes a new reference to 298 * the returned context, which *must* be explicitely dropped when done 299 * using this context. 300 */ 301 struct asr_ctx * 302 _asr_use_resolver(void *arg) 303 { 304 struct asr *asr = arg; 305 struct asr **priv; 306 307 if (asr == NULL) { 308 DPRINT("using thread-local resolver\n"); 309 priv = _THREAD_PRIVATE(_asr, _asr, &_asr); 310 if (*priv == NULL) { 311 DPRINT("setting up thread-local resolver\n"); 312 *priv = _asr_resolver(); 313 } 314 asr = *priv; 315 } 316 if (asr != NULL) { 317 asr_check_reload(asr); 318 asr_ctx_ref(asr->a_ctx); 319 return (asr->a_ctx); 320 } 321 return (NULL); 322 } 323 324 static void 325 asr_ctx_ref(struct asr_ctx *ac) 326 { 327 DPRINT("asr: asr_ctx_ref(ctx=%p) refcount=%i\n", ac, ac->ac_refcount); 328 ac->ac_refcount += 1; 329 } 330 331 /* 332 * Drop a reference to an async context, freeing it if the reference 333 * count drops to 0. 334 */ 335 void 336 _asr_ctx_unref(struct asr_ctx *ac) 337 { 338 DPRINT("asr: asr_ctx_unref(ctx=%p) refcount=%i\n", ac, 339 ac ? ac->ac_refcount : 0); 340 if (ac == NULL) 341 return; 342 if (--ac->ac_refcount) 343 return; 344 345 asr_ctx_free(ac); 346 } 347 348 static void 349 asr_ctx_free(struct asr_ctx *ac) 350 { 351 int i; 352 353 if (ac->ac_domain) 354 free(ac->ac_domain); 355 for (i = 0; i < ASR_MAXNS; i++) 356 free(ac->ac_ns[i]); 357 for (i = 0; i < ASR_MAXDOM; i++) 358 free(ac->ac_dom[i]); 359 360 free(ac); 361 } 362 363 /* 364 * Reload the configuration file if it has changed on disk. 365 */ 366 static void 367 asr_check_reload(struct asr *asr) 368 { 369 struct asr_ctx *ac; 370 struct stat st; 371 struct timespec ts; 372 pid_t pid; 373 374 pid = getpid(); 375 if (pid != asr->a_pid) { 376 asr->a_pid = pid; 377 asr->a_rtime = 0; 378 } 379 380 if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1) 381 return; 382 383 if ((ts.tv_sec - asr->a_rtime) < RELOAD_DELAY && asr->a_rtime != 0) 384 return; 385 asr->a_rtime = ts.tv_sec; 386 387 DPRINT("asr: checking for update of \"%s\"\n", _PATH_RESCONF); 388 if (stat(_PATH_RESCONF, &st) == -1 || 389 asr->a_mtime == st.st_mtime || 390 (ac = asr_ctx_create()) == NULL) 391 return; 392 asr->a_mtime = st.st_mtime; 393 394 DPRINT("asr: reloading config file\n"); 395 if (asr_ctx_from_file(ac, _PATH_RESCONF) == -1) { 396 asr_ctx_free(ac); 397 return; 398 } 399 400 asr_ctx_envopts(ac); 401 if (asr->a_ctx) 402 _asr_ctx_unref(asr->a_ctx); 403 asr->a_ctx = ac; 404 } 405 406 /* 407 * Construct a fully-qualified domain name for the given name and domain. 408 * If "name" ends with a '.' it is considered as a FQDN by itself. 409 * Otherwise, the domain, which must be a FQDN, is appended to "name" (it 410 * may have a leading dot which would be ignored). If the domain is null, 411 * then "." is used. Return the length of the constructed FQDN or (0) on 412 * error. 413 */ 414 size_t 415 _asr_make_fqdn(const char *name, const char *domain, char *buf, size_t buflen) 416 { 417 size_t len; 418 419 if (domain == NULL) 420 domain = "."; 421 else if ((len = strlen(domain)) == 0) 422 return (0); 423 else if (domain[len -1] != '.') 424 return (0); 425 426 len = strlen(name); 427 if (len == 0) { 428 if (strlcpy(buf, domain, buflen) >= buflen) 429 return (0); 430 } else if (name[len - 1] != '.') { 431 if (domain[0] == '.') 432 domain += 1; 433 if (strlcpy(buf, name, buflen) >= buflen || 434 strlcat(buf, ".", buflen) >= buflen || 435 strlcat(buf, domain, buflen) >= buflen) 436 return (0); 437 } else { 438 if (strlcpy(buf, name, buflen) >= buflen) 439 return (0); 440 } 441 442 return (strlen(buf)); 443 } 444 445 /* 446 * Count the dots in a string. 447 */ 448 static int 449 asr_ndots(const char *s) 450 { 451 int n; 452 453 for (n = 0; *s; s++) 454 if (*s == '.') 455 n += 1; 456 457 return (n); 458 } 459 460 /* 461 * Allocate a new empty context. 462 */ 463 static struct asr_ctx * 464 asr_ctx_create(void) 465 { 466 struct asr_ctx *ac; 467 468 if ((ac = calloc(1, sizeof(*ac))) == NULL) 469 return (NULL); 470 471 ac->ac_options = RES_RECURSE | RES_DEFNAMES | RES_DNSRCH; 472 ac->ac_refcount = 1; 473 ac->ac_ndots = 1; 474 ac->ac_family[0] = AF_INET; 475 ac->ac_family[1] = AF_INET6; 476 ac->ac_family[2] = -1; 477 478 ac->ac_nscount = 0; 479 ac->ac_nstimeout = 5; 480 ac->ac_nsretries = 4; 481 482 return (ac); 483 } 484 485 struct asr_ctx * 486 _asr_no_resolver(void) 487 { 488 return asr_ctx_create(); 489 } 490 491 /* 492 * Add a search domain to the async context. 493 */ 494 static int 495 asr_ctx_add_searchdomain(struct asr_ctx *ac, const char *domain) 496 { 497 char buf[MAXDNAME]; 498 499 if (ac->ac_domcount == ASR_MAXDOM) 500 return (-1); 501 502 if (_asr_make_fqdn(domain, NULL, buf, sizeof(buf)) == 0) 503 return (-1); 504 505 if ((ac->ac_dom[ac->ac_domcount] = strdup(buf)) == NULL) 506 return (0); 507 508 ac->ac_domcount += 1; 509 510 return (1); 511 } 512 513 static int 514 strsplit(char *line, char **tokens, int ntokens) 515 { 516 int ntok; 517 char *cp, **tp; 518 519 for (cp = line, tp = tokens, ntok = 0; 520 ntok < ntokens && (*tp = strsep(&cp, " \t")) != NULL; ) 521 if (**tp != '\0') { 522 tp++; 523 ntok++; 524 } 525 526 return (ntok); 527 } 528 529 /* 530 * Pass on a split config line. 531 */ 532 static void 533 pass0(char **tok, int n, struct asr_ctx *ac) 534 { 535 int i, j, d; 536 const char *e; 537 struct sockaddr_storage ss; 538 539 if (!strcmp(tok[0], "nameserver")) { 540 if (ac->ac_nscount == ASR_MAXNS) 541 return; 542 if (n != 2) 543 return; 544 if (asr_parse_nameserver((struct sockaddr *)&ss, tok[1])) 545 return; 546 if ((ac->ac_ns[ac->ac_nscount] = calloc(1, ss.ss_len)) == NULL) 547 return; 548 memmove(ac->ac_ns[ac->ac_nscount], &ss, ss.ss_len); 549 ac->ac_nscount += 1; 550 551 } else if (!strcmp(tok[0], "domain")) { 552 if (n != 2) 553 return; 554 if (ac->ac_domain) 555 return; 556 ac->ac_domain = strdup(tok[1]); 557 558 } else if (!strcmp(tok[0], "lookup")) { 559 /* ensure that each lookup is only given once */ 560 for (i = 1; i < n; i++) 561 for (j = i + 1; j < n; j++) 562 if (!strcmp(tok[i], tok[j])) 563 return; 564 ac->ac_dbcount = 0; 565 for (i = 1; i < n && ac->ac_dbcount < ASR_MAXDB; i++) { 566 if (!strcmp(tok[i], "yp")) { 567 /* silently deprecated */ 568 } else if (!strcmp(tok[i], "bind")) 569 ac->ac_db[ac->ac_dbcount++] = ASR_DB_DNS; 570 else if (!strcmp(tok[i], "file")) 571 ac->ac_db[ac->ac_dbcount++] = ASR_DB_FILE; 572 } 573 } else if (!strcmp(tok[0], "search")) { 574 /* resolv.conf says the last line wins */ 575 for (i = 0; i < ASR_MAXDOM; i++) { 576 free(ac->ac_dom[i]); 577 ac->ac_dom[i] = NULL; 578 } 579 ac->ac_domcount = 0; 580 for (i = 1; i < n; i++) 581 asr_ctx_add_searchdomain(ac, tok[i]); 582 583 } else if (!strcmp(tok[0], "family")) { 584 if (n == 1 || n > 3) 585 return; 586 for (i = 1; i < n; i++) 587 if (strcmp(tok[i], "inet4") && strcmp(tok[i], "inet6")) 588 return; 589 for (i = 1; i < n; i++) 590 ac->ac_family[i - 1] = strcmp(tok[i], "inet4") ? \ 591 AF_INET6 : AF_INET; 592 ac->ac_family[i - 1] = -1; 593 594 } else if (!strcmp(tok[0], "options")) { 595 for (i = 1; i < n; i++) { 596 if (!strcmp(tok[i], "tcp")) 597 ac->ac_options |= RES_USEVC; 598 else if (!strcmp(tok[i], "edns0")) 599 ac->ac_options |= RES_USE_EDNS0; 600 else if ((!strncmp(tok[i], "ndots:", 6))) { 601 e = NULL; 602 d = strtonum(tok[i] + 6, 1, 16, &e); 603 if (e == NULL) 604 ac->ac_ndots = d; 605 } 606 } 607 } 608 } 609 610 /* 611 * Setup an async context with the config specified in the string "str". 612 */ 613 static int 614 asr_ctx_from_string(struct asr_ctx *ac, const char *str) 615 { 616 char buf[512], *ch; 617 618 asr_ctx_parse(ac, str); 619 620 if (ac->ac_dbcount == 0) { 621 /* No lookup directive */ 622 asr_ctx_parse(ac, DEFAULT_LOOKUP); 623 } 624 625 if (ac->ac_nscount == 0) 626 asr_ctx_parse(ac, "nameserver 127.0.0.1"); 627 628 if (ac->ac_domain == NULL) 629 if (gethostname(buf, sizeof buf) == 0) { 630 ch = strchr(buf, '.'); 631 if (ch) 632 ac->ac_domain = strdup(ch + 1); 633 else /* Assume root. see resolv.conf(5) */ 634 ac->ac_domain = strdup(""); 635 } 636 637 /* If no search domain was specified, use the local subdomains */ 638 if (ac->ac_domcount == 0) 639 for (ch = ac->ac_domain; ch; ) { 640 asr_ctx_add_searchdomain(ac, ch); 641 ch = strchr(ch, '.'); 642 if (ch && asr_ndots(++ch) == 0) 643 break; 644 } 645 646 return (0); 647 } 648 649 /* 650 * Setup the "ac" async context from the file at location "path". 651 */ 652 static int 653 asr_ctx_from_file(struct asr_ctx *ac, const char *path) 654 { 655 FILE *cf; 656 char buf[4096]; 657 ssize_t r; 658 659 cf = fopen(path, "re"); 660 if (cf == NULL) 661 return (-1); 662 663 r = fread(buf, 1, sizeof buf - 1, cf); 664 if (feof(cf) == 0) { 665 DPRINT("asr: config file too long: \"%s\"\n", path); 666 r = -1; 667 } 668 fclose(cf); 669 if (r == -1) 670 return (-1); 671 buf[r] = '\0'; 672 673 return asr_ctx_from_string(ac, buf); 674 } 675 676 /* 677 * Parse lines in the configuration string. For each one, split it into 678 * tokens and pass them to "pass0" for processing. 679 */ 680 static int 681 asr_ctx_parse(struct asr_ctx *ac, const char *str) 682 { 683 size_t len; 684 const char *line; 685 char buf[1024]; 686 char *tok[10]; 687 int ntok; 688 689 line = str; 690 while (*line) { 691 len = strcspn(line, "\n\0"); 692 if (len < sizeof buf) { 693 memmove(buf, line, len); 694 buf[len] = '\0'; 695 } else 696 buf[0] = '\0'; 697 line += len; 698 if (*line == '\n') 699 line++; 700 buf[strcspn(buf, ";#")] = '\0'; 701 if ((ntok = strsplit(buf, tok, 10)) == 0) 702 continue; 703 704 pass0(tok, ntok, ac); 705 } 706 707 return (0); 708 } 709 710 /* 711 * Check for environment variables altering the configuration as described 712 * in resolv.conf(5). Although not documented there, this feature is disabled 713 * for setuid/setgid programs. 714 */ 715 static void 716 asr_ctx_envopts(struct asr_ctx *ac) 717 { 718 char buf[4096], *e; 719 size_t s; 720 721 if (issetugid()) { 722 ac->ac_options |= RES_NOALIASES; 723 return; 724 } 725 726 if ((e = getenv("RES_OPTIONS")) != NULL) { 727 strlcpy(buf, "options ", sizeof buf); 728 strlcat(buf, e, sizeof buf); 729 s = strlcat(buf, "\n", sizeof buf); 730 if (s < sizeof buf) 731 asr_ctx_parse(ac, buf); 732 } 733 734 if ((e = getenv("LOCALDOMAIN")) != NULL) { 735 strlcpy(buf, "search ", 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 } 742 743 /* 744 * Parse a resolv.conf(5) nameserver string into a sockaddr. 745 */ 746 static int 747 asr_parse_nameserver(struct sockaddr *sa, const char *s) 748 { 749 in_port_t portno = 53; 750 751 if (_asr_sockaddr_from_str(sa, PF_UNSPEC, s) == -1) 752 return (-1); 753 754 if (sa->sa_family == PF_INET) 755 ((struct sockaddr_in *)sa)->sin_port = htons(portno); 756 else if (sa->sa_family == PF_INET6) 757 ((struct sockaddr_in6 *)sa)->sin6_port = htons(portno); 758 759 return (0); 760 } 761 762 /* 763 * Turn a (uncompressed) DNS domain name into a regular nul-terminated string 764 * where labels are separated by dots. The result is put into the "buf" buffer, 765 * truncated if it exceeds "max" chars. The function returns "buf". 766 */ 767 char * 768 _asr_strdname(const char *_dname, char *buf, size_t max) 769 { 770 const unsigned char *dname = _dname; 771 char *res; 772 size_t left, n, count; 773 774 if (_dname[0] == 0) { 775 strlcpy(buf, ".", max); 776 return buf; 777 } 778 779 res = buf; 780 left = max - 1; 781 for (n = 0; dname[0] && left; n += dname[0]) { 782 count = (dname[0] < (left - 1)) ? dname[0] : (left - 1); 783 memmove(buf, dname + 1, count); 784 dname += dname[0] + 1; 785 left -= count; 786 buf += count; 787 if (left) { 788 left -= 1; 789 *buf++ = '.'; 790 } 791 } 792 buf[0] = 0; 793 794 return (res); 795 } 796 797 /* 798 * Read and split the next line from the given namedb file. 799 * Return -1 on error, or put the result in the "tokens" array of 800 * size "ntoken" and returns the number of token on the line. 801 */ 802 int 803 _asr_parse_namedb_line(FILE *file, char **tokens, int ntoken, char *lbuf, size_t sz) 804 { 805 size_t len; 806 char *buf; 807 int ntok; 808 809 again: 810 if ((buf = fgetln(file, &len)) == NULL) 811 return (-1); 812 813 if (len >= sz) 814 goto again; 815 816 if (buf[len - 1] == '\n') 817 len--; 818 else { 819 memcpy(lbuf, buf, len); 820 buf = lbuf; 821 } 822 823 buf[len] = '\0'; 824 buf[strcspn(buf, "#")] = '\0'; 825 if ((ntok = strsplit(buf, tokens, ntoken)) == 0) 826 goto again; 827 828 return (ntok); 829 } 830 831 /* 832 * Update the async context so that it uses the next configured DB. 833 * Return 0 on success, or -1 if no more DBs is available. 834 */ 835 int 836 _asr_iter_db(struct asr_query *as) 837 { 838 if (as->as_db_idx >= as->as_ctx->ac_dbcount) { 839 DPRINT("asr_iter_db: done\n"); 840 return (-1); 841 } 842 843 as->as_db_idx += 1; 844 DPRINT("asr_iter_db: %i\n", as->as_db_idx); 845 846 return (0); 847 } 848