resolv/res_init.c

   1 /* Resolver state initialization and resolv.conf parsing.
   2    Copyright (C) 1995-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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    <https://www.gnu.org/licenses/>.  */
  18
  19 /*
  20  * Copyright (c) 1985, 1989, 1993
  21  *    The Regents of the University of California.  All rights reserved.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the above copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 4. Neither the name of the University nor the names of its contributors
  32  *    may be used to endorse or promote products derived from this software
  33  *    without specific prior written permission.
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  36  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  38  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  39  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  40  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  41  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  42  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  43  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  44  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  45  * SUCH DAMAGE.
  46  */
  47
  48 /*
  49  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  50  *
  51  * Permission to use, copy, modify, and distribute this software for any
  52  * purpose with or without fee is hereby granted, provided that the above
  53  * copyright notice and this permission notice appear in all copies, and that
  54  * the name of Digital Equipment Corporation not be used in advertising or
  55  * publicity pertaining to distribution of the document or software without
  56  * specific, written prior permission.
  57  *
  58  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  59  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  60  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  61  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  62  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  63  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  64  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  65  * SOFTWARE.
  66  */
  67
  68 /*
  69  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  70  *
  71  * Permission to use, copy, modify, and distribute this software for any
  72  * purpose with or without fee is hereby granted, provided that the above
  73  * copyright notice and this permission notice appear in all copies.
  74  *
  75  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  76  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  77  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  78  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  79  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  80  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  81  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  82  * SOFTWARE.
  83  */
  84
  85 #include <ctype.h>
  86 #include <netdb.h>
  87 #include <resolv/resolv-internal.h>
  88 #include <res_hconf.h>
  89 #include <stdio.h>
  90 #include <stdio_ext.h>
  91 #include <stdlib.h>
  92 #include <string.h>
  93 #include <unistd.h>
  94 #include <stdint.h>
  95 #include <arpa/inet.h>
  96 #include <arpa/nameser.h>
  97 #include <net/if.h>
  98 #include <netinet/in.h>
  99 #include <sys/param.h>
 100 #include <sys/socket.h>
 101 #include <sys/time.h>
 102 #include <sys/types.h>
 103 #include <inet/net-internal.h>
 104 #include <errno.h>
 105 #include <resolv_conf.h>
 106 #include <file_change_detection.h>
 107
 108 static uint32_t net_mask (struct in_addr);
 109
 110 int
 111 res_ninit (res_state statp)
 112 {
 113   return __res_vinit (statp, 0);
 114 }
 115 libc_hidden_def (__res_ninit)
 116
 117 /* Return true if CH separates the netmask in the "sortlist"
 118    directive.  */
 119 static inline bool
 120 is_sort_mask (char ch)
 121 {
 122   return ch == '/' || ch == '&';
 123 }
 124
 125 /* Array of name server addresses.  */
 126 #define DYNARRAY_STRUCT nameserver_list
 127 #define DYNARRAY_ELEMENT const struct sockaddr *
 128 #define DYNARRAY_ELEMENT_FREE(e) free ((struct sockaddr *) *(e))
 129 #define DYNARRAY_INITIAL_SIZE 3
 130 #define DYNARRAY_PREFIX nameserver_list_
 131 #include <malloc/dynarray-skeleton.c>
 132
 133 /* Array of strings for the search array.  The backing store is
 134    managed separately.  */
 135 #define DYNARRAY_STRUCT search_list
 136 #define DYNARRAY_ELEMENT const char *
 137 #define DYNARRAY_INITIAL_SIZE 6
 138 #define DYNARRAY_PREFIX search_list_
 139 #include <malloc/dynarray-skeleton.c>
 140
 141 /* Array of name server addresses.  */
 142 #define DYNARRAY_STRUCT sort_list
 143 #define DYNARRAY_ELEMENT struct resolv_sortlist_entry
 144 #define DYNARRAY_INITIAL_SIZE 0
 145 #define DYNARRAY_PREFIX sort_list_
 146 #include <malloc/dynarray-skeleton.c>
 147
 148 /* resolv.conf parser state and results.  */
 149 struct resolv_conf_parser
 150 {
 151   char *buffer;            /* Temporary buffer for reading lines.  */
 152
 153   struct nameserver_list nameserver_list; /* Nameserver addresses.  */
 154
 155   char *search_list_store; /* Backing storage for search list entries.  */
 156   struct search_list search_list; /* Points into search_list_store.  */
 157
 158   struct sort_list sort_list;   /* Address preference sorting list.  */
 159
 160   /* Configuration template.  The non-array elements are filled in
 161      directly.  The array elements are updated prior to the call to
 162      __resolv_conf_attach.  */
 163   struct resolv_conf template;
 164 };
 165
 166 /* Return true if *PREINIT contains actual preinitialization.  */
 167 static bool
 168 has_preinit_values (const struct __res_state *preinit)
 169 {
 170   return (preinit->retrans != 0 && preinit->retrans != RES_TIMEOUT)
 171     || (preinit->retry != 0 && preinit->retry != RES_DFLRETRY)
 172     || (preinit->options != 0
 173         && (preinit->options & ~RES_INIT) != RES_DEFAULT);
 174 }
 175
 176 static void
 177 resolv_conf_parser_init (struct resolv_conf_parser *parser,
 178                          const struct __res_state *preinit)
 179 {
 180   parser->buffer = NULL;
 181   parser->search_list_store = NULL;
 182   nameserver_list_init (&parser->nameserver_list);
 183   search_list_init (&parser->search_list);
 184   sort_list_init (&parser->sort_list);
 185
 186   if (preinit != NULL)
 187     {
 188       parser->template.retrans = preinit->retrans;
 189       parser->template.retry = preinit->retry;
 190       parser->template.options = preinit->options | RES_INIT;
 191     }
 192   else
 193     {
 194       parser->template.retrans = RES_TIMEOUT;
 195       parser->template.retry = RES_DFLRETRY;
 196       parser->template.options = RES_DEFAULT | RES_INIT;
 197     }
 198   parser->template.ndots = 1;
 199 }
 200
 201 static void
 202 resolv_conf_parser_free (struct resolv_conf_parser *parser)
 203 {
 204   free (parser->buffer);
 205   free (parser->search_list_store);
 206   nameserver_list_free (&parser->nameserver_list);
 207   search_list_free (&parser->search_list);
 208   sort_list_free (&parser->sort_list);
 209 }
 210
 211 /* Allocate a struct sockaddr_in object on the heap, with the
 212    specified address and port.  */
 213 static struct sockaddr *
 214 allocate_address_v4 (struct in_addr a, uint16_t port)
 215 {
 216   struct sockaddr_in *sa4 = malloc (sizeof (*sa4));
 217   if (sa4 == NULL)
 218     return NULL;
 219   sa4->sin_family = AF_INET;
 220   sa4->sin_addr = a;
 221   sa4->sin_port = htons (port);
 222   return (struct sockaddr *) sa4;
 223 }
 224
 225 /* Try to obtain the domain name from the host name and store it in
 226    *RESULT.  Return false on memory allocation failure.  If the domain
 227    name cannot be determined for any other reason, write NULL to
 228    *RESULT and return true.  */
 229 static bool
 230 domain_from_hostname (char **result)
 231 {
 232   char buf[256];
 233   /* gethostbyname may not terminate the buffer.  */
 234   buf[sizeof (buf) - 1] = '\0';
 235   if (__gethostname (buf, sizeof (buf) - 1) == 0)
 236     {
 237       char *dot = strchr (buf, '.');
 238       if (dot != NULL)
 239         {
 240           *result = __strdup (dot + 1);
 241           if (*result == NULL)
 242             return false;
 243           return true;
 244         }
 245     }
 246   *result = NULL;
 247   return true;
 248 }
 249
 250 static void res_setoptions (struct resolv_conf_parser *, const char *options);
 251
 252 /* Internal helper function for __res_vinit, to aid with resource
 253    deallocation and error handling.  Return true on success, false on
 254    failure.  */
 255 static bool
 256 res_vinit_1 (FILE *fp, struct resolv_conf_parser *parser)
 257 {
 258   char *cp;
 259   size_t buffer_size = 0;
 260   bool haveenv = false;
 261
 262   /* Allow user to override the local domain definition.  */
 263   if ((cp = getenv ("LOCALDOMAIN")) != NULL)
 264     {
 265       /* The code below splits the string in place.  */
 266       cp = __strdup (cp);
 267       if (cp == NULL)
 268         return false;
 269       free (parser->search_list_store);
 270       parser->search_list_store = cp;
 271       haveenv = true;
 272
 273       /* The string will be truncated as needed below.  */
 274       search_list_add (&parser->search_list, cp);
 275
 276       /* Set search list to be blank-separated strings from rest of
 277          env value.  Permits users of LOCALDOMAIN to still have a
 278          search list, and anyone to set the one that they want to use
 279          as an individual (even more important now that the rfc1535
 280          stuff restricts searches).  */
 281       for (bool in_name = true; *cp != '\0'; cp++)
 282         {
 283           if (*cp == '\n')
 284             {
 285               *cp = '\0';
 286               break;
 287             }
 288           else if (*cp == ' ' || *cp == '\t')
 289             {
 290               *cp = '\0';
 291               in_name = false;
 292             }
 293           else if (!in_name)
 294             {
 295               search_list_add (&parser->search_list, cp);
 296               in_name = true;
 297             }
 298         }
 299     }
 300
 301 #define MATCH(line, name)                       \
 302   (!strncmp ((line), name, sizeof (name) - 1)     \
 303    && ((line)[sizeof (name) - 1] == ' '           \
 304        || (line)[sizeof (name) - 1] == '\t'))
 305
 306   if (fp != NULL)
 307     {
 308       /* No threads use this stream.  */
 309       __fsetlocking (fp, FSETLOCKING_BYCALLER);
 310       /* Read the config file.  */
 311       while (true)
 312         {
 313           {
 314             ssize_t ret = __getline (&parser->buffer, &buffer_size, fp);
 315             if (ret <= 0)
 316               {
 317                 if (_IO_ferror_unlocked (fp))
 318                   return false;
 319                 else
 320                   break;
 321               }
 322           }
 323
 324           /* Skip comments.  */
 325           if (*parser->buffer == ';' || *parser->buffer == '#')
 326             continue;
 327           /* Read default domain name.  */
 328           if (MATCH (parser->buffer, "domain"))
 329             {
 330               if (haveenv)
 331                 /* LOCALDOMAIN overrides the configuration file.  */
 332                 continue;
 333               cp = parser->buffer + sizeof ("domain") - 1;
 334               while (*cp == ' ' || *cp == '\t')
 335                 cp++;
 336               if ((*cp == '\0') || (*cp == '\n'))
 337                 continue;
 338
 339               cp = __strdup (cp);
 340               if (cp == NULL)
 341                 return false;
 342               free (parser->search_list_store);
 343               parser->search_list_store = cp;
 344               search_list_clear (&parser->search_list);
 345               search_list_add (&parser->search_list, cp);
 346               /* Replace trailing whitespace.  */
 347               if ((cp = strpbrk (cp, " \t\n")) != NULL)
 348                 *cp = '\0';
 349               continue;
 350             }
 351           /* Set search list.  */
 352           if (MATCH (parser->buffer, "search"))
 353             {
 354               if (haveenv)
 355                 /* LOCALDOMAIN overrides the configuration file.  */
 356                 continue;
 357               cp = parser->buffer + sizeof ("search") - 1;
 358               while (*cp == ' ' || *cp == '\t')
 359                 cp++;
 360               if ((*cp == '\0') || (*cp == '\n'))
 361                 continue;
 362
 363               {
 364                 char *p = strchr (cp, '\n');
 365                 if (p != NULL)
 366                   *p = '\0';
 367               }
 368               cp = __strdup (cp);
 369               if (cp == NULL)
 370                 return false;
 371               free (parser->search_list_store);
 372               parser->search_list_store = cp;
 373
 374               /* The string is truncated below.  */
 375               search_list_clear (&parser->search_list);
 376               search_list_add (&parser->search_list, cp);
 377
 378               /* Set search list to be blank-separated strings on rest
 379                  of line.  */
 380               for (bool in_name = true; *cp != '\0'; cp++)
 381                 {
 382                   if (*cp == ' ' || *cp == '\t')
 383                     {
 384                       *cp = '\0';
 385                       in_name = false;
 386                     }
 387                   else if (!in_name)
 388                     {
 389                       search_list_add (&parser->search_list, cp);
 390                       in_name = true;
 391                     }
 392                 }
 393               continue;
 394             }
 395           /* Read nameservers to query.  */
 396           if (MATCH (parser->buffer, "nameserver"))
 397             {
 398               struct in_addr a;
 399
 400               cp = parser->buffer + sizeof ("nameserver") - 1;
 401               while (*cp == ' ' || *cp == '\t')
 402                 cp++;
 403
 404               /* Ignore trailing contents on the name server line.  */
 405               {
 406                 char *el;
 407                 if ((el = strpbrk (cp, " \t\n")) != NULL)
 408                   *el = '\0';
 409               }
 410
 411               struct sockaddr *sa;
 412               if ((*cp != '\0') && (*cp != '\n') && __inet_aton_exact (cp, &a))
 413                 {
 414                   sa = allocate_address_v4 (a, NAMESERVER_PORT);
 415                   if (sa == NULL)
 416                     return false;
 417                 }
 418               else
 419                 {
 420                   struct in6_addr a6;
 421                   char *el;
 422                   if ((el = strchr (cp, SCOPE_DELIMITER)) != NULL)
 423                     *el = '\0';
 424                   if ((*cp != '\0') && (__inet_pton (AF_INET6, cp, &a6) > 0))
 425                     {
 426                       struct sockaddr_in6 *sa6;
 427
 428                       sa6 = malloc (sizeof (*sa6));
 429                       if (sa6 == NULL)
 430                         return false;
 431
 432                       sa6->sin6_family = AF_INET6;
 433                       sa6->sin6_port = htons (NAMESERVER_PORT);
 434                       sa6->sin6_flowinfo = 0;
 435                       sa6->sin6_addr = a6;
 436
 437                       sa6->sin6_scope_id = 0;
 438                       if (__glibc_likely (el != NULL))
 439                         /* Ignore errors, for backwards
 440                            compatibility.  */
 441                         __inet6_scopeid_pton
 442                           (&a6, el + 1, &sa6->sin6_scope_id);
 443                       sa = (struct sockaddr *) sa6;
 444                     }
 445                   else
 446                     /* IPv6 address parse failure.  */
 447                     sa = NULL;
 448                 }
 449               if (sa != NULL)
 450                 {
 451                   const struct sockaddr **p = nameserver_list_emplace
 452                     (&parser->nameserver_list);
 453                   if (p != NULL)
 454                     *p = sa;
 455                   else
 456                     {
 457                       free (sa);
 458                       return false;
 459                     }
 460                 }
 461               continue;
 462             }
 463           if (MATCH (parser->buffer, "sortlist"))
 464             {
 465               struct in_addr a;
 466
 467               cp = parser->buffer + sizeof ("sortlist") - 1;
 468               while (true)
 469                 {
 470                   while (*cp == ' ' || *cp == '\t')
 471                     cp++;
 472                   if (*cp == '\0' || *cp == '\n' || *cp == ';')
 473                     break;
 474                   char *net = cp;
 475                   while (*cp && !is_sort_mask (*cp) && *cp != ';'
 476                          && isascii (*cp) && !isspace (*cp))
 477                     cp++;
 478                   char separator = *cp;
 479                   *cp = 0;
 480                   struct resolv_sortlist_entry e;
 481                   if (__inet_aton_exact (net, &a))
 482                     {
 483                       e.addr = a;
 484                       if (is_sort_mask (separator))
 485                         {
 486                           *cp++ = separator;
 487                           net = cp;
 488                           while (*cp && *cp != ';'
 489                                  && isascii (*cp) && !isspace (*cp))
 490                             cp++;
 491                           separator = *cp;
 492                           *cp = 0;
 493                           if (__inet_aton_exact (net, &a))
 494                             e.mask = a.s_addr;
 495                           else
 496                             e.mask = net_mask (e.addr);
 497                         }
 498                       else
 499                         e.mask = net_mask (e.addr);
 500                       sort_list_add (&parser->sort_list, e);
 501                     }
 502                   *cp = separator;
 503                 }
 504               continue;
 505             }
 506           if (MATCH (parser->buffer, "options"))
 507             {
 508               res_setoptions (parser, parser->buffer + sizeof ("options") - 1);
 509               continue;
 510             }
 511         }
 512     }
 513   if (__glibc_unlikely (nameserver_list_size (&parser->nameserver_list) == 0))
 514     {
 515       const struct sockaddr **p
 516         = nameserver_list_emplace (&parser->nameserver_list);
 517       if (p == NULL)
 518         return false;
 519       *p = allocate_address_v4 (__inet_makeaddr (IN_LOOPBACKNET, 1),
 520                                 NAMESERVER_PORT);
 521       if (*p == NULL)
 522         return false;
 523     }
 524
 525   if (search_list_size (&parser->search_list) == 0)
 526     {
 527       char *domain;
 528       if (!domain_from_hostname (&domain))
 529         return false;
 530       if (domain != NULL)
 531         {
 532           free (parser->search_list_store);
 533           parser->search_list_store = domain;
 534           search_list_add (&parser->search_list, domain);
 535         }
 536     }
 537
 538   if ((cp = getenv ("RES_OPTIONS")) != NULL)
 539     res_setoptions (parser, cp);
 540
 541   if (nameserver_list_has_failed (&parser->nameserver_list)
 542       || search_list_has_failed (&parser->search_list)
 543       || sort_list_has_failed (&parser->sort_list))
 544     {
 545       __set_errno (ENOMEM);
 546       return false;
 547     }
 548
 549   return true;
 550 }
 551
 552 struct resolv_conf *
 553 __resolv_conf_load (struct __res_state *preinit,
 554                     struct file_change_detection *change)
 555 {
 556   /* Ensure that /etc/hosts.conf has been loaded (once).  */
 557   _res_hconf_init ();
 558
 559   FILE *fp = fopen (_PATH_RESCONF, "rce");
 560   if (fp == NULL)
 561     switch (errno)
 562       {
 563       case EACCES:
 564       case EISDIR:
 565       case ELOOP:
 566       case ENOENT:
 567       case ENOTDIR:
 568       case EPERM:
 569         /* Ignore these errors.  They are persistent errors caused
 570            by file system contents.  */
 571         break;
 572       default:
 573         /* Other errors refer to resource allocation problems and
 574            need to be handled by the application.  */
 575         return NULL;
 576       }
 577
 578   struct resolv_conf_parser parser;
 579   resolv_conf_parser_init (&parser, preinit);
 580
 581   struct resolv_conf *conf = NULL;
 582   bool ok = res_vinit_1 (fp, &parser);
 583   if (ok && change != NULL)
 584     /* Update the file change information if the configuration was
 585        loaded successfully.  */
 586     ok = __file_change_detection_for_fp (change, fp);
 587
 588   if (ok)
 589     {
 590       parser.template.nameserver_list
 591         = nameserver_list_begin (&parser.nameserver_list);
 592       parser.template.nameserver_list_size
 593         = nameserver_list_size (&parser.nameserver_list);
 594       parser.template.search_list = search_list_begin (&parser.search_list);
 595       parser.template.search_list_size
 596         = search_list_size (&parser.search_list);
 597       parser.template.sort_list = sort_list_begin (&parser.sort_list);
 598       parser.template.sort_list_size = sort_list_size (&parser.sort_list);
 599       conf = __resolv_conf_allocate (&parser.template);
 600     }
 601   resolv_conf_parser_free (&parser);
 602
 603   if (fp != NULL)
 604     {
 605       int saved_errno = errno;
 606       fclose (fp);
 607       __set_errno (saved_errno);
 608     }
 609
 610   return conf;
 611 }
 612
 613 /* Set up default settings.  If the /etc/resolv.conf configuration
 614    file exist, the values there will have precedence.  Otherwise, the
 615    server address is set to INADDR_LOOPBACK and the default domain
 616    name comes from gethostname.  The RES_OPTIONS and LOCALDOMAIN
 617    environment variables can be used to override some settings.
 618    Return 0 if completes successfully, -1 on error.  */
 619 int
 620 __res_vinit (res_state statp, int preinit)
 621 {
 622   struct resolv_conf *conf;
 623   if (preinit && has_preinit_values (statp))
 624     /* For the preinit case, we cannot use the cached configuration
 625        because some settings could be different.  */
 626     conf = __resolv_conf_load (statp, NULL);
 627   else
 628     conf = __resolv_conf_get_current ();
 629   if (conf == NULL)
 630     return -1;
 631
 632   bool ok = __resolv_conf_attach (statp, conf);
 633   __resolv_conf_put (conf);
 634   if (ok)
 635     {
 636       if (preinit)
 637         statp->id = res_randomid ();
 638       return 0;
 639     }
 640   else
 641     return -1;
 642 }
 643
 644 static void
 645 res_setoptions (struct resolv_conf_parser *parser, const char *options)
 646 {
 647   const char *cp = options;
 648
 649   while (*cp)
 650     {
 651       /* Skip leading and inner runs of spaces.  */
 652       while (*cp == ' ' || *cp == '\t')
 653         cp++;
 654       /* Search for and process individual options.  */
 655       if (!strncmp (cp, "ndots:", sizeof ("ndots:") - 1))
 656         {
 657           int i = strtol (cp + sizeof ("ndots:") - 1, NULL, 10);
 658           if (i <= RES_MAXNDOTS)
 659             parser->template.ndots = i;
 660           else
 661             parser->template.ndots = RES_MAXNDOTS;
 662         }
 663       else if (!strncmp (cp, "timeout:", sizeof ("timeout:") - 1))
 664         {
 665           int i = strtol (cp + sizeof ("timeout:") - 1, NULL, 10);
 666           if (i <= RES_MAXRETRANS)
 667             parser->template.retrans = i;
 668           else
 669             parser->template.retrans = RES_MAXRETRANS;
 670         }
 671       else if (!strncmp (cp, "attempts:", sizeof ("attempts:") - 1))
 672         {
 673           int i = strtol (cp + sizeof ("attempts:") - 1, NULL, 10);
 674           if (i <= RES_MAXRETRY)
 675             parser->template.retry = i;
 676           else
 677             parser->template.retry = RES_MAXRETRY;
 678         }
 679       else
 680         {
 681           static const struct
 682           {
 683             char str[22];
 684             uint8_t len;
 685             uint8_t clear;
 686             unsigned long int flag;
 687           } options[] = {
 688 #define STRnLEN(str) str, sizeof (str) - 1
 689             { STRnLEN ("rotate"), 0, RES_ROTATE },
 690             { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
 691             { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
 692             { STRnLEN ("single-request"), 0, RES_SNGLKUP },
 693             { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
 694             { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
 695             { STRnLEN ("no-reload"), 0, RES_NORELOAD },
 696             { STRnLEN ("use-vc"), 0, RES_USEVC },
 697             { STRnLEN ("trust-ad"), 0, RES_TRUSTAD },
 698             { STRnLEN ("no-aaaa"), 0, RES_NOAAAA },
 699           };
 700 #define noptions (sizeof (options) / sizeof (options[0]))
 701           for (int i = 0; i < noptions; ++i)
 702             if (strncmp (cp, options[i].str, options[i].len) == 0)
 703               {
 704                 if (options[i].clear)
 705                   parser->template.options &= options[i].flag;
 706                 else
 707                   parser->template.options |= options[i].flag;
 708                 break;
 709               }
 710         }
 711       /* Skip to next run of spaces.  */
 712       while (*cp && *cp != ' ' && *cp != '\t')
 713         cp++;
 714     }
 715 }
 716
 717 static uint32_t
 718 net_mask (struct in_addr in)
 719 {
 720   uint32_t i = ntohl (in.s_addr);
 721
 722   if (IN_CLASSA (i))
 723     return htonl (IN_CLASSA_NET);
 724   else if (IN_CLASSB (i))
 725     return htonl (IN_CLASSB_NET);
 726   return htonl (IN_CLASSC_NET);
 727 }