resolv/res_init.c

   1 /*
   2  * Copyright (c) 1985, 1989, 1993
   3  *    The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  */
  49
  50 /*
  51  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
  52  *
  53  * Permission to use, copy, modify, and distribute this software for any
  54  * purpose with or without fee is hereby granted, provided that the above
  55  * copyright notice and this permission notice appear in all copies.
  56  *
  57  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
  58  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  59  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  60  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  61  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  62  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  63  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  64  * SOFTWARE.
  65  */
  66
  67 #if defined(LIBC_SCCS) && !defined(lint)
  68 static const char sccsid[] = "@(#)res_init.c    8.1 (Berkeley) 6/7/93";
  69 static const char rcsid[] = "$BINDId: res_init.c,v 8.16 2000/05/09 07:10:12 vixie Exp $";
  70 #endif /* LIBC_SCCS and not lint */
  71
  72 #include <ctype.h>
  73 #include <netdb.h>
  74 #include <resolv.h>
  75 #include <stdio.h>
  76 #include <stdio_ext.h>
  77 #include <stdlib.h>
  78 #include <string.h>
  79 #include <unistd.h>
  80 #include <arpa/inet.h>
  81 #include <arpa/nameser.h>
  82 #include <net/if.h>
  83 #include <netinet/in.h>
  84 #include <sys/param.h>
  85 #include <sys/socket.h>
  86 #include <sys/time.h>
  87 #include <sys/types.h>
  88
  89 #include <not-cancel.h>
  90
  91 /* Options.  Should all be left alone. */
  92 #define RESOLVSORT
  93 #define RFC1535
  94 /* #undef DEBUG */
  95
  96 static void res_setoptions (res_state, const char *, const char *)
  97      internal_function;
  98
  99 #ifdef RESOLVSORT
 100 static const char sort_mask_chars[] = "/&";
 101 #define ISSORTMASK(ch) (strchr(sort_mask_chars, ch) != NULL)
 102 static u_int32_t net_mask (struct in_addr) __THROW;
 103 #endif
 104
 105 #if !defined(isascii)   /* XXX - could be a function */
 106 # define isascii(c) (!(c & 0200))
 107 #endif
 108
 109 #ifdef _LIBC
 110 unsigned long long int __res_initstamp attribute_hidden;
 111 #endif
 112
 113 /*
 114  * Resolver state default settings.
 115  */
 116
 117 /*
 118  * Set up default settings.  If the configuration file exist, the values
 119  * there will have precedence.  Otherwise, the server address is set to
 120  * INADDR_ANY and the default domain name comes from the gethostname().
 121  *
 122  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 123  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 124  * since it was noted that INADDR_ANY actually meant ``the first interface
 125  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 126  * it had to be "up" in order for you to reach your own name server.  It
 127  * was later decided that since the recommended practice is to always
 128  * install local static routes through 127.0.0.1 for all your network
 129  * interfaces, that we could solve this problem without a code change.
 130  *
 131  * The configuration file should always be used, since it is the only way
 132  * to specify a default domain.  If you are running a server on your local
 133  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 134  * in the configuration file.
 135  *
 136  * Return 0 if completes successfully, -1 on error
 137  */
 138 int
 139 res_ninit(res_state statp) {
 140         extern int __res_vinit(res_state, int);
 141
 142         return (__res_vinit(statp, 0));
 143 }
 144 #ifdef _LIBC
 145 libc_hidden_def (__res_ninit)
 146 #endif
 147
 148 /* This function has to be reachable by res_data.c but not publically. */
 149 int
 150 __res_vinit(res_state statp, int preinit) {
 151         register FILE *fp;
 152         register char *cp, **pp;
 153         register int n;
 154         char buf[BUFSIZ];
 155         int nserv = 0;    /* number of nameserver records read from file */
 156 #ifdef _LIBC
 157         int nservall = 0; /* number of NS records read, nserv IPv4 only */
 158 #endif
 159         int haveenv = 0;
 160         int havesearch = 0;
 161 #ifdef RESOLVSORT
 162         int nsort = 0;
 163         char *net;
 164 #endif
 165 #ifndef RFC1535
 166         int dots;
 167 #endif
 168 #ifdef _LIBC
 169         statp->_u._ext.initstamp = __res_initstamp;
 170 #endif
 171
 172         if (!preinit) {
 173                 statp->retrans = RES_TIMEOUT;
 174                 statp->retry = RES_DFLRETRY;
 175                 statp->options = RES_DEFAULT;
 176                 statp->id = res_randomid();
 177         }
 178
 179 #ifdef USELOOPBACK
 180         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 181 #else
 182         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 183 #endif
 184         statp->nsaddr.sin_family = AF_INET;
 185         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 186         statp->nscount = 0;
 187         statp->ndots = 1;
 188         statp->pfcode = 0;
 189         statp->_vcsock = -1;
 190         statp->_flags = 0;
 191         statp->qhook = NULL;
 192         statp->rhook = NULL;
 193         statp->_u._ext.nsinit = 0;
 194         statp->_u._ext.nscount = 0;
 195 #ifdef _LIBC
 196         statp->_u._ext.nscount6 = 0;
 197         for (n = 0; n < MAXNS; n++) {
 198                 statp->_u._ext.nsaddrs[n] = NULL;
 199                 statp->_u._ext.nsmap[n] = MAXNS;
 200         }
 201 #endif
 202
 203         /* Allow user to override the local domain definition */
 204         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 205                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 206                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 207                 haveenv++;
 208
 209                 /*
 210                  * Set search list to be blank-separated strings
 211                  * from rest of env value.  Permits users of LOCALDOMAIN
 212                  * to still have a search list, and anyone to set the
 213                  * one that they want to use as an individual (even more
 214                  * important now that the rfc1535 stuff restricts searches)
 215                  */
 216                 cp = statp->defdname;
 217                 pp = statp->dnsrch;
 218                 *pp++ = cp;
 219                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 220                         if (*cp == '\n')        /* silly backwards compat */
 221                                 break;
 222                         else if (*cp == ' ' || *cp == '\t') {
 223                                 *cp = 0;
 224                                 n = 1;
 225                         } else if (n) {
 226                                 *pp++ = cp;
 227                                 n = 0;
 228                                 havesearch = 1;
 229                         }
 230                 }
 231                 /* null terminate last domain if there are excess */
 232                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 233                         cp++;
 234                 *cp = '\0';
 235                 *pp++ = 0;
 236         }
 237
 238 #define MATCH(line, name) \
 239         (!strncmp(line, name, sizeof(name) - 1) && \
 240         (line[sizeof(name) - 1] == ' ' || \
 241          line[sizeof(name) - 1] == '\t'))
 242
 243         if ((fp = fopen(_PATH_RESCONF, "rc")) != NULL) {
 244             /* No threads use this stream.  */
 245             __fsetlocking (fp, FSETLOCKING_BYCALLER);
 246             /* read the config file */
 247             while (fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 248                 /* skip comments */
 249                 if (*buf == ';' || *buf == '#')
 250                         continue;
 251                 /* read default domain name */
 252                 if (MATCH(buf, "domain")) {
 253                     if (haveenv)        /* skip if have from environ */
 254                             continue;
 255                     cp = buf + sizeof("domain") - 1;
 256                     while (*cp == ' ' || *cp == '\t')
 257                             cp++;
 258                     if ((*cp == '\0') || (*cp == '\n'))
 259                             continue;
 260                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 261                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 262                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 263                             *cp = '\0';
 264                     havesearch = 0;
 265                     continue;
 266                 }
 267                 /* set search list */
 268                 if (MATCH(buf, "search")) {
 269                     if (haveenv)        /* skip if have from environ */
 270                             continue;
 271                     cp = buf + sizeof("search") - 1;
 272                     while (*cp == ' ' || *cp == '\t')
 273                             cp++;
 274                     if ((*cp == '\0') || (*cp == '\n'))
 275                             continue;
 276                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 277                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 278                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 279                             *cp = '\0';
 280                     /*
 281                      * Set search list to be blank-separated strings
 282                      * on rest of line.
 283                      */
 284                     cp = statp->defdname;
 285                     pp = statp->dnsrch;
 286                     *pp++ = cp;
 287                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 288                             if (*cp == ' ' || *cp == '\t') {
 289                                     *cp = 0;
 290                                     n = 1;
 291                             } else if (n) {
 292                                     *pp++ = cp;
 293                                     n = 0;
 294                             }
 295                     }
 296                     /* null terminate last domain if there are excess */
 297                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 298                             cp++;
 299                     *cp = '\0';
 300                     *pp++ = 0;
 301                     havesearch = 1;
 302                     continue;
 303                 }
 304                 /* read nameservers to query */
 305 #ifdef _LIBC
 306                 if (MATCH(buf, "nameserver") && nservall < MAXNS) {
 307 #else
 308                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 309 #endif
 310                     struct in_addr a;
 311
 312                     cp = buf + sizeof("nameserver") - 1;
 313                     while (*cp == ' ' || *cp == '\t')
 314                         cp++;
 315                     if ((*cp != '\0') && (*cp != '\n')
 316                         && __inet_aton(cp, &a)) {
 317                         statp->nsaddr_list[nservall].sin_addr = a;
 318                         statp->nsaddr_list[nservall].sin_family = AF_INET;
 319                         statp->nsaddr_list[nservall].sin_port =
 320                                 htons(NAMESERVER_PORT);
 321                         nserv++;
 322 #ifdef _LIBC
 323                         nservall++;
 324                     } else {
 325                         struct in6_addr a6;
 326                         char *el;
 327
 328                         if ((el = strchr(cp, '\n')) != NULL)
 329                             *el = '\0';
 330                         if ((el = strchr(cp, SCOPE_DELIMITER)) != NULL)
 331                             *el = '\0';
 332                         if ((*cp != '\0') &&
 333                             (inet_pton(AF_INET6, cp, &a6) > 0)) {
 334                             struct sockaddr_in6 *sa6;
 335
 336                             sa6 = malloc(sizeof(*sa6));
 337                             if (sa6 != NULL) {
 338                                 sa6->sin6_family = AF_INET6;
 339                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 340                                 sa6->sin6_flowinfo = 0;
 341                                 sa6->sin6_addr = a6;
 342
 343                                 if (__builtin_expect (el == NULL, 1))
 344                                     sa6->sin6_scope_id = 0;
 345                                 else {
 346                                     int try_numericscope = 1;
 347                                     if (IN6_IS_ADDR_LINKLOCAL (&a6)
 348                                         || IN6_IS_ADDR_MC_LINKLOCAL (&a6)) {
 349                                         sa6->sin6_scope_id
 350                                           = if_nametoindex (el + 1);
 351                                         if (sa6->sin6_scope_id != 0)
 352                                             try_numericscope = 0;
 353                                     }
 354
 355                                     if (try_numericscope) {
 356                                         char *end;
 357                                         sa6->sin6_scope_id
 358                                           = (uint32_t) strtoul (el + 1, &end,
 359                                                                 10);
 360                                         if (*end != '\0')
 361                                             sa6->sin6_scope_id = 0;
 362                                     }
 363                                 }
 364
 365                                 statp->_u._ext.nsaddrs[nservall] = sa6;
 366                                 statp->_u._ext.nssocks[nservall] = -1;
 367                                 statp->_u._ext.nsmap[nservall] = MAXNS + 1;
 368                                 nservall++;
 369                             }
 370                         }
 371 #endif
 372                     }
 373                     continue;
 374                 }
 375 #ifdef RESOLVSORT
 376                 if (MATCH(buf, "sortlist")) {
 377                     struct in_addr a;
 378
 379                     cp = buf + sizeof("sortlist") - 1;
 380                     while (nsort < MAXRESOLVSORT) {
 381                         while (*cp == ' ' || *cp == '\t')
 382                             cp++;
 383                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 384                             break;
 385                         net = cp;
 386                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 387                                isascii(*cp) && !isspace(*cp))
 388                                 cp++;
 389                         n = *cp;
 390                         *cp = 0;
 391                         if (__inet_aton(net, &a)) {
 392                             statp->sort_list[nsort].addr = a;
 393                             if (ISSORTMASK(n)) {
 394                                 *cp++ = n;
 395                                 net = cp;
 396                                 while (*cp && *cp != ';' &&
 397                                         isascii(*cp) && !isspace(*cp))
 398                                     cp++;
 399                                 n = *cp;
 400                                 *cp = 0;
 401                                 if (__inet_aton(net, &a)) {
 402                                     statp->sort_list[nsort].mask = a.s_addr;
 403                                 } else {
 404                                     statp->sort_list[nsort].mask =
 405                                         net_mask(statp->sort_list[nsort].addr);
 406                                 }
 407                             } else {
 408                                 statp->sort_list[nsort].mask =
 409                                     net_mask(statp->sort_list[nsort].addr);
 410                             }
 411                             nsort++;
 412                         }
 413                         *cp = n;
 414                     }
 415                     continue;
 416                 }
 417 #endif
 418                 if (MATCH(buf, "options")) {
 419                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 420                     continue;
 421                 }
 422             }
 423             statp->nscount = nservall;
 424 #ifdef _LIBC
 425             if (nservall - nserv > 0) {
 426                 statp->_u._ext.nscount6 = nservall - nserv;
 427                 /* We try IPv6 servers again.  */
 428                 statp->ipv6_unavail = false;
 429             }
 430 #endif
 431 #ifdef RESOLVSORT
 432             statp->nsort = nsort;
 433 #endif
 434             (void) fclose(fp);
 435         }
 436         if (statp->defdname[0] == 0 &&
 437             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 438             (cp = strchr(buf, '.')) != NULL)
 439                 strcpy(statp->defdname, cp + 1);
 440
 441         /* find components of local domain that might be searched */
 442         if (havesearch == 0) {
 443                 pp = statp->dnsrch;
 444                 *pp++ = statp->defdname;
 445                 *pp = NULL;
 446
 447 #ifndef RFC1535
 448                 dots = 0;
 449                 for (cp = statp->defdname; *cp; cp++)
 450                         dots += (*cp == '.');
 451
 452                 cp = statp->defdname;
 453                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 454                         if (dots < LOCALDOMAINPARTS)
 455                                 break;
 456                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 457                         *pp++ = cp;
 458                         dots--;
 459                 }
 460                 *pp = NULL;
 461 #ifdef DEBUG
 462                 if (statp->options & RES_DEBUG) {
 463                         printf(";; res_init()... default dnsrch list:\n");
 464                         for (pp = statp->dnsrch; *pp; pp++)
 465                                 printf(";;\t%s\n", *pp);
 466                         printf(";;\t..END..\n");
 467                 }
 468 #endif
 469 #endif /* !RFC1535 */
 470         }
 471
 472         if ((cp = getenv("RES_OPTIONS")) != NULL)
 473                 res_setoptions(statp, cp, "env");
 474         statp->options |= RES_INIT;
 475         return (0);
 476 }
 477
 478 static void
 479 internal_function
 480 res_setoptions(res_state statp, const char *options, const char *source) {
 481         const char *cp = options;
 482         int i;
 483
 484 #ifdef DEBUG
 485         if (statp->options & RES_DEBUG)
 486                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 487                        options, source);
 488 #endif
 489         while (*cp) {
 490                 /* skip leading and inner runs of spaces */
 491                 while (*cp == ' ' || *cp == '\t')
 492                         cp++;
 493                 /* search for and process individual options */
 494                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 495                         i = atoi(cp + sizeof("ndots:") - 1);
 496                         if (i <= RES_MAXNDOTS)
 497                                 statp->ndots = i;
 498                         else
 499                                 statp->ndots = RES_MAXNDOTS;
 500 #ifdef DEBUG
 501                         if (statp->options & RES_DEBUG)
 502                                 printf(";;\tndots=%d\n", statp->ndots);
 503 #endif
 504                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 505                         i = atoi(cp + sizeof("timeout:") - 1);
 506                         if (i <= RES_MAXRETRANS)
 507                                 statp->retrans = i;
 508                         else
 509                                 statp->retrans = RES_MAXRETRANS;
 510                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 511                         i = atoi(cp + sizeof("attempts:") - 1);
 512                         if (i <= RES_MAXRETRY)
 513                                 statp->retry = i;
 514                         else
 515                                 statp->retry = RES_MAXRETRY;
 516                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 517 #ifdef DEBUG
 518                         if (!(statp->options & RES_DEBUG)) {
 519                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 520                                        options, source);
 521                                 statp->options |= RES_DEBUG;
 522                         }
 523                         printf(";;\tdebug\n");
 524 #endif
 525                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 526                         statp->options |= RES_USE_INET6;
 527                 } else if (!strncmp(cp, "ip6-bytestring",
 528                                     sizeof("ip6-bytestring") - 1)) {
 529                         statp->options |= RES_USEBSTRING;
 530                 } else if (!strncmp(cp, "no-ip6-dotint",
 531                                     sizeof("no-ip6-dotint") - 1)) {
 532                         statp->options |= RES_NOIP6DOTINT;
 533                 } else if (!strncmp(cp, "ip6-dotint",
 534                                     sizeof("ip6-dotint") - 1)) {
 535                         statp->options &= ~RES_NOIP6DOTINT;
 536                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 537                         statp->options |= RES_ROTATE;
 538                 } else if (!strncmp(cp, "no-check-names",
 539                                     sizeof("no-check-names") - 1)) {
 540                         statp->options |= RES_NOCHECKNAME;
 541                 } else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
 542                         statp->options |= RES_USE_EDNS0;
 543                 } else if (!strncmp(cp, "single-request-reopen",
 544                                     sizeof("single-request-reopen") - 1)) {
 545                         statp->options |= RES_SNGLKUPREOP;
 546                 } else if (!strncmp(cp, "single-request",
 547                                     sizeof("single-request") - 1)) {
 548                         statp->options |= RES_SNGLKUP;
 549                 } else {
 550                         /* XXX - print a warning here? */
 551                 }
 552                 /* skip to next run of spaces */
 553                 while (*cp && *cp != ' ' && *cp != '\t')
 554                         cp++;
 555         }
 556 }
 557
 558 #ifdef RESOLVSORT
 559 /* XXX - should really support CIDR which means explicit masks always. */
 560 static u_int32_t
 561 net_mask(in)            /* XXX - should really use system's version of this */
 562         struct in_addr in;
 563 {
 564         register u_int32_t i = ntohl(in.s_addr);
 565
 566         if (IN_CLASSA(i))
 567                 return (htonl(IN_CLASSA_NET));
 568         else if (IN_CLASSB(i))
 569                 return (htonl(IN_CLASSB_NET));
 570         return (htonl(IN_CLASSC_NET));
 571 }
 572 #endif
 573
 574 u_int
 575 res_randomid(void) {
 576         return 0xffff & __getpid();
 577 }
 578 #ifdef _LIBC
 579 libc_hidden_def (__res_randomid)
 580 #endif
 581
 582
 583 /*
 584  * This routine is for closing the socket if a virtual circuit is used and
 585  * the program wants to close it.  This provides support for endhostent()
 586  * which expects to close the socket.
 587  *
 588  * This routine is not expected to be user visible.
 589  */
 590 void
 591 __res_iclose(res_state statp, bool free_addr) {
 592         int ns;
 593
 594         if (statp->_vcsock >= 0) {
 595                 close_not_cancel_no_status(statp->_vcsock);
 596                 statp->_vcsock = -1;
 597                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 598         }
 599 #ifdef _LIBC
 600         for (ns = 0; ns < MAXNS; ns++)
 601 #else
 602         for (ns = 0; ns < statp->_u._ext.nscount; ns++)
 603 #endif
 604                 if (statp->_u._ext.nsaddrs[ns]) {
 605                         if (statp->_u._ext.nssocks[ns] != -1) {
 606                                 close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
 607                                 statp->_u._ext.nssocks[ns] = -1;
 608                         }
 609                         if (free_addr) {
 610                                 free (statp->_u._ext.nsaddrs[ns]);
 611                                 statp->_u._ext.nsaddrs[ns] = NULL;
 612                         }
 613                 }
 614         statp->_u._ext.nsinit = 0;
 615 }
 616 libc_hidden_def (__res_iclose)
 617
 618 void
 619 res_nclose(res_state statp)
 620 {
 621   __res_iclose (statp, true);
 622 }
 623 #ifdef _LIBC
 624 libc_hidden_def (__res_nclose)
 625 #endif
 626
 627 #ifdef _LIBC
 628 # ifdef _LIBC_REENTRANT
 629 /* This is called when a thread is exiting to free resources held in _res.  */
 630 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
 631 res_thread_freeres (void)
 632 {
 633   if (_res.nscount == 0)
 634     /* Never called res_ninit.  */
 635     return;
 636
 637   __res_iclose (&_res, true);           /* Close any VC sockets.  */
 638
 639   /* Make sure we do a full re-initialization the next time.  */
 640   _res.options = 0;
 641 }
 642 text_set_element (__libc_thread_subfreeres, res_thread_freeres);
 643 text_set_element (__libc_subfreeres, res_thread_freeres);
 644 # endif
 645 #endif