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 <stdint.h>
  81 #include <arpa/inet.h>
  82 #include <arpa/nameser.h>
  83 #include <net/if.h>
  84 #include <netinet/in.h>
  85 #include <sys/param.h>
  86 #include <sys/socket.h>
  87 #include <sys/time.h>
  88 #include <sys/types.h>
  89
  90 #include <not-cancel.h>
  91
  92 /* Options.  Should all be left alone. */
  93 #define RESOLVSORT
  94 #define RFC1535
  95 /* #undef DEBUG */
  96
  97 static void res_setoptions (res_state, const char *, const char *)
  98      internal_function;
  99
 100 #ifdef RESOLVSORT
 101 static const char sort_mask_chars[] = "/&";
 102 #define ISSORTMASK(ch) (strchr(sort_mask_chars, ch) != NULL)
 103 static u_int32_t net_mask (struct in_addr) __THROW;
 104 #endif
 105
 106 #if !defined(isascii)   /* XXX - could be a function */
 107 # define isascii(c) (!(c & 0200))
 108 #endif
 109
 110 #ifdef _LIBC
 111 unsigned long long int __res_initstamp attribute_hidden;
 112 #endif
 113
 114 /*
 115  * Resolver state default settings.
 116  */
 117
 118 /*
 119  * Set up default settings.  If the configuration file exist, the values
 120  * there will have precedence.  Otherwise, the server address is set to
 121  * INADDR_LOOPBACK and the default domain name comes from gethostname.
 122  *
 123  * Return 0 if completes successfully, -1 on error
 124  */
 125 int
 126 res_ninit(res_state statp) {
 127         extern int __res_vinit(res_state, int);
 128
 129         return (__res_vinit(statp, 0));
 130 }
 131 #ifdef _LIBC
 132 libc_hidden_def (__res_ninit)
 133 #endif
 134
 135 /* This function has to be reachable by res_data.c but not publically. */
 136 int
 137 __res_vinit(res_state statp, int preinit) {
 138         FILE *fp;
 139         char *cp, **pp;
 140         int n;
 141         char buf[BUFSIZ];
 142         int nserv = 0;    /* number of nameservers read from file */
 143         int have_serv6 = 0;
 144         int haveenv = 0;
 145         int havesearch = 0;
 146 #ifdef RESOLVSORT
 147         int nsort = 0;
 148         char *net;
 149 #endif
 150 #ifndef RFC1535
 151         int dots;
 152 #endif
 153 #ifdef _LIBC
 154         statp->_u._ext.initstamp = __res_initstamp;
 155 #endif
 156
 157         if (!preinit) {
 158                 statp->retrans = RES_TIMEOUT;
 159                 statp->retry = RES_DFLRETRY;
 160                 statp->options = RES_DEFAULT;
 161                 statp->id = res_randomid();
 162         }
 163
 164         statp->nscount = 0;
 165         statp->defdname[0] = '\0';
 166         statp->ndots = 1;
 167         statp->pfcode = 0;
 168         statp->_vcsock = -1;
 169         statp->_flags = 0;
 170         statp->qhook = NULL;
 171         statp->rhook = NULL;
 172         statp->_u._ext.nscount = 0;
 173         for (n = 0; n < MAXNS; n++)
 174             statp->_u._ext.nsaddrs[n] = NULL;
 175
 176         /* Allow user to override the local domain definition */
 177         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 178                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 179                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 180                 haveenv++;
 181
 182                 /*
 183                  * Set search list to be blank-separated strings
 184                  * from rest of env value.  Permits users of LOCALDOMAIN
 185                  * to still have a search list, and anyone to set the
 186                  * one that they want to use as an individual (even more
 187                  * important now that the rfc1535 stuff restricts searches)
 188                  */
 189                 cp = statp->defdname;
 190                 pp = statp->dnsrch;
 191                 *pp++ = cp;
 192                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 193                         if (*cp == '\n')        /* silly backwards compat */
 194                                 break;
 195                         else if (*cp == ' ' || *cp == '\t') {
 196                                 *cp = 0;
 197                                 n = 1;
 198                         } else if (n) {
 199                                 *pp++ = cp;
 200                                 n = 0;
 201                                 havesearch = 1;
 202                         }
 203                 }
 204                 /* null terminate last domain if there are excess */
 205                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 206                         cp++;
 207                 *cp = '\0';
 208                 *pp++ = 0;
 209         }
 210
 211 #define MATCH(line, name) \
 212         (!strncmp(line, name, sizeof(name) - 1) && \
 213         (line[sizeof(name) - 1] == ' ' || \
 214          line[sizeof(name) - 1] == '\t'))
 215
 216         if ((fp = fopen(_PATH_RESCONF, "rce")) != NULL) {
 217             /* No threads use this stream.  */
 218             __fsetlocking (fp, FSETLOCKING_BYCALLER);
 219             /* read the config file */
 220             while (__fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 221                 /* skip comments */
 222                 if (*buf == ';' || *buf == '#')
 223                         continue;
 224                 /* read default domain name */
 225                 if (MATCH(buf, "domain")) {
 226                     if (haveenv)        /* skip if have from environ */
 227                             continue;
 228                     cp = buf + sizeof("domain") - 1;
 229                     while (*cp == ' ' || *cp == '\t')
 230                             cp++;
 231                     if ((*cp == '\0') || (*cp == '\n'))
 232                             continue;
 233                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 234                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 235                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 236                             *cp = '\0';
 237                     havesearch = 0;
 238                     continue;
 239                 }
 240                 /* set search list */
 241                 if (MATCH(buf, "search")) {
 242                     if (haveenv)        /* skip if have from environ */
 243                             continue;
 244                     cp = buf + sizeof("search") - 1;
 245                     while (*cp == ' ' || *cp == '\t')
 246                             cp++;
 247                     if ((*cp == '\0') || (*cp == '\n'))
 248                             continue;
 249                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 250                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 251                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 252                             *cp = '\0';
 253                     /*
 254                      * Set search list to be blank-separated strings
 255                      * on rest of line.
 256                      */
 257                     cp = statp->defdname;
 258                     pp = statp->dnsrch;
 259                     *pp++ = cp;
 260                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 261                             if (*cp == ' ' || *cp == '\t') {
 262                                     *cp = 0;
 263                                     n = 1;
 264                             } else if (n) {
 265                                     *pp++ = cp;
 266                                     n = 0;
 267                             }
 268                     }
 269                     /* null terminate last domain if there are excess */
 270                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 271                             cp++;
 272                     *cp = '\0';
 273                     *pp++ = 0;
 274                     havesearch = 1;
 275                     continue;
 276                 }
 277                 /* read nameservers to query */
 278                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 279                     struct in_addr a;
 280
 281                     cp = buf + sizeof("nameserver") - 1;
 282                     while (*cp == ' ' || *cp == '\t')
 283                         cp++;
 284                     if ((*cp != '\0') && (*cp != '\n')
 285                         && __inet_aton(cp, &a)) {
 286                         statp->nsaddr_list[nserv].sin_addr = a;
 287                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 288                         statp->nsaddr_list[nserv].sin_port =
 289                                 htons(NAMESERVER_PORT);
 290                         nserv++;
 291 #ifdef _LIBC
 292                     } else {
 293                         struct in6_addr a6;
 294                         char *el;
 295
 296                         if ((el = strpbrk(cp, " \t\n")) != NULL)
 297                             *el = '\0';
 298                         if ((el = strchr(cp, SCOPE_DELIMITER)) != NULL)
 299                             *el = '\0';
 300                         if ((*cp != '\0') &&
 301                             (__inet_pton(AF_INET6, cp, &a6) > 0)) {
 302                             struct sockaddr_in6 *sa6;
 303
 304                             sa6 = malloc(sizeof(*sa6));
 305                             if (sa6 != NULL) {
 306                                 sa6->sin6_family = AF_INET6;
 307                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 308                                 sa6->sin6_flowinfo = 0;
 309                                 sa6->sin6_addr = a6;
 310
 311                                 if (__glibc_likely (el == NULL))
 312                                     sa6->sin6_scope_id = 0;
 313                                 else {
 314                                     int try_numericscope = 1;
 315                                     if (IN6_IS_ADDR_LINKLOCAL (&a6)
 316                                         || IN6_IS_ADDR_MC_LINKLOCAL (&a6)) {
 317                                         sa6->sin6_scope_id
 318                                           = __if_nametoindex (el + 1);
 319                                         if (sa6->sin6_scope_id != 0)
 320                                             try_numericscope = 0;
 321                                     }
 322
 323                                     if (try_numericscope) {
 324                                         char *end;
 325                                         sa6->sin6_scope_id
 326                                           = (uint32_t) strtoul (el + 1, &end,
 327                                                                 10);
 328                                         if (*end != '\0')
 329                                             sa6->sin6_scope_id = 0;
 330                                     }
 331                                 }
 332
 333                                 statp->nsaddr_list[nserv].sin_family = 0;
 334                                 statp->_u._ext.nsaddrs[nserv] = sa6;
 335                                 statp->_u._ext.nssocks[nserv] = -1;
 336                                 have_serv6 = 1;
 337                                 nserv++;
 338                             }
 339                         }
 340 #endif
 341                     }
 342                     continue;
 343                 }
 344 #ifdef RESOLVSORT
 345                 if (MATCH(buf, "sortlist")) {
 346                     struct in_addr a;
 347
 348                     cp = buf + sizeof("sortlist") - 1;
 349                     while (nsort < MAXRESOLVSORT) {
 350                         while (*cp == ' ' || *cp == '\t')
 351                             cp++;
 352                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 353                             break;
 354                         net = cp;
 355                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 356                                isascii(*cp) && !isspace(*cp))
 357                                 cp++;
 358                         n = *cp;
 359                         *cp = 0;
 360                         if (__inet_aton(net, &a)) {
 361                             statp->sort_list[nsort].addr = a;
 362                             if (ISSORTMASK(n)) {
 363                                 *cp++ = n;
 364                                 net = cp;
 365                                 while (*cp && *cp != ';' &&
 366                                         isascii(*cp) && !isspace(*cp))
 367                                     cp++;
 368                                 n = *cp;
 369                                 *cp = 0;
 370                                 if (__inet_aton(net, &a)) {
 371                                     statp->sort_list[nsort].mask = a.s_addr;
 372                                 } else {
 373                                     statp->sort_list[nsort].mask =
 374                                         net_mask(statp->sort_list[nsort].addr);
 375                                 }
 376                             } else {
 377                                 statp->sort_list[nsort].mask =
 378                                     net_mask(statp->sort_list[nsort].addr);
 379                             }
 380                             nsort++;
 381                         }
 382                         *cp = n;
 383                     }
 384                     continue;
 385                 }
 386 #endif
 387                 if (MATCH(buf, "options")) {
 388                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 389                     continue;
 390                 }
 391             }
 392             statp->nscount = nserv;
 393 #ifdef _LIBC
 394             if (have_serv6) {
 395                 /* We try IPv6 servers again.  */
 396                 statp->ipv6_unavail = false;
 397             }
 398 #endif
 399 #ifdef RESOLVSORT
 400             statp->nsort = nsort;
 401 #endif
 402             (void) fclose(fp);
 403         }
 404         if (__builtin_expect(statp->nscount == 0, 0)) {
 405             statp->nsaddr.sin_addr = __inet_makeaddr(IN_LOOPBACKNET, 1);
 406             statp->nsaddr.sin_family = AF_INET;
 407             statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 408             statp->nscount = 1;
 409         }
 410         if (statp->defdname[0] == 0 &&
 411             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 412             (cp = strchr(buf, '.')) != NULL)
 413                 strcpy(statp->defdname, cp + 1);
 414
 415         /* find components of local domain that might be searched */
 416         if (havesearch == 0) {
 417                 pp = statp->dnsrch;
 418                 *pp++ = statp->defdname;
 419                 *pp = NULL;
 420
 421 #ifndef RFC1535
 422                 dots = 0;
 423                 for (cp = statp->defdname; *cp; cp++)
 424                         dots += (*cp == '.');
 425
 426                 cp = statp->defdname;
 427                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 428                         if (dots < LOCALDOMAINPARTS)
 429                                 break;
 430                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 431                         *pp++ = cp;
 432                         dots--;
 433                 }
 434                 *pp = NULL;
 435 #ifdef DEBUG
 436                 if (statp->options & RES_DEBUG) {
 437                         printf(";; res_init()... default dnsrch list:\n");
 438                         for (pp = statp->dnsrch; *pp; pp++)
 439                                 printf(";;\t%s\n", *pp);
 440                         printf(";;\t..END..\n");
 441                 }
 442 #endif
 443 #endif /* !RFC1535 */
 444         }
 445
 446         if ((cp = getenv("RES_OPTIONS")) != NULL)
 447                 res_setoptions(statp, cp, "env");
 448         statp->options |= RES_INIT;
 449         return (0);
 450 }
 451
 452 static void
 453 internal_function
 454 res_setoptions(res_state statp, const char *options, const char *source) {
 455         const char *cp = options;
 456         int i;
 457
 458 #ifdef DEBUG
 459         if (statp->options & RES_DEBUG)
 460                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 461                        options, source);
 462 #endif
 463         while (*cp) {
 464                 /* skip leading and inner runs of spaces */
 465                 while (*cp == ' ' || *cp == '\t')
 466                         cp++;
 467                 /* search for and process individual options */
 468                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 469                         i = atoi(cp + sizeof("ndots:") - 1);
 470                         if (i <= RES_MAXNDOTS)
 471                                 statp->ndots = i;
 472                         else
 473                                 statp->ndots = RES_MAXNDOTS;
 474 #ifdef DEBUG
 475                         if (statp->options & RES_DEBUG)
 476                                 printf(";;\tndots=%d\n", statp->ndots);
 477 #endif
 478                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 479                         i = atoi(cp + sizeof("timeout:") - 1);
 480                         if (i <= RES_MAXRETRANS)
 481                                 statp->retrans = i;
 482                         else
 483                                 statp->retrans = RES_MAXRETRANS;
 484                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 485                         i = atoi(cp + sizeof("attempts:") - 1);
 486                         if (i <= RES_MAXRETRY)
 487                                 statp->retry = i;
 488                         else
 489                                 statp->retry = RES_MAXRETRY;
 490                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 491 #ifdef DEBUG
 492                         if (!(statp->options & RES_DEBUG)) {
 493                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 494                                        options, source);
 495                                 statp->options |= RES_DEBUG;
 496                         }
 497                         printf(";;\tdebug\n");
 498 #endif
 499                 } else {
 500                   static const struct
 501                   {
 502                     char str[22];
 503                     uint8_t len;
 504                     uint8_t clear;
 505                     unsigned long int flag;
 506                   } options[] = {
 507 #define STRnLEN(str) str, sizeof (str) - 1
 508                     { STRnLEN ("inet6"), 0, RES_USE_INET6 },
 509                     { STRnLEN ("ip6-bytestring"), 0, RES_USEBSTRING },
 510                     { STRnLEN ("no-ip6-dotint"), 0, RES_NOIP6DOTINT },
 511                     { STRnLEN ("ip6-dotint"), 1, ~RES_NOIP6DOTINT },
 512                     { STRnLEN ("rotate"), 0, RES_ROTATE },
 513                     { STRnLEN ("no-check-names"), 0, RES_NOCHECKNAME },
 514                     { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
 515                     { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
 516                     { STRnLEN ("single-request"), 0, RES_SNGLKUP },
 517                     { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
 518                     { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
 519                     { STRnLEN ("use-vc"), 0, RES_USEVC }
 520                   };
 521 #define noptions (sizeof (options) / sizeof (options[0]))
 522                   int i;
 523                   for (i = 0; i < noptions; ++i)
 524                     if (strncmp (cp, options[i].str, options[i].len) == 0)
 525                       {
 526                         if (options[i].clear)
 527                           statp->options &= options[i].flag;
 528                         else
 529                           statp->options |= options[i].flag;
 530                         break;
 531                       }
 532                   if (i == noptions) {
 533                     /* XXX - print a warning here? */
 534                   }
 535                 }
 536                 /* skip to next run of spaces */
 537                 while (*cp && *cp != ' ' && *cp != '\t')
 538                         cp++;
 539         }
 540 }
 541
 542 #ifdef RESOLVSORT
 543 /* XXX - should really support CIDR which means explicit masks always. */
 544 /* XXX - should really use system's version of this */
 545 static u_int32_t
 546 net_mask (struct in_addr in)
 547 {
 548         u_int32_t i = ntohl(in.s_addr);
 549
 550         if (IN_CLASSA(i))
 551                 return (htonl(IN_CLASSA_NET));
 552         else if (IN_CLASSB(i))
 553                 return (htonl(IN_CLASSB_NET));
 554         return (htonl(IN_CLASSC_NET));
 555 }
 556 #endif
 557
 558 u_int
 559 res_randomid(void) {
 560         return 0xffff & __getpid();
 561 }
 562 #ifdef _LIBC
 563 libc_hidden_def (__res_randomid)
 564 #endif
 565
 566
 567 /*
 568  * This routine is for closing the socket if a virtual circuit is used and
 569  * the program wants to close it.  This provides support for endhostent()
 570  * which expects to close the socket.
 571  *
 572  * This routine is not expected to be user visible.
 573  */
 574 void
 575 __res_iclose(res_state statp, bool free_addr) {
 576         int ns;
 577
 578         if (statp->_vcsock >= 0) {
 579                 close_not_cancel_no_status(statp->_vcsock);
 580                 statp->_vcsock = -1;
 581                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 582         }
 583         for (ns = 0; ns < statp->nscount; ns++)
 584                 if (statp->_u._ext.nsaddrs[ns]) {
 585                         if (statp->_u._ext.nssocks[ns] != -1) {
 586                                 close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
 587                                 statp->_u._ext.nssocks[ns] = -1;
 588                         }
 589                         if (free_addr) {
 590                                 free (statp->_u._ext.nsaddrs[ns]);
 591                                 statp->_u._ext.nsaddrs[ns] = NULL;
 592                         }
 593                 }
 594 }
 595 libc_hidden_def (__res_iclose)
 596
 597 void
 598 res_nclose(res_state statp)
 599 {
 600   __res_iclose (statp, true);
 601 }
 602 #ifdef _LIBC
 603 libc_hidden_def (__res_nclose)
 604 #endif
 605
 606 #ifdef _LIBC
 607 # ifdef _LIBC_REENTRANT
 608 /* This is called when a thread is exiting to free resources held in _res.  */
 609 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
 610 res_thread_freeres (void)
 611 {
 612   if (_res.nscount == 0)
 613     /* Never called res_ninit.  */
 614     return;
 615
 616   __res_iclose (&_res, true);           /* Close any VC sockets.  */
 617
 618   /* Make sure we do a full re-initialization the next time.  */
 619   _res.options = 0;
 620 }
 621 text_set_element (__libc_thread_subfreeres, res_thread_freeres);
 622 text_set_element (__libc_subfreeres, res_thread_freeres);
 623 # endif
 624 #endif