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 <sys/types.h>
  73 #include <sys/param.h>
  74 #include <sys/socket.h>
  75 #include <sys/time.h>
  76
  77 #include <netinet/in.h>
  78 #include <arpa/inet.h>
  79 #include <arpa/nameser.h>
  80
  81 #include <ctype.h>
  82 #include <resolv.h>
  83 #include <stdio.h>
  84 #include <stdio_ext.h>
  85 #include <stdlib.h>
  86 #include <string.h>
  87 #include <unistd.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 __P((struct in_addr));
 103 #endif
 104
 105 #if !defined(isascii)   /* XXX - could be a function */
 106 # define isascii(c) (!(c & 0200))
 107 #endif
 108
 109 /*
 110  * Resolver state default settings.
 111  */
 112
 113 /*
 114  * Set up default settings.  If the configuration file exist, the values
 115  * there will have precedence.  Otherwise, the server address is set to
 116  * INADDR_ANY and the default domain name comes from the gethostname().
 117  *
 118  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 119  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 120  * since it was noted that INADDR_ANY actually meant ``the first interface
 121  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 122  * it had to be "up" in order for you to reach your own name server.  It
 123  * was later decided that since the recommended practice is to always
 124  * install local static routes through 127.0.0.1 for all your network
 125  * interfaces, that we could solve this problem without a code change.
 126  *
 127  * The configuration file should always be used, since it is the only way
 128  * to specify a default domain.  If you are running a server on your local
 129  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 130  * in the configuration file.
 131  *
 132  * Return 0 if completes successfully, -1 on error
 133  */
 134 int
 135 res_ninit(res_state statp) {
 136         extern int __res_vinit(res_state, int);
 137
 138         return (__res_vinit(statp, 0));
 139 }
 140 #ifdef _LIBC
 141 libc_hidden_def (__res_ninit)
 142 #endif
 143
 144 /* This function has to be reachable by res_data.c but not publically. */
 145 int
 146 __res_vinit(res_state statp, int preinit) {
 147         register FILE *fp;
 148         register char *cp, **pp;
 149         register int n;
 150         char buf[BUFSIZ];
 151         int nserv = 0;    /* number of nameserver records read from file */
 152 #ifdef _LIBC
 153         int nservall = 0; /* number of NS records read, nserv IPv4 only */
 154 #endif
 155         int haveenv = 0;
 156         int havesearch = 0;
 157 #ifdef RESOLVSORT
 158         int nsort = 0;
 159         char *net;
 160 #endif
 161 #ifndef RFC1535
 162         int dots;
 163 #endif
 164
 165         if (!preinit) {
 166                 statp->retrans = RES_TIMEOUT;
 167                 statp->retry = RES_DFLRETRY;
 168                 statp->options = RES_DEFAULT;
 169                 statp->id = res_randomid();
 170         }
 171
 172 #ifdef USELOOPBACK
 173         statp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 174 #else
 175         statp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 176 #endif
 177         statp->nsaddr.sin_family = AF_INET;
 178         statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
 179         statp->nscount = 1;
 180         statp->ndots = 1;
 181         statp->pfcode = 0;
 182         statp->_vcsock = -1;
 183         statp->_flags = 0;
 184         statp->qhook = NULL;
 185         statp->rhook = NULL;
 186         statp->_u._ext.nsinit = 0;
 187         statp->_u._ext.nscount = 0;
 188 #ifdef _LIBC
 189         statp->_u._ext.nscount6 = 0;
 190         for (n = 0; n < MAXNS; n++) {
 191                 statp->_u._ext.nsaddrs[n] = NULL;
 192                 statp->_u._ext.nsmap[n] = MAXNS;
 193         }
 194 #endif
 195
 196         /* Allow user to override the local domain definition */
 197         if ((cp = getenv("LOCALDOMAIN")) != NULL) {
 198                 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 199                 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 200                 haveenv++;
 201
 202                 /*
 203                  * Set search list to be blank-separated strings
 204                  * from rest of env value.  Permits users of LOCALDOMAIN
 205                  * to still have a search list, and anyone to set the
 206                  * one that they want to use as an individual (even more
 207                  * important now that the rfc1535 stuff restricts searches)
 208                  */
 209                 cp = statp->defdname;
 210                 pp = statp->dnsrch;
 211                 *pp++ = cp;
 212                 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 213                         if (*cp == '\n')        /* silly backwards compat */
 214                                 break;
 215                         else if (*cp == ' ' || *cp == '\t') {
 216                                 *cp = 0;
 217                                 n = 1;
 218                         } else if (n) {
 219                                 *pp++ = cp;
 220                                 n = 0;
 221                                 havesearch = 1;
 222                         }
 223                 }
 224                 /* null terminate last domain if there are excess */
 225                 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 226                         cp++;
 227                 *cp = '\0';
 228                 *pp++ = 0;
 229         }
 230
 231 #define MATCH(line, name) \
 232         (!strncmp(line, name, sizeof(name) - 1) && \
 233         (line[sizeof(name) - 1] == ' ' || \
 234          line[sizeof(name) - 1] == '\t'))
 235
 236         if ((fp = fopen(_PATH_RESCONF, "rc")) != NULL) {
 237                 /* No threads use this stream.  */
 238                 __fsetlocking (fp, FSETLOCKING_BYCALLER);
 239             /* read the config file */
 240             while (fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
 241                 /* skip comments */
 242                 if (*buf == ';' || *buf == '#')
 243                         continue;
 244                 /* read default domain name */
 245                 if (MATCH(buf, "domain")) {
 246                     if (haveenv)        /* skip if have from environ */
 247                             continue;
 248                     cp = buf + sizeof("domain") - 1;
 249                     while (*cp == ' ' || *cp == '\t')
 250                             cp++;
 251                     if ((*cp == '\0') || (*cp == '\n'))
 252                             continue;
 253                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 254                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 255                     if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
 256                             *cp = '\0';
 257                     havesearch = 0;
 258                     continue;
 259                 }
 260                 /* set search list */
 261                 if (MATCH(buf, "search")) {
 262                     if (haveenv)        /* skip if have from environ */
 263                             continue;
 264                     cp = buf + sizeof("search") - 1;
 265                     while (*cp == ' ' || *cp == '\t')
 266                             cp++;
 267                     if ((*cp == '\0') || (*cp == '\n'))
 268                             continue;
 269                     strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
 270                     statp->defdname[sizeof(statp->defdname) - 1] = '\0';
 271                     if ((cp = strchr(statp->defdname, '\n')) != NULL)
 272                             *cp = '\0';
 273                     /*
 274                      * Set search list to be blank-separated strings
 275                      * on rest of line.
 276                      */
 277                     cp = statp->defdname;
 278                     pp = statp->dnsrch;
 279                     *pp++ = cp;
 280                     for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
 281                             if (*cp == ' ' || *cp == '\t') {
 282                                     *cp = 0;
 283                                     n = 1;
 284                             } else if (n) {
 285                                     *pp++ = cp;
 286                                     n = 0;
 287                             }
 288                     }
 289                     /* null terminate last domain if there are excess */
 290                     while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 291                             cp++;
 292                     *cp = '\0';
 293                     *pp++ = 0;
 294                     havesearch = 1;
 295                     continue;
 296                 }
 297                 /* read nameservers to query */
 298 #ifdef _LIBC
 299                 if (MATCH(buf, "nameserver") && nservall < MAXNS) {
 300 #else
 301                 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
 302 #endif
 303                     struct in_addr a;
 304
 305                     cp = buf + sizeof("nameserver") - 1;
 306                     while (*cp == ' ' || *cp == '\t')
 307                         cp++;
 308                     if ((*cp != '\0') && (*cp != '\n')
 309                         && __inet_aton(cp, &a)) {
 310                         statp->nsaddr_list[nserv].sin_addr = a;
 311                         statp->nsaddr_list[nserv].sin_family = AF_INET;
 312                         statp->nsaddr_list[nserv].sin_port =
 313                                 htons(NAMESERVER_PORT);
 314                         nserv++;
 315 #ifdef _LIBC
 316                         nservall++;
 317                     } else {
 318                         struct in6_addr a6;
 319                         char *el;
 320
 321                         if ((el = strchr(cp, '\n')) != NULL)
 322                             *el = '\0';
 323                         if ((*cp != '\0') &&
 324                             (inet_pton(AF_INET6, cp, &a6) > 0)) {
 325                             struct sockaddr_in6 *sa6;
 326
 327                             sa6 = malloc(sizeof(*sa6));
 328                             if (sa6 != NULL) {
 329                                 sa6->sin6_addr = a6;
 330                                 sa6->sin6_family = AF_INET6;
 331                                 sa6->sin6_port = htons(NAMESERVER_PORT);
 332                                 statp->_u._ext.nsaddrs[nservall] = sa6;
 333                                 statp->_u._ext.nssocks[nservall] = -1;
 334                                 statp->_u._ext.nsmap[nservall] = MAXNS + 1;
 335                                 nservall++;
 336                             }
 337                         }
 338 #endif
 339                     }
 340                     continue;
 341                 }
 342 #ifdef RESOLVSORT
 343                 if (MATCH(buf, "sortlist")) {
 344                     struct in_addr a;
 345
 346                     cp = buf + sizeof("sortlist") - 1;
 347                     while (nsort < MAXRESOLVSORT) {
 348                         while (*cp == ' ' || *cp == '\t')
 349                             cp++;
 350                         if (*cp == '\0' || *cp == '\n' || *cp == ';')
 351                             break;
 352                         net = cp;
 353                         while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
 354                                isascii(*cp) && !isspace(*cp))
 355                                 cp++;
 356                         n = *cp;
 357                         *cp = 0;
 358                         if (__inet_aton(net, &a)) {
 359                             statp->sort_list[nsort].addr = a;
 360                             if (ISSORTMASK(n)) {
 361                                 *cp++ = n;
 362                                 net = cp;
 363                                 while (*cp && *cp != ';' &&
 364                                         isascii(*cp) && !isspace(*cp))
 365                                     cp++;
 366                                 n = *cp;
 367                                 *cp = 0;
 368                                 if (__inet_aton(net, &a)) {
 369                                     statp->sort_list[nsort].mask = a.s_addr;
 370                                 } else {
 371                                     statp->sort_list[nsort].mask =
 372                                         net_mask(statp->sort_list[nsort].addr);
 373                                 }
 374                             } else {
 375                                 statp->sort_list[nsort].mask =
 376                                     net_mask(statp->sort_list[nsort].addr);
 377                             }
 378                             nsort++;
 379                         }
 380                         *cp = n;
 381                     }
 382                     continue;
 383                 }
 384 #endif
 385                 if (MATCH(buf, "options")) {
 386                     res_setoptions(statp, buf + sizeof("options") - 1, "conf");
 387                     continue;
 388                 }
 389             }
 390             if (nserv > 1)
 391                 statp->nscount = nserv;
 392 #ifdef _LIBC
 393             if (nservall - nserv > 0)
 394                 statp->_u._ext.nscount6 = nservall - nserv;
 395 #endif
 396 #ifdef RESOLVSORT
 397             statp->nsort = nsort;
 398 #endif
 399             (void) fclose(fp);
 400         }
 401         if (statp->defdname[0] == 0 &&
 402             __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
 403             (cp = strchr(buf, '.')) != NULL)
 404                 strcpy(statp->defdname, cp + 1);
 405
 406         /* find components of local domain that might be searched */
 407         if (havesearch == 0) {
 408                 pp = statp->dnsrch;
 409                 *pp++ = statp->defdname;
 410                 *pp = NULL;
 411
 412 #ifndef RFC1535
 413                 dots = 0;
 414                 for (cp = statp->defdname; *cp; cp++)
 415                         dots += (*cp == '.');
 416
 417                 cp = statp->defdname;
 418                 while (pp < statp->dnsrch + MAXDFLSRCH) {
 419                         if (dots < LOCALDOMAINPARTS)
 420                                 break;
 421                         cp = __rawmemchr(cp, '.') + 1;    /* we know there is one */
 422                         *pp++ = cp;
 423                         dots--;
 424                 }
 425                 *pp = NULL;
 426 #ifdef DEBUG
 427                 if (statp->options & RES_DEBUG) {
 428                         printf(";; res_init()... default dnsrch list:\n");
 429                         for (pp = statp->dnsrch; *pp; pp++)
 430                                 printf(";;\t%s\n", *pp);
 431                         printf(";;\t..END..\n");
 432                 }
 433 #endif
 434 #endif /* !RFC1535 */
 435         }
 436
 437         if ((cp = getenv("RES_OPTIONS")) != NULL)
 438                 res_setoptions(statp, cp, "env");
 439         statp->options |= RES_INIT;
 440         return (0);
 441 }
 442
 443 static void
 444 internal_function
 445 res_setoptions(res_state statp, const char *options, const char *source) {
 446         const char *cp = options;
 447         int i;
 448
 449 #ifdef DEBUG
 450         if (statp->options & RES_DEBUG)
 451                 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 452                        options, source);
 453 #endif
 454         while (*cp) {
 455                 /* skip leading and inner runs of spaces */
 456                 while (*cp == ' ' || *cp == '\t')
 457                         cp++;
 458                 /* search for and process individual options */
 459                 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
 460                         i = atoi(cp + sizeof("ndots:") - 1);
 461                         if (i <= RES_MAXNDOTS)
 462                                 statp->ndots = i;
 463                         else
 464                                 statp->ndots = RES_MAXNDOTS;
 465 #ifdef DEBUG
 466                         if (statp->options & RES_DEBUG)
 467                                 printf(";;\tndots=%d\n", statp->ndots);
 468 #endif
 469                 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
 470                         i = atoi(cp + sizeof("timeout:") - 1);
 471                         if (i <= RES_MAXRETRANS)
 472                                 statp->retrans = i;
 473                         else
 474                                 statp->retrans = RES_MAXRETRANS;
 475                 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
 476                         i = atoi(cp + sizeof("attempts:") - 1);
 477                         if (i <= RES_MAXRETRY)
 478                                 statp->retry = i;
 479                         else
 480                                 statp->retry = RES_MAXRETRY;
 481                 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 482 #ifdef DEBUG
 483                         if (!(statp->options & RES_DEBUG)) {
 484                                 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 485                                        options, source);
 486                                 statp->options |= RES_DEBUG;
 487                         }
 488                         printf(";;\tdebug\n");
 489 #endif
 490                 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
 491                         statp->options |= RES_USE_INET6;
 492                 } else if (!strncmp(cp, "ip6-bytestring",
 493                                     sizeof("ip6-bytestring") - 1)) {
 494                         statp->options |= RES_USEBSTRING;
 495                 } else if (!strncmp(cp, "no-ip6-dotint",
 496                                     sizeof("no-ip6-dotint") - 1)) {
 497                         statp->options |= RES_NOIP6DOTINT;
 498                 } else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
 499                         statp->options |= RES_ROTATE;
 500                 } else if (!strncmp(cp, "no-check-names",
 501                                     sizeof("no-check-names") - 1)) {
 502                         statp->options |= RES_NOCHECKNAME;
 503                 } else {
 504                         /* XXX - print a warning here? */
 505                 }
 506                 /* skip to next run of spaces */
 507                 while (*cp && *cp != ' ' && *cp != '\t')
 508                         cp++;
 509         }
 510 }
 511
 512 #ifdef RESOLVSORT
 513 /* XXX - should really support CIDR which means explicit masks always. */
 514 static u_int32_t
 515 net_mask(in)            /* XXX - should really use system's version of this */
 516         struct in_addr in;
 517 {
 518         register u_int32_t i = ntohl(in.s_addr);
 519
 520         if (IN_CLASSA(i))
 521                 return (htonl(IN_CLASSA_NET));
 522         else if (IN_CLASSB(i))
 523                 return (htonl(IN_CLASSB_NET));
 524         return (htonl(IN_CLASSC_NET));
 525 }
 526 #endif
 527
 528 u_int
 529 res_randomid(void) {
 530         struct timeval now;
 531
 532         __gettimeofday(&now, NULL);
 533         return (0xffff & (now.tv_sec ^ now.tv_usec ^ __getpid()));
 534 }
 535 #ifdef _LIBC
 536 libc_hidden_def (__res_randomid)
 537 #endif
 538
 539
 540 /*
 541  * This routine is for closing the socket if a virtual circuit is used and
 542  * the program wants to close it.  This provides support for endhostent()
 543  * which expects to close the socket.
 544  *
 545  * This routine is not expected to be user visible.
 546  */
 547 void
 548 res_nclose(res_state statp) {
 549         int ns;
 550
 551         if (statp->_vcsock >= 0) {
 552                 close_not_cancel_no_status(statp->_vcsock);
 553                 statp->_vcsock = -1;
 554                 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 555         }
 556 #ifdef _LIBC
 557         for (ns = 0; ns < MAXNS; ns++)
 558 #else
 559         for (ns = 0; ns < statp->_u._ext.nscount; ns++)
 560 #endif
 561                 if (statp->_u._ext.nsaddrs[ns]
 562                     && statp->_u._ext.nssocks[ns] != -1) {
 563                         close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
 564                         statp->_u._ext.nssocks[ns] = -1;
 565                 }
 566         statp->_u._ext.nsinit = 0;
 567 }
 568 #ifdef _LIBC
 569 libc_hidden_def (__res_nclose)
 570 #endif
 571
 572 #ifdef _LIBC
 573 # ifdef _LIBC_REENTRANT
 574 /* This is called when a thread is exiting to free resources held in _res.  */
 575 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
 576 res_thread_freeres (void)
 577 {
 578   if (_res.nscount == 0)
 579     /* Never called res_ninit.  */
 580     return;
 581
 582   __res_nclose (&_res);         /* Close any VC sockets.  */
 583
 584   for (int ns = 0; ns < MAXNS; ns++)
 585     if (_res._u._ext.nsaddrs[ns] != NULL)
 586       {
 587         free (_res._u._ext.nsaddrs[ns]);
 588         _res._u._ext.nsaddrs[ns] = NULL;
 589       }
 590 }
 591 text_set_element (__libc_thread_subfreeres, res_thread_freeres);
 592 text_set_element (__libc_subfreeres, res_thread_freeres);
 593 # endif
 594 #endif