resolv/res_query.c

   1 /*
   2  * Copyright (c) 1988, 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 #include <assert.h>
  68 #include <sys/types.h>
  69 #include <sys/param.h>
  70 #include <netinet/in.h>
  71 #include <arpa/inet.h>
  72 #include <arpa/nameser.h>
  73 #include <ctype.h>
  74 #include <errno.h>
  75 #include <netdb.h>
  76 #include <resolv.h>
  77 #include <resolv/resolv-internal.h>
  78 #include <resolv/resolv_context.h>
  79 #include <stdio.h>
  80 #include <stdlib.h>
  81 #include <string.h>
  82 #include <shlib-compat.h>
  83
  84 #if PACKETSZ > 65536
  85 #define MAXPACKET       PACKETSZ
  86 #else
  87 #define MAXPACKET       65536
  88 #endif
  89
  90 #define QUERYSIZE       (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)
  91
  92 static int
  93 __res_context_querydomain (struct resolv_context *,
  94                            const char *name, const char *domain,
  95                            int class, int type, unsigned char *answer, int anslen,
  96                            unsigned char **answerp, unsigned char **answerp2, int *nanswerp2,
  97                            int *resplen2, int *answerp2_malloced);
  98
  99 /* Formulate a normal query, send, and await answer.  Returned answer
 100    is placed in supplied buffer ANSWER.  Perform preliminary check of
 101    answer, returning success only if no error is indicated and the
 102    answer count is nonzero.  Return the size of the response on
 103    success, -1 on error.  Error number is left in h_errno.
 104
 105    Caller must parse answer and determine whether it answers the
 106    question.  */
 107 int
 108 __res_context_query (struct resolv_context *ctx, const char *name,
 109                      int class, int type,
 110                      unsigned char *answer, int anslen,
 111                      unsigned char **answerp, unsigned char **answerp2,
 112                      int *nanswerp2, int *resplen2, int *answerp2_malloced)
 113 {
 114         struct __res_state *statp = ctx->resp;
 115         UHEADER *hp = (UHEADER *) answer;
 116         UHEADER *hp2;
 117         int n, use_malloc = 0;
 118
 119         size_t bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * QUERYSIZE;
 120         u_char *buf = alloca (bufsize);
 121         u_char *query1 = buf;
 122         int nquery1 = -1;
 123         u_char *query2 = NULL;
 124         int nquery2 = 0;
 125
 126  again:
 127         hp->rcode = NOERROR;    /* default */
 128
 129         if (type == T_QUERY_A_AND_AAAA)
 130           {
 131             n = __res_context_mkquery (ctx, QUERY, name, class, T_A, NULL,
 132                                        query1, bufsize);
 133             if (n > 0)
 134               {
 135                 if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
 136                   {
 137                     /* Use RESOLV_EDNS_BUFFER_SIZE because the receive
 138                        buffer can be reallocated.  */
 139                     n = __res_nopt (ctx, n, query1, bufsize,
 140                                     RESOLV_EDNS_BUFFER_SIZE);
 141                     if (n < 0)
 142                       goto unspec_nomem;
 143                   }
 144
 145                 nquery1 = n;
 146                 /* Align the buffer.  */
 147                 int npad = ((nquery1 + __alignof__ (HEADER) - 1)
 148                             & ~(__alignof__ (HEADER) - 1)) - nquery1;
 149                 if (n > bufsize - npad)
 150                   {
 151                     n = -1;
 152                     goto unspec_nomem;
 153                   }
 154                 int nused = n + npad;
 155                 query2 = buf + nused;
 156                 n = __res_context_mkquery (ctx, QUERY, name, class, T_AAAA,
 157                                            NULL, query2, bufsize - nused);
 158                 if (n > 0
 159                     && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
 160                   /* Use RESOLV_EDNS_BUFFER_SIZE because the receive
 161                      buffer can be reallocated.  */
 162                   n = __res_nopt (ctx, n, query2, bufsize,
 163                                   RESOLV_EDNS_BUFFER_SIZE);
 164                 nquery2 = n;
 165               }
 166
 167           unspec_nomem:;
 168           }
 169         else
 170           {
 171             n = __res_context_mkquery (ctx, QUERY, name, class, type, NULL,
 172                                        query1, bufsize);
 173
 174             if (n > 0
 175                 && (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
 176               {
 177                 /* Use RESOLV_EDNS_BUFFER_SIZE if the receive buffer
 178                    can be reallocated.  */
 179                 size_t advertise;
 180                 if (answerp == NULL)
 181                   advertise = anslen;
 182                 else
 183                   advertise = RESOLV_EDNS_BUFFER_SIZE;
 184                 n = __res_nopt (ctx, n, query1, bufsize, advertise);
 185               }
 186
 187             nquery1 = n;
 188           }
 189
 190         if (__glibc_unlikely (n <= 0) && !use_malloc) {
 191                 /* Retry just in case res_nmkquery failed because of too
 192                    short buffer.  Shouldn't happen.  */
 193                 bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * MAXPACKET;
 194                 buf = malloc (bufsize);
 195                 if (buf != NULL) {
 196                         query1 = buf;
 197                         use_malloc = 1;
 198                         goto again;
 199                 }
 200         }
 201         if (__glibc_unlikely (n <= 0))       {
 202                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 203                 if (use_malloc)
 204                         free (buf);
 205                 return (n);
 206         }
 207
 208         /* Suppress AAAA lookups if required.  __res_handle_no_aaaa
 209            checks RES_NOAAAA first, so avoids parsing the
 210            just-generated query packet in most cases.  nss_dns avoids
 211            using T_QUERY_A_AND_AAAA in RES_NOAAAA mode, so there is no
 212            need to handle it here.  */
 213         if (type == T_AAAA && __res_handle_no_aaaa (ctx, query1, nquery1,
 214                                                     answer, anslen, &n))
 215           /* There must be no second query for AAAA queries.  The code
 216              below is still needed to translate NODATA responses.  */
 217           assert (query2 == NULL);
 218         else
 219           {
 220             assert (answerp == NULL || (void *) *answerp == (void *) answer);
 221             n = __res_context_send (ctx, query1, nquery1, query2, nquery2,
 222                                     answer, anslen,
 223                                     answerp, answerp2, nanswerp2, resplen2,
 224                                     answerp2_malloced);
 225           }
 226
 227         if (use_malloc)
 228                 free (buf);
 229         if (n < 0) {
 230                 RES_SET_H_ERRNO(statp, TRY_AGAIN);
 231                 return (n);
 232         }
 233
 234         if (answerp != NULL)
 235           /* __res_context_send might have reallocated the buffer.  */
 236           hp = (UHEADER *) *answerp;
 237
 238         /* We simplify the following tests by assigning HP to HP2 or
 239            vice versa.  It is easy to verify that this is the same as
 240            ignoring all tests of HP or HP2.  */
 241         if (answerp2 == NULL || *resplen2 < (int) sizeof (HEADER))
 242           {
 243             hp2 = hp;
 244           }
 245         else
 246           {
 247             hp2 = (UHEADER *) *answerp2;
 248             if (n < (int) sizeof (HEADER))
 249               {
 250                 hp = hp2;
 251               }
 252           }
 253
 254         /* Make sure both hp and hp2 are defined */
 255         assert((hp != NULL) && (hp2 != NULL));
 256
 257         if ((hp->rcode != NOERROR || ntohs(hp->ancount) == 0)
 258             && (hp2->rcode != NOERROR || ntohs(hp2->ancount) == 0)) {
 259                 switch (hp->rcode == NOERROR ? hp2->rcode : hp->rcode) {
 260                 case NXDOMAIN:
 261                         if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0)
 262                             || (hp2->rcode == NOERROR
 263                                 && ntohs (hp2->ancount) != 0))
 264                                 goto success;
 265                         RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 266                         break;
 267                 case SERVFAIL:
 268                         RES_SET_H_ERRNO(statp, TRY_AGAIN);
 269                         break;
 270                 case NOERROR:
 271                         if (ntohs (hp->ancount) != 0
 272                             || ntohs (hp2->ancount) != 0)
 273                                 goto success;
 274                         RES_SET_H_ERRNO(statp, NO_DATA);
 275                         break;
 276                 case FORMERR:
 277                 case NOTIMP:
 278                         /* Servers must not reply to AAAA queries with
 279                            NOTIMP etc but some of them do.  */
 280                         if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0)
 281                             || (hp2->rcode == NOERROR
 282                                 && ntohs (hp2->ancount) != 0))
 283                                 goto success;
 284                         /* FALLTHROUGH */
 285                 case REFUSED:
 286                 default:
 287                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 288                         break;
 289                 }
 290                 return (-1);
 291         }
 292  success:
 293         return (n);
 294 }
 295 libc_hidden_def (__res_context_query)
 296
 297 /* Common part of res_nquery and res_query.  */
 298 static int
 299 context_query_common (struct resolv_context *ctx,
 300                       const char *name, int class, int type,
 301                       unsigned char *answer, int anslen)
 302 {
 303   if (ctx == NULL)
 304     {
 305       RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);
 306       return -1;
 307     }
 308   int result = __res_context_query (ctx, name, class, type, answer, anslen,
 309                                     NULL, NULL, NULL, NULL, NULL);
 310   __resolv_context_put (ctx);
 311   return result;
 312 }
 313
 314 int
 315 ___res_nquery (res_state statp,
 316                const char *name,      /* Domain name.  */
 317                int class, int type,   /* Class and type of query.  */
 318                unsigned char *answer, /* Buffer to put answer.  */
 319                int anslen)            /* Size of answer buffer.  */
 320 {
 321   return context_query_common
 322     (__resolv_context_get_override (statp), name, class, type, answer, anslen);
 323 }
 324 versioned_symbol (libc, ___res_nquery, res_nquery, GLIBC_2_34);
 325 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 326 compat_symbol (libresolv, ___res_nquery, __res_nquery, GLIBC_2_2);
 327 #endif
 328
 329 int
 330 ___res_query (const char *name, int class, int type,
 331               unsigned char *answer, int anslen)
 332 {
 333   return context_query_common
 334     (__resolv_context_get (), name, class, type, answer, anslen);
 335 }
 336 versioned_symbol (libc, ___res_query, res_query, GLIBC_2_34);
 337 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
 338 compat_symbol (libresolv, ___res_query, res_query, GLIBC_2_0);
 339 #endif
 340 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 341 compat_symbol (libresolv, ___res_query, __res_query, GLIBC_2_2);
 342 #endif
 343
 344 /* Formulate a normal query, send, and retrieve answer in supplied
 345    buffer.  Return the size of the response on success, -1 on error.
 346    If enabled, implement search rules until answer or unrecoverable
 347    failure is detected.  Error code, if any, is left in h_errno.  */
 348 int
 349 __res_context_search (struct resolv_context *ctx,
 350                       const char *name, int class, int type,
 351                       unsigned char *answer, int anslen,
 352                       unsigned char **answerp, unsigned char **answerp2,
 353                       int *nanswerp2, int *resplen2, int *answerp2_malloced)
 354 {
 355         struct __res_state *statp = ctx->resp;
 356         const char *cp;
 357         UHEADER *hp = (UHEADER *) answer;
 358         char tmp[NS_MAXDNAME];
 359         u_int dots;
 360         int trailing_dot, ret, saved_herrno;
 361         int got_nodata = 0, got_servfail = 0, root_on_list = 0;
 362         int tried_as_is = 0;
 363         int searched = 0;
 364
 365         __set_errno (0);
 366         RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);  /* True if we never query. */
 367
 368         dots = 0;
 369         for (cp = name; *cp != '\0'; cp++)
 370                 dots += (*cp == '.');
 371         trailing_dot = 0;
 372         if (cp > name && *--cp == '.')
 373                 trailing_dot++;
 374
 375         /* If there aren't any dots, it could be a user-level alias. */
 376         if (!dots && (cp = __res_context_hostalias
 377                       (ctx, name, tmp, sizeof tmp))!= NULL)
 378           return __res_context_query (ctx, cp, class, type, answer,
 379                                       anslen, answerp, answerp2,
 380                                       nanswerp2, resplen2, answerp2_malloced);
 381
 382         /*
 383          * If there are enough dots in the name, let's just give it a
 384          * try 'as is'. The threshold can be set with the "ndots" option.
 385          * Also, query 'as is', if there is a trailing dot in the name.
 386          */
 387         saved_herrno = -1;
 388         if (dots >= statp->ndots || trailing_dot) {
 389                 ret = __res_context_querydomain (ctx, name, NULL, class, type,
 390                                                  answer, anslen, answerp,
 391                                                  answerp2, nanswerp2, resplen2,
 392                                                  answerp2_malloced);
 393                 if (ret > 0 || trailing_dot
 394                     /* If the second response is valid then we use that.  */
 395                     || (ret == 0 && resplen2 != NULL && *resplen2 > 0))
 396                         return (ret);
 397                 saved_herrno = h_errno;
 398                 tried_as_is++;
 399                 if (answerp && *answerp != answer) {
 400                         answer = *answerp;
 401                         anslen = MAXPACKET;
 402                 }
 403                 if (answerp2 && *answerp2_malloced)
 404                   {
 405                     free (*answerp2);
 406                     *answerp2 = NULL;
 407                     *nanswerp2 = 0;
 408                     *answerp2_malloced = 0;
 409                   }
 410         }
 411
 412         /*
 413          * We do at least one level of search if
 414          *      - there is no dot and RES_DEFNAME is set, or
 415          *      - there is at least one dot, there is no trailing dot,
 416          *        and RES_DNSRCH is set.
 417          */
 418         if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
 419             (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
 420                 int done = 0;
 421
 422                 for (size_t domain_index = 0; !done; ++domain_index) {
 423                         const char *dname = __resolv_context_search_list
 424                           (ctx, domain_index);
 425                         if (dname == NULL)
 426                           break;
 427                         searched = 1;
 428
 429                         /* __res_context_querydoman concatenates name
 430                            with dname with a "." in between.  If we
 431                            pass it in dname the "." we got from the
 432                            configured default search path, we'll end
 433                            up with "name..", which won't resolve.
 434                            OTOH, passing it "" will result in "name.",
 435                            which has the intended effect for both
 436                            possible representations of the root
 437                            domain.  */
 438                         if (dname[0] == '.')
 439                                 dname++;
 440                         if (dname[0] == '\0')
 441                                 root_on_list++;
 442
 443                         ret = __res_context_querydomain
 444                           (ctx, name, dname, class, type,
 445                            answer, anslen, answerp, answerp2, nanswerp2,
 446                            resplen2, answerp2_malloced);
 447                         if (ret > 0 || (ret == 0 && resplen2 != NULL
 448                                         && *resplen2 > 0))
 449                                 return (ret);
 450
 451                         if (answerp && *answerp != answer) {
 452                                 answer = *answerp;
 453                                 anslen = MAXPACKET;
 454                         }
 455                         if (answerp2 && *answerp2_malloced)
 456                           {
 457                             free (*answerp2);
 458                             *answerp2 = NULL;
 459                             *nanswerp2 = 0;
 460                             *answerp2_malloced = 0;
 461                           }
 462
 463                         /*
 464                          * If no server present, give up.
 465                          * If name isn't found in this domain,
 466                          * keep trying higher domains in the search list
 467                          * (if that's enabled).
 468                          * On a NO_DATA error, keep trying, otherwise
 469                          * a wildcard entry of another type could keep us
 470                          * from finding this entry higher in the domain.
 471                          * If we get some other error (negative answer or
 472                          * server failure), then stop searching up,
 473                          * but try the input name below in case it's
 474                          * fully-qualified.
 475                          */
 476                         if (errno == ECONNREFUSED) {
 477                                 RES_SET_H_ERRNO(statp, TRY_AGAIN);
 478                                 return (-1);
 479                         }
 480
 481                         switch (statp->res_h_errno) {
 482                         case NO_DATA:
 483                                 got_nodata++;
 484                                 /* FALLTHROUGH */
 485                         case HOST_NOT_FOUND:
 486                                 /* keep trying */
 487                                 break;
 488                         case TRY_AGAIN:
 489                                 if (hp->rcode == SERVFAIL) {
 490                                         /* try next search element, if any */
 491                                         got_servfail++;
 492                                         break;
 493                                 }
 494                                 /* FALLTHROUGH */
 495                         default:
 496                                 /* anything else implies that we're done */
 497                                 done++;
 498                         }
 499
 500                         /* if we got here for some reason other than DNSRCH,
 501                          * we only wanted one iteration of the loop, so stop.
 502                          */
 503                         if ((statp->options & RES_DNSRCH) == 0)
 504                                 done++;
 505                 }
 506         }
 507
 508         /*
 509          * If the query has not already been tried as is then try it
 510          * unless RES_NOTLDQUERY is set and there were no dots.
 511          */
 512         if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0)
 513             && !(tried_as_is || root_on_list)) {
 514                 ret = __res_context_querydomain
 515                   (ctx, name, NULL, class, type,
 516                    answer, anslen, answerp, answerp2, nanswerp2,
 517                    resplen2, answerp2_malloced);
 518                 if (ret > 0 || (ret == 0 && resplen2 != NULL
 519                                 && *resplen2 > 0))
 520                         return (ret);
 521         }
 522
 523         /* if we got here, we didn't satisfy the search.
 524          * if we did an initial full query, return that query's H_ERRNO
 525          * (note that we wouldn't be here if that query had succeeded).
 526          * else if we ever got a nodata, send that back as the reason.
 527          * else send back meaningless H_ERRNO, that being the one from
 528          * the last DNSRCH we did.
 529          */
 530         if (answerp2 && *answerp2_malloced)
 531           {
 532             free (*answerp2);
 533             *answerp2 = NULL;
 534             *nanswerp2 = 0;
 535             *answerp2_malloced = 0;
 536           }
 537         if (saved_herrno != -1)
 538                 RES_SET_H_ERRNO(statp, saved_herrno);
 539         else if (got_nodata)
 540                 RES_SET_H_ERRNO(statp, NO_DATA);
 541         else if (got_servfail)
 542                 RES_SET_H_ERRNO(statp, TRY_AGAIN);
 543         return (-1);
 544 }
 545 libc_hidden_def (__res_context_search)
 546
 547 /* Common part of res_nsearch and res_search.  */
 548 static int
 549 context_search_common (struct resolv_context *ctx,
 550                        const char *name, int class, int type,
 551                        unsigned char *answer, int anslen)
 552 {
 553   if (ctx == NULL)
 554     {
 555       RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);
 556       return -1;
 557     }
 558   int result = __res_context_search (ctx, name, class, type, answer, anslen,
 559                                      NULL, NULL, NULL, NULL, NULL);
 560   __resolv_context_put (ctx);
 561   return result;
 562 }
 563
 564 int
 565 ___res_nsearch (res_state statp,
 566                 const char *name,      /* Domain name.  */
 567                 int class, int type,   /* Class and type of query.  */
 568                 unsigned char *answer, /* Buffer to put answer.  */
 569                 int anslen)            /* Size of answer.  */
 570 {
 571   return context_search_common
 572     (__resolv_context_get_override (statp), name, class, type, answer, anslen);
 573 }
 574 versioned_symbol (libc, ___res_nsearch, res_nsearch, GLIBC_2_34);
 575 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 576 compat_symbol (libresolv, ___res_nsearch, __res_nsearch, GLIBC_2_2);
 577 #endif
 578
 579 int
 580 ___res_search (const char *name, int class, int type,
 581                unsigned char *answer, int anslen)
 582 {
 583   return context_search_common
 584     (__resolv_context_get (), name, class, type, answer, anslen);
 585 }
 586 versioned_symbol (libc, ___res_search, res_search, GLIBC_2_34);
 587 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
 588 compat_symbol (libresolv, ___res_search, res_search, GLIBC_2_0);
 589 #endif
 590 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 591 compat_symbol (libresolv, ___res_search, __res_search, GLIBC_2_2);
 592 #endif
 593
 594 /*  Perform a call on res_query on the concatenation of name and
 595     domain.  */
 596 static int
 597 __res_context_querydomain (struct resolv_context *ctx,
 598                            const char *name, const char *domain,
 599                            int class, int type,
 600                            unsigned char *answer, int anslen,
 601                            unsigned char **answerp, unsigned char **answerp2,
 602                            int *nanswerp2, int *resplen2,
 603                            int *answerp2_malloced)
 604 {
 605         struct __res_state *statp = ctx->resp;
 606         char nbuf[MAXDNAME];
 607         const char *longname = nbuf;
 608         size_t n, d;
 609
 610         if (domain == NULL) {
 611                 n = strlen(name);
 612
 613                 /* Decrement N prior to checking it against MAXDNAME
 614                    so that we detect a wrap to SIZE_MAX and return
 615                    a reasonable error.  */
 616                 n--;
 617                 if (n >= MAXDNAME - 1) {
 618                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 619                         return (-1);
 620                 }
 621                 longname = name;
 622         } else {
 623                 n = strlen(name);
 624                 d = strlen(domain);
 625                 if (n + d + 1 >= MAXDNAME) {
 626                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 627                         return (-1);
 628                 }
 629                 char *p = __stpcpy (nbuf, name);
 630                 *p++ = '.';
 631                 strcpy (p, domain);
 632         }
 633         return __res_context_query (ctx, longname, class, type, answer,
 634                                     anslen, answerp, answerp2, nanswerp2,
 635                                     resplen2, answerp2_malloced);
 636 }
 637
 638 /* Common part of res_nquerydomain and res_querydomain.  */
 639 static int
 640 context_querydomain_common (struct resolv_context *ctx,
 641                             const char *name, const char *domain,
 642                             int class, int type,
 643                             unsigned char *answer, int anslen)
 644 {
 645   if (ctx == NULL)
 646     {
 647       RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);
 648       return -1;
 649     }
 650   int result = __res_context_querydomain (ctx, name, domain, class, type,
 651                                           answer, anslen,
 652                                           NULL, NULL, NULL, NULL, NULL);
 653   __resolv_context_put (ctx);
 654   return result;
 655 }
 656
 657 int
 658 ___res_nquerydomain (res_state statp,
 659                      const char *name,
 660                      const char *domain,
 661                      int class, int type, /* Class and type of query.  */
 662                      unsigned char *answer, /* Buffer to put answer.  */
 663                      int anslen)            /* Size of answer.  */
 664 {
 665   return context_querydomain_common
 666     (__resolv_context_get_override (statp),
 667      name, domain, class, type, answer, anslen);
 668 }
 669 versioned_symbol (libc, ___res_nquerydomain, res_nquerydomain, GLIBC_2_34);
 670 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 671 compat_symbol (libresolv, ___res_nquerydomain, __res_nquerydomain, GLIBC_2_2);
 672 #endif
 673
 674 int
 675 ___res_querydomain (const char *name, const char *domain, int class, int type,
 676                     unsigned char *answer, int anslen)
 677 {
 678   return context_querydomain_common
 679     (__resolv_context_get (), name, domain, class, type, answer, anslen);
 680 }
 681 versioned_symbol (libc, ___res_querydomain, res_querydomain, GLIBC_2_34);
 682 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
 683 compat_symbol (libresolv, ___res_querydomain, res_querydomain, GLIBC_2_0);
 684 #endif
 685 #if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
 686 compat_symbol (libresolv, ___res_querydomain, __res_querydomain, GLIBC_2_2);
 687 #endif