lib/libc/net/gethostbydns.c

   1 /*
   2  * ++Copyright++ 1985, 1988, 1993
   3  * -
   4  * Copyright (c) 1985, 1988, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  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  * --Copyright--
  50  *
  51  * @(#)gethostnamadr.c  8.1 (Berkeley) 6/4/93
  52  * From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $
  53  * $FreeBSD: src/lib/libc/net/gethostbydns.c,v 1.58 2007/01/09 00:28:02 imp Exp $
  54  */
  55
  56 #include <sys/types.h>
  57 #include <sys/param.h>
  58 #include <sys/socket.h>
  59 #include <netinet/in.h>
  60 #include <arpa/inet.h>
  61 #include <arpa/nameser.h>
  62
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <unistd.h>
  66 #include <string.h>
  67 #include <netdb.h>
  68 #include <resolv.h>
  69 #include <ctype.h>
  70 #include <errno.h>
  71 #include <syslog.h>
  72 #include <stdarg.h>
  73 #include <nsswitch.h>
  74
  75 #include "netdb_private.h"
  76 #include "res_config.h"
  77
  78 #define SPRINTF(x) ((size_t)sprintf x)
  79
  80 static const char AskedForGot[] =
  81                 "gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
  82
  83 #ifdef RESOLVSORT
  84 static void addrsort(char **, int, res_state);
  85 #endif
  86
  87 #ifdef DEBUG
  88 static void dbg_printf(char *, int, res_state) __printflike(1, 0);
  89 #endif
  90
  91 #define MAXPACKET       (64*1024)
  92
  93 typedef union {
  94     HEADER hdr;
  95     u_char buf[MAXPACKET];
  96 } querybuf;
  97
  98 typedef union {
  99     int32_t al;
 100     char ac;
 101 } align;
 102
 103 int _dns_ttl_;
 104
 105 #ifdef DEBUG
 106 static void
 107 dbg_printf(char *msg, int num, res_state res)
 108 {
 109         if (res->options & RES_DEBUG) {
 110                 int save = errno;
 111
 112                 printf(msg, num);
 113                 errno = save;
 114         }
 115 }
 116 #else
 117 # define dbg_printf(msg, num, res) /*nada*/
 118 #endif
 119
 120 #define BOUNDED_INCR(x) \
 121         do { \
 122                 cp += x; \
 123                 if (cp > eom) { \
 124                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 125                         return (-1); \
 126                 } \
 127         } while (0)
 128
 129 #define BOUNDS_CHECK(ptr, count) \
 130         do { \
 131                 if ((ptr) + (count) > eom) { \
 132                         RES_SET_H_ERRNO(statp, NO_RECOVERY); \
 133                         return (-1); \
 134                 } \
 135         } while (0)
 136
 137 static int
 138 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
 139               struct hostent *he, struct hostent_data *hed, res_state statp)
 140 {
 141         const HEADER *hp;
 142         const u_char *cp;
 143         int n;
 144         const u_char *eom, *erdata;
 145         char *bp, *ep, **ap, **hap;
 146         int type, class, ancount, qdcount;
 147         int haveanswer, had_error;
 148         int toobig = 0;
 149         char tbuf[MAXDNAME];
 150         const char *tname;
 151         int (*name_ok)(const char *);
 152
 153         tname = qname;
 154         he->h_name = NULL;
 155         eom = answer->buf + anslen;
 156         switch (qtype) {
 157         case T_A:
 158         case T_AAAA:
 159                 name_ok = res_hnok;
 160                 break;
 161         case T_PTR:
 162                 name_ok = res_dnok;
 163                 break;
 164         default:
 165                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 166                 return (-1);    /* XXX should be abort(); */
 167         }
 168         /*
 169          * find first satisfactory answer
 170          */
 171         hp = &answer->hdr;
 172         ancount = ntohs(hp->ancount);
 173         qdcount = ntohs(hp->qdcount);
 174         bp = hed->hostbuf;
 175         ep = hed->hostbuf + sizeof hed->hostbuf;
 176         cp = answer->buf;
 177         BOUNDED_INCR(HFIXEDSZ);
 178         if (qdcount != 1) {
 179                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 180                 return (-1);
 181         }
 182         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 183         if ((n < 0) || !(*name_ok)(bp)) {
 184                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 185                 return (-1);
 186         }
 187         BOUNDED_INCR(n + QFIXEDSZ);
 188         if (qtype == T_A || qtype == T_AAAA) {
 189                 /* res_send() has already verified that the query name is the
 190                  * same as the one we sent; this just gets the expanded name
 191                  * (i.e., with the succeeding search-domain tacked on).
 192                  */
 193                 n = strlen(bp) + 1;             /* for the \0 */
 194                 if (n >= MAXHOSTNAMELEN) {
 195                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 196                         return (-1);
 197                 }
 198                 he->h_name = bp;
 199                 bp += n;
 200                 /* The qname can be abbreviated, but h_name is now absolute. */
 201                 qname = he->h_name;
 202         }
 203         ap = hed->host_aliases;
 204         *ap = NULL;
 205         he->h_aliases = hed->host_aliases;
 206         hap = hed->h_addr_ptrs;
 207         *hap = NULL;
 208         he->h_addr_list = hed->h_addr_ptrs;
 209         haveanswer = 0;
 210         had_error = 0;
 211         _dns_ttl_ = -1;
 212         while (ancount-- > 0 && cp < eom && !had_error) {
 213                 n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 214                 if ((n < 0) || !(*name_ok)(bp)) {
 215                         had_error++;
 216                         continue;
 217                 }
 218                 cp += n;                        /* name */
 219                 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
 220                 type = _getshort(cp);
 221                 cp += INT16SZ;                  /* type */
 222                 class = _getshort(cp);
 223                 cp += INT16SZ;                  /* class */
 224                 if (qtype == T_A  && type == T_A)
 225                         _dns_ttl_ = _getlong(cp);
 226                 cp += INT32SZ;                  /* TTL */
 227                 n = _getshort(cp);
 228                 cp += INT16SZ;                  /* len */
 229                 BOUNDS_CHECK(cp, n);
 230                 erdata = cp + n;
 231                 if (class != C_IN) {
 232                         /* XXX - debug? syslog? */
 233                         cp += n;
 234                         continue;               /* XXX - had_error++ ? */
 235                 }
 236                 if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
 237                         if (ap >= &hed->host_aliases[_MAXALIASES-1])
 238                                 continue;
 239                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 240                         if ((n < 0) || !(*name_ok)(tbuf)) {
 241                                 had_error++;
 242                                 continue;
 243                         }
 244                         cp += n;
 245                         if (cp != erdata) {
 246                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 247                                 return (-1);
 248                         }
 249                         /* Store alias. */
 250                         *ap++ = bp;
 251                         n = strlen(bp) + 1;     /* for the \0 */
 252                         if (n >= MAXHOSTNAMELEN) {
 253                                 had_error++;
 254                                 continue;
 255                         }
 256                         bp += n;
 257                         /* Get canonical name. */
 258                         n = strlen(tbuf) + 1;   /* for the \0 */
 259                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 260                                 had_error++;
 261                                 continue;
 262                         }
 263                         strcpy(bp, tbuf);
 264                         he->h_name = bp;
 265                         bp += n;
 266                         continue;
 267                 }
 268                 if (qtype == T_PTR && type == T_CNAME) {
 269                         n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
 270                         if (n < 0 || !res_dnok(tbuf)) {
 271                                 had_error++;
 272                                 continue;
 273                         }
 274                         cp += n;
 275                         if (cp != erdata) {
 276                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 277                                 return (-1);
 278                         }
 279                         /* Get canonical name. */
 280                         n = strlen(tbuf) + 1;   /* for the \0 */
 281                         if (n > ep - bp || n >= MAXHOSTNAMELEN) {
 282                                 had_error++;
 283                                 continue;
 284                         }
 285                         strcpy(bp, tbuf);
 286                         tname = bp;
 287                         bp += n;
 288                         continue;
 289                 }
 290                 if (type != qtype) {
 291                         if (type != T_SIG)
 292                                 syslog(LOG_NOTICE|LOG_AUTH,
 293         "gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
 294                                        qname, p_class(C_IN), p_type(qtype),
 295                                        p_type(type));
 296                         cp += n;
 297                         continue;               /* XXX - had_error++ ? */
 298                 }
 299                 switch (type) {
 300                 case T_PTR:
 301                         if (strcasecmp(tname, bp) != 0) {
 302                                 syslog(LOG_NOTICE|LOG_AUTH,
 303                                        AskedForGot, qname, bp);
 304                                 cp += n;
 305                                 continue;       /* XXX - had_error++ ? */
 306                         }
 307                         n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
 308                         if ((n < 0) || !res_hnok(bp)) {
 309                                 had_error++;
 310                                 break;
 311                         }
 312 #if MULTI_PTRS_ARE_ALIASES
 313                         cp += n;
 314                         if (cp != erdata) {
 315                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 316                                 return (-1);
 317                         }
 318                         if (!haveanswer)
 319                                 he->h_name = bp;
 320                         else if (ap < &hed->host_aliases[_MAXALIASES-1])
 321                                 *ap++ = bp;
 322                         else
 323                                 n = -1;
 324                         if (n != -1) {
 325                                 n = strlen(bp) + 1;     /* for the \0 */
 326                                 if (n >= MAXHOSTNAMELEN) {
 327                                         had_error++;
 328                                         break;
 329                                 }
 330                                 bp += n;
 331                         }
 332                         break;
 333 #else
 334                         he->h_name = bp;
 335                         if (statp->options & RES_USE_INET6) {
 336                                 n = strlen(bp) + 1;     /* for the \0 */
 337                                 if (n >= MAXHOSTNAMELEN) {
 338                                         had_error++;
 339                                         break;
 340                                 }
 341                                 bp += n;
 342                                 _map_v4v6_hostent(he, &bp, ep);
 343                         }
 344                         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 345                         return (0);
 346 #endif
 347                 case T_A:
 348                 case T_AAAA:
 349                         if (strcasecmp(he->h_name, bp) != 0) {
 350                                 syslog(LOG_NOTICE|LOG_AUTH,
 351                                        AskedForGot, he->h_name, bp);
 352                                 cp += n;
 353                                 continue;       /* XXX - had_error++ ? */
 354                         }
 355                         if (n != he->h_length) {
 356                                 cp += n;
 357                                 continue;
 358                         }
 359                         if (!haveanswer) {
 360                                 int nn;
 361
 362                                 he->h_name = bp;
 363                                 nn = strlen(bp) + 1;    /* for the \0 */
 364                                 bp += nn;
 365                         }
 366
 367                         bp += sizeof(align) - ((u_long)bp % sizeof(align));
 368
 369                         if (bp + n >= ep) {
 370                                 dbg_printf("size (%d) too big\n", n, statp);
 371                                 had_error++;
 372                                 continue;
 373                         }
 374                         if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
 375                                 if (!toobig++)
 376                                         dbg_printf("Too many addresses (%d)\n",
 377                                                 _MAXADDRS, statp);
 378                                 cp += n;
 379                                 continue;
 380                         }
 381                         memcpy(*hap++ = bp, cp, n);
 382                         bp += n;
 383                         cp += n;
 384                         if (cp != erdata) {
 385                                 RES_SET_H_ERRNO(statp, NO_RECOVERY);
 386                                 return (-1);
 387                         }
 388                         break;
 389                 default:
 390                         dbg_printf("Impossible condition (type=%d)\n", type,
 391                             statp);
 392                         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 393                         return (-1);
 394                         /* BIND has abort() here, too risky on bad data */
 395                 }
 396                 if (!had_error)
 397                         haveanswer++;
 398         }
 399         if (haveanswer) {
 400                 *ap = NULL;
 401                 *hap = NULL;
 402 # if defined(RESOLVSORT)
 403                 /*
 404                  * Note: we sort even if host can take only one address
 405                  * in its return structures - should give it the "best"
 406                  * address in that case, not some random one
 407                  */
 408                 if (statp->nsort && haveanswer > 1 && qtype == T_A)
 409                         addrsort(hed->h_addr_ptrs, haveanswer, statp);
 410 # endif /*RESOLVSORT*/
 411                 if (!he->h_name) {
 412                         n = strlen(qname) + 1;  /* for the \0 */
 413                         if (n > ep - bp || n >= MAXHOSTNAMELEN)
 414                                 goto no_recovery;
 415                         strcpy(bp, qname);
 416                         he->h_name = bp;
 417                         bp += n;
 418                 }
 419                 if (statp->options & RES_USE_INET6)
 420                         _map_v4v6_hostent(he, &bp, ep);
 421                 RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 422                 return (0);
 423         }
 424  no_recovery:
 425         RES_SET_H_ERRNO(statp, NO_RECOVERY);
 426         return (-1);
 427 }
 428
 429 /* XXX: for async DNS resolver in ypserv */
 430 struct hostent *
 431 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
 432 {
 433         struct hostent *he;
 434         struct hostent_data *hed;
 435         int error;
 436         res_state statp;
 437
 438         statp = __res_state();
 439         if ((he = __hostent_init()) == NULL ||
 440             (hed = __hostent_data_init()) == NULL) {
 441                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 442                 return (NULL);
 443         }
 444         switch (qtype) {
 445         case T_AAAA:
 446                 he->h_addrtype = AF_INET6;
 447                 he->h_length = NS_IN6ADDRSZ;
 448                 break;
 449         case T_A:
 450         default:
 451                 he->h_addrtype = AF_INET;
 452                 he->h_length = NS_INADDRSZ;
 453                 break;
 454         }
 455
 456         error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
 457             he, hed, statp);
 458         return (error == 0) ? he : NULL;
 459 }
 460
 461 int
 462 _dns_gethostbyname(void *rval, void *cb_data __unused, va_list ap)
 463 {
 464         const char *name;
 465         int af;
 466         char *buffer;
 467         size_t buflen;
 468         int *errnop __unused;
 469         int *h_errnop;
 470         struct hostent *hptr, he;
 471         struct hostent_data *hed;
 472         querybuf *buf;
 473         int n, type, error;
 474         res_state statp;
 475
 476         name = va_arg(ap, const char *);
 477         af = va_arg(ap, int);
 478         hptr = va_arg(ap, struct hostent *);
 479         buffer = va_arg(ap, char *);
 480         buflen = va_arg(ap, size_t);
 481         errnop = va_arg(ap, int *);
 482         h_errnop = va_arg(ap, int *);
 483
 484         *((struct hostent **)rval) = NULL;
 485
 486         statp = __res_state();
 487         if ((hed = __hostent_data_init()) == NULL) {
 488                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 489                 *h_errnop = statp->res_h_errno;
 490                 return (NS_NOTFOUND);
 491         }
 492
 493         he.h_addrtype = af;
 494         switch (af) {
 495         case AF_INET:
 496                 he.h_length = NS_INADDRSZ;
 497                 type = T_A;
 498                 break;
 499         case AF_INET6:
 500                 he.h_length = NS_IN6ADDRSZ;
 501                 type = T_AAAA;
 502                 break;
 503         default:
 504                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 505                 *h_errnop = statp->res_h_errno;
 506                 errno = EAFNOSUPPORT;
 507                 return (NS_UNAVAIL);
 508         }
 509
 510         if ((buf = malloc(sizeof(*buf))) == NULL) {
 511                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 512                 *h_errnop = statp->res_h_errno;
 513                 return (NS_NOTFOUND);
 514         }
 515         n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
 516         if (n < 0) {
 517                 free(buf);
 518                 dbg_printf("res_nsearch failed (%d)\n", n, statp);
 519                 *h_errnop = statp->res_h_errno;
 520                 return (0);
 521         } else if (n > sizeof(buf->buf)) {
 522                 free(buf);
 523                 dbg_printf("static buffer is too small (%d)\n", n, statp);
 524                 *h_errnop = statp->res_h_errno;
 525                 return (0);
 526         }
 527         error = gethostanswer(buf, n, name, type, &he, hed, statp);
 528         free(buf);
 529         if (error != 0) {
 530                 *h_errnop = statp->res_h_errno;
 531                 return (NS_NOTFOUND);
 532         }
 533         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 534                 *h_errnop = statp->res_h_errno;
 535                 return (NS_NOTFOUND);
 536         }
 537         *((struct hostent **)rval) = hptr;
 538         return (NS_SUCCESS);
 539 }
 540
 541 int
 542 _dns_gethostbyaddr(void *rval, void *cb_data __unused, va_list ap)
 543 {
 544         const void *addr;
 545         socklen_t len;
 546         int af;
 547         char *buffer;
 548         size_t buflen;
 549         int *errnop __unused;
 550         int *h_errnop;
 551         const u_char *uaddr;
 552         struct hostent *hptr, he;
 553         struct hostent_data *hed;
 554         int n;
 555         querybuf *buf;
 556         char qbuf[MAXDNAME+1], *qp;
 557         res_state statp;
 558 #ifdef SUNSECURITY
 559         struct hostdata rhd;
 560         struct hostent *rhe;
 561         char **haddr;
 562         u_long old_options;
 563         char hname2[MAXDNAME+1], numaddr[46];
 564         int ret_h_error;
 565 #endif /*SUNSECURITY*/
 566
 567         addr = va_arg(ap, const void *);
 568         len = va_arg(ap, socklen_t);
 569         af = va_arg(ap, int);
 570         hptr = va_arg(ap, struct hostent *);
 571         buffer = va_arg(ap, char *);
 572         buflen = va_arg(ap, size_t);
 573         errnop = va_arg(ap, int *);
 574         h_errnop = va_arg(ap, int *);
 575         uaddr = (const u_char *)addr;
 576
 577         *((struct hostent **)rval) = NULL;
 578
 579         statp = __res_state();
 580         if ((hed = __hostent_data_init()) == NULL) {
 581                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 582                 *h_errnop = statp->res_h_errno;
 583                 return (NS_NOTFOUND);
 584         }
 585
 586         switch (af) {
 587         case AF_INET:
 588                 sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 589                                (uaddr[3] & 0xff),
 590                                (uaddr[2] & 0xff),
 591                                (uaddr[1] & 0xff),
 592                                (uaddr[0] & 0xff));
 593                 break;
 594         case AF_INET6:
 595                 qp = qbuf;
 596                 for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
 597                         qp += SPRINTF((qp, "%x.%x.",
 598                                        uaddr[n] & 0xf,
 599                                        (uaddr[n] >> 4) & 0xf));
 600                 }
 601                 strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
 602                 break;
 603         default:
 604                 abort();
 605         }
 606         if ((buf = malloc(sizeof(*buf))) == NULL) {
 607                 RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
 608                 *h_errnop = statp->res_h_errno;
 609                 return NS_NOTFOUND;
 610         }
 611         n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
 612             sizeof buf->buf);
 613         if (n < 0) {
 614                 free(buf);
 615                 dbg_printf("res_nquery failed (%d)\n", n, statp);
 616                 *h_errnop = statp->res_h_errno;
 617                 return (NS_UNAVAIL);
 618         }
 619         if (n > sizeof buf->buf) {
 620                 free(buf);
 621                 dbg_printf("static buffer is too small (%d)\n", n, statp);
 622                 *h_errnop = statp->res_h_errno;
 623                 return (NS_UNAVAIL);
 624         }
 625         if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
 626                 free(buf);
 627                 *h_errnop = statp->res_h_errno;
 628                 return (NS_NOTFOUND);   /* h_errno was set by gethostanswer() */
 629         }
 630         free(buf);
 631 #ifdef SUNSECURITY
 632         if (af == AF_INET) {
 633             /*
 634              * turn off search as the name should be absolute,
 635              * 'localhost' should be matched by defnames
 636              */
 637             strncpy(hname2, he.h_name, MAXDNAME);
 638             hname2[MAXDNAME] = '\0';
 639             old_options = statp->options;
 640             statp->options &= ~RES_DNSRCH;
 641             statp->options |= RES_DEFNAMES;
 642             memset(&rhd, 0, sizeof rhd);
 643             rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
 644                 sizeof(rhd.data), &ret_h_error);
 645             if (rhe == NULL) {
 646                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 647                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 648                 syslog(LOG_NOTICE|LOG_AUTH,
 649                        "gethostbyaddr: No A record for %s (verifying [%s])",
 650                        hname2, numaddr);
 651                 statp->options = old_options;
 652                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 653                 *h_errnop = statp->res_h_errno;
 654                 return (NS_NOTFOUND);
 655             }
 656             statp->options = old_options;
 657             for (haddr = rhe->h_addr_list; *haddr; haddr++)
 658                 if (!memcmp(*haddr, addr, NS_INADDRSZ))
 659                         break;
 660             if (!*haddr) {
 661                 if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
 662                     strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
 663                 syslog(LOG_NOTICE|LOG_AUTH,
 664                        "gethostbyaddr: A record of %s != PTR record [%s]",
 665                        hname2, numaddr);
 666                 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 667                 *h_errnop = statp->res_h_errno;
 668                 return (NS_NOTFOUND);
 669             }
 670         }
 671 #endif /*SUNSECURITY*/
 672         he.h_addrtype = af;
 673         he.h_length = len;
 674         memcpy(hed->host_addr, uaddr, len);
 675         hed->h_addr_ptrs[0] = (char *)hed->host_addr;
 676         hed->h_addr_ptrs[1] = NULL;
 677         if (af == AF_INET && (statp->options & RES_USE_INET6)) {
 678                 _map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
 679                 he.h_addrtype = AF_INET6;
 680                 he.h_length = NS_IN6ADDRSZ;
 681         }
 682         RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
 683         if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
 684                 *h_errnop = statp->res_h_errno;
 685                 return (NS_NOTFOUND);
 686         }
 687         *((struct hostent **)rval) = hptr;
 688         return (NS_SUCCESS);
 689 }
 690
 691 #ifdef RESOLVSORT
 692 static void
 693 addrsort(char **ap, int num, res_state res)
 694 {
 695         int i, j;
 696         char **p;
 697         short aval[_MAXADDRS];
 698         int needsort = 0;
 699
 700         p = ap;
 701         for (i = 0; i < num; i++, p++) {
 702             for (j = 0 ; (unsigned)j < res->nsort; j++)
 703                 if (res->sort_list[j].addr.s_addr ==
 704                     (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
 705                         break;
 706             aval[i] = j;
 707             if (needsort == 0 && i > 0 && j < aval[i-1])
 708                 needsort = i;
 709         }
 710         if (!needsort)
 711             return;
 712
 713         while (needsort < num) {
 714             for (j = needsort - 1; j >= 0; j--) {
 715                 if (aval[j] > aval[j+1]) {
 716                     char *hp;
 717
 718                     i = aval[j];
 719                     aval[j] = aval[j+1];
 720                     aval[j+1] = i;
 721
 722                     hp = ap[j];
 723                     ap[j] = ap[j+1];
 724                     ap[j+1] = hp;
 725
 726                 } else
 727                     break;
 728             }
 729             needsort++;
 730         }
 731 }
 732 #endif
 733
 734 void
 735 _sethostdnsent(int stayopen)
 736 {
 737         res_state statp;
 738
 739         statp = __res_state();
 740         if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
 741                 return;
 742         if (stayopen)
 743                 statp->options |= RES_STAYOPEN | RES_USEVC;
 744 }
 745
 746 void
 747 _endhostdnsent(void)
 748 {
 749         res_state statp;
 750
 751         statp = __res_state();
 752         statp->options &= ~(RES_STAYOPEN | RES_USEVC);
 753         res_nclose(statp);
 754 }