637 lines
18 KiB
C
637 lines
18 KiB
C
/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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/*
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
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static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vixie Exp $";
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#endif /* LIBC_SCCS and not lint */
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#include <assert.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <ctype.h>
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#include <errno.h>
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#include <netdb.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/* Options. Leave them on. */
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/* #undef DEBUG */
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#if PACKETSZ > 65536
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#define MAXPACKET PACKETSZ
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#else
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#define MAXPACKET 65536
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#endif
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#define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)
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static int
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__libc_res_nquerydomain(res_state statp, const char *name, const char *domain,
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int class, int type, u_char *answer, int anslen,
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u_char **answerp, u_char **answerp2, int *nanswerp2,
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int *resplen2);
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/*
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* Formulate a normal query, send, and await answer.
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* Returned answer is placed in supplied buffer "answer".
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* Perform preliminary check of answer, returning success only
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* if no error is indicated and the answer count is nonzero.
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* Return the size of the response on success, -1 on error.
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* Error number is left in H_ERRNO.
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*
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* Caller must parse answer and determine whether it answers the question.
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*/
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int
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__libc_res_nquery(res_state statp,
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const char *name, /* domain name */
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int class, int type, /* class and type of query */
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u_char *answer, /* buffer to put answer */
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int anslen, /* size of answer buffer */
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u_char **answerp, /* if buffer needs to be enlarged */
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u_char **answerp2,
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int *nanswerp2,
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int *resplen2)
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{
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HEADER *hp = (HEADER *) answer;
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HEADER *hp2;
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int n, use_malloc = 0;
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u_int oflags = statp->_flags;
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size_t bufsize = (type == T_UNSPEC ? 2 : 1) * QUERYSIZE;
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u_char *buf = alloca (bufsize);
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u_char *query1 = buf;
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int nquery1 = -1;
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u_char *query2 = NULL;
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int nquery2 = 0;
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again:
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hp->rcode = NOERROR; /* default */
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_query(%s, %d, %d)\n", name, class, type);
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#endif
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if (type == T_UNSPEC)
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{
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n = res_nmkquery(statp, QUERY, name, class, T_A, NULL, 0, NULL,
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query1, bufsize);
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if (n > 0)
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{
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if ((oflags & RES_F_EDNS0ERR) == 0
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&& (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
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{
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n = __res_nopt(statp, n, query1, bufsize, anslen / 2);
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if (n < 0)
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goto unspec_nomem;
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}
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nquery1 = n;
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/* Align the buffer. */
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int npad = ((nquery1 + __alignof__ (HEADER) - 1)
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& ~(__alignof__ (HEADER) - 1)) - nquery1;
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if (n > bufsize - npad)
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{
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n = -1;
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goto unspec_nomem;
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}
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int nused = n + npad;
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query2 = buf + nused;
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n = res_nmkquery(statp, QUERY, name, class, T_AAAA, NULL, 0,
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NULL, query2, bufsize - nused);
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if (n > 0
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&& (oflags & RES_F_EDNS0ERR) == 0
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&& (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
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n = __res_nopt(statp, n, query2, bufsize - nused - n,
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anslen / 2);
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nquery2 = n;
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}
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unspec_nomem:;
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}
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else
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{
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n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
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query1, bufsize);
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if (n > 0
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&& (oflags & RES_F_EDNS0ERR) == 0
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&& (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0)
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n = __res_nopt(statp, n, query1, bufsize, anslen);
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nquery1 = n;
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}
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if (__builtin_expect (n <= 0, 0) && !use_malloc) {
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/* Retry just in case res_nmkquery failed because of too
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short buffer. Shouldn't happen. */
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bufsize = (type == T_UNSPEC ? 2 : 1) * MAXPACKET;
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buf = malloc (bufsize);
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if (buf != NULL) {
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query1 = buf;
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use_malloc = 1;
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goto again;
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}
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}
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if (__builtin_expect (n <= 0, 0)) {
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/* If the query choked with EDNS0, retry without EDNS0. */
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if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0
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&& ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) {
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statp->_flags |= RES_F_EDNS0ERR;
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_nquery: retry without EDNS0\n");
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#endif
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goto again;
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}
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_query: mkquery failed\n");
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#endif
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RES_SET_H_ERRNO(statp, NO_RECOVERY);
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if (use_malloc)
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free (buf);
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return (n);
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}
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assert (answerp == NULL || (void *) *answerp == (void *) answer);
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n = __libc_res_nsend(statp, query1, nquery1, query2, nquery2, answer,
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anslen, answerp, answerp2, nanswerp2, resplen2);
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if (use_malloc)
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free (buf);
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if (n < 0) {
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_query: send error\n");
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#endif
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RES_SET_H_ERRNO(statp, TRY_AGAIN);
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return (n);
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}
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if (answerp != NULL)
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/* __libc_res_nsend might have reallocated the buffer. */
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hp = (HEADER *) *answerp;
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/* We simplify the following tests by assigning HP to HP2 or
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vice versa. It is easy to verify that this is the same as
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ignoring all tests of HP or HP2. */
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if (answerp2 == NULL || *resplen2 < (int) sizeof (HEADER))
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{
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hp2 = hp;
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}
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else
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{
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hp2 = (HEADER *) *answerp2;
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if (n < (int) sizeof (HEADER))
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{
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hp = hp2;
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}
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}
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/* Make sure both hp and hp2 are defined */
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assert((hp != NULL) && (hp2 != NULL));
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if ((hp->rcode != NOERROR || ntohs(hp->ancount) == 0)
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&& (hp2->rcode != NOERROR || ntohs(hp2->ancount) == 0)) {
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#ifdef DEBUG
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if (statp->options & RES_DEBUG) {
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printf(";; rcode = %d, ancount=%d\n", hp->rcode,
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ntohs(hp->ancount));
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if (hp != hp2)
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printf(";; rcode2 = %d, ancount2=%d\n", hp2->rcode,
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ntohs(hp2->ancount));
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}
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#endif
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switch (hp->rcode == NOERROR ? hp2->rcode : hp->rcode) {
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case NXDOMAIN:
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if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0)
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|| (hp2->rcode == NOERROR
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&& ntohs (hp2->ancount) != 0))
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goto success;
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RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
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break;
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case SERVFAIL:
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RES_SET_H_ERRNO(statp, TRY_AGAIN);
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break;
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case NOERROR:
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if (ntohs (hp->ancount) != 0
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|| ntohs (hp2->ancount) != 0)
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goto success;
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RES_SET_H_ERRNO(statp, NO_DATA);
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break;
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case FORMERR:
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case NOTIMP:
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/* Servers must not reply to AAAA queries with
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NOTIMP etc but some of them do. */
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if ((hp->rcode == NOERROR && ntohs (hp->ancount) != 0)
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|| (hp2->rcode == NOERROR
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&& ntohs (hp2->ancount) != 0))
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goto success;
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/* FALLTHROUGH */
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case REFUSED:
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default:
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RES_SET_H_ERRNO(statp, NO_RECOVERY);
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break;
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}
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return (-1);
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}
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success:
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return (n);
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}
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libresolv_hidden_def (__libc_res_nquery)
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int
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res_nquery(res_state statp,
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const char *name, /* domain name */
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int class, int type, /* class and type of query */
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u_char *answer, /* buffer to put answer */
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int anslen) /* size of answer buffer */
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{
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return __libc_res_nquery(statp, name, class, type, answer, anslen,
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NULL, NULL, NULL, NULL);
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}
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libresolv_hidden_def (res_nquery)
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/*
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* Formulate a normal query, send, and retrieve answer in supplied buffer.
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* Return the size of the response on success, -1 on error.
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* If enabled, implement search rules until answer or unrecoverable failure
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* is detected. Error code, if any, is left in H_ERRNO.
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*/
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int
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__libc_res_nsearch(res_state statp,
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const char *name, /* domain name */
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int class, int type, /* class and type of query */
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u_char *answer, /* buffer to put answer */
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int anslen, /* size of answer */
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u_char **answerp,
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u_char **answerp2,
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int *nanswerp2,
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int *resplen2)
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{
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const char *cp, * const *domain;
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HEADER *hp = (HEADER *) answer;
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char tmp[NS_MAXDNAME];
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u_int dots;
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int trailing_dot, ret, saved_herrno;
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int got_nodata = 0, got_servfail = 0, root_on_list = 0;
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int tried_as_is = 0;
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int searched = 0;
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__set_errno (0);
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RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */
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dots = 0;
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for (cp = name; *cp != '\0'; cp++)
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dots += (*cp == '.');
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trailing_dot = 0;
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if (cp > name && *--cp == '.')
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trailing_dot++;
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/* If there aren't any dots, it could be a user-level alias. */
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if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
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return (__libc_res_nquery(statp, cp, class, type, answer,
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anslen, answerp, answerp2,
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nanswerp2, resplen2));
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf("dots=%d, statp->ndots=%d, trailing_dot=%d, name=%s\n",
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(int)dots,(int)statp->ndots,(int)trailing_dot,name);
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#endif
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/*
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* If there are enough dots in the name, let's just give it a
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* try 'as is'. The threshold can be set with the "ndots" option.
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* Also, query 'as is', if there is a trailing dot in the name.
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*/
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saved_herrno = -1;
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if (dots >= statp->ndots || trailing_dot) {
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ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
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answer, anslen, answerp,
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answerp2, nanswerp2, resplen2);
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if (ret > 0 || trailing_dot)
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return (ret);
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saved_herrno = h_errno;
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tried_as_is++;
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if (answerp && *answerp != answer) {
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answer = *answerp;
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anslen = MAXPACKET;
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}
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if (answerp2
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&& (*answerp2 < answer || *answerp2 >= answer + anslen))
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{
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free (*answerp2);
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*answerp2 = NULL;
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}
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}
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/*
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* We do at least one level of search if
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* - there is no dot and RES_DEFNAME is set, or
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* - there is at least one dot, there is no trailing dot,
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* and RES_DNSRCH is set.
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*/
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if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
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(dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
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int done = 0;
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for (domain = (const char * const *)statp->dnsrch;
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*domain && !done;
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domain++) {
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searched = 1;
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if (domain[0][0] == '\0' ||
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(domain[0][0] == '.' && domain[0][1] == '\0'))
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root_on_list++;
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ret = __libc_res_nquerydomain(statp, name, *domain,
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class, type,
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answer, anslen, answerp,
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answerp2, nanswerp2,
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resplen2);
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if (ret > 0)
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return (ret);
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if (answerp && *answerp != answer) {
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answer = *answerp;
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anslen = MAXPACKET;
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}
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if (answerp2
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&& (*answerp2 < answer
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|| *answerp2 >= answer + anslen))
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{
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free (*answerp2);
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*answerp2 = NULL;
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}
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/*
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* If no server present, give up.
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* If name isn't found in this domain,
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* keep trying higher domains in the search list
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* (if that's enabled).
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* On a NO_DATA error, keep trying, otherwise
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* a wildcard entry of another type could keep us
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* from finding this entry higher in the domain.
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* If we get some other error (negative answer or
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* server failure), then stop searching up,
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* but try the input name below in case it's
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* fully-qualified.
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*/
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if (errno == ECONNREFUSED) {
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RES_SET_H_ERRNO(statp, TRY_AGAIN);
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return (-1);
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}
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switch (statp->res_h_errno) {
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case NO_DATA:
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got_nodata++;
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/* FALLTHROUGH */
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case HOST_NOT_FOUND:
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/* keep trying */
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break;
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case TRY_AGAIN:
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if (hp->rcode == SERVFAIL) {
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/* try next search element, if any */
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got_servfail++;
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break;
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}
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/* FALLTHROUGH */
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default:
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/* anything else implies that we're done */
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done++;
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}
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/* if we got here for some reason other than DNSRCH,
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* we only wanted one iteration of the loop, so stop.
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*/
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if ((statp->options & RES_DNSRCH) == 0)
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done++;
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}
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}
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/*
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* f the query has not already been tried as is then try it
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* unless RES_NOTLDQUERY is set and there were no dots.
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*/
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if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0)
|
|
&& !(tried_as_is || root_on_list)) {
|
|
ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
|
|
answer, anslen, answerp,
|
|
answerp2, nanswerp2, resplen2);
|
|
if (ret > 0)
|
|
return (ret);
|
|
}
|
|
|
|
/* if we got here, we didn't satisfy the search.
|
|
* if we did an initial full query, return that query's H_ERRNO
|
|
* (note that we wouldn't be here if that query had succeeded).
|
|
* else if we ever got a nodata, send that back as the reason.
|
|
* else send back meaningless H_ERRNO, that being the one from
|
|
* the last DNSRCH we did.
|
|
*/
|
|
if (answerp2 && (*answerp2 < answer || *answerp2 >= answer + anslen))
|
|
{
|
|
free (*answerp2);
|
|
*answerp2 = NULL;
|
|
}
|
|
if (saved_herrno != -1)
|
|
RES_SET_H_ERRNO(statp, saved_herrno);
|
|
else if (got_nodata)
|
|
RES_SET_H_ERRNO(statp, NO_DATA);
|
|
else if (got_servfail)
|
|
RES_SET_H_ERRNO(statp, TRY_AGAIN);
|
|
return (-1);
|
|
}
|
|
libresolv_hidden_def (__libc_res_nsearch)
|
|
|
|
int
|
|
res_nsearch(res_state statp,
|
|
const char *name, /* domain name */
|
|
int class, int type, /* class and type of query */
|
|
u_char *answer, /* buffer to put answer */
|
|
int anslen) /* size of answer */
|
|
{
|
|
return __libc_res_nsearch(statp, name, class, type, answer,
|
|
anslen, NULL, NULL, NULL, NULL);
|
|
}
|
|
libresolv_hidden_def (res_nsearch)
|
|
|
|
/*
|
|
* Perform a call on res_query on the concatenation of name and domain,
|
|
* removing a trailing dot from name if domain is NULL.
|
|
*/
|
|
static int
|
|
__libc_res_nquerydomain(res_state statp,
|
|
const char *name,
|
|
const char *domain,
|
|
int class, int type, /* class and type of query */
|
|
u_char *answer, /* buffer to put answer */
|
|
int anslen, /* size of answer */
|
|
u_char **answerp,
|
|
u_char **answerp2,
|
|
int *nanswerp2,
|
|
int *resplen2)
|
|
{
|
|
char nbuf[MAXDNAME];
|
|
const char *longname = nbuf;
|
|
size_t n, d;
|
|
|
|
#ifdef DEBUG
|
|
if (statp->options & RES_DEBUG)
|
|
printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
|
|
name, domain?domain:"<Nil>", class, type);
|
|
#endif
|
|
if (domain == NULL) {
|
|
/*
|
|
* Check for trailing '.';
|
|
* copy without '.' if present.
|
|
*/
|
|
n = strlen(name);
|
|
|
|
/* Decrement N prior to checking it against MAXDNAME
|
|
so that we detect a wrap to SIZE_MAX and return
|
|
a reasonable error. */
|
|
n--;
|
|
if (n >= MAXDNAME - 1) {
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
return (-1);
|
|
}
|
|
if (name[n] == '.') {
|
|
strncpy(nbuf, name, n);
|
|
nbuf[n] = '\0';
|
|
} else
|
|
longname = name;
|
|
} else {
|
|
n = strlen(name);
|
|
d = strlen(domain);
|
|
if (n + d + 1 >= MAXDNAME) {
|
|
RES_SET_H_ERRNO(statp, NO_RECOVERY);
|
|
return (-1);
|
|
}
|
|
sprintf(nbuf, "%s.%s", name, domain);
|
|
}
|
|
return (__libc_res_nquery(statp, longname, class, type, answer,
|
|
anslen, answerp, answerp2, nanswerp2,
|
|
resplen2));
|
|
}
|
|
|
|
int
|
|
res_nquerydomain(res_state statp,
|
|
const char *name,
|
|
const char *domain,
|
|
int class, int type, /* class and type of query */
|
|
u_char *answer, /* buffer to put answer */
|
|
int anslen) /* size of answer */
|
|
{
|
|
return __libc_res_nquerydomain(statp, name, domain, class, type,
|
|
answer, anslen, NULL, NULL, NULL, NULL);
|
|
}
|
|
libresolv_hidden_def (res_nquerydomain)
|
|
|
|
const char *
|
|
res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
|
|
char *file, *cp1, *cp2;
|
|
char buf[BUFSIZ];
|
|
FILE *fp;
|
|
|
|
if (statp->options & RES_NOALIASES)
|
|
return (NULL);
|
|
file = getenv("HOSTALIASES");
|
|
if (file == NULL || (fp = fopen(file, "rce")) == NULL)
|
|
return (NULL);
|
|
setbuf(fp, NULL);
|
|
buf[sizeof(buf) - 1] = '\0';
|
|
while (fgets(buf, sizeof(buf), fp)) {
|
|
for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)
|
|
;
|
|
if (!*cp1)
|
|
break;
|
|
*cp1 = '\0';
|
|
if (ns_samename(buf, name) == 1) {
|
|
while (isspace(*++cp1))
|
|
;
|
|
if (!*cp1)
|
|
break;
|
|
for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
|
|
;
|
|
*cp2 = '\0';
|
|
strncpy(dst, cp1, siz - 1);
|
|
dst[siz - 1] = '\0';
|
|
fclose(fp);
|
|
return (dst);
|
|
}
|
|
}
|
|
fclose(fp);
|
|
return (NULL);
|
|
}
|
|
libresolv_hidden_def (res_hostalias)
|