193 lines
6.2 KiB
C
193 lines
6.2 KiB
C
/*-
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* Copyright (c) 1985, 1989 Regents of the University of California.
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* 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)res_init.c 6.15 (Berkeley) 2/24/91";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <sys/socket.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 <resolv.h>
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#include <unistd.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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/*
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* Resolver state default settings
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*/
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struct state _res = {
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RES_TIMEOUT, /* retransmition time interval */
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4, /* number of times to retransmit */
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RES_DEFAULT, /* options flags */
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1, /* number of name servers */
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};
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/*
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* Set up default settings. If the configuration file exist, the values
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* there will have precedence. Otherwise, the server address is set to
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* INADDR_ANY and the default domain name comes from the gethostname().
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*
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* The configuration file should only be used if you want to redefine your
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* domain or run without a server on your machine.
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*
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* Return 0 if completes successfully, -1 on error
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*/
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res_init()
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{
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register FILE *fp;
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register char *cp, **pp;
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register int n;
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char buf[BUFSIZ];
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int nserv = 0; /* number of nameserver records read from file */
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int haveenv = 0;
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int havesearch = 0;
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_res.nsaddr.sin_addr.s_addr = INADDR_ANY;
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_res.nsaddr.sin_family = AF_INET;
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_res.nsaddr.sin_port = htons(NAMESERVER_PORT);
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_res.nscount = 1;
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/* Allow user to override the local domain definition */
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if ((cp = getenv("LOCALDOMAIN")) != NULL) {
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(void)strncpy(_res.defdname, cp, sizeof(_res.defdname));
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haveenv++;
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}
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if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
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/* read the config file */
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while (fgets(buf, sizeof(buf), fp) != NULL) {
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/* read default domain name */
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if (!strncmp(buf, "domain", sizeof("domain") - 1)) {
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if (haveenv) /* skip if have from environ */
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continue;
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cp = buf + sizeof("domain") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if ((*cp == '\0') || (*cp == '\n'))
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continue;
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(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
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if ((cp = index(_res.defdname, '\n')) != NULL)
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*cp = '\0';
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havesearch = 0;
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continue;
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}
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/* set search list */
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if (!strncmp(buf, "search", sizeof("search") - 1)) {
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if (haveenv) /* skip if have from environ */
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continue;
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cp = buf + sizeof("search") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if ((*cp == '\0') || (*cp == '\n'))
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continue;
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(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
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if ((cp = index(_res.defdname, '\n')) != NULL)
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*cp = '\0';
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/*
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* Set search list to be blank-separated strings
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* on rest of line.
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*/
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cp = _res.defdname;
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pp = _res.dnsrch;
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*pp++ = cp;
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for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
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if (*cp == ' ' || *cp == '\t') {
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*cp = 0;
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n = 1;
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} else if (n) {
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*pp++ = cp;
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n = 0;
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}
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}
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/* null terminate last domain if there are excess */
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while (*cp != '\0' && *cp != ' ' && *cp != '\t')
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cp++;
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*cp = '\0';
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*pp++ = 0;
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havesearch = 1;
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continue;
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}
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/* read nameservers to query */
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if (!strncmp(buf, "nameserver", sizeof("nameserver") - 1) &&
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nserv < MAXNS) {
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cp = buf + sizeof("nameserver") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if ((*cp == '\0') || (*cp == '\n'))
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continue;
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if ((_res.nsaddr_list[nserv].sin_addr.s_addr =
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inet_addr(cp)) == (unsigned)-1) {
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_res.nsaddr_list[nserv].sin_addr.s_addr
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= INADDR_ANY;
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continue;
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}
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_res.nsaddr_list[nserv].sin_family = AF_INET;
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_res.nsaddr_list[nserv].sin_port = htons(NAMESERVER_PORT);
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nserv++;
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continue;
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}
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}
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if (nserv > 1)
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_res.nscount = nserv;
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(void) fclose(fp);
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}
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if (_res.defdname[0] == 0) {
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if (gethostname(buf, sizeof(_res.defdname)) == 0 &&
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(cp = index(buf, '.')))
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(void)strcpy(_res.defdname, cp + 1);
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}
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/* find components of local domain that might be searched */
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if (havesearch == 0) {
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pp = _res.dnsrch;
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*pp++ = _res.defdname;
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for (cp = _res.defdname, n = 0; *cp; cp++)
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if (*cp == '.')
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n++;
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cp = _res.defdname;
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for (; n >= LOCALDOMAINPARTS && pp < _res.dnsrch + MAXDFLSRCH;
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n--) {
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cp = index(cp, '.');
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*pp++ = ++cp;
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}
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*pp++ = 0;
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}
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_res.options |= RES_INIT;
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return (0);
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}
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