450 lines
14 KiB
C
450 lines
14 KiB
C
/*-
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* Copyright (c) 1985, 1989, 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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* 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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* 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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* --Copyright--
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93";
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static char rcsid[] = "$Id: res_init.c,v 1.6 1995/08/21 09:15:36 bde Exp $";
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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 <sys/time.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 <stdio.h>
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#include <ctype.h>
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#include <resolv.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include "res_config.h"
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static void res_setoptions __P((char *, char *));
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#ifdef RESOLVSORT
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static const char sort_mask[] = "/&";
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#define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
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static u_int32_t net_mask __P((struct in_addr));
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#endif
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/*
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* Resolver state default settings.
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*/
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struct __res_state _res;
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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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* An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
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* rather than INADDR_ANY ("0.0.0.0") as the default name server address
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* since it was noted that INADDR_ANY actually meant ``the first interface
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* you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
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* it had to be "up" in order for you to reach your own name server. It
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* was later decided that since the recommended practice is to always
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* install local static routes through 127.0.0.1 for all your network
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* interfaces, that we could solve this problem without a code change.
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*
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* The configuration file should always be used, since it is the only way
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* to specify a default domain. If you are running a server on your local
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* machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
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* in the configuration file.
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*
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* Return 0 if completes successfully, -1 on error
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*/
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int
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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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#ifdef RESOLVSORT
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int nsort = 0;
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char *net;
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#endif
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#ifndef RFC1535
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int dots;
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#endif
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/*
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* These three fields used to be statically initialized. This made
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* it hard to use this code in a shared library. It is necessary,
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* now that we're doing dynamic initialization here, that we preserve
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* the old semantics: if an application modifies one of these three
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* fields of _res before res_init() is called, res_init() will not
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* alter them. Of course, if an application is setting them to
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* _zero_ before calling res_init(), hoping to override what used
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* to be the static default, we can't detect it and unexpected results
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* will follow. Zero for any of these fields would make no sense,
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* so one can safely assume that the applications were already getting
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* unexpected results.
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*
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* _res.options is tricky since some apps were known to diddle the bits
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* before res_init() was first called. We can't replicate that semantic
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* with dynamic initialization (they may have turned bits off that are
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* set in RES_DEFAULT). Our solution is to declare such applications
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* "broken". They could fool us by setting RES_INIT but none do (yet).
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*/
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if (!_res.retrans)
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_res.retrans = RES_TIMEOUT;
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if (!_res.retry)
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_res.retry = 4;
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if (!(_res.options & RES_INIT))
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_res.options = RES_DEFAULT;
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/*
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* This one used to initialize implicitly to zero, so unless the app
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* has set it to something in particular, we can randomize it now.
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*/
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if (!_res.id)
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_res.id = res_randomid();
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#ifdef USELOOPBACK
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_res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
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#else
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_res.nsaddr.sin_addr.s_addr = INADDR_ANY;
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#endif
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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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_res.ndots = 1;
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_res.pfcode = 0;
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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) - 1);
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haveenv++;
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/*
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* Set search list to be blank-separated strings
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* from rest of env value. Permits users of LOCALDOMAIN
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* to still have a search list, and anyone to set the
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* one that they want to use as an individual (even more
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* important now that the rfc1535 stuff restricts searches)
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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 == '\n') /* silly backwards compat */
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break;
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else 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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havesearch = 1;
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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' && *cp != '\n')
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cp++;
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*cp = '\0';
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*pp++ = 0;
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}
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#define MATCH(line, name) \
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(!strncmp(line, name, sizeof(name) - 1) && \
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(line[sizeof(name) - 1] == ' ' || \
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line[sizeof(name) - 1] == '\t'))
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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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/* skip comments */
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if (*buf == ';' || *buf == '#')
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continue;
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/* read default domain name */
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if (MATCH(buf, "domain")) {
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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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strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
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if ((cp = strpbrk(_res.defdname, " \t\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 (MATCH(buf, "search")) {
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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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strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
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if ((cp = strchr(_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 (MATCH(buf, "nameserver") && nserv < MAXNS) {
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struct in_addr a;
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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') && inet_aton(cp, &a)) {
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_res.nsaddr_list[nserv].sin_addr = a;
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_res.nsaddr_list[nserv].sin_family = AF_INET;
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_res.nsaddr_list[nserv].sin_port =
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htons(NAMESERVER_PORT);
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nserv++;
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}
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continue;
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}
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#ifdef RESOLVSORT
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if (MATCH(buf, "sortlist")) {
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struct in_addr a;
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cp = buf + sizeof("sortlist") - 1;
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while (nsort < MAXRESOLVSORT) {
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if (*cp == '\0' || *cp == '\n' || *cp == ';')
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break;
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net = cp;
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while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
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isascii(*cp) && !isspace(*cp))
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cp++;
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n = *cp;
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*cp = 0;
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if (inet_aton(net, &a)) {
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_res.sort_list[nsort].addr = a;
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if (ISSORTMASK(n)) {
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*cp++ = n;
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net = cp;
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while (*cp && *cp != ';' &&
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isascii(*cp) && !isspace(*cp))
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cp++;
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n = *cp;
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*cp = 0;
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if (inet_aton(net, &a)) {
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_res.sort_list[nsort].mask = a.s_addr;
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} else {
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_res.sort_list[nsort].mask =
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net_mask(_res.sort_list[nsort].addr);
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}
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} else {
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_res.sort_list[nsort].mask =
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net_mask(_res.sort_list[nsort].addr);
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}
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nsort++;
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}
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*cp = n;
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}
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continue;
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}
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#endif
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if (MATCH(buf, "options")) {
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res_setoptions(buf + sizeof("options") - 1, "conf");
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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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#ifdef RESOLVSORT
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_res.nsort = nsort;
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#endif
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(void) fclose(fp);
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}
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if (_res.defdname[0] == 0 &&
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gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
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(cp = strchr(buf, '.')) != NULL)
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strcpy(_res.defdname, cp + 1);
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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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*pp = NULL;
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#ifndef RFC1535
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dots = 0;
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for (cp = _res.defdname; *cp; cp++)
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dots += (*cp == '.');
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cp = _res.defdname;
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while (pp < _res.dnsrch + MAXDFLSRCH) {
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if (dots < LOCALDOMAINPARTS)
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break;
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cp = strchr(cp, '.') + 1; /* we know there is one */
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*pp++ = cp;
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dots--;
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}
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*pp = NULL;
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#ifdef DEBUG
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if (_res.options & RES_DEBUG) {
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printf(";; res_init()... default dnsrch list:\n");
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for (pp = _res.dnsrch; *pp; pp++)
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printf(";;\t%s\n", *pp);
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printf(";;\t..END..\n");
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}
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#endif /* DEBUG */
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#endif /* !RFC1535 */
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}
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if ((cp = getenv("RES_OPTIONS")) != NULL)
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res_setoptions(cp, "env");
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_res.options |= RES_INIT;
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return (0);
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}
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static void
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res_setoptions(options, source)
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char *options, *source;
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{
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char *cp = options;
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int i;
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf(";; res_setoptions(\"%s\", \"%s\")...\n",
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options, source);
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#endif
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while (*cp) {
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/* skip leading and inner runs of spaces */
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while (*cp == ' ' || *cp == '\t')
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cp++;
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/* search for and process individual options */
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if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
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i = atoi(cp + sizeof("ndots:") - 1);
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if (i <= RES_MAXNDOTS)
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_res.ndots = i;
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else
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_res.ndots = RES_MAXNDOTS;
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf(";;\tndots=%d\n", _res.ndots);
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#endif
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} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
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#ifdef DEBUG
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if (!(_res.options & RES_DEBUG)) {
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printf(";; res_setoptions(\"%s\", \"%s\")..\n",
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options, source);
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_res.options |= RES_DEBUG;
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}
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printf(";;\tdebug\n");
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#endif
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} else {
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/* XXX - print a warning here? */
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}
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/* skip to next run of spaces */
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while (*cp && *cp != ' ' && *cp != '\t')
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cp++;
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}
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}
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#ifdef RESOLVSORT
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/* XXX - should really support CIDR which means explicit masks always. */
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static u_int32_t
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net_mask(in) /* XXX - should really use system's version of this */
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struct in_addr in;
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{
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register u_int32_t i = ntohl(in.s_addr);
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if (IN_CLASSA(i))
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return (htonl(IN_CLASSA_NET));
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else if (IN_CLASSB(i))
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return (htonl(IN_CLASSB_NET));
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return (htonl(IN_CLASSC_NET));
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}
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#endif
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u_int16_t
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res_randomid()
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{
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struct timeval now;
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gettimeofday(&now, NULL);
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return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
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}
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