pmon/lib/libc/res_init.c

/* $Id: res_init.c,v 1.1.1.1 2006/09/14 01:59:06 root Exp $ */
/*	$OpenBSD: res_init.c,v 1.18 1999/09/03 21:14:51 deraadt Exp $	*/

/*
 * ++Copyright++ 1985, 1989, 1993
 * -
 * Copyright (c) 1985, 1989, 1993
 *    The Regents of the University of California.  All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <stdio.h>
#include <ctype.h>
#include <resolv.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

/*-------------------------------------- info about "sortlist" --------------
 * Marc Majka		1994/04/16
 * Allan Nathanson	1994/10/29 (BIND 4.9.3.x)
 *
 * NetInfo resolver configuration directory support.
 *
 * Allow a NetInfo directory to be created in the hierarchy which
 * contains the same information as the resolver configuration file.
 *
 * - The local domain name is stored as the value of the "domain" property.
 * - The Internet address(es) of the name server(s) are stored as values
 *   of the "nameserver" property.
 * - The name server addresses are stored as values of the "nameserver"
 *   property.
 * - The search list for host-name lookup is stored as values of the
 *   "search" property.
 * - The sortlist comprised of IP address netmask pairs are stored as
 *   values of the "sortlist" property. The IP address and optional netmask
 *   should be seperated by a slash (/) or ampersand (&) character.
 * - Internal resolver variables can be set from the value of the "options"
 *   property.
 */

#ifndef PMON
static void res_setoptions __P((char *, char *));
#endif

#ifdef RESOLVSORT
static const char sort_mask[] = "/&";
#define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
static u_int32_t net_mask __P((struct in_addr));
#endif

/*
 * Resolver state default settings.
 */

struct __res_state _res
# if defined(__BIND_RES_TEXT)
	= { RES_TIMEOUT, }	/* Motorola, et al. */
# endif
	;

/*
 * Set up default settings.  If the configuration file exist, the values
 * there will have precedence.  Otherwise, the server address is set to
 * INADDR_ANY and the default domain name comes from the gethostname().
 *
 * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
 * rather than INADDR_ANY ("0.0.0.0") as the default name server address
 * since it was noted that INADDR_ANY actually meant ``the first interface
 * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
 * it had to be "up" in order for you to reach your own name server.  It
 * was later decided that since the recommended practice is to always 
 * install local static routes through 127.0.0.1 for all your network
 * interfaces, that we could solve this problem without a code change.
 *
 * The configuration file should always be used, since it is the only way
 * to specify a default domain.  If you are running a server on your local
 * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
 * in the configuration file.
 *
 * Return 0 if completes successfully, -1 on error
 */
int
res_init()
{
	int nserv = 0;    /* number of nameserver records read from file */
	char buf[MAXHOSTNAMELEN];
	register char *cp, **pp;
	register int n;
	int haveenv = 0;
	int havesearch = 0;
#ifndef RFC1535
	int dots;
#endif

	/*
	 * These three fields used to be statically initialized.  This made
	 * it hard to use this code in a shared library.  It is necessary,
	 * now that we're doing dynamic initialization here, that we preserve
	 * the old semantics: if an application modifies one of these three
	 * fields of _res before res_init() is called, res_init() will not
	 * alter them.  Of course, if an application is setting them to
	 * _zero_ before calling res_init(), hoping to override what used
	 * to be the static default, we can't detect it and unexpected results
	 * will follow.  Zero for any of these fields would make no sense,
	 * so one can safely assume that the applications were already getting
	 * unexpected results.
	 *
	 * _res.options is tricky since some apps were known to diddle the bits
	 * before res_init() was first called. We can't replicate that semantic
	 * with dynamic initialization (they may have turned bits off that are
	 * set in RES_DEFAULT).  Our solution is to declare such applications
	 * "broken".  They could fool us by setting RES_INIT but none do (yet).
	 */
	if (!_res.retrans)
		_res.retrans = RES_TIMEOUT;
	if (!_res.retry)
		_res.retry = 4;
	if (!(_res.options & RES_INIT))
		_res.options = RES_DEFAULT;

	_res.nsaddr.sin_addr.s_addr = INADDR_ANY;
	_res.nsaddr.sin_family = AF_INET;
	_res.nsaddr.sin_port = htons(NAMESERVER_PORT);
	_res.nscount = 1;
	_res.ndots = 1;
	_res.pfcode = 0;
	strncpy(_res.lookups, "f", sizeof _res.lookups);

	/* Allow user to override the local domain definition */
	if ((cp = getenv("localdomain")) != NULL) {
		(void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
		_res.defdname[sizeof(_res.defdname) - 1] = '\0';
		haveenv++;

		/*
		 * Set search list to be blank-separated strings
		 * from rest of env value.  Permits users of LOCALDOMAIN
		 * to still have a search list, and anyone to set the
		 * one that they want to use as an individual (even more
		 * important now that the rfc1535 stuff restricts searches)
		 */
		cp = _res.defdname;
		pp = _res.dnsrch;
		*pp++ = cp;
		for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
			if (*cp == '\n')	/* silly backwards compat */
				break;
			else if (*cp == ' ' || *cp == '\t') {
				*cp = 0;
				n = 1;
			} else if (n) {
				*pp++ = cp;
				n = 0;
				havesearch = 1;
			}
		}
		/* null terminate last domain if there are excess */
		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
			cp++;
		*cp = '\0';
		*pp++ = 0;
	}

	if ((cp = getenv("nameserver")) != NULL) {
		char *ep;
		strncpy (buf, cp, sizeof(buf)-1);
		for (cp = buf; cp && *cp; cp = ep) {
			if (*cp == ' ' || *cp == '\t') {
				cp++;
				continue;
			}
			ep = strpbrk(cp, " \t");
			if (ep != NULL)
				*ep++ = '\0';
			if ((_res.nsaddr_list[nserv].sin_addr.s_addr =
			    inet_addr(cp)) == (unsigned)-1) {
				_res.nsaddr_list[nserv].sin_addr.s_addr
				    = INADDR_ANY;
				continue;
			}
			_res.nsaddr_list[nserv].sin_family = AF_INET;
			_res.nsaddr_list[nserv].sin_port = htons(NAMESERVER_PORT);
			nserv++;
		}
        } 

	if (nserv > 1)
		_res.nscount = nserv;

	if (_res.defdname[0] == 0 &&
	    gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
	    (cp = strchr(buf, '.')) != NULL)
	{
		strncpy(_res.defdname, cp + 1,
		        sizeof(_res.defdname) - 1);
		_res.defdname[sizeof(_res.defdname) - 1] = '\0';
	}

	/* find components of local domain that might be searched */
	if (havesearch == 0) {
		pp = _res.dnsrch;
		*pp++ = _res.defdname;
		*pp = NULL;

#ifndef RFC1535
		dots = 0;
		for (cp = _res.defdname; *cp; cp++)
			dots += (*cp == '.');

		cp = _res.defdname;
		while (pp < _res.dnsrch + MAXDFLSRCH) {
			if (dots < LOCALDOMAINPARTS)
				break;
			cp = strchr(cp, '.') + 1;    /* we know there is one */
			*pp++ = cp;
			dots--;
		}
		*pp = NULL;
#ifdef DEBUG
		if (_res.options & RES_DEBUG) {
			printf(";; res_init()... default dnsrch list:\n");
			for (pp = _res.dnsrch; *pp; pp++)
				printf(";;\t%s\n", *pp);
			printf(";;\t..END..\n");
		}
#endif /* DEBUG */
#endif /* !RFC1535 */
	}

	_res.options |= RES_INIT;
	return (0);
}