/*-
 * Copyright (c) 1985, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/* $Id: res_init.c,v 1.1.1.1 2005/06/27 03:02:34 sheik Exp $ */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include "config.h"		/* To get #define SOL20 */
#include "sys.h"
#include "nameser.h"
#include "resolv.h"

/* Resolver state default settings */
struct state _res =
{
    RES_TIMEOUT,		/* retransmition time interval */
    4,				/* number of times to retransmit */
    RES_DEFAULT,		/* options flags */
    1,				/* number of name servers */
};

/*
 * 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().
 * 
 * The configuration file should only be used if you want to redefine your
 * domain or run without a server on your machine.
 * 
 * Return 0 if completes successfully, -1 on error
 */
int res_init()
{
    FILE *fp;
    char *cp, *dp, **pp;
    int n;
    char        buf[BUFSIZ];
    extern u_long inet_addr();
    extern char *getenv();
    int         nserv = 0;   /* number of nameserver records read from file */
    int         norder = 0;
    int         haveenv = 0;
    int         havesearch = 0;

    _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
    _res.nsaddr.sin_family = AF_INET;
    _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
    _res.nscount = 1;

    /* Allow user to override the local domain definition */
    if ((cp = getenv("LOCALDOMAIN")) != NULL)
    {
	(void) strncpy(_res.defdname, cp, sizeof(_res.defdname));
	haveenv++;
    }

    if ((fp = fopen(_PATH_RESCONF, "r")) != NULL)
    {
	/* read the config file */
	while (fgets(buf, sizeof(buf), fp) != NULL)
	{
	    /* read default domain name */
	    if (!strncmp(buf, "domain", sizeof("domain") - 1))
	    {
		if (haveenv)	/* skip if have from environ */
		    continue;
		cp = buf + sizeof("domain") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		(void) strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
		if ((cp = strchr(_res.defdname, '\n')) != NULL)
		    *cp = '\0';
		havesearch = 0;
		continue;
	    }
	    /* set search list */
	    if (!strncmp(buf, "search", sizeof("search") - 1)) {
		if (haveenv)	/* skip if have from environ */
		    continue;
		cp = buf + sizeof("search") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		(void) strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
		if ((cp = strchr(_res.defdname, '\n')) != NULL)
		    *cp = '\0';
		/*
		 * Set search list to be blank-separated strings on rest of
		 * line.
		 */
		cp = _res.defdname;
		pp = _res.dnsrch;
		*pp++ = cp;
		for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++)
		{
		    if (*cp == ' ' || *cp == '\t')
		    {
			*cp = 0;
			n = 1;
		    }
		    else if (n)
		    {
			*pp++ = cp;
			n = 0;
		    }
		}
		/* null terminate last domain if there are excess */
		while (*cp != '\0' && *cp != ' ' && *cp != '\t')
		    cp++;
		*cp = '\0';
		*pp++ = 0;
		havesearch = 1;
		continue;
	    }
	    /* read nameservers to query */
	    if (!strncmp(buf, "nameserver", sizeof("nameserver") - 1) &&
		nserv < MAXNS)
	    {
		cp = buf + sizeof("nameserver") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		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++;
		continue;
	    }
	    /* read service order */
	    if (!strncmp(buf, "order", sizeof("order") - 1))
	    {
		cp = buf + sizeof("order") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		norder = 0;
		do 
		{
		    if ((dp = strchr(cp, ',')) != NULL)
			*dp = '\0';
		    if (norder >= MAXSERVICES)
			continue;
		    if (!strncmp(cp, "bind", sizeof("bind") - 1))
			_res.order[norder++] = RES_SERVICE_BIND;
		    else if (!strncmp(cp, "local", sizeof("local") - 1))
			_res.order[norder++] = RES_SERVICE_LOCAL;
		    cp = dp + 1;
		} while (dp != NULL);
		_res.order[norder] = RES_SERVICE_NONE;
		continue;
	    }
	}
	if (nserv > 1)
	    _res.nscount = nserv;
	(void) fclose(fp);
    }
    if (_res.defdname[0] == 0)
    {
	if (gethostname(buf, sizeof(_res.defdname)) == 0 &&
	    (cp = strchr(buf, '.')))
	    (void) strcpy(_res.defdname, cp + 1);
    }
    
    /* find components of local domain that might be searched */
    if (havesearch == 0) 
    {
	pp = _res.dnsrch;
	*pp++ = _res.defdname;
	for (cp = _res.defdname, n = 0; *cp; cp++)
	    if (*cp == '.')
		n++;
	cp = _res.defdname;
	for (; n >= LOCALDOMAINPARTS && pp < _res.dnsrch + MAXDFLSRCH; n--)
	{
	    cp = strchr(cp, '.');
	    *pp++ = ++cp;
	}
	*pp++ = 0;
    }
    /* default search order to bind only */
    if (norder == 0) 
    {
	_res.order[0] = RES_SERVICE_BIND;
	_res.order[1] = RES_SERVICE_NONE;
    }
    _res.options |= RES_INIT;
    return (0);
}