res_init.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* University Copyright- Copyright (c) 1982, 1986, 1988
* The Regents of the University of California
* All Rights Reserved
*
* University Acknowledgment- Portions of this document are derived from
* software developed by the University of California, Berkeley, and its
* contributors.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/types.h>
#include <sys/sockio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <netinet/in.h>
#include <net/if.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#define MAXIFS 256
/*
* 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_LOOPBACK and the default domain name comes from the gethostname().
* BUT if the NIS/RPC domain name is set, that is used if all else fails.
*
* The configuration file should only be used if you want to redefine your
* domain or run without a server on your machine.
*
* Note the user can always override then domain name with the environment
* variable LOCALDOMAIN which has absolute priority.
*
*
* Return 0 if completes successfully, -1 on error
*/
int
res_init(void)
{
register FILE *fp;
register char *cp, **pp;
register int n;
char buf[BUFSIZ];
#ifdef SYSV
extern char *strchr();
#else
extern char *index();
#endif
extern char *strcpy(), *strncpy();
extern char *getenv();
int nserv = 0; /* number of nameserver records read from file */
int haveenv = 0;
int havesearch = 0;
_res.nsaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); /* INADDR_ANY */
_res.nsaddr.sin_family = AF_INET;
_res.nsaddr.sin_port = htons(NAMESERVER_PORT);
_res.nscount = 1;
#ifdef SIOCGIFNUM
{ int numifs, s, n, int_up;
struct ifconf ifc;
register struct ifreq *ifrp;
struct ifreq ifr;
unsigned bufsize;
unsigned int flags;
char *buf;
extern void *malloc();
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("socket");
return (-1);
}
if (ioctl(s, SIOCGIFNUM, (char *)&numifs) < 0) {
numifs = MAXIFS;
}
bufsize = numifs * sizeof (struct ifreq);
buf = (char *)malloc(bufsize);
if (buf == NULL) {
perror("out of memory");
close(s);
return (-1);
}
ifc.ifc_len = bufsize;
ifc.ifc_buf = buf;
if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
perror("ifconfig: SIOCGIFCONF");
close(s);
free(buf);
return (-1);
}
int_up = 0;
ifrp = ifc.ifc_req;
for (n = ifc.ifc_len / sizeof (struct ifreq); n > 0;
n--, ifrp++) {
memset((void *) &ifr, 0, sizeof (ifr));
strncpy(ifr.ifr_name, ifrp->ifr_name,
sizeof (ifr.ifr_name));
if (ioctl(s, SIOCGIFFLAGS, (char *)&ifr) < 0) {
perror("SIOCGIFFLAGS");
close(s);
free(buf);
return (-1);
}
flags = ifr.ifr_flags;
/* we are looking for a non-loopback interface */
if ((flags & IFF_UP) && ((flags & IFF_LOOPBACK) == 0))
int_up = 1;
}
close(s);
free(buf);
if (int_up == 0) /* all the non-LOOPBACK interfaces are DOWN */
return (-1);
}
#endif /* SIOCGIFNUM */
/*
* for the benefit of hidden NIS domains, we use the same procedure
* as sendmail: convert leading + to dot, then drop to first dot
*/
getdomainname(buf, BUFSIZ);
if (buf[0] == '+')
buf[0] = '.';
#ifdef SYSV
cp = strchr(buf, (int)'.');
#else
cp = index(buf, '.');
#endif
if (cp == NULL)
strcpy(_res.defdname, buf);
else
strcpy(_res.defdname, cp+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);
#ifdef SYSV
if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
#else
if ((cp = index(_res.defdname, '\n')) != NULL)
#endif
*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);
#ifdef SYSV
if ((cp = strchr(_res.defdname, (int)'\n')) != NULL)
#else
if ((cp = index(_res.defdname, '\n')) != NULL)
#endif
*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[n].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;
}
}
if (nserv > 1)
_res.nscount = nserv;
(void) fclose(fp);
}
if (_res.defdname[0] == 0) {
if (gethostname(buf, sizeof (_res.defdname)) == 0 &&
#ifdef SYSV
(cp = strchr(buf, (int)'.')))
#else
(cp = index(buf, '.')))
#endif
(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--) {
#ifdef SYSV
cp = strchr(cp, (int)'.');
#else
cp = index(cp, '.');
#endif
*pp++ = ++cp;
}
*pp++ = 0;
}
_res.options |= RES_INIT;
return (0);
}