minix/lib/ip/res_init.c

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2005-04-21 16:53:53 +02:00
/*-
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_init.c 6.14 (Berkeley) 6/27/90";
#endif /* LIBC_SCCS and not lint */
#if _MINIX
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/hton.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/nameser.h>
#include <net/gen/netdb.h>
#include <net/gen/resolv.h>
#include <net/gen/socket.h>
#define index(s,c) strchr(s,c)
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <arpa/nameser.h>
#include <resolv.h>
#endif
/*
* Resolver state
*/
struct state _res;
/*
* Set up default settings. If the configuration file exist, the values
* there will have precedence. Otherwise, the server address is set to
* 127.0.0.1 (localhost) and the default domain name comes from 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()
{
register FILE *fp;
register char *cp, **pp;
register int n;
char buf[BUFSIZ];
int haveenv = 0;
int havesearch = 0;
struct servent* servent;
u16_t nameserver_port;
/* Resolver state default settings */
_res.retrans = RES_TIMEOUT; /* retransmition time interval */
_res.retry = 4; /* number of times to retransmit */
_res.options = RES_DEFAULT; /* options flags */
_res.nscount = 0; /* number of name servers */
_res.defdname[0] = 0; /* domain */
servent= getservbyname("domain", NULL);
if (!servent)
{
h_errno= NO_RECOVERY;
return -1;
}
nameserver_port= servent->s_port;
/* 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 = index(_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 = index(_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) &&
_res.nscount < MAXNS) {
cp = buf + sizeof("nameserver") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
if (!inet_aton(cp, &_res.nsaddr_list[_res.nscount]))
continue;
_res.nsport_list[_res.nscount]= nameserver_port;
_res.nscount++;
continue;
}
}
(void) fclose(fp);
}
if (_res.nscount == 0) {
/* "localhost" is the default nameserver. */
_res.nsaddr_list[0]= HTONL(0x7F000001);
_res.nsport_list[0]= nameserver_port;
_res.nscount= 1;
}
if (_res.defdname[0] == 0) {
if (gethostname(buf, sizeof(_res.defdname)) == 0 &&
(cp = index(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 = index(cp, '.');
*pp++ = ++cp;
}
*pp++ = 0;
}
_res.options |= RES_INIT;
return (0);
}