213 lines
6.1 KiB
C
213 lines
6.1 KiB
C
/* resolv.c
|
|
|
|
Parser for /etc/resolv.conf file. */
|
|
|
|
/*
|
|
* Copyright (c) 1996-2001 Internet Software Consortium.
|
|
* 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. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
|
|
*
|
|
* This software has been written for the Internet Software Consortium
|
|
* by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
|
|
* To learn more about the Internet Software Consortium, see
|
|
* ``http://www.isc.org/''. To learn more about Vixie Enterprises,
|
|
* see ``http://www.vix.com''. To learn more about Nominum, Inc., see
|
|
* ``http://www.nominum.com''.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char copyright[] =
|
|
"$Id: resolv.c,v 1.16 2001/05/02 06:39:43 mellon Exp $ Copyright (c) 1996-2001 The Internet Software Consortium. All rights reserved.\n";
|
|
#endif /* not lint */
|
|
|
|
#include "dhcpd.h"
|
|
|
|
struct name_server *name_servers;
|
|
struct domain_search_list *domains;
|
|
char path_resolv_conf [] = _PATH_RESOLV_CONF;
|
|
|
|
void read_resolv_conf (parse_time)
|
|
TIME parse_time;
|
|
{
|
|
int file;
|
|
struct parse *cfile;
|
|
const char *val;
|
|
int token;
|
|
int declaration = 0;
|
|
struct name_server *sp, *sl, *ns;
|
|
struct domain_search_list *dp, *dl, *nd;
|
|
struct iaddr *iaddr;
|
|
|
|
if ((file = open (path_resolv_conf, O_RDONLY)) < 0) {
|
|
log_error ("Can't open %s: %m", path_resolv_conf);
|
|
return;
|
|
}
|
|
|
|
cfile = (struct parse *)0;
|
|
new_parse (&cfile, file, (char *)0, 0, path_resolv_conf, 1);
|
|
|
|
do {
|
|
token = next_token (&val, (unsigned *)0, cfile);
|
|
if (token == END_OF_FILE)
|
|
break;
|
|
else if (token == EOL)
|
|
continue;
|
|
else if (token == DOMAIN || token == SEARCH) {
|
|
do {
|
|
struct domain_search_list *nd, **dp;
|
|
char *dn;
|
|
|
|
dn = parse_host_name (cfile);
|
|
if (!dn)
|
|
break;
|
|
|
|
dp = &domains;
|
|
for (nd = domains; nd; nd = nd -> next) {
|
|
dp = &nd -> next;
|
|
if (!strcmp (nd -> domain, dn))
|
|
break;
|
|
}
|
|
if (!nd) {
|
|
nd = new_domain_search_list (MDL);
|
|
if (!nd)
|
|
log_fatal ("No memory for %s",
|
|
dn);
|
|
nd -> next =
|
|
(struct domain_search_list *)0;
|
|
*dp = nd;
|
|
nd -> domain = dn;
|
|
dn = (char *)0;
|
|
}
|
|
nd -> rcdate = parse_time;
|
|
token = peek_token (&val,
|
|
(unsigned *)0, cfile);
|
|
} while (token != EOL);
|
|
if (token != EOL) {
|
|
parse_warn (cfile,
|
|
"junk after domain declaration");
|
|
skip_to_semi (cfile);
|
|
}
|
|
token = next_token (&val, (unsigned *)0, cfile);
|
|
} else if (token == NAMESERVER) {
|
|
struct name_server *ns, **sp;
|
|
struct iaddr iaddr;
|
|
|
|
parse_ip_addr (cfile, &iaddr);
|
|
|
|
sp = &name_servers;
|
|
for (ns = name_servers; ns; ns = ns -> next) {
|
|
sp = &ns -> next;
|
|
if (!memcmp (&ns -> addr.sin_addr,
|
|
iaddr.iabuf, iaddr.len))
|
|
break;
|
|
}
|
|
if (!ns) {
|
|
ns = new_name_server (MDL);
|
|
if (!ns)
|
|
log_fatal ("No memory for nameserver %s",
|
|
piaddr (iaddr));
|
|
ns -> next = (struct name_server *)0;
|
|
*sp = ns;
|
|
memcpy (&ns -> addr.sin_addr,
|
|
iaddr.iabuf, iaddr.len);
|
|
#ifdef HAVE_SA_LEN
|
|
ns -> addr.sin_len = sizeof ns -> addr;
|
|
#endif
|
|
ns -> addr.sin_family = AF_INET;
|
|
ns -> addr.sin_port = htons (53);
|
|
memset (ns -> addr.sin_zero, 0,
|
|
sizeof ns -> addr.sin_zero);
|
|
}
|
|
ns -> rcdate = parse_time;
|
|
skip_to_semi (cfile);
|
|
} else
|
|
skip_to_semi (cfile); /* Ignore what we don't grok. */
|
|
} while (1);
|
|
token = next_token (&val, (unsigned *)0, cfile);
|
|
|
|
/* Lose servers that are no longer in /etc/resolv.conf. */
|
|
sl = (struct name_server *)0;
|
|
for (sp = name_servers; sp; sp = ns) {
|
|
ns = sp -> next;
|
|
if (sp -> rcdate != parse_time) {
|
|
if (sl)
|
|
sl -> next = sp -> next;
|
|
else
|
|
name_servers = sp -> next;
|
|
/* We can't actually free the name server structure,
|
|
because somebody might be hanging on to it. If
|
|
your /etc/resolv.conf file changes a lot, this
|
|
could be a noticable memory leak. */
|
|
} else
|
|
sl = sp;
|
|
}
|
|
|
|
/* Lose domains that are no longer in /etc/resolv.conf. */
|
|
dl = (struct domain_search_list *)0;
|
|
for (dp = domains; dp; dp = nd) {
|
|
nd = dp -> next;
|
|
if (dp -> rcdate != parse_time) {
|
|
if (dl)
|
|
dl -> next = dp -> next;
|
|
else
|
|
domains = dp -> next;
|
|
free_domain_search_list (dp, MDL);
|
|
} else
|
|
dl = dp;
|
|
}
|
|
close (file);
|
|
end_parse (&cfile);
|
|
}
|
|
|
|
/* Pick a name server from the /etc/resolv.conf file. */
|
|
|
|
struct name_server *first_name_server ()
|
|
{
|
|
FILE *rc;
|
|
static TIME rcdate;
|
|
struct stat st;
|
|
|
|
/* Check /etc/resolv.conf and reload it if it's changed. */
|
|
if (cur_time > rcdate) {
|
|
if (stat (path_resolv_conf, &st) < 0) {
|
|
log_error ("Can't stat %s", path_resolv_conf);
|
|
return (struct name_server *)0;
|
|
}
|
|
if (st.st_mtime > rcdate) {
|
|
char rcbuf [512];
|
|
char *s, *t, *u;
|
|
rcdate = cur_time + 1;
|
|
|
|
read_resolv_conf (rcdate);
|
|
}
|
|
}
|
|
|
|
return name_servers;
|
|
}
|