3 Parser for /etc/resolv.conf file. */
6 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
7 * Copyright (c) 1996-2003 by Internet Software Consortium
9 * Permission to use, copy, modify, and distribute this software for any
10 * purpose with or without fee is hereby granted, provided that the above
11 * copyright notice and this permission notice appear in all copies.
13 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
14 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
16 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
19 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
21 * Internet Systems Consortium, Inc.
23 * Redwood City, CA 94063
27 * This software has been written for Internet Systems Consortium
28 * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
29 * To learn more about Internet Systems Consortium, see
30 * ``http://www.isc.org/''. To learn more about Vixie Enterprises,
31 * see ``http://www.vix.com''. To learn more about Nominum, Inc., see
32 * ``http://www.nominum.com''.
36 static char copyright
[] =
37 "$Id$ Copyright (c) 2004 Internet Systems Consortium. All rights reserved.\n";
42 struct name_server
*name_servers
;
43 struct domain_search_list
*domains
;
44 char path_resolv_conf
[] = _PATH_RESOLV_CONF
;
46 void read_resolv_conf (parse_time
)
53 // int declaration = 0;
54 struct name_server
*sp
, *sl
, *ns
;
55 struct domain_search_list
*dp
, *dl
, *nd
;
56 // struct iaddr *iaddr;
58 if ((file
= open (path_resolv_conf
, O_RDONLY
)) < 0) {
59 log_error ("Can't open %s: %m", path_resolv_conf
);
63 cfile
= (struct parse
*)0;
64 new_parse (&cfile
, file
, (char *)0, 0, path_resolv_conf
, 1);
67 token
= next_token (&val
, (unsigned *)0, cfile
);
68 if (token
== END_OF_FILE
)
70 else if (token
== EOL
)
72 else if (token
== DOMAIN
|| token
== SEARCH
) {
74 struct domain_search_list
*nd
, **dp
;
77 dn
= parse_host_name (cfile
);
82 for (nd
= domains
; nd
; nd
= nd
-> next
) {
84 if (!strcmp (nd
-> domain
, dn
))
88 nd
= new_domain_search_list (MDL
);
90 log_fatal ("No memory for %s",
93 (struct domain_search_list
*)0;
98 nd
-> rcdate
= parse_time
;
99 token
= peek_token (&val
,
100 (unsigned *)0, cfile
);
101 } while (token
!= EOL
);
104 "junk after domain declaration");
105 skip_to_semi (cfile
);
107 token
= next_token (&val
, (unsigned *)0, cfile
);
108 } else if (token
== NAMESERVER
) {
109 struct name_server
*ns
, **sp
;
112 parse_ip_addr (cfile
, &iaddr
);
115 for (ns
= name_servers
; ns
; ns
= ns
-> next
) {
117 if (!memcmp (&ns
-> addr
.sin_addr
,
118 iaddr
.iabuf
, iaddr
.len
))
122 ns
= new_name_server (MDL
);
124 log_fatal ("No memory for nameserver %s",
126 ns
-> next
= (struct name_server
*)0;
128 memcpy (&ns
-> addr
.sin_addr
,
129 iaddr
.iabuf
, iaddr
.len
);
131 ns
-> addr
.sin_len
= sizeof ns
-> addr
;
133 ns
-> addr
.sin_family
= AF_INET
;
134 ns
-> addr
.sin_port
= htons (53);
135 memset (ns
-> addr
.sin_zero
, 0,
136 sizeof ns
-> addr
.sin_zero
);
138 ns
-> rcdate
= parse_time
;
139 skip_to_semi (cfile
);
141 skip_to_semi (cfile
); /* Ignore what we don't grok. */
143 token
= next_token (&val
, (unsigned *)0, cfile
);
145 /* Lose servers that are no longer in /etc/resolv.conf. */
146 sl
= (struct name_server
*)0;
147 for (sp
= name_servers
; sp
; sp
= ns
) {
149 if (sp
-> rcdate
!= parse_time
) {
151 sl
-> next
= sp
-> next
;
153 name_servers
= sp
-> next
;
154 /* We can't actually free the name server structure,
155 because somebody might be hanging on to it. If
156 your /etc/resolv.conf file changes a lot, this
157 could be a noticable memory leak. */
162 /* Lose domains that are no longer in /etc/resolv.conf. */
163 dl
= (struct domain_search_list
*)0;
164 for (dp
= domains
; dp
; dp
= nd
) {
166 if (dp
-> rcdate
!= parse_time
) {
168 dl
-> next
= dp
-> next
;
170 domains
= dp
-> next
;
171 free_domain_search_list (dp
, MDL
);
179 /* Pick a name server from the /etc/resolv.conf file. */
181 struct name_server
*first_name_server ()
187 /* Check /etc/resolv.conf and reload it if it's changed. */
188 if (cur_time
> rcdate
) {
189 if (stat (path_resolv_conf
, &st
) < 0) {
190 log_error ("Can't stat %s", path_resolv_conf
);
191 return (struct name_server
*)0;
193 if (st
.st_mtime
> rcdate
) {
196 rcdate
= cur_time
+ 1;
198 read_resolv_conf (rcdate
);