Add 'uselease' statement to allow the disabling of built-in or

previously specified 'append', 'default', 'ignore', 'prepend', or
'supersede' actions on the values provided in leases.

4 files changed, 52 insertions, 6 deletions

diff --git a/sbin/dhclient/clparse.c b/sbin/dhclient/clparse.c
index af4042aec2a..fc77de4bf9d 100644
--- a/sbin/dhclient/clparse.c
+++ b/sbin/dhclient/clparse.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clparse.c,v 1.180 2019/01/18 02:16:31 krw Exp $	*/
+/*	$OpenBSD: clparse.c,v 1.181 2019/01/26 22:55:10 krw Exp $	*/
 
 /* Parser for dhclient config and lease files. */
 
@@ -333,6 +333,29 @@ parse_conf_decl(FILE *cfile, char *name)
 		if (parse_ip_addr(cfile, &config->next_server) == 1)
 			parse_semi(cfile);
 		break;
+	case TOK_NOACTION:
+		memset(list, 0, sizeof(list));
+		count = 0;
+		if (parse_option_list(cfile, &count, list) == 1) {
+			enum actions *p = config->default_actions;
+			if (count == 0) {
+				for (i = 0; i < DHO_COUNT; i++) {
+					free(config->defaults[i].data);
+					config->defaults[i].data = NULL;
+					config->defaults[i].len = 0;
+					p[i] = ACTION_NONE;
+				}
+			} else {
+				for (i = 0; i < count; i++) {
+					free(config->defaults[list[i]].data);
+					config->defaults[list[i]].data = NULL;
+					config->defaults[list[i]].len = 0;
+					p[list[i]] = ACTION_NONE;
+				}
+			}
+			parse_semi(cfile);
+		}
+		break;
 	case TOK_PREPEND:
 		if (parse_option(cfile, &i, config->defaults) == 1) {
 			config->default_actions[i] = ACTION_PREPEND;
diff --git a/sbin/dhclient/conflex.c b/sbin/dhclient/conflex.c
index 2d97346e4aa..0ca5e1eeb76 100644
--- a/sbin/dhclient/conflex.c
+++ b/sbin/dhclient/conflex.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conflex.c,v 1.48 2017/11/06 13:27:19 krw Exp $	*/
+/*	$OpenBSD: conflex.c,v 1.49 2019/01/26 22:55:10 krw Exp $	*/
 
 /* Lexical scanner for dhclient config file. */
 
@@ -381,7 +381,8 @@ static const struct keywords {
 	{ "server-name",			TOK_SERVER_NAME },
 	{ "ssid",				TOK_SSID },
 	{ "supersede",				TOK_SUPERSEDE },
-	{ "timeout",				TOK_TIMEOUT }
+	{ "timeout",				TOK_TIMEOUT },
+	{ "uselease",				TOK_NOACTION }
 };
 
 int	kw_cmp(const void *k, const void *e);
diff --git a/sbin/dhclient/dhclient.conf.5 b/sbin/dhclient/dhclient.conf.5
index feddf48971a..8f3b701d956 100644
--- a/sbin/dhclient/dhclient.conf.5
+++ b/sbin/dhclient/dhclient.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: dhclient.conf.5,v 1.44 2018/05/12 12:50:17 krw Exp $
+.\"	$OpenBSD: dhclient.conf.5,v 1.45 2019/01/26 22:55:10 krw Exp $
 .\"
 .\" Copyright (c) 1997 The Internet Software Consortium.
 .\" All rights reserved.
@@ -36,7 +36,7 @@
 .\" see ``http://www.isc.org/isc''.  To learn more about Vixie
 .\" Enterprises, see ``http://www.vix.com''.
 .\"
-.Dd $Mdocdate: May 12 2018 $
+.Dd $Mdocdate: January 26 2019 $
 .Dt DHCLIENT.CONF 5
 .Os
 .Sh NAME
@@ -216,6 +216,27 @@ or
 .Ic supersede
 for
 .Ar option .
+.It Ic uselease Op Ar option , ... ;
+Use the unmodified values provided in the lease for
+any specified
+.Ar option .
+.Ic uselease
+statements are cumulative.
+If no
+.Ar option
+is specified all lease option values will be used unmodified.
+.Ic uselease
+for
+.Ar option
+overrides any previous
+.Ic append ,
+.Ic default ,
+.Ic ignore ,
+.Ic prepend
+or
+.Ic supersede
+for
+.Ar option .
 .El
 .Sh OTHER DECLARATIONS
 .Bl -tag -width Ds
diff --git a/sbin/dhclient/dhctoken.h b/sbin/dhclient/dhctoken.h
index cdf39ebbbcb..bef9cf9a070 100644
--- a/sbin/dhclient/dhctoken.h
+++ b/sbin/dhclient/dhctoken.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhctoken.h,v 1.14 2017/11/06 13:27:19 krw Exp $	*/
+/*	$OpenBSD: dhctoken.h,v 1.15 2019/01/26 22:55:10 krw Exp $	*/
 
 /* Tokens for config file lexer and parser. */
 
@@ -74,6 +74,7 @@
 #define TOK_IGNORE		295
 #define TOK_SSID		296
 #define TOK_EPOCH		297
+#define TOK_NOACTION		298
 
 #define is_identifier(x)	((x) >= TOK_FIRST_TOKEN &&	\
     (x) != TOK_STRING &&					\