fatal() immediately whem parsing command line option '-c' reveals a non-existant

file.

Original diff, tweaks & ok kn@

3 files changed, 17 insertions, 21 deletions

diff --git a/sbin/dhclient/dhclient.8 b/sbin/dhclient/dhclient.8
index 875a6e7dcce..17cd6f2bc64 100644
--- a/sbin/dhclient/dhclient.8
+++ b/sbin/dhclient/dhclient.8
@@ -1,4 +1,4 @@
-.\" $OpenBSD: dhclient.8,v 1.44 2020/11/06 21:53:55 krw Exp $
+.\" $OpenBSD: dhclient.8,v 1.45 2020/12/06 17:40:43 krw Exp $
 .\"
 .\" Copyright (c) 1997 The Internet Software Consortium.
 .\" All rights reserved.
@@ -35,7 +35,7 @@
 .\" Enterprises.  To learn more about the Internet Software Consortium,
 .\" see ``http://www.isc.org/isc''.  To learn more about Vixie
 .\" Enterprises, see ``http://www.vix.com''.
-.Dd $Mdocdate: November 6 2020 $
+.Dd $Mdocdate: December 6 2020 $
 .Dt DHCLIENT 8
 .Os
 .Sh NAME
@@ -81,6 +81,9 @@ The options are as follows:
 Specify an alternate location to
 .Pa /etc/dhclient.conf
 for the configuration file.
+If
+.Ar file
+is the empty string then no configuration file is read.
 .It Fl d
 Do not daemonize.
 If this option is specified,
diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 3238da5a7b2..c9c0c2133b8 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhclient.c,v 1.688 2020/12/01 14:55:40 krw Exp $	*/
+/*	$OpenBSD: dhclient.c,v 1.689 2020/12/06 17:40:43 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -95,7 +95,7 @@
 #include "log.h"
 #include "privsep.h"
 
-char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
+char *path_dhclient_conf;
 char *path_lease_db;
 char *log_procname;
 
@@ -637,13 +637,18 @@ main(int argc, char *argv[])
 
 	log_setverbose(0);	/* Don't show log_debug() messages. */
 
+	if (lstat(_PATH_DHCLIENT_CONF, &sb) == 0)
+		path_dhclient_conf = _PATH_DHCLIENT_CONF;
+
 	while ((ch = getopt(argc, argv, "c:di:nrv")) != -1)
 		switch (ch) {
 		case 'c':
-			if (optarg == NULL)
-				usage();
-			cmd_opts |= OPT_CONFPATH;
-			path_dhclient_conf = optarg;
+			if (strlen(optarg) == 0)
+				path_dhclient_conf = NULL;
+			else if (lstat(optarg, &sb) == 0)
+				path_dhclient_conf = optarg;
+			else
+				fatal("lstat(%s)", optarg);
 			break;
 		case 'd':
 			cmd_opts |= OPT_FOREGROUND;
@@ -673,17 +678,6 @@ main(int argc, char *argv[])
 	if (argc != 1)
 		usage();
 
-	if ((cmd_opts & OPT_CONFPATH) != 0) {
-		if (lstat(path_dhclient_conf, &sb) == -1) {
-			/*
-			 * Non-existant file is OK. It lets you ignore
-			 * /etc/dhclient.conf for testing.
-			 */
-			if (errno != ENOENT)
-				fatal("lstat(%s)", path_dhclient_conf);
-		}
-	}
-
 	if ((cmd_opts & (OPT_FOREGROUND | OPT_NOACTION)) != 0)
 		cmd_opts |= OPT_VERBOSE;
 
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index 3d6fe046bc0..6db785d097d 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpd.h,v 1.288 2020/11/06 21:53:55 krw Exp $	*/
+/*	$OpenBSD: dhcpd.h,v 1.289 2020/12/06 17:40:43 krw Exp $	*/
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -215,7 +215,6 @@ extern int			 cmd_opts;
 #define		OPT_VERBOSE	0x02
 #define		OPT_FOREGROUND	0x04
 #define		OPT_RELEASE	0x08
-#define		OPT_CONFPATH	0x10
 #define		OPT_IGNORELIST	0x40
 
 void		 dhcpoffer(struct interface_info *, struct option_data *,