[PATCH] iptables: fix error reporting for missing/wrong arguments

This patch fixes a confusing error reporting when some arguments are
missing or the option passed is unknown.

According to man getopt_long:
"If getopt() finds an option character in argv that was not
 included in optstring, or if it detects a missing option 
 argument, it returns '?' and sets the external variable
 optopt to the actual option character."

Without the patch:

% iptables -I INPUT -m state --whatever
iptables v1.4.2-rc1: Unknown arg `(null)

% iptables -I INPUT -m state --state
iptables v1.4.2-rc1: Unknown arg `(null)

With the patch:

% iptables -I INPUT -m state --whatever
iptables v1.4.2-rc1: unknown option `--whatever'
Try `iptables -h' or 'iptables --help' for more information.

% iptables -I INPUT -m state --state
iptables v1.4.2-rc1: option `--state' requires an argument
Try `iptables -h' or 'iptables --help' for more information.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/ip6tables.c b/ip6tables.c
index 12298ca..9ce1074 100644
--- a/ip6tables.c
+++ b/ip6tables.c
@@ -1888,9 +1888,26 @@ int do_command6(int argc, char *argv[], char **table, ip6tc_handle_t *handle)
 					continue;
 				}
 
-				if (!m)
+				if (!m) {
+					if (c == '?') {
+						if (optopt) {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "option `%s' "
+							   "requires an "
+							   "argument",
+							   argv[optind-1]);
+						} else {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "unknown option "
+							   "`%s'",
+							   argv[optind-1]);
+						}
+					}
 					exit_error(PARAMETER_PROBLEM,
 						   "Unknown arg `%s'", optarg);
+				}
 			}
 		}
 		invert = FALSE;
diff --git a/iptables.c b/iptables.c
index b927a11..d2b9081 100644
--- a/iptables.c
+++ b/iptables.c
@@ -1909,9 +1909,26 @@ int do_command(int argc, char *argv[], char **table, iptc_handle_t *handle)
 					optind--;
 					continue;
 				}
-				if (!m)
+				if (!m) {
+					if (c == '?') {
+						if (optopt) {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "option `%s' "
+							   "requires an "
+							   "argument",
+							   argv[optind-1]);
+						} else {
+							exit_error(
+							   PARAMETER_PROBLEM,
+							   "unknown option "
+							   "`%s'",
+							   argv[optind-1]);
+						}
+					}
 					exit_error(PARAMETER_PROBLEM,
 						   "Unknown arg `%s'", optarg);
+				}
 			}
 		}
 		invert = FALSE;