Proper fix for "unknown argument" error message

While commit 1b8210f848631 kind of fixed the corner-case of invalid
short-options packed with others, it broke error reporting for
long-options. Revert it and deploy a proper solution:

When passing an invalid short-option, e.g. 'iptables -vaL', getopt_long
sets the variable 'optopt' to the invalid character's value. Use it for
reporting instead of optind if set.

To distinguish between invalid options and missing option arguments,
ebtables-translate optstring needs adjustment.

Fixes: 1b8210f848631 ("ebtables: Fix error message for invalid parameters")
Signed-off-by: Phil Sutter <phil@nwl.cc>

1 files changed, 31 insertions, 0 deletions

diff --git a/iptables/tests/shell/testcases/iptables/0009-unknown-arg_0 b/iptables/tests/shell/testcases/iptables/0009-unknown-arg_0
new file mode 100755
index 00000000..ac6e7439
--- /dev/null
+++ b/iptables/tests/shell/testcases/iptables/0009-unknown-arg_0
@@ -0,0 +1,31 @@
+#!/bin/bash
+
+rc=0
+
+check() {
+	local cmd="$1"
+	local msg="$2"
+
+	$XT_MULTI $cmd 2>&1 | grep -q "$msg" || {
+		echo "cmd: $XT_MULTI $1"
+		echo "exp: $msg"
+		echo "res: $($XT_MULTI $cmd 2>&1)"
+		rc=1
+	}
+}
+
+cmds="iptables ip6tables"
+[[ $XT_MULTI == *xtables-nft-multi ]] && {
+	cmds+=" ebtables"
+	cmds+=" iptables-translate"
+	cmds+=" ip6tables-translate"
+	cmds+=" ebtables-translate"
+}
+
+for cmd in $cmds; do
+	check "${cmd} --foo" 'unknown option "--foo"'
+	check "${cmd} -A" 'option "-A" requires an argument'
+	check "${cmd} -aL" 'unknown option "-a"'
+done
+
+exit $rc