[PATCH v2] getopt: add support for non-option arguments

[Gianluca Anzolin <gianluca@sottospazio.it>]

Currently getopt() doesn't handle the GNU getopt extension that allows
to parse non-option arguments when optstring starts with '-'.

This extensions is used by some common utilities, notably iptables, that
currently return with errors even with perfectly valid invocations, for
example:

$ iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP

The patch add the code needed to implement this extension to getopt.c
and getopt_long.c

v2: do not add a second path to return getopt(...) to getopt_long.c

Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
---
 src/misc/getopt.c      | 17 ++++++++++++++++-
 src/misc/getopt_long.c |  7 ++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/misc/getopt.c b/src/misc/getopt.c
index f94c4f7..a698c8d 100644
--- a/src/misc/getopt.c
+++ b/src/misc/getopt.c
@@ -24,8 +24,20 @@ int getopt(int argc, char * const argv[], const char *optstring)
 		optind = 1;
 	}
 
-	if (optind >= argc || !argv[optind] || argv[optind][0] != '-' || !argv[optind][1])
+	if (optind >= argc || !argv[optind])
 		return -1;
+
+	if (argv[optind][0] != '-') {
+		if (optstring[0] == '-') {
+			optarg = argv[optind++];
+			return 1;
+		}
+		return -1;
+	}
+
+	if (!argv[optind][1])
+		return -1;
+
 	if (argv[optind][1] == '-' && !argv[optind][2])
 		return optind++, -1;
 
@@ -43,6 +55,9 @@ int getopt(int argc, char * const argv[], const char *optstring)
 		optpos = 0;
 	}
 
+	if (optstring[0] == '-')
+		optstring++;
+
 	for (i=0; (l = mbtowc(&d, optstring+i, MB_LEN_MAX)) && d!=c; i+=l>0?l:1);
 
 	if (d != c) {
diff --git a/src/misc/getopt_long.c b/src/misc/getopt_long.c
index 4ef5a5c..3d318ce 100644
--- a/src/misc/getopt_long.c
+++ b/src/misc/getopt_long.c
@@ -12,9 +12,10 @@ static int __getopt_long(int argc, char *const *argv, const char *optstring, con
 		__optpos = 0;
 		optind = 1;
 	}
-	if (optind >= argc || !argv[optind] || argv[optind][0] != '-') return -1;
-	if ((longonly && argv[optind][1]) ||
-		(argv[optind][1] == '-' && argv[optind][2]))
+	if (optind >= argc || !argv[optind]) return -1;
+	if (argv[optind][0] == '-' &&
+		((longonly && argv[optind][1]) ||
+		 (argv[optind][1] == '-' && argv[optind][2])))
 	{
 		int i;
 		for (i=0; longopts[i].name; i++) {
-- 
2.1.3