util: Don't stop on unrelated values when looking for --fd in close_open_files()

Seen with krun: we get a file descriptor via --fd, but we close it and
happily use the same number for TCP files.

The issue is that if we also get other options before --fd, with
arguments, getopt_long() stops parsing them because it sees them as
non-option values.

Use the - modifier at the beginning of optstring (before :, which is
needed to avoid printing errors) instead of +, which means we'll
continue parsing after finding unrelated option values, but
getopt_long() won't reorder them anyway: they'll be passed with option
value '1', which we can ignore.

By the way, we also need to add : after F in the optstring, so that
we're able to parse the option when given as short name as well.

Now that we change the parsing mode between close_open_files() and
conf(), we need to reset optind to 0, not to 1, whenever we call
getopt_long() again in conf(), so that the internal initialisation
of getopt_long() evaluating GNU extensions is re-triggered.

Link: https://github.com/slp/krun/issues/17#issuecomment-2294943828
Fixes: baccfb95ce0e ("conf: Stop parsing options at first non-option argument")
Fixes: 09603cab28f9 ("passt, util: Close any open file that the parent might have leaked")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 1 insertions, 1 deletions

diff --git a/util.c b/util.c
index f9f8113..6e64279 100644
--- a/util.c
+++ b/util.c
@@ -728,7 +728,7 @@ void close_open_files(int argc, char **argv)
 	int name, rc;
 
 	do {
-		name = getopt_long(argc, argv, "+:F", optfd, NULL);
+		name = getopt_long(argc, argv, "-:F:", optfd, NULL);
 
 		if (name == 'F') {
 			errno = 0;