[musl] [PATCH] fix error handling in getsubopt()

[Marian Buschsieweke <marian.buschsieweke@ovgu.de>]

The man page of getsubopt says

>    int getsubopt(char **restrict optionp, char *const *restrict tokens,
>                  char **restrict valuep);
>
> [...]
> RETURN VALUE
>       If the first suboption in optionp is recognized, getsubopt()
>       returns the index of the matching suboption element in tokens.
>       Otherwise, -1 is returned and *valuep is the entire name[=value]
>       string.

This means, *val should be set to the value *opt had upon the call of
getsubopt on failure, but this is not the case. This fixes the behavior.

This fixes a segmentation fault in the option parsing in v4l2-ctl for the
-c parameter. (E.g. v4l2-ctl -c foo=bar will segfault without this.)
---
 src/misc/getsubopt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/misc/getsubopt.c b/src/misc/getsubopt.c
index 53ee9573..37cca186 100644
--- a/src/misc/getsubopt.c
+++ b/src/misc/getsubopt.c
@@ -19,5 +19,6 @@ int getsubopt(char **opt, char *const *keys, char **val)
 		else if (s[l]) continue;
 		return i;
 	}
+	*val = s;
 	return -1;
 }
-- 
2.33.1