util: document why parse_uid() returns ENXIO

parse_uid() returns EINVAL for invalid strings, but ENXIO for the (uid_t) -1 user ids in order to distinguish these two cases. Document this.
2015-09-04 09:07:31 +02:00
parent b3ac818be8
commit ef5c570edf
2 changed files with 7 additions and 1 deletions
@@ -403,7 +403,10 @@ int parse_uid(const char *s, uid_t* ret_uid) {
                return -ERANGE;

        if (!uid_is_valid(uid))
-                return -ENXIO;
+                return -ENXIO; /* we return ENXIO instead of EINVAL
+                                * here, to make it easy to distuingish
+                                * invalid numeric uids invalid
+                                * strings. */

        if (ret_uid)
                *ret_uid = uid;