cfgfile: check flags on creation for future proofing

All API's should check that they support the flag values
passed. If an application passes an invalid flag it could
cause problems in later ABI.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

lib/librte_cfgfile/rte_cfgfile.c

@@ -272,6 +272,10 @@ rte_cfgfile_create(int flags)
 	int i;
 	struct rte_cfgfile *cfg;
 
+	/* future proof flags usage */
+	if (flags & ~(CFG_FLAG_GLOBAL_SECTION | CFG_FLAG_EMPTY_VALUES))
+		return NULL;
+
 	cfg = malloc(sizeof(*cfg));
 
 	if (cfg == NULL)