The clang-tidy program is complaining about a potential null pointer
dereference where none is possible. To convince it of that fact, I've
added a redundant equality check: we have a case where (a == b) and (a
== c), and I've added (b == c) explicitly. This fixes the warning, and
should have very little performance impact, so everyone is happy.
- /* Otherwise, we have to have matching UIDs or GIDs. */
- if (updated_tag == ACL_USER) {
+ /* Second, they could have matching UIDs. We don't really need to
+ check both tags here, since we know that they're equal. However,
+ clang-tidy can't figure that out, and the redundant equality
+ check prevents it from complaining about a potential null pointer
+ dereference. */
+ if (updated_tag == ACL_USER && existing_tag == ACL_USER) {
qualifiers_match = ( *((uid_t*)existing_qualifier)
==
*((uid_t*)updated_qualifier) );
}
qualifiers_match = ( *((uid_t*)existing_qualifier)
==
*((uid_t*)updated_qualifier) );
}
- else if (updated_tag == ACL_GROUP) {
+
+ /* Third, they could have matching GIDs. See above for why
+ we check the redundant condition existing_tag == ACL_GROUP. */
+ if (updated_tag == ACL_GROUP && existing_tag == ACL_GROUP) {
qualifiers_match = ( *((gid_t*)existing_qualifier)
==
*((gid_t*)updated_qualifier) );
qualifiers_match = ( *((gid_t*)existing_qualifier)
==
*((gid_t*)updated_qualifier) );