acl_valid - validate an ACL
Check that the format of an ACL is valid.
First, aclp must be non null. The three required entries (ACL_USER_OBJ, ACL_GROUP_OBJ, and ACL_OTHER_OBJ) must exist exactly once in the ACL. If the ACL contains any ACL_USER, ACL_GROUP, or any implementationdefined entries in the file group class, then one ACL_MASK entry is required. The ACL may contain at most one ACL_MASK entry.
The qualifier field must be unique among all entries of the same type.
acl_valid returns 0 if the ACL is valid, 1 otherwise.
EINVAL ACL is not valid.