function login($username, $password){
                        global $REQUIRED_USER_GROUP, $OVERRIDE_UID;
                        if(!is_string($username) || !is_string($password)){
                                        print "Invalid username or password format";
                                        return false;
                        }
                        $user_details = posix_getpwnam($username);
                        if($user_details === FALSE){
                                print "User was not found";
                                return false;
                        }
                        if(!is_int($user_details['uid'])){
                                print "Invalid UID";
                                return false;
                        }
                        if($user_details['uid'] !== $OVERRIDE_UID){
                                // They don't have the override uid, check the group
                                $required_user_group_info = posix_getgrnam($REQUIRED_USER_GROUP);
                                if($required_user_group_info === FALSE){
                                        print "Could not get required group info";
                                        return false;
                                }
                                if(!in_array($username, $required_user_group_info['members'])){
                                        print "User '" . $username . "' not in the '" . $REQUIRED_USER_GROUP . "' group";
                                        return false;
                                }
                        }
                        // If we get to here they are either uid matching OVERRIDE_UID or in the group REQUIRED_USER_GROUP
                        if(pam_auth($username, $password, FALSE, FALSE) === TRUE){ // Check password only
                                print "User and pass match unix";
                                return true;
                        }else{
                                print "Could not match username and password";
                                return false;
                        }
        }