Aerys\Server::dropPrivileges PHP Method

    private function dropPrivileges()
    {
        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
            return;
        }
        $user = $this->options->user;
        if (!extension_loaded("posix")) {
            if ($user !== null) {
                throw new \RuntimeException("Posix extension must be enabled to switch to user '{$user}'!");
            } else {
                $this->logger->warning("Posix extension not enabled, be sure not to run your server as root!");
            }
        } elseif (posix_geteuid() === 0) {
            if ($user === null) {
                $this->logger->warning("Running as privileged user is discouraged! Use the 'user' option to switch to another user after startup!");
                return;
            }
            $info = posix_getpwnam($user);
            if (!$info) {
                throw new \RuntimeException("Switching to user '{$user}' failed, because it doesn't exist!");
            }
            $success = posix_seteuid($info["uid"]);
            if (!$success) {
                throw new \RuntimeException("Switching to user '{$user}' failed, probably because of missing privileges.'");
            }
        }
    }