PHP中获得mac地址

<?php
class GetMacAddr {
	var $return_array = array();
	// 返回带有MAC地址的字串数组
	var $mac_addr = array();

	function GetMacAddr() {
		switch (strtolower(PHP_OS) ) {
			case "linux" :
				$this -> forLinux();
				break;
			case "solaris" :
				break;
			case "unix" :
				break;
			case "aix" :
				break;
			default :
				$this -> forWindows();
				break;
		}

		$temp_array = array();
		foreach ($this->return_array as $value) {
			if (preg_match("/[0-9a-f][0-9a-f][:-]" . "[0-9a-f][0-9a-f][:-]" . "[0-9a-f][0-9a-f][:-]" . "[0-9a-f][0-9a-f][:-]" . "[0-9a-f][0-9a-f][:-]" . "[0-9a-f][0-9a-f]/i", $value, $temp_array)) {
				$this -> mac_addr[] = $temp_array[0];
			}
		}
		unset($temp_array);
		return $this -> mac_addr;
	}

	function forWindows() {
		@exec("ipconfig /all", $this -> return_array);
		if ($this -> return_array)
			return $this -> return_array;
		else {
			$ipconfig = $_SERVER["WINDIR"] . "\system32\ipconfig.exe";
			if (is_file($ipconfig))
				@exec($ipconfig . " /all", $this -> return_array);
			else
				@exec($_SERVER["WINDIR"] . "\system\ipconfig.exe /all", $this -> return_array);
			return $this -> return_array;
		}
	}

	function forLinux() {
		@exec("ifconfig -a", $this -> return_array);
		return $this -> return_array;
	}

}

$mac = new GetMacAddr();
//var_dump($mac);
print_r($mac -> mac_addr);