php程序获取客户端MAC地址 何苦

<?php

/**
 * 获取网卡的MAC地址原码；目前支持WIN/LINUX系统
 * 获取机器网卡的物理（MAC）地址
 **/
class GetMacAddr
{
    var $return_array = array(); // 返回带有MAC地址的字串数组
    var $mac_addr;

    function GetMacAddr($os_type)
    {
        switch (strtolower($os_type)) {
            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 = $temp_array[0];
                break;
            }
        }
        unset($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;
    }
}

//方法使用
$mac = new GetMacAddr(PHP_OS);
echo $mac->mac_addr;
?>