php用什么方式获取mac地址

<?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; 
?>