config

var BackupConfigFile = func(filename string) error {
	return os.Rename(filename, filename+".bak")
}

var ReadConfigFile = func(filename string) ([]byte, error) {
	f, err := os.Open(filename)
	if err != nil {
		return nil, pathError(err)
	}
	defer f.Close()

	data, err := ioutil.ReadAll(f)
	if err != nil {
		return nil, err
	}

	return data, nil
}

var WriteConfigFile = func(filename string, data []byte) error {
	err := os.MkdirAll(path.Dir(filename), 0771)
	if err != nil {
		return pathError(err)
	}

	cfgFile, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		return err
	}
	defer cfgFile.Close()

	n, err := cfgFile.Write(data)
	if err == nil && n < len(data) {
		err = io.ErrShortWrite
	}

	return err
}