text: // Package operatingsystem provides helper function to get the operating system
  // name for different platforms.
  package operatingsystem
  
  import (
  	"bufio"
  	"bytes"
  	"fmt"
  	"io/ioutil"
  	"os"
  	"strings"
  
  	"github.com/mattn/go-shellwords"
  )
  
  var (
  	// file to use to detect if the daemon is running in a container
  	proc1Cgroup = "/proc/1/cgroup"
  
  	// file to check to determine Operating System
  	etcOsRelease = "/etc/os-release"
  
  	// used by stateless systems like Clear Linux
  	altOsRelease = "/usr/lib/os-release"
  )
  
  // GetOperatingSystem gets the name of the current operating system.
  func GetOperatingSystem() (string, error) {
  	osReleaseFile, err := os.Open(etcOsRelease)
  	if err != nil {
  		if !os.IsNotExist(err) {
  			return "", fmt.Errorf("Error opening %s: %v", etcOsRelease, err)
  		}
  		osReleaseFile, err = os.Open(altOsRelease)
  		if err != nil {
  			return "", fmt.Errorf("Error opening %s: %v", altOsRelease, err)
  		}
  	}
  	defer osReleaseFile.Close()
  
  	var prettyName string
  	scanner := bufio.NewScanner(osReleaseFile)
  	for scanner.Scan() {
  		line := scanner.Text()
  		if strings.HasPrefix(line, "PRETTY_NAME=") {
  			data := strings.SplitN(line, "=", 2)
  			prettyNames, err := shellwords.Parse(data[1])
  			if err != nil {
  				return "", fmt.Errorf("PRETTY_NAME is invalid: %s", err.Error())
  			}
  			if len(prettyNames) != 1 {
  				return "", fmt.Errorf("PRETTY_NAME needs to be enclosed by quotes if they have spaces: %s", data[1])
  			}
  			prettyName = prettyNames[0]
  		}
  	}
  	if prettyName != "" {
  		return prettyName, nil
  	}
  	// If not set, defaults to PRETTY_NAME="Linux"
  	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
  	return "Linux", nil
  }
  
  // IsContainerized returns true if we are running inside a container.
  func IsContainerized() (bool, error) {
  	b, err := ioutil.ReadFile(proc1Cgroup)
  	if err != nil {
  		return false, err
  	}
  	for _, line := range bytes.Split(b, []byte{'\n'}) {
  		if len(line) > 0 && !bytes.HasSuffix(line, []byte{'/'}) && !bytes.HasSuffix(line, []byte("init.scope")) {
  			return true, nil
  		}
  	}
  	return false, nil
  }
  