github.com/lacework-dev/go-moby@v20.10.12+incompatible/pkg/parsers/operatingsystem/operatingsystem_linux.go (about)

     1  // Package operatingsystem provides helper function to get the operating system
     2  // name for different platforms.
     3  package operatingsystem // import "github.com/docker/docker/pkg/parsers/operatingsystem"
     4  
     5  import (
     6  	"bufio"
     7  	"bytes"
     8  	"fmt"
     9  	"io/ioutil"
    10  	"os"
    11  	"strings"
    12  )
    13  
    14  var (
    15  	// file to use to detect if the daemon is running in a container
    16  	proc1Cgroup = "/proc/1/cgroup"
    17  
    18  	// file to check to determine Operating System
    19  	etcOsRelease = "/etc/os-release"
    20  
    21  	// used by stateless systems like Clear Linux
    22  	altOsRelease = "/usr/lib/os-release"
    23  )
    24  
    25  // GetOperatingSystem gets the name of the current operating system.
    26  func GetOperatingSystem() (string, error) {
    27  	if prettyName, err := getValueFromOsRelease("PRETTY_NAME"); err != nil {
    28  		return "", err
    29  	} else if prettyName != "" {
    30  		return prettyName, nil
    31  	}
    32  
    33  	// If not set, defaults to PRETTY_NAME="Linux"
    34  	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
    35  	return "Linux", nil
    36  }
    37  
    38  // GetOperatingSystemVersion gets the version of the current operating system, as a string.
    39  func GetOperatingSystemVersion() (string, error) {
    40  	return getValueFromOsRelease("VERSION_ID")
    41  }
    42  
    43  // parses the os-release file and returns the value associated with `key`
    44  func getValueFromOsRelease(key string) (string, error) {
    45  	osReleaseFile, err := os.Open(etcOsRelease)
    46  	if err != nil {
    47  		if !os.IsNotExist(err) {
    48  			return "", fmt.Errorf("Error opening %s: %v", etcOsRelease, err)
    49  		}
    50  		osReleaseFile, err = os.Open(altOsRelease)
    51  		if err != nil {
    52  			return "", fmt.Errorf("Error opening %s: %v", altOsRelease, err)
    53  		}
    54  	}
    55  	defer osReleaseFile.Close()
    56  
    57  	var value string
    58  	keyWithTrailingEqual := key + "="
    59  	scanner := bufio.NewScanner(osReleaseFile)
    60  	for scanner.Scan() {
    61  		line := scanner.Text()
    62  		if strings.HasPrefix(line, keyWithTrailingEqual) {
    63  			data := strings.SplitN(line, "=", 2)
    64  			value = strings.Trim(data[1], `"' `) // remove leading/trailing quotes and whitespace
    65  		}
    66  	}
    67  
    68  	return value, nil
    69  }
    70  
    71  // IsContainerized returns true if we are running inside a container.
    72  func IsContainerized() (bool, error) {
    73  	b, err := ioutil.ReadFile(proc1Cgroup)
    74  	if err != nil {
    75  		return false, err
    76  	}
    77  	for _, line := range bytes.Split(b, []byte{'\n'}) {
    78  		if len(line) > 0 && !bytes.HasSuffix(line, []byte(":/")) && !bytes.HasSuffix(line, []byte(":/init.scope")) {
    79  			return true, nil
    80  		}
    81  	}
    82  	return false, nil
    83  }