github.com/Prakhar-Agarwal-byte/moby@v0.0.0-20231027092010-a14e3e8ab87e/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/Prakhar-Agarwal-byte/moby/pkg/parsers/operatingsystem"
     4  
     5  import (
     6  	"bufio"
     7  	"bytes"
     8  	"os"
     9  	"strings"
    10  )
    11  
    12  var (
    13  	// file to use to detect if the daemon is running in a container
    14  	proc1Cgroup = "/proc/1/cgroup"
    15  
    16  	// file to check to determine Operating System
    17  	etcOsRelease = "/etc/os-release"
    18  
    19  	// used by stateless systems like Clear Linux
    20  	altOsRelease = "/usr/lib/os-release"
    21  )
    22  
    23  // GetOperatingSystem gets the name of the current operating system.
    24  func GetOperatingSystem() (string, error) {
    25  	if prettyName, err := getValueFromOsRelease("PRETTY_NAME"); err != nil {
    26  		return "", err
    27  	} else if prettyName != "" {
    28  		return prettyName, nil
    29  	}
    30  
    31  	// If not set, defaults to PRETTY_NAME="Linux"
    32  	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
    33  	return "Linux", nil
    34  }
    35  
    36  // GetOperatingSystemVersion gets the version of the current operating system, as a string.
    37  func GetOperatingSystemVersion() (string, error) {
    38  	return getValueFromOsRelease("VERSION_ID")
    39  }
    40  
    41  // parses the os-release file and returns the value associated with `key`
    42  func getValueFromOsRelease(key string) (string, error) {
    43  	osReleaseFile, err := os.Open(etcOsRelease)
    44  	if err != nil {
    45  		if !os.IsNotExist(err) {
    46  			return "", err
    47  		}
    48  		osReleaseFile, err = os.Open(altOsRelease)
    49  		if err != nil {
    50  			return "", err
    51  		}
    52  	}
    53  	defer osReleaseFile.Close()
    54  
    55  	var value string
    56  	scanner := bufio.NewScanner(osReleaseFile)
    57  	for scanner.Scan() {
    58  		line := scanner.Text()
    59  		if strings.HasPrefix(line, key+"=") {
    60  			value = strings.TrimPrefix(line, key+"=")
    61  			value = strings.Trim(value, `"' `) // remove leading/trailing quotes and whitespace
    62  		}
    63  	}
    64  
    65  	return value, nil
    66  }
    67  
    68  // IsContainerized returns true if we are running inside a container.
    69  func IsContainerized() (bool, error) {
    70  	b, err := os.ReadFile(proc1Cgroup)
    71  	if err != nil {
    72  		return false, err
    73  	}
    74  	for _, line := range bytes.Split(b, []byte{'\n'}) {
    75  		if len(line) > 0 && !bytes.HasSuffix(line, []byte(":/")) && !bytes.HasSuffix(line, []byte(":/init.scope")) {
    76  			return true, nil
    77  		}
    78  	}
    79  	return false, nil
    80  }