github.com/kaisenlinux/docker.io@v0.0.0-20230510090727-ea55db55fac7/engine/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  	"os"
    10  	"strings"
    11  )
    12  
    13  var (
    14  	// file to use to detect if the daemon is running in a container
    15  	proc1Cgroup = "/proc/1/cgroup"
    16  
    17  	// file to check to determine Operating System
    18  	etcOsRelease = "/etc/os-release"
    19  
    20  	// used by stateless systems like Clear Linux
    21  	altOsRelease = "/usr/lib/os-release"
    22  )
    23  
    24  // GetOperatingSystem gets the name of the current operating system.
    25  func GetOperatingSystem() (string, error) {
    26  	if prettyName, err := getValueFromOsRelease("PRETTY_NAME"); err != nil {
    27  		return "", err
    28  	} else if prettyName != "" {
    29  		return prettyName, nil
    30  	}
    31  
    32  	// If not set, defaults to PRETTY_NAME="Linux"
    33  	// c.f. http://www.freedesktop.org/software/systemd/man/os-release.html
    34  	return "Linux", nil
    35  }
    36  
    37  // GetOperatingSystemVersion gets the version of the current operating system, as a string.
    38  func GetOperatingSystemVersion() (string, error) {
    39  	return getValueFromOsRelease("VERSION_ID")
    40  }
    41  
    42  // parses the os-release file and returns the value associated with `key`
    43  func getValueFromOsRelease(key string) (string, error) {
    44  	osReleaseFile, err := os.Open(etcOsRelease)
    45  	if err != nil {
    46  		if !os.IsNotExist(err) {
    47  			return "", fmt.Errorf("Error opening %s: %v", etcOsRelease, err)
    48  		}
    49  		osReleaseFile, err = os.Open(altOsRelease)
    50  		if err != nil {
    51  			return "", fmt.Errorf("Error opening %s: %v", altOsRelease, err)
    52  		}
    53  	}
    54  	defer osReleaseFile.Close()
    55  
    56  	var value string
    57  	keyWithTrailingEqual := key + "="
    58  	scanner := bufio.NewScanner(osReleaseFile)
    59  	for scanner.Scan() {
    60  		line := scanner.Text()
    61  		if strings.HasPrefix(line, keyWithTrailingEqual) {
    62  			data := strings.SplitN(line, "=", 2)
    63  			value = strings.Trim(data[1], `"' `) // remove leading/trailing quotes and whitespace
    64  		}
    65  	}
    66  
    67  	return value, nil
    68  }
    69  
    70  // IsContainerized returns true if we are running inside a container.
    71  func IsContainerized() (bool, error) {
    72  	b, err := os.ReadFile(proc1Cgroup)
    73  	if err != nil {
    74  		return false, err
    75  	}
    76  	for _, line := range bytes.Split(b, []byte{'\n'}) {
    77  		if len(line) > 0 && !bytes.HasSuffix(line, []byte(":/")) && !bytes.HasSuffix(line, []byte(":/init.scope")) {
    78  			return true, nil
    79  		}
    80  	}
    81  	return false, nil
    82  }