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moby--moby/utils/utils.go

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package utils
import (
"bufio"
"crypto/sha1"
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"encoding/hex"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
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"runtime"
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"strings"
"github.com/docker/docker/autogen/dockerversion"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/fileutils"
"github.com/docker/docker/pkg/stringid"
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)
// SelfPath figures out the absolute path of our own binary (if it's still around).
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func SelfPath() string {
path, err := exec.LookPath(os.Args[0])
if err != nil {
if os.IsNotExist(err) {
return ""
}
if execErr, ok := err.(*exec.Error); ok && os.IsNotExist(execErr.Err) {
return ""
}
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panic(err)
}
path, err = filepath.Abs(path)
if err != nil {
if os.IsNotExist(err) {
return ""
}
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panic(err)
}
return path
}
func dockerInitSha1(target string) string {
f, err := os.Open(target)
if err != nil {
return ""
}
defer f.Close()
h := sha1.New()
_, err = io.Copy(h, f)
if err != nil {
return ""
}
return hex.EncodeToString(h.Sum(nil))
}
func isValidDockerInitPath(target string, selfPath string) bool { // target and selfPath should be absolute (InitPath and SelfPath already do this)
if target == "" {
return false
}
if dockerversion.IAMSTATIC == "true" {
if selfPath == "" {
return false
}
if target == selfPath {
return true
}
targetFileInfo, err := os.Lstat(target)
if err != nil {
return false
}
selfPathFileInfo, err := os.Lstat(selfPath)
if err != nil {
return false
}
return os.SameFile(targetFileInfo, selfPathFileInfo)
}
return dockerversion.INITSHA1 != "" && dockerInitSha1(target) == dockerversion.INITSHA1
}
// DockerInitPath figures out the path of our dockerinit (which may be SelfPath())
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func DockerInitPath(localCopy string) string {
selfPath := SelfPath()
if isValidDockerInitPath(selfPath, selfPath) {
// if we're valid, don't bother checking anything else
return selfPath
}
var possibleInits = []string{
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localCopy,
dockerversion.INITPATH,
filepath.Join(filepath.Dir(selfPath), "dockerinit"),
// FHS 3.0 Draft: "/usr/libexec includes internal binaries that are not intended to be executed directly by users or shell scripts. Applications may use a single subdirectory under /usr/libexec."
// https://www.linuxbase.org/betaspecs/fhs/fhs.html#usrlibexec
"/usr/libexec/docker/dockerinit",
"/usr/local/libexec/docker/dockerinit",
// FHS 2.3: "/usr/lib includes object files, libraries, and internal binaries that are not intended to be executed directly by users or shell scripts."
// https://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html#USRLIBLIBRARIESFORPROGRAMMINGANDPA
"/usr/lib/docker/dockerinit",
"/usr/local/lib/docker/dockerinit",
}
for _, dockerInit := range possibleInits {
if dockerInit == "" {
continue
}
path, err := exec.LookPath(dockerInit)
if err == nil {
path, err = filepath.Abs(path)
if err != nil {
// LookPath already validated that this file exists and is executable (following symlinks), so how could Abs fail?
panic(err)
}
if isValidDockerInitPath(path, selfPath) {
return path
}
}
}
return ""
}
var globalTestID string
// TestDirectory creates a new temporary directory and returns its path.
// The contents of directory at path `templateDir` is copied into the
// new directory.
func TestDirectory(templateDir string) (dir string, err error) {
if globalTestID == "" {
globalTestID = stringid.GenerateNonCryptoID()[:4]
}
prefix := fmt.Sprintf("docker-test%s-%s-", globalTestID, GetCallerName(2))
if prefix == "" {
prefix = "docker-test-"
}
dir, err = ioutil.TempDir("", prefix)
if err = os.Remove(dir); err != nil {
return
}
if templateDir != "" {
if err = archive.CopyWithTar(templateDir, dir); err != nil {
return
}
}
return
}
// GetCallerName introspects the call stack and returns the name of the
// function `depth` levels down in the stack.
func GetCallerName(depth int) string {
// Use the caller function name as a prefix.
// This helps trace temp directories back to their test.
pc, _, _, _ := runtime.Caller(depth + 1)
callerLongName := runtime.FuncForPC(pc).Name()
parts := strings.Split(callerLongName, ".")
callerShortName := parts[len(parts)-1]
return callerShortName
}
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// ReplaceOrAppendEnvValues returns the defaults with the overrides either
// replaced by env key or appended to the list
func ReplaceOrAppendEnvValues(defaults, overrides []string) []string {
cache := make(map[string]int, len(defaults))
for i, e := range defaults {
parts := strings.SplitN(e, "=", 2)
cache[parts[0]] = i
}
for _, value := range overrides {
// Values w/o = means they want this env to be removed/unset.
if !strings.Contains(value, "=") {
if i, exists := cache[value]; exists {
defaults[i] = "" // Used to indicate it should be removed
}
continue
}
// Just do a normal set/update
parts := strings.SplitN(value, "=", 2)
if i, exists := cache[parts[0]]; exists {
defaults[i] = value
} else {
defaults = append(defaults, value)
}
}
// Now remove all entries that we want to "unset"
for i := 0; i < len(defaults); i++ {
if defaults[i] == "" {
defaults = append(defaults[:i], defaults[i+1:]...)
i--
}
}
return defaults
}
// ValidateContextDirectory checks if all the contents of the directory
// can be read and returns an error if some files can't be read
// symlinks which point to non-existing files don't trigger an error
func ValidateContextDirectory(srcPath string, excludes []string) error {
return filepath.Walk(filepath.Join(srcPath, "."), func(filePath string, f os.FileInfo, err error) error {
// skip this directory/file if it's not in the path, it won't get added to the context
if relFilePath, err := filepath.Rel(srcPath, filePath); err != nil {
return err
} else if skip, err := fileutils.Matches(relFilePath, excludes); err != nil {
return err
} else if skip {
if f.IsDir() {
return filepath.SkipDir
}
return nil
}
if err != nil {
if os.IsPermission(err) {
return fmt.Errorf("can't stat '%s'", filePath)
}
if os.IsNotExist(err) {
return nil
}
return err
}
// skip checking if symlinks point to non-existing files, such symlinks can be useful
// also skip named pipes, because they hanging on open
if f.Mode()&(os.ModeSymlink|os.ModeNamedPipe) != 0 {
return nil
}
if !f.IsDir() {
currentFile, err := os.Open(filePath)
if err != nil && os.IsPermission(err) {
return fmt.Errorf("no permission to read from '%s'", filePath)
}
currentFile.Close()
}
return nil
})
}
// ReadDockerIgnore reads a .dockerignore file and returns the list of file patterns
// to ignore. Note this will trim whitespace from each line as well
// as use GO's "clean" func to get the shortest/cleanest path for each.
func ReadDockerIgnore(path string) ([]string, error) {
// Note that a missing .dockerignore file isn't treated as an error
reader, err := os.Open(path)
if err != nil {
if !os.IsNotExist(err) {
return nil, fmt.Errorf("Error reading '%s': %v", path, err)
}
return nil, nil
}
defer reader.Close()
scanner := bufio.NewScanner(reader)
var excludes []string
for scanner.Scan() {
pattern := strings.TrimSpace(scanner.Text())
if pattern == "" {
continue
}
pattern = filepath.Clean(pattern)
excludes = append(excludes, pattern)
}
if err = scanner.Err(); err != nil {
return nil, fmt.Errorf("Error reading '%s': %v", path, err)
}
return excludes, nil
}
// ImageReference combines `repo` and `ref` and returns a string representing
// the combination. If `ref` is a digest (meaning it's of the form
// <algorithm>:<digest>, the returned string is <repo>@<ref>. Otherwise,
// ref is assumed to be a tag, and the returned string is <repo>:<tag>.
func ImageReference(repo, ref string) string {
if DigestReference(ref) {
return repo + "@" + ref
}
return repo + ":" + ref
}
// DigestReference returns true if ref is a digest reference; i.e. if it
// is of the form <algorithm>:<digest>.
func DigestReference(ref string) bool {
return strings.Contains(ref, ":")
}