mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
256 lines
7.8 KiB
Go
256 lines
7.8 KiB
Go
package archive
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import (
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"archive/tar"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"runtime"
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"strings"
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"github.com/Sirupsen/logrus"
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"github.com/docker/docker/pkg/idtools"
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"github.com/docker/docker/pkg/pools"
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"github.com/docker/docker/pkg/system"
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)
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// UnpackLayer unpack `layer` to a `dest`. The stream `layer` can be
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// compressed or uncompressed.
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// Returns the size in bytes of the contents of the layer.
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func UnpackLayer(dest string, layer io.Reader, options *TarOptions) (size int64, err error) {
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tr := tar.NewReader(layer)
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trBuf := pools.BufioReader32KPool.Get(tr)
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defer pools.BufioReader32KPool.Put(trBuf)
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var dirs []*tar.Header
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unpackedPaths := make(map[string]struct{})
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if options == nil {
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options = &TarOptions{}
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}
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if options.ExcludePatterns == nil {
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options.ExcludePatterns = []string{}
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}
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idMappings := idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps)
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aufsTempdir := ""
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aufsHardlinks := make(map[string]*tar.Header)
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// Iterate through the files in the archive.
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for {
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hdr, err := tr.Next()
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if err == io.EOF {
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// end of tar archive
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break
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}
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if err != nil {
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return 0, err
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}
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size += hdr.Size
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// Normalize name, for safety and for a simple is-root check
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hdr.Name = filepath.Clean(hdr.Name)
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// Windows does not support filenames with colons in them. Ignore
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// these files. This is not a problem though (although it might
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// appear that it is). Let's suppose a client is running docker pull.
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// The daemon it points to is Windows. Would it make sense for the
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// client to be doing a docker pull Ubuntu for example (which has files
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// with colons in the name under /usr/share/man/man3)? No, absolutely
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// not as it would really only make sense that they were pulling a
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// Windows image. However, for development, it is necessary to be able
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// to pull Linux images which are in the repository.
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//
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// TODO Windows. Once the registry is aware of what images are Windows-
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// specific or Linux-specific, this warning should be changed to an error
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// to cater for the situation where someone does manage to upload a Linux
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// image but have it tagged as Windows inadvertently.
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if runtime.GOOS == "windows" {
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if strings.Contains(hdr.Name, ":") {
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logrus.Warnf("Windows: Ignoring %s (is this a Linux image?)", hdr.Name)
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continue
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}
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}
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// Note as these operations are platform specific, so must the slash be.
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if !strings.HasSuffix(hdr.Name, string(os.PathSeparator)) {
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// Not the root directory, ensure that the parent directory exists.
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// This happened in some tests where an image had a tarfile without any
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// parent directories.
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parent := filepath.Dir(hdr.Name)
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parentPath := filepath.Join(dest, parent)
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if _, err := os.Lstat(parentPath); err != nil && os.IsNotExist(err) {
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err = system.MkdirAll(parentPath, 0600)
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if err != nil {
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return 0, err
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}
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}
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}
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// Skip AUFS metadata dirs
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if strings.HasPrefix(hdr.Name, WhiteoutMetaPrefix) {
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// Regular files inside /.wh..wh.plnk can be used as hardlink targets
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// We don't want this directory, but we need the files in them so that
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// such hardlinks can be resolved.
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if strings.HasPrefix(hdr.Name, WhiteoutLinkDir) && hdr.Typeflag == tar.TypeReg {
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basename := filepath.Base(hdr.Name)
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aufsHardlinks[basename] = hdr
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if aufsTempdir == "" {
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if aufsTempdir, err = ioutil.TempDir("", "dockerplnk"); err != nil {
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return 0, err
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}
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defer os.RemoveAll(aufsTempdir)
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}
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if err := createTarFile(filepath.Join(aufsTempdir, basename), dest, hdr, tr, true, nil, options.InUserNS); err != nil {
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return 0, err
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}
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}
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if hdr.Name != WhiteoutOpaqueDir {
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continue
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}
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}
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path := filepath.Join(dest, hdr.Name)
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rel, err := filepath.Rel(dest, path)
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if err != nil {
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return 0, err
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}
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// Note as these operations are platform specific, so must the slash be.
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if strings.HasPrefix(rel, ".."+string(os.PathSeparator)) {
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return 0, breakoutError(fmt.Errorf("%q is outside of %q", hdr.Name, dest))
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}
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base := filepath.Base(path)
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if strings.HasPrefix(base, WhiteoutPrefix) {
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dir := filepath.Dir(path)
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if base == WhiteoutOpaqueDir {
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_, err := os.Lstat(dir)
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if err != nil {
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return 0, err
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}
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err = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
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if err != nil {
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if os.IsNotExist(err) {
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err = nil // parent was deleted
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}
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return err
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}
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if path == dir {
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return nil
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}
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if _, exists := unpackedPaths[path]; !exists {
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err := os.RemoveAll(path)
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return err
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}
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return nil
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})
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if err != nil {
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return 0, err
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}
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} else {
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originalBase := base[len(WhiteoutPrefix):]
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originalPath := filepath.Join(dir, originalBase)
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if err := os.RemoveAll(originalPath); err != nil {
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return 0, err
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}
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}
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} else {
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// If path exits we almost always just want to remove and replace it.
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// The only exception is when it is a directory *and* the file from
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// the layer is also a directory. Then we want to merge them (i.e.
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// just apply the metadata from the layer).
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if fi, err := os.Lstat(path); err == nil {
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if !(fi.IsDir() && hdr.Typeflag == tar.TypeDir) {
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if err := os.RemoveAll(path); err != nil {
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return 0, err
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}
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}
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}
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trBuf.Reset(tr)
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srcData := io.Reader(trBuf)
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srcHdr := hdr
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// Hard links into /.wh..wh.plnk don't work, as we don't extract that directory, so
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// we manually retarget these into the temporary files we extracted them into
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if hdr.Typeflag == tar.TypeLink && strings.HasPrefix(filepath.Clean(hdr.Linkname), WhiteoutLinkDir) {
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linkBasename := filepath.Base(hdr.Linkname)
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srcHdr = aufsHardlinks[linkBasename]
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if srcHdr == nil {
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return 0, fmt.Errorf("Invalid aufs hardlink")
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}
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tmpFile, err := os.Open(filepath.Join(aufsTempdir, linkBasename))
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if err != nil {
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return 0, err
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}
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defer tmpFile.Close()
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srcData = tmpFile
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}
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if err := remapIDs(idMappings, srcHdr); err != nil {
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return 0, err
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}
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if err := createTarFile(path, dest, srcHdr, srcData, true, nil, options.InUserNS); err != nil {
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return 0, err
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}
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// Directory mtimes must be handled at the end to avoid further
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// file creation in them to modify the directory mtime
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if hdr.Typeflag == tar.TypeDir {
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dirs = append(dirs, hdr)
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}
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unpackedPaths[path] = struct{}{}
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}
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}
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for _, hdr := range dirs {
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path := filepath.Join(dest, hdr.Name)
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if err := system.Chtimes(path, hdr.AccessTime, hdr.ModTime); err != nil {
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return 0, err
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}
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}
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return size, nil
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}
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// ApplyLayer parses a diff in the standard layer format from `layer`,
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// and applies it to the directory `dest`. The stream `layer` can be
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// compressed or uncompressed.
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// Returns the size in bytes of the contents of the layer.
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func ApplyLayer(dest string, layer io.Reader) (int64, error) {
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return applyLayerHandler(dest, layer, &TarOptions{}, true)
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}
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// ApplyUncompressedLayer parses a diff in the standard layer format from
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// `layer`, and applies it to the directory `dest`. The stream `layer`
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// can only be uncompressed.
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// Returns the size in bytes of the contents of the layer.
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func ApplyUncompressedLayer(dest string, layer io.Reader, options *TarOptions) (int64, error) {
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return applyLayerHandler(dest, layer, options, false)
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}
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// do the bulk load of ApplyLayer, but allow for not calling DecompressStream
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func applyLayerHandler(dest string, layer io.Reader, options *TarOptions, decompress bool) (int64, error) {
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dest = filepath.Clean(dest)
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// We need to be able to set any perms
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oldmask, err := system.Umask(0)
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if err != nil {
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return 0, err
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}
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defer system.Umask(oldmask) // ignore err, ErrNotSupportedPlatform
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if decompress {
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layer, err = DecompressStream(layer)
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if err != nil {
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return 0, err
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}
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}
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return UnpackLayer(dest, layer, options)
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}
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