Upgrade dependencies to latest moby/moby.

Commands run:
```
$ gvt delete github.com/docker/docker/pkg/archive
$ gvt fetch -revision 239d61f04bf1c00273c1c89b531fe37993e08a9f github.com/moby/moby/pkg/archive
$ make clean ; make  # build failure
$ gvt delete github.com/docker/docker/pkg/fileutils
$ gvt fetch -revision 239d61f04bf1c00273c1c89b531fe37993e08a9f github.com/moby/moby/pkg/fileutils
$ make clean ; make  # build failure
$ gvt delete github.com/docker/docker/pkg/stdcopy
$ gvt fetch -revision 239d61f04bf1c00273c1c89b531fe37993e08a9f github.com/moby/moby/pkg/stdcopy
```
N.B.: following this commit, build fails with:
```
vendor/github.com/weaveworks/common/backoff/backoff.go:6:2: cannot find package "github.com/Sirupsen/logrus" in any of:
	/go/src/github.com/weaveworks/scope/vendor/github.com/Sirupsen/logrus (vendor tree)
	/usr/local/go/src/github.com/Sirupsen/logrus (from $GOROOT)
	/go/src/github.com/Sirupsen/logrus (from $GOPATH)
vendor/github.com/docker/docker/pkg/archive/archive.go:19:2: cannot find package "github.com/docker/docker/pkg/fileutils" in any of:
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/vendor/github.com/docker/docker/pkg/fileutils (vendor tree)
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/pkg/fileutils
	/usr/local/go/src/github.com/docker/docker/pkg/fileutils (from $GOROOT)
	/go/src/github.com/docker/docker/pkg/fileutils (from $GOPATH)
vendor/github.com/fsouza/go-dockerclient/client.go:35:2: cannot find package "github.com/docker/docker/pkg/stdcopy" in any of:
	/go/src/github.com/weaveworks/scope/vendor/github.com/docker/docker/pkg/stdcopy (vendor tree)
	/usr/local/go/src/github.com/docker/docker/pkg/stdcopy (from $GOROOT)
	/go/src/github.com/docker/docker/pkg/stdcopy (from $GOPATH)
```
Resolution in subsequent commit.

vendor/github.com/docker/docker/pkg/archive/LICENSE

@@ -176,7 +176,7 @@
 
    END OF TERMS AND CONDITIONS
 
-   Copyright 2013-2016 Docker, Inc.
+   Copyright 2013-2017 Docker, Inc.
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

vendor/github.com/docker/docker/pkg/archive/archive_linux.go

@@ -5,9 +5,9 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"syscall"
 
 	"github.com/docker/docker/pkg/system"
+	"golang.org/x/sys/unix"
 )
 
 func getWhiteoutConverter(format WhiteoutFormat) tarWhiteoutConverter {
@@ -19,25 +19,31 @@ func getWhiteoutConverter(format WhiteoutFormat) tarWhiteoutConverter {
 
 type overlayWhiteoutConverter struct{}
 
-func (overlayWhiteoutConverter) ConvertWrite(hdr *tar.Header, path string, fi os.FileInfo) error {
+func (overlayWhiteoutConverter) ConvertWrite(hdr *tar.Header, path string, fi os.FileInfo) (wo *tar.Header, err error) {
 	// convert whiteouts to AUFS format
 	if fi.Mode()&os.ModeCharDevice != 0 && hdr.Devmajor == 0 && hdr.Devminor == 0 {
 		// we just rename the file and make it normal
-		hdr.Name = WhiteoutPrefix + hdr.Name
+		dir, filename := filepath.Split(hdr.Name)
+		hdr.Name = filepath.Join(dir, WhiteoutPrefix+filename)
 		hdr.Mode = 0600
 		hdr.Typeflag = tar.TypeReg
+		hdr.Size = 0
 	}
 
 	if fi.Mode()&os.ModeDir != 0 {
 		// convert opaque dirs to AUFS format by writing an empty file with the prefix
 		opaque, err := system.Lgetxattr(path, "trusted.overlay.opaque")
 		if err != nil {
-			return err
+			return nil, err
 		}
-		if opaque != nil && len(opaque) == 1 && opaque[0] == 'y' {
+		if len(opaque) == 1 && opaque[0] == 'y' {
+			if hdr.Xattrs != nil {
+				delete(hdr.Xattrs, "trusted.overlay.opaque")
+			}
+
 			// create a header for the whiteout file
 			// it should inherit some properties from the parent, but be a regular file
-			*hdr = tar.Header{
+			wo = &tar.Header{
 				Typeflag:   tar.TypeReg,
 				Mode:       hdr.Mode & int64(os.ModePerm),
 				Name:       filepath.Join(hdr.Name, WhiteoutOpaqueDir),
@@ -52,7 +58,7 @@ func (overlayWhiteoutConverter) ConvertWrite(hdr *tar.Header, path string, fi os
 		}
 	}
 
-	return nil
+	return
 }
 
 func (overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (bool, error) {
@@ -61,12 +67,9 @@ func (overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (bool,
 
 	// if a directory is marked as opaque by the AUFS special file, we need to translate that to overlay
 	if base == WhiteoutOpaqueDir {
-		if err := syscall.Setxattr(dir, "trusted.overlay.opaque", []byte{'y'}, 0); err != nil {
-			return false, err
-		}
-
+		err := unix.Setxattr(dir, "trusted.overlay.opaque", []byte{'y'}, 0)
 		// don't write the file itself
-		return false, nil
+		return false, err
 	}
 
 	// if a file was deleted and we are using overlay, we need to create a character device
@@ -74,7 +77,7 @@ func (overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (bool,
 		originalBase := base[len(WhiteoutPrefix):]
 		originalPath := filepath.Join(dir, originalBase)
 
-		if err := syscall.Mknod(originalPath, syscall.S_IFCHR, 0); err != nil {
+		if err := unix.Mknod(originalPath, unix.S_IFCHR, 0); err != nil {
 			return false, err
 		}
 		if err := os.Chown(originalPath, hdr.Uid, hdr.Gid); err != nil {

vendor/github.com/docker/docker/pkg/archive/archive_unix.go

@@ -9,7 +9,10 @@ import (
 	"path/filepath"
 	"syscall"
 
+	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/system"
+	rsystem "github.com/opencontainers/runc/libcontainer/system"
+	"golang.org/x/sys/unix"
 )
 
 // fixVolumePathPrefix does platform specific processing to ensure that if
@@ -40,60 +43,59 @@ func chmodTarEntry(perm os.FileMode) os.FileMode {
 	return perm // noop for unix as golang APIs provide perm bits correctly
 }
 
-func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (inode uint64, err error) {
+func setHeaderForSpecialDevice(hdr *tar.Header, name string, stat interface{}) (err error) {
 	s, ok := stat.(*syscall.Stat_t)
 
-	if !ok {
-		err = errors.New("cannot convert stat value to syscall.Stat_t")
-		return
+	if ok {
+		// Currently go does not fill in the major/minors
+		if s.Mode&unix.S_IFBLK != 0 ||
+			s.Mode&unix.S_IFCHR != 0 {
+			hdr.Devmajor = int64(unix.Major(uint64(s.Rdev))) // nolint: unconvert
+			hdr.Devminor = int64(unix.Minor(uint64(s.Rdev))) // nolint: unconvert
+		}
 	}
 
-	inode = uint64(s.Ino)
+	return
+}
 
-	// Currently go does not fill in the major/minors
-	if s.Mode&syscall.S_IFBLK != 0 ||
-		s.Mode&syscall.S_IFCHR != 0 {
-		hdr.Devmajor = int64(major(uint64(s.Rdev)))
-		hdr.Devminor = int64(minor(uint64(s.Rdev)))
+func getInodeFromStat(stat interface{}) (inode uint64, err error) {
+	s, ok := stat.(*syscall.Stat_t)
+
+	if ok {
+		inode = s.Ino
 	}
 
 	return
 }
 
-func getFileUIDGID(stat interface{}) (int, int, error) {
+func getFileUIDGID(stat interface{}) (idtools.IDPair, error) {
 	s, ok := stat.(*syscall.Stat_t)
 
 	if !ok {
-		return -1, -1, errors.New("cannot convert stat value to syscall.Stat_t")
+		return idtools.IDPair{}, errors.New("cannot convert stat value to syscall.Stat_t")
 	}
-	return int(s.Uid), int(s.Gid), nil
-}
-
-func major(device uint64) uint64 {
-	return (device >> 8) & 0xfff
-}
-
-func minor(device uint64) uint64 {
-	return (device & 0xff) | ((device >> 12) & 0xfff00)
+	return idtools.IDPair{UID: int(s.Uid), GID: int(s.Gid)}, nil
 }
 
 // handleTarTypeBlockCharFifo is an OS-specific helper function used by
 // createTarFile to handle the following types of header: Block; Char; Fifo
 func handleTarTypeBlockCharFifo(hdr *tar.Header, path string) error {
+	if rsystem.RunningInUserNS() {
+		// cannot create a device if running in user namespace
+		return nil
+	}
+
 	mode := uint32(hdr.Mode & 07777)
 	switch hdr.Typeflag {
 	case tar.TypeBlock:
-		mode |= syscall.S_IFBLK
+		mode |= unix.S_IFBLK
 	case tar.TypeChar:
-		mode |= syscall.S_IFCHR
+		mode |= unix.S_IFCHR
 	case tar.TypeFifo:
-		mode |= syscall.S_IFIFO
+		mode |= unix.S_IFIFO
 	}
 
-	if err := system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor))); err != nil {
-		return err
-	}
-	return nil
+	return system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor)))
 }
 
 func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {

vendor/github.com/docker/docker/pkg/archive/archive_windows.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/longpath"
 )
 
@@ -42,15 +43,23 @@ func CanonicalTarNameForPath(p string) (string, error) {
 // chmodTarEntry is used to adjust the file permissions used in tar header based
 // on the platform the archival is done.
 func chmodTarEntry(perm os.FileMode) os.FileMode {
-	perm &= 0755
+	//perm &= 0755 // this 0-ed out tar flags (like link, regular file, directory marker etc.)
+	permPart := perm & os.ModePerm
+	noPermPart := perm &^ os.ModePerm
 	// Add the x bit: make everything +x from windows
-	perm |= 0111
+	permPart |= 0111
+	permPart &= 0755
 
-	return perm
+	return noPermPart | permPart
 }
 
-func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (inode uint64, err error) {
-	// do nothing. no notion of Rdev, Inode, Nlink in stat on Windows
+func setHeaderForSpecialDevice(hdr *tar.Header, name string, stat interface{}) (err error) {
+	// do nothing. no notion of Rdev, Nlink in stat on Windows
+	return
+}
+
+func getInodeFromStat(stat interface{}) (inode uint64, err error) {
+	// do nothing. no notion of Inode in stat on Windows
 	return
 }
 
@@ -64,7 +73,7 @@ func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
 	return nil
 }
 
-func getFileUIDGID(stat interface{}) (int, int, error) {
+func getFileUIDGID(stat interface{}) (idtools.IDPair, error) {
 	// no notion of file ownership mapping yet on Windows
-	return 0, 0, nil
+	return idtools.IDPair{0, 0}, nil
 }

vendor/github.com/docker/docker/pkg/archive/changes.go

@@ -13,10 +13,10 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/pools"
 	"github.com/docker/docker/pkg/system"
+	"github.com/sirupsen/logrus"
 )
 
 // ChangeType represents the change type.
@@ -267,7 +267,7 @@ func (info *FileInfo) addChanges(oldInfo *FileInfo, changes *[]Change) {
 	}
 
 	for name, newChild := range info.children {
-		oldChild, _ := oldChildren[name]
+		oldChild := oldChildren[name]
 		if oldChild != nil {
 			// change?
 			oldStat := oldChild.stat
@@ -279,7 +279,7 @@ func (info *FileInfo) addChanges(oldInfo *FileInfo, changes *[]Change) {
 			// breaks down is if some code intentionally hides a change by setting
 			// back mtime
 			if statDifferent(oldStat, newStat) ||
-				bytes.Compare(oldChild.capability, newChild.capability) != 0 {
+				!bytes.Equal(oldChild.capability, newChild.capability) {
 				change := Change{
 					Path: newChild.path(),
 					Kind: ChangeModify,
@@ -391,16 +391,11 @@ func ChangesSize(newDir string, changes []Change) int64 {
 }
 
 // ExportChanges produces an Archive from the provided changes, relative to dir.
-func ExportChanges(dir string, changes []Change, uidMaps, gidMaps []idtools.IDMap) (Archive, error) {
+func ExportChanges(dir string, changes []Change, uidMaps, gidMaps []idtools.IDMap) (io.ReadCloser, error) {
 	reader, writer := io.Pipe()
 	go func() {
-		ta := &tarAppender{
-			TarWriter: tar.NewWriter(writer),
-			Buffer:    pools.BufioWriter32KPool.Get(nil),
-			SeenFiles: make(map[uint64]string),
-			UIDMaps:   uidMaps,
-			GIDMaps:   gidMaps,
-		}
+		ta := newTarAppender(idtools.NewIDMappingsFromMaps(uidMaps, gidMaps), writer, nil)
+
 		// this buffer is needed for the duration of this piped stream
 		defer pools.BufioWriter32KPool.Put(ta.Buffer)
 

vendor/github.com/docker/docker/pkg/archive/changes_linux.go

@@ -10,6 +10,7 @@ import (
 	"unsafe"
 
 	"github.com/docker/docker/pkg/system"
+	"golang.org/x/sys/unix"
 )
 
 // walker is used to implement collectFileInfoForChanges on linux. Where this
@@ -65,7 +66,7 @@ func walkchunk(path string, fi os.FileInfo, dir string, root *FileInfo) error {
 	}
 	parent := root.LookUp(filepath.Dir(path))
 	if parent == nil {
-		return fmt.Errorf("collectFileInfoForChanges: Unexpectedly no parent for %s", path)
+		return fmt.Errorf("walkchunk: Unexpectedly no parent for %s", path)
 	}
 	info := &FileInfo{
 		name:     filepath.Base(path),
@@ -233,7 +234,7 @@ func readdirnames(dirname string) (names []nameIno, err error) {
 		// Refill the buffer if necessary
 		if bufp >= nbuf {
 			bufp = 0
-			nbuf, err = syscall.ReadDirent(int(f.Fd()), buf) // getdents on linux
+			nbuf, err = unix.ReadDirent(int(f.Fd()), buf) // getdents on linux
 			if nbuf < 0 {
 				nbuf = 0
 			}
@@ -255,12 +256,12 @@ func readdirnames(dirname string) (names []nameIno, err error) {
 	return sl, nil
 }
 
-// parseDirent is a minor modification of syscall.ParseDirent (linux version)
+// parseDirent is a minor modification of unix.ParseDirent (linux version)
 // which returns {name,inode} pairs instead of just names.
 func parseDirent(buf []byte, names []nameIno) (consumed int, newnames []nameIno) {
 	origlen := len(buf)
 	for len(buf) > 0 {
-		dirent := (*syscall.Dirent)(unsafe.Pointer(&buf[0]))
+		dirent := (*unix.Dirent)(unsafe.Pointer(&buf[0]))
 		buf = buf[dirent.Reclen:]
 		if dirent.Ino == 0 { // File absent in directory.
 			continue
@@ -293,7 +294,7 @@ func OverlayChanges(layers []string, rw string) ([]Change, error) {
 func overlayDeletedFile(root, path string, fi os.FileInfo) (string, error) {
 	if fi.Mode()&os.ModeCharDevice != 0 {
 		s := fi.Sys().(*syscall.Stat_t)
-		if major(uint64(s.Rdev)) == 0 && minor(uint64(s.Rdev)) == 0 {
+		if unix.Major(uint64(s.Rdev)) == 0 && unix.Minor(uint64(s.Rdev)) == 0 { // nolint: unconvert
 			return path, nil
 		}
 	}
@@ -302,7 +303,7 @@ func overlayDeletedFile(root, path string, fi os.FileInfo) (string, error) {
 		if err != nil {
 			return "", err
 		}
-		if opaque != nil && len(opaque) == 1 && opaque[0] == 'y' {
+		if len(opaque) == 1 && opaque[0] == 'y' {
 			return path, nil
 		}
 	}

vendor/github.com/docker/docker/pkg/archive/changes_unix.go

@@ -7,6 +7,7 @@ import (
 	"syscall"
 
 	"github.com/docker/docker/pkg/system"
+	"golang.org/x/sys/unix"
 )
 
 func statDifferent(oldStat *system.StatT, newStat *system.StatT) bool {
@@ -16,7 +17,7 @@ func statDifferent(oldStat *system.StatT, newStat *system.StatT) bool {
 		oldStat.GID() != newStat.GID() ||
 		oldStat.Rdev() != newStat.Rdev() ||
 		// Don't look at size for dirs, its not a good measure of change
-		(oldStat.Mode()&syscall.S_IFDIR != syscall.S_IFDIR &&
+		(oldStat.Mode()&unix.S_IFDIR != unix.S_IFDIR &&
 			(!sameFsTimeSpec(oldStat.Mtim(), newStat.Mtim()) || (oldStat.Size() != newStat.Size()))) {
 		return true
 	}
@@ -24,11 +25,11 @@ func statDifferent(oldStat *system.StatT, newStat *system.StatT) bool {
 }
 
 func (info *FileInfo) isDir() bool {
-	return info.parent == nil || info.stat.Mode()&syscall.S_IFDIR != 0
+	return info.parent == nil || info.stat.Mode()&unix.S_IFDIR != 0
 }
 
 func getIno(fi os.FileInfo) uint64 {
-	return uint64(fi.Sys().(*syscall.Stat_t).Ino)
+	return fi.Sys().(*syscall.Stat_t).Ino
 }
 
 func hasHardlinks(fi os.FileInfo) bool {

vendor/github.com/docker/docker/pkg/archive/changes_windows.go

@@ -9,16 +9,16 @@ import (
 func statDifferent(oldStat *system.StatT, newStat *system.StatT) bool {
 
 	// Don't look at size for dirs, its not a good measure of change
-	if oldStat.ModTime() != newStat.ModTime() ||
+	if oldStat.Mtim() != newStat.Mtim() ||
 		oldStat.Mode() != newStat.Mode() ||
-		oldStat.Size() != newStat.Size() && !oldStat.IsDir() {
+		oldStat.Size() != newStat.Size() && !oldStat.Mode().IsDir() {
 		return true
 	}
 	return false
 }
 
 func (info *FileInfo) isDir() bool {
-	return info.parent == nil || info.stat.IsDir()
+	return info.parent == nil || info.stat.Mode().IsDir()
 }
 
 func getIno(fi os.FileInfo) (inode uint64) {

vendor/github.com/docker/docker/pkg/archive/copy.go

@@ -9,8 +9,8 @@ import (
 	"path/filepath"
 	"strings"
 
-	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/pkg/system"
+	"github.com/sirupsen/logrus"
 )
 
 // Errors used or returned by this file.
@@ -27,23 +27,23 @@ var (
 // path (from before being processed by utility functions from the path or
 // filepath stdlib packages) ends with a trailing `/.` or `/`. If the cleaned
 // path already ends in a `.` path segment, then another is not added. If the
-// clean path already ends in a path separator, then another is not added.
-func PreserveTrailingDotOrSeparator(cleanedPath, originalPath string) string {
+// clean path already ends in the separator, then another is not added.
+func PreserveTrailingDotOrSeparator(cleanedPath string, originalPath string, sep byte) string {
 	// Ensure paths are in platform semantics
-	cleanedPath = normalizePath(cleanedPath)
-	originalPath = normalizePath(originalPath)
+	cleanedPath = strings.Replace(cleanedPath, "/", string(sep), -1)
+	originalPath = strings.Replace(originalPath, "/", string(sep), -1)
 
 	if !specifiesCurrentDir(cleanedPath) && specifiesCurrentDir(originalPath) {
-		if !hasTrailingPathSeparator(cleanedPath) {
+		if !hasTrailingPathSeparator(cleanedPath, sep) {
 			// Add a separator if it doesn't already end with one (a cleaned
 			// path would only end in a separator if it is the root).
-			cleanedPath += string(filepath.Separator)
+			cleanedPath += string(sep)
 		}
 		cleanedPath += "."
 	}
 
-	if !hasTrailingPathSeparator(cleanedPath) && hasTrailingPathSeparator(originalPath) {
-		cleanedPath += string(filepath.Separator)
+	if !hasTrailingPathSeparator(cleanedPath, sep) && hasTrailingPathSeparator(originalPath, sep) {
+		cleanedPath += string(sep)
 	}
 
 	return cleanedPath
@@ -52,14 +52,14 @@ func PreserveTrailingDotOrSeparator(cleanedPath, originalPath string) string {
 // assertsDirectory returns whether the given path is
 // asserted to be a directory, i.e., the path ends with
 // a trailing '/' or `/.`, assuming a path separator of `/`.
-func assertsDirectory(path string) bool {
-	return hasTrailingPathSeparator(path) || specifiesCurrentDir(path)
+func assertsDirectory(path string, sep byte) bool {
+	return hasTrailingPathSeparator(path, sep) || specifiesCurrentDir(path)
 }
 
 // hasTrailingPathSeparator returns whether the given
 // path ends with the system's path separator character.
-func hasTrailingPathSeparator(path string) bool {
-	return len(path) > 0 && os.IsPathSeparator(path[len(path)-1])
+func hasTrailingPathSeparator(path string, sep byte) bool {
+	return len(path) > 0 && path[len(path)-1] == sep
 }
 
 // specifiesCurrentDir returns whether the given path specifies
@@ -72,10 +72,10 @@ func specifiesCurrentDir(path string) bool {
 // basename by first cleaning the path but preserves a trailing "." if the
 // original path specified the current directory.
 func SplitPathDirEntry(path string) (dir, base string) {
-	cleanedPath := filepath.Clean(normalizePath(path))
+	cleanedPath := filepath.Clean(filepath.FromSlash(path))
 
 	if specifiesCurrentDir(path) {
-		cleanedPath += string(filepath.Separator) + "."
+		cleanedPath += string(os.PathSeparator) + "."
 	}
 
 	return filepath.Dir(cleanedPath), filepath.Base(cleanedPath)
@@ -88,13 +88,13 @@ func SplitPathDirEntry(path string) (dir, base string) {
 // This function acts as a convenient wrapper around TarWithOptions, which
 // requires a directory as the source path. TarResource accepts either a
 // directory or a file path and correctly sets the Tar options.
-func TarResource(sourceInfo CopyInfo) (content Archive, err error) {
+func TarResource(sourceInfo CopyInfo) (content io.ReadCloser, err error) {
 	return TarResourceRebase(sourceInfo.Path, sourceInfo.RebaseName)
 }
 
 // TarResourceRebase is like TarResource but renames the first path element of
 // items in the resulting tar archive to match the given rebaseName if not "".
-func TarResourceRebase(sourcePath, rebaseName string) (content Archive, err error) {
+func TarResourceRebase(sourcePath, rebaseName string) (content io.ReadCloser, err error) {
 	sourcePath = normalizePath(sourcePath)
 	if _, err = os.Lstat(sourcePath); err != nil {
 		// Catches the case where the source does not exist or is not a
@@ -103,22 +103,27 @@ func TarResourceRebase(sourcePath, rebaseName string) (content Archive, err erro
 		return
 	}
 
-	// Separate the source path between it's directory and
+	// Separate the source path between its directory and
 	// the entry in that directory which we are archiving.
 	sourceDir, sourceBase := SplitPathDirEntry(sourcePath)
-
-	filter := []string{sourceBase}
+	opts := TarResourceRebaseOpts(sourceBase, rebaseName)
 
 	logrus.Debugf("copying %q from %q", sourceBase, sourceDir)
+	return TarWithOptions(sourceDir, opts)
+}
 
-	return TarWithOptions(sourceDir, &TarOptions{
+// TarResourceRebaseOpts does not preform the Tar, but instead just creates the rebase
+// parameters to be sent to TarWithOptions (the TarOptions struct)
+func TarResourceRebaseOpts(sourceBase string, rebaseName string) *TarOptions {
+	filter := []string{sourceBase}
+	return &TarOptions{
 		Compression:      Uncompressed,
 		IncludeFiles:     filter,
 		IncludeSourceDir: true,
 		RebaseNames: map[string]string{
 			sourceBase: rebaseName,
 		},
-	})
+	}
 }
 
 // CopyInfo holds basic info about the source
@@ -218,7 +223,7 @@ func CopyInfoDestinationPath(path string) (info CopyInfo, err error) {
 		// Ensure destination parent dir exists.
 		dstParent, _ := SplitPathDirEntry(path)
 
-		parentDirStat, err := os.Lstat(dstParent)
+		parentDirStat, err := os.Stat(dstParent)
 		if err != nil {
 			return CopyInfo{}, err
 		}
@@ -241,7 +246,7 @@ func CopyInfoDestinationPath(path string) (info CopyInfo, err error) {
 // contain the archived resource described by srcInfo, to the destination
 // described by dstInfo. Returns the possibly modified content archive along
 // with the path to the destination directory which it should be extracted to.
-func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir string, content Archive, err error) {
+func PrepareArchiveCopy(srcContent io.Reader, srcInfo, dstInfo CopyInfo) (dstDir string, content io.ReadCloser, err error) {
 	// Ensure in platform semantics
 	srcInfo.Path = normalizePath(srcInfo.Path)
 	dstInfo.Path = normalizePath(dstInfo.Path)
@@ -281,7 +286,7 @@ func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir st
 			srcBase = srcInfo.RebaseName
 		}
 		return dstDir, RebaseArchiveEntries(srcContent, srcBase, dstBase), nil
-	case assertsDirectory(dstInfo.Path):
+	case assertsDirectory(dstInfo.Path, os.PathSeparator):
 		// The destination does not exist and is asserted to be created as a
 		// directory, but the source content is not a directory. This is an
 		// error condition since you cannot create a directory from a file
@@ -304,7 +309,7 @@ func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir st
 
 // RebaseArchiveEntries rewrites the given srcContent archive replacing
 // an occurrence of oldBase with newBase at the beginning of entry names.
-func RebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
+func RebaseArchiveEntries(srcContent io.Reader, oldBase, newBase string) io.ReadCloser {
 	if oldBase == string(os.PathSeparator) {
 		// If oldBase specifies the root directory, use an empty string as
 		// oldBase instead so that newBase doesn't replace the path separator
@@ -332,6 +337,9 @@ func RebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
 			}
 
 			hdr.Name = strings.Replace(hdr.Name, oldBase, newBase, 1)
+			if hdr.Typeflag == tar.TypeLink {
+				hdr.Linkname = strings.Replace(hdr.Linkname, oldBase, newBase, 1)
+			}
 
 			if err = rebasedTar.WriteHeader(hdr); err != nil {
 				w.CloseWithError(err)
@@ -348,6 +356,9 @@ func RebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
 	return rebased
 }
 
+// TODO @gupta-ak. These might have to be changed in the future to be
+// continuity driver aware as well to support LCOW.
+
 // CopyResource performs an archive copy from the given source path to the
 // given destination path. The source path MUST exist and the destination
 // path's parent directory must exist.
@@ -362,8 +373,8 @@ func CopyResource(srcPath, dstPath string, followLink bool) error {
 	dstPath = normalizePath(dstPath)
 
 	// Clean the source and destination paths.
-	srcPath = PreserveTrailingDotOrSeparator(filepath.Clean(srcPath), srcPath)
-	dstPath = PreserveTrailingDotOrSeparator(filepath.Clean(dstPath), dstPath)
+	srcPath = PreserveTrailingDotOrSeparator(filepath.Clean(srcPath), srcPath, os.PathSeparator)
+	dstPath = PreserveTrailingDotOrSeparator(filepath.Clean(dstPath), dstPath, os.PathSeparator)
 
 	if srcInfo, err = CopyInfoSourcePath(srcPath, followLink); err != nil {
 		return err
@@ -380,7 +391,7 @@ func CopyResource(srcPath, dstPath string, followLink bool) error {
 
 // CopyTo handles extracting the given content whose
 // entries should be sourced from srcInfo to dstPath.
-func CopyTo(content Reader, srcInfo CopyInfo, dstPath string) error {
+func CopyTo(content io.Reader, srcInfo CopyInfo, dstPath string) error {
 	// The destination path need not exist, but CopyInfoDestinationPath will
 	// ensure that at least the parent directory exists.
 	dstInfo, err := CopyInfoDestinationPath(normalizePath(dstPath))
@@ -426,7 +437,8 @@ func ResolveHostSourcePath(path string, followLink bool) (resolvedPath, rebaseNa
 		// resolvedDirPath will have been cleaned (no trailing path separators) so
 		// we can manually join it with the base path element.
 		resolvedPath = resolvedDirPath + string(filepath.Separator) + basePath
-		if hasTrailingPathSeparator(path) && filepath.Base(path) != filepath.Base(resolvedPath) {
+		if hasTrailingPathSeparator(path, os.PathSeparator) &&
+			filepath.Base(path) != filepath.Base(resolvedPath) {
 			rebaseName = filepath.Base(path)
 		}
 	}
@@ -439,11 +451,13 @@ func GetRebaseName(path, resolvedPath string) (string, string) {
 	// linkTarget will have been cleaned (no trailing path separators and dot) so
 	// we can manually join it with them
 	var rebaseName string
-	if specifiesCurrentDir(path) && !specifiesCurrentDir(resolvedPath) {
+	if specifiesCurrentDir(path) &&
+		!specifiesCurrentDir(resolvedPath) {
 		resolvedPath += string(filepath.Separator) + "."
 	}
 
-	if hasTrailingPathSeparator(path) && !hasTrailingPathSeparator(resolvedPath) {
+	if hasTrailingPathSeparator(path, os.PathSeparator) &&
+		!hasTrailingPathSeparator(resolvedPath, os.PathSeparator) {
 		resolvedPath += string(filepath.Separator)
 	}
 

vendor/github.com/docker/docker/pkg/archive/diff.go

@@ -10,16 +10,16 @@ import (
 	"runtime"
 	"strings"
 
-	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/pools"
 	"github.com/docker/docker/pkg/system"
+	"github.com/sirupsen/logrus"
 )
 
 // UnpackLayer unpack `layer` to a `dest`. The stream `layer` can be
 // compressed or uncompressed.
 // Returns the size in bytes of the contents of the layer.
-func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, err error) {
+func UnpackLayer(dest string, layer io.Reader, options *TarOptions) (size int64, err error) {
 	tr := tar.NewReader(layer)
 	trBuf := pools.BufioReader32KPool.Get(tr)
 	defer pools.BufioReader32KPool.Put(trBuf)
@@ -33,17 +33,11 @@ func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, er
 	if options.ExcludePatterns == nil {
 		options.ExcludePatterns = []string{}
 	}
-	remappedRootUID, remappedRootGID, err := idtools.GetRootUIDGID(options.UIDMaps, options.GIDMaps)
-	if err != nil {
-		return 0, err
-	}
+	idMappings := idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps)
 
 	aufsTempdir := ""
 	aufsHardlinks := make(map[string]*tar.Header)
 
-	if options == nil {
-		options = &TarOptions{}
-	}
 	// Iterate through the files in the archive.
 	for {
 		hdr, err := tr.Next()
@@ -90,7 +84,7 @@ func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, er
 			parentPath := filepath.Join(dest, parent)
 
 			if _, err := os.Lstat(parentPath); err != nil && os.IsNotExist(err) {
-				err = system.MkdirAll(parentPath, 0600)
+				err = system.MkdirAll(parentPath, 0600, "")
 				if err != nil {
 					return 0, err
 				}
@@ -111,7 +105,7 @@ func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, er
 					}
 					defer os.RemoveAll(aufsTempdir)
 				}
-				if err := createTarFile(filepath.Join(aufsTempdir, basename), dest, hdr, tr, true, nil); err != nil {
+				if err := createTarFile(filepath.Join(aufsTempdir, basename), dest, hdr, tr, true, nil, options.InUserNS); err != nil {
 					return 0, err
 				}
 			}
@@ -198,28 +192,11 @@ func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, er
 				srcData = tmpFile
 			}
 
-			// if the options contain a uid & gid maps, convert header uid/gid
-			// entries using the maps such that lchown sets the proper mapped
-			// uid/gid after writing the file. We only perform this mapping if
-			// the file isn't already owned by the remapped root UID or GID, as
-			// that specific uid/gid has no mapping from container -> host, and
-			// those files already have the proper ownership for inside the
-			// container.
-			if srcHdr.Uid != remappedRootUID {
-				xUID, err := idtools.ToHost(srcHdr.Uid, options.UIDMaps)
-				if err != nil {
-					return 0, err
-				}
-				srcHdr.Uid = xUID
-			}
-			if srcHdr.Gid != remappedRootGID {
-				xGID, err := idtools.ToHost(srcHdr.Gid, options.GIDMaps)
-				if err != nil {
-					return 0, err
-				}
-				srcHdr.Gid = xGID
+			if err := remapIDs(idMappings, srcHdr); err != nil {
+				return 0, err
 			}
-			if err := createTarFile(path, dest, srcHdr, srcData, true, nil); err != nil {
+
+			if err := createTarFile(path, dest, srcHdr, srcData, true, nil, options.InUserNS); err != nil {
 				return 0, err
 			}
 
@@ -246,7 +223,7 @@ func UnpackLayer(dest string, layer Reader, options *TarOptions) (size int64, er
 // and applies it to the directory `dest`. The stream `layer` can be
 // compressed or uncompressed.
 // Returns the size in bytes of the contents of the layer.
-func ApplyLayer(dest string, layer Reader) (int64, error) {
+func ApplyLayer(dest string, layer io.Reader) (int64, error) {
 	return applyLayerHandler(dest, layer, &TarOptions{}, true)
 }
 
@@ -254,12 +231,12 @@ func ApplyLayer(dest string, layer Reader) (int64, error) {
 // `layer`, and applies it to the directory `dest`. The stream `layer`
 // can only be uncompressed.
 // Returns the size in bytes of the contents of the layer.
-func ApplyUncompressedLayer(dest string, layer Reader, options *TarOptions) (int64, error) {
+func ApplyUncompressedLayer(dest string, layer io.Reader, options *TarOptions) (int64, error) {
 	return applyLayerHandler(dest, layer, options, false)
 }
 
 // do the bulk load of ApplyLayer, but allow for not calling DecompressStream
-func applyLayerHandler(dest string, layer Reader, options *TarOptions, decompress bool) (int64, error) {
+func applyLayerHandler(dest string, layer io.Reader, options *TarOptions, decompress bool) (int64, error) {
 	dest = filepath.Clean(dest)
 
 	// We need to be able to set any perms

vendor/github.com/docker/docker/pkg/archive/example_changes.go

@@ -13,8 +13,8 @@ import (
 	"os"
 	"path"
 
-	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/pkg/archive"
+	"github.com/sirupsen/logrus"
 )
 
 var (

vendor/github.com/docker/docker/pkg/archive/wrap.go

@@ -3,7 +3,7 @@ package archive
 import (
 	"archive/tar"
 	"bytes"
-	"io/ioutil"
+	"io"
 )
 
 // Generate generates a new archive from the content provided
@@ -22,7 +22,7 @@ import (
 //
 // FIXME: stream content instead of buffering
 // FIXME: specify permissions and other archive metadata
-func Generate(input ...string) (Archive, error) {
+func Generate(input ...string) (io.Reader, error) {
 	files := parseStringPairs(input...)
 	buf := new(bytes.Buffer)
 	tw := tar.NewWriter(buf)
@@ -42,7 +42,7 @@ func Generate(input ...string) (Archive, error) {
 	if err := tw.Close(); err != nil {
 		return nil, err
 	}
-	return ioutil.NopCloser(buf), nil
+	return buf, nil
 }
 
 func parseStringPairs(input ...string) (output [][2]string) {

vendor/github.com/docker/docker/pkg/fileutils/LICENSE → vendor/github.com/docker/docker/vendor/archive/tar/LICENSE

@@ -176,7 +176,7 @@
 
    END OF TERMS AND CONDITIONS
 
-   Copyright 2013-2016 Docker, Inc.
+   Copyright 2013-2017 Docker, Inc.
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

vendor/github.com/docker/docker/vendor/archive/tar/common.go

+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package tar implements access to tar archives.
+// It aims to cover most of the variations, including those produced
+// by GNU and BSD tars.
+//
+// References:
+//   http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
+//   http://www.gnu.org/software/tar/manual/html_node/Standard.html
+//   http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
+package tar
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"time"
+)
+
+// BUG: Use of the Uid and Gid fields in Header could overflow on 32-bit
+// architectures. If a large value is encountered when decoding, the result
+// stored in Header will be the truncated version.
+
+// Header type flags.
+const (
+	TypeReg           = '0'    // regular file
+	TypeRegA          = '\x00' // regular file
+	TypeLink          = '1'    // hard link
+	TypeSymlink       = '2'    // symbolic link
+	TypeChar          = '3'    // character device node
+	TypeBlock         = '4'    // block device node
+	TypeDir           = '5'    // directory
+	TypeFifo          = '6'    // fifo node
+	TypeCont          = '7'    // reserved
+	TypeXHeader       = 'x'    // extended header
+	TypeXGlobalHeader = 'g'    // global extended header
+	TypeGNULongName   = 'L'    // Next file has a long name
+	TypeGNULongLink   = 'K'    // Next file symlinks to a file w/ a long name
+	TypeGNUSparse     = 'S'    // sparse file
+)
+
+// A Header represents a single header in a tar archive.
+// Some fields may not be populated.
+type Header struct {
+	Name       string    // name of header file entry
+	Mode       int64     // permission and mode bits
+	Uid        int       // user id of owner
+	Gid        int       // group id of owner
+	Size       int64     // length in bytes
+	ModTime    time.Time // modified time
+	Typeflag   byte      // type of header entry
+	Linkname   string    // target name of link
+	Uname      string    // user name of owner
+	Gname      string    // group name of owner
+	Devmajor   int64     // major number of character or block device
+	Devminor   int64     // minor number of character or block device
+	AccessTime time.Time // access time
+	ChangeTime time.Time // status change time
+	Xattrs     map[string]string
+}
+
+// FileInfo returns an os.FileInfo for the Header.
+func (h *Header) FileInfo() os.FileInfo {
+	return headerFileInfo{h}
+}
+
+// headerFileInfo implements os.FileInfo.
+type headerFileInfo struct {
+	h *Header
+}
+
+func (fi headerFileInfo) Size() int64        { return fi.h.Size }
+func (fi headerFileInfo) IsDir() bool        { return fi.Mode().IsDir() }
+func (fi headerFileInfo) ModTime() time.Time { return fi.h.ModTime }
+func (fi headerFileInfo) Sys() interface{}   { return fi.h }
+
+// Name returns the base name of the file.
+func (fi headerFileInfo) Name() string {
+	if fi.IsDir() {
+		return path.Base(path.Clean(fi.h.Name))
+	}
+	return path.Base(fi.h.Name)
+}
+
+// Mode returns the permission and mode bits for the headerFileInfo.
+func (fi headerFileInfo) Mode() (mode os.FileMode) {
+	// Set file permission bits.
+	mode = os.FileMode(fi.h.Mode).Perm()
+
+	// Set setuid, setgid and sticky bits.
+	if fi.h.Mode&c_ISUID != 0 {
+		// setuid
+		mode |= os.ModeSetuid
+	}
+	if fi.h.Mode&c_ISGID != 0 {
+		// setgid
+		mode |= os.ModeSetgid
+	}
+	if fi.h.Mode&c_ISVTX != 0 {
+		// sticky
+		mode |= os.ModeSticky
+	}
+
+	// Set file mode bits.
+	// clear perm, setuid, setgid and sticky bits.
+	m := os.FileMode(fi.h.Mode) &^ 07777
+	if m == c_ISDIR {
+		// directory
+		mode |= os.ModeDir
+	}
+	if m == c_ISFIFO {
+		// named pipe (FIFO)
+		mode |= os.ModeNamedPipe
+	}
+	if m == c_ISLNK {
+		// symbolic link
+		mode |= os.ModeSymlink
+	}
+	if m == c_ISBLK {
+		// device file
+		mode |= os.ModeDevice
+	}
+	if m == c_ISCHR {
+		// Unix character device
+		mode |= os.ModeDevice
+		mode |= os.ModeCharDevice
+	}
+	if m == c_ISSOCK {
+		// Unix domain socket
+		mode |= os.ModeSocket
+	}
+
+	switch fi.h.Typeflag {
+	case TypeSymlink:
+		// symbolic link
+		mode |= os.ModeSymlink
+	case TypeChar:
+		// character device node
+		mode |= os.ModeDevice
+		mode |= os.ModeCharDevice
+	case TypeBlock:
+		// block device node
+		mode |= os.ModeDevice
+	case TypeDir:
+		// directory
+		mode |= os.ModeDir
+	case TypeFifo:
+		// fifo node
+		mode |= os.ModeNamedPipe
+	}
+
+	return mode
+}
+
+// sysStat, if non-nil, populates h from system-dependent fields of fi.
+var sysStat func(fi os.FileInfo, h *Header) error
+
+// Mode constants from the tar spec.
+const (
+	c_ISUID  = 04000   // Set uid
+	c_ISGID  = 02000   // Set gid
+	c_ISVTX  = 01000   // Save text (sticky bit)
+	c_ISDIR  = 040000  // Directory
+	c_ISFIFO = 010000  // FIFO
+	c_ISREG  = 0100000 // Regular file
+	c_ISLNK  = 0120000 // Symbolic link
+	c_ISBLK  = 060000  // Block special file
+	c_ISCHR  = 020000  // Character special file
+	c_ISSOCK = 0140000 // Socket
+)
+
+// Keywords for the PAX Extended Header
+const (
+	paxAtime    = "atime"
+	paxCharset  = "charset"
+	paxComment  = "comment"
+	paxCtime    = "ctime" // please note that ctime is not a valid pax header.
+	paxGid      = "gid"
+	paxGname    = "gname"
+	paxLinkpath = "linkpath"
+	paxMtime    = "mtime"
+	paxPath     = "path"
+	paxSize     = "size"
+	paxUid      = "uid"
+	paxUname    = "uname"
+	paxXattr    = "SCHILY.xattr."
+	paxNone     = ""
+)
+
+// FileInfoHeader creates a partially-populated Header from fi.
+// If fi describes a symlink, FileInfoHeader records link as the link target.
+// If fi describes a directory, a slash is appended to the name.
+// Because os.FileInfo's Name method returns only the base name of
+// the file it describes, it may be necessary to modify the Name field
+// of the returned header to provide the full path name of the file.
+func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
+	if fi == nil {
+		return nil, errors.New("tar: FileInfo is nil")
+	}
+	fm := fi.Mode()
+	h := &Header{
+		Name:    fi.Name(),
+		ModTime: fi.ModTime(),
+		Mode:    int64(fm.Perm()), // or'd with c_IS* constants later
+	}
+	switch {
+	case fm.IsRegular():
+		h.Mode |= c_ISREG
+		h.Typeflag = TypeReg
+		h.Size = fi.Size()
+	case fi.IsDir():
+		h.Typeflag = TypeDir
+		h.Mode |= c_ISDIR
+		h.Name += "/"
+	case fm&os.ModeSymlink != 0:
+		h.Typeflag = TypeSymlink
+		h.Mode |= c_ISLNK
+		h.Linkname = link
+	case fm&os.ModeDevice != 0:
+		if fm&os.ModeCharDevice != 0 {
+			h.Mode |= c_ISCHR
+			h.Typeflag = TypeChar
+		} else {
+			h.Mode |= c_ISBLK
+			h.Typeflag = TypeBlock
+		}
+	case fm&os.ModeNamedPipe != 0:
+		h.Typeflag = TypeFifo
+		h.Mode |= c_ISFIFO
+	case fm&os.ModeSocket != 0:
+		h.Mode |= c_ISSOCK
+	default:
+		return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm)
+	}
+	if fm&os.ModeSetuid != 0 {
+		h.Mode |= c_ISUID
+	}
+	if fm&os.ModeSetgid != 0 {
+		h.Mode |= c_ISGID
+	}
+	if fm&os.ModeSticky != 0 {
+		h.Mode |= c_ISVTX
+	}
+	// If possible, populate additional fields from OS-specific
+	// FileInfo fields.
+	if sys, ok := fi.Sys().(*Header); ok {
+		// This FileInfo came from a Header (not the OS). Use the
+		// original Header to populate all remaining fields.
+		h.Uid = sys.Uid
+		h.Gid = sys.Gid
+		h.Uname = sys.Uname
+		h.Gname = sys.Gname
+		h.AccessTime = sys.AccessTime
+		h.ChangeTime = sys.ChangeTime
+		if sys.Xattrs != nil {
+			h.Xattrs = make(map[string]string)
+			for k, v := range sys.Xattrs {
+				h.Xattrs[k] = v
+			}
+		}
+		if sys.Typeflag == TypeLink {
+			// hard link
+			h.Typeflag = TypeLink
+			h.Size = 0
+			h.Linkname = sys.Linkname
+		}
+	}
+	if sysStat != nil {
+		return h, sysStat(fi, h)
+	}
+	return h, nil
+}
+
+// isHeaderOnlyType checks if the given type flag is of the type that has no
+// data section even if a size is specified.
+func isHeaderOnlyType(flag byte) bool {
+	switch flag {
+	case TypeLink, TypeSymlink, TypeChar, TypeBlock, TypeDir, TypeFifo:
+		return true
+	default:
+		return false
+	}
+}

vendor/github.com/docker/docker/vendor/archive/tar/format.go

+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tar
+
+// Constants to identify various tar formats.
+const (
+	// The format is unknown.
+	formatUnknown = (1 << iota) / 2 // Sequence of 0, 1, 2, 4, 8, etc...
+
+	// The format of the original Unix V7 tar tool prior to standardization.
+	formatV7
+
+	// The old and new GNU formats, which are incompatible with USTAR.
+	// This does cover the old GNU sparse extension.
+	// This does not cover the GNU sparse extensions using PAX headers,
+	// versions 0.0, 0.1, and 1.0; these fall under the PAX format.
+	formatGNU
+
+	// Schily's tar format, which is incompatible with USTAR.
+	// This does not cover STAR extensions to the PAX format; these fall under
+	// the PAX format.
+	formatSTAR
+
+	// USTAR is the former standardization of tar defined in POSIX.1-1988.
+	// This is incompatible with the GNU and STAR formats.
+	formatUSTAR
+
+	// PAX is the latest standardization of tar defined in POSIX.1-2001.
+	// This is an extension of USTAR and is "backwards compatible" with it.
+	//
+	// Some newer formats add their own extensions to PAX, such as GNU sparse
+	// files and SCHILY extended attributes. Since they are backwards compatible
+	// with PAX, they will be labelled as "PAX".
+	formatPAX
+)
+
+// Magics used to identify various formats.
+const (
+	magicGNU, versionGNU     = "ustar ", " \x00"
+	magicUSTAR, versionUSTAR = "ustar\x00", "00"
+	trailerSTAR              = "tar\x00"
+)
+
+// Size constants from various tar specifications.
+const (
+	blockSize  = 512 // Size of each block in a tar stream
+	nameSize   = 100 // Max length of the name field in USTAR format
+	prefixSize = 155 // Max length of the prefix field in USTAR format
+)
+
+var zeroBlock block
+
+type block [blockSize]byte
+
+// Convert block to any number of formats.
+func (b *block) V7() *headerV7       { return (*headerV7)(b) }
+func (b *block) GNU() *headerGNU     { return (*headerGNU)(b) }
+func (b *block) STAR() *headerSTAR   { return (*headerSTAR)(b) }
+func (b *block) USTAR() *headerUSTAR { return (*headerUSTAR)(b) }
+func (b *block) Sparse() sparseArray { return (sparseArray)(b[:]) }
+
+// GetFormat checks that the block is a valid tar header based on the checksum.
+// It then attempts to guess the specific format based on magic values.
+// If the checksum fails, then formatUnknown is returned.
+func (b *block) GetFormat() (format int) {
+	// Verify checksum.
+	var p parser
+	value := p.parseOctal(b.V7().Chksum())
+	chksum1, chksum2 := b.ComputeChecksum()
+	if p.err != nil || (value != chksum1 && value != chksum2) {
+		return formatUnknown
+	}
+
+	// Guess the magic values.
+	magic := string(b.USTAR().Magic())
+	version := string(b.USTAR().Version())
+	trailer := string(b.STAR().Trailer())
+	switch {
+	case magic == magicUSTAR && trailer == trailerSTAR:
+		return formatSTAR
+	case magic == magicUSTAR:
+		return formatUSTAR
+	case magic == magicGNU && version == versionGNU:
+		return formatGNU
+	default:
+		return formatV7
+	}
+}
+
+// SetFormat writes the magic values necessary for specified format
+// and then updates the checksum accordingly.
+func (b *block) SetFormat(format int) {
+	// Set the magic values.
+	switch format {
+	case formatV7:
+		// Do nothing.
+	case formatGNU:
+		copy(b.GNU().Magic(), magicGNU)
+		copy(b.GNU().Version(), versionGNU)
+	case formatSTAR:
+		copy(b.STAR().Magic(), magicUSTAR)
+		copy(b.STAR().Version(), versionUSTAR)
+		copy(b.STAR().Trailer(), trailerSTAR)
+	case formatUSTAR, formatPAX:
+		copy(b.USTAR().Magic(), magicUSTAR)
+		copy(b.USTAR().Version(), versionUSTAR)
+	default:
+		panic("invalid format")
+	}
+
+	// Update checksum.
+	// This field is special in that it is terminated by a NULL then space.
+	var f formatter
+	field := b.V7().Chksum()
+	chksum, _ := b.ComputeChecksum() // Possible values are 256..128776
+	f.formatOctal(field[:7], chksum) // Never fails since 128776 < 262143
+	field[7] = ' '
+}
+
+// ComputeChecksum computes the checksum for the header block.
+// POSIX specifies a sum of the unsigned byte values, but the Sun tar used
+// signed byte values.
+// We compute and return both.
+func (b *block) ComputeChecksum() (unsigned, signed int64) {
+	for i, c := range b {
+		if 148 <= i && i < 156 {
+			c = ' ' // Treat the checksum field itself as all spaces.
+		}
+		unsigned += int64(uint8(c))
+		signed += int64(int8(c))
+	}
+	return unsigned, signed
+}
+
+type headerV7 [blockSize]byte
+
+func (h *headerV7) Name() []byte     { return h[000:][:100] }
+func (h *headerV7) Mode() []byte     { return h[100:][:8] }
+func (h *headerV7) UID() []byte      { return h[108:][:8] }
+func (h *headerV7) GID() []byte      { return h[116:][:8] }
+func (h *headerV7) Size() []byte     { return h[124:][:12] }
+func (h *headerV7) ModTime() []byte  { return h[136:][:12] }
+func (h *headerV7) Chksum() []byte   { return h[148:][:8] }
+func (h *headerV7) TypeFlag() []byte { return h[156:][:1] }
+func (h *headerV7) LinkName() []byte { return h[157:][:100] }
+
+type headerGNU [blockSize]byte
+
+func (h *headerGNU) V7() *headerV7       { return (*headerV7)(h) }
+func (h *headerGNU) Magic() []byte       { return h[257:][:6] }
+func (h *headerGNU) Version() []byte     { return h[263:][:2] }
+func (h *headerGNU) UserName() []byte    { return h[265:][:32] }
+func (h *headerGNU) GroupName() []byte   { return h[297:][:32] }
+func (h *headerGNU) DevMajor() []byte    { return h[329:][:8] }
+func (h *headerGNU) DevMinor() []byte    { return h[337:][:8] }
+func (h *headerGNU) AccessTime() []byte  { return h[345:][:12] }
+func (h *headerGNU) ChangeTime() []byte  { return h[357:][:12] }
+func (h *headerGNU) Sparse() sparseArray { return (sparseArray)(h[386:][:24*4+1]) }
+func (h *headerGNU) RealSize() []byte    { return h[483:][:12] }
+
+type headerSTAR [blockSize]byte
+
+func (h *headerSTAR) V7() *headerV7      { return (*headerV7)(h) }
+func (h *headerSTAR) Magic() []byte      { return h[257:][:6] }
+func (h *headerSTAR) Version() []byte    { return h[263:][:2] }
+func (h *headerSTAR) UserName() []byte   { return h[265:][:32] }
+func (h *headerSTAR) GroupName() []byte  { return h[297:][:32] }
+func (h *headerSTAR) DevMajor() []byte   { return h[329:][:8] }
+func (h *headerSTAR) DevMinor() []byte   { return h[337:][:8] }
+func (h *headerSTAR) Prefix() []byte     { return h[345:][:131] }
+func (h *headerSTAR) AccessTime() []byte { return h[476:][:12] }
+func (h *headerSTAR) ChangeTime() []byte { return h[488:][:12] }
+func (h *headerSTAR) Trailer() []byte    { return h[508:][:4] }
+
+type headerUSTAR [blockSize]byte
+
+func (h *headerUSTAR) V7() *headerV7     { return (*headerV7)(h) }
+func (h *headerUSTAR) Magic() []byte     { return h[257:][:6] }
+func (h *headerUSTAR) Version() []byte   { return h[263:][:2] }
+func (h *headerUSTAR) UserName() []byte  { return h[265:][:32] }
+func (h *headerUSTAR) GroupName() []byte { return h[297:][:32] }
+func (h *headerUSTAR) DevMajor() []byte  { return h[329:][:8] }
+func (h *headerUSTAR) DevMinor() []byte  { return h[337:][:8] }
+func (h *headerUSTAR) Prefix() []byte    { return h[345:][:155] }
+
+type sparseArray []byte
+
+func (s sparseArray) Entry(i int) sparseNode { return (sparseNode)(s[i*24:]) }
+func (s sparseArray) IsExtended() []byte     { return s[24*s.MaxEntries():][:1] }
+func (s sparseArray) MaxEntries() int        { return len(s) / 24 }
+
+type sparseNode []byte
+
+func (s sparseNode) Offset() []byte   { return s[00:][:12] }
+func (s sparseNode) NumBytes() []byte { return s[12:][:12] }

vendor/github.com/docker/docker/vendor/archive/tar/stat_atim.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux dragonfly openbsd solaris
+
+package tar
+
+import (
+	"syscall"
+	"time"
+)
+
+func statAtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Atim.Unix())
+}
+
+func statCtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Ctim.Unix())
+}

vendor/github.com/docker/docker/vendor/archive/tar/stat_atimespec.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd netbsd
+
+package tar
+
+import (
+	"syscall"
+	"time"
+)
+
+func statAtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Atimespec.Unix())
+}
+
+func statCtime(st *syscall.Stat_t) time.Time {
+	return time.Unix(st.Ctimespec.Unix())
+}

vendor/github.com/docker/docker/vendor/archive/tar/stat_unix.go

+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux darwin dragonfly freebsd openbsd netbsd solaris
+
+package tar
+
+import (
+	"os"
+	"syscall"
+)
+
+func init() {
+	sysStat = statUnix
+}
+
+func statUnix(fi os.FileInfo, h *Header) error {
+	sys, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return nil
+	}
+	h.Uid = int(sys.Uid)
+	h.Gid = int(sys.Gid)
+	// TODO(bradfitz): populate username & group.  os/user
+	// doesn't cache LookupId lookups, and lacks group
+	// lookup functions.
+	h.AccessTime = statAtime(sys)
+	h.ChangeTime = statCtime(sys)
+	// TODO(bradfitz): major/minor device numbers?
+	return nil
+}