func writeLayerFromTar(r archive.Reader, w hcsshim.LayerWriter) (int64, error) {
t := tar.NewReader(r)
hdr, err := t.Next()
totalSize := int64(0)
buf := bufio.NewWriter(nil)
for err == nil {
base := path.Base(hdr.Name)
if strings.HasPrefix(base, archive.WhiteoutPrefix) {
name := path.Join(path.Dir(hdr.Name), base[len(archive.WhiteoutPrefix):])
err = w.Remove(filepath.FromSlash(name))
if err != nil {
return 0, err
}
hdr, err = t.Next()
} else if hdr.Typeflag == tar.TypeLink {
err = w.AddLink(filepath.FromSlash(hdr.Name), filepath.FromSlash(hdr.Linkname))
if err != nil {
return 0, err
}
hdr, err = t.Next()
} else {
var (
name string
size int64
fileInfo *winio.FileBasicInfo
)
name, size, fileInfo, err = backuptar.FileInfoFromHeader(hdr)
if err != nil {
return 0, err
}
err = w.Add(filepath.FromSlash(name), fileInfo)
if err != nil {
return 0, err
}
buf.Reset(w)
hdr, err = backuptar.WriteBackupStreamFromTarFile(buf, t, hdr)
ferr := buf.Flush()
if ferr != nil {
err = ferr
}
totalSize += size
}
}
if err != io.EOF {
return 0, err
}
return totalSize, nil
}
// writeBackupStreamFromTarAndSaveMutatedFiles reads data from a tar stream and
// writes it to a backup stream, and also saves any files that will be mutated
// by the import layer process to a backup location.
func writeBackupStreamFromTarAndSaveMutatedFiles(buf *bufio.Writer, w io.Writer, t *tar.Reader, hdr *tar.Header, root string) (nextHdr *tar.Header, err error) {
var bcdBackup *os.File
var bcdBackupWriter *winio.BackupFileWriter
if backupPath, ok := mutatedFiles[hdr.Name]; ok {
bcdBackup, err = os.Create(filepath.Join(root, backupPath))
if err != nil {
return nil, err
}
defer func() {
cerr := bcdBackup.Close()
if err == nil {
err = cerr
}
}()
bcdBackupWriter = winio.NewBackupFileWriter(bcdBackup, false)
defer func() {
cerr := bcdBackupWriter.Close()
if err == nil {
err = cerr
}
}()
buf.Reset(io.MultiWriter(w, bcdBackupWriter))
} else {
buf.Reset(w)
}
defer func() {
ferr := buf.Flush()
if err == nil {
err = ferr
}
}()
return backuptar.WriteBackupStreamFromTarFile(buf, t, hdr)
}
func writeLayerFromTar(r archive.Reader, w hcsshim.LayerWriter) (int64, error) {
t := tar.NewReader(r)
hdr, err := t.Next()
totalSize := int64(0)
buf := bufio.NewWriter(nil)
for err == nil {
base := path.Base(hdr.Name)
if strings.HasPrefix(base, archive.WhiteoutPrefix) {
name := path.Join(path.Dir(hdr.Name), base[len(archive.WhiteoutPrefix):])
err = w.Remove(filepath.FromSlash(name))
if err != nil {
return 0, err
}
hdr, err = t.Next()
} else if hdr.Typeflag == tar.TypeLink {
err = w.AddLink(filepath.FromSlash(hdr.Name), filepath.FromSlash(hdr.Linkname))
if err != nil {
return 0, err
}
hdr, err = t.Next()
} else {
var (
name string
size int64
fileInfo *winio.FileBasicInfo
)
name, size, fileInfo, err = backuptar.FileInfoFromHeader(hdr)
if err != nil {
return 0, err
}
err = w.Add(filepath.FromSlash(name), fileInfo)
if err != nil {
return 0, err
}
buf.Reset(w)
// Add the Hyper-V Virutal Machine group ACE to the security descriptor
// for TP5 so that Xenons can access all files. This is not necessary
// for post-TP5 builds.
if isTP5OrOlder() {
if sddl, ok := hdr.Winheaders["sd"]; ok {
var ace string
if hdr.Typeflag == tar.TypeDir {
ace = "(A;OICI;0x1200a9;;;S-1-5-83-0)"
} else {
ace = "(A;;0x1200a9;;;S-1-5-83-0)"
}
if hdr.Winheaders["sd"], ok = addAceToSddlDacl(sddl, ace); !ok {
logrus.Debugf("failed to add VM ACE to %s", sddl)
}
}
}
hdr, err = backuptar.WriteBackupStreamFromTarFile(buf, t, hdr)
ferr := buf.Flush()
if ferr != nil {
err = ferr
}
totalSize += size
}
}
if err != io.EOF {
return 0, err
}
return totalSize, nil
}