// WriteBackupStreamFromTarFile writes a Win32 backup stream from the current tar file. Since this function may process multiple
// tar file entries in order to collect all the alternate data streams for the file, it returns the next
// tar file that was not processed, or io.EOF is there are no more.
func WriteBackupStreamFromTarFile(w io.Writer, t *tar.Reader, hdr *tar.Header) (*tar.Header, error) {
bw := winio.NewBackupStreamWriter(w)
var sd []byte
var err error
// Maintaining old SDDL-based behavior for backward compatibility. All new tar headers written
// by this library will have raw binary for the security descriptor.
if sddl, ok := hdr.Winheaders[hdrSecurityDescriptor]; ok {
sd, err = winio.SddlToSecurityDescriptor(sddl)
if err != nil {
return nil, err
}
}
if sdraw, ok := hdr.Winheaders[hdrRawSecurityDescriptor]; ok {
sd, err = base64.StdEncoding.DecodeString(sdraw)
if err != nil {
return nil, err
}
}
if len(sd) != 0 {
bhdr := winio.BackupHeader{
Id: winio.BackupSecurity,
Size: int64(len(sd)),
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(sd)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeSymlink {
_, isMountPoint := hdr.Winheaders[hdrMountPoint]
rp := winio.ReparsePoint{
Target: filepath.FromSlash(hdr.Linkname),
IsMountPoint: isMountPoint,
}
reparse := winio.EncodeReparsePoint(&rp)
bhdr := winio.BackupHeader{
Id: winio.BackupReparseData,
Size: int64(len(reparse)),
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(reparse)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeReg || hdr.Typeflag == tar.TypeRegA {
bhdr := winio.BackupHeader{
Id: winio.BackupData,
Size: hdr.Size,
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
// Copy all the alternate data streams and return the next non-ADS header.
for {
ahdr, err := t.Next()
if err != nil {
return nil, err
}
if ahdr.Typeflag != tar.TypeReg || !strings.HasPrefix(ahdr.Name, hdr.Name+":") {
return ahdr, nil
}
bhdr := winio.BackupHeader{
Id: winio.BackupAlternateData,
Size: ahdr.Size,
Name: ahdr.Name[len(hdr.Name)+1:] + ":$DATA",
}
err = bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
}
// WriteBackupStreamFromTarFile writes a Win32 backup stream from the current tar file. Since this function may process multiple
// tar file entries in order to collect all the alternate data streams for the file, it returns the next
// tar file that was not processed, or io.EOF is there are no more.
func WriteBackupStreamFromTarFile(w io.Writer, t *tar.Reader, hdr *tar.Header) (*tar.Header, error) {
bw := winio.NewBackupStreamWriter(w)
if sddl, ok := hdr.Winheaders[hdrSecurityDescriptor]; ok {
sd, err := winio.SddlToSecurityDescriptor(sddl)
if err != nil {
return nil, err
}
bhdr := winio.BackupHeader{
Id: winio.BackupSecurity,
Size: int64(len(sd)),
}
err = bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(sd)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeSymlink {
_, isMountPoint := hdr.Winheaders[hdrMountPoint]
rp := winio.ReparsePoint{
Target: hdr.Linkname,
IsMountPoint: isMountPoint,
}
reparse := winio.EncodeReparsePoint(&rp)
bhdr := winio.BackupHeader{
Id: winio.BackupReparseData,
Size: int64(len(reparse)),
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = bw.Write(reparse)
if err != nil {
return nil, err
}
}
if hdr.Typeflag == tar.TypeReg || hdr.Typeflag == tar.TypeRegA {
bhdr := winio.BackupHeader{
Id: winio.BackupData,
Size: hdr.Size,
}
err := bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
// Copy all the alternate data streams and return the next non-ADS header.
for {
ahdr, err := t.Next()
if err != nil {
return nil, err
}
if ahdr.Typeflag != tar.TypeReg || !strings.HasPrefix(ahdr.Name, hdr.Name+":") {
return ahdr, nil
}
bhdr := winio.BackupHeader{
Id: winio.BackupAlternateData,
Size: ahdr.Size,
Name: ahdr.Name[len(hdr.Name)+1:] + ":$DATA",
}
err = bw.WriteHeader(&bhdr)
if err != nil {
return nil, err
}
_, err = io.Copy(bw, t)
if err != nil {
return nil, err
}
}
}