123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353 |
- // +build windows
- package backuptar
- import (
- "encoding/base64"
- "errors"
- "fmt"
- "io"
- "io/ioutil"
- "path/filepath"
- "strconv"
- "strings"
- "syscall"
- "time"
- "github.com/Microsoft/go-winio"
- "github.com/Microsoft/go-winio/archive/tar" // until archive/tar supports pax extensions in its interface
- )
- 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
- )
- const (
- hdrFileAttributes = "fileattr"
- hdrSecurityDescriptor = "sd"
- hdrRawSecurityDescriptor = "rawsd"
- hdrMountPoint = "mountpoint"
- )
- func writeZeroes(w io.Writer, count int64) error {
- buf := make([]byte, 8192)
- c := len(buf)
- for i := int64(0); i < count; i += int64(c) {
- if int64(c) > count-i {
- c = int(count - i)
- }
- _, err := w.Write(buf[:c])
- if err != nil {
- return err
- }
- }
- return nil
- }
- func copySparse(t *tar.Writer, br *winio.BackupStreamReader) error {
- curOffset := int64(0)
- for {
- bhdr, err := br.Next()
- if err == io.EOF {
- err = io.ErrUnexpectedEOF
- }
- if err != nil {
- return err
- }
- if bhdr.Id != winio.BackupSparseBlock {
- return fmt.Errorf("unexpected stream %d", bhdr.Id)
- }
- // archive/tar does not support writing sparse files
- // so just write zeroes to catch up to the current offset.
- err = writeZeroes(t, bhdr.Offset-curOffset)
- if bhdr.Size == 0 {
- break
- }
- n, err := io.Copy(t, br)
- if err != nil {
- return err
- }
- curOffset = bhdr.Offset + n
- }
- return nil
- }
- // BasicInfoHeader creates a tar header from basic file information.
- func BasicInfoHeader(name string, size int64, fileInfo *winio.FileBasicInfo) *tar.Header {
- hdr := &tar.Header{
- Name: filepath.ToSlash(name),
- Size: size,
- Typeflag: tar.TypeReg,
- ModTime: time.Unix(0, fileInfo.LastWriteTime.Nanoseconds()),
- ChangeTime: time.Unix(0, fileInfo.ChangeTime.Nanoseconds()),
- AccessTime: time.Unix(0, fileInfo.LastAccessTime.Nanoseconds()),
- CreationTime: time.Unix(0, fileInfo.CreationTime.Nanoseconds()),
- Winheaders: make(map[string]string),
- }
- hdr.Winheaders[hdrFileAttributes] = fmt.Sprintf("%d", fileInfo.FileAttributes)
- if (fileInfo.FileAttributes & syscall.FILE_ATTRIBUTE_DIRECTORY) != 0 {
- hdr.Mode |= c_ISDIR
- hdr.Size = 0
- hdr.Typeflag = tar.TypeDir
- }
- return hdr
- }
- // WriteTarFileFromBackupStream writes a file to a tar writer using data from a Win32 backup stream.
- //
- // This encodes Win32 metadata as tar pax vendor extensions starting with MSWINDOWS.
- //
- // The additional Win32 metadata is:
- //
- // MSWINDOWS.fileattr: The Win32 file attributes, as a decimal value
- //
- // MSWINDOWS.rawsd: The Win32 security descriptor, in raw binary format
- //
- // MSWINDOWS.mountpoint: If present, this is a mount point and not a symlink, even though the type is '2' (symlink)
- func WriteTarFileFromBackupStream(t *tar.Writer, r io.Reader, name string, size int64, fileInfo *winio.FileBasicInfo) error {
- name = filepath.ToSlash(name)
- hdr := BasicInfoHeader(name, size, fileInfo)
- br := winio.NewBackupStreamReader(r)
- var dataHdr *winio.BackupHeader
- for dataHdr == nil {
- bhdr, err := br.Next()
- if err == io.EOF {
- break
- }
- if err != nil {
- return err
- }
- switch bhdr.Id {
- case winio.BackupData:
- hdr.Mode |= c_ISREG
- dataHdr = bhdr
- case winio.BackupSecurity:
- sd, err := ioutil.ReadAll(br)
- if err != nil {
- return err
- }
- hdr.Winheaders[hdrRawSecurityDescriptor] = base64.StdEncoding.EncodeToString(sd)
- case winio.BackupReparseData:
- hdr.Mode |= c_ISLNK
- hdr.Typeflag = tar.TypeSymlink
- reparseBuffer, err := ioutil.ReadAll(br)
- rp, err := winio.DecodeReparsePoint(reparseBuffer)
- if err != nil {
- return err
- }
- if rp.IsMountPoint {
- hdr.Winheaders[hdrMountPoint] = "1"
- }
- hdr.Linkname = rp.Target
- case winio.BackupEaData, winio.BackupLink, winio.BackupPropertyData, winio.BackupObjectId, winio.BackupTxfsData:
- // ignore these streams
- default:
- return fmt.Errorf("%s: unknown stream ID %d", name, bhdr.Id)
- }
- }
- err := t.WriteHeader(hdr)
- if err != nil {
- return err
- }
- if dataHdr != nil {
- // A data stream was found. Copy the data.
- if (dataHdr.Attributes & winio.StreamSparseAttributes) == 0 {
- if size != dataHdr.Size {
- return fmt.Errorf("%s: mismatch between file size %d and header size %d", name, size, dataHdr.Size)
- }
- _, err = io.Copy(t, br)
- if err != nil {
- return err
- }
- } else {
- err = copySparse(t, br)
- if err != nil {
- return err
- }
- }
- }
- // Look for streams after the data stream. The only ones we handle are alternate data streams.
- // Other streams may have metadata that could be serialized, but the tar header has already
- // been written. In practice, this means that we don't get EA or TXF metadata.
- for {
- bhdr, err := br.Next()
- if err == io.EOF {
- break
- }
- if err != nil {
- return err
- }
- switch bhdr.Id {
- case winio.BackupAlternateData:
- altName := bhdr.Name
- if strings.HasSuffix(altName, ":$DATA") {
- altName = altName[:len(altName)-len(":$DATA")]
- }
- if (bhdr.Attributes & winio.StreamSparseAttributes) == 0 {
- hdr = &tar.Header{
- Name: name + altName,
- Mode: hdr.Mode,
- Typeflag: tar.TypeReg,
- Size: bhdr.Size,
- ModTime: hdr.ModTime,
- AccessTime: hdr.AccessTime,
- ChangeTime: hdr.ChangeTime,
- }
- err = t.WriteHeader(hdr)
- if err != nil {
- return err
- }
- _, err = io.Copy(t, br)
- if err != nil {
- return err
- }
- } else {
- // Unsupported for now, since the size of the alternate stream is not present
- // in the backup stream until after the data has been read.
- return errors.New("tar of sparse alternate data streams is unsupported")
- }
- case winio.BackupEaData, winio.BackupLink, winio.BackupPropertyData, winio.BackupObjectId, winio.BackupTxfsData:
- // ignore these streams
- default:
- return fmt.Errorf("%s: unknown stream ID %d after data", name, bhdr.Id)
- }
- }
- return nil
- }
- // FileInfoFromHeader retrieves basic Win32 file information from a tar header, using the additional metadata written by
- // WriteTarFileFromBackupStream.
- func FileInfoFromHeader(hdr *tar.Header) (name string, size int64, fileInfo *winio.FileBasicInfo, err error) {
- name = hdr.Name
- if hdr.Typeflag == tar.TypeReg || hdr.Typeflag == tar.TypeRegA {
- size = hdr.Size
- }
- fileInfo = &winio.FileBasicInfo{
- LastAccessTime: syscall.NsecToFiletime(hdr.AccessTime.UnixNano()),
- LastWriteTime: syscall.NsecToFiletime(hdr.ModTime.UnixNano()),
- ChangeTime: syscall.NsecToFiletime(hdr.ChangeTime.UnixNano()),
- CreationTime: syscall.NsecToFiletime(hdr.CreationTime.UnixNano()),
- }
- if attrStr, ok := hdr.Winheaders[hdrFileAttributes]; ok {
- attr, err := strconv.ParseUint(attrStr, 10, 32)
- if err != nil {
- return "", 0, nil, err
- }
- fileInfo.FileAttributes = uintptr(attr)
- } else {
- if hdr.Typeflag == tar.TypeDir {
- fileInfo.FileAttributes |= syscall.FILE_ATTRIBUTE_DIRECTORY
- }
- }
- return
- }
- // 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):] + ":$DATA",
- }
- err = bw.WriteHeader(&bhdr)
- if err != nil {
- return nil, err
- }
- _, err = io.Copy(bw, t)
- if err != nil {
- return nil, err
- }
- }
- }
|