diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/microsoft/go-winio/backup.go')
| -rw-r--r-- | Godeps/_workspace/src/github.com/microsoft/go-winio/backup.go | 266 |
1 files changed, 0 insertions, 266 deletions
diff --git a/Godeps/_workspace/src/github.com/microsoft/go-winio/backup.go b/Godeps/_workspace/src/github.com/microsoft/go-winio/backup.go deleted file mode 100644 index 864935175..000000000 --- a/Godeps/_workspace/src/github.com/microsoft/go-winio/backup.go +++ /dev/null @@ -1,266 +0,0 @@ -package winio - -import ( - "encoding/binary" - "errors" - "fmt" - "io" - "io/ioutil" - "os" - "runtime" - "syscall" - "unicode/utf16" -) - -//sys backupRead(h syscall.Handle, b []byte, bytesRead *uint32, abort bool, processSecurity bool, context *uintptr) (err error) = BackupRead -//sys backupWrite(h syscall.Handle, b []byte, bytesWritten *uint32, abort bool, processSecurity bool, context *uintptr) (err error) = BackupWrite - -const ( - BackupData = uint32(iota + 1) - BackupEaData - BackupSecurity - BackupAlternateData - BackupLink - BackupPropertyData - BackupObjectId - BackupReparseData - BackupSparseBlock - BackupTxfsData -) - -const ( - StreamSparseAttributes = uint32(8) -) - -const ( - WRITE_DAC = 0x40000 - WRITE_OWNER = 0x80000 - ACCESS_SYSTEM_SECURITY = 0x1000000 -) - -// BackupHeader represents a backup stream of a file. -type BackupHeader struct { - Id uint32 // The backup stream ID - Attributes uint32 // Stream attributes - Size int64 // The size of the stream in bytes - Name string // The name of the stream (for BackupAlternateData only). - Offset int64 // The offset of the stream in the file (for BackupSparseBlock only). -} - -type win32StreamId struct { - StreamId uint32 - Attributes uint32 - Size uint64 - NameSize uint32 -} - -// BackupStreamReader reads from a stream produced by the BackupRead Win32 API and produces a series -// of BackupHeader values. -type BackupStreamReader struct { - r io.Reader - bytesLeft int64 -} - -// NewBackupStreamReader produces a BackupStreamReader from any io.Reader. -func NewBackupStreamReader(r io.Reader) *BackupStreamReader { - return &BackupStreamReader{r, 0} -} - -// Next returns the next backup stream and prepares for calls to Write(). It skips the remainder of the current stream if -// it was not completely read. -func (r *BackupStreamReader) Next() (*BackupHeader, error) { - if r.bytesLeft > 0 { - if _, err := io.Copy(ioutil.Discard, r); err != nil { - return nil, err - } - } - var wsi win32StreamId - if err := binary.Read(r.r, binary.LittleEndian, &wsi); err != nil { - return nil, err - } - hdr := &BackupHeader{ - Id: wsi.StreamId, - Attributes: wsi.Attributes, - Size: int64(wsi.Size), - } - if wsi.NameSize != 0 { - name := make([]uint16, int(wsi.NameSize/2)) - if err := binary.Read(r.r, binary.LittleEndian, name); err != nil { - return nil, err - } - hdr.Name = syscall.UTF16ToString(name) - } - if wsi.StreamId == BackupSparseBlock { - if err := binary.Read(r.r, binary.LittleEndian, &hdr.Offset); err != nil { - return nil, err - } - hdr.Size -= 8 - } - r.bytesLeft = hdr.Size - return hdr, nil -} - -// Read reads from the current backup stream. -func (r *BackupStreamReader) Read(b []byte) (int, error) { - if r.bytesLeft == 0 { - return 0, io.EOF - } - if int64(len(b)) > r.bytesLeft { - b = b[:r.bytesLeft] - } - n, err := r.r.Read(b) - r.bytesLeft -= int64(n) - if err == io.EOF { - err = io.ErrUnexpectedEOF - } else if r.bytesLeft == 0 && err == nil { - err = io.EOF - } - return n, err -} - -// BackupStreamWriter writes a stream compatible with the BackupWrite Win32 API. -type BackupStreamWriter struct { - w io.Writer - bytesLeft int64 -} - -// NewBackupStreamWriter produces a BackupStreamWriter on top of an io.Writer. -func NewBackupStreamWriter(w io.Writer) *BackupStreamWriter { - return &BackupStreamWriter{w, 0} -} - -// WriteHeader writes the next backup stream header and prepares for calls to Write(). -func (w *BackupStreamWriter) WriteHeader(hdr *BackupHeader) error { - if w.bytesLeft != 0 { - return fmt.Errorf("missing %d bytes", w.bytesLeft) - } - name := utf16.Encode([]rune(hdr.Name)) - wsi := win32StreamId{ - StreamId: hdr.Id, - Attributes: hdr.Attributes, - Size: uint64(hdr.Size), - NameSize: uint32(len(name) * 2), - } - if hdr.Id == BackupSparseBlock { - // Include space for the int64 block offset - wsi.Size += 8 - } - if err := binary.Write(w.w, binary.LittleEndian, &wsi); err != nil { - return err - } - if len(name) != 0 { - if err := binary.Write(w.w, binary.LittleEndian, name); err != nil { - return err - } - } - if hdr.Id == BackupSparseBlock { - if err := binary.Write(w.w, binary.LittleEndian, hdr.Offset); err != nil { - return err - } - } - w.bytesLeft = hdr.Size - return nil -} - -// Write writes to the current backup stream. -func (w *BackupStreamWriter) Write(b []byte) (int, error) { - if w.bytesLeft < int64(len(b)) { - return 0, fmt.Errorf("too many bytes by %d", int64(len(b))-w.bytesLeft) - } - n, err := w.w.Write(b) - w.bytesLeft -= int64(n) - return n, err -} - -// BackupFileReader provides an io.ReadCloser interface on top of the BackupRead Win32 API. -type BackupFileReader struct { - f *os.File - includeSecurity bool - ctx uintptr -} - -// NewBackupFileReader returns a new BackupFileReader from a file handle. If includeSecurity is true, -// Read will attempt to read the security descriptor of the file. -func NewBackupFileReader(f *os.File, includeSecurity bool) *BackupFileReader { - r := &BackupFileReader{f, includeSecurity, 0} - runtime.SetFinalizer(r, func(r *BackupFileReader) { r.Close() }) - return r -} - -// Read reads a backup stream from the file by calling the Win32 API BackupRead(). -func (r *BackupFileReader) Read(b []byte) (int, error) { - var bytesRead uint32 - err := backupRead(syscall.Handle(r.f.Fd()), b, &bytesRead, false, r.includeSecurity, &r.ctx) - if err != nil { - return 0, &os.PathError{"BackupRead", r.f.Name(), err} - } - if bytesRead == 0 { - return 0, io.EOF - } - return int(bytesRead), nil -} - -// Close frees Win32 resources associated with the BackupFileReader. It does not close -// the underlying file. -func (r *BackupFileReader) Close() error { - if r.ctx != 0 { - backupRead(syscall.Handle(r.f.Fd()), nil, nil, true, false, &r.ctx) - r.ctx = 0 - } - return nil -} - -// BackupFileWriter provides an io.WriteCloser interface on top of the BackupWrite Win32 API. -type BackupFileWriter struct { - f *os.File - includeSecurity bool - ctx uintptr -} - -// NewBackupFileWrtier returns a new BackupFileWriter from a file handle. If includeSecurity is true, -// Write() will attempt to restore the security descriptor from the stream. -func NewBackupFileWriter(f *os.File, includeSecurity bool) *BackupFileWriter { - w := &BackupFileWriter{f, includeSecurity, 0} - runtime.SetFinalizer(w, func(w *BackupFileWriter) { w.Close() }) - return w -} - -// Write restores a portion of the file using the provided backup stream. -func (w *BackupFileWriter) Write(b []byte) (int, error) { - var bytesWritten uint32 - err := backupWrite(syscall.Handle(w.f.Fd()), b, &bytesWritten, false, w.includeSecurity, &w.ctx) - if err != nil { - return 0, &os.PathError{"BackupWrite", w.f.Name(), err} - } - if int(bytesWritten) != len(b) { - return int(bytesWritten), errors.New("not all bytes could be written") - } - return len(b), nil -} - -// Close frees Win32 resources associated with the BackupFileWriter. It does not -// close the underlying file. -func (w *BackupFileWriter) Close() error { - if w.ctx != 0 { - backupWrite(syscall.Handle(w.f.Fd()), nil, nil, true, false, &w.ctx) - w.ctx = 0 - } - return nil -} - -// OpenForBackup opens a file or directory, potentially skipping access checks if the backup -// or restore privileges have been acquired. -// -// If the file opened was a directory, it cannot be used with Readdir(). -func OpenForBackup(path string, access uint32, share uint32, createmode uint32) (*os.File, error) { - winPath, err := syscall.UTF16FromString(path) - if err != nil { - return nil, err - } - h, err := syscall.CreateFile(&winPath[0], access, share, nil, createmode, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0) - if err != nil { - err = &os.PathError{Op: "open", Path: path, Err: err} - return nil, err - } - return os.NewFile(uintptr(h), path), nil -} |