| package docker |
| |
| import ( |
| "archive/tar" |
| "bytes" |
| "fmt" |
| "github.com/dotcloud/docker/utils" |
| "io" |
| "io/ioutil" |
| "os" |
| "os/exec" |
| "path" |
| "path/filepath" |
| ) |
| |
| type Archive io.Reader |
| |
| type Compression uint32 |
| |
| const ( |
| Uncompressed Compression = iota |
| Bzip2 |
| Gzip |
| Xz |
| ) |
| |
| func DetectCompression(source []byte) Compression { |
| sourceLen := len(source) |
| for compression, m := range map[Compression][]byte{ |
| Bzip2: {0x42, 0x5A, 0x68}, |
| Gzip: {0x1F, 0x8B, 0x08}, |
| Xz: {0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00}, |
| } { |
| fail := false |
| if len(m) > sourceLen { |
| utils.Debugf("Len too short") |
| continue |
| } |
| i := 0 |
| for _, b := range m { |
| if b != source[i] { |
| fail = true |
| break |
| } |
| i++ |
| } |
| if !fail { |
| return compression |
| } |
| } |
| return Uncompressed |
| } |
| |
| func (compression *Compression) Flag() string { |
| switch *compression { |
| case Bzip2: |
| return "j" |
| case Gzip: |
| return "z" |
| case Xz: |
| return "J" |
| } |
| return "" |
| } |
| |
| func (compression *Compression) Extension() string { |
| switch *compression { |
| case Uncompressed: |
| return "tar" |
| case Bzip2: |
| return "tar.bz2" |
| case Gzip: |
| return "tar.gz" |
| case Xz: |
| return "tar.xz" |
| } |
| return "" |
| } |
| |
| // Tar creates an archive from the directory at `path`, and returns it as a |
| // stream of bytes. |
| func Tar(path string, compression Compression) (io.Reader, error) { |
| return TarFilter(path, compression, nil) |
| } |
| |
| // Tar creates an archive from the directory at `path`, only including files whose relative |
| // paths are included in `filter`. If `filter` is nil, then all files are included. |
| func TarFilter(path string, compression Compression, filter []string) (io.Reader, error) { |
| args := []string{"tar", "--numeric-owner", "-f", "-", "-C", path} |
| if filter == nil { |
| filter = []string{"."} |
| } |
| for _, f := range filter { |
| args = append(args, "-c"+compression.Flag(), f) |
| } |
| return CmdStream(exec.Command(args[0], args[1:]...)) |
| } |
| |
| // Untar reads a stream of bytes from `archive`, parses it as a tar archive, |
| // and unpacks it into the directory at `path`. |
| // The archive may be compressed with one of the following algorithgms: |
| // identity (uncompressed), gzip, bzip2, xz. |
| // FIXME: specify behavior when target path exists vs. doesn't exist. |
| func Untar(archive io.Reader, path string) error { |
| if archive == nil { |
| return fmt.Errorf("Empty archive") |
| } |
| |
| buf := make([]byte, 10) |
| totalN := 0 |
| for totalN < 10 { |
| if n, err := archive.Read(buf[totalN:]); err != nil { |
| if err == io.EOF { |
| return fmt.Errorf("Tarball too short") |
| } |
| return err |
| } else { |
| totalN += n |
| utils.Debugf("[tar autodetect] n: %d", n) |
| } |
| } |
| compression := DetectCompression(buf) |
| |
| utils.Debugf("Archive compression detected: %s", compression.Extension()) |
| |
| cmd := exec.Command("tar", "--numeric-owner", "-f", "-", "-C", path, "-x"+compression.Flag()) |
| cmd.Stdin = io.MultiReader(bytes.NewReader(buf), archive) |
| // Hardcode locale environment for predictable outcome regardless of host configuration. |
| // (see https://github.com/dotcloud/docker/issues/355) |
| cmd.Env = []string{"LANG=en_US.utf-8", "LC_ALL=en_US.utf-8"} |
| output, err := cmd.CombinedOutput() |
| if err != nil { |
| return fmt.Errorf("%s: %s", err, output) |
| } |
| return nil |
| } |
| |
| // TarUntar is a convenience function which calls Tar and Untar, with |
| // the output of one piped into the other. If either Tar or Untar fails, |
| // TarUntar aborts and returns the error. |
| func TarUntar(src string, filter []string, dst string) error { |
| utils.Debugf("TarUntar(%s %s %s)", src, filter, dst) |
| archive, err := TarFilter(src, Uncompressed, filter) |
| if err != nil { |
| return err |
| } |
| return Untar(archive, dst) |
| } |
| |
| // UntarPath is a convenience function which looks for an archive |
| // at filesystem path `src`, and unpacks it at `dst`. |
| func UntarPath(src, dst string) error { |
| if archive, err := os.Open(src); err != nil { |
| return err |
| } else if err := Untar(archive, dst); err != nil { |
| return err |
| } |
| return nil |
| } |
| |
| // CopyWithTar creates a tar archive of filesystem path `src`, and |
| // unpacks it at filesystem path `dst`. |
| // The archive is streamed directly with fixed buffering and no |
| // intermediary disk IO. |
| // |
| func CopyWithTar(src, dst string) error { |
| srcSt, err := os.Stat(src) |
| if err != nil { |
| return err |
| } |
| if !srcSt.IsDir() { |
| return CopyFileWithTar(src, dst) |
| } |
| // Create dst, copy src's content into it |
| utils.Debugf("Creating dest directory: %s", dst) |
| if err := os.MkdirAll(dst, 0700); err != nil && !os.IsExist(err) { |
| return err |
| } |
| utils.Debugf("Calling TarUntar(%s, %s)", src, dst) |
| return TarUntar(src, nil, dst) |
| } |
| |
| // CopyFileWithTar emulates the behavior of the 'cp' command-line |
| // for a single file. It copies a regular file from path `src` to |
| // path `dst`, and preserves all its metadata. |
| // |
| // If `dst` ends with a trailing slash '/', the final destination path |
| // will be `dst/base(src)`. |
| func CopyFileWithTar(src, dst string) error { |
| utils.Debugf("CopyFileWithTar(%s, %s)", src, dst) |
| srcSt, err := os.Stat(src) |
| if err != nil { |
| return err |
| } |
| if srcSt.IsDir() { |
| return fmt.Errorf("Can't copy a directory") |
| } |
| // Clean up the trailing / |
| if dst[len(dst)-1] == '/' { |
| dst = path.Join(dst, filepath.Base(src)) |
| } |
| // Create the holding directory if necessary |
| if err := os.MkdirAll(filepath.Dir(dst), 0700); err != nil && !os.IsExist(err) { |
| return err |
| } |
| buf := new(bytes.Buffer) |
| tw := tar.NewWriter(buf) |
| hdr, err := tar.FileInfoHeader(srcSt, "") |
| if err != nil { |
| return err |
| } |
| hdr.Name = filepath.Base(dst) |
| if err := tw.WriteHeader(hdr); err != nil { |
| return err |
| } |
| srcF, err := os.Open(src) |
| if err != nil { |
| return err |
| } |
| if _, err := io.Copy(tw, srcF); err != nil { |
| return err |
| } |
| tw.Close() |
| return Untar(buf, filepath.Dir(dst)) |
| } |
| |
| // CmdStream executes a command, and returns its stdout as a stream. |
| // If the command fails to run or doesn't complete successfully, an error |
| // will be returned, including anything written on stderr. |
| func CmdStream(cmd *exec.Cmd) (io.Reader, error) { |
| stdout, err := cmd.StdoutPipe() |
| if err != nil { |
| return nil, err |
| } |
| stderr, err := cmd.StderrPipe() |
| if err != nil { |
| return nil, err |
| } |
| pipeR, pipeW := io.Pipe() |
| errChan := make(chan []byte) |
| // Collect stderr, we will use it in case of an error |
| go func() { |
| errText, e := ioutil.ReadAll(stderr) |
| if e != nil { |
| errText = []byte("(...couldn't fetch stderr: " + e.Error() + ")") |
| } |
| errChan <- errText |
| }() |
| // Copy stdout to the returned pipe |
| go func() { |
| _, err := io.Copy(pipeW, stdout) |
| if err != nil { |
| pipeW.CloseWithError(err) |
| } |
| errText := <-errChan |
| if err := cmd.Wait(); err != nil { |
| pipeW.CloseWithError(fmt.Errorf("%s: %s", err, errText)) |
| } else { |
| pipeW.Close() |
| } |
| }() |
| // Run the command and return the pipe |
| if err := cmd.Start(); err != nil { |
| return nil, err |
| } |
| return pipeR, nil |
| } |
| |
| // NewTempArchive reads the content of src into a temporary file, and returns the contents |
| // of that file as an archive. The archive can only be read once - as soon as reading completes, |
| // the file will be deleted. |
| func NewTempArchive(src Archive, dir string) (*TempArchive, error) { |
| f, err := ioutil.TempFile(dir, "") |
| if err != nil { |
| return nil, err |
| } |
| if _, err := io.Copy(f, src); err != nil { |
| return nil, err |
| } |
| if _, err := f.Seek(0, 0); err != nil { |
| return nil, err |
| } |
| st, err := f.Stat() |
| if err != nil { |
| return nil, err |
| } |
| size := st.Size() |
| return &TempArchive{f, size}, nil |
| } |
| |
| type TempArchive struct { |
| *os.File |
| Size int64 // Pre-computed from Stat().Size() as a convenience |
| } |
| |
| func (archive *TempArchive) Read(data []byte) (int, error) { |
| n, err := archive.File.Read(data) |
| if err != nil { |
| os.Remove(archive.File.Name()) |
| } |
| return n, err |
| } |