package tarsum import ( "bytes" "compress/gzip" "crypto/sha256" "encoding/hex" "hash" "io" "log" "sort" "strconv" "strings" "github.com/docker/docker/vendor/src/code.google.com/p/go/src/pkg/archive/tar" ) type TarSum struct { io.Reader tarR *tar.Reader tarW *tar.Writer gz writeCloseFlusher bufTar *bytes.Buffer bufGz *bytes.Buffer h hash.Hash sums map[string]string currentFile string finished bool first bool DisableCompression bool } type writeCloseFlusher interface { io.WriteCloser Flush() error } type nopCloseFlusher struct { io.Writer } func (n *nopCloseFlusher) Close() error { return nil } func (n *nopCloseFlusher) Flush() error { return nil } func (ts *TarSum) encodeHeader(h *tar.Header) error { for _, elem := range [][2]string{ {"name", h.Name}, {"mode", strconv.Itoa(int(h.Mode))}, {"uid", strconv.Itoa(h.Uid)}, {"gid", strconv.Itoa(h.Gid)}, {"size", strconv.Itoa(int(h.Size))}, {"mtime", strconv.Itoa(int(h.ModTime.UTC().Unix()))}, {"typeflag", string([]byte{h.Typeflag})}, {"linkname", h.Linkname}, {"uname", h.Uname}, {"gname", h.Gname}, {"devmajor", strconv.Itoa(int(h.Devmajor))}, {"devminor", strconv.Itoa(int(h.Devminor))}, // {"atime", strconv.Itoa(int(h.AccessTime.UTC().Unix()))}, // {"ctime", strconv.Itoa(int(h.ChangeTime.UTC().Unix()))}, } { if _, err := ts.h.Write([]byte(elem[0] + elem[1])); err != nil { return err } } return nil } func (ts *TarSum) Read(buf []byte) (int, error) { if ts.gz == nil { ts.bufTar = bytes.NewBuffer([]byte{}) ts.bufGz = bytes.NewBuffer([]byte{}) ts.tarR = tar.NewReader(ts.Reader) ts.tarW = tar.NewWriter(ts.bufTar) if !ts.DisableCompression { ts.gz = gzip.NewWriter(ts.bufGz) } else { ts.gz = &nopCloseFlusher{Writer: ts.bufGz} } ts.h = sha256.New() ts.h.Reset() ts.first = true ts.sums = make(map[string]string) } if ts.finished { return ts.bufGz.Read(buf) } buf2 := make([]byte, len(buf), cap(buf)) n, err := ts.tarR.Read(buf2) if err != nil { if err == io.EOF { if _, err := ts.h.Write(buf2[:n]); err != nil { return 0, err } if !ts.first { ts.sums[ts.currentFile] = hex.EncodeToString(ts.h.Sum(nil)) ts.h.Reset() } else { ts.first = false } currentHeader, err := ts.tarR.Next() if err != nil { if err == io.EOF { if err := ts.gz.Close(); err != nil { return 0, err } ts.finished = true return n, nil } return n, err } ts.currentFile = strings.TrimSuffix(strings.TrimPrefix(currentHeader.Name, "./"), "/") if err := ts.encodeHeader(currentHeader); err != nil { return 0, err } if err := ts.tarW.WriteHeader(currentHeader); err != nil { return 0, err } if _, err := ts.tarW.Write(buf2[:n]); err != nil { return 0, err } ts.tarW.Flush() if _, err := io.Copy(ts.gz, ts.bufTar); err != nil { return 0, err } ts.gz.Flush() return ts.bufGz.Read(buf) } return n, err } // Filling the hash buffer if _, err = ts.h.Write(buf2[:n]); err != nil { return 0, err } // Filling the tar writter if _, err = ts.tarW.Write(buf2[:n]); err != nil { return 0, err } ts.tarW.Flush() // Filling the gz writter if _, err = io.Copy(ts.gz, ts.bufTar); err != nil { return 0, err } ts.gz.Flush() return ts.bufGz.Read(buf) } func (ts *TarSum) Sum(extra []byte) string { var sums []string for _, sum := range ts.sums { sums = append(sums, sum) } sort.Strings(sums) h := sha256.New() if extra != nil { h.Write(extra) } for _, sum := range sums { log.Printf("-->%s<--", sum) h.Write([]byte(sum)) } checksum := "tarsum+sha256:" + hex.EncodeToString(h.Sum(nil)) log.Printf("checksum processed: %s", checksum) return checksum } func (ts *TarSum) GetSums() map[string]string { return ts.sums }