package layer // import "github.com/docker/docker/layer" import ( "compress/gzip" "encoding/json" "fmt" "io" "os" "path/filepath" "regexp" "strconv" "strings" "github.com/docker/distribution" "github.com/docker/docker/pkg/ioutils" digest "github.com/opencontainers/go-digest" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) var ( stringIDRegexp = regexp.MustCompile(`^[a-f0-9]{64}(-init)?$`) supportedAlgorithms = []digest.Algorithm{ digest.SHA256, // digest.SHA384, // Currently not used // digest.SHA512, // Currently not used } ) type fileMetadataStore struct { root string } type fileMetadataTransaction struct { store *fileMetadataStore ws *ioutils.AtomicWriteSet } // newFSMetadataStore returns an instance of a metadata store // which is backed by files on disk using the provided root // as the root of metadata files. func newFSMetadataStore(root string) (*fileMetadataStore, error) { if err := os.MkdirAll(root, 0700); err != nil { return nil, err } return &fileMetadataStore{ root: root, }, nil } func (fms *fileMetadataStore) getLayerDirectory(layer ChainID) string { dgst := digest.Digest(layer) return filepath.Join(fms.root, string(dgst.Algorithm()), dgst.Hex()) } func (fms *fileMetadataStore) getLayerFilename(layer ChainID, filename string) string { return filepath.Join(fms.getLayerDirectory(layer), filename) } func (fms *fileMetadataStore) getMountDirectory(mount string) string { return filepath.Join(fms.root, "mounts", mount) } func (fms *fileMetadataStore) getMountFilename(mount, filename string) string { return filepath.Join(fms.getMountDirectory(mount), filename) } func (fms *fileMetadataStore) StartTransaction() (*fileMetadataTransaction, error) { tmpDir := filepath.Join(fms.root, "tmp") if err := os.MkdirAll(tmpDir, 0755); err != nil { return nil, err } ws, err := ioutils.NewAtomicWriteSet(tmpDir) if err != nil { return nil, err } return &fileMetadataTransaction{ store: fms, ws: ws, }, nil } func (fm *fileMetadataTransaction) SetSize(size int64) error { content := fmt.Sprintf("%d", size) return fm.ws.WriteFile("size", []byte(content), 0644) } func (fm *fileMetadataTransaction) SetParent(parent ChainID) error { return fm.ws.WriteFile("parent", []byte(digest.Digest(parent).String()), 0644) } func (fm *fileMetadataTransaction) SetDiffID(diff DiffID) error { return fm.ws.WriteFile("diff", []byte(digest.Digest(diff).String()), 0644) } func (fm *fileMetadataTransaction) SetCacheID(cacheID string) error { return fm.ws.WriteFile("cache-id", []byte(cacheID), 0644) } func (fm *fileMetadataTransaction) SetDescriptor(ref distribution.Descriptor) error { jsonRef, err := json.Marshal(ref) if err != nil { return err } return fm.ws.WriteFile("descriptor.json", jsonRef, 0644) } func (fm *fileMetadataTransaction) TarSplitWriter(compressInput bool) (io.WriteCloser, error) { f, err := fm.ws.FileWriter("tar-split.json.gz", os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0644) if err != nil { return nil, err } var wc io.WriteCloser if compressInput { wc = gzip.NewWriter(f) } else { wc = f } return ioutils.NewWriteCloserWrapper(wc, func() error { wc.Close() return f.Close() }), nil } func (fm *fileMetadataTransaction) Commit(layer ChainID) error { finalDir := fm.store.getLayerDirectory(layer) if err := os.MkdirAll(filepath.Dir(finalDir), 0755); err != nil { return err } return fm.ws.Commit(finalDir) } func (fm *fileMetadataTransaction) Cancel() error { return fm.ws.Cancel() } func (fm *fileMetadataTransaction) String() string { return fm.ws.String() } func (fms *fileMetadataStore) GetSize(layer ChainID) (int64, error) { content, err := os.ReadFile(fms.getLayerFilename(layer, "size")) if err != nil { return 0, err } size, err := strconv.ParseInt(string(content), 10, 64) if err != nil { return 0, err } return size, nil } func (fms *fileMetadataStore) GetParent(layer ChainID) (ChainID, error) { content, err := os.ReadFile(fms.getLayerFilename(layer, "parent")) if err != nil { if os.IsNotExist(err) { return "", nil } return "", err } dgst, err := digest.Parse(strings.TrimSpace(string(content))) if err != nil { return "", err } return ChainID(dgst), nil } func (fms *fileMetadataStore) GetDiffID(layer ChainID) (DiffID, error) { content, err := os.ReadFile(fms.getLayerFilename(layer, "diff")) if err != nil { return "", err } dgst, err := digest.Parse(strings.TrimSpace(string(content))) if err != nil { return "", err } return DiffID(dgst), nil } func (fms *fileMetadataStore) GetCacheID(layer ChainID) (string, error) { contentBytes, err := os.ReadFile(fms.getLayerFilename(layer, "cache-id")) if err != nil { return "", err } content := strings.TrimSpace(string(contentBytes)) if content == "" { return "", errors.Errorf("invalid cache id value") } return content, nil } func (fms *fileMetadataStore) GetDescriptor(layer ChainID) (distribution.Descriptor, error) { content, err := os.ReadFile(fms.getLayerFilename(layer, "descriptor.json")) if err != nil { if os.IsNotExist(err) { // only return empty descriptor to represent what is stored return distribution.Descriptor{}, nil } return distribution.Descriptor{}, err } var ref distribution.Descriptor err = json.Unmarshal(content, &ref) if err != nil { return distribution.Descriptor{}, err } return ref, err } func (fms *fileMetadataStore) TarSplitReader(layer ChainID) (io.ReadCloser, error) { fz, err := os.Open(fms.getLayerFilename(layer, "tar-split.json.gz")) if err != nil { return nil, err } f, err := gzip.NewReader(fz) if err != nil { fz.Close() return nil, err } return ioutils.NewReadCloserWrapper(f, func() error { f.Close() return fz.Close() }), nil } func (fms *fileMetadataStore) SetMountID(mount string, mountID string) error { if err := os.MkdirAll(fms.getMountDirectory(mount), 0755); err != nil { return err } return os.WriteFile(fms.getMountFilename(mount, "mount-id"), []byte(mountID), 0644) } func (fms *fileMetadataStore) SetInitID(mount string, init string) error { if err := os.MkdirAll(fms.getMountDirectory(mount), 0755); err != nil { return err } return os.WriteFile(fms.getMountFilename(mount, "init-id"), []byte(init), 0644) } func (fms *fileMetadataStore) SetMountParent(mount string, parent ChainID) error { if err := os.MkdirAll(fms.getMountDirectory(mount), 0755); err != nil { return err } return os.WriteFile(fms.getMountFilename(mount, "parent"), []byte(digest.Digest(parent).String()), 0644) } func (fms *fileMetadataStore) GetMountID(mount string) (string, error) { contentBytes, err := os.ReadFile(fms.getMountFilename(mount, "mount-id")) if err != nil { return "", err } content := strings.TrimSpace(string(contentBytes)) if !stringIDRegexp.MatchString(content) { return "", errors.New("invalid mount id value") } return content, nil } func (fms *fileMetadataStore) GetInitID(mount string) (string, error) { contentBytes, err := os.ReadFile(fms.getMountFilename(mount, "init-id")) if err != nil { if os.IsNotExist(err) { return "", nil } return "", err } content := strings.TrimSpace(string(contentBytes)) if !stringIDRegexp.MatchString(content) { return "", errors.New("invalid init id value") } return content, nil } func (fms *fileMetadataStore) GetMountParent(mount string) (ChainID, error) { content, err := os.ReadFile(fms.getMountFilename(mount, "parent")) if err != nil { if os.IsNotExist(err) { return "", nil } return "", err } dgst, err := digest.Parse(strings.TrimSpace(string(content))) if err != nil { return "", err } return ChainID(dgst), nil } func (fms *fileMetadataStore) getOrphan() ([]roLayer, error) { var orphanLayers []roLayer for _, algorithm := range supportedAlgorithms { fileInfos, err := os.ReadDir(filepath.Join(fms.root, string(algorithm))) if err != nil { if os.IsNotExist(err) { continue } return nil, err } for _, fi := range fileInfos { if !fi.IsDir() || !strings.HasSuffix(fi.Name(), "-removing") { continue } // At this stage, fi.Name value looks like --removing // Split on '-' to get the digest value. nameSplit := strings.Split(fi.Name(), "-") dgst := digest.NewDigestFromEncoded(algorithm, nameSplit[0]) if err := dgst.Validate(); err != nil { logrus.WithError(err).WithField("digest", string(algorithm)+":"+nameSplit[0]).Debug("ignoring invalid digest") continue } chainFile := filepath.Join(fms.root, string(algorithm), fi.Name(), "cache-id") contentBytes, err := os.ReadFile(chainFile) if err != nil { if !os.IsNotExist(err) { logrus.WithError(err).WithField("digest", dgst).Error("failed to read cache ID") } continue } cacheID := strings.TrimSpace(string(contentBytes)) if cacheID == "" { logrus.Error("invalid cache ID") continue } l := &roLayer{ chainID: ChainID(dgst), cacheID: cacheID, } orphanLayers = append(orphanLayers, *l) } } return orphanLayers, nil } func (fms *fileMetadataStore) List() ([]ChainID, []string, error) { var ids []ChainID for _, algorithm := range supportedAlgorithms { fileInfos, err := os.ReadDir(filepath.Join(fms.root, string(algorithm))) if err != nil { if os.IsNotExist(err) { continue } return nil, nil, err } for _, fi := range fileInfos { if fi.IsDir() && fi.Name() != "mounts" { dgst := digest.NewDigestFromHex(string(algorithm), fi.Name()) if err := dgst.Validate(); err != nil { logrus.Debugf("Ignoring invalid digest %s:%s", algorithm, fi.Name()) } else { ids = append(ids, ChainID(dgst)) } } } } fileInfos, err := os.ReadDir(filepath.Join(fms.root, "mounts")) if err != nil { if os.IsNotExist(err) { return ids, []string{}, nil } return nil, nil, err } var mounts []string for _, fi := range fileInfos { if fi.IsDir() { mounts = append(mounts, fi.Name()) } } return ids, mounts, nil } // Remove layerdb folder if that is marked for removal func (fms *fileMetadataStore) Remove(layer ChainID, cache string) error { dgst := digest.Digest(layer) files, err := os.ReadDir(filepath.Join(fms.root, string(dgst.Algorithm()))) if err != nil { return err } for _, f := range files { if !strings.HasSuffix(f.Name(), "-removing") || !strings.HasPrefix(f.Name(), dgst.Encoded()) { continue } // Make sure that we only remove layerdb folder which points to // requested cacheID dir := filepath.Join(fms.root, string(dgst.Algorithm()), f.Name()) chainFile := filepath.Join(dir, "cache-id") contentBytes, err := os.ReadFile(chainFile) if err != nil { logrus.WithError(err).WithField("file", chainFile).Error("cannot get cache ID") continue } cacheID := strings.TrimSpace(string(contentBytes)) if cacheID != cache { continue } logrus.Debugf("Removing folder: %s", dir) err = os.RemoveAll(dir) if err != nil && !os.IsNotExist(err) { logrus.WithError(err).WithField("name", f.Name()).Error("cannot remove layer") continue } } return nil } func (fms *fileMetadataStore) RemoveMount(mount string) error { return os.RemoveAll(fms.getMountDirectory(mount)) }