Golang errors.Errorf函数代码示例

func (node Node) MarshalJSON() ([]byte, error) {
	if node.ModTime.Year() < 0 || node.ModTime.Year() > 9999 {
		err := errors.Errorf("node %v has invalid ModTime year %d: %v",
			node.Path, node.ModTime.Year(), node.ModTime)
		return nil, err
	}

	if node.ChangeTime.Year() < 0 || node.ChangeTime.Year() > 9999 {
		err := errors.Errorf("node %v has invalid ChangeTime year %d: %v",
			node.Path, node.ChangeTime.Year(), node.ChangeTime)
		return nil, err
	}

	if node.AccessTime.Year() < 0 || node.AccessTime.Year() > 9999 {
		err := errors.Errorf("node %v has invalid AccessTime year %d: %v",
			node.Path, node.AccessTime.Year(), node.AccessTime)
		return nil, err
	}

	type nodeJSON Node
	nj := nodeJSON(node)
	name := strconv.Quote(node.Name)
	nj.Name = name[1 : len(name)-1]

	return json.Marshal(nj)
}

func (r *SFTP) mkdirAll(dir string, mode os.FileMode) error {
	// check if directory already exists
	fi, err := r.c.Lstat(dir)
	if err == nil {
		if fi.IsDir() {
			return nil
		}

		return errors.Errorf("mkdirAll(%s): entry exists but is not a directory", dir)
	}

	// create parent directories
	errMkdirAll := r.mkdirAll(path.Dir(dir), backend.Modes.Dir)

	// create directory
	errMkdir := r.c.Mkdir(dir)

	// test if directory was created successfully
	fi, err = r.c.Lstat(dir)
	if err != nil {
		// return previous errors
		return errors.Errorf("mkdirAll(%s): unable to create directories: %v, %v", dir, errMkdirAll, errMkdir)
	}

	if !fi.IsDir() {
		return errors.Errorf("mkdirAll(%s): entry exists but is not a directory", dir)
	}

	// set mode
	return r.c.Chmod(dir, mode)
}

func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) {
	debug.Log("checking tree %v", id.Str())

	var blobs []restic.ID

	for _, node := range tree.Nodes {
		switch node.Type {
		case "file":
			if node.Content == nil {
				errs = append(errs, Error{TreeID: id, Err: errors.Errorf("file %q has nil blob list", node.Name)})
			}

			for b, blobID := range node.Content {
				if blobID.IsNull() {
					errs = append(errs, Error{TreeID: id, Err: errors.Errorf("file %q blob %d has null ID", node.Name, b)})
					continue
				}
				blobs = append(blobs, blobID)
			}
		case "dir":
			if node.Subtree == nil {
				errs = append(errs, Error{TreeID: id, Err: errors.Errorf("dir node %q has no subtree", node.Name)})
				continue
			}

			if node.Subtree.IsNull() {
				errs = append(errs, Error{TreeID: id, Err: errors.Errorf("dir node %q subtree id is null", node.Name)})
				continue
			}

		case "symlink", "socket", "chardev", "dev", "fifo":
			// nothing to check

		default:
			errs = append(errs, Error{TreeID: id, Err: errors.Errorf("node %q with invalid type %q", node.Name, node.Type)})
		}

		if node.Name == "" {
			errs = append(errs, Error{TreeID: id, Err: errors.New("node with empty name")})
		}
	}

	for _, blobID := range blobs {
		c.blobRefs.Lock()
		c.blobRefs.M[blobID]++
		debug.Log("blob %v refcount %d", blobID.Str(), c.blobRefs.M[blobID])
		c.blobRefs.Unlock()

		if !c.blobs.Has(blobID) {
			debug.Log("tree %v references blob %v which isn't contained in index", id.Str(), blobID.Str())

			errs = append(errs, Error{TreeID: id, BlobID: blobID, Err: errors.New("not found in index")})
		}
	}

	return errs
}

// FindLatestSnapshot finds latest snapshot with optional target/directory and source filters
func FindLatestSnapshot(repo Repository, targets []string, source string) (ID, error) {
	var (
		latest   time.Time
		latestID ID
		found    bool
	)

	for snapshotID := range repo.List(SnapshotFile, make(chan struct{})) {
		snapshot, err := LoadSnapshot(repo, snapshotID)
		if err != nil {
			return ID{}, errors.Errorf("Error listing snapshot: %v", err)
		}
		if snapshot.Time.After(latest) && SamePaths(snapshot.Paths, targets) && (source == "" || source == snapshot.Hostname) {
			latest = snapshot.Time
			latestID = snapshotID
			found = true
		}
	}

	if !found {
		return ID{}, ErrNoSnapshotFound
	}

	return latestID, nil
}

// Lookup queries the index for the blob ID and returns a restic.PackedBlob.
func (idx *Index) Lookup(id restic.ID, tpe restic.BlobType) (blobs []restic.PackedBlob, err error) {
	idx.m.Lock()
	defer idx.m.Unlock()

	h := restic.BlobHandle{ID: id, Type: tpe}

	if packs, ok := idx.pack[h]; ok {
		blobs = make([]restic.PackedBlob, 0, len(packs))

		for _, p := range packs {
			debug.Log("id %v found in pack %v at %d, length %d",
				id.Str(), p.packID.Str(), p.offset, p.length)

			blob := restic.PackedBlob{
				Blob: restic.Blob{
					Type:   tpe,
					Length: p.length,
					ID:     id,
					Offset: p.offset,
				},
				PackID: p.packID,
			}

			blobs = append(blobs, blob)
		}

		return blobs, nil
	}

	debug.Log("id %v not found", id.Str())
	return nil, errors.Errorf("id %v not found in index", id)
}

// writeHeader constructs and writes the header to wr.
func (p *Packer) writeHeader(wr io.Writer) (bytesWritten uint, err error) {
	for _, b := range p.blobs {
		entry := headerEntry{
			Length: uint32(b.Length),
			ID:     b.ID,
		}

		switch b.Type {
		case restic.DataBlob:
			entry.Type = 0
		case restic.TreeBlob:
			entry.Type = 1
		default:
			return 0, errors.Errorf("invalid blob type %v", b.Type)
		}

		err := binary.Write(wr, binary.LittleEndian, entry)
		if err != nil {
			return bytesWritten, errors.Wrap(err, "binary.Write")
		}

		bytesWritten += entrySize
	}

	return
}

// Save stores data in the backend at the handle.
func (b *restBackend) Save(h restic.Handle, p []byte) (err error) {
	if err := h.Valid(); err != nil {
		return err
	}

	<-b.connChan
	resp, err := b.client.Post(restPath(b.url, h), "binary/octet-stream", bytes.NewReader(p))
	b.connChan <- struct{}{}

	if resp != nil {
		defer func() {
			io.Copy(ioutil.Discard, resp.Body)
			e := resp.Body.Close()

			if err == nil {
				err = errors.Wrap(e, "Close")
			}
		}()
	}

	if err != nil {
		return errors.Wrap(err, "client.Post")
	}

	if resp.StatusCode != 200 {
		return errors.Errorf("unexpected HTTP response code %v", resp.StatusCode)
	}

	return nil
}

// Valid returns an error if h is not valid.
func (h Handle) Valid() error {
	if h.Type == "" {
		return errors.New("type is empty")
	}

	switch h.Type {
	case DataFile:
	case KeyFile:
	case LockFile:
	case SnapshotFile:
	case IndexFile:
	case ConfigFile:
	default:
		return errors.Errorf("invalid Type %q", h.Type)
	}

	if h.Type == ConfigFile {
		return nil
	}

	if h.Name == "" {
		return errors.New("invalid Name")
	}

	return nil
}

// Stat returns information about a blob.
func (b *restBackend) Stat(h restic.Handle) (restic.FileInfo, error) {
	if err := h.Valid(); err != nil {
		return restic.FileInfo{}, err
	}

	<-b.connChan
	resp, err := b.client.Head(restPath(b.url, h))
	b.connChan <- struct{}{}
	if err != nil {
		return restic.FileInfo{}, errors.Wrap(err, "client.Head")
	}

	io.Copy(ioutil.Discard, resp.Body)
	if err = resp.Body.Close(); err != nil {
		return restic.FileInfo{}, errors.Wrap(err, "Close")
	}

	if resp.StatusCode != 200 {
		return restic.FileInfo{}, errors.Errorf("unexpected HTTP response code %v", resp.StatusCode)
	}

	if resp.ContentLength < 0 {
		return restic.FileInfo{}, errors.New("negative content length")
	}

	bi := restic.FileInfo{
		Size: resp.ContentLength,
	}

	return bi, nil
}

// FindBlob returns a list of packs and positions the blob can be found in.
func (idx *Index) FindBlob(h restic.BlobHandle) ([]Location, error) {
	blob, ok := idx.Blobs[h]
	if !ok {
		return nil, ErrBlobNotFound
	}

	result := make([]Location, 0, len(blob.Packs))
	for packID := range blob.Packs {
		pack, ok := idx.Packs[packID]
		if !ok {
			return nil, errors.Errorf("pack %v not found in index", packID.Str())
		}

		for _, entry := range pack.Entries {
			if entry.Type != h.Type {
				continue
			}

			if !entry.ID.Equal(h.ID) {
				continue
			}

			loc := Location{PackID: packID, Blob: entry}
			result = append(result, loc)
		}
	}

	return result, nil
}

// Rename temp file to final name according to type and name.
func (r *SFTP) renameFile(oldname string, t restic.FileType, name string) error {
	filename := r.filename(t, name)

	// create directories if necessary
	if t == restic.DataFile {
		err := r.mkdirAll(path.Dir(filename), backend.Modes.Dir)
		if err != nil {
			return err
		}
	}

	// test if new file exists
	if _, err := r.c.Lstat(filename); err == nil {
		return errors.Errorf("Close(): file %v already exists", filename)
	}

	err := r.c.Rename(oldname, filename)
	if err != nil {
		return errors.Wrap(err, "Rename")
	}

	// set mode to read-only
	fi, err := r.c.Lstat(filename)
	if err != nil {
		return errors.Wrap(err, "Lstat")
	}

	err = r.c.Chmod(filename, fi.Mode()&os.FileMode(^uint32(0222)))
	return errors.Wrap(err, "Chmod")
}

// savePacker stores p in the backend.
func (r *Repository) savePacker(p *pack.Packer) error {
	debug.Log("save packer with %d blobs\n", p.Count())
	n, err := p.Finalize()
	if err != nil {
		return err
	}

	tmpfile := p.Writer().(*os.File)
	f, err := fs.Open(tmpfile.Name())
	if err != nil {
		return errors.Wrap(err, "Open")
	}

	data := make([]byte, n)
	m, err := io.ReadFull(f, data)
	if err != nil {
		return errors.Wrap(err, "ReadFul")
	}

	if uint(m) != n {
		return errors.Errorf("read wrong number of bytes from %v: want %v, got %v", tmpfile.Name(), n, m)
	}

	if err = f.Close(); err != nil {
		return errors.Wrap(err, "Close")
	}

	id := restic.Hash(data)
	h := restic.Handle{Type: restic.DataFile, Name: id.String()}

	err = r.be.Save(h, data)
	if err != nil {
		debug.Log("Save(%v) error: %v", h, err)
		return err
	}

	debug.Log("saved as %v", h)

	err = fs.Remove(tmpfile.Name())
	if err != nil {
		return errors.Wrap(err, "Remove")
	}

	// update blobs in the index
	for _, b := range p.Blobs() {
		debug.Log("  updating blob %v to pack %v", b.ID.Str(), id.Str())
		r.idx.Current().Store(restic.PackedBlob{
			Blob: restic.Blob{
				Type:   b.Type,
				ID:     b.ID,
				Offset: b.Offset,
				Length: uint(b.Length),
			},
			PackID: id,
		})
	}

	return nil
}

// checkPack reads a pack and checks the integrity of all blobs.
func checkPack(r restic.Repository, id restic.ID) error {
	debug.Log("checking pack %v", id.Str())
	h := restic.Handle{Type: restic.DataFile, Name: id.String()}
	buf, err := backend.LoadAll(r.Backend(), h, nil)
	if err != nil {
		return err
	}

	hash := restic.Hash(buf)
	if !hash.Equal(id) {
		debug.Log("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
		return errors.Errorf("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
	}

	blobs, err := pack.List(r.Key(), bytes.NewReader(buf), int64(len(buf)))
	if err != nil {
		return err
	}

	var errs []error
	for i, blob := range blobs {
		debug.Log("  check blob %d: %v", i, blob.ID.Str())

		plainBuf := make([]byte, blob.Length)
		n, err := crypto.Decrypt(r.Key(), plainBuf, buf[blob.Offset:blob.Offset+blob.Length])
		if err != nil {
			debug.Log("  error decrypting blob %v: %v", blob.ID.Str(), err)
			errs = append(errs, errors.Errorf("blob %v: %v", i, err))
			continue
		}
		plainBuf = plainBuf[:n]

		hash := restic.Hash(plainBuf)
		if !hash.Equal(blob.ID) {
			debug.Log("  Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str())
			errs = append(errs, errors.Errorf("Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str()))
			continue
		}
	}

	if len(errs) > 0 {
		return errors.Errorf("pack %v contains %v errors: %v", id.Str(), len(errs), errs)
	}

	return nil
}

// Decrypt verifies and decrypts the ciphertext. Ciphertext must be in the form
// IV || Ciphertext || MAC. plaintext and ciphertext may point to (exactly) the
// same slice.
func Decrypt(ks *Key, plaintext []byte, ciphertextWithMac []byte) (int, error) {
	if !ks.Valid() {
		return 0, errors.New("invalid key")
	}

	// check for plausible length
	if len(ciphertextWithMac) < ivSize+macSize {
		panic("trying to decrypt invalid data: ciphertext too small")
	}

	// check buffer length for plaintext
	plaintextLength := len(ciphertextWithMac) - ivSize - macSize
	if len(plaintext) < plaintextLength {
		return 0, errors.Errorf("plaintext buffer too small, %d < %d", len(plaintext), plaintextLength)
	}

	// extract mac
	l := len(ciphertextWithMac) - macSize
	ciphertextWithIV, mac := ciphertextWithMac[:l], ciphertextWithMac[l:]

	// verify mac
	if !poly1305Verify(ciphertextWithIV[ivSize:], ciphertextWithIV[:ivSize], &ks.MAC, mac) {
		return 0, ErrUnauthenticated
	}

	// extract iv
	iv, ciphertext := ciphertextWithIV[:ivSize], ciphertextWithIV[ivSize:]

	if len(ciphertext) != plaintextLength {
		return 0, errors.Errorf("plaintext and ciphertext lengths do not match: %d != %d", len(ciphertext), plaintextLength)
	}

	// decrypt data
	c, err := aes.NewCipher(ks.Encrypt[:])
	if err != nil {
		panic(fmt.Sprintf("unable to create cipher: %v", err))
	}

	// decrypt
	e := cipher.NewCTR(c, iv)
	plaintext = plaintext[:len(ciphertext)]
	e.XORKeyStream(plaintext, ciphertext)

	return plaintextLength, nil
}

// Return temp directory in correct directory for this backend.
func (r *SFTP) tempFile() (string, *sftp.File, error) {
	// choose random suffix
	buf := make([]byte, tempfileRandomSuffixLength)
	_, err := io.ReadFull(rand.Reader, buf)
	if err != nil {
		return "", nil, errors.Errorf("unable to read %d random bytes for tempfile name: %v",
			tempfileRandomSuffixLength, err)
	}

	// construct tempfile name
	name := Join(r.p, backend.Paths.Temp, "temp-"+hex.EncodeToString(buf))

	// create file in temp dir
	f, err := r.c.Create(name)
	if err != nil {
		return "", nil, errors.Errorf("creating tempfile %q failed: %v", name, err)
	}

	return name, f, nil
}