Add a new Samba backend

The storage url is smb://user@server[:port]/share/path.  The password can be
set in the environment variable DUPLICACY_SMB_PASSWORD for default storage or
DUPLICACY_<STORAGE_NAME>_SMB_PASSWORD.

This backend is based on https://github.com/hirochachacha/go-smb2.  The
previous samba:// backend is just an alias for the disk-based backend with
caching enabled.

src/duplicacy_sambastorage.go

@@ -0,0 +1,250 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"io"
+	"os"
+	"fmt"
+	"net"
+	"path"
+	"time"
+	"strings"
+	"syscall"
+	"math/rand"
+
+	"github.com/hirochachacha/go-smb2"
+)
+
+// SambaStorage is a local on-disk file storage implementing the Storage interface.
+type SambaStorage struct {
+	StorageBase
+
+	share           *smb2.Share
+	storageDir      string
+	numberOfThreads int
+}
+
+// CreateSambaStorage creates a file storage.
+func CreateSambaStorage(server string, port int, username string, password string, shareName string, storageDir string, threads int) (storage *SambaStorage, err error) {
+
+	connection, err := net.Dial("tcp", fmt.Sprintf("%s:%d", server, port))
+	if err != nil {
+		return nil, err
+	}
+
+	dialer := &smb2.Dialer{
+		Initiator: &smb2.NTLMInitiator{
+			User:     username,
+			Password: password,
+		},
+	}
+
+	client, err := dialer.Dial(connection)
+	if err != nil {
+		return nil, err
+	}
+
+	share, err := client.Mount(shareName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Random number fo generating the temporary chunk file suffix.
+	rand.Seed(time.Now().UnixNano())
+
+	storage = &SambaStorage{
+		share:           share,
+		numberOfThreads: threads,
+	}
+
+	exist, isDir, _, err := storage.GetFileInfo(0, storageDir)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to check the storage path %s: %v", storageDir, err)
+	}
+
+	if !exist {
+		return nil, fmt.Errorf("The storage path %s does not exist", storageDir)
+	}
+
+	if !isDir {
+		return nil, fmt.Errorf("The storage path %s is not a directory", storageDir)
+	}
+
+	storage.storageDir = storageDir
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+	return storage, nil
+}
+
+// ListFiles return the list of files and subdirectories under 'dir' (non-recursively).
+func (storage *SambaStorage) ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error) {
+
+	fullPath := path.Join(storage.storageDir, dir)
+
+	list, err := storage.share.ReadDir(fullPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil, nil
+		}
+		return nil, nil, err
+	}
+
+	for _, f := range list {
+		name := f.Name()
+		if (f.IsDir() || f.Mode() & os.ModeSymlink != 0) && name[len(name)-1] != '/' {
+			name += "/"
+		}
+		files = append(files, name)
+		sizes = append(sizes, f.Size())
+	}
+
+	return files, sizes, nil
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *SambaStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+	err = storage.share.Remove(path.Join(storage.storageDir, filePath))
+	if err == nil || os.IsNotExist(err) {
+		return nil
+	} else {
+		return err
+	}
+}
+
+// MoveFile renames the file.
+func (storage *SambaStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+	return storage.share.Rename(path.Join(storage.storageDir, from), path.Join(storage.storageDir, to))
+}
+
+// CreateDirectory creates a new directory.
+func (storage *SambaStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+	fmt.Printf("Creating directory %s\n", dir)
+	err = storage.share.Mkdir(path.Join(storage.storageDir, dir), 0744)
+	if err != nil && os.IsExist(err) {
+		return nil
+	} else {
+		return err
+	}
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *SambaStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
+	stat, err := storage.share.Stat(path.Join(storage.storageDir, filePath))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, false, 0, nil
+		} else {
+			return false, false, 0, err
+		}
+	}
+
+	return true, stat.IsDir(), stat.Size(), nil
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *SambaStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+
+	file, err := storage.share.Open(path.Join(storage.storageDir, filePath))
+
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+	if _, err = RateLimitedCopy(chunk, file, storage.DownloadRateLimit/storage.numberOfThreads); err != nil {
+		return err
+	}
+
+	return nil
+
+}
+
+// UploadFile writes 'content' to the file at 'filePath'
+func (storage *SambaStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+
+	fullPath := path.Join(storage.storageDir, filePath)
+
+	if len(strings.Split(filePath, "/")) > 2 {
+		dir := path.Dir(fullPath)
+		stat, err := storage.share.Stat(dir)
+		if err != nil {
+			if !os.IsNotExist(err) {
+				return err
+			}
+			err = storage.share.MkdirAll(dir, 0744)
+			if err != nil {
+				return err
+			}
+		} else {
+			if !stat.IsDir() && stat.Mode() & os.ModeSymlink == 0 {
+				return fmt.Errorf("The path %s is not a directory or symlink", dir)
+			}
+		}
+	}
+
+	letters := "abcdefghijklmnopqrstuvwxyz"
+	suffix := make([]byte, 8)
+	for i := range suffix {
+		suffix[i] = letters[rand.Intn(len(letters))]
+	}
+
+	temporaryFile := fullPath + "." + string(suffix) + ".tmp"
+
+	file, err := storage.share.Create(temporaryFile)
+	if err != nil {
+		return err
+	}
+
+	reader := CreateRateLimitedReader(content, storage.UploadRateLimit/storage.numberOfThreads)
+	_, err = io.Copy(file, reader)
+	if err != nil {
+		file.Close()
+		return err
+	}
+
+	if err = file.Sync(); err != nil {
+		pathErr, ok := err.(*os.PathError)
+		isNotSupported := ok && pathErr.Op == "sync" && pathErr.Err == syscall.ENOTSUP
+		if !isNotSupported {
+			_ = file.Close()
+			return err
+		}
+	}
+
+	err = file.Close()
+	if err != nil {
+		return err
+	}
+
+	err = storage.share.Rename(temporaryFile, fullPath)
+	if err != nil {
+
+		if _, e := storage.share.Stat(fullPath); e == nil {
+			storage.share.Remove(temporaryFile)
+			return nil
+		} else {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *SambaStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *SambaStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *SambaStorage) IsStrongConsistent() bool { return true }
+
+// If the storage supports fast listing of files names.
+func (storage *SambaStorage) IsFastListing() bool { return false }
+
+// Enable the test mode.
+func (storage *SambaStorage) EnableTestMode() {}