package restorer import ( "context" "os" "path/filepath" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/fs" "github.com/restic/restic/internal/restic" ) // Restorer is used to restore a snapshot to a directory. type Restorer struct { repo restic.Repository sn *restic.Snapshot Error func(location string, err error) error SelectFilter func(item string, dstpath string, node *restic.Node) (selectedForRestore bool, childMayBeSelected bool) } var restorerAbortOnAllErrors = func(location string, err error) error { return err } // NewRestorer creates a restorer preloaded with the content from the snapshot id. func NewRestorer(repo restic.Repository, id restic.ID) (*Restorer, error) { r := &Restorer{ repo: repo, Error: restorerAbortOnAllErrors, SelectFilter: func(string, string, *restic.Node) (bool, bool) { return true, true }, } var err error r.sn, err = restic.LoadSnapshot(context.TODO(), repo, id) if err != nil { return nil, err } return r, nil } type treeVisitor struct { enterDir func(node *restic.Node, target, location string) error visitNode func(node *restic.Node, target, location string) error leaveDir func(node *restic.Node, target, location string) error } // traverseTree traverses a tree from the repo and calls treeVisitor. // target is the path in the file system, location within the snapshot. func (res *Restorer) traverseTree(ctx context.Context, target, location string, treeID restic.ID, visitor treeVisitor) error { debug.Log("%v %v %v", target, location, treeID) tree, err := res.repo.LoadTree(ctx, treeID) if err != nil { debug.Log("error loading tree %v: %v", treeID, err) return res.Error(location, err) } for _, node := range tree.Nodes { // ensure that the node name does not contain anything that refers to a // top-level directory. nodeName := filepath.Base(filepath.Join(string(filepath.Separator), node.Name)) if nodeName != node.Name { debug.Log("node %q has invalid name %q", node.Name, nodeName) err := res.Error(location, errors.Errorf("invalid child node name %s", node.Name)) if err != nil { return err } continue } nodeTarget := filepath.Join(target, nodeName) nodeLocation := filepath.Join(location, nodeName) if target == nodeTarget || !fs.HasPathPrefix(target, nodeTarget) { debug.Log("target: %v %v", target, nodeTarget) debug.Log("node %q has invalid target path %q", node.Name, nodeTarget) err := res.Error(nodeLocation, errors.New("node has invalid path")) if err != nil { return err } continue } // sockets cannot be restored if node.Type == "socket" { continue } selectedForRestore, childMayBeSelected := res.SelectFilter(nodeLocation, nodeTarget, node) debug.Log("SelectFilter returned %v %v", selectedForRestore, childMayBeSelected) sanitizeError := func(err error) error { if err != nil { err = res.Error(nodeLocation, err) } return err } if node.Type == "dir" { if node.Subtree == nil { return errors.Errorf("Dir without subtree in tree %v", treeID.Str()) } if selectedForRestore { err = sanitizeError(visitor.enterDir(node, nodeTarget, nodeLocation)) if err != nil { return err } } if childMayBeSelected { err = sanitizeError(res.traverseTree(ctx, nodeTarget, nodeLocation, *node.Subtree, visitor)) if err != nil { return err } } if selectedForRestore { err = sanitizeError(visitor.leaveDir(node, nodeTarget, nodeLocation)) if err != nil { return err } } continue } if selectedForRestore { err = sanitizeError(visitor.visitNode(node, nodeTarget, nodeLocation)) if err != nil { return err } } } return nil } func (res *Restorer) restoreNodeTo(ctx context.Context, node *restic.Node, target, location string) error { debug.Log("restoreNode %v %v %v", node.Name, target, location) err := node.CreateAt(ctx, target, res.repo) if err != nil { debug.Log("node.CreateAt(%s) error %v", target, err) } if err == nil { err = res.restoreNodeMetadataTo(node, target, location) } return err } func (res *Restorer) restoreNodeMetadataTo(node *restic.Node, target, location string) error { debug.Log("restoreNodeMetadata %v %v %v", node.Name, target, location) err := node.RestoreMetadata(target) if err != nil { debug.Log("node.RestoreMetadata(%s) error %v", target, err) } return err } func (res *Restorer) restoreHardlinkAt(node *restic.Node, target, path, location string) error { if err := fs.Remove(path); !os.IsNotExist(err) { return errors.Wrap(err, "RemoveCreateHardlink") } err := fs.Link(target, path) if err != nil { return errors.Wrap(err, "CreateHardlink") } // TODO investigate if hardlinks have separate metadata on any supported system return res.restoreNodeMetadataTo(node, path, location) } func (res *Restorer) restoreEmptyFileAt(node *restic.Node, target, location string) error { wr, err := os.OpenFile(target, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600) if err != nil { return err } err = wr.Close() if err != nil { return err } return res.restoreNodeMetadataTo(node, target, location) } // RestoreTo creates the directories and files in the snapshot below dst. // Before an item is created, res.Filter is called. func (res *Restorer) RestoreTo(ctx context.Context, dst string) error { var err error if !filepath.IsAbs(dst) { dst, err = filepath.Abs(dst) if err != nil { return errors.Wrap(err, "Abs") } } restoreNodeMetadata := func(node *restic.Node, target, location string) error { return res.restoreNodeMetadataTo(node, target, location) } noop := func(node *restic.Node, target, location string) error { return nil } idx := restic.NewHardlinkIndex() filerestorer := newFileRestorer(dst, res.repo.Backend().Load, res.repo.Key(), res.repo.Index().Lookup) // first tree pass: create directories and collect all files to restore err = res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{ enterDir: func(node *restic.Node, target, location string) error { // create dir with default permissions // #leaveDir restores dir metadata after visiting all children return fs.MkdirAll(target, 0700) }, visitNode: func(node *restic.Node, target, location string) error { // create parent dir with default permissions // second pass #leaveDir restores dir metadata after visiting/restoring all children err := fs.MkdirAll(filepath.Dir(target), 0700) if err != nil { return err } if node.Type != "file" { return nil } if node.Size == 0 { return nil // deal with empty files later } if node.Links > 1 { if idx.Has(node.Inode, node.DeviceID) { return nil } idx.Add(node.Inode, node.DeviceID, location) } filerestorer.addFile(location, node.Content) return nil }, leaveDir: noop, }) if err != nil { return err } err = filerestorer.restoreFiles(ctx) if err != nil { return err } // second tree pass: restore special files and filesystem metadata return res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{ enterDir: noop, visitNode: func(node *restic.Node, target, location string) error { if node.Type != "file" { return res.restoreNodeTo(ctx, node, target, location) } // create empty files, but not hardlinks to empty files if node.Size == 0 && (node.Links < 2 || !idx.Has(node.Inode, node.DeviceID)) { if node.Links > 1 { idx.Add(node.Inode, node.DeviceID, location) } return res.restoreEmptyFileAt(node, target, location) } if idx.Has(node.Inode, node.DeviceID) && idx.GetFilename(node.Inode, node.DeviceID) != location { return res.restoreHardlinkAt(node, filerestorer.targetPath(idx.GetFilename(node.Inode, node.DeviceID)), target, location) } return res.restoreNodeMetadataTo(node, target, location) }, leaveDir: restoreNodeMetadata, }) } // Snapshot returns the snapshot this restorer is configured to use. func (res *Restorer) Snapshot() *restic.Snapshot { return res.sn } // VerifyFiles reads all snapshot files and verifies their contents func (res *Restorer) VerifyFiles(ctx context.Context, dst string) (int, error) { // TODO multithreaded? count := 0 err := res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{ enterDir: func(node *restic.Node, target, location string) error { return nil }, visitNode: func(node *restic.Node, target, location string) error { if node.Type != "file" { return nil } count++ stat, err := os.Stat(target) if err != nil { return err } if int64(node.Size) != stat.Size() { return errors.Errorf("Invalid file size: expected %d got %d", node.Size, stat.Size()) } file, err := os.Open(target) if err != nil { return err } offset := int64(0) for _, blobID := range node.Content { length, _ := res.repo.LookupBlobSize(blobID, restic.DataBlob) buf := make([]byte, length) // TODO do I want to reuse the buffer somehow? _, err = file.ReadAt(buf, offset) if err != nil { _ = file.Close() return err } if !blobID.Equal(restic.Hash(buf)) { _ = file.Close() return errors.Errorf("Unexpected contents starting at offset %d", offset) } offset += int64(length) } err = file.Close() if err != nil { return err } return nil }, leaveDir: func(node *restic.Node, target, location string) error { return nil }, }) return count, err }