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restic/internal/restorer/restorer.go
Alexander Neumann 44924ba043 restorer: Fix traverseTree
traverseTree() was meant to call enterDir() whenever a directory is
selected for restore, either explicitly or implicitly (=contains a file
which is to be restored). After restoring a file, leaveDir() is called
in reverse order for all intermediate directories so that the metadata
can be restored.

When a directory is selected implicitly, the metadata for it is
restored. This is different from the previous restorer behavior, which
created implicitly selected intermediate directories with permissions
0700 (only user can read/write it).

This commit changes the behavior back to the old one. Only a directory
is explicitly selected for restore, enterDir()/leaveDir() are called for
it. Otherwise, only visitNode() is called, so visitNode() needs to make
sure the parent directory exists. If the directory is explicitly
included, leaveDir() will then restore the metadata correctly.

When we decide to change the behavior (restore metadata for all
intermediate directories, even if selected implicitly), we should do
that in the selection functions, not here.

This finally resolves #1870
2018-07-21 23:24:40 +02:00

259 lines
7.5 KiB
Go

package restorer
import (
"context"
"os"
"path/filepath"
"github.com/restic/restic/internal/crypto"
"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(dir string, node *restic.Node, err error) error
SelectFilter func(item string, dstpath string, node *restic.Node) (selectedForRestore bool, childMayBeSelected bool)
}
var restorerAbortOnAllErrors = func(str string, node *restic.Node, 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, nil, 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, node, errors.New("node has invalid 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, node, 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(nodeTarget, node, 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, idx *restic.HardlinkIndex) error {
debug.Log("restoreNode %v %v %v", node.Name, target, location)
err := node.CreateAt(ctx, target, res.repo, idx)
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
}
// 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")
}
}
// make sure the target directory exists
err = fs.MkdirAll(dst, 0777) // umask takes care of dir permissions
if err != nil {
return errors.Wrap(err, "MkdirAll")
}
idx := restic.NewHardlinkIndex()
return 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
// #leaveDir restores dir metadata after visiting all children
err := fs.MkdirAll(filepath.Dir(target), 0700)
if err != nil {
return err
}
return res.restoreNodeTo(ctx, node, target, location, idx)
},
leaveDir: func(node *restic.Node, target, location string) error {
// Restore directory permissions and timestamp at the end. If we did it earlier
// - children restore could fail because of restictive directory permission
// - children restore could overwrite the timestamp of the directory they are in
return res.restoreNodeMetadataTo(node, target, location)
},
})
}
// 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())
}
offset := int64(0)
for _, blobID := range node.Content {
rd, err := os.Open(target)
if err != nil {
return err
}
blobs, _ := res.repo.Index().Lookup(blobID, restic.DataBlob)
length := blobs[0].Length - uint(crypto.Extension)
buf := make([]byte, length) // TODO do I want to reuse the buffer somehow?
_, err = rd.ReadAt(buf, offset)
if err != nil {
return err
}
if !blobID.Equal(restic.Hash(buf)) {
return errors.Errorf("Unexpected contents starting at offset %d", offset)
}
offset += int64(length)
}
return nil
},
leaveDir: func(node *restic.Node, target, location string) error { return nil },
})
return count, err
}