mirror of
https://github.com/restic/restic.git
synced 2024-12-27 18:28:30 +00:00
416 lines
12 KiB
Go
416 lines
12 KiB
Go
package restorer
|
|
|
|
import (
|
|
"context"
|
|
"os"
|
|
"path/filepath"
|
|
"sync/atomic"
|
|
|
|
"github.com/restic/restic/internal/debug"
|
|
"github.com/restic/restic/internal/errors"
|
|
"github.com/restic/restic/internal/fs"
|
|
"github.com/restic/restic/internal/restic"
|
|
|
|
"golang.org/x/sync/errgroup"
|
|
)
|
|
|
|
// 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(ctx context.Context, 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(ctx, 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) (hasRestored bool, err error) {
|
|
debug.Log("%v %v %v", target, location, treeID)
|
|
tree, err := restic.LoadTree(ctx, res.repo, treeID)
|
|
if err != nil {
|
|
debug.Log("error loading tree %v: %v", treeID, err)
|
|
return hasRestored, 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 hasRestored, 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 hasRestored, err
|
|
}
|
|
continue
|
|
}
|
|
|
|
// sockets cannot be restored
|
|
if node.Type == "socket" {
|
|
continue
|
|
}
|
|
|
|
selectedForRestore, childMayBeSelected := res.SelectFilter(nodeLocation, nodeTarget, node)
|
|
debug.Log("SelectFilter returned %v %v for %q", selectedForRestore, childMayBeSelected, nodeLocation)
|
|
|
|
if selectedForRestore {
|
|
hasRestored = true
|
|
}
|
|
|
|
sanitizeError := func(err error) error {
|
|
switch err {
|
|
case nil, context.Canceled, context.DeadlineExceeded:
|
|
// Context errors are permanent.
|
|
return err
|
|
default:
|
|
return res.Error(nodeLocation, err)
|
|
}
|
|
}
|
|
|
|
if node.Type == "dir" {
|
|
if node.Subtree == nil {
|
|
return hasRestored, errors.Errorf("Dir without subtree in tree %v", treeID.Str())
|
|
}
|
|
|
|
if selectedForRestore && visitor.enterDir != nil {
|
|
err = sanitizeError(visitor.enterDir(node, nodeTarget, nodeLocation))
|
|
if err != nil {
|
|
return hasRestored, err
|
|
}
|
|
}
|
|
|
|
// keep track of restored child status
|
|
// so metadata of the current directory are restored on leaveDir
|
|
childHasRestored := false
|
|
|
|
if childMayBeSelected {
|
|
childHasRestored, err = res.traverseTree(ctx, nodeTarget, nodeLocation, *node.Subtree, visitor)
|
|
err = sanitizeError(err)
|
|
if err != nil {
|
|
return hasRestored, err
|
|
}
|
|
// inform the parent directory to restore parent metadata on leaveDir if needed
|
|
if childHasRestored {
|
|
hasRestored = true
|
|
}
|
|
}
|
|
|
|
// metadata need to be restore when leaving the directory in both cases
|
|
// selected for restore or any child of any subtree have been restored
|
|
if (selectedForRestore || childHasRestored) && visitor.leaveDir != nil {
|
|
err = sanitizeError(visitor.leaveDir(node, nodeTarget, nodeLocation))
|
|
if err != nil {
|
|
return hasRestored, err
|
|
}
|
|
}
|
|
|
|
continue
|
|
}
|
|
|
|
if selectedForRestore {
|
|
err = sanitizeError(visitor.visitNode(node, nodeTarget, nodeLocation))
|
|
if err != nil {
|
|
return hasRestored, err
|
|
}
|
|
}
|
|
}
|
|
|
|
return hasRestored, 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")
|
|
}
|
|
}
|
|
|
|
idx := NewHardlinkIndex()
|
|
filerestorer := newFileRestorer(dst, res.repo.Backend().Load, res.repo.Key(), res.repo.Index().Lookup, res.repo.Connections())
|
|
filerestorer.Error = res.Error
|
|
|
|
debug.Log("first pass for %q", dst)
|
|
|
|
// 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 {
|
|
debug.Log("first pass, enterDir: mkdir %q, leaveDir should restore metadata", location)
|
|
// 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 {
|
|
debug.Log("first pass, visitNode: mkdir %q, leaveDir on second pass should restore metadata", location)
|
|
// 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, int64(node.Size))
|
|
|
|
return nil
|
|
},
|
|
})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
err = filerestorer.restoreFiles(ctx)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
debug.Log("second pass for %q", dst)
|
|
|
|
// second tree pass: restore special files and filesystem metadata
|
|
_, err = res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{
|
|
visitNode: func(node *restic.Node, target, location string) error {
|
|
debug.Log("second pass, visitNode: restore node %q", location)
|
|
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: res.restoreNodeMetadataTo,
|
|
})
|
|
return err
|
|
}
|
|
|
|
// Snapshot returns the snapshot this restorer is configured to use.
|
|
func (res *Restorer) Snapshot() *restic.Snapshot {
|
|
return res.sn
|
|
}
|
|
|
|
// Number of workers in VerifyFiles.
|
|
const nVerifyWorkers = 8
|
|
|
|
// VerifyFiles checks whether all regular files in the snapshot res.sn
|
|
// have been successfully written to dst. It stops when it encounters an
|
|
// error. It returns that error and the number of files it has successfully
|
|
// verified.
|
|
func (res *Restorer) VerifyFiles(ctx context.Context, dst string) (int, error) {
|
|
type mustCheck struct {
|
|
node *restic.Node
|
|
path string
|
|
}
|
|
|
|
var (
|
|
nchecked uint64
|
|
work = make(chan mustCheck, 2*nVerifyWorkers)
|
|
)
|
|
|
|
g, ctx := errgroup.WithContext(ctx)
|
|
|
|
// Traverse tree and send jobs to work.
|
|
g.Go(func() error {
|
|
defer close(work)
|
|
|
|
_, err := res.traverseTree(ctx, dst, string(filepath.Separator), *res.sn.Tree, treeVisitor{
|
|
visitNode: func(node *restic.Node, target, location string) error {
|
|
if node.Type != "file" {
|
|
return nil
|
|
}
|
|
select {
|
|
case <-ctx.Done():
|
|
return ctx.Err()
|
|
case work <- mustCheck{node, target}:
|
|
return nil
|
|
}
|
|
},
|
|
})
|
|
return err
|
|
})
|
|
|
|
for i := 0; i < nVerifyWorkers; i++ {
|
|
g.Go(func() (err error) {
|
|
var buf []byte
|
|
for job := range work {
|
|
buf, err = res.verifyFile(job.path, job.node, buf)
|
|
if err != nil {
|
|
err = res.Error(job.path, err)
|
|
}
|
|
if err != nil || ctx.Err() != nil {
|
|
break
|
|
}
|
|
atomic.AddUint64(&nchecked, 1)
|
|
}
|
|
return err
|
|
})
|
|
}
|
|
|
|
return int(nchecked), g.Wait()
|
|
}
|
|
|
|
// Verify that the file target has the contents of node.
|
|
//
|
|
// buf and the first return value are scratch space, passed around for reuse.
|
|
// Reusing buffers prevents the verifier goroutines allocating all of RAM and
|
|
// flushing the filesystem cache (at least on Linux).
|
|
func (res *Restorer) verifyFile(target string, node *restic.Node, buf []byte) ([]byte, error) {
|
|
f, err := os.Open(target)
|
|
if err != nil {
|
|
return buf, err
|
|
}
|
|
defer func() {
|
|
_ = f.Close()
|
|
}()
|
|
|
|
fi, err := f.Stat()
|
|
switch {
|
|
case err != nil:
|
|
return buf, err
|
|
case int64(node.Size) != fi.Size():
|
|
return buf, errors.Errorf("Invalid file size for %s: expected %d, got %d",
|
|
target, node.Size, fi.Size())
|
|
}
|
|
|
|
var offset int64
|
|
for _, blobID := range node.Content {
|
|
length, found := res.repo.LookupBlobSize(blobID, restic.DataBlob)
|
|
if !found {
|
|
return buf, errors.Errorf("Unable to fetch blob %s", blobID)
|
|
}
|
|
|
|
if length > uint(cap(buf)) {
|
|
buf = make([]byte, 2*length)
|
|
}
|
|
buf = buf[:length]
|
|
|
|
_, err = f.ReadAt(buf, offset)
|
|
if err != nil {
|
|
return buf, err
|
|
}
|
|
if !blobID.Equal(restic.Hash(buf)) {
|
|
return buf, errors.Errorf(
|
|
"Unexpected content in %s, starting at offset %d",
|
|
target, offset)
|
|
}
|
|
offset += int64(length)
|
|
}
|
|
|
|
return buf, nil
|
|
}
|