package checker import ( "context" "fmt" "io" "os" "sync" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/pack" "github.com/restic/restic/internal/repository" "github.com/restic/restic/internal/restic" "golang.org/x/sync/errgroup" ) // Checker runs various checks on a repository. It is advisable to create an // exclusive Lock in the repository before running any checks. // // A Checker only tests for internal errors within the data structures of the // repository (e.g. missing blobs), and needs a valid Repository to work on. type Checker struct { packs restic.IDSet blobRefs struct { sync.Mutex // see flags below M map[restic.BlobHandle]blobStatus } masterIndex *repository.MasterIndex repo restic.Repository } type blobStatus uint8 const ( blobStatusExists blobStatus = 1 << iota blobStatusReferenced ) // New returns a new checker which runs on repo. func New(repo restic.Repository) *Checker { c := &Checker{ packs: restic.NewIDSet(), masterIndex: repository.NewMasterIndex(), repo: repo, } c.blobRefs.M = make(map[restic.BlobHandle]blobStatus) return c } const defaultParallelism = 5 // ErrDuplicatePacks is returned when a pack is found in more than one index. type ErrDuplicatePacks struct { PackID restic.ID Indexes restic.IDSet } func (e ErrDuplicatePacks) Error() string { return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID.Str(), e.Indexes) } // ErrOldIndexFormat is returned when an index with the old format is // found. type ErrOldIndexFormat struct { restic.ID } func (err ErrOldIndexFormat) Error() string { return fmt.Sprintf("index %v has old format", err.ID.Str()) } // LoadIndex loads all index files. func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) { debug.Log("Start") // track spawned goroutines using wg, create a new context which is // cancelled as soon as an error occurs. wg, ctx := errgroup.WithContext(ctx) type FileInfo struct { restic.ID Size int64 } type Result struct { *repository.Index restic.ID Err error } ch := make(chan FileInfo) resultCh := make(chan Result) // send list of index files through ch, which is closed afterwards wg.Go(func() error { defer close(ch) return c.repo.List(ctx, restic.IndexFile, func(id restic.ID, size int64) error { select { case <-ctx.Done(): return nil case ch <- FileInfo{id, size}: } return nil }) }) // a worker receives an index ID from ch, loads the index, and sends it to indexCh worker := func() error { var buf []byte for fi := range ch { debug.Log("worker got file %v", fi.ID.Str()) var err error var idx *repository.Index idx, buf, err = repository.LoadIndexWithDecoder(ctx, c.repo, buf[:0], fi.ID, repository.DecodeIndex) if errors.Cause(err) == repository.ErrOldIndexFormat { debug.Log("index %v has old format", fi.ID.Str()) hints = append(hints, ErrOldIndexFormat{fi.ID}) idx, buf, err = repository.LoadIndexWithDecoder(ctx, c.repo, buf[:0], fi.ID, repository.DecodeOldIndex) } err = errors.Wrapf(err, "error loading index %v", fi.ID.Str()) select { case resultCh <- Result{idx, fi.ID, err}: case <-ctx.Done(): } } return nil } // final closes indexCh after all workers have terminated final := func() { close(resultCh) } // run workers on ch wg.Go(func() error { return repository.RunWorkers(ctx, defaultParallelism, worker, final) }) // receive decoded indexes packToIndex := make(map[restic.ID]restic.IDSet) wg.Go(func() error { for res := range resultCh { debug.Log("process index %v, err %v", res.ID, res.Err) if res.Err != nil { errs = append(errs, res.Err) continue } c.masterIndex.Insert(res.Index) debug.Log("process blobs") cnt := 0 for blob := range res.Index.Each(ctx) { c.packs.Insert(blob.PackID) h := restic.BlobHandle{ID: blob.ID, Type: blob.Type} c.blobRefs.M[h] = blobStatusExists cnt++ if _, ok := packToIndex[blob.PackID]; !ok { packToIndex[blob.PackID] = restic.NewIDSet() } packToIndex[blob.PackID].Insert(res.ID) } debug.Log("%d blobs processed", cnt) } return nil }) err := wg.Wait() if err != nil { errs = append(errs, err) } debug.Log("checking for duplicate packs") for packID := range c.packs { debug.Log(" check pack %v: contained in %d indexes", packID, len(packToIndex[packID])) if len(packToIndex[packID]) > 1 { hints = append(hints, ErrDuplicatePacks{ PackID: packID, Indexes: packToIndex[packID], }) } } c.masterIndex.MergeFinalIndexes() err = c.repo.SetIndex(c.masterIndex) if err != nil { debug.Log("SetIndex returned error: %v", err) errs = append(errs, err) } return hints, errs } // PackError describes an error with a specific pack. type PackError struct { ID restic.ID Orphaned bool Err error } func (e PackError) Error() string { return "pack " + e.ID.Str() + ": " + e.Err.Error() } // IsOrphanedPack returns true if the error describes a pack which is not // contained in any index. func IsOrphanedPack(err error) bool { if e, ok := errors.Cause(err).(PackError); ok && e.Orphaned { return true } return false } // Packs checks that all packs referenced in the index are still available and // there are no packs that aren't in an index. errChan is closed after all // packs have been checked. func (c *Checker) Packs(ctx context.Context, errChan chan<- error) { defer close(errChan) debug.Log("checking for %d packs", len(c.packs)) debug.Log("listing repository packs") repoPacks := restic.NewIDSet() err := c.repo.List(ctx, restic.PackFile, func(id restic.ID, size int64) error { repoPacks.Insert(id) return nil }) if err != nil { errChan <- err } // orphaned: present in the repo but not in c.packs for orphanID := range repoPacks.Sub(c.packs) { select { case <-ctx.Done(): return case errChan <- PackError{ID: orphanID, Orphaned: true, Err: errors.New("not referenced in any index")}: } } // missing: present in c.packs but not in the repo for missingID := range c.packs.Sub(repoPacks) { select { case <-ctx.Done(): return case errChan <- PackError{ID: missingID, Err: errors.New("does not exist")}: } } } // Error is an error that occurred while checking a repository. type Error struct { TreeID restic.ID BlobID restic.ID Err error } func (e Error) Error() string { if !e.BlobID.IsNull() && !e.TreeID.IsNull() { msg := "tree " + e.TreeID.Str() msg += ", blob " + e.BlobID.Str() msg += ": " + e.Err.Error() return msg } if !e.TreeID.IsNull() { return "tree " + e.TreeID.Str() + ": " + e.Err.Error() } return e.Err.Error() } func loadTreeFromSnapshot(ctx context.Context, repo restic.Repository, id restic.ID) (restic.ID, error) { sn, err := restic.LoadSnapshot(ctx, repo, id) if err != nil { debug.Log("error loading snapshot %v: %v", id, err) return restic.ID{}, err } if sn.Tree == nil { debug.Log("snapshot %v has no tree", id) return restic.ID{}, errors.Errorf("snapshot %v has no tree", id) } return *sn.Tree, nil } // loadSnapshotTreeIDs loads all snapshots from backend and returns the tree IDs. func loadSnapshotTreeIDs(ctx context.Context, repo restic.Repository) (restic.IDs, []error) { var trees struct { IDs restic.IDs sync.Mutex } var errs struct { errs []error sync.Mutex } // track spawned goroutines using wg, create a new context which is // cancelled as soon as an error occurs. wg, ctx := errgroup.WithContext(ctx) ch := make(chan restic.ID) // send list of index files through ch, which is closed afterwards wg.Go(func() error { defer close(ch) return repo.List(ctx, restic.SnapshotFile, func(id restic.ID, size int64) error { select { case <-ctx.Done(): return nil case ch <- id: } return nil }) }) // a worker receives an index ID from ch, loads the snapshot and the tree, // and adds the result to errs and trees. worker := func() error { for id := range ch { debug.Log("load snapshot %v", id) treeID, err := loadTreeFromSnapshot(ctx, repo, id) if err != nil { errs.Lock() errs.errs = append(errs.errs, err) errs.Unlock() continue } debug.Log("snapshot %v has tree %v", id, treeID) trees.Lock() trees.IDs = append(trees.IDs, treeID) trees.Unlock() } return nil } for i := 0; i < defaultParallelism; i++ { wg.Go(worker) } err := wg.Wait() if err != nil { errs.errs = append(errs.errs, err) } return trees.IDs, errs.errs } // TreeError collects several errors that occurred while processing a tree. type TreeError struct { ID restic.ID Errors []error } func (e TreeError) Error() string { return fmt.Sprintf("tree %v: %v", e.ID.Str(), e.Errors) } type treeJob struct { restic.ID error *restic.Tree } // loadTreeWorker loads trees from repo and sends them to out. func loadTreeWorker(ctx context.Context, repo restic.Repository, in <-chan restic.ID, out chan<- treeJob, wg *sync.WaitGroup) { defer func() { debug.Log("exiting") wg.Done() }() var ( inCh = in outCh = out job treeJob ) outCh = nil for { select { case <-ctx.Done(): return case treeID, ok := <-inCh: if !ok { return } debug.Log("load tree %v", treeID) tree, err := repo.LoadTree(ctx, treeID) debug.Log("load tree %v (%v) returned err: %v", tree, treeID, err) job = treeJob{ID: treeID, error: err, Tree: tree} outCh = out inCh = nil case outCh <- job: debug.Log("sent tree %v", job.ID) outCh = nil inCh = in } } } // checkTreeWorker checks the trees received and sends out errors to errChan. func (c *Checker) checkTreeWorker(ctx context.Context, in <-chan treeJob, out chan<- error, wg *sync.WaitGroup) { defer func() { debug.Log("exiting") wg.Done() }() var ( inCh = in outCh = out treeError TreeError ) outCh = nil for { select { case <-ctx.Done(): debug.Log("done channel closed, exiting") return case job, ok := <-inCh: if !ok { debug.Log("input channel closed, exiting") return } debug.Log("check tree %v (tree %v, err %v)", job.ID, job.Tree, job.error) var errs []error if job.error != nil { errs = append(errs, job.error) } else { errs = c.checkTree(job.ID, job.Tree) } if len(errs) > 0 { debug.Log("checked tree %v: %v errors", job.ID, len(errs)) treeError = TreeError{ID: job.ID, Errors: errs} outCh = out inCh = nil } case outCh <- treeError: debug.Log("tree %v: sent %d errors", treeError.ID, len(treeError.Errors)) outCh = nil inCh = in } } } func (c *Checker) filterTrees(ctx context.Context, backlog restic.IDs, loaderChan chan<- restic.ID, in <-chan treeJob, out chan<- treeJob) { defer func() { debug.Log("closing output channels") close(loaderChan) close(out) }() var ( inCh = in outCh = out loadCh = loaderChan job treeJob nextTreeID restic.ID outstandingLoadTreeJobs = 0 ) outCh = nil loadCh = nil for { if loadCh == nil && len(backlog) > 0 { // process last added ids first, that is traverse the tree in depth-first order ln := len(backlog) - 1 nextTreeID, backlog = backlog[ln], backlog[:ln] // use a separate flag for processed trees to ensure that check still processes trees // even when a file references a tree blob c.blobRefs.Lock() h := restic.BlobHandle{ID: nextTreeID, Type: restic.TreeBlob} status := c.blobRefs.M[h] c.blobRefs.Unlock() if (status & blobStatusReferenced) != 0 { continue } loadCh = loaderChan } if loadCh == nil && outCh == nil && outstandingLoadTreeJobs == 0 { debug.Log("backlog is empty, all channels nil, exiting") return } select { case <-ctx.Done(): return case loadCh <- nextTreeID: outstandingLoadTreeJobs++ loadCh = nil c.blobRefs.Lock() h := restic.BlobHandle{ID: nextTreeID, Type: restic.TreeBlob} c.blobRefs.M[h] |= blobStatusReferenced c.blobRefs.Unlock() case j, ok := <-inCh: if !ok { debug.Log("input channel closed") inCh = nil in = nil continue } outstandingLoadTreeJobs-- debug.Log("input job tree %v", j.ID) if j.error != nil { debug.Log("received job with error: %v (tree %v, ID %v)", j.error, j.Tree, j.ID) } else if j.Tree == nil { debug.Log("received job with nil tree pointer: %v (ID %v)", j.error, j.ID) // send a new job with the new error instead of the old one j = treeJob{ID: j.ID, error: errors.New("tree is nil and error is nil")} } else { subtrees := j.Tree.Subtrees() debug.Log("subtrees for tree %v: %v", j.ID, subtrees) // iterate backwards over subtree to compensate backwards traversal order of nextTreeID selection for i := len(subtrees) - 1; i >= 0; i-- { id := subtrees[i] if id.IsNull() { // We do not need to raise this error here, it is // checked when the tree is checked. Just make sure // that we do not add any null IDs to the backlog. debug.Log("tree %v has nil subtree", j.ID) continue } backlog = append(backlog, id) } } job = j outCh = out inCh = nil case outCh <- job: debug.Log("tree sent to check: %v", job.ID) outCh = nil inCh = in } } } // Structure checks that for all snapshots all referenced data blobs and // subtrees are available in the index. errChan is closed after all trees have // been traversed. func (c *Checker) Structure(ctx context.Context, errChan chan<- error) { defer close(errChan) trees, errs := loadSnapshotTreeIDs(ctx, c.repo) debug.Log("need to check %d trees from snapshots, %d errs returned", len(trees), len(errs)) for _, err := range errs { select { case <-ctx.Done(): return case errChan <- err: } } treeIDChan := make(chan restic.ID) treeJobChan1 := make(chan treeJob) treeJobChan2 := make(chan treeJob) var wg sync.WaitGroup for i := 0; i < defaultParallelism; i++ { wg.Add(2) go loadTreeWorker(ctx, c.repo, treeIDChan, treeJobChan1, &wg) go c.checkTreeWorker(ctx, treeJobChan2, errChan, &wg) } c.filterTrees(ctx, trees, treeIDChan, treeJobChan1, treeJobChan2) wg.Wait() } func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) { debug.Log("checking tree %v", id) 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)}) } var size uint64 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) blobSize, found := c.repo.LookupBlobSize(blobID, restic.DataBlob) if !found { errs = append(errs, Error{TreeID: id, Err: errors.Errorf("file %q blob %d size could not be found", node.Name, b)}) } size += uint64(blobSize) } 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() h := restic.BlobHandle{ID: blobID, Type: restic.DataBlob} if (c.blobRefs.M[h] & blobStatusExists) == 0 { debug.Log("tree %v references blob %v which isn't contained in index", id, blobID) errs = append(errs, Error{TreeID: id, BlobID: blobID, Err: errors.New("not found in index")}) } c.blobRefs.M[h] |= blobStatusReferenced debug.Log("blob %v is referenced", blobID) c.blobRefs.Unlock() } return errs } // UnusedBlobs returns all blobs that have never been referenced. func (c *Checker) UnusedBlobs() (blobs restic.BlobHandles) { c.blobRefs.Lock() defer c.blobRefs.Unlock() debug.Log("checking %d blobs", len(c.blobRefs.M)) for id, flags := range c.blobRefs.M { if (flags & blobStatusReferenced) == 0 { debug.Log("blob %v not referenced", id) blobs = append(blobs, id) } } return blobs } // CountPacks returns the number of packs in the repository. func (c *Checker) CountPacks() uint64 { return uint64(len(c.packs)) } // GetPacks returns IDSet of packs in the repository func (c *Checker) GetPacks() restic.IDSet { return c.packs } // checkPack reads a pack and checks the integrity of all blobs. func checkPack(ctx context.Context, r restic.Repository, id restic.ID) error { debug.Log("checking pack %v", id) h := restic.Handle{Type: restic.PackFile, Name: id.String()} packfile, hash, size, err := repository.DownloadAndHash(ctx, r.Backend(), h) if err != nil { return errors.Wrap(err, "checkPack") } defer func() { _ = packfile.Close() _ = os.Remove(packfile.Name()) }() debug.Log("hash for pack %v is %v", id, hash) if !hash.Equal(id) { debug.Log("Pack ID does not match, want %v, got %v", id, hash) return errors.Errorf("Pack ID does not match, want %v, got %v", id.Str(), hash.Str()) } blobs, err := pack.List(r.Key(), packfile, size) if err != nil { return err } var errs []error var buf []byte for i, blob := range blobs { debug.Log(" check blob %d: %v", i, blob) buf = buf[:cap(buf)] if uint(len(buf)) < blob.Length { buf = make([]byte, blob.Length) } buf = buf[:blob.Length] _, err := packfile.Seek(int64(blob.Offset), 0) if err != nil { return errors.Errorf("Seek(%v): %v", blob.Offset, err) } _, err = io.ReadFull(packfile, buf) if err != nil { debug.Log(" error loading blob %v: %v", blob.ID, err) errs = append(errs, errors.Errorf("blob %v: %v", i, err)) continue } nonce, ciphertext := buf[:r.Key().NonceSize()], buf[r.Key().NonceSize():] plaintext, err := r.Key().Open(ciphertext[:0], nonce, ciphertext, nil) if err != nil { debug.Log(" error decrypting blob %v: %v", blob.ID, err) errs = append(errs, errors.Errorf("blob %v: %v", i, err)) continue } hash := restic.Hash(plaintext) if !hash.Equal(blob.ID) { debug.Log(" Blob ID does not match, want %v, got %v", blob.ID, hash) 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 } // ReadData loads all data from the repository and checks the integrity. func (c *Checker) ReadData(ctx context.Context, p *restic.Progress, errChan chan<- error) { c.ReadPacks(ctx, c.packs, p, errChan) } // ReadPacks loads data from specified packs and checks the integrity. func (c *Checker) ReadPacks(ctx context.Context, packs restic.IDSet, p *restic.Progress, errChan chan<- error) { defer close(errChan) p.Start() defer p.Done() g, ctx := errgroup.WithContext(ctx) ch := make(chan restic.ID) // run workers for i := 0; i < defaultParallelism; i++ { g.Go(func() error { for { var id restic.ID var ok bool select { case <-ctx.Done(): return nil case id, ok = <-ch: if !ok { return nil } } err := checkPack(ctx, c.repo, id) p.Report(restic.Stat{Blobs: 1}) if err == nil { continue } select { case <-ctx.Done(): return nil case errChan <- err: } } }) } // push packs to ch for pack := range packs { select { case ch <- pack: case <-ctx.Done(): } } close(ch) err := g.Wait() if err != nil { select { case <-ctx.Done(): return case errChan <- err: } } }