package repository import ( "context" "crypto/sha256" "fmt" "io" "os" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/fs" "github.com/restic/restic/internal/hashing" "github.com/restic/restic/internal/pack" "github.com/restic/restic/internal/restic" "github.com/restic/restic/internal/errors" ) // Repack takes a list of packs together with a list of blobs contained in // these packs. Each pack is loaded and the blobs listed in keepBlobs is saved // into a new pack. Returned is the list of obsolete packs which can then // be removed. func Repack(ctx context.Context, repo restic.Repository, packs restic.IDSet, keepBlobs restic.BlobSet, p *restic.Progress) (obsoletePacks restic.IDSet, err error) { debug.Log("repacking %d packs while keeping %d blobs", len(packs), len(keepBlobs)) for packID := range packs { // load the complete pack into a temp file h := restic.Handle{Type: restic.DataFile, Name: packID.String()} tempfile, err := fs.TempFile("", "restic-temp-repack-") if err != nil { return nil, errors.Wrap(err, "TempFile") } beRd, err := repo.Backend().Load(ctx, h, 0, 0) if err != nil { return nil, err } hrd := hashing.NewReader(beRd, sha256.New()) packLength, err := io.Copy(tempfile, hrd) if err != nil { _ = beRd.Close() return nil, errors.Wrap(err, "Copy") } if err = beRd.Close(); err != nil { return nil, errors.Wrap(err, "Close") } hash := restic.IDFromHash(hrd.Sum(nil)) debug.Log("pack %v loaded (%d bytes), hash %v", packID, packLength, hash) if !packID.Equal(hash) { return nil, errors.Errorf("hash does not match id: want %v, got %v", packID, hash) } _, err = tempfile.Seek(0, 0) if err != nil { return nil, errors.Wrap(err, "Seek") } blobs, err := pack.List(repo.Key(), tempfile, packLength) if err != nil { return nil, err } debug.Log("processing pack %v, blobs: %v", packID, len(blobs)) var buf []byte for _, entry := range blobs { h := restic.BlobHandle{ID: entry.ID, Type: entry.Type} if !keepBlobs.Has(h) { continue } debug.Log(" process blob %v", h) buf = buf[:] if uint(len(buf)) < entry.Length { buf = make([]byte, entry.Length) } buf = buf[:entry.Length] n, err := tempfile.ReadAt(buf, int64(entry.Offset)) if err != nil { return nil, errors.Wrap(err, "ReadAt") } if n != len(buf) { return nil, errors.Errorf("read blob %v from %v: not enough bytes read, want %v, got %v", h, tempfile.Name(), len(buf), n) } nonce, ciphertext := buf[:repo.Key().NonceSize()], buf[repo.Key().NonceSize():] plaintext, err := repo.Key().Open(ciphertext[:0], nonce, ciphertext, nil) if err != nil { return nil, err } id := restic.Hash(plaintext) if !id.Equal(entry.ID) { debug.Log("read blob %v/%v from %v: wrong data returned, hash is %v", h.Type, h.ID, tempfile.Name(), id) fmt.Fprintf(os.Stderr, "read blob %v from %v: wrong data returned, hash is %v", h, tempfile.Name(), id) } _, err = repo.SaveBlob(ctx, entry.Type, plaintext, entry.ID) if err != nil { return nil, err } debug.Log(" saved blob %v", entry.ID) keepBlobs.Delete(h) } if err = tempfile.Close(); err != nil { return nil, errors.Wrap(err, "Close") } if err = fs.RemoveIfExists(tempfile.Name()); err != nil { return nil, errors.Wrap(err, "Remove") } if p != nil { p.Report(restic.Stat{Blobs: 1}) } } if err := repo.Flush(ctx); err != nil { return nil, err } return packs, nil }