package repository import ( "bytes" "crypto/sha256" "encoding/json" "errors" "fmt" "io" "io/ioutil" "os" "sync" "github.com/restic/chunker" "github.com/restic/restic/backend" "github.com/restic/restic/crypto" "github.com/restic/restic/debug" "github.com/restic/restic/pack" ) // Repository is used to access a repository in a backend. type Repository struct { be backend.Backend Config Config key *crypto.Key keyName string idx *Index pm sync.Mutex packs []*pack.Packer } // New returns a new repository with backend be. func New(be backend.Backend) *Repository { return &Repository{ be: be, idx: NewIndex(), } } // Find loads the list of all blobs of type t and searches for names which start // with prefix. If none is found, nil and ErrNoIDPrefixFound is returned. If // more than one is found, nil and ErrMultipleIDMatches is returned. func (r *Repository) Find(t backend.Type, prefix string) (string, error) { return backend.Find(r.be, t, prefix) } // PrefixLength returns the number of bytes required so that all prefixes of // all IDs of type t are unique. func (r *Repository) PrefixLength(t backend.Type) (int, error) { return backend.PrefixLength(r.be, t) } // LoadAndDecrypt loads and decrypts data identified by t and id from the // backend. func (r *Repository) LoadAndDecrypt(t backend.Type, id backend.ID) ([]byte, error) { debug.Log("Repo.Load", "load %v with id %v", t, id.Str()) rd, err := r.be.Get(t, id.String()) if err != nil { debug.Log("Repo.Load", "error loading %v: %v", id.Str(), err) return nil, err } buf, err := ioutil.ReadAll(rd) if err != nil { return nil, err } err = rd.Close() if err != nil { return nil, err } // check hash if !backend.Hash(buf).Equal(id) { return nil, errors.New("invalid data returned") } // decrypt plain, err := r.Decrypt(buf) if err != nil { return nil, err } return plain, nil } // LoadBlob tries to load and decrypt content identified by t and id from a // pack from the backend, the result is stored in plaintextBuf, which must be // large enough to hold the complete blob. func (r *Repository) LoadBlob(t pack.BlobType, id backend.ID, plaintextBuf []byte) ([]byte, error) { debug.Log("Repo.LoadBlob", "load %v with id %v", t, id.Str()) // lookup pack packID, tpe, offset, length, err := r.idx.Lookup(id) if err != nil { debug.Log("Repo.LoadBlob", "id %v not found in index: %v", id.Str(), err) return nil, err } if length > uint(cap(plaintextBuf))+crypto.Extension { return nil, fmt.Errorf("buf is too small, need %d more bytes", length-uint(cap(plaintextBuf))-crypto.Extension) } if tpe != t { debug.Log("Repo.LoadBlob", "wrong type returned for %v: wanted %v, got %v", id.Str(), t, tpe) return nil, fmt.Errorf("blob has wrong type %v (wanted: %v)", tpe, t) } debug.Log("Repo.LoadBlob", "id %v found in pack %v at offset %v (length %d)", id.Str(), packID.Str(), offset, length) // load blob from pack rd, err := r.be.GetReader(backend.Data, packID.String(), offset, length) if err != nil { debug.Log("Repo.LoadBlob", "error loading pack %v for %v: %v", packID.Str(), id.Str(), err) return nil, err } // make buffer that is large enough for the complete blob ciphertextBuf := make([]byte, length) _, err = io.ReadFull(rd, ciphertextBuf) if err != nil { return nil, err } err = rd.Close() if err != nil { return nil, err } // decrypt plaintextBuf, err = r.decryptTo(plaintextBuf, ciphertextBuf) if err != nil { return nil, err } // check hash if !backend.Hash(plaintextBuf).Equal(id) { return nil, errors.New("invalid data returned") } return plaintextBuf, nil } // LoadJSONUnpacked decrypts the data and afterwards calls json.Unmarshal on // the item. func (r *Repository) LoadJSONUnpacked(t backend.Type, id backend.ID, item interface{}) error { // load blob from backend rd, err := r.be.Get(t, id.String()) if err != nil { return err } defer rd.Close() // decrypt decryptRd, err := crypto.DecryptFrom(r.key, rd) defer decryptRd.Close() if err != nil { return err } // decode decoder := json.NewDecoder(decryptRd) err = decoder.Decode(item) if err != nil { return err } return nil } // LoadJSONPack calls LoadBlob() to load a blob from the backend, decrypt the // data and afterwards call json.Unmarshal on the item. func (r *Repository) LoadJSONPack(t pack.BlobType, id backend.ID, item interface{}) error { // lookup pack packID, _, offset, length, err := r.idx.Lookup(id) if err != nil { return err } // load blob from pack rd, err := r.be.GetReader(backend.Data, packID.String(), offset, length) if err != nil { return err } defer rd.Close() // decrypt decryptRd, err := crypto.DecryptFrom(r.key, rd) defer decryptRd.Close() if err != nil { return err } // decode decoder := json.NewDecoder(decryptRd) err = decoder.Decode(item) if err != nil { return err } return nil } // LookupBlobSize returns the size of blob id. func (r *Repository) LookupBlobSize(id backend.ID) (uint, error) { return r.Index().LookupSize(id) } const minPackSize = 4 * chunker.MiB const maxPackSize = 16 * chunker.MiB const maxPackers = 200 // findPacker returns a packer for a new blob of size bytes. Either a new one is // created or one is returned that already has some blobs. func (r *Repository) findPacker(size uint) (*pack.Packer, error) { r.pm.Lock() defer r.pm.Unlock() // search for a suitable packer if len(r.packs) > 0 { debug.Log("Repo.findPacker", "searching packer for %d bytes\n", size) for i, p := range r.packs { if p.Size()+size < maxPackSize { debug.Log("Repo.findPacker", "found packer %v", p) // remove from list r.packs = append(r.packs[:i], r.packs[i+1:]...) return p, nil } } } // no suitable packer found, return new blob, err := r.be.Create() if err != nil { return nil, err } debug.Log("Repo.findPacker", "create new pack %p", blob) return pack.NewPacker(r.key, blob), nil } // insertPacker appends p to s.packs. func (r *Repository) insertPacker(p *pack.Packer) { r.pm.Lock() defer r.pm.Unlock() r.packs = append(r.packs, p) debug.Log("Repo.insertPacker", "%d packers\n", len(r.packs)) } // savePacker stores p in the backend. func (r *Repository) savePacker(p *pack.Packer) error { debug.Log("Repo.savePacker", "save packer with %d blobs\n", p.Count()) _, err := p.Finalize() if err != nil { return err } // move file to the final location sid := p.ID() err = p.Writer().(backend.Blob).Finalize(backend.Data, sid.String()) if err != nil { debug.Log("Repo.savePacker", "blob Finalize() error: %v", err) return err } debug.Log("Repo.savePacker", "saved as %v", sid.Str()) // update blobs in the index for _, b := range p.Blobs() { debug.Log("Repo.savePacker", " updating blob %v to pack %v", b.ID.Str(), sid.Str()) r.idx.Store(b.Type, b.ID, &sid, b.Offset, uint(b.Length)) } return nil } // countPacker returns the number of open (unfinished) packers. func (r *Repository) countPacker() int { r.pm.Lock() defer r.pm.Unlock() return len(r.packs) } // SaveAndEncrypt encrypts data and stores it to the backend as type t. If data is small // enough, it will be packed together with other small blobs. func (r *Repository) SaveAndEncrypt(t pack.BlobType, data []byte, id *backend.ID) (backend.ID, error) { if id == nil { // compute plaintext hash hashedID := backend.Hash(data) id = &hashedID } debug.Log("Repo.Save", "save id %v (%v, %d bytes)", id.Str(), t, len(data)) // get buf from the pool ciphertext := getBuf() defer freeBuf(ciphertext) // encrypt blob ciphertext, err := r.Encrypt(ciphertext, data) if err != nil { return backend.ID{}, err } // add this id to the index, although we don't know yet in which pack it // will be saved; the entry will be updated when the pack is written. // Note: the current id needs to be added to the index before searching // for a suitable packer: There's a little chance that more than one // goroutine handles the same blob concurrently. Due to idx.StoreInProgress // locking the index and raising an error if a matching index entry // already exists, updating the index first ensures that only one of // those goroutines will continue. See issue restic#292. debug.Log("Repo.Save", "saving stub for %v (%v) in index", id.Str, t) err = r.idx.StoreInProgress(t, *id) if err != nil { debug.Log("Repo.Save", "another goroutine is already working on %v (%v) does already exist", id.Str, t) return *id, nil } // find suitable packer and add blob packer, err := r.findPacker(uint(len(ciphertext))) if err != nil { r.idx.Remove(*id) return backend.ID{}, err } // save ciphertext packer.Add(t, *id, bytes.NewReader(ciphertext)) // if the pack is not full enough and there are less than maxPackers // packers, put back to the list if packer.Size() < minPackSize && r.countPacker() < maxPackers { debug.Log("Repo.Save", "pack is not full enough (%d bytes)", packer.Size()) r.insertPacker(packer) return *id, nil } // else write the pack to the backend return *id, r.savePacker(packer) } // SaveFrom encrypts data read from rd and stores it in a pack in the backend as type t. func (r *Repository) SaveFrom(t pack.BlobType, id *backend.ID, length uint, rd io.Reader) error { debug.Log("Repo.SaveFrom", "save id %v (%v, %d bytes)", id.Str(), t, length) if id == nil { return errors.New("id is nil") } buf, err := ioutil.ReadAll(rd) if err != nil { return err } _, err = r.SaveAndEncrypt(t, buf, id) if err != nil { return err } return nil } // SaveJSON serialises item as JSON and encrypts and saves it in a pack in the // backend as type t. func (r *Repository) SaveJSON(t pack.BlobType, item interface{}) (backend.ID, error) { debug.Log("Repo.SaveJSON", "save %v blob", t) buf := getBuf()[:0] defer freeBuf(buf) wr := bytes.NewBuffer(buf) enc := json.NewEncoder(wr) err := enc.Encode(item) if err != nil { return backend.ID{}, fmt.Errorf("json.Encode: %v", err) } buf = wr.Bytes() return r.SaveAndEncrypt(t, buf, nil) } // SaveJSONUnpacked serialises item as JSON and encrypts and saves it in the // backend as type t, without a pack. It returns the storage hash. func (r *Repository) SaveJSONUnpacked(t backend.Type, item interface{}) (backend.ID, error) { // create file blob, err := r.be.Create() if err != nil { return backend.ID{}, err } debug.Log("Repo.SaveJSONUnpacked", "create new blob %v", t) // hash hw := backend.NewHashingWriter(blob, sha256.New()) // encrypt blob ewr := crypto.EncryptTo(r.key, hw) enc := json.NewEncoder(ewr) err = enc.Encode(item) if err != nil { return backend.ID{}, fmt.Errorf("json.Encode: %v", err) } err = ewr.Close() if err != nil { return backend.ID{}, err } // finalize blob in the backend hash := hw.Sum(nil) sid := backend.ID{} copy(sid[:], hash) err = blob.Finalize(t, sid.String()) if err != nil { debug.Log("Repo.SaveJSONUnpacked", "error saving blob %v as %v: %v", t, sid, err) return backend.ID{}, err } debug.Log("Repo.SaveJSONUnpacked", "new blob %v saved as %v", t, sid) return sid, nil } // Flush saves all remaining packs. func (r *Repository) Flush() error { r.pm.Lock() defer r.pm.Unlock() debug.Log("Repo.Flush", "manually flushing %d packs", len(r.packs)) for _, p := range r.packs { err := r.savePacker(p) if err != nil { return err } } r.packs = r.packs[:0] return nil } // Backend returns the backend for the repository. func (r *Repository) Backend() backend.Backend { return r.be } // Index returns the currently loaded Index. func (r *Repository) Index() *Index { return r.idx } // SetIndex instructs the repository to use the given index. func (r *Repository) SetIndex(i *Index) { r.idx = i } // BlobWriter encrypts and saves the data written to it in a backend. After // Close() was called, ID() returns the backend.ID. type BlobWriter struct { id backend.ID blob backend.Blob hw *backend.HashingWriter ewr io.WriteCloser t backend.Type closed bool } // CreateEncryptedBlob returns a BlobWriter that encrypts and saves the data // written to it in the backend. After Close() was called, ID() returns the // backend.ID. func (r *Repository) CreateEncryptedBlob(t backend.Type) (*BlobWriter, error) { blob, err := r.be.Create() if err != nil { return nil, err } // hash hw := backend.NewHashingWriter(blob, sha256.New()) // encrypt blob ewr := crypto.EncryptTo(r.key, hw) return &BlobWriter{t: t, blob: blob, hw: hw, ewr: ewr}, nil } func (bw *BlobWriter) Write(buf []byte) (int, error) { return bw.ewr.Write(buf) } // Close finalizes the blob in the backend, afterwards ID() can be used to retrieve the ID. func (bw *BlobWriter) Close() error { if bw.closed { return errors.New("BlobWriter already closed") } bw.closed = true err := bw.ewr.Close() if err != nil { return err } copy(bw.id[:], bw.hw.Sum(nil)) return bw.blob.Finalize(bw.t, bw.id.String()) } // ID returns the Id the blob has been written to after Close() was called. func (bw *BlobWriter) ID() backend.ID { return bw.id } // SaveIndex saves all new packs in the index in the backend, returned is the // storage ID. func (r *Repository) SaveIndex() (backend.ID, error) { debug.Log("Repo.SaveIndex", "Saving index") blob, err := r.CreateEncryptedBlob(backend.Index) if err != nil { return backend.ID{}, err } err = r.idx.Encode(blob) if err != nil { return backend.ID{}, err } err = blob.Close() if err != nil { return backend.ID{}, err } sid := blob.ID() debug.Log("Repo.SaveIndex", "Saved index as %v", sid.Str()) return sid, nil } const loadIndexParallelism = 20 // LoadIndex loads all index files from the backend in parallel and merges them // with the current index. The first error that occurred is returned. func (r *Repository) LoadIndex() error { debug.Log("Repo.LoadIndex", "Loading index") errCh := make(chan error, 1) indexes := make(chan *Index) worker := func(id string, done <-chan struct{}) error { idx, err := LoadIndex(r, id) if err != nil { return err } select { case indexes <- idx: case <-done: } return nil } go func() { defer close(indexes) errCh <- FilesInParallel(r.be, backend.Index, loadIndexParallelism, worker) }() for idx := range indexes { r.idx.Merge(idx) } if err := <-errCh; err != nil { return err } return nil } // LoadIndex loads the index id from backend and returns it. func LoadIndex(repo *Repository, id string) (*Index, error) { idx, err := loadIndex(repo, id, false) if err == nil { return idx, nil } if err == ErrOldIndexFormat { fmt.Fprintf(os.Stderr, "index %v has old format\n", id) return loadIndex(repo, id, true) } return nil, err } // decryptReadCloser couples an underlying reader with a DecryptReader and // implements io.ReadCloser. On Close(), both readers are closed. type decryptReadCloser struct { r io.ReadCloser dr io.ReadCloser } func newDecryptReadCloser(key *crypto.Key, rd io.ReadCloser) (io.ReadCloser, error) { dr, err := crypto.DecryptFrom(key, rd) if err != nil { return nil, err } return &decryptReadCloser{r: rd, dr: dr}, nil } func (dr *decryptReadCloser) Read(buf []byte) (int, error) { return dr.dr.Read(buf) } func (dr *decryptReadCloser) Close() error { err := dr.dr.Close() if err != nil { return err } return dr.r.Close() } // GetDecryptReader opens the file id stored in the backend and returns a // reader that yields the decrypted content. The reader must be closed. func (r *Repository) GetDecryptReader(t backend.Type, id string) (io.ReadCloser, error) { rd, err := r.be.Get(t, id) if err != nil { return nil, err } return newDecryptReadCloser(r.key, rd) } func loadIndex(repo *Repository, id string, oldFormat bool) (*Index, error) { debug.Log("loadIndex", "Loading index %v", id[:8]) rd, err := repo.GetDecryptReader(backend.Index, id) if err != nil { return nil, err } defer rd.Close() var idx *Index if !oldFormat { idx, _, err = DecodeIndex(rd) } else { idx, _, err = DecodeOldIndex(rd) } if err != nil { debug.Log("loadIndex", "error while decoding index %v: %v", id, err) return nil, err } return idx, nil } // SearchKey finds a key with the supplied password, afterwards the config is // read and parsed. func (r *Repository) SearchKey(password string) error { key, err := SearchKey(r, password) if err != nil { return err } r.key = key.master r.keyName = key.Name() r.Config, err = LoadConfig(r) return err } // Init creates a new master key with the supplied password, initializes and // saves the repository config. func (r *Repository) Init(password string) error { has, err := r.be.Test(backend.Config, "") if err != nil { return err } if has { return errors.New("repository master key and config already initialized") } key, err := createMasterKey(r, password) if err != nil { return err } r.key = key.master r.keyName = key.Name() r.Config, err = CreateConfig(r) return err } // Decrypt authenticates and decrypts ciphertext and returns the plaintext. func (r *Repository) Decrypt(ciphertext []byte) ([]byte, error) { return r.decryptTo(nil, ciphertext) } // decrypt authenticates and decrypts ciphertext and stores the result in // plaintext. func (r *Repository) decryptTo(plaintext, ciphertext []byte) ([]byte, error) { if r.key == nil { return nil, errors.New("key for repository not set") } return crypto.Decrypt(r.key, nil, ciphertext) } // Encrypt encrypts and authenticates the plaintext and saves the result in // ciphertext. func (r *Repository) Encrypt(ciphertext, plaintext []byte) ([]byte, error) { if r.key == nil { return nil, errors.New("key for repository not set") } return crypto.Encrypt(r.key, ciphertext, plaintext) } // Key returns the current master key. func (r *Repository) Key() *crypto.Key { return r.key } // KeyName returns the name of the current key in the backend. func (r *Repository) KeyName() string { return r.keyName } // Count returns the number of blobs of a given type in the backend. func (r *Repository) Count(t backend.Type) (n uint) { for _ = range r.be.List(t, nil) { n++ } return } func (r *Repository) list(t backend.Type, done <-chan struct{}, out chan<- backend.ID) { defer close(out) in := r.be.List(t, done) var ( // disable sending on the outCh until we received a job outCh chan<- backend.ID // enable receiving from in inCh = in id backend.ID err error ) for { select { case <-done: return case strID, ok := <-inCh: if !ok { // input channel closed, we're done return } id, err = backend.ParseID(strID) if err != nil { // ignore invalid IDs continue } inCh = nil outCh = out case outCh <- id: outCh = nil inCh = in } } } // List returns a channel that yields all IDs of type t in the backend. func (r *Repository) List(t backend.Type, done <-chan struct{}) <-chan backend.ID { outCh := make(chan backend.ID) go r.list(t, done, outCh) return outCh } // Delete calls backend.Delete() if implemented, and returns an error // otherwise. func (r *Repository) Delete() error { if b, ok := r.be.(backend.Deleter); ok { return b.Delete() } return errors.New("Delete() called for backend that does not implement this method") } // Close closes the repository by closing the backend. func (r *Repository) Close() error { return r.be.Close() }