restic/repository/repository.go
2015-10-14 20:50:54 +02:00

801 lines
19 KiB
Go

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 *MasterIndex
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: NewMasterIndex(),
}
}
// 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.idx.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 for %d bytes", blob, size)
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.Current().Store(b.Type, b.ID, &sid, b.Offset, uint(b.Length))
r.idx.RemoveFromInFlight(b.ID)
}
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 list of in-flight chunk ids.
debug.Log("Repo.Save", "add %v to list of in-flight IDs", id.Str())
err = r.idx.AddInFlight(*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.RemoveFromInFlight(*id)
return backend.ID{}, err
}
// save ciphertext
_, err = packer.Add(t, *id, bytes.NewReader(ciphertext))
if err != nil {
return backend.ID{}, err
}
// 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 used MasterIndex.
func (r *Repository) Index() *MasterIndex {
return r.idx
}
// SetIndex instructs the repository to use the given index.
func (r *Repository) SetIndex(i *MasterIndex) {
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 indexes in the backend.
func (r *Repository) saveIndex(indexes ...*Index) error {
for i, idx := range indexes {
debug.Log("Repo.SaveIndex", "Saving index %d", i)
blob, err := r.CreateEncryptedBlob(backend.Index)
if err != nil {
return err
}
err = idx.Encode(blob)
if err != nil {
return err
}
err = blob.Close()
if err != nil {
return err
}
sid := blob.ID()
debug.Log("Repo.SaveIndex", "Saved index %d as %v", i, sid.Str())
}
return nil
}
// SaveIndex saves all new indexes in the backend.
func (r *Repository) SaveIndex() error {
return r.saveIndex(r.idx.NotFinalIndexes()...)
}
// SaveFullIndex saves all full indexes in the backend.
func (r *Repository) SaveFullIndex() error {
return r.saveIndex(r.idx.FullIndexes()...)
}
const loadIndexParallelism = 20
// LoadIndex loads all index files from the backend in parallel and stores them
// in the master 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.Insert(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 := LoadIndexWithDecoder(repo, id, DecodeIndex)
if err == nil {
return idx, nil
}
if err == ErrOldIndexFormat {
fmt.Fprintf(os.Stderr, "index %v has old format\n", id[:10])
return LoadIndexWithDecoder(repo, id, DecodeOldIndex)
}
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)
}
// LoadIndexWithDecoder loads the index and decodes it with fn.
func LoadIndexWithDecoder(repo *Repository, id string, fn func(io.Reader) (*Index, error)) (*Index, error) {
debug.Log("LoadIndexWithDecoder", "Loading index %v", id[:8])
rd, err := repo.GetDecryptReader(backend.Index, id)
if err != nil {
return nil, err
}
defer rd.Close()
idx, err := fn(rd)
if err != nil {
debug.Log("LoadIndexWithDecoder", "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()
}