restic/repository/repository.go

566 lines
14 KiB
Go

package repository
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"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
*packerManager
}
// New returns a new repository with backend be.
func New(be backend.Backend) *Repository {
return &Repository{
be: be,
idx: NewMasterIndex(),
packerManager: &packerManager{
be: be,
},
}
}
// 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())
h := backend.Handle{Type: t, Name: id.String()}
buf, err := backend.LoadAll(r.be, h, nil)
if err != nil {
debug.Log("Repo.Load", "error loading %v: %v", id.Str(), err)
return nil, err
}
if t != backend.Config && !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
blob, 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
}
plaintextBufSize := uint(cap(plaintextBuf))
if blob.PlaintextLength() > plaintextBufSize {
debug.Log("Repo.LoadBlob", "need to expand buffer: want %d bytes, got %d",
blob.PlaintextLength(), plaintextBufSize)
plaintextBuf = make([]byte, blob.PlaintextLength())
}
if blob.Type != t {
debug.Log("Repo.LoadBlob", "wrong type returned for %v: wanted %v, got %v", id.Str(), t, blob.Type)
return nil, fmt.Errorf("blob has wrong type %v (wanted: %v)", blob.Type, t)
}
debug.Log("Repo.LoadBlob", "id %v found: %v", id.Str(), blob)
// load blob from pack
h := backend.Handle{Type: backend.Data, Name: blob.PackID.String()}
ciphertextBuf := make([]byte, blob.Length)
n, err := r.be.Load(h, ciphertextBuf, int64(blob.Offset))
if err != nil {
debug.Log("Repo.LoadBlob", "error loading blob %v: %v", blob, err)
return nil, err
}
if uint(n) != blob.Length {
debug.Log("Repo.LoadBlob", "error loading blob %v: wrong length returned, want %d, got %d",
blob.Length, uint(n))
return nil, errors.New("wrong length returned")
}
// 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
}
// closeOrErr calls cl.Close() and sets err to the returned error value if
// itself is not yet set.
func closeOrErr(cl io.Closer, err *error) {
e := cl.Close()
if *err != nil {
return
}
*err = e
}
// LoadJSONUnpacked decrypts the data and afterwards calls json.Unmarshal on
// the item.
func (r *Repository) LoadJSONUnpacked(t backend.Type, id backend.ID, item interface{}) (err error) {
buf, err := r.LoadAndDecrypt(t, id)
if err != nil {
return err
}
return json.Unmarshal(buf, item)
}
// 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{}) (err error) {
buf, err := r.LoadBlob(t, id, nil)
if err != nil {
return err
}
return json.Unmarshal(buf, item)
}
// LookupBlobSize returns the size of blob id.
func (r *Repository) LookupBlobSize(id backend.ID) (uint, error) {
return r.idx.LookupSize(id)
}
// 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. When
// ignoreDuplicates is true, blobs already in the index will be saved again.
func (r *Repository) SaveAndEncrypt(t pack.BlobType, data []byte, id *backend.ID, ignoreDuplicates bool) (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, ignoreDuplicates)
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, false)
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, false)
}
// 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) {
debug.Log("Repo.SaveJSONUnpacked", "save new blob %v", t)
plaintext, err := json.Marshal(item)
if err != nil {
return backend.ID{}, fmt.Errorf("json.Encode: %v", err)
}
return r.SaveUnpacked(t, plaintext)
}
// SaveUnpacked encrypts data and stores it in the backend. Returned is the
// storage hash.
func (r *Repository) SaveUnpacked(t backend.Type, p []byte) (id backend.ID, err error) {
ciphertext := make([]byte, len(p)+crypto.Extension)
ciphertext, err = r.Encrypt(ciphertext, p)
if err != nil {
return backend.ID{}, err
}
id = backend.Hash(ciphertext)
h := backend.Handle{Type: t, Name: id.String()}
err = r.be.Save(h, ciphertext)
if err != nil {
debug.Log("Repo.SaveJSONUnpacked", "error saving blob %v: %v", h, err)
return backend.ID{}, err
}
debug.Log("Repo.SaveJSONUnpacked", "blob %v saved", h)
return id, 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
}
// SaveIndex saves an index in the repository.
func SaveIndex(repo *Repository, index *Index) (backend.ID, error) {
buf := bytes.NewBuffer(nil)
err := index.Finalize(buf)
if err != nil {
return backend.ID{}, err
}
return repo.SaveUnpacked(backend.Index, buf.Bytes())
}
// 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)
sid, err := SaveIndex(r, idx)
if err != nil {
return err
}
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
}
// 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.packerManager.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.packerManager.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()
}