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mirror of https://github.com/octoleo/restic.git synced 2024-12-23 11:28:54 +00:00
restic/repository/repository.go
2015-05-17 20:58:22 +02:00

690 lines
15 KiB
Go

package repository
import (
"bytes"
"crypto/rand"
"crypto/sha256"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"sync"
"github.com/restic/restic/backend"
"github.com/restic/restic/chunker"
"github.com/restic/restic/crypto"
"github.com/restic/restic/debug"
"github.com/restic/restic/pack"
)
// Config contains the configuration for a repository.
type Config struct {
Version uint `json:"version"`
ID string `json:"id"`
ChunkerPolynomial chunker.Pol `json:"chunker_polynomial"`
}
// 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
}
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 (s *Repository) Find(t backend.Type, prefix string) (string, error) {
return backend.Find(s.be, t, prefix)
}
// PrefixLength returns the number of bytes required so that all prefixes of
// all IDs of type t are unique.
func (s *Repository) PrefixLength(t backend.Type) (int, error) {
return backend.PrefixLength(s.be, t)
}
// Load tries to load and decrypt content identified by t and id from the
// backend.
func (s *Repository) Load(t backend.Type, id backend.ID) ([]byte, error) {
debug.Log("Repo.Load", "load %v with id %v", t, id.Str())
// load blob from pack
rd, err := s.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 := s.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.
func (s *Repository) LoadBlob(t pack.BlobType, id backend.ID) ([]byte, error) {
debug.Log("Repo.LoadBlob", "load %v with id %v", t, id.Str())
// lookup pack
packID, tpe, offset, length, err := s.idx.Lookup(id)
if err != nil {
debug.Log("Repo.LoadBlob", "id %v not found in index: %v", id.Str(), err)
return nil, err
}
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 := s.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
}
buf, err := ioutil.ReadAll(rd)
if err != nil {
return nil, err
}
err = rd.Close()
if err != nil {
return nil, err
}
// decrypt
plain, err := s.Decrypt(buf)
if err != nil {
return nil, err
}
// check hash
if !backend.Hash(plain).Equal(id) {
return nil, errors.New("invalid data returned")
}
return plain, nil
}
// LoadJSONUnpacked decrypts the data and afterwards calls json.Unmarshal on
// the item.
func (s *Repository) LoadJSONUnpacked(t backend.Type, id backend.ID, item interface{}) error {
// load blob from backend
rd, err := s.be.Get(t, id.String())
if err != nil {
return err
}
defer rd.Close()
// decrypt
decryptRd, err := crypto.DecryptFrom(s.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 (s *Repository) LoadJSONPack(t pack.BlobType, id backend.ID, item interface{}) error {
// lookup pack
packID, _, offset, length, err := s.idx.Lookup(id)
if err != nil {
return err
}
// load blob from pack
rd, err := s.be.GetReader(backend.Data, packID.String(), offset, length)
if err != nil {
return err
}
defer rd.Close()
// decrypt
decryptRd, err := crypto.DecryptFrom(s.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
}
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 (s *Repository) findPacker(size uint) (*pack.Packer, error) {
s.pm.Lock()
defer s.pm.Unlock()
// search for a suitable packer
if len(s.packs) > 0 {
debug.Log("Repo.findPacker", "searching packer for %d bytes\n", size)
for i, p := range s.packs {
if p.Size()+size < maxPackSize {
debug.Log("Repo.findPacker", "found packer %v", p)
// remove from list
s.packs = append(s.packs[:i], s.packs[i+1:]...)
return p, nil
}
}
}
// no suitable packer found, return new
blob, err := s.be.Create()
if err != nil {
return nil, err
}
debug.Log("Repo.findPacker", "create new pack %p", blob)
return pack.NewPacker(s.key, blob), nil
}
// insertPacker appends p to s.packs.
func (s *Repository) insertPacker(p *pack.Packer) {
s.pm.Lock()
defer s.pm.Unlock()
s.packs = append(s.packs, p)
debug.Log("Repo.insertPacker", "%d packers\n", len(s.packs))
}
// savePacker stores p in the backend.
func (s *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())
s.idx.Store(b.Type, b.ID, sid, b.Offset, uint(b.Length))
}
return nil
}
// countPacker returns the number of open (unfinished) packers.
func (s *Repository) countPacker() int {
s.pm.Lock()
defer s.pm.Unlock()
return len(s.packs)
}
// Save 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 (s *Repository) Save(t pack.BlobType, data []byte, id backend.ID) (backend.ID, error) {
if id == nil {
// compute plaintext hash
id = backend.Hash(data)
}
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 := s.Encrypt(ciphertext, data)
if err != nil {
return nil, err
}
// find suitable packer and add blob
packer, err := s.findPacker(uint(len(ciphertext)))
if err != nil {
return nil, err
}
// save ciphertext
packer.Add(t, id, bytes.NewReader(ciphertext))
// 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.
s.idx.Store(t, id, nil, 0, 0)
debug.Log("Repo.Save", "saving stub for %v (%v) in index", id.Str, t)
// if the pack is not full enough and there are less than maxPackers
// packers, put back to the list
if packer.Size() < minPackSize && s.countPacker() < maxPackers {
debug.Log("Repo.Save", "pack is not full enough (%d bytes)", packer.Size())
s.insertPacker(packer)
return id, nil
}
// else write the pack to the backend
return id, s.savePacker(packer)
}
// SaveFrom encrypts data read from rd and stores it in a pack in the backend as type t.
func (s *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 = s.Save(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 (s *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 nil, fmt.Errorf("json.Encode: %v", err)
}
buf = wr.Bytes()
return s.Save(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 (s *Repository) SaveJSONUnpacked(t backend.Type, item interface{}) (backend.ID, error) {
// create file
blob, err := s.be.Create()
if err != nil {
return nil, err
}
debug.Log("Repo.SaveJSONUnpacked", "create new file %p", blob)
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(s.key, hw)
enc := json.NewEncoder(ewr)
err = enc.Encode(item)
if err != nil {
return nil, fmt.Errorf("json.Encode: %v", err)
}
err = ewr.Close()
if err != nil {
return nil, err
}
// finalize blob in the backend
sid := backend.ID(hw.Sum(nil))
err = blob.Finalize(t, sid.String())
if err != nil {
return nil, err
}
return sid, nil
}
// Flush saves all remaining packs.
func (s *Repository) Flush() error {
s.pm.Lock()
defer s.pm.Unlock()
debug.Log("Repo.Flush", "manually flushing %d packs", len(s.packs))
for _, p := range s.packs {
err := s.savePacker(p)
if err != nil {
return err
}
}
s.packs = s.packs[:0]
return nil
}
func (s *Repository) Backend() backend.Backend {
return s.be
}
func (s *Repository) Index() *Index {
return s.idx
}
// SetIndex instructs the repository to use the given index.
func (s *Repository) SetIndex(i *Index) {
s.idx = i
}
// SaveIndex saves all new packs in the index in the backend, returned is the
// storage ID.
func (s *Repository) SaveIndex() (backend.ID, error) {
debug.Log("Repo.SaveIndex", "Saving index")
// create blob
blob, err := s.be.Create()
if err != nil {
return nil, err
}
debug.Log("Repo.SaveIndex", "create new pack %p", blob)
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(s.key, hw)
err = s.idx.Encode(ewr)
if err != nil {
return nil, err
}
err = ewr.Close()
if err != nil {
return nil, err
}
// finalize blob in the backend
sid := backend.ID(hw.Sum(nil))
err = blob.Finalize(backend.Index, sid.String())
if err != nil {
return nil, err
}
debug.Log("Repo.SaveIndex", "Saved index as %v", sid.Str())
return sid, nil
}
// LoadIndex loads all index files from the backend and merges them with the
// current index.
func (s *Repository) LoadIndex() error {
debug.Log("Repo.LoadIndex", "Loading index")
done := make(chan struct{})
defer close(done)
for id := range s.be.List(backend.Index, done) {
err := s.loadIndex(id)
if err != nil {
return err
}
}
return nil
}
// loadIndex loads the index id and merges it with the currently used index.
func (s *Repository) loadIndex(id string) error {
debug.Log("Repo.loadIndex", "Loading index %v", id[:8])
before := len(s.idx.pack)
rd, err := s.be.Get(backend.Index, id)
defer rd.Close()
if err != nil {
return err
}
// decrypt
decryptRd, err := crypto.DecryptFrom(s.key, rd)
defer decryptRd.Close()
if err != nil {
return err
}
idx, err := DecodeIndex(decryptRd)
if err != nil {
debug.Log("Repo.loadIndex", "error while decoding index %v: %v", id, err)
return err
}
s.idx.Merge(idx)
after := len(s.idx.pack)
debug.Log("Repo.loadIndex", "Loaded index %v, added %v blobs", id[:8], after-before)
return nil
}
const repositoryIDSize = sha256.Size
const RepoVersion = 1
func createConfig(s *Repository) (err error) {
s.Config.ChunkerPolynomial, err = chunker.RandomPolynomial()
if err != nil {
return err
}
newID := make([]byte, repositoryIDSize)
_, err = io.ReadFull(rand.Reader, newID)
if err != nil {
return err
}
s.Config.ID = hex.EncodeToString(newID)
s.Config.Version = RepoVersion
debug.Log("Repo.createConfig", "New config: %#v", s.Config)
_, err = s.SaveJSONUnpacked(backend.Config, s.Config)
return err
}
func (s *Repository) loadConfig(cfg *Config) error {
err := s.LoadJSONUnpacked(backend.Config, nil, cfg)
if err != nil {
return err
}
if cfg.Version != RepoVersion {
return errors.New("unsupported repository version")
}
if !cfg.ChunkerPolynomial.Irreducible() {
return errors.New("invalid chunker polynomial")
}
return nil
}
// SearchKey finds a key with the supplied password, afterwards the config is
// read and parsed.
func (s *Repository) SearchKey(password string) error {
key, err := SearchKey(s, password)
if err != nil {
return err
}
s.key = key.master
s.keyName = key.Name()
return s.loadConfig(&s.Config)
}
// Init creates a new master key with the supplied password and initializes the
// repository config.
func (s *Repository) Init(password string) error {
has, err := s.be.Test(backend.Config, "")
if err != nil {
return err
}
if has {
return errors.New("repository master key and config already initialized")
}
key, err := createMasterKey(s, password)
if err != nil {
return err
}
s.key = key.master
s.keyName = key.Name()
return createConfig(s)
}
func (s *Repository) Decrypt(ciphertext []byte) ([]byte, error) {
if s.key == nil {
return nil, errors.New("key for repository not set")
}
return crypto.Decrypt(s.key, nil, ciphertext)
}
func (s *Repository) Encrypt(ciphertext, plaintext []byte) ([]byte, error) {
if s.key == nil {
return nil, errors.New("key for repository not set")
}
return crypto.Encrypt(s.key, ciphertext, plaintext)
}
func (s *Repository) Key() *crypto.Key {
return s.key
}
func (s *Repository) KeyName() string {
return s.keyName
}
// Count returns the number of blobs of a given type in the backend.
func (s *Repository) Count(t backend.Type) (n uint) {
for _ = range s.be.List(t, nil) {
n++
}
return
}
func (s *Repository) list(t backend.Type, done <-chan struct{}, out chan<- backend.ID) {
defer close(out)
in := s.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
}
}
}
func (s *Repository) List(t backend.Type, done <-chan struct{}) <-chan backend.ID {
outCh := make(chan backend.ID)
go s.list(t, done, outCh)
return outCh
}
func (s *Repository) Delete() error {
if b, ok := s.be.(backend.Deleter); ok {
return b.Delete()
}
return errors.New("Delete() called for backend that does not implement this method")
}
func (s *Repository) Close() error {
return s.be.Close()
}