245 lines
5.1 KiB
Go
245 lines
5.1 KiB
Go
package restic
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import (
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"encoding/json"
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"errors"
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"fmt"
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"github.com/restic/restic/backend"
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)
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var ErrWrongData = errors.New("wrong data decrypt, checksum does not match")
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type ContentHandler struct {
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s Server
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bl *BlobList
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}
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// NewContentHandler creates a new content handler.
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func NewContentHandler(s Server) *ContentHandler {
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ch := &ContentHandler{
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s: s,
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bl: NewBlobList(),
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}
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return ch
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}
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// LoadSnapshot adds all blobs from a snapshot into the content handler and returns the snapshot.
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func (ch *ContentHandler) LoadSnapshot(id backend.ID) (*Snapshot, error) {
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sn, err := LoadSnapshot(ch, id)
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if err != nil {
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return nil, err
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}
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sn.bl, err = LoadBlobList(ch, sn.Map)
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if err != nil {
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return nil, err
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}
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ch.bl.Merge(sn.bl)
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return sn, nil
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}
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// LoadAllMaps adds all blobs from all snapshots that can be decrypted
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// into the content handler.
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func (ch *ContentHandler) LoadAllMaps() error {
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// add all maps from all snapshots that can be decrypted to the storage map
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err := backend.EachID(ch.s, backend.Map, func(id backend.ID) {
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bl, err := LoadBlobList(ch, id)
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if err != nil {
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return
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}
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ch.bl.Merge(bl)
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})
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if err != nil {
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return err
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}
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return nil
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}
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// Save encrypts data and stores it to the backend as type t. If the data was
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// already saved before, the blob is returned.
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func (ch *ContentHandler) Save(t backend.Type, data []byte) (Blob, error) {
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// compute plaintext hash
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id := backend.Hash(data)
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// test if the hash is already in the backend
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blob, err := ch.bl.Find(Blob{ID: id})
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if err == nil {
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id.Free()
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return blob, nil
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}
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// else create a new blob
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blob = Blob{
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ID: id,
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Size: uint64(len(data)),
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}
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var ciphertext []byte
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// for a bloblist/map, use a larger buffer
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if t == backend.Map {
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ciphertext = make([]byte, len(data)+CiphertextExtension)
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} else {
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// otherwise use buffer from pool
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ciphertext = GetChunkBuf("ch.Save()")
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defer FreeChunkBuf("ch.Save()", ciphertext)
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}
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// encrypt blob
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n, err := ch.s.Encrypt(ciphertext, data)
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if err != nil {
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return Blob{}, err
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}
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ciphertext = ciphertext[:n]
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// save blob
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sid, err := ch.s.Create(t, ciphertext)
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if err != nil {
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return Blob{}, err
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}
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blob.Storage = sid
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blob.StorageSize = uint64(len(ciphertext))
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// insert blob into the storage map
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ch.bl.Insert(blob)
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return blob, nil
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}
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// SaveJSON serialises item as JSON and uses Save() to store it to the backend as type t.
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func (ch *ContentHandler) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
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// convert to json
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data, err := json.Marshal(item)
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if err != nil {
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return Blob{}, err
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}
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// compress and save data
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return ch.Save(t, backend.Compress(data))
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}
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// Load tries to load and decrypt content identified by t and id from the backend.
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func (ch *ContentHandler) Load(t backend.Type, id backend.ID) ([]byte, error) {
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if t == backend.Snapshot {
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// load data
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buf, err := ch.s.Get(t, id)
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if err != nil {
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return nil, err
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}
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// decrypt
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buf, err = ch.s.Decrypt(buf)
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if err != nil {
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return nil, err
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}
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return buf, nil
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}
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// lookup storage hash
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blob, err := ch.bl.Find(Blob{ID: id})
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if err != nil {
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return nil, fmt.Errorf("Storage ID %s not found", id)
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}
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// load data
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buf, err := ch.s.Get(t, blob.Storage)
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if err != nil {
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return nil, err
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}
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// check length
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if len(buf) != int(blob.StorageSize) {
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return nil, errors.New("Invalid storage length")
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}
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// decrypt
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buf, err = ch.s.Decrypt(buf)
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if err != nil {
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return nil, err
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}
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// check length
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if len(buf) != int(blob.Size) {
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return nil, errors.New("Invalid length")
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}
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// check SHA256 sum
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if !id.Equal(backend.Hash(buf)) {
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return nil, ErrWrongData
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}
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return buf, nil
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}
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// Lookup returns the storage ID for the given blob
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func (ch *ContentHandler) Lookup(id backend.ID) (backend.ID, error) {
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// lookup storage hash
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blob, err := ch.bl.Find(Blob{ID: id})
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if err != nil {
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return nil, err
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}
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return blob.Storage, nil
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}
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// LoadJSON calls Load() to get content from the backend and afterwards calls
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// json.Unmarshal on the item.
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func (ch *ContentHandler) LoadJSON(t backend.Type, id backend.ID, item interface{}) error {
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// load from backend
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buf, err := ch.Load(t, id)
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if err != nil {
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return err
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}
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// inflate and unmarshal
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err = json.Unmarshal(backend.Uncompress(buf), item)
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return err
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}
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// LoadJSONRaw loads data with the given storage id and type from the backend,
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// decrypts it and calls json.Unmarshal on the item.
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func (ch *ContentHandler) LoadJSONRaw(t backend.Type, id backend.ID, item interface{}) error {
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// load data
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buf, err := ch.s.Get(t, id)
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if err != nil {
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return err
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}
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// decrypt
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buf, err = ch.s.Decrypt(buf)
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if err != nil {
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return err
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}
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// inflate and unmarshal
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err = json.Unmarshal(backend.Uncompress(buf), item)
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return err
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}
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// Test checks if a blob is in the repository. For Data and Tree blobs, the
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// storage ID is looked up.
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func (ch *ContentHandler) Test(t backend.Type, id backend.ID) (bool, error) {
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if t == backend.Data || t == backend.Tree {
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// lookup storage id
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// lookup storage hash
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blob, err := ch.bl.Find(Blob{ID: id})
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if err != nil {
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return false, fmt.Errorf("Storage ID %s not found", id)
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}
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id = blob.Storage
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}
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return ch.s.Test(t, id)
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}
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