summaryrefslogtreecommitdiff
path: root/Remote/Helper/ChunkedEncryptable.hs
blob: 024a5330940db6133bbcd1408640783a0d3d255c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
{- Remotes that support both chunking and encryption.
 -
 - Copyright 2014 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ImpredicativeTypes #-}
{-# LANGUAGE FlexibleContexts #-}

module Remote.Helper.ChunkedEncryptable (
	Preparer,
	Storer,
	Retriever,
	simplyPrepare,
	ContentSource,
	checkPrepare,
	fileStorer,
	byteStorer,
	fileRetriever,
	byteRetriever,
	chunkedEncryptableRemote,
	storeKeyDummy,
	retreiveKeyFileDummy,
	module X
) where

import Common.Annex
import Types.StoreRetrieve
import Types.Remote
import Crypto
import Config.Cost
import Utility.Metered
import Remote.Helper.Chunked as X
import Remote.Helper.Encryptable as X
import Annex.Content
import Annex.Exception

import qualified Data.ByteString.Lazy as L

simplyPrepare :: helper -> Preparer helper
simplyPrepare helper _ a = a $ Just helper

checkPrepare :: (Key -> Annex Bool) -> helper -> Preparer helper
checkPrepare checker helper k a = ifM (checker k)
	( a (Just helper)
	, a Nothing
	)

{- Modifies a base Remote to support both chunking and encryption.
 -}
chunkedEncryptableRemote
	:: RemoteConfig
	-> Preparer Storer
	-> Preparer Retriever
	-> Remote
	-> Remote
chunkedEncryptableRemote c preparestorer prepareretriever baser = encr
  where
	encr = baser
		{ storeKey = \k _f p -> cip >>= storeKeyGen k p
		, retrieveKeyFile = \k _f d p -> cip >>= retrieveKeyFileGen k d p
		, retrieveKeyFileCheap = \k d -> cip >>= maybe
			(retrieveKeyFileCheap baser k d)
			(\_ -> return False)
		, removeKey = \k -> cip >>= removeKeyGen k
		, hasKey = \k -> cip >>= hasKeyGen k
		, cost = maybe
			(cost baser)
			(const $ cost baser + encryptedRemoteCostAdj)
			(extractCipher c)
		}
	cip = cipherKey c
	chunkconfig = chunkConfig c
	gpgopts = getGpgEncParams encr

	safely a = catchNonAsyncAnnex a (\e -> warning (show e) >> return False)

	-- chunk, then encrypt, then feed to the storer
	storeKeyGen k p enc =
		safely $ preparestorer k $ safely . go
	  where
		go (Just storer) = sendAnnex k rollback $ \src ->
			metered (Just p) k $ \p' ->
				storeChunks (uuid baser) chunkconfig k src p'
					(storechunk enc storer)
					(hasKey baser)
		go Nothing = return False
		rollback = void $ removeKey encr k

	storechunk Nothing storer k content p = storer k content p
	storechunk (Just (cipher, enck)) storer k content p =
		withBytes content $ \b ->
			encrypt gpgopts cipher (feedBytes b) $
				readBytes $ \encb ->
					storer (enck k) (ByteContent encb) p

	-- call retriever to get chunks; decrypt them; stream to dest file
	retrieveKeyFileGen k dest p enc =
		safely $ prepareretriever k $ safely . go
	  where
	  	go (Just retriever) = metered (Just p) k $ \p' ->
			retrieveChunks retriever (uuid baser) chunkconfig
				enck k dest p' sink
		go Nothing = return False
		sink h mp b = do
			let write = case mp of
				Just p' -> meteredWrite p' h
				Nothing -> L.hPut h
			case enc of
				Nothing -> write b
				Just (cipher, _) ->
					decrypt cipher (feedBytes b) $
						readBytes write
		enck = maybe id snd enc

	removeKeyGen k enc = removeChunks remover (uuid baser) chunkconfig enck k
	  where
		enck = maybe id snd enc
		remover = removeKey baser

	hasKeyGen k enc = hasKeyChunks checker (uuid baser) chunkconfig enck k
	  where
		enck = maybe id snd enc
		checker = hasKey baser

{- The base Remote that is provided to chunkedEncryptableRemote
 - needs to have storeKey and retreiveKeyFile methods, but they are
 - never actually used (since chunkedEncryptableRemote replaces
 - them). Here are some dummy ones.
 -}
storeKeyDummy :: Key -> AssociatedFile -> MeterUpdate -> Annex Bool
storeKeyDummy _ _ _ = return False
retreiveKeyFileDummy :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Bool
retreiveKeyFileDummy _ _ _ _ = return False