244 lines
7.1 KiB
Haskell
244 lines
7.1 KiB
Haskell
{- git-annex hashing backends
|
|
-
|
|
- Copyright 2011-2015 Joey Hess <id@joeyh.name>
|
|
-
|
|
- Licensed under the GNU GPL version 3 or higher.
|
|
-}
|
|
|
|
{-# LANGUAGE CPP, BangPatterns #-}
|
|
|
|
module Backend.Hash (
|
|
backends,
|
|
testKeyBackend,
|
|
) where
|
|
|
|
import Annex.Common
|
|
import qualified Annex
|
|
import Types.Backend
|
|
import Types.KeySource
|
|
import Utility.Hash
|
|
import Utility.ExternalSHA
|
|
|
|
import qualified Build.SysConfig as SysConfig
|
|
import qualified Data.ByteString.Lazy as L
|
|
import Data.Char
|
|
|
|
data Hash
|
|
= MD5Hash
|
|
| SHA1Hash
|
|
| SHA2Hash HashSize
|
|
| SHA3Hash HashSize
|
|
| SkeinHash HashSize
|
|
type HashSize = Int
|
|
|
|
{- Order is slightly significant; want SHA256 first, and more general
|
|
- sizes earlier. -}
|
|
hashes :: [Hash]
|
|
hashes = concat
|
|
[ map SHA2Hash [256, 512, 224, 384]
|
|
#ifdef WITH_CRYPTONITE
|
|
, map SHA3Hash [256, 512, 224, 384]
|
|
#endif
|
|
, map SkeinHash [256, 512]
|
|
, [SHA1Hash]
|
|
, [MD5Hash]
|
|
]
|
|
|
|
{- The SHA256E backend is the default, so genBackendE comes first. -}
|
|
backends :: [Backend]
|
|
backends = concatMap (\h -> [genBackendE h, genBackend h]) hashes
|
|
|
|
genBackend :: Hash -> Backend
|
|
genBackend hash = Backend
|
|
{ name = hashName hash
|
|
, getKey = keyValue hash
|
|
, verifyKeyContent = Just $ checkKeyChecksum hash
|
|
, canUpgradeKey = Just needsUpgrade
|
|
, fastMigrate = Just trivialMigrate
|
|
, isStableKey = const True
|
|
}
|
|
|
|
genBackendE :: Hash -> Backend
|
|
genBackendE hash = (genBackend hash)
|
|
{ name = hashNameE hash
|
|
, getKey = keyValueE hash
|
|
}
|
|
|
|
hashName :: Hash -> String
|
|
hashName MD5Hash = "MD5"
|
|
hashName SHA1Hash = "SHA1"
|
|
hashName (SHA2Hash size) = "SHA" ++ show size
|
|
hashName (SHA3Hash size) = "SHA3_" ++ show size
|
|
hashName (SkeinHash size) = "SKEIN" ++ show size
|
|
|
|
hashNameE :: Hash -> String
|
|
hashNameE hash = hashName hash ++ "E"
|
|
|
|
{- A key is a hash of its contents. -}
|
|
keyValue :: Hash -> KeySource -> Annex (Maybe Key)
|
|
keyValue hash source = do
|
|
let file = contentLocation source
|
|
filesize <- liftIO $ getFileSize file
|
|
s <- hashFile hash file filesize
|
|
return $ Just $ stubKey
|
|
{ keyName = s
|
|
, keyBackendName = hashName hash
|
|
, keySize = Just filesize
|
|
}
|
|
|
|
{- Extension preserving keys. -}
|
|
keyValueE :: Hash -> KeySource -> Annex (Maybe Key)
|
|
keyValueE hash source = keyValue hash source >>= maybe (return Nothing) addE
|
|
where
|
|
addE k = return $ Just $ k
|
|
{ keyName = keyName k ++ selectExtension (keyFilename source)
|
|
, keyBackendName = hashNameE hash
|
|
}
|
|
|
|
selectExtension :: FilePath -> String
|
|
selectExtension f
|
|
| null es = ""
|
|
| otherwise = intercalate "." ("":es)
|
|
where
|
|
es = filter (not . null) $ reverse $
|
|
take 2 $ takeWhile shortenough $
|
|
reverse $ split "." $ filter validExtension $ takeExtensions f
|
|
shortenough e = length e <= 4 -- long enough for "jpeg"
|
|
|
|
{- A key's checksum is checked during fsck. -}
|
|
checkKeyChecksum :: Hash -> Key -> FilePath -> Annex Bool
|
|
checkKeyChecksum hash key file = catchIOErrorType HardwareFault hwfault $ do
|
|
fast <- Annex.getState Annex.fast
|
|
mstat <- liftIO $ catchMaybeIO $ getFileStatus file
|
|
case (mstat, fast) of
|
|
(Just stat, False) -> do
|
|
filesize <- liftIO $ getFileSize' file stat
|
|
showAction "checksum"
|
|
check <$> hashFile hash file filesize
|
|
_ -> return True
|
|
where
|
|
expected = keyHash key
|
|
check s
|
|
| s == expected = True
|
|
{- A bug caused checksums to be prefixed with \ in some
|
|
- cases; still accept these as legal now that the bug has been
|
|
- fixed. -}
|
|
| '\\' : s == expected = True
|
|
| otherwise = False
|
|
|
|
hwfault e = do
|
|
warning $ "hardware fault: " ++ show e
|
|
return False
|
|
|
|
keyHash :: Key -> String
|
|
keyHash key = dropExtensions (keyName key)
|
|
|
|
validExtension :: Char -> Bool
|
|
validExtension c
|
|
| isAlphaNum c = True
|
|
| c == '.' = True
|
|
| otherwise = False
|
|
|
|
{- Upgrade keys that have the \ prefix on their sha due to a bug, or
|
|
- that contain non-alphanumeric characters in their extension. -}
|
|
needsUpgrade :: Key -> Bool
|
|
needsUpgrade key = "\\" `isPrefixOf` keyHash key ||
|
|
any (not . validExtension) (takeExtensions $ keyName key)
|
|
|
|
trivialMigrate :: Key -> Backend -> AssociatedFile -> Maybe Key
|
|
trivialMigrate oldkey newbackend afile
|
|
{- Fast migration from hashE to hash backend. -}
|
|
| keyBackendName oldkey == name newbackend ++ "E" = Just $ oldkey
|
|
{ keyName = keyHash oldkey
|
|
, keyBackendName = name newbackend
|
|
}
|
|
{- Fast migration from hash to hashE backend. -}
|
|
| keyBackendName oldkey ++"E" == name newbackend = case afile of
|
|
Nothing -> Nothing
|
|
Just file -> Just $ oldkey
|
|
{ keyName = keyHash oldkey ++ selectExtension file
|
|
, keyBackendName = name newbackend
|
|
}
|
|
| otherwise = Nothing
|
|
|
|
hashFile :: Hash -> FilePath -> Integer -> Annex String
|
|
hashFile hash file filesize = go hash
|
|
where
|
|
go MD5Hash = use md5Hasher
|
|
go SHA1Hash = usehasher 1
|
|
go (SHA2Hash hashsize) = usehasher hashsize
|
|
go (SHA3Hash hashsize) = use (sha3Hasher hashsize)
|
|
go (SkeinHash hashsize) = use (skeinHasher hashsize)
|
|
|
|
use hasher = liftIO $ do
|
|
hdl <- openBinaryFile file ReadMode
|
|
b <- L.hGetContents hdl
|
|
let !hsh = hasher b
|
|
hClose hdl
|
|
return hsh
|
|
|
|
usehasher hashsize = case shaHasher hashsize filesize of
|
|
Left sha -> use sha
|
|
Right (external, internal) -> do
|
|
v <- liftIO $ externalSHA external hashsize file
|
|
case v of
|
|
Right r -> return r
|
|
Left e -> do
|
|
warning e
|
|
-- fall back to internal since
|
|
-- external command failed
|
|
use internal
|
|
|
|
shaHasher :: HashSize -> Integer -> Either (L.ByteString -> String) (String, L.ByteString -> String)
|
|
shaHasher hashsize filesize
|
|
| hashsize == 1 = use SysConfig.sha1 sha1
|
|
| hashsize == 256 = use SysConfig.sha256 sha2_256
|
|
| hashsize == 224 = use SysConfig.sha224 sha2_224
|
|
| hashsize == 384 = use SysConfig.sha384 sha2_384
|
|
| hashsize == 512 = use SysConfig.sha512 sha2_512
|
|
| otherwise = error $ "unsupported SHA size " ++ show hashsize
|
|
where
|
|
use Nothing hasher = Left $ usehasher hasher
|
|
use (Just c) hasher
|
|
{- Use builtin, but slightly slower hashing for
|
|
- smallish files. Cryptohash benchmarks 90 to 101%
|
|
- faster than external hashers, depending on the hash
|
|
- and system. So there is no point forking an external
|
|
- process unless the file is large. -}
|
|
| filesize < 1048576 = Left $ usehasher hasher
|
|
| otherwise = Right (c, usehasher hasher)
|
|
usehasher hasher = show . hasher
|
|
|
|
sha3Hasher :: HashSize -> (L.ByteString -> String)
|
|
sha3Hasher hashsize
|
|
#ifdef WITH_CRYPTONITE
|
|
| hashsize == 256 = show . sha3_256
|
|
| hashsize == 224 = show . sha3_224
|
|
| hashsize == 384 = show . sha3_384
|
|
| hashsize == 512 = show . sha3_512
|
|
#endif
|
|
| otherwise = error $ "unsupported SHA3 size " ++ show hashsize
|
|
|
|
skeinHasher :: HashSize -> (L.ByteString -> String)
|
|
skeinHasher hashsize
|
|
| hashsize == 256 = show . skein256
|
|
| hashsize == 512 = show . skein512
|
|
| otherwise = error $ "unsupported SKEIN size " ++ show hashsize
|
|
|
|
md5Hasher :: L.ByteString -> String
|
|
md5Hasher = show . md5
|
|
|
|
{- A varient of the SHA256E backend, for testing that needs special keys
|
|
- that cannot collide with legitimate keys in the repository.
|
|
-
|
|
- This is accomplished by appending a special extension to the key,
|
|
- that is not one that selectExtension would select (due to being too
|
|
- long).
|
|
-}
|
|
testKeyBackend :: Backend
|
|
testKeyBackend =
|
|
let b = genBackendE (SHA2Hash 256)
|
|
in b { getKey = (fmap addE) <$$> getKey b }
|
|
where
|
|
addE k = k { keyName = keyName k ++ longext }
|
|
longext = ".this-is-a-test-key"
|