{-# LANGUAGE ScopedTypeVariables #-}
module Crypto.Random.Entropy.Unix
( DevRandom
, DevURandom
) where
import Foreign.Ptr
import Data.Word (Word8)
import Crypto.Random.Entropy.Source
import Control.Exception as E
import System.IO
type H = Handle
type DeviceName = String
newtype DevRandom = DevRandom DeviceName
newtype DevURandom = DevURandom DeviceName
instance EntropySource DevRandom where
entropyOpen :: IO (Maybe DevRandom)
entropyOpen = (DeviceName -> DevRandom) -> Maybe DeviceName -> Maybe DevRandom
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap DeviceName -> DevRandom
DevRandom (Maybe DeviceName -> Maybe DevRandom)
-> IO (Maybe DeviceName) -> IO (Maybe DevRandom)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` DeviceName -> IO (Maybe DeviceName)
testOpen DeviceName
"/dev/random"
entropyGather :: DevRandom -> Ptr Word8 -> Int -> IO Int
entropyGather (DevRandom DeviceName
name) Ptr Word8
ptr Int
n =
DeviceName -> (H -> IO Int) -> IO Int
forall a. DeviceName -> (H -> IO a) -> IO a
withDev DeviceName
name ((H -> IO Int) -> IO Int) -> (H -> IO Int) -> IO Int
forall a b. (a -> b) -> a -> b
$ \H
h -> H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropyNonBlock H
h Ptr Word8
ptr Int
n
entropyClose :: DevRandom -> IO ()
entropyClose (DevRandom DeviceName
_) = () -> IO ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
instance EntropySource DevURandom where
entropyOpen :: IO (Maybe DevURandom)
entropyOpen = (DeviceName -> DevURandom) -> Maybe DeviceName -> Maybe DevURandom
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap DeviceName -> DevURandom
DevURandom (Maybe DeviceName -> Maybe DevURandom)
-> IO (Maybe DeviceName) -> IO (Maybe DevURandom)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` DeviceName -> IO (Maybe DeviceName)
testOpen DeviceName
"/dev/urandom"
entropyGather :: DevURandom -> Ptr Word8 -> Int -> IO Int
entropyGather (DevURandom DeviceName
name) Ptr Word8
ptr Int
n =
DeviceName -> (H -> IO Int) -> IO Int
forall a. DeviceName -> (H -> IO a) -> IO a
withDev DeviceName
name ((H -> IO Int) -> IO Int) -> (H -> IO Int) -> IO Int
forall a b. (a -> b) -> a -> b
$ \H
h -> H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropy H
h Ptr Word8
ptr Int
n
entropyClose :: DevURandom -> IO ()
entropyClose (DevURandom DeviceName
_) = () -> IO ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
testOpen :: DeviceName -> IO (Maybe DeviceName)
testOpen :: DeviceName -> IO (Maybe DeviceName)
testOpen DeviceName
filepath = do
Maybe H
d <- DeviceName -> IO (Maybe H)
openDev DeviceName
filepath
case Maybe H
d of
Maybe H
Nothing -> Maybe DeviceName -> IO (Maybe DeviceName)
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe DeviceName
forall a. Maybe a
Nothing
Just H
h -> H -> IO ()
closeDev H
h IO () -> IO (Maybe DeviceName) -> IO (Maybe DeviceName)
forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> Maybe DeviceName -> IO (Maybe DeviceName)
forall (m :: * -> *) a. Monad m => a -> m a
return (DeviceName -> Maybe DeviceName
forall a. a -> Maybe a
Just DeviceName
filepath)
openDev :: String -> IO (Maybe H)
openDev :: DeviceName -> IO (Maybe H)
openDev DeviceName
filepath = (H -> Maybe H
forall a. a -> Maybe a
Just (H -> Maybe H) -> IO H -> IO (Maybe H)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` IO H
openAndNoBuffering) IO (Maybe H) -> (IOException -> IO (Maybe H)) -> IO (Maybe H)
forall e a. Exception e => IO a -> (e -> IO a) -> IO a
`E.catch` \(IOException
_ :: IOException) -> Maybe H -> IO (Maybe H)
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe H
forall a. Maybe a
Nothing
where openAndNoBuffering :: IO H
openAndNoBuffering = do
H
h <- DeviceName -> IOMode -> IO H
openBinaryFile DeviceName
filepath IOMode
ReadMode
H -> BufferMode -> IO ()
hSetBuffering H
h BufferMode
NoBuffering
H -> IO H
forall (m :: * -> *) a. Monad m => a -> m a
return H
h
withDev :: String -> (H -> IO a) -> IO a
withDev :: DeviceName -> (H -> IO a) -> IO a
withDev DeviceName
filepath H -> IO a
f = DeviceName -> IO (Maybe H)
openDev DeviceName
filepath IO (Maybe H) -> (Maybe H -> IO a) -> IO a
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \Maybe H
h ->
case Maybe H
h of
Maybe H
Nothing -> DeviceName -> IO a
forall a. HasCallStack => DeviceName -> a
error (DeviceName
"device " DeviceName -> DeviceName -> DeviceName
forall a. [a] -> [a] -> [a]
++ DeviceName
filepath DeviceName -> DeviceName -> DeviceName
forall a. [a] -> [a] -> [a]
++ DeviceName
" cannot be grabbed")
Just H
fd -> H -> IO a
f H
fd IO a -> IO () -> IO a
forall a b. IO a -> IO b -> IO a
`E.finally` H -> IO ()
closeDev H
fd
closeDev :: H -> IO ()
closeDev :: H -> IO ()
closeDev H
h = H -> IO ()
hClose H
h
gatherDevEntropy :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropy :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropy H
h Ptr Word8
ptr Int
sz =
(Int -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Int -> Int) -> IO Int -> IO Int
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` H -> Ptr Word8 -> Int -> IO Int
forall a. H -> Ptr a -> Int -> IO Int
hGetBufSome H
h Ptr Word8
ptr (Int -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
sz))
IO Int -> (IOException -> IO Int) -> IO Int
forall e a. Exception e => IO a -> (e -> IO a) -> IO a
`E.catch` \(IOException
_ :: IOException) -> Int -> IO Int
forall (m :: * -> *) a. Monad m => a -> m a
return Int
0
gatherDevEntropyNonBlock :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropyNonBlock :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropyNonBlock H
h Ptr Word8
ptr Int
sz =
(Int -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Int -> Int) -> IO Int -> IO Int
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
`fmap` H -> Ptr Word8 -> Int -> IO Int
forall a. H -> Ptr a -> Int -> IO Int
hGetBufNonBlocking H
h Ptr Word8
ptr (Int -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
sz))
IO Int -> (IOException -> IO Int) -> IO Int
forall e a. Exception e => IO a -> (e -> IO a) -> IO a
`E.catch` \(IOException
_ :: IOException) -> Int -> IO Int
forall (m :: * -> *) a. Monad m => a -> m a
return Int
0