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Use non-blocking IO with /dev/random.

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Do not wait for data to appear from /dev/random, otherwise server is blocked
for a few seconds if there is no entropy left.
This commit is contained in:
Andrey Sverdlichenko 2015-06-29 07:32:42 +00:00
parent 75b362a2a0
commit 4581a737d7
1 changed files with 6 additions and 1 deletions
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7
Crypto/Random/Entropy/Unix.hs
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@ -31,7 +31,7 @@ newtype DevURandom = DevURandom DeviceName
instance EntropySource DevRandom where
entropyOpen = fmap DevRandom `fmap` testOpen "/dev/random"
entropyGather (DevRandom name) ptr n =
withDev name $ \h -> gatherDevEntropy h ptr n
withDev name $ \h -> gatherDevEntropyNonBlock h ptr n
entropyClose (DevRandom _) = return ()
instance EntropySource DevURandom where
@ -67,3 +67,8 @@ gatherDevEntropy :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropy h ptr sz =
(fromIntegral `fmap` hGetBufSome h ptr (fromIntegral sz))
`E.catch` \(_ :: IOException) -> return 0
gatherDevEntropyNonBlock :: H -> Ptr Word8 -> Int -> IO Int
gatherDevEntropyNonBlock h ptr sz =
(fromIntegral `fmap` hGetBufNonBlocking h ptr (fromIntegral sz))
`E.catch` \(_ :: IOException) -> return 0