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{- P2P protocol, partial IO implementation
-
- Copyright 2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE RankNTypes, CPP #-}
module P2P.IO
( RunProto
, runNetProtoHandle
) where
import Remote.Helper.P2P
import Utility.Process
import Git
import Git.Command
import Utility.SafeCommand
import Utility.SimpleProtocol
import Utility.Exception
import Control.Monad
import Control.Monad.Free
import Control.Monad.IO.Class
import System.Exit (ExitCode(..))
import System.IO
import Control.Concurrent
import Control.Concurrent.Async
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L
type RunProto = forall a m. (MonadIO m, MonadMask m) => Proto a -> m (Maybe a)
data S = S
{ repo :: Repo
, ihdl :: Handle
, ohdl :: Handle
}
-- Implementation of the protocol, communicating with a peer
-- over a Handle. No Local actions will be run.
runNetProtoHandle :: (MonadIO m, MonadMask m) => Handle -> Handle -> Repo -> Proto a -> m (Maybe a)
runNetProtoHandle i o r = go
where
go :: RunProto
go (Pure v) = pure (Just v)
go (Free (Net n)) = runNetHandle (S r i o) go n
go (Free (Local _)) = return Nothing
runNetHandle :: (MonadIO m, MonadMask m) => S -> RunProto -> NetF (Proto a) -> m (Maybe a)
runNetHandle s runner f = case f of
SendMessage m next -> do
v <- liftIO $ tryIO $ do
hPutStrLn (ohdl s) (unwords (formatMessage m))
hFlush (ohdl s)
case v of
Left _e -> return Nothing
Right () -> runner next
ReceiveMessage next -> do
v <- liftIO $ tryIO $ hGetLine (ihdl s)
case v of
Left _e -> return Nothing
Right l -> case parseMessage l of
Just m -> runner (next m)
Nothing -> runner $ do
let e = ERROR $ "protocol parse error: " ++ show l
net $ sendMessage e
next e
SendBytes _len b next -> do
v <- liftIO $ tryIO $ do
L.hPut (ohdl s) b
hFlush (ohdl s)
case v of
Left _e -> return Nothing
Right () -> runner next
ReceiveBytes (Len n) next -> do
v <- liftIO $ tryIO $ L.hGet (ihdl s) (fromIntegral n)
case v of
Left _e -> return Nothing
Right b -> runner (next b)
CheckAuthToken u t next -> do
authed <- return True -- TODO XXX FIXME really check
runner (next authed)
Relay hin hout next -> do
v <- liftIO $ runRelay runner hin hout
case v of
Nothing -> return Nothing
Just exitcode -> runner (next exitcode)
RelayService service next -> do
v <- liftIO $ runRelayService s runner service
case v of
Nothing -> return Nothing
Just () -> runner next
runRelay :: RunProto -> RelayHandle -> RelayHandle -> IO (Maybe ExitCode)
runRelay runner (RelayHandle hout) (RelayHandle hin) = bracket setup cleanup go
where
setup = do
v <- newEmptyMVar
void $ async $ relayFeeder runner v
void $ async $ relayReader v hout
return v
cleanup _ = do
hClose hin
hClose hout
go v = relayHelper runner v hin
runRelayService :: S -> RunProto -> Service -> IO (Maybe ())
runRelayService s runner service = bracket setup cleanup go
where
cmd = case service of
UploadPack -> "upload-pack"
ReceivePack -> "receive-pack"
serviceproc = gitCreateProcess
[ Param cmd
, File (repoPath (repo s))
] (repo s)
setup = do
(Just hin, Just hout, _, pid) <- createProcess serviceproc
{ std_out = CreatePipe
, std_in = CreatePipe
}
v <- newEmptyMVar
void $ async $ relayFeeder runner v
void $ async $ relayReader v hout
waiter <- async $ waitexit v pid
return (v, waiter, hin, hout, pid)
cleanup (_, waiter, hin, hout, pid) = do
hClose hin
hClose hout
cancel waiter
void $ waitForProcess pid
go (v, _, hin, _, _) = do
r <- relayHelper runner v hin
case r of
Nothing -> return Nothing
Just exitcode -> runner $ net $ relayToPeer (RelayDone exitcode)
waitexit v pid = putMVar v . RelayDone =<< waitForProcess pid
-- Processes RelayData as it is put into the MVar.
relayHelper :: RunProto -> MVar RelayData -> Handle -> IO (Maybe ExitCode)
relayHelper runner v hin = loop
where
loop = do
d <- takeMVar v
case d of
RelayFromPeer b -> do
L.hPut hin b
hFlush hin
loop
RelayToPeer b -> do
r <- runner $ net $ relayToPeer (RelayToPeer b)
case r of
Nothing -> return Nothing
Just () -> loop
RelayDone exitcode -> do
_ <- runner $ net $ relayToPeer (RelayDone exitcode)
return (Just exitcode)
-- Takes input from the peer, and puts it into the MVar for processing.
-- Repeats until the peer tells it it's done or hangs up.
relayFeeder :: RunProto -> MVar RelayData -> IO ()
relayFeeder runner v = loop
where
loop = do
mrd <- runner $ net relayFromPeer
case mrd of
Nothing -> putMVar v (RelayDone (ExitFailure 1))
Just rd -> do
putMVar v rd
case rd of
RelayDone _ -> return ()
_ -> loop
-- Reads input from the Handle and puts it into the MVar for relaying to
-- the peer. Continues until EOF on the Handle.
relayReader :: MVar RelayData -> Handle -> IO ()
relayReader v hout = loop
where
loop = do
bs <- getsome []
case bs of
[] -> return ()
_ -> do
putMVar v $ RelayToPeer (L.fromChunks bs)
loop
-- Waiit for the first available chunk. Then, without blocking,
-- try to get more chunks, in case a stream of chunks is being
-- written in close succession.
--
-- On Windows, hGetNonBlocking is broken, so avoid using it there.
getsome [] = do
b <- B.hGetSome hout chunk
if B.null b
then return []
#ifndef mingw32_HOST_OS
else getsome [b]
#else
else return [b]
#endif
getsome bs = do
b <- B.hGetNonBlocking hout chunk
if B.null b
then return (reverse bs)
else getsome (b:bs)
chunk = 65536
|