git-annex/P2P/IO.hs
Joey Hess a3b714ddd9
finish fixing removeLink on windows
9cb250f7be got the ones in RawFilePath,
but there were others that used the one from unix-compat, which fails at
runtime on windows. To avoid this,
import System.PosixCompat.Files hiding removeLink

This commit was sponsored by Ethan Aubin.
2020-11-24 13:20:44 -04:00

393 lines
11 KiB
Haskell

{- P2P protocol, IO implementation
-
- Copyright 2016-2018 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE RankNTypes, FlexibleContexts, CPP #-}
module P2P.IO
( RunProto
, RunState(..)
, mkRunState
, P2PConnection(..)
, ConnIdent(..)
, ClosableConnection(..)
, stdioP2PConnection
, connectPeer
, closeConnection
, serveUnixSocket
, setupHandle
, ProtoFailure(..)
, describeProtoFailure
, runNetProto
, runNet
) where
import Common
import P2P.Protocol
import P2P.Address
import Git
import Git.Command
import Utility.AuthToken
import Utility.SimpleProtocol
import Utility.Metered
import Utility.Tor
import Utility.FileMode
import Types.UUID
import Annex.ChangedRefs
import qualified Utility.RawFilePath as R
import Control.Monad.Free
import Control.Monad.IO.Class
import System.IO.Error
import Network.Socket
import Control.Concurrent
import Control.Concurrent.Async
import Control.Concurrent.STM
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L
import System.Log.Logger (debugM)
import qualified Network.Socket as S
-- Type of interpreters of the Proto free monad.
type RunProto m = forall a. Proto a -> m (Either ProtoFailure a)
data ProtoFailure
= ProtoFailureMessage String
| ProtoFailureException SomeException
| ProtoFailureIOError IOError
describeProtoFailure :: ProtoFailure -> String
describeProtoFailure (ProtoFailureMessage s) = s
describeProtoFailure (ProtoFailureException e) = show e
describeProtoFailure (ProtoFailureIOError e) = show e
data RunState
= Serving UUID (Maybe ChangedRefsHandle) (TVar ProtocolVersion)
| Client (TVar ProtocolVersion)
mkRunState :: (TVar ProtocolVersion -> RunState) -> IO RunState
mkRunState mk = do
tvar <- newTVarIO defaultProtocolVersion
return (mk tvar)
data P2PConnection = P2PConnection
{ connRepo :: Repo
, connCheckAuth :: (AuthToken -> Bool)
, connIhdl :: Handle
, connOhdl :: Handle
, connIdent :: ConnIdent
}
-- Identifier for a connection, only used for debugging.
newtype ConnIdent = ConnIdent (Maybe String)
data ClosableConnection conn
= OpenConnection conn
| ClosedConnection
-- P2PConnection using stdio.
stdioP2PConnection :: Git.Repo -> P2PConnection
stdioP2PConnection g = P2PConnection
{ connRepo = g
, connCheckAuth = const False
, connIhdl = stdin
, connOhdl = stdout
, connIdent = ConnIdent Nothing
}
-- Opens a connection to a peer. Does not authenticate with it.
connectPeer :: Git.Repo -> P2PAddress -> IO P2PConnection
connectPeer g (TorAnnex onionaddress onionport) = do
h <- setupHandle =<< connectHiddenService onionaddress onionport
return $ P2PConnection
{ connRepo = g
, connCheckAuth = const False
, connIhdl = h
, connOhdl = h
, connIdent = ConnIdent Nothing
}
closeConnection :: P2PConnection -> IO ()
closeConnection conn = do
hClose (connIhdl conn)
hClose (connOhdl conn)
-- Serves the protocol on a unix socket.
--
-- The callback is run to serve a connection, and is responsible for
-- closing the Handle when done.
--
-- Note that while the callback is running, other connections won't be
-- processed, so longterm work should be run in a separate thread by
-- the callback.
serveUnixSocket :: FilePath -> (Handle -> IO ()) -> IO ()
serveUnixSocket unixsocket serveconn = do
removeWhenExistsWith R.removeLink (toRawFilePath unixsocket)
soc <- S.socket S.AF_UNIX S.Stream S.defaultProtocol
S.bind soc (S.SockAddrUnix unixsocket)
-- Allow everyone to read and write to the socket,
-- so a daemon like tor, that is probably running as a different
-- de sock $ addModes
-- user, can access it.
--
-- Connections have to authenticate to do anything,
-- so it's fine that other local users can connect to the
-- socket.
modifyFileMode (toRawFilePath unixsocket) $ addModes
[groupReadMode, groupWriteMode, otherReadMode, otherWriteMode]
S.listen soc 2
forever $ do
(conn, _) <- S.accept soc
setupHandle conn >>= serveconn
setupHandle :: Socket -> IO Handle
setupHandle s = do
h <- socketToHandle s ReadWriteMode
hSetBuffering h LineBuffering
hSetBinaryMode h False
return h
-- Purposefully incomplete interpreter of Proto.
--
-- This only runs Net actions. No Local actions will be run
-- (those need the Annex monad) -- if the interpreter reaches any,
-- it returns Nothing.
runNetProto :: RunState -> P2PConnection -> Proto a -> IO (Either ProtoFailure a)
runNetProto runst conn = go
where
go :: RunProto IO
go (Pure v) = return (Right v)
go (Free (Net n)) = runNet runst conn go n
go (Free (Local _)) = return $ Left $
ProtoFailureMessage "unexpected annex operation attempted"
-- Interpreter of the Net part of Proto.
--
-- An interpreter of Proto has to be provided, to handle the rest of Proto
-- actions.
runNet :: (MonadIO m, MonadMask m) => RunState -> P2PConnection -> RunProto m -> NetF (Proto a) -> m (Either ProtoFailure a)
runNet runst conn runner f = case f of
SendMessage m next -> do
v <- liftIO $ tryNonAsync $ do
let l = unwords (formatMessage m)
debugMessage conn "P2P >" m
hPutStrLn (connOhdl conn) l
hFlush (connOhdl conn)
case v of
Left e -> return $ Left $ ProtoFailureException e
Right () -> runner next
ReceiveMessage next -> do
v <- liftIO $ tryIOError $ getProtocolLine (connIhdl conn)
case v of
Left e -> return $ Left $ ProtoFailureIOError e
Right Nothing -> return $ Left $
ProtoFailureMessage "protocol error"
Right (Just l) -> case parseMessage l of
Just m -> do
liftIO $ debugMessage conn "P2P <" m
runner (next (Just m))
Nothing -> runner (next Nothing)
SendBytes len b p next -> do
v <- liftIO $ tryNonAsync $ do
ok <- sendExactly len b (connOhdl conn) p
hFlush (connOhdl conn)
return ok
case v of
Right True -> runner next
Right False -> return $ Left $
ProtoFailureMessage "short data write"
Left e -> return $ Left $ ProtoFailureException e
ReceiveBytes len p next -> do
v <- liftIO $ tryNonAsync $ receiveExactly len (connIhdl conn) p
case v of
Left e -> return $ Left $ ProtoFailureException e
Right b -> runner (next b)
CheckAuthToken _u t next -> do
let authed = connCheckAuth conn t
runner (next authed)
Relay hin hout next -> do
v <- liftIO $ runRelay runnerio hin hout
case v of
Left e -> return $ Left e
Right exitcode -> runner (next exitcode)
RelayService service next -> do
v <- liftIO $ runRelayService conn runnerio service
case v of
Left e -> return $ Left e
Right () -> runner next
SetProtocolVersion v next -> do
liftIO $ atomically $ writeTVar versiontvar v
runner next
GetProtocolVersion next ->
liftIO (readTVarIO versiontvar) >>= runner . next
where
-- This is only used for running Net actions when relaying,
-- so it's ok to use runNetProto, despite it not supporting
-- all Proto actions.
runnerio = runNetProto runst conn
versiontvar = case runst of
Serving _ _ tv -> tv
Client tv -> tv
debugMessage :: P2PConnection -> String -> Message -> IO ()
debugMessage conn prefix m = do
tid <- myThreadId
debugM "p2p" $ concat $ catMaybes $
[ (\ident -> "[" ++ ident ++ "] ") <$> mident
, Just $ "[" ++ show tid ++ "] "
, Just $ prefix ++ " " ++ unwords (formatMessage safem)
]
where
safem = case m of
AUTH u _ -> AUTH u nullAuthToken
_ -> m
ConnIdent mident = connIdent conn
-- Send exactly the specified number of bytes or returns False.
--
-- The ByteString can be larger or smaller than the specified length.
-- For example, it can be lazily streaming from a file that gets
-- appended to, or truncated.
--
-- Must avoid sending too many bytes as it would confuse the other end.
-- This is easily dealt with by truncating it.
--
-- If too few bytes are sent, the only option is to give up on this
-- connection. False is returned to indicate this problem.
sendExactly :: Len -> L.ByteString -> Handle -> MeterUpdate -> IO Bool
sendExactly (Len n) b h p = do
sent <- meteredWrite' p h (L.take (fromIntegral n) b)
return (fromBytesProcessed sent == n)
receiveExactly :: Len -> Handle -> MeterUpdate -> IO L.ByteString
receiveExactly (Len n) h p = hGetMetered h (Just n) p
runRelay :: RunProto IO -> RelayHandle -> RelayHandle -> IO (Either ProtoFailure ExitCode)
runRelay runner (RelayHandle hout) (RelayHandle hin) =
bracket setup cleanup go
`catchNonAsync` (return . Left . ProtoFailureException)
where
setup = do
v <- newEmptyMVar
t1 <- async $ relayFeeder runner v hin
t2 <- async $ relayReader v hout
return (v, t1, t2)
cleanup (_, t1, t2) = do
hClose hin
hClose hout
cancel t1
cancel t2
go (v, _, _) = relayHelper runner v
runRelayService :: P2PConnection -> RunProto IO -> Service -> IO (Either ProtoFailure ())
runRelayService conn runner service =
withCreateProcess serviceproc' go
`catchNonAsync` (return . Left . ProtoFailureException)
where
cmd = case service of
UploadPack -> "upload-pack"
ReceivePack -> "receive-pack"
serviceproc = gitCreateProcess
[ Param cmd
, File (fromRawFilePath (repoPath (connRepo conn)))
] (connRepo conn)
serviceproc' = serviceproc
{ std_out = CreatePipe
, std_in = CreatePipe
}
go (Just hin) (Just hout) _ pid = do
v <- newEmptyMVar
r <- withAsync (relayFeeder runner v hin) $ \_ ->
withAsync (relayReader v hout) $ \_ ->
withAsync (waitexit v pid) $ \_ -> do
r <- runrelay v
hClose hin
hClose hout
return r
void $ waitForProcess pid
return r
go _ _ _ _ = error "internal"
runrelay v = relayHelper runner v >>= \case
Left e -> return $ Left e
Right 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 IO -> MVar RelayData -> IO (Either ProtoFailure ExitCode)
relayHelper runner v = loop
where
loop = do
d <- takeMVar v
case d of
RelayToPeer b -> do
r <- runner $ net $ relayToPeer (RelayToPeer b)
case r of
Left e -> return (Left e)
Right () -> loop
RelayDone exitcode -> do
_ <- runner $ net $ relayToPeer (RelayDone exitcode)
return (Right exitcode)
RelayFromPeer _ -> loop -- not handled here
-- Takes input from the peer, and sends it to the relay process's stdin.
-- Repeats until the peer tells it it's done or hangs up.
relayFeeder :: RunProto IO -> MVar RelayData -> Handle -> IO ()
relayFeeder runner v hin = loop
where
loop = do
mrd <- runner $ net relayFromPeer
case mrd of
Left _e ->
putMVar v (RelayDone (ExitFailure 1))
Right (RelayDone exitcode) ->
putMVar v (RelayDone exitcode)
Right (RelayFromPeer b) -> do
L.hPut hin b
hFlush hin
loop
Right (RelayToPeer _) -> loop -- not handled here
-- 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
-- Wait 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