{- P2P protocol - - See doc/design/p2p_protocol.mdwn - - Copyright 2016-2024 Joey Hess - - Licensed under the GNU AGPL version 3 or higher. -} {-# LANGUAGE DeriveFunctor, TemplateHaskell, FlexibleContexts #-} {-# LANGUAGE TypeSynonymInstances, FlexibleInstances, RankNTypes #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {-# OPTIONS_GHC -fno-warn-orphans #-} module P2P.Protocol where import qualified Utility.SimpleProtocol as Proto import Types (Annex) import Types.Key import Types.UUID import Types.Transfer import Types.Remote (Verification(..)) import Utility.Hash (IncrementalVerifier(..)) import Utility.AuthToken import Utility.Applicative import Utility.PartialPrelude import Utility.Metered import Utility.FileSystemEncoding import Utility.MonotonicClock import Git.FilePath import Annex.ChangedRefs (ChangedRefs) import Types.NumCopies import Control.Monad import Control.Monad.Free import Control.Monad.Free.TH import Control.Monad.Catch import System.Exit (ExitCode(..)) import System.IO import qualified System.FilePath.ByteString as P import qualified Data.ByteString as B import qualified Data.ByteString.Lazy as L import qualified Data.Set as S import Data.Char import Data.Maybe import Data.Time.Clock.POSIX import Control.Applicative import Control.DeepSeq import Prelude newtype Offset = Offset Integer deriving (Show, Eq, NFData, Num, Real, Ord, Enum, Integral) newtype Len = Len Integer deriving (Show) newtype ProtocolVersion = ProtocolVersion Integer deriving (Show, Eq, Ord) defaultProtocolVersion :: ProtocolVersion defaultProtocolVersion = ProtocolVersion 0 maxProtocolVersion :: ProtocolVersion maxProtocolVersion = ProtocolVersion 3 newtype ProtoAssociatedFile = ProtoAssociatedFile AssociatedFile deriving (Show) -- | Service as used by the connect message in gitremote-helpers(1) data Service = UploadPack | ReceivePack deriving (Show) data Validity = Valid | Invalid deriving (Show) newtype Bypass = Bypass (S.Set UUID) deriving (Show, Monoid, Semigroup) -- | Messages in the protocol. The peer that makes the connection -- always initiates requests, and the other peer makes responses to them. data Message = AUTH UUID AuthToken -- uuid of the peer that is authenticating | AUTH_SUCCESS UUID -- uuid of the remote peer | AUTH_FAILURE | VERSION ProtocolVersion | CONNECT Service | CONNECTDONE ExitCode | NOTIFYCHANGE | CHANGED ChangedRefs | CHECKPRESENT Key | LOCKCONTENT Key | UNLOCKCONTENT | REMOVE Key | REMOVE_BEFORE MonotonicTimestamp Key | GETTIMESTAMP | GET Offset ProtoAssociatedFile Key | PUT ProtoAssociatedFile Key | PUT_FROM Offset | ALREADY_HAVE | ALREADY_HAVE_PLUS [UUID] | SUCCESS | SUCCESS_PLUS [UUID] | FAILURE | FAILURE_PLUS [UUID] | BYPASS Bypass | DATA Len -- followed by bytes of data | VALIDITY Validity | TIMESTAMP MonotonicTimestamp | ERROR String deriving (Show) instance Proto.Sendable Message where formatMessage (AUTH uuid authtoken) = ["AUTH", Proto.serialize uuid, Proto.serialize authtoken] formatMessage (AUTH_SUCCESS uuid) = ["AUTH-SUCCESS", Proto.serialize uuid] formatMessage AUTH_FAILURE = ["AUTH-FAILURE"] formatMessage (VERSION v) = ["VERSION", Proto.serialize v] formatMessage (CONNECT service) = ["CONNECT", Proto.serialize service] formatMessage (CONNECTDONE exitcode) = ["CONNECTDONE", Proto.serialize exitcode] formatMessage NOTIFYCHANGE = ["NOTIFYCHANGE"] formatMessage (CHANGED refs) = ["CHANGED", Proto.serialize refs] formatMessage (CHECKPRESENT key) = ["CHECKPRESENT", Proto.serialize key] formatMessage (LOCKCONTENT key) = ["LOCKCONTENT", Proto.serialize key] formatMessage UNLOCKCONTENT = ["UNLOCKCONTENT"] formatMessage (REMOVE key) = ["REMOVE", Proto.serialize key] formatMessage (REMOVE_BEFORE ts key) = ["REMOVE-BEFORE", Proto.serialize ts, Proto.serialize key] formatMessage GETTIMESTAMP = ["GETTIMESTAMP"] formatMessage (GET offset af key) = ["GET", Proto.serialize offset, Proto.serialize af, Proto.serialize key] formatMessage (PUT af key) = ["PUT", Proto.serialize af, Proto.serialize key] formatMessage (PUT_FROM offset) = ["PUT-FROM", Proto.serialize offset] formatMessage ALREADY_HAVE = ["ALREADY-HAVE"] formatMessage (ALREADY_HAVE_PLUS uuids) = ("ALREADY-HAVE-PLUS":map Proto.serialize uuids) formatMessage SUCCESS = ["SUCCESS"] formatMessage (SUCCESS_PLUS uuids) = ("SUCCESS-PLUS":map Proto.serialize uuids) formatMessage FAILURE = ["FAILURE"] formatMessage (FAILURE_PLUS uuids) = ("FAILURE-PLUS":map Proto.serialize uuids) formatMessage (BYPASS (Bypass uuids)) = ("BYPASS":map Proto.serialize (S.toList uuids)) formatMessage (DATA len) = ["DATA", Proto.serialize len] formatMessage (VALIDITY Valid) = ["VALID"] formatMessage (VALIDITY Invalid) = ["INVALID"] formatMessage (TIMESTAMP ts) = ["TIMESTAMP", Proto.serialize ts] formatMessage (ERROR err) = ["ERROR", Proto.serialize err] instance Proto.Receivable Message where parseCommand "AUTH" = Proto.parse2 AUTH parseCommand "AUTH-SUCCESS" = Proto.parse1 AUTH_SUCCESS parseCommand "AUTH-FAILURE" = Proto.parse0 AUTH_FAILURE parseCommand "VERSION" = Proto.parse1 VERSION parseCommand "CONNECT" = Proto.parse1 CONNECT parseCommand "CONNECTDONE" = Proto.parse1 CONNECTDONE parseCommand "NOTIFYCHANGE" = Proto.parse0 NOTIFYCHANGE parseCommand "CHANGED" = Proto.parse1 CHANGED parseCommand "CHECKPRESENT" = Proto.parse1 CHECKPRESENT parseCommand "LOCKCONTENT" = Proto.parse1 LOCKCONTENT parseCommand "UNLOCKCONTENT" = Proto.parse0 UNLOCKCONTENT parseCommand "REMOVE" = Proto.parse1 REMOVE parseCommand "REMOVE-BEFORE" = Proto.parse2 REMOVE_BEFORE parseCommand "GETTIMESTAMP" = Proto.parse0 GETTIMESTAMP parseCommand "GET" = Proto.parse3 GET parseCommand "PUT" = Proto.parse2 PUT parseCommand "PUT-FROM" = Proto.parse1 PUT_FROM parseCommand "ALREADY-HAVE" = Proto.parse0 ALREADY_HAVE parseCommand "ALREADY-HAVE-PLUS" = Proto.parseList ALREADY_HAVE_PLUS parseCommand "SUCCESS" = Proto.parse0 SUCCESS parseCommand "SUCCESS-PLUS" = Proto.parseList SUCCESS_PLUS parseCommand "FAILURE" = Proto.parse0 FAILURE parseCommand "FAILURE-PLUS" = Proto.parseList FAILURE_PLUS parseCommand "BYPASS" = Proto.parseList (BYPASS . Bypass . S.fromList) parseCommand "DATA" = Proto.parse1 DATA parseCommand "VALID" = Proto.parse0 (VALIDITY Valid) parseCommand "INVALID" = Proto.parse0 (VALIDITY Invalid) parseCommand "TIMESTAMP" = Proto.parse1 TIMESTAMP parseCommand "ERROR" = Proto.parse1 ERROR parseCommand _ = Proto.parseFail instance Proto.Serializable ProtocolVersion where serialize (ProtocolVersion n) = show n deserialize = ProtocolVersion <$$> readish instance Proto.Serializable Offset where serialize (Offset n) = show n deserialize = Offset <$$> readish instance Proto.Serializable Len where serialize (Len n) = show n deserialize = Len <$$> readish instance Proto.Serializable MonotonicTimestamp where serialize (MonotonicTimestamp n) = show n deserialize = MonotonicTimestamp <$$> readish instance Proto.Serializable Service where serialize UploadPack = "git-upload-pack" serialize ReceivePack = "git-receive-pack" deserialize "git-upload-pack" = Just UploadPack deserialize "git-receive-pack" = Just ReceivePack deserialize _ = Nothing -- | Since ProtoAssociatedFile is not the last thing in a protocol line, -- its serialization cannot contain any whitespace. This is handled -- by replacing whitespace with '%' (and '%' with '%%') -- -- When deserializing an AssociatedFile from a peer, that escaping is -- reversed. Unfortunately, an input tab will be deescaped to a space -- though. And it's sanitized, to avoid any control characters that might -- cause problems when it's displayed to the user. -- -- These mungings are ok, because a ProtoAssociatedFile is normally -- only displayed to the user and so does not need to match a file on disk. -- It may also be used in checking preferred content, which is very -- unlikely to care about spaces vs tabs or control characters. instance Proto.Serializable ProtoAssociatedFile where serialize (ProtoAssociatedFile (AssociatedFile Nothing)) = "" serialize (ProtoAssociatedFile (AssociatedFile (Just af))) = decodeBS $ toInternalGitPath $ encodeBS $ concatMap esc $ fromRawFilePath af where esc '%' = "%%" esc c | isSpace c = "%" | otherwise = [c] deserialize s = case fromInternalGitPath $ toRawFilePath $ deesc [] s of f | B.null f -> Just $ ProtoAssociatedFile $ AssociatedFile Nothing | P.isRelative f -> Just $ ProtoAssociatedFile $ AssociatedFile $ Just f | otherwise -> Nothing where deesc b [] = reverse b deesc b ('%':'%':cs) = deesc ('%':b) cs deesc b ('%':cs) = deesc ('_':b) cs deesc b (c:cs) | isControl c = deesc ('_':b) cs | otherwise = deesc (c:b) cs -- | Free monad for the protocol, combining net communication, -- and local actions. data ProtoF c = Net (NetF c) | Local (LocalF c) deriving (Functor) type Proto = Free ProtoF net :: Net a -> Proto a net = hoistFree Net local :: Local a -> Proto a local = hoistFree Local data NetF c = SendMessage Message c | ReceiveMessage (Maybe Message -> c) | SendBytes Len L.ByteString MeterUpdate c -- ^ Sends exactly Len bytes of data. (Any more or less will -- confuse the receiver.) | ReceiveBytes Len MeterUpdate (L.ByteString -> c) -- ^ Lazily reads bytes from peer. Stops once Len are read, -- or if connection is lost, and in either case returns the bytes -- that were read. This allows resuming interrupted transfers. | CheckAuthToken UUID AuthToken (Bool -> c) | RelayService Service c -- ^ Runs a service, relays its output to the peer, and data -- from the peer to it. | Relay RelayHandle RelayHandle (ExitCode -> c) -- ^ Reads from the first RelayHandle, and sends the data to a -- peer, while at the same time accepting input from the peer -- which is sent the the second RelayHandle. Continues until -- the peer sends an ExitCode. | SetProtocolVersion ProtocolVersion c --- ^ Called when a new protocol version has been negotiated. | GetProtocolVersion (ProtocolVersion -> c) | GetMonotonicTimestamp (MonotonicTimestamp -> c) deriving (Functor) type Net = Free NetF newtype RelayHandle = RelayHandle Handle data LocalF c = TmpContentSize Key (Len -> c) -- ^ Gets size of the temp file where received content may have -- been stored. If not present, returns 0. | FileSize FilePath (Len -> c) -- ^ Gets size of the content of a file. If not present, returns 0. | ContentSize Key (Maybe Len -> c) -- ^ Gets size of the content of a key, when the full content is -- present. | ReadContent Key AssociatedFile (Maybe FilePath) Offset (L.ByteString -> Proto Validity -> Proto (Maybe [UUID])) (Maybe [UUID] -> c) -- ^ Reads the content of a key and sends it to the callback. -- Must run the callback, or terminate the protocol connection. -- -- May send any amount of data, including L.empty if the content is -- not available. The callback must deal with that. -- -- And the content may change while it's being sent. -- The callback is passed a validity check that it can run after -- sending the content to detect when this happened. | StoreContent Key AssociatedFile Offset Len (Proto L.ByteString) (Proto (Maybe Validity)) (Bool -> c) -- ^ Stores content to the key's temp file starting at an offset. -- Once the whole content of the key has been stored, moves the -- temp file into place as the content of the key, and returns True. -- -- Must consume the whole lazy ByteString, or if unable to do -- so, terminate the protocol connection. -- -- If the validity check is provided and fails, the content was -- changed while it was being sent, so verification of the -- received content should be forced. -- -- Note: The ByteString may not contain the entire remaining content -- of the key. Only once the temp file size == Len has the whole -- content been transferred. | StoreContentTo FilePath (Maybe IncrementalVerifier) Offset Len (Proto L.ByteString) (Proto (Maybe Validity)) ((Bool, Verification) -> c) -- ^ Like StoreContent, but stores the content to a temp file. | SendContentWith (L.ByteString -> Annex (Maybe Validity -> Annex Bool)) (Proto L.ByteString) (Proto (Maybe Validity)) (Bool -> c) -- ^ Reads content from the Proto L.ByteString and sends it to the -- callback. The callback must consume the whole lazy ByteString, -- before it returns a validity checker. | SetPresent Key UUID c | CheckContentPresent Key (Bool -> c) -- ^ Checks if the whole content of the key is locally present. | RemoveContent Key (Maybe MonotonicTimestamp) (Bool -> c) -- ^ If the content is not present, still succeeds. -- May fail if not enough copies to safely drop, etc. -- After locking the content for removal, checks if it's later -- than the MonotonicTimestamp, and fails. | TryLockContent Key (Bool -> Proto ()) c -- ^ Try to lock the content of a key, preventing it -- from being deleted, while running the provided protocol -- action. If unable to lock the content, or the content is not -- present, runs the protocol action with False. | WaitRefChange (ChangedRefs -> c) -- ^ Waits for one or more git refs to change and returns them.a | UpdateMeterTotalSize Meter TotalSize c -- ^ Updates the total size of a Meter, for cases where the size is -- not known until the data is being received. | RunValidityCheck (Annex Validity) (Validity -> c) -- ^ Runs a deferred validity check. | GetLocalCurrentTime (POSIXTime -> c) -- ^ Gets the local time. deriving (Functor) type Local = Free LocalF -- Generate sendMessage etc functions for all free monad constructors. $(makeFree ''NetF) $(makeFree ''LocalF) auth :: UUID -> AuthToken -> Proto () -> Proto (Maybe UUID) auth myuuid t a = do net $ sendMessage (AUTH myuuid t) postAuth a postAuth :: Proto () -> Proto (Maybe UUID) postAuth a = do r <- net receiveMessage case r of Just (AUTH_SUCCESS theiruuid) -> do a return $ Just theiruuid Just AUTH_FAILURE -> return Nothing _ -> do net $ sendMessage (ERROR "auth failed") return Nothing negotiateProtocolVersion :: ProtocolVersion -> Proto () negotiateProtocolVersion preferredversion = do net $ sendMessage (VERSION preferredversion) r <- net receiveMessage case r of Just (VERSION v) -> net $ setProtocolVersion v -- Old server doesn't know about the VERSION command. Just (ERROR _) -> return () _ -> net $ sendMessage (ERROR "expected VERSION") sendBypass :: Bypass -> Proto () sendBypass bypass@(Bypass s) | S.null s = return () | otherwise = do ver <- net getProtocolVersion if ver >= ProtocolVersion 2 then net $ sendMessage (BYPASS bypass) else return () checkPresent :: Key -> Proto (Either String Bool) checkPresent key = do net $ sendMessage (CHECKPRESENT key) checkSuccess' {- Locks content to prevent it from being dropped, while running an action. - - Note that this only guarantees that the content is locked as long as the - connection to the peer remains up. If the connection is unexpectededly - dropped, the peer will then unlock the content. -} lockContentWhile :: MonadMask m => (forall r. r -> Proto r -> m r) -> Key -> (Bool -> m a) -> m a lockContentWhile runproto key a = bracket setup cleanup a where setup = runproto False $ do net $ sendMessage (LOCKCONTENT key) checkSuccess cleanup True = runproto () $ net $ sendMessage UNLOCKCONTENT cleanup False = return () remove :: Maybe SafeDropProof -> Key -> Proto (Either String Bool, Maybe [UUID]) remove proof key = case safeDropProofEndTime =<< proof of Nothing -> removeanytime Just endtime -> do ver <- net getProtocolVersion if ver >= ProtocolVersion 3 then removeBefore endtime key -- Peer is too old to support REMOVE-BEFORE else removeanytime where removeanytime = do net $ sendMessage (REMOVE key) checkSuccessFailurePlus getTimestamp :: Proto (Either String MonotonicTimestamp) getTimestamp = do net $ sendMessage GETTIMESTAMP net receiveMessage >>= \case Just (TIMESTAMP ts) -> return (Right ts) Just (ERROR err) -> return (Left err) _ -> do net $ sendMessage (ERROR "expected TIMESTAMP") return (Left "protocol error") {- The endtime is the last local time at which the key can be removed. - To tell the remote how long it has to remove the key, get its current - timestamp, and add to it the number of seconds from the current local - time until the endtime. - - Order of retrieving timestamps matters. Getting the local time after the - remote timestamp means that, if there is some delay in getting the - response from the remote, that is reflected in the local time, and so - reduces the allowed time. -} removeBefore :: POSIXTime -> Key -> Proto (Either String Bool, Maybe [UUID]) removeBefore endtime key = getTimestamp >>= \case Right remotetime -> do localtime <- local getLocalCurrentTime let timeleft = endtime - localtime let timeleft' = MonotonicTimestamp (floor timeleft) let remoteendtime = remotetime + timeleft' if timeleft <= 0 then return (Right False, Nothing) else removeBeforeRemoteEndTime remoteendtime key Left err -> return (Left err, Nothing) removeBeforeRemoteEndTime :: MonotonicTimestamp -> Key -> Proto (Either String Bool, Maybe [UUID]) removeBeforeRemoteEndTime remoteendtime key = do net $ sendMessage $ REMOVE_BEFORE remoteendtime key checkSuccessFailurePlus get :: FilePath -> Key -> Maybe IncrementalVerifier -> AssociatedFile -> Meter -> MeterUpdate -> Proto (Bool, Verification) get dest key iv af m p = receiveContent (Just m) p sizer storer $ \offset -> GET offset (ProtoAssociatedFile af) key where sizer = fileSize dest storer = storeContentTo dest iv put :: Key -> AssociatedFile -> MeterUpdate -> Proto (Maybe [UUID]) put key af p = put' key af $ \offset -> sendContent key af Nothing offset p put' :: Key -> AssociatedFile -> (Offset -> Proto (Maybe [UUID])) -> Proto (Maybe [UUID]) put' key af sender = do net $ sendMessage (PUT (ProtoAssociatedFile af) key) r <- net receiveMessage case r of Just (PUT_FROM offset) -> sender offset Just ALREADY_HAVE -> return (Just []) Just (ALREADY_HAVE_PLUS uuids) -> return (Just uuids) _ -> do net $ sendMessage (ERROR "expected PUT_FROM or ALREADY_HAVE") return Nothing -- The protocol does not have a way to get the PUT offset -- without sending DATA, so send an empty bytestring and indicate -- it is not valid. getPutOffset :: Key -> AssociatedFile -> Proto (Either [UUID] Offset) getPutOffset key af = do net $ sendMessage (PUT (ProtoAssociatedFile af) key) r <- net receiveMessage case r of Just (PUT_FROM offset) -> do void $ sendContent' nullMeterUpdate (Len 0) L.empty $ return Invalid return (Right offset) Just ALREADY_HAVE -> return (Left []) Just (ALREADY_HAVE_PLUS uuids) -> return (Left uuids) _ -> do net $ sendMessage (ERROR "expected PUT_FROM or ALREADY_HAVE") return (Left []) data ServerHandler a = ServerGot a | ServerContinue | ServerUnexpected -- Server loop, getting messages from the client and handling them serverLoop :: (Message -> Proto (ServerHandler a)) -> Proto (Maybe a) serverLoop a = serveOneMessage a serverLoop -- Get one message from the client and handle it. serveOneMessage :: (Message -> Proto (ServerHandler a)) -> ((Message -> Proto (ServerHandler a)) -> Proto (Maybe a)) -> Proto (Maybe a) serveOneMessage a cont = do mcmd <- net receiveMessage case mcmd of -- When the client sends ERROR to the server, the server -- gives up, since it's not clear what state the client -- is in, and so not possible to recover. Just (ERROR _) -> return Nothing -- When the client sends an unparsable message, the server -- responds with an error message, and continues. This allows -- expanding the protocol with new messages. Nothing -> do net $ sendMessage (ERROR "unknown command") cont a Just cmd -> do v <- a cmd case v of ServerGot r -> return (Just r) ServerContinue -> cont a -- If the client sends an unexpected message, -- the server will respond with ERROR, and -- always continues processing messages. -- -- Since the protocol is not versioned, this -- is necessary to handle protocol changes -- robustly, since the client can detect when -- it's talking to a server that does not -- support some new feature, and fall back. ServerUnexpected -> do net $ sendMessage (ERROR "unexpected command") cont a -- | Serve the protocol, with an unauthenticated peer. Once the peer -- successfully authenticates, returns their UUID. serveAuth :: UUID -> Proto (Maybe UUID) serveAuth myuuid = serverLoop handler where handler (AUTH theiruuid authtoken) = do ok <- net $ checkAuthToken theiruuid authtoken if ok then do net $ sendMessage (AUTH_SUCCESS myuuid) return (ServerGot theiruuid) else do net $ sendMessage AUTH_FAILURE return ServerContinue handler _ = return ServerUnexpected data ServerMode = ServeReadOnly -- ^ Allow reading, but not writing. | ServeAppendOnly -- ^ Allow reading, and storing new objects, but not deleting objects. | ServeReadWrite -- ^ Full read and write access. deriving (Show, Eq, Ord) -- | Serve the protocol, with a peer that has authenticated. serveAuthed :: ServerMode -> UUID -> Proto () serveAuthed servermode myuuid = void $ serverLoop $ serverHandler servermode myuuid -- | Serve a single command in the protocol, the same as serveAuthed, -- but without looping to handle the next command. serveOneCommandAuthed :: ServerMode -> UUID -> Proto () serveOneCommandAuthed servermode myuuid = fromMaybe () <$> serveOneMessage (serverHandler servermode myuuid) (const $ pure Nothing) serverHandler :: ServerMode -> UUID -> Message -> Proto (ServerHandler ()) serverHandler servermode myuuid = handler where handler (VERSION theirversion) = do let v = min theirversion maxProtocolVersion net $ setProtocolVersion v net $ sendMessage (VERSION v) return ServerContinue handler (LOCKCONTENT key) = do local $ tryLockContent key $ \locked -> do sendSuccess locked when locked $ do r' <- net receiveMessage case r' of Just UNLOCKCONTENT -> return () _ -> net $ sendMessage (ERROR "expected UNLOCKCONTENT") return ServerContinue handler (CHECKPRESENT key) = do sendSuccess =<< local (checkContentPresent key) return ServerContinue handler (REMOVE key) = handleremove key Nothing handler (REMOVE_BEFORE ts key) = handleremove key (Just ts) handler GETTIMESTAMP = do ts <- net getMonotonicTimestamp net $ sendMessage $ TIMESTAMP ts return ServerContinue handler (PUT (ProtoAssociatedFile af) key) = checkPUTServerMode servermode $ \case Nothing -> handleput af key Just notallowed -> do notallowed return ServerContinue handler (GET offset (ProtoAssociatedFile af) key) = do void $ sendContent key af Nothing offset nullMeterUpdate -- setPresent not called because the peer may have -- requested the data but not permanently stored it. return ServerContinue handler (CONNECT service) = do -- After connecting to git, there may be unconsumed data -- from the git processes hanging around (even if they -- exited successfully), so stop serving this connection. let endit = return $ ServerGot () checkCONNECTServerMode service servermode $ \case Nothing -> do net $ relayService service endit Just notallowed -> do notallowed endit handler NOTIFYCHANGE = do refs <- local waitRefChange net $ sendMessage (CHANGED refs) return ServerContinue handler (BYPASS _) = return ServerContinue handler _ = return ServerUnexpected handleput af key = do have <- local $ checkContentPresent key if have then net $ sendMessage ALREADY_HAVE else do let sizer = tmpContentSize key let storer = storeContent key af v <- receiveContent Nothing nullMeterUpdate sizer storer PUT_FROM when (observeBool v) $ local $ setPresent key myuuid return ServerContinue handleremove key mts = checkREMOVEServerMode servermode $ \case Nothing -> do sendSuccess =<< local (removeContent key mts) return ServerContinue Just notallowed -> do notallowed return ServerContinue sendReadOnlyError :: Proto () sendReadOnlyError = net $ sendMessage $ ERROR "this repository is read-only; write access denied" sendAppendOnlyError :: Proto () sendAppendOnlyError = net $ sendMessage $ ERROR "this repository is append-only; removal denied" checkPUTServerMode :: Monad m => ServerMode -> (Maybe (Proto ()) -> m a) -> m a checkPUTServerMode servermode a = case servermode of ServeReadWrite -> a Nothing ServeAppendOnly -> a Nothing ServeReadOnly -> a (Just sendReadOnlyError) checkREMOVEServerMode :: Monad m => ServerMode -> (Maybe (Proto ()) -> m a) -> m a checkREMOVEServerMode servermode a = case servermode of ServeReadWrite -> a Nothing ServeAppendOnly -> a (Just sendAppendOnlyError) ServeReadOnly -> a (Just sendReadOnlyError) checkCONNECTServerMode :: Monad m => Service -> ServerMode -> (Maybe (Proto ()) -> m a) -> m a checkCONNECTServerMode service servermode a = case (servermode, service) of (ServeReadWrite, _) -> a Nothing (ServeAppendOnly, UploadPack) -> a Nothing -- git protocol could be used to overwrite -- refs or something, so don't allow (ServeAppendOnly, ReceivePack) -> a (Just sendReadOnlyError) (ServeReadOnly, UploadPack) -> a Nothing (ServeReadOnly, ReceivePack) -> a (Just sendReadOnlyError) sendContent :: Key -> AssociatedFile -> Maybe FilePath -> Offset -> MeterUpdate -> Proto (Maybe [UUID]) sendContent key af o offset@(Offset n) p = go =<< local (contentSize key) where go (Just (Len totallen)) = do let len = totallen - n if len <= 0 then sender (Len 0) L.empty (return Valid) else local $ readContent key af o offset $ sender (Len len) -- Content not available to send. Indicate this by sending -- empty data and indicate it's invalid. go Nothing = sender (Len 0) L.empty (return Invalid) sender = sendContent' p' p' = offsetMeterUpdate p (toBytesProcessed n) sendContent' :: MeterUpdate -> Len -> L.ByteString -> Proto Validity -> Proto (Maybe [UUID]) sendContent' p len content validitycheck = do net $ sendMessage (DATA len) net $ sendBytes len content p ver <- net getProtocolVersion when (ver >= ProtocolVersion 1) $ net . sendMessage . VALIDITY =<< validitycheck checkSuccessPlus receiveContent :: Observable t => Maybe Meter -> MeterUpdate -> Local Len -> (Offset -> Len -> Proto L.ByteString -> Proto (Maybe Validity) -> Local t) -> (Offset -> Message) -> Proto t receiveContent mm p sizer storer mkmsg = do Len n <- local sizer let p' = offsetMeterUpdate p (toBytesProcessed n) let offset = Offset n net $ sendMessage (mkmsg offset) r <- net receiveMessage case r of Just (DATA len@(Len l)) -> do local $ case mm of Nothing -> return () Just m -> updateMeterTotalSize m (TotalSize (n+l)) ver <- net getProtocolVersion let validitycheck = if ver >= ProtocolVersion 1 then net receiveMessage >>= \case Just (VALIDITY v) -> return (Just v) _ -> do net $ sendMessage (ERROR "expected VALID or INVALID") return Nothing else return Nothing v <- local $ storer offset len (net (receiveBytes len p')) validitycheck sendSuccess (observeBool v) return v Just (ERROR _err) -> return observeFailure _ -> do net $ sendMessage (ERROR "expected DATA") return observeFailure checkSuccess :: Proto Bool checkSuccess = either (const False) id <$> checkSuccess' checkSuccess' :: Proto (Either String Bool) checkSuccess' = do ack <- net receiveMessage case ack of Just SUCCESS -> return (Right True) Just FAILURE -> return (Right False) Just (ERROR err) -> return (Left err) _ -> do net $ sendMessage (ERROR "expected SUCCESS or FAILURE") return (Right False) checkSuccessPlus :: Proto (Maybe [UUID]) checkSuccessPlus = checkSuccessFailurePlus >>= return . \case (Right True, v) -> v (Right False, _) -> Nothing (Left _, _) -> Nothing checkSuccessFailurePlus :: Proto (Either String Bool, Maybe [UUID]) checkSuccessFailurePlus = do ver <- net getProtocolVersion if ver >= ProtocolVersion 2 then do ack <- net receiveMessage case ack of Just SUCCESS -> return (Right True, Just []) Just (SUCCESS_PLUS l) -> return (Right True, Just l) Just FAILURE -> return (Right False, Nothing) Just (FAILURE_PLUS l) -> return (Right False, Just l) Just (ERROR err) -> return (Left err, Nothing) _ -> do net $ sendMessage (ERROR "expected SUCCESS or SUCCESS-PLUS or FAILURE or FAILURE-PLUS") return (Right False, Nothing) else do ok <- checkSuccess if ok then return (Right True, Just []) else return (Right False, Nothing) sendSuccess :: Bool -> Proto () sendSuccess True = net $ sendMessage SUCCESS sendSuccess False = net $ sendMessage FAILURE notifyChange :: Proto (Maybe ChangedRefs) notifyChange = do net $ sendMessage NOTIFYCHANGE ack <- net receiveMessage case ack of Just (CHANGED rs) -> return (Just rs) _ -> do net $ sendMessage (ERROR "expected CHANGED") return Nothing connect :: Service -> Handle -> Handle -> Proto ExitCode connect service hin hout = do net $ sendMessage (CONNECT service) net $ relay (RelayHandle hin) (RelayHandle hout) data RelayData = RelayToPeer L.ByteString | RelayFromPeer L.ByteString | RelayDone ExitCode deriving (Show) relayFromPeer :: Net RelayData relayFromPeer = do r <- receiveMessage case r of Just (CONNECTDONE exitcode) -> return $ RelayDone exitcode Just (DATA len) -> RelayFromPeer <$> receiveBytes len nullMeterUpdate _ -> do sendMessage $ ERROR "expected DATA or CONNECTDONE" return $ RelayDone $ ExitFailure 1 relayToPeer :: RelayData -> Net () relayToPeer (RelayDone exitcode) = sendMessage (CONNECTDONE exitcode) relayToPeer (RelayToPeer b) = do let len = Len $ fromIntegral $ L.length b sendMessage (DATA len) sendBytes len b nullMeterUpdate relayToPeer (RelayFromPeer _) = return ()