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git-annex/P2P/Protocol.hs
Joey Hess b7454f1eeb
protocol version fallback on 404 
and prettified errors
2024-07-23 14:58:49 -04:00

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{- P2P protocol
-
- See doc/design/p2p_protocol.mdwn
-
- Copyright 2016-2024 Joey Hess <id@joeyh.name>
-
- 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
-- In order from newest to oldest.
allProtocolVersions :: [ProtocolVersion]
allProtocolVersions =
[ ProtocolVersion 3
, ProtocolVersion 2
, ProtocolVersion 1
, ProtocolVersion 0
]
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 ()
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