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|
{- git-annex assistant mount watcher, using either dbus or mtab polling
-
- Copyright 2012 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
module Assistant.Threads.MountWatcher where
import Assistant.Common
import Assistant.DaemonStatus
import Assistant.Sync
import qualified Annex
import qualified Git
import Utility.ThreadScheduler
import Utility.Mounts
import Remote.List
import qualified Types.Remote as Remote
import Assistant.Types.UrlRenderer
import Assistant.Fsck
import qualified Data.Set as S
#if WITH_DBUS
import Utility.DBus
import DBus.Client
import DBus
import Data.Word (Word32)
import Control.Concurrent
import qualified Control.Exception as E
#else
#ifdef linux_HOST_OS
#warning Building without dbus support; will use mtab polling
#endif
#endif
mountWatcherThread :: UrlRenderer -> NamedThread
mountWatcherThread urlrenderer = namedThread "MountWatcher" $
#if WITH_DBUS
dbusThread urlrenderer
#else
pollingThread urlrenderer
#endif
#if WITH_DBUS
dbusThread :: UrlRenderer -> Assistant ()
dbusThread urlrenderer = do
runclient <- asIO1 go
r <- liftIO $ E.try $ runClient getSystemAddress runclient
either onerr (const noop) r
where
go client = ifM (checkMountMonitor client)
( do
{- Store the current mount points in an MVar, to be
- compared later. We could in theory work out the
- mount point from the dbus message, but this is
- easier. -}
mvar <- liftIO $ newMVar =<< currentMountPoints
handleevent <- asIO1 $ \_event -> do
nowmounted <- liftIO $ currentMountPoints
wasmounted <- liftIO $ swapMVar mvar nowmounted
handleMounts urlrenderer wasmounted nowmounted
liftIO $ forM_ mountChanged $ \matcher ->
void $ addMatch client matcher handleevent
, do
liftAnnex $
warning "No known volume monitor available through dbus; falling back to mtab polling"
pollingThread urlrenderer
)
onerr :: E.SomeException -> Assistant ()
onerr e = do
liftAnnex $
warning $ "dbus failed; falling back to mtab polling (" ++ show e ++ ")"
pollingThread urlrenderer
{- Examine the list of services connected to dbus, to see if there
- are any we can use to monitor mounts. If not, will attempt to start one. -}
checkMountMonitor :: Client -> Assistant Bool
checkMountMonitor client = do
running <- filter (`elem` usableservices)
<$> liftIO (listServiceNames client)
case running of
[] -> startOneService client startableservices
(service:_) -> do
debug [ "Using running DBUS service"
, service
, "to monitor mount events."
]
return True
where
startableservices = [udisks2]
usableservices = startableservices
udisks2 = "org.freedesktop.UDisks2"
startOneService :: Client -> [ServiceName] -> Assistant Bool
startOneService _ [] = return False
startOneService client (x:xs) = do
_ <- liftIO $ tryNonAsync $ callDBus client "StartServiceByName"
[toVariant x, toVariant (0 :: Word32)]
ifM (liftIO $ elem x <$> listServiceNames client)
( do
debug
[ "Started DBUS service", x
, "to monitor mount events."
]
return True
, startOneService client xs
)
{- Filter matching events recieved when drives are mounted and unmounted. -}
mountChanged :: [MatchRule]
mountChanged = [udisks2mount, udisks2umount]
where
udisks2mount = matchAny
{ matchPath = Just "/org/freedesktop/UDisks2"
, matchInterface = Just "org.freedesktop.DBus.ObjectManager"
, matchMember = Just "InterfacesAdded"
}
udisks2umount = matchAny
{ matchPath = Just "/org/freedesktop/UDisks2"
, matchInterface = Just "org.freedesktop.DBus.ObjectManager"
, matchMember = Just "InterfacesRemoved"
}
#endif
pollingThread :: UrlRenderer -> Assistant ()
pollingThread urlrenderer = go =<< liftIO currentMountPoints
where
go wasmounted = do
liftIO $ threadDelaySeconds (Seconds 10)
nowmounted <- liftIO currentMountPoints
handleMounts urlrenderer wasmounted nowmounted
go nowmounted
handleMounts :: UrlRenderer -> MountPoints -> MountPoints -> Assistant ()
handleMounts urlrenderer wasmounted nowmounted =
mapM_ (handleMount urlrenderer . mnt_dir) $
S.toList $ newMountPoints wasmounted nowmounted
handleMount :: UrlRenderer -> FilePath -> Assistant ()
handleMount urlrenderer dir = do
debug ["detected mount of", dir]
rs <- filter (Git.repoIsLocal . Remote.repo) <$> remotesUnder dir
mapM_ (fsckNudge urlrenderer . Just) rs
reconnectRemotes True rs
{- Finds remotes located underneath the mount point.
-
- Updates state to include the remotes.
-
- The config of git remotes is re-read, as it may not have been available
- at startup time, or may have changed (it could even be a different
- repository at the same remote location..)
-}
remotesUnder :: FilePath -> Assistant [Remote]
remotesUnder dir = do
repotop <- liftAnnex $ fromRepo Git.repoPath
rs <- liftAnnex remoteList
pairs <- liftAnnex $ mapM (checkremote repotop) rs
let (waschanged, rs') = unzip pairs
when (or waschanged) $ do
liftAnnex $ Annex.changeState $ \s -> s { Annex.remotes = catMaybes rs' }
updateSyncRemotes
return $ mapMaybe snd $ filter fst pairs
where
checkremote repotop r = case Remote.localpath r of
Just p | dirContains dir (absPathFrom repotop p) ->
(,) <$> pure True <*> updateRemote r
_ -> return (False, Just r)
type MountPoints = S.Set Mntent
currentMountPoints :: IO MountPoints
currentMountPoints = S.fromList <$> getMounts
newMountPoints :: MountPoints -> MountPoints -> MountPoints
newMountPoints old new = S.difference new old
|
