3156febec8
The standalone build does not bundle its own ssh, so should be built to support as wide an array of ssh versions as possible, so turn off connection caching. Unfortunatly, as implemented this forces a full rebuild when building the standalone binary, and of course it makes it somewhat slower. This is not ideal, but neither is probing the ssh version every time it's run (slow), or once when initializing a repo (fragile).
145 lines
4.4 KiB
Haskell
145 lines
4.4 KiB
Haskell
{- git-annex ssh interface, with connection caching
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE CPP #-}
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module Annex.Ssh (
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sshParams,
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sshCleanup,
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) where
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import qualified Data.Map as M
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import Common.Annex
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import Annex.LockPool
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import qualified Git.Config
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import Config
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import qualified Build.SysConfig as SysConfig
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import Annex.Perms
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{- Generates parameters to ssh to a given host (or user@host) on a given
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- port, with connection caching. -}
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sshParams :: (String, Maybe Integer) -> [CommandParam] -> Annex [CommandParam]
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sshParams (host, port) opts = go =<< sshInfo (host, port)
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where
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go (Nothing, params) = ret params
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go (Just socketfile, params) = do
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cleanstale
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liftIO $ createDirectoryIfMissing True $ parentDir socketfile
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lockFile $ socket2lock socketfile
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ret params
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ret ps = return $ ps ++ opts ++ portParams port ++ [Param host]
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-- If the lock pool is empty, this is the first ssh of this
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-- run. There could be stale ssh connections hanging around
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-- from a previous git-annex run that was interrupted.
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cleanstale = whenM (not . any isLock . M.keys <$> getPool) $
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sshCleanup
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sshInfo :: (String, Maybe Integer) -> Annex (Maybe FilePath, [CommandParam])
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sshInfo (host, port) = ifM caching
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( do
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dir <- fromRepo gitAnnexSshDir
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let socketfile = dir </> hostport2socket host port
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if valid_unix_socket_path socketfile
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then return (Just socketfile, cacheParams socketfile)
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else do
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socketfile' <- liftIO $ relPathCwdToFile socketfile
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if valid_unix_socket_path socketfile'
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then return (Just socketfile', cacheParams socketfile')
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else return (Nothing, [])
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, return (Nothing, [])
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)
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where
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#ifdef WITH_OLD_SSH
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caching = return False
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#else
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caching = fromMaybe SysConfig.sshconnectioncaching
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. Git.Config.isTrue
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<$> getConfig (annexConfig "sshcaching") ""
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#endif
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cacheParams :: FilePath -> [CommandParam]
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cacheParams socketfile =
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[ Param "-S", Param socketfile
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, Params "-o ControlMaster=auto -o ControlPersist=yes"
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]
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portParams :: Maybe Integer -> [CommandParam]
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portParams Nothing = []
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portParams (Just port) = [Param "-p", Param $ show port]
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{- Stop any unused ssh processes. -}
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sshCleanup :: Annex ()
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sshCleanup = do
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dir <- fromRepo gitAnnexSshDir
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sockets <- filter (not . isLock) <$>
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liftIO (catchDefaultIO [] $ dirContents dir)
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forM_ sockets cleanup
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where
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cleanup socketfile = do
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-- Drop any shared lock we have, and take an
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-- exclusive lock, without blocking. If the lock
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-- succeeds, nothing is using this ssh, and it can
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-- be stopped.
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let lockfile = socket2lock socketfile
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unlockFile lockfile
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mode <- annexFileMode
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fd <- liftIO $ noUmask mode $
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openFd lockfile ReadWrite (Just mode) defaultFileFlags
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v <- liftIO $ tryIO $
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setLock fd (WriteLock, AbsoluteSeek, 0, 0)
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case v of
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Left _ -> noop
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Right _ -> stopssh socketfile
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liftIO $ closeFd fd
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stopssh socketfile = do
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let (host, port) = socket2hostport socketfile
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(_, params) <- sshInfo (host, port)
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void $ liftIO $ do
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-- "ssh -O stop" is noisy on stderr even with -q
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let cmd = unwords $ toCommand $
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[ Params "-O stop"
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] ++ params ++ [Param host]
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boolSystem "sh"
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[ Param "-c"
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, Param $ "ssh " ++ cmd ++ " >/dev/null 2>/dev/null"
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]
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-- Cannot remove the lock file; other processes may
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-- be waiting on our exclusive lock to use it.
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hostport2socket :: String -> Maybe Integer -> FilePath
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hostport2socket host Nothing = host
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hostport2socket host (Just port) = host ++ "!" ++ show port
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socket2hostport :: FilePath -> (String, Maybe Integer)
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socket2hostport socket
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| null p = (h, Nothing)
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| otherwise = (h, readish p)
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where
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(h, p) = separate (== '!') $ takeFileName socket
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socket2lock :: FilePath -> FilePath
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socket2lock socket = socket ++ lockExt
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isLock :: FilePath -> Bool
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isLock f = lockExt `isSuffixOf` f
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lockExt :: String
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lockExt = ".lock"
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{- This is the size of the sun_path component of sockaddr_un, which
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- is the limit to the total length of the filename of a unix socket.
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-
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- On Linux, this is 108. On OSX, 104. TODO: Probe
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-}
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sizeof_sockaddr_un_sun_path :: Int
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sizeof_sockaddr_un_sun_path = 100
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{- Note that this looks at the true length of the path in bytes, as it will
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- appear on disk. -}
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valid_unix_socket_path :: FilePath -> Bool
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valid_unix_socket_path f = length (decodeW8 f) < sizeof_sockaddr_un_sun_path
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