{-# LANGUAGE CPP, ForeignFunctionInterface #-} module Ssh ( copySSH, SSHCmd(..), runSSH, getSSH, environmentHelpSsh, environmentHelpScp, environmentHelpSshPort, remoteDarcs ) where import Prelude hiding ( lookup, catch ) import qualified Ratified( hGetContents ) import System.Exit ( ExitCode(..) ) import System.Environment ( getEnv ) #ifndef WIN32 import System.Posix.Process ( getProcessID ) #else import Darcs.Utils ( showHexLen ) import Data.Bits ( (.&.) ) import System.Random ( randomIO ) #endif import System.IO ( Handle, hSetBinaryMode, hPutStrLn, hGetLine, hFlush ) import System.IO.Unsafe ( unsafePerformIO ) import System.Directory ( doesFileExist, createDirectoryIfMissing ) import Control.Monad ( when ) import System.Process ( runInteractiveProcess ) import Data.Map ( Map, empty, insert, lookup ) import Data.IORef ( IORef, newIORef, readIORef, modifyIORef ) import Darcs.SignalHandler ( catchNonSignal ) import Darcs.Utils ( breakCommand, prettyException, catchall ) import Darcs.Global ( atexit, sshControlMasterDisabled, withDebugMode ) import Darcs.Lock ( tempdirLoc, removeFileMayNotExist ) import Darcs.URL (SshFilePath(..), urlOf) import Exec ( exec, Redirects, Redirect(..), ) import Progress ( withoutProgress, debugMessage, debugFail ) import Darcs.Flags( RemoteDarcs(..) ) import qualified Data.ByteString as B (ByteString, hGet, writeFile ) {-# NOINLINE sshConnections #-} sshConnections :: IORef (Map String (Maybe Connection)) sshConnections = unsafePerformIO $ newIORef empty data Connection = C { inp :: !Handle, out :: !Handle, err :: !Handle, deb :: String -> IO () } -- | @withSSHConnection rdarcs destination withconnection withoutconnection@ -- performs an action on a remote host. If we are already connected to @destination@, -- then it does @withconnection@, else @withoutconnection@. withSSHConnection :: String -> SshFilePath -> (Connection -> IO a) -> IO a -> IO a withSSHConnection rdarcs repoid withconnection withoutconnection = withoutProgress $ do cs <- readIORef sshConnections case lookup (urlOf repoid) (cs :: Map String (Maybe Connection)) of Just Nothing -> withoutconnection Just (Just c) -> withconnection c Nothing -> do mc <- do (ssh,sshargs_) <- getSSHOnly SSH let sshargs = sshargs_ ++ [sshUhost repoid, rdarcs, "transfer-mode","--repodir",sshRepo repoid] debugMessage $ "ssh "++unwords sshargs (i,o,e,_) <- runInteractiveProcess ssh sshargs Nothing Nothing hSetBinaryMode i True hSetBinaryMode o True l <- hGetLine o if l == "Hello user, I am darcs transfer mode" then return () else debugFail "Couldn't start darcs transfer-mode on server" let c = C { inp = i, out = o, err = e, deb = \s -> debugMessage ("with ssh (transfer-mode) "++sshUhost repoid++s) } modifyIORef sshConnections (insert (urlOf repoid) (Just c)) return $ Just c `catchNonSignal` \e -> do debugMessage $ "Failed to start ssh connection:\n "++ prettyException e severSSHConnection repoid debugMessage $ unlines $ [ "NOTE: the server may be running a version of darcs prior to 2.0.0." , "" , "Installing darcs 2 on the server will speed up ssh-based commands." ] return Nothing maybe withoutconnection withconnection mc severSSHConnection :: SshFilePath -> IO () severSSHConnection x = do debugMessage $ "Severing ssh failed connection to "++(sshUhost x) modifyIORef sshConnections (insert (urlOf x) Nothing) grabSSH :: SshFilePath -> Connection -> IO B.ByteString grabSSH dest c = do debugMessage $ "grabSSH dest=" ++ urlOf dest let failwith e = do severSSHConnection dest -- hGetContents is ok here because we're -- only grabbing stderr, and we're also -- about to throw the contents. eee <- Ratified.hGetContents (err c) debugFail $ e ++ " grabbing ssh file "++ urlOf dest++"/"++ file ++"\n"++eee file = sshFile dest deb c $ "get "++ file hPutStrLn (inp c) $ "get " ++ file hFlush (inp c) l2 <- hGetLine (out c) if l2 == "got "++file then do showlen <- hGetLine (out c) case reads showlen of [(len,"")] -> B.hGet (out c) len _ -> failwith "Couldn't get length" else if l2 == "error "++file then do e <- hGetLine (out c) case reads e of (msg,_):_ -> debugFail $ "Error reading file remotely:\n"++msg [] -> failwith "An error occurred" else failwith "Error" sshStdErrMode :: IO Redirect sshStdErrMode = withDebugMode $ \amdebugging -> return $ if amdebugging then AsIs else Null remoteDarcs :: RemoteDarcs -> String remoteDarcs DefaultRemoteDarcs = "darcs" remoteDarcs (RemoteDarcs x) = x copySSH :: RemoteDarcs -> SshFilePath -> FilePath -> IO () copySSH remote dest to | rdarcs <- remoteDarcs remote = do debugMessage $ "copySSH file: " ++ urlOf dest withSSHConnection rdarcs dest (\c -> grabSSH dest c >>= B.writeFile to) $ do let u = escape_dollar $ urlOf dest stderr_behavior <- sshStdErrMode r <- runSSH SCP dest [u,to] (AsIs,AsIs,stderr_behavior) when (r /= ExitSuccess) $ debugFail $ "(scp) failed to fetch: " ++ u where {- '$' in filenames is troublesome for scp, for some reason.. -} escape_dollar :: String -> String escape_dollar = concatMap tr where tr '$' = "\\$" tr c = [c] -- --------------------------------------------------------------------- -- older ssh helper functions -- --------------------------------------------------------------------- data SSHCmd = SSH | SCP | SFTP instance Show SSHCmd where show SSH = "ssh" show SCP = "scp" show SFTP = "sftp" runSSH :: SSHCmd -> SshFilePath -> [String] -> Redirects -> IO ExitCode runSSH cmd remoteAddr postArgs redirs = do (ssh, args) <- getSSH cmd remoteAddr exec ssh (args ++ [sshUhost remoteAddr] ++ postArgs) redirs -- | Return the command and arguments needed to run an ssh command -- along with any extra features like use of the control master. -- See 'getSSHOnly' getSSH :: SSHCmd -> SshFilePath -- ^ remote path -> IO (String, [String]) getSSH cmd remoteAddr = do (ssh, ssh_args) <- getSSHOnly cmd cm_args <- if sshControlMasterDisabled then return [] else do -- control master cmPath <- controlMasterPath remoteAddr hasLaunchedCm <- doesFileExist cmPath when (not hasLaunchedCm) $ launchSSHControlMaster remoteAddr hasCmFeature <- doesFileExist cmPath return $ if hasCmFeature then [ "-o ControlPath=" ++ cmPath ] else [] let verbosity = case cmd of SCP -> ["-q"] -- (p)scp is the only one that recognises -q -- sftp and (p)sftp do not, and plink neither _ -> [] -- return (ssh, verbosity ++ ssh_args ++ cm_args) -- | Return the command and arguments needed to run an ssh command. -- First try the appropriate darcs environment variable and SSH_PORT -- defaulting to "ssh" and no specified port. getSSHOnly :: SSHCmd -> IO (String, [String]) getSSHOnly cmd = do ssh_command <- getEnv (evar cmd) `catchall` return (show cmd) -- port port <- (portFlag cmd `fmap` getEnv "SSH_PORT") `catchall` return [] let (ssh, ssh_args) = breakCommand ssh_command -- return (ssh, ssh_args ++ port) where evar SSH = "DARCS_SSH" evar SCP = "DARCS_SCP" evar SFTP = "DARCS_SFTP" portFlag SSH x = ["-p", x] portFlag SCP x = ["-P", x] portFlag SFTP x = ["-oPort="++x] environmentHelpSsh :: ([String], [String]) environmentHelpSsh = (["DARCS_SSH"], [ "Repositories of the form [user@]host:[dir] are taken to be remote", "repositories, which Darcs accesses with the external program ssh(1).", "", "The environment variable $DARCS_SSH can be used to specify an", "alternative SSH client. Arguments may be included, separated by", "whitespace. The value is not interpreted by a shell, so shell", "constructs cannot be used; in particular, it is not possible for the", "program name to contain whitespace by using quoting or escaping."]) environmentHelpScp :: ([String], [String]) environmentHelpScp = (["DARCS_SCP", "DARCS_SFTP"], [ "When reading from a remote repository, Darcs will attempt to run", "`darcs transfer-mode' on the remote host. This will fail if the", "remote host only has Darcs 1 installed, doesn't have Darcs installed", "at all, or only allows SFTP.", "", "If transfer-mode fails, Darcs will fall back on scp(1) and sftp(1).", "The commands invoked can be customized with the environment variables", "$DARCS_SCP and $DARCS_SFTP respectively, which behave like $DARCS_SSH.", "If the remote end allows only sftp, try setting DARCS_SCP=sftp."]) environmentHelpSshPort :: ([String], [String]) environmentHelpSshPort = (["SSH_PORT"], [ "If this environment variable is set, it will be used as the port", "number for all SSH calls made by Darcs (when accessing remote", "repositories over SSH). This is useful if your SSH server does not", "run on the default port, and your SSH client does not support", "ssh_config(5). OpenSSH users will probably prefer to put something", "like `Host *.example.net Port 443' into their ~/.ssh/config file."]) -- | Return True if this version of ssh has a ControlMaster feature -- The ControlMaster functionality allows for ssh multiplexing hasSSHControlMaster :: IO Bool hasSSHControlMaster = do (ssh, _) <- getSSHOnly SSH -- If ssh has the ControlMaster feature, it will recognise the -- the -O flag, but exit with status 255 because of the nonsense -- command. If it does not have the feature, it will simply dump -- a help message on the screen and exit with 1. sx <- exec ssh ["-O", "an_invalid_command"] (Null,Null,Null) case sx of ExitFailure 255 -> return True _ -> return False -- | Launch an SSH control master in the background, if available. -- We don't have to wait for it or anything. -- Note also that this will cleanup after itself when darcs exits launchSSHControlMaster :: SshFilePath -> IO () launchSSHControlMaster dest = do hasMaster <- hasSSHControlMaster when hasMaster $ do (ssh, ssh_args) <- getSSHOnly SSH cmPath <- controlMasterPath dest removeFileMayNotExist cmPath -- -f : put ssh in the background once it succeeds in logging you in -- -M : launch as the control master for addr -- -N : don't run any commands -- -S : use cmPath as the ControlPath. Equivalent to -oControlPath= -- Warning: A do-notation statement discarded a result of type ExitCode. _ <- exec ssh (ssh_args ++ [sshUhost dest, "-S", cmPath, "-N", "-f", "-M"]) (Null,Null,AsIs) atexit $ exitSSHControlMaster dest return () -- | Tell the SSH control master for a given path to exit. exitSSHControlMaster :: SshFilePath -> IO () exitSSHControlMaster addr = do (ssh, ssh_args) <- getSSHOnly SSH cmPath <- controlMasterPath addr -- Warning: A do-notation statement discarded a result of type ExitCode. _ <- exec ssh (ssh_args ++ [sshUhost addr, "-S", cmPath, "-O", "exit"]) (Null,Null,Null) return () -- | Create the directory ssh control master path for a given address controlMasterPath :: SshFilePath -- ^ remote path (foo\@bar.com:file is ok; the file part with be stripped) -> IO FilePath controlMasterPath dest = do let addr = sshUhost dest tmp <- (fmap (/// ".darcs") $ getEnv "HOME") `catchall` tempdirLoc #ifdef WIN32 r <- randomIO let suffix = (showHexLen 6 (r .&. 0xFFFFFF :: Int)) #else suffix <- show `fmap` getProcessID #endif let tmpDarcsSsh = tmp /// "darcs-ssh" createDirectoryIfMissing True tmpDarcsSsh return $ tmpDarcsSsh /// addr ++ suffix (///) :: FilePath -> FilePath -> FilePath d /// f = d ++ "/" ++ f