{-# OPTIONS_GHC -XFlexibleInstances -XTypeSynonymInstances -XStandaloneDeriving #-} {- Commands for HSH Copyright (C) 2004-2008 John Goerzen Please see the COPYRIGHT file -} {- | Module : HSH.Command Copyright : Copyright (C) 2006-2009 John Goerzen License : GNU LGPL, version 2.1 or above Maintainer : John Goerzen Stability : provisional Portability: portable Copyright (c) 2006-2009 John Goerzen, jgoerzen\@complete.org -} module HSH.Command (Environment, ShellCommand(..), PipeCommand(..), (-|-), RunResult, run, runIO, runSL, InvokeResult, checkResults, tryEC, catchEC, setenv, unsetenv ) where -- import System.IO.HVIO -- import System.IO.Utils import Prelude hiding (catch) import System.IO import System.Exit import System.Log.Logger import System.IO.Error (isUserError, ioeGetErrorString) import Data.Maybe.Utils import Data.Maybe import Data.List.Utils(uniq) import Control.Exception(try, evaluate, SomeException, catch) import Text.Regex.Posix import Control.Monad(when) import Data.String.Utils(rstrip) import Control.Concurrent import System.Process import System.Environment(getEnvironment) import qualified Data.ByteString.Lazy as BSL import qualified Data.ByteString as BS import HSH.Channel d, dr :: String -> IO () d = debugM "HSH.Command" dr = debugM "HSH.Command.Run" em = errorM "HSH.Command" {- | Result type for shell commands. The String is the text description of the command, not its output. -} type InvokeResult = (String, IO ExitCode) {- | Type for the environment. -} type Environment = Maybe [(String, String)] {- | A shell command is something we can invoke, pipe to, pipe from, or pipe in both directions. All commands that can be run as shell commands must define these methods. Minimum implementation is 'fdInvoke'. Some pre-defined instances include: * A simple bare string, which is passed to the shell for execution. The shell will then typically expand wildcards, parse parameters, etc. * A @(String, [String])@ tuple. The first item in the tuple gives the name of a program to run, and the second gives its arguments. The shell is never involved. This is ideal for passing filenames, since there is no security risk involving special shell characters. * A @Handle -> Handle -> IO ()@ function, which reads from the first handle and write to the second. * Various functions. These functions will accept input representing its standard input and output will go to standard output. Some pre-defined instance functions include: * @(String -> String)@, @(String -> IO String)@, plus the same definitions for ByteStrings. * @([String] -> [String])@, @([String] -> IO [String])@, where each @String@ in the list represents a single line * @(() -> String)@, @(() -> IO String)@, for commands that explicitly read no input. Useful with closures. Useful when you want to avoid reading stdin because something else already is. These have the unit as part of the function because otherwise we would have conflicts with things such as bare Strings, which represent a command name. -} class (Show a) => ShellCommand a where {- | Invoke a command. -} fdInvoke :: a -- ^ The command -> Environment -- ^ The environment -> Channel -- ^ Where to read input from -> IO (Channel, [InvokeResult]) -- ^ Returns an action that, when evaluated, waits for the process to finish and returns an exit code. instance Show (Handle -> Handle -> IO ()) where show _ = "(Handle -> Handle -> IO ())" instance Show (Channel -> IO Channel) where show _ = "(Channel -> IO Channel)" instance Show (String -> String) where show _ = "(String -> String)" instance Show (() -> String) where show _ = "(() -> String)" instance Show (String -> IO String) where show _ = "(String -> IO String)" instance Show (() -> IO String) where show _ = "(() -> IO String)" instance Show (BSL.ByteString -> BSL.ByteString) where show _ = "(Data.ByteString.Lazy.ByteString -> Data.ByteString.Lazy.ByteString)" instance Show (() -> BSL.ByteString) where show _ = "(() -> Data.ByteString.Lazy.ByteString)" instance Show (BSL.ByteString -> IO BSL.ByteString) where show _ = "(Data.ByteString.Lazy.ByteString -> IO Data.ByteString.Lazy.ByteString)" instance Show (() -> IO BSL.ByteString) where show _ = "(() -> IO BSL.ByteString)" instance Show (BS.ByteString -> BS.ByteString) where show _ = "(Data.ByteString.ByteString -> Data.ByteString.ByteString)" instance Show (() -> BS.ByteString) where show _ = "(() -> Data.ByteString.ByteString)" instance Show (BS.ByteString -> IO BS.ByteString) where show _ = "(Data.ByteString.ByteString -> IO Data.ByteString.ByteString)" instance Show (() -> IO BS.ByteString) where show _ = "(() -> IO Data.ByteString.ByteString)" instance ShellCommand (String -> IO String) where fdInvoke = genericStringlikeIO chanAsString {- | A user function that takes no input, and generates output. We will deal with it using hPutStr to send the output on. -} instance ShellCommand (() -> IO String) where fdInvoke = genericStringlikeO instance ShellCommand (BSL.ByteString -> IO BSL.ByteString) where fdInvoke = genericStringlikeIO chanAsBSL instance ShellCommand (() -> IO BSL.ByteString) where fdInvoke = genericStringlikeO instance ShellCommand (BS.ByteString -> IO BS.ByteString) where fdInvoke = genericStringlikeIO chanAsBS instance ShellCommand (() -> IO BS.ByteString) where fdInvoke = genericStringlikeO {- | An instance of 'ShellCommand' for a pure Haskell function mapping String to String. Implement in terms of (String -> IO String) for simplicity. -} instance ShellCommand (String -> String) where fdInvoke func = fdInvoke iofunc where iofunc :: String -> IO String iofunc = return . func instance ShellCommand (() -> String) where fdInvoke func = fdInvoke iofunc where iofunc :: () -> IO String iofunc = return . func instance ShellCommand (BSL.ByteString -> BSL.ByteString) where fdInvoke func = fdInvoke iofunc where iofunc :: BSL.ByteString -> IO BSL.ByteString iofunc = return . func instance ShellCommand (() -> BSL.ByteString) where fdInvoke func = fdInvoke iofunc where iofunc :: () -> IO BSL.ByteString iofunc = return . func instance ShellCommand (BS.ByteString -> BS.ByteString) where fdInvoke func = fdInvoke iofunc where iofunc :: BS.ByteString -> IO BS.ByteString iofunc = return . func instance ShellCommand (() -> BS.ByteString) where fdInvoke func = fdInvoke iofunc where iofunc :: () -> IO BS.ByteString iofunc = return . func instance ShellCommand (Channel -> IO Channel) where fdInvoke func _ cstdin = runInHandler (show func) (func cstdin) {- instance ShellCommand (Handle -> Handle -> IO ()) where fdInvoke func cstdin cstdout = runInHandler (show func) (func hstdin hstdout) -} genericStringlikeIO :: (Show (a -> IO a), Channelizable a) => (Channel -> IO a) -> (a -> IO a) -> Environment -> Channel -> IO (Channel, [InvokeResult]) genericStringlikeIO dechanfunc userfunc _ cstdin = do contents <- dechanfunc cstdin runInHandler (show userfunc) (realfunc contents) where realfunc contents = do r <- userfunc contents return (toChannel r) genericStringlikeO :: (Show (() -> IO a), Channelizable a) => (() -> IO a) -> Environment -> Channel -> IO (Channel, [InvokeResult]) genericStringlikeO userfunc _ _ = runInHandler (show userfunc) realfunc where realfunc :: IO Channel realfunc = do r <- userfunc () return (toChannel r) instance Show ([String] -> [String]) where show _ = "([String] -> [String])" instance Show (() -> [String]) where show _ = "(() -> [String])" instance Show ([String] -> IO [String]) where show _ = "([String] -> IO [String])" instance Show (() -> IO [String]) where show _ = "(() -> IO [String])" {- | An instance of 'ShellCommand' for a pure Haskell function mapping [String] to [String]. A [String] is generated from a Handle via the 'lines' function, and the reverse occurs via 'unlines'. So, this function is intended to operate upon lines of input and produce lines of output. -} instance ShellCommand ([String] -> [String]) where fdInvoke func = fdInvoke (unlines . func . lines) instance ShellCommand (() -> [String]) where fdInvoke func = fdInvoke (unlines . func) {- | The same for an IO function -} instance ShellCommand ([String] -> IO [String]) where fdInvoke func = fdInvoke iofunc where iofunc input = do r <- func (lines input) return (unlines r) instance ShellCommand (() -> IO [String]) where fdInvoke func = fdInvoke iofunc where iofunc :: (() -> IO String) iofunc () = do r <- func () return (unlines r) {- | An instance of 'ShellCommand' for an external command. The first String is the command to run, and the list of Strings represents the arguments to the program, if any. -} instance ShellCommand (String, [String]) where fdInvoke (fp, args) = genericCommand (RawCommand fp args) {- | An instance of 'ShellCommand' for an external command. The String is split using words to the command to run, and the arguments, if any. -} instance ShellCommand String where fdInvoke cmd = genericCommand (ShellCommand cmd) {- | How to we handle and external command. -} genericCommand :: CmdSpec -> Environment -> Channel -> IO (Channel, [InvokeResult]) -- Handling external command when stdin channel is a Handle genericCommand c environ (ChanHandle ih) = let cp = CreateProcess {cmdspec = c, cwd = Nothing, env = environ, std_in = UseHandle ih, std_out = CreatePipe, std_err = Inherit, close_fds = True #if MIN_VERSION_process(1,1,0) -- Or use GHC version as a proxy: __GLASGOW_HASKELL__ >= 720 -- Added field in process 1.1.0.0: , create_group = False #endif #if MIN_VERSION_process(1,2,0) , delegate_ctlc = False #endif #if MIN_VERSION_process(1,3,0) , detach_console = False , create_new_console = False , new_session = False #endif #if MIN_VERSION_process(1,4,0) , child_group = Nothing , child_user = Nothing #endif #if MIN_VERSION_process(1,5,0) , use_process_jobs = False #endif } in do (_, oh', _, ph) <- createProcess cp let oh = fromJust oh' return (ChanHandle oh, [(printCmdSpec c, waitForProcess ph)]) genericCommand cspec environ ichan = let cp = CreateProcess {cmdspec = cspec, cwd = Nothing, env = environ, std_in = CreatePipe, std_out = CreatePipe, std_err = Inherit, close_fds = True #if MIN_VERSION_process(1,1,0) -- Added field in process 1.1.0.0: , create_group = False #endif #if MIN_VERSION_process(1,2,0) , delegate_ctlc = False #endif #if MIN_VERSION_process(1,3,0) , detach_console = False , create_new_console = False , new_session = False #endif #if MIN_VERSION_process(1,4,0) , child_group = Nothing , child_user = Nothing #endif #if MIN_VERSION_process(1,5,0) , use_process_jobs = False #endif } in do (ih', oh', _, ph) <- createProcess cp let ih = fromJust ih' let oh = fromJust oh' chanToHandle True ichan ih return (ChanHandle oh, [(printCmdSpec cspec, waitForProcess ph)]) printCmdSpec :: CmdSpec -> String printCmdSpec (ShellCommand s) = s printCmdSpec (RawCommand fp args) = show (fp, args) ------------------------------------------------------------ -- Pipes ------------------------------------------------------------ data PipeCommand a b = (ShellCommand a, ShellCommand b) => PipeCommand a b deriving instance Show (PipeCommand a b) {- | An instance of 'ShellCommand' represeting a pipeline. -} instance (ShellCommand a, ShellCommand b) => ShellCommand (PipeCommand a b) where fdInvoke (PipeCommand cmd1 cmd2) env ichan = do (chan1, res1) <- fdInvoke cmd1 env ichan (chan2, res2) <- fdInvoke cmd2 env chan1 return (chan2, res1 ++ res2) {- | Pipe the output of the first command into the input of the second. -} (-|-) :: (ShellCommand a, ShellCommand b) => a -> b -> PipeCommand a b (-|-) = PipeCommand {- | Different ways to get data from 'run'. * IO () runs, throws an exception on error, and sends stdout to stdout * IO String runs, throws an exception on error, reads stdout into a buffer, and returns it as a string. Note: This output is not lazy. * IO [String] is same as IO String, but returns the results as lines. Note: this output is not lazy. * IO ExitCode runs and returns an ExitCode with the exit information. stdout is sent to stdout. Exceptions are not thrown. * IO (String, ExitCode) is like IO ExitCode, but also includes a description of the last command in the pipe to have an error (or the last command, if there was no error). * IO ByteString and are similar to their String counterparts. * IO (String, IO (String, ExitCode)) returns a String read lazily and an IO action that, when evaluated, finishes up the process and results in its exit status. This command returns immediately. * IO (IO (String, ExitCode)) sends stdout to stdout but returns immediately. It forks off the child but does not wait for it to finish. You can use 'checkResults' to wait for the finish. * IO Int returns the exit code from a program directly. If a signal caused the command to be reaped, returns 128 + SIGNUM. * IO Bool returns True if the program exited normally (exit code 0, not stopped by a signal) and False otherwise. To address insufficient laziness, you can process anything that needs to be processed lazily within the pipeline itself. -} class RunResult a where {- | Runs a command (or pipe of commands), with results presented in any number of different ways. -} run :: (ShellCommand b) => b -> a instance RunResult (IO ()) where run cmd = run cmd >>= checkResults instance RunResult (IO (String, ExitCode)) where run cmd = do (ochan, r) <- fdInvoke cmd Nothing (ChanHandle stdin) chanToHandle False ochan stdout processResults r instance RunResult (IO ExitCode) where run cmd = ((run cmd)::IO (String, ExitCode)) >>= return . snd instance RunResult (IO Int) where run cmd = do rc <- run cmd case rc of ExitSuccess -> return 0 ExitFailure x -> return x instance RunResult (IO Bool) where run cmd = do rc <- run cmd return ((rc::Int) == 0) instance RunResult (IO [String]) where run cmd = do r <- run cmd return (lines r) instance RunResult (IO String) where run cmd = genericStringlikeResult chanAsString (\c -> evaluate (length c)) cmd instance RunResult (IO BSL.ByteString) where run cmd = genericStringlikeResult chanAsBSL (\c -> evaluate (BSL.length c)) cmd instance RunResult (IO BS.ByteString) where run cmd = genericStringlikeResult chanAsBS (\c -> evaluate (BS.length c)) cmd instance RunResult (IO (String, IO (String, ExitCode))) where run cmd = intermediateStringlikeResult chanAsString cmd instance RunResult (IO (BSL.ByteString, IO (String, ExitCode))) where run cmd = intermediateStringlikeResult chanAsBSL cmd instance RunResult (IO (BS.ByteString, IO (String, ExitCode))) where run cmd = intermediateStringlikeResult chanAsBS cmd instance RunResult (IO (IO (String, ExitCode))) where run cmd = do (ochan, r) <- fdInvoke cmd Nothing (ChanHandle stdin) chanToHandle False ochan stdout return (processResults r) intermediateStringlikeResult :: ShellCommand b => (Channel -> IO a) -> b -> IO (a, IO (String, ExitCode)) intermediateStringlikeResult chanfunc cmd = do (ochan, r) <- fdInvoke cmd Nothing (ChanHandle stdin) c <- chanfunc ochan return (c, processResults r) genericStringlikeResult :: ShellCommand b => (Channel -> IO a) -> (a -> IO c) -> b -> IO a genericStringlikeResult chanfunc evalfunc cmd = do (c, r) <- intermediateStringlikeResult chanfunc cmd evalfunc c --evaluate (length c) -- d "runS 6" -- d "runS 7" r >>= checkResults -- d "runS 8" return c {- | Evaluates the result codes and returns an overall status -} processResults :: [InvokeResult] -> IO (String, ExitCode) processResults r = do rc <- mapM procresult r case catMaybes rc of [] -> return (fst (last r), ExitSuccess) x -> return (last x) where procresult :: InvokeResult -> IO (Maybe (String, ExitCode)) procresult (cmd, action) = do rc <- action return $ case rc of ExitSuccess -> Nothing x -> Just (cmd, x) {- | Evaluates result codes and raises an error for any bad ones it finds. -} checkResults :: (String, ExitCode) -> IO () checkResults (cmd, ps) = case ps of ExitSuccess -> return () ExitFailure x -> fail $ cmd ++ ": exited with code " ++ show x {- FIXME: generate these again Terminated sig -> fail $ cmd ++ ": terminated by signal " ++ show sig Stopped sig -> fail $ cmd ++ ": stopped by signal " ++ show sig -} {- | Handle an exception derived from a program exiting abnormally -} tryEC :: IO a -> IO (Either ExitCode a) tryEC action = do r <- Control.Exception.try action case r of Left ioe -> if isUserError ioe then case (ioeGetErrorString ioe =~~ pat) of Nothing -> ioError ioe -- not ours; re-raise it Just e -> return . Left . procit $ e else ioError ioe -- not ours; re-raise it Right result -> return (Right result) where pat = ": exited with code [0-9]+$|: terminated by signal ([0-9]+)$|: stopped by signal [0-9]+" procit :: String -> ExitCode procit e | e =~ "^: exited" = ExitFailure (str2ec e) -- | e =~ "^: terminated by signal" = Terminated (str2ec e) -- | e =~ "^: stopped by signal" = Stopped (str2ec e) | otherwise = error "Internal error in tryEC" str2ec e = read (e =~ "[0-9]+$") {- | Catch an exception derived from a program exiting abnormally -} catchEC :: IO a -> (ExitCode -> IO a) -> IO a catchEC action handler = do r <- tryEC action case r of Left ec -> handler ec Right result -> return result {- | A convenience function. Refers only to the version of 'run' that returns @IO ()@. This prevents you from having to cast to it all the time when you do not care about the result of 'run'. The implementation is simply: >runIO :: (ShellCommand a) => a -> IO () >runIO = run -} runIO :: (ShellCommand a) => a -> IO () runIO = run {- | Another convenience function. This returns the first line of the output, with any trailing newlines or whitespace stripped off. No leading whitespace is stripped. This function will raise an exception if there is not at least one line of output. Mnemonic: runSL means \"run single line\". This command exists separately from 'run' because there is already a 'run' instance that returns a String, though that instance returns the entirety of the output in that String. -} runSL :: (ShellCommand a) => a -> IO String runSL cmd = do r <- run cmd when (r == []) $ fail $ "runSL: no output received from " ++ show cmd return (rstrip . head $ r) {- | Convenience function to wrap a child thread. Kicks off the thread, handles running the code, traps execptions, the works. Note that if func is lazy, such as a getContents sort of thing, the exception may go uncaught here. NOTE: expects func to be lazy! -} runInHandler :: String -- ^ Description of this function -> (IO Channel) -- ^ The action to run in the thread -> IO (Channel, [InvokeResult]) runInHandler descrip func = catch (realfunc) (exchandler) where realfunc = do r <- func return (r, [(descrip, return ExitSuccess)]) exchandler :: SomeException -> IO (Channel, [InvokeResult]) exchandler e = do em $ "runInHandler/" ++ descrip ++ ": " ++ show e return (ChanString "", [(descrip, return (ExitFailure 1))]) ------------------------------------------------------------ -- Environment ------------------------------------------------------------ {- | An environment variable filter function. This is a low-level interface; see 'setenv' and 'unsetenv' for more convenient interfaces. -} type EnvironFilter = [(String, String)] -> [(String, String)] instance Show EnvironFilter where show _ = "EnvironFilter" {- | A command that carries environment variable information with it. This is a low-level interface; see 'setenv' and 'unsetenv' for more convenient interfaces. -} data EnvironCommand a = (ShellCommand a) => EnvironCommand EnvironFilter a deriving instance Show (EnvironCommand a) instance (ShellCommand a) => ShellCommand (EnvironCommand a) where fdInvoke (EnvironCommand efilter cmd) Nothing ichan = do -- No incoming environment; initialize from system default. e <- getEnvironment fdInvoke cmd (Just (efilter e)) ichan fdInvoke (EnvironCommand efilter cmd) (Just ienv) ichan = fdInvoke cmd (Just (efilter ienv)) ichan {- | Sets an environment variable, replacing an existing one if it exists. Here's a sample ghci session to illustrate. First, let's see the defaults for some variables: > Prelude HSH> runIO $ "echo $TERM, $LANG" > xterm, en_US.UTF-8 Now, let's set one: > Prelude HSH> runIO $ setenv [("TERM", "foo")] $ "echo $TERM, $LANG" > foo, en_US.UTF-8 Or two: > Prelude HSH> runIO $ setenv [("TERM", "foo")] $ setenv [("LANG", "de_DE.UTF-8")] $ "echo $TERM, $LANG" > foo, de_DE.UTF-8 We could also do it easier, like this: > Prelude HSH> runIO $ setenv [("TERM", "foo"), ("LANG", "de_DE.UTF-8")] $ "echo $TERM, $LANG" > foo, de_DE.UTF-8 It can be combined with unsetenv: > Prelude HSH> runIO $ setenv [("TERM", "foo")] $ unsetenv ["LANG"] $ "echo $TERM, $LANG" > foo, And used with pipes: > Prelude HSH> runIO $ setenv [("TERM", "foo")] $ "echo $TERM, $LANG" -|- "tr a-z A-Z" > FOO, EN_US.UTF-8 See also 'unsetenv'. -} setenv :: (ShellCommand cmd) => [(String, String)] -> cmd -> EnvironCommand cmd setenv items cmd = EnvironCommand efilter cmd where efilter ienv = foldr efilter' ienv items efilter' (key, val) ienv = (key, val) : (filter (\(k, _) -> k /= key) ienv) {- | Removes an environment variable if it exists; does nothing otherwise. See also 'setenv', which has a more extensive example. -} unsetenv :: (ShellCommand cmd) => [String] -> cmd -> EnvironCommand cmd unsetenv keys cmd = EnvironCommand efilter cmd where efilter ienv = foldr efilter' ienv keys efilter' key = filter (\(k, _) -> k /= key)