{-# LANGUAGE CPP, ForeignFunctionInterface #-}
#if __GLASGOW_HASKELL__ >= 709
{-# LANGUAGE Safe #-}
#else
{-# LANGUAGE Trustworthy #-}
#endif
{-# LANGUAGE InterruptibleFFI #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  System.Process
-- Copyright   :  (c) The University of Glasgow 2004-2008
-- License     :  BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer  :  libraries@haskell.org
-- Stability   :  experimental
-- Portability :  non-portable (requires concurrency)
--
-- Operations for creating and interacting with sub-processes.
--
-----------------------------------------------------------------------------

-- TODO:
--      * Flag to control whether exiting the parent also kills the child.

module System.Process (
    -- * Running sub-processes
    createProcess,
    createProcess_,
    shell, proc,
    CreateProcess(..),
    CmdSpec(..),
    StdStream(..),
    ProcessHandle,

    -- ** Simpler functions for common tasks
    callProcess,
    callCommand,
    spawnProcess,
    spawnCommand,
    readCreateProcess,
    readProcess,
    readCreateProcessWithExitCode,
    readProcessWithExitCode,
    withCreateProcess,
    cleanupProcess,

    -- ** Related utilities
    showCommandForUser,
    Pid,
    getPid,
    getCurrentPid,

    -- ** Control-C handling on Unix
    -- $ctlc-handling

    -- * Process completion
    -- ** Notes about @exec@ on Windows
    -- $exec-on-windows
    waitForProcess,
    getProcessExitCode,
    terminateProcess,
    interruptProcessGroupOf,

    -- * Interprocess communication
    createPipe,
    createPipeFd,

    -- * Old deprecated functions
    -- | These functions pre-date 'createProcess' which is much more
    -- flexible.
    runProcess,
    runCommand,
    runInteractiveProcess,
    runInteractiveCommand,
    system,
    rawSystem,
    ) where

import Prelude hiding (mapM)

import System.Process.Internals

import Control.Concurrent
import Control.DeepSeq (rnf)
import Control.Exception (SomeException, mask, allowInterrupt, bracket, try, throwIO)
import qualified Control.Exception as C
import Control.Monad
import Data.Maybe
import Foreign
import Foreign.C
import System.Exit      ( ExitCode(..) )
import System.IO
import System.IO.Error (mkIOError, ioeSetErrorString)

#if defined(WINDOWS)
import System.Win32.Process (getProcessId, getCurrentProcessId, ProcessId)
#else
import System.Posix.Process (getProcessID)
import System.Posix.Types (CPid (..))
#endif

import GHC.IO.Exception ( ioException, IOErrorType(..), IOException(..) )

-- | The platform specific type for a process identifier.
--
-- This is always an integral type. Width and signedness are platform specific.
--
-- @since 1.6.3.0
#if defined(WINDOWS)
type Pid = ProcessId
#else
type Pid = CPid
#endif

-- ----------------------------------------------------------------------------
-- createProcess

-- | Construct a 'CreateProcess' record for passing to 'createProcess',
-- representing a raw command with arguments.
--
-- See 'RawCommand' for precise semantics of the specified @FilePath@.
proc :: FilePath -> [String] -> CreateProcess
proc :: String -> [String] -> CreateProcess
proc String
cmd [String]
args = CreateProcess { cmdspec :: CmdSpec
cmdspec = String -> [String] -> CmdSpec
RawCommand String
cmd [String]
args,
                                cwd :: Maybe String
cwd = forall a. Maybe a
Nothing,
                                env :: Maybe [(String, String)]
env = forall a. Maybe a
Nothing,
                                std_in :: StdStream
std_in = StdStream
Inherit,
                                std_out :: StdStream
std_out = StdStream
Inherit,
                                std_err :: StdStream
std_err = StdStream
Inherit,
                                close_fds :: Bool
close_fds = Bool
False,
                                create_group :: Bool
create_group = Bool
False,
                                delegate_ctlc :: Bool
delegate_ctlc = Bool
False,
                                detach_console :: Bool
detach_console = Bool
False,
                                create_new_console :: Bool
create_new_console = Bool
False,
                                new_session :: Bool
new_session = Bool
False,
                                child_group :: Maybe GroupID
child_group = forall a. Maybe a
Nothing,
                                child_user :: Maybe UserID
child_user = forall a. Maybe a
Nothing,
                                use_process_jobs :: Bool
use_process_jobs = Bool
False }

-- | Construct a 'CreateProcess' record for passing to 'createProcess',
-- representing a command to be passed to the shell.
shell :: String -> CreateProcess
shell :: String -> CreateProcess
shell String
str = CreateProcess { cmdspec :: CmdSpec
cmdspec = String -> CmdSpec
ShellCommand String
str,
                            cwd :: Maybe String
cwd = forall a. Maybe a
Nothing,
                            env :: Maybe [(String, String)]
env = forall a. Maybe a
Nothing,
                            std_in :: StdStream
std_in = StdStream
Inherit,
                            std_out :: StdStream
std_out = StdStream
Inherit,
                            std_err :: StdStream
std_err = StdStream
Inherit,
                            close_fds :: Bool
close_fds = Bool
False,
                            create_group :: Bool
create_group = Bool
False,
                            delegate_ctlc :: Bool
delegate_ctlc = Bool
False,
                            detach_console :: Bool
detach_console = Bool
False,
                            create_new_console :: Bool
create_new_console = Bool
False,
                            new_session :: Bool
new_session = Bool
False,
                            child_group :: Maybe GroupID
child_group = forall a. Maybe a
Nothing,
                            child_user :: Maybe UserID
child_user = forall a. Maybe a
Nothing,
                            use_process_jobs :: Bool
use_process_jobs = Bool
False }

{- |
This is the most general way to spawn an external process.  The
process can be a command line to be executed by a shell or a raw command
with a list of arguments.  The stdin, stdout, and stderr streams of
the new process may individually be attached to new pipes, to existing
'Handle's, or just inherited from the parent (the default.)

The details of how to create the process are passed in the
'CreateProcess' record.  To make it easier to construct a
'CreateProcess', the functions 'proc' and 'shell' are supplied that
fill in the fields with default values which can be overriden as
needed.

'createProcess' returns @(/mb_stdin_hdl/, /mb_stdout_hdl/, /mb_stderr_hdl/, /ph/)@,
where

 * if @'std_in' == 'CreatePipe'@, then @/mb_stdin_hdl/@ will be @Just /h/@,
   where @/h/@ is the write end of the pipe connected to the child
   process's @stdin@.

 * otherwise, @/mb_stdin_hdl/ == Nothing@

Similarly for @/mb_stdout_hdl/@ and @/mb_stderr_hdl/@.

For example, to execute a simple @ls@ command:

>   r <- createProcess (proc "ls" [])

To create a pipe from which to read the output of @ls@:

>   (_, Just hout, _, _) <-
>       createProcess (proc "ls" []){ std_out = CreatePipe }

To also set the directory in which to run @ls@:

>   (_, Just hout, _, _) <-
>       createProcess (proc "ls" []){ cwd = Just "/home/bob",
>                                     std_out = CreatePipe }

Note that @Handle@s provided for @std_in@, @std_out@, or @std_err@ via the
@UseHandle@ constructor will be closed by calling this function. This is not
always the desired behavior. In cases where you would like to leave the
@Handle@ open after spawning the child process, please use 'createProcess_'
instead. All created @Handle@s are initially in text mode; if you need them
to be in binary mode then use 'hSetBinaryMode'.

@/ph/@ contains a handle to the running process.  On Windows
'use_process_jobs' can be set in CreateProcess in order to create a
Win32 Job object to monitor a process tree's progress.  If it is set
then that job is also returned inside @/ph/@.  @/ph/@ can be used to
kill all running sub-processes.  This feature has been available since
1.5.0.0.

-}
createProcess
  :: CreateProcess
  -> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess :: CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess CreateProcess
cp = do
  (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
r <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"createProcess" CreateProcess
cp
  StdStream -> IO ()
maybeCloseStd (CreateProcess -> StdStream
std_in  CreateProcess
cp)
  StdStream -> IO ()
maybeCloseStd (CreateProcess -> StdStream
std_out CreateProcess
cp)
  StdStream -> IO ()
maybeCloseStd (CreateProcess -> StdStream
std_err CreateProcess
cp)
  forall (m :: * -> *) a. Monad m => a -> m a
return (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
r
 where
  maybeCloseStd :: StdStream -> IO ()
  maybeCloseStd :: StdStream -> IO ()
maybeCloseStd (UseHandle Handle
hdl)
    | Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stdin Bool -> Bool -> Bool
&& Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stdout Bool -> Bool -> Bool
&& Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stderr = Handle -> IO ()
hClose Handle
hdl
  maybeCloseStd StdStream
_ = forall (m :: * -> *) a. Monad m => a -> m a
return ()

-- | A 'C.bracket'-style resource handler for 'createProcess'.
--
-- Does automatic cleanup when the action finishes. If there is an exception
-- in the body then it ensures that the process gets terminated and any
-- 'CreatePipe' 'Handle's are closed. In particular this means that if the
-- Haskell thread is killed (e.g. 'killThread'), that the external process is
-- also terminated.
--
-- e.g.
--
-- > withCreateProcess (proc cmd args) { ... }  $ \stdin stdout stderr ph -> do
-- >   ...
--
-- @since 1.4.3.0
withCreateProcess
  :: CreateProcess
  -> (Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
  -> IO a
withCreateProcess :: forall a.
CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess CreateProcess
c Maybe Handle
-> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
action =
    forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
C.bracket (CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess CreateProcess
c) (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
cleanupProcess
              (\(Maybe Handle
m_in, Maybe Handle
m_out, Maybe Handle
m_err, ProcessHandle
ph) -> Maybe Handle
-> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
action Maybe Handle
m_in Maybe Handle
m_out Maybe Handle
m_err ProcessHandle
ph)

-- wrapper so we can get exceptions with the appropriate function name.
withCreateProcess_
  :: String
  -> CreateProcess
  -> (Maybe Handle -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
  -> IO a
withCreateProcess_ :: forall a.
String
-> CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess_ String
fun CreateProcess
c Maybe Handle
-> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
action =
    forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
C.bracketOnError (String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
fun CreateProcess
c) (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
cleanupProcess
                     (\(Maybe Handle
m_in, Maybe Handle
m_out, Maybe Handle
m_err, ProcessHandle
ph) -> Maybe Handle
-> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a
action Maybe Handle
m_in Maybe Handle
m_out Maybe Handle
m_err ProcessHandle
ph)

-- | Cleans up the process.
--
-- This function is meant to be invoked from any application level cleanup
-- handler. It terminates the process, and closes any 'CreatePipe' 'handle's.
--
-- @since 1.6.4.0
cleanupProcess :: (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
               -> IO ()
cleanupProcess :: (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO ()
cleanupProcess (Maybe Handle
mb_stdin, Maybe Handle
mb_stdout, Maybe Handle
mb_stderr,
                ph :: ProcessHandle
ph@(ProcessHandle MVar ProcessHandle__
_ Bool
delegating_ctlc MVar ()
_)) = do
    ProcessHandle -> IO ()
terminateProcess ProcessHandle
ph
    -- Note, it's important that other threads that might be reading/writing
    -- these handles also get killed off, since otherwise they might be holding
    -- the handle lock and prevent us from closing, leading to deadlock.
    forall b a. b -> (a -> b) -> Maybe a -> b
maybe (forall (m :: * -> *) a. Monad m => a -> m a
return ()) (IO () -> IO ()
ignoreSigPipe forall b c a. (b -> c) -> (a -> b) -> a -> c
. Handle -> IO ()
hClose) Maybe Handle
mb_stdin
    forall b a. b -> (a -> b) -> Maybe a -> b
maybe (forall (m :: * -> *) a. Monad m => a -> m a
return ()) Handle -> IO ()
hClose Maybe Handle
mb_stdout
    forall b a. b -> (a -> b) -> Maybe a -> b
maybe (forall (m :: * -> *) a. Monad m => a -> m a
return ()) Handle -> IO ()
hClose Maybe Handle
mb_stderr
    -- terminateProcess does not guarantee that it terminates the process.
    -- Indeed on Unix it's SIGTERM, which asks nicely but does not guarantee
    -- that it stops. If it doesn't stop, we don't want to hang, so we wait
    -- asynchronously using forkIO.

    -- However we want to end the Ctl-C handling synchronously, so we'll do
    -- that synchronously, and set delegating_ctlc as False for the
    -- waitForProcess (which would otherwise end the Ctl-C delegation itself).
    forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
delegating_ctlc
      IO ()
stopDelegateControlC
    ThreadId
_ <- IO () -> IO ThreadId
forkIO (ProcessHandle -> IO ExitCode
waitForProcess (ProcessHandle -> ProcessHandle
resetCtlcDelegation ProcessHandle
ph) forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> forall (m :: * -> *) a. Monad m => a -> m a
return ())
    forall (m :: * -> *) a. Monad m => a -> m a
return ()
  where
    resetCtlcDelegation :: ProcessHandle -> ProcessHandle
resetCtlcDelegation (ProcessHandle MVar ProcessHandle__
m Bool
_ MVar ()
l) = MVar ProcessHandle__ -> Bool -> MVar () -> ProcessHandle
ProcessHandle MVar ProcessHandle__
m Bool
False MVar ()
l

-- ----------------------------------------------------------------------------
-- spawnProcess/spawnCommand

-- | Creates a new process to run the specified raw command with the given
-- arguments. It does not wait for the program to finish, but returns the
-- 'ProcessHandle'.
--
-- @since 1.2.0.0
spawnProcess :: FilePath -> [String] -> IO ProcessHandle
spawnProcess :: String -> [String] -> IO ProcessHandle
spawnProcess String
cmd [String]
args = do
    (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
p) <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"spawnProcess" (String -> [String] -> CreateProcess
proc String
cmd [String]
args)
    forall (m :: * -> *) a. Monad m => a -> m a
return ProcessHandle
p

-- | Creates a new process to run the specified shell command.
-- It does not wait for the program to finish, but returns the 'ProcessHandle'.
--
-- @since 1.2.0.0
spawnCommand :: String -> IO ProcessHandle
spawnCommand :: String -> IO ProcessHandle
spawnCommand String
cmd = do
    (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
p) <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"spawnCommand" (String -> CreateProcess
shell String
cmd)
    forall (m :: * -> *) a. Monad m => a -> m a
return ProcessHandle
p


-- ----------------------------------------------------------------------------
-- callProcess/callCommand

-- | Creates a new process to run the specified command with the given
-- arguments, and wait for it to finish.  If the command returns a non-zero
-- exit code, an exception is raised.
--
-- If an asynchronous exception is thrown to the thread executing
-- @callProcess@, the forked process will be terminated and
-- @callProcess@ will wait (block) until the process has been
-- terminated.
--
-- @since 1.2.0.0
callProcess :: FilePath -> [String] -> IO ()
callProcess :: String -> [String] -> IO ()
callProcess String
cmd [String]
args = do
    ExitCode
exit_code <- forall a.
String
-> CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess_ String
"callProcess"
                   (String -> [String] -> CreateProcess
proc String
cmd [String]
args) { delegate_ctlc :: Bool
delegate_ctlc = Bool
True } forall a b. (a -> b) -> a -> b
$ \Maybe Handle
_ Maybe Handle
_ Maybe Handle
_ ProcessHandle
p ->
                   ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
p
    case ExitCode
exit_code of
      ExitCode
ExitSuccess   -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
      ExitFailure Int
r -> forall a. String -> String -> [String] -> Int -> IO a
processFailedException String
"callProcess" String
cmd [String]
args Int
r

-- | Creates a new process to run the specified shell command.  If the
-- command returns a non-zero exit code, an exception is raised.
--
-- If an asynchronous exception is thrown to the thread executing
-- @callCommand@, the forked process will be terminated and
-- @callCommand@ will wait (block) until the process has been
-- terminated.
--
-- @since 1.2.0.0
callCommand :: String -> IO ()
callCommand :: String -> IO ()
callCommand String
cmd = do
    ExitCode
exit_code <- forall a.
String
-> CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess_ String
"callCommand"
                   (String -> CreateProcess
shell String
cmd) { delegate_ctlc :: Bool
delegate_ctlc = Bool
True } forall a b. (a -> b) -> a -> b
$ \Maybe Handle
_ Maybe Handle
_ Maybe Handle
_ ProcessHandle
p ->
                   ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
p
    case ExitCode
exit_code of
      ExitCode
ExitSuccess   -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
      ExitFailure Int
r -> forall a. String -> String -> [String] -> Int -> IO a
processFailedException String
"callCommand" String
cmd [] Int
r

processFailedException :: String -> String -> [String] -> Int -> IO a
processFailedException :: forall a. String -> String -> [String] -> Int -> IO a
processFailedException String
fun String
cmd [String]
args Int
exit_code =
      forall a. IOException -> IO a
ioError (IOErrorType
-> String -> Maybe Handle -> Maybe String -> IOException
mkIOError IOErrorType
OtherError (String
fun forall a. [a] -> [a] -> [a]
++ String
": " forall a. [a] -> [a] -> [a]
++ String
cmd forall a. [a] -> [a] -> [a]
++
                                     forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap ((Char
' 'forall a. a -> [a] -> [a]
:) forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. Show a => a -> String
show) [String]
args forall a. [a] -> [a] -> [a]
++
                                     String
" (exit " forall a. [a] -> [a] -> [a]
++ forall a. Show a => a -> String
show Int
exit_code forall a. [a] -> [a] -> [a]
++ String
")")
                                 forall a. Maybe a
Nothing forall a. Maybe a
Nothing)


-- ----------------------------------------------------------------------------
-- Control-C handling on Unix

-- $ctlc-handling
--
-- When running an interactive console process (such as a shell, console-based
-- text editor or ghci), we typically want that process to be allowed to handle
-- Ctl-C keyboard interrupts how it sees fit. For example, while most programs
-- simply quit on a Ctl-C, some handle it specially. To allow this to happen,
-- use the @'delegate_ctlc' = True@ option in the 'CreateProcess' options.
--
-- The gory details:
--
-- By default Ctl-C will generate a @SIGINT@ signal, causing a 'UserInterrupt'
-- exception to be sent to the main Haskell thread of your program, which if
-- not specially handled will terminate the program. Normally, this is exactly
-- what is wanted: an orderly shutdown of the program in response to Ctl-C.
--
-- Of course when running another interactive program in the console then we
-- want to let that program handle Ctl-C. Under Unix however, Ctl-C sends
-- @SIGINT@ to every process using the console. The standard solution is that
-- while running an interactive program, ignore @SIGINT@ in the parent, and let
-- it be handled in the child process. If that process then terminates due to
-- the @SIGINT@ signal, then at that point treat it as if we had received the
-- @SIGINT@ ourselves and begin an orderly shutdown.
--
-- This behaviour is implemented by 'createProcess' (and
-- 'waitForProcess' \/ 'getProcessExitCode') when the @'delegate_ctlc' = True@
-- option is set. In particular, the @SIGINT@ signal will be ignored until
-- 'waitForProcess' returns (or 'getProcessExitCode' returns a non-Nothing
-- result), so it becomes especially important to use 'waitForProcess' for every
-- processes created.
--
-- In addition, in 'delegate_ctlc' mode, 'waitForProcess' and
-- 'getProcessExitCode' will throw a 'UserInterrupt' exception if the process
-- terminated with @'ExitFailure' (-SIGINT)@. Typically you will not want to
-- catch this exception, but let it propagate, giving a normal orderly shutdown.
-- One detail to be aware of is that the 'UserInterrupt' exception is thrown
-- /synchronously/ in the thread that calls 'waitForProcess', whereas normally
-- @SIGINT@ causes the exception to be thrown /asynchronously/ to the main
-- thread.
--
-- For even more detail on this topic, see
-- <http://www.cons.org/cracauer/sigint.html "Proper handling of SIGINT/SIGQUIT">.

-- $exec-on-windows
--
-- Note that processes which use the POSIX @exec@ system call (e.g. @gcc@)
-- require special care on Windows. Specifically, the @msvcrt@ C runtime used
-- frequently on Windows emulates @exec@ in a non-POSIX compliant manner, where
-- the caller will be terminated (with exit code 0) and execution will continue
-- in a new process. As a result, on Windows it will appear as though a child
-- process which has called @exec@ has terminated despite the fact that the
-- process would still be running on a POSIX-compliant platform.
--
-- Since many programs do use @exec@, the @process@ library exposes the
-- 'use_process_jobs' flag to make it possible to reliably detect when such a
-- process completes. When this flag is set a 'ProcessHandle' will not be
-- deemed to be \"finished\" until all processes spawned by it have
-- terminated (except those spawned by the child with the
-- @CREATE_BREAKAWAY_FROM_JOB@ @CreateProcess@ flag).
--
-- Note, however, that, because of platform limitations, the exit code returned
-- by @waitForProcess@ and @getProcessExitCode@ cannot not be relied upon when
-- the child uses @exec@, even when 'use_process_jobs' is used. Specifically,
-- these functions will return the exit code of the *original child* (which
-- always exits with code 0, since it called @exec@), not the exit code of the
-- process which carried on with execution after @exec@. This is different from
-- the behavior prescribed by POSIX but is the best approximation that can be
-- realised under the restrictions of the Windows process model.

-- -----------------------------------------------------------------------------

-- | @readProcess@ forks an external process, reads its standard output
-- strictly, blocking until the process terminates, and returns the output
-- string. The external process inherits the standard error.
--
-- If an asynchronous exception is thrown to the thread executing
-- @readProcess@, the forked process will be terminated and @readProcess@ will
-- wait (block) until the process has been terminated.
--
-- Output is returned strictly, so this is not suitable for launching processes
-- that require interaction over the standard file streams.
--
-- This function throws an 'IOError' if the process 'ExitCode' is
-- anything other than 'ExitSuccess'. If instead you want to get the
-- 'ExitCode' then use 'readProcessWithExitCode'.
--
-- Users of this function should compile with @-threaded@ if they
-- want other Haskell threads to keep running while waiting on
-- the result of readProcess.
--
-- >  > readProcess "date" [] []
-- >  "Thu Feb  7 10:03:39 PST 2008\n"
--
-- The arguments are:
--
-- * The command to run, which must be in the $PATH, or an absolute or relative path
--
-- * A list of separate command line arguments to the program
--
-- * A string to pass on standard input to the forked process.
--
readProcess
    :: FilePath                 -- ^ Filename of the executable (see 'RawCommand' for details)
    -> [String]                 -- ^ any arguments
    -> String                   -- ^ standard input
    -> IO String                -- ^ stdout
readProcess :: String -> [String] -> String -> IO String
readProcess String
cmd [String]
args = CreateProcess -> String -> IO String
readCreateProcess forall a b. (a -> b) -> a -> b
$ String -> [String] -> CreateProcess
proc String
cmd [String]
args

-- | @readCreateProcess@ works exactly like 'readProcess' except that it
-- lets you pass 'CreateProcess' giving better flexibility.
--
-- >  > readCreateProcess ((shell "pwd") { cwd = Just "/etc/" }) ""
-- >  "/etc\n"
--
-- Note that @Handle@s provided for @std_in@ or @std_out@ via the CreateProcess
-- record will be ignored.
--
-- @since 1.2.3.0

readCreateProcess
    :: CreateProcess
    -> String                   -- ^ standard input
    -> IO String                -- ^ stdout
readCreateProcess :: CreateProcess -> String -> IO String
readCreateProcess CreateProcess
cp String
input = do
    let cp_opts :: CreateProcess
cp_opts = CreateProcess
cp {
                    std_in :: StdStream
std_in  = StdStream
CreatePipe,
                    std_out :: StdStream
std_out = StdStream
CreatePipe
                  }
    (ExitCode
ex, String
output) <- forall a.
String
-> CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess_ String
"readCreateProcess" CreateProcess
cp_opts forall a b. (a -> b) -> a -> b
$
      \Maybe Handle
mb_inh Maybe Handle
mb_outh Maybe Handle
_ ProcessHandle
ph ->
        case (Maybe Handle
mb_inh, Maybe Handle
mb_outh) of
          (Just Handle
inh, Just Handle
outh) -> do

            -- fork off a thread to start consuming the output
            String
output  <- Handle -> IO String
hGetContents Handle
outh
            forall a. IO () -> (IO () -> IO a) -> IO a
withForkWait (forall a. a -> IO a
C.evaluate forall a b. (a -> b) -> a -> b
$ forall a. NFData a => a -> ()
rnf String
output) forall a b. (a -> b) -> a -> b
$ \IO ()
waitOut -> do

              -- now write any input
              forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless (forall (t :: * -> *) a. Foldable t => t a -> Bool
null String
input) forall a b. (a -> b) -> a -> b
$
                IO () -> IO ()
ignoreSigPipe forall a b. (a -> b) -> a -> b
$ Handle -> String -> IO ()
hPutStr Handle
inh String
input
              -- hClose performs implicit hFlush, and thus may trigger a SIGPIPE
              IO () -> IO ()
ignoreSigPipe forall a b. (a -> b) -> a -> b
$ Handle -> IO ()
hClose Handle
inh

              -- wait on the output
              IO ()
waitOut
              Handle -> IO ()
hClose Handle
outh

            -- wait on the process
            ExitCode
ex <- ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
ph
            forall (m :: * -> *) a. Monad m => a -> m a
return (ExitCode
ex, String
output)

          (Maybe Handle
Nothing,Maybe Handle
_) -> forall a. HasCallStack => String -> a
error String
"readCreateProcess: Failed to get a stdin handle."
          (Maybe Handle
_,Maybe Handle
Nothing) -> forall a. HasCallStack => String -> a
error String
"readCreateProcess: Failed to get a stdout handle."

    case ExitCode
ex of
     ExitCode
ExitSuccess   -> forall (m :: * -> *) a. Monad m => a -> m a
return String
output
     ExitFailure Int
r -> forall a. String -> String -> [String] -> Int -> IO a
processFailedException String
"readCreateProcess" String
cmd [String]
args Int
r
  where
    cmd :: String
cmd = case CreateProcess
cp of
            CreateProcess { cmdspec :: CreateProcess -> CmdSpec
cmdspec = ShellCommand String
sc } -> String
sc
            CreateProcess { cmdspec :: CreateProcess -> CmdSpec
cmdspec = RawCommand String
fp [String]
_ } -> String
fp
    args :: [String]
args = case CreateProcess
cp of
             CreateProcess { cmdspec :: CreateProcess -> CmdSpec
cmdspec = ShellCommand String
_ } -> []
             CreateProcess { cmdspec :: CreateProcess -> CmdSpec
cmdspec = RawCommand String
_ [String]
args' } -> [String]
args'


-- | @readProcessWithExitCode@ is like 'readProcess' but with two differences:
--
--  * it returns the 'ExitCode' of the process, and does not throw any
--    exception if the code is not 'ExitSuccess'.
--
--  * it reads and returns the output from process' standard error handle,
--    rather than the process inheriting the standard error handle.
--
-- On Unix systems, see 'waitForProcess' for the meaning of exit codes
-- when the process died as the result of a signal.
--
readProcessWithExitCode
    :: FilePath                 -- ^ Filename of the executable (see 'RawCommand' for details)
    -> [String]                 -- ^ any arguments
    -> String                   -- ^ standard input
    -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr
readProcessWithExitCode :: String -> [String] -> String -> IO (ExitCode, String, String)
readProcessWithExitCode String
cmd [String]
args =
    CreateProcess -> String -> IO (ExitCode, String, String)
readCreateProcessWithExitCode forall a b. (a -> b) -> a -> b
$ String -> [String] -> CreateProcess
proc String
cmd [String]
args

-- | @readCreateProcessWithExitCode@ works exactly like 'readProcessWithExitCode' except that it
-- lets you pass 'CreateProcess' giving better flexibility.
--
-- Note that @Handle@s provided for @std_in@, @std_out@, or @std_err@ via the CreateProcess
-- record will be ignored.
--
-- @since 1.2.3.0
readCreateProcessWithExitCode
    :: CreateProcess
    -> String                      -- ^ standard input
    -> IO (ExitCode,String,String) -- ^ exitcode, stdout, stderr
readCreateProcessWithExitCode :: CreateProcess -> String -> IO (ExitCode, String, String)
readCreateProcessWithExitCode CreateProcess
cp String
input = do
    let cp_opts :: CreateProcess
cp_opts = CreateProcess
cp {
                    std_in :: StdStream
std_in  = StdStream
CreatePipe,
                    std_out :: StdStream
std_out = StdStream
CreatePipe,
                    std_err :: StdStream
std_err = StdStream
CreatePipe
                  }
    forall a.
String
-> CreateProcess
-> (Maybe Handle
    -> Maybe Handle -> Maybe Handle -> ProcessHandle -> IO a)
-> IO a
withCreateProcess_ String
"readCreateProcessWithExitCode" CreateProcess
cp_opts forall a b. (a -> b) -> a -> b
$
      \Maybe Handle
mb_inh Maybe Handle
mb_outh Maybe Handle
mb_errh ProcessHandle
ph ->
        case (Maybe Handle
mb_inh, Maybe Handle
mb_outh, Maybe Handle
mb_errh) of
          (Just Handle
inh, Just Handle
outh, Just Handle
errh) -> do

            String
out <- Handle -> IO String
hGetContents Handle
outh
            String
err <- Handle -> IO String
hGetContents Handle
errh

            -- fork off threads to start consuming stdout & stderr
            forall a. IO () -> (IO () -> IO a) -> IO a
withForkWait  (forall a. a -> IO a
C.evaluate forall a b. (a -> b) -> a -> b
$ forall a. NFData a => a -> ()
rnf String
out) forall a b. (a -> b) -> a -> b
$ \IO ()
waitOut ->
             forall a. IO () -> (IO () -> IO a) -> IO a
withForkWait (forall a. a -> IO a
C.evaluate forall a b. (a -> b) -> a -> b
$ forall a. NFData a => a -> ()
rnf String
err) forall a b. (a -> b) -> a -> b
$ \IO ()
waitErr -> do

              -- now write any input
              forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless (forall (t :: * -> *) a. Foldable t => t a -> Bool
null String
input) forall a b. (a -> b) -> a -> b
$
                IO () -> IO ()
ignoreSigPipe forall a b. (a -> b) -> a -> b
$ Handle -> String -> IO ()
hPutStr Handle
inh String
input
              -- hClose performs implicit hFlush, and thus may trigger a SIGPIPE
              IO () -> IO ()
ignoreSigPipe forall a b. (a -> b) -> a -> b
$ Handle -> IO ()
hClose Handle
inh

              -- wait on the output
              IO ()
waitOut
              IO ()
waitErr

              Handle -> IO ()
hClose Handle
outh
              Handle -> IO ()
hClose Handle
errh

            -- wait on the process
            ExitCode
ex <- ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
ph
            forall (m :: * -> *) a. Monad m => a -> m a
return (ExitCode
ex, String
out, String
err)

          (Maybe Handle
Nothing,Maybe Handle
_,Maybe Handle
_) -> forall a. HasCallStack => String -> a
error String
"readCreateProcessWithExitCode: Failed to get a stdin handle."
          (Maybe Handle
_,Maybe Handle
Nothing,Maybe Handle
_) -> forall a. HasCallStack => String -> a
error String
"readCreateProcessWithExitCode: Failed to get a stdout handle."
          (Maybe Handle
_,Maybe Handle
_,Maybe Handle
Nothing) -> forall a. HasCallStack => String -> a
error String
"readCreateProcessWithExitCode: Failed to get a stderr handle."

-- | Fork a thread while doing something else, but kill it if there's an
-- exception.
--
-- This is important in the cases above because we want to kill the thread
-- that is holding the Handle lock, because when we clean up the process we
-- try to close that handle, which could otherwise deadlock.
--
withForkWait :: IO () -> (IO () ->  IO a) -> IO a
withForkWait :: forall a. IO () -> (IO () -> IO a) -> IO a
withForkWait IO ()
async IO () -> IO a
body = do
  MVar (Either SomeException ())
waitVar <- forall a. IO (MVar a)
newEmptyMVar :: IO (MVar (Either SomeException ()))
  forall b. ((forall a. IO a -> IO a) -> IO b) -> IO b
mask forall a b. (a -> b) -> a -> b
$ \forall a. IO a -> IO a
restore -> do
    ThreadId
tid <- IO () -> IO ThreadId
forkIO forall a b. (a -> b) -> a -> b
$ forall e a. Exception e => IO a -> IO (Either e a)
try (forall a. IO a -> IO a
restore IO ()
async) forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= forall a. MVar a -> a -> IO ()
putMVar MVar (Either SomeException ())
waitVar
    let wait :: IO ()
wait = forall a. MVar a -> IO a
takeMVar MVar (Either SomeException ())
waitVar forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
either forall e a. Exception e => e -> IO a
throwIO forall (m :: * -> *) a. Monad m => a -> m a
return
    forall a. IO a -> IO a
restore (IO () -> IO a
body IO ()
wait) forall a b. IO a -> IO b -> IO a
`C.onException` ThreadId -> IO ()
killThread ThreadId
tid

ignoreSigPipe :: IO () -> IO ()
ignoreSigPipe :: IO () -> IO ()
ignoreSigPipe = forall e a. Exception e => (e -> IO a) -> IO a -> IO a
C.handle forall a b. (a -> b) -> a -> b
$ \IOException
e -> case IOException
e of
                                   IOError { ioe_type :: IOException -> IOErrorType
ioe_type  = IOErrorType
ResourceVanished
                                           , ioe_errno :: IOException -> Maybe CInt
ioe_errno = Just CInt
ioe }
                                     | CInt -> Errno
Errno CInt
ioe forall a. Eq a => a -> a -> Bool
== Errno
ePIPE -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
                                   IOException
_ -> forall e a. Exception e => e -> IO a
throwIO IOException
e

-- ----------------------------------------------------------------------------
-- showCommandForUser

-- | Given a program @/p/@ and arguments @/args/@,
--   @showCommandForUser /p/ /args/@ returns a string suitable for pasting
--   into @\/bin\/sh@ (on Unix systems) or @CMD.EXE@ (on Windows).
showCommandForUser :: FilePath -> [String] -> String
showCommandForUser :: String -> [String] -> String
showCommandForUser String
cmd [String]
args = [String] -> String
unwords (forall a b. (a -> b) -> [a] -> [b]
map String -> String
translate (String
cmd forall a. a -> [a] -> [a]
: [String]
args))


-- ----------------------------------------------------------------------------
-- getPid

-- | Returns the PID (process ID) of a subprocess.
--
-- 'Nothing' is returned if the handle was already closed. Otherwise a
-- PID is returned that remains valid as long as the handle is open.
-- The operating system may reuse the PID as soon as the last handle to
-- the process is closed.
--
-- @since 1.6.3.0
getPid :: ProcessHandle -> IO (Maybe Pid)
getPid :: ProcessHandle -> IO (Maybe Pid)
getPid (ProcessHandle MVar ProcessHandle__
mh Bool
_ MVar ()
_) = do
  ProcessHandle__
p_ <- forall a. MVar a -> IO a
readMVar MVar ProcessHandle__
mh
  case ProcessHandle__
p_ of
#ifdef WINDOWS
    OpenHandle h -> do
      pid <- getProcessId h
      return $ Just pid
#else
    OpenHandle Pid
pid -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a. a -> Maybe a
Just Pid
pid
#endif
    ProcessHandle__
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing


-- ----------------------------------------------------------------------------
-- getCurrentPid

-- | Returns the PID (process ID) of the current process. On POSIX systems,
-- this calls 'getProcessID' from "System.Posix.Process" in the @unix@ package.
-- On Windows, this calls 'getCurrentProcessId' from "System.Win32.Process" in
-- the @Win32@ package.
--
-- @since 1.6.12.0
getCurrentPid :: IO Pid
getCurrentPid :: IO Pid
getCurrentPid =
#ifdef WINDOWS
    getCurrentProcessId
#else
    IO Pid
getProcessID
#endif


-- ----------------------------------------------------------------------------
-- waitForProcess

{- | Waits for the specified process to terminate, and returns its exit code.
On Unix systems, may throw 'UserInterrupt' when using 'delegate_ctlc'.

GHC Note: in order to call @waitForProcess@ without blocking all the
other threads in the system, you must compile the program with
@-threaded@.

Note that it is safe to call @waitForProcess@ for the same process in multiple
threads. When the process ends, threads blocking on this call will wake in
FIFO order. When using 'delegate_ctlc' and the process is interrupted, only
the first waiting thread will throw 'UserInterrupt'.

(/Since: 1.2.0.0/) On Unix systems, a negative value @'ExitFailure' -/signum/@
indicates that the child was terminated by signal @/signum/@.
The signal numbers are platform-specific, so to test for a specific signal use
the constants provided by "System.Posix.Signals" in the @unix@ package.
Note: core dumps are not reported, use "System.Posix.Process" if you need this
detail.

-}
waitForProcess
  :: ProcessHandle
  -> IO ExitCode
waitForProcess :: ProcessHandle -> IO ExitCode
waitForProcess ph :: ProcessHandle
ph@(ProcessHandle MVar ProcessHandle__
_ Bool
delegating_ctlc MVar ()
_) = forall a. IO a -> IO a
lockWaitpid forall a b. (a -> b) -> a -> b
$ do
  ProcessHandle__
p_ <- forall a.
ProcessHandle
-> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
modifyProcessHandle ProcessHandle
ph forall a b. (a -> b) -> a -> b
$ \ProcessHandle__
p_ -> forall (m :: * -> *) a. Monad m => a -> m a
return (ProcessHandle__
p_,ProcessHandle__
p_)
  case ProcessHandle__
p_ of
    ClosedHandle ExitCode
e -> forall (m :: * -> *) a. Monad m => a -> m a
return ExitCode
e
    OpenHandle Pid
h  -> do
        -- don't hold the MVar while we call c_waitForProcess...
        ExitCode
e <- Pid -> IO ExitCode
waitForProcess' Pid
h
        (ExitCode
e', Bool
was_open) <- forall a.
ProcessHandle
-> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
modifyProcessHandle ProcessHandle
ph forall a b. (a -> b) -> a -> b
$ \ProcessHandle__
p_' ->
          case ProcessHandle__
p_' of
            ClosedHandle ExitCode
e' -> forall (m :: * -> *) a. Monad m => a -> m a
return (ProcessHandle__
p_', (ExitCode
e', Bool
False))
            OpenExtHandle{} -> forall (m :: * -> *) a. MonadFail m => String -> m a
fail String
"waitForProcess(OpenExtHandle): this cannot happen"
            OpenHandle Pid
ph'  -> do
              Pid -> IO ()
closePHANDLE Pid
ph'
              forall (m :: * -> *) a. Monad m => a -> m a
return (ExitCode -> ProcessHandle__
ClosedHandle ExitCode
e, (ExitCode
e, Bool
True))
        -- endDelegateControlC after closing the handle, since it
        -- may throw UserInterrupt
        forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool
was_open Bool -> Bool -> Bool
&& Bool
delegating_ctlc) forall a b. (a -> b) -> a -> b
$
          ExitCode -> IO ()
endDelegateControlC ExitCode
e
        forall (m :: * -> *) a. Monad m => a -> m a
return ExitCode
e'
#if defined(WINDOWS)
    OpenExtHandle h job -> do
        -- First wait for completion of the job...
        waitForJobCompletion job
        e <- waitForProcess' h
        e' <- modifyProcessHandle ph $ \p_' ->
          case p_' of
            ClosedHandle e' -> return (p_', e')
            OpenHandle{}    -> fail "waitForProcess(OpenHandle): this cannot happen"
            OpenExtHandle ph' job' -> do
              closePHANDLE ph'
              closePHANDLE job'
              return (ClosedHandle e, e)
        -- omit endDelegateControlC since it's a no-op on Windows
        return e'
#else
    OpenExtHandle Pid
_ Pid
_job ->
        forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ Int -> ExitCode
ExitFailure (-Int
1)
#endif
  where
    -- If more than one thread calls `waitpid` at a time, `waitpid` will
    -- return the exit code to one of them and (-1) to the rest of them,
    -- causing an exception to be thrown.
    -- Cf. https://github.com/haskell/process/issues/46, and
    -- https://github.com/haskell/process/pull/58 for further discussion
    lockWaitpid :: IO b -> IO b
lockWaitpid IO b
m = forall a b. MVar a -> (a -> IO b) -> IO b
withMVar (ProcessHandle -> MVar ()
waitpidLock ProcessHandle
ph) forall a b. (a -> b) -> a -> b
$ \() -> IO b
m

    waitForProcess' :: PHANDLE -> IO ExitCode
    waitForProcess' :: Pid -> IO ExitCode
waitForProcess' Pid
h = forall a b. Storable a => (Ptr a -> IO b) -> IO b
alloca forall a b. (a -> b) -> a -> b
$ \Ptr CInt
pret -> do
      forall a. (Eq a, Num a) => String -> IO a -> IO ()
throwErrnoIfMinus1Retry_ String
"waitForProcess" (IO ()
allowInterrupt forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> Pid -> Ptr CInt -> IO CInt
c_waitForProcess Pid
h Ptr CInt
pret)
      CInt -> ExitCode
mkExitCode forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. Storable a => Ptr a -> IO a
peek Ptr CInt
pret

    mkExitCode :: CInt -> ExitCode
    mkExitCode :: CInt -> ExitCode
mkExitCode CInt
code
      | CInt
code forall a. Eq a => a -> a -> Bool
== CInt
0 = ExitCode
ExitSuccess
      | Bool
otherwise = Int -> ExitCode
ExitFailure (forall a b. (Integral a, Num b) => a -> b
fromIntegral CInt
code)


-- ----------------------------------------------------------------------------
-- getProcessExitCode

{- |
This is a non-blocking version of 'waitForProcess'.  If the process is
still running, 'Nothing' is returned.  If the process has exited, then
@'Just' e@ is returned where @e@ is the exit code of the process.

On Unix systems, see 'waitForProcess' for the meaning of exit codes
when the process died as the result of a signal. May throw
'UserInterrupt' when using 'delegate_ctlc'.
-}

getProcessExitCode :: ProcessHandle -> IO (Maybe ExitCode)
getProcessExitCode :: ProcessHandle -> IO (Maybe ExitCode)
getProcessExitCode ph :: ProcessHandle
ph@(ProcessHandle MVar ProcessHandle__
_ Bool
delegating_ctlc MVar ()
_) = IO (Maybe ExitCode) -> IO (Maybe ExitCode)
tryLockWaitpid forall a b. (a -> b) -> a -> b
$ do
  (Maybe ExitCode
m_e, Bool
was_open) <- forall a.
ProcessHandle
-> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a
modifyProcessHandle ProcessHandle
ph forall a b. (a -> b) -> a -> b
$ \ProcessHandle__
p_ ->
    case ProcessHandle__
p_ of
      ClosedHandle ExitCode
e -> forall (m :: * -> *) a. Monad m => a -> m a
return (ProcessHandle__
p_, (forall a. a -> Maybe a
Just ExitCode
e, Bool
False))
      ProcessHandle__
open -> do
        forall a b. Storable a => (Ptr a -> IO b) -> IO b
alloca forall a b. (a -> b) -> a -> b
$ \Ptr CInt
pExitCode -> do
          case ProcessHandle__ -> Maybe Pid
getHandle ProcessHandle__
open of
            Maybe Pid
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return (ProcessHandle__
p_, (forall a. Maybe a
Nothing, Bool
False))
            Just Pid
h  -> do
                CInt
res <- forall a. (Eq a, Num a) => String -> IO a -> IO a
throwErrnoIfMinus1Retry String
"getProcessExitCode" forall a b. (a -> b) -> a -> b
$
                                        Pid -> Ptr CInt -> IO CInt
c_getProcessExitCode Pid
h Ptr CInt
pExitCode
                CInt
code <- forall a. Storable a => Ptr a -> IO a
peek Ptr CInt
pExitCode
                if CInt
res forall a. Eq a => a -> a -> Bool
== CInt
0
                   then forall (m :: * -> *) a. Monad m => a -> m a
return (ProcessHandle__
p_, (forall a. Maybe a
Nothing, Bool
False))
                   else do
                        Pid -> IO ()
closePHANDLE Pid
h
                        let e :: ExitCode
e  | CInt
code forall a. Eq a => a -> a -> Bool
== CInt
0 = ExitCode
ExitSuccess
                               | Bool
otherwise = Int -> ExitCode
ExitFailure (forall a b. (Integral a, Num b) => a -> b
fromIntegral CInt
code)
                        forall (m :: * -> *) a. Monad m => a -> m a
return (ExitCode -> ProcessHandle__
ClosedHandle ExitCode
e, (forall a. a -> Maybe a
Just ExitCode
e, Bool
True))
  -- endDelegateControlC after closing the handle, since it
  -- may throw UserInterrupt
  case Maybe ExitCode
m_e of
    Just ExitCode
e | Bool
was_open Bool -> Bool -> Bool
&& Bool
delegating_ctlc -> ExitCode -> IO ()
endDelegateControlC ExitCode
e
    Maybe ExitCode
_                                    -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
  forall (m :: * -> *) a. Monad m => a -> m a
return Maybe ExitCode
m_e
    where getHandle :: ProcessHandle__ -> Maybe PHANDLE
          getHandle :: ProcessHandle__ -> Maybe Pid
getHandle (OpenHandle        Pid
h) = forall a. a -> Maybe a
Just Pid
h
          getHandle (ClosedHandle      ExitCode
_) = forall a. Maybe a
Nothing
          getHandle (OpenExtHandle   Pid
h Pid
_) = forall a. a -> Maybe a
Just Pid
h

          -- If somebody is currently holding the waitpid lock, we don't want to
          -- accidentally remove the pid from the process table.
          -- Try acquiring the waitpid lock. If it is held, we are done
          -- since that means the process is still running and we can return
          -- `Nothing`. If it is not held, acquire it so we can run the
          -- (non-blocking) call to `waitpid` without worrying about any
          -- other threads calling it at the same time.
          tryLockWaitpid :: IO (Maybe ExitCode) -> IO (Maybe ExitCode)
          tryLockWaitpid :: IO (Maybe ExitCode) -> IO (Maybe ExitCode)
tryLockWaitpid IO (Maybe ExitCode)
action = forall a b c. IO a -> (a -> IO b) -> (a -> IO c) -> IO c
bracket IO (Maybe ())
acquire Maybe () -> IO ()
release Maybe () -> IO (Maybe ExitCode)
between
            where
              acquire :: IO (Maybe ())
acquire   = forall a. MVar a -> IO (Maybe a)
tryTakeMVar (ProcessHandle -> MVar ()
waitpidLock ProcessHandle
ph)
              release :: Maybe () -> IO ()
release Maybe ()
m = case Maybe ()
m of
                Maybe ()
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
                Just () -> forall a. MVar a -> a -> IO ()
putMVar (ProcessHandle -> MVar ()
waitpidLock ProcessHandle
ph) ()
              between :: Maybe () -> IO (Maybe ExitCode)
between Maybe ()
m = case Maybe ()
m of
                Maybe ()
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return forall a. Maybe a
Nothing
                Just () -> IO (Maybe ExitCode)
action

-- ----------------------------------------------------------------------------
-- terminateProcess

-- | Attempts to terminate the specified process.  This function should
-- not be used under normal circumstances - no guarantees are given regarding
-- how cleanly the process is terminated.  To check whether the process
-- has indeed terminated, use 'getProcessExitCode'.
--
-- On Unix systems, 'terminateProcess' sends the process the SIGTERM signal.
-- On Windows systems, if `use_process_jobs` is `True` then the Win32 @TerminateJobObject@
-- function is called to kill all processes associated with the job and passing the
-- exit code of 1 to each of them. Otherwise if `use_process_jobs` is `False` then the
-- Win32 @TerminateProcess@ function is called, passing an exit code of 1.
--
-- Note: on Windows, if the process was a shell command created by
-- 'createProcess' with 'shell', or created by 'runCommand' or
-- 'runInteractiveCommand', then 'terminateProcess' will only
-- terminate the shell, not the command itself.  On Unix systems, both
-- processes are in a process group and will be terminated together.

terminateProcess :: ProcessHandle -> IO ()
terminateProcess :: ProcessHandle -> IO ()
terminateProcess ProcessHandle
ph = do
  forall a. ProcessHandle -> (ProcessHandle__ -> IO a) -> IO a
withProcessHandle ProcessHandle
ph forall a b. (a -> b) -> a -> b
$ \ProcessHandle__
p_ ->
    case ProcessHandle__
p_ of
      ClosedHandle  ExitCode
_ -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
#if defined(WINDOWS)
      OpenExtHandle{} -> terminateJobUnsafe p_ 1 >> return ()
#else
      OpenExtHandle{} -> forall a. HasCallStack => String -> a
error String
"terminateProcess with OpenExtHandle should not happen on POSIX."
#endif
      OpenHandle    Pid
h -> do
        forall a. (Eq a, Num a) => String -> IO a -> IO ()
throwErrnoIfMinus1Retry_ String
"terminateProcess" forall a b. (a -> b) -> a -> b
$ Pid -> IO CInt
c_terminateProcess Pid
h
        forall (m :: * -> *) a. Monad m => a -> m a
return ()
        -- does not close the handle, we might want to try terminating it
        -- again, or get its exit code.


-- ----------------------------------------------------------------------------
-- Interface to C bits

foreign import ccall unsafe "terminateProcess"
  c_terminateProcess
        :: PHANDLE
        -> IO CInt

foreign import ccall unsafe "getProcessExitCode"
  c_getProcessExitCode
        :: PHANDLE
        -> Ptr CInt
        -> IO CInt

foreign import ccall interruptible "waitForProcess" -- NB. safe - can block
  c_waitForProcess
        :: PHANDLE
        -> Ptr CInt
        -> IO CInt


-- ----------------------------------------------------------------------------
-- Old deprecated variants
-- ----------------------------------------------------------------------------

-- TODO: We're not going to mark these functions as DEPRECATED immediately in
-- process-1.2.0.0. That's because some of their replacements have not been
-- around for all that long. But they should eventually be marked with a
-- suitable DEPRECATED pragma after a release or two.


-- ----------------------------------------------------------------------------
-- runCommand

--TODO: in a later release {-# DEPRECATED runCommand "Use 'spawnCommand' instead" #-}

{- | Runs a command using the shell.
 -}
runCommand
  :: String
  -> IO ProcessHandle

runCommand :: String -> IO ProcessHandle
runCommand String
string = do
  (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
ph) <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"runCommand" (String -> CreateProcess
shell String
string)
  forall (m :: * -> *) a. Monad m => a -> m a
return ProcessHandle
ph


-- ----------------------------------------------------------------------------
-- runProcess

--TODO: in a later release {-# DEPRECATED runProcess "Use 'spawnProcess' or 'createProcess' instead" #-}

{- | Runs a raw command, optionally specifying 'Handle's from which to
     take the @stdin@, @stdout@ and @stderr@ channels for the new
     process (otherwise these handles are inherited from the current
     process).

     Any 'Handle's passed to 'runProcess' are placed immediately in the
     closed state.

     Note: consider using the more general 'createProcess' instead of
     'runProcess'.
-}
runProcess
  :: FilePath                   -- ^ Filename of the executable (see 'RawCommand' for details)
  -> [String]                   -- ^ Arguments to pass to the executable
  -> Maybe FilePath             -- ^ Optional path to the working directory
  -> Maybe [(String,String)]    -- ^ Optional environment (otherwise inherit)
  -> Maybe Handle               -- ^ Handle to use for @stdin@ (Nothing => use existing @stdin@)
  -> Maybe Handle               -- ^ Handle to use for @stdout@ (Nothing => use existing @stdout@)
  -> Maybe Handle               -- ^ Handle to use for @stderr@ (Nothing => use existing @stderr@)
  -> IO ProcessHandle

runProcess :: String
-> [String]
-> Maybe String
-> Maybe [(String, String)]
-> Maybe Handle
-> Maybe Handle
-> Maybe Handle
-> IO ProcessHandle
runProcess String
cmd [String]
args Maybe String
mb_cwd Maybe [(String, String)]
mb_env Maybe Handle
mb_stdin Maybe Handle
mb_stdout Maybe Handle
mb_stderr = do
  (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
ph) <-
      String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"runProcess"
         (String -> [String] -> CreateProcess
proc String
cmd [String]
args){ cwd :: Maybe String
cwd = Maybe String
mb_cwd,
                          env :: Maybe [(String, String)]
env = Maybe [(String, String)]
mb_env,
                          std_in :: StdStream
std_in  = Maybe Handle -> StdStream
mbToStd Maybe Handle
mb_stdin,
                          std_out :: StdStream
std_out = Maybe Handle -> StdStream
mbToStd Maybe Handle
mb_stdout,
                          std_err :: StdStream
std_err = Maybe Handle -> StdStream
mbToStd Maybe Handle
mb_stderr }
  Maybe Handle -> IO ()
maybeClose Maybe Handle
mb_stdin
  Maybe Handle -> IO ()
maybeClose Maybe Handle
mb_stdout
  Maybe Handle -> IO ()
maybeClose Maybe Handle
mb_stderr
  forall (m :: * -> *) a. Monad m => a -> m a
return ProcessHandle
ph
 where
  maybeClose :: Maybe Handle -> IO ()
  maybeClose :: Maybe Handle -> IO ()
maybeClose (Just  Handle
hdl)
    | Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stdin Bool -> Bool -> Bool
&& Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stdout Bool -> Bool -> Bool
&& Handle
hdl forall a. Eq a => a -> a -> Bool
/= Handle
stderr = Handle -> IO ()
hClose Handle
hdl
  maybeClose Maybe Handle
_ = forall (m :: * -> *) a. Monad m => a -> m a
return ()

  mbToStd :: Maybe Handle -> StdStream
  mbToStd :: Maybe Handle -> StdStream
mbToStd Maybe Handle
Nothing    = StdStream
Inherit
  mbToStd (Just Handle
hdl) = Handle -> StdStream
UseHandle Handle
hdl


-- ----------------------------------------------------------------------------
-- runInteractiveCommand

--TODO: in a later release {-# DEPRECATED runInteractiveCommand "Use 'createProcess' instead" #-}

{- | Runs a command using the shell, and returns 'Handle's that may
     be used to communicate with the process via its @stdin@, @stdout@,
     and @stderr@ respectively.
-}
runInteractiveCommand
  :: String
  -> IO (Handle,Handle,Handle,ProcessHandle)

runInteractiveCommand :: String -> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveCommand String
string =
  String
-> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveProcess1 String
"runInteractiveCommand" (String -> CreateProcess
shell String
string)


-- ----------------------------------------------------------------------------
-- runInteractiveProcess

--TODO: in a later release {-# DEPRECATED runInteractiveCommand "Use 'createProcess' instead" #-}

{- | Runs a raw command, and returns 'Handle's that may be used to communicate
     with the process via its @stdin@, @stdout@ and @stderr@ respectively.

    For example, to start a process and feed a string to its stdin:

>   (inp,out,err,pid) <- runInteractiveProcess "..."
>   forkIO (hPutStr inp str)
-}
runInteractiveProcess
  :: FilePath                   -- ^ Filename of the executable (see 'RawCommand' for details)
  -> [String]                   -- ^ Arguments to pass to the executable
  -> Maybe FilePath             -- ^ Optional path to the working directory
  -> Maybe [(String,String)]    -- ^ Optional environment (otherwise inherit)
  -> IO (Handle,Handle,Handle,ProcessHandle)

runInteractiveProcess :: String
-> [String]
-> Maybe String
-> Maybe [(String, String)]
-> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveProcess String
cmd [String]
args Maybe String
mb_cwd Maybe [(String, String)]
mb_env = do
  String
-> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveProcess1 String
"runInteractiveProcess"
        (String -> [String] -> CreateProcess
proc String
cmd [String]
args){ cwd :: Maybe String
cwd = Maybe String
mb_cwd, env :: Maybe [(String, String)]
env = Maybe [(String, String)]
mb_env }

runInteractiveProcess1
  :: String
  -> CreateProcess
  -> IO (Handle,Handle,Handle,ProcessHandle)
runInteractiveProcess1 :: String
-> CreateProcess -> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveProcess1 String
fun CreateProcess
cmd = do
  (Maybe Handle
mb_in, Maybe Handle
mb_out, Maybe Handle
mb_err, ProcessHandle
p) <-
      String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
fun
           CreateProcess
cmd{ std_in :: StdStream
std_in  = StdStream
CreatePipe,
                std_out :: StdStream
std_out = StdStream
CreatePipe,
                std_err :: StdStream
std_err = StdStream
CreatePipe }
  forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. HasCallStack => Maybe a -> a
fromJust Maybe Handle
mb_in, forall a. HasCallStack => Maybe a -> a
fromJust Maybe Handle
mb_out, forall a. HasCallStack => Maybe a -> a
fromJust Maybe Handle
mb_err, ProcessHandle
p)


-- ---------------------------------------------------------------------------
-- system & rawSystem

--TODO: in a later release {-# DEPRECATED system "Use 'callCommand' (or 'spawnCommand' and 'waitForProcess') instead" #-}

{-|
Computation @system cmd@ returns the exit code produced when the
operating system runs the shell command @cmd@.

This computation may fail with one of the following
'System.IO.Error.IOErrorType' exceptions:

[@PermissionDenied@]
The process has insufficient privileges to perform the operation.

[@ResourceExhausted@]
Insufficient resources are available to perform the operation.

[@UnsupportedOperation@]
The implementation does not support system calls.

On Windows, 'system' passes the command to the Windows command
interpreter (@CMD.EXE@ or @COMMAND.COM@), hence Unixy shell tricks
will not work.

On Unix systems, see 'waitForProcess' for the meaning of exit codes
when the process died as the result of a signal.
-}
system :: String -> IO ExitCode
system :: String -> IO ExitCode
system String
"" = forall a. IOException -> IO a
ioException (IOException -> String -> IOException
ioeSetErrorString (IOErrorType
-> String -> Maybe Handle -> Maybe String -> IOException
mkIOError IOErrorType
InvalidArgument String
"system" forall a. Maybe a
Nothing forall a. Maybe a
Nothing) String
"null command")
system String
str = do
  (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
p) <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"system" (String -> CreateProcess
shell String
str) { delegate_ctlc :: Bool
delegate_ctlc = Bool
True }
  ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
p


--TODO: in a later release {-# DEPRECATED rawSystem "Use 'callProcess' (or 'spawnProcess' and 'waitForProcess') instead" #-}

{-|
The computation @'rawSystem' /cmd/ /args/@ runs the operating system command
@/cmd/@ in such a way that it receives as arguments the @/args/@ strings
exactly as given, with no funny escaping or shell meta-syntax expansion.
It will therefore behave more portably between operating systems than 'system'.

The return codes and possible failures are the same as for 'system'.
-}
rawSystem :: String -> [String] -> IO ExitCode
rawSystem :: String -> [String] -> IO ExitCode
rawSystem String
cmd [String]
args = do
  (Maybe Handle
_,Maybe Handle
_,Maybe Handle
_,ProcessHandle
p) <- String
-> CreateProcess
-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)
createProcess_ String
"rawSystem" (String -> [String] -> CreateProcess
proc String
cmd [String]
args) { delegate_ctlc :: Bool
delegate_ctlc = Bool
True }
  ProcessHandle -> IO ExitCode
waitForProcess ProcessHandle
p