System.Process.Internals

Note: This module exports internal implementation details that may change anytime. If you want a more stable API, use System.Process instead.

Documentation

data ProcessHandle

A handle to a process, which can be used to wait for termination of the process using waitForProcess.

None of the process-creation functions in this library wait for termination: they all return a ProcessHandle which may be used to wait for the process later.

On Windows a second wait method can be used to block for event completion. This requires two handles. A process job handle and a events handle to monitor.

Constructors

ProcessHandle

Fields

• phandle :: !(MVar ProcessHandle__)
• mb_delegate_ctlc :: !Bool
• waitpidLock :: !(MVar ())

data ProcessHandle__

Constructors

OpenHandle

Fields

• phdlProcessHandle :: PHANDLE

  the process

OpenExtHandle

Fields

• phdlProcessHandle :: PHANDLE

  the process

• phdlJobHandle :: PHANDLE

  the job containing the process and its subprocesses

ClosedHandle ExitCode

type PHANDLE = CPid

closePHANDLE :: PHANDLE -> IO ()

mkProcessHandle :: PHANDLE -> Bool -> IO ProcessHandle

data CGid

Instances

Bounded CGid

Defined in System.Posix.Types

Methods

minBound :: CGid

maxBound :: CGid

Enum CGid

Defined in System.Posix.Types

Methods

succ :: CGid -> CGid

pred :: CGid -> CGid

toEnum :: Int -> CGid

fromEnum :: CGid -> Int

enumFrom :: CGid -> [CGid]

enumFromThen :: CGid -> CGid -> [CGid]

enumFromTo :: CGid -> CGid -> [CGid]

enumFromThenTo :: CGid -> CGid -> CGid -> [CGid]

Eq CGid

Defined in System.Posix.Types

Methods

(==) :: CGid -> CGid -> Bool

(/=) :: CGid -> CGid -> Bool

Integral CGid

Defined in System.Posix.Types

Methods

quot :: CGid -> CGid -> CGid

rem :: CGid -> CGid -> CGid

div :: CGid -> CGid -> CGid

mod :: CGid -> CGid -> CGid

quotRem :: CGid -> CGid -> (CGid, CGid)

divMod :: CGid -> CGid -> (CGid, CGid)

toInteger :: CGid -> Integer

Num CGid

Defined in System.Posix.Types

Methods

(+) :: CGid -> CGid -> CGid

(-) :: CGid -> CGid -> CGid

(*) :: CGid -> CGid -> CGid

negate :: CGid -> CGid

abs :: CGid -> CGid

signum :: CGid -> CGid

fromInteger :: Integer -> CGid

Ord CGid

Defined in System.Posix.Types

Methods

compare :: CGid -> CGid -> Ordering

(<) :: CGid -> CGid -> Bool

(<=) :: CGid -> CGid -> Bool

(>) :: CGid -> CGid -> Bool

(>=) :: CGid -> CGid -> Bool

max :: CGid -> CGid -> CGid

min :: CGid -> CGid -> CGid

Read CGid

Defined in System.Posix.Types

Methods

readsPrec :: Int -> ReadS CGid

readList :: ReadS [CGid]

readPrec :: ReadPrec CGid

readListPrec :: ReadPrec [CGid]

Real CGid

Defined in System.Posix.Types

Methods

toRational :: CGid -> Rational

Show CGid

Defined in System.Posix.Types

Methods

showsPrec :: Int -> CGid -> ShowS

show :: CGid -> String

showList :: [CGid] -> ShowS

Storable CGid

Defined in System.Posix.Types

Methods

sizeOf :: CGid -> Int

alignment :: CGid -> Int

peekElemOff :: Ptr CGid -> Int -> IO CGid

pokeElemOff :: Ptr CGid -> Int -> CGid -> IO ()

peekByteOff :: Ptr b -> Int -> IO CGid

pokeByteOff :: Ptr b -> Int -> CGid -> IO ()

peek :: Ptr CGid -> IO CGid

poke :: Ptr CGid -> CGid -> IO ()

Bits CGid

Defined in System.Posix.Types

Methods

(.&.) :: CGid -> CGid -> CGid

(.|.) :: CGid -> CGid -> CGid

xor :: CGid -> CGid -> CGid

complement :: CGid -> CGid

shift :: CGid -> Int -> CGid

rotate :: CGid -> Int -> CGid

zeroBits :: CGid

bit :: Int -> CGid

setBit :: CGid -> Int -> CGid

clearBit :: CGid -> Int -> CGid

complementBit :: CGid -> Int -> CGid

testBit :: CGid -> Int -> Bool

bitSizeMaybe :: CGid -> Maybe Int

bitSize :: CGid -> Int

isSigned :: CGid -> Bool

shiftL :: CGid -> Int -> CGid

unsafeShiftL :: CGid -> Int -> CGid

shiftR :: CGid -> Int -> CGid

unsafeShiftR :: CGid -> Int -> CGid

rotateL :: CGid -> Int -> CGid

rotateR :: CGid -> Int -> CGid

popCount :: CGid -> Int

FiniteBits CGid

Defined in System.Posix.Types

Methods

finiteBitSize :: CGid -> Int

countLeadingZeros :: CGid -> Int

countTrailingZeros :: CGid -> Int

type GroupID = CGid

type UserID = CUid

modifyProcessHandle :: ProcessHandle -> (ProcessHandle__ -> IO (ProcessHandle__, a)) -> IO a

withProcessHandle :: ProcessHandle -> (ProcessHandle__ -> IO a) -> IO a

data CreateProcess

Constructors

CreateProcess

Fields

• cmdspec :: CmdSpec

  Executable & arguments, or shell command. If cwd is Nothing, relative paths are resolved with respect to the current working directory. If cwd is provided, it is implementation-dependent whether relative paths are resolved with respect to cwd or the current working directory, so absolute paths should be used to ensure portability.

• cwd :: Maybe FilePath

  Optional path to the working directory for the new process

• env :: Maybe [(String, String)]

  Optional environment (otherwise inherit from the current process)

• std_in :: StdStream

  How to determine stdin

• std_out :: StdStream

  How to determine stdout

• std_err :: StdStream

  How to determine stderr

• close_fds :: Bool

  Close all file descriptors except stdin, stdout and stderr in the new process (on Windows, only works if std_in, std_out, and std_err are all Inherit). This implementation will call close an every fd from 3 to the maximum of open files, which can be slow for high maximum of open files.

• create_group :: Bool

  Create a new process group

• delegate_ctlc :: Bool

  Delegate control-C handling. Use this for interactive console processes to let them handle control-C themselves (see below for details).

  On Windows this has no effect.

  Since: 1.2.0.0

• detach_console :: Bool

  Use the windows DETACHED_PROCESS flag when creating the process; does nothing on other platforms.

  Since: 1.3.0.0

• create_new_console :: Bool

  Use the windows CREATE_NEW_CONSOLE flag when creating the process; does nothing on other platforms.

  Default: False

  Since: 1.3.0.0

• new_session :: Bool

  Use posix setsid to start the new process in a new session; does nothing on other platforms.

  Since: 1.3.0.0

• child_group :: Maybe GroupID

  Use posix setgid to set child process's group id; does nothing on other platforms.

  Default: Nothing

  Since: 1.4.0.0

• child_user :: Maybe UserID

  Use posix setuid to set child process's user id; does nothing on other platforms.

  Default: Nothing

  Since: 1.4.0.0

• use_process_jobs :: Bool

  On Windows systems this flag indicates that we should wait for the entire process tree to finish before unblocking. On POSIX systems this flag is ignored. See $exec-on-windows for details.

  Default: False

  Since: 1.5.0.0

Instances

Eq CreateProcess

Defined in System.Process.Common

Methods

(==) :: CreateProcess -> CreateProcess -> Bool

(/=) :: CreateProcess -> CreateProcess -> Bool

Show CreateProcess

Defined in System.Process.Common

Methods

showsPrec :: Int -> CreateProcess -> ShowS

show :: CreateProcess -> String

showList :: [CreateProcess] -> ShowS

data CmdSpec

Constructors

ShellCommand String

A command line to execute using the shell

RawCommand FilePath [String]

The name of an executable with a list of arguments

The FilePath argument names the executable, and is interpreted according to the platform's standard policy for searching for executables. Specifically:

• on Unix systems the execvp(3) semantics is used, where if the executable filename does not contain a slash (/) then the PATH environment variable is searched for the executable.
• on Windows systems the Win32 CreateProcess semantics is used. Briefly: if the filename does not contain a path, then the directory containing the parent executable is searched, followed by the current directory, then some standard locations, and finally the current PATH. An .exe extension is added if the filename does not already have an extension. For full details see the documentation for the Windows SearchPath API.

Instances

Eq CmdSpec

Defined in System.Process.Common

Methods

(==) :: CmdSpec -> CmdSpec -> Bool

(/=) :: CmdSpec -> CmdSpec -> Bool

Show CmdSpec

Defined in System.Process.Common

Methods

showsPrec :: Int -> CmdSpec -> ShowS

show :: CmdSpec -> String

showList :: [CmdSpec] -> ShowS

IsString CmdSpec

construct a ShellCommand from a string literal

Since: 1.2.1.0

Defined in System.Process.Common

Methods

fromString :: String -> CmdSpec

data StdStream

Constructors

Inherit

Inherit Handle from parent

UseHandle Handle

Use the supplied Handle

CreatePipe

Create a new pipe. The returned Handle will use the default encoding and newline translation mode (just like Handles created by openFile).

NoStream

Close the stream's file descriptor without passing a Handle. On POSIX systems this may lead to strange behavior in the child process because attempting to read or write after the file has been closed throws an error. This should only be used with child processes that don't use the file descriptor at all. If you wish to ignore the child process's output you should either create a pipe and drain it manually or pass a Handle that writes to /dev/null.

Instances

Eq StdStream

Defined in System.Process.Common

Methods

(==) :: StdStream -> StdStream -> Bool

(/=) :: StdStream -> StdStream -> Bool

Show StdStream

Defined in System.Process.Common

Methods

showsPrec :: Int -> StdStream -> ShowS

show :: StdStream -> String

showList :: [StdStream] -> ShowS

data ProcRetHandles

contains the handles returned by a call to createProcess_Internal

Constructors

ProcRetHandles

Fields

• hStdInput :: Maybe Handle
• hStdOutput :: Maybe Handle
• hStdError :: Maybe Handle
• procHandle :: ProcessHandle

createProcess_

Arguments

:: String

Function name (for error messages).

This can be any String, but will typically be the name of the caller. E.g., spawnProcess passes "spawnProcess" here when calling createProcess_.

-> CreateProcess

-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

This function is almost identical to createProcess. The only differences are:

• Handles provided via UseHandle are not closed automatically.
• This function takes an extra String argument to be used in creating error messages.

This function has been available from the System.Process.Internals module for some time, and is part of the System.Process module since version 1.2.1.0.

Since: 1.2.1.0

runGenProcess_

Arguments

:: String

function name (for error messages)

-> CreateProcess

-> Maybe CLong

handler for SIGINT

-> Maybe CLong

handler for SIGQUIT

-> IO (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

Deprecated: Please do not use this anymore, use the ordinary createProcess. If you need the SIGINT handling, use delegate_ctlc = True (runGenProcess_ is now just an imperfectly emulated stub that probably duplicates or overrides your own signal handling).

fdToHandle :: FD -> IO Handle

Turn an existing file descriptor into a Handle. This is used by various external libraries to make Handles.

Makes a binary Handle. This is for historical reasons; it should probably be a text Handle with the default encoding and newline translation instead.

startDelegateControlC :: IO ()

endDelegateControlC :: ExitCode -> IO ()

stopDelegateControlC :: IO ()

unwrapHandles :: ProcRetHandles -> (Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle)

pPrPr_disableITimers :: IO ()

c_execvpe :: CString -> Ptr CString -> Ptr CString -> IO CInt

ignoreSignal :: CLong

defaultSignal :: CLong

runInteractiveProcess_lock :: MVar ()

runInteractiveProcess blocks signals around the fork(). Since blocking/unblocking of signals is a global state operation, we need to ensure mutual exclusion of calls to runInteractiveProcess. This lock is exported so that other libraries which also need to fork() (and also need to make the same global state changes) can protect their changes with the same lock. See https://github.com/haskell/process/pull/154.

Since: 1.6.6.0

withFilePathException :: FilePath -> IO a -> IO a

withCEnvironment :: [(String, String)] -> (Ptr CString -> IO a) -> IO a

translate :: String -> String

createPipe :: IO (Handle, Handle)

Create a pipe for interprocess communication and return a (readEnd, writeEnd) Handle pair.

• WinIO Support

When this function is used with WinIO enabled it's the caller's responsibility to register the handles with the I/O manager. If this is not done the operation will deadlock. Association can be done as follows:

    #if defined(IO_MANAGER_WINIO)
    import GHC.IO.SubSystem ((!))
    import GHC.IO.Handle.Windows (handleToHANDLE)
    import GHC.Event.Windows (associateHandle')
    #endif

    ...

    #if defined (IO_MANAGER_WINIO)
    return () ! (do
      associateHandle' =handleToHANDLE <handle)
    #endif

Only associate handles that you are in charge of read/writing to. Do not associate handles passed to another process. It's the process's reponsibility to register the handle if it supports async access.

Since: 1.2.1.0

createPipeFd :: IO (FD, FD)

Create a pipe for interprocess communication and return a (readEnd, writeEnd) FD pair.

Since: 1.4.2.0

interruptProcessGroupOf

Arguments

:: ProcessHandle

A process in the process group

-> IO ()

Sends an interrupt signal to the process group of the given process.

On Unix systems, it sends the group the SIGINT signal.

On Windows systems, it generates a CTRL_BREAK_EVENT and will only work for processes created using createProcess and setting the create_group flag