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|
-----------------------------------------------------------------------------
-- |
-- Module : System.Cmd
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : provisional
-- Portability : portable
--
-- Executing an external command.
--
-----------------------------------------------------------------------------
module System.Cmd
( system, -- :: String -> IO ExitCode
#ifdef __GLASGOW_HASKELL__
rawSystem, -- :: FilePath -> [String] -> IO ExitCode
#endif
) where
import Prelude
#ifdef __GLASGOW_HASKELL__
import Foreign
import Foreign.C
import System.Exit
import GHC.IOBase
#include "config.h"
#endif
#ifdef __HUGS__
import Hugs.System
#endif
#ifdef __NHC__
import System (system)
#endif
-- ---------------------------------------------------------------------------
-- system
{-|
Computation @system cmd@ returns the exit code
produced when the operating system processes the command @cmd@.
This computation may fail with
* @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' is implemented using Windows's native system
call, which ignores the @SHELL@ environment variable, and always
passes the command to the Windows command interpreter (@CMD.EXE@ or
@COMMAND.COM@), hence Unixy shell tricks will not work.
-}
#ifdef __GLASGOW_HASKELL__
system :: String -> IO ExitCode
system "" = ioException (IOError Nothing InvalidArgument "system" "null command" Nothing)
system cmd =
withCString cmd $ \s -> do
status <- throwErrnoIfMinus1 "system" (primSystem s)
case status of
0 -> return ExitSuccess
n -> return (ExitFailure n)
foreign import ccall unsafe "systemCmd" primSystem :: CString -> IO Int
{- |
The same as 'system', but bypasses the shell (GHC only).
Will behave more portably between systems,
because there is no interpretation of shell metasyntax.
-}
rawSystem :: FilePath -> [String] -> IO ExitCode
#ifndef mingw32_TARGET_OS
rawSystem cmd args =
withCString cmd $ \pcmd ->
withMany withCString (cmd:args) $ \cstrs ->
withArray0 nullPtr cstrs $ \arr -> do
status <- throwErrnoIfMinus1 "rawSystem" (c_rawSystem pcmd arr)
case status of
0 -> return ExitSuccess
n -> return (ExitFailure n)
foreign import ccall unsafe "rawSystem"
c_rawSystem :: CString -> Ptr CString -> IO Int
#else
-- On Windows, the command line is passed to the operating system as
-- a single string. Command-line parsing is done by the executable
-- itself.
rawSystem cmd args = do
let cmdline = translate cmd ++ concat (map ((' ':) . translate) args)
withCString cmdline $ \pcmdline -> do
status <- throwErrnoIfMinus1 "rawSystem" (c_rawSystem pcmdline)
case status of
0 -> return ExitSuccess
n -> return (ExitFailure n)
translate :: String -> String
translate str = '"' : foldr escape "\"" str
where escape '"' str = '\\' : '"' : str
escape '\\' str = '\\' : '\\' : str
escape c str = c : str
foreign import ccall unsafe "rawSystem"
c_rawSystem :: CString -> IO Int
#endif
#endif /* __GLASGOW_HASKELL__ */
|
