+++ /dev/null
-{-# OPTIONS -cpp #-}
------------------------------------------------------------------------------
--- |
--- Module : Compat.RawSystem
--- Copyright : (c) The University of Glasgow 2001-2004
--- License : BSD-style (see the file libraries/base/LICENSE)
---
--- Maintainer : libraries@haskell.org
--- Stability : provisional
--- Portability : portable
---
--- This is an implementation of rawSystem for use on older versions of GHC
--- which had missing or buggy implementations of this function.
---
------------------------------------------------------------------------------
-
-module Compat.RawSystem (rawSystem) where
-
-#include "../../includes/ghcconfig.h"
-
-#if __GLASGOW_HASKELL__ >= 603
-
-import System.Cmd (rawSystem)
-
-#else /* to end of file */
-
-import System.Exit
-import Foreign
-import Foreign.C
-
-{- |
-The computation @'rawSystem' cmd args@ runs the operating system command
-whose file name is @cmd@, passing it the arguments @args@. It
-bypasses the shell, so that @cmd@ should see precisely the argument
-strings @args@, with no funny escaping or shell meta-syntax expansion.
-(Unix users will recognise this behaviour
-as @execvp@, and indeed that's how it's implemented.)
-It will therefore behave more portably between operating systems than 'system'.
-
-The return codes are the same as for 'system'.
--}
-
-rawSystem :: FilePath -> [String] -> IO ExitCode
-
-{- -------------------------------------------------------------------------
- IMPORTANT IMPLEMENTATION NOTES
- (see also libraries/base/cbits/rawSystem.c)
-
-On Unix, rawSystem is easy to implement: use execvp.
-
-On Windows it's more tricky. We use CreateProcess, passing a single
-command-line string (lpCommandLine) as its argument. (CreateProcess
-is well documented on http://msdn.microsoft/com.)
-
- - It parses the beginning of the string to find the command. If the
- file name has embedded spaces, it must be quoted, using double
- quotes thus
- "foo\this that\cmd" arg1 arg2
-
- - The invoked command can in turn access the entire lpCommandLine string,
- and the C runtime does indeed do so, parsing it to generate the
- traditional argument vector argv[0], argv[1], etc. It does this
- using a complex and arcane set of rules which are described here:
-
- http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccelng/htm/progs_12.asp
-
- (if this URL stops working, you might be able to find it by
- searching for "Parsing C Command-Line Arguments" on MSDN. Also,
- the code in the Microsoft C runtime that does this translation
- is shipped with VC++).
-
-
-Our goal in rawSystem is to take a command filename and list of
-arguments, and construct a string which inverts the translatsions
-described above, such that the program at the other end sees exactly
-the same arguments in its argv[] that we passed to rawSystem.
-
-This inverse translation is implemented by 'translate' below.
-
-Here are some pages that give informations on Windows-related
-limitations and deviations from Unix conventions:
-
- http://support.microsoft.com/default.aspx?scid=kb;en-us;830473
- Command lines and environment variables effectively limited to 8191
- characters on Win XP, 2047 on NT/2000 (probably even less on Win 9x):
-
- http://www.microsoft.com/windowsxp/home/using/productdoc/en/default.asp?url=/WINDOWSXP/home/using/productdoc/en/percent.asp
- Command-line substitution under Windows XP. IIRC these facilities (or at
- least a large subset of them) are available on Win NT and 2000. Some
- might be available on Win 9x.
-
- http://www.microsoft.com/windowsxp/home/using/productdoc/en/default.asp?url=/WINDOWSXP/home/using/productdoc/en/Cmd.asp
- How CMD.EXE processes command lines.
-
-
-Note: CreateProcess does have a separate argument (lpApplicationName)
-with which you can specify the command, but we have to slap the
-command into lpCommandLine anyway, so that argv[0] is what a C program
-expects (namely the application name). So it seems simpler to just
-use lpCommandLine alone, which CreateProcess supports.
-
------------------------------------------------------------------------------ -}
-
-#ifndef mingw32_HOST_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
- -- NOTE: 'cmd' is assumed to contain the application to run _only_,
- -- as it'll be quoted surrounded in quotes here.
- 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@('"':_) = str -- already escaped.
- -- ToDo: this case is wrong. It is only here because we
- -- abuse the system in GHC's SysTools by putting arguments into
- -- the command name; at some point we should fix it up and remove
- -- the case above.
-translate str = '"' : snd (foldr escape (True,"\"") str)
- where escape '"' (b, str) = (True, '\\' : '"' : str)
- escape '\\' (True, str) = (True, '\\' : '\\' : str)
- escape '\\' (False, str) = (False, '\\' : str)
- escape c (b, str) = (False, c : str)
- -- See long comment above for what this function is trying to do.
- --
- -- The Bool passed back along the string is True iff the
- -- rest of the string is a sequence of backslashes followed by
- -- a double quote.
-
-foreign import ccall unsafe "rawSystem"
- c_rawSystem :: CString -> IO Int
-
-#endif
-
-#endif
-
projects / ghc-hetmet.git / blobdiff