module System.Cmd
( system, -- :: String -> IO ExitCode
-#ifdef __GLASGOW_HASKELL__
rawSystem, -- :: FilePath -> [String] -> IO ExitCode
-#endif
) where
import Prelude
+import System.Exit ( ExitCode )
+
#ifdef __GLASGOW_HASKELL__
-import Foreign
-import Foreign.C
-import System.Exit
-import GHC.IOBase
-#include "config.h"
+import System.Process
+import GHC.IOBase ( ioException, IOException(..), IOErrorType(..) )
#endif
#ifdef __HUGS__
#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
+system cmd = do
+ p <- runCommand cmd
+ waitForProcess p
+#endif /* __GLASGOW_HASKELL__ */
+{-|
+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'.
-------------------------------------------------------------------------
---
--- rawSystem
---
-------------------------------------------------------------------------
-
-{- |
-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@.
+The return codes and possible failures 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_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 :: String -> [String] -> IO ExitCode
+#ifdef __GLASGOW_HASKELL__
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)
+ p <- runProcess cmd args Nothing Nothing Nothing Nothing Nothing
+ waitForProcess p
+#else /* ! __GLASGOW_HASKELL__ */
+-- crude fallback implementation: could do much better than this under Unix
+rawSystem cmd args = system (unwords (map translate (cmd:args)))
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.
+#if defined(mingw32_HOST_OS)
+-- copied from System.Process (qv)
translate str = '"' : snd (foldr escape (True,"\"") str)
- where escape '"' (b, str) = (True, '\\' : '"' : str)
- escape '\\' (True, str) = (True, '\\' : '\\' : str)
- escape '\\' (False, str) = (False, '\\' : 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 /* __GLASGOW_HASKELL__ */
+#else /* ! mingw32_HOST_OS */
+translate str = '\'' : foldr escape "'" str
+ where escape '\'' cs = '\'' : '\\' : '\'' : '\'' : cs
+ escape c cs = c : cs
+#endif /* ! mingw32_HOST_OS */
+#endif /* ! __GLASGOW_HASKELL__ */
projects / ghc-base.git / blobdiff