import Foreign.C
import System.Exit
import GHC.IOBase
-#include "config.h"
+#include "ghcconfig.h"
#endif
#ifdef __HUGS__
foreign import ccall unsafe "systemCmd" primSystem :: CString -> IO Int
+-- ---------------------------------------------------------------------------
+-- rawSystem
-------------------------------------------------------------------------
---
--- 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@.
--}
-
-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. Again, to
- break it into argument items, any spaces must be quoted using
- double quote thus
- cmd "this is arg 1" "this is arg 2"
-
-What if an argument itself contains double-quotes? (File names can't
-can't, on Windows.) Then the quote must be escaped with a backslash.
-If we call Create Process with this lpArgument:
- cmd "Foo=\"baz\"" arg2
-then cmd will see argv[1] as
- Foo="baz"
-However, experiments show that backslashes themselves must *not* be escaped.
-That is, to get a backslash in an argument, just put backslash, even inside
-quotes. For eaxmple, this works fine to show the contents of the file
-foo\baz
- cat "foo\baz"
-If you escape the backslash, thus
- cat "foo\\baz"
-then @cat@ will see argument foo\\baz, and on WinME/98/95 you'll get
-"can't find file foo\\baz". (As it happens, WinNT/XP commands don't
-mind double backslashes, but it's still a bug, given rawSystem's claim
-to pass exactly args to the command.)
-
-BOTTOM LINE:
- 1 We wrap the command, and each argument, in quotes
- 2 Inside the quotes, we escape any double-quote characters
- (but nothing else)
- 3 Then concatenate all these quoted things together, separated with
- spaces
-
-Steps 1,2 are done by the function 'translate' below.
-
-The exact rules used by the C runtime to unscramble quoted argumets
-are quite complex. For example, how do you get the string \" into an
-argument? You can find the rules in MSDN, here:
- http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccelng/htm/progs_12.asp
-
-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 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.
-translate str = '"' : foldr escape "\"" str
- where escape '"' str = '\\' : '"' : str
- escape c str = c : str
-
-foreign import ccall unsafe "rawSystem"
- c_rawSystem :: CString -> IO Int
-
-#endif
+-- rawSystem is in a separate file, so we can #include it various places.
+#include "RawSystem.hs-inc"
#endif /* __GLASGOW_HASKELL__ */
projects / ghc-base.git / blobdiff