From fc345f2121d1aadd8a07125afb940949d5d0af2b Mon Sep 17 00:00:00 2001 From: simonmar Date: Thu, 6 May 2004 08:44:52 +0000 Subject: [PATCH] [project @ 2004-05-06 08:44:52 by simonmar] Move the definition of rawSystem into a separate file which we #include in the places it is needed. This is slightly better than copying the code, since we now need it in three places (ghc/utils/runghc is the 3rd). --- System/Cmd.hs | 136 ++--------------------------------------------- System/RawSystem.hs-inc | 132 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 137 insertions(+), 131 deletions(-) create mode 100644 System/RawSystem.hs-inc diff --git a/System/Cmd.hs b/System/Cmd.hs index 051380d..cb8d2d9 100644 --- a/System/Cmd.hs +++ b/System/Cmd.hs @@ -71,136 +71,10 @@ system cmd = n -> return (ExitFailure n) foreign import ccall unsafe "systemCmd" primSystem :: CString -> IO Int +#endif /* __GLASGOW_HASKELL__ */ +-- --------------------------------------------------------------------------- +-- 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. 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 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 /* __GLASGOW_HASKELL__ */ +-- rawSystem is in a separate file, so we can #include it various places. +#include "RawSystem.hs-inc" diff --git a/System/RawSystem.hs-inc b/System/RawSystem.hs-inc new file mode 100644 index 0000000..3bac658 --- /dev/null +++ b/System/RawSystem.hs-inc @@ -0,0 +1,132 @@ +------------------------------------------------------------------------ +-- +-- rawSystem +-- +-- This is a separate file #included into Haskell source, because +-- we use it in a few places in the GHC source tree. +-- +------------------------------------------------------------------------ + +{- | +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_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. + -- 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 -- 1.7.10.4