Provide a raw ByteString version of FilePath and environment APIs

The new module System.Posix.ByteString provides exactly the same API
as System.Posix, except that:

  - There is a new type: RawFilePath = ByteString

  - All functions mentioning FilePath in the System.Posix API
    use RawFilePath in the System.Posix.ByteString API

  - RawFilePaths are not subject to Unicode locale encoding and
    decoding, unlike FilePaths.  They are the exact bytes passed to and
    returned from the underlying POSIX API.

  - Similarly for functions that deal in environment
    strings (System.Posix.Env): these use untranslated ByteStrings
    in System.Posix.Environment

  - There is a new function

     System.Posix.ByteString.getArgs :: [ByteString]

    returning the raw untranslated arguments as passed to exec() when
    the program was started.

2 files changed, 545 insertions, 0 deletions

diff --git a/System/Posix/Process/ByteString.hsc b/System/Posix/Process/ByteString.hsc
new file mode 100644
index 0000000..e7b902e
--- /dev/null
+++ b/System/Posix/Process/ByteString.hsc
@@ -0,0 +1,140 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  System.Posix.Process.ByteString
+-- Copyright   :  (c) The University of Glasgow 2002
+-- License     :  BSD-style (see the file libraries/base/LICENSE)
+-- 
+-- Maintainer  :  libraries@haskell.org
+-- Stability   :  provisional
+-- Portability :  non-portable (requires POSIX)
+--
+-- POSIX process support.  See also the System.Cmd and System.Process
+-- modules in the process package.
+--
+-----------------------------------------------------------------------------
+
+module System.Posix.Process.ByteString (
+    -- * Processes
+
+    -- ** Forking and executing
+#ifdef __GLASGOW_HASKELL__
+    forkProcess,
+#endif
+    executeFile,
+    
+    -- ** Exiting
+    exitImmediately,
+
+    -- ** Process environment
+    getProcessID,
+    getParentProcessID,
+
+    -- ** Process groups
+    getProcessGroupID,
+    getProcessGroupIDOf,
+    createProcessGroupFor,
+    joinProcessGroup,
+    setProcessGroupIDOf,
+
+    -- ** Sessions
+    createSession,
+
+    -- ** Process times
+    ProcessTimes(..),
+    getProcessTimes,
+
+    -- ** Scheduling priority
+    nice,
+    getProcessPriority,
+    getProcessGroupPriority,
+    getUserPriority,
+    setProcessPriority,
+    setProcessGroupPriority,
+    setUserPriority,
+
+    -- ** Process status
+    ProcessStatus(..),
+    getProcessStatus,
+    getAnyProcessStatus,
+    getGroupProcessStatus,
+
+    -- ** Deprecated
+    createProcessGroup,
+    setProcessGroupID,
+
+ ) where
+
+#include "HsUnix.h"
+
+import Foreign
+import System.Posix.Process.Internals
+import System.Posix.Process.Common
+
+import Foreign.C hiding (
+     throwErrnoPath,
+     throwErrnoPathIf,
+     throwErrnoPathIf_,
+     throwErrnoPathIfNull,
+     throwErrnoPathIfMinus1,
+     throwErrnoPathIfMinus1_ )
+
+import Data.ByteString (ByteString)
+import qualified Data.ByteString.Char8 as BC
+
+import System.Posix.ByteString.FilePath
+
+#ifdef __HUGS__
+{-# CFILES cbits/HsUnix.c  #-}
+#endif
+
+-- | @'executeFile' cmd args env@ calls one of the
+--   @execv*@ family, depending on whether or not the current
+--   PATH is to be searched for the command, and whether or not an
+--   environment is provided to supersede the process's current
+--   environment.  The basename (leading directory names suppressed) of
+--   the command is passed to @execv*@ as @arg[0]@;
+--   the argument list passed to 'executeFile' therefore 
+--   begins with @arg[1]@.
+executeFile :: RawFilePath                          -- ^ Command
+            -> Bool			    -- ^ Search PATH?
+            -> [ByteString]                 -- ^ Arguments
+            -> Maybe [(ByteString, ByteString)]     -- ^ Environment
+            -> IO a
+executeFile path search args Nothing = do
+  withFilePath path $ \s ->
+    withMany withFilePath (path:args) $ \cstrs ->
+      withArray0 nullPtr cstrs $ \arr -> do
+	pPrPr_disableITimers
+	if search 
+	   then throwErrnoPathIfMinus1_ "executeFile" path (c_execvp s arr)
+	   else throwErrnoPathIfMinus1_ "executeFile" path (c_execv s arr)
+        return undefined -- never reached
+
+executeFile path search args (Just env) = do
+  withFilePath path $ \s ->
+    withMany withFilePath (path:args) $ \cstrs ->
+      withArray0 nullPtr cstrs $ \arg_arr ->
+    let env' = map (\ (name, val) -> name `BC.append` ('=' `BC.cons` val)) env in
+    withMany withFilePath env' $ \cenv ->
+      withArray0 nullPtr cenv $ \env_arr -> do
+	pPrPr_disableITimers
+	if search 
+	   then throwErrnoPathIfMinus1_ "executeFile" path
+		   (c_execvpe s arg_arr env_arr)
+	   else throwErrnoPathIfMinus1_ "executeFile" path
+		   (c_execve s arg_arr env_arr)
+        return undefined -- never reached
+
+foreign import ccall unsafe "execvp"
+  c_execvp :: CString -> Ptr CString -> IO CInt
+
+foreign import ccall unsafe "execv"
+  c_execv :: CString -> Ptr CString -> IO CInt
+
+foreign import ccall unsafe "execve"
+  c_execve :: CString -> Ptr CString -> Ptr CString -> IO CInt
+
diff --git a/System/Posix/Process/Common.hsc b/System/Posix/Process/Common.hsc
new file mode 100644
index 0000000..1e7299f
--- /dev/null
+++ b/System/Posix/Process/Common.hsc
@@ -0,0 +1,405 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+#if __GLASGOW_HASKELL__ >= 701
+{-# LANGUAGE Trustworthy #-}
+#endif
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  System.Posix.Process.Common
+-- Copyright   :  (c) The University of Glasgow 2002
+-- License     :  BSD-style (see the file libraries/base/LICENSE)
+-- 
+-- Maintainer  :  libraries@haskell.org
+-- Stability   :  provisional
+-- Portability :  non-portable (requires POSIX)
+--
+-- POSIX process support.  See also the System.Cmd and System.Process
+-- modules in the process package.
+--
+-----------------------------------------------------------------------------
+
+module System.Posix.Process.Common (
+    -- * Processes
+
+    -- ** Forking and executing
+#ifdef __GLASGOW_HASKELL__
+    forkProcess,
+#endif
+
+    -- ** Exiting
+    exitImmediately,
+
+    -- ** Process environment
+    getProcessID,
+    getParentProcessID,
+
+    -- ** Process groups
+    getProcessGroupID,
+    getProcessGroupIDOf,
+    createProcessGroupFor,
+    joinProcessGroup,
+    setProcessGroupIDOf,
+
+    -- ** Sessions
+    createSession,
+
+    -- ** Process times
+    ProcessTimes(..),
+    getProcessTimes,
+
+    -- ** Scheduling priority
+    nice,
+    getProcessPriority,
+    getProcessGroupPriority,
+    getUserPriority,
+    setProcessPriority,
+    setProcessGroupPriority,
+    setUserPriority,
+
+    -- ** Process status
+    ProcessStatus(..),
+    getProcessStatus,
+    getAnyProcessStatus,
+    getGroupProcessStatus,
+
+    -- ** Deprecated
+    createProcessGroup,
+    setProcessGroupID,
+
+ ) where
+
+#include "HsUnix.h"
+
+import Foreign.C.Error
+import Foreign.C.Types
+import Foreign.Marshal.Alloc ( alloca, allocaBytes )
+import Foreign.Ptr ( Ptr )
+import Foreign.StablePtr ( StablePtr, newStablePtr, freeStablePtr )
+import Foreign.Storable ( Storable(..) )
+import System.Exit
+import System.Posix.Process.Internals
+import System.Posix.Types
+import Control.Monad
+
+#ifdef __GLASGOW_HASKELL__
+import GHC.TopHandler	( runIO )
+#endif
+
+#ifdef __HUGS__
+{-# CFILES cbits/HsUnix.c  #-}
+#endif
+
+-- -----------------------------------------------------------------------------
+-- Process environment
+
+-- | 'getProcessID' calls @getpid@ to obtain the 'ProcessID' for
+--   the current process.
+getProcessID :: IO ProcessID
+getProcessID = c_getpid
+
+foreign import ccall unsafe "getpid"
+   c_getpid :: IO CPid
+
+-- | 'getProcessID' calls @getppid@ to obtain the 'ProcessID' for
+--   the parent of the current process.
+getParentProcessID :: IO ProcessID
+getParentProcessID = c_getppid
+
+foreign import ccall unsafe "getppid"
+  c_getppid :: IO CPid
+
+-- | 'getProcessGroupID' calls @getpgrp@ to obtain the
+--   'ProcessGroupID' for the current process.
+getProcessGroupID :: IO ProcessGroupID
+getProcessGroupID = c_getpgrp
+
+foreign import ccall unsafe "getpgrp"
+  c_getpgrp :: IO CPid
+
+-- | @'getProcessGroupIDOf' pid@ calls @getpgid@ to obtain the
+--   'ProcessGroupID' for process @pid@.
+getProcessGroupIDOf :: ProcessID -> IO ProcessGroupID
+getProcessGroupIDOf pid =
+  throwErrnoIfMinus1 "getProcessGroupIDOf" (c_getpgid pid)
+
+foreign import ccall unsafe "getpgid"
+  c_getpgid :: CPid -> IO CPid
+
+{-
+   To be added in the future, after the deprecation period for the
+   existing createProcessGroup has elapsed:
+
+-- | 'createProcessGroup' calls @setpgid(0,0)@ to make
+--   the current process a new process group leader.
+createProcessGroup :: IO ProcessGroupID
+createProcessGroup = do
+  throwErrnoIfMinus1_ "createProcessGroup" (c_setpgid 0 0)
+  pgid <- getProcessGroupID
+  return pgid
+-}
+
+-- | @'createProcessGroupFor' pid@ calls @setpgid@ to make
+--   process @pid@ a new process group leader.
+createProcessGroupFor :: ProcessID -> IO ProcessGroupID
+createProcessGroupFor pid = do
+  throwErrnoIfMinus1_ "createProcessGroupFor" (c_setpgid pid 0)
+  return pid
+
+-- | @'joinProcessGroup' pgid@ calls @setpgid@ to set the
+--   'ProcessGroupID' of the current process to @pgid@.
+joinProcessGroup :: ProcessGroupID -> IO ()
+joinProcessGroup pgid =
+  throwErrnoIfMinus1_ "joinProcessGroup" (c_setpgid 0 pgid)
+
+{-
+   To be added in the future, after the deprecation period for the
+   existing setProcessGroupID has elapsed:
+
+-- | @'setProcessGroupID' pgid@ calls @setpgid@ to set the
+--   'ProcessGroupID' of the current process to @pgid@.
+setProcessGroupID :: ProcessGroupID -> IO ()
+setProcessGroupID pgid =
+  throwErrnoIfMinus1_ "setProcessGroupID" (c_setpgid 0 pgid)
+-}
+
+-- | @'setProcessGroupIDOf' pid pgid@ calls @setpgid@ to set the
+--   'ProcessGroupIDOf' for process @pid@ to @pgid@.
+setProcessGroupIDOf :: ProcessID -> ProcessGroupID -> IO ()
+setProcessGroupIDOf pid pgid =
+  throwErrnoIfMinus1_ "setProcessGroupIDOf" (c_setpgid pid pgid)
+
+foreign import ccall unsafe "setpgid"
+  c_setpgid :: CPid -> CPid -> IO CInt
+
+-- | 'createSession' calls @setsid@ to create a new session
+--   with the current process as session leader.
+createSession :: IO ProcessGroupID
+createSession = throwErrnoIfMinus1 "createSession" c_setsid
+
+foreign import ccall unsafe "setsid"
+  c_setsid :: IO CPid
+
+-- -----------------------------------------------------------------------------
+-- Process times
+
+-- All times in clock ticks (see getClockTick)
+
+data ProcessTimes
+  = ProcessTimes { elapsedTime     :: ClockTick
+  		 , userTime        :: ClockTick
+		 , systemTime      :: ClockTick
+		 , childUserTime   :: ClockTick
+		 , childSystemTime :: ClockTick
+		 }
+
+-- | 'getProcessTimes' calls @times@ to obtain time-accounting
+--   information for the current process and its children.
+getProcessTimes :: IO ProcessTimes
+getProcessTimes = do
+   allocaBytes (#const sizeof(struct tms)) $ \p_tms -> do
+     elapsed <- throwErrnoIfMinus1 "getProcessTimes" (c_times p_tms)
+     ut  <- (#peek struct tms, tms_utime)  p_tms
+     st  <- (#peek struct tms, tms_stime)  p_tms
+     cut <- (#peek struct tms, tms_cutime) p_tms
+     cst <- (#peek struct tms, tms_cstime) p_tms
+     return (ProcessTimes{ elapsedTime     = elapsed,
+	 		   userTime        = ut,
+	 		   systemTime      = st,
+	 		   childUserTime   = cut,
+	 		   childSystemTime = cst
+			  })
+
+type CTms = ()
+
+foreign import ccall unsafe "__hsunix_times"
+  c_times :: Ptr CTms -> IO CClock
+
+-- -----------------------------------------------------------------------------
+-- Process scheduling priority
+
+nice :: Int -> IO ()
+nice prio = do
+  resetErrno
+  res <- c_nice (fromIntegral prio)
+  when (res == -1) $ do
+    err <- getErrno
+    when (err /= eOK) (throwErrno "nice")
+
+foreign import ccall unsafe "nice"
+  c_nice :: CInt -> IO CInt
+
+getProcessPriority      :: ProcessID      -> IO Int
+getProcessGroupPriority :: ProcessGroupID -> IO Int
+getUserPriority         :: UserID         -> IO Int
+
+getProcessPriority pid = do
+  r <- throwErrnoIfMinus1 "getProcessPriority" $
+         c_getpriority (#const PRIO_PROCESS) (fromIntegral pid)
+  return (fromIntegral r)
+
+getProcessGroupPriority pid = do
+  r <- throwErrnoIfMinus1 "getProcessPriority" $
+         c_getpriority (#const PRIO_PGRP) (fromIntegral pid)
+  return (fromIntegral r)
+
+getUserPriority uid = do
+  r <- throwErrnoIfMinus1 "getUserPriority" $
+         c_getpriority (#const PRIO_USER) (fromIntegral uid)
+  return (fromIntegral r)
+
+foreign import ccall unsafe "getpriority"
+  c_getpriority :: CInt -> CInt -> IO CInt
+
+setProcessPriority      :: ProcessID      -> Int -> IO ()
+setProcessGroupPriority :: ProcessGroupID -> Int -> IO ()
+setUserPriority         :: UserID         -> Int -> IO ()
+
+setProcessPriority pid val = 
+  throwErrnoIfMinus1_ "setProcessPriority" $
+    c_setpriority (#const PRIO_PROCESS) (fromIntegral pid) (fromIntegral val)
+
+setProcessGroupPriority pid val =
+  throwErrnoIfMinus1_ "setProcessPriority" $
+    c_setpriority (#const PRIO_PGRP) (fromIntegral pid) (fromIntegral val)
+
+setUserPriority uid val =
+  throwErrnoIfMinus1_ "setUserPriority" $
+    c_setpriority (#const PRIO_USER) (fromIntegral uid) (fromIntegral val)
+
+foreign import ccall unsafe "setpriority"
+  c_setpriority :: CInt -> CInt -> CInt -> IO CInt
+
+-- -----------------------------------------------------------------------------
+-- Forking, execution
+
+#ifdef __GLASGOW_HASKELL__
+{- | 'forkProcess' corresponds to the POSIX @fork@ system call.
+The 'IO' action passed as an argument is executed in the child process; no other
+threads will be copied to the child process.
+On success, 'forkProcess' returns the child's 'ProcessID' to the parent process;
+in case of an error, an exception is thrown.
+
+'forkProcess' comes with a giant warning: since any other running
+threads are not copied into the child process, it's easy to go wrong:
+e.g. by accessing some shared resource that was held by another thread
+in the parent.
+
+GHC note: 'forkProcess' is not currently supported when using multiple
+processors (@+RTS -N@), although it is supported with @-threaded@ as
+long as only one processor is being used.
+-}
+
+forkProcess :: IO () -> IO ProcessID
+forkProcess action = do
+  stable <- newStablePtr (runIO action)
+  pid <- throwErrnoIfMinus1 "forkProcess" (forkProcessPrim stable)
+  freeStablePtr stable
+  return pid
+
+foreign import ccall "forkProcess" forkProcessPrim :: StablePtr (IO ()) -> IO CPid
+#endif /* __GLASGOW_HASKELL__ */
+
+-- -----------------------------------------------------------------------------
+-- Waiting for process termination
+
+-- | @'getProcessStatus' blk stopped pid@ calls @waitpid@, returning
+--   @'Just' tc@, the 'ProcessStatus' for process @pid@ if it is
+--   available, 'Nothing' otherwise.  If @blk@ is 'False', then
+--   @WNOHANG@ is set in the options for @waitpid@, otherwise not.
+--   If @stopped@ is 'True', then @WUNTRACED@ is set in the
+--   options for @waitpid@, otherwise not.
+getProcessStatus :: Bool -> Bool -> ProcessID -> IO (Maybe ProcessStatus)
+getProcessStatus block stopped pid =
+  alloca $ \wstatp -> do
+    pid' <- throwErrnoIfMinus1Retry "getProcessStatus"
+		(c_waitpid pid wstatp (waitOptions block stopped))
+    case pid' of
+      0  -> return Nothing
+      _  -> do ps <- readWaitStatus wstatp
+	       return (Just ps)
+
+-- safe, because this call might block
+foreign import ccall safe "waitpid"
+  c_waitpid :: CPid -> Ptr CInt -> CInt -> IO CPid
+
+-- | @'getGroupProcessStatus' blk stopped pgid@ calls @waitpid@,
+--   returning @'Just' (pid, tc)@, the 'ProcessID' and
+--   'ProcessStatus' for any process in group @pgid@ if one is
+--   available, 'Nothing' otherwise.  If @blk@ is 'False', then
+--   @WNOHANG@ is set in the options for @waitpid@, otherwise not.
+--   If @stopped@ is 'True', then @WUNTRACED@ is set in the
+--   options for @waitpid@, otherwise not.
+getGroupProcessStatus :: Bool
+                      -> Bool
+                      -> ProcessGroupID
+                      -> IO (Maybe (ProcessID, ProcessStatus))
+getGroupProcessStatus block stopped pgid =
+  alloca $ \wstatp -> do
+    pid <- throwErrnoIfMinus1Retry "getGroupProcessStatus"
+		(c_waitpid (-pgid) wstatp (waitOptions block stopped))
+    case pid of
+      0  -> return Nothing
+      _  -> do ps <- readWaitStatus wstatp
+	       return (Just (pid, ps))
+-- | @'getAnyProcessStatus' blk stopped@ calls @waitpid@, returning
+--   @'Just' (pid, tc)@, the 'ProcessID' and 'ProcessStatus' for any
+--   child process if one is available, 'Nothing' otherwise.  If
+--   @blk@ is 'False', then @WNOHANG@ is set in the options for
+--   @waitpid@, otherwise not.  If @stopped@ is 'True', then
+--   @WUNTRACED@ is set in the options for @waitpid@, otherwise not.
+getAnyProcessStatus :: Bool -> Bool -> IO (Maybe (ProcessID, ProcessStatus))
+getAnyProcessStatus block stopped = getGroupProcessStatus block stopped 1
+
+waitOptions :: Bool -> Bool -> CInt
+--             block   stopped
+waitOptions False False = (#const WNOHANG)
+waitOptions False True  = (#const (WNOHANG|WUNTRACED))
+waitOptions True  False = 0
+waitOptions True  True  = (#const WUNTRACED)
+
+-- Turn a (ptr to a) wait status into a ProcessStatus
+
+readWaitStatus :: Ptr CInt -> IO ProcessStatus
+readWaitStatus wstatp = do
+  wstat <- peek wstatp
+  decipherWaitStatus wstat
+
+-- -----------------------------------------------------------------------------
+-- Exiting
+
+-- | @'exitImmediately' status@ calls @_exit@ to terminate the process
+--   with the indicated exit @status@.
+--   The operation never returns.
+exitImmediately :: ExitCode -> IO ()
+exitImmediately exitcode = c_exit (exitcode2Int exitcode)
+  where
+    exitcode2Int ExitSuccess = 0
+    exitcode2Int (ExitFailure n) = fromIntegral n
+
+foreign import ccall unsafe "exit"
+  c_exit :: CInt -> IO ()
+
+-- -----------------------------------------------------------------------------
+-- Deprecated or subject to change
+
+{-# DEPRECATED createProcessGroup "This function is scheduled to be replaced by something different in the future, we therefore recommend that you do not use this version and use createProcessGroupFor instead." #-}
+-- | @'createProcessGroup' pid@ calls @setpgid@ to make
+--   process @pid@ a new process group leader.
+--   This function is currently deprecated,
+--   and might be changed to making the current
+--   process a new process group leader in future versions.
+createProcessGroup :: ProcessID -> IO ProcessGroupID
+createProcessGroup pid = do
+  throwErrnoIfMinus1_ "createProcessGroup" (c_setpgid pid 0)
+  return pid
+
+{-# DEPRECATED setProcessGroupID "This function is scheduled to be replaced by something different in the future, we therefore recommend that you do not use this version and use setProcessGroupIdOf instead." #-}
+-- | @'setProcessGroupID' pid pgid@ calls @setpgid@ to set the
+--   'ProcessGroupID' for process @pid@ to @pgid@.
+--   This function is currently deprecated,
+--   and might be changed to setting the 'ProcessGroupID'
+--   for the current process in future versions.
+setProcessGroupID :: ProcessID -> ProcessGroupID -> IO ()
+setProcessGroupID pid pgid =
+  throwErrnoIfMinus1_ "setProcessGroupID" (c_setpgid pid pgid)
+
+-- -----------------------------------------------------------------------------