#if __GLASGOW_HASKELL__ >= 709
{-# LANGUAGE Safe #-}
#else
{-# LANGUAGE Trustworthy #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module      :  System.Posix.Process
-- 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 (
    -- * Processes

    -- ** Forking and executing
    forkProcess,
    forkProcessWithUnmask,
    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 Foreign.C
import System.Posix.Process.Internals
import System.Posix.Process.Common
import System.Posix.Internals ( withFilePath )

-- | @'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 :: FilePath                     -- ^ Command
            -> Bool                         -- ^ Search PATH?
            -> [String]                     -- ^ Arguments
            -> Maybe [(String, String)]     -- ^ 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 ++ ('=' : 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