System/Posix/Process/Internals.hs

module System.Posix.Process.Internals (
 pPrPr_disableITimers, c_execvpe,
 decipherWaitStatus, ProcessStatus(..) ) where

import Foreign
import Foreign.C
import System.Exit
import System.IO.Error
import GHC.Conc (Signal)

data ProcessStatus = Exited ExitCode
 | Terminated Signal
 | Stopped Signal
		 deriving (Eq, Ord, Show)

-- this function disables the itimer, which would otherwise cause confusing
-- signals to be sent to the new process.
foreign import ccall unsafe "pPrPr_disableITimers"
 pPrPr_disableITimers :: IO ()

foreign import ccall unsafe "execvpe"
 c_execvpe :: CString -> Ptr CString -> Ptr CString -> IO CInt

decipherWaitStatus :: CInt -> IO ProcessStatus
decipherWaitStatus wstat =
 if c_WIFEXITED wstat /= 0
 then do
 let exitstatus = c_WEXITSTATUS wstat
 if exitstatus == 0
	 then return (Exited ExitSuccess)
	 else return (Exited (ExitFailure (fromIntegral exitstatus)))
 else do
 if c_WIFSIGNALED wstat /= 0
	 then do
		let termsig = c_WTERMSIG wstat
 return (Terminated termsig)
	 else do
		if c_WIFSTOPPED wstat /= 0
		 then do
			let stopsig = c_WSTOPSIG wstat
 return (Stopped stopsig)
		 else do
			ioError (mkIOError illegalOperationErrorType
				 "waitStatus" Nothing Nothing)

foreign import ccall unsafe "__hsunix_wifexited"
 c_WIFEXITED :: CInt -> CInt 

foreign import ccall unsafe "__hsunix_wexitstatus"
 c_WEXITSTATUS :: CInt -> CInt

foreign import ccall unsafe "__hsunix_wifsignaled"
 c_WIFSIGNALED :: CInt -> CInt

foreign import ccall unsafe "__hsunix_wtermsig"
 c_WTERMSIG :: CInt -> CInt 

foreign import ccall unsafe "__hsunix_wifstopped"
 c_WIFSTOPPED :: CInt -> CInt

foreign import ccall unsafe "__hsunix_wstopsig"
 c_WSTOPSIG :: CInt -> CInt