{-# OPTIONS_GHC -fno-implicit-prelude #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  System.Posix.Internals
-- Copyright   :  (c) The University of Glasgow, 1992-2002
-- License     :  see libraries/base/LICENSE
-- 
-- Maintainer  :  cvs-ghc@haskell.org
-- Stability   :  internal
-- Portability :  non-portable
--
-- POSIX support layer for the standard libraries.
-- This library is built on *every* platform, including Win32.
--
-- Non-posix compliant in order to support the following features:
--	* S_ISSOCK (no sockets in POSIX)
--
-----------------------------------------------------------------------------

-- #hide
module System.Posix.Internals where

import Control.Monad
import System.Posix.Types

import Foreign
import Foreign.C

import Data.Bits
import Data.Maybe

import System.IO

import Hugs.Prelude (IOException(..), IOErrorType(..))

{-# CFILES cbits/PrelIOUtils.c cbits/dirUtils.c cbits/consUtils.c #-}

-- ---------------------------------------------------------------------------
-- Types

type CDir       = ()
type CDirent    = ()
type CFLock     = ()
type CGroup     = ()
type CLconv     = ()
type CPasswd    = ()
type CSigaction = ()
type CSigset    = ()
type CStat      = ()
type CTermios   = ()
type CTm	= ()
type CTms	= ()
type CUtimbuf   = ()
type CUtsname   = ()

type FD = Int

-- ---------------------------------------------------------------------------
-- stat()-related stuff

fdFileSize :: Int -> IO Integer
fdFileSize fd = 
  allocaBytes sizeof_stat $ \ p_stat -> do
    throwErrnoIfMinus1Retry "fileSize" $
	c_fstat (fromIntegral fd) p_stat
    c_mode <- st_mode p_stat :: IO CMode 
    if not (s_isreg c_mode)
	then return (-1)
	else do
    c_size <- st_size p_stat :: IO COff
    return (fromIntegral c_size)

data FDType  = Directory | Stream | RegularFile
	       deriving (Eq)

fileType :: FilePath -> IO FDType
fileType file =
  allocaBytes sizeof_stat $ \ p_stat -> do
  withCString file $ \p_file -> do
    throwErrnoIfMinus1Retry "fileType" $
      c_stat p_file p_stat
    statGetType p_stat

-- NOTE: On Win32 platforms, this will only work with file descriptors
-- referring to file handles. i.e., it'll fail for socket FDs.
fdType :: Int -> IO FDType
fdType fd = 
  allocaBytes sizeof_stat $ \ p_stat -> do
    throwErrnoIfMinus1Retry "fdType" $
	c_fstat (fromIntegral fd) p_stat
    statGetType p_stat

statGetType p_stat = do
  c_mode <- st_mode p_stat :: IO CMode
  case () of
      _ | s_isdir c_mode    	-> return Directory
        | s_isfifo c_mode || s_issock c_mode || s_ischr  c_mode
			  	-> return Stream
	| s_isreg c_mode	-> return RegularFile
	| otherwise		-> ioError ioe_unknownfiletype
    

ioe_unknownfiletype = IOError Nothing UnsupportedOperation "fdType"
			"unknown file type" Nothing

fdGetMode :: Int -> IO IOMode
fdGetMode fd = do

    flags <- throwErrnoIfMinus1Retry "fdGetMode" 
		(c_fcntl_read (fromIntegral fd) const_f_getfl)

    let
       wH  = (flags .&. o_WRONLY) /= 0
       aH  = (flags .&. o_APPEND) /= 0
       rwH = (flags .&. o_RDWR) /= 0

       mode
	 | wH && aH  = AppendMode
	 | wH        = WriteMode
	 | rwH       = ReadWriteMode
	 | otherwise = ReadMode
	  
    return mode

-- ---------------------------------------------------------------------------
-- Terminal-related stuff

fdIsTTY :: Int -> IO Bool
fdIsTTY fd = c_isatty (fromIntegral fd) >>= return.toBool

setEcho :: Int -> Bool -> IO ()
setEcho fd on = do
  tcSetAttr fd $ \ p_tios -> do
    c_lflag <- c_lflag p_tios :: IO CTcflag
    let new_c_lflag
	 | on        = c_lflag .|. fromIntegral const_echo
	 | otherwise = c_lflag .&. complement (fromIntegral const_echo)
    poke_c_lflag p_tios (new_c_lflag :: CTcflag)

getEcho :: Int -> IO Bool
getEcho fd = do
  tcSetAttr fd $ \ p_tios -> do
    c_lflag <- c_lflag p_tios :: IO CTcflag
    return ((c_lflag .&. fromIntegral const_echo) /= 0)

setCooked :: Int -> Bool -> IO ()
setCooked fd cooked = 
  tcSetAttr fd $ \ p_tios -> do

    -- turn on/off ICANON
    c_lflag <- c_lflag p_tios :: IO CTcflag
    let new_c_lflag | cooked    = c_lflag .|. (fromIntegral const_icanon)
	            | otherwise = c_lflag .&. complement (fromIntegral const_icanon)
    poke_c_lflag p_tios (new_c_lflag :: CTcflag)

    -- set VMIN & VTIME to 1/0 respectively
    when (not cooked) $ do
            c_cc <- ptr_c_cc p_tios
	    let vmin  = (c_cc `plusPtr` (fromIntegral const_vmin))  :: Ptr Word8
		vtime = (c_cc `plusPtr` (fromIntegral const_vtime)) :: Ptr Word8
	    poke vmin  1
	    poke vtime 0

tcSetAttr :: FD -> (Ptr CTermios -> IO a) -> IO a
tcSetAttr fd fun = do
     allocaBytes sizeof_termios  $ \p_tios -> do
	throwErrnoIfMinus1Retry "tcSetAttr"
	   (c_tcgetattr (fromIntegral fd) p_tios)

	-- tcsetattr() when invoked by a background process causes the process
	-- to be sent SIGTTOU regardless of whether the process has TOSTOP set
	-- in its terminal flags (try it...).  This function provides a
	-- wrapper which temporarily blocks SIGTTOU around the call, making it
	-- transparent.
	allocaBytes sizeof_sigset_t $ \ p_sigset -> do
	allocaBytes sizeof_sigset_t $ \ p_old_sigset -> do
	     c_sigemptyset p_sigset
	     c_sigaddset   p_sigset const_sigttou
	     c_sigprocmask const_sig_block p_sigset p_old_sigset
	     r <- fun p_tios  -- do the business
	     throwErrnoIfMinus1Retry_ "tcSetAttr" $
		 c_tcsetattr (fromIntegral fd) const_tcsanow p_tios
	     c_sigprocmask const_sig_setmask p_old_sigset nullPtr
	     return r

-- ---------------------------------------------------------------------------
-- Turning on non-blocking for a file descriptor

setNonBlockingFD fd = do
  flags <- throwErrnoIfMinus1Retry "setNonBlockingFD"
		 (c_fcntl_read (fromIntegral fd) const_f_getfl)
  -- An error when setting O_NONBLOCK isn't fatal: on some systems 
  -- there are certain file handles on which this will fail (eg. /dev/null
  -- on FreeBSD) so we throw away the return code from fcntl_write.
  unless (testBit flags (fromIntegral o_NONBLOCK)) $ do
    c_fcntl_write (fromIntegral fd) const_f_setfl (flags .|. o_NONBLOCK)
    return ()

-- -----------------------------------------------------------------------------
-- foreign imports

foreign import ccall unsafe "HsBase.h access"
   c_access :: CString -> CMode -> IO CInt

foreign import ccall unsafe "HsBase.h chmod"
   c_chmod :: CString -> CMode -> IO CInt

foreign import ccall unsafe "HsBase.h chdir"
   c_chdir :: CString -> IO CInt

foreign import ccall unsafe "HsBase.h close"
   c_close :: CInt -> IO CInt

foreign import ccall unsafe "HsBase.h closedir" 
   c_closedir :: Ptr CDir -> IO CInt

foreign import ccall unsafe "HsBase.h creat"
   c_creat :: CString -> CMode -> IO CInt

foreign import ccall unsafe "HsBase.h dup"
   c_dup :: CInt -> IO CInt

foreign import ccall unsafe "HsBase.h dup2"
   c_dup2 :: CInt -> CInt -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_fstat"
   c_fstat :: CInt -> Ptr CStat -> IO CInt

foreign import ccall unsafe "HsBase.h getcwd"
   c_getcwd   :: Ptr CChar -> CInt -> IO (Ptr CChar)

foreign import ccall unsafe "HsBase.h isatty"
   c_isatty :: CInt -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_lseek"
   c_lseek :: CInt -> COff -> CInt -> IO COff

foreign import ccall unsafe "HsBase.h __hscore_lstat"
   lstat :: CString -> Ptr CStat -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_open"
   c_open :: CString -> CInt -> CMode -> IO CInt

foreign import ccall unsafe "HsBase.h opendir" 
   c_opendir :: CString  -> IO (Ptr CDir)

foreign import ccall unsafe "HsBase.h __hscore_mkdir"
   mkdir :: CString -> CInt -> IO CInt

foreign import ccall unsafe "HsBase.h read" 
   c_read :: CInt -> Ptr CChar -> CSize -> IO CSsize

foreign import ccall unsafe "dirUtils.h __hscore_renameFile"
   c_rename :: CString -> CString -> IO CInt
		     
foreign import ccall unsafe "HsBase.h rewinddir"
   c_rewinddir :: Ptr CDir -> IO ()

foreign import ccall unsafe "HsBase.h rmdir"
   c_rmdir :: CString -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_stat"
   c_stat :: CString -> Ptr CStat -> IO CInt

foreign import ccall unsafe "HsBase.h umask"
   c_umask :: CMode -> IO CMode

foreign import ccall unsafe "HsBase.h write" 
   c_write :: CInt -> Ptr CChar -> CSize -> IO CSsize

foreign import ccall unsafe "HsBase.h __hscore_ftruncate"
   c_ftruncate :: CInt -> COff -> IO CInt

foreign import ccall unsafe "HsBase.h unlink"
   c_unlink :: CString -> IO CInt

foreign import ccall unsafe "HsBase.h getpid"
   c_getpid :: IO CPid

foreign import ccall unsafe "HsBase.h fcntl"
   c_fcntl_read  :: CInt -> CInt -> IO CInt

foreign import ccall unsafe "HsBase.h fcntl"
   c_fcntl_write :: CInt -> CInt -> CInt -> IO CInt

foreign import ccall unsafe "HsBase.h fcntl"
   c_fcntl_lock  :: CInt -> CInt -> Ptr CFLock -> IO CInt

foreign import ccall unsafe "HsBase.h fork"
   c_fork :: IO CPid 

foreign import ccall unsafe "HsBase.h link"
   c_link :: CString -> CString -> IO CInt

foreign import ccall unsafe "HsBase.h mkfifo"
   c_mkfifo :: CString -> CMode -> IO CInt

foreign import ccall unsafe "HsBase.h pipe"
   c_pipe :: Ptr CInt -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_sigemptyset"
   c_sigemptyset :: Ptr CSigset -> IO CInt

foreign import ccall unsafe "HsBase.h __hscore_sigaddset"
   c_sigaddset :: Ptr CSigset -> CInt -> IO CInt

foreign import ccall unsafe "HsBase.h sigprocmask"
   c_sigprocmask :: CInt -> Ptr CSigset -> Ptr CSigset -> IO CInt

foreign import ccall unsafe "HsBase.h tcgetattr"
   c_tcgetattr :: CInt -> Ptr CTermios -> IO CInt

foreign import ccall unsafe "HsBase.h tcsetattr"
   c_tcsetattr :: CInt -> CInt -> Ptr CTermios -> IO CInt

foreign import ccall unsafe "HsBase.h utime"
   c_utime :: CString -> Ptr CUtimbuf -> IO CMode

foreign import ccall unsafe "HsBase.h waitpid"
   c_waitpid :: CPid -> Ptr CInt -> CInt -> IO CPid

-- traversing directories
foreign import ccall unsafe "dirUtils.h __hscore_readdir"
  readdir  :: Ptr CDir -> Ptr (Ptr CDirent) -> IO CInt
 
foreign import ccall unsafe "HsBase.h __hscore_free_dirent"
  freeDirEnt  :: Ptr CDirent -> IO ()
 
foreign import ccall unsafe "HsBase.h __hscore_end_of_dir"
  end_of_dir :: CInt
 
foreign import ccall unsafe "HsBase.h __hscore_d_name"
  d_name :: Ptr CDirent -> IO CString

-- POSIX flags only:
foreign import ccall unsafe "HsBase.h __hscore_o_rdonly" o_RDONLY :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_wronly" o_WRONLY :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_rdwr"   o_RDWR   :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_append" o_APPEND :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_creat"  o_CREAT  :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_excl"   o_EXCL   :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_trunc"  o_TRUNC  :: CInt

-- non-POSIX flags.
foreign import ccall unsafe "HsBase.h __hscore_o_noctty"   o_NOCTTY   :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_nonblock" o_NONBLOCK :: CInt
foreign import ccall unsafe "HsBase.h __hscore_o_binary"   o_BINARY   :: CInt

foreign import ccall unsafe "HsBase.h __hscore_s_isreg"  s_isreg  :: CMode -> Bool
foreign import ccall unsafe "HsBase.h __hscore_s_ischr"  s_ischr  :: CMode -> Bool
foreign import ccall unsafe "HsBase.h __hscore_s_isblk"  s_isblk  :: CMode -> Bool
foreign import ccall unsafe "HsBase.h __hscore_s_isdir"  s_isdir  :: CMode -> Bool
foreign import ccall unsafe "HsBase.h __hscore_s_isfifo" s_isfifo :: CMode -> Bool

foreign import ccall unsafe "HsBase.h __hscore_sizeof_stat" sizeof_stat :: Int
foreign import ccall unsafe "HsBase.h __hscore_st_mtime" st_mtime :: Ptr CStat -> IO CTime
foreign import ccall unsafe "HsBase.h __hscore_st_size" st_size :: Ptr CStat -> IO COff
foreign import ccall unsafe "HsBase.h __hscore_st_mode" st_mode :: Ptr CStat -> IO CMode

foreign import ccall unsafe "HsBase.h __hscore_echo"         const_echo :: CInt
foreign import ccall unsafe "HsBase.h __hscore_tcsanow"      const_tcsanow :: CInt
foreign import ccall unsafe "HsBase.h __hscore_icanon"       const_icanon :: CInt
foreign import ccall unsafe "HsBase.h __hscore_vmin"         const_vmin   :: CInt
foreign import ccall unsafe "HsBase.h __hscore_vtime"        const_vtime  :: CInt
foreign import ccall unsafe "HsBase.h __hscore_sigttou"      const_sigttou :: CInt
foreign import ccall unsafe "HsBase.h __hscore_sig_block"    const_sig_block :: CInt
foreign import ccall unsafe "HsBase.h __hscore_sig_setmask"  const_sig_setmask :: CInt
foreign import ccall unsafe "HsBase.h __hscore_f_getfl"      const_f_getfl :: CInt
foreign import ccall unsafe "HsBase.h __hscore_f_setfl"      const_f_setfl :: CInt

foreign import ccall unsafe "HsBase.h __hscore_sizeof_termios"  sizeof_termios :: Int
foreign import ccall unsafe "HsBase.h __hscore_sizeof_sigset_t" sizeof_sigset_t :: Int

foreign import ccall unsafe "HsBase.h __hscore_lflag" c_lflag :: Ptr CTermios -> IO CTcflag
foreign import ccall unsafe "HsBase.h __hscore_poke_lflag" poke_c_lflag :: Ptr CTermios -> CTcflag -> IO ()
foreign import ccall unsafe "HsBase.h __hscore_ptr_c_cc" ptr_c_cc  :: Ptr CTermios -> IO (Ptr Word8)

foreign import ccall unsafe "HsBase.h __hscore_s_issock" s_issock :: CMode -> Bool
