Fix bug where openFile in WriteMode truncates the file even if the
open fails because of a locking violation.
#undef DEBUG
-- -----------------------------------------------------------------------------
#undef DEBUG
-- -----------------------------------------------------------------------------
--- $Id: PrelHandle.hsc,v 1.11 2001/06/29 12:45:39 simonmar Exp $
+-- $Id: PrelHandle.hsc,v 1.12 2001/06/29 13:41:43 simonmar Exp $
--
-- (c) The University of Glasgow, 1994-2001
--
--
-- (c) The University of Glasgow, 1994-2001
--
ReadWriteMode -> rw_flags
AppendMode -> append_flags
ReadWriteMode -> rw_flags
AppendMode -> append_flags
+ truncate | WriteMode <- mode = True
+ | otherwise = False
+
binary_flags
#ifdef HAVE_O_BINARY
| binary = o_BINARY
binary_flags
#ifdef HAVE_O_BINARY
| binary = o_BINARY
throwErrnoIfMinus1Retry "openFile"
(c_open f (fromIntegral oflags) 0o666)
throwErrnoIfMinus1Retry "openFile"
(c_open f (fromIntegral oflags) 0o666)
- openFd fd filepath mode binary
+ openFd fd filepath mode binary truncate
+ -- ASSERT: if we just created the file, then openFd won't fail
+ -- (so we don't need to worry about removing the newly created file
+ -- in the event of an error).
std_flags = o_NONBLOCK .|. o_NOCTTY
output_flags = std_flags .|. o_CREAT
read_flags = std_flags .|. o_RDONLY
std_flags = o_NONBLOCK .|. o_NOCTTY
output_flags = std_flags .|. o_CREAT
read_flags = std_flags .|. o_RDONLY
-write_flags = output_flags .|. o_WRONLY .|. o_TRUNC
+write_flags = output_flags .|. o_WRONLY
rw_flags = output_flags .|. o_RDWR
rw_flags = output_flags .|. o_RDWR
-append_flags = output_flags .|. o_WRONLY .|. o_APPEND
+append_flags = write_flags .|. o_APPEND
-- ---------------------------------------------------------------------------
-- openFd
-- ---------------------------------------------------------------------------
-- openFd
-openFd :: FD -> FilePath -> IOMode -> Bool -> IO Handle
-openFd fd filepath mode binary = do
+openFd :: FD -> FilePath -> IOMode -> Bool -> Bool -> IO Handle
+openFd fd filepath mode binary truncate = do
-- turn on non-blocking mode
setNonBlockingFD fd
-- turn on non-blocking mode
setNonBlockingFD fd
when (r == -1) $
ioException (IOError Nothing ResourceBusy "openFile"
"file is locked" Nothing)
when (r == -1) $
ioException (IOError Nothing ResourceBusy "openFile"
"file is locked" Nothing)
+
+ -- truncate the file if necessary
+ when truncate (fileTruncate filepath)
+
mkFileHandle fd filepath ha_type binary
mkFileHandle fd filepath ha_type binary
{-# OPTIONS -fno-implicit-prelude -optc-DNON_POSIX_SOURCE #-}
-- ---------------------------------------------------------------------------
{-# OPTIONS -fno-implicit-prelude -optc-DNON_POSIX_SOURCE #-}
-- ---------------------------------------------------------------------------
--- $Id: PrelPosix.hsc,v 1.7 2001/06/22 12:36:34 rrt Exp $
+-- $Id: PrelPosix.hsc,v 1.8 2001/06/29 13:41:43 simonmar Exp $
--
-- POSIX support layer for the standard libraries
--
--
-- POSIX support layer for the standard libraries
--
s_issock :: CMode -> Bool
s_issock cmode = False
#endif
s_issock :: CMode -> Bool
s_issock cmode = False
#endif
+
+-- It isn't clear whether ftruncate is POSIX or not (I've read several
+-- manpages and they seem to conflict), so we truncate using open/2.
+fileTruncate :: FilePath -> IO ()
+fileTruncate file = do
+ let flags = o_WRONLY .|. o_TRUNC
+ withCString file $ \file_cstr -> do
+ fd <- fromIntegral `liftM`
+ throwErrnoIfMinus1Retry "fileTruncate"
+ (c_open file_cstr (fromIntegral flags) 0o666)
+ c_close fd
+ return ()
+
-- ---------------------------------------------------------------------------
-- Terminal-related stuff
-- ---------------------------------------------------------------------------
-- Terminal-related stuff
foreign import "tcsetattr" unsafe
c_tcsetattr :: CInt -> CInt -> Ptr Termios -> IO CInt
foreign import "tcsetattr" unsafe
c_tcsetattr :: CInt -> CInt -> Ptr Termios -> IO CInt
+foreign import "unlink" unsafe
+ c_unlink :: CString -> IO CInt
+
foreign import "waitpid" unsafe
c_waitpid :: CPid -> Ptr CInt -> CInt -> IO CPid
#endif
foreign import "waitpid" unsafe
c_waitpid :: CPid -> Ptr CInt -> CInt -> IO CPid
#endif