#5797: readRawBufferPtr cannot be interrupted by exception on Windows with
-threaded
-----------------------------------------+----------------------------------
Reporter: joeyadams | Owner:
Type: bug | Status: new
Priority: normal | Component: libraries/base
Version: 7.2.2 | Keywords:
Os: Windows | Architecture: x86
Failure: Incorrect result at runtime | Testcase:
Blockedby: | Blocking:
Related: |
-----------------------------------------+----------------------------------
On Windows, in a program compiled with -threaded, if a thread receives
from a Handle created by the network package (e.g. with hGetLine), it
cannot be interrupted by an asynchronous exception.
I've traced it down to readRawBufferPtr, which is used by
Network.Socket.recv. Although I haven't tested readRawBufferPtr directly,
my test case (attached) tests Network.Socket.recv.
For Windows, base 4.4.1.0 implements it as:
{{{
readRawBufferPtr :: String -> FD -> Ptr Word8 -> Int -> CSize -> IO CInt
readRawBufferPtr loc !fd buf off len
| threaded = blockingReadRawBufferPtr loc fd buf off len
| otherwise = asyncReadRawBufferPtr loc fd buf off len
...
blockingReadRawBufferPtr :: String -> FD -> Ptr Word8 -> Int -> CSize ->
IO CInt
blockingReadRawBufferPtr loc fd buf off len
= fmap fromIntegral $ throwErrnoIfMinus1Retry loc $
if fdIsSocket fd
then c_safe_recv (fdFD fd) (buf `plusPtr` off) len 0
else c_safe_read (fdFD fd) (buf `plusPtr` off) len
...
-- NOTE: "safe" versions of the read/write calls for use by the threaded
RTS.
-- These calls may block, but that's ok.
foreign import stdcall safe "recv"
c_safe_recv :: CInt -> Ptr Word8 -> CSize -> CInt{-flags-} -> IO CSsize
foreign import stdcall safe "send"
c_safe_send :: CInt -> Ptr Word8 -> CSize -> CInt{-flags-} -> IO CSsize
}}}
If I understand correctly, safe foreign calls cannot be interrupted by
asynchronous exceptions.
Is this a bug in readRawBufferPtr, or a bug in the network package? Can a
caller expect readRawBufferPtr to be interruptible by an exception?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5797>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
Glasgow-haskell-bugs mailing list
Glasgow-haskell-bugs@haskell.org
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
