It's hard to belive, that nobody ever tackled/solved the subj. problem. I
still can delay a bit solving it, in hope somebody would share experience.
Regards,
Belka
Belka wrote:
>
> Hello, communion people!
>
> I have a problem and ask for an advice.
> I'm dealing with sockets on *Linux* platform (Network.Socket). The problem
> is that I can't fully control timeout for (connect :: Socket -> SockAddr
> -> IO ()) operation.
> On my system the timeout is - 3 seconds - I want to be able to change that
> in run-time. Well I managed to find out how to make it LESS THAN 3 seconds
> - using System.Timeout. But how to make timeout bigger (for example 9
> seconds) is a mystery.
> (Notice: in order to achieve 9 seconds timeout - just repeating *connect*
> 3 times won't be effective for long-slow-way-connections. So it's not a
> solution.)
>
> The source code of Network.Socket.connect, taken from darcs:
> ---------------------------------
> -- Connecting a socket
> --
> -- Make a connection to an already opened socket on a given machine
> -- and port. assumes that we have already called createSocket,
> -- otherwise it will fail.
> --
> -- This is the dual to $bindSocket$. The {\em server} process will
> -- usually bind to a port number, the {\em client} will then connect
> -- to the same port number. Port numbers of user applications are
> -- normally agreed in advance, otherwise we must rely on some meta
> -- protocol for telling the other side what port number we have been
> -- allocated.
>
> connect :: Socket -- Unconnected Socket
> -> SockAddr -- Socket address stuff
> -> IO ()
>
> connect sock@(MkSocket s _family _stype _protocol socketStatus) addr = do
> modifyMVar_ socketStatus $ \currentStatus -> do
> if currentStatus /= NotConnected
> then
> ioError (userError ("connect: can't peform connect on socket in status
> " ++
> show currentStatus))
> else do
> withSockAddr addr $ \p_addr sz -> do
>
> let connectLoop = do
> r <- c_connect s p_addr (fromIntegral sz)
> if r == -1
> then do
> rc <- c_getLastError
> case rc of
> 10093 -> do -- WSANOTINITIALISED
> withSocketsDo (return ())
> r <- c_connect s p_addr (fromIntegral sz)
> if r == -1
> then (c_getLastError >>= throwSocketError "connect")
> else return r
> _ -> throwSocketError "connect" rc
> else return r
>
> connectBlocked = do
> #if !defined(__HUGS__)
> threadWaitWrite (fromIntegral s)
> #endif
> err <- getSocketOption sock SoError
> if (err == 0)
> then return 0
> else do ioError (errnoToIOError "connect"
> (Errno (fromIntegral err))
> Nothing Nothing)
>
> connectLoop
> return Connected
>
> ---------------------------------
> I know that controlling timeout is somehow connected to select(2) (I'm
> currently investigating this matter...), but it's not in the Network or
> Network.Socket libs (but in the libs that they FFI with).
> Hope I won't have to rewrite these low-level functions.... >__<
> Could anybody, please share some experience on how to adjust timeout for
> *connect*?
>
> Thanks in advance,
> Best regards,
> Belka
>
--
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