From 3e4c658909d6b554c405f61f786ddf86151bdd79 Mon Sep 17 00:00:00 2001
From: Kazu Yamamoto <kazu@iij.ad.jp>
Date: Fri, 14 Aug 2026 10:35:41 +0900
Subject: [PATCH] simplifying gracefulClose

---
 Network/Socket/Shutdown.hs | 55 +++-----------------------------------
 1 file changed, 4 insertions(+), 51 deletions(-)

diff --git a/Network/Socket/Shutdown.hs b/Network/Socket/Shutdown.hs
index 92eccb30..0e13b9a6 100644
--- a/Network/Socket/Shutdown.hs
+++ b/Network/Socket/Shutdown.hs
@@ -15,15 +15,9 @@ import Foreign.Marshal.Alloc (mallocBytes, free)
 import qualified System.IO.Error as E
 import System.Timeout
 
-#if !defined(mingw32_HOST_OS)
-import Control.Concurrent.STM
-import qualified GHC.Event as Ev
-#endif
-
 import Network.Socket.Buffer
 import Network.Socket.Imports
 import Network.Socket.Internal
-import Network.Socket.STM
 import Network.Socket.Types
 
 data ShutdownCmd = ShutdownReceive
@@ -58,7 +52,8 @@ foreign import CALLCONV unsafe "shutdown"
 --
 --   Since: 3.1.1.0
 gracefulClose :: Socket -> Int -> IO ()
-gracefulClose s tmout0 = (sendRecvFIN `E.finally` close s) `annotateIOException` show s
+gracefulClose s tmout0 =
+    (sendRecvFIN `E.finally` close s) `annotateIOException` show s
   where
     sendRecvFIN = do
         -- Sending TCP FIN.
@@ -71,18 +66,7 @@ gracefulClose s tmout0 = (sendRecvFIN `E.finally` close s) `annotateIOException`
               -- FIN arrives meanwhile.
               yield
               -- Waiting TCP FIN.
-              E.bracket (mallocBytes bufSize) free (recvEOF s tmout0)
-
-recvEOF :: Socket -> Int -> Ptr Word8 -> IO ()
-#if !defined(mingw32_HOST_OS)
-recvEOF s tmout0 buf = do
-    mevmgr <- Ev.getSystemEventManager
-    case mevmgr of
-      Nothing -> recvEOFtimeout s tmout0 buf
-      Just _ -> recvEOFevent s tmout0 buf
-#else
-recvEOF = recvEOFtimeout
-#endif
+              E.bracket (mallocBytes bufSize) free (recvEOFtimeout s tmout0)
 
 -- Don't use 4092 here. The GHC runtime takes the global lock
 -- if the length is over 3276 bytes in 32bit or 3272 bytes in 64bit.
@@ -90,35 +74,4 @@ bufSize :: Int
 bufSize = 1024
 
 recvEOFtimeout :: Socket -> Int -> Ptr Word8 -> IO ()
-recvEOFtimeout s tmout0 buf = void $ timeout tmout0 $ recvBuf s buf bufSize
-
-#if !defined(mingw32_HOST_OS)
-data Wait = MoreData | TimeoutTripped
-
-recvEOFevent :: Socket -> Int -> Ptr Word8 -> IO ()
-recvEOFevent s tmout0 buf = do
-    tmmgr <- Ev.getSystemTimerManager
-    tvar <- newTVarIO False
-    E.bracket (setupTimeout tmmgr tvar) (cancelTimeout tmmgr) $ \_ -> do
-        E.bracket (setupRead s) cancelRead $ \(rxWait,_) -> do
-            let toWait = readTVar tvar >>= check
-                wait = atomically ((toWait >> return TimeoutTripped)
-                               <|> (rxWait >> return MoreData))
-            waitRes <- wait
-            case waitRes of
-              TimeoutTripped -> return ()
-              -- We don't check the (positive) length.
-              -- In normal case, it's 0. That is, only FIN is received.
-              -- In error cases, data is available. But there is no
-              -- application which can read it. So, let's stop receiving
-              -- to prevent attacks.
-              MoreData       -> void $ recvBufNoWait s buf bufSize
-  where
-    -- millisecond to microsecond
-    tmout = tmout0 * 1000
-    setupTimeout tmmgr tvar =
-        Ev.registerTimeout tmmgr tmout $ atomically $ writeTVar tvar True
-    cancelTimeout = Ev.unregisterTimeout
-    setupRead = waitAndCancelReadSocketSTM
-    cancelRead (_,cancel) = cancel
-#endif
+recvEOFtimeout s tmout0 buf = void $ timeout (tmout0 * 1000) $ recvBuf s buf bufSize