From be2d7718c8964af23c798a7431a7764167e5266e Mon Sep 17 00:00:00 2001
From: hvlad <hvlad@users.sourceforge.net>
Date: Fri, 17 Jan 2020 15:14:53 +0200
Subject: [PATCH] Fixed bug CORE-6231 : access violation on shutdown of xnet
 connection to local database when events have been registered

---
 src/remote/client/interface.cpp |  9 ++++++++-
 src/remote/os/win32/wnet.cpp    | 15 ++++++++++++---
 src/remote/os/win32/xnet.cpp    | 11 +++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/remote/client/interface.cpp b/src/remote/client/interface.cpp
index 18fa388fbb..abb2ecbfda 100644
--- a/src/remote/client/interface.cpp
+++ b/src/remote/client/interface.cpp
@@ -7204,7 +7204,14 @@ static THREAD_ENTRY_DECLARE event_thread(THREAD_ENTRY_PARAM arg)
 		P_OP operation = op_void;
 		{	// scope
 			RefMutexGuard portGuard(*port->port_sync, FB_FUNCTION);
-			stuff = port->receive(&packet);
+			try
+			{
+				stuff = port->receive(&packet);
+			}
+			catch(status_exception&)
+			{
+				// ignore
+			}
 
 			operation = packet.p_operation;
 
diff --git a/src/remote/os/win32/wnet.cpp b/src/remote/os/win32/wnet.cpp
index b551112bd9..11c1fb939c 100644
--- a/src/remote/os/win32/wnet.cpp
+++ b/src/remote/os/win32/wnet.cpp
@@ -759,7 +759,11 @@ static void disconnect(rem_port* port)
 	}
 
 	wnet_ports->unRegisterPort(port);
-	port->release();
+
+	if (port->port_thread_guard && port->port_events_thread && !Thread::isCurrent(port->port_events_threadId))
+		port->port_thread_guard->setWait(port->port_events_thread);
+	else
+		port->release();
 }
 
 
@@ -1332,7 +1336,7 @@ static bool packet_receive(rem_port* port, UCHAR* buffer, SSHORT buffer_length,
 
 	if (!n)
 	{
-		if (port->port_flags & PORT_detached)
+		if (port->port_flags & (PORT_detached | PORT_disconnect))
 			return false;
 
 		return wnet_error(port, "ReadFile end-of-file", isc_net_read_err, dwError);
@@ -1408,10 +1412,15 @@ static bool packet_send( rem_port* port, const SCHAR* buffer, SSHORT buffer_leng
 		status = GetOverlappedResult(port->port_pipe, &ovrl, &n, TRUE);
 		dwError = GetLastError();
 	}
-	if (!status)
+	if (!status && dwError != ERROR_NO_DATA)
 		return wnet_error(port, "WriteFile", isc_net_write_err, dwError);
 	if (n != length)
+	{
+		if (port->port_flags & (PORT_detached | PORT_disconnect))
+			return false;
+
 		return wnet_error(port, "WriteFile truncated", isc_net_write_err, dwError);
+	}
 
 #if defined(DEBUG) && defined(WNET_trace)
 	packet_print("send", reinterpret_cast<const UCHAR*>(buffer), buffer_length);
diff --git a/src/remote/os/win32/xnet.cpp b/src/remote/os/win32/xnet.cpp
index 7385d0c09e..482f14a1f4 100644
--- a/src/remote/os/win32/xnet.cpp
+++ b/src/remote/os/win32/xnet.cpp
@@ -1068,6 +1068,14 @@ static void cleanup_port(rem_port* port)
  *
  **************************************/
 
+	if (port->port_thread_guard && port->port_events_thread && !Thread::isCurrent(port->port_events_threadId))
+	{
+		//port->port_thread_guard->setWait(port->port_events_thread);
+
+		// Do not release XNET structures while event's thread working
+		Thread::waitForCompletion(port->port_events_thread);
+	}
+
 	if (port->port_xcc)
 	{
 		cleanup_comm(port->port_xcc);
@@ -1996,6 +2004,9 @@ static bool_t xnet_read(XDR* xdrs)
 		const DWORD wait_result =
 			WaitForSingleObject(xcc->xcc_event_recv_channel_filled, XNET_RECV_WAIT_TIMEOUT);
 
+		if (port->port_flags & PORT_disconnect)
+			return FALSE;
+
 		if (wait_result == WAIT_OBJECT_0)
 		{
 			// Client has written some data for us (server) to read