From c5b7137f2b1170cddf79bd79d39224aee4aba7d5 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Mon, 18 May 2020 19:40:49 +0200
Subject: [PATCH] Flush data on close

There might be some final handshake data that is still stuck in the
buffers, so make a best effort attempt at getting it to the client.
---
 common/rfb/VNCSConnectionST.cxx | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index 31bd16e..9e7f3de 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -155,6 +155,17 @@ void VNCSConnectionST::close(const char* reason)
       server->lastDisconnectTime = time(0);
   }
 
+  try {
+    if (sock->outStream().bufferUsage() > 0) {
+      sock->cork(false);
+      sock->outStream().flush();
+      if (sock->outStream().bufferUsage() > 0)
+        vlog.error("Failed to flush remaining socket data on close");
+    }
+  } catch (rdr::Exception& e) {
+    vlog.error("Failed to flush remaining socket data on close: %s", e.str());
+  }
+
   // Just shutdown the socket and mark our state as closing.  Eventually the
   // calling code will call VNCServerST's removeSocket() method causing us to
   // be deleted.