From e58fbba00a9439fc918d0ebd44f943818cb664f7 Mon Sep 17 00:00:00 2001
From: "Evgeny Grin (Karlson2k)" <k2k@narod.ru>
Date: Thu, 8 Oct 2020 15:20:50 +0300
Subject: [PATCH] internal_add_connection: refuse blocking sockets in epoll
 mode

---
 src/microhttpd/daemon.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index 42c21b6c..c5e51d37 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -2404,9 +2404,8 @@ internal_add_connection (struct MHD_Daemon *daemon,
   }
 #endif
 
-  if ( (! MHD_SCKT_FD_FITS_FDSET_ (client_socket,
-                                   NULL)) &&
-       (0 == (daemon->options & (MHD_USE_POLL | MHD_USE_EPOLL))) )
+  if ( (0 == (daemon->options & (MHD_USE_POLL | MHD_USE_EPOLL))) &&
+       (! MHD_SCKT_FD_FITS_FDSET_ (client_socket, NULL)) )
   {
 #ifdef HAVE_MESSAGES
     MHD_DLOG (daemon,
@@ -2415,6 +2414,20 @@ internal_add_connection (struct MHD_Daemon *daemon,
               (int) FD_SETSIZE);
 #endif
     MHD_socket_close_chk_ (client_socket);
+#if ENFILE
+    errno = ENFILE;
+#endif
+    return MHD_NO;
+  }
+
+  if ( (0 == (daemon->options & MHD_USE_EPOLL)) &&
+       (! non_blck) )
+  {
+#ifdef HAVE_MESSAGES
+    MHD_DLOG (daemon,
+              _ ("Epoll mode supports only non-blocking sockets\n"));
+#endif
+    MHD_socket_close_chk_ (client_socket);
 #if EINVAL
     errno = EINVAL;
 #endif