Merge commit 'mysql-8.0' into mysql-trunk

Change-Id: I1da6faa2718a36b427519b25392be79d7acf88e6

Author: zmur

storage/ndb/include/util/NdbSocket.h

@@ -307,20 +307,23 @@ uint NdbSocket::add_writable(ndb_socket_poller * poller) const {
 
 inline
 int NdbSocket::poll_readable(int timeout) const {
+  if (!is_valid()) return -1;
   ndb_socket_poller poller;
   poller.add_readable(s, ssl);
   return poller.poll(timeout);
 }
 
 inline
 int NdbSocket::poll_writable(int timeout) const {
+  if (!is_valid()) return -1;
   ndb_socket_poller poller;
   poller.add_writable(s);
   return poller.poll(timeout);
 }
 
 inline
 bool NdbSocket::check_hup() const {
+  if (!is_valid()) return true;
   ndb_socket_poller poller;
   poller.add_readable(s);
   if(poller.poll_unsafe(0) > 0 && poller.has_hup(0))

storage/ndb/src/common/util/socket_io.cpp

@@ -57,6 +57,9 @@ poll_socket(ndb_socket_t socket, bool read, bool write,
 int
 read_socket(ndb_socket_t socket, int timeout_millis,
 	    char * buf, int buflen){
+  if (!ndb_socket_valid(socket))
+    return -1;
+
   if(buflen < 1)
     return 0;
 
@@ -72,6 +75,9 @@ read_socket(ndb_socket_t socket, int timeout_millis,
 int
 readln_socket(ndb_socket_t socket, int timeout_millis, int *time,
 	      char * buf, int buflen, NdbMutex *mutex){
+  if (!ndb_socket_valid(socket))
+    return -1;
+
   if(buflen <= 1)
     return 0;