If fork()ing, parent process must close child's socket fd. Child close() is not sufficient as both parent and child have a reference to the same socket fd, and fd will never be free'd if close() is not called from both processes.

guacd/src/daemon.c

@@ -302,6 +302,11 @@ int main(int argc, char* argv[]) {
             return 0;
         }
 
+        /* If parent, close reference to child's descriptor */
+        else if (CLOSE_SOCKET(connected_socket_fd) < 0) {
+            guac_log_error("Error closing daemon reference to child descriptor: %s", lasterror());
+        }
+
 #else
 
         if (guac_thread_create(&thread, start_client_thread, (void*) data))