GUACAMOLE-1846: Check for NULLs before attempting to sync state in jo…

…in pending handlers.

(cherry picked from commit cf6d80b)

src/protocols/kubernetes/client.c

@@ -95,10 +95,12 @@ static int guac_kubernetes_join_pending_handler(guac_client* client) {
         (guac_kubernetes_client*) client->data;
 
     /* Synchronize the terminal state to all pending users */
-    guac_socket* broadcast_socket = client->pending_socket;
-    guac_terminal_sync_users(kubernetes_client->term, client, broadcast_socket);
-    guac_kubernetes_send_current_argv_batch(client, broadcast_socket);
-    guac_socket_flush(broadcast_socket);
+    if (kubernetes_client->term != NULL) {
+        guac_socket* broadcast_socket = client->pending_socket;
+        guac_terminal_sync_users(kubernetes_client->term, client, broadcast_socket);
+        guac_kubernetes_send_current_argv_batch(client, broadcast_socket);
+        guac_socket_flush(broadcast_socket);
+    }
 
     return 0;
 

src/protocols/rdp/client.c

@@ -125,9 +125,10 @@ static int guac_rdp_join_pending_handler(guac_client* client) {
     guac_rdp_pipe_svc_send_pipes(client, broadcast_socket);
 
     /* Synchronize with current display */
-    guac_common_display_dup(rdp_client->display, client, broadcast_socket);
-
-    guac_socket_flush(broadcast_socket);
+    if (rdp_client->display != NULL) {
+        guac_common_display_dup(rdp_client->display, client, broadcast_socket);
+        guac_socket_flush(broadcast_socket);
+    }
 
     return 0;
 

src/protocols/ssh/client.c

@@ -52,10 +52,12 @@ static int guac_ssh_join_pending_handler(guac_client* client) {
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
 
     /* Synchronize the terminal state to all pending users */
-    guac_socket* broadcast_socket = client->pending_socket;
-    guac_terminal_sync_users(ssh_client->term, client, broadcast_socket);
-    guac_ssh_send_current_argv_batch(client, broadcast_socket);
-    guac_socket_flush(broadcast_socket);
+    if (ssh_client->term != NULL) {
+        guac_socket* broadcast_socket = client->pending_socket;
+        guac_terminal_sync_users(ssh_client->term, client, broadcast_socket);
+        guac_ssh_send_current_argv_batch(client, broadcast_socket);
+        guac_socket_flush(broadcast_socket);
+    }
 
     return 0;
 

src/protocols/telnet/client.c

@@ -51,10 +51,12 @@ static int guac_telnet_join_pending_handler(guac_client* client) {
     guac_telnet_client* telnet_client = (guac_telnet_client*) client->data;
 
     /* Synchronize the terminal state to all pending users */
-    guac_socket* broadcast_socket = client->pending_socket;
-    guac_terminal_sync_users(telnet_client->term, client, broadcast_socket);
-    guac_telnet_send_current_argv_batch(client, broadcast_socket);
-    guac_socket_flush(broadcast_socket);
+    if (telnet_client->term != NULL) {
+        guac_socket* broadcast_socket = client->pending_socket;
+        guac_terminal_sync_users(telnet_client->term, client, broadcast_socket);
+        guac_telnet_send_current_argv_batch(client, broadcast_socket);
+        guac_socket_flush(broadcast_socket);
+    }
 
     return 0;
 

src/protocols/vnc/client.c

@@ -87,8 +87,10 @@ static int guac_vnc_join_pending_handler(guac_client* client) {
 #endif
 
     /* Synchronize with current display */
-    guac_common_display_dup(vnc_client->display, client, broadcast_socket);
-    guac_socket_flush(broadcast_socket);
+    if (vnc_client->display != NULL) {
+        guac_common_display_dup(vnc_client->display, client, broadcast_socket);
+        guac_socket_flush(broadcast_socket);
+    }
 
     return 0;