GUACAMOLE-518: Keep locally-tracked keyboard lock status in sync with remote changes to keyboard locks.

src/protocols/rdp/keyboard.c

@@ -709,3 +709,24 @@ void guac_rdp_keyboard_reset(guac_rdp_keyboard* keyboard) {
 
 }
 
+BOOL guac_rdp_keyboard_set_indicators(rdpContext* context, UINT16 flags) {
+
+    guac_client* client = ((rdp_freerdp_context*) context)->client;
+    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+
+    pthread_rwlock_rdlock(&(rdp_client->lock));
+
+    /* Skip if keyboard not yet ready */
+    guac_rdp_keyboard* keyboard = rdp_client->keyboard;
+    if (keyboard == NULL)
+        goto complete;
+
+    /* Update with received locks */
+    guac_client_log(client, GUAC_LOG_DEBUG, "Received updated keyboard lock flags from RDP server: 0x%X", flags);
+    keyboard->lock_flags = flags;
+
+complete:
+    pthread_rwlock_unlock(&(rdp_client->lock));
+    return TRUE;
+
+}

src/protocols/rdp/keyboard.h

@@ -22,6 +22,7 @@
 
 #include "keymap.h"
 
+#include <freerdp/freerdp.h>
 #include <guacamole/client.h>
 
 /**
@@ -279,5 +280,22 @@ int guac_rdp_keyboard_update_keysym(guac_rdp_keyboard* keyboard,
  */
 void guac_rdp_keyboard_reset(guac_rdp_keyboard* keyboard);
 
+/**
+ * Callback which is invoked by FreeRDP when the RDP server reports changes to
+ * keyboard lock status using a Server Set Keyboard Indicators PDU.
+ *
+ * @param context
+ *     The rdpContext associated with the current RDP session.
+ *
+ * @param flags
+ *     The remote state of all lock keys, as a bitwise OR of all RDP lock key
+ *     flags. Legal flags are KBD_SYNC_SCROLL_LOCK, KBD_SYNC_NUM_LOCK,
+ *     KBD_SYNC_CAPS_LOCK, and KBD_SYNC_KANA_LOCK.
+ *
+ * @return
+ *     TRUE if successful, FALSE otherwise.
+ */
+BOOL guac_rdp_keyboard_set_indicators(rdpContext* context, UINT16 flags);
+
 #endif
 

src/protocols/rdp/rdp.c

@@ -173,6 +173,9 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
     /* Beep on receipt of Play Sound PDU */
     instance->update->PlaySound = guac_rdp_beep_play_sound;
 
+    /* Automatically synchronize keyboard locks when changed server-side */
+    instance->update->SetKeyboardIndicators = guac_rdp_keyboard_set_indicators;
+
     /* Set up GDI */
     instance->update->DesktopResize = guac_rdp_gdi_desktop_resize;
     instance->update->EndPaint = guac_rdp_gdi_end_paint;