GUACAMOLE-51: Track and synchronize remote lock key state.

src/protocols/rdp/keyboard.c

@@ -31,6 +31,46 @@
 #include <pthread.h>
 #include <stdlib.h>
 
+/**
+ * Translates the given keysym into the corresponding lock flag, as would be
+ * required by the RDP synchronize event. If the given keysym does not
+ * represent a lock key, zero is returned.
+ *
+ * @param keysym
+ *     The keysym to translate into a RDP lock flag.
+ *
+ * @return
+ *     The RDP lock flag which corresponds to the given keysym, or zero if the
+ *     given keysym does not represent a lock key.
+ */
+static int guac_rdp_keyboard_lock_flag(int keysym) {
+
+    /* Translate keysym into corresponding lock flag */
+    switch (keysym) {
+
+        /* Scroll lock */
+        case 0xFF14:
+            return KBD_SYNC_SCROLL_LOCK;
+
+        /* Kana lock */
+        case 0xFF2D:
+            return KBD_SYNC_KANA_LOCK;
+
+        /* Num lock */
+        case 0xFF7F:
+            return KBD_SYNC_NUM_LOCK;
+
+        /* Caps lock */
+        case 0xFFE5:
+            return KBD_SYNC_CAPS_LOCK;
+
+    }
+
+    /* Not a lock key */
+    return 0;
+
+}
+
 /**
  * Immediately sends an RDP key event having the given scancode and flags.
  *
@@ -113,6 +153,39 @@ static void guac_rdp_send_unicode_event(guac_rdp_client* rdp_client,
 
 }
 
+/**
+ * Immediately sends an RDP synchonize event having the given flags. An RDP
+ * synchronize event sets the state of remote lock keys absolutely, where a
+ * lock key will be active only if its corresponding flag is set in the event.
+ *
+ * @param rdp_client
+ *     The RDP client instance associated with the RDP session along which the
+ *     synchronize event should be sent.
+ *
+ * @param flags
+ *     Bitwise OR of the flags representing the lock keys which should be set,
+ *     if any, as dictated by the RDP protocol. If no flags are set, then no
+ *     lock keys will be active.
+ */
+static void guac_rdp_send_synchronize_event(guac_rdp_client* rdp_client,
+        int flags) {
+
+    pthread_mutex_lock(&(rdp_client->rdp_lock));
+
+    /* Skip if not yet connected */
+    freerdp* rdp_inst = rdp_client->rdp_inst;
+    if (rdp_inst == NULL) {
+        pthread_mutex_unlock(&(rdp_client->rdp_lock));
+        return;
+    }
+
+    /* Synchronize lock key states */
+    rdp_inst->input->SynchronizeEvent(rdp_inst->input, flags);
+
+    pthread_mutex_unlock(&(rdp_client->rdp_lock));
+
+}
+
 /**
  * Loads all keysym/scancode mappings declared within the given keymap and its
  * parent keymap, if any. These mappings are stored within the given
@@ -187,6 +260,11 @@ int guac_rdp_keyboard_send_event(guac_rdp_keyboard* keyboard,
         /* If defined, send event */
         if (keysym_desc->scancode != 0) {
 
+            /* Update remote lock state as necessary */
+            guac_rdp_keyboard_update_locks(keyboard,
+                    keysym_desc->set_locks,
+                    keysym_desc->clear_locks);
+
             /* If defined, send any prerequesite keys that must be set */
             if (keysym_desc->set_keysyms != NULL)
                 guac_rdp_keyboard_send_events(keyboard,
@@ -270,9 +348,42 @@ void guac_rdp_keyboard_send_events(guac_rdp_keyboard* keyboard,
 
 }
 
+void guac_rdp_keyboard_update_locks(guac_rdp_keyboard* keyboard,
+        int set_flags, int clear_flags) {
+
+    guac_client* client = keyboard->client;
+    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+
+    /* Calculate updated lock flags */
+    int lock_flags = (keyboard->lock_flags | set_flags) & ~clear_flags;
+
+    /* Synchronize remote side only if lock flags have changed */
+    if (lock_flags != keyboard->lock_flags) {
+        guac_rdp_send_synchronize_event(rdp_client, lock_flags);
+        keyboard->lock_flags = lock_flags;
+    }
+
+}
+
 int guac_rdp_keyboard_update_keysym(guac_rdp_keyboard* keyboard,
         int keysym, int pressed) {
 
+    /* Synchronize lock keys states, if this has not yet been done */
+    if (!keyboard->synchronized) {
+
+        guac_client* client = keyboard->client;
+        guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+
+        /* Synchronize remote lock key states with local state */
+        guac_rdp_send_synchronize_event(rdp_client, keyboard->lock_flags);
+        keyboard->synchronized = 1;
+
+    }
+
+    /* Toggle lock flag, if any */
+    if (pressed)
+        keyboard->lock_flags ^= guac_rdp_keyboard_lock_flag(keysym);
+
     /* Update keysym state */
     if (GUAC_RDP_KEYSYM_STORABLE(keysym))
         GUAC_RDP_KEYSYM_LOOKUP(keyboard->keysym_state, keysym) = pressed;

src/protocols/rdp/keyboard.h

@@ -35,6 +35,19 @@ typedef struct guac_rdp_keyboard {
      */
     guac_client* client;
 
+    /**
+     * The local state of all known 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.
+     */
+    int lock_flags;
+
+    /**
+     * Whether the states of remote lock keys (Caps lock, Num lock, etc.) have
+     * been synchronized with local lock key states.
+     */
+    int synchronized;
+
     /**
      * The keymap to use when translating keysyms into scancodes or sequences
      * of scancodes for RDP.
@@ -127,6 +140,26 @@ int guac_rdp_keyboard_send_event(guac_rdp_keyboard* keyboard,
 void guac_rdp_keyboard_send_events(guac_rdp_keyboard* keyboard,
         const int* keysym_string, int from, int to);
 
+/**
+ * Updates the local state of the lock keys (such as Caps lock or Num lock),
+ * synchronizing the remote state of those keys if it is expected to differ.
+ *
+ * @param keyboard
+ *     The guac_rdp_keyboard associated with the current RDP session.
+ *
+ * @param set_flags
+ *     The lock key flags which should be set. Legal flags are
+ *     KBD_SYNC_SCROLL_LOCK, KBD_SYNC_NUM_LOCK, KBD_SYNC_CAPS_LOCK, and
+ *     KBD_SYNC_KANA_LOCK.
+ *
+ * @param clear_flags
+ *     The lock key flags which should be cleared. Legal flags are
+ *     KBD_SYNC_SCROLL_LOCK, KBD_SYNC_NUM_LOCK, KBD_SYNC_CAPS_LOCK, and
+ *     KBD_SYNC_KANA_LOCK.
+ */
+void guac_rdp_keyboard_update_locks(guac_rdp_keyboard* keyboard,
+        int set_flags, int clear_flags);
+
 /**
  * Updates the local state of the given keysym, sending the key events required
  * to replicate that state remotely (on the RDP server). The key events sent

src/protocols/rdp/rdp_keymap.h

@@ -62,6 +62,22 @@ typedef struct guac_rdp_keysym_desc {
      */
     const int* clear_keysyms;
 
+    /**
+     * Bitwise OR of the flags of all lock keys (ie: Caps lock, Num lock, etc.)
+     * which must be active for this keysym to be properly typed. Legal flags
+     * are KBD_SYNC_SCROLL_LOCK, KBD_SYNC_NUM_LOCK, KBD_SYNC_CAPS_LOCK, and
+     * KBD_SYNC_KANA_LOCK.
+     */
+    int set_locks;
+
+    /**
+     * Bitwise OR of the flags of all lock keys (ie: Caps lock, Num lock, etc.)
+     * which must be inactive for this keysym to be properly typed. Legal flags
+     * are KBD_SYNC_SCROLL_LOCK, KBD_SYNC_NUM_LOCK, KBD_SYNC_CAPS_LOCK, and
+     * KBD_SYNC_KANA_LOCK.
+     */
+    int clear_locks;
+
 } guac_rdp_keysym_desc;
 
 /**