GUACAMOLE-221: Implement function for sending required to client owner.

src/libguac/client.c

@@ -478,6 +478,25 @@ int guac_client_load_plugin(guac_client* client, const char* protocol) {
 
 }
 
+int guac_client_owner_send_required(guac_client* client, const char** required) {
+
+    int retval;
+
+    pthread_rwlock_rdlock(&(client->__users_lock));
+
+    /* Invoke callback with current owner */
+    retval = guac_protocol_send_required(client->__owner->socket, required);
+    
+    /* Flush the socket */
+    guac_socket_flush(client->__owner->socket);
+
+    pthread_rwlock_unlock(&(client->__users_lock));
+
+    /* Return value from sending required */
+    return retval;
+
+}
+
 /**
  * Updates the provided approximate processing lag, taking into account the
  * processing lag of the given user.

src/libguac/guacamole/client.h

@@ -549,6 +549,22 @@ int guac_client_load_plugin(guac_client* client, const char* protocol);
  */
 int guac_client_get_processing_lag(guac_client* client);
 
+/**
+ * Sends a request to the owner of the given guac_client for parameters required
+ * to continue the connection started by the client. The function returns zero
+ * on success or non-zero on failure.
+ * 
+ * @param client
+ *     The client where additional connection parameters are required.
+ * 
+ * @param required
+ *     The NULL-terminated array of required parameters.
+ * 
+ * @return
+ *     Zero on success, non-zero on failure.
+ */
+int guac_client_owner_send_required(guac_client* client, const char** required);
+
 /**
  * Streams the given connection parameter value over an argument value stream
  * ("argv" instruction), exposing the current value of the named connection

src/protocols/rdp/rdp.c

@@ -258,9 +258,8 @@ static BOOL rdp_freerdp_authenticate(freerdp* instance, char** username,
         pthread_mutex_lock(&(rdp_client->rdp_credential_lock));
         
         /* Send require params and flush socket. */
-        guac_socket_require_keep_alive(client->__owner->socket);
-        guac_protocol_send_required(client->__owner->socket, (const char**) params);
-        guac_socket_flush(client->__owner->socket);
+        guac_socket_require_keep_alive(client->socket);
+        guac_client_owner_send_required(client, (const char**) params);
         
         /* Wait for condition. */
         pthread_cond_wait(&(rdp_client->rdp_credential_cond), &(rdp_client->rdp_credential_lock));

src/protocols/ssh/ssh.c

@@ -78,9 +78,8 @@ static void guac_ssh_get_credential(guac_client *client, char* cred_name) {
     pthread_mutex_lock(&(ssh_client->term_channel_lock));
     
     /* Let the owner know what we require and flush the socket. */
-    guac_socket_require_keep_alive(client->__owner->socket);
-    guac_protocol_send_required(client->__owner->socket, (const char* []) {cred_name, NULL});
-    guac_socket_flush(client->__owner->socket);
+    guac_socket_require_keep_alive(client->socket);
+    guac_client_owner_send_required(client, (const char* []) {cred_name, NULL});
     
     /* Wait for the response, and then unlock the thread. */
     pthread_cond_wait(&(ssh_client->ssh_credential_cond), &(ssh_client->term_channel_lock));

src/protocols/vnc/auth.c

@@ -42,10 +42,9 @@ char* guac_vnc_get_password(rfbClient* client) {
         pthread_mutex_lock(&(vnc_client->vnc_credential_lock));
         
         /* Send the request for password and flush the socket. */
-        guac_socket_require_keep_alive(gc->__owner->socket);
-        guac_protocol_send_required(gc->__owner->socket,
+        guac_socket_require_keep_alive(gc->socket);
+        guac_client_owner_send_required(gc,
                 (const char* []) {GUAC_VNC_PARAMETER_NAME_PASSWORD, NULL});
-        guac_socket_flush(gc->__owner->socket);
         
         /* Set the conditional flag. */
         vnc_client->vnc_credential_flags |= GUAC_VNC_COND_FLAG_PASSWORD;
@@ -93,8 +92,8 @@ rfbCredential* guac_vnc_get_credentials(rfbClient* client, int credentialType) {
             pthread_mutex_lock(&(vnc_client->vnc_credential_lock));
             
             /* Send required parameters to client and flush the socket. */
-            guac_protocol_send_required(gc->socket, (const char**) params);
-            guac_socket_flush(gc->socket);
+            guac_socket_require_keep_alive(gc->socket);
+            guac_client_owner_send_required(gc, (const char**) params);
             
             /* Wait for the parameters to be returned. */
             pthread_cond_wait(&(vnc_client->vnc_credential_cond),