GUACAMOLE-25: Abstract DVC management away from FreeRDP for sake of API compatibility.

src/protocols/rdp/Makefile.am

@@ -26,6 +26,7 @@ libguac_client_rdp_la_SOURCES = \
     _generated_keymaps.c        \
     audio_input.c               \
     client.c                    \
+    dvc.c                       \
     input.c                     \
     ptr_string.c                \
     rdp.c                       \
@@ -91,6 +92,7 @@ noinst_HEADERS =                             \
     guac_svc/svc_service.h                   \
     audio_input.h                            \
     client.h                                 \
+    dvc.h                                    \
     input.h                                  \
     ptr_string.h                             \
     rdp.h                                    \

src/protocols/rdp/audio_input.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "audio_input.h"
+#include "dvc.h"
 #include "ptr_string.h"
 #include "rdp.h"
 
@@ -71,17 +72,12 @@ int guac_rdp_audio_end_handler(guac_user* user, guac_stream* stream) {
 
 }
 
-void guac_rdp_audio_load_plugin(rdpContext* context) {
+void guac_rdp_audio_load_plugin(rdpContext* context, guac_rdp_dvc_list* list) {
 
     guac_client* client = ((rdp_freerdp_context*) context)->client;
 
     /* Add "AUDIO_INPUT" channel */
-    ADDIN_ARGV* args = malloc(sizeof(ADDIN_ARGV));
+    guac_rdp_dvc_list_add(list, "guacai", guac_rdp_ptr_to_string(client), NULL);
-    args->argc = 2;
-    args->argv = malloc(sizeof(char**) * 2);
-    args->argv[0] = strdup("guacai");
-    args->argv[1] = guac_rdp_ptr_to_string(client);
-    freerdp_dynamic_channel_collection_add(context->settings, args);
 
 }
 

src/protocols/rdp/audio_input.h

@@ -21,6 +21,7 @@
 #define GUAC_RDP_AUDIO_INPUT_H
 
 #include "config.h"
+#include "dvc.h"
 
 #include <freerdp/freerdp.h>
 #include <guacamole/stream.h>
@@ -213,7 +214,7 @@ guac_user_end_handler guac_rdp_audio_end_handler;
  * @param context
  *     The rdpContext associated with the active RDP session.
  */
-void guac_rdp_audio_load_plugin(rdpContext* context);
+void guac_rdp_audio_load_plugin(rdpContext* context, guac_rdp_dvc_list* list);
 
 #endif
 

src/protocols/rdp/dvc.c

@@ -0,0 +1,154 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "dvc.h"
+#include "guac_list.h"
+#include "rdp.h"
+
+#include <freerdp/channels/channels.h>
+#include <freerdp/freerdp.h>
+#include <guacamole/client.h>
+
+#include <assert.h>
+#include <stdarg.h>
+
+guac_rdp_dvc_list* guac_rdp_dvc_list_alloc() {
+
+    guac_rdp_dvc_list* list = malloc(sizeof(guac_rdp_dvc_list));
+
+    /* Initialize with empty backing list */
+    list->channels = guac_common_list_alloc();
+    list->channel_count = 0;
+
+    return list;
+
+}
+
+void guac_rdp_dvc_list_add(guac_rdp_dvc_list* list, const char* name, ...) {
+
+    va_list args;
+
+    guac_rdp_dvc* dvc = malloc(sizeof(guac_rdp_dvc));
+
+    va_start(args, name);
+
+    /* Count number of arguments (excluding terminating NULL) */
+    dvc->argc = 1;
+    while (va_arg(args, char*) != NULL)
+        dvc->argc++;
+
+    /* Reset va_list */
+    va_end(args);
+    va_start(args, name);
+
+    /* Copy argument values into DVC entry */
+    dvc->argv = malloc(sizeof(char*) * dvc->argc);
+    dvc->argv[0] = strdup(name);
+    int i;
+    for (i = 1; i < dvc->argc; i++)
+        dvc->argv[i] = strdup(va_arg(args, char*));
+
+    va_end(args);
+
+    /* Add entry to DVC list */
+    guac_common_list_add(list->channels, dvc);
+
+    /* Update channel count */
+    list->channel_count++;
+
+}
+
+void guac_rdp_dvc_list_free(guac_rdp_dvc_list* list) {
+
+    /* For each channel */
+    guac_common_list_element* current = list->channels->head;
+    while (current != NULL) {
+
+        /* Free arguments declaration for current channel */
+        guac_rdp_dvc* dvc = (guac_rdp_dvc*) current->data;
+
+        /* Free the underlying arguments list if not delegated to FreeRDP */
+        if (dvc->argv != NULL) {
+
+            /* Free each argument value */
+            for (int i = 0; i < dvc->argc; i++)
+                free(dvc->argv[i]);
+
+            free(dvc->argv);
+        }
+
+        free(dvc);
+
+        current = current->next;
+
+    }
+
+    /* Free underlying list */
+    guac_common_list_free(list->channels);
+
+    /* Free the DVC list itself */
+    free(list);
+
+}
+
+int guac_rdp_load_drdynvc(rdpContext* context, guac_rdp_dvc_list* list) {
+
+    guac_client* client = ((rdp_freerdp_context*) context)->client;
+    rdpChannels* channels = context->channels;
+
+    /* Skip if no channels will be loaded */
+    if (list->channel_count == 0)
+        return 0;
+
+    /* For each channel */
+    guac_common_list_element* current = list->channels->head;
+    while (current != NULL) {
+
+        /* Get channel arguments */
+        guac_rdp_dvc* dvc = (guac_rdp_dvc*) current->data;
+        current = current->next;
+
+        /* guac_rdp_dvc_list_add() guarantees at one argument */
+        assert(dvc->argc >= 1);
+
+        /* guac_rdp_load_drdynvc() MUST only be invoked once */
+        assert(dvc->argv != NULL);
+
+        /* Log registration of plugin for current channel */
+        guac_client_log(client, GUAC_LOG_DEBUG,
+                "Registering DVC plugin \"%s\"", dvc->argv[0]);
+
+        /* Register plugin with FreeRDP */
+        ADDIN_ARGV* args = malloc(sizeof(ADDIN_ARGV));
+        args->argc = dvc->argc;
+        args->argv = dvc->argv;
+        freerdp_dynamic_channel_collection_add(context->settings, args);
+
+        /* Rely on FreeRDP to free argv storage */
+        dvc->argv = NULL;
+
+    }
+
+    /* Load virtual channel management plugin */
+    return freerdp_channels_load_plugin(channels, context->settings,
+                "drdynvc", context->settings);
+
+}
+

src/protocols/rdp/dvc.h

@@ -0,0 +1,138 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_RDP_DVC_H
+#define GUAC_RDP_DVC_H
+
+#include "config.h"
+#include "guac_list.h"
+
+#include <freerdp/freerdp.h>
+
+/**
+ * The set of all arguments that should be passed to a given dynamic virtual
+ * channel plugin, including the name of that plugin.
+ */
+typedef struct guac_rdp_dvc {
+
+    /**
+     * The number of arguments in the argv array. This MUST be at least 1.
+     */
+    int argc;
+
+    /**
+     * The argument values being passed to the dynamic virtual channel plugin.
+     * The first entry in this array is always the name of the plugin. If
+     * guac_rdp_load_drdynvc() has been invoked, and freeing the argument
+     * values is being delegated to FreeRDP, this will be NULL.
+     */
+    char** argv;
+
+} guac_rdp_dvc;
+
+/**
+ * A list of dynamic virtual channels which should be provided to the DRDYNVC
+ * plugin once loaded via guac_rdp_load_drdynvc(). This interface exists purely
+ * to bridge incompatibilities between differing versions of FreeRDP and its
+ * DRDYNVC plugin. Any allocated guac_rdp_dvc_list is unlikely to be needed
+ * after the DRDYNVC plugin has been loaded.
+ */
+typedef struct guac_rdp_dvc_list {
+
+    /**
+     * Array of all dynamic virtual channels which should be registered with
+     * the DRDYNVC plugin once loaded. Each list element will point to a
+     * guac_rdp_dvc structure which must eventually be freed.
+     */
+    guac_common_list* channels;
+
+    /**
+     * The number of channels within the list.
+     */
+    int channel_count;
+
+} guac_rdp_dvc_list;
+
+/**
+ * Allocates a new, empty list of dynamic virtual channels. New channels may
+ * be added via guac_rdp_dvc_list_add(). The loading of those channels'
+ * associated plugins will be deferred until guac_rdp_load_drdynvc() is
+ * invoked.
+ *
+ * @return
+ *     A newly-allocated, empty list of dynamic virtual channels.
+ */
+guac_rdp_dvc_list* guac_rdp_dvc_list_alloc();
+
+/**
+ * Adds the given dynamic virtual channel plugin name and associated arguments
+ * to the list. The provied arguments list is NOT optional and MUST be
+ * NULL-terminated, even if there are no arguments for the named dynamic
+ * virtual channel plugin. Though FreeRDP requires that the arguments for a
+ * dynamic virtual channel plugin contain the name of the plugin itself as the
+ * first argument, the name must be excluded from the arguments provided here.
+ * This function will automatically take care of adding the plugin name to
+ * the arguments.
+ *
+ * @param list
+ *     The guac_rdp_dvc_list to which the given plugin name and arguments
+ *     should be added, for later bulk registration via
+ *     guac_rdp_load_drdynvc().
+ *
+ * @param name
+ *     The name of the dynamic virtual channel plugin that should be given
+ *     the provided arguments when guac_rdp_load_drdynvc() is invoked.
+ *
+ * @param ...
+ *     The string (char*) arguments which should be passed to the dynamic
+ *     virtual channel plugin when it is loaded via guac_rdp_load_drdynvc(),
+ *     excluding the plugin name itself.
+ */
+void guac_rdp_dvc_list_add(guac_rdp_dvc_list* list, const char* name, ...);
+
+/**
+ * Frees the given list of dynamic virtual channels. Note that, while each
+ * individual entry within this list will be freed, it is partially up to
+ * FreeRDP to free the storage associated with the arguments passed to the
+ * virtual channels.
+ *
+ * @param list
+ *     The list to free.
+ */
+void guac_rdp_dvc_list_free(guac_rdp_dvc_list* list);
+
+/**
+ * Loads FreeRDP's DRDYNVC plugin and registers the dynamic virtual channel
+ * plugins described by the given guac_rdp_dvc_list. This function MUST be
+ * invoked no more than once per RDP connection. Invoking this function
+ * multiple times, even if the guac_rdp_dvc_list is different each time, will
+ * result in undefined behavior.
+ *
+ * @param context
+ *     The rdpContext associated with the RDP connection for which the DRDYNVC
+ *     plugin should be loaded.
+ *
+ * @param list
+ *     A guac_rdp_dvc_list describing the dynamic virtual channel plugins that
+ *     should be registered with the DRDYNVC plugin, along with any arguments.
+ */
+int guac_rdp_load_drdynvc(rdpContext* context, guac_rdp_dvc_list* list);
+
+#endif
+

src/protocols/rdp/rdp.c

@@ -21,6 +21,7 @@
 
 #include "audio_input.h"
 #include "client.h"
+#include "dvc.h"
 #include "guac_cursor.h"
 #include "guac_display.h"
 #include "guac_recording.h"
@@ -212,6 +213,7 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
     rdpPrimaryUpdate* primary;
     CLRCONV* clrconv;
 
+    guac_rdp_dvc_list* dvc_list = guac_rdp_dvc_list_alloc();
 
 #ifdef HAVE_FREERDP_REGISTER_ADDIN_PROVIDER
     /* Init FreeRDP add-in provider */
@@ -224,35 +226,18 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
             (pChannelConnectedEventHandler) guac_rdp_channel_connected);
 #endif
 
-    /* Load DRDYNVC plugin if required */
-    if (settings->resize_method == GUAC_RESIZE_DISPLAY_UPDATE
-            || settings->enable_audio_input) {
-
-        /* Load virtual channel management plugin */
-        if (freerdp_channels_load_plugin(channels, instance->settings,
-                    "drdynvc", instance->settings))
-            guac_client_log(client, GUAC_LOG_WARNING,
-                    "Failed to load drdynvc plugin. Display update and audio "
-                    "input support will be disabled.");
-
-        /* Init display update plugin if "drdynvc" was loaded successfully */
-        else {
 #ifdef HAVE_FREERDP_DISPLAY_UPDATE_SUPPORT
     /* Load "disp" plugin for display update */
     if (settings->resize_method == GUAC_RESIZE_DISPLAY_UPDATE)
-                guac_rdp_disp_load_plugin(instance->context);
+        guac_rdp_disp_load_plugin(instance->context, dvc_list);
 #endif
 
     /* Load "AUDIO_INPUT" plugin for audio input*/
     if (settings->enable_audio_input) {
         rdp_client->audio_input = guac_rdp_audio_buffer_alloc();
-                guac_rdp_audio_load_plugin(instance->context);
+        guac_rdp_audio_load_plugin(instance->context, dvc_list);
     }
 
-        }
-
-    } /* end if drdynvc required */
-
     /* Load clipboard plugin */
     if (freerdp_channels_load_plugin(channels, instance->settings,
                 "cliprdr", NULL))
@@ -338,6 +323,15 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
 
     }
 
+    /* Load DRDYNVC plugin if required */
+    if (guac_rdp_load_drdynvc(instance->context, dvc_list))
+        guac_client_log(client, GUAC_LOG_WARNING,
+                "Failed to load drdynvc plugin. Display update and audio "
+                "input support will be disabled.");
+
+    /* Dynamic virtual channel list is no longer needed */
+    guac_rdp_dvc_list_free(dvc_list);
+
     /* Init color conversion structure */
     clrconv = calloc(1, sizeof(CLRCONV));
     clrconv->alpha = 1;

src/protocols/rdp/rdp_disp.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "client.h"
+#include "dvc.h"
 #include "rdp.h"
 #include "rdp_disp.h"
 #include "rdp_settings.h"
@@ -54,20 +55,14 @@ void guac_rdp_disp_free(guac_rdp_disp* disp) {
     free(disp);
 }
 
-void guac_rdp_disp_load_plugin(rdpContext* context) {
+void guac_rdp_disp_load_plugin(rdpContext* context, guac_rdp_dvc_list* list) {
 
-#ifdef HAVE_FREERDP_DISPLAY_UPDATE_SUPPORT
 #ifdef HAVE_RDPSETTINGS_SUPPORTDISPLAYCONTROL
     context->settings->SupportDisplayControl = TRUE;
 #endif
 
     /* Add "disp" channel */
-    ADDIN_ARGV* args = malloc(sizeof(ADDIN_ARGV));
+    guac_rdp_dvc_list_add(list, "disp", NULL);
-    args->argc = 1;
-    args->argv = malloc(sizeof(char**) * 1);
-    args->argv[0] = strdup("disp");
-    freerdp_dynamic_channel_collection_add(context->settings, args);
-#endif
 
 }
 

src/protocols/rdp/rdp_disp.h

@@ -20,6 +20,7 @@
 #ifndef GUAC_RDP_DISP_H
 #define GUAC_RDP_DISP_H
 
+#include "dvc.h"
 #include "rdp_settings.h"
 
 #include <freerdp/freerdp.h>
@@ -102,7 +103,7 @@ void guac_rdp_disp_free(guac_rdp_disp* disp);
  *
  * @param context The rdpContext associated with the active RDP session.
  */
-void guac_rdp_disp_load_plugin(rdpContext* context);
+void guac_rdp_disp_load_plugin(rdpContext* context, guac_rdp_dvc_list* list);
 
 #ifdef HAVE_FREERDP_DISPLAY_UPDATE_SUPPORT
 /**