[gnome-remote-desktop] Explicitly enable/disable backends via a setting

[Jonas Ådahl <jadahl src gnome org>]

commit 4f80037a1e17e3205d1a07cf8060a46f92a12f48
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Jan 24 09:36:25 2022 +0100

    Explicitly enable/disable backends via a setting
    
    One might want to run the RDP server without enabling VNC, or vice
    versa. Make this more explicit and less dependent on things being
    configured by adding a setting under each backends settings schema.
    
    This also removes session tracking from GrdContext, and responsibility
    of management of sessions are fully moved to the corresponding server
    implementations.

 .gitlab-ci.yml                                     |   1 +
 .gitlab-ci/run-tests.sh                            |   1 +
 src/grd-context.c                                  |  24 -----
 src/grd-context.h                                  |   5 -
 src/grd-daemon.c                                   | 106 +++++++++++++++------
 src/grd-rdp-server.c                               |   1 -
 src/grd-settings.c                                 |  62 +++++++++++-
 src/grd-settings.h                                 |   4 +
 src/grd-vnc-server.c                               |   1 -
 ...org.gnome.desktop.remote-desktop.gschema.xml.in |  14 +++
 10 files changed, 155 insertions(+), 64 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5ae7012e..f2616576 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -105,6 +105,7 @@ test-gnome-remote-desktop:
   variables:
     XDG_RUNTIME_DIR: "$CI_PROJECT_DIR/runtime-dir"
     GSETTINGS_SCHEMA_DIR: "$CI_PROJECT_DIR/build/src"
+    GSETTINGS_BACKEND: "keyfile"
   script:
     - mkdir -m 700 $XDG_RUNTIME_DIR
     - glib-compile-schemas $GSETTINGS_SCHEMA_DIR
diff --git a/.gitlab-ci/run-tests.sh b/.gitlab-ci/run-tests.sh
index 88867a74..5f7aea4a 100755
--- a/.gitlab-ci/run-tests.sh
+++ b/.gitlab-ci/run-tests.sh
@@ -7,4 +7,5 @@ sleep 1
 wireplumber &
 sleep 1
 
+gsettings set org.gnome.desktop.remote-desktop.vnc enable true
 meson test -C build --no-rebuild --verbose --no-stdsplit -t 10
diff --git a/src/grd-context.c b/src/grd-context.c
index 0d9bed1d..fd62ec97 100644
--- a/src/grd-context.c
+++ b/src/grd-context.c
@@ -46,8 +46,6 @@ struct _GrdContext
 
   GrdSettings *settings;
 
-  GList *sessions;
-
   GrdDebugFlags debug_flags;
 };
 
@@ -87,28 +85,6 @@ grd_context_get_main_context (GrdContext *context)
   return context->main_context;
 }
 
-static void
-on_session_stopped (GrdSession *session,
-                    GrdContext *context)
-{
-  context->sessions = g_list_remove (context->sessions, session);
-}
-
-void
-grd_context_add_session (GrdContext *context,
-                         GrdSession *session)
-{
-  context->sessions = g_list_append (context->sessions, session);
-  g_signal_connect (session, "stopped",
-                    G_CALLBACK (on_session_stopped), context);
-}
-
-GList *
-grd_context_get_sessions (GrdContext *context)
-{
-  return context->sessions;
-}
-
 GrdSettings *
 grd_context_get_settings (GrdContext *context)
 {
diff --git a/src/grd-context.h b/src/grd-context.h
index a7b9cb87..d94d8054 100644
--- a/src/grd-context.h
+++ b/src/grd-context.h
@@ -53,11 +53,6 @@ GrdPipeWireStreamMonitor *grd_context_get_pipewire_stream_monitor (GrdContext *c
 
 GMainContext *grd_context_get_main_context (GrdContext *context);
 
-void grd_context_add_session (GrdContext *context,
-                              GrdSession *session);
-
-GList * grd_context_get_sessions (GrdContext *context);
-
 GrdSettings * grd_context_get_settings (GrdContext *context);
 
 GrdEglThread * grd_context_get_egl_thread (GrdContext *context);
diff --git a/src/grd-daemon.c b/src/grd-daemon.c
index 64fe5ed2..54a27888 100644
--- a/src/grd-daemon.c
+++ b/src/grd-daemon.c
@@ -68,29 +68,27 @@ is_daemon_ready (GrdDaemon *daemon)
 }
 
 #ifdef HAVE_RDP
-static gboolean
-init_rdp_server (GrdDaemon *daemon)
+static void
+start_rdp_server (GrdDaemon *daemon)
 {
   GrdSettings *settings = grd_context_get_settings (daemon->context);
   g_autoptr (GError) error = NULL;
-  gboolean result = FALSE;
 
-  daemon->rdp_server = NULL;
+  g_assert (!daemon->rdp_server);
+
   if (!g_access (grd_settings_get_rdp_server_cert (settings), F_OK) &&
       !g_access (grd_settings_get_rdp_server_key (settings), F_OK))
     {
       daemon->rdp_server = grd_rdp_server_new (daemon->context);
-      if (!(result = grd_rdp_server_start (daemon->rdp_server, &error)))
-        g_warning ("Failed to initialize RDP server: %s\n", error->message);
+      if (!grd_rdp_server_start (daemon->rdp_server, &error))
+        g_warning ("Failed to start RDP server: %s\n", error->message);
       else
-        g_message ("Initialized RDP server");
+        g_message ("RDP server started");
     }
   else
     {
-      g_message ("Didn't initialize RDP server: not configured");
+      g_warning ("RDP TLS certificate and key not configured properly");
     }
-
-  return result;
 }
 
 static void
@@ -99,26 +97,25 @@ stop_rdp_server (GrdDaemon *daemon)
   if (!daemon->rdp_server)
     return;
 
-  g_message ("Stopping RDP server");
   grd_rdp_server_stop (daemon->rdp_server);
   g_clear_object (&daemon->rdp_server);
+  g_message ("RDP server stopped");
 }
 #endif /* HAVE_RDP */
 
 #ifdef HAVE_VNC
-static gboolean
-init_vnc_server (GrdDaemon *daemon)
+static void
+start_vnc_server (GrdDaemon *daemon)
 {
   g_autoptr (GError) error = NULL;
-  gboolean result;
+
+  g_assert (!daemon->vnc_server);
 
   daemon->vnc_server = grd_vnc_server_new (daemon->context);
-  if (!(result = grd_vnc_server_start (daemon->vnc_server, &error)))
+  if (!grd_vnc_server_start (daemon->vnc_server, &error))
     g_warning ("Failed to initialize VNC server: %s\n", error->message);
   else
-    g_message ("Initialized VNC server");
-
-  return result;
+    g_message ("VNC server started");
 }
 
 static void
@@ -127,33 +124,29 @@ stop_vnc_server (GrdDaemon *daemon)
   if (!daemon->vnc_server)
     return;
 
-  g_message ("Stopping VNC server");
   grd_vnc_server_stop (daemon->vnc_server);
   g_clear_object (&daemon->vnc_server);
+  g_message ("VNC server stopped");
 }
 #endif /* HAVE_VNC */
 
 static void
 maybe_enable_services (GrdDaemon *daemon)
 {
-  gboolean has_one_backend = FALSE;
+  GrdSettings *settings = grd_context_get_settings (daemon->context);
 
   if (!is_daemon_ready (daemon))
     return;
 
 #ifdef HAVE_RDP
-  has_one_backend = init_rdp_server (daemon) || has_one_backend;
+  if (grd_settings_is_rdp_enabled (settings))
+    start_rdp_server (daemon);
 #endif
 
 #ifdef HAVE_VNC
-  has_one_backend = init_vnc_server (daemon) || has_one_backend;
+  if (grd_settings_is_vnc_enabled (settings))
+    start_vnc_server (daemon);
 #endif
-
-  if (!has_one_backend)
-    {
-      g_warning ("No backend initialized successfully. Exiting");
-      g_application_release (G_APPLICATION (daemon));
-    }
 }
 
 static void
@@ -165,8 +158,6 @@ disable_services (GrdDaemon *daemon)
 #ifdef HAVE_VNC
   stop_vnc_server (daemon);
 #endif
-
-  g_assert (!grd_context_get_sessions (daemon->context));
 }
 
 static void
@@ -268,10 +259,65 @@ on_screen_cast_name_vanished (GDBusConnection *connection,
   grd_context_set_screen_cast_proxy (daemon->context, NULL);
 }
 
+#ifdef HAVE_RDP
+static void
+on_rdp_enabled_changed (GrdSettings *settings,
+                        GrdDaemon   *daemon)
+{
+  if (!is_daemon_ready (daemon))
+    return;
+
+  if (grd_settings_is_rdp_enabled (settings))
+    {
+      g_return_if_fail (!daemon->rdp_server);
+      start_rdp_server (daemon);
+    }
+  else
+    {
+      stop_rdp_server (daemon);
+    }
+}
+#endif /* HAVE_RDP */
+
+#ifdef HAVE_VNC
+static void
+on_vnc_enabled_changed (GrdSettings *settings,
+                        GrdDaemon   *daemon)
+{
+  if (!is_daemon_ready (daemon))
+    return;
+
+  if (grd_settings_is_vnc_enabled (settings))
+    {
+      g_return_if_fail (!daemon->vnc_server);
+      start_vnc_server (daemon);
+    }
+  else
+    {
+      stop_vnc_server (daemon);
+    }
+}
+#endif /* HAVE_VNC */
+
 static void
 grd_daemon_init (GrdDaemon *daemon)
 {
+  GrdSettings *settings;
+
   daemon->context = g_object_new (GRD_TYPE_CONTEXT, NULL);
+
+  settings = grd_context_get_settings (daemon->context);
+
+#ifdef HAVE_RDP
+  g_signal_connect (settings, "rdp-enabled-changed",
+                    G_CALLBACK (on_rdp_enabled_changed),
+                    daemon);
+#endif
+#ifdef HAVE_VNC
+  g_signal_connect (settings, "vnc-enabled-changed",
+                    G_CALLBACK (on_vnc_enabled_changed),
+                    daemon);
+#endif
 }
 
 static void
diff --git a/src/grd-rdp-server.c b/src/grd-rdp-server.c
index 3d986377..41963f9b 100644
--- a/src/grd-rdp-server.c
+++ b/src/grd-rdp-server.c
@@ -146,7 +146,6 @@ on_incoming (GSocketService    *service,
     return TRUE;
 
   rdp_server->sessions = g_list_append (rdp_server->sessions, session_rdp);
-  grd_context_add_session (rdp_server->context, GRD_SESSION (session_rdp));
 
   g_signal_connect (session_rdp, "stopped",
                     G_CALLBACK (on_session_stopped),
diff --git a/src/grd-settings.c b/src/grd-settings.c
index 0d23f70f..c8f28fb4 100644
--- a/src/grd-settings.c
+++ b/src/grd-settings.c
@@ -34,10 +34,12 @@
 
 enum
 {
+  RDP_ENABLED_CHANGED,
   RDP_SCREEN_SHARE_MODE_CHANGED,
   RDP_SERVER_CERT_CHANGED,
   RDP_SERVER_KEY_CHANGED,
   RDP_VIEW_ONLY_CHANGED,
+  VNC_ENABLED_CHANGED,
   VNC_VIEW_ONLY_CHANGED,
   VNC_AUTH_METHOD_CHANGED,
   VNC_ENCRYPTION_CHANGED,
@@ -54,6 +56,7 @@ struct _GrdSettings
   struct {
     GSettings *settings;
 
+    gboolean is_enabled;
     GrdRdpScreenShareMode screen_share_mode;
     char *server_cert;
     char *server_key;
@@ -62,6 +65,7 @@ struct _GrdSettings
   } rdp;
   struct {
     GSettings *settings;
+    gboolean is_enabled;
     gboolean view_only;
     GrdVncAuthMethod auth_method;
     int port;
@@ -220,6 +224,18 @@ grd_settings_get_vnc_view_only (GrdSettings *settings)
   return settings->vnc.view_only;
 }
 
+gboolean
+grd_settings_is_rdp_enabled (GrdSettings *settings)
+{
+  return settings->rdp.is_enabled;
+}
+
+gboolean
+grd_settings_is_vnc_enabled (GrdSettings *settings)
+{
+  return settings->vnc.is_enabled;
+}
+
 GrdVncAuthMethod
 grd_settings_get_vnc_auth_method (GrdSettings *settings)
 {
@@ -236,6 +252,13 @@ update_screen_share_mode (GrdSettings *settings)
     g_settings_get_enum (settings->rdp.settings, "screen-share-mode");
 }
 
+static void
+update_rdp_enabled (GrdSettings *settings)
+{
+  settings->rdp.is_enabled = g_settings_get_boolean (settings->rdp.settings,
+                                                     "enable");
+}
+
 static void
 update_rdp_tls_cert (GrdSettings *settings)
 {
@@ -259,6 +282,13 @@ update_rdp_view_only (GrdSettings *settings)
                                                     "view-only");
 }
 
+static void
+update_vnc_enabled (GrdSettings *settings)
+{
+  settings->vnc.is_enabled = g_settings_get_boolean (settings->vnc.settings,
+                                                     "enable");
+}
+
 static void
 update_vnc_view_only (GrdSettings *settings)
 {
@@ -278,12 +308,17 @@ on_rdp_settings_changed (GSettings   *rdp_settings,
                          const char  *key,
                          GrdSettings *settings)
 {
-  if (strcmp (key, "screen-share-mode") == 0)
+  if (strcmp (key, "enable") == 0)
+    {
+      update_rdp_enabled (settings);
+      g_signal_emit (settings, signals[RDP_ENABLED_CHANGED], 0);
+    }
+  else if (strcmp (key, "screen-share-mode") == 0)
     {
       update_screen_share_mode (settings);
       g_signal_emit (settings, signals[RDP_SCREEN_SHARE_MODE_CHANGED], 0);
     }
-  if (strcmp (key, "tls-cert") == 0)
+  else if (strcmp (key, "tls-cert") == 0)
     {
       update_rdp_tls_cert (settings);
       g_signal_emit (settings, signals[RDP_SERVER_CERT_CHANGED], 0);
@@ -305,7 +340,12 @@ on_vnc_settings_changed (GSettings   *vnc_settings,
                          const char  *key,
                          GrdSettings *settings)
 {
-  if (strcmp (key, "view-only") == 0)
+  if (strcmp (key, "enable") == 0)
+    {
+      update_vnc_enabled (settings);
+      g_signal_emit (settings, signals[VNC_ENABLED_CHANGED], 0);
+    }
+  else if (strcmp (key, "view-only") == 0)
     {
       update_vnc_view_only (settings);
       g_signal_emit (settings, signals[VNC_VIEW_ONLY_CHANGED], 0);
@@ -341,10 +381,12 @@ grd_settings_init (GrdSettings *settings)
   g_signal_connect (settings->vnc.settings, "changed",
                     G_CALLBACK (on_vnc_settings_changed), settings);
 
+  update_rdp_enabled (settings);
   update_screen_share_mode (settings);
   update_rdp_tls_cert (settings);
   update_rdp_tls_key (settings);
   update_rdp_view_only (settings);
+  update_vnc_enabled (settings);
   update_vnc_view_only (settings);
   update_vnc_auth_method (settings);
 
@@ -359,6 +401,13 @@ grd_settings_class_init (GrdSettingsClass *klass)
 
   object_class->finalize = grd_settings_finalize;
 
+  signals[RDP_ENABLED_CHANGED] =
+    g_signal_new ("rdp-enabled-changed",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 0);
   signals[RDP_SCREEN_SHARE_MODE_CHANGED] =
     g_signal_new ("rdp-screen-share-mode-changed",
                   G_TYPE_FROM_CLASS (klass),
@@ -387,6 +436,13 @@ grd_settings_class_init (GrdSettingsClass *klass)
                   0,
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 0);
+  signals[VNC_ENABLED_CHANGED] =
+    g_signal_new ("vnc-enabled-changed",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 0);
   signals[VNC_VIEW_ONLY_CHANGED] =
     g_signal_new ("vnc-view-only-changed",
                   G_TYPE_FROM_CLASS (klass),
diff --git a/src/grd-settings.h b/src/grd-settings.h
index 4ba70cbc..449894ae 100644
--- a/src/grd-settings.h
+++ b/src/grd-settings.h
@@ -30,6 +30,10 @@
 G_DECLARE_FINAL_TYPE (GrdSettings, grd_settings,
                       GRD, SETTINGS, GObject)
 
+gboolean grd_settings_is_rdp_enabled (GrdSettings *settings);
+
+gboolean grd_settings_is_vnc_enabled (GrdSettings *settings);
+
 int grd_settings_get_rdp_port (GrdSettings *settings);
 
 int grd_settings_get_vnc_port (GrdSettings *settings);
diff --git a/src/grd-vnc-server.c b/src/grd-vnc-server.c
index b2531079..633fa858 100644
--- a/src/grd-vnc-server.c
+++ b/src/grd-vnc-server.c
@@ -121,7 +121,6 @@ on_incoming (GSocketService    *service,
 
   session_vnc = grd_session_vnc_new (vnc_server, connection);
   vnc_server->sessions = g_list_append (vnc_server->sessions, session_vnc);
-  grd_context_add_session (vnc_server->context, GRD_SESSION (session_vnc));
 
   g_signal_connect (session_vnc, "stopped",
                     G_CALLBACK (on_session_stopped),
diff --git a/src/org.gnome.desktop.remote-desktop.gschema.xml.in 
b/src/org.gnome.desktop.remote-desktop.gschema.xml.in
index e61e6bc5..939b9a68 100644
--- a/src/org.gnome.desktop.remote-desktop.gschema.xml.in
+++ b/src/org.gnome.desktop.remote-desktop.gschema.xml.in
@@ -2,6 +2,13 @@
   <schema id='org.gnome.desktop.remote-desktop' path='/org/gnome/desktop/remote-desktop/'>
   </schema>
   <schema id='org.gnome.desktop.remote-desktop.rdp' path='/org/gnome/desktop/remote-desktop/rdp/'>
+    <key name='enable' type='b'>
+      <default>false</default>
+      <summary>Whether the RDP backend is enabled or not</summary>
+      <description>
+        If set to to 'true' the RDP backend will be initialized.
+      </description>
+    </key>
     <key name='screen-share-mode' enum='org.gnome.desktop.remote-desktop.GrdRdpScreenShareMode'>
       <default>'mirror-primary'</default>
       <summary>Screenshare mode of RDP connections</summary>
@@ -55,6 +62,13 @@
     </key>
   </schema>
   <schema id='org.gnome.desktop.remote-desktop.vnc' path='/org/gnome/desktop/remote-desktop/vnc/'>
+    <key name='enable' type='b'>
+      <default>false</default>
+      <summary>Whether the VNC backend is enabled or not</summary>
+      <description>
+        If set to to 'true' the VNC backend will be initialized.
+      </description>
+    </key>
     <key name='view-only' type='b'>
       <default>true</default>
       <summary>Only allow remote connections to view the screen content</summary>