[gdm/wip/re-read-config: 1/2] common: Add API to reload settings from disk

[Ray Strode <halfline src gnome org>]

commit 100685cd50d62e88cbe11cc8dfe15c3047a9d7ce
Author: Ray Strode <rstrode redhat com>
Date:   Tue Feb 15 14:33:22 2022 -0500

    common: Add API to reload settings from disk
    
    Ideally we would reread /run/gdm/custom.conf after systemd says
    graphics setup is complete.  This is because the file may not
    get written out until after GDM is already started and waiting.
    
    As a first step to get there, this commit adds an API for rereading
    the file, and changes the SIGHUP handler to use it (instead of
    the complete teardown and reinitialization it was doing before).

 common/gdm-settings-direct.c |  9 +++++++++
 common/gdm-settings-direct.h |  2 ++
 common/gdm-settings.c        | 14 ++++++++++++--
 common/gdm-settings.h        |  1 +
 daemon/main.c                | 12 ++----------
 5 files changed, 26 insertions(+), 12 deletions(-)
---
diff --git a/common/gdm-settings-direct.c b/common/gdm-settings-direct.c
index ddb31908e..5fbe0326d 100644
--- a/common/gdm-settings-direct.c
+++ b/common/gdm-settings-direct.c
@@ -251,6 +251,15 @@ gdm_settings_direct_init (GdmSettings *settings,
         return TRUE;
 }
 
+void
+gdm_settings_direct_reload (void)
+{
+    if (!settings_object)
+            return;
+
+    gdm_settings_reload (settings_object);
+}
+
 void
 gdm_settings_direct_shutdown (void)
 {
diff --git a/common/gdm-settings-direct.h b/common/gdm-settings-direct.h
index 156489cd8..6754955f1 100644
--- a/common/gdm-settings-direct.h
+++ b/common/gdm-settings-direct.h
@@ -30,6 +30,8 @@ G_BEGIN_DECLS
 gboolean              gdm_settings_direct_init                       (GdmSettings       *settings,
                                                                       const char        *schemas_file,
                                                                       const char        *root);
+
+void                  gdm_settings_direct_reload                     (void);
 void                  gdm_settings_direct_shutdown                   (void);
 
 gboolean              gdm_settings_direct_get                        (const char        *key,
diff --git a/common/gdm-settings.c b/common/gdm-settings.c
index e6f46ec35..96c2f8d3e 100644
--- a/common/gdm-settings.c
+++ b/common/gdm-settings.c
@@ -184,12 +184,16 @@ backend_value_changed (GdmSettingsBackend *backend,
         g_signal_emit (settings, signals [VALUE_CHANGED], 0, key, old_value, new_value);
 }
 
-static void
-gdm_settings_init (GdmSettings *settings)
+void
+gdm_settings_reload (GdmSettings *settings)
 {
         GList *l;
         GdmSettingsBackend *backend;
 
+        g_list_foreach (settings->backends, (GFunc) g_object_unref, NULL);
+        g_list_free (settings->backends);
+        settings->backends = NULL;
+
         backend = gdm_settings_desktop_backend_new (GDM_CUSTOM_CONF);
         if (backend)
                 settings->backends = g_list_prepend (NULL, backend);
@@ -208,6 +212,12 @@ gdm_settings_init (GdmSettings *settings)
         }
 }
 
+static void
+gdm_settings_init (GdmSettings *settings)
+{
+        gdm_settings_reload (settings);
+}
+
 static void
 gdm_settings_finalize (GObject *object)
 {
diff --git a/common/gdm-settings.h b/common/gdm-settings.h
index 786868a94..2152cb3fd 100644
--- a/common/gdm-settings.h
+++ b/common/gdm-settings.h
@@ -40,6 +40,7 @@ typedef enum
 GQuark              gdm_settings_error_quark                    (void);
 
 GdmSettings *       gdm_settings_new                            (void);
+void                gdm_settings_reload                         (void);
 
 /* exported */
 
diff --git a/daemon/main.c b/daemon/main.c
index 1b893fe0f..344d1b74d 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -267,16 +267,8 @@ static gboolean
 on_sighup_cb (gpointer user_data)
 {
         g_debug ("Got HUP signal");
-        /* Reread config stuff like system config files, VPN service
-         * files, etc
-         */
-        g_object_unref (settings);
-        settings = gdm_settings_new ();
-        if (settings != NULL) {
-                if (! gdm_settings_direct_init (settings, DATADIR "/gdm/gdm.schemas", "/")) {
-                        g_warning ("Unable to initialize settings");
-                }
-        }
+
+        gdm_settings_reload (settings);
 
         return TRUE;
 }