cups: remember authentication with Secret Service

Look up and store CUPS authentication information through the Secret Service D-Bus API.

Enable the feature by default when CUPS support is built, requiring the libsecret development files unless explicitly disabled. Keep the print backend free of a runtime libsecret dependency so authentication continues to work when Secret Service is unavailable.

configure.ac

@@ -1538,6 +1538,11 @@ LIBS="$old_LIBS"
 # Printing system checks
 ################################################################
 
+AC_ARG_ENABLE(cups-secret-service,
+              [AS_HELP_STRING([--disable-cups-secret-service]
+                              [disable Secret Service support in the cups print backend])],,
+              [enable_cups_secret_service=yes])
+
 AC_ARG_ENABLE(cups,
               [AS_HELP_STRING([--disable-cups]
                               [disable cups print backend])],,
@@ -1584,6 +1589,17 @@ else
 
     AM_CONDITIONAL(HAVE_CUPS, true)
 
+    if test "x$enable_cups_secret_service" != "xno"; then
+      PKG_CHECK_EXISTS([libsecret-1], [],
+        [AC_MSG_ERROR([
+*** libsecret-1 is required when CUPS Secret Service support is enabled.
+*** Install the libsecret development files or configure
+*** with --disable-cups-secret-service.
+])])
+      AC_DEFINE([HAVE_CUPS_SECRET_SERVICE], [1],
+                [Define to 1 if CUPS Secret Service support is enabled])
+    fi
+
     gtk_save_cflags="$CFLAGS"
     CFLAGS="$CUPS_CFLAGS"
     AC_COMPILE_IFELSE(

gtk/gtkprintbackend.c

@@ -48,8 +48,22 @@ struct _GtkPrintBackendPrivate
   GtkPrintBackendStatus status;
   char **auth_info_required;
   char **auth_info;
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  guint store_auth_info : 1;
+#endif
 };
 
+#ifdef HAVE_CUPS_SECRET_SERVICE
+typedef gboolean (*GtkPrintBackendCanStoreAuthInfoFunc)
+                 (GtkPrintBackend *backend);
+
+typedef void     (*GtkPrintBackendSetPasswordFullFunc)
+                 (GtkPrintBackend  *backend,
+                  gchar           **auth_info_required,
+                  gchar           **auth_info,
+                  gboolean          store_auth_info);
+#endif
+
 enum {
   PRINTER_LIST_CHANGED,
   PRINTER_LIST_DONE,
@@ -459,6 +473,9 @@ gtk_print_backend_init (GtkPrintBackend *backend)
 					  (GDestroyNotify) g_object_unref);
   priv->auth_info_required = NULL;
   priv->auth_info = NULL;
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  priv->store_auth_info = FALSE;
+#endif
 }
 
 static void
@@ -675,6 +692,41 @@ gtk_print_backend_set_password (GtkPrintBackend  *backend,
     GTK_PRINT_BACKEND_GET_CLASS (backend)->set_password (backend, auth_info_required, auth_info);
 }
 
+
+#ifdef HAVE_CUPS_SECRET_SERVICE
+static void
+gtk_print_backend_set_password_full (GtkPrintBackend  *backend,
+                                     gchar           **auth_info_required,
+                                     gchar           **auth_info,
+                                     gboolean          store_auth_info)
+{
+  GtkPrintBackendClass *class;
+
+  class = GTK_PRINT_BACKEND_GET_CLASS (backend);
+
+  if (class->_gtk_reserved2 != NULL)
+    ((GtkPrintBackendSetPasswordFullFunc) class->_gtk_reserved2)
+        (backend,
+         auth_info_required,
+         auth_info,
+         store_auth_info);
+  else
+    gtk_print_backend_set_password (backend,
+                                    auth_info_required,
+                                    auth_info);
+}
+
+
+static void
+store_auth_info_toggled (GtkToggleButton  *button,
+                         GtkPrintBackend  *backend)
+{
+  backend->priv->store_auth_info =
+      gtk_toggle_button_get_active (button);
+}
+#endif
+
+
 static void
 store_entry (GtkEntry  *entry,
              gpointer   user_data)
@@ -698,10 +750,23 @@ password_dialog_response (GtkWidget       *dialog,
   GtkPrintBackendPrivate *priv = backend->priv;
   gint i;
 
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  if (response_id == GTK_RESPONSE_OK)
+    gtk_print_backend_set_password_full (backend,
+                                         priv->auth_info_required,
+                                         priv->auth_info,
+                                         priv->store_auth_info);
+  else
+    gtk_print_backend_set_password_full (backend,
+                                         priv->auth_info_required,
+                                         NULL,
+                                         FALSE);
+#else
   if (response_id == GTK_RESPONSE_OK)
     gtk_print_backend_set_password (backend, priv->auth_info_required, priv->auth_info);
   else
     gtk_print_backend_set_password (backend, priv->auth_info_required, NULL);
+#endif
 
   for (i = 0; i < g_strv_length (priv->auth_info_required); i++)
     if (priv->auth_info[i] != NULL)
@@ -738,10 +803,23 @@ request_password (GtkPrintBackend  *backend,
   gchar    **ai_default = (gchar **) auth_info_default;
   gchar    **ai_display = (gchar **) auth_info_display;
   gboolean  *ai_visible = (gboolean *) auth_info_visible;
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  GtkPrintBackendClass *class;
+  gboolean can_store_auth_info = FALSE;
+#endif
 
   priv->auth_info_required = g_strdupv (ai_required);
   length = g_strv_length (ai_required);
   priv->auth_info = g_new0 (gchar *, length + 1);
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  priv->store_auth_info = FALSE;
+
+  class = GTK_PRINT_BACKEND_GET_CLASS (backend);
+  if (class->_gtk_reserved1 != NULL)
+    can_store_auth_info =
+        ((GtkPrintBackendCanStoreAuthInfoFunc) class->_gtk_reserved1)
+            (backend);
+#endif
 
   dialog = gtk_dialog_new_with_buttons ( _("Authentication"), NULL, GTK_DIALOG_MODAL,
                                          GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
@@ -810,6 +888,18 @@ request_password (GtkPrintBackend  *backend,
         }
     }
 
+#ifdef HAVE_CUPS_SECRET_SERVICE
+  if (can_store_auth_info)
+    {
+      GtkWidget *remember;
+
+      remember = gtk_check_button_new_with_mnemonic (_("_Remember password"));
+      gtk_box_pack_start (GTK_BOX (vbox), remember, FALSE, FALSE, 6);
+      g_signal_connect (remember, "toggled",
+                        G_CALLBACK (store_auth_info_toggled), backend);
+    }
+#endif
+
   if (focus != NULL)
     {
       gtk_widget_grab_focus (focus);