[virt-tools-list] [PATCH virt-viewer v2] iso-dialog: Avoid crash when closing dialog early

[Eduardo Lima (Etrunko)]

On 09/02/17 17:19, Pavel Grunt wrote:
> Hi Eduardo,
> 
> On Thu, 2017-02-09 at 15:13 -0200, Eduardo Lima (Etrunko) wrote:
>> We must take into account that users can close the dialog at
>> anytime,
>> even during an operation of fetch or set ISO has not been finished.
>> This
>> will cause the callbacks for those operations to be invoked with an
>> invalid object, crashing the application.
>>
>> To fix this issue we need to pass a GCancellable to the asynchronous
>> operations, so they can be cancelled if the dialog happens to get
>> closed
>> before they complete.
>>
>> Signed-off-by: Eduardo Lima (Etrunko) <etrunko at redhat.com>
>> ---
>> v2:
>>  * Move call to g_cancellable_cancel() to response handler.
>>  * Don't leak error objects if operation is cancelled.
>> ---
>>  src/remote-viewer-iso-list-dialog.c | 42
>> ++++++++++++++++++++++++++++++-------
>>  1 file changed, 34 insertions(+), 8 deletions(-)
>>
>> diff --git a/src/remote-viewer-iso-list-dialog.c b/src/remote-
>> viewer-iso-list-dialog.c
>> index 2ab5435..ed51ffa 100644
>> --- a/src/remote-viewer-iso-list-dialog.c
>> +++ b/src/remote-viewer-iso-list-dialog.c
>> @@ -42,6 +42,7 @@ struct _RemoteViewerISOListDialogPrivate
>>      GtkWidget *stack;
>>      GtkWidget *tree_view;
>>      OvirtForeignMenu *foreign_menu;
>> +    GCancellable *cancellable;
>>  };
>>  
>>  enum RemoteViewerISOListDialogModel
>> @@ -66,6 +67,8 @@ remote_viewer_iso_list_dialog_dispose(GObject
>> *object)
>>      RemoteViewerISOListDialog *self =
>> REMOTE_VIEWER_ISO_LIST_DIALOG(object);
>>      RemoteViewerISOListDialogPrivate *priv = self->priv;
>>  
>> +    g_clear_object(&priv->cancellable);
>> +
>>      if (priv->foreign_menu) {
>>          g_signal_handlers_disconnect_by_data(priv->foreign_menu,
>> object);
>>          g_clear_object(&priv->foreign_menu);
>> @@ -157,17 +160,24 @@ fetch_iso_names_cb(OvirtForeignMenu
>> *foreign_menu,
>>          const gchar *msg = error ? error->message : _("Failed to
>> fetch CD names");
>>          gchar *markup = g_strdup_printf("<b>%s</b>", msg);
>>  
>> +        g_debug("Error fetching ISO names: %s", msg);
>> +        if (error && error->code == G_IO_ERROR_CANCELLED)
> use g_error_matches if possible
> 
>> +            goto end;
>> +
>>          gtk_label_set_markup(GTK_LABEL(priv->status), markup);
>>          gtk_spinner_stop(GTK_SPINNER(priv->spinner));
>>          remote_viewer_iso_list_dialog_show_error(self, msg);
>>          gtk_dialog_set_response_sensitive(GTK_DIALOG(self),
>> GTK_RESPONSE_NONE, TRUE);
>>          g_free(markup);
>> -        g_clear_error(&error);
>> -        return;
>> +        goto end;
>>      }
>>  
>> +    g_clear_object(&priv->cancellable);
>>      g_list_foreach(iso_list, (GFunc)
>> remote_viewer_iso_list_dialog_foreach, self);
>>      remote_viewer_iso_list_dialog_show_files(self);
>> +
>> +end:
>> +    g_clear_error(&error);
>>  }
>>  
>>  
>> @@ -177,7 +187,10 @@
>> remote_viewer_iso_list_dialog_refresh_iso_list(RemoteViewerISOListDi
>> alog *self)
>>      RemoteViewerISOListDialogPrivate *priv = self->priv;
>>  
>>      gtk_list_store_clear(priv->list_store);
>> -    ovirt_foreign_menu_fetch_iso_names_async(priv->foreign_menu,
>> NULL,
>> +
>> +    priv->cancellable = g_cancellable_new();
>> +    ovirt_foreign_menu_fetch_iso_names_async(priv->foreign_menu,
>> +                                             priv->cancellable,
>>                                               (GAsyncReadyCallback)
>> fetch_iso_names_cb,
>>                                               self);
>>  }
>> @@ -190,8 +203,10 @@
>> remote_viewer_iso_list_dialog_response(GtkDialog *dialog,
>>      RemoteViewerISOListDialog *self =
>> REMOTE_VIEWER_ISO_LIST_DIALOG(dialog);
>>      RemoteViewerISOListDialogPrivate *priv = self->priv;
>>  
>> -    if (response_id != GTK_RESPONSE_NONE)
>> +    if (response_id != GTK_RESPONSE_NONE) {
>> +        g_cancellable_cancel(priv->cancellable);
>>          return;
>> +    }
>>  
>>      gtk_spinner_start(GTK_SPINNER(priv->spinner));
>>      gtk_label_set_markup(GTK_LABEL(priv->status),
>> _("<b>Loading...</b>"));
>> @@ -223,7 +238,9 @@
>> remote_viewer_iso_list_dialog_toggled(GtkCellRendererToggle
>> *cell_renderer G_GNU
>>      gtk_dialog_set_response_sensitive(GTK_DIALOG(self),
>> GTK_RESPONSE_NONE, FALSE);
>>      gtk_widget_set_sensitive(priv->tree_view, FALSE);
>>  
>> -    ovirt_foreign_menu_set_current_iso_name_async(priv-
>>> foreign_menu, active ? NULL : name, NULL,
>> +    priv->cancellable = g_cancellable_new();
>> +    ovirt_foreign_menu_set_current_iso_name_async(priv-
>>> foreign_menu, active ? NULL : name,
>> +                                                  priv-
>>> cancellable,
>>                                                    (GAsyncReadyCallb
>> ack)ovirt_foreign_menu_iso_name_changed,
>>                                                    self);
>>      gtk_tree_path_free(tree_path);
>> @@ -308,12 +325,18 @@
>> ovirt_foreign_menu_iso_name_changed(OvirtForeignMenu *foreign_menu,
>>       * change the ISO back to the original, avoiding a possible
>> inconsistency.
>>       */
>>      if
>> (!ovirt_foreign_menu_set_current_iso_name_finish(foreign_menu,
>> result, &error)) {
>> -        remote_viewer_iso_list_dialog_show_error(self, error ?
>> error->message : _("Failed to change CD"));
>> -        g_clear_error(&error);
>> +        const gchar *msg = error ? error->message : _("Failed to
>> change CD");
>> +        g_debug("Error changing ISO: %s", msg);
>> +
>> +        if (error && error->code == G_IO_ERROR_CANCELLED)
> 
> g_error_matches
> 
>> +            goto end;
>> +
>> +        remote_viewer_iso_list_dialog_show_error(self, msg);
>>      }
>>  
>> +    g_clear_object(&priv->cancellable);
>>      if (!gtk_tree_model_get_iter_first(model, &iter))
>> -        return;
>> +        goto end;
>>  
>>      current_iso =
>> ovirt_foreign_menu_get_current_iso_name(foreign_menu);
>>  
>> @@ -340,6 +363,9 @@
>> ovirt_foreign_menu_iso_name_changed(OvirtForeignMenu *foreign_menu,
>>      gtk_dialog_set_response_sensitive(GTK_DIALOG(self),
>> GTK_RESPONSE_NONE, TRUE);
>>      gtk_widget_set_sensitive(priv->tree_view, TRUE);
>>      g_free(current_iso);
>> +
>> +end:
>> +    g_clear_error(&error);
>>  }
>>  
>  GtkWidget *
> 
> I haven't test it, but it looks good, ack with the g_error_matches
> change

Thanks, it has been pushed with the changes you suggested.


-- 
Eduardo de Barros Lima (Etrunko)
Software Engineer - RedHat
etrunko at redhat.com