libsecret and dlopen/dlclose thread cleanup, dlopen freeze

[Gábor Csárdi <csardi gabor+gtk-list gmail com>]

Hi all,

I have a plugin that uses libsecret, and thus glib, on Linux. (It is a package for R.)

It is loaded with dlopen(), and it (ideally) can be unloaded with dlclose(). I use the synchronous libsecret functions, which AFAICT run a temporary glib event loop for each libsecret query. E.g. this is what I am doing:

  GError *err = NULL;

  

  gchar *password = secret_password_lookup_sync (

    keyring_secret_service_schema(),

    /* cancellable = */ NULL,

    &err,

    "service", cservice,

    "username", cusername,

    NULL);

  if (err) {

    if (password) secret_password_free(password);

    keyring_secret_service_handle_status("get", TRUE, err);

  }

  if (!password) {

    error("keyring item not found");

    return R_NilValue;

  } else {

    secret_password_free(password);

    /* ... */

    return result;

  }

When the lib is unloaded I call secret_service_disconnect(), I checked that this is called. I do link to libgobject-2.0, I even call g_type_ensure (G_TYPE_OBJECT) to make sure that the constructors in libgobject run.

However, it seems that the worker threads for glib (?) are never cleaned up. Even if I dlclose() the lib, they are there. What am I missing here? Do I have to eliminate the threads manually? If yes, how can I do that?

An even bigger problem is, that if I dlopen() the same plugin again, and call a libsecret function, then it just freezes with this:

(process:18663): GLib-GObject-WARNING **: cannot register existing type 'SecretService'

(process:18663): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed

(process:18663): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed

(process:18663): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(process:18663): GLib-GIO-CRITICAL **: g_async_initable_new_valist_async: assertion 'G_TYPE_IS_ASYNC_INITABLE (object_type)' failed

Which seems to suggest that I need to unregister the SecretService type at dlclose(). Is that right? How can I do that?

I don't have too much experience with glib, and I am just probably doing something wrong, or missing something. Any help is appreciated. I can also put together a reproducible example if needed.

Thanks, Best,

Gabor