When WirePlumber exits, it crashes with SIGABRT. The backtrace shows:
7 g_closure_invalidate
10 g_object_unref
15 g_value_unset
16 _wplua_gvalue_userdata___gc
26 close_state (lua_close)
27 wp_plugin_deactivate
33 wp_registry_clear
34 wp_core_dispose
Root cause: lua_State is referenced by both the main plugin and each
WpLuaScript object. During registry cleanup, scripts call lua_close again
on an already-destroyed state, causing use-after-free.
Fix:
- Add a prepare_shutdown vfunc in WpPlugin. Call it from wp_core_dispose
*before* clearing the registry.
- Lua plugin implements prepare_shutdown to close its lua_State early,
allowing all __gc finalizers to run while GObjects are still alive.
- Then clear the lua_State pointer from every WpLuaScript object via
wp_lua_script_clear_lua_state().
- Guard WpLuaScript finalize to skip if pointer is already NULL.
This allows registering arbitrary objects on the core's registry and
finding them later, without having to add API for each and every object.
I think this is useful enough to have it public, even though it's
probably not going to be used that much... The rationale here is to
allow registering custom component loaders without having to make them
subclass WpPlugin or to create custom API for registering component
loaders specifically.
Also, remove the wp_plugin_register() and wp_si_factory_register()
functions, since they are not going to be used much in the future.
The idea is to let the component loader do the registration under the
scenes, as the component is getting loaded.
Aim for 8 pointers on each struct, wich exceptions:
- 12 pointers for already crowded/important ones
- 4 pointers for empty ones that are used for proxies; we are
unlikely to add any virtual methods on these classes ever
* use the activate/deactivate system from WpObject,
which allows async activation and error reporting
* drop 'module' property, use 'core' from WpObject
After discussing things at the AGL May 2019 F2F meeting
and reflecting on the initial design of WirePlumber,
it became clear that it needed a fresh start.
