thcrap_loader hangs on Wine

[tactikauan]

The thcrap_loader process keeps running after closing the game on Wine. The issue is present since the 2023-08-17 release and affects all versions of Wine/Proton.

From my debugging, this thread seems to get stuck:

thcrap/thcrap_update/src/loader_update.cpp

Line 712 in bc6d09f

HANDLE hWrapperUpdateThread = CreateThread(NULL, 0, update_wrapper_patch, &state, 0, NULL);

Looking at the function, it gets blocked on this call to ReadFile:

thcrap/thcrap_update/src/loader_update.cpp

Lines 600 to 604 in bc6d09f

	for (;;) {
	char json_data[1024] = {};
	ReadFile(hMail, json_data, sizeof(json_data), nullptr, &overlapped);
	DWORD signal = WaitForMultipleObjects(3, handles, FALSE, INFINITE);
	json_t* json_data_ = json_loads(json_data, 0, nullptr);

Apparently Wine doesn't support async reads on mailslots.

[32th-System]

Damn. A developer suggested having one single shared buffer to keep all the data shared between multiple processes, and signaling the update_wrapper_patch using an event, rather than relying on the mailslot system. I guess we'll have to do this after all