From 4ae5528a62bae5d16c449b22913ce21d02529129 Mon Sep 17 00:00:00 2001
From: Patryk Obara <dreamer.tan@gmail.com>
Date: Mon, 4 May 2020 10:37:03 +0200
Subject: [PATCH] Prevent SDL2 crash on exit when using Wayland

The correct way to cleanup after SDL_Init is to call
"atexit(SDL_Quit);", so all SDL internals are correctly closed, even in
abnormal circumstances.

See: https://wiki.libsdl.org/SDL_Quit

However, when using SDL_VIDEODRIVER=wayland (as of SDL 2.0.12), this
causes crash in SDL, as MESA might've cleaned up some of driver
internals already.

Replace useless SDL_Init_Wrapper with simpler SDL_Init, and create
wrapper for SDL_Quit to accomodate multiple exit scenarios (those
triggered by erros, but also by window managers or directly by users).

Directly call SDL_Quit before atexit queue to prevent crash on normal
process termination (leaving main); the crash was not happening when
process terminates due to exit syscall.
---
 src/gui/sdlmain.cpp | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/gui/sdlmain.cpp b/src/gui/sdlmain.cpp
index a3d267a1..8cb6a85f 100644
--- a/src/gui/sdlmain.cpp
+++ b/src/gui/sdlmain.cpp
@@ -248,7 +248,7 @@ struct Dimensions {
 };
 
 struct SDL_Block {
-	bool inited;
+	bool initialized = false;
 	bool active;							//If this isn't set don't draw
 	bool updating;
 	bool update_display_contents;
@@ -407,12 +407,10 @@ void OPENGL_ERROR(const char*) {
 #endif
 #endif
 
-static int SDL_Init_Wrapper(void)
+static void QuitSDL()
 {
-	// Don't init timers, GetTicks seems to work fine and they can use
-	// a fair amount of power (Macs again).
-	// Please report problems with audio and other things.
-	return SDL_Init(SDL_INIT_AUDIO | SDL_INIT_VIDEO);
+	if (sdl.initialized)
+		SDL_Quit();
 }
 
 extern const char* RunningProgram;
@@ -2887,11 +2885,12 @@ static void show_warning(char const * const message) {
 	fprintf(stderr, "%s", message);
 	return;
 #else
-	if (!sdl.inited && SDL_Init(SDL_INIT_VIDEO|SDL_INIT_NOPARACHUTE) < 0) {
-		sdl.inited = true;
-		printf("%s",message);
+	if (!sdl.initialized && SDL_Init(SDL_INIT_VIDEO) < 0) {
+		sdl.initialized = true;
+		fprintf(stderr, "%s", message);
 		return;
 	}
+
 	if (!sdl.window && !GFX_SetSDLSurfaceWindow(640, 400))
 		return;
 
@@ -2982,7 +2981,7 @@ void restart_program(std::vector<std::string> & parameters) {
 	newargs[parameters.size()] = NULL;
 	MIXER_CloseAudioDevice();
 	SDL_Delay(50);
-	SDL_Quit();
+	QuitSDL();
 #if C_DEBUG
 	// shutdown curses
 	DEBUG_ShutDown(NULL);
@@ -3181,11 +3180,11 @@ int main(int argc, char* argv[]) {
 	LOG_MSG("dosbox-staging version %s", VERSION);
 	LOG_MSG("---");
 
-	if (SDL_Init_Wrapper() < 0)
+	if (SDL_Init(SDL_INIT_AUDIO | SDL_INIT_VIDEO) < 0)
 		E_Exit("Can't init SDL %s", SDL_GetError());
-	sdl.inited = true;
+	sdl.initialized = true;
 	// Once initialized, ensure we clean up SDL for all exit conditions
-	atexit(SDL_Quit);
+	atexit(QuitSDL);
 
 	sdl.laltstate = SDL_KEYUP;
 	sdl.raltstate = SDL_KEYUP;
@@ -3297,9 +3296,16 @@ int main(int argc, char* argv[]) {
 		// just exit
 		rcode = 1;
 	}
+
 #if defined (WIN32)
 	sticky_keys(true); //Might not be needed if the shutdown function switches to windowed mode, but it doesn't hurt
 #endif
+
+	// We already do this at exit, but do cleanup earlier in case of normal
+	// exit; this works around problems when atexit order clashes with SDL2
+	// cleanup order. Happens with SDL_VIDEODRIVER=wayland as of SDL 2.0.12.
+	QuitSDL();
+
 	return rcode;
 }