Version 1.08 with public source code release.

src/main/hook/patch/main-loop.h

@@ -0,0 +1,59 @@
+/**
+ * This module fixes different things on the main loop of the game.
+ *
+ * First, it hooks into the X11 event loop to grab and dispatch inputs for
+ * further IO hooks or input emulation.
+ *
+ * The second thing is quite stupid and fixes crashing on newer kernels
+ * because AM used sigalarm to drive certain parts of their engine.
+ * This only applies to one generation of the game engine which includes the
+ * releases: Exceed, Exceed2, Zero and NX
+ *
+ * Detailed analysis:
+ *
+ * AM decided to poll the CPIU::Update function which contains updating
+ * the render state as well as decoding sound data, using the signal SIGALRM.
+ * This signal is triggered periodically and drives the whole engine.
+ * But, starting kernel versions newer than 2.4.27 something changed which
+ * causes the game to deadlock an _ALL_ kernels newer than said version. Trying
+ * to fix the deadlock issue makes things even worse and only introduces
+ * segfaults with random crashes. So this is not the right approach.
+ * Starting NX2 AM used a newer kernel and apparently got the same problem
+ * with their OS. They fixed it by moving music_send_data from CPIU::Update()
+ * to the IO thread. Splitting CPIU::Update that way, this seems to work fine.
+ * However, trying this with the old games lacking the patch, we are getting
+ * segfaults (again).
+ * It looks like there is an issue with firing and/or handling of SIGALRM in
+ * another thread than the main thread (don't ask me why). This leads to the
+ * solution of the problem: moving the call of CPIU::Update()to the main
+ * thread which is only pumping XEvents (i.e. nothing).
+ * So let's give the main thread some work: Detouring XPending and calling
+ * the registered signal handler for SIGALRM of the game in there and muting
+ * signal handling for SIGALRM. This solves all deadlocking and segfault
+ * issues which are related to audio playback in combination with decoding a
+ * video.
+ */
+#ifndef PATCH_MAIN_LOOP_H
+#define PATCH_MAIN_LOOP_H
+
+#include <stdbool.h>
+#include <X11/Xutil.h>
+
+/**
+ * Initialize the patch module
+ *
+ * @param fix_sigalarm_main_loop True to enable the sigalarm thread fix (doc see above)
+ * @param disable_built_in_inputs Disable the built in keyboard inputs for test (F1), service (F2) and clear (F3)
+ * @param disable_mk3_linux_port_inputs Disable the built-in keyboard inputs on the MK3 linux ports
+ */
+void patch_main_loop_init(bool fix_sigalarm_main_loop, bool disable_built_in_inputs,
+    bool disable_mk3_linux_port_inputs);
+
+/**
+ * Register a handler (multiple possible) to receive X11 input events, e.g. key pressed, released
+ *
+ * @param lib_with_handler_impl Path to a library implementing the x11-input-handler API
+ */
+void patch_main_loop_add_x11_input_handler(const char* lib_with_handler_impl);
+
+#endif