Add stuff to track keypresses

Committer's note: this is somewhat adapted from Bill's original code,
written a while back, but he gets full credit for actually doing the
hard part.

1 files changed, 106 insertions, 0 deletions

diff --git a/src/ac.c b/src/ac.c
index f5451de..2a1a8a4 100644
--- a/src/ac.c
+++ b/src/ac.c
@@ -1,5 +1,6 @@
 /*
  * Copyright © 2022 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2022 Willian Henrique <wsimanbrazil@yahoo.com.br>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -17,6 +18,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 
+#include "bind.h"
 #include "con_.h"
 #include "hook.h"
 #include "engineapi.h"
@@ -25,6 +27,9 @@
 #include "mem.h"
 #include "os.h"
 #include "ppmagic.h"
+#include "vcall.h"
+#include "x86.h"
+#include "x86util.h"
 
 static bool lockdown = false;
 
@@ -134,17 +139,118 @@ static void endlockdown(void) {
 	lockdown = false;
 }
 
+enum /* from InputEventType_t - terser names used here */ {
+	BTNDOWN = 0, // data contains button code
+	BTNUP, // "
+	BTNDOUBLECLICK, // "
+	ANALOGUEVALCHG, // data contains analogue code, data2 contains value
+	SYSQUIT = 100,
+	SYSCTRLHOTPLUG, // data contains controller ID
+	SYSCTRLCOLDPLUG, // "
+	// ranges for other things
+	FIRSTVGUIEV = 1000,
+	FIRSTAPPEV = 2000
+};
+
+struct inputevent {
+	int type; // above enum
+	int tick;
+	int data, data2, data3;
+};
+
+DECL_VFUNC_DYN(void, GetDesktopResolution, int *, int *)
+DECL_VFUNC_DYN(void, DispatchAllStoredGameMessages)
+
+typedef void (*VCALLCONV DispatchInputEvent_func)(void *, struct inputevent *);
+static DispatchInputEvent_func orig_DispatchInputEvent;
+static void VCALLCONV hook_DispatchInputEvent(void *this,
+		struct inputevent *ev) {
+	// TODO(rta): do something here! (here's a quick reference/example)
+	//switch (ev->type) {
+	//	CASES(BTNDOWN, BTNUP, BTNDOUBLECLICK):
+	//		const char *desc[] = {"DOWN", "UP", "DOUBLE"};
+	//		const char *binding = bind_get(ev->data);
+	//		if (!binding) binding = "[unbound]";
+	//		con_msg("key %d %s => %s\n", ev->data, desc[ev->type - BTNDOWN],
+	//					binding);
+	//}
+	orig_DispatchInputEvent(this, ev);
+}
+
+static bool find_DispatchInputEvent(void) {
+#ifdef _WIN32
+	// Crazy pointer-chasing path to get to DispachInputEvent (to log keypresses
+	// and their associated binds):
+	// IGameUIFuncs interface
+	// -> CGameUIFuncs::GetDesktopResolution vfunc
+	//  -> IGame/CGame (first mov into ECX)
+	//   -> CGame::DispatchAllStoredGameMessages vfunc
+	//    -> DispatchInputEvent (first call instruction)
+	void *gameuifuncs = factory_engine("VENGINE_GAMEUIFUNCS_VERSION005", 0);
+	if (!gameuifuncs) {
+		errmsg_errorx("couldn't get engine game UI interface");
+		return false;
+	}
+	void *cgame;
+	GetDesktopResolution_func GetDesktopResolution =
+			VFUNC(gameuifuncs, GetDesktopResolution);
+	for (uchar *p = (uchar *)GetDesktopResolution;
+			p - (uchar *)GetDesktopResolution < 16;) {
+		if (p[0] == X86_MOVRMW && p[1] == X86_MODRM(0, 1, 5)) {
+			void **indirect = mem_loadptr(p + 2);
+			cgame = *indirect;
+			goto ok;
+		}
+		NEXT_INSN(p, "CGame instance pointer");
+	}
+	errmsg_errorx("couldn't find pointer to CGame instance");
+	return false;
+ok:	DispatchAllStoredGameMessages_func DispatchAllStoredGameMessages =
+			VFUNC(cgame, DispatchAllStoredGameMessages);
+	for (uchar *p = (uchar *)DispatchAllStoredGameMessages;
+			p - (uchar *)DispatchAllStoredGameMessages < 128;) {
+		if (p[0] == X86_CALL) {
+			orig_DispatchInputEvent = (DispatchInputEvent_func)(p + 5 +
+					mem_loadoffset(p + 1));
+			// Note: we could go further and dig HandleEngineKey from Key_Event,
+			// but it seems like Key_Event isn't directly called from
+			// DispatchInputEvent in L4D2 (or has a much different structure,
+			// requiring another function call to lead to HandleEngineKey).
+			return true;
+		}
+		NEXT_INSN(p, "DispatchInputEvent function");
+	}
+	errmsg_errorx("couldn't find DispatchInputEvent function");
+#else
+#warning TODO(linux): more find-y stuff
+#endif
+	return false;
+}
+
 bool ac_init(void) {
+	if (!has_vtidx_GetDesktopResolution ||
+			!has_vtidx_DispatchAllStoredGameMessages) {
+		errmsg_errorx("missing gamedata entries for this engine");
+		return false;
+	}
 #if defined(_WIN32)
 	if (!win32_init()) return false;
 #elif defined(__linux__)
 	// TODO(linux): call init things
 #endif
+	if (!find_DispatchInputEvent()) return false;
+	orig_DispatchInputEvent = (DispatchInputEvent_func)hook_inline(
+			(void *)orig_DispatchInputEvent, (void *)&hook_DispatchInputEvent);
+	if (!orig_DispatchInputEvent) {
+		errmsg_errorsys("couldn't hook DispatchInputEvent function");
+		return false;
+	}
 	return true;
 }
 
 void ac_end(void) {
 	endlockdown();
+	unhook_inline((void *)orig_DispatchInputEvent);
 }
 
 // vi: sw=4 ts=4 noet tw=80 cc=80