malloc detour using minhook (CRT override)

lib.cpp

#include "lib.h"

#include "../3rd/minhook/include/MinHook.h"
#include "../3rd/minhook/src/buffer.c"
#include "../3rd/minhook/src/hook.c"
#include "../3rd/minhook/src/trampoline.c"
#include "../3rd/minhook/src/hde/hde64.c"

typedef void* (*fn_malloc)(size_t size);
typedef void  (*fn_free)(void* ptr);
typedef void* (*fn_realloc)(void* ptr, size_t size);
typedef void* (*fn_calloc)(size_t num, size_t size);

// These macros are copied from rmem: https://github.com/RudjiGames/rmem/blob/240defd1b0dba5c95dbc67414f72346a7b6bbda1/src/rmem_wrap_win.cpp#L290
#define FN_ORIGINAL(name)			\
	fn_##name fn_##name##_t;

#define CALL_ORIGINAL(name)			\
	fn_##name##_t

#define GET_PROC_ADDRESS(hmodule, name)									\
	( (fn_##name)(::GetProcAddress(hmodule, #name)) )

#define CREATE_HOOK(hmodule, name)										\
		MH_CreateHook((void*)GET_PROC_ADDRESS(hmodule, name), (void*)&detour_##name, (void **)&(CALL_ORIGINAL(name)));

#define REMOVE_HOOK(hmodule, name)										\
		MH_RemoveHook((void*)GET_PROC_ADDRESS(hmodule, name));

FN_ORIGINAL(malloc)
FN_ORIGINAL(free)
FN_ORIGINAL(realloc)
FN_ORIGINAL(calloc)


// Detour function for malloc
void* detour_malloc(size_t size)
{
	void* ret = (CALL_ORIGINAL(malloc)(size));
    // Custom Code
	return ret;
}

// Detour function for free
void detour_free(void* ptr)
{
    // Custom Code
	CALL_ORIGINAL(free)(ptr);
}

// Detour function for realloc
void* detour_realloc(void* ptr, size_t size)
{
	void* ret = CALL_ORIGINAL(realloc)(ptr, size);
    // Custom Code
	return ret;
}

// Detour function for calloc
void* detour_calloc(size_t num, size_t size)
{
	void* ret = CALL_ORIGINAL(calloc)(num, size);
    // Custom Code
	return ret;
}

namespace memory_profiling
{
	void hookAllocs()
	{
#if defined(_DEBUG)
		HMODULE hUCRT = ::GetModuleHandleA("ucrtbased.dll");
#else
		HMODULE hUCRT = ::GetModuleHandleA("ucrtbase.dll");
#endif
		MH_Initialize();

		CREATE_HOOK(hUCRT, malloc);
		CREATE_HOOK(hUCRT, free);
		CREATE_HOOK(hUCRT, realloc);
		CREATE_HOOK(hUCRT, calloc);

		MH_EnableHook(MH_ALL_HOOKS);
	}

	void unhookAllocs()
	{
#if defined(_DEBUG)
		HMODULE hUCRT = ::GetModuleHandleA("ucrtbased.dll");
#else
		HMODULE hUCRT = ::GetModuleHandleA("ucrtbase.dll");
#endif
		REMOVE_HOOK(hUCRT, malloc);
		REMOVE_HOOK(hUCRT, free);
		REMOVE_HOOK(hUCRT, realloc);
		REMOVE_HOOK(hUCRT, calloc);

		MH_Uninitialize();
	}
}