HookFunction

#define UNLOCKED 0x0#define LOCKED	0xffffffff__declspec(naked) void HookFunction(){	__asm	{		pushf //4 bytes		pusha //8 * 4 bytes = 32 bytes				//Inlined TlsGetValue:		mov		ebx,	fs:0x18 //Get linear address of ThreadInformationBlock (file:///N:/reference.html#ThreadInformationBlock)		mov		ecx,	[tlsIndex]		mov		eax,	[ebx + ecx*4 + 0xe10]checkSemaphore:		cmp		eax,	LOCKED		jz		execute		//set the semaphore:		mov		eax,					LOCKED 		mov		[ebx + ecx*4 + 0xe10],	eaxlog:		//Do actual logging via lookup table		//Don't forget to retrieve 'stack-size' of hooked function for use in stack-shift.shiftstack:				add		esp,	0x4 //add some more space for a copy of return address of the target.		mov		ecx,	0xa //flags + registers + the a return address TODO: Add number of args.		mov		edi,	esp		sub		edi,	0x2c		mov		esi,	edi		mov		eax,	esi //Keep a copy of the original esp in eax.		sub		esi,	0x4		rep		movs	edi,	esi 				//We've now shifted the entire 'state block' down on the stack, creating a void.		/* In addition, in this instance, the data we want in the 'void' 		 * (our target's return address)		 * is already there ;)		 */		//now overwrite the return address to come back to returnHandler so we can unlock the hook.		mov		[eax],		returnHandler	execute:		//restore state:		popa		popf		//Execute the overwritten prolog:		push	ebp		mov		ebp,	esp		//return to the function:		retreturnHandler:		pushf		pusha		//Inlined TlsGetValue:		mov		ebx,	fs:0x18 //Get linear address of ThreadInformationBlock (file:///N:/reference.html#ThreadInformationBlock)		mov		ecx,	[tlsIndex]		//set the semaphore:		mov		eax,					UNLOCKED 		mov		[ebx + ecx*4 + 0xe10],	eax		popf		popa		ret //to the original caller!	}}