/********************************************************/

/*  ntapi: Native API core library                      */

/*  Copyright (C) 2013--2021  Z. Gilboa                 */

/*  Released under GPLv2 and GPLv3; see COPYING.NTAPI.  */

/********************************************************/

#include <psxtypes/psxtypes.h>

#include <ntapi/nt_object.h>

#include <ntapi/nt_debug.h>

#include "ntapi_impl.h"

static int32_t __tt_debug_break_process_fail(void * hthread, int32_t status)

{

	__ntapi->zw_terminate_thread(

		hthread,status);

	return status;

}

struct __dbg_hoppla {

	void *		caller;

	void *		cx;

	intptr_t	dx;

	intptr_t	r9;

	intptr_t	r8;

};

int32_t __stdcall __ntapi_tt_debug_break_process(

	__in	void *		hprocess,

	__out	void **		hthread,

	__out	nt_cid *	cid)

{

	int32_t			status;

	nt_thread_params	tparams;

	nt_thread_context	context;

	nt_user_stack		spinfo;

	struct __dbg_hoppla	hoppla;

	uintptr_t		sptop;

	uintptr_t		spreg;

	int32_t			(__stdcall *dbg_break_point)(void *);

	/* interrupt & return */

	dbg_break_point = pe_get_procedure_address(

		pe_get_ntdll_module_handle(),

		"DbgBreakPoint");

	/* thread params */

	__ntapi->tt_aligned_block_memset(

		&tparams,0,

		sizeof(tparams));

	__ntapi->tt_aligned_block_memset(

		&spinfo,0,

		sizeof(spinfo));

	tparams.start              = dbg_break_point;

	tparams.hprocess           = hprocess;

	tparams.stack_size_commit  = 0x1000;

	tparams.stack_size_reserve = 0x1000;

	tparams.stack_info         = &spinfo;

	tparams.creation_flags     = NT_CREATE_SUSPENDED;

	if ((status = __ntapi->tt_create_thread(&tparams)))

		return status;

	/* context */

	__ntapi->tt_aligned_block_memset(

		&context,0,

		sizeof(context));

	context.uc_context_flags = NT_CONTEXT_JUST_EVERYTHING;

	if ((status = __ntapi->zw_get_context_thread(

			tparams.hthread,

			&context)))

		return __tt_debug_break_process_fail(

			tparams.hthread,

			status);

	/* return address:=) */

	hoppla.caller = __ntapi->zw_terminate_thread;

	hoppla.cx     = NT_CURRENT_THREAD_HANDLE;

	hoppla.dx     = NT_STATUS_BREAKPOINT;

	hoppla.r8     = 0;

	hoppla.r9     = 0;

	sptop = (uintptr_t)tparams.stack_info->expandable_stack_base;

	spreg = context.STACK_POINTER_REGISTER;

	if (sptop - spreg < sizeof(hoppla))

		spreg -= sizeof(hoppla);

	if ((status = __ntapi->zw_write_virtual_memory(

			hprocess,

			(void *)spreg,

			(char *)&hoppla,

			sizeof(hoppla),0)))

		return __tt_debug_break_process_fail(

			tparams.hthread,

			status);

	/* (fast call args not needed on x86) */

	context.STACK_POINTER_REGISTER = spreg;

	context.FAST_CALL_ARG0         = (uintptr_t)hoppla.cx;

	context.FAST_CALL_ARG1         = hoppla.dx;

	if ((status = __ntapi->zw_set_context_thread(

			tparams.hthread,

			&context)))

		return __tt_debug_break_process_fail(

			tparams.hthread,

			status);

	/* at last... */

	if ((status = __ntapi->zw_resume_thread(tparams.hthread,0)))

		return __tt_debug_break_process_fail(

			tparams.hthread,

			status);

	/* yay */

	*hthread        = tparams.hthread;

	cid->thread_id  = tparams.cid.thread_id;

	cid->process_id = tparams.cid.process_id;

	return NT_STATUS_SUCCESS;

}