From 2a7f67d71f9d34c49de6a81e7deab10882bf930f Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Tue, 28 May 2019 17:46:28 +0000
Subject: debug helpers: __ntapi_tt_debug_break_process(): initial
 implementation.

---
 src/debug/ntapi_tt_debug_break_process.c | 126 +++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 src/debug/ntapi_tt_debug_break_process.c

(limited to 'src/debug')

diff --git a/src/debug/ntapi_tt_debug_break_process.c b/src/debug/ntapi_tt_debug_break_process.c
new file mode 100644
index 0000000..3ad0daf
--- /dev/null
+++ b/src/debug/ntapi_tt_debug_break_process.c
@@ -0,0 +1,126 @@
+/********************************************************/
+/*  ntapi: Native API core library                      */
+/*  Copyright (C) 2013--2019  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			(*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;
+}
-- 
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