blob: 4dffe047d6630013a41855e22532f60c811fcc9d [file] [log] [blame]
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stdio.h>
#include <windows.h>
#include "hooking_dll.h"
// This data section creates a common area that is accessible
// to all instances of the DLL (in every process). They map to
// the same physical memory location.
// **Note that each instance of this DLL runs in the context of
// the process it's injected into, so things like pointers and
// addresses won't work.
// **Note that any variables must be initialized to put them in
// the specified segment, otherwise they will end up in the
// default data segment.
#pragma data_seg(".hook")
HHOOK hook = NULL;
bool hook_called = false;
#pragma data_seg()
#pragma comment(linker, "/SECTION:.hook,RWS")
namespace {
HANDLE event = NULL;
namespace hooking_dll {
void SetHook(HHOOK hook_handle) {
hook = hook_handle;
bool WasHookCalled() {
return hook_called;
LRESULT HookProc(int code, WPARAM w_param, LPARAM l_param) {
hook_called = true;
if (event)
// Recent versions of Windows do not require the HHOOK to be passed along,
// but I'm doing it here to show the shared use of the HHOOK variable in
// the shared data segment. It is set by the instance of the DLL in the
// main test process.
return CallNextHookEx(hook, code, w_param, l_param);
} // namespace hooking_dll
BOOL WINAPI DllMain(HINSTANCE instance, DWORD reason, LPVOID reserved) {
if (reason == DLL_PROCESS_ATTACH) {
// The testing process should have set up this named event already
// (if the test needs this event to be signaled).
event = ::OpenEventW(EVENT_MODIFY_STATE, FALSE, hooking_dll::g_hook_event);
if (reason == DLL_PROCESS_DETACH && event != nullptr)
return TRUE;