Function execution time Example. (C++)

std::chrono::system_clock::time_point start = std::chrono::system_clock::now();

myFunc();

std::chrono::duration<double> sec = std::chrono::system_clock::now() - start;

std::cout << "The time taken to perform the function myFunc()  : " << sec.count() << " seconds" << std::endl;

Create Thread Class Example (C++)

The class "std :: thread" exists but has been created for fun.

ThreadClass.h

#pragma once

#include <iostream>

#include <windows.h>

class ThreadClass

{

public:

ThreadClass();

~ThreadClass();

void start();

void stop();

bool isRun();

static DWORD __stdcall run_(void* p);

virtual void run() = 0;

protected:

bool threadRunFlag;

HANDLE m_Thread;

};

ThreadClass.cpp

#include "ThreadClass.h"

//

//\brief constructor,

//\param

//\return

//

ThreadClass::ThreadClass()

{

this->threadRunFlag = false;

}

//

//\brief destructor

//\param

//\return

//

ThreadClass::~ThreadClass()

{

if (this->isRun()) {

this->stop();

}

}

//

//\brief  thread start

//\param

//\return

//

void ThreadClass::start()

{

m_Thread = CreateThread(0, 0, run_, (void*)this, 0, 0);

}

///

///\brief thread end

///\param

///\return

///

void ThreadClass::stop()

{

this->threadRunFlag = false;

// to be...

}

//

//\brief thread status

//\param

//\return

//

bool ThreadClass::isRun()

{

return this->threadRunFlag;

}

//

//\brief thread run

//\param

//\return

//

DWORD __stdcall ThreadClass::run_(void * p)

{

ThreadClass* const THISCLASS = static_cast<ThreadClass*>(p);

THISCLASS->threadRunFlag = true;

THISCLASS->run();

return 0;

}

Shared folder permission setting (If you can not access the shared folder)

Problem :

I set up a shared folder in Virtualbox, but I can not access the shared folder.  

Solve :

Installing the VirtualBox Guest Additions  -> Automatically mount shared folders with VirtualBox ("/media /sh_foldername" will be shown) -> Add Ubuntu users to your vboxsf group

$ sudo -s

Input root password

$ usermod -aG vboxsf <youruser>

$ reboot

Qmake error (QT)

Error:

linux Could not determine which "make" command to run. Check the "make" step in the build configuration.

Solve :

$ sudo apt install cmake g++

$ sudo apt remove libgl1-mesa-dev
$ sudo apt install libgl1-mesa-dev

Hooking Example (case 2. class method hooking)

This is an example of hooking a class function.

This article doesn't have many examples of hooking c ++ classes.

The following code:

Class TestClass {

Public:

…

int myPrintf(const std::string & id, const int & value);

…

}

Hook code:

int TestClass::myPrintf(const std::string & id, const int & value) {

    typedef int (TestClass::*HookFunction)(const std::string & id, const int & value);

    static HookFunction orgMethod = 0;

    if (orgMethod == 0) {

        void *tmpPtr = dlsym(RTLD_NEXT, "Mangling Name");

        memcpy(&orgMethod, &tmpPtr, sizeof(void *));

    }

   

    int orgRetValue;

    orgRetValue = (this->*orgMethod)(id, value);

    return orgRetValue;

#C #C++ #Linux #Embedded #Hooking Example #Hooking #Class Hooking

Hooking Example (case 1. getchar() / rand())

 Hooking Example:

 1. Getchar() / rand

   only C , and this code is meaningless code. Only test!

Target code.

- target.c

  : gcc –o target target.c

Hook code.

- hook.c

  : gcc -shared -fPIC -o hook.so main.c –ldl

Exec:

Normal:

$  ./target

Hook:

$LD_PRELOAD="/home/xxxx/hook_test/hook/hook.so" ./target

*the blue box : privacy.

#C #C++ #Linux #Embedded #Hooking Example #Hooking 

API Hooking

• API Hooking

- A technique to intercept API calls to get control

- The most widely used technique with Message hooking

API ?

- An interface to control the functions provided by the operating system or programming language.

- On Windows, use the Win32 API

*As an example of a process, all processes load kernel32.dll and access the system through ntdll.dll.

*Win32 API: Windows OS can't directly use system resources(memory, file, network, video, sound, etc.) by user applications. It is directly managed by the OS.(due to stability, security, efficiency, and so on.)

=> Using the Win32 API (the meaningful program can't be created without API function.)

#C #C++ #Linux #Embedded #Hooking Example #Hooking #API #API Hooking