Хуки

// DllMain.c
#include <windows.h>
 
extern int SystemHookCoreInit( HINSTANCE hinstDLL );
 
BOOL APIENTRY DllMain(HINSTANCE hinstDLL, DWORD reason, LPVOID lpReserved)
{
     switch (reason)
     {
     case DLL_PROCESS_ATTACH:
      SystemHookCoreInit(hinstDLL);
      break;
      
     case DLL_THREAD_ATTACH:
      break;
      
     case DLL_THREAD_DETACH:
      break;
      
     case DLL_PROCESS_DETACH:
      break;
      
     default:
      OutputDebugString("DllMain: Not sure what happened.\n");
      break;
     }
     
     return TRUE;
}

// SystemHookCore.c
#include <windows.h>
#include <stdio.h>
#include "SystemHookCore.h"
 
HINSTANCE g_appInstance = NULL;
HHOOK hookKeyboard;
 
// prototypes
LRESULT CALLBACK InternalKeyboardHookCallback( int code, WPARAM wparam, LPARAM lparam );
void debug( char* msg );
 
/* ------------------------------------------------------------ */
// initializing dll
int SystemHookCoreInit( HINSTANCE hinstDLL )
{
     debug( "SystemHookCoreInit .. \n" );
 
     if ( g_appInstance == NULL ) {
        g_appInstance = hinstDLL;
     }
     return 0;
}
 
/* ------------------------------------------------------------ */
LRESULT CALLBACK InternalKeyboardHookCallback( int code, WPARAM wparam, LPARAM lparam )
{
     debug( "InternalKeyboardHookCallback called .. \n" );
     return CallNextHookEx( hookKeyboard, code, wparam, lparam );
}
 
/* ------------------------------------------------------------ */
DllExport int InitializeHook( UINT hookID, int threadID )
{
     if ( hookID == WH_KEYBOARD_LL ) {    
        hookKeyboard = SetWindowsHookEx( hookID, (HOOKPROC)InternalKeyboardHookCallback, g_appInstance, threadID );
        debug( "hook initialized\n" );
        return hookKeyboard != NULL;
     }     
     return FALSE;
}
/* ------------------------------------------------------------ */
// utils:
void debug( char* msg )
{
     FILE * pFile;
     pFile = fopen ("d:\\temp.txt","a");
     if ( pFile != NULL ) {
        fputs ( msg, pFile );
        fclose ( pFile );
     }
     printf( msg );
}

// SystemHookCore.h
 
#pragma once
 
#define DllExport   __declspec( dllexport ) 
 
#define KEYBOARDH WH_KEYBOARD_LL
 
typedef LRESULT (CALLBACK *HookProc)( int code, WPARAM hookId, LPARAM l );
 
int SystemHookCoreInit();
 
/* user API */
DllExport int   InitializeHook      ( UINT hookID, int threadID );

// test/main.c
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "SystemHookCore.h"
 
const int ALL_THREADS = 0;
 
int main() 
{
    InitializeHook( WH_KEYBOARD_LL, ALL_THREADS);
  
    system("pause");
  
    return 0;
}

// test/SystemHookCore.h
 
#pragma once
 
#define DllImport   __declspec( dllimport ) 
 
#define KEYBOARDH WH_KEYBOARD_LL
 
typedef LRESULT (CALLBACK *HookProc)( int code, WPARAM hookId, LPARAM l );
 
enum hook_errors {
     HSUCCESS = 0,
     HARGUMENT_ERROR,
     HALREADY_SET,
     HNOT_IMPLEMENTED_YET
};
 
/* user API */
DllImport int   InitializeHook      ( UINT hookID, int threadID );