//?頭文件
//?ApiHook.h:?interface?for?the?CApiHook?class.
//
//////////////////////////////////////////////////////////////////////

 #ifndef? API_HOOK_H
 #define? API_HOOK_H

 class? CApiHook?
 {
 public :
???? HANDLE?hProc ;
???? Unlock ();
???? Lock ();
???? BOOL?Initialize ( LPCTSTR?lpLibFileName ,? LPCTSTR?lpProcName ,? FARPROC?lpNewFunc );
???? void? SetHookOn ( void );
???? void? SetHookOff ( void );
???? CApiHook ();
???? virtual? ~ CApiHook ();

 protected :
???? BYTE?m_OldFunc [ 8 ];
???? BYTE?m_NewFunc [ 8 ];
???? FARPROC?m_lpHookFunc ;
???? CRITICAL_SECTION?m_cs ;
};

 #endif

 //?實現文件
//?ApiHook.cpp:?implementation?of?the?CApiHook?class.
//
//////////////////////////////////////////////////////////////////////

 #include? "stdafx.h"
 #include? "ApiHook.h"
 #include? < stdio . h >

 //////////////////////////////////////////////////////////////////////
//?Construction/Destruction
//////////////////////////////////////////////////////////////////////

 #define? OPEN_FLAGS? (? PROCESS_VM_OPERATION? |? PROCESS_VM_READ? |? PROCESS_VM_WRITE? )

 CApiHook :: CApiHook ()
{
???? InitializeCriticalSection (& m_cs );
}

 CApiHook ::~ CApiHook ()
{
???? CloseHandle ( hProc );
???? DeleteCriticalSection (& m_cs );
}

 void? CApiHook :: SetHookOn ( void )
{
???? DWORD?dwOldFlag ;

???? if ( WriteProcessMemory ( hProc , m_lpHookFunc , m_NewFunc , 5 , 0 ))
????{
???????? return ;
????}

???? MessageBox ( NULL , "SetHookOn" , "fail" , MB_OK );
???? return ;
}

 void? CApiHook :: SetHookOff ( void )
{
???? DWORD?dwOldFlag ;

???? if ( WriteProcessMemory ( hProc , m_lpHookFunc , m_OldFunc , 5 , 0 ))
????{
???????? return ;
????}
???? MessageBox ( NULL , "SetHookOff" , "fail" , MB_OK );
???? return ;
}

 BOOL?CApiHook :: Initialize ( LPCTSTR?lpLibFileName ,? LPCTSTR?lpProcName ,? FARPROC?lpNewFunc )
{
???? HMODULE?hModule ;

???? hModule = LoadLibrary ( lpLibFileName );
???? if ( NULL == hModule )
???????? return? FALSE ;

???? m_lpHookFunc = GetProcAddress ( hModule , lpProcName );
???? if ( NULL == m_lpHookFunc )
???????? return? FALSE ;

???? DWORD?dwProcessID = GetCurrentProcessId ();
???? DWORD?dwOldFlag ;
???? hProc = GetCurrentProcess ( /*OPEN_FLAGS,0,dwProcessID*/ );

???? if ( hProc == NULL )
????{
???????? MessageBox ( NULL , "Initialize.OpenProcess" , "fail" , MB_OK );
???????? return? FALSE ;
????}

???? if ( ReadProcessMemory ( hProc , m_lpHookFunc , m_OldFunc , 5 , 0 ))
????{
???????? m_NewFunc [ 0 ]= 0xe9 ;
???????? DWORD * pNewFuncAddress ;
???????? pNewFuncAddress =( DWORD *)& m_NewFunc [ 1 ];
????????* pNewFuncAddress =( DWORD ) lpNewFunc -( DWORD ) m_lpHookFunc - 5 ;

???????? return? TRUE ;
????}

???? MessageBox ( NULL , "Initialize" , "fail" , MB_OK );
???? return? FALSE ;
}

 CApiHook :: Lock ()
{
???? EnterCriticalSection (& m_cs );
}

 CApiHook :: Unlock ()
{
???? LeaveCriticalSection (& m_cs );
}