/*++
 
 Copyright (c) 2001-2002 Microsoft Corporation
 
 Module Name:
 
    DuplicateHandleFix.cpp
 
 Abstract:
 
    DuplicateHandle was changed to always NULL the destination handle, even if 
    errors were generated.  THis shim ensures that the DestinationHandle is 
    not modified if the duplication was not successful.
 
 History:
 
    10/11/2001  robkenny        Created.
    02/20/2002  mnikkel         Added check for null lpTargetHandle
 
--*/
 
#include "precomp.h"
 
IMPLEMENT_SHIM_BEGIN(DuplicateHandleFix)
#include "ShimHookMacro.h"
 
APIHOOK_ENUM_BEGIN
    APIHOOK_ENUM_ENTRY(DuplicateHandle)
APIHOOK_ENUM_END
 
typedef BOOL (WINAPI *_pfn_DuplicateHandle)(HANDLE hSourceProcessHandle, HANDLE hSourceHandle, HANDLE hTargetProcessHandle, LPHANDLE lpTargetHandle, DWORD dwDesiredAccess, BOOL bInheritHandle, DWORD dwOptions );
 
/*++
 
 Don't allow DestinationHandle to change of DuplicateHandle generates an error.
 
--*/
 
BOOL
APIHOOK(DuplicateHandle)(
    HANDLE hSourceProcessHandle,  // handle to source process
    HANDLE hSourceHandle,         // handle to duplicate
    HANDLE hTargetProcessHandle,  // handle to target process
    LPHANDLE lpTargetHandle,      // duplicate handle
    DWORD dwDesiredAccess,        // requested access
    BOOL bInheritHandle,          // handle inheritance option
    DWORD dwOptions               // optional actions
    )
{
    HANDLE origHandle = NULL;
 
    // Save the original value
    if (lpTargetHandle)
    {
        origHandle = *lpTargetHandle;
    }
 
    BOOL bSuccess = ORIGINAL_API(DuplicateHandle)(hSourceProcessHandle, 
        hSourceHandle, hTargetProcessHandle, lpTargetHandle, dwDesiredAccess,
        bInheritHandle, dwOptions);
 
    if (!bSuccess && lpTargetHandle)
    {
        //
        // DuplicateHandle has set *lpTargetHandle to NULL, revert to it's previous value.
        //
        *lpTargetHandle = origHandle;
 
        LOGN(eDbgLevelError, "DuplicateHandle failed, reverting *lpTargetHandle to previous value");
    }
 
    return bSuccess;
}
 
/*++
 
 Register hooked functions
 
--*/
 
HOOK_BEGIN
    APIHOOK_ENTRY(KERNEL32.DLL, DuplicateHandle)
HOOK_END
 
IMPLEMENT_SHIM_END