Re: [PATCH 3/4] include: Define IoSkipCurrentIrpStackLocation

[Sebastian Lackner]

On 12.10.2016 12:31, Aric Stewart wrote:
> Signed-off-by: Aric Stewart
>
> include/ddk/wdm.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> 0003-include-Define-IoSkipCurrentIrpStackLocation.txt
>
> diff --git a/include/ddk/wdm.h b/include/ddk/wdm.h
> index 5602f7d..5671948 100644
> --- a/include/ddk/wdm.h
> +++ b/include/ddk/wdm.h
> @@ -1175,9 +1175,11 @@ NTSTATUS WINAPI ObCloseHandle(IN HANDLE handle);
>  # ifdef NONAMELESSSTRUCT
>  #  define IoGetCurrentIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.s.u2.CurrentStackLocation)
>  #  define IoGetNextIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.s.u2.CurrentStackLocation - 1)
> +#  define IoSkipCurrentIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.s.u2.CurrentStackLocation++); ((_Irp)->CurrentLocation++)
>  # else
>  #  define IoGetCurrentIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.u2.CurrentStackLocation)
>  #  define IoGetNextIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.u2.CurrentStackLocation - 1)
> +#  define IoSkipCurrentIrpStackLocation(_Irp) ((_Irp)->Tail.Overlay.u2.CurrentStackLocation++); ((_Irp)->CurrentLocation++)
>  # endif
>  #else
>  # ifdef NONAMELESSSTRUCT

Is this definition based on a Windows header file? I have only found two versions,
either with a "{ ... }" block or with a static inline function. Your definition
would not work correctly in a situation like this:

if (...) IoSkipCurrentIrpStackLocation(irp);

Which would be expanded to:

if (...) irp->Tail.Overlay.s.u2.CurrentStackLocation++;
irp->CurrentLocation++;

Please note that the second statement is no longer conditional. Also, what about
the two other #ifdef branches directly below?

Regards,
Sebastian