Re: File sealing

Hi,

On Thursday, November 1, 2018 6:25 PM, Ted Unangst <tedu@tedunangst.com> wrote:
> Simon Ser wrote:
>
> > Hi all> I'd like to know if there are plans to add a feature similar to file
> > sealing [2] in OpenBSD.
>
> I don't think so. You explained a possible use, but didn't actually explain if
> code using file sealing already exists.

Thanks for your reply. Indeed, code using file sealing exists, for instance
GTK+ [1] and GLFW [2].

I've been told that for this same use-case, another mechanism has already been
implemented on OpenBSD. It's an additional parameter that can be passed to mmap
and makes truncated regions appear as zeros instead of triggering SIGBUS. However
I couldn't find any more info about this. Can you tell me more about this?

Thanks,

Simon Ser

[1]: https://gitlab.gnome.org/GNOME/gtk/blob/master/gdk/wayland/gdkdisplay-wayland.c#L1223
[2]: https://github.com/glfw/glfw/blob/master/src/wl_window.c#L156