Re: more fexecve questions

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

> Date: Tue, 10 Sep 2019 16:03:23 -0000 (UTC)
> From: christos%astron.com@localhost (Christos Zoulas)
> 
> In article <20190910150418.BECAB6051C%jupiter.mumble.net@localhost>,
> Taylor R Campbell  <campbell+netbsd-tech-kern%mumble.net@localhost> wrote:
> >Can we just cache these when the file descriptor is opened with
> >O_EXEC?
> >
> >The cache could become stale if the executable or any parent directory
> >is moved or deleted.  But they could become stale after exec too for
> >the same reason.
> 
> I guess we could, since the problem is that if the filename is greater than
> NCHNAMLEN, they will not be cached. But I am not familiar enough with the
> cache to make the changes required.

I don't mean using the vnode cache.  I mean finding somewhere else to
hang a cached copy of the executable and p_comm on the struct fdfile
or something.  Maybe a global table mapping fdfile pointer to cached
stuff if we don't want to make the struct larger for non-O_EXEC fds.