Re: The Case for Rust (in the base system)

Warner Losh wrote in
 <CANCZdfpB9k_gzuLUij-kuwXMeMDqVwfx9DUsWBdmwNEtMvVkaA@mail.gmail.com>:
 |On Mon, Aug 5, 2024 at 4:06 PM Poul-Henning Kamp <phk@phk.freebsd.dk> \
 |wrote:
 |> --------
 |> Warner Losh writes:
 |>>>> Most user space tools could be written in lua.
 |>>>
 |>>> That /exact/ same argument was made for Perl :-)
 |>>
 |>> Lua's been in the base since I imported it for the boot loader, \
 |>> though...
 |>
 |> Lua is is much more "language" than "eco-system", by design as I
 |> understand it, so that is a different situation than Perl or Rust.
 |
 |Indeed. The standard stuff is fairly small, and we're doing it all as
 |a 'private' library, so ports will never see what we pull in.
 |
 |I personally do not subscribe to to the "let's rewrite all the 50
 |> year old source code to make it more safe" philosophy, but there
 |> are valid arguments when the old code is horrible.
 |
 |Plus we're writing new stuff only, and typically only where it makes
 |a lot of sense (lots of string processing). Plus we're keeping the scripts
 |as compatible with what little ecosystem there is so we can go back
 |and forth between the ports lua and the base flua.
 |
 |> But there are some wrinkles.
 |>
 |> First: Anything setuid/setgid is off-limits.
 |>
 |> There are good reasons why we dont have setuid shell-scripts (any more!)
 |>
 |> I guess with most systems being effectively single-user these days,
 |> that may not be as much a security focus as it was back in the 1990ies.
 |
 |Yea. No plans there.
 |
 |> Second: Performance.
 |>
 |> I cannot remember the exact subset of bin programs somebody did in
 |> Perl as proof of concept, but it slowed down buildworld a LOT to
 |> fire up all of Perl to do trivial stuff like "echo", "chown" and
 |> "mkdir".
 |>
 |> Lua may be cheaper than Perl, but it will still be measurable.
 |
 |Yea. I'm guessing you wouldn't notice, but why do that. There's
 |no benefit and only a myriad of ways to introduce new bugs
 |or non-posix conformance where we were conformant before.
 |
 |I'm definitely in the "why are we rewriting stuff in rust" because
 |it doesn't move the ball forward, really. At best it's a great leap
 |sideways,
 |maybe with marginally better actual safety. At worst, it's a great \
 |leap into
 |a morass of almost compatible that causes great grief in the gaps, or
 |worse, has new security problems the old one didn't. So rewriting
 |for the sake of rewriting seems like a giant waste of resources.
 |Rewriting strategically to fix areas that have had safey issues
 |may be different, but cp.rst isn't going to be any better, than
 |cp.c in most aspects because cp.c has had 50 years to be
 |debugged.  And 50 years makes up for a lot of danger
 |in the language.... So there may be things that we get some
 |advantage out of by doing a rewrite in rust, but I'm in the
 |'case by case basis' camp there: those cases where the cost / benefit
 |ratio is favorable should be considered. But they can't be
 |considered entirely in a vacuum because there's a non-zero
 |cost to rust in the base, even as an external toolchain.

That sounds nothing but good.
(I was not really serious at first btw.)  

 |Having said all that, I'd love to see us be able to make better of rust and
 |new rust programs where it makes sense. That's why I've been
 |encouraging people to give it a go to show us the money. To
 |show up that we can integrate it (even if it is just a few lines in
 |Makefile.inc1 that builds everything, optionally, as part of
 |buildworld). That shows us we can keep the dependency hell
 |under control, that we can update things sanely (more ecosystem
 |here, not language). How much work is it to track the latest versions,
 |how do we deal with that as the number of new rust programs grow,
 |how do we deal with ABI stability, etc. And to show us if there's an
 |actual advantage to all of that over what we can do in ports, or what
 |we might do with pkgbase somehow. I'm unsure of the outcome of all
 |this, but I think it would be wrong to shout it down completely. To do
 |all that, people need room to experiment and show what's what.

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)
|
| Only during dog days:
| On the 81st anniversary of the Goebbel's Sportpalast speech
| von der Leyen gave an overlong hypocritical inauguration one.
| The brew's essence of our civilizing advancement seems o be:
|   Total war - shortest war -> Permanent war - everlasting war