[Toybox] [Nommu] Week ending June 27ish.

[Roy Tam]

Hi all,

2015-06-30 6:55 GMT+08:00 Isaac Dunham <ibid.ag at gmail.com>:
> On Sun, Jun 28, 2015 at 10:57:00PM -0400, Rich Felker wrote:
>> On Sun, Jun 28, 2015 at 06:15:26PM -0500, Rob Landley wrote:
>> > > Are there perhaps any other shells that work on nommu? It would be
>> > > nice to be able to put off toysh until you have time to do a really
>> > > good job on it rather than rushing it because there's nothing else you
>> > > can use...
>> >
>> > Eh, I can do it in stages. And setting up another shell is effort (and
>> > natural test/use cases) that's _not_ going into toysh development, so
>> > I'd rather do it right than do other things that get thrown away.
>> >
>> > That said, sure, http://www.cod5.org/archive/ links to es and pdksh for
>> > example, and uclibc had like 5 of them (all kinda crappy if I recall).
>> > None really an improvement on hush in terms of actually building stuff.
>>
>> I'm pretty sure pdksh conforms to POSIX (at least the 1992 version) so
>> it's probably sufficient for running portable scripts including all
>> configure scripts. I know your goal is much higher (bash
>> compatibility) but it sounds like pdksh could get you a working
>> environment until you finish toysh, with little or no effort spent on
>> the temporary solution.
>
> Some comments:
> - pdksh is a lot closer to bash compatability than "conforms to the 1992
> edition of POSIX" would imply.
> This is partly because bash copied many of its feaures from ksh.
>
> - there *are* configure scripts that need bash--I don't remember the
> software, but I have run into them. Of course, I've also seen configure
> scripts that used ed and software that required the old csh (the one
> that got "&&" and "||" backwards) to build.
> I never looked into exactly what was required, though: I just rm'd
> anything like that.
> configure scripts used to be portable, but nowdays they often just try.
>
> - pdksh works almost everywhere, but this is portability the hard way:
> there are special cases for every *nix of the time, as well as *every*
> other OS (yes, DOS and EMX support included...and probably VMS as well).
> And the code is every bit as ugly as one would infer from that, and
> quite possibly more so.
>
> So theoretically, there probably is a code path that works with nommu.
> But it will almost certainly be nontrivial to even identify it, let
> alone get nommu properly detected and support automatically built.
>
> - OpenBSD ships a version of ksh that has been minimally altered as
> their /bin/sh; this is the basis for loksh. It has been modified
> only minimally.
>
> I think it's entirely sensible for Rob to not poke at pdksh; getting it
> to work right on all Aboriginal's platforms is likely to be a large
> drain. If someone else wants to fix it up and patch Aboriginal until
> they can pass the smoketests on all platforms, accepting their patch
> to use pdksh in Aboriginal might be sensible; but before that, it's
> too big a project for a temporary gain.
>

Regarding pdksh, IIRC it uses fork() for subshells (just like mksh).
I wonder how can it work in NoMMU environment.

>
> Thanks,
> Isaac Dunham
>
>
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