Re: Solaris dldump

[Pip Cet]

"Eli Zaretskii" <eliz@gnu.org> writes:

>> Date: Mon, 19 Aug 2024 12:10:19 +0000
>> From: Pip Cet <pipcet@protonmail.com>
>> Cc: Stefan Kangas <stefankangas@gmail.com>, ali_gnu2@emvision.com,
>>  emacs-devel@gnu.org
>>
>> "Po Lu" <luangruo@yahoo.com> writes:
>> > Pip Cet <pipcet@protonmail.com> writes:
>> >> Wait, I'm not sure I understand that part.  How does removing pure space
>> >> burden anyone with additional labor, hypothetical or not?
>> >
>> > Isn't this theoretical burden the reason that pure space is not to be
>> > removed except along with unexec?
>>
>> Maybe a compromise would be to keep unexec but put it on probation,
>> promising to remove it if problems arise that cannot be convincingly and
>> immediately fixed?
>
> That'd just add to code churn and maintenance burden.  So I prefer
> removing it to begin with.

I've just gone through configure.ac removing all the code that depends
on unexec (no doubt I've missed some), and I must say I now agree it is
time for unexec to go.  In particular, it had so far escaped my
attention that it's incompatible with native compilation!

So I'll update the scratch/no-purespace branch to also remove unexec,
and of course I'm offering to help anyone who wants to fix the remaining
non-pdumper ports.

And while I am skeptical of the value of ASLR, it wuold be really
embarrassing to run into a security issue that's exploitable only
because Emacs disables ASLR for unexec builds.

>> > Anyway, I want pure space gone as much as any of us, I just don't agree
>> > that taking unexec down with it is justified.  Maybe the ELF, XCOFF, and
>> > Windows unexecs, but not the Solaris or DOS ones.
>>
>> DOS in particular is what triggered my question: given the limitations
>> of DOS systems, it's quite possible temacs-as-emacs just wouldn't fly on
>> those machines.
>
> Those limitations are not relevant in our case.

I think it's relevant whether DOS will become completely unusable or
merely difficult to use once unexec is removed, and what can be done to
fix it.

Does the DOS port work on free DOS clones?  And is there a way to gain
access to a Solaris machine to fix pdumper on it?

Pip