From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludovic.courtes@inria.fr (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Generating wrappers for execution in non-root non-Guix contexts
Date: Thu, 26 Apr 2018 16:58:59 +0200
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References: <87zi1rwsv6.fsf@inria.fr> <87fu3it7cm.fsf@elephly.net>
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In-Reply-To: <87fu3it7cm.fsf@elephly.net> (Ricardo Wurmus's message of "Thu,
	26 Apr 2018 15:39:21 +0200")
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To: Ricardo Wurmus <rekado@elephly.net>
Cc: guix-devel <guix-devel@gnu.org>

Hey!

Ricardo Wurmus <rekado@elephly.net> skribis:

>> We could also have wrappers fall back to PRoot when unshare(2) fails.
>
> Good idea.  Could we use ptrace directly and optimize it for the case of
> =E2=80=9C/gnu/store=E2=80=9D paths?  I=E2=80=99m just guessing that PRoot=
 may incur a higher
> performance penalty because it=E2=80=99s so generic compared to a compile=
-time
> deterministic use of ptrace =E2=80=93 after all, we know all /gnu/store
> locations in advance.

IWBN, but that=E2=80=99s a project in its own.  ptrace(2) requires knowledge
about the architecture=E2=80=99s ABI so that you know what registers to loo=
k at
when a syscall happens, and so on.  So for now it=E2=80=99ll have to be PRo=
ot.

I=E2=80=99ll try to come up with a patch set without PRoot support to begin
with.

Thanks for your feedback,
Ludo=E2=80=99.