From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH] build: container: Use the same clone flags as fork(3).
Date: Mon, 07 Sep 2015 18:13:16 +0200
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	(David Thompson's message of "Sat, 05 Sep 2015 14:19:08 -0400")
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To: David Thompson <dthompson2@worcester.edu>
Cc: guix-devel@gnu.org

David Thompson <dthompson2@worcester.edu> skribis:

> This patch resolves an issue I was having when working with containers
> at the REPL, which means it probably presented undetected issues
> elsewhere.

Calling =E2=80=98primitive-fork=E2=80=99 at the REPL is not very useful any=
way since you
end up with two Guiles trying to read from the same tty.

> From 61ebbe55f7f6d4d4eb42db957d6fc7b4eaf282a6 Mon Sep 17 00:00:00 2001
> From: David Thompson <dthompson2@worcester.edu>
> Date: Sat, 5 Sep 2015 14:10:08 -0400
> Subject: [PATCH] build: container: Use the same clone flags as fork(3).
>
> The intent is to make 'clone' behave a lot more like 'primitive-fork', wh=
ich
> calls clone(2) with SIGCHLD, CLONE_CHILD_CLEARTID, and CLONE_CHILD_SETTID
> flags.  Notably, running 'clone' at the REPL without these flags would br=
eak
> the REPL beyond repair.
>
> * guix/build/syscalls.scm (CLONE_CHILD_CLEARTID, CLONE_CHILD_SETTID): New
>   variables.
> * gnu/build/linux-container.scm (namespaces->bit-mask): Add
>   CLONE_CHILD_CLEARTID and CLONE_CHILD_SETTID to bit mask.

Looking at clone(2) and libc, I=E2=80=99m guessing that without these flags=
, the
child would have a wrong idea of its thread ID, which in turn may cause
all sorts of problems, right?

LGTM.

Thanks,
Ludo=E2=80=99.