From: Eelco Dolstra <eelco.dolstra@logicblox.com>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: guix-devel <guix-devel@gnu.org>, nix-dev <nix-dev@lists.science.uu.nl>
Subject: Re: Avoiding threads in the daemon
Date: Fri, 19 Dec 2014 19:20:42 +0100 [thread overview]
Message-ID: <54946C7A.9020804@logicblox.com> (raw)
In-Reply-To: <87mw6lym95.fsf@gnu.org>
Hi,
On 18/12/14 17:32, Ludovic Courtès wrote:
> Thus, I think Nix commit 49fe95 (which introduces monitor-fd.hh, which
> uses std::thread just for convenience) should be reverted, along with
> the subsequent commits to that file; then commit 524f89 can be reverted.
I really don't want to get rid of threads because they're useful and I want to
use them more in the future (e.g. build.cc would be much simpler if it used
threads rather than the current event-driven approach; nix-daemon could handle
client connections with a thread rather than a process; etc.).
I see a few ways to get PID namespaces back:
* Do a regular fork followed by clone(... | CLONE_NEWPID | CLONE_PARENT) (after
which the intermediate process can exit).
* Call setuid/setgid via syscall() to bypass the locking in the Glibc wrappers.
However, there might be other problematic functions so this is not a great solution.
* Get the Glibc folks to provide a way to run at-fork handlers with clone().
Clearly the first option is the easiest.
--
Eelco Dolstra | LogicBlox, Inc. | http://nixos.org/~eelco/
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next prev parent reply other threads:[~2014-12-19 18:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-18 16:32 Avoiding threads in the daemon Ludovic Courtès
2014-12-19 18:20 ` Eelco Dolstra [this message]
2014-12-19 18:41 ` Shea Levy
2014-12-19 18:46 ` Eelco Dolstra
2014-12-19 21:31 ` Ludovic Courtès
2014-12-19 21:36 ` Luca Bruno
2014-12-20 0:11 ` Alexander Kjeldaas
2014-12-23 16:26 ` Eelco Dolstra
2014-12-26 22:02 ` Ludovic Courtès
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