From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([209.51.188.92]:38225)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1h4WmN-0006xh-4H
	for guix-patches@gnu.org; Thu, 14 Mar 2019 16:16:39 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1h4WXI-0008EO-30
	for guix-patches@gnu.org; Thu, 14 Mar 2019 16:01:08 -0400
Received: from debbugs.gnu.org ([209.51.188.43]:58779)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <Debian-debbugs@debbugs.gnu.org>)
	id 1h4WXH-0008Da-0F
	for guix-patches@gnu.org; Thu, 14 Mar 2019 16:01:03 -0400
Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2)
	(envelope-from <Debian-debbugs@debbugs.gnu.org>) id 1h4WXG-00007G-S8
	for guix-patches@gnu.org; Thu, 14 Mar 2019 16:01:02 -0400
Subject: [bug#34638] [PATCH 2/4] linux-container: Add
	'start-child-in-container'.
Resent-Message-ID: <handler.34638.B34638.1552593618359@debbugs.gnu.org>
From: Ludovic =?UTF-8?Q?Court=C3=A8s?= <ludo@gnu.org>
References: <20190224161855.2632-1-mail@cbaines.net>
	<20190224161855.2632-2-mail@cbaines.net>
Date: Thu, 14 Mar 2019 19:17:43 +0100
In-Reply-To: <20190224161855.2632-2-mail@cbaines.net> (Christopher Baines's
	message of "Sun, 24 Feb 2019 16:18:53 +0000")
Message-ID: <87lg1hiam0.fsf@gnu.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
List-Id: <guix-patches.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/guix-patches>,
	<mailto:guix-patches-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/guix-patches/>
List-Post: <mailto:guix-patches@gnu.org>
List-Help: <mailto:guix-patches-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/guix-patches>,
	<mailto:guix-patches-request@gnu.org?subject=subscribe>
Errors-To: guix-patches-bounces+kyle=kyleam.com@gnu.org
Sender: "Guix-patches" <guix-patches-bounces+kyle=kyleam.com@gnu.org>
To: Christopher Baines <mail@cbaines.net>
Cc: 34638@debbugs.gnu.org

Hello!

Christopher Baines <mail@cbaines.net> skribis:

> This new procedure is similar to open-pipe* in (ice-9 popen), but using
> run-container from (gnu build linux-container).
>
> * gnu/build/linux-container.scm (start-child-in-container): New procedure.

[...]

 +(define* (start-child-in-container command
> +                                   #:key read? write?
> +                                   (root 'temporary)
> +                                   (mounts '())
> +                                   (namespaces %namespaces)
> +                                   (host-uids 1)
> +                                   (extra-environment-variables '()))

We could even call that =E2=80=98open-pipe/container=E2=80=99, for clarity.

> +  (define (with-root-directory f)
> +    (if (eq? root 'temporary)
> +        (call-with-temporary-directory f)
> +        (f root)))
> +
> +  ;; (ice-9 popen) internals
> +  (define make-rw-port (@@ (ice-9 popen) make-rw-port))
> +  (define pipe-guardian (@@ (ice-9 popen) pipe-guardian))
> +  (define make-pipe-info (@@ (ice-9 popen) make-pipe-info))

So this is the funky part.  ;-)

What if we did something like:

  (call-with-container mounts
    (lambda ()
      ;; Somehow act as a proxy between the output process
      ;; and the one spawned by =E2=80=98open-pipe*=E2=80=99.
      (open-pipe* =E2=80=A6)))

?  Would that work?

That=E2=80=99s create an extra process, but if it works, it=E2=80=99s proba=
bly safer and
a lesser maintenance burden.

Now, I think that Guile should expose some of the popen internals
somehow so we can do things like you did, but that=E2=80=99s another story.

Ludo=E2=80=99.