From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH 08/15] gnu: build: Add Linux container module.
Date: Tue, 07 Jul 2015 15:51:01 +0200
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	(David Thompson's message of "Mon, 6 Jul 2015 09:16:37 -0400")
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To: David Thompson <dthompson2@worcester.edu>
Cc: guix-devel@gnu.org, David Thompson <davet@gnu.org>

David Thompson <dthompson2@worcester.edu> skribis:

> * gnu/build/linux-container.scm: New file.
> * gnu-system.am (GNU_SYSTEM_MODULES): Add it.
> * .dir-locals.el: Add Scheme indent rules for 'call-with-clone', 'with-cl=
one',
>   'call-with-container', and 'container-excursion'.
> * tests/containers.scm: New file.
> * Makefile.am (SCM_TESTS): Add it.

[...]

> +(define (mount-flags->bit-mask flags)
> +  "Return the number suitable for the 'flags' argument of 'mount' that
> +corresponds to the symbols listed in FLAGS."
> +  (let loop ((flags flags))
> +    (match flags
> +      (('read-only rest ...)
> +       (logior MS_RDONLY (loop rest)))
> +      (('bind-mount rest ...)
> +       (logior MS_BIND (loop rest)))
> +      (('no-suid rest ...)
> +       (logior MS_NOSUID (loop rest)))
> +      (('no-dev rest ...)
> +       (logior MS_NODEV (loop rest)))
> +      (('no-exec rest ...)
> +       (logior MS_NOEXEC (loop rest)))
> +      (()
> +       0))))
> +
> +(define* (mount-file-system spec root)
> +  "Mount the file system described by SPEC under ROOT.  SPEC must have t=
he
> +form:
> +
> +  (DEVICE TITLE MOUNT-POINT TYPE (FLAGS ...) OPTIONS CHECK?)

Could we share these two procedures with (gnu build file-systems)?

I suspect the problem you encountered is that (gnu build file-systems)
doesn=E2=80=99t use (guix build syscalls), and instead expects the
statically-linked Guile with the guile-syscalls.patch.

To work around that, I think we should shamelessly add something like
this in (gnu build file-system):

  (unless (defined? 'mount)
    (module-use! (current-module)
                 (resolve-interface '(guix build syscalls))))

WDYT?

> +(define (namespaces->bit-mask namespaces)
> +  "Return the number suitable for the 'flags' argument of 'clone' that
> +corresponds to the symbols in NAMESPACES."

I would be in favor of =E2=80=9Cname spaces=E2=80=9D (two words), but maybe=
 that=E2=80=99s
because I=E2=80=99m an old fart, so I won=E2=80=99t insist.

> +(test-assert "call-with-container, pid namespace"
> +  (zero?
> +   (call-with-container '()
> +     (lambda ()
> +       (match (primitive-fork)
> +         (0
> +          ;; The first forked process in the new pid namespace is pid 2.
> +          (assert-exit (=3D 2 (getpid))))

But its parent doesn=E2=80=99t sees itself as PID 1?

Thanks,
Ludo=E2=80=99.