Hi Ludo,

On Tue,  4 Jun 2019 23:01:15 +0200
Ludovic Courtès <ludo@gnu.org> wrote:
> +                   ,@(if entry-point
> +                         `(;; This one if for Singularity 2.x.
> +                           "-p"
> +                           ,(string-append
> +                             "/.singularity.d/actions/run s 777 0 0 "
> +                             (relative-file-name "/.singularity.d/actions"
> +                                                 (string-append #$profile "/"
> +                                                                entry-point)))
> +
> +                           ;; This one is for Singularity 3.x.
> +                           "-p"
> +                           ,(string-append
> +                             "/.singularity.d/runscript s 777 0 0 "
> +                             (relative-file-name "/.singularity.d"
> +                                                 (string-append #$profile "/"
> +                                                                entry-point))))

Hmm, 777 (anyone can write)?  It it necessary?

Also, in general, do we conflate "squashfs" and "singularity"?  It has been
that way in guix/scripts/pack.scm's squashfs-image before this patch already
and a few extra files can't hurt, but we could also just provide a
function "singularity-image" or something.

LGTM!