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1;;; GNU Guix --- Functional package management for GNU
2;;; Copyright © 2015 David Thompson <[email protected]>
3;;; Copyright © 2016, 2017 Ludovic Courtès <[email protected]>
4;;;
5;;; This file is part of GNU Guix.
6;;;
7;;; GNU Guix is free software; you can redistribute it and/or modify it
8;;; under the terms of the GNU General Public License as published by
9;;; the Free Software Foundation; either version 3 of the License, or (at
10;;; your option) any later version.
11;;;
12;;; GNU Guix is distributed in the hope that it will be useful, but
13;;; WITHOUT ANY WARRANTY; without even the implied warranty of
14;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15;;; GNU General Public License for more details.
16;;;
17;;; You should have received a copy of the GNU General Public License
18;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
19
20(define-module (gnu system linux-container)
21 #:use-module (ice-9 match)
22 #:use-module (srfi srfi-1)
23 #:use-module (guix config)
24 #:use-module (guix store)
25 #:use-module (guix gexp)
26 #:use-module (guix derivations)
27 #:use-module (guix monads)
28 #:use-module (guix modules)
29 #:use-module (gnu build linux-container)
30 #:use-module (gnu services)
31 #:use-module (gnu system)
32 #:use-module (gnu system file-systems)
33 #:export (system-container
34 containerized-operating-system
35 container-script))
36
37(define (containerized-operating-system os mappings)
38 "Return an operating system based on OS for use in a Linux container
39environment. MAPPINGS is a list of <file-system-mapping> to realize in the
40containerized OS."
41 (define user-file-systems
42 (remove (lambda (fs)
43 (let ((target (file-system-mount-point fs))
44 (source (file-system-device fs)))
45 (or (string=? target (%store-prefix))
46 (string=? target "/")
47 (and (string? source)
48 (string-prefix? "/dev/" source))
49 (string-prefix? "/dev" target)
50 (string-prefix? "/sys" target))))
51 (operating-system-file-systems os)))
52
53 (define (mapping->fs fs)
54 (file-system (inherit (file-system-mapping->bind-mount fs))
55 (needed-for-boot? #t)))
56
57 (operating-system (inherit os)
58 (swap-devices '()) ; disable swap
59 (file-systems (append (map mapping->fs (cons %store-mapping mappings))
60 %container-file-systems
61 user-file-systems))))
62
63(define* (container-script os #:key (mappings '()))
64 "Return a derivation of a script that runs OS as a Linux container.
65MAPPINGS is a list of <file-system> objects that specify the files/directories
66that will be shared with the host system."
67 (let* ((os (containerized-operating-system os mappings))
68 (file-systems (filter file-system-needed-for-boot?
69 (operating-system-file-systems os)))
70 (specs (map file-system->spec file-systems)))
71
72 (mlet* %store-monad ((os-drv (operating-system-derivation
73 os
74 #:container? #t)))
75
76 (define script
77 (with-imported-modules (source-module-closure
78 '((guix build utils)
79 (gnu build linux-container)))
80 #~(begin
81 (use-modules (gnu build linux-container)
82 (gnu system file-systems) ;spec->file-system
83 (guix build utils))
84
85 (call-with-container (map spec->file-system '#$specs)
86 (lambda ()
87 (setenv "HOME" "/root")
88 (setenv "TMPDIR" "/tmp")
89 (setenv "GUIX_NEW_SYSTEM" #$os-drv)
90 (for-each mkdir-p '("/run" "/bin" "/etc" "/home" "/var"))
91 (primitive-load (string-append #$os-drv "/boot")))
92 ;; A range of 65536 uid/gids is used to cover 16 bits worth of
93 ;; users and groups, which is sufficient for most cases.
94 ;;
95 ;; See: http://www.freedesktop.org/software/systemd/man/systemd-nspawn.html#--private-users=
96 #:host-uids 65536))))
97
98 (gexp->script "run-container" script))))