1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
| | ;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (gnu system mapped-devices)
#:use-module (guix gexp)
#:use-module (guix records)
#:use-module (gnu services)
#:use-module (gnu services shepherd)
#:autoload (gnu packages cryptsetup) (cryptsetup)
#:use-module (srfi srfi-1)
#:use-module (ice-9 match)
#:export (mapped-device
mapped-device?
mapped-device-source
mapped-device-target
mapped-device-type
mapped-device-kind
mapped-device-kind?
mapped-device-kind-open
mapped-device-kind-close
device-mapping-service-type
device-mapping-service
luks-device-mapping))
;;; Commentary:
;;;
;;; This module supports "device mapping", a concept implemented by Linux's
;;; device-mapper.
;;;
;;; Code:
(define-record-type* <mapped-device> mapped-device
make-mapped-device
mapped-device?
(source mapped-device-source) ;string
(target mapped-device-target) ;string
(type mapped-device-type)) ;<mapped-device-kind>
(define-record-type* <mapped-device-type> mapped-device-kind
make-mapped-device-kind
mapped-device-kind?
(open mapped-device-kind-open) ;source target -> gexp
(close mapped-device-kind-close ;source target -> gexp
(default (const #~(const #f)))))
\f
;;;
;;; Device mapping as a Shepherd service.
;;;
(define device-mapping-service-type
(shepherd-service-type
'device-mapping
(match-lambda
(($ <mapped-device> source target
($ <mapped-device-type> open close))
(shepherd-service
(provision (list (symbol-append 'device-mapping- (string->symbol target))))
(requirement '(udev))
(documentation "Map a device node using Linux's device mapper.")
(start #~(lambda () #$(open source target)))
(stop #~(lambda _ (not #$(close source target))))
(respawn? #f)
;; Add the modules needed by LUKS-DEVICE-MAPPING.
;; FIXME: This info should be propagated via gexps.
(modules `((rnrs bytevectors) ;bytevector?
((gnu build file-systems)
#:select (find-partition-by-luks-uuid))
,@%default-modules))
(imported-modules `((gnu build file-systems)
,@%default-imported-modules)))))))
(define (device-mapping-service mapped-device)
"Return a service that sets up @var{mapped-device}."
(service device-mapping-service-type mapped-device))
\f
;;;
;;; Common device mappings.
;;;
(define (open-luks-device source target)
"Return a gexp that maps SOURCE to TARGET as a LUKS device, using
'cryptsetup'."
#~(let ((source #$source))
(zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup")
"open" "--type" "luks"
;; Note: We cannot use the "UUID=source" syntax here
;; because 'cryptsetup' implements it by searching the
;; udev-populated /dev/disk/by-id directory but udev may
;; be unavailable at the time we run this.
(if (bytevector? source)
(or (find-partition-by-luks-uuid source)
(error "LUKS partition not found" source))
source)
#$target))))
(define (close-luks-device source target)
"Return a gexp that closes TARGET, a LUKS device."
#~(zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup")
"close" #$target)))
(define luks-device-mapping
;; The type of LUKS mapped devices.
(mapped-device-kind
(open open-luks-device)
(close close-luks-device)))
;;; mapped-devices.scm ends here
|