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1 | ;;; GNU Guix --- Functional package management for GNU |
2 | ;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org> | |
3 | ;;; | |
4 | ;;; This file is part of GNU Guix. | |
5 | ;;; | |
6 | ;;; GNU Guix is free software; you can redistribute it and/or modify it | |
7 | ;;; under the terms of the GNU General Public License as published by | |
8 | ;;; the Free Software Foundation; either version 3 of the License, or (at | |
9 | ;;; your option) any later version. | |
10 | ;;; | |
11 | ;;; GNU Guix is distributed in the hope that it will be useful, but | |
12 | ;;; WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ;;; GNU General Public License for more details. | |
15 | ;;; | |
16 | ;;; You should have received a copy of the GNU General Public License | |
17 | ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. | |
18 | ||
19 | (define-module (gnu system mapped-devices) | |
374f14c2 | 20 | #:use-module (guix gexp) |
060d62a7 | 21 | #:use-module (guix records) |
1ea507bc LC |
22 | #:use-module (gnu services) |
23 | #:use-module (gnu services shepherd) | |
374f14c2 | 24 | #:autoload (gnu packages cryptsetup) (cryptsetup) |
ffba7d49 | 25 | #:use-module (srfi srfi-1) |
1ea507bc | 26 | #:use-module (ice-9 match) |
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27 | #:export (mapped-device |
28 | mapped-device? | |
29 | mapped-device-source | |
30 | mapped-device-target | |
31 | mapped-device-type | |
32 | ||
33 | mapped-device-kind | |
34 | mapped-device-kind? | |
35 | mapped-device-kind-open | |
374f14c2 LC |
36 | mapped-device-kind-close |
37 | ||
1ea507bc LC |
38 | device-mapping-service-type |
39 | device-mapping-service | |
40 | ||
374f14c2 | 41 | luks-device-mapping)) |
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42 | |
43 | ;;; Commentary: | |
44 | ;;; | |
45 | ;;; This module supports "device mapping", a concept implemented by Linux's | |
46 | ;;; device-mapper. | |
47 | ;;; | |
48 | ;;; Code: | |
49 | ||
50 | (define-record-type* <mapped-device> mapped-device | |
51 | make-mapped-device | |
52 | mapped-device? | |
53 | (source mapped-device-source) ;string | |
54 | (target mapped-device-target) ;string | |
55 | (type mapped-device-type)) ;<mapped-device-kind> | |
56 | ||
57 | (define-record-type* <mapped-device-type> mapped-device-kind | |
58 | make-mapped-device-kind | |
59 | mapped-device-kind? | |
60 | (open mapped-device-kind-open) ;source target -> gexp | |
61 | (close mapped-device-kind-close ;source target -> gexp | |
62 | (default (const #~(const #f))))) | |
63 | ||
374f14c2 | 64 | \f |
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65 | ;;; |
66 | ;;; Device mapping as a Shepherd service. | |
67 | ;;; | |
68 | ||
69 | (define device-mapping-service-type | |
70 | (shepherd-service-type | |
71 | 'device-mapping | |
72 | (match-lambda | |
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73 | (($ <mapped-device> source target |
74 | ($ <mapped-device-type> open close)) | |
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75 | (shepherd-service |
76 | (provision (list (symbol-append 'device-mapping- (string->symbol target)))) | |
77 | (requirement '(udev)) | |
78 | (documentation "Map a device node using Linux's device mapper.") | |
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79 | (start #~(lambda () #$(open source target))) |
80 | (stop #~(lambda _ (not #$(close source target)))) | |
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81 | (respawn? #f) |
82 | ||
83 | ;; Add the modules needed by LUKS-DEVICE-MAPPING. | |
84 | ;; FIXME: This info should be propagated via gexps. | |
85 | (modules `((rnrs bytevectors) ;bytevector? | |
86 | ((gnu build file-systems) | |
87 | #:select (find-partition-by-luks-uuid)) | |
88 | ,@%default-modules)) | |
89 | (imported-modules `((gnu build file-systems) | |
90 | ,@%default-imported-modules))))))) | |
1ea507bc | 91 | |
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92 | (define (device-mapping-service mapped-device) |
93 | "Return a service that sets up @var{mapped-device}." | |
94 | (service device-mapping-service-type mapped-device)) | |
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95 | |
96 | \f | |
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97 | ;;; |
98 | ;;; Common device mappings. | |
99 | ;;; | |
100 | ||
101 | (define (open-luks-device source target) | |
102 | "Return a gexp that maps SOURCE to TARGET as a LUKS device, using | |
103 | 'cryptsetup'." | |
ffba7d49 LC |
104 | #~(let ((source #$source)) |
105 | (zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup") | |
106 | "open" "--type" "luks" | |
107 | ||
108 | ;; Note: We cannot use the "UUID=source" syntax here | |
109 | ;; because 'cryptsetup' implements it by searching the | |
110 | ;; udev-populated /dev/disk/by-id directory but udev may | |
111 | ;; be unavailable at the time we run this. | |
112 | (if (bytevector? source) | |
113 | (or (find-partition-by-luks-uuid source) | |
114 | (error "LUKS partition not found" source)) | |
115 | source) | |
116 | ||
117 | #$target)))) | |
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118 | |
119 | (define (close-luks-device source target) | |
120 | "Return a gexp that closes TARGET, a LUKS device." | |
121 | #~(zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup") | |
122 | "close" #$target))) | |
123 | ||
124 | (define luks-device-mapping | |
125 | ;; The type of LUKS mapped devices. | |
126 | (mapped-device-kind | |
127 | (open open-luks-device) | |
128 | (close close-luks-device))) | |
129 | ||
060d62a7 | 130 | ;;; mapped-devices.scm ends here |