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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Andreas Enge <andreas@enge.fr>
;;; Copyright © 2017 Mark H Weaver <mhw@netris.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 (guix modules)
#:use-module (gnu services)
#:use-module (gnu services shepherd)
#:autoload (gnu packages cryptsetup) (cryptsetup-static)
#:autoload (gnu packages linux) (mdadm-static)
#: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
raid-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 | list of strings
(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)))))
;;;
;;; 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))))))
(define (device-mapping-service mapped-device)
"Return a service that sets up @var{mapped-device}."
(service device-mapping-service-type mapped-device))
;;;
;;; Common device mappings.
;;;
(define (open-luks-device source target)
"Return a gexp that maps SOURCE to TARGET as a LUKS device, using
'cryptsetup'."
(with-imported-modules (source-module-closure
'((gnu build file-systems)))
#~(let ((source #$source))
;; XXX: 'use-modules' should be at the top level.
(use-modules (rnrs bytevectors) ;bytevector?
((gnu build file-systems)
#:select (find-partition-by-luks-uuid)))
;; Use 'cryptsetup-static', not 'cryptsetup', to avoid pulling the
;; whole world inside the initrd (for when we're in an initrd).
(zero? (system* #$(file-append cryptsetup-static "/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 (let loop ((tries-left 10))
(and (positive? tries-left)
(or (find-partition-by-luks-uuid source)
;; If the underlying partition is
;; not found, try again after
;; waiting a second, up to ten
;; times. FIXME: This should be
;; dealt with in a more robust way.
(begin (sleep 1)
(loop (- tries-left 1))))))
(error "LUKS partition not found" source))
source)
#$target)))))
(define (close-luks-device source target)
"Return a gexp that closes TARGET, a LUKS device."
#~(zero? (system* #$(file-append cryptsetup-static "/sbin/cryptsetup")
"close" #$target)))
(define luks-device-mapping
;; The type of LUKS mapped devices.
(mapped-device-kind
(open open-luks-device)
(close close-luks-device)))
(define (open-raid-device sources target)
"Return a gexp that assembles SOURCES (a list of devices) to the RAID device
TARGET (e.g., \"/dev/md0\"), using 'mdadm'."
#~(let ((sources '#$sources)
;; XXX: We're not at the top level here. We could use a
;; non-top-level 'use-modules' form but that doesn't work when the
;; code is eval'd, like the Shepherd does.
(every (@ (srfi srfi-1) every))
(format (@ (ice-9 format) format)))
(let loop ((attempts 0))
(unless (every file-exists? sources)
(when (> attempts 20)
(error "RAID devices did not show up; bailing out"
sources))
(format #t "waiting for RAID source devices~{ ~a~}...~%"
sources)
(sleep 1)
(loop (+ 1 attempts))))
;; Use 'mdadm-static' rather than 'mdadm' to avoid pulling its whole
;; closure (80 MiB) in the initrd when a RAID device is needed for boot.
(zero? (apply system* #$(file-append mdadm-static "/sbin/mdadm")
"--assemble" #$target sources))))
(define (close-raid-device sources target)
"Return a gexp that stops the RAID device TARGET."
#~(zero? (system* #$(file-append mdadm-static "/sbin/mdadm")
"--stop" #$target)))
(define raid-device-mapping
;; The type of RAID mapped devices.
(mapped-device-kind
(open open-raid-device)
(close close-raid-device)))
;;; mapped-devices.scm ends here
|
