summaryrefslogtreecommitdiff
path: root/gnu/system/mapped-devices.scm
blob: c19a8184533d30328f371bacb072fcd6ac2023a6 (about) (plain)
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
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014-2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Andreas Enge <andreas@enge.fr>
;;; Copyright © 2017, 2018 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2024 Tomas Volf <~@wolfsden.cz>
;;;
;;; 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) #:hide (file-name->module-name))
  #:use-module (guix i18n)
  #:use-module ((guix diagnostics)
                #:select (source-properties->location
                          formatted-message
                          &fix-hint
                          &error-location))
  #:use-module (guix deprecation)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu system uuid)
  #:autoload   (gnu build file-systems) (find-partition-by-luks-uuid)
  #:autoload   (gnu build linux-modules)
                 (missing-modules)
  #:autoload   (gnu packages cryptsetup) (cryptsetup-static)
  #:autoload   (gnu packages linux) (mdadm-static lvm2-static)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (ice-9 match)
  #:use-module (ice-9 format)
  #:export (%mapped-device
            mapped-device
            mapped-device?
            mapped-device-source
            mapped-device-target
            mapped-device-targets
            mapped-device-type
            mapped-device-location

            mapped-device-kind
            mapped-device-kind?
            mapped-device-kind-open
            mapped-device-kind-close
            mapped-device-kind-check

            device-mapping-service-type
            device-mapping-service

            check-device-initrd-modules           ;XXX: needs a better place

            luks-device-mapping
            luks-device-mapping-with-options
            raid-device-mapping
            lvm-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
  (targets   mapped-device-targets)               ;list of strings
  (type      mapped-device-type)                  ;<mapped-device-kind>
  (location  mapped-device-location
             (default (current-source-location)) (innate)))

(define-syntax mapped-device-compatibility-helper
  (syntax-rules (target)
    ((_ () (fields ...))
     (%mapped-device fields ...))
    ((_ ((target exp) rest ...) (others ...))
     (%mapped-device others ...
                      (targets (list exp))
                      rest ...))
    ((_ (field rest ...) (others ...))
     (mapped-device-compatibility-helper (rest ...)
                                         (others ... field)))))

(define-syntax-rule (mapped-device fields ...)
  "Build an <mapped-device> record, automatically converting 'target' field
specifications to 'targets'."
  (mapped-device-compatibility-helper (fields ...) ()))

(define-deprecated (mapped-device-target md)
  mapped-device-targets
  (car (mapped-device-targets md)))

(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))))
  (check     mapped-device-kind-check             ;source -> Boolean
             (default (const #t))))


;;;
;;; Device mapping as a Shepherd service.
;;;

(define device-mapping-service-type
  (shepherd-service-type
   'device-mapping
   (match-lambda
     (($ <mapped-device> source targets
                         ($ <mapped-device-type> open close))
      (shepherd-service
       (provision (list (symbol-append 'device-mapping- (string->symbol (string-join targets "-")))))
       (requirement '(udev))
       (documentation "Map a device node using Linux's device mapper.")
       (start #~(lambda () #$(open source targets)))
       (stop #~(lambda _ (not #$(close source targets))))
       (respawn? #f))))
   (description "Map a device node using Linux's device mapper.")))

(define (device-mapping-service mapped-device)
  "Return a service that sets up @var{mapped-device}."
  (service device-mapping-service-type mapped-device))


;;;
;;; Static checks.
;;;

(define (check-device-initrd-modules device linux-modules location)
  "Raise an error if DEVICE needs modules beyond LINUX-MODULES to operate.
DEVICE must be a \"/dev\" file name."
  (define missing
    ;; Attempt to determine missing modules.
    (catch 'system-error
      (lambda ()
        (missing-modules device linux-modules))

      ;; If we can't do that (e.g., EPERM), skip the whole thing.
      (const '())))

  (unless (null? missing)
    ;; Note: What we suggest here is a list of module names (e.g.,
    ;; "usb_storage"), not file names (e.g., "usb-storage.ko").  This is
    ;; OK because we have machinery that accepts both the hyphen and the
    ;; underscore version.
    (raise (make-compound-condition
            (formatted-message (G_ "you may need these modules \
in the initrd for ~a:~{ ~a~}")
                               device missing)
            (condition
             (&fix-hint
              (hint (format #f (G_ "Try adding them to the
@code{initrd-modules} field of your @code{operating-system} declaration, along
these lines:

@example
 (operating-system
   ;; @dots{}
   (initrd-modules (append (list~{ ~s~})
                           %base-initrd-modules)))
@end example

If you think this diagnostic is inaccurate, use the @option{--skip-checks}
option of @command{guix system}.\n")
                            missing))))
            (condition
             (&error-location
              (location (source-properties->location location))))))))


;;;
;;; Common device mappings.
;;;

(define* (open-luks-device source targets #:key key-file)
  "Return a gexp that maps SOURCE to TARGET as a LUKS device, using
'cryptsetup'."
  (with-imported-modules (source-module-closure
                          '((gnu build file-systems)
                            (guix build utils))) ;; For mkdir-p
    (match targets
      ((target)
       #~(let ((source #$(if (uuid? source)
                             (uuid-bytevector source)
                             source))
               (keyfile #$key-file))
           ;; XXX: 'use-modules' should be at the top level.
           (use-modules (rnrs bytevectors) ;bytevector?
                        ((gnu build file-systems)
                         #:select (find-partition-by-luks-uuid
                                   system*/tty))
                        ((guix build utils) #:select (mkdir-p)))

           ;; Create '/run/cryptsetup/' if it does not exist, as device locking
           ;; is mandatory for LUKS2.
           (mkdir-p "/run/cryptsetup/")

           ;; Use 'cryptsetup-static', not 'cryptsetup', to avoid pulling the
           ;; whole world inside the initrd (for when we're in an initrd).
           ;; 'cryptsetup open' requires standard input to be a tty to allow
           ;; for interaction but shepherd sets standard input to /dev/null;
           ;; thus, explicitly request a tty.
           (let ((partition
                  ;; 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)))
             ;; We want to fallback to the password unlock if the keyfile fails.
             (or (and keyfile
                      (zero? (system*/tty
                              #$(file-append cryptsetup-static "/sbin/cryptsetup")
                              "open" "--type" "luks"
                              "--key-file" keyfile
                              partition #$target)))
                 (zero? (system*/tty
                         #$(file-append cryptsetup-static "/sbin/cryptsetup")
                         "open" "--type" "luks"
                         partition #$target)))))))))

(define (close-luks-device source targets)
  "Return a gexp that closes TARGET, a LUKS device."
  (match targets
    ((target)
     #~(zero? (system* #$(file-append cryptsetup-static "/sbin/cryptsetup")
                       "close" #$target)))))

(define* (check-luks-device md #:key
                            needed-for-boot?
                            (initrd-modules '())
                            #:allow-other-keys
                            #:rest rest)
  "Ensure the source of MD is valid."
  (let ((source   (mapped-device-source md))
        (location (mapped-device-location md)))
    (or (not (zero? (getuid)))
        (if (uuid? source)
            (match (find-partition-by-luks-uuid (uuid-bytevector source))
              (#f
               (raise (make-compound-condition
                       (formatted-message (G_ "no LUKS partition with UUID '~a'")
                                          (uuid->string source))
                       (condition
                        (&error-location
                         (location (source-properties->location
                                    (mapped-device-location md))))))))
              ((? string? device)
               (check-device-initrd-modules device initrd-modules location)))
            (check-device-initrd-modules source initrd-modules location)))))

(define luks-device-mapping
  ;; The type of LUKS mapped devices.
  (mapped-device-kind
   (open open-luks-device)
   (close close-luks-device)
   (check check-luks-device)))

(define* (luks-device-mapping-with-options #:key key-file)
  "Return a luks-device-mapping object with open modified to pass the arguments
into the open-luks-device procedure."
  (mapped-device-kind
   (inherit luks-device-mapping)
   (open (λ (source targets) (open-luks-device source targets
                                               #:key-file key-file)))))

(define (open-raid-device sources targets)
  "Return a gexp that assembles SOURCES (a list of devices) to the RAID device
TARGET (e.g., \"/dev/md0\"), using 'mdadm'."
  (match targets
    ((target)
     #~(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 targets)
  "Return a gexp that stops the RAID device TARGET."
  (match targets
    ((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)))

(define (open-lvm-device source targets)
  #~(and
     (zero? (system* #$(file-append lvm2-static "/sbin/lvm")
                     "vgchange" "--activate" "ay" #$source))
     ; /dev/mapper nodes are usually created by udev, but udev may be unavailable at the time we run this. So we create them here.
     (zero? (system* #$(file-append lvm2-static "/sbin/lvm")
                     "vgscan" "--mknodes"))
     (every file-exists? (map (lambda (file) (string-append "/dev/mapper/" file))
                              '#$targets))))


(define (close-lvm-device source targets)
  #~(zero? (system* #$(file-append lvm2-static "/sbin/lvm")
                    "vgchange" "--activate" "n" #$source)))

(define lvm-device-mapping
  (mapped-device-kind
   (open open-lvm-device)
   (close close-lvm-device)))

;;; mapped-devices.scm ends here