[jackhill/guix/guix.git] / gnu / system / mapped-devices.scm

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Andreas Enge <andreas@enge.fr>
;;; Copyright © 2017, 2018 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) #: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 (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)
  #: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-source
            mapped-device-target
            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
            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>
  (location  mapped-device-location
             (default (current-source-location)) (innate)))

(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))))

\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))

\f
;;;
;;; 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))))))))

\f
;;;
;;; 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 #$(if (uuid? source)
                          (uuid-bytevector 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* (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 (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
Commit	Line	Data
060d62a7	1	;;; GNU Guix --- Functional package management for GNU
db170ee9	2	;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
97c8aef1	3	;;; Copyright © 2016 Andreas Enge <andreas@enge.fr>
3e5783e2	4	;;; Copyright © 2017, 2018 Mark H Weaver <mhw@netris.org>
060d62a7 LC	5	;;;
	6	;;; This file is part of GNU Guix.
	7	;;;
	8	;;; GNU Guix is free software; you can redistribute it and/or modify it
	9	;;; under the terms of the GNU General Public License as published by
	10	;;; the Free Software Foundation; either version 3 of the License, or (at
	11	;;; your option) any later version.
	12	;;;
	13	;;; GNU Guix is distributed in the hope that it will be useful, but
	14	;;; WITHOUT ANY WARRANTY; without even the implied warranty of
	15	;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	;;; GNU General Public License for more details.
	17	;;;
	18	;;; You should have received a copy of the GNU General Public License
	19	;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
	20
	21	(define-module (gnu system mapped-devices)
374f14c2	22	#:use-module (guix gexp)
060d62a7	23	#:use-module (guix records)
d2a1cf45	24	#:use-module ((guix modules) #:hide (file-name->module-name))
42ff7d3b	25	#:use-module (guix i18n)
f9a8dd05	26	#:use-module ((guix diagnostics)
42ff7d3b	27	#:select (source-properties->location
d51bfe24	28	formatted-message
8ab10c19	29	&fix-hint
42ff7d3b	30	&error-location))
1ea507bc LC	31	#:use-module (gnu services)
1ea507bc LC	32	#:use-module (gnu services shepherd)
9b336338	33	#:use-module (gnu system uuid)
42ff7d3b	34	#:autoload (gnu build file-systems) (find-partition-by-luks-uuid)
8ab10c19	35	#:autoload (gnu build linux-modules)
4cd386af	36	(missing-modules)
b7d408ec	37	#:autoload (gnu packages cryptsetup) (cryptsetup-static)
4ed2f515	38	#:autoload (gnu packages linux) (mdadm-static)
ffba7d49	39	#:use-module (srfi srfi-1)
424cea80	40	#:use-module (srfi srfi-26)
42ff7d3b LC	41	#:use-module (srfi srfi-34)
42ff7d3b LC	42	#:use-module (srfi srfi-35)
1ea507bc	43	#:use-module (ice-9 match)
db170ee9	44	#:use-module (ice-9 format)
060d62a7 LC	45	#:export (mapped-device
	46	mapped-device?
	47	mapped-device-source
	48	mapped-device-target
	49	mapped-device-type
4ca90ff5	50	mapped-device-location
060d62a7 LC	51
	52	mapped-device-kind
	53	mapped-device-kind?
	54	mapped-device-kind-open
374f14c2	55	mapped-device-kind-close
4ca90ff5	56	mapped-device-kind-check
374f14c2	57
1ea507bc LC	58	device-mapping-service-type
	59	device-mapping-service
	60
8ab10c19 LC	61	check-device-initrd-modules ;XXX: needs a better place
8ab10c19 LC	62
97c8aef1 AE	63	luks-device-mapping
97c8aef1 AE	64	raid-device-mapping))
060d62a7 LC	65
	66	;;; Commentary:
	67	;;;
	68	;;; This module supports "device mapping", a concept implemented by Linux's
	69	;;; device-mapper.
	70	;;;
	71	;;; Code:
	72
	73	(define-record-type* <mapped-device> mapped-device
	74	make-mapped-device
	75	mapped-device?
d6d1cea6	76	(source mapped-device-source) ;string \| list of strings
060d62a7	77	(target mapped-device-target) ;string
4ca90ff5 LC	78	(type mapped-device-type) ;<mapped-device-kind>
	79	(location mapped-device-location
	80	(default (current-source-location)) (innate)))
060d62a7 LC	81
	82	(define-record-type* <mapped-device-type> mapped-device-kind
	83	make-mapped-device-kind
	84	mapped-device-kind?
	85	(open mapped-device-kind-open) ;source target -> gexp
	86	(close mapped-device-kind-close ;source target -> gexp
4ca90ff5 LC	87	(default (const #~(const #f))))
	88	(check mapped-device-kind-check ;source -> Boolean
	89	(default (const #t))))
060d62a7	90
374f14c2	91	\f
1ea507bc LC	92	;;;
	93	;;; Device mapping as a Shepherd service.
	94	;;;
	95
	96	(define device-mapping-service-type
	97	(shepherd-service-type
	98	'device-mapping
	99	(match-lambda
4da8c19e LC	100	(($ <mapped-device> source target
4da8c19e LC	101	($ <mapped-device-type> open close))
1ea507bc LC	102	(shepherd-service
	103	(provision (list (symbol-append 'device-mapping- (string->symbol target))))
	104	(requirement '(udev))
	105	(documentation "Map a device node using Linux's device mapper.")
4da8c19e LC	106	(start #~(lambda () #$(open source target)))
4da8c19e LC	107	(stop #~(lambda _ (not #$(close source target))))
dfe06f6e	108	(respawn? #f))))))
1ea507bc	109
4da8c19e LC	110	(define (device-mapping-service mapped-device)
	111	"Return a service that sets up @var{mapped-device}."
	112	(service device-mapping-service-type mapped-device))
1ea507bc LC	113
1ea507bc LC	114	\f
8ab10c19 LC	115	;;;
	116	;;; Static checks.
	117	;;;
	118
	119	(define (check-device-initrd-modules device linux-modules location)
	120	"Raise an error if DEVICE needs modules beyond LINUX-MODULES to operate.
	121	DEVICE must be a \"/dev\" file name."
4cd386af LC	122	(define missing
4cd386af LC	123	;; Attempt to determine missing modules.
8ab10c19 LC	124	(catch 'system-error
8ab10c19 LC	125	(lambda ()
4cd386af LC	126	(missing-modules device linux-modules))
	127
	128	;; If we can't do that (e.g., EPERM), skip the whole thing.
	129	(const '())))
	130
	131	(unless (null? missing)
	132	;; Note: What we suggest here is a list of module names (e.g.,
	133	;; "usb_storage"), not file names (e.g., "usb-storage.ko"). This is
	134	;; OK because we have machinery that accepts both the hyphen and the
	135	;; underscore version.
d51bfe24 LC	136	(raise (make-compound-condition
d51bfe24 LC	137	(formatted-message (G_ "you may need these modules \
8ab10c19	138	in the initrd for ~a:~{ ~a~}")
d51bfe24 LC	139	device missing)
	140	(condition
	141	(&fix-hint
	142	(hint (format #f (G_ "Try adding them to the
8ab10c19 LC	143	@code{initrd-modules} field of your @code{operating-system} declaration, along
	144	these lines:
	145
	146	@example
	147	(operating-system
	148	;; @dots{}
	149	(initrd-modules (append (list~{ ~s~})
	150	%base-initrd-modules)))
88600acc LC	151	@end example
	152
	153	If you think this diagnostic is inaccurate, use the @option{--skip-checks}
	154	option of @command{guix system}.\n")
d51bfe24 LC	155	missing))))
	156	(condition
	157	(&error-location
	158	(location (source-properties->location location))))))))
8ab10c19 LC	159
8ab10c19 LC	160	\f
374f14c2 LC	161	;;;
	162	;;; Common device mappings.
	163	;;;
	164
	165	(define (open-luks-device source target)
	166	"Return a gexp that maps SOURCE to TARGET as a LUKS device, using
	167	'cryptsetup'."
239c6e27 LC	168	(with-imported-modules (source-module-closure
239c6e27 LC	169	'((gnu build file-systems)))
9b336338 LC	170	#~(let ((source #$(if (uuid? source)
	171	(uuid-bytevector source)
	172	source)))
dfe06f6e LC	173	;; XXX: 'use-modules' should be at the top level.
	174	(use-modules (rnrs bytevectors) ;bytevector?
	175	((gnu build file-systems)
	176	#:select (find-partition-by-luks-uuid)))
	177
b7d408ec LC	178	;; Use 'cryptsetup-static', not 'cryptsetup', to avoid pulling the
	179	;; whole world inside the initrd (for when we're in an initrd).
	180	(zero? (system* #$(file-append cryptsetup-static "/sbin/cryptsetup")
a91c3fc7 LC	181	"open" "--type" "luks"
	182
	183	;; Note: We cannot use the "UUID=source" syntax here
	184	;; because 'cryptsetup' implements it by searching the
	185	;; udev-populated /dev/disk/by-id directory but udev may
	186	;; be unavailable at the time we run this.
	187	(if (bytevector? source)
f45878a8 MW	188	(or (let loop ((tries-left 10))
	189	(and (positive? tries-left)
	190	(or (find-partition-by-luks-uuid source)
	191	;; If the underlying partition is
	192	;; not found, try again after
	193	;; waiting a second, up to ten
	194	;; times. FIXME: This should be
	195	;; dealt with in a more robust way.
	196	(begin (sleep 1)
	197	(loop (- tries-left 1))))))
a91c3fc7 LC	198	(error "LUKS partition not found" source))
	199	source)
	200
	201	#$target)))))
374f14c2 LC	202
	203	(define (close-luks-device source target)
	204	"Return a gexp that closes TARGET, a LUKS device."
b7d408ec	205	#~(zero? (system* #$(file-append cryptsetup-static "/sbin/cryptsetup")
374f14c2 LC	206	"close" #$target)))
374f14c2 LC	207
424cea80 LC	208	(define* (check-luks-device md #:key
	209	needed-for-boot?
	210	(initrd-modules '())
	211	#:allow-other-keys
	212	#:rest rest)
42ff7d3b	213	"Ensure the source of MD is valid."
424cea80 LC	214	(let ((source (mapped-device-source md))
	215	(location (mapped-device-location md)))
	216	(or (not (zero? (getuid)))
	217	(if (uuid? source)
	218	(match (find-partition-by-luks-uuid (uuid-bytevector source))
	219	(#f
d51bfe24 LC	220	(raise (make-compound-condition
	221	(formatted-message (G_ "no LUKS partition with UUID '~a'")
	222	(uuid->string source))
	223	(condition
	224	(&error-location
	225	(location (source-properties->location
	226	(mapped-device-location md))))))))
424cea80 LC	227	((? string? device)
	228	(check-device-initrd-modules device initrd-modules location)))
	229	(check-device-initrd-modules source initrd-modules location)))))
42ff7d3b	230
374f14c2 LC	231	(define luks-device-mapping
	232	;; The type of LUKS mapped devices.
	233	(mapped-device-kind
	234	(open open-luks-device)
42ff7d3b LC	235	(close close-luks-device)
42ff7d3b LC	236	(check check-luks-device)))
374f14c2	237
7f8ad82b LC	238	(define (open-raid-device sources target)
	239	"Return a gexp that assembles SOURCES (a list of devices) to the RAID device
	240	TARGET (e.g., \"/dev/md0\"), using 'mdadm'."
10618627 LC	241	#~(let ((sources '#$sources)
	242
	243	;; XXX: We're not at the top level here. We could use a
	244	;; non-top-level 'use-modules' form but that doesn't work when the
	245	;; code is eval'd, like the Shepherd does.
	246	(every (@ (srfi srfi-1) every))
	247	(format (@ (ice-9 format) format)))
	248	(let loop ((attempts 0))
	249	(unless (every file-exists? sources)
	250	(when (> attempts 20)
	251	(error "RAID devices did not show up; bailing out"
	252	sources))
	253
	254	(format #t "waiting for RAID source devices~{ ~a~}...~%"
	255	sources)
	256	(sleep 1)
	257	(loop (+ 1 attempts))))
	258
4ed2f515 LC	259	;; Use 'mdadm-static' rather than 'mdadm' to avoid pulling its whole
	260	;; closure (80 MiB) in the initrd when a RAID device is needed for boot.
	261	(zero? (apply system* #$(file-append mdadm-static "/sbin/mdadm")
6e52376d	262	"--assemble" #$target sources))))
7f8ad82b LC	263
7f8ad82b LC	264	(define (close-raid-device sources target)
97c8aef1	265	"Return a gexp that stops the RAID device TARGET."
4ed2f515	266	#~(zero? (system* #$(file-append mdadm-static "/sbin/mdadm")
97c8aef1 AE	267	"--stop" #$target)))
	268
	269	(define raid-device-mapping
	270	;; The type of RAID mapped devices.
	271	(mapped-device-kind
	272	(open open-raid-device)
	273	(close close-raid-device)))
	274
060d62a7	275	;;; mapped-devices.scm ends here