me
/
guix
Archived
1
0
Fork 0
This repository has been archived on 2024-08-07. You can view files and clone it, but cannot push or open issues/pull-requests.
guix/gnu/system/mapped-devices.scm

182 lines
6.9 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters!

This file contains invisible Unicode characters that may be processed differently from what appears below. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to reveal hidden characters.

;;; 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