131 lines
4.5 KiB
Scheme
131 lines
4.5 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu system mapped-devices)
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#:use-module (guix gexp)
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#:use-module (guix records)
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#:use-module (gnu services)
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#:use-module (gnu services shepherd)
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#:autoload (gnu packages cryptsetup) (cryptsetup)
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#:use-module (srfi srfi-1)
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#:use-module (ice-9 match)
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#:export (mapped-device
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mapped-device?
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mapped-device-source
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mapped-device-target
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mapped-device-type
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mapped-device-kind
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mapped-device-kind?
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mapped-device-kind-open
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mapped-device-kind-close
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device-mapping-service-type
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device-mapping-service
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luks-device-mapping))
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;;; Commentary:
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;;;
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;;; This module supports "device mapping", a concept implemented by Linux's
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;;; device-mapper.
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;;;
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;;; Code:
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(define-record-type* <mapped-device> mapped-device
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make-mapped-device
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mapped-device?
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(source mapped-device-source) ;string
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(target mapped-device-target) ;string
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(type mapped-device-type)) ;<mapped-device-kind>
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(define-record-type* <mapped-device-type> mapped-device-kind
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make-mapped-device-kind
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mapped-device-kind?
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(open mapped-device-kind-open) ;source target -> gexp
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(close mapped-device-kind-close ;source target -> gexp
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(default (const #~(const #f)))))
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;;;
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;;; Device mapping as a Shepherd service.
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;;;
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(define device-mapping-service-type
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(shepherd-service-type
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'device-mapping
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(match-lambda
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(($ <mapped-device> source target
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($ <mapped-device-type> open close))
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(shepherd-service
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(provision (list (symbol-append 'device-mapping- (string->symbol target))))
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(requirement '(udev))
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(documentation "Map a device node using Linux's device mapper.")
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(start #~(lambda () #$(open source target)))
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(stop #~(lambda _ (not #$(close source target))))
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(respawn? #f)
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;; Add the modules needed by LUKS-DEVICE-MAPPING.
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;; FIXME: This info should be propagated via gexps.
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(modules `((rnrs bytevectors) ;bytevector?
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((gnu build file-systems)
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#:select (find-partition-by-luks-uuid))
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,@%default-modules))
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(imported-modules `((gnu build file-systems)
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,@%default-imported-modules)))))))
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(define (device-mapping-service mapped-device)
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"Return a service that sets up @var{mapped-device}."
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(service device-mapping-service-type mapped-device))
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;;;
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;;; Common device mappings.
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;;;
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(define (open-luks-device source target)
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"Return a gexp that maps SOURCE to TARGET as a LUKS device, using
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'cryptsetup'."
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#~(let ((source #$source))
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(zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup")
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"open" "--type" "luks"
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;; Note: We cannot use the "UUID=source" syntax here
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;; because 'cryptsetup' implements it by searching the
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;; udev-populated /dev/disk/by-id directory but udev may
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;; be unavailable at the time we run this.
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(if (bytevector? source)
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(or (find-partition-by-luks-uuid source)
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(error "LUKS partition not found" source))
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source)
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#$target))))
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(define (close-luks-device source target)
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"Return a gexp that closes TARGET, a LUKS device."
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#~(zero? (system* (string-append #$cryptsetup "/sbin/cryptsetup")
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"close" #$target)))
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(define luks-device-mapping
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;; The type of LUKS mapped devices.
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(mapped-device-kind
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(open open-luks-device)
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(close close-luks-device)))
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;;; mapped-devices.scm ends here
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