guix-devel/guix/scripts/system/reconfigure.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Alex Kost <alezost@gmail.com>
;;; Copyright © 2016, 2017, 2018 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
;;; Copyright © 2019 Christopher Baines <mail@cbaines.net>
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.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 (guix scripts system reconfigure)
#:autoload (gnu packages gnupg) (guile-gcrypt)
#:use-module (gnu bootloader)
#:use-module (gnu services)
#:use-module (gnu services herd)
#:use-module (gnu services shepherd)
#:use-module (gnu system)
#:use-module (guix gexp)
#:use-module (guix modules)
#:use-module (guix monads)
#:use-module (guix store)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:export (switch-system-program
switch-to-system
upgrade-services-program
upgrade-shepherd-services
install-bootloader-program
install-bootloader))
;;; Commentary:
;;;
;;; This module implements the "effectful" parts of system
;;; reconfiguration. Although building a system derivation is a pure
;;; operation, a number of impure operations must be carried out for the
;;; system configuration to be realized -- chiefly, creation of generation
;;; symlinks and invocation of activation scripts.
;;;
;;; Code:
;;;
;;; Profile creation.
;;;
(define* (switch-system-program os #:optional profile)
"Return an executable store item that, upon being evaluated, will create a
new generation of PROFILE pointing to the directory of OS, switch to it
atomically, and run OS's activation script."
(program-file
"switch-to-system.scm"
(with-extensions (list guile-gcrypt)
(with-imported-modules (source-module-closure '((guix config)
(guix profiles)
(guix utils)))
#~(begin
(use-modules (guix config)
(guix profiles)
(guix utils))
(define profile
(or #$profile (string-append %state-directory "/profiles/system")))
(let* ((number (1+ (generation-number profile)))
(generation (generation-file-name profile number)))
(switch-symlinks generation #$os)
(switch-symlinks profile generation)
(setenv "GUIX_NEW_SYSTEM" #$os)
(primitive-load #$(operating-system-activation-script os))))))))
(define* (switch-to-system eval os #:optional profile)
"Using EVAL, a monadic procedure taking a single G-Expression as an argument,
create a new generation of PROFILE pointing to the directory of OS, switch to
it atomically, and run OS's activation script."
(eval #~(primitive-load #$(switch-system-program os profile))))
;;;
;;; Services.
;;;
(define (running-services eval)
"Using EVAL, a monadic procedure taking a single G-Expression as an argument,
return the <live-service> objects that are currently running on MACHINE."
(define exp
(with-imported-modules '((gnu services herd))
#~(begin
(use-modules (gnu services herd))
(let ((services (current-services)))
(and services
;; 'live-service-running' is ignored, as we can't necessarily
;; serialize arbitrary objects. This should be fine for now,
;; since 'machine-current-services' is not exposed publicly,
;; and the resultant <live-service> objects are only used for
;; resolving service dependencies.
(map (lambda (service)
(list (live-service-provision service)
(live-service-requirement service)))
services))))))
(mlet %store-monad ((services (eval exp)))
(return (map (match-lambda
((provision requirement)
(live-service provision requirement #f)))
services))))
;; XXX: Currently, this does NOT attempt to restart running services. See
;; <https://issues.guix.info/issue/33508> for details.
(define (upgrade-services-program service-files to-start to-unload to-restart)
"Return an executable store item that, upon being evaluated, will upgrade
the Shepherd (PID 1) by unloading obsolete services and loading new
services. SERVICE-FILES is a list of Shepherd service files to load, and
TO-START, TO-UNLOAD, and TO-RESTART are lists of the Shepherd services'
canonical names (symbols)."
(program-file
"upgrade-shepherd-services.scm"
(with-imported-modules '((gnu services herd))
#~(begin
(use-modules (gnu services herd)
(srfi srfi-1))
;; Load the service files for any new services.
(load-services/safe '#$service-files)
;; Unload obsolete services and start new services.
(for-each unload-service '#$to-unload)
(for-each start-service '#$to-start)))))
(define* (upgrade-shepherd-services eval os)
"Using EVAL, a monadic procedure taking a single G-Expression as an argument,
upgrade the Shepherd (PID 1) by unloading obsolete services and loading new
services as defined by OS."
(define target-services
(service-value
(fold-services (operating-system-services os)
#:target-type shepherd-root-service-type)))
(mlet* %store-monad ((live-services (running-services eval)))
(let*-values (((to-unload to-restart)
(shepherd-service-upgrade live-services target-services)))
(let* ((to-unload (map live-service-canonical-name to-unload))
(to-restart (map shepherd-service-canonical-name to-restart))
(to-start (lset-difference eqv?
(map shepherd-service-canonical-name
target-services)
(map live-service-canonical-name
live-services)))
(service-files (map shepherd-service-file target-services)))
(eval #~(primitive-load #$(upgrade-services-program service-files
to-start
to-unload
to-restart)))))))
;;;
;;; Bootloader configuration.
;;;
(define (install-bootloader-program installer bootloader-package bootcfg
bootcfg-file device target)
"Return an executable store item that, upon being evaluated, will install
BOOTCFG to BOOTCFG-FILE, a target file name, on DEVICE, a file system device,
at TARGET, a mount point, and subsequently run INSTALLER from
BOOTLOADER-PACKAGE."
(program-file
"install-bootloader.scm"
(with-extensions (list guile-gcrypt)
(with-imported-modules (source-module-closure '((gnu build bootloader)
(gnu build install)
(guix store)
(guix utils)))
#~(begin
(use-modules (gnu build bootloader)
(gnu build install)
(guix build utils)
(guix store)
(guix utils)
(ice-9 binary-ports)
(srfi srfi-34)
(srfi srfi-35))
(let* ((gc-root (string-append #$target %gc-roots-directory "/bootcfg"))
(new-gc-root (string-append gc-root ".new")))
;; #$bootcfg has dependencies.
;; The bootloader magically loads the configuration from
;; (string-append #$target #$bootcfg-file) (for example
;; "/boot/grub/grub.cfg").
;; If we didn't do something special, the garbage collector
;; would remove the dependencies of #$bootcfg.
;; Register #$bootcfg as a GC root.
;; Preserve the previous activation's garbage collector root
;; until the bootloader installer has run, so that a failure in
;; the bootloader's installer script doesn't leave the user with
;; a broken installation.
(switch-symlinks new-gc-root #$bootcfg)
(install-boot-config #$bootcfg #$bootcfg-file #$target)
(when #$installer
(catch #t
(lambda ()
(#$installer #$bootloader-package #$device #$target))
(lambda args
(delete-file new-gc-root)
(apply throw args))))
;; We are sure that the installation of the bootloader
;; succeeded, so we can replace the old GC root by the new
;; GC root now.
(rename-file new-gc-root gc-root)))))))
(define* (install-bootloader eval configuration bootcfg
#:key
(run-installer? #t)
(target "/"))
"Using EVAL, a monadic procedure taking a single G-Expression as an argument,
configure the bootloader on TARGET such that OS will be booted by default and
additional configurations specified by MENU-ENTRIES can be selected."
(let* ((bootloader (bootloader-configuration-bootloader configuration))
(installer (and run-installer?
(bootloader-installer bootloader)))
(package (bootloader-package bootloader))
(device (bootloader-configuration-target configuration))
(bootcfg-file (bootloader-configuration-file bootloader)))
(eval #~(primitive-load #$(install-bootloader-program installer
package
bootcfg
bootcfg-file
device
target)))))