installer: Add dry-run?

This allows running the installer without root privileges.  Do something like

    ./pre-inst-env guix repl
    ,use (guix)
    ,use (gnu installer)
    (installer-program #:dry-run? #t)
    ,build $1
    =>
    "/gnu/store/...-installer-program"

and run

    /gnu/store/...-installer-program

* gnu/installer/newt.scm (locale-page): Add #:dry-run? parameter.
(keymap-page): Likewise.
* gnu/installer/newt/keymap.scm (run-keymap-page): Likewise.
* gnu/installer/steps.scm (run-installer-steps): Likewise.  Use it to skip
writing to socket.
* gnu/installer/newt/final.scm (run-final-page): Rename to...
(run-final-page-install): ...this.
(dry-run-final-page, run-final-page): New procedures.
* gnu/installer/parted.scm (bootloader-configuration): Cater for empty user
partitions.
* gnu/installer/utils.scm (dry-run-command): New procedure.
* gnu/installer.scm (compute-locale-step): Add #:dry-run? parameter.  Use it
to avoid actually applying locale.
(compute-keymap-step): Add dry-run? parameter.  Pass it to
keymap-page.
(installer-program): Add #:dry-run? parameter.  If #:true
avoid writing to /proc, use dry-run-command, skip sync and reboot, and pass
dry-run? to...
(installer-steps): ...here.  Add #:dry-run? parameter.  Use it to disable
skip network, substitutes, partitioning pages, and pass it to...
compute-locale-step, compute-keymap-step, and final-page.

Change-Id: I0ff4c3b0a0c69539af617c27ba37654beed44619

1 files changed, 19 insertions, 1 deletions

diff --git a/gnu/installer/newt/final.scm b/gnu/installer/newt/final.scm
index 9f950a0551..c4e53f6d79 100644
--- a/gnu/installer/newt/final.scm
+++ b/gnu/installer/newt/final.scm
@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2018, 2020 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2019, 2020 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2024 Janneke Nieuwenhuizen <janneke@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -106,7 +107,7 @@ a specific step, or restart the installer."))
     (newt-resume)
     install-ok?))
 
-(define (run-final-page result prev-steps)
+(define (run-final-page-install result prev-steps)
   (define (wait-for-clients)
     (unless (null? (current-clients))
       (installer-log-line "waiting with clients before starting final step")
@@ -133,3 +134,20 @@ a specific step, or restart the installer."))
     (if install-ok?
         (run-install-success-page)
         (run-install-failed-page))))
+
+(define (dry-run-final-page result prev-steps)
+  (installer-log-line "proceeding with final step -- dry-run")
+  (let* ((configuration   (format-configuration prev-steps result))
+         (user-partitions (result-step result 'partition))
+         (locale          (result-step result 'locale))
+         (users           (result-step result 'user))
+         (file            (configuration->file configuration))
+         (install-ok?     (run-config-display-page #:locale locale)))
+    (if install-ok?
+        (run-install-success-page)
+        (run-install-failed-page))))
+
+(define (run-final-page result prev-steps dry-run?)
+  (if dry-run?
+      (dry-run-final-page result prev-steps)
+      (run-final-page-install result prev-steps)))