This fixes <https://bugs.gnu.org/39712>. The guix-daemon was preventing the cow-store umount, so restart it. Some udevd workers, using cow-store files might also still be around, so have some umount retries. * gnu/installer/final.scm (kill-cow-users): New procedure, (umount-cow-store): restart guix-daemon and kill all processes started from within the cow-store before trying to umount the store overlay. Also try 5 times to umount the overlay in case it is still busy.
		
			
				
	
	
		
			213 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
			
		
		
	
	
			213 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
| ;;; GNU Guix --- Functional package management for GNU
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| ;;; Copyright © 2018, 2020 Mathieu Othacehe <m.othacehe@gmail.com>
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| ;;; Copyright © 2019, 2020 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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| 
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| (define-module (gnu installer final)
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|   #:use-module (gnu installer newt page)
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|   #:use-module (gnu installer steps)
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|   #:use-module (gnu installer utils)
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|   #:use-module (gnu installer user)
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|   #:use-module (gnu services herd)
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|   #:use-module (guix build syscalls)
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|   #:use-module (guix build utils)
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|   #:use-module (gnu build accounts)
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|   #:use-module ((gnu system shadow) #:prefix sys:)
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|   #:use-module (rnrs io ports)
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|   #:use-module (srfi srfi-1)
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|   #:use-module (ice-9 ftw)
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|   #:use-module (ice-9 popen)
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|   #:use-module (ice-9 match)
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|   #:use-module (ice-9 format)
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|   #:use-module (ice-9 rdelim)
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|   #:export (install-system))
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| 
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| (define %seed
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|   (seed->random-state
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|    (logxor (getpid) (car (gettimeofday)))))
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| 
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| (define (integer->alphanumeric-char n)
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|   "Map N, an integer in the [0..62] range, to an alphanumeric character."
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|   (cond ((< n 10)
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|          (integer->char (+ (char->integer #\0) n)))
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|         ((< n 36)
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|          (integer->char (+ (char->integer #\A) (- n 10))))
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|         ((< n 62)
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|          (integer->char (+ (char->integer #\a) (- n 36))))
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|         (else
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|          (error "integer out of bounds" n))))
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| 
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| (define (random-string len)
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|   "Compute a random string of size LEN where each character is alphanumeric."
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|   (let loop ((chars '())
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|              (len len))
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|     (if (zero? len)
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|         (list->string chars)
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|         (let ((n (random 62 %seed)))
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|           (loop (cons (integer->alphanumeric-char n) chars)
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|                 (- len 1))))))
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| 
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| (define (create-user-database users root)
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|   "Create /etc/passwd, /etc/shadow, and /etc/group under ROOT for the given
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| USERS."
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|   (define etc
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|     (string-append root "/etc"))
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| 
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|   (define (salt)
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|     ;; "$6" gives us a SHA512 password hash; the random string must be taken
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|     ;; from the './0-9A-Za-z' alphabet (info "(libc) Passphrase Storage").
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|     (string-append "$6$" (random-string 10)))
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| 
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|   (define users*
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|     (map (lambda (user)
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|            (define root?
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|              (string=? "root" (user-name user)))
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| 
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|            (sys:user-account (name (user-name user))
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|                              (comment (user-real-name user))
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|                              (group "users")
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|                              (uid (if root? 0 #f))
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|                              (home-directory
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|                               (user-home-directory user))
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|                              (password (crypt (user-password user)
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|                                               (salt)))
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| 
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|                              ;; We need a string here, not a file-like, hence
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|                              ;; this choice.
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|                              (shell
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|                               "/run/current-system/profile/bin/bash")))
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|          users))
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| 
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|   (define-values (group password shadow)
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|     (user+group-databases users* sys:%base-groups
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|                           #:current-passwd '()
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|                           #:current-groups '()
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|                           #:current-shadow '()))
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| 
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|   (mkdir-p etc)
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|   (write-group group (string-append etc "/group"))
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|   (write-passwd password (string-append etc "/passwd"))
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|   (write-shadow shadow (string-append etc "/shadow")))
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| 
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| (define* (kill-cow-users cow-path #:key (spare '("udevd")))
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|   "Kill all processes that have references to the given COW-PATH in their
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| 'maps' file.  The process whose names are in SPARE list are spared."
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|   (define %not-nul
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|     (char-set-complement (char-set #\nul)))
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| 
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|   (let ((pids
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|          (filter-map (lambda (pid)
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|                        (call-with-input-file
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|                            (string-append "/proc/" pid "/maps")
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|                          (lambda (port)
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|                            (and (string-contains (get-string-all port)
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|                                                  cow-path)
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|                                 (string->number pid)))))
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|                      (scandir "/proc" string->number))))
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|     (for-each (lambda (pid)
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|                 ;; cmdline does not always exist.
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|                 (false-if-exception
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|                  (call-with-input-file
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|                      (string-append "/proc/" (number->string pid) "/cmdline")
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|                    (lambda (port)
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|                      (match (string-tokenize (read-string port) %not-nul)
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|                        ((argv0 _ ...)
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|                         (unless (member (pk (basename argv0)) spare)
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|                           (syslog "Killing process ~a~%" pid)
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|                           (kill pid SIGKILL)))
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|                        (_ #f))))))
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|               pids)))
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| 
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| (define (umount-cow-store)
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|   "Remove the store overlay and the bind-mount on /tmp created by the
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| cow-store service.  This procedure is very fragile and a better approach would
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| be much appreciated."
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| 
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|   ;; Remove when integrated in (gnu services herd).
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|   (define (restart-service name)
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|     (with-shepherd-action name ('restart) result
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|       result))
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| 
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|   (catch #t
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|     (lambda ()
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|       (let ((tmp-dir "/remove"))
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|         (mkdir-p tmp-dir)
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|         (mount (%store-directory) tmp-dir "" MS_MOVE)
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| 
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|         ;; The guix-daemon has possibly opened files from the cow-store,
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|         ;; restart it.
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|         (restart-service 'guix-daemon)
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| 
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|         ;; Kill all processes started while the cow-store was active (logins
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|         ;; on other TTYs for instance).
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|         (kill-cow-users tmp-dir)
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| 
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|         ;; Try to umount the store overlay. Some process such as udevd
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|         ;; workers might still be active, so do some retries.
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|         (let loop ((try 5))
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|           (sleep 1)
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|           (let ((umounted? (false-if-exception (umount tmp-dir))))
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|             (if (and (not umounted?) (> try 0))
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|                 (loop (- try 1))
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|                 (if umounted?
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|                     (syslog "Umounted ~a successfully.~%" tmp-dir)
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|                     (syslog "Failed to umount ~a.~%" tmp-dir)))))
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| 
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|         (umount "/tmp")))
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|     (lambda args
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|       (syslog "~a~%" args))))
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| 
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| (define* (install-system locale #:key (users '()))
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|   "Create /etc/shadow and /etc/passwd on the installation target for USERS.
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| Start COW-STORE service on target directory and launch guix install command in
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| a subshell.  LOCALE must be the locale name under which that command will run,
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| or #f.  Return #t on success and #f on failure."
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|   (let* ((options         (catch 'system-error
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|                             (lambda ()
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|                               ;; If this file exists, it can provide
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|                               ;; additional command-line options.
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|                               (call-with-input-file
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|                                   "/tmp/installer-system-init-options"
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|                                 read))
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|                             (const '())))
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|          (install-command (append (list "guix" "system" "init"
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|                                         "--fallback")
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|                                   options
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|                                   (list (%installer-configuration-file)
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|                                         (%installer-target-dir)))))
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|     (mkdir-p (%installer-target-dir))
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| 
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|     ;; We want to initialize user passwords but we don't want to store them in
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|     ;; the config file since the password hashes would end up world-readable
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|     ;; in the store.  Thus, create /etc/shadow & co. here such that, on the
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|     ;; first boot, the activation snippet that creates accounts will reuse the
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|     ;; passwords that we've put in there.
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|     (create-user-database users (%installer-target-dir))
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| 
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|     (dynamic-wind
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|       (lambda ()
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|         (start-service 'cow-store (list (%installer-target-dir))))
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|       (lambda ()
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|         (run-command install-command #:locale locale))
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|       (lambda ()
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|         (stop-service 'cow-store)
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|         ;; Remove the store overlay created at cow-store service start.
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|         ;; Failing to do that will result in further umount calls to fail
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|         ;; because the target device is seen as busy. See:
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|         ;; https://lists.gnu.org/archive/html/guix-devel/2018-12/msg00161.html.
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|         (umount-cow-store)
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|         #f))))
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