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