From: Carlo Zancanaro <carlo@zancanaro.id.au>
To: 66387@debbugs.gnu.org
Subject: [bug#66387] [PATCH] home: services: Fix race condition when detecting first login
Date: Wed, 11 Oct 2023 22:57:19 +1100 [thread overview]
Message-ID: <dd990558758d8bec9b4074f126c464e2f8a8ae6f.1697025388.git.carlo@zancanaro.id.au> (raw)
In-Reply-To: <87bkd8djri.fsf@zancanaro.id.au>
* gnu/home/services.scm (compute-on-first-login-script): Use open to
atomically check whether a file exists and create it if not.
---
gnu/home/services.scm | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/gnu/home/services.scm b/gnu/home/services.scm
index 8d53f2f4d3..7137925b30 100644
--- a/gnu/home/services.scm
+++ b/gnu/home/services.scm
@@ -2,6 +2,7 @@
;;; Copyright © 2021-2023 Andrew Tropin <andrew@trop.in>
;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
;;; Copyright © 2022-2023 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2023 Carlo Zancanaro <carlo@zancanaro.id.au>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -412,20 +413,29 @@ (define (compute-on-first-login-script _ gexps)
#~(begin
(use-modules (guix i18n)
(guix diagnostics))
+
+ (define (claim-first-run file-name)
+ (catch #t
+ (lambda ()
+ ;; This incantation will raise an error if the file at
+ ;; flag-file-path already exists, and will create it otherwise.
+ (close (open file-name (logior O_CREAT O_EXCL)))
+ #t)
+ (lambda _
+ #f)))
+
#$%initialize-gettext
(let* ((xdg-runtime-dir (or (getenv "XDG_RUNTIME_DIR")
(format #f "/run/user/~a" (getuid))))
(flag-file-path (string-append
- xdg-runtime-dir "/on-first-login-executed"))
- (touch (lambda (file-name)
- (call-with-output-file file-name (const #t)))))
+ xdg-runtime-dir "/on-first-login-executed")))
;; XDG_RUNTIME_DIR dissapears on logout, that means such trick
;; allows to launch on-first-login script on first login only
;; after complete logout/reboot.
(if (file-exists? xdg-runtime-dir)
- (unless (file-exists? flag-file-path)
- (begin #$@gexps (touch flag-file-path)))
+ (when (claim-first-run flag-file-path)
+ #$@gexps)
;; TRANSLATORS: 'on-first-login' is the name of a service and
;; shouldn't be translated
(warning (G_ "XDG_RUNTIME_DIR doesn't exists, on-first-login script
base-commit: 9ad9113fc238ee8de5191a5e15b5153fd149e9fa
--
2.41.0
next prev parent reply other threads:[~2023-10-11 11:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-07 11:59 [bug#66387] [PATCH] home: services: Fix race condition when detecting first login Carlo Zancanaro
2023-10-09 13:08 ` Carlo Zancanaro
2023-10-11 11:57 ` Carlo Zancanaro [this message]
2023-10-19 20:29 ` bug#66387: " Ludovic Courtès
2023-10-20 6:55 ` [bug#66387] " Andrew Tropin
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