From 8452fdaccfa05c061ae5ca3d39f0228a8b9a347c Mon Sep 17 00:00:00 2001 From: Arun Isaac Date: Mon, 13 Jun 2022 17:03:06 +0530 Subject: utils: Make switch-symlinks robust against interruption. * guix/build/utils.scm (switch-symlinks): Delete pivot link if it already exists. Co-authored-by: Maxime Devos --- guix/build/utils.scm | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'guix/build/utils.scm') diff --git a/guix/build/utils.scm b/guix/build/utils.scm index ce7bdb2024..5ea3b98353 100644 --- a/guix/build/utils.scm +++ b/guix/build/utils.scm @@ -3,11 +3,11 @@ ;;; Copyright © 2013 Andreas Enge ;;; Copyright © 2013 Nikita Karetnikov ;;; Copyright © 2015, 2018, 2021 Mark H Weaver -;;; Copyright © 2018 Arun Isaac +;;; Copyright © 2018, 2022 Arun Isaac ;;; Copyright © 2018, 2019 Ricardo Wurmus ;;; Copyright © 2020 Efraim Flashner ;;; Copyright © 2020, 2021 Maxim Cournoyer -;;; Copyright © 2021 Maxime Devos +;;; Copyright © 2021, 2022 Maxime Devos ;;; Copyright © 2021 Brendan Tildesley ;;; ;;; This file is part of GNU Guix. @@ -245,7 +245,19 @@ (define (switch-symlinks link target) "Atomically switch LINK, a symbolic link, to point to TARGET. Works both when LINK already exists and when it does not." (let ((pivot (string-append link ".new"))) - (symlink target pivot) + ;; Create pivot link, deleting it if it already exists. This can + ;; happen if a previous switch-symlinks was interrupted. + (let symlink/remove-old () + (catch 'system-error + (lambda () + (symlink target pivot)) + (lambda args + (if (= (system-error-errno args) EEXIST) + (begin + ;; Remove old link and retry. + (delete-file pivot) + (symlink/remove-old)) + (apply throw args))))) (rename-file pivot link))) (define (call-with-temporary-output-file proc) -- cgit v1.2.3