From e36d6ab24b7f405d191f7bf84f0db949c0ee72c0 Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Thu, 13 Feb 2025 11:12:13 +0100
Subject: services: Use ‘spawn-command’ instead of ‘fork’ + ‘waitpid’.
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Fixes <https://issues.guix.gnu.org/76315>.

This is more concise and more robust: these ‘waitpid’ calls would
compete with those made by shepherd’s event loop upon SIGCHLD, and they
could hang forever, as illustrated with ‘dhcp-client-service-type’
in <https://issues.guix.gnu.org/76315>.

* gnu/services/databases.scm (postgresql-role-shepherd-service): Use
‘spawn-command’ instead of ‘fork+exec-command’ followed by ‘waitpid’.
* gnu/services/networking.scm (dhcp-client-shepherd-service): Change
‘start’ to use ‘spawn-command’ instead of ‘fork+exec-command’ and
* gnu/services/web.scm (patchwork-django-admin-gexp): Use
‘spawn-command’ instead of ‘primitive-fork’ + ‘waitpid’.

Change-Id: I449290bfa46f8600e6ccdb5a6da990ad0cb7948c
Reported-by: Tomas Volf <~@wolfsden.cz>
---
 gnu/services/databases.scm | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

(limited to 'gnu/services/databases.scm')

diff --git a/gnu/services/databases.scm b/gnu/services/databases.scm
index e8a4acc996d..6530c6f0a12 100644
--- a/gnu/services/databases.scm
+++ b/gnu/services/databases.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2015 David Thompson <davet@gnu.org>
-;;; Copyright © 2015-2016, 2022-2023 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015-2016, 2022-2023, 2025 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2016 Leo Famulari <leo@famulari.name>
 ;;; Copyright © 2017 Christopher Baines <mail@cbaines.net>
 ;;; Copyright © 2018 Clément Lassieur <clement@lassieur.org>
@@ -448,12 +448,14 @@ rolname = '" ,name "')) as not_exists;\n"
            (one-shot? #t)
            (start
             #~(lambda args
-                (let ((pid (fork+exec-command
-                            #$(postgresql-create-roles config)
-                            #:user "postgres"
-                            #:group "postgres"
-                            #:log-file #$log)))
-                  (zero? (cdr (waitpid pid))))))
+                (zero? (spawn-command
+                        #$(postgresql-create-roles config)
+                        #:user "postgres"
+                        #:group "postgres"
+                        ;; XXX: As of Shepherd 1.0.2, #:log-file is not
+                        ;; supported.
+                        ;; #:log-file #$log
+                        ))))
            (documentation "Create PostgreSQL roles.")))))
 
 (define postgresql-role-service-type
-- 
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