fix #5009: avoid waiting for stdout eof of /etc/network/ scripts

[ifupdown2.git] / debian / patches / upstream / 0001-scheduler-avoid-waiting-for-stdout-eof-of-etc-networ.patch

From 1303d9211d82326f7c55d56db13eed66bb1c6535 Mon Sep 17 00:00:00 2001
From: Friedrich Weber <f.weber@proxmox.com>
Date: Tue, 26 Sep 2023 13:33:36 +0200
Subject: [PATCH] scheduler: avoid waiting for stdout eof of /etc/network/
 scripts

Scripts in /etc/network/ are executed using `exec_command` which
captures stdout by default, and thus waits for stdout end-of-file via
`Popen.communicate()`. However, this can cause hangs if the network
script executes a long-running command in the background. Can be
reproduced by putting the following (executable) script in
/etc/network/if-up.d/:

	#!/bin/sh
	sleep 5&

This script will cause `ifreload -a` to wait for 5 seconds per network
interface.

To avoid waiting, do not capture stdout when executing /etc/network/
scripts. This also improves compatibility with ifupdown, which runs
the above script in the background.

Signed-off-by: Friedrich Weber <f.weber@proxmox.com>
---
 ifupdown2/ifupdown/scheduler.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ifupdown2/ifupdown/scheduler.py b/ifupdown2/ifupdown/scheduler.py
index fda6ff2..e4d579f 100644
--- a/ifupdown2/ifupdown/scheduler.py
+++ b/ifupdown2/ifupdown/scheduler.py
@@ -142,7 +142,7 @@ class ifaceScheduler():
             for mname in ifupdownobj.script_ops.get(op, []):
                 ifupdownobj.logger.debug("%s: %s : running script %s" % (ifacename, op, mname))
                 try:
-                    utils.exec_command(mname, env=command_env)
+                    utils.exec_command(mname, env=command_env, stdout=False)
                 except Exception as e:
                     if "permission denied" in str(e).lower():
                         ifupdownobj.logger.warning('%s: %s %s' % (ifacename, op, str(e)))
-- 
2.39.2