How to trigger services restart after OpenBSD update

Author: Solène

Date: 25 September 2022

Tags: openbsd security deployment

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Introduction

Keeping an OpenBSD system up-to-date requires two daily operation:

updating the base system with the command: `/usr/sbin/syspatch`

updating the packages (if any) with the command: `/usr/sbin/pkg_add -u`

However, OpenBSD isn't very friendly with regard to what to do after upgrading: modified binaries should be restarted to use the new code, and a new kernel requires an upgrade

It's not useful to update if the newer binaries are never used.

Syspatch reboot

I wrote a small script to automatically reboot if syspatch deployed a new kernel. Instead of running syspatch from a cron job, you can run a script with this content:

#!/bin/sh

OUT=$(/usr/sbin/syspatch)
SUCCESS=$?

if [ "$SUCCESS" -eq 0 ]
then
    if echo "$OUT" | grep reboot >/dev/null
    then
        reboot
    fi
fi

It's not much, it runs syspatch and if the output contains "reboot", then a reboot of the system is done.

Binaries restart

It's getting more complicated when a running program is updated, whether it's a service with a rc.d script, or a program currently in use.

This would be nice to see something to help to restart them appropriately, I currently use the program `checkrestart` in a script like this:

checkrestart | grep smtpd && rcctl restart smtpd
checkrestart | grep httpd && rcctl restart httpd
checkrestart | grep dovecot && rcctl restart dovecot
checkrestart | grep lua && rcctl restart prosody

This works well for system services, except when the binary is different from the service name like for prosody, in which case you must know the exact name of the binary.

But for long-lived commands like a 24/7 emacs or an IRC client, there isn't any mechanism to handle it. At best, you can email you checkrestart output, or run checkrestart upon SSH login.

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