repair

#!/bin/sh

#
# repair
#
# Called by the watchdog service when it detects an on-going error. Tries to recover from the error,
# if it knows how.
# See <https://manpages.debian.org/testing/watchdog/watchdog.8.en.html> and
# <https://manpages.debian.org/testing/watchdog/watchdog.conf.5.en.html>.
#

# The first param is the error code.
case $1 in
# 100 ENETDOWN: network is down
# 101 ENETUNREACH: network is unreachable
100|101)
    # Take all network interfaces down.
    systemctl stop networking

    ip link | awk '/^[0-9]: / {print $2}' | sed 's/:.*//' |
    while read -r device; do
        ifconfig "${device}" down
    done

    # Bring all network interfaces back up.
    ip link | awk '/^[0-9]: / {print $2}' | sed 's/:.*//' |
    while read -r device; do
        ifconfig "${device}" up
    done

    systemctl start networking

    # watchdogd will check whether this actually did fix the problem. If it didn't (and
    # watchdog.conf was created following the instructions in README.md), watchdogd will reboot
    # the system anyway.
    exit 0;;
esac

# Report that we didn't repair the problem.
exit "$1"