pdist-bootcheck

#! /bin/bash

set -e

if [ -e /.pdist_status ]; then
    now=$(date +%s)
    if [ $now -lt $(date +%s -d 2023-06-01) ]; then
        echo $(date -d $now): implausible system time
        exit 1
    fi
    echo "system time: $(date -d @$now)"
    pdist_time=$(stat -c%Y /.pdist_status)
    echo "pdist time:  $(date -d @$pdist_time)"
    pdist_age=$(( ($now - $pdist_time) /60 /60 /24 ))
    echo "pdist age:   $pdist_age days"
    if [ $pdist_age -ge 7 ]; then
        need_pdist_and_reboot=1
    elif [ $pdist_age -ge 1 ]; then
        need_async_pdist=1
    else
        echo no update required
    fi
else
    echo "no recorded update time"
    need_pdist_and_reboot=1
fi

if [ "$need_async_pdist" ]; then
    systemd-run --unit pdist-async-update --service-type=simple --remain-after-exit \
        netcat $(distmaster) 237
    echo triggered background update
elif [ "$need_pdist_and_reboot" ]; then
    if [[ -e /var/run/updatecheck.reboot-triggered ]]; then
        echo "Update and reboot required but prevented due to previous attempt"
        rm /var/run/updatecheck.reboot-triggered
        exit 1
    fi
    if (( $(stat -f -c %f /) * $(stat -f -c %s /) /1024/1024/1024 < 10)); then
        echo "Update and reboot required but prevented because of insufficient free disk space (<10G)"
        exit 1
    fi
    echo "Update and reboot required"
    touch /var/run/updatecheck.reboot-triggered
    sync /
    while true; do sleep 5; echo "System update in progress. Please be patient..."; done &
    netcat $(distmaster) 237
    mxgrub default
    systemctl start reboot.target --job-mode=replace-irreversibly
fi