#!/bin/sh
# check if package system is locked
# return 0 if unlocked, 2 if locked, 1 on error
set -e

for f in /var/lib/dpkg/lock /var/cache/apt/archives/lock \
    /var/lib/apt/lists/lock /run/unattended-upgrades.lock; do
    [ -e $f ] || continue

    # fuser succeeds if there is at least one user
    if fuser $f; then
        exit 2
    fi
done

exit 0