post_install() {
  if ! getent passwd dhcp &>/dev/null; then
    useradd -r -G adm -d /dev/null -s /bin/nologin dhcp >/dev/null
  fi

  [[ -f var/lib/dhcp/dhcpd.leases ]] || : >var/lib/dhcp/dhcpd.leases
  [[ -f var/lib/dhcp/dhcpd6.leases ]] || : >var/lib/dhcp/dhcpd6.leases

  if ! groups dhcp | grep adm &>/dev/null; then
    gpasswd -a dhcp adm >/dev/null
  fi
  dhcp_shell=$(getent passwd dhcp | cut -d: -f7)
  if [ "$dhcp_shell" != '/bin/nologin' ]; then
    chsh -s /bin/nologin dhcp &>/dev/null
  fi
}

post_upgrade() {
  if (( $(vercmp $2 4.2.4.2) < 0 )); then
    echo ">>> Lease directory moved from /var/state/dhcp"
    echo "    to /var/lib/dhcp. Move your old lease files"
    echo "    if you want to keep using them."
  fi

  post_install
}

post_remove() {
  if getent passwd dhcp &>/dev/null; then
    userdel dhcp >/dev/null
  fi
}