post_install() {
  for _g in stapusr stapsys stapdev; do
    getent group $_g >/dev/null || groupadd -r $_g
  done

  chgrp stapusr usr/bin/stapbpf
  chmod 04110 usr/bin/stapbpf

  chgrp stapusr usr/bin/staprun
  chmod 04110 usr/bin/staprun
}

post_upgrade() {
  post_install $1
}

pre_remove() {
  for _g in stapusr stapsys stapdev; do
    groupdel $_g
  done
}