core/dbus-core/dbus.install

post_install() {
  getent group dbus >/dev/null || groupadd -g 81 dbus
  getent passwd dbus >/dev/null || useradd -c 'System message bus' -u 81 -g dbus -d '/' -s /bin/false dbus
  passwd -l dbus &>/dev/null
  dbus-uuidgen --ensure
  ln /var/lib/dbus/machine-id /etc/machine-id
}

post_upgrade() {
  post_install

  # Make sure new rc script can shutdown running dbus
  if [ -f run/dbus.pid -a -d run/dbus ]; then
    mv run/dbus.pid run/dbus/pid
  fi
}

post_remove() {
  if getent passwd dbus >/dev/null; then
    userdel dbus
  fi
  if getent group dbus >/dev/null; then
    groupdel dbus
  fi
}