PREIN

/bin/sh

/usr/share/rpm-helper/add-user dbus $1 messagebus / /sbin/nologin 
/usr/share/rpm-helper/add-group dbus $1 daemon messagebus

PREUN

/bin/sh

/usr/share/rpm-helper/del-service dbus $1 messagebus

POSTIN

/bin/sh

if [ "$1" = "1" ]; then 
   /usr/bin/dbus-uuidgen --ensure
  /sbin/chkconfig --add messagebus  || /bin/true
fi

POSTUN

/bin/sh

/usr/share/rpm-helper/del-user dbus $1 messagebus 
/usr/share/rpm-helper/del-group dbus $1 daemon

Triggers

dbus < 0.21-4mdk

/bin/sh

/sbin/chkconfig --del messagebus
/sbin/chkconfig --add messagebus