A shell script installs and configures some services and applications in a Solaris instance. One of these services is NTP - but NTP cannot run in a non-global zone (well it can, but xntpd fails when it tries to adjust the clock; instead the zone inherits the time from the global zone).
How can a shell script tell that it is indeed running in a non-global Solaris zone, so that it can skip the NTP configuration step in those cases?