Someone

#compdef zoneadm zonecfg zlogin

_zones () {
   case "$services" in
      zoneadm) _zoneadm "$@";;
      zonecfg) _zonecfg "$@";;
      zlogin) _zlogin "$@";;
      *) _message "Unknow service $service";;
   esac
}

_zlogin () {
   _arguments \
      '-l:username:_users' \
      '-C:console login:' \
      '*:zonename:'$zonelist

   _zlogin "$@"
}

zonelist () {
   local -a zones

   # Fetch zone lists from /etc/zones/index
   zones=(${${(a)"${(f)$(< /etc/zones/index)}"##\#*}//:*}) #" prevent vim become crazy

   # Remove global zone from list "
   zones[(r)global]=''

   return $zones
}

return 1


% zlogin
Unknow service zlogin