pfSense

Remove update_dns_cache.sh it seems to have been used for hostnames in the filter ruleset which now is handled quite differently.

• Create two new functions lock($subsystem)/unlock() to have more reliable locking using semaphores.
  This function can sleep till the resource is free and can help find not well behaving code.
• Remove most of the config_lock/config_unlock logics on the whole scripts/pages it is an abuse of this....

Compare files

Works with multiple ip addresses.
FIXME: Compare tmp file with old addresses

Do not return a value for NXDOMAIN

Ensure dns cache folder exists

Add update_dns_cache.sh file which monitors dns addresses and looks for changes. A filter reload will be triggered if host ips differ

Initial revision