Update: lock handling tweaks.

Update: lock handling tweaks.

Move the rule lock to inside the if condition block because part of the rule is still being read.

Add missing unlock for other process active lock before break.
Relocate the other process active lock in some cases to be after the last access to the rule.

Utilize process r/w locks around starting and joining the main threads.

On exit, check to see if id_exit thread is actually used before attempting to join it.