Some specific questions about RPM programming
 

I found I introduced many specific usage of RPM. I cannot find answers for these questions elsewhere. It looks like nobody is using RPM in my way?

1) In rpm scripts, can I know my current dbpath I specified in command line?

2) When I'm installing a binary using RPM. I'm actually overwriting the exist binary. I found the process keeps running even it has been replaced by installer. Will that be any potential issue? Is that possible in my installer to detect the process is running and kill it?

3) Is that possible to detect what I've installed on this host? i.e. it likes to run "rpm -qa" in %pre. But I need to know my current dbpath.

4) Is that possible for me to know the packaging date of my current package in %pre or %post? I want to write some logic in %pre to compare the binary's date which I will replace with the binary I will use for replace (the binary in my current package).