>>The original poster should note that what he's trying to do is hardly novel or original, and most any major company's data center will have >>security policies requiring such accounting, and have generally thought of ways to do it securely. I'd avoid rolling my own, as this is definitely >>an area that you want to build upon the work of others, as there are a million little things you have to account for or else your installation is >>vulnerable to being circumvented.

actually, I'm writing this FOR major company's data centers, precisely because no such tool exists to do this in a foolproof manner.

It may be because attempting it in userspace is just not possible...