Discovering list of open files from "kernel level" without using utils like lsof

[Garrett Cooper]

Hello,
	I'm trying to see whether it's possible to grab the list of files open
from a kernel level on FreeBSD, using a userland library interface as
opposed to lsof.
	I'm trying to see if there's a simple tool that I could code in C/C++
if necessary to spin down disks automatically to save power and disk
life. Plus, I think that lsof actually would probe the devices and 'wake
them up' instead of keeping them as-is. However, I could be wrong so if
I am please let me know.
TIA,
-Garrett