Q. I need to configure FreeBSD kernel but not able to find out source code in /usr/src/sys directory. How do I install FreeBSD source code?
A.Your kernel and all related source code is located at /usr/src/sys directory which is also accessible through the /sys path.
If there is not a /usr/src/sys directory on your system, then the kernel source has not been installed. The easiest way to do this is by running sysinstall as root, choosing Configure, then Distributions, then src, then base and sys