msrutil

About

msrutil is a work-in-progress MacOS kernel extension (or KEXT) designed to access kernel-specific data structures anad other information that is privy to solely the kernel.

This was designed to help with another project focusing on displaying low-level computer stats and information.

Usage

Setup

0. Are you on a MacOS version greater than 10.14? I'm sorry to say that this project is not for you. With the Mojave update, Apple removed partial disabling of SIP (i.e. only allowing KEXTs but leaving all the other security features intact), already making this process more difficult. However Catalina has begun phasing out KEXTs entirely.
1. Reboot your computer and hold CMD-R while it restarts to boot into Recovery Mode.
2. While in Recovery Mode, navigate to the terminal through the top menu.
3. Run csrutil enable --without kext to allow unsigned KEXTs to run on your computer. If you are on 10.14, you will have to fully disable SIP by running csrutil disable.
4. Reboot your computer oncemore.

Loading

1. Run xcodebuild -configuration Debug to build the KEXT.
2. Navigate to the KEXT executable (likely at ./build/Debug/). Check the modified date, delete it if it doesn't match, then re-build.
3. Run sudo cp -R msrutil.kext /private/tmp && cd /private/tmp to create a copy of the KEXT executable that you own, allowing you to load it.
4. Run sudo kextload msrutil.kext to load the KEXT.
5. Check the system logs (either through Console.app or a UNIX command) and if you see the message "msrutil successfully loaded", you've done it!
   • You can double-check that the KEXT is running with kextstat.
6. Unload the kext with sudo kextunload msrutil.kext and once again check the system logs for the message "msrutil successfully unloaded".

Calling

As of now communicating with the kernel extension does not work.