====== Input method in FreeBSD virtual terminal (Week1 & 2) ======

Date: 06/07-06/19

During these two weeks, I was preparing my kernel development environment, since this was the first time I tried to modify the freebsd kernel. Also I decided to take notes of the whole process of configuring the environment.

===== Environment Preparation =====

==== Building from Custom Source ====
=== Preparing Source ===
I forked %%FreeBSD%% source code on github: https://github.com/Cycatz/freebsd-src

And clone the project into ''%%/usr/src/%%''.
But ''%%/usr/src%%'' is a zfs dataset, we can not backup the old ''%%/usr/src%%'' by simply renaming it.
So I copied it into other directory and remove all old files in ''%%usr/src%%'' then clone the source code.

<code>
cp /usr/src /usr/src.bak
cd /usr/src
rm -rf ./* ./.*
</code>

Download the source code:

<code>
git remote add origin https://github.com/Cycatz/freebsd-src
git fetch origin
</code>

=== Building and Installing Custom Source ===

To build the custom kernel, copy the //GENERIC// kernel config file first:

<code>
cp /usr/src/sys/amd64/conf/GENERIC /root/MYKERNEL
cd /usr/src/sys/amd64/conf
ln -s /root/MYKERNEL .
</code>

But actually I didn't modify any configurations from GENERIC kernel config except for the //ident// column.

<code>
ident MYKERNEL
</code>

Now we are ready to build world and kernel:

First we need to install ''%%bear%%'' to index kernel source and generate ''%%compile_commands.json%%'' for LSP

<code>
pkg install py37-bear
</code>

Now we can build and install them:

<code>
cd /usr/src
make -DNO_CLEAN -j 8 buildworld
bear make -DNO_CLEAN -j 8 buildkernel KERNCONF=MYKERNEL
make installworld
make installkernel KERNCONF=MYKERNEL
etcupdate
reboot
</code>

After rebooting, use ''%%uname -a%%'' to check if our system version and the kernel profile are correct:

The results:

<code>
FreeBSD vt.staque.xyz 14.0-CURRENT FreeBSD 14.0-CURRENT #1 tmp-n248823-ced2dcadccfc-dirty: Fri Aug 20 21:32:02 CST 2021     root@vt.staque.xyz:/usr/obj/usr/src/amd64.amd64/sys/MYKERNEL  amd64
</code>

=== Reference ===
  * Ch 8. Configuring the %%FreeBSD%% Kernel: https://docs.freebsd.org/en/books/handbook/kernelconfig/ 
  * Ch 24. Updating and Upgrading %%FreeBSD%%: https://docs.freebsd.org/en/books/handbook/cutting-edge/#freebsdupdate-portsrebuild

===== Developing on FreeBSD =====

Install clangd:

<code>
pkg install llvm12
</code>

Make an alias for clangd12:

<code>
ln -s clangd12 clangd
</code>