monochromatic

monochromatic blog: http://blog.z3bra.org
git clone git://z3bra.org/monochromatic
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commit 6bd9571517b7a95aea2500fe61e1a79302985dc3
parent b2a1c9c47ea60957f89dc6211f5b336c21f2a47f
Author: z3bra <willyatmailoodotorg>
Date:   Sun, 31 Jan 2016 12:15:11 +0000

New post: make your own distro

Diffstat:
2016/01/make-your-own-distro.txt | 77++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
config.mk | 5+++--
index.txt | 1+
3 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/2016/01/make-your-own-distro.txt b/2016/01/make-your-own-distro.txt @@ -8,6 +8,12 @@ So here is a fun project I'm working on: Making my own linux distro! I consider building a linux distribution from scratch to be one of the coolest things one could do with their computers. And I finally got into it! +I've been writing my "tales" in my +[journal](gopher://z3bra.org/0/distro/journal.txt). Be sure to read it for a +more "day-to-day" like approach. +This post is only meant to detail the tools used and the workflow I have when +I work on it. + First off all, I have never built an [LFS](https://linuxfromscratch.org) system, and will probably never do (their documentation is great though). @@ -46,11 +52,24 @@ I am using [pcc](http://pcc.ludd.ltu.se) as my complier of choice, and [musl](http://musl-libc.org) as my libc. To this day, I couldn't find a suitable replacement for GNU's binutils, but am -still looking forrward to elfutils and elftoolchain. +still looking forward to elfutils and elftoolchain. To make it easier to work with this toolchain, I decided to build a cross-compiler featuring both. I also had to create one using gcc, until I can figure out a patch for softwares that can't compile with pcc. +The script used to generate the cross-compiler can be found +[here](http://git.z3bra.org/cross/file/cross-gcc.html). + +In order to use it, add the path to the toolchain in your path. Calling +`x86_64-linux-musl-gcc` will automatically call libs/include from the cross +prefix. + +<video controls> + <source src='/vid/20160131-osdev-xcompiler.webm' type='video/webm'> +</video> +<span class='caption'>Using the cross-compiler to build a software statically +against musl libc.</span> + #### Package management toolchain There are a lot of them. But the most challenging one will be the one I'll write @@ -64,3 +83,59 @@ it follows the way the *BSD handle their own port-tree, while using mk(1) from plan9, which is, in my opinion, more predictable. For more information on mk, check the link [maintaining files on plan9 with mk](http://plan9.bell-labs.com/sys/doc/mk.html). + +The ports are available [here](http://git.z3bra.org/mkports/log.html). To build +a port, you need to configure the `config.mk` file to match your environment, and +run `mk <port>`. This will build all the deps required to build you port, and +install them under your cross-compilation root directory. +To clean the tree from this deps, run `mk clean`. The tarball will be packed in the +port directory of your tool, eg `pm/pm#1.0.tar.bz`. Theses file are suitable for +installation via [pm](http://git.z3bra.org/pm/log.html). + +<video controls> + <source src='/vid/20160131-osdev-mkports.webm' type='video/webm'> +</video> +<span class='caption'>Show casing the creation of a port within the mk port-tree +and building/installing it under a specific directory</span> + +#### Testing toolchain +To actually test the distro, you need a way to boot from it. I chose to use linux +containers (LXC) over traditionnal VMs (virtualbox, qemu) as I'm not playing with +different CPU architectures (yet!). +This way I can treat my distro as a simple chroot and modify it from outside in real +time. It also let me play with those containerization technologies I'm not +familiar with. + +The first thing to do is to install the packs under your chroot. For this purpose, I +chose `/ns/pm/rootfs`. After installing a few packs, you can fire up a container +using this directory as its root to check wether the distro boots, and if the tools +you installed work as expected. + +As of today, spawning gettys doesn't work. I'll need to figure out why, but otherwise, +it's been a pretty successful (and fun!) experience. + +<video controls> + <source src='/vid/20160131-osdev-containers.webm' type='video/webm'> +</video> +<span class='caption'>Demonstrating the whole testing process, from creating the +containers and saying "hello world!" from within this container</span> + +In the process, I learnt how to spawn containers "the hard way". Here is a quick +peak at it: + + ip link add veth0 type veth peer name eth0 + ip netns add foo + ip link set eth0 netns foo + ip netns exec foo ip addr add 192.168.0.100/24 dev eth0 broadcast + + ip netns exec foo ip link set eth0 up + ip netns exec foo ip route add default via 192.168.0.254 + brctl addif br0 veth0 + ip netns exec unshare -fpium --mount-proc env -i chroot /ns/pm/rootfs /sbin/init + +This is far from a final-run-everywhere solution of course, because you'll miss /dev +mounts, ttys and such, and won't be able to log within this container, or inject +processes in to it. + +But. + +That's neat. diff --git a/config.mk b/config.mk @@ -1,7 +1,7 @@ MD =/usr/bin/markdown NAME = monochromatic -PREFIX = /var/http/blog.z3bra.org +PREFIX = /var/www/blog.z3bra.org PAGES = index.html \ about.html \ @@ -29,7 +29,8 @@ PAGES = index.html \ 2015/04/the-wrong-sysadmin.html \ 2015/06/vomiting-colors.html \ 2015/08/cross-compiling-with-pcc-and-musl.html \ - 2015/08/install-alpine-at-onlinenet.html + 2015/08/install-alpine-at-onlinenet.html \ + 2016/01/make-your-own-distro.html FEEDS = rss/feed.xml EXTRA = css img vid data errors favicon.ico diff --git a/index.txt b/index.txt @@ -1,3 +1,4 @@ +* 0x001a - [Make your own distro](/2016/01/make-your-own-distro.html) * 0x0019 - [Install Alpine at online.net](/2015/08/install-alpine-at-onlinenet.html) * 0x0018 - [cross-compiling with PCC and musl](/2015/08/cross-compiling-with-pcc-and-musl.html) * 0x0017 - [Vomiting colors](/2015/06/vomiting-colors.html)