[gentoo-genkernel] Re: [RFC] Genkernel4 and Geninitramfs plan

[Sebastian Pipping]

On 09/09/2012 02:46 PM, Amadeusz Żołnowski wrote:
> As of my announcement post 20120901114601.4669.56900@localhost I
> present the plan for Genkernel4 and Geninitramfs.  I am waiting for
> your comments.
>
>
> Geninitramfs ~~~~~~~~~~~~
>
> [..]
>
> Geninitramfs is going to be extracted not earlier than Genkernel4
> is usable with Dracut to avoid synchronization work between
> Geninitramfs and Genkernel3.

I don't get that point, to be honest.  What is the problem and how
does pushing the spliut further way help about it?

One thing missing in the migration: does geninitramfs keep using
/etc/genkernel.conf ?  If so, how do we handle that?  if not, how do
we migrate smoothly?


> Genkernel4 ~~~~~~~~~~
>
> Genkernel4 is going to be rewritten from scratch in Bash4 and
> possibly with some help of Python if necessary.

Unlike with init scripts, there is no need for using shell scripting
here, right?  If so, let's stick to Python >=2.6 only, if just for
argparse alone.  Bash is one of genkernel's current issues in my opinion.


> Genkernel4 is going to:
>
> - build kernel, modules - build initramfs with Dracut or
> Geninitramfs (or possibly some other tool in the future -
> initramfs-tools maybe?) - install kernel, modules, firmware and
> initramfs - add/remove boot manager entries
>
>
> Genkernel4 workflow ~~~~~~~~~~~~~~~~~~~
>
>
> 01. List versions to (re)build
>
> a) local versions
>
> User with "list -l" argument lists versions installed in /usr/src
> and puts star next to the one to which /usr/src/linux symlink links
> to.
>
> b) remote versions
>
> User with "list -r <version-mask>" argument lists versions at
> kernel.org which could be downloaded and extracted to /usr/src.
> Why this option while gentoo-sources and others are installed by
> portage? Because some people prefer that portage doesn't register
> kernel sources in vdb.
>
> 02. Select version
>
> a) local
>
> User selects one of versions listed with "list -l" with arguments
> "select -l <version>/<position of version on the list>".  The
> check if sources still exist is done and the choice is remembered.
>
> b) remote
>
> User selects one of versions listed with "list -r" which doesn't
> exist in /usr/src with arguments "select -r <version>/<position of
> version on the list>".  It is checked if this particular version
> could be downloaded and the choice is remembered.

These are feature additions, if I am not mistaken.  Sounds good for later.


> 03. Fetch sources if user has chosen "remote"
>
> Tarball is fetched from kernel.org and extracted to /usr/src.
>
> 04. Setup sources
>
> Symlink to selected (and fetched) sources is set.
>
> 05. Prepare sources
>
> a) clean - make mrproper
>
> b) copy config
>
> Config file is copied from previous version (/proc/config.gz) or
> from location pointed by user.
>
> 06. Configure sources
>
> - make oldconfig/silentoldconfig/defconfig/... - make
> config/menuconfig/nconfig/... if user wants to
>
> 07. Build kernel and modules
>
> Runs "make" with CFLAGS, LDFLAGS, and JOBS given by user (in config
> file).

The question of building as root or non-root by our own Tobias
Klausmann pops into my mind:
<http://blog.i-no.de//archives/2012/07/index.html#e2012-07-04T19_28_32.txt>


> 08. Install modules and firmware
>
> - make modules_install firmware_install
>
> 09. Run module-rebuild rebuild if present
>
> It could also be a kind of hook defined in config file, for
> example:
>
> POST_MODULES_INSTALL_HOOK="module-rebuild rebuild"
>
> 10. Build initramfs
>
> An initramfs is going to be build either by Dracut or by
> Geninitramfs.  I'd like to avoid using command line options of
> Genkernel to pass to Geninitramfs or Dracut therefore Geninitramfs
> or Dracut config is going to be used only.

I see the point (when lookign from a maintenance perspective) but if
genkernel 4.x has the power to work with different kernel versions, at
least the kernel to operate with must be passed to the initramfs
generator, right?  I could imagine it would even make sense to
implement and forward all the options initially.


> 11. Rebuild kernel if initramfs is chosen to be built into kernel
>
> 12. Mount /boot if present in /etc/fstab
>
> 13. Install kernel
>
> - make install
>
> 14. Install initramfs
>
> Copies from image from tmp directory to /boot.
>
> 15. Update boot manager entries
>
> Adds appropriate entry to boot manager.
>
> 16. Umount /boot if it has been mounted in step 12.
>
>
> After successful reboot the cleanup could be made either by user
> command or automatically with some startup script.  Following items
> could be removed:
>
> 1. old trees in /lib/modules 2. old config, System.map and vmlinuz
> files from /boot 3. old initramfs image from /boot 4. old entries
> from boot manager 5. clean/mrproper old sources 6. (optionally) old
> sources if not managed by portage

Existing tool app-admin/eclean-kernel comes to my mind.  We should
check where re-use or duplication makes sense.

Best,



Sebastian