Creating pre and post install scripts when updating kernel

[keremCozin]

Hello Gentoo community, I'm using gentoo-kernel-bin for my machine and I'm wondering if it's possible to create;
pre-install script to do;

Code: Select all

mount /boot

and then post-install script to do;

Code: Select all

grub-mkconfig -o /boot/grub/grub.cfg && umount /boot

for only gentoo-kernel-bin package?

If it's possible, where to put such scripts and how to create hooks on per-package basis,
I'm assuming it will be bash scripting.
I'm new to programming and such and thus I'd like learn how.

Thanks!

[Zucca]

Post-install is easy with scripts inside /etc/kernel/postinst.d directory.
See this topic.

Wiki mentions also /etc/kernel/preinst.d. I haven't used it but I would guess it works quite the same as postinst.d.

[keremCozin]

Thanks for the reply!
It's exactly what I was looking for.

[keremCozin]

The scripts in /etc/kernel/postinst.d directory works,
For /etc/kernel/preinst.d directory, I see we have /etc/kernel/install.d directory instead and that's apparently part of systemd. (I use systemd)
Neither of my scripts at /etc/kernel/preinst.d nor /etc/kernel/install.d did work. My system wasn't aware of the scripts in there.
Here what I did for my each folder, and for possible future reference;

At /etc/kernel/postinst.d I've created a file called 99-kernel.install

/etc/kernel/postinst.d/99-kernel.install

Code: Select all

#!/bin/env bash

grub-mkconfig -o /boot/grub/grub.cfg
sleep 2s
echo "Unmounting boot partition..."
umount /boot

chmod +x /etc/kernel/postinst.d/99-kernel.install

Also,
Tried both /etc/kernel/preinst.d and /etc/kernel/install.d directories and created the same file there so in this case,

/etc/kernel/install.d/99-kernel.install

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#!/bin/env bash

if mountpoint -q /boot
then
        echo "Boot partition is already mounted."
else
        echo "Mounting boot partition..."
        mount /boot
fi

chmod +x /etc/kernel/install.d/99-kernel.install

I'm looking for further instructions to make pre-install scripts work.
What can be done here, how can I write custom system hooks, is it possible, is it safe enough?
Thanks again!

[Zucca]

One way to achieve it is to go this route.

Try creating /etc/portage/env/sys-kernel/gentoo-kernel-bin/mount_boot.sh
Then put something like this in it:

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pre_pkg_setup() {
    if ! mountpoint -q /boot
    then
        mount /boot || die "Unable to mount /boot."
    fi
}

[keremCozin]

Thanks a lot! Gentoo linux is full of wonders =)

[Zucca]

intallkernel seems to be updated to support /etc/kernel/preinst.d now. I haven't tested it yet, but I recently did world update and I now have sys-kernel/installkernel-12.

More info on the wiki.

EDIT: systemd version of installkernel uses /etc/kernel/install.d.

[ZekeMorrin]

intallkernel seems to be updated to support /etc/kernel/preinst.d now. I haven't tested it yet, but I recently did world update and I now have sys-kernel/installkernel-12.

More info on the wiki.

EDIT: systemd version of installkernel uses /etc/kernel/install.d.

Wonderful, thanks for the heads up o7

[Nowa]

The scripts in /etc/kernel/postinst.d directory works,
For /etc/kernel/preinst.d directory, I see we have /etc/kernel/install.d directory instead and that's apparently part of systemd. (I use systemd)
Neither of my scripts at /etc/kernel/preinst.d nor /etc/kernel/install.d did work. My system wasn't aware of the scripts in there.
Here what I did for my each folder, and for possible future reference;

At /etc/kernel/postinst.d I've created a file called 99-kernel.install

/etc/kernel/postinst.d/99-kernel.install

Code: Select all

#!/bin/env bash

grub-mkconfig -o /boot/grub/grub.cfg
sleep 2s
echo "Unmounting boot partition..."
umount /boot

chmod +x /etc/kernel/postinst.d/99-kernel.install

Also,
Tried both /etc/kernel/preinst.d and /etc/kernel/install.d directories and created the same file there so in this case,

/etc/kernel/install.d/99-kernel.install

Code: Select all

#!/bin/env bash

if mountpoint -q /boot
then
        echo "Boot partition is already mounted."
else
        echo "Mounting boot partition..."
        mount /boot
fi

chmod +x /etc/kernel/install.d/99-kernel.install

I'm looking for further instructions to make pre-install scripts work.
What can be done here, how can I write custom system hooks, is it possible, is it safe enough?
Thanks again!

This should also work. I suspect the problem here is that your script has number 99, which means it is executed last. You want it executed first, specifically before the 90-*.install plugins which will actually do the copying to /boot.

Note that preinst.d and postinst.d are for installkernel[-systemd] whereas install.d is for installkernel[+systemd]. All plugins are executed after the install phase of the dist-kernels (i.e. gentoo-kernel) or when running make install. So pre and post refers here to before and after copying to /boot (which is what the main installkernel[-systemd] script will do). Whereas install.d is responsible for the whole chain, pre, copy to /boot, and post. Hope this clears this up.

Please do let me know if the wiki is unclear or confusing with respect to these plugins, you're not the first to have questions about this so I'd love to improve this wiki page where possible.