gentoo on The Programmer's Chest

Upgrading Gentoo kernel automatically

Sun, 01 Oct 2017 12:35:09 +0100

I’ve been using Gentoo for a few years now. And every time a new kernel version went out, I ended visiting Gentoo’s wiki page Kernel/Upgrade and following its steps to upgrade the kernel.

But I thought it would be better to automate the process, so I wrote a simple bash script that from now on will do the work for me. It may be useful for other Gentoo users:

#!/usr/bin/env bash

## Upgrade gentoo kernel

# The first and only argument must be the folder name of the new kernel.

# Stop script when an error occurs
set -o errexit
set -o pipefail
set -o nounset
# For debugging purposes
set -o xtrace

readonly kernel_path='/usr/src/'

_usage () {
    local script_name="$0"
    echo "Usage: $0 <newkernelfolder>"
}

_main () {
    echo "Backing up old kernel..."
    cd "${kernel_path}/linux/"
    cp .config ~/kernel-config-"$(uname -r)"
    echo "Copying old configuration..."
    cp /usr/src/linux/.config /tmp/.config
    echo "Setting new kernel as default..."
    #ln -sf /usr/src/"$1" /usr/src/linux
    cp /tmp/.config /usr/src/linux/
    eselect kernel set 2
    cd /usr/src/linux/
    echo "Building..."
    make -j4 olddefconfig
    make -j4 modules_prepare
    make modules_install
    emerge --ask @module-rebuild
    make -j4
    make install
    echo "Please, update your EFI entry: cp /boot/vmlinuz-*-gentoo /boot/efi/boot/bootx64.efi"
}


if [[ $# -eq 1 ]]
then
    _main $1
else
    _usage
fi

To use it, simply write:

$ sudo ./updatekernel.sh linux-4.12.12-gentoo

Where linux-4.12.12-gentoo is the name of the new kernel.

Contributions are welcome, because there is still room for improvement, you can check the script in my Dotfiles repository.

After writing the script, I saw portage already have hooks for execute actions when new ebuilds are downloaded, but when I tried it I realized that the .config from my previous kernel was not being picked up. I am sure there is a way to tell portage hooks to use the previous config, but since I’ve already wrote the script, I decided to use it.

Hope you find the script useful!

Update

I posted this script on the Gentoo subreddit /r/Gentoo and it has received a lot of comments. Some redditors had posted its own ways to update a kernel automatically, here are some of them:

htay6r7ce script:

eselect kernel list
eselect kernel set #

# Use current kernel config and store copy
gunzip /proc/config.gz -c > /root/config; cp /root/config /root/config-$(uname -r)

#  Optionally change module settings in the config file, or use --menuconfig
#  with genkernel.
genkernel --makeopts=-j9 --splash --kernel-config=/root/config all

# Update packages with kernel modules
emerge -1 @module-rebuild

# Cleanup old files
for name in $(ls /lib/modules/ | sort -V | head -n -3); do
  rm -rf /boot/{initramfs,kernel,System.map}-genkernel-x86_64-${name:?}
  rm -rf /lib/modules/${name:?}
done

# Update boot config file
grub-mkconfig -o /boot/grub/grub.cfg

Btirooh script its repo jeekkd/gentoo-kernel-build.
KernelKunt has its script on github: t4nki/kupdate
sQu1rr kernel update on github gists.
htay6r7ce use the following script:

eselect kernel list
eselect kernel set #

# Use current kernel config and store copy
gunzip /proc/config.gz -c > /root/config; cp /root/config /root/config-$(uname -r)

#  Optionally change module settings in the config file, or use --menuconfig
#  with genkernel.
genkernel --makeopts=-j9 --splash --kernel-config=/root/config all

# Update packages with kernel modules
emerge -1 @module-rebuild

# Cleanup old files
for name in $(ls /lib/modules/ | sort -V | head -n -3); do
  rm -rf /boot/{initramfs,kernel,System.map}-genkernel-x86_64-${name:?}
  rm -rf /lib/modules/${name:?}
done

# Update boot config file
grub-mkconfig -o /boot/grub/grub.cfg

All of them are far more elaborate than mine, so I will try to use them and improve mine.

How to remove slotted packages in gentoo

Sat, 04 Feb 2017 12:53:37 +0100

Recently I had a problem trying to remove slotted packages in Gentoo, here is how I did it.

First use equery list <pkg> to list package matching PKG:

$ equery list emacs
 * Searching for emacs ...
[IP-] [  ] app-editors/emacs-24.5-r3:24
[IP-] [  ] app-editors/emacs-25.1:25

There are two emacs packages, slotted in :24 and :25, respectively. In order to remove the older version, execute:

$ sudo emerge -C emacs-24.5-r3:24
Password:
 * This action can remove important packages! In order to be safer, use
 * `emerge -pv --depclean <atom>` to check for reverse dependencies before
 * removing packages.

 app-editors/emacs
    selected: 24.5-r3
   protected: none
     omitted: 25.1

All selected packages: =app-editors/emacs-24.5-r3

>>> 'Selected' packages are slated for removal.
>>> 'Protected' and 'omitted' packages will not be removed.

>>> Waiting 5 seconds before starting...
>>> (Control-C to abort)...
>>> Unmerging in: 5 4 3 2 1
>>> Unmerging (1 of 1) app-editors/emacs-24.5-r3...
 * Regenerating site-gentoo.el for GNU Emacs (postrm) ...
[ ok ]
 * ... 4 site initialisation files included.

 * Regenerating GNU info directory index...
 * Processed 140 info files.

After removing the package, check what packages depended on it:

 $ equery depends emacs-24.5-r3:24
 * These packages depend on emacs-24.5-r3:24:
app-emacs/emacs-common-gentoo-1.5 (virtual/emacs)
app-emacs/markdown-mode-2.1 (>=virtual/emacs-23)
app-emacs/quilt-el-0.48.0 (>=virtual/emacs-23)
app-emacs/scala-mode-2.10.3 (>=virtual/emacs-23)
dev-python/cython-0.24.1 (emacs ? virtual/emacs)
dev-scheme/guile-1.8.8-r3 (emacs ? virtual/emacs)
dev-util/cmake-3.6.3 (emacs ? virtual/emacs)
dev-util/desktop-file-utils-0.23 (emacs ? virtual/emacs)
dev-util/ninja-1.6.0 (emacs ? virtual/emacs)
dev-vcs/git-2.10.2 (emacs ? virtual/emacs)
net-dns/libidn-1.33 (emacs ? virtual/emacs)
virtual/editor-0 (app-editors/emacs)
virtual/emacs-24 (app-editors/emacs:24)

The last step:

sudo emerge --update --deep --with-bdeps=y --newuse -atv @world

References

Gentoo Forums | Remove Slotted Packages

How to Change Portage Folders to Other Location in Gentoo

Wed, 17 Aug 2016 08:06:32 +0000

Recently I had a problem with portage and its tmp directory in /var/tmp/portage in Gentoo. I had no space left in the disk, the error message was:

There is NOT at least 10 GiB disk space at "/var/tmp/portage

So first I decided to change all the portage files to my secondary hard disk drive, here is how to change portage folders to a new location.

Changing /etc/portage/make.conf file

Suppose the new directory is /home/hkr/ssd2/portage.

The first thing to to is update the environment variables PORTDIR, DISTDIR and PKGDIR to point to the new location, so in the file make.conf we need to write:

PORTDIR="/home/hkr/ssd2/portage"
DISTDIR="${PORTDIR}/distfiles"
PKGDIR="${PORTDIR}/packages"

Syncing portage tree

Now that we had updated the variables, we need to sync portage:

emerge --sync

After that, portage now knows about the new location, but there is one more thing to do.

Symlinking make.profile to the new location

After syncing portage, one last thing to do is symlinking make.profile to the new location, previously it was a symlink to /usr/portage/profiles/default/linux/amd64/13.0/desktop/, but we need to update it to the new location. Here is how:

ln -s /home/hkr/ssd2/portage/profiles/default/linux/amd64/13.0/desktop /etc/portage/make.profile

Now everything is right and we have changed the portage location and get rid of the space problems.

Changing only the tmp directory (/var/tmp/portage)

After doing the previous steps, I realized that it would be a better option to only change the location of the tmp portage directory (by default /var/tmp/portage), that was the original problem, because I did not had enough space left there. So a better option would be leave make.conf as we had it previously, and only add a new variable:

PORTAGE_TMPDIR="/home/hkr/ssd2/"

Hope it helps!.

References

Can't Update to Firefox 48 in Gentoo, NSS Version Too Old

Thu, 04 Aug 2016 09:05:17 +0000

Today, when I check for updates in my Gentoo machine, the new Firefox 48 was released. But when I tried to update I kept getting this error:

configure: error: you don't have NSS installed or your version is too old

I tried to enable the NSS USE flag, but did not work, so I went to the Gentoo forums and asked there. After a few minutes they answered me, it is a current bug that need to be solved. But fortunately there is a workaround until the bug is fixed:

echo "=dev-libs/nss-3.24 ~amd64" >> /etc/portage/package.accept_keywords
emerge -u nss
emerge =www-client/firefox-48.0

Executing the above in a terminal as root will force portage to install the version 3.24 of NSS, and then firefox will not complain about the old version.

Once firefox 48 is installed, we can enjoy the new multiprocessing feature.

Thanks to fedeliallalinea for solving me the problem in the forums!