Gentoo on Raspberry Pi
Gentoo, being a source distribution, is not the best fit for a Raspberry Pi.
Compiling all the packages takes a lot of time and is not the best for your
SD Card. To counter this problem we can use distcc and crossdev but I
would prefer to use crossdev and the binary packages option for my Pi.
Lets get started... I am going to create packages for nano, it is a relatively simple but has a few dependencies.
Setup crossdev and Custom Repository
Firsly emerge sys-devel/crossdev and create the required directories and
files.
emerge sys-devel/crossdev
mkdir -p /usr/local/portage/crossdev/{profiles,metadata}
echo 'crossdev' > /usr/local/portage/crossdev/profiles/repo_name
echo 'masters = gentoo' > /usr/local/portage/crossdev/metadata/layout.conf
chown -R portage:portage /usr/local/portage/crossdev
Tell portage to use the gentoo repository and as the fallback and crossdev
will create ebuilds in /usr/local/portage/crossdev for the generated
packages. Below is /etc/portage/repos.conf/crossdev.conf (if you don't
have /etc/portage/repos.conf/ you should create it):
[crossdev]
priority = 9999
masters = gentoo
auto-sync = no
location = /usr/local/portage/crossdev
Initialise the repository:
crossdev -t armv7a-hardfloat-linux-gnueabi --stable --init-target -oO /usr/local/portage/crossdev
Change the use flags to disable some use flags (I am not sure if this is required...):
echo "cross-armv7a-hardfloat-linux-gnueabi/gcc -sanitize -vtv" >> /etc/portage/package.use/crossdev
Create the toolchain:
crossdev -t armv7a-hardfloat-linux-gnueabi --stable -oO /usr/local/portage/crossdev
Cool! with that you should be able to compile a very simple hello world C programme with your ARM cross compiler. If you cannot then you should get this working before continuing. See Appendix A for how to do this.
Configure the make.profile and make.conf
Check in /usr/armv7a-hardfloat-linux-gnueabi/etc/portage/make.conf and
if I were you I would put buildpkg in your features line, it is probably
already there, mine looks like this:
FEATURES="-collision-protect sandbox buildpkg noman noinfo nodoc"
You can build packages on a per emerge basis by specifying it at emerge
time with --buildpkg but you might forget ;-).
These steps set the correct profile, by default you are probably using
the embedded profile which will not work to emerge stuff for your Pi:
cd /usr/armv7a-hardfloat-linux-gnueabi
ln -s /usr/portage/profiles/default/linux/arm/13.0/armv7a/ etc/portage/make.profile
Emerge nano
Now the fun part emerging nano:
armv7a-hardfloat-linux-gnueabi-emerge app-editors/nano
This on my system portage pulled in 5 packages:
sys-libs/zlib-1.2.11
sys-libs/ncurses-6.0-r1:0/6
virtual/libintl-0-r2
sys-apps/file-5.30
app-editors/nano-2.7.5
This may take some time, you can always make it faster by changing the
MAKEOPTS="-j4" in /usr/armv7a-hardfloat-linux-gnueabi/etc/portage/make.conf
depending on your system.
Once complete the emerge should have installed executables and generated some binary packages in the packages directory:
/usr/armv7a-hardfloat-linux-gnueabi/packages/
Now you can install them on your Pi.
Installing a Binary Package
Now it is time to get the package on your Raspberry Pi. For this I would recommend configuring a binary package host.
I plan on configuring a public one some time soon hosted on this server to use it please look at my binary package host page. Configuring a binary package host is a little out of scope please see the Gentoo Wiki.
To get the packages on your Pi copy them from the armv7a-hardfloat-linux-gnueabi/packages/
directory to the /usr/portage/packages/ directory (or wherever you
configured your PKGDIR). The structure is important!
Now you can try and emerge nano, make sure your portage tree is at least as up to date as the tree on the generating machine.
emerge -pv --usepkgonly app-editors/nano
The output looks like this (with pretty colours):
[binary U ~] app-editors/nano-2.7.5::gentoo [2.5.3::gentoo] USE="magic ncurses nls spell unicode -debug -justify -minimal -slang -static" 0 KiB
The only thing I should say now is be careful of USE flags and KEYWORDS.
Of course remove the -pv to actually install the package.
nano --version
GNU nano, version 2.5.3
(C) 1999..2016 Free Software Foundation, Inc.
Email: nano@nano-editor.org Web: http://www.nano-editor.org/
Compiled options: --disable-justify --disable-wrapping-as-root --enable-utf8
After emerge:
GNU nano, version 2.7.5
(C) 1999..2016 Free Software Foundation, Inc.
(C) 2014..2017 the contributors to nano
Email: nano@nano-editor.org Web: https://nano-editor.org/
Compiled options: --disable-justify --disable-wrapping-as-root --enable-utf8
I bet you were surprised weren't you!?
Appendix A
Writing and Compiling a simple programme for Raspberry Pi 2. Create main.c
with the following content.
#include <stdio.h>
int main(int argc, char * argv[]) {
fprintf(stdout, "Hello World!");
}
Then compile it like this:
armv7a-hardfloat-linux-gnueabi-gcc -o main main.c
And try to execute the resulting file on your Raspberry Pi.
References
- olsonbg/crossdev-gentoo good information but a little broken.
- Custom Repostory
see the section on
crossdev