I recently needed a up-to-date stage for a Via Epia 500 system. Since the hardware is very limited, and the processor is an i486 system (basicly a pentium pro without some missing features) i tried the uClibc stage. The update process of the somewhat out-of-date stage3 tarballs was really pain in the ass, so here is a guide to update the tarball to a recent portage/uclibc:

The Goal

  • A current portage (read: EAPI=2 capable)
  • A current udev
  • baselayout-2 and openrc
  • python 2.6
  • gcc 4.3+


Requirements

  • Some free disk space
  • Time, many time
  • Strong nerves
  • A lot of coffee


Step 1: Prepare the build environment

For this guide i use the following paths:

/mnt/work/chroots/gentoo32-i486-uclibc: The directory for the chroot

Now, lets get to work:

# change to working directory
cd /mnt/work/chroots/gentoo32-i486-uclibc
# fetch the most recent uclibc stage3 tarball
wget http://gentoo.j-schmitz.net/mirror/experimental/x86/embedded/stages/stage3-x86-uclibc-2008.0.tar.bz2
# Extract the tarball
tar xjpf stage3-x86-uclibc-2008.0.tar.bz2
# Remove the old tarball
rm stage3-x86-uclibc-2008.0.tar.bz2

# Mount some dirs for the chroot
mount -o bind /dev/ dev/
mount -t proc /proc/ proc/
mkdir usr/portage
mount -o bind /usr/portage/ usr/portage/

# now, chroot (remove linux32 if your host system is x86)
linux32 chroot . /bin/bash
env-update && source /etc/profile
export PS1="(uclibc-chroot) $PS1"


Step 2: Update the stage

The most important thing is to get a recent portage, since many ebuilds use EAPI-2. First, we have to update python. But python does not like the old gcc. So a newer gcc is required for python. But hey, gcc-4.3.4 fails due to a missing header file. So updating uclibc first.... 

# Unmask the latest uclibc
mkdir /etc/portage
echo "=sys-libs/uclibc-0.9.30.1-r1 ~x86" >> /etc/portage/package.keywords
emerge uclibc -av

# Now update gcc to 4.3.4
emerge gcc -va

# switch to the new gcc
gcc-config i386-gentoo-linux-uclibc-4.3.4
source /etc/profile
export PS1="(uclibc-chroot) $PS1"

# due to a bug in the python ebuild emerge python without docs
FEATURES="nodoc noinfo noman" emerge =dev-lang/python-2.4.6 -av

# update python to 2.5. You may have to update automake to 1.10.3. See bug #317705
# emerge -1va =sys-devel/automake-1.10.3
MAKEOPTS="-j1" emerge python -va
# run the python-updater and update all packages.
python-updater -p
# Make sure that you have updated all python libs before un-emerging the old python version!
emerge -C '<dev-lang/python-2.5'

# update python to 2.6.
emerge python -va
# run the python-updater
python-updater -p
# Make sure that you have updated all python libs before un-emerging the old python version!
emerge -C '<dev-lang/python-2.6'

# Finally, we can update portage
emerge portage -av1

# Emerge app-portage/gentoolkit to be able to run revdep-rebuild. You need an
# updated version of app-misc/realpath to get that work with uclibc (see
# http://bugs.gentoo.org/show_bug.cgi?id=300657)
# The new ebuild is in our overlay!
emerge -1va =app-misc/realpath-1.15-r1
emerge gentoolkit -va

# run a revdep-rebuild 
revdep-rebuild -i -vp

# Now, update all we have:
emerge --newuse --update --deep world -va

# remove the old gcc
emerge -Cav '<sys-devel/gcc-4.3.4'

# and build the whole bunch again
for x in linux-headers uclibc binutils-config binutils gcc-config gcc uclibc binutils gcc system world; do emerge -v1 $x; done

# clean up the environment
revdep-rebuild -i -vp
emerge --depclean -vp
revdep-rebuild -i -vp


Step 3: Install newer versions of openrc/baselayout

Now we have an up-to-date system, but we want a newer openrc and baselayout. Unmask these packages in /etc/portage/package.keywords: 

=sys-apps/baselayout-2.0.1 ~x86
=sys-apps/openrc-0.6.1-r1 ~x86

After that, emerge them and update the config files:

emerge openrc -av
dispatch-conf


Step 4: Cleanup and creating a new tarball

At last, clean up all the temp directories leave the chroot and create a new tarball:

rm -rf /var/tmp/portage/*
rm /tmp/*
# (leave the chroot)
umount dev/ proc/ usr/portage/

# create the new tarball
tar cjf /tmp/gentoo-x86-uclibc-20100429.tar.bz2 .


And thats it! The updated stage3-tarball can be downloaded here.

Update: udev needs some extra work to run with uclibc. See comment #7 and #8 of Bug #272199