Install bundled 32-bit system in 64-bit system

Make the i686 Chroot

tl;dr version

Setup

For those wanting a single copy/paste:

export LOCATION=/opt/arch32 # more flexibility here if users wish an alternative location for the chroot
mkdir $LOCATION
sed -e 's/\$arch/i686/g' /etc/pacman.d/mirrorlist > $LOCATION/mirrorlist
sed -e "s@/etc/pacman.d/mirrorlist@$LOCATION/mirrorlist@g" -e '/Architecture/ s,auto,i686,'  /etc/pacman.conf > $LOCATION/pacman.conf
mkdir -p $LOCATION/var/{cache/pacman/pkg,lib/pacman}
pacman --root $LOCATION --cachedir $LOCATION/var/cache/pacman/pkg --config $LOCATION/pacman.conf -Sy
pacman --root $LOCATION --cachedir $LOCATION/var/cache/pacman/pkg --config $LOCATION/pacman.conf -S base base-devel sudo
mv -f $LOCATION/mirrorlist $LOCATION/etc/pacman.d
rm -f $LOCATION/pacman.conf
sed -i 's/CheckSpace/#CheckSpace/' $LOCATION/etc/pacman.conf
cd $LOCATION/etc
cp /etc/passwd* .
cp /etc/shadow* .
cp /etc/group* .
cp /etc/sudoers .
cp /etc/resolv.conf .
cp /etc/localtime .
cp /etc/locale.gen .
cp /etc/profile.d/locale.sh profile.d
cp /etc/vimrc .
cp /etc/mtab .
cp /etc/inputrc .

Now skip to the daemon section.

Install the Base 32-bit System

1. Create the directory:

mkdir /opt/arch32

2. Generate temporary pacman configuration files for chroot:

sed -e 's/\$arch/i686/g' /etc/pacman.d/mirrorlist > /opt/arch32/mirrorlist
sed -e 's@/etc/pacman.d/mirrorlist@/opt/arch32/mirrorlist@g' -e '/Architecture/ s,auto,i686,'  /etc/pacman.conf > /opt/arch32/pacman.conf

• These files would conflict with the normal pacman files, which will be installed in the later steps.
• For this reason they must be put into a temporary location (/opt/arch32 is used here).
• Remember to delete/comment the multilib repo, if you have enable it, in the /opt/arch32/pacman.conf file

3. Create the directory:

mkdir -p /opt/arch32/var/{cache/pacman/pkg,lib/pacman}

4. Sync pacman:

pacman --root /opt/arch32 --cachedir /opt/arch32/var/cache/pacman/pkg --config /opt/arch32/pacman.conf -Sy

5. Install the base and optionally base-devel groups:

pacman --root /opt/arch32 --cachedir /opt/arch32/var/cache/pacman/pkg --config /opt/arch32/pacman.conf -S base base-devel

Optionally add your favorite text editor and distcc if you plan to compile within the chroot with other machines:

pacman --root /opt/arch32 --cachedir /opt/arch32/var/cache/pacman/pkg --config /opt/arch32/pacman.conf -S base base-devel sudo vim distcc

Optionally move the pacman mirror list into place:

mv /opt/arch32/mirrorlist /opt/arch32/etc/pacman.d

Configuration files

Key configuration files should be copied over:

cd /opt/arch32/etc

cp /etc/passwd* .
cp /etc/shadow* .
cp /etc/group* .
cp /etc/sudoers .
cp /etc/resolv.conf .
cp /etc/localtime .
cp /etc/locale.gen .
cp /etc/profile.d/locale.sh profile.d
cp /etc/vimrc .
cp /etc/mtab .
cp /etc/inputrc .

Be sure to include the "." character!

Remember to define the correct the number of MAKEFLAGS and other vars in /opt/arch32/etc/makepkg.conf before attempting to build.

Create an Arch32 Daemon Script and Systemd Service

/etc/systemd/system/arch32.service

[Unit]
Description=32-bit chroot

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/local/bin/arch32 start
ExecStop=/usr/local/bin/arch32 stop

[Install]
WantedBy=multi-user.target

/usr/local/bin/arch32

#!/bin/bash

MOUNTPOINT=/opt/arch32
PIDFILE=/run/arch32

# Leave this blank if not using distccd from within the chroot.
USEDISTCC=
DISTCC_SUBNET='192.168.0.0/24'

start_distccd() {
  [[ ! -L $MOUNTPOINT/usr/bin/distccd-chroot ]] && ln -s /usr/bin/distccd $MOUNTPOINT/usr/bin/distccd-chroot
  DISTCC_ARGS="--user nobody --allow $DISTCC_SUBNET --port 3692 --log-level warning --log-file /tmp/distccd-i686.log"

  if [[ -z "$(pgrep distccd-chroot)" ]]; then
    linux32 chroot $MOUNTPOINT /bin/bash -c "/usr/bin/distccd-chroot --daemon ${DISTCC_ARGS}"
  else
    echo "/usr/bin/distccd-chroot seems to be running so doing nothing!"
  fi
}

stop_distccd() {
  if [[ -n "$(pgrep distccd-chroot)" ]]; then
    linux32 chroot $MOUNTPOINT /bin/bash -c "pkill -SIGTERM distccd-chroot"
  else
    echo "/usr/bin/distccd-chroot does NOT seems to be running so doing nothing!"
  fi
}

case $1 in
  start)
    # Only relevant for users with an arch32 chroot on a separate partition.
    # Edit to fit your system and take note of the corresponding unmount option in the stop function!
    # mountpoint -q $MOUNTPOINT || mount LABEL="arch32" $MOUNTPOINT

    dirs=(/tmp /dev /dev/pts /home)
    for d in "${dirs[@]}"; do
      mount -o bind $d $MOUNTPOINT$d
    done

    mount -t proc none $MOUNTPOINT/proc
    mount -t sysfs none $MOUNTPOINT/sys
    touch $PIDFILE
    [[ -n "$USEDISTCC" ]] && start_distccd
    ;;
  stop)
    dirs=(/home /dev/pts /dev /tmp)
    [[ -n "$USEDISTCC" ]] && stop_distccd
    umount $MOUNTPOINT/{sys,proc}
    for d in "${dirs[@]}"; do
      umount -l "$MOUNTPOINT$d"
    done
    # Only relevant for users with an arch32 chroot on a separate partition.
    # umount -l $MOUNTPOINT
    rm -f $PIDFILE
    ;;
  *)
    echo "usage: $0 (start|stop)"
    exit 1
esac

# vim:set ts=2 sw=2 et:

Be sure to make the init script executable:

# chmod +x /usr/local/bin/arch32

Enable the service as any other systemd service.

Configure the new system

Configure the chroot

Chroot into the new system:

/usr/local/bin/arch32 start
xhost +SI:localuser:usernametogiveaccesstogoeshere 
chroot /opt/arch32

It is recommended to use a custom bash prompt inside the 32-bit chroot installation in order to differentiate from the regular system. You can, for example, add a ARCH32 string to the PS1 variable defined in ~/.bashrc. In fact, the default Debian .bashrc prompt string contains appropriate logic to report whether the working directory is within a chroot.

First-time Setup

Fix possible locale issues:

/usr/sbin/locale-gen

Initialize pacman:

sed -i 's/CheckSpace/#CheckSpace/' /etc/pacman.conf
pacman-key --init
pacman-key --populate archlinux

Install Needed Packages

Install the needed packages including apps, fonts, etc. for example:

pacman -S firefox
pacman -S flashplugin

Regain Space (Optional)

Warning: This cleanup is for the 32-bit root environment and must then be done inside it NOT the native 64-bit environment!

The following shows recommended packages for removal:

pacman -Rd linux mkinitcpio dhcpcd ppp xfsprogs reiserfsprogs jfsutils logrotate lvm2 pcmciautils netcfg heirloom-mailx iputils iproute2 man-pages mdadm inetutils man-db cronie vi

Also consider regularly clearing out pacman's cache:

pacman -Scc

Install and Configure Schroot

Install "schroot" to the native 64-bit installation:

pacman -S schroot

Edit /etc/schroot/schroot.conf, and create an [Arch32] section.

[Arch32]
type=directory
profile=arch32
description=Arch32
directory=/opt/arch32
users=user1,user2,user3
groups=users
root-groups=root
personality=linux32
aliases=32,default

Optionally edit /etc/schroot/arch32/mount to match the mounts created within /usr/local/bin/arch32.

Using Schroot to run a 32-bit application

The general syntax for calling an application inside the chroot is:

schroot -p -- htop

In this example, htop is called from within the 32-bit environment.

Troubleshooting

Compilation and installing

Ensure the desired options are set in the local /etc/makepkg.conf.

Some packages may require a --host flag be added to the ./configure script in the PKBUILD:

./configure --host="i686-pc-linux" ...

This is the case when the build makes use of values (for example, the output of the uname command) inherited from your base system.

You may need to give users write access to your chroot's /dev/null to stop some scripts from failing:

chmod 666 /dev/null

Video issues

If you get:

X Error of failed request: BadLength (poly request too large or internal Xlib length error)

while trying to run an application that requires video acceleration, make sure you have installed appropriate video drivers in your chroot. For example,

pacman -S nvidia

Sound in flash (youtube, etc.)

To get sound from the flash player in Firefox, open a terminal and chroot inside the 32-bit system:

chroot /opt/arch32

From there, install alsa-oss:

pacman -S alsa-oss

Then type:

export FIREFOX_DSP="aoss"

Every chroot into the 32-bit system will require this export command to be entered so it may be best to incorporate it into a script.

Finally, launch Firefox.

For Wine this works the same way. The package alsa-oss will also install the alsa libs required by Wine to output sound.

Tips and tricks

Java in a chroot

See Java for installation instructions.

After installing, adjust the path to get Java working:

export PATH="/opt/java/bin/:$PATH"

arch32-light

Xyne has created a package that installs a minimalist 32-bit chroot as described above. More information can be found on the forum and on the project page.

Allowing 32-bit applications access to 64-bit Pulseaudio

Add these lines in /usr/local/bin/arch32, before the daemon is started:

mount --bind /var/run /opt/arch32/var/run
mount --bind /var/lib/dbus /opt/arch32/var/lib/dbus

And before the daemon is stopped:

umount /opt/arch32/var/run
umount /opt/arch32/var/lib/dbus

More information is available at the Pulseaudio article, especially the section on Pulseaudio from within a chroot.

Enabling sound in Firefox

Open a text editor and save the following in /usr/bin/firefox32 as root:

#!/bin/sh
schroot -p firefox $1;export FIREFOX_DSP="aoss"

Make it executable:

sudo chmod +x /usr/bin/firefox32

Now you can make an alias for Firefox, if desired:

alias firefox="firefox32"

Add this to the end of file ~/.bashrc and source it to enable its usage. Or you can just change all your desktop environment's launchers to firefox32 if you still want 64-bit Firefox to be available.

Enabling 3D acceleration

In case you want to run any 32 bit application under your chroot with 3D acceleration (e.g. WINE, native 32 bit games) you simply need to install the corresponding libs as under your "native" arch.

For an ATI card using the radeon driver this could be:

pacman -S xf86-video-ati libgl ati-dri

For more informations on how to set up your graphic adapter refer to:

ATI

Intel

NVIDIA

Your can easily check if you have 3D rendering within the 32 bit chroot by installing mesa-demos and running the following command:

 glxinfo | grep renderer

If you have no 3D acceleration you will get some output like this:

 [joe@arch64]$ OpenGL renderer string: Software Rasterizer

If 3D acceleration is enabled you will get a message like this:

 [joe@arch64]$ OpenGL renderer string: Mesa DRI R600 (RV730 9490) 20090101 x86/MMX+/3DNow!+/SSE2 TCL DRI2

Script for wine

In order to compile wine, you need a 32-bit system installed. Compiling wine is needed for applying patches in order to get PulseAudio working. See also wine-hacks from AUR.

Add the following alias to ~/.bashrc:

alias wine='schroot -pqd "$(pwd)" -- wine'

The -q switch makes schroot operate in quiet mode, so it works like "regular" wine does. Also note that If you still use dchroot instead of schroot, you should use switch -d instead of -s.