Install bundled 32-bit system in 64-bit system - ArchWiki

# Install bundled 32-bit system in 64-bit system

This article presents one way of running 32-bit applications, which may be of use to those who do not wish to install the lib32-* libraries from the multilib repository and instead prefer to isolate 32bit applications. The approach involves creating a "chroot jail" to handle 32-bit apps.

Tip: Xyne has created a package that installs a minimalist 32-bit chroot as described below. See [1] and [2] for details.

## Installation

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 enabled 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

### Settings

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.

### Daemon 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() {
      echo 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() {
      echo 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=(/home)
        for d in "${dirs[@]}"; do
          mount -v -o bind $d ${MOUNTPOINT}${d}
        done

        mount -v -t devtmpfs dev "${MOUNTPOINT}/dev"
        mount -v -t devpts devpts "${MOUNTPOINT}/dev/pts"
        mount -v -t tmpfs devshm "${MOUNTPOINT}/dev/shm"
        mount -v -t proc proc "${MOUNTPOINT}/proc"
        mount -v -t tmpfs run "${MOUNTPOINT}/run"
        mount -v -t sysfs sys "${MOUNTPOINT}/sys"
        mount -v -t tmpfs tmp "${MOUNTPOINT}/tmp"

        touch ${PIDFILE}

        if [ -n "$USEDISTCC" ] ; then
           start_distccd
        fi
        ;;
      stop)
        if [ -n "$USEDISTCC" ] ; then
           stop_distccd
        fi

        dirs=(/tmp /sys /run /proc /dev/shm /dev/pts /dev /home)
        for d in "${dirs[@]}"; do
          umount -v -l "${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

Be sure to make the init script executable:

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

Enable the service as any other systemd service.

## Configuration

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 problems:

    /usr/sbin/locale-gen

Initialize pacman:

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

### Necessary packages

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

    pacman -S firefox
    pacman -S flashplugin

### Regain space (Optional)

Warning: This cleanup belongs insde the 32-bit root environment, NOT the native 64-bit environment!

The following shows recommended packages for removal:

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

Also consider regularly clearing out pacman's cache:

    pacman -Scc

## Schroot

Install schroot to the native 64-bit installation:

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 problems

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

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. After installation, adjust the path:

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

### Allow 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

See PulseAudio from within a chroot for details

### Sound in Firefox

Create `/usr/bin/firefox32` as root:

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

Make it executable:

    # chmod +x /usr/bin/firefox32

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

    alias firefox="firefox32"

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

### 3D acceleration

You need to install the corresponding package under your "native" arch for 3D support.

For information on how to set up your graphic adapter refer to:

- ATI
- Intel
- NVIDIA

### WINE

This article or section is out of date.

Reason: The wine-hacks package does not exist anymore. (Discuss)

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`.

### Printing

For accessing CUPS printers intalled in the base system from the chroot environment, see CUPS#Installing CUPS in a 32-bit chroot environment.

Category:

- Getting and installing Arch