Guide for installing Steam in chroot in Void Linux

void-llinux-steam-chroot.md

1. create chroot with xvoidstrap (see https://docs.voidlinux.org/config/containers-and-vms/chroot.html)

2. enter chroot with xchroot

3. install steam and all extra 32-bit dependencies and drivers (see /usr/share/doc/steam/README.voidlinux inside chroot after installing steam)

4. Since we're already in a separate namespace, bwrap cannot create another namespace, which causes it to fail, so we must make bwrap binary inside chroot setuid:

   chmod u+s /bin/bwrap
   

5. create new user in chroot:

   useradd -m -G audio,video gamer
   

6. exit chroot, e.g. with Ctrl+D

7. steam won't launch if we don't do 2 extra things:

   • make chroot dir itself a mount point: mount --bind $CHROOT $CHROOT
   • enter our chroot with unshare: unshare -m chroot $CHROOT

   Source: Gentoo wiki

   Explanation: With bare chroot, the Steam client does not run, complaining "Steam now requires user namespaces to be enabled." For this Steam tests if bwrap --bind / / true succeeds. (This requires bwrap is set setuid.) Internally bwrap calls pivot_root (2), of which conditions with "/" are not met under systemd. With unshare the namespace gets separated, and things work.

   So I've copied xchroot script from my system and changed 3 lines total (see comments): Save this script as xchroot-steam and use it in the next steps:

    #!/bin/sh -e
    # xchroot DIR [CMD...] - chroot into a Void (or other Linux) installation
   
    fail() {
    	printf '%s\n' "$1" >&2
    	exit 1
    }
   
    if [ "$(id -u)" -ne 0 ]; then
    	fail 'xchroot needs to run as root'
    fi
   
    CHROOT=$1; shift
   
    [ -d "$CHROOT" ] || fail 'not a directory'
    [ -d "$CHROOT/dev" ] || fail 'no /dev in chroot'
    [ -d "$CHROOT/proc" ] || fail 'no /proc in chroot'
    [ -d "$CHROOT/sys" ] || fail 'no /sys in chroot'
   
    mount --bind "$CHROOT" "$CHROOT" # ADDED: mount chroot dir onto itself
    for _fs in dev proc sys; do
    	mount --rbind "/$_fs" "$CHROOT/$_fs"
    	mount --make-rslave "$CHROOT/$_fs"
    done
   
    touch "$CHROOT/etc/resolv.conf"
    mount --bind /etc/resolv.conf "$CHROOT/etc/resolv.conf"
   
    cleanup() {
    	umount -R "$CHROOT/dev" "$CHROOT/proc" "$CHROOT/sys" "$CHROOT/etc/resolv.conf"
    	umount -l $CHROOT # ADDED: unmount chroot dir
    }
   
    trap cleanup EXIT INT
   
    if [ -x "$CHROOT/$SHELL" ]; then
    	INNER_SHELL="$SHELL"
    elif [ -x "$CHROOT/bin/bash" ]; then
    	INNER_SHELL="/bin/bash"
    else
    	INNER_SHELL="/bin/sh"
    fi
   
    printf "\033[1m=> Entering chroot $CHROOT\033[m\n"
    export PS1="[xchroot $CHROOT] $PS1"
    unshare -m chroot "$CHROOT" "${@:-$INNER_SHELL}" # CHANGED: use unshare for chroot
    STATUS=$?
    if [ $STATUS -ne 0 ]; then
    	printf "\033[1m=> Exited chroot $CHROOT\033[m\n"
    else
    	printf "\033[1m=> Exited chroot $CHROOT with status $STATUS\033[m\n"
    fi
    exit $STATUS
   

8. allow local connections to X server, by running this command in host system:

    xhost +localhost
   

   This is a potential security risk as any user could access the X server without authentication. To revoke access run xhost -localhost

9. launch steam with your new user:

   sudo bash ./xchroot-steam <chroot_dir> su -c 'steam' gamer
   

10. Repeat steps 8-9 to launch steam any time again.