A useful script for working with Gentoo in chroot environment.

chroot.sh

#!/bin/bash

set -e -o pipefail

BASEDIR=$(dirname "$(readlink -f $0)")

if ! grep -q "${BASEDIR}/proc" /proc/mounts; then
        mount --types proc /proc "${BASEDIR}/proc"
fi

if ! grep -q "${BASEDIR}/sys" /proc/mounts; then
        mount --rbind /sys "${BASEDIR}/sys"
        mount --make-rslave "${BASEDIR}/sys"
fi

if ! grep -q "${BASEDIR}/dev" /proc/mounts; then
        mount --rbind /dev "${BASEDIR}/dev"
        mount --make-rslave "${BASEDIR}/dev"
fi

exec chroot "${BASEDIR}" /bin/bash