overlay-here

#!/usr/bin/env sh

if test ! -d ./overlay; then
    read -p "No overlay found here. Want to create one? (y/N)" yn
    case $yn in
        [Yy]* ) install -d overlay/upperdir && install -d overlay/workdir && install -d overlay/mnt; break;;
        * ) exit;;
    esac
fi

if test ! -d ./overlay/upperdir; then
    echo "Missing overlay/upperdir. Broken overlay?"
    exit
fi

if test ! -d ./overlay/workdir; then
    echo "Missing overlay/workdir. Broken overlay?"
    exit
fi

if test ! -d ./overlay/mnt; then
    echo "Missing overlay/mnt. Broken overlay?"
    exit
fi

echo "Entering own mount namespace..."
sudo unshare -m sh -c "echo 'Mounting local overlay...' && \
    mount -t overlay overlay -o upperdir=$(pwd)/overlay/upperdir,workdir=$(pwd)/overlay/workdir,lowerdir=/ $(pwd)/overlay/mnt && \
    mount -o bind /sys overlay/mnt/sys && \
    mount -t proc none overlay/mnt/proc && \
    mount -o bind /dev overlay/mnt/dev && \
    mount -o bind /dev/pts overlay/mnt/dev/pts && \
    echo 'chrooting...' && \
    sudo chroot overlay/mnt sh -c 'export action=\"(chroot) \"; cd $(pwd) && sudo -E -u $(whoami) $SHELL'"