#!/bin/sh

arch=aarch64
rootpath=/home/jejb/tmp
ctrl=/run/build-container

while true; do
    case $1 in
	--arch)
	    arch=$2; shift; shift ;;
	--rootpath)
	    rootpath=$2; shift; shift ;;
	*)
	    break;;
    esac
done

ctroot=$rootpath/$arch
root=$ctrl/root-$arch
if [ "$1" == "in-ct" ]; then
    mount --bind $ctroot $root
    mkdir $root$ctrl
    for f in /dev /dev/pts /proc /sys /home $ctrl /var/tmp /etc/resolv.conf; do
	mount --bind $f ${root}${f}
	mount --make-rprivate ${root}${f}
    done
    mount --bind /usr/bin/qemu-$arch $root/qemu-$arch
    cd $root
    mkdir old-root
    pivot_root . old-root
    mount --make-rprivate /old-root
    umount -l /old-root
    # spawn an undying process into the mount namespace as me to keep it alive
    sleep 365d &
    pid=$!
    # create a link to allow entry
    ln -s /proc/$pid/ns/mnt $ctrl/$arch
else
    if [ -e $ctrl/$arch ]; then
	echo "Error: $ctrl/$arch exists, is container running?"
	exit 1;
    fi
    if [ ! -d $ctrl ]; then
	mkdir $ctrl || exit 1
    fi
    if grep -q "$ctrl tmpfs" /proc/self/mounts; then
	:
    else
	mount -t tmpfs none $ctrl || exit 1
    fi
    mount --make-rprivate $ctrl
    mkdir $root
    unshare --mount $0 --arch $arch --rootpath $rootpath in-ct
    rmdir $root
fi