#!/bin/bash

MOUNTPOINT="/mnt/containerfs"

mkdir -p /mnt/containerfs

# see if we should bail to the bootstrap or pivot into the container
# do this before the fork so we don't have a backdoor call in the hot path
# NOTE: this is moved after the fork during debugging so we can chose on a per VM basis
SHELL=`/sbin/rpctool -get bootstrap-shell 2>/dev/null`

echo "Waiting for rootfs"
while [ ! -e /dev/disk/by-label/containerfs ]; do :;done
if mount -t ext4 /dev/disk/by-label/containerfs ${MOUNTPOINT}; then
    # make the required directory structure, but presume that something in the daemon
    # has done the *right* thing for /.tether* and created them where it won't show in a diff
    # we do this to ensure that subsequent commands don't fail if the daemon hasn't prepped
    # the structure
    mkdir -p ${MOUNTPOINT}/.tether ${MOUNTPOINT}/.tether-init

    # ensure that no matter what we have access to required devices
    # WARNING WARNING WARNING WARNING WARNING
    # if the tmpfs is not large enough odd hangs can occur and the ESX event log will
    # report the guest disabling the CPU
    mount -t tmpfs -o size=128m tmpfs ${MOUNTPOINT}/.tether/

    # if we don't have a populated init layer, pull from guestinfo
    if [ ! -f ${MOUNTPOINT}/.tether-init/docker-id ]; then
        mount -t tmpfs -o size=1m tmpfs ${MOUNTPOINT}/.tether-init/
        # create the assumed structure
        # TODO: this cannot be in guest and still not show up in diffs
        mkdir -p ${MOUNTPOINT}/dev ${MOUNTPOINT}/proc ${MOUNTPOINT}/sys ${MOUNTPOINT}/etc
        # ln -sf /proc/mounts ${MOUNTPOINT}/etc/mtab

        touch ${MOUNTPOINT}/etc/hostname
        touch ${MOUNTPOINT}/etc/hosts
        touch ${MOUNTPOINT}/etc/resolv.conf
    fi

    # this is so we're not exposing the raw container disk if we wouldn't be otherwise
    #	rm -f /mnt/.tether/volumes/containerfs

    # enable full system functionality in the container
    echo "Publishing modules within container"
    mkdir -p ${MOUNTPOINT}/lib/modules
    mount --bind /lib/modules ${MOUNTPOINT}/lib/modules

    # switch to the new root
    echo "prepping for switch to container filesystem"

    cp /bin/tether ${MOUNTPOINT}/.tether/tether-debug

    echo "switching to the new mount"
    if [ "$SHELL" != "true" ]; then
        systemctl switch-root ${MOUNTPOINT} /.tether/tether-debug 2>&1
    else
        systemctl switch-root ${MOUNTPOINT} /bin/sh 2>&1
        # fail back to shell in bootstrap image without switch_root
        /bin/ash
    fi
else
    # TODO: what do we do here? we really need to somehow report an error
    # fail hard
    echo "Unable to chroot into container filesystem"
fi