Script to patch ubuntu-core.snap at revision 122 to support the new hostfs mount point

patch-core-snap.sh

#!/bin/sh
if [ "$(id -u)" != 0 ]; then
    echo "This script requires root access, run it with sudo please"
    exit 1
fi
core_snap=/var/lib/snapd/snaps/ubuntu-core_122.snap
case $(md5sum $core_snap | cut -d ' ' -f 1) in
    8170579dcd67c5eceb151695c21cdab1)
        echo "Patching ubuntu-core snap to include hostfs mount point"
        tmp="$(mktemp -d)"
        trap 'rm -rf $tmp' EXIT 
        cd "$tmp" || exit 1
        unsquashfs "$core_snap"
        mkdir -p squashfs-root/var/lib/snapd/hostfs
        ( cd "$tmp/squashfs-root" && mksquashfs . "$core_snap" -noappend -comp xz -no-xattrs )
        umount /snap/ubuntu-core/122
        mount $core_snap /snap/ubuntu-core/122
        ;;
    4ac2f3a98f05acdd72bdf0b14ee6719d)
        echo "You are good to go, no patching is required"
        ;;
    *)
        echo "Hmm, unsure what to do here"
        exit 1
        ;;
esac