#!/bin/bash
set -e
print_usage() {
echo "Usage: $(basename $0) [options]"
echo -e "Creates a Ubuntu root file system image.\n"
echo -e " --help\t\t\tDisplay this information."
echo -e " --arch {armhf|arm64}\t\tSelects architecture of rootfs image."
echo -e " --distro {bionic|focal}\tSelects Ubuntu distribution of rootfs image."
echo -e " --size n{K|M|G}\t\tSets size of rootfs image to n Kilo, Mega or Giga bytes."
exit "$1"
}
invalid_arg() {
echo "ERROR: Unrecognized argument: $1" >&2
print_usage 1
}
update_repositories() {
echo -e "\nUpdating apt repositories. "
echo -e "\nPress 'y' to continue or any other key to exit..."
read -s -n 1 user_input
if [[ $user_input == 'Y' ]] || [[ $user_input == 'y' ]]; then
sudo apt update
else
exit
fi
}
# Parse options
while [[ $# -gt 0 ]]; do
case "${END_OF_OPT}${1}" in
--help) print_usage 0 ;;
--arch) rfs_arch=$2; shift;;
--distro) rfs_distro=$2; shift;;
--size) rfs_size=$2; shift;;
*) invalid_arg "$1" ;;
esac
shift
done
if [ -z "$rfs_arch" ]; then
echo "Missing architecture"
print_usage 1
fi
if [ -z "$rfs_distro" ]; then
echo "Missing distribution"
print_usage 1
fi
if [ -z "$rfs_size" ]; then
echo "Missing size"
print_usage 1
fi
if [[ "$rfs_arch" != "arm64" && "$rfs_arch" != "armhf" ]]; then
echo "Invalid architecture: $rfs_arch"
print_usage 1
fi
pat='^[0-9]+[K|M|G]$'
if [[ ! $rfs_size =~ $pat ]]; then
echo "Invalid size: $rfs_size"
print_usage 1
fi
update_repositories
echo "Installing build dependencies ..."
sudo apt-get install debootstrap qemu-user-static schroot qemu-utils
image_name=$rfs_distro-$rfs_arch-"rootfs"
echo "Creating $rfs_distro ($rfs_arch) root file system ..."
echo "Image name: $image_name.img"
echo "Image size: $rfs_size"
qemu-img create $image_name.img $rfs_size
mkfs.ext4 $image_name.img
mkdir $image_name.dir
sudo mount -o loop $image_name.img $image_name.dir
sudo qemu-debootstrap --arch $rfs_arch $rfs_distro $image_name.dir
sudo chroot $image_name.dir locale-gen en_US.UTF-8
sudo chroot $image_name.dir sed -i \
's/main/main restricted multiverse universe/g' /etc/apt/sources.list
sudo chroot $image_name.dir sed -i '$ a\nameserver 8.8.8.8' /etc/resolv.conf
sudo chroot $image_name.dir apt update
sudo chroot $image_name.dir apt -y install ssh bash-completion
sudo chroot $image_name.dir adduser --gecos "" $USER
sudo chroot $image_name.dir adduser $USER sudo
sudo umount $image_name.dir
rmdir $image_name.dir