#!/bin/sh
# デバイスイメージファイルの生成
# Usage: bin/img-gen source dist.img
# Required: fallocate gzip losetup mkfs.fat parted rsync
set -eux
size=1.6G
src="$1"
image="$2"
fallocate -l "${size}" "${image}"
parted --script "${image}" \
  mklabel gpt \
  mkpart p1 0 100% \
  set 1 esp on
dev="$(losetup -f)"
finally="losetup -d '${dev}'"
trap 'sh -c "${finally}"' EXIT
losetup -P "${dev}" "${image}"
part="${dev}p1"
mkfs.fat -n CIDATA "${part}"
tmp="$(mktemp -d)"
finally="rmdir '${tmp}'; ${finally}"
mount "${part}" "${tmp}"
finally="umount '${tmp}'; ${finally}"
rsync -rtv "${src}/" "${tmp}/"
finally="${finally}; gzip -f '${image}'"