Add image size check to hdd-image.sh (#2965)

There is no sanity check when creating OS images, so when some of the
partitions gets too big, part of its data may get overwritten by the
following partition, resulting in corrupted image. Add checks for the
defined partition sizes and bail out if they're too big.

buildroot-external/scripts/hdd-image.sh

@@ -43,6 +43,22 @@ function size2sectors() {
 }
 
 
+function _check_image_size() {
+    local image="${1}"
+    local max_size="${2}"
+
+    local image_size=$(stat -c %s "${image}")
+    local image_size_sectors=$((image_size / 512))
+    local max_size_sectors=$(size2sectors "${max_size}")
+
+
+    if [ "${image_size_sectors}" -gt "${max_size_sectors}" ]; then
+        echo "Image ${image} is too big: ${image_size_sectors} sectors > ${max_size_sectors} sectors" >&2
+        exit 1
+    fi
+}
+
+
 function get_boot_size() {
     # shellcheck disable=SC2153
     echo "${BOOT_SIZE}"
@@ -66,6 +82,8 @@ function create_boot_image() {
     truncate --size="$(get_boot_size)" "${boot_img}"
     mkfs.vfat -n "hassos-boot" "${boot_img}"
     mcopy -i "${boot_img}" -sv "${boot_data}"/* ::
+
+    _check_image_size "${boot_img}" "$(get_boot_size)"
 }
 
 
@@ -75,6 +93,8 @@ function create_overlay_image() {
     rm -f "${overlay_img}"
     truncate --size="${OVERLAY_SIZE}" "${overlay_img}"
     mkfs.ext4 -L "hassos-overlay" -I 256 -E lazy_itable_init=0,lazy_journal_init=0 "${overlay_img}"
+
+    _check_image_size "${overlay_img}" "${OVERLAY_SIZE}"
 }
 
 
@@ -86,10 +106,15 @@ function create_kernel_image() {
     # Make image
     rm -f "${kernel_img}"
     mksquashfs "${kernel}" "${kernel_img}" -comp lzo
+
+    _check_image_size "${kernel_img}" "${KERNEL_SIZE}"
 }
 
 
 function _prepare_disk_image() {
+    _check_image_size "$(path_data_img)" "${DATA_SIZE}"
+    _check_image_size "$(path_rootfs_img)" "${SYSTEM_SIZE}"
+
     create_boot_image
     create_overlay_image
     create_kernel_image