diff options
Diffstat (limited to 'mkrootimg')
| -rwxr-xr-x | mkrootimg | 145 |
1 files changed, 86 insertions, 59 deletions
@@ -3,36 +3,19 @@ set -e print_usage() { cat 1>&2 <<EOF -Usage: $0 rootfs-directory image -Package the contents of a directory into an ext4-based binary image file. +Usage: $0 <rootfs_directory> <image_file> +Package the contents of a debian root filesystem into a binary image file, ready to be burned onto an sd card. EOF } -# Process options -# -while [ $# -gt 2 ] -do - case "$1" in - --help|-h) - print_usage - exit 0 - ;; - *) - echo "Unknown option '$1'" 1>&2 - exit 1 - esac - shift -done - -# Process last argument, the root file system location -if [ -z "$1" ] || [ -z "$2" ] || [ "$1" = -h ] || [ "$1" = --help ]; then - print_usage - exit 1 -fi -if [ "$EUID" -ne 0 ]; then - echo "This must be run as root." 1>&2 +fail() { + echo "$1" >&2 exit 1 -fi +} + +log() { + echo "mkrootimg: $1" >&2 +} # Directory to package rootfs="$1" @@ -40,46 +23,90 @@ rootfs="$1" # Binary image file image="$2" -# Number of 512-byte sectors reserved at the beginning of the image -# (usually 1M for e.g. a bootloader) -table_sectors=$(expr 1 \* 1024 \* 1024 \/ 512) - -# Calculate size of the rootfs directory in KB -rootfs_size=$(expr `du -s "${rootfs}" | awk '{ print $1 }'`) - -# The root partition is EXT4 -# This means more space than the actual used space of the rootfs is used. -# As overhead for journaling and reserved blocks 25% are added. -rootfs_sectors=$(expr $(expr ${rootfs_size} + ${rootfs_size} \/ 100 \* 25) \* 1024 \/ 512) +# Contains temporary build files +builddir=$(mktemp -d) -# Calculate required image size in 512 Byte sectors -image_sectors=$(expr ${table_sectors} + ${rootfs_sectors}) +([ -n "$rootfs" ] && [ -n "$image" ]) || fail "$(print_usage)" +[ -d "$rootfs" ] || fail "$rootfs does not exist or is not a directory" +[ ! -e "$image" ] || fail "$image already exists" -# Initialize image file -dd if=/dev/zero of="$image" bs=512 count=${table_sectors} -dd if=/dev/zero of="$image" bs=512 count=0 seek=${image_sectors} - -# Write partition table -sfdisk "$image" <<EOF -${table_sectors},${rootfs_sectors},L,* -EOF - -# Setup temporary loop devices -image_loop="$(losetup -o 1M -f --show $image)" - -mkfs.ext4 -O^64bit "$image_loop" +[ "$EUID" -eq 0 ] || fail "$0 must be run as root" cleanup() { - losetup -d "$image_loop" 2> /dev/null + set +e + umount --lazy "$builddir/mount/boot/firmware" 2> /dev/null + umount --lazy "$builddir/mount" 2> /dev/null + sync + losetup --detach "$bootfs_loop" 2> /dev/null + losetup --detach "$rootfs_loop" 2> /dev/null + rm -rf "$builddir" trap - 0 1 2 3 6 } trap cleanup 0 1 2 3 6 -# Mount the temporary loop devices -mount_dir=$(mktemp -d) -mount "$image_loop" "$mount_dir" +# Partition layout +# +# Content Size +# --------------------------------------------- +# reserved 1024k (1M, for e.g. a bootloader) +# bootfs 100*1024k (100M) +# rootfs as required + +# size in bytes +reserved_size=1024*1024 +bootfs_size=$((100*1024*1024)) +rootfs_size=$(du --block-size=1 -s "$rootfs" | awk '{ print $1 }') + +# converted to 512-byte sectors +reserved_sectors=$(( $reserved_size / 512 )) +bootfs_sectors=$(( $bootfs_size / 512 )) +# as overhead for journaling and reserved blocks 25% are added. +rootfs_sectors=$(( ($rootfs_size + $rootfs_size * 25 / 100) / 512 )) +image_sectors=$(( $reserved_sectors + $bootfs_sectors + $rootfs_sectors )) + +# create empty image file +log "creating empty image" +dd if=/dev/zero of="$image" bs=512 count="$image_sectors" status=none + +# write partition table to image +log "partitioning image" +sfdisk --label dos -q -uS "$image" <<EOF > /dev/null +$reserved_sectors,$bootfs_sectors,c,* +,$rootfs_sectors,L, +EOF -# Copy all files from the chroot to the loop device mount point directory -rsync -a "$rootfs/" "$mount_dir" -umount "$mount_dir" +# set up temporary loop devices +log "setting up image loop devices" +bootfs_loop=$(losetup \ + --offset $(( $reserved_sectors * 512 )) \ + --sizelimit $(( $bootfs_sectors * 512 )) \ + --find \ + --show \ + "$image") +rootfs_loop=$(losetup \ + --offset $(( ($reserved_sectors + $bootfs_sectors) * 512 )) \ + --sizelimit $(( $rootfs_sectors * 512 )) \ + --find \ + --show \ + "$image") + +# format partitions +log "formatting partitions" +mkfs.vfat -F 32 "$bootfs_loop" &> /dev/null +mkfs.ext4 -O^64bit "$rootfs_loop" &> /dev/null + +# mount partitions +log "mounting partitions" +mkdir -p "$builddir/mount" +mount "$rootfs_loop" "$builddir/mount" +mkdir -p "$builddir/mount/boot/firmware" +mount "$bootfs_loop" "$builddir/mount/boot/firmware" + +# copy root filesystem to image +log "copying root filesystem" +rsync -a "$rootfs/" "$builddir/mount/" + +log "cleaning up" cleanup + +log "done" |