repackbootimg

#!/bin/sh

if [ $# -ne 1 ]; then
	echo "Usage: repackbootimg <name>" 1>&2
	exit 1
fi

name="$1"
newname="new$1"

for f in "$name.img-zImage" "$name.img-base" "$name.img-cmdline" "$name.img-ramdisk_offset" "$name.img-dt"; do
	if [ ! -f "$f" ]; then
		echo "File $f does not exist" 1>&2
		exit 1
	fi
done
if [ -d "initrd" ]; then
	(cd initrd; find . | cpio -H newc -R 0.0 -o | gzip > "../$newname.img-ramdisk.gz")
else
	if [ ! -f "$name.img-ramdisk.gz" ]; then
		echo "Cannot find ramdisk" 1>&2
		exit 1
	fi
	echo "Directory initrd not found: not repacking ramdisk"
	cp "$name.img-ramdisk.gz" "$newname.img-ramdisk.gz"
fi

if [ -f "$name.img-os_version" -a -f "$name.img-os_patch_level" ]; then
	os_version=$(cat $name.img-os_version)
	os_patch_level=$(cat $name.img-os_patch_level)
else
	os_version=0
	os_patch_level=0
fi

base="0x$(cat $name.img-base)"
koff="0x$(cat $name.img-kernel_offset)"
pgsz="$(cat $name.img-pagesize)"
cmd="$(cat $name.img-cmdline)"
rdimg="$newname.img-ramdisk.gz"
rdoff="0x$(cat $name.img-ramdisk_offset)"

# DT is optional
dtparam=""
if [ -f "$name.img-dt" ]; then
	dtsz=$(stat -c "%s" "$name.img-dt")
	if [ "$dtsz" -gt "$pgsz" ]; then
		dtparam="--dt $name.img-dt"
	fi
fi

mkbootimg \
	--kernel "$name.img-zImage" \
	--base "$base" \
	--kernel_offset "$koff" \
	--pagesize "$pgsz" \
	--cmdline "$cmd" \
	--ramdisk "$rdimg" \
	--ramdisk_offset "$rdoff" \
	$dtparam \
	--os_version $os_version \
	--os_patch_level $os_patch_level \
	 -o "$newname.img"

origsz=$(stat -c "%s" "$newname.img")
origmb=$((origsz / 1048576))
paddedsz=$((origmb * 1048576))
if [ "$origsz" -ne "$paddedsz" ]; then
	paddedmb=$((origmb+1))
	paddedsz=$((paddedmb * 1048576))
	padbytes=$((paddedsz - origsz))
	dd "if=/dev/zero" "bs=$padbytes" "count=1" 2>/dev/null >> "$newname.img"
fi