Initial commit

scripts/pad_image

@@ -0,0 +1,100 @@
+#!/usr/bin/env bash
+
+function usage {
+  echo "Usage: prepare_image image_type kernel_image rootfs_image header_size"
+  echo "Padd root and kernel image to the correct size and append the jffs2 start marker as needed"
+  exit 1
+}
+
+function pad_file {
+	echo "Padding $1 to size $2"
+	dd if=$1 of=$1.paddingtempfile bs=$2 count=1 conv=sync &> /dev/null
+	mv $1.paddingtempfile $1
+}
+
+#filesize filestart padding
+function calc_pad {
+	[  $((($1 + $2) & ($3 - 1))) == 0 ] && {
+		echo $1
+		return 0
+        }
+	echo $(((($1 + $2) | ($3 - 1)) + 1 - $2))
+}
+
+function prep_squash {
+	echo "kernel_size: $kernel_size"
+	echo "header_size: $header_size"
+	kernel_pad_size=$(calc_pad $kernel_size $header_size 32)
+	kernel_end=$(($header_size + $kernel_pad_size))
+	pad_file $kernel_image $kernel_pad_size
+
+	#4k
+	rootfs_pad_size=$(calc_pad $rootfs_size $kernel_end 4096)
+	pad_file $rootfs_image $rootfs_pad_size
+	echo -ne '\xde\xad\xc0\xde' >> $rootfs_image
+	
+	#8k
+	rootfs_pad_size=$(calc_pad $rootfs_size $kernel_end 8192)
+	[ $rootfs_pad_size == rootfs_old_padsize ] || {
+		pad_file $rootfs_image $rootfs_pad_size
+		rootfs_old_padsize=$rootfs_pad_size
+		echo -ne '\xde\xad\xc0\xde' >> $rootfs_image
+	}
+
+	#64k
+	rootfs_pad_size=$(calc_pad $rootfs_size $kernel_end 65536)
+	[ $rootfs_pad_size == rootfs_old_padsize ] || {
+		pad_file $rootfs_image $rootfs_pad_size
+		rootfs_old_padsize=$rootfs_pad_size
+		echo -ne '\xde\xad\xc0\xde' >> $rootfs_image
+	}
+
+	#128k
+	rootfs_pad_size=$(calc_pad $rootfs_size $kernel_end 131072)
+	[ $rootfs_pad_size == rootfs_old_padsize ] || {
+		pad_file $rootfs_image $rootfs_pad_size
+		rootfs_old_padsize=$rootfs_pad_size
+		echo -ne '\xde\xad\xc0\xde' >> $rootfs_image
+	}
+	
+}
+
+function prep_jffs2 {
+	kernel_pad_size=$(calc_pad $kernel_size $header_size $1)
+	pad_file $kernel_image $kernel_pad_size
+}
+
+image_type=$1
+kernel_image=$2
+rootfs_image=$3
+header_size=$4
+
+if [ -z "$image_type" ] || [ -z "$rootfs_image" ] || [ -z "$kernel_image" ] || [ -z "$header_size" ]; then
+	usage
+fi
+
+if [ ! -e "$rootfs_image" ] || [ -z "$kernel_image" ]; then
+	echo "input file not found"
+	exit 1
+fi
+
+kernel_size=$(stat -c "%s" "$kernel_image")
+rootfs_size=$(stat -c "%s" "$rootfs_image")
+
+if [ $kernel_size == 0 ] || [ $rootfs_size == 0 ]; then
+	echo "kernel or rootfs empty"
+	exit 1
+fi
+
+case $image_type in
+	squashfs )
+		prep_squash ;;
+	jffs2-64k )
+		prep_jffs2 65536 ;;
+	jffs2-128k )
+		prep_jffs2 131072 ;;
+	* )
+		echo "Unknown image type"
+		exit 1 ;;
+esac
+