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