openwrt/scripts/combined-ext-image.sh

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#!/bin/sh
#
# Copyright (C) 2011 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
# Write image header followed by all specified files
# The header is padded to 64k, format is:
# CE magic word ("Combined Extended Image") (2 bytes)
# <CE_VERSION> file format version field (2 bytes)
# <TYPE> short description of the target device (32 bytes)
# <NUM FILES> number of files following the header (2 byte)
# <file1_name> name of the first file (32 bytes)
# <file1_length> length of the first file encoded as zero padded 8 digit hex (8 bytes)
# <file1_md5> md5 checksum of the first file (32 bytes)
# <fileN_name> name of the Nth file (32 bytes)
# <fileN_length> length of the Nth file encoded as zero padded 8 digit hex (8 bytes)
# <fileN_md5> md5 checksum of the Nth file (32 bytes)
## version history
# * version 1: initial file format with num files / name / length / md5 checksum
ME="${0##*/}"
usage() {
echo "Usage: $ME <type> <ext filename> <file1> <filename1> [<file2> <filename2> <fileN> <filenameN>]"
[ "$IMG_OUT" ] && rm -f "$IMG_OUT"
exit 1
}
[ "$#" -lt 4 ] && usage
CE_VERSION=1
IMG_TYPE=$1; shift
IMG_OUT=$1; shift
FILE_NUM=$(($# / 2))
FILES=""
printf "CE%02x%-32s%02x" $CE_VERSION "$IMG_TYPE" $FILE_NUM > $IMG_OUT
while [ "$#" -gt 1 ]
do
file=$1
filename=$2
[ ! -f "$file" ] && echo "$ME: Not a valid file: $file" && usage
FILES="$FILES $file"
md5=$(mkhash md5 "$file")
printf "%-32s%08x%32s" "$filename" $(stat -c "%s" "$file") "${md5%% *}" >> $IMG_OUT
shift 2
done
[ "$#" -eq 1 ] && echo "$ME: Filename not specified: $1" && usage
mv $IMG_OUT $IMG_OUT.tmp
dd if="$IMG_OUT.tmp" of="$IMG_OUT" bs=65536 conv=sync 2>/dev/null
rm $IMG_OUT.tmp
cat $FILES >> $IMG_OUT