Hi, > I would suggest adding some kind of version field (2 bytes, value "01" > or "10") just after the magic and bumping file names to 32 bytes as > well.
the version field is a good idea. It now looks like this: # 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 Regards, Marek
scripts: add script to generate combined extended image format Signed-off-by: Marek Lindner <lindner_ma...@yahoo.de> --- --- /dev/null +++ b/scripts/combined-ext-image.sh @@ -0,0 +1,59 @@ +#!/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 + +usage() { + echo "Usage: $0 <type> <ext filename> <file1> <filename1> [<file2> <filename2> <fileN> <filenameN>]" + [ "$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 "Not a valid file: $file" && usage + FILES="$FILES $file" + md5=$(cat "$file" | md5sum -) + printf "%-32s%08x%32s" "$filename" $(stat -c "%s" "$file") "${md5%% *}" >> $IMG_OUT + shift 2 + done + +[ "$#" -eq 1 ] && echo "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
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