Root/scripts/combined-ext-image.sh

1#!/bin/sh
2#
3# Copyright (C) 2011 OpenWrt.org
4#
5# This is free software, licensed under the GNU General Public License v2.
6# See /LICENSE for more information.
7#
8
9# Write image header followed by all specified files
10# The header is padded to 64k, format is:
11# CE magic word ("Combined Extended Image") (2 bytes)
12# <CE_VERSION> file format version field (2 bytes)
13# <TYPE> short description of the target device (32 bytes)
14# <NUM FILES> number of files following the header (2 byte)
15# <file1_name> name of the first file (32 bytes)
16# <file1_length> length of the first file encoded as zero padded 8 digit hex (8 bytes)
17# <file1_md5> md5 checksum of the first file (32 bytes)
18# <fileN_name> name of the Nth file (32 bytes)
19# <fileN_length> length of the Nth file encoded as zero padded 8 digit hex (8 bytes)
20# <fileN_md5> md5 checksum of the Nth file (32 bytes)
21
22## version history
23# * version 1: initial file format with num files / name / length / md5 checksum
24
25ME="${0##*/}"
26
27usage() {
28    echo "Usage: $ME <type> <ext filename> <file1> <filename1> [<file2> <filename2> <fileN> <filenameN>]"
29    [ "$IMG_OUT" ] && rm -f "$IMG_OUT"
30    exit 1
31}
32
33[ "$#" -lt 4 ] && usage
34
35CE_VERSION=1
36IMG_TYPE=$1; shift
37IMG_OUT=$1; shift
38FILE_NUM=$(($# / 2))
39FILES=""
40
41printf "CE%02x%-32s%02x" $CE_VERSION "$IMG_TYPE" $FILE_NUM > $IMG_OUT
42
43while [ "$#" -gt 1 ]
44   do
45      file=$1
46      filename=$2
47
48      [ ! -f "$file" ] && echo "$ME: Not a valid file: $file" && usage
49      FILES="$FILES $file"
50      md5=$(cat "$file" | md5sum -)
51      printf "%-32s%08x%32s" "$filename" $(stat -c "%s" "$file") "${md5%% *}" >> $IMG_OUT
52      shift 2
53   done
54
55[ "$#" -eq 1 ] && echo "$ME: Filename not specified: $1" && usage
56
57mv $IMG_OUT $IMG_OUT.tmp
58dd if="$IMG_OUT.tmp" of="$IMG_OUT" bs=65536 conv=sync 2>/dev/null
59rm $IMG_OUT.tmp
60
61cat $FILES >> $IMG_OUT
62

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