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
  25 ME="${0##*/}"
  26
  27 usage() {
  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
  35 CE_VERSION=1
  36 IMG_TYPE=$1; shift
  37 IMG_OUT=$1; shift
  38 FILE_NUM=$(($# / 2))
  39 FILES=""
  40
  41 printf "CE%02x%-32s%02x" $CE_VERSION "$IMG_TYPE" $FILE_NUM > $IMG_OUT
  42
  43 while [ "$#" -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
  57 mv $IMG_OUT $IMG_OUT.tmp
  58 dd if="$IMG_OUT.tmp" of="$IMG_OUT" bs=65536 conv=sync 2>/dev/null
  59 rm $IMG_OUT.tmp
  60
  61 cat $FILES >> $IMG_OUT