scripts/signrom.sh

   1 #!/bin/sh
   2
   3 # Option ROM Signing utility
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, see <http://www.gnu.org/licenses/>.
  17 #
  18 # Copyright Novell Inc, 2009
  19 #   Authors: Alexander Graf <agraf@suse.de>
  20 #
  21 # Syntax: signrom.sh <input> <output>
  22
  23 # did we get proper arguments?
  24 test "$1" -a "$2" || exit 1
  25
  26 sum=0
  27
  28 # find out the file size
  29 x=`dd if="$1" bs=1 count=1 skip=2 2>/dev/null | od -t u1 -A n`
  30 #size=`expr $x \* 512 - 1`
  31 size=$(( $x * 512 - 1 ))
  32
  33 # now get the checksum
  34 nums=`od -A n -t u1 -v -N $size "$1"`
  35 for i in ${nums}; do
  36     # add each byte's value to sum
  37     sum=`expr \( $sum + $i \) % 256`
  38 done
  39
  40 sum=$(( (256 - $sum) % 256 ))
  41 sum_octal=$( printf "%o" $sum )
  42
  43 # and write the output file
  44 cp "$1" "$2"
  45 printf "\\$sum_octal" | dd of="$2" bs=1 count=1 seek=$size conv=notrunc 2>/dev/null