#!/bin/sh

filename=$1
if [ -z $filename ]; then
    echo "Usage: sign_file.sh filename [ keyfile ]"
    exit 1
fi
keybasename=$2
if [ -z $keybasename ]; then
    keybasename=key
    keybasename=`echo $keybasename|sed "s/\.[a-z]*$//"`
fi

pq=`cat $keybasename.pub`
e="010001"

hash=`./sha256.exe $filename`

if [ -z $hash ]; then
    echo "error calculating sha256 of $filename"
    exit 1
fi
sig=`cat $filename.sig`
if [ -z $sig ]; then
    echo "could not find signature file $filename.sig"
    exit 1
fi

result=`echo "16 o 16 i $sig $e $pq | $hash - p"|dc`

if [ "$result" != "0" ]; then
    echo signature mismatch
    exit 1
fi