#!/bin/sh


for pkg in $*
do
if [ "$pkg" = "" -o ! -e "$pkg" ]; then
echo "no package supplied" 1>&2
exit 1
fi

plaintext=`mktemp ${TMPDIR:-/tmp}/tgpg-$$.XXXXXX`
detached=`mktemp ${TMPDIR:-/tmp}/tgpg-$$.XXXXXX`

# --- Extract detached signature
rpm -qp -vv --qf '%{siggpg:armor}' $pkg > $detached

# --- Figger the offset of header+payload in the package
leadsize=96
o=`expr $leadsize + 8`

set `od -j $o -N 8 -t u1 $pkg`
il=`expr 256 \* \( 256 \* \( 256 \* $2 + $3 \) + $4 \) + $5`
dl=`expr 256 \* \( 256 \* \( 256 \* $6 + $7 \) + $8 \) + $9`

sigsize=`expr 8 + 16 \* $il + $dl`
o=`expr $o + $sigsize + \( 8 - \( $sigsize \% 8 \) \) \% 8`

# --- Extract header+payload
dd if=$pkg ibs=$o skip=1 2>/dev/null > $plaintext

# --- Verify DSA signature using gpg
gpg --batch -vv --debug 0xfc02 --verify $detached $plaintext

# --- Clean up
rm -f $detached $plaintext
done