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Git merge driver to decrypt (and re-encrypt) files before merging.
#!/bin/bash
# WARNING: This creates and manipulates clear text copies of the
# encrypted files. It tries to clean up afterwards, but lots can go
# wrong. If you are seriously worried about the secrecy of the files,
# don't trust this!
ANCESTOR=$1
MINE=$2
OTHER=$3
WORKDIR=`mktemp -d`
if ! [ -d "$WORKDIR" ] || ! [ -x "$WORKDIR" ]; then
echo >&2 "Temp directory not created or not accessible: $WORKDIR"
rmdir "${WORKDIR}"
exit -1
fi
# Cleanup
cleanup() {
rm "$W_ANCESTOR" "$W_MINE" "$W_OTHER"
popd > /dev/null
rmdir "${WORKDIR}"
if [ -n "${2}" ]; then
echo >&2 $2
fi
exit $1
}
cp $ANCESTOR $WORKDIR/
cp $MINE $WORKDIR/
cp $OTHER $WORKDIR/
W_ANCESTOR=$WORKDIR/`basename $ANCESTOR`
W_MINE=$WORKDIR/`basename $MINE`
W_OTHER=$WORKDIR/`basename $OTHER`
#echo $ANCESTOR $MINE $OTHER $WORKDIR
pushd $WORKDIR > /dev/null
#Decrypt. Yes, you have to enter your password three times! (and two more to come)
gpg --output ${W_ANCESTOR}.plain --decrypt $ANCESTOR
[ $? -eq 0 ] || cleanup -1 "Decryption error: Abort merge"
gpg --output ${W_MINE}.plain --decrypt $MINE
[ $? -eq 0 ] || cleanup -1 "Decryption error: Abort merge"
gpg --output ${W_OTHER}.plain --decrypt $OTHER
[ $? -eq 0 ] || cleanup -1 "Decryption error: Abort merge"
#XXX Can we import the merge (mergetool) preferences for the original file and use them here?
git-merge-file -L "Ours" -L "Common Ancestor" -L "Theirs" ${W_MINE}.plain ${W_ANCESTOR}.plain ${W_OTHER}.plain
[ $? -ge 0 ] || cleanup -2 "Git merge error."
echo >&2 "Plaintext files merged. Re-encrypting."
gpg --output merged.gpg --symmetric ${W_MINE}.plain
[ $? -eq 0 ] || cleanup -3 "Re-encryption error"
#Replace original current/our file with merged, encrypted version
cp -f merged.gpg ${MINE}
if [ -x /usr/bin/shred ]; then
echo >&2 "Shredding plain-text files. Do not be fooled -- this doesn't mean it's truly gone!"
/usr/bin/shred -u ${W_ANCESTOR}.plain ${W_MINE}.plain ${W_OTHER}.plain
rm -f merged.gpg
else
rm -f ${W_ANCESTOR}.plain ${W_MINE}.plain ${W_OTHER}.plain
rm -f merged.gpg
fi
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