#!/bin/bash
#
# Generate a DKIM key for Postfix
#
#  Project info
#    https://gitpull.it/w/kiss_libre_hosting_panel/
#
#  Updates
#    https://gitpull.it/P13
#
#  This script is in public domain.
#    2020 - Valerio Bozzolan
###################################################

# die in case of errors
set -e

# expected pathnames
POSTFIX=/etc/postfix
DKIM="$POSTFIX"/dkim
KEYTABLE="$DKIM"/keytable
SIGNINGTABLE="$DKIM"/signingtable
DKIM_KEYS="$DKIM"/dkimkeys

# no domain no party
domain="$1"
if [ -z "$domain" ]; then
	echo "Please insert the domain name and press enter"
	read domain
fi

# no selector no party
selector="$2"
if [ -z "$2" ]; then
	date="`date +%Y%m`"

	# make domain shorter
	domainshort="${domain:0:10}"

	# strip dots
	domainshort=$(echo "$domainshort" | sed 's/\.//g')

	selector="$domainshort""$date"
fi

# expected pathnames
keytablename="$selector"key
expected_filename_prv="$selector".private
expected_filename_txt="$selector".txt
expected_filepath_prv="$DKIM_KEYS"/"$expected_filename_prv"
expected_filepath_txt="$DKIM_KEYS"/"$expected_filename_txt"

# key generation
opendkim-genkey --verbose --bits=1024 "--domain=$domain" "--selector=$selector" "--directory=$DKIM_KEYS"

# this line should be at the beginning of the file
sed -i "1s/^/*@$domain           $keytablename\n/" "$SIGNINGTABLE"

# this line can be appended at the end of the table
echo "$keytablename      $domain:$selector:$expected_filepath_prv" >> "$KEYTABLE"

# eventually fix privileges
chown --verbose opendkim: "$expected_filepath_prv" "$expected_filepath_txt"

cat "$expected_filepath_txt"
echo
echo "Done!"
echo "    systemctl reload opendkim"
echo "    opendkim-testkey -d '$domain' -s '$selector' -vvv"