#! /usr/bin/env sh

# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.

main()
{
	# Handle opts
	opts "$@"
	shift "$OPTS"
	unset OPTS

	# Show help
	[ "$OPT_HELP_ONLY" ] && usage && exit 0
	[ -z "$1" ] && usage && exit 1

	# Generate fingerprint info for all certificates in question
	for crt in "$@"
	do
		printf "%s: \n" "$crt"
		for alg in md5 sha1 sha256
		do
			printf "  %-8s %s\n" "$alg" "$(fingerprint "$alg" "$crt")"
		done
	done
}

fingerprint()
{
	openssl x509 -noout -fingerprint "-$1" -inform pem -in "$2" \
		| awk -F= '{ print $NF }'
}

opts()
{
	OPTS=0

	while getopts ":h" opt
	do
		case "$opt" in
			h) OPT_HELP_ONLY=1 ;;
			*)
				printf "Invalid option passed: %s\n" "$OPTARG" >&2
				;;
		esac
	done

	unset opt
}

usage()
{
	cat <<EOF
Usage:
	$(basename "$0") -h
	$(basename "$0") [file [file...]]

Generate common fingerprints for a certificate, using openssl.

Options:
	-h  Show this help text and exit.
EOF
}

main "$@"