pdns-client/pdns-keygen

#!/bin/bash

umask 077

KEYNAME="pdns"
KEYSIZE=4096

exit_error() {
  echo "ERROR: ${1}" >&2
  exit 1
}

check_old_key() {
    if [ -f "$KEYNAME.private.pem" -o -f "$KEYNAME.public.pem" ]
    then
        exit_error "An old key is existing here, remove it first!"
    fi
}

check_dependencies() {
    openssl version > /dev/null 2>&1 || exit_error "This script requires an openssl binary."
}

print_help() {
cat << EOF
Usage: $0 [options]

Options are:
    -h         Show this help message
    -n NAME    Set basename of key to NAME (default pdns)
    -k SIZE    Use SIZE as rsa keysize (default 4096)
EOF

exit 0
}

#main
while getopts "n:s:h" opt
do
    case $opt in
        n)
            KEYNAME=$OPTARG
            ;;
        s)
            KEYSIZE=$OPTARG
            ;;
        h)
            print_help
            ;;
    esac
done

check_dependencies
check_old_key

echo "Generating rsa key pair with $KEYSIZE bits"
openssl genrsa -out "$KEYNAME.private.pem" "$KEYSIZE" >/dev/null 2>&1 || exit_error "Key generation failed."
echo "Extracting public key"
openssl rsa -in "$KEYNAME.private.pem" -out "$KEYNAME.public.pem" -outform PEM -pubout >/dev/null 2>&1 || exit_error "Pubkey extraction failed."