#! /bin/sh

# Generates a random key for munged

#

# (C) 2007 Gennaro Oliva

# You may freely distribute this file under the terms of the GNU General

# Public License, version 2 or later.

#Setting default random file

randomfile=/dev/urandom

#Usage message

usage="Try \`$0 -h' for more information."

#Help message

needhelp() {

echo Usage: create-munge-key [OPTION]...

echo Generates a random key for munged

echo List of options

echo "  -f            force overwriting existing old key"

echo "  -r            specify /dev/random as random file for key generation"

echo "                default is /dev/urandom"

echo "  -h            display this help and exit"

}

#Parsing command line options

while getopts "hrf" options; do

  case $options in

    r ) randomfile=/dev/random;;

    f ) force=yes;;

    h ) needhelp

        exit 0;;

    \? ) echo $usage

         exit 1;;

    * ) echo $usage

          exit 1;;

  esac

done

if [ `id -u` != 0 ] ; then

  echo "Please run create-munge-key as root."

  exit 1

fi

#Checking random file presence

if [ ! -e $randomfile ] ; then 

  echo $0: cannot find random file $randomfile

  exit 1

fi

#Checking if the user want to overwrite existing key file

if [ "$force" != "yes" ] && [ -e /etc/munge/munge.key ] ; then

  echo The munge key /etc/munge/munge.key already exists

  echo -n "Do you want to overwrite it? (y/N) "

  read ans

  if [ "$ans" != "y" -a "$ans" != "Y" ] ; then

    exit 0

  fi

fi

#Generating the key file and change owner and permissions

if [ "$randomfile" = "/dev/random" ] ; then 

  echo Please type on the keyboard, echo move your mouse,

  echo utilize the disks. This gives the random number generator

  echo a better chance to gain enough entropy.

fi

echo -n "Generating a pseudo-random key using $randomfile "

dd if=$randomfile bs=1 count=1024 > /etc/munge/munge.key \

  2>/dev/null

chown munge:munge /etc/munge/munge.key

chmod 0400 /etc/munge/munge.key

echo completed.

exit 0