#!/bin/sh
###############################################################################
# BRLTTY - A background process providing access to the console screen (when in
#          text mode) for a blind person using a refreshable braille display.
#
# Copyright (C) 1995-2014 by The BRLTTY Developers.
#
# BRLTTY comes with ABSOLUTELY NO WARRANTY.
#
# This is free software, placed under the terms of the
# GNU General Public License, as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any
# later version. Please see the file LICENSE-GPL for details.
#
# Web Page: http://mielke.cc/brltty/
#
# This software is maintained by Dave Mielke <dave@mielke.cc>.
###############################################################################

# Generate a key for BrlAPI.
# Usage: brltty-genkey [/path/to/file]

programName="${0}"
programMessage() {
   echo "${programName}: ${1}"
}
syntaxError() {
   programMessage "${1}"
   exit 2
}

try() {
   ("${@}"; exit "${?}") 2>/dev/null && exit 0
}

if [ "${#}" -eq 0 ]
then
   . "`dirname "${0}"`/brltty-config" || exit "${?}"
   file="${BRLTTY_EXECUTE_ROOT}${sysconfdir}/${BRLAPI_AUTHKEYFILE}"
elif [ "${#}" -eq 1 ]
then
   file="${1}"
else
   syntaxError "too many parameters."
fi

umask 077

try mcookie >"${file}"

for device in "/dev/urandom" "/dev/random"
do
   [ -c "${device}" -a -r "${device}" ] && {
      try dd if="${device}" of="${file}" bs=32 count=1
   }
done

key="${RANDOM}"
[ -n "${key}" ] && {
   try echo >"${file}" "${key}"
}

programMessage "no known mechanism is supported."
rm -f -- "${file}"
exit 3
