freebsd-skq/libexec/save-entropy/save-entropy.sh
dougb 83d50f9dde 1. Use install -d to create the entropy_dir if missing so that we can do it
all in one command, with no permissions race.
2. Simplify the rotation logic by cd'ing into the directory, with a test
   to make sure that it succeeds.
3. Remove any files numbered higher than entropy_save_num. This helps when
   the user reduces the number, and may be useful for other purposes down
   the road.
4. Simplify the rotation logic by first testing the common case (it's a
   regular file) then testing if something else exists with the same name
   using elif. Also switch from using jot to simpler countdown format.
5. Fix logger lines and error messages to be more consistent, and wrap the
   code more consistently in the 80 column range. The "not a regular file"
   error message was mistakenly wrapped entirely in "quotes" which caused
   logger to include line-wrapping whitespace. Change that to wrap only
   the variables in quotes, which is both consistent and works better.
6. Update copyright to reflect the fact that changes were made this year.

Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00

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#!/bin/sh
#
# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
# This script is called by cron to store bits of randomness which are
# then used to seed /dev/random on boot.
# Originally developed by Doug Barton, dougb@FreeBSD.org
PATH=/bin:/usr/bin
# If there is a global system configuration file, suck it in.
#
if [ -r /etc/defaults/rc.conf ]; then
. /etc/defaults/rc.conf
source_rc_confs 2>/dev/null
elif [ -r /etc/rc.conf ]; then
. /etc/rc.conf 2>/dev/null
fi
case ${entropy_dir} in
[Nn][Oo])
exit 0
;;
*)
entropy_dir=${entropy_dir:-/var/db/entropy}
;;
esac
entropy_save_sz=${entropy_save_sz:-2048}
entropy_save_num=${entropy_save_num:-8}
if [ ! -d "${entropy_dir}" ]; then
install -d -o operator -g operator -m 0700 "${entropy_dir}" || {
logger -is -t "$0" The entropy directory "${entropy_dir}" does \
not exist, and cannot be created. Therefore no entropy can \
be saved.; exit 1; }
fi
cd "${entropy_dir}" || {
logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \
Entropy file rotation is aborted.; exit 1; }
for f in saved-entropy.*; do
case "${f}" in saved-entropy.\*) continue ;; esac # No files match
[ ${f#saved-entropy\.} -ge ${entropy_save_num} ] && unlink ${f}
done
umask 377
n=$(( ${entropy_save_num} - 1 ))
while [ ${n} -ge 1 ]; do
if [ -f "saved-entropy.${n}" ]; then
mv "saved-entropy.${n}" "saved-entropy.$(( ${n} + 1 ))"
elif [ -e "saved-entropy.${n}" -o -L "saved-entropy.${n}" ]; then
logger -is -t "$0" \
"${entropy_dir}/saved-entropy.${n}" is not a regular file, and so \
it will not be rotated. Entropy file rotation is aborted.
exit 1
fi
n=$(( ${n} - 1 ))
done
dd if=/dev/random of=saved-entropy.1 bs=${entropy_save_sz} count=1 2>/dev/null
exit 0