NetBSD/etc/rc.d/random_seed

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#!/bin/sh
#
# $NetBSD: random_seed,v 1.15 2020/09/08 12:52:18 martin Exp $
#
# PROVIDE: random_seed
# REQUIRE: CRITLOCALMOUNTED
# BEFORE: securelevel
# BEFORE: bootconf
# KEYWORD: shutdown
#
# The "BEFORE: securelevel" is a real dependency, in that
# this script won't work if run after the securelevel is changed.
#
# The "BEFORE: bootconf" is intended to cause this to
# be the first script that runs after mountcritlocal.
$_rc_subr_loaded . /etc/rc.subr
name="random_seed"
rcvar=$name
start_cmd="random_load"
stop_cmd="random_save"
random_file="${random_file:-/var/db/entropy-file}"
message()
{
echo "${name}: ${random_file}: $@" 1>&2
}
fs_safe()
{
# Consider the root file system safe always.
df -P "$1" | (while read dev total used avail cap mountpoint; do
case $mountpoint in
'Mounted on') continue;;
/) exit 0;;
*) exit 1;;
esac
done) && return 0
# Otherwise, consider local file systems safe and non-local
# file systems unsafe.
case $(df -l "$1") in
*Warning:*)
return 1
;;
*)
return 0
;;
esac
}
random_load()
{
local flags=
if [ ! -f "${random_file}" ]; then
message "Not present; creating"
random_save
return
fi
if ! fs_safe "${random_file}"; then
message "Unsafe file system"
flags=-i
fi
set -- $(ls -ldn "${random_file}")
st_mode="$1" # should be "-rw-------"
st_uid="$3" # should be "0" for root
# The file must be owned by root,
if [ "$st_uid" != "0" ]; then
message "Bad owner ${st_uid}"
flags=-i
fi
# and root read/write only.
if [ "$st_mode" != "-rw-------" ]; then
message "Bad mode ${st_mode}"
flags=-i
fi
if rndctl $flags -L "${random_file}"; then
echo "Loaded entropy from ${random_file}."
fi
}
random_save()
{
oum="$(umask)"
umask 077
if rndctl -S "${random_file}"; then
echo "Saved entropy to ${random_file}."
fi
umask "${oum}"
}
load_rc_config "${name}"
run_rc_command "$1"