aboutsummaryrefslogtreecommitdiff
path: root/init.d/urandom
blob: 3d0837667f5cab45fe5630cad1e8e3ae1c46714a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
#!/sbin/runscript
# Copyright 1999-2007 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

URANDOM_SEED=${URANDOM_SEED:-/var/run/random-seed}

description="Initializes the random number generator."

depend() {
	need localmount
}

save_seed() {
	local poolsize=1

	if [ -e /proc/sys/kernel/random/poolsize ] ; then
		poolsize=$(($(cat /proc/sys/kernel/random/poolsize) / 4096))
	fi

	(	# sub shell to prevent umask pollution
		umask 077
		dd if=/dev/urandom of="${URANDOM_SEED}" count=${poolsize} 2>/dev/null
	)
}

start() {
	[ -c /dev/urandom ] || return
	if [ -f "${URANDOM_SEED}" ] ; then
		cat "${URANDOM_SEED}" > /dev/urandom
	fi
	if ! rm -f "${URANDOM_SEED}" ; then
		ewarn "Skipping ${URANDOM_SEED} initialization (ro root?)"
		return 0
	fi
	ebegin "Initializing random number generator"
	save_seed
	eend $? "Error initializing random number generator"
}

stop() {
	ebegin "Saving random seed"
	# Carry a random seed from shut-down to start-up;
	# see documentation in linux/drivers/char/random.c
	save_seed
	eend $? "Failed to save random seed"
}

# vim: set ts=4 :