| #! /bin/sh |
| # |
| # urandom This script saves the random seed between reboots. |
| # It is called from the boot, halt and reboot scripts. |
| # |
| # Version: @(#)urandom 1.33 22-Jun-1998 miquels@cistron.nl |
| # |
| |
| [ -c /dev/urandom ] || exit 0 |
| #. /etc/default/rcS |
| |
| case "$1" in |
| start|"") |
| # check for read only file system |
| if ! touch /etc/random-seed 2>/dev/null |
| then |
| echo "read-only file system detected...done" |
| exit |
| fi |
| if [ "$VERBOSE" != no ] |
| then |
| printf "Initializing random number generator... " |
| fi |
| # Load and then save 512 bytes, |
| # which is the size of the entropy pool |
| cat /etc/random-seed >/dev/urandom |
| rm -f /etc/random-seed |
| umask 077 |
| dd if=/dev/urandom of=/etc/random-seed count=1 \ |
| >/dev/null 2>&1 || echo "urandom start: failed." |
| umask 022 |
| [ "$VERBOSE" != no ] && echo "done." |
| ;; |
| stop) |
| if ! touch /etc/random-seed 2>/dev/null |
| then |
| exit |
| fi |
| # Carry a random seed from shut-down to start-up; |
| # see documentation in linux/drivers/char/random.c |
| [ "$VERBOSE" != no ] && printf "Saving random seed... " |
| umask 077 |
| dd if=/dev/urandom of=/etc/random-seed count=1 \ |
| >/dev/null 2>&1 || echo "urandom stop: failed." |
| [ "$VERBOSE" != no ] && echo "done." |
| ;; |
| *) |
| echo "Usage: urandom {start|stop}" >&2 |
| exit 1 |
| ;; |
| esac |
