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