package/initscripts/init.d/S20urandom

   1 #! /bin/sh
   2 #
   3 # urandom       This script saves the random seed between reboots.
   4 #               It is called from the boot, halt and reboot scripts.
   5 #
   6 # Version:      @(#)urandom  1.33  22-Jun-1998  miquels@cistron.nl
   7 #
   8
   9 [ -c /dev/urandom ] || exit 0
  10 #. /etc/default/rcS
  11
  12 case "$1" in
  13         start|"")
  14                 # check for read only file system
  15                 if ! touch /etc/random-seed 2>/dev/null
  16                 then
  17                         echo "read-only file system detected...done"
  18                         exit
  19                 fi
  20                 if [ "$VERBOSE" != no ]
  21                 then
  22                         printf "Initializing random number generator... "
  23                 fi
  24                 # Load and then save 512 bytes,
  25                 # which is the size of the entropy pool
  26                 cat /etc/random-seed >/dev/urandom
  27                 rm -f /etc/random-seed
  28                 umask 077
  29                 dd if=/dev/urandom of=/etc/random-seed count=1 \
  30                         >/dev/null 2>&1 || echo "urandom start: failed."
  31                 umask 022
  32                 [ "$VERBOSE" != no ] && echo "done."
  33                 ;;
  34         stop)
  35                 if ! touch /etc/random-seed 2>/dev/null
  36                 then
  37                         exit
  38                 fi
  39                 # Carry a random seed from shut-down to start-up;
  40                 # see documentation in linux/drivers/char/random.c
  41                 [ "$VERBOSE" != no ] && printf "Saving random seed... "
  42                 umask 077
  43                 dd if=/dev/urandom of=/etc/random-seed count=1 \
  44                         >/dev/null 2>&1 || echo "urandom stop: failed."
  45                 [ "$VERBOSE" != no ] && echo "done."
  46                 ;;
  47         *)
  48                 echo "Usage: urandom {start|stop}" >&2
  49                 exit 1
  50                 ;;
  51 esac