mdw@git.distorted.org.uk Git - profile/blob - bin/check-blkdev-size

   1 #! /bin/bash
   2
   3 set -e -o pipefail
   4
   5 case $# in 1) ;; *) echo >&2 "usage: $0 DEV"; exit 127 ;; esac
   6 dev=$1
   7
   8 typeset -i sz; sz=$(blockdev --getsize64 "$dev")
   9 k=$(gorp -fhex 256)
  10
  11 ## Figure out a useful block size.
  12 typeset -i bsz=1 nb=$sz
  13 for i in 2 3 5 7; do
  14   while :; do
  15     case $((nb%i)) in
  16       0) bsz=$((bsz*i)) nb=$((nb/i)) ;;
  17       *) break ;;
  18     esac
  19     if (( bsz >= 65536 )); then break 2; fi
  20   done
  21 done
  22 echo >&2 "$0: using $nb blocks of size $bsz"
  23
  24 ## Write the initial stream.
  25 echo >&2 "$0: writing pseudorandom pattern..."
  26 rspit salsa20/8 -H$k -z$sz -pT | \
  27   dd status=none iflag=fullblock oflag=direct bs=$bsz count=$nb of="$dev"
  28 echo >&2 "$0: writing pseudorandom pattern... done"
  29
  30 ## Read the stream back, and check against the reference.
  31 echo >&2 "$0: checking pseudorandom pattern..."
  32 cmp <(rspit salsa20/8 -H$k -z$sz -pT) \
  33     <(dd status=none iflag=direct bs=$bsz count=$nb if="$dev")
  34 echo >&2 "$0: checking pseudorandom pattern... done"
  35 echo >&2 "$0: all ok"