tests/dd/reblock

   1 #!/bin/sh
   2 # test dd reblocking vs. bs=
   3
   4 # Copyright (C) 2008-2010 Free Software Foundation, Inc.
   5
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 if test "$VERBOSE" = yes; then
  20   set -x
  21   dd --version
  22 fi
  23
  24 . $srcdir/test-lib.sh
  25
  26 # 2 short reads -> 1 full write + 1 partial write
  27 cat <<\EOF > exp-reblock || framework_failure
  28 0+2 records in
  29 1+1 records out
  30 4 bytes (4 B) copied
  31 EOF
  32
  33 # 2 short reads -> 2 partial writes
  34 cat <<\EOF > exp-no-reblock || framework_failure
  35 0+2 records in
  36 0+2 records out
  37 4 bytes (4 B) copied
  38 EOF
  39
  40
  41 # Use a fifo rather than a pipe in the tests below
  42 # so that the producer (printf subshell) will wait
  43 # until the consumer (dd) opens the fifo therefore
  44 # increasing the chance that dd will read the data
  45 # from each printf separately.
  46 mkfifo dd.fifo || framework_failure
  47
  48 dd_reblock_1()
  49 {
  50   local delay="$1"
  51
  52   # ensure that dd reblocks when bs= is not specified
  53   dd ibs=3 obs=3 if=dd.fifo > out 2> err&
  54   (printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
  55   wait #for dd to complete
  56   sed 's/,.*//' err > k && mv k err
  57   compare err exp-reblock
  58 }
  59
  60 retry_delay_ dd_reblock_1 .1 6 || fail=1
  61
  62 dd_reblock_2()
  63 {
  64   local delay="$1"
  65
  66   # Demonstrate that bs=N supersedes even following ibs= and obs= settings.
  67   dd bs=3 ibs=1 obs=1 if=dd.fifo > out 2> err&
  68   (printf 'ab'; sleep $delay; printf 'cd') > dd.fifo
  69   wait #for dd to complete
  70   sed 's/,.*//' err > k && mv k err
  71   compare err exp-no-reblock
  72 }
  73
  74 retry_delay_ dd_reblock_2 .1 6 || fail=1
  75
  76 Exit $fail