tests/dd/no-allocate.sh

   1 #!/bin/sh
   2 # make sure that dd doesn't allocate memory unnecessarily
   3
   4 # Copyright (C) 2013-2015 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 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  20 print_ver_ dd
  21 require_ulimit_v_
  22
  23 # count and skip are zero, we don't need to allocate memory
  24 (ulimit -v 20000; dd  bs=30M count=0) || fail=1
  25 (ulimit -v 20000; dd ibs=30M count=0) || fail=1
  26 (ulimit -v 20000; dd obs=30M count=0) || fail=1
  27
  28 check_dd_seek_alloc() {
  29   local file="$1"
  30   local buf="$2"
  31   test "$file" = 'in' && { dd_file=if; dd_op=skip; }
  32   test "$file" = 'out' && { dd_file=of; dd_op=seek; }
  33   test "$buf" = 'in' && { dd_buf=ibs; }
  34   test "$buf" = 'out' && { dd_buf=obs; }
  35   test "$buf" = 'both' && { dd_buf=bs; }
  36
  37   # Provide input to the "tape"
  38   timeout 10 dd count=1 if=/dev/zero of=tape&
  39
  40   # Allocate buffer and read from the "tape"
  41   (ulimit -v 20000; timeout 10 dd $dd_buf=30M $dd_op=1 count=0 $dd_file=tape)
  42   local ret=$?
  43
  44   # Be defensive in case the tape reader is blocked for some reason
  45   test $ret = 124 && framework_failure_
  46
  47   # This should happen without delay,
  48   # and is used to ensure we've not multiple writers to the "tape"
  49   wait
  50
  51   # We want the "tape" reader to fail iff allocating
  52   # a large buffer corresponding to the file being read
  53   case "$file$buf" in
  54     inout|outin) test $ret = 0;;
  55     *) test $ret != 0;;
  56   esac
  57 }
  58
  59 # Use a fifo for which seek fails, but read does not.
  60 # For non seekable output we need to allocate a buffer
  61 # when simulating seeking with a read.
  62 if mkfifo tape; then
  63   for file in 'in' 'out'; do
  64     for buf in 'both' 'in' 'out'; do
  65       check_dd_seek_alloc "$file" "$buf" || fail=1
  66     done
  67   done
  68 fi
  69
  70 Exit $fail