tests/dd/no-allocate.sh

   1 #!/bin/sh
   2 # make sure that dd doesn't allocate memory unnecessarily
   3
   4 # Copyright (C) 2013-2016 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 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  20 print_ver_ dd
  21
  22 # Determine basic amount of memory needed.
  23 echo . > f || framework_failure_
  24 vm=$(get_min_ulimit_v_ timeout 10 dd if=f of=f2 status=none) \
  25   || skip_ "this shell lacks ulimit support"
  26 rm f f2 || framework_failure_
  27
  28 # count and skip are zero, we don't need to allocate memory
  29 (ulimit -v $vm && dd  bs=30M count=0) || fail=1
  30 (ulimit -v $vm && dd ibs=30M count=0) || fail=1
  31 (ulimit -v $vm && dd obs=30M count=0) || fail=1
  32
  33 check_dd_seek_alloc() {
  34   local file="$1"
  35   local buf="$2"
  36   test "$file" = 'in' && { dd_file=if; dd_op=skip; }
  37   test "$file" = 'out' && { dd_file=of; dd_op=seek; }
  38   test "$buf" = 'in' && { dd_buf=ibs; }
  39   test "$buf" = 'out' && { dd_buf=obs; }
  40   test "$buf" = 'both' && { dd_buf=bs; }
  41
  42   # Provide input to the "tape"
  43   timeout 10 dd count=1 if=/dev/zero of=tape&
  44
  45   # Allocate buffer and read from the "tape"
  46   (ulimit -v $vm \
  47      && timeout 10 dd $dd_buf=30M $dd_op=1 count=0 $dd_file=tape)
  48   local ret=$?
  49
  50   # Be defensive in case the tape reader is blocked for some reason
  51   test $ret = 124 && framework_failure_
  52
  53   # This should happen without delay,
  54   # and is used to ensure we've not multiple writers to the "tape"
  55   wait
  56
  57   # We want the "tape" reader to fail iff allocating
  58   # a large buffer corresponding to the file being read
  59   case "$file$buf" in
  60     inout|outin) test $ret = 0;;
  61     *) test $ret != 0;;
  62   esac
  63 }
  64
  65 # Use a fifo for which seek fails, but read does not.
  66 # For non seekable output we need to allocate a buffer
  67 # when simulating seeking with a read.
  68 if mkfifo tape; then
  69   for file in 'in' 'out'; do
  70     for buf in 'both' 'in' 'out'; do
  71       check_dd_seek_alloc "$file" "$buf" || fail=1
  72     done
  73   done
  74 fi
  75
  76 Exit $fail