tests/tail/big-4gb.sh

   1 #!/bin/sh
   2 # Demonstrate a bug in 'tail -cN' when operating on files of size 4G and larger
   3 # Fixed in coreutils-4.5.2.
   4
   5 # Copyright (C) 2002-2024 Free Software Foundation, Inc.
   6
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19
  20 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  21 print_ver_ tail
  22 expensive_
  23
  24 # Create a file of size exactly 4GB (2^32) with 8 bytes
  25 # at the beginning and another set of 8 bytes at the end.
  26 # The rest will be NUL bytes.  On most modern systems, the following
  27 # creates a file that takes up only a few KB.  Here, du -sh says 16K.
  28 echo abcdefgh | tr -d '\n' > big || framework_failure_
  29 echo 87654321 | tr -d '\n' > tmp || framework_failure_
  30 # Seek 4GB - 8
  31 dd bs=1 seek=4294967288 if=tmp of=big 2> err || dd_failed=1
  32 if test "$dd_failed" = 1; then
  33   cat err 1>&2
  34   skip_ \
  35 'cannot create a file large enough for this test,
  36 possibly because this system does not support large files;
  37 Consider rerunning this test on a different file system.'
  38 fi
  39
  40
  41 tail -c1 big > out || fail=1
  42 # Append a newline.
  43 echo >> out
  44 cat <<\EOF > exp
  45 1
  46 EOF
  47
  48 compare exp out || fail=1
  49
  50 Exit $fail