tests/tail-2/big-4gb

   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 . $srcdir/../expensive
   6
   7 if test "$VERBOSE" = yes; then
   8   set -x
   9   tail --version
  10 fi
  11
  12 pwd=`pwd`
  13 t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
  14 trap 'status=$?; cd $pwd; chmod -R u+rwx $t0; rm -rf $t0 && exit $status' 0
  15 trap '(exit $?); exit $?' 1 2 13 15
  16
  17 framework_failure=0
  18 mkdir -p $tmp || framework_failure=1
  19 cd $tmp || framework_failure=1
  20
  21 # Create a file of size exactly 4GB (2^32) with 8 bytes
  22 # at the beginning and another set of 8 bytes at the end.
  23 # The rest will be NUL bytes.  On most modern systems, the following
  24 # creates a file that takes up only a few KB.  Here, du -sh says 16K.
  25 echo abcdefgh | tr -d '\n' > big || framework_failure=1
  26 echo 87654321 | tr -d '\n' > tmp || framework_failure=1
  27 # Seek 4GB - 8
  28 dd bs=1 seek=4294967288 if=tmp of=big 2> err || dd_failed=1
  29 if test "$dd_failed" = 1; then
  30   cat err 1>&2
  31   echo "$0: cannot create a file large enough for this test," 1>&2
  32   echo "$0: possibly because this system doesn't support large files;" 1>&2
  33   echo "$0: Consider rerunning this test on a different file system." 1>&2
  34   (exit 77); exit 77
  35 fi
  36
  37 if test $framework_failure = 1; then
  38   echo "$0: failure in testing framework" 1>&2
  39   (exit 1); exit 1
  40 fi
  41
  42 fail=0
  43
  44 tail -c1 big > out || fail=1
  45 # Append a newline.
  46 echo >> out
  47 cat <<\EOF > exp
  48 1
  49 EOF
  50
  51 cmp out exp || fail=1
  52 test $fail = 1 && diff out exp 2> /dev/null
  53
  54 (exit $fail); exit $fail