source: kBuild/trunk/src/grep/tests/in-eq-out-infloop

#!/bin/sh
# Demonstrate the disk-filling infloop when redirecting to an input file.
. "${srcdir=.}/init.sh"; path_prepend_ ../src
require_timeout_

# Use an input file large enough that the problem is reproducible in spite
# of buffering effects.  Just larger than 256KB should be adequate.
v=$(printf %063d 0)'
'
# 64 * 2^12 = 256k
for i in 1 2 3 4 5 6 7 8 9 10 11 12; do
  v="$v$v"
done

echo "$v" > out || framework_failure_

for arg in out - ''; do
  # Accommodate both 'out' and '(standard input)', as well as
  # the multi-byte quoting we see on OS/X-based systems.
  echo grep: ...: input file is also the output > err.exp || framework_failure_

  # Require an exit status of 2.
  # grep-2.8 and earlier would infloop with $arg = out.
  # grep-2.10 and earlier would infloop with $arg = - or $arg = ''.
  timeout 10 grep 0 $arg < out >> out 2> err; st=$?; test $st = 2 || fail=1
  sed 's/grep: .*: /grep: ...: /' err > k && mv k err
  # Normalize the diagnostic prefix from e.g., "/mnt/dir/grep: " to "grep: "
  sed 's/^[^:]*: /grep: /' err > k && mv k err
  compare err.exp err || fail=1

  # But with each of the following options it must not exit-2.
  for i in -q -m1 -l -L; do
    timeout 10 grep $i 0 $arg < out >> out 2> err; st=$?
    test $st = 2 && fail=1
  done

  timeout 10 grep -2 0 $arg < out >> out 2> err; st=$?
  test $st = 2 || fail=1
done

Exit $fail