#!/bin/sh
# demonstrate that tail -F works for currently missing dirs
# Before coreutils-8.6, tail -F missing/file would not
# notice any subsequent availability of the missing/file.

# Copyright (C) 2010-2014 Free Software Foundation, Inc.

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ tail

debug='---disable-inotify'
debug=
tail $debug -F -s.1 missing/file > out 2>&1 & pid=$!

check_tail_output()
{
  local delay="$1"
  grep "$tail_re" out > /dev/null ||
    { sleep $delay; return 1; }
}

# Wait up to 6.3s for tail to start with diagnostic:
# tail: cannot open 'missing/file' for reading: No such file or directory
tail_re='cannot open' retry_delay_ check_tail_output .1 7 || fail=1

mkdir missing || fail=1
(cd missing && echo x > file)

# Wait up to 6.3s for this to appear in the output:
# "tail: '...' has appeared;  following end of new file"
tail_re='has appeared' retry_delay_ check_tail_output .1 7 ||
  { echo "$0: file: unexpected delay?"; cat out; fail=1; }

kill -HUP $pid

cleanup()
{
  local delay="$1"
  rm -rf missing ||
    { sleep $delay; return 1; }
}

# Try repeatedly to remove the temporary directory.
# This is normally unnecessary, because the containing directory will
# be removed by code from init.sh.  However, when this particular test
# is run on an NFS-mounted volume, sometimes init.sh's cleanup code
# fails because the directory is not yet really empty, perhaps because
# the tail process (reading missing/file) is not yet killed.
retry_delay_ cleanup .1 6

Exit $fail
