1#!/bin/sh
2# demonstrate that tail -F works for currently missing dirs
3# Before coreutils-8.6, tail -F missing/file would not
4# notice any subsequent availability of the missing/file.
5
6# Copyright (C) 2010-2023 Free Software Foundation, Inc.
7
8# This program is free software: you can redistribute it and/or modify
9# it under the terms of the GNU General Public License as published by
10# the Free Software Foundation, either version 3 of the License, or
11# (at your option) any later version.
12
13# This program is distributed in the hope that it will be useful,
14# but WITHOUT ANY WARRANTY; without even the implied warranty of
15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16# GNU General Public License for more details.
17
18# You should have received a copy of the GNU General Public License
19# along with this program.  If not, see <https://www.gnu.org/licenses/>.
20
21. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
22print_ver_ tail
23
24check_tail_output()
25{
26  local delay="$1"
27  grep "$tail_re" out > /dev/null ||
28    { sleep $delay; return 1; }
29}
30
31# Terminate any background tail process
32cleanup_() { kill $pid 2>/dev/null && wait $pid; }
33
34# Speedup the non inotify case
35fastpoll='-s.1 --max-unchanged-stats=1'
36
37for mode in '' '---disable-inotify'; do
38  rm -rf out missing
39
40  tail $mode -F $fastpoll missing/file > out 2>&1 & pid=$!
41
42  # Wait up to 12.7s for tail to start with diagnostic:
43  # tail: cannot open 'missing/file' for reading: No such file or directory
44  tail_re='cannot open' retry_delay_ check_tail_output .1 7 ||
45    { cat out; fail=1; }
46
47  mkdir missing || framework_failure_
48  (cd missing && echo x > file) || framework_failure_
49
50  # Wait up to 12.7s for this to appear in the output:
51  # "tail: '...' has appeared;  following new file"
52  tail_re='has appeared' retry_delay_ check_tail_output .1 7 ||
53    { echo "$0: file: unexpected delay?"; cat out; fail=1; }
54
55  cleanup_
56done
57
58
59Exit $fail
60