1#!/bin/sh
2# Exercise an abort-inducing flaw in inotify-enabled tail -F.
3
4# Copyright (C) 2009-2023 Free Software Foundation, Inc.
5
6# This program is free software: you can redistribute it and/or modify
7# it under the terms of the GNU General Public License as published by
8# the Free Software Foundation, either version 3 of the License, or
9# (at your option) any later version.
10
11# This program is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14# GNU General Public License for more details.
15
16# You should have received a copy of the GNU General Public License
17# along with this program.  If not, see <https://www.gnu.org/licenses/>.
18
19. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
20print_ver_ tail
21
22# 9 is a magic number, related to internal details of tail.c and hash.c
23n=9
24seq $n | xargs touch || framework_failure_
25
26check_tail_output()
27{
28  local delay="$1"
29  grep "$tail_re" out > /dev/null ||
30    { sleep $delay; return 1; }
31}
32
33# Terminate any background tail process
34cleanup_() { kill $pid 2>/dev/null && wait $pid; }
35
36# Speedup the non inotify case
37fastpoll='-s.1 --max-unchanged-stats=1'
38
39for mode in '' '---disable-inotify'; do
40  rm -f out
41
42  tail $mode $fastpoll -qF $(seq $n) > out 2>&1 & pid=$!
43
44  # Wait up to 12.7s for tail to start
45  echo x > $n
46  tail_re='^x$' retry_delay_ check_tail_output .1 7 ||
47    { cat out; fail=1; }
48
49  mv 1 f || framework_failure_
50
51  # Wait 12.7s for this diagnostic:
52  # tail: '1' has become inaccessible: No such file or directory
53  tail_re='inaccessible' retry_delay_ check_tail_output .1 7 ||
54    { cat out; fail=1; }
55
56  # Trigger the bug.  Before the fix, this would provoke the abort.
57  echo a > 1 || framework_failure_
58
59  # Wait up to 6.3s for the "tail: '1' has appeared; ..." message
60  # (or for the buggy tail to die)
61  tail_re='has appeared' retry_delay_ check_tail_output .1 6 ||
62    { cat out; fail=1; }
63
64  # Double check that tail hasn't aborted
65  kill -0 $pid || fail=1
66
67  cleanup_
68done
69
70
71Exit $fail
72