tests/tail/F-vs-missing.sh

   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) 2010-2024 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
  22 print_ver_ tail
  23
  24 check_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
  32 cleanup_() { kill $pid 2>/dev/null && wait $pid; }
  33
  34 # Speedup the non inotify case
  35 fastpoll='-s.1 --max-unchanged-stats=1'
  36
  37 for 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_
  56 done
  57
  58
  59 Exit $fail