tests/tail-2/inotify-race.sh

   1 #!/bin/sh
   2 # Ensure that tail does not ignore data that is appended to a tailed-forever
   3 # file between tail's initial read-to-EOF, and when the inotify watches
   4 # are established in tail_forever_inotify.  That data could be ignored
   5 # indefinitely if no *other* data is appended, but it would be printed as
   6 # soon as any additional appended data is detected.
   7
   8 # Copyright (C) 2009-2016 Free Software Foundation, Inc.
   9
  10 # This program is free software: you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation, either version 3 of the License, or
  13 # (at your option) any later version.
  14
  15 # This program is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19
  20 # You should have received a copy of the GNU General Public License
  21 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
  24 print_ver_ tail sleep
  25
  26 # Terminate any background gdb/tail process
  27 cleanup_() {
  28   kill $pid 2>/dev/null && wait $pid
  29   kill $sleep 2>/dev/null && wait $sleep
  30 }
  31
  32 touch file || framework_failure_
  33 touch tail.out || framework_failure_
  34
  35 ( timeout 10s gdb --version ) > gdb.out 2>&1
  36 case $(cat gdb.out) in
  37     *'GNU gdb'*) ;;
  38     *) skip_ "can't run gdb";;
  39 esac
  40
  41 # Break on a line rather than a symbol, to cater for inline functions
  42 break_src="$abs_top_srcdir/src/tail.c"
  43 break_line=$(grep -n ^tail_forever_inotify "$break_src") || framework_failure_
  44 break_line=$(echo "$break_line" | cut -d: -f1) || framework_failure_
  45
  46
  47 # Note we get tail to monitor a background sleep process
  48 # rather than using timeout(1), as timeout sends SIGCONT
  49 # signals to its monitored process, and gdb (7.9 at least)
  50 # has _intermittent_ issues with this.
  51 # Sending SIGCONT resulted in either delayed child termination,
  52 # or no child termination resulting in a hung test.
  53 # See https://sourceware.org/bugzilla/show_bug.cgi?id=18364
  54
  55 env sleep 10 & sleep=$!
  56
  57 # See if gdb works and
  58 # tail_forever_inotify is compiled and run
  59 gdb -nx --batch-silent \
  60     --eval-command="break $break_line"             \
  61     --eval-command="run --pid=$sleep -f file"      \
  62     --eval-command='quit'                          \
  63     tail < /dev/null > gdb.out 2>&1
  64
  65 kill $sleep || skip_ 'breakpoint not hit'
  66 wait $sleep
  67
  68 # FIXME: The above is seen to _intermittently_ fail with:
  69 # warning: .dynamic section for "/lib/libc.so.6" is not at the expected address
  70 # warning: difference appears to be caused by prelink, adjusting expectations
  71 compare /dev/null gdb.out || skip_ "can't set breakpoints in tail"
  72
  73 env sleep 10 & sleep=$!
  74
  75 # Run "tail -f file", stopping to append a line just before
  76 # inotify initialization, and then continue.  Before the fix,
  77 # that just-appended line would never be output.
  78 gdb -nx --batch-silent \
  79     --eval-command="break $break_line"             \
  80     --eval-command="run --pid=$sleep -f file >> tail.out"       \
  81     --eval-command='shell echo never-seen-with-tail-7.5 >> file' \
  82     --eval-command='continue'                      \
  83     --eval-command='quit'                          \
  84     tail < /dev/null > /dev/null 2>&1 & pid=$!
  85
  86 tail --pid=$pid -f tail.out | (read REPLY; kill $pid)
  87
  88 # gdb has a bug in Debian's gdb-6.8-3 at least that causes it to not
  89 # cleanup and exit correctly when it receives a SIGTERM, but
  90 # killing sleep, should cause the tail process and thus gdb to exit.
  91 kill $sleep
  92 wait $sleep
  93
  94 wait $pid
  95
  96 compare /dev/null tail.out && fail=1
  97
  98 Exit $fail