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|
#!/bin/sh
# ensure that tail -F doesn't leak inotify resources
# Copyright (C) 2015-2023 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 <https://www.gnu.org/licenses/>.
. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ tail
# Inotify not used on remote file systems
require_local_dir_
grep '^#define HAVE_INOTIFY 1' "$CONFIG_HEADER" >/dev/null \
|| skip_ 'inotify required'
require_strace_ 'inotify_add_watch,inotify_rm_watch'
check_tail_output()
{
local delay="$1"
grep "$tail_re" out > /dev/null ||
{ sleep $delay; return 1; }
}
# Wait up to 25.5 seconds for grep REGEXP 'out' to succeed.
grep_timeout() { tail_re="$1" retry_delay_ check_tail_output .1 8; }
check_strace()
{
local delay="$1"
grep "$strace_re" strace.out > /dev/null ||
{ sleep $delay; return 1; }
}
cleanup_fail()
{
cat out
warn_ $1
fail=1
}
# Terminate any background tail process
cleanup_() { kill $pid 2>/dev/null && wait $pid; }
fastpoll='-s.1 --max-unchanged-stats=1'
touch k || framework_failure_
# Note the timeout guard isn't strictly necessary here,
# however without it strace will ignore SIGTERM.
# strace does always honor SIGTERM with the -I2 option,
# though that's not available on RHEL6 for example.
timeout 180 strace -e inotify_add_watch,inotify_rm_watch -o strace.out \
tail -F $fastpoll k >> out 2>&1 & pid=$!
reverted_to_polling_=0
for i in $(seq 2); do
echo $i
echo 'tailed' > k;
# Wait for watch on (new) file
strace_re='inotify_add_watch.*MODIFY' retry_delay_ check_strace .1 8 ||
no_watch_=1
# Assume this is not because we're leaking
# (resources may already be depleted)
# The explicit check for inotify_rm_watch should confirm that.
grep -F 'reverting to polling' out >/dev/null && skip_ 'inotify unused'
# Otherwise failure is unknown
test "$no_watch_" && { cat out; framework_failure_ 'no inotify_add_watch'; }
mv k k.tmp
# wait for tail to detect the rename
grep_timeout 'inaccessible' ||
{ cleanup_fail 'failed to detect rename'; break; }
# Note we strace here rather than consuming all available watches
# to be more efficient, but more importantly avoid depleting resources.
# Note also available resources can currently be tuned with:
# sudo sysctl -w fs.inotify.max_user_watches=$smallish_number
# However that impacts all processes for the current user, and also
# may not be supported in future, instead being auto scaled to RAM
# like the Linux epoll resources were.
if test "$i" -gt 1; then
strace_re='inotify_rm_watch' retry_delay_ check_strace .1 8 ||
{ cleanup_fail 'failed to find inotify_rm_watch syscall'; break; }
fi
>out && >strace.out || framework_failure_ 'failed to reset output files'
done
cleanup_
Exit $fail
|
