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#!/bin/sh
# ensure that tail -F handles rotation
# Copyright (C) 2009-2011 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 <http://www.gnu.org/licenses/>.
if test "$VERBOSE" = yes; then
set -x
tail --version
fi
. "${srcdir=.}/init.sh"; path_prepend_ ../src
expensive_
# Wait several seconds for grep REGEXP FILE to succeed.
# Usage: grep_timeout REGEXP FILE
grep_timeout()
{
local j
for j in $(seq 150); do
grep $1 $2 > /dev/null && return 0
sleep 0.1
done
return 1
}
# For details, see
# http://lists.gnu.org/archive/html/bug-coreutils/2009-11/msg00213.html
# Perform at least this many iterations, because on multi-core systems
# the offending sequence of events can be surprisingly uncommon.
for i in $(seq 50); do
echo $i
rm -rf k x out
# Normally less than a second is required here, but with heavy load
# and a lot of disk activity, even 20 seconds is insufficient, which
# leads to this timeout killing tail before the "ok" is written below.
:>k && :>x && timeout 40 tail -F k > out 2>&1 &
pid=$!
sleep .1
echo b > k;
# wait for b to appear in out
grep_timeout b out || fail_ failed to find b in out
while :; do grep b out > /dev/null && break; done
mv x k
# wait for tail to detect the rename
grep_timeout tail: out || { cat out; fail_ failed to detect rename; }
echo ok >> k
found=0
# wait up to 10 seconds for "ok" to appear in out
grep_timeout ok out && found=1
kill $pid
test $found = 0 && { cat out; fail_ failed to detect echoed '"ok"'; }
done
Exit $fail
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