#!/bin/bash

# This file is part of util-linux.
#
# This file 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 2 of the License, or
# (at your option) any later version.
#
# This file 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.

TS_TOPDIR="${0%/*}/../.."
TS_DESC="flock"

. $TS_TOPDIR/functions.sh
ts_init "$*"

ts_check_test_command "$TS_CMD_FLOCK"
ts_check_prog "pgrep"
ts_check_prog "timeout"


function do_lock {
	local opts="$1"
	local expected_rc="$2"
	local mesg="$3"

	$TS_CMD_FLOCK $1 $TS_OUTDIR/lockfile \
		echo "$mesg" \
		> $TS_OUTPUT 2>&1

	local rc="$?"

	if [  "$rc" == "$expected_rc" ]; then
		ts_log "Success"
	else
		ts_log "Failed [rc=$rc]"
	fi
}

# general lock
GEN_OUTPUT="$TS_OUTPUT"
START=$(date '+%s')
# running flock in background is not the best usage example
$TS_CMD_FLOCK --shared $TS_OUTDIR/lockfile \
	bash -c 'echo "Locking"; sleep 3; echo "Unlocking"' \
	> $GEN_OUTPUT 2>&1 &
pid=$!

# check for running background process
if [ "$pid" -le "0" ] || ! kill -s 0 "$pid" &>/dev/null; then
	ts_die "unable to run flock"
fi
# the lock should be established when flock has a child
timeout 1s bash -c "while ! pgrep -P $pid >/dev/null; do sleep 0.1 ;done" \
	|| ts_die "timeout waiting for flock child"

ts_init_subtest "non-block"
do_lock "--nonblock --conflict-exit-code 123" 123 "You will never see this!"
ts_finalize_subtest


ts_init_subtest "no-fork"
do_lock "--no-fork --nonblock --conflict-exit-code 123" 123 "You will never see this!"
ts_finalize_subtest


ts_init_subtest "shared"
do_lock "--shared" 0 "Have shared lock"
ts_finalize_subtest


# this is the same as non-block test (exclusive lock is the default), but here
# we explicitly specify --exclusive on command line
ts_init_subtest "exclusive"
do_lock "--nonblock --exclusive --conflict-exit-code 123" 123 "You will never see this!"
ts_finalize_subtest


ts_init_subtest "timeout"
do_lock "--timeout 5 --conflict-exit-code 5" 0 "After timeout."
END=$(date '+%s')
ts_finalize_subtest


# expected is 3 seconds (see "sleep 3" for the general lock), but we should not
# rely on exact number due to scheduler, machine load, etc. Let's check for
# inmterval <3,5>.
# 
ts_init_subtest "time-check"
TIMEDIFF=$(( $END - $START ))
if [ $TIMEDIFF -lt 3 ]; then
	ts_log "general lock failed [$TIMEDIFF sec]"
elif [ $TIMEDIFF -gt 5 ]; then
	ts_log "wait too long [$TIMEDIFF sec]"
else
	ts_log "success"
fi
ts_finalize_subtest "diff ${TIMEDIFF} sec"


echo "Unlocked" >> $GEN_OUTPUT 
ts_finalize