xref: /src/tests/sys/kern/timerfd.c (revision 4b16ff49bf4bf875997fe4c80a0afc0d440b7aac)

/*-
 * SPDX-License-Identifier: MIT
 *
 * Copyright (c) 2016 Jan Kokemüller
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <atf-c.h>

#include <sys/types.h>
#include <sys/event.h>
#include <sys/param.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/timerfd.h>

#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include <err.h>
#include <poll.h>
#include <pthread.h>
#include <time.h>
#include <unistd.h>

/* Time in ns that sleeps are allowed to take longer for in unit tests. */
#define TIMER_SLACK (90000000)

ATF_TC_WITHOUT_HEAD(timerfd__many_timers);
ATF_TC_BODY(timerfd__many_timers, tc)
{
	int timer_fds[256];
	int i;

	for (i = 0; i < (int)nitems(timer_fds); ++i) {
		timer_fds[i] = timerfd_create(CLOCK_MONOTONIC, /**/
		    TFD_CLOEXEC | TFD_NONBLOCK);
		if (timer_fds[i] < 0 && errno == EMFILE) {
			atf_tc_skip("timerfd_create: EMFILE");
		}
		ATF_REQUIRE_MSG(timer_fds[i] >= 0, "errno: %d", errno);
	}
}

static uint64_t
wait_for_timerfd(int timerfd)
{
	struct pollfd pfd = { .fd = timerfd, .events = POLLIN };

	ATF_REQUIRE(poll(&pfd, 1, -1) == 1);

	uint64_t timeouts;
	ssize_t r = read(timerfd, &timeouts, sizeof(timeouts));

	ATF_REQUIRE_MSG(r == (ssize_t)sizeof(timeouts), "%d %d", (int)r, errno);
	ATF_REQUIRE(timeouts > 0);
	return timeouts;
}

ATF_TC_WITHOUT_HEAD(timerfd__simple_timer);
ATF_TC_BODY(timerfd__simple_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	(void)wait_for_timerfd(timerfd);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);

	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 100000000) || e.tv_sec > 0);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec < 100000000 + TIMER_SLACK);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__simple_periodic_timer);
ATF_TC_BODY(timerfd__simple_periodic_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 200000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 200000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	uint64_t timeouts = wait_for_timerfd(timerfd);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);

	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 200000000) || e.tv_sec > 0);
	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec < 200000000 + TIMER_SLACK);
	ATF_REQUIRE(timeouts == 1);

	usleep(400000);

	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    (ssize_t)sizeof(timeouts));
	ATF_REQUIRE(timeouts >= 2);
	ATF_REQUIRE(timeouts == 2);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__complex_periodic_timer);
ATF_TC_BODY(timerfd__complex_periodic_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 200000001,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	uint64_t timeouts = wait_for_timerfd(timerfd);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);

	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 100000000) || e.tv_sec > 0);
	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE_MSG(e.tv_sec == 0 && e.tv_nsec >= 100000000 &&
		e.tv_nsec < 100000000 + TIMER_SLACK,
	    "%ld", (long)e.tv_nsec);
	ATF_REQUIRE(timeouts == 1);

	usleep(401000);

	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    (ssize_t)sizeof(timeouts));
	ATF_REQUIRE_MSG(timeouts >= 2, "%d", (int)timeouts);
	ATF_REQUIRE_MSG(timeouts == 2, "%d", (int)timeouts);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__reset_periodic_timer);
ATF_TC_BODY(timerfd__reset_periodic_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	(void)wait_for_timerfd(timerfd);

	time = (struct itimerspec) {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 50000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	uint64_t timeouts = wait_for_timerfd(timerfd);
	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE(timeouts == 1);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);
	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 150000000) || e.tv_sec > 0);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec >= 150000000 &&
	    e.tv_nsec < 150000000 + TIMER_SLACK * 2);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__reenable_periodic_timer);
ATF_TC_BODY(timerfd__reenable_periodic_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	uint64_t timeouts = wait_for_timerfd(timerfd);

	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE(timeouts == 1);

	time = (struct itimerspec) {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 0,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 0,
	};

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
	ATF_REQUIRE(poll(&pfd, 1, 250) == 0);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);

	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 350000000) || e.tv_sec > 0);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec >= 350000000 &&
	    e.tv_nsec < 350000000 + TIMER_SLACK * 2);

	time = (struct itimerspec) {
		.it_value.tv_sec = 1,
		.it_value.tv_nsec = 0,
		.it_interval.tv_sec = 1,
		.it_interval.tv_nsec = 0,
	};
	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	ATF_REQUIRE(close(timerfd) == 0);
}

/*
 * Adapted from sghctoma's example here:
 * https://github.com/jiixyj/epoll-shim/issues/2
 *
 * The SIGUSR1 signal should not kill the process.
 */
ATF_TC_WITHOUT_HEAD(timerfd__expire_five);
ATF_TC_BODY(timerfd__expire_five, tc)
{
	int fd;
	struct itimerspec value;
	uint64_t total_exp = 0;

	fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK);
	ATF_REQUIRE(fd >= 0);

	value.it_value.tv_sec = 3;
	value.it_value.tv_nsec = 0;
	value.it_interval.tv_sec = 1;
	value.it_interval.tv_nsec = 0;

	ATF_REQUIRE(timerfd_settime(fd, 0, &value, NULL) == 0);

	sigset_t sigs;
	sigemptyset(&sigs);
	sigaddset(&sigs, SIGUSR1);
	sigprocmask(SIG_BLOCK, &sigs, NULL);

	kill(getpid(), SIGUSR1);

	for (;;) {
		uint64_t exp = wait_for_timerfd(fd);

		printf("timer expired %u times\n", (unsigned)exp);

		total_exp += exp;
		if (total_exp >= 5) {
			break;
		}
	}

	ATF_REQUIRE(close(fd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__simple_gettime);
ATF_TC_BODY(timerfd__simple_gettime, tc)
{
	struct itimerspec curr_value;

	int fd = timerfd_create(CLOCK_MONOTONIC, 0);
	ATF_REQUIRE(fd >= 0);

	ATF_REQUIRE(timerfd_gettime(fd, &curr_value) == 0);

	ATF_REQUIRE(curr_value.it_value.tv_sec == 0);
	ATF_REQUIRE(curr_value.it_value.tv_nsec == 0);
	ATF_REQUIRE(curr_value.it_interval.tv_sec == 0);
	ATF_REQUIRE(curr_value.it_interval.tv_nsec == 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	curr_value = time;
	ATF_REQUIRE(timerfd_settime(fd, 0, &time, &curr_value) == 0);
	ATF_REQUIRE(curr_value.it_value.tv_sec == 0);
	ATF_REQUIRE(curr_value.it_value.tv_nsec == 0);
	ATF_REQUIRE(curr_value.it_interval.tv_sec == 0);
	ATF_REQUIRE(curr_value.it_interval.tv_nsec == 0);

	ATF_REQUIRE(close(fd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__simple_blocking_periodic_timer);
ATF_TC_BODY(timerfd__simple_blocking_periodic_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	uint64_t timeouts = 0;
	int num_loop_iterations = 0;

	while (timeouts < 3) {
		uint64_t timeouts_local;
		ATF_REQUIRE(
		    read(timerfd, &timeouts_local, sizeof(timeouts_local)) ==
		    (ssize_t)sizeof(timeouts_local));
		ATF_REQUIRE(timeouts_local > 0);

		++num_loop_iterations;
		timeouts += timeouts_local;
	}

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);

	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 300000000) || e.tv_sec > 0);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec >= 300000000 &&
	    e.tv_nsec < 300000000 + TIMER_SLACK);

	ATF_REQUIRE(num_loop_iterations <= 3);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__argument_checks);
ATF_TC_BODY(timerfd__argument_checks, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	ATF_REQUIRE_ERRNO(EFAULT, timerfd_settime(timerfd, 0, NULL, NULL) < 0);
	ATF_REQUIRE_ERRNO(EFAULT, timerfd_settime(-2, 0, NULL, NULL) < 0);
	ATF_REQUIRE_ERRNO(EBADF, timerfd_settime(-2, 0, &time, NULL) < 0);
	ATF_REQUIRE_ERRNO(EFAULT, timerfd_settime(-2, 42, NULL, NULL) < 0);
	ATF_REQUIRE_ERRNO(EINVAL, timerfd_settime(-2, 42, &time, NULL) < 0);
	ATF_REQUIRE_ERRNO(EINVAL,
	    timerfd_settime(timerfd, 42, &time, NULL) < 0);

	{
		time = (struct itimerspec) {
			.it_value.tv_sec = -1,
			.it_value.tv_nsec = 100000000,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 100000000,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}
	{
		time = (struct itimerspec) {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = -1,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 100000000,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}
	{
		time = (struct itimerspec) {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = 100000000,
			.it_interval.tv_sec = -1,
			.it_interval.tv_nsec = 100000000,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}
	{
		time = (struct itimerspec) {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = 100000000,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = -1,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}
	{
		time = (struct itimerspec) {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = 1000000000,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 100000000,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}
	{
		time = (struct itimerspec) {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = 100000000,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 1000000000,
		};
		ATF_REQUIRE_ERRNO(EINVAL,
		    timerfd_settime(timerfd, 0, &time, NULL) < 0);
	}

	ATF_REQUIRE_ERRNO(EINVAL,
	    timerfd_create(CLOCK_MONOTONIC | 42, TFD_CLOEXEC));
	ATF_REQUIRE_ERRNO(EINVAL,
	    timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | 42));

	ATF_REQUIRE(close(timerfd) == 0);

	struct itimerspec itimerspec;
	ATF_REQUIRE_ERRNO(EBADF, timerfd_gettime(timerfd, &itimerspec) < 0);
	ATF_REQUIRE_ERRNO(EINVAL,
	    timerfd_settime(timerfd, 0, &itimerspec, NULL) < 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__upgrade_simple_to_complex);
ATF_TC_BODY(timerfd__upgrade_simple_to_complex, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 100000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 100000000,
	};

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);
	(void)wait_for_timerfd(timerfd);

	time = (struct itimerspec) {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 50000000,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 95000000,
	};

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	uint64_t timeouts = wait_for_timerfd(timerfd);
	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE(timeouts == 1);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);
	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 50000000) || e.tv_sec > 0);
	ATF_REQUIRE_MSG(e.tv_sec == 0 && e.tv_nsec < 50000000 + TIMER_SLACK,
	    "%ld", e.tv_nsec);

	timeouts = wait_for_timerfd(timerfd);
	ATF_REQUIRE(timeouts >= 1);
	ATF_REQUIRE(timeouts == 1);

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);
	ATF_REQUIRE((e.tv_sec == 0 && e.tv_nsec >= 145000000) || e.tv_sec > 0);
	ATF_REQUIRE(e.tv_sec == 0 && e.tv_nsec >= 145000000 &&
	    e.tv_nsec < 145000000 + TIMER_SLACK);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__absolute_timer);
ATF_TC_BODY(timerfd__absolute_timer, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct timespec b, e;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	struct itimerspec time = {
		.it_value = b,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 0,
	};

	struct timespec ts_600ms = {
		.tv_sec = 0,
		.tv_nsec = 600000000,
	};

	timespecadd(&time.it_value, &ts_600ms, &time.it_value);

	ATF_REQUIRE(timerfd_settime(timerfd, /**/
			TFD_TIMER_ABSTIME, &time, NULL) == 0);

	struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
	ATF_REQUIRE(poll(&pfd, 1, -1) == 1);

	// Don't read(2) here!

	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);
	timespecsub(&e, &b, &e);
	ATF_REQUIRE(e.tv_sec == 0 &&
	    /* Don't check for this because of spurious wakeups. */
	    /* e.tv_nsec >= 600000000 && */
	    e.tv_nsec < 600000000 + TIMER_SLACK);

	struct itimerspec zeroed_its = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 0,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 0,
	};
	ATF_REQUIRE(timerfd_settime(timerfd, 0, &zeroed_its, NULL) == 0);

	uint64_t timeouts;
	ATF_REQUIRE_ERRNO(EAGAIN,
	    read(timerfd, &timeouts, sizeof(timeouts)) < 0);

	ATF_REQUIRE(poll(&pfd, 1, 0) == 0);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__absolute_timer_in_the_past);
ATF_TC_BODY(timerfd__absolute_timer_in_the_past, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct timespec b;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	{
		struct itimerspec time = {
			.it_value = b,
			.it_interval.tv_sec = 10,
			.it_interval.tv_nsec = 0,
		};
		time.it_value.tv_sec -= 1;

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, 1000) == 1);
	}

	{
		struct itimerspec time = {
			.it_value = b,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 10000000,
		};
		time.it_value.tv_sec -= 1;

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, -1) == 1);
	}

	uint64_t timeouts;
	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    (ssize_t)sizeof(timeouts));

	ATF_REQUIRE_MSG(timeouts >= 101, "%d", (int)timeouts);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__reset_absolute);
ATF_TC_BODY(timerfd__reset_absolute, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct timespec b;
	ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

	{
		struct itimerspec time = {
			.it_value = b,
		};
		time.it_value.tv_sec += 10;

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, 100) == 0);
	}

	{
		struct itimerspec time = {
			.it_value = b,
		};
		time.it_value.tv_nsec += 500000000;
		if (time.it_value.tv_nsec >= 1000000000) {
			time.it_value.tv_nsec -= 1000000000;
			time.it_value.tv_sec += 1;
		}

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, 1000) == 1);
	}

	uint64_t timeouts;
	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    (ssize_t)sizeof(timeouts));

	ATF_REQUIRE_MSG(timeouts == 1, "%d", (int)timeouts);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC(timerfd__periodic_timer_performance);
ATF_TC_HEAD(timerfd__periodic_timer_performance, tc)
{
	atf_tc_set_md_var(tc, "timeout", "1");
}
ATF_TC_BODY(timerfd__periodic_timer_performance, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	struct itimerspec time = {
		.it_value.tv_sec = 0,
		.it_value.tv_nsec = 1,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 1,
	};

	ATF_REQUIRE(timerfd_settime(timerfd, 0, &time, NULL) == 0);

	usleep(400000);

	struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
	ATF_REQUIRE(poll(&pfd, 1, -1) == 1);

	uint64_t timeouts;
	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    (ssize_t)sizeof(timeouts));
	if (timeouts < 400000000)
		atf_tc_expect_fail("https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294053");
	ATF_REQUIRE_MSG(timeouts >= 400000000, "%ld", (long)timeouts);

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__argument_overflow);
ATF_TC_BODY(timerfd__argument_overflow, tc)
{
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);
	ATF_REQUIRE(timerfd >= 0);
	{
		struct itimerspec time = {
			.it_value.tv_sec = 0,
			.it_value.tv_nsec = 1,
		};

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, -1) == 1);

		uint64_t timeouts;
		ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
		    (ssize_t)sizeof(timeouts));
		ATF_REQUIRE(timeouts == 1);

		ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) < 0);
	}
	{
		struct itimerspec time = {
			.it_value.tv_sec = LONG_MAX,
			.it_value.tv_nsec = 999999999,
		};

		ATF_REQUIRE(timerfd_settime(timerfd, /**/
				TFD_TIMER_ABSTIME, &time, NULL) == 0);

		struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
		ATF_REQUIRE(poll(&pfd, 1, 500) == 0);

		uint64_t timeouts;
		ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) < 0);
	}

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC(timerfd__short_evfilt_timer_timeout);
ATF_TC_HEAD(timerfd__short_evfilt_timer_timeout, tc)
{
	atf_tc_set_md_var(tc, "timeout", "30");
}
ATF_TC_BODY(timerfd__short_evfilt_timer_timeout, tc)
{
	int kq = kqueue();
	ATF_REQUIRE(kq >= 0);

	bool returns_early = false;

	for (int l = 0; l < 10; ++l) {
		for (int i = 1; i <= 17; ++i) {
			struct kevent kev;
			EV_SET(&kev, 0, EVFILT_TIMER, EV_ADD | EV_ONESHOT, 0, i,
			    0);

			struct timespec b;
			ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

			ATF_REQUIRE(kevent(kq, &kev, 1, NULL, 0, NULL) == 0);

			ATF_REQUIRE(kevent(kq, NULL, 0, &kev, 1, NULL) == 1);

			struct timespec e;
			ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);

			struct timespec diff;
			timespecsub(&e, &b, &diff);

			if (diff.tv_sec != 0 || diff.tv_nsec < i * 1000000) {
				fprintf(stderr,
				    "expected: %lldns, got: %lldns\n",
				    (long long)(i * 1000000LL),
				    (long long)diff.tv_nsec);
				returns_early = true;
				goto check;
			}
		}
	}

check:
	ATF_REQUIRE(!returns_early);

	ATF_REQUIRE(close(kq) == 0);

	/*
	 * timerfd's should never return early, regardless of how
	 * EVFILT_TIMER behaves.
	 */

	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);

	ATF_REQUIRE(timerfd >= 0);

	for (int l = 0; l < 10; ++l) {
		for (int i = 1; i <= 17; ++i) {
			struct itimerspec time = {
				.it_value.tv_sec = 0,
				.it_value.tv_nsec = i * 1000000,
			};

			struct timespec b;
			ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &b) == 0);

			ATF_REQUIRE(
			    timerfd_settime(timerfd, 0, &time, NULL) == 0);
			(void)wait_for_timerfd(timerfd);

			struct timespec e;
			ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &e) == 0);

			struct timespec diff;
			timespecsub(&e, &b, &diff);

			ATF_REQUIRE(
			    diff.tv_sec == 0 && diff.tv_nsec >= i * 1000000);
			fprintf(stderr, "%dms, waited %lldns\n", i,
			    (long long)diff.tv_nsec);
		}
	}

	ATF_REQUIRE(close(timerfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__unmodified_errno);
ATF_TC_BODY(timerfd__unmodified_errno, tc)
{
	ATF_REQUIRE(errno == 0);
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);
	ATF_REQUIRE(timerfd >= 0);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0,
			&(struct itimerspec) {
			    .it_value.tv_sec = 0,
			    .it_value.tv_nsec = 100000000,
			},
			NULL) == 0);
	ATF_REQUIRE(errno == 0);
	(void)wait_for_timerfd(timerfd);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0,
			&(struct itimerspec) {
			    .it_value.tv_sec = 0,
			    .it_value.tv_nsec = 0,
			},
			NULL) == 0);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0,
			&(struct itimerspec) {
			    .it_value.tv_sec = 0,
			    .it_value.tv_nsec = 0,
			},
			NULL) == 0);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(close(timerfd) == 0);
	ATF_REQUIRE(errno == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd__reset_to_very_long);
ATF_TC_BODY(timerfd__reset_to_very_long, tc)
{
	ATF_REQUIRE(errno == 0);
	int timerfd = timerfd_create(CLOCK_MONOTONIC, /**/
	    TFD_CLOEXEC | TFD_NONBLOCK);
	ATF_REQUIRE(timerfd >= 0);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0,
			&(struct itimerspec) {
			    .it_value.tv_sec = 0,
			    .it_value.tv_nsec = 100000000,
			},
			NULL) == 0);
	ATF_REQUIRE(errno == 0);

	ATF_REQUIRE(timerfd_settime(timerfd, 0,
			&(struct itimerspec) {
			    .it_value.tv_sec = 630720000,
			    .it_value.tv_nsec = 0,
			},
			NULL) == 0);
	ATF_REQUIRE(errno == 0);

	struct pollfd pfd = { .fd = timerfd, .events = POLLIN };
	ATF_REQUIRE(poll(&pfd, 1, 500) == 0);
	uint64_t timeouts;
	ssize_t r = read(timerfd, &timeouts, sizeof(timeouts));
	ATF_REQUIRE_ERRNO(EAGAIN, r < 0);

	ATF_REQUIRE(close(timerfd) == 0);
	ATF_REQUIRE(errno == EAGAIN);
}

ATF_TC_WITHOUT_HEAD(timerfd__missed_events);
ATF_TC_BODY(timerfd__missed_events, tc)
{
	struct itimerspec its = { };
	uint64_t timeouts;
	int timerfd;

	timerfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(timerfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &its.it_value) == 0);
	its.it_value.tv_sec -= 1000;
	its.it_interval.tv_sec = 1;

	ATF_REQUIRE(timerfd_settime(timerfd, TFD_TIMER_ABSTIME, &its,
	    NULL) == 0);

	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    sizeof(timeouts));
	ATF_REQUIRE_MSG(timeouts == 1001, "%ld", (long)timeouts);

	ATF_REQUIRE(read(timerfd, &timeouts, sizeof(timeouts)) ==
	    sizeof(timeouts));
	ATF_REQUIRE_MSG(timeouts == 1, "%ld", (long)timeouts);

	ATF_REQUIRE(close(timerfd) == 0);
}

/*
 * Tests requiring root (clock_settime on CLOCK_REALTIME).
 * Tests gracefully skip if not running as root.
 */

static struct timespec current_time;
static void
reset_time(void)
{
	(void)clock_settime(CLOCK_REALTIME, &current_time);
}

static void
clock_settime_or_skip_test(clockid_t clockid, struct timespec const *ts)
{
	int r = clock_settime(clockid, ts);
	if (r < 0 && errno == EPERM) {
		atf_tc_skip("root required");
	}
	ATF_REQUIRE(r == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd_root__zero_read_on_abs_realtime);
ATF_TC_BODY(timerfd_root__zero_read_on_abs_realtime, tc)
{
	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	ATF_REQUIRE(timerfd_settime(tfd, TFD_TIMER_ABSTIME,
			&(struct itimerspec) {
			    .it_value = current_time,
			    .it_interval.tv_sec = 1,
			    .it_interval.tv_nsec = 0,
			},
			NULL) == 0);

	ATF_REQUIRE(
	    poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1, -1) == 1);

	clock_settime_or_skip_test(CLOCK_REALTIME,
	    &(struct timespec) {
		.tv_sec = current_time.tv_sec - 1,
		.tv_nsec = current_time.tv_nsec,
	    });

	uint64_t exp;
	ssize_t r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_MSG(r == 0, "r: %d, errno: %d", (int)r, errno);

	{
		int r = fcntl(tfd, F_GETFL);
		ATF_REQUIRE(r >= 0);
		r = fcntl(tfd, F_SETFL, r | O_NONBLOCK);
		ATF_REQUIRE(r >= 0);
	}

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_ERRNO(EAGAIN, r < 0);

	current_time.tv_sec += 1;
	ATF_REQUIRE(poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1,
			1800) == 1);
	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE(r == (ssize_t)sizeof(exp));
	ATF_REQUIRE(exp == 1);

	ATF_REQUIRE(close(tfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd_root__read_on_abs_realtime_no_interval);
ATF_TC_BODY(timerfd_root__read_on_abs_realtime_no_interval, tc)
{
	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	ATF_REQUIRE(timerfd_settime(tfd, TFD_TIMER_ABSTIME,
			&(struct itimerspec) {
			    .it_value = current_time,
			    .it_interval.tv_sec = 0,
			    .it_interval.tv_nsec = 0,
			},
			NULL) == 0);

	ATF_REQUIRE(
	    poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1, -1) == 1);

	clock_settime_or_skip_test(CLOCK_REALTIME,
	    &(struct timespec) {
		.tv_sec = current_time.tv_sec - 1,
		.tv_nsec = current_time.tv_nsec,
	    });

	uint64_t exp;
	ssize_t r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE(r == (ssize_t)sizeof(exp));
	ATF_REQUIRE(exp == 1);

	ATF_REQUIRE(close(tfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd_root__cancel_on_set);
ATF_TC_BODY(timerfd_root__cancel_on_set, tc)
{
	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	ATF_REQUIRE(
	    timerfd_settime(tfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		&(struct itimerspec) {
		    .it_value.tv_sec = current_time.tv_sec + 10,
		    .it_value.tv_nsec = current_time.tv_nsec,
		    .it_interval.tv_sec = 0,
		    .it_interval.tv_nsec = 0,
		},
		NULL) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	ATF_REQUIRE(
	    poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1, -1) == 1);

	{
		int r = timerfd_settime(tfd,
		    TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		    &(struct itimerspec) {
			.it_value.tv_sec = current_time.tv_sec,
			.it_value.tv_nsec = current_time.tv_nsec,
			.it_interval.tv_sec = 0,
			.it_interval.tv_nsec = 0,
		    },
		    NULL);
		ATF_REQUIRE_ERRNO(ECANCELED, r < 0);
	}

	ATF_REQUIRE(poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1,
			800) == 1);

	uint64_t exp;
	ssize_t r;

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE(r == (ssize_t)sizeof(exp));
	ATF_REQUIRE(exp == 1);

	ATF_REQUIRE(
	    timerfd_settime(tfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		&(struct itimerspec) {
		    .it_value.tv_sec = current_time.tv_sec + 1,
		    .it_value.tv_nsec = current_time.tv_nsec,
		    .it_interval.tv_sec = 1,
		    .it_interval.tv_nsec = 0,
		},
		NULL) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	ATF_REQUIRE(
	    poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1, -1) == 1);

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_ERRNO(ECANCELED, r < 0);

	r = read(tfd, &exp, sizeof(exp));
	current_time.tv_sec += 1;
	ATF_REQUIRE_MSG(r == (ssize_t)sizeof(exp), "%d %d", (int)r, errno);
	ATF_REQUIRE(exp == 1);

	ATF_REQUIRE(
	    timerfd_settime(tfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		&(struct itimerspec) {
		    .it_value.tv_sec = current_time.tv_sec + 1,
		    .it_value.tv_nsec = current_time.tv_nsec,
		    .it_interval.tv_sec = 1,
		    .it_interval.tv_nsec = 0,
		},
		NULL) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);
	current_time.tv_sec += 2;
	ATF_REQUIRE(nanosleep(&(struct timespec) { .tv_sec = 2 }, NULL) == 0);

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_ERRNO(ECANCELED, r < 0);

	r = poll(&(struct pollfd) { .fd = tfd, .events = POLLIN }, 1, 3000);
	ATF_REQUIRE(r == 0);
	current_time.tv_sec += 3;

	ATF_REQUIRE(close(tfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd_root__cancel_on_set_init);
ATF_TC_BODY(timerfd_root__cancel_on_set_init, tc)
{
	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	ATF_REQUIRE(
	    timerfd_settime(tfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		&(struct itimerspec) {
		    .it_value.tv_sec = current_time.tv_sec + 10,
		    .it_value.tv_nsec = current_time.tv_nsec,
		    .it_interval.tv_sec = 0,
		    .it_interval.tv_nsec = 0,
		},
		NULL) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	int r = timerfd_settime(tfd,
	    TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
	    &(struct itimerspec) {
		.it_value.tv_sec = current_time.tv_sec + 10,
		.it_value.tv_nsec = current_time.tv_nsec,
		.it_interval.tv_sec = 0,
		.it_interval.tv_nsec = 0,
	    },
	    NULL);
	ATF_REQUIRE_ERRNO(ECANCELED, r < 0);
	ATF_REQUIRE(close(tfd) == 0);
}

static void *
clock_change_thread(void *arg)
{
	(void)arg;

	fprintf(stderr, "clock change\n");
	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	current_time.tv_sec += 2;
	ATF_REQUIRE(nanosleep(&(struct timespec) { .tv_sec = 2 }, NULL) == 0);

	fprintf(stderr, "clock change\n");
	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

	return NULL;
}

ATF_TC(timerfd_root__clock_change_notification);
ATF_TC_HEAD(timerfd_root__clock_change_notification, tc)
{
	atf_tc_set_md_var(tc, "timeout", "10");
}
ATF_TC_BODY(timerfd_root__clock_change_notification, tc)
{
	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);

#define TIME_T_MAX (time_t)((UINTMAX_C(1) << ((sizeof(time_t) << 3) - 1)) - 1)
	struct itimerspec its = {
		.it_value.tv_sec = TIME_T_MAX,
	};
#undef TIME_T_MAX

	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(
	    timerfd_settime(tfd, TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
		&its, NULL) == 0);

	pthread_t clock_changer;
	ATF_REQUIRE(pthread_create(&clock_changer, NULL, /**/
			clock_change_thread, NULL) == 0);

	uint64_t exp;
	ssize_t r;

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_ERRNO(ECANCELED, r < 0);
	fprintf(stderr, "clock change detected\n");

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE_ERRNO(ECANCELED, r < 0);
	fprintf(stderr, "clock change detected\n");

	ATF_REQUIRE(pthread_join(clock_changer, NULL) == 0);

	ATF_REQUIRE(close(tfd) == 0);
}

ATF_TC_WITHOUT_HEAD(timerfd_root__advance_time_no_cancel);
ATF_TC_BODY(timerfd_root__advance_time_no_cancel, tc)
{
	int tfd = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
	ATF_REQUIRE(tfd >= 0);

	ATF_REQUIRE(clock_gettime(CLOCK_REALTIME, &current_time) == 0);
	ATF_REQUIRE(atexit(reset_time) == 0);

	ATF_REQUIRE(timerfd_settime(tfd, TFD_TIMER_ABSTIME,
			&(struct itimerspec) {
			    .it_value.tv_sec = current_time.tv_sec + 10,
			    .it_value.tv_nsec = current_time.tv_nsec,
			    .it_interval.tv_sec = 0,
			    .it_interval.tv_nsec = 0,
			},
			NULL) == 0);

	current_time.tv_sec += 9;
	clock_settime_or_skip_test(CLOCK_REALTIME, &current_time);
	current_time.tv_sec -= 8;

	{
		int r = poll(&(struct pollfd) { .fd = tfd, .events = POLLIN },
		    1, 1800);
		ATF_REQUIRE(r == 1);
	}

	uint64_t exp;
	ssize_t r;

	r = read(tfd, &exp, sizeof(exp));
	ATF_REQUIRE(r == (ssize_t)sizeof(exp));
	ATF_REQUIRE(exp == 1);

	ATF_REQUIRE(close(tfd) == 0);
}

ATF_TP_ADD_TCS(tp)
{
	ATF_TP_ADD_TC(tp, timerfd__many_timers);
	ATF_TP_ADD_TC(tp, timerfd__simple_timer);
	ATF_TP_ADD_TC(tp, timerfd__simple_periodic_timer);
	ATF_TP_ADD_TC(tp, timerfd__complex_periodic_timer);
	ATF_TP_ADD_TC(tp, timerfd__reset_periodic_timer);
	ATF_TP_ADD_TC(tp, timerfd__reenable_periodic_timer);
	ATF_TP_ADD_TC(tp, timerfd__expire_five);
	ATF_TP_ADD_TC(tp, timerfd__simple_gettime);
	ATF_TP_ADD_TC(tp, timerfd__simple_blocking_periodic_timer);
	ATF_TP_ADD_TC(tp, timerfd__argument_checks);
	ATF_TP_ADD_TC(tp, timerfd__upgrade_simple_to_complex);
	ATF_TP_ADD_TC(tp, timerfd__absolute_timer);
	ATF_TP_ADD_TC(tp, timerfd__absolute_timer_in_the_past);
	ATF_TP_ADD_TC(tp, timerfd__reset_absolute);
	ATF_TP_ADD_TC(tp, timerfd__periodic_timer_performance);
	ATF_TP_ADD_TC(tp, timerfd__argument_overflow);
	ATF_TP_ADD_TC(tp, timerfd__short_evfilt_timer_timeout);
	ATF_TP_ADD_TC(tp, timerfd__unmodified_errno);
	ATF_TP_ADD_TC(tp, timerfd__reset_to_very_long);
	ATF_TP_ADD_TC(tp, timerfd__missed_events);

	ATF_TP_ADD_TC(tp, timerfd_root__zero_read_on_abs_realtime);
	ATF_TP_ADD_TC(tp, timerfd_root__read_on_abs_realtime_no_interval);
	ATF_TP_ADD_TC(tp, timerfd_root__cancel_on_set);
	ATF_TP_ADD_TC(tp, timerfd_root__cancel_on_set_init);
	ATF_TP_ADD_TC(tp, timerfd_root__clock_change_notification);
	ATF_TP_ADD_TC(tp, timerfd_root__advance_time_no_cancel);

	return atf_no_error();
}