genode/repos/libports/src/lib/libc/gettimeofday.cc

/*
 * \brief  C-library back end
 * \author Norman Feske
 * \date   2008-11-11
 */

/*
 * Copyright (C) 2008-2017 Genode Labs GmbH
 *
 * This file is part of the Genode OS framework, which is distributed
 * under the terms of the GNU Affero General Public License version 3.
 */

/* Libc includes */
#include <sys/time.h>

#include "task.h"


namespace Libc { time_t read_rtc(); }


extern "C" __attribute__((weak))
int gettimeofday(struct timeval *tv, struct timezone *)
{
	if (!tv) return 0;

	static bool read_rtc = false;
	static time_t rtc = 0;
	static unsigned long t0 = 0;

	if (!read_rtc) {
		rtc = Libc::read_rtc();
		read_rtc = true;
		t0 = Libc::current_time();
	}

	unsigned long time = Libc::current_time() - t0;

	tv->tv_sec  = rtc + time/1000;
	tv->tv_usec = (time % 1000) * 1000;

	return 0;
}