1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1985, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__SCCSID("@(#)ualarm.c	8.1 (Berkeley) 6/4/93");
34__FBSDID("$FreeBSD$");
35
36#include <sys/time.h>
37#include <unistd.h>
38
39#define	USPS	1000000		/* # of microseconds in a second */
40
41/*
42 * Generate a SIGALRM signal in ``usecs'' microseconds.
43 * If ``reload'' is non-zero, keep generating SIGALRM
44 * every ``reload'' microseconds after the first signal.
45 */
46useconds_t
47ualarm(useconds_t usecs, useconds_t reload)
48{
49	struct itimerval new, old;
50
51	new.it_interval.tv_usec = reload % USPS;
52	new.it_interval.tv_sec = reload / USPS;
53
54	new.it_value.tv_usec = usecs % USPS;
55	new.it_value.tv_sec = usecs / USPS;
56
57	if (setitimer(ITIMER_REAL, &new, &old) == 0)
58		return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
59	return (-1);
60}
61