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/time.h>
33 #include <unistd.h>
34
35 #define USPS 1000000 /* # of microseconds in a second */
36
37 /*
38 * Generate a SIGALRM signal in ``usecs'' microseconds.
39 * If ``reload'' is non-zero, keep generating SIGALRM
40 * every ``reload'' microseconds after the first signal.
41 */
42 useconds_t
ualarm(useconds_t usecs,useconds_t reload)43 ualarm(useconds_t usecs, useconds_t reload)
44 {
45 struct itimerval new, old;
46
47 new.it_interval.tv_usec = reload % USPS;
48 new.it_interval.tv_sec = reload / USPS;
49
50 new.it_value.tv_usec = usecs % USPS;
51 new.it_value.tv_sec = usecs / USPS;
52
53 if (setitimer(ITIMER_REAL, &new, &old) == 0)
54 return (old.it_value.tv_sec * USPS + old.it_value.tv_usec);
55 return (-1);
56 }
57