1 /* $NetBSD: ualarm.c,v 1.11 2012/06/25 22:32:44 abs Exp $ */
2
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 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)ualarm.c 8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: ualarm.c,v 1.11 2012/06/25 22:32:44 abs Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40
41 #include "namespace.h"
42 #include <sys/time.h>
43 #include <unistd.h>
44
45 #ifdef __weak_alias
__weak_alias(ualarm,_ualarm)46 __weak_alias(ualarm,_ualarm)
47 #endif
48
49 #define USPS 1000000 /* # of microseconds in a second */
50
51 /*
52 * Generate a SIGALRM signal in ``usecs'' microseconds.
53 * If ``reload'' is non-zero, keep generating SIGALRM
54 * every ``reload'' microseconds after the first signal.
55 */
56 useconds_t
57 ualarm(useconds_t usecs, useconds_t reload)
58 {
59 struct itimerval new, old;
60
61 new.it_interval.tv_usec = reload % USPS;
62 new.it_interval.tv_sec = reload / USPS;
63
64 new.it_value.tv_usec = usecs % USPS;
65 new.it_value.tv_sec = usecs / USPS;
66
67 if (setitimer(ITIMER_REAL, &new, &old) == 0)
68 return (useconds_t)(old.it_value.tv_sec * USPS +
69 old.it_value.tv_usec);
70
71 return (useconds_t)-1;
72 }
73