1/* $OpenBSD: ualarm.c,v 1.7 2005/08/08 08:05:34 espie Exp $ */ 2/* 3 * Copyright (c) 1985, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31#include <sys/types.h> 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 */ 42useconds_t 43ualarm(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 ((useconds_t)(old.it_value.tv_sec * USPS + old.it_value.tv_usec)); 55 /* else */ 56 return ((useconds_t)-1); 57} 58