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/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$OpenBSD: usleep.c,v 1.4 1996/09/15 09:31:11 tholo Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/time.h>
#include <signal.h>
#include <unistd.h>
#define TICK 10000 /* system clock resolution in microseconds */
static void sleephandler __P((int));
static volatile int ringring;
void
usleep(useconds)
unsigned int useconds;
{
struct itimerval itv, oitv;
struct sigaction act, oact;
sigset_t set, oset;
if (!useconds)
return;
sigemptyset(&set);
sigaddset(&set, SIGALRM);
sigprocmask(SIG_BLOCK, &set, &oset);
act.sa_handler = sleephandler;
act.sa_flags = 0;
sigemptyset(&act.sa_mask);
sigaction(SIGALRM, &act, &oact);
timerclear(&itv.it_interval);
itv.it_value.tv_sec = useconds / 1000000;
itv.it_value.tv_usec = useconds % 1000000;
setitimer(ITIMER_REAL, &itv, &oitv);
if (timerisset(&oitv.it_value)) {
if (timercmp(&oitv.it_value, &itv.it_value, >)) {
timersub(&oitv.it_value, &itv.it_value, &oitv.it_value);
} else {
itv.it_value = oitv.it_value;
/*
* This is a hack, but we must have time to return
* from the setitimer after the alarm or else it'll
* be restarted. And, anyway, sleep never did
* anything more than this before.
*/
oitv.it_value.tv_sec = 0;
oitv.it_value.tv_usec = 2 * TICK;
setitimer(ITIMER_REAL, &itv, NULL);
}
}
set = oset;
sigdelset(&set, SIGALRM);
ringring = 0;
(void) sigsuspend(&set);
if (!ringring) {
struct itimerval nulltv;
/*
* Interrupted by other signal; allow for pending
* SIGALRM to be processed before resetting handler,
* after first turning off the timer.
*/
timerclear(&nulltv.it_interval);
timerclear(&nulltv.it_value);
(void) setitimer(ITIMER_REAL, &nulltv, NULL);
}
sigprocmask(SIG_SETMASK, &oset, NULL);
sigaction(SIGALRM, &oact, NULL);
(void) setitimer(ITIMER_REAL, &oitv, NULL);
}
/* ARGSUSED */
static void
sleephandler(sig)
int sig;
{
ringring = 1;
}
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