124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
/* $NetBSD: usleep.c,v 1.11 1997/07/13 19:41:46 christos Exp $ */
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/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)usleep.c 8.1 (Berkeley) 6/4/93";
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#else
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__RCSID("$NetBSD: usleep.c,v 1.11 1997/07/13 19:41:46 christos Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include <sys/time.h>
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#include <signal.h>
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#include <unistd.h>
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#define TICK 10000 /* system clock resolution in microseconds */
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static volatile int ringring;
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static void sleephandler __P((int));
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void
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usleep(useconds)
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unsigned int useconds;
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{
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struct itimerval itv, oitv;
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struct sigaction act, oact;
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sigset_t set, oset;
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if (!useconds)
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return;
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sigemptyset(&set);
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sigaddset(&set, SIGALRM);
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sigprocmask(SIG_BLOCK, &set, &oset);
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act.sa_handler = sleephandler;
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act.sa_flags = 0;
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sigemptyset(&act.sa_mask);
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sigaction(SIGALRM, &act, &oact);
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timerclear(&itv.it_interval);
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itv.it_value.tv_sec = useconds / 1000000;
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itv.it_value.tv_usec = useconds % 1000000;
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setitimer(ITIMER_REAL, &itv, &oitv);
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if (timerisset(&oitv.it_value)) {
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if (timercmp(&oitv.it_value, &itv.it_value, >)) {
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timersub(&oitv.it_value, &itv.it_value, &oitv.it_value);
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} else {
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itv.it_value = oitv.it_value;
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/*
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* This is a hack, but we must have time to return
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* from the setitimer after the alarm or else it'll
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* be restarted. And, anyway, sleep never did
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* anything more than this before.
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*/
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oitv.it_value.tv_sec = 0;
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oitv.it_value.tv_usec = 2 * TICK;
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setitimer(ITIMER_REAL, &itv, NULL);
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}
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}
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set = oset;
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sigdelset(&set, SIGALRM);
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ringring = 0;
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(void) sigsuspend(&set);
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if (!ringring) {
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struct itimerval nulltv;
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/*
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* Interrupted by other signal; allow for pending
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* SIGALRM to be processed before resetting handler,
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* after first turning off the timer.
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*/
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timerclear(&nulltv.it_interval);
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timerclear(&nulltv.it_value);
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(void) setitimer(ITIMER_REAL, &nulltv, NULL);
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}
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sigprocmask(SIG_SETMASK, &oset, NULL);
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sigaction(SIGALRM, &oact, NULL);
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(void) setitimer(ITIMER_REAL, &oitv, NULL);
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}
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static void
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sleephandler(n)
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int n;
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{
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ringring = 1;
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}
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