137 lines
4.3 KiB
C
137 lines
4.3 KiB
C
/*
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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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)usleep.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <errno.h>
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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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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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#endif
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#ifndef _THREAD_SAFE
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static int alarm_termination;
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static void
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sleephandler()
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{
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alarm_termination++;
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}
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#endif /* _THREAD_SAFE */
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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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#ifdef _THREAD_SAFE
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struct timespec time_to_sleep;
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struct timespec time_remaining;
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if (useconds) {
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time_to_sleep.tv_nsec = (useconds % 1000000) * 1000;
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time_to_sleep.tv_sec = useconds / 1000000;
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do {
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(void)nanosleep(&time_to_sleep, &time_remaining);
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time_to_sleep = time_remaining;
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} while (!errno || errno == EINTR ||
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time_to_sleep.tv_sec != 0 ||
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time_to_sleep.tv_nsec != 0);
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}
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#else
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struct timespec time_to_sleep;
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struct timespec time_remaining;
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struct sigaction act, oact;
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sigset_t mask, omask;
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int alarm_blocked;
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if (useconds != 0) {
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time_to_sleep.tv_nsec = (useconds % 1000000) * 1000;
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time_to_sleep.tv_sec = useconds / 1000000;
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/* Block SIGALRM while fiddling with it */
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sigemptyset(&mask);
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sigaddset(&mask, SIGALRM);
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if (sigprocmask(SIG_BLOCK, &mask, &omask))
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return;
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alarm_termination = 0;
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/* Was SIGALRM blocked already? */
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alarm_blocked = sigismember(&omask, SIGALRM);
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if (!alarm_blocked) {
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/*
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* Set up handler to interrupt signanosleep only if
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* SIGALRM was unblocked. (Save some syscalls)
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*/
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memset(&act, 0, sizeof(act));
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act.sa_handler = sleephandler;
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if (sigaction(SIGALRM, &act, &oact)) {
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(void)sigprocmask(SIG_SETMASK, &omask,
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(sigset_t *)0);
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return;
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}
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}
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/*
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* signanosleep() uses the given mask for the lifetime of
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* the syscall only - it resets on return. Note that the
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* old sleep() explicitly unblocks SIGALRM during the sleep,
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* we don't do that now since we don't depend on SIGALRM
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* to end the timeout. If the process blocks SIGALRM, it
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* gets what it asks for.
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*/
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do {
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(void)signanosleep(&time_to_sleep, &time_remaining,
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&omask);
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time_to_sleep = time_remaining;
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} while (!alarm_termination &&
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(!errno || errno == EINTR ||
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time_to_sleep.tv_sec != 0 ||
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time_to_sleep.tv_nsec != 0));
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if (!alarm_blocked) {
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/* Unwind */
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(void)sigaction(SIGALRM, &oact, (struct sigaction *)0);
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(void)sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
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}
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}
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#endif /* _THREAD_SAFE */
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}
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