8d7bf613b2
and return to previous Peter's variant. POSIX says that this place is implementation defined and old variant allows application block SIGALRM and sleep and not be killed by external SIGALRMs. BTW, GNU sleep f.e. sleeps forever in blocked SIGALRM :-)
128 lines
4.1 KiB
C
128 lines
4.1 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 <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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nanosleep(&time_to_sleep, &time_remaining);
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time_to_sleep = time_remaining;
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} while (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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sigprocmask(SIG_BLOCK, &mask, &omask);
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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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sigaction(SIGALRM, &act, &oact);
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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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signanosleep(&time_to_sleep, &time_remaining, &omask);
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time_to_sleep = time_remaining;
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} while (!alarm_termination &&
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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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sigaction(SIGALRM, &oact, (struct sigaction *)0);
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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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