usleep.c revision 28111
1/* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#if defined(LIBC_SCCS) && !defined(lint) 35static char sccsid[] = "@(#)usleep.c 8.1 (Berkeley) 6/4/93"; 36#endif /* LIBC_SCCS and not lint */ 37 38#include <sys/time.h> 39#include <signal.h> 40#include <unistd.h> 41#ifdef _THREAD_SAFE 42#include <pthread.h> 43#include "pthread_private.h" 44#endif 45 46#ifndef _THREAD_SAFE 47static int alarm_termination; 48 49static void 50sleephandler() 51{ 52 alarm_termination++; 53} 54#endif /* _THREAD_SAFE */ 55 56 57void 58usleep(useconds) 59 unsigned int useconds; 60{ 61#ifdef _THREAD_SAFE 62 struct timespec time_to_sleep; 63 struct timespec time_remaining; 64 65 if (useconds) { 66 time_to_sleep.tv_nsec = (useconds % 1000000) * 1000; 67 time_to_sleep.tv_sec = useconds / 1000000; 68 do { 69 nanosleep(&time_to_sleep, &time_remaining); 70 time_to_sleep = time_remaining; 71 } while (time_to_sleep.tv_sec != 0 || 72 time_to_sleep.tv_nsec != 0); 73 } 74#else 75 struct timespec time_to_sleep; 76 struct timespec time_remaining; 77 struct sigaction act, oact; 78 sigset_t mask, omask; 79 80 if (useconds != 0) { 81 time_to_sleep.tv_nsec = (useconds % 1000000) * 1000; 82 time_to_sleep.tv_sec = useconds / 1000000; 83 84 /* 85 * Set up handler to interrupt signanosleep and ensure 86 * SIGARLM is not blocked. Block SIGALRM while fiddling 87 * with things. 88 */ 89 memset(&act, 0, sizeof(act)); 90 act.sa_handler = sleephandler; 91 sigemptyset(&mask); 92 sigaddset(&mask, SIGALRM); 93 sigprocmask(SIG_BLOCK, &mask, &omask); 94 sigaction(SIGALRM, &act, &oact); 95 mask = omask; 96 sigdelset(&mask, SIGALRM); 97 alarm_termination = 0; 98 99 /* 100 * signanosleep() uses the given mask for the lifetime of 101 * the syscall only - it resets on return. Note that the 102 * old sleep explicitly unblocks SIGALRM during the sleep. 103 */ 104 105 do { 106 signanosleep(&time_to_sleep, &time_remaining, &mask); 107 time_to_sleep = time_remaining; 108 } while (!alarm_termination && 109 (time_to_sleep.tv_sec != 0 || 110 time_to_sleep.tv_nsec != 0)); 111 112 /* Unwind */ 113 sigaction(SIGALRM, &oact, (struct sigaction *)0); 114 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0); 115 } 116#endif /* _THREAD_SAFE */ 117} 118