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) 35 static 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 47 static void 48 sleephandler() 49 { 50 return; 51 } 52 #endif /* _THREAD_SAFE */ 53 54 55 void 56 usleep(useconds) 57 unsigned int useconds; 58 { 59 #ifdef _THREAD_SAFE 60 struct timespec time_to_sleep; 61 struct timespec time_remaining; 62 63 if (useconds) { 64 time_to_sleep.tv_nsec = (useconds % 1000000) * 1000; 65 time_to_sleep.tv_sec = useconds / 1000000; 66 do { 67 nanosleep(&time_to_sleep, &time_remaining); 68 time_to_sleep = time_remaining; 69 } while (time_to_sleep.tv_sec != 0 && 70 time_to_sleep.tv_nsec != 0); 71 } 72 #else 73 struct timespec time_to_sleep; 74 struct timespec time_remaining; 75 struct sigaction act, oact; 76 sigset_t mask, omask; 77 int alarm_blocked; 78 79 if (useconds != 0) { 80 time_to_sleep.tv_nsec = (useconds % 1000000) * 1000; 81 time_to_sleep.tv_sec = useconds / 1000000; 82 83 /* Block SIGALRM while fiddling with it */ 84 sigemptyset(&mask); 85 sigaddset(&mask, SIGALRM); 86 sigprocmask(SIG_BLOCK, &mask, &omask); 87 88 /* Was SIGALRM blocked already? */ 89 alarm_blocked = sigismember(&omask, SIGALRM); 90 91 if (!alarm_blocked) { 92 /* 93 * Set up handler to interrupt signanosleep only if 94 * SIGALRM was unblocked. (Save some syscalls) 95 */ 96 memset(&act, 0, sizeof(act)); 97 act.sa_handler = sleephandler; 98 sigaction(SIGALRM, &act, &oact); 99 } 100 101 /* 102 * signanosleep() uses the given mask for the lifetime of 103 * the syscall only - it resets on return. Note that the 104 * Old sleep explicitly unblocks SIGALRM during the sleep, 105 * we don't do that now since we don't depend on SIGALRM 106 * to end the timout. If the process blocks SIGALRM, it 107 * gets what it asks for. 108 */ 109 110 do { 111 signanosleep(&time_to_sleep, &time_remaining, &mask); 112 time_to_sleep = time_remaining; 113 } while (time_to_sleep.tv_sec != 0 && 114 time_to_sleep.tv_nsec != 0); 115 116 if (!alarm_blocked) { 117 /* Unwind */ 118 sigaction(SIGALRM, &oact, (struct sigaction *)0); 119 sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0); 120 } 121 } 122 #endif /* _THREAD_SAFE */ 123 } 124