1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * 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 = "from: @(#)sleep.c 5.6 (Berkeley) 2/23/91";*/ 36 static char *rcsid = "$Id: sleep.c,v 1.5 1994/12/11 17:34:10 mycroft Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <sys/time.h> 40 #include <signal.h> 41 #include <unistd.h> 42 43 unsigned int 44 sleep(seconds) 45 unsigned int seconds; 46 { 47 struct itimerval itv, oitv; 48 struct sigaction act, oact; 49 struct timeval diff; 50 sigset_t set, oset; 51 static void sleephandler(); 52 53 if (!seconds) 54 return 0; 55 56 sigemptyset(&set); 57 sigaddset(&set, SIGALRM); 58 sigprocmask(SIG_BLOCK, &set, &oset); 59 60 act.sa_handler = sleephandler; 61 act.sa_flags = 0; 62 sigemptyset(&act.sa_mask); 63 sigaction(SIGALRM, &act, &oact); 64 65 timerclear(&itv.it_interval); 66 itv.it_value.tv_sec = seconds; 67 itv.it_value.tv_usec = 0; 68 timerclear(&diff); 69 setitimer(ITIMER_REAL, &itv, &oitv); 70 71 if (timerisset(&oitv.it_value)) { 72 if (timercmp(&oitv.it_value, &itv.it_value, >)) { 73 oitv.it_value.tv_sec -= itv.it_value.tv_sec; 74 } else { 75 /* 76 * The existing timer was scheduled to fire 77 * before ours, so we compute the time diff 78 * so we can add it back in the end. 79 */ 80 diff = itv.it_value; 81 __timersub(&diff, &oitv.it_value); 82 itv.it_value = oitv.it_value; 83 /* 84 * This is a hack, but we must have time to return 85 * from the setitimer after the alarm or else it'll 86 * be restarted. And, anyway, sleep never did 87 * anything more than this before. 88 */ 89 oitv.it_value.tv_sec = 1; 90 oitv.it_value.tv_usec = 0; 91 92 setitimer(ITIMER_REAL, &itv, NULL); 93 } 94 } 95 96 (void) sigsuspend (&oset); 97 98 sigaction(SIGALRM, &oact, NULL); 99 sigprocmask(SIG_SETMASK, &oset, NULL); 100 101 (void) setitimer(ITIMER_REAL, &oitv, &itv); 102 103 if (timerisset(&diff)) 104 __timeradd(&itv.it_value, &diff); 105 106 return (itv.it_value.tv_sec); 107 } 108 109 static void 110 sleephandler() 111 { 112 } 113