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 1.4 1994/05/28 06:25:04 jtc 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 register struct itimerval *itp; 48 struct itimerval itv, oitv; 49 struct sigaction act, oact; 50 struct timeval diff; 51 sigset_t set, oset; 52 static void sleephandler(); 53 54 itp = &itv; 55 if (!seconds) 56 return 0; 57 58 sigemptyset (&set); 59 sigaddset (&set, SIGALRM); 60 sigprocmask(SIG_BLOCK, &set, &oset); 61 62 act.sa_handler = sleephandler; 63 act.sa_flags = 0; 64 sigemptyset(&act.sa_mask); 65 sigaction(SIGALRM, &act, &oact); 66 67 timerclear(&itp->it_interval); 68 itp->it_value.tv_sec = seconds; 69 itp->it_value.tv_usec = 0; 70 diff.tv_sec = diff.tv_usec = 0; 71 setitimer(ITIMER_REAL, itp, &oitv); 72 73 if (timerisset(&oitv.it_value)) { 74 if (timercmp(&oitv.it_value, &itp->it_value, >)) { 75 oitv.it_value.tv_sec -= itv.it_value.tv_sec; 76 } else { 77 /* The existing timer was scheduled to fire 78 before ours, so we compute the time diff 79 so we can add it back in the end. */ 80 81 itp->it_value.tv_sec -= oitv.it_value.tv_sec; 82 itp->it_value.tv_usec -= oitv.it_value.tv_usec; 83 if (itp->it_value.tv_usec < 0) { 84 itp->it_value.tv_sec--; 85 itp->it_value.tv_usec += 1000000; 86 } 87 diff = itp->it_value; 88 89 itp->it_value = oitv.it_value; 90 /* 91 * This is a hack, but we must have time to return 92 * from the setitimer after the alarm or else it'll 93 * be restarted. And, anyway, sleep never did 94 * anything more than this before. 95 */ 96 oitv.it_value.tv_sec = 1; 97 oitv.it_value.tv_usec = 0; 98 99 setitimer(ITIMER_REAL, &itv, NULL); 100 } 101 } 102 103 (void) sigsuspend (&oset); 104 105 sigaction(SIGALRM, &oact, NULL); 106 sigprocmask(SIG_SETMASK, &oset, NULL); 107 108 (void) setitimer(ITIMER_REAL, &oitv, itp); 109 110 if (diff.tv_sec != 0 || diff.tv_usec != 0) { 111 itp->it_value.tv_sec += diff.tv_sec; 112 itp->it_value.tv_usec += diff.tv_usec; 113 if (itp->it_value.tv_usec > 1000000) { 114 itp->it_value.tv_usec -= 1000000; 115 itp->it_value.tv_sec++; 116 } 117 } 118 119 return (itp->it_value.tv_sec); 120 } 121 122 static void 123 sleephandler() 124 { 125 } 126