1 /* $NetBSD: sleep.c,v 1.6 1995/02/27 05:51:55 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)sleep.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 static char rcsid[] = "$NetBSD"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <sys/time.h> 45 #include <signal.h> 46 #include <unistd.h> 47 48 unsigned int 49 sleep(seconds) 50 unsigned int seconds; 51 { 52 struct itimerval itv, oitv; 53 struct sigaction act, oact; 54 struct timeval diff; 55 sigset_t set, oset; 56 static void sleephandler(); 57 58 if (!seconds) 59 return 0; 60 61 sigemptyset(&set); 62 sigaddset(&set, SIGALRM); 63 sigprocmask(SIG_BLOCK, &set, &oset); 64 65 act.sa_handler = sleephandler; 66 act.sa_flags = 0; 67 sigemptyset(&act.sa_mask); 68 sigaction(SIGALRM, &act, &oact); 69 70 timerclear(&itv.it_interval); 71 itv.it_value.tv_sec = seconds; 72 itv.it_value.tv_usec = 0; 73 timerclear(&diff); 74 setitimer(ITIMER_REAL, &itv, &oitv); 75 76 if (timerisset(&oitv.it_value)) { 77 if (timercmp(&oitv.it_value, &itv.it_value, >)) { 78 oitv.it_value.tv_sec -= itv.it_value.tv_sec; 79 } else { 80 /* 81 * The existing timer was scheduled to fire 82 * before ours, so we compute the time diff 83 * so we can add it back in the end. 84 */ 85 diff = itv.it_value; 86 __timersub(&diff, &oitv.it_value); 87 itv.it_value = oitv.it_value; 88 /* 89 * This is a hack, but we must have time to return 90 * from the setitimer after the alarm or else it'll 91 * be restarted. And, anyway, sleep never did 92 * anything more than this before. 93 */ 94 oitv.it_value.tv_sec = 1; 95 oitv.it_value.tv_usec = 0; 96 97 setitimer(ITIMER_REAL, &itv, NULL); 98 } 99 } 100 101 (void) sigsuspend (&oset); 102 103 sigaction(SIGALRM, &oact, NULL); 104 sigprocmask(SIG_SETMASK, &oset, NULL); 105 106 (void) setitimer(ITIMER_REAL, &oitv, &itv); 107 108 if (timerisset(&diff)) 109 __timeradd(&itv.it_value, &diff); 110 111 return (itv.it_value.tv_sec); 112 } 113 114 static void 115 sleephandler() 116 { 117 } 118