1 /* $NetBSD: sleep.c,v 1.13 1995/10/26 22:07:00 pk 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: sleep.c,v 1.13 1995/10/26 22:07:00 pk Exp $"; 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 static volatile int ringring; 49 50 unsigned int 51 sleep(seconds) 52 unsigned int seconds; 53 { 54 struct itimerval itv, oitv; 55 struct sigaction act, oact; 56 struct timeval diff; 57 sigset_t set, oset; 58 static void sleephandler(); 59 60 if (!seconds) 61 return 0; 62 63 sigemptyset(&set); 64 sigaddset(&set, SIGALRM); 65 sigprocmask(SIG_BLOCK, &set, &oset); 66 67 act.sa_handler = sleephandler; 68 act.sa_flags = 0; 69 sigemptyset(&act.sa_mask); 70 sigaction(SIGALRM, &act, &oact); 71 72 timerclear(&itv.it_interval); 73 itv.it_value.tv_sec = seconds; 74 itv.it_value.tv_usec = 0; 75 timerclear(&diff); 76 setitimer(ITIMER_REAL, &itv, &oitv); 77 78 if (timerisset(&oitv.it_value)) { 79 if (timercmp(&oitv.it_value, &itv.it_value, >)) { 80 timersub(&oitv.it_value, &itv.it_value, &oitv.it_value); 81 } else { 82 /* 83 * The existing timer was scheduled to fire 84 * before ours, so we compute the time diff 85 * so we can add it back in the end. 86 */ 87 timersub(&itv.it_value, &oitv.it_value, &diff); 88 itv.it_value = oitv.it_value; 89 /* 90 * This is a hack, but we must have time to return 91 * from the setitimer after the alarm or else it'll 92 * be restarted. And, anyway, sleep never did 93 * anything more than this before. 94 */ 95 oitv.it_value.tv_sec = 1; 96 oitv.it_value.tv_usec = 0; 97 98 setitimer(ITIMER_REAL, &itv, NULL); 99 } 100 } 101 102 set = oset; 103 sigdelset(&set, SIGALRM); 104 ringring = 0; 105 (void) sigsuspend(&set); 106 107 if (ringring) { 108 /* Our alarm went off; timer is not currently running */ 109 sigaction(SIGALRM, &oact, NULL); 110 sigprocmask(SIG_SETMASK, &oset, NULL); 111 (void) setitimer(ITIMER_REAL, &oitv, &itv); 112 } else { 113 struct itimerval nulltv; 114 /* 115 * Interrupted by other signal; allow for pending 116 * SIGALRM to be processed before resetting handler, 117 * after first turning off the timer. 118 */ 119 timerclear(&nulltv.it_interval); 120 timerclear(&nulltv.it_value); 121 (void) setitimer(ITIMER_REAL, &nulltv, &itv); 122 sigprocmask(SIG_SETMASK, &oset, NULL); 123 sigaction(SIGALRM, &oact, NULL); 124 (void) setitimer(ITIMER_REAL, &oitv, NULL); 125 } 126 127 if (timerisset(&diff)) 128 timeradd(&itv.it_value, &diff, &itv.it_value); 129 130 return (itv.it_value.tv_sec); 131 } 132 133 static void 134 sleephandler() 135 { 136 ringring = 1; 137 } 138