1 /* 2 * Copyright (c) 1980 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 */ 6 7 #ifndef lint 8 static char sccsid[] = "@(#)sleep.c 5.1 (Berkeley) 05/30/85"; 9 #endif not lint 10 11 #include <sys/time.h> 12 #include <signal.h> 13 14 #define setvec(vec, a) \ 15 vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 16 17 static int ringring; 18 19 sleep(n) 20 unsigned n; 21 { 22 int sleepx(), omask; 23 struct itimerval itv, oitv; 24 register struct itimerval *itp = &itv; 25 struct sigvec vec, ovec; 26 27 if (n == 0) 28 return; 29 timerclear(&itp->it_interval); 30 timerclear(&itp->it_value); 31 if (setitimer(ITIMER_REAL, itp, &oitv) < 0) 32 return; 33 itp->it_value.tv_sec = n; 34 if (timerisset(&oitv.it_value)) { 35 if (timercmp(&oitv.it_value, &itp->it_value, >)) 36 oitv.it_value.tv_sec -= itp->it_value.tv_sec; 37 else { 38 itp->it_value = oitv.it_value; 39 /* 40 * This is a hack, but we must have time to 41 * return from the setitimer after the alarm 42 * or else it'll be restarted. And, anyway, 43 * sleep never did anything more than this before. 44 */ 45 oitv.it_value.tv_sec = 1; 46 oitv.it_value.tv_usec = 0; 47 } 48 } 49 setvec(vec, sleepx); 50 (void) sigvec(SIGALRM, &vec, &ovec); 51 omask = sigblock(sigmask(SIGALRM)); 52 ringring = 0; 53 (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); 54 while (!ringring) 55 sigpause(omask &~ sigmask(SIGALRM)); 56 (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); 57 (void) sigsetmask(omask); 58 (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); 59 } 60 61 static 62 sleepx() 63 { 64 65 ringring = 1; 66 } 67