1 #ifndef lint 2 static char sccsid[] = "@(#)sleep.c 4.7 (Berkeley) 12/08/84"; 3 #endif 4 5 #include <sys/time.h> 6 #include <signal.h> 7 8 #define setvec(vec, a) \ 9 vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 10 11 static int ringring; 12 13 sleep(n) 14 unsigned n; 15 { 16 int sleepx(), omask; 17 struct itimerval itv, oitv; 18 register struct itimerval *itp = &itv; 19 struct sigvec vec, ovec; 20 21 if (n == 0) 22 return; 23 timerclear(&itp->it_interval); 24 timerclear(&itp->it_value); 25 if (setitimer(ITIMER_REAL, itp, &oitv) < 0) 26 return; 27 itp->it_value.tv_sec = n; 28 if (timerisset(&oitv.it_value)) { 29 if (timercmp(&oitv.it_value, &itp->it_value, >)) 30 oitv.it_value.tv_sec -= itp->it_value.tv_sec; 31 else { 32 itp->it_value = oitv.it_value; 33 /* 34 * This is a hack, but we must have time to 35 * return from the setitimer after the alarm 36 * or else it'll be restarted. And, anyway, 37 * sleep never did anything more than this before. 38 */ 39 oitv.it_value.tv_sec = 1; 40 oitv.it_value.tv_usec = 0; 41 } 42 } 43 setvec(vec, sleepx); 44 (void) sigvec(SIGALRM, &vec, &ovec); 45 omask = sigblock(sigmask(SIGALRM)); 46 ringring = 0; 47 (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); 48 while (!ringring) 49 sigpause(omask &~ sigmask(SIGALRM)); 50 (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); 51 (void) sigsetmask(omask); 52 (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); 53 } 54 55 static 56 sleepx() 57 { 58 59 ringring = 1; 60 } 61