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1.1 ! root 1: /* ! 2: * Copyright (c) 1985 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: #if defined(LIBC_SCCS) && !defined(lint) ! 8: static char sccsid[] = "@(#)usleep.c 5.3 (Berkeley) 9/30/87"; ! 9: #endif LIBC_SCCS and not lint ! 10: ! 11: #include <sys/time.h> ! 12: #include <signal.h> ! 13: ! 14: #define USPS 1000000 /* number of microseconds in a second */ ! 15: #define TICK 10000 /* system clock resolution in microseconds */ ! 16: ! 17: #define setvec(vec, a) \ ! 18: vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0 ! 19: ! 20: static int ringring; ! 21: ! 22: usleep(n) ! 23: unsigned n; ! 24: { ! 25: int sleepx(); ! 26: long omask; ! 27: struct itimerval itv, oitv; ! 28: register struct itimerval *itp = &itv; ! 29: struct sigvec vec, ovec; ! 30: ! 31: if (n == 0) ! 32: return; ! 33: timerclear(&itp->it_interval); ! 34: timerclear(&itp->it_value); ! 35: if (setitimer(ITIMER_REAL, itp, &oitv) < 0) ! 36: return; ! 37: itp->it_value.tv_sec = n / USPS; ! 38: itp->it_value.tv_usec = n % USPS; ! 39: if (timerisset(&oitv.it_value)) { ! 40: if (timercmp(&oitv.it_value, &itp->it_value, >)) { ! 41: oitv.it_value.tv_sec -= itp->it_value.tv_sec; ! 42: oitv.it_value.tv_usec -= itp->it_value.tv_usec; ! 43: if (oitv.it_value.tv_usec < 0) { ! 44: oitv.it_value.tv_usec += USPS; ! 45: oitv.it_value.tv_sec--; ! 46: } ! 47: } else { ! 48: itp->it_value = oitv.it_value; ! 49: oitv.it_value.tv_sec = 0; ! 50: oitv.it_value.tv_usec = 2 * TICK; ! 51: } ! 52: } ! 53: setvec(vec, sleepx); ! 54: (void) sigvec(SIGALRM, &vec, &ovec); ! 55: omask = sigblock(sigmask(SIGALRM)); ! 56: ringring = 0; ! 57: (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0); ! 58: while (!ringring) ! 59: sigpause(omask &~ sigmask(SIGALRM)); ! 60: (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0); ! 61: (void) sigsetmask(omask); ! 62: (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0); ! 63: } ! 64: ! 65: static ! 66: sleepx() ! 67: { ! 68: ! 69: ringring = 1; ! 70: }
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