4.3BSD - /usr/src/lib/libc/gen/sleep.c

   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: #if defined(LIBC_SCCS) && !defined(lint)
   8: static char sccsid[] = "@(#)sleep.c	5.2 (Berkeley) 3/9/86";
   9: #endif LIBC_SCCS and 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: }

Defined functions

Defined variables

Defined macros