Annotation of 43BSD/lib/libc/gen/sleep.c, revision 1.1.1.1

1.1       root        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: }

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