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Annotation of 43BSDReno/lib/libc/gen/usleep.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1989 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted
        !             6:  * provided that: (1) source distributions retain this entire copyright
        !             7:  * notice and comment, and (2) distributions including binaries display
        !             8:  * the following acknowledgement:  ``This product includes software
        !             9:  * developed by the University of California, Berkeley and its contributors''
        !            10:  * in the documentation or other materials provided with the distribution
        !            11:  * and in all advertising materials mentioning features or use of this
        !            12:  * software. Neither the name of the University nor the names of its
        !            13:  * contributors may be used to endorse or promote products derived
        !            14:  * from this software without specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #if defined(LIBC_SCCS) && !defined(lint)
        !            21: static char sccsid[] = "@(#)usleep.c   5.5 (Berkeley) 6/1/90";
        !            22: #endif /* LIBC_SCCS and not lint */
        !            23: 
        !            24: #include <sys/time.h>
        !            25: #include <sys/signal.h>
        !            26: 
        !            27: #define        TICK    10000           /* system clock resolution in microseconds */
        !            28: #define        USPS    1000000         /* number of microseconds in a second */
        !            29: 
        !            30: #define        setvec(vec, a) \
        !            31:        vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0
        !            32: 
        !            33: static int ringring;
        !            34: 
        !            35: usleep(useconds)
        !            36:        unsigned int useconds;
        !            37: {
        !            38:        register struct itimerval *itp;
        !            39:        struct itimerval itv, oitv;
        !            40:        struct sigvec vec, ovec;
        !            41:        long omask;
        !            42:        void sleephandler();
        !            43: 
        !            44:        itp = &itv;
        !            45:        if (!useconds)
        !            46:                return;
        !            47:        timerclear(&itp->it_interval);
        !            48:        timerclear(&itp->it_value);
        !            49:        if (setitimer(ITIMER_REAL, itp, &oitv) < 0)
        !            50:                return;
        !            51:        itp->it_value.tv_sec = useconds / USPS;
        !            52:        itp->it_value.tv_usec = useconds % USPS;
        !            53:        if (timerisset(&oitv.it_value)) {
        !            54:                if (timercmp(&oitv.it_value, &itp->it_value, >)) {
        !            55:                        oitv.it_value.tv_sec -= itp->it_value.tv_sec;
        !            56:                        oitv.it_value.tv_usec -= itp->it_value.tv_usec;
        !            57:                        if (oitv.it_value.tv_usec < 0) {
        !            58:                                oitv.it_value.tv_usec += USPS;
        !            59:                                oitv.it_value.tv_sec--;
        !            60:                        }
        !            61:                } else {
        !            62:                        itp->it_value = oitv.it_value;
        !            63:                        oitv.it_value.tv_sec = 0;
        !            64:                        oitv.it_value.tv_usec = 2 * TICK;
        !            65:                }
        !            66:        }
        !            67:        setvec(vec, sleephandler);
        !            68:        (void) sigvec(SIGALRM, &vec, &ovec);
        !            69:        omask = sigblock(sigmask(SIGALRM));
        !            70:        ringring = 0;
        !            71:        (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0);
        !            72:        while (!ringring)
        !            73:                sigpause(omask &~ sigmask(SIGALRM));
        !            74:        (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0);
        !            75:        (void) sigsetmask(omask);
        !            76:        (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0);
        !            77: }
        !            78: 
        !            79: static void
        !            80: sleephandler()
        !            81: {
        !            82:        ringring = 1;
        !            83: }

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