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Annotation of 42BSD/usr.lib/sendmail/src/clock.c, revision 1.1

1.1     ! root        1: # include "sendmail.h"
        !             2: # include <signal.h>
        !             3: 
        !             4: SCCSID(@(#)clock.c     4.1             7/25/83);
        !             5: 
        !             6: /*
        !             7: **  SETEVENT -- set an event to happen at a specific time.
        !             8: **
        !             9: **     Events are stored in a sorted list for fast processing.
        !            10: **     An event only applies to the process that set it.
        !            11: **
        !            12: **     Parameters:
        !            13: **             intvl -- intvl until next event occurs.
        !            14: **             func -- function to call on event.
        !            15: **             arg -- argument to func on event.
        !            16: **
        !            17: **     Returns:
        !            18: **             none.
        !            19: **
        !            20: **     Side Effects:
        !            21: **             none.
        !            22: */
        !            23: 
        !            24: EVENT *
        !            25: setevent(intvl, func, arg)
        !            26:        time_t intvl;
        !            27:        int (*func)();
        !            28:        int arg;
        !            29: {
        !            30:        register EVENT **evp;
        !            31:        register EVENT *ev;
        !            32:        auto time_t now;
        !            33:        extern tick();
        !            34: 
        !            35: # ifdef DEBUG
        !            36:        if (intvl <= 0)
        !            37:        {
        !            38:                syserr("setevent: intvl=%ld\n", intvl);
        !            39:                return (NULL);
        !            40:        }
        !            41: # endif DEBUG
        !            42: 
        !            43:        (void) time(&now);
        !            44: 
        !            45:        /* search event queue for correct position */
        !            46:        for (evp = &EventQueue; (ev = *evp) != NULL; evp = &ev->ev_link)
        !            47:        {
        !            48:                if (ev->ev_time >= now + intvl)
        !            49:                        break;
        !            50:        }
        !            51: 
        !            52:        /* insert new event */
        !            53:        ev = (EVENT *) xalloc(sizeof *ev);
        !            54:        ev->ev_time = now + intvl;
        !            55:        ev->ev_func = func;
        !            56:        ev->ev_arg = arg;
        !            57:        ev->ev_pid = getpid();
        !            58:        ev->ev_link = *evp;
        !            59:        *evp = ev;
        !            60: 
        !            61: # ifdef DEBUG
        !            62:        if (tTd(5, 5))
        !            63:                printf("setevent: intvl=%ld, for=%ld, func=%x, arg=%d, ev=%x\n",
        !            64:                        intvl, now + intvl, func, arg, ev);
        !            65: # endif DEBUG
        !            66: 
        !            67:        tick();
        !            68:        return (ev);
        !            69: }
        !            70: /*
        !            71: **  CLREVENT -- remove an event from the event queue.
        !            72: **
        !            73: **     Parameters:
        !            74: **             ev -- pointer to event to remove.
        !            75: **
        !            76: **     Returns:
        !            77: **             none.
        !            78: **
        !            79: **     Side Effects:
        !            80: **             arranges for event ev to not happen.
        !            81: */
        !            82: 
        !            83: clrevent(ev)
        !            84:        register EVENT *ev;
        !            85: {
        !            86:        register EVENT **evp;
        !            87: 
        !            88: # ifdef DEBUG
        !            89:        if (tTd(5, 5))
        !            90:                printf("clrevent: ev=%x\n", ev);
        !            91: # endif DEBUG
        !            92:        if (ev == NULL)
        !            93:                return;
        !            94: 
        !            95:        /* find the parent event */
        !            96:        (void) signal(SIGALRM, SIG_IGN);
        !            97:        for (evp = &EventQueue; *evp != NULL; evp = &(*evp)->ev_link)
        !            98:        {
        !            99:                if (*evp == ev)
        !           100:                        break;
        !           101:        }
        !           102: 
        !           103:        /* now remove it */
        !           104:        if (*evp != NULL)
        !           105:        {
        !           106:                *evp = ev->ev_link;
        !           107:                free((char *) ev);
        !           108:        }
        !           109: 
        !           110:        /* restore clocks and pick up anything spare */
        !           111:        tick();
        !           112: }
        !           113: /*
        !           114: **  TICK -- take a clock tick
        !           115: **
        !           116: **     Called by the alarm clock.  This routine runs events as needed.
        !           117: **
        !           118: **     Parameters:
        !           119: **             none.
        !           120: **
        !           121: **     Returns:
        !           122: **             none.
        !           123: **
        !           124: **     Side Effects:
        !           125: **             calls the next function in EventQueue.
        !           126: */
        !           127: 
        !           128: tick()
        !           129: {
        !           130:        register time_t now;
        !           131:        register EVENT *ev;
        !           132: 
        !           133:        (void) signal(SIGALRM, SIG_IGN);
        !           134:        (void) alarm(0);
        !           135:        now = curtime();
        !           136: 
        !           137: # ifdef DEBUG
        !           138:        if (tTd(5, 4))
        !           139:                printf("tick: now=%ld\n", now);
        !           140: # endif DEBUG
        !           141: 
        !           142:        while ((ev = EventQueue) != NULL &&
        !           143:               (ev->ev_time <= now || ev->ev_pid != getpid()))
        !           144:        {
        !           145:                int (*f)(), a;
        !           146: 
        !           147:                /* process the event on the top of the queue */
        !           148:                ev = EventQueue;
        !           149:                EventQueue = EventQueue->ev_link;
        !           150: # ifdef DEBUG
        !           151:                if (tTd(5, 6))
        !           152:                        printf("tick: ev=%x, func=%x, arg=%d, pid=%d\n", ev,
        !           153:                                ev->ev_func, ev->ev_arg, ev->ev_pid);
        !           154: # endif DEBUG
        !           155: 
        !           156:                /* we must be careful in here because ev_func may not return */
        !           157:                (void) signal(SIGALRM, tick);
        !           158:                f = ev->ev_func;
        !           159:                a = ev->ev_arg;
        !           160:                free((char *) ev);
        !           161:                if (ev->ev_pid != getpid())
        !           162:                        continue;
        !           163:                if (EventQueue != NULL)
        !           164:                {
        !           165:                        if (EventQueue->ev_time > now)
        !           166:                                (void) alarm((unsigned) (EventQueue->ev_time - now));
        !           167:                        else
        !           168:                                (void) alarm(3);
        !           169:                }
        !           170:                (*f)(a);
        !           171:                (void) alarm(0);
        !           172:                now = curtime();
        !           173:        }
        !           174:        (void) signal(SIGALRM, tick);
        !           175:        if (EventQueue != NULL)
        !           176:                (void) alarm((unsigned) (EventQueue->ev_time - now));
        !           177: }
        !           178: /*
        !           179: **  SLEEP -- a version of sleep that works with this stuff
        !           180: **
        !           181: **     Because sleep uses the alarm facility, I must reimplement
        !           182: **     it here.
        !           183: **
        !           184: **     Parameters:
        !           185: **             intvl -- time to sleep.
        !           186: **
        !           187: **     Returns:
        !           188: **             none.
        !           189: **
        !           190: **     Side Effects:
        !           191: **             waits for intvl time.  However, other events can
        !           192: **             be run during that interval.
        !           193: */
        !           194: 
        !           195: static bool    SleepDone;
        !           196: 
        !           197: sleep(intvl)
        !           198:        int intvl;
        !           199: {
        !           200:        extern endsleep();
        !           201: 
        !           202:        if (intvl == 0)
        !           203:                return;
        !           204:        SleepDone = FALSE;
        !           205:        (void) setevent((time_t) intvl, endsleep, 0);
        !           206:        while (!SleepDone)
        !           207:                pause();
        !           208: }
        !           209: 
        !           210: static
        !           211: endsleep()
        !           212: {
        !           213:        SleepDone = TRUE;
        !           214: }

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