1: /*
   2: **  Sendmail
   3: **  Copyright (c) 1983  Eric P. Allman
   4: **  Berkeley, California
   5: **
   6: **  Copyright (c) 1983 Regents of the University of California.
   7: **  All rights reserved.  The Berkeley software License Agreement
   8: **  specifies the terms and conditions for redistribution.
   9: */
  10: 
  11: #if !defined(lint) && !defined(NOSCCS)
  12: static char SccsId[] = "@(#)clock.c	5.4.2 (2.11BSD) 1997/10/3";
  13: #endif
  14: 
  15: # include "sendmail.h"
  16: # include <signal.h>
  17: 
  18: /*
  19: **  SETEVENT -- set an event to happen at a specific time.
  20: **
  21: **	Events are stored in a sorted list for fast processing.
  22: **	An event only applies to the process that set it.
  23: **
  24: **	Parameters:
  25: **		intvl -- intvl until next event occurs.
  26: **		func -- function to call on event.
  27: **		arg -- argument to func on event.
  28: **
  29: **	Returns:
  30: **		none.
  31: **
  32: **	Side Effects:
  33: **		none.
  34: */
  35: 
  36: EVENT *
  37: setevent(intvl, func, arg)
  38:     time_t intvl;
  39:     int (*func)();
  40:     int arg;
  41: {
  42:     register EVENT **evp;
  43:     register EVENT *ev;
  44:     auto time_t now;
  45:     extern tick();
  46: 
  47: # ifdef DEBUG
  48:     if (intvl <= 0)
  49:     {
  50:         syserr("setevent: intvl=%ld\n", intvl);
  51:         return (NULL);
  52:     }
  53: # endif DEBUG
  54: 
  55:     (void) time(&now);
  56: 
  57:     /* search event queue for correct position */
  58:     for (evp = &EventQueue; (ev = *evp) != NULL; evp = &ev->ev_link)
  59:     {
  60:         if (ev->ev_time >= now + intvl)
  61:             break;
  62:     }
  63: 
  64:     /* insert new event */
  65:     ev = (EVENT *) xalloc(sizeof *ev);
  66:     ev->ev_time = now + intvl;
  67:     ev->ev_func = func;
  68:     ev->ev_arg = arg;
  69:     ev->ev_pid = getpid();
  70:     ev->ev_link = *evp;
  71:     *evp = ev;
  72: 
  73: # ifdef DEBUG
  74:     if (tTd(5, 5))
  75:         printf("setevent: intvl=%ld, for=%ld, func=%x, arg=%d, ev=%x\n",
  76:             intvl, now + intvl, func, arg, ev);
  77: # endif DEBUG
  78: 
  79:     tick();
  80:     return (ev);
  81: }
  82: /*
  83: **  CLREVENT -- remove an event from the event queue.
  84: **
  85: **	Parameters:
  86: **		ev -- pointer to event to remove.
  87: **
  88: **	Returns:
  89: **		none.
  90: **
  91: **	Side Effects:
  92: **		arranges for event ev to not happen.
  93: */
  94: 
  95: clrevent(ev)
  96:     register EVENT *ev;
  97: {
  98:     register EVENT **evp;
  99: 
 100: # ifdef DEBUG
 101:     if (tTd(5, 5))
 102:         printf("clrevent: ev=%x\n", ev);
 103: # endif DEBUG
 104:     if (ev == NULL)
 105:         return;
 106: 
 107:     /* find the parent event */
 108:     (void) signal(SIGALRM, SIG_IGN);
 109:     for (evp = &EventQueue; *evp != NULL; evp = &(*evp)->ev_link)
 110:     {
 111:         if (*evp == ev)
 112:             break;
 113:     }
 114: 
 115:     /* now remove it */
 116:     if (*evp != NULL)
 117:     {
 118:         *evp = ev->ev_link;
 119:         free((char *) ev);
 120:     }
 121: 
 122:     /* restore clocks and pick up anything spare */
 123:     tick();
 124: }
 125: /*
 126: **  TICK -- take a clock tick
 127: **
 128: **	Called by the alarm clock.  This routine runs events as needed.
 129: **
 130: **	Parameters:
 131: **		none.
 132: **
 133: **	Returns:
 134: **		none.
 135: **
 136: **	Side Effects:
 137: **		calls the next function in EventQueue.
 138: */
 139: 
 140: tick()
 141: {
 142:     register time_t now;
 143:     register EVENT *ev;
 144:     int mypid = getpid();
 145: 
 146:     (void) signal(SIGALRM, SIG_IGN);
 147:     (void) alarm(0);
 148:     now = curtime();
 149: 
 150: # ifdef DEBUG
 151:     if (tTd(5, 4))
 152:         printf("tick: now=%ld\n", now);
 153: # endif DEBUG
 154: 
 155:     while ((ev = EventQueue) != NULL &&
 156:            (ev->ev_time <= now || ev->ev_pid != mypid))
 157:     {
 158:         int (*f)();
 159:         int arg;
 160:         int pid;
 161: 
 162:         /* process the event on the top of the queue */
 163:         ev = EventQueue;
 164:         EventQueue = EventQueue->ev_link;
 165: # ifdef DEBUG
 166:         if (tTd(5, 6))
 167:             printf("tick: ev=%x, func=%x, arg=%d, pid=%d\n", ev,
 168:                 ev->ev_func, ev->ev_arg, ev->ev_pid);
 169: # endif DEBUG
 170: 
 171:         /* we must be careful in here because ev_func may not return */
 172:         (void) signal(SIGALRM, tick);
 173: #ifdef SIGVTALRM
 174:         /* reset 4.2bsd signal mask to allow future alarms */
 175:         (void) sigsetmask(sigblock(0L) & ~sigmask(SIGALRM));
 176: #endif SIGVTALRM
 177: 
 178:         f = ev->ev_func;
 179:         arg = ev->ev_arg;
 180:         pid = ev->ev_pid;
 181:         free((char *) ev);
 182:         if (pid != getpid())
 183:             continue;
 184:         if (EventQueue != NULL)
 185:         {
 186:             if (EventQueue->ev_time > now)
 187:                 (void) alarm((unsigned) (EventQueue->ev_time - now));
 188:             else
 189:                 (void) alarm(3);
 190:         }
 191:         (*f)(arg);
 192:         (void) alarm(0);
 193:         now = curtime();
 194:     }
 195:     (void) signal(SIGALRM, tick);
 196:     if (EventQueue != NULL)
 197:         (void) alarm((unsigned) (EventQueue->ev_time - now));
 198: }
 199: /*
 200: **  SLEEP -- a version of sleep that works with this stuff
 201: **
 202: **	Because sleep uses the alarm facility, I must reimplement
 203: **	it here.
 204: **
 205: **	Parameters:
 206: **		intvl -- time to sleep.
 207: **
 208: **	Returns:
 209: **		none.
 210: **
 211: **	Side Effects:
 212: **		waits for intvl time.  However, other events can
 213: **		be run during that interval.
 214: */
 215: 
 216: static bool SleepDone;
 217: 
 218: unsigned int
 219: sleep(intvl)
 220:     unsigned int intvl;
 221: {
 222:     extern endsleep();
 223: 
 224:     if (intvl == 0)
 225:         return;
 226:     SleepDone = FALSE;
 227:     (void) setevent((time_t) intvl, endsleep, 0);
 228:     while (!SleepDone)
 229:         pause();
 230: }
 231: 
 232: endsleep()
 233: {
 234:     SleepDone = TRUE;
 235: }
Last modified: 1997-10-03
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