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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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