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1.1 root 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: #ifndef lint
12: static char SccsId[] = "@(#)clock.c 5.4 (Berkeley) 12/17/85";
13: #endif not lint
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(0) & ~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: sleep(intvl)
219: unsigned int intvl;
220: {
221: extern endsleep();
222:
223: if (intvl == 0)
224: return;
225: SleepDone = FALSE;
226: (void) setevent((time_t) intvl, endsleep, 0);
227: while (!SleepDone)
228: pause();
229: }
230:
231: static
232: endsleep()
233: {
234: SleepDone = TRUE;
235: }
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