2 * Copyright (c) 1997-1999 Erez Zadok
3 * Copyright (c) 1989 Jan-Simon Pendry
4 * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
5 * Copyright (c) 1989 The Regents of the University of California.
8 * This code is derived from software contributed to Berkeley by
9 * Jan-Simon Pendry at Imperial College, London.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgment:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 * $Id: clock.c,v 1.3 1999/01/13 23:30:58 ezk Exp $
48 * Modeled on kernel object of the same name.
49 * See usual references.
51 * Use of a heap-based mechanism was rejected:
52 * 1. more complex implementation needed.
53 * 2. not obvious that a list is too slow for Amd.
58 #endif /* HAVE_CONFIG_H */
62 int timeout(u_int secs, void (*fn) (voidp), voidp closure);
63 void reschedule_timeouts(time_t now, time_t then);
65 typedef struct callout callout;
67 callout *c_next; /* List of callouts */
68 void (*c_fn) (voidp); /* Function to call */
69 voidp c_closure; /* Closure to pass to call */
70 time_t c_time; /* Time of call */
71 int c_id; /* Unique identifier */
74 static callout callouts; /* List of pending callouts */
75 static callout *free_callouts; /* Cache of free callouts */
76 static int nfree_callouts; /* Number on free list */
77 static int callout_id; /* Next free callout identifier */
79 time_t next_softclock; /* Time of next call to softclock() */
83 * Number of callout slots we keep on the free list
85 #define CALLOUT_FREE_SLOP 10
88 * Global assumption: valid id's are non-zero.
90 #define CID_ALLOC(struct ) (++callout_id)
97 callout *cp = free_callouts;
101 free_callouts = free_callouts->c_next;
104 return ALLOC(struct callout);
109 free_callout(callout *cp)
111 if (nfree_callouts > CALLOUT_FREE_SLOP) {
114 cp->c_next = free_callouts;
122 * Schedule a callout.
124 * (*fn)(closure) will be called at clocktime() + secs
127 timeout(u_int secs, void (*fn) (voidp), voidp closure)
130 time_t t = clocktime() + secs;
133 * Allocate and fill in a new callout structure
135 callout *cpnew = alloc_callout();
136 cpnew->c_closure = closure;
139 cpnew->c_id = CID_ALLOC(struct );
141 if (t < next_softclock)
145 * Find the correct place in the list
147 for (cp = &callouts; (cp2 = cp->c_next); cp = cp2)
148 if (cp2->c_time >= t)
158 * Return callout identifier
165 * De-schedule a callout
171 for (cp = &callouts; (cp2 = cp->c_next); cp = cp2) {
172 if (cp2->c_id == id) {
173 cp->c_next = cp2->c_next;
182 * Reschedule after clock changed
185 reschedule_timeouts(time_t now, time_t then)
189 for (cp = callouts.c_next; cp; cp = cp->c_next) {
190 if (cp->c_time >= now && cp->c_time <= then) {
191 plog(XLOG_WARNING, "job %d rescheduled to run immediately", cp->c_id);
193 dlog("rescheduling job %d back %ld seconds",
194 cp->c_id, (long) (cp->c_time - now));
196 next_softclock = cp->c_time = now;
212 if (task_notify_todo)
218 * While there are more callouts waiting...
220 while ((cp = callouts.c_next) && cp->c_time <= now) {
222 * Extract first from list, save fn & closure and
223 * unlink callout from list and free.
224 * Finally call function.
226 * The free is done first because
227 * it is quite common that the
228 * function will call timeout()
229 * and try to allocate a callout
231 void (*fn) (voidp) = cp->c_fn;
232 voidp closure = cp->c_closure;
234 callouts.c_next = cp->c_next;
239 } while (task_notify_todo);
242 * Return number of seconds to next event,
243 * or 0 if there is no event.
245 if ((cp = callouts.c_next))
246 return cp->c_time - now;