1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 *
4 * Permission to use, copy, modify, and distribute this
5 * software and its documentation for any purpose and without
6 * fee is hereby granted, provided that the above copyright
7 * notice appear in all copies and that both that copyright
8 * notice and this permission notice appear in supporting
9 * documentation, and that the name of M.I.T. not be used in
10 * advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.
12 * M.I.T. makes no representations about the suitability of
13 * this software for any purpose. It is provided "as is"
14 * without express or implied warranty.
15 */
16
17 #include "ares_setup.h"
18
19 #ifdef HAVE_SYS_TIME_H
20 #include <sys/time.h>
21 #endif
22
23 #include <time.h>
24
25 #include "ares.h"
26 #include "ares_private.h"
27
28 /* WARNING: Beware that this is linear in the number of outstanding
29 * requests! You are probably far better off just calling ares_process()
30 * once per second, rather than calling ares_timeout() to figure out
31 * when to next call ares_process().
32 */
ares_timeout(ares_channel channel,struct timeval * maxtv,struct timeval * tvbuf)33 struct timeval *ares_timeout(ares_channel channel, struct timeval *maxtv,
34 struct timeval *tvbuf)
35 {
36 struct query *query;
37 struct list_node* list_head;
38 struct list_node* list_node;
39 struct timeval now;
40 struct timeval nextstop;
41 long offset, min_offset;
42
43 /* No queries, no timeout (and no fetch of the current time). */
44 if (ares__is_list_empty(&(channel->all_queries)))
45 return maxtv;
46
47 /* Find the minimum timeout for the current set of queries. */
48 now = ares__tvnow();
49 min_offset = -1;
50
51 list_head = &(channel->all_queries);
52 for (list_node = list_head->next; list_node != list_head;
53 list_node = list_node->next)
54 {
55 query = list_node->data;
56 if (query->timeout.tv_sec == 0)
57 continue;
58 offset = ares__timeoffset(&now, &query->timeout);
59 if (offset < 0)
60 offset = 0;
61 if (min_offset == -1 || offset < min_offset)
62 min_offset = offset;
63 }
64
65 if(min_offset != -1) {
66 nextstop.tv_sec = min_offset/1000;
67 nextstop.tv_usec = (min_offset%1000)*1000;
68 }
69
70 /* If we found a minimum timeout and it's sooner than the one specified in
71 * maxtv (if any), return it. Otherwise go with maxtv.
72 */
73 if (min_offset != -1 && (!maxtv || ares__timedout(maxtv, &nextstop)))
74 {
75 *tvbuf = nextstop;
76 return tvbuf;
77 }
78 else
79 return maxtv;
80 }
81