1
2 /* Copyright (C) 2004 by Daniel Stenberg et al
3 *
4 * Permission to use, copy, modify, and distribute this software and its
5 * documentation for any purpose and without fee is hereby granted, provided
6 * that the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation, and that the name of M.I.T. not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. M.I.T. makes no representations about the
11 * suitability of this software for any purpose. It is provided "as is"
12 * without express or implied warranty.
13 */
14
15 #include "ares_setup.h"
16 #include <assert.h>
17
18 #include "ares.h"
19 #include "ares_private.h"
20
21 /*
22 * ares_cancel() cancels all ongoing requests/resolves that might be going on
23 * on the given channel. It does NOT kill the channel, use ares_destroy() for
24 * that.
25 */
ares_cancel(ares_channel channel)26 void ares_cancel(ares_channel channel)
27 {
28 struct query *query;
29 struct list_node list_head_copy;
30 struct list_node* list_head;
31 struct list_node* list_node;
32 int i;
33
34 if (!ares__is_list_empty(&(channel->all_queries)))
35 {
36 /* Swap list heads, so that only those queries which were present on entry
37 * into this function are cancelled. New queries added by callbacks of
38 * queries being cancelled will not be cancelled themselves.
39 */
40 list_head = &(channel->all_queries);
41 list_head_copy.prev = list_head->prev;
42 list_head_copy.next = list_head->next;
43 list_head_copy.prev->next = &list_head_copy;
44 list_head_copy.next->prev = &list_head_copy;
45 list_head->prev = list_head;
46 list_head->next = list_head;
47 for (list_node = list_head_copy.next; list_node != &list_head_copy; )
48 {
49 query = list_node->data;
50 list_node = list_node->next; /* since we're deleting the query */
51 query->callback(query->arg, ARES_ECANCELLED, 0, NULL, 0);
52 ares__free_query(query);
53 }
54 }
55 if (!(channel->flags & ARES_FLAG_STAYOPEN) && ares__is_list_empty(&(channel->all_queries)))
56 {
57 if (channel->servers)
58 {
59 for (i = 0; i < channel->nservers; i++)
60 ares__close_sockets(channel, &channel->servers[i]);
61 }
62 }
63 }
64