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/* MIT License
*
* Copyright (c) 1998 Massachusetts Institute of Technology
* Copyright (c) The c-ares project and its contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* SPDX-License-Identifier: MIT
*/
#include "ares_private.h"
int ares_fds(const ares_channel_t *channel, fd_set *read_fds, fd_set *write_fds)
{
ares_socket_t nfds;
ares__slist_node_t *snode;
/* Are there any active queries? */
size_t active_queries;
if (channel == NULL || read_fds == NULL || write_fds == NULL) {
return 0;
}
ares__channel_lock(channel);
active_queries = ares__llist_len(channel->all_queries);
nfds = 0;
for (snode = ares__slist_node_first(channel->servers); snode != NULL;
snode = ares__slist_node_next(snode)) {
ares_server_t *server = ares__slist_node_val(snode);
ares__llist_node_t *node;
for (node = ares__llist_node_first(server->connections); node != NULL;
node = ares__llist_node_next(node)) {
const ares_conn_t *conn = ares__llist_node_val(node);
if (!active_queries && !(conn->flags & ARES_CONN_FLAG_TCP)) {
continue;
}
/* Silence coverity, shouldn't be possible */
if (conn->fd == ARES_SOCKET_BAD) {
continue;
}
/* Always wait on read */
FD_SET(conn->fd, read_fds);
if (conn->fd >= nfds) {
nfds = conn->fd + 1;
}
/* TCP only wait on write if we have buffered data */
if (conn->flags & ARES_CONN_FLAG_TCP && ares__buf_len(server->tcp_send)) {
FD_SET(conn->fd, write_fds);
}
}
}
ares__channel_unlock(channel);
return (int)nfds;
}
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