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/* MIT License
*
* Copyright (c) 2024 Brad House
*
* 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
*/
/* Some systems might default to something low like 256 (NetBSD), lets define
* this to assist. Really, no one should be using select, but lets be safe
* anyhow */
#define FD_SETSIZE 4096
#include "ares_private.h"
#include "ares_event.h"
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
/* All systems have select(), but not all have a way to wake, so we require
* pipe() to wake the select() */
#if defined(HAVE_PIPE)
static ares_bool_t ares_evsys_select_init(ares_event_thread_t *e)
{
e->ev_signal = ares_pipeevent_create(e);
if (e->ev_signal == NULL) {
return ARES_FALSE; /* LCOV_EXCL_LINE: UntestablePath */
}
return ARES_TRUE;
}
static void ares_evsys_select_destroy(ares_event_thread_t *e)
{
(void)e;
}
static ares_bool_t ares_evsys_select_event_add(ares_event_t *event)
{
(void)event;
return ARES_TRUE;
}
static void ares_evsys_select_event_del(ares_event_t *event)
{
(void)event;
}
static void ares_evsys_select_event_mod(ares_event_t *event,
ares_event_flags_t new_flags)
{
(void)event;
(void)new_flags;
}
static size_t ares_evsys_select_wait(ares_event_thread_t *e,
unsigned long timeout_ms)
{
size_t num_fds = 0;
ares_socket_t *fdlist = ares__htable_asvp_keys(e->ev_sock_handles, &num_fds);
int rv;
size_t cnt = 0;
size_t i;
fd_set read_fds;
fd_set write_fds;
fd_set except_fds;
int nfds = 0;
struct timeval tv;
struct timeval *tout = NULL;
FD_ZERO(&read_fds);
FD_ZERO(&write_fds);
FD_ZERO(&except_fds);
for (i = 0; i < num_fds; i++) {
const ares_event_t *ev =
ares__htable_asvp_get_direct(e->ev_sock_handles, fdlist[i]);
if (ev->flags & ARES_EVENT_FLAG_READ) {
FD_SET(ev->fd, &read_fds);
}
if (ev->flags & ARES_EVENT_FLAG_WRITE) {
FD_SET(ev->fd, &write_fds);
}
FD_SET(ev->fd, &except_fds);
if (ev->fd + 1 > nfds) {
nfds = ev->fd + 1;
}
}
if (timeout_ms) {
tv.tv_sec = (int)(timeout_ms / 1000);
tv.tv_usec = (int)((timeout_ms % 1000) * 1000);
tout = &tv;
}
rv = select(nfds, &read_fds, &write_fds, &except_fds, tout);
if (rv > 0) {
for (i = 0; i < num_fds; i++) {
ares_event_t *ev;
ares_event_flags_t flags = 0;
ev = ares__htable_asvp_get_direct(e->ev_sock_handles, fdlist[i]);
if (ev == NULL || ev->cb == NULL) {
continue; /* LCOV_EXCL_LINE: DefensiveCoding */
}
if (FD_ISSET(fdlist[i], &read_fds) || FD_ISSET(fdlist[i], &except_fds)) {
flags |= ARES_EVENT_FLAG_READ;
}
if (FD_ISSET(fdlist[i], &write_fds)) {
flags |= ARES_EVENT_FLAG_WRITE;
}
if (flags == 0) {
continue;
}
cnt++;
ev->cb(e, fdlist[i], ev->data, flags);
}
}
ares_free(fdlist);
return cnt;
}
const ares_event_sys_t ares_evsys_select = {
"select",
ares_evsys_select_init,
ares_evsys_select_destroy, /* NoOp */
ares_evsys_select_event_add, /* NoOp */
ares_evsys_select_event_del, /* NoOp */
ares_evsys_select_event_mod, /* NoOp */
ares_evsys_select_wait
};
#endif
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