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/*
* Copyright (C) 2015-2020 "IoT.bzh"
* Author José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <unistd.h>
#include <sys/epoll.h>
#define FDEV_PROVIDER
#include "fdev.h"
#include "fdev-epoll.h"
/*
* For sake of simplicity there is no struct fdev_epoll.
* Instead, the file descriptor of the internal epoll is used
* and wrapped in a pseudo pointer to a pseudo struct.
*/
#define epollfd(fdev_epoll) ((int)(intptr_t)fdev_epoll)
/*
* disable callback for fdev
*
* refs to fdev must not be counted here
*/
static void disable(void *closure, const struct fdev *fdev)
{
struct fdev_epoll *fdev_epoll = closure;
epoll_ctl(epollfd(fdev_epoll), EPOLL_CTL_DEL, fdev_fd(fdev), 0);
}
/*
* enable callback for fdev
*
* refs to fdev must not be counted here
*/
static void enable_or_update(void *closure, const struct fdev *fdev, int op, int err)
{
struct fdev_epoll *fdev_epoll = closure;
struct epoll_event event;
int rc, fd;
fd = fdev_fd(fdev);
event.events = fdev_events(fdev);
event.data.ptr = (void*)fdev;
rc = epoll_ctl(epollfd(fdev_epoll), op, fd, &event);
if (rc < 0 && errno == err)
epoll_ctl(epollfd(fdev_epoll), (EPOLL_CTL_MOD + EPOLL_CTL_ADD) - op, fd, &event);
}
/*
* enable callback for fdev
*
* refs to fdev must not be counted here
*/
static void enable(void *closure, const struct fdev *fdev)
{
enable_or_update(closure, fdev, EPOLL_CTL_ADD, EEXIST);
}
/*
* update callback for fdev
*
* refs to fdev must not be counted here
*/
static void update(void *closure, const struct fdev *fdev)
{
enable_or_update(closure, fdev, EPOLL_CTL_MOD, ENOENT);
}
/*
* unref is not handled here
*/
static struct fdev_itf itf =
{
.unref = 0,
.disable = disable,
.enable = enable,
.update = update
};
/*
* create an fdev_epoll
*/
struct fdev_epoll *fdev_epoll_create()
{
int fd = epoll_create1(EPOLL_CLOEXEC);
if (!fd) {
fd = dup(fd);
close(0);
}
return fd < 0 ? 0 : (struct fdev_epoll*)(intptr_t)fd;
}
/*
* destroy the fdev_epoll
*/
void fdev_epoll_destroy(struct fdev_epoll *fdev_epoll)
{
close(epollfd(fdev_epoll));
}
/*
* get pollable fd for the fdev_epoll
*/
int fdev_epoll_fd(struct fdev_epoll *fdev_epoll)
{
return epollfd(fdev_epoll);
}
/*
* create an fdev linked to the 'fdev_epoll' for 'fd'
*/
struct fdev *fdev_epoll_add(struct fdev_epoll *fdev_epoll, int fd)
{
struct fdev *fdev;
fdev = fdev_create(fd);
if (fdev)
fdev_set_itf(fdev, &itf, fdev_epoll);
return fdev;
}
/*
* get pollable fd for the fdev_epoll
*/
int fdev_epoll_wait_and_dispatch(struct fdev_epoll *fdev_epoll, int timeout_ms)
{
struct fdev *fdev;
struct epoll_event events;
int rc;
rc = epoll_wait(epollfd(fdev_epoll), &events, 1, timeout_ms < 0 ? -1 : timeout_ms);
if (rc == 1) {
fdev = events.data.ptr;
fdev_dispatch(fdev, events.events);
}
return rc;
}
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