esp-idf/components/newlib/poll.c

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// Copyright 2019-2020 Espressif Systems (Shanghai) PTE LTD
//
// 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 <stddef.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/errno.h>
#include <sys/param.h>
int poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
struct timeval tv = {
// timeout is in milliseconds
.tv_sec = timeout / 1000,
.tv_usec = (timeout % 1000) * 1000,
};
int max_fd = -1;
fd_set readfds;
fd_set writefds;
fd_set errorfds;
struct _reent* r = __getreent();
int ret = 0;
if (fds == NULL) {
__errno_r(r) = ENOENT;
return -1;
}
FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&errorfds);
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for (unsigned int i = 0; i < nfds; ++i) {
fds[i].revents = 0;
if (fds[i].fd < 0) {
// revents should remain 0 and events ignored (according to the documentation of poll()).
continue;
}
if (fds[i].fd >= FD_SETSIZE) {
fds[i].revents |= POLLNVAL;
++ret;
continue;
}
if (fds[i].events & (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI)) {
FD_SET(fds[i].fd, &readfds);
FD_SET(fds[i].fd, &errorfds);
max_fd = MAX(max_fd, fds[i].fd);
}
if (fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
FD_SET(fds[i].fd, &writefds);
FD_SET(fds[i].fd, &errorfds);
max_fd = MAX(max_fd, fds[i].fd);
}
}
const int select_ret = select(max_fd + 1, &readfds, &writefds, &errorfds, timeout < 0 ? NULL: &tv);
if (select_ret > 0) {
ret += select_ret;
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for (unsigned int i = 0; i < nfds; ++i) {
if (FD_ISSET(fds[i].fd, &readfds)) {
fds[i].revents |= POLLIN;
}
if (FD_ISSET(fds[i].fd, &writefds)) {
fds[i].revents |= POLLOUT;
}
if (FD_ISSET(fds[i].fd, &errorfds)) {
fds[i].revents |= POLLERR;
}
}
} else {
ret = select_ret;
// keeping the errno from select()
}
return ret;
}