028aeafabe
Even if the underlying select() reports events, only report those to the caller that were initially requested.
109 lines
2.8 KiB
C++
109 lines
2.8 KiB
C++
/*
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* \brief poll() implementation
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* \author Josef Soentgen
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* \date 2012-07-12
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*
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* this 'poll()' implementation is based on OpenSSHp's and
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* uses our 'select()' function internally.
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*/
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/*
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* Copyright (C) 2010-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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/* Libc includes */
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#include <libc-plugin/plugin_registry.h>
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#include <libc-plugin/plugin.h>
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#include <sys/select.h>
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#include <sys/poll.h>
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#include <stdlib.h>
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using namespace Libc;
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/**
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* The poll function was taken from OpenSSH portable (bsd-poll.c) and adepted
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* to better fit within Genode's libc.
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*
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* Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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extern "C" int
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__attribute__((weak))
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poll(struct pollfd fds[], nfds_t nfds, int timeout)
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{
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nfds_t i;
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int ret, fd, maxfd = 0;
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fd_set readfds, writefds, exceptfds;
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struct timeval tv, *tvp = NULL;
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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if (fd >= (int)FD_SETSIZE) {
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/*errno = EINVAL;*/
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return -1;
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}
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maxfd = MAX(maxfd, fd);
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}
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/* populate event bit vectors for the events we're interested in */
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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if (fd == -1)
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continue;
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if (fds[i].events & POLLIN) {
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FD_SET(fd, &readfds);
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FD_SET(fd, &exceptfds);
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}
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if (fds[i].events & POLLOUT) {
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FD_SET(fd, &writefds);
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FD_SET(fd, &exceptfds);
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}
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}
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/* poll timeout is msec, select is timeval (sec + usec) */
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if (timeout >= 0) {
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tv.tv_sec = timeout / 1000;
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tv.tv_usec = (timeout % 1000) * 1000;
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tvp = &tv;
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}
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ret = select(maxfd + 1, &readfds, &writefds, &exceptfds, tvp);
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/*saved_errno = errno;*/
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/* scan through select results and set poll() flags */
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for (i = 0; i < nfds; i++) {
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fd = fds[i].fd;
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fds[i].revents = 0;
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if (fd == -1)
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continue;
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if ((fds[i].events & POLLIN) && FD_ISSET(fd, &readfds)) {
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fds[i].revents |= POLLIN;
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}
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if ((fds[i].events & POLLOUT) && FD_ISSET(fd, &writefds)) {
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fds[i].revents |= POLLOUT;
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}
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if (FD_ISSET(fd, &exceptfds)) {
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fds[i].revents |= POLLERR;
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}
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}
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/*
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if (ret == -1)
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errno = saved_errno;
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*/
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return ret;
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}
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