mirror of
https://code.videolan.org/videolan/vlc
synced 2024-09-04 09:11:33 +02:00
![Thomas Guillem](/assets/img/avatar_default.png)
Signed-off-by: Steve Lhomme <robux4@videolabs.io> Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
272 lines
8.1 KiB
C
272 lines
8.1 KiB
C
/*****************************************************************************
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* poll.c: poll() emulation
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*****************************************************************************
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* Copyright © 2007-2012 Rémi Denis-Courmont
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#ifndef _WIN32
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# include <sys/time.h>
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# include <sys/select.h>
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# include <fcntl.h>
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int (poll) (struct pollfd *fds, unsigned nfds, int timeout)
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{
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fd_set rdset[1], wrset[1], exset[1];
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struct timeval tv = { 0, 0 };
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int val = -1;
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FD_ZERO (rdset);
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FD_ZERO (wrset);
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FD_ZERO (exset);
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for (unsigned i = 0; i < nfds; i++)
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{
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int fd = fds[i].fd;
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if (val < fd)
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val = fd;
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/* With POSIX, FD_SET & FD_ISSET are not defined if fd is negative or
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* bigger or equal than FD_SETSIZE. That is one of the reasons why VLC
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* uses poll() rather than select(). Most POSIX systems implement
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* fd_set has a bit field with no sanity checks. This is especially bad
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* on systems (such as BSD) that have no process open files limit by
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* default, such that it is quite feasible to get fd >= FD_SETSIZE.
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* The next instructions will result in a buffer overflow if run on
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* a POSIX system, and the later FD_ISSET would perform an undefined
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* memory read. */
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if ((unsigned)fd >= FD_SETSIZE)
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{
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errno = EINVAL;
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return -1;
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}
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if (fds[i].events & POLLRDNORM)
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FD_SET (fd, rdset);
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if (fds[i].events & POLLWRNORM)
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FD_SET (fd, wrset);
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if (fds[i].events & POLLPRI)
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FD_SET (fd, exset);
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}
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if (timeout >= 0)
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{
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div_t d = div (timeout, 1000);
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tv.tv_sec = d.quot;
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tv.tv_usec = d.rem * 1000;
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}
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val = select (val + 1, rdset, wrset, exset,
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(timeout >= 0) ? &tv : NULL);
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if (val == -1)
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{
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if (errno != EBADF)
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return -1;
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val = 0;
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for (unsigned i = 0; i < nfds; i++)
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if (fcntl (fds[i].fd, F_GETFD) == -1)
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{
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fds[i].revents = POLLNVAL;
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val++;
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}
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else
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fds[i].revents = 0;
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return val ? val : -1;
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}
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for (unsigned i = 0; i < nfds; i++)
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{
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int fd = fds[i].fd;
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fds[i].revents = (FD_ISSET (fd, rdset) ? POLLRDNORM : 0)
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| (FD_ISSET (fd, wrset) ? POLLWRNORM : 0)
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| (FD_ISSET (fd, exset) ? POLLPRI : 0);
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}
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return val;
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}
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#else
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# include <windows.h>
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# include <winsock2.h>
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static int poll_compat(struct pollfd *fds, unsigned nfds, int timeout)
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{
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DWORD to = (timeout >= 0) ? (DWORD)timeout : INFINITE;
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if (nfds == 0)
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{ /* WSAWaitForMultipleEvents() does not allow zero events */
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if (SleepEx(to, TRUE))
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{
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errno = EINTR;
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return -1;
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}
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return 0;
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}
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WSAEVENT *evts = malloc(nfds * sizeof (WSAEVENT));
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if (evts == NULL)
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return -1; /* ENOMEM */
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DWORD ret = WSA_WAIT_FAILED;
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for (unsigned i = 0; i < nfds; i++)
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{
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SOCKET fd = fds[i].fd;
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long mask = FD_CLOSE;
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fd_set rdset, wrset, exset;
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FD_ZERO(&rdset);
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FD_ZERO(&wrset);
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FD_ZERO(&exset);
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FD_SET(fd, &exset);
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if (fds[i].events & POLLRDNORM)
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{
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mask |= FD_READ | FD_ACCEPT;
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FD_SET(fd, &rdset);
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}
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if (fds[i].events & POLLWRNORM)
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{
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mask |= FD_WRITE | FD_CONNECT;
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FD_SET(fd, &wrset);
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}
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if (fds[i].events & POLLPRI)
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mask |= FD_OOB;
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fds[i].revents = 0;
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evts[i] = WSACreateEvent();
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if (evts[i] == WSA_INVALID_EVENT)
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{
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while (i > 0)
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WSACloseEvent(evts[--i]);
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free(evts);
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errno = ENOMEM;
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return -1;
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}
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if (WSAEventSelect(fds[i].fd, evts[i], mask)
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&& WSAGetLastError() == WSAENOTSOCK)
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fds[i].revents |= POLLNVAL;
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struct timeval tv = { 0, 0 };
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/* By its horrible design, WSAEnumNetworkEvents() only enumerates
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* events that were not already signaled (i.e. it is edge-triggered).
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* WSAPoll() would be better in this respect, but worse in others.
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* So use WSAEnumNetworkEvents() after manually checking for pending
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* events. */
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if (select(0, &rdset, &wrset, &exset, &tv) > 0)
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{
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if (FD_ISSET(fd, &rdset))
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fds[i].revents |= fds[i].events & POLLRDNORM;
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if (FD_ISSET(fd, &wrset))
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fds[i].revents |= fds[i].events & POLLWRNORM;
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if (FD_ISSET(fd, &exset))
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/* To add pain to injury, POLLERR and POLLPRI cannot be
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* distinguished here. */
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fds[i].revents |= POLLERR | (fds[i].events & POLLPRI);
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}
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if (fds[i].revents != 0 && ret == WSA_WAIT_FAILED)
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ret = WSA_WAIT_EVENT_0 + i;
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}
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if (ret == WSA_WAIT_FAILED)
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ret = WSAWaitForMultipleEvents(nfds, evts, FALSE, to, TRUE);
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unsigned count = 0;
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for (unsigned i = 0; i < nfds; i++)
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{
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WSANETWORKEVENTS ne;
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if (WSAEnumNetworkEvents(fds[i].fd, evts[i], &ne))
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memset(&ne, 0, sizeof (ne));
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WSAEventSelect(fds[i].fd, evts[i], 0);
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WSACloseEvent(evts[i]);
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if (ne.lNetworkEvents & FD_CONNECT)
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{
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fds[i].revents |= POLLWRNORM;
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if (ne.iErrorCode[FD_CONNECT_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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if (ne.lNetworkEvents & FD_CLOSE)
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{
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fds[i].revents |= (fds[i].events & POLLRDNORM) | POLLHUP;
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if (ne.iErrorCode[FD_CLOSE_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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if (ne.lNetworkEvents & FD_ACCEPT)
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{
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fds[i].revents |= POLLRDNORM;
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if (ne.iErrorCode[FD_ACCEPT_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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if (ne.lNetworkEvents & FD_OOB)
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{
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fds[i].revents |= POLLPRI;
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if (ne.iErrorCode[FD_OOB_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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if (ne.lNetworkEvents & FD_READ)
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{
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fds[i].revents |= POLLRDNORM;
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if (ne.iErrorCode[FD_READ_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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if (ne.lNetworkEvents & FD_WRITE)
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{
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fds[i].revents |= POLLWRNORM;
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if (ne.iErrorCode[FD_WRITE_BIT] != 0)
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fds[i].revents |= POLLERR;
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}
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count += fds[i].revents != 0;
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}
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free(evts);
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if (count == 0 && ret == WSA_WAIT_IO_COMPLETION)
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{
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errno = EINTR;
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return -1;
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}
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return count;
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}
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int poll(struct pollfd *fds, unsigned nfds, int timeout)
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{
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if (timeout == -1)
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{
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/* HACK: In some cases, we lose some events because events are
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* destroyed and recreated only when we need to poll. In order to work
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* arround this issue, we try to call the poll compat function every
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* 100ms (in case of infinite timeout). */
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int ret;
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while ((ret = poll_compat(fds, nfds, 100)) == 0);
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return ret;
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}
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else
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return poll_compat(fds, nfds, timeout);
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}
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#endif
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