Commit acade544 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

Improve Win32 poll replacement (and fix #1949)

parent e2fd6417
/*****************************************************************************
* poll.c: I/O event multiplexing
*****************************************************************************
* Copyright © 2007 Rémi Denis-Courmont
* Copyright © 2007-2008 Rémi Denis-Courmont
* $Id$
*
* Author: Rémi Denis-Courmont
......@@ -28,7 +28,7 @@
#include <vlc_common.h>
#include <vlc_network.h>
#ifdef HAVE_POLL
#ifndef WIN32
struct pollfd;
int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
......@@ -36,73 +36,70 @@ int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
(void)fds; (void)nfds; (void)timeout;
abort ();
}
#else /* !HAVE_POLL */
#else
#include <string.h>
#include <stdlib.h>
#include <vlc_network.h>
int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
{
fd_set rdset, wrset, exset;
struct timeval tv = { 0, 0 };
int val = -1;
WSAEVENT phEvents[nfds];
DWORD val;
FD_ZERO (&rdset);
FD_ZERO (&wrset);
FD_ZERO (&exset);
for (unsigned i = 0; i < nfds; i++)
{
int fd = fds[i].fd;
if (val < fd)
val = fd;
long events = FD_CLOSE;
/* With POSIX, FD_SET & FD_ISSET are not defined if fd is negative or
* bigger or equal than FD_SETSIZE. That is one of the reasons why VLC
* uses poll() rather than select(). Most POSIX systems implement
* fd_set has a bit field with no sanity checks. This is especially bad
* on systems (such as BSD) that have no process open files limit by
* default, such that it is quite feasible to get fd >= FD_SETSIZE.
* The next instructions will result in a buffer overflow if run on
* a POSIX system, and the later FD_ISSET will do undefined memory
* access.
*
* With Winsock, fd_set is a table of integers. This is awfully slow.
* However, FD_SET and FD_ISSET silently and safely discard
* overflows. If it happens we will loose socket events. Note that
* most (if not all) Winsock SOCKET handles are actually bigger than
* FD_SETSIZE in terms of absolute value - they are not POSIX file
* descriptors. From Vista, there is a much nicer WSAPoll(), but Mingw
* is yet to support it.
*
* With BeOS, the situation is unknown (FIXME: document).
*/
if (fds[i].events & POLLIN)
FD_SET (fd, &rdset);
events |= FD_READ | FD_ACCEPT;
if (fds[i].events & POLLOUT)
FD_SET (fd, &wrset);
events |= FD_WRITE;
if (fds[i].events & POLLPRI)
FD_SET (fd, &exset);
events |= FD_OOB;
fds[i].revents = 0;
phEvents[i] = WSACreateEvent ();
WSAEventSelect (fds[i].fd, phEvents[i], events);
}
if (timeout >= 0)
switch (WaitForMultipleObjectsEx (nfds, phEvents, FALSE, timeout, TRUE))
{
div_t d = div (timeout, 1000);
tv.tv_sec = d.quot;
tv.tv_usec = d.rem * 1000;
case WAIT_IO_COMPLETION:
WSASetLastError (WSAEINTR);
return -1;
case WAIT_TIMEOUT:
return 0;
}
val = select (val + 1, &rdset, &wrset, &exset,
(timeout >= 0) ? &tv : NULL);
if (val == -1)
return -1;
int n = 0, err = 0;
for (unsigned i = 0; i < nfds; i++)
{
int fd = fds[i].fd;
fds[i].revents = (FD_ISSET (fd, &rdset) ? POLLIN : 0)
| (FD_ISSET (fd, &wrset) ? POLLOUT : 0)
| (FD_ISSET (fd, &exset) ? POLLPRI : 0);
WSANETWORKEVENTS events;
err = WSAEnumNetworkEvents (fds[i].fd, phEvents[i], &events);
WSACloseEvent (phEvents[i]);
if (err)
{
fds[i].revents |= POLLNVAL;
continue;
}
if (events.lNetworkEvents & FD_CLOSE)
fds[i].revents |= POLLHUP | (fds[i].events & POLLIN);
if (events.lNetworkEvents & FD_ACCEPT)
fds[i].revents |= POLLIN;
if (events.lNetworkEvents & FD_OOB)
fds[i].revents |= POLLPRI;
if (events.lNetworkEvents & FD_READ)
fds[i].revents |= POLLIN;
if (events.lNetworkEvents & FD_WRITE)
{
fds[i].revents |= POLLOUT;
if (events.iErrorCode[FD_WRITE_BIT])
fds[i].revents |= POLLERR;
}
if (fds[i].events)
n++;
}
return val;
return err ? -1 : n;
}
#endif /* !HAVE_POLL */
#endif /* WIN32 */
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