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/* poll.cc. Implements poll(2) via usage of select(2) call.
Copyright 2000, 2001, 2002 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#define __INSIDE_CYGWIN_NET__
#define FD_SETSIZE 16384 // lots of fds
#include "winsup.h"
#include <sys/time.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <stdlib.h>
#define USE_SYS_TYPES_FD_SET
#include <winsock2.h>
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygerrno.h"
#include "cygheap.h"
#include "sigproc.h"
extern "C" int
poll (struct pollfd *fds, unsigned int nfds, int timeout)
{
int max_fd = 0;
fd_set *read_fds, *write_fds, *except_fds;
struct timeval tv = { timeout / 1000, (timeout % 1000) * 1000 };
for (unsigned int i = 0; i < nfds; ++i)
if (fds[i].fd > max_fd)
max_fd = fds[i].fd;
size_t fds_size = howmany (max_fd + 1, NFDBITS) * sizeof (fd_mask);
read_fds = (fd_set *) alloca (fds_size);
write_fds = (fd_set *) alloca (fds_size);
except_fds = (fd_set *) alloca (fds_size);
if (!read_fds || !write_fds || !except_fds)
{
set_errno (ENOMEM);
return -1;
}
memset (read_fds, 0, fds_size);
memset (write_fds, 0, fds_size);
memset (except_fds, 0, fds_size);
int invalid_fds = 0;
for (unsigned int i = 0; i < nfds; ++i)
{
fds[i].revents = 0;
if (!cygheap->fdtab.not_open (fds[i].fd))
{
if (fds[i].events & POLLIN)
FD_SET(fds[i].fd, read_fds);
if (fds[i].events & POLLOUT)
FD_SET(fds[i].fd, write_fds);
if (fds[i].events & POLLPRI)
FD_SET(fds[i].fd, except_fds);
}
else if (fds[i].fd >= 0)
{
++invalid_fds;
fds[i].revents = POLLNVAL;
}
}
if (invalid_fds)
return invalid_fds;
int ret = cygwin_select (max_fd + 1, read_fds, write_fds, except_fds, timeout < 0 ? NULL : &tv);
if (ret > 0)
for (unsigned int i = 0; i < nfds; ++i)
{
if (fds[i].fd >= 0)
{
if (cygheap->fdtab.not_open (fds[i].fd))
fds[i].revents = POLLHUP;
else
{
if (FD_ISSET(fds[i].fd, read_fds))
{
char peek[1];
fhandler_socket *sock =
cygheap->fdtab[fds[i].fd]->is_socket ();
if (!sock)
fds[i].revents |= POLLIN;
else
{
/* The following action can change errno. We have to
reset it to it's old value. */
int old_errno = get_errno ();
switch (sock->recvfrom (peek, sizeof (peek), MSG_PEEK,
NULL, NULL))
{
case -1: /* Something weird happened */
/* When select returns that data is available,
that could mean that the socket is in
listen mode and a client tries to connect.
Unfortunately, recvfrom() doesn't make much
sense then. It returns WSAENOTCONN in that
case. Since that's not actually an error,
we must not set POLLERR but POLLIN. */
if (WSAGetLastError () != WSAENOTCONN)
fds[i].revents |= POLLERR;
else
fds[i].revents |= POLLIN;
break;
case 0: /* Closed on the read side. */
fds[i].revents |= POLLHUP;
break;
default:
fds[i].revents |= POLLIN;
break;
}
set_errno (old_errno);
}
}
if (FD_ISSET(fds[i].fd, write_fds))
fds[i].revents |= POLLOUT;
if (FD_ISSET(fds[i].fd, except_fds))
fds[i].revents |= POLLPRI;
}
}
}
return ret;
}
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