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/* Emulation for poll(2)
Contributed by Paolo Bonzini.
Copyright 2001, 2002, 2003, 2006, 2007 Free Software Foundation, Inc.
This file is part of gnulib.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "config.h"
#include <sys/types.h>
#include "poll.h"
#include <errno.h>
#include <limits.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <unistd.h>
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_FILIO_H
#include <sys/filio.h>
#endif
#include <sys/time.h>
#include <time.h>
#ifndef INFTIM
#define INFTIM (-1)
#endif
#ifndef EOVERFLOW
#define EOVERFLOW EINVAL
#endif
int
poll (pfd, nfd, timeout)
struct pollfd *pfd;
nfds_t nfd;
int timeout;
{
fd_set rfds, wfds, efds;
struct timeval tv, *ptv;
int maxfd, rc;
nfds_t i;
#ifdef _SC_OPEN_MAX
if (nfd > sysconf (_SC_OPEN_MAX))
{
errno = EINVAL;
return -1;
}
#else /* !_SC_OPEN_MAX */
#ifdef OPEN_MAX
if (nfd > OPEN_MAX)
{
errno = EINVAL;
return -1;
}
#endif /* OPEN_MAX -- else, no check is needed */
#endif /* !_SC_OPEN_MAX */
/* EFAULT is not necessary to implement, but let's do it in the
simplest case. */
if (!pfd)
{
errno = EFAULT;
return -1;
}
/* convert timeout number into a timeval structure */
ptv = &tv;
if (timeout >= 0)
{
/* return immediately or after timeout */
ptv->tv_sec = timeout / 1000;
ptv->tv_usec = (timeout % 1000) * 1000;
}
else if (timeout == INFTIM)
/* wait forever */
ptv = NULL;
else
{
errno = EINVAL;
return -1;
}
/* create fd sets and determine max fd */
maxfd = -1;
FD_ZERO (&rfds);
FD_ZERO (&wfds);
FD_ZERO (&efds);
for (i = 0; i < nfd; i++)
{
if (pfd[i].fd < 0)
continue;
if (pfd[i].events & (POLLIN | POLLRDNORM))
FD_SET (pfd[i].fd, &rfds);
/* see select(2): "the only exceptional condition detectable
is out-of-band data received on a socket", hence we push
POLLWRBAND events onto wfds instead of efds. */
if (pfd[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND))
FD_SET (pfd[i].fd, &wfds);
if (pfd[i].events & (POLLPRI | POLLRDBAND))
FD_SET (pfd[i].fd, &efds);
if (pfd[i].fd >= maxfd
&& (pfd[i].events & (POLLIN | POLLOUT | POLLPRI
| POLLRDNORM | POLLRDBAND
| POLLWRNORM | POLLWRBAND)))
{
maxfd = pfd[i].fd;
/* Windows use a linear array of sockets (of size FD_SETSIZE). The
descriptor value is not used to address the array. */
#if defined __CYGWIN__ || (!defined _WIN32 && !defined __WIN32__)
if (maxfd > FD_SETSIZE)
{
errno = EOVERFLOW;
return -1;
}
#endif
}
}
/* examine fd sets */
rc = select (maxfd + 1, &rfds, &wfds, &efds, ptv);
if (rc < 0)
return rc;
/* establish results */
rc = 0;
for (i = 0; i < nfd; i++)
if (pfd[i].fd < 0)
pfd[i].revents = 0;
else
{
int happened = 0, sought = pfd[i].events;
if (FD_ISSET (pfd[i].fd, &rfds))
{
int r;
#if defined __MACH__ && defined __APPLE__
/* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
for some kinds of descriptors. Detect if this descriptor is a
connected socket, a server socket, or something else using a
0-byte recv, and use ioctl(2) to detect POLLHUP. */
r = recv (pfd[i].fd, NULL, 0, MSG_PEEK);
if (r == 0 || errno == ENOTSOCK)
ioctl(pfd[i].fd, FIONREAD, &r);
#else
char data[64];
r = recv (pfd[i].fd, data, sizeof (data), MSG_PEEK);
#endif
if (r == 0)
happened |= POLLHUP;
/* If the event happened on an unconnected server socket,
that's fine. */
else if (r > 0 || ( /* (r == -1) && */ errno == ENOTCONN))
happened |= (POLLIN | POLLRDNORM) & sought;
/* Distinguish hung-up sockets from other errors. */
else if (errno == ESHUTDOWN || errno == ECONNRESET
|| errno == ECONNABORTED || errno == ENETRESET)
happened |= POLLHUP;
else
happened |= POLLERR;
}
if (FD_ISSET (pfd[i].fd, &wfds))
happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
if (FD_ISSET (pfd[i].fd, &efds))
happened |= (POLLPRI | POLLRDBAND) & sought;
if (happened)
{
pfd[i].revents = happened;
rc++;
}
}
return rc;
}
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