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/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* gpoll.c: poll(2) abstraction
* Copyright 1998 Owen Taylor
* Copyright 2008 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
/*
* MT safe
*/
#include "config.h"
#include "glibconfig.h"
#include "giochannel.h"
/* Uncomment the next line (and the corresponding line in gmain.c) to
* enable debugging printouts if the environment variable
* G_MAIN_POLL_DEBUG is set to some value.
*/
/* #define G_MAIN_POLL_DEBUG */
#ifdef _WIN32
/* Always enable debugging printout on Windows, as it is more often
* needed there...
*/
#define G_MAIN_POLL_DEBUG
#endif
#include <sys/types.h>
#include <time.h>
#include <stdlib.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif /* HAVE_SYS_TIME_H */
#ifdef HAVE_POLL
# include <poll.h>
/* The poll() emulation on OS/X doesn't handle fds=NULL, nfds=0,
* so we prefer our own poll emulation.
*/
#if defined(_POLL_EMUL_H_) || defined(BROKEN_POLL)
#undef HAVE_POLL
#endif
#endif /* GLIB_HAVE_SYS_POLL_H */
#ifdef G_OS_UNIX
#include <unistd.h>
#endif /* G_OS_UNIX */
#include <errno.h>
#ifdef G_OS_WIN32
#define STRICT
#include <windows.h>
#endif /* G_OS_WIN32 */
#include "gpoll.h"
#ifdef G_OS_WIN32
#include "gprintf.h"
#endif
#ifdef G_MAIN_POLL_DEBUG
extern gboolean _g_main_poll_debug;
#endif
#ifdef HAVE_POLL
/**
* g_poll:
* @fds: file descriptors to poll
* @nfds: the number of file descriptors in @fds
* @timeout: amount of time to wait, in milliseconds, or -1 to wait forever
*
* Polls @fds, as with the poll() system call, but portably. (On
* systems that don't have poll(), it is emulated using select().)
* This is used internally by #GMainContext, but it can be called
* directly if you need to block until a file descriptor is ready, but
* don't want to run the full main loop.
*
* Each element of @fds is a #GPollFD describing a single file
* descriptor to poll. The %fd field indicates the file descriptor,
* and the %events field indicates the events to poll for. On return,
* the %revents fields will be filled with the events that actually
* occurred.
*
* On POSIX systems, the file descriptors in @fds can be any sort of
* file descriptor, but the situation is much more complicated on
* Windows. If you need to use g_poll() in code that has to run on
* Windows, the easiest solution is to construct all of your
* #GPollFDs with g_io_channel_win32_make_pollfd().
*
* Returns: the number of entries in @fds whose %revents fields
* were filled in, or 0 if the operation timed out, or -1 on error or
* if the call was interrupted.
*
* Since: 2.20
**/
gint
g_poll (GPollFD *fds,
guint nfds,
gint timeout)
{
return poll ((struct pollfd *)fds, nfds, timeout);
}
#else /* !HAVE_POLL */
#ifdef G_OS_WIN32
static int
poll_rest (gboolean poll_msgs,
HANDLE *handles,
gint nhandles,
GPollFD *fds,
guint nfds,
gint timeout)
{
DWORD ready;
GPollFD *f;
int recursed_result;
if (poll_msgs)
{
/* Wait for either messages or handles
* -> Use MsgWaitForMultipleObjectsEx
*/
if (_g_main_poll_debug)
g_print (" MsgWaitForMultipleObjectsEx(%d, %d)\n", nhandles, timeout);
ready = MsgWaitForMultipleObjectsEx (nhandles, handles, timeout,
QS_ALLINPUT, MWMO_ALERTABLE);
if (ready == WAIT_FAILED)
{
gchar *emsg = g_win32_error_message (GetLastError ());
g_warning ("MsgWaitForMultipleObjectsEx failed: %s", emsg);
g_free (emsg);
}
}
else if (nhandles == 0)
{
/* No handles to wait for, just the timeout */
if (timeout == INFINITE)
ready = WAIT_FAILED;
else
{
SleepEx (timeout, TRUE);
ready = WAIT_TIMEOUT;
}
}
else
{
/* Wait for just handles
* -> Use WaitForMultipleObjectsEx
*/
if (_g_main_poll_debug)
g_print (" WaitForMultipleObjectsEx(%d, %d)\n", nhandles, timeout);
ready = WaitForMultipleObjectsEx (nhandles, handles, FALSE, timeout, TRUE);
if (ready == WAIT_FAILED)
{
gchar *emsg = g_win32_error_message (GetLastError ());
g_warning ("WaitForMultipleObjectsEx failed: %s", emsg);
g_free (emsg);
}
}
if (_g_main_poll_debug)
g_print (" wait returns %ld%s\n",
ready,
(ready == WAIT_FAILED ? " (WAIT_FAILED)" :
(ready == WAIT_TIMEOUT ? " (WAIT_TIMEOUT)" :
(poll_msgs && ready == WAIT_OBJECT_0 + nhandles ? " (msg)" : ""))));
if (ready == WAIT_FAILED)
return -1;
else if (ready == WAIT_TIMEOUT ||
ready == WAIT_IO_COMPLETION)
return 0;
else if (poll_msgs && ready == WAIT_OBJECT_0 + nhandles)
{
for (f = fds; f < &fds[nfds]; ++f)
if (f->fd == G_WIN32_MSG_HANDLE && f->events & G_IO_IN)
f->revents |= G_IO_IN;
/* If we have a timeout, or no handles to poll, be satisfied
* with just noticing we have messages waiting.
*/
if (timeout != 0 || nhandles == 0)
return 1;
/* If no timeout and handles to poll, recurse to poll them,
* too.
*/
recursed_result = poll_rest (FALSE, handles, nhandles, fds, nfds, 0);
return (recursed_result == -1) ? -1 : 1 + recursed_result;
}
else if (ready >= WAIT_OBJECT_0 && ready < WAIT_OBJECT_0 + nhandles)
{
for (f = fds; f < &fds[nfds]; ++f)
{
if ((HANDLE) f->fd == handles[ready - WAIT_OBJECT_0])
{
f->revents = f->events;
if (_g_main_poll_debug)
g_print (" got event %p\n", (HANDLE) f->fd);
}
}
/* If no timeout and polling several handles, recurse to poll
* the rest of them.
*/
if (timeout == 0 && nhandles > 1)
{
/* Remove the handle that fired */
int i;
if (ready < nhandles - 1)
for (i = ready - WAIT_OBJECT_0 + 1; i < nhandles; i++)
handles[i-1] = handles[i];
nhandles--;
recursed_result = poll_rest (FALSE, handles, nhandles, fds, nfds, 0);
return (recursed_result == -1) ? -1 : 1 + recursed_result;
}
return 1;
}
return 0;
}
gint
g_poll (GPollFD *fds,
guint nfds,
gint timeout)
{
HANDLE handles[MAXIMUM_WAIT_OBJECTS];
gboolean poll_msgs = FALSE;
GPollFD *f;
gint nhandles = 0;
int retval;
if (_g_main_poll_debug)
g_print ("g_poll: waiting for");
for (f = fds; f < &fds[nfds]; ++f)
if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN))
{
if (_g_main_poll_debug && !poll_msgs)
g_print (" MSG");
poll_msgs = TRUE;
}
else if (f->fd > 0)
{
if (nhandles == MAXIMUM_WAIT_OBJECTS)
{
g_warning ("Too many handles to wait for!\n");
break;
}
else
{
if (_g_main_poll_debug)
g_print (" %p", (HANDLE) f->fd);
handles[nhandles++] = (HANDLE) f->fd;
}
}
if (_g_main_poll_debug)
g_print ("\n");
for (f = fds; f < &fds[nfds]; ++f)
f->revents = 0;
if (timeout == -1)
timeout = INFINITE;
/* Polling for several things? */
if (nhandles > 1 || (nhandles > 0 && poll_msgs))
{
/* First check if one or several of them are immediately
* available
*/
retval = poll_rest (poll_msgs, handles, nhandles, fds, nfds, 0);
/* If not, and we have a significant timeout, poll again with
* timeout then. Note that this will return indication for only
* one event, or only for messages. We ignore timeouts less than
* ten milliseconds as they are mostly pointless on Windows, the
* MsgWaitForMultipleObjectsEx() call will timeout right away
* anyway.
*/
if (retval == 0 && (timeout == INFINITE || timeout >= 10))
retval = poll_rest (poll_msgs, handles, nhandles, fds, nfds, timeout);
}
else
{
/* Just polling for one thing, so no need to check first if
* available immediately
*/
retval = poll_rest (poll_msgs, handles, nhandles, fds, nfds, timeout);
}
if (retval == -1)
for (f = fds; f < &fds[nfds]; ++f)
f->revents = 0;
return retval;
}
#else /* !G_OS_WIN32 */
/* The following implementation of poll() comes from the GNU C Library.
* Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
*/
#include <string.h> /* for bzero on BSD systems */
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */
#ifndef NO_FD_SET
# define SELECT_MASK fd_set
#else /* !NO_FD_SET */
# ifndef _AIX
typedef long fd_mask;
# endif /* _AIX */
# ifdef _IBMR2
# define SELECT_MASK void
# else /* !_IBMR2 */
# define SELECT_MASK int
# endif /* !_IBMR2 */
#endif /* !NO_FD_SET */
gint
g_poll (GPollFD *fds,
guint nfds,
gint timeout)
{
struct timeval tv;
SELECT_MASK rset, wset, xset;
GPollFD *f;
int ready;
int maxfd = 0;
FD_ZERO (&rset);
FD_ZERO (&wset);
FD_ZERO (&xset);
for (f = fds; f < &fds[nfds]; ++f)
if (f->fd >= 0)
{
if (f->events & G_IO_IN)
FD_SET (f->fd, &rset);
if (f->events & G_IO_OUT)
FD_SET (f->fd, &wset);
if (f->events & G_IO_PRI)
FD_SET (f->fd, &xset);
if (f->fd > maxfd && (f->events & (G_IO_IN|G_IO_OUT|G_IO_PRI)))
maxfd = f->fd;
}
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
ready = select (maxfd + 1, &rset, &wset, &xset,
timeout == -1 ? NULL : &tv);
if (ready > 0)
for (f = fds; f < &fds[nfds]; ++f)
{
f->revents = 0;
if (f->fd >= 0)
{
if (FD_ISSET (f->fd, &rset))
f->revents |= G_IO_IN;
if (FD_ISSET (f->fd, &wset))
f->revents |= G_IO_OUT;
if (FD_ISSET (f->fd, &xset))
f->revents |= G_IO_PRI;
}
}
return ready;
}
#endif /* !G_OS_WIN32 */
#endif /* !HAVE_POLL */