giowin32.c

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/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * giowin32.c: IO Channels for Win32.
 * Copyright 1998 Owen Taylor and Tor Lillqvist
 * Copyright 1999-2000 Tor Lillqvist and Craig Setera
 * Copyright 2001-2003 Andrew Lanoix
 *
 * 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, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * 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/.
 */

/* Define this to get (very) verbose logging of all channels */
/* #define G_IO_WIN32_DEBUG */

/* #include "config.h" */

#include <glib.h>

#include <stdlib.h>
#include <windows.h>
#include <winsock.h>          /* Not everybody has winsock2 */
#include <fcntl.h>
#include <io.h>
#include <process.h>
#include <errno.h>
#include <sys/stat.h>

#include <glib/gstdio.h>

typedef struct _GIOWin32Channel GIOWin32Channel;
typedef struct _GIOWin32Watch GIOWin32Watch;

#define BUFFER_SIZE 4096

typedef enum {
  G_IO_WIN32_WINDOWS_MESSAGES,	/* Windows messages */
  G_IO_WIN32_FILE_DESC,		/* Unix-like file descriptors from
				 * _open() or _pipe(). Read with read().
				 * Have to create separate thread to read.
				 */
  G_IO_WIN32_SOCKET		/* Sockets. A separate thread is blocked
				 * in select() most of the time.
				 */
} GIOWin32ChannelType;

struct _GIOWin32Channel {
  GIOChannel channel;
  gint fd;			/* Either a Unix-like file handle as provided
				 * by the Microsoft C runtime, or a SOCKET
				 * as provided by WinSock.
				 */
  GIOWin32ChannelType type;
  
  gboolean debug;

  CRITICAL_SECTION mutex;

  /* This is used by G_IO_WIN32_WINDOWS_MESSAGES channels */
  HWND hwnd;			/* handle of window, or NULL */
  
  /* Following fields are used by both fd and socket channels. */
  gboolean running;		/* Is reader thread running. FALSE if
				 * EOF has been reached.
				 */
  gboolean needs_close;		/* If the channel has been closed while
				 * the reader thread was still running.
				 */
  guint thread_id;		/* If non-NULL has a reader thread, or has
				 * had.*/
  HANDLE data_avail_event;

  gushort revents;

  /* Following fields used by fd channels for input */
  
  /* Data is kept in a circular buffer. To be able to distinguish between
   * empty and full buffer, we cannot fill it completely, but have to
   * leave a one character gap.
   *
   * Data available is between indexes rdp and wrp-1 (modulo BUFFER_SIZE).
   *
   * Empty:    wrp == rdp
   * Full:     (wrp + 1) % BUFFER_SIZE == rdp
   * Partial:  otherwise
   */
  guchar *buffer;		/* (Circular) buffer */
  gint wrp, rdp;		/* Buffer indices for writing and reading */
  HANDLE space_avail_event;

  /* Following fields used by socket channels */
  GSList *watches;
  HANDLE data_avail_noticed_event;
  gint reset_send; /* socket used to send data so select_thread() can reset/re-loop */
  gint reset_recv; /* socket used to recv data so select_thread() can reset/re-loop */
};

#define LOCK(mutex) EnterCriticalSection (&mutex)
#define UNLOCK(mutex) LeaveCriticalSection (&mutex)

struct _GIOWin32Watch {
  GSource       source;
  GPollFD       pollfd;
  GIOChannel   *channel;
  GIOCondition  condition;
};

static void
g_win32_print_gioflags (GIOFlags flags)
{
  char *bar = "";

  if (flags & G_IO_FLAG_APPEND)
    bar = "|", g_print ("APPEND");
  if (flags & G_IO_FLAG_NONBLOCK)
    g_print ("%sNONBLOCK", bar), bar = "|";
  if (flags & G_IO_FLAG_IS_READABLE)
    g_print ("%sREADABLE", bar), bar = "|";
  if (flags & G_IO_FLAG_IS_WRITEABLE)
    g_print ("%sWRITEABLE", bar), bar = "|";
  if (flags & G_IO_FLAG_IS_SEEKABLE)
    g_print ("%sSEEKABLE", bar), bar = "|";
}

static gboolean
g_io_win32_get_debug_flag (void)
{
#ifdef G_IO_WIN32_DEBUG
  return TRUE;
#else
  if (getenv ("G_IO_WIN32_DEBUG") != NULL)
    return TRUE;
  else
    return FALSE;
#endif
}  

static void
g_io_channel_win32_init (GIOWin32Channel *channel)
{
  channel->debug = g_io_win32_get_debug_flag ();
  channel->buffer = NULL;
  channel->running = FALSE;
  channel->needs_close = FALSE;
  channel->thread_id = 0;
  channel->data_avail_event = NULL;
  channel->revents = 0;
  channel->space_avail_event = NULL;
  channel->reset_send = INVALID_SOCKET;
  channel->reset_recv = INVALID_SOCKET;
  channel->data_avail_noticed_event = NULL;
  channel->watches = NULL;
  InitializeCriticalSection (&channel->mutex);
}

static void
create_events (GIOWin32Channel *channel)
{
  SECURITY_ATTRIBUTES sec_attrs;
  
  sec_attrs.nLength = sizeof (SECURITY_ATTRIBUTES);
  sec_attrs.lpSecurityDescriptor = NULL;
  sec_attrs.bInheritHandle = FALSE;

  /* The data available event is manual reset, the space available event
   * is automatic reset.
   */
  if (!(channel->data_avail_event = CreateEvent (&sec_attrs, TRUE, FALSE, NULL))
      || !(channel->space_avail_event = CreateEvent (&sec_attrs, FALSE, FALSE, NULL))
      || !(channel->data_avail_noticed_event = CreateEvent (&sec_attrs, FALSE, FALSE, NULL)))
    {
      gchar *emsg = g_win32_error_message (GetLastError ());
      g_error ("Error creating event: %s", emsg);
      g_free (emsg);
    }
}

static void
create_thread (GIOWin32Channel     *channel,
	       GIOCondition         condition,
	       unsigned (__stdcall *thread) (void *parameter))
{
  HANDLE thread_handle;

  thread_handle = (HANDLE) _beginthreadex (NULL, 0, thread, channel, 0,
					   &channel->thread_id);
  if (thread_handle == 0)
    g_warning (G_STRLOC ": Error creating reader thread: %s",
	       g_strerror (errno));
  else if (!CloseHandle (thread_handle))
    g_warning (G_STRLOC ": Error closing thread handle: %s\n",
	       g_win32_error_message (GetLastError ()));

  WaitForSingleObject (channel->space_avail_event, INFINITE);
}

static void
init_reset_sockets (GIOWin32Channel *channel)
{
  struct sockaddr_in local, local2, server;
  int len;

  channel->reset_send = (gint) socket (AF_INET, SOCK_DGRAM, 0);
  if (channel->reset_send == INVALID_SOCKET)
    {
      g_warning (G_STRLOC ": Error creating reset_send socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
    }

  local.sin_family = AF_INET;
  local.sin_port = 0;
  local.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  if (bind (channel->reset_send, (struct sockaddr *)&local, sizeof (local)) == SOCKET_ERROR)
    {
      g_warning (G_STRLOC ": Error binding to reset_send socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
  }

  local2.sin_family = AF_INET;
  local2.sin_port = 0;
  local2.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  channel->reset_recv = (gint) socket (AF_INET, SOCK_DGRAM, 0);
  if (channel->reset_recv == INVALID_SOCKET)
    {
      g_warning (G_STRLOC ": Error creating reset_recv socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
  }

  if (bind (channel->reset_recv, (struct sockaddr *)&local2, sizeof (local)) == SOCKET_ERROR)
    {
      g_warning (G_STRLOC ": Error binding to reset_recv socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
    }
  
  len = sizeof (local2);
  if (getsockname (channel->reset_recv, (struct sockaddr *)&local2, &len) == SOCKET_ERROR)
    {
      g_warning (G_STRLOC ": Error getsockname with reset_recv socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
    }

  memset (&server, 0, sizeof (server));
  server.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
  server.sin_family = AF_INET;
  server.sin_port = local2.sin_port;

  if (connect (channel->reset_send, (struct sockaddr  *)&server, sizeof (server)) == SOCKET_ERROR)
    {
      g_warning (G_STRLOC ": connect to reset_recv socket: %s\n",
		 g_win32_error_message (WSAGetLastError ()));
  }

}

static unsigned __stdcall
select_thread (void *parameter)
{
  GIOWin32Channel *channel = parameter;
  fd_set read_fds, write_fds, except_fds;
  GSList *tmp;
  int n;
  char buffer[8];

  g_io_channel_ref ((GIOChannel *)channel);

  if (channel->debug)
    g_print ("select_thread %#x: start fd:%d data_avail:%#x data_avail_noticed:%#x\n",
	     channel->thread_id,
	     channel->fd,
	     (guint) channel->data_avail_event,
	     (guint) channel->data_avail_noticed_event);
  
  channel->rdp = channel->wrp = 0;
  channel->running = TRUE;

  SetEvent (channel->space_avail_event);
  
  while (channel->running)
    {
      FD_ZERO (&read_fds);
      FD_ZERO (&write_fds);
      FD_ZERO (&except_fds);
      FD_SET (channel->reset_recv, &read_fds);

      LOCK (channel->mutex);
      tmp = channel->watches;
      while (tmp)
	{
	  GIOWin32Watch *watch = (GIOWin32Watch *)tmp->data;

	  if (watch->condition & (G_IO_IN | G_IO_HUP))
	    FD_SET (channel->fd, &read_fds);
	  if (watch->condition & G_IO_OUT)
	    FD_SET (channel->fd, &write_fds);
	  if (watch->condition & G_IO_ERR)
	    FD_SET (channel->fd, &except_fds);
	  
	  tmp = tmp->next;
	}
      UNLOCK (channel->mutex);

      if (channel->debug)
	g_print ("select_thread %#x: calling select() for%s%s%s\n",
		 channel->thread_id,
		 (FD_ISSET (channel->fd, &read_fds) ? " IN" : ""),
		 (FD_ISSET (channel->fd, &write_fds) ? " OUT" : ""),
		 (FD_ISSET (channel->fd, &except_fds) ? " ERR" : ""));
      
      n = select (1, &read_fds, &write_fds, &except_fds, NULL);
      
      LOCK (channel->mutex);
      if (channel->needs_close)
	{
	  UNLOCK (channel->mutex);
	  break;
	}
      UNLOCK (channel->mutex);

      if (n == SOCKET_ERROR)
	{
	  if (channel->debug)
	    g_print ("select_thread %#x: select returned SOCKET_ERROR\n",
		     channel->thread_id);
	  break;
	}

    if (FD_ISSET (channel->reset_recv, &read_fds))
    {
      if (channel->debug)
        g_print ("select_thread %#x: re-looping\n",
            channel->thread_id);
      recv (channel->reset_recv,  (char *)&buffer, (int) sizeof (buffer), 0);
      continue;
    }

    if (channel->debug)
      g_print ("select_thread %#x: got%s%s%s\n",
	       channel->thread_id,
	       (FD_ISSET (channel->fd, &read_fds) ? " IN" : ""),
	       (FD_ISSET (channel->fd, &write_fds) ? " OUT" : ""),
	       (FD_ISSET (channel->fd, &except_fds) ? " ERR" : ""));
    
    if (FD_ISSET (channel->fd, &read_fds))
      channel->revents |= G_IO_IN;
    if (FD_ISSET (channel->fd, &write_fds))
      channel->revents |= G_IO_OUT;
    if (FD_ISSET (channel->fd, &except_fds))
      channel->revents |= G_IO_ERR;

    if (channel->debug)
      g_print ("select_thread %#x: resetting data_avail_noticed, setting data_avail\n",
	       channel->thread_id);

    LOCK (channel->mutex);
    ResetEvent (channel->data_avail_noticed_event);
    SetEvent (channel->data_avail_event);
    if (channel->needs_close)
      {
	UNLOCK (channel->mutex);
	break;
      }
    UNLOCK (channel->mutex);

    if (channel->debug)
      g_print ("select_thread %#x: waiting for data_avail_noticed\n",
        channel->thread_id);

    WaitForSingleObject (channel->data_avail_noticed_event, INFINITE);
    if (channel->debug)
      g_print ("select_thread %#x: got data_avail_noticed\n",
		 channel->thread_id);
    }

  LOCK (channel->mutex);
  channel->running = FALSE;
  if (channel->debug)
    g_print ("select_thread %#x: got error, setting data_avail\n",
	     channel->thread_id);
  SetEvent (channel->data_avail_event);
  UNLOCK (channel->mutex);
  g_io_channel_unref ((GIOChannel *)channel);

  /* No need to call _endthreadex(), the actual thread starter routine
   * in MSVCRT (see crt/src/threadex.c:_threadstartex) calls
   * _endthreadex() for us.
   */

  return 0;
}

static gboolean
g_io_win32_prepare (GSource *source,
		    gint    *timeout)
{
  GIOWin32Watch *watch = (GIOWin32Watch *)source;
  GIOCondition buffer_condition = g_io_channel_get_buffer_condition (watch->channel);
  GIOWin32Channel *channel = (GIOWin32Channel *)watch->channel;
  
  *timeout = -1;
  
  if (channel->debug)
    g_print ("g_io_win32_prepare: for thread %#x buffer_condition:%#x\n"
	     "  watch->pollfd.events:%#x watch->pollfd.revents:%#x channel->revents:%#x\n",
	     channel->thread_id, buffer_condition,
	     watch->pollfd.events, watch->pollfd.revents, channel->revents);

  if (channel->type == G_IO_WIN32_FILE_DESC)
    {