gio/gunixoutputstream.c - third_party/glib - Git at Google

 /* GIO - GLib Input, Output and Streaming Library
  *
  * Copyright (C) 2006-2007 Red Hat, Inc.
  *
  * SPDX-License-Identifier: LGPL-2.1-or-later
  *
  * 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 2.1 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/>.
  *
  * Author: Alexander Larsson <alexl@redhat.com>
  */

 #include "config.h"

 #include <unistd.h>
 #include <errno.h>
 #include <stdio.h>
 #include <sys/uio.h>

 #include <glib.h>
 #include <glib/gstdio.h>
 #include <glib/glib-unix.h>
 #include "gioerror.h"
 #include "gunixoutputstream.h"
 #include "gcancellable.h"
 #include "gasynchelper.h"
 #include "gfiledescriptorbased.h"
 #include "glibintl.h"
 #include "gioprivate.h"
 #include "giounix-private.h"


 /**
  * GUnixOutputStream:
  *
  * `GUnixOutputStream` implements [class@Gio.OutputStream] for writing to a UNIX
  * file descriptor, including asynchronous operations. (If the file
  * descriptor refers to a socket or pipe, this will use `poll()` to do
  * asynchronous I/O. If it refers to a regular file, it will fall back
  * to doing asynchronous I/O in another thread.)
  *
  * Note that `<gio/gunixoutputstream.h>` belongs to the UNIX-specific GIO
  * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file
  * file or the `GioUnix-2.0` GIR namespace when using it.
  */

 enum {
   PROP_0,
   PROP_FD,
   PROP_CLOSE_FD
 };

 struct _GUnixOutputStreamPrivate {
   int fd;
   guint close_fd : 1;
   guint can_poll : 1;
 };

 static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
 static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);

 G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
                          G_ADD_PRIVATE (GUnixOutputStream)
 			 G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
 						g_unix_output_stream_pollable_iface_init)
 			 G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
 						g_unix_output_stream_file_descriptor_based_iface_init)
 			 )

 static void     g_unix_output_stream_set_property (GObject              *object,
 						   guint                 prop_id,
 						   const GValue         *value,
 						   GParamSpec           *pspec);
 static void     g_unix_output_stream_get_property (GObject              *object,
 						   guint                 prop_id,
 						   GValue               *value,
 						   GParamSpec           *pspec);
 static gssize   g_unix_output_stream_write        (GOutputStream        *stream,
 						   const void           *buffer,
 						   gsize                 count,
 						   GCancellable         *cancellable,
 						   GError              **error);
 static gboolean g_unix_output_stream_writev       (GOutputStream        *stream,
 						   const GOutputVector  *vectors,
 						   gsize                 n_vectors,
 						   gsize                *bytes_written,
 						   GCancellable         *cancellable,
 						   GError              **error);
 static gboolean g_unix_output_stream_close        (GOutputStream        *stream,
 						   GCancellable         *cancellable,
 						   GError              **error);

 static gboolean g_unix_output_stream_pollable_can_poll      (GPollableOutputStream *stream);
 static gboolean g_unix_output_stream_pollable_is_writable   (GPollableOutputStream *stream);
 static GSource *g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 							     GCancellable         *cancellable);
 static GPollableReturn g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream  *stream,
 									 const GOutputVector    *vectors,
 									 gsize                   n_vectors,
 									 gsize                  *bytes_written,
 									 GError                **error);

 static void
 g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
 {
   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
   GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);

   gobject_class->get_property = g_unix_output_stream_get_property;
   gobject_class->set_property = g_unix_output_stream_set_property;

   stream_class->write_fn = g_unix_output_stream_write;
   stream_class->writev_fn = g_unix_output_stream_writev;
   stream_class->close_fn = g_unix_output_stream_close;

    /**
    * GUnixOutputStream:fd:
    *
    * The file descriptor that the stream writes to.
    *
    * Since: 2.20
    */
   g_object_class_install_property (gobject_class,
 				   PROP_FD,
 				   g_param_spec_int ("fd", NULL, NULL,
 						     G_MININT, G_MAXINT, -1,
 						     G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));

   /**
    * GUnixOutputStream:close-fd:
    *
    * Whether to close the file descriptor when the stream is closed.
    *
    * Since: 2.20
    */
   g_object_class_install_property (gobject_class,
 				   PROP_CLOSE_FD,
 				   g_param_spec_boolean ("close-fd", NULL, NULL,
 							 TRUE,
 							 G_PARAM_READABLE | G_PARAM_WRITABLE | G_PARAM_STATIC_NAME | G_PARAM_STATIC_NICK | G_PARAM_STATIC_BLURB));
 }

 static void
 g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
 {
   iface->can_poll = g_unix_output_stream_pollable_can_poll;
   iface->is_writable = g_unix_output_stream_pollable_is_writable;
   iface->create_source = g_unix_output_stream_pollable_create_source;
   iface->writev_nonblocking = g_unix_output_stream_pollable_writev_nonblocking;
 }

 static void
 g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
 {
   iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_output_stream_get_fd;
 }

 static void
 g_unix_output_stream_set_property (GObject         *object,
 				   guint            prop_id,
 				   const GValue    *value,
 				   GParamSpec      *pspec)
 {
   GUnixOutputStream *unix_stream;

   unix_stream = G_UNIX_OUTPUT_STREAM (object);

   switch (prop_id)
     {
     case PROP_FD:
       unix_stream->priv->fd = g_value_get_int (value);
       unix_stream->priv->can_poll = _g_fd_is_pollable (unix_stream->priv->fd);
       break;
     case PROP_CLOSE_FD:
       unix_stream->priv->close_fd = g_value_get_boolean (value);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
     }
 }

 static void
 g_unix_output_stream_get_property (GObject    *object,
 				   guint       prop_id,
 				   GValue     *value,
 				   GParamSpec *pspec)
 {
   GUnixOutputStream *unix_stream;

   unix_stream = G_UNIX_OUTPUT_STREAM (object);

   switch (prop_id)
     {
     case PROP_FD:
       g_value_set_int (value, unix_stream->priv->fd);
       break;
     case PROP_CLOSE_FD:
       g_value_set_boolean (value, unix_stream->priv->close_fd);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
 }

 static void
 g_unix_output_stream_init (GUnixOutputStream *unix_stream)
 {
   unix_stream->priv = g_unix_output_stream_get_instance_private (unix_stream);
   unix_stream->priv->fd = -1;
   unix_stream->priv->close_fd = TRUE;
 }

 /**
  * g_unix_output_stream_new:
  * @fd: a UNIX file descriptor
  * @close_fd: %TRUE to close the file descriptor when done
  *
  * Creates a new #GUnixOutputStream for the given @fd.
  *
  * If @close_fd, is %TRUE, the file descriptor will be closed when
  * the output stream is destroyed.
  *
  * Returns: a new #GOutputStream
  **/
 GOutputStream *
 g_unix_output_stream_new (gint     fd,
 			  gboolean close_fd)
 {
   GUnixOutputStream *stream;

   g_return_val_if_fail (fd != -1, NULL);

   stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
 			 "fd", fd,
 			 "close-fd", close_fd,
 			 NULL);

   return G_OUTPUT_STREAM (stream);
 }

 /**
  * g_unix_output_stream_set_close_fd:
  * @stream: a #GUnixOutputStream
  * @close_fd: %TRUE to close the file descriptor when done
  *
  * Sets whether the file descriptor of @stream shall be closed
  * when the stream is closed.
  *
  * Since: 2.20
  */
 void
 g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
                                    gboolean           close_fd)
 {
   g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));

   close_fd = close_fd != FALSE;
   if (stream->priv->close_fd != close_fd)
     {
       stream->priv->close_fd = close_fd;
       g_object_notify (G_OBJECT (stream), "close-fd");
     }
 }

 /**
  * g_unix_output_stream_get_close_fd:
  * @stream: a #GUnixOutputStream
  *
  * Returns whether the file descriptor of @stream will be
  * closed when the stream is closed.
  *
  * Returns: %TRUE if the file descriptor is closed when done
  *
  * Since: 2.20
  */
 gboolean
 g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
 {
   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);

   return stream->priv->close_fd;
 }

 /**
  * g_unix_output_stream_get_fd:
  * @stream: a #GUnixOutputStream
  *
  * Return the UNIX file descriptor that the stream writes to.
  *
  * Returns: The file descriptor of @stream
  *
  * Since: 2.20
  */
 gint
 g_unix_output_stream_get_fd (GUnixOutputStream *stream)
 {
   g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);

   return stream->priv->fd;
 }

 static gssize
 g_unix_output_stream_write (GOutputStream  *stream,
 			    const void     *buffer,
 			    gsize           count,
 			    GCancellable   *cancellable,
 			    GError        **error)
 {
   GUnixOutputStream *unix_stream;
   gssize res = -1;
   GPollFD poll_fds[2];
   int nfds = 0;
   int poll_ret;

   unix_stream = G_UNIX_OUTPUT_STREAM (stream);

   poll_fds[0].fd = unix_stream->priv->fd;
   poll_fds[0].events = G_IO_OUT;
   nfds++;

   if (unix_stream->priv->can_poll &&
       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
     nfds++;

   while (1)
     {
       int errsv;

       poll_fds[0].revents = poll_fds[1].revents = 0;
       do
         {
           poll_ret = g_poll (poll_fds, nfds, -1);
           errsv = errno;
         }
       while (poll_ret == -1 && errsv == EINTR);

       if (poll_ret == -1)
 	{
 	  g_set_error (error, G_IO_ERROR,
 		       g_io_error_from_errno (errsv),
 		       _("Error writing to file descriptor: %s"),
 		       g_strerror (errsv));
 	  break;
 	}

       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 	break;

       if (!poll_fds[0].revents)
 	continue;

       res = write (unix_stream->priv->fd, buffer, count);
       errsv = errno;
       if (res == -1)
 	{
 	  if (errsv == EINTR || errsv == EAGAIN)
 	    continue;

 	  g_set_error (error, G_IO_ERROR,
 		       g_io_error_from_errno (errsv),
 		       _("Error writing to file descriptor: %s"),
 		       g_strerror (errsv));
 	}

       break;
     }

   if (nfds == 2)
     g_cancellable_release_fd (cancellable);
   return res;
 }

 /* Macro to check if struct iovec and GOutputVector have the same ABI */
 #define G_OUTPUT_VECTOR_IS_IOVEC (sizeof (struct iovec) == sizeof (GOutputVector) && \
       G_SIZEOF_MEMBER (struct iovec, iov_base) == G_SIZEOF_MEMBER (GOutputVector, buffer) && \
       G_STRUCT_OFFSET (struct iovec, iov_base) == G_STRUCT_OFFSET (GOutputVector, buffer) && \
       G_SIZEOF_MEMBER (struct iovec, iov_len) == G_SIZEOF_MEMBER (GOutputVector, size) && \
       G_STRUCT_OFFSET (struct iovec, iov_len) == G_STRUCT_OFFSET (GOutputVector, size))

 static gboolean
 g_unix_output_stream_writev (GOutputStream        *stream,
 			     const GOutputVector  *vectors,
 			     gsize                 n_vectors,
 			     gsize                *bytes_written,
 			     GCancellable         *cancellable,
 			     GError              **error)
 {
   GUnixOutputStream *unix_stream;
   gssize res = -1;
   GPollFD poll_fds[2];
   int nfds = 0;
   int poll_ret;
   struct iovec *iov;

   if (bytes_written)
     *bytes_written = 0;

   /* Clamp the number of vectors if more given than we can write in one go.
    * The caller has to handle short writes anyway.
    */
   if (n_vectors > G_IOV_MAX)
     n_vectors = G_IOV_MAX;

   unix_stream = G_UNIX_OUTPUT_STREAM (stream);

   if (G_OUTPUT_VECTOR_IS_IOVEC)
     {
       /* ABI is compatible */
       iov = (struct iovec *) vectors;
     }
   else
     {
       gsize i;

       /* ABI is incompatible */
       iov = g_newa (struct iovec, n_vectors);
       for (i = 0; i < n_vectors; i++)
         {
           iov[i].iov_base = (void *)vectors[i].buffer;
           iov[i].iov_len = vectors[i].size;
         }
     }

   poll_fds[0].fd = unix_stream->priv->fd;
   poll_fds[0].events = G_IO_OUT;
   nfds++;

   if (unix_stream->priv->can_poll &&
       g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
     nfds++;

   while (1)
     {
       int errsv;

       poll_fds[0].revents = poll_fds[1].revents = 0;
       do
         {
           poll_ret = g_poll (poll_fds, nfds, -1);
           errsv = errno;
         }
       while (poll_ret == -1 && errsv == EINTR);

       if (poll_ret == -1)
 	{
 	  g_set_error (error, G_IO_ERROR,
 		       g_io_error_from_errno (errsv),
 		       _("Error writing to file descriptor: %s"),
 		       g_strerror (errsv));
 	  break;
 	}

       if (g_cancellable_set_error_if_cancelled (cancellable, error))
 	break;

       if (!poll_fds[0].revents)
 	continue;

       res = writev (unix_stream->priv->fd, iov, n_vectors);
       errsv = errno;
       if (res == -1)
 	{
 	  if (errsv == EINTR || errsv == EAGAIN)
 	    continue;

 	  g_set_error (error, G_IO_ERROR,
 		       g_io_error_from_errno (errsv),
 		       _("Error writing to file descriptor: %s"),
 		       g_strerror (errsv));
 	}

       if (bytes_written)
         *bytes_written = res;

       break;
     }

   if (nfds == 2)
     g_cancellable_release_fd (cancellable);
   return res != -1;
 }

 static gboolean
 g_unix_output_stream_close (GOutputStream  *stream,
 			    GCancellable   *cancellable,
 			    GError        **error)
 {
   GUnixOutputStream *unix_stream;
   int res;

   unix_stream = G_UNIX_OUTPUT_STREAM (stream);

   if (!unix_stream->priv->close_fd)
     return TRUE;

   /* This might block during the close. Doesn't seem to be a way to avoid it though. */
   res = close (unix_stream->priv->fd);
   if (res == -1)
     {
       int errsv = errno;

       g_set_error (error, G_IO_ERROR,
 		   g_io_error_from_errno (errsv),
 		   _("Error closing file descriptor: %s"),
 		   g_strerror (errsv));
     }

   return res != -1;
 }

 static gboolean
 g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
 {
   return G_UNIX_OUTPUT_STREAM (stream)->priv->can_poll;
 }

 static gboolean
 g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
 {
   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
   GPollFD poll_fd;
   gint result;

   poll_fd.fd = unix_stream->priv->fd;
   poll_fd.events = G_IO_OUT;
   poll_fd.revents = 0;

   do
     result = g_poll (&poll_fd, 1, 0);
   while (result == -1 && errno == EINTR);

   return poll_fd.revents != 0;
 }

 static GSource *
 g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
 					     GCancellable          *cancellable)
 {
   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
   GSource *inner_source, *cancellable_source, *pollable_source;

   pollable_source = g_pollable_source_new (G_OBJECT (stream));

   inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_OUT);
   g_source_set_dummy_callback (inner_source);
   g_source_add_child_source (pollable_source, inner_source);
   g_source_unref (inner_source);

   if (cancellable)
     {
       cancellable_source = g_cancellable_source_new (cancellable);
       g_source_set_dummy_callback (cancellable_source);
       g_source_add_child_source (pollable_source, cancellable_source);
       g_source_unref (cancellable_source);
     }

   return pollable_source;
 }

 static GPollableReturn
 g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream  *stream,
 						  const GOutputVector    *vectors,
 						  gsize                   n_vectors,
 						  gsize                  *bytes_written,
 						  GError                **error)
 {
   GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
   struct iovec *iov;
   gssize res = -1;

   if (!g_pollable_output_stream_is_writable (stream))
     {
       *bytes_written = 0;
       return G_POLLABLE_RETURN_WOULD_BLOCK;
     }

   /* Clamp the number of vectors if more given than we can write in one go.
    * The caller has to handle short writes anyway.
    */
   if (n_vectors > G_IOV_MAX)
     n_vectors = G_IOV_MAX;

   if (G_OUTPUT_VECTOR_IS_IOVEC)
     {
       /* ABI is compatible */
       iov = (struct iovec *) vectors;
     }
   else
     {
       gsize i;

       /* ABI is incompatible */
       iov = g_newa (struct iovec, n_vectors);
       for (i = 0; i < n_vectors; i++)
         {
           iov[i].iov_base = (void *)vectors[i].buffer;
           iov[i].iov_len = vectors[i].size;
         }
     }

   while (1)
     {
       int errsv;

       res = writev (unix_stream->priv->fd, iov, n_vectors);
       errsv = errno;
       if (res == -1)
 	{
 	  if (errsv == EINTR)
 	    continue;

 	  g_set_error (error, G_IO_ERROR,
 		       g_io_error_from_errno (errsv),
 		       _("Error writing to file descriptor: %s"),
 		       g_strerror (errsv));
 	}

       if (bytes_written)
         *bytes_written = res;

       break;
     }

   return res != -1 ? G_POLLABLE_RETURN_OK : G_POLLABLE_RETURN_FAILED;
 }
	/* GIO - GLib Input, Output and Streaming Library
	*
	* Copyright (C) 2006-2007 Red Hat, Inc.
	*
	* SPDX-License-Identifier: LGPL-2.1-or-later
	*
	* 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 2.1 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/>.
	*
	* Author: Alexander Larsson <alexl@redhat.com>
	*/

	#include "config.h"

	#include <unistd.h>
	#include <errno.h>
	#include <stdio.h>
	#include <sys/uio.h>

	#include <glib.h>
	#include <glib/gstdio.h>
	#include <glib/glib-unix.h>
	#include "gioerror.h"
	#include "gunixoutputstream.h"
	#include "gcancellable.h"
	#include "gasynchelper.h"
	#include "gfiledescriptorbased.h"
	#include "glibintl.h"
	#include "gioprivate.h"
	#include "giounix-private.h"


	/**
	* GUnixOutputStream:
	*
	* `GUnixOutputStream` implements [class@Gio.OutputStream] for writing to a UNIX
	* file descriptor, including asynchronous operations. (If the file
	* descriptor refers to a socket or pipe, this will use `poll()` to do
	* asynchronous I/O. If it refers to a regular file, it will fall back
	* to doing asynchronous I/O in another thread.)
	*
	* Note that `<gio/gunixoutputstream.h>` belongs to the UNIX-specific GIO
	* interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config file
	* file or the `GioUnix-2.0` GIR namespace when using it.
	*/

	enum {
	PROP_0,
	PROP_FD,
	PROP_CLOSE_FD
	};

	struct _GUnixOutputStreamPrivate {
	int fd;
	guint close_fd : 1;
	guint can_poll : 1;
	};

	static void g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface);
	static void g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);

	G_DEFINE_TYPE_WITH_CODE (GUnixOutputStream, g_unix_output_stream, G_TYPE_OUTPUT_STREAM,
	G_ADD_PRIVATE (GUnixOutputStream)
	G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_OUTPUT_STREAM,
	g_unix_output_stream_pollable_iface_init)
	G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,
	g_unix_output_stream_file_descriptor_based_iface_init)
	)

	static void g_unix_output_stream_set_property (GObject *object,
	guint prop_id,
	const GValue *value,
	GParamSpec *pspec);
	static void g_unix_output_stream_get_property (GObject *object,
	guint prop_id,
	GValue *value,
	GParamSpec *pspec);
	static gssize g_unix_output_stream_write (GOutputStream *stream,
	const void *buffer,
	gsize count,
	GCancellable *cancellable,
	GError **error);
	static gboolean g_unix_output_stream_writev (GOutputStream *stream,
	const GOutputVector *vectors,
	gsize n_vectors,
	gsize *bytes_written,
	GCancellable *cancellable,
	GError **error);
	static gboolean g_unix_output_stream_close (GOutputStream *stream,
	GCancellable *cancellable,
	GError **error);

	static gboolean g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream);
	static gboolean g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream);
	static GSource g_unix_output_stream_pollable_create_source (GPollableOutputStream stream,
	GCancellable *cancellable);
	static GPollableReturn g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
	const GOutputVector *vectors,
	gsize n_vectors,
	gsize *bytes_written,
	GError **error);

	static void
	g_unix_output_stream_class_init (GUnixOutputStreamClass *klass)
	{
	GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
	GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass);

	gobject_class->get_property = g_unix_output_stream_get_property;
	gobject_class->set_property = g_unix_output_stream_set_property;

	stream_class->write_fn = g_unix_output_stream_write;
	stream_class->writev_fn = g_unix_output_stream_writev;
	stream_class->close_fn = g_unix_output_stream_close;

	/**
	* GUnixOutputStream:fd:
	*
	* The file descriptor that the stream writes to.
	*
	* Since: 2.20
	*/
	g_object_class_install_property (gobject_class,
	PROP_FD,
	g_param_spec_int ("fd", NULL, NULL,
	G_MININT, G_MAXINT, -1,
	G_PARAM_READABLE \| G_PARAM_WRITABLE \| G_PARAM_CONSTRUCT_ONLY \| G_PARAM_STATIC_NAME \| G_PARAM_STATIC_NICK \| G_PARAM_STATIC_BLURB));

	/**
	* GUnixOutputStream:close-fd:
	*
	* Whether to close the file descriptor when the stream is closed.
	*
	* Since: 2.20
	*/
	g_object_class_install_property (gobject_class,
	PROP_CLOSE_FD,
	g_param_spec_boolean ("close-fd", NULL, NULL,
	TRUE,
	G_PARAM_READABLE \| G_PARAM_WRITABLE \| G_PARAM_STATIC_NAME \| G_PARAM_STATIC_NICK \| G_PARAM_STATIC_BLURB));
	}

	static void
	g_unix_output_stream_pollable_iface_init (GPollableOutputStreamInterface *iface)
	{
	iface->can_poll = g_unix_output_stream_pollable_can_poll;
	iface->is_writable = g_unix_output_stream_pollable_is_writable;
	iface->create_source = g_unix_output_stream_pollable_create_source;
	iface->writev_nonblocking = g_unix_output_stream_pollable_writev_nonblocking;
	}

	static void
	g_unix_output_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)
	{
	iface->get_fd = (int () (GFileDescriptorBased ))g_unix_output_stream_get_fd;
	}

	static void
	g_unix_output_stream_set_property (GObject *object,
	guint prop_id,
	const GValue *value,
	GParamSpec *pspec)
	{
	GUnixOutputStream *unix_stream;

	unix_stream = G_UNIX_OUTPUT_STREAM (object);

	switch (prop_id)
	{
	case PROP_FD:
	unix_stream->priv->fd = g_value_get_int (value);
	unix_stream->priv->can_poll = _g_fd_is_pollable (unix_stream->priv->fd);
	break;
	case PROP_CLOSE_FD:
	unix_stream->priv->close_fd = g_value_get_boolean (value);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static void
	g_unix_output_stream_get_property (GObject *object,
	guint prop_id,
	GValue *value,
	GParamSpec *pspec)
	{
	GUnixOutputStream *unix_stream;

	unix_stream = G_UNIX_OUTPUT_STREAM (object);

	switch (prop_id)
	{
	case PROP_FD:
	g_value_set_int (value, unix_stream->priv->fd);
	break;
	case PROP_CLOSE_FD:
	g_value_set_boolean (value, unix_stream->priv->close_fd);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	}
	}

	static void
	g_unix_output_stream_init (GUnixOutputStream *unix_stream)
	{
	unix_stream->priv = g_unix_output_stream_get_instance_private (unix_stream);
	unix_stream->priv->fd = -1;
	unix_stream->priv->close_fd = TRUE;
	}

	/**
	* g_unix_output_stream_new:
	* @fd: a UNIX file descriptor
	* @close_fd: %TRUE to close the file descriptor when done
	*
	* Creates a new #GUnixOutputStream for the given @fd.
	*
	* If @close_fd, is %TRUE, the file descriptor will be closed when
	* the output stream is destroyed.
	*
	* Returns: a new #GOutputStream
	**/
	GOutputStream *
	g_unix_output_stream_new (gint fd,
	gboolean close_fd)
	{
	GUnixOutputStream *stream;

	g_return_val_if_fail (fd != -1, NULL);

	stream = g_object_new (G_TYPE_UNIX_OUTPUT_STREAM,
	"fd", fd,
	"close-fd", close_fd,
	NULL);

	return G_OUTPUT_STREAM (stream);
	}

	/**
	* g_unix_output_stream_set_close_fd:
	* @stream: a #GUnixOutputStream
	* @close_fd: %TRUE to close the file descriptor when done
	*
	* Sets whether the file descriptor of @stream shall be closed
	* when the stream is closed.
	*
	* Since: 2.20
	*/
	void
	g_unix_output_stream_set_close_fd (GUnixOutputStream *stream,
	gboolean close_fd)
	{
	g_return_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream));

	close_fd = close_fd != FALSE;
	if (stream->priv->close_fd != close_fd)
	{
	stream->priv->close_fd = close_fd;
	g_object_notify (G_OBJECT (stream), "close-fd");
	}
	}

	/**
	* g_unix_output_stream_get_close_fd:
	* @stream: a #GUnixOutputStream
	*
	* Returns whether the file descriptor of @stream will be
	* closed when the stream is closed.
	*
	* Returns: %TRUE if the file descriptor is closed when done
	*
	* Since: 2.20
	*/
	gboolean
	g_unix_output_stream_get_close_fd (GUnixOutputStream *stream)
	{
	g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), FALSE);

	return stream->priv->close_fd;
	}

	/**
	* g_unix_output_stream_get_fd:
	* @stream: a #GUnixOutputStream
	*
	* Return the UNIX file descriptor that the stream writes to.
	*
	* Returns: The file descriptor of @stream
	*
	* Since: 2.20
	*/
	gint
	g_unix_output_stream_get_fd (GUnixOutputStream *stream)
	{
	g_return_val_if_fail (G_IS_UNIX_OUTPUT_STREAM (stream), -1);

	return stream->priv->fd;
	}

	static gssize
	g_unix_output_stream_write (GOutputStream *stream,
	const void *buffer,
	gsize count,
	GCancellable *cancellable,
	GError **error)
	{
	GUnixOutputStream *unix_stream;
	gssize res = -1;
	GPollFD poll_fds[2];
	int nfds = 0;
	int poll_ret;

	unix_stream = G_UNIX_OUTPUT_STREAM (stream);

	poll_fds[0].fd = unix_stream->priv->fd;
	poll_fds[0].events = G_IO_OUT;
	nfds++;

	if (unix_stream->priv->can_poll &&
	g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
	nfds++;

	while (1)
	{
	int errsv;

	poll_fds[0].revents = poll_fds[1].revents = 0;
	do
	{
	poll_ret = g_poll (poll_fds, nfds, -1);
	errsv = errno;
	}
	while (poll_ret == -1 && errsv == EINTR);

	if (poll_ret == -1)
	{
	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error writing to file descriptor: %s"),
	g_strerror (errsv));
	break;
	}

	if (g_cancellable_set_error_if_cancelled (cancellable, error))
	break;

	if (!poll_fds[0].revents)
	continue;

	res = write (unix_stream->priv->fd, buffer, count);
	errsv = errno;
	if (res == -1)
	{
	if (errsv == EINTR \|\| errsv == EAGAIN)
	continue;

	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error writing to file descriptor: %s"),
	g_strerror (errsv));
	}

	break;
	}

	if (nfds == 2)
	g_cancellable_release_fd (cancellable);
	return res;
	}

	/* Macro to check if struct iovec and GOutputVector have the same ABI */
	#define G_OUTPUT_VECTOR_IS_IOVEC (sizeof (struct iovec) == sizeof (GOutputVector) && \
	G_SIZEOF_MEMBER (struct iovec, iov_base) == G_SIZEOF_MEMBER (GOutputVector, buffer) && \
	G_STRUCT_OFFSET (struct iovec, iov_base) == G_STRUCT_OFFSET (GOutputVector, buffer) && \
	G_SIZEOF_MEMBER (struct iovec, iov_len) == G_SIZEOF_MEMBER (GOutputVector, size) && \
	G_STRUCT_OFFSET (struct iovec, iov_len) == G_STRUCT_OFFSET (GOutputVector, size))

	static gboolean
	g_unix_output_stream_writev (GOutputStream *stream,
	const GOutputVector *vectors,
	gsize n_vectors,
	gsize *bytes_written,
	GCancellable *cancellable,
	GError **error)
	{
	GUnixOutputStream *unix_stream;
	gssize res = -1;
	GPollFD poll_fds[2];
	int nfds = 0;
	int poll_ret;
	struct iovec *iov;

	if (bytes_written)
	*bytes_written = 0;

	/* Clamp the number of vectors if more given than we can write in one go.
	* The caller has to handle short writes anyway.
	*/
	if (n_vectors > G_IOV_MAX)
	n_vectors = G_IOV_MAX;

	unix_stream = G_UNIX_OUTPUT_STREAM (stream);

	if (G_OUTPUT_VECTOR_IS_IOVEC)
	{
	/* ABI is compatible */
	iov = (struct iovec *) vectors;
	}
	else
	{
	gsize i;

	/* ABI is incompatible */
	iov = g_newa (struct iovec, n_vectors);
	for (i = 0; i < n_vectors; i++)
	{
	iov[i].iov_base = (void *)vectors[i].buffer;
	iov[i].iov_len = vectors[i].size;
	}
	}

	poll_fds[0].fd = unix_stream->priv->fd;
	poll_fds[0].events = G_IO_OUT;
	nfds++;

	if (unix_stream->priv->can_poll &&
	g_cancellable_make_pollfd (cancellable, &poll_fds[1]))
	nfds++;

	while (1)
	{
	int errsv;

	poll_fds[0].revents = poll_fds[1].revents = 0;
	do
	{
	poll_ret = g_poll (poll_fds, nfds, -1);
	errsv = errno;
	}
	while (poll_ret == -1 && errsv == EINTR);

	if (poll_ret == -1)
	{
	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error writing to file descriptor: %s"),
	g_strerror (errsv));
	break;
	}

	if (g_cancellable_set_error_if_cancelled (cancellable, error))
	break;

	if (!poll_fds[0].revents)
	continue;

	res = writev (unix_stream->priv->fd, iov, n_vectors);
	errsv = errno;
	if (res == -1)
	{
	if (errsv == EINTR \|\| errsv == EAGAIN)
	continue;

	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error writing to file descriptor: %s"),
	g_strerror (errsv));
	}

	if (bytes_written)
	*bytes_written = res;

	break;
	}

	if (nfds == 2)
	g_cancellable_release_fd (cancellable);
	return res != -1;
	}

	static gboolean
	g_unix_output_stream_close (GOutputStream *stream,
	GCancellable *cancellable,
	GError **error)
	{
	GUnixOutputStream *unix_stream;
	int res;

	unix_stream = G_UNIX_OUTPUT_STREAM (stream);

	if (!unix_stream->priv->close_fd)
	return TRUE;

	/* This might block during the close. Doesn't seem to be a way to avoid it though. */
	res = close (unix_stream->priv->fd);
	if (res == -1)
	{
	int errsv = errno;

	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error closing file descriptor: %s"),
	g_strerror (errsv));
	}

	return res != -1;
	}

	static gboolean
	g_unix_output_stream_pollable_can_poll (GPollableOutputStream *stream)
	{
	return G_UNIX_OUTPUT_STREAM (stream)->priv->can_poll;
	}

	static gboolean
	g_unix_output_stream_pollable_is_writable (GPollableOutputStream *stream)
	{
	GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
	GPollFD poll_fd;
	gint result;

	poll_fd.fd = unix_stream->priv->fd;
	poll_fd.events = G_IO_OUT;
	poll_fd.revents = 0;

	do
	result = g_poll (&poll_fd, 1, 0);
	while (result == -1 && errno == EINTR);

	return poll_fd.revents != 0;
	}

	static GSource *
	g_unix_output_stream_pollable_create_source (GPollableOutputStream *stream,
	GCancellable *cancellable)
	{
	GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
	GSource inner_source, cancellable_source, *pollable_source;

	pollable_source = g_pollable_source_new (G_OBJECT (stream));

	inner_source = g_unix_fd_source_new (unix_stream->priv->fd, G_IO_OUT);
	g_source_set_dummy_callback (inner_source);
	g_source_add_child_source (pollable_source, inner_source);
	g_source_unref (inner_source);

	if (cancellable)
	{
	cancellable_source = g_cancellable_source_new (cancellable);
	g_source_set_dummy_callback (cancellable_source);
	g_source_add_child_source (pollable_source, cancellable_source);
	g_source_unref (cancellable_source);
	}

	return pollable_source;
	}

	static GPollableReturn
	g_unix_output_stream_pollable_writev_nonblocking (GPollableOutputStream *stream,
	const GOutputVector *vectors,
	gsize n_vectors,
	gsize *bytes_written,
	GError **error)
	{
	GUnixOutputStream *unix_stream = G_UNIX_OUTPUT_STREAM (stream);
	struct iovec *iov;
	gssize res = -1;

	if (!g_pollable_output_stream_is_writable (stream))
	{
	*bytes_written = 0;
	return G_POLLABLE_RETURN_WOULD_BLOCK;
	}

	/* Clamp the number of vectors if more given than we can write in one go.
	* The caller has to handle short writes anyway.
	*/
	if (n_vectors > G_IOV_MAX)
	n_vectors = G_IOV_MAX;

	if (G_OUTPUT_VECTOR_IS_IOVEC)
	{
	/* ABI is compatible */
	iov = (struct iovec *) vectors;
	}
	else
	{
	gsize i;

	/* ABI is incompatible */
	iov = g_newa (struct iovec, n_vectors);
	for (i = 0; i < n_vectors; i++)
	{
	iov[i].iov_base = (void *)vectors[i].buffer;
	iov[i].iov_len = vectors[i].size;
	}
	}

	while (1)
	{
	int errsv;

	res = writev (unix_stream->priv->fd, iov, n_vectors);
	errsv = errno;
	if (res == -1)
	{
	if (errsv == EINTR)
	continue;

	g_set_error (error, G_IO_ERROR,
	g_io_error_from_errno (errsv),
	_("Error writing to file descriptor: %s"),
	g_strerror (errsv));
	}

	if (bytes_written)
	*bytes_written = res;

	break;
	}

	return res != -1 ? G_POLLABLE_RETURN_OK : G_POLLABLE_RETURN_FAILED;
	}