/* 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 <glib.h>

#include <glib/gstdio.h>

#include <glib/glib-unix.h>

#include "gioerror.h"

#include "gunixinputstream.h"

#include "gcancellable.h"

#include "gasynchelper.h"

#include "gfiledescriptorbased.h"

#include "glibintl.h"

#include "giounix-private.h"

/**

 * GUnixInputStream:

 *

 * `GUnixInputStream` implements [class@Gio.InputStream] for reading from 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/gunixinputstream.h>` belongs to the UNIX-specific GIO

 * interfaces, thus you have to use the `gio-unix-2.0.pc` pkg-config

 * file or the `GioUnix-2.0` GIR namespace when using it.

 */

enum {

  PROP_0,

  PROP_FD,

  PROP_CLOSE_FD

};

struct _GUnixInputStreamPrivate {

  int fd;

  guint close_fd : 1;

  guint can_poll : 1;

};

static void g_unix_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface);

static void g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface);

G_DEFINE_TYPE_WITH_CODE (GUnixInputStream, g_unix_input_stream, G_TYPE_INPUT_STREAM,

                         G_ADD_PRIVATE (GUnixInputStream)

       G_IMPLEMENT_INTERFACE (G_TYPE_POLLABLE_INPUT_STREAM,

            g_unix_input_stream_pollable_iface_init)

       G_IMPLEMENT_INTERFACE (G_TYPE_FILE_DESCRIPTOR_BASED,

            g_unix_input_stream_file_descriptor_based_iface_init)

       )

static void     g_unix_input_stream_set_property (GObject              *object,

              guint                 prop_id,

              const GValue         *value,

              GParamSpec           *pspec);

static void     g_unix_input_stream_get_property (GObject              *object,

              guint                 prop_id,

              GValue               *value,

              GParamSpec           *pspec);

static gssize   g_unix_input_stream_read         (GInputStream         *stream,

              void                 *buffer,

              gsize                 count,

              GCancellable         *cancellable,

              GError              **error);

static gboolean g_unix_input_stream_close        (GInputStream         *stream,

              GCancellable         *cancellable,

              GError              **error);

static void     g_unix_input_stream_skip_async   (GInputStream         *stream,

              gsize                 count,

              int                   io_priority,

              GCancellable         *cancellable,

              GAsyncReadyCallback   callback,

              gpointer              data);

static gssize   g_unix_input_stream_skip_finish  (GInputStream         *stream,

              GAsyncResult         *result,

              GError              **error);

static gboolean g_unix_input_stream_pollable_can_poll      (GPollableInputStream *stream);

static gboolean g_unix_input_stream_pollable_is_readable   (GPollableInputStream *stream);

static GSource *g_unix_input_stream_pollable_create_source (GPollableInputStream *stream,

                  GCancellable         *cancellable);

static void

g_unix_input_stream_class_init (GUnixInputStreamClass *klass)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);

  gobject_class->get_property = g_unix_input_stream_get_property;

  gobject_class->set_property = g_unix_input_stream_set_property;

  stream_class->read_fn = g_unix_input_stream_read;

  stream_class->close_fn = g_unix_input_stream_close;

  if (0)

    {

      /* TODO: Implement instead of using fallbacks */

      stream_class->skip_async = g_unix_input_stream_skip_async;

      stream_class->skip_finish = g_unix_input_stream_skip_finish;

    }

  /**

   * GUnixInputStream:fd:

   *

   * The file descriptor that the stream reads from.

   *

   * 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));

  /**

   * GUnixInputStream: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_input_stream_pollable_iface_init (GPollableInputStreamInterface *iface)

{

  iface->can_poll = g_unix_input_stream_pollable_can_poll;

  iface->is_readable = g_unix_input_stream_pollable_is_readable;

  iface->create_source = g_unix_input_stream_pollable_create_source;

}

static void

g_unix_input_stream_file_descriptor_based_iface_init (GFileDescriptorBasedIface *iface)

{

  iface->get_fd = (int (*) (GFileDescriptorBased *))g_unix_input_stream_get_fd;

}

static void

g_unix_input_stream_set_property (GObject         *object,

          guint            prop_id,

          const GValue    *value,

          GParamSpec      *pspec)

{

  GUnixInputStream *unix_stream;

  unix_stream = G_UNIX_INPUT_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_input_stream_get_property (GObject    *object,

          guint       prop_id,

          GValue     *value,

          GParamSpec *pspec)

{

  GUnixInputStream *unix_stream;

  unix_stream = G_UNIX_INPUT_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_input_stream_init (GUnixInputStream *unix_stream)

{

  unix_stream->priv = g_unix_input_stream_get_instance_private (unix_stream);

  unix_stream->priv->fd = -1;

  unix_stream->priv->close_fd = TRUE;

}

/**

 * g_unix_input_stream_new:

 * @fd: a UNIX file descriptor

 * @close_fd: %TRUE to close the file descriptor when done

 * 

 * Creates a new #GUnixInputStream for the given @fd. 

 *

 * If @close_fd is %TRUE, the file descriptor will be closed 

 * when the stream is closed.

 * 

 * Returns: a new #GUnixInputStream

 **/

GInputStream *

g_unix_input_stream_new (gint     fd,

       gboolean close_fd)

{

  GUnixInputStream *stream;

  g_return_val_if_fail (fd != -1, NULL);

  stream = g_object_new (G_TYPE_UNIX_INPUT_STREAM,

       "fd", fd,

       "close-fd", close_fd,

       NULL);

  return G_INPUT_STREAM (stream);

}

/**

 * g_unix_input_stream_set_close_fd:

 * @stream: a #GUnixInputStream

 * @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_input_stream_set_close_fd (GUnixInputStream *stream,

          gboolean          close_fd)

{

  g_return_if_fail (G_IS_UNIX_INPUT_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_input_stream_get_close_fd:

 * @stream: a #GUnixInputStream

 *

 * 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_input_stream_get_close_fd (GUnixInputStream *stream)

{

  g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), FALSE);

  return stream->priv->close_fd;

}

/**

 * g_unix_input_stream_get_fd:

 * @stream: a #GUnixInputStream

 *

 * Return the UNIX file descriptor that the stream reads from.

 *

 * Returns: The file descriptor of @stream

 *

 * Since: 2.20

 */

gint

g_unix_input_stream_get_fd (GUnixInputStream *stream)

{

  g_return_val_if_fail (G_IS_UNIX_INPUT_STREAM (stream), -1);

  return stream->priv->fd;

}

static gssize

g_unix_input_stream_read (GInputStream  *stream,

        void          *buffer,

        gsize          count,

        GCancellable  *cancellable,

        GError       **error)

{

  GUnixInputStream *unix_stream;

  gssize res = -1;

  GPollFD poll_fds[2];

  int nfds;

  int poll_ret;

  unix_stream = G_UNIX_INPUT_STREAM (stream);

  poll_fds[0].fd = unix_stream->priv->fd;

  poll_fds[0].events = G_IO_IN;

  if (unix_stream->priv->can_poll &&

      g_cancellable_make_pollfd (cancellable, &poll_fds[1]))

    nfds = 2;

  else

    nfds = 1;

  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 reading from file descriptor: %s"),

           g_strerror (errsv));

    break;

  }

      if (g_cancellable_set_error_if_cancelled (cancellable, error))

  break;

      if (!poll_fds[0].revents)

  continue;

      res = read (unix_stream->priv->fd, buffer, count);

      if (res == -1)

  {

          int errsv = errno;

    if (errsv == EINTR || errsv == EAGAIN)

      continue;

    g_set_error (error, G_IO_ERROR,

           g_io_error_from_errno (errsv),

           _("Error reading from file descriptor: %s"),

           g_strerror (errsv));

  }

      break;

    }

  if (nfds == 2)

    g_cancellable_release_fd (cancellable);

  return res;

}

static gboolean

g_unix_input_stream_close (GInputStream  *stream,

         GCancellable  *cancellable,

         GError       **error)

{

  GUnixInputStream *unix_stream;

  int res;

  unix_stream = G_UNIX_INPUT_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 void

g_unix_input_stream_skip_async (GInputStream        *stream,

        gsize                count,

        int                  io_priority,

        GCancellable        *cancellable,

        GAsyncReadyCallback  callback,

        gpointer             data)

{

  g_warn_if_reached ();

  /* TODO: Not implemented */

}

static gssize

g_unix_input_stream_skip_finish  (GInputStream  *stream,

          GAsyncResult  *result,

          GError       **error)

{

  g_warn_if_reached ();

  return 0;

  /* TODO: Not implemented */

}

static gboolean

g_unix_input_stream_pollable_can_poll (GPollableInputStream *stream)

{

  return G_UNIX_INPUT_STREAM (stream)->priv->can_poll;

}

static gboolean

g_unix_input_stream_pollable_is_readable (GPollableInputStream *stream)

{

  GUnixInputStream *unix_stream = G_UNIX_INPUT_STREAM (stream);

  GPollFD poll_fd;

  gint result;

  poll_fd.fd = unix_stream->priv->fd;

  poll_fd.events = G_IO_IN;

  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_input_stream_pollable_create_source (GPollableInputStream *stream,

              GCancellable         *cancellable)

{

  GUnixInputStream *unix_stream = G_UNIX_INPUT_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_IN);

  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;

}