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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright © 2009 Codethink Limited
*
* This program 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 licence or (at
* your option) any later version.
*
* See the included COPYING file for more information.
*
* Authors: Ryan Lortie <desrt@desrt.ca>
*/
/**
* SECTION:gsocketcontrolmessage
* @title: GSocketControlMessage
* @short_description: A GSocket control message
* @include: gio/gio.h
* @see_also: #GSocket.
*
* A #GSocketControlMessage is a special-purpose utility message that
* can be sent to or received from a #GSocket. These types of
* messages are often called "ancillary data".
*
* The message can represent some sort of special instruction to or
* information from the socket or can represent a special kind of
* transfer to the peer (for example, sending a file descriptor over
* a UNIX socket).
*
* These messages are sent with g_socket_send_message() and received
* with g_socket_receive_message().
*
* To extend the set of control message that can be sent, subclass this
* class and override the get_size, get_level, get_type and serialize
* methods.
*
* To extend the set of control messages that can be received, subclass
* this class and implement the deserialize method. Also, make sure your
* class is registered with the GType typesystem before calling
* g_socket_receive_message() to read such a message.
*
* Since: 2.22
*/
#include "config.h"
#include "gsocketcontrolmessage.h"
#include "gnetworkingprivate.h"
#include "glibintl.h"
#ifndef G_OS_WIN32
#include "gunixcredentialsmessage.h"
#include "gunixfdmessage.h"
#endif
G_DEFINE_ABSTRACT_TYPE (GSocketControlMessage,
g_socket_control_message,
G_TYPE_OBJECT);
/**
* g_socket_control_message_get_size:
* @message: a #GSocketControlMessage
*
* Returns the space required for the control message, not including
* headers or alignment.
*
* Returns: The number of bytes required.
*
* Since: 2.22
*/
gsize
g_socket_control_message_get_size (GSocketControlMessage *message)
{
g_return_val_if_fail (G_IS_SOCKET_CONTROL_MESSAGE (message), 0);
return G_SOCKET_CONTROL_MESSAGE_GET_CLASS (message)->get_size (message);
}
/**
* g_socket_control_message_get_level:
* @message: a #GSocketControlMessage
*
* Returns the "level" (i.e. the originating protocol) of the control message.
* This is often SOL_SOCKET.
*
* Returns: an integer describing the level
*
* Since: 2.22
*/
int
g_socket_control_message_get_level (GSocketControlMessage *message)
{
g_return_val_if_fail (G_IS_SOCKET_CONTROL_MESSAGE (message), 0);
return G_SOCKET_CONTROL_MESSAGE_GET_CLASS (message)->get_level (message);
}
/**
* g_socket_control_message_get_msg_type:
* @message: a #GSocketControlMessage
*
* Returns the protocol specific type of the control message.
* For instance, for UNIX fd passing this would be SCM_RIGHTS.
*
* Returns: an integer describing the type of control message
*
* Since: 2.22
*/
int
g_socket_control_message_get_msg_type (GSocketControlMessage *message)
{
g_return_val_if_fail (G_IS_SOCKET_CONTROL_MESSAGE (message), 0);
return G_SOCKET_CONTROL_MESSAGE_GET_CLASS (message)->get_type (message);
}
/**
* g_socket_control_message_serialize:
* @message: a #GSocketControlMessage
* @data: A buffer to write data to
*
* Converts the data in the message to bytes placed in the
* message.
*
* @data is guaranteed to have enough space to fit the size
* returned by g_socket_control_message_get_size() on this
* object.
*
* Since: 2.22
*/
void
g_socket_control_message_serialize (GSocketControlMessage *message,
gpointer data)
{
g_return_if_fail (G_IS_SOCKET_CONTROL_MESSAGE (message));
G_SOCKET_CONTROL_MESSAGE_GET_CLASS (message)->serialize (message, data);
}
static void
g_socket_control_message_init (GSocketControlMessage *message)
{
}
static void
g_socket_control_message_class_init (GSocketControlMessageClass *class)
{
}
/**
* g_socket_control_message_deserialize:
* @level: a socket level
* @type: a socket control message type for the given @level
* @size: the size of the data in bytes
* @data: (array length=size) (element-type guint8): pointer to the message data
*
* Tries to deserialize a socket control message of a given
* @level and @type. This will ask all known (to GType) subclasses
* of #GSocketControlMessage if they can understand this kind
* of message and if so deserialize it into a #GSocketControlMessage.
*
* If there is no implementation for this kind of control message, %NULL
* will be returned.
*
* Returns: (transfer full): the deserialized message or %NULL
*
* Since: 2.22
*/
GSocketControlMessage *
g_socket_control_message_deserialize (int level,
int type,
gsize size,
gpointer data)
{
GSocketControlMessage *message;
GType *message_types;
guint n_message_types;
int i;
/* Ensure we know about the built in types */
#ifndef G_OS_WIN32
g_type_ensure (G_TYPE_UNIX_CREDENTIALS_MESSAGE);
g_type_ensure (G_TYPE_UNIX_FD_MESSAGE);
#endif
message_types = g_type_children (G_TYPE_SOCKET_CONTROL_MESSAGE, &n_message_types);
message = NULL;
for (i = 0; i < n_message_types; i++)
{
GSocketControlMessageClass *class;
class = g_type_class_ref (message_types[i]);
message = class->deserialize (level, type, size, data);
g_type_class_unref (class);
if (message != NULL)
break;
}
g_free (message_types);
/* It's not a bug if we can't deserialize the control message - for
* example, the control message may be be discarded if it is deemed
* empty, see e.g.
*
* http://git.gnome.org/browse/glib/commit/?id=ec91ed00f14c70cca9749347b8ebc19d72d9885b
*
* Therefore, it's not appropriate to print a warning about not
* being able to deserialize the message.
*/
return message;
}
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