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glib/gio/gsocketlistener.c
Philip Withnall f1095de46f gsocketlistener: Don’t explicitly close sockets on finalisation 
Instead of closing the sockets explicitly, let them close themselves
when their final reference is dropped. This makes use of
g_socket_listener_add_socket() more natural.

https://bugzilla.gnome.org/show_bug.cgi?id=732107
2014-06-23 16:53:38 +01:00

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright © 2008 Christian Kellner, Samuel Cormier-Iijima
* Copyright © 2009 codethink
* Copyright © 2009 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/>.
*
* Authors: Christian Kellner <gicmo@gnome.org>
* Samuel Cormier-Iijima <sciyoshi@gmail.com>
* Ryan Lortie <desrt@desrt.ca>
* Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include "gsocketlistener.h"
#include <gio/gtask.h>
#include <gio/gcancellable.h>
#include <gio/gsocketaddress.h>
#include <gio/ginetaddress.h>
#include <gio/gioerror.h>
#include <gio/gsocket.h>
#include <gio/gsocketconnection.h>
#include <gio/ginetsocketaddress.h>
#include "glibintl.h"
/**
* SECTION:gsocketlistener
* @title: GSocketListener
* @short_description: Helper for accepting network client connections
* @include: gio/gio.h
* @see_also: #GThreadedSocketService, #GSocketService.
*
* A #GSocketListener is an object that keeps track of a set
* of server sockets and helps you accept sockets from any of the
* socket, either sync or async.
*
* If you want to implement a network server, also look at #GSocketService
* and #GThreadedSocketService which are subclass of #GSocketListener
* that makes this even easier.
*
* Since: 2.22
*/
enum
{
PROP_0,
PROP_LISTEN_BACKLOG
};
static GQuark source_quark = 0;
struct _GSocketListenerPrivate
{
GPtrArray *sockets;
GMainContext *main_context;
int listen_backlog;
guint closed : 1;
};
G_DEFINE_TYPE_WITH_PRIVATE (GSocketListener, g_socket_listener, G_TYPE_OBJECT)
static void
g_socket_listener_finalize (GObject *object)
{
GSocketListener *listener = G_SOCKET_LISTENER (object);
if (listener->priv->main_context)
g_main_context_unref (listener->priv->main_context);
/* Do not explicitly close the sockets. Instead, let them close themselves if
* their final reference is dropped, but keep them open if a reference is
* held externally to the GSocketListener (which is possible if
* g_socket_listener_add_socket() was used).
*/
g_ptr_array_free (listener->priv->sockets, TRUE);
G_OBJECT_CLASS (g_socket_listener_parent_class)
->finalize (object);
}
static void
g_socket_listener_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GSocketListener *listener = G_SOCKET_LISTENER (object);
switch (prop_id)
{
case PROP_LISTEN_BACKLOG:
g_value_set_int (value, listener->priv->listen_backlog);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
g_socket_listener_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GSocketListener *listener = G_SOCKET_LISTENER (object);
switch (prop_id)
{
case PROP_LISTEN_BACKLOG:
g_socket_listener_set_backlog (listener, g_value_get_int (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
}
}
static void
g_socket_listener_class_init (GSocketListenerClass *klass)
{
GObjectClass *gobject_class G_GNUC_UNUSED = G_OBJECT_CLASS (klass);
gobject_class->finalize = g_socket_listener_finalize;
gobject_class->set_property = g_socket_listener_set_property;
gobject_class->get_property = g_socket_listener_get_property;
g_object_class_install_property (gobject_class, PROP_LISTEN_BACKLOG,
g_param_spec_int ("listen-backlog",
P_("Listen backlog"),
P_("outstanding connections in the listen queue"),
0,
2000,
10,
G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
source_quark = g_quark_from_static_string ("g-socket-listener-source");
}
static void
g_socket_listener_init (GSocketListener *listener)
{
listener->priv = g_socket_listener_get_instance_private (listener);
listener->priv->sockets =
g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
listener->priv->listen_backlog = 10;
}
/**
* g_socket_listener_new:
*
* Creates a new #GSocketListener with no sockets to listen for.
* New listeners can be added with e.g. g_socket_listener_add_address()
* or g_socket_listener_add_inet_port().
*
* Returns: a new #GSocketListener.
*
* Since: 2.22
*/
GSocketListener *
g_socket_listener_new (void)
{
return g_object_new (G_TYPE_SOCKET_LISTENER, NULL);
}
static gboolean
check_listener (GSocketListener *listener,
GError **error)
{
if (listener->priv->closed)
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CLOSED,
_("Listener is already closed"));
return FALSE;
}
return TRUE;
}
/**
* g_socket_listener_add_socket:
* @listener: a #GSocketListener
* @socket: a listening #GSocket
* @source_object: (allow-none): Optional #GObject identifying this source
* @error: #GError for error reporting, or %NULL to ignore.
*
* Adds @socket to the set of sockets that we try to accept
* new clients from. The socket must be bound to a local
* address and listened to.
*
* @source_object will be passed out in the various calls
* to accept to identify this particular source, which is
* useful if you're listening on multiple addresses and do
* different things depending on what address is connected to.
*
* The @socket will not be automatically closed when the @listener is finalized
* unless the listener held the final reference to the socket. Before GLib 2.42,
* the @socket was automatically closed on finalization of the @listener, even
* if references to it were held elsewhere.
*
* Returns: %TRUE on success, %FALSE on error.
*
* Since: 2.22
*/
gboolean
g_socket_listener_add_socket (GSocketListener *listener,
GSocket *socket,
GObject *source_object,
GError **error)
{
if (!check_listener (listener, error))
return FALSE;
/* TODO: Check that socket it is bound & not closed? */
if (g_socket_is_closed (socket))
{
g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
_("Added socket is closed"));
return FALSE;
}
g_object_ref (socket);
g_ptr_array_add (listener->priv->sockets, socket);
if (source_object)
g_object_set_qdata_full (G_OBJECT (socket), source_quark,
g_object_ref (source_object), g_object_unref);
if (G_SOCKET_LISTENER_GET_CLASS (listener)->changed)
G_SOCKET_LISTENER_GET_CLASS (listener)->changed (listener);
return TRUE;
}
/**
* g_socket_listener_add_address:
* @listener: a #GSocketListener
* @address: a #GSocketAddress
* @type: a #GSocketType
* @protocol: a #GSocketProtocol
* @source_object: (allow-none): Optional #GObject identifying this source
* @effective_address: (out) (allow-none): location to store the address that was bound to, or %NULL.
* @error: #GError for error reporting, or %NULL to ignore.
*
* Creates a socket of type @type and protocol @protocol, binds
* it to @address and adds it to the set of sockets we're accepting
* sockets from.
*
* Note that adding an IPv6 address, depending on the platform,
* may or may not result in a listener that also accepts IPv4
* connections. For more deterministic behavior, see
* g_socket_listener_add_inet_port().
*
* @source_object will be passed out in the various calls
* to accept to identify this particular source, which is
* useful if you're listening on multiple addresses and do
* different things depending on what address is connected to.
*
* If successful and @effective_address is non-%NULL then it will
* be set to the address that the binding actually occurred at. This
* is helpful for determining the port number that was used for when
* requesting a binding to port 0 (ie: "any port"). This address, if
* requested, belongs to the caller and must be freed.
*
* Returns: %TRUE on success, %FALSE on error.
*
* Since: 2.22
*/
gboolean
g_socket_listener_add_address (GSocketListener *listener,
GSocketAddress *address,
GSocketType type,
GSocketProtocol protocol,
GObject *source_object,
GSocketAddress **effective_address,
GError **error)
{
GSocketAddress *local_address;
GSocketFamily family;
GSocket *socket;
if (!check_listener (listener, error))
return FALSE;
family = g_socket_address_get_family (address);
socket = g_socket_new (family, type, protocol, error);
if (socket == NULL)
return FALSE;
g_socket_set_listen_backlog (socket, listener->priv->listen_backlog);
if (!g_socket_bind (socket, address, TRUE, error) ||
!g_socket_listen (socket, error))
{
g_object_unref (socket);
return FALSE;
}
local_address = NULL;
if (effective_address)
{
local_address = g_socket_get_local_address (socket, error);
if (local_address == NULL)
{
g_object_unref (socket);
return FALSE;
}
}
if (!g_socket_listener_add_socket (listener, socket,
source_object,
error))
{
if (local_address)
g_object_unref (local_address);
g_object_unref (socket);
return FALSE;
}
if (effective_address)
*effective_address = local_address;
g_object_unref (socket); /* add_socket refs this */
return TRUE;
}
/**
* g_socket_listener_add_inet_port:
* @listener: a #GSocketListener
* @port: an IP port number (non-zero)
* @source_object: (allow-none): Optional #GObject identifying this source
* @error: #GError for error reporting, or %NULL to ignore.
*
* Helper function for g_socket_listener_add_address() that
* creates a TCP/IP socket listening on IPv4 and IPv6 (if
* supported) on the specified port on all interfaces.
*
* @source_object will be passed out in the various calls
* to accept to identify this particular source, which is
* useful if you're listening on multiple addresses and do
* different things depending on what address is connected to.
*
* Returns: %TRUE on success, %FALSE on error.
*
* Since: 2.22
*/
gboolean
g_socket_listener_add_inet_port (GSocketListener *listener,
guint16 port,
GObject *source_object,
GError **error)
{
gboolean need_ipv4_socket = TRUE;
GSocket *socket4 = NULL;
GSocket *socket6;
g_return_val_if_fail (listener != NULL, FALSE);
g_return_val_if_fail (port != 0, FALSE);
if (!check_listener (listener, error))
return FALSE;
/* first try to create an IPv6 socket */
socket6 = g_socket_new (G_SOCKET_FAMILY_IPV6,
G_SOCKET_TYPE_STREAM,
G_SOCKET_PROTOCOL_DEFAULT,
NULL);
if (socket6 != NULL)
/* IPv6 is supported on this platform, so if we fail now it is
* a result of being unable to bind to our port. Don't fail
* silently as a result of this!
*/
{
GInetAddress *inet_address;
GSocketAddress *address;
gboolean result;
inet_address = g_inet_address_new_any (G_SOCKET_FAMILY_IPV6);
address = g_inet_socket_address_new (inet_address, port);
g_object_unref (inet_address);
g_socket_set_listen_backlog (socket6, listener->priv->listen_backlog);
result = g_socket_bind (socket6, address, TRUE, error) &&
g_socket_listen (socket6, error);
g_object_unref (address);
if (!result)
{
g_object_unref (socket6);
return FALSE;
}
if (source_object)
g_object_set_qdata_full (G_OBJECT (socket6), source_quark,
g_object_ref (source_object),
g_object_unref);
/* If this socket already speaks IPv4 then we are done. */
if (g_socket_speaks_ipv4 (socket6))
need_ipv4_socket = FALSE;
}
if (need_ipv4_socket)
/* We are here for exactly one of the following reasons:
*
* - our platform doesn't support IPv6
* - we successfully created an IPv6 socket but it's V6ONLY
*
* In either case, we need to go ahead and create an IPv4 socket
* and fail the call if we can't bind to it.
*/
{
socket4 = g_socket_new (G_SOCKET_FAMILY_IPV4,
G_SOCKET_TYPE_STREAM,
G_SOCKET_PROTOCOL_DEFAULT,
error);
if (socket4 != NULL)
/* IPv4 is supported on this platform, so if we fail now it is
* a result of being unable to bind to our port. Don't fail
* silently as a result of this!
*/
{
GInetAddress *inet_address;
GSocketAddress *address;
gboolean result;
inet_address = g_inet_address_new_any (G_SOCKET_FAMILY_IPV4);
address = g_inet_socket_address_new (inet_address, port);
g_object_unref (inet_address);
g_socket_set_listen_backlog (socket4,
listener->priv->listen_backlog);
result = g_socket_bind (socket4, address, TRUE, error) &&
g_socket_listen (socket4, error);
g_object_unref (address);
if (!result)
{
g_object_unref (socket4);
if (socket6 != NULL)
g_object_unref (socket6);
return FALSE;
}
if (source_object)
g_object_set_qdata_full (G_OBJECT (socket4), source_quark,
g_object_ref (source_object),
g_object_unref);
}
else
/* Ok. So IPv4 is not supported on this platform. If we
* succeeded at creating an IPv6 socket then that's OK, but
* otherwise we need to tell the user we failed.
*/
{
if (socket6 != NULL)
g_clear_error (error);
else
return FALSE;
}
}
g_assert (socket6 != NULL || socket4 != NULL);
if (socket6 != NULL)
g_ptr_array_add (listener->priv->sockets, socket6);
if (socket4 != NULL)
g_ptr_array_add (listener->priv->sockets, socket4);
if (G_SOCKET_LISTENER_GET_CLASS (listener)->changed)
G_SOCKET_LISTENER_GET_CLASS (listener)->changed (listener);
return TRUE;
}
static GList *
add_sources (GSocketListener *listener,
GSocketSourceFunc callback,
gpointer callback_data,
GCancellable *cancellable,
GMainContext *context)
{
GSocket *socket;
GSource *source;
GList *sources;
int i;
sources = NULL;
for (i = 0; i < listener->priv->sockets->len; i++)
{
socket = listener->priv->sockets->pdata[i];
source = g_socket_create_source (socket, G_IO_IN, cancellable);
g_source_set_callback (source,
(GSourceFunc) callback,
callback_data, NULL);
g_source_attach (source, context);
sources = g_list_prepend (sources, source);
}
return sources;
}
static void
free_sources (GList *sources)
{
GSource *source;
while (sources != NULL)
{
source = sources->data;
sources = g_list_delete_link (sources, sources);
g_source_destroy (source);
g_source_unref (source);
}
}
struct AcceptData {
GMainLoop *loop;
GSocket *socket;
};
static gboolean
accept_callback (GSocket *socket,
GIOCondition condition,
gpointer user_data)
{
struct AcceptData *data = user_data;
data->socket = socket;
g_main_loop_quit (data->loop);
return TRUE;
}
/**
* g_socket_listener_accept_socket:
* @listener: a #GSocketListener
* @source_object: (out) (transfer none) (allow-none): location where #GObject pointer will be stored, or %NULL.
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: #GError for error reporting, or %NULL to ignore.
*
* Blocks waiting for a client to connect to any of the sockets added
* to the listener. Returns the #GSocket that was accepted.
*
* If you want to accept the high-level #GSocketConnection, not a #GSocket,
* which is often the case, then you should use g_socket_listener_accept()
* instead.
*
* If @source_object is not %NULL it will be filled out with the source
* object specified when the corresponding socket or address was added
* to the listener.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
*
* Returns: (transfer full): a #GSocket on success, %NULL on error.
*
* Since: 2.22
*/
GSocket *
g_socket_listener_accept_socket (GSocketListener *listener,
GObject **source_object,
GCancellable *cancellable,
GError **error)
{
GSocket *accept_socket, *socket;
g_return_val_if_fail (G_IS_SOCKET_LISTENER (listener), NULL);
if (!check_listener (listener, error))
return NULL;
if (listener->priv->sockets->len == 1)
{
accept_socket = listener->priv->sockets->pdata[0];
if (!g_socket_condition_wait (accept_socket, G_IO_IN,
cancellable, error))
return NULL;
}
else
{
GList *sources;
struct AcceptData data;
GMainLoop *loop;
if (listener->priv->main_context == NULL)
listener->priv->main_context = g_main_context_new ();
loop = g_main_loop_new (listener->priv->main_context, FALSE);
data.loop = loop;
sources = add_sources (listener,
accept_callback,
&data,
cancellable,
listener->priv->main_context);
g_main_loop_run (loop);
accept_socket = data.socket;
free_sources (sources);
g_main_loop_unref (loop);
}
if (!(socket = g_socket_accept (accept_socket, cancellable, error)))
return NULL;
if (source_object)
*source_object = g_object_get_qdata (G_OBJECT (accept_socket), source_quark);
return socket;
}
/**
* g_socket_listener_accept:
* @listener: a #GSocketListener
* @source_object: (out) (transfer none) (allow-none): location where #GObject pointer will be stored, or %NULL
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
* @error: #GError for error reporting, or %NULL to ignore.
*
* Blocks waiting for a client to connect to any of the sockets added
* to the listener. Returns a #GSocketConnection for the socket that was
* accepted.
*
* If @source_object is not %NULL it will be filled out with the source
* object specified when the corresponding socket or address was added
* to the listener.
*
* If @cancellable is not %NULL, then the operation can be cancelled by
* triggering the cancellable object from another thread. If the operation
* was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
*
* Returns: (transfer full): a #GSocketConnection on success, %NULL on error.
*
* Since: 2.22
*/
GSocketConnection *
g_socket_listener_accept (GSocketListener *listener,
GObject **source_object,
GCancellable *cancellable,
GError **error)
{
GSocketConnection *connection;
GSocket *socket;
socket = g_socket_listener_accept_socket (listener,
source_object,
cancellable,
error);
if (socket == NULL)
return NULL;
connection = g_socket_connection_factory_create_connection (socket);
g_object_unref (socket);
return connection;
}
static gboolean
accept_ready (GSocket *accept_socket,
GIOCondition condition,
gpointer user_data)
{
GTask *task = user_data;
GError *error = NULL;
GSocket *socket;
GObject *source_object;
socket = g_socket_accept (accept_socket, g_task_get_cancellable (task), &error);
if (socket)
{
source_object = g_object_get_qdata (G_OBJECT (accept_socket), source_quark);
if (source_object)
g_object_set_qdata_full (G_OBJECT (task),
source_quark,
g_object_ref (source_object), g_object_unref);
g_task_return_pointer (task, socket, g_object_unref);
}
else
{
g_task_return_error (task, error);
}
g_object_unref (task);
return FALSE;
}
/**
* g_socket_listener_accept_socket_async:
* @listener: a #GSocketListener
* @cancellable: (allow-none): a #GCancellable, or %NULL
* @callback: (scope async): a #GAsyncReadyCallback
* @user_data: (closure): user data for the callback
*
* This is the asynchronous version of g_socket_listener_accept_socket().
*
* When the operation is finished @callback will be
* called. You can then call g_socket_listener_accept_socket_finish()
* to get the result of the operation.
*
* Since: 2.22
*/
void
g_socket_listener_accept_socket_async (GSocketListener *listener,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GTask *task;
GList *sources;
GError *error = NULL;
task = g_task_new (listener, cancellable, callback, user_data);
if (!check_listener (listener, &error))
{
g_task_return_error (task, error);
g_object_unref (task);
return;
}
sources = add_sources (listener,
accept_ready,
task,
cancellable,
g_main_context_get_thread_default ());
g_task_set_task_data (task, sources, (GDestroyNotify) free_sources);
}
/**
* g_socket_listener_accept_socket_finish:
* @listener: a #GSocketListener
* @result: a #GAsyncResult.
* @source_object: (out) (transfer none) (allow-none): Optional #GObject identifying this source
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an async accept operation. See g_socket_listener_accept_socket_async()
*
* Returns: (transfer full): a #GSocket on success, %NULL on error.
*
* Since: 2.22
*/
GSocket *
g_socket_listener_accept_socket_finish (GSocketListener *listener,
GAsyncResult *result,
GObject **source_object,
GError **error)
{
g_return_val_if_fail (G_IS_SOCKET_LISTENER (listener), NULL);
g_return_val_if_fail (g_task_is_valid (result, listener), NULL);
if (source_object)
*source_object = g_object_get_qdata (G_OBJECT (result), source_quark);
return g_task_propagate_pointer (G_TASK (result), error);
}
/**
* g_socket_listener_accept_async:
* @listener: a #GSocketListener
* @cancellable: (allow-none): a #GCancellable, or %NULL
* @callback: (scope async): a #GAsyncReadyCallback
* @user_data: (closure): user data for the callback
*
* This is the asynchronous version of g_socket_listener_accept().
*
* When the operation is finished @callback will be
* called. You can then call g_socket_listener_accept_socket()
* to get the result of the operation.
*
* Since: 2.22
*/
void
g_socket_listener_accept_async (GSocketListener *listener,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
g_socket_listener_accept_socket_async (listener,
cancellable,
callback,
user_data);
}
/**
* g_socket_listener_accept_finish:
* @listener: a #GSocketListener
* @result: a #GAsyncResult.
* @source_object: (out) (transfer none) (allow-none): Optional #GObject identifying this source
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Finishes an async accept operation. See g_socket_listener_accept_async()
*
* Returns: (transfer full): a #GSocketConnection on success, %NULL on error.
*
* Since: 2.22
*/
GSocketConnection *
g_socket_listener_accept_finish (GSocketListener *listener,
GAsyncResult *result,
GObject **source_object,
GError **error)
{
GSocket *socket;
GSocketConnection *connection;
socket = g_socket_listener_accept_socket_finish (listener,
result,
source_object,
error);
if (socket == NULL)
return NULL;
connection = g_socket_connection_factory_create_connection (socket);
g_object_unref (socket);
return connection;
}
/**
* g_socket_listener_set_backlog:
* @listener: a #GSocketListener
* @listen_backlog: an integer
*
* Sets the listen backlog on the sockets in the listener.
*
* See g_socket_set_listen_backlog() for details
*
* Since: 2.22
*/
void
g_socket_listener_set_backlog (GSocketListener *listener,
int listen_backlog)
{
GSocket *socket;
int i;
if (listener->priv->closed)
return;
listener->priv->listen_backlog = listen_backlog;
for (i = 0; i < listener->priv->sockets->len; i++)
{
socket = listener->priv->sockets->pdata[i];
g_socket_set_listen_backlog (socket, listen_backlog);
}
}
/**
* g_socket_listener_close:
* @listener: a #GSocketListener
*
* Closes all the sockets in the listener.
*
* Since: 2.22
*/
void
g_socket_listener_close (GSocketListener *listener)
{
GSocket *socket;
int i;
g_return_if_fail (G_IS_SOCKET_LISTENER (listener));
if (listener->priv->closed)
return;
for (i = 0; i < listener->priv->sockets->len; i++)
{
socket = listener->priv->sockets->pdata[i];
g_socket_close (socket, NULL);
}
listener->priv->closed = TRUE;
}
/**
* g_socket_listener_add_any_inet_port:
* @listener: a #GSocketListener
* @source_object: (allow-none): Optional #GObject identifying this source
* @error: a #GError location to store the error occurring, or %NULL to
* ignore.
*
* Listens for TCP connections on any available port number for both
* IPv6 and IPv4 (if each is available).
*
* This is useful if you need to have a socket for incoming connections
* but don't care about the specific port number.
*
* @source_object will be passed out in the various calls
* to accept to identify this particular source, which is
* useful if you're listening on multiple addresses and do
* different things depending on what address is connected to.
*
* Returns: the port number, or 0 in case of failure.
*
* Since: 2.24
**/
guint16
g_socket_listener_add_any_inet_port (GSocketListener *listener,
GObject *source_object,
GError **error)
{
GSList *sockets_to_close = NULL;
guint16 candidate_port = 0;
GSocket *socket6 = NULL;
GSocket *socket4 = NULL;
gint attempts = 37;
/*
* multi-step process:
* - first, create an IPv6 socket.
* - if that fails, create an IPv4 socket and bind it to port 0 and
* that's it. no retries if that fails (why would it?).
* - if our IPv6 socket also speaks IPv4 then we are done.
* - if not, then we need to create a IPv4 socket with the same port
* number. this might fail, of course. so we try this a bunch of
* times -- leaving the old IPv6 sockets open so that we get a
* different port number to try each time.
* - if all that fails then just give up.
*/
while (attempts--)
{
GInetAddress *inet_address;
GSocketAddress *address;
gboolean result;
g_assert (socket6 == NULL);
socket6 = g_socket_new (G_SOCKET_FAMILY_IPV6,
G_SOCKET_TYPE_STREAM,
G_SOCKET_PROTOCOL_DEFAULT,
NULL);
if (socket6 != NULL)
{
inet_address = g_inet_address_new_any (G_SOCKET_FAMILY_IPV6);
address = g_inet_socket_address_new (inet_address, 0);
g_object_unref (inet_address);
result = g_socket_bind (socket6, address, TRUE, error);
g_object_unref (address);
if (!result ||
!(address = g_socket_get_local_address (socket6, error)))
{
g_object_unref (socket6);
socket6 = NULL;
break;
}
g_assert (G_IS_INET_SOCKET_ADDRESS (address));
candidate_port =
g_inet_socket_address_get_port (G_INET_SOCKET_ADDRESS (address));
g_assert (candidate_port != 0);
g_object_unref (address);
if (g_socket_speaks_ipv4 (socket6))
break;
}
g_assert (socket4 == NULL);
socket4 = g_socket_new (G_SOCKET_FAMILY_IPV4,
G_SOCKET_TYPE_STREAM,
G_SOCKET_PROTOCOL_DEFAULT,
socket6 ? NULL : error);
if (socket4 == NULL)
/* IPv4 not supported.
* if IPv6 is supported then candidate_port will be non-zero
* (and the error parameter above will have been NULL)
* if IPv6 is unsupported then candidate_port will be zero
* (and error will have been set by the above call)
*/
break;
inet_address = g_inet_address_new_any (G_SOCKET_FAMILY_IPV4);
address = g_inet_socket_address_new (inet_address, candidate_port);
g_object_unref (inet_address);
/* a note on the 'error' clause below:
*
* if candidate_port is 0 then we report the error right away
* since it is strange that this binding would fail at all.
* otherwise, we ignore the error message (ie: NULL).
*
* the exception to this rule is the last time through the loop
* (ie: attempts == 0) in which case we want to set the error
* because failure here means that the entire call will fail and
* we need something to show to the user.
*
* an english summary of the situation: "if we gave a candidate
* port number AND we have more attempts to try, then ignore the
* error for now".
*/
result = g_socket_bind (socket4, address, TRUE,
(candidate_port && attempts) ? NULL : error);
g_object_unref (address);
if (candidate_port)
{
g_assert (socket6 != NULL);
if (result)
/* got our candidate port successfully */
break;
else
/* we failed to bind to the specified port. try again. */
{
g_object_unref (socket4);
socket4 = NULL;
/* keep this open so we get a different port number */
sockets_to_close = g_slist_prepend (sockets_to_close,
socket6);
candidate_port = 0;
socket6 = NULL;
}
}
else
/* we didn't tell it a port. this means two things.
* - if we failed, then something really bad happened.
* - if we succeeded, then we need to find out the port number.
*/
{
g_assert (socket6 == NULL);
if (!result ||
!(address = g_socket_get_local_address (socket4, error)))
{
g_object_unref (socket4);
socket4 = NULL;
break;
}
g_assert (G_IS_INET_SOCKET_ADDRESS (address));
candidate_port =
g_inet_socket_address_get_port (G_INET_SOCKET_ADDRESS (address));
g_assert (candidate_port != 0);
g_object_unref (address);
break;
}
}
/* should only be non-zero if we have a socket */
g_assert ((candidate_port != 0) == (socket4 || socket6));
while (sockets_to_close)
{
g_object_unref (sockets_to_close->data);
sockets_to_close = g_slist_delete_link (sockets_to_close,
sockets_to_close);
}
/* now we actually listen() the sockets and add them to the listener */
if (socket6 != NULL)
{
g_socket_set_listen_backlog (socket6, listener->priv->listen_backlog);
if (!g_socket_listen (socket6, error))
{
g_object_unref (socket6);
if (socket4)
g_object_unref (socket4);
return 0;
}
if (source_object)
g_object_set_qdata_full (G_OBJECT (socket6), source_quark,
g_object_ref (source_object),
g_object_unref);
g_ptr_array_add (listener->priv->sockets, socket6);
}
if (socket4 != NULL)
{
g_socket_set_listen_backlog (socket4, listener->priv->listen_backlog);
if (!g_socket_listen (socket4, error))
{
g_object_unref (socket4);
if (socket6)
g_object_unref (socket6);
return 0;
}
if (source_object)
g_object_set_qdata_full (G_OBJECT (socket4), source_quark,
g_object_ref (source_object),
g_object_unref);
g_ptr_array_add (listener->priv->sockets, socket4);
}
if ((socket4 != NULL || socket6 != NULL) &&
G_SOCKET_LISTENER_GET_CLASS (listener)->changed)
G_SOCKET_LISTENER_GET_CLASS (listener)->changed (listener);
return candidate_port;
}
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