gio/gsocketservice.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright © 2009 Codethink Limited
   4  * Copyright © 2009 Red Hat, Inc
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser General Public License as published
   8  * by the Free Software Foundation; either version 2 of the licence or (at
   9  * your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General
  17  * Public License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  *
  21  * Authors: Ryan Lortie <desrt@desrt.ca>
  22  *          Alexander Larsson <alexl@redhat.com>
  23  */
  24
  25 /**
  26  * SECTION:gsocketservice
  27  * @title: GSocketService
  28  * @short_description: Make it easy to implement a network service
  29  * @see_also: #GThreadedSocketService, #GSocketListener.
  30  *
  31  * A #GSocketService is an object that represents a service that
  32  * is provided to the network or over local sockets.  When a new
  33  * connection is made to the service the #GSocketService::incoming
  34  * signal is emitted.
  35  *
  36  * A #GSocketService is a subclass of #GSocketListener and you need
  37  * to add the addresses you want to accept connections on with the
  38  * #GSocketListener APIs.
  39  *
  40  * There are two options for implementing a network service based on
  41  * #GSocketService. The first is to create the service using
  42  * g_socket_service_new() and to connect to the #GSocketService::incoming
  43  * signal. The second is to subclass #GSocketService and override the
  44  * default signal handler implementation.
  45  *
  46  * In either case, the handler must immediately return, or else it
  47  * will block additional incoming connections from being serviced.
  48  * If you are interested in writing connection handlers that contain
  49  * blocking code then see #GThreadedSocketService.
  50  *
  51  * The socket service runs on the main loop of the <link
  52  * linkend="g-main-context-push-thread-default-context">thread-default
  53  * context</link> of the thread it is created in, and is not
  54  * threadsafe in general. However, the calls to start and stop the
  55  * service are thread-safe so these can be used from threads that
  56  * handle incoming clients.
  57  *
  58  * Since: 2.22
  59  */
  60
  61 #include "config.h"
  62 #include "gsocketservice.h"
  63
  64 #include <gio/gio.h>
  65 #include "gsocketlistener.h"
  66 #include "gsocketconnection.h"
  67
  68
  69 static guint g_socket_service_incoming_signal;
  70
  71 G_DEFINE_TYPE (GSocketService, g_socket_service, G_TYPE_SOCKET_LISTENER);
  72
  73 G_LOCK_DEFINE_STATIC(active);
  74
  75 struct _GSocketServicePrivate
  76 {
  77   GCancellable *cancellable;
  78   guint active : 1;
  79   guint outstanding_accept : 1;
  80 };
  81
  82 static void g_socket_service_ready (GObject      *object,
  83                                     GAsyncResult *result,
  84                                     gpointer      user_data);
  85
  86 static gboolean
  87 g_socket_service_real_incoming (GSocketService    *service,
  88                                 GSocketConnection *connection,
  89                                 GObject           *source_object)
  90 {
  91   return FALSE;
  92 }
  93
  94 static void
  95 g_socket_service_init (GSocketService *service)
  96 {
  97   service->priv = G_TYPE_INSTANCE_GET_PRIVATE (service,
  98                                                G_TYPE_SOCKET_SERVICE,
  99                                                GSocketServicePrivate);
 100   service->priv->cancellable = g_cancellable_new ();
 101   service->priv->active = TRUE;
 102 }
 103
 104 static void
 105 g_socket_service_finalize (GObject *object)
 106 {
 107   GSocketService *service = G_SOCKET_SERVICE (object);
 108
 109   g_object_unref (service->priv->cancellable);
 110
 111   G_OBJECT_CLASS (g_socket_service_parent_class)
 112     ->finalize (object);
 113 }
 114
 115 static void
 116 do_accept (GSocketService  *service)
 117 {
 118   g_socket_listener_accept_async (G_SOCKET_LISTENER (service),
 119                                   service->priv->cancellable,
 120                                   g_socket_service_ready, NULL);
 121   service->priv->outstanding_accept = TRUE;
 122 }
 123
 124 static void
 125 g_socket_service_changed (GSocketListener *listener)
 126 {
 127   GSocketService  *service = G_SOCKET_SERVICE (listener);
 128
 129   G_LOCK (active);
 130
 131   if (service->priv->active)
 132     {
 133       if (service->priv->outstanding_accept)
 134         g_cancellable_cancel (service->priv->cancellable);
 135       else
 136         {
 137           g_socket_listener_accept_async (listener, service->priv->cancellable,
 138                                           g_socket_service_ready, NULL);
 139           service->priv->outstanding_accept = TRUE;
 140         }
 141     }
 142
 143   G_UNLOCK (active);
 144 }
 145
 146 /**
 147  * g_socket_service_is_active:
 148  * @service: a #GSocketService
 149  *
 150  * Check whether the service is active or not. An active
 151  * service will accept new clients that connect, while
 152  * a non-active service will let connecting clients queue
 153  * up until the service is started.
 154  *
 155  * Returns: %TRUE if the service is active, %FALSE otherwise
 156  *
 157  * Since: 2.22
 158  */
 159 gboolean
 160 g_socket_service_is_active (GSocketService *service)
 161 {
 162   gboolean active;
 163
 164   G_LOCK (active);
 165   active = service->priv->active;
 166   G_UNLOCK (active);
 167   return active;
 168 }
 169
 170 /**
 171  * g_socket_service_start:
 172  * @service: a #GSocketService
 173  *
 174  * Starts the service, i.e. start accepting connections
 175  * from the added sockets when the mainloop runs.
 176  *
 177  * This call is thread-safe, so it may be called from a thread
 178  * handling an incoming client request.
 179  *
 180  * Since: 2.22
 181  */
 182 void
 183 g_socket_service_start (GSocketService *service)
 184 {
 185   G_LOCK (active);
 186
 187   if (!service->priv->active)
 188     {
 189       service->priv->active = TRUE;
 190
 191       if (service->priv->outstanding_accept)
 192         g_cancellable_cancel (service->priv->cancellable);
 193       else
 194         do_accept (service);
 195     }
 196
 197   G_UNLOCK (active);
 198 }
 199
 200 /**
 201  * g_socket_service_stop:
 202  * @service: a #GSocketService
 203  *
 204  * Stops the service, i.e. stops accepting connections
 205  * from the added sockets when the mainloop runs.
 206  *
 207  * This call is thread-safe, so it may be called from a thread
 208  * handling an incoming client request.
 209  *
 210  * Since: 2.22
 211  */
 212 void
 213 g_socket_service_stop (GSocketService *service)
 214 {
 215   G_LOCK (active);
 216
 217   if (service->priv->active)
 218     {
 219       service->priv->active = FALSE;
 220
 221       if (service->priv->outstanding_accept)
 222         g_cancellable_cancel (service->priv->cancellable);
 223     }
 224
 225   G_UNLOCK (active);
 226 }
 227
 228
 229 static gboolean
 230 g_socket_service_incoming (GSocketService    *service,
 231                            GSocketConnection *connection,
 232                            GObject           *source_object)
 233 {
 234   gboolean result;
 235
 236   g_signal_emit (service, g_socket_service_incoming_signal,
 237                  0, connection, source_object, &result);
 238   return result;
 239 }
 240
 241 static void
 242 g_socket_service_class_init (GSocketServiceClass *class)
 243 {
 244   GObjectClass *gobject_class = G_OBJECT_CLASS (class);
 245   GSocketListenerClass *listener_class = G_SOCKET_LISTENER_CLASS (class);
 246
 247   g_type_class_add_private (class, sizeof (GSocketServicePrivate));
 248
 249   gobject_class->finalize = g_socket_service_finalize;
 250   listener_class->changed = g_socket_service_changed;
 251   class->incoming = g_socket_service_real_incoming;
 252
 253   /**
 254    * GSocketService::incoming:
 255    * @service: the #GSocketService
 256    * @connection: a new #GSocketConnection object
 257    * @source_object: (allow-none): the source_object passed to
 258    *     g_socket_listener_add_address()
 259    *
 260    * The ::incoming signal is emitted when a new incoming connection
 261    * to @service needs to be handled. The handler must initiate the
 262    * handling of @connection, but may not block; in essence,
 263    * asynchronous operations must be used.
 264    *
 265    * @connection will be unreffed once the signal handler returns,
 266    * so you need to ref it yourself if you are planning to use it.
 267    *
 268    * Returns: %TRUE to stop other handlers from being called
 269    *
 270    * Since: 2.22
 271    */
 272   g_socket_service_incoming_signal =
 273     g_signal_new ("incoming", G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST,
 274                   G_STRUCT_OFFSET (GSocketServiceClass, incoming),
 275                   g_signal_accumulator_true_handled, NULL,
 276                   NULL, G_TYPE_BOOLEAN,
 277                   2, G_TYPE_SOCKET_CONNECTION, G_TYPE_OBJECT);
 278 }
 279
 280 static void
 281 g_socket_service_ready (GObject      *object,
 282                         GAsyncResult *result,
 283                         gpointer      user_data)
 284 {
 285   GSocketListener *listener = G_SOCKET_LISTENER (object);
 286   GSocketService *service = G_SOCKET_SERVICE (object);
 287   GSocketConnection *connection;
 288   GObject *source_object;
 289   GError *error = NULL;
 290
 291   connection = g_socket_listener_accept_finish (listener, result, &source_object, &error);
 292   if (error)
 293     {
 294       if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
 295         g_warning ("fail: %s", error->message);
 296       g_error_free (error);
 297     }
 298   else
 299     {
 300       g_socket_service_incoming (service, connection, source_object);
 301       g_object_unref (connection);
 302     }
 303
 304   G_LOCK (active);
 305
 306   g_cancellable_reset (service->priv->cancellable);
 307
 308   /* requeue */
 309   service->priv->outstanding_accept = FALSE;
 310   if (service->priv->active)
 311     do_accept (service);
 312
 313   G_UNLOCK (active);
 314 }
 315
 316
 317 /**
 318  * g_socket_service_new:
 319  *
 320  * Creates a new #GSocketService with no sockets to listen for.
 321  * New listeners can be added with e.g. g_socket_listener_add_address()
 322  * or g_socket_listener_add_inet_port().
 323  *
 324  * Returns: a new #GSocketService.
 325  *
 326  * Since: 2.22
 327  */
 328 GSocketService *
 329 g_socket_service_new (void)
 330 {
 331   return g_object_new (G_TYPE_SOCKET_SERVICE, NULL);
 332 }