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, see <http://www.gnu.org/licenses/>.
  18  *
  19  * Authors: Ryan Lortie <desrt@desrt.ca>
  20  *          Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 /**
  24  * SECTION:gsocketservice
  25  * @title: GSocketService
  26  * @short_description: Make it easy to implement a network service
  27  * @include: gio/gio.h
  28  * @see_also: #GThreadedSocketService, #GSocketListener.
  29  *
  30  * A #GSocketService is an object that represents a service that
  31  * is provided to the network or over local sockets.  When a new
  32  * connection is made to the service the #GSocketService::incoming
  33  * signal is emitted.
  34  *
  35  * A #GSocketService is a subclass of #GSocketListener and you need
  36  * to add the addresses you want to accept connections on with the
  37  * #GSocketListener APIs.
  38  *
  39  * There are two options for implementing a network service based on
  40  * #GSocketService. The first is to create the service using
  41  * g_socket_service_new() and to connect to the #GSocketService::incoming
  42  * signal. The second is to subclass #GSocketService and override the
  43  * default signal handler implementation.
  44  *
  45  * In either case, the handler must immediately return, or else it
  46  * will block additional incoming connections from being serviced.
  47  * If you are interested in writing connection handlers that contain
  48  * blocking code then see #GThreadedSocketService.
  49  *
  50  * The socket service runs on the main loop of the
  51  * [thread-default context][g-main-context-push-thread-default-context]
  52  * of the thread it is created in, and is not
  53  * threadsafe in general. However, the calls to start and stop the
  54  * service are thread-safe so these can be used from threads that
  55  * handle incoming clients.
  56  *
  57  * Since: 2.22
  58  */
  59
  60 #include "config.h"
  61 #include "gsocketservice.h"
  62
  63 #include <gio/gio.h>
  64 #include "gsocketlistener.h"
  65 #include "gsocketconnection.h"
  66 #include "glibintl.h"
  67
  68 struct _GSocketServicePrivate
  69 {
  70   GCancellable *cancellable;
  71   guint active : 1;
  72   guint outstanding_accept : 1;
  73 };
  74
  75 static guint g_socket_service_incoming_signal;
  76
  77 G_LOCK_DEFINE_STATIC(active);
  78
  79 G_DEFINE_TYPE_WITH_PRIVATE (GSocketService, g_socket_service, G_TYPE_SOCKET_LISTENER)
  80
  81 enum
  82 {
  83   PROP_0,
  84   PROP_ACTIVE
  85 };
  86
  87 static void g_socket_service_ready (GObject      *object,
  88                                     GAsyncResult *result,
  89                                     gpointer      user_data);
  90
  91 static gboolean
  92 g_socket_service_real_incoming (GSocketService    *service,
  93                                 GSocketConnection *connection,
  94                                 GObject           *source_object)
  95 {
  96   return FALSE;
  97 }
  98
  99 static void
 100 g_socket_service_init (GSocketService *service)
 101 {
 102   service->priv = g_socket_service_get_instance_private (service);
 103   service->priv->cancellable = g_cancellable_new ();
 104   service->priv->active = TRUE;
 105 }
 106
 107 static void
 108 g_socket_service_finalize (GObject *object)
 109 {
 110   GSocketService *service = G_SOCKET_SERVICE (object);
 111
 112   g_object_unref (service->priv->cancellable);
 113
 114   G_OBJECT_CLASS (g_socket_service_parent_class)
 115     ->finalize (object);
 116 }
 117
 118 static void
 119 do_accept (GSocketService  *service)
 120 {
 121   g_socket_listener_accept_async (G_SOCKET_LISTENER (service),
 122                                   service->priv->cancellable,
 123                                   g_socket_service_ready, NULL);
 124   service->priv->outstanding_accept = TRUE;
 125 }
 126
 127 static gboolean
 128 get_active (GSocketService *service)
 129 {
 130   gboolean active;
 131
 132   G_LOCK (active);
 133   active = service->priv->active;
 134   G_UNLOCK (active);
 135
 136   return active;
 137 }
 138
 139 static void
 140 set_active (GSocketService *service, gboolean active)
 141 {
 142   gboolean notify = FALSE;
 143
 144   active = !!active;
 145
 146   G_LOCK (active);
 147
 148   if (active != service->priv->active)
 149     {
 150       service->priv->active = active;
 151       notify = TRUE;
 152
 153       if (active)
 154         {
 155           if (service->priv->outstanding_accept)
 156             g_cancellable_cancel (service->priv->cancellable);
 157           else
 158             do_accept (service);
 159         }
 160       else
 161         {
 162           if (service->priv->outstanding_accept)
 163             g_cancellable_cancel (service->priv->cancellable);
 164         }
 165     }
 166
 167   G_UNLOCK (active);
 168
 169   if (notify)
 170     g_object_notify (G_OBJECT (service), "active");
 171 }
 172
 173 static void
 174 g_socket_service_get_property (GObject    *object,
 175                                guint       prop_id,
 176                                GValue     *value,
 177                                GParamSpec *pspec)
 178 {
 179   GSocketService *service = G_SOCKET_SERVICE (object);
 180
 181   switch (prop_id)
 182     {
 183     case PROP_ACTIVE:
 184       g_value_set_boolean (value, get_active (service));
 185       break;
 186     default:
 187       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 188       break;
 189     }
 190 }
 191
 192 static void
 193 g_socket_service_set_property (GObject      *object,
 194                                guint         prop_id,
 195                                const GValue *value,
 196                                GParamSpec   *pspec)
 197 {
 198   GSocketService *service = G_SOCKET_SERVICE (object);
 199
 200   switch (prop_id)
 201     {
 202     case PROP_ACTIVE:
 203       set_active (service, g_value_get_boolean (value));
 204       break;
 205     default:
 206       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 207       break;
 208     }
 209 }
 210
 211 static void
 212 g_socket_service_changed (GSocketListener *listener)
 213 {
 214   GSocketService  *service = G_SOCKET_SERVICE (listener);
 215
 216   G_LOCK (active);
 217
 218   if (service->priv->active)
 219     {
 220       if (service->priv->outstanding_accept)
 221         g_cancellable_cancel (service->priv->cancellable);
 222       else
 223         do_accept (service);
 224     }
 225
 226   G_UNLOCK (active);
 227 }
 228
 229 /**
 230  * g_socket_service_is_active:
 231  * @service: a #GSocketService
 232  *
 233  * Check whether the service is active or not. An active
 234  * service will accept new clients that connect, while
 235  * a non-active service will let connecting clients queue
 236  * up until the service is started.
 237  *
 238  * Returns: %TRUE if the service is active, %FALSE otherwise
 239  *
 240  * Since: 2.22
 241  */
 242 gboolean
 243 g_socket_service_is_active (GSocketService *service)
 244 {
 245   g_return_val_if_fail (G_IS_SOCKET_SERVICE (service), FALSE);
 246
 247   return get_active (service);
 248 }
 249
 250 /**
 251  * g_socket_service_start:
 252  * @service: a #GSocketService
 253  *
 254  * Restarts the service, i.e. start accepting connections
 255  * from the added sockets when the mainloop runs. This only needs
 256  * to be called after the service has been stopped from
 257  * g_socket_service_stop().
 258  *
 259  * This call is thread-safe, so it may be called from a thread
 260  * handling an incoming client request.
 261  *
 262  * Since: 2.22
 263  */
 264 void
 265 g_socket_service_start (GSocketService *service)
 266 {
 267   g_return_if_fail (G_IS_SOCKET_SERVICE (service));
 268
 269   set_active (service, TRUE);
 270 }
 271
 272 /**
 273  * g_socket_service_stop:
 274  * @service: a #GSocketService
 275  *
 276  * Stops the service, i.e. stops accepting connections
 277  * from the added sockets when the mainloop runs.
 278  *
 279  * This call is thread-safe, so it may be called from a thread
 280  * handling an incoming client request.
 281  *
 282  * Note that this only stops accepting new connections; it does not
 283  * close the listening sockets, and you can call
 284  * g_socket_service_start() again later to begin listening again. To
 285  * close the listening sockets, call g_socket_listener_close(). (This
 286  * will happen automatically when the #GSocketService is finalized.)
 287  *
 288  * This must be called before calling g_socket_listener_close() as
 289  * the socket service will start accepting connections immediately
 290  * when a new socket is added.
 291  *
 292  * Since: 2.22
 293  */
 294 void
 295 g_socket_service_stop (GSocketService *service)
 296 {
 297   g_return_if_fail (G_IS_SOCKET_SERVICE (service));
 298
 299   set_active (service, FALSE);
 300 }
 301
 302 static gboolean
 303 g_socket_service_incoming (GSocketService    *service,
 304                            GSocketConnection *connection,
 305                            GObject           *source_object)
 306 {
 307   gboolean result;
 308
 309   g_signal_emit (service, g_socket_service_incoming_signal,
 310                  0, connection, source_object, &result);
 311   return result;
 312 }
 313
 314 static void
 315 g_socket_service_class_init (GSocketServiceClass *class)
 316 {
 317   GObjectClass *gobject_class = G_OBJECT_CLASS (class);
 318   GSocketListenerClass *listener_class = G_SOCKET_LISTENER_CLASS (class);
 319
 320   gobject_class->finalize = g_socket_service_finalize;
 321   gobject_class->set_property = g_socket_service_set_property;
 322   gobject_class->get_property = g_socket_service_get_property;
 323   listener_class->changed = g_socket_service_changed;
 324   class->incoming = g_socket_service_real_incoming;
 325
 326   /**
 327    * GSocketService::incoming:
 328    * @service: the #GSocketService
 329    * @connection: a new #GSocketConnection object
 330    * @source_object: (nullable): the source_object passed to
 331    *     g_socket_listener_add_address()
 332    *
 333    * The ::incoming signal is emitted when a new incoming connection
 334    * to @service needs to be handled. The handler must initiate the
 335    * handling of @connection, but may not block; in essence,
 336    * asynchronous operations must be used.
 337    *
 338    * @connection will be unreffed once the signal handler returns,
 339    * so you need to ref it yourself if you are planning to use it.
 340    *
 341    * Returns: %TRUE to stop other handlers from being called
 342    *
 343    * Since: 2.22
 344    */
 345   g_socket_service_incoming_signal =
 346     g_signal_new (I_("incoming"), G_TYPE_FROM_CLASS (class), G_SIGNAL_RUN_LAST,
 347                   G_STRUCT_OFFSET (GSocketServiceClass, incoming),
 348                   g_signal_accumulator_true_handled, NULL,
 349                   NULL, G_TYPE_BOOLEAN,
 350                   2, G_TYPE_SOCKET_CONNECTION, G_TYPE_OBJECT);
 351
 352   /**
 353    * GSocketService:active:
 354    *
 355    * Whether the service is currently accepting connections.
 356    *
 357    * Since: 2.46
 358    */
 359   g_object_class_install_property (gobject_class, PROP_ACTIVE,
 360                                    g_param_spec_boolean ("active",
 361                                                          P_("Active"),
 362                                                          P_("Whether the service is currently accepting connections"),
 363                                                          TRUE,
 364                                                          G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 365 }
 366
 367 static void
 368 g_socket_service_ready (GObject      *object,
 369                         GAsyncResult *result,
 370                         gpointer      user_data)
 371 {
 372   GSocketListener *listener = G_SOCKET_LISTENER (object);
 373   GSocketService *service = G_SOCKET_SERVICE (object);
 374   GSocketConnection *connection;
 375   GObject *source_object;
 376   GError *error = NULL;
 377
 378   connection = g_socket_listener_accept_finish (listener, result, &source_object, &error);
 379   if (error)
 380     {
 381       if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
 382         g_warning ("fail: %s", error->message);
 383       g_error_free (error);
 384     }
 385   else
 386     {
 387       g_socket_service_incoming (service, connection, source_object);
 388       g_object_unref (connection);
 389     }
 390
 391   G_LOCK (active);
 392
 393   g_cancellable_reset (service->priv->cancellable);
 394
 395   /* requeue */
 396   service->priv->outstanding_accept = FALSE;
 397   if (service->priv->active)
 398     do_accept (service);
 399
 400   G_UNLOCK (active);
 401 }
 402
 403 /**
 404  * g_socket_service_new:
 405  *
 406  * Creates a new #GSocketService with no sockets to listen for.
 407  * New listeners can be added with e.g. g_socket_listener_add_address()
 408  * or g_socket_listener_add_inet_port().
 409  *
 410  * New services are created active, there is no need to call
 411  * g_socket_service_start(), unless g_socket_service_stop() has been
 412  * called before.
 413  *
 414  * Returns: a new #GSocketService.
 415  *
 416  * Since: 2.22
 417  */
 418 GSocketService *
 419 g_socket_service_new (void)
 420 {
 421   return g_object_new (G_TYPE_SOCKET_SERVICE, NULL);
 422 }