gio/gdbusprivate.c

   1 /* GDBus - GLib D-Bus Library
   2  *
   3  * Copyright (C) 2008-2010 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: David Zeuthen <davidz@redhat.com>
  21  */
  22
  23 #include "config.h"
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #ifdef HAVE_UNISTD_H
  28 #include <unistd.h>
  29 #endif
  30
  31 #include "giotypes.h"
  32 #include "gsocket.h"
  33 #include "gdbusprivate.h"
  34 #include "gdbusmessage.h"
  35 #include "gdbuserror.h"
  36 #include "gdbusintrospection.h"
  37 #include "gasyncresult.h"
  38 #include "gsimpleasyncresult.h"
  39 #include "ginputstream.h"
  40 #include "gmemoryinputstream.h"
  41 #include "giostream.h"
  42 #include "gsocketcontrolmessage.h"
  43 #include "gsocketconnection.h"
  44 #include "gsocketoutputstream.h"
  45
  46 #ifdef G_OS_UNIX
  47 #include "gunixfdmessage.h"
  48 #include "gunixconnection.h"
  49 #include "gunixcredentialsmessage.h"
  50 #endif
  51
  52 #ifdef G_OS_WIN32
  53 #include <windows.h>
  54 #endif
  55
  56 #include "glibintl.h"
  57
  58 static gboolean _g_dbus_worker_do_initial_read (gpointer data);
  59
  60 /* ---------------------------------------------------------------------------------------------------- */
  61
  62 gchar *
  63 _g_dbus_hexdump (const gchar *data, gsize len, guint indent)
  64 {
  65  guint n, m;
  66  GString *ret;
  67
  68  ret = g_string_new (NULL);
  69
  70  for (n = 0; n < len; n += 16)
  71    {
  72      g_string_append_printf (ret, "%*s%04x: ", indent, "", n);
  73
  74      for (m = n; m < n + 16; m++)
  75        {
  76          if (m > n && (m%4) == 0)
  77            g_string_append_c (ret, ' ');
  78          if (m < len)
  79            g_string_append_printf (ret, "%02x ", (guchar) data[m]);
  80          else
  81            g_string_append (ret, "   ");
  82        }
  83
  84      g_string_append (ret, "   ");
  85
  86      for (m = n; m < len && m < n + 16; m++)
  87        g_string_append_c (ret, g_ascii_isprint (data[m]) ? data[m] : '.');
  88
  89      g_string_append_c (ret, '\n');
  90    }
  91
  92  return g_string_free (ret, FALSE);
  93 }
  94
  95 /* ---------------------------------------------------------------------------------------------------- */
  96
  97 /* Unfortunately ancillary messages are discarded when reading from a
  98  * socket using the GSocketInputStream abstraction. So we provide a
  99  * very GInputStream-ish API that uses GSocket in this case (very
 100  * similar to GSocketInputStream).
 101  */
 102
 103 typedef struct
 104 {
 105   GSocket *socket;
 106   GCancellable *cancellable;
 107
 108   void *buffer;
 109   gsize count;
 110
 111   GSocketControlMessage ***messages;
 112   gint *num_messages;
 113
 114   GSimpleAsyncResult *simple;
 115
 116   gboolean from_mainloop;
 117 } ReadWithControlData;
 118
 119 static void
 120 read_with_control_data_free (ReadWithControlData *data)
 121 {
 122   g_object_unref (data->socket);
 123   if (data->cancellable != NULL)
 124     g_object_unref (data->cancellable);
 125   g_object_unref (data->simple);
 126   g_free (data);
 127 }
 128
 129 static gboolean
 130 _g_socket_read_with_control_messages_ready (GSocket      *socket,
 131                                             GIOCondition  condition,
 132                                             gpointer      user_data)
 133 {
 134   ReadWithControlData *data = user_data;
 135   GError *error;
 136   gssize result;
 137   GInputVector vector;
 138
 139   error = NULL;
 140   vector.buffer = data->buffer;
 141   vector.size = data->count;
 142   result = g_socket_receive_message (data->socket,
 143                                      NULL, /* address */
 144                                      &vector,
 145                                      1,
 146                                      data->messages,
 147                                      data->num_messages,
 148                                      NULL,
 149                                      data->cancellable,
 150                                      &error);
 151   if (result >= 0)
 152     {
 153       g_simple_async_result_set_op_res_gssize (data->simple, result);
 154     }
 155   else
 156     {
 157       g_assert (error != NULL);
 158       g_simple_async_result_take_error (data->simple, error);
 159     }
 160
 161   if (data->from_mainloop)
 162     g_simple_async_result_complete (data->simple);
 163   else
 164     g_simple_async_result_complete_in_idle (data->simple);
 165
 166   return FALSE;
 167 }
 168
 169 static void
 170 _g_socket_read_with_control_messages (GSocket                 *socket,
 171                                       void                    *buffer,
 172                                       gsize                    count,
 173                                       GSocketControlMessage ***messages,
 174                                       gint                    *num_messages,
 175                                       gint                     io_priority,
 176                                       GCancellable            *cancellable,
 177                                       GAsyncReadyCallback      callback,
 178                                       gpointer                 user_data)
 179 {
 180   ReadWithControlData *data;
 181
 182   data = g_new0 (ReadWithControlData, 1);
 183   data->socket = g_object_ref (socket);
 184   data->cancellable = cancellable != NULL ? g_object_ref (cancellable) : NULL;
 185   data->buffer = buffer;
 186   data->count = count;
 187   data->messages = messages;
 188   data->num_messages = num_messages;
 189
 190   data->simple = g_simple_async_result_new (G_OBJECT (socket),
 191                                             callback,
 192                                             user_data,
 193                                             _g_socket_read_with_control_messages);
 194
 195   if (!g_socket_condition_check (socket, G_IO_IN))
 196     {
 197       GSource *source;
 198       data->from_mainloop = TRUE;
 199       source = g_socket_create_source (data->socket,
 200                                        G_IO_IN | G_IO_HUP | G_IO_ERR,
 201                                        cancellable);
 202       g_source_set_callback (source,
 203                              (GSourceFunc) _g_socket_read_with_control_messages_ready,
 204                              data,
 205                              (GDestroyNotify) read_with_control_data_free);
 206       g_source_attach (source, g_main_context_get_thread_default ());
 207       g_source_unref (source);
 208     }
 209   else
 210     {
 211       _g_socket_read_with_control_messages_ready (data->socket, G_IO_IN, data);
 212       read_with_control_data_free (data);
 213     }
 214 }
 215
 216 static gssize
 217 _g_socket_read_with_control_messages_finish (GSocket       *socket,
 218                                              GAsyncResult  *result,
 219                                              GError       **error)
 220 {
 221   GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 222
 223   g_return_val_if_fail (G_IS_SOCKET (socket), -1);
 224   g_warn_if_fail (g_simple_async_result_get_source_tag (simple) == _g_socket_read_with_control_messages);
 225
 226   if (g_simple_async_result_propagate_error (simple, error))
 227       return -1;
 228   else
 229     return g_simple_async_result_get_op_res_gssize (simple);
 230 }
 231
 232 /* ---------------------------------------------------------------------------------------------------- */
 233
 234 /* Work-around for https://bugzilla.gnome.org/show_bug.cgi?id=627724 */
 235
 236 static GPtrArray *ensured_classes = NULL;
 237
 238 static void
 239 ensure_type (GType gtype)
 240 {
 241   g_ptr_array_add (ensured_classes, g_type_class_ref (gtype));
 242 }
 243
 244 static void
 245 release_required_types (void)
 246 {
 247   g_ptr_array_foreach (ensured_classes, (GFunc) g_type_class_unref, NULL);
 248   g_ptr_array_unref (ensured_classes);
 249   ensured_classes = NULL;
 250 }
 251
 252 static void
 253 ensure_required_types (void)
 254 {
 255   g_assert (ensured_classes == NULL);
 256   ensured_classes = g_ptr_array_new ();
 257   ensure_type (G_TYPE_SIMPLE_ASYNC_RESULT);
 258   ensure_type (G_TYPE_MEMORY_INPUT_STREAM);
 259 }
 260 /* ---------------------------------------------------------------------------------------------------- */
 261
 262 typedef struct
 263 {
 264   volatile gint refcount;
 265   GThread *thread;
 266   GMainContext *context;
 267   GMainLoop *loop;
 268 } SharedThreadData;
 269
 270 static gpointer
 271 gdbus_shared_thread_func (gpointer user_data)
 272 {
 273   SharedThreadData *data = user_data;
 274
 275   g_main_context_push_thread_default (data->context);
 276   g_main_loop_run (data->loop);
 277   g_main_context_pop_thread_default (data->context);
 278
 279   release_required_types ();
 280
 281   return NULL;
 282 }
 283
 284 /* ---------------------------------------------------------------------------------------------------- */
 285
 286 static SharedThreadData *
 287 _g_dbus_shared_thread_ref (void)
 288 {
 289   static gsize shared_thread_data = 0;
 290   SharedThreadData *ret;
 291
 292   if (g_once_init_enter (&shared_thread_data))
 293     {
 294       SharedThreadData *data;
 295
 296       /* Work-around for https://bugzilla.gnome.org/show_bug.cgi?id=627724 */
 297       ensure_required_types ();
 298
 299       data = g_new0 (SharedThreadData, 1);
 300       data->refcount = 0;
 301
 302       data->context = g_main_context_new ();
 303       data->loop = g_main_loop_new (data->context, FALSE);
 304       data->thread = g_thread_new ("gdbus",
 305                                    gdbus_shared_thread_func,
 306                                    data);
 307       /* We can cast between gsize and gpointer safely */
 308       g_once_init_leave (&shared_thread_data, (gsize) data);
 309     }
 310
 311   ret = (SharedThreadData*) shared_thread_data;
 312   g_atomic_int_inc (&ret->refcount);
 313   return ret;
 314 }
 315
 316 static void
 317 _g_dbus_shared_thread_unref (SharedThreadData *data)
 318 {
 319   /* TODO: actually destroy the shared thread here */
 320 #if 0
 321   g_assert (data != NULL);
 322   if (g_atomic_int_dec_and_test (&data->refcount))
 323     {
 324       g_main_loop_quit (data->loop);
 325       //g_thread_join (data->thread);
 326       g_main_loop_unref (data->loop);
 327       g_main_context_unref (data->context);
 328     }
 329 #endif
 330 }
 331
 332 /* ---------------------------------------------------------------------------------------------------- */
 333
 334 struct GDBusWorker
 335 {
 336   volatile gint                       ref_count;
 337
 338   SharedThreadData                   *shared_thread_data;
 339
 340   /* really a boolean, but GLib 2.28 lacks atomic boolean ops */
 341   volatile gint                       stopped;
 342
 343   /* TODO: frozen (e.g. G_DBUS_CONNECTION_FLAGS_DELAY_MESSAGE_PROCESSING) currently
 344    * only affects messages received from the other peer (since GDBusServer is the
 345    * only user) - we might want it to affect messages sent to the other peer too?
 346    */
 347   gboolean                            frozen;
 348   GDBusCapabilityFlags                capabilities;
 349   GQueue                             *received_messages_while_frozen;
 350
 351   GIOStream                          *stream;
 352   GCancellable                       *cancellable;
 353   GDBusWorkerMessageReceivedCallback  message_received_callback;
 354   GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback;
 355   GDBusWorkerDisconnectedCallback     disconnected_callback;
 356   gpointer                            user_data;
 357
 358   /* if not NULL, stream is GSocketConnection */
 359   GSocket *socket;
 360
 361   /* used for reading */
 362   GMutex                              read_lock;
 363   gchar                              *read_buffer;
 364   gsize                               read_buffer_allocated_size;
 365   gsize                               read_buffer_cur_size;
 366   gsize                               read_buffer_bytes_wanted;
 367   GUnixFDList                        *read_fd_list;
 368   GSocketControlMessage             **read_ancillary_messages;
 369   gint                                read_num_ancillary_messages;
 370
 371   /* TRUE if an async write, flush or close is pending.
 372    * Only the worker thread may change its value, and only with the write_lock.
 373    * Other threads may read its value when holding the write_lock.
 374    * The worker thread may read its value at any time.
 375    */
 376   gboolean                            output_pending;
 377   /* used for writing */
 378   GMutex                              write_lock;
 379   /* queue of MessageToWriteData, protected by write_lock */
 380   GQueue                             *write_queue;
 381   /* protected by write_lock */
 382   guint64                             write_num_messages_written;
 383   /* list of FlushData, protected by write_lock */
 384   GList                              *write_pending_flushes;
 385   /* list of CloseData, protected by write_lock */
 386   GList                              *pending_close_attempts;
 387 };
 388
 389 static void _g_dbus_worker_unref (GDBusWorker *worker);
 390
 391 /* ---------------------------------------------------------------------------------------------------- */
 392
 393 typedef struct
 394 {
 395   GMutex  mutex;
 396   GCond   cond;
 397   guint64 number_to_wait_for;
 398   GError *error;
 399 } FlushData;
 400
 401 struct _MessageToWriteData ;
 402 typedef struct _MessageToWriteData MessageToWriteData;
 403
 404 static void message_to_write_data_free (MessageToWriteData *data);
 405
 406 static void read_message_print_transport_debug (gssize bytes_read,
 407                                                 GDBusWorker *worker);
 408
 409 static void write_message_print_transport_debug (gssize bytes_written,
 410                                                  MessageToWriteData *data);
 411
 412 typedef struct {
 413     GDBusWorker *worker;
 414     GCancellable *cancellable;
 415     GSimpleAsyncResult *result;
 416 } CloseData;
 417
 418 static void close_data_free (CloseData *close_data)
 419 {
 420   if (close_data->cancellable != NULL)
 421     g_object_unref (close_data->cancellable);
 422
 423   if (close_data->result != NULL)
 424     g_object_unref (close_data->result);
 425
 426   _g_dbus_worker_unref (close_data->worker);
 427   g_slice_free (CloseData, close_data);
 428 }
 429
 430 /* ---------------------------------------------------------------------------------------------------- */
 431
 432 static GDBusWorker *
 433 _g_dbus_worker_ref (GDBusWorker *worker)
 434 {
 435   g_atomic_int_inc (&worker->ref_count);
 436   return worker;
 437 }
 438
 439 static void
 440 _g_dbus_worker_unref (GDBusWorker *worker)
 441 {
 442   if (g_atomic_int_dec_and_test (&worker->ref_count))
 443     {
 444       g_assert (worker->write_pending_flushes == NULL);
 445
 446       _g_dbus_shared_thread_unref (worker->shared_thread_data);
 447
 448       g_object_unref (worker->stream);
 449
 450       g_mutex_clear (&worker->read_lock);
 451       g_object_unref (worker->cancellable);
 452       if (worker->read_fd_list != NULL)
 453         g_object_unref (worker->read_fd_list);
 454
 455       g_queue_foreach (worker->received_messages_while_frozen, (GFunc) g_object_unref, NULL);
 456       g_queue_free (worker->received_messages_while_frozen);
 457
 458       g_mutex_clear (&worker->write_lock);
 459       g_queue_foreach (worker->write_queue, (GFunc) message_to_write_data_free, NULL);
 460       g_queue_free (worker->write_queue);
 461
 462       g_free (worker->read_buffer);
 463
 464       g_free (worker);
 465     }
 466 }
 467
 468 static void
 469 _g_dbus_worker_emit_disconnected (GDBusWorker  *worker,
 470                                   gboolean      remote_peer_vanished,
 471                                   GError       *error)
 472 {
 473   if (!g_atomic_int_get (&worker->stopped))
 474     worker->disconnected_callback (worker, remote_peer_vanished, error, worker->user_data);
 475 }
 476
 477 static void
 478 _g_dbus_worker_emit_message_received (GDBusWorker  *worker,
 479                                       GDBusMessage *message)
 480 {
 481   if (!g_atomic_int_get (&worker->stopped))
 482     worker->message_received_callback (worker, message, worker->user_data);
 483 }
 484
 485 static GDBusMessage *
 486 _g_dbus_worker_emit_message_about_to_be_sent (GDBusWorker  *worker,
 487                                               GDBusMessage *message)
 488 {
 489   GDBusMessage *ret;
 490   if (!g_atomic_int_get (&worker->stopped))
 491     ret = worker->message_about_to_be_sent_callback (worker, message, worker->user_data);
 492   else
 493     ret = message;
 494   return ret;
 495 }
 496
 497 /* can only be called from private thread with read-lock held - takes ownership of @message */
 498 static void
 499 _g_dbus_worker_queue_or_deliver_received_message (GDBusWorker  *worker,
 500                                                   GDBusMessage *message)
 501 {
 502   if (worker->frozen || g_queue_get_length (worker->received_messages_while_frozen) > 0)
 503     {
 504       /* queue up */
 505       g_queue_push_tail (worker->received_messages_while_frozen, message);
 506     }
 507   else
 508     {
 509       /* not frozen, nor anything in queue */
 510       _g_dbus_worker_emit_message_received (worker, message);
 511       g_object_unref (message);
 512     }
 513 }
 514
 515 /* called in private thread shared by all GDBusConnection instances (without read-lock held) */
 516 static gboolean
 517 unfreeze_in_idle_cb (gpointer user_data)
 518 {
 519   GDBusWorker *worker = user_data;
 520   GDBusMessage *message;
 521
 522   g_mutex_lock (&worker->read_lock);
 523   if (worker->frozen)
 524     {
 525       while ((message = g_queue_pop_head (worker->received_messages_while_frozen)) != NULL)
 526         {
 527           _g_dbus_worker_emit_message_received (worker, message);
 528           g_object_unref (message);
 529         }
 530       worker->frozen = FALSE;
 531     }
 532   else
 533     {
 534       g_assert (g_queue_get_length (worker->received_messages_while_frozen) == 0);
 535     }
 536   g_mutex_unlock (&worker->read_lock);
 537   return FALSE;
 538 }
 539
 540 /* can be called from any thread */
 541 void
 542 _g_dbus_worker_unfreeze (GDBusWorker *worker)
 543 {
 544   GSource *idle_source;
 545   idle_source = g_idle_source_new ();
 546   g_source_set_priority (idle_source, G_PRIORITY_DEFAULT);
 547   g_source_set_callback (idle_source,
 548                          unfreeze_in_idle_cb,
 549                          _g_dbus_worker_ref (worker),
 550                          (GDestroyNotify) _g_dbus_worker_unref);
 551   g_source_attach (idle_source, worker->shared_thread_data->context);
 552   g_source_unref (idle_source);
 553 }
 554
 555 /* ---------------------------------------------------------------------------------------------------- */
 556
 557 static void _g_dbus_worker_do_read_unlocked (GDBusWorker *worker);
 558
 559 /* called in private thread shared by all GDBusConnection instances (without read-lock held) */
 560 static void
 561 _g_dbus_worker_do_read_cb (GInputStream  *input_stream,
 562                            GAsyncResult  *res,
 563                            gpointer       user_data)
 564 {
 565   GDBusWorker *worker = user_data;
 566   GError *error;
 567   gssize bytes_read;
 568
 569   g_mutex_lock (&worker->read_lock);
 570
 571   /* If already stopped, don't even process the reply */
 572   if (g_atomic_int_get (&worker->stopped))
 573     goto out;
 574
 575   error = NULL;
 576   if (worker->socket == NULL)
 577     bytes_read = g_input_stream_read_finish (g_io_stream_get_input_stream (worker->stream),
 578                                              res,
 579                                              &error);
 580   else
 581     bytes_read = _g_socket_read_with_control_messages_finish (worker->socket,
 582                                                               res,
 583                                                               &error);
 584   if (worker->read_num_ancillary_messages > 0)
 585     {
 586       gint n;
 587       for (n = 0; n < worker->read_num_ancillary_messages; n++)
 588         {
 589           GSocketControlMessage *control_message = G_SOCKET_CONTROL_MESSAGE (worker->read_ancillary_messages[n]);
 590
 591           if (FALSE)
 592             {
 593             }
 594 #ifdef G_OS_UNIX
 595           else if (G_IS_UNIX_FD_MESSAGE (control_message))
 596             {
 597               GUnixFDMessage *fd_message;
 598               gint *fds;
 599               gint num_fds;
 600
 601               fd_message = G_UNIX_FD_MESSAGE (control_message);
 602               fds = g_unix_fd_message_steal_fds (fd_message, &num_fds);
 603               if (worker->read_fd_list == NULL)
 604                 {
 605                   worker->read_fd_list = g_unix_fd_list_new_from_array (fds, num_fds);
 606                 }
 607               else
 608                 {
 609                   gint n;
 610                   for (n = 0; n < num_fds; n++)
 611                     {
 612                       /* TODO: really want a append_steal() */
 613                       g_unix_fd_list_append (worker->read_fd_list, fds[n], NULL);
 614                       close (fds[n]);
 615                     }
 616                 }
 617               g_free (fds);
 618             }
 619           else if (G_IS_UNIX_CREDENTIALS_MESSAGE (control_message))
 620             {
 621               /* do nothing */
 622             }
 623 #endif
 624           else
 625             {
 626               if (error == NULL)
 627                 {
 628                   g_set_error (&error,
 629                                G_IO_ERROR,
 630                                G_IO_ERROR_FAILED,
 631                                "Unexpected ancillary message of type %s received from peer",
 632                                g_type_name (G_TYPE_FROM_INSTANCE (control_message)));
 633                   _g_dbus_worker_emit_disconnected (worker, TRUE, error);
 634                   g_error_free (error);
 635                   g_object_unref (control_message);
 636                   n++;
 637                   while (n < worker->read_num_ancillary_messages)
 638                     g_object_unref (worker->read_ancillary_messages[n++]);
 639                   g_free (worker->read_ancillary_messages);
 640                   goto out;
 641                 }
 642             }
 643           g_object_unref (control_message);
 644         }
 645       g_free (worker->read_ancillary_messages);
 646     }
 647
 648   if (bytes_read == -1)
 649     {
 650       if (G_UNLIKELY (_g_dbus_debug_transport ()))
 651         {
 652           _g_dbus_debug_print_lock ();
 653           g_print ("========================================================================\n"
 654                    "GDBus-debug:Transport:\n"
 655                    "  ---- READ ERROR on stream of type %s:\n"
 656                    "  ---- %s %d: %s\n",
 657                    g_type_name (G_TYPE_FROM_INSTANCE (g_io_stream_get_input_stream (worker->stream))),
 658                    g_quark_to_string (error->domain), error->code,
 659                    error->message);
 660           _g_dbus_debug_print_unlock ();
 661         }
 662
 663       /* Every async read that uses this callback uses worker->cancellable
 664        * as its GCancellable. worker->cancellable gets cancelled if and only
 665        * if the GDBusConnection tells us to close (either via
 666        * _g_dbus_worker_stop, which is called on last-unref, or directly),
 667        * so a cancelled read must mean our connection was closed locally.
 668        */
 669       if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
 670         _g_dbus_worker_emit_disconnected (worker, FALSE, NULL);
 671       else
 672         _g_dbus_worker_emit_disconnected (worker, TRUE, error);
 673
 674       g_error_free (error);
 675       goto out;
 676     }
 677
 678 #if 0
 679   g_debug ("read %d bytes (is_closed=%d blocking=%d condition=0x%02x) stream %p, %p",
 680            (gint) bytes_read,
 681            g_socket_is_closed (g_socket_connection_get_socket (G_SOCKET_CONNECTION (worker->stream))),
 682            g_socket_get_blocking (g_socket_connection_get_socket (G_SOCKET_CONNECTION (worker->stream))),
 683            g_socket_condition_check (g_socket_connection_get_socket (G_SOCKET_CONNECTION (worker->stream)),
 684                                      G_IO_IN | G_IO_OUT | G_IO_HUP),
 685            worker->stream,
 686            worker);
 687 #endif
 688
 689   /* TODO: hmm, hmm... */
 690   if (bytes_read == 0)
 691     {
 692       g_set_error (&error,
 693                    G_IO_ERROR,
 694                    G_IO_ERROR_FAILED,
 695                    "Underlying GIOStream returned 0 bytes on an async read");
 696       _g_dbus_worker_emit_disconnected (worker, TRUE, error);
 697       g_error_free (error);
 698       goto out;
 699     }
 700
 701   read_message_print_transport_debug (bytes_read, worker);
 702
 703   worker->read_buffer_cur_size += bytes_read;
 704   if (worker->read_buffer_bytes_wanted == worker->read_buffer_cur_size)
 705     {
 706       /* OK, got what we asked for! */
 707       if (worker->read_buffer_bytes_wanted == 16)
 708         {
 709           gssize message_len;
 710           /* OK, got the header - determine how many more bytes are needed */
 711           error = NULL;
 712           message_len = g_dbus_message_bytes_needed ((guchar *) worker->read_buffer,
 713                                                      16,
 714                                                      &error);
 715           if (message_len == -1)
 716             {
 717               g_warning ("_g_dbus_worker_do_read_cb: error determing bytes needed: %s", error->message);
 718               _g_dbus_worker_emit_disconnected (worker, FALSE, error);
 719               g_error_free (error);
 720               goto out;
 721             }
 722
 723           worker->read_buffer_bytes_wanted = message_len;
 724           _g_dbus_worker_do_read_unlocked (worker);
 725         }
 726       else
 727         {
 728           GDBusMessage *message;
 729           error = NULL;
 730
 731           /* TODO: use connection->priv->auth to decode the message */
 732
 733           message = g_dbus_message_new_from_blob ((guchar *) worker->read_buffer,
 734                                                   worker->read_buffer_cur_size,
 735                                                   worker->capabilities,
 736                                                   &error);
 737           if (message == NULL)
 738             {
 739               gchar *s;
 740               s = _g_dbus_hexdump (worker->read_buffer, worker->read_buffer_cur_size, 2);
 741               g_warning ("Error decoding D-Bus message of %" G_GSIZE_FORMAT " bytes\n"
 742                          "The error is: %s\n"
 743                          "The payload is as follows:\n"
 744                          "%s\n",
 745                          worker->read_buffer_cur_size,
 746                          error->message,
 747                          s);
 748               g_free (s);
 749               _g_dbus_worker_emit_disconnected (worker, FALSE, error);
 750               g_error_free (error);
 751               goto out;
 752             }
 753
 754 #ifdef G_OS_UNIX
 755           if (worker->read_fd_list != NULL)
 756             {
 757               g_dbus_message_set_unix_fd_list (message, worker->read_fd_list);
 758               g_object_unref (worker->read_fd_list);
 759               worker->read_fd_list = NULL;
 760             }
 761 #endif
 762
 763           if (G_UNLIKELY (_g_dbus_debug_message ()))
 764             {
 765               gchar *s;
 766               _g_dbus_debug_print_lock ();
 767               g_print ("========================================================================\n"
 768                        "GDBus-debug:Message:\n"
 769                        "  <<<< RECEIVED D-Bus message (%" G_GSIZE_FORMAT " bytes)\n",
 770                        worker->read_buffer_cur_size);
 771               s = g_dbus_message_print (message, 2);
 772               g_print ("%s", s);
 773               g_free (s);
 774               if (G_UNLIKELY (_g_dbus_debug_payload ()))
 775                 {
 776                   s = _g_dbus_hexdump (worker->read_buffer, worker->read_buffer_cur_size, 2);
 777                   g_print ("%s\n", s);
 778                   g_free (s);
 779                 }
 780               _g_dbus_debug_print_unlock ();
 781             }
 782
 783           /* yay, got a message, go deliver it */
 784           _g_dbus_worker_queue_or_deliver_received_message (worker, message);
 785
 786           /* start reading another message! */
 787           worker->read_buffer_bytes_wanted = 0;
 788           worker->read_buffer_cur_size = 0;
 789           _g_dbus_worker_do_read_unlocked (worker);
 790         }
 791     }
 792   else
 793     {
 794       /* didn't get all the bytes we requested - so repeat the request... */
 795       _g_dbus_worker_do_read_unlocked (worker);
 796     }
 797
 798  out:
 799   g_mutex_unlock (&worker->read_lock);
 800
 801   /* gives up the reference acquired when calling g_input_stream_read_async() */
 802   _g_dbus_worker_unref (worker);
 803 }
 804
 805 /* called in private thread shared by all GDBusConnection instances (with read-lock held) */
 806 static void
 807 _g_dbus_worker_do_read_unlocked (GDBusWorker *worker)
 808 {
 809   /* if bytes_wanted is zero, it means start reading a message */
 810   if (worker->read_buffer_bytes_wanted == 0)
 811     {
 812       worker->read_buffer_cur_size = 0;
 813       worker->read_buffer_bytes_wanted = 16;
 814     }
 815
 816   /* ensure we have a (big enough) buffer */
 817   if (worker->read_buffer == NULL || worker->read_buffer_bytes_wanted > worker->read_buffer_allocated_size)
 818     {
 819       /* TODO: 4096 is randomly chosen; might want a better chosen default minimum */
 820       worker->read_buffer_allocated_size = MAX (worker->read_buffer_bytes_wanted, 4096);
 821       worker->read_buffer = g_realloc (worker->read_buffer, worker->read_buffer_allocated_size);
 822     }
 823
 824   if (worker->socket == NULL)
 825     g_input_stream_read_async (g_io_stream_get_input_stream (worker->stream),
 826                                worker->read_buffer + worker->read_buffer_cur_size,
 827                                worker->read_buffer_bytes_wanted - worker->read_buffer_cur_size,
 828                                G_PRIORITY_DEFAULT,
 829                                worker->cancellable,
 830                                (GAsyncReadyCallback) _g_dbus_worker_do_read_cb,
 831                                _g_dbus_worker_ref (worker));
 832   else
 833     {
 834       worker->read_ancillary_messages = NULL;
 835       worker->read_num_ancillary_messages = 0;
 836       _g_socket_read_with_control_messages (worker->socket,
 837                                             worker->read_buffer + worker->read_buffer_cur_size,
 838                                             worker->read_buffer_bytes_wanted - worker->read_buffer_cur_size,
 839                                             &worker->read_ancillary_messages,
 840                                             &worker->read_num_ancillary_messages,
 841                                             G_PRIORITY_DEFAULT,
 842                                             worker->cancellable,
 843                                             (GAsyncReadyCallback) _g_dbus_worker_do_read_cb,
 844                                             _g_dbus_worker_ref (worker));
 845     }
 846 }
 847
 848 /* called in private thread shared by all GDBusConnection instances (without read-lock held) */
 849 static gboolean
 850 _g_dbus_worker_do_initial_read (gpointer data)
 851 {
 852   GDBusWorker *worker = data;
 853   g_mutex_lock (&worker->read_lock);
 854   _g_dbus_worker_do_read_unlocked (worker);
 855   g_mutex_unlock (&worker->read_lock);
 856   return FALSE;
 857 }
 858
 859 /* ---------------------------------------------------------------------------------------------------- */
 860
 861 struct _MessageToWriteData
 862 {
 863   GDBusWorker  *worker;
 864   GDBusMessage *message;
 865   gchar        *blob;
 866   gsize         blob_size;
 867
 868   gsize               total_written;
 869   GSimpleAsyncResult *simple;
 870
 871 };
 872
 873 static void
 874 message_to_write_data_free (MessageToWriteData *data)
 875 {
 876   _g_dbus_worker_unref (data->worker);
 877   if (data->message)
 878     g_object_unref (data->message);
 879   g_free (data->blob);
 880   g_free (data);
 881 }
 882
 883 /* ---------------------------------------------------------------------------------------------------- */
 884
 885 static void write_message_continue_writing (MessageToWriteData *data);
 886
 887 /* called in private thread shared by all GDBusConnection instances
 888  *
 889  * write-lock is not held on entry
 890  * output_pending is true on entry
 891  */
 892 static void
 893 write_message_async_cb (GObject      *source_object,
 894                         GAsyncResult *res,
 895                         gpointer      user_data)
 896 {
 897   MessageToWriteData *data = user_data;
 898   GSimpleAsyncResult *simple;
 899   gssize bytes_written;
 900   GError *error;
 901
 902   /* Note: we can't access data->simple after calling g_async_result_complete () because the
 903    * callback can free @data and we're not completing in idle. So use a copy of the pointer.
 904    */
 905   simple = data->simple;
 906
 907   error = NULL;
 908   bytes_written = g_output_stream_write_finish (G_OUTPUT_STREAM (source_object),
 909                                                 res,
 910                                                 &error);
 911   if (bytes_written == -1)
 912     {
 913       g_simple_async_result_take_error (simple, error);
 914       g_simple_async_result_complete (simple);
 915       g_object_unref (simple);
 916       goto out;
 917     }
 918   g_assert (bytes_written > 0); /* zero is never returned */
 919
 920   write_message_print_transport_debug (bytes_written, data);
 921
 922   data->total_written += bytes_written;
 923   g_assert (data->total_written <= data->blob_size);
 924   if (data->total_written == data->blob_size)
 925     {
 926       g_simple_async_result_complete (simple);
 927       g_object_unref (simple);
 928       goto out;
 929     }
 930
 931   write_message_continue_writing (data);
 932
 933  out:
 934   ;
 935 }
 936
 937 /* called in private thread shared by all GDBusConnection instances
 938  *
 939  * write-lock is not held on entry
 940  * output_pending is true on entry
 941  */
 942 static gboolean
 943 on_socket_ready (GSocket      *socket,
 944                  GIOCondition  condition,
 945                  gpointer      user_data)
 946 {
 947   MessageToWriteData *data = user_data;
 948   write_message_continue_writing (data);
 949   return FALSE; /* remove source */
 950 }
 951
 952 /* called in private thread shared by all GDBusConnection instances
 953  *
 954  * write-lock is not held on entry
 955  * output_pending is true on entry
 956  */
 957 static void
 958 write_message_continue_writing (MessageToWriteData *data)
 959 {
 960   GOutputStream *ostream;
 961   GSimpleAsyncResult *simple;
 962 #ifdef G_OS_UNIX
 963   GUnixFDList *fd_list;
 964 #endif
 965
 966   /* Note: we can't access data->simple after calling g_async_result_complete () because the
 967    * callback can free @data and we're not completing in idle. So use a copy of the pointer.
 968    */
 969   simple = data->simple;
 970
 971   ostream = g_io_stream_get_output_stream (data->worker->stream);
 972 #ifdef G_OS_UNIX
 973   fd_list = g_dbus_message_get_unix_fd_list (data->message);
 974 #endif
 975
 976   g_assert (!g_output_stream_has_pending (ostream));
 977   g_assert_cmpint (data->total_written, <, data->blob_size);
 978
 979   if (FALSE)
 980     {
 981     }
 982 #ifdef G_OS_UNIX
 983   else if (G_IS_SOCKET_OUTPUT_STREAM (ostream) && data->total_written == 0)
 984     {
 985       GOutputVector vector;
 986       GSocketControlMessage *control_message;
 987       gssize bytes_written;
 988       GError *error;
 989
 990       vector.buffer = data->blob;
 991       vector.size = data->blob_size;
 992
 993       control_message = NULL;
 994       if (fd_list != NULL && g_unix_fd_list_get_length (fd_list) > 0)
 995         {
 996           if (!(data->worker->capabilities & G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING))
 997             {
 998               g_simple_async_result_set_error (simple,
 999                                                G_IO_ERROR,
1000                                                G_IO_ERROR_FAILED,
1001                                                "Tried sending a file descriptor but remote peer does not support this capability");
1002               g_simple_async_result_complete (simple);
1003               g_object_unref (simple);
1004               goto out;
1005             }
1006           control_message = g_unix_fd_message_new_with_fd_list (fd_list);
1007         }
1008
1009       error = NULL;
1010       bytes_written = g_socket_send_message (data->worker->socket,
1011                                              NULL, /* address */
1012                                              &vector,
1013                                              1,
1014                                              control_message != NULL ? &control_message : NULL,
1015                                              control_message != NULL ? 1 : 0,
1016                                              G_SOCKET_MSG_NONE,
1017                                              data->worker->cancellable,
1018                                              &error);
1019       if (control_message != NULL)
1020         g_object_unref (control_message);
1021
1022       if (bytes_written == -1)
1023         {
1024           /* Handle WOULD_BLOCK by waiting until there's room in the buffer */
1025           if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_WOULD_BLOCK))
1026             {
1027               GSource *source;
1028               source = g_socket_create_source (data->worker->socket,
1029                                                G_IO_OUT | G_IO_HUP | G_IO_ERR,
1030                                                data->worker->cancellable);
1031               g_source_set_callback (source,
1032                                      (GSourceFunc) on_socket_ready,
1033                                      data,
1034                                      NULL); /* GDestroyNotify */
1035               g_source_attach (source, g_main_context_get_thread_default ());
1036               g_source_unref (source);
1037               g_error_free (error);
1038               goto out;
1039             }
1040           g_simple_async_result_take_error (simple, error);
1041           g_simple_async_result_complete (simple);
1042           g_object_unref (simple);
1043           goto out;
1044         }
1045       g_assert (bytes_written > 0); /* zero is never returned */
1046
1047       write_message_print_transport_debug (bytes_written, data);
1048
1049       data->total_written += bytes_written;
1050       g_assert (data->total_written <= data->blob_size);
1051       if (data->total_written == data->blob_size)
1052         {
1053           g_simple_async_result_complete (simple);
1054           g_object_unref (simple);
1055           goto out;
1056         }
1057
1058       write_message_continue_writing (data);
1059     }
1060 #endif
1061   else
1062     {
1063 #ifdef G_OS_UNIX
1064       if (fd_list != NULL)
1065         {
1066           g_simple_async_result_set_error (simple,
1067                                            G_IO_ERROR,
1068                                            G_IO_ERROR_FAILED,
1069                                            "Tried sending a file descriptor on unsupported stream of type %s",
1070                                            g_type_name (G_TYPE_FROM_INSTANCE (ostream)));
1071           g_simple_async_result_complete (simple);
1072           g_object_unref (simple);
1073           goto out;
1074         }
1075 #endif
1076
1077       g_output_stream_write_async (ostream,
1078                                    (const gchar *) data->blob + data->total_written,
1079                                    data->blob_size - data->total_written,
1080                                    G_PRIORITY_DEFAULT,
1081                                    data->worker->cancellable,
1082                                    write_message_async_cb,
1083                                    data);
1084     }
1085  out:
1086   ;
1087 }
1088
1089 /* called in private thread shared by all GDBusConnection instances
1090  *
1091  * write-lock is not held on entry
1092  * output_pending is true on entry
1093  */
1094 static void
1095 write_message_async (GDBusWorker         *worker,
1096                      MessageToWriteData  *data,
1097                      GAsyncReadyCallback  callback,
1098                      gpointer             user_data)
1099 {
1100   data->simple = g_simple_async_result_new (NULL,
1101                                             callback,
1102                                             user_data,
1103                                             write_message_async);
1104   data->total_written = 0;
1105   write_message_continue_writing (data);
1106 }
1107
1108 /* called in private thread shared by all GDBusConnection instances (without write-lock held) */
1109 static gboolean
1110 write_message_finish (GAsyncResult   *res,
1111                       GError        **error)
1112 {
1113   g_warn_if_fail (g_simple_async_result_get_source_tag (G_SIMPLE_ASYNC_RESULT (res)) == write_message_async);
1114   if (g_simple_async_result_propagate_error (G_SIMPLE_ASYNC_RESULT (res), error))
1115     return FALSE;
1116   else
1117     return TRUE;
1118 }
1119 /* ---------------------------------------------------------------------------------------------------- */
1120
1121 static void maybe_write_next_message (GDBusWorker *worker);
1122
1123 typedef struct
1124 {
1125   GDBusWorker *worker;
1126   GList *flushers;
1127 } FlushAsyncData;
1128
1129 static void
1130 flush_data_list_complete (const GList  *flushers,
1131                           const GError *error)
1132 {
1133   const GList *l;
1134
1135   for (l = flushers; l != NULL; l = l->next)
1136     {
1137       FlushData *f = l->data;
1138
1139       f->error = error != NULL ? g_error_copy (error) : NULL;
1140
1141       g_mutex_lock (&f->mutex);
1142       g_cond_signal (&f->cond);
1143       g_mutex_unlock (&f->mutex);
1144     }
1145 }
1146
1147 /* called in private thread shared by all GDBusConnection instances
1148  *
1149  * write-lock is not held on entry
1150  * output_pending is true on entry
1151  */
1152 static void
1153 ostream_flush_cb (GObject      *source_object,
1154                   GAsyncResult *res,
1155                   gpointer      user_data)
1156 {
1157   FlushAsyncData *data = user_data;
1158   GError *error;
1159
1160   error = NULL;
1161   g_output_stream_flush_finish (G_OUTPUT_STREAM (source_object),
1162                                 res,
1163                                 &error);
1164
1165   if (error == NULL)
1166     {
1167       if (G_UNLIKELY (_g_dbus_debug_transport ()))
1168         {
1169           _g_dbus_debug_print_lock ();
1170           g_print ("========================================================================\n"
1171                    "GDBus-debug:Transport:\n"
1172                    "  ---- FLUSHED stream of type %s\n",
1173                    g_type_name (G_TYPE_FROM_INSTANCE (g_io_stream_get_output_stream (data->worker->stream))));
1174           _g_dbus_debug_print_unlock ();
1175         }
1176     }
1177
1178   g_assert (data->flushers != NULL);
1179   flush_data_list_complete (data->flushers, error);
1180   g_list_free (data->flushers);
1181
1182   if (error != NULL)
1183     g_error_free (error);
1184
1185   /* Make sure we tell folks that we don't have additional
1186      flushes pending */
1187   g_mutex_lock (&data->worker->write_lock);
1188   g_assert (data->worker->output_pending);
1189   data->worker->output_pending = FALSE;
1190   g_mutex_unlock (&data->worker->write_lock);
1191
1192   /* OK, cool, finally kick off the next write */
1193   maybe_write_next_message (data->worker);
1194
1195   _g_dbus_worker_unref (data->worker);
1196   g_free (data);
1197 }
1198
1199 /* called in private thread shared by all GDBusConnection instances
1200  *
1201  * write-lock is not held on entry
1202  * output_pending is false on entry
1203  */
1204 static void
1205 message_written (GDBusWorker *worker,
1206                  MessageToWriteData *message_data)
1207 {
1208   GList *l;
1209   GList *ll;
1210   GList *flushers;
1211
1212   /* first log the fact that we wrote a message */
1213   if (G_UNLIKELY (_g_dbus_debug_message ()))
1214     {
1215       gchar *s;
1216       _g_dbus_debug_print_lock ();
1217       g_print ("========================================================================\n"
1218                "GDBus-debug:Message:\n"
1219                "  >>>> SENT D-Bus message (%" G_GSIZE_FORMAT " bytes)\n",
1220                message_data->blob_size);
1221       s = g_dbus_message_print (message_data->message, 2);
1222       g_print ("%s", s);
1223       g_free (s);
1224       if (G_UNLIKELY (_g_dbus_debug_payload ()))
1225         {
1226           s = _g_dbus_hexdump (message_data->blob, message_data->blob_size, 2);
1227           g_print ("%s\n", s);
1228           g_free (s);
1229         }
1230       _g_dbus_debug_print_unlock ();
1231     }
1232
1233   /* then first wake up pending flushes and, if needed, flush the stream */
1234   flushers = NULL;
1235   g_mutex_lock (&worker->write_lock);
1236   worker->write_num_messages_written += 1;
1237   for (l = worker->write_pending_flushes; l != NULL; l = ll)
1238     {
1239       FlushData *f = l->data;
1240       ll = l->next;
1241
1242       if (f->number_to_wait_for == worker->write_num_messages_written)
1243         {
1244           flushers = g_list_append (flushers, f);
1245           worker->write_pending_flushes = g_list_delete_link (worker->write_pending_flushes, l);
1246         }
1247     }
1248   if (flushers != NULL)
1249     {
1250       g_assert (!worker->output_pending);
1251       worker->output_pending = TRUE;
1252     }
1253   g_mutex_unlock (&worker->write_lock);
1254
1255   if (flushers != NULL)
1256     {
1257       FlushAsyncData *data;
1258       data = g_new0 (FlushAsyncData, 1);
1259       data->worker = _g_dbus_worker_ref (worker);
1260       data->flushers = flushers;
1261       /* flush the stream before writing the next message */
1262       g_output_stream_flush_async (g_io_stream_get_output_stream (worker->stream),
1263                                    G_PRIORITY_DEFAULT,
1264                                    worker->cancellable,
1265                                    ostream_flush_cb,
1266                                    data);
1267     }
1268   else
1269     {
1270       /* kick off the next write! */
1271       maybe_write_next_message (worker);
1272     }
1273 }
1274
1275 /* called in private thread shared by all GDBusConnection instances
1276  *
1277  * write-lock is not held on entry
1278  * output_pending is true on entry
1279  */
1280 static void
1281 write_message_cb (GObject       *source_object,
1282                   GAsyncResult  *res,
1283                   gpointer       user_data)
1284 {
1285   MessageToWriteData *data = user_data;
1286   GError *error;
1287
1288   g_mutex_lock (&data->worker->write_lock);
1289   g_assert (data->worker->output_pending);
1290   data->worker->output_pending = FALSE;
1291   g_mutex_unlock (&data->worker->write_lock);
1292
1293   error = NULL;
1294   if (!write_message_finish (res, &error))
1295     {
1296       /* TODO: handle */
1297       _g_dbus_worker_emit_disconnected (data->worker, TRUE, error);
1298       g_error_free (error);
1299     }
1300
1301   /* this function will also kick of the next write (it might need to
1302    * flush so writing the next message might happen much later
1303    * e.g. async)
1304    */
1305   message_written (data->worker, data);
1306
1307   message_to_write_data_free (data);
1308 }
1309
1310 /* called in private thread shared by all GDBusConnection instances
1311  *
1312  * write-lock is not held on entry
1313  * output_pending is true on entry
1314  */
1315 static void
1316 iostream_close_cb (GObject      *source_object,
1317                    GAsyncResult *res,
1318                    gpointer      user_data)
1319 {
1320   GDBusWorker *worker = user_data;
1321   GError *error = NULL;
1322   GList *pending_close_attempts, *pending_flush_attempts;
1323   GQueue *send_queue;
1324
1325   g_io_stream_close_finish (worker->stream, res, &error);
1326
1327   g_mutex_lock (&worker->write_lock);
1328
1329   pending_close_attempts = worker->pending_close_attempts;
1330   worker->pending_close_attempts = NULL;
1331
1332   pending_flush_attempts = worker->write_pending_flushes;
1333   worker->write_pending_flushes = NULL;
1334
1335   send_queue = worker->write_queue;
1336   worker->write_queue = g_queue_new ();
1337
1338   g_assert (worker->output_pending);
1339   worker->output_pending = FALSE;
1340
1341   g_mutex_unlock (&worker->write_lock);
1342
1343   while (pending_close_attempts != NULL)
1344     {
1345       CloseData *close_data = pending_close_attempts->data;
1346
1347       pending_close_attempts = g_list_delete_link (pending_close_attempts,
1348                                                    pending_close_attempts);
1349
1350       if (close_data->result != NULL)
1351         {
1352           if (error != NULL)
1353             g_simple_async_result_set_from_error (close_data->result, error);
1354
1355           /* this must be in an idle because the result is likely to be
1356            * intended for another thread
1357            */
1358           g_simple_async_result_complete_in_idle (close_data->result);
1359         }
1360
1361       close_data_free (close_data);
1362     }
1363
1364   g_clear_error (&error);
1365
1366   /* all messages queued for sending are discarded */
1367   g_queue_foreach (send_queue, (GFunc) message_to_write_data_free, NULL);
1368   g_queue_free (send_queue);
1369
1370   /* all queued flushes fail */
1371   error = g_error_new (G_IO_ERROR, G_IO_ERROR_CANCELLED,
1372                        _("Operation was cancelled"));
1373   flush_data_list_complete (pending_flush_attempts, error);
1374   g_list_free (pending_flush_attempts);
1375   g_clear_error (&error);
1376
1377   _g_dbus_worker_unref (worker);
1378 }
1379
1380 /* called in private thread shared by all GDBusConnection instances
1381  *
1382  * write-lock is not held on entry
1383  * output_pending must be false on entry
1384  */
1385 static void
1386 maybe_write_next_message (GDBusWorker *worker)
1387 {
1388   MessageToWriteData *data;
1389
1390  write_next:
1391   /* we mustn't try to write two things at once */
1392   g_assert (!worker->output_pending);
1393
1394   g_mutex_lock (&worker->write_lock);
1395
1396   /* if we want to close the connection, that takes precedence */
1397   if (worker->pending_close_attempts != NULL)
1398     {
1399       worker->output_pending = TRUE;
1400
1401       g_io_stream_close_async (worker->stream, G_PRIORITY_DEFAULT,
1402                                NULL, iostream_close_cb,
1403                                _g_dbus_worker_ref (worker));
1404       data = NULL;
1405     }
1406   else
1407     {
1408       data = g_queue_pop_head (worker->write_queue);
1409
1410       if (data != NULL)
1411         worker->output_pending = TRUE;
1412     }
1413
1414   g_mutex_unlock (&worker->write_lock);
1415
1416   /* Note that write_lock is only used for protecting the @write_queue
1417    * and @output_pending fields of the GDBusWorker struct ... which we
1418    * need to modify from arbitrary threads in _g_dbus_worker_send_message().
1419    *
1420    * Therefore, it's fine to drop it here when calling back into user
1421    * code and then writing the message out onto the GIOStream since this
1422    * function only runs on the worker thread.
1423    */
1424   if (data != NULL)
1425     {
1426       GDBusMessage *old_message;
1427       guchar *new_blob;
1428       gsize new_blob_size;
1429       GError *error;
1430
1431       old_message = data->message;
1432       data->message = _g_dbus_worker_emit_message_about_to_be_sent (worker, data->message);
1433       if (data->message == old_message)
1434         {
1435           /* filters had no effect - do nothing */
1436         }
1437       else if (data->message == NULL)
1438         {
1439           /* filters dropped message */
1440           g_mutex_lock (&worker->write_lock);
1441           worker->output_pending = FALSE;
1442           g_mutex_unlock (&worker->write_lock);
1443           message_to_write_data_free (data);
1444           goto write_next;
1445         }
1446       else
1447         {
1448           /* filters altered the message -> reencode */
1449           error = NULL;
1450           new_blob = g_dbus_message_to_blob (data->message,
1451                                              &new_blob_size,
1452                                              worker->capabilities,
1453                                              &error);
1454           if (new_blob == NULL)
1455             {
1456               /* if filter make the GDBusMessage unencodeable, just complain on stderr and send
1457                * the old message instead
1458                */
1459               g_warning ("Error encoding GDBusMessage with serial %d altered by filter function: %s",
1460                          g_dbus_message_get_serial (data->message),
1461                          error->message);
1462               g_error_free (error);
1463             }
1464           else
1465             {
1466               g_free (data->blob);
1467               data->blob = (gchar *) new_blob;
1468               data->blob_size = new_blob_size;
1469             }
1470         }
1471
1472       write_message_async (worker,
1473                            data,
1474                            write_message_cb,
1475                            data);
1476     }
1477 }
1478
1479 /* called in private thread shared by all GDBusConnection instances
1480  *
1481  * write-lock is not held on entry
1482  * output_pending may be true or false
1483  */
1484 static gboolean
1485 write_message_in_idle_cb (gpointer user_data)
1486 {
1487   GDBusWorker *worker = user_data;
1488
1489   /* Because this is the worker thread, we can read this struct member
1490    * without holding the lock: no other thread ever modifies it.
1491    */
1492   if (!worker->output_pending)
1493     maybe_write_next_message (worker);
1494
1495   return FALSE;
1496 }
1497
1498 /*
1499  * @write_data: (transfer full) (allow-none):
1500  * @close_data: (transfer full) (allow-none):
1501  *
1502  * Can be called from any thread
1503  *
1504  * write_lock is not held on entry
1505  * output_pending may be true or false
1506  */
1507 static void
1508 schedule_write_in_worker_thread (GDBusWorker        *worker,
1509                                  MessageToWriteData *write_data,
1510                                  CloseData          *close_data)
1511 {
1512   g_mutex_lock (&worker->write_lock);
1513
1514   if (write_data != NULL)
1515     g_queue_push_tail (worker->write_queue, write_data);
1516
1517   if (close_data != NULL)
1518     worker->pending_close_attempts = g_list_prepend (worker->pending_close_attempts,
1519                                                      close_data);
1520
1521   if (!worker->output_pending)
1522     {
1523       GSource *idle_source;
1524       idle_source = g_idle_source_new ();
1525       g_source_set_priority (idle_source, G_PRIORITY_DEFAULT);
1526       g_source_set_callback (idle_source,
1527                              write_message_in_idle_cb,
1528                              _g_dbus_worker_ref (worker),
1529                              (GDestroyNotify) _g_dbus_worker_unref);
1530       g_source_attach (idle_source, worker->shared_thread_data->context);
1531       g_source_unref (idle_source);
1532     }
1533
1534   g_mutex_unlock (&worker->write_lock);
1535 }
1536
1537 /* ---------------------------------------------------------------------------------------------------- */
1538
1539 /* can be called from any thread - steals blob
1540  *
1541  * write_lock is not held on entry
1542  * output_pending may be true or false
1543  */
1544 void
1545 _g_dbus_worker_send_message (GDBusWorker    *worker,
1546                              GDBusMessage   *message,
1547                              gchar          *blob,
1548                              gsize           blob_len)
1549 {
1550   MessageToWriteData *data;
1551
1552   g_return_if_fail (G_IS_DBUS_MESSAGE (message));
1553   g_return_if_fail (blob != NULL);
1554   g_return_if_fail (blob_len > 16);
1555
1556   data = g_new0 (MessageToWriteData, 1);
1557   data->worker = _g_dbus_worker_ref (worker);
1558   data->message = g_object_ref (message);
1559   data->blob = blob; /* steal! */
1560   data->blob_size = blob_len;
1561
1562   schedule_write_in_worker_thread (worker, data, NULL);
1563 }
1564
1565 /* ---------------------------------------------------------------------------------------------------- */
1566
1567 GDBusWorker *
1568 _g_dbus_worker_new (GIOStream                              *stream,
1569                     GDBusCapabilityFlags                    capabilities,
1570                     gboolean                                initially_frozen,
1571                     GDBusWorkerMessageReceivedCallback      message_received_callback,
1572                     GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback,
1573                     GDBusWorkerDisconnectedCallback         disconnected_callback,
1574                     gpointer                                user_data)
1575 {
1576   GDBusWorker *worker;
1577   GSource *idle_source;
1578
1579   g_return_val_if_fail (G_IS_IO_STREAM (stream), NULL);
1580   g_return_val_if_fail (message_received_callback != NULL, NULL);
1581   g_return_val_if_fail (message_about_to_be_sent_callback != NULL, NULL);
1582   g_return_val_if_fail (disconnected_callback != NULL, NULL);
1583
1584   worker = g_new0 (GDBusWorker, 1);
1585   worker->ref_count = 1;
1586
1587   g_mutex_init (&worker->read_lock);
1588   worker->message_received_callback = message_received_callback;
1589   worker->message_about_to_be_sent_callback = message_about_to_be_sent_callback;
1590   worker->disconnected_callback = disconnected_callback;
1591   worker->user_data = user_data;
1592   worker->stream = g_object_ref (stream);
1593   worker->capabilities = capabilities;
1594   worker->cancellable = g_cancellable_new ();
1595   worker->output_pending = FALSE;
1596
1597   worker->frozen = initially_frozen;
1598   worker->received_messages_while_frozen = g_queue_new ();
1599
1600   g_mutex_init (&worker->write_lock);
1601   worker->write_queue = g_queue_new ();
1602
1603   if (G_IS_SOCKET_CONNECTION (worker->stream))
1604     worker->socket = g_socket_connection_get_socket (G_SOCKET_CONNECTION (worker->stream));
1605
1606   worker->shared_thread_data = _g_dbus_shared_thread_ref ();
1607
1608   /* begin reading */
1609   idle_source = g_idle_source_new ();
1610   g_source_set_priority (idle_source, G_PRIORITY_DEFAULT);
1611   g_source_set_callback (idle_source,
1612                          _g_dbus_worker_do_initial_read,
1613                          _g_dbus_worker_ref (worker),
1614                          (GDestroyNotify) _g_dbus_worker_unref);
1615   g_source_attach (idle_source, worker->shared_thread_data->context);
1616   g_source_unref (idle_source);
1617
1618   return worker;
1619 }
1620
1621 /* ---------------------------------------------------------------------------------------------------- */
1622
1623 /* can be called from any thread
1624  *
1625  * write_lock is not held on entry
1626  * output_pending may be true or false
1627  */
1628 void
1629 _g_dbus_worker_close (GDBusWorker         *worker,
1630                       GCancellable        *cancellable,
1631                       GSimpleAsyncResult  *result)
1632 {
1633   CloseData *close_data;
1634
1635   close_data = g_slice_new0 (CloseData);
1636   close_data->worker = _g_dbus_worker_ref (worker);
1637   close_data->cancellable =
1638       (cancellable == NULL ? NULL : g_object_ref (cancellable));
1639   close_data->result = (result == NULL ? NULL : g_object_ref (result));
1640
1641   g_cancellable_cancel (worker->cancellable);
1642   schedule_write_in_worker_thread (worker, NULL, close_data);
1643 }
1644
1645 /* This can be called from any thread - frees worker. Note that
1646  * callbacks might still happen if called from another thread than the
1647  * worker - use your own synchronization primitive in the callbacks.
1648  *
1649  * write_lock is not held on entry
1650  * output_pending may be true or false
1651  */
1652 void
1653 _g_dbus_worker_stop (GDBusWorker *worker)
1654 {
1655   g_atomic_int_set (&worker->stopped, TRUE);
1656
1657   /* Cancel any pending operations and schedule a close of the underlying I/O
1658    * stream in the worker thread
1659    */
1660   _g_dbus_worker_close (worker, NULL, NULL);
1661
1662   /* _g_dbus_worker_close holds a ref until after an idle in the the worker
1663    * thread has run, so we no longer need to unref in an idle like in
1664    * commit 322e25b535
1665    */
1666   _g_dbus_worker_unref (worker);
1667 }
1668
1669 /* ---------------------------------------------------------------------------------------------------- */
1670
1671 /* can be called from any thread (except the worker thread) - blocks
1672  * calling thread until all queued outgoing messages are written and
1673  * the transport has been flushed
1674  *
1675  * write_lock is not held on entry
1676  * output_pending may be true or false
1677  */
1678 gboolean
1679 _g_dbus_worker_flush_sync (GDBusWorker    *worker,
1680                            GCancellable   *cancellable,
1681                            GError        **error)
1682 {
1683   gboolean ret;
1684   FlushData *data;
1685
1686   data = NULL;
1687   ret = TRUE;
1688
1689   /* if the queue is empty, there's nothing to wait for */
1690   g_mutex_lock (&worker->write_lock);
1691   if (g_queue_get_length (worker->write_queue) > 0)
1692     {
1693       data = g_new0 (FlushData, 1);
1694       g_mutex_init (&data->mutex);
1695       g_cond_init (&data->cond);
1696       data->number_to_wait_for = worker->write_num_messages_written + g_queue_get_length (worker->write_queue);
1697       g_mutex_lock (&data->mutex);
1698       worker->write_pending_flushes = g_list_prepend (worker->write_pending_flushes, data);
1699     }
1700   g_mutex_unlock (&worker->write_lock);
1701
1702   if (data != NULL)
1703     {
1704       g_cond_wait (&data->cond, &data->mutex);
1705       g_mutex_unlock (&data->mutex);
1706
1707       /* note:the element is removed from worker->write_pending_flushes in flush_cb() above */
1708       g_cond_clear (&data->cond);
1709       g_mutex_clear (&data->mutex);
1710       if (data->error != NULL)
1711         {
1712           ret = FALSE;
1713           g_propagate_error (error, data->error);
1714         }
1715       g_free (data);
1716     }
1717
1718   return ret;
1719 }
1720
1721 /* ---------------------------------------------------------------------------------------------------- */
1722
1723 #define G_DBUS_DEBUG_AUTHENTICATION (1<<0)
1724 #define G_DBUS_DEBUG_TRANSPORT      (1<<1)
1725 #define G_DBUS_DEBUG_MESSAGE        (1<<2)
1726 #define G_DBUS_DEBUG_PAYLOAD        (1<<3)
1727 #define G_DBUS_DEBUG_CALL           (1<<4)
1728 #define G_DBUS_DEBUG_SIGNAL         (1<<5)
1729 #define G_DBUS_DEBUG_INCOMING       (1<<6)
1730 #define G_DBUS_DEBUG_RETURN         (1<<7)
1731 #define G_DBUS_DEBUG_EMISSION       (1<<8)
1732 #define G_DBUS_DEBUG_ADDRESS        (1<<9)
1733
1734 static gint _gdbus_debug_flags = 0;
1735
1736 gboolean
1737 _g_dbus_debug_authentication (void)
1738 {
1739   _g_dbus_initialize ();
1740   return (_gdbus_debug_flags & G_DBUS_DEBUG_AUTHENTICATION) != 0;
1741 }
1742
1743 gboolean
1744 _g_dbus_debug_transport (void)
1745 {
1746   _g_dbus_initialize ();
1747   return (_gdbus_debug_flags & G_DBUS_DEBUG_TRANSPORT) != 0;
1748 }
1749
1750 gboolean
1751 _g_dbus_debug_message (void)
1752 {
1753   _g_dbus_initialize ();
1754   return (_gdbus_debug_flags & G_DBUS_DEBUG_MESSAGE) != 0;
1755 }
1756
1757 gboolean
1758 _g_dbus_debug_payload (void)
1759 {
1760   _g_dbus_initialize ();
1761   return (_gdbus_debug_flags & G_DBUS_DEBUG_PAYLOAD) != 0;
1762 }
1763
1764 gboolean
1765 _g_dbus_debug_call (void)
1766 {
1767   _g_dbus_initialize ();
1768   return (_gdbus_debug_flags & G_DBUS_DEBUG_CALL) != 0;
1769 }
1770
1771 gboolean
1772 _g_dbus_debug_signal (void)
1773 {
1774   _g_dbus_initialize ();
1775   return (_gdbus_debug_flags & G_DBUS_DEBUG_SIGNAL) != 0;
1776 }
1777
1778 gboolean
1779 _g_dbus_debug_incoming (void)
1780 {
1781   _g_dbus_initialize ();
1782   return (_gdbus_debug_flags & G_DBUS_DEBUG_INCOMING) != 0;
1783 }
1784
1785 gboolean
1786 _g_dbus_debug_return (void)
1787 {
1788   _g_dbus_initialize ();
1789   return (_gdbus_debug_flags & G_DBUS_DEBUG_RETURN) != 0;
1790 }
1791
1792 gboolean
1793 _g_dbus_debug_emission (void)
1794 {
1795   _g_dbus_initialize ();
1796   return (_gdbus_debug_flags & G_DBUS_DEBUG_EMISSION) != 0;
1797 }
1798
1799 gboolean
1800 _g_dbus_debug_address (void)
1801 {
1802   _g_dbus_initialize ();
1803   return (_gdbus_debug_flags & G_DBUS_DEBUG_ADDRESS) != 0;
1804 }
1805
1806 G_LOCK_DEFINE_STATIC (print_lock);
1807
1808 void
1809 _g_dbus_debug_print_lock (void)
1810 {
1811   G_LOCK (print_lock);
1812 }
1813
1814 void
1815 _g_dbus_debug_print_unlock (void)
1816 {
1817   G_UNLOCK (print_lock);
1818 }
1819
1820 /*
1821  * _g_dbus_initialize:
1822  *
1823  * Does various one-time init things such as
1824  *
1825  *  - registering the G_DBUS_ERROR error domain
1826  *  - parses the G_DBUS_DEBUG environment variable
1827  */
1828 void
1829 _g_dbus_initialize (void)
1830 {
1831   static volatile gsize initialized = 0;
1832
1833   if (g_once_init_enter (&initialized))
1834     {
1835       volatile GQuark g_dbus_error_domain;
1836       const gchar *debug;
1837
1838       g_dbus_error_domain = G_DBUS_ERROR;
1839       (g_dbus_error_domain); /* To avoid -Wunused-but-set-variable */
1840
1841       debug = g_getenv ("G_DBUS_DEBUG");
1842       if (debug != NULL)
1843         {
1844           const GDebugKey keys[] = {
1845             { "authentication", G_DBUS_DEBUG_AUTHENTICATION },
1846             { "transport",      G_DBUS_DEBUG_TRANSPORT      },
1847             { "message",        G_DBUS_DEBUG_MESSAGE        },
1848             { "payload",        G_DBUS_DEBUG_PAYLOAD        },
1849             { "call",           G_DBUS_DEBUG_CALL           },
1850             { "signal",         G_DBUS_DEBUG_SIGNAL         },
1851             { "incoming",       G_DBUS_DEBUG_INCOMING       },
1852             { "return",         G_DBUS_DEBUG_RETURN         },
1853             { "emission",       G_DBUS_DEBUG_EMISSION       },
1854             { "address",        G_DBUS_DEBUG_ADDRESS        }
1855           };
1856
1857           _gdbus_debug_flags = g_parse_debug_string (debug, keys, G_N_ELEMENTS (keys));
1858           if (_gdbus_debug_flags & G_DBUS_DEBUG_PAYLOAD)
1859             _gdbus_debug_flags |= G_DBUS_DEBUG_MESSAGE;
1860         }
1861
1862       g_once_init_leave (&initialized, 1);
1863     }
1864 }
1865
1866 /* ---------------------------------------------------------------------------------------------------- */
1867
1868 GVariantType *
1869 _g_dbus_compute_complete_signature (GDBusArgInfo **args)
1870 {
1871   const GVariantType *arg_types[256];
1872   guint n;
1873
1874   if (args)
1875     for (n = 0; args[n] != NULL; n++)
1876       {
1877         /* DBus places a hard limit of 255 on signature length.
1878          * therefore number of args must be less than 256.
1879          */
1880         g_assert (n < 256);
1881
1882         arg_types[n] = G_VARIANT_TYPE (args[n]->signature);
1883
1884         if G_UNLIKELY (arg_types[n] == NULL)
1885           return NULL;
1886       }
1887   else
1888     n = 0;
1889
1890   return g_variant_type_new_tuple (arg_types, n);
1891 }
1892
1893 /* ---------------------------------------------------------------------------------------------------- */
1894
1895 #ifdef G_OS_WIN32
1896
1897 extern BOOL WINAPI ConvertSidToStringSidA (PSID Sid, LPSTR *StringSid);
1898
1899 gchar *
1900 _g_dbus_win32_get_user_sid (void)
1901 {
1902   HANDLE h;
1903   TOKEN_USER *user;
1904   DWORD token_information_len;
1905   PSID psid;
1906   gchar *sid;
1907   gchar *ret;
1908
1909   ret = NULL;
1910   user = NULL;
1911   h = INVALID_HANDLE_VALUE;
1912
1913   if (!OpenProcessToken (GetCurrentProcess (), TOKEN_QUERY, &h))
1914     {
1915       g_warning ("OpenProcessToken failed with error code %d", (gint) GetLastError ());
1916       goto out;
1917     }
1918
1919   /* Get length of buffer */
1920   token_information_len = 0;
1921   if (!GetTokenInformation (h, TokenUser, NULL, 0, &token_information_len))
1922     {
1923       if (GetLastError () != ERROR_INSUFFICIENT_BUFFER)
1924         {
1925           g_warning ("GetTokenInformation() failed with error code %d", (gint) GetLastError ());
1926           goto out;
1927         }
1928     }
1929   user = g_malloc (token_information_len);
1930   if (!GetTokenInformation (h, TokenUser, user, token_information_len, &token_information_len))
1931     {
1932       g_warning ("GetTokenInformation() failed with error code %d", (gint) GetLastError ());
1933       goto out;
1934     }
1935
1936   psid = user->User.Sid;
1937   if (!IsValidSid (psid))
1938     {
1939       g_warning ("Invalid SID");
1940       goto out;
1941     }
1942
1943   if (!ConvertSidToStringSidA (psid, &sid))
1944     {
1945       g_warning ("Invalid SID");
1946       goto out;
1947     }
1948
1949   ret = g_strdup (sid);
1950   LocalFree (sid);
1951
1952 out:
1953   g_free (user);
1954   if (h != INVALID_HANDLE_VALUE)
1955     CloseHandle (h);
1956   return ret;
1957 }
1958 #endif
1959
1960 /* ---------------------------------------------------------------------------------------------------- */
1961
1962 gchar *
1963 _g_dbus_get_machine_id (GError **error)
1964 {
1965   gchar *ret;
1966   /* TODO: use PACKAGE_LOCALSTATEDIR ? */
1967   ret = NULL;
1968   if (!g_file_get_contents ("/var/lib/dbus/machine-id",
1969                             &ret,
1970                             NULL,
1971                             error))
1972     {
1973       g_prefix_error (error, _("Unable to load /var/lib/dbus/machine-id: "));
1974     }
1975   else
1976     {
1977       /* TODO: validate value */
1978       g_strstrip (ret);
1979     }
1980   return ret;
1981 }
1982
1983 /* ---------------------------------------------------------------------------------------------------- */
1984
1985 gchar *
1986 _g_dbus_enum_to_string (GType enum_type, gint value)
1987 {
1988   gchar *ret;
1989   GEnumClass *klass;
1990   GEnumValue *enum_value;
1991
1992   klass = g_type_class_ref (enum_type);
1993   enum_value = g_enum_get_value (klass, value);
1994   if (enum_value != NULL)
1995     ret = g_strdup (enum_value->value_nick);
1996   else
1997     ret = g_strdup_printf ("unknown (value %d)", value);
1998   g_type_class_unref (klass);
1999   return ret;
2000 }
2001
2002 /* ---------------------------------------------------------------------------------------------------- */
2003
2004 static void
2005 write_message_print_transport_debug (gssize bytes_written,
2006                                      MessageToWriteData *data)
2007 {
2008   if (G_LIKELY (!_g_dbus_debug_transport ()))
2009     goto out;
2010
2011   _g_dbus_debug_print_lock ();
2012   g_print ("========================================================================\n"
2013            "GDBus-debug:Transport:\n"
2014            "  >>>> WROTE %" G_GSIZE_FORMAT " bytes of message with serial %d and\n"
2015            "       size %" G_GSIZE_FORMAT " from offset %" G_GSIZE_FORMAT " on a %s\n",
2016            bytes_written,
2017            g_dbus_message_get_serial (data->message),
2018            data->blob_size,
2019            data->total_written,
2020            g_type_name (G_TYPE_FROM_INSTANCE (g_io_stream_get_output_stream (data->worker->stream))));
2021   _g_dbus_debug_print_unlock ();
2022  out:
2023   ;
2024 }
2025
2026 /* ---------------------------------------------------------------------------------------------------- */
2027
2028 static void
2029 read_message_print_transport_debug (gssize bytes_read,
2030                                     GDBusWorker *worker)
2031 {
2032   gsize size;
2033   gint32 serial;
2034   gint32 message_length;
2035
2036   if (G_LIKELY (!_g_dbus_debug_transport ()))
2037     goto out;
2038
2039   size = bytes_read + worker->read_buffer_cur_size;
2040   serial = 0;
2041   message_length = 0;
2042   if (size >= 16)
2043     message_length = g_dbus_message_bytes_needed ((guchar *) worker->read_buffer, size, NULL);
2044   if (size >= 1)
2045     {
2046       switch (worker->read_buffer[0])
2047         {
2048         case 'l':
2049           if (size >= 12)
2050             serial = GUINT32_FROM_LE (((guint32 *) worker->read_buffer)[2]);
2051           break;
2052         case 'B':
2053           if (size >= 12)
2054             serial = GUINT32_FROM_BE (((guint32 *) worker->read_buffer)[2]);
2055           break;
2056         default:
2057           /* an error will be set elsewhere if this happens */
2058           goto out;
2059         }
2060     }
2061
2062     _g_dbus_debug_print_lock ();
2063   g_print ("========================================================================\n"
2064            "GDBus-debug:Transport:\n"
2065            "  <<<< READ %" G_GSIZE_FORMAT " bytes of message with serial %d and\n"
2066            "       size %d to offset %" G_GSIZE_FORMAT " from a %s\n",
2067            bytes_read,
2068            serial,
2069            message_length,
2070            worker->read_buffer_cur_size,
2071            g_type_name (G_TYPE_FROM_INSTANCE (g_io_stream_get_input_stream (worker->stream))));
2072   _g_dbus_debug_print_unlock ();
2073  out:
2074   ;
2075 }
2076
2077 /* ---------------------------------------------------------------------------------------------------- */
2078
2079 gboolean
2080 _g_signal_accumulator_false_handled (GSignalInvocationHint *ihint,
2081                                      GValue                *return_accu,
2082                                      const GValue          *handler_return,
2083                                      gpointer               dummy)
2084 {
2085   gboolean continue_emission;
2086   gboolean signal_return;
2087
2088   signal_return = g_value_get_boolean (handler_return);
2089   g_value_set_boolean (return_accu, signal_return);
2090   continue_emission = signal_return;
2091
2092   return continue_emission;
2093 }