glib/gio/gdbusprivate.h
David Zeuthen 8a3a4596e2 Bug 626748 – Use async methods for writing and handle EAGAIN
If sending a lot of data and/or the other peer is not reading it, then
socket buffers can overflow. This is communicated from the kernel by
returning EAGAIN. In GIO, it is modelled by g_output_stream_write()
and g_socket_send_message() returning G_IO_ERROR_WOULD_BLOCK.

It is also problematic that that we're using synchronous IO in the
shared GDBus IO thread. It means that one GDBusConnection can lock up
others.

It turns out that by porting from g_output_stream_write() to
g_output_stream_write_async() we fix the EAGAIN issue. For GSocket, we
still need to handle things manually (by creating a GSource) as
g_socket_send_message() is used.

We check the new behavior in Michael's producer/consumer test case (at
/gdbus/overflow in gdbus-peer.c) added in the last commit.

Also add a test case that sends and receives a 20 MiB message.

Also add a new `transport' G_DBUS_DEBUG option so it is easy to
inspect partial writes:

 $ G_DBUS_DEBUG=transport ./gdbus-connection -p /gdbus/connection/large_message
 [...]
 ========================================================================
 GDBus-debug:Transport:
   >>>> WROTE 128000 bytes of message with serial 4 and
        size 20971669 from offset 0 on a GSocketOutputStream
 ========================================================================
 GDBus-debug:Transport:
   >>>> WROTE 128000 bytes of message with serial 4 and
        size 20971669 from offset 128000 on a GSocketOutputStream
 ========================================================================
 GDBus-debug:Transport:
   >>>> WROTE 128000 bytes of message with serial 4 and
        size 20971669 from offset 256000 on a GSocketOutputStream
 [...]
 ========================================================================
 GDBus-debug:Transport:
   >>>> WROTE 43669 bytes of message with serial 4 and
        size 20971669 from offset 20928000 on a GSocketOutputStream
 [...]
 ========================================================================
 GDBus-debug:Transport:
   <<<< READ 16 bytes of message with serial 3 and
        size 20971620 to offset 0 from a GSocketInputStream
 ========================================================================
 GDBus-debug:Transport:
   <<<< READ 15984 bytes of message with serial 3 and
        size 20971620 to offset 16 from a GSocketInputStream
 ========================================================================
 GDBus-debug:Transport:
   <<<< READ 16000 bytes of message with serial 3 and
        size 20971620 to offset 16000 from a GSocketInputStream
 [...]
 ========================================================================
 GDBus-debug:Transport:
   <<<< READ 144000 bytes of message with serial 3 and
        size 20971620 to offset 20720000 from a GSocketInputStream
 ========================================================================
 GDBus-debug:Transport:
   <<<< READ 107620 bytes of message with serial 3 and
        size 20971620 to offset 20864000 from a GSocketInputStream
 OK

https://bugzilla.gnome.org/show_bug.cgi?id=626748

Signed-off-by: David Zeuthen <davidz@redhat.com>
2010-08-16 13:54:13 -04:00

118 lines
4.9 KiB
C

/* GDBus - GLib D-Bus Library
*
* Copyright (C) 2008-2010 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: David Zeuthen <davidz@redhat.com>
*/
#if !defined (GIO_COMPILATION)
#error "gdbusprivate.h is a private header file."
#endif
#ifndef __G_DBUS_PRIVATE_H__
#define __G_DBUS_PRIVATE_H__
#include <gio/giotypes.h>
G_BEGIN_DECLS
/* ---------------------------------------------------------------------------------------------------- */
typedef struct GDBusWorker GDBusWorker;
typedef void (*GDBusWorkerMessageReceivedCallback) (GDBusWorker *worker,
GDBusMessage *message,
gpointer user_data);
typedef gboolean (*GDBusWorkerMessageAboutToBeSentCallback) (GDBusWorker *worker,
GDBusMessage *message,
gpointer user_data);
typedef void (*GDBusWorkerDisconnectedCallback) (GDBusWorker *worker,
gboolean remote_peer_vanished,
GError *error,
gpointer user_data);
/* This function may be called from any thread - callbacks will be in the shared private message thread
* and must not block.
*/
GDBusWorker *_g_dbus_worker_new (GIOStream *stream,
GDBusCapabilityFlags capabilities,
gboolean initially_frozen,
GDBusWorkerMessageReceivedCallback message_received_callback,
GDBusWorkerMessageAboutToBeSentCallback message_about_to_be_sent_callback,
GDBusWorkerDisconnectedCallback disconnected_callback,
gpointer user_data);
/* can be called from any thread - steals blob */
void _g_dbus_worker_send_message (GDBusWorker *worker,
GDBusMessage *message,
gchar *blob,
gsize blob_len);
/* can be called from any thread */
void _g_dbus_worker_stop (GDBusWorker *worker);
/* can be called from any thread */
void _g_dbus_worker_unfreeze (GDBusWorker *worker);
/* can be called from any thread (except the worker thread) */
gboolean _g_dbus_worker_flush_sync (GDBusWorker *worker,
GCancellable *cancellable,
GError **error);
/* ---------------------------------------------------------------------------------------------------- */
void _g_dbus_initialize (void);
gboolean _g_dbus_debug_authentication (void);
gboolean _g_dbus_debug_transport (void);
gboolean _g_dbus_debug_message (void);
gboolean _g_dbus_debug_payload (void);
gboolean _g_dbus_debug_call (void);
gboolean _g_dbus_debug_signal (void);
gboolean _g_dbus_debug_incoming (void);
gboolean _g_dbus_debug_return (void);
gboolean _g_dbus_debug_emission (void);
gboolean _g_dbus_debug_address (void);
void _g_dbus_debug_print_lock (void);
void _g_dbus_debug_print_unlock (void);
gboolean _g_dbus_address_parse_entry (const gchar *address_entry,
gchar **out_transport_name,
GHashTable **out_key_value_pairs,
GError **error);
GVariantType * _g_dbus_compute_complete_signature (GDBusArgInfo **args);
gchar *_g_dbus_hexdump (const gchar *data, gsize len, guint indent);
/* ---------------------------------------------------------------------------------------------------- */
#ifdef G_OS_WIN32
gchar *_g_dbus_win32_get_user_sid (void);
#endif
gchar *_g_dbus_get_machine_id (GError **error);
gchar *_g_dbus_enum_to_string (GType enum_type, gint value);
G_END_DECLS
#endif /* __G_DBUS_PRIVATE_H__ */