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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-connection.c DBusConnection object
*
* Copyright (C) 2002-2006 Red Hat Inc.
*
* Licensed under the Academic Free License version 2.1
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <config.h>
#include <signal.h>
#include "dbus-shared.h"
#include "dbus-connection.h"
#include "dbus-list.h"
#include "dbus-timeout.h"
#include "dbus-transport.h"
#include "dbus-watch.h"
#include "dbus-connection-internal.h"
#include "dbus-pending-call-internal.h"
#include "dbus-list.h"
#include "dbus-hash.h"
#include "dbus-message-internal.h"
#include "dbus-message-private.h"
#include "dbus-threads.h"
#include "dbus-protocol.h"
#include "dbus-dataslot.h"
#include "dbus-string.h"
#include "dbus-signature.h"
#include "dbus-pending-call.h"
#include "dbus-object-tree.h"
#include "dbus-threads-internal.h"
#include "dbus-bus.h"
#include "dbus-marshal-basic.h"
#ifdef DBUS_DISABLE_CHECKS
#define TOOK_LOCK_CHECK(connection)
#define RELEASING_LOCK_CHECK(connection)
#define HAVE_LOCK_CHECK(connection)
#else
#define TOOK_LOCK_CHECK(connection) do { \
_dbus_assert (!(connection)->have_connection_lock); \
(connection)->have_connection_lock = TRUE; \
} while (0)
#define RELEASING_LOCK_CHECK(connection) do { \
_dbus_assert ((connection)->have_connection_lock); \
(connection)->have_connection_lock = FALSE; \
} while (0)
#define HAVE_LOCK_CHECK(connection) _dbus_assert ((connection)->have_connection_lock)
/* A "DO_NOT_HAVE_LOCK_CHECK" is impossible since we need the lock to check the flag */
#endif
#define TRACE_LOCKS 0
#define CONNECTION_LOCK(connection) do { \
if (TRACE_LOCKS) { _dbus_verbose ("LOCK\n"); } \
_dbus_rmutex_lock ((connection)->mutex); \
TOOK_LOCK_CHECK (connection); \
} while (0)
#define CONNECTION_UNLOCK(connection) _dbus_connection_unlock (connection)
#define SLOTS_LOCK(connection) do { \
_dbus_rmutex_lock ((connection)->slot_mutex); \
} while (0)
#define SLOTS_UNLOCK(connection) do { \
_dbus_rmutex_unlock ((connection)->slot_mutex); \
} while (0)
#define DISPATCH_STATUS_NAME(s) \
((s) == DBUS_DISPATCH_COMPLETE ? "complete" : \
(s) == DBUS_DISPATCH_DATA_REMAINS ? "data remains" : \
(s) == DBUS_DISPATCH_NEED_MEMORY ? "need memory" : \
"???")
/**
* @defgroup DBusConnection DBusConnection
* @ingroup DBus
* @brief Connection to another application
*
* A DBusConnection represents a connection to another
* application. Messages can be sent and received via this connection.
* The other application may be a message bus; for convenience, the
* function dbus_bus_get() is provided to automatically open a
* connection to the well-known message buses.
*
* In brief a DBusConnection is a message queue associated with some
* message transport mechanism such as a socket. The connection
* maintains a queue of incoming messages and a queue of outgoing
* messages.
*
* Several functions use the following terms:
* <ul>
* <li><b>read</b> means to fill the incoming message queue by reading from the socket</li>
* <li><b>write</b> means to drain the outgoing queue by writing to the socket</li>
* <li><b>dispatch</b> means to drain the incoming queue by invoking application-provided message handlers</li>
* </ul>
*
* The function dbus_connection_read_write_dispatch() for example does all
* three of these things, offering a simple alternative to a main loop.
*
* In an application with a main loop, the read/write/dispatch
* operations are usually separate.
*
* The connection provides #DBusWatch and #DBusTimeout objects to
* the main loop. These are used to know when reading, writing, or
* dispatching should be performed.
*
* Incoming messages are processed
* by calling dbus_connection_dispatch(). dbus_connection_dispatch()
* runs any handlers registered for the topmost message in the message
* queue, then discards the message, then returns.
*
* dbus_connection_get_dispatch_status() indicates whether
* messages are currently in the queue that need dispatching.
* dbus_connection_set_dispatch_status_function() allows
* you to set a function to be used to monitor the dispatch status.
*
* If you're using GLib or Qt add-on libraries for D-Bus, there are
* special convenience APIs in those libraries that hide
* all the details of dispatch and watch/timeout monitoring.
* For example, dbus_connection_setup_with_g_main().
*
* If you aren't using these add-on libraries, but want to process
* messages asynchronously, you must manually call
* dbus_connection_set_dispatch_status_function(),
* dbus_connection_set_watch_functions(),
* dbus_connection_set_timeout_functions() providing appropriate
* functions to integrate the connection with your application's main
* loop. This can be tricky to get right; main loops are not simple.
*
* If you don't need to be asynchronous, you can ignore #DBusWatch,
* #DBusTimeout, and dbus_connection_dispatch(). Instead,
* dbus_connection_read_write_dispatch() can be used.
*
* Or, in <em>very</em> simple applications,
* dbus_connection_pop_message() may be all you need, allowing you to
* avoid setting up any handler functions (see
* dbus_connection_add_filter(),
* dbus_connection_register_object_path() for more on handlers).
*
* When you use dbus_connection_send() or one of its variants to send
* a message, the message is added to the outgoing queue. It's
* actually written to the network later; either in
* dbus_watch_handle() invoked by your main loop, or in
* dbus_connection_flush() which blocks until it can write out the
* entire outgoing queue. The GLib/Qt add-on libraries again
* handle the details here for you by setting up watch functions.
*
* When a connection is disconnected, you are guaranteed to get a
* signal "Disconnected" from the interface
* #DBUS_INTERFACE_LOCAL, path
* #DBUS_PATH_LOCAL.
*
* You may not drop the last reference to a #DBusConnection
* until that connection has been disconnected.
*
* You may dispatch the unprocessed incoming message queue even if the
* connection is disconnected. However, "Disconnected" will always be
* the last message in the queue (obviously no messages are received
* after disconnection).
*
* After calling dbus_threads_init(), #DBusConnection has thread
* locks and drops them when invoking user callbacks, so in general is
* transparently threadsafe. However, #DBusMessage does NOT have
* thread locks; you must not send the same message to multiple
* #DBusConnection if those connections will be used from different threads,
* for example.
*
* Also, if you dispatch or pop messages from multiple threads, it
* may work in the sense that it won't crash, but it's tough to imagine
* sane results; it will be completely unpredictable which messages
* go to which threads.
*
* It's recommended to dispatch from a single thread.
*
* The most useful function to call from multiple threads at once
* is dbus_connection_send_with_reply_and_block(). That is,
* multiple threads can make method calls at the same time.
*
* If you aren't using threads, you can use a main loop and
* dbus_pending_call_set_notify() to achieve a similar result.
*/
/**
* @defgroup DBusConnectionInternals DBusConnection implementation details
* @ingroup DBusInternals
* @brief Implementation details of DBusConnection
*
* @{
*/
#ifdef DBUS_ENABLE_VERBOSE_MODE
static void
_dbus_connection_trace_ref (DBusConnection *connection,
int old_refcount,
int new_refcount,
const char *why)
{
static int enabled = -1;
_dbus_trace_ref ("DBusConnection", connection, old_refcount, new_refcount,
why, "DBUS_CONNECTION_TRACE", &enabled);
}
#else
#define _dbus_connection_trace_ref(c,o,n,w) \
do \
{\
(void) (o); \
(void) (n); \
} while (0)
#endif
/**
* Internal struct representing a message filter function
*/
typedef struct DBusMessageFilter DBusMessageFilter;
/**
* Internal struct representing a message filter function
*/
struct DBusMessageFilter
{
DBusAtomic refcount; /**< Reference count */
DBusHandleMessageFunction function; /**< Function to call to filter */
void *user_data; /**< User data for the function */
DBusFreeFunction free_user_data_function; /**< Function to free the user data */
};
/**
* Internals of DBusPreallocatedSend
*/
struct DBusPreallocatedSend
{
DBusConnection *connection; /**< Connection we'd send the message to */
DBusList *queue_link; /**< Preallocated link in the queue */
DBusList *counter_link; /**< Preallocated link in the resource counter */
};
#if HAVE_DECL_MSG_NOSIGNAL
static dbus_bool_t _dbus_modify_sigpipe = FALSE;
#else
static dbus_bool_t _dbus_modify_sigpipe = TRUE;
#endif
/**
* Implementation details of DBusConnection. All fields are private.
*/
struct DBusConnection
{
DBusAtomic refcount; /**< Reference count. */
DBusRMutex *mutex; /**< Lock on the entire DBusConnection */
DBusCMutex *dispatch_mutex; /**< Protects dispatch_acquired */
DBusCondVar *dispatch_cond; /**< Notify when dispatch_acquired is available */
DBusCMutex *io_path_mutex; /**< Protects io_path_acquired */
DBusCondVar *io_path_cond; /**< Notify when io_path_acquired is available */
DBusList *outgoing_messages; /**< Queue of messages we need to send, send the end of the list first. */
DBusList *incoming_messages; /**< Queue of messages we have received, end of the list received most recently. */
DBusList *expired_messages; /**< Messages that will be released when we next unlock. */
DBusMessage *message_borrowed; /**< Filled in if the first incoming message has been borrowed;
* dispatch_acquired will be set by the borrower
*/
int n_outgoing; /**< Length of outgoing queue. */
int n_incoming; /**< Length of incoming queue. */
DBusCounter *outgoing_counter; /**< Counts size of outgoing messages. */
DBusTransport *transport; /**< Object that sends/receives messages over network. */
DBusWatchList *watches; /**< Stores active watches. */
DBusTimeoutList *timeouts; /**< Stores active timeouts. */
DBusList *filter_list; /**< List of filters. */
DBusRMutex *slot_mutex; /**< Lock on slot_list so overall connection lock need not be taken */
DBusDataSlotList slot_list; /**< Data stored by allocated integer ID */
DBusHashTable *pending_replies; /**< Hash of message serials to #DBusPendingCall. */
dbus_uint32_t client_serial; /**< Client serial. Increments each time a message is sent */
DBusList *disconnect_message_link; /**< Preallocated list node for queueing the disconnection message */
DBusWakeupMainFunction wakeup_main_function; /**< Function to wake up the mainloop */
void *wakeup_main_data; /**< Application data for wakeup_main_function */
DBusFreeFunction free_wakeup_main_data; /**< free wakeup_main_data */
DBusDispatchStatusFunction dispatch_status_function; /**< Function on dispatch status changes */
void *dispatch_status_data; /**< Application data for dispatch_status_function */
DBusFreeFunction free_dispatch_status_data; /**< free dispatch_status_data */
DBusDispatchStatus last_dispatch_status; /**< The last dispatch status we reported to the application. */
DBusObjectTree *objects; /**< Object path handlers registered with this connection */
char *server_guid; /**< GUID of server if we are in shared_connections, #NULL if server GUID is unknown or connection is private */
/* These two MUST be bools and not bitfields, because they are protected by a separate lock
* from connection->mutex and all bitfields in a word have to be read/written together.
* So you can't have a different lock for different bitfields in the same word.
*/
dbus_bool_t dispatch_acquired; /**< Someone has dispatch path (can drain incoming queue) */
dbus_bool_t io_path_acquired; /**< Someone has transport io path (can use the transport to read/write messages) */
unsigned int shareable : 1; /**< #TRUE if libdbus owns a reference to the connection and can return it from dbus_connection_open() more than once */
unsigned int exit_on_disconnect : 1; /**< If #TRUE, exit after handling disconnect signal */
unsigned int route_peer_messages : 1; /**< If #TRUE, if org.freedesktop.DBus.Peer messages have a bus name, don't handle them automatically */
unsigned int disconnected_message_arrived : 1; /**< We popped or are dispatching the disconnected message.
* if the disconnect_message_link is NULL then we queued it, but
* this flag is whether it got to the head of the queue.
*/
unsigned int disconnected_message_processed : 1; /**< We did our default handling of the disconnected message,
* such as closing the connection.
*/
#ifndef DBUS_DISABLE_CHECKS
unsigned int have_connection_lock : 1; /**< Used to check locking */
#endif
#ifndef DBUS_DISABLE_CHECKS
int generation; /**< _dbus_current_generation that should correspond to this connection */
#endif
};
static DBusDispatchStatus _dbus_connection_get_dispatch_status_unlocked (DBusConnection *connection);
static void _dbus_connection_update_dispatch_status_and_unlock (DBusConnection *connection,
DBusDispatchStatus new_status);
static void _dbus_connection_last_unref (DBusConnection *connection);
static void _dbus_connection_acquire_dispatch (DBusConnection *connection);
static void _dbus_connection_release_dispatch (DBusConnection *connection);
static DBusDispatchStatus _dbus_connection_flush_unlocked (DBusConnection *connection);
static void _dbus_connection_close_possibly_shared_and_unlock (DBusConnection *connection);
static dbus_bool_t _dbus_connection_get_is_connected_unlocked (DBusConnection *connection);
static dbus_bool_t _dbus_connection_peek_for_reply_unlocked (DBusConnection *connection,
dbus_uint32_t client_serial);
static DBusMessageFilter *
_dbus_message_filter_ref (DBusMessageFilter *filter)
{
#ifdef DBUS_DISABLE_ASSERT
_dbus_atomic_inc (&filter->refcount);
#else
dbus_int32_t old_value;
old_value = _dbus_atomic_inc (&filter->refcount);
_dbus_assert (old_value > 0);
#endif
return filter;
}
static void
_dbus_message_filter_unref (DBusMessageFilter *filter)
{
dbus_int32_t old_value;
old_value = _dbus_atomic_dec (&filter->refcount);
_dbus_assert (old_value > 0);
if (old_value == 1)
{
if (filter->free_user_data_function)
(* filter->free_user_data_function) (filter->user_data);
dbus_free (filter);
}
}
/**
* Acquires the connection lock.
*
* @param connection the connection.
*/
void
_dbus_connection_lock (DBusConnection *connection)
{
CONNECTION_LOCK (connection);
}
/**
* Releases the connection lock.
*
* @param connection the connection.
*/
void
_dbus_connection_unlock (DBusConnection *connection)
{
DBusList *expired_messages;
DBusList *iter;
if (TRACE_LOCKS)
{
_dbus_verbose ("UNLOCK\n");
}
/* If we had messages that expired (fell off the incoming or outgoing
* queues) while we were locked, actually release them now */
expired_messages = connection->expired_messages;
connection->expired_messages = NULL;
RELEASING_LOCK_CHECK (connection);
_dbus_rmutex_unlock (connection->mutex);
for (iter = _dbus_list_pop_first_link (&expired_messages);
iter != NULL;
iter = _dbus_list_pop_first_link (&expired_messages))
{
DBusMessage *message = iter->data;
dbus_message_unref (message);
_dbus_list_free_link (iter);
}
}
/**
* Wakes up the main loop if it is sleeping
* Needed if we're e.g. queueing outgoing messages
* on a thread while the mainloop sleeps.
*
* @param connection the connection.
*/
static void
_dbus_connection_wakeup_mainloop (DBusConnection *connection)
{
if (connection->wakeup_main_function)
(*connection->wakeup_main_function) (connection->wakeup_main_data);
}
#ifdef DBUS_BUILD_TESTS
/**
* Gets the locks so we can examine them
*
* @param connection the connection.
* @param mutex_loc return for the location of the main mutex pointer
* @param dispatch_mutex_loc return location of the dispatch mutex pointer
* @param io_path_mutex_loc return location of the io_path mutex pointer
* @param dispatch_cond_loc return location of the dispatch conditional
* variable pointer
* @param io_path_cond_loc return location of the io_path conditional
* variable pointer
*/
void
_dbus_connection_test_get_locks (DBusConnection *connection,
DBusMutex **mutex_loc,
DBusMutex **dispatch_mutex_loc,
DBusMutex **io_path_mutex_loc,
DBusCondVar **dispatch_cond_loc,
DBusCondVar **io_path_cond_loc)
{
*mutex_loc = (DBusMutex *) connection->mutex;
*dispatch_mutex_loc = (DBusMutex *) connection->dispatch_mutex;
*io_path_mutex_loc = (DBusMutex *) connection->io_path_mutex;
*dispatch_cond_loc = connection->dispatch_cond;
*io_path_cond_loc = connection->io_path_cond;
}
#endif
/**
* Adds a message-containing list link to the incoming message queue,
* taking ownership of the link and the message's current refcount.
* Cannot fail due to lack of memory.
*
* @param connection the connection.
* @param link the message link to queue.
*/
void
_dbus_connection_queue_received_message_link (DBusConnection *connection,
DBusList *link)
{
DBusPendingCall *pending;
dbus_uint32_t reply_serial;
DBusMessage *message;
_dbus_assert (_dbus_transport_get_is_authenticated (connection->transport));
_dbus_list_append_link (&connection->incoming_messages,
link);
message = link->data;
/* If this is a reply we're waiting on, remove timeout for it */
reply_serial = dbus_message_get_reply_serial (message);
if (reply_serial != 0)
{
pending = _dbus_hash_table_lookup_int (connection->pending_replies,
reply_serial);
if (pending != NULL)
{
if (_dbus_pending_call_is_timeout_added_unlocked (pending))
_dbus_connection_remove_timeout_unlocked (connection,
_dbus_pending_call_get_timeout_unlocked (pending));
_dbus_pending_call_set_timeout_added_unlocked (pending, FALSE);
}
}
connection->n_incoming += 1;
_dbus_connection_wakeup_mainloop (connection);
_dbus_verbose ("Message %p (%s %s %s %s '%s' reply to %u) added to incoming queue %p, %d incoming\n",
message,
dbus_message_type_to_string (dbus_message_get_type (message)),
dbus_message_get_path (message) ?
dbus_message_get_path (message) :
"no path",
dbus_message_get_interface (message) ?
dbus_message_get_interface (message) :
"no interface",
dbus_message_get_member (message) ?
dbus_message_get_member (message) :
"no member",
dbus_message_get_signature (message),
dbus_message_get_reply_serial (message),
connection,
connection->n_incoming);
_dbus_message_trace_ref (message, -1, -1,
"_dbus_conection_queue_received_message_link");
}
/**
* Adds a link + message to the incoming message queue.
* Can't fail. Takes ownership of both link and message.
*
* @param connection the connection.
* @param link the list node and message to queue.
*
*/
void
_dbus_connection_queue_synthesized_message_link (DBusConnection *connection,
DBusList *link)
{
HAVE_LOCK_CHECK (connection);
_dbus_list_append_link (&connection->incoming_messages, link);
connection->n_incoming += 1;
_dbus_connection_wakeup_mainloop (connection);
_dbus_message_trace_ref (link->data, -1, -1,
"_dbus_connection_queue_synthesized_message_link");
_dbus_verbose ("Synthesized message %p added to incoming queue %p, %d incoming\n",
link->data, connection, connection->n_incoming);
}
/**
* Checks whether there are messages in the outgoing message queue.
* Called with connection lock held.
*
* @param connection the connection.
* @returns #TRUE if the outgoing queue is non-empty.
*/
dbus_bool_t
_dbus_connection_has_messages_to_send_unlocked (DBusConnection *connection)
{
HAVE_LOCK_CHECK (connection);
return connection->outgoing_messages != NULL;
}
/**
* Checks whether there are messages in the outgoing message queue.
* Use dbus_connection_flush() to block until all outgoing
* messages have been written to the underlying transport
* (such as a socket).
*
* @param connection the connection.
* @returns #TRUE if the outgoing queue is non-empty.
*/
dbus_bool_t
dbus_connection_has_messages_to_send (DBusConnection *connection)
{
dbus_bool_t v;
_dbus_return_val_if_fail (connection != NULL, FALSE);
CONNECTION_LOCK (connection);
v = _dbus_connection_has_messages_to_send_unlocked (connection);
CONNECTION_UNLOCK (connection);
return v;
}
/**
* Gets the next outgoing message. The message remains in the
* queue, and the caller does not own a reference to it.
*
* @param connection the connection.
* @returns the message to be sent.
*/
DBusMessage*
_dbus_connection_get_message_to_send (DBusConnection *connection)
{
HAVE_LOCK_CHECK (connection);
return _dbus_list_get_last (&connection->outgoing_messages);
}
/**
* Notifies the connection that a message has been sent, so the
* message can be removed from the outgoing queue.
* Called with the connection lock held.
*
* @param connection the connection.
* @param message the message that was sent.
*/
void
_dbus_connection_message_sent_unlocked (DBusConnection *connection,
DBusMessage *message)
{
DBusList *link;
HAVE_LOCK_CHECK (connection);
/* This can be called before we even complete authentication, since
* it's called on disconnect to clean up the outgoing queue.
* It's also called as we successfully send each message.
*/
link = _dbus_list_get_last_link (&connection->outgoing_messages);
_dbus_assert (link != NULL);
_dbus_assert (link->data == message);
_dbus_list_unlink (&connection->outgoing_messages,
link);
_dbus_list_prepend_link (&connection->expired_messages, link);
connection->n_outgoing -= 1;
_dbus_verbose ("Message %p (%s %s %s %s '%s') removed from outgoing queue %p, %d left to send\n",
message,
dbus_message_type_to_string (dbus_message_get_type (message)),
dbus_message_get_path (message) ?
dbus_message_get_path (message) :
"no path",
dbus_message_get_interface (message) ?
dbus_message_get_interface (message) :
"no interface",
dbus_message_get_member (message) ?
dbus_message_get_member (message) :
"no member",
dbus_message_get_signature (message),
connection, connection->n_outgoing);
/* It's OK that in principle we call the notify function, because for the
* outgoing limit, there isn't one */
_dbus_message_remove_counter (message, connection->outgoing_counter);
/* The message will actually be unreffed when we unlock */
}
/** Function to be called in protected_change_watch() with refcount held */
typedef dbus_bool_t (* DBusWatchAddFunction) (DBusWatchList *list,
DBusWatch *watch);
/** Function to be called in protected_change_watch() with refcount held */
typedef void (* DBusWatchRemoveFunction) (DBusWatchList *list,
DBusWatch *watch);
/** Function to be called in protected_change_watch() with refcount held */
typedef void (* DBusWatchToggleFunction) (DBusWatchList *list,
DBusWatch *watch,
dbus_bool_t enabled);
static dbus_bool_t
protected_change_watch (DBusConnection *connection,
DBusWatch *watch,
DBusWatchAddFunction add_function,
DBusWatchRemoveFunction remove_function,
DBusWatchToggleFunction toggle_function,
dbus_bool_t enabled)
{
dbus_bool_t retval;
HAVE_LOCK_CHECK (connection);
/* The original purpose of protected_change_watch() was to hold a
* ref on the connection while dropping the connection lock, then
* calling out to the app. This was a broken hack that did not
* work, since the connection was in a hosed state (no WatchList
* field) while calling out.
*
* So for now we'll just keep the lock while calling out. This means
* apps are not allowed to call DBusConnection methods inside a
* watch function or they will deadlock.
*
* The "real fix" is to use the _and_unlock() pattern found
* elsewhere in the code, to defer calling out to the app until
* we're about to drop locks and return flow of control to the app
* anyway.
*
* See http://lists.freedesktop.org/archives/dbus/2007-July/thread.html#8144
*/
if (connection->watches)
{
if (add_function)
retval = (* add_function) (connection->watches, watch);
else if (remove_function)
{
retval = TRUE;
(* remove_function) (connection->watches, watch);
}
else
{
retval = TRUE;
(* toggle_function) (connection->watches, watch, enabled);
}
return retval;
}
else
return FALSE;
}
/**
* Adds a watch using the connection's DBusAddWatchFunction if
* available. Otherwise records the watch to be added when said
* function is available. Also re-adds the watch if the
* DBusAddWatchFunction changes. May fail due to lack of memory.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param watch the watch to add.
* @returns #TRUE on success.
*/
dbus_bool_t
_dbus_connection_add_watch_unlocked (DBusConnection *connection,
DBusWatch *watch)
{
return protected_change_watch (connection, watch,
_dbus_watch_list_add_watch,
NULL, NULL, FALSE);
}
/**
* Removes a watch using the connection's DBusRemoveWatchFunction
* if available. It's an error to call this function on a watch
* that was not previously added.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param watch the watch to remove.
*/
void
_dbus_connection_remove_watch_unlocked (DBusConnection *connection,
DBusWatch *watch)
{
protected_change_watch (connection, watch,
NULL,
_dbus_watch_list_remove_watch,
NULL, FALSE);
}
/**
* Toggles a watch and notifies app via connection's
* DBusWatchToggledFunction if available. It's an error to call this
* function on a watch that was not previously added.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param watch the watch to toggle.
* @param enabled whether to enable or disable
*/
void
_dbus_connection_toggle_watch_unlocked (DBusConnection *connection,
DBusWatch *watch,
dbus_bool_t enabled)
{
_dbus_assert (watch != NULL);
protected_change_watch (connection, watch,
NULL, NULL,
_dbus_watch_list_toggle_watch,
enabled);
}
/** Function to be called in protected_change_timeout() with refcount held */
typedef dbus_bool_t (* DBusTimeoutAddFunction) (DBusTimeoutList *list,
DBusTimeout *timeout);
/** Function to be called in protected_change_timeout() with refcount held */
typedef void (* DBusTimeoutRemoveFunction) (DBusTimeoutList *list,
DBusTimeout *timeout);
/** Function to be called in protected_change_timeout() with refcount held */
typedef void (* DBusTimeoutToggleFunction) (DBusTimeoutList *list,
DBusTimeout *timeout,
dbus_bool_t enabled);
static dbus_bool_t
protected_change_timeout (DBusConnection *connection,
DBusTimeout *timeout,
DBusTimeoutAddFunction add_function,
DBusTimeoutRemoveFunction remove_function,
DBusTimeoutToggleFunction toggle_function,
dbus_bool_t enabled)
{
dbus_bool_t retval;
HAVE_LOCK_CHECK (connection);
/* The original purpose of protected_change_timeout() was to hold a
* ref on the connection while dropping the connection lock, then
* calling out to the app. This was a broken hack that did not
* work, since the connection was in a hosed state (no TimeoutList
* field) while calling out.
*
* So for now we'll just keep the lock while calling out. This means
* apps are not allowed to call DBusConnection methods inside a
* timeout function or they will deadlock.
*
* The "real fix" is to use the _and_unlock() pattern found
* elsewhere in the code, to defer calling out to the app until
* we're about to drop locks and return flow of control to the app
* anyway.
*
* See http://lists.freedesktop.org/archives/dbus/2007-July/thread.html#8144
*/
if (connection->timeouts)
{
if (add_function)
retval = (* add_function) (connection->timeouts, timeout);
else if (remove_function)
{
retval = TRUE;
(* remove_function) (connection->timeouts, timeout);
}
else
{
retval = TRUE;
(* toggle_function) (connection->timeouts, timeout, enabled);
}
return retval;
}
else
return FALSE;
}
/**
* Adds a timeout using the connection's DBusAddTimeoutFunction if
* available. Otherwise records the timeout to be added when said
* function is available. Also re-adds the timeout if the
* DBusAddTimeoutFunction changes. May fail due to lack of memory.
* The timeout will fire repeatedly until removed.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param timeout the timeout to add.
* @returns #TRUE on success.
*/
dbus_bool_t
_dbus_connection_add_timeout_unlocked (DBusConnection *connection,
DBusTimeout *timeout)
{
return protected_change_timeout (connection, timeout,
_dbus_timeout_list_add_timeout,
NULL, NULL, FALSE);
}
/**
* Removes a timeout using the connection's DBusRemoveTimeoutFunction
* if available. It's an error to call this function on a timeout
* that was not previously added.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param timeout the timeout to remove.
*/
void
_dbus_connection_remove_timeout_unlocked (DBusConnection *connection,
DBusTimeout *timeout)
{
protected_change_timeout (connection, timeout,
NULL,
_dbus_timeout_list_remove_timeout,
NULL, FALSE);
}
/**
* Toggles a timeout and notifies app via connection's
* DBusTimeoutToggledFunction if available. It's an error to call this
* function on a timeout that was not previously added.
* Connection lock should be held when calling this.
*
* @param connection the connection.
* @param timeout the timeout to toggle.
* @param enabled whether to enable or disable
*/
void
_dbus_connection_toggle_timeout_unlocked (DBusConnection *connection,
DBusTimeout *timeout,
dbus_bool_t enabled)
{
protected_change_timeout (connection, timeout,
NULL, NULL,
_dbus_timeout_list_toggle_timeout,
enabled);
}
static dbus_bool_t
_dbus_connection_attach_pending_call_unlocked (DBusConnection *connection,
DBusPendingCall *pending)
{
dbus_uint32_t reply_serial;
DBusTimeout *timeout;
HAVE_LOCK_CHECK (connection);
reply_serial = _dbus_pending_call_get_reply_serial_unlocked (pending);
_dbus_assert (reply_serial != 0);
timeout = _dbus_pending_call_get_timeout_unlocked (pending);
if (timeout)
{
if (!_dbus_connection_add_timeout_unlocked (connection, timeout))
return FALSE;
if (!_dbus_hash_table_insert_int (connection->pending_replies,
reply_serial,
pending))
{
_dbus_connection_remove_timeout_unlocked (connection, timeout);
_dbus_pending_call_set_timeout_added_unlocked (pending, FALSE);
HAVE_LOCK_CHECK (connection);
return FALSE;
}
_dbus_pending_call_set_timeout_added_unlocked (pending, TRUE);
}
else
{
if (!_dbus_hash_table_insert_int (connection->pending_replies,
reply_serial,
pending))
{
HAVE_LOCK_CHECK (connection);
return FALSE;
}
}
_dbus_pending_call_ref_unlocked (pending);
HAVE_LOCK_CHECK (connection);
return TRUE;
}
static void
free_pending_call_on_hash_removal (void *data)
{
DBusPendingCall *pending;
DBusConnection *connection;
if (data == NULL)
return;
pending = data;
connection = _dbus_pending_call_get_connection_unlocked (pending);
HAVE_LOCK_CHECK (connection);
if (_dbus_pending_call_is_timeout_added_unlocked (pending))
{
_dbus_connection_remove_timeout_unlocked (connection,
_dbus_pending_call_get_timeout_unlocked (pending));
_dbus_pending_call_set_timeout_added_unlocked (pending, FALSE);
}
/* FIXME 1.0? this is sort of dangerous and undesirable to drop the lock
* here, but the pending call finalizer could in principle call out to
* application code so we pretty much have to... some larger code reorg
* might be needed.
*/
_dbus_connection_ref_unlocked (connection);
_dbus_pending_call_unref_and_unlock (pending);
CONNECTION_LOCK (connection);
_dbus_connection_unref_unlocked (connection);
}
static void
_dbus_connection_detach_pending_call_unlocked (DBusConnection *connection,
DBusPendingCall *pending)
{
/* This ends up unlocking to call the pending call finalizer, which is unexpected to
* say the least.
*/
_dbus_hash_table_remove_int (connection->pending_replies,
_dbus_pending_call_get_reply_serial_unlocked (pending));
}
static void
_dbus_connection_detach_pending_call_and_unlock (DBusConnection *connection,
DBusPendingCall *pending)
{
/* The idea here is to avoid finalizing the pending call
* with the lock held, since there's a destroy notifier
* in pending call that goes out to application code.
*
* There's an extra unlock inside the hash table
* "free pending call" function FIXME...
*/
_dbus_pending_call_ref_unlocked (pending);
_dbus_hash_table_remove_int (connection->pending_replies,
_dbus_pending_call_get_reply_serial_unlocked (pending));
if (_dbus_pending_call_is_timeout_added_unlocked (pending))
_dbus_connection_remove_timeout_unlocked (connection,
_dbus_pending_call_get_timeout_unlocked (pending));
_dbus_pending_call_set_timeout_added_unlocked (pending, FALSE);
_dbus_pending_call_unref_and_unlock (pending);
}
/**
* Removes a pending call from the connection, such that
* the pending reply will be ignored. May drop the last
* reference to the pending call.
*
* @param connection the connection
* @param pending the pending call
*/
void
_dbus_connection_remove_pending_call (DBusConnection *connection,
DBusPendingCall *pending)
{
CONNECTION_LOCK (connection);
_dbus_connection_detach_pending_call_and_unlock (connection, pending);
}
/**
* Acquire the transporter I/O path. This must be done before
* doing any I/O in the transporter. May sleep and drop the
* IO path mutex while waiting for the I/O path.
*
* @param connection the connection.
* @param timeout_milliseconds maximum blocking time, or -1 for no limit.
* @returns TRUE if the I/O path was acquired.
*/
static dbus_bool_t
_dbus_connection_acquire_io_path (DBusConnection *connection,
int timeout_milliseconds)
{
dbus_bool_t we_acquired;
HAVE_LOCK_CHECK (connection);
/* We don't want the connection to vanish */
_dbus_connection_ref_unlocked (connection);
/* We will only touch io_path_acquired which is protected by our mutex */
CONNECTION_UNLOCK (connection);
_dbus_verbose ("locking io_path_mutex\n");
_dbus_cmutex_lock (connection->io_path_mutex);
_dbus_verbose ("start connection->io_path_acquired = %d timeout = %d\n",
connection->io_path_acquired, timeout_milliseconds);
we_acquired = FALSE;
if (connection->io_path_acquired)
{
if (timeout_milliseconds != -1)
{
_dbus_verbose ("waiting %d for IO path to be acquirable\n",
timeout_milliseconds);
if (!_dbus_condvar_wait_timeout (connection->io_path_cond,
connection->io_path_mutex,
timeout_milliseconds))
{
/* We timed out before anyone signaled. */
/* (writing the loop to handle the !timedout case by
* waiting longer if needed is a pain since dbus
* wraps pthread_cond_timedwait to take a relative
* time instead of absolute, something kind of stupid
* on our part. for now it doesn't matter, we will just
* end up back here eventually.)
*/
}
}
else
{
while (connection->io_path_acquired)
{
_dbus_verbose ("waiting for IO path to be acquirable\n");
_dbus_condvar_wait (connection->io_path_cond,
connection->io_path_mutex);
}
}
}
if (!connection->io_path_acquired)
{
we_acquired = TRUE;
connection->io_path_acquired = TRUE;
}
_dbus_verbose ("end connection->io_path_acquired = %d we_acquired = %d\n",
connection->io_path_acquired, we_acquired);
_dbus_verbose ("unlocking io_path_mutex\n");
_dbus_cmutex_unlock (connection->io_path_mutex);
CONNECTION_LOCK (connection);
HAVE_LOCK_CHECK (connection);
_dbus_connection_unref_unlocked (connection);
return we_acquired;
}
/**
* Release the I/O path when you're done with it. Only call
* after you've acquired the I/O. Wakes up at most one thread
* currently waiting to acquire the I/O path.
*
* @param connection the connection.
*/
static void
_dbus_connection_release_io_path (DBusConnection *connection)
{
HAVE_LOCK_CHECK (connection);
_dbus_verbose ("locking io_path_mutex\n");
_dbus_cmutex_lock (connection->io_path_mutex);
_dbus_assert (connection->io_path_acquired);
_dbus_verbose ("start connection->io_path_acquired = %d\n",
connection->io_path_acquired);
connection->io_path_acquired = FALSE;
_dbus_condvar_wake_one (connection->io_path_cond);
_dbus_verbose ("unlocking io_path_mutex\n");
_dbus_cmutex_unlock (connection->io_path_mutex);
}
/**
* Queues incoming messages and sends outgoing messages for this
* connection, optionally blocking in the process. Each call to
* _dbus_connection_do_iteration_unlocked() will call select() or poll() one
* time and then read or write data if possible.
*
* The purpose of this function is to be able to flush outgoing
* messages or queue up incoming messages without returning
* control to the application and causing reentrancy weirdness.
*
* The flags parameter allows you to specify whether to
* read incoming messages, write outgoing messages, or both,
* and whether to block if no immediate action is possible.
*
* The timeout_milliseconds parameter does nothing unless the
* iteration is blocking.
*
* If there are no outgoing messages and DBUS_ITERATION_DO_READING
* wasn't specified, then it's impossible to block, even if
* you specify DBUS_ITERATION_BLOCK; in that case the function
* returns immediately.
*
* If pending is not NULL then a check is made if the pending call
* is completed after the io path has been required. If the call
* has been completed nothing is done. This must be done since
* the _dbus_connection_acquire_io_path releases the connection
* lock for a while.
*
* Called with connection lock held.
*
* @param connection the connection.
* @param pending the pending call that should be checked or NULL
* @param flags iteration flags.
* @param timeout_milliseconds maximum blocking time, or -1 for no limit.
*/
void
_dbus_connection_do_iteration_unlocked (DBusConnection *connection,
DBusPendingCall *pending,
unsigned int flags,
int timeout_milliseconds)
{
_dbus_verbose ("start\n");
HAVE_LOCK_CHECK (connection);
if (connection->n_outgoing == 0)
flags &= ~DBUS_ITERATION_DO_WRITING;
if (_dbus_connection_acquire_io_path (connection,
(flags & DBUS_ITERATION_BLOCK) ? timeout_milliseconds : 0))
{
HAVE_LOCK_CHECK (connection);
if ( (pending != NULL) && _dbus_pending_call_get_completed_unlocked(pending))
{
_dbus_verbose ("pending call completed while acquiring I/O path");
}
else if ( (pending != NULL) &&
_dbus_connection_peek_for_reply_unlocked (connection,
_dbus_pending_call_get_reply_serial_unlocked (pending)))
{
_dbus_verbose ("pending call completed while acquiring I/O path (reply found in queue)");
}
else
{
_dbus_transport_do_iteration (connection->transport,
flags, timeout_milliseconds);
}
_dbus_connection_release_io_path (connection);
}
HAVE_LOCK_CHECK (connection);
_dbus_verbose ("end\n");
}
/**
* Creates a new connection for the given transport. A transport
* represents a message stream that uses some concrete mechanism, such
* as UNIX domain sockets. May return #NULL if insufficient
* memory exists to create the connection.
*
* @param transport the transport.
* @returns the new connection, or #NULL on failure.
*/
DBusConnection*
_dbus_connection_new_for_transport (DBusTransport *transport)
{
DBusConnection *connection;
DBusWatchList *watch_list;
DBusTimeoutList *timeout_list;
DBusHashTable *pending_replies;
DBusList *disconnect_link;
DBusMessage *disconnect_message;
DBusCounter *outgoing_counter;
DBusObjectTree *objects;
watch_list = NULL;
connection = NULL;
pending_replies = NULL;
timeout_list = NULL;
disconnect_link = NULL;
disconnect_message = NULL;
outgoing_counter = NULL;
objects = NULL;
watch_list = _dbus_watch_list_new ();
if (watch_list == NULL)
goto error;
timeout_list = _dbus_timeout_list_new ();
if (timeout_list == NULL)
goto error;
pending_replies =
_dbus_hash_table_new (DBUS_HASH_INT,
NULL,
(DBusFreeFunction)free_pending_call_on_hash_removal);
if (pending_replies == NULL)
goto error;
connection = dbus_new0 (DBusConnection, 1);
if (connection == NULL)
goto error;
_dbus_rmutex_new_at_location (&connection->mutex);
if (connection->mutex == NULL)
goto error;
_dbus_cmutex_new_at_location (&connection->io_path_mutex);
if (connection->io_path_mutex == NULL)
goto error;
_dbus_cmutex_new_at_location (&connection->dispatch_mutex);
if (connection->dispatch_mutex == NULL)
goto error;
_dbus_condvar_new_at_location (&connection->dispatch_cond);
if (connection->dispatch_cond == NULL)
goto error;
_dbus_condvar_new_at_location (&connection->io_path_cond);
if (connection->io_path_cond == NULL)
goto error;
_dbus_rmutex_new_at_location (&connection->slot_mutex);
if (connection->slot_mutex == NULL)
goto error;
disconnect_message = dbus_message_new_signal (DBUS_PATH_LOCAL,
DBUS_INTERFACE_LOCAL,
"Disconnected");
if (disconnect_message == NULL)
goto error;
disconnect_link = _dbus_list_alloc_link (disconnect_message);
if (disconnect_link == NULL)
goto error;
outgoing_counter = _dbus_counter_new ();
if (outgoing_counter == NULL)
goto error;
objects = _dbus_object_tree_new (connection);
if (objects == NULL)
goto error;
if (_dbus_modify_sigpipe)
_dbus_disable_sigpipe ();
/* initialized to 0: use atomic op to avoid mixing atomic and non-atomic */
_dbus_atomic_inc (&connection->refcount);
connection->transport = transport;
connection->watches = watch_list;
connection->timeouts = timeout_list;
connection->pending_replies = pending_replies;
connection->outgoing_counter = outgoing_counter;
connection->filter_list = NULL;
connection->last_dispatch_status = DBUS_DISPATCH_COMPLETE; /* so we're notified first time there's data */
connection->objects = objects;
connection->exit_on_disconnect = FALSE;
connection->shareable = FALSE;
connection->route_peer_messages = FALSE;
connection->disconnected_message_arrived = FALSE;
connection->disconnected_message_processed = FALSE;
#ifndef DBUS_DISABLE_CHECKS
connection->generation = _dbus_current_generation;
#endif
_dbus_data_slot_list_init (&connection->slot_list);
connection->client_serial = 1;
connection->disconnect_message_link = disconnect_link;
CONNECTION_LOCK (connection);
if (!_dbus_transport_set_connection (transport, connection))
{
CONNECTION_UNLOCK (connection);
goto error;
}
_dbus_transport_ref (transport);
CONNECTION_UNLOCK (connection);
_dbus_connection_trace_ref (connection, 0, 1, "new_for_transport");
return connection;
error:
if (disconnect_message != NULL)
dbus_message_unref (disconnect_message);
if (disconnect_link != NULL)
_dbus_list_free_link (disconnect_link);
if (connection != NULL)
{
_dbus_condvar_free_at_location (&connection->io_path_cond);
_dbus_condvar_free_at_location (&connection->dispatch_cond);
_dbus_rmutex_free_at_location (&connection->mutex);
_dbus_cmutex_free_at_location (&connection->io_path_mutex);
_dbus_cmutex_free_at_location (&connection->dispatch_mutex);
_dbus_rmutex_free_at_location (&connection->slot_mutex);
dbus_free (connection);
}
if (pending_replies)
_dbus_hash_table_unref (pending_replies);
if (watch_list)
_dbus_watch_list_free (watch_list);
if (timeout_list)
_dbus_timeout_list_free (timeout_list);
if (outgoing_counter)
_dbus_counter_unref (outgoing_counter);
if (objects)
_dbus_object_tree_unref (objects);
return NULL;
}
/**
* Increments the reference count of a DBusConnection.
* Requires that the caller already holds the connection lock.
*
* @param connection the connection.
* @returns the connection.
*/
DBusConnection *
_dbus_connection_ref_unlocked (DBusConnection *connection)
{
dbus_int32_t old_refcount;
_dbus_assert (connection != NULL);
_dbus_assert (connection->generation == _dbus_current_generation);
HAVE_LOCK_CHECK (connection);
old_refcount = _dbus_atomic_inc (&connection->refcount);
_dbus_connection_trace_ref (connection, old_refcount, old_refcount + 1,
"ref_unlocked");
return connection;
}
/**
* Decrements the reference count of a DBusConnection.
* Requires that the caller already holds the connection lock.
*
* @param connection the connection.
*/
void
_dbus_connection_unref_unlocked (DBusConnection *connection)
{
dbus_int32_t old_refcount;
HAVE_LOCK_CHECK (connection);
_dbus_assert (connection != NULL);
old_refcount = _dbus_atomic_dec (&connection->refcount);
_dbus_connection_trace_ref (connection, old_refcount, old_refcount - 1,
"unref_unlocked");
if (old_refcount == 1)
_dbus_connection_last_unref (connection);
}
static dbus_uint32_t
_dbus_connection_get_next_client_serial (DBusConnection *connection)
{
dbus_uint32_t serial;
serial = connection->client_serial++;
if (connection->client_serial == 0)
connection->client_serial = 1;
return serial;
}
/**
* A callback for use with dbus_watch_new() to create a DBusWatch.
*
* @todo This is basically a hack - we could delete _dbus_transport_handle_watch()
* and the virtual handle_watch in DBusTransport if we got rid of it.
* The reason this is some work is threading, see the _dbus_connection_handle_watch()
* implementation.
*
* @param watch the watch.
* @param condition the current condition of the file descriptors being watched.
* @param data must be a pointer to a #DBusConnection
* @returns #FALSE if the IO condition may not have been fully handled due to lack of memory
*/
dbus_bool_t
_dbus_connection_handle_watch (DBusWatch *watch,
unsigned int condition,
void *data)
{
DBusConnection *connection;
dbus_bool_t retval;
DBusDispatchStatus status;
connection = data;
_dbus_verbose ("start\n");
CONNECTION_LOCK (connection);
if (!_dbus_connection_acquire_io_path (connection, 1))
{
/* another thread is handling the message */
CONNECTION_UNLOCK (connection);
return TRUE;
}
HAVE_LOCK_CHECK (connection);
retval = _dbus_transport_handle_watch (connection->transport,
watch, condition);
_dbus_connection_release_io_path (connection);
HAVE_LOCK_CHECK (connection);
_dbus_verbose ("middle\n");
status = _dbus_connection_get_dispatch_status_unlocked (connection);
/* this calls out to user code */
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
_dbus_verbose ("end\n");
return retval;
}
_DBUS_DEFINE_GLOBAL_LOCK (shared_connections);
static DBusHashTable *shared_connections = NULL;
static DBusList *shared_connections_no_guid = NULL;
static void
close_connection_on_shutdown (DBusConnection *connection)
{
DBusMessage *message;
dbus_connection_ref (connection);
_dbus_connection_close_possibly_shared (connection);
/* Churn through to the Disconnected message */
while ((message = dbus_connection_pop_message (connection)))
{
dbus_message_unref (message);
}
dbus_connection_unref (connection);
}
static void
shared_connections_shutdown (void *data)
{
int n_entries;
_DBUS_LOCK (shared_connections);
/* This is a little bit unpleasant... better ideas? */
while ((n_entries = _dbus_hash_table_get_n_entries (shared_connections)) > 0)
{
DBusConnection *connection;
DBusHashIter iter;
_dbus_hash_iter_init (shared_connections, &iter);
_dbus_hash_iter_next (&iter);
connection = _dbus_hash_iter_get_value (&iter);
_DBUS_UNLOCK (shared_connections);
close_connection_on_shutdown (connection);
_DBUS_LOCK (shared_connections);
/* The connection should now be dead and not in our hash ... */
_dbus_assert (_dbus_hash_table_get_n_entries (shared_connections) < n_entries);
}
_dbus_assert (_dbus_hash_table_get_n_entries (shared_connections) == 0);
_dbus_hash_table_unref (shared_connections);
shared_connections = NULL;
if (shared_connections_no_guid != NULL)
{
DBusConnection *connection;
connection = _dbus_list_pop_first (&shared_connections_no_guid);
while (connection != NULL)
{
_DBUS_UNLOCK (shared_connections);
close_connection_on_shutdown (connection);
_DBUS_LOCK (shared_connections);
connection = _dbus_list_pop_first (&shared_connections_no_guid);
}
}
shared_connections_no_guid = NULL;
_DBUS_UNLOCK (shared_connections);
}
static dbus_bool_t
connection_lookup_shared (DBusAddressEntry *entry,
DBusConnection **result)
{
_dbus_verbose ("checking for existing connection\n");
*result = NULL;
_DBUS_LOCK (shared_connections);
if (shared_connections == NULL)
{
_dbus_verbose ("creating shared_connections hash table\n");
shared_connections = _dbus_hash_table_new (DBUS_HASH_STRING,
dbus_free,
NULL);
if (shared_connections == NULL)
{
_DBUS_UNLOCK (shared_connections);
return FALSE;
}
if (!_dbus_register_shutdown_func (shared_connections_shutdown, NULL))
{
_dbus_hash_table_unref (shared_connections);
shared_connections = NULL;
_DBUS_UNLOCK (shared_connections);
return FALSE;
}
_dbus_verbose (" successfully created shared_connections\n");
_DBUS_UNLOCK (shared_connections);
return TRUE; /* no point looking up in the hash we just made */
}
else
{
const char *guid;
guid = dbus_address_entry_get_value (entry, "guid");
if (guid != NULL)
{
DBusConnection *connection;
connection = _dbus_hash_table_lookup_string (shared_connections,
guid);
if (connection)
{
/* The DBusConnection can't be finalized without taking
* the shared_connections lock to remove it from the
* hash. So it's safe to ref the connection here.
* However, it may be disconnected if the Disconnected
* message hasn't been processed yet, in which case we
* want to pretend it isn't in the hash and avoid
* returning it.
*
* The idea is to avoid ever returning a disconnected connection
* from dbus_connection_open(). We could just synchronously
* drop our shared ref to the connection on connection disconnect,
* and then assert here that the connection is connected, but
* that causes reentrancy headaches.
*/
CONNECTION_LOCK (connection);
if (_dbus_connection_get_is_connected_unlocked (connection))
{
_dbus_connection_ref_unlocked (connection);
*result = connection;
_dbus_verbose ("looked up existing connection to server guid %s\n",
guid);
}
else
{
_dbus_verbose ("looked up existing connection to server guid %s but it was disconnected so ignoring it\n",
guid);
}
CONNECTION_UNLOCK (connection);
}
}
_DBUS_UNLOCK (shared_connections);
return TRUE;
}
}
static dbus_bool_t
connection_record_shared_unlocked (DBusConnection *connection,
const char *guid)
{
char *guid_key;
char *guid_in_connection;
HAVE_LOCK_CHECK (connection);
_dbus_assert (connection->server_guid == NULL);
_dbus_assert (connection->shareable);
/* get a hard ref on this connection, even if
* we won't in fact store it in the hash, we still
* need to hold a ref on it until it's disconnected.
*/
_dbus_connection_ref_unlocked (connection);
if (guid == NULL)
{
_DBUS_LOCK (shared_connections);
if (!_dbus_list_prepend (&shared_connections_no_guid, connection))
{
_DBUS_UNLOCK (shared_connections);
return FALSE;
}
_DBUS_UNLOCK (shared_connections);
return TRUE; /* don't store in the hash */
}
/* A separate copy of the key is required in the hash table, because
* we don't have a lock on the connection when we are doing a hash
* lookup.
*/
guid_key = _dbus_strdup (guid);
if (guid_key == NULL)
return FALSE;
guid_in_connection = _dbus_strdup (guid);
if (guid_in_connection == NULL)
{
dbus_free (guid_key);
return FALSE;
}
_DBUS_LOCK (shared_connections);
_dbus_assert (shared_connections != NULL);
if (!_dbus_hash_table_insert_string (shared_connections,
guid_key, connection))
{
dbus_free (guid_key);
dbus_free (guid_in_connection);
_DBUS_UNLOCK (shared_connections);
return FALSE;
}
connection->server_guid = guid_in_connection;
_dbus_verbose ("stored connection to %s to be shared\n",
connection->server_guid);
_DBUS_UNLOCK (shared_connections);
_dbus_assert (connection->server_guid != NULL);
return TRUE;
}
static void
connection_forget_shared_unlocked (DBusConnection *connection)
{
HAVE_LOCK_CHECK (connection);
if (!connection->shareable)
return;
_DBUS_LOCK (shared_connections);
if (connection->server_guid != NULL)
{
_dbus_verbose ("dropping connection to %s out of the shared table\n",
connection->server_guid);
if (!_dbus_hash_table_remove_string (shared_connections,
connection->server_guid))
_dbus_assert_not_reached ("connection was not in the shared table");
dbus_free (connection->server_guid);
connection->server_guid = NULL;
}
else
{
_dbus_list_remove (&shared_connections_no_guid, connection);
}
_DBUS_UNLOCK (shared_connections);
/* remove our reference held on all shareable connections */
_dbus_connection_unref_unlocked (connection);
}
static DBusConnection*
connection_try_from_address_entry (DBusAddressEntry *entry,
DBusError *error)
{
DBusTransport *transport;
DBusConnection *connection;
transport = _dbus_transport_open (entry, error);
if (transport == NULL)
{
_DBUS_ASSERT_ERROR_IS_SET (error);
return NULL;
}
connection = _dbus_connection_new_for_transport (transport);
_dbus_transport_unref (transport);
if (connection == NULL)
{
_DBUS_SET_OOM (error);
return NULL;
}
#ifndef DBUS_DISABLE_CHECKS
_dbus_assert (!connection->have_connection_lock);
#endif
return connection;
}
/*
* If the shared parameter is true, then any existing connection will
* be used (and if a new connection is created, it will be available
* for use by others). If the shared parameter is false, a new
* connection will always be created, and the new connection will
* never be returned to other callers.
*
* @param address the address
* @param shared whether the connection is shared or private
* @param error error return
* @returns the connection or #NULL on error
*/
static DBusConnection*
_dbus_connection_open_internal (const char *address,
dbus_bool_t shared,
DBusError *error)
{
DBusConnection *connection;
DBusAddressEntry **entries;
DBusError tmp_error = DBUS_ERROR_INIT;
DBusError first_error = DBUS_ERROR_INIT;
int len, i;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
_dbus_verbose ("opening %s connection to: %s\n",
shared ? "shared" : "private", address);
if (!dbus_parse_address (address, &entries, &len, error))
return NULL;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
connection = NULL;
for (i = 0; i < len; i++)
{
if (shared)
{
if (!connection_lookup_shared (entries[i], &connection))
_DBUS_SET_OOM (&tmp_error);
}
if (connection == NULL)
{
connection = connection_try_from_address_entry (entries[i],
&tmp_error);
if (connection != NULL && shared)
{
const char *guid;
connection->shareable = TRUE;
/* guid may be NULL */
guid = dbus_address_entry_get_value (entries[i], "guid");
CONNECTION_LOCK (connection);
if (!connection_record_shared_unlocked (connection, guid))
{
_DBUS_SET_OOM (&tmp_error);
_dbus_connection_close_possibly_shared_and_unlock (connection);
dbus_connection_unref (connection);
connection = NULL;
}
else
CONNECTION_UNLOCK (connection);
}
}
if (connection)
break;
_DBUS_ASSERT_ERROR_IS_SET (&tmp_error);
if (i == 0)
dbus_move_error (&tmp_error, &first_error);
else
dbus_error_free (&tmp_error);
}
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
_DBUS_ASSERT_ERROR_IS_CLEAR (&tmp_error);
if (connection == NULL)
{
_DBUS_ASSERT_ERROR_IS_SET (&first_error);
dbus_move_error (&first_error, error);
}
else
dbus_error_free (&first_error);
dbus_address_entries_free (entries);
return connection;
}
/**
* Closes a shared OR private connection, while dbus_connection_close() can
* only be used on private connections. Should only be called by the
* dbus code that owns the connection - an owner must be known,
* the open/close state is like malloc/free, not like ref/unref.
*
* @param connection the connection
*/
void
_dbus_connection_close_possibly_shared (DBusConnection *connection)
{
_dbus_assert (connection != NULL);
_dbus_assert (connection->generation == _dbus_current_generation);
CONNECTION_LOCK (connection);
_dbus_connection_close_possibly_shared_and_unlock (connection);
}
static DBusPreallocatedSend*
_dbus_connection_preallocate_send_unlocked (DBusConnection *connection)
{
DBusPreallocatedSend *preallocated;
HAVE_LOCK_CHECK (connection);
_dbus_assert (connection != NULL);
preallocated = dbus_new (DBusPreallocatedSend, 1);
if (preallocated == NULL)
return NULL;
preallocated->queue_link = _dbus_list_alloc_link (NULL);
if (preallocated->queue_link == NULL)
goto failed_0;
preallocated->counter_link = _dbus_list_alloc_link (connection->outgoing_counter);
if (preallocated->counter_link == NULL)
goto failed_1;
_dbus_counter_ref (preallocated->counter_link->data);
preallocated->connection = connection;
return preallocated;
failed_1:
_dbus_list_free_link (preallocated->queue_link);
failed_0:
dbus_free (preallocated);
return NULL;
}
/* Called with lock held, does not update dispatch status */
static void
_dbus_connection_send_preallocated_unlocked_no_update (DBusConnection *connection,
DBusPreallocatedSend *preallocated,
DBusMessage *message,
dbus_uint32_t *client_serial)
{
dbus_uint32_t serial;
preallocated->queue_link->data = message;
_dbus_list_prepend_link (&connection->outgoing_messages,
preallocated->queue_link);
/* It's OK that we'll never call the notify function, because for the
* outgoing limit, there isn't one */
_dbus_message_add_counter_link (message,
preallocated->counter_link);
dbus_free (preallocated);
preallocated = NULL;
dbus_message_ref (message);
connection->n_outgoing += 1;
_dbus_verbose ("Message %p (%s %s %s %s '%s') for %s added to outgoing queue %p, %d pending to send\n",
message,
dbus_message_type_to_string (dbus_message_get_type (message)),
dbus_message_get_path (message) ?
dbus_message_get_path (message) :
"no path",
dbus_message_get_interface (message) ?
dbus_message_get_interface (message) :
"no interface",
dbus_message_get_member (message) ?
dbus_message_get_member (message) :
"no member",
dbus_message_get_signature (message),
dbus_message_get_destination (message) ?
dbus_message_get_destination (message) :
"null",
connection,
connection->n_outgoing);
if (dbus_message_get_serial (message) == 0)
{
serial = _dbus_connection_get_next_client_serial (connection);
dbus_message_set_serial (message, serial);
if (client_serial)
*client_serial = serial;
}
else
{
if (client_serial)
*client_serial = dbus_message_get_serial (message);
}
_dbus_verbose ("Message %p serial is %u\n",
message, dbus_message_get_serial (message));
dbus_message_lock (message);
/* Now we need to run an iteration to hopefully just write the messages
* out immediately, and otherwise get them queued up
*/
_dbus_connection_do_iteration_unlocked (connection,
NULL,
DBUS_ITERATION_DO_WRITING,
-1);
/* If stuff is still queued up, be sure we wake up the main loop */
if (connection->n_outgoing > 0)
_dbus_connection_wakeup_mainloop (connection);
}
static void
_dbus_connection_send_preallocated_and_unlock (DBusConnection *connection,
DBusPreallocatedSend *preallocated,
DBusMessage *message,
dbus_uint32_t *client_serial)
{
DBusDispatchStatus status;
HAVE_LOCK_CHECK (connection);
_dbus_connection_send_preallocated_unlocked_no_update (connection,
preallocated,
message, client_serial);
_dbus_verbose ("middle\n");
status = _dbus_connection_get_dispatch_status_unlocked (connection);
/* this calls out to user code */
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
}
/**
* Like dbus_connection_send(), but assumes the connection
* is already locked on function entry, and unlocks before returning.
*
* @param connection the connection
* @param message the message to send
* @param client_serial return location for client serial of sent message
* @returns #FALSE on out-of-memory
*/
dbus_bool_t
_dbus_connection_send_and_unlock (DBusConnection *connection,
DBusMessage *message,
dbus_uint32_t *client_serial)
{
DBusPreallocatedSend *preallocated;
_dbus_assert (connection != NULL);
_dbus_assert (message != NULL);
preallocated = _dbus_connection_preallocate_send_unlocked (connection);
if (preallocated == NULL)
{
CONNECTION_UNLOCK (connection);
return FALSE;
}
_dbus_connection_send_preallocated_and_unlock (connection,
preallocated,
message,
client_serial);
return TRUE;
}
/**
* Used internally to handle the semantics of dbus_server_set_new_connection_function().
* If the new connection function does not ref the connection, we want to close it.
*
* A bit of a hack, probably the new connection function should have returned a value
* for whether to close, or should have had to close the connection itself if it
* didn't want it.
*
* But, this works OK as long as the new connection function doesn't do anything
* crazy like keep the connection around without ref'ing it.
*
* We have to lock the connection across refcount check and close in case
* the new connection function spawns a thread that closes and unrefs.
* In that case, if the app thread
* closes and unrefs first, we'll harmlessly close again; if the app thread
* still has the ref, we'll close and then the app will close harmlessly.
* If the app unrefs without closing, the app is broken since if the
* app refs from the new connection function it is supposed to also close.
*
* If we didn't atomically check the refcount and close with the lock held
* though, we could screw this up.
*
* @param connection the connection
*/
void
_dbus_connection_close_if_only_one_ref (DBusConnection *connection)
{
dbus_int32_t refcount;
CONNECTION_LOCK (connection);
refcount = _dbus_atomic_get (&connection->refcount);
/* The caller should have at least one ref */
_dbus_assert (refcount >= 1);
if (refcount == 1)
_dbus_connection_close_possibly_shared_and_unlock (connection);
else
CONNECTION_UNLOCK (connection);
}
/**
* When a function that blocks has been called with a timeout, and we
* run out of memory, the time to wait for memory is based on the
* timeout. If the caller was willing to block a long time we wait a
* relatively long time for memory, if they were only willing to block
* briefly then we retry for memory at a rapid rate.
*
* @timeout_milliseconds the timeout requested for blocking
*/
static void
_dbus_memory_pause_based_on_timeout (int timeout_milliseconds)
{
if (timeout_milliseconds == -1)
_dbus_sleep_milliseconds (1000);
else if (timeout_milliseconds < 100)
; /* just busy loop */
else if (timeout_milliseconds <= 1000)
_dbus_sleep_milliseconds (timeout_milliseconds / 3);
else
_dbus_sleep_milliseconds (1000);
}
static DBusMessage *
generate_local_error_message (dbus_uint32_t serial,
char *error_name,
char *error_msg)
{
DBusMessage *message;
message = dbus_message_new (DBUS_MESSAGE_TYPE_ERROR);
if (!message)
goto out;
if (!dbus_message_set_error_name (message, error_name))
{
dbus_message_unref (message);
message = NULL;
goto out;
}
dbus_message_set_no_reply (message, TRUE);
if (!dbus_message_set_reply_serial (message,
serial))
{
dbus_message_unref (message);
message = NULL;
goto out;
}
if (error_msg != NULL)
{
DBusMessageIter iter;
dbus_message_iter_init_append (message, &iter);
if (!dbus_message_iter_append_basic (&iter,
DBUS_TYPE_STRING,
&error_msg))
{
dbus_message_unref (message);
message = NULL;
goto out;
}
}
out:
return message;
}
/*
* Peek the incoming queue to see if we got reply for a specific serial
*/
static dbus_bool_t
_dbus_connection_peek_for_reply_unlocked (DBusConnection *connection,
dbus_uint32_t client_serial)
{
DBusList *link;
HAVE_LOCK_CHECK (connection);
link = _dbus_list_get_first_link (&connection->incoming_messages);
while (link != NULL)
{
DBusMessage *reply = link->data;
if (dbus_message_get_reply_serial (reply) == client_serial)
{
_dbus_verbose ("%s reply to %d found in queue\n", _DBUS_FUNCTION_NAME, client_serial);
return TRUE;
}
link = _dbus_list_get_next_link (&connection->incoming_messages, link);
}
return FALSE;
}
/* This is slightly strange since we can pop a message here without
* the dispatch lock.
*/
static DBusMessage*
check_for_reply_unlocked (DBusConnection *connection,
dbus_uint32_t client_serial)
{
DBusList *link;
HAVE_LOCK_CHECK (connection);
link = _dbus_list_get_first_link (&connection->incoming_messages);
while (link != NULL)
{
DBusMessage *reply = link->data;
if (dbus_message_get_reply_serial (reply) == client_serial)
{
_dbus_list_remove_link (&connection->incoming_messages, link);
connection->n_incoming -= 1;
return reply;
}
link = _dbus_list_get_next_link (&connection->incoming_messages, link);
}
return NULL;
}
static void
connection_timeout_and_complete_all_pending_calls_unlocked (DBusConnection *connection)
{
/* We can't iterate over the hash in the normal way since we'll be
* dropping the lock for each item. So we restart the
* iter each time as we drain the hash table.
*/
while (_dbus_hash_table_get_n_entries (connection->pending_replies) > 0)
{
DBusPendingCall *pending;
DBusHashIter iter;
_dbus_hash_iter_init (connection->pending_replies, &iter);
_dbus_hash_iter_next (&iter);
pending = _dbus_hash_iter_get_value (&iter);
_dbus_pending_call_ref_unlocked (pending);
_dbus_pending_call_queue_timeout_error_unlocked (pending,
connection);
if (_dbus_pending_call_is_timeout_added_unlocked (pending))
_dbus_connection_remove_timeout_unlocked (connection,
_dbus_pending_call_get_timeout_unlocked (pending));
_dbus_pending_call_set_timeout_added_unlocked (pending, FALSE);
_dbus_hash_iter_remove_entry (&iter);
_dbus_pending_call_unref_and_unlock (pending);
CONNECTION_LOCK (connection);
}
HAVE_LOCK_CHECK (connection);
}
static void
complete_pending_call_and_unlock (DBusConnection *connection,
DBusPendingCall *pending,
DBusMessage *message)
{
_dbus_pending_call_set_reply_unlocked (pending, message);
_dbus_pending_call_ref_unlocked (pending); /* in case there's no app with a ref held */
_dbus_connection_detach_pending_call_and_unlock (connection, pending);
/* Must be called unlocked since it invokes app callback */
_dbus_pending_call_complete (pending);
dbus_pending_call_unref (pending);
}
static dbus_bool_t
check_for_reply_and_update_dispatch_unlocked (DBusConnection *connection,
DBusPendingCall *pending)
{
DBusMessage *reply;
DBusDispatchStatus status;
reply = check_for_reply_unlocked (connection,
_dbus_pending_call_get_reply_serial_unlocked (pending));
if (reply != NULL)
{
_dbus_verbose ("checked for reply\n");
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): got reply\n");
complete_pending_call_and_unlock (connection, pending, reply);
dbus_message_unref (reply);
CONNECTION_LOCK (connection);
status = _dbus_connection_get_dispatch_status_unlocked (connection);
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
dbus_pending_call_unref (pending);
return TRUE;
}
return FALSE;
}
/**
* Blocks until a pending call times out or gets a reply.
*
* Does not re-enter the main loop or run filter/path-registered
* callbacks. The reply to the message will not be seen by
* filter callbacks.
*
* Returns immediately if pending call already got a reply.
*
* @todo could use performance improvements (it keeps scanning
* the whole message queue for example)
*
* @param pending the pending call we block for a reply on
*/
void
_dbus_connection_block_pending_call (DBusPendingCall *pending)
{
long start_tv_sec, start_tv_usec;
long tv_sec, tv_usec;
DBusDispatchStatus status;
DBusConnection *connection;
dbus_uint32_t client_serial;
DBusTimeout *timeout;
int timeout_milliseconds, elapsed_milliseconds;
_dbus_assert (pending != NULL);
if (dbus_pending_call_get_completed (pending))
return;
dbus_pending_call_ref (pending); /* necessary because the call could be canceled */
connection = _dbus_pending_call_get_connection_and_lock (pending);
/* Flush message queue - note, can affect dispatch status */
_dbus_connection_flush_unlocked (connection);
client_serial = _dbus_pending_call_get_reply_serial_unlocked (pending);
/* note that timeout_milliseconds is limited to a smallish value
* in _dbus_pending_call_new() so overflows aren't possible
* below
*/
timeout = _dbus_pending_call_get_timeout_unlocked (pending);
_dbus_get_monotonic_time (&start_tv_sec, &start_tv_usec);
if (timeout)
{
timeout_milliseconds = dbus_timeout_get_interval (timeout);
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): will block %d milliseconds for reply serial %u from %ld sec %ld usec\n",
timeout_milliseconds,
client_serial,
start_tv_sec, start_tv_usec);
}
else
{
timeout_milliseconds = -1;
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): will block for reply serial %u\n", client_serial);
}
/* check to see if we already got the data off the socket */
/* from another blocked pending call */
if (check_for_reply_and_update_dispatch_unlocked (connection, pending))
return;
/* Now we wait... */
/* always block at least once as we know we don't have the reply yet */
_dbus_connection_do_iteration_unlocked (connection,
pending,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_BLOCK,
timeout_milliseconds);
recheck_status:
_dbus_verbose ("top of recheck\n");
HAVE_LOCK_CHECK (connection);
/* queue messages and get status */
status = _dbus_connection_get_dispatch_status_unlocked (connection);
/* the get_completed() is in case a dispatch() while we were blocking
* got the reply instead of us.
*/
if (_dbus_pending_call_get_completed_unlocked (pending))
{
_dbus_verbose ("Pending call completed by dispatch\n");
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
dbus_pending_call_unref (pending);
return;
}
if (status == DBUS_DISPATCH_DATA_REMAINS)
{
if (check_for_reply_and_update_dispatch_unlocked (connection, pending))
return;
}
_dbus_get_monotonic_time (&tv_sec, &tv_usec);
elapsed_milliseconds = (tv_sec - start_tv_sec) * 1000 +
(tv_usec - start_tv_usec) / 1000;
if (!_dbus_connection_get_is_connected_unlocked (connection))
{
DBusMessage *error_msg;
error_msg = generate_local_error_message (client_serial,
DBUS_ERROR_DISCONNECTED,
"Connection was disconnected before a reply was received");
/* on OOM error_msg is set to NULL */
complete_pending_call_and_unlock (connection, pending, error_msg);
dbus_pending_call_unref (pending);
return;
}
else if (connection->disconnect_message_link == NULL)
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): disconnected\n");
else if (timeout == NULL)
{
if (status == DBUS_DISPATCH_NEED_MEMORY)
{
/* Try sleeping a bit, as we aren't sure we need to block for reading,
* we may already have a reply in the buffer and just can't process
* it.
*/
_dbus_verbose ("dbus_connection_send_with_reply_and_block() waiting for more memory\n");
_dbus_memory_pause_based_on_timeout (timeout_milliseconds - elapsed_milliseconds);
}
else
{
/* block again, we don't have the reply buffered yet. */
_dbus_connection_do_iteration_unlocked (connection,
pending,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_BLOCK,
timeout_milliseconds - elapsed_milliseconds);
}
goto recheck_status;
}
else if (tv_sec < start_tv_sec)
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): clock set backward\n");
else if (elapsed_milliseconds < timeout_milliseconds)
{
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): %d milliseconds remain\n", timeout_milliseconds - elapsed_milliseconds);
if (status == DBUS_DISPATCH_NEED_MEMORY)
{
/* Try sleeping a bit, as we aren't sure we need to block for reading,
* we may already have a reply in the buffer and just can't process
* it.
*/
_dbus_verbose ("dbus_connection_send_with_reply_and_block() waiting for more memory\n");
_dbus_memory_pause_based_on_timeout (timeout_milliseconds - elapsed_milliseconds);
}
else
{
/* block again, we don't have the reply buffered yet. */
_dbus_connection_do_iteration_unlocked (connection,
NULL,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_BLOCK,
timeout_milliseconds - elapsed_milliseconds);
}
goto recheck_status;
}
_dbus_verbose ("dbus_connection_send_with_reply_and_block(): Waited %d milliseconds and got no reply\n",
elapsed_milliseconds);
_dbus_assert (!_dbus_pending_call_get_completed_unlocked (pending));
/* unlock and call user code */
complete_pending_call_and_unlock (connection, pending, NULL);
/* update user code on dispatch status */
CONNECTION_LOCK (connection);
status = _dbus_connection_get_dispatch_status_unlocked (connection);
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
dbus_pending_call_unref (pending);
}
/** @} */
/**
* @addtogroup DBusConnection
*
* @{
*/
/**
* Gets a connection to a remote address. If a connection to the given
* address already exists, returns the existing connection with its
* reference count incremented. Otherwise, returns a new connection
* and saves the new connection for possible re-use if a future call
* to dbus_connection_open() asks to connect to the same server.
*
* Use dbus_connection_open_private() to get a dedicated connection
* not shared with other callers of dbus_connection_open().
*
* If the open fails, the function returns #NULL, and provides a
* reason for the failure in the error parameter. Pass #NULL for the
* error parameter if you aren't interested in the reason for
* failure.
*
* Because this connection is shared, no user of the connection
* may call dbus_connection_close(). However, when you are done with the
* connection you should call dbus_connection_unref().
*
* @note Prefer dbus_connection_open() to dbus_connection_open_private()
* unless you have good reason; connections are expensive enough
* that it's wasteful to create lots of connections to the same
* server.
*
* @param address the address.
* @param error address where an error can be returned.
* @returns new connection, or #NULL on failure.
*/
DBusConnection*
dbus_connection_open (const char *address,
DBusError *error)
{
DBusConnection *connection;
_dbus_return_val_if_fail (address != NULL, NULL);
_dbus_return_val_if_error_is_set (error, NULL);
connection = _dbus_connection_open_internal (address,
TRUE,
error);
return connection;
}
/**
* Opens a new, dedicated connection to a remote address. Unlike
* dbus_connection_open(), always creates a new connection.
* This connection will not be saved or recycled by libdbus.
*
* If the open fails, the function returns #NULL, and provides a
* reason for the failure in the error parameter. Pass #NULL for the
* error parameter if you aren't interested in the reason for
* failure.
*
* When you are done with this connection, you must
* dbus_connection_close() to disconnect it,
* and dbus_connection_unref() to free the connection object.
*
* (The dbus_connection_close() can be skipped if the
* connection is already known to be disconnected, for example
* if you are inside a handler for the Disconnected signal.)
*
* @note Prefer dbus_connection_open() to dbus_connection_open_private()
* unless you have good reason; connections are expensive enough
* that it's wasteful to create lots of connections to the same
* server.
*
* @param address the address.
* @param error address where an error can be returned.
* @returns new connection, or #NULL on failure.
*/
DBusConnection*
dbus_connection_open_private (const char *address,
DBusError *error)
{
DBusConnection *connection;
_dbus_return_val_if_fail (address != NULL, NULL);
_dbus_return_val_if_error_is_set (error, NULL);
connection = _dbus_connection_open_internal (address,
FALSE,
error);
return connection;
}
/**
* Increments the reference count of a DBusConnection.
*
* @param connection the connection.
* @returns the connection.
*/
DBusConnection *
dbus_connection_ref (DBusConnection *connection)
{
dbus_int32_t old_refcount;
_dbus_return_val_if_fail (connection != NULL, NULL);
_dbus_return_val_if_fail (connection->generation == _dbus_current_generation, NULL);
old_refcount = _dbus_atomic_inc (&connection->refcount);
_dbus_connection_trace_ref (connection, old_refcount, old_refcount + 1,
"ref");
return connection;
}
static void
free_outgoing_message (void *element,
void *data)
{
DBusMessage *message = element;
DBusConnection *connection = data;
_dbus_message_remove_counter (message, connection->outgoing_counter);
dbus_message_unref (message);
}
/* This is run without the mutex held, but after the last reference
* to the connection has been dropped we should have no thread-related
* problems
*/
static void
_dbus_connection_last_unref (DBusConnection *connection)
{
DBusList *link;
_dbus_verbose ("Finalizing connection %p\n", connection);
_dbus_assert (_dbus_atomic_get (&connection->refcount) == 0);
/* You have to disconnect the connection before unref:ing it. Otherwise
* you won't get the disconnected message.
*/
_dbus_assert (!_dbus_transport_get_is_connected (connection->transport));
_dbus_assert (connection->server_guid == NULL);
/* ---- We're going to call various application callbacks here, hope it doesn't break anything... */
_dbus_object_tree_free_all_unlocked (connection->objects);
dbus_connection_set_dispatch_status_function (connection, NULL, NULL, NULL);
dbus_connection_set_wakeup_main_function (connection, NULL, NULL, NULL);
dbus_connection_set_unix_user_function (connection, NULL, NULL, NULL);
_dbus_watch_list_free (connection->watches);
connection->watches = NULL;
_dbus_timeout_list_free (connection->timeouts);
connection->timeouts = NULL;
_dbus_data_slot_list_free (&connection->slot_list);
link = _dbus_list_get_first_link (&connection->filter_list);
while (link != NULL)
{
DBusMessageFilter *filter = link->data;
DBusList *next = _dbus_list_get_next_link (&connection->filter_list, link);
filter->function = NULL;
_dbus_message_filter_unref (filter); /* calls app callback */
link->data = NULL;
link = next;
}
_dbus_list_clear (&connection->filter_list);
/* ---- Done with stuff that invokes application callbacks */
_dbus_object_tree_unref (connection->objects);
_dbus_hash_table_unref (connection->pending_replies);
connection->pending_replies = NULL;
_dbus_list_clear (&connection->filter_list);
_dbus_list_foreach (&connection->outgoing_messages,
free_outgoing_message,
connection);
_dbus_list_clear (&connection->outgoing_messages);
_dbus_list_foreach (&connection->incoming_messages,
(DBusForeachFunction) dbus_message_unref,
NULL);
_dbus_list_clear (&connection->incoming_messages);
_dbus_counter_unref (connection->outgoing_counter);
_dbus_transport_unref (connection->transport);
if (connection->disconnect_message_link)
{
DBusMessage *message = connection->disconnect_message_link->data;
dbus_message_unref (message);
_dbus_list_free_link (connection->disconnect_message_link);
}
_dbus_condvar_free_at_location (&connection->dispatch_cond);
_dbus_condvar_free_at_location (&connection->io_path_cond);
_dbus_cmutex_free_at_location (&connection->io_path_mutex);
_dbus_cmutex_free_at_location (&connection->dispatch_mutex);
_dbus_rmutex_free_at_location (&connection->slot_mutex);
_dbus_rmutex_free_at_location (&connection->mutex);
dbus_free (connection);
}
/**
* Decrements the reference count of a DBusConnection, and finalizes
* it if the count reaches zero.
*
* Note: it is a bug to drop the last reference to a connection that
* is still connected.
*
* For shared connections, libdbus will own a reference
* as long as the connection is connected, so you can know that either
* you don't have the last reference, or it's OK to drop the last reference.
* Most connections are shared. dbus_connection_open() and dbus_bus_get()
* return shared connections.
*
* For private connections, the creator of the connection must arrange for
* dbus_connection_close() to be called prior to dropping the last reference.
* Private connections come from dbus_connection_open_private() or dbus_bus_get_private().
*
* @param connection the connection.
*/
void
dbus_connection_unref (DBusConnection *connection)
{
dbus_int32_t old_refcount;
_dbus_return_if_fail (connection != NULL);
_dbus_return_if_fail (connection->generation == _dbus_current_generation);
old_refcount = _dbus_atomic_dec (&connection->refcount);
_dbus_connection_trace_ref (connection, old_refcount, old_refcount - 1,
"unref");
if (old_refcount == 1)
{
#ifndef DBUS_DISABLE_CHECKS
if (_dbus_transport_get_is_connected (connection->transport))
{
_dbus_warn_check_failed ("The last reference on a connection was dropped without closing the connection. This is a bug in an application. See dbus_connection_unref() documentation for details.\n%s",
connection->shareable ?
"Most likely, the application called unref() too many times and removed a reference belonging to libdbus, since this is a shared connection.\n" :
"Most likely, the application was supposed to call dbus_connection_close(), since this is a private connection.\n");
return;
}
#endif
_dbus_connection_last_unref (connection);
}
}
/*
* Note that the transport can disconnect itself (other end drops us)
* and in that case this function never runs. So this function must
* not do anything more than disconnect the transport and update the
* dispatch status.
*
* If the transport self-disconnects, then we assume someone will
* dispatch the connection to cause the dispatch status update.
*/
static void
_dbus_connection_close_possibly_shared_and_unlock (DBusConnection *connection)
{
DBusDispatchStatus status;
HAVE_LOCK_CHECK (connection);
_dbus_verbose ("Disconnecting %p\n", connection);
/* We need to ref because update_dispatch_status_and_unlock will unref
* the connection if it was shared and libdbus was the only remaining
* refcount holder.
*/
_dbus_connection_ref_unlocked (connection);
_dbus_transport_disconnect (connection->transport);
/* This has the side effect of queuing the disconnect message link
* (unless we don't have enough memory, possibly, so don't assert it).
* After the disconnect message link is queued, dbus_bus_get/dbus_connection_open
* should never again return the newly-disconnected connection.
*
* However, we only unref the shared connection and exit_on_disconnect when
* the disconnect message reaches the head of the message queue,
* NOT when it's first queued.
*/
status = _dbus_connection_get_dispatch_status_unlocked (connection);
/* This calls out to user code */
_dbus_connection_update_dispatch_status_and_unlock (connection, status);
/* Could also call out to user code */
dbus_connection_unref (connection);
}
/**
* Closes a private connection, so no further data can be sent or received.
* This disconnects the transport (such as a socket) underlying the
* connection.
*
* Attempts to send messages after closing a connection are safe, but will result in
* error replies generated locally in libdbus.
*
* This function does not affect the connection's reference count. It's
* safe to close a connection more than once; all calls after the
* first do nothing. It's impossible to "reopen" a connection, a
* new connection must be created. This function may result in a call
* to the DBusDispatchStatusFunction set with
* dbus_connection_set_dispatch_status_function(), as the disconnect
* message it generates needs to be dispatched.
*
* If a connection is dropped by the remote application, it will
* close itself.
*
* You must close a connection prior to releasing the last reference to
* the connection. If you dbus_connection_unref() for the last time
* without closing the connection, the results are undefined; it
* is a bug in your program and libdbus will try to print a warning.
*
* You may not close a shared connection. Connections created with
* dbus_connection_open() or dbus_bus_get() are shared.
* These connections are owned by libdbus, and applications should
* only unref them, never close them. Applications can know it is
* safe to unref these connections because libdbus will be holding a
* reference as long as the connection is open. Thus, either the
* connection is closed and it is OK to drop the last reference,
* or the connection is open and the app knows it does not have the
* last reference.
*
* Connections created with dbus_connection_open_private() or
* dbus_bus_get_private() are not kept track of or referenced by
* libdbus. The creator of these connections is responsible for
* calling dbus_connection_close() prior to releasing the last
* reference, if the connection is not already disconnected.
*
* @param connection the private (unshared) connection to close
*/
void
dbus_connection_close (DBusConnection *connection)
{
_dbus_return_if_fail (connection != NULL);
_dbus_return_if_fail (connection->generation == _dbus_current_generation);
CONNECTION_LOCK (connection);
#ifndef DBUS_DISABLE_CHECKS
if (connection->shareable)
{
CONNECTION_UNLOCK (connection);
_dbus_warn_check_failed ("Applications must not close shared connections - see dbus_connection_close() docs. This is a bug in the application.\n");
return;
}
#endif
_dbus_connection_close_possibly_shared_and_unlock (connection);
}
static dbus_bool_t
_dbus_connection_get_is_connected_unlocked (DBusConnection *connection)
{
HAVE_LOCK_CHECK (connection);
return _dbus_transport_get_is_connected (connection->transport);
}
/**
* Gets whether the connection is currently open. A connection may
* become disconnected when the remote application closes its end, or
* exits; a connection may also be disconnected with
* dbus_connection_close().
*
* There are not separate states for "closed" and "disconnected," the two
* terms are synonymous. This function should really be called
* get_is_open() but for historical reasons is not.
*
* @param connection the connection.
* @returns #TRUE if the connection is still alive.
*/
dbus_bool_t
dbus_connection_get_is_connected (DBusConnection *connection)
{
dbus_bool_t res;
_dbus_return_val_if_fail (connection != NULL, FALSE);
CONNECTION_LOCK (connection);
res = _dbus_connection_get_is_connected_unlocked (connection);
CONNECTION_UNLOCK (connection);
return res;
}
/**
* Gets whether the connection was authenticated. (Note that
* if the connection was authenticated then disconnected,
* this function still returns #TRUE)
*
* @param connection the connection
* @returns #TRUE if the connection was ever authenticated
*/
dbus_bool_t
dbus_connection_get_is_authenticated (DBusConnection *connection)
{
dbus_bool_t res;
_dbus_return_val_if_fail (connection != NULL, FALSE);
CONNECTION_LOCK (connection);
res = _dbus_transport_get_is_authenticated (connection->transport);
CONNECTION_UNLOCK (connection);
return res;
}
/**
* Gets whether the connection is not authenticated as a specific
* user. If the connection is not authenticated, this function
* returns #TRUE, and if it is authenticated but as an anonymous user,
* it returns #TRUE. If it is authenticated as a specific user, then
* this returns #FALSE. (Note that if the connection was authenticated
* as anonymous then disconnected, this function still returns #TRUE.)
*
* If the connection is not anonymous, you can use
* dbus_connection_get_unix_user() and
* dbus_connection_get_windows_user() to see who it's authorized as.
*
* If you want to prevent non-anonymous authorization, use
* dbus_server_set_auth_mechanisms() to remove the mechanisms that
* allow proving user identity (i.e. only allow the ANONYMOUS
* mechanism).
*
* @param connection the connection
* @returns #TRUE if not authenticated or authenticated as anonymous
*/
dbus_bool_t
dbus_connection_get_is_anonymous (DBusConnection *connection)
{
dbus_bool_t res;
_dbus_return_val_if_fail (connection != NULL, FALSE);
CONNECTION_LOCK (connection);
res = _dbus_transport_get_is_anonymous (connection->transport);
CONNECTION_UNLOCK (connection);
return res;
}
/**
* Gets the ID of the server address we are authenticated to, if this
* connection is on the client side. If the connection is on the
* server side, this will always return #NULL - use dbus_server_get_id()
* to get the ID of your own server, if you are the server side.
*
* If a client-side connection is not authenticated yet, the ID may be
* available if it was included in the server address, but may not be
* available. The only way to be sure the server ID is available
* is to wait for authentication to complete.
*
* In general, each mode of connecting to a given server will have
* its own ID. So for example, if the session bus daemon is listening
* on UNIX domain sockets and on TCP, then each of those modalities
* will have its own server ID.
*
* If you want an ID that identifies an entire session bus, look at
* dbus_bus_get_id() instead (which is just a convenience wrapper
* around the org.freedesktop.DBus.GetId method invoked on the bus).
*
* You can also get a machine ID; see dbus_get_local_machine_id() to
* get the machine you are on. There isn't a convenience wrapper, but
* you can invoke org.freedesktop.DBus.Peer.GetMachineId on any peer
* to get the machine ID on the other end.
*
* The D-Bus specification describes the server ID and other IDs in a
* bit more detail.
*
* @param connection the connection
* @returns the server ID or #NULL if no memory or the connection is server-side
*/
char*
dbus_connection_get_server_id (DBusConnection *connection)
{
char *id;
_dbus_return_val_if_fail (connection != NULL, NULL);
CONNECTION_LOCK (connection);
id = _dbus_strdup (_dbus_transport_get_server_id (connection->transport));
CONNECTION_UNLOCK (connection);
return id;
}
/**
* Tests whether a certain type can be send via the connection. This
* will always return TRUE for all types, with the exception of
* DBUS_TYPE_UNIX_FD. The function will return TRUE for
* DBUS_TYPE_UNIX_FD only on systems that know Unix file descriptors
* and can send them via the chosen transport and when the remote side
* supports this.
*
* This function can be used to do runtime checking for types that
* might be unknown to the specific D-Bus client implementation
* version, i.e. it will return FALSE for all types this
* implementation does not know, including invalid or reserved types.
*
* @param connection the connection
* @param type the type to check
* @returns TRUE if the type may be send via the connection
*/
dbus_bool_t
dbus_connection_can_send_type(DBusConnection *connection,
int type)
{
_dbus_return_val_if_fail (connection != NULL, FALSE);
if (!dbus_type_is_valid (type))
return FALSE;
if (type != DBUS_TYPE_UNIX_FD)
return TRUE;
#ifdef HAVE_UNIX_FD_PASSING
{
dbus_bool_t b;
CONNECTION_LOCK(connection);
b = _dbus_transport_can_pass_unix_fd(connection->transport);
CONNECTION_UNLOCK(connection);
return b;
}
#endif
return FALSE;
}
/**
* Set whether _exit() should be called when the connection receives a
* disconnect signal. The call to _exit() comes after any handlers for
* the disconnect signal run; handlers can cancel the exit by calling
* this function.
*
* By default, exit_on_disconnect is #FALSE; but for message bus
* connections returned from dbus_bus_get() it will be toggled on
* by default.
*
* @param connection the connection
* @param exit_on_disconnect #TRUE if _exit() should be called after a disconnect signal
*/
void
dbus_connection_set_exit_on_disconnect (DBusConnection *connection,
dbus_bool_t exit_on_disconnect)
{
_dbus_return_if_fail (connection != NULL);
CONNECTION_LOCK (connection);
connection->exit_on_disconnect = exit_on_disconnect != FALSE;
CONNECTION_UNLOCK (connection);
}
/**
* Preallocates resources needed to send a message, allowing the message
* to be sent without the possibility of memory allocation failure.
* Allows apps to create a future guarantee that they can send
* a message regardless of memory shortages.