D-Bus  1.16.2
dbus-pending-call.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-pending-call.c Object representing a call in progress.
3  *
4  * Copyright (C) 2002, 2003 Red Hat Inc.
5  *
6  * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
7  *
8  * Licensed under the Academic Free License version 2.1
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  *
24  */
25 
26 #include <config.h>
27 #include "dbus-internals.h"
28 #include "dbus-connection-internal.h"
29 #include "dbus-message-internal.h"
30 #include "dbus-pending-call-internal.h"
31 #include "dbus-pending-call.h"
32 #include "dbus-list.h"
33 #include "dbus-threads.h"
34 #include "dbus-test.h"
35 
55 #define CONNECTION_LOCK(connection) _dbus_connection_lock(connection)
56 
59 #define CONNECTION_UNLOCK(connection) _dbus_connection_unlock(connection)
60 
65 {
85  unsigned int completed : 1;
89  unsigned int timeout_added : 1;
90 };
91 
92 static void
93 _dbus_pending_call_trace_ref (DBusPendingCall *pending_call,
94  int old_refcount,
95  int new_refcount,
96  const char *why)
97 {
98 #ifdef DBUS_ENABLE_VERBOSE_MODE
99  static int enabled = -1;
100 
101  _dbus_trace_ref ("DBusPendingCall", pending_call, old_refcount,
102  new_refcount, why, "DBUS_PENDING_CALL_TRACE", &enabled);
103 #endif
104 }
105 
106 /* protected by _DBUS_LOCK_pending_call_slots */
107 static dbus_int32_t notify_user_data_slot = -1;
108 
121  int timeout_milliseconds,
122  DBusTimeoutHandler timeout_handler)
123 {
124  DBusPendingCall *pending;
125  DBusTimeout *timeout;
126 
127  _dbus_assert (timeout_milliseconds >= 0 || timeout_milliseconds == -1);
128 
129  if (timeout_milliseconds == -1)
130  timeout_milliseconds = _DBUS_DEFAULT_TIMEOUT_VALUE;
131 
132  if (!dbus_pending_call_allocate_data_slot (&notify_user_data_slot))
133  return NULL;
134 
135  pending = dbus_new0 (DBusPendingCall, 1);
136 
137  if (pending == NULL)
138  {
139  dbus_pending_call_free_data_slot (&notify_user_data_slot);
140  return NULL;
141  }
142 
143  if (timeout_milliseconds != DBUS_TIMEOUT_INFINITE)
144  {
145  timeout = _dbus_timeout_new (timeout_milliseconds,
146  timeout_handler,
147  pending, NULL);
148 
149  if (timeout == NULL)
150  {
151  dbus_pending_call_free_data_slot (&notify_user_data_slot);
152  dbus_free (pending);
153  return NULL;
154  }
155 
156  pending->timeout = timeout;
157  }
158  else
159  {
160  pending->timeout = NULL;
161  }
162 
163  _dbus_atomic_inc (&pending->refcount);
164  pending->connection = connection;
166 
168 
169  _dbus_pending_call_trace_ref (pending, 0, 1, "new_unlocked");
170 
171  return pending;
172 }
173 
182 void
184  DBusMessage *message)
185 {
186  if (message == NULL)
187  {
188  message = pending->timeout_link->data;
189  _dbus_list_clear (&pending->timeout_link);
190  }
191  else
192  dbus_message_ref (message);
193 
194  _dbus_verbose (" handing message %p (%s) to pending call serial %u\n",
195  message,
197  "method return" :
199  "error" : "other type",
200  pending->reply_serial);
201 
202  _dbus_assert (pending->reply == NULL);
204  pending->reply = message;
205 }
206 
217 void
219 {
220  _dbus_assert (!pending->completed);
221 
222  pending->completed = TRUE;
223 }
224 
234 void
236 {
237  _dbus_assert (pending->completed);
238 
239  if (pending->function)
240  {
241  void *user_data;
242  user_data = dbus_pending_call_get_data (pending,
243  notify_user_data_slot);
244 
245  (* pending->function) (pending, user_data);
246  }
247 }
248 
256 void
258  DBusConnection *connection)
259 {
260  _dbus_assert (connection == pending->connection);
261 
262  if (pending->timeout_link)
263  {
265  pending->timeout_link);
266  pending->timeout_link = NULL;
267  }
268 }
269 
278 {
279  _dbus_assert (pending != NULL);
280 
281  return pending->timeout_added;
282 }
283 
284 
291 void
293  dbus_bool_t is_added)
294 {
295  _dbus_assert (pending != NULL);
296 
297  pending->timeout_added = is_added;
298 }
299 
300 
307 DBusTimeout *
309 {
310  _dbus_assert (pending != NULL);
311 
312  return pending->timeout;
313 }
314 
323 {
324  _dbus_assert (pending != NULL);
325 
326  return pending->reply_serial;
327 }
328 
335 void
337  dbus_uint32_t serial)
338 {
339  _dbus_assert (pending != NULL);
340  _dbus_assert (pending->reply_serial == 0);
341 
342  pending->reply_serial = serial;
343 }
344 
353 {
354  _dbus_assert (pending != NULL);
355 
356  CONNECTION_LOCK (pending->connection);
357  return pending->connection;
358 }
359 
368 {
369  _dbus_assert (pending != NULL);
370 
371  return pending->connection;
372 }
373 
384  DBusMessage *message,
385  dbus_uint32_t serial)
386 {
387  DBusList *reply_link;
388  DBusMessage *reply;
389 
391  "Did not receive a reply. Possible causes include: "
392  "the remote application did not send a reply, "
393  "the message bus security policy blocked the reply, "
394  "the reply timeout expired, or "
395  "the network connection was broken.");
396  if (reply == NULL)
397  return FALSE;
398 
399  reply_link = _dbus_list_alloc_link (reply);
400  if (reply_link == NULL)
401  {
402  /* it's OK to unref this, nothing that could have attached a callback
403  * has ever seen it */
404  dbus_message_unref (reply);
405  return FALSE;
406  }
407 
408  pending->timeout_link = reply_link;
409 
411 
412  return TRUE;
413 }
414 
424 {
425  dbus_int32_t old_refcount;
426 
427  old_refcount = _dbus_atomic_inc (&pending->refcount);
428  _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount + 1,
429  "ref_unlocked");
430 
431  return pending;
432 }
433 
434 
435 static void
436 _dbus_pending_call_last_unref (DBusPendingCall *pending)
437 {
438  DBusConnection *connection;
439 
440  /* If we get here, we should be already detached
441  * from the connection, or never attached.
442  */
443  _dbus_assert (!pending->timeout_added);
444 
445  connection = pending->connection;
446 
447  /* this assumes we aren't holding connection lock... */
449 
450  if (pending->timeout != NULL)
451  _dbus_timeout_unref (pending->timeout);
452 
453  if (pending->timeout_link)
454  {
457  pending->timeout_link = NULL;
458  }
459 
460  if (pending->reply)
461  {
462  dbus_message_unref (pending->reply);
463  pending->reply = NULL;
464  }
465 
466  dbus_free (pending);
467 
468  dbus_pending_call_free_data_slot (&notify_user_data_slot);
469 
470  /* connection lock should not be held. */
471  /* Free the connection last to avoid a weird state while
472  * calling out to application code where the pending exists
473  * but not the connection.
474  */
475  dbus_connection_unref (connection);
476 }
477 
485 void
487 {
488  dbus_int32_t old_refcount;
489 
490  old_refcount = _dbus_atomic_dec (&pending->refcount);
491  _dbus_assert (old_refcount > 0);
492  _dbus_pending_call_trace_ref (pending, old_refcount,
493  old_refcount - 1, "unref_and_unlock");
494 
495  CONNECTION_UNLOCK (pending->connection);
496 
497  if (old_refcount == 1)
498  _dbus_pending_call_last_unref (pending);
499 }
500 
510 {
511  return pending->completed;
512 }
513 
514 static DBusDataSlotAllocator slot_allocator =
515  _DBUS_DATA_SLOT_ALLOCATOR_INIT (_DBUS_LOCK_NAME (pending_call_slots));
516 
532  dbus_int32_t slot,
533  void *data,
534  DBusFreeFunction free_data_func)
535 {
536  DBusFreeFunction old_free_func;
537  void *old_data;
538  dbus_bool_t retval;
539 
540  retval = _dbus_data_slot_list_set (&slot_allocator,
541  &pending->slot_list,
542  slot, data, free_data_func,
543  &old_free_func, &old_data);
544 
545  /* Drop locks to call out to app code */
546  CONNECTION_UNLOCK (pending->connection);
547 
548  if (retval)
549  {
550  if (old_free_func)
551  (* old_free_func) (old_data);
552  }
553 
554  CONNECTION_LOCK (pending->connection);
555 
556  return retval;
557 }
558 
607 {
608  dbus_int32_t old_refcount;
609 
610  _dbus_return_val_if_fail (pending != NULL, NULL);
611 
612  old_refcount = _dbus_atomic_inc (&pending->refcount);
613  _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount + 1,
614  "ref");
615 
616  return pending;
617 }
618 
625 void
627 {
628  dbus_int32_t old_refcount;
629 
630  _dbus_return_if_fail (pending != NULL);
631 
632  old_refcount = _dbus_atomic_dec (&pending->refcount);
633  _dbus_pending_call_trace_ref (pending, old_refcount, old_refcount - 1,
634  "unref");
635 
636  if (old_refcount == 1)
637  _dbus_pending_call_last_unref(pending);
638 }
639 
653  void *user_data,
654  DBusFreeFunction free_user_data)
655 {
656  dbus_bool_t ret = FALSE;
657 
658  _dbus_return_val_if_fail (pending != NULL, FALSE);
659 
660  CONNECTION_LOCK (pending->connection);
661 
662  /* could invoke application code! */
663  if (!_dbus_pending_call_set_data_unlocked (pending, notify_user_data_slot,
664  user_data, free_user_data))
665  goto out;
666 
667  pending->function = function;
668  ret = TRUE;
669 
670 out:
671  CONNECTION_UNLOCK (pending->connection);
672 
673  return ret;
674 }
675 
691 void
693 {
694  _dbus_return_if_fail (pending != NULL);
695 
697  pending);
698 }
699 
709 {
710  dbus_bool_t completed;
711 
712  _dbus_return_val_if_fail (pending != NULL, FALSE);
713 
714  CONNECTION_LOCK (pending->connection);
715  completed = pending->completed;
716  CONNECTION_UNLOCK (pending->connection);
717 
718  return completed;
719 }
720 
732 {
733  DBusMessage *message;
734 
735  _dbus_return_val_if_fail (pending != NULL, NULL);
736  _dbus_return_val_if_fail (pending->completed, NULL);
737  _dbus_return_val_if_fail (pending->reply != NULL, NULL);
738 
739  CONNECTION_LOCK (pending->connection);
740 
741  message = pending->reply;
742  pending->reply = NULL;
743 
744  CONNECTION_UNLOCK (pending->connection);
745 
746  _dbus_message_trace_ref (message, -1, -1, "dbus_pending_call_steal_reply");
747  return message;
748 }
749 
765 void
767 {
768  _dbus_return_if_fail (pending != NULL);
769 
771 }
772 
789 {
790  _dbus_return_val_if_fail (slot_p != NULL, FALSE);
791 
792  return _dbus_data_slot_allocator_alloc (&slot_allocator,
793  slot_p);
794 }
795 
807 void
809 {
810  _dbus_return_if_fail (slot_p != NULL);
811  _dbus_return_if_fail (*slot_p >= 0);
812 
813  _dbus_data_slot_allocator_free (&slot_allocator, slot_p);
814 }
815 
831  dbus_int32_t slot,
832  void *data,
833  DBusFreeFunction free_data_func)
834 {
835  dbus_bool_t retval;
836 
837  _dbus_return_val_if_fail (pending != NULL, FALSE);
838  _dbus_return_val_if_fail (slot >= 0, FALSE);
839 
840 
841  CONNECTION_LOCK (pending->connection);
842  retval = _dbus_pending_call_set_data_unlocked (pending, slot, data, free_data_func);
843  CONNECTION_UNLOCK (pending->connection);
844  return retval;
845 }
846 
855 void*
857  dbus_int32_t slot)
858 {
859  void *res;
860 
861  _dbus_return_val_if_fail (pending != NULL, NULL);
862 
863  CONNECTION_LOCK (pending->connection);
864  res = _dbus_data_slot_list_get (&slot_allocator,
865  &pending->slot_list,
866  slot);
867  CONNECTION_UNLOCK (pending->connection);
868 
869  return res;
870 }
871 
unsigned int dbus_uint32_t
A 32-bit unsigned integer on all platforms.
An atomic integer safe to increment or decrement from multiple threads.
Definition: dbus-sysdeps.h:339
DBusMessage * dbus_message_ref(DBusMessage *message)
Increments the reference count of a DBusMessage.
DBusTimeout * _dbus_timeout_new(int interval, DBusTimeoutHandler handler, void *data, DBusFreeFunction free_data_function)
Creates a new DBusTimeout, enabled by default.
Definition: dbus-timeout.c:66
Internals of DBusTimeout.
Definition: dbus-timeout.c:42
#define NULL
A null pointer, defined appropriately for C or C++.
void(* DBusFreeFunction)(void *memory)
The type of a function which frees a block of memory.
Definition: dbus-memory.h:65
void _dbus_connection_queue_synthesized_message_link(DBusConnection *connection, DBusList *link)
Adds a link + message to the incoming message queue.
DBusConnection * _dbus_pending_call_get_connection_unlocked(DBusPendingCall *pending)
Gets the connection associated with this pending call.
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:710
void _dbus_pending_call_finish_completion(DBusPendingCall *pending)
Call the notifier function for the pending call.
void(* DBusPendingCallNotifyFunction)(DBusPendingCall *pending, void *user_data)
Called when a pending call now has a reply available.
DBusMessage * dbus_pending_call_steal_reply(DBusPendingCall *pending)
Gets the reply, or returns NULL if none has been received yet.
dbus_bool_t _dbus_pending_call_set_data_unlocked(DBusPendingCall *pending, dbus_int32_t slot, void *data, DBusFreeFunction free_data_func)
Stores a pointer on a DBusPendingCall, along with an optional function to be used for freeing the dat...
DBusDataSlotList slot_list
Data stored by allocated integer ID.
void * data
Data stored at this element.
Definition: dbus-list.h:40
Implementation details of DBusPendingCall - all fields are private.
Implementation details of DBusConnection.
#define DBUS_MESSAGE_TYPE_ERROR
Message type of an error reply message, see dbus_message_get_type()
DBusList * _dbus_list_alloc_link(void *data)
Allocates a linked list node.
Definition: dbus-list.c:245
#define DBUS_MESSAGE_TYPE_METHOD_RETURN
Message type of a method return message, see dbus_message_get_type()
dbus_bool_t dbus_pending_call_set_notify(DBusPendingCall *pending, DBusPendingCallNotifyFunction function, void *user_data, DBusFreeFunction free_user_data)
Sets a notification function to be called when the reply is received or the pending call times out...
dbus_bool_t dbus_pending_call_set_data(DBusPendingCall *pending, dbus_int32_t slot, void *data, DBusFreeFunction free_data_func)
Stores a pointer on a DBusPendingCall, along with an optional function to be used for freeing the dat...
dbus_bool_t _dbus_pending_call_get_completed_unlocked(DBusPendingCall *pending)
Checks whether the pending call has received a reply yet, or not.
void _dbus_connection_block_pending_call(DBusPendingCall *pending)
Blocks until a pending call times out or gets a reply.
void * dbus_pending_call_get_data(DBusPendingCall *pending, dbus_int32_t slot)
Retrieves data previously set with dbus_pending_call_set_data().
void dbus_pending_call_free_data_slot(dbus_int32_t *slot_p)
Deallocates a global ID for DBusPendingCall data slots.
Internals of DBusMessage.
unsigned int timeout_added
TRUE if we have added the timeout.
DBusConnection * connection
Connections we're associated with.
dbus_bool_t _dbus_pending_call_set_timeout_error_unlocked(DBusPendingCall *pending, DBusMessage *message, dbus_uint32_t serial)
Sets the reply message associated with the pending call to a timeout error.
dbus_bool_t dbus_pending_call_get_completed(DBusPendingCall *pending)
Checks whether the pending call has received a reply yet, or not.
#define dbus_new0(type, count)
Safe macro for using dbus_malloc0().
Definition: dbus-memory.h:60
#define _DBUS_LOCK_NAME(name)
Expands to name of a global lock variable.
DBusList * timeout_link
Preallocated timeout response.
dbus_bool_t _dbus_pending_call_is_timeout_added_unlocked(DBusPendingCall *pending)
Checks to see if a timeout has been added.
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:37
DBusTimeout * timeout
Timeout.
void dbus_pending_call_cancel(DBusPendingCall *pending)
Cancels the pending call, such that any reply or error received will just be ignored.
dbus_int32_t _dbus_atomic_inc(DBusAtomic *atomic)
Atomically increments an integer.
dbus_bool_t _dbus_data_slot_list_set(DBusDataSlotAllocator *allocator, DBusDataSlotList *list, int slot, void *data, DBusFreeFunction free_data_func, DBusFreeFunction *old_free_func, void **old_data)
Stores a pointer in the data slot list, along with an optional function to be used for freeing the da...
void _dbus_timeout_unref(DBusTimeout *timeout)
Decrements the reference count of a DBusTimeout object and finalizes the object if the count reaches ...
Definition: dbus-timeout.c:111
#define DBUS_ERROR_NO_REPLY
No reply to a message expecting one, usually means a timeout occurred.
dbus_bool_t dbus_pending_call_allocate_data_slot(dbus_int32_t *slot_p)
Allocates an integer ID to be used for storing application-specific data on any DBusPendingCall.
DBusPendingCallNotifyFunction function
Notifier when reply arrives.
dbus_uint32_t dbus_message_get_reply_serial(DBusMessage *message)
Returns the serial that the message is a reply to or 0 if none.
DBusPendingCall * dbus_pending_call_ref(DBusPendingCall *pending)
Increments the reference count on a pending call.
dbus_uint32_t _dbus_pending_call_get_reply_serial_unlocked(DBusPendingCall *pending)
Gets the reply's serial number.
void * _dbus_data_slot_list_get(DBusDataSlotAllocator *allocator, DBusDataSlotList *list, int slot)
Retrieves data previously set with _dbus_data_slot_list_set_data().
#define CONNECTION_UNLOCK(connection)
shorter and more visible way to write _dbus_connection_unlock()
#define TRUE
Expands to "1".
void _dbus_data_slot_list_init(DBusDataSlotList *list)
Initializes a slot list.
Data structure that stores the actual user data set at a given slot.
Definition: dbus-dataslot.h:71
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
void _dbus_list_free_link(DBusList *link)
Frees a linked list node allocated with _dbus_list_alloc_link.
Definition: dbus-list.c:257
void dbus_pending_call_unref(DBusPendingCall *pending)
Decrements the reference count on a pending call, freeing it if the count reaches 0...
An allocator that tracks a set of slot IDs.
Definition: dbus-dataslot.h:57
#define DBUS_TIMEOUT_INFINITE
An integer constant representing an infinite timeout.
void _dbus_pending_call_queue_timeout_error_unlocked(DBusPendingCall *pending, DBusConnection *connection)
If the pending call hasn't been timed out, add its timeout error reply to the connection's incoming m...
void dbus_pending_call_block(DBusPendingCall *pending)
Block until the pending call is completed.
DBusPendingCall * _dbus_pending_call_new_unlocked(DBusConnection *connection, int timeout_milliseconds, DBusTimeoutHandler timeout_handler)
Creates a new pending reply object.
dbus_int32_t _dbus_atomic_dec(DBusAtomic *atomic)
Atomically decrement an integer.
void _dbus_pending_call_set_reply_unlocked(DBusPendingCall *pending, DBusMessage *message)
Sets the reply of a pending call with the given message, or if the message is NULL, by timing out the pending call.
A node in a linked list.
Definition: dbus-list.h:36
#define CONNECTION_LOCK(connection)
Internals of DBusPendingCall.
unsigned int completed
TRUE if some thread has taken responsibility for completing this pending call: either the pending cal...
void _dbus_connection_remove_pending_call(DBusConnection *connection, DBusPendingCall *pending)
Removes a pending call from the connection, such that the pending reply will be ignored.
dbus_uint32_t reply_serial
Expected serial of reply.
#define FALSE
Expands to "0".
int dbus_message_get_type(DBusMessage *message)
Gets the type of a message.
void dbus_connection_unref(DBusConnection *connection)
Decrements the reference count of a DBusConnection, and finalizes it if the count reaches zero...
dbus_bool_t _dbus_data_slot_allocator_alloc(DBusDataSlotAllocator *allocator, dbus_int32_t *slot_id_p)
Allocates an integer ID to be used for storing data in a DBusDataSlotList.
Definition: dbus-dataslot.c:72
DBusPendingCall * _dbus_pending_call_ref_unlocked(DBusPendingCall *pending)
Increments the reference count on a pending call, while the lock on its connection is already held...
DBUS_PRIVATE_EXPORT DBusConnection * _dbus_connection_ref_unlocked(DBusConnection *connection)
Increments the reference count of a DBusConnection.
int dbus_int32_t
A 32-bit signed integer on all platforms.
DBusTimeout * _dbus_pending_call_get_timeout_unlocked(DBusPendingCall *pending)
Retrives the timeout.
void _dbus_data_slot_allocator_free(DBusDataSlotAllocator *allocator, dbus_int32_t *slot_id_p)
Deallocates an ID previously allocated with _dbus_data_slot_allocator_alloc().
DBusAtomic refcount
reference count
void dbus_message_unref(DBusMessage *message)
Decrements the reference count of a DBusMessage, freeing the message if the count reaches 0...
void _dbus_pending_call_set_reply_serial_unlocked(DBusPendingCall *pending, dbus_uint32_t serial)
Sets the reply's serial number.
void _dbus_pending_call_unref_and_unlock(DBusPendingCall *pending)
Decrements the reference count on a pending call, freeing it if the count reaches 0...
void _dbus_pending_call_start_completion_unlocked(DBusPendingCall *pending)
Sets the pending call to completed.
void _dbus_pending_call_set_timeout_added_unlocked(DBusPendingCall *pending, dbus_bool_t is_added)
Sets wether the timeout has been added.
DBusConnection * _dbus_pending_call_get_connection_and_lock(DBusPendingCall *pending)
Gets the connection associated with this pending call.
void _dbus_data_slot_list_free(DBusDataSlotList *list)
Frees the data slot list and all data slots contained in it, calling application-provided free functi...
void _dbus_list_clear(DBusList **list)
Frees all links in the list and sets the list head to NULL.
Definition: dbus-list.c:545
dbus_bool_t(* DBusTimeoutHandler)(void *data)
function to run when the timeout is handled
Definition: dbus-timeout.h:43
DBusMessage * reply
Reply (after we've received it)
DBusMessage * dbus_message_new_error(DBusMessage *reply_to, const char *error_name, const char *error_message)
Creates a new message that is an error reply to another message.