D-Bus  1.16.2
dbus-watch.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-watch.c DBusWatch implementation
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-watch.h"
29 #include "dbus-list.h"
30 
42 struct DBusWatch
43 {
44  int refcount;
45  DBusPollable fd;
46  unsigned int flags;
49  void *handler_data;
52  void *data;
54  unsigned int enabled : 1;
55  unsigned int oom_last_time : 1;
56 };
57 
59 _dbus_watch_get_enabled (DBusWatch *watch)
60 {
61  return watch->enabled;
62 }
63 
65 _dbus_watch_get_oom_last_time (DBusWatch *watch)
66 {
67  return watch->oom_last_time;
68 }
69 
70 void
71 _dbus_watch_set_oom_last_time (DBusWatch *watch,
72  dbus_bool_t oom)
73 {
74  watch->oom_last_time = oom;
75 }
76 
89 DBusWatch*
90 _dbus_watch_new (DBusPollable fd,
91  unsigned int flags,
92  dbus_bool_t enabled,
93  DBusWatchHandler handler,
94  void *data,
95  DBusFreeFunction free_data_function)
96 {
97  DBusWatch *watch;
98 
99 #define VALID_WATCH_FLAGS (DBUS_WATCH_WRITABLE | DBUS_WATCH_READABLE)
100 
101  _dbus_assert ((flags & VALID_WATCH_FLAGS) == flags);
102 
103  watch = dbus_new0 (DBusWatch, 1);
104  if (watch == NULL)
105  return NULL;
106 
107  watch->refcount = 1;
108  watch->fd = fd;
109  watch->flags = flags;
110  watch->enabled = enabled;
111 
112  watch->handler = handler;
113  watch->handler_data = data;
114  watch->free_handler_data_function = free_data_function;
115 
116  return watch;
117 }
118 
125 DBusWatch *
127 {
128  watch->refcount += 1;
129 
130  return watch;
131 }
132 
139 void
141 {
142  _dbus_assert (watch != NULL);
143  _dbus_assert (watch->refcount > 0);
144 
145  watch->refcount -= 1;
146  if (watch->refcount == 0)
147  {
148  if (_dbus_pollable_is_valid (watch->fd))
149  _dbus_warn ("this watch should have been invalidated");
150 
151  dbus_watch_set_data (watch, NULL, NULL); /* call free_data_function */
152 
153  if (watch->free_handler_data_function)
154  (* watch->free_handler_data_function) (watch->handler_data);
155 
156  dbus_free (watch);
157  }
158 }
159 
170 void
172 {
173  _dbus_pollable_invalidate (&watch->fd);
174  watch->flags = 0;
175 }
176 
186 void
188  unsigned int *condition)
189 {
190  if (!(watch->flags & DBUS_WATCH_READABLE))
191  *condition &= ~DBUS_WATCH_READABLE;
192  if (!(watch->flags & DBUS_WATCH_WRITABLE))
193  *condition &= ~DBUS_WATCH_WRITABLE;
194 }
195 
196 
217 {
223  void *watch_data;
225 };
226 
235 {
236  DBusWatchList *watch_list;
237 
238  watch_list = dbus_new0 (DBusWatchList, 1);
239  if (watch_list == NULL)
240  return NULL;
241 
242  return watch_list;
243 }
244 
250 void
252 {
253  /* free watch_data and removes watches as a side effect */
254  _dbus_watch_list_set_functions (watch_list,
255  NULL, NULL, NULL, NULL, NULL);
256 
257  _dbus_list_clear_full (&watch_list->watches,
259 
260  dbus_free (watch_list);
261 }
262 
263 #ifdef DBUS_ENABLE_VERBOSE_MODE
264 static const char*
265 watch_flags_to_string (int flags)
266 {
267  const char *watch_type;
268 
269  if ((flags & DBUS_WATCH_READABLE) &&
270  (flags & DBUS_WATCH_WRITABLE))
271  watch_type = "readwrite";
272  else if (flags & DBUS_WATCH_READABLE)
273  watch_type = "read";
274  else if (flags & DBUS_WATCH_WRITABLE)
275  watch_type = "write";
276  else
277  watch_type = "not read or write";
278  return watch_type;
279 }
280 #endif /* DBUS_ENABLE_VERBOSE_MODE */
281 
298  DBusAddWatchFunction add_function,
299  DBusRemoveWatchFunction remove_function,
300  DBusWatchToggledFunction toggled_function,
301  void *data,
302  DBusFreeFunction free_data_function)
303 {
304  /* Add watches with the new watch function, failing on OOM */
305  if (add_function != NULL)
306  {
307  DBusList *link;
308 
309  link = _dbus_list_get_first_link (&watch_list->watches);
310  while (link != NULL)
311  {
312  DBusList *next = _dbus_list_get_next_link (&watch_list->watches,
313  link);
314 #ifdef DBUS_ENABLE_VERBOSE_MODE
315  DBusWatch *watch = link->data;
316 
317  _dbus_verbose ("Adding a %s watch on fd %" DBUS_POLLABLE_FORMAT " using newly-set add watch function\n",
318  watch_flags_to_string (dbus_watch_get_flags (link->data)),
319  _dbus_pollable_printable (watch->fd));
320 #endif
321 
322  if (!(* add_function) (link->data, data))
323  {
324  /* remove it all again and return FALSE */
325  DBusList *link2;
326 
327  link2 = _dbus_list_get_first_link (&watch_list->watches);
328  while (link2 != link)
329  {
330  DBusList *next2 = _dbus_list_get_next_link (&watch_list->watches,
331  link2);
332 #ifdef DBUS_ENABLE_VERBOSE_MODE
333  DBusWatch *watch2 = link2->data;
334 
335  _dbus_verbose ("Removing watch on fd %" DBUS_POLLABLE_FORMAT " using newly-set remove function because initial add failed\n",
336  _dbus_pollable_printable (watch2->fd));
337 #endif
338 
339  (* remove_function) (link2->data, data);
340 
341  link2 = next2;
342  }
343 
344  return FALSE;
345  }
346 
347  link = next;
348  }
349  }
350 
351  /* Remove all current watches from previous watch handlers */
352 
353  if (watch_list->remove_watch_function != NULL)
354  {
355  _dbus_verbose ("Removing all pre-existing watches\n");
356 
357  _dbus_list_foreach (&watch_list->watches,
359  watch_list->watch_data);
360  }
361 
362  if (watch_list->watch_free_data_function != NULL)
363  (* watch_list->watch_free_data_function) (watch_list->watch_data);
364 
365  watch_list->add_watch_function = add_function;
366  watch_list->remove_watch_function = remove_function;
367  watch_list->watch_toggled_function = toggled_function;
368  watch_list->watch_data = data;
369  watch_list->watch_free_data_function = free_data_function;
370 
371  return TRUE;
372 }
373 
384  DBusWatch *watch)
385 {
386  if (!_dbus_list_append (&watch_list->watches, watch))
387  return FALSE;
388 
389  _dbus_watch_ref (watch);
390 
391  if (watch_list->add_watch_function != NULL)
392  {
393  _dbus_verbose ("Adding watch on fd %" DBUS_POLLABLE_FORMAT "\n",
394  _dbus_pollable_printable (watch->fd));
395 
396  if (!(* watch_list->add_watch_function) (watch,
397  watch_list->watch_data))
398  {
399  _dbus_list_remove_last (&watch_list->watches, watch);
400  _dbus_watch_unref (watch);
401  return FALSE;
402  }
403  }
404 
405  return TRUE;
406 }
407 
415 void
417  DBusWatch *watch)
418 {
419  if (!_dbus_list_remove (&watch_list->watches, watch))
420  _dbus_assert_not_reached ("Nonexistent watch was removed");
421 
422  if (watch_list->remove_watch_function != NULL)
423  {
424  _dbus_verbose ("Removing watch on fd %" DBUS_POLLABLE_FORMAT "\n",
425  _dbus_pollable_printable (watch->fd));
426 
427  (* watch_list->remove_watch_function) (watch,
428  watch_list->watch_data);
429  }
430 
431  _dbus_watch_unref (watch);
432 }
433 
442 void
444  DBusWatch *watch,
445  dbus_bool_t enabled)
446 {
447  enabled = !!enabled;
448 
449  if (enabled == watch->enabled)
450  return;
451 
452  watch->enabled = enabled;
453 
454  if (watch_list->watch_toggled_function != NULL)
455  {
456  _dbus_verbose ("Toggling watch %p on fd %" DBUS_POLLABLE_FORMAT " to %d\n",
457  watch,
458  _dbus_pollable_printable (watch->fd),
459  watch->enabled);
460 
461  (* watch_list->watch_toggled_function) (watch,
462  watch_list->watch_data);
463  }
464 }
465 
473 void
475  dbus_bool_t enabled)
476 {
477  DBusList *link;
478 
479  for (link = _dbus_list_get_first_link (&watch_list->watches);
480  link != NULL;
481  link = _dbus_list_get_next_link (&watch_list->watches, link))
482  {
483  _dbus_watch_list_toggle_watch (watch_list, link->data, enabled);
484  }
485 }
486 
499 void
501  DBusWatchHandler handler,
502  void *data,
503  DBusFreeFunction free_data_function)
504 {
505  if (watch->free_handler_data_function)
506  (* watch->free_handler_data_function) (watch->handler_data);
507 
508  watch->handler = handler;
509  watch->handler_data = data;
510  watch->free_handler_data_function = free_data_function;
511 }
512 
544 int
546 {
547  _dbus_return_val_if_fail (watch != NULL, -1);
548 
549  return dbus_watch_get_unix_fd(watch);
550 }
551 
565 int
567 {
568  _dbus_return_val_if_fail (watch != NULL, -1);
569 
570  /* FIXME remove #ifdef and do this on a lower level
571  * (watch should have set_socket and set_unix_fd and track
572  * which it has, and the transport should provide the
573  * appropriate watch type)
574  */
575 #ifdef DBUS_UNIX
576  return watch->fd;
577 #else
578  return dbus_watch_get_socket( watch );
579 #endif
580 }
581 
594 int
596 {
597  _dbus_return_val_if_fail (watch != NULL, -1);
598 
599 #ifdef DBUS_UNIX
600  return watch->fd;
601 #else
602  return _dbus_socket_get_int (watch->fd);
603 #endif
604 }
605 
607 _dbus_watch_get_socket (DBusWatch *watch)
608 {
609  DBusSocket s;
610 
611  _dbus_assert (watch != NULL);
612 
613 #ifdef DBUS_UNIX
614  s.fd = watch->fd;
615 #else
616  s = watch->fd;
617 #endif
618 
619  return s;
620 }
621 
622 DBusPollable
623 _dbus_watch_get_pollable (DBusWatch *watch)
624 {
625  _dbus_assert (watch != NULL);
626 
627  return watch->fd;
628 }
629 
643 unsigned int
645 {
646  _dbus_return_val_if_fail (watch != NULL, 0);
647  _dbus_assert ((watch->flags & VALID_WATCH_FLAGS) == watch->flags);
648 
649  return watch->flags;
650 }
651 
659 void*
661 {
662  _dbus_return_val_if_fail (watch != NULL, NULL);
663 
664  return watch->data;
665 }
666 
678 void
680  void *data,
681  DBusFreeFunction free_data_function)
682 {
683  _dbus_return_if_fail (watch != NULL);
684 
685  _dbus_verbose ("Setting watch fd %" DBUS_POLLABLE_FORMAT " data to data = %p function = %p from data = %p function = %p\n",
686  _dbus_pollable_printable (watch->fd),
687  data, free_data_function, watch->data, watch->free_data_function);
688 
689  if (watch->free_data_function != NULL)
690  (* watch->free_data_function) (watch->data);
691 
692  watch->data = data;
693  watch->free_data_function = free_data_function;
694 }
695 
705 {
706  _dbus_return_val_if_fail (watch != NULL, FALSE);
707 
708  return watch->enabled;
709 }
710 
711 
736  unsigned int flags)
737 {
738  _dbus_return_val_if_fail (watch != NULL, FALSE);
739 
740 #ifndef DBUS_DISABLE_CHECKS
741  if (!_dbus_pollable_is_valid (watch->fd) || watch->flags == 0)
742  {
743  _dbus_warn_check_failed ("Watch is invalid, it should have been removed");
744  return TRUE;
745  }
746 #endif
747 
748  _dbus_return_val_if_fail (_dbus_pollable_is_valid (watch->fd) /* fails if watch was removed */, TRUE);
749 
750  _dbus_watch_sanitize_condition (watch, &flags);
751 
752  if (flags == 0)
753  {
754  _dbus_verbose ("After sanitization, watch flags on fd %" DBUS_POLLABLE_FORMAT " were 0\n",
755  _dbus_pollable_printable (watch->fd));
756  return TRUE;
757  }
758  else
759  return (* watch->handler) (watch, flags,
760  watch->handler_data);
761 }
762 
763 
DBusWatch * _dbus_watch_new(DBusPollable fd, unsigned int flags, dbus_bool_t enabled, DBusWatchHandler handler, void *data, DBusFreeFunction free_data_function)
Creates a new DBusWatch.
Definition: dbus-watch.c:90
Implementation of DBusWatch.
Definition: dbus-watch.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_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:710
DBusFreeFunction watch_free_data_function
Free function for watch callback data.
Definition: dbus-watch.c:224
void * handler_data
Watch handler data.
Definition: dbus-watch.c:49
void(* DBusWatchToggledFunction)(DBusWatch *watch, void *data)
Called when dbus_watch_get_enabled() may return a different value than it did before.
DBUS_EXPORT dbus_bool_t dbus_watch_get_enabled(DBusWatch *watch)
Returns whether a watch is enabled or not.
Definition: dbus-watch.c:704
void * data
Data stored at this element.
Definition: dbus-list.h:40
void _dbus_warn_check_failed(const char *format,...)
Prints a "critical" warning to stderr when an assertion fails; differs from _dbus_warn primarily in t...
dbus_bool_t(* DBusWatchHandler)(DBusWatch *watch, unsigned int flags, void *data)
function to run when the watch is handled
Definition: dbus-watch.h:45
void _dbus_watch_list_toggle_watch(DBusWatchList *watch_list, DBusWatch *watch, dbus_bool_t enabled)
Sets a watch to the given enabled state, invoking the application's DBusWatchToggledFunction if appro...
Definition: dbus-watch.c:443
DBusAddWatchFunction add_watch_function
Callback for adding a watch.
Definition: dbus-watch.c:220
DBusFreeFunction free_data_function
Free the application data.
Definition: dbus-watch.c:53
void _dbus_watch_list_free(DBusWatchList *watch_list)
Frees a DBusWatchList.
Definition: dbus-watch.c:251
void _dbus_list_clear_full(DBusList **list, DBusFreeFunction function)
Free every link and every element in the list.
Definition: dbus-list.c:570
DBusWatchToggledFunction watch_toggled_function
Callback on toggling enablement.
Definition: dbus-watch.c:222
DBusWatchList * _dbus_watch_list_new(void)
Creates a new watch list.
Definition: dbus-watch.c:234
void * watch_data
Data for watch callbacks.
Definition: dbus-watch.c:223
dbus_bool_t _dbus_list_remove(DBusList **list, void *data)
Removes a value from the list.
Definition: dbus-list.c:418
unsigned int flags
Conditions to watch.
Definition: dbus-watch.c:46
#define _dbus_list_get_next_link(list, link)
Gets the next link in the list, or NULL if there are no more links.
Definition: dbus-list.h:121
dbus_bool_t _dbus_watch_list_set_functions(DBusWatchList *watch_list, DBusAddWatchFunction add_function, DBusRemoveWatchFunction remove_function, DBusWatchToggledFunction toggled_function, void *data, DBusFreeFunction free_data_function)
Sets the watch functions.
Definition: dbus-watch.c:297
Socket interface.
Definition: dbus-sysdeps.h:185
dbus_bool_t _dbus_list_remove_last(DBusList **list, void *data)
Removes a value from the list.
Definition: dbus-list.c:449
#define dbus_new0(type, count)
Safe macro for using dbus_malloc0().
Definition: dbus-memory.h:60
As in POLLOUT.
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:37
DBUS_EXPORT int dbus_watch_get_socket(DBusWatch *watch)
Returns a socket to be watched, on UNIX this will return -1 if our transport is not socket-based so d...
Definition: dbus-watch.c:595
void _dbus_warn(const char *format,...)
Prints a warning message to stderr.
dbus_bool_t _dbus_list_append(DBusList **list, void *data)
Appends a value to the list.
Definition: dbus-list.c:273
void _dbus_watch_sanitize_condition(DBusWatch *watch, unsigned int *condition)
Sanitizes the given condition so that it only contains flags that the DBusWatch requested.
Definition: dbus-watch.c:187
void _dbus_list_foreach(DBusList **list, DBusForeachFunction function, void *data)
Calls the given function for each element in the list.
Definition: dbus-list.c:789
void _dbus_watch_list_toggle_all_watches(DBusWatchList *watch_list, dbus_bool_t enabled)
Sets all watches to the given enabled state, invoking the application's DBusWatchToggledFunction if a...
Definition: dbus-watch.c:474
void _dbus_watch_invalidate(DBusWatch *watch)
Clears the file descriptor from a now-invalid watch object so that no one tries to use it...
Definition: dbus-watch.c:171
#define _dbus_assert_not_reached(explanation)
Aborts with an error message if called.
unsigned int oom_last_time
Whether it was OOM last time.
Definition: dbus-watch.c:55
void * data
Application data.
Definition: dbus-watch.c:52
DBUS_EXPORT int dbus_watch_get_unix_fd(DBusWatch *watch)
Returns a UNIX file descriptor to be watched, which may be a pipe, socket, or other type of descripto...
Definition: dbus-watch.c:566
int refcount
Reference count.
Definition: dbus-watch.c:44
#define TRUE
Expands to "1".
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
dbus_bool_t _dbus_watch_list_add_watch(DBusWatchList *watch_list, DBusWatch *watch)
Adds a new watch to the watch list, invoking the application DBusAddWatchFunction if appropriate...
Definition: dbus-watch.c:383
DBUS_EXPORT DBUS_DEPRECATED int dbus_watch_get_fd(DBusWatch *watch)
Deprecated former name of dbus_watch_get_unix_fd().
Definition: dbus-watch.c:545
dbus_bool_t(* DBusAddWatchFunction)(DBusWatch *watch, void *data)
Called when libdbus needs a new watch to be monitored by the main loop.
DBUS_EXPORT void dbus_watch_set_data(DBusWatch *watch, void *data, DBusFreeFunction free_data_function)
Sets data which can be retrieved with dbus_watch_get_data().
Definition: dbus-watch.c:679
void(* DBusRemoveWatchFunction)(DBusWatch *watch, void *data)
Called when libdbus no longer needs a watch to be monitored by the main loop.
DBusWatchList implementation details.
Definition: dbus-watch.c:216
unsigned int enabled
Whether it's enabled.
Definition: dbus-watch.c:54
DBUS_EXPORT void * dbus_watch_get_data(DBusWatch *watch)
Gets data previously set with dbus_watch_set_data() or NULL if none.
Definition: dbus-watch.c:660
void _dbus_watch_list_remove_watch(DBusWatchList *watch_list, DBusWatch *watch)
Removes a watch from the watch list, invoking the application's DBusRemoveWatchFunction if appropriat...
Definition: dbus-watch.c:416
A node in a linked list.
Definition: dbus-list.h:36
void _dbus_watch_unref(DBusWatch *watch)
Decrements the reference count of a DBusWatch object and finalizes the object if the count reaches ze...
Definition: dbus-watch.c:140
void(* DBusForeachFunction)(void *element, void *data)
Used to iterate over each item in a collection, such as a DBusList.
DBusList * _dbus_list_get_first_link(DBusList **list)
Gets the first link in the list.
Definition: dbus-list.c:597
#define FALSE
Expands to "0".
DBUS_EXPORT dbus_bool_t dbus_watch_handle(DBusWatch *watch, unsigned int flags)
Called to notify the D-Bus library when a previously-added watch is ready for reading or writing...
Definition: dbus-watch.c:735
DBusWatch * _dbus_watch_ref(DBusWatch *watch)
Increments the reference count of a DBusWatch object.
Definition: dbus-watch.c:126
DBusPollable fd
File descriptor.
Definition: dbus-watch.c:45
DBUS_EXPORT unsigned int dbus_watch_get_flags(DBusWatch *watch)
Gets flags from DBusWatchFlags indicating what conditions should be monitored on the file descriptor...
Definition: dbus-watch.c:644
As in POLLIN.
DBusFreeFunction free_handler_data_function
Free the watch handler data.
Definition: dbus-watch.c:50
void _dbus_watch_set_handler(DBusWatch *watch, DBusWatchHandler handler, void *data, DBusFreeFunction free_data_function)
Sets the handler for the watch.
Definition: dbus-watch.c:500
DBusRemoveWatchFunction remove_watch_function
Callback for removing a watch.
Definition: dbus-watch.c:221
DBusWatchHandler handler
Watch handler.
Definition: dbus-watch.c:48
DBusList * watches
Watch objects.
Definition: dbus-watch.c:218