D-Bus  1.16.2
dbus-dataslot.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-dataslot.c storing data on objects
3  *
4  * Copyright (C) 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-dataslot.h"
28 #include "dbus-threads-internal.h"
29 #include <dbus/dbus-test-tap.h>
30 
50  DBusGlobalLock lock)
51 {
52  allocator->allocated_slots = NULL;
53  allocator->n_allocated_slots = 0;
54  allocator->n_used_slots = 0;
55  allocator->lock = lock;
56 
57  return TRUE;
58 }
59 
73  dbus_int32_t *slot_id_p)
74 {
75  dbus_int32_t slot;
76 
77  if (!_dbus_lock (allocator->lock))
78  return FALSE;
79 
80  if (*slot_id_p >= 0)
81  {
82  slot = *slot_id_p;
83 
84  _dbus_assert (slot < allocator->n_allocated_slots);
85  _dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
86 
87  allocator->allocated_slots[slot].refcount += 1;
88 
89  goto out;
90  }
91 
92  _dbus_assert (*slot_id_p < 0);
93 
94  if (allocator->n_used_slots < allocator->n_allocated_slots)
95  {
96  slot = 0;
97  while (slot < allocator->n_allocated_slots)
98  {
99  if (allocator->allocated_slots[slot].slot_id < 0)
100  {
101  allocator->allocated_slots[slot].slot_id = slot;
102  allocator->allocated_slots[slot].refcount = 1;
103  allocator->n_used_slots += 1;
104  break;
105  }
106  ++slot;
107  }
108 
109  _dbus_assert (slot < allocator->n_allocated_slots);
110  }
111  else
112  {
113  DBusAllocatedSlot *tmp;
114 
115  slot = -1;
116  tmp = dbus_realloc (allocator->allocated_slots,
117  sizeof (DBusAllocatedSlot) * (allocator->n_allocated_slots + 1));
118  if (tmp == NULL)
119  goto out;
120 
121  allocator->allocated_slots = tmp;
122  slot = allocator->n_allocated_slots;
123  allocator->n_allocated_slots += 1;
124  allocator->n_used_slots += 1;
125  allocator->allocated_slots[slot].slot_id = slot;
126  allocator->allocated_slots[slot].refcount = 1;
127  }
128 
129  _dbus_assert (slot >= 0);
130  _dbus_assert (slot < allocator->n_allocated_slots);
131  _dbus_assert (*slot_id_p < 0);
132  _dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
133  _dbus_assert (allocator->allocated_slots[slot].refcount == 1);
134 
135  *slot_id_p = slot;
136 
137  _dbus_verbose ("Allocated slot %d on allocator %p total %d slots allocated %d used\n",
138  slot, allocator, allocator->n_allocated_slots, allocator->n_used_slots);
139 
140  out:
141  _dbus_unlock (allocator->lock);
142  return slot >= 0;
143 }
144 
156 void
158  dbus_int32_t *slot_id_p)
159 {
160  if (!_dbus_lock (allocator->lock))
161  _dbus_assert_not_reached ("we should have initialized global locks "
162  "before we allocated this slot");
163 
164  _dbus_assert (*slot_id_p < allocator->n_allocated_slots);
165  _dbus_assert (allocator->allocated_slots[*slot_id_p].slot_id == *slot_id_p);
166  _dbus_assert (allocator->allocated_slots[*slot_id_p].refcount > 0);
167 
168  allocator->allocated_slots[*slot_id_p].refcount -= 1;
169 
170  if (allocator->allocated_slots[*slot_id_p].refcount > 0)
171  {
172  _dbus_unlock (allocator->lock);
173  return;
174  }
175 
176  /* refcount is 0, free the slot */
177  _dbus_verbose ("Freeing slot %d on allocator %p total %d allocated %d used\n",
178  *slot_id_p, allocator, allocator->n_allocated_slots, allocator->n_used_slots);
179 
180  allocator->allocated_slots[*slot_id_p].slot_id = -1;
181  *slot_id_p = -1;
182 
183  allocator->n_used_slots -= 1;
184 
185  if (allocator->n_used_slots == 0)
186  {
187  dbus_free (allocator->allocated_slots);
188  allocator->allocated_slots = NULL;
189  allocator->n_allocated_slots = 0;
190  }
191 
192  _dbus_unlock (allocator->lock);
193 }
194 
199 void
201 {
202  list->slots = NULL;
203  list->n_slots = 0;
204 }
205 
225  DBusDataSlotList *list,
226  int slot,
227  void *data,
228  DBusFreeFunction free_data_func,
229  DBusFreeFunction *old_free_func,
230  void **old_data)
231 {
232 #ifndef DBUS_DISABLE_ASSERT
233  /* We need to take the allocator lock here, because the allocator could
234  * be e.g. realloc()ing allocated_slots. We avoid doing this if asserts
235  * are disabled, since then the asserts are empty.
236  */
237  if (!_dbus_lock (allocator->lock))
238  _dbus_assert_not_reached ("we should have initialized global locks "
239  "before we allocated this slot");
240 
241  _dbus_assert (slot < allocator->n_allocated_slots);
242  _dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
243  _dbus_unlock (allocator->lock);
244 #endif
245 
246  if (slot >= list->n_slots)
247  {
248  DBusDataSlot *tmp;
249  int i;
250 
251  tmp = dbus_realloc (list->slots,
252  sizeof (DBusDataSlot) * (slot + 1));
253  if (tmp == NULL)
254  return FALSE;
255 
256  list->slots = tmp;
257  i = list->n_slots;
258  list->n_slots = slot + 1;
259  while (i < list->n_slots)
260  {
261  list->slots[i].data = NULL;
262  list->slots[i].free_data_func = NULL;
263  ++i;
264  }
265  }
266 
267  _dbus_assert (slot < list->n_slots);
268 
269  *old_data = list->slots[slot].data;
270  *old_free_func = list->slots[slot].free_data_func;
271 
272  list->slots[slot].data = data;
273  list->slots[slot].free_data_func = free_data_func;
274 
275  return TRUE;
276 }
277 
287 void*
289  DBusDataSlotList *list,
290  int slot)
291 {
292 #ifndef DBUS_DISABLE_ASSERT
293  /* We need to take the allocator lock here, because the allocator could
294  * be e.g. realloc()ing allocated_slots. We avoid doing this if asserts
295  * are disabled, since then the asserts are empty.
296  */
297  if (!_dbus_lock (allocator->lock))
298  _dbus_assert_not_reached ("we should have initialized global locks "
299  "before we allocated this slot");
300 
301  _dbus_assert (slot >= 0);
302  _dbus_assert (slot < allocator->n_allocated_slots);
303  _dbus_assert (allocator->allocated_slots[slot].slot_id == slot);
304  _dbus_unlock (allocator->lock);
305 #endif
306 
307  if (slot >= list->n_slots)
308  return NULL;
309  else
310  return list->slots[slot].data;
311 }
312 
319 void
321 {
322  int i;
323 
324  i = 0;
325  while (i < list->n_slots)
326  {
327  if (list->slots[i].free_data_func)
328  (* list->slots[i].free_data_func) (list->slots[i].data);
329  list->slots[i].data = NULL;
330  list->slots[i].free_data_func = NULL;
331  ++i;
332  }
333 }
334 
342 void
344 {
346 
347  dbus_free (list->slots);
348  list->slots = NULL;
349  list->n_slots = 0;
350 }
351 
354 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
355 #include "dbus-test.h"
356 #include <stdio.h>
357 
358 /* Test-only, does not need to be thread-safe */
359 static int free_counter;
360 
361 static void
362 test_free_slot_data_func (void *data)
363 {
364  int i = _DBUS_POINTER_TO_INT (data);
365 
366  _dbus_assert (free_counter == i);
367  ++free_counter;
368 }
369 
374 _dbus_data_slot_test (const char *test_data_dir _DBUS_GNUC_UNUSED)
375 {
376  DBusDataSlotAllocator allocator;
377  DBusDataSlotList list;
378  int i;
379  DBusFreeFunction old_free_func;
380  void *old_data;
381 
382  if (!_dbus_data_slot_allocator_init (&allocator, _DBUS_LOCK_server_slots))
383  _dbus_test_fatal ("no memory for allocator");
384 
386 
387 #define N_SLOTS 100
388 
389  i = 0;
390  while (i < N_SLOTS)
391  {
392  /* we don't really want apps to rely on this ordered
393  * allocation, but it simplifies things to rely on it
394  * here.
395  */
396  dbus_int32_t tmp = -1;
397 
398  _dbus_data_slot_allocator_alloc (&allocator, &tmp);
399 
400  if (tmp != i)
401  _dbus_test_fatal ("did not allocate slots in numeric order");
402 
403  ++i;
404  }
405 
406  i = 0;
407  while (i < N_SLOTS)
408  {
409  if (!_dbus_data_slot_list_set (&allocator, &list,
410  i,
412  test_free_slot_data_func,
413  &old_free_func, &old_data))
414  _dbus_test_fatal ("no memory to set data");
415 
416  _dbus_assert (old_free_func == NULL);
417  _dbus_assert (old_data == NULL);
418 
419  _dbus_assert (_dbus_data_slot_list_get (&allocator, &list, i) ==
421 
422  ++i;
423  }
424 
425  free_counter = 0;
426  i = 0;
427  while (i < N_SLOTS)
428  {
429  if (!_dbus_data_slot_list_set (&allocator, &list,
430  i,
432  test_free_slot_data_func,
433  &old_free_func, &old_data))
434  _dbus_test_fatal ("no memory to set data");
435 
436  _dbus_assert (old_free_func == test_free_slot_data_func);
437  _dbus_assert (_DBUS_POINTER_TO_INT (old_data) == i);
438 
439  (* old_free_func) (old_data);
440  _dbus_assert (i == (free_counter - 1));
441 
442  _dbus_assert (_dbus_data_slot_list_get (&allocator, &list, i) ==
444 
445  ++i;
446  }
447 
448  free_counter = 0;
450 
451  _dbus_assert (N_SLOTS == free_counter);
452 
453  i = 0;
454  while (i < N_SLOTS)
455  {
456  dbus_int32_t tmp = i;
457 
458  _dbus_data_slot_allocator_free (&allocator, &tmp);
459  _dbus_assert (tmp == -1);
460  ++i;
461  }
462 
463  return TRUE;
464 }
465 
466 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
DBusFreeFunction free_data_func
Free the application data.
Definition: dbus-dataslot.h:41
#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
int n_allocated_slots
number of slots malloc'd
Definition: dbus-dataslot.h:60
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:710
An allocated slot for storing data.
Definition: dbus-dataslot.h:48
#define _DBUS_INT_TO_POINTER(integer)
Safely stuffs an integer into a pointer, to be extracted later with _DBUS_POINTER_TO_INT.
int n_used_slots
number of slots used
Definition: dbus-dataslot.h:61
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:37
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...
DBusDataSlot * slots
Data slots.
Definition: dbus-dataslot.h:73
#define _DBUS_POINTER_TO_INT(pointer)
Safely casts a void* to an integer; should only be used on void* that actually contain integers...
void _dbus_data_slot_list_clear(DBusDataSlotList *list)
Frees all data slots contained in the list, calling application-provided free functions if they exist...
dbus_int32_t slot_id
ID of this slot.
Definition: dbus-dataslot.h:50
#define _dbus_assert_not_reached(explanation)
Aborts with an error message if called.
void * _dbus_data_slot_list_get(DBusDataSlotAllocator *allocator, DBusDataSlotList *list, int slot)
Retrieves data previously set with _dbus_data_slot_list_set_data().
#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.
An allocator that tracks a set of slot IDs.
Definition: dbus-dataslot.h:57
int refcount
Number of uses of the slot.
Definition: dbus-dataslot.h:51
int n_slots
Slots we have storage for in data_slots.
Definition: dbus-dataslot.h:74
#define FALSE
Expands to "0".
void * data
The application data.
Definition: dbus-dataslot.h:40
dbus_bool_t _dbus_data_slot_allocator_init(DBusDataSlotAllocator *allocator, DBusGlobalLock lock)
Initializes a data slot allocator object, used to assign integer IDs for data slots.
Definition: dbus-dataslot.c:49
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
void * dbus_realloc(void *memory, size_t bytes)
Resizes a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:610
int dbus_int32_t
A 32-bit signed integer on all platforms.
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().
DBusAllocatedSlot * allocated_slots
Allocated slots.
Definition: dbus-dataslot.h:59
DBusDataSlot is used to store application data on the connection.
Definition: dbus-dataslot.h:38
DBusGlobalLock lock
index of thread lock
Definition: dbus-dataslot.h:62
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...