1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-memory.c D-Bus memory handling
3 *
4 * Copyright (C) 2002, 2003 Red Hat Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23
24 #include <config.h>
25 #include "dbus-memory.h"
26 #include "dbus-internals.h"
27 #include "dbus-sysdeps.h"
28 #include "dbus-list.h"
29 #include "dbus-threads.h"
30 #include <stdlib.h>
31
32 /**
33 * @defgroup DBusMemory Memory Allocation
34 * @ingroup DBus
35 * @brief dbus_malloc(), dbus_free(), etc.
36 *
37 * Functions and macros related to allocating and releasing
38 * blocks of memory.
39 *
40 */
41
42 /**
43 * @defgroup DBusMemoryInternals Memory allocation implementation details
44 * @ingroup DBusInternals
45 * @brief internals of dbus_malloc() etc.
46 *
47 * Implementation details related to allocating and releasing blocks
48 * of memory.
49 */
50
51 /**
52 * @addtogroup DBusMemory
53 *
54 * @{
55 */
56
57 /**
58 * @def dbus_new
59 *
60 * Safe macro for using dbus_malloc(). Accepts the type
61 * to allocate and the number of type instances to
62 * allocate as arguments, and returns a memory block
63 * cast to the desired type, instead of as a void*.
64 *
65 * @param type type name to allocate
66 * @param count number of instances in the allocated array
67 * @returns the new memory block or #NULL on failure
68 */
69
70 /**
71 * @def dbus_new0
72 *
73 * Safe macro for using dbus_malloc0(). Accepts the type
74 * to allocate and the number of type instances to
75 * allocate as arguments, and returns a memory block
76 * cast to the desired type, instead of as a void*.
77 * The allocated array is initialized to all-bits-zero.
78 *
79 * @param type type name to allocate
80 * @param count number of instances in the allocated array
81 * @returns the new memory block or #NULL on failure
82 */
83
84 /**
85 * @typedef DBusFreeFunction
86 *
87 * The type of a function which frees a block of memory.
88 *
89 * @param memory the memory to free
90 */
91
92 /** @} */ /* end of public API docs */
93
94 /**
95 * @addtogroup DBusMemoryInternals
96 *
97 * @{
98 */
99
100 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
101 static dbus_bool_t debug_initialized = FALSE;
102 static int fail_nth = -1;
103 static size_t fail_size = 0;
104 static int fail_alloc_counter = _DBUS_INT_MAX;
105 static int n_failures_per_failure = 1;
106 static int n_failures_this_failure = 0;
107 static dbus_bool_t guards = FALSE;
108 static dbus_bool_t disable_mem_pools = FALSE;
109 static dbus_bool_t backtrace_on_fail_alloc = FALSE;
110 static dbus_bool_t malloc_cannot_fail = FALSE;
111 static DBusAtomic n_blocks_outstanding = {0};
112
113 /** value stored in guard padding for debugging buffer overrun */
114 #define GUARD_VALUE 0xdeadbeef
115 /** size of the information about the block stored in guard mode */
116 #define GUARD_INFO_SIZE 8
117 /** size of the GUARD_VALUE-filled padding after the header info */
118 #define GUARD_START_PAD 16
119 /** size of the GUARD_VALUE-filled padding at the end of the block */
120 #define GUARD_END_PAD 16
121 /** size of stuff at start of block */
122 #define GUARD_START_OFFSET (GUARD_START_PAD + GUARD_INFO_SIZE)
123 /** total extra size over the requested allocation for guard stuff */
124 #define GUARD_EXTRA_SIZE (GUARD_START_OFFSET + GUARD_END_PAD)
125
126 static void
_dbus_initialize_malloc_debug(void)127 _dbus_initialize_malloc_debug (void)
128 {
129 if (!debug_initialized)
130 {
131 debug_initialized = TRUE;
132
133 if (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH") != NULL)
134 {
135 fail_nth = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH"));
136 fail_alloc_counter = fail_nth;
137 _dbus_verbose ("Will fail dbus_malloc every %d times\n", fail_nth);
138 }
139
140 if (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN") != NULL)
141 {
142 fail_size = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN"));
143 _dbus_verbose ("Will fail mallocs over %ld bytes\n",
144 (long) fail_size);
145 }
146
147 if (_dbus_getenv ("DBUS_MALLOC_GUARDS") != NULL)
148 {
149 guards = TRUE;
150 _dbus_verbose ("Will use dbus_malloc guards\n");
151 }
152
153 if (_dbus_getenv ("DBUS_DISABLE_MEM_POOLS") != NULL)
154 {
155 disable_mem_pools = TRUE;
156 _dbus_verbose ("Will disable memory pools\n");
157 }
158
159 if (_dbus_getenv ("DBUS_MALLOC_BACKTRACES") != NULL)
160 {
161 backtrace_on_fail_alloc = TRUE;
162 _dbus_verbose ("Will backtrace on failing a dbus_malloc\n");
163 }
164
165 if (_dbus_getenv ("DBUS_MALLOC_CANNOT_FAIL") != NULL)
166 {
167 malloc_cannot_fail = TRUE;
168 _dbus_verbose ("Will abort if system malloc() and friends fail\n");
169 }
170 }
171 }
172
173 /**
174 * Whether to turn off mem pools, useful for leak checking.
175 *
176 * @returns #TRUE if mempools should not be used.
177 */
178 dbus_bool_t
_dbus_disable_mem_pools(void)179 _dbus_disable_mem_pools (void)
180 {
181 _dbus_initialize_malloc_debug ();
182 return disable_mem_pools;
183 }
184
185 /**
186 * Sets the number of allocations until we simulate a failed
187 * allocation. If set to 0, the next allocation to run
188 * fails; if set to 1, one succeeds then the next fails; etc.
189 * Set to _DBUS_INT_MAX to not fail anything.
190 *
191 * @param until_next_fail number of successful allocs before one fails
192 */
193 void
_dbus_set_fail_alloc_counter(int until_next_fail)194 _dbus_set_fail_alloc_counter (int until_next_fail)
195 {
196 _dbus_initialize_malloc_debug ();
197
198 fail_alloc_counter = until_next_fail;
199
200 #if 0
201 _dbus_verbose ("Set fail alloc counter = %d\n", fail_alloc_counter);
202 #endif
203 }
204
205 /**
206 * Gets the number of successful allocs until we'll simulate
207 * a failed alloc.
208 *
209 * @returns current counter value
210 */
211 int
_dbus_get_fail_alloc_counter(void)212 _dbus_get_fail_alloc_counter (void)
213 {
214 _dbus_initialize_malloc_debug ();
215
216 return fail_alloc_counter;
217 }
218
219 /**
220 * Sets how many mallocs to fail when the fail alloc counter reaches
221 * 0.
222 *
223 * @param failures_per_failure number to fail
224 */
225 void
_dbus_set_fail_alloc_failures(int failures_per_failure)226 _dbus_set_fail_alloc_failures (int failures_per_failure)
227 {
228 n_failures_per_failure = failures_per_failure;
229 }
230
231 /**
232 * Gets the number of failures we'll have when the fail malloc
233 * counter reaches 0.
234 *
235 * @returns number of failures planned
236 */
237 int
_dbus_get_fail_alloc_failures(void)238 _dbus_get_fail_alloc_failures (void)
239 {
240 return n_failures_per_failure;
241 }
242
243 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
244 /**
245 * Called when about to alloc some memory; if
246 * it returns #TRUE, then the allocation should
247 * fail. If it returns #FALSE, then the allocation
248 * should not fail.
249 *
250 * @returns #TRUE if this alloc should fail
251 */
252 dbus_bool_t
_dbus_decrement_fail_alloc_counter(void)253 _dbus_decrement_fail_alloc_counter (void)
254 {
255 _dbus_initialize_malloc_debug ();
256 #ifdef DBUS_WIN_FIXME
257 {
258 static dbus_bool_t called = 0;
259
260 if (!called)
261 {
262 _dbus_verbose("TODO: memory allocation testing errors disabled for now\n");
263 called = 1;
264 }
265 return FALSE;
266 }
267 #endif
268
269 if (fail_alloc_counter <= 0)
270 {
271 if (backtrace_on_fail_alloc)
272 _dbus_print_backtrace ();
273
274 _dbus_verbose ("failure %d\n", n_failures_this_failure);
275
276 n_failures_this_failure += 1;
277 if (n_failures_this_failure >= n_failures_per_failure)
278 {
279 if (fail_nth >= 0)
280 fail_alloc_counter = fail_nth;
281 else
282 fail_alloc_counter = _DBUS_INT_MAX;
283
284 n_failures_this_failure = 0;
285
286 _dbus_verbose ("reset fail alloc counter to %d\n", fail_alloc_counter);
287 }
288
289 return TRUE;
290 }
291 else
292 {
293 fail_alloc_counter -= 1;
294 return FALSE;
295 }
296 }
297 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
298
299 /**
300 * Get the number of outstanding malloc()'d blocks.
301 *
302 * @returns number of blocks
303 */
304 int
_dbus_get_malloc_blocks_outstanding(void)305 _dbus_get_malloc_blocks_outstanding (void)
306 {
307 return _dbus_atomic_get (&n_blocks_outstanding);
308 }
309
310 /**
311 * Where the block came from.
312 */
313 typedef enum
314 {
315 SOURCE_UNKNOWN,
316 SOURCE_MALLOC,
317 SOURCE_REALLOC,
318 SOURCE_MALLOC_ZERO,
319 SOURCE_REALLOC_NULL
320 } BlockSource;
321
322 static const char*
source_string(BlockSource source)323 source_string (BlockSource source)
324 {
325 switch (source)
326 {
327 case SOURCE_UNKNOWN:
328 return "unknown";
329 case SOURCE_MALLOC:
330 return "malloc";
331 case SOURCE_REALLOC:
332 return "realloc";
333 case SOURCE_MALLOC_ZERO:
334 return "malloc0";
335 case SOURCE_REALLOC_NULL:
336 return "realloc(NULL)";
337 default:
338 _dbus_assert_not_reached ("Invalid malloc block source ID");
339 return "invalid!";
340 }
341 }
342
343 static void
check_guards(void * free_block,dbus_bool_t overwrite)344 check_guards (void *free_block,
345 dbus_bool_t overwrite)
346 {
347 if (free_block != NULL)
348 {
349 unsigned char *block = ((unsigned char*)free_block) - GUARD_START_OFFSET;
350 size_t requested_bytes = *(dbus_uint32_t*)block;
351 BlockSource source = *(dbus_uint32_t*)(block + 4);
352 unsigned int i;
353 dbus_bool_t failed;
354
355 failed = FALSE;
356
357 #if 0
358 _dbus_verbose ("Checking %d bytes request from source %s\n",
359 requested_bytes, source_string (source));
360 #endif
361
362 i = GUARD_INFO_SIZE;
363 while (i < GUARD_START_OFFSET)
364 {
365 dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
366 if (value != GUARD_VALUE)
367 {
368 _dbus_warn ("Block of %lu bytes from %s had start guard value 0x%ux at %d expected 0x%x",
369 (long) requested_bytes, source_string (source),
370 value, i, GUARD_VALUE);
371 failed = TRUE;
372 }
373
374 i += 4;
375 }
376
377 i = GUARD_START_OFFSET + requested_bytes;
378 while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
379 {
380 dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
381 if (value != GUARD_VALUE)
382 {
383 _dbus_warn ("Block of %lu bytes from %s had end guard value 0x%ux at %d expected 0x%x",
384 (long) requested_bytes, source_string (source),
385 value, i, GUARD_VALUE);
386 failed = TRUE;
387 }
388
389 i += 4;
390 }
391
392 /* set memory to anything but nul bytes */
393 if (overwrite)
394 memset (free_block, 'g', requested_bytes);
395
396 if (failed)
397 _dbus_assert_not_reached ("guard value corruption");
398 }
399 }
400
401 static void*
set_guards(void * real_block,size_t requested_bytes,BlockSource source)402 set_guards (void *real_block,
403 size_t requested_bytes,
404 BlockSource source)
405 {
406 unsigned char *block = real_block;
407 unsigned int i;
408
409 if (block == NULL)
410 return NULL;
411
412 _dbus_assert (GUARD_START_OFFSET + GUARD_END_PAD == GUARD_EXTRA_SIZE);
413
414 *((dbus_uint32_t*)block) = requested_bytes;
415 *((dbus_uint32_t*)(block + 4)) = source;
416
417 i = GUARD_INFO_SIZE;
418 while (i < GUARD_START_OFFSET)
419 {
420 (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
421
422 i += 4;
423 }
424
425 i = GUARD_START_OFFSET + requested_bytes;
426 while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
427 {
428 (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
429
430 i += 4;
431 }
432
433 check_guards (block + GUARD_START_OFFSET, FALSE);
434
435 return block + GUARD_START_OFFSET;
436 }
437
438 #endif
439
440 /** @} */ /* End of internals docs */
441
442
443 /**
444 * @addtogroup DBusMemory
445 *
446 * @{
447 */
448
449 /**
450 * Allocates the given number of bytes, as with standard
451 * malloc(). Guaranteed to return #NULL if bytes is zero
452 * on all platforms. Returns #NULL if the allocation fails.
453 * The memory must be released with dbus_free().
454 *
455 * dbus_malloc() memory is NOT safe to free with regular free() from
456 * the C library. Free it with dbus_free() only.
457 *
458 * @param bytes number of bytes to allocate
459 * @return allocated memory, or #NULL if the allocation fails.
460 */
461 void*
dbus_malloc(size_t bytes)462 dbus_malloc (size_t bytes)
463 {
464 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
465 _dbus_initialize_malloc_debug ();
466
467 if (_dbus_decrement_fail_alloc_counter ())
468 {
469 _dbus_verbose (" FAILING malloc of %ld bytes\n", (long) bytes);
470 return NULL;
471 }
472 #endif
473
474 if (bytes == 0) /* some system mallocs handle this, some don't */
475 return NULL;
476 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
477 else if (fail_size != 0 && bytes > fail_size)
478 return NULL;
479 else if (guards)
480 {
481 void *block;
482
483 block = malloc (bytes + GUARD_EXTRA_SIZE);
484 if (block)
485 {
486 _dbus_atomic_inc (&n_blocks_outstanding);
487 }
488 else if (malloc_cannot_fail)
489 {
490 _dbus_warn ("out of memory: malloc (%ld + %ld)",
491 (long) bytes, (long) GUARD_EXTRA_SIZE);
492 _dbus_abort ();
493 }
494
495 return set_guards (block, bytes, SOURCE_MALLOC);
496 }
497 #endif
498 else
499 {
500 void *mem;
501 mem = malloc (bytes);
502
503 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
504 if (mem)
505 {
506 _dbus_atomic_inc (&n_blocks_outstanding);
507 }
508 else if (malloc_cannot_fail)
509 {
510 _dbus_warn ("out of memory: malloc (%ld)", (long) bytes);
511 _dbus_abort ();
512 }
513 #endif
514
515 return mem;
516 }
517 }
518
519 /**
520 * Allocates the given number of bytes, as with standard malloc(), but
521 * all bytes are initialized to zero as with calloc(). Guaranteed to
522 * return #NULL if bytes is zero on all platforms. Returns #NULL if the
523 * allocation fails. The memory must be released with dbus_free().
524 *
525 * dbus_malloc0() memory is NOT safe to free with regular free() from
526 * the C library. Free it with dbus_free() only.
527 *
528 * @param bytes number of bytes to allocate
529 * @return allocated memory, or #NULL if the allocation fails.
530 */
531 void*
dbus_malloc0(size_t bytes)532 dbus_malloc0 (size_t bytes)
533 {
534 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
535 _dbus_initialize_malloc_debug ();
536
537 if (_dbus_decrement_fail_alloc_counter ())
538 {
539 _dbus_verbose (" FAILING malloc0 of %ld bytes\n", (long) bytes);
540
541 return NULL;
542 }
543 #endif
544
545 if (bytes == 0)
546 return NULL;
547 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
548 else if (fail_size != 0 && bytes > fail_size)
549 return NULL;
550 else if (guards)
551 {
552 void *block;
553
554 block = calloc (bytes + GUARD_EXTRA_SIZE, 1);
555
556 if (block)
557 {
558 _dbus_atomic_inc (&n_blocks_outstanding);
559 }
560 else if (malloc_cannot_fail)
561 {
562 _dbus_warn ("out of memory: calloc (%ld + %ld, 1)",
563 (long) bytes, (long) GUARD_EXTRA_SIZE);
564 _dbus_abort ();
565 }
566
567 return set_guards (block, bytes, SOURCE_MALLOC_ZERO);
568 }
569 #endif
570 else
571 {
572 void *mem;
573 mem = calloc (bytes, 1);
574
575 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
576 if (mem)
577 {
578 _dbus_atomic_inc (&n_blocks_outstanding);
579 }
580 else if (malloc_cannot_fail)
581 {
582 _dbus_warn ("out of memory: calloc (%ld)", (long) bytes);
583 _dbus_abort ();
584 }
585 #endif
586
587 return mem;
588 }
589 }
590
591 /**
592 * Resizes a block of memory previously allocated by dbus_malloc() or
593 * dbus_malloc0(). Guaranteed to free the memory and return #NULL if bytes
594 * is zero on all platforms. Returns #NULL if the resize fails.
595 * If the resize fails, the memory is not freed.
596 *
597 * @param memory block to be resized
598 * @param bytes new size of the memory block
599 * @return allocated memory, or #NULL if the resize fails.
600 */
601 void*
dbus_realloc(void * memory,size_t bytes)602 dbus_realloc (void *memory,
603 size_t bytes)
604 {
605 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
606 _dbus_initialize_malloc_debug ();
607
608 if (_dbus_decrement_fail_alloc_counter ())
609 {
610 _dbus_verbose (" FAILING realloc of %ld bytes\n", (long) bytes);
611
612 return NULL;
613 }
614 #endif
615
616 if (bytes == 0) /* guarantee this is safe */
617 {
618 dbus_free (memory);
619 return NULL;
620 }
621 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
622 else if (fail_size != 0 && bytes > fail_size)
623 return NULL;
624 else if (guards)
625 {
626 if (memory)
627 {
628 size_t old_bytes;
629 void *block;
630
631 check_guards (memory, FALSE);
632
633 block = realloc (((unsigned char*)memory) - GUARD_START_OFFSET,
634 bytes + GUARD_EXTRA_SIZE);
635
636 if (block == NULL)
637 {
638 if (malloc_cannot_fail)
639 {
640 _dbus_warn ("out of memory: realloc (%p, %ld + %ld)",
641 memory, (long) bytes, (long) GUARD_EXTRA_SIZE);
642 _dbus_abort ();
643 }
644
645 return NULL;
646 }
647
648 old_bytes = *(dbus_uint32_t*)block;
649 if (bytes >= old_bytes)
650 /* old guards shouldn't have moved */
651 check_guards (((unsigned char*)block) + GUARD_START_OFFSET, FALSE);
652
653 return set_guards (block, bytes, SOURCE_REALLOC);
654 }
655 else
656 {
657 void *block;
658
659 block = malloc (bytes + GUARD_EXTRA_SIZE);
660
661 if (block)
662 {
663 _dbus_atomic_inc (&n_blocks_outstanding);
664 }
665 else if (malloc_cannot_fail)
666 {
667 _dbus_warn ("out of memory: malloc (%ld + %ld)",
668 (long) bytes, (long) GUARD_EXTRA_SIZE);
669 _dbus_abort ();
670 }
671
672 return set_guards (block, bytes, SOURCE_REALLOC_NULL);
673 }
674 }
675 #endif
676 else
677 {
678 void *mem;
679 mem = realloc (memory, bytes);
680
681 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
682 if (mem == NULL && malloc_cannot_fail)
683 {
684 _dbus_warn ("out of memory: malloc (%ld)", (long) bytes);
685 _dbus_abort ();
686 }
687
688 if (memory == NULL && mem != NULL)
689 _dbus_atomic_inc (&n_blocks_outstanding);
690 #endif
691 return mem;
692 }
693 }
694
695 /**
696 * Frees a block of memory previously allocated by dbus_malloc() or
697 * dbus_malloc0(). If passed #NULL, does nothing.
698 *
699 * @param memory block to be freed
700 */
701 void
dbus_free(void * memory)702 dbus_free (void *memory)
703 {
704 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
705 if (guards)
706 {
707 check_guards (memory, TRUE);
708 if (memory)
709 {
710 #ifdef DBUS_DISABLE_ASSERT
711 _dbus_atomic_dec (&n_blocks_outstanding);
712 #else
713 dbus_int32_t old_value;
714
715 old_value = _dbus_atomic_dec (&n_blocks_outstanding);
716 _dbus_assert (old_value >= 1);
717 #endif
718
719 free (((unsigned char*)memory) - GUARD_START_OFFSET);
720 }
721
722 return;
723 }
724 #endif
725
726 if (memory) /* we guarantee it's safe to free (NULL) */
727 {
728 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
729 #ifdef DBUS_DISABLE_ASSERT
730 _dbus_atomic_dec (&n_blocks_outstanding);
731 #else
732 dbus_int32_t old_value;
733
734 old_value = _dbus_atomic_dec (&n_blocks_outstanding);
735 _dbus_assert (old_value >= 1);
736 #endif
737 #endif
738
739 free (memory);
740 }
741 }
742
743 /**
744 * Frees a #NULL-terminated array of strings.
745 * If passed #NULL, does nothing.
746 *
747 * @param str_array the array to be freed
748 */
749 void
dbus_free_string_array(char ** str_array)750 dbus_free_string_array (char **str_array)
751 {
752 if (str_array)
753 {
754 int i;
755
756 i = 0;
757 while (str_array[i])
758 {
759 dbus_free (str_array[i]);
760 i++;
761 }
762
763 dbus_free (str_array);
764 }
765 }
766
767 /** @} */ /* End of public API docs block */
768
769
770 /**
771 * @addtogroup DBusMemoryInternals
772 *
773 * @{
774 */
775
776 /**
777 * _dbus_current_generation is used to track each
778 * time that dbus_shutdown() is called, so we can
779 * reinit things after it's been called. It is simply
780 * incremented each time we shut down.
781 */
782 int _dbus_current_generation = 1;
783
784 /**
785 * Represents a function to be called on shutdown.
786 */
787 typedef struct ShutdownClosure ShutdownClosure;
788
789 /**
790 * This struct represents a function to be called on shutdown.
791 */
792 struct ShutdownClosure
793 {
794 ShutdownClosure *next; /**< Next ShutdownClosure */
795 DBusShutdownFunction func; /**< Function to call */
796 void *data; /**< Data for function */
797 };
798
799 /* Protected by _DBUS_LOCK (shutdown_funcs) */
800 static ShutdownClosure *registered_globals = NULL;
801
802 /**
803 * Register a cleanup function to be called exactly once
804 * the next time dbus_shutdown() is called.
805 *
806 * @param func the function
807 * @param data data to pass to the function
808 * @returns #FALSE on not enough memory
809 */
810 dbus_bool_t
_dbus_register_shutdown_func(DBusShutdownFunction func,void * data)811 _dbus_register_shutdown_func (DBusShutdownFunction func,
812 void *data)
813 {
814 dbus_bool_t ok;
815
816 if (!_DBUS_LOCK (shutdown_funcs))
817 return FALSE;
818
819 ok = _dbus_register_shutdown_func_unlocked (func, data);
820 _DBUS_UNLOCK (shutdown_funcs);
821 return ok;
822 }
823
824 dbus_bool_t
_dbus_register_shutdown_func_unlocked(DBusShutdownFunction func,void * data)825 _dbus_register_shutdown_func_unlocked (DBusShutdownFunction func,
826 void *data)
827 {
828 ShutdownClosure *c;
829
830 c = dbus_new (ShutdownClosure, 1);
831
832 if (c == NULL)
833 return FALSE;
834
835 c->func = func;
836 c->data = data;
837
838 c->next = registered_globals;
839 registered_globals = c;
840
841 return TRUE;
842 }
843
844 /** @} */ /* End of private API docs block */
845
846
847 /**
848 * @addtogroup DBusMemory
849 *
850 * @{
851 */
852
853 /**
854 * Frees all memory allocated internally by libdbus and
855 * reverses the effects of dbus_threads_init(). libdbus keeps internal
856 * global variables, for example caches and thread locks, and it
857 * can be useful to free these internal data structures.
858 *
859 * dbus_shutdown() does NOT free memory that was returned
860 * to the application. It only frees libdbus-internal
861 * data structures.
862 *
863 * You MUST free all memory and release all reference counts
864 * returned to you by libdbus prior to calling dbus_shutdown().
865 *
866 * If a shared connection is open, calling dbus_shutdown() will
867 * drain its queue of messages and disconnect it. In particular,
868 * this will result in processing of the special Disconnected
869 * signal, which may result in a call to _exit(), unless you
870 * have used dbus_connection_set_exit_on_disconnect() to disable
871 * that behaviour.
872 *
873 * You can't continue to use any D-Bus objects, such as connections,
874 * that were allocated prior to dbus_shutdown(). You can, however,
875 * start over; call dbus_threads_init() again, create new connections,
876 * and so forth.
877 *
878 * WARNING: dbus_shutdown() is NOT thread safe, it must be called
879 * while NO other threads are using D-Bus. (Remember, you have to free
880 * all D-Bus objects and memory before you call dbus_shutdown(), so no
881 * thread can be using libdbus.)
882 *
883 * The purpose of dbus_shutdown() is to allow applications to get
884 * clean output from memory leak checkers. dbus_shutdown() may also be
885 * useful if you want to dlopen() libdbus instead of linking to it,
886 * and want to be able to unload the library again.
887 *
888 * There is absolutely no requirement to call dbus_shutdown() - in fact,
889 * most applications won't bother and should not feel guilty.
890 *
891 * You have to know that nobody is using libdbus in your application's
892 * process before you can call dbus_shutdown(). One implication of this
893 * is that calling dbus_shutdown() from a library is almost certainly
894 * wrong, since you don't know what the rest of the app is up to.
895 *
896 */
897 void
dbus_shutdown(void)898 dbus_shutdown (void)
899 {
900 while (registered_globals != NULL)
901 {
902 ShutdownClosure *c;
903
904 c = registered_globals;
905 registered_globals = c->next;
906
907 (* c->func) (c->data);
908
909 dbus_free (c);
910 }
911
912 /* We wrap this in the thread-initialization lock because
913 * dbus_threads_init() uses the current generation to tell whether
914 * we're initialized, so we need to make sure that un-initializing
915 * propagates into all threads. */
916 _dbus_threads_lock_platform_specific ();
917 _dbus_current_generation += 1;
918 _dbus_threads_unlock_platform_specific ();
919 }
920
921 /** @} */ /** End of public API docs block */
922
923 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
924 #include "dbus-test.h"
925
926 /**
927 * @ingroup DBusMemoryInternals
928 * Unit test for DBusMemory
929 * @returns #TRUE on success.
930 */
931 dbus_bool_t
_dbus_memory_test(void)932 _dbus_memory_test (void)
933 {
934 dbus_bool_t old_guards;
935 void *p;
936 size_t size;
937
938 old_guards = guards;
939 guards = TRUE;
940 p = dbus_malloc (4);
941 if (p == NULL)
942 _dbus_assert_not_reached ("no memory");
943 for (size = 4; size < 256; size += 4)
944 {
945 p = dbus_realloc (p, size);
946 if (p == NULL)
947 _dbus_assert_not_reached ("no memory");
948 }
949 for (size = 256; size != 0; size -= 4)
950 {
951 p = dbus_realloc (p, size);
952 if (p == NULL)
953 _dbus_assert_not_reached ("no memory");
954 }
955 dbus_free (p);
956 guards = old_guards;
957 return TRUE;
958 }
959
960 #endif
961