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1 /* -*- mode: C; c-file-style: "gnu" -*- */
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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  *
22  */
23 
24 #include "dbus-memory.h"
25 #include "dbus-internals.h"
26 #include "dbus-sysdeps.h"
27 #include "dbus-list.h"
28 #include <stdlib.h>
29 
30 /**
31  * @defgroup DBusMemory Memory Allocation
32  * @ingroup  DBus
33  * @brief dbus_malloc(), dbus_free(), etc.
34  *
35  * Functions and macros related to allocating and releasing
36  * blocks of memory.
37  *
38  */
39 
40 /**
41  * @defgroup DBusMemoryInternals Memory allocation implementation details
42  * @ingroup  DBusInternals
43  * @brief internals of dbus_malloc() etc.
44  *
45  * Implementation details related to allocating and releasing blocks
46  * of memory.
47  */
48 
49 /**
50  * @addtogroup DBusMemory
51  *
52  * @{
53  */
54 
55 /**
56  * @def dbus_new
57  *
58  * Safe macro for using dbus_malloc(). Accepts the type
59  * to allocate and the number of type instances to
60  * allocate as arguments, and returns a memory block
61  * cast to the desired type, instead of as a void*.
62  *
63  * @param type type name to allocate
64  * @param count number of instances in the allocated array
65  * @returns the new memory block or #NULL on failure
66  */
67 
68 /**
69  * @def dbus_new0
70  *
71  * Safe macro for using dbus_malloc0(). Accepts the type
72  * to allocate and the number of type instances to
73  * allocate as arguments, and returns a memory block
74  * cast to the desired type, instead of as a void*.
75  * The allocated array is initialized to all-bits-zero.
76  *
77  * @param type type name to allocate
78  * @param count number of instances in the allocated array
79  * @returns the new memory block or #NULL on failure
80  */
81 
82 /**
83  * @typedef DBusFreeFunction
84  *
85  * The type of a function which frees a block of memory.
86  *
87  * @param memory the memory to free
88  */
89 
90 /** @} */ /* end of public API docs */
91 
92 /**
93  * @addtogroup DBusMemoryInternals
94  *
95  * @{
96  */
97 
98 #ifdef DBUS_BUILD_TESTS
99 static dbus_bool_t debug_initialized = FALSE;
100 static int fail_nth = -1;
101 static size_t fail_size = 0;
102 static int fail_alloc_counter = _DBUS_INT_MAX;
103 static int n_failures_per_failure = 1;
104 static int n_failures_this_failure = 0;
105 static dbus_bool_t guards = FALSE;
106 static dbus_bool_t disable_mem_pools = FALSE;
107 static dbus_bool_t backtrace_on_fail_alloc = FALSE;
108 static DBusAtomic n_blocks_outstanding = {0};
109 
110 /** value stored in guard padding for debugging buffer overrun */
111 #define GUARD_VALUE 0xdeadbeef
112 /** size of the information about the block stored in guard mode */
113 #define GUARD_INFO_SIZE 8
114 /** size of the GUARD_VALUE-filled padding after the header info  */
115 #define GUARD_START_PAD 16
116 /** size of the GUARD_VALUE-filled padding at the end of the block */
117 #define GUARD_END_PAD 16
118 /** size of stuff at start of block */
119 #define GUARD_START_OFFSET (GUARD_START_PAD + GUARD_INFO_SIZE)
120 /** total extra size over the requested allocation for guard stuff */
121 #define GUARD_EXTRA_SIZE (GUARD_START_OFFSET + GUARD_END_PAD)
122 
123 static void
_dbus_initialize_malloc_debug(void)124 _dbus_initialize_malloc_debug (void)
125 {
126   if (!debug_initialized)
127     {
128       debug_initialized = TRUE;
129 
130       if (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH") != NULL)
131 	{
132 	  fail_nth = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH"));
133           fail_alloc_counter = fail_nth;
134           _dbus_verbose ("Will fail malloc every %d times\n", fail_nth);
135 	}
136 
137       if (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN") != NULL)
138         {
139           fail_size = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN"));
140           _dbus_verbose ("Will fail mallocs over %ld bytes\n",
141                          (long) fail_size);
142         }
143 
144       if (_dbus_getenv ("DBUS_MALLOC_GUARDS") != NULL)
145         {
146           guards = TRUE;
147           _dbus_verbose ("Will use malloc guards\n");
148         }
149 
150       if (_dbus_getenv ("DBUS_DISABLE_MEM_POOLS") != NULL)
151         {
152           disable_mem_pools = TRUE;
153           _dbus_verbose ("Will disable memory pools\n");
154         }
155 
156       if (_dbus_getenv ("DBUS_MALLOC_BACKTRACES") != NULL)
157         {
158           backtrace_on_fail_alloc = TRUE;
159           _dbus_verbose ("Will backtrace on failing a malloc\n");
160         }
161     }
162 }
163 
164 /**
165  * Whether to turn off mem pools, useful for leak checking.
166  *
167  * @returns #TRUE if mempools should not be used.
168  */
169 dbus_bool_t
_dbus_disable_mem_pools(void)170 _dbus_disable_mem_pools (void)
171 {
172   _dbus_initialize_malloc_debug ();
173   return disable_mem_pools;
174 }
175 
176 /**
177  * Sets the number of allocations until we simulate a failed
178  * allocation. If set to 0, the next allocation to run
179  * fails; if set to 1, one succeeds then the next fails; etc.
180  * Set to _DBUS_INT_MAX to not fail anything.
181  *
182  * @param until_next_fail number of successful allocs before one fails
183  */
184 void
_dbus_set_fail_alloc_counter(int until_next_fail)185 _dbus_set_fail_alloc_counter (int until_next_fail)
186 {
187   _dbus_initialize_malloc_debug ();
188 
189   fail_alloc_counter = until_next_fail;
190 
191 #if 0
192   _dbus_verbose ("Set fail alloc counter = %d\n", fail_alloc_counter);
193 #endif
194 }
195 
196 /**
197  * Gets the number of successful allocs until we'll simulate
198  * a failed alloc.
199  *
200  * @returns current counter value
201  */
202 int
_dbus_get_fail_alloc_counter(void)203 _dbus_get_fail_alloc_counter (void)
204 {
205   _dbus_initialize_malloc_debug ();
206 
207   return fail_alloc_counter;
208 }
209 
210 /**
211  * Sets how many mallocs to fail when the fail alloc counter reaches
212  * 0.
213  *
214  * @param failures_per_failure number to fail
215  */
216 void
_dbus_set_fail_alloc_failures(int failures_per_failure)217 _dbus_set_fail_alloc_failures (int failures_per_failure)
218 {
219   n_failures_per_failure = failures_per_failure;
220 }
221 
222 /**
223  * Gets the number of failures we'll have when the fail malloc
224  * counter reaches 0.
225  *
226  * @returns number of failures planned
227  */
228 int
_dbus_get_fail_alloc_failures(void)229 _dbus_get_fail_alloc_failures (void)
230 {
231   return n_failures_per_failure;
232 }
233 
234 #ifdef DBUS_BUILD_TESTS
235 /**
236  * Called when about to alloc some memory; if
237  * it returns #TRUE, then the allocation should
238  * fail. If it returns #FALSE, then the allocation
239  * should not fail.
240  *
241  * @returns #TRUE if this alloc should fail
242  */
243 dbus_bool_t
_dbus_decrement_fail_alloc_counter(void)244 _dbus_decrement_fail_alloc_counter (void)
245 {
246   _dbus_initialize_malloc_debug ();
247 
248   if (fail_alloc_counter <= 0)
249     {
250       if (backtrace_on_fail_alloc)
251         _dbus_print_backtrace ();
252 
253       _dbus_verbose ("failure %d\n", n_failures_this_failure);
254 
255       n_failures_this_failure += 1;
256       if (n_failures_this_failure >= n_failures_per_failure)
257         {
258           if (fail_nth >= 0)
259             fail_alloc_counter = fail_nth;
260           else
261             fail_alloc_counter = _DBUS_INT_MAX;
262 
263           n_failures_this_failure = 0;
264 
265           _dbus_verbose ("reset fail alloc counter to %d\n", fail_alloc_counter);
266         }
267 
268       return TRUE;
269     }
270   else
271     {
272       fail_alloc_counter -= 1;
273       return FALSE;
274     }
275 }
276 #endif /* DBUS_BUILD_TESTS */
277 
278 /**
279  * Get the number of outstanding malloc()'d blocks.
280  *
281  * @returns number of blocks
282  */
283 int
_dbus_get_malloc_blocks_outstanding(void)284 _dbus_get_malloc_blocks_outstanding (void)
285 {
286   return n_blocks_outstanding.value;
287 }
288 
289 /**
290  * Where the block came from.
291  */
292 typedef enum
293 {
294   SOURCE_UNKNOWN,
295   SOURCE_MALLOC,
296   SOURCE_REALLOC,
297   SOURCE_MALLOC_ZERO,
298   SOURCE_REALLOC_NULL
299 } BlockSource;
300 
301 static const char*
source_string(BlockSource source)302 source_string (BlockSource source)
303 {
304   switch (source)
305     {
306     case SOURCE_UNKNOWN:
307       return "unknown";
308     case SOURCE_MALLOC:
309       return "malloc";
310     case SOURCE_REALLOC:
311       return "realloc";
312     case SOURCE_MALLOC_ZERO:
313       return "malloc0";
314     case SOURCE_REALLOC_NULL:
315       return "realloc(NULL)";
316     }
317   _dbus_assert_not_reached ("Invalid malloc block source ID");
318   return "invalid!";
319 }
320 
321 static void
check_guards(void * free_block,dbus_bool_t overwrite)322 check_guards (void       *free_block,
323               dbus_bool_t overwrite)
324 {
325   if (free_block != NULL)
326     {
327       unsigned char *block = ((unsigned char*)free_block) - GUARD_START_OFFSET;
328       size_t requested_bytes = *(dbus_uint32_t*)block;
329       BlockSource source = *(dbus_uint32_t*)(block + 4);
330       unsigned int i;
331       dbus_bool_t failed;
332 
333       failed = FALSE;
334 
335 #if 0
336       _dbus_verbose ("Checking %d bytes request from source %s\n",
337                      requested_bytes, source_string (source));
338 #endif
339 
340       i = GUARD_INFO_SIZE;
341       while (i < GUARD_START_OFFSET)
342         {
343           dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
344           if (value != GUARD_VALUE)
345             {
346               _dbus_warn ("Block of %lu bytes from %s had start guard value 0x%ux at %d expected 0x%x\n",
347                           (long) requested_bytes, source_string (source),
348                           value, i, GUARD_VALUE);
349               failed = TRUE;
350             }
351 
352           i += 4;
353         }
354 
355       i = GUARD_START_OFFSET + requested_bytes;
356       while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
357         {
358           dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
359           if (value != GUARD_VALUE)
360             {
361               _dbus_warn ("Block of %lu bytes from %s had end guard value 0x%ux at %d expected 0x%x\n",
362                           (long) requested_bytes, source_string (source),
363                           value, i, GUARD_VALUE);
364               failed = TRUE;
365             }
366 
367           i += 4;
368         }
369 
370       /* set memory to anything but nul bytes */
371       if (overwrite)
372         memset (free_block, 'g', requested_bytes);
373 
374       if (failed)
375         _dbus_assert_not_reached ("guard value corruption");
376     }
377 }
378 
379 static void*
set_guards(void * real_block,size_t requested_bytes,BlockSource source)380 set_guards (void       *real_block,
381             size_t      requested_bytes,
382             BlockSource source)
383 {
384   unsigned char *block = real_block;
385   unsigned int i;
386 
387   if (block == NULL)
388     return NULL;
389 
390   _dbus_assert (GUARD_START_OFFSET + GUARD_END_PAD == GUARD_EXTRA_SIZE);
391 
392   *((dbus_uint32_t*)block) = requested_bytes;
393   *((dbus_uint32_t*)(block + 4)) = source;
394 
395   i = GUARD_INFO_SIZE;
396   while (i < GUARD_START_OFFSET)
397     {
398       (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
399 
400       i += 4;
401     }
402 
403   i = GUARD_START_OFFSET + requested_bytes;
404   while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
405     {
406       (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
407 
408       i += 4;
409     }
410 
411   check_guards (block + GUARD_START_OFFSET, FALSE);
412 
413   return block + GUARD_START_OFFSET;
414 }
415 
416 #endif
417 
418 /** @} */ /* End of internals docs */
419 
420 
421 /**
422  * @addtogroup DBusMemory
423  *
424  * @{
425  */
426 
427 /**
428  * Allocates the given number of bytes, as with standard
429  * malloc(). Guaranteed to return #NULL if bytes is zero
430  * on all platforms. Returns #NULL if the allocation fails.
431  * The memory must be released with dbus_free().
432  *
433  * dbus_malloc() memory is NOT safe to free with regular free() from
434  * the C library. Free it with dbus_free() only.
435  *
436  * @param bytes number of bytes to allocate
437  * @return allocated memory, or #NULL if the allocation fails.
438  */
439 void*
dbus_malloc(size_t bytes)440 dbus_malloc (size_t bytes)
441 {
442 #ifdef DBUS_BUILD_TESTS
443   _dbus_initialize_malloc_debug ();
444 
445   if (_dbus_decrement_fail_alloc_counter ())
446     {
447       _dbus_verbose (" FAILING malloc of %ld bytes\n", (long) bytes);
448       return NULL;
449     }
450 #endif
451 
452   if (bytes == 0) /* some system mallocs handle this, some don't */
453     return NULL;
454 #ifdef DBUS_BUILD_TESTS
455   else if (fail_size != 0 && bytes > fail_size)
456     return NULL;
457   else if (guards)
458     {
459       void *block;
460 
461       block = malloc (bytes + GUARD_EXTRA_SIZE);
462       if (block)
463 	_dbus_atomic_inc (&n_blocks_outstanding);
464 
465       return set_guards (block, bytes, SOURCE_MALLOC);
466     }
467 #endif
468   else
469     {
470       void *mem;
471       mem = malloc (bytes);
472 #ifdef DBUS_BUILD_TESTS
473       if (mem)
474 	_dbus_atomic_inc (&n_blocks_outstanding);
475 #endif
476       return mem;
477     }
478 }
479 
480 /**
481  * Allocates the given number of bytes, as with standard malloc(), but
482  * all bytes are initialized to zero as with calloc(). Guaranteed to
483  * return #NULL if bytes is zero on all platforms. Returns #NULL if the
484  * allocation fails.  The memory must be released with dbus_free().
485  *
486  * dbus_malloc0() memory is NOT safe to free with regular free() from
487  * the C library. Free it with dbus_free() only.
488  *
489  * @param bytes number of bytes to allocate
490  * @return allocated memory, or #NULL if the allocation fails.
491  */
492 void*
dbus_malloc0(size_t bytes)493 dbus_malloc0 (size_t bytes)
494 {
495 #ifdef DBUS_BUILD_TESTS
496   _dbus_initialize_malloc_debug ();
497 
498   if (_dbus_decrement_fail_alloc_counter ())
499     {
500       _dbus_verbose (" FAILING malloc0 of %ld bytes\n", (long) bytes);
501 
502       return NULL;
503     }
504 #endif
505 
506   if (bytes == 0)
507     return NULL;
508 #ifdef DBUS_BUILD_TESTS
509   else if (fail_size != 0 && bytes > fail_size)
510     return NULL;
511   else if (guards)
512     {
513       void *block;
514 
515       block = calloc (bytes + GUARD_EXTRA_SIZE, 1);
516       if (block)
517 	_dbus_atomic_inc (&n_blocks_outstanding);
518       return set_guards (block, bytes, SOURCE_MALLOC_ZERO);
519     }
520 #endif
521   else
522     {
523       void *mem;
524       mem = calloc (bytes, 1);
525 #ifdef DBUS_BUILD_TESTS
526       if (mem)
527 	_dbus_atomic_inc (&n_blocks_outstanding);
528 #endif
529       return mem;
530     }
531 }
532 
533 /**
534  * Resizes a block of memory previously allocated by dbus_malloc() or
535  * dbus_malloc0(). Guaranteed to free the memory and return #NULL if bytes
536  * is zero on all platforms. Returns #NULL if the resize fails.
537  * If the resize fails, the memory is not freed.
538  *
539  * @param memory block to be resized
540  * @param bytes new size of the memory block
541  * @return allocated memory, or #NULL if the resize fails.
542  */
543 void*
dbus_realloc(void * memory,size_t bytes)544 dbus_realloc (void  *memory,
545               size_t bytes)
546 {
547 #ifdef DBUS_BUILD_TESTS
548   _dbus_initialize_malloc_debug ();
549 
550   if (_dbus_decrement_fail_alloc_counter ())
551     {
552       _dbus_verbose (" FAILING realloc of %ld bytes\n", (long) bytes);
553 
554       return NULL;
555     }
556 #endif
557 
558   if (bytes == 0) /* guarantee this is safe */
559     {
560       dbus_free (memory);
561       return NULL;
562     }
563 #ifdef DBUS_BUILD_TESTS
564   else if (fail_size != 0 && bytes > fail_size)
565     return NULL;
566   else if (guards)
567     {
568       if (memory)
569         {
570           size_t old_bytes;
571           void *block;
572 
573           check_guards (memory, FALSE);
574 
575           block = realloc (((unsigned char*)memory) - GUARD_START_OFFSET,
576                            bytes + GUARD_EXTRA_SIZE);
577 
578 	  old_bytes = *(dbus_uint32_t*)block;
579           if (block && bytes >= old_bytes)
580             /* old guards shouldn't have moved */
581             check_guards (((unsigned char*)block) + GUARD_START_OFFSET, FALSE);
582 
583           return set_guards (block, bytes, SOURCE_REALLOC);
584         }
585       else
586         {
587           void *block;
588 
589           block = malloc (bytes + GUARD_EXTRA_SIZE);
590 
591           if (block)
592 	    _dbus_atomic_inc (&n_blocks_outstanding);
593 
594           return set_guards (block, bytes, SOURCE_REALLOC_NULL);
595         }
596     }
597 #endif
598   else
599     {
600       void *mem;
601       mem = realloc (memory, bytes);
602 #ifdef DBUS_BUILD_TESTS
603       if (memory == NULL && mem != NULL)
604 	    _dbus_atomic_inc (&n_blocks_outstanding);
605 #endif
606       return mem;
607     }
608 }
609 
610 /**
611  * Frees a block of memory previously allocated by dbus_malloc() or
612  * dbus_malloc0(). If passed #NULL, does nothing.
613  *
614  * @param memory block to be freed
615  */
616 void
dbus_free(void * memory)617 dbus_free (void  *memory)
618 {
619 #ifdef DBUS_BUILD_TESTS
620   if (guards)
621     {
622       check_guards (memory, TRUE);
623       if (memory)
624         {
625 	  _dbus_atomic_dec (&n_blocks_outstanding);
626 
627 	  _dbus_assert (n_blocks_outstanding.value >= 0);
628 
629           free (((unsigned char*)memory) - GUARD_START_OFFSET);
630         }
631 
632       return;
633     }
634 #endif
635 
636   if (memory) /* we guarantee it's safe to free (NULL) */
637     {
638 #ifdef DBUS_BUILD_TESTS
639       _dbus_atomic_dec (&n_blocks_outstanding);
640 
641       _dbus_assert (n_blocks_outstanding.value >= 0);
642 #endif
643 
644       free (memory);
645     }
646 }
647 
648 /**
649  * Frees a #NULL-terminated array of strings.
650  * If passed #NULL, does nothing.
651  *
652  * @param str_array the array to be freed
653  */
654 void
dbus_free_string_array(char ** str_array)655 dbus_free_string_array (char **str_array)
656 {
657   if (str_array)
658     {
659       int i;
660 
661       i = 0;
662       while (str_array[i])
663 	{
664 	  dbus_free (str_array[i]);
665 	  i++;
666 	}
667 
668       dbus_free (str_array);
669     }
670 }
671 
672 /** @} */ /* End of public API docs block */
673 
674 
675 /**
676  * @addtogroup DBusMemoryInternals
677  *
678  * @{
679  */
680 
681 /**
682  * _dbus_current_generation is used to track each
683  * time that dbus_shutdown() is called, so we can
684  * reinit things after it's been called. It is simply
685  * incremented each time we shut down.
686  */
687 int _dbus_current_generation = 1;
688 
689 /**
690  * Represents a function to be called on shutdown.
691  */
692 typedef struct ShutdownClosure ShutdownClosure;
693 
694 /**
695  * This struct represents a function to be called on shutdown.
696  */
697 struct ShutdownClosure
698 {
699   ShutdownClosure *next;     /**< Next ShutdownClosure */
700   DBusShutdownFunction func; /**< Function to call */
701   void *data;                /**< Data for function */
702 };
703 
704 _DBUS_DEFINE_GLOBAL_LOCK (shutdown_funcs);
705 static ShutdownClosure *registered_globals = NULL;
706 
707 /**
708  * Register a cleanup function to be called exactly once
709  * the next time dbus_shutdown() is called.
710  *
711  * @param func the function
712  * @param data data to pass to the function
713  * @returns #FALSE on not enough memory
714  */
715 dbus_bool_t
_dbus_register_shutdown_func(DBusShutdownFunction func,void * data)716 _dbus_register_shutdown_func (DBusShutdownFunction  func,
717                               void                 *data)
718 {
719   ShutdownClosure *c;
720 
721   c = dbus_new (ShutdownClosure, 1);
722 
723   if (c == NULL)
724     return FALSE;
725 
726   c->func = func;
727   c->data = data;
728 
729   _DBUS_LOCK (shutdown_funcs);
730 
731   c->next = registered_globals;
732   registered_globals = c;
733 
734   _DBUS_UNLOCK (shutdown_funcs);
735 
736   return TRUE;
737 }
738 
739 /** @} */ /* End of private API docs block */
740 
741 
742 /**
743  * @addtogroup DBusMemory
744  *
745  * @{
746  */
747 
748 /**
749  * Frees all memory allocated internally by libdbus and
750  * reverses the effects of dbus_threads_init(). libdbus keeps internal
751  * global variables, for example caches and thread locks, and it
752  * can be useful to free these internal data structures.
753  *
754  * dbus_shutdown() does NOT free memory that was returned
755  * to the application. It only returns libdbus-internal
756  * data structures.
757  *
758  * You MUST free all memory and release all reference counts
759  * returned to you by libdbus prior to calling dbus_shutdown().
760  *
761  * You can't continue to use any D-Bus objects, such as connections,
762  * that were allocated prior to dbus_shutdown(). You can, however,
763  * start over; call dbus_threads_init() again, create new connections,
764  * and so forth.
765  *
766  * WARNING: dbus_shutdown() is NOT thread safe, it must be called
767  * while NO other threads are using D-Bus. (Remember, you have to free
768  * all D-Bus objects and memory before you call dbus_shutdown(), so no
769  * thread can be using libdbus.)
770  *
771  * The purpose of dbus_shutdown() is to allow applications to get
772  * clean output from memory leak checkers. dbus_shutdown() may also be
773  * useful if you want to dlopen() libdbus instead of linking to it,
774  * and want to be able to unload the library again.
775  *
776  * There is absolutely no requirement to call dbus_shutdown() - in fact,
777  * most applications won't bother and should not feel guilty.
778  *
779  * You have to know that nobody is using libdbus in your application's
780  * process before you can call dbus_shutdown(). One implication of this
781  * is that calling dbus_shutdown() from a library is almost certainly
782  * wrong, since you don't know what the rest of the app is up to.
783  *
784  */
785 void
dbus_shutdown(void)786 dbus_shutdown (void)
787 {
788   while (registered_globals != NULL)
789     {
790       ShutdownClosure *c;
791 
792       c = registered_globals;
793       registered_globals = c->next;
794 
795       (* c->func) (c->data);
796 
797       dbus_free (c);
798     }
799 
800   _dbus_current_generation += 1;
801 }
802 
803 /** @} */ /** End of public API docs block */
804 
805 #ifdef DBUS_BUILD_TESTS
806 #include "dbus-test.h"
807 
808 /**
809  * @ingroup DBusMemoryInternals
810  * Unit test for DBusMemory
811  * @returns #TRUE on success.
812  */
813 dbus_bool_t
_dbus_memory_test(void)814 _dbus_memory_test (void)
815 {
816   dbus_bool_t old_guards;
817   void *p;
818   size_t size;
819 
820   old_guards = guards;
821   guards = TRUE;
822   p = dbus_malloc (4);
823   if (p == NULL)
824     _dbus_assert_not_reached ("no memory");
825   for (size = 4; size < 256; size += 4)
826     {
827       p = dbus_realloc (p, size);
828       if (p == NULL)
829 	_dbus_assert_not_reached ("no memory");
830     }
831   for (size = 256; size != 0; size -= 4)
832     {
833       p = dbus_realloc (p, size);
834       if (p == NULL)
835 	_dbus_assert_not_reached ("no memory");
836     }
837   dbus_free (p);
838   guards = old_guards;
839   return TRUE;
840 }
841 
842 #endif
843