D-Bus 1.12.20
dbus-memory.c
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 /* end of public API docs */
93
100#ifdef DBUS_ENABLE_EMBEDDED_TESTS
101static dbus_bool_t debug_initialized = FALSE;
102static int fail_nth = -1;
103static size_t fail_size = 0;
104static int fail_alloc_counter = _DBUS_INT_MAX;
105static int n_failures_per_failure = 1;
106static int n_failures_this_failure = 0;
107static dbus_bool_t guards = FALSE;
108static dbus_bool_t disable_mem_pools = FALSE;
109static dbus_bool_t backtrace_on_fail_alloc = FALSE;
110static dbus_bool_t malloc_cannot_fail = FALSE;
111static DBusAtomic n_blocks_outstanding = {0};
112
114#define GUARD_VALUE 0xdeadbeef
116#define GUARD_INFO_SIZE 8
118#define GUARD_START_PAD 16
120#define GUARD_END_PAD 16
122#define GUARD_START_OFFSET (GUARD_START_PAD + GUARD_INFO_SIZE)
124#define GUARD_EXTRA_SIZE (GUARD_START_OFFSET + GUARD_END_PAD)
125
126static 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
179_dbus_disable_mem_pools (void)
180{
181 _dbus_initialize_malloc_debug ();
182 return disable_mem_pools;
183}
184
193void
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
211int
212_dbus_get_fail_alloc_counter (void)
213{
214 _dbus_initialize_malloc_debug ();
215
216 return fail_alloc_counter;
217}
218
225void
226_dbus_set_fail_alloc_failures (int failures_per_failure)
227{
228 n_failures_per_failure = failures_per_failure;
229}
230
237int
238_dbus_get_fail_alloc_failures (void)
239{
240 return n_failures_per_failure;
241}
242
243#ifdef DBUS_ENABLE_EMBEDDED_TESTS
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)
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
304int
305_dbus_get_malloc_blocks_outstanding (void)
306{
307 return _dbus_atomic_get (&n_blocks_outstanding);
308}
309
313typedef enum
314{
315 SOURCE_UNKNOWN,
316 SOURCE_MALLOC,
317 SOURCE_REALLOC,
318 SOURCE_MALLOC_ZERO,
319 SOURCE_REALLOC_NULL
320} BlockSource;
321
322static const char*
323source_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
343static void
344check_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
401static void*
402set_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 /* End of internals docs */
441
442
461void*
462dbus_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
531void*
532dbus_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
601void*
602dbus_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
701void
702dbus_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
749void
750dbus_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 /* End of public API docs block */
768
769
783
788
793{
795 DBusShutdownFunction func;
796 void *data;
797};
798
799/* Protected by _DBUS_LOCK (shutdown_funcs) */
800static ShutdownClosure *registered_globals = NULL;
801
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
825_dbus_register_shutdown_func_unlocked (DBusShutdownFunction func,
826 void *data)
827{
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 /* End of private API docs block */
845
846
897void
899{
900 while (registered_globals != NULL)
901 {
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. */
919}
920
923#ifdef DBUS_ENABLE_EMBEDDED_TESTS
924#include "dbus-test.h"
925
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
#define _dbus_assert_not_reached(explanation)
Aborts with an error message if called.
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
#define _DBUS_UNLOCK(name)
Unlocks a global lock.
#define _DBUS_LOCK(name)
Locks a global lock, initializing it first if necessary.
#define _DBUS_INT_MAX
Maximum value of type "int".
void _dbus_warn(const char *format,...)
Prints a warning message to stderr.
#define NULL
A null pointer, defined appropriately for C or C++.
#define TRUE
Expands to "1".
#define FALSE
Expands to "0".
int _dbus_current_generation
_dbus_current_generation is used to track each time that dbus_shutdown() is called,...
Definition: dbus-memory.c:782
dbus_bool_t _dbus_register_shutdown_func(DBusShutdownFunction func, void *data)
Register a cleanup function to be called exactly once the next time dbus_shutdown() is called.
Definition: dbus-memory.c:811
void dbus_shutdown(void)
Frees all memory allocated internally by libdbus and reverses the effects of dbus_threads_init().
Definition: dbus-memory.c:898
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:702
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:602
#define dbus_new(type, count)
Safe macro for using dbus_malloc().
Definition: dbus-memory.h:57
void * dbus_malloc0(size_t bytes)
Allocates the given number of bytes, as with standard malloc(), but all bytes are initialized to zero...
Definition: dbus-memory.c:532
void dbus_free_string_array(char **str_array)
Frees a NULL-terminated array of strings.
Definition: dbus-memory.c:750
void * dbus_malloc(size_t bytes)
Allocates the given number of bytes, as with standard malloc().
Definition: dbus-memory.c:462
dbus_int32_t _dbus_atomic_dec(DBusAtomic *atomic)
Atomically decrement an integer.
const char * _dbus_getenv(const char *varname)
Wrapper for getenv().
Definition: dbus-sysdeps.c:187
dbus_int32_t _dbus_atomic_get(DBusAtomic *atomic)
Atomically get the value of an integer.
void _dbus_threads_lock_platform_specific(void)
Lock a static mutex used to protect _dbus_threads_init_platform_specific().
void _dbus_threads_unlock_platform_specific(void)
Undo _dbus_threads_lock_platform_specific().
dbus_int32_t _dbus_atomic_inc(DBusAtomic *atomic)
Atomically increments an integer.
void _dbus_abort(void)
Aborts the program with SIGABRT (dumping core).
Definition: dbus-sysdeps.c:79
void _dbus_print_backtrace(void)
On GNU libc systems, print a crude backtrace to stderr.
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
int dbus_int32_t
A 32-bit signed integer on all platforms.
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:307
This struct represents a function to be called on shutdown.
Definition: dbus-memory.c:793
ShutdownClosure * next
Next ShutdownClosure.
Definition: dbus-memory.c:794
DBusShutdownFunction func
Function to call.
Definition: dbus-memory.c:795
void * data
Data for function.
Definition: dbus-memory.c:796