D-Bus  1.14.10
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 <dbus/dbus-test-tap.h>
31 #include <stdlib.h>
32  /* end of public API docs */
94 
101 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
102 /* Test-only, does not need to be thread-safe */
103 static dbus_bool_t debug_initialized = FALSE;
104 static int fail_nth = -1;
105 static size_t fail_size = 0;
106 static int fail_alloc_counter = _DBUS_INT_MAX;
107 static int n_failures_per_failure = 1;
108 static int n_failures_this_failure = 0;
109 static dbus_bool_t guards = FALSE;
110 static dbus_bool_t disable_mem_pools = FALSE;
111 static dbus_bool_t backtrace_on_fail_alloc = FALSE;
112 static dbus_bool_t malloc_cannot_fail = FALSE;
113 static DBusAtomic n_blocks_outstanding = {0};
114 
116 #define GUARD_VALUE 0xdeadbeef
118 #define GUARD_INFO_SIZE 8
120 #define GUARD_START_PAD 16
122 #define GUARD_END_PAD 16
124 #define GUARD_START_OFFSET (GUARD_START_PAD + GUARD_INFO_SIZE)
126 #define GUARD_EXTRA_SIZE (GUARD_START_OFFSET + GUARD_END_PAD)
127 
128 static void
129 _dbus_initialize_malloc_debug (void)
130 {
131  if (!debug_initialized)
132  {
133  debug_initialized = TRUE;
134 
135  if (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH") != NULL)
136  {
137  fail_nth = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_NTH"));
138  fail_alloc_counter = fail_nth;
139  _dbus_verbose ("Will fail dbus_malloc every %d times\n", fail_nth);
140  }
141 
142  if (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN") != NULL)
143  {
144  fail_size = atoi (_dbus_getenv ("DBUS_MALLOC_FAIL_GREATER_THAN"));
145  _dbus_verbose ("Will fail mallocs over %ld bytes\n",
146  (long) fail_size);
147  }
148 
149  if (_dbus_getenv ("DBUS_MALLOC_GUARDS") != NULL)
150  {
151  guards = TRUE;
152  _dbus_verbose ("Will use dbus_malloc guards\n");
153  }
154 
155  if (_dbus_getenv ("DBUS_DISABLE_MEM_POOLS") != NULL)
156  {
157  disable_mem_pools = TRUE;
158  _dbus_verbose ("Will disable memory pools\n");
159  }
160 
161  if (_dbus_getenv ("DBUS_MALLOC_BACKTRACES") != NULL)
162  {
163  backtrace_on_fail_alloc = TRUE;
164  _dbus_verbose ("Will backtrace on failing a dbus_malloc\n");
165  }
166 
167  if (_dbus_getenv ("DBUS_MALLOC_CANNOT_FAIL") != NULL)
168  {
169  malloc_cannot_fail = TRUE;
170  _dbus_verbose ("Will abort if system malloc() and friends fail\n");
171  }
172  }
173 }
174 
181 _dbus_disable_mem_pools (void)
182 {
183  _dbus_initialize_malloc_debug ();
184  return disable_mem_pools;
185 }
186 
195 void
196 _dbus_set_fail_alloc_counter (int until_next_fail)
197 {
198  _dbus_initialize_malloc_debug ();
199 
200  fail_alloc_counter = until_next_fail;
201 
202 #if 0
203  _dbus_verbose ("Set fail alloc counter = %d\n", fail_alloc_counter);
204 #endif
205 }
206 
213 int
214 _dbus_get_fail_alloc_counter (void)
215 {
216  _dbus_initialize_malloc_debug ();
217 
218  return fail_alloc_counter;
219 }
220 
227 void
228 _dbus_set_fail_alloc_failures (int failures_per_failure)
229 {
230  n_failures_per_failure = failures_per_failure;
231 }
232 
239 int
240 _dbus_get_fail_alloc_failures (void)
241 {
242  return n_failures_per_failure;
243 }
244 
245 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
255 _dbus_decrement_fail_alloc_counter (void)
256 {
257  _dbus_initialize_malloc_debug ();
258 
259  if (fail_alloc_counter <= 0)
260  {
261  if (backtrace_on_fail_alloc)
263 
264  _dbus_verbose ("failure %d\n", n_failures_this_failure);
265 
266  n_failures_this_failure += 1;
267  if (n_failures_this_failure >= n_failures_per_failure)
268  {
269  if (fail_nth >= 0)
270  fail_alloc_counter = fail_nth;
271  else
272  fail_alloc_counter = _DBUS_INT_MAX;
273 
274  n_failures_this_failure = 0;
275 
276  _dbus_verbose ("reset fail alloc counter to %d\n", fail_alloc_counter);
277  }
278 
279  return TRUE;
280  }
281  else
282  {
283  fail_alloc_counter -= 1;
284  return FALSE;
285  }
286 }
287 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
288 
294 int
295 _dbus_get_malloc_blocks_outstanding (void)
296 {
297  return _dbus_atomic_get (&n_blocks_outstanding);
298 }
299 
303 typedef enum
304 {
305  SOURCE_UNKNOWN,
306  SOURCE_MALLOC,
307  SOURCE_REALLOC,
308  SOURCE_MALLOC_ZERO,
309  SOURCE_REALLOC_NULL
310 } BlockSource;
311 
312 static const char*
313 source_string (BlockSource source)
314 {
315  switch (source)
316  {
317  case SOURCE_UNKNOWN:
318  return "unknown";
319  case SOURCE_MALLOC:
320  return "malloc";
321  case SOURCE_REALLOC:
322  return "realloc";
323  case SOURCE_MALLOC_ZERO:
324  return "malloc0";
325  case SOURCE_REALLOC_NULL:
326  return "realloc(NULL)";
327  default:
328  _dbus_assert_not_reached ("Invalid malloc block source ID");
329  return "invalid!";
330  }
331 }
332 
333 static void
334 check_guards (void *free_block,
335  dbus_bool_t overwrite)
336 {
337  if (free_block != NULL)
338  {
339  unsigned char *block = ((unsigned char*)free_block) - GUARD_START_OFFSET;
340  size_t requested_bytes = *(dbus_uint32_t*)block;
341  BlockSource source = *(dbus_uint32_t*)(block + 4);
342  unsigned int i;
343  dbus_bool_t failed;
344 
345  failed = FALSE;
346 
347 #if 0
348  _dbus_verbose ("Checking %d bytes request from source %s\n",
349  requested_bytes, source_string (source));
350 #endif
351 
352  i = GUARD_INFO_SIZE;
353  while (i < GUARD_START_OFFSET)
354  {
355  dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
356  if (value != GUARD_VALUE)
357  {
358  _dbus_warn ("Block of %lu bytes from %s had start guard value 0x%ux at %d expected 0x%x",
359  (long) requested_bytes, source_string (source),
360  value, i, GUARD_VALUE);
361  failed = TRUE;
362  }
363 
364  i += 4;
365  }
366 
367  i = GUARD_START_OFFSET + requested_bytes;
368  while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
369  {
370  dbus_uint32_t value = *(dbus_uint32_t*) &block[i];
371  if (value != GUARD_VALUE)
372  {
373  _dbus_warn ("Block of %lu bytes from %s had end guard value 0x%ux at %d expected 0x%x",
374  (long) requested_bytes, source_string (source),
375  value, i, GUARD_VALUE);
376  failed = TRUE;
377  }
378 
379  i += 4;
380  }
381 
382  /* set memory to anything but nul bytes */
383  if (overwrite)
384  memset (free_block, 'g', requested_bytes);
385 
386  if (failed)
387  _dbus_assert_not_reached ("guard value corruption");
388  }
389 }
390 
391 static void*
392 set_guards (void *real_block,
393  size_t requested_bytes,
394  BlockSource source)
395 {
396  unsigned char *block = real_block;
397  unsigned int i;
398 
399  if (block == NULL)
400  return NULL;
401 
402  _dbus_assert (GUARD_START_OFFSET + GUARD_END_PAD == GUARD_EXTRA_SIZE);
403 
404  *((dbus_uint32_t*)block) = requested_bytes;
405  *((dbus_uint32_t*)(block + 4)) = source;
406 
407  i = GUARD_INFO_SIZE;
408  while (i < GUARD_START_OFFSET)
409  {
410  (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
411 
412  i += 4;
413  }
414 
415  i = GUARD_START_OFFSET + requested_bytes;
416  while (i < (GUARD_START_OFFSET + requested_bytes + GUARD_END_PAD))
417  {
418  (*(dbus_uint32_t*) &block[i]) = GUARD_VALUE;
419 
420  i += 4;
421  }
422 
423  check_guards (block + GUARD_START_OFFSET, FALSE);
424 
425  return block + GUARD_START_OFFSET;
426 }
427 
428 #endif
429  /* End of internals docs */
431 
432 
451 void*
452 dbus_malloc (size_t bytes)
453 {
454 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
455  _dbus_initialize_malloc_debug ();
456 
457  if (_dbus_decrement_fail_alloc_counter ())
458  {
459  _dbus_verbose (" FAILING malloc of %ld bytes\n", (long) bytes);
460  return NULL;
461  }
462 #endif
463 
464  if (bytes == 0) /* some system mallocs handle this, some don't */
465  return NULL;
466 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
467  else if (fail_size != 0 && bytes > fail_size)
468  return NULL;
469  else if (guards)
470  {
471  void *block;
472 
473  block = malloc (bytes + GUARD_EXTRA_SIZE);
474  if (block)
475  {
476  _dbus_atomic_inc (&n_blocks_outstanding);
477  }
478  else if (malloc_cannot_fail)
479  {
480  _dbus_warn ("out of memory: malloc (%ld + %ld)",
481  (long) bytes, (long) GUARD_EXTRA_SIZE);
482  _dbus_abort ();
483  }
484 
485  return set_guards (block, bytes, SOURCE_MALLOC);
486  }
487 #endif
488  else
489  {
490  void *mem;
491  mem = malloc (bytes);
492 
493 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
494  if (mem)
495  {
496  _dbus_atomic_inc (&n_blocks_outstanding);
497  }
498  else if (malloc_cannot_fail)
499  {
500  _dbus_warn ("out of memory: malloc (%ld)", (long) bytes);
501  _dbus_abort ();
502  }
503 #endif
504 
505  return mem;
506  }
507 }
508 
521 void*
522 dbus_malloc0 (size_t bytes)
523 {
524 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
525  _dbus_initialize_malloc_debug ();
526 
527  if (_dbus_decrement_fail_alloc_counter ())
528  {
529  _dbus_verbose (" FAILING malloc0 of %ld bytes\n", (long) bytes);
530 
531  return NULL;
532  }
533 #endif
534 
535  if (bytes == 0)
536  return NULL;
537 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
538  else if (fail_size != 0 && bytes > fail_size)
539  return NULL;
540  else if (guards)
541  {
542  void *block;
543 
544  block = calloc (bytes + GUARD_EXTRA_SIZE, 1);
545 
546  if (block)
547  {
548  _dbus_atomic_inc (&n_blocks_outstanding);
549  }
550  else if (malloc_cannot_fail)
551  {
552  _dbus_warn ("out of memory: calloc (%ld + %ld, 1)",
553  (long) bytes, (long) GUARD_EXTRA_SIZE);
554  _dbus_abort ();
555  }
556 
557  return set_guards (block, bytes, SOURCE_MALLOC_ZERO);
558  }
559 #endif
560  else
561  {
562  void *mem;
563  mem = calloc (bytes, 1);
564 
565 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
566  if (mem)
567  {
568  _dbus_atomic_inc (&n_blocks_outstanding);
569  }
570  else if (malloc_cannot_fail)
571  {
572  _dbus_warn ("out of memory: calloc (%ld)", (long) bytes);
573  _dbus_abort ();
574  }
575 #endif
576 
577  return mem;
578  }
579 }
580 
591 void*
592 dbus_realloc (void *memory,
593  size_t bytes)
594 {
595 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
596  _dbus_initialize_malloc_debug ();
597 
598  if (_dbus_decrement_fail_alloc_counter ())
599  {
600  _dbus_verbose (" FAILING realloc of %ld bytes\n", (long) bytes);
601 
602  return NULL;
603  }
604 #endif
605 
606  if (bytes == 0) /* guarantee this is safe */
607  {
608  dbus_free (memory);
609  return NULL;
610  }
611 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
612  else if (fail_size != 0 && bytes > fail_size)
613  return NULL;
614  else if (guards)
615  {
616  if (memory)
617  {
618  size_t old_bytes;
619  void *block;
620 
621  check_guards (memory, FALSE);
622 
623  block = realloc (((unsigned char*)memory) - GUARD_START_OFFSET,
624  bytes + GUARD_EXTRA_SIZE);
625 
626  if (block == NULL)
627  {
628  if (malloc_cannot_fail)
629  {
630  _dbus_warn ("out of memory: realloc (%p, %ld + %ld)",
631  memory, (long) bytes, (long) GUARD_EXTRA_SIZE);
632  _dbus_abort ();
633  }
634 
635  return NULL;
636  }
637 
638  old_bytes = *(dbus_uint32_t*)block;
639  if (bytes >= old_bytes)
640  /* old guards shouldn't have moved */
641  check_guards (((unsigned char*)block) + GUARD_START_OFFSET, FALSE);
642 
643  return set_guards (block, bytes, SOURCE_REALLOC);
644  }
645  else
646  {
647  void *block;
648 
649  block = malloc (bytes + GUARD_EXTRA_SIZE);
650 
651  if (block)
652  {
653  _dbus_atomic_inc (&n_blocks_outstanding);
654  }
655  else if (malloc_cannot_fail)
656  {
657  _dbus_warn ("out of memory: malloc (%ld + %ld)",
658  (long) bytes, (long) GUARD_EXTRA_SIZE);
659  _dbus_abort ();
660  }
661 
662  return set_guards (block, bytes, SOURCE_REALLOC_NULL);
663  }
664  }
665 #endif
666  else
667  {
668  void *mem;
669  mem = realloc (memory, bytes);
670 
671 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
672  if (mem == NULL && malloc_cannot_fail)
673  {
674  _dbus_warn ("out of memory: malloc (%ld)", (long) bytes);
675  _dbus_abort ();
676  }
677 
678  if (memory == NULL && mem != NULL)
679  _dbus_atomic_inc (&n_blocks_outstanding);
680 #endif
681  return mem;
682  }
683 }
684 
691 void
692 dbus_free (void *memory)
693 {
694 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
695  if (guards)
696  {
697  check_guards (memory, TRUE);
698  if (memory)
699  {
700 #ifdef DBUS_DISABLE_ASSERT
701  _dbus_atomic_dec (&n_blocks_outstanding);
702 #else
703  dbus_int32_t old_value;
704 
705  old_value = _dbus_atomic_dec (&n_blocks_outstanding);
706  _dbus_assert (old_value >= 1);
707 #endif
708 
709  free (((unsigned char*)memory) - GUARD_START_OFFSET);
710  }
711 
712  return;
713  }
714 #endif
715 
716  if (memory) /* we guarantee it's safe to free (NULL) */
717  {
718 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
719 #ifdef DBUS_DISABLE_ASSERT
720  _dbus_atomic_dec (&n_blocks_outstanding);
721 #else
722  dbus_int32_t old_value;
723 
724  old_value = _dbus_atomic_dec (&n_blocks_outstanding);
725  _dbus_assert (old_value >= 1);
726 #endif
727 #endif
728 
729  free (memory);
730  }
731 }
732 
739 void
740 dbus_free_string_array (char **str_array)
741 {
742  if (str_array)
743  {
744  int i;
745 
746  i = 0;
747  while (str_array[i])
748  {
749  dbus_free (str_array[i]);
750  i++;
751  }
752 
753  dbus_free (str_array);
754  }
755 }
756  /* End of public API docs block */
758 
759 
773 
777 typedef struct ShutdownClosure ShutdownClosure;
778 
783 {
785  DBusShutdownFunction func;
786  void *data;
787 };
788 
789 /* Protected by _DBUS_LOCK (shutdown_funcs) */
790 static ShutdownClosure *registered_globals = NULL;
791 
801 _dbus_register_shutdown_func (DBusShutdownFunction func,
802  void *data)
803 {
804  dbus_bool_t ok;
805 
806  if (!_DBUS_LOCK (shutdown_funcs))
807  return FALSE;
808 
809  ok = _dbus_register_shutdown_func_unlocked (func, data);
810  _DBUS_UNLOCK (shutdown_funcs);
811  return ok;
812 }
813 
815 _dbus_register_shutdown_func_unlocked (DBusShutdownFunction func,
816  void *data)
817 {
818  ShutdownClosure *c;
819 
820  c = dbus_new (ShutdownClosure, 1);
821 
822  if (c == NULL)
823  return FALSE;
824 
825  c->func = func;
826  c->data = data;
827 
828  c->next = registered_globals;
829  registered_globals = c;
830 
831  return TRUE;
832 }
833  /* End of private API docs block */
835 
836 
887 void
889 {
890  while (registered_globals != NULL)
891  {
892  ShutdownClosure *c;
893 
894  c = registered_globals;
895  registered_globals = c->next;
896 
897  (* c->func) (c->data);
898 
899  dbus_free (c);
900  }
901 
902  /* We wrap this in the thread-initialization lock because
903  * dbus_threads_init() uses the current generation to tell whether
904  * we're initialized, so we need to make sure that un-initializing
905  * propagates into all threads. */
909 }
910 
913 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
914 #include "dbus-test.h"
915 
922 _dbus_memory_test (const char *test_data_dir _DBUS_GNUC_UNUSED)
923 {
924  dbus_bool_t old_guards;
925  void *p;
926  size_t size;
927 
928  old_guards = guards;
929  guards = TRUE;
930  p = dbus_malloc (4);
931  if (p == NULL)
932  _dbus_test_fatal ("no memory");
933  for (size = 4; size < 256; size += 4)
934  {
935  p = dbus_realloc (p, size);
936  if (p == NULL)
937  _dbus_test_fatal ("no memory");
938  }
939  for (size = 256; size != 0; size -= 4)
940  {
941  p = dbus_realloc (p, size);
942  if (p == NULL)
943  _dbus_test_fatal ("no memory");
944  }
945  dbus_free (p);
946  guards = old_guards;
947  return TRUE;
948 }
949 
950 #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:772
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:801
void dbus_shutdown(void)
Frees all memory allocated internally by libdbus and reverses the effects of dbus_threads_init().
Definition: dbus-memory.c:888
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:692
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:592
#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:522
void dbus_free_string_array(char **str_array)
Frees a NULL-terminated array of strings.
Definition: dbus-memory.c:740
void * dbus_malloc(size_t bytes)
Allocates the given number of bytes, as with standard malloc().
Definition: dbus-memory.c:452
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:195
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:87
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
An atomic integer safe to increment or decrement from multiple threads.
Definition: dbus-sysdeps.h:324
This struct represents a function to be called on shutdown.
Definition: dbus-memory.c:783
ShutdownClosure * next
Next ShutdownClosure.
Definition: dbus-memory.c:784
DBusShutdownFunction func
Function to call.
Definition: dbus-memory.c:785
void * data
Data for function.
Definition: dbus-memory.c:786