libbacktrace/instrumented_alloc.c

   1 /* instrumented_alloc.c -- Memory allocation instrumented to fail when
   2    requested, for testing purposes.
   3    Copyright (C) 2018-2020 Free Software Foundation, Inc.
   4
   5 Redistribution and use in source and binary forms, with or without
   6 modification, are permitted provided that the following conditions are
   7 met:
   8
   9     (1) Redistributions of source code must retain the above copyright
  10     notice, this list of conditions and the following disclaimer.
  11
  12     (2) Redistributions in binary form must reproduce the above copyright
  13     notice, this list of conditions and the following disclaimer in
  14     the documentation and/or other materials provided with the
  15     distribution.
  16
  17     (3) The name of the author may not be used to
  18     endorse or promote products derived from this software without
  19     specific prior written permission.
  20
  21 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  25 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  26 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  27 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  29 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30 IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31 POSSIBILITY OF SUCH DAMAGE.  */
  32
  33 /* Include all the header files of alloc here, to make sure they're not
  34    processed when including alloc.c below, such that the redefinitions of malloc
  35    and realloc are only effective in alloc.c itself.  This does not work for
  36    config.h, because it's not wrapped in "#ifndef CONFIG_H\n#define CONFIG_H"
  37    and "#endif" but that does not seem to be harmful.  */
  38
  39 #include "config.h"
  40
  41 #include <errno.h>
  42 #include <stdlib.h>
  43 #include <sys/types.h>
  44 #include <inttypes.h>
  45
  46 #include "backtrace.h"
  47 #include "internal.h"
  48
  49 extern void *instrumented_malloc (size_t size);
  50 extern void *instrumented_realloc (void *ptr, size_t size);
  51
  52 #define malloc instrumented_malloc
  53 #define realloc instrumented_realloc
  54 #include "alloc.c"
  55 #undef malloc
  56 #undef realloc
  57
  58 static uint64_t nr_allocs = 0;
  59 static uint64_t fail_at_alloc = 0;
  60
  61 extern int at_fail_alloc_p (void);
  62 extern uint64_t get_nr_allocs (void);
  63 extern void set_fail_at_alloc (uint64_t);
  64
  65 void *
  66 instrumented_malloc (size_t size)
  67 {
  68   void *res;
  69
  70   if (at_fail_alloc_p ())
  71     return NULL;
  72
  73   res = malloc (size);
  74   if (res != NULL)
  75     nr_allocs++;
  76
  77   return res;
  78 }
  79
  80 void *
  81 instrumented_realloc (void *ptr, size_t size)
  82 {
  83   void *res;
  84
  85   if (size != 0)
  86     {
  87       if (at_fail_alloc_p ())
  88         return NULL;
  89     }
  90
  91   res = realloc (ptr, size);
  92   if (res != NULL)
  93     nr_allocs++;
  94
  95   return res;
  96 }
  97
  98 int
  99 at_fail_alloc_p (void)
 100 {
 101   return fail_at_alloc == nr_allocs + 1;
 102 }
 103
 104 uint64_t
 105 get_nr_allocs (void)
 106 {
 107   return nr_allocs;
 108 }
 109
 110 void
 111 set_fail_at_alloc (uint64_t nr)
 112 {
 113   fail_at_alloc = nr;
 114 }