1/* Debug allocators for the Expat test suite
2                            __  __            _
3                         ___\ \/ /_ __   __ _| |_
4                        / _ \\  /| '_ \ / _` | __|
5                       |  __//  \| |_) | (_| | |_
6                        \___/_/\_\ .__/ \__,_|\__|
7                                 |_| XML parser
8
9   Copyright (c) 1997-2000 Thai Open Source Software Center Ltd
10   Copyright (c) 2000-2017 Expat development team
11   Licensed under the MIT license:
12
13   Permission is  hereby granted,  free of charge,  to any  person obtaining
14   a  copy  of  this  software   and  associated  documentation  files  (the
15   "Software"),  to  deal in  the  Software  without restriction,  including
16   without  limitation the  rights  to use,  copy,  modify, merge,  publish,
17   distribute, sublicense, and/or sell copies of the Software, and to permit
18   persons  to whom  the Software  is  furnished to  do so,  subject to  the
19   following conditions:
20
21   The above copyright  notice and this permission notice  shall be included
22   in all copies or substantial portions of the Software.
23
24   THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
25   EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
26   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
27   NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
28   DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
29   OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
30   USE OR OTHER DEALINGS IN THE SOFTWARE.
31*/
32
33#include <stdio.h>
34#include <stdlib.h>
35#include "memcheck.h"
36
37/* Structures to keep track of what has been allocated.  Speed isn't a
38 * big issue for the tests this is required for, so we will use a
39 * doubly-linked list to make deletion easier.
40 */
41
42typedef struct allocation_entry {
43  struct allocation_entry *next;
44  struct allocation_entry *prev;
45  void *allocation;
46  size_t num_bytes;
47} AllocationEntry;
48
49static AllocationEntry *alloc_head = NULL;
50static AllocationEntry *alloc_tail = NULL;
51
52static AllocationEntry *find_allocation(void *ptr);
53
54/* Allocate some memory and keep track of it. */
55void *
56tracking_malloc(size_t size) {
57  AllocationEntry *entry = malloc(sizeof(AllocationEntry));
58
59  if (entry == NULL) {
60    printf("Allocator failure\n");
61    return NULL;
62  }
63  entry->num_bytes = size;
64  entry->allocation = malloc(size);
65  if (entry->allocation == NULL) {
66    free(entry);
67    return NULL;
68  }
69  entry->next = NULL;
70
71  /* Add to the list of allocations */
72  if (alloc_head == NULL) {
73    entry->prev = NULL;
74    alloc_head = alloc_tail = entry;
75  } else {
76    entry->prev = alloc_tail;
77    alloc_tail->next = entry;
78    alloc_tail = entry;
79  }
80
81  return entry->allocation;
82}
83
84static AllocationEntry *
85find_allocation(void *ptr) {
86  AllocationEntry *entry;
87
88  for (entry = alloc_head; entry != NULL; entry = entry->next) {
89    if (entry->allocation == ptr) {
90      return entry;
91    }
92  }
93  return NULL;
94}
95
96/* Free some memory and remove the tracking for it */
97void
98tracking_free(void *ptr) {
99  AllocationEntry *entry;
100
101  if (ptr == NULL) {
102    /* There won't be an entry for this */
103    return;
104  }
105
106  entry = find_allocation(ptr);
107  if (entry != NULL) {
108    /* This is the relevant allocation.  Unlink it */
109    if (entry->prev != NULL)
110      entry->prev->next = entry->next;
111    else
112      alloc_head = entry->next;
113    if (entry->next != NULL)
114      entry->next->prev = entry->prev;
115    else
116      alloc_tail = entry->next;
117    free(entry);
118  } else {
119    printf("Attempting to free unallocated memory at %p\n", ptr);
120  }
121  free(ptr);
122}
123
124/* Reallocate some memory and keep track of it */
125void *
126tracking_realloc(void *ptr, size_t size) {
127  AllocationEntry *entry;
128
129  if (ptr == NULL) {
130    /* By definition, this is equivalent to malloc(size) */
131    return tracking_malloc(size);
132  }
133  if (size == 0) {
134    /* By definition, this is equivalent to free(ptr) */
135    tracking_free(ptr);
136    return NULL;
137  }
138
139  /* Find the allocation entry for this memory */
140  entry = find_allocation(ptr);
141  if (entry == NULL) {
142    printf("Attempting to realloc unallocated memory at %p\n", ptr);
143    entry = malloc(sizeof(AllocationEntry));
144    if (entry == NULL) {
145      printf("Reallocator failure\n");
146      return NULL;
147    }
148    entry->allocation = realloc(ptr, size);
149    if (entry->allocation == NULL) {
150      free(entry);
151      return NULL;
152    }
153
154    /* Add to the list of allocations */
155    entry->next = NULL;
156    if (alloc_head == NULL) {
157      entry->prev = NULL;
158      alloc_head = alloc_tail = entry;
159    } else {
160      entry->prev = alloc_tail;
161      alloc_tail->next = entry;
162      alloc_tail = entry;
163    }
164  } else {
165    entry->allocation = realloc(ptr, size);
166    if (entry->allocation == NULL) {
167      /* Realloc semantics say the original is still allocated */
168      entry->allocation = ptr;
169      return NULL;
170    }
171  }
172
173  entry->num_bytes = size;
174  return entry->allocation;
175}
176
177int
178tracking_report(void) {
179  AllocationEntry *entry;
180
181  if (alloc_head == NULL)
182    return 1;
183
184  /* Otherwise we have allocations that haven't been freed */
185  for (entry = alloc_head; entry != NULL; entry = entry->next) {
186    printf("Allocated %lu bytes at %p\n", (long unsigned)entry->num_bytes,
187           entry->allocation);
188  }
189  return 0;
190}
191