1 /* Debug allocators for the Expat test suite
2 __ __ _
3 ___\ \/ /_ __ __ _| |_
4 / _ \\ /| '_ \ / _` | __|
5 | __// \| |_) | (_| | |_
6 \___/_/\_\ .__/ \__,_|\__|
7 |_| XML parser
8
9 Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
10 Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
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
42 typedef struct allocation_entry {
43 struct allocation_entry *next;
44 struct allocation_entry *prev;
45 void *allocation;
46 size_t num_bytes;
47 } AllocationEntry;
48
49 static AllocationEntry *alloc_head = NULL;
50 static AllocationEntry *alloc_tail = NULL;
51
52 static AllocationEntry *find_allocation(void *ptr);
53
54 /* Allocate some memory and keep track of it. */
55 void *
56 tracking_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
84 static AllocationEntry *
85 find_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 */
97 void
98 tracking_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 */
125 void *
126 tracking_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
177 int
178 tracking_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 }