-
Notifications
You must be signed in to change notification settings - Fork 0
/
malloc.c
286 lines (274 loc) · 7.92 KB
/
malloc.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
#include "malloc.h"
#include "mem.h"
#include <stdbool.h>
#include <stddef.h>
extern uint32_t __heap_base;
extern uint32_t __global_base;
extern uint32_t __data_end;
extern uint32_t __stack_low;
extern uint32_t __stack_high;
struct block {
uint32_t size;
struct block* next;
char data[];
};
struct block* head = NULL;
#define USER_DATA_START(blk) ((uint32_t)(blk) + offsetof(struct block, data))
#define USER_DATA_END(blk) (USER_DATA_START(blk) + (blk)->size)
#define REMOVE_BLOCK_META(blk) ((uint32_t)(blk) - offsetof(struct block, data))
#define MEMORY_SIZE (__builtin_wasm_memory_size(0) * (64 * 1024))
#define VALID_ADDR(addr, n) (((uint32_t)(addr) + ((n) - 1)) < MEMORY_SIZE)
void validateAccess(void* addr, uint32_t size) {
if ((addr >= (void*)&__global_base && addr + size <= (void*)&__data_end) ||
(addr >= (void*)&__stack_low && addr + size <= (void*)&__stack_high))
return;
struct block* current = head;
while (current) {
if ((uint32_t)addr >= USER_DATA_START(current) && (uint32_t)addr + size <= USER_DATA_END(current))
return;
current = current->next;
}
__builtin_trap();
}
__attribute__((visibility("default")))
int8_t readInt8(void* addr) {
validateAccess(addr, sizeof(int8_t));
return *(int8_t*)addr;
}
__attribute__((visibility("default")))
uint8_t readUint8(void* addr) {
validateAccess(addr, sizeof(uint8_t));
return *(uint8_t*)addr;
}
__attribute__((visibility("default")))
int16_t readInt16(void* addr) {
validateAccess(addr, sizeof(int16_t));
return *(int16_t*)addr;
}
__attribute__((visibility("default")))
uint16_t readUint16(void* addr) {
validateAccess(addr, sizeof(uint16_t));
return *(uint16_t*)addr;
}
__attribute__((visibility("default")))
int32_t readInt32(void* addr) {
validateAccess(addr, sizeof(int32_t));
return *(int32_t*)addr;
}
__attribute__((visibility("default")))
uint32_t readUint32(void* addr) {
validateAccess(addr, sizeof(uint32_t));
return *(uint32_t*)addr;
}
__attribute__((visibility("default")))
int64_t readInt64(void* addr) {
validateAccess(addr, sizeof(int64_t));
return *(int64_t*)addr;
}
__attribute__((visibility("default")))
uint64_t readUint64(void* addr) {
validateAccess(addr, sizeof(uint64_t));
return *(uint64_t*)addr;
}
__attribute__((visibility("default")))
float readFloat(void* addr) {
validateAccess(addr, sizeof(float));
return *(float*)addr;
}
__attribute__((visibility("default")))
double readDouble(void* addr) {
validateAccess(addr, sizeof(double));
return *(double*)addr;
}
__attribute__((visibility("default")))
int8_t writeInt8(void* addr, int8_t value) {
validateAccess(addr, sizeof(int8_t));
return *(int8_t*)addr = value;
}
__attribute__((visibility("default")))
uint8_t writeUint8(void* addr, uint8_t value) {
validateAccess(addr, sizeof(uint8_t));
return *(uint8_t*)addr = value;
}
__attribute__((visibility("default")))
int16_t writeInt16(void* addr, int16_t value) {
validateAccess(addr, sizeof(int16_t));
return *(int16_t*)addr = value;
}
__attribute__((visibility("default")))
uint16_t writeUint16(void* addr, uint16_t value) {
validateAccess(addr, sizeof(uint16_t));
return *(uint16_t*)addr = value;
}
__attribute__((visibility("default")))
int32_t writeInt32(void* addr, int32_t value) {
validateAccess(addr, sizeof(int32_t));
return *(int32_t*)addr = value;
}
__attribute__((visibility("default")))
uint32_t writeUint32(void* addr, uint32_t value) {
validateAccess(addr, sizeof(uint32_t));
return *(uint32_t*)addr = value;
}
__attribute__((visibility("default")))
int64_t writeInt64(void* addr, int64_t value) {
validateAccess(addr, sizeof(int64_t));
return *(int64_t*)addr = value;
}
__attribute__((visibility("default")))
uint64_t writeUint64(void* addr, uint64_t value) {
validateAccess(addr, sizeof(uint64_t));
return *(uint64_t*)addr = value;
}
__attribute__((visibility("default")))
float writeFloat(void* addr, float value) {
validateAccess(addr, sizeof(float));
return *(float*)addr = value;
}
__attribute__((visibility("default")))
double writeDouble(void* addr, double value) {
validateAccess(addr, sizeof(double));
return *(double*)addr = value;
}
__attribute__((visibility("default")))
void* malloc(uint32_t size) {
if (size == 0)
return NULL;
struct block* current = head;
if (!current) {
struct block* newBlock = (struct block*)&__heap_base;
{
uint32_t res;
if (__builtin_add_overflow(offsetof(struct block, data), size, &res) ||
!VALID_ADDR(newBlock, res))
return NULL;
}
newBlock->size = size;
newBlock->next = NULL;
head = newBlock;
return (void*)USER_DATA_START(head);
}
uint32_t bestSize = UINT32_MAX;
struct block* bestBlock = NULL;
bool isBestBeforeHead = false;
if (current > (struct block*)&__heap_base) {
uint32_t freeSpace = (uint32_t)current - USER_DATA_START(&__heap_base);
if (freeSpace >= size) {
bestSize = freeSpace;
isBestBeforeHead = true;
}
}
while (current) {
struct block* nextBlock = current->next;
uint32_t freeSpace;
if (nextBlock)
freeSpace = (uint32_t)nextBlock - USER_DATA_END(current);
else freeSpace = MEMORY_SIZE - USER_DATA_END(current);
if (freeSpace < offsetof(struct block, data)) {
current = nextBlock;
continue;
}
freeSpace = REMOVE_BLOCK_META(freeSpace);
if (freeSpace >= size && freeSpace < bestSize) {
bestSize = freeSpace;
bestBlock = current;
if (isBestBeforeHead)
isBestBeforeHead = false;
if (freeSpace == size)
break;
}
current = nextBlock;
}
if (!bestBlock)
return NULL;
if (isBestBeforeHead) {
struct block* newBlock = (struct block*)&__heap_base;
if (!VALID_ADDR(newBlock, offsetof(struct block, data) + size))
return NULL;
newBlock->size = size;
newBlock->next = head;
head = newBlock;
return (void*)USER_DATA_START(newBlock);
}
struct block* newBlock = (struct block*)USER_DATA_END(bestBlock);
if (!VALID_ADDR(newBlock, offsetof(struct block, data) + size))
return NULL;
newBlock->size = size;
newBlock->next = bestBlock->next;
bestBlock->next = newBlock;
return (void*)USER_DATA_START(newBlock);
}
__attribute__((visibility("default")))
void* calloc(uint32_t nmemb, uint32_t size) {
uint32_t res = 0;
if (__builtin_mul_overflow(size, nmemb, &res))
return NULL;
void* ptr = malloc(res);
if (ptr)
memset(ptr, '\0', res);
return ptr;
}
__attribute__((visibility("default")))
void free(void* ptr) {
struct block* prev = NULL;
struct block* current = head;
struct block* next = NULL;
while (current) {
next = current->next;
if ((void*)USER_DATA_START(current) == ptr)
break;
prev = current;
current = next;
}
if (!current)
return;
if (!prev)
head = next;
else prev->next = next;
return;
}
__attribute__((visibility("default")))
void* realloc(void* ptr, uint32_t size) {
if (size == 0) {
if (ptr != NULL)
free(ptr);
return NULL;
} else if (ptr == NULL)
return malloc(size);
struct block* current = head;
while (current) {
if ((void*)USER_DATA_START(current) == ptr)
break;
current = current->next;
}
if (!current)
return NULL;
if (current->size == size)
return (void*)USER_DATA_START(current);
{
struct block* next = current->next;
uint32_t freeSpace;
if (next)
freeSpace = (uint32_t)next - USER_DATA_START(current);
else freeSpace = MEMORY_SIZE - USER_DATA_START(current);
if (freeSpace >= size) {
if (!VALID_ADDR(current, offsetof(struct block, data) + size))
return NULL;
current->size = size;
return (void*)USER_DATA_START(current);
}
}
void* newPtr = malloc(size);
if (!newPtr)
return NULL;
memcpy(newPtr, ptr, current->size);
free(ptr);
return newPtr;
}
__attribute__((visibility("default")))
void* reallocarray(void* ptr, uint32_t nmemb, uint32_t size) {
uint32_t res = 0;
if (__builtin_mul_overflow(size, nmemb, &res))
return NULL;
return realloc(ptr, res);
}