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
287
288
289
290
291
292
293
294
|
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* string function definitions for NOLIBC
* Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
*/
#ifndef _NOLIBC_STRING_H
#define _NOLIBC_STRING_H
#include "std.h"
static void *malloc(size_t len);
/*
* As much as possible, please keep functions alphabetically sorted.
*/
static __attribute__((unused))
int memcmp(const void *s1, const void *s2, size_t n)
{
size_t ofs = 0;
int c1 = 0;
while (ofs < n && !(c1 = ((unsigned char *)s1)[ofs] - ((unsigned char *)s2)[ofs])) {
ofs++;
}
return c1;
}
static __attribute__((unused))
void *_nolibc_memcpy_up(void *dst, const void *src, size_t len)
{
size_t pos = 0;
while (pos < len) {
((char *)dst)[pos] = ((const char *)src)[pos];
pos++;
}
return dst;
}
static __attribute__((unused))
void *_nolibc_memcpy_down(void *dst, const void *src, size_t len)
{
while (len) {
len--;
((char *)dst)[len] = ((const char *)src)[len];
}
return dst;
}
/* might be ignored by the compiler without -ffreestanding, then found as
* missing.
*/
__attribute__((weak,unused,section(".text.nolibc_memmove")))
void *memmove(void *dst, const void *src, size_t len)
{
size_t dir, pos;
pos = len;
dir = -1;
if (dst < src) {
pos = -1;
dir = 1;
}
while (len) {
pos += dir;
((char *)dst)[pos] = ((const char *)src)[pos];
len--;
}
return dst;
}
/* must be exported, as it's used by libgcc on ARM */
__attribute__((weak,unused,section(".text.nolibc_memcpy")))
void *memcpy(void *dst, const void *src, size_t len)
{
return _nolibc_memcpy_up(dst, src, len);
}
/* might be ignored by the compiler without -ffreestanding, then found as
* missing.
*/
__attribute__((weak,unused,section(".text.nolibc_memset")))
void *memset(void *dst, int b, size_t len)
{
char *p = dst;
while (len--) {
/* prevent gcc from recognizing memset() here */
__asm__ volatile("");
*(p++) = b;
}
return dst;
}
static __attribute__((unused))
char *strchr(const char *s, int c)
{
while (*s) {
if (*s == (char)c)
return (char *)s;
s++;
}
return NULL;
}
static __attribute__((unused))
int strcmp(const char *a, const char *b)
{
unsigned int c;
int diff;
while (!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
;
return diff;
}
static __attribute__((unused))
char *strcpy(char *dst, const char *src)
{
char *ret = dst;
while ((*dst++ = *src++));
return ret;
}
/* this function is only used with arguments that are not constants or when
* it's not known because optimizations are disabled. Note that gcc 12
* recognizes an strlen() pattern and replaces it with a jump to strlen(),
* thus itself, hence the asm() statement below that's meant to disable this
* confusing practice.
*/
static __attribute__((unused))
size_t strlen(const char *str)
{
size_t len;
for (len = 0; str[len]; len++)
__asm__("");
return len;
}
/* do not trust __builtin_constant_p() at -O0, as clang will emit a test and
* the two branches, then will rely on an external definition of strlen().
*/
#if defined(__OPTIMIZE__)
#define nolibc_strlen(x) strlen(x)
#define strlen(str) ({ \
__builtin_constant_p((str)) ? \
__builtin_strlen((str)) : \
nolibc_strlen((str)); \
})
#endif
static __attribute__((unused))
size_t strnlen(const char *str, size_t maxlen)
{
size_t len;
for (len = 0; (len < maxlen) && str[len]; len++);
return len;
}
static __attribute__((unused))
char *strdup(const char *str)
{
size_t len;
char *ret;
len = strlen(str);
ret = malloc(len + 1);
if (__builtin_expect(ret != NULL, 1))
memcpy(ret, str, len + 1);
return ret;
}
static __attribute__((unused))
char *strndup(const char *str, size_t maxlen)
{
size_t len;
char *ret;
len = strnlen(str, maxlen);
ret = malloc(len + 1);
if (__builtin_expect(ret != NULL, 1)) {
memcpy(ret, str, len);
ret[len] = '\0';
}
return ret;
}
static __attribute__((unused))
size_t strlcat(char *dst, const char *src, size_t size)
{
size_t len;
char c;
for (len = 0; dst[len]; len++)
;
for (;;) {
c = *src;
if (len < size)
dst[len] = c;
if (!c)
break;
len++;
src++;
}
return len;
}
static __attribute__((unused))
size_t strlcpy(char *dst, const char *src, size_t size)
{
size_t len;
char c;
for (len = 0;;) {
c = src[len];
if (len < size)
dst[len] = c;
if (!c)
break;
len++;
}
return len;
}
static __attribute__((unused))
char *strncat(char *dst, const char *src, size_t size)
{
char *orig = dst;
while (*dst)
dst++;
while (size && (*dst = *src)) {
src++;
dst++;
size--;
}
*dst = 0;
return orig;
}
static __attribute__((unused))
int strncmp(const char *a, const char *b, size_t size)
{
unsigned int c;
int diff = 0;
while (size-- &&
!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
;
return diff;
}
static __attribute__((unused))
char *strncpy(char *dst, const char *src, size_t size)
{
size_t len;
for (len = 0; len < size; len++)
if ((dst[len] = *src))
src++;
return dst;
}
static __attribute__((unused))
char *strrchr(const char *s, int c)
{
const char *ret = NULL;
while (*s) {
if (*s == (char)c)
ret = s;
s++;
}
return (char *)ret;
}
/* make sure to include all global symbols */
#include "nolibc.h"
#endif /* _NOLIBC_STRING_H */
|
