1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3 * stdlib function definitions for NOLIBC
4 * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
5 */
6
7 #ifndef _NOLIBC_STDLIB_H
8 #define _NOLIBC_STDLIB_H
9
10 #include "std.h"
11 #include "arch.h"
12 #include "types.h"
13 #include "sys.h"
14 #include "string.h"
15
16 struct nolibc_heap {
17 size_t len;
18 char user_p[] __attribute__((__aligned__));
19 };
20
21 /* Buffer used to store int-to-ASCII conversions. Will only be implemented if
22 * any of the related functions is implemented. The area is large enough to
23 * store "18446744073709551615" or "-9223372036854775808" and the final zero.
24 */
25 static __attribute__((unused)) char itoa_buffer[21];
26
27 /*
28 * As much as possible, please keep functions alphabetically sorted.
29 */
30
31 /* must be exported, as it's used by libgcc for various divide functions */
32 __attribute__((weak,unused,noreturn,section(".text.nolibc_abort")))
abort(void)33 void abort(void)
34 {
35 sys_kill(sys_getpid(), SIGABRT);
36 for (;;);
37 }
38
39 static __attribute__((unused))
atol(const char * s)40 long atol(const char *s)
41 {
42 unsigned long ret = 0;
43 unsigned long d;
44 int neg = 0;
45
46 if (*s == '-') {
47 neg = 1;
48 s++;
49 }
50
51 while (1) {
52 d = (*s++) - '0';
53 if (d > 9)
54 break;
55 ret *= 10;
56 ret += d;
57 }
58
59 return neg ? -ret : ret;
60 }
61
62 static __attribute__((unused))
atoi(const char * s)63 int atoi(const char *s)
64 {
65 return atol(s);
66 }
67
68 static __attribute__((unused))
free(void * ptr)69 void free(void *ptr)
70 {
71 struct nolibc_heap *heap;
72
73 if (!ptr)
74 return;
75
76 heap = container_of(ptr, struct nolibc_heap, user_p);
77 munmap(heap, heap->len);
78 }
79
80 /* getenv() tries to find the environment variable named <name> in the
81 * environment array pointed to by global variable "environ" which must be
82 * declared as a char **, and must be terminated by a NULL (it is recommended
83 * to set this variable to the "envp" argument of main()). If the requested
84 * environment variable exists its value is returned otherwise NULL is
85 * returned. getenv() is forcefully inlined so that the reference to "environ"
86 * will be dropped if unused, even at -O0.
87 */
88 static __attribute__((unused))
_getenv(const char * name,char ** environ)89 char *_getenv(const char *name, char **environ)
90 {
91 int idx, i;
92
93 if (environ) {
94 for (idx = 0; environ[idx]; idx++) {
95 for (i = 0; name[i] && name[i] == environ[idx][i];)
96 i++;
97 if (!name[i] && environ[idx][i] == '=')
98 return &environ[idx][i+1];
99 }
100 }
101 return NULL;
102 }
103
104 static inline __attribute__((unused,always_inline))
getenv(const char * name)105 char *getenv(const char *name)
106 {
107 extern char **environ;
108 return _getenv(name, environ);
109 }
110
111 static __attribute__((unused))
malloc(size_t len)112 void *malloc(size_t len)
113 {
114 struct nolibc_heap *heap;
115
116 /* Always allocate memory with size multiple of 4096. */
117 len = sizeof(*heap) + len;
118 len = (len + 4095UL) & -4096UL;
119 heap = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
120 -1, 0);
121 if (__builtin_expect(heap == MAP_FAILED, 0))
122 return NULL;
123
124 heap->len = len;
125 return heap->user_p;
126 }
127
128 static __attribute__((unused))
calloc(size_t size,size_t nmemb)129 void *calloc(size_t size, size_t nmemb)
130 {
131 size_t x = size * nmemb;
132
133 if (__builtin_expect(size && ((x / size) != nmemb), 0)) {
134 SET_ERRNO(ENOMEM);
135 return NULL;
136 }
137
138 /*
139 * No need to zero the heap, the MAP_ANONYMOUS in malloc()
140 * already does it.
141 */
142 return malloc(x);
143 }
144
145 static __attribute__((unused))
realloc(void * old_ptr,size_t new_size)146 void *realloc(void *old_ptr, size_t new_size)
147 {
148 struct nolibc_heap *heap;
149 size_t user_p_len;
150 void *ret;
151
152 if (!old_ptr)
153 return malloc(new_size);
154
155 heap = container_of(old_ptr, struct nolibc_heap, user_p);
156 user_p_len = heap->len - sizeof(*heap);
157 /*
158 * Don't realloc() if @user_p_len >= @new_size, this block of
159 * memory is still enough to handle the @new_size. Just return
160 * the same pointer.
161 */
162 if (user_p_len >= new_size)
163 return old_ptr;
164
165 ret = malloc(new_size);
166 if (__builtin_expect(!ret, 0))
167 return NULL;
168
169 memcpy(ret, heap->user_p, heap->len);
170 munmap(heap, heap->len);
171 return ret;
172 }
173
174 /* Converts the unsigned long integer <in> to its hex representation into
175 * buffer <buffer>, which must be long enough to store the number and the
176 * trailing zero (17 bytes for "ffffffffffffffff" or 9 for "ffffffff"). The
177 * buffer is filled from the first byte, and the number of characters emitted
178 * (not counting the trailing zero) is returned. The function is constructed
179 * in a way to optimize the code size and avoid any divide that could add a
180 * dependency on large external functions.
181 */
182 static __attribute__((unused))
utoh_r(unsigned long in,char * buffer)183 int utoh_r(unsigned long in, char *buffer)
184 {
185 signed char pos = (~0UL > 0xfffffffful) ? 60 : 28;
186 int digits = 0;
187 int dig;
188
189 do {
190 dig = in >> pos;
191 in -= (uint64_t)dig << pos;
192 pos -= 4;
193 if (dig || digits || pos < 0) {
194 if (dig > 9)
195 dig += 'a' - '0' - 10;
196 buffer[digits++] = '0' + dig;
197 }
198 } while (pos >= 0);
199
200 buffer[digits] = 0;
201 return digits;
202 }
203
204 /* converts unsigned long <in> to an hex string using the static itoa_buffer
205 * and returns the pointer to that string.
206 */
207 static inline __attribute__((unused))
utoh(unsigned long in)208 char *utoh(unsigned long in)
209 {
210 utoh_r(in, itoa_buffer);
211 return itoa_buffer;
212 }
213
214 /* Converts the unsigned long integer <in> to its string representation into
215 * buffer <buffer>, which must be long enough to store the number and the
216 * trailing zero (21 bytes for 18446744073709551615 in 64-bit, 11 for
217 * 4294967295 in 32-bit). The buffer is filled from the first byte, and the
218 * number of characters emitted (not counting the trailing zero) is returned.
219 * The function is constructed in a way to optimize the code size and avoid
220 * any divide that could add a dependency on large external functions.
221 */
222 static __attribute__((unused))
utoa_r(unsigned long in,char * buffer)223 int utoa_r(unsigned long in, char *buffer)
224 {
225 unsigned long lim;
226 int digits = 0;
227 int pos = (~0UL > 0xfffffffful) ? 19 : 9;
228 int dig;
229
230 do {
231 for (dig = 0, lim = 1; dig < pos; dig++)
232 lim *= 10;
233
234 if (digits || in >= lim || !pos) {
235 for (dig = 0; in >= lim; dig++)
236 in -= lim;
237 buffer[digits++] = '0' + dig;
238 }
239 } while (pos--);
240
241 buffer[digits] = 0;
242 return digits;
243 }
244
245 /* Converts the signed long integer <in> to its string representation into
246 * buffer <buffer>, which must be long enough to store the number and the
247 * trailing zero (21 bytes for -9223372036854775808 in 64-bit, 12 for
248 * -2147483648 in 32-bit). The buffer is filled from the first byte, and the
249 * number of characters emitted (not counting the trailing zero) is returned.
250 */
251 static __attribute__((unused))
itoa_r(long in,char * buffer)252 int itoa_r(long in, char *buffer)
253 {
254 char *ptr = buffer;
255 int len = 0;
256
257 if (in < 0) {
258 in = -in;
259 *(ptr++) = '-';
260 len++;
261 }
262 len += utoa_r(in, ptr);
263 return len;
264 }
265
266 /* for historical compatibility, same as above but returns the pointer to the
267 * buffer.
268 */
269 static inline __attribute__((unused))
ltoa_r(long in,char * buffer)270 char *ltoa_r(long in, char *buffer)
271 {
272 itoa_r(in, buffer);
273 return buffer;
274 }
275
276 /* converts long integer <in> to a string using the static itoa_buffer and
277 * returns the pointer to that string.
278 */
279 static inline __attribute__((unused))
itoa(long in)280 char *itoa(long in)
281 {
282 itoa_r(in, itoa_buffer);
283 return itoa_buffer;
284 }
285
286 /* converts long integer <in> to a string using the static itoa_buffer and
287 * returns the pointer to that string. Same as above, for compatibility.
288 */
289 static inline __attribute__((unused))
ltoa(long in)290 char *ltoa(long in)
291 {
292 itoa_r(in, itoa_buffer);
293 return itoa_buffer;
294 }
295
296 /* converts unsigned long integer <in> to a string using the static itoa_buffer
297 * and returns the pointer to that string.
298 */
299 static inline __attribute__((unused))
utoa(unsigned long in)300 char *utoa(unsigned long in)
301 {
302 utoa_r(in, itoa_buffer);
303 return itoa_buffer;
304 }
305
306 /* Converts the unsigned 64-bit integer <in> to its hex representation into
307 * buffer <buffer>, which must be long enough to store the number and the
308 * trailing zero (17 bytes for "ffffffffffffffff"). The buffer is filled from
309 * the first byte, and the number of characters emitted (not counting the
310 * trailing zero) is returned. The function is constructed in a way to optimize
311 * the code size and avoid any divide that could add a dependency on large
312 * external functions.
313 */
314 static __attribute__((unused))
u64toh_r(uint64_t in,char * buffer)315 int u64toh_r(uint64_t in, char *buffer)
316 {
317 signed char pos = 60;
318 int digits = 0;
319 int dig;
320
321 do {
322 if (sizeof(long) >= 8) {
323 dig = (in >> pos) & 0xF;
324 } else {
325 /* 32-bit platforms: avoid a 64-bit shift */
326 uint32_t d = (pos >= 32) ? (in >> 32) : in;
327 dig = (d >> (pos & 31)) & 0xF;
328 }
329 if (dig > 9)
330 dig += 'a' - '0' - 10;
331 pos -= 4;
332 if (dig || digits || pos < 0)
333 buffer[digits++] = '0' + dig;
334 } while (pos >= 0);
335
336 buffer[digits] = 0;
337 return digits;
338 }
339
340 /* converts uint64_t <in> to an hex string using the static itoa_buffer and
341 * returns the pointer to that string.
342 */
343 static inline __attribute__((unused))
u64toh(uint64_t in)344 char *u64toh(uint64_t in)
345 {
346 u64toh_r(in, itoa_buffer);
347 return itoa_buffer;
348 }
349
350 /* Converts the unsigned 64-bit integer <in> to its string representation into
351 * buffer <buffer>, which must be long enough to store the number and the
352 * trailing zero (21 bytes for 18446744073709551615). The buffer is filled from
353 * the first byte, and the number of characters emitted (not counting the
354 * trailing zero) is returned. The function is constructed in a way to optimize
355 * the code size and avoid any divide that could add a dependency on large
356 * external functions.
357 */
358 static __attribute__((unused))
u64toa_r(uint64_t in,char * buffer)359 int u64toa_r(uint64_t in, char *buffer)
360 {
361 unsigned long long lim;
362 int digits = 0;
363 int pos = 19; /* start with the highest possible digit */
364 int dig;
365
366 do {
367 for (dig = 0, lim = 1; dig < pos; dig++)
368 lim *= 10;
369
370 if (digits || in >= lim || !pos) {
371 for (dig = 0; in >= lim; dig++)
372 in -= lim;
373 buffer[digits++] = '0' + dig;
374 }
375 } while (pos--);
376
377 buffer[digits] = 0;
378 return digits;
379 }
380
381 /* Converts the signed 64-bit integer <in> to its string representation into
382 * buffer <buffer>, which must be long enough to store the number and the
383 * trailing zero (21 bytes for -9223372036854775808). The buffer is filled from
384 * the first byte, and the number of characters emitted (not counting the
385 * trailing zero) is returned.
386 */
387 static __attribute__((unused))
i64toa_r(int64_t in,char * buffer)388 int i64toa_r(int64_t in, char *buffer)
389 {
390 char *ptr = buffer;
391 int len = 0;
392
393 if (in < 0) {
394 in = -in;
395 *(ptr++) = '-';
396 len++;
397 }
398 len += u64toa_r(in, ptr);
399 return len;
400 }
401
402 /* converts int64_t <in> to a string using the static itoa_buffer and returns
403 * the pointer to that string.
404 */
405 static inline __attribute__((unused))
i64toa(int64_t in)406 char *i64toa(int64_t in)
407 {
408 i64toa_r(in, itoa_buffer);
409 return itoa_buffer;
410 }
411
412 /* converts uint64_t <in> to a string using the static itoa_buffer and returns
413 * the pointer to that string.
414 */
415 static inline __attribute__((unused))
u64toa(uint64_t in)416 char *u64toa(uint64_t in)
417 {
418 u64toa_r(in, itoa_buffer);
419 return itoa_buffer;
420 }
421
422 /* make sure to include all global symbols */
423 #include "nolibc.h"
424
425 #endif /* _NOLIBC_STDLIB_H */
426