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 #include <linux/auxvec.h>
16
17 struct nolibc_heap {
18 size_t len;
19 char user_p[] __attribute__((__aligned__));
20 };
21
22 /* Buffer used to store int-to-ASCII conversions. Will only be implemented if
23 * any of the related functions is implemented. The area is large enough to
24 * store "18446744073709551615" or "-9223372036854775808" and the final zero.
25 */
26 static __attribute__((unused)) char itoa_buffer[21];
27
28 /*
29 * As much as possible, please keep functions alphabetically sorted.
30 */
31
32 /* must be exported, as it's used by libgcc for various divide functions */
33 __attribute__((weak,unused,noreturn,section(".text.nolibc_abort")))
abort(void)34 void abort(void)
35 {
36 sys_kill(sys_getpid(), SIGABRT);
37 for (;;);
38 }
39
40 static __attribute__((unused))
atol(const char * s)41 long atol(const char *s)
42 {
43 unsigned long ret = 0;
44 unsigned long d;
45 int neg = 0;
46
47 if (*s == '-') {
48 neg = 1;
49 s++;
50 }
51
52 while (1) {
53 d = (*s++) - '0';
54 if (d > 9)
55 break;
56 ret *= 10;
57 ret += d;
58 }
59
60 return neg ? -ret : ret;
61 }
62
63 static __attribute__((unused))
atoi(const char * s)64 int atoi(const char *s)
65 {
66 return atol(s);
67 }
68
69 static __attribute__((unused))
free(void * ptr)70 void free(void *ptr)
71 {
72 struct nolibc_heap *heap;
73
74 if (!ptr)
75 return;
76
77 heap = container_of(ptr, struct nolibc_heap, user_p);
78 munmap(heap, heap->len);
79 }
80
81 /* getenv() tries to find the environment variable named <name> in the
82 * environment array pointed to by global variable "environ" which must be
83 * declared as a char **, and must be terminated by a NULL (it is recommended
84 * to set this variable to the "envp" argument of main()). If the requested
85 * environment variable exists its value is returned otherwise NULL is
86 * returned. getenv() is forcefully inlined so that the reference to "environ"
87 * will be dropped if unused, even at -O0.
88 */
89 static __attribute__((unused))
_getenv(const char * name,char ** environ)90 char *_getenv(const char *name, char **environ)
91 {
92 int idx, i;
93
94 if (environ) {
95 for (idx = 0; environ[idx]; idx++) {
96 for (i = 0; name[i] && name[i] == environ[idx][i];)
97 i++;
98 if (!name[i] && environ[idx][i] == '=')
99 return &environ[idx][i+1];
100 }
101 }
102 return NULL;
103 }
104
105 static inline __attribute__((unused,always_inline))
getenv(const char * name)106 char *getenv(const char *name)
107 {
108 extern char **environ;
109 return _getenv(name, environ);
110 }
111
112 static __attribute__((unused))
getauxval(unsigned long type)113 unsigned long getauxval(unsigned long type)
114 {
115 const unsigned long *auxv = _auxv;
116 unsigned long ret;
117
118 if (!auxv)
119 return 0;
120
121 while (1) {
122 if (!auxv[0] && !auxv[1]) {
123 ret = 0;
124 break;
125 }
126
127 if (auxv[0] == type) {
128 ret = auxv[1];
129 break;
130 }
131
132 auxv += 2;
133 }
134
135 return ret;
136 }
137
138 static __attribute__((unused))
malloc(size_t len)139 void *malloc(size_t len)
140 {
141 struct nolibc_heap *heap;
142
143 /* Always allocate memory with size multiple of 4096. */
144 len = sizeof(*heap) + len;
145 len = (len + 4095UL) & -4096UL;
146 heap = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
147 -1, 0);
148 if (__builtin_expect(heap == MAP_FAILED, 0))
149 return NULL;
150
151 heap->len = len;
152 return heap->user_p;
153 }
154
155 static __attribute__((unused))
calloc(size_t size,size_t nmemb)156 void *calloc(size_t size, size_t nmemb)
157 {
158 size_t x = size * nmemb;
159
160 if (__builtin_expect(size && ((x / size) != nmemb), 0)) {
161 SET_ERRNO(ENOMEM);
162 return NULL;
163 }
164
165 /*
166 * No need to zero the heap, the MAP_ANONYMOUS in malloc()
167 * already does it.
168 */
169 return malloc(x);
170 }
171
172 static __attribute__((unused))
realloc(void * old_ptr,size_t new_size)173 void *realloc(void *old_ptr, size_t new_size)
174 {
175 struct nolibc_heap *heap;
176 size_t user_p_len;
177 void *ret;
178
179 if (!old_ptr)
180 return malloc(new_size);
181
182 heap = container_of(old_ptr, struct nolibc_heap, user_p);
183 user_p_len = heap->len - sizeof(*heap);
184 /*
185 * Don't realloc() if @user_p_len >= @new_size, this block of
186 * memory is still enough to handle the @new_size. Just return
187 * the same pointer.
188 */
189 if (user_p_len >= new_size)
190 return old_ptr;
191
192 ret = malloc(new_size);
193 if (__builtin_expect(!ret, 0))
194 return NULL;
195
196 memcpy(ret, heap->user_p, heap->len);
197 munmap(heap, heap->len);
198 return ret;
199 }
200
201 /* Converts the unsigned long integer <in> to its hex representation into
202 * buffer <buffer>, which must be long enough to store the number and the
203 * trailing zero (17 bytes for "ffffffffffffffff" or 9 for "ffffffff"). The
204 * buffer is filled from the first byte, and the number of characters emitted
205 * (not counting the trailing zero) is returned. The function is constructed
206 * in a way to optimize the code size and avoid any divide that could add a
207 * dependency on large external functions.
208 */
209 static __attribute__((unused))
utoh_r(unsigned long in,char * buffer)210 int utoh_r(unsigned long in, char *buffer)
211 {
212 signed char pos = (~0UL > 0xfffffffful) ? 60 : 28;
213 int digits = 0;
214 int dig;
215
216 do {
217 dig = in >> pos;
218 in -= (uint64_t)dig << pos;
219 pos -= 4;
220 if (dig || digits || pos < 0) {
221 if (dig > 9)
222 dig += 'a' - '0' - 10;
223 buffer[digits++] = '0' + dig;
224 }
225 } while (pos >= 0);
226
227 buffer[digits] = 0;
228 return digits;
229 }
230
231 /* converts unsigned long <in> to an hex string using the static itoa_buffer
232 * and returns the pointer to that string.
233 */
234 static inline __attribute__((unused))
utoh(unsigned long in)235 char *utoh(unsigned long in)
236 {
237 utoh_r(in, itoa_buffer);
238 return itoa_buffer;
239 }
240
241 /* Converts the unsigned long integer <in> to its string representation into
242 * buffer <buffer>, which must be long enough to store the number and the
243 * trailing zero (21 bytes for 18446744073709551615 in 64-bit, 11 for
244 * 4294967295 in 32-bit). The buffer is filled from the first byte, and the
245 * number of characters emitted (not counting the trailing zero) is returned.
246 * The function is constructed in a way to optimize the code size and avoid
247 * any divide that could add a dependency on large external functions.
248 */
249 static __attribute__((unused))
utoa_r(unsigned long in,char * buffer)250 int utoa_r(unsigned long in, char *buffer)
251 {
252 unsigned long lim;
253 int digits = 0;
254 int pos = (~0UL > 0xfffffffful) ? 19 : 9;
255 int dig;
256
257 do {
258 for (dig = 0, lim = 1; dig < pos; dig++)
259 lim *= 10;
260
261 if (digits || in >= lim || !pos) {
262 for (dig = 0; in >= lim; dig++)
263 in -= lim;
264 buffer[digits++] = '0' + dig;
265 }
266 } while (pos--);
267
268 buffer[digits] = 0;
269 return digits;
270 }
271
272 /* Converts the signed long integer <in> to its string representation into
273 * buffer <buffer>, which must be long enough to store the number and the
274 * trailing zero (21 bytes for -9223372036854775808 in 64-bit, 12 for
275 * -2147483648 in 32-bit). The buffer is filled from the first byte, and the
276 * number of characters emitted (not counting the trailing zero) is returned.
277 */
278 static __attribute__((unused))
itoa_r(long in,char * buffer)279 int itoa_r(long in, char *buffer)
280 {
281 char *ptr = buffer;
282 int len = 0;
283
284 if (in < 0) {
285 in = -in;
286 *(ptr++) = '-';
287 len++;
288 }
289 len += utoa_r(in, ptr);
290 return len;
291 }
292
293 /* for historical compatibility, same as above but returns the pointer to the
294 * buffer.
295 */
296 static inline __attribute__((unused))
ltoa_r(long in,char * buffer)297 char *ltoa_r(long in, char *buffer)
298 {
299 itoa_r(in, buffer);
300 return buffer;
301 }
302
303 /* converts long integer <in> to a string using the static itoa_buffer and
304 * returns the pointer to that string.
305 */
306 static inline __attribute__((unused))
itoa(long in)307 char *itoa(long in)
308 {
309 itoa_r(in, itoa_buffer);
310 return itoa_buffer;
311 }
312
313 /* converts long integer <in> to a string using the static itoa_buffer and
314 * returns the pointer to that string. Same as above, for compatibility.
315 */
316 static inline __attribute__((unused))
ltoa(long in)317 char *ltoa(long in)
318 {
319 itoa_r(in, itoa_buffer);
320 return itoa_buffer;
321 }
322
323 /* converts unsigned long integer <in> to a string using the static itoa_buffer
324 * and returns the pointer to that string.
325 */
326 static inline __attribute__((unused))
utoa(unsigned long in)327 char *utoa(unsigned long in)
328 {
329 utoa_r(in, itoa_buffer);
330 return itoa_buffer;
331 }
332
333 /* Converts the unsigned 64-bit integer <in> to its hex representation into
334 * buffer <buffer>, which must be long enough to store the number and the
335 * trailing zero (17 bytes for "ffffffffffffffff"). The buffer is filled from
336 * the first byte, and the number of characters emitted (not counting the
337 * trailing zero) is returned. The function is constructed in a way to optimize
338 * the code size and avoid any divide that could add a dependency on large
339 * external functions.
340 */
341 static __attribute__((unused))
u64toh_r(uint64_t in,char * buffer)342 int u64toh_r(uint64_t in, char *buffer)
343 {
344 signed char pos = 60;
345 int digits = 0;
346 int dig;
347
348 do {
349 if (sizeof(long) >= 8) {
350 dig = (in >> pos) & 0xF;
351 } else {
352 /* 32-bit platforms: avoid a 64-bit shift */
353 uint32_t d = (pos >= 32) ? (in >> 32) : in;
354 dig = (d >> (pos & 31)) & 0xF;
355 }
356 if (dig > 9)
357 dig += 'a' - '0' - 10;
358 pos -= 4;
359 if (dig || digits || pos < 0)
360 buffer[digits++] = '0' + dig;
361 } while (pos >= 0);
362
363 buffer[digits] = 0;
364 return digits;
365 }
366
367 /* converts uint64_t <in> to an hex string using the static itoa_buffer and
368 * returns the pointer to that string.
369 */
370 static inline __attribute__((unused))
u64toh(uint64_t in)371 char *u64toh(uint64_t in)
372 {
373 u64toh_r(in, itoa_buffer);
374 return itoa_buffer;
375 }
376
377 /* Converts the unsigned 64-bit integer <in> to its string representation into
378 * buffer <buffer>, which must be long enough to store the number and the
379 * trailing zero (21 bytes for 18446744073709551615). The buffer is filled from
380 * the first byte, and the number of characters emitted (not counting the
381 * trailing zero) is returned. The function is constructed in a way to optimize
382 * the code size and avoid any divide that could add a dependency on large
383 * external functions.
384 */
385 static __attribute__((unused))
u64toa_r(uint64_t in,char * buffer)386 int u64toa_r(uint64_t in, char *buffer)
387 {
388 unsigned long long lim;
389 int digits = 0;
390 int pos = 19; /* start with the highest possible digit */
391 int dig;
392
393 do {
394 for (dig = 0, lim = 1; dig < pos; dig++)
395 lim *= 10;
396
397 if (digits || in >= lim || !pos) {
398 for (dig = 0; in >= lim; dig++)
399 in -= lim;
400 buffer[digits++] = '0' + dig;
401 }
402 } while (pos--);
403
404 buffer[digits] = 0;
405 return digits;
406 }
407
408 /* Converts the signed 64-bit integer <in> to its string representation into
409 * buffer <buffer>, which must be long enough to store the number and the
410 * trailing zero (21 bytes for -9223372036854775808). The buffer is filled from
411 * the first byte, and the number of characters emitted (not counting the
412 * trailing zero) is returned.
413 */
414 static __attribute__((unused))
i64toa_r(int64_t in,char * buffer)415 int i64toa_r(int64_t in, char *buffer)
416 {
417 char *ptr = buffer;
418 int len = 0;
419
420 if (in < 0) {
421 in = -in;
422 *(ptr++) = '-';
423 len++;
424 }
425 len += u64toa_r(in, ptr);
426 return len;
427 }
428
429 /* converts int64_t <in> to a string using the static itoa_buffer and returns
430 * the pointer to that string.
431 */
432 static inline __attribute__((unused))
i64toa(int64_t in)433 char *i64toa(int64_t in)
434 {
435 i64toa_r(in, itoa_buffer);
436 return itoa_buffer;
437 }
438
439 /* converts uint64_t <in> to a string using the static itoa_buffer and returns
440 * the pointer to that string.
441 */
442 static inline __attribute__((unused))
u64toa(uint64_t in)443 char *u64toa(uint64_t in)
444 {
445 u64toa_r(in, itoa_buffer);
446 return itoa_buffer;
447 }
448
449 /* make sure to include all global symbols */
450 #include "nolibc.h"
451
452 #endif /* _NOLIBC_STDLIB_H */
453