xref: /linux/tools/include/nolibc/stdlib.h (revision 981368e1440b76f68b1ac8f5fb14e739f80ecc4e) 
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")))
34 void abort(void)
35 {
36 	sys_kill(sys_getpid(), SIGABRT);
37 	for (;;);
38 }
39 
40 static __attribute__((unused))
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))
64 int atoi(const char *s)
65 {
66 	return atol(s);
67 }
68 
69 static __attribute__((unused))
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.
87  */
88 static __attribute__((unused))
89 char *getenv(const char *name)
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 __attribute__((unused))
105 unsigned long getauxval(unsigned long type)
106 {
107 	const unsigned long *auxv = _auxv;
108 	unsigned long ret;
109 
110 	if (!auxv)
111 		return 0;
112 
113 	while (1) {
114 		if (!auxv[0] && !auxv[1]) {
115 			ret = 0;
116 			break;
117 		}
118 
119 		if (auxv[0] == type) {
120 			ret = auxv[1];
121 			break;
122 		}
123 
124 		auxv += 2;
125 	}
126 
127 	return ret;
128 }
129 
130 static __attribute__((unused))
131 void *malloc(size_t len)
132 {
133 	struct nolibc_heap *heap;
134 
135 	/* Always allocate memory with size multiple of 4096. */
136 	len  = sizeof(*heap) + len;
137 	len  = (len + 4095UL) & -4096UL;
138 	heap = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
139 		    -1, 0);
140 	if (__builtin_expect(heap == MAP_FAILED, 0))
141 		return NULL;
142 
143 	heap->len = len;
144 	return heap->user_p;
145 }
146 
147 static __attribute__((unused))
148 void *calloc(size_t size, size_t nmemb)
149 {
150 	size_t x = size * nmemb;
151 
152 	if (__builtin_expect(size && ((x / size) != nmemb), 0)) {
153 		SET_ERRNO(ENOMEM);
154 		return NULL;
155 	}
156 
157 	/*
158 	 * No need to zero the heap, the MAP_ANONYMOUS in malloc()
159 	 * already does it.
160 	 */
161 	return malloc(x);
162 }
163 
164 static __attribute__((unused))
165 void *realloc(void *old_ptr, size_t new_size)
166 {
167 	struct nolibc_heap *heap;
168 	size_t user_p_len;
169 	void *ret;
170 
171 	if (!old_ptr)
172 		return malloc(new_size);
173 
174 	heap = container_of(old_ptr, struct nolibc_heap, user_p);
175 	user_p_len = heap->len - sizeof(*heap);
176 	/*
177 	 * Don't realloc() if @user_p_len >= @new_size, this block of
178 	 * memory is still enough to handle the @new_size. Just return
179 	 * the same pointer.
180 	 */
181 	if (user_p_len >= new_size)
182 		return old_ptr;
183 
184 	ret = malloc(new_size);
185 	if (__builtin_expect(!ret, 0))
186 		return NULL;
187 
188 	memcpy(ret, heap->user_p, heap->len);
189 	munmap(heap, heap->len);
190 	return ret;
191 }
192 
193 /* Converts the unsigned long integer <in> to its hex representation into
194  * buffer <buffer>, which must be long enough to store the number and the
195  * trailing zero (17 bytes for "ffffffffffffffff" or 9 for "ffffffff"). The
196  * buffer is filled from the first byte, and the number of characters emitted
197  * (not counting the trailing zero) is returned. The function is constructed
198  * in a way to optimize the code size and avoid any divide that could add a
199  * dependency on large external functions.
200  */
201 static __attribute__((unused))
202 int utoh_r(unsigned long in, char *buffer)
203 {
204 	signed char pos = (~0UL > 0xfffffffful) ? 60 : 28;
205 	int digits = 0;
206 	int dig;
207 
208 	do {
209 		dig = in >> pos;
210 		in -= (uint64_t)dig << pos;
211 		pos -= 4;
212 		if (dig || digits || pos < 0) {
213 			if (dig > 9)
214 				dig += 'a' - '0' - 10;
215 			buffer[digits++] = '0' + dig;
216 		}
217 	} while (pos >= 0);
218 
219 	buffer[digits] = 0;
220 	return digits;
221 }
222 
223 /* converts unsigned long <in> to an hex string using the static itoa_buffer
224  * and returns the pointer to that string.
225  */
226 static __inline__ __attribute__((unused))
227 char *utoh(unsigned long in)
228 {
229 	utoh_r(in, itoa_buffer);
230 	return itoa_buffer;
231 }
232 
233 /* Converts the unsigned long integer <in> to its string representation into
234  * buffer <buffer>, which must be long enough to store the number and the
235  * trailing zero (21 bytes for 18446744073709551615 in 64-bit, 11 for
236  * 4294967295 in 32-bit). The buffer is filled from the first byte, and the
237  * number of characters emitted (not counting the trailing zero) is returned.
238  * The function is constructed in a way to optimize the code size and avoid
239  * any divide that could add a dependency on large external functions.
240  */
241 static __attribute__((unused))
242 int utoa_r(unsigned long in, char *buffer)
243 {
244 	unsigned long lim;
245 	int digits = 0;
246 	int pos = (~0UL > 0xfffffffful) ? 19 : 9;
247 	int dig;
248 
249 	do {
250 		for (dig = 0, lim = 1; dig < pos; dig++)
251 			lim *= 10;
252 
253 		if (digits || in >= lim || !pos) {
254 			for (dig = 0; in >= lim; dig++)
255 				in -= lim;
256 			buffer[digits++] = '0' + dig;
257 		}
258 	} while (pos--);
259 
260 	buffer[digits] = 0;
261 	return digits;
262 }
263 
264 /* Converts the signed long integer <in> to its string representation into
265  * buffer <buffer>, which must be long enough to store the number and the
266  * trailing zero (21 bytes for -9223372036854775808 in 64-bit, 12 for
267  * -2147483648 in 32-bit). The buffer is filled from the first byte, and the
268  * number of characters emitted (not counting the trailing zero) is returned.
269  */
270 static __attribute__((unused))
271 int itoa_r(long in, char *buffer)
272 {
273 	char *ptr = buffer;
274 	int len = 0;
275 
276 	if (in < 0) {
277 		in = -in;
278 		*(ptr++) = '-';
279 		len++;
280 	}
281 	len += utoa_r(in, ptr);
282 	return len;
283 }
284 
285 /* for historical compatibility, same as above but returns the pointer to the
286  * buffer.
287  */
288 static __inline__ __attribute__((unused))
289 char *ltoa_r(long in, char *buffer)
290 {
291 	itoa_r(in, buffer);
292 	return buffer;
293 }
294 
295 /* converts long integer <in> to a string using the static itoa_buffer and
296  * returns the pointer to that string.
297  */
298 static __inline__ __attribute__((unused))
299 char *itoa(long in)
300 {
301 	itoa_r(in, itoa_buffer);
302 	return itoa_buffer;
303 }
304 
305 /* converts long integer <in> to a string using the static itoa_buffer and
306  * returns the pointer to that string. Same as above, for compatibility.
307  */
308 static __inline__ __attribute__((unused))
309 char *ltoa(long in)
310 {
311 	itoa_r(in, itoa_buffer);
312 	return itoa_buffer;
313 }
314 
315 /* converts unsigned long integer <in> to a string using the static itoa_buffer
316  * and returns the pointer to that string.
317  */
318 static __inline__ __attribute__((unused))
319 char *utoa(unsigned long in)
320 {
321 	utoa_r(in, itoa_buffer);
322 	return itoa_buffer;
323 }
324 
325 /* Converts the unsigned 64-bit integer <in> to its hex representation into
326  * buffer <buffer>, which must be long enough to store the number and the
327  * trailing zero (17 bytes for "ffffffffffffffff"). The buffer is filled from
328  * the first byte, and the number of characters emitted (not counting the
329  * trailing zero) is returned. The function is constructed in a way to optimize
330  * the code size and avoid any divide that could add a dependency on large
331  * external functions.
332  */
333 static __attribute__((unused))
334 int u64toh_r(uint64_t in, char *buffer)
335 {
336 	signed char pos = 60;
337 	int digits = 0;
338 	int dig;
339 
340 	do {
341 		if (sizeof(long) >= 8) {
342 			dig = (in >> pos) & 0xF;
343 		} else {
344 			/* 32-bit platforms: avoid a 64-bit shift */
345 			uint32_t d = (pos >= 32) ? (in >> 32) : in;
346 			dig = (d >> (pos & 31)) & 0xF;
347 		}
348 		if (dig > 9)
349 			dig += 'a' - '0' - 10;
350 		pos -= 4;
351 		if (dig || digits || pos < 0)
352 			buffer[digits++] = '0' + dig;
353 	} while (pos >= 0);
354 
355 	buffer[digits] = 0;
356 	return digits;
357 }
358 
359 /* converts uint64_t <in> to an hex string using the static itoa_buffer and
360  * returns the pointer to that string.
361  */
362 static __inline__ __attribute__((unused))
363 char *u64toh(uint64_t in)
364 {
365 	u64toh_r(in, itoa_buffer);
366 	return itoa_buffer;
367 }
368 
369 /* Converts the unsigned 64-bit integer <in> to its string representation into
370  * buffer <buffer>, which must be long enough to store the number and the
371  * trailing zero (21 bytes for 18446744073709551615). The buffer is filled from
372  * the first byte, and the number of characters emitted (not counting the
373  * trailing zero) is returned. The function is constructed in a way to optimize
374  * the code size and avoid any divide that could add a dependency on large
375  * external functions.
376  */
377 static __attribute__((unused))
378 int u64toa_r(uint64_t in, char *buffer)
379 {
380 	unsigned long long lim;
381 	int digits = 0;
382 	int pos = 19; /* start with the highest possible digit */
383 	int dig;
384 
385 	do {
386 		for (dig = 0, lim = 1; dig < pos; dig++)
387 			lim *= 10;
388 
389 		if (digits || in >= lim || !pos) {
390 			for (dig = 0; in >= lim; dig++)
391 				in -= lim;
392 			buffer[digits++] = '0' + dig;
393 		}
394 	} while (pos--);
395 
396 	buffer[digits] = 0;
397 	return digits;
398 }
399 
400 /* Converts the signed 64-bit integer <in> to its string representation into
401  * buffer <buffer>, which must be long enough to store the number and the
402  * trailing zero (21 bytes for -9223372036854775808). The buffer is filled from
403  * the first byte, and the number of characters emitted (not counting the
404  * trailing zero) is returned.
405  */
406 static __attribute__((unused))
407 int i64toa_r(int64_t in, char *buffer)
408 {
409 	char *ptr = buffer;
410 	int len = 0;
411 
412 	if (in < 0) {
413 		in = -in;
414 		*(ptr++) = '-';
415 		len++;
416 	}
417 	len += u64toa_r(in, ptr);
418 	return len;
419 }
420 
421 /* converts int64_t <in> to a string using the static itoa_buffer and returns
422  * the pointer to that string.
423  */
424 static __inline__ __attribute__((unused))
425 char *i64toa(int64_t in)
426 {
427 	i64toa_r(in, itoa_buffer);
428 	return itoa_buffer;
429 }
430 
431 /* converts uint64_t <in> to a string using the static itoa_buffer and returns
432  * the pointer to that string.
433  */
434 static __inline__ __attribute__((unused))
435 char *u64toa(uint64_t in)
436 {
437 	u64toa_r(in, itoa_buffer);
438 	return itoa_buffer;
439 }
440 
441 /* make sure to include all global symbols */
442 #include "nolibc.h"
443 
444 #endif /* _NOLIBC_STDLIB_H */
445