1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Convert integer string representation to an integer.
4 * If an integer doesn't fit into specified type, -E is returned.
5 *
6 * Integer starts with optional sign.
7 * kstrtou*() functions do not accept sign "-".
8 *
9 * Radix 0 means autodetection: leading "0x" implies radix 16,
10 * leading "0" implies radix 8, otherwise radix is 10.
11 * Autodetection hints work after optional sign, but not before.
12 *
13 * If -E is returned, result is not touched.
14 */
15#include <linux/ctype.h>
16#include <linux/errno.h>
17#include <linux/export.h>
18#include <linux/kstrtox.h>
19#include <linux/math64.h>
20#include <linux/types.h>
21#include <linux/uaccess.h>
22
23#include "kstrtox.h"
24
25noinline
26const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
27{
28 if (*base == 0) {
29 if (s[0] == '0') {
30 if (_tolower(c: s[1]) == 'x' && isxdigit(s[2]))
31 *base = 16;
32 else
33 *base = 8;
34 } else
35 *base = 10;
36 }
37 if (*base == 16 && s[0] == '0' && _tolower(c: s[1]) == 'x')
38 s += 2;
39 return s;
40}
41
42/*
43 * Convert non-negative integer string representation in explicitly given radix
44 * to an integer. A maximum of max_chars characters will be converted.
45 *
46 * Return number of characters consumed maybe or-ed with overflow bit.
47 * If overflow occurs, result integer (incorrect) is still returned.
48 *
49 * Don't you dare use this function.
50 */
51noinline
52unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
53 size_t max_chars)
54{
55 unsigned long long res;
56 unsigned int rv;
57
58 res = 0;
59 rv = 0;
60 while (max_chars--) {
61 unsigned int c = *s;
62 unsigned int lc = _tolower(c);
63 unsigned int val;
64
65 if ('0' <= c && c <= '9')
66 val = c - '0';
67 else if ('a' <= lc && lc <= 'f')
68 val = lc - 'a' + 10;
69 else
70 break;
71
72 if (val >= base)
73 break;
74 /*
75 * Check for overflow only if we are within range of
76 * it in the max base we support (16)
77 */
78 if (unlikely(res & (~0ull << 60))) {
79 if (res > div_u64(ULLONG_MAX - val, divisor: base))
80 rv |= KSTRTOX_OVERFLOW;
81 }
82 res = res * base + val;
83 rv++;
84 s++;
85 }
86 *p = res;
87 return rv;
88}
89
90noinline
91unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
92{
93 return _parse_integer_limit(s, base, p, INT_MAX);
94}
95
96static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
97{
98 unsigned long long _res;
99 unsigned int rv;
100
101 s = _parse_integer_fixup_radix(s, base: &base);
102 rv = _parse_integer(s, base, p: &_res);
103 if (rv & KSTRTOX_OVERFLOW)
104 return -ERANGE;
105 if (rv == 0)
106 return -EINVAL;
107 s += rv;
108 if (*s == '\n')
109 s++;
110 if (*s)
111 return -EINVAL;
112 *res = _res;
113 return 0;
114}
115
116/**
117 * kstrtoull - convert a string to an unsigned long long
118 * @s: The start of the string. The string must be null-terminated, and may also
119 * include a single newline before its terminating null. The first character
120 * may also be a plus sign, but not a minus sign.
121 * @base: The number base to use. The maximum supported base is 16. If base is
122 * given as 0, then the base of the string is automatically detected with the
123 * conventional semantics - If it begins with 0x the number will be parsed as a
124 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
125 * parsed as an octal number. Otherwise it will be parsed as a decimal.
126 * @res: Where to write the result of the conversion on success.
127 *
128 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
129 * Preferred over simple_strtoull(). Return code must be checked.
130 */
131noinline
132int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
133{
134 if (s[0] == '+')
135 s++;
136 return _kstrtoull(s, base, res);
137}
138EXPORT_SYMBOL(kstrtoull);
139
140/**
141 * kstrtoll - convert a string to a long long
142 * @s: The start of the string. The string must be null-terminated, and may also
143 * include a single newline before its terminating null. The first character
144 * may also be a plus sign or a minus sign.
145 * @base: The number base to use. The maximum supported base is 16. If base is
146 * given as 0, then the base of the string is automatically detected with the
147 * conventional semantics - If it begins with 0x the number will be parsed as a
148 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
149 * parsed as an octal number. Otherwise it will be parsed as a decimal.
150 * @res: Where to write the result of the conversion on success.
151 *
152 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
153 * Preferred over simple_strtoll(). Return code must be checked.
154 */
155noinline
156int kstrtoll(const char *s, unsigned int base, long long *res)
157{
158 unsigned long long tmp;
159 int rv;
160
161 if (s[0] == '-') {
162 rv = _kstrtoull(s: s + 1, base, res: &tmp);
163 if (rv < 0)
164 return rv;
165 if ((long long)-tmp > 0)
166 return -ERANGE;
167 *res = -tmp;
168 } else {
169 rv = kstrtoull(s, base, &tmp);
170 if (rv < 0)
171 return rv;
172 if ((long long)tmp < 0)
173 return -ERANGE;
174 *res = tmp;
175 }
176 return 0;
177}
178EXPORT_SYMBOL(kstrtoll);
179
180/* Internal, do not use. */
181int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
182{
183 unsigned long long tmp;
184 int rv;
185
186 rv = kstrtoull(s, base, &tmp);
187 if (rv < 0)
188 return rv;
189 if (tmp != (unsigned long)tmp)
190 return -ERANGE;
191 *res = tmp;
192 return 0;
193}
194EXPORT_SYMBOL(_kstrtoul);
195
196/* Internal, do not use. */
197int _kstrtol(const char *s, unsigned int base, long *res)
198{
199 long long tmp;
200 int rv;
201
202 rv = kstrtoll(s, base, &tmp);
203 if (rv < 0)
204 return rv;
205 if (tmp != (long)tmp)
206 return -ERANGE;
207 *res = tmp;
208 return 0;
209}
210EXPORT_SYMBOL(_kstrtol);
211
212/**
213 * kstrtouint - convert a string to an unsigned int
214 * @s: The start of the string. The string must be null-terminated, and may also
215 * include a single newline before its terminating null. The first character
216 * may also be a plus sign, but not a minus sign.
217 * @base: The number base to use. The maximum supported base is 16. If base is
218 * given as 0, then the base of the string is automatically detected with the
219 * conventional semantics - If it begins with 0x the number will be parsed as a
220 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
221 * parsed as an octal number. Otherwise it will be parsed as a decimal.
222 * @res: Where to write the result of the conversion on success.
223 *
224 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
225 * Preferred over simple_strtoul(). Return code must be checked.
226 */
227noinline
228int kstrtouint(const char *s, unsigned int base, unsigned int *res)
229{
230 unsigned long long tmp;
231 int rv;
232
233 rv = kstrtoull(s, base, &tmp);
234 if (rv < 0)
235 return rv;
236 if (tmp != (unsigned int)tmp)
237 return -ERANGE;
238 *res = tmp;
239 return 0;
240}
241EXPORT_SYMBOL(kstrtouint);
242
243/**
244 * kstrtoint - convert a string to an int
245 * @s: The start of the string. The string must be null-terminated, and may also
246 * include a single newline before its terminating null. The first character
247 * may also be a plus sign or a minus sign.
248 * @base: The number base to use. The maximum supported base is 16. If base is
249 * given as 0, then the base of the string is automatically detected with the
250 * conventional semantics - If it begins with 0x the number will be parsed as a
251 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
252 * parsed as an octal number. Otherwise it will be parsed as a decimal.
253 * @res: Where to write the result of the conversion on success.
254 *
255 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
256 * Preferred over simple_strtol(). Return code must be checked.
257 */
258noinline
259int kstrtoint(const char *s, unsigned int base, int *res)
260{
261 long long tmp;
262 int rv;
263
264 rv = kstrtoll(s, base, &tmp);
265 if (rv < 0)
266 return rv;
267 if (tmp != (int)tmp)
268 return -ERANGE;
269 *res = tmp;
270 return 0;
271}
272EXPORT_SYMBOL(kstrtoint);
273
274noinline
275int kstrtou16(const char *s, unsigned int base, u16 *res)
276{
277 unsigned long long tmp;
278 int rv;
279
280 rv = kstrtoull(s, base, &tmp);
281 if (rv < 0)
282 return rv;
283 if (tmp != (u16)tmp)
284 return -ERANGE;
285 *res = tmp;
286 return 0;
287}
288EXPORT_SYMBOL(kstrtou16);
289
290noinline
291int kstrtos16(const char *s, unsigned int base, s16 *res)
292{
293 long long tmp;
294 int rv;
295
296 rv = kstrtoll(s, base, &tmp);
297 if (rv < 0)
298 return rv;
299 if (tmp != (s16)tmp)
300 return -ERANGE;
301 *res = tmp;
302 return 0;
303}
304EXPORT_SYMBOL(kstrtos16);
305
306noinline
307int kstrtou8(const char *s, unsigned int base, u8 *res)
308{
309 unsigned long long tmp;
310 int rv;
311
312 rv = kstrtoull(s, base, &tmp);
313 if (rv < 0)
314 return rv;
315 if (tmp != (u8)tmp)
316 return -ERANGE;
317 *res = tmp;
318 return 0;
319}
320EXPORT_SYMBOL(kstrtou8);
321
322noinline
323int kstrtos8(const char *s, unsigned int base, s8 *res)
324{
325 long long tmp;
326 int rv;
327
328 rv = kstrtoll(s, base, &tmp);
329 if (rv < 0)
330 return rv;
331 if (tmp != (s8)tmp)
332 return -ERANGE;
333 *res = tmp;
334 return 0;
335}
336EXPORT_SYMBOL(kstrtos8);
337
338/**
339 * kstrtobool - convert common user inputs into boolean values
340 * @s: input string
341 * @res: result
342 *
343 * This routine returns 0 iff the first character is one of 'YyTt1NnFf0', or
344 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
345 * pointed to by res is updated upon finding a match.
346 */
347noinline
348int kstrtobool(const char *s, bool *res)
349{
350 if (!s)
351 return -EINVAL;
352
353 switch (s[0]) {
354 case 'e':
355 case 'E':
356 case 'y':
357 case 'Y':
358 case 't':
359 case 'T':
360 case '1':
361 *res = true;
362 return 0;
363 case 'd':
364 case 'D':
365 case 'n':
366 case 'N':
367 case 'f':
368 case 'F':
369 case '0':
370 *res = false;
371 return 0;
372 case 'o':
373 case 'O':
374 switch (s[1]) {
375 case 'n':
376 case 'N':
377 *res = true;
378 return 0;
379 case 'f':
380 case 'F':
381 *res = false;
382 return 0;
383 default:
384 break;
385 }
386 break;
387 default:
388 break;
389 }
390
391 return -EINVAL;
392}
393EXPORT_SYMBOL(kstrtobool);
394
395/*
396 * Since "base" would be a nonsense argument, this open-codes the
397 * _from_user helper instead of using the helper macro below.
398 */
399int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
400{
401 /* Longest string needed to differentiate, newline, terminator */
402 char buf[4];
403
404 count = min(count, sizeof(buf) - 1);
405 if (copy_from_user(to: buf, from: s, n: count))
406 return -EFAULT;
407 buf[count] = '\0';
408 return kstrtobool(buf, res);
409}
410EXPORT_SYMBOL(kstrtobool_from_user);
411
412#define kstrto_from_user(f, g, type) \
413int f(const char __user *s, size_t count, unsigned int base, type *res) \
414{ \
415 /* sign, base 2 representation, newline, terminator */ \
416 char buf[1 + sizeof(type) * 8 + 1 + 1]; \
417 \
418 count = min(count, sizeof(buf) - 1); \
419 if (copy_from_user(buf, s, count)) \
420 return -EFAULT; \
421 buf[count] = '\0'; \
422 return g(buf, base, res); \
423} \
424EXPORT_SYMBOL(f)
425
426kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
427kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
428kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
429kstrto_from_user(kstrtol_from_user, kstrtol, long);
430kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
431kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
432kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
433kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
434kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
435kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
436