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b2441318 1// SPDX-License-Identifier: GPL-2.0
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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/kernel.h>
18#include <linux/math64.h>
8bc3bcc9 19#include <linux/export.h>
33ee3b2e 20#include <linux/types.h>
7c0f6ba6 21#include <linux/uaccess.h>
1dff46d6 22#include "kstrtox.h"
33ee3b2e 23
1dff46d6 24const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
33ee3b2e 25{
1dff46d6 26 if (*base == 0) {
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27 if (s[0] == '0') {
28 if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
1dff46d6 29 *base = 16;
33ee3b2e 30 else
1dff46d6 31 *base = 8;
33ee3b2e 32 } else
1dff46d6 33 *base = 10;
33ee3b2e 34 }
1dff46d6 35 if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
33ee3b2e 36 s += 2;
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37 return s;
38}
39
40/*
41 * Convert non-negative integer string representation in explicitly given radix
42 * to an integer.
43 * Return number of characters consumed maybe or-ed with overflow bit.
44 * If overflow occurs, result integer (incorrect) is still returned.
45 *
46 * Don't you dare use this function.
47 */
690d137f 48unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
1dff46d6 49{
690d137f 50 unsigned long long res;
1dff46d6 51 unsigned int rv;
33ee3b2e 52
690d137f 53 res = 0;
1dff46d6 54 rv = 0;
512750ef 55 while (1) {
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56 unsigned int c = *s;
57 unsigned int lc = c | 0x20; /* don't tolower() this line */
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58 unsigned int val;
59
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60 if ('0' <= c && c <= '9')
61 val = c - '0';
62 else if ('a' <= lc && lc <= 'f')
63 val = lc - 'a' + 10;
78be959e 64 else
1dff46d6 65 break;
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66
67 if (val >= base)
1dff46d6 68 break;
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69 /*
70 * Check for overflow only if we are within range of
71 * it in the max base we support (16)
72 */
73 if (unlikely(res & (~0ull << 60))) {
74 if (res > div_u64(ULLONG_MAX - val, base))
8cfd56d4 75 rv |= KSTRTOX_OVERFLOW;
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DH
76 }
77 res = res * base + val;
1dff46d6 78 rv++;
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79 s++;
80 }
690d137f 81 *p = res;
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82 return rv;
83}
84
85static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
86{
87 unsigned long long _res;
88 unsigned int rv;
89
90 s = _parse_integer_fixup_radix(s, &base);
91 rv = _parse_integer(s, base, &_res);
92 if (rv & KSTRTOX_OVERFLOW)
93 return -ERANGE;
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94 if (rv == 0)
95 return -EINVAL;
96 s += rv;
97 if (*s == '\n')
98 s++;
99 if (*s)
33ee3b2e 100 return -EINVAL;
1dff46d6 101 *res = _res;
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102 return 0;
103}
104
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105/**
106 * kstrtoull - convert a string to an unsigned long long
107 * @s: The start of the string. The string must be null-terminated, and may also
108 * include a single newline before its terminating null. The first character
109 * may also be a plus sign, but not a minus sign.
110 * @base: The number base to use. The maximum supported base is 16. If base is
111 * given as 0, then the base of the string is automatically detected with the
112 * conventional semantics - If it begins with 0x the number will be parsed as a
113 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
114 * parsed as an octal number. Otherwise it will be parsed as a decimal.
115 * @res: Where to write the result of the conversion on success.
116 *
117 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
ef0f2685 118 * Preferred over simple_strtoull(). Return code must be checked.
4c925d60 119 */
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120int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
121{
122 if (s[0] == '+')
123 s++;
124 return _kstrtoull(s, base, res);
125}
126EXPORT_SYMBOL(kstrtoull);
127
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128/**
129 * kstrtoll - convert a string to a long long
130 * @s: The start of the string. The string must be null-terminated, and may also
131 * include a single newline before its terminating null. The first character
132 * may also be a plus sign or a minus sign.
133 * @base: The number base to use. The maximum supported base is 16. If base is
134 * given as 0, then the base of the string is automatically detected with the
135 * conventional semantics - If it begins with 0x the number will be parsed as a
136 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
137 * parsed as an octal number. Otherwise it will be parsed as a decimal.
138 * @res: Where to write the result of the conversion on success.
139 *
140 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
ef0f2685 141 * Preferred over simple_strtoll(). Return code must be checked.
4c925d60 142 */
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143int kstrtoll(const char *s, unsigned int base, long long *res)
144{
145 unsigned long long tmp;
146 int rv;
147
148 if (s[0] == '-') {
149 rv = _kstrtoull(s + 1, base, &tmp);
150 if (rv < 0)
151 return rv;
2d2e4715 152 if ((long long)-tmp > 0)
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153 return -ERANGE;
154 *res = -tmp;
155 } else {
156 rv = kstrtoull(s, base, &tmp);
157 if (rv < 0)
158 return rv;
159 if ((long long)tmp < 0)
160 return -ERANGE;
161 *res = tmp;
162 }
163 return 0;
164}
165EXPORT_SYMBOL(kstrtoll);
166
167/* Internal, do not use. */
168int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
169{
170 unsigned long long tmp;
171 int rv;
172
173 rv = kstrtoull(s, base, &tmp);
174 if (rv < 0)
175 return rv;
048e513d 176 if (tmp != (unsigned long)tmp)
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177 return -ERANGE;
178 *res = tmp;
179 return 0;
180}
181EXPORT_SYMBOL(_kstrtoul);
182
183/* Internal, do not use. */
184int _kstrtol(const char *s, unsigned int base, long *res)
185{
186 long long tmp;
187 int rv;
188
189 rv = kstrtoll(s, base, &tmp);
190 if (rv < 0)
191 return rv;
048e513d 192 if (tmp != (long)tmp)
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193 return -ERANGE;
194 *res = tmp;
195 return 0;
196}
197EXPORT_SYMBOL(_kstrtol);
198
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199/**
200 * kstrtouint - convert a string to an unsigned int
201 * @s: The start of the string. The string must be null-terminated, and may also
202 * include a single newline before its terminating null. The first character
203 * may also be a plus sign, but not a minus sign.
204 * @base: The number base to use. The maximum supported base is 16. If base is
205 * given as 0, then the base of the string is automatically detected with the
206 * conventional semantics - If it begins with 0x the number will be parsed as a
207 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
208 * parsed as an octal number. Otherwise it will be parsed as a decimal.
209 * @res: Where to write the result of the conversion on success.
210 *
211 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
ef0f2685 212 * Preferred over simple_strtoul(). Return code must be checked.
4c925d60 213 */
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214int kstrtouint(const char *s, unsigned int base, unsigned int *res)
215{
216 unsigned long long tmp;
217 int rv;
218
219 rv = kstrtoull(s, base, &tmp);
220 if (rv < 0)
221 return rv;
048e513d 222 if (tmp != (unsigned int)tmp)
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223 return -ERANGE;
224 *res = tmp;
225 return 0;
226}
227EXPORT_SYMBOL(kstrtouint);
228
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229/**
230 * kstrtoint - convert a string to an int
231 * @s: The start of the string. The string must be null-terminated, and may also
232 * include a single newline before its terminating null. The first character
233 * may also be a plus sign or a minus sign.
234 * @base: The number base to use. The maximum supported base is 16. If base is
235 * given as 0, then the base of the string is automatically detected with the
236 * conventional semantics - If it begins with 0x the number will be parsed as a
237 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
238 * parsed as an octal number. Otherwise it will be parsed as a decimal.
239 * @res: Where to write the result of the conversion on success.
240 *
241 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
ef0f2685 242 * Preferred over simple_strtol(). Return code must be checked.
4c925d60 243 */
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244int kstrtoint(const char *s, unsigned int base, int *res)
245{
246 long long tmp;
247 int rv;
248
249 rv = kstrtoll(s, base, &tmp);
250 if (rv < 0)
251 return rv;
048e513d 252 if (tmp != (int)tmp)
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253 return -ERANGE;
254 *res = tmp;
255 return 0;
256}
257EXPORT_SYMBOL(kstrtoint);
258
259int kstrtou16(const char *s, unsigned int base, u16 *res)
260{
261 unsigned long long tmp;
262 int rv;
263
264 rv = kstrtoull(s, base, &tmp);
265 if (rv < 0)
266 return rv;
048e513d 267 if (tmp != (u16)tmp)
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268 return -ERANGE;
269 *res = tmp;
270 return 0;
271}
272EXPORT_SYMBOL(kstrtou16);
273
274int kstrtos16(const char *s, unsigned int base, s16 *res)
275{
276 long long tmp;
277 int rv;
278
279 rv = kstrtoll(s, base, &tmp);
280 if (rv < 0)
281 return rv;
048e513d 282 if (tmp != (s16)tmp)
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283 return -ERANGE;
284 *res = tmp;
285 return 0;
286}
287EXPORT_SYMBOL(kstrtos16);
288
289int kstrtou8(const char *s, unsigned int base, u8 *res)
290{
291 unsigned long long tmp;
292 int rv;
293
294 rv = kstrtoull(s, base, &tmp);
295 if (rv < 0)
296 return rv;
048e513d 297 if (tmp != (u8)tmp)
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298 return -ERANGE;
299 *res = tmp;
300 return 0;
301}
302EXPORT_SYMBOL(kstrtou8);
303
304int kstrtos8(const char *s, unsigned int base, s8 *res)
305{
306 long long tmp;
307 int rv;
308
309 rv = kstrtoll(s, base, &tmp);
310 if (rv < 0)
311 return rv;
048e513d 312 if (tmp != (s8)tmp)
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313 return -ERANGE;
314 *res = tmp;
315 return 0;
316}
317EXPORT_SYMBOL(kstrtos8);
c196e32a 318
ef951599
KC
319/**
320 * kstrtobool - convert common user inputs into boolean values
321 * @s: input string
322 * @res: result
323 *
a81a5a17
KC
324 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
325 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
326 * pointed to by res is updated upon finding a match.
ef951599
KC
327 */
328int kstrtobool(const char *s, bool *res)
329{
330 if (!s)
331 return -EINVAL;
332
333 switch (s[0]) {
334 case 'y':
335 case 'Y':
336 case '1':
337 *res = true;
338 return 0;
339 case 'n':
340 case 'N':
341 case '0':
342 *res = false;
343 return 0;
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344 case 'o':
345 case 'O':
346 switch (s[1]) {
347 case 'n':
348 case 'N':
349 *res = true;
350 return 0;
351 case 'f':
352 case 'F':
353 *res = false;
354 return 0;
355 default:
356 break;
357 }
ef951599
KC
358 default:
359 break;
360 }
361
362 return -EINVAL;
363}
364EXPORT_SYMBOL(kstrtobool);
365
366/*
367 * Since "base" would be a nonsense argument, this open-codes the
368 * _from_user helper instead of using the helper macro below.
369 */
370int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
371{
372 /* Longest string needed to differentiate, newline, terminator */
373 char buf[4];
374
375 count = min(count, sizeof(buf) - 1);
376 if (copy_from_user(buf, s, count))
377 return -EFAULT;
378 buf[count] = '\0';
379 return kstrtobool(buf, res);
380}
381EXPORT_SYMBOL(kstrtobool_from_user);
382
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383#define kstrto_from_user(f, g, type) \
384int f(const char __user *s, size_t count, unsigned int base, type *res) \
385{ \
386 /* sign, base 2 representation, newline, terminator */ \
387 char buf[1 + sizeof(type) * 8 + 1 + 1]; \
388 \
389 count = min(count, sizeof(buf) - 1); \
390 if (copy_from_user(buf, s, count)) \
391 return -EFAULT; \
392 buf[count] = '\0'; \
393 return g(buf, base, res); \
394} \
395EXPORT_SYMBOL(f)
396
397kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
398kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
399kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
400kstrto_from_user(kstrtol_from_user, kstrtol, long);
401kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
402kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
403kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
404kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
405kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
406kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);