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