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
_parse_integer_fixup_radix(const char * s,unsigned int * base)25 const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
26 {
27 if (*base == 0) {
28 if (s[0] == '0') {
29 if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
30 *base = 16;
31 else
32 *base = 8;
33 } else
34 *base = 10;
35 }
36 if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
37 s += 2;
38 return s;
39 }
40
41 /*
42 * Convert non-negative integer string representation in explicitly given radix
43 * to an integer. A maximum of max_chars characters will be converted.
44 *
45 * Return number of characters consumed maybe or-ed with overflow bit.
46 * If overflow occurs, result integer (incorrect) is still returned.
47 *
48 * Don't you dare use this function.
49 */
_parse_integer_limit(const char * s,unsigned int base,unsigned long long * p,size_t max_chars)50 unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
51 size_t max_chars)
52 {
53 unsigned long long res;
54 unsigned int rv;
55
56 res = 0;
57 rv = 0;
58 while (max_chars--) {
59 unsigned int c = *s;
60 unsigned int lc = c | 0x20; /* don't tolower() this line */
61 unsigned int val;
62
63 if ('0' <= c && c <= '9')
64 val = c - '0';
65 else if ('a' <= lc && lc <= 'f')
66 val = lc - 'a' + 10;
67 else
68 break;
69
70 if (val >= base)
71 break;
72 /*
73 * Check for overflow only if we are within range of
74 * it in the max base we support (16)
75 */
76 if (unlikely(res & (~0ull << 60))) {
77 if (res > div_u64(ULLONG_MAX - val, base))
78 rv |= KSTRTOX_OVERFLOW;
79 }
80 res = res * base + val;
81 rv++;
82 s++;
83 }
84 *p = res;
85 return rv;
86 }
87
_parse_integer(const char * s,unsigned int base,unsigned long long * p)88 unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
89 {
90 return _parse_integer_limit(s, base, p, INT_MAX);
91 }
92
_kstrtoull(const char * s,unsigned int base,unsigned long long * res)93 static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
94 {
95 unsigned long long _res;
96 unsigned int rv;
97
98 s = _parse_integer_fixup_radix(s, &base);
99 rv = _parse_integer(s, base, &_res);
100 if (rv & KSTRTOX_OVERFLOW)
101 return -ERANGE;
102 if (rv == 0)
103 return -EINVAL;
104 s += rv;
105 if (*s == '\n')
106 s++;
107 if (*s)
108 return -EINVAL;
109 *res = _res;
110 return 0;
111 }
112
113 /**
114 * kstrtoull - convert a string to an unsigned long long
115 * @s: The start of the string. The string must be null-terminated, and may also
116 * include a single newline before its terminating null. The first character
117 * may also be a plus sign, but not a minus sign.
118 * @base: The number base to use. The maximum supported base is 16. If base is
119 * given as 0, then the base of the string is automatically detected with the
120 * conventional semantics - If it begins with 0x the number will be parsed as a
121 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
122 * parsed as an octal number. Otherwise it will be parsed as a decimal.
123 * @res: Where to write the result of the conversion on success.
124 *
125 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
126 * Preferred over simple_strtoull(). Return code must be checked.
127 */
kstrtoull(const char * s,unsigned int base,unsigned long long * res)128 int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
129 {
130 if (s[0] == '+')
131 s++;
132 return _kstrtoull(s, base, res);
133 }
134 EXPORT_SYMBOL(kstrtoull);
135
136 /**
137 * kstrtoll - convert a string to a long long
138 * @s: The start of the string. The string must be null-terminated, and may also
139 * include a single newline before its terminating null. The first character
140 * may also be a plus sign or a minus sign.
141 * @base: The number base to use. The maximum supported base is 16. If base is
142 * given as 0, then the base of the string is automatically detected with the
143 * conventional semantics - If it begins with 0x the number will be parsed as a
144 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
145 * parsed as an octal number. Otherwise it will be parsed as a decimal.
146 * @res: Where to write the result of the conversion on success.
147 *
148 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
149 * Preferred over simple_strtoll(). Return code must be checked.
150 */
kstrtoll(const char * s,unsigned int base,long long * res)151 int kstrtoll(const char *s, unsigned int base, long long *res)
152 {
153 unsigned long long tmp;
154 int rv;
155
156 if (s[0] == '-') {
157 rv = _kstrtoull(s + 1, base, &tmp);
158 if (rv < 0)
159 return rv;
160 if ((long long)-tmp > 0)
161 return -ERANGE;
162 *res = -tmp;
163 } else {
164 rv = kstrtoull(s, base, &tmp);
165 if (rv < 0)
166 return rv;
167 if ((long long)tmp < 0)
168 return -ERANGE;
169 *res = tmp;
170 }
171 return 0;
172 }
173 EXPORT_SYMBOL(kstrtoll);
174
175 /* Internal, do not use. */
_kstrtoul(const char * s,unsigned int base,unsigned long * res)176 int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
177 {
178 unsigned long long tmp;
179 int rv;
180
181 rv = kstrtoull(s, base, &tmp);
182 if (rv < 0)
183 return rv;
184 if (tmp != (unsigned long)tmp)
185 return -ERANGE;
186 *res = tmp;
187 return 0;
188 }
189 EXPORT_SYMBOL(_kstrtoul);
190
191 /* Internal, do not use. */
_kstrtol(const char * s,unsigned int base,long * res)192 int _kstrtol(const char *s, unsigned int base, long *res)
193 {
194 long long tmp;
195 int rv;
196
197 rv = kstrtoll(s, base, &tmp);
198 if (rv < 0)
199 return rv;
200 if (tmp != (long)tmp)
201 return -ERANGE;
202 *res = tmp;
203 return 0;
204 }
205 EXPORT_SYMBOL(_kstrtol);
206
207 /**
208 * kstrtouint - convert a string to an unsigned int
209 * @s: The start of the string. The string must be null-terminated, and may also
210 * include a single newline before its terminating null. The first character
211 * may also be a plus sign, but not a minus sign.
212 * @base: The number base to use. The maximum supported base is 16. If base is
213 * given as 0, then the base of the string is automatically detected with the
214 * conventional semantics - If it begins with 0x the number will be parsed as a
215 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
216 * parsed as an octal number. Otherwise it will be parsed as a decimal.
217 * @res: Where to write the result of the conversion on success.
218 *
219 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
220 * Preferred over simple_strtoul(). Return code must be checked.
221 */
kstrtouint(const char * s,unsigned int base,unsigned int * res)222 int kstrtouint(const char *s, unsigned int base, unsigned int *res)
223 {
224 unsigned long long tmp;
225 int rv;
226
227 rv = kstrtoull(s, base, &tmp);
228 if (rv < 0)
229 return rv;
230 if (tmp != (unsigned int)tmp)
231 return -ERANGE;
232 *res = tmp;
233 return 0;
234 }
235 EXPORT_SYMBOL(kstrtouint);
236
237 /**
238 * kstrtoint - convert a string to an int
239 * @s: The start of the string. The string must be null-terminated, and may also
240 * include a single newline before its terminating null. The first character
241 * may also be a plus sign or a minus sign.
242 * @base: The number base to use. The maximum supported base is 16. If base is
243 * given as 0, then the base of the string is automatically detected with the
244 * conventional semantics - If it begins with 0x the number will be parsed as a
245 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
246 * parsed as an octal number. Otherwise it will be parsed as a decimal.
247 * @res: Where to write the result of the conversion on success.
248 *
249 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
250 * Preferred over simple_strtol(). Return code must be checked.
251 */
kstrtoint(const char * s,unsigned int base,int * res)252 int kstrtoint(const char *s, unsigned int base, int *res)
253 {
254 long long tmp;
255 int rv;
256
257 rv = kstrtoll(s, base, &tmp);
258 if (rv < 0)
259 return rv;
260 if (tmp != (int)tmp)
261 return -ERANGE;
262 *res = tmp;
263 return 0;
264 }
265 EXPORT_SYMBOL(kstrtoint);
266
kstrtou16(const char * s,unsigned int base,u16 * res)267 int kstrtou16(const char *s, unsigned int base, u16 *res)
268 {
269 unsigned long long tmp;
270 int rv;
271
272 rv = kstrtoull(s, base, &tmp);
273 if (rv < 0)
274 return rv;
275 if (tmp != (u16)tmp)
276 return -ERANGE;
277 *res = tmp;
278 return 0;
279 }
280 EXPORT_SYMBOL(kstrtou16);
281
kstrtos16(const char * s,unsigned int base,s16 * res)282 int kstrtos16(const char *s, unsigned int base, s16 *res)
283 {
284 long long tmp;
285 int rv;
286
287 rv = kstrtoll(s, base, &tmp);
288 if (rv < 0)
289 return rv;
290 if (tmp != (s16)tmp)
291 return -ERANGE;
292 *res = tmp;
293 return 0;
294 }
295 EXPORT_SYMBOL(kstrtos16);
296
kstrtou8(const char * s,unsigned int base,u8 * res)297 int kstrtou8(const char *s, unsigned int base, u8 *res)
298 {
299 unsigned long long tmp;
300 int rv;
301
302 rv = kstrtoull(s, base, &tmp);
303 if (rv < 0)
304 return rv;
305 if (tmp != (u8)tmp)
306 return -ERANGE;
307 *res = tmp;
308 return 0;
309 }
310 EXPORT_SYMBOL(kstrtou8);
311
kstrtos8(const char * s,unsigned int base,s8 * res)312 int kstrtos8(const char *s, unsigned int base, s8 *res)
313 {
314 long long tmp;
315 int rv;
316
317 rv = kstrtoll(s, base, &tmp);
318 if (rv < 0)
319 return rv;
320 if (tmp != (s8)tmp)
321 return -ERANGE;
322 *res = tmp;
323 return 0;
324 }
325 EXPORT_SYMBOL(kstrtos8);
326
327 /**
328 * kstrtobool - convert common user inputs into boolean values
329 * @s: input string
330 * @res: result
331 *
332 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
333 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
334 * pointed to by res is updated upon finding a match.
335 */
kstrtobool(const char * s,bool * res)336 int kstrtobool(const char *s, bool *res)
337 {
338 if (!s)
339 return -EINVAL;
340
341 switch (s[0]) {
342 case 'y':
343 case 'Y':
344 case '1':
345 *res = true;
346 return 0;
347 case 'n':
348 case 'N':
349 case '0':
350 *res = false;
351 return 0;
352 case 'o':
353 case 'O':
354 switch (s[1]) {
355 case 'n':
356 case 'N':
357 *res = true;
358 return 0;
359 case 'f':
360 case 'F':
361 *res = false;
362 return 0;
363 default:
364 break;
365 }
366 break;
367 default:
368 break;
369 }
370
371 return -EINVAL;
372 }
373 EXPORT_SYMBOL(kstrtobool);
374
375 /*
376 * Since "base" would be a nonsense argument, this open-codes the
377 * _from_user helper instead of using the helper macro below.
378 */
kstrtobool_from_user(const char __user * s,size_t count,bool * res)379 int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
380 {
381 /* Longest string needed to differentiate, newline, terminator */
382 char buf[4];
383
384 count = min(count, sizeof(buf) - 1);
385 if (copy_from_user(buf, s, count))
386 return -EFAULT;
387 buf[count] = '\0';
388 return kstrtobool(buf, res);
389 }
390 EXPORT_SYMBOL(kstrtobool_from_user);
391
392 #define kstrto_from_user(f, g, type) \
393 int f(const char __user *s, size_t count, unsigned int base, type *res) \
394 { \
395 /* sign, base 2 representation, newline, terminator */ \
396 char buf[1 + sizeof(type) * 8 + 1 + 1]; \
397 \
398 count = min(count, sizeof(buf) - 1); \
399 if (copy_from_user(buf, s, count)) \
400 return -EFAULT; \
401 buf[count] = '\0'; \
402 return g(buf, base, res); \
403 } \
404 EXPORT_SYMBOL(f)
405
406 kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
407 kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
408 kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
409 kstrto_from_user(kstrtol_from_user, kstrtol, long);
410 kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
411 kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
412 kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
413 kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
414 kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
415 kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
416