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