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.
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 */
_parse_integer(const char * s,unsigned int base,unsigned long long * p)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
_kstrtoull(const char * s,unsigned int base,unsigned long long * res)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 * Preferred over simple_strtoull(). Return code must be checked.
119 */
kstrtoull(const char * s,unsigned int base,unsigned long long * res)120 int 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 }
126 EXPORT_SYMBOL(kstrtoull);
127
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.
141 * Preferred over simple_strtoll(). Return code must be checked.
142 */
kstrtoll(const char * s,unsigned int base,long long * res)143 int 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;
152 if ((long long)-tmp > 0)
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 }
165 EXPORT_SYMBOL(kstrtoll);
166
167 /* Internal, do not use. */
_kstrtoul(const char * s,unsigned int base,unsigned long * res)168 int _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;
176 if (tmp != (unsigned long)tmp)
177 return -ERANGE;
178 *res = tmp;
179 return 0;
180 }
181 EXPORT_SYMBOL(_kstrtoul);
182
183 /* Internal, do not use. */
_kstrtol(const char * s,unsigned int base,long * res)184 int _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;
192 if (tmp != (long)tmp)
193 return -ERANGE;
194 *res = tmp;
195 return 0;
196 }
197 EXPORT_SYMBOL(_kstrtol);
198
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.
212 * Preferred over simple_strtoul(). Return code must be checked.
213 */
kstrtouint(const char * s,unsigned int base,unsigned int * res)214 int 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;
222 if (tmp != (unsigned int)tmp)
223 return -ERANGE;
224 *res = tmp;
225 return 0;
226 }
227 EXPORT_SYMBOL(kstrtouint);
228
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.
242 * Preferred over simple_strtol(). Return code must be checked.
243 */
kstrtoint(const char * s,unsigned int base,int * res)244 int 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;
252 if (tmp != (int)tmp)
253 return -ERANGE;
254 *res = tmp;
255 return 0;
256 }
257 EXPORT_SYMBOL(kstrtoint);
258
kstrtou16(const char * s,unsigned int base,u16 * res)259 int 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;
267 if (tmp != (u16)tmp)
268 return -ERANGE;
269 *res = tmp;
270 return 0;
271 }
272 EXPORT_SYMBOL(kstrtou16);
273
kstrtos16(const char * s,unsigned int base,s16 * res)274 int 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;
282 if (tmp != (s16)tmp)
283 return -ERANGE;
284 *res = tmp;
285 return 0;
286 }
287 EXPORT_SYMBOL(kstrtos16);
288
kstrtou8(const char * s,unsigned int base,u8 * res)289 int 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;
297 if (tmp != (u8)tmp)
298 return -ERANGE;
299 *res = tmp;
300 return 0;
301 }
302 EXPORT_SYMBOL(kstrtou8);
303
kstrtos8(const char * s,unsigned int base,s8 * res)304 int 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;
312 if (tmp != (s8)tmp)
313 return -ERANGE;
314 *res = tmp;
315 return 0;
316 }
317 EXPORT_SYMBOL(kstrtos8);
318
319 /**
320 * kstrtobool - convert common user inputs into boolean values
321 * @s: input string
322 * @res: result
323 *
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.
327 */
kstrtobool(const char * s,bool * res)328 int 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;
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 }
358 default:
359 break;
360 }
361
362 return -EINVAL;
363 }
364 EXPORT_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 */
kstrtobool_from_user(const char __user * s,size_t count,bool * res)370 int 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 }
381 EXPORT_SYMBOL(kstrtobool_from_user);
382
383 #define kstrto_from_user(f, g, type) \
384 int 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 } \
395 EXPORT_SYMBOL(f)
396
397 kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
398 kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
399 kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
400 kstrto_from_user(kstrtol_from_user, kstrtol, long);
401 kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
402 kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
403 kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
404 kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
405 kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
406 kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
407
