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v5.14.15
  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
 25const 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 */
 50unsigned 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
 88unsigned 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
 93static 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 */
128int 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}
134EXPORT_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 */
151int 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}
173EXPORT_SYMBOL(kstrtoll);
174
175/* Internal, do not use. */
176int _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}
189EXPORT_SYMBOL(_kstrtoul);
190
191/* Internal, do not use. */
192int _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}
205EXPORT_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 */
222int 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}
235EXPORT_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 */
252int 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}
265EXPORT_SYMBOL(kstrtoint);
266
267int 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}
280EXPORT_SYMBOL(kstrtou16);
281
282int 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}
295EXPORT_SYMBOL(kstrtos16);
296
297int 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}
310EXPORT_SYMBOL(kstrtou8);
311
312int 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}
325EXPORT_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 */
336int 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}
373EXPORT_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 */
379int 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}
390EXPORT_SYMBOL(kstrtobool_from_user);
391
392#define kstrto_from_user(f, g, type)					\
393int 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}									\
404EXPORT_SYMBOL(f)
405
406kstrto_from_user(kstrtoull_from_user,	kstrtoull,	unsigned long long);
407kstrto_from_user(kstrtoll_from_user,	kstrtoll,	long long);
408kstrto_from_user(kstrtoul_from_user,	kstrtoul,	unsigned long);
409kstrto_from_user(kstrtol_from_user,	kstrtol,	long);
410kstrto_from_user(kstrtouint_from_user,	kstrtouint,	unsigned int);
411kstrto_from_user(kstrtoint_from_user,	kstrtoint,	int);
412kstrto_from_user(kstrtou16_from_user,	kstrtou16,	u16);
413kstrto_from_user(kstrtos16_from_user,	kstrtos16,	s16);
414kstrto_from_user(kstrtou8_from_user,	kstrtou8,	u8);
415kstrto_from_user(kstrtos8_from_user,	kstrtos8,	s8);
v5.4
  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
 24const 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 */
 48unsigned 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
 
 
 
 
 
 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;
 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 */
121int 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}
127EXPORT_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 */
145int 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}
167EXPORT_SYMBOL(kstrtoll);
168
169/* Internal, do not use. */
170int _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}
183EXPORT_SYMBOL(_kstrtoul);
184
185/* Internal, do not use. */
186int _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}
199EXPORT_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 */
217int 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}
230EXPORT_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 */
248int 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}
261EXPORT_SYMBOL(kstrtoint);
262
263int 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}
276EXPORT_SYMBOL(kstrtou16);
277
278int 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}
291EXPORT_SYMBOL(kstrtos16);
292
293int 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}
306EXPORT_SYMBOL(kstrtou8);
307
308int 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}
321EXPORT_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 */
332int 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}
368EXPORT_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 */
374int 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}
385EXPORT_SYMBOL(kstrtobool_from_user);
386
387#define kstrto_from_user(f, g, type)					\
388int 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}									\
399EXPORT_SYMBOL(f)
400
401kstrto_from_user(kstrtoull_from_user,	kstrtoull,	unsigned long long);
402kstrto_from_user(kstrtoll_from_user,	kstrtoll,	long long);
403kstrto_from_user(kstrtoul_from_user,	kstrtoul,	unsigned long);
404kstrto_from_user(kstrtol_from_user,	kstrtol,	long);
405kstrto_from_user(kstrtouint_from_user,	kstrtouint,	unsigned int);
406kstrto_from_user(kstrtoint_from_user,	kstrtoint,	int);
407kstrto_from_user(kstrtou16_from_user,	kstrtou16,	u16);
408kstrto_from_user(kstrtos16_from_user,	kstrtos16,	s16);
409kstrto_from_user(kstrtou8_from_user,	kstrtou8,	u8);
410kstrto_from_user(kstrtos8_from_user,	kstrtos8,	s8);