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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);
v4.10.11
 
  1/*
  2 * Convert integer string representation to an integer.
  3 * If an integer doesn't fit into specified type, -E is returned.
  4 *
  5 * Integer starts with optional sign.
  6 * kstrtou*() functions do not accept sign "-".
  7 *
  8 * Radix 0 means autodetection: leading "0x" implies radix 16,
  9 * leading "0" implies radix 8, otherwise radix is 10.
 10 * Autodetection hints work after optional sign, but not before.
 11 *
 12 * If -E is returned, result is not touched.
 13 */
 14#include <linux/ctype.h>
 15#include <linux/errno.h>
 16#include <linux/kernel.h>
 
 17#include <linux/math64.h>
 18#include <linux/export.h>
 19#include <linux/types.h>
 20#include <linux/uaccess.h>
 
 21#include "kstrtox.h"
 22
 23const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
 24{
 25	if (*base == 0) {
 26		if (s[0] == '0') {
 27			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
 28				*base = 16;
 29			else
 30				*base = 8;
 31		} else
 32			*base = 10;
 33	}
 34	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
 35		s += 2;
 36	return s;
 37}
 38
 39/*
 40 * Convert non-negative integer string representation in explicitly given radix
 41 * to an integer.
 
 42 * Return number of characters consumed maybe or-ed with overflow bit.
 43 * If overflow occurs, result integer (incorrect) is still returned.
 44 *
 45 * Don't you dare use this function.
 46 */
 47unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
 
 48{
 49	unsigned long long res;
 50	unsigned int rv;
 51
 52	res = 0;
 53	rv = 0;
 54	while (*s) {
 
 
 55		unsigned int val;
 56
 57		if ('0' <= *s && *s <= '9')
 58			val = *s - '0';
 59		else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
 60			val = _tolower(*s) - 'a' + 10;
 61		else
 62			break;
 63
 64		if (val >= base)
 65			break;
 66		/*
 67		 * Check for overflow only if we are within range of
 68		 * it in the max base we support (16)
 69		 */
 70		if (unlikely(res & (~0ull << 60))) {
 71			if (res > div_u64(ULLONG_MAX - val, base))
 72				rv |= KSTRTOX_OVERFLOW;
 73		}
 74		res = res * base + val;
 75		rv++;
 76		s++;
 77	}
 78	*p = res;
 79	return rv;
 80}
 81
 
 
 
 
 
 82static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 83{
 84	unsigned long long _res;
 85	unsigned int rv;
 86
 87	s = _parse_integer_fixup_radix(s, &base);
 88	rv = _parse_integer(s, base, &_res);
 89	if (rv & KSTRTOX_OVERFLOW)
 90		return -ERANGE;
 91	if (rv == 0)
 92		return -EINVAL;
 93	s += rv;
 94	if (*s == '\n')
 95		s++;
 96	if (*s)
 97		return -EINVAL;
 98	*res = _res;
 99	return 0;
100}
101
102/**
103 * kstrtoull - convert a string to an unsigned long long
104 * @s: The start of the string. The string must be null-terminated, and may also
105 *  include a single newline before its terminating null. The first character
106 *  may also be a plus sign, but not a minus sign.
107 * @base: The number base to use. The maximum supported base is 16. If base is
108 *  given as 0, then the base of the string is automatically detected with the
109 *  conventional semantics - If it begins with 0x the number will be parsed as a
110 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
111 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
112 * @res: Where to write the result of the conversion on success.
113 *
114 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
115 * Used as a replacement for the obsolete simple_strtoull. Return code must
116 * be checked.
117 */
118int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
119{
120	if (s[0] == '+')
121		s++;
122	return _kstrtoull(s, base, res);
123}
124EXPORT_SYMBOL(kstrtoull);
125
126/**
127 * kstrtoll - convert a string to a long long
128 * @s: The start of the string. The string must be null-terminated, and may also
129 *  include a single newline before its terminating null. The first character
130 *  may also be a plus sign or a minus sign.
131 * @base: The number base to use. The maximum supported base is 16. If base is
132 *  given as 0, then the base of the string is automatically detected with the
133 *  conventional semantics - If it begins with 0x the number will be parsed as a
134 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
135 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
136 * @res: Where to write the result of the conversion on success.
137 *
138 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
139 * Used as a replacement for the obsolete simple_strtoull. Return code must
140 * be checked.
141 */
142int kstrtoll(const char *s, unsigned int base, long long *res)
143{
144	unsigned long long tmp;
145	int rv;
146
147	if (s[0] == '-') {
148		rv = _kstrtoull(s + 1, base, &tmp);
149		if (rv < 0)
150			return rv;
151		if ((long long)-tmp > 0)
152			return -ERANGE;
153		*res = -tmp;
154	} else {
155		rv = kstrtoull(s, base, &tmp);
156		if (rv < 0)
157			return rv;
158		if ((long long)tmp < 0)
159			return -ERANGE;
160		*res = tmp;
161	}
162	return 0;
163}
164EXPORT_SYMBOL(kstrtoll);
165
166/* Internal, do not use. */
167int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
168{
169	unsigned long long tmp;
170	int rv;
171
172	rv = kstrtoull(s, base, &tmp);
173	if (rv < 0)
174		return rv;
175	if (tmp != (unsigned long long)(unsigned long)tmp)
176		return -ERANGE;
177	*res = tmp;
178	return 0;
179}
180EXPORT_SYMBOL(_kstrtoul);
181
182/* Internal, do not use. */
183int _kstrtol(const char *s, unsigned int base, long *res)
184{
185	long long tmp;
186	int rv;
187
188	rv = kstrtoll(s, base, &tmp);
189	if (rv < 0)
190		return rv;
191	if (tmp != (long long)(long)tmp)
192		return -ERANGE;
193	*res = tmp;
194	return 0;
195}
196EXPORT_SYMBOL(_kstrtol);
197
198/**
199 * kstrtouint - convert a string to an unsigned int
200 * @s: The start of the string. The string must be null-terminated, and may also
201 *  include a single newline before its terminating null. The first character
202 *  may also be a plus sign, but not a minus sign.
203 * @base: The number base to use. The maximum supported base is 16. If base is
204 *  given as 0, then the base of the string is automatically detected with the
205 *  conventional semantics - If it begins with 0x the number will be parsed as a
206 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
207 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
208 * @res: Where to write the result of the conversion on success.
209 *
210 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
211 * Used as a replacement for the obsolete simple_strtoull. Return code must
212 * be checked.
213 */
214int 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 long long)(unsigned int)tmp)
223		return -ERANGE;
224	*res = tmp;
225	return 0;
226}
227EXPORT_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 * Used as a replacement for the obsolete simple_strtoull. Return code must
243 * be checked.
244 */
245int kstrtoint(const char *s, unsigned int base, int *res)
246{
247	long long tmp;
248	int rv;
249
250	rv = kstrtoll(s, base, &tmp);
251	if (rv < 0)
252		return rv;
253	if (tmp != (long long)(int)tmp)
254		return -ERANGE;
255	*res = tmp;
256	return 0;
257}
258EXPORT_SYMBOL(kstrtoint);
259
260int kstrtou16(const char *s, unsigned int base, u16 *res)
261{
262	unsigned long long tmp;
263	int rv;
264
265	rv = kstrtoull(s, base, &tmp);
266	if (rv < 0)
267		return rv;
268	if (tmp != (unsigned long long)(u16)tmp)
269		return -ERANGE;
270	*res = tmp;
271	return 0;
272}
273EXPORT_SYMBOL(kstrtou16);
274
275int kstrtos16(const char *s, unsigned int base, s16 *res)
276{
277	long long tmp;
278	int rv;
279
280	rv = kstrtoll(s, base, &tmp);
281	if (rv < 0)
282		return rv;
283	if (tmp != (long long)(s16)tmp)
284		return -ERANGE;
285	*res = tmp;
286	return 0;
287}
288EXPORT_SYMBOL(kstrtos16);
289
290int kstrtou8(const char *s, unsigned int base, u8 *res)
291{
292	unsigned long long tmp;
293	int rv;
294
295	rv = kstrtoull(s, base, &tmp);
296	if (rv < 0)
297		return rv;
298	if (tmp != (unsigned long long)(u8)tmp)
299		return -ERANGE;
300	*res = tmp;
301	return 0;
302}
303EXPORT_SYMBOL(kstrtou8);
304
305int kstrtos8(const char *s, unsigned int base, s8 *res)
306{
307	long long tmp;
308	int rv;
309
310	rv = kstrtoll(s, base, &tmp);
311	if (rv < 0)
312		return rv;
313	if (tmp != (long long)(s8)tmp)
314		return -ERANGE;
315	*res = tmp;
316	return 0;
317}
318EXPORT_SYMBOL(kstrtos8);
319
320/**
321 * kstrtobool - convert common user inputs into boolean values
322 * @s: input string
323 * @res: result
324 *
325 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
326 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
327 * pointed to by res is updated upon finding a match.
328 */
329int kstrtobool(const char *s, bool *res)
330{
331	if (!s)
332		return -EINVAL;
333
334	switch (s[0]) {
335	case 'y':
336	case 'Y':
337	case '1':
338		*res = true;
339		return 0;
340	case 'n':
341	case 'N':
342	case '0':
343		*res = false;
344		return 0;
345	case 'o':
346	case 'O':
347		switch (s[1]) {
348		case 'n':
349		case 'N':
350			*res = true;
351			return 0;
352		case 'f':
353		case 'F':
354			*res = false;
355			return 0;
356		default:
357			break;
358		}
 
359	default:
360		break;
361	}
362
363	return -EINVAL;
364}
365EXPORT_SYMBOL(kstrtobool);
366
367/*
368 * Since "base" would be a nonsense argument, this open-codes the
369 * _from_user helper instead of using the helper macro below.
370 */
371int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
372{
373	/* Longest string needed to differentiate, newline, terminator */
374	char buf[4];
375
376	count = min(count, sizeof(buf) - 1);
377	if (copy_from_user(buf, s, count))
378		return -EFAULT;
379	buf[count] = '\0';
380	return kstrtobool(buf, res);
381}
382EXPORT_SYMBOL(kstrtobool_from_user);
383
384#define kstrto_from_user(f, g, type)					\
385int f(const char __user *s, size_t count, unsigned int base, type *res)	\
386{									\
387	/* sign, base 2 representation, newline, terminator */		\
388	char buf[1 + sizeof(type) * 8 + 1 + 1];				\
389									\
390	count = min(count, sizeof(buf) - 1);				\
391	if (copy_from_user(buf, s, count))				\
392		return -EFAULT;						\
393	buf[count] = '\0';						\
394	return g(buf, base, res);					\
395}									\
396EXPORT_SYMBOL(f)
397
398kstrto_from_user(kstrtoull_from_user,	kstrtoull,	unsigned long long);
399kstrto_from_user(kstrtoll_from_user,	kstrtoll,	long long);
400kstrto_from_user(kstrtoul_from_user,	kstrtoul,	unsigned long);
401kstrto_from_user(kstrtol_from_user,	kstrtol,	long);
402kstrto_from_user(kstrtouint_from_user,	kstrtouint,	unsigned int);
403kstrto_from_user(kstrtoint_from_user,	kstrtoint,	int);
404kstrto_from_user(kstrtou16_from_user,	kstrtou16,	u16);
405kstrto_from_user(kstrtos16_from_user,	kstrtos16,	s16);
406kstrto_from_user(kstrtou8_from_user,	kstrtou8,	u8);
407kstrto_from_user(kstrtos8_from_user,	kstrtos8,	s8);