[mirror_ubuntu-jammy-kernel.git] / lib / kstrtox.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Convert integer string representation to an integer.
 * If an integer doesn't fit into specified type, -E is returned.
 *
 * Integer starts with optional sign.
 * kstrtou*() functions do not accept sign "-".
 *
 * Radix 0 means autodetection: leading "0x" implies radix 16,
 * leading "0" implies radix 8, otherwise radix is 10.
 * Autodetection hints work after optional sign, but not before.
 *
 * If -E is returned, result is not touched.
 */
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/kstrtox.h>
#include <linux/math64.h>
#include <linux/types.h>
#include <linux/uaccess.h>

#include "kstrtox.h"

const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
{
	if (*base == 0) {
		if (s[0] == '0') {
			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
				*base = 16;
			else
				*base = 8;
		} else
			*base = 10;
	}
	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
		s += 2;
	return s;
}

/*
 * Convert non-negative integer string representation in explicitly given radix
 * to an integer. A maximum of max_chars characters will be converted.
 *
 * Return number of characters consumed maybe or-ed with overflow bit.
 * If overflow occurs, result integer (incorrect) is still returned.
 *
 * Don't you dare use this function.
 */
unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
				  size_t max_chars)
{
	unsigned long long res;
	unsigned int rv;

	res = 0;
	rv = 0;
	while (max_chars--) {
		unsigned int c = *s;
		unsigned int lc = c | 0x20; /* don't tolower() this line */
		unsigned int val;

		if ('0' <= c && c <= '9')
			val = c - '0';
		else if ('a' <= lc && lc <= 'f')
			val = lc - 'a' + 10;
		else
			break;

		if (val >= base)
			break;
		/*
		 * Check for overflow only if we are within range of
		 * it in the max base we support (16)
		 */
		if (unlikely(res & (~0ull << 60))) {
			if (res > div_u64(ULLONG_MAX - val, base))
				rv |= KSTRTOX_OVERFLOW;
		}
		res = res * base + val;
		rv++;
		s++;
	}
	*p = res;
	return rv;
}

unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
{
	return _parse_integer_limit(s, base, p, INT_MAX);
}

static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
{
	unsigned long long _res;
	unsigned int rv;

	s = _parse_integer_fixup_radix(s, &base);
	rv = _parse_integer(s, base, &_res);
	if (rv & KSTRTOX_OVERFLOW)
		return -ERANGE;
	if (rv == 0)
		return -EINVAL;
	s += rv;
	if (*s == '\n')
		s++;
	if (*s)
		return -EINVAL;
	*res = _res;
	return 0;
}

/**
 * kstrtoull - convert a string to an unsigned long long
 * @s: The start of the string. The string must be null-terminated, and may also
 *  include a single newline before its terminating null. The first character
 *  may also be a plus sign, but not a minus sign.
 * @base: The number base to use. The maximum supported base is 16. If base is
 *  given as 0, then the base of the string is automatically detected with the
 *  conventional semantics - If it begins with 0x the number will be parsed as a
 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 * @res: Where to write the result of the conversion on success.
 *
 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 * Preferred over simple_strtoull(). Return code must be checked.
 */
int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
{
	if (s[0] == '+')
		s++;
	return _kstrtoull(s, base, res);
}
EXPORT_SYMBOL(kstrtoull);

/**
 * kstrtoll - convert a string to a long long
 * @s: The start of the string. The string must be null-terminated, and may also
 *  include a single newline before its terminating null. The first character
 *  may also be a plus sign or a minus sign.
 * @base: The number base to use. The maximum supported base is 16. If base is
 *  given as 0, then the base of the string is automatically detected with the
 *  conventional semantics - If it begins with 0x the number will be parsed as a
 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 * @res: Where to write the result of the conversion on success.
 *
 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 * Preferred over simple_strtoll(). Return code must be checked.
 */
int kstrtoll(const char *s, unsigned int base, long long *res)
{
	unsigned long long tmp;
	int rv;

	if (s[0] == '-') {
		rv = _kstrtoull(s + 1, base, &tmp);
		if (rv < 0)
			return rv;
		if ((long long)-tmp > 0)
			return -ERANGE;
		*res = -tmp;
	} else {
		rv = kstrtoull(s, base, &tmp);
		if (rv < 0)
			return rv;
		if ((long long)tmp < 0)
			return -ERANGE;
		*res = tmp;
	}
	return 0;
}
EXPORT_SYMBOL(kstrtoll);

/* Internal, do not use. */
int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
{
	unsigned long long tmp;
	int rv;

	rv = kstrtoull(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (unsigned long)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(_kstrtoul);

/* Internal, do not use. */
int _kstrtol(const char *s, unsigned int base, long *res)
{
	long long tmp;
	int rv;

	rv = kstrtoll(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (long)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(_kstrtol);

/**
 * kstrtouint - convert a string to an unsigned int
 * @s: The start of the string. The string must be null-terminated, and may also
 *  include a single newline before its terminating null. The first character
 *  may also be a plus sign, but not a minus sign.
 * @base: The number base to use. The maximum supported base is 16. If base is
 *  given as 0, then the base of the string is automatically detected with the
 *  conventional semantics - If it begins with 0x the number will be parsed as a
 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 * @res: Where to write the result of the conversion on success.
 *
 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 * Preferred over simple_strtoul(). Return code must be checked.
 */
int kstrtouint(const char *s, unsigned int base, unsigned int *res)
{
	unsigned long long tmp;
	int rv;

	rv = kstrtoull(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (unsigned int)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtouint);

/**
 * kstrtoint - convert a string to an int
 * @s: The start of the string. The string must be null-terminated, and may also
 *  include a single newline before its terminating null. The first character
 *  may also be a plus sign or a minus sign.
 * @base: The number base to use. The maximum supported base is 16. If base is
 *  given as 0, then the base of the string is automatically detected with the
 *  conventional semantics - If it begins with 0x the number will be parsed as a
 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 * @res: Where to write the result of the conversion on success.
 *
 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 * Preferred over simple_strtol(). Return code must be checked.
 */
int kstrtoint(const char *s, unsigned int base, int *res)
{
	long long tmp;
	int rv;

	rv = kstrtoll(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (int)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtoint);

int kstrtou16(const char *s, unsigned int base, u16 *res)
{
	unsigned long long tmp;
	int rv;

	rv = kstrtoull(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (u16)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtou16);

int kstrtos16(const char *s, unsigned int base, s16 *res)
{
	long long tmp;
	int rv;

	rv = kstrtoll(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (s16)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtos16);

int kstrtou8(const char *s, unsigned int base, u8 *res)
{
	unsigned long long tmp;
	int rv;

	rv = kstrtoull(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (u8)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtou8);

int kstrtos8(const char *s, unsigned int base, s8 *res)
{
	long long tmp;
	int rv;

	rv = kstrtoll(s, base, &tmp);
	if (rv < 0)
		return rv;
	if (tmp != (s8)tmp)
		return -ERANGE;
	*res = tmp;
	return 0;
}
EXPORT_SYMBOL(kstrtos8);

/**
 * kstrtobool - convert common user inputs into boolean values
 * @s: input string
 * @res: result
 *
 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
 * pointed to by res is updated upon finding a match.
 */
int kstrtobool(const char *s, bool *res)
{
	if (!s)
		return -EINVAL;

	switch (s[0]) {
	case 'y':
	case 'Y':
	case '1':
		*res = true;
		return 0;
	case 'n':
	case 'N':
	case '0':
		*res = false;
		return 0;
	case 'o':
	case 'O':
		switch (s[1]) {
		case 'n':
		case 'N':
			*res = true;
			return 0;
		case 'f':
		case 'F':
			*res = false;
			return 0;
		default:
			break;
		}
		break;
	default:
		break;
	}

	return -EINVAL;
}
EXPORT_SYMBOL(kstrtobool);

/*
 * Since "base" would be a nonsense argument, this open-codes the
 * _from_user helper instead of using the helper macro below.
 */
int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
{
	/* Longest string needed to differentiate, newline, terminator */
	char buf[4];

	count = min(count, sizeof(buf) - 1);
	if (copy_from_user(buf, s, count))
		return -EFAULT;
	buf[count] = '\0';
	return kstrtobool(buf, res);
}
EXPORT_SYMBOL(kstrtobool_from_user);

#define kstrto_from_user(f, g, type)					\
int f(const char __user *s, size_t count, unsigned int base, type *res)	\
{									\
	/* sign, base 2 representation, newline, terminator */		\
	char buf[1 + sizeof(type) * 8 + 1 + 1];				\
									\
	count = min(count, sizeof(buf) - 1);				\
	if (copy_from_user(buf, s, count))				\
		return -EFAULT;						\
	buf[count] = '\0';						\
	return g(buf, base, res);					\
}									\
EXPORT_SYMBOL(f)

kstrto_from_user(kstrtoull_from_user,	kstrtoull,	unsigned long long);
kstrto_from_user(kstrtoll_from_user,	kstrtoll,	long long);
kstrto_from_user(kstrtoul_from_user,	kstrtoul,	unsigned long);
kstrto_from_user(kstrtol_from_user,	kstrtol,	long);
kstrto_from_user(kstrtouint_from_user,	kstrtouint,	unsigned int);
kstrto_from_user(kstrtoint_from_user,	kstrtoint,	int);
kstrto_from_user(kstrtou16_from_user,	kstrtou16,	u16);
kstrto_from_user(kstrtos16_from_user,	kstrtos16,	s16);
kstrto_from_user(kstrtou8_from_user,	kstrtou8,	u8);
kstrto_from_user(kstrtos8_from_user,	kstrtos8,	s8);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
33ee3b2e AD	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>
8bc3bcc9	17	#include <linux/export.h>
4c527293 AS	18	#include <linux/kstrtox.h>
4c527293 AS	19	#include <linux/math64.h>
33ee3b2e	20	#include <linux/types.h>
7c0f6ba6	21	#include <linux/uaccess.h>
4c527293	22
1dff46d6	23	#include "kstrtox.h"
33ee3b2e	24
1dff46d6	25	const char _parse_integer_fixup_radix(const char s, unsigned int *base)
33ee3b2e	26	{
1dff46d6	27	if (*base == 0) {
33ee3b2e AD	28	if (s[0] == '0') {
33ee3b2e AD	29	if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
1dff46d6	30	*base = 16;
33ee3b2e	31	else
1dff46d6	32	*base = 8;
33ee3b2e	33	} else
1dff46d6	34	*base = 10;
33ee3b2e	35	}
1dff46d6	36	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
33ee3b2e	37	s += 2;
1dff46d6 AD	38	return s;
	39	}
	40
	41	/*
	42	* Convert non-negative integer string representation in explicitly given radix
900fdc45 RF	43	* to an integer. A maximum of max_chars characters will be converted.
900fdc45 RF	44	*
1dff46d6 AD	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	*/
900fdc45 RF	50	unsigned int _parse_integer_limit(const char s, unsigned int base, unsigned long long p,
900fdc45 RF	51	size_t max_chars)
1dff46d6	52	{
690d137f	53	unsigned long long res;
1dff46d6	54	unsigned int rv;
33ee3b2e	55
690d137f	56	res = 0;
1dff46d6	57	rv = 0;
900fdc45	58	while (max_chars--) {
be5f3c77 AD	59	unsigned int c = *s;
be5f3c77 AD	60	unsigned int lc = c \| 0x20; /* don't tolower() this line */
33ee3b2e AD	61	unsigned int val;
33ee3b2e AD	62
be5f3c77 AD	63	if ('0' <= c && c <= '9')
	64	val = c - '0';
	65	else if ('a' <= lc && lc <= 'f')
	66	val = lc - 'a' + 10;
78be959e	67	else
1dff46d6	68	break;
33ee3b2e AD	69
33ee3b2e AD	70	if (val >= base)
1dff46d6	71	break;
690d137f DH	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))
8cfd56d4	78	rv \|= KSTRTOX_OVERFLOW;
690d137f DH	79	}
690d137f DH	80	res = res * base + val;
1dff46d6	81	rv++;
33ee3b2e AD	82	s++;
33ee3b2e AD	83	}
690d137f	84	*p = res;
1dff46d6 AD	85	return rv;
	86	}
	87
900fdc45 RF	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
1dff46d6 AD	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;
1dff46d6 AD	102	if (rv == 0)
	103	return -EINVAL;
	104	s += rv;
	105	if (*s == '\n')
	106	s++;
	107	if (*s)
33ee3b2e	108	return -EINVAL;
1dff46d6	109	*res = _res;
33ee3b2e AD	110	return 0;
	111	}
	112
4c925d60 EZ	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.
ef0f2685	126	* Preferred over simple_strtoull(). Return code must be checked.
4c925d60	127	*/
33ee3b2e AD	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
4c925d60 EZ	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.
ef0f2685	149	* Preferred over simple_strtoll(). Return code must be checked.
4c925d60	150	*/
33ee3b2e AD	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;
2d2e4715	160	if ((long long)-tmp > 0)
33ee3b2e AD	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. */
	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;
048e513d	184	if (tmp != (unsigned long)tmp)
33ee3b2e AD	185	return -ERANGE;
	186	*res = tmp;
	187	return 0;
	188	}
	189	EXPORT_SYMBOL(_kstrtoul);
	190
	191	/* Internal, do not use. */
	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;
048e513d	200	if (tmp != (long)tmp)
33ee3b2e AD	201	return -ERANGE;
	202	*res = tmp;
	203	return 0;
	204	}
	205	EXPORT_SYMBOL(_kstrtol);
	206
4c925d60 EZ	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.
ef0f2685	220	* Preferred over simple_strtoul(). Return code must be checked.
4c925d60	221	*/
33ee3b2e AD	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;
048e513d	230	if (tmp != (unsigned int)tmp)
33ee3b2e AD	231	return -ERANGE;
	232	*res = tmp;
	233	return 0;
	234	}
	235	EXPORT_SYMBOL(kstrtouint);
	236
4c925d60 EZ	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.
ef0f2685	250	* Preferred over simple_strtol(). Return code must be checked.
4c925d60	251	*/
33ee3b2e AD	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;
048e513d	260	if (tmp != (int)tmp)
33ee3b2e AD	261	return -ERANGE;
	262	*res = tmp;
	263	return 0;
	264	}
	265	EXPORT_SYMBOL(kstrtoint);
	266
	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;
048e513d	275	if (tmp != (u16)tmp)
33ee3b2e AD	276	return -ERANGE;
	277	*res = tmp;
	278	return 0;
	279	}
	280	EXPORT_SYMBOL(kstrtou16);
	281
	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;
048e513d	290	if (tmp != (s16)tmp)
33ee3b2e AD	291	return -ERANGE;
	292	*res = tmp;
	293	return 0;
	294	}
	295	EXPORT_SYMBOL(kstrtos16);
	296
	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;
048e513d	305	if (tmp != (u8)tmp)
33ee3b2e AD	306	return -ERANGE;
	307	*res = tmp;
	308	return 0;
	309	}
	310	EXPORT_SYMBOL(kstrtou8);
	311
	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;
048e513d	320	if (tmp != (s8)tmp)
33ee3b2e AD	321	return -ERANGE;
	322	*res = tmp;
	323	return 0;
	324	}
	325	EXPORT_SYMBOL(kstrtos8);
c196e32a	326
ef951599 KC	327	/**
	328	* kstrtobool - convert common user inputs into boolean values
	329	* @s: input string
	330	* @res: result
	331	*
a81a5a17 KC	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.
ef951599 KC	335	*/
	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;
a81a5a17 KC	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	}
36f9ff9e	366	break;
ef951599 KC	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	*/
	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
c196e32a AD	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);