e846c2821c
[ Upstream commit 900fdc4573766dd43b847b4f54bd4a1ee2bc7360 ]
The existing code attempted to handle numbers by doing a strto[u]l(),
ignoring the field width, and then repeatedly dividing to extract the
field out of the full converted value. If the string contains a run of
valid digits longer than will fit in a long or long long, this would
overflow and no amount of dividing can recover the correct value.
This patch fixes vsscanf() to obey number field widths when parsing
the number.
A new _parse_integer_limit() is added that takes a limit for the number
of characters to parse. The number field conversion in vsscanf is changed
to use this new function.
If a number starts with a radix prefix, the field width must be long
enough for at last one digit after the prefix. If not, it will be handled
like this:
sscanf("0x4", "%1i", &i): i=0, scanning continues with the 'x'
sscanf("0x4", "%2i", &i): i=0, scanning continues with the '4'
This is consistent with the observed behaviour of userland sscanf.
Note that this patch does NOT fix the problem of a single field value
overflowing the target type. So for example:
sscanf("123456789abcdef", "%x", &i);
Will not produce the correct result because the value obviously overflows
INT_MAX. But sscanf will report a successful conversion.
Note that where a very large number is used to mean "unlimited", the value
INT_MAX is used for consistency with the behaviour of vsnprintf().
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210514161206.30821-2-rf@opensource.cirrus.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
418 lines
11 KiB
C
418 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Convert integer string representation to an integer.
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* If an integer doesn't fit into specified type, -E is returned.
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*
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* Integer starts with optional sign.
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* kstrtou*() functions do not accept sign "-".
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*
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* Radix 0 means autodetection: leading "0x" implies radix 16,
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* leading "0" implies radix 8, otherwise radix is 10.
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* Autodetection hints work after optional sign, but not before.
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*
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* If -E is returned, result is not touched.
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*/
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/math64.h>
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#include <linux/export.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include "kstrtox.h"
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const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
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{
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if (*base == 0) {
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if (s[0] == '0') {
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if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
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*base = 16;
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else
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*base = 8;
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} else
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*base = 10;
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}
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if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
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s += 2;
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return s;
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}
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/*
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* Convert non-negative integer string representation in explicitly given radix
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* to an integer. A maximum of max_chars characters will be converted.
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*
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* Return number of characters consumed maybe or-ed with overflow bit.
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* If overflow occurs, result integer (incorrect) is still returned.
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*
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* Don't you dare use this function.
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*/
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unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
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size_t max_chars)
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{
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unsigned long long res;
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unsigned int rv;
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res = 0;
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rv = 0;
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while (max_chars--) {
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unsigned int c = *s;
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unsigned int lc = c | 0x20; /* don't tolower() this line */
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unsigned int val;
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if ('0' <= c && c <= '9')
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val = c - '0';
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else if ('a' <= lc && lc <= 'f')
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val = lc - 'a' + 10;
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else
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break;
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if (val >= base)
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break;
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/*
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* Check for overflow only if we are within range of
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* it in the max base we support (16)
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*/
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if (unlikely(res & (~0ull << 60))) {
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if (res > div_u64(ULLONG_MAX - val, base))
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rv |= KSTRTOX_OVERFLOW;
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}
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res = res * base + val;
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rv++;
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s++;
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}
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*p = res;
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return rv;
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}
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unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
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{
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return _parse_integer_limit(s, base, p, INT_MAX);
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}
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static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
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{
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unsigned long long _res;
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unsigned int rv;
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s = _parse_integer_fixup_radix(s, &base);
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rv = _parse_integer(s, base, &_res);
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if (rv & KSTRTOX_OVERFLOW)
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return -ERANGE;
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if (rv == 0)
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return -EINVAL;
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s += rv;
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if (*s == '\n')
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s++;
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if (*s)
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return -EINVAL;
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*res = _res;
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return 0;
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}
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/**
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* kstrtoull - convert a string to an unsigned long long
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* @s: The start of the string. The string must be null-terminated, and may also
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* include a single newline before its terminating null. The first character
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* may also be a plus sign, but not a minus sign.
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* @base: The number base to use. The maximum supported base is 16. If base is
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* given as 0, then the base of the string is automatically detected with the
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* conventional semantics - If it begins with 0x the number will be parsed as a
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* hexadecimal (case insensitive), if it otherwise begins with 0, it will be
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* parsed as an octal number. Otherwise it will be parsed as a decimal.
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* @res: Where to write the result of the conversion on success.
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*
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* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
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* Used as a replacement for the obsolete simple_strtoull. Return code must
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* be checked.
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*/
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int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
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{
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if (s[0] == '+')
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s++;
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return _kstrtoull(s, base, res);
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}
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EXPORT_SYMBOL(kstrtoull);
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/**
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* kstrtoll - convert a string to a long long
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* @s: The start of the string. The string must be null-terminated, and may also
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* include a single newline before its terminating null. The first character
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* may also be a plus sign or a minus sign.
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* @base: The number base to use. The maximum supported base is 16. If base is
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* given as 0, then the base of the string is automatically detected with the
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* conventional semantics - If it begins with 0x the number will be parsed as a
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* hexadecimal (case insensitive), if it otherwise begins with 0, it will be
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* parsed as an octal number. Otherwise it will be parsed as a decimal.
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* @res: Where to write the result of the conversion on success.
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*
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* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
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* Used as a replacement for the obsolete simple_strtoull. Return code must
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* be checked.
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*/
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int kstrtoll(const char *s, unsigned int base, long long *res)
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{
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unsigned long long tmp;
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int rv;
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if (s[0] == '-') {
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rv = _kstrtoull(s + 1, base, &tmp);
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if (rv < 0)
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return rv;
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if ((long long)-tmp > 0)
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return -ERANGE;
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*res = -tmp;
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} else {
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rv = kstrtoull(s, base, &tmp);
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if (rv < 0)
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return rv;
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if ((long long)tmp < 0)
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return -ERANGE;
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*res = tmp;
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}
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return 0;
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}
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EXPORT_SYMBOL(kstrtoll);
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/* Internal, do not use. */
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int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
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{
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unsigned long long tmp;
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int rv;
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rv = kstrtoull(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (unsigned long)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(_kstrtoul);
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/* Internal, do not use. */
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int _kstrtol(const char *s, unsigned int base, long *res)
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{
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long long tmp;
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int rv;
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rv = kstrtoll(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (long)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(_kstrtol);
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/**
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* kstrtouint - convert a string to an unsigned int
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* @s: The start of the string. The string must be null-terminated, and may also
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* include a single newline before its terminating null. The first character
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* may also be a plus sign, but not a minus sign.
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* @base: The number base to use. The maximum supported base is 16. If base is
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* given as 0, then the base of the string is automatically detected with the
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* conventional semantics - If it begins with 0x the number will be parsed as a
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* hexadecimal (case insensitive), if it otherwise begins with 0, it will be
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* parsed as an octal number. Otherwise it will be parsed as a decimal.
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* @res: Where to write the result of the conversion on success.
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*
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* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
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* Used as a replacement for the obsolete simple_strtoull. Return code must
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* be checked.
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*/
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int kstrtouint(const char *s, unsigned int base, unsigned int *res)
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{
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unsigned long long tmp;
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int rv;
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rv = kstrtoull(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (unsigned int)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtouint);
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/**
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* kstrtoint - convert a string to an int
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* @s: The start of the string. The string must be null-terminated, and may also
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* include a single newline before its terminating null. The first character
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* may also be a plus sign or a minus sign.
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* @base: The number base to use. The maximum supported base is 16. If base is
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* given as 0, then the base of the string is automatically detected with the
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* conventional semantics - If it begins with 0x the number will be parsed as a
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* hexadecimal (case insensitive), if it otherwise begins with 0, it will be
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* parsed as an octal number. Otherwise it will be parsed as a decimal.
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* @res: Where to write the result of the conversion on success.
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*
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* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
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* Used as a replacement for the obsolete simple_strtoull. Return code must
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* be checked.
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*/
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int kstrtoint(const char *s, unsigned int base, int *res)
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{
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long long tmp;
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int rv;
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rv = kstrtoll(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (int)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtoint);
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int kstrtou16(const char *s, unsigned int base, u16 *res)
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{
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unsigned long long tmp;
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int rv;
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rv = kstrtoull(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (u16)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtou16);
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int kstrtos16(const char *s, unsigned int base, s16 *res)
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{
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long long tmp;
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int rv;
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rv = kstrtoll(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (s16)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtos16);
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int kstrtou8(const char *s, unsigned int base, u8 *res)
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{
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unsigned long long tmp;
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int rv;
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rv = kstrtoull(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (u8)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtou8);
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int kstrtos8(const char *s, unsigned int base, s8 *res)
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{
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long long tmp;
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int rv;
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rv = kstrtoll(s, base, &tmp);
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if (rv < 0)
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return rv;
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if (tmp != (s8)tmp)
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return -ERANGE;
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*res = tmp;
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return 0;
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}
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EXPORT_SYMBOL(kstrtos8);
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/**
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* kstrtobool - convert common user inputs into boolean values
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* @s: input string
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* @res: result
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*
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* This routine returns 0 iff the first character is one of 'Yy1Nn0', or
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* [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
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* pointed to by res is updated upon finding a match.
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*/
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int kstrtobool(const char *s, bool *res)
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{
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if (!s)
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return -EINVAL;
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switch (s[0]) {
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case 'y':
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case 'Y':
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case '1':
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*res = true;
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return 0;
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case 'n':
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case 'N':
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case '0':
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*res = false;
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return 0;
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case 'o':
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case 'O':
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switch (s[1]) {
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case 'n':
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case 'N':
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*res = true;
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return 0;
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case 'f':
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case 'F':
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*res = false;
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return 0;
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default:
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break;
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}
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default:
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break;
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL(kstrtobool);
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/*
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* Since "base" would be a nonsense argument, this open-codes the
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* _from_user helper instead of using the helper macro below.
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*/
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int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
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{
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/* Longest string needed to differentiate, newline, terminator */
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char buf[4];
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count = min(count, sizeof(buf) - 1);
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if (copy_from_user(buf, s, count))
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return -EFAULT;
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buf[count] = '\0';
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return kstrtobool(buf, res);
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}
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EXPORT_SYMBOL(kstrtobool_from_user);
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#define kstrto_from_user(f, g, type) \
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int f(const char __user *s, size_t count, unsigned int base, type *res) \
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{ \
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/* sign, base 2 representation, newline, terminator */ \
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char buf[1 + sizeof(type) * 8 + 1 + 1]; \
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\
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count = min(count, sizeof(buf) - 1); \
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if (copy_from_user(buf, s, count)) \
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return -EFAULT; \
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buf[count] = '\0'; \
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return g(buf, base, res); \
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} \
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EXPORT_SYMBOL(f)
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kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);
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kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);
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kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);
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kstrto_from_user(kstrtol_from_user, kstrtol, long);
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kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);
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kstrto_from_user(kstrtoint_from_user, kstrtoint, int);
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kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
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kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
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kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
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kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
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