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![Alexey Dobriyan](/assets/img/avatar_default.png)
gcc does generates stupid code sign extending data back and forth. Help by using "unsigned int". add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-61 (-61) function old new delta _parse_integer 128 123 -5 It _still_ does generate useless MOVSX but I don't know how to delete it: 0000000000000070 <_parse_integer>: ... a0: 89 c2 mov edx,eax a2: 83 e8 30 sub eax,0x30 a5: 83 f8 09 cmp eax,0x9 a8: 76 11 jbe bb <_parse_integer+0x4b> aa: 83 ca 20 or edx,0x20 ad: 0f be c2 ===> movsx eax,dl <=== useless b0: 8d 50 9f lea edx,[rax-0x61] b3: 83 fa 05 cmp edx,0x5 Patch also helps on embedded archs which generally only like "int". On arm "and 0xff" is generated which is waste because all values used in comparisons are positive. Link: http://lkml.kernel.org/r/20170514194720.GB32563@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
409 lines
11 KiB
C
409 lines
11 KiB
C
/*
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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.
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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(const char *s, unsigned int base, unsigned long long *p)
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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 (1) {
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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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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 long)(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 long)(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 long long)(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 != (long long)(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 != (unsigned long long)(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 != (long long)(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 != (unsigned long long)(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 != (long long)(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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