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Diffstat (limited to 'lib/kstrtox.c')
| -rw-r--r-- | lib/kstrtox.c | 541 |
1 files changed, 541 insertions, 0 deletions
diff --git a/lib/kstrtox.c b/lib/kstrtox.c new file mode 100644 index 000000000..bac1c057e --- /dev/null +++ b/lib/kstrtox.c @@ -0,0 +1,541 @@ +// 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/overflow.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#include "kstrtox.h" + +noinline +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; +} + +/** + * _parse_integer_limit - Convert integer string representation to an integer + * @s: Integer string representation + * @base: Radix + * @p: Where to store result + * @max_chars: Maximum amount of characters to convert + * @init: Initial value of the multiply-accumulate result + * + * Convert non-negative integer string representation in explicitly given + * radix to an integer. If overflow occurs, value at @p is set to ULLONG_MAX. + * + * This function is the workhorse of other string conversion functions and it + * is discouraged to use it explicitly. Consider kstrto*() family instead. + * + * Return: Number of characters consumed, maybe ORed with overflow bit + */ +noinline +unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p, + size_t max_chars, unsigned long long init) +{ + unsigned int rv, overflow = 0; + unsigned long long res; + + res = init; + for (rv = 0; rv < max_chars; rv++, s++) { + unsigned int c = *s; + unsigned int lc = _tolower(c); + 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 (check_mul_overflow(res, base, &res) || + check_add_overflow(res, val, &res)) { + res = ULLONG_MAX; + overflow = KSTRTOX_OVERFLOW; + } + } else { + res = res * base + val; + } + } + *p = res; + return rv | overflow; +} + +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. + */ +noinline +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. + */ +noinline +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. + */ +noinline +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. + */ +noinline +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); + +noinline +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); + +noinline +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); + +noinline +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); + +noinline +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 'EeYyTt1DdNnFf0', + * or [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value + * pointed to by res is updated upon finding a match. + */ +noinline +int kstrtobool(const char *s, bool *res) +{ + if (!s) + return -EINVAL; + + switch (s[0]) { + case 'e': + case 'E': + case 'y': + case 'Y': + case 't': + case 'T': + case '1': + *res = true; + return 0; + case 'd': + case 'D': + case 'n': + case 'N': + case 'f': + case 'F': + 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); + +static int _kstrtoudec64(const char *s, unsigned int scale, u64 *res) +{ + unsigned int rv_int, rv_frac; + u64 _res = 0; + + rv_int = _parse_integer(s, 10, &_res); + if (rv_int & KSTRTOX_OVERFLOW) + return -ERANGE; + s += rv_int; + + if (*s == '.') + s++; /* skip decimal point */ + + rv_frac = _parse_integer(s, 10, &_res, scale, _res); + if (rv_frac & KSTRTOX_OVERFLOW) + return -ERANGE; + s += rv_frac; + + /* + * Check input beyond rv_int and rv_frac to cover cases like ".5" with + * scale 0, which is considered a valid input, being parsed as 0. + */ + if (!rv_int && !rv_frac && !isdigit(*s)) + return -EINVAL; + + while (isdigit(*s)) /* truncate digits */ + s++; + + if (*s == '\n') + s++; + if (*s) + return -EINVAL; + + if (_res && ((scale - rv_frac) > 19 /* log10(2^64) = 19.26 */ || + check_mul_overflow(_res, int_pow(10, scale - rv_frac), &_res))) + return -ERANGE; + + *res = _res; + return 0; +} + +/** + * kstrtoudec64() - Convert a string to an unsigned 64-bit scaled decimal value. + * @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. + * @scale: The number of digits to the right of the decimal point. + * @res: Where to write the result of the conversion on success. + * + * For example, a scale of 3 with input "123.45" results in 123450. Note that + * trailing zeros in the fractional part input to match the scale are not + * required. Also, digits beyond the specified scale are ignored. + * + * Return: 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + */ +noinline +int kstrtoudec64(const char *s, unsigned int scale, u64 *res) +{ + if (s[0] == '+') + s++; + return _kstrtoudec64(s, scale, res); +} +EXPORT_SYMBOL(kstrtoudec64); + +/** + * kstrtodec64() - Convert a string to a signed 64-bit scaled decimal value. + * @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. + * @scale: The number of digits to the right of the decimal point. + * @res: Where to write the result of the conversion on success. + * + * For example, a scale of 4 with input "-3.141592" results in -31415. Note + * that digits beyond the specified scale are ignored. Also, trailing zeros in + * the fractional part input to match the scale are not required. + * + * Return: 0 on success, -ERANGE on overflow and -EINVAL on parsing error. + */ +noinline +int kstrtodec64(const char *s, unsigned int scale, s64 *res) +{ + u64 tmp; + int rv; + + if (s[0] == '-') { + rv = _kstrtoudec64(s + 1, scale, &tmp); + if (rv < 0) + return rv; + if ((s64)-tmp > 0) + return -ERANGE; + *res = -tmp; + } else { + rv = kstrtoudec64(s, scale, &tmp); + if (rv < 0) + return rv; + if ((s64)tmp < 0) + return -ERANGE; + *res = tmp; + } + return 0; +} +EXPORT_SYMBOL(kstrtodec64); + +/* + * 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); |