linux/lib/kstrtox.c
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   1/*
   2 * Convert integer string representation to an integer.
   3 * If an integer doesn't fit into specified type, -E is returned.
   4 *
   5 * Integer starts with optional sign.
   6 * kstrtou*() functions do not accept sign "-".
   7 *
   8 * Radix 0 means autodetection: leading "0x" implies radix 16,
   9 * leading "0" implies radix 8, otherwise radix is 10.
  10 * Autodetection hints work after optional sign, but not before.
  11 *
  12 * If -E is returned, result is not touched.
  13 */
  14#include <linux/ctype.h>
  15#include <linux/errno.h>
  16#include <linux/kernel.h>
  17#include <linux/math64.h>
  18#include <linux/module.h>
  19#include <linux/types.h>
  20#include <asm/uaccess.h>
  21#include "kstrtox.h"
  22
  23const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
  24{
  25        if (*base == 0) {
  26                if (s[0] == '0') {
  27                        if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
  28                                *base = 16;
  29                        else
  30                                *base = 8;
  31                } else
  32                        *base = 10;
  33        }
  34        if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
  35                s += 2;
  36        return s;
  37}
  38
  39/*
  40 * Convert non-negative integer string representation in explicitly given radix
  41 * to an integer.
  42 * Return number of characters consumed maybe or-ed with overflow bit.
  43 * If overflow occurs, result integer (incorrect) is still returned.
  44 *
  45 * Don't you dare use this function.
  46 */
  47unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res)
  48{
  49        unsigned int rv;
  50        int overflow;
  51
  52        *res = 0;
  53        rv = 0;
  54        overflow = 0;
  55        while (*s) {
  56                unsigned int val;
  57
  58                if ('0' <= *s && *s <= '9')
  59                        val = *s - '0';
  60                else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
  61                        val = _tolower(*s) - 'a' + 10;
  62                else
  63                        break;
  64
  65                if (val >= base)
  66                        break;
  67                if (*res > div_u64(ULLONG_MAX - val, base))
  68                        overflow = 1;
  69                *res = *res * base + val;
  70                rv++;
  71                s++;
  72        }
  73        if (overflow)
  74                rv |= KSTRTOX_OVERFLOW;
  75        return rv;
  76}
  77
  78static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
  79{
  80        unsigned long long _res;
  81        unsigned int rv;
  82
  83        s = _parse_integer_fixup_radix(s, &base);
  84        rv = _parse_integer(s, base, &_res);
  85        if (rv & KSTRTOX_OVERFLOW)
  86                return -ERANGE;
  87        rv &= ~KSTRTOX_OVERFLOW;
  88        if (rv == 0)
  89                return -EINVAL;
  90        s += rv;
  91        if (*s == '\n')
  92                s++;
  93        if (*s)
  94                return -EINVAL;
  95        *res = _res;
  96        return 0;
  97}
  98
  99int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 100{
 101        if (s[0] == '+')
 102                s++;
 103        return _kstrtoull(s, base, res);
 104}
 105EXPORT_SYMBOL(kstrtoull);
 106
 107int kstrtoll(const char *s, unsigned int base, long long *res)
 108{
 109        unsigned long long tmp;
 110        int rv;
 111
 112        if (s[0] == '-') {
 113                rv = _kstrtoull(s + 1, base, &tmp);
 114                if (rv < 0)
 115                        return rv;
 116                if ((long long)(-tmp) >= 0)
 117                        return -ERANGE;
 118                *res = -tmp;
 119        } else {
 120                rv = kstrtoull(s, base, &tmp);
 121                if (rv < 0)
 122                        return rv;
 123                if ((long long)tmp < 0)
 124                        return -ERANGE;
 125                *res = tmp;
 126        }
 127        return 0;
 128}
 129EXPORT_SYMBOL(kstrtoll);
 130
 131/* Internal, do not use. */
 132int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
 133{
 134        unsigned long long tmp;
 135        int rv;
 136
 137        rv = kstrtoull(s, base, &tmp);
 138        if (rv < 0)
 139                return rv;
 140        if (tmp != (unsigned long long)(unsigned long)tmp)
 141                return -ERANGE;
 142        *res = tmp;
 143        return 0;
 144}
 145EXPORT_SYMBOL(_kstrtoul);
 146
 147/* Internal, do not use. */
 148int _kstrtol(const char *s, unsigned int base, long *res)
 149{
 150        long long tmp;
 151        int rv;
 152
 153        rv = kstrtoll(s, base, &tmp);
 154        if (rv < 0)
 155                return rv;
 156        if (tmp != (long long)(long)tmp)
 157                return -ERANGE;
 158        *res = tmp;
 159        return 0;
 160}
 161EXPORT_SYMBOL(_kstrtol);
 162
 163int kstrtouint(const char *s, unsigned int base, unsigned int *res)
 164{
 165        unsigned long long tmp;
 166        int rv;
 167
 168        rv = kstrtoull(s, base, &tmp);
 169        if (rv < 0)
 170                return rv;
 171        if (tmp != (unsigned long long)(unsigned int)tmp)
 172                return -ERANGE;
 173        *res = tmp;
 174        return 0;
 175}
 176EXPORT_SYMBOL(kstrtouint);
 177
 178int kstrtoint(const char *s, unsigned int base, int *res)
 179{
 180        long long tmp;
 181        int rv;
 182
 183        rv = kstrtoll(s, base, &tmp);
 184        if (rv < 0)
 185                return rv;
 186        if (tmp != (long long)(int)tmp)
 187                return -ERANGE;
 188        *res = tmp;
 189        return 0;
 190}
 191EXPORT_SYMBOL(kstrtoint);
 192
 193int kstrtou16(const char *s, unsigned int base, u16 *res)
 194{
 195        unsigned long long tmp;
 196        int rv;
 197
 198        rv = kstrtoull(s, base, &tmp);
 199        if (rv < 0)
 200                return rv;
 201        if (tmp != (unsigned long long)(u16)tmp)
 202                return -ERANGE;
 203        *res = tmp;
 204        return 0;
 205}
 206EXPORT_SYMBOL(kstrtou16);
 207
 208int kstrtos16(const char *s, unsigned int base, s16 *res)
 209{
 210        long long tmp;
 211        int rv;
 212
 213        rv = kstrtoll(s, base, &tmp);
 214        if (rv < 0)
 215                return rv;
 216        if (tmp != (long long)(s16)tmp)
 217                return -ERANGE;
 218        *res = tmp;
 219        return 0;
 220}
 221EXPORT_SYMBOL(kstrtos16);
 222
 223int kstrtou8(const char *s, unsigned int base, u8 *res)
 224{
 225        unsigned long long tmp;
 226        int rv;
 227
 228        rv = kstrtoull(s, base, &tmp);
 229        if (rv < 0)
 230                return rv;
 231        if (tmp != (unsigned long long)(u8)tmp)
 232                return -ERANGE;
 233        *res = tmp;
 234        return 0;
 235}
 236EXPORT_SYMBOL(kstrtou8);
 237
 238int kstrtos8(const char *s, unsigned int base, s8 *res)
 239{
 240        long long tmp;
 241        int rv;
 242
 243        rv = kstrtoll(s, base, &tmp);
 244        if (rv < 0)
 245                return rv;
 246        if (tmp != (long long)(s8)tmp)
 247                return -ERANGE;
 248        *res = tmp;
 249        return 0;
 250}
 251EXPORT_SYMBOL(kstrtos8);
 252
 253#define kstrto_from_user(f, g, type)                                    \
 254int f(const char __user *s, size_t count, unsigned int base, type *res) \
 255{                                                                       \
 256        /* sign, base 2 representation, newline, terminator */          \
 257        char buf[1 + sizeof(type) * 8 + 1 + 1];                         \
 258                                                                        \
 259        count = min(count, sizeof(buf) - 1);                            \
 260        if (copy_from_user(buf, s, count))                              \
 261                return -EFAULT;                                         \
 262        buf[count] = '\0';                                              \
 263        return g(buf, base, res);                                       \
 264}                                                                       \
 265EXPORT_SYMBOL(f)
 266
 267kstrto_from_user(kstrtoull_from_user,   kstrtoull,      unsigned long long);
 268kstrto_from_user(kstrtoll_from_user,    kstrtoll,       long long);
 269kstrto_from_user(kstrtoul_from_user,    kstrtoul,       unsigned long);
 270kstrto_from_user(kstrtol_from_user,     kstrtol,        long);
 271kstrto_from_user(kstrtouint_from_user,  kstrtouint,     unsigned int);
 272kstrto_from_user(kstrtoint_from_user,   kstrtoint,      int);
 273kstrto_from_user(kstrtou16_from_user,   kstrtou16,      u16);
 274kstrto_from_user(kstrtos16_from_user,   kstrtos16,      s16);
 275kstrto_from_user(kstrtou8_from_user,    kstrtou8,       u8);
 276kstrto_from_user(kstrtos8_from_user,    kstrtos8,       s8);
 277
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