LXR linux/lib/kstrtox.c

   1// SPDX-License-Identifier: GPL-2.0
   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>
  17#include <linux/kernel.h>
  18#include <linux/math64.h>
  19#include <linux/export.h>
  20#include <linux/types.h>
  21#include <linux/uaccess.h>
  22#include "kstrtox.h"
  23
  24const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
  25{
  26        if (*base == 0) {
  27                if (s[0] == '0') {
  28                        if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
  29                                *base = 16;
  30                        else
  31                                *base = 8;
  32                } else
  33                        *base = 10;
  34        }
  35        if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
  36                s += 2;
  37        return s;
  38}
  39
  40/*
  41 * Convert non-negative integer string representation in explicitly given radix
  42 * to an integer.
  43 * Return number of characters consumed maybe or-ed with overflow bit.
  44 * If overflow occurs, result integer (incorrect) is still returned.
  45 *
  46 * Don't you dare use this function.
  47 */
  48unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
  49{
  50        unsigned long long res;
  51        unsigned int rv;
  52
  53        res = 0;
  54        rv = 0;
  55        while (1) {
  56                unsigned int c = *s;
  57                unsigned int lc = c | 0x20; /* don't tolower() this line */
  58                unsigned int val;
  59
  60                if ('0' <= c && c <= '9')
  61                        val = c - '0';
  62                else if ('a' <= lc && lc <= 'f')
  63                        val = lc - 'a' + 10;
  64                else
  65                        break;
  66
  67                if (val >= base)
  68                        break;
  69                /*
  70                 * Check for overflow only if we are within range of
  71                 * it in the max base we support (16)
  72                 */
  73                if (unlikely(res & (~0ull << 60))) {
  74                        if (res > div_u64(ULLONG_MAX - val, base))
  75                                rv |= KSTRTOX_OVERFLOW;
  76                }
  77                res = res * base + val;
  78                rv++;
  79                s++;
  80        }
  81        *p = res;
  82        return rv;
  83}
  84
  85static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
  86{
  87        unsigned long long _res;
  88        unsigned int rv;
  89
  90        s = _parse_integer_fixup_radix(s, &base);
  91        rv = _parse_integer(s, base, &_res);
  92        if (rv & KSTRTOX_OVERFLOW)
  93                return -ERANGE;
  94        if (rv == 0)
  95                return -EINVAL;
  96        s += rv;
  97        if (*s == '\n')
  98                s++;
  99        if (*s)
 100                return -EINVAL;
 101        *res = _res;
 102        return 0;
 103}
 104
 105/**
 106 * kstrtoull - convert a string to an unsigned long long
 107 * @s: The start of the string. The string must be null-terminated, and may also
 108 *  include a single newline before its terminating null. The first character
 109 *  may also be a plus sign, but not a minus sign.
 110 * @base: The number base to use. The maximum supported base is 16. If base is
 111 *  given as 0, then the base of the string is automatically detected with the
 112 *  conventional semantics - If it begins with 0x the number will be parsed as a
 113 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 114 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 115 * @res: Where to write the result of the conversion on success.
 116 *
 117 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 118 * Preferred over simple_strtoull(). Return code must be checked.
 119 */
 120int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 121{
 122        if (s[0] == '+')
 123                s++;
 124        return _kstrtoull(s, base, res);
 125}
 126EXPORT_SYMBOL(kstrtoull);
 127
 128/**
 129 * kstrtoll - convert a string to a long long
 130 * @s: The start of the string. The string must be null-terminated, and may also
 131 *  include a single newline before its terminating null. The first character
 132 *  may also be a plus sign or a minus sign.
 133 * @base: The number base to use. The maximum supported base is 16. If base is
 134 *  given as 0, then the base of the string is automatically detected with the
 135 *  conventional semantics - If it begins with 0x the number will be parsed as a
 136 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 137 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 138 * @res: Where to write the result of the conversion on success.
 139 *
 140 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 141 * Preferred over simple_strtoll(). Return code must be checked.
 142 */
 143int kstrtoll(const char *s, unsigned int base, long long *res)
 144{
 145        unsigned long long tmp;
 146        int rv;
 147
 148        if (s[0] == '-') {
 149                rv = _kstrtoull(s + 1, base, &tmp);
 150                if (rv < 0)
 151                        return rv;
 152                if ((long long)-tmp > 0)
 153                        return -ERANGE;
 154                *res = -tmp;
 155        } else {
 156                rv = kstrtoull(s, base, &tmp);
 157                if (rv < 0)
 158                        return rv;
 159                if ((long long)tmp < 0)
 160                        return -ERANGE;
 161                *res = tmp;
 162        }
 163        return 0;
 164}
 165EXPORT_SYMBOL(kstrtoll);
 166
 167/* Internal, do not use. */
 168int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
 169{
 170        unsigned long long tmp;
 171        int rv;
 172
 173        rv = kstrtoull(s, base, &tmp);
 174        if (rv < 0)
 175                return rv;
 176        if (tmp != (unsigned long)tmp)
 177                return -ERANGE;
 178        *res = tmp;
 179        return 0;
 180}
 181EXPORT_SYMBOL(_kstrtoul);
 182
 183/* Internal, do not use. */
 184int _kstrtol(const char *s, unsigned int base, long *res)
 185{
 186        long long tmp;
 187        int rv;
 188
 189        rv = kstrtoll(s, base, &tmp);
 190        if (rv < 0)
 191                return rv;
 192        if (tmp != (long)tmp)
 193                return -ERANGE;
 194        *res = tmp;
 195        return 0;
 196}
 197EXPORT_SYMBOL(_kstrtol);
 198
 199/**
 200 * kstrtouint - convert a string to an unsigned int
 201 * @s: The start of the string. The string must be null-terminated, and may also
 202 *  include a single newline before its terminating null. The first character
 203 *  may also be a plus sign, but not a minus sign.
 204 * @base: The number base to use. The maximum supported base is 16. If base is
 205 *  given as 0, then the base of the string is automatically detected with the
 206 *  conventional semantics - If it begins with 0x the number will be parsed as a
 207 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 208 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 209 * @res: Where to write the result of the conversion on success.
 210 *
 211 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 212 * Preferred over simple_strtoul(). Return code must be checked.
 213 */
 214int kstrtouint(const char *s, unsigned int base, unsigned int *res)
 215{
 216        unsigned long long tmp;
 217        int rv;
 218
 219        rv = kstrtoull(s, base, &tmp);
 220        if (rv < 0)
 221                return rv;
 222        if (tmp != (unsigned int)tmp)
 223                return -ERANGE;
 224        *res = tmp;
 225        return 0;
 226}
 227EXPORT_SYMBOL(kstrtouint);
 228
 229/**
 230 * kstrtoint - convert a string to an int
 231 * @s: The start of the string. The string must be null-terminated, and may also
 232 *  include a single newline before its terminating null. The first character
 233 *  may also be a plus sign or a minus sign.
 234 * @base: The number base to use. The maximum supported base is 16. If base is
 235 *  given as 0, then the base of the string is automatically detected with the
 236 *  conventional semantics - If it begins with 0x the number will be parsed as a
 237 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 238 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 239 * @res: Where to write the result of the conversion on success.
 240 *
 241 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 242 * Preferred over simple_strtol(). Return code must be checked.
 243 */
 244int kstrtoint(const char *s, unsigned int base, int *res)
 245{
 246        long long tmp;
 247        int rv;
 248
 249        rv = kstrtoll(s, base, &tmp);
 250        if (rv < 0)
 251                return rv;
 252        if (tmp != (int)tmp)
 253                return -ERANGE;
 254        *res = tmp;
 255        return 0;
 256}
 257EXPORT_SYMBOL(kstrtoint);
 258
 259int kstrtou16(const char *s, unsigned int base, u16 *res)
 260{
 261        unsigned long long tmp;
 262        int rv;
 263
 264        rv = kstrtoull(s, base, &tmp);
 265        if (rv < 0)
 266                return rv;
 267        if (tmp != (u16)tmp)
 268                return -ERANGE;
 269        *res = tmp;
 270        return 0;
 271}
 272EXPORT_SYMBOL(kstrtou16);
 273
 274int kstrtos16(const char *s, unsigned int base, s16 *res)
 275{
 276        long long tmp;
 277        int rv;
 278
 279        rv = kstrtoll(s, base, &tmp);
 280        if (rv < 0)
 281                return rv;
 282        if (tmp != (s16)tmp)
 283                return -ERANGE;
 284        *res = tmp;
 285        return 0;
 286}
 287EXPORT_SYMBOL(kstrtos16);
 288
 289int kstrtou8(const char *s, unsigned int base, u8 *res)
 290{
 291        unsigned long long tmp;
 292        int rv;
 293
 294        rv = kstrtoull(s, base, &tmp);
 295        if (rv < 0)
 296                return rv;
 297        if (tmp != (u8)tmp)
 298                return -ERANGE;
 299        *res = tmp;
 300        return 0;
 301}
 302EXPORT_SYMBOL(kstrtou8);
 303
 304int kstrtos8(const char *s, unsigned int base, s8 *res)
 305{
 306        long long tmp;
 307        int rv;
 308
 309        rv = kstrtoll(s, base, &tmp);
 310        if (rv < 0)
 311                return rv;
 312        if (tmp != (s8)tmp)
 313                return -ERANGE;
 314        *res = tmp;
 315        return 0;
 316}
 317EXPORT_SYMBOL(kstrtos8);
 318
 319/**
 320 * kstrtobool - convert common user inputs into boolean values
 321 * @s: input string
 322 * @res: result
 323 *
 324 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
 325 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
 326 * pointed to by res is updated upon finding a match.
 327 */
 328int kstrtobool(const char *s, bool *res)
 329{
 330        if (!s)
 331                return -EINVAL;
 332
 333        switch (s[0]) {
 334        case 'y':
 335        case 'Y':
 336        case '1':
 337                *res = true;
 338                return 0;
 339        case 'n':
 340        case 'N':
 341        case '0':
 342                *res = false;
 343                return 0;
 344        case 'o':
 345        case 'O':
 346                switch (s[1]) {
 347                case 'n':
 348                case 'N':
 349                        *res = true;
 350                        return 0;
 351                case 'f':
 352                case 'F':
 353                        *res = false;
 354                        return 0;
 355                default:
 356                        break;
 357                }
 358                break;
 359        default:
 360                break;
 361        }
 362
 363        return -EINVAL;
 364}
 365EXPORT_SYMBOL(kstrtobool);
 366
 367/*
 368 * Since "base" would be a nonsense argument, this open-codes the
 369 * _from_user helper instead of using the helper macro below.
 370 */
 371int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
 372{
 373        /* Longest string needed to differentiate, newline, terminator */
 374        char buf[4];
 375
 376        count = min(count, sizeof(buf) - 1);
 377        if (copy_from_user(buf, s, count))
 378                return -EFAULT;
 379        buf[count] = '\0';
 380        return kstrtobool(buf, res);
 381}
 382EXPORT_SYMBOL(kstrtobool_from_user);
 383
 384#define kstrto_from_user(f, g, type)                                    \
 385int f(const char __user *s, size_t count, unsigned int base, type *res) \
 386{                                                                       \
 387        /* sign, base 2 representation, newline, terminator */          \
 388        char buf[1 + sizeof(type) * 8 + 1 + 1];                         \
 389                                                                        \
 390        count = min(count, sizeof(buf) - 1);                            \
 391        if (copy_from_user(buf, s, count))                              \
 392                return -EFAULT;                                         \
 393        buf[count] = '\0';                                              \
 394        return g(buf, base, res);                                       \
 395}                                                                       \
 396EXPORT_SYMBOL(f)
 397
 398kstrto_from_user(kstrtoull_from_user,   kstrtoull,      unsigned long long);
 399kstrto_from_user(kstrtoll_from_user,    kstrtoll,       long long);
 400kstrto_from_user(kstrtoul_from_user,    kstrtoul,       unsigned long);
 401kstrto_from_user(kstrtol_from_user,     kstrtol,        long);
 402kstrto_from_user(kstrtouint_from_user,  kstrtouint,     unsigned int);
 403kstrto_from_user(kstrtoint_from_user,   kstrtoint,      int);
 404kstrto_from_user(kstrtou16_from_user,   kstrtou16,      u16);
 405kstrto_from_user(kstrtos16_from_user,   kstrtos16,      s16);
 406kstrto_from_user(kstrtou8_from_user,    kstrtou8,       u8);
 407kstrto_from_user(kstrtos8_from_user,    kstrtos8,       s8);
 408