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1// SPDX-License-Identifier: GPL-2.02/*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/export.h>18#include <linux/kstrtox.h>19#include <linux/math64.h>20#include <linux/types.h>21#include <linux/uaccess.h>22 23#include "kstrtox.h"24 25noinline26const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)27{28 if (*base == 0) {29 if (s[0] == '0') {30 if (_tolower(s[1]) == 'x' && isxdigit(s[2]))31 *base = 16;32 else33 *base = 8;34 } else35 *base = 10;36 }37 if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')38 s += 2;39 return s;40}41 42/*43 * Convert non-negative integer string representation in explicitly given radix44 * to an integer. A maximum of max_chars characters will be converted.45 *46 * Return number of characters consumed maybe or-ed with overflow bit.47 * If overflow occurs, result integer (incorrect) is still returned.48 *49 * Don't you dare use this function.50 */51noinline52unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,53 size_t max_chars)54{55 unsigned long long res;56 unsigned int rv;57 58 res = 0;59 rv = 0;60 while (max_chars--) {61 unsigned int c = *s;62 unsigned int lc = _tolower(c);63 unsigned int val;64 65 if ('0' <= c && c <= '9')66 val = c - '0';67 else if ('a' <= lc && lc <= 'f')68 val = lc - 'a' + 10;69 else70 break;71 72 if (val >= base)73 break;74 /*75 * Check for overflow only if we are within range of76 * it in the max base we support (16)77 */78 if (unlikely(res & (~0ull << 60))) {79 if (res > div_u64(ULLONG_MAX - val, base))80 rv |= KSTRTOX_OVERFLOW;81 }82 res = res * base + val;83 rv++;84 s++;85 }86 *p = res;87 return rv;88}89 90noinline91unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)92{93 return _parse_integer_limit(s, base, p, INT_MAX);94}95 96static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)97{98 unsigned long long _res;99 unsigned int rv;100 101 s = _parse_integer_fixup_radix(s, &base);102 rv = _parse_integer(s, base, &_res);103 if (rv & KSTRTOX_OVERFLOW)104 return -ERANGE;105 if (rv == 0)106 return -EINVAL;107 s += rv;108 if (*s == '\n')109 s++;110 if (*s)111 return -EINVAL;112 *res = _res;113 return 0;114}115 116/**117 * kstrtoull - convert a string to an unsigned long long118 * @s: The start of the string. The string must be null-terminated, and may also119 * include a single newline before its terminating null. The first character120 * may also be a plus sign, but not a minus sign.121 * @base: The number base to use. The maximum supported base is 16. If base is122 * given as 0, then the base of the string is automatically detected with the123 * conventional semantics - If it begins with 0x the number will be parsed as a124 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be125 * parsed as an octal number. Otherwise it will be parsed as a decimal.126 * @res: Where to write the result of the conversion on success.127 *128 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.129 * Preferred over simple_strtoull(). Return code must be checked.130 */131noinline132int kstrtoull(const char *s, unsigned int base, unsigned long long *res)133{134 if (s[0] == '+')135 s++;136 return _kstrtoull(s, base, res);137}138EXPORT_SYMBOL(kstrtoull);139 140/**141 * kstrtoll - convert a string to a long long142 * @s: The start of the string. The string must be null-terminated, and may also143 * include a single newline before its terminating null. The first character144 * may also be a plus sign or a minus sign.145 * @base: The number base to use. The maximum supported base is 16. If base is146 * given as 0, then the base of the string is automatically detected with the147 * conventional semantics - If it begins with 0x the number will be parsed as a148 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be149 * parsed as an octal number. Otherwise it will be parsed as a decimal.150 * @res: Where to write the result of the conversion on success.151 *152 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.153 * Preferred over simple_strtoll(). Return code must be checked.154 */155noinline156int kstrtoll(const char *s, unsigned int base, long long *res)157{158 unsigned long long tmp;159 int rv;160 161 if (s[0] == '-') {162 rv = _kstrtoull(s + 1, base, &tmp);163 if (rv < 0)164 return rv;165 if ((long long)-tmp > 0)166 return -ERANGE;167 *res = -tmp;168 } else {169 rv = kstrtoull(s, base, &tmp);170 if (rv < 0)171 return rv;172 if ((long long)tmp < 0)173 return -ERANGE;174 *res = tmp;175 }176 return 0;177}178EXPORT_SYMBOL(kstrtoll);179 180/* Internal, do not use. */181int _kstrtoul(const char *s, unsigned int base, unsigned long *res)182{183 unsigned long long tmp;184 int rv;185 186 rv = kstrtoull(s, base, &tmp);187 if (rv < 0)188 return rv;189 if (tmp != (unsigned long)tmp)190 return -ERANGE;191 *res = tmp;192 return 0;193}194EXPORT_SYMBOL(_kstrtoul);195 196/* Internal, do not use. */197int _kstrtol(const char *s, unsigned int base, long *res)198{199 long long tmp;200 int rv;201 202 rv = kstrtoll(s, base, &tmp);203 if (rv < 0)204 return rv;205 if (tmp != (long)tmp)206 return -ERANGE;207 *res = tmp;208 return 0;209}210EXPORT_SYMBOL(_kstrtol);211 212/**213 * kstrtouint - convert a string to an unsigned int214 * @s: The start of the string. The string must be null-terminated, and may also215 * include a single newline before its terminating null. The first character216 * may also be a plus sign, but not a minus sign.217 * @base: The number base to use. The maximum supported base is 16. If base is218 * given as 0, then the base of the string is automatically detected with the219 * conventional semantics - If it begins with 0x the number will be parsed as a220 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be221 * parsed as an octal number. Otherwise it will be parsed as a decimal.222 * @res: Where to write the result of the conversion on success.223 *224 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.225 * Preferred over simple_strtoul(). Return code must be checked.226 */227noinline228int kstrtouint(const char *s, unsigned int base, unsigned int *res)229{230 unsigned long long tmp;231 int rv;232 233 rv = kstrtoull(s, base, &tmp);234 if (rv < 0)235 return rv;236 if (tmp != (unsigned int)tmp)237 return -ERANGE;238 *res = tmp;239 return 0;240}241EXPORT_SYMBOL(kstrtouint);242 243/**244 * kstrtoint - convert a string to an int245 * @s: The start of the string. The string must be null-terminated, and may also246 * include a single newline before its terminating null. The first character247 * may also be a plus sign or a minus sign.248 * @base: The number base to use. The maximum supported base is 16. If base is249 * given as 0, then the base of the string is automatically detected with the250 * conventional semantics - If it begins with 0x the number will be parsed as a251 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be252 * parsed as an octal number. Otherwise it will be parsed as a decimal.253 * @res: Where to write the result of the conversion on success.254 *255 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.256 * Preferred over simple_strtol(). Return code must be checked.257 */258noinline259int kstrtoint(const char *s, unsigned int base, int *res)260{261 long long tmp;262 int rv;263 264 rv = kstrtoll(s, base, &tmp);265 if (rv < 0)266 return rv;267 if (tmp != (int)tmp)268 return -ERANGE;269 *res = tmp;270 return 0;271}272EXPORT_SYMBOL(kstrtoint);273 274noinline275int kstrtou16(const char *s, unsigned int base, u16 *res)276{277 unsigned long long tmp;278 int rv;279 280 rv = kstrtoull(s, base, &tmp);281 if (rv < 0)282 return rv;283 if (tmp != (u16)tmp)284 return -ERANGE;285 *res = tmp;286 return 0;287}288EXPORT_SYMBOL(kstrtou16);289 290noinline291int kstrtos16(const char *s, unsigned int base, s16 *res)292{293 long long tmp;294 int rv;295 296 rv = kstrtoll(s, base, &tmp);297 if (rv < 0)298 return rv;299 if (tmp != (s16)tmp)300 return -ERANGE;301 *res = tmp;302 return 0;303}304EXPORT_SYMBOL(kstrtos16);305 306noinline307int kstrtou8(const char *s, unsigned int base, u8 *res)308{309 unsigned long long tmp;310 int rv;311 312 rv = kstrtoull(s, base, &tmp);313 if (rv < 0)314 return rv;315 if (tmp != (u8)tmp)316 return -ERANGE;317 *res = tmp;318 return 0;319}320EXPORT_SYMBOL(kstrtou8);321 322noinline323int kstrtos8(const char *s, unsigned int base, s8 *res)324{325 long long tmp;326 int rv;327 328 rv = kstrtoll(s, base, &tmp);329 if (rv < 0)330 return rv;331 if (tmp != (s8)tmp)332 return -ERANGE;333 *res = tmp;334 return 0;335}336EXPORT_SYMBOL(kstrtos8);337 338/**339 * kstrtobool - convert common user inputs into boolean values340 * @s: input string341 * @res: result342 *343 * This routine returns 0 iff the first character is one of 'YyTt1NnFf0', or344 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value345 * pointed to by res is updated upon finding a match.346 */347noinline348int kstrtobool(const char *s, bool *res)349{350 if (!s)351 return -EINVAL;352 353 switch (s[0]) {354 case 'y':355 case 'Y':356 case 't':357 case 'T':358 case '1':359 *res = true;360 return 0;361 case 'n':362 case 'N':363 case 'f':364 case 'F':365 case '0':366 *res = false;367 return 0;368 case 'o':369 case 'O':370 switch (s[1]) {371 case 'n':372 case 'N':373 *res = true;374 return 0;375 case 'f':376 case 'F':377 *res = false;378 return 0;379 default:380 break;381 }382 break;383 default:384 break;385 }386 387 return -EINVAL;388}389EXPORT_SYMBOL(kstrtobool);390 391/*392 * Since "base" would be a nonsense argument, this open-codes the393 * _from_user helper instead of using the helper macro below.394 */395int kstrtobool_from_user(const char __user *s, size_t count, bool *res)396{397 /* Longest string needed to differentiate, newline, terminator */398 char buf[4];399 400 count = min(count, sizeof(buf) - 1);401 if (copy_from_user(buf, s, count))402 return -EFAULT;403 buf[count] = '\0';404 return kstrtobool(buf, res);405}406EXPORT_SYMBOL(kstrtobool_from_user);407 408#define kstrto_from_user(f, g, type) \409int f(const char __user *s, size_t count, unsigned int base, type *res) \410{ \411 /* sign, base 2 representation, newline, terminator */ \412 char buf[1 + sizeof(type) * 8 + 1 + 1]; \413 \414 count = min(count, sizeof(buf) - 1); \415 if (copy_from_user(buf, s, count)) \416 return -EFAULT; \417 buf[count] = '\0'; \418 return g(buf, base, res); \419} \420EXPORT_SYMBOL(f)421 422kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long);423kstrto_from_user(kstrtoll_from_user, kstrtoll, long long);424kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long);425kstrto_from_user(kstrtol_from_user, kstrtol, long);426kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int);427kstrto_from_user(kstrtoint_from_user, kstrtoint, int);428kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);429kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);430kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);431kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);432