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 24 const 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 */ 48 unsigned 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 85 static 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 * Used as a replacement for the obsolete simple_strtoull. Return code must 119 * be checked. 120 */ 121 int kstrtoull(const char *s, unsigned int base, unsigned long long *res) 122 { 123 if (s[0] == '+') 124 s++; 125 return _kstrtoull(s, base, res); 126 } 127 EXPORT_SYMBOL(kstrtoull); 128 129 /** 130 * kstrtoll - convert a string to a long long 131 * @s: The start of the string. The string must be null-terminated, and may also 132 * include a single newline before its terminating null. The first character 133 * may also be a plus sign or a minus sign. 134 * @base: The number base to use. The maximum supported base is 16. If base is 135 * given as 0, then the base of the string is automatically detected with the 136 * conventional semantics - If it begins with 0x the number will be parsed as a 137 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 138 * parsed as an octal number. Otherwise it will be parsed as a decimal. 139 * @res: Where to write the result of the conversion on success. 140 * 141 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 142 * Used as a replacement for the obsolete simple_strtoull. Return code must 143 * be checked. 144 */ 145 int kstrtoll(const char *s, unsigned int base, long long *res) 146 { 147 unsigned long long tmp; 148 int rv; 149 150 if (s[0] == '-') { 151 rv = _kstrtoull(s + 1, base, &tmp); 152 if (rv < 0) 153 return rv; 154 if ((long long)-tmp > 0) 155 return -ERANGE; 156 *res = -tmp; 157 } else { 158 rv = kstrtoull(s, base, &tmp); 159 if (rv < 0) 160 return rv; 161 if ((long long)tmp < 0) 162 return -ERANGE; 163 *res = tmp; 164 } 165 return 0; 166 } 167 EXPORT_SYMBOL(kstrtoll); 168 169 /* Internal, do not use. */ 170 int _kstrtoul(const char *s, unsigned int base, unsigned long *res) 171 { 172 unsigned long long tmp; 173 int rv; 174 175 rv = kstrtoull(s, base, &tmp); 176 if (rv < 0) 177 return rv; 178 if (tmp != (unsigned long)tmp) 179 return -ERANGE; 180 *res = tmp; 181 return 0; 182 } 183 EXPORT_SYMBOL(_kstrtoul); 184 185 /* Internal, do not use. */ 186 int _kstrtol(const char *s, unsigned int base, long *res) 187 { 188 long long tmp; 189 int rv; 190 191 rv = kstrtoll(s, base, &tmp); 192 if (rv < 0) 193 return rv; 194 if (tmp != (long)tmp) 195 return -ERANGE; 196 *res = tmp; 197 return 0; 198 } 199 EXPORT_SYMBOL(_kstrtol); 200 201 /** 202 * kstrtouint - convert a string to an unsigned int 203 * @s: The start of the string. The string must be null-terminated, and may also 204 * include a single newline before its terminating null. The first character 205 * may also be a plus sign, but not a minus sign. 206 * @base: The number base to use. The maximum supported base is 16. If base is 207 * given as 0, then the base of the string is automatically detected with the 208 * conventional semantics - If it begins with 0x the number will be parsed as a 209 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 210 * parsed as an octal number. Otherwise it will be parsed as a decimal. 211 * @res: Where to write the result of the conversion on success. 212 * 213 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 214 * Used as a replacement for the obsolete simple_strtoull. Return code must 215 * be checked. 216 */ 217 int kstrtouint(const char *s, unsigned int base, unsigned int *res) 218 { 219 unsigned long long tmp; 220 int rv; 221 222 rv = kstrtoull(s, base, &tmp); 223 if (rv < 0) 224 return rv; 225 if (tmp != (unsigned int)tmp) 226 return -ERANGE; 227 *res = tmp; 228 return 0; 229 } 230 EXPORT_SYMBOL(kstrtouint); 231 232 /** 233 * kstrtoint - convert a string to an int 234 * @s: The start of the string. The string must be null-terminated, and may also 235 * include a single newline before its terminating null. The first character 236 * may also be a plus sign or a minus sign. 237 * @base: The number base to use. The maximum supported base is 16. If base is 238 * given as 0, then the base of the string is automatically detected with the 239 * conventional semantics - If it begins with 0x the number will be parsed as a 240 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 241 * parsed as an octal number. Otherwise it will be parsed as a decimal. 242 * @res: Where to write the result of the conversion on success. 243 * 244 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 245 * Used as a replacement for the obsolete simple_strtoull. Return code must 246 * be checked. 247 */ 248 int kstrtoint(const char *s, unsigned int base, int *res) 249 { 250 long long tmp; 251 int rv; 252 253 rv = kstrtoll(s, base, &tmp); 254 if (rv < 0) 255 return rv; 256 if (tmp != (int)tmp) 257 return -ERANGE; 258 *res = tmp; 259 return 0; 260 } 261 EXPORT_SYMBOL(kstrtoint); 262 263 int kstrtou16(const char *s, unsigned int base, u16 *res) 264 { 265 unsigned long long tmp; 266 int rv; 267 268 rv = kstrtoull(s, base, &tmp); 269 if (rv < 0) 270 return rv; 271 if (tmp != (u16)tmp) 272 return -ERANGE; 273 *res = tmp; 274 return 0; 275 } 276 EXPORT_SYMBOL(kstrtou16); 277 278 int kstrtos16(const char *s, unsigned int base, s16 *res) 279 { 280 long long tmp; 281 int rv; 282 283 rv = kstrtoll(s, base, &tmp); 284 if (rv < 0) 285 return rv; 286 if (tmp != (s16)tmp) 287 return -ERANGE; 288 *res = tmp; 289 return 0; 290 } 291 EXPORT_SYMBOL(kstrtos16); 292 293 int kstrtou8(const char *s, unsigned int base, u8 *res) 294 { 295 unsigned long long tmp; 296 int rv; 297 298 rv = kstrtoull(s, base, &tmp); 299 if (rv < 0) 300 return rv; 301 if (tmp != (u8)tmp) 302 return -ERANGE; 303 *res = tmp; 304 return 0; 305 } 306 EXPORT_SYMBOL(kstrtou8); 307 308 int kstrtos8(const char *s, unsigned int base, s8 *res) 309 { 310 long long tmp; 311 int rv; 312 313 rv = kstrtoll(s, base, &tmp); 314 if (rv < 0) 315 return rv; 316 if (tmp != (s8)tmp) 317 return -ERANGE; 318 *res = tmp; 319 return 0; 320 } 321 EXPORT_SYMBOL(kstrtos8); 322 323 /** 324 * kstrtobool - convert common user inputs into boolean values 325 * @s: input string 326 * @res: result 327 * 328 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or 329 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value 330 * pointed to by res is updated upon finding a match. 331 */ 332 int kstrtobool(const char *s, bool *res) 333 { 334 if (!s) 335 return -EINVAL; 336 337 switch (s[0]) { 338 case 'y': 339 case 'Y': 340 case '1': 341 *res = true; 342 return 0; 343 case 'n': 344 case 'N': 345 case '0': 346 *res = false; 347 return 0; 348 case 'o': 349 case 'O': 350 switch (s[1]) { 351 case 'n': 352 case 'N': 353 *res = true; 354 return 0; 355 case 'f': 356 case 'F': 357 *res = false; 358 return 0; 359 default: 360 break; 361 } 362 default: 363 break; 364 } 365 366 return -EINVAL; 367 } 368 EXPORT_SYMBOL(kstrtobool); 369 370 /* 371 * Since "base" would be a nonsense argument, this open-codes the 372 * _from_user helper instead of using the helper macro below. 373 */ 374 int kstrtobool_from_user(const char __user *s, size_t count, bool *res) 375 { 376 /* Longest string needed to differentiate, newline, terminator */ 377 char buf[4]; 378 379 count = min(count, sizeof(buf) - 1); 380 if (copy_from_user(buf, s, count)) 381 return -EFAULT; 382 buf[count] = '\0'; 383 return kstrtobool(buf, res); 384 } 385 EXPORT_SYMBOL(kstrtobool_from_user); 386 387 #define kstrto_from_user(f, g, type) \ 388 int f(const char __user *s, size_t count, unsigned int base, type *res) \ 389 { \ 390 /* sign, base 2 representation, newline, terminator */ \ 391 char buf[1 + sizeof(type) * 8 + 1 + 1]; \ 392 \ 393 count = min(count, sizeof(buf) - 1); \ 394 if (copy_from_user(buf, s, count)) \ 395 return -EFAULT; \ 396 buf[count] = '\0'; \ 397 return g(buf, base, res); \ 398 } \ 399 EXPORT_SYMBOL(f) 400 401 kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long); 402 kstrto_from_user(kstrtoll_from_user, kstrtoll, long long); 403 kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long); 404 kstrto_from_user(kstrtol_from_user, kstrtol, long); 405 kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int); 406 kstrto_from_user(kstrtoint_from_user, kstrtoint, int); 407 kstrto_from_user(kstrtou16_from_user, kstrtou16, u16); 408 kstrto_from_user(kstrtos16_from_user, kstrtos16, s16); 409 kstrto_from_user(kstrtou8_from_user, kstrtou8, u8); 410 kstrto_from_user(kstrtos8_from_user, kstrtos8, s8); 411