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/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 25 const char *_parse_integer_fixup_radix(const char *s, unsigned int *base) 26 { 27 if (*base == 0) { 28 if (s[0] == '0') { 29 if (_tolower(s[1]) == 'x' && isxdigit(s[2])) 30 *base = 16; 31 else 32 *base = 8; 33 } else 34 *base = 10; 35 } 36 if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x') 37 s += 2; 38 return s; 39 } 40 41 /* 42 * Convert non-negative integer string representation in explicitly given radix 43 * to an integer. A maximum of max_chars characters will be converted. 44 * 45 * Return number of characters consumed maybe or-ed with overflow bit. 46 * If overflow occurs, result integer (incorrect) is still returned. 47 * 48 * Don't you dare use this function. 49 */ 50 unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p, 51 size_t max_chars) 52 { 53 unsigned long long res; 54 unsigned int rv; 55 56 res = 0; 57 rv = 0; 58 while (max_chars--) { 59 unsigned int c = *s; 60 unsigned int lc = c | 0x20; /* don't tolower() this line */ 61 unsigned int val; 62 63 if ('0' <= c && c <= '9') 64 val = c - '0'; 65 else if ('a' <= lc && lc <= 'f') 66 val = lc - 'a' + 10; 67 else 68 break; 69 70 if (val >= base) 71 break; 72 /* 73 * Check for overflow only if we are within range of 74 * it in the max base we support (16) 75 */ 76 if (unlikely(res & (~0ull << 60))) { 77 if (res > div_u64(ULLONG_MAX - val, base)) 78 rv |= KSTRTOX_OVERFLOW; 79 } 80 res = res * base + val; 81 rv++; 82 s++; 83 } 84 *p = res; 85 return rv; 86 } 87 88 unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p) 89 { 90 return _parse_integer_limit(s, base, p, INT_MAX); 91 } 92 93 static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res) 94 { 95 unsigned long long _res; 96 unsigned int rv; 97 98 s = _parse_integer_fixup_radix(s, &base); 99 rv = _parse_integer(s, base, &_res); 100 if (rv & KSTRTOX_OVERFLOW) 101 return -ERANGE; 102 if (rv == 0) 103 return -EINVAL; 104 s += rv; 105 if (*s == '\n') 106 s++; 107 if (*s) 108 return -EINVAL; 109 *res = _res; 110 return 0; 111 } 112 113 /** 114 * kstrtoull - convert a string to an unsigned long long 115 * @s: The start of the string. The string must be null-terminated, and may also 116 * include a single newline before its terminating null. The first character 117 * may also be a plus sign, but not a minus sign. 118 * @base: The number base to use. The maximum supported base is 16. If base is 119 * given as 0, then the base of the string is automatically detected with the 120 * conventional semantics - If it begins with 0x the number will be parsed as a 121 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 122 * parsed as an octal number. Otherwise it will be parsed as a decimal. 123 * @res: Where to write the result of the conversion on success. 124 * 125 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 126 * Preferred over simple_strtoull(). Return code must be checked. 127 */ 128 int kstrtoull(const char *s, unsigned int base, unsigned long long *res) 129 { 130 if (s[0] == '+') 131 s++; 132 return _kstrtoull(s, base, res); 133 } 134 EXPORT_SYMBOL(kstrtoull); 135 136 /** 137 * kstrtoll - convert a string to a long long 138 * @s: The start of the string. The string must be null-terminated, and may also 139 * include a single newline before its terminating null. The first character 140 * may also be a plus sign or a minus sign. 141 * @base: The number base to use. The maximum supported base is 16. If base is 142 * given as 0, then the base of the string is automatically detected with the 143 * conventional semantics - If it begins with 0x the number will be parsed as a 144 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 145 * parsed as an octal number. Otherwise it will be parsed as a decimal. 146 * @res: Where to write the result of the conversion on success. 147 * 148 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 149 * Preferred over simple_strtoll(). Return code must be checked. 150 */ 151 int kstrtoll(const char *s, unsigned int base, long long *res) 152 { 153 unsigned long long tmp; 154 int rv; 155 156 if (s[0] == '-') { 157 rv = _kstrtoull(s + 1, base, &tmp); 158 if (rv < 0) 159 return rv; 160 if ((long long)-tmp > 0) 161 return -ERANGE; 162 *res = -tmp; 163 } else { 164 rv = kstrtoull(s, base, &tmp); 165 if (rv < 0) 166 return rv; 167 if ((long long)tmp < 0) 168 return -ERANGE; 169 *res = tmp; 170 } 171 return 0; 172 } 173 EXPORT_SYMBOL(kstrtoll); 174 175 /* Internal, do not use. */ 176 int _kstrtoul(const char *s, unsigned int base, unsigned long *res) 177 { 178 unsigned long long tmp; 179 int rv; 180 181 rv = kstrtoull(s, base, &tmp); 182 if (rv < 0) 183 return rv; 184 if (tmp != (unsigned long)tmp) 185 return -ERANGE; 186 *res = tmp; 187 return 0; 188 } 189 EXPORT_SYMBOL(_kstrtoul); 190 191 /* Internal, do not use. */ 192 int _kstrtol(const char *s, unsigned int base, long *res) 193 { 194 long long tmp; 195 int rv; 196 197 rv = kstrtoll(s, base, &tmp); 198 if (rv < 0) 199 return rv; 200 if (tmp != (long)tmp) 201 return -ERANGE; 202 *res = tmp; 203 return 0; 204 } 205 EXPORT_SYMBOL(_kstrtol); 206 207 /** 208 * kstrtouint - convert a string to an unsigned int 209 * @s: The start of the string. The string must be null-terminated, and may also 210 * include a single newline before its terminating null. The first character 211 * may also be a plus sign, but not a minus sign. 212 * @base: The number base to use. The maximum supported base is 16. If base is 213 * given as 0, then the base of the string is automatically detected with the 214 * conventional semantics - If it begins with 0x the number will be parsed as a 215 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 216 * parsed as an octal number. Otherwise it will be parsed as a decimal. 217 * @res: Where to write the result of the conversion on success. 218 * 219 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 220 * Preferred over simple_strtoul(). Return code must be checked. 221 */ 222 int kstrtouint(const char *s, unsigned int base, unsigned int *res) 223 { 224 unsigned long long tmp; 225 int rv; 226 227 rv = kstrtoull(s, base, &tmp); 228 if (rv < 0) 229 return rv; 230 if (tmp != (unsigned int)tmp) 231 return -ERANGE; 232 *res = tmp; 233 return 0; 234 } 235 EXPORT_SYMBOL(kstrtouint); 236 237 /** 238 * kstrtoint - convert a string to an int 239 * @s: The start of the string. The string must be null-terminated, and may also 240 * include a single newline before its terminating null. The first character 241 * may also be a plus sign or a minus sign. 242 * @base: The number base to use. The maximum supported base is 16. If base is 243 * given as 0, then the base of the string is automatically detected with the 244 * conventional semantics - If it begins with 0x the number will be parsed as a 245 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 246 * parsed as an octal number. Otherwise it will be parsed as a decimal. 247 * @res: Where to write the result of the conversion on success. 248 * 249 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 250 * Preferred over simple_strtol(). Return code must be checked. 251 */ 252 int kstrtoint(const char *s, unsigned int base, int *res) 253 { 254 long long tmp; 255 int rv; 256 257 rv = kstrtoll(s, base, &tmp); 258 if (rv < 0) 259 return rv; 260 if (tmp != (int)tmp) 261 return -ERANGE; 262 *res = tmp; 263 return 0; 264 } 265 EXPORT_SYMBOL(kstrtoint); 266 267 int kstrtou16(const char *s, unsigned int base, u16 *res) 268 { 269 unsigned long long tmp; 270 int rv; 271 272 rv = kstrtoull(s, base, &tmp); 273 if (rv < 0) 274 return rv; 275 if (tmp != (u16)tmp) 276 return -ERANGE; 277 *res = tmp; 278 return 0; 279 } 280 EXPORT_SYMBOL(kstrtou16); 281 282 int kstrtos16(const char *s, unsigned int base, s16 *res) 283 { 284 long long tmp; 285 int rv; 286 287 rv = kstrtoll(s, base, &tmp); 288 if (rv < 0) 289 return rv; 290 if (tmp != (s16)tmp) 291 return -ERANGE; 292 *res = tmp; 293 return 0; 294 } 295 EXPORT_SYMBOL(kstrtos16); 296 297 int kstrtou8(const char *s, unsigned int base, u8 *res) 298 { 299 unsigned long long tmp; 300 int rv; 301 302 rv = kstrtoull(s, base, &tmp); 303 if (rv < 0) 304 return rv; 305 if (tmp != (u8)tmp) 306 return -ERANGE; 307 *res = tmp; 308 return 0; 309 } 310 EXPORT_SYMBOL(kstrtou8); 311 312 int kstrtos8(const char *s, unsigned int base, s8 *res) 313 { 314 long long tmp; 315 int rv; 316 317 rv = kstrtoll(s, base, &tmp); 318 if (rv < 0) 319 return rv; 320 if (tmp != (s8)tmp) 321 return -ERANGE; 322 *res = tmp; 323 return 0; 324 } 325 EXPORT_SYMBOL(kstrtos8); 326 327 /** 328 * kstrtobool - convert common user inputs into boolean values 329 * @s: input string 330 * @res: result 331 * 332 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or 333 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value 334 * pointed to by res is updated upon finding a match. 335 */ 336 int kstrtobool(const char *s, bool *res) 337 { 338 if (!s) 339 return -EINVAL; 340 341 switch (s[0]) { 342 case 'y': 343 case 'Y': 344 case '1': 345 *res = true; 346 return 0; 347 case 'n': 348 case 'N': 349 case '0': 350 *res = false; 351 return 0; 352 case 'o': 353 case 'O': 354 switch (s[1]) { 355 case 'n': 356 case 'N': 357 *res = true; 358 return 0; 359 case 'f': 360 case 'F': 361 *res = false; 362 return 0; 363 default: 364 break; 365 } 366 break; 367 default: 368 break; 369 } 370 371 return -EINVAL; 372 } 373 EXPORT_SYMBOL(kstrtobool); 374 375 /* 376 * Since "base" would be a nonsense argument, this open-codes the 377 * _from_user helper instead of using the helper macro below. 378 */ 379 int kstrtobool_from_user(const char __user *s, size_t count, bool *res) 380 { 381 /* Longest string needed to differentiate, newline, terminator */ 382 char buf[4]; 383 384 count = min(count, sizeof(buf) - 1); 385 if (copy_from_user(buf, s, count)) 386 return -EFAULT; 387 buf[count] = '\0'; 388 return kstrtobool(buf, res); 389 } 390 EXPORT_SYMBOL(kstrtobool_from_user); 391 392 #define kstrto_from_user(f, g, type) \ 393 int f(const char __user *s, size_t count, unsigned int base, type *res) \ 394 { \ 395 /* sign, base 2 representation, newline, terminator */ \ 396 char buf[1 + sizeof(type) * 8 + 1 + 1]; \ 397 \ 398 count = min(count, sizeof(buf) - 1); \ 399 if (copy_from_user(buf, s, count)) \ 400 return -EFAULT; \ 401 buf[count] = '\0'; \ 402 return g(buf, base, res); \ 403 } \ 404 EXPORT_SYMBOL(f) 405 406 kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long); 407 kstrto_from_user(kstrtoll_from_user, kstrtoll, long long); 408 kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long); 409 kstrto_from_user(kstrtol_from_user, kstrtol, long); 410 kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int); 411 kstrto_from_user(kstrtoint_from_user, kstrtoint, int); 412 kstrto_from_user(kstrtou16_from_user, kstrtou16, u16); 413 kstrto_from_user(kstrtos16_from_user, kstrtos16, s16); 414 kstrto_from_user(kstrtou8_from_user, kstrtou8, u8); 415 kstrto_from_user(kstrtos8_from_user, kstrtos8, s8); 416