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/export.h> 19 #include <linux/types.h> 20 #include <linux/uaccess.h> 21 #include "kstrtox.h" 22 23 const 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 */ 47 unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p) 48 { 49 unsigned long long res; 50 unsigned int rv; 51 52 res = 0; 53 rv = 0; 54 while (1) { 55 unsigned int c = *s; 56 unsigned int lc = c | 0x20; /* don't tolower() this line */ 57 unsigned int val; 58 59 if ('0' <= c && c <= '9') 60 val = c - '0'; 61 else if ('a' <= lc && lc <= 'f') 62 val = lc - 'a' + 10; 63 else 64 break; 65 66 if (val >= base) 67 break; 68 /* 69 * Check for overflow only if we are within range of 70 * it in the max base we support (16) 71 */ 72 if (unlikely(res & (~0ull << 60))) { 73 if (res > div_u64(ULLONG_MAX - val, base)) 74 rv |= KSTRTOX_OVERFLOW; 75 } 76 res = res * base + val; 77 rv++; 78 s++; 79 } 80 *p = res; 81 return rv; 82 } 83 84 static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res) 85 { 86 unsigned long long _res; 87 unsigned int rv; 88 89 s = _parse_integer_fixup_radix(s, &base); 90 rv = _parse_integer(s, base, &_res); 91 if (rv & KSTRTOX_OVERFLOW) 92 return -ERANGE; 93 if (rv == 0) 94 return -EINVAL; 95 s += rv; 96 if (*s == '\n') 97 s++; 98 if (*s) 99 return -EINVAL; 100 *res = _res; 101 return 0; 102 } 103 104 /** 105 * kstrtoull - convert a string to an unsigned long long 106 * @s: The start of the string. The string must be null-terminated, and may also 107 * include a single newline before its terminating null. The first character 108 * may also be a plus sign, but not a minus sign. 109 * @base: The number base to use. The maximum supported base is 16. If base is 110 * given as 0, then the base of the string is automatically detected with the 111 * conventional semantics - If it begins with 0x the number will be parsed as a 112 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 113 * parsed as an octal number. Otherwise it will be parsed as a decimal. 114 * @res: Where to write the result of the conversion on success. 115 * 116 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 117 * Used as a replacement for the obsolete simple_strtoull. Return code must 118 * be checked. 119 */ 120 int 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 } 126 EXPORT_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 * Used as a replacement for the obsolete simple_strtoull. Return code must 142 * be checked. 143 */ 144 int kstrtoll(const char *s, unsigned int base, long long *res) 145 { 146 unsigned long long tmp; 147 int rv; 148 149 if (s[0] == '-') { 150 rv = _kstrtoull(s + 1, base, &tmp); 151 if (rv < 0) 152 return rv; 153 if ((long long)-tmp > 0) 154 return -ERANGE; 155 *res = -tmp; 156 } else { 157 rv = kstrtoull(s, base, &tmp); 158 if (rv < 0) 159 return rv; 160 if ((long long)tmp < 0) 161 return -ERANGE; 162 *res = tmp; 163 } 164 return 0; 165 } 166 EXPORT_SYMBOL(kstrtoll); 167 168 /* Internal, do not use. */ 169 int _kstrtoul(const char *s, unsigned int base, unsigned long *res) 170 { 171 unsigned long long tmp; 172 int rv; 173 174 rv = kstrtoull(s, base, &tmp); 175 if (rv < 0) 176 return rv; 177 if (tmp != (unsigned long long)(unsigned long)tmp) 178 return -ERANGE; 179 *res = tmp; 180 return 0; 181 } 182 EXPORT_SYMBOL(_kstrtoul); 183 184 /* Internal, do not use. */ 185 int _kstrtol(const char *s, unsigned int base, long *res) 186 { 187 long long tmp; 188 int rv; 189 190 rv = kstrtoll(s, base, &tmp); 191 if (rv < 0) 192 return rv; 193 if (tmp != (long long)(long)tmp) 194 return -ERANGE; 195 *res = tmp; 196 return 0; 197 } 198 EXPORT_SYMBOL(_kstrtol); 199 200 /** 201 * kstrtouint - convert a string to an unsigned int 202 * @s: The start of the string. The string must be null-terminated, and may also 203 * include a single newline before its terminating null. The first character 204 * may also be a plus sign, but not a minus sign. 205 * @base: The number base to use. The maximum supported base is 16. If base is 206 * given as 0, then the base of the string is automatically detected with the 207 * conventional semantics - If it begins with 0x the number will be parsed as a 208 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 209 * parsed as an octal number. Otherwise it will be parsed as a decimal. 210 * @res: Where to write the result of the conversion on success. 211 * 212 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 213 * Used as a replacement for the obsolete simple_strtoull. Return code must 214 * be checked. 215 */ 216 int kstrtouint(const char *s, unsigned int base, unsigned int *res) 217 { 218 unsigned long long tmp; 219 int rv; 220 221 rv = kstrtoull(s, base, &tmp); 222 if (rv < 0) 223 return rv; 224 if (tmp != (unsigned long long)(unsigned int)tmp) 225 return -ERANGE; 226 *res = tmp; 227 return 0; 228 } 229 EXPORT_SYMBOL(kstrtouint); 230 231 /** 232 * kstrtoint - convert a string to an int 233 * @s: The start of the string. The string must be null-terminated, and may also 234 * include a single newline before its terminating null. The first character 235 * may also be a plus sign or a minus sign. 236 * @base: The number base to use. The maximum supported base is 16. If base is 237 * given as 0, then the base of the string is automatically detected with the 238 * conventional semantics - If it begins with 0x the number will be parsed as a 239 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be 240 * parsed as an octal number. Otherwise it will be parsed as a decimal. 241 * @res: Where to write the result of the conversion on success. 242 * 243 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error. 244 * Used as a replacement for the obsolete simple_strtoull. Return code must 245 * be checked. 246 */ 247 int kstrtoint(const char *s, unsigned int base, int *res) 248 { 249 long long tmp; 250 int rv; 251 252 rv = kstrtoll(s, base, &tmp); 253 if (rv < 0) 254 return rv; 255 if (tmp != (long long)(int)tmp) 256 return -ERANGE; 257 *res = tmp; 258 return 0; 259 } 260 EXPORT_SYMBOL(kstrtoint); 261 262 int kstrtou16(const char *s, unsigned int base, u16 *res) 263 { 264 unsigned long long tmp; 265 int rv; 266 267 rv = kstrtoull(s, base, &tmp); 268 if (rv < 0) 269 return rv; 270 if (tmp != (unsigned long long)(u16)tmp) 271 return -ERANGE; 272 *res = tmp; 273 return 0; 274 } 275 EXPORT_SYMBOL(kstrtou16); 276 277 int kstrtos16(const char *s, unsigned int base, s16 *res) 278 { 279 long long tmp; 280 int rv; 281 282 rv = kstrtoll(s, base, &tmp); 283 if (rv < 0) 284 return rv; 285 if (tmp != (long long)(s16)tmp) 286 return -ERANGE; 287 *res = tmp; 288 return 0; 289 } 290 EXPORT_SYMBOL(kstrtos16); 291 292 int kstrtou8(const char *s, unsigned int base, u8 *res) 293 { 294 unsigned long long tmp; 295 int rv; 296 297 rv = kstrtoull(s, base, &tmp); 298 if (rv < 0) 299 return rv; 300 if (tmp != (unsigned long long)(u8)tmp) 301 return -ERANGE; 302 *res = tmp; 303 return 0; 304 } 305 EXPORT_SYMBOL(kstrtou8); 306 307 int kstrtos8(const char *s, unsigned int base, s8 *res) 308 { 309 long long tmp; 310 int rv; 311 312 rv = kstrtoll(s, base, &tmp); 313 if (rv < 0) 314 return rv; 315 if (tmp != (long long)(s8)tmp) 316 return -ERANGE; 317 *res = tmp; 318 return 0; 319 } 320 EXPORT_SYMBOL(kstrtos8); 321 322 /** 323 * kstrtobool - convert common user inputs into boolean values 324 * @s: input string 325 * @res: result 326 * 327 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or 328 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value 329 * pointed to by res is updated upon finding a match. 330 */ 331 int kstrtobool(const char *s, bool *res) 332 { 333 if (!s) 334 return -EINVAL; 335 336 switch (s[0]) { 337 case 'y': 338 case 'Y': 339 case '1': 340 *res = true; 341 return 0; 342 case 'n': 343 case 'N': 344 case '0': 345 *res = false; 346 return 0; 347 case 'o': 348 case 'O': 349 switch (s[1]) { 350 case 'n': 351 case 'N': 352 *res = true; 353 return 0; 354 case 'f': 355 case 'F': 356 *res = false; 357 return 0; 358 default: 359 break; 360 } 361 default: 362 break; 363 } 364 365 return -EINVAL; 366 } 367 EXPORT_SYMBOL(kstrtobool); 368 369 /* 370 * Since "base" would be a nonsense argument, this open-codes the 371 * _from_user helper instead of using the helper macro below. 372 */ 373 int kstrtobool_from_user(const char __user *s, size_t count, bool *res) 374 { 375 /* Longest string needed to differentiate, newline, terminator */ 376 char buf[4]; 377 378 count = min(count, sizeof(buf) - 1); 379 if (copy_from_user(buf, s, count)) 380 return -EFAULT; 381 buf[count] = '\0'; 382 return kstrtobool(buf, res); 383 } 384 EXPORT_SYMBOL(kstrtobool_from_user); 385 386 #define kstrto_from_user(f, g, type) \ 387 int f(const char __user *s, size_t count, unsigned int base, type *res) \ 388 { \ 389 /* sign, base 2 representation, newline, terminator */ \ 390 char buf[1 + sizeof(type) * 8 + 1 + 1]; \ 391 \ 392 count = min(count, sizeof(buf) - 1); \ 393 if (copy_from_user(buf, s, count)) \ 394 return -EFAULT; \ 395 buf[count] = '\0'; \ 396 return g(buf, base, res); \ 397 } \ 398 EXPORT_SYMBOL(f) 399 400 kstrto_from_user(kstrtoull_from_user, kstrtoull, unsigned long long); 401 kstrto_from_user(kstrtoll_from_user, kstrtoll, long long); 402 kstrto_from_user(kstrtoul_from_user, kstrtoul, unsigned long); 403 kstrto_from_user(kstrtol_from_user, kstrtol, long); 404 kstrto_from_user(kstrtouint_from_user, kstrtouint, unsigned int); 405 kstrto_from_user(kstrtoint_from_user, kstrtoint, int); 406 kstrto_from_user(kstrtou16_from_user, kstrtou16, u16); 407 kstrto_from_user(kstrtos16_from_user, kstrtos16, s16); 408 kstrto_from_user(kstrtou8_from_user, kstrtou8, u8); 409 kstrto_from_user(kstrtos8_from_user, kstrtos8, s8); 410