1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * lib/parser.c - simple parser for mount, etc. options. 4 */ 5 6 #include <linux/ctype.h> 7 #include <linux/types.h> 8 #include <linux/export.h> 9 #include <linux/kstrtox.h> 10 #include <linux/parser.h> 11 #include <linux/slab.h> 12 #include <linux/string.h> 13 14 /* 15 * max size needed by different bases to express U64 16 * HEX: "0xFFFFFFFFFFFFFFFF" --> 18 17 * DEC: "18446744073709551615" --> 20 18 * OCT: "01777777777777777777777" --> 23 19 * pick the max one to define NUMBER_BUF_LEN 20 */ 21 #define NUMBER_BUF_LEN 24 22 23 /** 24 * match_one - Determines if a string matches a simple pattern 25 * @s: the string to examine for presence of the pattern 26 * @p: the string containing the pattern 27 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match 28 * locations. 29 * 30 * Description: Determines if the pattern @p is present in string @s. Can only 31 * match extremely simple token=arg style patterns. If the pattern is found, 32 * the location(s) of the arguments will be returned in the @args array. 33 */ 34 static int match_one(char *s, const char *p, substring_t args[]) 35 { 36 char *meta; 37 int argc = 0; 38 39 if (!p) 40 return 1; 41 42 while(1) { 43 int len = -1; 44 meta = strchr(p, '%'); 45 if (!meta) 46 return strcmp(p, s) == 0; 47 48 if (strncmp(p, s, meta-p)) 49 return 0; 50 51 s += meta - p; 52 p = meta + 1; 53 54 if (isdigit(*p)) 55 len = simple_strtoul(p, (char **) &p, 10); 56 else if (*p == '%') { 57 if (*s++ != '%') 58 return 0; 59 p++; 60 continue; 61 } 62 63 if (argc >= MAX_OPT_ARGS) 64 return 0; 65 66 args[argc].from = s; 67 switch (*p++) { 68 case 's': { 69 size_t str_len = strlen(s); 70 71 if (str_len == 0) 72 return 0; 73 if (len == -1 || len > str_len) 74 len = str_len; 75 args[argc].to = s + len; 76 break; 77 } 78 case 'd': 79 simple_strtol(s, &args[argc].to, 0); 80 goto num; 81 case 'u': 82 simple_strtoul(s, &args[argc].to, 0); 83 goto num; 84 case 'o': 85 simple_strtoul(s, &args[argc].to, 8); 86 goto num; 87 case 'x': 88 simple_strtoul(s, &args[argc].to, 16); 89 num: 90 if (args[argc].to == args[argc].from) 91 return 0; 92 break; 93 default: 94 return 0; 95 } 96 s = args[argc].to; 97 argc++; 98 } 99 } 100 101 /** 102 * match_token - Find a token (and optional args) in a string 103 * @s: the string to examine for token/argument pairs 104 * @table: match_table_t describing the set of allowed option tokens and the 105 * arguments that may be associated with them. Must be terminated with a 106 * &struct match_token whose pattern is set to the NULL pointer. 107 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match 108 * locations. 109 * 110 * Description: Detects which if any of a set of token strings has been passed 111 * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style 112 * format identifiers which will be taken into account when matching the 113 * tokens, and whose locations will be returned in the @args array. 114 */ 115 int match_token(char *s, const match_table_t table, substring_t args[]) 116 { 117 const struct match_token *p; 118 119 for (p = table; !match_one(s, p->pattern, args) ; p++) 120 ; 121 122 return p->token; 123 } 124 EXPORT_SYMBOL(match_token); 125 126 /** 127 * match_number - scan a number in the given base from a substring_t 128 * @s: substring to be scanned 129 * @result: resulting integer on success 130 * @base: base to use when converting string 131 * 132 * Description: Given a &substring_t and a base, attempts to parse the substring 133 * as a number in that base. 134 * 135 * Return: On success, sets @result to the integer represented by the 136 * string and returns 0. Returns -EINVAL or -ERANGE on failure. 137 */ 138 static int match_number(substring_t *s, int *result, int base) 139 { 140 char *endp; 141 char buf[NUMBER_BUF_LEN]; 142 int ret; 143 long val; 144 145 if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) 146 return -ERANGE; 147 ret = 0; 148 val = simple_strtol(buf, &endp, base); 149 if (endp == buf) 150 ret = -EINVAL; 151 else if (val < (long)INT_MIN || val > (long)INT_MAX) 152 ret = -ERANGE; 153 else 154 *result = (int) val; 155 return ret; 156 } 157 158 /** 159 * match_u64int - scan a number in the given base from a substring_t 160 * @s: substring to be scanned 161 * @result: resulting u64 on success 162 * @base: base to use when converting string 163 * 164 * Description: Given a &substring_t and a base, attempts to parse the substring 165 * as a number in that base. 166 * 167 * Return: On success, sets @result to the integer represented by the 168 * string and returns 0. Returns -EINVAL or -ERANGE on failure. 169 */ 170 static int match_u64int(substring_t *s, u64 *result, int base) 171 { 172 char buf[NUMBER_BUF_LEN]; 173 int ret; 174 u64 val; 175 176 if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) 177 return -ERANGE; 178 ret = kstrtoull(buf, base, &val); 179 if (!ret) 180 *result = val; 181 return ret; 182 } 183 184 /** 185 * match_int - scan a decimal representation of an integer from a substring_t 186 * @s: substring_t to be scanned 187 * @result: resulting integer on success 188 * 189 * Description: Attempts to parse the &substring_t @s as a decimal integer. 190 * 191 * Return: On success, sets @result to the integer represented by the string 192 * and returns 0. Returns -EINVAL or -ERANGE on failure. 193 */ 194 int match_int(substring_t *s, int *result) 195 { 196 return match_number(s, result, 0); 197 } 198 EXPORT_SYMBOL(match_int); 199 200 /** 201 * match_uint - scan a decimal representation of an integer from a substring_t 202 * @s: substring_t to be scanned 203 * @result: resulting integer on success 204 * 205 * Description: Attempts to parse the &substring_t @s as a decimal integer. 206 * 207 * Return: On success, sets @result to the integer represented by the string 208 * and returns 0. Returns -EINVAL or -ERANGE on failure. 209 */ 210 int match_uint(substring_t *s, unsigned int *result) 211 { 212 char buf[NUMBER_BUF_LEN]; 213 214 if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) 215 return -ERANGE; 216 217 return kstrtouint(buf, 10, result); 218 } 219 EXPORT_SYMBOL(match_uint); 220 221 /** 222 * match_u64 - scan a decimal representation of a u64 from 223 * a substring_t 224 * @s: substring_t to be scanned 225 * @result: resulting unsigned long long on success 226 * 227 * Description: Attempts to parse the &substring_t @s as a long decimal 228 * integer. 229 * 230 * Return: On success, sets @result to the integer represented by the string 231 * and returns 0. Returns -EINVAL or -ERANGE on failure. 232 */ 233 int match_u64(substring_t *s, u64 *result) 234 { 235 return match_u64int(s, result, 0); 236 } 237 EXPORT_SYMBOL(match_u64); 238 239 /** 240 * match_octal - scan an octal representation of an integer from a substring_t 241 * @s: substring_t to be scanned 242 * @result: resulting integer on success 243 * 244 * Description: Attempts to parse the &substring_t @s as an octal integer. 245 * 246 * Return: On success, sets @result to the integer represented by the string 247 * and returns 0. Returns -EINVAL or -ERANGE on failure. 248 */ 249 int match_octal(substring_t *s, int *result) 250 { 251 return match_number(s, result, 8); 252 } 253 EXPORT_SYMBOL(match_octal); 254 255 /** 256 * match_hex - scan a hex representation of an integer from a substring_t 257 * @s: substring_t to be scanned 258 * @result: resulting integer on success 259 * 260 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer. 261 * 262 * Return: On success, sets @result to the integer represented by the string 263 * and returns 0. Returns -EINVAL or -ERANGE on failure. 264 */ 265 int match_hex(substring_t *s, int *result) 266 { 267 return match_number(s, result, 16); 268 } 269 EXPORT_SYMBOL(match_hex); 270 271 /** 272 * match_wildcard - parse if a string matches given wildcard pattern 273 * @pattern: wildcard pattern 274 * @str: the string to be parsed 275 * 276 * Description: Parse the string @str to check if matches wildcard 277 * pattern @pattern. The pattern may contain two types of wildcards: 278 * '*' - matches zero or more characters 279 * '?' - matches one character 280 * 281 * Return: If the @str matches the @pattern, return true, else return false. 282 */ 283 bool match_wildcard(const char *pattern, const char *str) 284 { 285 const char *s = str; 286 const char *p = pattern; 287 bool star = false; 288 289 while (*s) { 290 switch (*p) { 291 case '?': 292 s++; 293 p++; 294 break; 295 case '*': 296 star = true; 297 str = s; 298 if (!*++p) 299 return true; 300 pattern = p; 301 break; 302 default: 303 if (*s == *p) { 304 s++; 305 p++; 306 } else { 307 if (!star) 308 return false; 309 str++; 310 s = str; 311 p = pattern; 312 } 313 break; 314 } 315 } 316 317 if (*p == '*') 318 ++p; 319 return !*p; 320 } 321 EXPORT_SYMBOL(match_wildcard); 322 323 /** 324 * match_strlcpy - Copy the characters from a substring_t to a sized buffer 325 * @dest: where to copy to 326 * @src: &substring_t to copy 327 * @size: size of destination buffer 328 * 329 * Description: Copy the characters in &substring_t @src to the 330 * c-style string @dest. Copy no more than @size - 1 characters, plus 331 * the terminating NUL. 332 * 333 * Return: length of @src. 334 */ 335 size_t match_strlcpy(char *dest, const substring_t *src, size_t size) 336 { 337 size_t ret = src->to - src->from; 338 339 if (size) { 340 size_t len = ret >= size ? size - 1 : ret; 341 memcpy(dest, src->from, len); 342 dest[len] = '\0'; 343 } 344 return ret; 345 } 346 EXPORT_SYMBOL(match_strlcpy); 347 348 /** 349 * match_strdup - allocate a new string with the contents of a substring_t 350 * @s: &substring_t to copy 351 * 352 * Description: Allocates and returns a string filled with the contents of 353 * the &substring_t @s. The caller is responsible for freeing the returned 354 * string with kfree(). 355 * 356 * Return: the address of the newly allocated NUL-terminated string or 357 * %NULL on error. 358 */ 359 char *match_strdup(const substring_t *s) 360 { 361 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL); 362 } 363 EXPORT_SYMBOL(match_strdup); 364