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