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