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; 134 135 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. On success, sets @result to the integer represented 159 * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. 160 */ 161 static int match_u64int(substring_t *s, u64 *result, int base) 162 { 163 char *buf; 164 int ret; 165 u64 val; 166 167 buf = match_strdup(s); 168 if (!buf) 169 return -ENOMEM; 170 171 ret = kstrtoull(buf, base, &val); 172 if (!ret) 173 *result = val; 174 kfree(buf); 175 return ret; 176 } 177 178 /** 179 * match_int: - scan a decimal representation of an integer from a substring_t 180 * @s: substring_t to be scanned 181 * @result: resulting integer on success 182 * 183 * Description: Attempts to parse the &substring_t @s as a decimal integer. On 184 * success, sets @result to the integer represented by the string and returns 0. 185 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure. 186 */ 187 int match_int(substring_t *s, int *result) 188 { 189 return match_number(s, result, 0); 190 } 191 EXPORT_SYMBOL(match_int); 192 193 /** 194 * match_u64: - scan a decimal representation of a u64 from 195 * a substring_t 196 * @s: substring_t to be scanned 197 * @result: resulting unsigned long long on success 198 * 199 * Description: Attempts to parse the &substring_t @s as a long decimal 200 * integer. On success, sets @result to the integer represented by the 201 * string and returns 0. 202 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure. 203 */ 204 int match_u64(substring_t *s, u64 *result) 205 { 206 return match_u64int(s, result, 0); 207 } 208 EXPORT_SYMBOL(match_u64); 209 210 /** 211 * match_octal: - scan an octal representation of an integer from a substring_t 212 * @s: substring_t to be scanned 213 * @result: resulting integer on success 214 * 215 * Description: Attempts to parse the &substring_t @s as an octal integer. On 216 * success, sets @result to the integer represented by the string and returns 217 * 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. 218 */ 219 int match_octal(substring_t *s, int *result) 220 { 221 return match_number(s, result, 8); 222 } 223 EXPORT_SYMBOL(match_octal); 224 225 /** 226 * match_hex: - scan a hex representation of an integer from a substring_t 227 * @s: substring_t to be scanned 228 * @result: resulting integer on success 229 * 230 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer. 231 * On success, sets @result to the integer represented by the string and 232 * returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. 233 */ 234 int match_hex(substring_t *s, int *result) 235 { 236 return match_number(s, result, 16); 237 } 238 EXPORT_SYMBOL(match_hex); 239 240 /** 241 * match_wildcard: - parse if a string matches given wildcard pattern 242 * @pattern: wildcard pattern 243 * @str: the string to be parsed 244 * 245 * Description: Parse the string @str to check if matches wildcard 246 * pattern @pattern. The pattern may contain two type wildcardes: 247 * '*' - matches zero or more characters 248 * '?' - matches one character 249 * If it's matched, return true, else return false. 250 */ 251 bool match_wildcard(const char *pattern, const char *str) 252 { 253 const char *s = str; 254 const char *p = pattern; 255 bool star = false; 256 257 while (*s) { 258 switch (*p) { 259 case '?': 260 s++; 261 p++; 262 break; 263 case '*': 264 star = true; 265 str = s; 266 if (!*++p) 267 return true; 268 pattern = p; 269 break; 270 default: 271 if (*s == *p) { 272 s++; 273 p++; 274 } else { 275 if (!star) 276 return false; 277 str++; 278 s = str; 279 p = pattern; 280 } 281 break; 282 } 283 } 284 285 if (*p == '*') 286 ++p; 287 return !*p; 288 } 289 EXPORT_SYMBOL(match_wildcard); 290 291 /** 292 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer 293 * @dest: where to copy to 294 * @src: &substring_t to copy 295 * @size: size of destination buffer 296 * 297 * Description: Copy the characters in &substring_t @src to the 298 * c-style string @dest. Copy no more than @size - 1 characters, plus 299 * the terminating NUL. Return length of @src. 300 */ 301 size_t match_strlcpy(char *dest, const substring_t *src, size_t size) 302 { 303 size_t ret = src->to - src->from; 304 305 if (size) { 306 size_t len = ret >= size ? size - 1 : ret; 307 memcpy(dest, src->from, len); 308 dest[len] = '\0'; 309 } 310 return ret; 311 } 312 EXPORT_SYMBOL(match_strlcpy); 313 314 /** 315 * match_strdup: - allocate a new string with the contents of a substring_t 316 * @s: &substring_t to copy 317 * 318 * Description: Allocates and returns a string filled with the contents of 319 * the &substring_t @s. The caller is responsible for freeing the returned 320 * string with kfree(). 321 */ 322 char *match_strdup(const substring_t *s) 323 { 324 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL); 325 } 326 EXPORT_SYMBOL(match_strdup); 327