| 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_int: - scan a decimal representation of an integer from a substring_t |
| 156 | * @s: substring_t to be scanned |
| 157 | * @result: resulting integer on success |
| 158 | * |
| 159 | * Description: Attempts to parse the &substring_t @s as a decimal integer. On |
| 160 | * success, sets @result to the integer represented by the string and returns 0. |
| 161 | * Returns -ENOMEM, -EINVAL, or -ERANGE on failure. |
| 162 | */ |
| 163 | int match_int(substring_t *s, int *result) |
| 164 | { |
| 165 | return match_number(s, result, 0); |
| 166 | } |
| 167 | EXPORT_SYMBOL(match_int); |
| 168 | |
| 169 | /** |
| 170 | * match_octal: - scan an octal representation of an integer from a substring_t |
| 171 | * @s: substring_t to be scanned |
| 172 | * @result: resulting integer on success |
| 173 | * |
| 174 | * Description: Attempts to parse the &substring_t @s as an octal integer. On |
| 175 | * success, sets @result to the integer represented by the string and returns |
| 176 | * 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. |
| 177 | */ |
| 178 | int match_octal(substring_t *s, int *result) |
| 179 | { |
| 180 | return match_number(s, result, 8); |
| 181 | } |
| 182 | EXPORT_SYMBOL(match_octal); |
| 183 | |
| 184 | /** |
| 185 | * match_hex: - scan a hex 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 hexadecimal integer. |
| 190 | * On success, sets @result to the integer represented by the string and |
| 191 | * returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure. |
| 192 | */ |
| 193 | int match_hex(substring_t *s, int *result) |
| 194 | { |
| 195 | return match_number(s, result, 16); |
| 196 | } |
| 197 | EXPORT_SYMBOL(match_hex); |
| 198 | |
| 199 | /** |
| 200 | * match_wildcard: - parse if a string matches given wildcard pattern |
| 201 | * @pattern: wildcard pattern |
| 202 | * @str: the string to be parsed |
| 203 | * |
| 204 | * Description: Parse the string @str to check if matches wildcard |
| 205 | * pattern @pattern. The pattern may contain two type wildcardes: |
| 206 | * '*' - matches zero or more characters |
| 207 | * '?' - matches one character |
| 208 | * If it's matched, return true, else return false. |
| 209 | */ |
| 210 | bool match_wildcard(const char *pattern, const char *str) |
| 211 | { |
| 212 | const char *s = str; |
| 213 | const char *p = pattern; |
| 214 | bool star = false; |
| 215 | |
| 216 | while (*s) { |
| 217 | switch (*p) { |
| 218 | case '?': |
| 219 | s++; |
| 220 | p++; |
| 221 | break; |
| 222 | case '*': |
| 223 | star = true; |
| 224 | str = s; |
| 225 | if (!*++p) |
| 226 | return true; |
| 227 | pattern = p; |
| 228 | break; |
| 229 | default: |
| 230 | if (*s == *p) { |
| 231 | s++; |
| 232 | p++; |
| 233 | } else { |
| 234 | if (!star) |
| 235 | return false; |
| 236 | str++; |
| 237 | s = str; |
| 238 | p = pattern; |
| 239 | } |
| 240 | break; |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | if (*p == '*') |
| 245 | ++p; |
| 246 | return !*p; |
| 247 | } |
| 248 | EXPORT_SYMBOL(match_wildcard); |
| 249 | |
| 250 | /** |
| 251 | * match_strlcpy: - Copy the characters from a substring_t to a sized buffer |
| 252 | * @dest: where to copy to |
| 253 | * @src: &substring_t to copy |
| 254 | * @size: size of destination buffer |
| 255 | * |
| 256 | * Description: Copy the characters in &substring_t @src to the |
| 257 | * c-style string @dest. Copy no more than @size - 1 characters, plus |
| 258 | * the terminating NUL. Return length of @src. |
| 259 | */ |
| 260 | size_t match_strlcpy(char *dest, const substring_t *src, size_t size) |
| 261 | { |
| 262 | size_t ret = src->to - src->from; |
| 263 | |
| 264 | if (size) { |
| 265 | size_t len = ret >= size ? size - 1 : ret; |
| 266 | memcpy(dest, src->from, len); |
| 267 | dest[len] = '\0'; |
| 268 | } |
| 269 | return ret; |
| 270 | } |
| 271 | EXPORT_SYMBOL(match_strlcpy); |
| 272 | |
| 273 | /** |
| 274 | * match_strdup: - allocate a new string with the contents of a substring_t |
| 275 | * @s: &substring_t to copy |
| 276 | * |
| 277 | * Description: Allocates and returns a string filled with the contents of |
| 278 | * the &substring_t @s. The caller is responsible for freeing the returned |
| 279 | * string with kfree(). |
| 280 | */ |
| 281 | char *match_strdup(const substring_t *s) |
| 282 | { |
| 283 | size_t sz = s->to - s->from + 1; |
| 284 | char *p = kmalloc(sz, GFP_KERNEL); |
| 285 | if (p) |
| 286 | match_strlcpy(p, s, sz); |
| 287 | return p; |
| 288 | } |
| 289 | EXPORT_SYMBOL(match_strdup); |