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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); |