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/kstrtox.h> |
10 | #include <linux/parser.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/string.h> |
13 | |
14 | /* |
15 | * max size needed by different bases to express U64 |
16 | * HEX: "0xFFFFFFFFFFFFFFFF" --> 18 |
17 | * DEC: "18446744073709551615" --> 20 |
18 | * OCT: "01777777777777777777777" --> 23 |
19 | * pick the max one to define NUMBER_BUF_LEN |
20 | */ |
21 | #define NUMBER_BUF_LEN 24 |
22 | |
23 | /** |
24 | * match_one - Determines if a string matches a simple pattern |
25 | * @s: the string to examine for presence of the pattern |
26 | * @p: the string containing the pattern |
27 | * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match |
28 | * locations. |
29 | * |
30 | * Description: Determines if the pattern @p is present in string @s. Can only |
31 | * match extremely simple token=arg style patterns. If the pattern is found, |
32 | * the location(s) of the arguments will be returned in the @args array. |
33 | */ |
34 | static int match_one(char *s, const char *p, substring_t args[]) |
35 | { |
36 | char *meta; |
37 | int argc = 0; |
38 | |
39 | if (!p) |
40 | return 1; |
41 | |
42 | while(1) { |
43 | int len = -1; |
44 | meta = strchr(p, '%'); |
45 | if (!meta) |
46 | return strcmp(p, s) == 0; |
47 | |
48 | if (strncmp(p, s, meta-p)) |
49 | return 0; |
50 | |
51 | s += meta - p; |
52 | p = meta + 1; |
53 | |
54 | if (isdigit(c: *p)) |
55 | len = simple_strtoul(p, (char **) &p, 10); |
56 | else if (*p == '%') { |
57 | if (*s++ != '%') |
58 | return 0; |
59 | p++; |
60 | continue; |
61 | } |
62 | |
63 | if (argc >= MAX_OPT_ARGS) |
64 | return 0; |
65 | |
66 | args[argc].from = s; |
67 | switch (*p++) { |
68 | case 's': { |
69 | size_t str_len = strlen(s); |
70 | |
71 | if (str_len == 0) |
72 | return 0; |
73 | if (len == -1 || len > str_len) |
74 | len = str_len; |
75 | args[argc].to = s + len; |
76 | break; |
77 | } |
78 | case 'd': |
79 | simple_strtol(s, &args[argc].to, 0); |
80 | goto num; |
81 | case 'u': |
82 | simple_strtoul(s, &args[argc].to, 0); |
83 | goto num; |
84 | case 'o': |
85 | simple_strtoul(s, &args[argc].to, 8); |
86 | goto num; |
87 | case 'x': |
88 | simple_strtoul(s, &args[argc].to, 16); |
89 | num: |
90 | if (args[argc].to == args[argc].from) |
91 | return 0; |
92 | break; |
93 | default: |
94 | return 0; |
95 | } |
96 | s = args[argc].to; |
97 | argc++; |
98 | } |
99 | } |
100 | |
101 | /** |
102 | * match_token - Find a token (and optional args) in a string |
103 | * @s: the string to examine for token/argument pairs |
104 | * @table: match_table_t describing the set of allowed option tokens and the |
105 | * arguments that may be associated with them. Must be terminated with a |
106 | * &struct match_token whose pattern is set to the NULL pointer. |
107 | * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match |
108 | * locations. |
109 | * |
110 | * Description: Detects which if any of a set of token strings has been passed |
111 | * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style |
112 | * format identifiers which will be taken into account when matching the |
113 | * tokens, and whose locations will be returned in the @args array. |
114 | */ |
115 | int match_token(char *s, const match_table_t table, substring_t args[]) |
116 | { |
117 | const struct match_token *p; |
118 | |
119 | for (p = table; !match_one(s, p: p->pattern, args) ; p++) |
120 | ; |
121 | |
122 | return p->token; |
123 | } |
124 | EXPORT_SYMBOL(match_token); |
125 | |
126 | /** |
127 | * match_number - scan a number in the given base from a substring_t |
128 | * @s: substring to be scanned |
129 | * @result: resulting integer on success |
130 | * @base: base to use when converting string |
131 | * |
132 | * Description: Given a &substring_t and a base, attempts to parse the substring |
133 | * as a number in that base. |
134 | * |
135 | * Return: On success, sets @result to the integer represented by the |
136 | * string and returns 0. Returns -EINVAL or -ERANGE on failure. |
137 | */ |
138 | static int match_number(substring_t *s, int *result, int base) |
139 | { |
140 | char *endp; |
141 | char buf[NUMBER_BUF_LEN]; |
142 | int ret; |
143 | long val; |
144 | |
145 | if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) |
146 | return -ERANGE; |
147 | ret = 0; |
148 | val = simple_strtol(buf, &endp, base); |
149 | if (endp == buf) |
150 | ret = -EINVAL; |
151 | else if (val < (long)INT_MIN || val > (long)INT_MAX) |
152 | ret = -ERANGE; |
153 | else |
154 | *result = (int) val; |
155 | return ret; |
156 | } |
157 | |
158 | /** |
159 | * match_u64int - scan a number in the given base from a substring_t |
160 | * @s: substring to be scanned |
161 | * @result: resulting u64 on success |
162 | * @base: base to use when converting string |
163 | * |
164 | * Description: Given a &substring_t and a base, attempts to parse the substring |
165 | * as a number in that base. |
166 | * |
167 | * Return: On success, sets @result to the integer represented by the |
168 | * string and returns 0. Returns -EINVAL or -ERANGE on failure. |
169 | */ |
170 | static int match_u64int(substring_t *s, u64 *result, int base) |
171 | { |
172 | char buf[NUMBER_BUF_LEN]; |
173 | int ret; |
174 | u64 val; |
175 | |
176 | if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) |
177 | return -ERANGE; |
178 | ret = kstrtoull(s: buf, base, res: &val); |
179 | if (!ret) |
180 | *result = val; |
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. |
190 | * |
191 | * Return: On success, sets @result to the integer represented by the string |
192 | * and returns 0. Returns -EINVAL or -ERANGE on failure. |
193 | */ |
194 | int match_int(substring_t *s, int *result) |
195 | { |
196 | return match_number(s, result, base: 0); |
197 | } |
198 | EXPORT_SYMBOL(match_int); |
199 | |
200 | /** |
201 | * match_uint - scan a decimal representation of an integer from a substring_t |
202 | * @s: substring_t to be scanned |
203 | * @result: resulting integer on success |
204 | * |
205 | * Description: Attempts to parse the &substring_t @s as a decimal integer. |
206 | * |
207 | * Return: On success, sets @result to the integer represented by the string |
208 | * and returns 0. Returns -EINVAL or -ERANGE on failure. |
209 | */ |
210 | int match_uint(substring_t *s, unsigned int *result) |
211 | { |
212 | char buf[NUMBER_BUF_LEN]; |
213 | |
214 | if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) |
215 | return -ERANGE; |
216 | |
217 | return kstrtouint(s: buf, base: 10, res: result); |
218 | } |
219 | EXPORT_SYMBOL(match_uint); |
220 | |
221 | /** |
222 | * match_u64 - scan a decimal representation of a u64 from |
223 | * a substring_t |
224 | * @s: substring_t to be scanned |
225 | * @result: resulting unsigned long long on success |
226 | * |
227 | * Description: Attempts to parse the &substring_t @s as a long decimal |
228 | * integer. |
229 | * |
230 | * Return: On success, sets @result to the integer represented by the string |
231 | * and returns 0. Returns -EINVAL or -ERANGE on failure. |
232 | */ |
233 | int match_u64(substring_t *s, u64 *result) |
234 | { |
235 | return match_u64int(s, result, base: 0); |
236 | } |
237 | EXPORT_SYMBOL(match_u64); |
238 | |
239 | /** |
240 | * match_octal - scan an octal representation of an integer from a substring_t |
241 | * @s: substring_t to be scanned |
242 | * @result: resulting integer on success |
243 | * |
244 | * Description: Attempts to parse the &substring_t @s as an octal integer. |
245 | * |
246 | * Return: On success, sets @result to the integer represented by the string |
247 | * and returns 0. Returns -EINVAL or -ERANGE on failure. |
248 | */ |
249 | int match_octal(substring_t *s, int *result) |
250 | { |
251 | return match_number(s, result, base: 8); |
252 | } |
253 | EXPORT_SYMBOL(match_octal); |
254 | |
255 | /** |
256 | * match_hex - scan a hex representation of an integer from a substring_t |
257 | * @s: substring_t to be scanned |
258 | * @result: resulting integer on success |
259 | * |
260 | * Description: Attempts to parse the &substring_t @s as a hexadecimal integer. |
261 | * |
262 | * Return: On success, sets @result to the integer represented by the string |
263 | * and returns 0. Returns -EINVAL or -ERANGE on failure. |
264 | */ |
265 | int match_hex(substring_t *s, int *result) |
266 | { |
267 | return match_number(s, result, base: 16); |
268 | } |
269 | EXPORT_SYMBOL(match_hex); |
270 | |
271 | /** |
272 | * match_wildcard - parse if a string matches given wildcard pattern |
273 | * @pattern: wildcard pattern |
274 | * @str: the string to be parsed |
275 | * |
276 | * Description: Parse the string @str to check if matches wildcard |
277 | * pattern @pattern. The pattern may contain two types of wildcards: |
278 | * '*' - matches zero or more characters |
279 | * '?' - matches one character |
280 | * |
281 | * Return: If the @str matches the @pattern, return true, else return false. |
282 | */ |
283 | bool match_wildcard(const char *pattern, const char *str) |
284 | { |
285 | const char *s = str; |
286 | const char *p = pattern; |
287 | bool star = false; |
288 | |
289 | while (*s) { |
290 | switch (*p) { |
291 | case '?': |
292 | s++; |
293 | p++; |
294 | break; |
295 | case '*': |
296 | star = true; |
297 | str = s; |
298 | if (!*++p) |
299 | return true; |
300 | pattern = p; |
301 | break; |
302 | default: |
303 | if (*s == *p) { |
304 | s++; |
305 | p++; |
306 | } else { |
307 | if (!star) |
308 | return false; |
309 | str++; |
310 | s = str; |
311 | p = pattern; |
312 | } |
313 | break; |
314 | } |
315 | } |
316 | |
317 | if (*p == '*') |
318 | ++p; |
319 | return !*p; |
320 | } |
321 | EXPORT_SYMBOL(match_wildcard); |
322 | |
323 | /** |
324 | * match_strlcpy - Copy the characters from a substring_t to a sized buffer |
325 | * @dest: where to copy to |
326 | * @src: &substring_t to copy |
327 | * @size: size of destination buffer |
328 | * |
329 | * Description: Copy the characters in &substring_t @src to the |
330 | * c-style string @dest. Copy no more than @size - 1 characters, plus |
331 | * the terminating NUL. |
332 | * |
333 | * Return: length of @src. |
334 | */ |
335 | size_t match_strlcpy(char *dest, const substring_t *src, size_t size) |
336 | { |
337 | size_t ret = src->to - src->from; |
338 | |
339 | if (size) { |
340 | size_t len = ret >= size ? size - 1 : ret; |
341 | memcpy(dest, src->from, len); |
342 | dest[len] = '\0'; |
343 | } |
344 | return ret; |
345 | } |
346 | EXPORT_SYMBOL(match_strlcpy); |
347 | |
348 | /** |
349 | * match_strdup - allocate a new string with the contents of a substring_t |
350 | * @s: &substring_t to copy |
351 | * |
352 | * Description: Allocates and returns a string filled with the contents of |
353 | * the &substring_t @s. The caller is responsible for freeing the returned |
354 | * string with kfree(). |
355 | * |
356 | * Return: the address of the newly allocated NUL-terminated string or |
357 | * %NULL on error. |
358 | */ |
359 | char *match_strdup(const substring_t *s) |
360 | { |
361 | return kmemdup_nul(s: s->from, len: s->to - s->from, GFP_KERNEL); |
362 | } |
363 | EXPORT_SYMBOL(match_strdup); |
364 | |