projects/linux·blob v5.13-rc3 · refs

361 lines · 8.8 KiB

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/parser.h>
10#include <linux/slab.h>
11#include <linux/string.h>
12
13/**
14 * match_one - Determines if a string matches a simple pattern
15 * @s: the string to examine for presence of the pattern
16 * @p: the string containing the pattern
17 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
18 * locations.
19 *
20 * Description: Determines if the pattern @p is present in string @s. Can only
21 * match extremely simple token=arg style patterns. If the pattern is found,
22 * the location(s) of the arguments will be returned in the @args array.
23 */
24static int match_one(char *s, const char *p, substring_t args[])
25{
26 char *meta;
27 int argc = 0;
28
29 if (!p)
30 return 1;
31
32 while(1) {
33 int len = -1;
34 meta = strchr(p, '%');
35 if (!meta)
36 return strcmp(p, s) == 0;
37
38 if (strncmp(p, s, meta-p))
39 return 0;
40
41 s += meta - p;
42 p = meta + 1;
43
44 if (isdigit(*p))
45 len = simple_strtoul(p, (char **) &p, 10);
46 else if (*p == '%') {
47 if (*s++ != '%')
48 return 0;
49 p++;
50 continue;
51 }
52
53 if (argc >= MAX_OPT_ARGS)
54 return 0;
55
56 args[argc].from = s;
57 switch (*p++) {
58 case 's': {
59 size_t str_len = strlen(s);
60
61 if (str_len == 0)
62 return 0;
63 if (len == -1 || len > str_len)
64 len = str_len;
65 args[argc].to = s + len;
66 break;
67 }
68 case 'd':
69 simple_strtol(s, &args[argc].to, 0);
70 goto num;
71 case 'u':
72 simple_strtoul(s, &args[argc].to, 0);
73 goto num;
74 case 'o':
75 simple_strtoul(s, &args[argc].to, 8);
76 goto num;
77 case 'x':
78 simple_strtoul(s, &args[argc].to, 16);
79 num:
80 if (args[argc].to == args[argc].from)
81 return 0;
82 break;
83 default:
84 return 0;
85 }
86 s = args[argc].to;
87 argc++;
88 }
89}
90
91/**
92 * match_token - Find a token (and optional args) in a string
93 * @s: the string to examine for token/argument pairs
94 * @table: match_table_t describing the set of allowed option tokens and the
95 * arguments that may be associated with them. Must be terminated with a
96 * &struct match_token whose pattern is set to the NULL pointer.
97 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
98 * locations.
99 *
100 * Description: Detects which if any of a set of token strings has been passed
101 * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style
102 * format identifiers which will be taken into account when matching the
103 * tokens, and whose locations will be returned in the @args array.
104 */
105int match_token(char *s, const match_table_t table, substring_t args[])
106{
107 const struct match_token *p;
108
109 for (p = table; !match_one(s, p->pattern, args) ; p++)
110 ;
111
112 return p->token;
113}
114EXPORT_SYMBOL(match_token);
115
116/**
117 * match_number - scan a number in the given base from a substring_t
118 * @s: substring to be scanned
119 * @result: resulting integer on success
120 * @base: base to use when converting string
121 *
122 * Description: Given a &substring_t and a base, attempts to parse the substring
123 * as a number in that base.
124 *
125 * Return: On success, sets @result to the integer represented by the
126 * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
127 */
128static 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.
159 *
160 * Return: On success, sets @result to the integer represented by the
161 * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
162 */
163static int match_u64int(substring_t *s, u64 *result, int base)
164{
165 char *buf;
166 int ret;
167 u64 val;
168
169 buf = match_strdup(s);
170 if (!buf)
171 return -ENOMEM;
172
173 ret = kstrtoull(buf, base, &val);
174 if (!ret)
175 *result = val;
176 kfree(buf);
177 return ret;
178}
179
180/**
181 * match_int - scan a decimal representation of an integer from a substring_t
182 * @s: substring_t to be scanned
183 * @result: resulting integer on success
184 *
185 * Description: Attempts to parse the &substring_t @s as a decimal integer.
186 *
187 * Return: On success, sets @result to the integer represented by the string
188 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
189 */
190int match_int(substring_t *s, int *result)
191{
192 return match_number(s, result, 0);
193}
194EXPORT_SYMBOL(match_int);
195
196/**
197 * match_uint - scan a decimal representation of an integer from a substring_t
198 * @s: substring_t to be scanned
199 * @result: resulting integer on success
200 *
201 * Description: Attempts to parse the &substring_t @s as a decimal integer.
202 *
203 * Return: On success, sets @result to the integer represented by the string
204 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
205 */
206int match_uint(substring_t *s, unsigned int *result)
207{
208 int err = -ENOMEM;
209 char *buf = match_strdup(s);
210
211 if (buf) {
212 err = kstrtouint(buf, 10, result);
213 kfree(buf);
214 }
215 return err;
216}
217EXPORT_SYMBOL(match_uint);
218
219/**
220 * match_u64 - scan a decimal representation of a u64 from
221 * a substring_t
222 * @s: substring_t to be scanned
223 * @result: resulting unsigned long long on success
224 *
225 * Description: Attempts to parse the &substring_t @s as a long decimal
226 * integer.
227 *
228 * Return: On success, sets @result to the integer represented by the string
229 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
230 */
231int match_u64(substring_t *s, u64 *result)
232{
233 return match_u64int(s, result, 0);
234}
235EXPORT_SYMBOL(match_u64);
236
237/**
238 * match_octal - scan an octal representation of an integer from a substring_t
239 * @s: substring_t to be scanned
240 * @result: resulting integer on success
241 *
242 * Description: Attempts to parse the &substring_t @s as an octal integer.
243 *
244 * Return: On success, sets @result to the integer represented by the string
245 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
246 */
247int match_octal(substring_t *s, int *result)
248{
249 return match_number(s, result, 8);
250}
251EXPORT_SYMBOL(match_octal);
252
253/**
254 * match_hex - scan a hex representation of an integer from a substring_t
255 * @s: substring_t to be scanned
256 * @result: resulting integer on success
257 *
258 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
259 *
260 * Return: On success, sets @result to the integer represented by the string
261 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
262 */
263int match_hex(substring_t *s, int *result)
264{
265 return match_number(s, result, 16);
266}
267EXPORT_SYMBOL(match_hex);
268
269/**
270 * match_wildcard - parse if a string matches given wildcard pattern
271 * @pattern: wildcard pattern
272 * @str: the string to be parsed
273 *
274 * Description: Parse the string @str to check if matches wildcard
275 * pattern @pattern. The pattern may contain two types of wildcards:
276 * '*' - matches zero or more characters
277 * '?' - matches one character
278 *
279 * Return: If the @str matches the @pattern, return true, else return false.
280 */
281bool match_wildcard(const char *pattern, const char *str)
282{
283 const char *s = str;
284 const char *p = pattern;
285 bool star = false;
286
287 while (*s) {
288 switch (*p) {
289 case '?':
290 s++;
291 p++;
292 break;
293 case '*':
294 star = true;
295 str = s;
296 if (!*++p)
297 return true;
298 pattern = p;
299 break;
300 default:
301 if (*s == *p) {
302 s++;
303 p++;
304 } else {
305 if (!star)
306 return false;
307 str++;
308 s = str;
309 p = pattern;
310 }
311 break;
312 }
313 }
314
315 if (*p == '*')
316 ++p;
317 return !*p;
318}
319EXPORT_SYMBOL(match_wildcard);
320
321/**
322 * match_strlcpy - Copy the characters from a substring_t to a sized buffer
323 * @dest: where to copy to
324 * @src: &substring_t to copy
325 * @size: size of destination buffer
326 *
327 * Description: Copy the characters in &substring_t @src to the
328 * c-style string @dest. Copy no more than @size - 1 characters, plus
329 * the terminating NUL.
330 *
331 * Return: length of @src.
332 */
333size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
334{
335 size_t ret = src->to - src->from;
336
337 if (size) {
338 size_t len = ret >= size ? size - 1 : ret;
339 memcpy(dest, src->from, len);
340 dest[len] = '\0';
341 }
342 return ret;
343}
344EXPORT_SYMBOL(match_strlcpy);
345
346/**
347 * match_strdup - allocate a new string with the contents of a substring_t
348 * @s: &substring_t to copy
349 *
350 * Description: Allocates and returns a string filled with the contents of
351 * the &substring_t @s. The caller is responsible for freeing the returned
352 * string with kfree().
353 *
354 * Return: the address of the newly allocated NUL-terminated string or
355 * %NULL on error.
356 */
357char *match_strdup(const substring_t *s)
358{
359 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
360}
361EXPORT_SYMBOL(match_strdup);