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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 */
26static 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 */
107int 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}
116EXPORT_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 */
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 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 */
163int match_int(substring_t *s, int *result)
164{
165 return match_number(s, result, 0);
166}
167EXPORT_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 */
178int match_octal(substring_t *s, int *result)
179{
180 return match_number(s, result, 8);
181}
182EXPORT_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 */
193int match_hex(substring_t *s, int *result)
194{
195 return match_number(s, result, 16);
196}
197EXPORT_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 */
210bool 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}
248EXPORT_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 */
260size_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}
271EXPORT_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 */
281char *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}
289EXPORT_SYMBOL(match_strdup);
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 * match_one - Determines if a string matches a simple pattern
16 * @s: the string to examine for presence of the pattern
17 * @p: the string containing the pattern
18 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
19 * locations.
20 *
21 * Description: Determines if the pattern @p is present in string @s. Can only
22 * match extremely simple token=arg style patterns. If the pattern is found,
23 * the location(s) of the arguments will be returned in the @args array.
24 */
25static int match_one(char *s, const char *p, substring_t args[])
26{
27 char *meta;
28 int argc = 0;
29
30 if (!p)
31 return 1;
32
33 while(1) {
34 int len = -1;
35 meta = strchr(p, '%');
36 if (!meta)
37 return strcmp(p, s) == 0;
38
39 if (strncmp(p, s, meta-p))
40 return 0;
41
42 s += meta - p;
43 p = meta + 1;
44
45 if (isdigit(*p))
46 len = simple_strtoul(p, (char **) &p, 10);
47 else if (*p == '%') {
48 if (*s++ != '%')
49 return 0;
50 p++;
51 continue;
52 }
53
54 if (argc >= MAX_OPT_ARGS)
55 return 0;
56
57 args[argc].from = s;
58 switch (*p++) {
59 case 's': {
60 size_t str_len = strlen(s);
61
62 if (str_len == 0)
63 return 0;
64 if (len == -1 || len > str_len)
65 len = str_len;
66 args[argc].to = s + len;
67 break;
68 }
69 case 'd':
70 simple_strtol(s, &args[argc].to, 0);
71 goto num;
72 case 'u':
73 simple_strtoul(s, &args[argc].to, 0);
74 goto num;
75 case 'o':
76 simple_strtoul(s, &args[argc].to, 8);
77 goto num;
78 case 'x':
79 simple_strtoul(s, &args[argc].to, 16);
80 num:
81 if (args[argc].to == args[argc].from)
82 return 0;
83 break;
84 default:
85 return 0;
86 }
87 s = args[argc].to;
88 argc++;
89 }
90}
91
92/**
93 * match_token - Find a token (and optional args) in a string
94 * @s: the string to examine for token/argument pairs
95 * @table: match_table_t describing the set of allowed option tokens and the
96 * arguments that may be associated with them. Must be terminated with a
97 * &struct match_token whose pattern is set to the NULL pointer.
98 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
99 * locations.
100 *
101 * Description: Detects which if any of a set of token strings has been passed
102 * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style
103 * format identifiers which will be taken into account when matching the
104 * tokens, and whose locations will be returned in the @args array.
105 */
106int match_token(char *s, const match_table_t table, substring_t args[])
107{
108 const struct match_token *p;
109
110 for (p = table; !match_one(s, p->pattern, args) ; p++)
111 ;
112
113 return p->token;
114}
115EXPORT_SYMBOL(match_token);
116
117/**
118 * match_number - scan a number in the given base from a substring_t
119 * @s: substring to be scanned
120 * @result: resulting integer on success
121 * @base: base to use when converting string
122 *
123 * Description: Given a &substring_t and a base, attempts to parse the substring
124 * as a number in that base.
125 *
126 * Return: On success, sets @result to the integer represented by the
127 * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
128 */
129static int match_number(substring_t *s, int *result, int base)
130{
131 char *endp;
132 char *buf;
133 int ret;
134 long val;
135
136 buf = match_strdup(s);
137 if (!buf)
138 return -ENOMEM;
139
140 ret = 0;
141 val = simple_strtol(buf, &endp, base);
142 if (endp == buf)
143 ret = -EINVAL;
144 else if (val < (long)INT_MIN || val > (long)INT_MAX)
145 ret = -ERANGE;
146 else
147 *result = (int) val;
148 kfree(buf);
149 return ret;
150}
151
152/**
153 * match_u64int - scan a number in the given base from a substring_t
154 * @s: substring to be scanned
155 * @result: resulting u64 on success
156 * @base: base to use when converting string
157 *
158 * Description: Given a &substring_t and a base, attempts to parse the substring
159 * as a number in that base.
160 *
161 * Return: On success, sets @result to the integer represented by the
162 * string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
163 */
164static int match_u64int(substring_t *s, u64 *result, int base)
165{
166 char *buf;
167 int ret;
168 u64 val;
169
170 buf = match_strdup(s);
171 if (!buf)
172 return -ENOMEM;
173
174 ret = kstrtoull(buf, base, &val);
175 if (!ret)
176 *result = val;
177 kfree(buf);
178 return ret;
179}
180
181/**
182 * match_int - scan a decimal representation of an integer from a substring_t
183 * @s: substring_t to be scanned
184 * @result: resulting integer on success
185 *
186 * Description: Attempts to parse the &substring_t @s as a decimal integer.
187 *
188 * Return: On success, sets @result to the integer represented by the string
189 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
190 */
191int match_int(substring_t *s, int *result)
192{
193 return match_number(s, result, 0);
194}
195EXPORT_SYMBOL(match_int);
196
197/**
198 * match_uint - scan a decimal representation of an integer from a substring_t
199 * @s: substring_t to be scanned
200 * @result: resulting integer on success
201 *
202 * Description: Attempts to parse the &substring_t @s as a decimal integer.
203 *
204 * Return: On success, sets @result to the integer represented by the string
205 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
206 */
207int match_uint(substring_t *s, unsigned int *result)
208{
209 int err = -ENOMEM;
210 char *buf = match_strdup(s);
211
212 if (buf) {
213 err = kstrtouint(buf, 10, result);
214 kfree(buf);
215 }
216 return err;
217}
218EXPORT_SYMBOL(match_uint);
219
220/**
221 * match_u64 - scan a decimal representation of a u64 from
222 * a substring_t
223 * @s: substring_t to be scanned
224 * @result: resulting unsigned long long on success
225 *
226 * Description: Attempts to parse the &substring_t @s as a long decimal
227 * integer.
228 *
229 * Return: On success, sets @result to the integer represented by the string
230 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
231 */
232int match_u64(substring_t *s, u64 *result)
233{
234 return match_u64int(s, result, 0);
235}
236EXPORT_SYMBOL(match_u64);
237
238/**
239 * match_octal - scan an octal representation of an integer from a substring_t
240 * @s: substring_t to be scanned
241 * @result: resulting integer on success
242 *
243 * Description: Attempts to parse the &substring_t @s as an octal integer.
244 *
245 * Return: On success, sets @result to the integer represented by the string
246 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
247 */
248int match_octal(substring_t *s, int *result)
249{
250 return match_number(s, result, 8);
251}
252EXPORT_SYMBOL(match_octal);
253
254/**
255 * match_hex - scan a hex representation of an integer from a substring_t
256 * @s: substring_t to be scanned
257 * @result: resulting integer on success
258 *
259 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
260 *
261 * Return: On success, sets @result to the integer represented by the string
262 * and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
263 */
264int match_hex(substring_t *s, int *result)
265{
266 return match_number(s, result, 16);
267}
268EXPORT_SYMBOL(match_hex);
269
270/**
271 * match_wildcard - parse if a string matches given wildcard pattern
272 * @pattern: wildcard pattern
273 * @str: the string to be parsed
274 *
275 * Description: Parse the string @str to check if matches wildcard
276 * pattern @pattern. The pattern may contain two types of wildcards:
277 * '*' - matches zero or more characters
278 * '?' - matches one character
279 *
280 * Return: If the @str matches the @pattern, return true, else return false.
281 */
282bool match_wildcard(const char *pattern, const char *str)
283{
284 const char *s = str;
285 const char *p = pattern;
286 bool star = false;
287
288 while (*s) {
289 switch (*p) {
290 case '?':
291 s++;
292 p++;
293 break;
294 case '*':
295 star = true;
296 str = s;
297 if (!*++p)
298 return true;
299 pattern = p;
300 break;
301 default:
302 if (*s == *p) {
303 s++;
304 p++;
305 } else {
306 if (!star)
307 return false;
308 str++;
309 s = str;
310 p = pattern;
311 }
312 break;
313 }
314 }
315
316 if (*p == '*')
317 ++p;
318 return !*p;
319}
320EXPORT_SYMBOL(match_wildcard);
321
322/**
323 * match_strlcpy - Copy the characters from a substring_t to a sized buffer
324 * @dest: where to copy to
325 * @src: &substring_t to copy
326 * @size: size of destination buffer
327 *
328 * Description: Copy the characters in &substring_t @src to the
329 * c-style string @dest. Copy no more than @size - 1 characters, plus
330 * the terminating NUL.
331 *
332 * Return: length of @src.
333 */
334size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
335{
336 size_t ret = src->to - src->from;
337
338 if (size) {
339 size_t len = ret >= size ? size - 1 : ret;
340 memcpy(dest, src->from, len);
341 dest[len] = '\0';
342 }
343 return ret;
344}
345EXPORT_SYMBOL(match_strlcpy);
346
347/**
348 * match_strdup - allocate a new string with the contents of a substring_t
349 * @s: &substring_t to copy
350 *
351 * Description: Allocates and returns a string filled with the contents of
352 * the &substring_t @s. The caller is responsible for freeing the returned
353 * string with kfree().
354 *
355 * Return: the address of the newly allocated NUL-terminated string or
356 * %NULL on error.
357 */
358char *match_strdup(const substring_t *s)
359{
360 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
361}
362EXPORT_SYMBOL(match_strdup);