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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 */
34static 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(*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 */
115int 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->pattern, args) ; p++)
120 ;
121
122 return p->token;
123}
124EXPORT_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 */
138static 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 */
170static 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(buf, base, &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 */
194int match_int(substring_t *s, int *result)
195{
196 return match_number(s, result, 0);
197}
198EXPORT_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 */
210int 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(buf, 10, result);
218}
219EXPORT_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 */
233int match_u64(substring_t *s, u64 *result)
234{
235 return match_u64int(s, result, 0);
236}
237EXPORT_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 */
249int match_octal(substring_t *s, int *result)
250{
251 return match_number(s, result, 8);
252}
253EXPORT_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 */
265int match_hex(substring_t *s, int *result)
266{
267 return match_number(s, result, 16);
268}
269EXPORT_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 */
283bool 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}
321EXPORT_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 */
335size_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}
346EXPORT_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 */
359char *match_strdup(const substring_t *s)
360{
361 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
362}
363EXPORT_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/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. On success, sets @result to the integer represented
124 * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
125 */
126static int match_number(substring_t *s, int *result, int base)
127{
128 char *endp;
129 char *buf;
130 int ret;
131 long val;
132
133 buf = match_strdup(s);
134 if (!buf)
135 return -ENOMEM;
136
137 ret = 0;
138 val = simple_strtol(buf, &endp, base);
139 if (endp == buf)
140 ret = -EINVAL;
141 else if (val < (long)INT_MIN || val > (long)INT_MAX)
142 ret = -ERANGE;
143 else
144 *result = (int) val;
145 kfree(buf);
146 return ret;
147}
148
149/**
150 * match_u64int: scan a number in the given base from a substring_t
151 * @s: substring to be scanned
152 * @result: resulting u64 on success
153 * @base: base to use when converting string
154 *
155 * Description: Given a &substring_t and a base, attempts to parse the substring
156 * as a number in that base. On success, sets @result to the integer represented
157 * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
158 */
159static int match_u64int(substring_t *s, u64 *result, int base)
160{
161 char *buf;
162 int ret;
163 u64 val;
164
165 buf = match_strdup(s);
166 if (!buf)
167 return -ENOMEM;
168
169 ret = kstrtoull(buf, base, &val);
170 if (!ret)
171 *result = val;
172 kfree(buf);
173 return ret;
174}
175
176/**
177 * match_int: - scan a decimal representation of an integer from a substring_t
178 * @s: substring_t to be scanned
179 * @result: resulting integer on success
180 *
181 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
182 * success, sets @result to the integer represented by the string and returns 0.
183 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
184 */
185int match_int(substring_t *s, int *result)
186{
187 return match_number(s, result, 0);
188}
189EXPORT_SYMBOL(match_int);
190
191/**
192 * match_u64: - scan a decimal representation of a u64 from
193 * a substring_t
194 * @s: substring_t to be scanned
195 * @result: resulting unsigned long long on success
196 *
197 * Description: Attempts to parse the &substring_t @s as a long decimal
198 * integer. On success, sets @result to the integer represented by the
199 * string and returns 0.
200 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
201 */
202int match_u64(substring_t *s, u64 *result)
203{
204 return match_u64int(s, result, 0);
205}
206EXPORT_SYMBOL(match_u64);
207
208/**
209 * match_octal: - scan an octal representation of an integer from a substring_t
210 * @s: substring_t to be scanned
211 * @result: resulting integer on success
212 *
213 * Description: Attempts to parse the &substring_t @s as an octal integer. On
214 * success, sets @result to the integer represented by the string and returns
215 * 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
216 */
217int match_octal(substring_t *s, int *result)
218{
219 return match_number(s, result, 8);
220}
221EXPORT_SYMBOL(match_octal);
222
223/**
224 * match_hex: - scan a hex representation of an integer from a substring_t
225 * @s: substring_t to be scanned
226 * @result: resulting integer on success
227 *
228 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
229 * On success, sets @result to the integer represented by the string and
230 * returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
231 */
232int match_hex(substring_t *s, int *result)
233{
234 return match_number(s, result, 16);
235}
236EXPORT_SYMBOL(match_hex);
237
238/**
239 * match_wildcard: - parse if a string matches given wildcard pattern
240 * @pattern: wildcard pattern
241 * @str: the string to be parsed
242 *
243 * Description: Parse the string @str to check if matches wildcard
244 * pattern @pattern. The pattern may contain two type wildcardes:
245 * '*' - matches zero or more characters
246 * '?' - matches one character
247 * If it's matched, return true, else return false.
248 */
249bool match_wildcard(const char *pattern, const char *str)
250{
251 const char *s = str;
252 const char *p = pattern;
253 bool star = false;
254
255 while (*s) {
256 switch (*p) {
257 case '?':
258 s++;
259 p++;
260 break;
261 case '*':
262 star = true;
263 str = s;
264 if (!*++p)
265 return true;
266 pattern = p;
267 break;
268 default:
269 if (*s == *p) {
270 s++;
271 p++;
272 } else {
273 if (!star)
274 return false;
275 str++;
276 s = str;
277 p = pattern;
278 }
279 break;
280 }
281 }
282
283 if (*p == '*')
284 ++p;
285 return !*p;
286}
287EXPORT_SYMBOL(match_wildcard);
288
289/**
290 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer
291 * @dest: where to copy to
292 * @src: &substring_t to copy
293 * @size: size of destination buffer
294 *
295 * Description: Copy the characters in &substring_t @src to the
296 * c-style string @dest. Copy no more than @size - 1 characters, plus
297 * the terminating NUL. Return length of @src.
298 */
299size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
300{
301 size_t ret = src->to - src->from;
302
303 if (size) {
304 size_t len = ret >= size ? size - 1 : ret;
305 memcpy(dest, src->from, len);
306 dest[len] = '\0';
307 }
308 return ret;
309}
310EXPORT_SYMBOL(match_strlcpy);
311
312/**
313 * match_strdup: - allocate a new string with the contents of a substring_t
314 * @s: &substring_t to copy
315 *
316 * Description: Allocates and returns a string filled with the contents of
317 * the &substring_t @s. The caller is responsible for freeing the returned
318 * string with kfree().
319 */
320char *match_strdup(const substring_t *s)
321{
322 return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
323}
324EXPORT_SYMBOL(match_strdup);