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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_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 */
164static 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 */
193int match_int(substring_t *s, int *result)
194{
195 return match_number(s, result, 0);
196}
197EXPORT_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 */
210int match_u64(substring_t *s, u64 *result)
211{
212 return match_u64int(s, result, 0);
213}
214EXPORT_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 */
225int match_octal(substring_t *s, int *result)
226{
227 return match_number(s, result, 8);
228}
229EXPORT_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 */
240int match_hex(substring_t *s, int *result)
241{
242 return match_number(s, result, 16);
243}
244EXPORT_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 */
257bool 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}
295EXPORT_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 */
307size_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}
318EXPORT_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 */
328char *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}
336EXPORT_SYMBOL(match_strdup);
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/module.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}
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 either -ENOMEM or -EINVAL 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 size_t len = s->to - s->from;
132
133 buf = kmalloc(len + 1, GFP_KERNEL);
134 if (!buf)
135 return -ENOMEM;
136 memcpy(buf, s->from, len);
137 buf[len] = '\0';
138 *result = simple_strtol(buf, &endp, base);
139 ret = 0;
140 if (endp == buf)
141 ret = -EINVAL;
142 kfree(buf);
143 return ret;
144}
145
146/**
147 * match_int: - scan a decimal representation of an integer from a substring_t
148 * @s: substring_t to be scanned
149 * @result: resulting integer on success
150 *
151 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
152 * success, sets @result to the integer represented by the string and returns 0.
153 * Returns either -ENOMEM or -EINVAL on failure.
154 */
155int match_int(substring_t *s, int *result)
156{
157 return match_number(s, result, 0);
158}
159
160/**
161 * match_octal: - scan an octal representation of an integer from a substring_t
162 * @s: substring_t to be scanned
163 * @result: resulting integer on success
164 *
165 * Description: Attempts to parse the &substring_t @s as an octal integer. On
166 * success, sets @result to the integer represented by the string and returns
167 * 0. Returns either -ENOMEM or -EINVAL on failure.
168 */
169int match_octal(substring_t *s, int *result)
170{
171 return match_number(s, result, 8);
172}
173
174/**
175 * match_hex: - scan a hex representation of an integer from a substring_t
176 * @s: substring_t to be scanned
177 * @result: resulting integer on success
178 *
179 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
180 * On success, sets @result to the integer represented by the string and
181 * returns 0. Returns either -ENOMEM or -EINVAL on failure.
182 */
183int match_hex(substring_t *s, int *result)
184{
185 return match_number(s, result, 16);
186}
187
188/**
189 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer
190 * @dest: where to copy to
191 * @src: &substring_t to copy
192 * @size: size of destination buffer
193 *
194 * Description: Copy the characters in &substring_t @src to the
195 * c-style string @dest. Copy no more than @size - 1 characters, plus
196 * the terminating NUL. Return length of @src.
197 */
198size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
199{
200 size_t ret = src->to - src->from;
201
202 if (size) {
203 size_t len = ret >= size ? size - 1 : ret;
204 memcpy(dest, src->from, len);
205 dest[len] = '\0';
206 }
207 return ret;
208}
209
210/**
211 * match_strdup: - allocate a new string with the contents of a substring_t
212 * @s: &substring_t to copy
213 *
214 * Description: Allocates and returns a string filled with the contents of
215 * the &substring_t @s. The caller is responsible for freeing the returned
216 * string with kfree().
217 */
218char *match_strdup(const substring_t *s)
219{
220 size_t sz = s->to - s->from + 1;
221 char *p = kmalloc(sz, GFP_KERNEL);
222 if (p)
223 match_strlcpy(p, s, sz);
224 return p;
225}
226
227EXPORT_SYMBOL(match_token);
228EXPORT_SYMBOL(match_int);
229EXPORT_SYMBOL(match_octal);
230EXPORT_SYMBOL(match_hex);
231EXPORT_SYMBOL(match_strlcpy);
232EXPORT_SYMBOL(match_strdup);