Line data Source code
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 : */
26 19 : static int match_one(char *s, const char *p, substring_t args[])
27 : {
28 : char *meta;
29 : int argc = 0;
30 :
31 19 : if (!p)
32 : return 1;
33 :
34 : while(1) {
35 : int len = -1;
36 26 : meta = strchr(p, '%');
37 26 : if (!meta)
38 7 : return strcmp(p, s) == 0;
39 :
40 19 : if (strncmp(p, s, meta-p))
41 : return 0;
42 :
43 7 : s += meta - p;
44 7 : p = meta + 1;
45 :
46 7 : if (isdigit(*p))
47 0 : len = simple_strtoul(p, (char **) &p, 10);
48 7 : else if (*p == '%') {
49 0 : if (*s++ != '%')
50 : return 0;
51 0 : p++;
52 0 : continue;
53 : }
54 :
55 7 : if (argc >= MAX_OPT_ARGS)
56 : return 0;
57 :
58 7 : args[argc].from = s;
59 7 : switch (*p++) {
60 : case 's': {
61 0 : size_t str_len = strlen(s);
62 :
63 0 : if (str_len == 0)
64 : return 0;
65 0 : if (len == -1 || len > str_len)
66 0 : len = str_len;
67 0 : args[argc].to = s + len;
68 0 : break;
69 : }
70 : case 'd':
71 0 : simple_strtol(s, &args[argc].to, 0);
72 0 : goto num;
73 : case 'u':
74 3 : simple_strtoul(s, &args[argc].to, 0);
75 3 : goto num;
76 : case 'o':
77 4 : simple_strtoul(s, &args[argc].to, 8);
78 4 : goto num;
79 : case 'x':
80 0 : simple_strtoul(s, &args[argc].to, 16);
81 : num:
82 7 : if (args[argc].to == args[argc].from)
83 : return 0;
84 : break;
85 : default:
86 : return 0;
87 : }
88 7 : s = args[argc].to;
89 7 : 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 : */
107 7 : int match_token(char *s, const match_table_t table, substring_t args[])
108 : {
109 : const struct match_token *p;
110 :
111 7 : for (p = table; !match_one(s, p->pattern, args) ; p++)
112 : ;
113 :
114 7 : return p->token;
115 : }
116 : EXPORT_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 : */
128 7 : static int match_number(substring_t *s, int *result, int base)
129 : {
130 : char *endp;
131 : char *buf;
132 : int ret;
133 : long val;
134 7 : size_t len = s->to - s->from;
135 :
136 7 : buf = kmalloc(len + 1, GFP_KERNEL);
137 7 : if (!buf)
138 : return -ENOMEM;
139 7 : memcpy(buf, s->from, len);
140 7 : buf[len] = '\0';
141 :
142 : ret = 0;
143 7 : val = simple_strtol(buf, &endp, base);
144 7 : if (endp == buf)
145 : ret = -EINVAL;
146 : else if (val < (long)INT_MIN || val > (long)INT_MAX)
147 : ret = -ERANGE;
148 : else
149 7 : *result = (int) val;
150 7 : kfree(buf);
151 7 : 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 : */
163 3 : int match_int(substring_t *s, int *result)
164 : {
165 3 : return match_number(s, result, 0);
166 : }
167 : EXPORT_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 : */
178 4 : int match_octal(substring_t *s, int *result)
179 : {
180 4 : return match_number(s, result, 8);
181 : }
182 : EXPORT_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 : */
193 0 : int match_hex(substring_t *s, int *result)
194 : {
195 0 : return match_number(s, result, 16);
196 : }
197 : EXPORT_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 : */
210 0 : bool 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 0 : while (*s) {
217 0 : switch (*p) {
218 : case '?':
219 0 : s++;
220 0 : p++;
221 0 : break;
222 : case '*':
223 : star = true;
224 : str = s;
225 0 : if (!*++p)
226 : return true;
227 : pattern = p;
228 : break;
229 : default:
230 0 : if (*s == *p) {
231 0 : s++;
232 0 : p++;
233 : } else {
234 0 : if (!star)
235 : return false;
236 0 : str++;
237 : s = str;
238 : p = pattern;
239 : }
240 : break;
241 : }
242 : }
243 :
244 0 : if (*p == '*')
245 0 : ++p;
246 0 : return !*p;
247 : }
248 : EXPORT_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 : */
260 0 : size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
261 : {
262 0 : size_t ret = src->to - src->from;
263 :
264 0 : if (size) {
265 0 : size_t len = ret >= size ? size - 1 : ret;
266 0 : memcpy(dest, src->from, len);
267 0 : dest[len] = '\0';
268 : }
269 0 : return ret;
270 : }
271 : EXPORT_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 : */
281 0 : char *match_strdup(const substring_t *s)
282 : {
283 0 : size_t sz = s->to - s->from + 1;
284 : char *p = kmalloc(sz, GFP_KERNEL);
285 0 : if (p)
286 0 : match_strlcpy(p, s, sz);
287 0 : return p;
288 : }
289 : EXPORT_SYMBOL(match_strdup);
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