blob: b6d11631231b67e330b03eae74ecdf8373073866
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 | static 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 | */ |
107 | int 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 | } |
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 | 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 | 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 | */ |
163 | int match_int(substring_t *s, int *result) |
164 | { |
165 | 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 | int match_octal(substring_t *s, int *result) |
179 | { |
180 | 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 | int match_hex(substring_t *s, int *result) |
194 | { |
195 | 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 | 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 | 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 | } |
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 | size_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 | } |
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 | char *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 | } |
289 | EXPORT_SYMBOL(match_strdup); |
290 |