]>
Commit | Line | Data |
---|---|---|
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 presense 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 | */ | |
25 | static int match_one(char *s, 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, &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 | if (strlen(s) == 0) | |
61 | return 0; | |
62 | else if (len == -1 || len > strlen(s)) | |
63 | len = strlen(s); | |
64 | args[argc].to = s + len; | |
65 | break; | |
66 | case 'd': | |
67 | simple_strtol(s, &args[argc].to, 0); | |
68 | goto num; | |
69 | case 'u': | |
70 | simple_strtoul(s, &args[argc].to, 0); | |
71 | goto num; | |
72 | case 'o': | |
73 | simple_strtoul(s, &args[argc].to, 8); | |
74 | goto num; | |
75 | case 'x': | |
76 | simple_strtoul(s, &args[argc].to, 16); | |
77 | num: | |
78 | if (args[argc].to == args[argc].from) | |
79 | return 0; | |
80 | break; | |
81 | default: | |
82 | return 0; | |
83 | } | |
84 | s = args[argc].to; | |
85 | argc++; | |
86 | } | |
87 | } | |
88 | ||
89 | /** | |
90 | * match_token: - Find a token (and optional args) in a string | |
91 | * @s: the string to examine for token/argument pairs | |
92 | * @table: match_table_t describing the set of allowed option tokens and the | |
93 | * arguments that may be associated with them. Must be terminated with a | |
94 | * &struct match_token whose pattern is set to the NULL pointer. | |
95 | * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match | |
96 | * locations. | |
97 | * | |
98 | * Description: Detects which if any of a set of token strings has been passed | |
99 | * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style | |
100 | * format identifiers which will be taken into account when matching the | |
101 | * tokens, and whose locations will be returned in the @args array. | |
102 | */ | |
103 | int match_token(char *s, match_table_t table, substring_t args[]) | |
104 | { | |
105 | struct match_token *p; | |
106 | ||
107 | for (p = table; !match_one(s, p->pattern, args) ; p++) | |
108 | ; | |
109 | ||
110 | return p->token; | |
111 | } | |
112 | ||
113 | /** | |
114 | * match_number: scan a number in the given base from a substring_t | |
115 | * @s: substring to be scanned | |
116 | * @result: resulting integer on success | |
117 | * @base: base to use when converting string | |
118 | * | |
119 | * Description: Given a &substring_t and a base, attempts to parse the substring | |
120 | * as a number in that base. On success, sets @result to the integer represented | |
121 | * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure. | |
122 | */ | |
123 | static int match_number(substring_t *s, int *result, int base) | |
124 | { | |
125 | char *endp; | |
126 | char *buf; | |
127 | int ret; | |
128 | ||
129 | buf = kmalloc(s->to - s->from + 1, GFP_KERNEL); | |
130 | if (!buf) | |
131 | return -ENOMEM; | |
132 | memcpy(buf, s->from, s->to - s->from); | |
133 | buf[s->to - s->from] = '\0'; | |
134 | *result = simple_strtol(buf, &endp, base); | |
135 | ret = 0; | |
136 | if (endp == buf) | |
137 | ret = -EINVAL; | |
138 | kfree(buf); | |
139 | return ret; | |
140 | } | |
141 | ||
142 | /** | |
143 | * match_int: - scan a decimal representation of an integer from a substring_t | |
144 | * @s: substring_t to be scanned | |
145 | * @result: resulting integer on success | |
146 | * | |
147 | * Description: Attempts to parse the &substring_t @s as a decimal integer. On | |
148 | * success, sets @result to the integer represented by the string and returns 0. | |
149 | * Returns either -ENOMEM or -EINVAL on failure. | |
150 | */ | |
151 | int match_int(substring_t *s, int *result) | |
152 | { | |
153 | return match_number(s, result, 0); | |
154 | } | |
155 | ||
156 | /** | |
157 | * match_octal: - scan an octal representation of an integer from a substring_t | |
158 | * @s: substring_t to be scanned | |
159 | * @result: resulting integer on success | |
160 | * | |
161 | * Description: Attempts to parse the &substring_t @s as an octal integer. On | |
162 | * success, sets @result to the integer represented by the string and returns | |
163 | * 0. Returns either -ENOMEM or -EINVAL on failure. | |
164 | */ | |
165 | int match_octal(substring_t *s, int *result) | |
166 | { | |
167 | return match_number(s, result, 8); | |
168 | } | |
169 | ||
170 | /** | |
171 | * match_hex: - scan a hex representation of an integer from a substring_t | |
172 | * @s: substring_t to be scanned | |
173 | * @result: resulting integer on success | |
174 | * | |
175 | * Description: Attempts to parse the &substring_t @s as a hexadecimal integer. | |
176 | * On success, sets @result to the integer represented by the string and | |
177 | * returns 0. Returns either -ENOMEM or -EINVAL on failure. | |
178 | */ | |
179 | int match_hex(substring_t *s, int *result) | |
180 | { | |
181 | return match_number(s, result, 16); | |
182 | } | |
183 | ||
184 | /** | |
185 | * match_strcpy: - copies the characters from a substring_t to a string | |
186 | * @to: string to copy characters to. | |
187 | * @s: &substring_t to copy | |
188 | * | |
189 | * Description: Copies the set of characters represented by the given | |
190 | * &substring_t @s to the c-style string @to. Caller guarantees that @to is | |
191 | * large enough to hold the characters of @s. | |
192 | */ | |
193 | void match_strcpy(char *to, substring_t *s) | |
194 | { | |
195 | memcpy(to, s->from, s->to - s->from); | |
196 | to[s->to - s->from] = '\0'; | |
197 | } | |
198 | ||
199 | /** | |
200 | * match_strdup: - allocate a new string with the contents of a substring_t | |
201 | * @s: &substring_t to copy | |
202 | * | |
203 | * Description: Allocates and returns a string filled with the contents of | |
204 | * the &substring_t @s. The caller is responsible for freeing the returned | |
205 | * string with kfree(). | |
206 | */ | |
207 | char *match_strdup(substring_t *s) | |
208 | { | |
209 | char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL); | |
210 | if (p) | |
211 | match_strcpy(p, s); | |
212 | return p; | |
213 | } | |
214 | ||
215 | EXPORT_SYMBOL(match_token); | |
216 | EXPORT_SYMBOL(match_int); | |
217 | EXPORT_SYMBOL(match_octal); | |
218 | EXPORT_SYMBOL(match_hex); | |
219 | EXPORT_SYMBOL(match_strcpy); | |
220 | EXPORT_SYMBOL(match_strdup); |