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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/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 | */ | |
25 | static 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 | */ | |
106 | int 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 | */ | |
126 | static 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 | */ | |
155 | int 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 | */ | |
169 | int 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 | */ | |
183 | int 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 | */ | |
198 | size_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 | */ | |
218 | char *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 | ||
227 | EXPORT_SYMBOL(match_token); | |
228 | EXPORT_SYMBOL(match_int); | |
229 | EXPORT_SYMBOL(match_octal); | |
230 | EXPORT_SYMBOL(match_hex); | |
231 | EXPORT_SYMBOL(match_strlcpy); | |
232 | EXPORT_SYMBOL(match_strdup); |