2 * lib/parser.c - simple parser for mount, etc. options.
4 * This source code is licensed under the GNU General Public License,
5 * Version 2. See the file COPYING for more details.
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>
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
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.
25 static int match_one(char *s
, const char *p
, substring_t args
[])
35 meta
= strchr(p
, '%');
37 return strcmp(p
, s
) == 0;
39 if (strncmp(p
, s
, meta
-p
))
46 len
= simple_strtoul(p
, (char **) &p
, 10);
54 if (argc
>= MAX_OPT_ARGS
)
60 size_t str_len
= strlen(s
);
64 if (len
== -1 || len
> str_len
)
66 args
[argc
].to
= s
+ len
;
70 simple_strtol(s
, &args
[argc
].to
, 0);
73 simple_strtoul(s
, &args
[argc
].to
, 0);
76 simple_strtoul(s
, &args
[argc
].to
, 8);
79 simple_strtoul(s
, &args
[argc
].to
, 16);
81 if (args
[argc
].to
== args
[argc
].from
)
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
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.
106 int match_token(char *s
, const match_table_t table
, substring_t args
[])
108 const struct match_token
*p
;
110 for (p
= table
; !match_one(s
, p
->pattern
, args
) ; p
++)
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
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.
126 static int match_number(substring_t
*s
, int *result
, int base
)
131 size_t len
= s
->to
- s
->from
;
133 buf
= kmalloc(len
+ 1, GFP_KERNEL
);
136 memcpy(buf
, s
->from
, len
);
138 *result
= simple_strtol(buf
, &endp
, base
);
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
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.
155 int match_int(substring_t
*s
, int *result
)
157 return match_number(s
, result
, 0);
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
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.
169 int match_octal(substring_t
*s
, int *result
)
171 return match_number(s
, result
, 8);
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
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.
183 int match_hex(substring_t
*s
, int *result
)
185 return match_number(s
, result
, 16);
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
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.
198 size_t match_strlcpy(char *dest
, const substring_t
*src
, size_t size
)
200 size_t ret
= src
->to
- src
->from
;
203 size_t len
= ret
>= size
? size
- 1 : ret
;
204 memcpy(dest
, src
->from
, len
);
211 * match_strdup: - allocate a new string with the contents of a substring_t
212 * @s: &substring_t to copy
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().
218 char *match_strdup(const substring_t
*s
)
220 size_t sz
= s
->to
- s
->from
+ 1;
221 char *p
= kmalloc(sz
, GFP_KERNEL
);
223 match_strlcpy(p
, s
, sz
);
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
);
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