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
)
62 else if (len
== -1 || len
> strlen(s
))
64 args
[argc
].to
= s
+ len
;
67 simple_strtol(s
, &args
[argc
].to
, 0);
70 simple_strtoul(s
, &args
[argc
].to
, 0);
73 simple_strtoul(s
, &args
[argc
].to
, 8);
76 simple_strtoul(s
, &args
[argc
].to
, 16);
78 if (args
[argc
].to
== args
[argc
].from
)
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
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.
103 int match_token(char *s
, match_table_t table
, substring_t args
[])
105 const struct match_token
*p
;
107 for (p
= table
; !match_one(s
, p
->pattern
, args
) ; p
++)
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
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.
123 static int match_number(substring_t
*s
, int *result
, int base
)
129 buf
= kmalloc(s
->to
- s
->from
+ 1, GFP_KERNEL
);
132 memcpy(buf
, s
->from
, s
->to
- s
->from
);
133 buf
[s
->to
- s
->from
] = '\0';
134 *result
= simple_strtol(buf
, &endp
, base
);
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
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.
151 int match_int(substring_t
*s
, int *result
)
153 return match_number(s
, result
, 0);
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
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.
165 int match_octal(substring_t
*s
, int *result
)
167 return match_number(s
, result
, 8);
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
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.
179 int match_hex(substring_t
*s
, int *result
)
181 return match_number(s
, result
, 16);
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
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.
193 void match_strcpy(char *to
, const substring_t
*s
)
195 memcpy(to
, s
->from
, s
->to
- s
->from
);
196 to
[s
->to
- s
->from
] = '\0';
200 * match_strdup: - allocate a new string with the contents of a substring_t
201 * @s: &substring_t to copy
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().
207 char *match_strdup(const substring_t
*s
)
209 char *p
= kmalloc(s
->to
- s
->from
+ 1, GFP_KERNEL
);
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
);
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