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, 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, &p, 10);
53 if (argc >= MAX_OPT_ARGS)
61 else if (len == -1 || len > strlen(s))
63 args[argc].to = s + len;
66 simple_strtol(s, &args[argc].to, 0);
69 simple_strtoul(s, &args[argc].to, 0);
72 simple_strtoul(s, &args[argc].to, 8);
75 simple_strtoul(s, &args[argc].to, 16);
77 if (args[argc].to == args[argc].from)
89 * match_token: - Find a token (and optional args) in a string
90 * @s: the string to examine for token/argument pairs
91 * @table: match_table_t describing the set of allowed option tokens and the
92 * arguments that may be associated with them. Must be terminated with a
93 * &struct match_token whose pattern is set to the NULL pointer.
94 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
97 * Description: Detects which if any of a set of token strings has been passed
98 * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
99 * format identifiers which will be taken into account when matching the
100 * tokens, and whose locations will be returned in the @args array.
102 int match_token(char *s, match_table_t table, substring_t args[])
104 struct match_token *p;
106 for (p = table; !match_one(s, p->pattern, args) ; p++)
113 * match_number: scan a number in the given base from a substring_t
114 * @s: substring to be scanned
115 * @result: resulting integer on success
116 * @base: base to use when converting string
118 * Description: Given a &substring_t and a base, attempts to parse the substring
119 * as a number in that base. On success, sets @result to the integer represented
120 * by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure.
122 static int match_number(substring_t *s, int *result, int base)
128 buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
131 memcpy(buf, s->from, s->to - s->from);
132 buf[s->to - s->from] = '\0';
133 *result = simple_strtol(buf, &endp, base);
142 * match_int: - scan a decimal representation of an integer from a substring_t
143 * @s: substring_t to be scanned
144 * @result: resulting integer on success
146 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
147 * success, sets @result to the integer represented by the string and returns 0.
148 * Returns either -ENOMEM or -EINVAL on failure.
150 int match_int(substring_t *s, int *result)
152 return match_number(s, result, 0);
156 * match_octal: - scan an octal representation of an integer from a substring_t
157 * @s: substring_t to be scanned
158 * @result: resulting integer on success
160 * Description: Attempts to parse the &substring_t @s as an octal integer. On
161 * success, sets @result to the integer represented by the string and returns
162 * 0. Returns either -ENOMEM or -EINVAL on failure.
164 int match_octal(substring_t *s, int *result)
166 return match_number(s, result, 8);
170 * match_hex: - scan a hex representation of an integer from a substring_t
171 * @s: substring_t to be scanned
172 * @result: resulting integer on success
174 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
175 * On success, sets @result to the integer represented by the string and
176 * returns 0. Returns either -ENOMEM or -EINVAL on failure.
178 int match_hex(substring_t *s, int *result)
180 return match_number(s, result, 16);
184 * match_strcpy: - copies the characters from a substring_t to a string
185 * @to: string to copy characters to.
186 * @s: &substring_t to copy
188 * Description: Copies the set of characters represented by the given
189 * &substring_t @s to the c-style string @to. Caller guarantees that @to is
190 * large enough to hold the characters of @s.
192 void match_strcpy(char *to, substring_t *s)
194 memcpy(to, s->from, s->to - s->from);
195 to[s->to - s->from] = '\0';
199 * match_strdup: - allocate a new string with the contents of a substring_t
200 * @s: &substring_t to copy
202 * Description: Allocates and returns a string filled with the contents of
203 * the &substring_t @s. The caller is responsible for freeing the returned
204 * string with kfree().
206 char *match_strdup(substring_t *s)
208 char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL);
214 EXPORT_SYMBOL(match_token);
215 EXPORT_SYMBOL(match_int);
216 EXPORT_SYMBOL(match_octal);
217 EXPORT_SYMBOL(match_hex);
218 EXPORT_SYMBOL(match_strcpy);
219 EXPORT_SYMBOL(match_strdup);