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)
132 buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
135 memcpy(buf, s->from, s->to - s->from);
136 buf[s->to - s->from] = '\0';
137 *result = simple_strtol(buf, &endp, base);
146 * match_int: - scan a decimal representation of an integer from a substring_t
147 * @s: substring_t to be scanned
148 * @result: resulting integer on success
150 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
151 * success, sets @result to the integer represented by the string and returns 0.
152 * Returns either -ENOMEM or -EINVAL on failure.
154 int match_int(substring_t *s, int *result)
156 return match_number(s, result, 0);
160 * match_octal: - scan an octal representation of an integer from a substring_t
161 * @s: substring_t to be scanned
162 * @result: resulting integer on success
164 * Description: Attempts to parse the &substring_t @s as an octal integer. On
165 * success, sets @result to the integer represented by the string and returns
166 * 0. Returns either -ENOMEM or -EINVAL on failure.
168 int match_octal(substring_t *s, int *result)
170 return match_number(s, result, 8);
174 * match_hex: - scan a hex representation of an integer from a substring_t
175 * @s: substring_t to be scanned
176 * @result: resulting integer on success
178 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
179 * On success, sets @result to the integer represented by the string and
180 * returns 0. Returns either -ENOMEM or -EINVAL on failure.
182 int match_hex(substring_t *s, int *result)
184 return match_number(s, result, 16);
188 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer
189 * @dest: where to copy to
190 * @src: &substring_t to copy
191 * @size: size of destination buffer
193 * Description: Copy the characters in &substring_t @src to the
194 * c-style string @dest. Copy no more than @size - 1 characters, plus
195 * the terminating NUL. Return length of @src.
197 size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
199 size_t ret = src->to - src->from;
202 size_t len = ret >= size ? size - 1 : ret;
203 memcpy(dest, src->from, len);
210 * match_strdup: - allocate a new string with the contents of a substring_t
211 * @s: &substring_t to copy
213 * Description: Allocates and returns a string filled with the contents of
214 * the &substring_t @s. The caller is responsible for freeing the returned
215 * string with kfree().
217 char *match_strdup(const substring_t *s)
219 size_t sz = s->to - s->from + 1;
220 char *p = kmalloc(sz, GFP_KERNEL);
222 match_strlcpy(p, s, sz);
226 EXPORT_SYMBOL(match_token);
227 EXPORT_SYMBOL(match_int);
228 EXPORT_SYMBOL(match_octal);
229 EXPORT_SYMBOL(match_hex);
230 EXPORT_SYMBOL(match_strlcpy);
231 EXPORT_SYMBOL(match_strdup);