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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05009#include <linux/types.h>
10#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/parser.h>
12#include <linux/slab.h>
13#include <linux/string.h>
14
15/**
16 * match_one: - Determines if a string matches a simple pattern
Lucas De Marchi25985ed2011-03-30 22:57:33 -030017 * @s: the string to examine for presence of the pattern
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 * @p: the string containing the pattern
19 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
20 * locations.
21 *
22 * Description: Determines if the pattern @p is present in string @s. Can only
23 * match extremely simple token=arg style patterns. If the pattern is found,
24 * the location(s) of the arguments will be returned in the @args array.
25 */
David Howellsef4533f2007-05-03 03:10:39 -070026static int match_one(char *s, const char *p, substring_t args[])
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
28 char *meta;
29 int argc = 0;
30
31 if (!p)
32 return 1;
33
34 while(1) {
35 int len = -1;
36 meta = strchr(p, '%');
37 if (!meta)
38 return strcmp(p, s) == 0;
39
40 if (strncmp(p, s, meta-p))
41 return 0;
42
43 s += meta - p;
44 p = meta + 1;
45
46 if (isdigit(*p))
David Howellsef4533f2007-05-03 03:10:39 -070047 len = simple_strtoul(p, (char **) &p, 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 else if (*p == '%') {
49 if (*s++ != '%')
50 return 0;
51 p++;
52 continue;
53 }
54
55 if (argc >= MAX_OPT_ARGS)
56 return 0;
57
58 args[argc].from = s;
59 switch (*p++) {
André Goddard Rosab5f54b02009-12-14 18:01:08 -080060 case 's': {
61 size_t str_len = strlen(s);
62
63 if (str_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 return 0;
André Goddard Rosab5f54b02009-12-14 18:01:08 -080065 if (len == -1 || len > str_len)
66 len = str_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 args[argc].to = s + len;
68 break;
André Goddard Rosab5f54b02009-12-14 18:01:08 -080069 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 case 'd':
71 simple_strtol(s, &args[argc].to, 0);
72 goto num;
73 case 'u':
74 simple_strtoul(s, &args[argc].to, 0);
75 goto num;
76 case 'o':
77 simple_strtoul(s, &args[argc].to, 8);
78 goto num;
79 case 'x':
80 simple_strtoul(s, &args[argc].to, 16);
81 num:
82 if (args[argc].to == args[argc].from)
83 return 0;
84 break;
85 default:
86 return 0;
87 }
88 s = args[argc].to;
89 argc++;
90 }
91}
92
93/**
94 * match_token: - Find a token (and optional args) in a string
95 * @s: the string to examine for token/argument pairs
96 * @table: match_table_t describing the set of allowed option tokens and the
97 * arguments that may be associated with them. Must be terminated with a
98 * &struct match_token whose pattern is set to the NULL pointer.
99 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
100 * locations.
101 *
102 * Description: Detects which if any of a set of token strings has been passed
103 * to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style
104 * format identifiers which will be taken into account when matching the
105 * tokens, and whose locations will be returned in the @args array.
106 */
Steven Whitehousea447c092008-10-13 10:46:57 +0100107int match_token(char *s, const match_table_t table, substring_t args[])
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
David Howellsef4533f2007-05-03 03:10:39 -0700109 const struct match_token *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
111 for (p = table; !match_one(s, p->pattern, args) ; p++)
112 ;
113
114 return p->token;
115}
116
117/**
118 * match_number: scan a number in the given base from a substring_t
119 * @s: substring to be scanned
120 * @result: resulting integer on success
121 * @base: base to use when converting string
122 *
123 * Description: Given a &substring_t and a base, attempts to parse the substring
124 * as a number in that base. On success, sets @result to the integer represented
Alex Elder77dd3b02012-10-04 17:13:16 -0700125 * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 */
127static int match_number(substring_t *s, int *result, int base)
128{
129 char *endp;
130 char *buf;
131 int ret;
Alex Elder77dd3b02012-10-04 17:13:16 -0700132 long val;
Namhyung Kim5d051de2010-10-26 14:23:09 -0700133 size_t len = s->to - s->from;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
Namhyung Kim5d051de2010-10-26 14:23:09 -0700135 buf = kmalloc(len + 1, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 if (!buf)
137 return -ENOMEM;
Namhyung Kim5d051de2010-10-26 14:23:09 -0700138 memcpy(buf, s->from, len);
139 buf[len] = '\0';
Alex Elder77dd3b02012-10-04 17:13:16 -0700140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 ret = 0;
Alex Elder77dd3b02012-10-04 17:13:16 -0700142 val = simple_strtol(buf, &endp, base);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 if (endp == buf)
144 ret = -EINVAL;
Alex Elder77dd3b02012-10-04 17:13:16 -0700145 else if (val < (long)INT_MIN || val > (long)INT_MAX)
146 ret = -ERANGE;
147 else
148 *result = (int) val;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 kfree(buf);
150 return ret;
151}
152
153/**
154 * match_int: - scan a decimal representation of an integer from a substring_t
155 * @s: substring_t to be scanned
156 * @result: resulting integer on success
157 *
158 * Description: Attempts to parse the &substring_t @s as a decimal integer. On
159 * success, sets @result to the integer represented by the string and returns 0.
Namjae Jeon53769622013-02-21 16:44:08 -0800160 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 */
162int match_int(substring_t *s, int *result)
163{
164 return match_number(s, result, 0);
165}
166
167/**
168 * match_octal: - scan an octal representation of an integer from a substring_t
169 * @s: substring_t to be scanned
170 * @result: resulting integer on success
171 *
172 * Description: Attempts to parse the &substring_t @s as an octal integer. On
173 * success, sets @result to the integer represented by the string and returns
Namjae Jeon53769622013-02-21 16:44:08 -0800174 * 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 */
176int match_octal(substring_t *s, int *result)
177{
178 return match_number(s, result, 8);
179}
180
181/**
182 * match_hex: - scan a hex representation of an integer from a substring_t
183 * @s: substring_t to be scanned
184 * @result: resulting integer on success
185 *
186 * Description: Attempts to parse the &substring_t @s as a hexadecimal integer.
187 * On success, sets @result to the integer represented by the string and
Namjae Jeon53769622013-02-21 16:44:08 -0800188 * returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 */
190int match_hex(substring_t *s, int *result)
191{
192 return match_number(s, result, 16);
193}
194
195/**
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600196 * match_strlcpy: - Copy the characters from a substring_t to a sized buffer
197 * @dest: where to copy to
198 * @src: &substring_t to copy
199 * @size: size of destination buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 *
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600201 * Description: Copy the characters in &substring_t @src to the
202 * c-style string @dest. Copy no more than @size - 1 characters, plus
203 * the terminating NUL. Return length of @src.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 */
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600205size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600207 size_t ret = src->to - src->from;
208
209 if (size) {
210 size_t len = ret >= size ? size - 1 : ret;
211 memcpy(dest, src->from, len);
212 dest[len] = '\0';
213 }
214 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215}
216
217/**
218 * match_strdup: - allocate a new string with the contents of a substring_t
219 * @s: &substring_t to copy
220 *
221 * Description: Allocates and returns a string filled with the contents of
222 * the &substring_t @s. The caller is responsible for freeing the returned
223 * string with kfree().
224 */
David Howellsef4533f2007-05-03 03:10:39 -0700225char *match_strdup(const substring_t *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226{
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600227 size_t sz = s->to - s->from + 1;
228 char *p = kmalloc(sz, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 if (p)
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600230 match_strlcpy(p, s, sz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 return p;
232}
233
234EXPORT_SYMBOL(match_token);
235EXPORT_SYMBOL(match_int);
236EXPORT_SYMBOL(match_octal);
237EXPORT_SYMBOL(match_hex);
Markus Armbrusterb32a09d2008-02-26 09:57:11 -0600238EXPORT_SYMBOL(match_strlcpy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239EXPORT_SYMBOL(match_strdup);