blob: 703c8c13b346c39c460d0dbe02e6f32af019d71b [file] [log] [blame]
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>
9#include <linux/module.h>
10#include <linux/parser.h>
11#include <linux/slab.h>
12#include <linux/string.h>
13
14/**
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
19 * locations.
20 *
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.
24 */
David Howellsef4533f2007-05-03 03:10:39 -070025static int match_one(char *s, const char *p, substring_t args[])
Linus Torvalds1da177e2005-04-16 15:20:36 -070026{
27 char *meta;
28 int argc = 0;
29
30 if (!p)
31 return 1;
32
33 while(1) {
34 int len = -1;
35 meta = strchr(p, '%');
36 if (!meta)
37 return strcmp(p, s) == 0;
38
39 if (strncmp(p, s, meta-p))
40 return 0;
41
42 s += meta - p;
43 p = meta + 1;
44
45 if (isdigit(*p))
David Howellsef4533f2007-05-03 03:10:39 -070046 len = simple_strtoul(p, (char **) &p, 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 else if (*p == '%') {
48 if (*s++ != '%')
49 return 0;
50 p++;
51 continue;
52 }
53
54 if (argc >= MAX_OPT_ARGS)
55 return 0;
56
57 args[argc].from = s;
58 switch (*p++) {
59 case 's':
60 if (strlen(s) == 0)
61 return 0;
62 else if (len == -1 || len > strlen(s))
63 len = strlen(s);
64 args[argc].to = s + len;
65 break;
66 case 'd':
67 simple_strtol(s, &args[argc].to, 0);
68 goto num;
69 case 'u':
70 simple_strtoul(s, &args[argc].to, 0);
71 goto num;
72 case 'o':
73 simple_strtoul(s, &args[argc].to, 8);
74 goto num;
75 case 'x':
76 simple_strtoul(s, &args[argc].to, 16);
77 num:
78 if (args[argc].to == args[argc].from)
79 return 0;
80 break;
81 default:
82 return 0;
83 }
84 s = args[argc].to;
85 argc++;
86 }
87}
88
89/**
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
96 * locations.
97 *
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.
102 */
103int match_token(char *s, match_table_t table, substring_t args[])
104{
David Howellsef4533f2007-05-03 03:10:39 -0700105 const struct match_token *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107 for (p = table; !match_one(s, p->pattern, args) ; p++)
108 ;
109
110 return p->token;
111}
112
113/**
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
118 *
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.
122 */
123static int match_number(substring_t *s, int *result, int base)
124{
125 char *endp;
126 char *buf;
127 int ret;
128
129 buf = kmalloc(s->to - s->from + 1, GFP_KERNEL);
130 if (!buf)
131 return -ENOMEM;
132 memcpy(buf, s->from, s->to - s->from);
133 buf[s->to - s->from] = '\0';
134 *result = simple_strtol(buf, &endp, base);
135 ret = 0;
136 if (endp == buf)
137 ret = -EINVAL;
138 kfree(buf);
139 return ret;
140}
141
142/**
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
146 *
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.
150 */
151int match_int(substring_t *s, int *result)
152{
153 return match_number(s, result, 0);
154}
155
156/**
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
160 *
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.
164 */
165int match_octal(substring_t *s, int *result)
166{
167 return match_number(s, result, 8);
168}
169
170/**
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
174 *
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.
178 */
179int match_hex(substring_t *s, int *result)
180{
181 return match_number(s, result, 16);
182}
183
184/**
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
188 *
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.
192 */
David Howellsef4533f2007-05-03 03:10:39 -0700193void match_strcpy(char *to, const substring_t *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194{
195 memcpy(to, s->from, s->to - s->from);
196 to[s->to - s->from] = '\0';
197}
198
199/**
200 * match_strdup: - allocate a new string with the contents of a substring_t
201 * @s: &substring_t to copy
202 *
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().
206 */
David Howellsef4533f2007-05-03 03:10:39 -0700207char *match_strdup(const substring_t *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
209 char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL);
210 if (p)
211 match_strcpy(p, s);
212 return p;
213}
214
215EXPORT_SYMBOL(match_token);
216EXPORT_SYMBOL(match_int);
217EXPORT_SYMBOL(match_octal);
218EXPORT_SYMBOL(match_hex);
219EXPORT_SYMBOL(match_strcpy);
220EXPORT_SYMBOL(match_strdup);