Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
[linux-2.6.git] / lib / parser.c
blob807b2aaa33fa42488c88e1adff522fa17b4368f3
1 /*
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.
6 */
8 #include <linux/ctype.h>
9 #include <linux/types.h>
10 #include <linux/export.h>
11 #include <linux/parser.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
15 /**
16 * match_one: - Determines if a string matches a simple pattern
17 * @s: the string to examine for presence of the pattern
18 * @p: the string containing the pattern
19 * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match
20 * locations.
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.
26 static int match_one(char *s, const char *p, substring_t args[])
28 char *meta;
29 int argc = 0;
31 if (!p)
32 return 1;
34 while(1) {
35 int len = -1;
36 meta = strchr(p, '%');
37 if (!meta)
38 return strcmp(p, s) == 0;
40 if (strncmp(p, s, meta-p))
41 return 0;
43 s += meta - p;
44 p = meta + 1;
46 if (isdigit(*p))
47 len = simple_strtoul(p, (char **) &p, 10);
48 else if (*p == '%') {
49 if (*s++ != '%')
50 return 0;
51 p++;
52 continue;
55 if (argc >= MAX_OPT_ARGS)
56 return 0;
58 args[argc].from = s;
59 switch (*p++) {
60 case 's': {
61 size_t str_len = strlen(s);
63 if (str_len == 0)
64 return 0;
65 if (len == -1 || len > str_len)
66 len = str_len;
67 args[argc].to = s + len;
68 break;
70 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;
88 s = args[argc].to;
89 argc++;
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.
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.
107 int match_token(char *s, const match_table_t table, substring_t args[])
109 const struct match_token *p;
111 for (p = table; !match_one(s, p->pattern, args) ; p++)
114 return p->token;
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
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
125 * by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
127 static int match_number(substring_t *s, int *result, int base)
129 char *endp;
130 char *buf;
131 int ret;
132 long val;
133 size_t len = s->to - s->from;
135 buf = kmalloc(len + 1, GFP_KERNEL);
136 if (!buf)
137 return -ENOMEM;
138 memcpy(buf, s->from, len);
139 buf[len] = '\0';
141 ret = 0;
142 val = simple_strtol(buf, &endp, base);
143 if (endp == buf)
144 ret = -EINVAL;
145 else if (val < (long)INT_MIN || val > (long)INT_MAX)
146 ret = -ERANGE;
147 else
148 *result = (int) val;
149 kfree(buf);
150 return ret;
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
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.
160 * Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
162 int match_int(substring_t *s, int *result)
164 return match_number(s, result, 0);
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
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
174 * 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
176 int match_octal(substring_t *s, int *result)
178 return match_number(s, result, 8);
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
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
188 * returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
190 int match_hex(substring_t *s, int *result)
192 return match_number(s, result, 16);
196 * 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
201 * 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.
205 size_t match_strlcpy(char *dest, const substring_t *src, size_t size)
207 size_t ret = src->to - src->from;
209 if (size) {
210 size_t len = ret >= size ? size - 1 : ret;
211 memcpy(dest, src->from, len);
212 dest[len] = '\0';
214 return ret;
218 * match_strdup: - allocate a new string with the contents of a substring_t
219 * @s: &substring_t to copy
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().
225 char *match_strdup(const substring_t *s)
227 size_t sz = s->to - s->from + 1;
228 char *p = kmalloc(sz, GFP_KERNEL);
229 if (p)
230 match_strlcpy(p, s, sz);
231 return p;
234 EXPORT_SYMBOL(match_token);
235 EXPORT_SYMBOL(match_int);
236 EXPORT_SYMBOL(match_octal);
237 EXPORT_SYMBOL(match_hex);
238 EXPORT_SYMBOL(match_strlcpy);
239 EXPORT_SYMBOL(match_strdup);