1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
|
#include <linux/module.h>
#include <linux/glob.h>
/*
* The only reason this code can be compiled as a module is because the
* ATA code that depends on it can be as well. In practice, they're
* both usually compiled in and the module overhead goes away.
*/
MODULE_DESCRIPTION("glob(7) matching");
MODULE_LICENSE("Dual MIT/GPL");
/**
* glob_match - Shell-style pattern matching, like !fnmatch(pat, str, 0)
* @pat: Shell-style pattern to match, e.g. "*.[ch]".
* @str: String to match. The pattern must match the entire string.
*
* Perform shell-style glob matching, returning true (1) if the match
* succeeds, or false (0) if it fails. Equivalent to !fnmatch(@pat, @str, 0).
*
* Pattern metacharacters are ?, *, [ and \.
* (And, inside character classes, !, - and ].)
*
* This is small and simple implementation intended for device blacklists
* where a string is matched against a number of patterns. Thus, it
* does not preprocess the patterns. It is non-recursive, and run-time
* is at most quadratic: strlen(@str)*strlen(@pat).
*
* An example of the worst case is glob_match("*aaaaa", "aaaaaaaaaa");
* it takes 6 passes over the pattern before matching the string.
*
* Like !fnmatch(@pat, @str, 0) and unlike the shell, this does NOT
* treat / or leading . specially; it isn't actually used for pathnames.
*
* Note that according to glob(7) (and unlike bash), character classes
* are complemented by a leading !; this does not support the regex-style
* [^a-z] syntax.
*
* An opening bracket without a matching close is matched literally.
*/
bool __pure glob_match(char const *pat, char const *str)
{
/*
* Backtrack to previous * on mismatch and retry starting one
* character later in the string. Because * matches all characters
* (no exception for /), it can be easily proved that there's
* never a need to backtrack multiple levels.
*/
char const *back_pat = NULL, *back_str = back_str;
/*
* Loop over each token (character or class) in pat, matching
* it against the remaining unmatched tail of str. Return false
* on mismatch, or true after matching the trailing nul bytes.
*/
for (;;) {
unsigned char c = *str++;
unsigned char d = *pat++;
switch (d) {
case '?': /* Wildcard: anything but nul */
if (c == '\0')
return false;
break;
case '*': /* Any-length wildcard */
if (*pat == '\0') /* Optimize trailing * case */
return true;
back_pat = pat;
back_str = --str; /* Allow zero-length match */
break;
case '[': { /* Character class */
bool match = false, inverted = (*pat == '!');
char const *class = pat + inverted;
unsigned char a = *class++;
/*
* Iterate over each span in the character class.
* A span is either a single character a, or a
* range a-b. The first span may begin with ']'.
*/
do {
unsigned char b = a;
if (a == '\0') /* Malformed */
goto literal;
if (class[0] == '-' && class[1] != ']') {
b = class[1];
if (b == '\0')
goto literal;
class += 2;
/* Any special action if a > b? */
}
match |= (a <= c && c <= b);
} while ((a = *class++) != ']');
if (match == inverted)
goto backtrack;
pat = class;
}
break;
case '\\':
d = *pat++;
/*FALLTHROUGH*/
default: /* Literal character */
literal:
if (c == d) {
if (d == '\0')
return true;
break;
}
backtrack:
if (c == '\0' || !back_pat)
return false; /* No point continuing */
/* Try again from last *, one character later in str. */
pat = back_pat;
str = ++back_str;
break;
}
}
}
EXPORT_SYMBOL(glob_match);
#ifdef CONFIG_GLOB_SELFTEST
#include <linux/printk.h>
#include <linux/moduleparam.h>
/* Boot with "glob.verbose=1" to show successful tests, too */
static bool verbose = false;
module_param(verbose, bool, 0);
struct glob_test {
char const *pat, *str;
bool expected;
};
static bool __pure __init test(char const *pat, char const *str, bool expected)
{
bool match = glob_match(pat, str);
bool success = match == expected;
/* Can't get string literals into a particular section, so... */
static char const msg_error[] __initconst =
KERN_ERR "glob: \"%s\" vs. \"%s\": %s *** ERROR ***\n";
static char const msg_ok[] __initconst =
KERN_DEBUG "glob: \"%s\" vs. \"%s\": %s OK\n";
static char const mismatch[] __initconst = "mismatch";
char const *message;
if (!success)
message = msg_error;
else if (verbose)
message = msg_ok;
else
return success;
printk(message, pat, str, mismatch + 3*match);
return success;
}
/*
* The tests are all jammed together in one array to make it simpler
* to place that array in the .init.rodata section. The obvious
* "array of structures containing char *" has no way to force the
* pointed-to strings to be in a particular section.
*
* Anyway, a test consists of:
* 1. Expected glob_match result: '1' or '0'.
* 2. Pattern to match: null-terminated string
* 3. String to match against: null-terminated string
*
* The list of tests is terminated with a final '\0' instead of
* a glob_match result character.
*/
static char const glob_tests[] __initconst =
/* Some basic tests */
"1" "a\0" "a\0"
"0" "a\0" "b\0"
"0" "a\0" "aa\0"
"0" "a\0" "\0"
"1" "\0" "\0"
"0" "\0" "a\0"
/* Simple character class tests */
"1" "[a]\0" "a\0"
"0" "[a]\0" "b\0"
"0" "[!a]\0" "a\0"
"1" "[!a]\0" "b\0"
"1" "[ab]\0" "a\0"
"1" "[ab]\0" "b\0"
"0" "[ab]\0" "c\0"
"1" "[!ab]\0" "c\0"
"1" "[a-c]\0" "b\0"
"0" "[a-c]\0" "d\0"
/* Corner cases in character class parsing */
"1" "[a-c-e-g]\0" "-\0"
"0" "[a-c-e-g]\0" "d\0"
"1" "[a-c-e-g]\0" "f\0"
"1" "[]a-ceg-ik[]\0" "a\0"
"1" "[]a-ceg-ik[]\0" "]\0"
"1" "[]a-ceg-ik[]\0" "[\0"
"1" "[]a-ceg-ik[]\0" "h\0"
"0" "[]a-ceg-ik[]\0" "f\0"
"0" "[!]a-ceg-ik[]\0" "h\0"
"0" "[!]a-ceg-ik[]\0" "]\0"
"1" "[!]a-ceg-ik[]\0" "f\0"
/* Simple wild cards */
"1" "?\0" "a\0"
"0" "?\0" "aa\0"
"0" "??\0" "a\0"
"1" "?x?\0" "axb\0"
"0" "?x?\0" "abx\0"
"0" "?x?\0" "xab\0"
/* Asterisk wild cards (backtracking) */
"0" "*??\0" "a\0"
"1" "*??\0" "ab\0"
"1" "*??\0" "abc\0"
"1" "*??\0" "abcd\0"
"0" "??*\0" "a\0"
"1" "??*\0" "ab\0"
"1" "??*\0" "abc\0"
"1" "??*\0" "abcd\0"
"0" "?*?\0" "a\0"
"1" "?*?\0" "ab\0"
"1" "?*?\0" "abc\0"
"1" "?*?\0" "abcd\0"
"1" "*b\0" "b\0"
"1" "*b\0" "ab\0"
"0" "*b\0" "ba\0"
"1" "*b\0" "bb\0"
"1" "*b\0" "abb\0"
"1" "*b\0" "bab\0"
"1" "*bc\0" "abbc\0"
"1" "*bc\0" "bc\0"
"1" "*bc\0" "bbc\0"
"1" "*bc\0" "bcbc\0"
/* Multiple asterisks (complex backtracking) */
"1" "*ac*\0" "abacadaeafag\0"
"1" "*ac*ae*ag*\0" "abacadaeafag\0"
"1" "*a*b*[bc]*[ef]*g*\0" "abacadaeafag\0"
"0" "*a*b*[ef]*[cd]*g*\0" "abacadaeafag\0"
"1" "*abcd*\0" "abcabcabcabcdefg\0"
"1" "*ab*cd*\0" "abcabcabcabcdefg\0"
"1" "*abcd*abcdef*\0" "abcabcdabcdeabcdefg\0"
"0" "*abcd*\0" "abcabcabcabcefg\0"
"0" "*ab*cd*\0" "abcabcabcabcefg\0";
static int __init glob_init(void)
{
unsigned successes = 0;
unsigned n = 0;
char const *p = glob_tests;
static char const message[] __initconst =
KERN_INFO "glob: %u self-tests passed, %u failed\n";
/*
* Tests are jammed together in a string. The first byte is '1'
* or '0' to indicate the expected outcome, or '\0' to indicate the
* end of the tests. Then come two null-terminated strings: the
* pattern and the string to match it against.
*/
while (*p) {
bool expected = *p++ & 1;
char const *pat = p;
p += strlen(p) + 1;
successes += test(pat, p, expected);
p += strlen(p) + 1;
n++;
}
n -= successes;
printk
|