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