1 #include <linux/module.h>
2 #include <linux/glob.h>
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.
9 MODULE_DESCRIPTION("glob(7) matching");
10 MODULE_LICENSE("Dual MIT/GPL");
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.
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).
20 * Pattern metacharacters are ?, *, [ and \.
21 * (And, inside character classes, !, - and ].)
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).
28 * An example of the worst case is glob_match("*aaaaa", "aaaaaaaaaa");
29 * it takes 6 passes over the pattern before matching the string.
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.
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
38 * An opening bracket without a matching close is matched literally.
40 bool __pure glob_match(char const *pat, char const *str)
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.
48 char const *back_pat = NULL, *back_str = back_str;
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.
56 unsigned char c = *str++;
57 unsigned char d = *pat++;
60 case '?': /* Wildcard: anything but nul */
64 case '*': /* Any-length wildcard */
65 if (*pat == '\0') /* Optimize trailing * case */
68 back_str = --str; /* Allow zero-length match */
70 case '[': { /* Character class */
71 bool match = false, inverted = (*pat == '!');
72 char const *class = pat + inverted;
73 unsigned char a = *class++;
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 ']'.
83 if (a == '\0') /* Malformed */
86 if (class[0] == '-' && class[1] != ']') {
93 /* Any special action if a > b? */
95 match |= (a <= c && c <= b);
96 } while ((a = *class++) != ']');
98 if (match == inverted)
106 default: /* Literal character */
114 if (c == '\0' || !back_pat)
115 return false; /* No point continuing */
116 /* Try again from last *, one character later in str. */
123 EXPORT_SYMBOL(glob_match);
126 #ifdef CONFIG_GLOB_SELFTEST
128 #include <linux/printk.h>
129 #include <linux/moduleparam.h>
131 /* Boot with "glob.verbose=1" to show successful tests, too */
132 static bool verbose = false;
133 module_param(verbose, bool, 0);
136 char const *pat, *str;
140 static bool __pure __init test(char const *pat, char const *str, bool expected)
142 bool match = glob_match(pat, str);
143 bool success = match == expected;
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";
160 printk(message, pat, str, mismatch + 3*match);
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.
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
175 * The list of tests is terminated with a final '\0' instead of
176 * a glob_match result character.
178 static char const glob_tests[] __initconst =
179 /* Some basic tests */
186 /* Simple character class tests */
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 */
216 /* Asterisk wild cards (backtracking) */
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";
250 static int __init glob_init(void)
252 unsigned successes = 0;
254 char const *p = glob_tests;
255 static char const message[] __initconst =
256 KERN_INFO "glob: %u self-tests passed, %u failed\n";
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.
265 bool expected = *p++ & 1;
269 successes += test(pat, p, expected);
275 printk(message, successes, n);
277 /* What's the errno for "kernel bug detected"? Guess... */
278 return n ? -ECANCELED : 0;
281 /* We need a dummy exit function to allow unload */
282 static void __exit glob_fini(void) { }
284 module_init(glob_init);
285 module_exit(glob_fini);
287 #endif /* CONFIG_GLOB_SELFTEST */