1 #include <linux/module.h> 1 #include <linux/module.h>
2 #include <linux/glob.h> 2 #include <linux/glob.h>
3 3
4 /* 4 /*
5 * The only reason this code can be compiled a 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. 6 * ATA code that depends on it can be as well. In practice, they're
7 * both usually compiled in and the module ove 7 * both usually compiled in and the module overhead goes away.
8 */ 8 */
9 MODULE_DESCRIPTION("glob(7) matching"); 9 MODULE_DESCRIPTION("glob(7) matching");
10 MODULE_LICENSE("Dual MIT/GPL"); 10 MODULE_LICENSE("Dual MIT/GPL");
11 11
12 /** 12 /**
13 * glob_match - Shell-style pattern matching, 13 * glob_match - Shell-style pattern matching, like !fnmatch(pat, str, 0)
14 * @pat: Shell-style pattern to match, e.g. "* 14 * @pat: Shell-style pattern to match, e.g. "*.[ch]".
15 * @str: String to match. The pattern must ma 15 * @str: String to match. The pattern must match the entire string.
16 * 16 *
17 * Perform shell-style glob matching, returnin 17 * Perform shell-style glob matching, returning true (1) if the match
18 * succeeds, or false (0) if it fails. Equiva 18 * succeeds, or false (0) if it fails. Equivalent to !fnmatch(@pat, @str, 0).
19 * 19 *
20 * Pattern metacharacters are ?, *, [ and \. 20 * Pattern metacharacters are ?, *, [ and \.
21 * (And, inside character classes, !, - and ]. 21 * (And, inside character classes, !, - and ].)
22 * 22 *
23 * This is small and simple implementation int 23 * This is small and simple implementation intended for device blacklists
24 * where a string is matched against a number 24 * where a string is matched against a number of patterns. Thus, it
25 * does not preprocess the patterns. It is no 25 * does not preprocess the patterns. It is non-recursive, and run-time
26 * is at most quadratic: strlen(@str)*strlen(@ 26 * is at most quadratic: strlen(@str)*strlen(@pat).
27 * 27 *
28 * An example of the worst case is glob_match( 28 * An example of the worst case is glob_match("*aaaaa", "aaaaaaaaaa");
29 * it takes 6 passes over the pattern before m 29 * it takes 6 passes over the pattern before matching the string.
30 * 30 *
31 * Like !fnmatch(@pat, @str, 0) and unlike the 31 * Like !fnmatch(@pat, @str, 0) and unlike the shell, this does NOT
32 * treat / or leading . specially; it isn't ac 32 * treat / or leading . specially; it isn't actually used for pathnames.
33 * 33 *
34 * Note that according to glob(7) (and unlike 34 * Note that according to glob(7) (and unlike bash), character classes
35 * are complemented by a leading !; this does 35 * are complemented by a leading !; this does not support the regex-style
36 * [^a-z] syntax. 36 * [^a-z] syntax.
37 * 37 *
38 * An opening bracket without a matching close 38 * An opening bracket without a matching close is matched literally.
39 */ 39 */
40 bool __pure glob_match(char const *pat, char c 40 bool __pure glob_match(char const *pat, char const *str)
41 { 41 {
42 /* 42 /*
43 * Backtrack to previous * on mismatch 43 * Backtrack to previous * on mismatch and retry starting one
44 * character later in the string. Bec 44 * character later in the string. Because * matches all characters
45 * (no exception for /), it can be eas 45 * (no exception for /), it can be easily proved that there's
46 * never a need to backtrack multiple 46 * never a need to backtrack multiple levels.
47 */ 47 */
48 char const *back_pat = NULL, *back_str !! 48 char const *back_pat = NULL, *back_str = back_str;
49 49
50 /* 50 /*
51 * Loop over each token (character or 51 * Loop over each token (character or class) in pat, matching
52 * it against the remaining unmatched 52 * it against the remaining unmatched tail of str. Return false
53 * on mismatch, or true after matching 53 * on mismatch, or true after matching the trailing nul bytes.
54 */ 54 */
55 for (;;) { 55 for (;;) {
56 unsigned char c = *str++; 56 unsigned char c = *str++;
57 unsigned char d = *pat++; 57 unsigned char d = *pat++;
58 58
59 switch (d) { 59 switch (d) {
60 case '?': /* Wildcard: a 60 case '?': /* Wildcard: anything but nul */
61 if (c == '\0') 61 if (c == '\0')
62 return false; 62 return false;
63 break; 63 break;
64 case '*': /* Any-length 64 case '*': /* Any-length wildcard */
65 if (*pat == '\0') 65 if (*pat == '\0') /* Optimize trailing * case */
66 return true; 66 return true;
67 back_pat = pat; 67 back_pat = pat;
68 back_str = --str; 68 back_str = --str; /* Allow zero-length match */
69 break; 69 break;
70 case '[': { /* Character c 70 case '[': { /* Character class */
71 bool match = false, in 71 bool match = false, inverted = (*pat == '!');
72 char const *class = pa 72 char const *class = pat + inverted;
73 unsigned char a = *cla 73 unsigned char a = *class++;
74 74
75 /* 75 /*
76 * Iterate over each s 76 * Iterate over each span in the character class.
77 * A span is either a 77 * A span is either a single character a, or a
78 * range a-b. The fir 78 * range a-b. The first span may begin with ']'.
79 */ 79 */
80 do { 80 do {
81 unsigned char 81 unsigned char b = a;
82 82
83 if (a == '\0') 83 if (a == '\0') /* Malformed */
84 goto l 84 goto literal;
85 85
86 if (class[0] = 86 if (class[0] == '-' && class[1] != ']') {
87 b = cl 87 b = class[1];
88 88
89 if (b 89 if (b == '\0')
90 90 goto literal;
91 91
92 class 92 class += 2;
93 /* Any 93 /* Any special action if a > b? */
94 } 94 }
95 match |= (a <= 95 match |= (a <= c && c <= b);
96 } while ((a = *class++ 96 } while ((a = *class++) != ']');
97 97
98 if (match == inverted) 98 if (match == inverted)
99 goto backtrack 99 goto backtrack;
100 pat = class; 100 pat = class;
101 } 101 }
102 break; 102 break;
103 case '\\': 103 case '\\':
104 d = *pat++; 104 d = *pat++;
105 fallthrough; !! 105 /*FALLTHROUGH*/
106 default: /* Literal cha 106 default: /* Literal character */
107 literal: 107 literal:
108 if (c == d) { 108 if (c == d) {
109 if (d == '\0') 109 if (d == '\0')
110 return 110 return true;
111 break; 111 break;
112 } 112 }
113 backtrack: 113 backtrack:
114 if (c == '\0' || !back 114 if (c == '\0' || !back_pat)
115 return false; 115 return false; /* No point continuing */
116 /* Try again from last 116 /* Try again from last *, one character later in str. */
117 pat = back_pat; 117 pat = back_pat;
118 str = ++back_str; 118 str = ++back_str;
119 break; 119 break;
120 } 120 }
121 } 121 }
122 } 122 }
123 EXPORT_SYMBOL(glob_match); 123 EXPORT_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 */
>> 132 static bool verbose = false;
>> 133 module_param(verbose, bool, 0);
>> 134
>> 135 struct glob_test {
>> 136 char const *pat, *str;
>> 137 bool expected;
>> 138 };
>> 139
>> 140 static 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 ''.
>> 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 */
>> 178 static char const glob_tests[] __initconst =
>> 179 /* Some basic tests */
>> 180 "1" "a\0" "a\0"
>> 181 "" "a\0" "b\0"
>> 182 "" "a\0" "aa\0"
>> 183 "" "a\0" "\0"
>> 184 "1" "\0" "\0"
>> 185 "" "\0" "a\0"
>> 186 /* Simple character class tests */
>> 187 "1" "[a]\0" "a\0"
>> 188 "" "[a]\0" "b\0"
>> 189 "" "[!a]\0" "a\0"
>> 190 "1" "[!a]\0" "b\0"
>> 191 "1" "[ab]\0" "a\0"
>> 192 "1" "[ab]\0" "b\0"
>> 193 "" "[ab]\0" "c\0"
>> 194 "1" "[!ab]\0" "c\0"
>> 195 "1" "[a-c]\0" "b\0"
>> 196 "" "[a-c]\0" "d\0"
>> 197 /* Corner cases in character class parsing */
>> 198 "1" "[a-c-e-g]\0" "-\0"
>> 199 "" "[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 "" "[]a-ceg-ik[]\0" "f\0"
>> 206 "" "[!]a-ceg-ik[]\0" "h\0"
>> 207 "" "[!]a-ceg-ik[]\0" "]\0"
>> 208 "1" "[!]a-ceg-ik[]\0" "f\0"
>> 209 /* Simple wild cards */
>> 210 "1" "?\0" "a\0"
>> 211 "" "?\0" "aa\0"
>> 212 "" "??\0" "a\0"
>> 213 "1" "?x?\0" "axb\0"
>> 214 "" "?x?\0" "abx\0"
>> 215 "" "?x?\0" "xab\0"
>> 216 /* Asterisk wild cards (backtracking) */
>> 217 "" "*??\0" "a\0"
>> 218 "1" "*??\0" "ab\0"
>> 219 "1" "*??\0" "abc\0"
>> 220 "1" "*??\0" "abcd\0"
>> 221 "" "??*\0" "a\0"
>> 222 "1" "??*\0" "ab\0"
>> 223 "1" "??*\0" "abc\0"
>> 224 "1" "??*\0" "abcd\0"
>> 225 "" "?*?\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 "" "*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 "" "*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 "" "*abcd*\0" "abcabcabcabcefg\0"
>> 248 "" "*ab*cd*\0" "abcabcabcabcefg\0";
>> 249
>> 250 static 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 '' 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 */
>> 282 static void __exit glob_fini(void) { }
>> 283
>> 284 module_init(glob_init);
>> 285 module_exit(glob_fini);
>> 286
>> 287 #endif /* CONFIG_GLOB_SELFTEST */
124 288
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