#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(message, successes, n);
/* What's the errno for "kernel bug detected"? Guess... */
return n ? -ECANCELED : 0;
}
/* We need a dummy exit function to allow unload */
static void __exit glob_fini(void) { }
module_init(glob_init);
module_exit(glob_fini);
#endif /* CONFIG_GLOB_SELFTEST */
