124 lines
3.5 KiB
C
124 lines
3.5 KiB
C
#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;
|
|
|
|
/*
|
|
* 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);
|