Fix a corner case of superset matching
The algorithm we're using gets stuck if it has a ? and can only see a * to feed to it, even if it could skip over that * and consume a character following it. Remedy this by rearranging the input so * always precedes ? in runs of wildcards, so when we're matching ? we know we can skip things.
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parent
bc6e29e3b0
commit
57fbf05388
2 changed files with 54 additions and 2 deletions
33
ircd/match.c
33
ircd/match.c
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@ -104,6 +104,30 @@ int match(const char *mask, const char *name)
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}
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}
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void
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match_arrange_stars(char *mask)
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{
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char *swap = NULL;
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for (char *p = mask; *p != '\0'; p++)
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{
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switch (*p)
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{
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case '*':
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if (swap == NULL) break;
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*swap++ = '*';
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*p = '?';
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break;
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case '?':
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if (swap == NULL) swap = p;
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break;
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default:
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swap = NULL;
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break;
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}
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}
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}
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/** Check a mask against a mask.
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* This test checks using traditional IRC wildcards only: '*' means
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* match zero or more characters of any type; '?' means match exactly
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@ -115,15 +139,19 @@ int match(const char *mask, const char *name)
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* @param[in] name New wildcard-containing mask.
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* @return 1 if \a name is equal to or more specific than \a mask, 0 otherwise.
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*/
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int mask_match(const char *mask, const char *name)
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int mask_match(const char *mask_, const char *name)
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{
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static char mask[BUFSIZE];
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const char *m = mask, *n = name;
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const char *m_tmp = mask, *n_tmp = name;
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int star_p;
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s_assert(mask != NULL);
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s_assert(mask_ != NULL);
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s_assert(name != NULL);
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rb_strlcpy(mask, mask_, sizeof mask);
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match_arrange_stars(mask);
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for (;;)
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{
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switch (*m)
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@ -146,6 +174,7 @@ int mask_match(const char *mask, const char *name)
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else if (*m == '?')
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{
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/* changed for mask_match() */
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while (star_p && *n == '*') n++;
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if (*n == '*' || !*n)
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goto backtrack;
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n++;
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@ -30,6 +30,8 @@
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struct Client me;
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void match_arrange_stars(char *);
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static void test_match(void)
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{
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is_int(0, match("*foo*", "bar"), MSG);
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@ -40,6 +42,7 @@ static void test_match(void)
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static void test_mask_match(void)
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{
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is_int(0, mask_match("*foo*", "bar"), MSG);
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is_int(1, mask_match("*foo*", "foo"), MSG);
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@ -63,12 +66,32 @@ static void test_mask_match(void)
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is_int(0, mask_match("??", "aaa"), MSG);
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}
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static void test_arrange_stars(void)
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{
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{
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char rearrange[] = "quick brown fox";
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match_arrange_stars(rearrange);
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is_string("quick brown fox", rearrange, MSG);
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}
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{
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char rearrange[] = "?*?*?*";
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match_arrange_stars(rearrange);
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is_string("***???", rearrange, MSG);
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}
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{
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char rearrange[] = "?*? *?*";
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match_arrange_stars(rearrange);
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is_string("*?? **?", rearrange, MSG);
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}
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}
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int main(int argc, char *argv[])
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{
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plan_lazy();
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test_match();
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test_mask_match();
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test_arrange_stars();
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return 0;
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}
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