2 * IRC - Internet Relay Chat, common/match.c
3 * Copyright (C) 1990 Jarkko Oikarinen
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 1, or (at your option)
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 * @brief Functions to match strings against IRC mask strings.
21 * @version $Id: match.c 1891 2008-11-18 02:30:15Z entrope $
26 #include "ircd_chattr.h"
27 #include "ircd_string.h"
28 #include "ircd_snprintf.h"
33 * Written by Run (carlo@runaway.xs4all.nl), 25-10-96
36 * From: Carlo Wood <carlo@runaway.xs4all.nl>
37 * Message-Id: <199609021026.MAA02393@runaway.xs4all.nl>
38 * Subject: [C-Com] Analysis for `mmatch' (was: gline4 problem)
39 * To: coder-com@mail.undernet.org (coder committee)
40 * Date: Mon, 2 Sep 1996 12:26:01 +0200 (MET DST)
42 * We need a new function `mmatch(const char *old_mask, const char *new_mask)'
43 * which returns `true' likewise the current `match' (start with copying it),
44 * but which treats '*' and '?' in `new_mask' differently (not "\*" and "\?" !)
45 * as follows: a '*' in `new_mask' does not match a '?' in `old_mask' and
46 * a '?' in `new_mask' does not match a '\?' in `old_mask'.
47 * And ofcourse... a '*' in `new_mask' does not match a '\*' in `old_mask'...
48 * And last but not least, '\?' and '\*' in `new_mask' now become one character.
51 /** Compares one mask against another.
52 * One wildcard mask may be said to be a superset of another if the
53 * set of strings matched by the first is a proper superset of the set
54 * of strings matched by the second. In practical terms, this means
55 * that the second is made redundant by the first.
57 * The logic for this test is similar to that in match(), but a
58 * backslash in old_mask only matches a backslash in new_mask (and
59 * requires the next character to match exactly), and -- after
60 * contiguous runs of wildcards are logically collapsed -- a '?' in
61 * old_mask does not match a '*' in new_mask.
63 * @param[in] old_mask One wildcard mask.
64 * @param[in] new_mask Another wildcard mask.
65 * @return Zero if \a old_mask is a superset of \a new_mask, non-zero otherwise.
67 int mmatch(const char *old_mask, const char *new_mask)
69 const char *m = old_mask;
70 const char *n = new_mask;
91 for (m--; (m > old_mask) && (*m == '?'); m--)
93 if ((*m == '*') && (m > old_mask) && (m[-1] != '\\'))
99 /* Added to `mmatch' : Because '\?' and '\*' now is one character: */
100 if ((*na == '\\') && ((na[1] == '*') || (na[1] == '?')))
111 if ((*m == '\\') && ((m[1] == '*') || (m[1] == '?')))
119 /* Added to `mmatch' : Because '\?' and '\*' now is one character: */
120 if ((*n == '\\') && ((n[1] == '*') || (n[1] == '?')))
129 * This `if' has been changed compared to match() to do the following:
131 * old (m) new (n) boolean expression
132 * * any (*m == '*' && !mq) ||
133 * ? any except '*' (*m == '?' && !mq && (*n != '*' || nq)) ||
134 * any except * or ? same as m (!((*m == '*' || *m == '?') && !mq) &&
135 * ToLower(*m) == ToLower(*n) &&
136 * !((mq && !nq) || (!mq && nq)))
138 * Here `any' also includes \* and \? !
140 * After reworking the boolean expressions, we get:
141 * (Optimized to use boolean short-circuits, with most frequently occurring
142 * cases upfront (which took 2 hours!)).
144 if ((*m == '*' && !mq) ||
145 ((!mq || nq) && ToLower(*m) == ToLower(*n)) ||
146 (*m == '?' && !mq && (*n != '*' || nq)))
159 /* Added to `mmatch' : Because '\?' and '\*' now is one character: */
160 if ((*na == '\\') && ((na[1] == '*') || (na[1] == '?')))
169 * Compare if a given string (name) matches the given
170 * mask (which can contain wild cards: '*' - match any
171 * number of chars, '?' - match any single character.
176 * Originally by Douglas A Lewis (dalewis@acsu.buffalo.edu)
177 * Rewritten by Timothy Vogelsang (netski), net@astrolink.org
180 /** Check a string against a mask.
181 * This test checks using traditional IRC wildcards only: '*' means
182 * match zero or more characters of any type; '?' means match exactly
183 * one character of any type. A backslash escapes the next character
184 * so that a wildcard may be matched exactly.
185 * @param[in] mask Wildcard-containing mask.
186 * @param[in] name String to check against \a mask.
187 * @return Zero if \a mask matches \a name, non-zero if no match.
189 int match(const char *mask, const char *name)
191 const char *m = mask, *n = name;
192 const char *m_tmp = mask, *n_tmp = name;
195 for (;;) switch (*m) {
209 /* allow escaping to force capitalization */
214 for (star_p = 0; ; m++) {
217 else if (*m == '?') {
225 else if (*m == '\\') {
229 for (n_tmp = n; *n && *n != *m; n++) ;
232 for (n_tmp = n; *n && ToLower(*n) != ToLower(*m); n++) ;
235 /* and fall through */
239 if (ToLower(*m) != ToLower(*n))
249 * Collapse a pattern string into minimal components.
250 * This particular version is "in place", so that it changes the pattern
251 * which is to be reduced to a "minimal" size.
253 * (C) Carlo Wood - 6 Oct 1998
254 * Speedup rewrite by Andrea Cocito, December 1998.
255 * Note that this new optimized algorithm can *only* work in place.
258 /** Collapse a mask string to remove redundancies.
259 * Specifically, it replaces a sequence of '*' followed by additional
260 * '*' or '?' with the same number of '?'s as the input, followed by
261 * one '*'. This minimizes useless backtracking when matching later.
262 * @param[in,out] mask Mask string to collapse.
263 * @return Pointer to the start of the string.
265 char *collapse(char *mask)
275 if ((*m == '*') && ((m[1] == '*') || (m[1] == '?')))
284 if (star && (*m != '?'))
290 if ((*m == '\\') && ((m[1] == '*') || (m[1] == '?')))
299 if ((*m == '\\') && ((m[1] == '*') || (m[1] == '?')))
309 ***************** Nemesi's matchcomp() / matchexec() **************
312 /** @page compiledmasks Compiled Masks
313 * These functions allow the use of "compiled" masks, you compile a mask
314 * by means of matchcomp() that gets the plain text mask as input and writes
315 * its result in the memory locations addressed by the 3 parameters:
316 * - *cmask will contain the text of the compiled mask
317 * - *minlen will contain the length of the shortest string that can match
319 * - *charset will contain the minimal set of chars needed to match the mask
320 * You can pass NULL as *charset and it will be simply not returned, but you
321 * MUST pass valid pointers for *minlen and *cmask (which must be big enough
322 * to contain the compiled mask text that is in the worst case as long as the
323 * text of the mask itself in plaintext format) and the return value of
324 * matchcomp() will be the number of chars actually written there (excluded
325 * the trailing zero). cmask can be == mask, matchcomp() can work in place.
326 * The {cmask, minlen} couple of values make the real compiled mask and
327 * need to be passed to the functions that use the compiled mask, if you pass
328 * the wrong minlen or something wrong in cmask to one of these expect a
329 * coredump. This means that when you record a compiled mask you must store
330 * *both* these values.
331 * Once compiled the mask can be used to match a string by means of
332 * matchexec(), it can be printed back to human-readable format by means
333 * of sprintmatch() or it can be compared to another compiled mask by means
334 * of mmexec() that will tell if it completely overrides that mask (a lot like
335 * what mmatch() does for plain text masks).
336 * You can gain a lot of speed in many situations avoiding to matchexec() when:
337 * - The maximum length of the field you are about to match() the mask to is
338 * shorter than minlen, in example when matching abc*def*ghil with a nick:
339 * It just cannot match since a nick is at most 9 chars long and the mask
340 * needs at least 10 chars (10 will be the value returned in minlen).
341 * - The charset allowed for the field you are about to match to doesn't
342 * "contain" the charset returned by matchcomp(), in example when you
343 * have *.* as mask it makes no sense to try to match it against a nick
344 * because, again, a nick can't contain a '.', you can check this with
345 * a simple (charset & NTL_IRCNK) in this case.
346 * - As a special case, since compiled masks are forced to lowercase,
347 * it would make no sense to use the NTL_LOWER and NTL_UPPER on a compiled
348 * mask, thus they are reused as follows: if the NTL_LOWER bit of charset
349 * is set it means that the mask contains only non-wilds chars (i.e. you can
350 * use strCasecmp() to match it or a direct hash lookup), if the NTL_UPPER
351 * bit is set it means that it contains only wild chars (and you can
352 * match it with strlen(field)>=minlen).
353 * Do these optimizations ONLY when the data you are about to pass to
354 * matchexec() are *known* to be invalid in advance, using strChattr()
355 * or strlen() on the text would be slower than calling matchexec() directly
357 * Internally a compiled mask contain in the *cmask area the text of
358 * the plain text form of the mask itself with applied the following hacks:
359 * - All characters are forced to lowercase (so that uppercase letters and
360 * specifically the symbols 'A' and 'Z' are reserved for special use)
361 * - All non-escaped stars '*' are replaced by the letter 'Z'
362 * - All non-escaped question marks '?' are replaced by the letter 'A'
363 * - All escape characters are removed, the wilds escaped by them are
364 * then passed by without the escape since they don't collide anymore
365 * with the real wilds (encoded as A/Z)
366 * - Finally the part of the mask that follows the last asterisk is
367 * reversed (byte order mirroring) and moved right after the first
369 * After all this a mask like: Head*CHUNK1*chu\*nK2*ch??k3*TaIl
370 * .... becomes: headZliatZchunk1Zchu*nk2ZchAAk3
371 * This can still be printed on a console, more or less understood by an
372 * human and handled with the usual str*() library functions.
373 * When you store somewhere the compiled mask you can avoid storing the
374 * textform of it since it can be "decompiled" by means of sprintmatch(),
375 * but at that time the following things are changed in the mask:
376 * - All chars have been forced to lowercase.
377 * - The mask is collapsed.
378 * The balance point of using compiled masks in terms of CPU is when you expect
379 * to use matchexec() instead of match() at least 20 times on the same mask
380 * or when you expect to use mmexec() instead of mmatch() 3 times.
383 /** Compile a mask for faster matching.
384 * See also @ref compiledmasks.
385 * @param[out] cmask Output buffer for compiled mask.
386 * @param[out] minlen Minimum length of matching strings.
387 * @param[out] charset Character attributes used in compiled mask.
388 * @param[out] mask Input mask.
389 * @return Length of compiled mask, not including NUL terminator.
391 int matchcomp(char *cmask, int *minlen, int *charset, const char *mask)
393 const char *m = mask;
398 int l1, l2, lmin, loop, sign;
403 int chset2 = (NTL_LOWER | NTL_UPPER);
415 chset2 &= ~NTL_LOWER;
418 if ((*m == '?') || (*m == '*'))
426 chset2 &= ~NTL_LOWER;
431 chset &= IRCD_CharAttrTab[*b++ - CHAR_MIN];
432 chset2 &= ~NTL_UPPER;
436 *charset = (chset | chset2);
447 for (x1 = ls + 1, x2 = (b - 1); x1 < x2; x1++, x2--)
456 while ((lmin = (l1 < l2) ? l1 : l2))
459 for (loop = 0; loop < lmin; loop++)
467 l1 -= (sign < 0) ? 0 : lmin;
468 l2 -= (sign > 0) ? 0 : lmin;
478 /** Compare a string to a compiled mask.
479 * If \a cmask is not from matchcomp(), or if \a minlen is not the value
480 * passed out of matchcomp(), this may core.
481 * See also @ref compiledmasks.
482 * @param[in] string String to test.
483 * @param[in] cmask Compiled mask string.
484 * @param[in] minlen Minimum length of strings that match \a cmask.
485 * @return Zero if the string matches, non-zero otherwise.
487 int matchexec(const char *string, const char *cmask, int minlen)
489 const char *s = string - 1;
490 const char *b = cmask - 1;
496 while ((ToLower(*++s) == *++b) && *s);
498 return ((*b != '\0') && ((*b++ != 'Z') || (*b != '\0')));
509 if ((trash = (s - string - minlen)) < 0)
513 while ((ToLower(*--s) == *++b) && *b && (ToLower(*--s) == *++b) && *b
514 && (ToLower(*--s) == *++b) && *b && (ToLower(*--s) == *++b) && *b);
527 while ((ToLower(*++s) != ch))
533 while ((ToLower(*++s) == *++b) && *b);
556 * Prints the human readable version of *cmask into *mask, (decompiles
558 * The area pointed by *mask MUST be big enough (the mask might be up to
559 * twice the size of its compiled form if it's made all of \? or \*, and
560 * this function can NOT work in place since it might inflate the mask)
561 * The printed mask is not identical to the one that was compiled to cmask,
562 * in fact it is 1) forced to all lowercase, 2) collapsed, both things
563 * are supposed to NOT change it's meaning.
564 * It returns the number of chars actually written to *mask;
567 /** Decompile a compiled mask into printable form.
568 * See also @ref compiledmasks.
569 * @param[out] mask Output mask buffer.
570 * @param[in] cmask Compiled mask.
571 * @return Number of characters written to \a mask.
573 int matchdecomp(char *mask, const char *cmask)
576 const char *rcm = cmask;
577 const char *begtail, *endtail;
585 for (; (*rcm != 'Z'); rcm++, rtb++)
587 if ((*rcm == '?') || (*rcm == '*'))
589 if (!((*rtb = ((*rcm == 'A') ? '?' : *rcm))))
596 while (*rcm && (*rcm != 'Z'))
621 for (rcm = endtail; (--rcm) > begtail; *rtb++ = ((*rcm == 'A') ? '?' : *rcm))
622 if ((*rcm == '?') || (*rcm == '*'))
631 * Checks if a wider compiled mask (wcm/wminlen) completely overrides
632 * a more restrict one (rcm/rminlen), basically what mmatch() does for
633 * non-compiled masks, returns 0 if the override is true (like mmatch()).
634 * "the wider overrides the restrict" means that any string that matches
635 * the restrict one _will_ also match the wider one, always.
636 * In this we behave differently from mmatch() because in example we return
637 * true for " a?*cd overrides a*bcd " for which the override happens for how
638 * we literally defined it, here mmatch() would have returned false.
639 * The original concepts and the base algorithm are copied from mmatch()
640 * written by Run (Carlo Wood), this function is written by
641 * Nemesi (Andrea Cocito)
643 /** Tests for a superset relationship between compiled masks. This
644 * function does for compiled masks what mmatch() is does for normal
646 * See also @ref compiledmasks.
647 * @param[in] wcm Compiled mask believed to be wider.
648 * @param[in] wminlen Minimum match length for \a wcm.
649 * @param[in] rcm Compiled mask believed to be restricted.
650 * @param[in] rminlen Minimum match length for \a rcm.
651 * @return Zero if \a wcm is a superset of \a rcm, non-zero if not.
653 int mmexec(const char *wcm, int wminlen, const char *rcm, int rminlen)
655 const char *w, *r, *br, *bw, *rx, *rz;
658 /* First of all rm must have enough non-stars to 'contain' wm */
659 if ((trash = rminlen - wminlen) < 0)
665 /* Let's start the game, remember that '*' is mapped to 'Z', '?'
666 is mapped to 'A' and that head?*??*?chunk*???*tail becomes
667 headAAAAZliatAAAZchunk for compiled masks */
669 /* Match the head of wm with the head of rm */
670 for (; (*r) && (*r != 'Z') && ((*w == *r) || (*w == 'A')); r++, w++);
672 while (*w == 'A') /* Eat extra '?' before '*' in wm if got '*' in rm */
674 if (*w != 'Z') /* head1<any>.. can't match head2<any>.. */
675 return ((*w) || (*r)) ? 1 : 0; /* and head<nul> matches only head<nul> */
677 return 0; /* headZ<nul> matches head<anything> */
679 /* Does rm have any stars in it ? let's check */
680 for (rx = r; *r && (*r != 'Z'); r++);
683 /* rm has no stars and thus isn't a mask but it's just a flat
684 string: special handling occurs here, note that eat must be 0 here */
689 for (; r--, (*w) && ((*w == *r) || (*w == 'A')); w++);
690 if (*w != 'Z') /* headZliat1<any> fails on head<any>2tail */
691 return (*w) ? 1 : 0; /* but headZliat<nul> matches head<any>tail */
694 /* match the chunks */
696 { /* This loop can't break but only return */
698 for (bw = w++; (*w != *rx); rx++) /* Seek the 1st char of the chunk */
699 if (--trash < 0) /* See if we can trash one more char of rm */
700 return 1; /* If not we can only fail of course */
701 for (r = ++rx, w++; (*w) && ((*w == *r) || (*w == 'A')); r++, w++);
702 if (!*w) /* Did last loop match the rest of chunk ? */
703 return 0; /* ... Yes, end of wm, matched ! */
705 { /* ... No, hit non-star */
706 w = bw; /* Rollback at beginning of chunk */
707 if (--trash < 0) /* Trashed the char where this try started */
708 return 1; /* if we can't trash more chars fail */
712 rx = r; /* Successfully matched a chunk, move rx */
713 } /* and go on with the next one */
717 /* rm has at least one '*' and thus is a 'real' mask */
718 rz = r++; /* rx = unused of head, rz = beg-tail */
720 /* Match the tail of wm (if any) against the tail of rm */
723 for (; (*w) && (*r != 'Z') && ((*w == *r) || (*w == 'A')); w++, r++);
724 if (*r == 'Z') /* extra '?' before tail are fluff, just flush 'em */
727 if (*w != 'Z') /* We aren't matching a chunk, can't rollback */
731 /* Match the chunks of wm against what remains of the head of rm */
735 for (bw++; (rx < rz) && (*bw != *rx); rx++) /* Seek the first */
736 if (--trash < 0) /* waste some trash reserve */
738 if (!(rx < rz)) /* head finished */
740 for (bw++, (br = ++rx);
741 (br < rz) && (*bw) && ((*bw == *br) || (*bw == 'A')); br++, bw++);
742 if (!(br < rz)) /* Note that we didn't use any 'eat' char yet, if */
743 while (*bw == 'A') /* there were eat-en chars the head would be over */
744 bw++, eat++; /* Happens only at end of head, and eat is still 0 */
751 { /* If we failed because we got the end of head */
752 trash -= (br - rx); /* it makes no sense to rollback, just trash */
753 if (--trash < 0) /* all the rest of the head which isn't long */
754 return 1; /* enough for this chunk and go out of this */
755 break; /* loop, then we try with the chunks of rm */
767 /* Match the unused chunks of wm against the chunks of rm */
769 for (; *r && (*r != 'Z'); r++);
776 while (eat && *r) /* the '?' we ate makes us skip as many chars */
777 if (*r++ != 'Z') /* here, but can't skip stars or trailing zero */
779 for (bw++; (*r) && (*bw != *r); r++)
780 if ((*r != 'Z') && (--trash < 0))
784 for ((br = ++r), bw++;
785 (*br) && (*br != 'Z') && ((*bw == *br) || (*bw == 'A')); br++, bw++);
794 if ((!*br) || (*r == 'Z'))
795 { /* If we hit the end of rm or a star in it */
796 trash -= (br - r); /* makes no sense to rollback within this */
797 if (trash < 0) /* same chunk of br, skip it all and then */
798 return 1; /* either rollback or break this loop if */
799 if (!*br) /* it was the end of rm */
814 /* match the remaining chunks of wm against what remains of the tail of rm */
815 r = rz - eat - 1; /* can't have <nul> or 'Z' within the tail, so just move r */
819 for (bw++; (*bw != *r); r--)
824 for ((br = --r), bw++;
825 (*bw) && (br >= rx) && ((*bw == *br) || (*bw == 'A')); br--, bw++);
841 return 1; /* Auch... something left out ? Fail */
844 /** Test whether an address matches the most significant bits of a mask.
845 * @param[in] addr Address to test.
846 * @param[in] mask Address to test against.
847 * @param[in] bits Number of bits to test.
848 * @return 0 on mismatch, 1 if bits < 128 and all bits match; -1 if
849 * bits == 128 and all bits match.
851 int ipmask_check(const struct irc_in_addr *addr, const struct irc_in_addr *mask, unsigned char bits)
855 for (k = 0; k < 8; k++) {
857 return !(htons(addr->in6_16[k] ^ mask->in6_16[k]) >> (16-bits));
858 if (addr->in6_16[k] != mask->in6_16[k])