xref: /freebsd/lib/libc/gen/fnmatch.c (revision f5463265955b829775bbb32e1fd0bc11dafc36ce)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Guido van Rossum.
9  *
10  * Copyright (c) 2011 The FreeBSD Foundation
11  *
12  * Portions of this software were developed by David Chisnall
13  * under sponsorship from the FreeBSD Foundation.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 /*
41  * Function fnmatch() as specified in POSIX 1003.2-1992, section B.6.
42  * Compares a filename or pathname to a pattern.
43  */
44 
45 /*
46  * Some notes on multibyte character support:
47  * 1. Patterns with illegal byte sequences match nothing.
48  * 2. Illegal byte sequences in the "string" argument are handled by treating
49  *    them as single-byte characters with a value of the first byte of the
50  *    sequence cast to wchar_t.
51  * 3. Multibyte conversion state objects (mbstate_t) are passed around and
52  *    used for most, but not all, conversions. Further work will be required
53  *    to support state-dependent encodings.
54  */
55 
56 #include <fnmatch.h>
57 #include <limits.h>
58 #include <string.h>
59 #include <wchar.h>
60 #include <wctype.h>
61 
62 #include "collate.h"
63 
64 #define	EOS	'\0'
65 
66 #define RANGE_MATCH     1
67 #define RANGE_NOMATCH   0
68 #define RANGE_ERROR     (-1)
69 
70 static int rangematch(const char *, wchar_t, int, char **, mbstate_t *);
71 static int fnmatch1(const char *, const char *, const char *, int, mbstate_t,
72 		mbstate_t);
73 
74 int
75 fnmatch(const char *pattern, const char *string, int flags)
76 {
77 	static const mbstate_t initial;
78 
79 	return (fnmatch1(pattern, string, string, flags, initial, initial));
80 }
81 
82 static int
83 fnmatch1(const char *pattern, const char *string, const char *stringstart,
84     int flags, mbstate_t patmbs, mbstate_t strmbs)
85 {
86 	const char *bt_pattern, *bt_string;
87 	mbstate_t bt_patmbs, bt_strmbs;
88 	char *newp;
89 	char c;
90 	wchar_t pc, sc;
91 	size_t pclen, sclen;
92 
93 	bt_pattern = bt_string = NULL;
94 	for (;;) {
95 		pclen = mbrtowc(&pc, pattern, MB_LEN_MAX, &patmbs);
96 		if (pclen == (size_t)-1 || pclen == (size_t)-2)
97 			return (FNM_NOMATCH);
98 		pattern += pclen;
99 		sclen = mbrtowc(&sc, string, MB_LEN_MAX, &strmbs);
100 		if (sclen == (size_t)-1 || sclen == (size_t)-2) {
101 			sc = (unsigned char)*string;
102 			sclen = 1;
103 			memset(&strmbs, 0, sizeof(strmbs));
104 		}
105 		switch (pc) {
106 		case EOS:
107 			if ((flags & FNM_LEADING_DIR) && sc == '/')
108 				return (0);
109 			if (sc == EOS)
110 				return (0);
111 			goto backtrack;
112 		case '?':
113 			if (sc == EOS)
114 				return (FNM_NOMATCH);
115 			if (sc == '/' && (flags & FNM_PATHNAME))
116 				goto backtrack;
117 			if (sc == '.' && (flags & FNM_PERIOD) &&
118 			    (string == stringstart ||
119 			    ((flags & FNM_PATHNAME) && *(string - 1) == '/')))
120 				goto backtrack;
121 			string += sclen;
122 			break;
123 		case '*':
124 			c = *pattern;
125 			/* Collapse multiple stars. */
126 			while (c == '*')
127 				c = *++pattern;
128 
129 			if (sc == '.' && (flags & FNM_PERIOD) &&
130 			    (string == stringstart ||
131 			    ((flags & FNM_PATHNAME) && *(string - 1) == '/')))
132 				goto backtrack;
133 
134 			/* Optimize for pattern with * at end or before /. */
135 			if (c == EOS)
136 				if (flags & FNM_PATHNAME)
137 					return ((flags & FNM_LEADING_DIR) ||
138 					    strchr(string, '/') == NULL ?
139 					    0 : FNM_NOMATCH);
140 				else
141 					return (0);
142 			else if (c == '/' && flags & FNM_PATHNAME) {
143 				if ((string = strchr(string, '/')) == NULL)
144 					return (FNM_NOMATCH);
145 				break;
146 			}
147 
148 			/*
149 			 * First try the shortest match for the '*' that
150 			 * could work. We can forget any earlier '*' since
151 			 * there is no way having it match more characters
152 			 * can help us, given that we are already here.
153 			 */
154 			bt_pattern = pattern, bt_patmbs = patmbs;
155 			bt_string = string, bt_strmbs = strmbs;
156 			break;
157 		case '[':
158 			if (sc == EOS)
159 				return (FNM_NOMATCH);
160 			if (sc == '/' && (flags & FNM_PATHNAME))
161 				goto backtrack;
162 			if (sc == '.' && (flags & FNM_PERIOD) &&
163 			    (string == stringstart ||
164 			    ((flags & FNM_PATHNAME) && *(string - 1) == '/')))
165 				goto backtrack;
166 
167 			switch (rangematch(pattern, sc, flags, &newp,
168 			    &patmbs)) {
169 			case RANGE_ERROR:
170 				goto norm;
171 			case RANGE_MATCH:
172 				pattern = newp;
173 				break;
174 			case RANGE_NOMATCH:
175 				goto backtrack;
176 			}
177 			string += sclen;
178 			break;
179 		case '\\':
180 			if (!(flags & FNM_NOESCAPE)) {
181 				pclen = mbrtowc(&pc, pattern, MB_LEN_MAX,
182 				    &patmbs);
183 				if (pclen == 0 || pclen == (size_t)-1 ||
184 				    pclen == (size_t)-2)
185 					return (FNM_NOMATCH);
186 				pattern += pclen;
187 			}
188 			/* FALLTHROUGH */
189 		default:
190 		norm:
191 			string += sclen;
192 			if (pc == sc)
193 				;
194 			else if ((flags & FNM_CASEFOLD) &&
195 				 (towlower(pc) == towlower(sc)))
196 				;
197 			else {
198 		backtrack:
199 				/*
200 				 * If we have a mismatch (other than hitting
201 				 * the end of the string), go back to the last
202 				 * '*' seen and have it match one additional
203 				 * character.
204 				 */
205 				if (bt_pattern == NULL)
206 					return (FNM_NOMATCH);
207 				sclen = mbrtowc(&sc, bt_string, MB_LEN_MAX,
208 				    &bt_strmbs);
209 				if (sclen == (size_t)-1 ||
210 				    sclen == (size_t)-2) {
211 					sc = (unsigned char)*bt_string;
212 					sclen = 1;
213 					memset(&bt_strmbs, 0,
214 					    sizeof(bt_strmbs));
215 				}
216 				if (sc == EOS)
217 					return (FNM_NOMATCH);
218 				if (sc == '/' && flags & FNM_PATHNAME)
219 					return (FNM_NOMATCH);
220 				bt_string += sclen;
221 				pattern = bt_pattern, patmbs = bt_patmbs;
222 				string = bt_string, strmbs = bt_strmbs;
223 			}
224 			break;
225 		}
226 	}
227 	/* NOTREACHED */
228 }
229 
230 static int
231 rangematch(const char *pattern, wchar_t test, int flags, char **newp,
232     mbstate_t *patmbs)
233 {
234 	int negate, ok;
235 	wchar_t c, c2;
236 	size_t pclen;
237 	const char *origpat;
238 	struct xlocale_collate *table =
239 		(struct xlocale_collate*)__get_locale()->components[XLC_COLLATE];
240 
241 	/*
242 	 * A bracket expression starting with an unquoted circumflex
243 	 * character produces unspecified results (IEEE 1003.2-1992,
244 	 * 3.13.2).  This implementation treats it like '!', for
245 	 * consistency with the regular expression syntax.
246 	 * J.T. Conklin (conklin@ngai.kaleida.com)
247 	 */
248 	if ((negate = (*pattern == '!' || *pattern == '^')))
249 		++pattern;
250 
251 	if (flags & FNM_CASEFOLD)
252 		test = towlower(test);
253 
254 	/*
255 	 * A right bracket shall lose its special meaning and represent
256 	 * itself in a bracket expression if it occurs first in the list.
257 	 * -- POSIX.2 2.8.3.2
258 	 */
259 	ok = 0;
260 	origpat = pattern;
261 	for (;;) {
262 		if (*pattern == ']' && pattern > origpat) {
263 			pattern++;
264 			break;
265 		} else if (*pattern == '\0') {
266 			return (RANGE_ERROR);
267 		} else if (*pattern == '/' && (flags & FNM_PATHNAME)) {
268 			return (RANGE_NOMATCH);
269 		} else if (*pattern == '\\' && !(flags & FNM_NOESCAPE))
270 			pattern++;
271 		pclen = mbrtowc(&c, pattern, MB_LEN_MAX, patmbs);
272 		if (pclen == (size_t)-1 || pclen == (size_t)-2)
273 			return (RANGE_NOMATCH);
274 		pattern += pclen;
275 
276 		if (flags & FNM_CASEFOLD)
277 			c = towlower(c);
278 
279 		if (*pattern == '-' && *(pattern + 1) != EOS &&
280 		    *(pattern + 1) != ']') {
281 			if (*++pattern == '\\' && !(flags & FNM_NOESCAPE))
282 				if (*pattern != EOS)
283 					pattern++;
284 			pclen = mbrtowc(&c2, pattern, MB_LEN_MAX, patmbs);
285 			if (pclen == (size_t)-1 || pclen == (size_t)-2)
286 				return (RANGE_NOMATCH);
287 			pattern += pclen;
288 			if (c2 == EOS)
289 				return (RANGE_ERROR);
290 
291 			if (flags & FNM_CASEFOLD)
292 				c2 = towlower(c2);
293 
294 			if (table->__collate_load_error ?
295 			    c <= test && test <= c2 :
296 			       __wcollate_range_cmp(c, test) <= 0
297 			    && __wcollate_range_cmp(test, c2) <= 0
298 			   )
299 				ok = 1;
300 		} else if (c == test)
301 			ok = 1;
302 	}
303 
304 	*newp = (char *)pattern;
305 	return (ok == negate ? RANGE_NOMATCH : RANGE_MATCH);
306 }
307