xref: /freebsd/lib/libcompat/4.3/re_comp.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * James da Silva at the University of Maryland at College Park.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 __SCCSID("@(#)regex.c	5.1 (Berkeley) 3/29/92");
37 
38 /*
39  * Compatibility routines that implement the old re_comp/re_exec interface in
40  * terms of the regcomp/regexec interface.  It's possible that some programs
41  * rely on dark corners of re_comp/re_exec and won't work with this version,
42  * but most programs should be fine.
43  */
44 
45 #include <regex.h>
46 #include <stddef.h>
47 #include <unistd.h>
48 
49 static regex_t re_regexp;
50 static int re_gotexp;
51 static char re_errstr[100];
52 
53 char *
54 re_comp(const char *s)
55 {
56 	int rc;
57 
58 	if (s == NULL || *s == '\0') {
59 		if (!re_gotexp)
60 			return __DECONST(char *,
61 			    "no previous regular expression");
62 		return (NULL);
63 	}
64 
65 	if (re_gotexp) {
66 		regfree(&re_regexp);
67 		re_gotexp = 0;
68 	}
69 
70 	rc = regcomp(&re_regexp, s, REG_EXTENDED);
71 	if (rc == 0) {
72 		re_gotexp = 1;
73 		return (NULL);
74 	}
75 
76 	regerror(rc, &re_regexp, re_errstr, sizeof(re_errstr));
77 	re_errstr[sizeof(re_errstr) - 1] = '\0';
78 	return (re_errstr);
79 }
80 
81 int
82 re_exec(const char *s)
83 {
84 	int rc;
85 
86 	if (!re_gotexp)
87 		return (-1);
88 	rc = regexec(&re_regexp, s, 0, NULL, 0);
89 	return (rc == 0 ? 1 : 0);
90 }
91