xref: /freebsd/lib/libcompat/4.3/re_comp.c (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
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 
36 /*
37  * Compatibility routines that implement the old re_comp/re_exec interface in
38  * terms of the regcomp/regexec interface.  It's possible that some programs
39  * rely on dark corners of re_comp/re_exec and won't work with this version,
40  * but most programs should be fine.
41  */
42 
43 #include <regex.h>
44 #include <stddef.h>
45 #include <unistd.h>
46 
47 static regex_t re_regexp;
48 static int re_gotexp;
49 static char re_errstr[100];
50 
51 char *
52 re_comp(const char *s)
53 {
54 	int rc;
55 
56 	if (s == NULL || *s == '\0') {
57 		if (!re_gotexp)
58 			return __DECONST(char *,
59 			    "no previous regular expression");
60 		return (NULL);
61 	}
62 
63 	if (re_gotexp) {
64 		regfree(&re_regexp);
65 		re_gotexp = 0;
66 	}
67 
68 	rc = regcomp(&re_regexp, s, REG_EXTENDED);
69 	if (rc == 0) {
70 		re_gotexp = 1;
71 		return (NULL);
72 	}
73 
74 	regerror(rc, &re_regexp, re_errstr, sizeof(re_errstr));
75 	re_errstr[sizeof(re_errstr) - 1] = '\0';
76 	return (re_errstr);
77 }
78 
79 int
80 re_exec(const char *s)
81 {
82 	int rc;
83 
84 	if (!re_gotexp)
85 		return (-1);
86 	rc = regexec(&re_regexp, s, 0, NULL, 0);
87 	return (rc == 0 ? 1 : 0);
88 }
89