xref: /openbsd-src/lib/libc/gen/confstr.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
1 /*-
2  * Copyright (c) 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char rcsid[] = "$OpenBSD: confstr.c,v 1.6 2003/06/11 21:03:10 deraadt Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <sys/param.h>
35 #include <sys/sysctl.h>
36 
37 #include <errno.h>
38 #include <paths.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 
43 size_t
44 confstr(int name, char *buf, size_t len)
45 {
46 	size_t tlen;
47 	int mib[2], sverrno;
48 	char *p;
49 
50 	switch (name) {
51 	case _CS_PATH:
52 		mib[0] = CTL_USER;
53 		mib[1] = USER_CS_PATH;
54 		if (sysctl(mib, 2, NULL, &tlen, NULL, 0) == -1)
55 			return ((size_t) -1);
56 		if (len != 0 && buf != NULL) {
57 			if ((p = malloc(tlen)) == NULL)
58 				return ((size_t) -1);
59 			if (sysctl(mib, 2, p, &tlen, NULL, 0) == -1) {
60 				sverrno = errno;
61 				free(p);
62 				errno = sverrno;
63 				return ((size_t) -1);
64 			}
65 			/*
66 			 * POSIX 1003.2 requires partial return of
67 			 * the string -- that should be *real* useful.
68 			 */
69 			strlcpy(buf, p, len);
70 			free(p);
71 		}
72 		return (tlen + 1);
73 	default:
74 		errno = EINVAL;
75 		return (0);
76 	}
77 	/* NOTREACHED */
78 }
79