xref: /freebsd/lib/libc/gen/confstr.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)confstr.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/param.h>
39 #include <sys/sysctl.h>
40 
41 #include <errno.h>
42 #include <paths.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45 #include <string.h>
46 
47 size_t
48 confstr(name, buf, len)
49 	int name;
50 	char *buf;
51 	size_t len;
52 {
53 	size_t tlen;
54 	int mib[2], sverrno;
55 	char *p;
56 
57 	switch (name) {
58 	case _CS_PATH:
59 		mib[0] = CTL_USER;
60 		mib[1] = USER_CS_PATH;
61 		if (sysctl(mib, 2, NULL, &tlen, NULL, 0) == -1)
62 			return (-1);
63 		if (len != 0 && buf != NULL) {
64 			if ((p = malloc(tlen)) == NULL)
65 				return (-1);
66 			if (sysctl(mib, 2, p, &tlen, NULL, 0) == -1) {
67 				sverrno = errno;
68 				free(p);
69 				errno = sverrno;
70 				return (-1);
71 			}
72 			/*
73 			 * POSIX 1003.2 requires partial return of
74 			 * the string -- that should be *real* useful.
75 			 */
76 			(void)strncpy(buf, p, len - 1);
77 			buf[len - 1] = '\0';
78 			free(p);
79 		}
80 		return (tlen + 1);
81 	default:
82 		errno = EINVAL;
83 		return (0);
84 	}
85 	/* NOTREACHED */
86 }
87