xref: /freebsd/lib/libc/gen/sysctlbyname.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3   *
4  * Copyright 2019 Pawel Biernacki, Mysterious Code Ltd.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/sysctl.h>
32 #include <string.h>
33 
34 extern int __sysctlbyname(const char *name, size_t namelen, void *oldp,
35     size_t *oldlenp, const void *newp, size_t newlen);
36 
37 int
38 sysctlbyname(const char *name, void *oldp, size_t *oldlenp,
39     const void *newp, size_t newlen)
40 {
41 	size_t len;
42 	int oid[2];
43 
44 	if (__predict_true(strncmp(name, "user.", 5) != 0)) {
45 		len = strlen(name);
46 		return (__sysctlbyname(name, len, oldp, oldlenp, newp,
47 			newlen));
48 	} else {
49 		len = nitems(oid);
50 		if (sysctlnametomib(name, oid, &len) == -1)
51 			return (-1);
52 		return (sysctl(oid, (u_int)len, oldp, oldlenp, newp,
53 		    newlen));
54 	}
55 }
56