xref: /freebsd/lib/libc/gen/sysctlnametomib.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright 2001 The FreeBSD Project. All Rights Reserved.
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 FREEBSD PROJECT ``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 FREEBSD PROJECT 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/types.h>
31 #include <sys/sysctl.h>
32 #include <string.h>
33 
34 /*
35  * This function uses a presently undocumented interface to the kernel
36  * to walk the tree and get the type so it can print the value.
37  * This interface is under work and consideration, and should probably
38  * be killed with a big axe by the first person who can find the time.
39  * (be aware though, that the proper interface isn't as obvious as it
40  * may seem, there are various conflicting requirements.
41  */
42 int
43 sysctlnametomib(const char *name, int *mibp, size_t *sizep)
44 {
45 	int oid[2];
46 	int error;
47 
48 	oid[0] = CTL_SYSCTL;
49 	oid[1] = CTL_SYSCTL_NAME2OID;
50 
51 	*sizep *= sizeof(int);
52 	error = sysctl(oid, 2, mibp, sizep, name, strlen(name));
53 	*sizep /= sizeof(int);
54 	return (error);
55 }
56