1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__SCCSID("@(#)sysctl.c	8.2 (Berkeley) 1/4/94");
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/sysctl.h>
38
39#include <errno.h>
40#include <limits.h>
41#include <paths.h>
42#include <stdio.h>
43#include <unistd.h>
44#include <string.h>
45
46extern int __sysctl(const int *name, u_int namelen, void *oldp,
47    size_t *oldlenp, const void *newp, size_t newlen);
48
49int
50sysctl(const int *name, u_int namelen, void *oldp, size_t *oldlenp,
51    const void *newp, size_t newlen)
52{
53	int retval;
54	size_t orig_oldlen;
55
56	orig_oldlen = oldlenp != NULL ? *oldlenp : 0;
57	retval = __sysctl(name, namelen, oldp, oldlenp, newp, newlen);
58	/*
59	 * Valid names under CTL_USER except USER_LOCALBASE have a dummy entry
60	 * in the sysctl tree (to support name lookups and enumerations) with
61	 * an empty/zero value, and the true value is supplied by this routine.
62	 * For all such names, __sysctl() is used solely to validate the name.
63	 *
64	 * Return here unless there was a successful lookup for a CTL_USER name.
65	 */
66	if (retval != 0 || name[0] != CTL_USER)
67		return (retval);
68
69	if (namelen != 2) {
70		errno = EINVAL;
71		return (-1);
72	}
73
74	/* Variables under CLT_USER that may be overridden by kernel values */
75	switch (name[1]) {
76	case USER_LOCALBASE:
77		if (oldlenp == NULL || *oldlenp != 1)
78			return (0);
79		if (oldp != NULL) {
80			if (orig_oldlen < sizeof(_PATH_LOCALBASE)) {
81				errno = ENOMEM;
82				return (-1);
83			}
84			memmove(oldp, _PATH_LOCALBASE, sizeof(_PATH_LOCALBASE));
85		}
86		*oldlenp = sizeof(_PATH_LOCALBASE);
87		return (0);
88	}
89
90	/* Variables under CLT_USER whose values are immutably defined below */
91	if (newp != NULL) {
92		errno = EPERM;
93		return (-1);
94	}
95
96	switch (name[1]) {
97	case USER_CS_PATH:
98		if (oldp != NULL && orig_oldlen < sizeof(_PATH_STDPATH)) {
99			errno = ENOMEM;
100			return (-1);
101		}
102		*oldlenp = sizeof(_PATH_STDPATH);
103		if (oldp != NULL)
104			memmove(oldp, _PATH_STDPATH, sizeof(_PATH_STDPATH));
105		return (0);
106	}
107
108	if (oldp != NULL && *oldlenp < sizeof(int)) {
109		errno = ENOMEM;
110		return (-1);
111	}
112	*oldlenp = sizeof(int);
113	if (oldp == NULL)
114		return (0);
115
116	switch (name[1]) {
117	case USER_BC_BASE_MAX:
118		*(int *)oldp = BC_BASE_MAX;
119		return (0);
120	case USER_BC_DIM_MAX:
121		*(int *)oldp = BC_DIM_MAX;
122		return (0);
123	case USER_BC_SCALE_MAX:
124		*(int *)oldp = BC_SCALE_MAX;
125		return (0);
126	case USER_BC_STRING_MAX:
127		*(int *)oldp = BC_STRING_MAX;
128		return (0);
129	case USER_COLL_WEIGHTS_MAX:
130		*(int *)oldp = COLL_WEIGHTS_MAX;
131		return (0);
132	case USER_EXPR_NEST_MAX:
133		*(int *)oldp = EXPR_NEST_MAX;
134		return (0);
135	case USER_LINE_MAX:
136		*(int *)oldp = LINE_MAX;
137		return (0);
138	case USER_RE_DUP_MAX:
139		*(int *)oldp = RE_DUP_MAX;
140		return (0);
141	case USER_POSIX2_VERSION:
142		*(int *)oldp = _POSIX2_VERSION;
143		return (0);
144	case USER_POSIX2_C_BIND:
145#ifdef POSIX2_C_BIND
146		*(int *)oldp = 1;
147#else
148		*(int *)oldp = 0;
149#endif
150		return (0);
151	case USER_POSIX2_C_DEV:
152#ifdef	POSIX2_C_DEV
153		*(int *)oldp = 1;
154#else
155		*(int *)oldp = 0;
156#endif
157		return (0);
158	case USER_POSIX2_CHAR_TERM:
159#ifdef	POSIX2_CHAR_TERM
160		*(int *)oldp = 1;
161#else
162		*(int *)oldp = 0;
163#endif
164		return (0);
165	case USER_POSIX2_FORT_DEV:
166#ifdef	POSIX2_FORT_DEV
167		*(int *)oldp = 1;
168#else
169		*(int *)oldp = 0;
170#endif
171		return (0);
172	case USER_POSIX2_FORT_RUN:
173#ifdef	POSIX2_FORT_RUN
174		*(int *)oldp = 1;
175#else
176		*(int *)oldp = 0;
177#endif
178		return (0);
179	case USER_POSIX2_LOCALEDEF:
180#ifdef	POSIX2_LOCALEDEF
181		*(int *)oldp = 1;
182#else
183		*(int *)oldp = 0;
184#endif
185		return (0);
186	case USER_POSIX2_SW_DEV:
187#ifdef	POSIX2_SW_DEV
188		*(int *)oldp = 1;
189#else
190		*(int *)oldp = 0;
191#endif
192		return (0);
193	case USER_POSIX2_UPE:
194#ifdef	POSIX2_UPE
195		*(int *)oldp = 1;
196#else
197		*(int *)oldp = 0;
198#endif
199		return (0);
200	case USER_STREAM_MAX:
201		*(int *)oldp = FOPEN_MAX;
202		return (0);
203	case USER_TZNAME_MAX:
204		*(int *)oldp = NAME_MAX;
205		return (0);
206	default:
207		errno = EINVAL;
208		return (-1);
209	}
210	/* NOTREACHED */
211}
212