xref: /freebsd/lib/libc/gen/sysctl.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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 
46 extern int __sysctl(const int *name, u_int namelen, void *oldp,
47     size_t *oldlenp, const void *newp, size_t newlen);
48 
49 int
50 sysctl(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