xref: /freebsd/lib/libc/gen/sysconf.c (revision e627b39baccd1ec9129690167cf5e6d860509655)
1 /*-
2  * Copyright (c) 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Sean Eric Fagan of Cygnus Support.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)sysconf.c	8.2 (Berkeley) 3/20/94";
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include <sys/param.h>
42 #include <sys/time.h>
43 #include <sys/sysctl.h>
44 #include <sys/resource.h>
45 
46 #include <errno.h>
47 #include <time.h>
48 #include <unistd.h>
49 
50 /*
51  * sysconf --
52  *	get configurable system variables.
53  *
54  * XXX
55  * POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values
56  * not change during the lifetime of the calling process.  This would seem
57  * to require that any change to system limits kill all running processes.
58  * A workaround might be to cache the values when they are first retrieved
59  * and then simply return the cached value on subsequent calls.  This is
60  * less useful than returning up-to-date values, however.
61  */
62 long
63 sysconf(name)
64 	int name;
65 {
66 	struct rlimit rl;
67 	size_t len;
68 	int mib[2], value;
69 
70 	len = sizeof(value);
71 
72 	switch (name) {
73 /* 1003.1 */
74 	case _SC_ARG_MAX:
75 		mib[0] = CTL_KERN;
76 		mib[1] = KERN_ARGMAX;
77 		break;
78 	case _SC_CHILD_MAX:
79 		return (getrlimit(RLIMIT_NPROC, &rl) ? -1 : rl.rlim_cur);
80 	case _SC_CLK_TCK:
81 		return (CLK_TCK);
82 	case _SC_JOB_CONTROL:
83 		mib[0] = CTL_KERN;
84 		mib[1] = KERN_JOB_CONTROL;
85 		goto yesno;
86 	case _SC_NGROUPS_MAX:
87 		mib[0] = CTL_KERN;
88 		mib[1] = KERN_NGROUPS;
89 		break;
90 	case _SC_OPEN_MAX:
91 		return (getrlimit(RLIMIT_NOFILE, &rl) ? -1 : rl.rlim_cur);
92 	case _SC_STREAM_MAX:
93 		mib[0] = CTL_USER;
94 		mib[1] = USER_STREAM_MAX;
95 		break;
96 	case _SC_TZNAME_MAX:
97 		mib[0] = CTL_USER;
98 		mib[1] = USER_TZNAME_MAX;
99 		break;
100 	case _SC_SAVED_IDS:
101 		mib[0] = CTL_KERN;
102 		mib[1] = KERN_SAVED_IDS;
103 		goto yesno;
104 	case _SC_VERSION:
105 		mib[0] = CTL_KERN;
106 		mib[1] = KERN_POSIX1;
107 		break;
108 
109 /* 1003.2 */
110 	case _SC_BC_BASE_MAX:
111 		mib[0] = CTL_USER;
112 		mib[1] = USER_BC_BASE_MAX;
113 		break;
114 	case _SC_BC_DIM_MAX:
115 		mib[0] = CTL_USER;
116 		mib[1] = USER_BC_DIM_MAX;
117 		break;
118 	case _SC_BC_SCALE_MAX:
119 		mib[0] = CTL_USER;
120 		mib[1] = USER_BC_SCALE_MAX;
121 		break;
122 	case _SC_BC_STRING_MAX:
123 		mib[0] = CTL_USER;
124 		mib[1] = USER_BC_STRING_MAX;
125 		break;
126 	case _SC_COLL_WEIGHTS_MAX:
127 		mib[0] = CTL_USER;
128 		mib[1] = USER_COLL_WEIGHTS_MAX;
129 		break;
130 	case _SC_EXPR_NEST_MAX:
131 		mib[0] = CTL_USER;
132 		mib[1] = USER_EXPR_NEST_MAX;
133 		break;
134 	case _SC_LINE_MAX:
135 		mib[0] = CTL_USER;
136 		mib[1] = USER_LINE_MAX;
137 		break;
138 	case _SC_RE_DUP_MAX:
139 		mib[0] = CTL_USER;
140 		mib[1] = USER_RE_DUP_MAX;
141 		break;
142 	case _SC_2_VERSION:
143 		mib[0] = CTL_USER;
144 		mib[1] = USER_POSIX2_VERSION;
145 		break;
146 	case _SC_2_C_BIND:
147 		mib[0] = CTL_USER;
148 		mib[1] = USER_POSIX2_C_BIND;
149 		goto yesno;
150 	case _SC_2_C_DEV:
151 		mib[0] = CTL_USER;
152 		mib[1] = USER_POSIX2_C_DEV;
153 		goto yesno;
154 	case _SC_2_CHAR_TERM:
155 		mib[0] = CTL_USER;
156 		mib[1] = USER_POSIX2_CHAR_TERM;
157 		goto yesno;
158 	case _SC_2_FORT_DEV:
159 		mib[0] = CTL_USER;
160 		mib[1] = USER_POSIX2_FORT_DEV;
161 		goto yesno;
162 	case _SC_2_FORT_RUN:
163 		mib[0] = CTL_USER;
164 		mib[1] = USER_POSIX2_FORT_RUN;
165 		goto yesno;
166 	case _SC_2_LOCALEDEF:
167 		mib[0] = CTL_USER;
168 		mib[1] = USER_POSIX2_LOCALEDEF;
169 		goto yesno;
170 	case _SC_2_SW_DEV:
171 		mib[0] = CTL_USER;
172 		mib[1] = USER_POSIX2_SW_DEV;
173 		goto yesno;
174 	case _SC_2_UPE:
175 		mib[0] = CTL_USER;
176 		mib[1] = USER_POSIX2_UPE;
177 yesno:		if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
178 			return (-1);
179 		if (value == 0)
180 			return (-1);
181 		return (value);
182 		break;
183 	default:
184 		errno = EINVAL;
185 		return (-1);
186 	}
187 	return (sysctl(mib, 2, &value, &len, NULL, 0) == -1 ? -1 : value);
188 }
189