1 /* $OpenBSD: sysconf.c,v 1.8 2005/08/08 08:05:34 espie Exp $ */ 2 /*- 3 * Copyright (c) 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Sean Eric Fagan of Cygnus Support. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/sem.h> 36 #include <sys/sysctl.h> 37 #include <sys/time.h> 38 #include <sys/resource.h> 39 40 #include <errno.h> 41 #include <unistd.h> 42 43 /* 44 * sysconf -- 45 * get configurable system variables. 46 * 47 * XXX 48 * POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values 49 * not change during the lifetime of the calling process. This would seem 50 * to require that any change to system limits kill all running processes. 51 * A workaround might be to cache the values when they are first retrieved 52 * and then simply return the cached value on subsequent calls. This is 53 * less useful than returning up-to-date values, however. 54 */ 55 long 56 sysconf(int name) 57 { 58 struct rlimit rl; 59 size_t len; 60 int mib[3], value, namelen; 61 62 len = sizeof(value); 63 namelen = 2; 64 65 switch (name) { 66 /* 1003.1 */ 67 case _SC_ARG_MAX: 68 mib[0] = CTL_KERN; 69 mib[1] = KERN_ARGMAX; 70 break; 71 case _SC_CHILD_MAX: 72 return (getrlimit(RLIMIT_NPROC, &rl) ? -1 : rl.rlim_cur); 73 case _SC_CLK_TCK: 74 return (CLK_TCK); 75 case _SC_JOB_CONTROL: 76 mib[0] = CTL_KERN; 77 mib[1] = KERN_JOB_CONTROL; 78 goto yesno; 79 case _SC_NGROUPS_MAX: 80 mib[0] = CTL_KERN; 81 mib[1] = KERN_NGROUPS; 82 break; 83 case _SC_OPEN_MAX: 84 return (getrlimit(RLIMIT_NOFILE, &rl) ? -1 : rl.rlim_cur); 85 case _SC_STREAM_MAX: 86 mib[0] = CTL_USER; 87 mib[1] = USER_STREAM_MAX; 88 break; 89 case _SC_TZNAME_MAX: 90 mib[0] = CTL_USER; 91 mib[1] = USER_TZNAME_MAX; 92 break; 93 case _SC_SAVED_IDS: 94 mib[0] = CTL_KERN; 95 mib[1] = KERN_SAVED_IDS; 96 goto yesno; 97 case _SC_VERSION: 98 mib[0] = CTL_KERN; 99 mib[1] = KERN_POSIX1; 100 break; 101 102 /* 1003.1b */ 103 case _SC_PAGESIZE: 104 mib[0] = CTL_HW; 105 mib[1] = HW_PAGESIZE; 106 break; 107 case _SC_FSYNC: 108 mib[0] = CTL_KERN; 109 mib[1] = KERN_FSYNC; 110 goto yesno; 111 112 /* 1003.2 */ 113 case _SC_BC_BASE_MAX: 114 mib[0] = CTL_USER; 115 mib[1] = USER_BC_BASE_MAX; 116 break; 117 case _SC_BC_DIM_MAX: 118 mib[0] = CTL_USER; 119 mib[1] = USER_BC_DIM_MAX; 120 break; 121 case _SC_BC_SCALE_MAX: 122 mib[0] = CTL_USER; 123 mib[1] = USER_BC_SCALE_MAX; 124 break; 125 case _SC_BC_STRING_MAX: 126 mib[0] = CTL_USER; 127 mib[1] = USER_BC_STRING_MAX; 128 break; 129 case _SC_COLL_WEIGHTS_MAX: 130 mib[0] = CTL_USER; 131 mib[1] = USER_COLL_WEIGHTS_MAX; 132 break; 133 case _SC_EXPR_NEST_MAX: 134 mib[0] = CTL_USER; 135 mib[1] = USER_EXPR_NEST_MAX; 136 break; 137 case _SC_LINE_MAX: 138 mib[0] = CTL_USER; 139 mib[1] = USER_LINE_MAX; 140 break; 141 case _SC_RE_DUP_MAX: 142 mib[0] = CTL_USER; 143 mib[1] = USER_RE_DUP_MAX; 144 break; 145 case _SC_2_VERSION: 146 mib[0] = CTL_USER; 147 mib[1] = USER_POSIX2_VERSION; 148 break; 149 case _SC_2_C_BIND: 150 mib[0] = CTL_USER; 151 mib[1] = USER_POSIX2_C_BIND; 152 goto yesno; 153 case _SC_2_C_DEV: 154 mib[0] = CTL_USER; 155 mib[1] = USER_POSIX2_C_DEV; 156 goto yesno; 157 case _SC_2_CHAR_TERM: 158 mib[0] = CTL_USER; 159 mib[1] = USER_POSIX2_CHAR_TERM; 160 goto yesno; 161 case _SC_2_FORT_DEV: 162 mib[0] = CTL_USER; 163 mib[1] = USER_POSIX2_FORT_DEV; 164 goto yesno; 165 case _SC_2_FORT_RUN: 166 mib[0] = CTL_USER; 167 mib[1] = USER_POSIX2_FORT_RUN; 168 goto yesno; 169 case _SC_2_LOCALEDEF: 170 mib[0] = CTL_USER; 171 mib[1] = USER_POSIX2_LOCALEDEF; 172 goto yesno; 173 case _SC_2_SW_DEV: 174 mib[0] = CTL_USER; 175 mib[1] = USER_POSIX2_SW_DEV; 176 goto yesno; 177 case _SC_2_UPE: 178 mib[0] = CTL_USER; 179 mib[1] = USER_POSIX2_UPE; 180 goto yesno; 181 182 /* XPG 4.2 */ 183 case _SC_XOPEN_SHM: 184 mib[0] = CTL_KERN; 185 mib[1] = KERN_SYSVSHM; 186 187 yesno: if (sysctl(mib, namelen, &value, &len, NULL, 0) == -1) 188 return (-1); 189 if (value == 0) 190 return (-1); 191 return (value); 192 break; 193 case _SC_SEM_NSEMS_MAX: 194 case _SC_SEM_VALUE_MAX: 195 mib[0] = CTL_KERN; 196 mib[1] = KERN_SEMINFO; 197 mib[2] = name = _SC_SEM_NSEMS_MAX ? 198 KERN_SEMINFO_SEMMNS : KERN_SEMINFO_SEMVMX; 199 namelen = 3; 200 break; 201 default: 202 errno = EINVAL; 203 return (-1); 204 } 205 return (sysctl(mib, namelen, &value, &len, NULL, 0) == -1 ? -1 : value); 206 } 207