1 /* $NetBSD: os.c,v 1.6 2026/04/08 00:16:15 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * SPDX-License-Identifier: MPL-2.0 7 * 8 * This Source Code Form is subject to the terms of the Mozilla Public 9 * License, v. 2.0. If a copy of the MPL was not distributed with this 10 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 11 * 12 * See the COPYRIGHT file distributed with this work for additional 13 * information regarding copyright ownership. 14 */ 15 16 #include <ctype.h> 17 #include <inttypes.h> 18 #include <sys/stat.h> 19 #include <sys/utsname.h> 20 21 #include <isc/os.h> 22 #include <isc/string.h> 23 #include <isc/types.h> 24 #include <isc/util.h> 25 26 #include "os_p.h" 27 28 static unsigned int isc__os_ncpus = 0; 29 static unsigned long isc__os_cacheline = ISC_OS_CACHELINE_SIZE; 30 static mode_t isc__os_umask = 0; 31 static int kernel_major = -1, kernel_minor = -1, kernel_patch = -1; 32 static char kernel_name[64]; 33 34 #ifdef HAVE_SYSCONF 35 36 #include <unistd.h> 37 38 static long 39 sysconf_ncpus(void) { 40 #if defined(_SC_NPROCESSORS_ONLN) 41 return sysconf(_SC_NPROCESSORS_ONLN); 42 #elif defined(_SC_NPROC_ONLN) 43 return sysconf(_SC_NPROC_ONLN); 44 #else /* if defined(_SC_NPROCESSORS_ONLN) */ 45 return 0; 46 #endif /* if defined(_SC_NPROCESSORS_ONLN) */ 47 } 48 #endif /* HAVE_SYSCONF */ 49 50 #if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) 51 #include <sys/param.h> /* for NetBSD */ 52 #include <sys/sysctl.h> 53 #include <sys/types.h> /* for FreeBSD */ 54 55 static int 56 sysctl_ncpus(void) { 57 int ncpu, result; 58 size_t len; 59 60 len = sizeof(ncpu); 61 result = sysctlbyname("hw.ncpu", &ncpu, &len, 0, 0); 62 if (result != -1) { 63 return ncpu; 64 } 65 return 0; 66 } 67 #endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */ 68 69 #if defined(HAVE_SCHED_GETAFFINITY) 70 71 #if defined(HAVE_SCHED_H) 72 #include <sched.h> 73 #endif 74 75 /* 76 * Administrators may wish to constrain the set of cores that BIND runs 77 * on via the 'taskset' or 'numactl' programs (or equivalent on other 78 * O/S), for example to achieve higher (or more stable) performance by 79 * more closely associating threads with individual NIC rx queues. If 80 * the admin has used taskset, it follows that BIND ought to 81 * automatically use the given number of CPUs rather than the system 82 * wide count. 83 */ 84 static int 85 sched_affinity_ncpus(void) { 86 cpu_set_t cpus; 87 int result; 88 89 result = sched_getaffinity(0, sizeof(cpus), &cpus); 90 if (result != -1) { 91 #ifdef CPU_COUNT 92 return CPU_COUNT(&cpus); 93 #else 94 int i, n = 0; 95 96 for (i = 0; i < CPU_SETSIZE; ++i) { 97 if (CPU_ISSET(i, &cpus)) { 98 ++n; 99 } 100 } 101 return n; 102 #endif 103 } 104 return 0; 105 } 106 #endif 107 108 /* 109 * Affinity detecting variant of sched_affinity_cpus() for FreeBSD 110 */ 111 112 #if defined(HAVE_SYS_CPUSET_H) && defined(HAVE_CPUSET_GETAFFINITY) 113 #include <sys/cpuset.h> 114 #include <sys/param.h> 115 116 static int 117 cpuset_affinity_ncpus(void) { 118 cpuset_t cpus; 119 int result; 120 121 result = cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1, 122 sizeof(cpus), &cpus); 123 if (result != -1) { 124 int i, n = 0; 125 for (i = 0; i < CPU_SETSIZE; ++i) { 126 if (CPU_ISSET(i, &cpus)) { 127 ++n; 128 } 129 } 130 return n; 131 } 132 return 0; 133 } 134 #endif 135 136 static void 137 ncpus_initialize(void) { 138 #if defined(HAVE_SYS_CPUSET_H) && defined(HAVE_CPUSET_GETAFFINITY) 139 if (isc__os_ncpus <= 0) { 140 isc__os_ncpus = cpuset_affinity_ncpus(); 141 } 142 #endif 143 #if defined(HAVE_SCHED_GETAFFINITY) 144 if (isc__os_ncpus <= 0) { 145 isc__os_ncpus = sched_affinity_ncpus(); 146 } 147 #endif 148 #if defined(HAVE_SYSCONF) 149 if (isc__os_ncpus <= 0) { 150 isc__os_ncpus = sysconf_ncpus(); 151 } 152 #endif /* if defined(HAVE_SYSCONF) */ 153 #if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) 154 if (isc__os_ncpus <= 0) { 155 isc__os_ncpus = sysctl_ncpus(); 156 } 157 #endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */ 158 if (isc__os_ncpus <= 0) { 159 isc__os_ncpus = 1; 160 } 161 } 162 163 static void 164 umask_initialize(void) { 165 isc__os_umask = umask(0); 166 (void)umask(isc__os_umask); 167 } 168 169 static void 170 kernel_initialize(void) { 171 struct utsname buffer; 172 173 if (uname(&buffer) == -1) { 174 return; 175 } 176 177 (void)sscanf(buffer.release, "%d.%d.%d", &kernel_major, &kernel_minor, 178 &kernel_patch); 179 (void)strlcpy(kernel_name, buffer.sysname, sizeof(kernel_name)); 180 } 181 182 unsigned int 183 isc_os_ncpus(void) { 184 return isc__os_ncpus; 185 } 186 187 unsigned long 188 isc_os_cacheline(void) { 189 return isc__os_cacheline; 190 } 191 192 mode_t 193 isc_os_umask(void) { 194 return isc__os_umask; 195 } 196 197 void 198 isc_os_kernel(char **name, int *major, int *minor, int *patch) { 199 SET_IF_NOT_NULL(name, kernel_name) 200 SET_IF_NOT_NULL(major, kernel_major); 201 SET_IF_NOT_NULL(minor, kernel_minor); 202 SET_IF_NOT_NULL(patch, kernel_patch); 203 } 204 205 void 206 isc__os_initialize(void) { 207 umask_initialize(); 208 ncpus_initialize(); 209 kernel_initialize(); 210 #if defined(HAVE_SYSCONF) && defined(_SC_LEVEL1_DCACHE_LINESIZE) 211 long s = sysconf(_SC_LEVEL1_DCACHE_LINESIZE); 212 if (s > 0 && (unsigned long)s > isc__os_cacheline) { 213 isc__os_cacheline = s; 214 } 215 #endif 216 } 217 218 void 219 isc__os_shutdown(void) { 220 /* empty, but defined for completeness */; 221 } 222
Indexes created Tue Sep 29 00:26:59 UTC 2026