sysconf.cpp revision 44b53ad6818de344e0b499ad8fdbb21fcb0ff2b6
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <asm/page.h> 30#include <bionic_tls.h> 31#include <ctype.h> 32#include <dirent.h> 33#include <errno.h> 34#include <fcntl.h> 35#include <limits.h> 36#include <stdio.h> // For FOPEN_MAX. 37#include <string.h> 38#include <sys/sysconf.h> 39#include <time.h> 40#include <unistd.h> 41 42/* seems to be the default on Linux, per the GLibc sources and my own digging */ 43 44#define SYSTEM_CLK_TCK 100 45#define SYSTEM_IOV_MAX 1024 46#define SYSTEM_DELAYTIMER_MAX 2147483647 47#define SYSTEM_MQ_OPEN_MAX 8 48#define SYSTEM_MQ_PRIO_MAX 32768 49#define SYSTEM_SEM_NSEMS_MAX 256 50#define SYSTEM_SEM_VALUE_MAX 0x3fffffff /* see bionic/semaphore.c */ 51#define SYSTEM_SIGQUEUE_MAX 32 52#define SYSTEM_TIMER_MAX 32 53#define SYSTEM_LOGIN_NAME_MAX 256 54#define SYSTEM_TTY_NAME_MAX 32 55 56/* the following depends on our implementation */ 57#define SYSTEM_ATEXIT_MAX 65536 /* our implementation is unlimited */ 58#define SYSTEM_THREAD_STACK_MIN 32768 /* lower values may be possible, but be conservative */ 59#define SYSTEM_THREAD_THREADS_MAX 2048 /* really unlimited */ 60 61#define SYSTEM_2_C_BIND _POSIX_VERSION /* Posix C binding version */ 62#define SYSTEM_2_C_VER _POSIX2_C_VERSION 63#define SYSTEM_2_C_DEV -1 /* Posix C development tools unsupported on the device */ 64#define SYSTEM_2_FORT_DEV -1 /* Fortran development unsupported */ 65#define SYSTEM_2_FORT_RUN -1 /* Fortran runtime unsupported */ 66#define SYSTEM_2_SW_DEV -1 /* posix software dev utilities unsupported */ 67#define SYSTEM_2_LOCALEDEF -1 /* localedef() unimplemented */ 68#define SYSTEM_2_UPE -1 /* No UPE for you ! (User Portability Utilities) */ 69#define SYSTEM_2_VERSION -1 /* No posix command-line tools */ 70 71static bool __matches_cpuN(const char* s) { 72 // The %c trick is to ensure that we have the anchored match "^cpu[0-9]+$". 73 unsigned cpu; 74 char dummy; 75 return (sscanf(s, "cpu%u%c", &cpu, &dummy) == 1); 76} 77 78static int __sysconf_nprocessors_conf() { 79 // On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear 80 // from there. This method works on both. 81 DIR* d = opendir("/sys/devices/system/cpu"); 82 if (!d) { 83 return 1; 84 } 85 86 int result = 0; 87 struct dirent* e; 88 while ((e = readdir(d)) != NULL) { 89 if (e->d_type == DT_DIR && __matches_cpuN(e->d_name)) { 90 ++result; 91 } 92 } 93 closedir(d); 94 return result; 95} 96 97static int __sysconf_nprocessors_onln() { 98 FILE* fp = fopen("/proc/stat", "r"); 99 if (fp == NULL) { 100 return 1; 101 } 102 103 int result = 0; 104 char buf[256]; 105 while (fgets(buf, sizeof(buf), fp) != NULL) { 106 // Extract just the first word from the line. 107 // 'cpu0 7976751 1364388 3116842 469770388 8629405 0 49047 0 0 0' 108 char* p = strchr(buf, ' '); 109 if (p != NULL) { 110 *p = 0; 111 } 112 if (__matches_cpuN(buf)) { 113 ++result; 114 } 115 } 116 fclose(fp); 117 return result; 118} 119 120static int __get_meminfo(const char* pattern) { 121 FILE* fp = fopen("/proc/meminfo", "r"); 122 if (fp == NULL) { 123 return -1; 124 } 125 126 int result = -1; 127 char buf[256]; 128 while (fgets(buf, sizeof(buf), fp) != NULL) { 129 long total; 130 if (sscanf(buf, pattern, &total) == 1) { 131 result = (int) (total / (PAGE_SIZE/1024)); 132 break; 133 } 134 } 135 fclose(fp); 136 return result; 137} 138 139static int __sysconf_phys_pages() { 140 return __get_meminfo("MemTotal: %ld kB"); 141} 142 143static int __sysconf_avphys_pages() { 144 return __get_meminfo("MemFree: %ld kB"); 145} 146 147static int __sysconf_monotonic_clock() { 148 timespec t; 149 int rc = clock_getres(CLOCK_MONOTONIC, &t); 150 return (rc == -1) ? -1 : _POSIX_VERSION; 151} 152 153int sysconf(int name) { 154 switch (name) { 155#ifdef _POSIX_ARG_MAX 156 case _SC_ARG_MAX: return _POSIX_ARG_MAX; 157#endif 158#ifdef _POSIX2_BC_BASE_MAX 159 case _SC_BC_BASE_MAX: return _POSIX2_BC_BASE_MAX; 160#endif 161#ifdef _POSIX2_BC_DIM_MAX 162 case _SC_BC_DIM_MAX: return _POSIX2_BC_DIM_MAX; 163#endif 164#ifdef _POSIX2_BC_SCALE_MAX 165 case _SC_BC_SCALE_MAX: return _POSIX2_BC_SCALE_MAX; 166#endif 167#ifdef _POSIX2_BC_STRING_MAX 168 case _SC_BC_STRING_MAX: return _POSIX2_BC_STRING_MAX; 169#endif 170 case _SC_CHILD_MAX: return CHILD_MAX; 171 case _SC_CLK_TCK: return SYSTEM_CLK_TCK; 172#ifdef _POSIX2_COLL_WEIGHTS_MASK 173 case _SC_COLL_WEIGHTS_MAX: return _POSIX2_COLL_WEIGHTS_MASK; 174#endif 175#ifdef _POSIX2_EXPR_NEST_MAX 176 case _SC_EXPR_NEST_MAX: return _POSIX2_EXPR_NEST_MAX; 177#endif 178#ifdef _POSIX2_LINE_MAX 179 case _SC_LINE_MAX: return _POSIX2_LINE_MAX; 180#endif 181 case _SC_NGROUPS_MAX: return NGROUPS_MAX; 182 case _SC_OPEN_MAX: return OPEN_MAX; 183 //case _SC_PASS_MAX: return PASS_MAX; 184 case _SC_2_C_BIND: return SYSTEM_2_C_BIND; 185 case _SC_2_C_DEV: return SYSTEM_2_C_DEV; 186 case _SC_2_C_VERSION: return SYSTEM_2_C_VER; 187 //case _SC_2_CHAR_TERM: return ; 188 case _SC_2_FORT_DEV: return SYSTEM_2_FORT_DEV; 189 case _SC_2_FORT_RUN: return SYSTEM_2_FORT_RUN; 190 case _SC_2_LOCALEDEF: return SYSTEM_2_LOCALEDEF; 191 case _SC_2_SW_DEV: return SYSTEM_2_SW_DEV; 192 case _SC_2_UPE: return SYSTEM_2_UPE; 193 case _SC_2_VERSION: return SYSTEM_2_VERSION; 194#ifdef _POSIX_JOB_CONTROL 195 case _SC_JOB_CONTROL: return _POSIX_JOB_CONTROL; 196#endif 197#ifdef _POSIX_SAVED_IDS 198 case _SC_SAVED_IDS: return _POSIX_SAVED_IDS; 199#endif 200#ifdef _POSIX_VERSION 201 case _SC_VERSION: return _POSIX_VERSION; 202#endif 203 //case _SC_RE_DUP_<AX: return ; 204 case _SC_STREAM_MAX: return FOPEN_MAX; 205 //case _SC_TZNAME_MAX: return ; 206#if _XOPEN_CRYPT 207 case _SC_XOPEN_CRYPT: return _XOPEN_CRYPT; 208#endif 209#ifdef _XOPEN_ENH_I18N 210 case _SC_XOPEN_ENH_I18N: return _XOPEN_ENH_I18N; 211#endif 212#ifdef _XOPEN_SHM 213 case _SC_XOPEN_SHM: return _XOPEN_SHM; 214#endif 215#ifdef _XOPEN_VERSION 216 case _SC_XOPEN_VERSION: return _XOPEN_VERSION; 217#endif 218#ifdef _XOPEN_XCU_VERSION 219 case _SC_XOPEN_XCU_VERSION: return _XOPEN_XCU_VERSION; 220#endif 221#ifdef _XOPEN_REALTIME 222 case _SC_XOPEN_REALTIME: return _XOPEN_REALTIME; 223#endif 224#ifdef _XOPEN_REALTIME_THREADS 225 case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS; 226#endif 227#ifdef _XOPEN_LEGACY 228 case _SC_XOPEN_LEGACY: return _XOPEN_LEGACY; 229#endif 230 case _SC_ATEXIT_MAX: return SYSTEM_ATEXIT_MAX; 231 case _SC_IOV_MAX: return SYSTEM_IOV_MAX; 232 case _SC_PAGESIZE: return PAGE_SIZE; 233 case _SC_PAGE_SIZE: return PAGE_SIZE; 234#ifdef _XOPEN_UNIX 235 case _SC_XOPEN_UNIX: return _XOPEN_UNIX; 236#endif 237 238 // XXX: TODO: XBS5 nonsense 239 240#ifdef AIO_LISTIO_MAX 241 case _SC_AIO_LISTIO_MAX: return AIO_LISTIO_MAX; 242#endif 243#ifdef AIO_MAX 244 case _SC_AIO_MAX: return AIO_MAX; 245#endif 246#ifdef AIO_PRIO_DELTA_MAX 247 case _SC_AIO_PRIO_DELTA_MAX: return AIO_PRIO_DELTA_MAX; 248#endif 249 case _SC_DELAYTIMER_MAX: return SYSTEM_DELAYTIMER_MAX; 250 case _SC_MQ_OPEN_MAX: return SYSTEM_MQ_OPEN_MAX; 251 case _SC_MQ_PRIO_MAX: return SYSTEM_MQ_PRIO_MAX; 252 case _SC_RTSIG_MAX: return RTSIG_MAX; 253 case _SC_SEM_NSEMS_MAX: return SYSTEM_SEM_NSEMS_MAX; 254 case _SC_SEM_VALUE_MAX: return SYSTEM_SEM_VALUE_MAX; 255 case _SC_SIGQUEUE_MAX: return SYSTEM_SIGQUEUE_MAX; 256 case _SC_TIMER_MAX: return SYSTEM_TIMER_MAX; 257#ifdef _POSIX_ASYNCHRONOUS_IO 258 case _SC_ASYNCHRONOUS_IO: return _POSIX_ASYNCHRONOUS_IO; 259#endif 260#ifdef _POSIX_FSYNC 261 case _SC_FSYNC: return _POSIX_FSYNC; 262#endif 263#ifdef _POSIX_MAPPED_FILES 264 case _SC_MAPPED_FILES: return _POSIX_MAPPED_FILES; 265#endif 266#ifdef _POSIX_MEMLOCK 267 case _SC_MEMLOCK: return _POSIX_MEMLOCK; 268#endif 269#ifdef _POSIX_MEMLOCK_RANGE 270 case _SC_MEMLOCK_RANGE: return _POSIX_MEMLOCK_RANGE 271#endif 272#ifdef _POSIX_MEMORY_PROTECTION 273 case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION; 274#endif 275#ifdef _POSIX_MESSAGE_PASSING 276 case _SC_MESSAGE_PASSING: return _POSIX_MESSAGE_PASSING; 277#endif 278#ifdef _POSIX_PRIORITIZED_IO 279 case _SC_PRIORITIZED_IO: return _POSIX_PRIORITIZED_IO; 280#endif 281#ifdef _POSIX_PRIORITY_SCHEDULING 282 case _SC_PRIORITY_SCHEDULING: return _POSIX_PRIORITY_SCHEDULING; 283#endif 284#ifdef _POSIX_REALTIME_SIGNALS 285 case _SC_REALTIME_SIGNALS: return _POSIX_REALTIME_SIGNALS; 286#endif 287#ifdef _POSIX_SEMAPHORES 288 case _SC_SEMAPHORES: return _POSIX_SEMAPHORES; 289#endif 290#ifdef _POSIX_SHARED_MEMORY_OBJECTS 291 case _SC_SHARED_MEMORY_OBJECTS: return _POSIX_SHARED_MEMORY_OBJECTS; 292#endif 293#ifdef _POSIX_SYNCHRONIZED_IO 294 case _SC_SYNCHRONIZED_IO: return _POSIX_SYNCHRONIZED_IO; 295#endif 296#ifdef _POSIX_TIMERS 297 case _SC_TIMERS: return _POSIX_TIMERS; 298#endif 299 300 // GETGR_R_SIZE_MAX ? 301 // GETPW_R_SIZE_MAX ? 302 303 case _SC_LOGIN_NAME_MAX: return SYSTEM_LOGIN_NAME_MAX; 304 305 case _SC_THREAD_DESTRUCTOR_ITERATIONS: 306 return _POSIX_THREAD_DESTRUCTOR_ITERATIONS; 307 308 case _SC_THREAD_KEYS_MAX: 309 return (BIONIC_TLS_SLOTS - TLS_SLOT_FIRST_USER_SLOT); 310 311 case _SC_THREAD_STACK_MIN: return SYSTEM_THREAD_STACK_MIN; 312 case _SC_THREAD_THREADS_MAX: return SYSTEM_THREAD_THREADS_MAX; 313 case _SC_TTY_NAME_MAX: return SYSTEM_TTY_NAME_MAX; 314#ifdef _POSIX_THREADS 315 case _SC_THREADS: return _POSIX_THREADS; 316#endif 317#ifdef _POSIX_THREAD_ATTR_STACKADDR 318 case _SC_THREAD_ATTR_STACKADDR: return _POSIX_THREAD_ATTR_STACKADDR; 319#endif 320#ifdef _POSIX_THREAD_ATTR_STACKSIZE 321 case _SC_THREAD_ATTR_STACKSIZE: return _POSIX_THREAD_ATTR_STACKSIZE; 322#endif 323#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING 324 case _SC_THREAD_PRIORITY_SCHEDULING: return _POSIX_THREAD_PRIORITY_SCHEDULING; 325#endif 326#ifdef _POSIX_THREAD_PRIO_INHERIT 327 case _SC_THREAD_PRIO_INHERIT: return _POSIX_THREAD_PRIO_INHERIT; 328#endif 329#ifdef _POSIX_THREAD_PRIO_PROTECT 330 case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT; 331#endif 332#ifdef _POSIX_THREAD_SAFE_FUNCTIONS 333 case _SC_THREAD_SAFE_FUNCTIONS: return _POSIX_THREAD_SAFE_FUNCTIONS 334#endif 335 336 case _SC_MONOTONIC_CLOCK: return __sysconf_monotonic_clock(); 337 case _SC_NPROCESSORS_CONF: return __sysconf_nprocessors_conf(); 338 case _SC_NPROCESSORS_ONLN: return __sysconf_nprocessors_onln(); 339 case _SC_PHYS_PAGES: return __sysconf_phys_pages(); 340 case _SC_AVPHYS_PAGES: return __sysconf_avphys_pages(); 341 342 default: 343 /* Posix says EINVAL is the only error that shall be returned, 344 * but GLibc uses ENOSYS */ 345 errno = ENOSYS; 346 return -1; 347 } 348} 349