lib/libc/gen/sysconf.c

   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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)sysconf.c   8.2 (Berkeley) 3/20/94";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #include <sys/param.h>
  40 #include <sys/time.h>
  41 #include <sys/sysctl.h>
  42 #include <sys/resource.h>
  43 #include <sys/socket.h>
  44
  45 #include <elf.h>
  46 #include <errno.h>
  47 #include <limits.h>
  48 #include <paths.h>
  49 #include <pthread.h>            /* we just need the limits */
  50 #include <time.h>
  51 #include <unistd.h>
  52
  53 #include "../stdlib/atexit.h"
  54 #include "tzfile.h"             /* from ../../../contrib/tzcode/stdtime */
  55 #include "libc_private.h"
  56
  57 #define _PATH_ZONEINFO  TZDIR   /* from tzfile.h */
  58
  59 /*
  60  * sysconf --
  61  *      get configurable system variables.
  62  *
  63  * XXX
  64  * POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values
  65  * not change during the lifetime of the calling process.  This would seem
  66  * to require that any change to system limits kill all running processes.
  67  * A workaround might be to cache the values when they are first retrieved
  68  * and then simply return the cached value on subsequent calls.  This is
  69  * less useful than returning up-to-date values, however.
  70  */
  71 long
  72 sysconf(name)
  73         int name;
  74 {
  75         struct rlimit rl;
  76         size_t len;
  77         int mib[2], sverrno, value;
  78         long lvalue, defaultresult;
  79         const char *path;
  80
  81         defaultresult = -1;
  82
  83         switch (name) {
  84         case _SC_ARG_MAX:
  85                 mib[0] = CTL_KERN;
  86                 mib[1] = KERN_ARGMAX;
  87                 break;
  88         case _SC_CHILD_MAX:
  89                 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
  90                         return (-1);
  91                 if (rl.rlim_cur == RLIM_INFINITY)
  92                         return (-1);
  93                 if (rl.rlim_cur > LONG_MAX) {
  94                         errno = EOVERFLOW;
  95                         return (-1);
  96                 }
  97                 return ((long)rl.rlim_cur);
  98         case _SC_CLK_TCK:
  99                 return (CLK_TCK);
 100         case _SC_NGROUPS_MAX:
 101                 mib[0] = CTL_KERN;
 102                 mib[1] = KERN_NGROUPS;
 103                 break;
 104         case _SC_OPEN_MAX:
 105                 if (getrlimit(RLIMIT_NOFILE, &rl) != 0)
 106                         return (-1);
 107                 if (rl.rlim_cur == RLIM_INFINITY)
 108                         return (-1);
 109                 if (rl.rlim_cur > LONG_MAX) {
 110                         errno = EOVERFLOW;
 111                         return (-1);
 112                 }
 113                 return ((long)rl.rlim_cur);
 114         case _SC_STREAM_MAX:
 115                 if (getrlimit(RLIMIT_NOFILE, &rl) != 0)
 116                         return (-1);
 117                 if (rl.rlim_cur == RLIM_INFINITY)
 118                         return (-1);
 119                 if (rl.rlim_cur > LONG_MAX) {
 120                         errno = EOVERFLOW;
 121                         return (-1);
 122                 }
 123                 /*
 124                  * struct __sFILE currently has a limitation that
 125                  * file descriptors must fit in a signed short.
 126                  * This doesn't precisely capture the letter of POSIX
 127                  * but approximates the spirit.
 128                  */
 129                 if (rl.rlim_cur > SHRT_MAX)
 130                         return (SHRT_MAX);
 131
 132                 return ((long)rl.rlim_cur);
 133         case _SC_JOB_CONTROL:
 134                 return (_POSIX_JOB_CONTROL);
 135         case _SC_SAVED_IDS:
 136                 /* XXX - must be 1 */
 137                 mib[0] = CTL_KERN;
 138                 mib[1] = KERN_SAVED_IDS;
 139                 goto yesno;
 140         case _SC_VERSION:
 141                 mib[0] = CTL_KERN;
 142                 mib[1] = KERN_POSIX1;
 143                 break;
 144         case _SC_BC_BASE_MAX:
 145                 return (BC_BASE_MAX);
 146         case _SC_BC_DIM_MAX:
 147                 return (BC_DIM_MAX);
 148         case _SC_BC_SCALE_MAX:
 149                 return (BC_SCALE_MAX);
 150         case _SC_BC_STRING_MAX:
 151                 return (BC_STRING_MAX);
 152         case _SC_COLL_WEIGHTS_MAX:
 153                 return (COLL_WEIGHTS_MAX);
 154         case _SC_EXPR_NEST_MAX:
 155                 return (EXPR_NEST_MAX);
 156         case _SC_LINE_MAX:
 157                 return (LINE_MAX);
 158         case _SC_RE_DUP_MAX:
 159                 return (RE_DUP_MAX);
 160         case _SC_2_VERSION:
 161                 /*
 162                  * This is something of a lie, but it would be silly at
 163                  * this point to try to deduce this from the contents
 164                  * of the filesystem.
 165                  */
 166                 return (_POSIX2_VERSION);
 167         case _SC_2_C_BIND:
 168                 return (_POSIX2_C_BIND);
 169         case _SC_2_C_DEV:
 170                 return (_POSIX2_C_DEV);
 171         case _SC_2_CHAR_TERM:
 172                 return (_POSIX2_CHAR_TERM);
 173         case _SC_2_FORT_DEV:
 174                 return (_POSIX2_FORT_DEV);
 175         case _SC_2_FORT_RUN:
 176                 return (_POSIX2_FORT_RUN);
 177         case _SC_2_LOCALEDEF:
 178                 return (_POSIX2_LOCALEDEF);
 179         case _SC_2_SW_DEV:
 180                 return (_POSIX2_SW_DEV);
 181         case _SC_2_UPE:
 182                 return (_POSIX2_UPE);
 183         case _SC_TZNAME_MAX:
 184                 path = _PATH_ZONEINFO;
 185 do_NAME_MAX:
 186                 sverrno = errno;
 187                 errno = 0;
 188                 lvalue = pathconf(path, _PC_NAME_MAX);
 189                 if (lvalue == -1 && errno != 0)
 190                         return (-1);
 191                 errno = sverrno;
 192                 return (lvalue);
 193
 194         case _SC_ASYNCHRONOUS_IO:
 195 #if _POSIX_ASYNCHRONOUS_IO == 0
 196                 mib[0] = CTL_P1003_1B;
 197                 mib[1] = CTL_P1003_1B_ASYNCHRONOUS_IO;
 198                 break;
 199 #else
 200                 return (_POSIX_ASYNCHRONOUS_IO);
 201 #endif
 202         case _SC_MAPPED_FILES:
 203                 return (_POSIX_MAPPED_FILES);
 204         case _SC_MEMLOCK:
 205                 return (_POSIX_MEMLOCK);
 206         case _SC_MEMLOCK_RANGE:
 207                 return (_POSIX_MEMLOCK_RANGE);
 208         case _SC_MEMORY_PROTECTION:
 209                 return (_POSIX_MEMORY_PROTECTION);
 210         case _SC_MESSAGE_PASSING:
 211 #if _POSIX_MESSAGE_PASSING == 0
 212                 mib[0] = CTL_P1003_1B;
 213                 mib[1] = CTL_P1003_1B_MESSAGE_PASSING;
 214                 goto yesno;
 215 #else
 216                 return (_POSIX_MESSAGE_PASSING);
 217 #endif
 218         case _SC_PRIORITIZED_IO:
 219 #if _POSIX_PRIORITIZED_IO == 0
 220                 mib[0] = CTL_P1003_1B;
 221                 mib[1] = CTL_P1003_1B_PRIORITIZED_IO;
 222                 goto yesno;
 223 #else
 224                 return (_POSIX_PRIORITIZED_IO);
 225 #endif
 226         case _SC_PRIORITY_SCHEDULING:
 227 #if _POSIX_PRIORITY_SCHEDULING == 0
 228                 mib[0] = CTL_P1003_1B;
 229                 mib[1] = CTL_P1003_1B_PRIORITY_SCHEDULING;
 230                 goto yesno;
 231 #else
 232                 return (_POSIX_PRIORITY_SCHEDULING);
 233 #endif
 234         case _SC_REALTIME_SIGNALS:
 235 #if _POSIX_REALTIME_SIGNALS == 0
 236                 mib[0] = CTL_P1003_1B;
 237                 mib[1] = CTL_P1003_1B_REALTIME_SIGNALS;
 238                 goto yesno;
 239 #else
 240                 return (_POSIX_REALTIME_SIGNALS);
 241 #endif
 242         case _SC_SEMAPHORES:
 243 #if _POSIX_SEMAPHORES == 0
 244                 mib[0] = CTL_P1003_1B;
 245                 mib[1] = CTL_P1003_1B_SEMAPHORES;
 246                 goto yesno;
 247 #else
 248                 return (_POSIX_SEMAPHORES);
 249 #endif
 250         case _SC_FSYNC:
 251                 return (_POSIX_FSYNC);
 252
 253         case _SC_SHARED_MEMORY_OBJECTS:
 254                 return (_POSIX_SHARED_MEMORY_OBJECTS);
 255         case _SC_SYNCHRONIZED_IO:
 256 #if _POSIX_SYNCHRONIZED_IO == 0
 257                 mib[0] = CTL_P1003_1B;
 258                 mib[1] = CTL_P1003_1B_SYNCHRONIZED_IO;
 259                 goto yesno;
 260 #else
 261                 return (_POSIX_SYNCHRONIZED_IO);
 262 #endif
 263         case _SC_TIMERS:
 264 #if _POSIX_TIMERS == 0
 265                 mib[0] = CTL_P1003_1B;
 266                 mib[1] = CTL_P1003_1B_TIMERS;
 267                 goto yesno;
 268 #else
 269                 return (_POSIX_TIMERS);
 270 #endif
 271         case _SC_AIO_LISTIO_MAX:
 272                 mib[0] = CTL_P1003_1B;
 273                 mib[1] = CTL_P1003_1B_AIO_LISTIO_MAX;
 274                 break;
 275         case _SC_AIO_MAX:
 276                 mib[0] = CTL_P1003_1B;
 277                 mib[1] = CTL_P1003_1B_AIO_MAX;
 278                 break;
 279         case _SC_AIO_PRIO_DELTA_MAX:
 280                 mib[0] = CTL_P1003_1B;
 281                 mib[1] = CTL_P1003_1B_AIO_PRIO_DELTA_MAX;
 282                 break;
 283         case _SC_DELAYTIMER_MAX:
 284                 mib[0] = CTL_P1003_1B;
 285                 mib[1] = CTL_P1003_1B_DELAYTIMER_MAX;
 286                 goto yesno;
 287         case _SC_MQ_OPEN_MAX:
 288                 mib[0] = CTL_P1003_1B;
 289                 mib[1] = CTL_P1003_1B_MQ_OPEN_MAX;
 290                 goto yesno;
 291         case _SC_PAGESIZE:
 292                 defaultresult = getpagesize();
 293                 mib[0] = CTL_P1003_1B;
 294                 mib[1] = CTL_P1003_1B_PAGESIZE;
 295                 goto yesno;
 296         case _SC_RTSIG_MAX:
 297                 mib[0] = CTL_P1003_1B;
 298                 mib[1] = CTL_P1003_1B_RTSIG_MAX;
 299                 goto yesno;
 300         case _SC_SEM_NSEMS_MAX:
 301                 mib[0] = CTL_P1003_1B;
 302                 mib[1] = CTL_P1003_1B_SEM_NSEMS_MAX;
 303                 goto yesno;
 304         case _SC_SEM_VALUE_MAX:
 305                 mib[0] = CTL_P1003_1B;
 306                 mib[1] = CTL_P1003_1B_SEM_VALUE_MAX;
 307                 goto yesno;
 308         case _SC_SIGQUEUE_MAX:
 309                 mib[0] = CTL_P1003_1B;
 310                 mib[1] = CTL_P1003_1B_SIGQUEUE_MAX;
 311                 goto yesno;
 312         case _SC_TIMER_MAX:
 313                 mib[0] = CTL_P1003_1B;
 314                 mib[1] = CTL_P1003_1B_TIMER_MAX;
 315 yesno:
 316                 len = sizeof(value);
 317                 if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
 318                         return (-1);
 319                 if (value == 0)
 320                         return (defaultresult);
 321                 return ((long)value);
 322
 323         case _SC_2_PBS:
 324         case _SC_2_PBS_ACCOUNTING:
 325         case _SC_2_PBS_CHECKPOINT:
 326         case _SC_2_PBS_LOCATE:
 327         case _SC_2_PBS_MESSAGE:
 328         case _SC_2_PBS_TRACK:
 329 #if _POSIX2_PBS == 0
 330 #error "don't know how to determine _SC_2_PBS"
 331                 /*
 332                  * This probably requires digging through the filesystem
 333                  * to see if the appropriate package has been installed.
 334                  * Since we don't currently support this option at all,
 335                  * it's not worth the effort to write the code now.
 336                  * Figuring out which of the sub-options are supported
 337                  * would be even more difficult, so it's probably easier
 338                  * to always say ``no''.
 339                  */
 340 #else
 341                 return (_POSIX2_PBS);
 342 #endif
 343         case _SC_ADVISORY_INFO:
 344 #if _POSIX_ADVISORY_INFO == 0
 345 #error "_POSIX_ADVISORY_INFO"
 346 #else
 347                 return (_POSIX_ADVISORY_INFO);
 348 #endif
 349         case _SC_BARRIERS:
 350 #if _POSIX_BARRIERS == 0
 351 #error "_POSIX_BARRIERS"
 352 #else
 353                 return (_POSIX_BARRIERS);
 354 #endif
 355         case _SC_CLOCK_SELECTION:
 356 #if _POSIX_CLOCK_SELECTION == 0
 357 #error "_POSIX_CLOCK_SELECTION"
 358 #else
 359                 return (_POSIX_CLOCK_SELECTION);
 360 #endif
 361         case _SC_CPUTIME:
 362                 return (_POSIX_CPUTIME);
 363 #ifdef notdef
 364         case _SC_FILE_LOCKING:
 365                 /*
 366                  * XXX - The standard doesn't tell us how to define
 367                  * _POSIX_FILE_LOCKING, so we can't answer this one.
 368                  */
 369 #endif
 370 #if _POSIX_THREAD_SAFE_FUNCTIONS > -1
 371         case _SC_GETGR_R_SIZE_MAX:
 372         case _SC_GETPW_R_SIZE_MAX:
 373 #error "somebody needs to implement this"
 374 #endif
 375         case _SC_HOST_NAME_MAX:
 376                 return (MAXHOSTNAMELEN - 1); /* does not include \0 */
 377         case _SC_LOGIN_NAME_MAX:
 378                 return (MAXLOGNAME);
 379         case _SC_MONOTONIC_CLOCK:
 380 #if _POSIX_MONOTONIC_CLOCK == 0
 381 #error "_POSIX_MONOTONIC_CLOCK"
 382 #else
 383                 return (_POSIX_MONOTONIC_CLOCK);
 384 #endif
 385 #if _POSIX_MESSAGE_PASSING > -1
 386         case _SC_MQ_PRIO_MAX:
 387                 return (MQ_PRIO_MAX);
 388 #endif
 389         case _SC_READER_WRITER_LOCKS:
 390                 return (_POSIX_READER_WRITER_LOCKS);
 391         case _SC_REGEXP:
 392                 return (_POSIX_REGEXP);
 393         case _SC_SHELL:
 394                 return (_POSIX_SHELL);
 395         case _SC_SPAWN:
 396                 return (_POSIX_SPAWN);
 397         case _SC_SPIN_LOCKS:
 398                 return (_POSIX_SPIN_LOCKS);
 399         case _SC_SPORADIC_SERVER:
 400 #if _POSIX_SPORADIC_SERVER == 0
 401 #error "_POSIX_SPORADIC_SERVER"
 402 #else
 403                 return (_POSIX_SPORADIC_SERVER);
 404 #endif
 405         case _SC_THREAD_ATTR_STACKADDR:
 406                 return (_POSIX_THREAD_ATTR_STACKADDR);
 407         case _SC_THREAD_ATTR_STACKSIZE:
 408                 return (_POSIX_THREAD_ATTR_STACKSIZE);
 409         case _SC_THREAD_CPUTIME:
 410                 return (_POSIX_THREAD_CPUTIME);
 411         case _SC_THREAD_DESTRUCTOR_ITERATIONS:
 412                 return (PTHREAD_DESTRUCTOR_ITERATIONS);
 413         case _SC_THREAD_KEYS_MAX:
 414                 return (PTHREAD_KEYS_MAX);
 415         case _SC_THREAD_PRIO_INHERIT:
 416                 return (_POSIX_THREAD_PRIO_INHERIT);
 417         case _SC_THREAD_PRIO_PROTECT:
 418                 return (_POSIX_THREAD_PRIO_PROTECT);
 419         case _SC_THREAD_PRIORITY_SCHEDULING:
 420                 return (_POSIX_THREAD_PRIORITY_SCHEDULING);
 421         case _SC_THREAD_PROCESS_SHARED:
 422                 return (_POSIX_THREAD_PROCESS_SHARED);
 423         case _SC_THREAD_SAFE_FUNCTIONS:
 424                 return (_POSIX_THREAD_SAFE_FUNCTIONS);
 425         case _SC_THREAD_STACK_MIN:
 426                 return (PTHREAD_STACK_MIN);
 427         case _SC_THREAD_THREADS_MAX:
 428                 return (PTHREAD_THREADS_MAX); /* XXX wrong type! */
 429         case _SC_TIMEOUTS:
 430                 return (_POSIX_TIMEOUTS);
 431         case _SC_THREADS:
 432                 return (_POSIX_THREADS);
 433         case _SC_TRACE:
 434 #if _POSIX_TRACE == 0
 435 #error "_POSIX_TRACE"
 436                 /* While you're implementing this, also do the ones below. */
 437 #else
 438                 return (_POSIX_TRACE);
 439 #endif
 440 #if _POSIX_TRACE > -1
 441         case _SC_TRACE_EVENT_FILTER:
 442                 return (_POSIX_TRACE_EVENT_FILTER);
 443         case _SC_TRACE_INHERIT:
 444                 return (_POSIX_TRACE_INHERIT);
 445         case _SC_TRACE_LOG:
 446                 return (_POSIX_TRACE_LOG);
 447 #endif
 448         case _SC_TTY_NAME_MAX:
 449                 path = _PATH_DEV;
 450                 goto do_NAME_MAX;
 451         case _SC_TYPED_MEMORY_OBJECTS:
 452 #if _POSIX_TYPED_MEMORY_OBJECTS == 0
 453 #error "_POSIX_TYPED_MEMORY_OBJECTS"
 454 #else
 455                 return (_POSIX_TYPED_MEMORY_OBJECTS);
 456 #endif
 457         case _SC_V6_ILP32_OFF32:
 458 #if _V6_ILP32_OFF32 == 0
 459                 if (sizeof(int) * CHAR_BIT == 32 &&
 460                     sizeof(int) == sizeof(long) &&
 461                     sizeof(long) == sizeof(void *) &&
 462                     sizeof(void *) == sizeof(off_t))
 463                         return 1;
 464                 else
 465                         return -1;
 466 #else
 467                 return (_V6_ILP32_OFF32);
 468 #endif
 469         case _SC_V6_ILP32_OFFBIG:
 470 #if _V6_ILP32_OFFBIG == 0
 471                 if (sizeof(int) * CHAR_BIT == 32 &&
 472                     sizeof(int) == sizeof(long) &&
 473                     sizeof(long) == sizeof(void *) &&
 474                     sizeof(off_t) * CHAR_BIT >= 64)
 475                         return 1;
 476                 else
 477                         return -1;
 478 #else
 479                 return (_V6_ILP32_OFFBIG);
 480 #endif
 481         case _SC_V6_LP64_OFF64:
 482 #if _V6_LP64_OFF64 == 0
 483                 if (sizeof(int) * CHAR_BIT == 32 &&
 484                     sizeof(long) * CHAR_BIT == 64 &&
 485                     sizeof(long) == sizeof(void *) &&
 486                     sizeof(void *) == sizeof(off_t))
 487                         return 1;
 488                 else
 489                         return -1;
 490 #else
 491                 return (_V6_LP64_OFF64);
 492 #endif
 493         case _SC_V6_LPBIG_OFFBIG:
 494 #if _V6_LPBIG_OFFBIG == 0
 495                 if (sizeof(int) * CHAR_BIT >= 32 &&
 496                     sizeof(long) * CHAR_BIT >= 64 &&
 497                     sizeof(void *) * CHAR_BIT >= 64 &&
 498                     sizeof(off_t) * CHAR_BIT >= 64)
 499                         return 1;
 500                 else
 501                         return -1;
 502 #else
 503                 return (_V6_LPBIG_OFFBIG);
 504 #endif
 505         case _SC_ATEXIT_MAX:
 506                 return (ATEXIT_SIZE);
 507         case _SC_IOV_MAX:
 508                 mib[0] = CTL_KERN;
 509                 mib[1] = KERN_IOV_MAX;
 510                 break;
 511         case _SC_XOPEN_CRYPT:
 512                 return (_XOPEN_CRYPT);
 513         case _SC_XOPEN_ENH_I18N:
 514                 return (_XOPEN_ENH_I18N);
 515         case _SC_XOPEN_LEGACY:
 516                 return (_XOPEN_LEGACY);
 517         case _SC_XOPEN_REALTIME:
 518 #if _XOPEN_REALTIME == 0
 519                 sverrno = errno;
 520                 value = sysconf(_SC_ASYNCHRONOUS_IO) > 0 &&
 521                         sysconf(_SC_MEMLOCK) > 0 &&
 522                         sysconf(_SC_MEMLOCK_RANGE) > 0 &&
 523                         sysconf(_SC_MESSAGE_PASSING) > 0 &&
 524                         sysconf(_SC_PRIORITY_SCHEDULING) > 0 &&
 525                         sysconf(_SC_REALTIME_SIGNALS) > 0 &&
 526                         sysconf(_SC_SEMAPHORES) > 0 &&
 527                         sysconf(_SC_SHARED_MEMORY_OBJECTS) > 0 &&
 528                         sysconf(_SC_SYNCHRONIZED_IO) > 0 &&
 529                         sysconf(_SC_TIMERS) > 0;
 530                 errno = sverrno;
 531                 if (value)
 532                         return (200112L);
 533                 else
 534                         return (-1);
 535 #else
 536                 return (_XOPEN_REALTIME);
 537 #endif
 538         case _SC_XOPEN_REALTIME_THREADS:
 539 #if _XOPEN_REALTIME_THREADS == 0
 540 #error "_XOPEN_REALTIME_THREADS"
 541 #else
 542                 return (_XOPEN_REALTIME_THREADS);
 543 #endif
 544         case _SC_XOPEN_SHM:
 545                 len = sizeof(lvalue);
 546                 sverrno = errno;
 547                 if (sysctlbyname("kern.ipc.shmmin", &lvalue, &len, NULL,
 548                     0) == -1) {
 549                         errno = sverrno;
 550                         return (-1);
 551                 }
 552                 errno = sverrno;
 553                 return (1);
 554         case _SC_XOPEN_STREAMS:
 555                 return (_XOPEN_STREAMS);
 556         case _SC_XOPEN_UNIX:
 557                 return (_XOPEN_UNIX);
 558 #ifdef _XOPEN_VERSION
 559         case _SC_XOPEN_VERSION:
 560                 return (_XOPEN_VERSION);
 561 #endif
 562 #ifdef _XOPEN_XCU_VERSION
 563         case _SC_XOPEN_XCU_VERSION:
 564                 return (_XOPEN_XCU_VERSION);
 565 #endif
 566         case _SC_SYMLOOP_MAX:
 567                 return (MAXSYMLINKS);
 568         case _SC_RAW_SOCKETS:
 569                 return (_POSIX_RAW_SOCKETS);
 570         case _SC_IPV6:
 571 #if _POSIX_IPV6 == 0
 572                 sverrno = errno;
 573                 value = socket(PF_INET6, SOCK_DGRAM, 0);
 574                 errno = sverrno;
 575                 if (value >= 0) {
 576                         close(value);
 577                         return (200112L);
 578                 } else
 579                         return (0);
 580 #else
 581                 return (_POSIX_IPV6);
 582 #endif
 583
 584         case _SC_NPROCESSORS_CONF:
 585         case _SC_NPROCESSORS_ONLN:
 586                 if (_elf_aux_info(AT_NCPUS, &value, sizeof(value)) == 0)
 587                         return ((long)value);
 588                 mib[0] = CTL_HW;
 589                 mib[1] = HW_NCPU;
 590                 break;
 591
 592 #ifdef _SC_PHYS_PAGES
 593         case _SC_PHYS_PAGES:
 594                 len = sizeof(lvalue);
 595                 if (sysctlbyname("hw.availpages", &lvalue, &len, NULL, 0) == -1)
 596                         return (-1);
 597                 return (lvalue);
 598 #endif
 599
 600 #ifdef _SC_CPUSET_SIZE
 601         case _SC_CPUSET_SIZE:
 602                 len = sizeof(value);
 603                 if (sysctlbyname("kern.sched.cpusetsize", &value, &len, NULL,
 604                     0) == -1)
 605                         return (-1);
 606                 return ((long)value);
 607 #endif
 608
 609         default:
 610                 errno = EINVAL;
 611                 return (-1);
 612         }
 613         len = sizeof(value);
 614         if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
 615                 value = -1;
 616         return ((long)value);
 617 }