gen/FreeBSD/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  * 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 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/gen/sysconf.c,v 1.20 2002/11/17 08:54:29 dougb Exp $");
  42
  43 #include <sys/param.h>
  44 #include <sys/time.h>
  45 #include <sys/sysctl.h>
  46 #include <sys/resource.h>
  47 #include <sys/socket.h>
  48
  49 #include <errno.h>
  50 #include <limits.h>
  51 #include <paths.h>
  52 #include <pthread.h>            /* we just need the limits */
  53 #include <time.h>
  54 #include <unistd.h>
  55
  56 #include "../stdlib/atexit.h"
  57 #include "../stdtime/tzfile.h"
  58
  59 #define _PATH_ZONEINFO  TZDIR   /* from tzfile.h */
  60
  61 /*
  62  * sysconf --
  63  *      get configurable system variables.
  64  *
  65  * XXX
  66  * POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values
  67  * not change during the lifetime of the calling process.  This would seem
  68  * to require that any change to system limits kill all running processes.
  69  * A workaround might be to cache the values when they are first retrieved
  70  * and then simply return the cached value on subsequent calls.  This is
  71  * less useful than returning up-to-date values, however.
  72  */
  73 long
  74 sysconf(name)
  75         int name;
  76 {
  77         struct rlimit rl;
  78         size_t len;
  79         int mib[2], sverrno, value;
  80         long defaultresult;
  81         const char *path;
  82
  83         len = sizeof(value);
  84         defaultresult = -1;
  85
  86         switch (name) {
  87         case _SC_ARG_MAX:
  88                 mib[0] = CTL_KERN;
  89                 mib[1] = KERN_ARGMAX;
  90                 break;
  91         case _SC_CHILD_MAX:
  92                 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
  93                         return (-1);
  94                 if (rl.rlim_cur == RLIM_INFINITY)
  95                         return (-1);
  96                 if (rl.rlim_cur > LONG_MAX) {
  97                         errno = EOVERFLOW;
  98                         return (-1);
  99                 }
 100                 return ((long)rl.rlim_cur);
 101         case _SC_CLK_TCK:
 102                 return (CLK_TCK);
 103         case _SC_NGROUPS_MAX:
 104                 mib[0] = CTL_KERN;
 105                 mib[1] = KERN_NGROUPS;
 106                 break;
 107         case _SC_OPEN_MAX:
 108         case _SC_STREAM_MAX:    /* assume fds run out before memory does */
 109                 if (getrlimit(RLIMIT_NOFILE, &rl) != 0)
 110                         return (-1);
 111                 if (rl.rlim_cur == RLIM_INFINITY)
 112                         return (-1);
 113                 if (rl.rlim_cur > LONG_MAX) {
 114                         errno = EOVERFLOW;
 115                         return (-1);
 116                 }
 117                 return ((long)rl.rlim_cur);
 118         case _SC_JOB_CONTROL:
 119                 return (_POSIX_JOB_CONTROL);
 120         case _SC_SAVED_IDS:
 121                 /* XXX - must be 1 */
 122                 mib[0] = CTL_KERN;
 123                 mib[1] = KERN_SAVED_IDS;
 124                 goto yesno;
 125         case _SC_VERSION:
 126                 mib[0] = CTL_KERN;
 127                 mib[1] = KERN_POSIX1;
 128                 break;
 129         case _SC_BC_BASE_MAX:
 130                 return (BC_BASE_MAX);
 131         case _SC_BC_DIM_MAX:
 132                 return (BC_DIM_MAX);
 133         case _SC_BC_SCALE_MAX:
 134                 return (BC_SCALE_MAX);
 135         case _SC_BC_STRING_MAX:
 136                 return (BC_STRING_MAX);
 137         case _SC_COLL_WEIGHTS_MAX:
 138                 return (COLL_WEIGHTS_MAX);
 139         case _SC_EXPR_NEST_MAX:
 140                 return (EXPR_NEST_MAX);
 141         case _SC_LINE_MAX:
 142                 return (LINE_MAX);
 143         case _SC_RE_DUP_MAX:
 144                 return (RE_DUP_MAX);
 145         case _SC_2_VERSION:
 146                 /*
 147                  * This is something of a lie, but it would be silly at
 148                  * this point to try to deduce this from the contents
 149                  * of the filesystem.
 150                  */
 151                 return (_POSIX2_VERSION);
 152         case _SC_2_C_BIND:
 153                 return (_POSIX2_C_BIND);
 154         case _SC_2_C_DEV:
 155                 return (_POSIX2_C_DEV);
 156         case _SC_2_CHAR_TERM:
 157                 return (_POSIX2_CHAR_TERM);
 158         case _SC_2_FORT_DEV:
 159                 return (_POSIX2_FORT_DEV);
 160         case _SC_2_FORT_RUN:
 161                 return (_POSIX2_FORT_RUN);
 162         case _SC_2_LOCALEDEF:
 163                 return (_POSIX2_LOCALEDEF);
 164         case _SC_2_SW_DEV:
 165                 return (_POSIX2_SW_DEV);
 166         case _SC_2_UPE:
 167                 return (_POSIX2_UPE);
 168         case _SC_TZNAME_MAX:
 169                 path = _PATH_ZONEINFO;
 170 do_NAME_MAX:
 171                 sverrno = errno;
 172                 errno = 0;
 173                 value = pathconf(path, _PC_NAME_MAX);
 174                 if (value == -1 && errno != 0)
 175                         return (-1);
 176                 errno = sverrno;
 177                 return (value);
 178
 179         case _SC_ASYNCHRONOUS_IO:
 180 #if _POSIX_ASYNCHRONOUS_IO == 0
 181                 mib[0] = CTL_P1003_1B;
 182                 mib[1] = CTL_P1003_1B_ASYNCHRONOUS_IO;
 183                 break;
 184 #else
 185                 return (_POSIX_ASYNCHRONOUS_IO);
 186 #endif
 187         case _SC_MAPPED_FILES:
 188                 return (_POSIX_MAPPED_FILES);
 189         case _SC_MEMLOCK:
 190                 return (_POSIX_MEMLOCK);
 191         case _SC_MEMLOCK_RANGE:
 192                 return (_POSIX_MEMLOCK_RANGE);
 193         case _SC_MEMORY_PROTECTION:
 194                 return (_POSIX_MEMORY_PROTECTION);
 195         case _SC_MESSAGE_PASSING:
 196 #if _POSIX_MESSAGE_PASSING == 0
 197                 mib[0] = CTL_P1003_1B;
 198                 mib[1] = CTL_P1003_1B_MESSAGE_PASSING;
 199                 goto yesno;
 200 #else
 201                 return (_POSIX_MESSAGE_PASSING);
 202 #endif
 203         case _SC_PRIORITIZED_IO:
 204 #if _POSIX_PRIORITIZED_IO == 0
 205                 mib[0] = CTL_P1003_1B;
 206                 mib[1] = CTL_P1003_1B_PRIORITIZED_IO;
 207                 goto yesno;
 208 #else
 209                 return (_POSIX_PRIORITIZED_IO);
 210 #endif
 211         case _SC_PRIORITY_SCHEDULING:
 212 #if _POSIX_PRIORITY_SCHEDULING == 0
 213                 mib[0] = CTL_P1003_1B;
 214                 mib[1] = CTL_P1003_1B_PRIORITY_SCHEDULING;
 215                 goto yesno;
 216 #else
 217                 return (_POSIX_PRIORITY_SCHEDULING);
 218 #endif
 219         case _SC_REALTIME_SIGNALS:
 220 #if _POSIX_REALTIME_SIGNALS == 0
 221                 mib[0] = CTL_P1003_1B;
 222                 mib[1] = CTL_P1003_1B_REALTIME_SIGNALS;
 223                 goto yesno;
 224 #else
 225                 return (_POSIX_REALTIME_SIGNALS);
 226 #endif
 227         case _SC_SEMAPHORES:
 228 #if _POSIX_SEMAPHORES == 0
 229                 mib[0] = CTL_P1003_1B;
 230                 mib[1] = CTL_P1003_1B_SEMAPHORES;
 231                 goto yesno;
 232 #else
 233                 return (_POSIX_SEMAPHORES);
 234 #endif
 235         case _SC_FSYNC:
 236                 return (_POSIX_FSYNC);
 237
 238         case _SC_SHARED_MEMORY_OBJECTS:
 239                 return (_POSIX_SHARED_MEMORY_OBJECTS);
 240         case _SC_SYNCHRONIZED_IO:
 241 #if _POSIX_SYNCHRONIZED_IO == 0
 242                 mib[0] = CTL_P1003_1B;
 243                 mib[1] = CTL_P1003_1B_SYNCHRONIZED_IO;
 244                 goto yesno;
 245 #else
 246                 return (_POSIX_SYNCHRONIZED_IO);
 247 #endif
 248         case _SC_TIMERS:
 249 #if _POSIX_TIMERS == 0
 250                 mib[0] = CTL_P1003_1B;
 251                 mib[1] = CTL_P1003_1B_TIMERS;
 252                 goto yesno;
 253 #else
 254                 return (_POSIX_TIMERS);
 255 #endif
 256         case _SC_AIO_LISTIO_MAX:
 257                 mib[0] = CTL_P1003_1B;
 258                 mib[1] = CTL_P1003_1B_AIO_LISTIO_MAX;
 259                 break;
 260         case _SC_AIO_MAX:
 261                 mib[0] = CTL_P1003_1B;
 262                 mib[1] = CTL_P1003_1B_AIO_MAX;
 263                 break;
 264         case _SC_AIO_PRIO_DELTA_MAX:
 265                 mib[0] = CTL_P1003_1B;
 266                 mib[1] = CTL_P1003_1B_AIO_PRIO_DELTA_MAX;
 267                 break;
 268         case _SC_DELAYTIMER_MAX:
 269                 mib[0] = CTL_P1003_1B;
 270                 mib[1] = CTL_P1003_1B_DELAYTIMER_MAX;
 271                 goto yesno;
 272         case _SC_MQ_OPEN_MAX:
 273                 mib[0] = CTL_P1003_1B;
 274                 mib[1] = CTL_P1003_1B_MQ_OPEN_MAX;
 275                 goto yesno;
 276         case _SC_PAGESIZE:
 277                 defaultresult = getpagesize();
 278                 mib[0] = CTL_P1003_1B;
 279                 mib[1] = CTL_P1003_1B_PAGESIZE;
 280                 goto yesno;
 281         case _SC_RTSIG_MAX:
 282                 mib[0] = CTL_P1003_1B;
 283                 mib[1] = CTL_P1003_1B_RTSIG_MAX;
 284                 goto yesno;
 285         case _SC_SEM_NSEMS_MAX:
 286                 mib[0] = CTL_P1003_1B;
 287                 mib[1] = CTL_P1003_1B_SEM_NSEMS_MAX;
 288                 goto yesno;
 289         case _SC_SEM_VALUE_MAX:
 290                 mib[0] = CTL_P1003_1B;
 291                 mib[1] = CTL_P1003_1B_SEM_VALUE_MAX;
 292                 goto yesno;
 293         case _SC_SIGQUEUE_MAX:
 294                 mib[0] = CTL_P1003_1B;
 295                 mib[1] = CTL_P1003_1B_SIGQUEUE_MAX;
 296                 goto yesno;
 297         case _SC_TIMER_MAX:
 298                 mib[0] = CTL_P1003_1B;
 299                 mib[1] = CTL_P1003_1B_TIMER_MAX;
 300
 301 yesno:          if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
 302                         return (-1);
 303                 if (value == 0)
 304                         return (defaultresult);
 305                 return (value);
 306
 307         case _SC_2_PBS:
 308         case _SC_2_PBS_ACCOUNTING:
 309         case _SC_2_PBS_CHECKPOINT:
 310         case _SC_2_PBS_LOCATE:
 311         case _SC_2_PBS_MESSAGE:
 312         case _SC_2_PBS_TRACK:
 313 #if _POSIX2_PBS == 0
 314 #error "don't know how to determine _SC_2_PBS"
 315                 /*
 316                  * This probably requires digging through the filesystem
 317                  * to see if the appropriate package has been installed.
 318                  * Since we don't currently support this option at all,
 319                  * it's not worth the effort to write the code now.
 320                  * Figuring out which of the sub-options are supported
 321                  * would be even more difficult, so it's probably easier
 322                  * to always say ``no''.
 323                  */
 324 #else
 325                 return (_POSIX2_PBS);
 326 #endif
 327         case _SC_ADVISORY_INFO:
 328 #if _POSIX_ADVISORY_INFO == 0
 329 #error "_POSIX_ADVISORY_INFO"
 330 #else
 331                 return (_POSIX_ADVISORY_INFO);
 332 #endif
 333         case _SC_BARRIERS:
 334 #if _POSIX_BARRIERS == 0
 335 #error "_POSIX_BARRIERS"
 336 #else
 337                 return (_POSIX_BARRIERS);
 338 #endif
 339         case _SC_CLOCK_SELECTION:
 340 #if _POSIX_CLOCK_SELECTION == 0
 341 #error "_POSIX_CLOCK_SELECTION"
 342 #else
 343                 return (_POSIX_CLOCK_SELECTION);
 344 #endif
 345         case _SC_CPUTIME:
 346 #if _POSIX_CPUTIME == 0
 347 #error "_POSIX_CPUTIME"
 348 #else
 349                 return (_POSIX_CPUTIME);
 350 #endif
 351 #ifdef notdef
 352         case _SC_FILE_LOCKING:
 353                 /*
 354                  * XXX - The standard doesn't tell us how to define
 355                  * _POSIX_FILE_LOCKING, so we can't answer this one.
 356                  */
 357 #endif
 358 #if _POSIX_THREAD_SAFE_FUNCTIONS > -1
 359         case _SC_GETGR_R_SIZE_MAX:
 360         case _SC_GETPW_R_SIZE_MAX:
 361 #error "somebody needs to implement this"
 362 #endif
 363         case _SC_HOST_NAME_MAX:
 364                 return (MAXHOSTNAMELEN - 1); /* does not include \0 */
 365         case _SC_LOGIN_NAME_MAX:
 366                 return (MAXLOGNAME);
 367         case _SC_MONOTONIC_CLOCK:
 368 #if _POSIX_MONOTONIC_CLOCK == 0
 369 #error "_POSIX_MONOTONIC_CLOCK"
 370 #else
 371                 return (_POSIX_MONOTONIC_CLOCK);
 372 #endif
 373 #if _POSIX_MESSAGE_PASSING > -1
 374         case _SC_MQ_PRIO_MAX:
 375                 return (MQ_PRIO_MAX);
 376 #endif
 377         case _SC_READER_WRITER_LOCKS:
 378                 return (_POSIX_READER_WRITER_LOCKS);
 379         case _SC_REGEXP:
 380                 return (_POSIX_REGEXP);
 381         case _SC_SHELL:
 382                 return (_POSIX_SHELL);
 383         case _SC_SPAWN:
 384                 return (_POSIX_SPAWN);
 385         case _SC_SPIN_LOCKS:
 386                 return (_POSIX_SPIN_LOCKS);
 387         case _SC_SPORADIC_SERVER:
 388 #if _POSIX_SPORADIC_SERVER == 0
 389 #error "_POSIX_SPORADIC_SERVER"
 390 #else
 391                 return (_POSIX_SPORADIC_SERVER);
 392 #endif
 393         case _SC_THREAD_ATTR_STACKADDR:
 394                 return (_POSIX_THREAD_ATTR_STACKADDR);
 395         case _SC_THREAD_ATTR_STACKSIZE:
 396                 return (_POSIX_THREAD_ATTR_STACKSIZE);
 397         case _SC_THREAD_CPUTIME:
 398                 return (_POSIX_THREAD_CPUTIME);
 399         case _SC_THREAD_DESTRUCTOR_ITERATIONS:
 400                 return (PTHREAD_DESTRUCTOR_ITERATIONS);
 401         case _SC_THREAD_KEYS_MAX:
 402                 return (PTHREAD_KEYS_MAX);
 403         case _SC_THREAD_PRIO_INHERIT:
 404                 return (_POSIX_THREAD_PRIO_INHERIT);
 405         case _SC_THREAD_PRIO_PROTECT:
 406                 return (_POSIX_THREAD_PRIO_PROTECT);
 407         case _SC_THREAD_PRIORITY_SCHEDULING:
 408                 return (_POSIX_THREAD_PRIORITY_SCHEDULING);
 409         case _SC_THREAD_PROCESS_SHARED:
 410                 return (_POSIX_THREAD_PROCESS_SHARED);
 411         case _SC_THREAD_SAFE_FUNCTIONS:
 412                 return (_POSIX_THREAD_SAFE_FUNCTIONS);
 413         case _SC_THREAD_STACK_MIN:
 414                 return (PTHREAD_STACK_MIN);
 415         case _SC_THREAD_THREADS_MAX:
 416                 return (PTHREAD_THREADS_MAX); /* XXX wrong type! */
 417         case _SC_TIMEOUTS:
 418                 return (_POSIX_TIMEOUTS);
 419         case _SC_THREADS:
 420                 return (_POSIX_THREADS);
 421         case _SC_TRACE:
 422 #if _POSIX_TRACE == 0
 423 #error "_POSIX_TRACE"
 424                 /* While you're implementing this, also do the ones below. */
 425 #else
 426                 return (_POSIX_TRACE);
 427 #endif
 428 #if _POSIX_TRACE > -1
 429         case _SC_TRACE_EVENT_FILTER:
 430                 return (_POSIX_TRACE_EVENT_FILTER);
 431         case _SC_TRACE_INHERIT:
 432                 return (_POSIX_TRACE_INHERIT);
 433         case _SC_TRACE_LOG:
 434                 return (_POSIX_TRACE_LOG);
 435 #endif
 436         case _SC_TTY_NAME_MAX:
 437                 path = _PATH_DEV;
 438                 goto do_NAME_MAX;
 439         case _SC_TYPED_MEMORY_OBJECTS:
 440 #if _POSIX_TYPED_MEMORY_OBJECTS == 0
 441 #error "_POSIX_TYPED_MEMORY_OBJECTS"
 442 #else
 443                 return (_POSIX_TYPED_MEMORY_OBJECTS);
 444 #endif
 445         case _SC_V6_ILP32_OFF32:
 446 #if _V6_ILP32_OFF32 == 0
 447                 if (sizeof(int) * CHAR_BIT == 32 &&
 448                     sizeof(int) == sizeof(long) &&
 449                     sizeof(long) == sizeof(void *) &&
 450                     sizeof(void *) == sizeof(off_t))
 451                         return 1;
 452                 else
 453                         return -1;
 454 #else
 455                 return (_V6_ILP32_OFF32);
 456 #endif
 457         case _SC_V6_ILP32_OFFBIG:
 458 #if _V6_ILP32_OFFBIG == 0
 459                 if (sizeof(int) * CHAR_BIT == 32 &&
 460                     sizeof(int) == sizeof(long) &&
 461                     sizeof(long) == sizeof(void *) &&
 462                     sizeof(off_t) * CHAR_BIT >= 64)
 463                         return 1;
 464                 else
 465                         return -1;
 466 #else
 467                 return (_V6_ILP32_OFFBIG);
 468 #endif
 469         case _SC_V6_LP64_OFF64:
 470 #if _V6_LP64_OFF64 == 0
 471                 if (sizeof(int) * CHAR_BIT == 32 &&
 472                     sizeof(long) * CHAR_BIT == 64 &&
 473                     sizeof(long) == sizeof(void *) &&
 474                     sizeof(void *) == sizeof(off_t))
 475                         return 1;
 476                 else
 477                         return -1;
 478 #else
 479                 return (_V6_LP64_OFF64);
 480 #endif
 481         case _SC_V6_LPBIG_OFFBIG:
 482 #if _V6_LPBIG_OFFBIG == 0
 483                 if (sizeof(int) * CHAR_BIT >= 32 &&
 484                     sizeof(long) * CHAR_BIT >= 64 &&
 485                     sizeof(void *) * CHAR_BIT >= 64 &&
 486                     sizeof(off_t) * CHAR_BIT >= 64)
 487                         return 1;
 488                 else
 489                         return -1;
 490 #else
 491                 return (_V6_LPBIG_OFFBIG);
 492 #endif
 493         case _SC_ATEXIT_MAX:
 494                 return (ATEXIT_SIZE);
 495         case _SC_IOV_MAX:
 496                 mib[0] = CTL_KERN;
 497                 mib[1] = KERN_IOV_MAX;
 498                 break;
 499         case _SC_XOPEN_CRYPT:
 500                 return (_XOPEN_CRYPT);
 501         case _SC_XOPEN_ENH_I18N:
 502                 return (_XOPEN_ENH_I18N);
 503         case _SC_XOPEN_LEGACY:
 504                 return (_XOPEN_LEGACY);
 505         case _SC_XOPEN_REALTIME:
 506 #if _XOPEN_REALTIME == 0
 507                 sverrno = errno;
 508                 value = sysconf(_SC_ASYNCHRONOUS_IO) > 0 &&
 509                         sysconf(_SC_MEMLOCK) > 0 &&
 510                         sysconf(_SC_MEMLOCK_RANGE) > 0 &&
 511                         sysconf(_SC_MESSAGE_PASSING) > 0 &&
 512                         sysconf(_SC_PRIORITY_SCHEDULING) > 0 &&
 513                         sysconf(_SC_REALTIME_SIGNALS) > 0 &&
 514                         sysconf(_SC_SEMAPHORES) > 0 &&
 515                         sysconf(_SC_SHARED_MEMORY_OBJECTS) > 0 &&
 516                         sysconf(_SC_SYNCHRONIZED_IO) > 0 &&
 517                         sysconf(_SC_TIMERS) > 0;
 518                 errno = sverrno;
 519                 if (value)
 520                         return (200112L);
 521                 else
 522                         return (-1);
 523 #else
 524                 return (_XOPEN_REALTIME);
 525 #endif
 526         case _SC_XOPEN_REALTIME_THREADS:
 527 #if _XOPEN_REALTIME_THREADS == 0
 528 #error "_XOPEN_REALTIME_THREADS"
 529 #else
 530                 return (_XOPEN_REALTIME_THREADS);
 531 #endif
 532         case _SC_XOPEN_SHM:
 533                 sverrno = errno;
 534                 if (sysctlbyname("kern.ipc.shmmin", &value, &len, NULL,
 535                     0) == -1) {
 536                         errno = sverrno;
 537                         return (-1);
 538                 }
 539                 errno = sverrno;
 540                 return (1);
 541         case _SC_XOPEN_STREAMS:
 542                 return (_XOPEN_STREAMS);
 543         case _SC_XOPEN_UNIX:
 544                 return (_XOPEN_UNIX);
 545 #ifdef _XOPEN_VERSION
 546         case _SC_XOPEN_VERSION:
 547                 return (_XOPEN_VERSION);
 548 #endif
 549 #ifdef _XOPEN_XCU_VERSION
 550         case _SC_XOPEN_XCU_VERSION:
 551                 return (_XOPEN_XCU_VERSION);
 552 #endif
 553         case _SC_SYMLOOP_MAX:
 554                 return (MAXSYMLINKS);
 555         case _SC_RAW_SOCKETS:
 556                 return (_POSIX_RAW_SOCKETS);
 557         case _SC_IPV6:
 558 #if _POSIX_IPV6 == 0
 559                 sverrno = errno;
 560                 value = socket(PF_INET6, SOCK_DGRAM, 0);
 561                 errno = sverrno;
 562                 if (value >= 0) {
 563                         close(value);
 564                         return (200112L);
 565                 } else
 566                         return (0);
 567 #else
 568                 return (_POSIX_IPV6);
 569 #endif
 570
 571         case _SC_NPROCESSORS_CONF:
 572         case _SC_NPROCESSORS_ONLN:
 573                 mib[0] = CTL_HW;
 574                 mib[1] = HW_NCPU;
 575                 break;
 576
 577         default:
 578                 errno = EINVAL;
 579                 return (-1);
 580         }
 581         return (sysctl(mib, 2, &value, &len, NULL, 0) == -1 ? -1 : value);
 582 }