xref: /dragonfly/lib/libc/gen/sysconf.c (revision 2038fb68)
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  * @(#)sysconf.c	8.2 (Berkeley) 3/20/94
33  * $FreeBSD: src/lib/libc/gen/sysconf.c,v 1.26 2008/02/27 05:56:57 wollman Exp $
34  * $DragonFly: src/lib/libc/gen/sysconf.c,v 1.5 2008/02/21 12:47:54 hasso Exp $
35  */
36 
37 #include <sys/param.h>
38 #include <sys/time.h>
39 #include <sys/sysctl.h>
40 #include <sys/resource.h>
41 #include <sys/socket.h>
42 
43 #include <errno.h>
44 #include <limits.h>
45 #include <paths.h>
46 #include <pthread.h>		/* we just need the limits */
47 #include <time.h>
48 #include <unistd.h>
49 
50 #include "../stdlib/atexit.h"
51 #include "../stdtime/tzfile.h"
52 
53 #define	_PATH_ZONEINFO	TZDIR	/* from tzfile.h */
54 
55 /*
56  * sysconf --
57  *	get configurable system variables.
58  *
59  * XXX
60  * POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values
61  * not change during the lifetime of the calling process.  This would seem
62  * to require that any change to system limits kill all running processes.
63  * A workaround might be to cache the values when they are first retrieved
64  * and then simply return the cached value on subsequent calls.  This is
65  * less useful than returning up-to-date values, however.
66  */
67 long
68 sysconf(int name)
69 {
70 	struct rlimit rl;
71 	size_t len;
72 	int mib[2], sverrno, value;
73 	long lvalue, defaultresult;
74 	const char *path;
75 
76 	defaultresult = -1;
77 
78 	switch (name) {
79 	case _SC_ARG_MAX:
80 		mib[0] = CTL_KERN;
81 		mib[1] = KERN_ARGMAX;
82 		break;
83 	case _SC_CHILD_MAX:
84 		if (getrlimit(RLIMIT_NPROC, &rl) != 0)
85 			return (-1);
86 		if (rl.rlim_cur == RLIM_INFINITY)
87 			return (-1);
88 		if (rl.rlim_cur > LONG_MAX) {
89 			errno = EOVERFLOW;
90 			return (-1);
91 		}
92 		return ((long)rl.rlim_cur);
93 	case _SC_CLK_TCK:
94 		return (CLK_TCK);
95 	case _SC_NGROUPS_MAX:
96 		mib[0] = CTL_KERN;
97 		mib[1] = KERN_NGROUPS;
98 		break;
99 	case _SC_OPEN_MAX:
100 		if (getrlimit(RLIMIT_NOFILE, &rl) != 0)
101 			return (-1);
102 		if (rl.rlim_cur == RLIM_INFINITY)
103 			return (-1);
104 		if (rl.rlim_cur > LONG_MAX) {
105 			errno = EOVERFLOW;
106 			return (-1);
107 		}
108 		return ((long)rl.rlim_cur);
109 	case _SC_STREAM_MAX:
110 		if (getrlimit(RLIMIT_NOFILE, &rl) != 0)
111 			return (-1);
112 		if (rl.rlim_cur == RLIM_INFINITY)
113 			return (-1);
114 		if (rl.rlim_cur > LONG_MAX) {
115 			errno = EOVERFLOW;
116 			return (-1);
117 		}
118 		/*
119 		 * struct __sFILE currently has a limitation that
120 		 * file descriptors must fit in a signed short.
121 		 * This doesn't precisely capture the letter of POSIX
122 		 * but approximates the spirit.
123 		 */
124 		if (rl.rlim_cur > SHRT_MAX)
125 			return (SHRT_MAX);
126 
127 		return ((long)rl.rlim_cur);
128 	case _SC_JOB_CONTROL:
129 		return (_POSIX_JOB_CONTROL);
130 	case _SC_SAVED_IDS:
131 		/* XXX - must be 1 */
132 		mib[0] = CTL_KERN;
133 		mib[1] = KERN_SAVED_IDS;
134 		goto yesno;
135 	case _SC_VERSION:
136 		mib[0] = CTL_KERN;
137 		mib[1] = KERN_POSIX1;
138 		break;
139 	case _SC_BC_BASE_MAX:
140 		return (BC_BASE_MAX);
141 	case _SC_BC_DIM_MAX:
142 		return (BC_DIM_MAX);
143 	case _SC_BC_SCALE_MAX:
144 		return (BC_SCALE_MAX);
145 	case _SC_BC_STRING_MAX:
146 		return (BC_STRING_MAX);
147 	case _SC_COLL_WEIGHTS_MAX:
148 		return (COLL_WEIGHTS_MAX);
149 	case _SC_EXPR_NEST_MAX:
150 		return (EXPR_NEST_MAX);
151 	case _SC_LINE_MAX:
152 		return (LINE_MAX);
153 	case _SC_RE_DUP_MAX:
154 		return (RE_DUP_MAX);
155 	case _SC_2_VERSION:
156 		/*
157 		 * This is something of a lie, but it would be silly at
158 		 * this point to try to deduce this from the contents
159 		 * of the filesystem.
160 		 */
161 		return (_POSIX2_VERSION);
162 	case _SC_2_C_BIND:
163 		return (_POSIX2_C_BIND);
164 	case _SC_2_C_DEV:
165 		return (_POSIX2_C_DEV);
166 	case _SC_2_CHAR_TERM:
167 		return (_POSIX2_CHAR_TERM);
168 	case _SC_2_FORT_DEV:
169 		return (_POSIX2_FORT_DEV);
170 	case _SC_2_FORT_RUN:
171 		return (_POSIX2_FORT_RUN);
172 	case _SC_2_LOCALEDEF:
173 		return (_POSIX2_LOCALEDEF);
174 	case _SC_2_SW_DEV:
175 		return (_POSIX2_SW_DEV);
176 	case _SC_2_UPE:
177 		return (_POSIX2_UPE);
178 	case _SC_TZNAME_MAX:
179 		path = _PATH_ZONEINFO;
180 do_NAME_MAX:
181 		sverrno = errno;
182 		errno = 0;
183 		lvalue = pathconf(path, _PC_NAME_MAX);
184 		if (lvalue == -1 && errno != 0)
185 			return (-1);
186 		errno = sverrno;
187 		return (lvalue);
188 
189 	case _SC_ASYNCHRONOUS_IO:
190 #if _POSIX_ASYNCHRONOUS_IO == 0
191 		mib[0] = CTL_P1003_1B;
192 		mib[1] = CTL_P1003_1B_ASYNCHRONOUS_IO;
193 		break;
194 #else
195 		return (_POSIX_ASYNCHRONOUS_IO);
196 #endif
197 	case _SC_MAPPED_FILES:
198 		return (_POSIX_MAPPED_FILES);
199 	case _SC_MEMLOCK:
200 		return (_POSIX_MEMLOCK);
201 	case _SC_MEMLOCK_RANGE:
202 		return (_POSIX_MEMLOCK_RANGE);
203 	case _SC_MEMORY_PROTECTION:
204 		return (_POSIX_MEMORY_PROTECTION);
205 	case _SC_MESSAGE_PASSING:
206 #if _POSIX_MESSAGE_PASSING == 0
207 		mib[0] = CTL_P1003_1B;
208 		mib[1] = CTL_P1003_1B_MESSAGE_PASSING;
209 		goto yesno;
210 #else
211 		return (_POSIX_MESSAGE_PASSING);
212 #endif
213 	case _SC_PRIORITIZED_IO:
214 #if _POSIX_PRIORITIZED_IO == 0
215 		mib[0] = CTL_P1003_1B;
216 		mib[1] = CTL_P1003_1B_PRIORITIZED_IO;
217 		goto yesno;
218 #else
219 		return (_POSIX_PRIORITIZED_IO);
220 #endif
221 	case _SC_PRIORITY_SCHEDULING:
222 #if _POSIX_PRIORITY_SCHEDULING == 0
223 		mib[0] = CTL_P1003_1B;
224 		mib[1] = CTL_P1003_1B_PRIORITY_SCHEDULING;
225 		goto yesno;
226 #else
227 		return (_POSIX_PRIORITY_SCHEDULING);
228 #endif
229 	case _SC_REALTIME_SIGNALS:
230 #if _POSIX_REALTIME_SIGNALS == 0
231 		mib[0] = CTL_P1003_1B;
232 		mib[1] = CTL_P1003_1B_REALTIME_SIGNALS;
233 		goto yesno;
234 #else
235 		return (_POSIX_REALTIME_SIGNALS);
236 #endif
237 	case _SC_SEMAPHORES:
238 #if _POSIX_SEMAPHORES == 0
239 		mib[0] = CTL_P1003_1B;
240 		mib[1] = CTL_P1003_1B_SEMAPHORES;
241 		goto yesno;
242 #else
243 		return (_POSIX_SEMAPHORES);
244 #endif
245 	case _SC_FSYNC:
246 		return (_POSIX_FSYNC);
247 
248 	case _SC_SHARED_MEMORY_OBJECTS:
249 		return (_POSIX_SHARED_MEMORY_OBJECTS);
250 	case _SC_SYNCHRONIZED_IO:
251 #if _POSIX_SYNCHRONIZED_IO == 0
252 		mib[0] = CTL_P1003_1B;
253 		mib[1] = CTL_P1003_1B_SYNCHRONIZED_IO;
254 		goto yesno;
255 #else
256 		return (_POSIX_SYNCHRONIZED_IO);
257 #endif
258 	case _SC_TIMERS:
259 #if _POSIX_TIMERS == 0
260 		mib[0] = CTL_P1003_1B;
261 		mib[1] = CTL_P1003_1B_TIMERS;
262 		goto yesno;
263 #else
264 		return (_POSIX_TIMERS);
265 #endif
266 	case _SC_AIO_LISTIO_MAX:
267 		mib[0] = CTL_P1003_1B;
268 		mib[1] = CTL_P1003_1B_AIO_LISTIO_MAX;
269 		break;
270 	case _SC_AIO_MAX:
271 		mib[0] = CTL_P1003_1B;
272 		mib[1] = CTL_P1003_1B_AIO_MAX;
273 		break;
274 	case _SC_AIO_PRIO_DELTA_MAX:
275 		mib[0] = CTL_P1003_1B;
276 		mib[1] = CTL_P1003_1B_AIO_PRIO_DELTA_MAX;
277 		break;
278 	case _SC_DELAYTIMER_MAX:
279 		mib[0] = CTL_P1003_1B;
280 		mib[1] = CTL_P1003_1B_DELAYTIMER_MAX;
281 		goto yesno;
282 	case _SC_MQ_OPEN_MAX:
283 		mib[0] = CTL_P1003_1B;
284 		mib[1] = CTL_P1003_1B_MQ_OPEN_MAX;
285 		goto yesno;
286 	case _SC_PAGESIZE:
287 		defaultresult = getpagesize();
288 		mib[0] = CTL_P1003_1B;
289 		mib[1] = CTL_P1003_1B_PAGESIZE;
290 		goto yesno;
291 	case _SC_RTSIG_MAX:
292 		mib[0] = CTL_P1003_1B;
293 		mib[1] = CTL_P1003_1B_RTSIG_MAX;
294 		goto yesno;
295 	case _SC_SEM_NSEMS_MAX:
296 		mib[0] = CTL_P1003_1B;
297 		mib[1] = CTL_P1003_1B_SEM_NSEMS_MAX;
298 		goto yesno;
299 	case _SC_SEM_VALUE_MAX:
300 		mib[0] = CTL_P1003_1B;
301 		mib[1] = CTL_P1003_1B_SEM_VALUE_MAX;
302 		goto yesno;
303 	case _SC_SIGQUEUE_MAX:
304 		mib[0] = CTL_P1003_1B;
305 		mib[1] = CTL_P1003_1B_SIGQUEUE_MAX;
306 		goto yesno;
307 	case _SC_TIMER_MAX:
308 		mib[0] = CTL_P1003_1B;
309 		mib[1] = CTL_P1003_1B_TIMER_MAX;
310 yesno:
311 		len = sizeof(value);
312 		if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
313 			return (-1);
314 		if (value == 0)
315 			return (defaultresult);
316 		return ((long)value);
317 
318 	case _SC_2_PBS:
319 	case _SC_2_PBS_ACCOUNTING:
320 	case _SC_2_PBS_CHECKPOINT:
321 	case _SC_2_PBS_LOCATE:
322 	case _SC_2_PBS_MESSAGE:
323 	case _SC_2_PBS_TRACK:
324 #if _POSIX2_PBS == 0
325 #error "don't know how to determine _SC_2_PBS"
326 		/*
327 		 * This probably requires digging through the filesystem
328 		 * to see if the appropriate package has been installed.
329 		 * Since we don't currently support this option at all,
330 		 * it's not worth the effort to write the code now.
331 		 * Figuring out which of the sub-options are supported
332 		 * would be even more difficult, so it's probably easier
333 		 * to always say ``no''.
334 		 */
335 #else
336 		return (_POSIX2_PBS);
337 #endif
338 	case _SC_ADVISORY_INFO:
339 #if _POSIX_ADVISORY_INFO == 0
340 #error "_POSIX_ADVISORY_INFO"
341 #else
342 		return (_POSIX_ADVISORY_INFO);
343 #endif
344 	case _SC_BARRIERS:
345 #if _POSIX_BARRIERS == 0
346 #error "_POSIX_BARRIERS"
347 #else
348 		return (_POSIX_BARRIERS);
349 #endif
350 	case _SC_CLOCK_SELECTION:
351 #if _POSIX_CLOCK_SELECTION == 0
352 #error "_POSIX_CLOCK_SELECTION"
353 #else
354 		return (_POSIX_CLOCK_SELECTION);
355 #endif
356 	case _SC_CPUTIME:
357 #if _POSIX_CPUTIME == 0
358 #error "_POSIX_CPUTIME"
359 #else
360 		return (_POSIX_CPUTIME);
361 #endif
362 #ifdef notdef
363 	case _SC_FILE_LOCKING:
364 		/*
365 		 * XXX - The standard doesn't tell us how to define
366 		 * _POSIX_FILE_LOCKING, so we can't answer this one.
367 		 */
368 #endif
369 #if _POSIX_THREAD_SAFE_FUNCTIONS > -1
370 	case _SC_GETGR_R_SIZE_MAX:
371 	case _SC_GETPW_R_SIZE_MAX:
372 #error "somebody needs to implement this"
373 #endif
374 	case _SC_HOST_NAME_MAX:
375 		return (MAXHOSTNAMELEN - 1); /* does not include \0 */
376 	case _SC_LOGIN_NAME_MAX:
377 		return (MAXLOGNAME);
378 	case _SC_MONOTONIC_CLOCK:
379 #if _POSIX_MONOTONIC_CLOCK == 0
380 #error "_POSIX_MONOTONIC_CLOCK"
381 #else
382 		return (_POSIX_MONOTONIC_CLOCK);
383 #endif
384 #if _POSIX_MESSAGE_PASSING > -1
385 	case _SC_MQ_PRIO_MAX:
386 		return (MQ_PRIO_MAX);
387 #endif
388 	case _SC_READER_WRITER_LOCKS:
389 		return (_POSIX_READER_WRITER_LOCKS);
390 	case _SC_REGEXP:
391 		return (_POSIX_REGEXP);
392 	case _SC_SHELL:
393 		return (_POSIX_SHELL);
394 	case _SC_SPAWN:
395 		return (_POSIX_SPAWN);
396 	case _SC_SPIN_LOCKS:
397 		return (_POSIX_SPIN_LOCKS);
398 	case _SC_SPORADIC_SERVER:
399 #if _POSIX_SPORADIC_SERVER == 0
400 #error "_POSIX_SPORADIC_SERVER"
401 #else
402 		return (_POSIX_SPORADIC_SERVER);
403 #endif
404 	case _SC_THREAD_ATTR_STACKADDR:
405 		return (_POSIX_THREAD_ATTR_STACKADDR);
406 	case _SC_THREAD_ATTR_STACKSIZE:
407 		return (_POSIX_THREAD_ATTR_STACKSIZE);
408 	case _SC_THREAD_CPUTIME:
409 		return (_POSIX_THREAD_CPUTIME);
410 	case _SC_THREAD_DESTRUCTOR_ITERATIONS:
411 		return (PTHREAD_DESTRUCTOR_ITERATIONS);
412 	case _SC_THREAD_KEYS_MAX:
413 		return (PTHREAD_KEYS_MAX);
414 	case _SC_THREAD_PRIO_INHERIT:
415 		return (_POSIX_THREAD_PRIO_INHERIT);
416 	case _SC_THREAD_PRIO_PROTECT:
417 		return (_POSIX_THREAD_PRIO_PROTECT);
418 	case _SC_THREAD_PRIORITY_SCHEDULING:
419 		return (_POSIX_THREAD_PRIORITY_SCHEDULING);
420 	case _SC_THREAD_PROCESS_SHARED:
421 		return (_POSIX_THREAD_PROCESS_SHARED);
422 	case _SC_THREAD_SAFE_FUNCTIONS:
423 		return (_POSIX_THREAD_SAFE_FUNCTIONS);
424 	case _SC_THREAD_STACK_MIN:
425 		return (PTHREAD_STACK_MIN);
426 	case _SC_THREAD_THREADS_MAX:
427 		return (PTHREAD_THREADS_MAX); /* XXX wrong type! */
428 	case _SC_TIMEOUTS:
429 		return (_POSIX_TIMEOUTS);
430 	case _SC_THREADS:
431 		return (_POSIX_THREADS);
432 	case _SC_TRACE:
433 #if _POSIX_TRACE == 0
434 #error "_POSIX_TRACE"
435 		/* While you're implementing this, also do the ones below. */
436 #else
437 		return (_POSIX_TRACE);
438 #endif
439 #if _POSIX_TRACE > -1
440 	case _SC_TRACE_EVENT_FILTER:
441 		return (_POSIX_TRACE_EVENT_FILTER);
442 	case _SC_TRACE_INHERIT:
443 		return (_POSIX_TRACE_INHERIT);
444 	case _SC_TRACE_LOG:
445 		return (_POSIX_TRACE_LOG);
446 #endif
447 	case _SC_TTY_NAME_MAX:
448 		path = _PATH_DEV;
449 		goto do_NAME_MAX;
450 	case _SC_TYPED_MEMORY_OBJECTS:
451 #if _POSIX_TYPED_MEMORY_OBJECTS == 0
452 #error "_POSIX_TYPED_MEMORY_OBJECTS"
453 #else
454 		return (_POSIX_TYPED_MEMORY_OBJECTS);
455 #endif
456 	case _SC_V6_ILP32_OFF32:
457 #if _V6_ILP32_OFF32 == 0
458 		if (sizeof(int) * CHAR_BIT == 32 &&
459 		    sizeof(int) == sizeof(long) &&
460 		    sizeof(long) == sizeof(void *) &&
461 		    sizeof(void *) == sizeof(off_t))
462 			return 1;
463 		else
464 			return -1;
465 #else
466 		return (_V6_ILP32_OFF32);
467 #endif
468 	case _SC_V6_ILP32_OFFBIG:
469 #if _V6_ILP32_OFFBIG == 0
470 		if (sizeof(int) * CHAR_BIT == 32 &&
471 		    sizeof(int) == sizeof(long) &&
472 		    sizeof(long) == sizeof(void *) &&
473 		    sizeof(off_t) * CHAR_BIT >= 64)
474 			return 1;
475 		else
476 			return -1;
477 #else
478 		return (_V6_ILP32_OFFBIG);
479 #endif
480 	case _SC_V6_LP64_OFF64:
481 #if _V6_LP64_OFF64 == 0
482 		if (sizeof(int) * CHAR_BIT == 32 &&
483 		    sizeof(long) * CHAR_BIT == 64 &&
484 		    sizeof(long) == sizeof(void *) &&
485 		    sizeof(void *) == sizeof(off_t))
486 			return 1;
487 		else
488 			return -1;
489 #else
490 		return (_V6_LP64_OFF64);
491 #endif
492 	case _SC_V6_LPBIG_OFFBIG:
493 #if _V6_LPBIG_OFFBIG == 0
494 		if (sizeof(int) * CHAR_BIT >= 32 &&
495 		    sizeof(long) * CHAR_BIT >= 64 &&
496 		    sizeof(void *) * CHAR_BIT >= 64 &&
497 		    sizeof(off_t) * CHAR_BIT >= 64)
498 			return 1;
499 		else
500 			return -1;
501 #else
502 		return (_V6_LPBIG_OFFBIG);
503 #endif
504 	case _SC_ATEXIT_MAX:
505 		return (ATEXIT_SIZE);
506 	case _SC_IOV_MAX:
507 		mib[0] = CTL_KERN;
508 		mib[1] = KERN_IOV_MAX;
509 		break;
510 	case _SC_XOPEN_CRYPT:
511 		return (_XOPEN_CRYPT);
512 	case _SC_XOPEN_ENH_I18N:
513 		return (_XOPEN_ENH_I18N);
514 	case _SC_XOPEN_LEGACY:
515 		return (_XOPEN_LEGACY);
516 	case _SC_XOPEN_REALTIME:
517 #if _XOPEN_REALTIME == 0
518 		sverrno = errno;
519 		value = sysconf(_SC_ASYNCHRONOUS_IO) > 0 &&
520 			sysconf(_SC_MEMLOCK) > 0 &&
521 			sysconf(_SC_MEMLOCK_RANGE) > 0 &&
522 			sysconf(_SC_MESSAGE_PASSING) > 0 &&
523 			sysconf(_SC_PRIORITY_SCHEDULING) > 0 &&
524 			sysconf(_SC_REALTIME_SIGNALS) > 0 &&
525 			sysconf(_SC_SEMAPHORES) > 0 &&
526 			sysconf(_SC_SHARED_MEMORY_OBJECTS) > 0 &&
527 			sysconf(_SC_SYNCHRONIZED_IO) > 0 &&
528 			sysconf(_SC_TIMERS) > 0;
529 		errno = sverrno;
530 		if (value)
531 			return (200112L);
532 		else
533 			return (-1);
534 #else
535 		return (_XOPEN_REALTIME);
536 #endif
537 	case _SC_XOPEN_REALTIME_THREADS:
538 #if _XOPEN_REALTIME_THREADS == 0
539 #error "_XOPEN_REALTIME_THREADS"
540 #else
541 		return (_XOPEN_REALTIME_THREADS);
542 #endif
543 	case _SC_XOPEN_SHM:
544 		len = sizeof(lvalue);
545 		sverrno = errno;
546 		if (sysctlbyname("kern.ipc.shmmin", &lvalue, &len, NULL,
547 		    0) == -1) {
548 			errno = sverrno;
549 			return (-1);
550 		}
551 		errno = sverrno;
552 		return (1);
553 	case _SC_XOPEN_STREAMS:
554 		return (_XOPEN_STREAMS);
555 	case _SC_XOPEN_UNIX:
556 		return (_XOPEN_UNIX);
557 #ifdef _XOPEN_VERSION
558 	case _SC_XOPEN_VERSION:
559 		return (_XOPEN_VERSION);
560 #endif
561 #ifdef _XOPEN_XCU_VERSION
562 	case _SC_XOPEN_XCU_VERSION:
563 		return (_XOPEN_XCU_VERSION);
564 #endif
565 	case _SC_SYMLOOP_MAX:
566 		return (MAXSYMLINKS);
567 	case _SC_RAW_SOCKETS:
568 		return (_POSIX_RAW_SOCKETS);
569 	case _SC_IPV6:
570 #if _POSIX_IPV6 == 0
571 		sverrno = errno;
572 		value = socket(PF_INET6, SOCK_DGRAM, 0);
573 		errno = sverrno;
574 		if (value >= 0) {
575 			close(value);
576 			return (200112L);
577 		} else
578 			return (0);
579 #else
580 		return (_POSIX_IPV6);
581 #endif
582 
583 	case _SC_NPROCESSORS_CONF:
584 	case _SC_NPROCESSORS_ONLN:
585 		mib[0] = CTL_HW;
586 		mib[1] = HW_NCPU;
587 		break;
588 
589 #ifdef _SC_PHYS_PAGES
590 	case _SC_PHYS_PAGES:
591 		len = sizeof(lvalue);
592 		if (sysctlbyname("hw.availpages", &lvalue, &len, NULL, 0) == -1)
593 			return (-1);
594 		return (lvalue);
595 #endif
596 
597 	default:
598 		errno = EINVAL;
599 		return (-1);
600 	}
601 	len = sizeof(value);
602 	if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
603 		value = -1;
604 	return ((long)value);
605 }
606