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freebsd/lib/libc/gen/sysconf.c
Mike Smith d4a7e4ca5d Add a trivial mechanism for returning a useful default value if one is 
available and the kernel MIB setting is zero.

Return the result from getpagesize() if the p1003_1b.pagesize MIB
value is zero.

Suggested by:		Joerg Schilling <schilling@fokus.gmd.de>
1998-06-01 20:58:03 +00:00

300 lines
7.9 KiB
C
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/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Sean Eric Fagan of Cygnus Support.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)sysconf.c 8.2 (Berkeley) 3/20/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/_posix.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <sys/resource.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
/*
* sysconf --
* get configurable system variables.
*
* XXX
* POSIX 1003.1 (ISO/IEC 9945-1, 4.8.1.3) states that the variable values
* not change during the lifetime of the calling process. This would seem
* to require that any change to system limits kill all running processes.
* A workaround might be to cache the values when they are first retrieved
* and then simply return the cached value on subsequent calls. This is
* less useful than returning up-to-date values, however.
*/
long
sysconf(name)
int name;
{
struct rlimit rl;
size_t len;
int mib[2], value;
long defaultresult;
len = sizeof(value);
defaultresult = -1;
switch (name) {
/* 1003.1 */
case _SC_ARG_MAX:
mib[0] = CTL_KERN;
mib[1] = KERN_ARGMAX;
break;
case _SC_CHILD_MAX:
return (getrlimit(RLIMIT_NPROC, &rl) ? -1 : rl.rlim_cur);
case _SC_CLK_TCK:
return (CLK_TCK);
case _SC_JOB_CONTROL:
mib[0] = CTL_KERN;
mib[1] = KERN_JOB_CONTROL;
goto yesno;
case _SC_NGROUPS_MAX:
mib[0] = CTL_KERN;
mib[1] = KERN_NGROUPS;
break;
case _SC_OPEN_MAX:
return (getrlimit(RLIMIT_NOFILE, &rl) ? -1 : rl.rlim_cur);
case _SC_STREAM_MAX:
mib[0] = CTL_USER;
mib[1] = USER_STREAM_MAX;
break;
case _SC_TZNAME_MAX:
mib[0] = CTL_USER;
mib[1] = USER_TZNAME_MAX;
break;
case _SC_SAVED_IDS:
mib[0] = CTL_KERN;
mib[1] = KERN_SAVED_IDS;
goto yesno;
case _SC_VERSION:
mib[0] = CTL_KERN;
mib[1] = KERN_POSIX1;
break;
/* 1003.2 */
case _SC_BC_BASE_MAX:
mib[0] = CTL_USER;
mib[1] = USER_BC_BASE_MAX;
break;
case _SC_BC_DIM_MAX:
mib[0] = CTL_USER;
mib[1] = USER_BC_DIM_MAX;
break;
case _SC_BC_SCALE_MAX:
mib[0] = CTL_USER;
mib[1] = USER_BC_SCALE_MAX;
break;
case _SC_BC_STRING_MAX:
mib[0] = CTL_USER;
mib[1] = USER_BC_STRING_MAX;
break;
case _SC_COLL_WEIGHTS_MAX:
mib[0] = CTL_USER;
mib[1] = USER_COLL_WEIGHTS_MAX;
break;
case _SC_EXPR_NEST_MAX:
mib[0] = CTL_USER;
mib[1] = USER_EXPR_NEST_MAX;
break;
case _SC_LINE_MAX:
mib[0] = CTL_USER;
mib[1] = USER_LINE_MAX;
break;
case _SC_RE_DUP_MAX:
mib[0] = CTL_USER;
mib[1] = USER_RE_DUP_MAX;
break;
case _SC_2_VERSION:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_VERSION;
break;
case _SC_2_C_BIND:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_C_BIND;
goto yesno;
case _SC_2_C_DEV:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_C_DEV;
goto yesno;
case _SC_2_CHAR_TERM:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_CHAR_TERM;
goto yesno;
case _SC_2_FORT_DEV:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_FORT_DEV;
goto yesno;
case _SC_2_FORT_RUN:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_FORT_RUN;
goto yesno;
case _SC_2_LOCALEDEF:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_LOCALEDEF;
goto yesno;
case _SC_2_SW_DEV:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_SW_DEV;
goto yesno;
case _SC_2_UPE:
mib[0] = CTL_USER;
mib[1] = USER_POSIX2_UPE;
goto yesno;
#ifdef _P1003_1B_VISIBLE
/* POSIX.1B */
case _SC_ASYNCHRONOUS_IO:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_ASYNCHRONOUS_IO;
goto yesno;
case _SC_MAPPED_FILES:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MAPPED_FILES;
goto yesno;
case _SC_MEMLOCK:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MEMLOCK;
goto yesno;
case _SC_MEMLOCK_RANGE:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MEMLOCK_RANGE;
goto yesno;
case _SC_MEMORY_PROTECTION:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MEMORY_PROTECTION;
goto yesno;
case _SC_MESSAGE_PASSING:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MESSAGE_PASSING;
goto yesno;
case _SC_PRIORITIZED_IO:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_PRIORITIZED_IO;
goto yesno;
case _SC_PRIORITY_SCHEDULING:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_PRIORITY_SCHEDULING;
goto yesno;
case _SC_REALTIME_SIGNALS:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_REALTIME_SIGNALS;
goto yesno;
case _SC_SEMAPHORES:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SEMAPHORES;
goto yesno;
case _SC_FSYNC:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_FSYNC;
goto yesno;
case _SC_SHARED_MEMORY_OBJECTS:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SHARED_MEMORY_OBJECTS;
goto yesno;
case _SC_SYNCHRONIZED_IO:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SYNCHRONIZED_IO;
goto yesno;
case _SC_TIMERS:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_TIMERS;
goto yesno;
case _SC_AIO_LISTIO_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_AIO_LISTIO_MAX;
goto yesno;
case _SC_AIO_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_AIO_MAX;
goto yesno;
case _SC_AIO_PRIO_DELTA_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_AIO_PRIO_DELTA_MAX;
goto yesno;
case _SC_DELAYTIMER_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_DELAYTIMER_MAX;
goto yesno;
case _SC_MQ_OPEN_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_MQ_OPEN_MAX;
goto yesno;
case _SC_PAGESIZE:
defaultresult = getpagesize();
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_PAGESIZE;
goto yesno;
case _SC_RTSIG_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_RTSIG_MAX;
goto yesno;
case _SC_SEM_NSEMS_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SEM_NSEMS_MAX;
goto yesno;
case _SC_SEM_VALUE_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SEM_VALUE_MAX;
goto yesno;
case _SC_SIGQUEUE_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_SIGQUEUE_MAX;
goto yesno;
case _SC_TIMER_MAX:
mib[0] = CTL_P1003_1B;
mib[1] = CTL_P1003_1B_TIMER_MAX;
goto yesno;
#endif /* _P1003_1B_VISIBLE */
yesno: if (sysctl(mib, 2, &value, &len, NULL, 0) == -1)
return (-1);
if (value == 0)
return (defaultresult);
return (value);
break;
default:
errno = EINVAL;
return (-1);
}
return (sysctl(mib, 2, &value, &len, NULL, 0) == -1 ? -1 : value);
}
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