/*      $NetBSD: sysconf.c,v 1.45 2024/12/22 23:17:26 riastradh Exp $   */

/*-
 * 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. 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)sysconf.c   8.2 (Berkeley) 3/20/94";
#else
__RCSID("$NetBSD: sysconf.c,v 1.45 2024/12/22 23:17:26 riastradh Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <uvm/uvm_extern.h>

#include <errno.h>
#include <limits.h>
#include <time.h>
#include <unistd.h>
#include <paths.h>
#include <pwd.h>

#ifdef __weak_alias
__weak_alias(sysconf,__sysconf)
#endif

/*
 * 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(int name)
{
        struct rlimit rl;
        size_t len;
        uint64_t mem;
        int mib[CTL_MAXNAME], value;
        unsigned int mib_len;
        struct clockinfo tmpclock;
        struct uvmexp_sysctl uvmexp;
        static int clk_tck;

        len = sizeof(value);

        /* Default length of the MIB */
        mib_len = 2;

        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 : (long)rl.rlim_cur);
        case _O_SC_CLK_TCK:
                /*
                 * For applications compiled when CLK_TCK was a compile-time
                 * constant.
                 */
                return 100;
        case _SC_CLK_TCK:
                /*
                 * Has to be handled specially because it returns a
                 * struct clockinfo instead of an integer. Also, since
                 * this might be called often by some things that
                 * don't grok CLK_TCK can be a macro expanding to a
                 * function, cache the value.
                 */
                if (clk_tck == 0) {
                        mib[0] = CTL_KERN;
                        mib[1] = KERN_CLOCKRATE;
                        len = sizeof(struct clockinfo);
                        clk_tck = sysctl(mib, 2, &tmpclock, &len, NULL, 0)
                            == -1 ? -1 : tmpclock.hz;
                }
                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
                    : (long)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;

/* 1003.1b */
        case _SC_PAGESIZE:
                return _getpagesize();
        case _SC_FSYNC:
                mib[0] = CTL_KERN;
                mib[1] = KERN_FSYNC;
                goto yesno;
        case _SC_SYNCHRONIZED_IO:
                mib[0] = CTL_KERN;
                mib[1] = KERN_SYNCHRONIZED_IO;
                goto yesno;
        case _SC_MAPPED_FILES:
                mib[0] = CTL_KERN;
                mib[1] = KERN_MAPPED_FILES;
                goto yesno;
        case _SC_MEMLOCK:
                mib[0] = CTL_KERN;
                mib[1] = KERN_MEMLOCK;
                goto yesno;
        case _SC_MEMLOCK_RANGE:
                mib[0] = CTL_KERN;
                mib[1] = KERN_MEMLOCK_RANGE;
                goto yesno;
        case _SC_MEMORY_PROTECTION:
                mib[0] = CTL_KERN;
                mib[1] = KERN_MEMORY_PROTECTION;
                goto yesno;
        case _SC_MONOTONIC_CLOCK:
                mib[0] = CTL_KERN;
                mib[1] = KERN_MONOTONIC_CLOCK;
                goto yesno;
        case _SC_SEMAPHORES:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_SEMAPHORES;
                goto yesno;
        case _SC_TIMERS:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_TIMERS;
                goto yesno;

/* 1003.1c */
        case _SC_LOGIN_NAME_MAX:
                mib[0] = CTL_KERN;
                mib[1] = KERN_LOGIN_NAME_MAX;
                break;
        case _SC_THREADS:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_THREADS;
                goto yesno;

/* 1003.1j */
        case _SC_BARRIERS:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_BARRIERS;
                goto yesno;
        case _SC_SPIN_LOCKS:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_SPIN_LOCKS;
                goto yesno;
        /* Historical; Threads option in 1003.1-2001 */
        case _SC_READER_WRITER_LOCKS:
                mib[0] = CTL_KERN;
                mib[1] = KERN_POSIX_READER_WRITER_LOCKS;
                goto yesno;

/* 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;

/* XPG 4.2 */
        case _SC_IOV_MAX:
                mib[0] = CTL_KERN;
                mib[1] = KERN_IOV_MAX;
                break;
        case _SC_XOPEN_SHM:
                mib[0] = CTL_KERN;
                mib[1] = KERN_SYSVIPC;
                mib[2] = KERN_SYSVIPC_SHM;
                mib_len = 3;
                goto yesno;

/* 1003.1-2001, XSI Option Group */
        case _SC_AIO_LISTIO_MAX:
                if (sysctlgetmibinfo("kern.aio_listio_max", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_AIO_MAX:
                if (sysctlgetmibinfo("kern.aio_max", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_ASYNCHRONOUS_IO:
                if (sysctlgetmibinfo("kern.posix_aio", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                goto yesno;
        case _SC_MESSAGE_PASSING:
                if (sysctlgetmibinfo("kern.posix_msg", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                goto yesno;
        case _SC_MQ_OPEN_MAX:
                if (sysctlgetmibinfo("kern.mqueue.mq_open_max", &mib[0],
                    &mib_len, NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_MQ_PRIO_MAX:
                if (sysctlgetmibinfo("kern.mqueue.mq_prio_max", &mib[0],
                    &mib_len, NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_PRIORITY_SCHEDULING:
                if (sysctlgetmibinfo("kern.posix_sched", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                goto yesno;
        case _SC_ATEXIT_MAX:
                mib[0] = CTL_USER;
                mib[1] = USER_ATEXIT_MAX;
                break;

/* 1003.1-2001, TSF */
        case _SC_GETGR_R_SIZE_MAX:
                return _GETGR_R_SIZE_MAX;
        case _SC_GETPW_R_SIZE_MAX:
                return _GETPW_R_SIZE_MAX;

/* Unsorted */
        case _SC_RTSIG_MAX:
                return SIGRTMAX - SIGRTMIN;
        case _SC_HOST_NAME_MAX:
                return MAXHOSTNAMELEN;
        case _SC_PASS_MAX:
                return _PASSWORD_LEN;
        case _SC_REGEXP:
                return _POSIX_REGEXP;
        case _SC_SHARED_MEMORY_OBJECTS:
                return _POSIX_SHARED_MEMORY_OBJECTS;
        case _SC_SHELL:
                return _POSIX_SHELL;
        case _SC_SPAWN:
                return _POSIX_SPAWN;
        case _SC_SYMLOOP_MAX:
                return MAXSYMLINKS;

yesno:          if (sysctl(mib, mib_len, &value, &len, NULL, 0) == -1)
                        return -1;
                if (value == 0)
                        return -1;
                return value;

/* Extensions */
        case _SC_NPROCESSORS_CONF:
                mib[0] = CTL_HW;
                mib[1] = HW_NCPU;
                break;
        case _SC_NPROCESSORS_ONLN:
                mib[0] = CTL_HW;
                mib[1] = HW_NCPUONLINE;
                break;

/* Linux/Solaris */
        case _SC_PHYS_PAGES:
                len = sizeof(mem);
                mib[0] = CTL_HW;
                mib[1] = HW_PHYSMEM64;
                return (sysctl(mib, 2, &mem, &len, NULL, 0) == -1 ? -1
                    : (long)(mem / _getpagesize()));

        case _SC_AVPHYS_PAGES:
                len = sizeof(uvmexp);
                mib[0] = CTL_VM;
                mib[1] = VM_UVMEXP2;
                return (sysctl(mib, 2, &uvmexp, &len, NULL, 0) == -1 ? -1
                    : (long)(uvmexp.free));

/* Native */
        case _SC_SCHED_RT_TS:
                if (sysctlgetmibinfo("kern.sched.rtts", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_SCHED_PRI_MIN:
                if (sysctlgetmibinfo("kern.sched.pri_min", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_SCHED_PRI_MAX:
                if (sysctlgetmibinfo("kern.sched.pri_max", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))
                        return -1;
                break;
        case _SC_THREAD_DESTRUCTOR_ITERATIONS:
                return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
        case _SC_THREAD_KEYS_MAX:
                return _POSIX_THREAD_KEYS_MAX;
        case _SC_THREAD_STACK_MIN:
                return _getpagesize();
        case _SC_THREAD_THREADS_MAX:
                if (sysctlgetmibinfo("kern.maxproc", &mib[0], &mib_len,
                    NULL, NULL, NULL, SYSCTL_VERSION))  /* XXX */
                        return -1;
                goto yesno;
        case _SC_THREAD_ATTR_STACKADDR:
                return _POSIX_THREAD_ATTR_STACKADDR;
        case _SC_THREAD_ATTR_STACKSIZE:
                return _POSIX_THREAD_ATTR_STACKSIZE;
        case _SC_THREAD_SAFE_FUNCTIONS:
                return _POSIX_THREAD_SAFE_FUNCTIONS;
        case _SC_THREAD_PRIO_PROTECT:
                return _POSIX_THREAD_PRIO_PROTECT;
        case _SC_THREAD_PRIORITY_SCHEDULING:
        case _SC_THREAD_PRIO_INHERIT:
        case _SC_THREAD_PROCESS_SHARED:
                return -1;
        case _SC_TTY_NAME_MAX:
                return pathconf(_PATH_DEV, _PC_NAME_MAX);
        case _SC_TIMER_MAX:
                return _POSIX_TIMER_MAX;
        case _SC_SEM_NSEMS_MAX:
                return LONG_MAX;
        case _SC_CPUTIME:
                return _POSIX_CPUTIME;
        case _SC_THREAD_CPUTIME:
                return _POSIX_THREAD_CPUTIME;
        case _SC_DELAYTIMER_MAX:
                return _POSIX_DELAYTIMER_MAX;
        case _SC_SIGQUEUE_MAX:
                return _POSIX_SIGQUEUE_MAX;
        case _SC_REALTIME_SIGNALS:
                return 200112L;
        default:
                errno = EINVAL;
                return -1;
        }
        return (sysctl(mib, mib_len, &value, &len, NULL, 0) == -1 ? -1
            : value);
}