/*      $NetBSD: sysctl.c,v 1.43 2026/07/10 21:54:30 kre Exp $  */

/*-
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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[] = "@(#)sysctl.c    8.2 (Berkeley) 1/4/94";
#else
__RCSID("$NetBSD: sysctl.c,v 1.43 2026/07/10 21:54:30 kre Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/param.h>
#define __COMPAT_SYSCTL
#include <sys/sysctl.h>

#include <assert.h>
#include <errno.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "extern.h"

#ifdef __weak_alias
__weak_alias(sysctl,_sysctl)
#endif

/*
 * handles requests off the user subtree
 */
static int user_sysctl(const int *, u_int, void *, size_t *,
                        const void *, size_t);

/*
 * copies out individual nodes taking target version into account
 */
static size_t __cvt_node_out(uint, const struct sysctlnode *, void **,
                             size_t *);

#include <stdlib.h>

int
sysctl(const int *name, unsigned int namelen,
        void *oldp, size_t *oldlenp,
        const void *newp, size_t newlen)
{
        size_t oldlen, savelen;
        int error;

        if (name[0] != CTL_USER)
                return (__sysctl(name, namelen, oldp, oldlenp,
                                 newp, newlen));

        oldlen = (oldlenp == NULL) ? 0 : *oldlenp;
        savelen = oldlen;
        error = user_sysctl(name + 1, namelen - 1, oldp, &oldlen, newp, newlen);

        if (error != 0) {
                errno = error;
                return (-1);
        }

        if (oldlenp != NULL) {
                *oldlenp = oldlen;
                if (oldp != NULL && oldlen > savelen) {
                        errno = ENOMEM;
                        return (-1);
                }
        }

        return (0);
}

static int
user_sysctl(const int *name, unsigned int namelen,
        void *oldp, size_t *oldlenp,
        const void *newp, size_t newlen)
{
#ifndef SMALL
#define X(a)    a
#else
#define X(a)    ""
#endif
#define _INT(s, n, v, d) {                                      \
        .sysctl_flags = CTLFLAG_IMMEDIATE|CTLFLAG_PERMANENT|    \
                        CTLTYPE_INT|SYSCTL_VERSION,             \
        .sysctl_size = sizeof(int),                             \
        .sysctl_name = (s),                                     \
        .sysctl_num = (n),                                      \
        .sysctl_un.scu_idata = (v),                             \
        .sysctl_desc = X(d),                                    \
        }

#define _STRING(s, n, v, d) {                                   \
        .sysctl_flags = SYSCTL_VERSION|CTLFLAG_PERMANENT|CTLTYPE_STRING, \
        .sysctl_size = sizeof(v),                               \
        .sysctl_name = (s),                                     \
        .sysctl_num = (n),                                      \
        .sysctl_data = __UNCONST(v),                            \
        .sysctl_desc = X(d),                                    \
        }

        /*
         * the nodes under the "user" node
         */
        static const struct sysctlnode sysctl_usermib[] = {
                _STRING("cs_path", USER_CS_PATH, _PATH_STDPATH,
                        "A value for the PATH environment variable "
                        "that finds all the standard utilities"),
                _INT("bc_base_max", USER_BC_BASE_MAX, BC_BASE_MAX,
                     "The maximum ibase/obase values in the bc(1) utility"),
                _INT("bc_dim_max", USER_BC_DIM_MAX, BC_DIM_MAX,
                     "The maximum array size in the bc(1) utility"),
                _INT("bc_scale_max", USER_BC_SCALE_MAX, BC_SCALE_MAX,
                     "The maximum scale value in the bc(1) utility"),
                _INT("bc_string_max", USER_BC_STRING_MAX, BC_STRING_MAX,
                     "The maximum string length in the bc(1) utility"),
                _INT("coll_weights_max", USER_COLL_WEIGHTS_MAX,
                     COLL_WEIGHTS_MAX, "The maximum number of weights that can "
                     "be assigned to any entry of the LC_COLLATE order keyword "
                     "in the locale definition file"),
                _INT("expr_nest_max", USER_EXPR_NEST_MAX, EXPR_NEST_MAX,
                     "The maximum number of expressions that can be nested "
                     "within parenthesis by the expr(1) utility"),
                _INT("line_max", USER_LINE_MAX, LINE_MAX, "The maximum length "
                     "in bytes of a text-processing utility's input line"),
                _INT("re_dup_max", USER_RE_DUP_MAX, RE_DUP_MAX, "The maximum "
                     "number of repeated occurrences of a regular expression "
                     "permitted when using interval notation"),
                _INT("posix2_version", USER_POSIX2_VERSION, _POSIX2_VERSION,
                     "The version of POSIX 1003.2 with which the system "
                     "attempts to comply"),
#ifdef _POSIX2_C_BIND
                _INT("posix2_c_bind", USER_POSIX2_C_BIND, 1,
                     "Whether the system's C-language development facilities "
                     "support the C-Language Bindings Option"),
#else
                _INT("posix2_c_bind", USER_POSIX2_C_BIND, 0,
                     "Whether the system's C-language development facilities "
                     "support the C-Language Bindings Option"),
#endif
#ifdef POSIX2_C_DEV
                _INT("posix2_c_dev", USER_POSIX2_C_DEV, 1,
                     "Whether the system supports the C-Language Development "
                     "Utilities Option"),
#else
                _INT("posix2_c_dev", USER_POSIX2_C_DEV, 0,
                     "Whether the system supports the C-Language Development "
                     "Utilities Option"),
#endif
#ifdef POSIX2_CHAR_TERM
                _INT("posix2_char_term", USER_POSIX2_CHAR_TERM, 1,
                     "Whether the system supports at least one terminal type "
                     "capable of all operations described in POSIX 1003.2"),
#else
                _INT("posix2_char_term", USER_POSIX2_CHAR_TERM, 0,
                     "Whether the system supports at least one terminal type "
                     "capable of all operations described in POSIX 1003.2"),
#endif
#ifdef POSIX2_FORT_DEV
                _INT("posix2_fort_dev", USER_POSIX2_FORT_DEV, 1,
                     "Whether the system supports the FORTRAN Development "
                     "Utilities Option"),
#else
                _INT("posix2_fort_dev", USER_POSIX2_FORT_DEV, 0,
                     "Whether the system supports the FORTRAN Development "
                     "Utilities Option"),
#endif
#ifdef POSIX2_FORT_RUN
                _INT("posix2_fort_run", USER_POSIX2_FORT_RUN, 1,
                     "Whether the system supports the FORTRAN Runtime "
                     "Utilities Option"),
#else
                _INT("posix2_fort_run", USER_POSIX2_FORT_RUN, 0,
                     "Whether the system supports the FORTRAN Runtime "
                     "Utilities Option"),
#endif
#ifdef POSIX2_LOCALEDEF
                _INT("posix2_localedef", USER_POSIX2_LOCALEDEF, 1,
                     "Whether the system supports the creation of locales"),
#else
                _INT("posix2_localedef", USER_POSIX2_LOCALEDEF, 0,
                     "Whether the system supports the creation of locales"),
#endif
#ifdef POSIX2_SW_DEV
                _INT("posix2_sw_dev", USER_POSIX2_SW_DEV, 1,
                     "Whether the system supports the Software Development "
                     "Utilities Option"),
#else
                _INT("posix2_sw_dev", USER_POSIX2_SW_DEV, 0,
                     "Whether the system supports the Software Development "
                     "Utilities Option"),
#endif
#ifdef POSIX2_UPE
                _INT("posix2_upe", USER_POSIX2_UPE, 1,
                     "Whether the system supports the User Portability "
                     "Utilities Option"),
#else
                _INT("posix2_upe", USER_POSIX2_UPE, 0,
                     "Whether the system supports the User Portability "
                     "Utilities Option"),
#endif
                _INT("stream_max", USER_STREAM_MAX, FOPEN_MAX,
                     "The minimum maximum number of streams that a process "
                     "may have open at any one time"),
                _INT("tzname_max", USER_TZNAME_MAX, _TZNAME_MAXIMUM,
                     "The minimum maximum number of bytes supported for the "
                     "name of a timezone abbreviation"),
                _INT("atexit_max", USER_ATEXIT_MAX, -1,
                     "The maximum number of functions that may be registered "
                     "with atexit(3)"),

#ifdef USER_OSTYPE_VALUE
                _STRING("ostype", USER_OSTYPE, USER_OSTYPE_VALUE,
                     "The name of the operating system"),
#endif
#ifdef USER_OSREVISION_VALUE
                _INT("osrevision", USER_OSREVISION, USER_OSREVISION_VALUE,
                     "A numeric representation of the OS version"),
#endif
#ifdef USER_OSRELEASE_VALUE
                _STRING("osrelease", USER_OSRELEASE, USER_OSRELEASE_VALUE,
                     "The system version of the libraries & utilities"),
#endif
#ifdef USER_BUILDTIME_VALUE
                _STRING("built", USER_BUILDTIME, USER_BUILDTIME_VALUE,
                     "The date & time (UTC) at which libc was last built "
                     "- if with a trailing '!' the reproducible build time"),
#endif
        };
#undef X
#undef _INT
#undef _STRING

        static const int clen = sizeof(sysctl_usermib) /
                sizeof(sysctl_usermib[0]);

        const struct sysctlnode *node;
        int ni;
        size_t l, sz;

        /*
         * none of these nodes are writable and they're all terminal (for now)
         */
        if (namelen != 1)
                return (EINVAL);

        l = *oldlenp;
        if (name[0] == CTL_QUERY) {
                uint v;
                node = newp;
                if (node == NULL)
                        return (EINVAL);
                else if (SYSCTL_VERS(node->sysctl_flags) == SYSCTL_VERS_1 &&
                         newlen == sizeof(struct sysctlnode))
                        v = SYSCTL_VERS_1;
                else
                        return (EINVAL);

                sz = 0;
                for (ni = 0; ni < clen; ni++)
                        sz += __cvt_node_out(v, &sysctl_usermib[ni], &oldp, &l);
                *oldlenp = sz;
                return (0);
        }

        if (name[0] == CTL_DESCRIBE) {
                /*
                 * XXX make sure this is larger than the largest
                 * "user" description
                 */
                char buf[192];
                struct sysctldesc *d1 = (void *)&buf[0], *d2 = oldp;
                size_t d;

                node = newp;
                if (node != NULL &&
                    (SYSCTL_VERS(node->sysctl_flags) < SYSCTL_VERS_1 ||
                     newlen != sizeof(struct sysctlnode)))
                        return (EINVAL);

                sz = 0;
                for (ni = 0; ni < clen; ni++) {
                        memset(&buf[0], 0, sizeof(buf));
                        if (node != NULL &&
                            node->sysctl_num != sysctl_usermib[ni].sysctl_num)
                                continue;
                        d1->descr_num = sysctl_usermib[ni].sysctl_num;
                        d1->descr_ver = sysctl_usermib[ni].sysctl_ver;
                        if (sysctl_usermib[ni].sysctl_desc == NULL)
                                d1->descr_len = 1;
                        else {
                                size_t dlen;
                                (void)strlcpy(d1->descr_str,
                                        sysctl_usermib[ni].sysctl_desc,
                                        sizeof(buf) - sizeof(*d1));
                                dlen = strlen(d1->descr_str) + 1;
                                _DIAGASSERT(__type_fit(uint32_t, dlen));
                                d1->descr_len = (uint32_t)dlen;
                        }
                        d = (size_t)__sysc_desc_len(d1->descr_len);
                        if (d2 != NULL)
                                memcpy(d2, d1, d);
                        sz += d;
                        d2 = (void *)((char *)(void *)d2 + d);
                        if (node != NULL)
                                break;
                }
                *oldlenp = sz;
                if (sz == 0 && node != NULL)
                        return (ENOENT);
                return (0);

        }

        /*
         * none of these nodes are writable
         */
        if (newp != NULL || newlen != 0)
                return (EPERM);
        
        node = &sysctl_usermib[0];
        for (ni = 0; ni < clen; ni++)
                if (name[0] == node[ni].sysctl_num)
                        break;
        if (ni == clen)
                return (EOPNOTSUPP);

        node = &node[ni];
        if (node->sysctl_flags & CTLFLAG_IMMEDIATE) {
                switch (SYSCTL_TYPE(node->sysctl_flags)) {
                case CTLTYPE_INT:
                        newp = &node->sysctl_idata;
                        break;
                case CTLTYPE_QUAD:
                        newp = &node->sysctl_qdata;
                        break;
                default:
                        return (EINVAL);
                }
        }
        else
                newp = node->sysctl_data;

        l = MIN(l, node->sysctl_size);
        if (oldp != NULL)
                memcpy(oldp, newp, l);
        *oldlenp = node->sysctl_size;

        return (0);
}

static size_t
__cvt_node_out(uint v, const struct sysctlnode *n, void **o, size_t *l)
{
        const void *src = n;
        size_t sz;

        switch (v) {
#if (SYSCTL_VERSION != SYSCTL_VERS_1)
#error __cvt_node_out: no support for SYSCTL_VERSION
#endif /* (SYSCTL_VERSION != SYSCTL_VERS_1) */

        case SYSCTL_VERSION:
                sz = sizeof(struct sysctlnode);
                break;

        default:
                sz = 0;
                break;
        }

        if (sz > 0 && *o != NULL && *l >= sz) {
                memcpy(*o, src, sz);
                *o = sz + (caddr_t)*o;
                *l -= sz;
        }

        return(sz);
}