/*      $NetBSD: linux_sysctl.c,v 1.48 2023/07/10 02:31:55 christos Exp $       */

/*-
 * Copyright (c) 2003, 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Brown.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * sysctl system call.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_sysctl.c,v 1.48 2023/07/10 02:31:55 christos Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/sched.h>
#include <sys/syscallargs.h>
#include <sys/ktrace.h>

#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_ipc.h>
#include <compat/linux/common/linux_sem.h>

#include <compat/linux/linux_syscallargs.h>
#include <compat/linux/common/linux_sysctl.h>
#include <compat/linux/common/linux_exec.h>
#include <compat/linux/common/linux_machdep.h>

char linux_sysname[128] = "Linux";
char linux_release[128] = "6.3.10";
char linux_version[128] = "#1 SMP PREEMPT_DYNAMIC Wed Jun 28 18:34:30 UTC 2023";

struct sysctlnode linux_sysctl_root = {
        .sysctl_flags = SYSCTL_VERSION|
            CTLFLAG_ROOT|CTLTYPE_NODE|CTLFLAG_READWRITE,
        .sysctl_num = 0,
        .sysctl_name = "(linux_root)",
        .sysctl_size = sizeof(struct sysctlnode),
};

extern int linux_enabled;

/*
 * We need an additional sysctllog here since each log can only
 * deal with a single root node.
 */

static struct sysctllog *linux_clog;

void
linux_sysctl_fini(void)
{

        sysctl_teardown(&linux_clog);
        sysctl_free(&linux_sysctl_root);
}

#if !defined(__aarch64__)

SYSCTL_SETUP(linux_sysctl_setup, "linux emulation sysctls")
{
        const struct sysctlnode *node = &linux_sysctl_root;

        sysctl_createv(&linux_clog, 0, &node, &node,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "kern", NULL,
                       NULL, 0, NULL, 0,
                       LINUX_CTL_KERN, CTL_EOL);
        sysctl_createv(&linux_clog, 0, &node, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRING, "ostype", NULL,
                       NULL, 0, linux_sysname, sizeof(linux_sysname),
                       LINUX_KERN_OSTYPE, CTL_EOL);
        sysctl_createv(&linux_clog, 0, &node, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRING, "osrelease", NULL,
                       NULL, 0, linux_release, sizeof(linux_release),
                       LINUX_KERN_OSRELEASE, CTL_EOL);
        sysctl_createv(&linux_clog, 0, &node, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRING, "version", NULL,
                       NULL, 0, linux_version, sizeof(linux_version),
                       LINUX_KERN_VERSION, CTL_EOL);

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "linux",
                       SYSCTL_DESCR("Linux emulation settings"),
                       NULL, 0, NULL, 0,
                       CTL_EMUL, EMUL_LINUX, CTL_EOL);

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "kern",
                       SYSCTL_DESCR("Linux kernel emulation settings"),
                       NULL, 0, NULL, 0,
                       CTL_EMUL, EMUL_LINUX, EMUL_LINUX_KERN, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRING, "ostype",
                       SYSCTL_DESCR("Linux operating system type"),
                       NULL, 0, linux_sysname, sizeof(linux_sysname),
                       CTL_EMUL, EMUL_LINUX, EMUL_LINUX_KERN,
                       EMUL_LINUX_KERN_OSTYPE, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRING, "osrelease",
                       SYSCTL_DESCR("Linux operating system release"),
                       NULL, 0, linux_release, sizeof(linux_release),
                       CTL_EMUL, EMUL_LINUX, EMUL_LINUX_KERN,
                       EMUL_LINUX_KERN_OSRELEASE, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRING, "osversion",
                       SYSCTL_DESCR("Linux operating system revision"),
                       NULL, 0, linux_version, sizeof(linux_version),
                       CTL_EMUL, EMUL_LINUX, EMUL_LINUX_KERN,
                       EMUL_LINUX_KERN_VERSION, CTL_EOL);

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_READWRITE,
                       CTLTYPE_INT, "enabled",
                       SYSCTL_DESCR("Linux compat enabled."),
                       linux_sysctl_enable, 0, &linux_enabled, 0,
                       CTL_EMUL, EMUL_LINUX, CTL_CREATE, CTL_EOL);

        linux_sysctl_root.sysctl_flags &= ~CTLFLAG_READWRITE;
}

/*
 * linux sysctl system call
 */
int
linux_sys___sysctl(struct lwp *l, const struct linux_sys___sysctl_args *uap, register_t *retval)
{
        struct linux___sysctl ls;
        int error, nerror, name[CTL_MAXNAME];
        size_t savelen = 0, oldlen = 0;

        /*
         * get linux args structure
         */
        if ((error = copyin(SCARG(uap, lsp), &ls, sizeof(ls))))
                return error;

        /*
         * get oldlen
         */
        oldlen = 0;
        if (ls.oldlenp != NULL) {
                error = copyin(ls.oldlenp, &oldlen, sizeof(oldlen));
                if (error)
                        return (error);
        }
        savelen = oldlen;

        /*
         * top-level sysctl names may or may not be non-terminal, but
         * we don't care
         */
        if (ls.nlen > CTL_MAXNAME || ls.nlen < 1)
                return (ENOTDIR);
        error = copyin(ls.name, &name, ls.nlen * sizeof(int));
        if (error)
                return (error);

        ktrmib(name, ls.nlen);

        /*
         * dispatch request into linux sysctl tree
         */
        sysctl_lock(ls.newval != NULL);
        error = sysctl_dispatch(&name[0], ls.nlen,
                                ls.oldval, &oldlen,
                                ls.newval, ls.newlen,
                                &name[0], l, &linux_sysctl_root);
        sysctl_unlock();

        /*
         * reset caller's oldlen, even if we got an error
         */
        if (ls.oldlenp) {
                nerror = copyout(&oldlen, ls.oldlenp, sizeof(oldlen));
                if (error == 0)
                        error = nerror;
        }

        /*
         * if the only problem is that we weren't given enough space,
         * that's an ENOMEM error
         */
        if (error == 0 && ls.oldval != NULL && savelen < oldlen)
                error = ENOMEM;

        return (error);
}
#endif