/*      $NetBSD: freebsd_sysctl.c,v 1.19 2015/02/14 07:37:19 dholland Exp $     */

/*-
 * Copyright (c) 2005 The NetBSD Foundation, Inc.
 * 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.
 *
 * 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.
 */

/*
 * FreeBSD compatibility module. Try to deal with various FreeBSD sysctl calls.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: freebsd_sysctl.c,v 1.19 2015/02/14 07:37:19 dholland Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/sysctl.h>
#include <sys/ktrace.h>

#include <sys/syscallargs.h>

#include <compat/freebsd/freebsd_syscallargs.h>
#include <compat/common/compat_util.h>
#include <compat/freebsd/freebsd_rtprio.h>
#include <compat/freebsd/freebsd_timex.h>
#include <compat/freebsd/freebsd_signal.h>
#include <compat/freebsd/freebsd_mman.h>
#include <compat/freebsd/freebsd_sysctl.h>

static int freebsd_sysctl_name2oid(char *, int *, int *);

static struct sysctllog *freebsd_clog;

void
freebsd_sysctl_init(void)
{

        sysctl_createv(&freebsd_clog, 0, NULL, NULL,
                        CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE,
                        CTLTYPE_INT, "osreldate",
                        SYSCTL_DESCR("Operating system revision"),
                        NULL, __NetBSD_Version__, NULL, 0,
                        CTL_KERN, CTL_CREATE, CTL_EOL);
}

void
freebsd_sysctl_fini(void)
{

        sysctl_teardown(&freebsd_clog);
}

int
freebsd_sys_sysctl(struct lwp *l, const struct freebsd_sys_sysctl_args *uap, register_t *retval)
{
        /* {
                syscallarg(int *) name;
                syscallarg(u_int) namelen;
                syscallarg(void *) old;
                syscallarg(size_t *) oldlenp;
                syscallarg(void *) new;
                syscallarg(size_t) newlen;
        } */
        int error;
        int name[CTL_MAXNAME];
        size_t newlen, *oldlenp, oldlen;
        u_int namelen;
        void *new, *old;

        namelen = SCARG(uap, namelen);

        if ((namelen > CTL_MAXNAME) || (namelen < 1))
                return EINVAL;

        if ((error = copyin(SCARG(uap, name), name, 
            namelen * sizeof(*name))) != 0)
                return error;

        if (namelen > 0 && name[0] != 0)
                return(sys___sysctl(l, (const void *)uap, retval));

        ktrmib(name, namelen);

        /*
         * FreeBSD sysctl uses an undocumented set of special OIDs in its
         * sysctl MIB whose tree is rooted at oid 0.  These OIDs are
         * interpreted by their sysctl to implement functions that NetBSD
         * performs in libc, such as sysctlgetmibinfo.
         *
         * From the FreeBSD kern_sysctl.c, these OIDs are:
         * {0,0}        printf the entire MIB-tree.
         * {0,1,...}    return the name of the "..." OID.
         * {0,2,...}    return the next OID.
         * {0,3}        return the OID of the name in "new"
         * {0,4,...}    return the kind & format info for the "..." OID.
         * {0,5,...}    return the description the "..." OID.
         *
         * Only implement {0,3} for now.
         */

        if (namelen < 2 || namelen > CTL_MAXNAME)
                return(EINVAL);

        if (name[1] == 3) {
                char *locnew;
                int oid[CTL_MAXNAME];
                u_int oidlen = CTL_MAXNAME;

                new = SCARG(uap, new);
                newlen = SCARG(uap, newlen);
                if (new == NULL || newlen < 1 ||
                    newlen > (SYSCTL_NAMELEN * CTL_MAXNAME))
                        return(EINVAL);

                old = SCARG(uap, old);
                oldlenp = SCARG(uap, oldlenp);
                if (old == NULL || oldlenp == NULL)
                        return(EINVAL);

                if ((error = copyin(oldlenp, &oldlen, sizeof(oldlen))))
                        return (error);
                if (oldlen < sizeof(int))
                        return (EINVAL);

                if ((locnew =
                     (char *) malloc(newlen + 1, M_TEMP, M_WAITOK)) == NULL)
                        return(ENOMEM);

                if ((error = copyinstr(new, locnew, newlen + 1, NULL))) {
                        free(locnew, M_TEMP);
                        return(error);
                }

                ktrmibio(-1, UIO_WRITE, new, newlen + 1, error);
                sysctl_lock(new != NULL);
                error = freebsd_sysctl_name2oid(locnew, oid, &oidlen);
                sysctl_unlock();
                free(locnew, M_TEMP);
                if (error)
                        return(error);

                oidlen *= sizeof(int);
                error = copyout(oid, SCARG(uap, old),
                                MIN(oidlen, oldlen));
                if (error)
                        return(error);
                ktrmibio(-1, UIO_READ, SCARG(uap, old),
                    MIN(oidlen, oldlen),  0);

                error = copyout(&oidlen, SCARG(uap, oldlenp), sizeof(u_int));

                return(error);
        }

        return(EOPNOTSUPP);
}

static int
freebsd_sysctl_name2oid(char *name, int *oid, int *oidlen)
{
        char *dot;
        int oi, ci;
        struct sysctlnode *node, *pnode;

        pnode = &sysctl_root;
        node = sysctl_root.sysctl_child;
        oi = 0;
        if ((dot = strchr(name, (int)'.')) != NULL)
                *dot++ = '\0';

next:
        while (*name != '\0' && node != NULL) {
                for (ci = 0; ci < pnode->sysctl_clen; ci++) {
                        if (strcmp(name, node[ci].sysctl_name) == 0) {
                                oid[oi++] = node[ci].sysctl_num;
                                if ((name = dot) == NULL) {
                                        *oidlen = oi;
                                        return(0);
                                }
                                if ((dot = strchr(name, (int)'.')) != NULL)
                                        *dot++ = '\0';

                                if (SYSCTL_TYPE(node[ci].sysctl_flags) !=
                                    CTLTYPE_NODE)
                                        return(ENOTDIR);

                                pnode = &node[ci];
                                node = pnode->sysctl_child;
                                goto next;
                        }
                }

                /* no more nodes, it must not exist */
                break;
        }

        return(ENOENT);
}