dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / kernel / fs / nfs / nfs_export.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 *      Copyright 1983, 1984, 1985, 1986, 1987, 1988, 1989  AT&T.
 *              All rights reserved.
 */


#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/uio.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/file.h>
#include <sys/tiuser.h>
#include <sys/kmem.h>
#include <sys/pathname.h>
#include <sys/debug.h>
#include <sys/vtrace.h>
#include <sys/cmn_err.h>
#include <sys/acl.h>
#include <sys/utsname.h>
#include <sys/sdt.h>
#include <netinet/in.h>
#include <sys/avl.h>

#include <rpc/types.h>
#include <rpc/auth.h>
#include <rpc/svc.h>

#include <nfs/nfs.h>
#include <nfs/export.h>
#include <nfs/nfssys.h>
#include <nfs/nfs_clnt.h>
#include <nfs/nfs_acl.h>
#include <nfs/nfs_log.h>
#include <nfs/lm.h>
#include <sys/sunddi.h>
#include <sys/pkp_hash.h>

treenode_t *ns_root;

struct exportinfo *exptable_path_hash[PKP_HASH_SIZE];
struct exportinfo *exptable[EXPTABLESIZE];

static int      unexport(exportinfo_t *);
static void     exportfree(exportinfo_t *);
static int      loadindex(exportdata_t *);

extern void     nfsauth_cache_free(exportinfo_t *);
extern int      sec_svc_loadrootnames(int, int, caddr_t **, model_t);
extern void     sec_svc_freerootnames(int, int, caddr_t *);

static int build_seclist_nodups(exportdata_t *, secinfo_t *, int);
static void srv_secinfo_add(secinfo_t **, int *, secinfo_t *, int, int);
static void srv_secinfo_remove(secinfo_t **, int *, secinfo_t *, int);
static void srv_secinfo_treeclimb(exportinfo_t *, secinfo_t *, int, bool_t);

#ifdef VOLATILE_FH_TEST
static struct ex_vol_rename *find_volrnm_fh(exportinfo_t *, nfs_fh4 *);
static uint32_t find_volrnm_fh_id(exportinfo_t *, nfs_fh4 *);
static void free_volrnm_list(exportinfo_t *);
#endif /* VOLATILE_FH_TEST */

/*
 * exported_lock        Read/Write lock that protects the exportinfo list.
 *                      This lock must be held when searching or modifiying
 *                      the exportinfo list.
 */
krwlock_t exported_lock;

/*
 * "public" and default (root) location for public filehandle
 */
struct exportinfo *exi_public, *exi_root;

fid_t exi_rootfid;      /* for checking the default public file handle */

fhandle_t nullfh2;      /* for comparing V2 filehandles */

/*
 * macro for static dtrace probes to trace server namespace ref count mods.
 */
#define SECREF_TRACE(seclist, tag, flav, aftcnt) \
        DTRACE_PROBE4(nfss__i__nmspc__secref, struct secinfo *, (seclist), \
                char *, (tag), int, (int)(flav), int, (int)(aftcnt))


#define exptablehash(fsid, fid) (nfs_fhhash((fsid), (fid)) & (EXPTABLESIZE - 1))

static uint8_t
xor_hash(uint8_t *data, int len)
{
        uint8_t h = 0;

        while (len--)
                h ^= *data++;

        return (h);
}

/*
 * File handle hash function, XOR over all bytes in fsid and fid.
 */
static unsigned
nfs_fhhash(fsid_t *fsid, fid_t *fid)
{
        int len;
        uint8_t h;

        h = xor_hash((uint8_t *)fsid, sizeof (fsid_t));

        /*
         * Sanity check the length before using it
         * blindly in case the client trashed it.
         */
        len = fid->fid_len > NFS_FH4MAXDATA ? 0 : fid->fid_len;
        h ^= xor_hash((uint8_t *)fid->fid_data, len);

        return ((unsigned)h);
}

/*
 * Free the memory allocated within a secinfo entry.
 */
void
srv_secinfo_entry_free(struct secinfo *secp)
{
        if (secp->s_rootcnt > 0 && secp->s_rootnames != NULL) {
                sec_svc_freerootnames(secp->s_secinfo.sc_rpcnum,
                    secp->s_rootcnt, secp->s_rootnames);
                secp->s_rootcnt = 0;
        }

        if ((secp->s_secinfo.sc_rpcnum == RPCSEC_GSS) &&
            (secp->s_secinfo.sc_gss_mech_type)) {
                kmem_free(secp->s_secinfo.sc_gss_mech_type->elements,
                    secp->s_secinfo.sc_gss_mech_type->length);
                kmem_free(secp->s_secinfo.sc_gss_mech_type,
                    sizeof (rpc_gss_OID_desc));
                secp->s_secinfo.sc_gss_mech_type = NULL;
        }
}

/*
 * Free a list of secinfo allocated in the exportdata structure.
 */
void
srv_secinfo_list_free(struct secinfo *secinfo, int cnt)
{
        int i;

        if (cnt == 0)
                return;

        for (i = 0; i < cnt; i++)
                srv_secinfo_entry_free(&secinfo[i]);

        kmem_free(secinfo, cnt * sizeof (struct secinfo));
}

/*
 * Allocate and copy a secinfo data from "from" to "to".
 *
 * This routine is used by srv_secinfo_add() to add a new flavor to an
 * ancestor's export node. The rootnames are not copied because the
 * allowable rootname access only applies to the explicit exported node,
 * not its ancestor's.
 *
 * "to" should have already been allocated and zeroed before calling
 * this routine.
 *
 * This routine is used under the protection of exported_lock (RW_WRITER).
 */
void
srv_secinfo_copy(struct secinfo *from, struct secinfo *to)
{
        to->s_secinfo.sc_nfsnum = from->s_secinfo.sc_nfsnum;
        to->s_secinfo.sc_rpcnum = from->s_secinfo.sc_rpcnum;

        if (from->s_secinfo.sc_rpcnum == RPCSEC_GSS) {
                to->s_secinfo.sc_service = from->s_secinfo.sc_service;
                bcopy(from->s_secinfo.sc_name, to->s_secinfo.sc_name,
                    strlen(from->s_secinfo.sc_name));
                bcopy(from->s_secinfo.sc_gss_mech, to->s_secinfo.sc_gss_mech,
                    strlen(from->s_secinfo.sc_gss_mech));

                /* copy mechanism oid */
                to->s_secinfo.sc_gss_mech_type =
                    kmem_alloc(sizeof (rpc_gss_OID_desc), KM_SLEEP);
                to->s_secinfo.sc_gss_mech_type->length =
                    from->s_secinfo.sc_gss_mech_type->length;
                to->s_secinfo.sc_gss_mech_type->elements =
                    kmem_alloc(from->s_secinfo.sc_gss_mech_type->length,
                    KM_SLEEP);
                bcopy(from->s_secinfo.sc_gss_mech_type->elements,
                    to->s_secinfo.sc_gss_mech_type->elements,
                    from->s_secinfo.sc_gss_mech_type->length);
        }

        to->s_refcnt = from->s_refcnt;
        to->s_window = from->s_window;
        /* no need to copy the mode bits - s_flags */
}

/*
 * Create a secinfo array without duplicates.  The condensed
 * flavor list is used to propagate flavor ref counts  to an
 * export's ancestor pseudonodes.
 */
static int
build_seclist_nodups(exportdata_t *exd, secinfo_t *nodups, int exponly)
{
        int ccnt, c;
        int ncnt, n;
        struct secinfo *cursec;

        ncnt = 0;
        ccnt = exd->ex_seccnt;
        cursec = exd->ex_secinfo;

        for (c = 0; c < ccnt; c++) {

                if (exponly && ! SEC_REF_EXPORTED(&cursec[c]))
                        continue;

                for (n = 0; n < ncnt; n++) {
                        if (nodups[n].s_secinfo.sc_nfsnum ==
                            cursec[c].s_secinfo.sc_nfsnum)
                                break;
                }

                /*
                 * The structure copy below also copys ptrs embedded
                 * within struct secinfo.  The ptrs are copied but
                 * they are never freed from the nodups array.  If
                 * an ancestor's secinfo array doesn't contain one
                 * of the nodups flavors, then the entry is properly
                 * copied into the ancestor's secinfo array.
                 * (see srv_secinfo_copy)
                 */
                if (n == ncnt) {
                        nodups[n] = cursec[c];
                        ncnt++;
                }
        }
        return (ncnt);
}

/*
 * Add the new security flavors from newdata to the current list, pcursec.
 * Upon return, *pcursec has the newly merged secinfo list.
 *
 * There should be at least 1 secinfo entry in newsec.
 *
 * This routine is used under the protection of exported_lock (RW_WRITER).
 */
static void
srv_secinfo_add(secinfo_t **pcursec, int *pcurcnt, secinfo_t *newsec,
    int newcnt, int is_pseudo)
{
        int ccnt, c;            /* sec count in current data - curdata */
        int n;                  /* index for newsec  - newsecinfo */
        int tcnt;               /* total sec count after merge */
        int mcnt;               /* total sec count after merge */
        struct secinfo *msec;   /* merged secinfo list */
        struct secinfo *cursec;

        cursec = *pcursec;
        ccnt = *pcurcnt;

        ASSERT(newcnt > 0);
        tcnt = ccnt + newcnt;

        for (n = 0; n < newcnt; n++) {
                for (c = 0; c < ccnt; c++) {
                        if (newsec[n].s_secinfo.sc_nfsnum ==
                            cursec[c].s_secinfo.sc_nfsnum) {
                                cursec[c].s_refcnt += newsec[n].s_refcnt;
                                SECREF_TRACE(cursec, "add_ref",
                                    cursec[c].s_secinfo.sc_nfsnum,
                                    cursec[c].s_refcnt);
                                tcnt--;
                                break;
                        }
                }
        }

        if (tcnt == ccnt)
                return; /* no change; no new flavors */

        msec = kmem_zalloc(tcnt * sizeof (struct secinfo), KM_SLEEP);

        /* move current secinfo list data to the new list */
        for (c = 0; c < ccnt; c++)
                msec[c] = cursec[c];

        /* Add the flavor that's not in the current data */
        mcnt = ccnt;
        for (n = 0; n < newcnt; n++) {
                for (c = 0; c < ccnt; c++) {
                        if (newsec[n].s_secinfo.sc_nfsnum ==
                            cursec[c].s_secinfo.sc_nfsnum)
                                break;
                }

                /* This is the one. Add it. */
                if (c == ccnt) {
                        srv_secinfo_copy(&newsec[n], &msec[mcnt]);

                        if (is_pseudo)
                                msec[mcnt].s_flags = M_RO;

                        SECREF_TRACE(msec, "new_ref",
                            msec[mcnt].s_secinfo.sc_nfsnum,
                            msec[mcnt].s_refcnt);
                        mcnt++;
                }
        }

        ASSERT(mcnt == tcnt);

        /*
         * Done. Update curdata. Free the old secinfo list in
         * curdata and return the new sec array info
         */
        if (ccnt > 0)
                kmem_free(cursec, ccnt * sizeof (struct secinfo));
        *pcurcnt = tcnt;
        *pcursec = msec;
}

/*
 * For NFS V4.
 * Remove the security data of the unexported node from its ancestors.
 * Assume there is at least one flavor entry in the current sec list
 * (pcursec).
 *
 * This routine is used under the protection of exported_lock (RW_WRITER).
 *
 * Every element of remsec is an explicitly exported flavor.  If
 * srv_secinfo_remove() is called fom an exportfs error path, then
 * the flavor list was derived from the user's share cmdline,
 * and all flavors are explicit.  If it was called from the unshare path,
 * build_seclist_nodups() was called with the exponly flag.
 */
static void
srv_secinfo_remove(secinfo_t **pcursec, int *pcurcnt, secinfo_t *remsec,
    int remcnt)
{
        int ccnt, c;            /* sec count in current data - cursec */
        int r;                  /* sec count in removal data - remsec */
        int tcnt, mcnt;         /* total sec count after removing */
        struct secinfo *msec;   /* final secinfo list after removing */
        struct secinfo *cursec;

        cursec = *pcursec;
        ccnt = *pcurcnt;
        tcnt = ccnt;

        for (r = 0; r < remcnt; r++) {
                /*
                 * At unshare/reshare time, only explicitly shared flavor ref
                 * counts are decremented and propagated to ancestors.
                 * Implicit flavor refs came from shared descendants, and
                 * they must be kept.
                 */
                if (! SEC_REF_EXPORTED(&remsec[r]))
                        continue;

                for (c = 0; c < ccnt; c++) {
                        if (remsec[r].s_secinfo.sc_nfsnum ==
                            cursec[c].s_secinfo.sc_nfsnum) {

                                /*
                                 * Decrement secinfo reference count by 1.
                                 * If this entry is invalid after decrementing
                                 * the count (i.e. count < 1), this entry will
                                 * be removed.
                                 */
                                cursec[c].s_refcnt--;

                                SECREF_TRACE(cursec, "del_ref",
                                    cursec[c].s_secinfo.sc_nfsnum,
                                    cursec[c].s_refcnt);

                                ASSERT(cursec[c].s_refcnt >= 0);

                                if (SEC_REF_INVALID(&cursec[c]))
                                        tcnt--;
                                break;
                        }
                }
        }

        ASSERT(tcnt >= 0);
        if (tcnt == ccnt)
                return; /* no change; no flavors to remove */

        if (tcnt == 0) {
                srv_secinfo_list_free(cursec, ccnt);
                *pcurcnt = 0;
                *pcursec = NULL;
                return;
        }

        msec = kmem_zalloc(tcnt * sizeof (struct secinfo), KM_SLEEP);

        /* walk thru the given secinfo list to remove the flavors */
        mcnt = 0;
        for (c = 0; c < ccnt; c++) {
                if (SEC_REF_INVALID(&cursec[c])) {
                        srv_secinfo_entry_free(&cursec[c]);
                } else {
                        msec[mcnt] = cursec[c];
                        mcnt++;
                }
        }

        ASSERT(mcnt == tcnt);
        /*
         * Done. Update curdata.
         * Free the existing secinfo list in curdata. All pointers
         * within the list have either been moved to msec or freed
         * if it's invalid.
         */
        kmem_free(*pcursec, ccnt * sizeof (struct secinfo));
        *pcursec = msec;
        *pcurcnt = tcnt;
}


/*
 * For the reshare case, sec flavor accounting happens in 3 steps:
 * 1) propagate addition of new flavor refs up the ancestor tree
 * 2) transfer flavor refs of descendants to new/reshared exportdata
 * 3) propagate removal of old flavor refs up the ancestor tree
 *
 * srv_secinfo_exp2exp() implements step 2 of a reshare.  At this point,
 * the new flavor list has already been propagated up through the
 * ancestor tree via srv_secinfo_treeclimb().
 *
 * If there is more than 1 export reference to an old flavor (i.e. some
 * of its children shared with this flavor), this flavor information
 * needs to be transferred to the new exportdata struct.  A flavor in
 * the old exportdata has descendant refs when its s_refcnt > 1 or it
 * is implicitly shared (M_SEC4_EXPORTED not set in s_flags).
 *
 * SEC_REF_EXPORTED() is only true when  M_SEC4_EXPORTED is set
 * SEC_REF_SELF() is only true when both M_SEC4_EXPORTED is set and s_refcnt==1
 *
 * Transferring descendant flavor refcnts happens in 2 passes:
 * a) flavors used before (oldsecinfo) and after (curdata->ex_secinfo) reshare
 * b) flavors used before but not after reshare
 *
 * This routine is used under the protection of exported_lock (RW_WRITER).
 */
void
srv_secinfo_exp2exp(exportdata_t *curdata, secinfo_t *oldsecinfo, int ocnt)
{
        int ccnt, c;            /* sec count in current data - curdata */
        int o;                  /* sec count in old data - oldsecinfo */
        int tcnt, mcnt;         /* total sec count after the transfer */
        struct secinfo *msec;   /* merged secinfo list */

        ccnt = curdata->ex_seccnt;

        ASSERT(ocnt > 0);
        ASSERT(!(curdata->ex_flags & EX_PSEUDO));

        /*
         * If the oldsecinfo has flavors with more than 1 reference count
         * and the flavor is specified in the reshare, transfer the flavor
         * refs to the new seclist (curdata.ex_secinfo).
         */
        tcnt = ccnt + ocnt;

        for (o = 0; o < ocnt; o++) {

                if (SEC_REF_SELF(&oldsecinfo[o])) {
                        tcnt--;
                        continue;
                }

                for (c = 0; c < ccnt; c++) {
                        if (oldsecinfo[o].s_secinfo.sc_nfsnum ==
                            curdata->ex_secinfo[c].s_secinfo.sc_nfsnum) {

                                /*
                                 * add old reference to the current
                                 * secinfo count
                                 */
                                curdata->ex_secinfo[c].s_refcnt +=
                                    oldsecinfo[o].s_refcnt;

                                /*
                                 * Delete the old export flavor
                                 * reference.  The initial reference
                                 * was created during srv_secinfo_add,
                                 * and the count is decremented below
                                 * to account for the initial reference.
                                 */
                                if (SEC_REF_EXPORTED(&oldsecinfo[o]))
                                        curdata->ex_secinfo[c].s_refcnt--;

                                SECREF_TRACE(curdata->ex_path,
                                    "reshare_xfer_common_child_refs",
                                    curdata->ex_secinfo[c].s_secinfo.sc_nfsnum,
                                    curdata->ex_secinfo[c].s_refcnt);

                                ASSERT(curdata->ex_secinfo[c].s_refcnt >= 0);

                                tcnt--;
                                break;
                        }
                }
        }

        if (tcnt == ccnt)
                return; /* no more transfer to do */

        /*
         * oldsecinfo has flavors referenced by its children that are not
         * in the current (new) export flavor list.  Add these flavors.
         */
        msec = kmem_zalloc(tcnt * sizeof (struct secinfo), KM_SLEEP);

        /* move current secinfo list data to the new list */
        for (c = 0; c < ccnt; c++)
                msec[c] = curdata->ex_secinfo[c];

        /*
         * Add the flavor that's not in the new export, but still
         * referenced by its children.
         */
        mcnt = ccnt;
        for (o = 0; o < ocnt; o++) {
                if (! SEC_REF_SELF(&oldsecinfo[o])) {
                        for (c = 0; c < ccnt; c++) {
                                if (oldsecinfo[o].s_secinfo.sc_nfsnum ==
                                    curdata->ex_secinfo[c].s_secinfo.sc_nfsnum)
                                        break;
                        }

                        /*
                         * This is the one. Add it. Decrement the ref count
                         * by 1 if the flavor is an explicitly shared flavor
                         * for the oldsecinfo export node.
                         */
                        if (c == ccnt) {
                                srv_secinfo_copy(&oldsecinfo[o], &msec[mcnt]);
                                if (SEC_REF_EXPORTED(&oldsecinfo[o]))
                                        msec[mcnt].s_refcnt--;

                                SECREF_TRACE(curdata,
                                    "reshare_xfer_implicit_child_refs",
                                    msec[mcnt].s_secinfo.sc_nfsnum,
                                    msec[mcnt].s_refcnt);

                                ASSERT(msec[mcnt].s_refcnt >= 0);
                                mcnt++;
                        }
                }
        }

        ASSERT(mcnt == tcnt);
        /*
         * Done. Update curdata, free the existing secinfo list in
         * curdata and set the new value.
         */
        if (ccnt > 0)
                kmem_free(curdata->ex_secinfo, ccnt * sizeof (struct secinfo));
        curdata->ex_seccnt = tcnt;
        curdata->ex_secinfo = msec;
}

/*
 * When unsharing an old export node and the old node becomes a pseudo node,
 * if there is more than 1 export reference to an old flavor (i.e. some of
 * its children shared with this flavor), this flavor information needs to
 * be transferred to the new shared node.
 *
 * This routine is used under the protection of exported_lock (RW_WRITER).
 */
void
srv_secinfo_exp2pseu(exportdata_t *curdata, exportdata_t *olddata)
{
        int ocnt, o;            /* sec count in transfer data - trandata */
        int tcnt, mcnt;         /* total sec count after transfer */
        struct secinfo *msec;   /* merged secinfo list */

        ASSERT(curdata->ex_flags & EX_PSEUDO);
        ASSERT(curdata->ex_seccnt == 0);

        ocnt = olddata->ex_seccnt;

        /*
         * If the olddata has flavors with more than 1 reference count,
         * transfer the information to the curdata.
         */
        tcnt = ocnt;

        for (o = 0; o < ocnt; o++) {
                if (SEC_REF_SELF(&olddata->ex_secinfo[o]))
                        tcnt--;
        }

        if (tcnt == 0)
                return; /* no transfer to do */

        msec = kmem_zalloc(tcnt * sizeof (struct secinfo), KM_SLEEP);

        mcnt = 0;
        for (o = 0; o < ocnt; o++) {
                if (! SEC_REF_SELF(&olddata->ex_secinfo[o])) {

                        /*
                         * Decrement the reference count by 1 if the flavor is
                         * an explicitly shared flavor for the olddata export
                         * node.
                         */
                        srv_secinfo_copy(&olddata->ex_secinfo[o], &msec[mcnt]);
                        msec[mcnt].s_flags = M_RO;
                        if (SEC_REF_EXPORTED(&olddata->ex_secinfo[o]))
                                msec[mcnt].s_refcnt--;

                        SECREF_TRACE(curdata, "unshare_morph_pseudo",
                            msec[mcnt].s_secinfo.sc_nfsnum,
                            msec[mcnt].s_refcnt);

                        ASSERT(msec[mcnt].s_refcnt >= 0);
                        mcnt++;
                }
        }

        ASSERT(mcnt == tcnt);
        /*
         * Done. Update curdata.
         * Free up the existing secinfo list in curdata and
         * set the new value.
         */
        curdata->ex_seccnt = tcnt;
        curdata->ex_secinfo = msec;
}

/*
 * Find for given treenode the exportinfo which has its
 * exp_visible linked on its exi_visible list.
 *
 * Note: We could add new pointer either to treenode or
 * to exp_visible, which will point there directly.
 * This would buy some speed for some memory.
 */
exportinfo_t *
vis2exi(treenode_t *tnode)
{
        exportinfo_t *exi_ret = NULL;

        for (;;) {
                tnode = tnode->tree_parent;
                if (TREE_ROOT(tnode)) {
                        exi_ret = tnode->tree_exi;
                        break;
                }
        }

        ASSERT(exi_ret); /* Every visible should have its home exportinfo */
        return (exi_ret);
}

/*
 * For NFS V4.
 * Add or remove the newly exported or unexported security flavors of the
 * given exportinfo from its ancestors upto the system root.
 */
void
srv_secinfo_treeclimb(exportinfo_t *exip, secinfo_t *sec, int seccnt,
    bool_t isadd)
{
        treenode_t *tnode = exip->exi_tree;

        ASSERT(RW_WRITE_HELD(&exported_lock));
        ASSERT(tnode != NULL);

        if (seccnt == 0)
                return;

        /*
         * If flavors are being added and the new export root isn't
         * also VROOT, its implicitly allowed flavors are inherited from
         * its pseudonode.
         * Note - for VROOT exports the implicitly allowed flavors were
         * transferred from the PSEUDO export in exportfs()
         */
        if (isadd && !(exip->exi_vp->v_flag & VROOT) &&
            tnode->tree_vis->vis_seccnt > 0) {
                srv_secinfo_add(&exip->exi_export.ex_secinfo,
                    &exip->exi_export.ex_seccnt, tnode->tree_vis->vis_secinfo,
                    tnode->tree_vis->vis_seccnt, FALSE);
        }

        /*
         * Move to parent node and propagate sec flavor
         * to exportinfo and to visible structures.
         */
        tnode = tnode->tree_parent;

        while (tnode != NULL) {

                /* If there is exportinfo, update it */
                if (tnode->tree_exi != NULL) {
                        secinfo_t **pxsec =
                            &tnode->tree_exi->exi_export.ex_secinfo;
                        int *pxcnt = &tnode->tree_exi->exi_export.ex_seccnt;
                        int is_pseudo = PSEUDO(tnode->tree_exi);
                        if (isadd)
                                srv_secinfo_add(pxsec, pxcnt, sec, seccnt,
                                    is_pseudo);
                        else
                                srv_secinfo_remove(pxsec, pxcnt, sec, seccnt);
                }

                /* Update every visible - only root node has no visible */
                if (tnode->tree_vis != NULL) {
                        secinfo_t **pxsec = &tnode->tree_vis->vis_secinfo;
                        int *pxcnt = &tnode->tree_vis->vis_seccnt;
                        if (isadd)
                                srv_secinfo_add(pxsec, pxcnt, sec, seccnt,
                                    FALSE);
                        else
                                srv_secinfo_remove(pxsec, pxcnt, sec, seccnt);
                }
                tnode = tnode->tree_parent;
        }
}

/* hash_name is a text substitution for either fid_hash or path_hash */
#define exp_hash_unlink(exi, hash_name) \
        if (*(exi)->hash_name.bckt == (exi)) \
                *(exi)->hash_name.bckt = (exi)->hash_name.next; \
        if ((exi)->hash_name.prev) \
                (exi)->hash_name.prev->hash_name.next = (exi)->hash_name.next; \
        if ((exi)->hash_name.next) \
                (exi)->hash_name.next->hash_name.prev = (exi)->hash_name.prev; \
        (exi)->hash_name.bckt = NULL;

#define exp_hash_link(exi, hash_name, bucket) \
        (exi)->hash_name.bckt = (bucket); \
        (exi)->hash_name.prev = NULL; \
        (exi)->hash_name.next = *(bucket); \
        if ((exi)->hash_name.next) \
                (exi)->hash_name.next->hash_name.prev = (exi); \
        *(bucket) = (exi);

void
export_link(exportinfo_t *exi)
{
        exportinfo_t **bckt;

        bckt = &exptable[exptablehash(&exi->exi_fsid, &exi->exi_fid)];
        exp_hash_link(exi, fid_hash, bckt);

        bckt = &exptable_path_hash[pkp_tab_hash(exi->exi_export.ex_path,
            strlen(exi->exi_export.ex_path))];
        exp_hash_link(exi, path_hash, bckt);
}

/*
 * Initialization routine for export routines. Should only be called once.
 */
int
nfs_exportinit(void)
{
        int error;
        int i;

        rw_init(&exported_lock, NULL, RW_DEFAULT, NULL);

        /*
         * Allocate the place holder for the public file handle, which
         * is all zeroes. It is initially set to the root filesystem.
         */
        exi_root = kmem_zalloc(sizeof (*exi_root), KM_SLEEP);
        exi_public = exi_root;

        exi_root->exi_export.ex_flags = EX_PUBLIC;
        exi_root->exi_export.ex_pathlen = 1;    /* length of "/" */
        exi_root->exi_export.ex_path =
            kmem_alloc(exi_root->exi_export.ex_pathlen + 1, KM_SLEEP);
        exi_root->exi_export.ex_path[0] = '/';
        exi_root->exi_export.ex_path[1] = '\0';

        exi_root->exi_count = 1;
        mutex_init(&exi_root->exi_lock, NULL, MUTEX_DEFAULT, NULL);

        exi_root->exi_vp = rootdir;
        exi_rootfid.fid_len = MAXFIDSZ;
        error = vop_fid_pseudo(exi_root->exi_vp, &exi_rootfid);
        if (error) {
                mutex_destroy(&exi_root->exi_lock);
                kmem_free(exi_root, sizeof (*exi_root));
                return (error);
        }

        /*
         * Initialize auth cache and auth cache lock
         */
        for (i = 0; i < AUTH_TABLESIZE; i++) {
                exi_root->exi_cache[i] = kmem_alloc(sizeof (avl_tree_t),
                    KM_SLEEP);
                avl_create(exi_root->exi_cache[i], nfsauth_cache_clnt_compar,
                    sizeof (struct auth_cache_clnt),
                    offsetof(struct auth_cache_clnt, authc_link));
        }
        rw_init(&exi_root->exi_cache_lock, NULL, RW_DEFAULT, NULL);

        /* setup the fhandle template */
        exi_root->exi_fh.fh_fsid = rootdir->v_vfsp->vfs_fsid;
        exi_root->exi_fh.fh_xlen = exi_rootfid.fid_len;
        bcopy(exi_rootfid.fid_data, exi_root->exi_fh.fh_xdata,
            exi_rootfid.fid_len);
        exi_root->exi_fh.fh_len = sizeof (exi_root->exi_fh.fh_data);

        /*
         * Publish the exportinfo in the hash table
         */
        export_link(exi_root);

        nfslog_init();
        ns_root = NULL;

        return (0);
}

/*
 * Finalization routine for export routines. Called to cleanup previously
 * initialization work when the NFS server module could not be loaded correctly.
 */
void
nfs_exportfini(void)
{
        int i;

        /*
         * Deallocate the place holder for the public file handle.
         */
        srv_secinfo_list_free(exi_root->exi_export.ex_secinfo,
            exi_root->exi_export.ex_seccnt);
        mutex_destroy(&exi_root->exi_lock);
        rw_destroy(&exi_root->exi_cache_lock);
        for (i = 0; i < AUTH_TABLESIZE; i++) {
                avl_destroy(exi_root->exi_cache[i]);
                kmem_free(exi_root->exi_cache[i], sizeof (avl_tree_t));
        }
        kmem_free(exi_root, sizeof (*exi_root));

        rw_destroy(&exported_lock);
}

/*
 *  Check if 2 gss mechanism identifiers are the same.
 *
 *  return FALSE if not the same.
 *  return TRUE if the same.
 */
static bool_t
nfs_mech_equal(rpc_gss_OID mech1, rpc_gss_OID mech2)
{
        if ((mech1->length == 0) && (mech2->length == 0))
                return (TRUE);

        if (mech1->length != mech2->length)
                return (FALSE);

        return (bcmp(mech1->elements, mech2->elements, mech1->length) == 0);
}

/*
 *  This routine is used by rpc to map rpc security number
 *  to nfs specific security flavor number.
 *
 *  The gss callback prototype is
 *  callback(struct svc_req *, gss_cred_id_t *, gss_ctx_id_t *,
 *                              rpc_gss_lock_t *, void **),
 *  since nfs does not use the gss_cred_id_t/gss_ctx_id_t arguments
 *  we cast them to void.
 */
/*ARGSUSED*/
bool_t
rfs_gsscallback(struct svc_req *req, gss_cred_id_t deleg, void *gss_context,
    rpc_gss_lock_t *lock, void **cookie)
{
        int i, j;
        rpc_gss_rawcred_t *raw_cred;
        struct exportinfo *exi;

        /*
         * We don't deal with delegated credentials.
         */
        if (deleg != GSS_C_NO_CREDENTIAL)
                return (FALSE);

        raw_cred = lock->raw_cred;
        *cookie = NULL;

        rw_enter(&exported_lock, RW_READER);
        for (i = 0; i < EXPTABLESIZE; i++) {
                exi = exptable[i];
                while (exi) {
                        if (exi->exi_export.ex_seccnt > 0) {
                                struct secinfo *secp;
                                seconfig_t *se;
                                int seccnt;

                                secp = exi->exi_export.ex_secinfo;
                                seccnt = exi->exi_export.ex_seccnt;
                                for (j = 0; j < seccnt; j++) {
                                        /*
                                         *  If there is a map of the triplet
                                         *  (mechanism, service, qop) between
                                         *  raw_cred and the exported flavor,
                                         *  get the psudo flavor number.
                                         *  Also qop should not be NULL, it
                                         *  should be "default" or something
                                         *  else.
                                         */
                                        se = &secp[j].s_secinfo;
                                        if ((se->sc_rpcnum == RPCSEC_GSS) &&

                                            (nfs_mech_equal(
                                            se->sc_gss_mech_type,
                                            raw_cred->mechanism)) &&

                                            (se->sc_service ==
                                            raw_cred->service) &&
                                            (raw_cred->qop == se->sc_qop)) {

                                                *cookie = (void *)(uintptr_t)
                                                    se->sc_nfsnum;
                                                goto done;
                                        }
                                }
                        }
                        exi = exi->fid_hash.next;
                }
        }
done:
        rw_exit(&exported_lock);

        /*
         * If no nfs pseudo number mapping can be found in the export
         * table, assign the nfsflavor to NFS_FLAVOR_NOMAP. In V4, we may
         * recover the flavor mismatch from NFS layer (NFS4ERR_WRONGSEC).
         *
         * For example:
         *      server first shares with krb5i;
         *      client mounts with krb5i;
         *      server re-shares with krb5p;
         *      client tries with krb5i, but no mapping can be found;
         *      rpcsec_gss module calls this routine to do the mapping,
         *              if this routine fails, request is rejected from
         *              the rpc layer.
         *      What we need is to let the nfs layer rejects the request.
         *      For V4, we can reject with NFS4ERR_WRONGSEC and the client
         *      may recover from it by getting the new flavor via SECINFO.
         *
         * nfs pseudo number for RPCSEC_GSS mapping (see nfssec.conf)
         * is owned by IANA (see RFC 2623).
         *
         * XXX NFS_FLAVOR_NOMAP is defined in Solaris to work around
         * the implementation issue. This number should not overlap with
         * any new IANA defined pseudo flavor numbers.
         */
        if (*cookie == NULL)
                *cookie = (void *)NFS_FLAVOR_NOMAP;

        lock->locked = TRUE;

        return (TRUE);
}


/*
 * Exportfs system call; credentials should be checked before
 * calling this function.
 */
int
exportfs(struct exportfs_args *args, model_t model, cred_t *cr)
{
        vnode_t *vp;
        vnode_t *dvp;
        struct exportdata *kex;
        struct exportinfo *exi = NULL;
        struct exportinfo *ex, *ex1, *ex2;
        fid_t fid;
        fsid_t fsid;
        int error;
        size_t allocsize;
        struct secinfo *sp;
        struct secinfo *exs;
        rpc_gss_callback_t cb;
        char *pathbuf;
        char *log_buffer;
        char *tagbuf;
        int callback;
        int allocd_seccnt;
        STRUCT_HANDLE(exportfs_args, uap);
        STRUCT_DECL(exportdata, uexi);
        struct secinfo newsec[MAX_FLAVORS];
        int newcnt;
        struct secinfo oldsec[MAX_FLAVORS];
        int oldcnt;
        int i;
        struct pathname lookpn;

        STRUCT_SET_HANDLE(uap, model, args);

        /* Read in pathname from userspace */
        if (error = pn_get(STRUCT_FGETP(uap, dname), UIO_USERSPACE, &lookpn))
                return (error);

        /* Walk the export list looking for that pathname */
        rw_enter(&exported_lock, RW_READER);
        DTRACE_PROBE(nfss__i__exported_lock1_start);
        for (ex1 = exptable_path_hash[pkp_tab_hash(lookpn.pn_path,
            strlen(lookpn.pn_path))]; ex1; ex1 = ex1->path_hash.next) {
                if (ex1 != exi_root && 0 ==
                    strcmp(ex1->exi_export.ex_path, lookpn.pn_path)) {
                        exi_hold(ex1);
                        break;
                }
        }
        DTRACE_PROBE(nfss__i__exported_lock1_stop);
        rw_exit(&exported_lock);

        /* Is this an unshare? */
        if (STRUCT_FGETP(uap, uex) == NULL) {
                pn_free(&lookpn);
                if (ex1 == NULL)
                        return (EINVAL);
                error = unexport(ex1);
                exi_rele(ex1);
                return (error);
        }

        /* It is a share or a re-share */
        error = lookupname(STRUCT_FGETP(uap, dname), UIO_USERSPACE,
            FOLLOW, &dvp, &vp);
        if (error == EINVAL) {
                /*
                 * if fname resolves to / we get EINVAL error
                 * since we wanted the parent vnode. Try again
                 * with NULL dvp.
                 */
                error = lookupname(STRUCT_FGETP(uap, dname), UIO_USERSPACE,
                    FOLLOW, NULL, &vp);
                dvp = NULL;
        }
        if (!error && vp == NULL) {
                /* Last component of fname not found */
                if (dvp != NULL)
                        VN_RELE(dvp);
                error = ENOENT;
        }
        if (error) {
                pn_free(&lookpn);
                if (ex1)
                        exi_rele(ex1);
                return (error);
        }

        /*
         * 'vp' may be an AUTOFS node, so we perform a
         * fop_access() to trigger the mount of the
         * intended filesystem, so we can share the intended
         * filesystem instead of the AUTOFS filesystem.
         */
        (void) fop_access(vp, 0, 0, cr, NULL);

        /*
         * We're interested in the top most filesystem.
         * This is specially important when uap->dname is a trigger
         * AUTOFS node, since we're really interested in sharing the
         * filesystem AUTOFS mounted as result of the fop_access()
         * call not the AUTOFS node itself.
         */
        if (vn_mountedvfs(vp) != NULL) {
                if (error = traverse(&vp)) {
                        VN_RELE(vp);
                        if (dvp != NULL)
                                VN_RELE(dvp);
                        pn_free(&lookpn);
                        if (ex1)
                                exi_rele(ex1);
                        return (error);
                }
        }

        /* Do not allow sharing another vnode for already shared path */
        if (ex1 && !PSEUDO(ex1) && !VN_CMP(ex1->exi_vp, vp)) {
                VN_RELE(vp);
                if (dvp != NULL)
                        VN_RELE(dvp);
                pn_free(&lookpn);
                exi_rele(ex1);
                return (EEXIST);
        }
        if (ex1)
                exi_rele(ex1);

        /*
         * Get the vfs id
         */
        bzero(&fid, sizeof (fid));
        fid.fid_len = MAXFIDSZ;
        error = fop_fid(vp, &fid, NULL);
        fsid = vp->v_vfsp->vfs_fsid;

        if (error) {
                VN_RELE(vp);
                if (dvp != NULL)
                        VN_RELE(dvp);
                /*
                 * If fop_fid returns ENOSPC then the fid supplied
                 * is too small.  For now we simply return EREMOTE.
                 */
                if (error == ENOSPC)
                        error = EREMOTE;
                pn_free(&lookpn);
                return (error);
        }

        /*
         * Do not allow re-sharing a shared vnode under a different path
         * PSEUDO export has ex_path fabricated, e.g. "/tmp (pseudo)", skip it.
         */
        rw_enter(&exported_lock, RW_READER);
        DTRACE_PROBE(nfss__i__exported_lock2_start);
        for (ex2 = exptable[exptablehash(&fsid, &fid)]; ex2;
            ex2 = ex2->fid_hash.next) {
                if (ex2 != exi_root && !PSEUDO(ex2) &&
                    VN_CMP(ex2->exi_vp, vp) &&
                    strcmp(ex2->exi_export.ex_path, lookpn.pn_path) != 0) {
                        DTRACE_PROBE(nfss__i__exported_lock2_stop);
                        rw_exit(&exported_lock);
                        VN_RELE(vp);
                        if (dvp != NULL)
                                VN_RELE(dvp);
                        pn_free(&lookpn);
                        return (EEXIST);
                }
        }
        DTRACE_PROBE(nfss__i__exported_lock2_stop);
        rw_exit(&exported_lock);
        pn_free(&lookpn);

        exi = kmem_zalloc(sizeof (*exi), KM_SLEEP);
        exi->exi_fsid = fsid;
        exi->exi_fid = fid;
        exi->exi_vp = vp;
        exi->exi_count = 1;
        exi->exi_volatile_dev = (vfssw[vp->v_vfsp->vfs_fstype].vsw_flag &
            VSW_VOLATILEDEV) ? 1 : 0;
        mutex_init(&exi->exi_lock, NULL, MUTEX_DEFAULT, NULL);
        exi->exi_dvp = dvp;

        /*
         * Initialize auth cache and auth cache lock
         */
        for (i = 0; i < AUTH_TABLESIZE; i++) {
                exi->exi_cache[i] = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
                avl_create(exi->exi_cache[i], nfsauth_cache_clnt_compar,
                    sizeof (struct auth_cache_clnt),
                    offsetof(struct auth_cache_clnt, authc_link));
        }
        rw_init(&exi->exi_cache_lock, NULL, RW_DEFAULT, NULL);

        /*
         * Build up the template fhandle
         */
        exi->exi_fh.fh_fsid = fsid;
        if (exi->exi_fid.fid_len > sizeof (exi->exi_fh.fh_xdata)) {
                error = EREMOTE;
                goto out1;
        }
        exi->exi_fh.fh_xlen = exi->exi_fid.fid_len;
        bcopy(exi->exi_fid.fid_data, exi->exi_fh.fh_xdata,
            exi->exi_fid.fid_len);

        exi->exi_fh.fh_len = sizeof (exi->exi_fh.fh_data);

        kex = &exi->exi_export;

        /*
         * Load in everything, and do sanity checking
         */
        STRUCT_INIT(uexi, model);
        if (copyin(STRUCT_FGETP(uap, uex), STRUCT_BUF(uexi),
            STRUCT_SIZE(uexi))) {
                error = EFAULT;
                goto out1;
        }

        kex->ex_version = STRUCT_FGET(uexi, ex_version);
        if (kex->ex_version != EX_CURRENT_VERSION) {
                error = EINVAL;
                cmn_err(CE_WARN,
                    "NFS: exportfs requires export struct version 2 - got %d\n",
                    kex->ex_version);
                goto out1;
        }

        /*
         * Must have at least one security entry
         */
        kex->ex_seccnt = STRUCT_FGET(uexi, ex_seccnt);
        if (kex->ex_seccnt < 1) {
                error = EINVAL;
                goto out1;
        }

        kex->ex_path = STRUCT_FGETP(uexi, ex_path);
        kex->ex_pathlen = STRUCT_FGET(uexi, ex_pathlen);
        kex->ex_flags = STRUCT_FGET(uexi, ex_flags);
        kex->ex_anon = STRUCT_FGET(uexi, ex_anon);
        kex->ex_secinfo = STRUCT_FGETP(uexi, ex_secinfo);
        kex->ex_index = STRUCT_FGETP(uexi, ex_index);
        kex->ex_log_buffer = STRUCT_FGETP(uexi, ex_log_buffer);
        kex->ex_log_bufferlen = STRUCT_FGET(uexi, ex_log_bufferlen);
        kex->ex_tag = STRUCT_FGETP(uexi, ex_tag);
        kex->ex_taglen = STRUCT_FGET(uexi, ex_taglen);

        /*
         * Copy the exported pathname into
         * an appropriately sized buffer.
         */
        pathbuf = kmem_alloc(MAXPATHLEN, KM_SLEEP);
        if (copyinstr(kex->ex_path, pathbuf, MAXPATHLEN, &kex->ex_pathlen)) {
                kmem_free(pathbuf, MAXPATHLEN);
                error = EFAULT;
                goto out1;
        }
        kex->ex_path = kmem_alloc(kex->ex_pathlen + 1, KM_SLEEP);
        bcopy(pathbuf, kex->ex_path, kex->ex_pathlen);
        kex->ex_path[kex->ex_pathlen] = '\0';
        kmem_free(pathbuf, MAXPATHLEN);

        /*
         * Get the path to the logging buffer and the tag
         */
        if (kex->ex_flags & EX_LOG) {
                log_buffer = kmem_alloc(MAXPATHLEN, KM_SLEEP);
                if (copyinstr(kex->ex_log_buffer, log_buffer, MAXPATHLEN,
                    &kex->ex_log_bufferlen)) {
                        kmem_free(log_buffer, MAXPATHLEN);
                        error = EFAULT;
                        goto out2;
                }
                kex->ex_log_buffer =
                    kmem_alloc(kex->ex_log_bufferlen + 1, KM_SLEEP);
                bcopy(log_buffer, kex->ex_log_buffer, kex->ex_log_bufferlen);
                kex->ex_log_buffer[kex->ex_log_bufferlen] = '\0';
                kmem_free(log_buffer, MAXPATHLEN);

                tagbuf = kmem_alloc(MAXPATHLEN, KM_SLEEP);
                if (copyinstr(kex->ex_tag, tagbuf, MAXPATHLEN,
                    &kex->ex_taglen)) {
                        kmem_free(tagbuf, MAXPATHLEN);
                        error = EFAULT;
                        goto out3;
                }
                kex->ex_tag = kmem_alloc(kex->ex_taglen + 1, KM_SLEEP);
                bcopy(tagbuf, kex->ex_tag, kex->ex_taglen);
                kex->ex_tag[kex->ex_taglen] = '\0';
                kmem_free(tagbuf, MAXPATHLEN);
        }

        /*
         * Load the security information for each flavor
         */
        allocsize = kex->ex_seccnt * SIZEOF_STRUCT(secinfo, model);
        sp = kmem_zalloc(allocsize, KM_SLEEP);
        if (copyin(kex->ex_secinfo, sp, allocsize)) {
                kmem_free(sp, allocsize);
                error = EFAULT;
                goto out4;
        }

        /*
         * All of these nested structures need to be converted to
         * the kernel native format.
         */
        if (model != DATAMODEL_NATIVE) {
                size_t allocsize2;
                struct secinfo *sp2;

                allocsize2 = kex->ex_seccnt * sizeof (struct secinfo);
                sp2 = kmem_zalloc(allocsize2, KM_SLEEP);

                for (i = 0; i < kex->ex_seccnt; i++) {
                        STRUCT_HANDLE(secinfo, usi);

                        STRUCT_SET_HANDLE(usi, model,
                            (struct secinfo *)((caddr_t)sp +
                            (i * SIZEOF_STRUCT(secinfo, model))));
                        bcopy(STRUCT_FGET(usi, s_secinfo.sc_name),
                            sp2[i].s_secinfo.sc_name, MAX_NAME_LEN);
                        sp2[i].s_secinfo.sc_nfsnum =
                            STRUCT_FGET(usi, s_secinfo.sc_nfsnum);
                        sp2[i].s_secinfo.sc_rpcnum =
                            STRUCT_FGET(usi, s_secinfo.sc_rpcnum);
                        bcopy(STRUCT_FGET(usi, s_secinfo.sc_gss_mech),
                            sp2[i].s_secinfo.sc_gss_mech, MAX_NAME_LEN);
                        sp2[i].s_secinfo.sc_gss_mech_type =
                            STRUCT_FGETP(usi, s_secinfo.sc_gss_mech_type);
                        sp2[i].s_secinfo.sc_qop =
                            STRUCT_FGET(usi, s_secinfo.sc_qop);
                        sp2[i].s_secinfo.sc_service =
                            STRUCT_FGET(usi, s_secinfo.sc_service);

                        sp2[i].s_flags = STRUCT_FGET(usi, s_flags);
                        sp2[i].s_window = STRUCT_FGET(usi, s_window);
                        sp2[i].s_rootid = STRUCT_FGET(usi, s_rootid);
                        sp2[i].s_rootcnt = STRUCT_FGET(usi, s_rootcnt);
                        sp2[i].s_rootnames = STRUCT_FGETP(usi, s_rootnames);
                }
                kmem_free(sp, allocsize);
                sp = sp2;
                allocsize = allocsize2;
        }

        kex->ex_secinfo = sp;

        /*
         * And now copy rootnames for each individual secinfo.
         */
        callback = 0;
        allocd_seccnt = 0;
        while (allocd_seccnt < kex->ex_seccnt) {

                exs = &sp[allocd_seccnt];
                if (exs->s_rootcnt > 0) {
                        if (!sec_svc_loadrootnames(exs->s_secinfo.sc_rpcnum,
                            exs->s_rootcnt, &exs->s_rootnames, model)) {
                                error = EFAULT;
                                goto out5;
                        }
                }

                if (exs->s_secinfo.sc_rpcnum == RPCSEC_GSS) {
                        rpc_gss_OID mech_tmp;
                        STRUCT_DECL(rpc_gss_OID_s, umech_tmp);
                        caddr_t elements_tmp;

                        /* Copyin mechanism type */
                        STRUCT_INIT(umech_tmp, model);
                        mech_tmp = kmem_alloc(sizeof (*mech_tmp), KM_SLEEP);
                        if (copyin(exs->s_secinfo.sc_gss_mech_type,
                            STRUCT_BUF(umech_tmp), STRUCT_SIZE(umech_tmp))) {
                                kmem_free(mech_tmp, sizeof (*mech_tmp));
                                error = EFAULT;
                                goto out5;
                        }
                        mech_tmp->length = STRUCT_FGET(umech_tmp, length);
                        mech_tmp->elements = STRUCT_FGETP(umech_tmp, elements);

                        elements_tmp = kmem_alloc(mech_tmp->length, KM_SLEEP);
                        if (copyin(mech_tmp->elements, elements_tmp,
                            mech_tmp->length)) {
                                kmem_free(elements_tmp, mech_tmp->length);
                                kmem_free(mech_tmp, sizeof (*mech_tmp));
                                error = EFAULT;
                                goto out5;
                        }
                        mech_tmp->elements = elements_tmp;
                        exs->s_secinfo.sc_gss_mech_type = mech_tmp;
                        allocd_seccnt++;

                        callback = 1;
                } else
                        allocd_seccnt++;
        }

        /*
         * Init the secinfo reference count and mark these flavors
         * explicitly exported flavors.
         */
        for (i = 0; i < kex->ex_seccnt; i++) {
                kex->ex_secinfo[i].s_flags |= M_4SEC_EXPORTED;
                kex->ex_secinfo[i].s_refcnt = 1;
        }

        /*
         *  Set up rpcsec_gss callback routine entry if any.
         */
        if (callback) {
                cb.callback = rfs_gsscallback;
                cb.program = NFS_ACL_PROGRAM;
                for (cb.version = NFS_ACL_VERSMIN;
                    cb.version <= NFS_ACL_VERSMAX; cb.version++) {
                        (void) sec_svc_control(RPC_SVC_SET_GSS_CALLBACK,
                            (void *)&cb);
                }

                cb.program = NFS_PROGRAM;
                for (cb.version = NFS_VERSMIN;
                    cb.version <= NFS_VERSMAX; cb.version++) {
                        (void) sec_svc_control(RPC_SVC_SET_GSS_CALLBACK,
                            (void *)&cb);
                }
        }

        /*
         * Check the index flag. Do this here to avoid holding the
         * lock while dealing with the index option (as we do with
         * the public option).
         */
        if (kex->ex_flags & EX_INDEX) {
                if (!kex->ex_index) {   /* sanity check */
                        error = EINVAL;
                        goto out5;
                }
                if (error = loadindex(kex))
                        goto out5;
        }

        if (kex->ex_flags & EX_LOG) {
                if (error = nfslog_setup(exi))
                        goto out6;
        }

        /*
         * Insert the new entry at the front of the export list
         */
        rw_enter(&exported_lock, RW_WRITER);
        DTRACE_PROBE(nfss__i__exported_lock3_start);

        export_link(exi);

        /*
         * Check the rest of the list for an old entry for the fs.
         * If one is found then unlink it, wait until this is the
         * only reference and then free it.
         */
        for (ex = exi->fid_hash.next; ex != NULL; ex = ex->fid_hash.next) {
                if (ex != exi_root && VN_CMP(ex->exi_vp, vp)) {
                        export_unlink(ex);
                        break;
                }
        }

        /*
         * If the public filehandle is pointing at the
         * old entry, then point it back at the root.
         */
        if (ex != NULL && ex == exi_public)
                exi_public = exi_root;

        /*
         * If the public flag is on, make the global exi_public
         * point to this entry and turn off the public bit so that
         * we can distinguish it from the place holder export.
         */
        if (kex->ex_flags & EX_PUBLIC) {
                exi_public = exi;
                kex->ex_flags &= ~EX_PUBLIC;
        }

#ifdef VOLATILE_FH_TEST
        /*
         * Set up the volatile_id value if volatile on share.
         * The list of volatile renamed filehandles is always destroyed,
         * if the fs was reshared.
         */
        if (kex->ex_flags & EX_VOLFH)
                exi->exi_volatile_id = gethrestime_sec();

        mutex_init(&exi->exi_vol_rename_lock, NULL, MUTEX_DEFAULT, NULL);
#endif /* VOLATILE_FH_TEST */

        /*
         * If this is a new export, then climb up
         * the tree and check if any pseudo exports
         * need to be created to provide a path for
         * NFS v4 clients.
         */
        if (ex == NULL) {
                error = treeclimb_export(exi);
                if (error)
                        goto out7;
        } else {
                /* If it's a re-export update namespace tree */
                exi->exi_tree = ex->exi_tree;
                exi->exi_tree->tree_exi = exi;

                /* Update the change timestamp */
                tree_update_change(exi->exi_tree, NULL);
        }

        /*
         * build a unique flavor list from the flavors specified
         * in the share cmd.  unique means that each flavor only
         * appears once in the secinfo list -- no duplicates allowed.
         */
        newcnt = build_seclist_nodups(&exi->exi_export, newsec, FALSE);

        srv_secinfo_treeclimb(exi, newsec, newcnt, TRUE);

        /*
         * If re-sharing an old export entry, update the secinfo data
         * depending on if the old entry is a pseudo node or not.
         */
        if (ex != NULL) {
                oldcnt = build_seclist_nodups(&ex->exi_export, oldsec, FALSE);
                if (PSEUDO(ex)) {
                        /*
                         * The dir being shared is a pseudo export root (which
                         * will be transformed into a real export root).  The
                         * flavor(s) of the new share were propagated to the
                         * ancestors by srv_secinfo_treeclimb() above.  Now
                         * transfer the implicit flavor refs from the old
                         * pseudo exprot root to the new (real) export root.
                         */
                        srv_secinfo_add(&exi->exi_export.ex_secinfo,
                            &exi->exi_export.ex_seccnt, oldsec, oldcnt, TRUE);
                } else {
                        /*
                         * First transfer implicit flavor refs to new export.
                         * Remove old flavor refs last.
                         */
                        srv_secinfo_exp2exp(&exi->exi_export, oldsec, oldcnt);
                        srv_secinfo_treeclimb(ex, oldsec, oldcnt, FALSE);
                }
        }

        /*
         * If it's a re-export and the old entry has a pseudonode list,
         * transfer it to the new export.
         */
        if (ex != NULL && (ex->exi_visible != NULL)) {
                exi->exi_visible = ex->exi_visible;
                ex->exi_visible = NULL;
        }

        DTRACE_PROBE(nfss__i__exported_lock3_stop);
        rw_exit(&exported_lock);

        if (exi_public == exi || kex->ex_flags & EX_LOG) {
                /*
                 * Log share operation to this buffer only.
                 */
                nfslog_share_record(exi, cr);
        }

        if (ex != NULL)
                exi_rele(ex);

        return (0);

out7:
        /* Unlink the new export in exptable. */
        export_unlink(exi);
        DTRACE_PROBE(nfss__i__exported_lock3_stop);
        rw_exit(&exported_lock);
out6:
        if (kex->ex_flags & EX_INDEX)
                kmem_free(kex->ex_index, strlen(kex->ex_index) + 1);
out5:
        /* free partially completed allocation */
        while (--allocd_seccnt >= 0) {
                exs = &kex->ex_secinfo[allocd_seccnt];
                srv_secinfo_entry_free(exs);
        }

        if (kex->ex_secinfo) {
                kmem_free(kex->ex_secinfo,
                    kex->ex_seccnt * sizeof (struct secinfo));
        }

out4:
        if ((kex->ex_flags & EX_LOG) && kex->ex_tag != NULL)
                kmem_free(kex->ex_tag, kex->ex_taglen + 1);
out3:
        if ((kex->ex_flags & EX_LOG) && kex->ex_log_buffer != NULL)
                kmem_free(kex->ex_log_buffer, kex->ex_log_bufferlen + 1);
out2:
        kmem_free(kex->ex_path, kex->ex_pathlen + 1);
out1:
        VN_RELE(vp);
        if (dvp != NULL)
                VN_RELE(dvp);
        mutex_destroy(&exi->exi_lock);
        rw_destroy(&exi->exi_cache_lock);
        for (i = 0; i < AUTH_TABLESIZE; i++) {
                avl_destroy(exi->exi_cache[i]);
                kmem_free(exi->exi_cache[i], sizeof (avl_tree_t));
        }

        kmem_free(exi, sizeof (*exi));

        return (error);
}

/*
 * Remove the exportinfo from the export list
 */
void
export_unlink(struct exportinfo *exi)
{
        ASSERT(RW_WRITE_HELD(&exported_lock));

        exp_hash_unlink(exi, fid_hash);
        exp_hash_unlink(exi, path_hash);
}

/*
 * Unexport an exported filesystem
 */
static int
unexport(struct exportinfo *exi)
{
        struct secinfo cursec[MAX_FLAVORS];
        int curcnt;

        rw_enter(&exported_lock, RW_WRITER);

        /* Check if exi is still linked in the export table */
        if (!EXP_LINKED(exi) || PSEUDO(exi)) {
                rw_exit(&exported_lock);
                return (EINVAL);
        }

        export_unlink(exi);

        /*
         * Remove security flavors before treeclimb_unexport() is called
         * because srv_secinfo_treeclimb needs the namespace tree
         */
        curcnt = build_seclist_nodups(&exi->exi_export, cursec, TRUE);

        srv_secinfo_treeclimb(exi, cursec, curcnt, FALSE);

        /*
         * If there's a visible list, then need to leave
         * a pseudo export here to retain the visible list
         * for paths to exports below.
         */
        if (exi->exi_visible != NULL) {
                struct exportinfo *newexi;

                newexi = pseudo_exportfs(exi->exi_vp, &exi->exi_fid,
                    exi->exi_visible, &exi->exi_export);
                exi->exi_visible = NULL;

                /* interconnect the existing treenode with the new exportinfo */
                newexi->exi_tree = exi->exi_tree;
                newexi->exi_tree->tree_exi = newexi;

                /* Update the change timestamp */
                tree_update_change(exi->exi_tree, NULL);
        } else {
                treeclimb_unexport(exi);
        }

        rw_exit(&exported_lock);

        /*
         * Need to call into the NFSv4 server and release all data
         * held on this particular export.  This is important since
         * the v4 server may be holding file locks or vnodes under
         * this export.
         */
        rfs4_clean_state_exi(exi);

        /*
         * Notify the lock manager that the filesystem is being
         * unexported.
         */
        lm_unexport(exi);

        /*
         * If this was a public export, restore
         * the public filehandle to the root.
         */
        if (exi == exi_public) {
                exi_public = exi_root;

                nfslog_share_record(exi_public, CRED());
        }

        if (exi->exi_export.ex_flags & EX_LOG) {
                nfslog_unshare_record(exi, CRED());
        }

        exi_rele(exi);
        return (0);
}

/*
 * Get file handle system call.
 * Takes file name and returns a file handle for it.
 * Credentials must be verified before calling.
 */
int
nfs_getfh(struct nfs_getfh_args *args, model_t model, cred_t *cr)
{
        nfs_fh3 fh;
        char buf[NFS3_MAXFHSIZE];
        char *logptr, logbuf[NFS3_MAXFHSIZE];
        int l = NFS3_MAXFHSIZE;
        vnode_t *vp;
        vnode_t *dvp;
        struct exportinfo *exi;
        int error;
        int vers;
        STRUCT_HANDLE(nfs_getfh_args, uap);


        STRUCT_SET_HANDLE(uap, model, args);

        error = lookupname(STRUCT_FGETP(uap, fname), UIO_USERSPACE,
            FOLLOW, &dvp, &vp);
        if (error == EINVAL) {
                /*
                 * if fname resolves to / we get EINVAL error
                 * since we wanted the parent vnode. Try again
                 * with NULL dvp.
                 */
                error = lookupname(STRUCT_FGETP(uap, fname), UIO_USERSPACE,
                    FOLLOW, NULL, &vp);
                dvp = NULL;
        }
        if (!error && vp == NULL) {
                /*
                 * Last component of fname not found
                 */
                if (dvp != NULL) {
                        VN_RELE(dvp);
                }
                error = ENOENT;
        }
        if (error)
                return (error);

        /*
         * 'vp' may be an AUTOFS node, so we perform a
         * fop_access() to trigger the mount of the
         * intended filesystem, so we can share the intended
         * filesystem instead of the AUTOFS filesystem.
         */
        (void) fop_access(vp, 0, 0, cr, NULL);

        /*
         * We're interested in the top most filesystem.
         * This is specially important when uap->dname is a trigger
         * AUTOFS node, since we're really interested in sharing the
         * filesystem AUTOFS mounted as result of the fop_access()
         * call not the AUTOFS node itself.
         */
        if (vn_mountedvfs(vp) != NULL) {
                if (error = traverse(&vp)) {
                        VN_RELE(vp);
                        if (dvp != NULL)
                                VN_RELE(dvp);
                        return (error);
                }
        }

        vers = STRUCT_FGET(uap, vers);
        exi = nfs_vptoexi(dvp, vp, cr, NULL, &error, FALSE);
        if (!error) {
                if (vers == NFS_VERSION) {
                        error = makefh((fhandle_t *)buf, vp, exi);
                        l = NFS_FHSIZE;
                        logptr = buf;
                } else if (vers == NFS_V3) {
                        int i, sz, pad;

                        error = makefh3(&fh, vp, exi);
                        l = RNDUP(fh.fh3_length);
                        if (!error && (l > sizeof (fhandle3_t)))
                                error = EREMOTE;
                        logptr = logbuf;
                        if (!error) {
                                i = 0;
                                sz = sizeof (fsid_t);
                                bcopy(&fh.fh3_fsid, &buf[i], sz);
                                i += sz;

                                /*
                                 * For backwards compatibility, the
                                 * fid length may be less than
                                 * NFS_FHMAXDATA, but it was always
                                 * encoded as NFS_FHMAXDATA bytes.
                                 */

                                sz = sizeof (ushort_t);
                                bcopy(&fh.fh3_len, &buf[i], sz);
                                i += sz;
                                bcopy(fh.fh3_data, &buf[i], fh.fh3_len);
                                i += fh.fh3_len;
                                pad = (NFS_FHMAXDATA - fh.fh3_len);
                                if (pad > 0) {
                                        bzero(&buf[i], pad);
                                        i += pad;
                                        l += pad;
                                }

                                sz = sizeof (ushort_t);
                                bcopy(&fh.fh3_xlen, &buf[i], sz);
                                i += sz;
                                bcopy(fh.fh3_xdata, &buf[i], fh.fh3_xlen);
                                i += fh.fh3_xlen;
                                pad = (NFS_FHMAXDATA - fh.fh3_xlen);
                                if (pad > 0) {
                                        bzero(&buf[i], pad);
                                        i += pad;
                                        l += pad;
                                }
                        }
                        /*
                         * If we need to do NFS logging, the filehandle
                         * must be downsized to 32 bytes.
                         */
                        if (!error && exi->exi_export.ex_flags & EX_LOG) {
                                i = 0;
                                sz = sizeof (fsid_t);
                                bcopy(&fh.fh3_fsid, &logbuf[i], sz);
                                i += sz;
                                sz = sizeof (ushort_t);
                                bcopy(&fh.fh3_len, &logbuf[i], sz);
                                i += sz;
                                sz = NFS_FHMAXDATA;
                                bcopy(fh.fh3_data, &logbuf[i], sz);
                                i += sz;
                                sz = sizeof (ushort_t);
                                bcopy(&fh.fh3_xlen, &logbuf[i], sz);
                                i += sz;
                                sz = NFS_FHMAXDATA;
                                bcopy(fh.fh3_xdata, &logbuf[i], sz);
                                i += sz;
                        }
                }
                if (!error && exi->exi_export.ex_flags & EX_LOG) {
                        nfslog_getfh(exi, (fhandle_t *)logptr,
                            STRUCT_FGETP(uap, fname), UIO_USERSPACE, cr);
                }
                exi_rele(exi);
                if (!error) {
                        if (copyout(&l, STRUCT_FGETP(uap, lenp), sizeof (int)))
                                error = EFAULT;
                        if (copyout(buf, STRUCT_FGETP(uap, fhp), l))
                                error = EFAULT;
                }
        }
        VN_RELE(vp);
        if (dvp != NULL) {
                VN_RELE(dvp);
        }
        return (error);
}

/*
 * Strategy: if vp is in the export list, then
 * return the associated file handle. Otherwise, ".."
 * once up the vp and try again, until the root of the
 * filesystem is reached.
 */
struct   exportinfo *
nfs_vptoexi(vnode_t *dvp, vnode_t *vp, cred_t *cr, int *walk,
    int *err, bool_t v4srv)
{
        fid_t fid;
        int error;
        struct exportinfo *exi;

        ASSERT(vp);
        VN_HOLD(vp);
        if (dvp != NULL) {
                VN_HOLD(dvp);
        }
        if (walk != NULL)
                *walk = 0;

        for (;;) {
                bzero(&fid, sizeof (fid));
                fid.fid_len = MAXFIDSZ;
                error = vop_fid_pseudo(vp, &fid);
                if (error) {
                        /*
                         * If vop_fid_pseudo returns ENOSPC then the fid
                         * supplied is too small. For now we simply
                         * return EREMOTE.
                         */
                        if (error == ENOSPC)
                                error = EREMOTE;
                        break;
                }

                if (v4srv)
                        exi = checkexport4(&vp->v_vfsp->vfs_fsid, &fid, vp);
                else
                        exi = checkexport(&vp->v_vfsp->vfs_fsid, &fid);

                if (exi != NULL) {
                        /*
                         * Found the export info
                         */
                        break;
                }

                /*
                 * We have just failed finding a matching export.
                 * If we're at the root of this filesystem, then
                 * it's time to stop (with failure).
                 */
                if (vp->v_flag & VROOT) {
                        error = EINVAL;
                        break;
                }

                if (walk != NULL)
                        (*walk)++;

                /*
                 * Now, do a ".." up vp. If dvp is supplied, use it,
                 * otherwise, look it up.
                 */
                if (dvp == NULL) {
                        error = fop_lookup(vp, "..", &dvp, NULL, 0, NULL, cr,
                            NULL, NULL, NULL);
                        if (error)
                                break;
                }
                VN_RELE(vp);
                vp = dvp;
                dvp = NULL;
        }
        VN_RELE(vp);
        if (dvp != NULL) {
                VN_RELE(dvp);
        }
        if (error != 0) {
                if (err != NULL)
                        *err = error;
                return (NULL);
        }
        return (exi);
}

int
chk_clnt_sec(exportinfo_t *exi, struct svc_req *req)
{
        int i, nfsflavor;
        struct secinfo *sp;

        /*
         *  Get the nfs flavor number from xprt.
         */
        nfsflavor = (int)(uintptr_t)req->rq_xprt->xp_cookie;

        sp = exi->exi_export.ex_secinfo;
        for (i = 0; i < exi->exi_export.ex_seccnt; i++) {
                if ((nfsflavor == sp[i].s_secinfo.sc_nfsnum) &&
                    SEC_REF_EXPORTED(sp + i))
                        return (TRUE);
        }
        return (FALSE);
}

/*
 * Make an fhandle from a vnode
 */
int
makefh(fhandle_t *fh, vnode_t *vp, exportinfo_t *exi)
{
        int error;

        *fh = exi->exi_fh;      /* struct copy */

        error = fop_fid(vp, (fid_t *)&fh->fh_len, NULL);
        if (error) {
                /*
                 * Should be something other than EREMOTE
                 */
                return (EREMOTE);
        }
        return (0);
}

/*
 * This routine makes an overloaded V2 fhandle which contains
 * sec modes.
 *
 * Note that the first four octets contain the length octet,
 * the status octet, and two padded octets to make them XDR
 * four-octet aligned.
 *
 *   1   2   3   4                                          32
 * +---+---+---+---+---+---+---+---+   +---+---+---+---+   +---+
 * | l | s |   |   |     sec_1     |...|     sec_n     |...|   |
 * +---+---+---+---+---+---+---+---+   +---+---+---+---+   +---+
 *
 * where
 *
 *   the status octet s indicates whether there are more security
 *   flavors (1 means yes, 0 means no) that require the client to
 *   perform another 0x81 LOOKUP to get them,
 *
 *   the length octet l is the length describing the number of
 *   valid octets that follow.  (l = 4 * n, where n is the number
 *   of security flavors sent in the current overloaded filehandle.)
 *
 *   sec_index should always be in the inclusive range: [1 - ex_seccnt],
 *   and it tells server where to start within the secinfo array.
 *   Usually it will always be 1; however, if more flavors are used
 *   for the public export than can be encoded in the overloaded FH
 *   (7 for NFS2), subsequent SNEGO MCLs will have a larger index
 *   so the server will pick up where it left off from the previous
 *   MCL reply.
 *
 *   With NFS4 support, implicitly allowed flavors are also in
 *   the secinfo array; however, they should not be returned in
 *   SNEGO MCL replies.
 */
int
makefh_ol(fhandle_t *fh, exportinfo_t *exi, uint_t sec_index)
{
        secinfo_t sec[MAX_FLAVORS];
        int totalcnt, i, *ipt, cnt, seccnt, secidx, fh_max_cnt;
        char *c;

        if (fh == NULL || exi == NULL || sec_index < 1)
                return (EREMOTE);

        /*
         * WebNFS clients need to know the unique set of explicitly
         * shared flavors in used for the public export. When
         * "TRUE" is passed to build_seclist_nodups(), only explicitly
         * shared flavors are included in the list.
         */
        seccnt = build_seclist_nodups(&exi->exi_export, sec, TRUE);
        if (sec_index > seccnt)
                return (EREMOTE);

        fh_max_cnt = (NFS_FHSIZE / sizeof (int)) - 1;
        totalcnt = seccnt - sec_index + 1;
        cnt = totalcnt > fh_max_cnt ? fh_max_cnt : totalcnt;

        c = (char *)fh;
        /*
         * Encode the length octet representing the number of
         * security flavors (in bytes) in this overloaded fh.
         */
        *c = cnt * sizeof (int);

        /*
         * Encode the status octet that indicates whether there
         * are more security flavors the client needs to get.
         */
        *(c + 1) = totalcnt > fh_max_cnt;

        /*
         * put security flavors in the overloaded fh
         */
        ipt = (int *)(c + sizeof (int32_t));
        secidx = sec_index - 1;
        for (i = 0; i < cnt; i++) {
                ipt[i] = htonl(sec[i + secidx].s_secinfo.sc_nfsnum);
        }
        return (0);
}

/*
 * Make an nfs_fh3 from a vnode
 */
int
makefh3(nfs_fh3 *fh, vnode_t *vp, struct exportinfo *exi)
{
        int error;
        fid_t fid;

        bzero(&fid, sizeof (fid));
        fid.fid_len = sizeof (fh->fh3_data);
        error = fop_fid(vp, &fid, NULL);
        if (error)
                return (EREMOTE);

        bzero(fh, sizeof (nfs_fh3));
        fh->fh3_fsid = exi->exi_fsid;
        fh->fh3_len = fid.fid_len;
        bcopy(fid.fid_data, fh->fh3_data, fh->fh3_len);

        fh->fh3_xlen = exi->exi_fid.fid_len;
        ASSERT(fh->fh3_xlen <= sizeof (fh->fh3_xdata));
        bcopy(exi->exi_fid.fid_data, fh->fh3_xdata, fh->fh3_xlen);

        fh->fh3_length = sizeof (fh->fh3_fsid)
            + sizeof (fh->fh3_len) + fh->fh3_len
            + sizeof (fh->fh3_xlen) + fh->fh3_xlen;
        fh->fh3_flags = 0;

        return (0);
}

/*
 * This routine makes an overloaded V3 fhandle which contains
 * sec modes.
 *
 *  1        4
 * +--+--+--+--+
 * |    len    |
 * +--+--+--+--+
 *                                               up to 64
 * +--+--+--+--+--+--+--+--+--+--+--+--+     +--+--+--+--+
 * |s |  |  |  |   sec_1   |   sec_2   | ... |   sec_n   |
 * +--+--+--+--+--+--+--+--+--+--+--+--+     +--+--+--+--+
 *
 * len = 4 * (n+1), where n is the number of security flavors
 * sent in the current overloaded filehandle.
 *
 * the status octet s indicates whether there are more security
 * mechanisms (1 means yes, 0 means no) that require the client
 * to perform another 0x81 LOOKUP to get them.
 *
 * Three octets are padded after the status octet.
 */
int
makefh3_ol(nfs_fh3 *fh, struct exportinfo *exi, uint_t sec_index)
{
        secinfo_t sec[MAX_FLAVORS];
        int totalcnt, cnt, *ipt, i, seccnt, fh_max_cnt, secidx;
        char *c;

        if (fh == NULL || exi == NULL || sec_index < 1)
                return (EREMOTE);

        /*
         * WebNFS clients need to know the unique set of explicitly
         * shared flavors in used for the public export. When
         * "TRUE" is passed to build_seclist_nodups(), only explicitly
         * shared flavors are included in the list.
         */
        seccnt = build_seclist_nodups(&exi->exi_export, sec, TRUE);

        if (sec_index > seccnt)
                return (EREMOTE);

        fh_max_cnt = (NFS3_FHSIZE / sizeof (int)) - 1;
        totalcnt = seccnt - sec_index + 1;
        cnt = totalcnt > fh_max_cnt ? fh_max_cnt : totalcnt;

        /*
         * Place the length in fh3_length representing the number
         * of security flavors (in bytes) in this overloaded fh.
         */
        fh->fh3_flags = FH_WEBNFS;
        fh->fh3_length = (cnt+1) * sizeof (int32_t);

        c = (char *)&fh->fh3_u.nfs_fh3_i.fh3_i;
        /*
         * Encode the status octet that indicates whether there
         * are more security flavors the client needs to get.
         */
        *c = totalcnt > fh_max_cnt;

        /*
         * put security flavors in the overloaded fh
         */
        secidx = sec_index - 1;
        ipt = (int *)(c + sizeof (int32_t));
        for (i = 0; i < cnt; i++) {
                ipt[i] = htonl(sec[i + secidx].s_secinfo.sc_nfsnum);
        }
        return (0);
}

/*
 * Make an nfs_fh4 from a vnode
 */
int
makefh4(nfs_fh4 *fh, vnode_t *vp, struct exportinfo *exi)
{
        int error;
        nfs_fh4_fmt_t *fh_fmtp = (nfs_fh4_fmt_t *)fh->nfs_fh4_val;
        fid_t fid;

        bzero(&fid, sizeof (fid));
        fid.fid_len = MAXFIDSZ;
        /*
         * vop_fid_pseudo() is used to set up NFSv4 namespace, so
         * use vop_fid_pseudo() here to get the fid instead of fop_fid.
         */
        error = vop_fid_pseudo(vp, &fid);
        if (error)
                return (error);

        fh->nfs_fh4_len = NFS_FH4_LEN;

        fh_fmtp->fh4_i.fhx_fsid = exi->exi_fh.fh_fsid;
        fh_fmtp->fh4_i.fhx_xlen = exi->exi_fh.fh_xlen;

        bzero(fh_fmtp->fh4_i.fhx_data, sizeof (fh_fmtp->fh4_i.fhx_data));
        bzero(fh_fmtp->fh4_i.fhx_xdata, sizeof (fh_fmtp->fh4_i.fhx_xdata));
        ASSERT(exi->exi_fh.fh_xlen <= sizeof (fh_fmtp->fh4_i.fhx_xdata));
        bcopy(exi->exi_fh.fh_xdata, fh_fmtp->fh4_i.fhx_xdata,
            exi->exi_fh.fh_xlen);

        fh_fmtp->fh4_len = fid.fid_len;
        ASSERT(fid.fid_len <= sizeof (fh_fmtp->fh4_data));
        bcopy(fid.fid_data, fh_fmtp->fh4_data, fid.fid_len);
        fh_fmtp->fh4_flag = 0;

#ifdef VOLATILE_FH_TEST
        /*
         * XXX (temporary?)
         * Use the rnode volatile_id value to add volatility to the fh.
         *
         * For testing purposes there are currently two scenarios, based
         * on whether the filesystem was shared with "volatile_fh"
         * or "expire_on_rename". In the first case, use the value of
         * export struct share_time as the volatile_id. In the second
         * case use the vnode volatile_id value (which is set to the
         * time in which the file was renamed).
         *
         * Note that the above are temporary constructs for testing only
         * XXX
         */
        if (exi->exi_export.ex_flags & EX_VOLRNM) {
                fh_fmtp->fh4_volatile_id = find_volrnm_fh_id(exi, fh);
        } else if (exi->exi_export.ex_flags & EX_VOLFH) {
                fh_fmtp->fh4_volatile_id = exi->exi_volatile_id;
        } else {
                fh_fmtp->fh4_volatile_id = 0;
        }
#endif /* VOLATILE_FH_TEST */

        return (0);
}

/*
 * Convert an fhandle into a vnode.
 * Uses the file id (fh_len + fh_data) in the fhandle to get the vnode.
 * WARNING: users of this routine must do a VN_RELE on the vnode when they
 * are done with it.
 */
vnode_t *
nfs_fhtovp(fhandle_t *fh, struct exportinfo *exi)
{
        vfs_t *vfsp;
        vnode_t *vp;
        int error;
        fid_t *fidp;

        TRACE_0(TR_FAC_NFS, TR_FHTOVP_START,
            "fhtovp_start");

        if (exi == NULL) {
                TRACE_1(TR_FAC_NFS, TR_FHTOVP_END,
                    "fhtovp_end:(%S)", "exi NULL");
                return (NULL);  /* not exported */
        }

        ASSERT(exi->exi_vp != NULL);

        if (PUBLIC_FH2(fh)) {
                if (exi->exi_export.ex_flags & EX_PUBLIC) {
                        TRACE_1(TR_FAC_NFS, TR_FHTOVP_END,
                            "fhtovp_end:(%S)", "root not exported");
                        return (NULL);
                }
                vp = exi->exi_vp;
                VN_HOLD(vp);
                return (vp);
        }

        vfsp = exi->exi_vp->v_vfsp;
        ASSERT(vfsp != NULL);
        fidp = (fid_t *)&fh->fh_len;

        error = VFS_VGET(vfsp, &vp, fidp);
        if (error || vp == NULL) {
                TRACE_1(TR_FAC_NFS, TR_FHTOVP_END,
                    "fhtovp_end:(%S)", "VFS_GET failed or vp NULL");
                return (NULL);
        }
        TRACE_1(TR_FAC_NFS, TR_FHTOVP_END,
            "fhtovp_end:(%S)", "end");
        return (vp);
}

/*
 * Convert an nfs_fh3 into a vnode.
 * Uses the file id (fh_len + fh_data) in the file handle to get the vnode.
 * WARNING: users of this routine must do a VN_RELE on the vnode when they
 * are done with it.
 */
vnode_t *
nfs3_fhtovp(nfs_fh3 *fh, struct exportinfo *exi)
{
        vfs_t *vfsp;
        vnode_t *vp;
        int error;
        fid_t *fidp;

        if (exi == NULL)
                return (NULL);  /* not exported */

        ASSERT(exi->exi_vp != NULL);

        if (PUBLIC_FH3(fh)) {
                if (exi->exi_export.ex_flags & EX_PUBLIC)
                        return (NULL);
                vp = exi->exi_vp;
                VN_HOLD(vp);
                return (vp);
        }

        if (fh->fh3_length < NFS3_OLDFHSIZE ||
            fh->fh3_length > NFS3_MAXFHSIZE)
                return (NULL);

        vfsp = exi->exi_vp->v_vfsp;
        ASSERT(vfsp != NULL);
        fidp = FH3TOFIDP(fh);

        error = VFS_VGET(vfsp, &vp, fidp);
        if (error || vp == NULL)
                return (NULL);

        return (vp);
}

/*
 * Convert an nfs_fh4 into a vnode.
 * Uses the file id (fh_len + fh_data) in the file handle to get the vnode.
 * WARNING: users of this routine must do a VN_RELE on the vnode when they
 * are done with it.
 */
vnode_t *
nfs4_fhtovp(nfs_fh4 *fh, struct exportinfo *exi, nfsstat4 *statp)
{
        vfs_t *vfsp;
        vnode_t *vp = NULL;
        int error;
        fid_t *fidp;
        nfs_fh4_fmt_t *fh_fmtp;
#ifdef VOLATILE_FH_TEST
        uint32_t volatile_id = 0;
#endif /* VOLATILE_FH_TEST */

        if (exi == NULL) {
                *statp = NFS4ERR_STALE;
                return (NULL);  /* not exported */
        }
        ASSERT(exi->exi_vp != NULL);

        /* caller should have checked this */
        ASSERT(fh->nfs_fh4_len >= NFS_FH4_LEN);

        fh_fmtp = (nfs_fh4_fmt_t *)fh->nfs_fh4_val;
        vfsp = exi->exi_vp->v_vfsp;
        ASSERT(vfsp != NULL);
        fidp = (fid_t *)&fh_fmtp->fh4_len;

#ifdef VOLATILE_FH_TEST
        /* XXX check if volatile - should be changed later */
        if (exi->exi_export.ex_flags & (EX_VOLRNM | EX_VOLFH)) {
                /*
                 * Filesystem is shared with volatile filehandles
                 */
                if (exi->exi_export.ex_flags & EX_VOLRNM)
                        volatile_id = find_volrnm_fh_id(exi, fh);
                else
                        volatile_id = exi->exi_volatile_id;

                if (fh_fmtp->fh4_volatile_id != volatile_id) {
                        *statp = NFS4ERR_FHEXPIRED;
                        return (NULL);
                }
        }
        /*
         * XXX even if test_volatile_fh false, the fh may contain a
         * volatile id if obtained when the test was set.
         */
        fh_fmtp->fh4_volatile_id = (uchar_t)0;
#endif /* VOLATILE_FH_TEST */

        error = VFS_VGET(vfsp, &vp, fidp);
        /*
         * If we can not get vp from VFS_VGET, perhaps this is
         * an nfs v2/v3/v4 node in an nfsv4 pseudo filesystem.
         * Check it out.
         */
        if (error && PSEUDO(exi))
                error = nfs4_vget_pseudo(exi, &vp, fidp);

        if (error || vp == NULL) {
                *statp = NFS4ERR_STALE;
                return (NULL);
        }
        /* XXX - disgusting hack */
        if (vp->v_type == VNON && vp->v_flag & V_XATTRDIR)
                vp->v_type = VDIR;
        *statp = NFS4_OK;
        return (vp);
}

/*
 * Find the export structure associated with the given filesystem.
 * If found, then increment the ref count (exi_count).
 */
struct exportinfo *
checkexport(fsid_t *fsid, fid_t *fid)
{
        struct exportinfo *exi;

        rw_enter(&exported_lock, RW_READER);
        for (exi = exptable[exptablehash(fsid, fid)];
            exi != NULL;
            exi = exi->fid_hash.next) {
                if (exportmatch(exi, fsid, fid)) {
                        /*
                         * If this is the place holder for the
                         * public file handle, then return the
                         * real export entry for the public file
                         * handle.
                         */
                        if (exi->exi_export.ex_flags & EX_PUBLIC) {
                                exi = exi_public;
                        }

                        exi_hold(exi);
                        rw_exit(&exported_lock);
                        return (exi);
                }
        }
        rw_exit(&exported_lock);
        return (NULL);
}


/*
 * "old school" version of checkexport() for NFS4.  NFS4
 * rfs4_compound holds exported_lock for duration of compound
 * processing.  This version doesn't manipulate exi_count
 * since NFS4 breaks fundamental assumptions in the exi_count
 * design.
 */
struct exportinfo *
checkexport4(fsid_t *fsid, fid_t *fid, vnode_t *vp)
{
        struct exportinfo *exi;

        ASSERT(RW_LOCK_HELD(&exported_lock));

        for (exi = exptable[exptablehash(fsid, fid)];
            exi != NULL;
            exi = exi->fid_hash.next) {
                if (exportmatch(exi, fsid, fid)) {
                        /*
                         * If this is the place holder for the
                         * public file handle, then return the
                         * real export entry for the public file
                         * handle.
                         */
                        if (exi->exi_export.ex_flags & EX_PUBLIC) {
                                exi = exi_public;
                        }

                        /*
                         * If vp is given, check if vp is the
                         * same vnode as the exported node.
                         *
                         * Since fop_fid of a lofs node returns the
                         * fid of its real node (ufs), the exported
                         * node for lofs and (pseudo) ufs may have
                         * the same fsid and fid.
                         */
                        if (vp == NULL || vp == exi->exi_vp)
                                return (exi);
                }
        }

        return (NULL);
}

/*
 * Free an entire export list node
 */
void
exportfree(struct exportinfo *exi)
{
        struct exportdata *ex;
        struct charset_cache *cache;
        int i;

        ex = &exi->exi_export;

        ASSERT(exi->exi_vp != NULL && !(exi->exi_export.ex_flags & EX_PUBLIC));
        VN_RELE(exi->exi_vp);
        if (exi->exi_dvp != NULL)
                VN_RELE(exi->exi_dvp);

        if (ex->ex_flags & EX_INDEX)
                kmem_free(ex->ex_index, strlen(ex->ex_index) + 1);

        kmem_free(ex->ex_path, ex->ex_pathlen + 1);
        nfsauth_cache_free(exi);

        /*
         * if there is a character set mapping cached, clean it up.
         */
        for (cache = exi->exi_charset; cache != NULL;
            cache = exi->exi_charset) {
                if (cache->inbound != (kiconv_t)-1)
                        (void) kiconv_close(cache->inbound);
                if (cache->outbound != (kiconv_t)-1)
                        (void) kiconv_close(cache->outbound);
                exi->exi_charset = cache->next;
                kmem_free(cache, sizeof (struct charset_cache));
        }

        if (exi->exi_logbuffer != NULL)
                nfslog_disable(exi);

        if (ex->ex_flags & EX_LOG) {
                kmem_free(ex->ex_log_buffer, ex->ex_log_bufferlen + 1);
                kmem_free(ex->ex_tag, ex->ex_taglen + 1);
        }

        if (exi->exi_visible)
                free_visible(exi->exi_visible);

        srv_secinfo_list_free(ex->ex_secinfo, ex->ex_seccnt);

#ifdef VOLATILE_FH_TEST
        free_volrnm_list(exi);
        mutex_destroy(&exi->exi_vol_rename_lock);
#endif /* VOLATILE_FH_TEST */

        mutex_destroy(&exi->exi_lock);
        rw_destroy(&exi->exi_cache_lock);
        /*
         * All nodes in the exi_cache AVL trees were removed and freed in the
         * nfsauth_cache_free() call above.  We will just destroy and free the
         * empty AVL trees here.
         */
        for (i = 0; i < AUTH_TABLESIZE; i++) {
                avl_destroy(exi->exi_cache[i]);
                kmem_free(exi->exi_cache[i], sizeof (avl_tree_t));
        }

        kmem_free(exi, sizeof (*exi));
}

/*
 * load the index file from user space into kernel space.
 */
static int
loadindex(struct exportdata *kex)
{
        int error;
        char index[MAXNAMELEN+1];
        size_t len;

        /*
         * copyinstr copies the complete string including the NULL and
         * returns the len with the NULL byte included in the calculation
         * as long as the max length is not exceeded.
         */
        if (error = copyinstr(kex->ex_index, index, sizeof (index), &len))
                return (error);

        kex->ex_index = kmem_alloc(len, KM_SLEEP);
        bcopy(index, kex->ex_index, len);

        return (0);
}

void
exi_hold(struct exportinfo *exi)
{
        mutex_enter(&exi->exi_lock);
        exi->exi_count++;
        mutex_exit(&exi->exi_lock);
}

/*
 * When a thread completes using exi, it should call exi_rele().
 * exi_rele() decrements exi_count. It releases exi if exi_count == 0, i.e.
 * if this is the last user of exi and exi is not on exportinfo list anymore
 */
void
exi_rele(struct exportinfo *exi)
{
        mutex_enter(&exi->exi_lock);
        exi->exi_count--;
        if (exi->exi_count == 0) {
                mutex_exit(&exi->exi_lock);
                exportfree(exi);
        } else
                mutex_exit(&exi->exi_lock);
}

#ifdef VOLATILE_FH_TEST
/*
 * Test for volatile fh's - add file handle to list and set its volatile id
 * to time it was renamed. If EX_VOLFH is also on and the fs is reshared,
 * the vol_rename queue is purged.
 *
 * XXX This code is for unit testing purposes only... To correctly use it, it
 * needs to tie a rename list to the export struct and (more
 * important), protect access to the exi rename list using a write lock.
 */

/*
 * get the fh vol record if it's in the volatile on rename list. Don't check
 * volatile_id in the file handle - compare only the file handles.
 */
static struct ex_vol_rename *
find_volrnm_fh(struct exportinfo *exi, nfs_fh4 *fh4p)
{
        struct ex_vol_rename *p = NULL;
        fhandle4_t *fhp;

        /* XXX shouldn't we assert &exported_lock held? */
        ASSERT(MUTEX_HELD(&exi->exi_vol_rename_lock));

        if (fh4p->nfs_fh4_len != NFS_FH4_LEN) {
                return (NULL);
        }
        fhp = &((nfs_fh4_fmt_t *)fh4p->nfs_fh4_val)->fh4_i;
        for (p = exi->exi_vol_rename; p != NULL; p = p->vrn_next) {
                if (bcmp(fhp, &p->vrn_fh_fmt.fh4_i,
                    sizeof (fhandle4_t)) == 0)
                        break;
        }
        return (p);
}

/*
 * get the volatile id for the fh (if there is - else return 0). Ignore the
 * volatile_id in the file handle - compare only the file handles.
 */
static uint32_t
find_volrnm_fh_id(struct exportinfo *exi, nfs_fh4 *fh4p)
{
        struct ex_vol_rename *p;
        uint32_t volatile_id;

        mutex_enter(&exi->exi_vol_rename_lock);
        p = find_volrnm_fh(exi, fh4p);
        volatile_id = (p ? p->vrn_fh_fmt.fh4_volatile_id :
            exi->exi_volatile_id);
        mutex_exit(&exi->exi_vol_rename_lock);
        return (volatile_id);
}

/*
 * Free the volatile on rename list - will be called if a filesystem is
 * unshared or reshared without EX_VOLRNM
 */
static void
free_volrnm_list(struct exportinfo *exi)
{
        struct ex_vol_rename *p, *pnext;

        /* no need to hold mutex lock - this one is called from exportfree */
        for (p = exi->exi_vol_rename; p != NULL; p = pnext) {
                pnext = p->vrn_next;
                kmem_free(p, sizeof (*p));
        }
        exi->exi_vol_rename = NULL;
}

/*
 * Add a file handle to the volatile on rename list.
 */
void
add_volrnm_fh(struct exportinfo *exi, vnode_t *vp)
{
        struct ex_vol_rename *p;
        char fhbuf[NFS4_FHSIZE];
        nfs_fh4 fh4;
        int error;

        fh4.nfs_fh4_val = fhbuf;
        error = makefh4(&fh4, vp, exi);
        if ((error) || (fh4.nfs_fh4_len != sizeof (p->vrn_fh_fmt))) {
                return;
        }

        mutex_enter(&exi->exi_vol_rename_lock);

        p = find_volrnm_fh(exi, &fh4);

        if (p == NULL) {
                p = kmem_alloc(sizeof (*p), KM_SLEEP);
                bcopy(fh4.nfs_fh4_val, &p->vrn_fh_fmt, sizeof (p->vrn_fh_fmt));
                p->vrn_next = exi->exi_vol_rename;
                exi->exi_vol_rename = p;
        }

        p->vrn_fh_fmt.fh4_volatile_id = gethrestime_sec();
        mutex_exit(&exi->exi_vol_rename_lock);
}

#endif /* VOLATILE_FH_TEST */