/*
 *
 * 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 (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2020 Joyent, Inc.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <alloca.h>
#include <assert.h>
#include <limits.h>
#include <zone.h>
#include <fm/topo_mod.h>
#include <fm/topo_hc.h>
#include <fm/fmd_fmri.h>
#include <sys/param.h>
#include <sys/systeminfo.h>
#include <sys/fm/protocol.h>
#include <sys/stat.h>
#include <sys/systeminfo.h>
#include <sys/utsname.h>

#include <topo_method.h>
#include <topo_module.h>
#include <topo_subr.h>
#include <topo_prop.h>
#include <topo_tree.h>
#include <hc.h>

static int hc_enum(topo_mod_t *, tnode_t *, const char *, topo_instance_t,
    topo_instance_t, void *, void *);
static void hc_release(topo_mod_t *, tnode_t *);
static int hc_fmri_nvl2str(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_str2nvl(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_compare(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_present(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_replaced(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_unusable(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_expand(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_retire(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_unretire(topo_mod_t *, tnode_t *, topo_version_t, nvlist_t *,
    nvlist_t **);
static int hc_fmri_service_state(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_create_meth(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_prop_get(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_prop_set(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_pgrp_get(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);
static int hc_fmri_facility(topo_mod_t *, tnode_t *, topo_version_t,
    nvlist_t *, nvlist_t **);

static nvlist_t *hc_fmri_create(topo_mod_t *, nvlist_t *, int, const char *,
    topo_instance_t inst, const nvlist_t *, const char *, const char *,
    const char *);

const topo_method_t hc_methods[] = {
        { TOPO_METH_NVL2STR, TOPO_METH_NVL2STR_DESC, TOPO_METH_NVL2STR_VERSION,
            TOPO_STABILITY_INTERNAL, hc_fmri_nvl2str },
        { TOPO_METH_STR2NVL, TOPO_METH_STR2NVL_DESC, TOPO_METH_STR2NVL_VERSION,
            TOPO_STABILITY_INTERNAL, hc_fmri_str2nvl },
        { TOPO_METH_COMPARE, TOPO_METH_COMPARE_DESC, TOPO_METH_COMPARE_VERSION,
            TOPO_STABILITY_INTERNAL, hc_compare },
        { TOPO_METH_PRESENT, TOPO_METH_PRESENT_DESC, TOPO_METH_PRESENT_VERSION,
            TOPO_STABILITY_INTERNAL, hc_fmri_present },
        { TOPO_METH_REPLACED, TOPO_METH_REPLACED_DESC,
            TOPO_METH_REPLACED_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_replaced },
        { TOPO_METH_UNUSABLE, TOPO_METH_UNUSABLE_DESC,
            TOPO_METH_UNUSABLE_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_unusable },
        { TOPO_METH_EXPAND, TOPO_METH_EXPAND_DESC,
            TOPO_METH_EXPAND_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_expand },
        { TOPO_METH_RETIRE, TOPO_METH_RETIRE_DESC,
            TOPO_METH_RETIRE_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_retire },
        { TOPO_METH_UNRETIRE, TOPO_METH_UNRETIRE_DESC,
            TOPO_METH_UNRETIRE_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_unretire },
        { TOPO_METH_SERVICE_STATE, TOPO_METH_SERVICE_STATE_DESC,
            TOPO_METH_SERVICE_STATE_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_service_state },
        { TOPO_METH_FMRI, TOPO_METH_FMRI_DESC, TOPO_METH_FMRI_VERSION,
            TOPO_STABILITY_INTERNAL, hc_fmri_create_meth },
        { TOPO_METH_PROP_GET, TOPO_METH_PROP_GET_DESC,
            TOPO_METH_PROP_GET_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_prop_get },
        { TOPO_METH_PROP_SET, TOPO_METH_PROP_SET_DESC,
            TOPO_METH_PROP_SET_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_prop_set },
        { TOPO_METH_PGRP_GET, TOPO_METH_PGRP_GET_DESC,
            TOPO_METH_PGRP_GET_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_pgrp_get },
        { TOPO_METH_FACILITY, TOPO_METH_FACILITY_DESC,
            TOPO_METH_FACILITY_VERSION, TOPO_STABILITY_INTERNAL,
            hc_fmri_facility },
        { NULL }
};

static const topo_method_t fru_container_methods[] = {
        { TOPO_METH_OCCUPIED, TOPO_METH_OCCUPIED_DESC,
            TOPO_METH_OCCUPIED_VERSION, TOPO_STABILITY_INTERNAL,
            topo_mod_hc_occupied },
        { NULL }
};

static const topo_modops_t hc_ops =
        { hc_enum, hc_release };
static const topo_modinfo_t hc_info =
        { HC, FM_FMRI_SCHEME_HC, HC_VERSION, &hc_ops };

static const hcc_t hc_canon[] = {
        { BANK, TOPO_STABILITY_PRIVATE },
        { BAY, TOPO_STABILITY_PRIVATE },
        { BLADE, TOPO_STABILITY_PRIVATE },
        { BRANCH, TOPO_STABILITY_PRIVATE },
        { CACHE, TOPO_STABILITY_PRIVATE },
        { CCD, TOPO_STABILITY_PRIVATE },
        { CCX, TOPO_STABILITY_PRIVATE },
        { CMP, TOPO_STABILITY_PRIVATE },
        { CENTERPLANE, TOPO_STABILITY_PRIVATE },
        { CHASSIS, TOPO_STABILITY_PRIVATE },
        { CHIP, TOPO_STABILITY_PRIVATE },
        { CHIPSET, TOPO_STABILITY_PRIVATE },
        { CHIP_SELECT, TOPO_STABILITY_PRIVATE },
        { CORE, TOPO_STABILITY_PRIVATE },
        { CONTROLLER, TOPO_STABILITY_PRIVATE },
        { CPU, TOPO_STABILITY_PRIVATE },
        { CPUBOARD, TOPO_STABILITY_PRIVATE },
        { DIMM, TOPO_STABILITY_PRIVATE },
        { DISK, TOPO_STABILITY_PRIVATE },
        { DRAM, TOPO_STABILITY_PRIVATE },
        { DRAMCHANNEL, TOPO_STABILITY_PRIVATE },
        { FAN, TOPO_STABILITY_PRIVATE },
        { FANBOARD, TOPO_STABILITY_PRIVATE },
        { FANMODULE, TOPO_STABILITY_PRIVATE },
        { HBA, TOPO_STABILITY_PRIVATE },
        { HOSTBRIDGE, TOPO_STABILITY_PRIVATE },
        { INTERCONNECT, TOPO_STABILITY_PRIVATE },
        { IOBOARD, TOPO_STABILITY_PRIVATE },
        { IPORT, TOPO_STABILITY_PRIVATE },
        { MEMBOARD, TOPO_STABILITY_PRIVATE },
        { MEMORYBUFFER, TOPO_STABILITY_PRIVATE },
        { MEMORYCONTROL, TOPO_STABILITY_PRIVATE },
        { MICROCORE, TOPO_STABILITY_PRIVATE },
        { MOTHERBOARD, TOPO_STABILITY_PRIVATE },
        { NIU, TOPO_STABILITY_PRIVATE },
        { NIUFN, TOPO_STABILITY_PRIVATE },
        { NVME, TOPO_STABILITY_PRIVATE },
        { PCI_BUS, TOPO_STABILITY_PRIVATE },
        { PCI_DEVICE, TOPO_STABILITY_PRIVATE },
        { PCI_FUNCTION, TOPO_STABILITY_PRIVATE },
        { PCIEX_BUS, TOPO_STABILITY_PRIVATE },
        { PCIEX_DEVICE, TOPO_STABILITY_PRIVATE },
        { PCIEX_FUNCTION, TOPO_STABILITY_PRIVATE },
        { PCIEX_ROOT, TOPO_STABILITY_PRIVATE },
        { PCIEX_SWUP, TOPO_STABILITY_PRIVATE },
        { PCIEX_SWDWN, TOPO_STABILITY_PRIVATE },
        { PORT, TOPO_STABILITY_PRIVATE },
        { POWERBOARD, TOPO_STABILITY_PRIVATE },
        { POWERMODULE, TOPO_STABILITY_PRIVATE },
        { PSU, TOPO_STABILITY_PRIVATE },
        { RANK, TOPO_STABILITY_PRIVATE },
        { RECEPTACLE, TOPO_STABILITY_PRIVATE },
        { RISER, TOPO_STABILITY_PRIVATE },
        { SASEXPANDER, TOPO_STABILITY_PRIVATE },
        { SCSI_DEVICE, TOPO_STABILITY_PRIVATE },
        { SHELF, TOPO_STABILITY_PRIVATE },
        { SES_ENCLOSURE, TOPO_STABILITY_PRIVATE },
        { SLOT, TOPO_STABILITY_PRIVATE },
        { SMP_DEVICE, TOPO_STABILITY_PRIVATE },
        { SP, TOPO_STABILITY_PRIVATE },
        { STRAND, TOPO_STABILITY_PRIVATE },
        { SUBCHASSIS, TOPO_STABILITY_PRIVATE },
        { SYSTEMBOARD, TOPO_STABILITY_PRIVATE },
        { TRANSCEIVER, TOPO_STABILITY_PRIVATE },
        { UFM, TOPO_STABILITY_PRIVATE },
        { USB_DEVICE, TOPO_STABILITY_PRIVATE },
        { XAUI, TOPO_STABILITY_PRIVATE },
        { XFP, TOPO_STABILITY_PRIVATE }
};

static int hc_ncanon = sizeof (hc_canon) / sizeof (hcc_t);

int
hc_init(topo_mod_t *mod, topo_version_t version)
{
        /*
         * Turn on module debugging output
         */
        if (getenv("TOPOHCDEBUG"))
                topo_mod_setdebug(mod);

        topo_mod_dprintf(mod, "initializing hc builtin\n");

        if (version != HC_VERSION)
                return (topo_mod_seterrno(mod, EMOD_VER_NEW));

        if (topo_mod_register(mod, &hc_info, TOPO_VERSION) != 0) {
                topo_mod_dprintf(mod, "failed to register hc: "
                    "%s\n", topo_mod_errmsg(mod));
                return (-1); /* mod errno already set */
        }

        return (0);
}

void
hc_fini(topo_mod_t *mod)
{
        topo_mod_unregister(mod);
}

/*ARGSUSED*/
int
hc_enum(topo_mod_t *mod, tnode_t *pnode, const char *name, topo_instance_t min,
    topo_instance_t max, void *notused1, void *notused2)
{
        int isglobal = (getzoneid() == GLOBAL_ZONEID);
        nvlist_t *pfmri = NULL;
        nvlist_t *nvl;
        nvlist_t *auth;
        tnode_t *node;
        int err;
        /*
         * Register root node methods
         */
        if (strcmp(name, HC) == 0) {
                (void) topo_method_register(mod, pnode, hc_methods);
                return (0);
        }
        if (min != max) {
                topo_mod_dprintf(mod,
                    "Request to enumerate %s component with an "
                    "ambiguous instance number, min (%" PRIu64 ") != max (%"
                    PRIu64 ").\n", HC, min, max);
                return (topo_mod_seterrno(mod, EINVAL));
        }

        if (!isglobal)
                return (0);

        (void) topo_node_resource(pnode, &pfmri, &err);
        auth = topo_mod_auth(mod, pnode);
        nvl = hc_fmri_create(mod, pfmri, FM_HC_SCHEME_VERSION, name, min,
            auth, NULL, NULL, NULL);
        nvlist_free(pfmri);     /* callee ignores NULLs */
        if (nvl == NULL) {
                nvlist_free(auth);
                return (-1);
        }

        if ((node = topo_node_bind(mod, pnode, name, min, nvl)) == NULL) {
                topo_mod_dprintf(mod, "topo_node_bind failed: %s\n",
                    topo_strerror(topo_mod_errno(mod)));
                nvlist_free(auth);
                nvlist_free(nvl);
                return (-1);
        }
        if (strcmp(name, BAY) == 0 || strcmp(name, PORT) == 0 ||
            strcmp(name, RECEPTACLE) == 0 || strcmp(name, SLOT) == 0) {
                if (topo_method_register(mod, node, fru_container_methods) <
                    0) {
                        topo_mod_dprintf(mod, "failed to register methods on "
                            "%s=%" PRIu64 "\n", name, min);
                        return (-1);
                }
        }

        /*
         * Set FRU for the motherboard node
         */
        if (strcmp(name, MOTHERBOARD) == 0)
                (void) topo_node_fru_set(node, nvl, 0, &err);

        topo_pgroup_hcset(node, auth);
        nvlist_free(nvl);
        nvlist_free(auth);

        return (0);
}

/*ARGSUSED*/
static void
hc_release(topo_mod_t *mp, tnode_t *node)
{
        topo_method_unregister_all(mp, node);
}

static int
fmri_compare(topo_mod_t *mod, nvlist_t *nv1, nvlist_t *nv2)
{
        uint8_t v1, v2;
        nvlist_t **hcp1, **hcp2;
        nvlist_t *f1 = NULL, *f2 = NULL;
        int err, i;
        uint_t nhcp1, nhcp2;
        char *f1str, *f2str;

        if (nvlist_lookup_uint8(nv1, FM_VERSION, &v1) != 0 ||
            nvlist_lookup_uint8(nv2, FM_VERSION, &v2) != 0 ||
            v1 > FM_HC_SCHEME_VERSION || v2 > FM_HC_SCHEME_VERSION)
                return (topo_mod_seterrno(mod, EMOD_FMRI_VERSION));

        err = nvlist_lookup_nvlist_array(nv1, FM_FMRI_HC_LIST, &hcp1, &nhcp1);
        err |= nvlist_lookup_nvlist_array(nv2, FM_FMRI_HC_LIST, &hcp2, &nhcp2);
        if (err != 0)
                return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));

        if (nhcp1 != nhcp2)
                return (0);

        for (i = 0; i < nhcp1; i++) {
                char *nm1 = NULL;
                char *nm2 = NULL;
                char *id1 = NULL;
                char *id2 = NULL;

                (void) nvlist_lookup_string(hcp1[i], FM_FMRI_HC_NAME, &nm1);
                (void) nvlist_lookup_string(hcp2[i], FM_FMRI_HC_NAME, &nm2);
                (void) nvlist_lookup_string(hcp1[i], FM_FMRI_HC_ID, &id1);
                (void) nvlist_lookup_string(hcp2[i], FM_FMRI_HC_ID, &id2);
                if (nm1 == NULL || nm2 == NULL || id1 == NULL || id2 == NULL)
                        return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));

                if (strcmp(nm1, nm2) == 0 && strcmp(id1, id2) == 0)
                        continue;

                return (0);
        }

        /*
         * Finally, check if the FMRI's represent a facility node.  If so, then
         * verify that the facilty type ("sensor"|"indicator") and facility
         * name match.
         */
        (void) nvlist_lookup_nvlist(nv1, FM_FMRI_FACILITY, &f1);
        (void) nvlist_lookup_nvlist(nv2, FM_FMRI_FACILITY, &f2);

        if (f1 == NULL && f2 == NULL)
                return (1);
        else if (f1 == NULL || f2 == NULL)
                return (0);

        if (nvlist_lookup_string(f1, FM_FMRI_FACILITY_NAME, &f1str) == 0 &&
            nvlist_lookup_string(f2, FM_FMRI_FACILITY_NAME, &f2str) == 0 &&
            strcmp(f1str, f2str) == 0 &&
            nvlist_lookup_string(f1, FM_FMRI_FACILITY_TYPE, &f1str) == 0 &&
            nvlist_lookup_string(f2, FM_FMRI_FACILITY_TYPE, &f2str) == 0 &&
            strcmp(f1str, f2str) == 0) {
                return (1);
        }
        return (0);
}

/*ARGSUSED*/
static int
hc_compare(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int ret;
        uint32_t compare;
        nvlist_t *nv1, *nv2;

        if (version > TOPO_METH_COMPARE_VERSION)
                return (topo_mod_seterrno(mod, EMOD_VER_NEW));

        if (nvlist_lookup_nvlist(in, TOPO_METH_FMRI_ARG_NV1, &nv1) != 0 ||
            nvlist_lookup_nvlist(in, TOPO_METH_FMRI_ARG_NV2, &nv2) != 0)
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));

        ret = fmri_compare(mod, nv1, nv2);
        if (ret < 0)
                return (-1);

        compare = ret;
        if (topo_mod_nvalloc(mod, out, NV_UNIQUE_NAME) == 0) {
                if (nvlist_add_uint32(*out, TOPO_METH_COMPARE_RET,
                    compare) == 0)
                        return (0);
                else
                        nvlist_free(*out);
        }

        return (-1);
}

static ssize_t
fmri_nvl2str(nvlist_t *nvl, char *buf, size_t buflen)
{
        nvlist_t **hcprs = NULL;
        nvlist_t *hcsp = NULL;
        nvlist_t *anvl = NULL;
        nvpair_t *apair;
        nvlist_t *fnvl;
        uint8_t version;
        ssize_t size = 0;
        uint_t hcnprs;
        char *serial = NULL;
        char *part = NULL;
        char *root = NULL;
        char *rev = NULL;
        char *aname, *aval;
        char *fname = NULL, *ftype = NULL;
        int err, i;

        if (nvlist_lookup_uint8(nvl, FM_VERSION, &version) != 0 ||
            version > FM_HC_SCHEME_VERSION)
                return (0);

        /* Get authority, if present */
        err = nvlist_lookup_nvlist(nvl, FM_FMRI_AUTHORITY, &anvl);
        if (err != 0 && err != ENOENT)
                return (0);

        (void) nvlist_lookup_string(nvl, FM_FMRI_HC_ROOT, &root);

        err = nvlist_lookup_nvlist_array(nvl, FM_FMRI_HC_LIST, &hcprs, &hcnprs);
        if (err != 0 || hcprs == NULL)
                return (0);

        (void) nvlist_lookup_string(nvl, FM_FMRI_HC_SERIAL_ID, &serial);
        (void) nvlist_lookup_string(nvl, FM_FMRI_HC_PART, &part);
        (void) nvlist_lookup_string(nvl, FM_FMRI_HC_REVISION, &rev);

        /* hc:// */
        topo_fmristr_build(&size, buf, buflen, FM_FMRI_SCHEME_HC, NULL, "://");

        /* authority, if any */
        if (anvl != NULL) {
                for (apair = nvlist_next_nvpair(anvl, NULL);
                    apair != NULL; apair = nvlist_next_nvpair(anvl, apair)) {
                        if (nvpair_type(apair) != DATA_TYPE_STRING ||
                            nvpair_value_string(apair, &aval) != 0)
                                continue;
                        aname = nvpair_name(apair);
                        topo_fmristr_build(&size, buf, buflen, ":", NULL, NULL);
                        topo_fmristr_build(&size, buf, buflen, "=",
                            aname, aval);
                }
        }

        /* hardware-id part */
        topo_fmristr_build(&size,
            buf, buflen, serial, ":" FM_FMRI_HC_SERIAL_ID "=", NULL);
        topo_fmristr_build(&size,
            buf, buflen, part, ":" FM_FMRI_HC_PART "=", NULL);
        topo_fmristr_build(&size,
            buf, buflen, rev, ":" FM_FMRI_HC_REVISION "=", NULL);

        /* separating slash */
        topo_fmristr_build(&size, buf, buflen, "/", NULL, NULL);

        /* hc-root */
        if (root)
                topo_fmristr_build(&size, buf, buflen, root, NULL, NULL);

        /* all the pairs */
        for (i = 0; i < hcnprs; i++) {
                char *nm = NULL;
                char *id = NULL;

                if (i > 0)
                        topo_fmristr_build(&size,
                            buf, buflen, "/", NULL, NULL);
                (void) nvlist_lookup_string(hcprs[i], FM_FMRI_HC_NAME, &nm);
                (void) nvlist_lookup_string(hcprs[i], FM_FMRI_HC_ID, &id);
                if (nm == NULL || id == NULL)
                        return (0);
                topo_fmristr_build(&size, buf, buflen, nm, NULL, "=");
                topo_fmristr_build(&size, buf, buflen, id, NULL, NULL);
        }

        /* append offset/physaddr if it exists in hc-specific */
        if (nvlist_lookup_nvlist(nvl, FM_FMRI_HC_SPECIFIC, &hcsp) == 0) {
                char *hcsn = NULL;
                char hexstr[17];
                uint64_t val;

                if (nvlist_lookup_uint64(hcsp, FM_FMRI_HC_SPECIFIC_OFFSET,
                    &val) == 0 || nvlist_lookup_uint64(hcsp,
                    "asru-" FM_FMRI_HC_SPECIFIC_OFFSET, &val) == 0)
                        hcsn = FM_FMRI_HC_SPECIFIC_OFFSET;
                else if (nvlist_lookup_uint64(hcsp,
                    FM_FMRI_HC_SPECIFIC_PHYSADDR, &val) == 0 ||
                    nvlist_lookup_uint64(hcsp,
                    "asru-" FM_FMRI_HC_SPECIFIC_PHYSADDR, &val) == 0)
                        hcsn = FM_FMRI_HC_SPECIFIC_PHYSADDR;

                if (hcsn != NULL) {
                        (void) snprintf(hexstr, sizeof (hexstr), "%llx", val);
                        topo_fmristr_build(&size, buf, buflen, "/", NULL, NULL);
                        topo_fmristr_build(&size, buf, buflen, "=", hcsn,
                            hexstr);
                }
        }

        /*
         * If the nvlist represents a facility node, then we append the
         * facility type and name to the end of the string representation using
         * the format below:
         *
         * ?<ftype>=<fname>
         */
        if (nvlist_lookup_nvlist(nvl, FM_FMRI_FACILITY, &fnvl) == 0) {
                if (nvlist_lookup_string(fnvl, FM_FMRI_FACILITY_NAME,
                    &fname) != 0 || nvlist_lookup_string(fnvl,
                    FM_FMRI_FACILITY_TYPE, &ftype) != 0)
                        return (0);
                topo_fmristr_build(&size, buf, buflen, "?", NULL, NULL);
                topo_fmristr_build(&size, buf, buflen, "=", ftype, fname);
        }

        return (size);
}

/*ARGSUSED*/
static int
hc_fmri_nvl2str(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *nvl, nvlist_t **out)
{
        ssize_t len;
        char *name = NULL;
        nvlist_t *fmristr;

        if (version > TOPO_METH_NVL2STR_VERSION)
                return (topo_mod_seterrno(mod, EMOD_VER_NEW));

        if ((len = fmri_nvl2str(nvl, NULL, 0)) == 0 ||
            (name = topo_mod_alloc(mod, len + 1)) == NULL ||
            fmri_nvl2str(nvl, name, len + 1) == 0) {
                if (name != NULL)
                        topo_mod_free(mod, name, len + 1);
                return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
        }

        if (topo_mod_nvalloc(mod, &fmristr, NV_UNIQUE_NAME) != 0) {
                topo_mod_free(mod, name, len + 1);
                return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
        }
        if (nvlist_add_string(fmristr, "fmri-string", name) != 0) {
                topo_mod_free(mod, name, len + 1);
                nvlist_free(fmristr);
                return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
        }
        topo_mod_free(mod, name, len + 1);
        *out = fmristr;

        return (0);
}

static nvlist_t *
hc_base_fmri_create(topo_mod_t *mod, const nvlist_t *auth, const char *part,
    const char *rev, const char *serial)
{
        nvlist_t *fmri;
        int err = 0;

        /*
         * Create base HC nvlist
         */
        if (topo_mod_nvalloc(mod, &fmri, NV_UNIQUE_NAME) != 0)
                return (NULL);

        err = nvlist_add_uint8(fmri, FM_VERSION, FM_HC_SCHEME_VERSION);
        err |= nvlist_add_string(fmri, FM_FMRI_SCHEME, FM_FMRI_SCHEME_HC);
        err |= nvlist_add_string(fmri, FM_FMRI_HC_ROOT, "");
        if (err != 0) {
                nvlist_free(fmri);
                return (NULL);
        }

        /*
         * Add optional payload members
         */
        if (serial != NULL)
                (void) nvlist_add_string(fmri, FM_FMRI_HC_SERIAL_ID, serial);
        if (part != NULL)
                (void) nvlist_add_string(fmri, FM_FMRI_HC_PART, part);
        if (rev != NULL)
                (void) nvlist_add_string(fmri, FM_FMRI_HC_REVISION, rev);
        if (auth != NULL)
                (void) nvlist_add_nvlist(fmri, FM_FMRI_AUTHORITY,
                    (nvlist_t *)auth);

        return (fmri);
}

static nvlist_t **
make_hc_pairs(topo_mod_t *mod, char *fmri, int *num)
{
        nvlist_t **pa;
        char *hc, *fromstr;
        char *starti, *startn, *endi, *endi2;
        char *ne, *ns;
        char *cname = NULL;
        char *find;
        char *cid = NULL;
        int nslashes = 0;
        int npairs = 0;
        int i, hclen;

        if ((hc = topo_mod_strdup(mod, fmri + 5)) == NULL)
                return (NULL);

        hclen = strlen(hc) + 1;

        /*
         * Count equal signs and slashes to determine how many
         * hc-pairs will be present in the final FMRI.  There should
         * be at least as many slashes as equal signs.  There can be
         * more, though if the string after an = includes them.
         */
        if ((fromstr = strchr(hc, '/')) == NULL)
                return (NULL);

        find = fromstr;
        while ((ne = strchr(find, '=')) != NULL) {
                find = ne + 1;
                npairs++;
        }

        find = fromstr;
        while ((ns = strchr(find, '/')) != NULL) {
                find = ns + 1;
                nslashes++;
        }

        /*
         * Do we appear to have a well-formed string version of the FMRI?
         */
        if (nslashes < npairs || npairs == 0) {
                topo_mod_free(mod, hc, hclen);
                return (NULL);
        }

        *num = npairs;

        find = fromstr;

        if ((pa = topo_mod_zalloc(mod, npairs * sizeof (nvlist_t *))) == NULL) {
                topo_mod_free(mod, hc, hclen);
                return (NULL);
        }

        /*
         * We go through a pretty complicated procedure to find the
         * name and id for each pair.  That's because, unfortunately,
         * we have some ids that can have slashes within them.  So
         * we can't just search for the next slash after the equal sign
         * and decide that starts a new pair.  Instead we have to find
         * an equal sign for the next pair and work our way back to the
         * slash from there.
         */
        for (i = 0; i < npairs; i++) {
                startn = strchr(find, '/');
                if (startn == NULL)
                        break;
                startn++;
                starti = strchr(find, '=');
                if (starti == NULL)
                        break;
                *starti = '\0';
                if ((cname = topo_mod_strdup(mod, startn)) == NULL)
                        break;
                *starti++ = '=';
                endi = strchr(starti, '=');
                if (endi != NULL) {
                        *endi = '\0';
                        endi2 = strrchr(starti, '/');
                        if (endi2 == NULL)
                                break;
                        *endi = '=';
                        *endi2 = '\0';
                        if ((cid = topo_mod_strdup(mod, starti)) == NULL)
                                break;
                        *endi2 = '/';
                        find = endi2;
                } else {
                        if ((cid = topo_mod_strdup(mod, starti)) == NULL)
                                break;
                        find = starti + strlen(starti);
                }
                if (topo_mod_nvalloc(mod, &pa[i], NV_UNIQUE_NAME) < 0)
                        break;

                if (nvlist_add_string(pa[i], FM_FMRI_HC_NAME, cname) ||
                    nvlist_add_string(pa[i], FM_FMRI_HC_ID, cid))
                        break;

                topo_mod_strfree(mod, cname);
                topo_mod_strfree(mod, cid);
                cname = NULL;
                cid = NULL;
        }

        topo_mod_strfree(mod, cname);
        topo_mod_strfree(mod, cid);

        if (i < npairs) {
                for (i = 0; i < npairs; i++)
                        nvlist_free(pa[i]);
                topo_mod_free(mod, pa, npairs * sizeof (nvlist_t *));
                topo_mod_free(mod, hc, hclen);
                return (NULL);
        }

        topo_mod_free(mod, hc, hclen);

        return (pa);
}

int
make_hc_auth(topo_mod_t *mod, char *fmri, char **serial, char **part,
    char **rev, nvlist_t **auth)
{
        char *starti, *startn, *endi, *copy;
        char *aname = NULL, *aid = NULL, *fs;
        nvlist_t *na = NULL;
        size_t len;

        if ((copy = topo_mod_strdup(mod, fmri + 5)) == NULL)
                return (-1);

        len = strlen(copy);

        /*
         * Make sure there are a valid authority members
         */
        startn = strchr(copy, ':');
        fs = strchr(copy, '/');

        if (startn == NULL || fs == NULL) {
                topo_mod_strfree(mod, copy);
                return (0);
        }

        /*
         * The first colon we encounter must occur before the
         * first slash
         */
        if (startn > fs)
                goto hcabail;

        do {
                if (++startn >= copy + len)
                        break;

                if ((starti = strchr(startn, '=')) == NULL)
                        goto hcabail;

                *starti = '\0';
                if (++starti > copy + len)
                        goto hcabail;

                if ((aname = topo_mod_strdup(mod, startn)) == NULL)
                        goto hcabail;

                startn = endi = strchr(starti, ':');
                if (endi == NULL)
                        if ((endi = strchr(starti, '/')) == NULL)
                                break;

                *endi = '\0';
                if ((aid = topo_mod_strdup(mod, starti)) == NULL)
                        goto hcabail;

                /*
                 * Return possible serial, part and revision
                 */
                if (strcmp(aname, FM_FMRI_HC_SERIAL_ID) == 0) {
                        *serial = topo_mod_strdup(mod, aid);
                } else if (strcmp(aname, FM_FMRI_HC_PART) == 0) {
                        *part = topo_mod_strdup(mod, aid);
                } else if (strcmp(aname, FM_FMRI_HC_REVISION) == 0) {
                        *rev = topo_mod_strdup(mod, aid);
                } else {
                        if (na == NULL) {
                                if (topo_mod_nvalloc(mod, &na,
                                    NV_UNIQUE_NAME) == 0) {
                                        (void) nvlist_add_string(na, aname,
                                            aid);
                                }
                        } else {
                                (void) nvlist_add_string(na, aname, aid);
                        }
                }
                topo_mod_strfree(mod, aname);
                topo_mod_strfree(mod, aid);
                aname = aid = NULL;

        } while (startn != NULL);

        *auth = na;

        topo_mod_free(mod, copy, len + 1);
        return (0);

hcabail:
        topo_mod_free(mod, copy, len + 1);
        topo_mod_strfree(mod, aname);
        topo_mod_strfree(mod, aid);
        nvlist_free(na);
        return (-1);
}


/*
 * This function creates an nvlist to represent the facility portion of an
 * hc-scheme node, given a string representation of the fmri.  This is called by
 * hc_fmri_str2nvl.  If the string does not contain a facility component
 * (e.g. ?<ftype>=<fname>) then it bails early and returns 0.
 *
 * On failure it returns -1 and sets the topo mod errno
 */
int
make_facility(topo_mod_t *mod, char *str, nvlist_t **nvl)
{
        char *fac, *copy, *fname, *ftype;
        nvlist_t *nf = NULL;
        size_t len;

        if ((fac = strchr(str, '?')) == NULL)
                return (0);

        ++fac;
        if ((copy = topo_mod_strdup(mod, fac)) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        fac = copy;
        len = strlen(fac);

        if ((fname = strchr(fac, '=')) == NULL) {
                topo_mod_free(mod, copy, len + 1);
                return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));
        }

        fname[0] = '\0';
        ++fname;
        ftype = fac;

        if (topo_mod_nvalloc(mod, &nf, NV_UNIQUE_NAME) != 0) {
                topo_mod_free(mod, copy, len + 1);
                return (topo_mod_seterrno(mod, EMOD_NOMEM));
        }

        if (nvlist_add_string(nf, FM_FMRI_FACILITY_NAME, fname) != 0 ||
            nvlist_add_string(nf, FM_FMRI_FACILITY_TYPE, ftype) != 0) {
                topo_mod_free(mod, copy, len + 1);
                return (topo_mod_seterrno(mod, EMOD_FMRI_NVL));
        }

        topo_mod_free(mod, copy, len + 1);

        *nvl = nf;

        return (0);
}

/*ARGSUSED*/
static int
hc_fmri_str2nvl(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        nvlist_t **pa = NULL;
        nvlist_t *nf = NULL;
        nvlist_t *auth = NULL;
        nvlist_t *fac = NULL;
        char *str;
        char *serial = NULL, *part = NULL, *rev = NULL, *hcsn = NULL;
        int npairs, n;
        int i, e;

        if (version > TOPO_METH_STR2NVL_VERSION)
                return (topo_mod_seterrno(mod, EMOD_VER_NEW));

        if (nvlist_lookup_string(in, "fmri-string", &str) != 0)
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));

        /* We're expecting a string version of an hc scheme FMRI */
        if (strncmp(str, "hc://", 5) != 0)
                return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));

        if ((pa = make_hc_pairs(mod, str, &npairs)) == NULL)
                return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));

        if (make_hc_auth(mod, str, &serial, &part, &rev, &auth) < 0)
                goto hcfmbail;

        if ((nf = hc_base_fmri_create(mod, auth, part, rev, serial)) == NULL)
                goto hcfmbail;

        n = npairs;

        /*
         * If the last pair in hc-list is offset or physaddr, we move
         * it to hc-specific.
         */
        (void) nvlist_lookup_string(pa[npairs - 1], FM_FMRI_HC_NAME, &hcsn);
        if (strcmp(hcsn, FM_FMRI_HC_SPECIFIC_OFFSET) == 0 ||
            strcmp(hcsn, FM_FMRI_HC_SPECIFIC_PHYSADDR) == 0) {
                char *hcid;
                nvlist_t *hcsp;
                uint64_t val;

                (void) nvlist_lookup_string(pa[npairs - 1], FM_FMRI_HC_ID,
                    &hcid);
                val = strtoull(hcid, NULL, 16);
                if (topo_mod_nvalloc(mod, &hcsp, NV_UNIQUE_NAME) != 0)
                        goto hcfmbail;
                if (nvlist_add_uint64(hcsp, hcsn, val) != 0 ||
                    nvlist_add_nvlist(nf, FM_FMRI_HC_SPECIFIC, hcsp) != 0) {
                        nvlist_free(hcsp);
                        goto hcfmbail;
                }

                nvlist_free(hcsp);
                n--;
        }

        if ((e = nvlist_add_uint32(nf, FM_FMRI_HC_LIST_SZ, n)) == 0)
                e = nvlist_add_nvlist_array(nf, FM_FMRI_HC_LIST, pa, n);
        if (e != 0) {
                topo_mod_dprintf(mod, "construction of new hc nvl failed");
                goto hcfmbail;
        }

        /*
         * Clean-up
         */
        for (i = 0; i < npairs; i++)
                nvlist_free(pa[i]);
        topo_mod_free(mod, pa, npairs * sizeof (nvlist_t *));
        topo_mod_strfree(mod, serial);
        topo_mod_strfree(mod, part);
        topo_mod_strfree(mod, rev);
        nvlist_free(auth);

        if (make_facility(mod, str, &fac) == -1)
                goto hcfmbail;

        if (fac != NULL) {
                if (nvlist_add_nvlist(nf, FM_FMRI_FACILITY, fac) != 0)
                        goto hcfmbail;
        }

        *out = nf;

        return (0);

hcfmbail:
        nvlist_free(nf);
        for (i = 0; i < npairs; i++)
                nvlist_free(pa[i]);
        topo_mod_free(mod, pa, npairs * sizeof (nvlist_t *));

        topo_mod_strfree(mod, serial);
        topo_mod_strfree(mod, part);
        topo_mod_strfree(mod, rev);
        nvlist_free(auth);
        nvlist_free(nf);
        return (topo_mod_seterrno(mod, EMOD_FMRI_MALFORM));
}

static nvlist_t *
hc_list_create(topo_mod_t *mod, const char *name, char *inst)
{
        int err;
        nvlist_t *hc;

        if (topo_mod_nvalloc(mod, &hc, NV_UNIQUE_NAME) != 0)
                return (NULL);

        err = nvlist_add_string(hc, FM_FMRI_HC_NAME, name);
        err |= nvlist_add_string(hc, FM_FMRI_HC_ID, inst);
        if (err != 0) {
                nvlist_free(hc);
                return (NULL);
        }

        return (hc);
}

static nvlist_t *
hc_create_seterror(topo_mod_t *mod, nvlist_t **hcl, int n, nvlist_t *fmri,
    int err)
{
        int i;

        if (hcl != NULL) {
                for (i = 0; i < n + 1; ++i)
                        nvlist_free(hcl[i]);

                topo_mod_free(mod, hcl, sizeof (nvlist_t *) * (n + 1));
        }

        nvlist_free(fmri);

        (void) topo_mod_seterrno(mod, err);

        topo_mod_dprintf(mod, "unable to create hc FMRI: %s\n",
            topo_mod_errmsg(mod));

        return (NULL);
}

static int
hc_name_canonical(topo_mod_t *mod, const char *name)
{
        int i;

        if (getenv("NOHCCHECK") != NULL)
                return (1);

        /*
         * Only enumerate elements with correct canonical names
         */
        for (i = 0; i < hc_ncanon; i++) {
                if (strcmp(name, hc_canon[i].hcc_name) == 0)
                        break;
        }
        if (i >= hc_ncanon) {
                topo_mod_dprintf(mod, "non-canonical name %s\n",
                    name);
                return (0);
        } else {
                return (1);
        }
}

static nvlist_t *
hc_fmri_create(topo_mod_t *mod, nvlist_t *pfmri, int version, const char *name,
    topo_instance_t inst, const nvlist_t *auth, const char *part,
    const char *rev, const char *serial)
{
        int i;
        char str[21]; /* sizeof (UINT64_MAX) + '\0' */
        uint_t pelems = 0;
        nvlist_t **phcl = NULL;
        nvlist_t **hcl = NULL;
        nvlist_t *fmri = NULL;

        if (version > FM_HC_SCHEME_VERSION)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_VER_OLD));
        else if (version < FM_HC_SCHEME_VERSION)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_VER_NEW));

        /*
         * Check that the requested name is in our canonical list
         */
        if (hc_name_canonical(mod, name) == 0)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_NONCANON));
        /*
         * Copy the parent's HC_LIST
         */
        if (pfmri != NULL) {
                if (nvlist_lookup_nvlist_array(pfmri, FM_FMRI_HC_LIST,
                    &phcl, &pelems) != 0)
                        return (hc_create_seterror(mod,
                            hcl, pelems, fmri, EMOD_FMRI_MALFORM));
        }

        hcl = topo_mod_zalloc(mod, sizeof (nvlist_t *) * (pelems + 1));
        if (hcl == NULL)
                return (hc_create_seterror(mod,  hcl, pelems, fmri,
                    EMOD_NOMEM));

        for (i = 0; i < pelems; ++i)
                if (topo_mod_nvdup(mod, phcl[i], &hcl[i]) != 0)
                        return (hc_create_seterror(mod,
                            hcl, pelems, fmri, EMOD_FMRI_NVL));

        (void) snprintf(str, sizeof (str), "%d", inst);
        if ((hcl[i] = hc_list_create(mod, name, str)) == NULL)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_FMRI_NVL));

        if ((fmri = hc_base_fmri_create(mod, auth, part, rev, serial)) == NULL)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_FMRI_NVL));

        if (nvlist_add_nvlist_array(fmri, FM_FMRI_HC_LIST, hcl, pelems + 1)
            != 0)
                return (hc_create_seterror(mod,
                    hcl, pelems, fmri, EMOD_FMRI_NVL));

        if (hcl != NULL) {
                for (i = 0; i < pelems + 1; ++i) {
                        nvlist_free(hcl[i]);
                }
                topo_mod_free(mod, hcl, sizeof (nvlist_t *) * (pelems + 1));
        }

        return (fmri);
}

/*ARGSUSED*/
static int
hc_fmri_create_meth(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int ret;
        nvlist_t *args, *pfmri = NULL;
        nvlist_t *auth;
        uint64_t inst;
        char *name, *serial, *rev, *part;

        if (version > TOPO_METH_FMRI_VERSION)
                return (topo_mod_seterrno(mod, EMOD_VER_NEW));

        /* First the must-have fields */
        if (nvlist_lookup_string(in, TOPO_METH_FMRI_ARG_NAME, &name) != 0)
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        if (nvlist_lookup_uint64(in, TOPO_METH_FMRI_ARG_INST, &inst) != 0)
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));

        /*
         * args is optional
         */
        pfmri = NULL;
        auth = NULL;
        serial = rev = part = NULL;
        if ((ret = nvlist_lookup_nvlist(in, TOPO_METH_FMRI_ARG_NVL, &args))
            != 0) {
                if (ret != ENOENT)
                        return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        } else {

                /* And then optional arguments */
                (void) nvlist_lookup_nvlist(args, TOPO_METH_FMRI_ARG_PARENT,
                    &pfmri);
                (void) nvlist_lookup_nvlist(args, TOPO_METH_FMRI_ARG_AUTH,
                    &auth);
                (void) nvlist_lookup_string(args, TOPO_METH_FMRI_ARG_PART,
                    &part);
                (void) nvlist_lookup_string(args, TOPO_METH_FMRI_ARG_REV, &rev);
                (void) nvlist_lookup_string(args, TOPO_METH_FMRI_ARG_SER,
                    &serial);
        }

        *out = hc_fmri_create(mod, pfmri, version, name, inst, auth, part,
            rev, serial);
        if (*out == NULL)
                return (-1);
        return (0);
}

struct hc_walk {
        topo_mod_walk_cb_t hcw_cb;
        void *hcw_priv;
        topo_walk_t *hcw_wp;
        nvlist_t **hcw_list;
        nvlist_t *hcw_fmri;
        nvlist_t *hcw_fac;
        uint_t hcw_index;
        uint_t hcw_end;
};

/*
 * Returns true if the given node is beneath the specified FMRI.  This uses
 * the TOPO_METH_CONTAINS method, because some enumerators (such as external
 * enclosures) may want to do a comparison based on chassis WWN instead of the
 * instance ID.  If this comparison function fails or is not supported, then we
 * fall back to a direct name/instance comparison.
 */
static int
hc_match(topo_mod_t *mod, tnode_t *node, nvlist_t *fmri, const char *name,
    topo_instance_t inst, boolean_t *result)
{
        nvlist_t *rsrc;
        nvlist_t *arg, *nvl;
        uint32_t match = 0;
        int err;

        if (topo_node_resource(node, &rsrc, &err) != 0)
                return (-1);

        if (topo_mod_nvalloc(mod, &arg, NV_UNIQUE_NAME) != 0 ||
            nvlist_add_nvlist(arg, TOPO_METH_FMRI_ARG_FMRI,
            rsrc) != 0 ||
            nvlist_add_nvlist(arg, TOPO_METH_FMRI_ARG_SUBFMRI,
            fmri) != 0) {
                nvlist_free(rsrc);
                (void) topo_mod_seterrno(mod, EMOD_NOMEM);
                return (-1);
        }

        nvlist_free(rsrc);

        if (topo_method_invoke(node, TOPO_METH_CONTAINS,
            TOPO_METH_CONTAINS_VERSION, arg, &nvl, &err) != 0) {
                nvlist_free(arg);
                if (err == ETOPO_METHOD_NOTSUP) {
                        match = (strcmp(name,
                            topo_node_name(node)) == 0 &&
                            inst == topo_node_instance(node));
                } else {
                        return (-1);
                }
        } else {
                nvlist_free(arg);
                if (nvlist_lookup_uint32(nvl, TOPO_METH_CONTAINS_RET,
                    &match) != 0) {
                        nvlist_free(nvl);
                        (void) topo_mod_seterrno(mod, EMOD_NVL_INVAL);
                        return (-1);
                }
                nvlist_free(nvl);
        }

        *result = (match != 0);
        return (0);
}

/*
 * Ideally, we should just be able to call topo_walk_bysibling().  But that
 * code assumes that the name/instance pair will match, so we need to
 * explicitly iterate over children of the parent looking for a matching value.
 */
static int
hc_walk_sibling(topo_mod_t *mod, tnode_t *node, struct hc_walk *hwp,
    const char *name, topo_instance_t inst)
{
        tnode_t *pnp = topo_node_parent(node);
        topo_walk_t *wp = hwp->hcw_wp;
        tnode_t *np;
        boolean_t matched;
        int status;

        for (np = topo_child_first(pnp); np != NULL;
            np = topo_child_next(pnp, np)) {
                topo_node_hold(np);
                if (hc_match(mod, np, hwp->hcw_fmri, name, inst,
                    &matched) == 0 && matched) {
                        wp->tw_node = np;
                        if (wp->tw_mod != NULL)
                                status = wp->tw_cb(mod, np, hwp);
                        else
                                status = wp->tw_cb(wp->tw_thp, np, hwp);
                        topo_node_rele(np);
                        wp->tw_node = node;
                        return (status);
                }

                topo_node_rele(np);
        }

        return (TOPO_WALK_TERMINATE);
}

/*
 * Generic walker for the hc-scheme topo tree.  This function uses the
 * hierachical nature of the hc-scheme to efficiently step through
 * the topo hc tree.  Node lookups are done by topo_walk_byid() and
 * topo_walk_bysibling()  at each component level to avoid unnecessary
 * traversal of the tree.  hc_walker() never returns TOPO_WALK_NEXT, so
 * whether TOPO_WALK_CHILD or TOPO_WALK_SIBLING is specified by
 * topo_walk_step() doesn't affect the traversal.
 */
static int
hc_walker(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int i, err;
        struct hc_walk *hwp = (struct hc_walk *)pdata;
        char *name, *id;
        char *fname, *ftype;
        topo_instance_t inst;
        boolean_t match;

        i = hwp->hcw_index;
        if (i > hwp->hcw_end) {
                if (hwp->hcw_fac != NULL) {
                        if ((err = hwp->hcw_cb(mod, node, hwp->hcw_priv))
                            != 0) {
                                (void) topo_mod_seterrno(mod, err);
                                topo_mod_dprintf(mod, "hc_walker: callback "
                                    "failed: %s\n ", topo_mod_errmsg(mod));
                                return (TOPO_WALK_ERR);
                        }
                        topo_mod_dprintf(mod, "hc_walker: callback "
                            "complete: terminate walk\n");
                        return (TOPO_WALK_TERMINATE);
                } else {
                        topo_mod_dprintf(mod, "hc_walker: node not found\n");
                        return (TOPO_WALK_TERMINATE);
                }
        }

        err = nvlist_lookup_string(hwp->hcw_list[i], FM_FMRI_HC_NAME, &name);
        err |= nvlist_lookup_string(hwp->hcw_list[i], FM_FMRI_HC_ID, &id);

        if (err != 0) {
                (void) topo_mod_seterrno(mod, EMOD_NVL_INVAL);
                return (TOPO_WALK_ERR);
        }

        inst = atoi(id);

        /*
         * Check to see if our node matches the requested FMRI.  If it doesn't
         * (because the enumerator determines matching based on something other
         * than name/instance, or because we're at the first level below the
         * root), then iterate over siblings to find the matching node.
         */
        if (hc_match(mod, node, hwp->hcw_fmri, name, inst, &match) != 0)
                return (TOPO_WALK_ERR);

        if (!match)
                return (hc_walk_sibling(mod, node, hwp, name, inst));

        topo_mod_dprintf(mod, "hc_walker: walking node:%s=%" PRIu64 " for hc:"
            "%s=%" PRIu64 " at %d, end at %d \n", topo_node_name(node),
            topo_node_instance(node), name, inst, i, hwp->hcw_end);

        if (i == hwp->hcw_end) {

                /*
                 * We are at the end of the hc-list.  Now, check for
                 * a facility leaf and walk one more time.
                 */
                if (hwp->hcw_fac != NULL) {
                        err = nvlist_lookup_string(hwp->hcw_fac,
                            FM_FMRI_FACILITY_NAME, &fname);
                        err |= nvlist_lookup_string(hwp->hcw_fac,
                            FM_FMRI_FACILITY_TYPE, &ftype);
                        if (err != 0) {
                                (void) topo_mod_seterrno(mod, EMOD_NVL_INVAL);
                                return (TOPO_WALK_ERR);
                        }
                        hwp->hcw_index++;
                        topo_mod_dprintf(mod, "hc_walker: walk to facility "
                            "node:%s=%s\n", fname, ftype);
                        return (topo_walk_byid(hwp->hcw_wp, fname, 0));
                }

                /*
                 * Otherwise, this is the node we're looking for.
                 */
                if ((err = hwp->hcw_cb(mod, node, hwp->hcw_priv)) != 0) {
                        (void) topo_mod_seterrno(mod, err);
                        topo_mod_dprintf(mod, "hc_walker: callback "
                            "failed: %s\n ", topo_mod_errmsg(mod));
                        return (TOPO_WALK_ERR);
                } else {
                        topo_mod_dprintf(mod, "hc_walker: callback "
                            "complete: terminate walk\n");
                        return (TOPO_WALK_TERMINATE);
                }
        }

        /*
         * Move on to the next component in the hc-list
         */
        hwp->hcw_index = ++i;
        err = nvlist_lookup_string(hwp->hcw_list[i], FM_FMRI_HC_NAME, &name);
        err |= nvlist_lookup_string(hwp->hcw_list[i], FM_FMRI_HC_ID, &id);
        if (err != 0) {
                (void) topo_mod_seterrno(mod, err);
                return (TOPO_WALK_ERR);
        }
        inst = atoi(id);

        return (topo_walk_byid(hwp->hcw_wp, name, inst));

}

static struct hc_walk *
hc_walk_init(topo_mod_t *mod, tnode_t *node, nvlist_t *rsrc,
    topo_mod_walk_cb_t cb, void *pdata)
{
        int err, ret;
        uint_t sz;
        struct hc_walk *hwp;
        topo_walk_t *wp;

        if ((hwp = topo_mod_alloc(mod, sizeof (struct hc_walk))) == NULL) {
                (void) topo_mod_seterrno(mod, EMOD_NOMEM);
                return (NULL);
        }

        if (nvlist_lookup_nvlist_array(rsrc, FM_FMRI_HC_LIST, &hwp->hcw_list,
            &sz) != 0) {
                topo_mod_dprintf(mod, "hc_walk_init: failed to lookup %s "
                    "nvlist\n", FM_FMRI_HC_LIST);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
                (void) topo_mod_seterrno(mod, EMOD_METHOD_INVAL);
                return (NULL);
        }
        if ((ret = nvlist_lookup_nvlist(rsrc, FM_FMRI_FACILITY, &hwp->hcw_fac))
            != 0) {
                if (ret != ENOENT) {
                        topo_mod_dprintf(mod, "hc_walk_init: unexpected error "
                            "looking up %s nvlist", FM_FMRI_FACILITY);
                        topo_mod_free(mod, hwp, sizeof (struct hc_walk));
                        (void) topo_mod_seterrno(mod, EMOD_METHOD_INVAL);
                        return (NULL);
                } else {
                        hwp->hcw_fac = NULL;
                }
        }

        hwp->hcw_fmri = rsrc;
        hwp->hcw_end = sz - 1;
        hwp->hcw_index = 0;
        hwp->hcw_priv = pdata;
        hwp->hcw_cb = cb;
        if ((wp = topo_mod_walk_init(mod, node, hc_walker, (void *)hwp, &err))
            == NULL) {
                topo_mod_dprintf(mod, "hc_walk_init: topo_mod_walk_init failed "
                    "(%s)\n", topo_strerror(err));
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
                (void) topo_mod_seterrno(mod, err);
                return (NULL);
        }

        hwp->hcw_wp = wp;

        return (hwp);
}

struct prop_lookup {
        const char *pl_pgroup;
        const char *pl_pname;
        int pl_flag;
        nvlist_t *pl_args;
        nvlist_t *pl_rsrc;
        nvlist_t *pl_prop;
};

/*ARGSUSED*/
static int
hc_prop_get(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err = 0;

        struct prop_lookup *plp = (struct prop_lookup *)pdata;

        (void) topo_prop_getprop(node, plp->pl_pgroup, plp->pl_pname,
            plp->pl_args, &plp->pl_prop, &err);

        return (err);
}

static int
hc_fmri_prop_get(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct prop_lookup *plp;

        if (version > TOPO_METH_PROP_GET_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((plp = topo_mod_alloc(mod, sizeof (struct prop_lookup))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        err = nvlist_lookup_string(in, TOPO_PROP_GROUP,
            (char **)&plp->pl_pgroup);
        err |= nvlist_lookup_string(in, TOPO_PROP_VAL_NAME,
            (char **)&plp->pl_pname);
        err |= nvlist_lookup_nvlist(in, TOPO_PROP_RESOURCE, &plp->pl_rsrc);
        if (err != 0) {
                topo_mod_free(mod, plp, sizeof (struct prop_lookup));
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        }

        /*
         * Private args to prop method are optional
         */
        if ((err = nvlist_lookup_nvlist(in, TOPO_PROP_PARGS, &plp->pl_args))
            != 0) {
                if (err != ENOENT) {
                        topo_mod_free(mod, plp, sizeof (struct prop_lookup));
                        return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
                } else {
                        plp->pl_args = NULL;
                }
        }

        plp->pl_prop = NULL;
        if ((hwp = hc_walk_init(mod, node, plp->pl_rsrc, hc_prop_get,
            (void *)plp)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        if (plp->pl_prop != NULL)
                *out = plp->pl_prop;

        topo_mod_free(mod, plp, sizeof (struct prop_lookup));

        return (err);
}

/*ARGSUSED*/
static int
hc_pgrp_get(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err = 0;

        struct prop_lookup *plp = (struct prop_lookup *)pdata;

        (void) topo_prop_getpgrp(node, plp->pl_pgroup, &plp->pl_prop, &err);

        return (err);
}

static int
hc_fmri_pgrp_get(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct prop_lookup *plp;

        if (version > TOPO_METH_PGRP_GET_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((plp = topo_mod_alloc(mod, sizeof (struct prop_lookup))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        err = nvlist_lookup_string(in, TOPO_PROP_GROUP,
            (char **)&plp->pl_pgroup);
        err |= nvlist_lookup_nvlist(in, TOPO_PROP_RESOURCE, &plp->pl_rsrc);
        if (err != 0) {
                topo_mod_free(mod, plp, sizeof (struct prop_lookup));
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        }

        plp->pl_prop = NULL;
        if ((hwp = hc_walk_init(mod, node, plp->pl_rsrc, hc_pgrp_get,
            (void *)plp)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        if (plp->pl_prop != NULL)
                *out = plp->pl_prop;

        topo_mod_free(mod, plp, sizeof (struct prop_lookup));

        return (err);
}

/*ARGSUSED*/
static int
hc_prop_setprop(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err = 0;

        struct prop_lookup *plp = (struct prop_lookup *)pdata;

        (void) topo_prop_setprop(node, plp->pl_pgroup, plp->pl_prop,
            plp->pl_flag, plp->pl_args, &err);

        return (err);
}

/*ARGSUSED*/
static int
hc_fmri_prop_set(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct prop_lookup *plp;

        if (version > TOPO_METH_PROP_SET_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((plp = topo_mod_alloc(mod, sizeof (struct prop_lookup))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        err = nvlist_lookup_string(in, TOPO_PROP_GROUP,
            (char **)&plp->pl_pgroup);
        err |= nvlist_lookup_nvlist(in, TOPO_PROP_RESOURCE, &plp->pl_rsrc);
        err |= nvlist_lookup_nvlist(in, TOPO_PROP_VAL, &plp->pl_prop);
        err |= nvlist_lookup_int32(in, TOPO_PROP_FLAG, &plp->pl_flag);
        if (err != 0) {
                topo_mod_free(mod, plp, sizeof (struct prop_lookup));
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        }

        /*
         * Private args to prop method are optional
         */
        if ((err = nvlist_lookup_nvlist(in, TOPO_PROP_PARGS, &plp->pl_args))
            != 0) {
                if (err != ENOENT)
                        return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
                else
                        plp->pl_args = NULL;
        }

        if ((hwp = hc_walk_init(mod, node, plp->pl_rsrc, hc_prop_setprop,
            (void *)plp)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        topo_mod_free(mod, plp, sizeof (struct prop_lookup));

        return (err);
}

struct hc_args {
        nvlist_t *ha_fmri;
        nvlist_t *ha_nvl;
        char *ha_method_name;
        topo_version_t ha_method_ver;
};

static int
hc_auth_changed(nvlist_t *nva, nvlist_t *nvb, const char *propname)
{
        char *stra, *strb;

        if (nvlist_lookup_string(nva, propname, &stra) != 0 ||
            nvlist_lookup_string(nvb, propname, &strb) != 0)
                return (FMD_OBJ_STATE_UNKNOWN);

        if (strcmp(stra, strb) != 0)
                return (FMD_OBJ_STATE_REPLACED);
        else
                return (FMD_OBJ_STATE_STILL_PRESENT);
}

static int
hc_is_present(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err;
        struct hc_args *hap = (struct hc_args *)pdata;
        nvlist_t *rsrc;
        boolean_t present;

        /*
         * check with the enumerator that created this FMRI
         * (topo node)
         */
        if (topo_method_invoke(node, TOPO_METH_PRESENT,
            TOPO_METH_PRESENT_VERSION, hap->ha_fmri, &hap->ha_nvl,
            &err) < 0) {

                /*
                 * If the method exists but failed for some other reason,
                 * propagate the error as making any decision over presence is
                 * impossible.
                 */
                if (err != ETOPO_METHOD_NOTSUP)
                        return (err);

                /*
                 * Check the authority information.  If the part id or serial
                 * number doesn't match, then it isn't the same FMRI.
                 * Otherwise, assume presence.
                 */
                if (topo_node_resource(node, &rsrc, &err) != 0)
                        return (err);

                present = B_TRUE;
                if (hc_auth_changed(hap->ha_fmri, rsrc,
                    FM_FMRI_HC_SERIAL_ID) == FMD_OBJ_STATE_REPLACED ||
                    hc_auth_changed(hap->ha_fmri, rsrc,
                    FM_FMRI_HC_PART) == FMD_OBJ_STATE_REPLACED) {
                        present = B_FALSE;
                }
                nvlist_free(rsrc);

                if (topo_mod_nvalloc(mod, &hap->ha_nvl, NV_UNIQUE_NAME) != 0)
                        return (EMOD_NOMEM);

                if (nvlist_add_uint32(hap->ha_nvl,
                    TOPO_METH_PRESENT_RET, present) != 0) {
                        nvlist_free(hap->ha_nvl);
                        hap->ha_nvl = NULL;
                        return (EMOD_NOMEM);
                }
        }

        return (0);
}

static int
hc_fmri_present(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct hc_args *hap;

        if (version > TOPO_METH_PRESENT_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((hap = topo_mod_alloc(mod, sizeof (struct hc_args))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        hap->ha_fmri = in;
        hap->ha_nvl = NULL;
        if ((hwp = hc_walk_init(mod, node, hap->ha_fmri, hc_is_present,
            (void *)hap)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        if (hap->ha_nvl != NULL)
                *out = hap->ha_nvl;

        topo_mod_free(mod, hap, sizeof (struct hc_args));

        return (err);
}

static int
hc_is_replaced(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err;
        struct hc_args *hap = (struct hc_args *)pdata;
        uint32_t present = 0;
        nvlist_t *rsrc;
        uint32_t rval = FMD_OBJ_STATE_UNKNOWN;

        /*
         * check with the enumerator that created this FMRI
         * (topo node)
         */
        if (topo_method_invoke(node, TOPO_METH_REPLACED,
            TOPO_METH_REPLACED_VERSION, hap->ha_fmri, &hap->ha_nvl,
            &err) < 0) {
                /*
                 * If the method exists but failed for some other
                 * reason, propagate the error as making any decision
                 * over presence is impossible.
                 */
                if (err != ETOPO_METHOD_NOTSUP)
                        return (err);

                /*
                 * Enumerator didn't provide "replaced" method -
                 * try "present" method
                 */
                if (topo_method_invoke(node, TOPO_METH_PRESENT,
                    TOPO_METH_PRESENT_VERSION, hap->ha_fmri, &hap->ha_nvl,
                    &err) < 0) {
                        /*
                         * If the method exists but failed for some other
                         * reason, propagate the error as making any decision
                         * over presence is impossible.
                         */
                        if (err != ETOPO_METHOD_NOTSUP)
                                return (err);

                        /*
                         * Enumerator didn't provide "present" method either -
                         * so check the authority information.  If the part id
                         * or serial number doesn't match, then it isn't the
                         * same FMRI. Otherwise, if we have a serial number and
                         * it hasn't changed, then assume it is the same FMRI.
                         */
                        if (topo_node_resource(node, &rsrc, &err) != 0)
                                return (err);
                        rval = hc_auth_changed(hap->ha_fmri, rsrc,
                            FM_FMRI_HC_PART);
                        if (rval != FMD_OBJ_STATE_REPLACED)
                                rval = hc_auth_changed(hap->ha_fmri, rsrc,
                                    FM_FMRI_HC_SERIAL_ID);
                        nvlist_free(rsrc);
                        if (topo_mod_nvalloc(mod, &hap->ha_nvl,
                            NV_UNIQUE_NAME) != 0)
                                return (EMOD_NOMEM);
                        if (nvlist_add_uint32(hap->ha_nvl,
                            TOPO_METH_REPLACED_RET, rval) != 0) {
                                nvlist_free(hap->ha_nvl);
                                hap->ha_nvl = NULL;
                                return (ETOPO_PROP_NVL);
                        }
                } else {
                        (void) nvlist_lookup_uint32(hap->ha_nvl,
                            TOPO_METH_PRESENT_RET, &present);
                        (void) nvlist_remove(hap->ha_nvl,
                            TOPO_METH_PRESENT_RET, DATA_TYPE_UINT32);
                        if (nvlist_add_uint32(hap->ha_nvl,
                            TOPO_METH_REPLACED_RET,
                            present ? FMD_OBJ_STATE_UNKNOWN :
                            FMD_OBJ_STATE_NOT_PRESENT) != 0) {
                                nvlist_free(hap->ha_nvl);
                                hap->ha_nvl = NULL;
                                return (ETOPO_PROP_NVL);
                        }
                }
        }
        return (0);
}

static int
hc_fmri_replaced(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct hc_args *hap;

        if (version > TOPO_METH_REPLACED_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((hap = topo_mod_alloc(mod, sizeof (struct hc_args))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        hap->ha_fmri = in;
        hap->ha_nvl = NULL;
        if ((hwp = hc_walk_init(mod, node, hap->ha_fmri, hc_is_replaced,
            (void *)hap)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        if (hap->ha_nvl != NULL)
                *out = hap->ha_nvl;

        topo_mod_free(mod, hap, sizeof (struct hc_args));

        return (err);
}

static int
hc_unusable(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err;
        struct hc_args *hap = (struct hc_args *)pdata;

        /*
         * check with the enumerator that created this FMRI
         * (topo node)
         */
        if (topo_method_invoke(node, TOPO_METH_UNUSABLE,
            TOPO_METH_UNUSABLE_VERSION, hap->ha_fmri, &hap->ha_nvl,
            &err) < 0) {

                /*
                 * Err on the side of caution and return usable
                 */
                if (topo_mod_nvalloc(mod, &hap->ha_nvl, NV_UNIQUE_NAME) == 0)
                        if (nvlist_add_uint32(hap->ha_nvl,
                            TOPO_METH_UNUSABLE_RET, 0) == 0)
                                return (0);

                return (ETOPO_PROP_NVL);
        }

        return (0);
}

static int
hc_fmri_unusable(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct hc_args *hap;

        if (version > TOPO_METH_UNUSABLE_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((hap = topo_mod_alloc(mod, sizeof (struct hc_args))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        hap->ha_fmri = in;
        hap->ha_nvl = NULL;
        if ((hwp = hc_walk_init(mod, node, hap->ha_fmri, hc_unusable,
            (void *)hap)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                err = -1;
        }

        if (hap->ha_nvl != NULL)
                *out = hap->ha_nvl;

        topo_mod_free(mod, hap, sizeof (struct hc_args));

        return (err);
}

struct fac_lookup {
        const char *fl_fac_type;
        uint32_t fl_fac_subtype;
#ifdef _LP64
        uint64_t fl_callback;
        uint64_t fl_callback_args;
#else
        uint32_t fl_callback;
        uint32_t fl_callback_args;
#endif
        nvlist_t *fl_rsrc;
        nvlist_t *fl_fac_rsrc;
};

static int
hc_fac_get(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        struct fac_lookup *flp = (struct fac_lookup *)pdata;
        topo_walk_cb_t cb = (topo_walk_cb_t)flp->fl_callback;
        topo_faclist_t faclist, *tmp;
        int err, ret = 0;

        /*
         * Lookup the specified facility node.  Return with an error if we can't
         * find it.
         */
        if (topo_node_facility(mod->tm_hdl, node, flp->fl_fac_type,
            flp->fl_fac_subtype, &faclist, &err) != 0) {
                topo_mod_dprintf(mod, "hc_fac_get: topo_node_facility "
                    "failed\n");
                return (TOPO_WALK_ERR);
        }

        /*
         * Invoke user's callback for each facility node in the topo list,
         * passing in a pointer to the facility node
         */
        for (tmp = topo_list_next(&faclist.tf_list); tmp != NULL;
            tmp = topo_list_next(tmp)) {

                if ((err = cb(mod->tm_hdl, tmp->tf_node,
                    (void *)flp->fl_callback_args)) != 0) {
                        (void) topo_mod_seterrno(mod, err);
                        topo_mod_dprintf(mod, "hc_fac_get: callback failed: "
                            "%s\n ", topo_mod_errmsg(mod));
                        ret = TOPO_WALK_ERR;
                        break;
                }
        }

        while ((tmp = topo_list_next(&faclist.tf_list)) != NULL) {
                topo_list_delete(&faclist.tf_list, tmp);
                topo_mod_free(mod, tmp, sizeof (topo_faclist_t));
        }
        return (ret);
}

static int
hc_fmri_facility(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err = 0;
        struct hc_walk *hwp;
        struct fac_lookup *flp;

        if (version > TOPO_METH_FACILITY_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((flp = topo_mod_alloc(mod, sizeof (struct fac_lookup))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        /*
         * lookup arguments: hw resource, facility type, facility subtype,
         *  callback and callback args
         */
        err = nvlist_lookup_nvlist(in, TOPO_PROP_RESOURCE, &flp->fl_rsrc);
        err |= nvlist_lookup_string(in, FM_FMRI_FACILITY_TYPE,
            (char **)&flp->fl_fac_type);
        err |= nvlist_lookup_uint32(in, "type", &flp->fl_fac_subtype);
#ifdef _LP64
        err |= nvlist_lookup_uint64(in, "callback", &flp->fl_callback);
        err |= nvlist_lookup_uint64(in, "callback-args",
            &flp->fl_callback_args);
#else
        err |= nvlist_lookup_uint32(in, "callback", &flp->fl_callback);
        err |= nvlist_lookup_uint32(in, "callback-args",
            &flp->fl_callback_args);
#endif
        if (err != 0) {
                topo_mod_dprintf(mod, "hc_fmri_facility: failed to construct "
                    "walker arg nvlist\n");
                topo_mod_free(mod, flp, sizeof (struct fac_lookup));
                return (topo_mod_seterrno(mod, EMOD_METHOD_INVAL));
        }

        flp->fl_fac_rsrc = NULL;
        if ((hwp = hc_walk_init(mod, node, flp->fl_rsrc, hc_fac_get,
            (void *)flp)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
                topo_mod_free(mod, hwp, sizeof (struct hc_walk));
        } else {
                topo_mod_dprintf(mod, "hc_fmri_facility: failed to initialize "
                    "hc walker\n");
                err = -1;
        }

        if (flp->fl_fac_rsrc != NULL)
                *out = flp->fl_fac_rsrc;

        topo_mod_free(mod, flp, sizeof (struct fac_lookup));

        return (err);
}

/* ARGSUSED */
static int
hc_expand(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err;
        nvlist_t *nvl;
        const char **namep;
        struct hc_args *hap = (struct hc_args *)pdata;
        const char *names[] = {
                FM_FMRI_HC_SERIAL_ID,
                FM_FMRI_HC_PART,
                FM_FMRI_HC_REVISION,
                NULL
        };

        if (topo_node_resource(node, &nvl, &err) != 0)
                return (ETOPO_METHOD_FAIL);

        for (namep = names; *namep != NULL; namep++) {
                char *in_val, *node_val;

                if (nvlist_lookup_string(nvl, *namep, &node_val) != 0)
                        continue;

                if (nvlist_lookup_string(hap->ha_fmri, *namep, &in_val) == 0) {
                        if (strcmp(in_val, node_val) == 0)
                                continue;
                        (void) nvlist_remove(hap->ha_fmri, *namep,
                            DATA_TYPE_STRING);
                }

                if (nvlist_add_string(hap->ha_fmri, *namep, node_val) != 0) {
                        nvlist_free(nvl);
                        return (ETOPO_PROP_NVL);
                }
        }
        nvlist_free(nvl);

        return (0);
}

/* ARGSUSED */
static int
hc_fmri_expand(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct hc_args *hap;

        if (version > TOPO_METH_EXPAND_VERSION)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((hap = topo_mod_alloc(mod, sizeof (struct hc_args))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        hap->ha_fmri = in;
        hap->ha_nvl = NULL;
        if ((hwp = hc_walk_init(mod, node, hap->ha_fmri, hc_expand,
            (void *)hap)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
        } else {
                err = -1;
        }

        topo_mod_free(mod, hwp, sizeof (struct hc_walk));

        /* expand method should not return out nvlist */
        assert(hap->ha_nvl == NULL);

        topo_mod_free(mod, hap, sizeof (struct hc_args));

        return (err);
}

static int
hc_retire_subr(topo_mod_t *mod, tnode_t *node, void *pdata)
{
        int err, rc;
        struct hc_args *hap = (struct hc_args *)pdata;

        topo_mod_dprintf(mod, "hc_retire_subr: invoking method %s\n",
            hap->ha_method_name);
        /*
         * check with the enumerator that created this FMRI
         * (topo node)
         */
        rc = topo_method_invoke(node, hap->ha_method_name,
            hap->ha_method_ver, hap->ha_fmri, &hap->ha_nvl, &err);

        topo_mod_dprintf(mod, "hc_retire_subr: invoking method %s "
            "returned %d\n", hap->ha_method_name, rc);

        return (rc < 0 ? err : 0);
}

static int
hc_fmri_retire_subr(topo_mod_t *mod, tnode_t *node, char *method_name,
    topo_version_t builtin_version, topo_version_t version, nvlist_t *in,
    nvlist_t **out)
{
        int err;
        struct hc_walk *hwp;
        struct hc_args *hap;

        if (version > builtin_version)
                return (topo_mod_seterrno(mod, ETOPO_METHOD_VERNEW));

        if ((hap = topo_mod_alloc(mod, sizeof (struct hc_args))) == NULL)
                return (topo_mod_seterrno(mod, EMOD_NOMEM));

        hap->ha_fmri = in;
        hap->ha_nvl = NULL;
        hap->ha_method_name = method_name;
        hap->ha_method_ver = version;
        if ((hwp = hc_walk_init(mod, node, hap->ha_fmri, hc_retire_subr,
            (void *)hap)) != NULL) {
                if (topo_walk_step(hwp->hcw_wp, TOPO_WALK_CHILD) ==
                    TOPO_WALK_ERR)
                        err = -1;
                else
                        err = 0;
                topo_walk_fini(hwp->hcw_wp);
        } else {
                err = -1;
        }

        topo_mod_free(mod, hwp, sizeof (struct hc_walk));

        if (hap->ha_nvl != NULL)
                *out = hap->ha_nvl;

        topo_mod_free(mod, hap, sizeof (struct hc_args));

        return (err);
}

static int
hc_fmri_retire(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        return (hc_fmri_retire_subr(mod, node, TOPO_METH_RETIRE,
            TOPO_METH_RETIRE_VERSION, version, in, out));
}

static int
hc_fmri_unretire(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        return (hc_fmri_retire_subr(mod, node, TOPO_METH_UNRETIRE,
            TOPO_METH_UNRETIRE_VERSION, version, in, out));
}

static int
hc_fmri_service_state(topo_mod_t *mod, tnode_t *node, topo_version_t version,
    nvlist_t *in, nvlist_t **out)
{
        return (hc_fmri_retire_subr(mod, node, TOPO_METH_SERVICE_STATE,
            TOPO_METH_SERVICE_STATE_VERSION, version, in, out));
}