common/mdesc/mdesc_init_intern.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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/param.h>
#include <sys/mdesc.h>
#include <sys/mdesc_impl.h>

md_t *
md_init_intern(uint64_t *ptr,  void *(*allocp)(size_t),
        void (*freep)(void *, size_t))
{
    md_impl_t   *mdp;
    int     idx;
    int     count;
    int     done;
    uint64_t    gen;
    mde_str_cookie_t root_name;

    /*
     * Very basic checkup for alignment to avoid
     * bus error issues.
     */
    if ((((uintptr_t)ptr) & 7) != 0)
        return (NULL);

    mdp = (md_impl_t *)allocp(sizeof (md_impl_t));

    if (mdp == NULL)
        return (NULL);

    mdp->allocp = allocp;
    mdp->freep = freep;

    mdp->caddr = (char *)ptr;

    /*
     * setup internal structures
     */

    mdp->headerp = (md_header_t *)mdp->caddr;

    if (mdtoh32(mdp->headerp->transport_version) != MD_TRANSPORT_VERSION) {
        goto cleanup_nohash;
    }

    mdp->node_blk_size = mdtoh32(mdp->headerp->node_blk_sz);
    mdp->name_blk_size = mdtoh32(mdp->headerp->name_blk_sz);
    mdp->data_blk_size = mdtoh32(mdp->headerp->data_blk_sz);

    mdp->size = MD_HEADER_SIZE + mdp->node_blk_size +
        mdp->name_blk_size + mdp->data_blk_size;

    mdp->mdep = (md_element_t *)(mdp->caddr + MD_HEADER_SIZE);
    mdp->namep = (char *)(mdp->caddr + MD_HEADER_SIZE + mdp->node_blk_size);
    mdp->datap = (uint8_t *)(mdp->caddr + MD_HEADER_SIZE +
        mdp->name_blk_size + mdp->node_blk_size);

    mdp->root_node = MDE_INVAL_ELEM_COOKIE;


    /*
     * Should do a lot more sanity checking here.
     */

    /*
     * Should initialize a name hash here if we intend to use one
     */

    /*
     * Setup to find the root node
     */
    root_name = md_find_name((md_t *)mdp, "root");
    if (root_name == MDE_INVAL_STR_COOKIE) {
        goto cleanup;
    }

    /*
     * One more property we need is the count of nodes in the
     * DAG, not just the number of elements.
     *
     * We try and pickup the root node along the way here.
     */

    for (done = 0, idx = 0, count = 0; !done; ) {
        md_element_t *np;

        np = &(mdp->mdep[idx]);

        switch (MDE_TAG(np)) {
        case MDET_LIST_END:
            done = 1;
            break;

        case MDET_NODE:
            if (root_name == MDE_NAME(np)) {
                if (mdp->root_node != MDE_INVAL_ELEM_COOKIE) {
                    /* Gah .. more than one root */
                    goto cleanup;
                }
                mdp->root_node = (mde_cookie_t)idx;
            }
            idx = MDE_PROP_INDEX(np);
            count++;
            break;

        default:
            idx++;  /* ignore */
        }
    }

    /*
     * Ensure there is a root node
     */
    if (mdp->root_node == MDE_INVAL_ELEM_COOKIE) {
        goto cleanup;
    }

    /*
     * Register the counts
     */

    mdp->element_count = idx + 1;   /* include LIST_END */
    mdp->node_count = count;

    /*
     * Final sanity check that everything adds up
     */
    if (mdp->element_count != (mdp->node_blk_size / MD_ELEMENT_SIZE))
        goto cleanup;

    mdp->md_magic = LIBMD_MAGIC;

    /*
     * Setup MD generation
     */
    if (md_get_prop_val((md_t *)mdp, mdp->root_node,
        "md-generation#", &gen) != 0)
        mdp->gen = MDESC_INVAL_GEN;
    else
        mdp->gen = gen;

    return ((md_t *)mdp);

cleanup:
    /*
     * Clean up here - including a name hash if
     * we build one.
     */

cleanup_nohash:
    mdp->freep(mdp, sizeof (md_impl_t));
    return (NULL);
}