/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Active walks are tracked using a WCB (Walk Control Block), which is a simple
 * data structure that contains the mdb_walk_state_t passed to the various
 * walker functions for this particular walk, as well as links to other walk
 * layers if this is a layered walk.  The control block is kept in a list
 * associated with the MDB frame, so that we can clean up all the walks and
 * call their respective fini routines at the end of command processing.
 */

#include <mdb/mdb_module.h>
#include <mdb/mdb_modapi.h>
#include <mdb/mdb_debug.h>
#include <mdb/mdb_frame.h>
#include <mdb/mdb_err.h>
#include <mdb/mdb_wcb.h>
#include <mdb/mdb.h>

mdb_wcb_t *
mdb_wcb_from_state(mdb_walk_state_t *wsp)
{
        /*
         * The walk state passed to a walker sits at the start of the
         * walk control block, so we can ask the walker to pass this
         * back to us and quickly obtain the control block:
         */
        mdb_wcb_t *wcb = (mdb_wcb_t *)wsp;

        if (wcb->w_buftag != WCB_TAG_ACTIVE && wcb->w_buftag != WCB_TAG_INITIAL)
                fail("walk state %p is corrupt or not active\n", (void *)wcb);

        return (wcb);
}

mdb_wcb_t *
mdb_wcb_create(mdb_iwalker_t *iwp, mdb_walk_cb_t cb, void *data, uintptr_t addr)
{
        mdb_wcb_t *wcb = mdb_zalloc(sizeof (mdb_wcb_t), UM_SLEEP);

        wcb->w_buftag = WCB_TAG_INITIAL;
        wcb->w_walker = iwp;

        wcb->w_state.walk_callback = cb;
        wcb->w_state.walk_cbdata = data;
        wcb->w_state.walk_addr = addr;
        wcb->w_state.walk_arg = iwp->iwlk_init_arg;

        return (wcb);
}

void
mdb_wcb_destroy(mdb_wcb_t *wcb)
{
        mdb_wcb_t *p, *q;

        for (p = wcb->w_lyr_head; p != NULL; p = q) {
                q = wcb->w_lyr_link;
                mdb_wcb_destroy(p);
        }

        if (wcb->w_inited)
                wcb->w_walker->iwlk_fini(&wcb->w_state);

        mdb_free(wcb, sizeof (mdb_wcb_t));
}

void
mdb_wcb_insert(mdb_wcb_t *wcb, mdb_frame_t *fp)
{
        mdb_dprintf(MDB_DBG_WALK, "activate walk %s`%s wcb %p\n",
            wcb->w_walker->iwlk_modp->mod_name,
            wcb->w_walker->iwlk_name, (void *)wcb);

        wcb->w_buftag = WCB_TAG_ACTIVE;
        wcb->w_link = fp->f_wcbs;
        fp->f_wcbs = wcb;
}

void
mdb_wcb_delete(mdb_wcb_t *wcb, mdb_frame_t *fp)
{
        mdb_wcb_t **pp = &fp->f_wcbs;
        mdb_wcb_t *w;

        mdb_dprintf(MDB_DBG_WALK, "deactivate walk %s`%s wcb %p\n",
            wcb->w_walker->iwlk_modp->mod_name,
            wcb->w_walker->iwlk_name, (void *)wcb);

        for (w = fp->f_wcbs; w != NULL; pp = &w->w_link, w = w->w_link) {
                if (w == wcb) {
                        w->w_buftag = WCB_TAG_PASSIVE;
                        *pp = w->w_link;
                        return;
                }
        }

        fail("attempted to remove wcb not on list: %p\n", (void *)wcb);
}

void
mdb_wcb_purge(mdb_wcb_t **wcbpp)
{
        mdb_wcb_t *n, *wcb = *wcbpp;

        while (wcb != NULL) {
                mdb_dprintf(MDB_DBG_WALK, "purge walk %s`%s wcb %p\n",
                    wcb->w_walker->iwlk_modp->mod_name,
                    wcb->w_walker->iwlk_name, (void *)wcb);

                n = wcb->w_link;
                mdb_wcb_destroy(wcb);
                wcb = n;
        }

        *wcbpp = NULL;
}