/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "rcm_impl.h"
#include "rcm_module.h"

/*
 * Short-circuits unloading of modules with no registrations, so that
 * they are present during the next db_sync cycle.
 */
#define MOD_REFCNT_INIT         2

int need_cleanup;       /* flag indicating if clean up is needed */

static mutex_t mod_lock;        /* protects module list */
static module_t *module_head;   /* linked list of modules */
static rsrc_node_t *rsrc_root;  /* root of all resources */

/*
 * Misc help routines
 */
static void rcmd_db_print();
static void rcm_handle_free(rcm_handle_t *);
static rcm_handle_t *rcm_handle_alloc(module_t *);
static void rsrc_clients_free(client_t *);
static struct rcm_mod_ops *modops_from_v1(void *);
static int call_getinfo(struct rcm_mod_ops *, rcm_handle_t *, char *, id_t,
    uint_t, char **, char **, nvlist_t *, rcm_info_t **);
static int node_action(rsrc_node_t *, void *);

extern void start_polling_thread();

/*
 * translate /dev name to a /devices path
 *
 * N.B. This routine can be enhanced to understand network names
 *      and friendly names in the future.
 */
char *
resolve_name(char *alias)
{
        char *tmp;
        const char *dev = "/dev/";

        if (strlen(alias) == 0)
                return (NULL);

        if (strncmp(alias, dev, strlen(dev)) == 0) {
                /*
                 * Treat /dev/... as a symbolic link
                 */
                tmp = s_malloc(PATH_MAX);
                if (realpath(alias, tmp) != NULL) {
                        return (tmp);
                } else {
                        free(tmp);
                }
                /* Fail to resolve /dev/ name, use the name as is */
        }

        return (s_strdup(alias));
}

/*
 * Figure out resource type based on "resolved" name
 *
 * N.B. This routine does not figure out file system mount points.
 *      This is determined at runtime when filesys module register
 *      with RCM_FILESYS flag.
 */
int
rsrc_get_type(const char *resolved_name)
{
        if (resolved_name[0] != '/')
                return (RSRC_TYPE_ABSTRACT);

        if (strncmp("/devices/", resolved_name, 9) == 0)
                return (RSRC_TYPE_DEVICE);

        return (RSRC_TYPE_NORMAL);
}

/*
 * Module operations:
 *      module_load, module_unload, module_info, module_attach, module_detach,
 *      cli_module_hold, cli_module_rele
 */

#ifdef  ENABLE_MODULE_DETACH
/*
 * call unregister() entry point to allow module to unregister for
 * resources without getting confused.
 */
static void
module_detach(module_t *module)
{
        struct rcm_mod_ops *ops = module->modops;

        rcm_log_message(RCM_TRACE2, "module_detach(name=%s)\n", module->name);

        ops->rcmop_unregister(module->rcmhandle);
}
#endif  /* ENABLE_MODULE_DETACH */

/*
 * call register() entry point to allow module to register for resources
 */
static void
module_attach(module_t *module)
{
        struct rcm_mod_ops *ops = module->modops;

        rcm_log_message(RCM_TRACE2, "module_attach(name=%s)\n", module->name);

        if (ops->rcmop_register(module->rcmhandle) != RCM_SUCCESS) {
                rcm_log_message(RCM_WARNING,
                    gettext("module %s register() failed\n"), module->name);
        }
}

struct rcm_mod_ops *
module_init(module_t *module)
{
        if (module->dlhandle)
                /* rcm module */
                return (module->init());
        else
                /* rcm script */
                return (script_init(module));
}

/*
 * call rmc_mod_info() entry of module
 */
static const char *
module_info(module_t *module)
{
        if (module->dlhandle)
                /* rcm module */
                return (module->info());
        else
                /* rcm script */
                return (script_info(module));
}

int
module_fini(module_t *module)
{
        if (module->dlhandle)
                /* rcm module */
                return (module->fini());
        else
                /* rcm script */
                return (script_fini(module));
}

/*
 * call rmc_mod_fini() entry of module, dlclose module, and free memory
 */
static void
module_unload(module_t *module)
{
        int version = module->modops->version;

        rcm_log_message(RCM_DEBUG, "module_unload(name=%s)\n", module->name);

        (void) module_fini(module);

        rcm_handle_free(module->rcmhandle);
        free(module->name);

        switch (version) {
        case RCM_MOD_OPS_V1:
                /*
                 * Free memory associated with converted ops vector
                 */
                free(module->modops);
                break;

        case RCM_MOD_OPS_VERSION:
        default:
                break;
        }

        if (module->dlhandle)
                rcm_module_close(module->dlhandle);

        free(module);
}

/*
 * Locate the module, execute rcm_mod_init() and check ops vector version
 */
static module_t *
module_load(char *modname)
{
        module_t *module;

        rcm_log_message(RCM_DEBUG, "module_load(name=%s)\n", modname);

        /*
         * dlopen the module
         */
        module = s_calloc(1, sizeof (*module));
        module->name = s_strdup(modname);
        module->modops = NULL;
        rcm_init_queue(&module->client_q);

        if (rcm_is_script(modname) == 0) {
                /* rcm module */
                module->dlhandle = rcm_module_open(modname);

                if (module->dlhandle == NULL) {
                        rcm_log_message(RCM_NOTICE,
                            gettext("cannot open module %s\n"), modname);
                        goto fail;
                }

                /*
                 * dlsym rcm_mod_init/fini/info() entry points
                 */
                module->init = (struct rcm_mod_ops *(*)())dlsym(
                    module->dlhandle, "rcm_mod_init");
                module->fini = (int (*)())dlsym(
                    module->dlhandle, "rcm_mod_fini");
                module->info = (const char *(*)())dlsym(module->dlhandle,
                    "rcm_mod_info");
                if (module->init == NULL || module->fini == NULL ||
                    module->info == NULL) {
                        rcm_log_message(RCM_ERROR,
                            gettext("missing entries in module %s\n"), modname);
                        goto fail;
                }

        } else {
                /* rcm script */
                module->dlhandle = NULL;
                module->init = (struct rcm_mod_ops *(*)()) NULL;
                module->fini = (int (*)()) NULL;
                module->info = (const char *(*)()) NULL;
        }

        if ((module->modops = module_init(module)) == NULL) {
                if (module->dlhandle)
                        rcm_log_message(RCM_ERROR,
                            gettext("cannot init module %s\n"), modname);
                goto fail;
        }

        /*
         * Check ops vector version
         */
        switch (module->modops->version) {
        case RCM_MOD_OPS_V1:
                module->modops = modops_from_v1((void *)module->modops);
                break;

        case RCM_MOD_OPS_VERSION:
                break;

        default:
                rcm_log_message(RCM_ERROR,
                    gettext("module %s rejected: version %d not supported\n"),
                    modname, module->modops->version);
                (void) module_fini(module);
                goto fail;
        }

        /*
         * Make sure all fields are set
         */
        if ((module->modops->rcmop_register == NULL) ||
            (module->modops->rcmop_unregister == NULL) ||
            (module->modops->rcmop_get_info == NULL) ||
            (module->modops->rcmop_request_suspend == NULL) ||
            (module->modops->rcmop_notify_resume == NULL) ||
            (module->modops->rcmop_request_offline == NULL) ||
            (module->modops->rcmop_notify_online == NULL) ||
            (module->modops->rcmop_notify_remove == NULL)) {
                rcm_log_message(RCM_ERROR,
                    gettext("module %s rejected: has NULL ops fields\n"),
                    modname);
                (void) module_fini(module);
                goto fail;
        }

        module->rcmhandle = rcm_handle_alloc(module);
        return (module);

fail:
        if (module->modops && module->modops->version == RCM_MOD_OPS_V1)
                free(module->modops);

        if (module->dlhandle)
                rcm_module_close(module->dlhandle);

        free(module->name);
        free(module);
        return (NULL);
}

/*
 * add one to module hold count. load the module if not loaded
 */
static module_t *
cli_module_hold(char *modname)
{
        module_t *module;

        rcm_log_message(RCM_TRACE3, "cli_module_hold(%s)\n", modname);

        (void) mutex_lock(&mod_lock);
        module = module_head;
        while (module) {
                if (strcmp(module->name, modname) == 0) {
                        break;
                }
                module = module->next;
        }

        if (module) {
                module->ref_count++;
                (void) mutex_unlock(&mod_lock);
                return (module);
        }

        /*
         * Module not found, attempt to load it
         */
        if ((module = module_load(modname)) == NULL) {
                (void) mutex_unlock(&mod_lock);
                return (NULL);
        }

        /*
         * Hold module and link module into module list
         */
        module->ref_count = MOD_REFCNT_INIT;
        module->next = module_head;
        module_head = module;

        (void) mutex_unlock(&mod_lock);

        return (module);
}

/*
 * decrement module hold count. Unload it if no reference
 */
static void
cli_module_rele(module_t *module)
{
        module_t *curr = module_head, *prev = NULL;

        rcm_log_message(RCM_TRACE3, "cli_module_rele(name=%s)\n", module->name);

        (void) mutex_lock(&mod_lock);
        if (--(module->ref_count) != 0) {
                (void) mutex_unlock(&mod_lock);
                return;
        }

        rcm_log_message(RCM_TRACE2, "unloading module %s\n", module->name);

        /*
         * Unlink the module from list
         */
        while (curr && (curr != module)) {
                prev = curr;
                curr = curr->next;
        }
        if (curr == NULL) {
                rcm_log_message(RCM_ERROR,
                    gettext("Unexpected error: module %s not found.\n"),
                    module->name);
        } else if (prev == NULL) {
                module_head = curr->next;
        } else {
                prev->next = curr->next;
        }
        (void) mutex_unlock(&mod_lock);

        module_unload(module);
}

/*
 * Gather usage info be passed back to requester. Discard info if user does
 * not care (list == NULL).
 */
void
add_busy_rsrc_to_list(char *alias, pid_t pid, int state, int seq_num,
    char *modname, const char *infostr, const char *errstr,
    nvlist_t *client_props, rcm_info_t **list)
{
        rcm_info_t *info;
        rcm_info_t *tmp;
        char *buf = NULL;
        size_t buflen = 0;

        if (list == NULL) {
                return;
        }

        info = s_calloc(1, sizeof (*info));
        if (errno = nvlist_alloc(&(info->info), NV_UNIQUE_NAME, 0)) {
                rcm_log_message(RCM_ERROR, "failed (nvlist_alloc=%s).\n",
                    strerror(errno));
                rcmd_exit(errno);
        }

        /*LINTED*/
        if ((errno = nvlist_add_string(info->info, RCM_RSRCNAME, alias)) ||
            (errno = nvlist_add_int32(info->info, RCM_SEQ_NUM, seq_num)) ||
            (errno = nvlist_add_int64(info->info, RCM_CLIENT_ID, pid)) ||
            (errno = nvlist_add_int32(info->info, RCM_RSRCSTATE, state))) {
                rcm_log_message(RCM_ERROR, "failed (nvlist_add=%s).\n",
                    strerror(errno));
                rcmd_exit(errno);
        }

        /*
         * Daemon calls to add_busy_rsrc_to_list may pass in
         * error/info. Add these through librcm interfaces.
         */
        if (errstr) {
                rcm_log_message(RCM_TRACE3, "adding error string: %s\n",
                    errstr);
                if (errno = nvlist_add_string(info->info, RCM_CLIENT_ERROR,
                    (char *)errstr)) {
                        rcm_log_message(RCM_ERROR, "failed (nvlist_add=%s).\n",
                            strerror(errno));
                        rcmd_exit(errno);
                }
        }

        if (infostr) {
                if (errno = nvlist_add_string(info->info, RCM_CLIENT_INFO,
                    (char *)infostr)) {
                        rcm_log_message(RCM_ERROR, "failed (nvlist_add=%s).\n",
                            strerror(errno));
                        rcmd_exit(errno);
                }
        }

        if (modname) {
                if (errno = nvlist_add_string(info->info, RCM_CLIENT_MODNAME,
                    modname)) {
                        rcm_log_message(RCM_ERROR, "failed (nvlist_add=%s).\n",
                            strerror(errno));
                        rcmd_exit(errno);
                }
        }

        if (client_props) {
                if (errno = nvlist_pack(client_props, &buf, &buflen,
                    NV_ENCODE_NATIVE, 0)) {
                        rcm_log_message(RCM_ERROR, "failed (nvlist_pack=%s).\n",
                            strerror(errno));
                        rcmd_exit(errno);
                }
                if (errno = nvlist_add_byte_array(info->info,
                    RCM_CLIENT_PROPERTIES, (uchar_t *)buf, buflen)) {
                        rcm_log_message(RCM_ERROR, "failed (nvlist_add=%s).\n",
                            strerror(errno));
                        rcmd_exit(errno);
                }
                (void) free(buf);
        }


        /* link info at end of list */
        if (*list) {
                tmp = *list;
                while (tmp->next)
                        tmp = tmp->next;
                tmp->next = info;
        } else {
                *list = info;
        }
}

/*
 * Resource client realted operations:
 *      rsrc_client_alloc, rsrc_client_find, rsrc_client_add,
 *      rsrc_client_remove, rsrc_client_action, rsrc_client_action_list
 */

/* Allocate rsrc_client_t structure. Load module if necessary. */
/*ARGSUSED*/
static client_t *
rsrc_client_alloc(char *alias, char *modname, pid_t pid, uint_t flag)
{
        client_t *client;
        module_t *mod;

        assert((alias != NULL) && (modname != NULL));

        rcm_log_message(RCM_TRACE4, "rsrc_client_alloc(%s, %s, %ld)\n",
            alias, modname, pid);

        if ((mod = cli_module_hold(modname)) == NULL) {
                return (NULL);
        }

        client = s_calloc(1, sizeof (client_t));
        client->module = mod;
        client->pid = pid;
        client->alias = s_strdup(alias);
        client->prv_flags = 0;
        client->state = RCM_STATE_ONLINE;
        client->flag = flag;

        /* This queue is protected by rcm_req_lock */
        rcm_enqueue_tail(&mod->client_q, &client->queue);

        return (client);
}

/* Find client in list matching modname and pid */
client_t *
rsrc_client_find(char *modname, pid_t pid, client_t **list)
{
        client_t *client = *list;

        rcm_log_message(RCM_TRACE4, "rsrc_client_find(%s, %ld, %p)\n",
            modname, pid, (void *)list);

        while (client) {
                if ((client->pid == pid) &&
                    strcmp(modname, client->module->name) == 0) {
                        break;
                }
                client = client->next;
        }
        return (client);
}

/* Add a client to client list */
static void
rsrc_client_add(client_t *client, client_t **list)
{
        rcm_log_message(RCM_TRACE4, "rsrc_client_add: %s, %s, %ld\n",
            client->alias, client->module->name, client->pid);

        client->next = *list;
        *list = client;
}

/* Remove client from list and destroy it */
static void
rsrc_client_remove(client_t *client, client_t **list)
{
        client_t *tmp, *prev = NULL;

        rcm_log_message(RCM_TRACE4, "rsrc_client_remove: %s, %s, %ld\n",
            client->alias, client->module->name, client->pid);

        tmp = *list;
        while (tmp) {
                if (client != tmp) {
                        prev = tmp;
                        tmp = tmp->next;
                        continue;
                }
                if (prev) {
                        prev->next = tmp->next;
                } else {
                        *list = tmp->next;
                }
                tmp->next = NULL;
                rsrc_clients_free(tmp);
                return;
        }
}

/* Free a list of clients. Called from cleanup thread only */
static void
rsrc_clients_free(client_t *list)
{
        client_t *client = list;

        while (client) {

                /*
                 * Note that the rcm daemon is single threaded while
                 * executing this routine. So there is no need to acquire
                 * rcm_req_lock here while dequeuing.
                 */
                rcm_dequeue(&client->queue);

                if (client->module) {
                        cli_module_rele(client->module);
                }
                list = client->next;
                if (client->alias) {
                        free(client->alias);
                }
                free(client);
                client = list;
        }
}

/*
 * Invoke a callback into a single client
 * This is the core of rcm_mod_ops interface
 */
static int
rsrc_client_action(client_t *client, int cmd, void *arg)
{
        int                     rval = RCM_SUCCESS;
        char                    *dummy_error = NULL;
        char                    *error = NULL;
        char                    *info = NULL;
        rcm_handle_t            *hdl;
        nvlist_t                *client_props = NULL;
        rcm_info_t              *depend_info = NULL;
        struct rcm_mod_ops      *ops = client->module->modops;
        tree_walk_arg_t         *targ = (tree_walk_arg_t *)arg;

        rcm_log_message(RCM_TRACE4,
            "rsrc_client_action: %s, %s, cmd=%d, flag=0x%x\n", client->alias,
            client->module->name, cmd, targ->flag);

        /*
         * Create a per-operation handle, increment seq_num by 1 so we will
         * know if a module uses this handle to callback into rcm_daemon.
         */
        hdl = rcm_handle_alloc(client->module);
        hdl->seq_num = targ->seq_num + 1;

        /*
         * Filter out operations for which the client didn't register.
         */
        switch (cmd) {
        case CMD_SUSPEND:
        case CMD_RESUME:
        case CMD_OFFLINE:
        case CMD_ONLINE:
        case CMD_REMOVE:
                if ((client->flag & RCM_REGISTER_DR) == 0) {
                        rcm_handle_free(hdl);
                        return (RCM_SUCCESS);
                }
                break;
        case CMD_REQUEST_CHANGE:
        case CMD_NOTIFY_CHANGE:
                if ((client->flag & RCM_REGISTER_CAPACITY) == 0) {
                        rcm_handle_free(hdl);
                        return (RCM_SUCCESS);
                }
                break;
        case CMD_EVENT:
                if ((client->flag & RCM_REGISTER_EVENT) == 0) {
                        rcm_handle_free(hdl);
                        return (RCM_SUCCESS);
                }
                break;
        }

        /*
         * Create nvlist_t for any client-specific properties.
         */
        if (errno = nvlist_alloc(&client_props, NV_UNIQUE_NAME, 0)) {
                rcm_log_message(RCM_ERROR,
                    "client action failed (nvlist_alloc=%s)\n",
                    strerror(errno));
                rcmd_exit(errno);
        }

        /*
         * Process the operation via a callback to the client module.
         */
        switch (cmd) {
        case CMD_GETINFO:
                rval = call_getinfo(ops, hdl, client->alias, client->pid,
                    targ->flag, &info, &error, client_props, &depend_info);
                break;

        case CMD_SUSPEND:
                if (((targ->flag & RCM_QUERY_CANCEL) == 0) &&
                    (client->state == RCM_STATE_SUSPEND)) {
                        break;
                }

                if ((targ->flag & RCM_QUERY) == 0) {
                        rcm_log_message(RCM_DEBUG, "suspending %s\n",
                            client->alias);
                } else if ((targ->flag & RCM_QUERY_CANCEL) == 0) {
                        rcm_log_message(RCM_DEBUG, "suspend query %s\n",
                            client->alias);
                } else {
                        rcm_log_message(RCM_DEBUG,
                            "suspend query %s cancelled\n", client->alias);
                }

                /*
                 * Update the client's state before the operation.
                 * If this is a cancelled query, then updating the state is
                 * the only thing that needs to be done, so break afterwards.
                 */
                if ((targ->flag & RCM_QUERY) == 0) {
                        client->state = RCM_STATE_SUSPENDING;
                } else if ((targ->flag & RCM_QUERY_CANCEL) == 0) {
                        client->state = RCM_STATE_SUSPEND_QUERYING;
                } else {
                        client->state = RCM_STATE_ONLINE;
                        break;
                }

                rval = ops->rcmop_request_suspend(hdl, client->alias,
                    client->pid, targ->interval, targ->flag, &error,
                    &depend_info);

                /* Update the client's state after the operation. */
                if ((targ->flag & RCM_QUERY) == 0) {
                        if (rval == RCM_SUCCESS) {
                                client->state = RCM_STATE_SUSPEND;
                        } else {
                                client->state = RCM_STATE_SUSPEND_FAIL;
                        }
                } else {
                        if (rval == RCM_SUCCESS) {
                                client->state = RCM_STATE_SUSPEND_QUERY;
                        } else {
                                client->state = RCM_STATE_SUSPEND_QUERY_FAIL;
                        }
                }
                break;

        case CMD_RESUME:
                if (client->state == RCM_STATE_ONLINE) {
                        break;
                }
                client->state = RCM_STATE_RESUMING;
                rval = ops->rcmop_notify_resume(hdl, client->alias, client->pid,
                    targ->flag, &error, &depend_info);

                /* online state is unconditional */
                client->state = RCM_STATE_ONLINE;
                break;

        case CMD_OFFLINE:
                if (((targ->flag & RCM_QUERY_CANCEL) == 0) &&
                    (client->state == RCM_STATE_OFFLINE)) {
                        break;
                }

                if ((targ->flag & RCM_QUERY) == 0) {
                        rcm_log_message(RCM_DEBUG, "offlining %s\n",
                            client->alias);
                } else if ((targ->flag & RCM_QUERY_CANCEL) == 0) {
                        rcm_log_message(RCM_DEBUG, "offline query %s\n",
                            client->alias);
                } else {
                        rcm_log_message(RCM_DEBUG,
                            "offline query %s cancelled\n", client->alias);
                }

                /*
                 * Update the client's state before the operation.
                 * If this is a cancelled query, then updating the state is
                 * the only thing that needs to be done, so break afterwards.
                 */
                if ((targ->flag & RCM_QUERY) == 0) {
                        client->state = RCM_STATE_OFFLINING;
                } else if ((targ->flag & RCM_QUERY_CANCEL) == 0) {
                        client->state = RCM_STATE_OFFLINE_QUERYING;
                } else {
                        client->state = RCM_STATE_ONLINE;
                        break;
                }

                rval = ops->rcmop_request_offline(hdl, client->alias,
                    client->pid, targ->flag, &error, &depend_info);

                /*
                 * If this is a retire operation and we managed to call
                 * into at least one client, set retcode to RCM_SUCCESS to
                 * indicate that retire has been subject to constraints
                 * This retcode will be further modified by actual return
                 * code.
                 */
                if ((targ->flag & RCM_RETIRE_REQUEST) &&
                    (targ->retcode == RCM_NO_CONSTRAINT)) {
                        rcm_log_message(RCM_DEBUG,
                            "at least 1 client, constraint applied: %s\n",
                            client->alias);
                        targ->retcode = RCM_SUCCESS;
                }

                /* Update the client's state after the operation. */
                if ((targ->flag & RCM_QUERY) == 0) {
                        if (rval == RCM_SUCCESS) {
                                client->state = RCM_STATE_OFFLINE;
                        } else {
                                client->state = RCM_STATE_OFFLINE_FAIL;
                        }
                } else {
                        if (rval == RCM_SUCCESS) {
                                client->state = RCM_STATE_OFFLINE_QUERY;
                        } else {
                                client->state = RCM_STATE_OFFLINE_QUERY_FAIL;
                        }
                }
                break;

        case CMD_ONLINE:
                if (client->state == RCM_STATE_ONLINE) {
                        break;
                }

                rcm_log_message(RCM_DEBUG, "onlining %s\n", client->alias);

                client->state = RCM_STATE_ONLINING;
                rval = ops->rcmop_notify_online(hdl, client->alias, client->pid,
                    targ->flag, &error, &depend_info);
                client->state = RCM_STATE_ONLINE;
                break;

        case CMD_REMOVE:
                rcm_log_message(RCM_DEBUG, "removing %s\n", client->alias);
                client->state = RCM_STATE_REMOVING;
                rval = ops->rcmop_notify_remove(hdl, client->alias, client->pid,
                    targ->flag, &error, &depend_info);
                client->state = RCM_STATE_REMOVE;
                break;

        case CMD_REQUEST_CHANGE:
                rcm_log_message(RCM_DEBUG, "requesting state change of %s\n",
                    client->alias);
                if (ops->rcmop_request_capacity_change)
                        rval = ops->rcmop_request_capacity_change(hdl,
                            client->alias, client->pid, targ->flag, targ->nvl,
                            &error, &depend_info);
                break;

        case CMD_NOTIFY_CHANGE:
                rcm_log_message(RCM_DEBUG, "requesting state change of %s\n",
                    client->alias);
                if (ops->rcmop_notify_capacity_change)
                        rval = ops->rcmop_notify_capacity_change(hdl,
                            client->alias, client->pid, targ->flag, targ->nvl,
                            &error, &depend_info);
                break;

        case CMD_EVENT:
                rcm_log_message(RCM_DEBUG, "delivering event to %s\n",
                    client->alias);
                if (ops->rcmop_notify_event)
                        rval = ops->rcmop_notify_event(hdl, client->alias,
                            client->pid, targ->flag, &error, targ->nvl,
                            &depend_info);
                break;

        default:
                rcm_log_message(RCM_ERROR, gettext("unknown command %d\n"),
                    cmd);
                rval = RCM_FAILURE;
                break;
        }

        /* reset error code to the most significant error */
        if (rval != RCM_SUCCESS)
                targ->retcode = rval;

        /*
         * XXX - The code below may produce duplicate rcm_info_t's on error?
         */
        if ((cmd != CMD_GETINFO) &&
            ((rval != RCM_SUCCESS) ||
            (error != NULL) ||
            (targ->flag & RCM_SCOPE))) {
                (void) call_getinfo(ops, hdl, client->alias, client->pid,
                    targ->flag & (~(RCM_INCLUDE_DEPENDENT|RCM_INCLUDE_SUBTREE)),
                    &info, &dummy_error, client_props, &depend_info);
                if (dummy_error)
                        (void) free(dummy_error);
        } else if (cmd != CMD_GETINFO) {
                nvlist_free(client_props);
                client_props = NULL;
        }

        if (client_props) {
                add_busy_rsrc_to_list(client->alias, client->pid, client->state,
                    targ->seq_num, client->module->name, info, error,
                    client_props, targ->info);
                nvlist_free(client_props);
        }

        if (info)
                (void) free(info);
        if (error)
                (void) free(error);

        if (depend_info) {
                if (targ->info) {
                        (void) rcm_append_info(targ->info, depend_info);
                } else {
                        rcm_free_info(depend_info);
                }
        }

        rcm_handle_free(hdl);
        return (rval);
}

/*
 * invoke a callback into a list of clients, return 0 if all success
 */
int
rsrc_client_action_list(client_t *list, int cmd, void *arg)
{
        int error, rval = RCM_SUCCESS;
        tree_walk_arg_t         *targ = (tree_walk_arg_t *)arg;

        while (list) {
                client_t *client = list;
                list = client->next;

                /*
                 * Make offline idempotent in the retire
                 * case
                 */
                if ((targ->flag & RCM_RETIRE_REQUEST) &&
                    client->state == RCM_STATE_REMOVE) {
                        client->state = RCM_STATE_ONLINE;
                        rcm_log_message(RCM_DEBUG, "RETIRE: idempotent client "
                            "state: REMOVE -> ONLINE: %s\n", client->alias);
                }

                if (client->state == RCM_STATE_REMOVE)
                        continue;

                error = rsrc_client_action(client, cmd, arg);
                if (error != RCM_SUCCESS) {
                        rval = error;
                }
        }

        return (rval);
}

/*
 * Node realted operations:
 *
 *      rn_alloc, rn_free, rn_find_child,
 *      rn_get_child, rn_get_sibling,
 *      rsrc_node_find, rsrc_node_add_user, rsrc_node_remove_user,
 */

/* Allocate node based on a logical or physical name */
static rsrc_node_t *
rn_alloc(char *name, int type)
{
        rsrc_node_t *node;

        rcm_log_message(RCM_TRACE4, "rn_alloc(%s, %d)\n", name, type);

        node = s_calloc(1, sizeof (*node));
        node->name = s_strdup(name);
        node->type = type;

        return (node);
}

/*
 * Free node along with its siblings and children
 */
static void
rn_free(rsrc_node_t *node)
{
        if (node == NULL) {
                return;
        }

        if (node->child) {
                rn_free(node->child);
        }

        if (node->sibling) {
                rn_free(node->sibling);
        }

        rsrc_clients_free(node->users);
        free(node->name);
        free(node);
}

/*
 * Find next sibling
 */
static rsrc_node_t *
rn_get_sibling(rsrc_node_t *node)
{
        return (node->sibling);
}

/*
 * Find first child
 */
static rsrc_node_t *
rn_get_child(rsrc_node_t *node)
{
        return (node->child);
}

/*
 * Find child named childname. Create it if flag is RSRC_NODE_CRTEATE
 */
static rsrc_node_t *
rn_find_child(rsrc_node_t *parent, char *childname, int flag, int type)
{
        rsrc_node_t *child = parent->child;
        rsrc_node_t *new, *prev = NULL;

        rcm_log_message(RCM_TRACE4,
            "rn_find_child(parent=%s, child=%s, 0x%x, %d)\n",
            parent->name, childname, flag, type);

        /*
         * Children are ordered based on strcmp.
         */
        while (child && (strcmp(child->name, childname) < 0)) {
                prev = child;
                child = child->sibling;
        }

        if (child && (strcmp(child->name, childname) == 0)) {
                return (child);
        }

        if (flag != RSRC_NODE_CREATE)
                return (NULL);

        new = rn_alloc(childname, type);
        new->parent = parent;
        new->sibling = child;

        /*
         * Set this linkage last so we don't break ongoing operations.
         *
         * N.B. Assume setting a pointer is an atomic operation.
         */
        if (prev == NULL) {
                parent->child = new;
        } else {
                prev->sibling = new;
        }

        return (new);
}

/*
 * Pathname related help functions
 */
static void
pn_preprocess(char *pathname, int type)
{
        char *tmp;

        if (type != RSRC_TYPE_DEVICE)
                return;

        /*
         * For devices, convert ':' to '/' (treat minor nodes and children)
         */
        tmp = strchr(pathname, ':');
        if (tmp == NULL)
                return;

        *tmp = '/';
}

static char *
pn_getnextcomp(char *pathname, char **lasts)
{
        char *slash;

        if (pathname == NULL)
                return (NULL);

        /* skip slashes' */
        while (*pathname == '/')
                ++pathname;

        if (*pathname == '\0')
                return (NULL);

        slash = strchr(pathname, '/');
        if (slash != NULL) {
                *slash = '\0';
                *lasts = slash + 1;
        } else {
                *lasts = NULL;
        }

        return (pathname);
}

/*
 * Find a node in tree based on device, which is the physical pathname
 * of the form /sbus@.../esp@.../sd@...
 */
int
rsrc_node_find(char *rsrcname, int flag, rsrc_node_t **nodep)
{
        char *pathname, *nodename, *lasts;
        rsrc_node_t *node;
        int type;

        rcm_log_message(RCM_TRACE4, "rn_node_find(%s, 0x%x)\n", rsrcname, flag);

        /*
         * For RSRC_TYPE_ABSTRACT, look under /ABSTRACT. For other types,
         * look under /SYSTEM.
         */
        pathname = resolve_name(rsrcname);
        if (pathname == NULL)
                return (EINVAL);

        type = rsrc_get_type(pathname);
        switch (type) {
        case RSRC_TYPE_DEVICE:
        case RSRC_TYPE_NORMAL:
                node = rn_find_child(rsrc_root, "SYSTEM", RSRC_NODE_CREATE,
                    RSRC_TYPE_NORMAL);
                break;

        case RSRC_TYPE_ABSTRACT:
                node = rn_find_child(rsrc_root, "ABSTRACT", RSRC_NODE_CREATE,
                    RSRC_TYPE_NORMAL);
                break;

        default:
                /* just to make sure */
                free(pathname);
                return (EINVAL);
        }

        /*
         * Find position of device within tree. Upon exiting the loop, device
         * should be placed between prev and curr.
         */
        pn_preprocess(pathname, type);
        lasts = pathname;
        while ((nodename = pn_getnextcomp(lasts, &lasts)) != NULL) {
                rsrc_node_t *parent = node;
                node = rn_find_child(parent, nodename, flag, type);
                if (node == NULL) {
                        assert((flag & RSRC_NODE_CREATE) == 0);
                        free(pathname);
                        *nodep = NULL;
                        return (RCM_SUCCESS);
                }
        }
        free(pathname);
        *nodep = node;
        return (RCM_SUCCESS);
}

/*
 * add a usage client to a node
 */
/*ARGSUSED*/
int
rsrc_node_add_user(rsrc_node_t *node, char *alias, char *modname, pid_t pid,
    uint_t flag)
{
        client_t *user;

        rcm_log_message(RCM_TRACE3,
            "rsrc_node_add_user(%s, %s, %s, %ld, 0x%x)\n",
            node->name, alias, modname, pid, flag);

        user = rsrc_client_find(modname, pid, &node->users);

        /*
         * If a client_t already exists, add the registration and return
         * success if it's a valid registration request.
         *
         * Return EALREADY if the resource is already registered.
         * This means either the client_t already has the requested
         * registration flagged, or that a DR registration was attempted
         * on a resource already in use in the DR operations state model.
         */
        if (user != NULL) {

                if (user->flag & (flag & RCM_REGISTER_MASK)) {
                        return (EALREADY);
                }

                if ((flag & RCM_REGISTER_DR) &&
                    (user->state != RCM_STATE_REMOVE)) {
                        return (EALREADY);
                }

                user->flag |= (flag & RCM_REGISTER_MASK);
                if ((flag & RCM_REGISTER_DR) ||
                    (user->state == RCM_STATE_REMOVE)) {
                        user->state = RCM_STATE_ONLINE;
                }

                return (RCM_SUCCESS);
        }

        /*
         * Otherwise create a new client_t and create a new registration.
         */
        if ((user = rsrc_client_alloc(alias, modname, pid, flag)) != NULL) {
                rsrc_client_add(user, &node->users);
        }
        if (flag & RCM_FILESYS)
                node->type = RSRC_TYPE_FILESYS;

        return (RCM_SUCCESS);
}

/*
 * remove a usage client of a node
 */
int
rsrc_node_remove_user(rsrc_node_t *node, char *modname, pid_t pid, uint_t flag)
{
        client_t *user;

        rcm_log_message(RCM_TRACE3,
            "rsrc_node_remove_user(%s, %s, %ld, 0x%x)\n", node->name, modname,
            pid, flag);

        user = rsrc_client_find(modname, pid, &node->users);
        if ((user == NULL) || (user->state == RCM_STATE_REMOVE)) {
                rcm_log_message(RCM_NOTICE, gettext(
                    "client not registered: module=%s, pid=%d, dev=%s\n"),
                    modname, pid, node->name);
                return (ENOENT);
        }

        /* Strip off the registration being removed (DR, event, capacity) */
        user->flag = user->flag & (~(flag & RCM_REGISTER_MASK));

        /*
         * Mark the client as removed if all registrations have been removed
         */
        if ((user->flag & RCM_REGISTER_MASK) == 0)
                user->state = RCM_STATE_REMOVE;

        return (RCM_SUCCESS);
}

/*
 * Tree walking function - rsrc_walk
 */

#define MAX_TREE_DEPTH          32

#define RN_WALK_CONTINUE        0
#define RN_WALK_PRUNESIB        1
#define RN_WALK_PRUNECHILD      2
#define RN_WALK_TERMINATE       3

#define EMPTY_STACK(sp)         ((sp)->depth == 0)
#define TOP_NODE(sp)            ((sp)->node[(sp)->depth - 1])
#define PRUNE_SIB(sp)           ((sp)->prunesib[(sp)->depth - 1])
#define PRUNE_CHILD(sp)         ((sp)->prunechild[(sp)->depth - 1])
#define POP_STACK(sp)           ((sp)->depth)--
#define PUSH_STACK(sp, rn)      \
        (sp)->node[(sp)->depth] = (rn); \
        (sp)->prunesib[(sp)->depth] = 0;        \
        (sp)->prunechild[(sp)->depth] = 0;      \
        ((sp)->depth)++

struct rn_stack {
        rsrc_node_t *node[MAX_TREE_DEPTH];
        char    prunesib[MAX_TREE_DEPTH];
        char    prunechild[MAX_TREE_DEPTH];
        int     depth;
};

/* walking one node and update node stack */
/*ARGSUSED*/
static void
walk_one_node(struct rn_stack *sp, void *arg,
    int (*node_callback)(rsrc_node_t *, void *))
{
        int prunesib;
        rsrc_node_t *child, *sibling;
        rsrc_node_t *node = TOP_NODE(sp);

        rcm_log_message(RCM_TRACE4, "walk_one_node(%s)\n", node->name);

        switch (node_callback(node, arg)) {
        case RN_WALK_TERMINATE:
                POP_STACK(sp);
                while (!EMPTY_STACK(sp)) {
                        node = TOP_NODE(sp);
                        POP_STACK(sp);
                }
                return;

        case RN_WALK_PRUNESIB:
                PRUNE_SIB(sp) = 1;
                break;

        case RN_WALK_PRUNECHILD:
                PRUNE_CHILD(sp) = 1;
                break;

        case RN_WALK_CONTINUE:
        default:
                break;
        }

        /*
         * Push child on the stack
         */
        if (!PRUNE_CHILD(sp) && (child = rn_get_child(node)) != NULL) {
                PUSH_STACK(sp, child);
                return;
        }

        /*
         * Pop the stack till a node's sibling can be pushed
         */
        prunesib = PRUNE_SIB(sp);
        POP_STACK(sp);
        while (!EMPTY_STACK(sp) &&
            (prunesib || (sibling = rn_get_sibling(node)) == NULL)) {
                node = TOP_NODE(sp);
                prunesib = PRUNE_SIB(sp);
                POP_STACK(sp);
        }

        if (EMPTY_STACK(sp)) {
                return;
        }

        /*
         * push sibling onto the stack
         */
        PUSH_STACK(sp, sibling);
}

/*
 * walk tree rooted at root in child-first order
 */
static void
rsrc_walk(rsrc_node_t *root, void *arg,
    int (*node_callback)(rsrc_node_t *, void *))
{
        struct rn_stack stack;

        rcm_log_message(RCM_TRACE3, "rsrc_walk(%s)\n", root->name);

        /*
         * Push root on stack and walk in child-first order
         */
        stack.depth = 0;
        PUSH_STACK(&stack, root);
        PRUNE_SIB(&stack) = 1;

        while (!EMPTY_STACK(&stack)) {
                walk_one_node(&stack, arg, node_callback);
        }
}

/*
 * Callback for a command action on a node
 */
static int
node_action(rsrc_node_t *node, void *arg)
{
        tree_walk_arg_t *targ = (tree_walk_arg_t *)arg;
        uint_t flag = targ->flag;

        rcm_log_message(RCM_TRACE4, "node_action(%s)\n", node->name);

        /*
         * If flag indicates operation on a filesystem, we don't callback on
         * the filesystem root to avoid infinite recursion on filesystem module.
         *
         * N.B. Such request should only come from filesystem RCM module.
         */
        if (flag & RCM_FILESYS) {
                assert(node->type == RSRC_TYPE_FILESYS);
                targ->flag &= ~RCM_FILESYS;
                return (RN_WALK_CONTINUE);
        }

        /*
         * Execute state change callback
         */
        (void) rsrc_client_action_list(node->users, targ->cmd, arg);

        /*
         * Upon hitting a filesys root, prune children.
         * The filesys module should have taken care of
         * children by now.
         */
        if (node->type == RSRC_TYPE_FILESYS)
                return (RN_WALK_PRUNECHILD);

        return (RN_WALK_CONTINUE);
}

/*
 * Execute a command on a subtree under root.
 */
int
rsrc_tree_action(rsrc_node_t *root, int cmd, tree_walk_arg_t *arg)
{
        rcm_log_message(RCM_TRACE2, "tree_action(%s, %d)\n", root->name, cmd);

        arg->cmd = cmd;

        /*
         * If RCM_RETIRE_REQUEST is set, just walk one node and preset
         * retcode to NO_CONSTRAINT
         */
        if (arg->flag & RCM_RETIRE_REQUEST) {
                rcm_log_message(RCM_TRACE1, "tree_action: RETIRE_REQ: walking "
                    "only root node: %s\n", root->name);
                arg->retcode = RCM_NO_CONSTRAINT;
                (void) node_action(root, arg);
        } else {
                arg->retcode = RCM_SUCCESS;
                rsrc_walk(root, (void *)arg, node_action);
        }

        return (arg->retcode);
}

/*
 * Get info on current regsitrations
 */
int
rsrc_usage_info(char **rsrcnames, uint_t flag, int seq_num, rcm_info_t **info)
{
        rsrc_node_t *node;
        rcm_info_t *result = NULL;
        tree_walk_arg_t arg;
        int initial_req;
        int rv;
        int i;

        arg.flag = flag;
        arg.info = &result;
        arg.seq_num = seq_num;

        for (i = 0; rsrcnames[i] != NULL; i++) {

                rcm_log_message(RCM_TRACE2, "rsrc_usage_info(%s, 0x%x, %d)\n",
                    rsrcnames[i], flag, seq_num);

                if (flag & RCM_INCLUDE_DEPENDENT) {
                        initial_req = ((seq_num & SEQ_NUM_MASK) == 0);

                        /*
                         * if redundant request, skip the operation
                         */
                        if (info_req_add(rsrcnames[i], flag, seq_num) != 0) {
                                continue;
                        }
                }

                rv = rsrc_node_find(rsrcnames[i], 0, &node);
                if ((rv != RCM_SUCCESS) || (node == NULL)) {
                        if ((flag & RCM_INCLUDE_DEPENDENT) && initial_req)
                                info_req_remove(seq_num);
                        continue;
                }

                /*
                 * Based on RCM_INCLUDE_SUBTREE flag, query either the subtree
                 * or just the node.
                 */
                if (flag & RCM_INCLUDE_SUBTREE) {
                        (void) rsrc_tree_action(node, CMD_GETINFO, &arg);
                } else {
                        arg.cmd = CMD_GETINFO;
                        (void) node_action(node, (void *)&arg);
                }

                if ((flag & RCM_INCLUDE_DEPENDENT) && initial_req)
                        info_req_remove(seq_num);
        }

        (void) rcm_append_info(info, result);
        return (rv);
}

/*
 * Get the list of currently loaded module
 */
rcm_info_t *
rsrc_mod_info()
{
        module_t *mod;
        rcm_info_t *info = NULL;

        (void) mutex_lock(&mod_lock);
        mod = module_head;
        while (mod) {
                char *modinfo = s_strdup(module_info(mod));
                add_busy_rsrc_to_list("dummy", 0, 0, 0, mod->name,
                    modinfo, NULL, NULL, &info);
                mod = mod->next;
        }
        (void) mutex_unlock(&mod_lock);

        return (info);
}

/*
 * Initialize resource map - load all modules
 */
void
rcmd_db_init()
{
        char *tmp;
        DIR *mod_dir;
        struct dirent *entp;
        int i;
        char *dir_name;
        int rcm_script;

        rcm_log_message(RCM_DEBUG, "rcmd_db_init(): initialize database\n");

        if (script_main_init() == -1)
                rcmd_exit(errno);

        rsrc_root = rn_alloc("/", RSRC_TYPE_NORMAL);

        for (i = 0; (dir_name = rcm_dir(i, &rcm_script)) != NULL; i++) {

                if ((mod_dir = opendir(dir_name)) == NULL) {
                        continue;       /* try next directory */
                }

                rcm_log_message(RCM_TRACE2, "search directory %s\n", dir_name);

                while ((entp = readdir(mod_dir)) != NULL) {
                        module_t *module;

                        if (strcmp(entp->d_name, ".") == 0 ||
                            strcmp(entp->d_name, "..") == 0)
                                continue;

                        if (rcm_script == 0) {
                                /* rcm module */
                                if (((tmp = strstr(entp->d_name,
                                    RCM_MODULE_SUFFIX)) == NULL) ||
                                    (tmp[strlen(RCM_MODULE_SUFFIX)] != '\0')) {
                                        continue;
                                }
                        }

                        module = cli_module_hold(entp->d_name);
                        if (module == NULL) {
                                if (rcm_script == 0)
                                        rcm_log_message(RCM_ERROR,
                                            gettext("%s: failed to load\n"),
                                            entp->d_name);
                                continue;
                        }

                        if (module->ref_count == MOD_REFCNT_INIT) {
                                /*
                                 * ask module to register for resource 1st time
                                 */
                                module_attach(module);
                        }
                        cli_module_rele(module);
                }
                (void) closedir(mod_dir);
        }

        rcmd_db_print();
}

/*
 * sync resource map - ask all modules to register again
 */
void
rcmd_db_sync()
{
        static time_t sync_time = (time_t)-1;
        const time_t interval = 5;      /* resync at most every 5 sec */

        module_t *mod;
        time_t curr = time(NULL);

        if ((sync_time != (time_t)-1) && (curr - sync_time < interval))
                return;

        sync_time = curr;
        (void) mutex_lock(&mod_lock);
        mod = module_head;
        while (mod) {
                /*
                 * Hold module by incrementing ref count and release
                 * mod_lock to avoid deadlock, since rcmop_register()
                 * may callback into the daemon and request mod_lock.
                 */
                mod->ref_count++;
                (void) mutex_unlock(&mod_lock);

                mod->modops->rcmop_register(mod->rcmhandle);

                (void) mutex_lock(&mod_lock);
                mod->ref_count--;
                mod = mod->next;
        }
        (void) mutex_unlock(&mod_lock);
}

/*
 * Determine if a process is alive
 */
int
proc_exist(pid_t pid)
{
        char path[64];
        const char *procfs = "/proc";
        struct stat sb;

        if (pid == (pid_t)0) {
                return (1);
        }

        (void) snprintf(path, sizeof (path), "%s/%ld", procfs, pid);
        return (stat(path, &sb) == 0);
}

/*
 * Cleaup client list
 *
 * N.B. This routine runs in a single-threaded environment only. It is only
 *      called by the cleanup thread, which never runs in parallel with other
 *      threads.
 */
static void
clean_client_list(client_t **listp)
{
        client_t *client = *listp;

        /*
         * Cleanup notification clients for which pid no longer exists
         */
        while (client) {
                if ((client->state != RCM_STATE_REMOVE) &&
                    proc_exist(client->pid)) {
                        listp = &client->next;
                        client = *listp;
                        continue;
                }

                /*
                 * Destroy this client_t. rsrc_client_remove updates
                 * listp to point to the next client.
                 */
                rsrc_client_remove(client, listp);
                client = *listp;
        }
}

/*ARGSUSED*/
static int
clean_node(rsrc_node_t *node, void *arg)
{
        rcm_log_message(RCM_TRACE4, "clean_node(%s)\n", node->name);

        clean_client_list(&node->users);

        return (RN_WALK_CONTINUE);
}

static void
clean_rsrc_tree()
{
        rcm_log_message(RCM_TRACE4,
            "clean_rsrc_tree(): delete stale dr clients\n");

        rsrc_walk(rsrc_root, NULL, clean_node);
}

static void *
db_clean(void *arg __unused)
{
        extern barrier_t barrier;
        extern void clean_dr_list();

        for (;;) {
                (void) mutex_lock(&rcm_req_lock);
                start_polling_thread();
                (void) mutex_unlock(&rcm_req_lock);

                (void) mutex_lock(&barrier.lock);
                while (need_cleanup == 0)
                        (void) cond_wait(&barrier.cv, &barrier.lock);
                (void) mutex_unlock(&barrier.lock);

                /*
                 * Make sure all other threads are either blocked or exited.
                 */
                rcmd_set_state(RCMD_CLEANUP);

                need_cleanup = 0;

                /*
                 * clean dr_req_list
                 */
                clean_dr_list();

                /*
                 * clean resource tree
                 */
                clean_rsrc_tree();

                rcmd_set_state(RCMD_NORMAL);
        }
        return (NULL);
}

void
rcmd_db_clean(void)
{
        rcm_log_message(RCM_DEBUG,
            "rcm_db_clean(): launch thread to clean database\n");

        if (thr_create(NULL, 0, db_clean, NULL, THR_DETACHED, NULL) != 0) {
                rcm_log_message(RCM_WARNING,
                    gettext("failed to create cleanup thread %s\n"),
                    strerror(errno));
        }
}

/*ARGSUSED*/
static int
print_node(rsrc_node_t *node, void *arg)
{
        client_t *user;

        rcm_log_message(RCM_DEBUG, "rscname: %s, state = 0x%x\n", node->name);
        rcm_log_message(RCM_DEBUG, "    users:\n");

        if ((user = node->users) == NULL) {
                rcm_log_message(RCM_DEBUG, "    none\n");
                return (RN_WALK_CONTINUE);
        }

        while (user) {
                rcm_log_message(RCM_DEBUG, "    %s, %d, %s\n",
                    user->module->name, user->pid, user->alias);
                user = user->next;
        }
        return (RN_WALK_CONTINUE);
}

static void
rcmd_db_print()
{
        module_t *mod;

        rcm_log_message(RCM_DEBUG, "modules:\n");
        (void) mutex_lock(&mod_lock);
        mod = module_head;
        while (mod) {
                rcm_log_message(RCM_DEBUG, "    %s\n", mod->name);
                mod = mod->next;
        }
        (void) mutex_unlock(&mod_lock);

        rcm_log_message(RCM_DEBUG, "\nresource tree:\n");

        rsrc_walk(rsrc_root, NULL, print_node);

        rcm_log_message(RCM_DEBUG, "\n");
}

/*
 * Allocate handle from calling into each RCM module
 */
static rcm_handle_t *
rcm_handle_alloc(module_t *module)
{
        rcm_handle_t *hdl;

        hdl = s_malloc(sizeof (rcm_handle_t));

        hdl->modname = module->name;
        hdl->pid = 0;
        hdl->lrcm_ops = &rcm_ops;       /* for callback into daemon directly */
        hdl->module = module;

        return (hdl);
}

/*
 * Free rcm_handle_t
 */
static void
rcm_handle_free(rcm_handle_t *handle)
{
        free(handle);
}

/*
 * help function that exit on memory outage
 */
void *
s_malloc(size_t size)
{
        void *buf = malloc(size);

        if (buf == NULL) {
                rcmd_exit(ENOMEM);
        }
        return (buf);
}

void *
s_calloc(int n, size_t size)
{
        void *buf = calloc(n, size);

        if (buf == NULL) {
                rcmd_exit(ENOMEM);
        }
        return (buf);
}

void *
s_realloc(void *ptr, size_t size)
{
        void *new = realloc(ptr, size);

        if (new == NULL) {
                rcmd_exit(ENOMEM);
        }
        return (new);
}

char *
s_strdup(const char *str)
{
        char *buf = strdup(str);

        if (buf == NULL) {
                rcmd_exit(ENOMEM);
        }
        return (buf);
}

/*
 * Convert a version 1 ops vector to current ops vector
 * Fields missing in version 1 are set to NULL.
 */
static struct rcm_mod_ops *
modops_from_v1(void *ops_v1)
{
        struct rcm_mod_ops *ops;

        ops = s_calloc(1, sizeof (struct rcm_mod_ops));
        bcopy(ops_v1, ops, sizeof (struct rcm_mod_ops_v1));
        return (ops);
}

/* call a module's getinfo routine; detects v1 ops and adjusts the call */
static int
call_getinfo(struct rcm_mod_ops *ops, rcm_handle_t *hdl, char *alias, id_t pid,
    uint_t flag, char **info, char **error, nvlist_t *client_props,
    rcm_info_t **infop)
{
        int rval;
        struct rcm_mod_ops_v1 *v1_ops;

        if (ops->version == RCM_MOD_OPS_V1) {
                v1_ops = (struct rcm_mod_ops_v1 *)ops;
                rval = v1_ops->rcmop_get_info(hdl, alias, pid, flag, info,
                    infop);
                if (rval != RCM_SUCCESS && *info != NULL)
                        *error = strdup(*info);
                return (rval);
        } else {
                return (ops->rcmop_get_info(hdl, alias, pid, flag, info, error,
                    client_props, infop));
        }
}

void
rcm_init_queue(rcm_queue_t *head)
{
        head->next = head->prev = head;
}

void
rcm_enqueue_head(rcm_queue_t *head, rcm_queue_t *element)
{
        rcm_enqueue(head, element);
}

void
rcm_enqueue_tail(rcm_queue_t *head, rcm_queue_t *element)
{
        rcm_enqueue(head->prev, element);
}

void
rcm_enqueue(rcm_queue_t *list_element, rcm_queue_t *element)
{
        element->next = list_element->next;
        element->prev = list_element;
        element->next->prev = element;
        list_element->next = element;
}

rcm_queue_t *
rcm_dequeue_head(rcm_queue_t *head)
{
        rcm_queue_t     *element = head->next;
        rcm_dequeue(element);
        return (element);
}

rcm_queue_t *
rcm_dequeue_tail(rcm_queue_t *head)
{
        rcm_queue_t     *element = head->prev;
        rcm_dequeue(element);
        return (element);
}

void
rcm_dequeue(rcm_queue_t *element)
{
        element->prev->next = element->next;
        element->next->prev = element->prev;
        element->next = element->prev = NULL;
}