libhotplug/common/libhotplug.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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <door.h>
#include <libnvpair.h>
#include <libhotplug.h>
#include <libhotplug_impl.h>
#include <sys/sunddi.h>
#include <sys/ddi_hp.h>

static void i_hp_dprintf(const char *fmt, ...);
static int  i_hp_pack_branch(hp_node_t, char **, size_t *);
static int  i_hp_pack_node(hp_node_t, char **, size_t *);
static int  i_hp_unpack_node(char *, size_t, hp_node_t, hp_node_t *);
static int  i_hp_unpack_branch(char *, size_t, hp_node_t, hp_node_t *);
static int  i_hp_call_hotplugd(nvlist_t *, nvlist_t **);
static nvlist_t *i_hp_set_args(hp_cmd_t, const char *, const char *, uint_t,
            const char *, int);
static int  i_hp_parse_results(nvlist_t *, hp_node_t *, char **);

/*
 * Global flag to enable debug features.
 */
int libhotplug_debug = 0;

/*
 * hp_init()
 *
 *  Initialize a hotplug information snapshot.
 */
hp_node_t
hp_init(const char *path, const char *connection, uint_t flags)
{
    nvlist_t    *args;
    nvlist_t    *results;
    hp_node_t   root = NULL;
    int     rv;

    i_hp_dprintf("hp_init: path=%p, connection=%p, flags=0x%x\n",
        (void *)path, (void *)connection, flags);

    /* Check arguments */
    if ((path == NULL) || !HP_INIT_FLAGS_VALID(flags)) {
        i_hp_dprintf("hp_init: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    /* Build arguments for door call */
    if ((args = i_hp_set_args(HP_CMD_GETINFO, path, connection, flags,
        NULL, 0)) == NULL) {
        i_hp_dprintf("hp_init: cannot build arguments nvlist.\n");
        errno = ENOMEM;
        return (NULL);
    }

    /* Make the door call to hotplugd */
    rv = i_hp_call_hotplugd(args, &results);

    /* Arguments no longer needed */
    nvlist_free(args);

    /* Parse additional results, if any */
    if ((rv == 0) && (results != NULL)) {
        rv = i_hp_parse_results(results, &root, NULL);
        nvlist_free(results);
    }

    /* Check for errors */
    if (rv != 0) {
        i_hp_dprintf("hp_init: failure (%s).\n", strerror(rv));
        if (root)
            hp_fini(root);
        errno = rv;
        return (NULL);
    }

    /* Success requires an info snapshot */
    if (root == NULL) {
        i_hp_dprintf("hp_init: missing info snapshot.\n");
        errno = EFAULT;
        return (NULL);
    }

    /* Success */
    return (root);
}

/*
 * hp_fini()
 *
 *  Terminate and clean-up a hotplug information snapshot.
 */
void
hp_fini(hp_node_t root)
{
    hp_node_t   node;
    hp_node_t   sibling;
    char        *basepath;

    i_hp_dprintf("hp_fini: root=%p\n", (void *)root);

    if (root == NULL) {
        i_hp_dprintf("hp_fini: invalid arguments.\n");
        return;
    }

    /* Extract and free base path */
    if (root->hp_basepath) {
        basepath = root->hp_basepath;
        for (node = root; node != NULL; node = node->hp_sibling)
            node->hp_basepath = NULL;
        free(basepath);
    }

    /* Destroy the nodes */
    node = root;
    while (node) {
        sibling = node->hp_sibling;
        if (node->hp_child)
            hp_fini(node->hp_child);
        if (node->hp_name)
            free(node->hp_name);
        if (node->hp_usage)
            free(node->hp_usage);
        if (node->hp_description)
            free(node->hp_description);
        free(node);
        node = sibling;
    }
}

/*
 * hp_traverse()
 *
 *  Walk a graph of hotplug nodes, executing a callback on each node.
 */
int
hp_traverse(hp_node_t root, void *arg, int (*hp_callback)(hp_node_t, void *arg))
{
    int     rv;
    hp_node_t   node;

    i_hp_dprintf("hp_traverse: root=%p, arg=%p, hp_callback=%p\n",
        (void *)root, arg, (void *)hp_callback);

    /* Check arguments */
    if ((root == NULL) || (hp_callback == NULL)) {
        i_hp_dprintf("hp_traverse: invalid arguments.\n");
        errno = EINVAL;
        return (-1);
    }

    for (node = root; node; node = node->hp_sibling) {
        rv = hp_callback(node, arg);

        if (rv == HP_WALK_TERMINATE) {
            i_hp_dprintf("hp_traverse: walk terminated.\n");
            return (HP_WALK_TERMINATE);
        }

        if (node->hp_child && (rv != HP_WALK_PRUNECHILD))
            if (hp_traverse(node->hp_child, arg, hp_callback) ==
                HP_WALK_TERMINATE) {
                i_hp_dprintf("hp_traverse: walk terminated.\n");
                return (HP_WALK_TERMINATE);
            }

        if (rv == HP_WALK_PRUNESIBLING)
            break;
    }

    return (0);
}

/*
 * hp_type()
 *
 *  Return a node's type.
 */
int
hp_type(hp_node_t node)
{
    i_hp_dprintf("hp_type: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_type: invalid arguments.\n");
        errno = EINVAL;
        return (-1);
    }

    return (node->hp_type);
}

/*
 * hp_name()
 *
 *  Return a node's name.
 */
char *
hp_name(hp_node_t node)
{
    i_hp_dprintf("hp_name: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_name: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if (node->hp_name == NULL) {
        i_hp_dprintf("hp_name: missing name value.\n");
        errno = EFAULT;
    }

    return (node->hp_name);
}

/*
 * hp_state()
 *
 *  Return a node's current state.
 */
int
hp_state(hp_node_t node)
{
    i_hp_dprintf("hp_state: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_state: invalid arguments.\n");
        errno = EINVAL;
        return (-1);
    }

    if ((node->hp_type != HP_NODE_CONNECTOR) &&
        (node->hp_type != HP_NODE_PORT)) {
        i_hp_dprintf("hp_state: operation not supported.\n");
        errno = ENOTSUP;
        return (-1);
    }

    return (node->hp_state);
}

/*
 * hp_usage()
 *
 *  Return a usage description for usage nodes.
 */
char *
hp_usage(hp_node_t node)
{
    i_hp_dprintf("hp_usage: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_usage: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if (node->hp_type != HP_NODE_USAGE) {
        i_hp_dprintf("hp_usage: operation not supported.\n");
        errno = ENOTSUP;
        return (NULL);
    }

    if (node->hp_usage == NULL) {
        i_hp_dprintf("hp_usage: missing usage value.\n");
        errno = EFAULT;
    }

    return (node->hp_usage);
}

/*
 * hp_description()
 *
 *  Return a type description (e.g. "PCI slot") for connection nodes.
 */
char *
hp_description(hp_node_t node)
{
    i_hp_dprintf("hp_description: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_description: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if ((node->hp_type != HP_NODE_CONNECTOR) &&
        (node->hp_type != HP_NODE_PORT)) {
        i_hp_dprintf("hp_description: operation not supported.\n");
        errno = ENOTSUP;
        return (NULL);
    }

    if (node->hp_description == NULL) {
        i_hp_dprintf("hp_description: missing description value.\n");
        errno = EFAULT;
    }

    return (node->hp_description);
}

/*
 * hp_last_change()
 *
 *  Return when the state of a connection was last changed.
 */
time_t
hp_last_change(hp_node_t node)
{
    i_hp_dprintf("hp_last_change: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_last_change: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if ((node->hp_type != HP_NODE_CONNECTOR) &&
        (node->hp_type != HP_NODE_PORT)) {
        i_hp_dprintf("hp_last_change: operation not supported.\n");
        errno = ENOTSUP;
        return (NULL);
    }

    return (node->hp_last_change);
}

/*
 * hp_parent()
 *
 *  Return a node's parent node.
 */
hp_node_t
hp_parent(hp_node_t node)
{
    i_hp_dprintf("hp_parent: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_parent: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if (node->hp_parent == NULL) {
        i_hp_dprintf("hp_parent: node has no parent.\n");
        errno = ENXIO;
    }

    return (node->hp_parent);
}

/*
 * hp_child()
 *
 *  Return a node's first child node.
 */
hp_node_t
hp_child(hp_node_t node)
{
    i_hp_dprintf("hp_child: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_child: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if (node->hp_child == NULL) {
        i_hp_dprintf("hp_child: node has no child.\n");
        errno = ENXIO;
    }

    return (node->hp_child);
}

/*
 * hp_sibling()
 *
 *  Return a node's next sibling node.
 */
hp_node_t
hp_sibling(hp_node_t node)
{
    i_hp_dprintf("hp_sibling: node=%p\n", (void *)node);

    if (node == NULL) {
        i_hp_dprintf("hp_sibling: invalid arguments.\n");
        errno = EINVAL;
        return (NULL);
    }

    if (node->hp_sibling == NULL) {
        i_hp_dprintf("hp_sibling: node has no sibling.\n");
        errno = ENXIO;
    }

    return (node->hp_sibling);
}

/*
 * hp_path()
 *
 *  Return the path (and maybe connection name) of a node.
 *  The caller must supply two buffers, each MAXPATHLEN size.
 */
int
hp_path(hp_node_t node, char *path, char *connection)
{
    hp_node_t   root;
    hp_node_t   parent;
    int     i;
    char        *s;
    char        components[MAXPATHLEN];

    i_hp_dprintf("hp_path: node=%p, path=%p, connection=%p\n", (void *)node,
        (void *)path, (void *)connection);

    if ((node == NULL) || (path == NULL) || (connection == NULL)) {
        i_hp_dprintf("hp_path: invalid arguments.\n");
        return (EINVAL);
    }

    (void) memset(path, 0, MAXPATHLEN);
    (void) memset(connection, 0, MAXPATHLEN);
    (void) memset(components, 0, MAXPATHLEN);

    /*  Set 'connection' only for connectors and ports */
    if ((node->hp_type == HP_NODE_CONNECTOR) ||
        (node->hp_type == HP_NODE_PORT))
        (void) strlcpy(connection, node->hp_name, MAXPATHLEN);

    /* Trace back to the root node, accumulating components */
    for (parent = node; parent != NULL; parent = parent->hp_parent) {
        if (parent->hp_type == HP_NODE_DEVICE) {
            (void) strlcat(components, "/", MAXPATHLEN);
            (void) strlcat(components, parent->hp_name, MAXPATHLEN);
        }
        if (parent->hp_parent == NULL)
            root = parent;
    }

    /* Ensure the snapshot actually contains a base path */
    if (root->hp_basepath == NULL) {
        i_hp_dprintf("hp_path: missing base pathname.\n");
        return (EFAULT);
    }

    /*
     * Construct the path.  Start with the base path from the root
     * node, then append the accumulated components in reverse order.
     */
    if (strcmp(root->hp_basepath, "/") != 0) {
        (void) strlcat(path, root->hp_basepath, MAXPATHLEN);
        if ((root->hp_type == HP_NODE_DEVICE) &&
            ((s = strrchr(path, '/')) != NULL))
            *s = '\0';
    }
    for (i = strlen(components) - 1; i >= 0; i--) {
        if (components[i] == '/') {
            (void) strlcat(path, &components[i], MAXPATHLEN);
            components[i] = '\0';
        }
    }

    return (0);
}

/*
 * hp_set_state()
 *
 *  Initiate a state change operation on a node.
 */
int
hp_set_state(hp_node_t node, uint_t flags, int state, hp_node_t *resultsp)
{
    hp_node_t   root = NULL;
    nvlist_t    *args;
    nvlist_t    *results;
    int     rv;
    char        path[MAXPATHLEN];
    char        connection[MAXPATHLEN];

    i_hp_dprintf("hp_set_state: node=%p, flags=0x%x, state=0x%x, "
        "resultsp=%p\n", (void *)node, flags, state, (void *)resultsp);

    /* Check arguments */
    if ((node == NULL) || (resultsp == NULL) ||
        !HP_SET_STATE_FLAGS_VALID(flags)) {
        i_hp_dprintf("hp_set_state: invalid arguments.\n");
        return (EINVAL);
    }

    /* Check node type */
    if ((node->hp_type != HP_NODE_CONNECTOR) &&
        (node->hp_type != HP_NODE_PORT)) {
        i_hp_dprintf("hp_set_state: operation not supported.\n");
        return (ENOTSUP);
    }

    /* Check that target state is valid */
    switch (state) {
    case DDI_HP_CN_STATE_PRESENT:
    case DDI_HP_CN_STATE_POWERED:
    case DDI_HP_CN_STATE_ENABLED:
        if (node->hp_type != HP_NODE_CONNECTOR) {
            i_hp_dprintf("hp_set_state: mismatched target.\n");
            return (ENOTSUP);
        }
        break;
    case DDI_HP_CN_STATE_PORT_PRESENT:
    case DDI_HP_CN_STATE_OFFLINE:
    case DDI_HP_CN_STATE_ONLINE:
        if (node->hp_type != HP_NODE_PORT) {
            i_hp_dprintf("hp_set_state: mismatched target.\n");
            return (ENOTSUP);
        }
        break;
    default:
        i_hp_dprintf("hp_set_state: invalid target state.\n");
        return (EINVAL);
    }

    /* Get path and connection of specified node */
    if ((rv = hp_path(node, path, connection)) != 0)
        return (rv);

    /* Build arguments for door call */
    if ((args = i_hp_set_args(HP_CMD_CHANGESTATE, path, connection, flags,
        NULL, state)) == NULL)
        return (ENOMEM);

    /* Make the door call to hotplugd */
    rv = i_hp_call_hotplugd(args, &results);

    /* Arguments no longer needed */
    nvlist_free(args);

    /* Parse additional results, if any */
    if ((rv == 0) && (results != NULL)) {
        rv = i_hp_parse_results(results, &root, NULL);
        nvlist_free(results);
        *resultsp = root;
    }

    /* Done */
    return (rv);
}

/*
 * hp_set_private()
 *
 *  Set bus private options on the hotplug connection
 *  indicated by the given hotplug information node.
 */
int
hp_set_private(hp_node_t node, const char *options, char **resultsp)
{
    int     rv;
    nvlist_t    *args;
    nvlist_t    *results;
    char        *values = NULL;
    char        path[MAXPATHLEN];
    char        connection[MAXPATHLEN];

    i_hp_dprintf("hp_set_private: node=%p, options=%p, resultsp=%p\n",
        (void *)node, (void *)options, (void *)resultsp);

    /* Check arguments */
    if ((node == NULL) || (options == NULL) || (resultsp == NULL)) {
        i_hp_dprintf("hp_set_private: invalid arguments.\n");
        return (EINVAL);
    }

    /* Check node type */
    if (node->hp_type != HP_NODE_CONNECTOR) {
        i_hp_dprintf("hp_set_private: operation not supported.\n");
        return (ENOTSUP);
    }

    /* Initialize results */
    *resultsp = NULL;

    /* Get path and connection of specified node */
    if ((rv = hp_path(node, path, connection)) != 0)
        return (rv);

    /* Build arguments for door call */
    if ((args = i_hp_set_args(HP_CMD_SETPRIVATE, path, connection, 0,
        options, 0)) == NULL)
        return (ENOMEM);

    /* Make the door call to hotplugd */
    rv = i_hp_call_hotplugd(args, &results);

    /* Arguments no longer needed */
    nvlist_free(args);

    /* Parse additional results, if any */
    if ((rv == 0) && (results != NULL)) {
        rv = i_hp_parse_results(results, NULL, &values);
        nvlist_free(results);
        *resultsp = values;
    }

    /* Done */
    return (rv);
}

/*
 * hp_get_private()
 *
 *  Get bus private options on the hotplug connection
 *  indicated by the given hotplug information node.
 */
int
hp_get_private(hp_node_t node, const char *options, char **resultsp)
{
    int     rv;
    nvlist_t    *args;
    nvlist_t    *results;
    char        *values = NULL;
    char        path[MAXPATHLEN];
    char        connection[MAXPATHLEN];

    i_hp_dprintf("hp_get_private: node=%p, options=%p, resultsp=%p\n",
        (void *)node, (void *)options, (void *)resultsp);

    /* Check arguments */
    if ((node == NULL) || (options == NULL) || (resultsp == NULL)) {
        i_hp_dprintf("hp_get_private: invalid arguments.\n");
        return (EINVAL);
    }

    /* Check node type */
    if (node->hp_type != HP_NODE_CONNECTOR) {
        i_hp_dprintf("hp_get_private: operation not supported.\n");
        return (ENOTSUP);
    }

    /* Initialize results */
    *resultsp = NULL;

    /* Get path and connection of specified node */
    if ((rv = hp_path(node, path, connection)) != 0)
        return (rv);

    /* Build arguments for door call */
    if ((args = i_hp_set_args(HP_CMD_GETPRIVATE, path, connection, 0,
        options, 0)) == NULL)
        return (ENOMEM);

    /* Make the door call to hotplugd */
    rv = i_hp_call_hotplugd(args, &results);

    /* Arguments no longer needed */
    nvlist_free(args);

    /* Parse additional results, if any */
    if ((rv == 0) && (results != NULL)) {
        rv = i_hp_parse_results(results, NULL, &values);
        nvlist_free(results);
        *resultsp = values;
    }

    /* Done */
    return (rv);
}

/*
 * hp_pack()
 *
 *  Given the root of a hotplug information snapshot, pack
 *  it into a contiguous byte array so that it is suitable
 *  for network transport.
 */
int
hp_pack(hp_node_t root, char **bufp, size_t *lenp)
{
    hp_node_t   node;
    nvlist_t    *nvl;
    char        *buf;
    size_t      len;
    int     rv;

    i_hp_dprintf("hp_pack: root=%p, bufp=%p, lenp=%p\n", (void *)root,
        (void *)bufp, (void *)lenp);

    if ((root == NULL) || (bufp == NULL) || (lenp == NULL)) {
        i_hp_dprintf("hp_pack: invalid arguments.\n");
        return (EINVAL);
    }

    *lenp = 0;
    *bufp = NULL;

    if (nvlist_alloc(&nvl, 0, 0) != 0) {
        i_hp_dprintf("hp_pack: nvlist_alloc() failed (%s).\n",
            strerror(errno));
        return (ENOMEM);
    }

    if (root->hp_basepath != NULL) {
        rv = nvlist_add_string(nvl, HP_INFO_BASE, root->hp_basepath);
        if (rv != 0) {
            nvlist_free(nvl);
            return (rv);
        }
    }

    for (node = root; node != NULL; node = node->hp_sibling) {
        if ((rv = i_hp_pack_branch(node, &buf, &len)) == 0) {
            rv = nvlist_add_byte_array(nvl, HP_INFO_BRANCH,
                (uchar_t *)buf, len);
            free(buf);
        }
        if (rv != 0) {
            nvlist_free(nvl);
            return (rv);
        }
    }

    len = 0;
    buf = NULL;
    if ((rv = nvlist_pack(nvl, &buf, &len, NV_ENCODE_NATIVE, 0)) == 0) {
        *lenp = len;
        *bufp = buf;
    }

    nvlist_free(nvl);

    return (rv);
}

/*
 * hp_unpack()
 *
 *  Unpack a hotplug information snapshot for normal usage.
 */
int
hp_unpack(char *packed_buf, size_t packed_len, hp_node_t *retp)
{
    hp_node_t   root;
    hp_node_t   root_list = NULL;
    hp_node_t   prev_root = NULL;
    nvlist_t    *nvl = NULL;
    nvpair_t    *nvp;
    char        *basepath = NULL;
    int     rv;

    i_hp_dprintf("hp_unpack: packed_buf=%p, packed_len=%u, retp=%p\n",
        (void *)packed_buf, (uint32_t)packed_len, (void *)retp);

    if ((packed_buf == NULL) || (packed_len == 0) || (retp == NULL)) {
        i_hp_dprintf("hp_unpack: invalid arguments.\n");
        return (EINVAL);
    }

    if ((rv = nvlist_unpack(packed_buf, packed_len, &nvl, 0)) != 0)
        return (rv);

    if (nvlist_next_nvpair(nvl, NULL) == NULL) {
        nvlist_free(nvl);
        errno = EINVAL;
        return (NULL);
    }

    for (nvp = NULL; nvp = nvlist_next_nvpair(nvl, nvp); ) {

        rv = EINVAL;

        if (strcmp(nvpair_name(nvp), HP_INFO_BASE) == 0) {
            char    *val_string;

            if ((rv = nvpair_value_string(nvp, &val_string)) == 0) {
                if ((basepath = strdup(val_string)) == NULL)
                    rv = ENOMEM;
            }

        } else if (strcmp(nvpair_name(nvp), HP_INFO_BRANCH) == 0) {
            size_t      len = 0;
            char        *buf = NULL;

            if ((rv = nvpair_value_byte_array(nvp,
                (uchar_t **)&buf, (uint_t *)&len)) == 0) {
                rv = i_hp_unpack_branch(buf, len, NULL, &root);
            }

            if (rv == 0) {
                if (prev_root) {
                    prev_root->hp_sibling = root;
                } else {
                    root_list = root;
                }
                prev_root = root;
            }
        }

        if (rv != 0) {
            if (basepath)
                free(basepath);
            nvlist_free(nvl);
            hp_fini(root_list);
            *retp = NULL;
            return (rv);
        }
    }

    /* Store the base path in each root node */
    if (basepath) {
        for (root = root_list; root; root = root->hp_sibling)
            root->hp_basepath = basepath;
    }

    nvlist_free(nvl);
    *retp = root_list;
    return (0);
}

/*
 * i_hp_dprintf()
 *
 *  Print debug messages to stderr, but only when the debug flag
 *  (libhotplug_debug) is set.
 */
/*PRINTFLIKE1*/
static void
i_hp_dprintf(const char *fmt, ...)
{
    va_list ap;

    if (libhotplug_debug) {
        va_start(ap, fmt);
        (void) vfprintf(stderr, fmt, ap);
        va_end(ap);
    }
}

/*
 * i_hp_pack_branch()
 *
 *  Pack an individual branch of a hotplug information snapshot.
 */
static int
i_hp_pack_branch(hp_node_t root, char **bufp, size_t *lenp)
{
    hp_node_t   child;
    nvlist_t    *nvl;
    char        *buf;
    size_t      len;
    int     rv;

    *lenp = 0;
    *bufp = NULL;

    /* Allocate an nvlist for this branch */
    if (nvlist_alloc(&nvl, 0, 0) != 0)
        return (ENOMEM);

    /* Pack the root of the branch and add it to the nvlist */
    if ((rv = i_hp_pack_node(root, &buf, &len)) == 0) {
        rv = nvlist_add_byte_array(nvl, HP_INFO_NODE,
            (uchar_t *)buf, len);
        free(buf);
    }
    if (rv != 0) {
        nvlist_free(nvl);
        return (rv);
    }

    /* Pack each subordinate branch, and add it to the nvlist */
    for (child = root->hp_child; child != NULL; child = child->hp_sibling) {
        if ((rv = i_hp_pack_branch(child, &buf, &len)) == 0) {
            rv = nvlist_add_byte_array(nvl, HP_INFO_BRANCH,
                (uchar_t *)buf, len);
            free(buf);
        }
        if (rv != 0) {
            nvlist_free(nvl);
            return (rv);
        }
    }

    /* Pack the resulting nvlist into a single buffer */
    len = 0;
    buf = NULL;
    if ((rv = nvlist_pack(nvl, &buf, &len, NV_ENCODE_NATIVE, 0)) == 0) {
        *lenp = len;
        *bufp = buf;
    }

    /* Free the nvlist */
    nvlist_free(nvl);

    return (rv);
}

/*
 * i_hp_pack_node()
 *
 *  Pack an individual node of a hotplug information snapshot.
 */
static int
i_hp_pack_node(hp_node_t node, char **bufp, size_t *lenp)
{
    nvlist_t    *nvl;
    char        *buf = NULL;
    size_t      len = 0;
    int     rv;

    if (nvlist_alloc(&nvl, 0, 0) != 0)
        return (ENOMEM);

    if ((rv = nvlist_add_uint32(nvl, HP_INFO_TYPE,
        (uint32_t)node->hp_type)) != 0)
        goto fail;

    if ((node->hp_name) &&
        ((rv = nvlist_add_string(nvl, HP_INFO_NAME, node->hp_name)) != 0))
        goto fail;

    if ((node->hp_usage) &&
        ((rv = nvlist_add_string(nvl, HP_INFO_USAGE, node->hp_usage)) != 0))
        goto fail;

    if ((node->hp_description) &&
        ((rv = nvlist_add_string(nvl, HP_INFO_DESC,
        node->hp_description)) != 0))
        goto fail;

    if ((rv = nvlist_add_uint32(nvl, HP_INFO_STATE, node->hp_state)) != 0)
        goto fail;

    if ((node->hp_last_change != 0) &&
        ((rv = nvlist_add_uint32(nvl, HP_INFO_TIME,
        node->hp_last_change)) != 0))
        goto fail;

    if ((rv = nvlist_pack(nvl, &buf, &len, NV_ENCODE_NATIVE, 0)) != 0)
        goto fail;

    *bufp = buf;
    *lenp = len;
    nvlist_free(nvl);
    return (0);

fail:
    *bufp = NULL;
    *lenp = 0;
    nvlist_free(nvl);
    return (rv);
}

/*
 * i_hp_unpack_branch()
 *
 *  Unpack a branch of hotplug information nodes.
 */
static int
i_hp_unpack_branch(char *packed_buf, size_t packed_len, hp_node_t parent,
    hp_node_t *retp)
{
    hp_node_t   node = NULL;
    hp_node_t   child;
    hp_node_t   prev_child = NULL;
    nvlist_t    *nvl = NULL;
    nvpair_t    *nvp;
    char        *buf;
    size_t      len;
    int     rv;

    /* Initialize results */
    *retp = NULL;

    /* Unpack the nvlist for this branch */
    if ((rv = nvlist_unpack(packed_buf, packed_len, &nvl, 0)) != 0)
        return (rv);

    /*
     * Unpack the branch.  The first item in the nvlist is
     * always the root node.  And zero or more subordinate
     * branches may be packed afterward.
     */
    for (nvp = NULL; nvp = nvlist_next_nvpair(nvl, nvp); ) {

        len = 0;
        buf = NULL;

        if (strcmp(nvpair_name(nvp), HP_INFO_NODE) == 0) {

            /* Check that there is only one root node */
            if (node != NULL) {
                hp_fini(node);
                nvlist_free(nvl);
                return (EFAULT);
            }

            if ((rv = nvpair_value_byte_array(nvp, (uchar_t **)&buf,
                (uint_t *)&len)) == 0)
                rv = i_hp_unpack_node(buf, len, parent, &node);

            if (rv != 0) {
                nvlist_free(nvl);
                return (rv);
            }

        } else if (strcmp(nvpair_name(nvp), HP_INFO_BRANCH) == 0) {

            if ((rv = nvpair_value_byte_array(nvp, (uchar_t **)&buf,
                (uint_t *)&len)) == 0)
                rv = i_hp_unpack_branch(buf, len, node, &child);

            if (rv != 0) {
                hp_fini(node);
                nvlist_free(nvl);
                return (rv);
            }

            if (prev_child) {
                prev_child->hp_sibling = child;
            } else {
                node->hp_child = child;
            }
            prev_child = child;
        }
    }

    nvlist_free(nvl);
    *retp = node;
    return (0);
}

/*
 * i_hp_unpack_node()
 *
 *  Unpack an individual hotplug information node.
 */
static int
i_hp_unpack_node(char *buf, size_t len, hp_node_t parent, hp_node_t *retp)
{
    hp_node_t   node;
    nvlist_t    *nvl;
    nvpair_t    *nvp;
    uint32_t    val_uint32;
    char        *val_string;
    int     rv = 0;

    /* Initialize results */
    *retp = NULL;

    /* Unpack node into an nvlist */
    if ((nvlist_unpack(buf, len, &nvl, 0) != 0))
        return (EINVAL);

    /* Allocate the new node */
    if ((node = (hp_node_t)calloc(1, sizeof (struct hp_node))) == NULL) {
        nvlist_free(nvl);
        return (ENOMEM);
    }

    /* Iterate through nvlist, unpacking each field */
    for (nvp = NULL; nvp = nvlist_next_nvpair(nvl, nvp); ) {

        if ((strcmp(nvpair_name(nvp), HP_INFO_TYPE) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_UINT32)) {

            (void) nvpair_value_uint32(nvp, &val_uint32);
            node->hp_type = val_uint32;

        } else if ((strcmp(nvpair_name(nvp), HP_INFO_NAME) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_STRING)) {

            (void) nvpair_value_string(nvp, &val_string);
            if ((node->hp_name = strdup(val_string)) == NULL) {
                rv = ENOMEM;
                break;
            }

        } else if ((strcmp(nvpair_name(nvp), HP_INFO_STATE) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_UINT32)) {

            (void) nvpair_value_uint32(nvp, &val_uint32);
            node->hp_state = val_uint32;

        } else if ((strcmp(nvpair_name(nvp), HP_INFO_USAGE) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_STRING)) {

            (void) nvpair_value_string(nvp, &val_string);
            if ((node->hp_usage = strdup(val_string)) == NULL) {
                rv = ENOMEM;
                break;
            }

        } else if ((strcmp(nvpair_name(nvp), HP_INFO_DESC) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_STRING)) {

            (void) nvpair_value_string(nvp, &val_string);
            if ((node->hp_description = strdup(val_string))
                == NULL) {
                rv = ENOMEM;
                break;
            }

        } else if ((strcmp(nvpair_name(nvp), HP_INFO_TIME) == 0) &&
            (nvpair_type(nvp) == DATA_TYPE_UINT32)) {

            (void) nvpair_value_uint32(nvp, &val_uint32);
            node->hp_last_change = (time_t)val_uint32;

        } else {
            i_hp_dprintf("i_hp_unpack_node: unrecognized: '%s'\n",
                nvpair_name(nvp));
        }
    }

    /* Unpacked nvlist no longer needed */
    nvlist_free(nvl);

    /* Check for errors */
    if (rv != 0) {
        hp_fini(node);
        return (rv);
    }

    /* Success */
    node->hp_parent = parent;
    *retp = node;
    return (0);
}

/*
 * i_hp_call_hotplugd()
 *
 *  Perform a door call to the hotplug daemon.
 */
static int
i_hp_call_hotplugd(nvlist_t *args, nvlist_t **resultsp)
{
    door_arg_t  door_arg;
    nvlist_t    *results = NULL;
    char        *buf = NULL;
    size_t      len = 0;
    uint64_t    seqnum;
    int     door_fd;
    int     rv;

    /* Initialize results */
    *resultsp = NULL;

    /* Open door */
    if ((door_fd = open(HOTPLUGD_DOOR, O_RDONLY)) < 0) {
        i_hp_dprintf("i_hp_call_hotplugd: cannot open door (%s)\n",
            strerror(errno));
        return (EBADF);
    }

    /* Pack the nvlist of arguments */
    if ((rv = nvlist_pack(args, &buf, &len, NV_ENCODE_NATIVE, 0)) != 0) {
        i_hp_dprintf("i_hp_call_hotplugd: cannot pack arguments (%s)\n",
            strerror(rv));
        return (rv);
    }

    /* Set the door argument using the packed arguments */
    door_arg.data_ptr = buf;
    door_arg.data_size = len;
    door_arg.desc_ptr = NULL;
    door_arg.desc_num = 0;
    door_arg.rbuf = (char *)(uintptr_t)&rv;
    door_arg.rsize = sizeof (rv);

    /* Attempt the door call */
    if (door_call(door_fd, &door_arg) != 0) {
        rv = errno;
        i_hp_dprintf("i_hp_call_hotplugd: door call failed (%s)\n",
            strerror(rv));
        (void) close(door_fd);
        free(buf);
        return (rv);
    }

    /* The arguments are no longer needed */
    free(buf);

    /*
     * If results are not in the original buffer provided,
     * then check and process the new results buffer.
     */
    if (door_arg.rbuf != (char *)(uintptr_t)&rv) {

        /*
         * First check that the buffer is valid.  Then check for
         * the simple case where a short result code was sent.
         * The last case is a packed nvlist was returned, which
         * needs to be unpacked.
         */
        if ((door_arg.rbuf == NULL) ||
            (door_arg.data_size < sizeof (rv))) {
            i_hp_dprintf("i_hp_call_hotplugd: invalid results.\n");
            rv = EFAULT;

        } else if (door_arg.data_size == sizeof (rv)) {
            rv = *(int *)(uintptr_t)door_arg.rbuf;

        } else if ((rv = nvlist_unpack(door_arg.rbuf,
            door_arg.data_size, &results, 0)) != 0) {
            i_hp_dprintf("i_hp_call_hotplugd: "
                "cannot unpack results (%s).\n", strerror(rv));
            results = NULL;
            rv = EFAULT;
        }

        /* Unmap the results buffer */
        if (door_arg.rbuf != NULL)
            (void) munmap(door_arg.rbuf, door_arg.rsize);

        /*
         * In the case of a packed nvlist, notify the daemon
         * that it can free the result buffer from its heap.
         */
        if ((results != NULL) &&
            (nvlist_lookup_uint64(results, HPD_SEQNUM, &seqnum) == 0)) {
            door_arg.data_ptr = (char *)(uintptr_t)&seqnum;
            door_arg.data_size = sizeof (seqnum);
            door_arg.desc_ptr = NULL;
            door_arg.desc_num = 0;
            door_arg.rbuf = NULL;
            door_arg.rsize = 0;
            (void) door_call(door_fd, &door_arg);
            if (door_arg.rbuf != NULL)
                (void) munmap(door_arg.rbuf, door_arg.rsize);
        }

        *resultsp = results;
    }

    (void) close(door_fd);
    return (rv);
}

/*
 * i_hp_set_args()
 *
 *  Construct an nvlist of arguments for a hotplugd door call.
 */
static nvlist_t *
i_hp_set_args(hp_cmd_t cmd, const char *path, const char *connection,
    uint_t flags, const char *options, int state)
{
    nvlist_t    *args;

    /* Allocate a new nvlist */
    if (nvlist_alloc(&args, NV_UNIQUE_NAME_TYPE, 0) != 0)
        return (NULL);

    /* Add common arguments */
    if ((nvlist_add_int32(args, HPD_CMD, cmd) != 0) ||
        (nvlist_add_string(args, HPD_PATH, path) != 0)) {
        nvlist_free(args);
        return (NULL);
    }

    /* Add connection, but only if defined */
    if ((connection != NULL) && (connection[0] != '\0') &&
        (nvlist_add_string(args, HPD_CONNECTION, connection) != 0)) {
        nvlist_free(args);
        return (NULL);
    }

    /* Add flags, but only if defined */
    if ((flags != 0) && (nvlist_add_uint32(args, HPD_FLAGS, flags) != 0)) {
        nvlist_free(args);
        return (NULL);
    }

    /* Add options, but only if defined */
    if ((options != NULL) &&
        (nvlist_add_string(args, HPD_OPTIONS, options) != 0)) {
        nvlist_free(args);
        return (NULL);
    }

    /* Add state, but only for CHANGESTATE command */
    if ((cmd == HP_CMD_CHANGESTATE) &&
        (nvlist_add_int32(args, HPD_STATE, state) != 0)) {
        nvlist_free(args);
        return (NULL);
    }

    return (args);
}

/*
 * i_hp_parse_results()
 *
 *  Parse out individual fields of an nvlist of results from
 *  a hotplugd door call.
 */
static int
i_hp_parse_results(nvlist_t *results, hp_node_t *rootp, char **optionsp)
{
    int rv;

    /* Parse an information snapshot */
    if (rootp) {
        char    *buf = NULL;
        size_t  len = 0;

        *rootp = NULL;
        if (nvlist_lookup_byte_array(results, HPD_INFO,
            (uchar_t **)&buf, (uint_t *)&len) == 0) {
            if ((rv = hp_unpack(buf, len, rootp)) != 0)
                return (rv);
        }
    }

    /* Parse a bus private option string */
    if (optionsp) {
        char    *str;

        *optionsp = NULL;
        if ((nvlist_lookup_string(results, HPD_OPTIONS, &str) == 0) &&
            ((*optionsp = strdup(str)) == NULL)) {
            return (ENOMEM);
        }
    }

    /* Parse result code of the operation */
    if (nvlist_lookup_int32(results, HPD_STATUS, &rv) != 0) {
        i_hp_dprintf("i_hp_call_hotplugd: missing status.\n");
        return (EFAULT);
    }

    return (rv);
}