cmd/hotplugd/hotplugd_rcm.c

	hotplugd_rcm.c revision 269473047d747f7815af570197e4ef7322d3632c
/*
 * 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 <unistd.h>
#include <errno.h>
#include <string.h>
#include <librcm.h>
#include <libhotplug.h>
#include <libhotplug_impl.h>
#include <sys/sunddi.h>
#include <sys/ddi_hp.h>
#include "hotplugd_impl.h"

/*
 * Define structures for a path-to-usage lookup table.
 */
typedef struct info_entry {
    char            *rsrc;
    char            *usage;
    struct info_entry   *next;
} info_entry_t;

typedef struct {
    char        *path;
    info_entry_t    *entries;
} info_table_t;

/*
 * Define callback argument used when getting resources.
 */
typedef struct {
    int error;
    int n_rsrcs;
    char    **rsrcs;
    char    path[MAXPATHLEN];
    char    connection[MAXPATHLEN];
    char    dev_path[MAXPATHLEN];
} resource_cb_arg_t;

/*
 * Define callback argument used when merging info.
 */
typedef struct {
    int     error;
    info_table_t    *table;
    size_t      table_len;
    char        path[MAXPATHLEN];
    char        connection[MAXPATHLEN];
} merge_cb_arg_t;

/*
 * Local functions.
 */
static int  merge_rcm_info(hp_node_t root, rcm_info_t *info);
static int  get_rcm_usage(char **rsrcs, rcm_info_t **info_p);
static int  build_table(rcm_info_t *info, info_table_t **tablep,
            size_t *table_lenp);
static void free_table(info_table_t *table, size_t table_len);
static int  resource_callback(hp_node_t node, void *argp);
static int  merge_callback(hp_node_t node, void *argp);
static int  rsrc2path(const char *rsrc, char *path);
static int  compare_info(const void *a, const void *b);

/*
 * copy_usage()
 *
 *  Given an information snapshot, get the corresponding
 *  RCM usage information and merge it into the snapshot.
 */
int
copy_usage(hp_node_t root)
{
    rcm_info_t  *info = NULL;
    char        **rsrcs = NULL;
    int     rv;

    /* Get resource names */
    if ((rv = rcm_resources(root, &rsrcs)) != 0) {
        log_err("Cannot get RCM resources (%s)\n", strerror(rv));
        return (rv);
    }

    /* Do nothing if no resources */
    if (rsrcs == NULL)
        return (0);

    /* Get RCM usage information */
    if ((rv = get_rcm_usage(rsrcs, &info)) != 0) {
        log_err("Cannot get RCM information (%s)\n", strerror(rv));
        free_rcm_resources(rsrcs);
        return (rv);
    }

    /* Done with resource names */
    free_rcm_resources(rsrcs);

    /* If there is RCM usage information, merge it in */
    if (info != NULL) {
        rv = merge_rcm_info(root, info);
        rcm_free_info(info);
        return (rv);
    }

    return (0);
}

/*
 * rcm_resources()
 *
 *  Given the root of a hotplug information snapshot,
 *  construct a list of RCM compatible resource names.
 */
int
rcm_resources(hp_node_t root, char ***rsrcsp)
{
    resource_cb_arg_t   arg;

    /* Initialize results */
    *rsrcsp = NULL;

    /* Traverse snapshot to get resources */
    (void) memset(&arg, 0, sizeof (resource_cb_arg_t));
    (void) hp_traverse(root, &arg, resource_callback);

    /* Check for errors */
    if (arg.error != 0) {
        free_rcm_resources(arg.rsrcs);
        return (arg.error);
    }

    /* Success */
    *rsrcsp = arg.rsrcs;
    return (0);
}

/*
 * free_rcm_resources()
 *
 *  Free a table of RCM resource names.
 */
void
free_rcm_resources(char **rsrcs)
{
    int i;

    if (rsrcs != NULL) {
        for (i = 0; rsrcs[i] != NULL; i++)
            free(rsrcs[i]);
        free(rsrcs);
    }
}

/*
 * rcm_offline()
 *
 *  Implement an RCM offline request.
 *
 *  NOTE: errors from RCM will be merged into the snapshot.
 */
int
rcm_offline(char **rsrcs, uint_t flags, hp_node_t root)
{
    rcm_handle_t    *handle;
    rcm_info_t  *info = NULL;
    uint_t      rcm_flags = 0;
    int     rv = 0;

    dprintf("rcm_offline()\n");

    /* Set flags */
    if (flags & HPFORCE)
        rcm_flags |= RCM_FORCE;
    if (flags & HPQUERY)
        rcm_flags |= RCM_QUERY;

    /* Allocate RCM handle */
    if (rcm_alloc_handle(NULL, 0, NULL, &handle) != RCM_SUCCESS) {
        log_err("Cannot allocate RCM handle (%s)\n", strerror(errno));
        return (EFAULT);
    }

    /* Request RCM offline */
    if (rcm_request_offline_list(handle, rsrcs, rcm_flags,
        &info) != RCM_SUCCESS)
        rv = EBUSY;

    /* RCM handle is no longer needed */
    (void) rcm_free_handle(handle);

    /*
     * Check if RCM returned any information tuples.  If so,
     * then also check if the RCM operation failed, and possibly
     * merge the RCM info into the caller's hotplug snapshot.
     */
    if (info != NULL) {
        if (rv != 0)
            (void) merge_rcm_info(root, info);
        rcm_free_info(info);
    }

    return (rv);
}

/*
 * rcm_online()
 *
 *  Implement an RCM online notification.
 */
void
rcm_online(char **rsrcs)
{
    rcm_handle_t    *handle;
    rcm_info_t  *info = NULL;

    dprintf("rcm_online()\n");

    if (rcm_alloc_handle(NULL, 0, NULL, &handle) != RCM_SUCCESS) {
        log_err("Cannot allocate RCM handle (%s)\n", strerror(errno));
        return;
    }

    (void) rcm_notify_online_list(handle, rsrcs, 0, &info);

    (void) rcm_free_handle(handle);

    if (info != NULL)
        rcm_free_info(info);
}

/*
 * rcm_remove()
 *
 *  Implement an RCM remove notification.
 */
void
rcm_remove(char **rsrcs)
{
    rcm_handle_t    *handle;
    rcm_info_t  *info = NULL;

    dprintf("rcm_remove()\n");

    if (rcm_alloc_handle(NULL, 0, NULL, &handle) != RCM_SUCCESS) {
        log_err("Cannot allocate RCM handle (%s)\n", strerror(errno));
        return;
    }

    (void) rcm_notify_remove_list(handle, rsrcs, 0, &info);

    (void) rcm_free_handle(handle);

    if (info != NULL)
        rcm_free_info(info);
}

/*
 * get_rcm_usage()
 *
 *  Lookup usage information for a set of resources from RCM.
 */
static int
get_rcm_usage(char **rsrcs, rcm_info_t **info_p)
{
    rcm_handle_t    *handle;
    rcm_info_t  *info = NULL;
    int     rv = 0;

    /* No-op if no RCM resources */
    if (rsrcs == NULL)
        return (0);

    /* Allocate RCM handle */
    if (rcm_alloc_handle(NULL, RCM_NOPID, NULL, &handle) != RCM_SUCCESS) {
        log_err("Cannot allocate RCM handle (%s)\n", strerror(errno));
        return (EFAULT);
    }

    /* Get usage information from RCM */
    if (rcm_get_info_list(handle, rsrcs,
        RCM_INCLUDE_DEPENDENT | RCM_INCLUDE_SUBTREE,
        &info) != RCM_SUCCESS) {
        log_err("Failed to get RCM information (%s)\n",
            strerror(errno));
        rv = EFAULT;
    }

    /* RCM handle is no longer needed */
    (void) rcm_free_handle(handle);

    *info_p = info;
    return (rv);
}

/*
 * merge_rcm_info()
 *
 *  Merge RCM information into a hotplug information snapshot.
 *  First a lookup table is built to map lists of RCM usage to
 *  pathnames.  Then during a full traversal of the snapshot,
 *  the lookup table is used for each node to find matching
 *  RCM info tuples for each path in the snapshot.
 */
static int
merge_rcm_info(hp_node_t root, rcm_info_t *info)
{
    merge_cb_arg_t      arg;
    info_table_t        *table;
    size_t          table_len;
    int         rv;

    /* Build a lookup table, mapping paths to usage information */
    if ((rv = build_table(info, &table, &table_len)) != 0) {
        log_err("Cannot build RCM lookup table (%s)\n", strerror(rv));
        return (rv);
    }

    /* Stop if no valid entries were inserted in table */
    if ((table == NULL) || (table_len == 0)) {
        log_err("Unable to gather RCM usage.\n");
        return (0);
    }

    /* Initialize callback argument */
    (void) memset(&arg, 0, sizeof (merge_cb_arg_t));
    arg.table = table;
    arg.table_len = table_len;

    /* Perform a merge traversal */
    (void) hp_traverse(root, (void *)&arg, merge_callback);

    /* Done with the table */
    free_table(table, table_len);

    /* Check for errors */
    if (arg.error != 0) {
        log_err("Cannot merge RCM information (%s)\n", strerror(rv));
        return (rv);
    }

    return (0);
}

/*
 * resource_callback()
 *
 *  A callback function for hp_traverse() that builds an RCM
 *  compatible list of resource path names.  The array has
 *  been pre-allocated based on results from the related
 *  callback resource_count_callback().
 */
static int
resource_callback(hp_node_t node, void *argp)
{
    resource_cb_arg_t   *arg = (resource_cb_arg_t *)argp;
    char            **new_rsrcs;
    size_t          new_size;
    int         type;

    /* Get node type */
    type = hp_type(node);

    /* Prune OFFLINE ports */
    if ((type == HP_NODE_PORT) && HP_IS_OFFLINE(hp_state(node)))
        return (HP_WALK_PRUNECHILD);

    /* Skip past non-devices */
    if (type != HP_NODE_DEVICE)
        return (HP_WALK_CONTINUE);

    /* Lookup resource path */
    if (hp_path(node, arg->path, arg->connection) != 0) {
        log_err("Cannot get RCM resource path.\n");
        arg->error = EFAULT;
        return (HP_WALK_TERMINATE);
    }

    /* Insert "/devices" to path name */
    (void) snprintf(arg->dev_path, MAXPATHLEN, "/devices%s", arg->path);

    /*
     * Grow resource array to accomodate new /devices path.
     * NOTE: include an extra NULL pointer at end of array.
     */
    new_size = (arg->n_rsrcs + 2) * sizeof (char *);
    if (arg->rsrcs == NULL)
        new_rsrcs = (char **)malloc(new_size);
    else
        new_rsrcs = (char **)realloc(arg->rsrcs, new_size);
    if (new_rsrcs != NULL) {
        arg->rsrcs = new_rsrcs;
    } else {
        log_err("Cannot allocate RCM resource array.\n");
        arg->error = ENOMEM;
        return (HP_WALK_TERMINATE);
    }

    /* Initialize new entries */
    arg->rsrcs[arg->n_rsrcs] = strdup(arg->dev_path);
    arg->rsrcs[arg->n_rsrcs + 1] = NULL;

    /* Check for errors */
    if (arg->rsrcs[arg->n_rsrcs] == NULL) {
        log_err("Cannot allocate RCM resource path.\n");
        arg->error = ENOMEM;
        return (HP_WALK_TERMINATE);
    }

    /* Increment resource count */
    arg->n_rsrcs += 1;

    /* Do not visit children */
    return (HP_WALK_PRUNECHILD);
}

/*
 * merge_callback()
 *
 *  A callback function for hp_traverse() that merges RCM information
 *  tuples into an existing hotplug information snapshot.  The RCM
 *  information will be turned into HP_NODE_USAGE nodes.
 */
static int
merge_callback(hp_node_t node, void *argp)
{
    merge_cb_arg_t  *arg = (merge_cb_arg_t *)argp;
    hp_node_t   usage;
    info_table_t    lookup;
    info_table_t    *slot;
    info_entry_t    *entry;
    int     rv;

    /* Only process device nodes (other nodes cannot have usage) */
    if (hp_type(node) != HP_NODE_DEVICE)
        return (HP_WALK_CONTINUE);

    /* Get path of current node, using buffer provided in 'arg' */
    if ((rv = hp_path(node, arg->path, arg->connection)) != 0) {
        log_err("Cannot lookup hotplug path (%s)\n", strerror(rv));
        arg->error = rv;
        return (HP_WALK_TERMINATE);
    }

    /* Check the lookup table for associated usage */
    lookup.path = arg->path;
    if ((slot = bsearch(&lookup, arg->table, arg->table_len,
        sizeof (info_table_t), compare_info)) == NULL)
        return (HP_WALK_CONTINUE);

    /* Usage information was found.  Append HP_NODE_USAGE nodes. */
    for (entry = slot->entries; entry != NULL; entry = entry->next) {

        /* Allocate a new usage node */
        usage = (hp_node_t)calloc(1, sizeof (struct hp_node));
        if (usage == NULL) {
            log_err("Cannot allocate hotplug usage node.\n");
            arg->error = ENOMEM;
            return (HP_WALK_TERMINATE);
        }

        /* Initialize the usage node's contents */
        usage->hp_type = HP_NODE_USAGE;
        if ((usage->hp_name = strdup(entry->rsrc)) == NULL) {
            log_err("Cannot allocate hotplug usage node name.\n");
            free(usage);
            arg->error = ENOMEM;
            return (HP_WALK_TERMINATE);
        }
        if ((usage->hp_usage = strdup(entry->usage)) == NULL) {
            log_err("Cannot allocate hotplug usage node info.\n");
            free(usage->hp_name);
            free(usage);
            arg->error = ENOMEM;
            return (HP_WALK_TERMINATE);
        }

        /* Link the usage node as a child of the device node */
        usage->hp_parent = node;
        usage->hp_sibling = node->hp_child;
        node->hp_child = usage;
    }

    return (HP_WALK_CONTINUE);
}

/*
 * build_table()
 *
 *  Build a lookup table that will be used to map paths to their
 *  corresponding RCM information tuples.
 */
static int
build_table(rcm_info_t *info, info_table_t **tablep, size_t *table_lenp)
{
    rcm_info_tuple_t    *tuple;
    info_entry_t        *entry;
    info_table_t        *slot;
    info_table_t        *table;
    size_t          table_len;
    const char      *rsrc;
    const char      *usage;
    char            path[MAXPATHLEN];

    /* Initialize results */
    *tablep = NULL;
    *table_lenp = 0;

    /* Count the RCM info tuples to determine the table's size */
    table_len = 0;
    for (tuple = NULL; (tuple = rcm_info_next(info, tuple)) != NULL; )
        table_len++;

    /* If the table would be empty, then do nothing */
    if (table_len == 0)
        return (ENOENT);

    /* Allocate the lookup table */
    table = (info_table_t *)calloc(table_len, sizeof (info_table_t));
    if (table == NULL)
        return (ENOMEM);

    /*
     * Fill in the lookup table.  Fill one slot in the table
     * for each device path that has a set of associated RCM
     * information tuples.  In some cases multiple tuples will
     * be joined together within the same slot.
     */
    slot = NULL;
    table_len = 0;
    for (tuple = NULL; (tuple = rcm_info_next(info, tuple)) != NULL; ) {

        /*
         * Extract RCM resource name and usage description.
         *
         * NOTE: skip invalid tuples to return as much as possible.
         */
        if (((rsrc = rcm_info_rsrc(tuple)) == NULL) ||
            ((usage = rcm_info_info(tuple)) == NULL)) {
            log_err("RCM returned invalid resource or usage.\n");
            continue;
        }

        /*
         * Try to convert the RCM resource name to a hotplug path.
         * If conversion succeeds and this path differs from the
         * current slot in the table, then initialize the next
         * slot in the table.
         */
        if ((rsrc2path(rsrc, path) == 0) &&
            ((slot == NULL) || (strcmp(slot->path, path) != 0))) {
            slot = &table[table_len];
            if ((slot->path = strdup(path)) == NULL) {
                log_err("Cannot build info table slot.\n");
                free_table(table, table_len);
                return (ENOMEM);
            }
            table_len++;
        }

        /* Append current usage to entry list in the current slot */
        if (slot != NULL) {

            /* Allocate new entry */
            entry = (info_entry_t *)malloc(sizeof (info_entry_t));
            if (entry == NULL) {
                log_err("Cannot allocate info table entry.\n");
                free_table(table, table_len);
                return (ENOMEM);
            }

            /* Link entry into current slot list */
            entry->next = slot->entries;
            slot->entries = entry;

            /* Initialize entry values */
            if (((entry->rsrc = strdup(rsrc)) == NULL) ||
                ((entry->usage = strdup(usage)) == NULL)) {
                log_err("Cannot build info table entry.\n");
                free_table(table, table_len);
                return (ENOMEM);
            }
        }
    }

    /* Check if valid entries were inserted in table */
    if (table_len == 0) {
        free(table);
        return (0);
    }

    /* Sort the lookup table by hotplug path */
    qsort(table, table_len, sizeof (info_table_t), compare_info);

    /* Done */
    *tablep = table;
    *table_lenp = table_len;
    return (0);
}

/*
 * free_table()
 *
 *  Destroy a lookup table.
 */
static void
free_table(info_table_t *table, size_t table_len)
{
    info_entry_t    *entry;
    int     index;

    if (table != NULL) {
        for (index = 0; index < table_len; index++) {
            if (table[index].path != NULL)
                free(table[index].path);
            while (table[index].entries != NULL) {
                entry = table[index].entries;
                table[index].entries = entry->next;
                if (entry->rsrc != NULL)
                    free(entry->rsrc);
                if (entry->usage != NULL)
                    free(entry->usage);
                free(entry);
            }
        }
        free(table);
    }
}

/*
 * rsrc2path()
 *
 *  Convert from an RCM resource name to a hotplug device path.
 */
static int
rsrc2path(const char *rsrc, char *path)
{
    char    *s;
    char    tmp[MAXPATHLEN];

    /* Only convert /dev and /devices paths */
    if (strncmp(rsrc, "/dev", 4) == 0) {

        /* Follow symbolic links for /dev paths */
        if (realpath(rsrc, tmp) == NULL) {
            log_err("Cannot resolve RCM resource (%s)\n",
                strerror(errno));
            return (-1);
        }

        /* Remove the leading "/devices" part */
        (void) strlcpy(path, &tmp[strlen(S_DEVICES)], MAXPATHLEN);

        /* Remove any trailing minor node part */
        if ((s = strrchr(path, ':')) != NULL)
            *s = '\0';

        /* Successfully converted */
        return (0);
    }

    /* Not converted */
    return (-1);
}

/*
 * compare_info()
 *
 *  Compare two slots in the lookup table that maps paths to usage.
 *
 *  NOTE: for use with qsort() and bsearch().
 */
static int
compare_info(const void *a, const void *b)
{
    info_table_t    *slot_a = (info_table_t *)a;
    info_table_t    *slot_b = (info_table_t *)b;

    return (strcmp(slot_a->path, slot_b->path));
}