membership.c

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/*
 * Copyright 2004-2021 the Pacemaker project contributors
 *
 * The version control history for this file may have further details.
 *
 * This source code is licensed under the GNU Lesser General Public License
 * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
 */

#include <crm_internal.h>

#ifndef _GNU_SOURCE
#  define _GNU_SOURCE
#endif

#include <sys/param.h>
#include <sys/types.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <glib.h>
#include <crm/common/ipc.h>
#include <crm/common/xml_internal.h>
#include <crm/cluster/internal.h>
#include <crm/msg_xml.h>
#include <crm/stonith-ng.h>
#include "crmcluster_private.h"

/* The peer cache remembers cluster nodes that have been seen.
 * This is managed mostly automatically by libcluster, based on
 * cluster membership events.
 *
 * Because cluster nodes can have conflicting names or UUIDs,
 * the hash table key is a uniquely generated ID.
 */
GHashTable *crm_peer_cache = NULL;

/*
 * The remote peer cache tracks pacemaker_remote nodes. While the
 * value has the same type as the peer cache's, it is tracked separately for
 * three reasons: pacemaker_remote nodes can't have conflicting names or UUIDs,
 * so the name (which is also the UUID) is used as the hash table key; there
 * is no equivalent of membership events, so management is not automatic; and
 * most users of the peer cache need to exclude pacemaker_remote nodes.
 *
 * That said, using a single cache would be more logical and less error-prone,
 * so it would be a good idea to merge them one day.
 *
 * libcluster provides two avenues for populating the cache:
 * crm_remote_peer_get() and crm_remote_peer_cache_remove() directly manage it,
 * while crm_remote_peer_cache_refresh() populates it via the CIB.
 */
GHashTable *crm_remote_peer_cache = NULL;

/*
 * The known node cache tracks cluster and remote nodes that have been seen in
 * the CIB. It is useful mainly when a caller needs to know about a node that
 * may no longer be in the membership, but doesn't want to add the node to the
 * main peer cache tables.
 */
static GHashTable *known_node_cache = NULL;

unsigned long long crm_peer_seq = 0;
gboolean crm_have_quorum = FALSE;
static gboolean crm_autoreap  = TRUE;

// Flag setting and clearing for crm_node_t:flags

#define set_peer_flags(peer, flags_to_set) do {                               \
        (peer)->flags = pcmk__set_flags_as(__func__, __LINE__, LOG_TRACE,     \
                                           "Peer", (peer)->uname,             \
                                           (peer)->flags, (flags_to_set),     \
                                           #flags_to_set);                    \
    } while (0)

#define clear_peer_flags(peer, flags_to_clear) do {                           \
        (peer)->flags = pcmk__clear_flags_as(__func__, __LINE__,              \
                                             LOG_TRACE,                       \
                                             "Peer", (peer)->uname,           \
                                             (peer)->flags, (flags_to_clear), \
                                             #flags_to_clear);                \
    } while (0)

static void update_peer_uname(crm_node_t *node, const char *uname);

int
crm_remote_peer_cache_size(void)
{
    if (crm_remote_peer_cache == NULL) {
        return 0;
    }
    return g_hash_table_size(crm_remote_peer_cache);
}

crm_node_t *
crm_remote_peer_get(const char *node_name)
{
    crm_node_t *node;

    if (node_name == NULL) {
        errno = -EINVAL;
        return NULL;
    }

    /* Return existing cache entry if one exists */
    node = g_hash_table_lookup(crm_remote_peer_cache, node_name);
    if (node) {
        return node;
    }

    /* Allocate a new entry */
    node = calloc(1, sizeof(crm_node_t));
    if (node == NULL) {
        return NULL;
    }

    /* Populate the essential information */
    set_peer_flags(node, crm_remote_node);
    node->uuid = strdup(node_name);
    if (node->uuid == NULL) {
        free(node);
        errno = -ENOMEM;
        return NULL;
    }

    /* Add the new entry to the cache */
    g_hash_table_replace(crm_remote_peer_cache, node->uuid, node);
    crm_trace("added %s to remote cache", node_name);

    /* Update the entry's uname, ensuring peer status callbacks are called */
    update_peer_uname(node, node_name);
    return node;
}

void
crm_remote_peer_cache_remove(const char *node_name)
{
    if (g_hash_table_remove(crm_remote_peer_cache, node_name)) {
        crm_trace("removed %s from remote peer cache", node_name);
    }
}

static const char *
remote_state_from_cib(xmlNode *node_state)
{
    const char *status;

    status = crm_element_value(node_state, XML_NODE_IN_CLUSTER);
    if (status && !crm_is_true(status)) {
        status = CRM_NODE_LOST;
    } else {
        status = CRM_NODE_MEMBER;
    }
    return status;
}

/* user data for looping through remote node xpath searches */
struct refresh_data {
    const char *field;  /* XML attribute to check for node name */
    gboolean has_state; /* whether to update node state based on XML */
};

static void
remote_cache_refresh_helper(xmlNode *result, void *user_data)
{
    struct refresh_data *data = user_data;
    const char *remote = crm_element_value(result, data->field);
    const char *state = NULL;
    crm_node_t *node;

    CRM_CHECK(remote != NULL, return);

    /* Determine node's state, if the result has it */
    if (data->has_state) {
        state = remote_state_from_cib(result);
    }

    /* Check whether cache already has entry for node */
    node = g_hash_table_lookup(crm_remote_peer_cache, remote);

    if (node == NULL) {
        /* Node is not in cache, so add a new entry for it */
        node = crm_remote_peer_get(remote);
        CRM_ASSERT(node);
        if (state) {
            pcmk__update_peer_state(__func__, node, state, 0);
        }

    } else if (pcmk_is_set(node->flags, crm_node_dirty)) {
        /* Node is in cache and hasn't been updated already, so mark it clean */
        clear_peer_flags(node, crm_node_dirty);
        if (state) {
            pcmk__update_peer_state(__func__, node, state, 0);
        }
    }
}

static void
mark_dirty(gpointer key, gpointer value, gpointer user_data)
{
    set_peer_flags((crm_node_t *) value, crm_node_dirty);
}

static gboolean
is_dirty(gpointer key, gpointer value, gpointer user_data)
{
    return pcmk_is_set(((crm_node_t*)value)->flags, crm_node_dirty);
}

void
crm_remote_peer_cache_refresh(xmlNode *cib)
{
    struct refresh_data data;

    crm_peer_init();

    /* First, we mark all existing cache entries as dirty,
     * so that later we can remove any that weren't in the CIB.
     * We don't empty the cache, because we need to detect changes in state.
     */
    g_hash_table_foreach(crm_remote_peer_cache, mark_dirty, NULL);

    /* Look for guest nodes and remote nodes in the status section */
    data.field = "id";
    data.has_state = TRUE;
    crm_foreach_xpath_result(cib, PCMK__XP_REMOTE_NODE_STATUS,
                             remote_cache_refresh_helper, &data);

    /* Look for guest nodes and remote nodes in the configuration section,
     * because they may have just been added and not have a status entry yet.
     * In that case, the cached node state will be left NULL, so that the
     * peer status callback isn't called until we're sure the node started
     * successfully.
     */
    data.field = "value";
    data.has_state = FALSE;
    crm_foreach_xpath_result(cib, PCMK__XP_GUEST_NODE_CONFIG,
                             remote_cache_refresh_helper, &data);
    data.field = "id";
    data.has_state = FALSE;
    crm_foreach_xpath_result(cib, PCMK__XP_REMOTE_NODE_CONFIG,
                             remote_cache_refresh_helper, &data);

    /* Remove all old cache entries that weren't seen in the CIB */
    g_hash_table_foreach_remove(crm_remote_peer_cache, is_dirty, NULL);
}

gboolean
crm_is_peer_active(const crm_node_t * node)
{
    if(node == NULL) {
        return FALSE;
    }

    if (pcmk_is_set(node->flags, crm_remote_node)) {
        /* remote nodes are never considered active members. This
         * guarantees they will never be considered for DC membership.*/
        return FALSE;
    }
#if SUPPORT_COROSYNC
    if (is_corosync_cluster()) {
        return crm_is_corosync_peer_active(node);
    }
#endif
    crm_err("Unhandled cluster type: %s", name_for_cluster_type(get_cluster_type()));
    return FALSE;
}

static gboolean
crm_reap_dead_member(gpointer key, gpointer value, gpointer user_data)
{
    crm_node_t *node = value;
    crm_node_t *search = user_data;

    if (search == NULL) {
        return FALSE;

    } else if (search->id && node->id != search->id) {
        return FALSE;

    } else if (search->id == 0 && !pcmk__str_eq(node->uname, search->uname, pcmk__str_casei)) {
        return FALSE;

    } else if (crm_is_peer_active(value) == FALSE) {
        crm_info("Removing node with name %s and id %u from membership cache",
                 (node->uname? node->uname : "unknown"), node->id);
        return TRUE;
    }
    return FALSE;
}

guint
reap_crm_member(uint32_t id, const char *name)
{
    int matches = 0;
    crm_node_t search;

    if (crm_peer_cache == NULL) {
        crm_trace("Membership cache not initialized, ignoring purge request");
        return 0;
    }

    search.id = id;
    search.uname = name ? strdup(name) : NULL;
    matches = g_hash_table_foreach_remove(crm_peer_cache, crm_reap_dead_member, &search);
    if(matches) {
        crm_notice("Purged %d peer%s with id=%u%s%s from the membership cache",
                   matches, pcmk__plural_s(matches), search.id,
                   (search.uname? " and/or uname=" : ""),
                   (search.uname? search.uname : ""));

    } else {
        crm_info("No peers with id=%u%s%s to purge from the membership cache",
                 search.id, (search.uname? " and/or uname=" : ""),
                 (search.uname? search.uname : ""));
    }

    free(search.uname);
    return matches;
}

static void
count_peer(gpointer key, gpointer value, gpointer user_data)
{
    guint *count = user_data;
    crm_node_t *node = value;

    if (crm_is_peer_active(node)) {
        *count = *count + 1;
    }
}

guint
crm_active_peers(void)
{
    guint count = 0;

    if (crm_peer_cache) {
        g_hash_table_foreach(crm_peer_cache, count_peer, &count);
    }
    return count;
}

static void
destroy_crm_node(gpointer data)
{
    crm_node_t *node = data;

    crm_trace("Destroying entry for node %u: %s", node->id, node->uname);

    free(node->uname);
    free(node->state);
    free(node->uuid);
    free(node->expected);
    free(node);
}

void
crm_peer_init(void)
{
    if (crm_peer_cache == NULL) {
        crm_peer_cache = pcmk__strikey_table(free, destroy_crm_node);
    }

    if (crm_remote_peer_cache == NULL) {
        crm_remote_peer_cache = pcmk__strikey_table(NULL, destroy_crm_node);
    }

    if (known_node_cache == NULL) {
        known_node_cache = pcmk__strikey_table(free, destroy_crm_node);
    }
}

void
crm_peer_destroy(void)
{
    if (crm_peer_cache != NULL) {
        crm_trace("Destroying peer cache with %d members", g_hash_table_size(crm_peer_cache));
        g_hash_table_destroy(crm_peer_cache);
        crm_peer_cache = NULL;
    }

    if (crm_remote_peer_cache != NULL) {
        crm_trace("Destroying remote peer cache with %d members", g_hash_table_size(crm_remote_peer_cache));
        g_hash_table_destroy(crm_remote_peer_cache);
        crm_remote_peer_cache = NULL;
    }

    if (known_node_cache != NULL) {
        crm_trace("Destroying known node cache with %d members",
                  g_hash_table_size(known_node_cache));
        g_hash_table_destroy(known_node_cache);
        known_node_cache = NULL;
    }

}

static void (*peer_status_callback)(enum crm_status_type, crm_node_t *,
                                    const void *) = NULL;

void
crm_set_status_callback(void (*dispatch) (enum crm_status_type, crm_node_t *, const void *))
{
    peer_status_callback = dispatch;
}

void
crm_set_autoreap(gboolean autoreap)
{
    crm_autoreap = autoreap;
}

static void
dump_peer_hash(int level, const char *caller)
{
    GHashTableIter iter;
    const char *id = NULL;
    crm_node_t *node = NULL;

    g_hash_table_iter_init(&iter, crm_peer_cache);
    while (g_hash_table_iter_next(&iter, (gpointer *) &id, (gpointer *) &node)) {
        do_crm_log(level, "%s: Node %u/%s = %p - %s", caller, node->id, node->uname, node, id);
    }
}

static gboolean
hash_find_by_data(gpointer key, gpointer value, gpointer user_data)
{
    return value == user_data;
}

crm_node_t *
pcmk__search_node_caches(unsigned int id, const char *uname, uint32_t flags)
{
    crm_node_t *node = NULL;

    CRM_ASSERT(id > 0 || uname != NULL);

    crm_peer_init();

    if ((uname != NULL) && pcmk_is_set(flags, CRM_GET_PEER_REMOTE)) {
        node = g_hash_table_lookup(crm_remote_peer_cache, uname);
    }

    if ((node == NULL) && pcmk_is_set(flags, CRM_GET_PEER_CLUSTER)) {
        node = pcmk__search_cluster_node_cache(id, uname);
    }
    return node;
}

crm_node_t *
crm_get_peer_full(unsigned int id, const char *uname, int flags)
{
    crm_node_t *node = NULL;

    CRM_ASSERT(id > 0 || uname != NULL);

    crm_peer_init();

    if (pcmk_is_set(flags, CRM_GET_PEER_REMOTE)) {
        node = g_hash_table_lookup(crm_remote_peer_cache, uname);
    }

    if ((node == NULL) && pcmk_is_set(flags, CRM_GET_PEER_CLUSTER)) {
        node = crm_get_peer(id, uname);
    }
    return node;
}

crm_node_t *
pcmk__search_cluster_node_cache(unsigned int id, const char *uname)
{
    GHashTableIter iter;
    crm_node_t *node = NULL;
    crm_node_t *by_id = NULL;
    crm_node_t *by_name = NULL;

    CRM_ASSERT(id > 0 || uname != NULL);

    crm_peer_init();

    if (uname != NULL) {
        g_hash_table_iter_init(&iter, crm_peer_cache);
        while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &node)) {
            if(node->uname && strcasecmp(node->uname, uname) == 0) {
                crm_trace("Name match: %s = %p", node->uname, node);
                by_name = node;
                break;
            }
        }
    }

    if (id > 0) {
        g_hash_table_iter_init(&iter, crm_peer_cache);
        while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &node)) {
            if(node->id == id) {
                crm_trace("ID match: %u = %p", node->id, node);
                by_id = node;
                break;
            }
        }
    }

    node = by_id; /* Good default */
    if(by_id == by_name) {
        /* Nothing to do if they match (both NULL counts) */
        crm_trace("Consistent: %p for %u/%s", by_id, id, uname);

    } else if(by_id == NULL && by_name) {
        crm_trace("Only one: %p for %u/%s", by_name, id, uname);

        if(id && by_name->id) {
            dump_peer_hash(LOG_WARNING, __func__);
            crm_crit("Node %u and %u share the same name '%s'",
                     id, by_name->id, uname);
            node = NULL; /* Create a new one */

        } else {
            node = by_name;
        }

    } else if(by_name == NULL && by_id) {
        crm_trace("Only one: %p for %u/%s", by_id, id, uname);

        if(uname && by_id->uname) {
            dump_peer_hash(LOG_WARNING, __func__);
            crm_crit("Node '%s' and '%s' share the same cluster nodeid %u: assuming '%s' is correct",
                     uname, by_id->uname, id, uname);
        }

    } else if(uname && by_id->uname) {
        if(pcmk__str_eq(uname, by_id->uname, pcmk__str_casei)) {
            crm_notice("Node '%s' has changed its ID from %u to %u", by_id->uname, by_name->id, by_id->id);
            g_hash_table_foreach_remove(crm_peer_cache, hash_find_by_data, by_name);

        } else {
            crm_warn("Node '%s' and '%s' share the same cluster nodeid: %u %s", by_id->uname, by_name->uname, id, uname);
            dump_peer_hash(LOG_INFO, __func__);
            crm_abort(__FILE__, __func__, __LINE__, "member weirdness", TRUE,
                      TRUE);
        }

    } else if(id && by_name->id) {
        crm_warn("Node %u and %u share the same name: '%s'", by_id->id, by_name->id, uname);

    } else {
        /* Simple merge */

        /* Only corosync-based clusters use node IDs. The functions that call
         * pcmk__update_peer_state() and crm_update_peer_proc() only know
         * nodeid, so 'by_id' is authoritative when merging.
         */
        dump_peer_hash(LOG_DEBUG, __func__);

        crm_info("Merging %p into %p", by_name, by_id);
        g_hash_table_foreach_remove(crm_peer_cache, hash_find_by_data, by_name);
    }

    return node;
}

#if SUPPORT_COROSYNC
static guint
remove_conflicting_peer(crm_node_t *node)
{
    int matches = 0;
    GHashTableIter iter;
    crm_node_t *existing_node = NULL;

    if (node->id == 0 || node->uname == NULL) {
        return 0;
    }

    if (!pcmk__corosync_has_nodelist()) {
        return 0;
    }

    g_hash_table_iter_init(&iter, crm_peer_cache);
    while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &existing_node)) {
        if (existing_node->id > 0
            && existing_node->id != node->id
            && existing_node->uname != NULL
            && strcasecmp(existing_node->uname, node->uname) == 0) {

            if (crm_is_peer_active(existing_node)) {
                continue;
            }

            crm_warn("Removing cached offline node %u/%s which has conflicting uname with %u",
                     existing_node->id, existing_node->uname, node->id);

            g_hash_table_iter_remove(&iter);
            matches++;
        }
    }

    return matches;
}
#endif

/* coverity[-alloc] Memory is referenced in one or both hashtables */
crm_node_t *
crm_get_peer(unsigned int id, const char *uname)
{
    crm_node_t *node = NULL;
    char *uname_lookup = NULL;

    CRM_ASSERT(id > 0 || uname != NULL);

    crm_peer_init();

    node = pcmk__search_cluster_node_cache(id, uname);

    /* if uname wasn't provided, and find_peer did not turn up a uname based on id.
     * we need to do a lookup of the node name using the id in the cluster membership. */
    if ((node == NULL || node->uname == NULL) && (uname == NULL)) { 
        uname_lookup = get_node_name(id);
    }

    if (uname_lookup) {
        uname = uname_lookup;
        crm_trace("Inferred a name of '%s' for node %u", uname, id);

        /* try to turn up the node one more time now that we know the uname. */
        if (node == NULL) {
            node = pcmk__search_cluster_node_cache(id, uname);
        }
    }


    if (node == NULL) {
        char *uniqueid = crm_generate_uuid();

        node = calloc(1, sizeof(crm_node_t));
        CRM_ASSERT(node);

        crm_info("Created entry %s/%p for node %s/%u (%d total)",
                 uniqueid, node, uname, id, 1 + g_hash_table_size(crm_peer_cache));
        g_hash_table_replace(crm_peer_cache, uniqueid, node);
    }

    if(id > 0 && uname && (node->id == 0 || node->uname == NULL)) {
        crm_info("Node %u is now known as %s", id, uname);
    }

    if(id > 0 && node->id == 0) {
        node->id = id;
    }

    if (uname && (node->uname == NULL)) {
        update_peer_uname(node, uname);
    }

    if(node->uuid == NULL) {
        const char *uuid = crm_peer_uuid(node);

        if (uuid) {
            crm_info("Node %u has uuid %s", id, uuid);

        } else {
            crm_info("Cannot obtain a UUID for node %u/%s", id, node->uname);
        }
    }

    free(uname_lookup);

    return node;
}

static void
update_peer_uname(crm_node_t *node, const char *uname)
{
    CRM_CHECK(uname != NULL,
              crm_err("Bug: can't update node name without name"); return);
    CRM_CHECK(node != NULL,
              crm_err("Bug: can't update node name to %s without node", uname);
              return);

    if (pcmk__str_eq(uname, node->uname, pcmk__str_casei)) {
        crm_debug("Node uname '%s' did not change", uname);
        return;
    }

    for (const char *c = uname; *c; ++c) {
        if ((*c >= 'A') && (*c <= 'Z')) {
            crm_warn("Node names with capitals are discouraged, consider changing '%s'",
                     uname);
            break;
        }
    }

    free(node->uname);
    node->uname = strdup(uname);
    CRM_ASSERT(node->uname != NULL);

    if (peer_status_callback != NULL) {
        peer_status_callback(crm_status_uname, node, NULL);
    }

#if SUPPORT_COROSYNC
    if (is_corosync_cluster() && !pcmk_is_set(node->flags, crm_remote_node)) {
        remove_conflicting_peer(node);
    }
#endif
}

static inline const char *
proc2text(enum crm_proc_flag proc)
{
    const char *text = "unknown";

    switch (proc) {
        case crm_proc_none:
            text = "none";
            break;
        case crm_proc_based:
            text = "pacemaker-based";
            break;
        case crm_proc_controld:
            text = "pacemaker-controld";
            break;
        case crm_proc_schedulerd:
            text = "pacemaker-schedulerd";
            break;
        case crm_proc_execd:
            text = "pacemaker-execd";
            break;
        case crm_proc_attrd:
            text = "pacemaker-attrd";
            break;
        case crm_proc_fenced:
            text = "pacemaker-fenced";
            break;
        case crm_proc_cpg:
            text = "corosync-cpg";
            break;
    }
    return text;
}

crm_node_t *
crm_update_peer_proc(const char *source, crm_node_t * node, uint32_t flag, const char *status)
{
    uint32_t last = 0;
    gboolean changed = FALSE;

    CRM_CHECK(node != NULL, crm_err("%s: Could not set %s to %s for NULL",
                                    source, proc2text(flag), status);
                            return NULL);

    /* Pacemaker doesn't spawn processes on remote nodes */
    if (pcmk_is_set(node->flags, crm_remote_node)) {
        return node;
    }

    last = node->processes;
    if (status == NULL) {
        node->processes = flag;
        if (node->processes != last) {
            changed = TRUE;
        }

    } else if (pcmk__str_eq(status, ONLINESTATUS, pcmk__str_casei)) {
        if ((node->processes & flag) != flag) {
            node->processes = pcmk__set_flags_as(__func__, __LINE__,
                                                 LOG_TRACE, "Peer process",
                                                 node->uname, node->processes,
                                                 flag, "processes");
            changed = TRUE;
        }

    } else if (node->processes & flag) {
        node->processes = pcmk__clear_flags_as(__func__, __LINE__,
                                               LOG_TRACE, "Peer process",
                                               node->uname, node->processes,
                                               flag, "processes");
        changed = TRUE;
    }

    if (changed) {
        if (status == NULL && flag <= crm_proc_none) {
            crm_info("%s: Node %s[%u] - all processes are now offline", source, node->uname,
                     node->id);
        } else {
            crm_info("%s: Node %s[%u] - %s is now %s", source, node->uname, node->id,
                     proc2text(flag), status);
        }

        /* Call the client callback first, then update the peer state,
         * in case the node will be reaped
         */
        if (peer_status_callback != NULL) {
            peer_status_callback(crm_status_processes, node, &last);
        }

        /* The client callback shouldn't touch the peer caches,
         * but as a safety net, bail if the peer cache was destroyed.
         */
        if (crm_peer_cache == NULL) {
            return NULL;
        }

        if (crm_autoreap) {
            const char *peer_state = NULL;

            if (pcmk_is_set(node->processes, crm_get_cluster_proc())) {
                peer_state = CRM_NODE_MEMBER;
            } else {
                peer_state = CRM_NODE_LOST;
            }
            node = pcmk__update_peer_state(__func__, node, peer_state, 0);
        }
    } else {
        crm_trace("%s: Node %s[%u] - %s is unchanged (%s)", source, node->uname, node->id,
                  proc2text(flag), status);
    }
    return node;
}

void
pcmk__update_peer_expected(const char *source, crm_node_t *node,
                           const char *expected)
{
    char *last = NULL;
    gboolean changed = FALSE;

    CRM_CHECK(node != NULL, crm_err("%s: Could not set 'expected' to %s", source, expected);
              return);

    /* Remote nodes don't participate in joins */
    if (pcmk_is_set(node->flags, crm_remote_node)) {
        return;
    }

    last = node->expected;
    if (expected != NULL && !pcmk__str_eq(node->expected, expected, pcmk__str_casei)) {
        node->expected = strdup(expected);
        changed = TRUE;
    }

    if (changed) {
        crm_info("%s: Node %s[%u] - expected state is now %s (was %s)", source, node->uname, node->id,
                 expected, last);
        free(last);
    } else {
        crm_trace("%s: Node %s[%u] - expected state is unchanged (%s)", source, node->uname,
                  node->id, expected);
    }
}

static crm_node_t *
update_peer_state_iter(const char *source, crm_node_t *node, const char *state,
                       uint64_t membership, GHashTableIter *iter)
{
    gboolean is_member;

    CRM_CHECK(node != NULL,
              crm_err("Could not set state for unknown host to %s"
                      CRM_XS " source=%s", state, source);
              return NULL);

    is_member = pcmk__str_eq(state, CRM_NODE_MEMBER, pcmk__str_casei);
    if (is_member) {
        node->when_lost = 0;
        if (membership) {
            node->last_seen = membership;
        }
    }

    if (state && !pcmk__str_eq(node->state, state, pcmk__str_casei)) {
        char *last = node->state;

        node->state = strdup(state);
        crm_notice("Node %s state is now %s " CRM_XS
                   " nodeid=%u previous=%s source=%s", node->uname, state,
                   node->id, (last? last : "unknown"), source);
        if (peer_status_callback != NULL) {
            peer_status_callback(crm_status_nstate, node, last);
        }
        free(last);

        if (crm_autoreap && !is_member
            && !pcmk_is_set(node->flags, crm_remote_node)) {
            /* We only autoreap from the peer cache, not the remote peer cache,
             * because the latter should be managed only by
             * crm_remote_peer_cache_refresh().
             */
            if(iter) {
                crm_notice("Purged 1 peer with id=%u and/or uname=%s from the membership cache", node->id, node->uname);
                g_hash_table_iter_remove(iter);

            } else {
                reap_crm_member(node->id, node->uname);
            }
            node = NULL;
        }

    } else {
        crm_trace("Node %s state is unchanged (%s) " CRM_XS
                  " nodeid=%u source=%s", node->uname, state, node->id, source);
    }
    return node;
}

crm_node_t *
pcmk__update_peer_state(const char *source, crm_node_t *node,
                        const char *state, uint64_t membership)
{
    return update_peer_state_iter(source, node, state, membership, NULL);
}

void
pcmk__reap_unseen_nodes(uint64_t membership)
{
    GHashTableIter iter;
    crm_node_t *node = NULL;

    crm_trace("Reaping unseen nodes...");
    g_hash_table_iter_init(&iter, crm_peer_cache);
    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&node)) {
        if (node->last_seen != membership) {
            if (node->state) {
                /*
                 * Calling update_peer_state_iter() allows us to
                 * remove the node from crm_peer_cache without
                 * invalidating our iterator
                 */
                update_peer_state_iter(__func__, node, CRM_NODE_LOST,
                                           membership, &iter);

            } else {
                crm_info("State of node %s[%u] is still unknown",
                         node->uname, node->id);
            }
        }
    }
}

static crm_node_t *
find_known_node(const char *id, const char *uname)
{
    GHashTableIter iter;
    crm_node_t *node = NULL;
    crm_node_t *by_id = NULL;
    crm_node_t *by_name = NULL;

    if (uname) {
        g_hash_table_iter_init(&iter, known_node_cache);
        while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &node)) {
            if (node->uname && strcasecmp(node->uname, uname) == 0) {
                crm_trace("Name match: %s = %p", node->uname, node);
                by_name = node;
                break;
            }
        }
    }

    if (id) {
        g_hash_table_iter_init(&iter, known_node_cache);
        while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &node)) {
            if(strcasecmp(node->uuid, id) == 0) {
                crm_trace("ID match: %s= %p", id, node);
                by_id = node;
                break;
            }
        }
    }

    node = by_id; /* Good default */
    if (by_id == by_name) {
        /* Nothing to do if they match (both NULL counts) */
        crm_trace("Consistent: %p for %s/%s", by_id, id, uname);

    } else if (by_id == NULL && by_name) {
        crm_trace("Only one: %p for %s/%s", by_name, id, uname);

        if (id) {
            node = NULL;

        } else {
            node = by_name;
        }

    } else if (by_name == NULL && by_id) {
        crm_trace("Only one: %p for %s/%s", by_id, id, uname);

        if (uname) {
            node = NULL;
        }

    } else if (uname && by_id->uname
               && pcmk__str_eq(uname, by_id->uname, pcmk__str_casei)) {
        /* Multiple nodes have the same uname in the CIB.
         * Return by_id. */

    } else if (id && by_name->uuid
               && pcmk__str_eq(id, by_name->uuid, pcmk__str_casei)) {
        /* Multiple nodes have the same id in the CIB.
         * Return by_name. */
        node = by_name;

    } else {
        node = NULL;
    }

    if (node == NULL) {
        crm_debug("Couldn't find node%s%s%s%s",
                   id? " " : "",
                   id? id : "",
                   uname? " with name " : "",
                   uname? uname : "");
    }

    return node;
}

static void
known_node_cache_refresh_helper(xmlNode *xml_node, void *user_data)
{
    const char *id = crm_element_value(xml_node, XML_ATTR_ID);
    const char *uname = crm_element_value(xml_node, XML_ATTR_UNAME);
    crm_node_t * node =  NULL;

    CRM_CHECK(id != NULL && uname !=NULL, return);
    node = find_known_node(id, uname);

    if (node == NULL) {
        char *uniqueid = crm_generate_uuid();

        node = calloc(1, sizeof(crm_node_t));
        CRM_ASSERT(node != NULL);

        node->uname = strdup(uname);
        CRM_ASSERT(node->uname != NULL);

        node->uuid = strdup(id);
        CRM_ASSERT(node->uuid != NULL);

        g_hash_table_replace(known_node_cache, uniqueid, node);

    } else if (pcmk_is_set(node->flags, crm_node_dirty)) {
        if (!pcmk__str_eq(uname, node->uname, pcmk__str_casei)) {
            free(node->uname);
            node->uname = strdup(uname);
            CRM_ASSERT(node->uname != NULL);
        }

        /* Node is in cache and hasn't been updated already, so mark it clean */
        clear_peer_flags(node, crm_node_dirty);
    }

}

static void
refresh_known_node_cache(xmlNode *cib)
{
    crm_peer_init();

    g_hash_table_foreach(known_node_cache, mark_dirty, NULL);

    crm_foreach_xpath_result(cib, PCMK__XP_MEMBER_NODE_CONFIG,
                             known_node_cache_refresh_helper, NULL);

    /* Remove all old cache entries that weren't seen in the CIB */
    g_hash_table_foreach_remove(known_node_cache, is_dirty, NULL);
}

void
pcmk__refresh_node_caches_from_cib(xmlNode *cib)
{
    crm_remote_peer_cache_refresh(cib);
    refresh_known_node_cache(cib);
}

crm_node_t *
pcmk__search_known_node_cache(unsigned int id, const char *uname,
                              uint32_t flags)
{
    crm_node_t *node = NULL;
    char *id_str = NULL;

    CRM_ASSERT(id > 0 || uname != NULL);

    node = pcmk__search_node_caches(id, uname, flags);

    if (node || !(flags & CRM_GET_PEER_CLUSTER)) {
        return node;
    }

    if (id > 0) {
        id_str = crm_strdup_printf("%u", id);
    }

    node = find_known_node(id_str, uname);

    free(id_str);
    return node;
}


// Deprecated functions kept only for backward API compatibility
// LCOV_EXCL_START

#include <crm/cluster/compat.h>

int
crm_terminate_member(int nodeid, const char *uname, void *unused)
{
    return stonith_api_kick(nodeid, uname, 120, TRUE);
}

int
crm_terminate_member_no_mainloop(int nodeid, const char *uname, int *connection)
{
    return stonith_api_kick(nodeid, uname, 120, TRUE);
}

// LCOV_EXCL_STOP
// End deprecated API