vsf_quorum.c

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/*
 * Copyright (c) 2008-2020 Red Hat, Inc.
 *
 * All rights reserved.
 *
 * Author: Christine Caulfield (ccaulfie@redhat.com)
 *
 * This software licensed under BSD license, the text of which follows:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of Red Hat Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <config.h>
 
#include <pwd.h>
#include <grp.h>
#include <sys/types.h>
#include <sys/poll.h>
#include <sys/uio.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <sched.h>
#include <time.h>
 
#include "quorum.h"
#include <corosync/corotypes.h>
#include <qb/qbipc_common.h>
#include <corosync/corodefs.h>
#include <corosync/swab.h>
#include <qb/qblist.h>
#include <corosync/mar_gen.h>
#include <corosync/ipc_quorum.h>
#include <corosync/coroapi.h>
#include <corosync/logsys.h>
#include <corosync/icmap.h>
 
#include "service.h"
#include "votequorum.h"
#include "vsf_ykd.h"
 
LOGSYS_DECLARE_SUBSYS ("QUORUM");
 
struct quorum_pd {
        unsigned char track_flags;
        int tracking_enabled;
        struct qb_list_head list;
        void *conn;
        enum lib_quorum_model model;
};
 
struct internal_callback_pd {
        struct qb_list_head list;
        quorum_callback_fn_t callback;
        void *context;
};
 
static void quorum_sync_init (
        const unsigned int *trans_list,
        size_t trans_list_entries,
        const unsigned int *member_list,
        size_t member_list_entries,
        const struct memb_ring_id *ring_id);
 
static int quorum_sync_process (void);
 
static void quorum_sync_activate (void);
 
static void quorum_sync_abort (void);
 
static void message_handler_req_lib_quorum_getquorate (void *conn,
                                                       const void *msg);
static void message_handler_req_lib_quorum_trackstart (void *conn,
                                                       const void *msg);
static void message_handler_req_lib_quorum_trackstop (void *conn,
                                                      const void *msg);
static void message_handler_req_lib_quorum_gettype (void *conn,
                                                       const void *msg);
static void message_handler_req_lib_quorum_model_gettype (void *conn,
                                                       const void *msg);
static void send_library_notification(void *conn);
static void send_internal_notification(void);
static void send_nodelist_library_notification(void *conn, int send_joined_left_list);
static char *quorum_exec_init_fn (struct corosync_api_v1 *api);
static int quorum_lib_init_fn (void *conn);
static int quorum_lib_exit_fn (void *conn);
 
static int primary_designated = 0;
static int quorum_type = 0;
static struct corosync_api_v1 *corosync_api;
static struct qb_list_head lib_trackers_list;
static struct qb_list_head internal_trackers_list;
static struct memb_ring_id quorum_ring_id;
static struct memb_ring_id last_sync_ring_id;
static size_t quorum_view_list_entries = 0;
static int quorum_view_list[PROCESSOR_COUNT_MAX];
struct quorum_services_api_ver1 *quorum_iface = NULL;
 
static char view_buf[64];
 
static unsigned int my_member_list[PROCESSOR_COUNT_MAX];
static size_t my_member_list_entries;
static unsigned int my_old_member_list[PROCESSOR_COUNT_MAX];
static size_t my_old_member_list_entries = 0;
static unsigned int my_left_list[PROCESSOR_COUNT_MAX];
static size_t my_left_list_entries;
static unsigned int my_joined_list[PROCESSOR_COUNT_MAX];
static size_t my_joined_list_entries;
 
static void log_view_list(const unsigned int *view_list, size_t view_list_entries,
    const char *view_list_type_str)
{
        int total = (int)view_list_entries;
        int len, pos, ret;
        int i = 0;
 
        while (1) {
                len = sizeof(view_buf);
                pos = 0;
                memset(view_buf, 0, len);
 
                for (; i < total; i++) {
                        ret = snprintf(view_buf + pos, len - pos, " " CS_PRI_NODE_ID, view_list[i]);
                        if (ret >= len - pos)
                                break;
                        pos += ret;
                }
                log_printf (LOGSYS_LEVEL_NOTICE, "%s[%d]:%s%s",
                            view_list_type_str, total, view_buf, i < total ? "\\" : "");
 
                if (i == total)
                        break;
        }
}
 
/* Internal quorum API function */
static void quorum_api_set_quorum(const unsigned int *view_list,
                                  size_t view_list_entries,
                                  int quorum, struct memb_ring_id *ring_id)
{
        int old_quorum = primary_designated;
        primary_designated = quorum;
 
        if (primary_designated && !old_quorum) {
                log_printf (LOGSYS_LEVEL_NOTICE, "This node is within the primary component and will provide service.");
        } else if (!primary_designated && old_quorum) {
                log_printf (LOGSYS_LEVEL_NOTICE, "This node is within the non-primary component and will NOT provide any services.");
        }
 
        quorum_view_list_entries = view_list_entries;
        memcpy(&quorum_ring_id, ring_id, sizeof (quorum_ring_id));
        memcpy(quorum_view_list, view_list, sizeof(unsigned int)*view_list_entries);
 
        log_view_list(view_list, view_list_entries, "Members");
 
        /* Tell internal listeners */
        send_internal_notification();
 
        /* Tell IPC listeners */
        send_library_notification(NULL);
}
 
static struct corosync_lib_handler quorum_lib_service[] =
{
        { /* 0 */
                .lib_handler_fn                         = message_handler_req_lib_quorum_getquorate,
                .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED
        },
        { /* 1 */
                .lib_handler_fn                         = message_handler_req_lib_quorum_trackstart,
                .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED
        },
        { /* 2 */
                .lib_handler_fn                         = message_handler_req_lib_quorum_trackstop,
                .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED
        },
        { /* 3 */
                .lib_handler_fn                         = message_handler_req_lib_quorum_gettype,
                .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED
        },
        { /* 4 */
                .lib_handler_fn                         = message_handler_req_lib_quorum_model_gettype,
                .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED
        }
};
 
static struct corosync_service_engine quorum_service_handler = {
        .name                                   = "corosync cluster quorum service v0.1",
        .id                                     = QUORUM_SERVICE,
        .priority                               = 1,
        .private_data_size                      = sizeof (struct quorum_pd),
        .flow_control                           = CS_LIB_FLOW_CONTROL_NOT_REQUIRED,
        .allow_inquorate                        = CS_LIB_ALLOW_INQUORATE,
        .lib_init_fn                            = quorum_lib_init_fn,
        .lib_exit_fn                            = quorum_lib_exit_fn,
        .lib_engine                             = quorum_lib_service,
        .exec_init_fn                           = quorum_exec_init_fn,
        .sync_init                              = quorum_sync_init,
        .sync_process                           = quorum_sync_process,
        .sync_activate                          = quorum_sync_activate,
        .sync_abort                             = quorum_sync_abort,
        .lib_engine_count                       = sizeof (quorum_lib_service) / sizeof (struct corosync_lib_handler)
};
 
struct corosync_service_engine *vsf_quorum_get_service_engine_ver0 (void)
{
        return (&quorum_service_handler);
}
 
/* -------------------------------------------------- */
 
 
/*
 * Internal API functions for corosync
 */
 
static int quorum_quorate(void)
{
        return primary_designated;
}
 
 
static int quorum_register_callback(quorum_callback_fn_t function, void *context)
{
        struct internal_callback_pd *pd = malloc(sizeof(struct internal_callback_pd));
        if (!pd)
                return -1;
 
        pd->context  = context;
        pd->callback = function;
        qb_list_add (&pd->list, &internal_trackers_list);
 
        return 0;
}
 
static int quorum_unregister_callback(quorum_callback_fn_t function, void *context)
{
        struct internal_callback_pd *pd;
        struct qb_list_head *tmp, *tmp_iter;
 
        qb_list_for_each_safe(tmp, tmp_iter, &internal_trackers_list) {
                pd = qb_list_entry(tmp, struct internal_callback_pd, list);
                if (pd->callback == function && pd->context == context) {
                        qb_list_del(&pd->list);
                        free(pd);
                        return 0;
                }
        }
        return -1;
}
 
static struct quorum_callin_functions callins = {
        .quorate = quorum_quorate,
        .register_callback = quorum_register_callback,
        .unregister_callback = quorum_unregister_callback
};
 
/* --------------------------------------------------------------------- */
 
static void quorum_sync_init (
        const unsigned int *trans_list,
        size_t trans_list_entries,
        const unsigned int *member_list,
        size_t member_list_entries,
        const struct memb_ring_id *ring_id)
{
        int found;
        int i, j;
        int entries;
        int node_joined;
 
        memcpy (my_member_list, member_list, member_list_entries *
            sizeof (unsigned int));
        my_member_list_entries = member_list_entries;
 
        last_sync_ring_id = *ring_id;
 
        /*
         * Determine left list of nodeids
         */
        entries = 0;
        for (i = 0; i < my_old_member_list_entries; i++) {
                found = 0;
                for (j = 0; j < trans_list_entries; j++) {
                        if (my_old_member_list[i] == trans_list[j]) {
                                found = 1;
                                break;
                        }
                }
 
                if (found == 0) {
                        my_left_list[entries++] = my_old_member_list[i];
                } else {
                        /*
                         * Check it is really in new membership
                         */
                        found = 0;
 
                        for (j = 0; j < my_member_list_entries; j++) {
                                if (my_old_member_list[i] == my_member_list[j]) {
                                        found = 1;
                                        break;
                                }
                        }
 
                        /*
                         * Node is in both old_member_list and trans list but not in my_member_list.
                         * (This shouldn't really happen).
                         */
                        if (!found) {
                                my_left_list[entries++] = my_old_member_list[i];
                        }
                }
        }
        my_left_list_entries = entries;
 
        /*
         * Determine joined list of nodeids
         */
        entries = 0;
        for (i = 0; i < my_member_list_entries; i++) {
                node_joined = 1;
                for (j = 0; j < my_old_member_list_entries; j++) {
                        if (my_member_list[i] == my_old_member_list[j]) {
                                /*
                                 * Node is in member list and also in my_old_member list -> check
                                 * if it is in left_list.
                                 */
                                node_joined = 0;
                                break;
                        }
                }
 
                if (!node_joined) {
                        /*
                         * Check if node is in left list.
                         */
                        for (j = 0; j < my_left_list_entries; j++) {
                                if (my_member_list[i] == my_left_list[j]) {
                                        /*
                                         * Node is both in left and also in member list -> joined
                                         */
                                        node_joined = 1;
                                        break;
                                }
                        }
                }
 
                if (node_joined) {
                        my_joined_list[entries++] = my_member_list[i];
                }
        }
        my_joined_list_entries = entries;
 
        log_view_list(my_member_list, my_member_list_entries, "Sync members");
 
        if (my_joined_list_entries > 0) {
                log_view_list(my_joined_list, my_joined_list_entries, "Sync joined");
        }
 
        if (my_left_list_entries > 0) {
                log_view_list(my_left_list, my_left_list_entries, "Sync left");
        }
}
 
static int quorum_sync_process (void)
{
 
        return (0);
}
 
static void quorum_sync_activate (void)
{
 
        memcpy (my_old_member_list, my_member_list,
            my_member_list_entries * sizeof (unsigned int));
        my_old_member_list_entries = my_member_list_entries;
 
        /* Tell IPC listeners */
        send_nodelist_library_notification(NULL, 1);
}
 
static void quorum_sync_abort (void)
{
 
}
 
static char *quorum_exec_init_fn (struct corosync_api_v1 *api)
{
        char *quorum_module = NULL;
        char *error;
 
        corosync_api = api;
        qb_list_init (&lib_trackers_list);
        qb_list_init (&internal_trackers_list);
 
        /*
         * Tell corosync we have a quorum engine.
         */
        api->quorum_initialize(&callins);
 
        /*
         * Look for a quorum provider
         */
        if (icmap_get_string("quorum.provider", &quorum_module) == CS_OK) {
                log_printf (LOGSYS_LEVEL_NOTICE,
                            "Using quorum provider %s", quorum_module);
 
                error = (char *)"Invalid quorum provider";
 
                if (strcmp (quorum_module, "corosync_votequorum") == 0) {
                        error = votequorum_init (api, quorum_api_set_quorum);
                        quorum_type = 1;
                }
                if (strcmp (quorum_module, "corosync_ykd") == 0) {
                        error = ykd_init (api, quorum_api_set_quorum);
                        quorum_type = 1;
                }
                if (error) {
                        log_printf (LOGSYS_LEVEL_CRIT, 
                                "Quorum provider: %s failed to initialize.",
                                 quorum_module);
                        free(quorum_module);
                        return (error);
                }
        }
 
        if (quorum_module) {
                free(quorum_module);
                quorum_module = NULL;
        }
 
        /*
         * setting quorum_type and primary_designated in the right order is important
         * always try to lookup/init a quorum module, then revert back to be quorate
         */
 
        if (quorum_type == 0) {
                primary_designated = 1;
        }
 
        return (NULL);
}
 
static int quorum_lib_init_fn (void *conn)
{
        struct quorum_pd *pd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
 
        log_printf(LOGSYS_LEVEL_DEBUG, "lib_init_fn: conn=%p", conn);
 
        qb_list_init (&pd->list);
        pd->conn = conn;
        pd->model = LIB_QUORUM_MODEL_V0;
 
        return (0);
}
 
static int quorum_lib_exit_fn (void *conn)
{
        struct quorum_pd *quorum_pd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
 
        log_printf(LOGSYS_LEVEL_DEBUG, "lib_exit_fn: conn=%p", conn);
 
        if (quorum_pd->tracking_enabled) {
                qb_list_del (&quorum_pd->list);
                qb_list_init (&quorum_pd->list);
        }
        return (0);
}
 
 
static void send_internal_notification(void)
{
        struct qb_list_head *tmp;
        struct internal_callback_pd *pd;
 
        qb_list_for_each(tmp, &internal_trackers_list) {
                pd = qb_list_entry(tmp, struct internal_callback_pd, list);
 
                pd->callback(primary_designated, pd->context);
        }
}
 
static void prepare_library_notification_v0(char *buf, size_t size)
{
        struct res_lib_quorum_notification *res_lib_quorum_notification = (struct res_lib_quorum_notification *)buf;
        int i;
 
        res_lib_quorum_notification->quorate = primary_designated;
        res_lib_quorum_notification->ring_seq = quorum_ring_id.seq;
        res_lib_quorum_notification->view_list_entries = quorum_view_list_entries;
        for (i=0; i<quorum_view_list_entries; i++) {
                res_lib_quorum_notification->view_list[i] = quorum_view_list[i];
        }
 
        res_lib_quorum_notification->header.id = MESSAGE_RES_QUORUM_NOTIFICATION;
        res_lib_quorum_notification->header.size = size;
        res_lib_quorum_notification->header.error = CS_OK;
}
 
static void prepare_library_notification_v1(char *buf, size_t size)
{
        struct res_lib_quorum_v1_quorum_notification *res_lib_quorum_v1_quorum_notification =
            (struct res_lib_quorum_v1_quorum_notification *)buf;
        int i;
 
        res_lib_quorum_v1_quorum_notification->quorate = primary_designated;
        res_lib_quorum_v1_quorum_notification->ring_id.nodeid = quorum_ring_id.nodeid;
        res_lib_quorum_v1_quorum_notification->ring_id.seq = quorum_ring_id.seq;
        res_lib_quorum_v1_quorum_notification->view_list_entries = quorum_view_list_entries;
        for (i=0; i<quorum_view_list_entries; i++) {
                res_lib_quorum_v1_quorum_notification->view_list[i] = quorum_view_list[i];
        }
 
        res_lib_quorum_v1_quorum_notification->header.id = MESSAGE_RES_QUORUM_V1_QUORUM_NOTIFICATION;
        res_lib_quorum_v1_quorum_notification->header.size = size;
        res_lib_quorum_v1_quorum_notification->header.error = CS_OK;
}
 
static void send_library_notification(void *conn)
{
        int size_v0 = sizeof(struct res_lib_quorum_notification) +
            sizeof(mar_uint32_t) * quorum_view_list_entries;
        int size_v1 = sizeof(struct res_lib_quorum_v1_quorum_notification) +
            sizeof(mar_uint32_t)*quorum_view_list_entries;
 
        char buf_v0[size_v0];
        char buf_v1[size_v1];
 
        struct res_lib_quorum_notification *res_lib_quorum_notification =
            (struct res_lib_quorum_notification *)buf_v0;
        struct res_lib_quorum_v1_quorum_notification *res_lib_quorum_v1_quorum_notification =
            (struct res_lib_quorum_v1_quorum_notification *)buf_v1;
 
        struct quorum_pd *qpd;
        struct qb_list_head *tmp;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "sending quorum notification to %p, length = %u/%u", conn, size_v0, size_v1);
 
        prepare_library_notification_v0(buf_v0, size_v0);
        prepare_library_notification_v1(buf_v1, size_v1);
 
        /* Send it to all interested parties */
        if (conn) {
                qpd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
 
                if (qpd->model == LIB_QUORUM_MODEL_V0) {
                        corosync_api->ipc_dispatch_send(conn, res_lib_quorum_notification, size_v0);
                } else if (qpd->model == LIB_QUORUM_MODEL_V1) {
                        corosync_api->ipc_dispatch_send(conn, res_lib_quorum_v1_quorum_notification, size_v1);
                }
        }
        else {
                qb_list_for_each(tmp, &lib_trackers_list) {
                        qpd = qb_list_entry(tmp, struct quorum_pd, list);
 
                        if (qpd->model == LIB_QUORUM_MODEL_V0) {
                                corosync_api->ipc_dispatch_send(qpd->conn,
                                     res_lib_quorum_notification, size_v0);
                        } else if (qpd->model == LIB_QUORUM_MODEL_V1) {
                                corosync_api->ipc_dispatch_send(qpd->conn,
                                     res_lib_quorum_v1_quorum_notification, size_v1);
                        }
                }
        }
        return;
}
 
static void send_nodelist_library_notification(void *conn, int send_joined_left_list)
{
        int size = sizeof(struct res_lib_quorum_v1_nodelist_notification) +
            sizeof(mar_uint32_t) * my_member_list_entries;
        char *buf;
        struct res_lib_quorum_v1_nodelist_notification *res_lib_quorum_v1_nodelist_notification;
        struct quorum_pd *qpd;
        struct qb_list_head *tmp;
        mar_uint32_t *ptr;
        int i;
 
        if (send_joined_left_list) {
                size += sizeof(mar_uint32_t) * my_joined_list_entries;
                size += sizeof(mar_uint32_t) * my_left_list_entries;
        }
 
        buf = alloca(size);
        memset(buf, 0, size);
 
        res_lib_quorum_v1_nodelist_notification = (struct res_lib_quorum_v1_nodelist_notification *)buf;
 
        res_lib_quorum_v1_nodelist_notification->ring_id.nodeid = last_sync_ring_id.nodeid;
        res_lib_quorum_v1_nodelist_notification->ring_id.seq = last_sync_ring_id.seq;
        res_lib_quorum_v1_nodelist_notification->member_list_entries = my_member_list_entries;
 
        if (send_joined_left_list) {
                res_lib_quorum_v1_nodelist_notification->joined_list_entries = my_joined_list_entries;
                res_lib_quorum_v1_nodelist_notification->left_list_entries = my_left_list_entries;
        }
 
        ptr = res_lib_quorum_v1_nodelist_notification->member_list;
 
        for (i=0; i<my_member_list_entries; i++, ptr++) {
                *ptr = my_member_list[i];
        }
 
        if (send_joined_left_list) {
                for (i=0; i<my_joined_list_entries; i++, ptr++) {
                        *ptr = my_joined_list[i];
                }
 
                for (i=0; i<my_left_list_entries; i++, ptr++) {
                        *ptr = my_left_list[i];
                }
        }
 
        res_lib_quorum_v1_nodelist_notification->header.id = MESSAGE_RES_QUORUM_V1_NODELIST_NOTIFICATION;
        res_lib_quorum_v1_nodelist_notification->header.size = size;
        res_lib_quorum_v1_nodelist_notification->header.error = CS_OK;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "sending nodelist notification to %p, length = %u", conn, size);
 
        /* Send it to all interested parties */
        if (conn) {
                qpd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
 
                if (qpd->model == LIB_QUORUM_MODEL_V1) {
                        corosync_api->ipc_dispatch_send(conn, res_lib_quorum_v1_nodelist_notification, size);
                }
        }
        else {
                qb_list_for_each(tmp, &lib_trackers_list) {
                        qpd = qb_list_entry(tmp, struct quorum_pd, list);
 
                        if (qpd->model == LIB_QUORUM_MODEL_V1) {
                                corosync_api->ipc_dispatch_send(qpd->conn,
                                     res_lib_quorum_v1_nodelist_notification, size);
                        }
                }
        }
 
        return;
}
 
static void message_handler_req_lib_quorum_getquorate (void *conn,
                                                       const void *msg)
{
        struct res_lib_quorum_getquorate res_lib_quorum_getquorate;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "got quorate request on %p", conn);
 
        /* send status */
        res_lib_quorum_getquorate.quorate = primary_designated;
        res_lib_quorum_getquorate.header.size = sizeof(res_lib_quorum_getquorate);
        res_lib_quorum_getquorate.header.id = MESSAGE_RES_QUORUM_GETQUORATE;
        res_lib_quorum_getquorate.header.error = CS_OK;
        corosync_api->ipc_response_send(conn, &res_lib_quorum_getquorate, sizeof(res_lib_quorum_getquorate));
}
 
static void message_handler_req_lib_quorum_trackstart (void *conn,
                                                       const void *msg)
{
        const struct req_lib_quorum_trackstart *req_lib_quorum_trackstart = msg;
        struct qb_ipc_response_header res;
        struct quorum_pd *quorum_pd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
        cs_error_t error = CS_OK;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "got trackstart request on %p", conn);
 
        /*
         * If an immediate listing of the current cluster membership
         * is requested, generate membership list
         */
        if (req_lib_quorum_trackstart->track_flags & CS_TRACK_CURRENT ||
            req_lib_quorum_trackstart->track_flags & CS_TRACK_CHANGES) {
                log_printf(LOGSYS_LEVEL_DEBUG, "sending initial status to %p", conn);
                send_nodelist_library_notification(conn, 0);
                send_library_notification(conn);
        }
 
        if (quorum_pd->tracking_enabled) {
                error = CS_ERR_EXIST;
                goto response_send;
        }
 
        /*
         * Record requests for tracking
         */
        if (req_lib_quorum_trackstart->track_flags & CS_TRACK_CHANGES ||
            req_lib_quorum_trackstart->track_flags & CS_TRACK_CHANGES_ONLY) {
 
                quorum_pd->track_flags = req_lib_quorum_trackstart->track_flags;
                quorum_pd->tracking_enabled = 1;
 
                qb_list_add (&quorum_pd->list, &lib_trackers_list);
        }
 
response_send:
        /* send status */
        res.size = sizeof(res);
        res.id = MESSAGE_RES_QUORUM_TRACKSTART;
        res.error = error;
        corosync_api->ipc_response_send(conn, &res, sizeof(struct qb_ipc_response_header));
}
 
static void message_handler_req_lib_quorum_trackstop (void *conn, const void *msg)
{
        struct qb_ipc_response_header res;
        struct quorum_pd *quorum_pd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
 
        log_printf(LOGSYS_LEVEL_DEBUG, "got trackstop request on %p", conn);
 
        if (quorum_pd->tracking_enabled) {
                res.error = CS_OK;
                quorum_pd->tracking_enabled = 0;
                qb_list_del (&quorum_pd->list);
                qb_list_init (&quorum_pd->list);
        } else {
                res.error = CS_ERR_NOT_EXIST;
        }
 
        /* send status */
        res.size = sizeof(res);
        res.id = MESSAGE_RES_QUORUM_TRACKSTOP;
        res.error = CS_OK;
        corosync_api->ipc_response_send(conn, &res, sizeof(struct qb_ipc_response_header));
}
 
static void message_handler_req_lib_quorum_gettype (void *conn,
                                                       const void *msg)
{
        struct res_lib_quorum_gettype res_lib_quorum_gettype;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "got quorum_type request on %p", conn);
 
        /* send status */
        res_lib_quorum_gettype.quorum_type = quorum_type;
        res_lib_quorum_gettype.header.size = sizeof(res_lib_quorum_gettype);
        res_lib_quorum_gettype.header.id = MESSAGE_RES_QUORUM_GETTYPE;
        res_lib_quorum_gettype.header.error = CS_OK;
        corosync_api->ipc_response_send(conn, &res_lib_quorum_gettype, sizeof(res_lib_quorum_gettype));
}
 
static void message_handler_req_lib_quorum_model_gettype (void *conn,
                                                       const void *msg)
{
        const struct req_lib_quorum_model_gettype *req_lib_quorum_model_gettype = msg;
        struct res_lib_quorum_model_gettype res_lib_quorum_model_gettype;
        struct quorum_pd *quorum_pd = (struct quorum_pd *)corosync_api->ipc_private_data_get (conn);
        cs_error_t ret_err;
 
        log_printf(LOGSYS_LEVEL_DEBUG, "got quorum_model_type request on %p", conn);
 
        ret_err = CS_OK;
 
        if (req_lib_quorum_model_gettype->model != LIB_QUORUM_MODEL_V0 &&
            req_lib_quorum_model_gettype->model != LIB_QUORUM_MODEL_V1) {
                log_printf(LOGSYS_LEVEL_ERROR, "quorum_model_type request for unsupported model %u",
                    req_lib_quorum_model_gettype->model);
 
                ret_err = CS_ERR_INVALID_PARAM;
        } else {
                quorum_pd->model = req_lib_quorum_model_gettype->model;
        }
 
        /* send status */
        res_lib_quorum_model_gettype.quorum_type = quorum_type;
        res_lib_quorum_model_gettype.header.size = sizeof(res_lib_quorum_model_gettype);
        res_lib_quorum_model_gettype.header.id = MESSAGE_RES_QUORUM_MODEL_GETTYPE;
        res_lib_quorum_model_gettype.header.error = ret_err;
        corosync_api->ipc_response_send(conn, &res_lib_quorum_model_gettype, sizeof(res_lib_quorum_model_gettype));
}