389-ds-base/ldap/servers/plugins/replication/repl_connext.c

/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

/* repl_connext.c - replication extension to the Connection object
 */

#include "repl5.h"


/* ***** Supplier side ***** */

/* NOT NEEDED YET */

/* ***** Consumer side ***** */

/* consumer connection extension constructor */
void *
consumer_connection_extension_constructor(void *object __attribute__((unused)), void *parent __attribute__((unused)))
{
    consumer_connection_extension *ext = (consumer_connection_extension *)slapi_ch_malloc(sizeof(consumer_connection_extension));
    if (ext == NULL) {
        slapi_log_err(SLAPI_LOG_PLUGIN, repl_plugin_name, "consumer_connection_extension_constructor - "
                                                          "Unable to create replication consumer connection extension - out of memory\n");
    } else {
        ext->repl_protocol_version = REPL_PROTOCOL_UNKNOWN;
        ext->replica_acquired = NULL;
        ext->isreplicationsession = 0;
        ext->supplier_ruv = NULL;
        ext->connection = NULL;
        ext->in_use_opid = -1;
        ext->lock = PR_NewLock();
        if (NULL == ext->lock) {
            slapi_log_err(SLAPI_LOG_PLUGIN, repl_plugin_name, "consumer_connection_extension_constructor - "
                                                              "Unable to create replication consumer connection extension lock - out of memory\n");
            /* no need to go through the full destructor, but still need to free up this memory */
            slapi_ch_free((void **)&ext);
            ext = NULL;
        }
    }

    return ext;
}

/* consumer connection extension destructor */
void
consumer_connection_extension_destructor(void *ext, void *object __attribute__((unused)), void *parent __attribute__((unused)))
{
    PRUint64 connid = 0;
    if (ext) {
        /* Check to see if this replication session has acquired
         * a replica. If so, release it here.
         */
        consumer_connection_extension *connext = (consumer_connection_extension *)ext;
        if (NULL != connext->replica_acquired) {
            Replica *r = object_get_data((Object *)connext->replica_acquired);
            /* If a total update was in progress, abort it */
            if (REPL_PROTOCOL_50_TOTALUPDATE == connext->repl_protocol_version) {
                Slapi_PBlock *pb = slapi_pblock_new();
                const Slapi_DN *repl_root_sdn = replica_get_root(r);
                PR_ASSERT(NULL != repl_root_sdn);
                if (NULL != repl_root_sdn) {
                    slapi_pblock_set(pb, SLAPI_CONNECTION, connext->connection);
                    slapi_pblock_set(pb, SLAPI_TARGET_SDN, (void *)repl_root_sdn);
                    slapi_pblock_get(pb, SLAPI_CONN_ID, &connid);
                    slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                                  "consumer_connection_extension_destructor - "
                                  "Aborting total update in progress for replicated "
                                  "area %s connid=%" PRIu64 "\n",
                                  slapi_sdn_get_dn(repl_root_sdn), connid);
                    slapi_stop_bulk_import(pb);
                } else {
                    slapi_log_err(SLAPI_LOG_ERR, repl_plugin_name,
                                  "consumer_connection_extension_destructor - Can't determine root "
                                  "of replicated area.\n");
                }
                slapi_pblock_destroy(pb);

                /* allow reaping again */
                replica_set_tombstone_reap_stop(r, PR_FALSE);
            }
            replica_relinquish_exclusive_access(r, connid, -1);
            object_release((Object *)connext->replica_acquired);
            connext->replica_acquired = NULL;
        }

        if (connext->supplier_ruv) {
            ruv_destroy((RUV **)&connext->supplier_ruv);
        }

        if (connext->lock) {
            PR_DestroyLock(connext->lock);
            connext->lock = NULL;
        }

        connext->in_use_opid = -1;

        connext->connection = NULL;
        slapi_ch_free((void **)&ext);
    }
}

/* Obtain exclusive access to this connection extension.
 * Returns the consumer_connection_extension* if successful, else NULL.
 *
 * This is similar to obtaining exclusive access to the replica, but not identical.
 * For the connection extension, you only want to hold on to exclusive access as
 * long as it is being actively used to process an operation.  Mainly that means
 * while processing either a 'start' or an 'end' extended operation.  This makes
 * certain that if another 'start' or 'end' operation is received on the connection,
 * the ops will not trample on each other's state.  As soon as you are done with
 * that single operation, it is time to relinquish the connection extension.
 * That differs from acquiring exclusive access to the replica, which is held over
 * after the 'start' operation and relinquished during the 'end' operation.
 */
consumer_connection_extension *
consumer_connection_extension_acquire_exclusive_access(void *conn, PRUint64 connid, int opid)
{
    consumer_connection_extension *ret = NULL;

    /* step 1, grab the connext */
    consumer_connection_extension *connext = (consumer_connection_extension *)
        repl_con_get_ext(REPL_CON_EXT_CONN, conn);

    if (NULL != connext) {
        /* step 2, acquire its lock */
        PR_Lock(connext->lock);

        /* step 3, see if it is not in use, or in use by us */
        if (0 > connext->in_use_opid) {
            /* step 4, take it! */
            connext->in_use_opid = opid;
            ret = connext;
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_acquire_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Acquired consumer connection extension\n",
                          connid, opid);
        } else if (opid == connext->in_use_opid) {
            ret = connext;
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_acquire_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Reacquired consumer connection extension\n",
                          connid, opid);
        } else {
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_acquire_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Could not acquire consumer connection extension; it is in use by op=%d\n",
                          connid, opid, connext->in_use_opid);
        }

        /* step 5, drop the lock */
        PR_Unlock(connext->lock);
    } else {
        slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                      "consumer_connection_extension_acquire_exclusive_access - "
                      "conn=%" PRIu64 " op=%d Could not acquire consumer extension, it is NULL!\n",
                      connid, opid);
    }

    return ret;
}

/* Relinquish exclusive access to this connection extension.
 * Returns 0 if exclusive access could NOT be relinquished, and non-zero if it was.
 * Specifically:
 *      1 if the extension was in use and was relinquished.
 *      2 if the extension was not in use to begin with.
 *
 * The extension will only be relinquished if it was first acquired by this op,
 * or if 'force' is TRUE.  Do not use 'force' without a legitimate reason, such
 * as when destroying the parent connection.
 *
 * cf. consumer_connection_extension_acquire_exclusive_access() for details on how,
 * when, and why you would want to acquire and relinquish exclusive access.
 */
int
consumer_connection_extension_relinquish_exclusive_access(void *conn, PRUint64 connid, int opid, PRBool force)
{
    int ret = 0;

    /* step 1, grab the connext */
    consumer_connection_extension *connext = (consumer_connection_extension *)
        repl_con_get_ext(REPL_CON_EXT_CONN, conn);

    if (NULL != connext) {
        /* step 2, acquire its lock */
        PR_Lock(connext->lock);

        /* step 3, see if it is in use */
        if (0 > connext->in_use_opid) {
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_relinquish_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Consumer connection extension is not in use\n",
                          connid, opid);
            ret = 2;
        } else if (opid == connext->in_use_opid) {
            /* step 4, relinquish it (normal) */
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_relinquish_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Relinquishing consumer connection extension\n",
                          connid, opid);
            connext->in_use_opid = -1;
            ret = 1;
        } else if (force) {
            /* step 4, relinquish it (forced) */
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_relinquish_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Forced to relinquish consumer connection extension held by op=%d\n",
                          connid, opid, connext->in_use_opid);
            connext->in_use_opid = -1;
            ret = 1;
        } else {
            slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                          "consumer_connection_extension_relinquish_exclusive_access - "
                          "conn=%" PRIu64 " op=%d Not relinquishing consumer connection extension, it is held by op=%d!\n",
                          connid, opid, connext->in_use_opid);
        }

        /* step 5, drop the lock */
        PR_Unlock(connext->lock);
    } else {
        slapi_log_err(SLAPI_LOG_REPL, repl_plugin_name,
                      "consumer_connection_extension_relinquish_exclusive_access - "
                      "conn=%" PRIu64 " op=%d Could not relinquish consumer extension, it is NULL!\n",
                      connid, opid);
    }

    return ret;
}