389-ds-base/ldap/servers/plugins/sync/sync_refresh.c

/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2013 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details. 
 * END COPYRIGHT BLOCK **/

#include "sync.h"

static SyncOpInfo *new_SyncOpInfo(int flag, PRThread *tid, Sync_Cookie *cookie);

static int sync_extension_type;
static int sync_extension_handle;

static SyncOpInfo *sync_get_operation_extension(Slapi_PBlock *pb);
static void sync_set_operation_extension(Slapi_PBlock *pb, SyncOpInfo *spec);
static int sync_find_ref_by_uuid(Sync_UpdateNode *updates, int stop, char *uniqueid);
static void sync_free_update_nodes (Sync_UpdateNode **updates, int count);
Slapi_Entry *sync_deleted_entry_from_changelog(Slapi_Entry *cl_entry);
static int sync_feature_allowed (Slapi_PBlock *pb);

static int sync_feature_allowed (Slapi_PBlock *pb)
{
	int isroot = 0;
	int ldapcode = LDAP_SUCCESS;

	slapi_pblock_get(pb, SLAPI_REQUESTOR_ISROOT, &isroot);
	if ( !isroot) {
		char *dn;
		Slapi_Entry *feature = NULL;

		/* Fetch the feature entry and see if the requestor is allowed access. */
		dn = slapi_ch_smprintf("dn: oid=%s,cn=features,cn=config", LDAP_CONTROL_SYNC);
		if ((feature = slapi_str2entry(dn,0)) != NULL) {
			char *dummy_attr = "1.1";

			ldapcode = slapi_access_allowed(pb, feature, dummy_attr, NULL, SLAPI_ACL_READ);
		}

		/* If the feature entry does not exist, deny use of the control.  Only
		 * the root DN will be allowed to use the control in this case. */
		if ((feature == NULL) || (ldapcode != LDAP_SUCCESS)) {
			ldapcode = LDAP_INSUFFICIENT_ACCESS;
		}
		slapi_ch_free((void **)&dn);
		slapi_entry_free(feature);
	}
	return(ldapcode);
}

int sync_srch_refresh_pre_search(Slapi_PBlock *pb)
{

	LDAPControl **requestcontrols;
	struct berval	*psbvp;
	Sync_Cookie *client_cookie = NULL;
	Sync_Cookie *session_cookie = NULL;
	int 	rc = 0;
	int sync_persist = 0;
	PRThread *tid = NULL;
	int entries_sent = 0;

	slapi_pblock_get (pb, SLAPI_REQCONTROLS, &requestcontrols);
	if ( slapi_control_present( requestcontrols, LDAP_CONTROL_SYNC, &psbvp, NULL )){
		char *cookie = NULL;
		int mode = 1;
		int refresh = 0;

		if ( sync_parse_control_value( psbvp, &mode,
									 &refresh, &cookie ) != LDAP_SUCCESS )
		{
			rc = 1;
			goto error_return;
		} else {
			/* control is valid, check if usere is allowed to perform sync searches */
			rc = sync_feature_allowed(pb);
			if (rc) {
				sync_result_err(pb,rc,NULL);
				goto error_return;
			}
		}

		if ( mode == 1 || mode == 3 )
		{

			/* we need to return a cookie in the result message
			 * indicating a state to be used in future sessions
			 * as starting point - create it now
			 */
			session_cookie = sync_cookie_create(pb);
			/*
			 *  if mode is persist we need to setup the persit handler
			 * to catch the mods while the refresh is done 
			 */
			if ( mode == 3 )
			{
				tid = sync_persist_add(pb);
				if ( tid ) 
					sync_persist = 1;
				else {
					rc = LDAP_UNWILLING_TO_PERFORM;
					sync_result_err(pb,rc,"Too many active synchronization sessions");
					goto error_return;
				}
			}
			/* 
			 * now handl the refresh request
			 * there are two scenarios
			 * 1. no cookie is provided this means send all entries matching the search request
			 * 2. a cookie is provided: send all entries changed since the cookie was issued
			 * 	-- return an error if the cookie is invalid
			 * 	-- return e-syncRefreshRequired if the data referenced in the cookie are no
			 * 		longer in the history
			*/
			if (cookie) {
				if ((client_cookie = sync_cookie_parse (cookie)) &&
				    sync_cookie_isvalid(client_cookie, session_cookie))
				{
					rc = sync_refresh_update_content(pb, client_cookie, session_cookie);
					if (rc == 0) 
						entries_sent = 1;
					if (sync_persist)
						rc = sync_intermediate_msg(pb, LDAP_TAG_SYNC_REFRESH_DELETE, session_cookie, NULL);
					else
						rc = sync_result_msg(pb, session_cookie);
				} else {
					rc = E_SYNC_REFRESH_REQUIRED;
					sync_result_err(pb,rc, "Invalid session cookie");
				}
			} else {
				rc = sync_refresh_initial_content (pb, sync_persist,  tid, session_cookie);
				if (rc == 0 && !sync_persist)
					/* maintained in postop code */
					session_cookie = NULL;
					/* if persis it will be handed over to persist code */
			}
			
			if ( rc ) {
				if (sync_persist)
					sync_persist_terminate (tid);
				goto error_return;
			} else if (sync_persist){
				Slapi_Operation *operation;

				slapi_pblock_get(pb, SLAPI_OPERATION, &operation);
				if (client_cookie) {
					rc = sync_persist_startup(tid, session_cookie);
				}
				if (rc == 0) {
					session_cookie = NULL; /* maintained in persist code */
					slapi_operation_set_flag(operation, OP_FLAG_SYNC_PERSIST);
				}
			}
			

		} else {
			/* unknown mode, return an error */
			rc = 1;
		}
error_return:
	sync_cookie_free(&client_cookie);
	sync_cookie_free(&session_cookie);
	slapi_ch_free((void **)&cookie);
	}

	/* if we sent the entries
	 * return "error" to abort normal search
	 */ 
	if (  entries_sent > 0 ) {
		return(1);
	} else {
		return(rc);
	}
}

int sync_srch_refresh_post_search(Slapi_PBlock *pb)
{
	int rc = 0;
	SyncOpInfo *info = sync_get_operation_extension(pb);

	if (!info) {
		return (0); /* nothing to do */
	}
	if (info->send_flag & SYNC_FLAG_SEND_INTERMEDIATE) {
		rc = sync_intermediate_msg(pb, LDAP_TAG_SYNC_REFRESH_DELETE, info->cookie, NULL);
		/* the refresh phase is over, now the post op
		 * plugins will create the state control 
		 * depending on the operation type, reset flag
		 */
		info->send_flag &= ~SYNC_FLAG_ADD_STATE_CTRL;
		/* activate the persistent phase thread*/
		sync_persist_startup(info->tid, info->cookie);
	}
	if (info->send_flag & SYNC_FLAG_ADD_DONE_CTRL) {
		LDAPControl **ctrl = (LDAPControl **)slapi_ch_calloc(2, sizeof (LDAPControl *));
		char *cookiestr = sync_cookie2str(info->cookie);
		sync_create_sync_done_control( &ctrl[0], 0, cookiestr);
		slapi_pblock_set(pb, SLAPI_RESCONTROLS, ctrl);
		slapi_ch_free((void **)&cookiestr);
	}
	return(rc);
}

int sync_srch_refresh_pre_entry(Slapi_PBlock *pb)
{
	int rc = 0;
	SyncOpInfo *info = sync_get_operation_extension(pb);

	if (!info) {
		rc = 0; /* nothing to do */
	} else if (info->send_flag & SYNC_FLAG_ADD_STATE_CTRL) {
		Slapi_Entry *e;
		slapi_pblock_get(pb, SLAPI_SEARCH_RESULT_ENTRY, &e);
		LDAPControl **ctrl = (LDAPControl **)slapi_ch_calloc(2, sizeof (LDAPControl *));
		sync_create_state_control(e, &ctrl[0], LDAP_SYNC_ADD, NULL);
		slapi_pblock_set(pb, SLAPI_SEARCH_CTRLS, ctrl);
	}
	return(rc);
}

int sync_srch_refresh_pre_result(Slapi_PBlock *pb)
{
	SyncOpInfo *info = sync_get_operation_extension(pb);

	if (!info) {
		return 0; /* nothing to do */
	}
	if (info->send_flag & SYNC_FLAG_NO_RESULT ) {
		return(1);
	} else {
		return(0);
	}
}

static void
sync_free_update_nodes (Sync_UpdateNode **updates, int count)
{
	int i;

	for (i=0; i<count;i++) {
		if ((*updates)[i].upd_uuid)
			slapi_ch_free((void **)&((*updates)[i].upd_uuid));
		if ((*updates)[i].upd_e)
			slapi_entry_free((*updates)[i].upd_e);
	}
	slapi_ch_free((void **)updates);
}

int
sync_refresh_update_content(Slapi_PBlock *pb, Sync_Cookie *client_cookie, Sync_Cookie *server_cookie)
{
	Slapi_PBlock *seq_pb;
	char *filter;
	Sync_CallBackData cb_data;
	int rc;
	int chg_count = server_cookie->cookie_change_info -
			client_cookie->cookie_change_info + 1;

	cb_data.cb_updates = (Sync_UpdateNode *)slapi_ch_calloc(chg_count, sizeof(Sync_UpdateNode));

	seq_pb = slapi_pblock_new();
	slapi_pblock_init(seq_pb);

	cb_data.orig_pb = pb;
	cb_data.change_start = client_cookie->cookie_change_info;

	filter = slapi_ch_smprintf("(&(changenumber>=%lu)(changenumber<=%lu))",
	                           client_cookie->cookie_change_info,
	                           server_cookie->cookie_change_info);
	slapi_search_internal_set_pb(
		seq_pb, 
		CL_SRCH_BASE,
		LDAP_SCOPE_ONE,
		filter,
		NULL,
		0,
		NULL, NULL, 
		plugin_get_default_component_id(),
		0);

	rc = slapi_search_internal_callback_pb (
		seq_pb, &cb_data, NULL, sync_read_entry_from_changelog, NULL);
	slapi_pblock_destroy(seq_pb);

	/* Now send the deleted entries in a sync info message 
	 * and the modified entries as single entries
	 */
	sync_send_deleted_entries(pb, cb_data.cb_updates, chg_count, server_cookie);
	sync_send_modified_entries(pb, cb_data.cb_updates, chg_count); 

	sync_free_update_nodes(&cb_data.cb_updates, chg_count);
	slapi_ch_free((void **)&filter);
	return (rc);
}

int
sync_refresh_initial_content(Slapi_PBlock *pb, int sync_persist, PRThread *tid, Sync_Cookie *sc)
{
	/* the entries will be sent in the normal search process, but
	 * - a control has to be sent with each entry
	 *   if sync persist:
	 *   - an intermediate response has to be sent
	 *   - no result message must be sent
	 *
	 *   else
	 *   - a result message with a sync done control has to be sent
	 *
	 *   setup on operation extension to take care of in 
	 *   pre_entry, pre_result and post_search plugins
	 */
	 SyncOpInfo *info;

	if (sync_persist) {
		info = new_SyncOpInfo
			(SYNC_FLAG_ADD_STATE_CTRL |
				SYNC_FLAG_SEND_INTERMEDIATE |
				SYNC_FLAG_NO_RESULT,
				tid,
				sc);
	} else {
		info = new_SyncOpInfo
			(SYNC_FLAG_ADD_STATE_CTRL |
				SYNC_FLAG_ADD_DONE_CTRL,
				tid,
				sc);
	}
	sync_set_operation_extension(pb, info);
     
	return(0);
}

static int
sync_str2chgreq(char *chgtype)
{
	if (chgtype == NULL) {
		return(-1);
	}
	if (strcasecmp(chgtype,"add") == 0) {
		return(LDAP_REQ_ADD);
	} else if (strcasecmp(chgtype,"modify") == 0) {
		return(LDAP_REQ_MODIFY);
	} else if (strcasecmp(chgtype,"modrdn") == 0) {
		return(LDAP_REQ_MODRDN);
	} else if (strcasecmp(chgtype,"delete") == 0) {
		return(LDAP_REQ_DELETE);
	} else {
		return(-1);
	}
}

static char*
sync_get_attr_value_from_entry( Slapi_Entry *cl_entry, char *attrtype)
{
	Slapi_Value *sval=NULL;
	const struct berval *value;
	char *strvalue = NULL;
	if ( NULL != cl_entry ) {
		Slapi_Attr *chattr = NULL;
		sval = NULL;
		value = NULL;
		if ( slapi_entry_attr_find( cl_entry, attrtype, &chattr ) == 0 ) {
			slapi_attr_first_value( chattr,&sval );
			if ( NULL != sval ) {
				value = slapi_value_get_berval ( sval );
				if( NULL != value && NULL != value->bv_val &&
					'\0' != value->bv_val[0]) {
					strvalue = slapi_ch_strdup( value->bv_val);
				}
			}
		}
	}
	return (strvalue);
}

static int
sync_find_ref_by_uuid(Sync_UpdateNode *updates, int stop, char *uniqueid)
{
	int rc = -1;
	int i;
	for (i=0; i<stop; i++) {
		if ( updates[i].upd_uuid && (0 == strcmp(uniqueid, updates[i].upd_uuid))) {
			rc = i;
			break;
		}
	}
	return (rc);
}

static int
sync_is_entry_in_scope(Slapi_PBlock *pb, Slapi_Entry *db_entry)
{
	Slapi_Filter *origfilter;
	slapi_pblock_get( pb, SLAPI_SEARCH_FILTER, &origfilter );
	if (db_entry &&
		sync_is_active(db_entry, pb) &&
		(slapi_vattr_filter_test( pb, db_entry, origfilter, 1) == 0)) {
			return(1);
	} else {
		return(0);
	}
}

Slapi_Entry *
sync_deleted_entry_from_changelog(Slapi_Entry *cl_entry)
{
	Slapi_Entry *db_entry = NULL;
	char *entrydn = NULL;
	char *uniqueid = NULL;
	
	entrydn = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_ENTRYDN);
	uniqueid = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_UNIQUEID);

	/* when the Retro CL can provide the deleted entry 
	 * the entry will be taken from th RCL.
	 * For now. just create an entry to holde the nsuniqueid
	 */ 
	db_entry = slapi_entry_alloc();
	slapi_entry_init(db_entry, entrydn, NULL);
	slapi_entry_add_string(db_entry, "nsuniqueid", uniqueid);
	slapi_ch_free((void**)&uniqueid);

	return(db_entry);
}

int
sync_read_entry_from_changelog( Slapi_Entry *cl_entry, void *cb_data)
{
	char *uniqueid = NULL;
	char *chgtype = NULL;
	char *chgnr = NULL;
	int chg_req;
	int prev = 0;
	int index = 0;
	unsigned long chgnum = 0;
	Sync_CallBackData *cb = (Sync_CallBackData *) cb_data;

	if (cb == NULL) {
		return(1);
	}

	uniqueid = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_UNIQUEID);
	if (uniqueid == NULL) {
		slapi_log_error (SLAPI_LOG_FATAL, SYNC_PLUGIN_SUBSYSTEM, 
			"Retro Changelog does not provied nsuniquedid."
			"Check RCL plugin configuration.\n" );
		return(1);
	}
	chgnr = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_CHANGENUMBER);
	chgnum = sync_number2ulong(chgnr);
	if (SYNC_INVALID_CHANGENUM == chgnum) {
		slapi_log_error (SLAPI_LOG_FATAL, SYNC_PLUGIN_SUBSYSTEM, 
			"Change number provided by Retro Changelog is invalid: %s\n", chgnr);
		slapi_ch_free_string(&chgnr);
		slapi_ch_free_string(&uniqueid);
		return(1);
	}
	if (chgnum < cb->change_start) {
		slapi_log_error (SLAPI_LOG_FATAL, SYNC_PLUGIN_SUBSYSTEM, 
			"Change number provided by Retro Changelog %s is less than the initial number %lu\n",
			chgnr, cb->change_start);
		slapi_ch_free_string(&chgnr);
		slapi_ch_free_string(&uniqueid);
		return(1);
	}
	index = chgnum - cb->change_start;
	chgtype = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_CHGTYPE);
	chg_req = sync_str2chgreq(chgtype);
	switch (chg_req){ 
		case LDAP_REQ_ADD:
			/* nsuniqueid cannot exist, just add reference */
			cb->cb_updates[index].upd_chgtype = LDAP_REQ_ADD;
			cb->cb_updates[index].upd_uuid = uniqueid;
			break;
		case LDAP_REQ_MODIFY:
			/* check if we have seen this uuid already */
			prev = sync_find_ref_by_uuid(cb->cb_updates, index, uniqueid);
			if (prev == -1) {
				cb->cb_updates[index].upd_chgtype = LDAP_REQ_MODIFY;
				cb->cb_updates[index].upd_uuid = uniqueid;
			} else {
				/* was add or mod, keep it */
				cb->cb_updates[index].upd_uuid = 0;
				cb->cb_updates[index].upd_chgtype = 0;
				slapi_ch_free_string(&uniqueid);
			}
			break;
		case LDAP_REQ_MODRDN:
			{
				/* if it is a modrdn, we finally need to decide if this will
				 * trigger a present or delete state, keep the info that
				 * the entry was subject to a modrdn
				 */
			int new_scope = 0;
			int old_scope = 0;
			Slapi_DN *original_dn;
			char *newsuperior = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_NEWSUPERIOR);
			char *entrydn = sync_get_attr_value_from_entry (cl_entry, CL_ATTR_ENTRYDN);
			/* if newsuperior is set we need to checkif the entry has been moved into
			 * or moved out of the scope of the synchronization request
			 */
			original_dn = slapi_sdn_new_dn_byref(entrydn);
			old_scope = sync_is_active_scope(original_dn,cb->orig_pb);
			slapi_sdn_free(&original_dn);
			slapi_ch_free_string(&entrydn);
			if (newsuperior) {
				Slapi_DN *newbase;
				newbase = slapi_sdn_new_dn_byref(newsuperior);
				new_scope = sync_is_active_scope(newbase, cb->orig_pb);
				slapi_ch_free_string(&newsuperior);
				slapi_sdn_free(&newbase);
			} else {
				/* scope didn't change */
				new_scope = old_scope;
			}
			prev = sync_find_ref_by_uuid(cb->cb_updates, index, uniqueid);
			if ( old_scope && new_scope ) {
				/* nothing changed, it's just a MOD */
				if (prev == -1) {
					cb->cb_updates[index].upd_chgtype = LDAP_REQ_MODIFY;
					cb->cb_updates[index].upd_uuid = uniqueid;
				} else {
					cb->cb_updates[index].upd_uuid = 0;
					cb->cb_updates[index].upd_chgtype = 0;
					slapi_ch_free_string(&uniqueid);
				}
			} else if ( old_scope ) {
				/* it was moved out of scope, handle as DEL */
				if (prev == -1) {
					cb->cb_updates[index].upd_chgtype = LDAP_REQ_DELETE;
					cb->cb_updates[index].upd_uuid = uniqueid;
					cb->cb_updates[index].upd_e = sync_deleted_entry_from_changelog(cl_entry);
				} else {
					cb->cb_updates[prev].upd_chgtype = LDAP_REQ_DELETE;
					cb->cb_updates[prev].upd_e = sync_deleted_entry_from_changelog(cl_entry);
					slapi_ch_free_string(&uniqueid);
				}
			} else if ( new_scope ) {
				/* moved into scope, handle as ADD */
					cb->cb_updates[index].upd_chgtype = LDAP_REQ_ADD;
					cb->cb_updates[index].upd_uuid = uniqueid;
			} else {
				/* nothing to do */
				slapi_ch_free_string(&uniqueid);
 			}
			slapi_sdn_free(&original_dn);
			break;
			}
		case LDAP_REQ_DELETE:
			/* check if we have seen this uuid already */
			prev = sync_find_ref_by_uuid(cb->cb_updates, index, uniqueid);
			if (prev == -1) {
				cb->cb_updates[index].upd_chgtype = LDAP_REQ_DELETE;
				cb->cb_updates[index].upd_uuid = uniqueid;
				cb->cb_updates[index].upd_e = sync_deleted_entry_from_changelog(cl_entry);
			} else {
				/* if it was added since last cookie state, we
				 * can ignoere it */				
				if (cb->cb_updates[prev].upd_chgtype == LDAP_REQ_ADD) {
					slapi_ch_free_string(&(cb->cb_updates[prev].upd_uuid));
					cb->cb_updates[prev].upd_uuid = NULL;
					cb->cb_updates[index].upd_uuid = NULL;
				} else {
					/* ignore previous mod */
					cb->cb_updates[index].upd_uuid = NULL;
					cb->cb_updates[prev].upd_chgtype = LDAP_REQ_DELETE;
					cb->cb_updates[prev].upd_e = sync_deleted_entry_from_changelog(cl_entry);
				}
				slapi_ch_free_string(&uniqueid);
			}
			break;
		default:
			slapi_ch_free_string(&uniqueid);
	}
	slapi_ch_free_string(&chgtype);
	slapi_ch_free_string(&chgnr);

	return (0);
}
#define SYNC_MAX_DELETED_UUID_BATCH 50

void
sync_send_deleted_entries(Slapi_PBlock *pb, Sync_UpdateNode *upd, int chg_count, Sync_Cookie *cookie)
{
	char *syncUUIDs[SYNC_MAX_DELETED_UUID_BATCH + 1];
	int uuid_index = 0;
	int index, i;

	syncUUIDs[0] = NULL;
	for (index=0; index < chg_count; index++) {
		if (upd[index].upd_chgtype == LDAP_REQ_DELETE &&
			upd[index].upd_uuid ) {
			if (uuid_index < SYNC_MAX_DELETED_UUID_BATCH) {
				syncUUIDs[uuid_index++] = sync_nsuniqueid2uuid(upd[index].upd_uuid);
			} else {
				/* max number of uuids to be sent in one sync info message */
				syncUUIDs[uuid_index] = NULL;
				sync_intermediate_msg (pb, LDAP_TAG_SYNC_ID_SET, cookie, &syncUUIDs[0]);
				for (i=0; i<uuid_index;i++) {
					slapi_ch_free((void **)&syncUUIDs[i]);
					syncUUIDs[i] = NULL;
				}
				uuid_index = 0;
			}
		}
	}

	if (uuid_index > 0 && syncUUIDs[uuid_index-1]) {
		/* more entries to send */
		syncUUIDs[uuid_index] = NULL;
		sync_intermediate_msg (pb, LDAP_TAG_SYNC_ID_SET, cookie, &syncUUIDs[0]);
		for (i=0; i<uuid_index;i++) {
			slapi_ch_free((void **)&syncUUIDs[i]);
			syncUUIDs[i] = NULL;
		}
	}
}

void
sync_send_modified_entries(Slapi_PBlock *pb, Sync_UpdateNode *upd, int chg_count)
{
	int index;

	for (index=0; index < chg_count; index++) {
		if (upd[index].upd_chgtype != LDAP_REQ_DELETE &&
			upd[index].upd_uuid )

			sync_send_entry_from_changelog(pb, upd[index].upd_chgtype, upd[index].upd_uuid);
	}
}

int
sync_send_entry_from_changelog(Slapi_PBlock *pb,int chg_req, char *uniqueid)
{
	Slapi_Entry *db_entry = NULL;
	int chg_type = LDAP_SYNC_ADD;
	int rv;
	Slapi_PBlock *search_pb = NULL;
    	Slapi_Entry **entries = NULL;
	char *origbase;
	char *filter = slapi_ch_smprintf("(nsuniqueid=%s)",uniqueid);

	slapi_pblock_get( pb, SLAPI_ORIGINAL_TARGET_DN, &origbase );
	search_pb = slapi_pblock_new();
    	slapi_search_internal_set_pb(search_pb, origbase,
           				LDAP_SCOPE_SUBTREE, filter,
            				NULL, 0, NULL, NULL, plugin_get_default_component_id(), 0);
 	slapi_search_internal_pb(search_pb);
	slapi_pblock_get(search_pb, SLAPI_PLUGIN_INTOP_RESULT, &rv);
	if ( rv == LDAP_SUCCESS) {
		slapi_pblock_get(search_pb, SLAPI_PLUGIN_INTOP_SEARCH_ENTRIES, &entries);
    		if (entries)
			db_entry = *entries; /* there can only be one */
	}

	if (db_entry && sync_is_entry_in_scope(pb, db_entry)) {
		LDAPControl **ctrl = (LDAPControl **)slapi_ch_calloc(2, sizeof (LDAPControl *));
		sync_create_state_control(db_entry, &ctrl[0], chg_type, NULL);
		slapi_send_ldap_search_entry (pb, db_entry, ctrl, NULL, 0);
		ldap_controls_free(ctrl);
	}
	slapi_free_search_results_internal(search_pb);
	slapi_pblock_destroy(search_pb);
	slapi_ch_free((void **)&filter);
	return (0);
}

static SyncOpInfo*
new_SyncOpInfo(int flag, PRThread *tid, Sync_Cookie *cookie) {
    SyncOpInfo *spec = (SyncOpInfo *)slapi_ch_calloc(1, sizeof(SyncOpInfo));
    spec->send_flag = flag;
    spec->cookie = cookie;
    spec->tid = tid;

    return spec;
}
/* consumer operation extension constructor */
static void *
sync_operation_extension_ctor(void *object, void *parent)
{
    /* we only set the extension value explicitly if the
       client requested the control - see deref_pre_search */
    return NULL; /* we don't set anything in the ctor */
}

/* consumer operation extension destructor */
static void 
sync_delete_SyncOpInfo(SyncOpInfo **info)
{
	if (info && *info) {
		sync_cookie_free(&((*info)->cookie));
        	slapi_ch_free((void **)info);
	}
}

static void
sync_operation_extension_dtor(void *ext, void *object, void *parent)
{
   SyncOpInfo *spec = (SyncOpInfo *)ext;
    sync_delete_SyncOpInfo(&spec);
}

static SyncOpInfo *
sync_get_operation_extension(Slapi_PBlock *pb)
{
    Slapi_Operation *op;

    slapi_pblock_get(pb, SLAPI_OPERATION, &op);
    return (SyncOpInfo *)slapi_get_object_extension(sync_extension_type,
                                                             op, sync_extension_handle);
}

static void
sync_set_operation_extension(Slapi_PBlock *pb, SyncOpInfo *spec)
{
    Slapi_Operation *op;

    slapi_pblock_get(pb, SLAPI_OPERATION, &op);
    slapi_set_object_extension(sync_extension_type, op,
                               sync_extension_handle, (void *)spec);
}

int
sync_register_operation_extension(void)
{
	return slapi_register_object_extension(SYNC_PLUGIN_SUBSYSTEM,
                                           SLAPI_EXT_OPERATION, 
                                           sync_operation_extension_ctor,
                                           sync_operation_extension_dtor,
                                           &sync_extension_type,
                                           &sync_extension_handle);
}

int
sync_unregister_operation_entension(void)
{
    int rc = slapi_unregister_object_extension(SYNC_PLUGIN_SUBSYSTEM,
                                               SLAPI_EXT_OPERATION,
                                               &sync_extension_type,
                                               &sync_extension_handle);

    return rc;
}