search.c

OpenLdap是LDAP的开源项目

	/*
	 * Rewrite the search base, if required
	 */
	dc->target = mt;
	dc->ctx = "searchBase";
	switch ( ldap_back_dn_massage( dc, &realbase, &mbase ) ) {
	case LDAP_SUCCESS:
		break;

	case LDAP_UNWILLING_TO_PERFORM:
		rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
		rs->sr_text = "Operation not allowed";
		send_ldap_result( op, rs );
		retcode = META_SEARCH_ERR;
		goto doreturn;

	default:

		/*
		 * this target is no longer candidate
		 */
		retcode = META_SEARCH_NOT_CANDIDATE;
		goto doreturn;
	}

	/*
	 * Maps filter
	 */
	rc = ldap_back_filter_map_rewrite( dc, op->ors_filter,
			&mfilter, BACKLDAP_MAP );
	switch ( rc ) {
	case LDAP_SUCCESS:
		break;

	case LDAP_COMPARE_FALSE:
	default:
		/*
		 * this target is no longer candidate
		 */
		retcode = META_SEARCH_NOT_CANDIDATE;
		goto done;
	}

	/*
	 * Maps required attributes
	 */
	rc = ldap_back_map_attrs( &mt->mt_rwmap.rwm_at,
			op->ors_attrs, BACKLDAP_MAP, &mapped_attrs );
	if ( rc != LDAP_SUCCESS ) {
		/*
		 * this target is no longer candidate
		 */
		retcode = META_SEARCH_NOT_CANDIDATE;
		goto done;
	}

	/* should we check return values? */
	if ( op->ors_deref != -1 ) {
		assert( msc->msc_ld != NULL );
		(void)ldap_set_option( msc->msc_ld, LDAP_OPT_DEREF,
				( void * )&op->ors_deref );
	}

	if ( op->ors_tlimit != SLAP_NO_LIMIT ) {
		tv.tv_sec = op->ors_tlimit > 0 ? op->ors_tlimit : 1;
		tv.tv_usec = 0;
		tvp = &tv;
	}

retry:;
	ctrls = op->o_ctrls;
	if ( ldap_back_proxy_authz_ctrl( &msc->msc_bound_ndn,
		mt->mt_version, &mt->mt_idassert, op, rs, &ctrls )
		!= LDAP_SUCCESS )
	{
		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
		retcode = META_SEARCH_NOT_CANDIDATE;
		goto done;
	}

	/*
	 * Starts the search
	 */
	assert( msc->msc_ld != NULL );
	rc = ldap_search_ext( msc->msc_ld,
			mbase.bv_val, realscope, mfilter.bv_val,
			mapped_attrs, op->ors_attrsonly,
			ctrls, NULL, tvp, op->ors_slimit,
			&candidates[ candidate ].sr_msgid ); 
	switch ( rc ) {
	case LDAP_SUCCESS:
		retcode = META_SEARCH_CANDIDATE;
		break;
	
	case LDAP_SERVER_DOWN:
		if ( nretries && meta_back_retry( op, rs, mcp, candidate, LDAP_BACK_DONTSEND ) ) {
			nretries = 0;
			/* if the identity changed, there might be need to re-authz */
			(void)ldap_back_proxy_authz_ctrl_free( op, &ctrls );
			goto retry;
		}

		if ( *mcp == NULL ) {
			retcode = META_SEARCH_ERR;
			candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
			break;
		}
		/* fall thru */

	default:
		candidates[ candidate ].sr_msgid = META_MSGID_IGNORE;
		retcode = META_SEARCH_NOT_CANDIDATE;
	}

done:;
	(void)ldap_back_proxy_authz_ctrl_free( op, &ctrls );

	if ( mapped_attrs ) {
		free( mapped_attrs );
	}
	if ( mfilter.bv_val != op->ors_filterstr.bv_val ) {
		free( mfilter.bv_val );
	}
	if ( mbase.bv_val != realbase.bv_val ) {
		free( mbase.bv_val );
	}

doreturn:;
	Debug( LDAP_DEBUG_TRACE, "%s <<< meta_back_search_start[%d]=%d\n", op->o_log_prefix, candidate, retcode );

	return retcode;
}

int
meta_back_search( Operation *op, SlapReply *rs )
{
	metainfo_t	*mi = ( metainfo_t * )op->o_bd->be_private;
	metaconn_t	*mc;
	struct timeval	save_tv = { 0, 0 },
			tv;
	time_t		stoptime = (time_t)(-1),
			lastres_time = slap_get_time(),
			timeout = 0;
	int		rc = 0, sres = LDAP_SUCCESS;
	char		*matched = NULL;
	int		last = 0, ncandidates = 0,
			initial_candidates = 0, candidate_match = 0,
			needbind = 0;
	ldap_back_send_t	sendok = LDAP_BACK_SENDERR;
	long		i;
	dncookie	dc;
	int		is_ok = 0;
	void		*savepriv;
	SlapReply	*candidates = meta_back_candidates_get( op );

	/*
	 * controls are set in ldap_back_dobind()
	 * 
	 * FIXME: in case of values return filter, we might want
	 * to map attrs and maybe rewrite value
	 */
getconn:;
	mc = meta_back_getconn( op, rs, NULL, sendok );
	if ( !mc ) {
		return rs->sr_err;
	}

	dc.conn = op->o_conn;
	dc.rs = rs;

	/*
	 * Inits searches
	 */
	for ( i = 0; i < mi->mi_ntargets; i++ ) {
		/* reset sr_msgid; it is used in most loops
		 * to check if that target is still to be considered */
		candidates[ i ].sr_msgid = META_MSGID_IGNORE;

		/* a target is marked as candidate by meta_back_getconn();
		 * if for any reason (an error, it's over or so) it is
		 * no longer active, sr_msgid is set to META_MSGID_IGNORE
		 * but it remains candidate, which means it has been active
		 * at some point during the operation.  This allows to 
		 * use its response code and more to compute the final
		 * response */
		if ( !META_IS_CANDIDATE( &candidates[ i ] ) ) {
			continue;
		}

		candidates[ i ].sr_matched = NULL;
		candidates[ i ].sr_text = NULL;
		candidates[ i ].sr_ref = NULL;
		candidates[ i ].sr_ctrls = NULL;

		/* get largest timeout among candidates */
		if ( mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ]
			&& mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ] > timeout )
		{
			timeout = mi->mi_targets[ i ]->mt_timeout[ SLAP_OP_SEARCH ];
		}
	}

	for ( i = 0; i < mi->mi_ntargets; i++ ) {
		if ( !META_IS_CANDIDATE( &candidates[ i ] )
			|| candidates[ i ].sr_err != LDAP_SUCCESS )
		{
			continue;
		}

		switch ( meta_back_search_start( op, rs, &dc, &mc, i, candidates ) )
		{
		case META_SEARCH_NOT_CANDIDATE:
			candidates[ i ].sr_msgid = META_MSGID_IGNORE;
			break;

		case META_SEARCH_NEED_BIND:
			++needbind;
			/* fallthru */

		case META_SEARCH_CANDIDATE:
		case META_SEARCH_BINDING:
			candidates[ i ].sr_type = REP_INTERMEDIATE;
			++ncandidates;
			break;

		case META_SEARCH_ERR:
			savepriv = op->o_private;
			op->o_private = (void *)i;
			send_ldap_result( op, rs );
			op->o_private = savepriv;
			rc = -1;
			goto finish;

		default:
			assert( 0 );
			break;
		}
	}

	if ( ncandidates > 0 && needbind == ncandidates ) {
		/*
		 * give up the second time...
		 *
		 * NOTE: this should not occur the second time, since a fresh
		 * connection has ben created; however, targets may also
		 * need bind because the bind timed out or so.
		 */
		if ( sendok & LDAP_BACK_BINDING ) {
			Debug( LDAP_DEBUG_ANY,
				"%s meta_back_search: unable to initialize conn\n",
				op->o_log_prefix, 0, 0 );
			rs->sr_err = LDAP_UNAVAILABLE;
			rs->sr_text = "unable to initialize connection to remote targets";
			send_ldap_result( op, rs );
			rc = -1;
			goto finish;
		}

		/* FIXME: better create a separate connection? */
		sendok |= LDAP_BACK_BINDING;

#ifdef DEBUG_205
		Debug( LDAP_DEBUG_ANY, "*** %s drop mc=%p create new connection\n",
			op->o_log_prefix, (void *)mc, 0 );
#endif /* DEBUG_205 */

		meta_back_release_conn( mi, mc );
		mc = NULL;

		needbind = 0;
		ncandidates = 0;

		goto getconn;
	}

	initial_candidates = ncandidates;

	if ( StatslogTest( LDAP_DEBUG_TRACE ) ) {
		char	cnd[ SLAP_TEXT_BUFLEN ];
		int	c;

		for ( c = 0; c < mi->mi_ntargets; c++ ) {
			if ( META_IS_CANDIDATE( &candidates[ c ] ) ) {
				cnd[ c ] = '*';
			} else {
				cnd[ c ] = ' ';
			}
		}
		cnd[ c ] = '\0';

		Debug( LDAP_DEBUG_TRACE, "%s meta_back_search: ncandidates=%d "
			"cnd=\"%s\"\n", op->o_log_prefix, ncandidates, cnd );
	}

	if ( initial_candidates == 0 ) {
		/* NOTE: here we are not sending any matchedDN;
		 * this is intended, because if the back-meta
		 * is serving this search request, but no valid
		 * candidate could be looked up, it means that
		 * there is a hole in the mapping of the targets
		 * and thus no knowledge of any remote superior
		 * is available */
		Debug( LDAP_DEBUG_ANY, "%s meta_back_search: "
			"base=\"%s\" scope=%d: "
			"no candidate could be selected\n",
			op->o_log_prefix, op->o_req_dn.bv_val,
			op->ors_scope );

		/* FIXME: we're sending the first error we encounter;
		 * maybe we should pick the worst... */
		rc = LDAP_NO_SUCH_OBJECT;
		for ( i = 0; i < mi->mi_ntargets; i++ ) {
			if ( META_IS_CANDIDATE( &candidates[ i ] )
				&& candidates[ i ].sr_err != LDAP_SUCCESS )
			{
				rc = candidates[ i ].sr_err;
				break;
			}
		}

		send_ldap_error( op, rs, rc, NULL );

		goto finish;
	}

	/* We pull apart the ber result, stuff it into a slapd entry, and
	 * let send_search_entry stuff it back into ber format. Slow & ugly,
	 * but this is necessary for version matching, and for ACL processing.
	 */

	if ( op->ors_tlimit != SLAP_NO_LIMIT ) {
		stoptime = op->o_time + op->ors_tlimit;
	}

	/*
	 * In case there are no candidates, no cycle takes place...
	 *
	 * FIXME: we might use a queue, to better balance the load 
	 * among the candidates
	 */
	for ( rc = 0; ncandidates > 0; ) {
		int	gotit = 0,
			doabandon = 0,
			alreadybound = ncandidates;

		/* check timeout */
		if ( timeout && lastres_time > 0
			&& ( slap_get_time() - lastres_time ) > timeout )
		{
			doabandon = 1;
			rs->sr_text = "Operation timed out";
			rc = rs->sr_err = op->o_protocol >= LDAP_VERSION3 ?
				LDAP_ADMINLIMIT_EXCEEDED : LDAP_OTHER;
			savepriv = op->o_private;
			op->o_private = (void *)i;
			send_ldap_result( op, rs );
			op->o_private = savepriv;
			goto finish;
		}

		/* check time limit */
		if ( op->ors_tlimit != SLAP_NO_LIMIT
				&& slap_get_time() > stoptime )
		{
			doabandon = 1;
			rc = rs->sr_err = LDAP_TIMELIMIT_EXCEEDED;
			savepriv = op->o_private;
			op->o_private = (void *)i;
			send_ldap_result( op, rs );
			op->o_private = savepriv;
			goto finish;
		}

		for ( i = 0; i < mi->mi_ntargets; i++ ) {
			meta_search_candidate_t	retcode = META_SEARCH_UNDEFINED;
			metasingleconn_t	*msc = &mc->mc_conns[ i ];
			LDAPMessage		*res = NULL, *msg;

			/* if msgid is invalid, don't ldap_result() */
			if ( candidates[ i ].sr_msgid == META_MSGID_IGNORE ) {
				continue;
			}

			/* if target still needs bind, retry */
			if ( candidates[ i ].sr_msgid == META_MSGID_NEED_BIND ) {
				/* initiate dobind */
				retcode = meta_search_dobind_init( op, rs, &mc, i, candidates );

				Debug( LDAP_DEBUG_TRACE, "%s <<< meta_search_dobind_init[%ld]=%d\n",
					op->o_log_prefix, i, retcode );

				switch ( retcode ) {
				case META_SEARCH_NEED_BIND:
					alreadybound--;
					/* fallthru */

				case META_SEARCH_BINDING:
					break;

				case META_SEARCH_ERR:
					candidates[ i ].sr_err = rs->sr_err;
					if ( META_BACK_ONERR_STOP( mi ) ) {
						savepriv = op->o_private;
						op->o_private = (void *)i;
						send_ldap_result( op, rs );
						op->o_private = savepriv;
						goto finish;
					}
					/* fallthru */

				case META_SEARCH_NOT_CANDIDATE:
					/*
					 * When no candidates are left,
					 * the outer cycle finishes
					 */
					candidates[ i ].sr_msgid = META_MSGID_IGNORE;
					assert( ncandidates > 0 );
					--ncandidates;
					break;

				case META_SEARCH_CANDIDATE:
					candidates[ i ].sr_msgid = META_MSGID_IGNORE;
					switch ( meta_back_search_start( op, rs, &dc, &mc, i, candidates ) )
					{
					case META_SEARCH_CANDIDATE:
						assert( candidates[ i ].sr_msgid >= 0 );
						break;

					case META_SEARCH_ERR:
						candidates[ i ].sr_err = rs->sr_err;
						if ( META_BACK_ONERR_STOP( mi ) ) {
							savepriv = op->o_private;
							op->o_private = (void *)i;
							send_ldap_result( op, rs );
							op->o_private = savepriv;
							goto finish;
						}
						/* fallthru */

					case META_SEARCH_NOT_CANDIDATE:
						/* means that meta_back_search_start()
						 * failed but onerr == continue */
						candidates[ i ].sr_msgid = META_MSGID_IGNORE;
						assert( ncandidates > 0 );
						--ncandidates;
						break;

					default:
						/* impossible */
						assert( 0 );
						break;
					}
					break;

				default:
					/* impossible */
					assert( 0 );
					break;
				}
				continue;
			}

			/* check for abandon */
			if ( op->o_abandon || LDAP_BACK_CONN_ABANDON( mc ) ) {
				break;
			}

#ifdef DEBUG_205
			if ( msc->msc_ld == NULL ) {
				char	buf[ SLAP_TEXT_BUFLEN ];

				ldap_pvt_thread_mutex_lock( &mi->mi_conninfo.lai_mutex );
				snprintf( buf, sizeof( buf ),
					"%s meta_back_search[%ld] mc=%p msgid=%d%s%s%s\n",
					op->o_log_prefix, (long)i, (void *)mc,
					candidates[ i ].sr_msgid,
					META_IS_BINDING( &candidates[ i ] ) ? " binding" : "",
					LDAP_BACK_CONN_BINDING( &mc->mc_conns[ i ] ) ? " connbinding" : "",
					META_BACK_CONN_CREATING( &mc->mc_conns[ i ] ) ? " conncreating" : "" );
				ldap_pvt_thread_mutex_unlock( &mi->mi_conninfo.lai_mutex );
					
				Debug( LDAP_DEBUG_ANY, "!!! %s\n", buf, 0, 0 );
			}
#endif /* DEBUG_205 */
			
			/*
			 * FIXME: handle time limit as well?
			 * Note that target servers are likely 
			 * to handle it, so at some time we'll
			 * get a LDAP_TIMELIMIT_EXCEEDED from
			 * one of them ...
			 */
			tv = save_tv;
			rc = ldap_result( msc->msc_ld, candidates[ i ].sr_msgid,
					LDAP_MSG_RECEIVED, &tv, &res );
			switch ( rc ) {
			case 0:
				/* FIXME: res should not need to be freed */
				assert( res == NULL );
				continue;

			case -1:
really_bad:;
				/* something REALLY bad happened! */
				if ( candidates[ i ].sr_type == REP_INTERMEDIATE ) {
					candidates[ i ].sr_type = REP_RESULT;

					if ( meta_back_retry( op, rs, &mc, i, LDAP_BACK_DONTSEND ) ) {
						candidates[ i ].sr_msgid = META_MSGID_IGNORE;
						switch ( meta_back_search_start( op, rs, &dc, &mc, i, candidates ) )
						{
							/* means that failed but onerr == continue */
						case META_SEARCH_NOT_CANDIDATE: