openldap/servers/slapd/back-meta/map.c

/* map.c - ldap backend mapping routines */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 1998-2008 The OpenLDAP Foundation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */
/* ACKNOWLEDGEMENTS:
 * This work was initially developed by the Howard Chu for inclusion
 * in OpenLDAP Software and subsequently enhanced by Pierangelo
 * Masarati.
 */
/* This is an altered version */
/*
 * Copyright 1999, Howard Chu, All rights reserved. <hyc@highlandsun.com>
 * 
 * Permission is granted to anyone to use this software for any purpose
 * on any computer system, and to alter it and redistribute it, subject
 * to the following restrictions:
 * 
 * 1. The author is not responsible for the consequences of use of this
 *    software, no matter how awful, even if they arise from flaws in it.
 * 
 * 2. The origin of this software must not be misrepresented, either by
 *    explicit claim or by omission.  Since few users ever read sources,
 *    credits should appear in the documentation.
 * 
 * 3. Altered versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.  Since few users
 *    ever read sources, credits should appear in the documentation.
 * 
 * 4. This notice may not be removed or altered.
 *
 *
 *
 * Copyright 2000, Pierangelo Masarati, All rights reserved. <ando@sys-net.it>
 * 
 * This software is being modified by Pierangelo Masarati.
 * The previously reported conditions apply to the modified code as well.
 * Changes in the original code are highlighted where required.
 * Credits for the original code go to the author, Howard Chu.
 */

#include "portable.h"

#include <stdio.h>

#include <ac/string.h>
#include <ac/socket.h>

#include "slap.h"
#include "lutil.h"
#include "../back-ldap/back-ldap.h"
#include "back-meta.h"

#undef ldap_debug	/* silence a warning in ldap-int.h */
#include "../../../libraries/libldap/ldap-int.h"

int
mapping_cmp ( const void *c1, const void *c2 )
{
	struct ldapmapping *map1 = (struct ldapmapping *)c1;
	struct ldapmapping *map2 = (struct ldapmapping *)c2;
	int rc = map1->src.bv_len - map2->src.bv_len;
	if (rc) return rc;
	return ( strcasecmp( map1->src.bv_val, map2->src.bv_val ) );
}

int
mapping_dup ( void *c1, void *c2 )
{
	struct ldapmapping *map1 = (struct ldapmapping *)c1;
	struct ldapmapping *map2 = (struct ldapmapping *)c2;

	return ( ( strcasecmp( map1->src.bv_val, map2->src.bv_val ) == 0 ) ? -1 : 0 );
}

void
ldap_back_map_init ( struct ldapmap *lm, struct ldapmapping **m )
{
	struct ldapmapping *mapping;

	assert( m != NULL );

	*m = NULL;

	mapping = (struct ldapmapping *)ch_calloc( 2, 
			sizeof( struct ldapmapping ) );
	if ( mapping == NULL ) {
		return;
	}

	ber_str2bv( "objectclass", STRLENOF("objectclass"), 1, &mapping[0].src);
	ber_dupbv( &mapping[0].dst, &mapping[0].src );
	mapping[1].src = mapping[0].src;
	mapping[1].dst = mapping[0].dst;

	avl_insert( &lm->map, (caddr_t)&mapping[0], 
			mapping_cmp, mapping_dup );
	avl_insert( &lm->remap, (caddr_t)&mapping[1], 
			mapping_cmp, mapping_dup );
	*m = mapping;
}

int
ldap_back_mapping ( struct ldapmap *map, struct berval *s, struct ldapmapping **m,
	int remap )
{
	Avlnode *tree;
	struct ldapmapping fmapping;

	assert( m != NULL );

	if ( remap == BACKLDAP_REMAP ) {
		tree = map->remap;

	} else {
		tree = map->map;
	}

	fmapping.src = *s;
	*m = (struct ldapmapping *)avl_find( tree, (caddr_t)&fmapping, mapping_cmp );
	if ( *m == NULL ) {
		return map->drop_missing;
	}

	return 0;
}

void
ldap_back_map ( struct ldapmap *map, struct berval *s, struct berval *bv,
	int remap )
{
	struct ldapmapping *mapping;

	/* map->map may be NULL when mapping is configured,
	 * but map->remap can't */
	if ( map->remap == NULL ) {
		*bv = *s;
		return;
	}

	BER_BVZERO( bv );
	( void )ldap_back_mapping( map, s, &mapping, remap );
	if ( mapping != NULL ) {
		if ( !BER_BVISNULL( &mapping->dst ) ) {
			*bv = mapping->dst;
		}
		return;
	}

	if ( !map->drop_missing ) {
		*bv = *s;
	}
}

int
ldap_back_map_attrs(
		struct ldapmap *at_map,
		AttributeName *an,
		int remap,
		char ***mapped_attrs
)
{
	int i, j;
	char **na;
	struct berval mapped;

	if ( an == NULL ) {
		*mapped_attrs = NULL;
		return LDAP_SUCCESS;
	}

	for ( i = 0; !BER_BVISNULL( &an[i].an_name ); i++ )
		/*  */ ;

	na = (char **)ch_calloc( i + 1, sizeof(char *) );
	if ( na == NULL ) {
		*mapped_attrs = NULL;
		return LDAP_NO_MEMORY;
	}

	for ( i = j = 0; !BER_BVISNULL( &an[i].an_name ); i++ ) {
		ldap_back_map( at_map, &an[i].an_name, &mapped, remap );
		if ( !BER_BVISNULL( &mapped ) && !BER_BVISEMPTY( &mapped ) ) {
			na[j++] = mapped.bv_val;
		}
	}
	if ( j == 0 && i != 0 ) {
		na[j++] = LDAP_NO_ATTRS;
	}
	na[j] = NULL;

	*mapped_attrs = na;
	return LDAP_SUCCESS;
}

int
map_attr_value(
		dncookie		*dc,
		AttributeDescription 	*ad,
		struct berval		*mapped_attr,
		struct berval		*value,
		struct berval		*mapped_value,
		int			remap )
{
	struct berval		vtmp;
	int			freeval = 0;

	ldap_back_map( &dc->target->mt_rwmap.rwm_at, &ad->ad_cname, mapped_attr, remap );
	if ( BER_BVISNULL( mapped_attr ) || BER_BVISEMPTY( mapped_attr ) ) {
#if 0
		/*
		 * FIXME: are we sure we need to search oc_map if at_map fails?
		 */
		ldap_back_map( &dc->target->mt_rwmap.rwm_oc, &ad->ad_cname, mapped_attr, remap );
		if ( BER_BVISNULL( mapped_attr ) || BER_BVISEMPTY( mapped_attr ) ) {
			*mapped_attr = ad->ad_cname;
		}
#endif
		if ( dc->target->mt_rwmap.rwm_at.drop_missing ) {
			return -1;
		}

		*mapped_attr = ad->ad_cname;
	}

	if ( value == NULL ) {
		return 0;
	}

	if ( ad->ad_type->sat_syntax == slap_schema.si_syn_distinguishedName )
	{
		dncookie fdc = *dc;

#ifdef ENABLE_REWRITE
		fdc.ctx = "searchFilterAttrDN";
#endif

		switch ( ldap_back_dn_massage( &fdc, value, &vtmp ) ) {
		case LDAP_SUCCESS:
			if ( vtmp.bv_val != value->bv_val ) {
				freeval = 1;
			}
			break;
		
		case LDAP_UNWILLING_TO_PERFORM:
			return -1;

		case LDAP_OTHER:
			return -1;
		}

	} else if ( ad->ad_type->sat_equality->smr_usage & SLAP_MR_MUTATION_NORMALIZER ) {
		if ( ad->ad_type->sat_equality->smr_normalize(
			(SLAP_MR_DENORMALIZE|SLAP_MR_VALUE_OF_ASSERTION_SYNTAX),
			NULL, NULL, value, &vtmp, NULL ) )
		{
			return -1;
		}
		freeval = 1;

	} else if ( ad == slap_schema.si_ad_objectClass || ad == slap_schema.si_ad_structuralObjectClass ) {
		ldap_back_map( &dc->target->mt_rwmap.rwm_oc, value, &vtmp, remap );
		if ( BER_BVISNULL( &vtmp ) || BER_BVISEMPTY( &vtmp ) ) {
			vtmp = *value;
		}
		
	} else {
		vtmp = *value;
	}

	filter_escape_value( &vtmp, mapped_value );

	if ( freeval ) {
		ber_memfree( vtmp.bv_val );
	}
	
	return 0;
}

static int
ldap_back_int_filter_map_rewrite(
		dncookie		*dc,
		Filter			*f,
		struct berval		*fstr,
		int			remap )
{
	int		i;
	Filter		*p;
	struct berval	atmp,
			vtmp,
			*tmp;
	static struct berval
			/* better than nothing... */
			ber_bvfalse = BER_BVC( "(!(objectClass=*))" ),
			ber_bvtf_false = BER_BVC( "(|)" ),
			/* better than nothing... */
			ber_bvtrue = BER_BVC( "(objectClass=*)" ),
			ber_bvtf_true = BER_BVC( "(&)" ),
#if 0
			/* no longer needed; preserved for completeness */
			ber_bvundefined = BER_BVC( "(?=undefined)" ),
#endif
			ber_bverror = BER_BVC( "(?=error)" ),
			ber_bvunknown = BER_BVC( "(?=unknown)" ),
			ber_bvnone = BER_BVC( "(?=none)" );
	ber_len_t	len;

	assert( fstr != NULL );
	BER_BVZERO( fstr );

	if ( f == NULL ) {
		ber_dupbv( fstr, &ber_bvnone );
		return LDAP_OTHER;
	}

	switch ( f->f_choice ) {
	case LDAP_FILTER_EQUALITY:
		if ( map_attr_value( dc, f->f_av_desc, &atmp,
					&f->f_av_value, &vtmp, remap ) )
		{
			goto computed;
		}

		fstr->bv_len = atmp.bv_len + vtmp.bv_len
			+ ( sizeof("(=)") - 1 );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=%s)",
			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );

		ber_memfree( vtmp.bv_val );
		break;

	case LDAP_FILTER_GE:
		if ( map_attr_value( dc, f->f_av_desc, &atmp,
					&f->f_av_value, &vtmp, remap ) )
		{
			goto computed;
		}

		fstr->bv_len = atmp.bv_len + vtmp.bv_len
			+ ( sizeof("(>=)") - 1 );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s>=%s)",
			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );

		ber_memfree( vtmp.bv_val );
		break;

	case LDAP_FILTER_LE:
		if ( map_attr_value( dc, f->f_av_desc, &atmp,
					&f->f_av_value, &vtmp, remap ) )
		{
			goto computed;
		}

		fstr->bv_len = atmp.bv_len + vtmp.bv_len
			+ ( sizeof("(<=)") - 1 );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s<=%s)",
			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );

		ber_memfree( vtmp.bv_val );
		break;

	case LDAP_FILTER_APPROX:
		if ( map_attr_value( dc, f->f_av_desc, &atmp,
					&f->f_av_value, &vtmp, remap ) )
		{
			goto computed;
		}

		fstr->bv_len = atmp.bv_len + vtmp.bv_len
			+ ( sizeof("(~=)") - 1 );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s~=%s)",
			atmp.bv_val, vtmp.bv_len ? vtmp.bv_val : "" );

		ber_memfree( vtmp.bv_val );
		break;

	case LDAP_FILTER_SUBSTRINGS:
		if ( map_attr_value( dc, f->f_sub_desc, &atmp,
					NULL, NULL, remap ) )
		{
			goto computed;
		}

		/* cannot be a DN ... */

		fstr->bv_len = atmp.bv_len + ( STRLENOF( "(=*)" ) );
		fstr->bv_val = malloc( fstr->bv_len + 128 ); /* FIXME: why 128 ? */

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
			atmp.bv_val );

		if ( !BER_BVISNULL( &f->f_sub_initial ) ) {
			len = fstr->bv_len;

			filter_escape_value( &f->f_sub_initial, &vtmp );

			fstr->bv_len += vtmp.bv_len;
			fstr->bv_val = ch_realloc( fstr->bv_val, fstr->bv_len + 1 );

			snprintf( &fstr->bv_val[len - 2], vtmp.bv_len + 3,
				/* "(attr=" */ "%s*)",
				vtmp.bv_len ? vtmp.bv_val : "" );

			ber_memfree( vtmp.bv_val );
		}

		if ( f->f_sub_any != NULL ) {
			for ( i = 0; !BER_BVISNULL( &f->f_sub_any[i] ); i++ ) {
				len = fstr->bv_len;
				filter_escape_value( &f->f_sub_any[i], &vtmp );

				fstr->bv_len += vtmp.bv_len + 1;
				fstr->bv_val = ch_realloc( fstr->bv_val, fstr->bv_len + 1 );

				snprintf( &fstr->bv_val[len - 1], vtmp.bv_len + 3,
					/* "(attr=[init]*[any*]" */ "%s*)",
					vtmp.bv_len ? vtmp.bv_val : "" );
				ber_memfree( vtmp.bv_val );
			}
		}

		if ( !BER_BVISNULL( &f->f_sub_final ) ) {
			len = fstr->bv_len;

			filter_escape_value( &f->f_sub_final, &vtmp );

			fstr->bv_len += vtmp.bv_len;
			fstr->bv_val = ch_realloc( fstr->bv_val, fstr->bv_len + 1 );

			snprintf( &fstr->bv_val[len - 1], vtmp.bv_len + 3,
				/* "(attr=[init*][any*]" */ "%s)",
				vtmp.bv_len ? vtmp.bv_val : "" );

			ber_memfree( vtmp.bv_val );
		}

		break;

	case LDAP_FILTER_PRESENT:
		if ( map_attr_value( dc, f->f_desc, &atmp,
					NULL, NULL, remap ) )
		{
			goto computed;
		}

		fstr->bv_len = atmp.bv_len + ( STRLENOF( "(=*)" ) );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s=*)",
			atmp.bv_val );
		break;

	case LDAP_FILTER_AND:
	case LDAP_FILTER_OR:
	case LDAP_FILTER_NOT:
		fstr->bv_len = STRLENOF( "(%)" );
		fstr->bv_val = malloc( fstr->bv_len + 128 );	/* FIXME: why 128? */

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%c)",
			f->f_choice == LDAP_FILTER_AND ? '&' :
			f->f_choice == LDAP_FILTER_OR ? '|' : '!' );

		for ( p = f->f_list; p != NULL; p = p->f_next ) {
			int	rc;

			len = fstr->bv_len;

			rc = ldap_back_int_filter_map_rewrite( dc, p, &vtmp, remap );
			if ( rc != LDAP_SUCCESS ) {
				return rc;
			}
			
			fstr->bv_len += vtmp.bv_len;
			fstr->bv_val = ch_realloc( fstr->bv_val, fstr->bv_len + 1 );

			snprintf( &fstr->bv_val[len-1], vtmp.bv_len + 2, 
				/*"("*/ "%s)", vtmp.bv_len ? vtmp.bv_val : "" );

			ch_free( vtmp.bv_val );
		}

		break;

	case LDAP_FILTER_EXT:
		if ( f->f_mr_desc ) {
			if ( map_attr_value( dc, f->f_mr_desc, &atmp,
						&f->f_mr_value, &vtmp, remap ) )
			{
				goto computed;
			}

		} else {
			BER_BVSTR( &atmp, "" );
			filter_escape_value( &f->f_mr_value, &vtmp );
		}

		/* FIXME: cleanup (less ?: operators...) */
		fstr->bv_len = atmp.bv_len +
			( f->f_mr_dnattrs ? STRLENOF( ":dn" ) : 0 ) +
			( !BER_BVISEMPTY( &f->f_mr_rule_text ) ? f->f_mr_rule_text.bv_len + 1 : 0 ) +
			vtmp.bv_len + ( STRLENOF( "(:=)" ) );
		fstr->bv_val = malloc( fstr->bv_len + 1 );

		snprintf( fstr->bv_val, fstr->bv_len + 1, "(%s%s%s%s:=%s)",
			atmp.bv_val,
			f->f_mr_dnattrs ? ":dn" : "",
			!BER_BVISEMPTY( &f->f_mr_rule_text ) ? ":" : "",
			!BER_BVISEMPTY( &f->f_mr_rule_text ) ? f->f_mr_rule_text.bv_val : "",
			vtmp.bv_len ? vtmp.bv_val : "" );
		ber_memfree( vtmp.bv_val );
		break;

	case SLAPD_FILTER_COMPUTED:
		switch ( f->f_result ) {
		case LDAP_COMPARE_FALSE:
		/* FIXME: treat UNDEFINED as FALSE */
		case SLAPD_COMPARE_UNDEFINED:
computed:;
			if ( META_BACK_TGT_T_F( dc->target ) ) {
				tmp = &ber_bvtf_false;
				break;
			}
			tmp = &ber_bvfalse;
			break;

		case LDAP_COMPARE_TRUE:
			if ( META_BACK_TGT_T_F( dc->target ) ) {
				tmp = &ber_bvtf_true;
				break;
			}

			tmp = &ber_bvtrue;
			break;

		default:
			tmp = &ber_bverror;
			break;
		}

		ber_dupbv( fstr, tmp );
		break;

	default:
		ber_dupbv( fstr, &ber_bvunknown );
		break;
	}

	return 0;
}

int
ldap_back_filter_map_rewrite(
		dncookie		*dc,
		Filter			*f,
		struct berval		*fstr,
		int			remap )
{
	int		rc;
	dncookie	fdc;
	struct berval	ftmp;
	static char	*dmy = "";

	rc = ldap_back_int_filter_map_rewrite( dc, f, fstr, remap );

#ifdef ENABLE_REWRITE
	if ( rc != LDAP_SUCCESS ) {
		return rc;
	}

	fdc = *dc;
	ftmp = *fstr;

	fdc.ctx = "searchFilter";
	
	switch ( rewrite_session( fdc.target->mt_rwmap.rwm_rw, fdc.ctx,
				( !BER_BVISEMPTY( &ftmp ) ? ftmp.bv_val : dmy ),
				fdc.conn, &fstr->bv_val ) )
	{
	case REWRITE_REGEXEC_OK:
		if ( !BER_BVISNULL( fstr ) ) {
			fstr->bv_len = strlen( fstr->bv_val );

		} else {
			*fstr = ftmp;
		}
		Debug( LDAP_DEBUG_ARGS,
			"[rw] %s: \"%s\" -> \"%s\"\n",
			fdc.ctx, BER_BVISNULL( &ftmp ) ? "" : ftmp.bv_val,
			BER_BVISNULL( fstr ) ? "" : fstr->bv_val );		
		rc = LDAP_SUCCESS;
		break;
 		
 	case REWRITE_REGEXEC_UNWILLING:
		if ( fdc.rs ) {
			fdc.rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
			fdc.rs->sr_text = "Operation not allowed";
		}
		rc = LDAP_UNWILLING_TO_PERFORM;
		break;
	       	
	case REWRITE_REGEXEC_ERR:
		if ( fdc.rs ) {
			fdc.rs->sr_err = LDAP_OTHER;
			fdc.rs->sr_text = "Rewrite error";
		}
		rc = LDAP_OTHER;
		break;
	}

	if ( fstr->bv_val == dmy ) {
		BER_BVZERO( fstr );
	}
#endif /* ENABLE_REWRITE */

	return rc;
}

int
ldap_back_referral_result_rewrite(
	dncookie		*dc,
	BerVarray		a_vals
)
{
	int		i, last;

	assert( dc != NULL );
	assert( a_vals != NULL );

	for ( last = 0; !BER_BVISNULL( &a_vals[ last ] ); last++ )
		;
	last--;

	for ( i = 0; !BER_BVISNULL( &a_vals[ i ] ); i++ ) {
		struct berval	dn,
				olddn = BER_BVNULL;
		int		rc;
		LDAPURLDesc	*ludp;

		rc = ldap_url_parse( a_vals[ i ].bv_val, &ludp );
		if ( rc != LDAP_URL_SUCCESS ) {
			/* leave attr untouched if massage failed */
			continue;
		}

		/* FIXME: URLs like "ldap:///dc=suffix" if passed
		 * thru ldap_url_parse() and ldap_url_desc2str()
		 * get rewritten as "ldap:///dc=suffix??base";
		 * we don't want this to occur... */
		if ( ludp->lud_scope == LDAP_SCOPE_BASE ) {
			ludp->lud_scope = LDAP_SCOPE_DEFAULT;
		}

		ber_str2bv( ludp->lud_dn, 0, 0, &olddn );
		
		rc = ldap_back_dn_massage( dc, &olddn, &dn );
		switch ( rc ) {
		case LDAP_UNWILLING_TO_PERFORM:
			/*
			 * FIXME: need to check if it may be considered 
			 * legal to trim values when adding/modifying;
			 * it should be when searching (e.g. ACLs).
			 */
			LBER_FREE( a_vals[ i ].bv_val );
			if ( last > i ) {
				a_vals[ i ] = a_vals[ last ];
			}
			BER_BVZERO( &a_vals[ last ] );
			last--;
			i--;
			break;

		default:
			/* leave attr untouched if massage failed */
			if ( !BER_BVISNULL( &dn ) && olddn.bv_val != dn.bv_val )
			{
				char	*newurl;

				ludp->lud_dn = dn.bv_val;
				newurl = ldap_url_desc2str( ludp );
				free( dn.bv_val );
				if ( newurl == NULL ) {
					/* FIXME: leave attr untouched
					 * even if ldap_url_desc2str failed...
					 */
					break;
				}

				LBER_FREE( a_vals[ i ].bv_val );
				ber_str2bv( newurl, 0, 1, &a_vals[ i ] );
				LDAP_FREE( newurl );
				ludp->lud_dn = olddn.bv_val;
			}
			break;
		}

		ldap_free_urldesc( ludp );
	}

	return 0;
}

/*
 * I don't like this much, but we need two different
 * functions because different heap managers may be
 * in use in back-ldap/meta to reduce the amount of
 * calls to malloc routines, and some of the free()
 * routines may be macros with args
 */
int
ldap_dnattr_rewrite(
	dncookie		*dc,
	BerVarray		a_vals
)
{
	struct berval	bv;
	int		i, last;

	assert( a_vals != NULL );

	for ( last = 0; !BER_BVISNULL( &a_vals[last] ); last++ )
		;
	last--;

	for ( i = 0; !BER_BVISNULL( &a_vals[i] ); i++ ) {
		switch ( ldap_back_dn_massage( dc, &a_vals[i], &bv ) ) {
		case LDAP_UNWILLING_TO_PERFORM:
			/*
			 * FIXME: need to check if it may be considered 
			 * legal to trim values when adding/modifying;
			 * it should be when searching (e.g. ACLs).
			 */
			ch_free( a_vals[i].bv_val );
			if ( last > i ) {
				a_vals[i] = a_vals[last];
			}
			BER_BVZERO( &a_vals[last] );
			last--;
			break;

		default:
			/* leave attr untouched if massage failed */
			if ( !BER_BVISNULL( &bv ) && bv.bv_val != a_vals[i].bv_val ) {
				ch_free( a_vals[i].bv_val );
				a_vals[i] = bv;
			}
			break;
		}
	}
	
	return 0;
}

int
ldap_dnattr_result_rewrite(
	dncookie		*dc,
	BerVarray		a_vals
)
{
	struct berval	bv;
	int		i, last;

	assert( a_vals != NULL );

	for ( last = 0; !BER_BVISNULL( &a_vals[last] ); last++ )
		;
	last--;

	for ( i = 0; !BER_BVISNULL( &a_vals[i] ); i++ ) {
		switch ( ldap_back_dn_massage( dc, &a_vals[i], &bv ) ) {
		case LDAP_UNWILLING_TO_PERFORM:
			/*
			 * FIXME: need to check if it may be considered 
			 * legal to trim values when adding/modifying;
			 * it should be when searching (e.g. ACLs).
			 */
			LBER_FREE( a_vals[i].bv_val );
			if ( last > i ) {
				a_vals[i] = a_vals[last];
			}
			BER_BVZERO( &a_vals[last] );
			last--;
			break;

		default:
			/* leave attr untouched if massage failed */
			if ( !BER_BVISNULL( &bv ) && a_vals[i].bv_val != bv.bv_val ) {
				LBER_FREE( a_vals[i].bv_val );
				a_vals[i] = bv;
			}
			break;
		}
	}

	return 0;
}