]> git.sur5r.net Git - openldap/blobdiff - servers/slapd/overlays/syncprov.c
ITS#5322 don't try to free a NULL locker
[openldap] / servers / slapd / overlays / syncprov.c
index c7ad1417b88d4c3d7af1bb5f2ab30115a2105c10..ad8b9bb329e0b507e54f8dbaf4833156c4058aeb 100644 (file)
@@ -2,7 +2,7 @@
 /* syncprov.c - syncrepl provider */
 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
  *
- * Copyright 2004-2007 The OpenLDAP Foundation.
+ * Copyright 2004-2008 The OpenLDAP Foundation.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -59,6 +59,7 @@ typedef struct syncops {
        ID              s_eid;          /* entryID of search base */
        Operation       *s_op;          /* search op */
        int             s_rid;
+       int             s_sid;
        struct berval s_filterstr;
        int             s_flags;        /* search status */
 #define        PS_IS_REFRESHING        0x01
@@ -130,7 +131,7 @@ typedef struct syncprov_info_t {
        time_t  si_chklast;     /* time of last checkpoint */
        Avlnode *si_mods;       /* entries being modified */
        sessionlog      *si_logs;
-       ldap_pvt_thread_mutex_t si_csn_mutex;
+       ldap_pvt_thread_rdwr_t  si_csn_rwlock;
        ldap_pvt_thread_mutex_t si_ops_mutex;
        ldap_pvt_thread_mutex_t si_mods_mutex;
 } syncprov_info_t;
@@ -403,6 +404,7 @@ syncprov_findbase( Operation *op, fbase_cookie *fc )
                slap_callback cb = {0};
                Operation fop;
                SlapReply frs = { REP_RESULT };
+               BackendInfo *bi;
                int rc;
 
                fc->fss->s_flags ^= PS_FIND_BASE;
@@ -414,6 +416,7 @@ syncprov_findbase( Operation *op, fbase_cookie *fc )
                fop.o_bd = op->o_bd;
                fop.o_time = op->o_time;
                fop.o_tincr = op->o_tincr;
+               bi = op->o_bd->bd_info;
 
                cb.sc_response = findbase_cb;
                cb.sc_private = fc;
@@ -431,9 +434,8 @@ syncprov_findbase( Operation *op, fbase_cookie *fc )
                fop.ors_filter = &generic_filter;
                fop.ors_filterstr = generic_filterstr;
 
-               fop.o_bd->bd_info = on->on_info->oi_orig;
-               rc = fop.o_bd->be_search( &fop, &frs );
-               fop.o_bd->bd_info = (BackendInfo *)on;
+               rc = overlay_op_walk( &fop, &frs, op_search, on->on_info, on );
+               op->o_bd->bd_info = bi;
        } else {
                ldap_pvt_thread_mutex_unlock( &fc->fss->s_mutex );
                fc->fbase = 1;
@@ -583,11 +585,7 @@ syncprov_findcsn( Operation *op, find_csn_t mode )
        char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
        struct berval maxcsn;
        Filter cf;
-#ifdef LDAP_COMP_MATCH
-       AttributeAssertion eq = { NULL, BER_BVNULL, NULL };
-#else
-       AttributeAssertion eq = { NULL, BER_BVNULL };
-#endif
+       AttributeAssertion eq = ATTRIBUTEASSERTION_INIT;
        fpres_cookie pcookie;
        sync_control *srs = NULL;
        struct slap_limits_set fc_limits;
@@ -626,8 +624,11 @@ again:
                                maxid = i;
                        }
                }
-               fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN>=%s)",
-                       cf.f_av_value.bv_val );
+               fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
+                       "(entryCSN>=%s)", cf.f_av_value.bv_val );
+               if ( fop.ors_filterstr.bv_len < 0 || fop.ors_filterstr.bv_len >= sizeof( buf ) ) {
+                       return LDAP_OTHER;
+               }
                fop.ors_attrsonly = 0;
                fop.ors_attrs = csn_anlist;
                fop.ors_slimit = SLAP_NO_LIMIT;
@@ -651,15 +652,19 @@ again:
                /* Look for exact match the first time */
                if ( findcsn_retry ) {
                        cf.f_choice = LDAP_FILTER_EQUALITY;
-                       fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN=%s)",
-                               cf.f_av_value.bv_val );
+                       fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
+                               "(entryCSN=%s)", cf.f_av_value.bv_val );
                /* On retry, look for <= */
                } else {
                        cf.f_choice = LDAP_FILTER_LE;
                        fop.ors_limit = &fc_limits;
+                       memset( &fc_limits, 0, sizeof( fc_limits ));
                        fc_limits.lms_s_unchecked = 1;
-                       fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN<=%s)",
-                               cf.f_av_value.bv_val );
+                       fop.ors_filterstr.bv_len = snprintf( buf, sizeof( buf ),
+                               "(entryCSN<=%s)", cf.f_av_value.bv_val );
+               }
+               if ( fop.ors_filterstr.bv_len < 0 || fop.ors_filterstr.bv_len >= sizeof( buf ) ) {
+                       return LDAP_OTHER;
                }
                fop.ors_attrsonly = 1;
                fop.ors_attrs = slap_anlist_no_attrs;
@@ -769,7 +774,9 @@ syncprov_sendresp( Operation *op, opcookie *opc, syncops *so,
        ctrls[1] = NULL;
        csns[0] = opc->sctxcsn;
        BER_BVZERO( &csns[1] );
-       slap_compose_sync_cookie( op, &cookie, csns, so->s_rid );
+       slap_compose_sync_cookie( op, &cookie, csns, so->s_rid, so->s_sid );
+
+       Debug( LDAP_DEBUG_SYNC, "syncprov_sendresp: cookie=%s\n", cookie.bv_val, 0, 0 );
 
        e_uuid.e_attrs = &a_uuid;
        a_uuid.a_desc = slap_schema.si_ad_entryUUID;
@@ -838,7 +845,6 @@ syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
        int rc = 0;
 
        opc.son = on;
-       op->o_bd->bd_info = (BackendInfo *)on->on_info;
 
        for (;;) {
                ldap_pvt_thread_mutex_lock( &so->s_mutex );
@@ -860,7 +866,7 @@ syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
                e = NULL;
 
                if ( sr->s_mode != LDAP_SYNC_DELETE ) {
-                       rc = be_entry_get_rw( op, &opc.sndn, NULL, NULL, 0, &e );
+                       rc = overlay_entry_get_ov( op, &opc.sndn, NULL, NULL, 0, &e, on );
                        if ( rc ) {
                                Debug( LDAP_DEBUG_SYNC, "syncprov_qplay: failed to get %s, "
                                        "error (%d), ignoring...\n", opc.sndn.bv_val, rc, 0 );
@@ -872,7 +878,7 @@ syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
                rc = syncprov_sendresp( op, &opc, so, &e, sr->s_mode );
 
                if ( e ) {
-                       be_entry_release_rw( op, e, 0 );
+                       overlay_entry_release_ov( op, e, 0, on );
                }
 
                ch_free( sr );
@@ -880,7 +886,6 @@ syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
                if ( rc )
                        break;
        }
-       op->o_bd->bd_info = (BackendInfo *)on;
        return rc;
 }
 
@@ -896,15 +901,15 @@ syncprov_qtask( void *ctx, void *arg )
        BackendDB be;
        int rc;
 
-       op = (Operation *) &opbuf;
+       op = &opbuf.ob_op;
        *op = *so->s_op;
-       op->o_hdr = (Opheader *)(op+1);
-       op->o_controls = (void **)(op->o_hdr+1);
-       memset( op->o_controls, 0, SLAP_MAX_CIDS * sizeof(void *));
+       op->o_hdr = &opbuf.ob_hdr;
+       op->o_controls = opbuf.ob_controls;
+       memset( op->o_controls, 0, sizeof(opbuf.ob_controls) );
 
        *op->o_hdr = *so->s_op->o_hdr;
 
-       op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx);
+       op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx, 1);
        op->o_tmpmfuncs = &slap_sl_mfuncs;
        op->o_threadctx = ctx;
 
@@ -977,9 +982,18 @@ static int
 syncprov_qresp( opcookie *opc, syncops *so, int mode )
 {
        syncres *sr;
+       int sid, srsize;
+
+       /* Don't send changes back to their originator */
+       sid = slap_parse_csn_sid( &opc->sctxcsn );
+       if ( sid >= 0 && sid == so->s_sid )
+               return LDAP_SUCCESS;
 
-       sr = ch_malloc(sizeof(syncres) + opc->suuid.bv_len + 1 +
-               opc->sdn.bv_len + 1 + opc->sndn.bv_len + 1 + opc->sctxcsn.bv_len + 1 );
+       srsize = sizeof(syncres) + opc->suuid.bv_len + 1 +
+               opc->sdn.bv_len + 1 + opc->sndn.bv_len + 1;
+       if ( opc->sctxcsn.bv_len )
+               srsize += opc->sctxcsn.bv_len + 1;
+       sr = ch_malloc( srsize );
        sr->s_next = NULL;
        sr->s_dn.bv_val = (char *)(sr + 1);
        sr->s_dn.bv_len = opc->sdn.bv_len;
@@ -992,9 +1006,13 @@ syncprov_qresp( opcookie *opc, syncops *so, int mode )
                 opc->sndn.bv_val ) + 1;
        sr->s_uuid.bv_len = opc->suuid.bv_len;
        AC_MEMCPY( sr->s_uuid.bv_val, opc->suuid.bv_val, opc->suuid.bv_len );
-       sr->s_csn.bv_val = sr->s_uuid.bv_val + sr->s_uuid.bv_len + 1;
+       if ( opc->sctxcsn.bv_len ) {
+               sr->s_csn.bv_val = sr->s_uuid.bv_val + sr->s_uuid.bv_len + 1;
+               strcpy( sr->s_csn.bv_val, opc->sctxcsn.bv_val );
+       } else {
+               sr->s_csn.bv_val = NULL;
+       }
        sr->s_csn.bv_len = opc->sctxcsn.bv_len;
-       strcpy( sr->s_csn.bv_val, opc->sctxcsn.bv_val );
 
        ldap_pvt_thread_mutex_lock( &so->s_mutex );
        if ( !so->s_res ) {
@@ -1024,7 +1042,7 @@ syncprov_drop_psearch( syncops *so, int lock )
                        ldap_pvt_thread_mutex_lock( &so->s_op->o_conn->c_mutex );
                so->s_op->o_conn->c_n_ops_executing--;
                so->s_op->o_conn->c_n_ops_completed++;
-               LDAP_STAILQ_REMOVE( &so->s_op->o_conn->c_ops, so->s_op, slap_op,
+               LDAP_STAILQ_REMOVE( &so->s_op->o_conn->c_ops, so->s_op, Operation,
                        o_next );
                if ( lock )
                        ldap_pvt_thread_mutex_unlock( &so->s_op->o_conn->c_mutex );
@@ -1091,7 +1109,7 @@ syncprov_matchops( Operation *op, opcookie *opc, int saveit )
 
        fbase_cookie fc;
        syncops *ss, *sprev, *snext;
-       Entry *e;
+       Entry *e = NULL;
        Attribute *a;
        int rc;
        struct berval newdn;
@@ -1113,15 +1131,13 @@ syncprov_matchops( Operation *op, opcookie *opc, int saveit )
                        db = *op->o_bd;
                        op->o_bd = &db;
                }
-               op->o_bd->bd_info = (BackendInfo *)on->on_info;
-               rc = be_entry_get_rw( op, fc.fdn, NULL, NULL, 0, &e );
+               rc = overlay_entry_get_ov( op, fc.fdn, NULL, NULL, 0, &e, on );
                /* If we're sending responses now, make a copy and unlock the DB */
                if ( e && !saveit ) {
                        Entry *e2 = entry_dup( e );
-                       be_entry_release_rw( op, e, 0 );
+                       overlay_entry_release_ov( op, e, 0, on );
                        e = e2;
                }
-               op->o_bd->bd_info = (BackendInfo *)on;
                if ( rc ) {
                        op->o_bd = b0;
                        return;
@@ -1216,9 +1232,11 @@ syncprov_matchops( Operation *op, opcookie *opc, int saveit )
        ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
 
        if ( op->o_tag != LDAP_REQ_ADD && e ) {
-               op->o_bd->bd_info = (BackendInfo *)on->on_info;
-               be_entry_release_rw( op, e, 0 );
-               op->o_bd->bd_info = (BackendInfo *)on;
+               if ( !SLAP_ISOVERLAY( op->o_bd )) {
+                       op->o_bd = &db;
+               }
+               overlay_entry_release_ov( op, e, 0, on );
+               op->o_bd = b0;
        }
        if ( freefdn ) {
                op->o_tmpfree( fc.fdn->bv_val, op->o_tmpmemctx );
@@ -1278,12 +1296,13 @@ syncprov_op_cleanup( Operation *op, SlapReply *rs )
 static void
 syncprov_checkpoint( Operation *op, SlapReply *rs, slap_overinst *on )
 {
-    syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
+       syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
        Modifications mod;
        Operation opm;
        SlapReply rsm = { 0 };
        slap_callback cb = {0};
 
+       mod.sml_numvals = si->si_numcsns;
        mod.sml_values = si->si_ctxcsn;
        mod.sml_nvalues = NULL;
        mod.sml_desc = slap_schema.si_ad_contextCSN;
@@ -1301,10 +1320,12 @@ syncprov_checkpoint( Operation *op, SlapReply *rs, slap_overinst *on )
        opm.o_req_ndn = op->o_bd->be_nsuffix[0];
        opm.o_bd->bd_info = on->on_info->oi_orig;
        opm.o_managedsait = SLAP_CONTROL_NONCRITICAL;
+       opm.o_no_schema_check = 1;
        opm.o_bd->be_modify( &opm, &rsm );
        if ( mod.sml_next != NULL ) {
                slap_mods_free( mod.sml_next, 1 );
        }
+       opm.orm_no_opattrs = 0;
 }
 
 static void
@@ -1474,11 +1495,7 @@ syncprov_playlog( Operation *op, SlapReply *rs, sessionlog *sl,
                SlapReply frs = { REP_RESULT };
                int rc;
                Filter mf, af;
-#ifdef LDAP_COMP_MATCH
-               AttributeAssertion eq = { NULL, BER_BVNULL, NULL };
-#else
-               AttributeAssertion eq;
-#endif
+               AttributeAssertion eq = ATTRIBUTEASSERTION_INIT;
                slap_callback cb = {0};
 
                fop = *op;
@@ -1523,7 +1540,11 @@ syncprov_playlog( Operation *op, SlapReply *rs, sessionlog *sl,
        if ( ndel ) {
                struct berval cookie;
 
-               slap_compose_sync_cookie( op, &cookie, delcsn, srs->sr_state.rid );
+               slap_compose_sync_cookie( op, &cookie, delcsn, srs->sr_state.rid,
+                       srs->sr_state.sid );
+
+               Debug( LDAP_DEBUG_SYNC, "syncprov_playlog: cookie=%s\n", cookie.bv_val, 0, 0 );
+
                uuids[ndel].bv_val = NULL;
                syncprov_sendinfo( op, rs, LDAP_TAG_SYNC_ID_SET, &cookie, 0, uuids, 1 );
                op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
@@ -1543,11 +1564,11 @@ syncprov_op_response( Operation *op, SlapReply *rs )
        {
                struct berval maxcsn = BER_BVNULL;
                char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
-               int do_check = 0;
+               int do_check = 0, have_psearches;
 
                /* Update our context CSN */
                cbuf[0] = '\0';
-               ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+               ldap_pvt_thread_rdwr_wlock( &si->si_csn_rwlock );
                slap_get_commit_csn( op, &maxcsn );
                if ( !BER_BVISNULL( &maxcsn ) ) {
                        int i, sid;
@@ -1574,7 +1595,7 @@ syncprov_op_response( Operation *op, SlapReply *rs )
                /* Don't do any processing for consumer contextCSN updates */
                if ( SLAP_SYNC_SHADOW( op->o_bd ) && 
                        op->o_msgid == SLAP_SYNC_UPDATE_MSGID ) {
-                       ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+                       ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
                        return SLAP_CB_CONTINUE;
                }
 
@@ -1586,21 +1607,30 @@ syncprov_op_response( Operation *op, SlapReply *rs )
                        }
                        if ( si->si_chktime &&
                                (op->o_time - si->si_chklast >= si->si_chktime )) {
-                               do_check = 1;
-                               si->si_chklast = op->o_time;
+                               if ( si->si_chklast ) {
+                                       do_check = 1;
+                                       si->si_chklast = op->o_time;
+                               } else {
+                                       si->si_chklast = 1;
+                               }
                        }
                }
-               ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
-
-               opc->sctxcsn.bv_len = maxcsn.bv_len;
-               opc->sctxcsn.bv_val = cbuf;
+               ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
 
                if ( do_check ) {
+                       ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
                        syncprov_checkpoint( op, rs, on );
+                       ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
                }
 
+               opc->sctxcsn.bv_len = maxcsn.bv_len;
+               opc->sctxcsn.bv_val = cbuf;
+
                /* Handle any persistent searches */
-               if ( si->si_ops ) {
+               ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
+               have_psearches = ( si->si_ops != NULL );
+               ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
+               if ( have_psearches ) {
                        switch(op->o_tag) {
                        case LDAP_REQ_ADD:
                        case LDAP_REQ_MODIFY:
@@ -1653,7 +1683,7 @@ syncprov_op_compare( Operation *op, SlapReply *rs )
 
                a.a_desc = slap_schema.si_ad_contextCSN;
 
-               ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+               ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
 
                a.a_vals = si->si_ctxcsn;
                a.a_nvals = a.a_vals;
@@ -1675,17 +1705,17 @@ syncprov_op_compare( Operation *op, SlapReply *rs )
 
                rs->sr_err = LDAP_COMPARE_FALSE;
 
-               if ( value_find_ex( op->oq_compare.rs_ava->aa_desc,
+               if ( attr_valfind( &a,
                        SLAP_MR_ATTRIBUTE_VALUE_NORMALIZED_MATCH |
                                SLAP_MR_ASSERTED_VALUE_NORMALIZED_MATCH,
-                               a.a_nvals, &op->oq_compare.rs_ava->aa_value, op->o_tmpmemctx ) == 0 )
+                               &op->oq_compare.rs_ava->aa_value, NULL, op->o_tmpmemctx ) == 0 )
                {
                        rs->sr_err = LDAP_COMPARE_TRUE;
                }
 
 return_results:;
 
-               ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+               ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
 
                send_ldap_result( op, rs );
 
@@ -1703,12 +1733,19 @@ syncprov_op_mod( Operation *op, SlapReply *rs )
 {
        slap_overinst           *on = (slap_overinst *)op->o_bd->bd_info;
        syncprov_info_t         *si = on->on_bi.bi_private;
+       slap_callback *cb;
+       opcookie *opc;
+       int have_psearches, cbsize;
 
-       slap_callback *cb = op->o_tmpcalloc(1, sizeof(slap_callback)+
-               sizeof(opcookie) +
-               (si->si_ops ? sizeof(modinst) : 0 ),
-               op->o_tmpmemctx);
-       opcookie *opc = (opcookie *)(cb+1);
+       ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
+       have_psearches = ( si->si_ops != NULL );
+       ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
+
+       cbsize = sizeof(slap_callback) + sizeof(opcookie) +
+               (have_psearches ? sizeof(modinst) : 0 );
+
+       cb = op->o_tmpcalloc(1, cbsize, op->o_tmpmemctx);
+       opc = (opcookie *)(cb+1);
        opc->son = on;
        cb->sc_response = syncprov_op_response;
        cb->sc_cleanup = syncprov_op_cleanup;
@@ -1719,7 +1756,7 @@ syncprov_op_mod( Operation *op, SlapReply *rs )
        /* If there are active persistent searches, lock this operation.
         * See seqmod.c for the locking logic on its own.
         */
-       if ( si->si_ops ) {
+       if ( have_psearches ) {
                modtarget *mt, mtdummy;
                modinst *mi;
 
@@ -1766,7 +1803,7 @@ syncprov_op_mod( Operation *op, SlapReply *rs )
                }
        }
 
-       if (( si->si_ops || si->si_logs ) && op->o_tag != LDAP_REQ_ADD )
+       if (( have_psearches || si->si_logs ) && op->o_tag != LDAP_REQ_ADD )
                syncprov_matchops( op, opc, 1 );
 
        return SLAP_CB_CONTINUE;
@@ -1787,7 +1824,9 @@ typedef struct searchstate {
        BerVarray ss_ctxcsn;
        int *ss_sids;
        int ss_numcsns;
-       int ss_present;
+#define        SS_PRESENT      0x01
+#define        SS_CHANGED      0x02
+       int ss_flags;
 } searchstate;
 
 static int
@@ -1801,9 +1840,17 @@ syncprov_search_cleanup( Operation *op, SlapReply *rs )
        return 0;
 }
 
+typedef struct SyncOperationBuffer {
+       Operation               sob_op;
+       Opheader                sob_hdr;
+       AttributeName   sob_extra;      /* not always present */
+       /* Further data allocated here */
+} SyncOperationBuffer;
+
 static void
 syncprov_detach_op( Operation *op, syncops *so, slap_overinst *on )
 {
+       SyncOperationBuffer *sopbuf2;
        Operation *op2;
        int i, alen = 0;
        size_t size;
@@ -1815,14 +1862,15 @@ syncprov_detach_op( Operation *op, syncops *so, slap_overinst *on )
                alen += op->ors_attrs[i].an_name.bv_len + 1;
        }
        /* Make a new copy of the operation */
-       size = sizeof(Operation) + sizeof(Opheader) +
+       size = offsetof( SyncOperationBuffer, sob_extra ) +
                (i ? ( (i+1) * sizeof(AttributeName) + alen) : 0) +
                op->o_req_dn.bv_len + 1 +
                op->o_req_ndn.bv_len + 1 +
                op->o_ndn.bv_len + 1 +
                so->s_filterstr.bv_len + 1;
-       op2 = (Operation *)ch_calloc( 1, size );
-       op2->o_hdr = (Opheader *)(op2+1);
+       sopbuf2 = ch_calloc( 1, size );
+       op2 = &sopbuf2->sob_op;
+       op2->o_hdr = &sopbuf2->sob_hdr;
 
        /* Copy the fields we care about explicitly, leave the rest alone */
        *op2->o_hdr = *op->o_hdr;
@@ -1832,18 +1880,18 @@ syncprov_detach_op( Operation *op, syncops *so, slap_overinst *on )
        op2->o_request = op->o_request;
        op2->o_private = on;
 
+       ptr = (char *) sopbuf2 + offsetof( SyncOperationBuffer, sob_extra );
        if ( i ) {
-               op2->ors_attrs = (AttributeName *)(op2->o_hdr + 1);
-               ptr = (char *)(op2->ors_attrs+i+1);
+               op2->ors_attrs = (AttributeName *) ptr;
+               ptr = (char *) &op2->ors_attrs[i+1];
                for (i=0; !BER_BVISNULL( &op->ors_attrs[i].an_name ); i++) {
                        op2->ors_attrs[i] = op->ors_attrs[i];
                        op2->ors_attrs[i].an_name.bv_val = ptr;
                        ptr = lutil_strcopy( ptr, op->ors_attrs[i].an_name.bv_val ) + 1;
                }
                BER_BVZERO( &op2->ors_attrs[i].an_name );
-       } else {
-               ptr = (char *)(op2->o_hdr + 1);
        }
+
        op2->o_authz = op->o_authz;
        op2->o_ndn.bv_val = ptr;
        ptr = lutil_strcopy(ptr, op->o_ndn.bv_val) + 1;
@@ -1919,16 +1967,27 @@ syncprov_search_response( Operation *op, SlapReply *rs )
                        int i, sid;
                        sid = slap_parse_csn_sid( &a->a_nvals[0] );
 
-                       /* Make sure entry is less than the snapshot'd contextCSN */
-                       for ( i=0; i<ss->ss_numcsns; i++ ) {
-                               if ( sid == ss->ss_sids[i] && ber_bvcmp( &a->a_nvals[0],
-                                       &ss->ss_ctxcsn[i] ) > 0 ) {
-                                       Debug( LDAP_DEBUG_SYNC,
-                                               "Entry %s CSN %s greater than snapshot %s\n",
-                                               rs->sr_entry->e_name.bv_val,
-                                               a->a_nvals[0].bv_val,
-                                               ss->ss_ctxcsn[i].bv_val );
-                                       return LDAP_SUCCESS;
+                       /* Don't send changed entries back to the originator */
+                       if ( sid == srs->sr_state.sid && srs->sr_state.numcsns ) {
+                               Debug( LDAP_DEBUG_SYNC,
+                                       "Entry %s changed by peer, ignored\n",
+                                       rs->sr_entry->e_name.bv_val, 0, 0 );
+                               return LDAP_SUCCESS;
+                       }
+
+                       /* If not a persistent search */
+                       if ( !ss->ss_so ) {
+                               /* Make sure entry is less than the snapshot'd contextCSN */
+                               for ( i=0; i<ss->ss_numcsns; i++ ) {
+                                       if ( sid == ss->ss_sids[i] && ber_bvcmp( &a->a_nvals[0],
+                                               &ss->ss_ctxcsn[i] ) > 0 ) {
+                                               Debug( LDAP_DEBUG_SYNC,
+                                                       "Entry %s CSN %s greater than snapshot %s\n",
+                                                       rs->sr_entry->e_name.bv_val,
+                                                       a->a_nvals[0].bv_val,
+                                                       ss->ss_ctxcsn[i].bv_val );
+                                               return LDAP_SUCCESS;
+                                       }
                                }
                        }
 
@@ -1956,24 +2015,32 @@ syncprov_search_response( Operation *op, SlapReply *rs )
        } else if ( rs->sr_type == REP_RESULT && rs->sr_err == LDAP_SUCCESS ) {
                struct berval cookie;
 
-               slap_compose_sync_cookie( op, &cookie, ss->ss_ctxcsn,
-                       srs->sr_state.rid );
+               if ( ss->ss_flags & SS_CHANGED ) {
+                       slap_compose_sync_cookie( op, &cookie, ss->ss_ctxcsn,
+                               srs->sr_state.rid, srs->sr_state.sid );
+
+                       Debug( LDAP_DEBUG_SYNC, "syncprov_search_response: cookie=%s\n", cookie.bv_val, 0, 0 );
+               }
 
-               /* Is this a regular refresh? */
+               /* Is this a regular refresh?
+                * Note: refresh never gets here if there were no changes
+                */
                if ( !ss->ss_so ) {
                        rs->sr_ctrls = op->o_tmpalloc( sizeof(LDAPControl *)*2,
                                op->o_tmpmemctx );
                        rs->sr_ctrls[1] = NULL;
                        rs->sr_err = syncprov_done_ctrl( op, rs, rs->sr_ctrls,
-                               0, 1, &cookie, ss->ss_present ?  LDAP_SYNC_REFRESH_PRESENTS :
+                               0, 1, &cookie, ( ss->ss_flags & SS_PRESENT ) ?  LDAP_SYNC_REFRESH_PRESENTS :
                                        LDAP_SYNC_REFRESH_DELETES );
                        op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
                } else {
                /* It's RefreshAndPersist, transition to Persist phase */
-                       syncprov_sendinfo( op, rs, ss->ss_present ?
+                       syncprov_sendinfo( op, rs, ( ss->ss_flags & SS_PRESENT ) ?
                                LDAP_TAG_SYNC_REFRESH_PRESENT : LDAP_TAG_SYNC_REFRESH_DELETE,
-                               &cookie, 1, NULL, 0 );
-                       op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
+                               ( ss->ss_flags & SS_CHANGED ) ? &cookie : NULL,
+                               1, NULL, 0 );
+                       if ( ss->ss_flags & SS_CHANGED )
+                               op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );
 
                        /* Detach this Op from frontend control */
                        ldap_pvt_thread_mutex_lock( &ss->ss_so->s_mutex );
@@ -2001,7 +2068,7 @@ syncprov_op_search( Operation *op, SlapReply *rs )
        slap_overinst           *on = (slap_overinst *)op->o_bd->bd_info;
        syncprov_info_t         *si = (syncprov_info_t *)on->on_bi.bi_private;
        slap_callback   *cb;
-       int gotstate = 0, nochange = 0, do_present;
+       int gotstate = 0, changed = 0, do_present = 0;
        syncops *sop = NULL;
        searchstate *ss;
        sync_control *srs;
@@ -2016,8 +2083,6 @@ syncprov_op_search( Operation *op, SlapReply *rs )
                return rs->sr_err;
        }
 
-       do_present = si->si_nopres ? 0 : 1;
-
        srs = op->o_controls[slap_cids.sc_LDAPsync];
        op->o_managedsait = SLAP_CONTROL_NONCRITICAL;
 
@@ -2051,6 +2116,7 @@ syncprov_op_search( Operation *op, SlapReply *rs )
                *sop = so;
                ldap_pvt_thread_mutex_init( &sop->s_mutex );
                sop->s_rid = srs->sr_state.rid;
+               sop->s_sid = srs->sr_state.sid;
                sop->s_inuse = 1;
 
                ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
@@ -2060,19 +2126,33 @@ syncprov_op_search( Operation *op, SlapReply *rs )
        }
 
        /* snapshot the ctxcsn */
-       ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
-       ber_bvarray_dup_x( &ctxcsn, si->si_ctxcsn, op->o_tmpmemctx );
+       ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
        numcsns = si->si_numcsns;
-       sids = op->o_tmpalloc( numcsns * sizeof(int), op->o_tmpmemctx );
-       for ( i=0; i<numcsns; i++ )
-               sids[i] = si->si_sids[i];
-       ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+       if ( numcsns ) {
+               ber_bvarray_dup_x( &ctxcsn, si->si_ctxcsn, op->o_tmpmemctx );
+               sids = op->o_tmpalloc( numcsns * sizeof(int), op->o_tmpmemctx );
+               for ( i=0; i<numcsns; i++ )
+                       sids[i] = si->si_sids[i];
+       } else {
+               ctxcsn = NULL;
+               sids = NULL;
+       }
+       ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
        
        /* If we have a cookie, handle the PRESENT lookups */
        if ( srs->sr_state.ctxcsn ) {
                sessionlog *sl;
                int i, j;
 
+               /* If we don't have any CSN of our own yet, pretend nothing
+                * has changed.
+                */
+               if ( !numcsns )
+                       goto no_change;
+
+               if ( !si->si_nopres )
+                       do_present = SS_PRESENT;
+
                /* If there are SIDs we don't recognize in the cookie, drop them */
                for (i=0; i<srs->sr_state.numcsns; ) {
                        for (j=0; j<numcsns; j++) {
@@ -2103,21 +2183,21 @@ syncprov_op_search( Operation *op, SlapReply *rs )
 
                /* If nothing has changed, shortcut it */
                if ( srs->sr_state.numcsns == numcsns ) {
-                       int i, j, changed = 0;
+                       int i, j;
                        for ( i=0; i<srs->sr_state.numcsns; i++ ) {
                                for ( j=0; j<numcsns; j++ ) {
                                        if ( srs->sr_state.sids[i] != sids[j] )
                                                continue;
                                        if ( !bvmatch( &srs->sr_state.ctxcsn[i], &ctxcsn[j] ))
-                                               changed = 1;
+                                               changed = SS_CHANGED;
                                        break;
                                }
                                if ( changed )
                                        break;
                        }
                        if ( !changed ) {
-                               nochange = 1;
-                               if ( !(op->o_sync_mode & SLAP_SYNC_PERSIST) ) {
+                               do_present = 0;
+no_change:             if ( !(op->o_sync_mode & SLAP_SYNC_PERSIST) ) {
                                        LDAPControl     *ctrls[2];
 
                                        ctrls[0] = NULL;
@@ -2153,6 +2233,10 @@ syncprov_op_search( Operation *op, SlapReply *rs )
                        /* No, so a reload is required */
                        /* the 2.2 consumer doesn't send this hint */
                        if ( si->si_usehint && srs->sr_rhint == 0 ) {
+                               if ( ctxcsn )
+                                       ber_bvarray_free_x( ctxcsn, op->o_tmpmemctx );
+                               if ( sids )
+                                       op->o_tmpfree( sids, op->o_tmpmemctx );
                                send_ldap_error( op, rs, LDAP_SYNC_REFRESH_REQUIRED, "sync cookie is stale" );
                                return rs->sr_err;
                        }
@@ -2161,10 +2245,17 @@ syncprov_op_search( Operation *op, SlapReply *rs )
                        /* If changed and doing Present lookup, send Present UUIDs */
                        if ( do_present && syncprov_findcsn( op, FIND_PRESENT ) !=
                                LDAP_SUCCESS ) {
+                               if ( ctxcsn )
+                                       ber_bvarray_free_x( ctxcsn, op->o_tmpmemctx );
+                               if ( sids )
+                                       op->o_tmpfree( sids, op->o_tmpmemctx );
                                send_ldap_result( op, rs );
                                return rs->sr_err;
                        }
                }
+       } else {
+               /* No consumer state, assume something has changed */
+               changed = SS_CHANGED;
        }
 
 shortcut:
@@ -2176,7 +2267,7 @@ shortcut:
        }
 
        /* If something changed, find the changes */
-       if ( gotstate && !nochange ) {
+       if ( gotstate && changed ) {
                Filter *fand, *fava;
 
                fand = op->o_tmpalloc( sizeof(Filter), op->o_tmpmemctx );
@@ -2203,7 +2294,7 @@ shortcut:
        ss = (searchstate *)(cb+1);
        ss->ss_on = on;
        ss->ss_so = sop;
-       ss->ss_present = do_present;
+       ss->ss_flags = do_present | changed;
        ss->ss_ctxcsn = ctxcsn;
        ss->ss_numcsns = numcsns;
        ss->ss_sids = sids;
@@ -2217,7 +2308,7 @@ shortcut:
         * the refresh phase, just invoke the response callback to transition
         * us into persist phase
         */
-       if ( nochange ) {
+       if ( !changed ) {
                rs->sr_err = LDAP_SUCCESS;
                rs->sr_nentries = 0;
                send_ldap_result( op, rs );
@@ -2234,6 +2325,12 @@ syncprov_operational(
        slap_overinst           *on = (slap_overinst *)op->o_bd->bd_info;
        syncprov_info_t         *si = (syncprov_info_t *)on->on_bi.bi_private;
 
+       /* This prevents generating unnecessarily; frontend will strip
+        * any statically stored copy.
+        */
+       if ( op->o_sync != SLAP_CONTROL_NONE )
+               return SLAP_CB_CONTINUE;
+
        if ( rs->sr_entry &&
                dn_match( &rs->sr_entry->e_nname, op->o_bd->be_nsuffix )) {
 
@@ -2246,7 +2343,7 @@ syncprov_operational(
                                        break;
                        }
 
-                       ldap_pvt_thread_mutex_lock( &si->si_csn_mutex );
+                       ldap_pvt_thread_rdwr_rlock( &si->si_csn_rwlock );
                        if ( si->si_ctxcsn ) {
                                if ( !a ) {
                                        for ( ap = &rs->sr_operational_attrs; *ap;
@@ -2264,12 +2361,17 @@ syncprov_operational(
                                                a = attr_find( rs->sr_entry->e_attrs,
                                                        slap_schema.si_ad_contextCSN );
                                        }
-                                       free( a->a_vals );
+                                       if ( a->a_nvals != a->a_vals ) {
+                                               ber_bvarray_free( a->a_nvals );
+                                       }
+                                       a->a_nvals = NULL;
+                                       ber_bvarray_free( a->a_vals );
+                                       a->a_vals = NULL;
+                                       a->a_numvals = 0;
                                }
-                               ber_bvarray_dup_x( &a->a_vals, si->si_ctxcsn, NULL );
-                               a->a_nvals = a->a_vals;
+                               attr_valadd( a, si->si_ctxcsn, si->si_ctxcsn, si->si_numcsns );
                        }
-                       ldap_pvt_thread_mutex_unlock( &si->si_csn_mutex );
+                       ldap_pvt_thread_rdwr_runlock( &si->si_csn_rwlock );
                }
        }
        return SLAP_CB_CONTINUE;
@@ -2326,10 +2428,14 @@ sp_cf_gen(ConfigArgs *c)
                case SP_CHKPT:
                        if ( si->si_chkops || si->si_chktime ) {
                                struct berval bv;
-                               bv.bv_len = sprintf( c->msg, "%d %d",
-                                       si->si_chkops, si->si_chktime );
-                               bv.bv_val = c->msg;
-                               value_add_one( &c->rvalue_vals, &bv );
+                               bv.bv_len = snprintf( c->cr_msg, sizeof( c->cr_msg ),
+                                       "%d %d", si->si_chkops, si->si_chktime );
+                               if ( bv.bv_len < 0 || bv.bv_len >= sizeof( c->cr_msg ) ) {
+                                       rc = 1;
+                               } else {
+                                       bv.bv_val = c->cr_msg;
+                                       value_add_one( &c->rvalue_vals, &bv );
+                               }
                        } else {
                                rc = 1;
                        }
@@ -2387,31 +2493,31 @@ sp_cf_gen(ConfigArgs *c)
        switch ( c->type ) {
        case SP_CHKPT:
                if ( lutil_atoi( &si->si_chkops, c->argv[1] ) != 0 ) {
-                       snprintf( c->msg, sizeof( c->msg ), "%s unable to parse checkpoint ops # \"%s\"",
+                       snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s unable to parse checkpoint ops # \"%s\"",
                                c->argv[0], c->argv[1] );
                        Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-                               "%s: %s\n", c->log, c->msg, 0 );
+                               "%s: %s\n", c->log, c->cr_msg, 0 );
                        return ARG_BAD_CONF;
                }
                if ( si->si_chkops <= 0 ) {
-                       snprintf( c->msg, sizeof( c->msg ), "%s invalid checkpoint ops # \"%d\"",
+                       snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s invalid checkpoint ops # \"%d\"",
                                c->argv[0], si->si_chkops );
                        Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-                               "%s: %s\n", c->log, c->msg, 0 );
+                               "%s: %s\n", c->log, c->cr_msg, 0 );
                        return ARG_BAD_CONF;
                }
                if ( lutil_atoi( &si->si_chktime, c->argv[2] ) != 0 ) {
-                       snprintf( c->msg, sizeof( c->msg ), "%s unable to parse checkpoint time \"%s\"",
+                       snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s unable to parse checkpoint time \"%s\"",
                                c->argv[0], c->argv[1] );
                        Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-                               "%s: %s\n", c->log, c->msg, 0 );
+                               "%s: %s\n", c->log, c->cr_msg, 0 );
                        return ARG_BAD_CONF;
                }
                if ( si->si_chktime <= 0 ) {
-                       snprintf( c->msg, sizeof( c->msg ), "%s invalid checkpoint time \"%d\"",
+                       snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s invalid checkpoint time \"%d\"",
                                c->argv[0], si->si_chkops );
                        Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-                               "%s: %s\n", c->log, c->msg, 0 );
+                               "%s: %s\n", c->log, c->cr_msg, 0 );
                        return ARG_BAD_CONF;
                }
                si->si_chktime *= 60;
@@ -2421,10 +2527,10 @@ sp_cf_gen(ConfigArgs *c)
                int size = c->value_int;
 
                if ( size < 0 ) {
-                       snprintf( c->msg, sizeof( c->msg ), "%s size %d is negative",
+                       snprintf( c->cr_msg, sizeof( c->cr_msg ), "%s size %d is negative",
                                c->argv[0], size );
                        Debug( LDAP_DEBUG_CONFIG|LDAP_DEBUG_NONE,
-                               "%s: %s\n", c->log, c->msg, 0 );
+                               "%s: %s\n", c->log, c->cr_msg, 0 );
                        return ARG_BAD_CONF;
                }
                sl = si->si_logs;
@@ -2468,16 +2574,17 @@ syncprov_db_otask(
  */
 static int
 syncprov_db_open(
-    BackendDB *be
+       BackendDB *be,
+       ConfigReply *cr
 )
 {
        slap_overinst   *on = (slap_overinst *) be->bd_info;
        syncprov_info_t *si = (syncprov_info_t *)on->on_bi.bi_private;
 
        Connection conn = { 0 };
-       OperationBuffer opbuf = { 0 };
-       Operation *op = (Operation *) &opbuf;
-       Entry *e;
+       OperationBuffer opbuf;
+       Operation *op;
+       Entry *e = NULL;
        Attribute *a;
        int rc;
        void *thrctx = NULL;
@@ -2498,29 +2605,26 @@ syncprov_db_open(
        }
 
        thrctx = ldap_pvt_thread_pool_context();
-       connection_fake_init( &conn, op, thrctx );
+       connection_fake_init( &conn, &opbuf, thrctx );
+       op = &opbuf.ob_op;
        op->o_bd = be;
        op->o_dn = be->be_rootdn;
        op->o_ndn = be->be_rootndn;
 
-       op->o_bd->bd_info = on->on_info->oi_orig;
-       rc = be_entry_get_rw( op, be->be_nsuffix, NULL,
-               slap_schema.si_ad_contextCSN, 0, &e );
+       rc = overlay_entry_get_ov( op, be->be_nsuffix, NULL,
+               slap_schema.si_ad_contextCSN, 0, &e, on );
 
        if ( e ) {
                ldap_pvt_thread_t tid;
 
                a = attr_find( e->e_attrs, slap_schema.si_ad_contextCSN );
                if ( a ) {
-                       int i;
                        ber_bvarray_dup_x( &si->si_ctxcsn, a->a_vals, NULL );
-                       for ( i=0; !BER_BVISEMPTY( &a->a_vals[i] ); i++ );
-                       si->si_numcsns = i;
-                       si->si_sids = slap_parse_csn_sids( si->si_ctxcsn, i );
+                       si->si_numcsns = a->a_numvals;
+                       si->si_sids = slap_parse_csn_sids( si->si_ctxcsn, a->a_numvals, NULL );
                }
-               be_entry_release_rw( op, e, 0 );
+               overlay_entry_release_ov( op, e, 0, on );
                if ( si->si_ctxcsn ) {
-                       op->o_bd->bd_info = (BackendInfo *)on;
                        op->o_req_dn = be->be_suffix[0];
                        op->o_req_ndn = be->be_nsuffix[0];
                        op->ors_scope = LDAP_SCOPE_SUBTREE;
@@ -2534,10 +2638,10 @@ syncprov_db_open(
                char csnbuf[ LDAP_LUTIL_CSNSTR_BUFSIZE ];
                struct berval csn;
 
-               if ( SLAP_SYNC_SHADOW( op->o_bd ) && SLAP_SINGLE_SHADOW( op->o_bd )) {
-               /* If we're also a consumer, and we're not multimaster,
-                * then don't generate anything, wait for our provider to send it
-                * to us.
+               if ( SLAP_SYNC_SHADOW( op->o_bd )) {
+               /* If we're also a consumer, then don't generate anything.
+                * Wait for our provider to send it to us, or for a local
+                * modify if we have multimaster.
                 */
                        goto out;
                }
@@ -2562,7 +2666,8 @@ out:
  */
 static int
 syncprov_db_close(
-    BackendDB *be
+       BackendDB *be,
+       ConfigReply *cr
 )
 {
     slap_overinst   *on = (slap_overinst *) be->bd_info;
@@ -2572,14 +2677,15 @@ syncprov_db_close(
                return 0;
        }
        if ( si->si_numops ) {
-               Connection conn;
+               Connection conn = {0};
                OperationBuffer opbuf;
-               Operation *op = (Operation *) &opbuf;
+               Operation *op;
                SlapReply rs = {REP_RESULT};
                void *thrctx;
 
                thrctx = ldap_pvt_thread_pool_context();
-               connection_fake_init( &conn, op, thrctx );
+               connection_fake_init( &conn, &opbuf, thrctx );
+               op = &opbuf.ob_op;
                op->o_bd = be;
                op->o_dn = be->be_rootdn;
                op->o_ndn = be->be_rootndn;
@@ -2591,7 +2697,8 @@ syncprov_db_close(
 
 static int
 syncprov_db_init(
-       BackendDB *be
+       BackendDB *be,
+       ConfigReply *cr
 )
 {
        slap_overinst   *on = (slap_overinst *)be->bd_info;
@@ -2606,7 +2713,7 @@ syncprov_db_init(
 
        si = ch_calloc(1, sizeof(syncprov_info_t));
        on->on_bi.bi_private = si;
-       ldap_pvt_thread_mutex_init( &si->si_csn_mutex );
+       ldap_pvt_thread_rdwr_init( &si->si_csn_rwlock );
        ldap_pvt_thread_mutex_init( &si->si_ops_mutex );
        ldap_pvt_thread_mutex_init( &si->si_mods_mutex );
 
@@ -2623,7 +2730,8 @@ syncprov_db_init(
 
 static int
 syncprov_db_destroy(
-       BackendDB *be
+       BackendDB *be,
+       ConfigReply *cr
 )
 {
        slap_overinst   *on = (slap_overinst *)be->bd_info;
@@ -2641,9 +2749,13 @@ syncprov_db_destroy(
                                
                        ch_free( si->si_logs );
                }
+               if ( si->si_ctxcsn )
+                       ber_bvarray_free( si->si_ctxcsn );
+               if ( si->si_sids )
+                       ch_free( si->si_sids );
                ldap_pvt_thread_mutex_destroy( &si->si_mods_mutex );
                ldap_pvt_thread_mutex_destroy( &si->si_ops_mutex );
-               ldap_pvt_thread_mutex_destroy( &si->si_csn_mutex );
+               ldap_pvt_thread_rdwr_destroy( &si->si_csn_rwlock );
                ch_free( si );
        }
 
@@ -2674,8 +2786,13 @@ static int syncprov_parseCtrl (
                return LDAP_PROTOCOL_ERROR;
        }
 
+       if ( BER_BVISNULL( &ctrl->ldctl_value ) ) {
+               rs->sr_text = "Sync control value is absent";
+               return LDAP_PROTOCOL_ERROR;
+       }
+
        if ( BER_BVISEMPTY( &ctrl->ldctl_value ) ) {
-               rs->sr_text = "Sync control value is empty (or absent)";
+               rs->sr_text = "Sync control value is empty";
                return LDAP_PROTOCOL_ERROR;
        }
 
@@ -2733,10 +2850,14 @@ static int syncprov_parseCtrl (
        sr->sr_rhint = rhint;
        if (!BER_BVISNULL(&cookie)) {
                ber_dupbv_x( &sr->sr_state.octet_str, &cookie, op->o_tmpmemctx );
-               slap_parse_sync_cookie( &sr->sr_state, op->o_tmpmemctx );
-               if ( sr->sr_state.rid == -1 ) {
-                       rs->sr_text = "Sync control : cookie parsing error";
-                       return LDAP_PROTOCOL_ERROR;
+               /* If parse fails, pretend no cookie was sent */
+               if ( slap_parse_sync_cookie( &sr->sr_state, op->o_tmpmemctx ) ||
+                       sr->sr_state.rid == -1 ) {
+                       if ( sr->sr_state.ctxcsn ) {
+                               ber_bvarray_free_x( sr->sr_state.ctxcsn, op->o_tmpmemctx );
+                               sr->sr_state.ctxcsn = NULL;
+                       }
+                       sr->sr_state.numcsns = 0;
                }
        }