]> git.sur5r.net Git - openldap/commitdiff
Server Side Sorting (also with PagedResults). VLV still in progress.
authorHoward Chu <hyc@openldap.org>
Mon, 13 Jul 2009 08:39:22 +0000 (08:39 +0000)
committerHoward Chu <hyc@openldap.org>
Mon, 13 Jul 2009 08:39:22 +0000 (08:39 +0000)
servers/slapd/overlays/sssvlv.c [new file with mode: 0644]

diff --git a/servers/slapd/overlays/sssvlv.c b/servers/slapd/overlays/sssvlv.c
new file mode 100644 (file)
index 0000000..0131c21
--- /dev/null
@@ -0,0 +1,1013 @@
+/* sssvlv.c - server side sort / virtual list view */
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 2009 The OpenLDAP Foundation.
+ * Portions copyright 2009 Symas Corporation.
+ * 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 Howard Chu for inclusion in
+ * OpenLDAP Software.
+ */
+
+#include "portable.h"
+
+#define SLAPD_OVER_SSSVLV      SLAPD_MOD_DYNAMIC
+
+#ifdef SLAPD_OVER_SSSVLV
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/ctype.h>
+
+#include <avl.h>
+
+#include "slap.h"
+#include "lutil.h"
+
+/* RFC2891: Server Side Sorting
+ * RFC2696: Paged Results
+ */
+#ifndef LDAP_MATCHRULE_IDENTIFIER
+#define LDAP_MATCHRULE_IDENTIFIER      0x80L
+#define LDAP_REVERSEORDER_IDENTIFIER   0x81L
+#define LDAP_ATTRTYPES_IDENTIFIER      0x80L
+#endif
+
+/* draft-ietf-ldapext-ldapv3-vlv-09.txt: Virtual List Views
+ */
+#ifndef LDAP_VLVBYINDEX_IDENTIFIER
+#define LDAP_VLVBYINDEX_IDENTIFIER        0xa0L
+#define LDAP_VLVBYVALUE_IDENTIFIER     0x81L
+#define LDAP_VLVCONTEXT_IDENTIFIER     0x04L
+
+#define LDAP_VLV_SSS_MISSING   0x4C
+#define LDAP_VLV_RANGE_ERROR   0x4D
+#endif
+
+#define SAFESTR(macro_str, macro_def) ((macro_str) ? (macro_str) : (macro_def))
+
+typedef struct vlv_ctrl {
+       int vc_before;
+       int vc_after;
+       int     vc_offset;
+       int vc_count;
+       struct berval vc_value;
+       unsigned long vc_context;
+} vlv_ctrl;
+
+typedef struct sort_key
+{
+       AttributeDescription    *sk_ad;
+       MatchingRule                    *sk_ordering;
+       int                                             sk_direction;   /* 1=normal, -1=reverse */
+} sort_key;
+
+typedef struct sort_ctrl {
+       int sc_nkeys;
+       sort_key sc_keys[0];
+} sort_ctrl;
+
+
+typedef struct sort_node
+{
+       int sn_conn;
+       struct berval sn_dn;
+       struct berval *sn_vals;
+} sort_node;
+
+typedef struct sssvlv_info
+{
+       int svi_max;    /* max concurrent sorts */
+       int svi_num;    /* current # sorts */
+       int svi_max_keys;       /* max sort keys per request */
+} sssvlv_info;
+
+typedef struct sort_op
+{
+       Avlnode *so_tree;
+       sort_ctrl *so_ctrl;
+       sssvlv_info *so_info;
+       int so_paged;
+       int so_page_size;
+       int so_nentries;
+       int so_vlv;
+       int so_vlv_rc;
+       int so_vlv_target;
+       unsigned long so_vcontext;
+} sort_op;
+
+/* There is only one conn table for all overlay instances */
+static sort_op **sort_conns;
+static ldap_pvt_thread_mutex_t sort_conns_mutex;
+static const char *debug_header = "sssvlv";
+
+static int sss_cid;
+static int vlv_cid;
+
+/* RFC 2981 Section 2.2
+ * If a sort key is a multi-valued attribute, and an entry happens to
+ * have multiple values for that attribute and no other controls are
+ * present that affect the sorting order, then the server SHOULD use the
+ * least value (according to the ORDERING rule for that attribute).
+ */
+static struct berval* select_value(
+       Attribute               *attr,
+       sort_key                        *key )
+{
+       struct berval* ber1, *ber2;
+       MatchingRule *mr = key->sk_ordering;
+       int i, cmp;
+
+       ber1 = &(attr->a_nvals[0]);
+       ber2 = ber1+1;
+       for ( i = 1; i < attr->a_numvals; i++,ber2++ ) {
+               mr->smr_match( &cmp, 0, mr->smr_syntax, mr, ber1, ber2 );
+               if ( cmp > 0 ) {
+                       ber1 = ber2;
+               }
+       }
+
+       Debug(LDAP_DEBUG_TRACE, "%s: value selected for compare: %s\n",
+               debug_header,
+               SAFESTR(ber1->bv_val, "<Empty>"),
+               0);
+
+       return ber1;
+}
+
+static int node_cmp( const void* val1, const void* val2 )
+{
+       sort_node *sn1 = (sort_node *)val1;
+       sort_node *sn2 = (sort_node *)val2;
+       sort_ctrl *sc = sort_conns[sn1->sn_conn]->so_ctrl;
+       MatchingRule *mr;
+       int i, cmp = 0;
+
+       for ( i=0; cmp == 0 && i<sc->sc_nkeys; i++ ) {
+               if ( BER_BVISNULL( &sn1->sn_vals[i] )) {
+                       if ( BER_BVISNULL( &sn2->sn_vals[i] ))
+                               cmp = 0;
+                       else
+                               cmp = sc->sc_keys[i].sk_direction;
+               } else if ( BER_BVISNULL( &sn2->sn_vals[i] )) {
+                       cmp = sc->sc_keys[i].sk_direction * -1;
+               } else {
+                       mr = sc->sc_keys[i].sk_ordering;
+                       mr->smr_match( &cmp, 0, mr->smr_syntax, mr,
+                               &sn1->sn_vals[i], &sn2->sn_vals[i] );
+               }
+       }
+       /* Never return equal so that new entries are always inserted */
+       return cmp < 0 ? -1 : 1;
+}
+
+static int pack_vlv_response_control(
+       Operation               *op,
+       SlapReply               *rs,
+       sort_op                 *so,
+       LDAPControl     **ctrlsp )
+{
+       LDAPControl                     *ctrl;
+       BerElementBuffer        berbuf;
+       BerElement                      *ber            = (BerElement *)&berbuf;
+       PagedResultsCookie      resp_cookie;
+       struct berval           cookie, bv;
+       int                                     rc;
+
+       ber_init2( ber, NULL, LBER_USE_DER );
+       ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+       rc = ber_printf( ber, "{iii", so->so_vlv_target, so->so_nentries,
+               so->so_vlv_rc );
+
+       if ( rc != -1 && so->so_vcontext ) {
+               cookie.bv_val = (char *)&so->so_vcontext;
+               cookie.bv_len = sizeof(so->so_vcontext);
+               rc = ber_printf( ber, "tO", LDAP_VLVCONTEXT_IDENTIFIER, &cookie );
+       }
+
+       if ( rc != -1 ) {
+               rc = ber_printf( ber, "}" );
+       }
+
+       if ( rc != -1 ) {
+               rc = ber_flatten2( ber, &bv, 0 );
+       }
+
+       if ( rc != -1 ) {
+               ctrl = (LDAPControl *)op->o_tmpalloc( sizeof(LDAPControl)+
+                       bv.bv_len, op->o_tmpmemctx );
+               ctrl->ldctl_oid                 = LDAP_CONTROL_VLVRESPONSE;
+               ctrl->ldctl_iscritical  = 0;
+               ctrl->ldctl_value.bv_val = (char *)(ctrl+1);
+               ctrl->ldctl_value.bv_len = bv.bv_len;
+               AC_MEMCPY( ctrl->ldctl_value.bv_val, bv.bv_val, bv.bv_len );
+               ctrlsp[0] = ctrl;
+       } else {
+               ctrlsp[0] = NULL;
+               rs->sr_err = LDAP_OTHER;
+       }
+
+       ber_free_buf( ber );
+
+       return rs->sr_err;
+}
+
+static int pack_pagedresult_response_control(
+       Operation               *op,
+       SlapReply               *rs,
+       sort_op                 *so,
+       LDAPControl     **ctrlsp )
+{
+       LDAPControl                     *ctrl;
+       BerElementBuffer        berbuf;
+       BerElement                      *ber            = (BerElement *)&berbuf;
+       PagedResultsCookie      resp_cookie;
+       struct berval           cookie, bv;
+       int                                     rc;
+
+       ber_init2( ber, NULL, LBER_USE_DER );
+       ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+       if ( so->so_nentries > 0 ) {
+               resp_cookie             = ( PagedResultsCookie )so->so_tree;
+               cookie.bv_len   = sizeof( PagedResultsCookie );
+               cookie.bv_val   = (char *)&resp_cookie;
+       } else {
+               resp_cookie             = ( PagedResultsCookie )0;
+               BER_BVZERO( &cookie );
+       }
+
+       op->o_conn->c_pagedresults_state.ps_cookie = resp_cookie;
+       op->o_conn->c_pagedresults_state.ps_count
+               = ((PagedResultsState *)op->o_pagedresults_state)->ps_count
+                 + rs->sr_nentries;
+
+       rc = ber_printf( ber, "{iO}", so->so_nentries, &cookie );
+       if ( rc != -1 ) {
+               rc = ber_flatten2( ber, &bv, 0 );
+       }
+
+       if ( rc != -1 ) {
+               ctrl = (LDAPControl *)op->o_tmpalloc( sizeof(LDAPControl)+
+                       bv.bv_len, op->o_tmpmemctx );
+               ctrl->ldctl_oid                 = LDAP_CONTROL_PAGEDRESULTS;
+               ctrl->ldctl_iscritical  = 0;
+               ctrl->ldctl_value.bv_val = (char *)(ctrl+1);
+               ctrl->ldctl_value.bv_len = bv.bv_len;
+               AC_MEMCPY( ctrl->ldctl_value.bv_val, bv.bv_val, bv.bv_len );
+               ctrlsp[0] = ctrl;
+       } else {
+               ctrlsp[0] = NULL;
+               rs->sr_err = LDAP_OTHER;
+       }
+
+       ber_free_buf( ber );
+
+       return rs->sr_err;
+}
+
+static int pack_sss_response_control(
+       Operation               *op,
+       SlapReply               *rs,
+       LDAPControl     **ctrlsp )
+{
+       LDAPControl                     *ctrl;
+       BerElementBuffer        berbuf;
+       BerElement                      *ber            = (BerElement *)&berbuf;
+       struct berval           bv;
+       int                                     rc;
+
+       ber_init2( ber, NULL, LBER_USE_DER );
+       ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );
+
+       /* Pack error code */
+       rc = ber_printf(ber, "{e}", rs->sr_err);
+
+       if ( rc != -1)
+               rc = ber_flatten2( ber, &bv, 0 );
+
+       if ( rc != -1 ) {
+               ctrl = (LDAPControl *)op->o_tmpalloc( sizeof(LDAPControl)+
+                       bv.bv_len, op->o_tmpmemctx );
+               ctrl->ldctl_oid                 = LDAP_CONTROL_SORTRESPONSE;
+               ctrl->ldctl_iscritical  = 0;
+               ctrl->ldctl_value.bv_val = (char *)(ctrl+1);
+               ctrl->ldctl_value.bv_len = bv.bv_len;
+               AC_MEMCPY( ctrl->ldctl_value.bv_val, bv.bv_val, bv.bv_len );
+               ctrlsp[0] = ctrl;
+       } else {
+               ctrlsp[0] = NULL;
+               rs->sr_err = LDAP_OTHER;
+       }
+
+       ber_free_buf( ber );
+
+       return rs->sr_err;
+}
+
+static void free_sort_op( Connection *conn, sort_op *so )
+{
+       if ( so->so_tree ) {
+               tavl_free( so->so_tree, ch_free );
+               so->so_tree = NULL;
+       }
+
+       ldap_pvt_thread_mutex_lock( &sort_conns_mutex );
+       sort_conns[conn->c_conn_idx] = NULL;
+       so->so_info->svi_num--;
+       ldap_pvt_thread_mutex_unlock( &sort_conns_mutex );
+
+       ch_free( so );
+}
+
+static void send_page( Operation *op, SlapReply *rs, sort_op *so )
+{
+       Avlnode         *cur_node               = so->so_tree;
+       Avlnode         *next_node              = NULL;
+       BackendDB *be = op->o_bd;
+       sort_node *sn;
+       Entry *e;
+       int rc;
+
+       while ( cur_node && rs->sr_nentries < so->so_page_size ) {
+               sort_node *sn = cur_node->avl_data;
+
+               next_node = tavl_next( cur_node, TAVL_DIR_RIGHT );
+
+
+               op->o_bd = select_backend( &sn->sn_dn, 0 );
+               e = NULL;
+               rc = be_entry_get_rw( op, &sn->sn_dn, NULL, NULL, 0, &e );
+
+               ch_free( cur_node->avl_data );
+               ber_memfree( cur_node );
+
+               cur_node = next_node;
+               so->so_nentries--;
+
+               if ( e && rc == LDAP_SUCCESS ) {
+                       rs->sr_entry = e;
+                       rs->sr_flags = REP_ENTRY_MUSTRELEASE;
+                       rs->sr_err = send_search_entry( op, rs );
+                       if ( rs->sr_err == LDAP_UNAVAILABLE )
+                               break;
+               }
+       }
+
+       /* Set the first entry to send for the next page */
+       so->so_tree = next_node;
+
+       op->o_bd = be;
+}
+
+static int send_entry(
+       Operation               *op,
+       SlapReply               *rs,
+       sort_op                 *so)
+{
+       Debug(LDAP_DEBUG_TRACE,
+               "%s: response control: status=%d, text=%s\n",
+               debug_header, rs->sr_err, SAFESTR(rs->sr_text, "<None>"));
+
+       /* RFC 2891: If critical then send the entries iff they were
+        * succesfully sorted.  If non-critical send all entries
+        * whether they were sorted or not.
+        */
+       if ( (op->o_ctrlflag[sss_cid] != SLAP_CONTROL_CRITICAL) ||
+                (rs->sr_err == LDAP_SUCCESS) )
+       {
+               /* Get the first node to send */
+               Avlnode *start_node = tavl_end(so->so_tree, TAVL_DIR_LEFT);
+               so->so_tree = start_node;
+
+               if ( so->so_paged <= SLAP_CONTROL_IGNORED ) {
+                       /* Not paged result search.  Send all entries.
+                        * Set the page size to the number of entries
+                        * so that send_page() will send all entries.
+                        */
+                       so->so_page_size = so->so_nentries;
+               }
+
+               send_page( op, rs, so );
+       }
+
+       return SLAP_CB_CONTINUE;
+}
+
+static void send_result(
+       Operation               *op,
+       SlapReply               *rs,
+       sort_op                 *so)
+{
+       LDAPControl *ctrls[3];
+       int rc;
+
+       rc = pack_sss_response_control( op, rs, ctrls );
+       if ( rc == LDAP_SUCCESS && so->so_paged > SLAP_CONTROL_IGNORED ) {
+               rc = pack_pagedresult_response_control( op, rs, so, ctrls+1 );
+               ctrls[2] = NULL;
+       } else {
+               ctrls[1] = NULL;
+       }
+
+       if ( ctrls[0] != NULL )
+               slap_add_ctrls( op, rs, ctrls );
+       send_ldap_result( op, rs );
+
+       if ( so->so_tree == NULL ) {
+               /* Search finished, so clean up */
+               free_sort_op( op->o_conn, so );
+       }
+}
+
+static int sssvlv_op_response(
+       Operation       *op,
+       SlapReply       *rs )
+{
+       sort_ctrl *sc = op->o_controls[sss_cid];
+       sort_op *so = op->o_callback->sc_private;
+       int rc = SLAP_CB_CONTINUE;
+
+       if ( rs->sr_type == REP_SEARCH ) {
+               int i;
+               size_t len;
+               sort_node *sn, *sn2;
+               struct berval *bv;
+               char *ptr;
+
+               len = sizeof(sort_node) + sc->sc_nkeys * sizeof(struct berval) +
+                       rs->sr_entry->e_nname.bv_len + 1;
+               sn = op->o_tmpalloc( len, op->o_tmpmemctx );
+               sn->sn_vals = (struct berval *)(sn+1);
+
+               /* Build tmp list of key values */
+               for ( i=0; i<sc->sc_nkeys; i++ ) {
+                       Attribute *a = attr_find( rs->sr_entry->e_attrs,
+                               sc->sc_keys[i].sk_ad );
+                       if ( a ) {
+                               if ( a->a_numvals > 1 ) {
+                                       bv = select_value( a, &sc->sc_keys[i] );
+                               } else {
+                                       bv = a->a_nvals;
+                               }
+                               sn->sn_vals[i] = *bv;
+                               len += bv->bv_len + 1;
+                       } else {
+                               BER_BVZERO( &sn->sn_vals[i] );
+                       }
+               }
+
+               /* Now dup into regular memory */
+               sn2 = ch_malloc( len );
+               sn2->sn_vals = (struct berval *)(sn2+1);
+               AC_MEMCPY( sn2->sn_vals, sn->sn_vals,
+                               sc->sc_nkeys * sizeof(struct berval));
+               sn = sn2;
+
+               ptr = (char *)(sn->sn_vals + sc->sc_nkeys);
+               sn->sn_dn.bv_val = ptr;
+               sn->sn_dn.bv_len = rs->sr_entry->e_nname.bv_len;
+               AC_MEMCPY( ptr, rs->sr_entry->e_nname.bv_val,
+                       rs->sr_entry->e_nname.bv_len );
+               ptr += rs->sr_entry->e_nname.bv_len;
+               *ptr++ = '\0';
+               for ( i=0; i<sc->sc_nkeys; i++ ) {
+                       if ( !BER_BVISNULL( &sn->sn_vals[i] )) {
+                               AC_MEMCPY( ptr, sn->sn_vals[i].bv_val, sn->sn_vals[i].bv_len );
+                               sn->sn_vals[i].bv_val = ptr;
+                               ptr += sn->sn_vals[i].bv_len;
+                               *ptr++ = '\0';
+                       }
+               }
+               sn->sn_conn = op->o_conn->c_conn_idx;
+
+               /* Insert into the AVL tree */
+               tavl_insert(&(so->so_tree), sn, node_cmp, avl_dup_ok);
+
+               so->so_nentries++;
+
+               /* Collected the keys so that they can be sorted.  Thus, stop
+                * the entry from propagating.
+                */
+               rc = LDAP_SUCCESS;
+       }
+       else if ( rs->sr_type == REP_RESULT ) {
+               /* Remove serversort response callback.
+                * We don't want the entries that we are about to send to be
+                * processed by serversort response again.
+                */
+               if ( op->o_callback->sc_response == sssvlv_op_response ) {
+                       op->o_callback = op->o_callback->sc_next;
+               }
+
+               rc = send_entry( op, rs, so );
+               send_result( op, rs, so );
+       }
+
+       return rc;
+}
+
+static int sssvlv_op_search(
+       Operation               *op,
+       SlapReply               *rs)
+{
+       slap_overinst                   *on                     = (slap_overinst *)op->o_bd->bd_info;
+       sssvlv_info                             *si                     = on->on_bi.bi_private;
+       int                                             rc                      = SLAP_CB_CONTINUE;
+       int     ok;
+       sort_op *so, so2;
+       sort_ctrl *sc = op->o_controls[sss_cid];
+       PagedResultsState *ps;
+       vlv_ctrl *vc;
+
+       if ( op->o_ctrlflag[sss_cid] <= SLAP_CONTROL_IGNORED ) {
+               if ( op->o_ctrlflag[vlv_cid] > SLAP_CONTROL_IGNORED ) {
+                       LDAPControl *ctrls[2];
+                       so2.so_vcontext = 0;
+                       so2.so_vlv_target = 0;
+                       so2.so_nentries = 0;
+                       so2.so_vlv_rc = LDAP_VLV_SSS_MISSING;
+                       rc = pack_vlv_response_control( op, rs, &so2, ctrls );
+                       if ( rc == LDAP_SUCCESS ) {
+                               ctrls[1] = NULL;
+                               slap_add_ctrls( op, rs, ctrls );
+                       }
+                       rs->sr_err = LDAP_VLV_ERROR;
+                       rs->sr_text = "Sort control is required with VLV";
+                       goto leave;
+               }
+               /* Not server side sort so just continue */
+               return SLAP_CB_CONTINUE;
+       }
+
+       Debug(LDAP_DEBUG_TRACE,
+               "==> sssvlv_search: <%s> %s, control flag: %d\n",
+               op->o_req_dn.bv_val, op->ors_filterstr.bv_val,
+               op->o_ctrlflag[sss_cid]);
+
+       if ( sc->sc_nkeys > si->svi_max_keys ) {
+               rs->sr_text = "Too many sort keys";
+               rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+               goto leave;
+       }
+
+       ps = ( op->o_pagedresults > SLAP_CONTROL_IGNORED ) ?
+               (PagedResultsState*)(op->o_pagedresults_state) : NULL;
+       vc = op->o_ctrlflag[vlv_cid] > SLAP_CONTROL_IGNORED ?
+               op->o_controls[vlv_cid] : NULL;
+
+       if ( ps && vc ) {
+               rs->sr_text = "VLV incompatible with PagedResults";
+               rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
+               goto leave;
+       }
+
+       ok = 1;
+       ldap_pvt_thread_mutex_lock( &sort_conns_mutex );
+       so = sort_conns[op->o_conn->c_conn_idx];
+       /* Is there already a sort running on this conn? */
+       if ( so ) {
+               /* Is it a continuation of a VLV search? */
+               if ( !vc || so->so_vlv <= SLAP_CONTROL_IGNORED ||
+                       vc->vc_context != so->so_vcontext ) {
+                       /* Is it a continuation of a paged search? */
+                       if ( !ps || so->so_paged <= SLAP_CONTROL_IGNORED ||
+                               op->o_conn->c_pagedresults_state.ps_cookie != ps->ps_cookie ) {
+                               ok = 0;
+                       } else if ( !ps->ps_size ) {
+                       /* Abandoning current request */
+                               ok = 0;
+                       }
+               }
+       /* Are there too many running overall? */
+       } else if ( si->svi_num >= si->svi_max ) {
+               ok = 0;
+       } else {
+               /* OK, this connection now has a sort running */
+               si->svi_num++;
+               sort_conns[op->o_conn->c_conn_idx] = &so2;
+       }
+       ldap_pvt_thread_mutex_unlock( &sort_conns_mutex );
+       if ( ok ) {
+               /* are we continuing a paged search? */
+               if ( ps && ps->ps_cookie ) {
+                       so->so_ctrl = sc;
+                       send_page( op, rs, so );
+                       send_result( op, rs, so );
+                       rc = LDAP_SUCCESS;
+               }
+               else {
+                       slap_callback *cb = op->o_tmpalloc( sizeof(slap_callback),
+                               op->o_tmpmemctx );
+                       /* Install serversort response callback to handle a new search */
+                       if ( ps ) {
+                               so = ch_malloc( sizeof(sort_op));
+                       } else {
+                               so = op->o_tmpalloc( sizeof(sort_op), op->o_tmpmemctx );
+                       }
+                       sort_conns[op->o_conn->c_conn_idx] = so;
+
+                       cb->sc_cleanup          = NULL;
+                       cb->sc_response         = sssvlv_op_response;
+                       cb->sc_next                     = op->o_callback;
+                       cb->sc_private          = so;
+
+                       so->so_tree = NULL;
+                       so->so_ctrl = sc;
+                       so->so_info = si;
+                       if ( ps ) {
+                               so->so_paged = op->o_pagedresults;
+                               so->so_page_size = ps->ps_size;
+                               op->o_pagedresults = SLAP_CONTROL_IGNORED;
+                       } else {
+                               so->so_paged = 0;
+                               so->so_page_size = 0;
+                       }
+                       so->so_nentries = 0;
+
+                       op->o_callback          = cb;
+               }
+       } else {
+               if ( ps && !ps->ps_size ) {
+                       free_sort_op( op->o_conn, so );
+                       rs->sr_err = LDAP_SUCCESS;
+               } else {
+                       rs->sr_text = "Other sort requests already in progress";
+                       rs->sr_err = LDAP_BUSY;
+               }
+leave:
+               rc = rs->sr_err;
+               send_ldap_result( op, rs );
+       }
+
+       return rc;
+}
+
+static int get_ordering_rule(
+       AttributeDescription    *ad,
+       struct berval                   *matchrule,
+       SlapReply                               *rs,
+       MatchingRule                    **ordering )
+{
+       MatchingRule* mr;
+
+       if ( matchrule && matchrule->bv_val ) {
+               mr = mr_find( matchrule->bv_val );
+               if ( mr == NULL ) {
+                       rs->sr_err = LDAP_INAPPROPRIATE_MATCHING;
+                       rs->sr_text = "serverSort control: No ordering rule";
+                       Debug(LDAP_DEBUG_TRACE, "%s: no ordering rule function for %s\n",
+                               debug_header, matchrule->bv_val, 0);
+               }
+       }
+       else {
+               mr = ad->ad_type->sat_ordering;
+               if ( mr == NULL ) {
+                       rs->sr_err = LDAP_INAPPROPRIATE_MATCHING;
+                       rs->sr_text = "serverSort control: No ordering rule";
+                       Debug(LDAP_DEBUG_TRACE,
+                               "%s: no ordering rule specified and no default ordering rule for attribute %s\n",
+                               debug_header, ad->ad_cname.bv_val, 0);
+               }
+       }
+
+       *ordering = mr;
+       return rs->sr_err;
+}
+
+static int count_key(BerElement *ber)
+{
+       char *end;
+       ber_len_t len;
+       ber_tag_t tag;
+       int count = 0;
+
+       /* Server Side Sort Control is a SEQUENCE of SEQUENCE */
+       for ( tag = ber_first_element( ber, &len, &end );
+                 tag == LBER_SEQUENCE;
+                 tag = ber_next_element( ber, &len, end ))
+       {
+               tag = ber_skip_tag( ber, &len );
+               ber_skip_data( ber, len );
+               ++count;
+       }
+       ber_rewind( ber );
+
+       return count;
+}
+
+static int build_key(
+       BerElement              *ber,
+       SlapReply               *rs,
+       sort_key                        *key )
+{
+       struct berval attr;
+       struct berval matchrule = BER_BVNULL;
+       ber_int_t reverse = 0;
+       ber_tag_t tag;
+       ber_len_t len;
+       MatchingRule *ordering = NULL;
+       AttributeDescription *ad = NULL;
+       const char *text;
+
+       if (( tag = ber_scanf( ber, "{" )) == LBER_ERROR ) {
+               rs->sr_text = "serverSort control: decoding error";
+               rs->sr_err = LDAP_PROTOCOL_ERROR;
+               return rs->sr_err;
+       }
+
+       if (( tag = ber_scanf( ber, "m", &attr )) == LBER_ERROR ) {
+               rs->sr_text = "serverSort control: attribute decoding error";
+               rs->sr_err = LDAP_PROTOCOL_ERROR;
+               return rs->sr_err;
+       }
+
+       tag = ber_peek_tag( ber, &len );
+       if ( tag == LDAP_MATCHRULE_IDENTIFIER ) {
+               if (( tag = ber_scanf( ber, "m", &matchrule )) == LBER_ERROR ) {
+                       rs->sr_text = "serverSort control: matchrule decoding error";
+                       rs->sr_err = LDAP_PROTOCOL_ERROR;
+                       return rs->sr_err;
+               }
+               tag = ber_peek_tag( ber, &len );
+       }
+
+       if ( tag == LDAP_REVERSEORDER_IDENTIFIER ) {
+               if (( tag = ber_scanf( ber, "b", &reverse )) == LBER_ERROR ) {
+                       rs->sr_text = "serverSort control: reverse decoding error";
+                       rs->sr_err = LDAP_PROTOCOL_ERROR;
+                       return rs->sr_err;
+               }
+       }
+
+       if (( tag = ber_scanf( ber, "}" )) == LBER_ERROR ) {
+               rs->sr_text = "serverSort control: decoding error";
+               rs->sr_err = LDAP_PROTOCOL_ERROR;
+               return rs->sr_err;
+       }
+
+       if ( slap_bv2ad( &attr, &ad, &text ) != LDAP_SUCCESS ) {
+               rs->sr_text =
+                       "serverSort control: Unrecognized attribute type in sort key";
+               Debug(LDAP_DEBUG_TRACE,
+                       "%s: Unrecognized attribute type in sort key: %s\n",
+                       debug_header, SAFESTR(attr.bv_val, "<None>"), 0);
+               rs->sr_err = LDAP_NO_SUCH_ATTRIBUTE;
+               return rs->sr_err;
+       }
+
+       /* get_ordering_rule will set sr_err and sr_text */
+       get_ordering_rule( ad, &matchrule, rs, &ordering );
+       if ( rs->sr_err != LDAP_SUCCESS ) {
+               return rs->sr_err;
+       }
+
+       key->sk_ad = ad;
+       key->sk_ordering = ordering;
+       key->sk_direction = reverse ? -1 : 1;
+
+       return rs->sr_err;
+}
+
+static int sss_parseCtrl(
+       Operation               *op,
+       SlapReply               *rs,
+       LDAPControl             *ctrl )
+{
+       BerElementBuffer        berbuf;
+       BerElement                      *ber;
+       ber_tag_t               tag;
+       ber_len_t               len;
+       int                                     i;
+       sort_ctrl       *sc;
+
+       rs->sr_err = LDAP_PROTOCOL_ERROR;
+
+       if ( op->o_ctrlflag[sss_cid] > SLAP_CONTROL_IGNORED ) {
+               rs->sr_text = "sorted results control specified multiple times";
+       } else if ( BER_BVISNULL( &ctrl->ldctl_value ) ) {
+               rs->sr_text = "sorted results control value is absent";
+       } else if ( BER_BVISEMPTY( &ctrl->ldctl_value ) ) {
+               rs->sr_text = "sorted results control value is empty";
+       } else {
+               rs->sr_err = LDAP_SUCCESS;
+       }
+       if ( rs->sr_err != LDAP_SUCCESS )
+               return rs->sr_err;
+
+       op->o_ctrlflag[sss_cid] = ctrl->ldctl_iscritical ?
+               SLAP_CONTROL_CRITICAL : SLAP_CONTROL_NONCRITICAL;
+
+       ber = (BerElement *)&berbuf;
+       ber_init2( ber, &ctrl->ldctl_value, 0 );
+       i = count_key( ber );
+
+       sc = op->o_tmpalloc( sizeof(sort_ctrl) +
+               i * sizeof(sort_key), op->o_tmpmemctx );
+       sc->sc_nkeys = i;
+       op->o_controls[sss_cid] = sc;
+
+       /* peel off initial sequence */
+       ber_scanf( ber, "{" );
+
+       i = 0;
+       do {
+               if ( build_key( ber, rs, &sc->sc_keys[i] ) != LDAP_SUCCESS )
+                       break;
+               i++;
+               tag = ber_peek_tag( ber, &len );
+       } while ( tag != LBER_DEFAULT );
+
+       return rs->sr_err;
+}
+
+static int vlv_parseCtrl(
+       Operation               *op,
+       SlapReply               *rs,
+       LDAPControl             *ctrl )
+{
+       BerElementBuffer        berbuf;
+       BerElement                      *ber;
+       ber_tag_t               tag;
+       ber_len_t               len;
+       int                                     i;
+       vlv_ctrl        *vc, vc2;
+
+       rs->sr_err = LDAP_PROTOCOL_ERROR;
+       rs->sr_text = NULL;
+
+       if ( op->o_ctrlflag[vlv_cid] > SLAP_CONTROL_IGNORED ) {
+               rs->sr_text = "vlv control specified multiple times";
+       } else if ( BER_BVISNULL( &ctrl->ldctl_value ) ) {
+               rs->sr_text = "vlv control value is absent";
+       } else if ( BER_BVISEMPTY( &ctrl->ldctl_value ) ) {
+               rs->sr_text = "vlv control value is empty";
+       }
+       if ( rs->sr_text != NULL )
+               return rs->sr_err;
+
+       op->o_ctrlflag[vlv_cid] = ctrl->ldctl_iscritical ?
+               SLAP_CONTROL_CRITICAL : SLAP_CONTROL_NONCRITICAL;
+
+       ber = (BerElement *)&berbuf;
+       ber_init2( ber, &ctrl->ldctl_value, 0 );
+
+       rs->sr_err = LDAP_PROTOCOL_ERROR;
+
+       tag = ber_scanf( ber, "{ii", &vc2.vc_before, &vc2.vc_after );
+       if ( tag == LBER_ERROR ) {
+               return rs->sr_err;
+       }
+
+       tag = ber_peek_tag( ber, &len );
+       if ( tag == LDAP_VLVBYINDEX_IDENTIFIER ) {
+               tag = ber_scanf( ber, "ii", &vc2.vc_offset, &vc2.vc_count );
+               if ( tag == LBER_ERROR )
+                       return rs->sr_err;
+               BER_BVZERO( &vc2.vc_value );
+       } else if ( tag == LDAP_VLVBYVALUE_IDENTIFIER ) {
+               tag = ber_scanf( ber, "m", &vc2.vc_value );
+               if ( tag == LBER_ERROR || BER_BVISNULL( &vc2.vc_value ))
+                       return rs->sr_err;
+       } else {
+               return rs->sr_err;
+       }
+       tag = ber_peek_tag( ber, &len );
+       if ( tag == LDAP_VLVCONTEXT_IDENTIFIER ) {
+               struct berval bv;
+               tag = ber_scanf( ber, "m", &bv );
+               if ( tag == LBER_ERROR || bv.bv_len != sizeof(vc2.vc_context))
+                       return rs->sr_err;
+               AC_MEMCPY( &vc2.vc_context, bv.bv_val, bv.bv_len );
+       } else {
+               vc2.vc_context = 0;
+       }
+
+       vc = op->o_tmpalloc( sizeof(vlv_ctrl), op->o_tmpmemctx );
+       *vc = vc2;
+       op->o_controls[vlv_cid] = vc;
+       rs->sr_err = LDAP_SUCCESS;
+
+       return rs->sr_err;
+}
+
+static int sssvlv_connection_destroy( BackendDB *be, Connection *conn )
+{
+       slap_overinst   *on             = (slap_overinst *)be->bd_info;
+
+       if ( sort_conns[conn->c_conn_idx] )
+               free_sort_op( conn, sort_conns[conn->c_conn_idx] );
+
+       return LDAP_SUCCESS;
+}
+
+static int sssvlv_db_open(
+       BackendDB               *be,
+       ConfigReply             *cr )
+{
+       int rc = overlay_register_control( be, LDAP_CONTROL_SORTREQUEST );
+       if ( rc == LDAP_SUCCESS )
+               rc = overlay_register_control( be, LDAP_CONTROL_VLVREQUEST );
+       return rc;
+}
+
+static int sssvlv_db_init(
+       BackendDB               *be,
+       ConfigReply             *cr)
+{
+       slap_overinst   *on = (slap_overinst *)be->bd_info;
+       sssvlv_info *si;
+       
+       si = (sssvlv_info *)ch_malloc(sizeof(sssvlv_info));
+       on->on_bi.bi_private = si;
+
+       si->svi_max = 5;
+       si->svi_num = 0;
+       si->svi_max_keys = 5;
+
+       if ( dtblsize && !sort_conns ) {
+               ldap_pvt_thread_mutex_init( &sort_conns_mutex );
+               /* accommodate for c_conn_idx == -1 */
+               sort_conns = ch_calloc( sizeof(sort_op *), dtblsize + 1 );
+               sort_conns++;
+       }
+
+       return LDAP_SUCCESS;
+}
+
+static int sssvlv_db_destroy(
+       BackendDB               *be,
+       ConfigReply             *cr )
+{
+       slap_overinst   *on = (slap_overinst *)be->bd_info;
+       sssvlv_info *si = (sssvlv_info *)on->on_bi.bi_private;
+       
+       if ( si ) {
+               ch_free( si );
+               on->on_bi.bi_private = NULL;
+       }
+       return LDAP_SUCCESS;
+}
+
+static slap_overinst sssvlv;
+
+int sssvlv_initialize()
+{
+       int rc;
+
+       sssvlv.on_bi.bi_type                            = "sssvlv";
+       sssvlv.on_bi.bi_db_init                         = sssvlv_db_init;
+       sssvlv.on_bi.bi_db_destroy                      = sssvlv_db_destroy;
+       sssvlv.on_bi.bi_db_open                         = sssvlv_db_open;
+       sssvlv.on_bi.bi_connection_destroy      = sssvlv_connection_destroy;
+       sssvlv.on_bi.bi_op_search                       = sssvlv_op_search;
+
+       rc = register_supported_control2( LDAP_CONTROL_SORTREQUEST,
+                       SLAP_CTRL_SEARCH,
+                       NULL,
+                       sss_parseCtrl,
+                       1 /* replace */,
+                       &sss_cid );
+
+       if ( rc == LDAP_SUCCESS ) {
+               rc = register_supported_control2( LDAP_CONTROL_VLVREQUEST,
+                       SLAP_CTRL_SEARCH,
+                       NULL,
+                       vlv_parseCtrl,
+                       1 /* replace */,
+                       &vlv_cid );
+       }
+
+       if ( rc == LDAP_SUCCESS ) {
+               rc = overlay_register( &sssvlv );
+               if ( rc != LDAP_SUCCESS ) {
+                       fprintf( stderr, "Failed to register server side sort overlay\n" );
+               }
+       }
+       else {
+               fprintf( stderr, "Failed to register control %d\n", rc );
+       }
+
+       return rc;
+}
+
+#if SLAPD_OVER_SSSVLV == SLAPD_MOD_DYNAMIC
+int init_module( int argc, char *argv[])
+{
+       return sssvlv_initialize();
+}
+#endif
+
+#endif /* SLAPD_OVER_SSSVLV */