text: /* id2entry.c - routines to deal with the id2entry database */
  /* $OpenLDAP$ */
  /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   *
   * Copyright 2000-2018 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>.
   */
  
  #include "portable.h"
  
  #include <stdio.h>
  #include <ac/string.h>
  #include <ac/errno.h>
  
  #include "back-bdb.h"
  
  static int bdb_id2entry_put(
  	BackendDB *be,
  	DB_TXN *tid,
  	Entry *e,
  	int flag )
  {
  	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
  	DB *db = bdb->bi_id2entry->bdi_db;
  	DBT key, data;
  	struct berval bv;
  	int rc;
  	ID nid;
  #ifdef BDB_HIER
  	struct berval odn, ondn;
  
  	/* We only store rdns, and they go in the dn2id database. */
  
  	odn = e->e_name; ondn = e->e_nname;
  
  	e->e_name = slap_empty_bv;
  	e->e_nname = slap_empty_bv;
  #endif
  	DBTzero( &key );
  
  	/* Store ID in BigEndian format */
  	key.data = &nid;
  	key.size = sizeof(ID);
  	BDB_ID2DISK( e->e_id, &nid );
  
  	rc = entry_encode( e, &bv );
  #ifdef BDB_HIER
  	e->e_name = odn; e->e_nname = ondn;
  #endif
  	if( rc != LDAP_SUCCESS ) {
  		return -1;
  	}
  
  	DBTzero( &data );
  	bv2DBT( &bv, &data );
  
  	rc = db->put( db, tid, &key, &data, flag );
  
  	free( bv.bv_val );
  	return rc;
  }
  
  /*
   * This routine adds (or updates) an entry on disk.
   * The cache should be already be updated.
   */
  
  
  int bdb_id2entry_add(
  	BackendDB *be,
  	DB_TXN *tid,
  	Entry *e )
  {
  	return bdb_id2entry_put(be, tid, e, DB_NOOVERWRITE);
  }
  
  int bdb_id2entry_update(
  	BackendDB *be,
  	DB_TXN *tid,
  	Entry *e )
  {
  	return bdb_id2entry_put(be, tid, e, 0);
  }
  
  int bdb_id2entry(
  	BackendDB *be,
  	DB_TXN *tid,
  	ID id,
  	Entry **e )
  {
  	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
  	DB *db = bdb->bi_id2entry->bdi_db;
  	DBT key, data;
  	DBC *cursor;
  	EntryHeader eh;
  	char buf[16];
  	int rc = 0, off;
  	ID nid;
  
  	*e = NULL;
  
  	DBTzero( &key );
  	key.data = &nid;
  	key.size = sizeof(ID);
  	BDB_ID2DISK( id, &nid );
  
  	DBTzero( &data );
  	data.flags = DB_DBT_USERMEM | DB_DBT_PARTIAL;
  
  	/* fetch it */
  	rc = db->cursor( db, tid, &cursor, bdb->bi_db_opflags );
  	if ( rc ) return rc;
  
  	/* Get the nattrs / nvals counts first */
  	data.ulen = data.dlen = sizeof(buf);
  	data.data = buf;
  	rc = cursor->c_get( cursor, &key, &data, DB_SET );
  	if ( rc ) goto finish;
  
  
  	eh.bv.bv_val = buf;
  	eh.bv.bv_len = data.size;
  	rc = entry_header( &eh );
  	if ( rc ) goto finish;
  
  	if ( eh.nvals ) {
  		/* Get the size */
  		data.flags ^= DB_DBT_PARTIAL;
  		data.ulen = 0;
  		rc = cursor->c_get( cursor, &key, &data, DB_CURRENT );
  		if ( rc != DB_BUFFER_SMALL ) goto finish;
  
  		/* Allocate a block and retrieve the data */
  		off = eh.data - eh.bv.bv_val;
  		eh.bv.bv_len = eh.nvals * sizeof( struct berval ) + data.size;
  		eh.bv.bv_val = ch_malloc( eh.bv.bv_len );
  		eh.data = eh.bv.bv_val + eh.nvals * sizeof( struct berval );
  		data.data = eh.data;
  		data.ulen = data.size;
  
  		/* skip past already parsed nattr/nvals */
  		eh.data += off;
  
  		rc = cursor->c_get( cursor, &key, &data, DB_CURRENT );
  	}
  
  finish:
  	cursor->c_close( cursor );
  
  	if( rc != 0 ) {
  		return rc;
  	}
  
  	if ( eh.nvals ) {
  #ifdef SLAP_ZONE_ALLOC
  		rc = entry_decode(&eh, e, bdb->bi_cache.c_zctx);
  #else
  		rc = entry_decode(&eh, e);
  #endif
  	} else {
  		*e = entry_alloc();
  	}
  
  	if( rc == 0 ) {
  		(*e)->e_id = id;
  	} else {
  		/* only free on error. On success, the entry was
  		 * decoded in place.
  		 */
  #ifndef SLAP_ZONE_ALLOC
  		ch_free(eh.bv.bv_val);
  #endif
  	}
  #ifdef SLAP_ZONE_ALLOC
  	ch_free(eh.bv.bv_val);
  #endif
  
  	return rc;
  }
  
  int bdb_id2entry_delete(
  	BackendDB *be,
  	DB_TXN *tid,
  	Entry *e )
  {
  	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
  	DB *db = bdb->bi_id2entry->bdi_db;
  	DBT key;
  	int rc;
  	ID nid;
  
  	DBTzero( &key );
  	key.data = &nid;
  	key.size = sizeof(ID);
  	BDB_ID2DISK( e->e_id, &nid );
  
  	/* delete from database */
  	rc = db->del( db, tid, &key, 0 );
  
  	return rc;
  }
  
  int bdb_entry_return(
  	Entry *e
  )
  {
  	/* Our entries are allocated in two blocks; the data comes from
  	 * the db itself and the Entry structure and associated pointers
  	 * are allocated in entry_decode. The db data pointer is saved
  	 * in e_bv.
  	 */
  	if ( e->e_bv.bv_val ) {
  		/* See if the DNs were changed by modrdn */
  		if( e->e_nname.bv_val < e->e_bv.bv_val || e->e_nname.bv_val >
  			e->e_bv.bv_val + e->e_bv.bv_len ) {
  			ch_free(e->e_name.bv_val);
  			ch_free(e->e_nname.bv_val);
  		}
  		e->e_name.bv_val = NULL;
  		e->e_nname.bv_val = NULL;
  		/* In tool mode the e_bv buffer is realloc'd, leave it alone */
  		if( !(slapMode & SLAP_TOOL_MODE) ) {
  			free( e->e_bv.bv_val );
  		}
  		BER_BVZERO( &e->e_bv );
  	}
  	entry_free( e );
  	return 0;
  }
  
  int bdb_entry_release(
  	Operation *op,
  	Entry *e,
  	int rw )
  {
  	struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
  	struct bdb_op_info *boi;
  	OpExtra *oex;
   
  	/* slapMode : SLAP_SERVER_MODE, SLAP_TOOL_MODE,
  			SLAP_TRUNCATE_MODE, SLAP_UNDEFINED_MODE */
   
  	if ( slapMode & SLAP_SERVER_MODE ) {
  		/* If not in our cache, just free it */
  		if ( !e->e_private ) {
  #ifdef SLAP_ZONE_ALLOC
  			return bdb_entry_return( bdb, e, -1 );
  #else
  			return bdb_entry_return( e );
  #endif
  		}
  		/* free entry and reader or writer lock */
  		LDAP_SLIST_FOREACH( oex, &op->o_extra, oe_next ) {
  			if ( oex->oe_key == bdb ) break;
  		}
  		boi = (struct bdb_op_info *)oex;
  
  		/* lock is freed with txn */
  		if ( !boi || boi->boi_txn ) {
  			bdb_unlocked_cache_return_entry_rw( bdb, e, rw );
  		} else {
  			struct bdb_lock_info *bli, *prev;
  			for ( prev=(struct bdb_lock_info *)&boi->boi_locks,
  				bli = boi->boi_locks; bli; prev=bli, bli=bli->bli_next ) {
  				if ( bli->bli_id == e->e_id ) {
  					bdb_cache_return_entry_rw( bdb, e, rw, &bli->bli_lock );
  					prev->bli_next = bli->bli_next;
  					/* Cleanup, or let caller know we unlocked */
  					if ( bli->bli_flag & BLI_DONTFREE )
  						bli->bli_flag = 0;
  					else
  						op->o_tmpfree( bli, op->o_tmpmemctx );
  					break;
  				}
  			}
  			if ( !boi->boi_locks ) {
  				LDAP_SLIST_REMOVE( &op->o_extra, &boi->boi_oe, OpExtra, oe_next );
  				if ( !(boi->boi_flag & BOI_DONTFREE))
  					op->o_tmpfree( boi, op->o_tmpmemctx );
  			}
  		}
  	} else {
  #ifdef SLAP_ZONE_ALLOC
  		int zseq = -1;
  		if (e->e_private != NULL) {
  			BEI(e)->bei_e = NULL;
  			zseq = BEI(e)->bei_zseq;
  		}
  #else
  		if (e->e_private != NULL)
  			BEI(e)->bei_e = NULL;
  #endif
  		e->e_private = NULL;
  #ifdef SLAP_ZONE_ALLOC
  		bdb_entry_return ( bdb, e, zseq );
  #else
  		bdb_entry_return ( e );
  #endif
  	}
   
  	return 0;
  }
  
  /* return LDAP_SUCCESS IFF we can retrieve the specified entry.
   */
  int bdb_entry_get(
  	Operation *op,
  	struct berval *ndn,
  	ObjectClass *oc,
  	AttributeDescription *at,
  	int rw,
  	Entry **ent )
  {
  	struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
  	struct bdb_op_info *boi = NULL;
  	DB_TXN *txn = NULL;
  	Entry *e = NULL;
  	EntryInfo *ei;
  	int	rc;
  	const char *at_name = at ? at->ad_cname.bv_val : "(null)";
  
  	DB_LOCK		lock;
  
  	Debug( LDAP_DEBUG_ARGS,
  		"=> bdb_entry_get: ndn: \"%s\"\n", ndn->bv_val, 0, 0 ); 
  	Debug( LDAP_DEBUG_ARGS,
  		"=> bdb_entry_get: oc: \"%s\", at: \"%s\"\n",
  		oc ? oc->soc_cname.bv_val : "(null)", at_name, 0);
  
  	if( op ) {
  		OpExtra *oex;
  		LDAP_SLIST_FOREACH( oex, &op->o_extra, oe_next ) {
  			if ( oex->oe_key == bdb ) break;
  		}
  		boi = (struct bdb_op_info *)oex;
  		if ( boi )
  			txn = boi->boi_txn;
  	}
  
  	if ( !txn ) {
  		rc = bdb_reader_get( op, bdb->bi_dbenv, &txn );
  		switch(rc) {
  		case 0:
  			break;
  		default:
  			return LDAP_OTHER;
  		}
  	}
  
  dn2entry_retry:
  	/* can we find entry */
  	rc = bdb_dn2entry( op, txn, ndn, &ei, 0, &lock );
  	switch( rc ) {
  	case DB_NOTFOUND:
  	case 0:
  		break;
  	case DB_LOCK_DEADLOCK:
  	case DB_LOCK_NOTGRANTED:
  		/* the txn must abort and retry */
  		if ( txn ) {
  			if ( boi ) boi->boi_err = rc;
  			return LDAP_BUSY;
  		}
  		ldap_pvt_thread_yield();
  		goto dn2entry_retry;
  	default:
  		if ( boi ) boi->boi_err = rc;
  		return (rc != LDAP_BUSY) ? LDAP_OTHER : LDAP_BUSY;
  	}
  	if (ei) e = ei->bei_e;
  	if (e == NULL) {
  		Debug( LDAP_DEBUG_ACL,
  			"=> bdb_entry_get: cannot find entry: \"%s\"\n",
  				ndn->bv_val, 0, 0 ); 
  		return LDAP_NO_SUCH_OBJECT; 
  	}
  	
  	Debug( LDAP_DEBUG_ACL,
  		"=> bdb_entry_get: found entry: \"%s\"\n",
  		ndn->bv_val, 0, 0 ); 
  
  	if ( oc && !is_entry_objectclass( e, oc, 0 )) {
  		Debug( LDAP_DEBUG_ACL,
  			"<= bdb_entry_get: failed to find objectClass %s\n",
  			oc->soc_cname.bv_val, 0, 0 ); 
  		rc = LDAP_NO_SUCH_ATTRIBUTE;
  		goto return_results;
  	}
  
  	/* NOTE: attr_find() or attrs_find()? */
  	if ( at && attr_find( e->e_attrs, at ) == NULL ) {
  		Debug( LDAP_DEBUG_ACL,
  			"<= bdb_entry_get: failed to find attribute %s\n",
  			at->ad_cname.bv_val, 0, 0 ); 
  		rc = LDAP_NO_SUCH_ATTRIBUTE;
  		goto return_results;
  	}
  
  return_results:
  	if( rc != LDAP_SUCCESS ) {
  		/* free entry */
  		bdb_cache_return_entry_rw(bdb, e, rw, &lock);
  
  	} else {
  		if ( slapMode & SLAP_SERVER_MODE ) {
  			*ent = e;
  			/* big drag. we need a place to store a read lock so we can
  			 * release it later?? If we're in a txn, nothing is needed
  			 * here because the locks will go away with the txn.
  			 */
  			if ( op ) {
  				if ( !boi ) {
  					boi = op->o_tmpcalloc(1,sizeof(struct bdb_op_info),op->o_tmpmemctx);
  					boi->boi_oe.oe_key = bdb;
  					LDAP_SLIST_INSERT_HEAD( &op->o_extra, &boi->boi_oe, oe_next );
  				}
  				if ( !boi->boi_txn ) {
  					struct bdb_lock_info *bli;
  					bli = op->o_tmpalloc( sizeof(struct bdb_lock_info),
  						op->o_tmpmemctx );
  					bli->bli_next = boi->boi_locks;
  					bli->bli_id = e->e_id;
  					bli->bli_flag = 0;
  					bli->bli_lock = lock;
  					boi->boi_locks = bli;
  				}
  			}
  		} else {
  			*ent = entry_dup( e );
  			bdb_cache_return_entry_rw(bdb, e, rw, &lock);
  		}
  	}
  
  	Debug( LDAP_DEBUG_TRACE,
  		"bdb_entry_get: rc=%d\n",
  		rc, 0, 0 ); 
  	return(rc);
  }
  