389-ds-base/ldap/servers/slapd/back-ldbm/ldbm_modify.c

/** BEGIN COPYRIGHT BLOCK
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; version 2 of the License.
 * 
 * This Program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this Program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA.
 * 
 * In addition, as a special exception, Red Hat, Inc. gives You the additional
 * right to link the code of this Program with code not covered under the GNU
 * General Public License ("Non-GPL Code") and to distribute linked combinations
 * including the two, subject to the limitations in this paragraph. Non-GPL Code
 * permitted under this exception must only link to the code of this Program
 * through those well defined interfaces identified in the file named EXCEPTION
 * found in the source code files (the "Approved Interfaces"). The files of
 * Non-GPL Code may instantiate templates or use macros or inline functions from
 * the Approved Interfaces without causing the resulting work to be covered by
 * the GNU General Public License. Only Red Hat, Inc. may make changes or
 * additions to the list of Approved Interfaces. You must obey the GNU General
 * Public License in all respects for all of the Program code and other code used
 * in conjunction with the Program except the Non-GPL Code covered by this
 * exception. If you modify this file, you may extend this exception to your
 * version of the file, but you are not obligated to do so. If you do not wish to
 * provide this exception without modification, you must delete this exception
 * statement from your version and license this file solely under the GPL without
 * exception. 
 * 
 * 
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
 * All rights reserved.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

/* modify.c - ldbm backend modify routine */

#include "back-ldbm.h"

extern char *numsubordinates;
extern char *hassubordinates;

static void remove_illegal_mods(LDAPMod **mods);
static int mods_have_effect (Slapi_Entry *entry, Slapi_Mods *smods);

#define MOD_SET_ERROR(rc, error, count)                                        \
{                                                                              \
    (rc) = (error);                                                            \
    (count) = RETRY_TIMES; /* otherwise, the transaction may not be aborted */ \
}

/* Modify context structure constructor, sans allocation */
void modify_init(modify_context *mc,struct backentry *old_entry)
{
	/* Store the old entry */
	PR_ASSERT(NULL == mc->old_entry);
	PR_ASSERT(NULL == mc->new_entry);

	mc->old_entry = old_entry;
	mc->attr_encrypt = 1;
}

int modify_apply_mods(modify_context *mc, Slapi_Mods *smods)
{
	return modify_apply_mods_ignore_error(mc, smods, -1);
}

int modify_apply_mods_ignore_error(modify_context *mc, Slapi_Mods *smods, int error)
{
	int ret = 0;
	/* Make a copy of the entry */
	PR_ASSERT(mc->old_entry != NULL);
	PR_ASSERT(mc->new_entry == NULL);
	mc->new_entry = backentry_dup(mc->old_entry);
	PR_ASSERT(smods!=NULL);
	if ( mods_have_effect (mc->new_entry->ep_entry, smods) ) {
		ret = entry_apply_mods_ignore_error( mc->new_entry->ep_entry, slapi_mods_get_ldapmods_byref(smods), error);
	}
	mc->smods= smods;
	if (error == ret) {
		ret = LDAP_SUCCESS;
	}
	return ret;
}

/* Modify context structure destructor */
int modify_term(modify_context *mc,struct backend *be)
{
    ldbm_instance *inst = (ldbm_instance *) be->be_instance_info;

    slapi_mods_free(&mc->smods);
    /* Unlock and return entries */
    if (mc->old_entry)  {
        cache_unlock_entry(&inst->inst_cache, mc->old_entry);
        CACHE_RETURN( &(inst->inst_cache), &(mc->old_entry) );
        mc->old_entry= NULL;
    }

    CACHE_RETURN(&(inst->inst_cache), &(mc->new_entry));
    mc->new_entry= NULL;
    return 0;
}

/* Modify context structure member to switch entries in the cache */
int modify_switch_entries(modify_context *mc,backend *be)
{
	ldbm_instance *inst = (ldbm_instance *) be->be_instance_info;
	int ret = 0;
	if (mc->old_entry && mc->new_entry) {
		ret = cache_replace(&(inst->inst_cache), mc->old_entry, mc->new_entry);
		if (ret) {
			LDAPDebug(LDAP_DEBUG_CACHE, "modify_switch_entries: replacing %s with %s failed (%d)\n",
			          slapi_entry_get_dn(mc->old_entry->ep_entry), 
			          slapi_entry_get_dn(mc->new_entry->ep_entry), ret);
		}
	}
	return ret;
}

/*
 * Switch the new with the old(original) - undoing modify_switch_entries()
 * This expects modify_term() to be called next, as the old "new" entry
 * is now gone(replaced by the original entry).
 */
int
modify_unswitch_entries(modify_context *mc,backend *be)
{
	struct backentry *tmp_be;
	ldbm_instance *inst = (ldbm_instance *) be->be_instance_info;
	int ret = 0;

	if (mc->old_entry && mc->new_entry && 
	    cache_is_in_cache(&inst->inst_cache, mc->new_entry)) {
		/* switch the entries, and reset the new, new, entry */
		tmp_be = mc->new_entry;
		mc->new_entry = mc->old_entry;
		mc->new_entry->ep_state = 0;
		if (cache_has_otherref(&(inst->inst_cache), mc->new_entry)) {
			/* some other thread refers the entry */
			CACHE_RETURN(&(inst->inst_cache), &(mc->new_entry));
		} else {
			/* don't call CACHE_RETURN, that frees the entry!  */
			mc->new_entry->ep_refcnt = 0;
		}
		mc->old_entry = tmp_be;

		ret = cache_replace(&(inst->inst_cache), mc->old_entry, mc->new_entry);
		if (ret == 0) {
			/*
			 * The new entry was originally locked, so since we did the
			 * switch we need to unlock the "new" entry, and return the
			 * "old" one.  modify_term() will then return the "new" entry.
			 */
			cache_unlock_entry(&inst->inst_cache, mc->new_entry);
			cache_lock_entry(&inst->inst_cache, mc->old_entry);
		} else {
			LDAPDebug(LDAP_DEBUG_CACHE, "modify_unswitch_entries: replacing %s with %s failed (%d)\n",
			          slapi_entry_get_dn(mc->old_entry->ep_entry), 
			          slapi_entry_get_dn(mc->new_entry->ep_entry), ret);
		}
	}

	return ret;
}

/* This routine does that part of a modify operation which involves
   updating the on-disk data: updates idices, id2entry. 
   Copes properly with DB_LOCK_DEADLOCK. The caller must be able to cope with 
   DB_LOCK_DEADLOCK returned.
   The caller is presumed to proceed as follows: 
	Find the entry you want to modify;
	Lock it for modify;
	Make a copy of it; (call backentry_dup() )
	Apply modifications to the copy in memory (call entry_apply_mods() )
	begin transaction;
	Do any other mods to on-disk data you want
	Call this routine;
	Commit transaction;
   You pass it environment data: struct ldbminfo, pb (not sure why, but the vlv code seems to need it)
   the copy of the entry before modfication, the entry after modification;
   an LDAPMods array containing the modifications performed
*/
int modify_update_all(backend *be, Slapi_PBlock *pb,
					  modify_context *mc,
					  back_txn *txn)
{
	static char *function_name = "modify_update_all";
	Slapi_Operation *operation;
	int is_ruv = 0;				 /* True if the current entry is RUV */
	int retval = 0;

	if (pb) { /* pb could be NULL if it's called from import */
		slapi_pblock_get( pb, SLAPI_OPERATION, &operation );
		is_ruv = operation_is_flag_set(operation, OP_FLAG_REPL_RUV);
	}
	/*
	 * Update the ID to Entry index. 
	 * Note that id2entry_add replaces the entry, so the Entry ID stays the same.
	 */
	retval = id2entry_add_ext( be, mc->new_entry, txn, mc->attr_encrypt, NULL );
	if ( 0 != retval ) {
		if (DB_LOCK_DEADLOCK != retval)
		{
			ldbm_nasty(function_name,66,retval);
		}
		goto error;
	}
	retval = index_add_mods( be, slapi_mods_get_ldapmods_byref(mc->smods), mc->old_entry, mc->new_entry, txn );
	if ( 0 != retval ) {
		if (DB_LOCK_DEADLOCK != retval)
		{
			ldbm_nasty(function_name,65,retval);
		}
		goto error;
	}
	/*
	 * Remove the old entry from the Virtual List View indexes.
	 * Add the new entry to the Virtual List View indexes.
	 * Because the VLV code calls slapi_filter_test(), which requires a pb (why?),
	 * we allow the caller sans pb to get everything except vlv indexing.
	 */
	if (NULL != pb && !is_ruv) {
		retval= vlv_update_all_indexes(txn, be, pb, mc->old_entry, mc->new_entry);
		if ( 0 != retval ) {
			if (DB_LOCK_DEADLOCK != retval)
			{
				ldbm_nasty(function_name,64,retval);
			}
			goto error;
		}
	}
error:
	return retval;
}

/**
   Apply the mods to the ec entry.  Check for syntax, schema problems.
   Check for abandon.

   Return code:
   -1 - error - result code and message are set appropriately
   0 - successfully applied and checked
   1 - not an error - no mods to apply or op abandoned
 */
static int
modify_apply_check_expand(
	Slapi_PBlock *pb,
	Slapi_Operation *operation,
	LDAPMod **mods, /* list of mods to apply */
	struct backentry *e, /* original "before" entry */
	struct backentry *ec, /* "after" entry with mods applied */
	Slapi_Entry **postentry,
	int *ldap_result_code,
	char **ldap_result_message
)
{
	int rc = 0;
	int i;
	int repl_op;
	int change_entry = 0;
	Slapi_Mods smods = {0};
	CSN *csn = operation_get_csn(operation);

	slapi_pblock_get (pb, SLAPI_IS_REPLICATED_OPERATION, &repl_op);
	slapi_mods_init_byref( &smods, mods );

	if ( (change_entry = mods_have_effect (ec->ep_entry, &smods)) ) {
		*ldap_result_code = entry_apply_mods_wsi(ec->ep_entry, &smods, csn,
												 operation_is_flag_set(operation, OP_FLAG_REPLICATED));
		/*
		 * XXXmcs: it would be nice to get back an error message from
		 * the above call so we could pass it along to the client, e.g.,
		 * "duplicate value for attribute givenName."
		 */
	} else {
		Slapi_Entry *epostop = NULL;
		/* If the entry was not actually changed, we still need to
		 * set the SLAPI_ENTRY_POST_OP field in the pblock (post-op
		 * plugins expect that field to be present for all modify
		 * operations that return LDAP_SUCCESS).
		 */
		slapi_pblock_get ( pb, SLAPI_ENTRY_POST_OP, &epostop );
		slapi_entry_free ( epostop ); /* free existing one, if any */
		slapi_pblock_set ( pb, SLAPI_ENTRY_POST_OP, slapi_entry_dup( e->ep_entry ) );
		*postentry = NULL; /* to avoid free in main error cleanup code */
	}
	if ( !change_entry || *ldap_result_code != 0 ) {
		/* change_entry == 0 is not an error just a no-op */
		rc = change_entry ? -1 : 1;
		goto done;
	}

	/*
	 * If the objectClass attribute type was modified in any way, expand
	 * the objectClass values to reflect the inheritance hierarchy.
	 */
	for ( i = 0; (mods != NULL) && (mods[i] != NULL) && !repl_op; ++i ) {
		if ( 0 == strcasecmp( SLAPI_ATTR_OBJECTCLASS, mods[i]->mod_type )) {
			slapi_schema_expand_objectclasses( ec->ep_entry );
			break;
		}
	}

	/*
	 * We are about to pass the last abandon test, so from now on we are
	 * committed to finish this operation. Set status to "will complete"
	 * before we make our last abandon check to avoid race conditions in
	 * the code that processes abandon operations.
	 */
	operation->o_status = SLAPI_OP_STATUS_WILL_COMPLETE;
	if ( slapi_op_abandoned( pb ) ) {
		rc = 1;
		goto done;
	}

	/* multimaster replication can result in a schema violation,
	 * although the individual operations on each master were valid
	 * It is too late to resolve this. But we can check schema and
	 * add a replication conflict attribute.
	 */
	/* check that the entry still obeys the schema */
	if ((operation_is_flag_set(operation,OP_FLAG_ACTION_SCHEMA_CHECK)) &&
			slapi_entry_schema_check_ext( pb, ec->ep_entry, 1 ) != 0 ) {
		if(repl_op){
			Slapi_Attr *attr;
			Slapi_Mods smods;
			LDAPMod **lmods;
			if (slapi_entry_attr_find (ec->ep_entry, ATTR_NSDS5_REPLCONFLICT, &attr) == 0)
			{
				/* add value */ 
				Slapi_Value *val = slapi_value_new_string("Schema violation");
				slapi_attr_add_value(attr,val);
				slapi_value_free(&val);
			} else {
				/* Add new attribute */
				slapi_entry_add_string (ec->ep_entry, ATTR_NSDS5_REPLCONFLICT, "Schema violation");
			}
			/* the replconflict attribute is indexed and the index is built from the mods,
			 * so we need to extend the mods */
			slapi_pblock_get(pb, SLAPI_MODIFY_MODS, &lmods);
			slapi_mods_init_passin(&smods, lmods);
			slapi_mods_add_string (&smods, LDAP_MOD_ADD, ATTR_NSDS5_REPLCONFLICT, "Schema violation");
			lmods = slapi_mods_get_ldapmods_passout(&smods);
			slapi_pblock_set(pb, SLAPI_MODIFY_MODS, lmods);
			slapi_mods_done(&smods);
			
		} else {
			*ldap_result_code = LDAP_OBJECT_CLASS_VIOLATION;
			slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, ldap_result_message);
			rc = -1;
			goto done;
		}
	}

	if(!repl_op){
		/* check attribute syntax for the new values */
		if (slapi_mods_syntax_check(pb, mods, 0) != 0) {
			*ldap_result_code = LDAP_INVALID_SYNTAX;
			slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, ldap_result_message);
			rc = -1;
			goto done;
		}

		/*
		 * make sure the entry contains all values in the RDN.
		 * if not, the modification must have removed them.
		 */
		if ( ! slapi_entry_rdn_values_present( ec->ep_entry ) ) {
			*ldap_result_code= LDAP_NOT_ALLOWED_ON_RDN;
			rc = -1;
			goto done;
		}
	}

done:
	slapi_mods_done( &smods );

	return rc;
}

int
ldbm_back_modify( Slapi_PBlock *pb )
{
	backend *be;
	ldbm_instance *inst = NULL;
	struct ldbminfo		*li;
	struct backentry	*e = NULL, *ec = NULL;
	struct backentry	*original_entry = NULL, *tmpentry = NULL;
	Slapi_Entry		*postentry = NULL;
	LDAPMod			**mods = NULL;
	LDAPMod			**mods_original = NULL;
	Slapi_Mods smods = {0};
	back_txn txn;
	back_txnid		parent_txn;
	modify_context		ruv_c = {0};
	int			ruv_c_init = 0;
	int			retval = -1;
	char			*msg;
	char			*errbuf = NULL;
	int retry_count = 0;
	int disk_full = 0;
	int ldap_result_code= LDAP_SUCCESS;
	char *ldap_result_message= NULL;
	int rc = 0;
	Slapi_Operation *operation;
	entry_address *addr;
	int is_fixup_operation= 0;
	int is_ruv = 0;                 /* True if the current entry is RUV */
	CSN *opcsn = NULL;
	int repl_op;
	int opreturn = 0;
	int mod_count = 0;
	int not_an_error = 0;
	int fixup_tombstone = 0;

	slapi_pblock_get( pb, SLAPI_BACKEND, &be);
	slapi_pblock_get( pb, SLAPI_PLUGIN_PRIVATE, &li );
	slapi_pblock_get( pb, SLAPI_TARGET_ADDRESS, &addr );
	slapi_pblock_get( pb, SLAPI_MODIFY_MODS, &mods );
	slapi_pblock_get( pb, SLAPI_TXN, (void**)&parent_txn );
	slapi_pblock_get( pb, SLAPI_IS_REPLICATED_OPERATION, &repl_op);
	slapi_pblock_get( pb, SLAPI_OPERATION, &operation );

	fixup_tombstone = operation_is_flag_set(operation, OP_FLAG_TOMBSTONE_FIXUP);

	dblayer_txn_init(li,&txn); /* must do this before first goto error_return */
	/* the calls to perform searches require the parent txn if any
	   so set txn to the parent_txn until we begin the child transaction */
	if (parent_txn) {
		txn.back_txn_txn = parent_txn;
	} else {
		parent_txn = txn.back_txn_txn;
		slapi_pblock_set( pb, SLAPI_TXN, parent_txn );
	}

	if (NULL == operation)
	{
		ldap_result_code = LDAP_OPERATIONS_ERROR;
		goto error_return;
	}

	is_fixup_operation = operation_is_flag_set(operation, OP_FLAG_REPL_FIXUP);
	is_ruv = operation_is_flag_set(operation, OP_FLAG_REPL_RUV);
	inst = (ldbm_instance *) be->be_instance_info;

	if (NULL == addr)
	{
		goto error_return;
	}
	if (inst && inst->inst_ref_count) {
		slapi_counter_increment(inst->inst_ref_count);
	} else {
		LDAPDebug1Arg(LDAP_DEBUG_ANY,
		              "ldbm_modify: instance \"%s\" does not exist.\n",
		              inst ? inst->inst_name : "null instance");
		goto error_return;
	}

	/* no need to check the dn syntax as this is a replicated op */
	if(!repl_op){
		ldap_result_code = slapi_dn_syntax_check(pb, slapi_sdn_get_dn(addr->sdn), 1);
		if (ldap_result_code)
		{
			ldap_result_code = LDAP_INVALID_DN_SYNTAX;
			slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, &ldap_result_message);
			goto error_return;
		}
	}

	/* The dblock serializes writes to the database,
	 * which reduces deadlocking in the db code,
	 * which means that we run faster.
	 *
	 * But, this lock is re-enterant for the fixup
	 * operations that the URP code in the Replication
	 * plugin generates.
	 *
	 * SERIALLOCK is moved to dblayer_txn_begin along with exposing be
	 * transaction to plugins (see slapi_back_transaction_* APIs).
	 *
	if(SERIALLOCK(li) && !operation_is_flag_set(operation,OP_FLAG_REPL_FIXUP)) {
		dblayer_lock_backend(be);
		dblock_acquired= 1;
	}
	 */
	if ( MANAGE_ENTRY_BEFORE_DBLOCK(li)) {
		/* find and lock the entry we are about to modify */
		if ( (e = find_entry2modify( pb, be, addr, &txn )) == NULL ) {
			ldap_result_code= -1;
			goto error_return;	  /* error result sent by find_entry2modify() */
		}
	}

	txn.back_txn_txn = NULL; /* ready to create the child transaction */
	for (retry_count = 0; retry_count < RETRY_TIMES; retry_count++) {
		int cache_rc = 0;
		int new_mod_count = 0;
		if (txn.back_txn_txn && (txn.back_txn_txn != parent_txn)) {
			/* don't release SERIAL LOCK */
			dblayer_txn_abort_ext(li, &txn, PR_FALSE); 
			slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
			/*
			 * Since be_txn_preop functions could have modified the entry/mods,
			 * We need to grab the current mods, free them, and restore the
			 * originals.  Same thing for the entry.
			 */
			
			slapi_pblock_get(pb, SLAPI_MODIFY_MODS, &mods);
			ldap_mods_free(mods, 1);
			slapi_pblock_set(pb, SLAPI_MODIFY_MODS, copy_mods(mods_original));

			/* reset ec set cache in id2entry_add_ext */
			if (ec) {
				/* must duplicate ec before returning it to cache,
				 * which could free the entry. */
				if ( (tmpentry = backentry_dup( ec )) == NULL ) {
					ldap_result_code= LDAP_OPERATIONS_ERROR;
					goto error_return;
				}
				if (cache_is_in_cache(&inst->inst_cache, ec)) {
					CACHE_REMOVE(&inst->inst_cache, ec);
				}
				CACHE_RETURN(&inst->inst_cache, &ec);
				slapi_pblock_set( pb, SLAPI_MODIFY_EXISTING_ENTRY, original_entry->ep_entry );
				ec = original_entry;
				original_entry = tmpentry;
				tmpentry = NULL;
			}

			if (ruv_c_init) {
				/* reset the ruv txn stuff */
				modify_term(&ruv_c, be);
				ruv_c_init = 0;
			}

			LDAPDebug0Args(LDAP_DEBUG_BACKLDBM,
			               "Modify Retrying Transaction\n");
#ifndef LDBM_NO_BACKOFF_DELAY
			{
			PRIntervalTime interval;
			interval = PR_MillisecondsToInterval(slapi_rand() % 100);
			DS_Sleep(interval);
			}
#endif
		}

		/* Nothing above here modifies persistent store, everything after here is subject to the transaction */
		/* dblayer_txn_begin holds SERIAL lock, 
		 * which should be outside of locking the entry (find_entry2modify) */
		if (0 == retry_count) {
			/* First time, hold SERIAL LOCK */
			retval = dblayer_txn_begin(be, parent_txn, &txn);
		} else {
			/* Otherwise, no SERIAL LOCK */
			retval = dblayer_txn_begin_ext(li, parent_txn, &txn, PR_FALSE);
		}
		if (0 != retval) {
			if (LDBM_OS_ERR_IS_DISKFULL(retval)) disk_full = 1;
			ldap_result_code= LDAP_OPERATIONS_ERROR;
			goto error_return;
		}
		/* stash the transaction for plugins */
		slapi_pblock_set(pb, SLAPI_TXN, txn.back_txn_txn);

		if (0 == retry_count) { /* just once */
			if ( !MANAGE_ENTRY_BEFORE_DBLOCK(li)) {
				/* find and lock the entry we are about to modify */
				if ( (e = find_entry2modify( pb, be, addr, &txn )) == NULL ) {
					ldap_result_code= -1;
					goto error_return;	  /* error result sent by find_entry2modify() */
				}
			}
		
			if ( !is_fixup_operation && !fixup_tombstone)
			{
				if (!repl_op && slapi_entry_flag_is_set(e->ep_entry, SLAPI_ENTRY_FLAG_TOMBSTONE))
				{
					ldap_result_code = LDAP_UNWILLING_TO_PERFORM;
                			ldap_result_message = "Operation not allowed on tombstone entry.";
					slapi_log_error(SLAPI_LOG_FATAL, "ldbm_back_modify",
						"Attempt to modify a tombstone entry %s\n",
						slapi_sdn_get_dn(slapi_entry_get_sdn_const( e->ep_entry )));
					goto error_return;
				}
				opcsn = operation_get_csn (operation);
				if (NULL == opcsn && operation->o_csngen_handler)
				{
					/*
					 * Current op is a user request. Opcsn will be assigned
					 * if the dn is in an updatable replica.
					 */
					opcsn = entry_assign_operation_csn ( pb, e->ep_entry, NULL );
				}
				if (opcsn)
				{
					entry_set_maxcsn (e->ep_entry, opcsn);
				}
			}
		
			/* Save away a copy of the entry, before modifications */
			slapi_pblock_set( pb, SLAPI_ENTRY_PRE_OP, slapi_entry_dup( e->ep_entry ));
			
			if ( (ldap_result_code = plugin_call_acl_mods_access( pb, e->ep_entry, mods, &errbuf)) != LDAP_SUCCESS ) {
				ldap_result_message= errbuf;
				goto error_return;
			}
		
			/* create a copy of the entry and apply the changes to it */
			if ( (ec = backentry_dup( e )) == NULL ) {
				ldap_result_code= LDAP_OPERATIONS_ERROR;
				goto error_return;
			}
		
			if(!repl_op){
			    remove_illegal_mods(mods);
			}
		
			/* ec is the entry that our bepreop should get to mess with */
			slapi_pblock_set( pb, SLAPI_MODIFY_EXISTING_ENTRY, ec->ep_entry );
			slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
		
			opreturn = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_PRE_MODIFY_FN);
			if (opreturn ||
				(slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code) && ldap_result_code) ||
				(slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn) && opreturn)) {
				slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
				slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
				if (!ldap_result_code) {
					LDAPDebug0Args(LDAP_DEBUG_ANY, "ldbm_back_modify: SLAPI_PLUGIN_BE_PRE_MODIFY_FN "
						       "returned error but did not set SLAPI_RESULT_CODE\n");
					ldap_result_code = LDAP_OPERATIONS_ERROR;
				}
				if (SLAPI_PLUGIN_NOOP == opreturn) {
					not_an_error = 1;
					rc = opreturn = LDAP_SUCCESS;
				} else if (!opreturn) {
					opreturn = SLAPI_PLUGIN_FAILURE;
					slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
				}
				goto error_return;
			}
			/* The Plugin may have messed about with some of the PBlock parameters... ie. mods */
			slapi_pblock_get( pb, SLAPI_MODIFY_MODS, &mods );
		
			/* apply the mods, check for syntax, schema problems, etc. */
			if (modify_apply_check_expand(pb, operation, mods, e, ec, &postentry,
										  &ldap_result_code, &ldap_result_message)) {
				goto error_return;
			}
			/* the schema check could have added a repl conflict mod
			 * get the mods again */
			slapi_pblock_get( pb, SLAPI_MODIFY_MODS, &mods );
			slapi_mods_init_byref(&smods,mods);
			mod_count = slapi_mods_get_num_mods(&smods);
			/*
			 * Grab a copy of the mods and the entry in case the be_txn_preop changes
			 * the them.  If we have a failure, then we need to reset the mods to their
			 * their original state;
			 */
			mods_original = copy_mods(mods);
			if ( (original_entry = backentry_dup( ec )) == NULL ) {
				ldap_result_code= LDAP_OPERATIONS_ERROR;
				goto error_return;
			}
		} /* if (0 == retry_count) just once */

		/* call the transaction pre modify plugins just after creating the transaction */
		retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_PRE_MODIFY_FN);
		if (retval) {
			LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_PRE_MODIFY_FN plugin "
						   "returned error code %d\n", retval );
			slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
			slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
			if (SLAPI_PLUGIN_NOOP == retval) {
				not_an_error = 1;
				rc = retval = LDAP_SUCCESS;
			}
			if (!opreturn) {
				slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, ldap_result_code ? &ldap_result_code : &retval);
			}
			slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, &ldap_result_message);
			goto error_return;
		}

		/* the mods might have been changed, so get the latest */
		slapi_pblock_get( pb, SLAPI_MODIFY_MODS, &mods );

		/* make sure the betxnpreop did not alter any of the mods that
		   had already previously been applied */
		slapi_mods_done(&smods);
		slapi_mods_init_byref(&smods,mods);
		new_mod_count = slapi_mods_get_num_mods(&smods);
		if (new_mod_count < mod_count) {
			LDAPDebug2Args( LDAP_DEBUG_ANY, "Error: BE_TXN_PRE_MODIFY plugin has removed "
							"mods from the original list - mod count was [%d] now [%d] "
							"mods will not be applied - mods list changes must be done "
							"in the BE_PRE_MODIFY plugin, not the BE_TXN_PRE_MODIFY\n",
							mod_count, new_mod_count );
		} else if (new_mod_count > mod_count) { /* apply the new betxnpremod mods */
			/* apply the mods, check for syntax, schema problems, etc. */
			if (modify_apply_check_expand(pb, operation, &mods[mod_count], e, ec, &postentry,
										  &ldap_result_code, &ldap_result_message)) {
				goto error_return;
			}
		} /* else if new_mod_count == mod_count then betxnpremod plugin did nothing */
			
		/*
		 * Update the ID to Entry index. 
		 * Note that id2entry_add replaces the entry, so the Entry ID 
		 * stays the same.
		 */
		retval = id2entry_add_ext( be, ec, &txn, 1, &cache_rc ); 
		if (DB_LOCK_DEADLOCK == retval)
		{
			/* Abort and re-try */
			continue;
		}
		if (0 != retval) {
			LDAPDebug( LDAP_DEBUG_ANY, "id2entry_add failed, err=%d %s\n",
				   retval, (msg = dblayer_strerror( retval )) ? msg : "", 0 );
			if (LDBM_OS_ERR_IS_DISKFULL(retval)) disk_full = 1;
			MOD_SET_ERROR(ldap_result_code, LDAP_OPERATIONS_ERROR, retry_count);
			goto error_return;
		}
		retval = index_add_mods( be, mods, e, ec, &txn );
		if (DB_LOCK_DEADLOCK == retval)
		{
			/* Abort and re-try */
			continue;
		}
		if (0 != retval) {
			LDAPDebug( LDAP_DEBUG_ANY, "index_add_mods failed, err=%d %s\n",
				  retval, (msg = dblayer_strerror( retval )) ? msg : "", 0 );
			if (LDBM_OS_ERR_IS_DISKFULL(retval)) disk_full = 1;
			MOD_SET_ERROR(ldap_result_code, LDAP_OPERATIONS_ERROR, retry_count);
			goto error_return;
		}
		/*
		 * Remove the old entry from the Virtual List View indexes.
		 * Add the new entry to the Virtual List View indexes.
		 * If the entry is ruv, no need to update vlv.
		 */
		if (!is_ruv) {
			retval= vlv_update_all_indexes(&txn, be, pb, e, ec);
			if (DB_LOCK_DEADLOCK == retval)
			{
				/* Abort and re-try */
				continue;
			}
			if (0 != retval) {
				LDAPDebug( LDAP_DEBUG_ANY, 
					"vlv_update_index failed, err=%d %s\n",
					retval, (msg = dblayer_strerror( retval )) ? msg : "", 0 );
				if (LDBM_OS_ERR_IS_DISKFULL(retval)) disk_full = 1;
				MOD_SET_ERROR(ldap_result_code, 
							  LDAP_OPERATIONS_ERROR, retry_count);
				goto error_return;
			}

		}

		if (!is_ruv && !is_fixup_operation && !NO_RUV_UPDATE(li)) {
			ruv_c_init = ldbm_txn_ruv_modify_context( pb, &ruv_c );
			if (-1 == ruv_c_init) {
				LDAPDebug( LDAP_DEBUG_ANY,
					"ldbm_back_modify: ldbm_txn_ruv_modify_context "
					"failed to construct RUV modify context\n",
					0, 0, 0);
				ldap_result_code= LDAP_OPERATIONS_ERROR;
				retval = 0;
				goto error_return;
			}
		}

		if (ruv_c_init) {
			retval = modify_update_all( be, pb, &ruv_c, &txn );
			if (DB_LOCK_DEADLOCK == retval) {
				/* Abort and re-try */
				continue;
			}
			if (0 != retval) {
				LDAPDebug( LDAP_DEBUG_ANY,
					"modify_update_all failed, err=%d %s\n", retval,
					(msg = dblayer_strerror( retval )) ? msg : "", 0 );
				if (LDBM_OS_ERR_IS_DISKFULL(retval))
					disk_full = 1;
				ldap_result_code= LDAP_OPERATIONS_ERROR;
				goto error_return;
			}
		}

		if (0 == retval) {
			break;
		}
	}
	if (retry_count == RETRY_TIMES) {
		LDAPDebug( LDAP_DEBUG_ANY, "Retry count exceeded in modify\n", 0, 0, 0 );
	   	ldap_result_code= LDAP_BUSY;
		goto error_return;
	}

	if (ruv_c_init) {
		if (modify_switch_entries(&ruv_c, be) != 0 ) {
			ldap_result_code= LDAP_OPERATIONS_ERROR;
			LDAPDebug( LDAP_DEBUG_ANY,
				"ldbm_back_modify: modify_switch_entries failed\n", 0, 0, 0);
			goto error_return;
		}
	}
	
	if (cache_replace( &inst->inst_cache, e, ec ) != 0 ) {
		MOD_SET_ERROR(ldap_result_code, LDAP_OPERATIONS_ERROR, retry_count);
		goto error_return;
	}
	/* e uncached */
	/* we must return both e (which has been deleted) and new entry ec to cache */
	/* cache_replace removes e from the cache hash tables */
	cache_unlock_entry( &inst->inst_cache, e );
	CACHE_RETURN( &inst->inst_cache, &e );
	/* lock new entry in cache to prevent usage until we are complete */
	cache_lock_entry( &inst->inst_cache, ec );
	postentry = slapi_entry_dup( ec->ep_entry );
	slapi_pblock_set( pb, SLAPI_ENTRY_POST_OP, postentry );

	/* invalidate virtual cache */
	ec->ep_entry->e_virtual_watermark = 0;

	/* 
	 * LP Fix of crash when the commit will fail:
	 * If the commit fail, the common error path will
	 * try to unlock the entry again and crash (PR_ASSERT
	 * in debug mode.
	 * By just setting e to NULL, we avoid this. It's OK since
	 * we don't use e after that in the normal case.
	 */
	e = NULL;
	
	/* call the transaction post modify plugins just before the commit */
	if ((retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_POST_MODIFY_FN))) {
		LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_POST_MODIFY_FN plugin "
					   "returned error code %d\n", retval );
		if (!ldap_result_code) {
			slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
		}
		if (!opreturn) {
			slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
		}
		if (!opreturn) {
			slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, ldap_result_code ? &ldap_result_code : &retval);
		}
		slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, &ldap_result_message);
		goto error_return;
	}

	/* Release SERIAL LOCK */
	retval = dblayer_txn_commit(be, &txn);
	/* after commit - txn is no longer valid - replace SLAPI_TXN with parent */
	slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
	if (0 != retval) {
		if (LDBM_OS_ERR_IS_DISKFULL(retval)) disk_full = 1;
		ldap_result_code= LDAP_OPERATIONS_ERROR;
		goto error_return;
	}

	rc= 0;
	goto common_return;

error_return:
	if ( postentry != NULL ) 
	{
		slapi_entry_free( postentry );
		postentry = NULL;
		slapi_pblock_set( pb, SLAPI_ENTRY_POST_OP, NULL );
	}
	if (retval == DB_RUNRECOVERY) {
	  dblayer_remember_disk_filled(li);
	  ldbm_nasty("Modify",81,retval);
	  disk_full = 1;
	}

	if (disk_full) {
	    rc= return_on_disk_full(li);
	} else {
		if (txn.back_txn_txn && (txn.back_txn_txn != parent_txn)) {
			/* make sure SLAPI_RESULT_CODE and SLAPI_PLUGIN_OPRETURN are set */
			int val = 0;
			slapi_pblock_get(pb, SLAPI_RESULT_CODE, &val);
			if (!val) {
				if (!ldap_result_code) {
					ldap_result_code = LDAP_OPERATIONS_ERROR;
				}
				slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);
			}
			slapi_pblock_get( pb, SLAPI_PLUGIN_OPRETURN, &val );
			if (!val) {
				opreturn = -1;
				slapi_pblock_set( pb, SLAPI_PLUGIN_OPRETURN, &opreturn );
			}
			/* call the transaction post modify plugins just before the abort */
			/* plugins called before abort should check for the OPRETURN or RESULT_CODE
			   and skip processing if they don't want do anything - some plugins that
			   keep track of a counter (usn, dna) may want to "rollback" the counter
			   in this case */
			if ((retval = plugin_call_plugins(pb, SLAPI_PLUGIN_BE_TXN_POST_MODIFY_FN))) {
				LDAPDebug1Arg( LDAP_DEBUG_TRACE, "SLAPI_PLUGIN_BE_TXN_POST_MODIFY_FN plugin "
							   "returned error code %d\n", retval );
				slapi_pblock_get(pb, SLAPI_RESULT_CODE, &ldap_result_code);
				slapi_pblock_get(pb, SLAPI_PB_RESULT_TEXT, &ldap_result_message);
				slapi_pblock_get(pb, SLAPI_PLUGIN_OPRETURN, &opreturn);
				if (!opreturn) {
					slapi_pblock_set(pb, SLAPI_PLUGIN_OPRETURN, ldap_result_code ? &ldap_result_code : &retval);
				}
			}

			/* It is safer not to abort when the transaction is not started. */
			/* Release SERIAL LOCK */
			dblayer_txn_abort(be, &txn); /* abort crashes in case disk full */
			/* txn is no longer valid - reset the txn pointer to the parent */
			slapi_pblock_set(pb, SLAPI_TXN, parent_txn);
		}
		if (!not_an_error) {
			rc = SLAPI_FAIL_GENERAL;
		}
	}

	/* if ec is in cache, remove it, then add back e if we still have it */
	if (inst && cache_is_in_cache(&inst->inst_cache, ec)) {
		CACHE_REMOVE( &inst->inst_cache, ec );
		/* if ec was in cache, e was not - add back e */
		if (e) {
			if (CACHE_ADD( &inst->inst_cache, e, NULL ) < 0) {
				LDAPDebug1Arg(LDAP_DEBUG_CACHE, "ldbm_modify: CACHE_ADD %s failed\n",
				              slapi_entry_get_dn(e->ep_entry));
			}
		}
	}

common_return:
	slapi_mods_done(&smods);
	
	if (inst) {
		if (cache_is_in_cache(&inst->inst_cache, ec)) {
			cache_unlock_entry(&inst->inst_cache, ec);
		} else if (e) {
			/* if ec was not in cache, cache_replace was not done.
			 * i.e., e was not unlocked. */
			cache_unlock_entry(&inst->inst_cache, e);
			CACHE_RETURN(&inst->inst_cache, &e);
		}
		CACHE_RETURN(&inst->inst_cache, &ec);
		if (inst->inst_ref_count) {
			slapi_counter_decrement(inst->inst_ref_count);
		}
	}

	/* result code could be used in the bepost plugin functions. */
	slapi_pblock_set(pb, SLAPI_RESULT_CODE, &ldap_result_code);

	/* The bepostop is called even if the operation fails. */
	if (!disk_full)
		plugin_call_plugins (pb, SLAPI_PLUGIN_BE_POST_MODIFY_FN);

	if (ruv_c_init) {
		modify_term(&ruv_c, be);
	}

	if(ldap_result_code!=-1)
	{
		if (not_an_error) {
			/* This is mainly used by urp.  Solved conflict is not an error.
			 * And we don't want the supplier to halt sending the updates. */
			ldap_result_code = LDAP_SUCCESS;
		}
		slapi_send_ldap_result( pb, ldap_result_code, NULL, ldap_result_message, 0, NULL );
	}

	/* free our backups */
	ldap_mods_free(mods_original, 1);
	backentry_free(&original_entry);
	backentry_free(&tmpentry);
	slapi_ch_free_string(&errbuf);

	return rc;
}

/* Function removes mods which are not allowed over-the-wire */
static void
remove_illegal_mods(LDAPMod **mods)
{
	int		i, j;
	LDAPMod		*tmp;

	/* remove any attempts by the user to modify these attrs */
	for ( i = 0; (mods != NULL) && (mods[i] != NULL); i++ ) {
		if ( strcasecmp( mods[i]->mod_type, numsubordinates ) == 0
		    || strcasecmp( mods[i]->mod_type, hassubordinates ) == 0 )
		{
			tmp = mods[i];
			for ( j = i; mods[j] != NULL; j++ ) {
				mods[j] = mods[j + 1];
			}
			slapi_ch_free( (void**)&(tmp->mod_type) );
			if ( tmp->mod_bvalues != NULL ) {
				ber_bvecfree( tmp->mod_bvalues );
			}
			slapi_ch_free( (void**)&tmp );
			i--;
		}
	}
}

/* A mod has no effect if it is trying to replace a non-existing
 * attribute with null value
 */ 
static int
mods_have_effect (Slapi_Entry *entry, Slapi_Mods *smods)
{
	LDAPMod *mod;
	Slapi_Attr *attr;
	int have_effect = 1;
	int j;

	/* Mods have effect if there is at least a non-replace mod or
	 * a non-null-value mod.
	 */
	for ( j = 0; j < smods->num_mods - 1; j++ ) {
		if ( (mod = smods->mods[j]) != NULL ) {
			if ( ((mod->mod_op & LDAP_MOD_REPLACE) == 0) ||
				 (mod->mod_vals.modv_bvals &&
				  strcasecmp (mod->mod_type, "modifiersname") &&
				  strcasecmp (mod->mod_type, "modifytime") ) ) {
				goto done;
			}
		}
	}

	if ( entry && entry->e_sdn.dn ) {
		for ( j = 0; j < smods->num_mods - 1; j++ ) {
			if ((mod = smods->mods[j]) != NULL) {
				for ( attr = entry->e_attrs; attr; attr = attr->a_next ) {
					/* Mods have effect if at least a null-value-mod is
					 * to actually remove an existing attribute
					 */
					if ( strcasecmp ( mod->mod_type, attr->a_type ) == 0 ) {
						have_effect = 1; /* found one - mod has effect */
						goto done;
					}
					/* this mod type was not found in the entry - if we don't
					   find one of the other mod types, or if there are no more
					   mod types to look for, this mod does not apply */
					have_effect = 0;
				}
			}
		}
	}

done:

	/* Return true would let the flow continue along the old path before
	 * this function was added
	 */
	return have_effect;
}