pcache.c

ldap服务器源码

/* $OpenLDAP: pkg/ldap/servers/slapd/overlays/pcache.c,v 1.41.2.17 2007/01/02 21:44:08 kurt Exp $ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 2003-2007 The OpenLDAP Foundation.
 * Portions Copyright 2003 IBM Corporation.
 * Portions Copyright 2003 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 Apurva Kumar for inclusion
 * in OpenLDAP Software and subsequently rewritten by Howard Chu.
 */

#include "portable.h"

#ifdef SLAPD_OVER_PROXYCACHE

#include <stdio.h>

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

#include "slap.h"
#include "lutil.h"
#include "ldap_rq.h"

#include "config.h"

/* query cache structs */
/* query */

typedef struct Query_s {
	Filter* 	filter; 	/* Search Filter */
	AttributeName* 	attrs;		/* Projected attributes */
	AttributeName*  save_attrs;	/* original attributes, saved for response */
	struct berval 	base; 		/* Search Base */
	int 		scope;		/* Search scope */
} Query;

/* struct representing a cached query */
typedef struct cached_query_s {
	Query 				query;		/* LDAP query */
	struct berval			q_uuid;		/* query identifier */
	int 				template_id;	/* template of the query */
	time_t 				expiry_time;	/* time till the query is considered valid */
	struct cached_query_s  		*next;  	/* next query in the template */
	struct cached_query_s  		*prev;  	/* previous query in the template */
	struct cached_query_s           *lru_up;	/* previous query in the LRU list */
	struct cached_query_s           *lru_down;	/* next query in the LRU list */
} CachedQuery;

/* struct representing a query template
 * e.g. template string = &(cn=)(mail=)
 */
typedef struct query_template_s {
	struct berval	querystr;	/* Filter string corresponding to the QT */
	int 		attr_set_index; /* determines the projected attributes */

	CachedQuery* 	query;	        /* most recent query cached for the template */
	CachedQuery* 	query_last;     /* oldest query cached for the template */

	int 		no_of_queries;  /* Total number of queries in the template */
	time_t		ttl;		/* TTL for the queries of this template */
	time_t		negttl;		/* TTL for negative results */
        ldap_pvt_thread_rdwr_t t_rwlock; /* Rd/wr lock for accessing queries in the template */
} QueryTemplate;

/*
 * Represents a set of projected attributes.
 */

struct attr_set {
	unsigned	flags;
#define	PC_CONFIGURED	(0x1)
#define	PC_REFERENCED	(0x2)
#define	PC_GOT_OC		(0x4)
	AttributeName*	attrs; 		/* specifies the set */
	int 		count;		/* number of attributes */
};

struct query_manager_s;

/* prototypes for functions for 1) query containment
 * 2) query addition, 3) cache replacement
 */
typedef CachedQuery * 	(QCfunc)(Operation *op, struct query_manager_s*, Query*, int );
typedef void  	(AddQueryfunc)(struct query_manager_s*, Query*, int, struct berval*);
typedef void	(CRfunc)(struct query_manager_s*, struct berval * );

/* LDAP query cache */
typedef struct query_manager_s {
	struct attr_set* 	attr_sets;		/* possible sets of projected attributes */
	QueryTemplate*	  	templates;		/* cacheable templates */

	CachedQuery*		lru_top;		/* top and bottom of LRU list */
	CachedQuery*		lru_bottom;

	ldap_pvt_thread_mutex_t		lru_mutex;	/* mutex for accessing LRU list */

	/* Query cache methods */
	QCfunc			*qcfunc;			/* Query containment*/
	CRfunc 			*crfunc;			/* cache replacement */
	AddQueryfunc	*addfunc;			/* add query */
} query_manager;

/* LDAP query cache manager */
typedef struct cache_manager_s {
	BackendDB	db;	/* underlying database */
	unsigned long	num_cached_queries; 		/* total number of cached queries */
	unsigned long   max_queries;			/* upper bound on # of cached queries */
	int 	numattrsets;			/* number of attribute sets */
	int 	numtemplates;			/* number of cacheable templates */
	int 	cur_entries;			/* current number of entries cached */
	int 	max_entries;			/* max number of entries cached */
        int     num_entries_limit;		/* max # of entries in a cacheable query */

	char	response_cb;			/* install the response callback
						 * at the tail of the callback list */
#define PCACHE_RESPONSE_CB_HEAD	0
#define PCACHE_RESPONSE_CB_TAIL	1

	time_t	cc_period;		/* interval between successive consistency checks (sec) */
	int	cc_paused;
	void	*cc_arg;

	ldap_pvt_thread_mutex_t		cache_mutex;

	query_manager*   qm;	/* query cache managed by the cache manager */
} cache_manager;

static int pcache_debug;

static AttributeDescription *ad_queryid;
static char *queryid_schema = "( 1.3.6.1.4.1.4203.666.1.12 NAME 'queryid' "
			"DESC 'list of queries the entry belongs to' "
			"EQUALITY octetStringMatch "
			"SYNTAX 1.3.6.1.4.1.1466.115.121.1.40{64} "
			"NO-USER-MODIFICATION USAGE directoryOperation )";

/* Return 1 for an added entry, else 0 */
static int
merge_entry(
	Operation		*op,
	Entry			*e,
	struct berval*		query_uuid )
{
	int		rc;
	Modifications* modlist = NULL;
	const char* 	text = NULL;
	Attribute		*attr;
	char			textbuf[SLAP_TEXT_BUFLEN];
	size_t			textlen = sizeof(textbuf);

	SlapReply sreply = {REP_RESULT};

	slap_callback cb = { NULL, slap_null_cb, NULL, NULL };

	attr = e->e_attrs;
	e->e_attrs = NULL;

	/* add queryid attribute */
	attr_merge_one( e, ad_queryid, query_uuid, NULL );

	/* append the attribute list from the fetched entry */
	e->e_attrs->a_next = attr;

	op->o_tag = LDAP_REQ_ADD;
	op->o_protocol = LDAP_VERSION3;
	op->o_callback = &cb;
	op->o_time = slap_get_time();
	op->o_do_not_cache = 1;

	op->ora_e = e;
	op->o_req_dn = e->e_name;
	op->o_req_ndn = e->e_nname;
	rc = op->o_bd->be_add( op, &sreply );

	if ( rc != LDAP_SUCCESS ) {
		if ( rc == LDAP_ALREADY_EXISTS ) {
			slap_entry2mods( e, &modlist, &text, textbuf, textlen );
			modlist->sml_op = LDAP_MOD_ADD;
			op->o_tag = LDAP_REQ_MODIFY;
			op->orm_modlist = modlist;
			op->o_bd->be_modify( op, &sreply );
			slap_mods_free( modlist, 1 );
		} else if ( rc == LDAP_REFERRAL ||
					rc == LDAP_NO_SUCH_OBJECT ) {
			syncrepl_add_glue( op, e );
			e = NULL;
			rc = 1;
		}
		if ( e ) {
			entry_free( e );
			rc = 0;
		}
	} else {
		be_entry_release_w( op, e );
		rc = 1;
	}

	return rc;
}

/* compare base and scope of incoming and cached queries */
static int base_scope_compare(
	struct berval* ndn_stored,
	struct berval* ndn_incoming,
	int scope_stored,
	int scope_incoming	)
{
	struct berval pdn_incoming = BER_BVNULL;

	if (scope_stored < scope_incoming)
		return 0;

	if ( !dnIsSuffix(ndn_incoming, ndn_stored))
		return 0;

	switch(scope_stored) {
	case LDAP_SCOPE_BASE:
		return (ndn_incoming->bv_len == ndn_stored->bv_len);

	case LDAP_SCOPE_ONELEVEL:
		switch(scope_incoming){
		case LDAP_SCOPE_BASE:
			dnParent(ndn_incoming, &pdn_incoming);
			return (pdn_incoming.bv_len == ndn_stored->bv_len);

		case LDAP_SCOPE_ONELEVEL:
			return (ndn_incoming->bv_len == ndn_stored->bv_len);

		default:
			return 0;
		}
	case LDAP_SCOPE_SUBTREE:
		return 1;
		break;
	default:
		return 0;
		break;
    }
}

/* add query on top of LRU list */
static void
add_query_on_top (query_manager* qm, CachedQuery* qc)
{
	CachedQuery* top = qm->lru_top;
	Query* q = (Query*)qc;

	qm->lru_top = qc;

	if (top)
		top->lru_up = qc;
	else
		qm->lru_bottom = qc;

	qc->lru_down = top;
	qc->lru_up = NULL;
	Debug( pcache_debug, "Base of added query = %s\n",
			q->base.bv_val, 0, 0 );
}

/* remove_query from LRU list */

static void
remove_query (query_manager* qm, CachedQuery* qc)
{
	CachedQuery* up;
	CachedQuery* down;

	if (!qc)
		return;

	up = qc->lru_up;
	down = qc->lru_down;

	if (!up)
		qm->lru_top = down;

	if (!down)
		qm->lru_bottom = up;

	if (down)
		down->lru_up = up;

	if (up)
		up->lru_down = down;

	qc->lru_up = qc->lru_down = NULL;
}

/* find and remove string2 from string1
 * from start if position = 1,
 * from end if position = 3,
 * from anywhere if position = 2
 * string1 is overwritten if position = 2.
 */

static int
find_and_remove(struct berval* ber1, struct berval* ber2, int position)
{
	int ret=0;

	if ( !ber2->bv_val )
		return 1;
	if ( !ber1->bv_val )
		return 0;

	switch( position ) {
	case 1:
		if ( ber1->bv_len >= ber2->bv_len && !memcmp( ber1->bv_val,
			ber2->bv_val, ber2->bv_len )) {
			ret = 1;
			ber1->bv_val += ber2->bv_len;
			ber1->bv_len -= ber2->bv_len;
		}
		break;
	case 2: {
		char *temp;
		ber1->bv_val[ber1->bv_len] = '\0';
		temp = strstr( ber1->bv_val, ber2->bv_val );
		if ( temp ) {
			strcpy( temp, temp+ber2->bv_len );
			ber1->bv_len -= ber2->bv_len;
			ret = 1;
		}
		break;
		}
	case 3:
		if ( ber1->bv_len >= ber2->bv_len &&
			!memcmp( ber1->bv_val+ber1->bv_len-ber2->bv_len, ber2->bv_val,
				ber2->bv_len )) {
			ret = 1;
			ber1->bv_len -= ber2->bv_len;
		}
		break;
	}
	return ret;
}


static struct berval*
merge_init_final(Operation *op, struct berval* init, struct berval* any,
	struct berval* final)
{
	struct berval* merged, *temp;
	int i, any_count, count;

	for (any_count=0; any && any[any_count].bv_val; any_count++)
		;

	count = any_count;

	if (init->bv_val)
		count++;
	if (final->bv_val)
		count++;

	merged = (struct berval*)op->o_tmpalloc( (count+1)*sizeof(struct berval),
		op->o_tmpmemctx );
	temp = merged;

	if (init->bv_val) {
		ber_dupbv_x( temp, init, op->o_tmpmemctx );
		temp++;
	}

	for (i=0; i<any_count; i++) {
		ber_dupbv_x( temp, any, op->o_tmpmemctx );
		temp++; any++;
	}

	if (final->bv_val){
		ber_dupbv_x( temp, final, op->o_tmpmemctx );
		temp++;
	}
	BER_BVZERO( temp );
	return merged;
}

/* Each element in stored must be found in incoming. Incoming is overwritten.
 */
static int
strings_containment(struct berval* stored, struct berval* incoming)
{
	struct berval* element;
	int k=0;
	int j, rc = 0;

	for ( element=stored; element->bv_val != NULL; element++ ) {
		for (j = k; incoming[j].bv_val != NULL; j++) {
			if (find_and_remove(&(incoming[j]), element, 2)) {
				k = j;
				rc = 1;
				break;
			}
			rc = 0;
		}
		if ( rc ) {
			continue;
		} else {
			return 0;
		}
	}
	return 1;
}

static int
substr_containment_substr(Operation *op, Filter* stored, Filter* incoming)
{
	int i;
	int rc = 0;

	struct berval init_incoming;
	struct berval final_incoming;
	struct berval *remaining_incoming = NULL;

	if ((!(incoming->f_sub_initial.bv_val) && (stored->f_sub_initial.bv_val))
	   || (!(incoming->f_sub_final.bv_val) && (stored->f_sub_final.bv_val)))
		return 0;

	init_incoming = incoming->f_sub_initial;
	final_incoming =  incoming->f_sub_final;

	if (find_and_remove(&init_incoming,
			&(stored->f_sub_initial), 1) && find_and_remove(&final_incoming,
			&(stored->f_sub_final), 3))
	{
		if (stored->f_sub_any == NULL) {
			rc = 1;
			goto final;
		}
		remaining_incoming = merge_init_final(op, &init_incoming,
						incoming->f_sub_any, &final_incoming);
		rc = strings_containment(stored->f_sub_any, remaining_incoming);
		ber_bvarray_free_x( remaining_incoming, op->o_tmpmemctx );
	}
final:
	return rc;
}

static int
substr_containment_equality(Operation *op, Filter* stored, Filter* incoming)
{
	struct berval incoming_val[2];
	int rc = 0;

	incoming_val[1] = incoming->f_av_value;

	if (find_and_remove(incoming_val+1,
			&(stored->f_sub_initial), 1) && find_and_remove(incoming_val+1,
			&(stored->f_sub_final), 3)) {
		if (stored->f_sub_any == NULL){
			rc = 1;
			goto final;
		}
		ber_dupbv_x( incoming_val, incoming_val+1, op->o_tmpmemctx );
		BER_BVZERO( incoming_val+1 );
		rc = strings_containment(stored->f_sub_any, incoming_val);
		op->o_tmpfree( incoming_val[0].bv_val, op->o_tmpmemctx );
	}
final:
	return rc;
}

/* check whether query is contained in any of
 * the cached queries in template template_index
 */
static CachedQuery *
query_containment(Operation *op, query_manager *qm,
		  Query *query,
		  int template_index)
{
	QueryTemplate* templa= qm->templates;
	CachedQuery* qc;
	Query* q;
	Filter* inputf = query->filter;
	struct berval* base = &(query->base);
	int scope = query->scope;
	int res=0;
	Filter* fs;
	Filter* fi;
	int ret, rc;
	const char* text;

	MatchingRule* mrule = NULL;
	if (inputf != NULL) {
		Debug( pcache_debug, "Lock QC index = %d\n",
				template_index, 0, 0 );
		ldap_pvt_thread_rdwr_rlock(&(templa[template_index].t_rwlock));
		for(qc=templa[template_index].query; qc != NULL; qc= qc->next) {
			q = (Query*)qc;
			if(base_scope_compare(&(q->base), base, q->scope, scope)) {
				fi = inputf;
				fs = q->filter;
				do {
					res=0;
					switch (fs->f_choice) {
					case LDAP_FILTER_EQUALITY:
						if (fi->f_choice == LDAP_FILTER_EQUALITY)
							mrule = fs->f_ava->aa_desc->ad_type->sat_equality;
						else
							ret = 1;
						break;
					case LDAP_FILTER_GE:
					case LDAP_FILTER_LE:
						mrule = fs->f_ava->aa_desc->ad_type->sat_ordering;
						break;
					default:
						mrule = NULL; 
					}
					if (mrule) {
						rc = value_match(&ret, fs->f_ava->aa_desc, mrule,
						 	SLAP_MR_VALUE_OF_ASSERTION_SYNTAX,
							&(fi->f_ava->aa_value),
							&(fs->f_ava->aa_value), &text);
						if (rc != LDAP_SUCCESS) {
							ldap_pvt_thread_rdwr_runlock(&(templa[template_index].t_rwlock));
							Debug( pcache_debug,
							"Unlock: Exiting QC index=%d\n",
							template_index, 0, 0 );
							return NULL;
						}
					}
					switch (fs->f_choice) {