/* dyngroup.c - Demonstration of overlay code */
/* $OpenLDAP$ */
/*
 * Copyright 2003 The OpenLDAP Foundation, All Rights Reserved.
 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
 */
/*
 * Copyright 2003, Howard Chu, All rights reserved. <hyc@symas.com>
 * 
 * Permission is granted to anyone to use this software for any purpose
 * on any computer system, and to alter it and redistribute it, subject
 * to the following restrictions:
 * 
 * 1. The author is not responsible for the consequences of use of this
 *    software, no matter how awful, even if they arise from flaws in it.
 * 
 * 2. The origin of this software must not be misrepresented, either by
 *    explicit claim or by omission.  Since few users ever read sources,
 *    credits should appear in the documentation.
 * 
 * 3. Altered versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.  Since few users
 *    ever read sources, credits should appear in the documentation.
 * 
 * 4. This notice may not be removed or altered.
 */

#include "portable.h"

#include <stdio.h>

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

#include "slap.h"

/* This overlay extends the Compare operation to detect members of a
 * dynamic group. It has no effect on any other operations. It must
 * be configured with a pair of attributes to trigger on, e.g.
 *	attrpair member memberURL
 * will cause compares on "member" to trigger a compare on "memberURL".
 */

typedef struct adpair {
	struct adpair *ap_next;
	AttributeDescription *ap_mem;
	AttributeDescription *ap_uri;
} adpair;

static int
dyngroup_response( Operation *op, SlapReply *rs )
{
	slap_overinst *on = (slap_overinst *) op->o_bd->bd_info;
	adpair *ap = on->on_bi.bi_private;

	/* If we've been configured and the current response is
	 * what we're looking for...
	 */
	if ( ap && op->o_tag == LDAP_REQ_COMPARE &&
		rs->sr_err == LDAP_NO_SUCH_ATTRIBUTE ) {

		for (;ap;ap=ap->ap_next) {
			if ( op->oq_compare.rs_ava->aa_desc == ap->ap_mem ) {
				/* This compare is for one of the attributes we're
				 * interested in. We'll use slapd's existing dyngroup
				 * evaluator to get the answer we want.
				 */
				int cache = op->o_do_not_cache;
				
				op->o_do_not_cache = 1;
				if ( backend_group( op, NULL, &op->o_req_ndn,
					&op->oq_compare.rs_ava->aa_value, NULL, ap->ap_uri ) == 0 )
					rs->sr_err = LDAP_COMPARE_TRUE;
				op->o_do_not_cache = cache;
				break;
			}
		}
	}
	/* Default is to just fall through to the normal processing */
	return SLAP_CB_CONTINUE;
}

static int dyngroup_config(
    BackendDB	*be,
    const char	*fname,
    int		lineno,
    int		argc,
    char	**argv
)
{
	slap_overinst *on = (slap_overinst *) be->bd_info;
	adpair ap = { NULL, NULL, NULL }, *a2;

	if ( strcasecmp( argv[0], "attrpair" ) == 0 ) {
		const char *text;
		if ( argc != 3 ) {
			Debug( LDAP_DEBUG_ANY,
		"%s: line %d: attribute description missing in \"attrpair <member-attribute> <URL-attribute>\" line.\n",
			fname, lineno, 0 );
		    	return( 1 );
		}
		if ( slap_str2ad( argv[1], &ap.ap_mem, &text ) ) {
			Debug( LDAP_DEBUG_ANY,
		"%s: line %d: attribute description unknown \"attrpair\" line: %s.\n",
			fname, lineno, text );
			return( 1 );
		}
		if ( slap_str2ad( argv[2], &ap.ap_uri, &text ) ) {
			Debug( LDAP_DEBUG_ANY,
		"%s: line %d: attribute description unknown \"attrpair\" line: %s.\n",
			fname, lineno, text );
			return( 1 );
		}
		/* The on->on_bi.bi_private pointer can be used for
		 * anything this instance of the overlay needs.
		 */

		a2 = ch_malloc( sizeof(adpair) );
		a2->ap_next = on->on_bi.bi_private;
		a2->ap_mem = ap.ap_mem;
		a2->ap_uri = ap.ap_uri;
		on->on_bi.bi_private = a2;
	}
	return 0;
}

static int
dyngroup_close(
	BackendDB *be
)
{
	slap_overinst *on = (slap_overinst *) be->bd_info;
	adpair *ap, *a2;

	for ( ap = on->on_bi.bi_private; ap; ap = a2 ) {
		a2 = ap->ap_next;
		ch_free( ap );
	}
	return 0;
}

static slap_overinst dyngroup;

/* This overlay is set up for dynamic loading via moduleload. For static
 * configuration, you'll need to arrange for the slap_overinst to be
 * initialized and registered by some other function inside slapd.
 */

int init_module(int argc, char *argv[]) {
	dyngroup.on_bi.bi_type = "dyngroup";
	dyngroup.on_bi.bi_db_config = dyngroup_config;
	dyngroup.on_bi.bi_db_close = dyngroup_close;
	dyngroup.on_response = dyngroup_response;

	return overlay_register( &dyngroup );
}