Starting a collection of overlays

servers/slapd/overlays/README

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+# $OpenLDAP$
+
+This directory is still a work in progress. As such, no explicit makefile
+is provided.
+
+The overlays are meant to be built as dynamically loaded modules.
+To build a particular overlay, use commands of this form:
+
+	libtool --mode=compile cc -I../../../include -I.. -c dyngroup.c
+	libtool --mode=link cc -rpath /module/executable/path \
+		-module -o dyngroup.la dyngroup.lo
+
+To use the dyngroup overlay on a backend, set slapd.conf as follows:
+
+	moduleload /module/executable/path/dyngroup.la
+
+	database bdb
+	... (BDB configuration)
+	overlay dyngroup
+	attrpair member memberurl
+
+Replace "/module/executable/path" with the full pathname of the directory
+where the module will be installed.

servers/slapd/overlays/dyngroup.c

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+/* 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 );
+}