1/*	$NetBSD: usn.c,v 1.2 2021/08/14 16:14:54 christos Exp $	*/
2
3/* usn.c - Maintain Microsoft-style Update Sequence Numbers */
4/* $OpenLDAP$ */
5/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
6 *
7 * Copyright 2007-2021 The OpenLDAP Foundation.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted only as authorized by the OpenLDAP
12 * Public License.
13 *
14 * A copy of this license is available in the file LICENSE in the
15 * top-level directory of the distribution or, alternatively, at
16 * <http://www.OpenLDAP.org/license.html>.
17 */
18/* ACKNOWLEDGEMENTS:
19 * This work was initially developed by Howard Chu for inclusion in
20 * OpenLDAP Software.
21 */
22
23#include <sys/cdefs.h>
24__RCSID("$NetBSD: usn.c,v 1.2 2021/08/14 16:14:54 christos Exp $");
25
26#include "portable.h"
27
28#ifdef SLAPD_OVER_USN
29
30#include <stdio.h>
31
32#include <ac/string.h>
33#include <ac/socket.h>
34
35#include "slap.h"
36#include "slap-config.h"
37
38/* This overlay intercepts write operations and adds a Microsoft-style
39 * USN to the target entry.
40 */
41
42typedef struct usn_info {
43	int ui_current;
44	ldap_pvt_thread_mutex_t ui_mutex;
45} usn_info_t;
46
47static AttributeDescription *ad_usnCreated, *ad_usnChanged;
48
49static struct {
50	char *desc;
51	AttributeDescription **adp;
52} as[] = {
53	{ "( 1.2.840.113556.1.2.19 "
54	    "NAME 'uSNCreated' "
55	    "SYNTAX '1.2.840.113556.1.4.906' "
56		"SINGLE-VALUE "
57		"NO-USER-MODIFICATION )",
58		&ad_usnCreated },
59	{ "( 1.2.840.113556.1.2.120 "
60		"NAME 'uSNChanged' "
61		"SYNTAX '1.2.840.113556.1.4.906' "
62		"SINGLE-VALUE "
63		"NO-USER-MODIFICATION )",
64		&ad_usnChanged },
65	{ NULL }
66};
67
68static int
69usn_func( Operation *op, SlapReply *rs )
70{
71	slap_overinst		*on = (slap_overinst *) op->o_bd->bd_info;
72	usn_info_t		*ui = on->on_bi.bi_private;
73	int my_usn;
74	char intbuf[64];
75	struct berval bv[2];
76
77	ldap_pvt_thread_mutex_lock( &ui->ui_mutex );
78	ui->ui_current++;
79	my_usn = ui->ui_current;
80	ldap_pvt_thread_mutex_unlock( &ui->ui_mutex );
81
82	BER_BVZERO(&bv[1]);
83	bv[0].bv_val = intbuf;
84	bv[0].bv_len = snprintf( intbuf, sizeof(intbuf), "%d", my_usn );
85	switch(op->o_tag) {
86	case LDAP_REQ_ADD:
87		attr_merge( op->ora_e, ad_usnCreated, bv, NULL );
88		attr_merge( op->ora_e, ad_usnChanged, bv, NULL );
89		break;
90	case LDAP_REQ_DELETE:
91		/* Probably need to update root usnLastObjRem */
92		break;
93	default: {
94		/* Modify, ModDN */
95		Modifications *ml, *mod = ch_calloc( sizeof( Modifications ), 1 );
96		for ( ml = op->orm_modlist; ml && ml->sml_next; ml = ml->sml_next );
97		ml->sml_next = mod;
98		mod->sml_desc = ad_usnChanged;
99		mod->sml_numvals = 1;
100		value_add_one( &mod->sml_values, &bv[0] );
101		mod->sml_nvalues = NULL;
102		mod->sml_op = LDAP_MOD_REPLACE;
103		mod->sml_flags = 0;
104		mod->sml_next = NULL;
105		break;
106		}
107	}
108	return SLAP_CB_CONTINUE;
109}
110
111static int
112usn_operational(
113	Operation *op,
114	SlapReply *rs )
115{
116	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
117	usn_info_t		*ui = (usn_info_t *)on->on_bi.bi_private;
118
119	if ( rs->sr_entry &&
120		dn_match( &rs->sr_entry->e_nname, op->o_bd->be_nsuffix )) {
121
122		if ( SLAP_OPATTRS( rs->sr_attr_flags ) ||
123			ad_inlist( ad_usnChanged, rs->sr_attrs )) {
124			Attribute *a, **ap = NULL;
125			char intbuf[64];
126			struct berval bv;
127			int my_usn;
128
129			for ( a=rs->sr_entry->e_attrs; a; a=a->a_next ) {
130				if ( a->a_desc == ad_usnChanged )
131					break;
132			}
133
134			if ( !a ) {
135				for ( ap = &rs->sr_operational_attrs; *ap;
136					ap=&(*ap)->a_next );
137
138					a = attr_alloc( ad_usnChanged );
139					*ap = a;
140				}
141
142			if ( !ap ) {
143				if ( rs_entry2modifiable( op,rs, on )) {
144					a = attr_find( rs->sr_entry->e_attrs,
145						ad_usnChanged );
146				}
147				ber_bvarray_free( a->a_vals );
148				a->a_vals = NULL;
149				a->a_numvals = 0;
150			}
151			ldap_pvt_thread_mutex_lock( &ui->ui_mutex );
152			my_usn = ui->ui_current;
153			ldap_pvt_thread_mutex_unlock( &ui->ui_mutex );
154			bv.bv_len = snprintf( intbuf, sizeof(intbuf), "%d", my_usn );
155			bv.bv_val = intbuf;
156			attr_valadd( a, &bv, NULL, 1 );
157		}
158	}
159	return SLAP_CB_CONTINUE;
160}
161
162/* Read the old USN from the underlying DB. This code is
163 * stolen from the syncprov overlay.
164 */
165static int
166usn_db_open(
167	BackendDB *be,
168	ConfigReply *cr)
169{
170	slap_overinst   *on = (slap_overinst *) be->bd_info;
171	usn_info_t *ui = (usn_info_t *)on->on_bi.bi_private;
172
173	Connection conn = { 0 };
174	OperationBuffer opbuf;
175	Operation *op;
176	Entry *e = NULL;
177	Attribute *a;
178	int rc;
179	void *thrctx = NULL;
180
181	thrctx = ldap_pvt_thread_pool_context();
182	connection_fake_init( &conn, &opbuf, thrctx );
183	op = &opbuf.ob_op;
184	op->o_bd = be;
185	op->o_dn = be->be_rootdn;
186	op->o_ndn = be->be_rootndn;
187
188	rc = overlay_entry_get_ov( op, be->be_nsuffix, NULL,
189		slap_schema.si_ad_contextCSN, 0, &e, on );
190
191	if ( e ) {
192		a = attr_find( e->e_attrs, ad_usnChanged );
193		if ( a ) {
194			ui->ui_current = atoi( a->a_vals[0].bv_val );
195		}
196		overlay_entry_release_ov( op, e, 0, on );
197	}
198	return 0;
199}
200
201static int
202usn_db_init(
203	BackendDB *be,
204	ConfigReply *cr
205)
206{
207	slap_overinst	*on = (slap_overinst *)be->bd_info;
208	usn_info_t	*ui;
209
210	if ( SLAP_ISGLOBALOVERLAY( be ) ) {
211		Debug( LDAP_DEBUG_ANY,
212			"usn must be instantiated within a database.\n" );
213		return 1;
214	}
215
216	ui = ch_calloc(1, sizeof(usn_info_t));
217	ldap_pvt_thread_mutex_init( &ui->ui_mutex );
218	on->on_bi.bi_private = ui;
219	return 0;
220}
221
222static int
223usn_db_close(
224	BackendDB *be,
225	ConfigReply *cr
226)
227{
228	slap_overinst	*on = (slap_overinst *)be->bd_info;
229	usn_info_t	*ui = on->on_bi.bi_private;
230	Connection conn = {0};
231	OperationBuffer opbuf;
232	Operation *op;
233	SlapReply rs = {REP_RESULT};
234	void *thrctx;
235
236	Modifications mod;
237	slap_callback cb = {0};
238	char intbuf[64];
239	struct berval bv[2];
240
241	thrctx = ldap_pvt_thread_pool_context();
242	connection_fake_init( &conn, &opbuf, thrctx );
243	op = &opbuf.ob_op;
244	op->o_bd = be;
245	BER_BVZERO( &bv[1] );
246	bv[0].bv_len = snprintf( intbuf, sizeof(intbuf), "%d", ui->ui_current );
247	bv[0].bv_val = intbuf;
248	mod.sml_numvals = 1;
249	mod.sml_values = bv;
250	mod.sml_nvalues = NULL;
251	mod.sml_desc = ad_usnChanged;
252	mod.sml_op = LDAP_MOD_REPLACE;
253	mod.sml_flags = 0;
254	mod.sml_next = NULL;
255
256	cb.sc_response = slap_null_cb;
257	op->o_tag = LDAP_REQ_MODIFY;
258	op->o_callback = &cb;
259	op->orm_modlist = &mod;
260	op->orm_no_opattrs = 1;
261	op->o_dn = be->be_rootdn;
262	op->o_ndn = be->be_rootndn;
263	op->o_req_dn = op->o_bd->be_suffix[0];
264	op->o_req_ndn = op->o_bd->be_nsuffix[0];
265	op->o_bd->bd_info = on->on_info->oi_orig;
266	op->o_managedsait = SLAP_CONTROL_NONCRITICAL;
267	op->o_no_schema_check = 1;
268	op->o_bd->be_modify( op, &rs );
269	if ( mod.sml_next != NULL ) {
270		slap_mods_free( mod.sml_next, 1 );
271	}
272	return 0;
273}
274
275static int
276usn_db_destroy(
277	BackendDB *be,
278	ConfigReply *cr
279)
280{
281	slap_overinst	*on = (slap_overinst *)be->bd_info;
282	usn_info_t	*ui = on->on_bi.bi_private;
283
284	ldap_pvt_thread_mutex_destroy( &ui->ui_mutex );
285	ch_free( ui );
286	on->on_bi.bi_private = NULL;
287	return 0;
288}
289
290/* This overlay is set up for dynamic loading via moduleload. For static
291 * configuration, you'll need to arrange for the slap_overinst to be
292 * initialized and registered by some other function inside slapd.
293 */
294
295static slap_overinst usn;
296
297int
298usn_init( void )
299{
300	int i, code;
301
302	memset( &usn, 0, sizeof( slap_overinst ) );
303	usn.on_bi.bi_type = "usn";
304	usn.on_bi.bi_flags = SLAPO_BFLAG_SINGLE;
305	usn.on_bi.bi_db_init = usn_db_init;
306	usn.on_bi.bi_db_destroy = usn_db_destroy;
307	usn.on_bi.bi_db_open = usn_db_open;
308	usn.on_bi.bi_db_close = usn_db_close;
309
310	usn.on_bi.bi_op_modify = usn_func;
311	usn.on_bi.bi_op_modrdn = usn_func;
312	usn.on_bi.bi_op_add = usn_func;
313	usn.on_bi.bi_op_delete = usn_func;
314	usn.on_bi.bi_operational = usn_operational;
315
316	for ( i = 0; as[i].desc; i++ ) {
317		code = register_at( as[i].desc, as[i].adp, 0 );
318		if ( code ) {
319			Debug( LDAP_DEBUG_ANY,
320				"usn_init: register_at #%d failed\n", i );
321			return code;
322		}
323	}
324	return overlay_register( &usn );
325}
326
327#if SLAPD_OVER_USN == SLAPD_MOD_DYNAMIC
328int
329init_module( int argc, char *argv[] )
330{
331	return usn_init();
332}
333#endif /* SLAPD_OVER_USN == SLAPD_MOD_DYNAMIC */
334
335#endif /* defined(SLAPD_OVER_USN) */
336