source: branches/samba-3.5.x/source4/ntvfs/common/notify.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 16.2 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 Copyright (C) Andrew Tridgell 2006
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18*/
19
20/*
21 this is the change notify database. It implements mechanisms for
22 storing current change notify waiters in a tdb, and checking if a
23 given event matches any of the stored notify waiiters.
24*/
25
26#include "includes.h"
27#include "system/filesys.h"
28#include "../tdb/include/tdb.h"
29#include "../lib/util/util_tdb.h"
30#include "messaging/messaging.h"
31#include "tdb_wrap.h"
32#include "lib/messaging/irpc.h"
33#include "librpc/gen_ndr/ndr_notify.h"
34#include "../lib/util/dlinklist.h"
35#include "ntvfs/common/ntvfs_common.h"
36#include "ntvfs/sysdep/sys_notify.h"
37#include "cluster/cluster.h"
38#include "param/param.h"
39
40struct notify_context {
41 struct tdb_wrap *w;
42 struct server_id server;
43 struct messaging_context *messaging_ctx;
44 struct notify_list *list;
45 struct notify_array *array;
46 int seqnum;
47 struct sys_notify_context *sys_notify_ctx;
48 struct smb_iconv_convenience *iconv_convenience;
49};
50
51
52struct notify_list {
53 struct notify_list *next, *prev;
54 void *private_data;
55 void (*callback)(void *, const struct notify_event *);
56 void *sys_notify_handle;
57 int depth;
58};
59
60#define NOTIFY_KEY "notify array"
61
62#define NOTIFY_ENABLE "notify:enable"
63#define NOTIFY_ENABLE_DEFAULT true
64
65static NTSTATUS notify_remove_all(struct notify_context *notify);
66static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
67 uint32_t msg_type, struct server_id server_id, DATA_BLOB *data);
68
69/*
70 destroy the notify context
71*/
72static int notify_destructor(struct notify_context *notify)
73{
74 messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
75 notify_remove_all(notify);
76 return 0;
77}
78
79/*
80 Open up the notify.tdb database. You should close it down using
81 talloc_free(). We need the messaging_ctx to allow for notifications
82 via internal messages
83*/
84struct notify_context *notify_init(TALLOC_CTX *mem_ctx, struct server_id server,
85 struct messaging_context *messaging_ctx,
86 struct loadparm_context *lp_ctx,
87 struct tevent_context *ev,
88 struct share_config *scfg)
89{
90 struct notify_context *notify;
91
92 if (share_bool_option(scfg, NOTIFY_ENABLE, NOTIFY_ENABLE_DEFAULT) != true) {
93 return NULL;
94 }
95
96 if (ev == NULL) {
97 return NULL;
98 }
99
100 notify = talloc(mem_ctx, struct notify_context);
101 if (notify == NULL) {
102 return NULL;
103 }
104
105 notify->w = cluster_tdb_tmp_open(notify, lp_ctx, "notify.tdb", TDB_SEQNUM);
106 if (notify->w == NULL) {
107 talloc_free(notify);
108 return NULL;
109 }
110
111 notify->server = server;
112 notify->messaging_ctx = messaging_ctx;
113 notify->list = NULL;
114 notify->array = NULL;
115 notify->iconv_convenience = lp_iconv_convenience(lp_ctx);
116 notify->seqnum = tdb_get_seqnum(notify->w->tdb);
117
118 talloc_set_destructor(notify, notify_destructor);
119
120 /* register with the messaging subsystem for the notify
121 message type */
122 messaging_register(notify->messaging_ctx, notify,
123 MSG_PVFS_NOTIFY, notify_handler);
124
125 notify->sys_notify_ctx = sys_notify_context_create(scfg, notify, ev);
126
127 return notify;
128}
129
130
131/*
132 lock the notify db
133*/
134static NTSTATUS notify_lock(struct notify_context *notify)
135{
136 if (tdb_lock_bystring(notify->w->tdb, NOTIFY_KEY) != 0) {
137 return NT_STATUS_INTERNAL_DB_CORRUPTION;
138 }
139 return NT_STATUS_OK;
140}
141
142/*
143 unlock the notify db
144*/
145static void notify_unlock(struct notify_context *notify)
146{
147 tdb_unlock_bystring(notify->w->tdb, NOTIFY_KEY);
148}
149
150/*
151 load the notify array
152*/
153static NTSTATUS notify_load(struct notify_context *notify)
154{
155 TDB_DATA dbuf;
156 DATA_BLOB blob;
157 enum ndr_err_code ndr_err;
158 int seqnum;
159
160 seqnum = tdb_get_seqnum(notify->w->tdb);
161
162 if (seqnum == notify->seqnum && notify->array != NULL) {
163 return NT_STATUS_OK;
164 }
165
166 notify->seqnum = seqnum;
167
168 talloc_free(notify->array);
169 notify->array = talloc_zero(notify, struct notify_array);
170 NT_STATUS_HAVE_NO_MEMORY(notify->array);
171
172 dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
173 if (dbuf.dptr == NULL) {
174 return NT_STATUS_OK;
175 }
176
177 blob.data = dbuf.dptr;
178 blob.length = dbuf.dsize;
179
180 ndr_err = ndr_pull_struct_blob(&blob, notify->array, notify->iconv_convenience,
181 notify->array,
182 (ndr_pull_flags_fn_t)ndr_pull_notify_array);
183 free(dbuf.dptr);
184 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
185 return ndr_map_error2ntstatus(ndr_err);
186 }
187
188 return NT_STATUS_OK;
189}
190
191/*
192 compare notify entries for sorting
193*/
194static int notify_compare(const void *p1, const void *p2)
195{
196 const struct notify_entry *e1 = p1, *e2 = p2;
197 return strcmp(e1->path, e2->path);
198}
199
200/*
201 save the notify array
202*/
203static NTSTATUS notify_save(struct notify_context *notify)
204{
205 TDB_DATA dbuf;
206 DATA_BLOB blob;
207 enum ndr_err_code ndr_err;
208 int ret;
209 TALLOC_CTX *tmp_ctx;
210
211 /* if possible, remove some depth arrays */
212 while (notify->array->num_depths > 0 &&
213 notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
214 notify->array->num_depths--;
215 }
216
217 /* we might just be able to delete the record */
218 if (notify->array->num_depths == 0) {
219 ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
220 if (ret != 0) {
221 return NT_STATUS_INTERNAL_DB_CORRUPTION;
222 }
223 return NT_STATUS_OK;
224 }
225
226 tmp_ctx = talloc_new(notify);
227 NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
228
229 ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, notify->iconv_convenience, notify->array,
230 (ndr_push_flags_fn_t)ndr_push_notify_array);
231 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
232 talloc_free(tmp_ctx);
233 return ndr_map_error2ntstatus(ndr_err);
234 }
235
236 dbuf.dptr = blob.data;
237 dbuf.dsize = blob.length;
238
239 ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
240 talloc_free(tmp_ctx);
241 if (ret != 0) {
242 return NT_STATUS_INTERNAL_DB_CORRUPTION;
243 }
244
245 return NT_STATUS_OK;
246}
247
248
249/*
250 handle incoming notify messages
251*/
252static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
253 uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
254{
255 struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
256 enum ndr_err_code ndr_err;
257 struct notify_event ev;
258 TALLOC_CTX *tmp_ctx = talloc_new(notify);
259 struct notify_list *listel;
260
261 if (tmp_ctx == NULL) {
262 return;
263 }
264
265 ndr_err = ndr_pull_struct_blob(data, tmp_ctx, notify->iconv_convenience, &ev,
266 (ndr_pull_flags_fn_t)ndr_pull_notify_event);
267 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
268 talloc_free(tmp_ctx);
269 return;
270 }
271
272 for (listel=notify->list;listel;listel=listel->next) {
273 if (listel->private_data == ev.private_data) {
274 listel->callback(listel->private_data, &ev);
275 break;
276 }
277 }
278
279 talloc_free(tmp_ctx);
280}
281
282/*
283 callback from sys_notify telling us about changes from the OS
284*/
285static void sys_notify_callback(struct sys_notify_context *ctx,
286 void *ptr, struct notify_event *ev)
287{
288 struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
289 ev->private_data = listel;
290 listel->callback(listel->private_data, ev);
291}
292
293/*
294 add an entry to the notify array
295*/
296static NTSTATUS notify_add_array(struct notify_context *notify, struct notify_entry *e,
297 void *private_data, int depth)
298{
299 int i;
300 struct notify_depth *d;
301 struct notify_entry *ee;
302
303 /* possibly expand the depths array */
304 if (depth >= notify->array->num_depths) {
305 d = talloc_realloc(notify->array, notify->array->depth,
306 struct notify_depth, depth+1);
307 NT_STATUS_HAVE_NO_MEMORY(d);
308 for (i=notify->array->num_depths;i<=depth;i++) {
309 ZERO_STRUCT(d[i]);
310 }
311 notify->array->depth = d;
312 notify->array->num_depths = depth+1;
313 }
314 d = &notify->array->depth[depth];
315
316 /* expand the entries array */
317 ee = talloc_realloc(notify->array->depth, d->entries, struct notify_entry,
318 d->num_entries+1);
319 NT_STATUS_HAVE_NO_MEMORY(ee);
320 d->entries = ee;
321
322 d->entries[d->num_entries] = *e;
323 d->entries[d->num_entries].private_data = private_data;
324 d->entries[d->num_entries].server = notify->server;
325 d->entries[d->num_entries].path_len = strlen(e->path);
326 d->num_entries++;
327
328 d->max_mask |= e->filter;
329 d->max_mask_subdir |= e->subdir_filter;
330
331 if (d->num_entries > 1) {
332 qsort(d->entries, d->num_entries, sizeof(d->entries[0]), notify_compare);
333 }
334
335 /* recalculate the maximum masks */
336 d->max_mask = 0;
337 d->max_mask_subdir = 0;
338
339 for (i=0;i<d->num_entries;i++) {
340 d->max_mask |= d->entries[i].filter;
341 d->max_mask_subdir |= d->entries[i].subdir_filter;
342 }
343
344 return notify_save(notify);
345}
346
347/*
348 add a notify watch. This is called when a notify is first setup on a open
349 directory handle.
350*/
351NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e0,
352 void (*callback)(void *, const struct notify_event *),
353 void *private_data)
354{
355 struct notify_entry e = *e0;
356 NTSTATUS status;
357 char *tmp_path = NULL;
358 struct notify_list *listel;
359 size_t len;
360 int depth;
361
362 /* see if change notify is enabled at all */
363 if (notify == NULL) {
364 return NT_STATUS_NOT_IMPLEMENTED;
365 }
366
367 status = notify_lock(notify);
368 NT_STATUS_NOT_OK_RETURN(status);
369
370 status = notify_load(notify);
371 if (!NT_STATUS_IS_OK(status)) {
372 goto done;
373 }
374
375 /* cope with /. on the end of the path */
376 len = strlen(e.path);
377 if (len > 1 && e.path[len-1] == '.' && e.path[len-2] == '/') {
378 tmp_path = talloc_strndup(notify, e.path, len-2);
379 if (tmp_path == NULL) {
380 status = NT_STATUS_NO_MEMORY;
381 goto done;
382 }
383 e.path = tmp_path;
384 }
385
386 depth = count_chars(e.path, '/');
387
388 listel = talloc_zero(notify, struct notify_list);
389 if (listel == NULL) {
390 status = NT_STATUS_NO_MEMORY;
391 goto done;
392 }
393
394 listel->private_data = private_data;
395 listel->callback = callback;
396 listel->depth = depth;
397 DLIST_ADD(notify->list, listel);
398
399 /* ignore failures from sys_notify */
400 if (notify->sys_notify_ctx != NULL) {
401 /*
402 this call will modify e.filter and e.subdir_filter
403 to remove bits handled by the backend
404 */
405 status = sys_notify_watch(notify->sys_notify_ctx, &e,
406 sys_notify_callback, listel,
407 &listel->sys_notify_handle);
408 if (NT_STATUS_IS_OK(status)) {
409 talloc_steal(listel, listel->sys_notify_handle);
410 }
411 }
412
413 /* if the system notify handler couldn't handle some of the
414 filter bits, or couldn't handle a request for recursion
415 then we need to install it in the array used for the
416 intra-samba notify handling */
417 if (e.filter != 0 || e.subdir_filter != 0) {
418 status = notify_add_array(notify, &e, private_data, depth);
419 }
420
421done:
422 notify_unlock(notify);
423 talloc_free(tmp_path);
424
425 return status;
426}
427
428/*
429 remove a notify watch. Called when the directory handle is closed
430*/
431NTSTATUS notify_remove(struct notify_context *notify, void *private_data)
432{
433 NTSTATUS status;
434 struct notify_list *listel;
435 int i, depth;
436 struct notify_depth *d;
437
438 /* see if change notify is enabled at all */
439 if (notify == NULL) {
440 return NT_STATUS_NOT_IMPLEMENTED;
441 }
442
443 for (listel=notify->list;listel;listel=listel->next) {
444 if (listel->private_data == private_data) {
445 DLIST_REMOVE(notify->list, listel);
446 break;
447 }
448 }
449 if (listel == NULL) {
450 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
451 }
452
453 depth = listel->depth;
454
455 talloc_free(listel);
456
457 status = notify_lock(notify);
458 NT_STATUS_NOT_OK_RETURN(status);
459
460 status = notify_load(notify);
461 if (!NT_STATUS_IS_OK(status)) {
462 notify_unlock(notify);
463 return status;
464 }
465
466 if (depth >= notify->array->num_depths) {
467 notify_unlock(notify);
468 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
469 }
470
471 /* we only have to search at the depth of this element */
472 d = &notify->array->depth[depth];
473
474 for (i=0;i<d->num_entries;i++) {
475 if (private_data == d->entries[i].private_data &&
476 cluster_id_equal(&notify->server, &d->entries[i].server)) {
477 break;
478 }
479 }
480 if (i == d->num_entries) {
481 notify_unlock(notify);
482 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
483 }
484
485 if (i < d->num_entries-1) {
486 memmove(&d->entries[i], &d->entries[i+1],
487 sizeof(d->entries[i])*(d->num_entries-(i+1)));
488 }
489 d->num_entries--;
490
491 status = notify_save(notify);
492
493 notify_unlock(notify);
494
495 return status;
496}
497
498/*
499 remove all notify watches for this messaging server
500*/
501static NTSTATUS notify_remove_all(struct notify_context *notify)
502{
503 NTSTATUS status;
504 int i, depth, del_count=0;
505
506 if (notify->list == NULL) {
507 return NT_STATUS_OK;
508 }
509
510 status = notify_lock(notify);
511 NT_STATUS_NOT_OK_RETURN(status);
512
513 status = notify_load(notify);
514 if (!NT_STATUS_IS_OK(status)) {
515 notify_unlock(notify);
516 return status;
517 }
518
519 /* we have to search for all entries across all depths, looking for matches
520 for our server id */
521 for (depth=0;depth<notify->array->num_depths;depth++) {
522 struct notify_depth *d = &notify->array->depth[depth];
523 for (i=0;i<d->num_entries;i++) {
524 if (cluster_id_equal(&notify->server, &d->entries[i].server)) {
525 if (i < d->num_entries-1) {
526 memmove(&d->entries[i], &d->entries[i+1],
527 sizeof(d->entries[i])*(d->num_entries-(i+1)));
528 }
529 i--;
530 d->num_entries--;
531 del_count++;
532 }
533 }
534 }
535
536 if (del_count > 0) {
537 status = notify_save(notify);
538 }
539
540 notify_unlock(notify);
541
542 return status;
543}
544
545
546/*
547 send a notify message to another messaging server
548*/
549static void notify_send(struct notify_context *notify, struct notify_entry *e,
550 const char *path, uint32_t action)
551{
552 struct notify_event ev;
553 DATA_BLOB data;
554 NTSTATUS status;
555 enum ndr_err_code ndr_err;
556 TALLOC_CTX *tmp_ctx;
557
558 ev.action = action;
559 ev.path = path;
560 ev.private_data = e->private_data;
561
562 tmp_ctx = talloc_new(notify);
563
564 ndr_err = ndr_push_struct_blob(&data, tmp_ctx, notify->iconv_convenience, &ev, (ndr_push_flags_fn_t)ndr_push_notify_event);
565 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
566 talloc_free(tmp_ctx);
567 return;
568 }
569
570 status = messaging_send(notify->messaging_ctx, e->server,
571 MSG_PVFS_NOTIFY, &data);
572 talloc_free(tmp_ctx);
573}
574
575
576/*
577 trigger a notify message for anyone waiting on a matching event
578
579 This function is called a lot, and needs to be very fast. The unusual data structure
580 and traversal is designed to be fast in the average case, even for large numbers of
581 notifies
582*/
583void notify_trigger(struct notify_context *notify,
584 uint32_t action, uint32_t filter, const char *path)
585{
586 NTSTATUS status;
587 int depth;
588 const char *p, *next_p;
589
590 /* see if change notify is enabled at all */
591 if (notify == NULL) {
592 return;
593 }
594
595 status = notify_load(notify);
596 if (!NT_STATUS_IS_OK(status)) {
597 return;
598 }
599
600 /* loop along the given path, working with each directory depth separately */
601 for (depth=0,p=path;
602 p && depth < notify->array->num_depths;
603 p=next_p,depth++) {
604 int p_len = p - path;
605 int min_i, max_i, i;
606 struct notify_depth *d = &notify->array->depth[depth];
607 next_p = strchr(p+1, '/');
608
609 /* see if there are any entries at this depth */
610 if (d->num_entries == 0) continue;
611
612 /* try to skip based on the maximum mask. If next_p is
613 NULL then we know it will be a 'this directory'
614 match, otherwise it must be a subdir match */
615 if (next_p != NULL) {
616 if (0 == (filter & d->max_mask_subdir)) {
617 continue;
618 }
619 } else {
620 if (0 == (filter & d->max_mask)) {
621 continue;
622 }
623 }
624
625 /* we know there is an entry here worth looking
626 for. Use a bisection search to find the first entry
627 with a matching path */
628 min_i = 0;
629 max_i = d->num_entries-1;
630
631 while (min_i < max_i) {
632 struct notify_entry *e;
633 int cmp;
634 i = (min_i+max_i)/2;
635 e = &d->entries[i];
636 cmp = strncmp(path, e->path, p_len);
637 if (cmp == 0) {
638 if (p_len == e->path_len) {
639 max_i = i;
640 } else {
641 max_i = i-1;
642 }
643 } else if (cmp < 0) {
644 max_i = i-1;
645 } else {
646 min_i = i+1;
647 }
648 }
649
650 if (min_i != max_i) {
651 /* none match */
652 continue;
653 }
654
655 /* we now know that the entries start at min_i */
656 for (i=min_i;i<d->num_entries;i++) {
657 struct notify_entry *e = &d->entries[i];
658 if (p_len != e->path_len ||
659 strncmp(path, e->path, p_len) != 0) break;
660 if (next_p != NULL) {
661 if (0 == (filter & e->subdir_filter)) {
662 continue;
663 }
664 } else {
665 if (0 == (filter & e->filter)) {
666 continue;
667 }
668 }
669 notify_send(notify, e, path + e->path_len + 1, action);
670 }
671 }
672}
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