source: branches/samba-3.2.x/source/smbd/notify_internal.c@ 536

Last change on this file since 536 was 133, checked in by Paul Smedley, 18 years ago

Update trunk to 3.2.0pre3
File size: 16.7 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 "librpc/gen_ndr/ndr_notify.h"
28
29struct notify_context {
30 struct db_context *db;
31 struct server_id server;
32 struct messaging_context *messaging_ctx;
33 struct notify_list *list;
34 struct notify_array *array;
35 int seqnum;
36 struct sys_notify_context *sys_notify_ctx;
37 TDB_DATA key;
38};
39
40
41struct notify_list {
42 struct notify_list *next, *prev;
43 void *private_data;
44 void (*callback)(void *, const struct notify_event *);
45 void *sys_notify_handle;
46 int depth;
47};
48
49#define NOTIFY_KEY "notify array"
50
51#define NOTIFY_ENABLE "notify:enable"
52#define NOTIFY_ENABLE_DEFAULT True
53
54static NTSTATUS notify_remove_all(struct notify_context *notify,
55 const struct server_id *server);
56static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
57 uint32_t msg_type, struct server_id server_id, DATA_BLOB *data);
58
59/*
60 destroy the notify context
61*/
62static int notify_destructor(struct notify_context *notify)
63{
64 messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
65
66 if (notify->list != NULL) {
67 notify_remove_all(notify, &notify->server);
68 }
69
70 return 0;
71}
72
73/*
74 Open up the notify.tdb database. You should close it down using
75 talloc_free(). We need the messaging_ctx to allow for notifications
76 via internal messages
77*/
78struct notify_context *notify_init(TALLOC_CTX *mem_ctx, struct server_id server,
79 struct messaging_context *messaging_ctx,
80 struct event_context *ev,
81 connection_struct *conn)
82{
83 struct notify_context *notify;
84
85 if (!lp_change_notify(conn->params)) {
86 return NULL;
87 }
88
89 notify = talloc(mem_ctx, struct notify_context);
90 if (notify == NULL) {
91 return NULL;
92 }
93
94 notify->db = db_open(notify, lock_path("notify.tdb"),
95 0, TDB_SEQNUM|TDB_CLEAR_IF_FIRST,
96 O_RDWR|O_CREAT, 0644);
97 if (notify->db == NULL) {
98 talloc_free(notify);
99 return NULL;
100 }
101
102 notify->server = server;
103 notify->messaging_ctx = messaging_ctx;
104 notify->list = NULL;
105 notify->array = NULL;
106 notify->seqnum = notify->db->get_seqnum(notify->db);
107 notify->key = string_term_tdb_data(NOTIFY_KEY);
108
109 talloc_set_destructor(notify, notify_destructor);
110
111 /* register with the messaging subsystem for the notify
112 message type */
113 messaging_register(notify->messaging_ctx, notify,
114 MSG_PVFS_NOTIFY, notify_handler);
115
116 notify->sys_notify_ctx = sys_notify_context_create(conn, notify, ev);
117
118 return notify;
119}
120
121/*
122 lock and fetch the record
123*/
124static NTSTATUS notify_fetch_locked(struct notify_context *notify, struct db_record **rec)
125{
126 *rec = notify->db->fetch_locked(notify->db, notify, notify->key);
127 if (*rec == NULL) {
128 return NT_STATUS_INTERNAL_DB_CORRUPTION;
129 }
130 return NT_STATUS_OK;
131}
132
133/*
134 load the notify array
135*/
136static NTSTATUS notify_load(struct notify_context *notify, struct db_record *rec)
137{
138 TDB_DATA dbuf;
139 DATA_BLOB blob;
140 NTSTATUS status;
141 int seqnum;
142
143 seqnum = notify->db->get_seqnum(notify->db);
144
145 if (seqnum == notify->seqnum && notify->array != NULL) {
146 return NT_STATUS_OK;
147 }
148
149 notify->seqnum = seqnum;
150
151 talloc_free(notify->array);
152 notify->array = TALLOC_ZERO_P(notify, struct notify_array);
153 NT_STATUS_HAVE_NO_MEMORY(notify->array);
154
155 if (!rec) {
156 if (notify->db->fetch(notify->db, notify, notify->key, &dbuf) != 0) {
157 return NT_STATUS_INTERNAL_DB_CORRUPTION;
158 }
159 } else {
160 dbuf = rec->value;
161 }
162
163 blob.data = (uint8 *)dbuf.dptr;
164 blob.length = dbuf.dsize;
165
166 status = NT_STATUS_OK;
167 if (blob.length > 0) {
168 enum ndr_err_code ndr_err;
169 ndr_err = ndr_pull_struct_blob(&blob, notify->array, notify->array,
170 (ndr_pull_flags_fn_t)ndr_pull_notify_array);
171 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
172 status = ndr_map_error2ntstatus(ndr_err);
173 }
174 }
175
176 if (DEBUGLEVEL >= 10) {
177 DEBUG(10, ("notify_load:\n"));
178 NDR_PRINT_DEBUG(notify_array, notify->array);
179 }
180
181 if (!rec) {
182 talloc_free(dbuf.dptr);
183 }
184
185 return status;
186}
187
188/*
189 compare notify entries for sorting
190*/
191static int notify_compare(const void *p1, const void *p2)
192{
193 const struct notify_entry *e1 = (const struct notify_entry *)p1;
194 const struct notify_entry *e2 = (const struct notify_entry *)p2;
195 return strcmp(e1->path, e2->path);
196}
197
198/*
199 save the notify array
200*/
201static NTSTATUS notify_save(struct notify_context *notify, struct db_record *rec)
202{
203 TDB_DATA dbuf;
204 DATA_BLOB blob;
205 NTSTATUS status;
206 enum ndr_err_code ndr_err;
207 TALLOC_CTX *tmp_ctx;
208
209 /* if possible, remove some depth arrays */
210 while (notify->array->num_depths > 0 &&
211 notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
212 notify->array->num_depths--;
213 }
214
215 /* we might just be able to delete the record */
216 if (notify->array->num_depths == 0) {
217 return rec->delete_rec(rec);
218 }
219
220 tmp_ctx = talloc_new(notify);
221 NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
222
223 ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, notify->array,
224 (ndr_push_flags_fn_t)ndr_push_notify_array);
225 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
226 talloc_free(tmp_ctx);
227 return ndr_map_error2ntstatus(ndr_err);
228 }
229
230 if (DEBUGLEVEL >= 10) {
231 DEBUG(10, ("notify_save:\n"));
232 NDR_PRINT_DEBUG(notify_array, notify->array);
233 }
234
235 dbuf.dptr = blob.data;
236 dbuf.dsize = blob.length;
237
238 status = rec->store(rec, dbuf, TDB_REPLACE);
239 talloc_free(tmp_ctx);
240
241 return status;
242}
243
244
245/*
246 handle incoming notify messages
247*/
248static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
249 uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
250{
251 struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
252 enum ndr_err_code ndr_err;
253 struct notify_event ev;
254 TALLOC_CTX *tmp_ctx = talloc_new(notify);
255 struct notify_list *listel;
256
257 if (tmp_ctx == NULL) {
258 return;
259 }
260
261 ndr_err = ndr_pull_struct_blob(data, tmp_ctx, &ev,
262 (ndr_pull_flags_fn_t)ndr_pull_notify_event);
263 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
264 talloc_free(tmp_ctx);
265 return;
266 }
267
268 for (listel=notify->list;listel;listel=listel->next) {
269 if (listel->private_data == ev.private_data) {
270 listel->callback(listel->private_data, &ev);
271 break;
272 }
273 }
274
275 talloc_free(tmp_ctx);
276}
277
278/*
279 callback from sys_notify telling us about changes from the OS
280*/
281static void sys_notify_callback(struct sys_notify_context *ctx,
282 void *ptr, struct notify_event *ev)
283{
284 struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
285 ev->private_data = listel;
286 DEBUG(10, ("sys_notify_callback called with action=%d, for %s\n",
287 ev->action, ev->path));
288 listel->callback(listel->private_data, ev);
289}
290
291/*
292 add an entry to the notify array
293*/
294static NTSTATUS notify_add_array(struct notify_context *notify, struct db_record *rec,
295 struct notify_entry *e,
296 void *private_data, int depth)
297{
298 int i;
299 struct notify_depth *d;
300 struct notify_entry *ee;
301
302 /* possibly expand the depths array */
303 if (depth >= notify->array->num_depths) {
304 d = talloc_realloc(notify->array, notify->array->depth,
305 struct notify_depth, depth+1);
306 NT_STATUS_HAVE_NO_MEMORY(d);
307 for (i=notify->array->num_depths;i<=depth;i++) {
308 ZERO_STRUCT(d[i]);
309 }
310 notify->array->depth = d;
311 notify->array->num_depths = depth+1;
312 }
313 d = &notify->array->depth[depth];
314
315 /* expand the entries array */
316 ee = talloc_realloc(notify->array->depth, d->entries, struct notify_entry,
317 d->num_entries+1);
318 NT_STATUS_HAVE_NO_MEMORY(ee);
319 d->entries = ee;
320
321 d->entries[d->num_entries] = *e;
322 d->entries[d->num_entries].private_data = private_data;
323 d->entries[d->num_entries].server = notify->server;
324 d->entries[d->num_entries].path_len = strlen(e->path);
325 d->num_entries++;
326
327 d->max_mask |= e->filter;
328 d->max_mask_subdir |= e->subdir_filter;
329
330 if (d->num_entries > 1) {
331 qsort(d->entries, d->num_entries, sizeof(d->entries[0]), notify_compare);
332 }
333
334 /* recalculate the maximum masks */
335 d->max_mask = 0;
336 d->max_mask_subdir = 0;
337
338 for (i=0;i<d->num_entries;i++) {
339 d->max_mask |= d->entries[i].filter;
340 d->max_mask_subdir |= d->entries[i].subdir_filter;
341 }
342
343 return notify_save(notify, rec);
344}
345
346/*
347 add a notify watch. This is called when a notify is first setup on a open
348 directory handle.
349*/
350NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e0,
351 void (*callback)(void *, const struct notify_event *),
352 void *private_data)
353{
354 struct notify_entry e = *e0;
355 NTSTATUS status;
356 char *tmp_path = NULL;
357 struct notify_list *listel;
358 size_t len;
359 int depth;
360 struct db_record *rec;
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_fetch_locked(notify, &rec);
368 NT_STATUS_NOT_OK_RETURN(status);
369
370 status = notify_load(notify, rec);
371 if (!NT_STATUS_IS_OK(status)) {
372 talloc_free(rec);
373 return status;
374 }
375
376 /* cope with /. on the end of the path */
377 len = strlen(e.path);
378 if (len > 1 && e.path[len-1] == '.' && e.path[len-2] == '/') {
379 tmp_path = talloc_strndup(notify, e.path, len-2);
380 if (tmp_path == NULL) {
381 status = NT_STATUS_NO_MEMORY;
382 goto done;
383 }
384 e.path = tmp_path;
385 }
386
387 depth = count_chars(e.path, '/');
388
389 listel = TALLOC_ZERO_P(notify, struct notify_list);
390 if (listel == NULL) {
391 status = NT_STATUS_NO_MEMORY;
392 goto done;
393 }
394
395 listel->private_data = private_data;
396 listel->callback = callback;
397 listel->depth = depth;
398 DLIST_ADD(notify->list, listel);
399
400 /* ignore failures from sys_notify */
401 if (notify->sys_notify_ctx != NULL) {
402 /*
403 this call will modify e.filter and e.subdir_filter
404 to remove bits handled by the backend
405 */
406 status = sys_notify_watch(notify->sys_notify_ctx, &e,
407 sys_notify_callback, listel,
408 &listel->sys_notify_handle);
409 if (NT_STATUS_IS_OK(status)) {
410 talloc_steal(listel, listel->sys_notify_handle);
411 }
412 }
413
414 /* if the system notify handler couldn't handle some of the
415 filter bits, or couldn't handle a request for recursion
416 then we need to install it in the array used for the
417 intra-samba notify handling */
418 if (e.filter != 0 || e.subdir_filter != 0) {
419 status = notify_add_array(notify, rec, &e, private_data, depth);
420 }
421
422done:
423 talloc_free(rec);
424 talloc_free(tmp_path);
425
426 return status;
427}
428
429/*
430 remove a notify watch. Called when the directory handle is closed
431*/
432NTSTATUS notify_remove(struct notify_context *notify, void *private_data)
433{
434 NTSTATUS status;
435 struct notify_list *listel;
436 int i, depth;
437 struct notify_depth *d;
438 struct db_record *rec;
439
440 /* see if change notify is enabled at all */
441 if (notify == NULL) {
442 return NT_STATUS_NOT_IMPLEMENTED;
443 }
444
445 for (listel=notify->list;listel;listel=listel->next) {
446 if (listel->private_data == private_data) {
447 DLIST_REMOVE(notify->list, listel);
448 break;
449 }
450 }
451 if (listel == NULL) {
452 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
453 }
454
455 depth = listel->depth;
456
457 talloc_free(listel);
458
459 status = notify_fetch_locked(notify, &rec);
460 NT_STATUS_NOT_OK_RETURN(status);
461
462 status = notify_load(notify, rec);
463 if (!NT_STATUS_IS_OK(status)) {
464 talloc_free(rec);
465 return status;
466 }
467
468 if (depth >= notify->array->num_depths) {
469 talloc_free(rec);
470 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
471 }
472
473 /* we only have to search at the depth of this element */
474 d = &notify->array->depth[depth];
475
476 for (i=0;i<d->num_entries;i++) {
477 if (private_data == d->entries[i].private_data &&
478 cluster_id_equal(&notify->server, &d->entries[i].server)) {
479 break;
480 }
481 }
482 if (i == d->num_entries) {
483 talloc_free(rec);
484 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
485 }
486
487 if (i < d->num_entries-1) {
488 memmove(&d->entries[i], &d->entries[i+1],
489 sizeof(d->entries[i])*(d->num_entries-(i+1)));
490 }
491 d->num_entries--;
492
493 status = notify_save(notify, rec);
494
495 talloc_free(rec);
496
497 return status;
498}
499
500/*
501 remove all notify watches for a messaging server
502*/
503static NTSTATUS notify_remove_all(struct notify_context *notify,
504 const struct server_id *server)
505{
506 NTSTATUS status;
507 int i, depth, del_count=0;
508 struct db_record *rec;
509
510 status = notify_fetch_locked(notify, &rec);
511 NT_STATUS_NOT_OK_RETURN(status);
512
513 status = notify_load(notify, rec);
514 if (!NT_STATUS_IS_OK(status)) {
515 talloc_free(rec);
516 return status;
517 }
518
519 /* we have to search for all entries across all depths, looking for matches
520 for the 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(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, rec);
538 }
539
540 talloc_free(rec);
541
542 return status;
543}
544
545
546/*
547 send a notify message to another messaging server
548*/
549static NTSTATUS 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, &ev,
565 (ndr_push_flags_fn_t)ndr_push_notify_event);
566 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
567 talloc_free(tmp_ctx);
568 return ndr_map_error2ntstatus(ndr_err);
569 }
570
571 status = messaging_send(notify->messaging_ctx, e->server,
572 MSG_PVFS_NOTIFY, &data);
573 talloc_free(tmp_ctx);
574 return status;
575}
576
577
578/*
579 trigger a notify message for anyone waiting on a matching event
580
581 This function is called a lot, and needs to be very fast. The unusual data structure
582 and traversal is designed to be fast in the average case, even for large numbers of
583 notifies
584*/
585void notify_trigger(struct notify_context *notify,
586 uint32_t action, uint32_t filter, const char *path)
587{
588 NTSTATUS status;
589 int depth;
590 const char *p, *next_p;
591
592 DEBUG(10, ("notify_trigger called action=0x%x, filter=0x%x, "
593 "path=%s\n", (unsigned)action, (unsigned)filter, path));
594
595 /* see if change notify is enabled at all */
596 if (notify == NULL) {
597 return;
598 }
599
600 again:
601 status = notify_load(notify, NULL);
602 if (!NT_STATUS_IS_OK(status)) {
603 return;
604 }
605
606 /* loop along the given path, working with each directory depth separately */
607 for (depth=0,p=path;
608 p && depth < notify->array->num_depths;
609 p=next_p,depth++) {
610 int p_len = p - path;
611 int min_i, max_i, i;
612 struct notify_depth *d = &notify->array->depth[depth];
613 next_p = strchr(p+1, '/');
614
615 /* see if there are any entries at this depth */
616 if (d->num_entries == 0) continue;
617
618 /* try to skip based on the maximum mask. If next_p is
619 NULL then we know it will be a 'this directory'
620 match, otherwise it must be a subdir match */
621 if (next_p != NULL) {
622 if (0 == (filter & d->max_mask_subdir)) {
623 continue;
624 }
625 } else {
626 if (0 == (filter & d->max_mask)) {
627 continue;
628 }
629 }
630
631 /* we know there is an entry here worth looking
632 for. Use a bisection search to find the first entry
633 with a matching path */
634 min_i = 0;
635 max_i = d->num_entries-1;
636
637 while (min_i < max_i) {
638 struct notify_entry *e;
639 int cmp;
640 i = (min_i+max_i)/2;
641 e = &d->entries[i];
642 cmp = strncmp(path, e->path, p_len);
643 if (cmp == 0) {
644 if (p_len == e->path_len) {
645 max_i = i;
646 } else {
647 max_i = i-1;
648 }
649 } else if (cmp < 0) {
650 max_i = i-1;
651 } else {
652 min_i = i+1;
653 }
654 }
655
656 if (min_i != max_i) {
657 /* none match */
658 continue;
659 }
660
661 /* we now know that the entries start at min_i */
662 for (i=min_i;i<d->num_entries;i++) {
663 struct notify_entry *e = &d->entries[i];
664 if (p_len != e->path_len ||
665 strncmp(path, e->path, p_len) != 0) break;
666 if (next_p != NULL) {
667 if (0 == (filter & e->subdir_filter)) {
668 continue;
669 }
670 } else {
671 if (0 == (filter & e->filter)) {
672 continue;
673 }
674 }
675 status = notify_send(notify, e, path + e->path_len + 1,
676 action);
677
678 if (NT_STATUS_EQUAL(
679 status, NT_STATUS_INVALID_HANDLE)) {
680 struct server_id server = e->server;
681
682 DEBUG(10, ("Deleting notify entries for "
683 "process %s because it's gone\n",
684 procid_str_static(&e->server)));
685 notify_remove_all(notify, &server);
686 goto again;
687 }
688 }
689 }
690}
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