source: trunk-3.0/source/smbd/notify_internal.c@ 103

Last change on this file since 103 was 39, checked in by Paul Smedley, 18 years ago

Upgrade source to 3.0.25a
File size: 17.0 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 2 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, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19*/
20
21/*
22 this is the change notify database. It implements mechanisms for
23 storing current change notify waiters in a tdb, and checking if a
24 given event matches any of the stored notify waiiters.
25*/
26
27#include "includes.h"
28#include "librpc/gen_ndr/ndr_notify.h"
29
30struct notify_context {
31 struct tdb_wrap *w;
32 struct server_id server;
33 struct messaging_context *messaging_ctx;
34 struct notify_list *list;
35 struct notify_array *array;
36 int seqnum;
37 struct sys_notify_context *sys_notify_ctx;
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->w = tdb_wrap_open(notify, lock_path("notify.tdb"),
95 0, TDB_SEQNUM|TDB_CLEAR_IF_FIRST,
96 O_RDWR|O_CREAT, 0644);
97 if (notify->w == 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 = tdb_get_seqnum(notify->w->tdb);
107
108 talloc_set_destructor(notify, notify_destructor);
109
110 /* register with the messaging subsystem for the notify
111 message type */
112 messaging_register(notify->messaging_ctx, notify,
113 MSG_PVFS_NOTIFY, notify_handler);
114
115 notify->sys_notify_ctx = sys_notify_context_create(conn, notify, ev);
116
117 return notify;
118}
119
120
121/*
122 lock the notify db
123*/
124static NTSTATUS notify_lock(struct notify_context *notify)
125{
126 if (tdb_lock_bystring(notify->w->tdb, NOTIFY_KEY) != 0) {
127 return NT_STATUS_INTERNAL_DB_CORRUPTION;
128 }
129 return NT_STATUS_OK;
130}
131
132/*
133 unlock the notify db
134*/
135static void notify_unlock(struct notify_context *notify)
136{
137 tdb_unlock_bystring(notify->w->tdb, NOTIFY_KEY);
138}
139
140/*
141 load the notify array
142*/
143static NTSTATUS notify_load(struct notify_context *notify)
144{
145 TDB_DATA dbuf;
146 DATA_BLOB blob;
147 NTSTATUS status;
148 int seqnum;
149
150 seqnum = tdb_get_seqnum(notify->w->tdb);
151
152 if (seqnum == notify->seqnum && notify->array != NULL) {
153 return NT_STATUS_OK;
154 }
155
156 notify->seqnum = seqnum;
157
158 talloc_free(notify->array);
159 notify->array = TALLOC_ZERO_P(notify, struct notify_array);
160 NT_STATUS_HAVE_NO_MEMORY(notify->array);
161
162 dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
163 if (dbuf.dptr == NULL) {
164 return NT_STATUS_OK;
165 }
166
167 blob.data = (uint8 *)dbuf.dptr;
168 blob.length = dbuf.dsize;
169
170 status = ndr_pull_struct_blob(&blob, notify->array, notify->array,
171 (ndr_pull_flags_fn_t)ndr_pull_notify_array);
172
173 if (DEBUGLEVEL >= 10) {
174 DEBUG(10, ("notify_load:\n"));
175 NDR_PRINT_DEBUG(notify_array, notify->array);
176 }
177
178 free(dbuf.dptr);
179
180 return status;
181}
182
183/*
184 compare notify entries for sorting
185*/
186static int notify_compare(const void *p1, const void *p2)
187{
188 const struct notify_entry *e1 = (const struct notify_entry *)p1;
189 const struct notify_entry *e2 = (const struct notify_entry *)p2;
190 return strcmp(e1->path, e2->path);
191}
192
193/*
194 save the notify array
195*/
196static NTSTATUS notify_save(struct notify_context *notify)
197{
198 TDB_DATA dbuf;
199 DATA_BLOB blob;
200 NTSTATUS status;
201 int ret;
202 TALLOC_CTX *tmp_ctx;
203
204 /* if possible, remove some depth arrays */
205 while (notify->array->num_depths > 0 &&
206 notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
207 notify->array->num_depths--;
208 }
209
210 /* we might just be able to delete the record */
211 if (notify->array->num_depths == 0) {
212 ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
213 if (ret != 0) {
214 return NT_STATUS_INTERNAL_DB_CORRUPTION;
215 }
216 return NT_STATUS_OK;
217 }
218
219 tmp_ctx = talloc_new(notify);
220 NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
221
222 status = ndr_push_struct_blob(&blob, tmp_ctx, notify->array,
223 (ndr_push_flags_fn_t)ndr_push_notify_array);
224 if (!NT_STATUS_IS_OK(status)) {
225 talloc_free(tmp_ctx);
226 return status;
227 }
228
229 if (DEBUGLEVEL >= 10) {
230 DEBUG(10, ("notify_save:\n"));
231 NDR_PRINT_DEBUG(notify_array, notify->array);
232 }
233
234 dbuf.dptr = (char *)blob.data;
235 dbuf.dsize = blob.length;
236
237 ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
238 talloc_free(tmp_ctx);
239 if (ret != 0) {
240 return NT_STATUS_INTERNAL_DB_CORRUPTION;
241 }
242
243 return NT_STATUS_OK;
244}
245
246
247/*
248 handle incoming notify messages
249*/
250static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
251 uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
252{
253 struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
254 NTSTATUS status;
255 struct notify_event ev;
256 TALLOC_CTX *tmp_ctx = talloc_new(notify);
257 struct notify_list *listel;
258
259 if (tmp_ctx == NULL) {
260 return;
261 }
262
263 status = ndr_pull_struct_blob(data, tmp_ctx, &ev,
264 (ndr_pull_flags_fn_t)ndr_pull_notify_event);
265 if (!NT_STATUS_IS_OK(status)) {
266 talloc_free(tmp_ctx);
267 return;
268 }
269
270 for (listel=notify->list;listel;listel=listel->next) {
271 if (listel->private_data == ev.private_data) {
272 listel->callback(listel->private_data, &ev);
273 break;
274 }
275 }
276
277 talloc_free(tmp_ctx);
278}
279
280/*
281 callback from sys_notify telling us about changes from the OS
282*/
283static void sys_notify_callback(struct sys_notify_context *ctx,
284 void *ptr, struct notify_event *ev)
285{
286 struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
287 ev->private_data = listel;
288 DEBUG(10, ("sys_notify_callback called with action=%d, for %s\n",
289 ev->action, ev->path));
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_P(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 a messaging server
500*/
501static NTSTATUS notify_remove_all(struct notify_context *notify,
502 const struct server_id *server)
503{
504 NTSTATUS status;
505 int i, depth, del_count=0;
506
507 status = notify_lock(notify);
508 NT_STATUS_NOT_OK_RETURN(status);
509
510 status = notify_load(notify);
511 if (!NT_STATUS_IS_OK(status)) {
512 notify_unlock(notify);
513 return status;
514 }
515
516 /* we have to search for all entries across all depths, looking for matches
517 for the server id */
518 for (depth=0;depth<notify->array->num_depths;depth++) {
519 struct notify_depth *d = &notify->array->depth[depth];
520 for (i=0;i<d->num_entries;i++) {
521 if (cluster_id_equal(server, &d->entries[i].server)) {
522 if (i < d->num_entries-1) {
523 memmove(&d->entries[i], &d->entries[i+1],
524 sizeof(d->entries[i])*(d->num_entries-(i+1)));
525 }
526 i--;
527 d->num_entries--;
528 del_count++;
529 }
530 }
531 }
532
533 if (del_count > 0) {
534 status = notify_save(notify);
535 }
536
537 notify_unlock(notify);
538
539 return status;
540}
541
542
543/*
544 send a notify message to another messaging server
545*/
546static NTSTATUS notify_send(struct notify_context *notify, struct notify_entry *e,
547 const char *path, uint32_t action)
548{
549 struct notify_event ev;
550 DATA_BLOB data;
551 NTSTATUS status;
552 TALLOC_CTX *tmp_ctx;
553
554 ev.action = action;
555 ev.path = path;
556 ev.private_data = e->private_data;
557
558 tmp_ctx = talloc_new(notify);
559
560 status = ndr_push_struct_blob(&data, tmp_ctx, &ev,
561 (ndr_push_flags_fn_t)ndr_push_notify_event);
562 if (!NT_STATUS_IS_OK(status)) {
563 talloc_free(tmp_ctx);
564 return status;
565 }
566
567 status = messaging_send(notify->messaging_ctx, e->server,
568 MSG_PVFS_NOTIFY, &data);
569 talloc_free(tmp_ctx);
570 return status;
571}
572
573
574/*
575 trigger a notify message for anyone waiting on a matching event
576
577 This function is called a lot, and needs to be very fast. The unusual data structure
578 and traversal is designed to be fast in the average case, even for large numbers of
579 notifies
580*/
581void notify_trigger(struct notify_context *notify,
582 uint32_t action, uint32_t filter, const char *path)
583{
584 NTSTATUS status;
585 int depth;
586 const char *p, *next_p;
587
588 DEBUG(10, ("notify_trigger called action=0x%x, filter=0x%x, "
589 "path=%s\n", (unsigned)action, (unsigned)filter, path));
590
591 /* see if change notify is enabled at all */
592 if (notify == NULL) {
593 return;
594 }
595
596 again:
597 status = notify_load(notify);
598 if (!NT_STATUS_IS_OK(status)) {
599 return;
600 }
601
602 /* loop along the given path, working with each directory depth separately */
603 for (depth=0,p=path;
604 p && depth < notify->array->num_depths;
605 p=next_p,depth++) {
606 int p_len = p - path;
607 int min_i, max_i, i;
608 struct notify_depth *d = &notify->array->depth[depth];
609 next_p = strchr(p+1, '/');
610
611 /* see if there are any entries at this depth */
612 if (d->num_entries == 0) continue;
613
614 /* try to skip based on the maximum mask. If next_p is
615 NULL then we know it will be a 'this directory'
616 match, otherwise it must be a subdir match */
617 if (next_p != NULL) {
618 if (0 == (filter & d->max_mask_subdir)) {
619 continue;
620 }
621 } else {
622 if (0 == (filter & d->max_mask)) {
623 continue;
624 }
625 }
626
627 /* we know there is an entry here worth looking
628 for. Use a bisection search to find the first entry
629 with a matching path */
630 min_i = 0;
631 max_i = d->num_entries-1;
632
633 while (min_i < max_i) {
634 struct notify_entry *e;
635 int cmp;
636 i = (min_i+max_i)/2;
637 e = &d->entries[i];
638 cmp = strncmp(path, e->path, p_len);
639 if (cmp == 0) {
640 if (p_len == e->path_len) {
641 max_i = i;
642 } else {
643 max_i = i-1;
644 }
645 } else if (cmp < 0) {
646 max_i = i-1;
647 } else {
648 min_i = i+1;
649 }
650 }
651
652 if (min_i != max_i) {
653 /* none match */
654 continue;
655 }
656
657 /* we now know that the entries start at min_i */
658 for (i=min_i;i<d->num_entries;i++) {
659 struct notify_entry *e = &d->entries[i];
660 if (p_len != e->path_len ||
661 strncmp(path, e->path, p_len) != 0) break;
662 if (next_p != NULL) {
663 if (0 == (filter & e->subdir_filter)) {
664 continue;
665 }
666 } else {
667 if (0 == (filter & e->filter)) {
668 continue;
669 }
670 }
671 status = notify_send(notify, e, path + e->path_len + 1,
672 action);
673
674 if (NT_STATUS_EQUAL(
675 status, NT_STATUS_INVALID_HANDLE)) {
676 struct server_id server = e->server;
677
678 DEBUG(10, ("Deleting notify entries for "
679 "process %s because it's gone\n",
680 procid_str_static(&e->server.id)));
681 notify_remove_all(notify, &server);
682 goto again;
683 }
684 }
685 }
686}
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