source: vendor/current/source3/smbd/notify.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 16.8 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 change notify handling
4 Copyright (C) Andrew Tridgell 2000
5 Copyright (C) Jeremy Allison 1994-1998
6 Copyright (C) Volker Lendecke 2007
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20*/
21
22#include "includes.h"
23#include "smbd/smbd.h"
24#include "smbd/globals.h"
25#include "../librpc/gen_ndr/ndr_notify.h"
26#include "librpc/gen_ndr/ndr_file_id.h"
27
28struct notify_change_event {
29 struct timespec when;
30 uint32_t action;
31 const char *name;
32};
33
34struct notify_change_buf {
35 /*
36 * If no requests are pending, changes are queued here. Simple array,
37 * we only append.
38 */
39
40 /*
41 * num_changes == -1 means that we have got a catch-all change, when
42 * asked we just return NT_STATUS_OK without specific changes.
43 */
44 int num_changes;
45 struct notify_change_event *changes;
46
47 /*
48 * If no changes are around requests are queued here. Using a linked
49 * list, because we have to append at the end and delete from the top.
50 */
51 struct notify_change_request *requests;
52};
53
54struct notify_change_request {
55 struct notify_change_request *prev, *next;
56 struct files_struct *fsp; /* backpointer for cancel by mid */
57 struct smb_request *req;
58 uint32_t filter;
59 uint32_t max_param;
60 void (*reply_fn)(struct smb_request *req,
61 NTSTATUS error_code,
62 uint8_t *buf, size_t len);
63 struct notify_mid_map *mid_map;
64 void *backend_data;
65};
66
67static void notify_fsp(files_struct *fsp, struct timespec when,
68 uint32_t action, const char *name);
69
70bool change_notify_fsp_has_changes(struct files_struct *fsp)
71{
72 if (fsp == NULL) {
73 return false;
74 }
75
76 if (fsp->notify == NULL) {
77 return false;
78 }
79
80 if (fsp->notify->num_changes == 0) {
81 return false;
82 }
83
84 return true;
85}
86
87/*
88 * For NTCancel, we need to find the notify_change_request indexed by
89 * mid. Separate list here.
90 */
91
92struct notify_mid_map {
93 struct notify_mid_map *prev, *next;
94 struct notify_change_request *req;
95 uint64_t mid;
96};
97
98static bool notify_change_record_identical(struct notify_change_event *c1,
99 struct notify_change_event *c2)
100{
101 /* Note this is deliberately case sensitive. */
102 if (c1->action == c2->action &&
103 strcmp(c1->name, c2->name) == 0) {
104 return True;
105 }
106 return False;
107}
108
109static int compare_notify_change_events(const void *p1, const void *p2)
110{
111 const struct notify_change_event *e1 = p1;
112 const struct notify_change_event *e2 = p2;
113
114 return timespec_compare(&e1->when, &e2->when);
115}
116
117static bool notify_marshall_changes(int num_changes,
118 uint32_t max_offset,
119 struct notify_change_event *changes,
120 DATA_BLOB *final_blob)
121{
122 int i;
123
124 if (num_changes == -1) {
125 return false;
126 }
127
128 /*
129 * Sort the notifies by timestamp when the event happened to avoid
130 * coalescing and thus dropping events.
131 */
132
133 qsort(changes, num_changes,
134 sizeof(*changes), compare_notify_change_events);
135
136 for (i=0; i<num_changes; i++) {
137 enum ndr_err_code ndr_err;
138 struct notify_change_event *c;
139 struct FILE_NOTIFY_INFORMATION m;
140 DATA_BLOB blob;
141 uint16_t pad = 0;
142
143 /* Coalesce any identical records. */
144 while (i+1 < num_changes &&
145 notify_change_record_identical(&changes[i],
146 &changes[i+1])) {
147 i++;
148 }
149
150 c = &changes[i];
151
152 m.FileName1 = c->name;
153 m.FileNameLength = strlen_m(c->name)*2;
154 m.Action = c->action;
155
156 m._pad = data_blob_null;
157
158 /*
159 * Offset to next entry, only if there is one
160 */
161
162 if (i == (num_changes-1)) {
163 m.NextEntryOffset = 0;
164 } else {
165 if ((m.FileNameLength % 4) == 2) {
166 m._pad = data_blob_const(&pad, 2);
167 }
168 m.NextEntryOffset =
169 ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
170 }
171
172 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
173 (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
174 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
175 return false;
176 }
177
178 if (DEBUGLEVEL >= 10) {
179 NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
180 }
181
182 if (!data_blob_append(talloc_tos(), final_blob,
183 blob.data, blob.length)) {
184 data_blob_free(&blob);
185 return false;
186 }
187
188 data_blob_free(&blob);
189
190 if (final_blob->length > max_offset) {
191 /* Too much data for client. */
192 DEBUG(10, ("Client only wanted %d bytes, trying to "
193 "marshall %d bytes\n", (int)max_offset,
194 (int)final_blob->length));
195 return False;
196 }
197 }
198
199 return True;
200}
201
202/****************************************************************************
203 Setup the common parts of the return packet and send it.
204*****************************************************************************/
205
206void change_notify_reply(struct smb_request *req,
207 NTSTATUS error_code,
208 uint32_t max_param,
209 struct notify_change_buf *notify_buf,
210 void (*reply_fn)(struct smb_request *req,
211 NTSTATUS error_code,
212 uint8_t *buf, size_t len))
213{
214 DATA_BLOB blob = data_blob_null;
215
216 if (!NT_STATUS_IS_OK(error_code)) {
217 reply_fn(req, error_code, NULL, 0);
218 return;
219 }
220
221 if (max_param == 0 || notify_buf == NULL) {
222 reply_fn(req, NT_STATUS_OK, NULL, 0);
223 return;
224 }
225
226 if (!notify_marshall_changes(notify_buf->num_changes, max_param,
227 notify_buf->changes, &blob)) {
228 /*
229 * We exceed what the client is willing to accept. Send
230 * nothing.
231 */
232 data_blob_free(&blob);
233 }
234
235 reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
236
237 data_blob_free(&blob);
238
239 TALLOC_FREE(notify_buf->changes);
240 notify_buf->num_changes = 0;
241}
242
243static void notify_callback(void *private_data, struct timespec when,
244 const struct notify_event *e)
245{
246 files_struct *fsp = (files_struct *)private_data;
247 DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
248 notify_fsp(fsp, when, e->action, e->path);
249}
250
251NTSTATUS change_notify_create(struct files_struct *fsp, uint32_t filter,
252 bool recursive)
253{
254 char *fullpath;
255 size_t len;
256 uint32_t subdir_filter;
257 NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
258
259 if (fsp->notify != NULL) {
260 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
261 "fname = %s\n", fsp->fsp_name->base_name));
262 return NT_STATUS_INVALID_PARAMETER;
263 }
264
265 if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
266 DEBUG(0, ("talloc failed\n"));
267 return NT_STATUS_NO_MEMORY;
268 }
269
270 /* Do notify operations on the base_name. */
271 fullpath = talloc_asprintf(
272 talloc_tos(), "%s/%s", fsp->conn->connectpath,
273 fsp->fsp_name->base_name);
274 if (fullpath == NULL) {
275 DEBUG(0, ("talloc_asprintf failed\n"));
276 TALLOC_FREE(fsp->notify);
277 return NT_STATUS_NO_MEMORY;
278 }
279
280 /*
281 * Avoid /. at the end of the path name. notify can't deal with it.
282 */
283 len = strlen(fullpath);
284 if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
285 fullpath[len-2] = '\0';
286 }
287
288 subdir_filter = recursive ? filter : 0;
289
290 if ((filter != 0) || (subdir_filter != 0)) {
291 status = notify_add(fsp->conn->sconn->notify_ctx,
292 fullpath, filter, subdir_filter,
293 notify_callback, fsp);
294 }
295 TALLOC_FREE(fullpath);
296 return status;
297}
298
299NTSTATUS change_notify_add_request(struct smb_request *req,
300 uint32_t max_param,
301 uint32_t filter, bool recursive,
302 struct files_struct *fsp,
303 void (*reply_fn)(struct smb_request *req,
304 NTSTATUS error_code,
305 uint8_t *buf, size_t len))
306{
307 struct notify_change_request *request = NULL;
308 struct notify_mid_map *map = NULL;
309 struct smbd_server_connection *sconn = req->sconn;
310
311 DEBUG(10, ("change_notify_add_request: Adding request for %s: "
312 "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
313
314 if (!(request = talloc(NULL, struct notify_change_request))
315 || !(map = talloc(request, struct notify_mid_map))) {
316 TALLOC_FREE(request);
317 return NT_STATUS_NO_MEMORY;
318 }
319
320 request->mid_map = map;
321 map->req = request;
322
323 request->req = talloc_move(request, &req);
324 request->max_param = max_param;
325 request->filter = filter;
326 request->fsp = fsp;
327 request->reply_fn = reply_fn;
328 request->backend_data = NULL;
329
330 DLIST_ADD_END(fsp->notify->requests, request);
331
332 map->mid = request->req->mid;
333 DLIST_ADD(sconn->smb1.notify_mid_maps, map);
334
335 return NT_STATUS_OK;
336}
337
338static void change_notify_remove_request(struct smbd_server_connection *sconn,
339 struct notify_change_request *remove_req)
340{
341 files_struct *fsp;
342 struct notify_change_request *req;
343
344 /*
345 * Paranoia checks, the fsp referenced must must have the request in
346 * its list of pending requests
347 */
348
349 fsp = remove_req->fsp;
350 SMB_ASSERT(fsp->notify != NULL);
351
352 for (req = fsp->notify->requests; req; req = req->next) {
353 if (req == remove_req) {
354 break;
355 }
356 }
357
358 if (req == NULL) {
359 smb_panic("notify_req not found in fsp's requests");
360 }
361
362 DLIST_REMOVE(fsp->notify->requests, req);
363 DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
364 TALLOC_FREE(req);
365}
366
367static void smbd_notify_cancel_by_map(struct notify_mid_map *map)
368{
369 struct smb_request *smbreq = map->req->req;
370 struct smbd_server_connection *sconn = smbreq->sconn;
371 struct smbd_smb2_request *smb2req = smbreq->smb2req;
372 NTSTATUS notify_status = NT_STATUS_CANCELLED;
373
374 if (smb2req != NULL) {
375 if (smb2req->session == NULL) {
376 notify_status = STATUS_NOTIFY_CLEANUP;
377 } else if (!NT_STATUS_IS_OK(smb2req->session->status)) {
378 notify_status = STATUS_NOTIFY_CLEANUP;
379 }
380 if (smb2req->tcon == NULL) {
381 notify_status = STATUS_NOTIFY_CLEANUP;
382 } else if (!NT_STATUS_IS_OK(smb2req->tcon->status)) {
383 notify_status = STATUS_NOTIFY_CLEANUP;
384 }
385 }
386
387 change_notify_reply(smbreq, notify_status,
388 0, NULL, map->req->reply_fn);
389 change_notify_remove_request(sconn, map->req);
390}
391
392/****************************************************************************
393 Delete entries by mid from the change notify pending queue. Always send reply.
394*****************************************************************************/
395
396void remove_pending_change_notify_requests_by_mid(
397 struct smbd_server_connection *sconn, uint64_t mid)
398{
399 struct notify_mid_map *map;
400
401 for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
402 if (map->mid == mid) {
403 break;
404 }
405 }
406
407 if (map == NULL) {
408 return;
409 }
410
411 smbd_notify_cancel_by_map(map);
412}
413
414void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
415{
416 struct smbd_server_connection *sconn = smbreq->sconn;
417 struct notify_mid_map *map;
418
419 for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
420 if (map->req->req == smbreq) {
421 break;
422 }
423 }
424
425 if (map == NULL) {
426 return;
427 }
428
429 smbd_notify_cancel_by_map(map);
430}
431
432static struct files_struct *smbd_notify_cancel_deleted_fn(
433 struct files_struct *fsp, void *private_data)
434{
435 struct file_id *fid = talloc_get_type_abort(
436 private_data, struct file_id);
437
438 if (file_id_equal(&fsp->file_id, fid)) {
439 remove_pending_change_notify_requests_by_fid(
440 fsp, NT_STATUS_DELETE_PENDING);
441 }
442 return NULL;
443}
444
445void smbd_notify_cancel_deleted(struct messaging_context *msg,
446 void *private_data, uint32_t msg_type,
447 struct server_id server_id, DATA_BLOB *data)
448{
449 struct smbd_server_connection *sconn = talloc_get_type_abort(
450 private_data, struct smbd_server_connection);
451 struct file_id *fid;
452 enum ndr_err_code ndr_err;
453
454 fid = talloc(talloc_tos(), struct file_id);
455 if (fid == NULL) {
456 DEBUG(1, ("talloc failed\n"));
457 return;
458 }
459
460 ndr_err = ndr_pull_struct_blob_all(
461 data, fid, fid, (ndr_pull_flags_fn_t)ndr_pull_file_id);
462 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
463 DEBUG(10, ("%s: ndr_pull_file_id failed: %s\n", __func__,
464 ndr_errstr(ndr_err)));
465 goto done;
466 }
467
468 files_forall(sconn, smbd_notify_cancel_deleted_fn, fid);
469
470done:
471 TALLOC_FREE(fid);
472}
473
474/****************************************************************************
475 Delete entries by fnum from the change notify pending queue.
476*****************************************************************************/
477
478void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
479 NTSTATUS status)
480{
481 if (fsp->notify == NULL) {
482 return;
483 }
484
485 while (fsp->notify->requests != NULL) {
486 change_notify_reply(fsp->notify->requests->req,
487 status, 0, NULL,
488 fsp->notify->requests->reply_fn);
489 change_notify_remove_request(fsp->conn->sconn,
490 fsp->notify->requests);
491 }
492}
493
494void notify_fname(connection_struct *conn, uint32_t action, uint32_t filter,
495 const char *path)
496{
497 struct notify_context *notify_ctx = conn->sconn->notify_ctx;
498
499 if (path[0] == '.' && path[1] == '/') {
500 path += 2;
501 }
502
503 notify_trigger(notify_ctx, action, filter, conn->connectpath, path);
504}
505
506static void notify_fsp(files_struct *fsp, struct timespec when,
507 uint32_t action, const char *name)
508{
509 struct notify_change_event *change, *changes;
510 char *tmp;
511
512 if (fsp->notify == NULL) {
513 /*
514 * Nobody is waiting, don't queue
515 */
516 return;
517 }
518
519 /*
520 * Someone has triggered a notify previously, queue the change for
521 * later.
522 */
523
524 if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
525 /*
526 * The real number depends on the client buf, just provide a
527 * guard against a DoS here. If name == NULL the CN backend is
528 * alerting us to a problem. Possibly dropped events. Clear
529 * queued changes and send the catch-all response to the client
530 * if a request is pending.
531 */
532 TALLOC_FREE(fsp->notify->changes);
533 fsp->notify->num_changes = -1;
534 if (fsp->notify->requests != NULL) {
535 change_notify_reply(fsp->notify->requests->req,
536 NT_STATUS_OK,
537 fsp->notify->requests->max_param,
538 fsp->notify,
539 fsp->notify->requests->reply_fn);
540 change_notify_remove_request(fsp->conn->sconn,
541 fsp->notify->requests);
542 }
543 return;
544 }
545
546 /* If we've exceeded the server side queue or received a NULL name
547 * from the underlying CN implementation, don't queue up any more
548 * requests until we can send a catch-all response to the client */
549 if (fsp->notify->num_changes == -1) {
550 return;
551 }
552
553 if (!(changes = talloc_realloc(
554 fsp->notify, fsp->notify->changes,
555 struct notify_change_event,
556 fsp->notify->num_changes+1))) {
557 DEBUG(0, ("talloc_realloc failed\n"));
558 return;
559 }
560
561 fsp->notify->changes = changes;
562
563 change = &(fsp->notify->changes[fsp->notify->num_changes]);
564
565 if (!(tmp = talloc_strdup(changes, name))) {
566 DEBUG(0, ("talloc_strdup failed\n"));
567 return;
568 }
569
570 string_replace(tmp, '/', '\\');
571 change->name = tmp;
572
573 change->when = when;
574 change->action = action;
575 fsp->notify->num_changes += 1;
576
577 if (fsp->notify->requests == NULL) {
578 /*
579 * Nobody is waiting, so don't send anything. The ot
580 */
581 return;
582 }
583
584 if (action == NOTIFY_ACTION_OLD_NAME) {
585 /*
586 * We have to send the two rename events in one reply. So hold
587 * the first part back.
588 */
589 return;
590 }
591
592 /*
593 * Someone is waiting for the change, trigger the reply immediately.
594 *
595 * TODO: do we have to walk the lists of requests pending?
596 */
597
598 change_notify_reply(fsp->notify->requests->req,
599 NT_STATUS_OK,
600 fsp->notify->requests->max_param,
601 fsp->notify,
602 fsp->notify->requests->reply_fn);
603
604 change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
605}
606
607char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32_t filter)
608{
609 char *result = NULL;
610
611 result = talloc_strdup(mem_ctx, "");
612
613 if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
614 result = talloc_asprintf_append(result, "FILE_NAME|");
615 if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
616 result = talloc_asprintf_append(result, "DIR_NAME|");
617 if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
618 result = talloc_asprintf_append(result, "ATTRIBUTES|");
619 if (filter & FILE_NOTIFY_CHANGE_SIZE)
620 result = talloc_asprintf_append(result, "SIZE|");
621 if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
622 result = talloc_asprintf_append(result, "LAST_WRITE|");
623 if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
624 result = talloc_asprintf_append(result, "LAST_ACCESS|");
625 if (filter & FILE_NOTIFY_CHANGE_CREATION)
626 result = talloc_asprintf_append(result, "CREATION|");
627 if (filter & FILE_NOTIFY_CHANGE_EA)
628 result = talloc_asprintf_append(result, "EA|");
629 if (filter & FILE_NOTIFY_CHANGE_SECURITY)
630 result = talloc_asprintf_append(result, "SECURITY|");
631 if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
632 result = talloc_asprintf_append(result, "STREAM_NAME|");
633 if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
634 result = talloc_asprintf_append(result, "STREAM_SIZE|");
635 if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
636 result = talloc_asprintf_append(result, "STREAM_WRITE|");
637
638 if (result == NULL) return NULL;
639 if (*result == '\0') return result;
640
641 result[strlen(result)-1] = '\0';
642 return result;
643}
644
645struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
646 struct tevent_context *ev)
647{
648 struct sys_notify_context *ctx;
649
650 if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
651 DEBUG(0, ("talloc failed\n"));
652 return NULL;
653 }
654
655 ctx->ev = ev;
656 ctx->private_data = NULL;
657 return ctx;
658}
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