source3/smbd/notify.c

   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
  28 struct notify_change_event {
  29         struct timespec when;
  30         uint32_t action;
  31         const char *name;
  32 };
  33
  34 struct 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
  54 struct 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
  67 static void notify_fsp(files_struct *fsp, struct timespec when,
  68                        uint32_t action, const char *name);
  69
  70 bool 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
  92 struct notify_mid_map {
  93         struct notify_mid_map *prev, *next;
  94         struct notify_change_request *req;
  95         uint64_t mid;
  96 };
  97
  98 static 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
 109 static 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
 117 static 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
 142                 /* Coalesce any identical records. */
 143                 while (i+1 < num_changes &&
 144                         notify_change_record_identical(&changes[i],
 145                                                 &changes[i+1])) {
 146                         i++;
 147                 }
 148
 149                 c = &changes[i];
 150
 151                 m.FileName1 = c->name;
 152                 m.FileNameLength = strlen_m(c->name)*2;
 153                 m.Action = c->action;
 154                 m.NextEntryOffset = (i == num_changes-1) ? 0 : ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
 155
 156                 /*
 157                  * Offset to next entry, only if there is one
 158                  */
 159
 160                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
 161                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 162                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 163                         return false;
 164                 }
 165
 166                 if (DEBUGLEVEL >= 10) {
 167                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 168                 }
 169
 170                 if (!data_blob_append(talloc_tos(), final_blob,
 171                                       blob.data, blob.length)) {
 172                         data_blob_free(&blob);
 173                         return false;
 174                 }
 175
 176                 data_blob_free(&blob);
 177
 178                 if (final_blob->length > max_offset) {
 179                         /* Too much data for client. */
 180                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 181                                    "marshall %d bytes\n", (int)max_offset,
 182                                    (int)final_blob->length));
 183                         return False;
 184                 }
 185         }
 186
 187         return True;
 188 }
 189
 190 /****************************************************************************
 191  Setup the common parts of the return packet and send it.
 192 *****************************************************************************/
 193
 194 void change_notify_reply(struct smb_request *req,
 195                          NTSTATUS error_code,
 196                          uint32_t max_param,
 197                          struct notify_change_buf *notify_buf,
 198                          void (*reply_fn)(struct smb_request *req,
 199                                           NTSTATUS error_code,
 200                                           uint8_t *buf, size_t len))
 201 {
 202         DATA_BLOB blob = data_blob_null;
 203
 204         if (!NT_STATUS_IS_OK(error_code)) {
 205                 reply_fn(req, error_code, NULL, 0);
 206                 return;
 207         }
 208
 209         if (max_param == 0 || notify_buf == NULL) {
 210                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 211                 return;
 212         }
 213
 214         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 215                                         notify_buf->changes, &blob)) {
 216                 /*
 217                  * We exceed what the client is willing to accept. Send
 218                  * nothing.
 219                  */
 220                 data_blob_free(&blob);
 221         }
 222
 223         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 224
 225         data_blob_free(&blob);
 226
 227         TALLOC_FREE(notify_buf->changes);
 228         notify_buf->num_changes = 0;
 229 }
 230
 231 static void notify_callback(void *private_data, struct timespec when,
 232                             const struct notify_event *e)
 233 {
 234         files_struct *fsp = (files_struct *)private_data;
 235         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 236         notify_fsp(fsp, when, e->action, e->path);
 237 }
 238
 239 static void sys_notify_callback(struct sys_notify_context *ctx,
 240                                 void *private_data,
 241                                 struct notify_event *e)
 242 {
 243         files_struct *fsp = (files_struct *)private_data;
 244         DEBUG(10, ("sys_notify_callback called for %s\n", fsp_str_dbg(fsp)));
 245         notify_fsp(fsp, timespec_current(), e->action, e->path);
 246 }
 247
 248 NTSTATUS change_notify_create(struct files_struct *fsp, uint32_t filter,
 249                               bool recursive)
 250 {
 251         char *fullpath;
 252         size_t len;
 253         uint32_t subdir_filter;
 254         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 255
 256         if (fsp->notify != NULL) {
 257                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 258                           "fname = %s\n", fsp->fsp_name->base_name));
 259                 return NT_STATUS_INVALID_PARAMETER;
 260         }
 261
 262         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 263                 DEBUG(0, ("talloc failed\n"));
 264                 return NT_STATUS_NO_MEMORY;
 265         }
 266
 267         /* Do notify operations on the base_name. */
 268         fullpath = talloc_asprintf(
 269                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 270                 fsp->fsp_name->base_name);
 271         if (fullpath == NULL) {
 272                 DEBUG(0, ("talloc_asprintf failed\n"));
 273                 TALLOC_FREE(fsp->notify);
 274                 return NT_STATUS_NO_MEMORY;
 275         }
 276
 277         /*
 278          * Avoid /. at the end of the path name. notify can't deal with it.
 279          */
 280         len = strlen(fullpath);
 281         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 282                 fullpath[len-2] = '\0';
 283         }
 284
 285         subdir_filter = recursive ? filter : 0;
 286
 287         if (fsp->conn->sconn->sys_notify_ctx != NULL) {
 288                 void *sys_notify_handle = NULL;
 289
 290                 status = SMB_VFS_NOTIFY_WATCH(
 291                         fsp->conn, fsp->conn->sconn->sys_notify_ctx,
 292                         fullpath, &filter, &subdir_filter,
 293                         sys_notify_callback, fsp, &sys_notify_handle);
 294
 295                 if (NT_STATUS_IS_OK(status)) {
 296                         talloc_steal(fsp->notify, sys_notify_handle);
 297                 }
 298         }
 299
 300         if ((filter != 0) || (subdir_filter != 0)) {
 301                 status = notify_add(fsp->conn->sconn->notify_ctx,
 302                                     fullpath, filter, subdir_filter,
 303                                     notify_callback, fsp);
 304         }
 305         TALLOC_FREE(fullpath);
 306         return status;
 307 }
 308
 309 NTSTATUS change_notify_add_request(struct smb_request *req,
 310                                 uint32_t max_param,
 311                                 uint32_t filter, bool recursive,
 312                                 struct files_struct *fsp,
 313                                 void (*reply_fn)(struct smb_request *req,
 314                                         NTSTATUS error_code,
 315                                         uint8_t *buf, size_t len))
 316 {
 317         struct notify_change_request *request = NULL;
 318         struct notify_mid_map *map = NULL;
 319         struct smbd_server_connection *sconn = req->sconn;
 320
 321         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 322                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 323
 324         if (!(request = talloc(NULL, struct notify_change_request))
 325             || !(map = talloc(request, struct notify_mid_map))) {
 326                 TALLOC_FREE(request);
 327                 return NT_STATUS_NO_MEMORY;
 328         }
 329
 330         request->mid_map = map;
 331         map->req = request;
 332
 333         request->req = talloc_move(request, &req);
 334         request->max_param = max_param;
 335         request->filter = filter;
 336         request->fsp = fsp;
 337         request->reply_fn = reply_fn;
 338         request->backend_data = NULL;
 339
 340         DLIST_ADD_END(fsp->notify->requests, request,
 341                       struct notify_change_request *);
 342
 343         map->mid = request->req->mid;
 344         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 345
 346         return NT_STATUS_OK;
 347 }
 348
 349 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 350                                          struct notify_change_request *remove_req)
 351 {
 352         files_struct *fsp;
 353         struct notify_change_request *req;
 354
 355         /*
 356          * Paranoia checks, the fsp referenced must must have the request in
 357          * its list of pending requests
 358          */
 359
 360         fsp = remove_req->fsp;
 361         SMB_ASSERT(fsp->notify != NULL);
 362
 363         for (req = fsp->notify->requests; req; req = req->next) {
 364                 if (req == remove_req) {
 365                         break;
 366                 }
 367         }
 368
 369         if (req == NULL) {
 370                 smb_panic("notify_req not found in fsp's requests");
 371         }
 372
 373         DLIST_REMOVE(fsp->notify->requests, req);
 374         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 375         TALLOC_FREE(req);
 376 }
 377
 378 /****************************************************************************
 379  Delete entries by mid from the change notify pending queue. Always send reply.
 380 *****************************************************************************/
 381
 382 void remove_pending_change_notify_requests_by_mid(
 383         struct smbd_server_connection *sconn, uint64_t mid)
 384 {
 385         struct notify_mid_map *map;
 386
 387         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 388                 if (map->mid == mid) {
 389                         break;
 390                 }
 391         }
 392
 393         if (map == NULL) {
 394                 return;
 395         }
 396
 397         change_notify_reply(map->req->req,
 398                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 399         change_notify_remove_request(sconn, map->req);
 400 }
 401
 402 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 403 {
 404         struct smbd_server_connection *sconn = smbreq->sconn;
 405         struct notify_mid_map *map;
 406
 407         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 408                 if (map->req->req == smbreq) {
 409                         break;
 410                 }
 411         }
 412
 413         if (map == NULL) {
 414                 return;
 415         }
 416
 417         change_notify_reply(map->req->req,
 418                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 419         change_notify_remove_request(sconn, map->req);
 420 }
 421
 422 static struct files_struct *smbd_notify_cancel_deleted_fn(
 423         struct files_struct *fsp, void *private_data)
 424 {
 425         struct file_id *fid = talloc_get_type_abort(
 426                 private_data, struct file_id);
 427
 428         if (file_id_equal(&fsp->file_id, fid)) {
 429                 remove_pending_change_notify_requests_by_fid(
 430                         fsp, NT_STATUS_DELETE_PENDING);
 431         }
 432         return NULL;
 433 }
 434
 435 void smbd_notify_cancel_deleted(struct messaging_context *msg,
 436                                 void *private_data, uint32_t msg_type,
 437                                 struct server_id server_id, DATA_BLOB *data)
 438 {
 439         struct smbd_server_connection *sconn = talloc_get_type_abort(
 440                 private_data, struct smbd_server_connection);
 441         struct file_id *fid;
 442         enum ndr_err_code ndr_err;
 443
 444         fid = talloc(talloc_tos(), struct file_id);
 445         if (fid == NULL) {
 446                 DEBUG(1, ("talloc failed\n"));
 447                 return;
 448         }
 449
 450         ndr_err = ndr_pull_struct_blob_all(
 451                 data, fid, fid, (ndr_pull_flags_fn_t)ndr_pull_file_id);
 452         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 453                 DEBUG(10, ("%s: ndr_pull_file_id failed: %s\n", __func__,
 454                            ndr_errstr(ndr_err)));
 455                 goto done;
 456         }
 457
 458         files_forall(sconn, smbd_notify_cancel_deleted_fn, fid);
 459
 460 done:
 461         TALLOC_FREE(fid);
 462 }
 463
 464 /****************************************************************************
 465  Delete entries by fnum from the change notify pending queue.
 466 *****************************************************************************/
 467
 468 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 469                                                   NTSTATUS status)
 470 {
 471         if (fsp->notify == NULL) {
 472                 return;
 473         }
 474
 475         while (fsp->notify->requests != NULL) {
 476                 change_notify_reply(fsp->notify->requests->req,
 477                                     status, 0, NULL,
 478                                     fsp->notify->requests->reply_fn);
 479                 change_notify_remove_request(fsp->conn->sconn,
 480                                              fsp->notify->requests);
 481         }
 482 }
 483
 484 void notify_fname(connection_struct *conn, uint32_t action, uint32_t filter,
 485                   const char *path)
 486 {
 487         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 488
 489         if (path[0] == '.' && path[1] == '/') {
 490                 path += 2;
 491         }
 492
 493         notify_trigger(notify_ctx, action, filter, conn->connectpath, path);
 494 }
 495
 496 static void notify_fsp(files_struct *fsp, struct timespec when,
 497                        uint32_t action, const char *name)
 498 {
 499         struct notify_change_event *change, *changes;
 500         char *tmp;
 501
 502         if (fsp->notify == NULL) {
 503                 /*
 504                  * Nobody is waiting, don't queue
 505                  */
 506                 return;
 507         }
 508
 509         /*
 510          * Someone has triggered a notify previously, queue the change for
 511          * later.
 512          */
 513
 514         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 515                 /*
 516                  * The real number depends on the client buf, just provide a
 517                  * guard against a DoS here.  If name == NULL the CN backend is
 518                  * alerting us to a problem.  Possibly dropped events.  Clear
 519                  * queued changes and send the catch-all response to the client
 520                  * if a request is pending.
 521                  */
 522                 TALLOC_FREE(fsp->notify->changes);
 523                 fsp->notify->num_changes = -1;
 524                 if (fsp->notify->requests != NULL) {
 525                         change_notify_reply(fsp->notify->requests->req,
 526                                             NT_STATUS_OK,
 527                                             fsp->notify->requests->max_param,
 528                                             fsp->notify,
 529                                             fsp->notify->requests->reply_fn);
 530                         change_notify_remove_request(fsp->conn->sconn,
 531                                                      fsp->notify->requests);
 532                 }
 533                 return;
 534         }
 535
 536         /* If we've exceeded the server side queue or received a NULL name
 537          * from the underlying CN implementation, don't queue up any more
 538          * requests until we can send a catch-all response to the client */
 539         if (fsp->notify->num_changes == -1) {
 540                 return;
 541         }
 542
 543         if (!(changes = talloc_realloc(
 544                       fsp->notify, fsp->notify->changes,
 545                       struct notify_change_event,
 546                       fsp->notify->num_changes+1))) {
 547                 DEBUG(0, ("talloc_realloc failed\n"));
 548                 return;
 549         }
 550
 551         fsp->notify->changes = changes;
 552
 553         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 554
 555         if (!(tmp = talloc_strdup(changes, name))) {
 556                 DEBUG(0, ("talloc_strdup failed\n"));
 557                 return;
 558         }
 559
 560         string_replace(tmp, '/', '\\');
 561         change->name = tmp;
 562
 563         change->when = when;
 564         change->action = action;
 565         fsp->notify->num_changes += 1;
 566
 567         if (fsp->notify->requests == NULL) {
 568                 /*
 569                  * Nobody is waiting, so don't send anything. The ot
 570                  */
 571                 return;
 572         }
 573
 574         if (action == NOTIFY_ACTION_OLD_NAME) {
 575                 /*
 576                  * We have to send the two rename events in one reply. So hold
 577                  * the first part back.
 578                  */
 579                 return;
 580         }
 581
 582         /*
 583          * Someone is waiting for the change, trigger the reply immediately.
 584          *
 585          * TODO: do we have to walk the lists of requests pending?
 586          */
 587
 588         change_notify_reply(fsp->notify->requests->req,
 589                             NT_STATUS_OK,
 590                             fsp->notify->requests->max_param,
 591                             fsp->notify,
 592                             fsp->notify->requests->reply_fn);
 593
 594         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 595 }
 596
 597 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32_t filter)
 598 {
 599         char *result = NULL;
 600
 601         result = talloc_strdup(mem_ctx, "");
 602
 603         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 604                 result = talloc_asprintf_append(result, "FILE_NAME|");
 605         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 606                 result = talloc_asprintf_append(result, "DIR_NAME|");
 607         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 608                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 609         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 610                 result = talloc_asprintf_append(result, "SIZE|");
 611         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 612                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 613         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 614                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 615         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 616                 result = talloc_asprintf_append(result, "CREATION|");
 617         if (filter & FILE_NOTIFY_CHANGE_EA)
 618                 result = talloc_asprintf_append(result, "EA|");
 619         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 620                 result = talloc_asprintf_append(result, "SECURITY|");
 621         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 622                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 623         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 624                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 625         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 626                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 627
 628         if (result == NULL) return NULL;
 629         if (*result == '\0') return result;
 630
 631         result[strlen(result)-1] = '\0';
 632         return result;
 633 }
 634
 635 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 636                                                      struct tevent_context *ev)
 637 {
 638         struct sys_notify_context *ctx;
 639
 640         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 641                 DEBUG(0, ("talloc failed\n"));
 642                 return NULL;
 643         }
 644
 645         ctx->ev = ev;
 646         ctx->private_data = NULL;
 647         return ctx;
 648 }