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
  27 struct notify_change_event {
  28         struct timespec when;
  29         uint32_t action;
  30         const char *name;
  31 };
  32
  33 struct notify_change_buf {
  34         /*
  35          * If no requests are pending, changes are queued here. Simple array,
  36          * we only append.
  37          */
  38
  39         /*
  40          * num_changes == -1 means that we have got a catch-all change, when
  41          * asked we just return NT_STATUS_OK without specific changes.
  42          */
  43         int num_changes;
  44         struct notify_change_event *changes;
  45
  46         /*
  47          * If no changes are around requests are queued here. Using a linked
  48          * list, because we have to append at the end and delete from the top.
  49          */
  50         struct notify_change_request *requests;
  51 };
  52
  53 struct notify_change_request {
  54         struct notify_change_request *prev, *next;
  55         struct files_struct *fsp;       /* backpointer for cancel by mid */
  56         struct smb_request *req;
  57         uint32 filter;
  58         uint32 max_param;
  59         void (*reply_fn)(struct smb_request *req,
  60                          NTSTATUS error_code,
  61                          uint8_t *buf, size_t len);
  62         struct notify_mid_map *mid_map;
  63         void *backend_data;
  64 };
  65
  66 static void notify_fsp(files_struct *fsp, struct timespec when,
  67                        uint32 action, const char *name);
  68
  69 bool change_notify_fsp_has_changes(struct files_struct *fsp)
  70 {
  71         if (fsp == NULL) {
  72                 return false;
  73         }
  74
  75         if (fsp->notify == NULL) {
  76                 return false;
  77         }
  78
  79         if (fsp->notify->num_changes == 0) {
  80                 return false;
  81         }
  82
  83         return true;
  84 }
  85
  86 /*
  87  * For NTCancel, we need to find the notify_change_request indexed by
  88  * mid. Separate list here.
  89  */
  90
  91 struct notify_mid_map {
  92         struct notify_mid_map *prev, *next;
  93         struct notify_change_request *req;
  94         uint64_t mid;
  95 };
  96
  97 static bool notify_change_record_identical(struct notify_change_event *c1,
  98                                            struct notify_change_event *c2)
  99 {
 100         /* Note this is deliberately case sensitive. */
 101         if (c1->action == c2->action &&
 102                         strcmp(c1->name, c2->name) == 0) {
 103                 return True;
 104         }
 105         return False;
 106 }
 107
 108 static bool notify_marshall_changes(int num_changes,
 109                                 uint32 max_offset,
 110                                 struct notify_change_event *changes,
 111                                 DATA_BLOB *final_blob)
 112 {
 113         int i;
 114
 115         if (num_changes == -1) {
 116                 return false;
 117         }
 118
 119         for (i=0; i<num_changes; i++) {
 120                 enum ndr_err_code ndr_err;
 121                 struct notify_change_event *c;
 122                 struct FILE_NOTIFY_INFORMATION m;
 123                 DATA_BLOB blob;
 124
 125                 /* Coalesce any identical records. */
 126                 while (i+1 < num_changes &&
 127                         notify_change_record_identical(&changes[i],
 128                                                 &changes[i+1])) {
 129                         i++;
 130                 }
 131
 132                 c = &changes[i];
 133
 134                 m.FileName1 = c->name;
 135                 m.FileNameLength = strlen_m(c->name)*2;
 136                 m.Action = c->action;
 137                 m.NextEntryOffset = (i == num_changes-1) ? 0 : ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
 138
 139                 /*
 140                  * Offset to next entry, only if there is one
 141                  */
 142
 143                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
 144                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 145                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 146                         return false;
 147                 }
 148
 149                 if (DEBUGLEVEL >= 10) {
 150                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 151                 }
 152
 153                 if (!data_blob_append(talloc_tos(), final_blob,
 154                                       blob.data, blob.length)) {
 155                         data_blob_free(&blob);
 156                         return false;
 157                 }
 158
 159                 data_blob_free(&blob);
 160
 161                 if (final_blob->length > max_offset) {
 162                         /* Too much data for client. */
 163                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 164                                    "marshall %d bytes\n", (int)max_offset,
 165                                    (int)final_blob->length));
 166                         return False;
 167                 }
 168         }
 169
 170         return True;
 171 }
 172
 173 static int compare_notify_change_events(const void *p1, const void *p2)
 174 {
 175         const struct notify_change_event *e1 = p1;
 176         const struct notify_change_event *e2 = p2;
 177
 178         return timespec_compare(&e1->when, &e2->when);
 179 }
 180
 181 /****************************************************************************
 182  Setup the common parts of the return packet and send it.
 183 *****************************************************************************/
 184
 185 void change_notify_reply(struct smb_request *req,
 186                          NTSTATUS error_code,
 187                          uint32_t max_param,
 188                          struct notify_change_buf *notify_buf,
 189                          void (*reply_fn)(struct smb_request *req,
 190                                           NTSTATUS error_code,
 191                                           uint8_t *buf, size_t len))
 192 {
 193         DATA_BLOB blob = data_blob_null;
 194
 195         if (!NT_STATUS_IS_OK(error_code)) {
 196                 reply_fn(req, error_code, NULL, 0);
 197                 return;
 198         }
 199
 200         if (max_param == 0 || notify_buf == NULL) {
 201                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 202                 return;
 203         }
 204
 205         /*
 206          * Sort the notifies by timestamp when the event happened to avoid
 207          * coalescing and thus dropping events in notify_marshall_changes.
 208          */
 209
 210         qsort(notify_buf->changes, notify_buf->num_changes,
 211               sizeof(*(notify_buf->changes)), compare_notify_change_events);
 212
 213         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 214                                         notify_buf->changes, &blob)) {
 215                 /*
 216                  * We exceed what the client is willing to accept. Send
 217                  * nothing.
 218                  */
 219                 data_blob_free(&blob);
 220         }
 221
 222         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 223
 224         data_blob_free(&blob);
 225
 226         TALLOC_FREE(notify_buf->changes);
 227         notify_buf->num_changes = 0;
 228 }
 229
 230 static void notify_callback(void *private_data, struct timespec when,
 231                             const struct notify_event *e)
 232 {
 233         files_struct *fsp = (files_struct *)private_data;
 234         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 235         notify_fsp(fsp, when, e->action, e->path);
 236 }
 237
 238 static void sys_notify_callback(struct sys_notify_context *ctx,
 239                                 void *private_data,
 240                                 struct notify_event *e)
 241 {
 242         files_struct *fsp = (files_struct *)private_data;
 243         DEBUG(10, ("sys_notify_callback called for %s\n", fsp_str_dbg(fsp)));
 244         notify_fsp(fsp, timespec_current(), e->action, e->path);
 245 }
 246
 247 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 248                               bool recursive)
 249 {
 250         char *fullpath;
 251         size_t len;
 252         uint32_t subdir_filter;
 253         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 254
 255         if (fsp->notify != NULL) {
 256                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 257                           "fname = %s\n", fsp->fsp_name->base_name));
 258                 return NT_STATUS_INVALID_PARAMETER;
 259         }
 260
 261         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 262                 DEBUG(0, ("talloc failed\n"));
 263                 return NT_STATUS_NO_MEMORY;
 264         }
 265
 266         /* Do notify operations on the base_name. */
 267         fullpath = talloc_asprintf(
 268                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 269                 fsp->fsp_name->base_name);
 270         if (fullpath == NULL) {
 271                 DEBUG(0, ("talloc_asprintf failed\n"));
 272                 TALLOC_FREE(fsp->notify);
 273                 return NT_STATUS_NO_MEMORY;
 274         }
 275
 276         /*
 277          * Avoid /. at the end of the path name. notify can't deal with it.
 278          */
 279         len = strlen(fullpath);
 280         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 281                 fullpath[len-2] = '\0';
 282         }
 283
 284         subdir_filter = recursive ? filter : 0;
 285
 286         if (fsp->conn->sconn->sys_notify_ctx != NULL) {
 287                 void *sys_notify_handle = NULL;
 288
 289                 status = SMB_VFS_NOTIFY_WATCH(
 290                         fsp->conn, fsp->conn->sconn->sys_notify_ctx,
 291                         fullpath, &filter, &subdir_filter,
 292                         sys_notify_callback, fsp, &sys_notify_handle);
 293
 294                 if (NT_STATUS_IS_OK(status)) {
 295                         talloc_steal(fsp->notify, sys_notify_handle);
 296                 }
 297         }
 298
 299         if ((filter != 0) || (subdir_filter != 0)) {
 300                 status = notify_add(fsp->conn->sconn->notify_ctx,
 301                                     fullpath, filter, subdir_filter,
 302                                     notify_callback, fsp);
 303         }
 304         TALLOC_FREE(fullpath);
 305         return status;
 306 }
 307
 308 NTSTATUS change_notify_add_request(struct smb_request *req,
 309                                 uint32 max_param,
 310                                 uint32 filter, bool recursive,
 311                                 struct files_struct *fsp,
 312                                 void (*reply_fn)(struct smb_request *req,
 313                                         NTSTATUS error_code,
 314                                         uint8_t *buf, size_t len))
 315 {
 316         struct notify_change_request *request = NULL;
 317         struct notify_mid_map *map = NULL;
 318         struct smbd_server_connection *sconn = req->sconn;
 319
 320         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 321                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 322
 323         if (!(request = talloc(NULL, struct notify_change_request))
 324             || !(map = talloc(request, struct notify_mid_map))) {
 325                 TALLOC_FREE(request);
 326                 return NT_STATUS_NO_MEMORY;
 327         }
 328
 329         request->mid_map = map;
 330         map->req = request;
 331
 332         request->req = talloc_move(request, &req);
 333         request->max_param = max_param;
 334         request->filter = filter;
 335         request->fsp = fsp;
 336         request->reply_fn = reply_fn;
 337         request->backend_data = NULL;
 338
 339         DLIST_ADD_END(fsp->notify->requests, request,
 340                       struct notify_change_request *);
 341
 342         map->mid = request->req->mid;
 343         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 344
 345         return NT_STATUS_OK;
 346 }
 347
 348 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 349                                          struct notify_change_request *remove_req)
 350 {
 351         files_struct *fsp;
 352         struct notify_change_request *req;
 353
 354         /*
 355          * Paranoia checks, the fsp referenced must must have the request in
 356          * its list of pending requests
 357          */
 358
 359         fsp = remove_req->fsp;
 360         SMB_ASSERT(fsp->notify != NULL);
 361
 362         for (req = fsp->notify->requests; req; req = req->next) {
 363                 if (req == remove_req) {
 364                         break;
 365                 }
 366         }
 367
 368         if (req == NULL) {
 369                 smb_panic("notify_req not found in fsp's requests");
 370         }
 371
 372         DLIST_REMOVE(fsp->notify->requests, req);
 373         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 374         TALLOC_FREE(req);
 375 }
 376
 377 /****************************************************************************
 378  Delete entries by mid from the change notify pending queue. Always send reply.
 379 *****************************************************************************/
 380
 381 void remove_pending_change_notify_requests_by_mid(
 382         struct smbd_server_connection *sconn, uint64_t mid)
 383 {
 384         struct notify_mid_map *map;
 385
 386         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 387                 if (map->mid == mid) {
 388                         break;
 389                 }
 390         }
 391
 392         if (map == NULL) {
 393                 return;
 394         }
 395
 396         change_notify_reply(map->req->req,
 397                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 398         change_notify_remove_request(sconn, map->req);
 399 }
 400
 401 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 402 {
 403         struct smbd_server_connection *sconn = smbreq->sconn;
 404         struct notify_mid_map *map;
 405
 406         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 407                 if (map->req->req == smbreq) {
 408                         break;
 409                 }
 410         }
 411
 412         if (map == NULL) {
 413                 return;
 414         }
 415
 416         change_notify_reply(map->req->req,
 417                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 418         change_notify_remove_request(sconn, map->req);
 419 }
 420
 421 /****************************************************************************
 422  Delete entries by fnum from the change notify pending queue.
 423 *****************************************************************************/
 424
 425 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 426                                                   NTSTATUS status)
 427 {
 428         if (fsp->notify == NULL) {
 429                 return;
 430         }
 431
 432         while (fsp->notify->requests != NULL) {
 433                 change_notify_reply(fsp->notify->requests->req,
 434                                     status, 0, NULL,
 435                                     fsp->notify->requests->reply_fn);
 436                 change_notify_remove_request(fsp->conn->sconn,
 437                                              fsp->notify->requests);
 438         }
 439 }
 440
 441 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 442                   const char *path)
 443 {
 444         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 445         char *fullpath, *to_free;
 446         char tmpbuf[PATH_MAX];
 447         ssize_t len;
 448
 449         if (path[0] == '.' && path[1] == '/') {
 450                 path += 2;
 451         }
 452         len = full_path_tos(conn->connectpath, path, tmpbuf, sizeof(tmpbuf),
 453                             &fullpath, &to_free);
 454         if (len == -1) {
 455                 DEBUG(0, ("full_path_tos failed\n"));
 456                 return;
 457         }
 458         notify_trigger(notify_ctx, action, filter, fullpath);
 459         TALLOC_FREE(to_free);
 460 }
 461
 462 static void notify_fsp(files_struct *fsp, struct timespec when,
 463                        uint32 action, const char *name)
 464 {
 465         struct notify_change_event *change, *changes;
 466         char *tmp;
 467
 468         if (fsp->notify == NULL) {
 469                 /*
 470                  * Nobody is waiting, don't queue
 471                  */
 472                 return;
 473         }
 474
 475         /*
 476          * Someone has triggered a notify previously, queue the change for
 477          * later.
 478          */
 479
 480         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 481                 /*
 482                  * The real number depends on the client buf, just provide a
 483                  * guard against a DoS here.  If name == NULL the CN backend is
 484                  * alerting us to a problem.  Possibly dropped events.  Clear
 485                  * queued changes and send the catch-all response to the client
 486                  * if a request is pending.
 487                  */
 488                 TALLOC_FREE(fsp->notify->changes);
 489                 fsp->notify->num_changes = -1;
 490                 if (fsp->notify->requests != NULL) {
 491                         change_notify_reply(fsp->notify->requests->req,
 492                                             NT_STATUS_OK,
 493                                             fsp->notify->requests->max_param,
 494                                             fsp->notify,
 495                                             fsp->notify->requests->reply_fn);
 496                         change_notify_remove_request(fsp->conn->sconn,
 497                                                      fsp->notify->requests);
 498                 }
 499                 return;
 500         }
 501
 502         /* If we've exceeded the server side queue or received a NULL name
 503          * from the underlying CN implementation, don't queue up any more
 504          * requests until we can send a catch-all response to the client */
 505         if (fsp->notify->num_changes == -1) {
 506                 return;
 507         }
 508
 509         if (!(changes = talloc_realloc(
 510                       fsp->notify, fsp->notify->changes,
 511                       struct notify_change_event,
 512                       fsp->notify->num_changes+1))) {
 513                 DEBUG(0, ("talloc_realloc failed\n"));
 514                 return;
 515         }
 516
 517         fsp->notify->changes = changes;
 518
 519         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 520
 521         if (!(tmp = talloc_strdup(changes, name))) {
 522                 DEBUG(0, ("talloc_strdup failed\n"));
 523                 return;
 524         }
 525
 526         string_replace(tmp, '/', '\\');
 527         change->name = tmp;
 528
 529         change->when = when;
 530         change->action = action;
 531         fsp->notify->num_changes += 1;
 532
 533         if (fsp->notify->requests == NULL) {
 534                 /*
 535                  * Nobody is waiting, so don't send anything. The ot
 536                  */
 537                 return;
 538         }
 539
 540         if (action == NOTIFY_ACTION_OLD_NAME) {
 541                 /*
 542                  * We have to send the two rename events in one reply. So hold
 543                  * the first part back.
 544                  */
 545                 return;
 546         }
 547
 548         /*
 549          * Someone is waiting for the change, trigger the reply immediately.
 550          *
 551          * TODO: do we have to walk the lists of requests pending?
 552          */
 553
 554         change_notify_reply(fsp->notify->requests->req,
 555                             NT_STATUS_OK,
 556                             fsp->notify->requests->max_param,
 557                             fsp->notify,
 558                             fsp->notify->requests->reply_fn);
 559
 560         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 561 }
 562
 563 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 564 {
 565         char *result = NULL;
 566
 567         result = talloc_strdup(mem_ctx, "");
 568
 569         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 570                 result = talloc_asprintf_append(result, "FILE_NAME|");
 571         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 572                 result = talloc_asprintf_append(result, "DIR_NAME|");
 573         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 574                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 575         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 576                 result = talloc_asprintf_append(result, "SIZE|");
 577         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 578                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 579         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 580                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 581         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 582                 result = talloc_asprintf_append(result, "CREATION|");
 583         if (filter & FILE_NOTIFY_CHANGE_EA)
 584                 result = talloc_asprintf_append(result, "EA|");
 585         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 586                 result = talloc_asprintf_append(result, "SECURITY|");
 587         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 588                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 589         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 590                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 591         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 592                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 593
 594         if (result == NULL) return NULL;
 595         if (*result == '\0') return result;
 596
 597         result[strlen(result)-1] = '\0';
 598         return result;
 599 }
 600
 601 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 602                                                      struct tevent_context *ev)
 603 {
 604         struct sys_notify_context *ctx;
 605
 606         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 607                 DEBUG(0, ("talloc failed\n"));
 608                 return NULL;
 609         }
 610
 611         ctx->ev = ev;
 612         ctx->private_data = NULL;
 613         return ctx;
 614 }