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