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