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