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 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 178                               bool recursive)
 179 {
 180         char *fullpath;
 181         size_t len;
 182         struct notify_entry e;
 183         NTSTATUS status;
 184
 185         if (fsp->notify != NULL) {
 186                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 187                           "fname = %s\n", fsp->fsp_name->base_name));
 188                 return NT_STATUS_INVALID_PARAMETER;
 189         }
 190
 191         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 192                 DEBUG(0, ("talloc failed\n"));
 193                 return NT_STATUS_NO_MEMORY;
 194         }
 195
 196         /* Do notify operations on the base_name. */
 197         fullpath = talloc_asprintf(
 198                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 199                 fsp->fsp_name->base_name);
 200         if (fullpath == NULL) {
 201                 DEBUG(0, ("talloc_asprintf failed\n"));
 202                 TALLOC_FREE(fsp->notify);
 203                 return NT_STATUS_NO_MEMORY;
 204         }
 205
 206         /*
 207          * Avoid /. at the end of the path name. notify can't deal with it.
 208          */
 209         len = strlen(fullpath);
 210         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 211                 fullpath[len-2] = '\0';
 212         }
 213
 214         ZERO_STRUCT(e);
 215         e.path = fullpath;
 216         e.dir_fd = fsp->fh->fd;
 217         e.dir_id = fsp->file_id;
 218         e.filter = filter;
 219         e.subdir_filter = 0;
 220         if (recursive) {
 221                 e.subdir_filter = filter;
 222         }
 223
 224         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 225         TALLOC_FREE(fullpath);
 226
 227         return status;
 228 }
 229
 230 NTSTATUS change_notify_add_request(struct smb_request *req,
 231                                 uint32 max_param,
 232                                 uint32 filter, bool recursive,
 233                                 struct files_struct *fsp,
 234                                 void (*reply_fn)(struct smb_request *req,
 235                                         NTSTATUS error_code,
 236                                         uint8_t *buf, size_t len))
 237 {
 238         struct notify_change_request *request = NULL;
 239         struct notify_mid_map *map = NULL;
 240         struct smbd_server_connection *sconn = req->sconn;
 241
 242         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 243                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 244
 245         if (!(request = talloc(NULL, struct notify_change_request))
 246             || !(map = talloc(request, struct notify_mid_map))) {
 247                 TALLOC_FREE(request);
 248                 return NT_STATUS_NO_MEMORY;
 249         }
 250
 251         request->mid_map = map;
 252         map->req = request;
 253
 254         request->req = talloc_move(request, &req);
 255         request->max_param = max_param;
 256         request->filter = filter;
 257         request->fsp = fsp;
 258         request->reply_fn = reply_fn;
 259         request->backend_data = NULL;
 260
 261         DLIST_ADD_END(fsp->notify->requests, request,
 262                       struct notify_change_request *);
 263
 264         map->mid = request->req->mid;
 265         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 266
 267         return NT_STATUS_OK;
 268 }
 269
 270 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 271                                          struct notify_change_request *remove_req)
 272 {
 273         files_struct *fsp;
 274         struct notify_change_request *req;
 275
 276         /*
 277          * Paranoia checks, the fsp referenced must must have the request in
 278          * its list of pending requests
 279          */
 280
 281         fsp = remove_req->fsp;
 282         SMB_ASSERT(fsp->notify != NULL);
 283
 284         for (req = fsp->notify->requests; req; req = req->next) {
 285                 if (req == remove_req) {
 286                         break;
 287                 }
 288         }
 289
 290         if (req == NULL) {
 291                 smb_panic("notify_req not found in fsp's requests");
 292         }
 293
 294         DLIST_REMOVE(fsp->notify->requests, req);
 295         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 296         TALLOC_FREE(req);
 297 }
 298
 299 /****************************************************************************
 300  Delete entries by mid from the change notify pending queue. Always send reply.
 301 *****************************************************************************/
 302
 303 void remove_pending_change_notify_requests_by_mid(
 304         struct smbd_server_connection *sconn, uint64_t mid)
 305 {
 306         struct notify_mid_map *map;
 307
 308         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 309                 if (map->mid == mid) {
 310                         break;
 311                 }
 312         }
 313
 314         if (map == NULL) {
 315                 return;
 316         }
 317
 318         change_notify_reply(map->req->req,
 319                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 320         change_notify_remove_request(sconn, map->req);
 321 }
 322
 323 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 324 {
 325         struct smbd_server_connection *sconn = smbreq->sconn;
 326         struct notify_mid_map *map;
 327
 328         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 329                 if (map->req->req == smbreq) {
 330                         break;
 331                 }
 332         }
 333
 334         if (map == NULL) {
 335                 return;
 336         }
 337
 338         change_notify_reply(map->req->req,
 339                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 340         change_notify_remove_request(sconn, map->req);
 341 }
 342
 343 /****************************************************************************
 344  Delete entries by fnum from the change notify pending queue.
 345 *****************************************************************************/
 346
 347 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 348                                                   NTSTATUS status)
 349 {
 350         if (fsp->notify == NULL) {
 351                 return;
 352         }
 353
 354         while (fsp->notify->requests != NULL) {
 355                 change_notify_reply(fsp->notify->requests->req,
 356                                     status, 0, NULL,
 357                                     fsp->notify->requests->reply_fn);
 358                 change_notify_remove_request(fsp->conn->sconn,
 359                                              fsp->notify->requests);
 360         }
 361 }
 362
 363 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 364                   const char *path)
 365 {
 366         char *fullpath;
 367         char *parent;
 368         const char *name;
 369
 370         if (path[0] == '.' && path[1] == '/') {
 371                 path += 2;
 372         }
 373         if (parent_dirname(talloc_tos(), path, &parent, &name)) {
 374                 struct smb_filename smb_fname_parent;
 375
 376                 ZERO_STRUCT(smb_fname_parent);
 377                 smb_fname_parent.base_name = parent;
 378
 379                 if (SMB_VFS_STAT(conn, &smb_fname_parent) != -1) {
 380                         notify_onelevel(conn->notify_ctx, action, filter,
 381                             SMB_VFS_FILE_ID_CREATE(conn, &smb_fname_parent.st),
 382                             name);
 383                 }
 384         }
 385
 386         fullpath = talloc_asprintf(talloc_tos(), "%s/%s", conn->connectpath,
 387                                    path);
 388         if (fullpath == NULL) {
 389                 DEBUG(0, ("asprintf failed\n"));
 390                 return;
 391         }
 392         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 393         TALLOC_FREE(fullpath);
 394 }
 395
 396 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 397 {
 398         struct notify_change *change, *changes;
 399         char *tmp;
 400
 401         if (fsp->notify == NULL) {
 402                 /*
 403                  * Nobody is waiting, don't queue
 404                  */
 405                 return;
 406         }
 407
 408         /*
 409          * Someone has triggered a notify previously, queue the change for
 410          * later.
 411          */
 412
 413         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 414                 /*
 415                  * The real number depends on the client buf, just provide a
 416                  * guard against a DoS here.  If name == NULL the CN backend is
 417                  * alerting us to a problem.  Possibly dropped events.  Clear
 418                  * queued changes and send the catch-all response to the client
 419                  * if a request is pending.
 420                  */
 421                 TALLOC_FREE(fsp->notify->changes);
 422                 fsp->notify->num_changes = -1;
 423                 if (fsp->notify->requests != NULL) {
 424                         change_notify_reply(fsp->notify->requests->req,
 425                                             NT_STATUS_OK,
 426                                             fsp->notify->requests->max_param,
 427                                             fsp->notify,
 428                                             fsp->notify->requests->reply_fn);
 429                         change_notify_remove_request(fsp->conn->sconn,
 430                                                      fsp->notify->requests);
 431                 }
 432                 return;
 433         }
 434
 435         /* If we've exceeded the server side queue or received a NULL name
 436          * from the underlying CN implementation, don't queue up any more
 437          * requests until we can send a catch-all response to the client */
 438         if (fsp->notify->num_changes == -1) {
 439                 return;
 440         }
 441
 442         if (!(changes = talloc_realloc(
 443                       fsp->notify, fsp->notify->changes,
 444                       struct notify_change, fsp->notify->num_changes+1))) {
 445                 DEBUG(0, ("talloc_realloc failed\n"));
 446                 return;
 447         }
 448
 449         fsp->notify->changes = changes;
 450
 451         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 452
 453         if (!(tmp = talloc_strdup(changes, name))) {
 454                 DEBUG(0, ("talloc_strdup failed\n"));
 455                 return;
 456         }
 457
 458         string_replace(tmp, '/', '\\');
 459         change->name = tmp;
 460
 461         change->action = action;
 462         fsp->notify->num_changes += 1;
 463
 464         if (fsp->notify->requests == NULL) {
 465                 /*
 466                  * Nobody is waiting, so don't send anything. The ot
 467                  */
 468                 return;
 469         }
 470
 471         if (action == NOTIFY_ACTION_OLD_NAME) {
 472                 /*
 473                  * We have to send the two rename events in one reply. So hold
 474                  * the first part back.
 475                  */
 476                 return;
 477         }
 478
 479         /*
 480          * Someone is waiting for the change, trigger the reply immediately.
 481          *
 482          * TODO: do we have to walk the lists of requests pending?
 483          */
 484
 485         change_notify_reply(fsp->notify->requests->req,
 486                             NT_STATUS_OK,
 487                             fsp->notify->requests->max_param,
 488                             fsp->notify,
 489                             fsp->notify->requests->reply_fn);
 490
 491         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 492 }
 493
 494 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 495 {
 496         char *result = NULL;
 497
 498         result = talloc_strdup(mem_ctx, "");
 499
 500         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 501                 result = talloc_asprintf_append(result, "FILE_NAME|");
 502         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 503                 result = talloc_asprintf_append(result, "DIR_NAME|");
 504         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 505                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 506         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 507                 result = talloc_asprintf_append(result, "SIZE|");
 508         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 509                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 510         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 511                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 512         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 513                 result = talloc_asprintf_append(result, "CREATION|");
 514         if (filter & FILE_NOTIFY_CHANGE_EA)
 515                 result = talloc_asprintf_append(result, "EA|");
 516         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 517                 result = talloc_asprintf_append(result, "SECURITY|");
 518         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 519                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 520         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 521                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 522         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 523                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 524
 525         if (result == NULL) return NULL;
 526         if (*result == '\0') return result;
 527
 528         result[strlen(result)-1] = '\0';
 529         return result;
 530 }
 531
 532 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 533                                                      TALLOC_CTX *mem_ctx,
 534                                                      struct event_context *ev)
 535 {
 536         struct sys_notify_context *ctx;
 537
 538         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 539                 DEBUG(0, ("talloc failed\n"));
 540                 return NULL;
 541         }
 542
 543         ctx->ev = ev;
 544         ctx->conn = conn;
 545         ctx->private_data = NULL;
 546         return ctx;
 547 }
 548
 549 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 550                           struct notify_entry *e,
 551                           const char *path,
 552                           void (*callback)(struct sys_notify_context *ctx,
 553                                            void *private_data,
 554                                            struct notify_event *ev),
 555                           void *private_data, void *handle)
 556 {
 557         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, path, callback,
 558                                     private_data, handle);
 559 }
 560