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 /****************************************************************************
 174  Setup the common parts of the return packet and send it.
 175 *****************************************************************************/
 176
 177 void change_notify_reply(struct smb_request *req,
 178                          NTSTATUS error_code,
 179                          uint32_t max_param,
 180                          struct notify_change_buf *notify_buf,
 181                          void (*reply_fn)(struct smb_request *req,
 182                                           NTSTATUS error_code,
 183                                           uint8_t *buf, size_t len))
 184 {
 185         DATA_BLOB blob = data_blob_null;
 186
 187         if (!NT_STATUS_IS_OK(error_code)) {
 188                 reply_fn(req, error_code, NULL, 0);
 189                 return;
 190         }
 191
 192         if (max_param == 0 || notify_buf == NULL) {
 193                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 194                 return;
 195         }
 196
 197         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 198                                         notify_buf->changes, &blob)) {
 199                 /*
 200                  * We exceed what the client is willing to accept. Send
 201                  * nothing.
 202                  */
 203                 data_blob_free(&blob);
 204         }
 205
 206         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 207
 208         data_blob_free(&blob);
 209
 210         TALLOC_FREE(notify_buf->changes);
 211         notify_buf->num_changes = 0;
 212 }
 213
 214 static void notify_callback(void *private_data, struct timespec when,
 215                             const struct notify_event *e)
 216 {
 217         files_struct *fsp = (files_struct *)private_data;
 218         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 219         notify_fsp(fsp, when, e->action, e->path);
 220 }
 221
 222 static void sys_notify_callback(struct sys_notify_context *ctx,
 223                                 void *private_data,
 224                                 struct notify_event *e)
 225 {
 226         files_struct *fsp = (files_struct *)private_data;
 227         DEBUG(10, ("sys_notify_callback called for %s\n", fsp_str_dbg(fsp)));
 228         notify_fsp(fsp, timespec_current(), e->action, e->path);
 229 }
 230
 231 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 232                               bool recursive)
 233 {
 234         char *fullpath;
 235         size_t len;
 236         uint32_t subdir_filter;
 237         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 238
 239         if (fsp->notify != NULL) {
 240                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 241                           "fname = %s\n", fsp->fsp_name->base_name));
 242                 return NT_STATUS_INVALID_PARAMETER;
 243         }
 244
 245         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 246                 DEBUG(0, ("talloc failed\n"));
 247                 return NT_STATUS_NO_MEMORY;
 248         }
 249
 250         /* Do notify operations on the base_name. */
 251         fullpath = talloc_asprintf(
 252                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 253                 fsp->fsp_name->base_name);
 254         if (fullpath == NULL) {
 255                 DEBUG(0, ("talloc_asprintf failed\n"));
 256                 TALLOC_FREE(fsp->notify);
 257                 return NT_STATUS_NO_MEMORY;
 258         }
 259
 260         /*
 261          * Avoid /. at the end of the path name. notify can't deal with it.
 262          */
 263         len = strlen(fullpath);
 264         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 265                 fullpath[len-2] = '\0';
 266         }
 267
 268         subdir_filter = recursive ? filter : 0;
 269
 270         if (fsp->conn->sconn->sys_notify_ctx != NULL) {
 271                 void *sys_notify_handle = NULL;
 272
 273                 status = SMB_VFS_NOTIFY_WATCH(
 274                         fsp->conn, fsp->conn->sconn->sys_notify_ctx,
 275                         fullpath, &filter, &subdir_filter,
 276                         sys_notify_callback, fsp, &sys_notify_handle);
 277
 278                 if (NT_STATUS_IS_OK(status)) {
 279                         talloc_steal(fsp->notify, sys_notify_handle);
 280                 }
 281         }
 282
 283         if ((filter != 0) || (subdir_filter != 0)) {
 284                 status = notify_add(fsp->conn->sconn->notify_ctx,
 285                                     fullpath, filter, subdir_filter,
 286                                     notify_callback, fsp);
 287         }
 288         TALLOC_FREE(fullpath);
 289         return status;
 290 }
 291
 292 NTSTATUS change_notify_add_request(struct smb_request *req,
 293                                 uint32 max_param,
 294                                 uint32 filter, bool recursive,
 295                                 struct files_struct *fsp,
 296                                 void (*reply_fn)(struct smb_request *req,
 297                                         NTSTATUS error_code,
 298                                         uint8_t *buf, size_t len))
 299 {
 300         struct notify_change_request *request = NULL;
 301         struct notify_mid_map *map = NULL;
 302         struct smbd_server_connection *sconn = req->sconn;
 303
 304         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 305                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 306
 307         if (!(request = talloc(NULL, struct notify_change_request))
 308             || !(map = talloc(request, struct notify_mid_map))) {
 309                 TALLOC_FREE(request);
 310                 return NT_STATUS_NO_MEMORY;
 311         }
 312
 313         request->mid_map = map;
 314         map->req = request;
 315
 316         request->req = talloc_move(request, &req);
 317         request->max_param = max_param;
 318         request->filter = filter;
 319         request->fsp = fsp;
 320         request->reply_fn = reply_fn;
 321         request->backend_data = NULL;
 322
 323         DLIST_ADD_END(fsp->notify->requests, request,
 324                       struct notify_change_request *);
 325
 326         map->mid = request->req->mid;
 327         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 328
 329         return NT_STATUS_OK;
 330 }
 331
 332 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 333                                          struct notify_change_request *remove_req)
 334 {
 335         files_struct *fsp;
 336         struct notify_change_request *req;
 337
 338         /*
 339          * Paranoia checks, the fsp referenced must must have the request in
 340          * its list of pending requests
 341          */
 342
 343         fsp = remove_req->fsp;
 344         SMB_ASSERT(fsp->notify != NULL);
 345
 346         for (req = fsp->notify->requests; req; req = req->next) {
 347                 if (req == remove_req) {
 348                         break;
 349                 }
 350         }
 351
 352         if (req == NULL) {
 353                 smb_panic("notify_req not found in fsp's requests");
 354         }
 355
 356         DLIST_REMOVE(fsp->notify->requests, req);
 357         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 358         TALLOC_FREE(req);
 359 }
 360
 361 /****************************************************************************
 362  Delete entries by mid from the change notify pending queue. Always send reply.
 363 *****************************************************************************/
 364
 365 void remove_pending_change_notify_requests_by_mid(
 366         struct smbd_server_connection *sconn, uint64_t mid)
 367 {
 368         struct notify_mid_map *map;
 369
 370         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 371                 if (map->mid == mid) {
 372                         break;
 373                 }
 374         }
 375
 376         if (map == NULL) {
 377                 return;
 378         }
 379
 380         change_notify_reply(map->req->req,
 381                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 382         change_notify_remove_request(sconn, map->req);
 383 }
 384
 385 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 386 {
 387         struct smbd_server_connection *sconn = smbreq->sconn;
 388         struct notify_mid_map *map;
 389
 390         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 391                 if (map->req->req == smbreq) {
 392                         break;
 393                 }
 394         }
 395
 396         if (map == NULL) {
 397                 return;
 398         }
 399
 400         change_notify_reply(map->req->req,
 401                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 402         change_notify_remove_request(sconn, map->req);
 403 }
 404
 405 /****************************************************************************
 406  Delete entries by fnum from the change notify pending queue.
 407 *****************************************************************************/
 408
 409 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 410                                                   NTSTATUS status)
 411 {
 412         if (fsp->notify == NULL) {
 413                 return;
 414         }
 415
 416         while (fsp->notify->requests != NULL) {
 417                 change_notify_reply(fsp->notify->requests->req,
 418                                     status, 0, NULL,
 419                                     fsp->notify->requests->reply_fn);
 420                 change_notify_remove_request(fsp->conn->sconn,
 421                                              fsp->notify->requests);
 422         }
 423 }
 424
 425 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 426                   const char *path)
 427 {
 428         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 429         char *fullpath, *to_free;
 430         char tmpbuf[PATH_MAX];
 431         ssize_t len;
 432
 433         if (path[0] == '.' && path[1] == '/') {
 434                 path += 2;
 435         }
 436         len = full_path_tos(conn->connectpath, path, tmpbuf, sizeof(tmpbuf),
 437                             &fullpath, &to_free);
 438         if (len == -1) {
 439                 DEBUG(0, ("full_path_tos failed\n"));
 440                 return;
 441         }
 442         notify_trigger(notify_ctx, action, filter, fullpath);
 443         TALLOC_FREE(to_free);
 444 }
 445
 446 static void notify_fsp(files_struct *fsp, struct timespec when,
 447                        uint32 action, const char *name)
 448 {
 449         struct notify_change_event *change, *changes;
 450         char *tmp;
 451
 452         if (fsp->notify == NULL) {
 453                 /*
 454                  * Nobody is waiting, don't queue
 455                  */
 456                 return;
 457         }
 458
 459         /*
 460          * Someone has triggered a notify previously, queue the change for
 461          * later.
 462          */
 463
 464         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 465                 /*
 466                  * The real number depends on the client buf, just provide a
 467                  * guard against a DoS here.  If name == NULL the CN backend is
 468                  * alerting us to a problem.  Possibly dropped events.  Clear
 469                  * queued changes and send the catch-all response to the client
 470                  * if a request is pending.
 471                  */
 472                 TALLOC_FREE(fsp->notify->changes);
 473                 fsp->notify->num_changes = -1;
 474                 if (fsp->notify->requests != NULL) {
 475                         change_notify_reply(fsp->notify->requests->req,
 476                                             NT_STATUS_OK,
 477                                             fsp->notify->requests->max_param,
 478                                             fsp->notify,
 479                                             fsp->notify->requests->reply_fn);
 480                         change_notify_remove_request(fsp->conn->sconn,
 481                                                      fsp->notify->requests);
 482                 }
 483                 return;
 484         }
 485
 486         /* If we've exceeded the server side queue or received a NULL name
 487          * from the underlying CN implementation, don't queue up any more
 488          * requests until we can send a catch-all response to the client */
 489         if (fsp->notify->num_changes == -1) {
 490                 return;
 491         }
 492
 493         if (!(changes = talloc_realloc(
 494                       fsp->notify, fsp->notify->changes,
 495                       struct notify_change_event,
 496                       fsp->notify->num_changes+1))) {
 497                 DEBUG(0, ("talloc_realloc failed\n"));
 498                 return;
 499         }
 500
 501         fsp->notify->changes = changes;
 502
 503         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 504
 505         if (!(tmp = talloc_strdup(changes, name))) {
 506                 DEBUG(0, ("talloc_strdup failed\n"));
 507                 return;
 508         }
 509
 510         string_replace(tmp, '/', '\\');
 511         change->name = tmp;
 512
 513         change->when = when;
 514         change->action = action;
 515         fsp->notify->num_changes += 1;
 516
 517         if (fsp->notify->requests == NULL) {
 518                 /*
 519                  * Nobody is waiting, so don't send anything. The ot
 520                  */
 521                 return;
 522         }
 523
 524         if (action == NOTIFY_ACTION_OLD_NAME) {
 525                 /*
 526                  * We have to send the two rename events in one reply. So hold
 527                  * the first part back.
 528                  */
 529                 return;
 530         }
 531
 532         /*
 533          * Someone is waiting for the change, trigger the reply immediately.
 534          *
 535          * TODO: do we have to walk the lists of requests pending?
 536          */
 537
 538         change_notify_reply(fsp->notify->requests->req,
 539                             NT_STATUS_OK,
 540                             fsp->notify->requests->max_param,
 541                             fsp->notify,
 542                             fsp->notify->requests->reply_fn);
 543
 544         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 545 }
 546
 547 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 548 {
 549         char *result = NULL;
 550
 551         result = talloc_strdup(mem_ctx, "");
 552
 553         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 554                 result = talloc_asprintf_append(result, "FILE_NAME|");
 555         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 556                 result = talloc_asprintf_append(result, "DIR_NAME|");
 557         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 558                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 559         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 560                 result = talloc_asprintf_append(result, "SIZE|");
 561         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 562                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 563         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 564                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 565         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 566                 result = talloc_asprintf_append(result, "CREATION|");
 567         if (filter & FILE_NOTIFY_CHANGE_EA)
 568                 result = talloc_asprintf_append(result, "EA|");
 569         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 570                 result = talloc_asprintf_append(result, "SECURITY|");
 571         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 572                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 573         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 574                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 575         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 576                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 577
 578         if (result == NULL) return NULL;
 579         if (*result == '\0') return result;
 580
 581         result[strlen(result)-1] = '\0';
 582         return result;
 583 }
 584
 585 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 586                                                      struct tevent_context *ev)
 587 {
 588         struct sys_notify_context *ctx;
 589
 590         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 591                 DEBUG(0, ("talloc failed\n"));
 592                 return NULL;
 593         }
 594
 595         ctx->ev = ev;
 596         ctx->private_data = NULL;
 597         return ctx;
 598 }