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, uint32 action, const char *name);
  67
  68 bool change_notify_fsp_has_changes(struct files_struct *fsp)
  69 {
  70         if (fsp == NULL) {
  71                 return false;
  72         }
  73
  74         if (fsp->notify == NULL) {
  75                 return false;
  76         }
  77
  78         if (fsp->notify->num_changes == 0) {
  79                 return false;
  80         }
  81
  82         return true;
  83 }
  84
  85 /*
  86  * For NTCancel, we need to find the notify_change_request indexed by
  87  * mid. Separate list here.
  88  */
  89
  90 struct notify_mid_map {
  91         struct notify_mid_map *prev, *next;
  92         struct notify_change_request *req;
  93         uint64_t mid;
  94 };
  95
  96 static bool notify_change_record_identical(struct notify_change_event *c1,
  97                                            struct notify_change_event *c2)
  98 {
  99         /* Note this is deliberately case sensitive. */
 100         if (c1->action == c2->action &&
 101                         strcmp(c1->name, c2->name) == 0) {
 102                 return True;
 103         }
 104         return False;
 105 }
 106
 107 static bool notify_marshall_changes(int num_changes,
 108                                 uint32 max_offset,
 109                                 struct notify_change_event *changes,
 110                                 DATA_BLOB *final_blob)
 111 {
 112         int i;
 113
 114         if (num_changes == -1) {
 115                 return false;
 116         }
 117
 118         for (i=0; i<num_changes; i++) {
 119                 enum ndr_err_code ndr_err;
 120                 struct notify_change_event *c;
 121                 struct FILE_NOTIFY_INFORMATION m;
 122                 DATA_BLOB blob;
 123
 124                 /* Coalesce any identical records. */
 125                 while (i+1 < num_changes &&
 126                         notify_change_record_identical(&changes[i],
 127                                                 &changes[i+1])) {
 128                         i++;
 129                 }
 130
 131                 c = &changes[i];
 132
 133                 m.FileName1 = c->name;
 134                 m.FileNameLength = strlen_m(c->name)*2;
 135                 m.Action = c->action;
 136                 m.NextEntryOffset = (i == num_changes-1) ? 0 : ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
 137
 138                 /*
 139                  * Offset to next entry, only if there is one
 140                  */
 141
 142                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
 143                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 144                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 145                         return false;
 146                 }
 147
 148                 if (DEBUGLEVEL >= 10) {
 149                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 150                 }
 151
 152                 if (!data_blob_append(talloc_tos(), final_blob,
 153                                       blob.data, blob.length)) {
 154                         data_blob_free(&blob);
 155                         return false;
 156                 }
 157
 158                 data_blob_free(&blob);
 159
 160                 if (final_blob->length > max_offset) {
 161                         /* Too much data for client. */
 162                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 163                                    "marshall %d bytes\n", (int)max_offset,
 164                                    (int)final_blob->length));
 165                         return False;
 166                 }
 167         }
 168
 169         return True;
 170 }
 171
 172 /****************************************************************************
 173  Setup the common parts of the return packet and send it.
 174 *****************************************************************************/
 175
 176 void change_notify_reply(struct smb_request *req,
 177                          NTSTATUS error_code,
 178                          uint32_t max_param,
 179                          struct notify_change_buf *notify_buf,
 180                          void (*reply_fn)(struct smb_request *req,
 181                                           NTSTATUS error_code,
 182                                           uint8_t *buf, size_t len))
 183 {
 184         DATA_BLOB blob = data_blob_null;
 185
 186         if (!NT_STATUS_IS_OK(error_code)) {
 187                 reply_fn(req, error_code, NULL, 0);
 188                 return;
 189         }
 190
 191         if (max_param == 0 || notify_buf == NULL) {
 192                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 193                 return;
 194         }
 195
 196         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 197                                         notify_buf->changes, &blob)) {
 198                 /*
 199                  * We exceed what the client is willing to accept. Send
 200                  * nothing.
 201                  */
 202                 data_blob_free(&blob);
 203         }
 204
 205         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 206
 207         data_blob_free(&blob);
 208
 209         TALLOC_FREE(notify_buf->changes);
 210         notify_buf->num_changes = 0;
 211 }
 212
 213 static void notify_callback(void *private_data, const struct notify_event *e)
 214 {
 215         files_struct *fsp = (files_struct *)private_data;
 216         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 217         notify_fsp(fsp, e->action, e->path);
 218 }
 219
 220 static void sys_notify_callback(struct sys_notify_context *ctx,
 221                                 void *private_data,
 222                                 struct notify_event *e)
 223 {
 224         files_struct *fsp = (files_struct *)private_data;
 225         DEBUG(10, ("sys_notify_callback called for %s\n", fsp_str_dbg(fsp)));
 226         notify_fsp(fsp, e->action, e->path);
 227 }
 228
 229 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 230                               bool recursive)
 231 {
 232         char *fullpath;
 233         size_t len;
 234         uint32_t subdir_filter;
 235         NTSTATUS status = NT_STATUS_NOT_IMPLEMENTED;
 236
 237         if (fsp->notify != NULL) {
 238                 DEBUG(1, ("change_notify_create: fsp->notify != NULL, "
 239                           "fname = %s\n", fsp->fsp_name->base_name));
 240                 return NT_STATUS_INVALID_PARAMETER;
 241         }
 242
 243         if (!(fsp->notify = talloc_zero(NULL, struct notify_change_buf))) {
 244                 DEBUG(0, ("talloc failed\n"));
 245                 return NT_STATUS_NO_MEMORY;
 246         }
 247
 248         /* Do notify operations on the base_name. */
 249         fullpath = talloc_asprintf(
 250                 talloc_tos(), "%s/%s", fsp->conn->connectpath,
 251                 fsp->fsp_name->base_name);
 252         if (fullpath == NULL) {
 253                 DEBUG(0, ("talloc_asprintf failed\n"));
 254                 TALLOC_FREE(fsp->notify);
 255                 return NT_STATUS_NO_MEMORY;
 256         }
 257
 258         /*
 259          * Avoid /. at the end of the path name. notify can't deal with it.
 260          */
 261         len = strlen(fullpath);
 262         if (len > 1 && fullpath[len-1] == '.' && fullpath[len-2] == '/') {
 263                 fullpath[len-2] = '\0';
 264         }
 265
 266         subdir_filter = recursive ? filter : 0;
 267
 268         if (fsp->conn->sconn->sys_notify_ctx != NULL) {
 269                 void *sys_notify_handle = NULL;
 270
 271                 status = SMB_VFS_NOTIFY_WATCH(
 272                         fsp->conn, fsp->conn->sconn->sys_notify_ctx,
 273                         fullpath, &filter, &subdir_filter,
 274                         sys_notify_callback, fsp, &sys_notify_handle);
 275
 276                 if (NT_STATUS_IS_OK(status)) {
 277                         talloc_steal(fsp->notify, sys_notify_handle);
 278                 }
 279         }
 280
 281         if ((filter != 0) || (subdir_filter != 0)) {
 282                 status = notify_add(fsp->conn->sconn->notify_ctx,
 283                                     fullpath, filter, subdir_filter,
 284                                     notify_callback, fsp);
 285         }
 286         TALLOC_FREE(fullpath);
 287         return status;
 288 }
 289
 290 NTSTATUS change_notify_add_request(struct smb_request *req,
 291                                 uint32 max_param,
 292                                 uint32 filter, bool recursive,
 293                                 struct files_struct *fsp,
 294                                 void (*reply_fn)(struct smb_request *req,
 295                                         NTSTATUS error_code,
 296                                         uint8_t *buf, size_t len))
 297 {
 298         struct notify_change_request *request = NULL;
 299         struct notify_mid_map *map = NULL;
 300         struct smbd_server_connection *sconn = req->sconn;
 301
 302         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 303                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 304
 305         if (!(request = talloc(NULL, struct notify_change_request))
 306             || !(map = talloc(request, struct notify_mid_map))) {
 307                 TALLOC_FREE(request);
 308                 return NT_STATUS_NO_MEMORY;
 309         }
 310
 311         request->mid_map = map;
 312         map->req = request;
 313
 314         request->req = talloc_move(request, &req);
 315         request->max_param = max_param;
 316         request->filter = filter;
 317         request->fsp = fsp;
 318         request->reply_fn = reply_fn;
 319         request->backend_data = NULL;
 320
 321         DLIST_ADD_END(fsp->notify->requests, request,
 322                       struct notify_change_request *);
 323
 324         map->mid = request->req->mid;
 325         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 326
 327         return NT_STATUS_OK;
 328 }
 329
 330 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 331                                          struct notify_change_request *remove_req)
 332 {
 333         files_struct *fsp;
 334         struct notify_change_request *req;
 335
 336         /*
 337          * Paranoia checks, the fsp referenced must must have the request in
 338          * its list of pending requests
 339          */
 340
 341         fsp = remove_req->fsp;
 342         SMB_ASSERT(fsp->notify != NULL);
 343
 344         for (req = fsp->notify->requests; req; req = req->next) {
 345                 if (req == remove_req) {
 346                         break;
 347                 }
 348         }
 349
 350         if (req == NULL) {
 351                 smb_panic("notify_req not found in fsp's requests");
 352         }
 353
 354         DLIST_REMOVE(fsp->notify->requests, req);
 355         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 356         TALLOC_FREE(req);
 357 }
 358
 359 /****************************************************************************
 360  Delete entries by mid from the change notify pending queue. Always send reply.
 361 *****************************************************************************/
 362
 363 void remove_pending_change_notify_requests_by_mid(
 364         struct smbd_server_connection *sconn, uint64_t mid)
 365 {
 366         struct notify_mid_map *map;
 367
 368         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 369                 if (map->mid == mid) {
 370                         break;
 371                 }
 372         }
 373
 374         if (map == NULL) {
 375                 return;
 376         }
 377
 378         change_notify_reply(map->req->req,
 379                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 380         change_notify_remove_request(sconn, map->req);
 381 }
 382
 383 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 384 {
 385         struct smbd_server_connection *sconn = smbreq->sconn;
 386         struct notify_mid_map *map;
 387
 388         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 389                 if (map->req->req == smbreq) {
 390                         break;
 391                 }
 392         }
 393
 394         if (map == NULL) {
 395                 return;
 396         }
 397
 398         change_notify_reply(map->req->req,
 399                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 400         change_notify_remove_request(sconn, map->req);
 401 }
 402
 403 /****************************************************************************
 404  Delete entries by fnum from the change notify pending queue.
 405 *****************************************************************************/
 406
 407 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 408                                                   NTSTATUS status)
 409 {
 410         if (fsp->notify == NULL) {
 411                 return;
 412         }
 413
 414         while (fsp->notify->requests != NULL) {
 415                 change_notify_reply(fsp->notify->requests->req,
 416                                     status, 0, NULL,
 417                                     fsp->notify->requests->reply_fn);
 418                 change_notify_remove_request(fsp->conn->sconn,
 419                                              fsp->notify->requests);
 420         }
 421 }
 422
 423 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 424                   const char *path)
 425 {
 426         struct notify_context *notify_ctx = conn->sconn->notify_ctx;
 427         char *fullpath, *to_free;
 428         char tmpbuf[PATH_MAX];
 429         ssize_t len;
 430
 431         if (path[0] == '.' && path[1] == '/') {
 432                 path += 2;
 433         }
 434         len = full_path_tos(conn->connectpath, path, tmpbuf, sizeof(tmpbuf),
 435                             &fullpath, &to_free);
 436         if (len == -1) {
 437                 DEBUG(0, ("full_path_tos failed\n"));
 438                 return;
 439         }
 440         notify_trigger(notify_ctx, action, filter, fullpath);
 441         TALLOC_FREE(to_free);
 442 }
 443
 444 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 445 {
 446         struct notify_change_event *change, *changes;
 447         char *tmp;
 448
 449         if (fsp->notify == NULL) {
 450                 /*
 451                  * Nobody is waiting, don't queue
 452                  */
 453                 return;
 454         }
 455
 456         /*
 457          * Someone has triggered a notify previously, queue the change for
 458          * later.
 459          */
 460
 461         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 462                 /*
 463                  * The real number depends on the client buf, just provide a
 464                  * guard against a DoS here.  If name == NULL the CN backend is
 465                  * alerting us to a problem.  Possibly dropped events.  Clear
 466                  * queued changes and send the catch-all response to the client
 467                  * if a request is pending.
 468                  */
 469                 TALLOC_FREE(fsp->notify->changes);
 470                 fsp->notify->num_changes = -1;
 471                 if (fsp->notify->requests != NULL) {
 472                         change_notify_reply(fsp->notify->requests->req,
 473                                             NT_STATUS_OK,
 474                                             fsp->notify->requests->max_param,
 475                                             fsp->notify,
 476                                             fsp->notify->requests->reply_fn);
 477                         change_notify_remove_request(fsp->conn->sconn,
 478                                                      fsp->notify->requests);
 479                 }
 480                 return;
 481         }
 482
 483         /* If we've exceeded the server side queue or received a NULL name
 484          * from the underlying CN implementation, don't queue up any more
 485          * requests until we can send a catch-all response to the client */
 486         if (fsp->notify->num_changes == -1) {
 487                 return;
 488         }
 489
 490         if (!(changes = talloc_realloc(
 491                       fsp->notify, fsp->notify->changes,
 492                       struct notify_change_event,
 493                       fsp->notify->num_changes+1))) {
 494                 DEBUG(0, ("talloc_realloc failed\n"));
 495                 return;
 496         }
 497
 498         fsp->notify->changes = changes;
 499
 500         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 501
 502         if (!(tmp = talloc_strdup(changes, name))) {
 503                 DEBUG(0, ("talloc_strdup failed\n"));
 504                 return;
 505         }
 506
 507         string_replace(tmp, '/', '\\');
 508         change->name = tmp;
 509
 510         change->action = action;
 511         fsp->notify->num_changes += 1;
 512
 513         if (fsp->notify->requests == NULL) {
 514                 /*
 515                  * Nobody is waiting, so don't send anything. The ot
 516                  */
 517                 return;
 518         }
 519
 520         if (action == NOTIFY_ACTION_OLD_NAME) {
 521                 /*
 522                  * We have to send the two rename events in one reply. So hold
 523                  * the first part back.
 524                  */
 525                 return;
 526         }
 527
 528         /*
 529          * Someone is waiting for the change, trigger the reply immediately.
 530          *
 531          * TODO: do we have to walk the lists of requests pending?
 532          */
 533
 534         change_notify_reply(fsp->notify->requests->req,
 535                             NT_STATUS_OK,
 536                             fsp->notify->requests->max_param,
 537                             fsp->notify,
 538                             fsp->notify->requests->reply_fn);
 539
 540         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 541 }
 542
 543 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 544 {
 545         char *result = NULL;
 546
 547         result = talloc_strdup(mem_ctx, "");
 548
 549         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 550                 result = talloc_asprintf_append(result, "FILE_NAME|");
 551         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 552                 result = talloc_asprintf_append(result, "DIR_NAME|");
 553         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 554                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 555         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 556                 result = talloc_asprintf_append(result, "SIZE|");
 557         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 558                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 559         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 560                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 561         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 562                 result = talloc_asprintf_append(result, "CREATION|");
 563         if (filter & FILE_NOTIFY_CHANGE_EA)
 564                 result = talloc_asprintf_append(result, "EA|");
 565         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 566                 result = talloc_asprintf_append(result, "SECURITY|");
 567         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 568                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 569         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 570                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 571         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 572                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 573
 574         if (result == NULL) return NULL;
 575         if (*result == '\0') return result;
 576
 577         result[strlen(result)-1] = '\0';
 578         return result;
 579 }
 580
 581 struct sys_notify_context *sys_notify_context_create(TALLOC_CTX *mem_ctx,
 582                                                      struct tevent_context *ev)
 583 {
 584         struct sys_notify_context *ctx;
 585
 586         if (!(ctx = talloc(mem_ctx, struct sys_notify_context))) {
 587                 DEBUG(0, ("talloc failed\n"));
 588                 return NULL;
 589         }
 590
 591         ctx->ev = ev;
 592         ctx->private_data = NULL;
 593         return ctx;
 594 }