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