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