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/globals.h"
  24 #include "../librpc/gen_ndr/ndr_notify.h"
  25
  26 struct notify_change_request {
  27         struct notify_change_request *prev, *next;
  28         struct files_struct *fsp;       /* backpointer for cancel by mid */
  29         struct smb_request *req;
  30         uint32 filter;
  31         uint32 max_param;
  32         void (*reply_fn)(struct smb_request *req,
  33                          NTSTATUS error_code,
  34                          uint8_t *buf, size_t len);
  35         struct notify_mid_map *mid_map;
  36         void *backend_data;
  37 };
  38
  39 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  40
  41 /*
  42  * For NTCancel, we need to find the notify_change_request indexed by
  43  * mid. Separate list here.
  44  */
  45
  46 struct notify_mid_map {
  47         struct notify_mid_map *prev, *next;
  48         struct notify_change_request *req;
  49         uint64_t mid;
  50 };
  51
  52 static bool notify_change_record_identical(struct notify_change *c1,
  53                                         struct notify_change *c2)
  54 {
  55         /* Note this is deliberately case sensitive. */
  56         if (c1->action == c2->action &&
  57                         strcmp(c1->name, c2->name) == 0) {
  58                 return True;
  59         }
  60         return False;
  61 }
  62
  63 static bool notify_marshall_changes(int num_changes,
  64                                 uint32 max_offset,
  65                                 struct notify_change *changes,
  66                                 DATA_BLOB *final_blob)
  67 {
  68         int i;
  69
  70         if (num_changes == -1) {
  71                 return false;
  72         }
  73
  74         for (i=0; i<num_changes; i++) {
  75                 enum ndr_err_code ndr_err;
  76                 struct notify_change *c;
  77                 struct FILE_NOTIFY_INFORMATION m;
  78                 DATA_BLOB blob;
  79
  80                 /* Coalesce any identical records. */
  81                 while (i+1 < num_changes &&
  82                         notify_change_record_identical(&changes[i],
  83                                                 &changes[i+1])) {
  84                         i++;
  85                 }
  86
  87                 c = &changes[i];
  88
  89                 m.FileName1 = c->name;
  90                 m.FileNameLength = strlen_m(c->name)*2;
  91                 m.Action = c->action;
  92                 m.NextEntryOffset = (i == num_changes-1) ? 0 : ndr_size_FILE_NOTIFY_INFORMATION(&m, 0);
  93
  94                 /*
  95                  * Offset to next entry, only if there is one
  96                  */
  97
  98                 ndr_err = ndr_push_struct_blob(&blob, talloc_tos(), &m,
  99                         (ndr_push_flags_fn_t)ndr_push_FILE_NOTIFY_INFORMATION);
 100                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 101                         return false;
 102                 }
 103
 104                 if (DEBUGLEVEL >= 10) {
 105                         NDR_PRINT_DEBUG(FILE_NOTIFY_INFORMATION, &m);
 106                 }
 107
 108                 if (!data_blob_append(talloc_tos(), final_blob,
 109                                       blob.data, blob.length)) {
 110                         data_blob_free(&blob);
 111                         return false;
 112                 }
 113
 114                 data_blob_free(&blob);
 115
 116                 if (final_blob->length > max_offset) {
 117                         /* Too much data for client. */
 118                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 119                                    "marshall %d bytes\n", (int)max_offset,
 120                                    (int)final_blob->length));
 121                         return False;
 122                 }
 123         }
 124
 125         return True;
 126 }
 127
 128 /****************************************************************************
 129  Setup the common parts of the return packet and send it.
 130 *****************************************************************************/
 131
 132 void change_notify_reply(struct smb_request *req,
 133                          NTSTATUS error_code,
 134                          uint32_t max_param,
 135                          struct notify_change_buf *notify_buf,
 136                          void (*reply_fn)(struct smb_request *req,
 137                                           NTSTATUS error_code,
 138                                           uint8_t *buf, size_t len))
 139 {
 140         DATA_BLOB blob = data_blob_null;
 141
 142         if (!NT_STATUS_IS_OK(error_code)) {
 143                 reply_fn(req, error_code, NULL, 0);
 144                 return;
 145         }
 146
 147         if (max_param == 0 || notify_buf == NULL) {
 148                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 149                 return;
 150         }
 151
 152         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 153                                         notify_buf->changes, &blob)) {
 154                 /*
 155                  * We exceed what the client is willing to accept. Send
 156                  * nothing.
 157                  */
 158                 data_blob_free(&blob);
 159         }
 160
 161         reply_fn(req, NT_STATUS_OK, blob.data, blob.length);
 162
 163         data_blob_free(&blob);
 164
 165         TALLOC_FREE(notify_buf->changes);
 166         notify_buf->num_changes = 0;
 167 }
 168
 169 static void notify_callback(void *private_data, const struct notify_event *e)
 170 {
 171         files_struct *fsp = (files_struct *)private_data;
 172         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 173         notify_fsp(fsp, e->action, e->path);
 174 }
 175
 176 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 177                               bool recursive)
 178 {
 179         char *fullpath;
 180         struct notify_entry e;
 181         NTSTATUS status;
 182
 183         SMB_ASSERT(fsp->notify == NULL);
 184
 185         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 186                 DEBUG(0, ("talloc failed\n"));
 187                 return NT_STATUS_NO_MEMORY;
 188         }
 189
 190         /* Do notify operations on the base_name. */
 191         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 192                      fsp->fsp_name->base_name) == -1) {
 193                 DEBUG(0, ("asprintf failed\n"));
 194                 TALLOC_FREE(fsp->notify);
 195                 return NT_STATUS_NO_MEMORY;
 196         }
 197
 198         ZERO_STRUCT(e);
 199         e.path = fullpath;
 200         e.dir_fd = fsp->fh->fd;
 201         e.dir_id = fsp->file_id;
 202         e.filter = filter;
 203         e.subdir_filter = 0;
 204         if (recursive) {
 205                 e.subdir_filter = filter;
 206         }
 207
 208         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 209         SAFE_FREE(fullpath);
 210
 211         return status;
 212 }
 213
 214 NTSTATUS change_notify_add_request(struct smb_request *req,
 215                                 uint32 max_param,
 216                                 uint32 filter, bool recursive,
 217                                 struct files_struct *fsp,
 218                                 void (*reply_fn)(struct smb_request *req,
 219                                         NTSTATUS error_code,
 220                                         uint8_t *buf, size_t len))
 221 {
 222         struct notify_change_request *request = NULL;
 223         struct notify_mid_map *map = NULL;
 224         struct smbd_server_connection *sconn = req->sconn;
 225
 226         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 227                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 228
 229         if (!(request = talloc(NULL, struct notify_change_request))
 230             || !(map = talloc(request, struct notify_mid_map))) {
 231                 TALLOC_FREE(request);
 232                 return NT_STATUS_NO_MEMORY;
 233         }
 234
 235         request->mid_map = map;
 236         map->req = request;
 237
 238         request->req = talloc_move(request, &req);
 239         request->max_param = max_param;
 240         request->filter = filter;
 241         request->fsp = fsp;
 242         request->reply_fn = reply_fn;
 243         request->backend_data = NULL;
 244
 245         DLIST_ADD_END(fsp->notify->requests, request,
 246                       struct notify_change_request *);
 247
 248         map->mid = request->req->mid;
 249         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 250
 251         return NT_STATUS_OK;
 252 }
 253
 254 static void change_notify_remove_request(struct smbd_server_connection *sconn,
 255                                          struct notify_change_request *remove_req)
 256 {
 257         files_struct *fsp;
 258         struct notify_change_request *req;
 259
 260         /*
 261          * Paranoia checks, the fsp referenced must must have the request in
 262          * its list of pending requests
 263          */
 264
 265         fsp = remove_req->fsp;
 266         SMB_ASSERT(fsp->notify != NULL);
 267
 268         for (req = fsp->notify->requests; req; req = req->next) {
 269                 if (req == remove_req) {
 270                         break;
 271                 }
 272         }
 273
 274         if (req == NULL) {
 275                 smb_panic("notify_req not found in fsp's requests");
 276         }
 277
 278         DLIST_REMOVE(fsp->notify->requests, req);
 279         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 280         TALLOC_FREE(req);
 281 }
 282
 283 /****************************************************************************
 284  Delete entries by mid from the change notify pending queue. Always send reply.
 285 *****************************************************************************/
 286
 287 void remove_pending_change_notify_requests_by_mid(
 288         struct smbd_server_connection *sconn, uint64_t mid)
 289 {
 290         struct notify_mid_map *map;
 291
 292         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 293                 if (map->mid == mid) {
 294                         break;
 295                 }
 296         }
 297
 298         if (map == NULL) {
 299                 return;
 300         }
 301
 302         change_notify_reply(map->req->req,
 303                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 304         change_notify_remove_request(sconn, map->req);
 305 }
 306
 307 void smbd_notify_cancel_by_smbreq(const struct smb_request *smbreq)
 308 {
 309         struct smbd_server_connection *sconn = smbreq->sconn;
 310         struct notify_mid_map *map;
 311
 312         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 313                 if (map->req->req == smbreq) {
 314                         break;
 315                 }
 316         }
 317
 318         if (map == NULL) {
 319                 return;
 320         }
 321
 322         change_notify_reply(map->req->req,
 323                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 324         change_notify_remove_request(sconn, map->req);
 325 }
 326
 327 /****************************************************************************
 328  Delete entries by fnum from the change notify pending queue.
 329 *****************************************************************************/
 330
 331 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 332                                                   NTSTATUS status)
 333 {
 334         if (fsp->notify == NULL) {
 335                 return;
 336         }
 337
 338         while (fsp->notify->requests != NULL) {
 339                 change_notify_reply(fsp->notify->requests->req,
 340                                     status, 0, NULL,
 341                                     fsp->notify->requests->reply_fn);
 342                 change_notify_remove_request(fsp->conn->sconn,
 343                                              fsp->notify->requests);
 344         }
 345 }
 346
 347 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 348                   const char *path)
 349 {
 350         char *fullpath;
 351         char *parent;
 352         const char *name;
 353
 354         if (path[0] == '.' && path[1] == '/') {
 355                 path += 2;
 356         }
 357         if (parent_dirname(talloc_tos(), path, &parent, &name)) {
 358                 struct smb_filename smb_fname_parent;
 359
 360                 ZERO_STRUCT(smb_fname_parent);
 361                 smb_fname_parent.base_name = parent;
 362
 363                 if (SMB_VFS_STAT(conn, &smb_fname_parent) != -1) {
 364                         notify_onelevel(conn->notify_ctx, action, filter,
 365                             SMB_VFS_FILE_ID_CREATE(conn, &smb_fname_parent.st),
 366                             name);
 367                 }
 368         }
 369
 370         fullpath = talloc_asprintf(talloc_tos(), "%s/%s", conn->connectpath,
 371                                    path);
 372         if (fullpath == NULL) {
 373                 DEBUG(0, ("asprintf failed\n"));
 374                 return;
 375         }
 376         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 377         TALLOC_FREE(fullpath);
 378 }
 379
 380 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 381 {
 382         struct notify_change *change, *changes;
 383         char *tmp;
 384
 385         if (fsp->notify == NULL) {
 386                 /*
 387                  * Nobody is waiting, don't queue
 388                  */
 389                 return;
 390         }
 391
 392         /*
 393          * Someone has triggered a notify previously, queue the change for
 394          * later.
 395          */
 396
 397         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 398                 /*
 399                  * The real number depends on the client buf, just provide a
 400                  * guard against a DoS here.  If name == NULL the CN backend is
 401                  * alerting us to a problem.  Possibly dropped events.  Clear
 402                  * queued changes and send the catch-all response to the client
 403                  * if a request is pending.
 404                  */
 405                 TALLOC_FREE(fsp->notify->changes);
 406                 fsp->notify->num_changes = -1;
 407                 if (fsp->notify->requests != NULL) {
 408                         change_notify_reply(fsp->notify->requests->req,
 409                                             NT_STATUS_OK,
 410                                             fsp->notify->requests->max_param,
 411                                             fsp->notify,
 412                                             fsp->notify->requests->reply_fn);
 413                         change_notify_remove_request(fsp->conn->sconn,
 414                                                      fsp->notify->requests);
 415                 }
 416                 return;
 417         }
 418
 419         /* If we've exceeded the server side queue or received a NULL name
 420          * from the underlying CN implementation, don't queue up any more
 421          * requests until we can send a catch-all response to the client */
 422         if (fsp->notify->num_changes == -1) {
 423                 return;
 424         }
 425
 426         if (!(changes = TALLOC_REALLOC_ARRAY(
 427                       fsp->notify, fsp->notify->changes,
 428                       struct notify_change, fsp->notify->num_changes+1))) {
 429                 DEBUG(0, ("talloc_realloc failed\n"));
 430                 return;
 431         }
 432
 433         fsp->notify->changes = changes;
 434
 435         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 436
 437         if (!(tmp = talloc_strdup(changes, name))) {
 438                 DEBUG(0, ("talloc_strdup failed\n"));
 439                 return;
 440         }
 441
 442         string_replace(tmp, '/', '\\');
 443         change->name = tmp;
 444
 445         change->action = action;
 446         fsp->notify->num_changes += 1;
 447
 448         if (fsp->notify->requests == NULL) {
 449                 /*
 450                  * Nobody is waiting, so don't send anything. The ot
 451                  */
 452                 return;
 453         }
 454
 455         if (action == NOTIFY_ACTION_OLD_NAME) {
 456                 /*
 457                  * We have to send the two rename events in one reply. So hold
 458                  * the first part back.
 459                  */
 460                 return;
 461         }
 462
 463         /*
 464          * Someone is waiting for the change, trigger the reply immediately.
 465          *
 466          * TODO: do we have to walk the lists of requests pending?
 467          */
 468
 469         change_notify_reply(fsp->notify->requests->req,
 470                             NT_STATUS_OK,
 471                             fsp->notify->requests->max_param,
 472                             fsp->notify,
 473                             fsp->notify->requests->reply_fn);
 474
 475         change_notify_remove_request(fsp->conn->sconn, fsp->notify->requests);
 476 }
 477
 478 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 479 {
 480         char *result = NULL;
 481
 482         result = talloc_strdup(mem_ctx, "");
 483
 484         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 485                 result = talloc_asprintf_append(result, "FILE_NAME|");
 486         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 487                 result = talloc_asprintf_append(result, "DIR_NAME|");
 488         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 489                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 490         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 491                 result = talloc_asprintf_append(result, "SIZE|");
 492         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 493                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 494         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 495                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 496         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 497                 result = talloc_asprintf_append(result, "CREATION|");
 498         if (filter & FILE_NOTIFY_CHANGE_EA)
 499                 result = talloc_asprintf_append(result, "EA|");
 500         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 501                 result = talloc_asprintf_append(result, "SECURITY|");
 502         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 503                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 504         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 505                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 506         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 507                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 508
 509         if (result == NULL) return NULL;
 510         if (*result == '\0') return result;
 511
 512         result[strlen(result)-1] = '\0';
 513         return result;
 514 }
 515
 516 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 517                                                      TALLOC_CTX *mem_ctx,
 518                                                      struct event_context *ev)
 519 {
 520         struct sys_notify_context *ctx;
 521
 522         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 523                 DEBUG(0, ("talloc failed\n"));
 524                 return NULL;
 525         }
 526
 527         ctx->ev = ev;
 528         ctx->conn = conn;
 529         ctx->private_data = NULL;
 530         return ctx;
 531 }
 532
 533 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 534                           struct notify_entry *e,
 535                           void (*callback)(struct sys_notify_context *ctx,
 536                                            void *private_data,
 537                                            struct notify_event *ev),
 538                           void *private_data, void *handle)
 539 {
 540         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 541                                     handle);
 542 }
 543