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
  25 struct notify_change_request {
  26         struct notify_change_request *prev, *next;
  27         struct files_struct *fsp;       /* backpointer for cancel by mid */
  28         struct smb_request *req;
  29         uint32 filter;
  30         uint32 max_param;
  31         void (*reply_fn)(struct smb_request *req,
  32                          NTSTATUS error_code,
  33                          uint8_t *buf, size_t len);
  34         struct notify_mid_map *mid_map;
  35         void *backend_data;
  36 };
  37
  38 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  39
  40 /*
  41  * For NTCancel, we need to find the notify_change_request indexed by
  42  * mid. Separate list here.
  43  */
  44
  45 struct notify_mid_map {
  46         struct notify_mid_map *prev, *next;
  47         struct notify_change_request *req;
  48         uint16 mid;
  49 };
  50
  51 static bool notify_change_record_identical(struct notify_change *c1,
  52                                         struct notify_change *c2)
  53 {
  54         /* Note this is deliberately case sensitive. */
  55         if (c1->action == c2->action &&
  56                         strcmp(c1->name, c2->name) == 0) {
  57                 return True;
  58         }
  59         return False;
  60 }
  61
  62 static bool notify_marshall_changes(int num_changes,
  63                                 uint32 max_offset,
  64                                 struct notify_change *changes,
  65                                 prs_struct *ps)
  66 {
  67         int i;
  68         UNISTR uni_name;
  69
  70         if (num_changes == -1) {
  71                 return false;
  72         }
  73
  74         uni_name.buffer = NULL;
  75
  76         for (i=0; i<num_changes; i++) {
  77                 struct notify_change *c;
  78                 size_t namelen;
  79                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  80                                  * signed/unsigned issues */
  81
  82                 /* Coalesce any identical records. */
  83                 while (i+1 < num_changes &&
  84                         notify_change_record_identical(&changes[i],
  85                                                 &changes[i+1])) {
  86                         i++;
  87                 }
  88
  89                 c = &changes[i];
  90
  91                 if (!convert_string_talloc(talloc_tos(), CH_UNIX, CH_UTF16LE,
  92                         c->name, strlen(c->name)+1, &uni_name.buffer,
  93                         &namelen, True) || (uni_name.buffer == NULL)) {
  94                         goto fail;
  95                 }
  96
  97                 namelen -= 2;   /* Dump NULL termination */
  98
  99                 /*
 100                  * Offset to next entry, only if there is one
 101                  */
 102
 103                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
 104                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
 105
 106                 u32_tmp = c->action;
 107                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 108
 109                 u32_tmp = namelen;
 110                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 111
 112                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 113
 114                 /*
 115                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 116                  */
 117                 prs_set_offset(ps, prs_offset(ps)-2);
 118
 119                 TALLOC_FREE(uni_name.buffer);
 120
 121                 if (prs_offset(ps) > max_offset) {
 122                         /* Too much data for client. */
 123                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 124                                    "marshall %d bytes\n", (int)max_offset,
 125                                    (int)prs_offset(ps)));
 126                         return False;
 127                 }
 128         }
 129
 130         return True;
 131
 132  fail:
 133         TALLOC_FREE(uni_name.buffer);
 134         return False;
 135 }
 136
 137 /****************************************************************************
 138  Setup the common parts of the return packet and send it.
 139 *****************************************************************************/
 140
 141 void change_notify_reply(connection_struct *conn,
 142                          struct smb_request *req,
 143                          NTSTATUS error_code,
 144                          uint32_t max_param,
 145                          struct notify_change_buf *notify_buf,
 146                          void (*reply_fn)(struct smb_request *req,
 147                                 NTSTATUS error_code,
 148                                 uint8_t *buf, size_t len))
 149 {
 150         prs_struct ps;
 151
 152         if (!NT_STATUS_IS_OK(error_code)) {
 153                 reply_fn(req, error_code, NULL, 0);
 154                 return;
 155         }
 156
 157         if (max_param == 0 || notify_buf == NULL) {
 158                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 159                 return;
 160         }
 161
 162         prs_init_empty(&ps, NULL, MARSHALL);
 163
 164         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 165                                         notify_buf->changes, &ps)) {
 166                 /*
 167                  * We exceed what the client is willing to accept. Send
 168                  * nothing.
 169                  */
 170                 prs_mem_free(&ps);
 171                 prs_init_empty(&ps, NULL, MARSHALL);
 172         }
 173
 174         reply_fn(req, NT_STATUS_OK, (uint8_t *)prs_data_p(&ps), prs_offset(&ps));
 175
 176         prs_mem_free(&ps);
 177
 178         TALLOC_FREE(notify_buf->changes);
 179         notify_buf->num_changes = 0;
 180 }
 181
 182 static void notify_callback(void *private_data, const struct notify_event *e)
 183 {
 184         files_struct *fsp = (files_struct *)private_data;
 185         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 186         notify_fsp(fsp, e->action, e->path);
 187 }
 188
 189 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 190                               bool recursive)
 191 {
 192         char *fullpath;
 193         struct notify_entry e;
 194         NTSTATUS status;
 195
 196         SMB_ASSERT(fsp->notify == NULL);
 197
 198         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 199                 DEBUG(0, ("talloc failed\n"));
 200                 return NT_STATUS_NO_MEMORY;
 201         }
 202
 203         /* Do notify operations on the base_name. */
 204         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 205                      fsp->fsp_name->base_name) == -1) {
 206                 DEBUG(0, ("asprintf failed\n"));
 207                 TALLOC_FREE(fsp->notify);
 208                 return NT_STATUS_NO_MEMORY;
 209         }
 210
 211         ZERO_STRUCT(e);
 212         e.path = fullpath;
 213         e.dir_fd = fsp->fh->fd;
 214         e.dir_id = fsp->file_id;
 215         e.filter = filter;
 216         e.subdir_filter = 0;
 217         if (recursive) {
 218                 e.subdir_filter = filter;
 219         }
 220
 221         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 222         SAFE_FREE(fullpath);
 223
 224         return status;
 225 }
 226
 227 NTSTATUS change_notify_add_request(struct smb_request *req,
 228                                 uint32 max_param,
 229                                 uint32 filter, bool recursive,
 230                                 struct files_struct *fsp,
 231                                 void (*reply_fn)(struct smb_request *req,
 232                                         NTSTATUS error_code,
 233                                         uint8_t *buf, size_t len))
 234 {
 235         struct notify_change_request *request = NULL;
 236         struct notify_mid_map *map = NULL;
 237         struct smbd_server_connection *sconn = smbd_server_conn;
 238
 239         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 240                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 241
 242         if (!(request = talloc(NULL, struct notify_change_request))
 243             || !(map = talloc(request, struct notify_mid_map))) {
 244                 TALLOC_FREE(request);
 245                 return NT_STATUS_NO_MEMORY;
 246         }
 247
 248         request->mid_map = map;
 249         map->req = request;
 250
 251         request->req = talloc_move(request, &req);
 252         request->max_param = max_param;
 253         request->filter = filter;
 254         request->fsp = fsp;
 255         request->reply_fn = reply_fn;
 256         request->backend_data = NULL;
 257
 258         DLIST_ADD_END(fsp->notify->requests, request,
 259                       struct notify_change_request *);
 260
 261         map->mid = request->req->mid;
 262         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 263
 264         return NT_STATUS_OK;
 265 }
 266
 267 static void change_notify_remove_request(struct notify_change_request *remove_req)
 268 {
 269         files_struct *fsp;
 270         struct notify_change_request *req;
 271         struct smbd_server_connection *sconn = smbd_server_conn;
 272
 273         /*
 274          * Paranoia checks, the fsp referenced must must have the request in
 275          * its list of pending requests
 276          */
 277
 278         fsp = remove_req->fsp;
 279         SMB_ASSERT(fsp->notify != NULL);
 280
 281         for (req = fsp->notify->requests; req; req = req->next) {
 282                 if (req == remove_req) {
 283                         break;
 284                 }
 285         }
 286
 287         if (req == NULL) {
 288                 smb_panic("notify_req not found in fsp's requests");
 289         }
 290
 291         DLIST_REMOVE(fsp->notify->requests, req);
 292         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 293         TALLOC_FREE(req);
 294 }
 295
 296 /****************************************************************************
 297  Delete entries by mid from the change notify pending queue. Always send reply.
 298 *****************************************************************************/
 299
 300 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 301 {
 302         struct notify_mid_map *map;
 303         struct smbd_server_connection *sconn = smbd_server_conn;
 304
 305         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 306                 if (map->mid == mid) {
 307                         break;
 308                 }
 309         }
 310
 311         if (map == NULL) {
 312                 return;
 313         }
 314
 315         change_notify_reply(map->req->fsp->conn, map->req->req,
 316                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 317         change_notify_remove_request(map->req);
 318 }
 319
 320 void smbd_notify_cancel_by_smbreq(struct smbd_server_connection *sconn,
 321                                   const struct smb_request *smbreq)
 322 {
 323         struct notify_mid_map *map;
 324
 325         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 326                 if (map->req->req == smbreq) {
 327                         break;
 328                 }
 329         }
 330
 331         if (map == NULL) {
 332                 return;
 333         }
 334
 335         change_notify_reply(map->req->fsp->conn, map->req->req,
 336                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 337         change_notify_remove_request(map->req);
 338 }
 339
 340 /****************************************************************************
 341  Delete entries by fnum from the change notify pending queue.
 342 *****************************************************************************/
 343
 344 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 345                                                   NTSTATUS status)
 346 {
 347         if (fsp->notify == NULL) {
 348                 return;
 349         }
 350
 351         while (fsp->notify->requests != NULL) {
 352                 change_notify_reply(fsp->conn, fsp->notify->requests->req,
 353                                     status, 0, NULL,
 354                                     fsp->notify->requests->reply_fn);
 355                 change_notify_remove_request(fsp->notify->requests);
 356         }
 357 }
 358
 359 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 360                   const char *path)
 361 {
 362         char *fullpath;
 363         char *parent;
 364         const char *name;
 365
 366         if (path[0] == '.' && path[1] == '/') {
 367                 path += 2;
 368         }
 369         if (parent_dirname(talloc_tos(), path, &parent, &name)) {
 370                 struct smb_filename smb_fname_parent;
 371
 372                 ZERO_STRUCT(smb_fname_parent);
 373                 smb_fname_parent.base_name = parent;
 374
 375                 if (SMB_VFS_STAT(conn, &smb_fname_parent) != -1) {
 376                         notify_onelevel(conn->notify_ctx, action, filter,
 377                             SMB_VFS_FILE_ID_CREATE(conn, &smb_fname_parent.st),
 378                             name);
 379                 }
 380         }
 381
 382         fullpath = talloc_asprintf(talloc_tos(), "%s/%s", conn->connectpath,
 383                                    path);
 384         if (fullpath == NULL) {
 385                 DEBUG(0, ("asprintf failed\n"));
 386                 return;
 387         }
 388         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 389         TALLOC_FREE(fullpath);
 390 }
 391
 392 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 393 {
 394         struct notify_change *change, *changes;
 395         char *tmp;
 396
 397         if (fsp->notify == NULL) {
 398                 /*
 399                  * Nobody is waiting, don't queue
 400                  */
 401                 return;
 402         }
 403
 404         /*
 405          * Someone has triggered a notify previously, queue the change for
 406          * later.
 407          */
 408
 409         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 410                 /*
 411                  * The real number depends on the client buf, just provide a
 412                  * guard against a DoS here.  If name == NULL the CN backend is
 413                  * alerting us to a problem.  Possibly dropped events.  Clear
 414                  * queued changes and send the catch-all response to the client
 415                  * if a request is pending.
 416                  */
 417                 TALLOC_FREE(fsp->notify->changes);
 418                 fsp->notify->num_changes = -1;
 419                 if (fsp->notify->requests != NULL) {
 420                         change_notify_reply(fsp->conn,
 421                                             fsp->notify->requests->req,
 422                                             NT_STATUS_OK,
 423                                             fsp->notify->requests->max_param,
 424                                             fsp->notify,
 425                                             fsp->notify->requests->reply_fn);
 426                         change_notify_remove_request(fsp->notify->requests);
 427                 }
 428                 return;
 429         }
 430
 431         /* If we've exceeded the server side queue or received a NULL name
 432          * from the underlying CN implementation, don't queue up any more
 433          * requests until we can send a catch-all response to the client */
 434         if (fsp->notify->num_changes == -1) {
 435                 return;
 436         }
 437
 438         if (!(changes = TALLOC_REALLOC_ARRAY(
 439                       fsp->notify, fsp->notify->changes,
 440                       struct notify_change, fsp->notify->num_changes+1))) {
 441                 DEBUG(0, ("talloc_realloc failed\n"));
 442                 return;
 443         }
 444
 445         fsp->notify->changes = changes;
 446
 447         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 448
 449         if (!(tmp = talloc_strdup(changes, name))) {
 450                 DEBUG(0, ("talloc_strdup failed\n"));
 451                 return;
 452         }
 453
 454         string_replace(tmp, '/', '\\');
 455         change->name = tmp;
 456
 457         change->action = action;
 458         fsp->notify->num_changes += 1;
 459
 460         if (fsp->notify->requests == NULL) {
 461                 /*
 462                  * Nobody is waiting, so don't send anything. The ot
 463                  */
 464                 return;
 465         }
 466
 467         if (action == NOTIFY_ACTION_OLD_NAME) {
 468                 /*
 469                  * We have to send the two rename events in one reply. So hold
 470                  * the first part back.
 471                  */
 472                 return;
 473         }
 474
 475         /*
 476          * Someone is waiting for the change, trigger the reply immediately.
 477          *
 478          * TODO: do we have to walk the lists of requests pending?
 479          */
 480
 481         change_notify_reply(fsp->conn,
 482                             fsp->notify->requests->req,
 483                             NT_STATUS_OK,
 484                             fsp->notify->requests->max_param,
 485                             fsp->notify,
 486                             fsp->notify->requests->reply_fn);
 487
 488         change_notify_remove_request(fsp->notify->requests);
 489 }
 490
 491 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 492 {
 493         char *result = NULL;
 494
 495         result = talloc_strdup(mem_ctx, "");
 496
 497         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 498                 result = talloc_asprintf_append(result, "FILE_NAME|");
 499         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 500                 result = talloc_asprintf_append(result, "DIR_NAME|");
 501         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 502                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 503         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 504                 result = talloc_asprintf_append(result, "SIZE|");
 505         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 506                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 507         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 508                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 509         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 510                 result = talloc_asprintf_append(result, "CREATION|");
 511         if (filter & FILE_NOTIFY_CHANGE_EA)
 512                 result = talloc_asprintf_append(result, "EA|");
 513         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 514                 result = talloc_asprintf_append(result, "SECURITY|");
 515         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 516                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 517         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 518                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 519         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 520                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 521
 522         if (result == NULL) return NULL;
 523         if (*result == '\0') return result;
 524
 525         result[strlen(result)-1] = '\0';
 526         return result;
 527 }
 528
 529 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 530                                                      TALLOC_CTX *mem_ctx,
 531                                                      struct event_context *ev)
 532 {
 533         struct sys_notify_context *ctx;
 534
 535         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 536                 DEBUG(0, ("talloc failed\n"));
 537                 return NULL;
 538         }
 539
 540         ctx->ev = ev;
 541         ctx->conn = conn;
 542         ctx->private_data = NULL;
 543         return ctx;
 544 }
 545
 546 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 547                           struct notify_entry *e,
 548                           void (*callback)(struct sys_notify_context *ctx,
 549                                            void *private_data,
 550                                            struct notify_event *ev),
 551                           void *private_data, void *handle)
 552 {
 553         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 554                                     handle);
 555 }
 556