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->fsp_name));
 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         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 204                      fsp->fsp_name) == -1) {
 205                 DEBUG(0, ("asprintf failed\n"));
 206                 TALLOC_FREE(fsp->notify);
 207                 return NT_STATUS_NO_MEMORY;
 208         }
 209
 210         ZERO_STRUCT(e);
 211         e.path = fullpath;
 212         e.dir_fd = fsp->fh->fd;
 213         e.dir_id = fsp->file_id;
 214         e.filter = filter;
 215         e.subdir_filter = 0;
 216         if (recursive) {
 217                 e.subdir_filter = filter;
 218         }
 219
 220         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 221         SAFE_FREE(fullpath);
 222
 223         return status;
 224 }
 225
 226 NTSTATUS change_notify_add_request(struct smb_request *req,
 227                                 uint32 max_param,
 228                                 uint32 filter, bool recursive,
 229                                 struct files_struct *fsp,
 230                                 void (*reply_fn)(struct smb_request *req,
 231                                         NTSTATUS error_code,
 232                                         uint8_t *buf, size_t len))
 233 {
 234         struct notify_change_request *request = NULL;
 235         struct notify_mid_map *map = NULL;
 236         struct smbd_server_connection *sconn = smbd_server_conn;
 237
 238         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 239                    "max_param = %d\n", fsp->fsp_name, (int)max_param));
 240
 241         if (!(request = talloc(NULL, struct notify_change_request))
 242             || !(map = talloc(request, struct notify_mid_map))) {
 243                 TALLOC_FREE(request);
 244                 return NT_STATUS_NO_MEMORY;
 245         }
 246
 247         request->mid_map = map;
 248         map->req = request;
 249
 250         request->req = talloc_move(request, &req);
 251         request->max_param = max_param;
 252         request->filter = filter;
 253         request->fsp = fsp;
 254         request->reply_fn = reply_fn;
 255         request->backend_data = NULL;
 256
 257         DLIST_ADD_END(fsp->notify->requests, request,
 258                       struct notify_change_request *);
 259
 260         map->mid = request->req->mid;
 261         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 262
 263         return NT_STATUS_OK;
 264 }
 265
 266 static void change_notify_remove_request(struct notify_change_request *remove_req)
 267 {
 268         files_struct *fsp;
 269         struct notify_change_request *req;
 270         struct smbd_server_connection *sconn = smbd_server_conn;
 271
 272         /*
 273          * Paranoia checks, the fsp referenced must must have the request in
 274          * its list of pending requests
 275          */
 276
 277         fsp = remove_req->fsp;
 278         SMB_ASSERT(fsp->notify != NULL);
 279
 280         for (req = fsp->notify->requests; req; req = req->next) {
 281                 if (req == remove_req) {
 282                         break;
 283                 }
 284         }
 285
 286         if (req == NULL) {
 287                 smb_panic("notify_req not found in fsp's requests");
 288         }
 289
 290         DLIST_REMOVE(fsp->notify->requests, req);
 291         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 292         TALLOC_FREE(req);
 293 }
 294
 295 /****************************************************************************
 296  Delete entries by mid from the change notify pending queue. Always send reply.
 297 *****************************************************************************/
 298
 299 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 300 {
 301         struct notify_mid_map *map;
 302         struct smbd_server_connection *sconn = smbd_server_conn;
 303
 304         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 305                 if (map->mid == mid) {
 306                         break;
 307                 }
 308         }
 309
 310         if (map == NULL) {
 311                 return;
 312         }
 313
 314         change_notify_reply(map->req->fsp->conn, map->req->req,
 315                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 316         change_notify_remove_request(map->req);
 317 }
 318
 319 /****************************************************************************
 320  Delete entries by fnum from the change notify pending queue.
 321 *****************************************************************************/
 322
 323 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 324                                                   NTSTATUS status)
 325 {
 326         if (fsp->notify == NULL) {
 327                 return;
 328         }
 329
 330         while (fsp->notify->requests != NULL) {
 331                 change_notify_reply(fsp->conn, fsp->notify->requests->req,
 332                                     status, 0, NULL,
 333                                     fsp->notify->requests->reply_fn);
 334                 change_notify_remove_request(fsp->notify->requests);
 335         }
 336 }
 337
 338 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 339                   const char *path)
 340 {
 341         char *fullpath;
 342         char *parent;
 343         const char *name;
 344
 345         if (path[0] == '.' && path[1] == '/') {
 346                 path += 2;
 347         }
 348         if (parent_dirname(talloc_tos(), path, &parent, &name)) {
 349                 struct smb_filename *smb_fname_parent = NULL;
 350                 NTSTATUS status;
 351
 352                 status = create_synthetic_smb_fname(talloc_tos(), parent, NULL,
 353                                                     NULL, &smb_fname_parent);
 354                 if (!NT_STATUS_IS_OK(status)) {
 355                         return;
 356                 }
 357                 if (SMB_VFS_STAT(conn, smb_fname_parent) != -1) {
 358                         notify_onelevel(conn->notify_ctx, action, filter,
 359                             SMB_VFS_FILE_ID_CREATE(conn, &smb_fname_parent->st),
 360                             name);
 361                 }
 362                 TALLOC_FREE(smb_fname_parent);
 363         }
 364
 365         fullpath = talloc_asprintf(talloc_tos(), "%s/%s", conn->connectpath,
 366                                    path);
 367         if (fullpath == NULL) {
 368                 DEBUG(0, ("asprintf failed\n"));
 369                 return;
 370         }
 371         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 372         TALLOC_FREE(fullpath);
 373 }
 374
 375 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 376 {
 377         struct notify_change *change, *changes;
 378         char *tmp;
 379
 380         if (fsp->notify == NULL) {
 381                 /*
 382                  * Nobody is waiting, don't queue
 383                  */
 384                 return;
 385         }
 386
 387         /*
 388          * Someone has triggered a notify previously, queue the change for
 389          * later.
 390          */
 391
 392         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 393                 /*
 394                  * The real number depends on the client buf, just provide a
 395                  * guard against a DoS here.  If name == NULL the CN backend is
 396                  * alerting us to a problem.  Possibly dropped events.  Clear
 397                  * queued changes and send the catch-all response to the client
 398                  * if a request is pending.
 399                  */
 400                 TALLOC_FREE(fsp->notify->changes);
 401                 fsp->notify->num_changes = -1;
 402                 if (fsp->notify->requests != NULL) {
 403                         change_notify_reply(fsp->conn,
 404                                             fsp->notify->requests->req,
 405                                             NT_STATUS_OK,
 406                                             fsp->notify->requests->max_param,
 407                                             fsp->notify,
 408                                             fsp->notify->requests->reply_fn);
 409                         change_notify_remove_request(fsp->notify->requests);
 410                 }
 411                 return;
 412         }
 413
 414         /* If we've exceeded the server side queue or received a NULL name
 415          * from the underlying CN implementation, don't queue up any more
 416          * requests until we can send a catch-all response to the client */
 417         if (fsp->notify->num_changes == -1) {
 418                 return;
 419         }
 420
 421         if (!(changes = TALLOC_REALLOC_ARRAY(
 422                       fsp->notify, fsp->notify->changes,
 423                       struct notify_change, fsp->notify->num_changes+1))) {
 424                 DEBUG(0, ("talloc_realloc failed\n"));
 425                 return;
 426         }
 427
 428         fsp->notify->changes = changes;
 429
 430         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 431
 432         if (!(tmp = talloc_strdup(changes, name))) {
 433                 DEBUG(0, ("talloc_strdup failed\n"));
 434                 return;
 435         }
 436
 437         string_replace(tmp, '/', '\\');
 438         change->name = tmp;
 439
 440         change->action = action;
 441         fsp->notify->num_changes += 1;
 442
 443         if (fsp->notify->requests == NULL) {
 444                 /*
 445                  * Nobody is waiting, so don't send anything. The ot
 446                  */
 447                 return;
 448         }
 449
 450         if (action == NOTIFY_ACTION_OLD_NAME) {
 451                 /*
 452                  * We have to send the two rename events in one reply. So hold
 453                  * the first part back.
 454                  */
 455                 return;
 456         }
 457
 458         /*
 459          * Someone is waiting for the change, trigger the reply immediately.
 460          *
 461          * TODO: do we have to walk the lists of requests pending?
 462          */
 463
 464         change_notify_reply(fsp->conn,
 465                             fsp->notify->requests->req,
 466                             NT_STATUS_OK,
 467                             fsp->notify->requests->max_param,
 468                             fsp->notify,
 469                             fsp->notify->requests->reply_fn);
 470
 471         change_notify_remove_request(fsp->notify->requests);
 472 }
 473
 474 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 475 {
 476         char *result = NULL;
 477
 478         result = talloc_strdup(mem_ctx, "");
 479
 480         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 481                 result = talloc_asprintf_append(result, "FILE_NAME|");
 482         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 483                 result = talloc_asprintf_append(result, "DIR_NAME|");
 484         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 485                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 486         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 487                 result = talloc_asprintf_append(result, "SIZE|");
 488         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 489                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 490         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 491                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 492         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 493                 result = talloc_asprintf_append(result, "CREATION|");
 494         if (filter & FILE_NOTIFY_CHANGE_EA)
 495                 result = talloc_asprintf_append(result, "EA|");
 496         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 497                 result = talloc_asprintf_append(result, "SECURITY|");
 498         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 499                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 500         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 501                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 502         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 503                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 504
 505         if (result == NULL) return NULL;
 506         if (*result == '\0') return result;
 507
 508         result[strlen(result)-1] = '\0';
 509         return result;
 510 }
 511
 512 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 513                                                      TALLOC_CTX *mem_ctx,
 514                                                      struct event_context *ev)
 515 {
 516         struct sys_notify_context *ctx;
 517
 518         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 519                 DEBUG(0, ("talloc failed\n"));
 520                 return NULL;
 521         }
 522
 523         ctx->ev = ev;
 524         ctx->conn = conn;
 525         ctx->private_data = NULL;
 526         return ctx;
 527 }
 528
 529 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 530                           struct notify_entry *e,
 531                           void (*callback)(struct sys_notify_context *ctx,
 532                                            void *private_data,
 533                                            struct notify_event *ev),
 534                           void *private_data, void *handle)
 535 {
 536         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 537                                     handle);
 538 }
 539