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/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                                 prs_struct *ps)
  67 {
  68         int i;
  69         UNISTR uni_name;
  70
  71         if (num_changes == -1) {
  72                 return false;
  73         }
  74
  75         uni_name.buffer = NULL;
  76
  77         for (i=0; i<num_changes; i++) {
  78                 struct notify_change *c;
  79                 size_t namelen;
  80                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  81                                  * signed/unsigned issues */
  82
  83                 /* Coalesce any identical records. */
  84                 while (i+1 < num_changes &&
  85                         notify_change_record_identical(&changes[i],
  86                                                 &changes[i+1])) {
  87                         i++;
  88                 }
  89
  90                 c = &changes[i];
  91
  92                 if (!convert_string_talloc(talloc_tos(), CH_UNIX, CH_UTF16LE,
  93                         c->name, strlen(c->name)+1, &uni_name.buffer,
  94                         &namelen, True) || (uni_name.buffer == NULL)) {
  95                         goto fail;
  96                 }
  97
  98                 namelen -= 2;   /* Dump NULL termination */
  99
 100                 /*
 101                  * Offset to next entry, only if there is one
 102                  */
 103
 104                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
 105                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
 106
 107                 u32_tmp = c->action;
 108                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 109
 110                 u32_tmp = namelen;
 111                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 112
 113                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 114
 115                 /*
 116                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 117                  */
 118                 prs_set_offset(ps, prs_offset(ps)-2);
 119
 120                 TALLOC_FREE(uni_name.buffer);
 121
 122                 if (prs_offset(ps) > max_offset) {
 123                         /* Too much data for client. */
 124                         DEBUG(10, ("Client only wanted %d bytes, trying to "
 125                                    "marshall %d bytes\n", (int)max_offset,
 126                                    (int)prs_offset(ps)));
 127                         return False;
 128                 }
 129         }
 130
 131         return True;
 132
 133  fail:
 134         TALLOC_FREE(uni_name.buffer);
 135         return False;
 136 }
 137
 138 /****************************************************************************
 139  Setup the common parts of the return packet and send it.
 140 *****************************************************************************/
 141
 142 void change_notify_reply(connection_struct *conn,
 143                          struct smb_request *req,
 144                          NTSTATUS error_code,
 145                          uint32_t max_param,
 146                          struct notify_change_buf *notify_buf,
 147                          void (*reply_fn)(struct smb_request *req,
 148                                 NTSTATUS error_code,
 149                                 uint8_t *buf, size_t len))
 150 {
 151         prs_struct ps;
 152
 153         if (!NT_STATUS_IS_OK(error_code)) {
 154                 reply_fn(req, error_code, NULL, 0);
 155                 return;
 156         }
 157
 158         if (max_param == 0 || notify_buf == NULL) {
 159                 reply_fn(req, NT_STATUS_OK, NULL, 0);
 160                 return;
 161         }
 162
 163         prs_init_empty(&ps, NULL, MARSHALL);
 164
 165         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 166                                         notify_buf->changes, &ps)) {
 167                 /*
 168                  * We exceed what the client is willing to accept. Send
 169                  * nothing.
 170                  */
 171                 prs_mem_free(&ps);
 172                 prs_init_empty(&ps, NULL, MARSHALL);
 173         }
 174
 175         reply_fn(req, NT_STATUS_OK, (uint8_t *)prs_data_p(&ps), prs_offset(&ps));
 176
 177         prs_mem_free(&ps);
 178
 179         TALLOC_FREE(notify_buf->changes);
 180         notify_buf->num_changes = 0;
 181 }
 182
 183 static void notify_callback(void *private_data, const struct notify_event *e)
 184 {
 185         files_struct *fsp = (files_struct *)private_data;
 186         DEBUG(10, ("notify_callback called for %s\n", fsp_str_dbg(fsp)));
 187         notify_fsp(fsp, e->action, e->path);
 188 }
 189
 190 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 191                               bool recursive)
 192 {
 193         char *fullpath;
 194         struct notify_entry e;
 195         NTSTATUS status;
 196
 197         SMB_ASSERT(fsp->notify == NULL);
 198
 199         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 200                 DEBUG(0, ("talloc failed\n"));
 201                 return NT_STATUS_NO_MEMORY;
 202         }
 203
 204         /* Do notify operations on the base_name. */
 205         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 206                      fsp->fsp_name->base_name) == -1) {
 207                 DEBUG(0, ("asprintf failed\n"));
 208                 TALLOC_FREE(fsp->notify);
 209                 return NT_STATUS_NO_MEMORY;
 210         }
 211
 212         ZERO_STRUCT(e);
 213         e.path = fullpath;
 214         e.dir_fd = fsp->fh->fd;
 215         e.dir_id = fsp->file_id;
 216         e.filter = filter;
 217         e.subdir_filter = 0;
 218         if (recursive) {
 219                 e.subdir_filter = filter;
 220         }
 221
 222         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 223         SAFE_FREE(fullpath);
 224
 225         return status;
 226 }
 227
 228 NTSTATUS change_notify_add_request(struct smb_request *req,
 229                                 uint32 max_param,
 230                                 uint32 filter, bool recursive,
 231                                 struct files_struct *fsp,
 232                                 void (*reply_fn)(struct smb_request *req,
 233                                         NTSTATUS error_code,
 234                                         uint8_t *buf, size_t len))
 235 {
 236         struct notify_change_request *request = NULL;
 237         struct notify_mid_map *map = NULL;
 238         struct smbd_server_connection *sconn = smbd_server_conn;
 239
 240         DEBUG(10, ("change_notify_add_request: Adding request for %s: "
 241                    "max_param = %d\n", fsp_str_dbg(fsp), (int)max_param));
 242
 243         if (!(request = talloc(NULL, struct notify_change_request))
 244             || !(map = talloc(request, struct notify_mid_map))) {
 245                 TALLOC_FREE(request);
 246                 return NT_STATUS_NO_MEMORY;
 247         }
 248
 249         request->mid_map = map;
 250         map->req = request;
 251
 252         request->req = talloc_move(request, &req);
 253         request->max_param = max_param;
 254         request->filter = filter;
 255         request->fsp = fsp;
 256         request->reply_fn = reply_fn;
 257         request->backend_data = NULL;
 258
 259         DLIST_ADD_END(fsp->notify->requests, request,
 260                       struct notify_change_request *);
 261
 262         map->mid = request->req->mid;
 263         DLIST_ADD(sconn->smb1.notify_mid_maps, map);
 264
 265         return NT_STATUS_OK;
 266 }
 267
 268 static void change_notify_remove_request(struct notify_change_request *remove_req)
 269 {
 270         files_struct *fsp;
 271         struct notify_change_request *req;
 272         struct smbd_server_connection *sconn = smbd_server_conn;
 273
 274         /*
 275          * Paranoia checks, the fsp referenced must must have the request in
 276          * its list of pending requests
 277          */
 278
 279         fsp = remove_req->fsp;
 280         SMB_ASSERT(fsp->notify != NULL);
 281
 282         for (req = fsp->notify->requests; req; req = req->next) {
 283                 if (req == remove_req) {
 284                         break;
 285                 }
 286         }
 287
 288         if (req == NULL) {
 289                 smb_panic("notify_req not found in fsp's requests");
 290         }
 291
 292         DLIST_REMOVE(fsp->notify->requests, req);
 293         DLIST_REMOVE(sconn->smb1.notify_mid_maps, req->mid_map);
 294         TALLOC_FREE(req);
 295 }
 296
 297 /****************************************************************************
 298  Delete entries by mid from the change notify pending queue. Always send reply.
 299 *****************************************************************************/
 300
 301 void remove_pending_change_notify_requests_by_mid(uint64_t mid)
 302 {
 303         struct notify_mid_map *map;
 304         struct smbd_server_connection *sconn = smbd_server_conn;
 305
 306         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 307                 if (map->mid == mid) {
 308                         break;
 309                 }
 310         }
 311
 312         if (map == NULL) {
 313                 return;
 314         }
 315
 316         change_notify_reply(map->req->fsp->conn, map->req->req,
 317                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 318         change_notify_remove_request(map->req);
 319 }
 320
 321 void smbd_notify_cancel_by_smbreq(struct smbd_server_connection *sconn,
 322                                   const struct smb_request *smbreq)
 323 {
 324         struct notify_mid_map *map;
 325
 326         for (map = sconn->smb1.notify_mid_maps; map; map = map->next) {
 327                 if (map->req->req == smbreq) {
 328                         break;
 329                 }
 330         }
 331
 332         if (map == NULL) {
 333                 return;
 334         }
 335
 336         change_notify_reply(map->req->fsp->conn, map->req->req,
 337                             NT_STATUS_CANCELLED, 0, NULL, map->req->reply_fn);
 338         change_notify_remove_request(map->req);
 339 }
 340
 341 /****************************************************************************
 342  Delete entries by fnum from the change notify pending queue.
 343 *****************************************************************************/
 344
 345 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 346                                                   NTSTATUS status)
 347 {
 348         if (fsp->notify == NULL) {
 349                 return;
 350         }
 351
 352         while (fsp->notify->requests != NULL) {
 353                 change_notify_reply(fsp->conn, fsp->notify->requests->req,
 354                                     status, 0, NULL,
 355                                     fsp->notify->requests->reply_fn);
 356                 change_notify_remove_request(fsp->notify->requests);
 357         }
 358 }
 359
 360 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 361                   const char *path)
 362 {
 363         char *fullpath;
 364         char *parent;
 365         const char *name;
 366
 367         if (path[0] == '.' && path[1] == '/') {
 368                 path += 2;
 369         }
 370         if (parent_dirname(talloc_tos(), path, &parent, &name)) {
 371                 struct smb_filename smb_fname_parent;
 372
 373                 ZERO_STRUCT(smb_fname_parent);
 374                 smb_fname_parent.base_name = parent;
 375
 376                 if (SMB_VFS_STAT(conn, &smb_fname_parent) != -1) {
 377                         notify_onelevel(conn->notify_ctx, action, filter,
 378                             SMB_VFS_FILE_ID_CREATE(conn, &smb_fname_parent.st),
 379                             name);
 380                 }
 381         }
 382
 383         fullpath = talloc_asprintf(talloc_tos(), "%s/%s", conn->connectpath,
 384                                    path);
 385         if (fullpath == NULL) {
 386                 DEBUG(0, ("asprintf failed\n"));
 387                 return;
 388         }
 389         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 390         TALLOC_FREE(fullpath);
 391 }
 392
 393 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 394 {
 395         struct notify_change *change, *changes;
 396         char *tmp;
 397
 398         if (fsp->notify == NULL) {
 399                 /*
 400                  * Nobody is waiting, don't queue
 401                  */
 402                 return;
 403         }
 404
 405         /*
 406          * Someone has triggered a notify previously, queue the change for
 407          * later.
 408          */
 409
 410         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 411                 /*
 412                  * The real number depends on the client buf, just provide a
 413                  * guard against a DoS here.  If name == NULL the CN backend is
 414                  * alerting us to a problem.  Possibly dropped events.  Clear
 415                  * queued changes and send the catch-all response to the client
 416                  * if a request is pending.
 417                  */
 418                 TALLOC_FREE(fsp->notify->changes);
 419                 fsp->notify->num_changes = -1;
 420                 if (fsp->notify->requests != NULL) {
 421                         change_notify_reply(fsp->conn,
 422                                             fsp->notify->requests->req,
 423                                             NT_STATUS_OK,
 424                                             fsp->notify->requests->max_param,
 425                                             fsp->notify,
 426                                             fsp->notify->requests->reply_fn);
 427                         change_notify_remove_request(fsp->notify->requests);
 428                 }
 429                 return;
 430         }
 431
 432         /* If we've exceeded the server side queue or received a NULL name
 433          * from the underlying CN implementation, don't queue up any more
 434          * requests until we can send a catch-all response to the client */
 435         if (fsp->notify->num_changes == -1) {
 436                 return;
 437         }
 438
 439         if (!(changes = TALLOC_REALLOC_ARRAY(
 440                       fsp->notify, fsp->notify->changes,
 441                       struct notify_change, fsp->notify->num_changes+1))) {
 442                 DEBUG(0, ("talloc_realloc failed\n"));
 443                 return;
 444         }
 445
 446         fsp->notify->changes = changes;
 447
 448         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 449
 450         if (!(tmp = talloc_strdup(changes, name))) {
 451                 DEBUG(0, ("talloc_strdup failed\n"));
 452                 return;
 453         }
 454
 455         string_replace(tmp, '/', '\\');
 456         change->name = tmp;
 457
 458         change->action = action;
 459         fsp->notify->num_changes += 1;
 460
 461         if (fsp->notify->requests == NULL) {
 462                 /*
 463                  * Nobody is waiting, so don't send anything. The ot
 464                  */
 465                 return;
 466         }
 467
 468         if (action == NOTIFY_ACTION_OLD_NAME) {
 469                 /*
 470                  * We have to send the two rename events in one reply. So hold
 471                  * the first part back.
 472                  */
 473                 return;
 474         }
 475
 476         /*
 477          * Someone is waiting for the change, trigger the reply immediately.
 478          *
 479          * TODO: do we have to walk the lists of requests pending?
 480          */
 481
 482         change_notify_reply(fsp->conn,
 483                             fsp->notify->requests->req,
 484                             NT_STATUS_OK,
 485                             fsp->notify->requests->max_param,
 486                             fsp->notify,
 487                             fsp->notify->requests->reply_fn);
 488
 489         change_notify_remove_request(fsp->notify->requests);
 490 }
 491
 492 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 493 {
 494         char *result = NULL;
 495
 496         result = talloc_strdup(mem_ctx, "");
 497
 498         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 499                 result = talloc_asprintf_append(result, "FILE_NAME|");
 500         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 501                 result = talloc_asprintf_append(result, "DIR_NAME|");
 502         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 503                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 504         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 505                 result = talloc_asprintf_append(result, "SIZE|");
 506         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 507                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 508         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 509                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 510         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 511                 result = talloc_asprintf_append(result, "CREATION|");
 512         if (filter & FILE_NOTIFY_CHANGE_EA)
 513                 result = talloc_asprintf_append(result, "EA|");
 514         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 515                 result = talloc_asprintf_append(result, "SECURITY|");
 516         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 517                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 518         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 519                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 520         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 521                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 522
 523         if (result == NULL) return NULL;
 524         if (*result == '\0') return result;
 525
 526         result[strlen(result)-1] = '\0';
 527         return result;
 528 }
 529
 530 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 531                                                      TALLOC_CTX *mem_ctx,
 532                                                      struct event_context *ev)
 533 {
 534         struct sys_notify_context *ctx;
 535
 536         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 537                 DEBUG(0, ("talloc failed\n"));
 538                 return NULL;
 539         }
 540
 541         ctx->ev = ev;
 542         ctx->conn = conn;
 543         ctx->private_data = NULL;
 544         return ctx;
 545 }
 546
 547 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 548                           struct notify_entry *e,
 549                           void (*callback)(struct sys_notify_context *ctx,
 550                                            void *private_data,
 551                                            struct notify_event *ev),
 552                           void *private_data, void *handle)
 553 {
 554         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 555                                     handle);
 556 }
 557