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
  24 struct notify_change_request {
  25         struct notify_change_request *prev, *next;
  26         struct files_struct *fsp;       /* backpointer for cancel by mid */
  27         uint8 request_buf[smb_size];
  28         uint32 filter;
  29         uint32 max_param;
  30         struct notify_mid_map *mid_map;
  31         void *backend_data;
  32 };
  33
  34 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  35
  36 static struct notify_mid_map *notify_changes_by_mid;
  37
  38 /*
  39  * For NTCancel, we need to find the notify_change_request indexed by
  40  * mid. Separate list here.
  41  */
  42
  43 struct notify_mid_map {
  44         struct notify_mid_map *prev, *next;
  45         struct notify_change_request *req;
  46         uint16 mid;
  47 };
  48
  49 static BOOL notify_change_record_identical(struct notify_change *c1,
  50                                         struct notify_change *c2)
  51 {
  52         /* Note this is deliberately case sensitive. */
  53         if (c1->action == c2->action &&
  54                         strcmp(c1->name, c2->name) == 0) {
  55                 return True;
  56         }
  57         return False;
  58 }
  59
  60 static BOOL notify_marshall_changes(int num_changes,
  61                                 uint32 max_offset,
  62                                 struct notify_change *changes,
  63                                 prs_struct *ps)
  64 {
  65         int i;
  66         UNISTR uni_name;
  67
  68         for (i=0; i<num_changes; i++) {
  69                 struct notify_change *c;
  70                 size_t namelen;
  71                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  72                                  * signed/unsigned issues */
  73
  74                 /* Coalesce any identical records. */
  75                 while (i+1 < num_changes &&
  76                         notify_change_record_identical(&changes[i],
  77                                                 &changes[i+1])) {
  78                         i++;
  79                 }
  80
  81                 c = &changes[i];
  82
  83                 namelen = convert_string_allocate(
  84                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  85                         &uni_name.buffer, True);
  86                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  87                         goto fail;
  88                 }
  89
  90                 namelen -= 2;   /* Dump NULL termination */
  91
  92                 /*
  93                  * Offset to next entry, only if there is one
  94                  */
  95
  96                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  97                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  98
  99                 u32_tmp = c->action;
 100                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 101
 102                 u32_tmp = namelen;
 103                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 104
 105                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 106
 107                 /*
 108                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 109                  */
 110                 prs_set_offset(ps, prs_offset(ps)-2);
 111
 112                 SAFE_FREE(uni_name.buffer);
 113
 114                 if (prs_offset(ps) > max_offset) {
 115                         /* Too much data for client. */
 116                         return False;
 117                 }
 118         }
 119
 120         return True;
 121
 122  fail:
 123         SAFE_FREE(uni_name.buffer);
 124         return False;
 125 }
 126
 127 /****************************************************************************
 128  Setup the common parts of the return packet and send it.
 129 *****************************************************************************/
 130
 131 static void change_notify_reply_packet(const uint8 *request_buf,
 132                                        NTSTATUS error_code)
 133 {
 134         char outbuf[smb_size+38];
 135
 136         memset(outbuf, '\0', sizeof(outbuf));
 137         construct_reply_common((char *)request_buf, outbuf);
 138
 139         ERROR_NT(error_code);
 140
 141         /*
 142          * Seems NT needs a transact command with an error code
 143          * in it. This is a longer packet than a simple error.
 144          */
 145         set_message(outbuf,18,0,False);
 146
 147         show_msg(outbuf);
 148         if (!send_smb(smbd_server_fd(),outbuf))
 149                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 150                                     "failed.");
 151 }
 152
 153 void change_notify_reply(const uint8 *request_buf, uint32 max_param,
 154                          struct notify_change_buf *notify_buf)
 155 {
 156         prs_struct ps;
 157         struct smb_request *req = NULL;
 158         uint8 tmp_request[smb_size];
 159
 160         if (notify_buf->num_changes == -1) {
 161                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 162                 notify_buf->num_changes = 0;
 163                 return;
 164         }
 165
 166         prs_init(&ps, 0, NULL, MARSHALL);
 167
 168         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 169                                         notify_buf->changes, &ps)) {
 170                 /*
 171                  * We exceed what the client is willing to accept. Send
 172                  * nothing.
 173                  */
 174                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 175                 goto done;
 176         }
 177
 178         if (!(req = talloc(talloc_tos(), struct smb_request))) {
 179                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 180                 goto done;
 181         }
 182
 183         memcpy(tmp_request, request_buf, smb_size);
 184
 185         /*
 186          * We're only interested in the header fields here
 187          */
 188
 189         smb_setlen((char *)tmp_request, smb_size);
 190         SCVAL(tmp_request, smb_wct, 0);
 191
 192         init_smb_request(req, tmp_request);
 193
 194         send_nt_replies(req, NT_STATUS_OK, prs_data_p(&ps),
 195                         prs_offset(&ps), NULL, 0);
 196
 197  done:
 198         TALLOC_FREE(req);
 199         prs_mem_free(&ps);
 200
 201         TALLOC_FREE(notify_buf->changes);
 202         notify_buf->num_changes = 0;
 203 }
 204
 205 static void notify_callback(void *private_data, const struct notify_event *e)
 206 {
 207         files_struct *fsp = (files_struct *)private_data;
 208         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 209         notify_fsp(fsp, e->action, e->path);
 210 }
 211
 212 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 213                               BOOL recursive)
 214 {
 215         char *fullpath;
 216         struct notify_entry e;
 217         NTSTATUS status;
 218
 219         SMB_ASSERT(fsp->notify == NULL);
 220
 221         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 222                 DEBUG(0, ("talloc failed\n"));
 223                 return NT_STATUS_NO_MEMORY;
 224         }
 225
 226         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 227                      fsp->fsp_name) == -1) {
 228                 DEBUG(0, ("asprintf failed\n"));
 229                 return NT_STATUS_NO_MEMORY;
 230         }
 231
 232         e.path = fullpath;
 233         e.filter = filter;
 234         e.subdir_filter = 0;
 235         if (recursive) {
 236                 e.subdir_filter = filter;
 237         }
 238
 239         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 240         SAFE_FREE(fullpath);
 241
 242         return status;
 243 }
 244
 245 NTSTATUS change_notify_add_request(const uint8 *inbuf, uint32 max_param,
 246                                    uint32 filter, BOOL recursive,
 247                                    struct files_struct *fsp)
 248 {
 249         struct notify_change_request *request = NULL;
 250         struct notify_mid_map *map = NULL;
 251
 252         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 253             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 254                 SAFE_FREE(request);
 255                 return NT_STATUS_NO_MEMORY;
 256         }
 257
 258         request->mid_map = map;
 259         map->req = request;
 260
 261         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 262         request->max_param = max_param;
 263         request->filter = filter;
 264         request->fsp = fsp;
 265         request->backend_data = NULL;
 266
 267         DLIST_ADD_END(fsp->notify->requests, request,
 268                       struct notify_change_request *);
 269
 270         map->mid = SVAL(inbuf, smb_mid);
 271         DLIST_ADD(notify_changes_by_mid, map);
 272
 273         /* Push the MID of this packet on the signing queue. */
 274         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 275
 276         return NT_STATUS_OK;
 277 }
 278
 279 static void change_notify_remove_request(struct notify_change_request *remove_req)
 280 {
 281         files_struct *fsp;
 282         struct notify_change_request *req;
 283
 284         /*
 285          * Paranoia checks, the fsp referenced must must have the request in
 286          * its list of pending requests
 287          */
 288
 289         fsp = remove_req->fsp;
 290         SMB_ASSERT(fsp->notify != NULL);
 291
 292         for (req = fsp->notify->requests; req; req = req->next) {
 293                 if (req == remove_req) {
 294                         break;
 295                 }
 296         }
 297
 298         if (req == NULL) {
 299                 smb_panic("notify_req not found in fsp's requests");
 300         }
 301
 302         DLIST_REMOVE(fsp->notify->requests, req);
 303         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 304         SAFE_FREE(req->mid_map);
 305         TALLOC_FREE(req->backend_data);
 306         SAFE_FREE(req);
 307 }
 308
 309 /****************************************************************************
 310  Delete entries by mid from the change notify pending queue. Always send reply.
 311 *****************************************************************************/
 312
 313 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 314 {
 315         struct notify_mid_map *map;
 316
 317         for (map = notify_changes_by_mid; map; map = map->next) {
 318                 if (map->mid == mid) {
 319                         break;
 320                 }
 321         }
 322
 323         if (map == NULL) {
 324                 return;
 325         }
 326
 327         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 328         change_notify_remove_request(map->req);
 329 }
 330
 331 /****************************************************************************
 332  Delete entries by fnum from the change notify pending queue.
 333 *****************************************************************************/
 334
 335 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 336                                                   NTSTATUS status)
 337 {
 338         if (fsp->notify == NULL) {
 339                 return;
 340         }
 341
 342         while (fsp->notify->requests != NULL) {
 343                 change_notify_reply_packet(
 344                         fsp->notify->requests->request_buf, status);
 345                 change_notify_remove_request(fsp->notify->requests);
 346         }
 347 }
 348
 349 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 350                   const char *path)
 351 {
 352         char *fullpath;
 353
 354         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 355                 DEBUG(0, ("asprintf failed\n"));
 356                 return;
 357         }
 358
 359         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 360         SAFE_FREE(fullpath);
 361 }
 362
 363 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 364 {
 365         struct notify_change *change, *changes;
 366         char *tmp;
 367
 368         if (fsp->notify == NULL) {
 369                 /*
 370                  * Nobody is waiting, don't queue
 371                  */
 372                 return;
 373         }
 374
 375         /*
 376          * Someone has triggered a notify previously, queue the change for
 377          * later.
 378          */
 379
 380         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 381                 /*
 382                  * The real number depends on the client buf, just provide a
 383                  * guard against a DoS here.
 384                  */
 385                 TALLOC_FREE(fsp->notify->changes);
 386                 fsp->notify->num_changes = -1;
 387                 return;
 388         }
 389
 390         if (fsp->notify->num_changes == -1) {
 391                 return;
 392         }
 393
 394         if (!(changes = TALLOC_REALLOC_ARRAY(
 395                       fsp->notify, fsp->notify->changes,
 396                       struct notify_change, fsp->notify->num_changes+1))) {
 397                 DEBUG(0, ("talloc_realloc failed\n"));
 398                 return;
 399         }
 400
 401         fsp->notify->changes = changes;
 402
 403         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 404
 405         if (!(tmp = talloc_strdup(changes, name))) {
 406                 DEBUG(0, ("talloc_strdup failed\n"));
 407                 return;
 408         }
 409
 410         string_replace(tmp, '/', '\\');
 411         change->name = tmp;
 412
 413         change->action = action;
 414         fsp->notify->num_changes += 1;
 415
 416         if (fsp->notify->requests == NULL) {
 417                 /*
 418                  * Nobody is waiting, so don't send anything. The ot
 419                  */
 420                 return;
 421         }
 422
 423         if (action == NOTIFY_ACTION_OLD_NAME) {
 424                 /*
 425                  * We have to send the two rename events in one reply. So hold
 426                  * the first part back.
 427                  */
 428                 return;
 429         }
 430
 431         /*
 432          * Someone is waiting for the change, trigger the reply immediately.
 433          *
 434          * TODO: do we have to walk the lists of requests pending?
 435          */
 436
 437         change_notify_reply(fsp->notify->requests->request_buf,
 438                             fsp->notify->requests->max_param,
 439                             fsp->notify);
 440
 441         change_notify_remove_request(fsp->notify->requests);
 442 }
 443
 444 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 445 {
 446         char *result = NULL;
 447
 448         result = talloc_strdup(mem_ctx, "");
 449
 450         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 451                 result = talloc_asprintf_append(result, "FILE_NAME|");
 452         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 453                 result = talloc_asprintf_append(result, "DIR_NAME|");
 454         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 455                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 456         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 457                 result = talloc_asprintf_append(result, "SIZE|");
 458         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 459                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 460         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 461                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 462         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 463                 result = talloc_asprintf_append(result, "CREATION|");
 464         if (filter & FILE_NOTIFY_CHANGE_EA)
 465                 result = talloc_asprintf_append(result, "EA|");
 466         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 467                 result = talloc_asprintf_append(result, "SECURITY|");
 468         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 469                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 470         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 471                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 472         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 473                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 474
 475         if (result == NULL) return NULL;
 476         if (*result == '\0') return result;
 477
 478         result[strlen(result)-1] = '\0';
 479         return result;
 480 }
 481
 482 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 483                                                      TALLOC_CTX *mem_ctx,
 484                                                      struct event_context *ev)
 485 {
 486         struct sys_notify_context *ctx;
 487
 488         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 489                 DEBUG(0, ("talloc failed\n"));
 490                 return NULL;
 491         }
 492
 493         ctx->ev = ev;
 494         ctx->conn = conn;
 495         ctx->private_data = NULL;
 496         return ctx;
 497 }
 498
 499 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 500                           struct notify_entry *e,
 501                           void (*callback)(struct sys_notify_context *ctx,
 502                                            void *private_data,
 503                                            struct notify_event *ev),
 504                           void *private_data, void *handle)
 505 {
 506         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 507                                     handle);
 508 }
 509