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
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 static struct cnotify_fns *cnotify;
  25 static struct notify_mid_map *notify_changes_by_mid;
  26
  27 /****************************************************************************
  28  This is the structure to queue to implement NT change
  29  notify. It consists of smb_size bytes stored from the
  30  transact command (to keep the mid, tid etc around).
  31  Plus the fid to examine and notify private data.
  32 *****************************************************************************/
  33
  34 struct change_notify {
  35         struct change_notify *next, *prev;
  36         files_struct *fsp;
  37         uint32 flags;
  38         uint32 max_param_count;
  39         char request_buf[smb_size];
  40         void *change_data;
  41 };
  42
  43 /*
  44  * For NTCancel, we need to find the notify_change_request indexed by
  45  * mid. Separate list here.
  46  */
  47
  48 struct notify_mid_map {
  49         struct notify_mid_map *prev, *next;
  50         struct notify_change_request *req;
  51         uint16 mid;
  52 };
  53
  54 static struct change_notify *change_notify_list;
  55
  56 static BOOL notify_marshall_changes(unsigned num_changes,
  57                                     struct notify_change *changes,
  58                                     prs_struct *ps)
  59 {
  60         int i;
  61         UNISTR uni_name;
  62
  63         for (i=0; i<num_changes; i++) {
  64                 struct notify_change *c = &changes[i];
  65                 size_t namelen;
  66                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  67                                  * signed/unsigned issues */
  68
  69                 namelen = convert_string_allocate(
  70                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  71                         &uni_name.buffer, True);
  72                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  73                         goto fail;
  74                 }
  75
  76                 namelen -= 2;   /* Dump NULL termination */
  77
  78                 /*
  79                  * Offset to next entry, only if there is one
  80                  */
  81
  82                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  83                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  84
  85                 u32_tmp = c->action;
  86                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
  87
  88                 u32_tmp = namelen;
  89                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
  90
  91                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
  92
  93                 /*
  94                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
  95                  */
  96                 prs_set_offset(ps, prs_offset(ps)-2);
  97
  98                 SAFE_FREE(uni_name.buffer);
  99         }
 100
 101         return True;
 102
 103  fail:
 104         SAFE_FREE(uni_name.buffer);
 105         return False;
 106 }
 107
 108 /****************************************************************************
 109  Setup the common parts of the return packet and send it.
 110 *****************************************************************************/
 111
 112 static void change_notify_reply_packet(const char *request_buf,
 113                                        NTSTATUS error_code)
 114 {
 115         char outbuf[smb_size+38];
 116
 117         memset(outbuf, '\0', sizeof(outbuf));
 118         construct_reply_common(request_buf, outbuf);
 119
 120         ERROR_NT(error_code);
 121
 122         /*
 123          * Seems NT needs a transact command with an error code
 124          * in it. This is a longer packet than a simple error.
 125          */
 126         set_message(outbuf,18,0,False);
 127
 128         show_msg(outbuf);
 129         if (!send_smb(smbd_server_fd(),outbuf))
 130                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 131                                     "failed.");
 132 }
 133
 134 void change_notify_reply(const char *request_buf, uint32 max_param_count,
 135                          unsigned num_changes, struct notify_change *changes)
 136 {
 137         char *outbuf = NULL;
 138         prs_struct ps;
 139         size_t buflen = smb_size+38+max_param_count;
 140
 141         if (!prs_init(&ps, 0, NULL, False)
 142             || !notify_marshall_changes(num_changes, changes, &ps)) {
 143                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 144                 goto done;
 145         }
 146
 147         if (prs_offset(&ps) > max_param_count) {
 148                 /*
 149                  * We exceed what the client is willing to accept. Send
 150                  * nothing.
 151                  */
 152                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 153                 goto done;
 154         }
 155
 156         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 157                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 158                 goto done;
 159         }
 160
 161         construct_reply_common(request_buf, outbuf);
 162
 163         if (send_nt_replies(outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 164                             prs_offset(&ps), NULL, 0) == -1) {
 165                 exit_server("change_notify_reply_packet: send_smb failed.");
 166         }
 167
 168  done:
 169         SAFE_FREE(outbuf);
 170         prs_mem_free(&ps);
 171 }
 172
 173 /****************************************************************************
 174  Remove an entry from the list and free it, also closing any
 175  directory handle if necessary.
 176 *****************************************************************************/
 177
 178 static void change_notify_remove(struct change_notify *cnbp)
 179 {
 180         cnotify->remove_notify(cnbp->change_data);
 181         DLIST_REMOVE(change_notify_list, cnbp);
 182         ZERO_STRUCTP(cnbp);
 183         SAFE_FREE(cnbp);
 184 }
 185
 186 NTSTATUS change_notify_add_request(const char *inbuf, uint32 max_param_count,
 187                                    uint32 filter, struct files_struct *fsp)
 188 {
 189         struct notify_change_request *request = NULL;
 190         struct notify_mid_map *map = NULL;
 191
 192         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 193             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 194                 SAFE_FREE(request);
 195                 return NT_STATUS_NO_MEMORY;
 196         }
 197
 198         request->mid_map = map;
 199         map->req = request;
 200
 201         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 202         request->max_param_count = max_param_count;
 203         request->filter = filter;
 204         request->fsp = fsp;
 205         DLIST_ADD_END(fsp->notify->requests, request,
 206                       struct notify_change_request *);
 207
 208         map->mid = SVAL(inbuf, smb_mid);
 209         DLIST_ADD(notify_changes_by_mid, map);
 210
 211         /* Push the MID of this packet on the signing queue. */
 212         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 213
 214         return NT_STATUS_OK;
 215 }
 216
 217 static void change_notify_remove_request(struct notify_change_request *remove_req)
 218 {
 219         files_struct *fsp;
 220         struct notify_change_request *req;
 221
 222         /*
 223          * Paranoia checks, the fsp referenced must must have the request in
 224          * its list of pending requests
 225          */
 226
 227         fsp = remove_req->fsp;
 228         SMB_ASSERT(fsp->notify != NULL);
 229
 230         for (req = fsp->notify->requests; req; req = req->next) {
 231                 if (req == remove_req) {
 232                         break;
 233                 }
 234         }
 235
 236         if (req == NULL) {
 237                 smb_panic("notify_req not found in fsp's requests\n");
 238         }
 239
 240         DLIST_REMOVE(fsp->notify->requests, req);
 241         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 242         SAFE_FREE(req->mid_map);
 243         SAFE_FREE(req);
 244 }
 245
 246 /****************************************************************************
 247  Delete entries by mid from the change notify pending queue. Always send reply.
 248 *****************************************************************************/
 249
 250 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 251 {
 252         struct notify_mid_map *map;
 253
 254         for (map = notify_changes_by_mid; map; map = map->next) {
 255                 if (map->mid == mid) {
 256                         break;
 257                 }
 258         }
 259
 260         if (map == NULL) {
 261                 return;
 262         }
 263
 264         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 265         change_notify_remove_request(map->req);
 266 }
 267
 268 /****************************************************************************
 269  Delete entries by fnum from the change notify pending queue.
 270 *****************************************************************************/
 271
 272 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 273                                                   NTSTATUS status)
 274 {
 275         if (fsp->notify == NULL) {
 276                 return;
 277         }
 278
 279         while (fsp->notify->requests != NULL) {
 280                 change_notify_reply_packet(
 281                         fsp->notify->requests->request_buf, status);
 282                 change_notify_remove_request(fsp->notify->requests);
 283         }
 284 }
 285
 286 /****************************************************************************
 287  Delete entries by filename and cnum from the change notify pending queue.
 288  Always send reply.
 289 *****************************************************************************/
 290
 291 void remove_pending_change_notify_requests_by_filename(files_struct *fsp, NTSTATUS status)
 292 {
 293         struct change_notify *cnbp, *next;
 294
 295         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 296                 next=cnbp->next;
 297                 /*
 298                  * We know it refers to the same directory if the connection number and
 299                  * the filename are identical.
 300                  */
 301                 if((cnbp->fsp->conn == fsp->conn) && strequal(cnbp->fsp->fsp_name,fsp->fsp_name)) {
 302                         change_notify_reply_packet(cnbp->request_buf, status);
 303                         change_notify_remove(cnbp);
 304                 }
 305         }
 306 }
 307
 308 /****************************************************************************
 309  Set the current change notify timeout to the lowest value across all service
 310  values.
 311 ****************************************************************************/
 312
 313 void set_change_notify_timeout(int val)
 314 {
 315         if (val > 0) {
 316                 cnotify->select_time = MIN(cnotify->select_time, val);
 317         }
 318 }
 319
 320 /****************************************************************************
 321  Longest time to sleep for before doing a change notify scan.
 322 ****************************************************************************/
 323
 324 int change_notify_timeout(void)
 325 {
 326         return cnotify->select_time;
 327 }
 328
 329 /****************************************************************************
 330  Process the change notify queue. Note that this is only called as root.
 331  Returns True if there are still outstanding change notify requests on the
 332  queue.
 333 *****************************************************************************/
 334
 335 BOOL process_pending_change_notify_queue(time_t t)
 336 {
 337         struct change_notify *cnbp, *next;
 338         uint16 vuid;
 339
 340         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 341                 next=cnbp->next;
 342
 343                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID : SVAL(cnbp->request_buf,smb_uid);
 344
 345                 if (cnbp->fsp->notify->num_changes != 0) {
 346                         DEBUG(10,("process_pending_change_notify_queue: %s "
 347                                   "has %d changes!\n", cnbp->fsp->fsp_name,
 348                                   cnbp->fsp->notify->num_changes));
 349                         change_notify_reply(cnbp->request_buf,
 350                                             cnbp->max_param_count,
 351                                             cnbp->fsp->notify->num_changes,
 352                                             cnbp->fsp->notify->changes);
 353                         change_notify_remove(cnbp);
 354                         continue;
 355                 }
 356
 357                 if (cnotify->check_notify(cnbp->fsp->conn, vuid,
 358                                           cnbp->fsp->fsp_name, cnbp->flags,
 359                                           cnbp->change_data, t)) {
 360                         DEBUG(10,("process_pending_change_notify_queue: dir "
 361                                   "%s changed !\n", cnbp->fsp->fsp_name ));
 362                         change_notify_reply(cnbp->request_buf,
 363                                             cnbp->max_param_count,
 364                                             cnbp->fsp->notify->num_changes,
 365                                             cnbp->fsp->notify->changes);
 366                         change_notify_remove(cnbp);
 367                 }
 368         }
 369
 370         return (change_notify_list != NULL);
 371 }
 372
 373 /****************************************************************************
 374  Now queue an entry on the notify change list.
 375  We only need to save smb_size bytes from this incoming packet
 376  as we will always by returning a 'read the directory yourself'
 377  error.
 378 ****************************************************************************/
 379
 380 BOOL change_notify_set(char *inbuf, files_struct *fsp, connection_struct *conn,
 381                        uint32 flags, uint32 max_param_count)
 382 {
 383         struct change_notify *cnbp;
 384
 385         if((cnbp = SMB_MALLOC_P(struct change_notify)) == NULL) {
 386                 DEBUG(0,("change_notify_set: malloc fail !\n" ));
 387                 return False;
 388         }
 389
 390         ZERO_STRUCTP(cnbp);
 391
 392         memcpy(cnbp->request_buf, inbuf, smb_size);
 393         cnbp->fsp = fsp;
 394         cnbp->flags = flags;
 395         cnbp->max_param_count = max_param_count;
 396         cnbp->change_data = cnotify->register_notify(conn, fsp->fsp_name,
 397                                                      flags);
 398
 399         if (!cnbp->change_data) {
 400                 SAFE_FREE(cnbp);
 401                 return False;
 402         }
 403
 404         DLIST_ADD(change_notify_list, cnbp);
 405
 406         /* Push the MID of this packet on the signing queue. */
 407         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 408
 409         return True;
 410 }
 411
 412 int change_notify_fd(void)
 413 {
 414         if (cnotify) {
 415                 return cnotify->notification_fd;
 416         }
 417
 418         return -1;
 419 }
 420
 421 /* notify message definition
 422
 423 Offset  Data                    length.
 424 0       SMB_DEV_T dev           8
 425 8       SMB_INO_T inode         8
 426 16      uint32 filter           4
 427 20      uint32 action           4
 428 24..    name
 429 */
 430
 431 #define MSG_NOTIFY_MESSAGE_SIZE 25 /* Includes at least the '\0' terminator */
 432
 433 struct notify_message {
 434         SMB_DEV_T dev;
 435         SMB_INO_T inode;
 436         uint32 filter;
 437         uint32 action;
 438         char *name;
 439 };
 440
 441 static DATA_BLOB notify_message_to_buf(const struct notify_message *msg)
 442 {
 443         DATA_BLOB result;
 444         size_t len;
 445
 446         len = strlen(msg->name);
 447
 448         result = data_blob(NULL, MSG_NOTIFY_MESSAGE_SIZE + len);
 449         if (!result.data) {
 450                 return result;
 451         }
 452
 453         SDEV_T_VAL(result.data, 0, msg->dev);
 454         SINO_T_VAL(result.data, 8, msg->inode);
 455         SIVAL(result.data, 16, msg->filter);
 456         SIVAL(result.data, 20, msg->action);
 457         memcpy(result.data+24, msg->name, len+1);
 458
 459         return result;
 460 }
 461
 462 static BOOL buf_to_notify_message(void *buf, size_t len,
 463                                   struct notify_message *msg)
 464 {
 465         if (len < MSG_NOTIFY_MESSAGE_SIZE) {
 466                 DEBUG(0, ("Got invalid notify message of len %d\n",
 467                           (int)len));
 468                 return False;
 469         }
 470
 471         msg->dev     = DEV_T_VAL(buf, 0);
 472         msg->inode   = INO_T_VAL(buf, 8);
 473         msg->filter  = IVAL(buf, 16);
 474         msg->action  = IVAL(buf, 20);
 475         msg->name    = ((char *)buf)+24;
 476         return True;
 477 }
 478
 479 void notify_action(connection_struct *conn, const char *parent,
 480                    const char *name, uint32 filter, uint32_t action)
 481 {
 482         struct share_mode_lock *lck;
 483         SMB_STRUCT_STAT sbuf;
 484         int i;
 485         struct notify_message msg;
 486         DATA_BLOB blob;
 487
 488         struct process_id *pids;
 489         int num_pids;
 490
 491         DEBUG(10, ("notify_action: parent=%s, name=%s, action=%u\n",
 492                    parent, name, (unsigned)action));
 493
 494         if (SMB_VFS_STAT(conn, parent, &sbuf) != 0) {
 495                 /*
 496                  * Not 100% critical, ignore failure
 497                  */
 498                 return;
 499         }
 500
 501         if (!(lck = get_share_mode_lock(NULL, sbuf.st_dev, sbuf.st_ino,
 502                                         NULL, NULL))) {
 503                 return;
 504         }
 505
 506         msg.dev = sbuf.st_dev;
 507         msg.inode = sbuf.st_ino;
 508         msg.filter = filter;
 509         msg.action = action;
 510         msg.name = CONST_DISCARD(char *, name);
 511
 512         blob = notify_message_to_buf(&msg);
 513         if (blob.data == NULL) {
 514                 DEBUG(0, ("notify_message_to_buf failed\n"));
 515                 return;
 516         }
 517
 518         pids = NULL;
 519         num_pids = 0;
 520
 521         become_root_uid_only();
 522
 523         for (i=0; i<lck->num_share_modes; i++) {
 524                 struct share_mode_entry *e = &lck->share_modes[i];
 525                 int j;
 526                 struct process_id *tmp;
 527
 528                 for (j=0; j<num_pids; j++) {
 529                         if (procid_equal(&e->pid, &pids[j])) {
 530                                 break;
 531                         }
 532                 }
 533
 534                 if (j < num_pids) {
 535                         /*
 536                          * Already sent to that process, skip it
 537                          */
 538                         continue;
 539                 }
 540
 541                 message_send_pid(lck->share_modes[i].pid, MSG_SMB_NOTIFY,
 542                                  blob.data, blob.length, True);
 543
 544                 if (!(tmp = TALLOC_REALLOC_ARRAY(lck, pids, struct process_id,
 545                                                  num_pids+1))) {
 546                         DEBUG(0, ("realloc failed\n"));
 547                         break;
 548                 }
 549                 pids = tmp;
 550                 pids[num_pids] = e->pid;
 551                 num_pids += 1;
 552         }
 553
 554         unbecome_root_uid_only();
 555
 556         data_blob_free(&blob);
 557         TALLOC_FREE(lck);
 558 }
 559
 560 void notify_fname(connection_struct *conn, const char *path,
 561                   uint32 filter, uint32 action)
 562 {
 563         char *parent;
 564         const char *name;
 565
 566         if (!parent_dirname_talloc(tmp_talloc_ctx(), path, &parent, &name)) {
 567                 return;
 568         }
 569
 570         notify_action(conn, parent, name, filter, action);
 571         TALLOC_FREE(parent);
 572 }
 573
 574 static void notify_fsp(files_struct *fsp, struct notify_message *msg)
 575 {
 576         struct notify_change *change, *changes;
 577
 578         if (fsp->notify == NULL) {
 579                 /*
 580                  * Nobody is waiting, don't queue
 581                  */
 582                 return;
 583         }
 584
 585         if ((fsp->notify->requests != NULL)
 586             && (fsp->notify->requests->filter & msg->filter)) {
 587                 /*
 588                  * Someone is waiting for the change, trigger the reply
 589                  * immediately.
 590                  *
 591                  * TODO: do we have to walk the lists of requests pending?
 592                  */
 593
 594                 struct notify_change_request *req = fsp->notify->requests;
 595                 struct notify_change onechange;
 596
 597                 onechange.action = msg->action;
 598                 onechange.name = msg->name;
 599
 600                 change_notify_reply(req->request_buf, req->max_param_count,
 601                                     1, &onechange);
 602                 change_notify_remove_request(req);
 603                 return;
 604         }
 605
 606         /*
 607          * Someone has triggered a notify previously, queue the change for
 608          * later. TODO: Limit the number of changes queued, test how filters
 609          * apply here. Do we have to store them?
 610          */
 611
 612         if (!(changes = TALLOC_REALLOC_ARRAY(
 613                       fsp->notify, fsp->notify->changes,
 614                       struct notify_change, fsp->notify->num_changes+1))) {
 615                 DEBUG(0, ("talloc_realloc failed\n"));
 616                 return;
 617         }
 618
 619         fsp->notify->changes = changes;
 620
 621         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 622
 623         if (!(change->name = talloc_strdup(changes, msg->name))) {
 624                 DEBUG(0, ("talloc_strdup failed\n"));
 625                 return;
 626         }
 627         change->action = msg->action;
 628         fsp->notify->num_changes += 1;
 629
 630         return;
 631 }
 632
 633 static void notify_message_callback(int msgtype, struct process_id pid,
 634                                     void *buf, size_t len)
 635 {
 636         struct notify_message msg;
 637         files_struct *fsp;
 638
 639         if (!buf_to_notify_message(buf, len, &msg)) {
 640                 return;
 641         }
 642
 643         DEBUG(10, ("Received notify_message for 0x%x/%.0f: %d\n",
 644                    (unsigned)msg.dev, (double)msg.inode, msg.action));
 645
 646         for(fsp = fsp_find_di_first(msg.dev, msg.inode); fsp;
 647             fsp = fsp_find_di_next(fsp)) {
 648                 notify_fsp(fsp, &msg);
 649         }
 650 }
 651
 652 /****************************************************************************
 653  Initialise the change notify subsystem.
 654 ****************************************************************************/
 655
 656 BOOL init_change_notify(void)
 657 {
 658         cnotify = NULL;
 659
 660 #if HAVE_KERNEL_CHANGE_NOTIFY
 661         if (cnotify == NULL && lp_kernel_change_notify())
 662                 cnotify = kernel_notify_init();
 663 #endif
 664 #if HAVE_FAM_CHANGE_NOTIFY
 665         if (cnotify == NULL && lp_fam_change_notify())
 666                 cnotify = fam_notify_init();
 667 #endif
 668         if (!cnotify) cnotify = hash_notify_init();
 669
 670         if (!cnotify) {
 671                 DEBUG(0,("Failed to init change notify system\n"));
 672                 return False;
 673         }
 674
 675         message_register(MSG_SMB_NOTIFY, notify_message_callback);
 676
 677         return True;
 678 }