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