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
 223         if (req == NULL) {
 224                 smb_panic("notify_req not found in fsp's requests\n");
 225         }
 226
 227         DLIST_REMOVE(fsp->notify->requests, req);
 228         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 229         SAFE_FREE(req->mid_map);
 230         SAFE_FREE(req);
 231 }
 232
 233 /****************************************************************************
 234  Delete entries by mid from the change notify pending queue. Always send reply.
 235 *****************************************************************************/
 236
 237 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 238 {
 239         struct notify_mid_map *map;
 240
 241         for (map = notify_changes_by_mid; map; map = map->next) {
 242                 if (map->mid == mid) {
 243                         break;
 244                 }
 245         }
 246
 247         if (map == NULL) {
 248                 return;
 249         }
 250
 251         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 252         change_notify_remove_request(map->req);
 253 }
 254
 255 /****************************************************************************
 256  Delete entries by fnum from the change notify pending queue.
 257 *****************************************************************************/
 258
 259 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 260                                                   NTSTATUS status)
 261 {
 262         if (fsp->notify == NULL) {
 263                 return;
 264         }
 265
 266         while (fsp->notify->requests != NULL) {
 267                 change_notify_reply_packet(
 268                         fsp->notify->requests->request_buf, status);
 269                 change_notify_remove_request(fsp->notify->requests);
 270         }
 271 }
 272
 273 /****************************************************************************
 274  Delete entries by filename and cnum from the change notify pending queue.
 275  Always send reply.
 276 *****************************************************************************/
 277
 278 void remove_pending_change_notify_requests_by_filename(files_struct *fsp, NTSTATUS status)
 279 {
 280         struct change_notify *cnbp, *next;
 281
 282         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 283                 next=cnbp->next;
 284                 /*
 285                  * We know it refers to the same directory if the connection number and
 286                  * the filename are identical.
 287                  */
 288                 if((cnbp->fsp->conn == fsp->conn) && strequal(cnbp->fsp->fsp_name,fsp->fsp_name)) {
 289                         change_notify_reply_packet(cnbp->request_buf, status);
 290                         change_notify_remove(cnbp);
 291                 }
 292         }
 293 }
 294
 295 /****************************************************************************
 296  Set the current change notify timeout to the lowest value across all service
 297  values.
 298 ****************************************************************************/
 299
 300 void set_change_notify_timeout(int val)
 301 {
 302         if (val > 0) {
 303                 cnotify->select_time = MIN(cnotify->select_time, val);
 304         }
 305 }
 306
 307 /****************************************************************************
 308  Longest time to sleep for before doing a change notify scan.
 309 ****************************************************************************/
 310
 311 int change_notify_timeout(void)
 312 {
 313         return cnotify->select_time;
 314 }
 315
 316 /****************************************************************************
 317  Process the change notify queue. Note that this is only called as root.
 318  Returns True if there are still outstanding change notify requests on the
 319  queue.
 320 *****************************************************************************/
 321
 322 BOOL process_pending_change_notify_queue(time_t t)
 323 {
 324         struct change_notify *cnbp, *next;
 325         uint16 vuid;
 326
 327         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 328                 next=cnbp->next;
 329
 330                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID : SVAL(cnbp->request_buf,smb_uid);
 331
 332                 if (cnbp->fsp->notify->num_changes != 0) {
 333                         DEBUG(10,("process_pending_change_notify_queue: %s "
 334                                   "has %d changes!\n", cnbp->fsp->fsp_name,
 335                                   cnbp->fsp->notify->num_changes));
 336                         change_notify_reply(cnbp->request_buf,
 337                                             cnbp->max_param_count,
 338                                             cnbp->fsp->notify->num_changes,
 339                                             cnbp->fsp->notify->changes);
 340                         change_notify_remove(cnbp);
 341                         continue;
 342                 }
 343
 344                 if (cnotify->check_notify(cnbp->fsp->conn, vuid,
 345                                           cnbp->fsp->fsp_name, cnbp->flags,
 346                                           cnbp->change_data, t)) {
 347                         DEBUG(10,("process_pending_change_notify_queue: dir "
 348                                   "%s changed !\n", cnbp->fsp->fsp_name ));
 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                 }
 355         }
 356
 357         return (change_notify_list != NULL);
 358 }
 359
 360 /****************************************************************************
 361  Now queue an entry on the notify change list.
 362  We only need to save smb_size bytes from this incoming packet
 363  as we will always by returning a 'read the directory yourself'
 364  error.
 365 ****************************************************************************/
 366
 367 BOOL change_notify_set(char *inbuf, files_struct *fsp, connection_struct *conn,
 368                        uint32 flags, uint32 max_param_count)
 369 {
 370         struct change_notify *cnbp;
 371
 372         if((cnbp = SMB_MALLOC_P(struct change_notify)) == NULL) {
 373                 DEBUG(0,("change_notify_set: malloc fail !\n" ));
 374                 return False;
 375         }
 376
 377         ZERO_STRUCTP(cnbp);
 378
 379         memcpy(cnbp->request_buf, inbuf, smb_size);
 380         cnbp->fsp = fsp;
 381         cnbp->flags = flags;
 382         cnbp->max_param_count = max_param_count;
 383         cnbp->change_data = cnotify->register_notify(conn, fsp->fsp_name,
 384                                                      flags);
 385
 386         if (!cnbp->change_data) {
 387                 SAFE_FREE(cnbp);
 388                 return False;
 389         }
 390
 391         DLIST_ADD(change_notify_list, cnbp);
 392
 393         /* Push the MID of this packet on the signing queue. */
 394         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 395
 396         return True;
 397 }
 398
 399 int change_notify_fd(void)
 400 {
 401         if (cnotify) {
 402                 return cnotify->notification_fd;
 403         }
 404
 405         return -1;
 406 }
 407
 408 /* notify message definition
 409
 410 Offset  Data                    length.
 411 0       SMB_DEV_T dev           8
 412 8       SMB_INO_T inode         8
 413 16      uint32 filter           4
 414 20      uint32 action           4
 415 24..    name
 416 */
 417
 418 #define MSG_NOTIFY_MESSAGE_SIZE 25 /* Includes at least the '\0' terminator */
 419
 420 struct notify_message {
 421         SMB_DEV_T dev;
 422         SMB_INO_T inode;
 423         uint32 filter;
 424         uint32 action;
 425         char *name;
 426 };
 427
 428 static DATA_BLOB notify_message_to_buf(const struct notify_message *msg)
 429 {
 430         DATA_BLOB result;
 431         size_t len;
 432
 433         len = strlen(msg->name);
 434
 435         result = data_blob(NULL, MSG_NOTIFY_MESSAGE_SIZE + len);
 436         if (!result.data) {
 437                 return result;
 438         }
 439
 440         SDEV_T_VAL(result.data, 0, msg->dev);
 441         SINO_T_VAL(result.data, 8, msg->inode);
 442         SIVAL(result.data, 16, msg->filter);
 443         SIVAL(result.data, 20, msg->action);
 444         memcpy(result.data+24, msg->name, len+1);
 445
 446         return result;
 447 }
 448
 449 static BOOL buf_to_notify_message(void *buf, size_t len,
 450                                   struct notify_message *msg)
 451 {
 452         if (len < MSG_NOTIFY_MESSAGE_SIZE) {
 453                 DEBUG(0, ("Got invalid notify message of len %d\n",
 454                           (int)len));
 455                 return False;
 456         }
 457
 458         msg->dev     = DEV_T_VAL(buf, 0);
 459         msg->inode   = INO_T_VAL(buf, 8);
 460         msg->filter  = IVAL(buf, 16);
 461         msg->action  = IVAL(buf, 20);
 462         msg->name    = ((char *)buf)+24;
 463         return True;
 464 }
 465
 466 void notify_action(connection_struct *conn, const char *parent,
 467                    const char *name, uint32 filter, uint32_t action)
 468 {
 469         struct share_mode_lock *lck;
 470         SMB_STRUCT_STAT sbuf;
 471         int i;
 472         struct notify_message msg;
 473         DATA_BLOB blob;
 474
 475         struct process_id *pids;
 476         int num_pids;
 477
 478         DEBUG(10, ("notify_action: parent=%s, name=%s, action=%u\n",
 479                    parent, name, (unsigned)action));
 480
 481         if (SMB_VFS_STAT(conn, parent, &sbuf) != 0) {
 482                 /*
 483                  * Not 100% critical, ignore failure
 484                  */
 485                 return;
 486         }
 487
 488         if (!(lck = get_share_mode_lock(NULL, sbuf.st_dev, sbuf.st_ino,
 489                                         NULL, NULL))) {
 490                 return;
 491         }
 492
 493         msg.dev = sbuf.st_dev;
 494         msg.inode = sbuf.st_ino;
 495         msg.filter = filter;
 496         msg.action = action;
 497         msg.name = CONST_DISCARD(char *, name);
 498
 499         blob = notify_message_to_buf(&msg);
 500         if (blob.data == NULL) {
 501                 DEBUG(0, ("notify_message_to_buf failed\n"));
 502                 return;
 503         }
 504
 505         pids = NULL;
 506         num_pids = 0;
 507
 508         become_root_uid_only();
 509
 510         for (i=0; i<lck->num_share_modes; i++) {
 511                 struct share_mode_entry *e = &lck->share_modes[i];
 512                 int j;
 513                 struct process_id *tmp;
 514
 515                 for (j=0; j<num_pids; j++) {
 516                         if (procid_equal(&e->pid, &pids[j])) {
 517                                 break;
 518                         }
 519                 }
 520
 521                 if (j < num_pids) {
 522                         /*
 523                          * Already sent to that process, skip it
 524                          */
 525                         continue;
 526                 }
 527
 528                 message_send_pid(lck->share_modes[i].pid, MSG_SMB_NOTIFY,
 529                                  blob.data, blob.length, True);
 530
 531                 if (!(tmp = TALLOC_REALLOC_ARRAY(lck, pids, struct process_id,
 532                                                  num_pids+1))) {
 533                         DEBUG(0, ("realloc failed\n"));
 534                         break;
 535                 }
 536                 pids = tmp;
 537                 pids[num_pids] = e->pid;
 538                 num_pids += 1;
 539         }
 540
 541         unbecome_root_uid_only();
 542
 543         data_blob_free(&blob);
 544         TALLOC_FREE(lck);
 545 }
 546
 547 void notify_fname(connection_struct *conn, const char *path,
 548                   uint32 filter, uint32 action)
 549 {
 550         char *parent;
 551         const char *name;
 552
 553         if (!parent_dirname_talloc(tmp_talloc_ctx(), path, &parent, &name)) {
 554                 return;
 555         }
 556
 557         notify_action(conn, parent, name, filter, action);
 558         TALLOC_FREE(parent);
 559 }
 560
 561 static void notify_fsp(files_struct *fsp, struct notify_message *msg)
 562 {
 563         struct notify_change *change, *changes;
 564
 565         if (fsp->notify == NULL) {
 566                 /*
 567                  * Nobody is waiting, don't queue
 568                  */
 569                 return;
 570         }
 571
 572         if ((fsp->notify->requests != NULL)
 573             && (fsp->notify->requests->filter & msg->filter)) {
 574                 /*
 575                  * Someone is waiting for the change, trigger the reply
 576                  * immediately.
 577                  *
 578                  * TODO: do we have to walk the lists of requests pending?
 579                  */
 580
 581                 struct notify_change_request *req = fsp->notify->requests;
 582                 struct notify_change onechange;
 583
 584                 onechange.action = msg->action;
 585                 onechange.name = msg->name;
 586
 587                 change_notify_reply(req->request_buf, req->max_param_count,
 588                                     1, &onechange);
 589                 change_notify_remove_request(req);
 590                 return;
 591         }
 592
 593         /*
 594          * Someone has triggered a notify previously, queue the change for
 595          * later. TODO: Limit the number of changes queued, test how filters
 596          * apply here. Do we have to store them?
 597          */
 598
 599         if (!(changes = TALLOC_REALLOC_ARRAY(
 600                       fsp->notify, fsp->notify->changes,
 601                       struct notify_change, fsp->notify->num_changes+1))) {
 602                 DEBUG(0, ("talloc_realloc failed\n"));
 603                 return;
 604         }
 605
 606         fsp->notify->changes = changes;
 607
 608         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 609
 610         if (!(change->name = talloc_strdup(changes, msg->name))) {
 611                 DEBUG(0, ("talloc_strdup failed\n"));
 612                 return;
 613         }
 614         change->action = msg->action;
 615         fsp->notify->num_changes += 1;
 616
 617         return;
 618 }
 619
 620 static void notify_message_callback(int msgtype, struct process_id pid,
 621                                     void *buf, size_t len)
 622 {
 623         struct notify_message msg;
 624         files_struct *fsp;
 625
 626         if (!buf_to_notify_message(buf, len, &msg)) {
 627                 return;
 628         }
 629
 630         DEBUG(10, ("Received notify_message for 0x%x/%.0f: %d\n",
 631                    (unsigned)msg.dev, (double)msg.inode, msg.action));
 632
 633         for(fsp = fsp_find_di_first(msg.dev, msg.inode); fsp;
 634             fsp = fsp_find_di_next(fsp)) {
 635                 notify_fsp(fsp, &msg);
 636         }
 637 }
 638
 639 /****************************************************************************
 640  Initialise the change notify subsystem.
 641 ****************************************************************************/
 642
 643 BOOL init_change_notify(void)
 644 {
 645         cnotify = NULL;
 646
 647 #if HAVE_KERNEL_CHANGE_NOTIFY
 648         if (cnotify == NULL && lp_kernel_change_notify())
 649                 cnotify = kernel_notify_init();
 650 #endif
 651 #if HAVE_FAM_CHANGE_NOTIFY
 652         if (cnotify == NULL && lp_fam_change_notify())
 653                 cnotify = fam_notify_init();
 654 #endif
 655         if (!cnotify) cnotify = hash_notify_init();
 656
 657         if (!cnotify) {
 658                 DEBUG(0,("Failed to init change notify system\n"));
 659                 return False;
 660         }
 661
 662         message_register(MSG_SMB_NOTIFY, notify_message_callback);
 663
 664         return True;
 665 }