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