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
  26 /****************************************************************************
  27  This is the structure to queue to implement NT change
  28  notify. It consists of smb_size bytes stored from the
  29  transact command (to keep the mid, tid etc around).
  30  Plus the fid to examine and notify private data.
  31 *****************************************************************************/
  32
  33 struct change_notify {
  34         struct change_notify *next, *prev;
  35         files_struct *fsp;
  36         uint32 flags;
  37         uint32 max_param_count;
  38         char request_buf[smb_size];
  39         void *change_data;
  40 };
  41
  42 static struct change_notify *change_notify_list;
  43
  44 static BOOL notify_marshall_changes(struct notify_changes *changes,
  45                                     prs_struct *ps)
  46 {
  47         int i;
  48         UNISTR uni_name;
  49
  50         for (i=0; i<changes->num_changes; i++) {
  51                 struct notify_change *c = &changes->changes[i];
  52                 size_t namelen;
  53                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  54                                  * signed/unsigned issues */
  55
  56                 namelen = convert_string_allocate(
  57                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  58                         &uni_name.buffer, True);
  59                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  60                         goto fail;
  61                 }
  62
  63                 namelen -= 2;   /* Dump NULL termination */
  64
  65                 /*
  66                  * Offset to next entry, only if there is one
  67                  */
  68
  69                 u32_tmp = (i == changes->num_changes-1) ? 0 : namelen + 12;
  70                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  71
  72                 u32_tmp = c->action;
  73                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
  74
  75                 u32_tmp = namelen;
  76                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
  77
  78                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
  79
  80                 /*
  81                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
  82                  */
  83                 prs_set_offset(ps, prs_offset(ps)-2);
  84
  85                 SAFE_FREE(uni_name.buffer);
  86         }
  87
  88         return True;
  89
  90  fail:
  91         SAFE_FREE(uni_name.buffer);
  92         return False;
  93 }
  94
  95 /****************************************************************************
  96  Setup the common parts of the return packet and send it.
  97 *****************************************************************************/
  98
  99 static void change_notify_reply_packet(const char *request_buf,
 100                                        NTSTATUS error_code)
 101 {
 102         char outbuf[smb_size+38];
 103
 104         memset(outbuf, '\0', sizeof(outbuf));
 105         construct_reply_common(request_buf, outbuf);
 106
 107         ERROR_NT(error_code);
 108
 109         /*
 110          * Seems NT needs a transact command with an error code
 111          * in it. This is a longer packet than a simple error.
 112          */
 113         set_message(outbuf,18,0,False);
 114
 115         show_msg(outbuf);
 116         if (!send_smb(smbd_server_fd(),outbuf))
 117                 exit_server_cleanly("change_notify_reply_packet: send_smb failed.");
 118 }
 119
 120 void change_notify_reply(const char *request_buf, uint32 max_param_count,
 121                          files_struct *fsp)
 122 {
 123         char *outbuf = NULL;
 124         prs_struct ps;
 125         size_t buflen = smb_size+38+max_param_count;
 126
 127         if (!prs_init(&ps, 0, NULL, False)
 128             || !notify_marshall_changes(fsp->notify, &ps)) {
 129                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 130                 goto done;
 131         }
 132
 133         if (prs_offset(&ps) > max_param_count) {
 134                 /*
 135                  * We exceed what the client is willing to accept. Send
 136                  * nothing.
 137                  */
 138                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 139                 goto done;
 140         }
 141
 142         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 143                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 144                 goto done;
 145         }
 146
 147         construct_reply_common(request_buf, outbuf);
 148
 149         if (send_nt_replies(outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 150                             prs_offset(&ps), NULL, 0) == -1) {
 151                 exit_server("change_notify_reply_packet: send_smb failed.");
 152         }
 153
 154  done:
 155         SAFE_FREE(outbuf);
 156         prs_mem_free(&ps);
 157         fsp->notify->num_changes = 0;
 158         TALLOC_FREE(fsp->notify->changes);
 159 }
 160
 161 /****************************************************************************
 162  Remove an entry from the list and free it, also closing any
 163  directory handle if necessary.
 164 *****************************************************************************/
 165
 166 static void change_notify_remove(struct change_notify *cnbp)
 167 {
 168         cnotify->remove_notify(cnbp->change_data);
 169         DLIST_REMOVE(change_notify_list, cnbp);
 170         ZERO_STRUCTP(cnbp);
 171         SAFE_FREE(cnbp);
 172 }
 173
 174 /****************************************************************************
 175  Delete entries by fnum from the change notify pending queue.
 176 *****************************************************************************/
 177
 178 void remove_pending_change_notify_requests_by_fid(files_struct *fsp, NTSTATUS status)
 179 {
 180         struct change_notify *cnbp, *next;
 181
 182         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 183                 next=cnbp->next;
 184                 if (cnbp->fsp->fnum == fsp->fnum) {
 185                         change_notify_reply_packet(cnbp->request_buf, status);
 186                         change_notify_remove(cnbp);
 187                 }
 188         }
 189 }
 190
 191 /****************************************************************************
 192  Delete entries by mid from the change notify pending queue. Always send reply.
 193 *****************************************************************************/
 194
 195 void remove_pending_change_notify_requests_by_mid(int mid)
 196 {
 197         struct change_notify *cnbp, *next;
 198
 199         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 200                 next=cnbp->next;
 201                 if(SVAL(cnbp->request_buf,smb_mid) == mid) {
 202                         change_notify_reply_packet(cnbp->request_buf,
 203                                                    NT_STATUS_CANCELLED);
 204                         change_notify_remove(cnbp);
 205                 }
 206         }
 207 }
 208
 209 /****************************************************************************
 210  Delete entries by filename and cnum from the change notify pending queue.
 211  Always send reply.
 212 *****************************************************************************/
 213
 214 void remove_pending_change_notify_requests_by_filename(files_struct *fsp, NTSTATUS status)
 215 {
 216         struct change_notify *cnbp, *next;
 217
 218         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 219                 next=cnbp->next;
 220                 /*
 221                  * We know it refers to the same directory if the connection number and
 222                  * the filename are identical.
 223                  */
 224                 if((cnbp->fsp->conn == fsp->conn) && strequal(cnbp->fsp->fsp_name,fsp->fsp_name)) {
 225                         change_notify_reply_packet(cnbp->request_buf, status);
 226                         change_notify_remove(cnbp);
 227                 }
 228         }
 229 }
 230
 231 /****************************************************************************
 232  Set the current change notify timeout to the lowest value across all service
 233  values.
 234 ****************************************************************************/
 235
 236 void set_change_notify_timeout(int val)
 237 {
 238         if (val > 0) {
 239                 cnotify->select_time = MIN(cnotify->select_time, val);
 240         }
 241 }
 242
 243 /****************************************************************************
 244  Longest time to sleep for before doing a change notify scan.
 245 ****************************************************************************/
 246
 247 int change_notify_timeout(void)
 248 {
 249         return cnotify->select_time;
 250 }
 251
 252 /****************************************************************************
 253  Process the change notify queue. Note that this is only called as root.
 254  Returns True if there are still outstanding change notify requests on the
 255  queue.
 256 *****************************************************************************/
 257
 258 BOOL process_pending_change_notify_queue(time_t t)
 259 {
 260         struct change_notify *cnbp, *next;
 261         uint16 vuid;
 262
 263         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 264                 next=cnbp->next;
 265
 266                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID : SVAL(cnbp->request_buf,smb_uid);
 267
 268                 if (cnbp->fsp->notify->num_changes != 0) {
 269                         DEBUG(10,("process_pending_change_notify_queue: %s "
 270                                   "has %d changes!\n", cnbp->fsp->fsp_name,
 271                                   cnbp->fsp->notify->num_changes));
 272                         change_notify_reply(cnbp->request_buf,
 273                                             cnbp->max_param_count,
 274                                             cnbp->fsp);
 275                         change_notify_remove(cnbp);
 276                         continue;
 277                 }
 278
 279                 if (cnotify->check_notify(cnbp->fsp->conn, vuid,
 280                                           cnbp->fsp->fsp_name, cnbp->flags,
 281                                           cnbp->change_data, t)) {
 282                         DEBUG(10,("process_pending_change_notify_queue: dir "
 283                                   "%s changed !\n", cnbp->fsp->fsp_name ));
 284                         change_notify_reply(cnbp->request_buf,
 285                                             cnbp->max_param_count,
 286                                             cnbp->fsp);
 287                         change_notify_remove(cnbp);
 288                 }
 289         }
 290
 291         return (change_notify_list != NULL);
 292 }
 293
 294 /****************************************************************************
 295  Now queue an entry on the notify change list.
 296  We only need to save smb_size bytes from this incoming packet
 297  as we will always by returning a 'read the directory yourself'
 298  error.
 299 ****************************************************************************/
 300
 301 BOOL change_notify_set(char *inbuf, files_struct *fsp, connection_struct *conn,
 302                        uint32 flags, uint32 max_param_count)
 303 {
 304         struct change_notify *cnbp;
 305
 306         if((cnbp = SMB_MALLOC_P(struct change_notify)) == NULL) {
 307                 DEBUG(0,("change_notify_set: malloc fail !\n" ));
 308                 return False;
 309         }
 310
 311         ZERO_STRUCTP(cnbp);
 312
 313         memcpy(cnbp->request_buf, inbuf, smb_size);
 314         cnbp->fsp = fsp;
 315         cnbp->flags = flags;
 316         cnbp->max_param_count = max_param_count;
 317         cnbp->change_data = cnotify->register_notify(conn, fsp->fsp_name,
 318                                                      flags);
 319
 320         if (!cnbp->change_data) {
 321                 SAFE_FREE(cnbp);
 322                 return False;
 323         }
 324
 325         DLIST_ADD(change_notify_list, cnbp);
 326
 327         /* Push the MID of this packet on the signing queue. */
 328         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 329
 330         return True;
 331 }
 332
 333 int change_notify_fd(void)
 334 {
 335         if (cnotify) {
 336                 return cnotify->notification_fd;
 337         }
 338
 339         return -1;
 340 }
 341
 342 /* notify message definition
 343
 344 Offset  Data                    length.
 345 0       SMB_DEV_T dev           8
 346 8       SMB_INO_T inode         8
 347 16      uint32 action           4
 348 20..    name
 349 */
 350
 351 #define MSG_NOTIFY_MESSAGE_SIZE 21 /* Includes at least the '\0' terminator */
 352
 353 struct notify_message {
 354         SMB_DEV_T dev;
 355         SMB_INO_T inode;
 356         uint32_t action;
 357         char *name;
 358 };
 359
 360 static DATA_BLOB notify_message_to_buf(const struct notify_message *msg)
 361 {
 362         DATA_BLOB result;
 363         size_t len;
 364
 365         len = strlen(msg->name);
 366
 367         result = data_blob(NULL, MSG_NOTIFY_MESSAGE_SIZE + len);
 368         if (!result.data) {
 369                 return result;
 370         }
 371
 372         SDEV_T_VAL(result.data, 0, msg->dev);
 373         SINO_T_VAL(result.data, 8, msg->inode);
 374         SIVAL(result.data, 16, msg->action);
 375         memcpy(result.data+20, msg->name, len+1);
 376
 377         return result;
 378 }
 379
 380 static BOOL buf_to_notify_message(void *buf, size_t len,
 381                                   struct notify_message *msg)
 382 {
 383         if (len < MSG_NOTIFY_MESSAGE_SIZE) {
 384                 DEBUG(0, ("Got invalid notify message of len %d\n", len));
 385                 return False;
 386         }
 387
 388         msg->dev     = DEV_T_VAL(buf, 0);
 389         msg->inode   = INO_T_VAL(buf, 8);
 390         msg->action  = IVAL(buf, 16);
 391         msg->name    = ((char *)buf)+20;
 392         return True;
 393 }
 394
 395 void notify_action(connection_struct *conn, const char *parent,
 396                    const char *name, uint32_t action)
 397 {
 398         struct share_mode_lock *lck;
 399         SMB_STRUCT_STAT sbuf;
 400         int i;
 401         struct notify_message msg;
 402         DATA_BLOB blob;
 403
 404         struct process_id *pids;
 405         int num_pids;
 406
 407         DEBUG(10, ("notify_action: parent=%s, name=%s, action=%u\n",
 408                    parent, name, (unsigned)action));
 409
 410         if (SMB_VFS_STAT(conn, parent, &sbuf) != 0) {
 411                 /*
 412                  * Not 100% critical, ignore failure
 413                  */
 414                 return;
 415         }
 416
 417         if (!(lck = get_share_mode_lock(NULL, sbuf.st_dev, sbuf.st_ino,
 418                                         NULL, NULL))) {
 419                 return;
 420         }
 421
 422         msg.dev = sbuf.st_dev;
 423         msg.inode = sbuf.st_ino;
 424         msg.action = action;
 425         msg.name = CONST_DISCARD(char *, name);
 426
 427         blob = notify_message_to_buf(&msg);
 428         if (blob.data == NULL) {
 429                 DEBUG(0, ("notify_message_to_buf failed\n"));
 430                 return;
 431         }
 432
 433         pids = NULL;
 434         num_pids = 0;
 435
 436         become_root_uid_only();
 437
 438         for (i=0; i<lck->num_share_modes; i++) {
 439                 struct share_mode_entry *e = &lck->share_modes[i];
 440                 int j;
 441                 struct process_id *tmp;
 442
 443                 for (j=0; j<num_pids; j++) {
 444                         if (procid_equal(&e->pid, &pids[j])) {
 445                                 break;
 446                         }
 447                 }
 448
 449                 if (j < num_pids) {
 450                         /*
 451                          * Already sent to that process, skip it
 452                          */
 453                         continue;
 454                 }
 455
 456                 message_send_pid(lck->share_modes[i].pid, MSG_SMB_NOTIFY,
 457                                  blob.data, blob.length, True);
 458
 459                 if (!(tmp = TALLOC_REALLOC_ARRAY(lck, pids, struct process_id,
 460                                                  num_pids+1))) {
 461                         DEBUG(0, ("realloc failed\n"));
 462                         break;
 463                 }
 464                 pids = tmp;
 465                 pids[num_pids] = e->pid;
 466                 num_pids += 1;
 467         }
 468
 469         unbecome_root_uid_only();
 470
 471         data_blob_free(&blob);
 472         TALLOC_FREE(lck);
 473 }
 474
 475 static void notify_message_callback(int msgtype, struct process_id pid,
 476                                     void *buf, size_t len)
 477 {
 478         struct notify_message msg;
 479         files_struct *fsp;
 480         struct notify_change *changes, *change;
 481         struct change_notify *cnbp;
 482
 483         if (!buf_to_notify_message(buf, len, &msg)) {
 484                 return;
 485         }
 486
 487         DEBUG(10, ("Received notify_message for 0x%x/%.0f: %d\n",
 488                    (unsigned)msg.dev, (double)msg.inode, msg.action));
 489
 490         fsp = NULL;
 491
 492         for (cnbp = change_notify_list; cnbp != NULL; cnbp = cnbp->next) {
 493                 if ((cnbp->fsp->dev == msg.dev)
 494                     && (cnbp->fsp->inode == msg.inode)) {
 495                         break;
 496                 }
 497         }
 498
 499         if (cnbp != NULL) {
 500                 DEBUG(10, ("Found pending change notify for %s\n",
 501                            cnbp->fsp->fsp_name));
 502                 fsp = cnbp->fsp;
 503                 SMB_ASSERT(fsp->notify->num_changes == 0);
 504         }
 505
 506         if ((fsp == NULL)
 507             && !(fsp = file_find_dir_lowest_id(msg.dev, msg.inode))) {
 508                 DEBUG(10, ("notify_message: did not find fsp\n"));
 509                 return;
 510         }
 511
 512         if (!(changes = TALLOC_REALLOC_ARRAY(
 513                       fsp->notify, fsp->notify->changes,
 514                       struct notify_change, fsp->notify->num_changes+1))) {
 515                 DEBUG(0, ("talloc_realloc failed\n"));
 516                 return;
 517         }
 518
 519         fsp->notify->changes = changes;
 520
 521         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 522
 523         if (!(change->name = talloc_strdup(changes, msg.name))) {
 524                 DEBUG(0, ("talloc_strdup failed\n"));
 525                 return;
 526         }
 527         change->action = msg.action;
 528         fsp->notify->num_changes += 1;
 529
 530         if (cnbp != NULL) {
 531                 /*
 532                  * Respond directly, we have a someone waiting for this change
 533                  */
 534                 DEBUG(10, ("Found pending cn for %s, responding directly\n",
 535                            cnbp->fsp->fsp_name));
 536                 change_notify_reply(cnbp->request_buf, cnbp->max_param_count,
 537                                     cnbp->fsp);
 538                 change_notify_remove(cnbp);
 539                 return;
 540         }
 541 }
 542
 543 /****************************************************************************
 544  Initialise the change notify subsystem.
 545 ****************************************************************************/
 546
 547 BOOL init_change_notify(void)
 548 {
 549         cnotify = NULL;
 550
 551 #if HAVE_KERNEL_CHANGE_NOTIFY
 552         if (cnotify == NULL && lp_kernel_change_notify())
 553                 cnotify = kernel_notify_init();
 554 #endif
 555 #if HAVE_FAM_CHANGE_NOTIFY
 556         if (cnotify == NULL && lp_fam_change_notify())
 557                 cnotify = fam_notify_init();
 558 #endif
 559         if (!cnotify) cnotify = hash_notify_init();
 560
 561         if (!cnotify) {
 562                 DEBUG(0,("Failed to init change notify system\n"));
 563                 return False;
 564         }
 565
 566         message_register(MSG_SMB_NOTIFY, notify_message_callback);
 567
 568         return True;
 569 }