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    Copyright (C) Volker Lendecke 2007
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 /* Max size we can send to client in a notify response. */
  26 extern int max_send;
  27
  28 struct notify_change_request {
  29         struct notify_change_request *prev, *next;
  30         struct files_struct *fsp;       /* backpointer for cancel by mid */
  31         char request_buf[smb_size];
  32         uint32 filter;
  33         uint32 current_bufsize;
  34         struct notify_mid_map *mid_map;
  35         void *backend_data;
  36 };
  37
  38 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  39
  40 static struct notify_mid_map *notify_changes_by_mid;
  41
  42 /*
  43  * For NTCancel, we need to find the notify_change_request indexed by
  44  * mid. Separate list here.
  45  */
  46
  47 struct notify_mid_map {
  48         struct notify_mid_map *prev, *next;
  49         struct notify_change_request *req;
  50         uint16 mid;
  51 };
  52
  53 static BOOL notify_change_record_identical(struct notify_change *c1,
  54                                         struct notify_change *c2)
  55 {
  56         /* Note this is deliberately case sensitive. */
  57         if (c1->action == c2->action &&
  58                         strcmp(c1->name, c2->name) == 0) {
  59                 return True;
  60         }
  61         return False;
  62 }
  63
  64 static BOOL notify_marshall_changes(int num_changes,
  65                                     struct notify_change *changes,
  66                                     prs_struct *ps)
  67 {
  68         int i;
  69         UNISTR uni_name;
  70
  71         for (i=0; i<num_changes; i++) {
  72                 struct notify_change *c;
  73                 size_t namelen;
  74                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  75                                  * signed/unsigned issues */
  76
  77                 /* Coalesce any identical records. */
  78                 while (i+1 < num_changes &&
  79                         notify_change_record_identical(&changes[i],
  80                                                 &changes[i+1])) {
  81                         i++;
  82                 }
  83
  84                 c = &changes[i];
  85
  86                 namelen = convert_string_allocate(
  87                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  88                         &uni_name.buffer, True);
  89                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  90                         goto fail;
  91                 }
  92
  93                 namelen -= 2;   /* Dump NULL termination */
  94
  95                 /*
  96                  * Offset to next entry, only if there is one
  97                  */
  98
  99                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
 100                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
 101
 102                 u32_tmp = c->action;
 103                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 104
 105                 u32_tmp = namelen;
 106                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 107
 108                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 109
 110                 /*
 111                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 112                  */
 113                 prs_set_offset(ps, prs_offset(ps)-2);
 114
 115                 SAFE_FREE(uni_name.buffer);
 116         }
 117
 118         return True;
 119
 120  fail:
 121         SAFE_FREE(uni_name.buffer);
 122         return False;
 123 }
 124
 125 /****************************************************************************
 126  Setup the common parts of the return packet and send it.
 127 *****************************************************************************/
 128
 129 static void change_notify_reply_packet(const char *request_buf,
 130                                        NTSTATUS error_code)
 131 {
 132         const char *inbuf = request_buf;
 133         char outbuf[smb_size+38];
 134
 135         memset(outbuf, '\0', sizeof(outbuf));
 136         construct_reply_common(request_buf, outbuf);
 137
 138         ERROR_NT(error_code);
 139
 140         /*
 141          * Seems NT needs a transact command with an error code
 142          * in it. This is a longer packet than a simple error.
 143          */
 144         set_message(inbuf,outbuf,18,0,False);
 145
 146         show_msg(outbuf);
 147         if (!send_smb(smbd_server_fd(),outbuf))
 148                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 149                                     "failed.");
 150 }
 151
 152 void change_notify_reply(const char *request_buf,
 153                          struct notify_change_buf *notify_buf)
 154 {
 155         char *outbuf = NULL;
 156         prs_struct ps;
 157         size_t buflen;
 158
 159         if (notify_buf->num_changes == -1) {
 160                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 161                 return;
 162         }
 163
 164         if (!prs_init(&ps, 0, NULL, False)
 165             || !notify_marshall_changes(notify_buf->num_changes,
 166                                         notify_buf->changes, &ps)) {
 167                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 168                 goto done;
 169         }
 170
 171         buflen = smb_size+38+prs_offset(&ps) + 4 /* padding */;
 172
 173         if (buflen > max_send) {
 174                 /*
 175                  * We exceed what the client is willing to accept. Send
 176                  * nothing.
 177                  */
 178                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 179                 goto done;
 180         }
 181
 182         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 183                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 184                 goto done;
 185         }
 186
 187         construct_reply_common(request_buf, outbuf);
 188
 189         if (send_nt_replies(request_buf, outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 190                             prs_offset(&ps), NULL, 0) == -1) {
 191                 exit_server("change_notify_reply_packet: send_smb failed.");
 192         }
 193
 194  done:
 195         SAFE_FREE(outbuf);
 196         prs_mem_free(&ps);
 197
 198         TALLOC_FREE(notify_buf->changes);
 199         notify_buf->num_changes = 0;
 200 }
 201
 202 static void notify_callback(void *private_data, const struct notify_event *e)
 203 {
 204         files_struct *fsp = (files_struct *)private_data;
 205         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 206         notify_fsp(fsp, e->action, e->path);
 207 }
 208
 209 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 210                               BOOL recursive)
 211 {
 212         char *fullpath;
 213         struct notify_entry e;
 214         NTSTATUS status;
 215
 216         SMB_ASSERT(fsp->notify == NULL);
 217
 218         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 219                 DEBUG(0, ("talloc failed\n"));
 220                 return NT_STATUS_NO_MEMORY;
 221         }
 222
 223         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 224                      fsp->fsp_name) == -1) {
 225                 DEBUG(0, ("asprintf failed\n"));
 226                 return NT_STATUS_NO_MEMORY;
 227         }
 228
 229         e.path = fullpath;
 230         e.filter = filter;
 231         e.subdir_filter = 0;
 232         if (recursive) {
 233                 e.subdir_filter = filter;
 234         }
 235
 236         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 237         SAFE_FREE(fullpath);
 238
 239         return status;
 240 }
 241
 242 NTSTATUS change_notify_add_request(const char *inbuf,
 243                                    uint32 filter, BOOL recursive,
 244                                    struct files_struct *fsp)
 245 {
 246         struct notify_change_request *request = NULL;
 247         struct notify_mid_map *map = NULL;
 248
 249         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 250             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 251                 SAFE_FREE(request);
 252                 return NT_STATUS_NO_MEMORY;
 253         }
 254
 255         request->mid_map = map;
 256         map->req = request;
 257
 258         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 259         request->current_bufsize = 0;
 260         request->filter = filter;
 261         request->fsp = fsp;
 262         request->backend_data = NULL;
 263
 264         DLIST_ADD_END(fsp->notify->requests, request,
 265                       struct notify_change_request *);
 266
 267         map->mid = SVAL(inbuf, smb_mid);
 268         DLIST_ADD(notify_changes_by_mid, map);
 269
 270         /* Push the MID of this packet on the signing queue. */
 271         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 272
 273         return NT_STATUS_OK;
 274 }
 275
 276 static void change_notify_remove_request(struct notify_change_request *remove_req)
 277 {
 278         files_struct *fsp;
 279         struct notify_change_request *req;
 280
 281         /*
 282          * Paranoia checks, the fsp referenced must must have the request in
 283          * its list of pending requests
 284          */
 285
 286         fsp = remove_req->fsp;
 287         SMB_ASSERT(fsp->notify != NULL);
 288
 289         for (req = fsp->notify->requests; req; req = req->next) {
 290                 if (req == remove_req) {
 291                         break;
 292                 }
 293         }
 294
 295         if (req == NULL) {
 296                 smb_panic("notify_req not found in fsp's requests");
 297         }
 298
 299         DLIST_REMOVE(fsp->notify->requests, req);
 300         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 301         SAFE_FREE(req->mid_map);
 302         TALLOC_FREE(req->backend_data);
 303         SAFE_FREE(req);
 304 }
 305
 306 /****************************************************************************
 307  Delete entries by mid from the change notify pending queue. Always send reply.
 308 *****************************************************************************/
 309
 310 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 311 {
 312         struct notify_mid_map *map;
 313
 314         for (map = notify_changes_by_mid; map; map = map->next) {
 315                 if (map->mid == mid) {
 316                         break;
 317                 }
 318         }
 319
 320         if (map == NULL) {
 321                 return;
 322         }
 323
 324         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 325         change_notify_remove_request(map->req);
 326 }
 327
 328 /****************************************************************************
 329  Delete entries by fnum from the change notify pending queue.
 330 *****************************************************************************/
 331
 332 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 333                                                   NTSTATUS status)
 334 {
 335         if (fsp->notify == NULL) {
 336                 return;
 337         }
 338
 339         while (fsp->notify->requests != NULL) {
 340                 change_notify_reply_packet(
 341                         fsp->notify->requests->request_buf, status);
 342                 change_notify_remove_request(fsp->notify->requests);
 343         }
 344 }
 345
 346 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 347                   const char *path)
 348 {
 349         char *fullpath;
 350
 351         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 352                 DEBUG(0, ("asprintf failed\n"));
 353                 return;
 354         }
 355
 356         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 357         SAFE_FREE(fullpath);
 358 }
 359
 360 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 361 {
 362         struct notify_change *change, *changes;
 363         char *tmp;
 364
 365         if (fsp->notify == NULL) {
 366                 /*
 367                  * Nobody is waiting, don't queue
 368                  */
 369                 return;
 370         }
 371
 372         /*
 373          * Someone has triggered a notify previously, queue the change for
 374          * later.
 375          */
 376
 377         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 378                 /*
 379                  * The real number depends on the client buf, just provide a
 380                  * guard against a DoS here.
 381                  */
 382                 TALLOC_FREE(fsp->notify->changes);
 383                 fsp->notify->num_changes = -1;
 384                 return;
 385         }
 386
 387         if (fsp->notify->num_changes == -1) {
 388                 return;
 389         }
 390
 391         if (!(changes = TALLOC_REALLOC_ARRAY(
 392                       fsp->notify, fsp->notify->changes,
 393                       struct notify_change, fsp->notify->num_changes+1))) {
 394                 DEBUG(0, ("talloc_realloc failed\n"));
 395                 return;
 396         }
 397
 398         fsp->notify->changes = changes;
 399
 400         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 401
 402         if (!(tmp = talloc_strdup(changes, name))) {
 403                 DEBUG(0, ("talloc_strdup failed\n"));
 404                 return;
 405         }
 406
 407         string_replace(tmp, '/', '\\');
 408         change->name = tmp;
 409
 410         change->action = action;
 411         fsp->notify->num_changes += 1;
 412
 413         if (fsp->notify->requests == NULL) {
 414                 /*
 415                  * Nobody is waiting, so don't send anything. The ot
 416                  */
 417                 return;
 418         }
 419
 420         if (action == NOTIFY_ACTION_OLD_NAME) {
 421                 /*
 422                  * We have to send the two rename events in one reply. So hold
 423                  * the first part back.
 424                  */
 425                 return;
 426         }
 427
 428         /*
 429          * Someone is waiting for the change, trigger the reply immediately.
 430          *
 431          * TODO: do we have to walk the lists of requests pending?
 432          */
 433
 434         change_notify_reply(fsp->notify->requests->request_buf,
 435                             fsp->notify);
 436
 437         change_notify_remove_request(fsp->notify->requests);
 438 }
 439
 440 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 441 {
 442         char *result = NULL;
 443
 444         result = talloc_strdup(mem_ctx, "");
 445
 446         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 447                 result = talloc_asprintf_append(result, "FILE_NAME|");
 448         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 449                 result = talloc_asprintf_append(result, "DIR_NAME|");
 450         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 451                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 452         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 453                 result = talloc_asprintf_append(result, "SIZE|");
 454         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 455                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 456         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 457                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 458         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 459                 result = talloc_asprintf_append(result, "CREATION|");
 460         if (filter & FILE_NOTIFY_CHANGE_EA)
 461                 result = talloc_asprintf_append(result, "EA|");
 462         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 463                 result = talloc_asprintf_append(result, "SECURITY|");
 464         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 465                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 466         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 467                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 468         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 469                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 470
 471         if (result == NULL) return NULL;
 472         if (*result == '\0') return result;
 473
 474         result[strlen(result)-1] = '\0';
 475         return result;
 476 }
 477
 478 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 479                                                      TALLOC_CTX *mem_ctx,
 480                                                      struct event_context *ev)
 481 {
 482         struct sys_notify_context *ctx;
 483
 484         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 485                 DEBUG(0, ("talloc failed\n"));
 486                 return NULL;
 487         }
 488
 489         ctx->ev = ev;
 490         ctx->conn = conn;
 491         ctx->private_data = NULL;
 492         return ctx;
 493 }
 494
 495 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 496                           struct notify_entry *e,
 497                           void (*callback)(struct sys_notify_context *ctx,
 498                                            void *private_data,
 499                                            struct notify_event *ev),
 500                           void *private_data, void *handle)
 501 {
 502         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 503                                     handle);
 504 }
 505