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 struct notify_change_request {
  26         struct notify_change_request *prev, *next;
  27         struct files_struct *fsp;       /* backpointer for cancel by mid */
  28         char request_buf[smb_size];
  29         uint32 filter;
  30         uint32 max_param;
  31         struct notify_mid_map *mid_map;
  32         void *backend_data;
  33 };
  34
  35 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  36
  37 static struct notify_mid_map *notify_changes_by_mid;
  38
  39 /*
  40  * For NTCancel, we need to find the notify_change_request indexed by
  41  * mid. Separate list here.
  42  */
  43
  44 struct notify_mid_map {
  45         struct notify_mid_map *prev, *next;
  46         struct notify_change_request *req;
  47         uint16 mid;
  48 };
  49
  50 static BOOL notify_change_record_identical(struct notify_change *c1,
  51                                         struct notify_change *c2)
  52 {
  53         /* Note this is deliberately case sensitive. */
  54         if (c1->action == c2->action &&
  55                         strcmp(c1->name, c2->name) == 0) {
  56                 return True;
  57         }
  58         return False;
  59 }
  60
  61 static BOOL notify_marshall_changes(int num_changes,
  62                                 uint32 max_offset,
  63                                 struct notify_change *changes,
  64                                 prs_struct *ps)
  65 {
  66         int i;
  67         UNISTR uni_name;
  68
  69         uni_name.buffer = NULL;
  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                 if (prs_offset(ps) > max_offset) {
 118                         /* Too much data for client. */
 119                         return False;
 120                 }
 121         }
 122
 123         return True;
 124
 125  fail:
 126         SAFE_FREE(uni_name.buffer);
 127         return False;
 128 }
 129
 130 /****************************************************************************
 131  Setup the common parts of the return packet and send it.
 132 *****************************************************************************/
 133
 134 static void change_notify_reply_packet(const char *request_buf,
 135                                        NTSTATUS error_code)
 136 {
 137         char outbuf[smb_size+38];
 138
 139         memset(outbuf, '\0', sizeof(outbuf));
 140         construct_reply_common(request_buf, outbuf);
 141
 142         ERROR_NT(error_code);
 143
 144         /*
 145          * Seems NT needs a transact command with an error code
 146          * in it. This is a longer packet than a simple error.
 147          */
 148         set_message(outbuf,18,0,False);
 149
 150         show_msg(outbuf);
 151         if (!send_smb(smbd_server_fd(),outbuf))
 152                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 153                                     "failed.");
 154 }
 155
 156 void change_notify_reply(const char *request_buf, uint32 max_param,
 157                          struct notify_change_buf *notify_buf)
 158 {
 159         char *outbuf = NULL;
 160         prs_struct ps;
 161         size_t buflen;
 162
 163         if (notify_buf->num_changes == -1) {
 164                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 165                 notify_buf->num_changes = 0;
 166                 return;
 167         }
 168
 169         prs_init(&ps, 0, NULL, MARSHALL);
 170
 171         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 172                                         notify_buf->changes, &ps)) {
 173                 /*
 174                  * We exceed what the client is willing to accept. Send
 175                  * nothing.
 176                  */
 177                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 178                 goto done;
 179         }
 180
 181         buflen = smb_size+38+prs_offset(&ps) + 4 /* padding */;
 182
 183         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 184                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 185                 goto done;
 186         }
 187
 188         construct_reply_common(request_buf, outbuf);
 189
 190         if (send_nt_replies(outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 191                             prs_offset(&ps), NULL, 0) == -1) {
 192                 exit_server("change_notify_reply_packet: send_smb failed.");
 193         }
 194
 195  done:
 196         SAFE_FREE(outbuf);
 197         prs_mem_free(&ps);
 198
 199         TALLOC_FREE(notify_buf->changes);
 200         notify_buf->num_changes = 0;
 201 }
 202
 203 static void notify_callback(void *private_data, const struct notify_event *e)
 204 {
 205         files_struct *fsp = (files_struct *)private_data;
 206         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 207         notify_fsp(fsp, e->action, e->path);
 208 }
 209
 210 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 211                               BOOL recursive)
 212 {
 213         char *fullpath;
 214         struct notify_entry e;
 215         NTSTATUS status;
 216
 217         SMB_ASSERT(fsp->notify == NULL);
 218
 219         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 220                 DEBUG(0, ("talloc failed\n"));
 221                 return NT_STATUS_NO_MEMORY;
 222         }
 223
 224         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 225                      fsp->fsp_name) == -1) {
 226                 DEBUG(0, ("asprintf failed\n"));
 227                 return NT_STATUS_NO_MEMORY;
 228         }
 229
 230         e.path = fullpath;
 231         e.filter = filter;
 232         e.subdir_filter = 0;
 233         if (recursive) {
 234                 e.subdir_filter = filter;
 235         }
 236
 237         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 238         SAFE_FREE(fullpath);
 239
 240         return status;
 241 }
 242
 243 NTSTATUS change_notify_add_request(const char *inbuf, uint32 max_param,
 244                                    uint32 filter, BOOL recursive,
 245                                    struct files_struct *fsp)
 246 {
 247         struct notify_change_request *request = NULL;
 248         struct notify_mid_map *map = NULL;
 249
 250         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 251             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 252                 SAFE_FREE(request);
 253                 return NT_STATUS_NO_MEMORY;
 254         }
 255
 256         request->mid_map = map;
 257         map->req = request;
 258
 259         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 260         request->max_param = max_param;
 261         request->filter = filter;
 262         request->fsp = fsp;
 263         request->backend_data = NULL;
 264
 265         DLIST_ADD_END(fsp->notify->requests, request,
 266                       struct notify_change_request *);
 267
 268         map->mid = SVAL(inbuf, smb_mid);
 269         DLIST_ADD(notify_changes_by_mid, map);
 270
 271         /* Push the MID of this packet on the signing queue. */
 272         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 273
 274         return NT_STATUS_OK;
 275 }
 276
 277 static void change_notify_remove_request(struct notify_change_request *remove_req)
 278 {
 279         files_struct *fsp;
 280         struct notify_change_request *req;
 281
 282         /*
 283          * Paranoia checks, the fsp referenced must must have the request in
 284          * its list of pending requests
 285          */
 286
 287         fsp = remove_req->fsp;
 288         SMB_ASSERT(fsp->notify != NULL);
 289
 290         for (req = fsp->notify->requests; req; req = req->next) {
 291                 if (req == remove_req) {
 292                         break;
 293                 }
 294         }
 295
 296         if (req == NULL) {
 297                 smb_panic("notify_req not found in fsp's requests\n");
 298         }
 299
 300         DLIST_REMOVE(fsp->notify->requests, req);
 301         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 302         SAFE_FREE(req->mid_map);
 303         TALLOC_FREE(req->backend_data);
 304         SAFE_FREE(req);
 305 }
 306
 307 /****************************************************************************
 308  Delete entries by mid from the change notify pending queue. Always send reply.
 309 *****************************************************************************/
 310
 311 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 312 {
 313         struct notify_mid_map *map;
 314
 315         for (map = notify_changes_by_mid; map; map = map->next) {
 316                 if (map->mid == mid) {
 317                         break;
 318                 }
 319         }
 320
 321         if (map == NULL) {
 322                 return;
 323         }
 324
 325         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 326         change_notify_remove_request(map->req);
 327 }
 328
 329 /****************************************************************************
 330  Delete entries by fnum from the change notify pending queue.
 331 *****************************************************************************/
 332
 333 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 334                                                   NTSTATUS status)
 335 {
 336         if (fsp->notify == NULL) {
 337                 return;
 338         }
 339
 340         while (fsp->notify->requests != NULL) {
 341                 change_notify_reply_packet(
 342                         fsp->notify->requests->request_buf, status);
 343                 change_notify_remove_request(fsp->notify->requests);
 344         }
 345 }
 346
 347 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 348                   const char *path)
 349 {
 350         char *fullpath;
 351
 352         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 353                 DEBUG(0, ("asprintf failed\n"));
 354                 return;
 355         }
 356
 357         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 358         SAFE_FREE(fullpath);
 359 }
 360
 361 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 362 {
 363         struct notify_change *change, *changes;
 364         pstring name2;
 365
 366         if (fsp->notify == NULL) {
 367                 /*
 368                  * Nobody is waiting, don't queue
 369                  */
 370                 return;
 371         }
 372
 373         pstrcpy(name2, name);
 374         string_replace(name2, '/', '\\');
 375
 376         /*
 377          * Someone has triggered a notify previously, queue the change for
 378          * later.
 379          */
 380
 381         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 382                 /*
 383                  * The real number depends on the client buf, just provide a
 384                  * guard against a DoS here.
 385                  */
 386                 TALLOC_FREE(fsp->notify->changes);
 387                 fsp->notify->num_changes = -1;
 388                 return;
 389         }
 390
 391         if (fsp->notify->num_changes == -1) {
 392                 return;
 393         }
 394
 395         if (!(changes = TALLOC_REALLOC_ARRAY(
 396                       fsp->notify, fsp->notify->changes,
 397                       struct notify_change, fsp->notify->num_changes+1))) {
 398                 DEBUG(0, ("talloc_realloc failed\n"));
 399                 return;
 400         }
 401
 402         fsp->notify->changes = changes;
 403
 404         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 405
 406         if (!(change->name = talloc_strdup(changes, name2))) {
 407                 DEBUG(0, ("talloc_strdup failed\n"));
 408                 return;
 409         }
 410
 411         change->action = action;
 412         fsp->notify->num_changes += 1;
 413
 414         if (fsp->notify->requests == NULL) {
 415                 /*
 416                  * Nobody is waiting, so don't send anything. The ot
 417                  */
 418                 return;
 419         }
 420
 421         if (action == NOTIFY_ACTION_OLD_NAME) {
 422                 /*
 423                  * We have to send the two rename events in one reply. So hold
 424                  * the first part back.
 425                  */
 426                 return;
 427         }
 428
 429         /*
 430          * Someone is waiting for the change, trigger the reply immediately.
 431          *
 432          * TODO: do we have to walk the lists of requests pending?
 433          */
 434
 435         change_notify_reply(fsp->notify->requests->request_buf,
 436                             fsp->notify->requests->max_param,
 437                             fsp->notify);
 438
 439         change_notify_remove_request(fsp->notify->requests);
 440 }
 441
 442 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 443 {
 444         char *result = NULL;
 445
 446         result = talloc_strdup(mem_ctx, "");
 447
 448         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 449                 result = talloc_asprintf_append(result, "FILE_NAME|");
 450         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 451                 result = talloc_asprintf_append(result, "DIR_NAME|");
 452         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 453                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 454         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 455                 result = talloc_asprintf_append(result, "SIZE|");
 456         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 457                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 458         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 459                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 460         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 461                 result = talloc_asprintf_append(result, "CREATION|");
 462         if (filter & FILE_NOTIFY_CHANGE_EA)
 463                 result = talloc_asprintf_append(result, "EA|");
 464         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 465                 result = talloc_asprintf_append(result, "SECURITY|");
 466         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 467                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 468         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 469                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 470         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 471                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 472
 473         if (result == NULL) return NULL;
 474         if (*result == '\0') return result;
 475
 476         result[strlen(result)-1] = '\0';
 477         return result;
 478 }
 479
 480 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 481                                                      TALLOC_CTX *mem_ctx,
 482                                                      struct event_context *ev)
 483 {
 484         struct sys_notify_context *ctx;
 485
 486         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 487                 DEBUG(0, ("talloc failed\n"));
 488                 return NULL;
 489         }
 490
 491         ctx->ev = ev;
 492         ctx->conn = conn;
 493         ctx->private_data = NULL;
 494         return ctx;
 495 }
 496
 497 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 498                           struct notify_entry *e,
 499                           void (*callback)(struct sys_notify_context *ctx,
 500                                            void *private_data,
 501                                            struct notify_event *ev),
 502                           void *private_data, void *handle)
 503 {
 504         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 505                                     handle);
 506 }
 507