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    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_count;
  31         uint32 current_bufsize;
  32         struct notify_mid_map *mid_map;
  33         void *backend_data;
  34 };
  35
  36 static void notify_fsp(files_struct *fsp, uint32 action, const char *name);
  37
  38 static struct notify_mid_map *notify_changes_by_mid;
  39
  40 /*
  41  * For NTCancel, we need to find the notify_change_request indexed by
  42  * mid. Separate list here.
  43  */
  44
  45 struct notify_mid_map {
  46         struct notify_mid_map *prev, *next;
  47         struct notify_change_request *req;
  48         uint16 mid;
  49 };
  50
  51 static BOOL notify_marshall_changes(int num_changes,
  52                                     struct notify_change *changes,
  53                                     prs_struct *ps)
  54 {
  55         int i;
  56         UNISTR uni_name;
  57
  58         for (i=0; i<num_changes; i++) {
  59                 struct notify_change *c = &changes[i];
  60                 size_t namelen;
  61                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  62                                  * signed/unsigned issues */
  63
  64                 namelen = convert_string_allocate(
  65                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  66                         &uni_name.buffer, True);
  67                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  68                         goto fail;
  69                 }
  70
  71                 namelen -= 2;   /* Dump NULL termination */
  72
  73                 /*
  74                  * Offset to next entry, only if there is one
  75                  */
  76
  77                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  78                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  79
  80                 u32_tmp = c->action;
  81                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
  82
  83                 u32_tmp = namelen;
  84                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
  85
  86                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
  87
  88                 /*
  89                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
  90                  */
  91                 prs_set_offset(ps, prs_offset(ps)-2);
  92
  93                 SAFE_FREE(uni_name.buffer);
  94         }
  95
  96         return True;
  97
  98  fail:
  99         SAFE_FREE(uni_name.buffer);
 100         return False;
 101 }
 102
 103 /****************************************************************************
 104  Setup the common parts of the return packet and send it.
 105 *****************************************************************************/
 106
 107 static void change_notify_reply_packet(const char *request_buf,
 108                                        NTSTATUS error_code)
 109 {
 110         const char *inbuf = request_buf;
 111         char outbuf[smb_size+38];
 112
 113         memset(outbuf, '\0', sizeof(outbuf));
 114         construct_reply_common(request_buf, outbuf);
 115
 116         ERROR_NT(error_code);
 117
 118         /*
 119          * Seems NT needs a transact command with an error code
 120          * in it. This is a longer packet than a simple error.
 121          */
 122         set_message(inbuf,outbuf,18,0,False);
 123
 124         show_msg(outbuf);
 125         if (!send_smb(smbd_server_fd(),outbuf))
 126                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 127                                     "failed.");
 128 }
 129
 130 void change_notify_reply(const char *request_buf, uint32 max_param_count,
 131                          struct notify_change_buf *notify_buf)
 132 {
 133         char *outbuf = NULL;
 134         prs_struct ps;
 135         size_t buflen = smb_size+38+max_param_count;
 136
 137         if (notify_buf->num_changes == -1) {
 138                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 139                 return;
 140         }
 141
 142         if (!prs_init(&ps, 0, NULL, False)
 143             || !notify_marshall_changes(notify_buf->num_changes,
 144                                         notify_buf->changes, &ps)) {
 145                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 146                 goto done;
 147         }
 148
 149         if (prs_offset(&ps) > max_param_count) {
 150                 /*
 151                  * We exceed what the client is willing to accept. Send
 152                  * nothing.
 153                  */
 154                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 155                 goto done;
 156         }
 157
 158         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 159                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 160                 goto done;
 161         }
 162
 163         construct_reply_common(request_buf, outbuf);
 164
 165         if (send_nt_replies(request_buf, outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 166                             prs_offset(&ps), NULL, 0) == -1) {
 167                 exit_server("change_notify_reply_packet: send_smb failed.");
 168         }
 169
 170  done:
 171         SAFE_FREE(outbuf);
 172         prs_mem_free(&ps);
 173
 174         TALLOC_FREE(notify_buf->changes);
 175         notify_buf->num_changes = 0;
 176 }
 177
 178 static void notify_callback(void *private_data, const struct notify_event *e)
 179 {
 180         files_struct *fsp = (files_struct *)private_data;
 181         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 182         notify_fsp(fsp, e->action, e->path);
 183 }
 184
 185 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 186                               BOOL recursive)
 187 {
 188         char *fullpath;
 189         struct notify_entry e;
 190         NTSTATUS status;
 191
 192         SMB_ASSERT(fsp->notify == NULL);
 193
 194         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 195                 DEBUG(0, ("talloc failed\n"));
 196                 return NT_STATUS_NO_MEMORY;
 197         }
 198
 199         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 200                      fsp->fsp_name) == -1) {
 201                 DEBUG(0, ("asprintf failed\n"));
 202                 return NT_STATUS_NO_MEMORY;
 203         }
 204
 205         e.path = fullpath;
 206         e.filter = filter;
 207         e.subdir_filter = 0;
 208         if (recursive) {
 209                 e.subdir_filter = filter;
 210         }
 211
 212         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 213         SAFE_FREE(fullpath);
 214
 215         return status;
 216 }
 217
 218 NTSTATUS change_notify_add_request(const char *inbuf, uint32 max_param_count,
 219                                    uint32 filter, BOOL recursive,
 220                                    struct files_struct *fsp)
 221 {
 222         struct notify_change_request *request = NULL;
 223         struct notify_mid_map *map = NULL;
 224
 225         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 226             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 227                 SAFE_FREE(request);
 228                 return NT_STATUS_NO_MEMORY;
 229         }
 230
 231         request->mid_map = map;
 232         map->req = request;
 233
 234         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 235         request->max_param_count = max_param_count;
 236         request->current_bufsize = 0;
 237         request->filter = filter;
 238         request->fsp = fsp;
 239         request->backend_data = NULL;
 240
 241         DLIST_ADD_END(fsp->notify->requests, request,
 242                       struct notify_change_request *);
 243
 244         map->mid = SVAL(inbuf, smb_mid);
 245         DLIST_ADD(notify_changes_by_mid, map);
 246
 247         /* Push the MID of this packet on the signing queue. */
 248         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 249
 250         return NT_STATUS_OK;
 251 }
 252
 253 static void change_notify_remove_request(struct notify_change_request *remove_req)
 254 {
 255         files_struct *fsp;
 256         struct notify_change_request *req;
 257
 258         /*
 259          * Paranoia checks, the fsp referenced must must have the request in
 260          * its list of pending requests
 261          */
 262
 263         fsp = remove_req->fsp;
 264         SMB_ASSERT(fsp->notify != NULL);
 265
 266         for (req = fsp->notify->requests; req; req = req->next) {
 267                 if (req == remove_req) {
 268                         break;
 269                 }
 270         }
 271
 272         if (req == NULL) {
 273                 smb_panic("notify_req not found in fsp's requests\n");
 274         }
 275
 276         DLIST_REMOVE(fsp->notify->requests, req);
 277         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 278         SAFE_FREE(req->mid_map);
 279         TALLOC_FREE(req->backend_data);
 280         SAFE_FREE(req);
 281 }
 282
 283 /****************************************************************************
 284  Delete entries by mid from the change notify pending queue. Always send reply.
 285 *****************************************************************************/
 286
 287 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 288 {
 289         struct notify_mid_map *map;
 290
 291         for (map = notify_changes_by_mid; map; map = map->next) {
 292                 if (map->mid == mid) {
 293                         break;
 294                 }
 295         }
 296
 297         if (map == NULL) {
 298                 return;
 299         }
 300
 301         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 302         change_notify_remove_request(map->req);
 303 }
 304
 305 /****************************************************************************
 306  Delete entries by fnum from the change notify pending queue.
 307 *****************************************************************************/
 308
 309 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 310                                                   NTSTATUS status)
 311 {
 312         if (fsp->notify == NULL) {
 313                 return;
 314         }
 315
 316         while (fsp->notify->requests != NULL) {
 317                 change_notify_reply_packet(
 318                         fsp->notify->requests->request_buf, status);
 319                 change_notify_remove_request(fsp->notify->requests);
 320         }
 321 }
 322
 323 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 324                   const char *path)
 325 {
 326         char *fullpath;
 327
 328         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 329                 DEBUG(0, ("asprintf failed\n"));
 330                 return;
 331         }
 332
 333         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 334         SAFE_FREE(fullpath);
 335 }
 336
 337 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 338 {
 339         struct notify_change *change, *changes;
 340         pstring name2;
 341
 342         if (fsp->notify == NULL) {
 343                 /*
 344                  * Nobody is waiting, don't queue
 345                  */
 346                 return;
 347         }
 348
 349         pstrcpy(name2, name);
 350         string_replace(name2, '/', '\\');
 351
 352         /*
 353          * Someone has triggered a notify previously, queue the change for
 354          * later.
 355          */
 356
 357         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 358                 /*
 359                  * The real number depends on the client buf, just provide a
 360                  * guard against a DoS here.
 361                  */
 362                 TALLOC_FREE(fsp->notify->changes);
 363                 fsp->notify->num_changes = -1;
 364                 return;
 365         }
 366
 367         if (fsp->notify->num_changes == -1) {
 368                 return;
 369         }
 370
 371         if (!(changes = TALLOC_REALLOC_ARRAY(
 372                       fsp->notify, fsp->notify->changes,
 373                       struct notify_change, fsp->notify->num_changes+1))) {
 374                 DEBUG(0, ("talloc_realloc failed\n"));
 375                 return;
 376         }
 377
 378         fsp->notify->changes = changes;
 379
 380         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 381
 382         if (!(change->name = talloc_strdup(changes, name2))) {
 383                 DEBUG(0, ("talloc_strdup failed\n"));
 384                 return;
 385         }
 386
 387         change->action = action;
 388         fsp->notify->num_changes += 1;
 389
 390         if (fsp->notify->requests == NULL) {
 391                 /*
 392                  * Nobody is waiting, so don't send anything. The ot
 393                  */
 394                 return;
 395         }
 396
 397         if (action == NOTIFY_ACTION_OLD_NAME) {
 398                 /*
 399                  * We have to send the two rename events in one reply. So hold
 400                  * the first part back.
 401                  */
 402                 return;
 403         }
 404
 405         /*
 406          * Someone is waiting for the change, trigger the reply immediately.
 407          *
 408          * TODO: do we have to walk the lists of requests pending?
 409          */
 410
 411         change_notify_reply(fsp->notify->requests->request_buf,
 412                             fsp->notify->requests->max_param_count,
 413                             fsp->notify);
 414
 415         change_notify_remove_request(fsp->notify->requests);
 416 }
 417
 418 char *notify_filter_string(TALLOC_CTX *mem_ctx, uint32 filter)
 419 {
 420         char *result = NULL;
 421
 422         result = talloc_strdup(mem_ctx, "");
 423
 424         if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 425                 result = talloc_asprintf_append(result, "FILE_NAME|");
 426         if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 427                 result = talloc_asprintf_append(result, "DIR_NAME|");
 428         if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 429                 result = talloc_asprintf_append(result, "ATTRIBUTES|");
 430         if (filter & FILE_NOTIFY_CHANGE_SIZE)
 431                 result = talloc_asprintf_append(result, "SIZE|");
 432         if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 433                 result = talloc_asprintf_append(result, "LAST_WRITE|");
 434         if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 435                 result = talloc_asprintf_append(result, "LAST_ACCESS|");
 436         if (filter & FILE_NOTIFY_CHANGE_CREATION)
 437                 result = talloc_asprintf_append(result, "CREATION|");
 438         if (filter & FILE_NOTIFY_CHANGE_EA)
 439                 result = talloc_asprintf_append(result, "EA|");
 440         if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 441                 result = talloc_asprintf_append(result, "SECURITY|");
 442         if (filter & FILE_NOTIFY_CHANGE_STREAM_NAME)
 443                 result = talloc_asprintf_append(result, "STREAM_NAME|");
 444         if (filter & FILE_NOTIFY_CHANGE_STREAM_SIZE)
 445                 result = talloc_asprintf_append(result, "STREAM_SIZE|");
 446         if (filter & FILE_NOTIFY_CHANGE_STREAM_WRITE)
 447                 result = talloc_asprintf_append(result, "STREAM_WRITE|");
 448
 449         if (result == NULL) return NULL;
 450         if (*result == '\0') return result;
 451
 452         result[strlen(result)-1] = '\0';
 453         return result;
 454 }
 455
 456 struct sys_notify_context *sys_notify_context_create(connection_struct *conn,
 457                                                      TALLOC_CTX *mem_ctx,
 458                                                      struct event_context *ev)
 459 {
 460         struct sys_notify_context *ctx;
 461
 462         if (!(ctx = TALLOC_P(mem_ctx, struct sys_notify_context))) {
 463                 DEBUG(0, ("talloc failed\n"));
 464                 return NULL;
 465         }
 466
 467         ctx->ev = ev;
 468         ctx->conn = conn;
 469         ctx->private_data = NULL;
 470         return ctx;
 471 }
 472
 473 NTSTATUS sys_notify_watch(struct sys_notify_context *ctx,
 474                           struct notify_entry *e,
 475                           void (*callback)(struct sys_notify_context *ctx,
 476                                            void *private_data,
 477                                            struct notify_event *ev),
 478                           void *private_data, void *handle)
 479 {
 480         return SMB_VFS_NOTIFY_WATCH(ctx->conn, ctx, e, callback, private_data,
 481                                     handle);
 482 }
 483