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         for (i=0; i<num_changes; i++) {
  70                 struct notify_change *c;
  71                 size_t namelen;
  72                 uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
  73                                  * signed/unsigned issues */
  74
  75                 /* Coalesce any identical records. */
  76                 while (i+1 < num_changes &&
  77                         notify_change_record_identical(&changes[i],
  78                                                 &changes[i+1])) {
  79                         i++;
  80                 }
  81
  82                 c = &changes[i];
  83
  84                 namelen = convert_string_allocate(
  85                         NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
  86                         &uni_name.buffer, True);
  87                 if ((namelen == -1) || (uni_name.buffer == NULL)) {
  88                         goto fail;
  89                 }
  90
  91                 namelen -= 2;   /* Dump NULL termination */
  92
  93                 /*
  94                  * Offset to next entry, only if there is one
  95                  */
  96
  97                 u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
  98                 if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;
  99
 100                 u32_tmp = c->action;
 101                 if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;
 102
 103                 u32_tmp = namelen;
 104                 if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;
 105
 106                 if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;
 107
 108                 /*
 109                  * Not NULL terminated, decrease by the 2 UCS2 \0 chars
 110                  */
 111                 prs_set_offset(ps, prs_offset(ps)-2);
 112
 113                 SAFE_FREE(uni_name.buffer);
 114
 115                 if (prs_offset(ps) > max_offset) {
 116                         /* Too much data for client. */
 117                         return False;
 118                 }
 119         }
 120
 121         return True;
 122
 123  fail:
 124         SAFE_FREE(uni_name.buffer);
 125         return False;
 126 }
 127
 128 /****************************************************************************
 129  Setup the common parts of the return packet and send it.
 130 *****************************************************************************/
 131
 132 static void change_notify_reply_packet(const char *request_buf,
 133                                        NTSTATUS error_code)
 134 {
 135         char outbuf[smb_size+38];
 136
 137         memset(outbuf, '\0', sizeof(outbuf));
 138         construct_reply_common(request_buf, outbuf);
 139
 140         ERROR_NT(error_code);
 141
 142         /*
 143          * Seems NT needs a transact command with an error code
 144          * in it. This is a longer packet than a simple error.
 145          */
 146         set_message(outbuf,18,0,False);
 147
 148         show_msg(outbuf);
 149         if (!send_smb(smbd_server_fd(),outbuf))
 150                 exit_server_cleanly("change_notify_reply_packet: send_smb "
 151                                     "failed.");
 152 }
 153
 154 void change_notify_reply(const char *request_buf, uint32 max_param,
 155                          struct notify_change_buf *notify_buf)
 156 {
 157         char *outbuf = NULL;
 158         prs_struct ps;
 159         size_t buflen;
 160
 161         if (notify_buf->num_changes == -1) {
 162                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 163                 notify_buf->num_changes = 0;
 164                 return;
 165         }
 166
 167         prs_init(&ps, 0, NULL, MARSHALL);
 168
 169         if (!notify_marshall_changes(notify_buf->num_changes, max_param,
 170                                         notify_buf->changes, &ps)) {
 171                 /*
 172                  * We exceed what the client is willing to accept. Send
 173                  * nothing.
 174                  */
 175                 change_notify_reply_packet(request_buf, NT_STATUS_OK);
 176                 goto done;
 177         }
 178
 179         buflen = smb_size+38+prs_offset(&ps) + 4 /* padding */;
 180
 181         if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
 182                 change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
 183                 goto done;
 184         }
 185
 186         construct_reply_common(request_buf, outbuf);
 187
 188         if (send_nt_replies(outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
 189                             prs_offset(&ps), NULL, 0) == -1) {
 190                 exit_server("change_notify_reply_packet: send_smb failed.");
 191         }
 192
 193  done:
 194         SAFE_FREE(outbuf);
 195         prs_mem_free(&ps);
 196
 197         TALLOC_FREE(notify_buf->changes);
 198         notify_buf->num_changes = 0;
 199 }
 200
 201 static void notify_callback(void *private_data, const struct notify_event *e)
 202 {
 203         files_struct *fsp = (files_struct *)private_data;
 204         DEBUG(10, ("notify_callback called for %s\n", fsp->fsp_name));
 205         notify_fsp(fsp, e->action, e->path);
 206 }
 207
 208 NTSTATUS change_notify_create(struct files_struct *fsp, uint32 filter,
 209                               BOOL recursive)
 210 {
 211         char *fullpath;
 212         struct notify_entry e;
 213         NTSTATUS status;
 214
 215         SMB_ASSERT(fsp->notify == NULL);
 216
 217         if (!(fsp->notify = TALLOC_ZERO_P(NULL, struct notify_change_buf))) {
 218                 DEBUG(0, ("talloc failed\n"));
 219                 return NT_STATUS_NO_MEMORY;
 220         }
 221
 222         if (asprintf(&fullpath, "%s/%s", fsp->conn->connectpath,
 223                      fsp->fsp_name) == -1) {
 224                 DEBUG(0, ("asprintf failed\n"));
 225                 return NT_STATUS_NO_MEMORY;
 226         }
 227
 228         e.path = fullpath;
 229         e.filter = filter;
 230         e.subdir_filter = 0;
 231         if (recursive) {
 232                 e.subdir_filter = filter;
 233         }
 234
 235         status = notify_add(fsp->conn->notify_ctx, &e, notify_callback, fsp);
 236         SAFE_FREE(fullpath);
 237
 238         return status;
 239 }
 240
 241 NTSTATUS change_notify_add_request(const char *inbuf, uint32 max_param,
 242                                    uint32 filter, BOOL recursive,
 243                                    struct files_struct *fsp)
 244 {
 245         struct notify_change_request *request = NULL;
 246         struct notify_mid_map *map = NULL;
 247
 248         if (!(request = SMB_MALLOC_P(struct notify_change_request))
 249             || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
 250                 SAFE_FREE(request);
 251                 return NT_STATUS_NO_MEMORY;
 252         }
 253
 254         request->mid_map = map;
 255         map->req = request;
 256
 257         memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
 258         request->max_param = max_param;
 259         request->filter = filter;
 260         request->fsp = fsp;
 261         request->backend_data = NULL;
 262
 263         DLIST_ADD_END(fsp->notify->requests, request,
 264                       struct notify_change_request *);
 265
 266         map->mid = SVAL(inbuf, smb_mid);
 267         DLIST_ADD(notify_changes_by_mid, map);
 268
 269         /* Push the MID of this packet on the signing queue. */
 270         srv_defer_sign_response(SVAL(inbuf,smb_mid));
 271
 272         return NT_STATUS_OK;
 273 }
 274
 275 static void change_notify_remove_request(struct notify_change_request *remove_req)
 276 {
 277         files_struct *fsp;
 278         struct notify_change_request *req;
 279
 280         /*
 281          * Paranoia checks, the fsp referenced must must have the request in
 282          * its list of pending requests
 283          */
 284
 285         fsp = remove_req->fsp;
 286         SMB_ASSERT(fsp->notify != NULL);
 287
 288         for (req = fsp->notify->requests; req; req = req->next) {
 289                 if (req == remove_req) {
 290                         break;
 291                 }
 292         }
 293
 294         if (req == NULL) {
 295                 smb_panic("notify_req not found in fsp's requests\n");
 296         }
 297
 298         DLIST_REMOVE(fsp->notify->requests, req);
 299         DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
 300         SAFE_FREE(req->mid_map);
 301         TALLOC_FREE(req->backend_data);
 302         SAFE_FREE(req);
 303 }
 304
 305 /****************************************************************************
 306  Delete entries by mid from the change notify pending queue. Always send reply.
 307 *****************************************************************************/
 308
 309 void remove_pending_change_notify_requests_by_mid(uint16 mid)
 310 {
 311         struct notify_mid_map *map;
 312
 313         for (map = notify_changes_by_mid; map; map = map->next) {
 314                 if (map->mid == mid) {
 315                         break;
 316                 }
 317         }
 318
 319         if (map == NULL) {
 320                 return;
 321         }
 322
 323         change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
 324         change_notify_remove_request(map->req);
 325 }
 326
 327 /****************************************************************************
 328  Delete entries by fnum from the change notify pending queue.
 329 *****************************************************************************/
 330
 331 void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
 332                                                   NTSTATUS status)
 333 {
 334         if (fsp->notify == NULL) {
 335                 return;
 336         }
 337
 338         while (fsp->notify->requests != NULL) {
 339                 change_notify_reply_packet(
 340                         fsp->notify->requests->request_buf, status);
 341                 change_notify_remove_request(fsp->notify->requests);
 342         }
 343 }
 344
 345 void notify_fname(connection_struct *conn, uint32 action, uint32 filter,
 346                   const char *path)
 347 {
 348         char *fullpath;
 349
 350         if (asprintf(&fullpath, "%s/%s", conn->connectpath, path) == -1) {
 351                 DEBUG(0, ("asprintf failed\n"));
 352                 return;
 353         }
 354
 355         notify_trigger(conn->notify_ctx, action, filter, fullpath);
 356         SAFE_FREE(fullpath);
 357 }
 358
 359 static void notify_fsp(files_struct *fsp, uint32 action, const char *name)
 360 {
 361         struct notify_change *change, *changes;
 362         pstring name2;
 363
 364         if (fsp->notify == NULL) {
 365                 /*
 366                  * Nobody is waiting, don't queue
 367                  */
 368                 return;
 369         }
 370
 371         pstrcpy(name2, name);
 372         string_replace(name2, '/', '\\');
 373
 374         /*
 375          * Someone has triggered a notify previously, queue the change for
 376          * later.
 377          */
 378
 379         if ((fsp->notify->num_changes > 1000) || (name == NULL)) {
 380                 /*
 381                  * The real number depends on the client buf, just provide a
 382                  * guard against a DoS here.
 383                  */
 384                 TALLOC_FREE(fsp->notify->changes);
 385                 fsp->notify->num_changes = -1;
 386                 return;
 387         }
 388
 389         if (fsp->notify->num_changes == -1) {
 390                 return;
 391         }
 392
 393         if (!(changes = TALLOC_REALLOC_ARRAY(
 394                       fsp->notify, fsp->notify->changes,
 395                       struct notify_change, fsp->notify->num_changes+1))) {
 396                 DEBUG(0, ("talloc_realloc failed\n"));
 397                 return;
 398         }
 399
 400         fsp->notify->changes = changes;
 401
 402         change = &(fsp->notify->changes[fsp->notify->num_changes]);
 403
 404         if (!(change->name = talloc_strdup(changes, name2))) {
 405                 DEBUG(0, ("talloc_strdup failed\n"));
 406                 return;
 407         }
 408
 409         change->action = action;
 410         fsp->notify->num_changes += 1;
 411
 412         if (fsp->notify->requests == NULL) {
 413                 /*
 414                  * Nobody is waiting, so don't send anything. The ot
 415                  */
 416                 return;
 417         }
 418
 419         if (action == NOTIFY_ACTION_OLD_NAME) {
 420                 /*
 421                  * We have to send the two rename events in one reply. So hold
 422                  * the first part back.
 423                  */
 424                 return;
 425         }
 426
 427         /*
 428          * Someone is waiting for the change, trigger the reply immediately.
 429          *
 430          * TODO: do we have to walk the lists of requests pending?
 431          */
 432
 433         change_notify_reply(fsp->notify->requests->request_buf,
 434                             fsp->notify->requests->max_param,
 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