source4/ntvfs/common/notify.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Copyright (C) Andrew Tridgell 2006
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /*
  21   this is the change notify database. It implements mechanisms for
  22   storing current change notify waiters in a tdb, and checking if a
  23   given event matches any of the stored notify waiiters.
  24 */
  25
  26 #include "includes.h"
  27 #include "system/filesys.h"
  28 #include "../tdb/include/tdb.h"
  29 #include "../lib/util/util_tdb.h"
  30 #include "messaging/messaging.h"
  31 #include "tdb_wrap.h"
  32 #include "lib/messaging/irpc.h"
  33 #include "librpc/gen_ndr/ndr_notify.h"
  34 #include "../lib/util/dlinklist.h"
  35 #include "ntvfs/common/ntvfs_common.h"
  36 #include "ntvfs/sysdep/sys_notify.h"
  37 #include "cluster/cluster.h"
  38 #include "param/param.h"
  39
  40 struct notify_context {
  41         struct tdb_wrap *w;
  42         struct server_id server;
  43         struct messaging_context *messaging_ctx;
  44         struct notify_list *list;
  45         struct notify_array *array;
  46         int seqnum;
  47         struct sys_notify_context *sys_notify_ctx;
  48         struct smb_iconv_convenience *iconv_convenience;
  49 };
  50
  51
  52 struct notify_list {
  53         struct notify_list *next, *prev;
  54         void *private_data;
  55         void (*callback)(void *, const struct notify_event *);
  56         void *sys_notify_handle;
  57         int depth;
  58 };
  59
  60 #define NOTIFY_KEY "notify array"
  61
  62 #define NOTIFY_ENABLE           "notify:enable"
  63 #define NOTIFY_ENABLE_DEFAULT   true
  64
  65 static NTSTATUS notify_remove_all(struct notify_context *notify);
  66 static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
  67                            uint32_t msg_type, struct server_id server_id, DATA_BLOB *data);
  68
  69 /*
  70   destroy the notify context
  71 */
  72 static int notify_destructor(struct notify_context *notify)
  73 {
  74         messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
  75         notify_remove_all(notify);
  76         return 0;
  77 }
  78
  79 /*
  80   Open up the notify.tdb database. You should close it down using
  81   talloc_free(). We need the messaging_ctx to allow for notifications
  82   via internal messages
  83 */
  84 struct notify_context *notify_init(TALLOC_CTX *mem_ctx, struct server_id server,
  85                                    struct messaging_context *messaging_ctx,
  86                                    struct loadparm_context *lp_ctx,
  87                                    struct tevent_context *ev,
  88                                    struct share_config *scfg)
  89 {
  90         struct notify_context *notify;
  91
  92         if (share_bool_option(scfg, NOTIFY_ENABLE, NOTIFY_ENABLE_DEFAULT) != true) {
  93                 return NULL;
  94         }
  95
  96         if (ev == NULL) {
  97                 return NULL;
  98         }
  99
 100         notify = talloc(mem_ctx, struct notify_context);
 101         if (notify == NULL) {
 102                 return NULL;
 103         }
 104
 105         notify->w = cluster_tdb_tmp_open(notify, lp_ctx, "notify.tdb", TDB_SEQNUM);
 106         if (notify->w == NULL) {
 107                 talloc_free(notify);
 108                 return NULL;
 109         }
 110
 111         notify->server = server;
 112         notify->messaging_ctx = messaging_ctx;
 113         notify->list = NULL;
 114         notify->array = NULL;
 115         notify->iconv_convenience = lp_iconv_convenience(lp_ctx);
 116         notify->seqnum = tdb_get_seqnum(notify->w->tdb);
 117
 118         talloc_set_destructor(notify, notify_destructor);
 119
 120         /* register with the messaging subsystem for the notify
 121            message type */
 122         messaging_register(notify->messaging_ctx, notify,
 123                            MSG_PVFS_NOTIFY, notify_handler);
 124
 125         notify->sys_notify_ctx = sys_notify_context_create(scfg, notify, ev);
 126
 127         return notify;
 128 }
 129
 130
 131 /*
 132   lock the notify db
 133 */
 134 static NTSTATUS notify_lock(struct notify_context *notify)
 135 {
 136         if (tdb_lock_bystring(notify->w->tdb, NOTIFY_KEY) != 0) {
 137                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 138         }
 139         return NT_STATUS_OK;
 140 }
 141
 142 /*
 143   unlock the notify db
 144 */
 145 static void notify_unlock(struct notify_context *notify)
 146 {
 147         tdb_unlock_bystring(notify->w->tdb, NOTIFY_KEY);
 148 }
 149
 150 /*
 151   load the notify array
 152 */
 153 static NTSTATUS notify_load(struct notify_context *notify)
 154 {
 155         TDB_DATA dbuf;
 156         DATA_BLOB blob;
 157         enum ndr_err_code ndr_err;
 158         int seqnum;
 159
 160         seqnum = tdb_get_seqnum(notify->w->tdb);
 161
 162         if (seqnum == notify->seqnum && notify->array != NULL) {
 163                 return NT_STATUS_OK;
 164         }
 165
 166         notify->seqnum = seqnum;
 167
 168         talloc_free(notify->array);
 169         notify->array = talloc_zero(notify, struct notify_array);
 170         NT_STATUS_HAVE_NO_MEMORY(notify->array);
 171
 172         dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
 173         if (dbuf.dptr == NULL) {
 174                 return NT_STATUS_OK;
 175         }
 176
 177         blob.data = dbuf.dptr;
 178         blob.length = dbuf.dsize;
 179
 180         ndr_err = ndr_pull_struct_blob(&blob, notify->array, notify->iconv_convenience,
 181                                        notify->array,
 182                                        (ndr_pull_flags_fn_t)ndr_pull_notify_array);
 183         free(dbuf.dptr);
 184         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 185                 return ndr_map_error2ntstatus(ndr_err);
 186         }
 187
 188         return NT_STATUS_OK;
 189 }
 190
 191 /*
 192   compare notify entries for sorting
 193 */
 194 static int notify_compare(const void *p1, const void *p2)
 195 {
 196         const struct notify_entry *e1 = p1, *e2 = p2;
 197         return strcmp(e1->path, e2->path);
 198 }
 199
 200 /*
 201   save the notify array
 202 */
 203 static NTSTATUS notify_save(struct notify_context *notify)
 204 {
 205         TDB_DATA dbuf;
 206         DATA_BLOB blob;
 207         enum ndr_err_code ndr_err;
 208         int ret;
 209         TALLOC_CTX *tmp_ctx;
 210
 211         /* if possible, remove some depth arrays */
 212         while (notify->array->num_depths > 0 &&
 213                notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
 214                 notify->array->num_depths--;
 215         }
 216
 217         /* we might just be able to delete the record */
 218         if (notify->array->num_depths == 0) {
 219                 ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
 220                 if (ret != 0) {
 221                         return NT_STATUS_INTERNAL_DB_CORRUPTION;
 222                 }
 223                 return NT_STATUS_OK;
 224         }
 225
 226         tmp_ctx = talloc_new(notify);
 227         NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
 228
 229         ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, notify->iconv_convenience, notify->array,
 230                                        (ndr_push_flags_fn_t)ndr_push_notify_array);
 231         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 232                 talloc_free(tmp_ctx);
 233                 return ndr_map_error2ntstatus(ndr_err);
 234         }
 235
 236         dbuf.dptr = blob.data;
 237         dbuf.dsize = blob.length;
 238
 239         ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
 240         talloc_free(tmp_ctx);
 241         if (ret != 0) {
 242                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 243         }
 244
 245         return NT_STATUS_OK;
 246 }
 247
 248
 249 /*
 250   handle incoming notify messages
 251 */
 252 static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
 253                            uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
 254 {
 255         struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
 256         enum ndr_err_code ndr_err;
 257         struct notify_event ev;
 258         TALLOC_CTX *tmp_ctx = talloc_new(notify);
 259         struct notify_list *listel;
 260
 261         if (tmp_ctx == NULL) {
 262                 return;
 263         }
 264
 265         ndr_err = ndr_pull_struct_blob(data, tmp_ctx, notify->iconv_convenience, &ev,
 266                                       (ndr_pull_flags_fn_t)ndr_pull_notify_event);
 267         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 268                 talloc_free(tmp_ctx);
 269                 return;
 270         }
 271
 272         for (listel=notify->list;listel;listel=listel->next) {
 273                 if (listel->private_data == ev.private_data) {
 274                         listel->callback(listel->private_data, &ev);
 275                         break;
 276                 }
 277         }
 278
 279         talloc_free(tmp_ctx);
 280 }
 281
 282 /*
 283   callback from sys_notify telling us about changes from the OS
 284 */
 285 static void sys_notify_callback(struct sys_notify_context *ctx,
 286                                 void *ptr, struct notify_event *ev)
 287 {
 288         struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
 289         ev->private_data = listel;
 290         listel->callback(listel->private_data, ev);
 291 }
 292
 293 /*
 294   add an entry to the notify array
 295 */
 296 static NTSTATUS notify_add_array(struct notify_context *notify, struct notify_entry *e,
 297                                  void *private_data, int depth)
 298 {
 299         int i;
 300         struct notify_depth *d;
 301         struct notify_entry *ee;
 302
 303         /* possibly expand the depths array */
 304         if (depth >= notify->array->num_depths) {
 305                 d = talloc_realloc(notify->array, notify->array->depth,
 306                                    struct notify_depth, depth+1);
 307                 NT_STATUS_HAVE_NO_MEMORY(d);
 308                 for (i=notify->array->num_depths;i<=depth;i++) {
 309                         ZERO_STRUCT(d[i]);
 310                 }
 311                 notify->array->depth = d;
 312                 notify->array->num_depths = depth+1;
 313         }
 314         d = &notify->array->depth[depth];
 315
 316         /* expand the entries array */
 317         ee = talloc_realloc(notify->array->depth, d->entries, struct notify_entry,
 318                             d->num_entries+1);
 319         NT_STATUS_HAVE_NO_MEMORY(ee);
 320         d->entries = ee;
 321
 322         d->entries[d->num_entries] = *e;
 323         d->entries[d->num_entries].private_data = private_data;
 324         d->entries[d->num_entries].server = notify->server;
 325         d->entries[d->num_entries].path_len = strlen(e->path);
 326         d->num_entries++;
 327
 328         d->max_mask |= e->filter;
 329         d->max_mask_subdir |= e->subdir_filter;
 330
 331         if (d->num_entries > 1) {
 332                 qsort(d->entries, d->num_entries, sizeof(d->entries[0]), notify_compare);
 333         }
 334
 335         /* recalculate the maximum masks */
 336         d->max_mask = 0;
 337         d->max_mask_subdir = 0;
 338
 339         for (i=0;i<d->num_entries;i++) {
 340                 d->max_mask |= d->entries[i].filter;
 341                 d->max_mask_subdir |= d->entries[i].subdir_filter;
 342         }
 343
 344         return notify_save(notify);
 345 }
 346
 347 /*
 348   add a notify watch. This is called when a notify is first setup on a open
 349   directory handle.
 350 */
 351 NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e0,
 352                     void (*callback)(void *, const struct notify_event *),
 353                     void *private_data)
 354 {
 355         struct notify_entry e = *e0;
 356         NTSTATUS status;
 357         char *tmp_path = NULL;
 358         struct notify_list *listel;
 359         size_t len;
 360         int depth;
 361
 362         /* see if change notify is enabled at all */
 363         if (notify == NULL) {
 364                 return NT_STATUS_NOT_IMPLEMENTED;
 365         }
 366
 367         status = notify_lock(notify);
 368         NT_STATUS_NOT_OK_RETURN(status);
 369
 370         status = notify_load(notify);
 371         if (!NT_STATUS_IS_OK(status)) {
 372                 goto done;
 373         }
 374
 375         /* cope with /. on the end of the path */
 376         len = strlen(e.path);
 377         if (len > 1 && e.path[len-1] == '.' && e.path[len-2] == '/') {
 378                 tmp_path = talloc_strndup(notify, e.path, len-2);
 379                 if (tmp_path == NULL) {
 380                         status = NT_STATUS_NO_MEMORY;
 381                         goto done;
 382                 }
 383                 e.path = tmp_path;
 384         }
 385
 386         depth = count_chars(e.path, '/');
 387
 388         listel = talloc_zero(notify, struct notify_list);
 389         if (listel == NULL) {
 390                 status = NT_STATUS_NO_MEMORY;
 391                 goto done;
 392         }
 393
 394         listel->private_data = private_data;
 395         listel->callback = callback;
 396         listel->depth = depth;
 397         DLIST_ADD(notify->list, listel);
 398
 399         /* ignore failures from sys_notify */
 400         if (notify->sys_notify_ctx != NULL) {
 401                 /*
 402                   this call will modify e.filter and e.subdir_filter
 403                   to remove bits handled by the backend
 404                 */
 405                 status = sys_notify_watch(notify->sys_notify_ctx, &e,
 406                                           sys_notify_callback, listel,
 407                                           &listel->sys_notify_handle);
 408                 if (NT_STATUS_IS_OK(status)) {
 409                         talloc_steal(listel, listel->sys_notify_handle);
 410                 }
 411         }
 412
 413         /* if the system notify handler couldn't handle some of the
 414            filter bits, or couldn't handle a request for recursion
 415            then we need to install it in the array used for the
 416            intra-samba notify handling */
 417         if (e.filter != 0 || e.subdir_filter != 0) {
 418                 status = notify_add_array(notify, &e, private_data, depth);
 419         }
 420
 421 done:
 422         notify_unlock(notify);
 423         talloc_free(tmp_path);
 424
 425         return status;
 426 }
 427
 428 /*
 429   remove a notify watch. Called when the directory handle is closed
 430 */
 431 NTSTATUS notify_remove(struct notify_context *notify, void *private_data)
 432 {
 433         NTSTATUS status;
 434         struct notify_list *listel;
 435         int i, depth;
 436         struct notify_depth *d;
 437
 438         /* see if change notify is enabled at all */
 439         if (notify == NULL) {
 440                 return NT_STATUS_NOT_IMPLEMENTED;
 441         }
 442
 443         for (listel=notify->list;listel;listel=listel->next) {
 444                 if (listel->private_data == private_data) {
 445                         DLIST_REMOVE(notify->list, listel);
 446                         break;
 447                 }
 448         }
 449         if (listel == NULL) {
 450                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 451         }
 452
 453         depth = listel->depth;
 454
 455         talloc_free(listel);
 456
 457         status = notify_lock(notify);
 458         NT_STATUS_NOT_OK_RETURN(status);
 459
 460         status = notify_load(notify);
 461         if (!NT_STATUS_IS_OK(status)) {
 462                 notify_unlock(notify);
 463                 return status;
 464         }
 465
 466         if (depth >= notify->array->num_depths) {
 467                 notify_unlock(notify);
 468                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 469         }
 470
 471         /* we only have to search at the depth of this element */
 472         d = &notify->array->depth[depth];
 473
 474         for (i=0;i<d->num_entries;i++) {
 475                 if (private_data == d->entries[i].private_data &&
 476                     cluster_id_equal(&notify->server, &d->entries[i].server)) {
 477                         break;
 478                 }
 479         }
 480         if (i == d->num_entries) {
 481                 notify_unlock(notify);
 482                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 483         }
 484
 485         if (i < d->num_entries-1) {
 486                 memmove(&d->entries[i], &d->entries[i+1],
 487                         sizeof(d->entries[i])*(d->num_entries-(i+1)));
 488         }
 489         d->num_entries--;
 490
 491         status = notify_save(notify);
 492
 493         notify_unlock(notify);
 494
 495         return status;
 496 }
 497
 498 /*
 499   remove all notify watches for this messaging server
 500 */
 501 static NTSTATUS notify_remove_all(struct notify_context *notify)
 502 {
 503         NTSTATUS status;
 504         int i, depth, del_count=0;
 505
 506         if (notify->list == NULL) {
 507                 return NT_STATUS_OK;
 508         }
 509
 510         status = notify_lock(notify);
 511         NT_STATUS_NOT_OK_RETURN(status);
 512
 513         status = notify_load(notify);
 514         if (!NT_STATUS_IS_OK(status)) {
 515                 notify_unlock(notify);
 516                 return status;
 517         }
 518
 519         /* we have to search for all entries across all depths, looking for matches
 520            for our server id */
 521         for (depth=0;depth<notify->array->num_depths;depth++) {
 522                 struct notify_depth *d = &notify->array->depth[depth];
 523                 for (i=0;i<d->num_entries;i++) {
 524                         if (cluster_id_equal(&notify->server, &d->entries[i].server)) {
 525                                 if (i < d->num_entries-1) {
 526                                         memmove(&d->entries[i], &d->entries[i+1],
 527                                                 sizeof(d->entries[i])*(d->num_entries-(i+1)));
 528                                 }
 529                                 i--;
 530                                 d->num_entries--;
 531                                 del_count++;
 532                         }
 533                 }
 534         }
 535
 536         if (del_count > 0) {
 537                 status = notify_save(notify);
 538         }
 539
 540         notify_unlock(notify);
 541
 542         return status;
 543 }
 544
 545
 546 /*
 547   send a notify message to another messaging server
 548 */
 549 static void notify_send(struct notify_context *notify, struct notify_entry *e,
 550                         const char *path, uint32_t action)
 551 {
 552         struct notify_event ev;
 553         DATA_BLOB data;
 554         NTSTATUS status;
 555         enum ndr_err_code ndr_err;
 556         TALLOC_CTX *tmp_ctx;
 557
 558         ev.action = action;
 559         ev.path = path;
 560         ev.private_data = e->private_data;
 561
 562         tmp_ctx = talloc_new(notify);
 563
 564         ndr_err = ndr_push_struct_blob(&data, tmp_ctx, notify->iconv_convenience, &ev, (ndr_push_flags_fn_t)ndr_push_notify_event);
 565         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 566                 talloc_free(tmp_ctx);
 567                 return;
 568         }
 569
 570         status = messaging_send(notify->messaging_ctx, e->server,
 571                                 MSG_PVFS_NOTIFY, &data);
 572         talloc_free(tmp_ctx);
 573 }
 574
 575
 576 /*
 577   trigger a notify message for anyone waiting on a matching event
 578
 579   This function is called a lot, and needs to be very fast. The unusual data structure
 580   and traversal is designed to be fast in the average case, even for large numbers of
 581   notifies
 582 */
 583 void notify_trigger(struct notify_context *notify,
 584                     uint32_t action, uint32_t filter, const char *path)
 585 {
 586         NTSTATUS status;
 587         int depth;
 588         const char *p, *next_p;
 589
 590         /* see if change notify is enabled at all */
 591         if (notify == NULL) {
 592                 return;
 593         }
 594
 595         status = notify_load(notify);
 596         if (!NT_STATUS_IS_OK(status)) {
 597                 return;
 598         }
 599
 600         /* loop along the given path, working with each directory depth separately */
 601         for (depth=0,p=path;
 602              p && depth < notify->array->num_depths;
 603              p=next_p,depth++) {
 604                 int p_len = p - path;
 605                 int min_i, max_i, i;
 606                 struct notify_depth *d = &notify->array->depth[depth];
 607                 next_p = strchr(p+1, '/');
 608
 609                 /* see if there are any entries at this depth */
 610                 if (d->num_entries == 0) continue;
 611
 612                 /* try to skip based on the maximum mask. If next_p is
 613                  NULL then we know it will be a 'this directory'
 614                  match, otherwise it must be a subdir match */
 615                 if (next_p != NULL) {
 616                         if (0 == (filter & d->max_mask_subdir)) {
 617                                 continue;
 618                         }
 619                 } else {
 620                         if (0 == (filter & d->max_mask)) {
 621                                 continue;
 622                         }
 623                 }
 624
 625                 /* we know there is an entry here worth looking
 626                  for. Use a bisection search to find the first entry
 627                  with a matching path */
 628                 min_i = 0;
 629                 max_i = d->num_entries-1;
 630
 631                 while (min_i < max_i) {
 632                         struct notify_entry *e;
 633                         int cmp;
 634                         i = (min_i+max_i)/2;
 635                         e = &d->entries[i];
 636                         cmp = strncmp(path, e->path, p_len);
 637                         if (cmp == 0) {
 638                                 if (p_len == e->path_len) {
 639                                         max_i = i;
 640                                 } else {
 641                                         max_i = i-1;
 642                                 }
 643                         } else if (cmp < 0) {
 644                                 max_i = i-1;
 645                         } else {
 646                                 min_i = i+1;
 647                         }
 648                 }
 649
 650                 if (min_i != max_i) {
 651                         /* none match */
 652                         continue;
 653                 }
 654
 655                 /* we now know that the entries start at min_i */
 656                 for (i=min_i;i<d->num_entries;i++) {
 657                         struct notify_entry *e = &d->entries[i];
 658                         if (p_len != e->path_len ||
 659                             strncmp(path, e->path, p_len) != 0) break;
 660                         if (next_p != NULL) {
 661                                 if (0 == (filter & e->subdir_filter)) {
 662                                         continue;
 663                                 }
 664                         } else {
 665                                 if (0 == (filter & e->filter)) {
 666                                         continue;
 667                                 }
 668                         }
 669                         notify_send(notify, e, path + e->path_len + 1, action);
 670                 }
 671         }
 672 }