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 2 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, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /*
  22   this is the change notify database. It implements mechanisms for
  23   storing current change notify waiters in a tdb, and checking if a
  24   given event matches any of the stored notify waiiters.
  25 */
  26
  27 #include "includes.h"
  28 #include "system/filesys.h"
  29 #include "lib/tdb/include/tdb.h"
  30 #include "lib/tdb/include/tdbutil.h"
  31 #include "messaging/messaging.h"
  32 #include "db_wrap.h"
  33 #include "lib/messaging/irpc.h"
  34 #include "librpc/gen_ndr/ndr_notify.h"
  35 #include "dlinklist.h"
  36
  37 struct notify_context {
  38         struct tdb_wrap *w;
  39         uint32_t server;
  40         struct messaging_context *messaging_ctx;
  41         struct notify_list *list;
  42         struct notify_array *array;
  43 };
  44
  45
  46 struct notify_list {
  47         struct notify_list *next, *prev;
  48         void *private;
  49         void (*callback)(void *, const struct notify_event *);
  50 };
  51
  52 #define NOTIFY_KEY "notify array"
  53
  54 static NTSTATUS notify_remove_all(struct notify_context *notify);
  55 static void notify_handler(struct messaging_context *msg_ctx, void *private,
  56                            uint32_t msg_type, uint32_t server_id, DATA_BLOB *data);
  57
  58 /*
  59   destroy the notify context
  60 */
  61 static int notify_destructor(void *p)
  62 {
  63         struct notify_context *notify = talloc_get_type(p, struct notify_context);
  64         messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
  65         notify_remove_all(notify);
  66         return 0;
  67 }
  68
  69 /*
  70   Open up the notify.tdb database. You should close it down using
  71   talloc_free(). We need the messaging_ctx to allow for notifications
  72   via internal messages
  73 */
  74 struct notify_context *notify_init(TALLOC_CTX *mem_ctx, uint32_t server,
  75                                    struct messaging_context *messaging_ctx)
  76 {
  77         char *path;
  78         struct notify_context *notify;
  79
  80         notify = talloc(mem_ctx, struct notify_context);
  81         if (notify == NULL) {
  82                 return NULL;
  83         }
  84
  85         path = smbd_tmp_path(notify, "notify.tdb");
  86         notify->w = tdb_wrap_open(notify, path, 0,
  87                                TDB_DEFAULT,
  88                                O_RDWR|O_CREAT, 0600);
  89         talloc_free(path);
  90         if (notify->w == NULL) {
  91                 talloc_free(notify);
  92                 return NULL;
  93         }
  94
  95         notify->server = server;
  96         notify->messaging_ctx = messaging_ctx;
  97         notify->list = NULL;
  98         notify->array = NULL;
  99
 100         talloc_set_destructor(notify, notify_destructor);
 101
 102         /* register with the messaging subsystem for the notify
 103            message type */
 104         messaging_register(notify->messaging_ctx, notify,
 105                            MSG_PVFS_NOTIFY, notify_handler);
 106
 107         return notify;
 108 }
 109
 110 /*
 111   load the notify array
 112 */
 113 static NTSTATUS notify_load(struct notify_context *notify)
 114 {
 115         TDB_DATA dbuf;
 116         DATA_BLOB blob;
 117         NTSTATUS status;
 118
 119         talloc_free(notify->array);
 120         notify->array = talloc_zero(notify, struct notify_array);
 121         NT_STATUS_HAVE_NO_MEMORY(notify->array);
 122
 123         dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
 124         if (dbuf.dptr == NULL) {
 125                 return NT_STATUS_OK;
 126         }
 127
 128         blob.data = dbuf.dptr;
 129         blob.length = dbuf.dsize;
 130
 131         status = ndr_pull_struct_blob(&blob, notify->array, notify->array,
 132                                       (ndr_pull_flags_fn_t)ndr_pull_notify_array);
 133         free(dbuf.dptr);
 134
 135         return status;
 136 }
 137
 138
 139 /*
 140   save the notify array
 141 */
 142 static NTSTATUS notify_save(struct notify_context *notify)
 143 {
 144         TDB_DATA dbuf;
 145         DATA_BLOB blob;
 146         NTSTATUS status;
 147         int ret;
 148         TALLOC_CTX *tmp_ctx;
 149
 150         if (notify->array->num_entries == 0) {
 151                 ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
 152                 if (ret != 0) {
 153                         return NT_STATUS_INTERNAL_DB_CORRUPTION;
 154                 }
 155                 return NT_STATUS_OK;
 156         }
 157
 158         tmp_ctx = talloc_new(notify);
 159
 160         status = ndr_push_struct_blob(&blob, tmp_ctx, notify->array,
 161                                       (ndr_push_flags_fn_t)ndr_push_notify_array);
 162         if (!NT_STATUS_IS_OK(status)) {
 163                 talloc_free(tmp_ctx);
 164                 return status;
 165         }
 166
 167         dbuf.dptr = blob.data;
 168         dbuf.dsize = blob.length;
 169
 170         ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
 171         talloc_free(tmp_ctx);
 172         if (ret != 0) {
 173                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 174         }
 175
 176         return NT_STATUS_OK;
 177 }
 178
 179
 180 /*
 181   handle incoming notify messages
 182 */
 183 static void notify_handler(struct messaging_context *msg_ctx, void *private,
 184                            uint32_t msg_type, uint32_t server_id, DATA_BLOB *data)
 185 {
 186         struct notify_context *notify = talloc_get_type(private, struct notify_context);
 187         NTSTATUS status;
 188         struct notify_event ev;
 189         TALLOC_CTX *tmp_ctx = talloc_new(notify);
 190         struct notify_list *listel;
 191
 192         status = ndr_pull_struct_blob(data, tmp_ctx, &ev,
 193                                       (ndr_pull_flags_fn_t)ndr_pull_notify_event);
 194         if (!NT_STATUS_IS_OK(status)) {
 195                 talloc_free(tmp_ctx);
 196                 return;
 197         }
 198
 199         for (listel=notify->list;listel;listel=listel->next) {
 200                 if (listel->private == ev.private) {
 201                         listel->callback(listel->private, &ev);
 202                         break;
 203                 }
 204         }
 205
 206         talloc_free(tmp_ctx);
 207 }
 208
 209 /*
 210   add a notify watch. This is called when a notify is first setup on a open
 211   directory handle.
 212 */
 213 NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e,
 214                     void (*callback)(void *, const struct notify_event *),
 215                     void *private)
 216 {
 217         NTSTATUS status;
 218         struct notify_list *listel;
 219
 220         status = notify_load(notify);
 221         NT_STATUS_NOT_OK_RETURN(status);
 222
 223         notify->array->entries = talloc_realloc(notify->array, notify->array->entries,
 224                                                 struct notify_entry,
 225                                                 notify->array->num_entries+1);
 226
 227         if (notify->array->entries == NULL) {
 228                 return NT_STATUS_NO_MEMORY;
 229         }
 230
 231         notify->array->entries[notify->array->num_entries] = *e;
 232         notify->array->entries[notify->array->num_entries].private = private;
 233         notify->array->entries[notify->array->num_entries].server = notify->server;
 234         notify->array->num_entries++;
 235
 236         status = notify_save(notify);
 237         NT_STATUS_NOT_OK_RETURN(status);
 238
 239         listel = talloc(notify, struct notify_list);
 240         NT_STATUS_HAVE_NO_MEMORY(listel);
 241
 242         listel->private = private;
 243         listel->callback = callback;
 244         DLIST_ADD(notify->list, listel);
 245
 246         return status;
 247 }
 248
 249 /*
 250   remove a notify watch. Called when the directory handle is closed
 251 */
 252 NTSTATUS notify_remove(struct notify_context *notify, void *private)
 253 {
 254         NTSTATUS status;
 255         struct notify_list *listel;
 256         int i;
 257
 258         for (listel=notify->list;listel;listel=listel->next) {
 259                 if (listel->private == private) {
 260                         DLIST_REMOVE(notify->list, listel);
 261                         break;
 262                 }
 263         }
 264         if (listel == NULL) {
 265                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 266         }
 267
 268         status = notify_load(notify);
 269         NT_STATUS_NOT_OK_RETURN(status);
 270
 271         for (i=0;i<notify->array->num_entries;i++) {
 272                 if (notify->server == notify->array->entries[i].server &&
 273                     private == notify->array->entries[i].private) {
 274                         break;
 275                 }
 276         }
 277         if (i == notify->array->num_entries) {
 278                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 279         }
 280
 281         if (i < notify->array->num_entries-1) {
 282                 memmove(&notify->array->entries[i], &notify->array->entries[i+1],
 283                         sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
 284         }
 285         notify->array->num_entries--;
 286
 287         return notify_save(notify);
 288 }
 289
 290 /*
 291   remove all notify watches for this messaging server
 292 */
 293 static NTSTATUS notify_remove_all(struct notify_context *notify)
 294 {
 295         NTSTATUS status;
 296         int i;
 297
 298         if (notify->list == NULL) {
 299                 return NT_STATUS_OK;
 300         }
 301
 302         status = notify_load(notify);
 303         NT_STATUS_NOT_OK_RETURN(status);
 304
 305         for (i=0;i<notify->array->num_entries;i++) {
 306                 if (notify->server == notify->array->entries[i].server) {
 307                         if (i < notify->array->num_entries-1) {
 308                                 memmove(&notify->array->entries[i], &notify->array->entries[i+1],
 309                                         sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
 310                         }
 311                         i--;
 312                         notify->array->num_entries--;
 313                 }
 314         }
 315
 316
 317         return notify_save(notify);
 318 }
 319
 320
 321 /*
 322   see if a notify event matches
 323 */
 324 static BOOL notify_match(struct notify_context *notify, struct notify_entry *e,
 325                          const char *path, uint32_t action)
 326 {
 327         size_t len = strlen(e->path);
 328
 329         /* TODO: check action */
 330
 331         if (strncmp(path, e->path, len) != 0) {
 332                 return False;
 333         }
 334
 335         if (path[len] != '/') {
 336                 return False;
 337         }
 338
 339         if (!e->recursive) {
 340                 if (strchr(&path[len+1], '/') != NULL) {
 341                         return False;
 342                 }
 343         }
 344
 345         return True;
 346 }
 347
 348
 349 /*
 350   send a notify message to another messaging server
 351 */
 352 static void notify_send(struct notify_context *notify, struct notify_entry *e,
 353                         const char *path, uint32_t action)
 354 {
 355         struct notify_event ev;
 356         DATA_BLOB data;
 357         NTSTATUS status;
 358         TALLOC_CTX *tmp_ctx;
 359
 360         ev.action = action;
 361         ev.path = path;
 362         ev.private = e->private;
 363
 364         tmp_ctx = talloc_new(notify);
 365
 366         status = ndr_push_struct_blob(&data, tmp_ctx, &ev,
 367                                       (ndr_push_flags_fn_t)ndr_push_notify_event);
 368         if (!NT_STATUS_IS_OK(status)) {
 369                 talloc_free(tmp_ctx);
 370                 return;
 371         }
 372
 373         status = messaging_send(notify->messaging_ctx, e->server,
 374                                 MSG_PVFS_NOTIFY, &data);
 375         talloc_free(tmp_ctx);
 376 }
 377
 378 /*
 379   trigger a notify message for anyone waiting on a matching event
 380 */
 381 void notify_trigger(struct notify_context *notify,
 382                     uint32_t action, const char *path)
 383 {
 384         NTSTATUS status;
 385         int i;
 386
 387         status = notify_load(notify);
 388         if (!NT_STATUS_IS_OK(status)) {
 389                 return;
 390         }
 391
 392         /* this needs to be changed to a log(n) search */
 393         for (i=0;i<notify->array->num_entries;i++) {
 394                 if (notify_match(notify, &notify->array->entries[i], path, action)) {
 395                         notify_send(notify, &notify->array->entries[i],
 396                                     path + strlen(notify->array->entries[i].path) + 1,
 397                                     action);
 398                 }
 399         }
 400 }