ovsdb/ovsdb.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2017 Nicira, Inc.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17
  18 #include "ovsdb.h"
  19
  20 #include "column.h"
  21 #include "file.h"
  22 #include "monitor.h"
  23 #include "openvswitch/json.h"
  24 #include "ovsdb-error.h"
  25 #include "ovsdb-parser.h"
  26 #include "ovsdb-types.h"
  27 #include "simap.h"
  28 #include "storage.h"
  29 #include "table.h"
  30 #include "transaction.h"
  31 #include "trigger.h"
  32
  33 #include "openvswitch/vlog.h"
  34 VLOG_DEFINE_THIS_MODULE(ovsdb);
  35
  36 struct ovsdb_schema *
  37 ovsdb_schema_create(const char *name, const char *version, const char *cksum)
  38 {
  39     struct ovsdb_schema *schema;
  40
  41     schema = xzalloc(sizeof *schema);
  42     schema->name = xstrdup(name);
  43     schema->version = xstrdup(version);
  44     schema->cksum = xstrdup(cksum);
  45     shash_init(&schema->tables);
  46
  47     return schema;
  48 }
  49
  50 struct ovsdb_schema *
  51 ovsdb_schema_clone(const struct ovsdb_schema *old)
  52 {
  53     struct ovsdb_schema *new;
  54     struct shash_node *node;
  55
  56     new = ovsdb_schema_create(old->name, old->version, old->cksum);
  57     SHASH_FOR_EACH (node, &old->tables) {
  58         const struct ovsdb_table_schema *ts = node->data;
  59
  60         shash_add(&new->tables, node->name, ovsdb_table_schema_clone(ts));
  61     }
  62     return new;
  63 }
  64
  65 void
  66 ovsdb_schema_destroy(struct ovsdb_schema *schema)
  67 {
  68     struct shash_node *node;
  69
  70     if (!schema) {
  71         return;
  72     }
  73
  74     SHASH_FOR_EACH (node, &schema->tables) {
  75         ovsdb_table_schema_destroy(node->data);
  76     }
  77     shash_destroy(&schema->tables);
  78     free(schema->name);
  79     free(schema->version);
  80     free(schema->cksum);
  81     free(schema);
  82 }
  83
  84 struct ovsdb_error *
  85 ovsdb_schema_from_file(const char *file_name, struct ovsdb_schema **schemap)
  86 {
  87     struct ovsdb_schema *schema;
  88     struct ovsdb_error *error;
  89     struct json *json;
  90
  91     *schemap = NULL;
  92     json = json_from_file(file_name);
  93     if (json->type == JSON_STRING) {
  94         error = ovsdb_error("failed to read schema",
  95                            "\"%s\" could not be read as JSON (%s)",
  96                            file_name, json_string(json));
  97         json_destroy(json);
  98         return error;
  99     }
 100
 101     error = ovsdb_schema_from_json(json, &schema);
 102     json_destroy(json);
 103     if (error) {
 104         return ovsdb_wrap_error(error,
 105                                 "failed to parse \"%s\" as ovsdb schema",
 106                                 file_name);
 107     }
 108
 109     *schemap = schema;
 110     return NULL;
 111 }
 112
 113 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
 114 ovsdb_schema_check_ref_table(struct ovsdb_column *column,
 115                              const struct shash *tables,
 116                              const struct ovsdb_base_type *base,
 117                              const char *base_name)
 118 {
 119     struct ovsdb_table_schema *refTable;
 120
 121     if (base->type != OVSDB_TYPE_UUID || !base->uuid.refTableName) {
 122         return NULL;
 123     }
 124
 125     refTable = shash_find_data(tables, base->uuid.refTableName);
 126     if (!refTable) {
 127         return ovsdb_syntax_error(NULL, NULL,
 128                                   "column %s %s refers to undefined table %s",
 129                                   column->name, base_name,
 130                                   base->uuid.refTableName);
 131     }
 132
 133     if (ovsdb_base_type_is_strong_ref(base) && !refTable->is_root) {
 134         /* We cannot allow a strong reference to a non-root table to be
 135          * ephemeral: if it is the only reference to a row, then replaying the
 136          * database log from disk will cause the referenced row to be deleted,
 137          * even though it did exist in memory.  If there are references to that
 138          * row later in the log (to modify it, to delete it, or just to point
 139          * to it), then this will yield a transaction error. */
 140         column->persistent = true;
 141     }
 142
 143     return NULL;
 144 }
 145
 146 /* Attempts to parse 's' as a version string in the format "<x>.<y>.<z>".  If
 147  * successful, stores each part of the version into 'version->x', 'version->y',
 148  * and 'version->z', respectively, and returns true.  On failure, returns
 149  * false. */
 150 bool
 151 ovsdb_parse_version(const char *s, struct ovsdb_version *version)
 152 {
 153     int n = -1;
 154     return (ovs_scan(s, "%u.%u.%u%n", &version->x, &version->y, &version->z,
 155                      &n)
 156             && n != -1 && s[n] == '\0');
 157 }
 158
 159 /* Returns true if 's' is a version string in the format "<x>.<y>.<z>",
 160  * otherwie false. */
 161 bool
 162 ovsdb_is_valid_version(const char *s)
 163 {
 164     struct ovsdb_version version;
 165     return ovsdb_parse_version(s, &version);
 166 }
 167
 168 /* Returns the number of tables in 'schema''s root set. */
 169 static size_t
 170 root_set_size(const struct ovsdb_schema *schema)
 171 {
 172     struct shash_node *node;
 173     size_t n_root = 0;
 174
 175     SHASH_FOR_EACH (node, &schema->tables) {
 176         struct ovsdb_table_schema *table = node->data;
 177
 178         n_root += table->is_root;
 179     }
 180     return n_root;
 181 }
 182
 183 struct ovsdb_error *
 184 ovsdb_schema_from_json(const struct json *json, struct ovsdb_schema **schemap)
 185 {
 186     struct ovsdb_schema *schema;
 187     const struct json *name, *tables, *version_json, *cksum;
 188     struct ovsdb_error *error;
 189     struct shash_node *node;
 190     struct ovsdb_parser parser;
 191     const char *version;
 192
 193     *schemap = NULL;
 194
 195     ovsdb_parser_init(&parser, json, "database schema");
 196     name = ovsdb_parser_member(&parser, "name", OP_ID);
 197     version_json = ovsdb_parser_member(&parser, "version",
 198                                        OP_STRING | OP_OPTIONAL);
 199     cksum = ovsdb_parser_member(&parser, "cksum", OP_STRING | OP_OPTIONAL);
 200     tables = ovsdb_parser_member(&parser, "tables", OP_OBJECT);
 201     error = ovsdb_parser_finish(&parser);
 202     if (error) {
 203         return error;
 204     }
 205
 206     if (version_json) {
 207         version = json_string(version_json);
 208         if (!ovsdb_is_valid_version(version)) {
 209             return ovsdb_syntax_error(json, NULL, "schema version \"%s\" not "
 210                                       "in format x.y.z", version);
 211         }
 212     } else {
 213         /* Backward compatibility with old databases. */
 214         version = "";
 215     }
 216
 217     schema = ovsdb_schema_create(json_string(name), version,
 218                                  cksum ? json_string(cksum) : "");
 219     SHASH_FOR_EACH (node, json_object(tables)) {
 220         struct ovsdb_table_schema *table;
 221
 222         if (node->name[0] == '_') {
 223             error = ovsdb_syntax_error(json, NULL, "names beginning with "
 224                                        "\"_\" are reserved");
 225         } else if (!ovsdb_parser_is_id(node->name)) {
 226             error = ovsdb_syntax_error(json, NULL, "name must be a valid id");
 227         } else {
 228             error = ovsdb_table_schema_from_json(node->data, node->name,
 229                                                  &table);
 230         }
 231         if (error) {
 232             ovsdb_schema_destroy(schema);
 233             return error;
 234         }
 235
 236         shash_add(&schema->tables, table->name, table);
 237     }
 238
 239     /* "isRoot" was not part of the original schema definition.  Before it was
 240      * added, there was no support for garbage collection.  So, for backward
 241      * compatibility, if the root set is empty then assume that every table is
 242      * in the root set. */
 243     if (root_set_size(schema) == 0) {
 244         SHASH_FOR_EACH (node, &schema->tables) {
 245             struct ovsdb_table_schema *table = node->data;
 246
 247             table->is_root = true;
 248         }
 249     }
 250
 251     /* Validate that all refTables refer to the names of tables that exist.
 252      *
 253      * Also force certain columns to be persistent, as explained in
 254      * ovsdb_schema_check_ref_table().  This requires 'is_root' to be known, so
 255      * this must follow the loop updating 'is_root' above. */
 256     SHASH_FOR_EACH (node, &schema->tables) {
 257         struct ovsdb_table_schema *table = node->data;
 258         struct shash_node *node2;
 259
 260         SHASH_FOR_EACH (node2, &table->columns) {
 261             struct ovsdb_column *column = node2->data;
 262
 263             error = ovsdb_schema_check_ref_table(column, &schema->tables,
 264                                                  &column->type.key, "key");
 265             if (!error) {
 266                 error = ovsdb_schema_check_ref_table(column, &schema->tables,
 267                                                      &column->type.value,
 268                                                      "value");
 269             }
 270             if (error) {
 271                 ovsdb_schema_destroy(schema);
 272                 return error;
 273             }
 274         }
 275     }
 276
 277     *schemap = schema;
 278     return NULL;
 279 }
 280
 281 struct json *
 282 ovsdb_schema_to_json(const struct ovsdb_schema *schema)
 283 {
 284     struct json *json, *tables;
 285     struct shash_node *node;
 286     bool default_is_root;
 287
 288     json = json_object_create();
 289     json_object_put_string(json, "name", schema->name);
 290     if (schema->version[0]) {
 291         json_object_put_string(json, "version", schema->version);
 292     }
 293     if (schema->cksum[0]) {
 294         json_object_put_string(json, "cksum", schema->cksum);
 295     }
 296
 297     /* "isRoot" was not part of the original schema definition.  Before it was
 298      * added, there was no support for garbage collection.  So, for backward
 299      * compatibility, if every table is in the root set then do not output
 300      * "isRoot" in table schemas. */
 301     default_is_root = root_set_size(schema) == shash_count(&schema->tables);
 302
 303     tables = json_object_create();
 304
 305     SHASH_FOR_EACH (node, &schema->tables) {
 306         struct ovsdb_table_schema *table = node->data;
 307         json_object_put(tables, table->name,
 308                         ovsdb_table_schema_to_json(table, default_is_root));
 309     }
 310     json_object_put(json, "tables", tables);
 311
 312     return json;
 313 }
 314
 315 /* Returns true if 'a' and 'b' specify equivalent schemas, false if they
 316  * differ. */
 317 bool
 318 ovsdb_schema_equal(const struct ovsdb_schema *a,
 319                    const struct ovsdb_schema *b)
 320 {
 321     /* This implementation is simple, stupid, and slow, but I doubt that it
 322      * will ever require much maintenance. */
 323     struct json *ja = ovsdb_schema_to_json(a);
 324     struct json *jb = ovsdb_schema_to_json(b);
 325     bool equals = json_equal(ja, jb);
 326     json_destroy(ja);
 327     json_destroy(jb);
 328
 329     return equals;
 330 }
 331
 332 struct ovsdb_error * OVS_WARN_UNUSED_RESULT
 333 ovsdb_schema_check_for_ephemeral_columns(const struct ovsdb_schema *schema)
 334 {
 335     struct shash_node *node;
 336     SHASH_FOR_EACH (node, &schema->tables) {
 337         struct ovsdb_table_schema *table = node->data;
 338         struct shash_node *node2;
 339
 340         SHASH_FOR_EACH (node2, &table->columns) {
 341             struct ovsdb_column *column = node2->data;
 342
 343             if (column->index >= OVSDB_N_STD_COLUMNS && !column->persistent) {
 344                 return ovsdb_syntax_error(
 345                     NULL, NULL, "Table %s column %s is ephemeral but "
 346                     "clustered databases do not support ephemeral columns.",
 347                     table->name, column->name);
 348             }
 349         }
 350     }
 351     return NULL;
 352 }
 353
 354 void
 355 ovsdb_schema_persist_ephemeral_columns(struct ovsdb_schema *schema,
 356                                        const char *filename)
 357 {
 358     int n = 0;
 359     const char *example_table = NULL;
 360     const char *example_column = NULL;
 361
 362     struct shash_node *node;
 363     SHASH_FOR_EACH (node, &schema->tables) {
 364         struct ovsdb_table_schema *table = node->data;
 365         struct shash_node *node2;
 366
 367         SHASH_FOR_EACH (node2, &table->columns) {
 368             struct ovsdb_column *column = node2->data;
 369
 370             if (column->index >= OVSDB_N_STD_COLUMNS && !column->persistent) {
 371                 column->persistent = true;
 372                 example_table = table->name;
 373                 example_column = column->name;
 374                 n++;
 375             }
 376         }
 377     }
 378
 379     if (n) {
 380         VLOG_WARN("%s: changed %d columns in '%s' database from ephemeral to "
 381                   "persistent, including '%s' column in '%s' table, because "
 382                   "clusters do not support ephemeral columns",
 383                   filename, n, schema->name, example_column, example_table);
 384     }
 385 }
 386 \f
 387 static void
 388 ovsdb_set_ref_table(const struct shash *tables,
 389                     struct ovsdb_base_type *base)
 390 {
 391     if (base->type == OVSDB_TYPE_UUID && base->uuid.refTableName) {
 392         struct ovsdb_table *table;
 393
 394         table = shash_find_data(tables, base->uuid.refTableName);
 395         base->uuid.refTable = table;
 396     }
 397 }
 398
 399 /* Creates and returns a new ovsdb based on 'schema' and 'storage' and takes
 400  * ownership of both.
 401  *
 402  * At least one of the arguments must be nonnull. */
 403 struct ovsdb *
 404 ovsdb_create(struct ovsdb_schema *schema, struct ovsdb_storage *storage)
 405 {
 406     struct shash_node *node;
 407     struct ovsdb *db;
 408
 409     db = xzalloc(sizeof *db);
 410     db->name = xstrdup(schema
 411                        ? schema->name
 412                        : ovsdb_storage_get_name(storage));
 413     db->schema = schema;
 414     db->storage = storage;
 415     ovs_list_init(&db->monitors);
 416     ovs_list_init(&db->triggers);
 417     db->run_triggers = false;
 418
 419     shash_init(&db->tables);
 420     if (schema) {
 421         SHASH_FOR_EACH (node, &schema->tables) {
 422             struct ovsdb_table_schema *ts = node->data;
 423             shash_add(&db->tables, node->name, ovsdb_table_create(ts));
 424         }
 425
 426         /* Set all the refTables. */
 427         SHASH_FOR_EACH (node, &schema->tables) {
 428             struct ovsdb_table_schema *table = node->data;
 429             struct shash_node *node2;
 430
 431             SHASH_FOR_EACH (node2, &table->columns) {
 432                 struct ovsdb_column *column = node2->data;
 433
 434                 ovsdb_set_ref_table(&db->tables, &column->type.key);
 435                 ovsdb_set_ref_table(&db->tables, &column->type.value);
 436             }
 437         }
 438     }
 439
 440     /* Use RBAC roles table if present. */
 441     db->rbac_role = ovsdb_get_table(db, "RBAC_Role");
 442
 443     return db;
 444 }
 445
 446 void
 447 ovsdb_destroy(struct ovsdb *db)
 448 {
 449     if (db) {
 450         struct shash_node *node;
 451
 452         /* Close the log. */
 453         ovsdb_storage_close(db->storage);
 454
 455         /* Remove all the monitors. */
 456         ovsdb_monitors_remove(db);
 457
 458         /* The caller must ensure that no triggers remain. */
 459         ovs_assert(ovs_list_is_empty(&db->triggers));
 460
 461         /* Delete all the tables.  This also deletes their schemas. */
 462         SHASH_FOR_EACH (node, &db->tables) {
 463             struct ovsdb_table *table = node->data;
 464             ovsdb_table_destroy(table);
 465         }
 466         shash_destroy(&db->tables);
 467
 468         /* The schemas, but not the table that points to them, were deleted in
 469          * the previous step, so we need to clear out the table.  We can't
 470          * destroy the table, because ovsdb_schema_destroy() will do that. */
 471         if (db->schema) {
 472             shash_clear(&db->schema->tables);
 473             ovsdb_schema_destroy(db->schema);
 474         }
 475
 476         free(db->name);
 477         free(db);
 478     }
 479 }
 480
 481 /* Adds some memory usage statistics for 'db' into 'usage', for use with
 482  * memory_report(). */
 483 void
 484 ovsdb_get_memory_usage(const struct ovsdb *db, struct simap *usage)
 485 {
 486     if (!db->schema) {
 487         return;
 488     }
 489
 490     const struct shash_node *node;
 491     unsigned int cells = 0;
 492
 493     SHASH_FOR_EACH (node, &db->tables) {
 494         const struct ovsdb_table *table = node->data;
 495         unsigned int n_columns = shash_count(&table->schema->columns);
 496         unsigned int n_rows = hmap_count(&table->rows);
 497
 498         cells += n_rows * n_columns;
 499     }
 500
 501     simap_increase(usage, "cells", cells);
 502 }
 503
 504 struct ovsdb_table *
 505 ovsdb_get_table(const struct ovsdb *db, const char *name)
 506 {
 507     return shash_find_data(&db->tables, name);
 508 }
 509
 510 struct ovsdb_error * OVS_WARN_UNUSED_RESULT
 511 ovsdb_snapshot(struct ovsdb *db)
 512 {
 513     if (!db->storage) {
 514         return NULL;
 515     }
 516
 517     struct json *schema = ovsdb_schema_to_json(db->schema);
 518     struct json *data = ovsdb_to_txn_json(db, "compacting database online");
 519     struct ovsdb_error *error = ovsdb_storage_store_snapshot(db->storage,
 520                                                              schema, data);
 521     json_destroy(schema);
 522     json_destroy(data);
 523     return error;
 524 }
 525
 526 void
 527 ovsdb_replace(struct ovsdb *dst, struct ovsdb *src)
 528 {
 529     /* Cancel monitors. */
 530     ovsdb_monitor_prereplace_db(dst);
 531
 532     /* Cancel triggers. */
 533     struct ovsdb_trigger *trigger, *next;
 534     LIST_FOR_EACH_SAFE (trigger, next, node, &dst->triggers) {
 535         ovsdb_trigger_prereplace_db(trigger);
 536     }
 537
 538     struct ovsdb_schema *tmp_schema = dst->schema;
 539     dst->schema = src->schema;
 540     src->schema = tmp_schema;
 541
 542     shash_swap(&dst->tables, &src->tables);
 543
 544     dst->rbac_role = ovsdb_get_table(dst, "RBAC_Role");
 545
 546     ovsdb_destroy(src);
 547 }