ovsdb/ovsdb.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013 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 "openvswitch/json.h"
  22 #include "ovsdb-error.h"
  23 #include "ovsdb-parser.h"
  24 #include "ovsdb-types.h"
  25 #include "simap.h"
  26 #include "table.h"
  27 #include "transaction.h"
  28
  29 struct ovsdb_schema *
  30 ovsdb_schema_create(const char *name, const char *version, const char *cksum)
  31 {
  32     struct ovsdb_schema *schema;
  33
  34     schema = xzalloc(sizeof *schema);
  35     schema->name = xstrdup(name);
  36     schema->version = xstrdup(version);
  37     schema->cksum = xstrdup(cksum);
  38     shash_init(&schema->tables);
  39
  40     return schema;
  41 }
  42
  43 struct ovsdb_schema *
  44 ovsdb_schema_clone(const struct ovsdb_schema *old)
  45 {
  46     struct ovsdb_schema *new;
  47     struct shash_node *node;
  48
  49     new = ovsdb_schema_create(old->name, old->version, old->cksum);
  50     SHASH_FOR_EACH (node, &old->tables) {
  51         const struct ovsdb_table_schema *ts = node->data;
  52
  53         shash_add(&new->tables, node->name, ovsdb_table_schema_clone(ts));
  54     }
  55     return new;
  56 }
  57
  58 void
  59 ovsdb_schema_destroy(struct ovsdb_schema *schema)
  60 {
  61     struct shash_node *node;
  62
  63     if (!schema) {
  64         return;
  65     }
  66
  67     SHASH_FOR_EACH (node, &schema->tables) {
  68         ovsdb_table_schema_destroy(node->data);
  69     }
  70     shash_destroy(&schema->tables);
  71     free(schema->name);
  72     free(schema->version);
  73     free(schema->cksum);
  74     free(schema);
  75 }
  76
  77 struct ovsdb_error *
  78 ovsdb_schema_from_file(const char *file_name, struct ovsdb_schema **schemap)
  79 {
  80     struct ovsdb_schema *schema;
  81     struct ovsdb_error *error;
  82     struct json *json;
  83
  84     *schemap = NULL;
  85     json = json_from_file(file_name);
  86     if (json->type == JSON_STRING) {
  87         error = ovsdb_error("failed to read schema",
  88                            "\"%s\" could not be read as JSON (%s)",
  89                            file_name, json_string(json));
  90         json_destroy(json);
  91         return error;
  92     }
  93
  94     error = ovsdb_schema_from_json(json, &schema);
  95     json_destroy(json);
  96     if (error) {
  97         return ovsdb_wrap_error(error,
  98                                 "failed to parse \"%s\" as ovsdb schema",
  99                                 file_name);
 100     }
 101
 102     *schemap = schema;
 103     return NULL;
 104 }
 105
 106 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
 107 ovsdb_schema_check_ref_table(struct ovsdb_column *column,
 108                              const struct shash *tables,
 109                              const struct ovsdb_base_type *base,
 110                              const char *base_name)
 111 {
 112     struct ovsdb_table_schema *refTable;
 113
 114     if (base->type != OVSDB_TYPE_UUID || !base->u.uuid.refTableName) {
 115         return NULL;
 116     }
 117
 118     refTable = shash_find_data(tables, base->u.uuid.refTableName);
 119     if (!refTable) {
 120         return ovsdb_syntax_error(NULL, NULL,
 121                                   "column %s %s refers to undefined table %s",
 122                                   column->name, base_name,
 123                                   base->u.uuid.refTableName);
 124     }
 125
 126     if (ovsdb_base_type_is_strong_ref(base) && !refTable->is_root) {
 127         /* We cannot allow a strong reference to a non-root table to be
 128          * ephemeral: if it is the only reference to a row, then replaying the
 129          * database log from disk will cause the referenced row to be deleted,
 130          * even though it did exist in memory.  If there are references to that
 131          * row later in the log (to modify it, to delete it, or just to point
 132          * to it), then this will yield a transaction error. */
 133         column->persistent = true;
 134     }
 135
 136     return NULL;
 137 }
 138
 139 static bool
 140 is_valid_version(const char *s)
 141 {
 142     int n = -1;
 143     ignore(ovs_scan(s, "%*[0-9].%*[0-9].%*[0-9]%n", &n));
 144     return n != -1 && s[n] == '\0';
 145 }
 146
 147 /* Returns the number of tables in 'schema''s root set. */
 148 static size_t
 149 root_set_size(const struct ovsdb_schema *schema)
 150 {
 151     struct shash_node *node;
 152     size_t n_root = 0;
 153
 154     SHASH_FOR_EACH (node, &schema->tables) {
 155         struct ovsdb_table_schema *table = node->data;
 156
 157         n_root += table->is_root;
 158     }
 159     return n_root;
 160 }
 161
 162 struct ovsdb_error *
 163 ovsdb_schema_from_json(struct json *json, struct ovsdb_schema **schemap)
 164 {
 165     struct ovsdb_schema *schema;
 166     const struct json *name, *tables, *version_json, *cksum;
 167     struct ovsdb_error *error;
 168     struct shash_node *node;
 169     struct ovsdb_parser parser;
 170     const char *version;
 171
 172     *schemap = NULL;
 173
 174     ovsdb_parser_init(&parser, json, "database schema");
 175     name = ovsdb_parser_member(&parser, "name", OP_ID);
 176     version_json = ovsdb_parser_member(&parser, "version",
 177                                        OP_STRING | OP_OPTIONAL);
 178     cksum = ovsdb_parser_member(&parser, "cksum", OP_STRING | OP_OPTIONAL);
 179     tables = ovsdb_parser_member(&parser, "tables", OP_OBJECT);
 180     error = ovsdb_parser_finish(&parser);
 181     if (error) {
 182         return error;
 183     }
 184
 185     if (version_json) {
 186         version = json_string(version_json);
 187         if (!is_valid_version(version)) {
 188             return ovsdb_syntax_error(json, NULL, "schema version \"%s\" not "
 189                                       "in format x.y.z", version);
 190         }
 191     } else {
 192         /* Backward compatibility with old databases. */
 193         version = "";
 194     }
 195
 196     schema = ovsdb_schema_create(json_string(name), version,
 197                                  cksum ? json_string(cksum) : "");
 198     SHASH_FOR_EACH (node, json_object(tables)) {
 199         struct ovsdb_table_schema *table;
 200
 201         if (node->name[0] == '_') {
 202             error = ovsdb_syntax_error(json, NULL, "names beginning with "
 203                                        "\"_\" are reserved");
 204         } else if (!ovsdb_parser_is_id(node->name)) {
 205             error = ovsdb_syntax_error(json, NULL, "name must be a valid id");
 206         } else {
 207             error = ovsdb_table_schema_from_json(node->data, node->name,
 208                                                  &table);
 209         }
 210         if (error) {
 211             ovsdb_schema_destroy(schema);
 212             return error;
 213         }
 214
 215         shash_add(&schema->tables, table->name, table);
 216     }
 217
 218     /* "isRoot" was not part of the original schema definition.  Before it was
 219      * added, there was no support for garbage collection.  So, for backward
 220      * compatibility, if the root set is empty then assume that every table is
 221      * in the root set. */
 222     if (root_set_size(schema) == 0) {
 223         SHASH_FOR_EACH (node, &schema->tables) {
 224             struct ovsdb_table_schema *table = node->data;
 225
 226             table->is_root = true;
 227         }
 228     }
 229
 230     /* Validate that all refTables refer to the names of tables that exist.
 231      *
 232      * Also force certain columns to be persistent, as explained in
 233      * ovsdb_schema_check_ref_table().  This requires 'is_root' to be known, so
 234      * this must follow the loop updating 'is_root' above. */
 235     SHASH_FOR_EACH (node, &schema->tables) {
 236         struct ovsdb_table_schema *table = node->data;
 237         struct shash_node *node2;
 238
 239         SHASH_FOR_EACH (node2, &table->columns) {
 240             struct ovsdb_column *column = node2->data;
 241
 242             error = ovsdb_schema_check_ref_table(column, &schema->tables,
 243                                                  &column->type.key, "key");
 244             if (!error) {
 245                 error = ovsdb_schema_check_ref_table(column, &schema->tables,
 246                                                      &column->type.value,
 247                                                      "value");
 248             }
 249             if (error) {
 250                 ovsdb_schema_destroy(schema);
 251                 return error;
 252             }
 253         }
 254     }
 255
 256     *schemap = schema;
 257     return NULL;
 258 }
 259
 260 struct json *
 261 ovsdb_schema_to_json(const struct ovsdb_schema *schema)
 262 {
 263     struct json *json, *tables;
 264     struct shash_node *node;
 265     bool default_is_root;
 266
 267     json = json_object_create();
 268     json_object_put_string(json, "name", schema->name);
 269     if (schema->version[0]) {
 270         json_object_put_string(json, "version", schema->version);
 271     }
 272     if (schema->cksum[0]) {
 273         json_object_put_string(json, "cksum", schema->cksum);
 274     }
 275
 276     /* "isRoot" was not part of the original schema definition.  Before it was
 277      * added, there was no support for garbage collection.  So, for backward
 278      * compatibility, if every table is in the root set then do not output
 279      * "isRoot" in table schemas. */
 280     default_is_root = root_set_size(schema) == shash_count(&schema->tables);
 281
 282     tables = json_object_create();
 283
 284     SHASH_FOR_EACH (node, &schema->tables) {
 285         struct ovsdb_table_schema *table = node->data;
 286         json_object_put(tables, table->name,
 287                         ovsdb_table_schema_to_json(table, default_is_root));
 288     }
 289     json_object_put(json, "tables", tables);
 290
 291     return json;
 292 }
 293
 294 /* Returns true if 'a' and 'b' specify equivalent schemas, false if they
 295  * differ. */
 296 bool
 297 ovsdb_schema_equal(const struct ovsdb_schema *a,
 298                    const struct ovsdb_schema *b)
 299 {
 300     /* This implementation is simple, stupid, and slow, but I doubt that it
 301      * will ever require much maintenance. */
 302     struct json *ja = ovsdb_schema_to_json(a);
 303     struct json *jb = ovsdb_schema_to_json(b);
 304     bool equals = json_equal(ja, jb);
 305     json_destroy(ja);
 306     json_destroy(jb);
 307
 308     return equals;
 309 }
 310 \f
 311 static void
 312 ovsdb_set_ref_table(const struct shash *tables,
 313                     struct ovsdb_base_type *base)
 314 {
 315     if (base->type == OVSDB_TYPE_UUID && base->u.uuid.refTableName) {
 316         struct ovsdb_table *table;
 317
 318         table = shash_find_data(tables, base->u.uuid.refTableName);
 319         base->u.uuid.refTable = table;
 320     }
 321 }
 322
 323 struct ovsdb *
 324 ovsdb_create(struct ovsdb_schema *schema)
 325 {
 326     struct shash_node *node;
 327     struct ovsdb *db;
 328
 329     db = xmalloc(sizeof *db);
 330     db->schema = schema;
 331     ovs_list_init(&db->replicas);
 332     ovs_list_init(&db->triggers);
 333     db->run_triggers = false;
 334
 335     shash_init(&db->tables);
 336     SHASH_FOR_EACH (node, &schema->tables) {
 337         struct ovsdb_table_schema *ts = node->data;
 338         shash_add(&db->tables, node->name, ovsdb_table_create(ts));
 339     }
 340
 341     /* Set all the refTables. */
 342     SHASH_FOR_EACH (node, &schema->tables) {
 343         struct ovsdb_table_schema *table = node->data;
 344         struct shash_node *node2;
 345
 346         SHASH_FOR_EACH (node2, &table->columns) {
 347             struct ovsdb_column *column = node2->data;
 348
 349             ovsdb_set_ref_table(&db->tables, &column->type.key);
 350             ovsdb_set_ref_table(&db->tables, &column->type.value);
 351         }
 352     }
 353
 354     /* Use RBAC roles table if present. */
 355     db->rbac_role = ovsdb_get_table(db, "RBAC_Role");
 356
 357     return db;
 358 }
 359
 360 void
 361 ovsdb_destroy(struct ovsdb *db)
 362 {
 363     if (db) {
 364         struct shash_node *node;
 365
 366         /* Remove all the replicas. */
 367         while (!ovs_list_is_empty(&db->replicas)) {
 368             struct ovsdb_replica *r
 369                 = CONTAINER_OF(ovs_list_pop_back(&db->replicas),
 370                                struct ovsdb_replica, node);
 371             ovsdb_remove_replica(db, r);
 372         }
 373
 374         /* Delete all the tables.  This also deletes their schemas. */
 375         SHASH_FOR_EACH (node, &db->tables) {
 376             struct ovsdb_table *table = node->data;
 377             ovsdb_table_destroy(table);
 378         }
 379         shash_destroy(&db->tables);
 380
 381         /* The schemas, but not the table that points to them, were deleted in
 382          * the previous step, so we need to clear out the table.  We can't
 383          * destroy the table, because ovsdb_schema_destroy() will do that. */
 384         shash_clear(&db->schema->tables);
 385
 386         ovsdb_schema_destroy(db->schema);
 387         free(db);
 388     }
 389 }
 390
 391 /* Adds some memory usage statistics for 'db' into 'usage', for use with
 392  * memory_report(). */
 393 void
 394 ovsdb_get_memory_usage(const struct ovsdb *db, struct simap *usage)
 395 {
 396     const struct shash_node *node;
 397     unsigned int cells = 0;
 398
 399     SHASH_FOR_EACH (node, &db->tables) {
 400         const struct ovsdb_table *table = node->data;
 401         unsigned int n_columns = shash_count(&table->schema->columns);
 402         unsigned int n_rows = hmap_count(&table->rows);
 403
 404         cells += n_rows * n_columns;
 405     }
 406
 407     simap_increase(usage, "cells", cells);
 408 }
 409
 410 struct ovsdb_table *
 411 ovsdb_get_table(const struct ovsdb *db, const char *name)
 412 {
 413     return shash_find_data(&db->tables, name);
 414 }
 415 \f
 416 void
 417 ovsdb_replica_init(struct ovsdb_replica *r,
 418                    const struct ovsdb_replica_class *class)
 419 {
 420     r->class = class;
 421 }
 422
 423 void
 424 ovsdb_add_replica(struct ovsdb *db, struct ovsdb_replica *r)
 425 {
 426     ovs_list_push_back(&db->replicas, &r->node);
 427 }
 428
 429 void
 430 ovsdb_remove_replica(struct ovsdb *db OVS_UNUSED, struct ovsdb_replica *r)
 431 {
 432     ovs_list_remove(&r->node);
 433     (r->class->destroy)(r);
 434 }