ovsdb/execution.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 <limits.h>
  21
  22 #include "column.h"
  23 #include "condition.h"
  24 #include "file.h"
  25 #include "openvswitch/json.h"
  26 #include "mutation.h"
  27 #include "ovsdb-data.h"
  28 #include "ovsdb-error.h"
  29 #include "ovsdb-parser.h"
  30 #include "query.h"
  31 #include "rbac.h"
  32 #include "row.h"
  33 #include "server.h"
  34 #include "table.h"
  35 #include "timeval.h"
  36 #include "transaction.h"
  37
  38 struct ovsdb_execution {
  39     struct ovsdb *db;
  40     const struct ovsdb_session *session;
  41     struct ovsdb_txn *txn;
  42     struct ovsdb_symbol_table *symtab;
  43     bool durable;
  44     const char *role;
  45     const char *id;
  46
  47     /* Triggers. */
  48     long long int elapsed_msec;
  49     long long int timeout_msec;
  50 };
  51
  52 typedef struct ovsdb_error *ovsdb_operation_executor(struct ovsdb_execution *,
  53                                                      struct ovsdb_parser *,
  54                                                      struct json *result);
  55
  56 static ovsdb_operation_executor ovsdb_execute_insert;
  57 static ovsdb_operation_executor ovsdb_execute_select;
  58 static ovsdb_operation_executor ovsdb_execute_update;
  59 static ovsdb_operation_executor ovsdb_execute_mutate;
  60 static ovsdb_operation_executor ovsdb_execute_delete;
  61 static ovsdb_operation_executor ovsdb_execute_wait;
  62 static ovsdb_operation_executor ovsdb_execute_commit;
  63 static ovsdb_operation_executor ovsdb_execute_abort;
  64 static ovsdb_operation_executor ovsdb_execute_comment;
  65 static ovsdb_operation_executor ovsdb_execute_assert;
  66
  67 static ovsdb_operation_executor *
  68 lookup_executor(const char *name, bool *read_only)
  69 {
  70     struct ovsdb_operation {
  71         const char *name;
  72         bool read_only;
  73         ovsdb_operation_executor *executor;
  74     };
  75
  76     static const struct ovsdb_operation operations[] = {
  77         { "insert", false, ovsdb_execute_insert },
  78         { "select", true, ovsdb_execute_select },
  79         { "update", false, ovsdb_execute_update },
  80         { "mutate", false, ovsdb_execute_mutate },
  81         { "delete", false, ovsdb_execute_delete },
  82         { "wait", true, ovsdb_execute_wait },
  83         { "commit", false, ovsdb_execute_commit },
  84         { "abort", true, ovsdb_execute_abort },
  85         { "comment", true, ovsdb_execute_comment },
  86         { "assert", true, ovsdb_execute_assert },
  87     };
  88
  89     size_t i;
  90
  91     for (i = 0; i < ARRAY_SIZE(operations); i++) {
  92         const struct ovsdb_operation *c = &operations[i];
  93         if (!strcmp(c->name, name)) {
  94             *read_only = c->read_only;
  95             return c->executor;
  96         }
  97     }
  98     return NULL;
  99 }
 100
 101 /* On success, returns a transaction and stores the results to return to the
 102  * client in '*resultsp'.
 103  *
 104  * On failure, returns NULL.  If '*resultsp' is nonnull, then it is the results
 105  * to return to the client.  If '*resultsp' is null, then the execution failed
 106  * due to an unsatisfied "wait" operation and '*timeout_msec' is the time at
 107  * which the transaction will time out.  (If 'timeout_msec' is null, this case
 108  * never occurs--instead, an unsatisfied "wait" unconditionally fails.) */
 109 struct ovsdb_txn *
 110 ovsdb_execute_compose(struct ovsdb *db, const struct ovsdb_session *session,
 111                       const struct json *params, bool read_only,
 112                       const char *role, const char *id,
 113                       long long int elapsed_msec, long long int *timeout_msec,
 114                       bool *durable, struct json **resultsp)
 115 {
 116     struct ovsdb_execution x;
 117     struct ovsdb_error *error;
 118     struct json *results;
 119     size_t n_operations;
 120     size_t i;
 121
 122     *durable = false;
 123     if (params->type != JSON_ARRAY
 124         || !params->array.n
 125         || params->array.elems[0]->type != JSON_STRING
 126         || strcmp(params->array.elems[0]->string, db->schema->name)) {
 127         if (params->type != JSON_ARRAY) {
 128             error = ovsdb_syntax_error(params, NULL, "array expected");
 129         } else {
 130             error = ovsdb_syntax_error(params, NULL, "database name expected "
 131                                        "as first parameter");
 132         }
 133
 134         *resultsp = ovsdb_error_to_json_free(error);
 135         return NULL;
 136     }
 137
 138     x.db = db;
 139     x.session = session;
 140     x.txn = ovsdb_txn_create(db);
 141     x.symtab = ovsdb_symbol_table_create();
 142     x.durable = false;
 143     x.role = role;
 144     x.id = id;
 145     x.elapsed_msec = elapsed_msec;
 146     x.timeout_msec = LLONG_MAX;
 147     results = NULL;
 148
 149     results = json_array_create_empty();
 150     n_operations = params->array.n - 1;
 151     error = NULL;
 152     for (i = 1; i <= n_operations; i++) {
 153         struct json *operation = params->array.elems[i];
 154         struct ovsdb_error *parse_error;
 155         struct ovsdb_parser parser;
 156         struct json *result;
 157         const struct json *op;
 158         const char *op_name = NULL;
 159         bool ro = false;
 160
 161         /* Parse and execute operation. */
 162         ovsdb_parser_init(&parser, operation,
 163                           "ovsdb operation %"PRIuSIZE" of %"PRIuSIZE, i,
 164                           n_operations);
 165         op = ovsdb_parser_member(&parser, "op", OP_ID);
 166         result = json_object_create();
 167         if (op) {
 168             op_name = json_string(op);
 169             ovsdb_operation_executor *executor = lookup_executor(op_name, &ro);
 170             if (executor) {
 171                 error = executor(&x, &parser, result);
 172             } else {
 173                 ovsdb_parser_raise_error(&parser, "No operation \"%s\"",
 174                                          op_name);
 175             }
 176         } else {
 177             ovs_assert(ovsdb_parser_has_error(&parser));
 178         }
 179
 180         /* A parse error overrides any other error.
 181          * An error overrides any other result. */
 182         parse_error = ovsdb_parser_finish(&parser);
 183         if (parse_error) {
 184             ovsdb_error_destroy(error);
 185             error = parse_error;
 186         }
 187         /* Create read-only violation error if there is one. */
 188         if (!ro && !error) {
 189             if (read_only) {
 190                 error = ovsdb_error("not allowed",
 191                                     "%s operation not allowed when "
 192                                     "database server is in read only mode",
 193                                     op_name);
 194             } else if (db->schema->name[0] == '_') {
 195                 error = ovsdb_error("not allowed",
 196                                     "%s operation not allowed on "
 197                                     "table in reserved database %s",
 198                                     op_name, db->schema->name);
 199             }
 200         }
 201         if (error) {
 202             json_destroy(result);
 203             json_array_add(results, ovsdb_error_to_json(error));
 204             if (!strcmp(ovsdb_error_get_tag(error), "not supported")
 205                 && timeout_msec) {
 206                 *timeout_msec = x.timeout_msec;
 207                 json_destroy(results);
 208                 results = NULL;
 209                 goto exit;
 210             }
 211             break;
 212         }
 213         json_array_add(results, result);
 214     }
 215     while (json_array(results)->n < n_operations) {
 216         json_array_add(results, json_null_create());
 217     }
 218
 219 exit:
 220     if (error) {
 221         ovsdb_txn_abort(x.txn);
 222         x.txn = NULL;
 223
 224         ovsdb_error_destroy(error);
 225     }
 226     *resultsp = results;
 227     *durable = x.durable;
 228     ovsdb_symbol_table_destroy(x.symtab);
 229
 230     return x.txn;
 231 }
 232
 233 struct json *
 234 ovsdb_execute(struct ovsdb *db, const struct ovsdb_session *session,
 235               const struct json *params, bool read_only,
 236               const char *role, const char *id,
 237               long long int elapsed_msec, long long int *timeout_msec)
 238 {
 239     bool durable;
 240     struct json *results;
 241     struct ovsdb_txn *txn = ovsdb_execute_compose(
 242         db, session, params, read_only, role, id, elapsed_msec, timeout_msec,
 243         &durable, &results);
 244     if (!txn) {
 245         return results;
 246     }
 247
 248     struct ovsdb_error *error = ovsdb_txn_propose_commit_block(txn, durable);
 249     if (error) {
 250         json_array_add(results, ovsdb_error_to_json(error));
 251         ovsdb_error_destroy(error);
 252     }
 253     return results;
 254 }
 255
 256 static struct ovsdb_error *
 257 ovsdb_execute_commit(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 258                      struct json *result OVS_UNUSED)
 259 {
 260     const struct json *durable;
 261
 262     durable = ovsdb_parser_member(parser, "durable", OP_BOOLEAN);
 263     if (durable && json_boolean(durable)) {
 264         x->durable = true;
 265     }
 266     return NULL;
 267 }
 268
 269 static struct ovsdb_error *
 270 ovsdb_execute_abort(struct ovsdb_execution *x OVS_UNUSED,
 271                     struct ovsdb_parser *parser OVS_UNUSED,
 272                     struct json *result OVS_UNUSED)
 273 {
 274     return ovsdb_error("aborted", "aborted by request");
 275 }
 276
 277 static struct ovsdb_table *
 278 parse_table(struct ovsdb_execution *x,
 279             struct ovsdb_parser *parser, const char *member)
 280 {
 281     struct ovsdb_table *table;
 282     const char *table_name;
 283     const struct json *json;
 284
 285     json = ovsdb_parser_member(parser, member, OP_ID);
 286     if (!json) {
 287         return NULL;
 288     }
 289     table_name = json_string(json);
 290
 291     table = shash_find_data(&x->db->tables, table_name);
 292     if (!table) {
 293         ovsdb_parser_raise_error(parser, "No table named %s.", table_name);
 294     }
 295     return table;
 296 }
 297
 298 static OVS_WARN_UNUSED_RESULT struct ovsdb_error *
 299 parse_row(const struct json *json, const struct ovsdb_table *table,
 300           struct ovsdb_symbol_table *symtab,
 301           struct ovsdb_row **rowp, struct ovsdb_column_set *columns)
 302 {
 303     struct ovsdb_error *error;
 304     struct ovsdb_row *row;
 305
 306     *rowp = NULL;
 307
 308     if (!table) {
 309         return OVSDB_BUG("null table");
 310     }
 311     if (!json) {
 312         return OVSDB_BUG("null row");
 313     }
 314
 315     row = ovsdb_row_create(table);
 316     error = ovsdb_row_from_json(row, json, symtab, columns);
 317     if (error) {
 318         ovsdb_row_destroy(row);
 319         return error;
 320     } else {
 321         *rowp = row;
 322         return NULL;
 323     }
 324 }
 325
 326 static struct ovsdb_error *
 327 ovsdb_execute_insert(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 328                      struct json *result)
 329 {
 330     struct ovsdb_table *table;
 331     struct ovsdb_row *row = NULL;
 332     const struct json *uuid_name, *row_json;
 333     struct ovsdb_error *error;
 334     struct uuid row_uuid;
 335
 336     table = parse_table(x, parser, "table");
 337     uuid_name = ovsdb_parser_member(parser, "uuid-name", OP_ID | OP_OPTIONAL);
 338     row_json = ovsdb_parser_member(parser, "row", OP_OBJECT);
 339     error = ovsdb_parser_get_error(parser);
 340     if (error) {
 341         return error;
 342     }
 343
 344     if (uuid_name) {
 345         struct ovsdb_symbol *symbol;
 346
 347         symbol = ovsdb_symbol_table_insert(x->symtab, json_string(uuid_name));
 348         if (symbol->created) {
 349             return ovsdb_syntax_error(uuid_name, "duplicate uuid-name",
 350                                       "This \"uuid-name\" appeared on an "
 351                                       "earlier \"insert\" operation.");
 352         }
 353         row_uuid = symbol->uuid;
 354         symbol->created = true;
 355     } else {
 356         uuid_generate(&row_uuid);
 357     }
 358
 359     if (!error) {
 360         error = parse_row(row_json, table, x->symtab, &row, NULL);
 361     }
 362     if (!error) {
 363         /* Check constraints for columns not included in "row", in case the
 364          * default values do not satisfy the constraints.  We could check only
 365          * the columns that have their default values by supplying an
 366          * ovsdb_column_set to parse_row() above, but I suspect that this is
 367          * cheaper.  */
 368         const struct shash_node *node;
 369
 370         SHASH_FOR_EACH (node, &table->schema->columns) {
 371             const struct ovsdb_column *column = node->data;
 372             const struct ovsdb_datum *datum = &row->fields[column->index];
 373
 374             /* If there are 0 keys or pairs, there's nothing to check.
 375              * If there is 1, it might be a default value.
 376              * If there are more, it can't be a default value, so the value has
 377              * already been checked. */
 378             if (datum->n == 1) {
 379                 error = ovsdb_datum_check_constraints(datum, &column->type);
 380                 if (error) {
 381                     break;
 382                 }
 383             }
 384         }
 385     }
 386
 387     if (!error && !ovsdb_rbac_insert(x->db, table, row, x->role, x->id)) {
 388         error = ovsdb_perm_error("RBAC rules for client \"%s\" role \"%s\" "
 389                                  "prohibit row insertion into table \"%s\".",
 390                                  x->id, x->role, table->schema->name);
 391     }
 392
 393     if (!error) {
 394         *ovsdb_row_get_uuid_rw(row) = row_uuid;
 395         ovsdb_txn_row_insert(x->txn, row);
 396         json_object_put(result, "uuid",
 397                         ovsdb_datum_to_json(&row->fields[OVSDB_COL_UUID],
 398                                             &ovsdb_type_uuid));
 399     } else {
 400         ovsdb_row_destroy(row);
 401     }
 402     return error;
 403 }
 404
 405 static struct ovsdb_error *
 406 ovsdb_execute_select(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 407                      struct json *result)
 408 {
 409     struct ovsdb_table *table;
 410     const struct json *where, *columns_json, *sort_json;
 411     struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
 412     struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
 413     struct ovsdb_column_set sort = OVSDB_COLUMN_SET_INITIALIZER;
 414     struct ovsdb_error *error;
 415
 416     table = parse_table(x, parser, "table");
 417     where = ovsdb_parser_member(parser, "where", OP_ARRAY);
 418     columns_json = ovsdb_parser_member(parser, "columns",
 419                                        OP_ARRAY | OP_OPTIONAL);
 420     sort_json = ovsdb_parser_member(parser, "sort", OP_ARRAY | OP_OPTIONAL);
 421
 422     error = ovsdb_parser_get_error(parser);
 423     if (!error) {
 424         error = ovsdb_condition_from_json(table->schema, where, x->symtab,
 425                                           &condition);
 426     }
 427     if (!error) {
 428         error = ovsdb_column_set_from_json(columns_json, table->schema,
 429                                            &columns);
 430     }
 431     if (!error) {
 432         error = ovsdb_column_set_from_json(sort_json, table->schema, &sort);
 433     }
 434     if (!error) {
 435         struct ovsdb_row_set rows = OVSDB_ROW_SET_INITIALIZER;
 436
 437         ovsdb_query_distinct(table, &condition, &columns, &rows);
 438         ovsdb_row_set_sort(&rows, &sort);
 439         json_object_put(result, "rows",
 440                         ovsdb_row_set_to_json(&rows, &columns));
 441
 442         ovsdb_row_set_destroy(&rows);
 443     }
 444
 445     ovsdb_column_set_destroy(&columns);
 446     ovsdb_column_set_destroy(&sort);
 447     ovsdb_condition_destroy(&condition);
 448
 449     return error;
 450 }
 451
 452 struct update_row_cbdata {
 453     size_t n_matches;
 454     struct ovsdb_txn *txn;
 455     const struct ovsdb_row *row;
 456     const struct ovsdb_column_set *columns;
 457     const char *role;
 458     const char *id;
 459 };
 460
 461 static bool
 462 update_row_cb(const struct ovsdb_row *row, void *ur_)
 463 {
 464     struct update_row_cbdata *ur = ur_;
 465
 466     ur->n_matches++;
 467     if (!ovsdb_row_equal_columns(row, ur->row, ur->columns)) {
 468         ovsdb_row_update_columns(ovsdb_txn_row_modify(ur->txn, row),
 469                                  ur->row, ur->columns);
 470     }
 471
 472     return true;
 473 }
 474
 475 static struct ovsdb_error *
 476 ovsdb_execute_update(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 477                      struct json *result)
 478 {
 479     struct ovsdb_table *table;
 480     const struct json *where, *row_json;
 481     struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
 482     struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
 483     struct ovsdb_row *row = NULL;
 484     struct update_row_cbdata ur;
 485     struct ovsdb_error *error;
 486
 487     table = parse_table(x, parser, "table");
 488     where = ovsdb_parser_member(parser, "where", OP_ARRAY);
 489     row_json = ovsdb_parser_member(parser, "row", OP_OBJECT);
 490     error = ovsdb_parser_get_error(parser);
 491     if (!error) {
 492         error = parse_row(row_json, table, x->symtab, &row, &columns);
 493     }
 494     if (!error) {
 495         size_t i;
 496
 497         for (i = 0; i < columns.n_columns; i++) {
 498             const struct ovsdb_column *column = columns.columns[i];
 499
 500             if (!column->mutable) {
 501                 error = ovsdb_syntax_error(parser->json,
 502                                            "constraint violation",
 503                                            "Cannot update immutable column %s "
 504                                            "in table %s.",
 505                                            column->name, table->schema->name);
 506                 break;
 507             }
 508         }
 509     }
 510     if (!error) {
 511         error = ovsdb_condition_from_json(table->schema, where, x->symtab,
 512                                           &condition);
 513     }
 514     if (!error) {
 515         ur.n_matches = 0;
 516         ur.txn = x->txn;
 517         ur.row = row;
 518         ur.columns = &columns;
 519         if (ovsdb_rbac_update(x->db, table, &columns, &condition, x->role,
 520                               x->id)) {
 521             ovsdb_query(table, &condition, update_row_cb, &ur);
 522         } else {
 523             error = ovsdb_perm_error("RBAC rules for client \"%s\" role "
 524                                      "\"%s\" prohibit modification of "
 525                                      "table \"%s\".",
 526                                      x->id, x->role, table->schema->name);
 527         }
 528         json_object_put(result, "count", json_integer_create(ur.n_matches));
 529     }
 530
 531     ovsdb_row_destroy(row);
 532     ovsdb_column_set_destroy(&columns);
 533     ovsdb_condition_destroy(&condition);
 534
 535     return error;
 536 }
 537
 538 struct mutate_row_cbdata {
 539     size_t n_matches;
 540     struct ovsdb_txn *txn;
 541     const struct ovsdb_mutation_set *mutations;
 542     struct ovsdb_error **error;
 543 };
 544
 545 static bool
 546 mutate_row_cb(const struct ovsdb_row *row, void *mr_)
 547 {
 548     struct mutate_row_cbdata *mr = mr_;
 549
 550     mr->n_matches++;
 551     *mr->error = ovsdb_mutation_set_execute(ovsdb_txn_row_modify(mr->txn, row),
 552                                             mr->mutations);
 553     return *mr->error == NULL;
 554 }
 555
 556 static struct ovsdb_error *
 557 ovsdb_execute_mutate(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 558                      struct json *result)
 559 {
 560     struct ovsdb_table *table;
 561     const struct json *where;
 562     const struct json *mutations_json;
 563     struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
 564     struct ovsdb_mutation_set mutations = OVSDB_MUTATION_SET_INITIALIZER;
 565     struct ovsdb_row *row = NULL;
 566     struct mutate_row_cbdata mr;
 567     struct ovsdb_error *error;
 568
 569     table = parse_table(x, parser, "table");
 570     where = ovsdb_parser_member(parser, "where", OP_ARRAY);
 571     mutations_json = ovsdb_parser_member(parser, "mutations", OP_ARRAY);
 572     error = ovsdb_parser_get_error(parser);
 573     if (!error) {
 574         error = ovsdb_mutation_set_from_json(table->schema, mutations_json,
 575                                              x->symtab, &mutations);
 576     }
 577     if (!error) {
 578         error = ovsdb_condition_from_json(table->schema, where, x->symtab,
 579                                           &condition);
 580     }
 581     if (!error) {
 582         mr.n_matches = 0;
 583         mr.txn = x->txn;
 584         mr.mutations = &mutations;
 585         mr.error = &error;
 586         if (ovsdb_rbac_mutate(x->db, table, &mutations, &condition, x->role,
 587                               x->id)) {
 588             ovsdb_query(table, &condition, mutate_row_cb, &mr);
 589         } else {
 590             error = ovsdb_perm_error("RBAC rules for client \"%s\" role "
 591                                      "\"%s\" prohibit mutate operation on "
 592                                      "table \"%s\".",
 593                                      x->id, x->role, table->schema->name);
 594         }
 595         json_object_put(result, "count", json_integer_create(mr.n_matches));
 596     }
 597
 598     ovsdb_row_destroy(row);
 599     ovsdb_mutation_set_destroy(&mutations);
 600     ovsdb_condition_destroy(&condition);
 601
 602     return error;
 603 }
 604
 605 struct delete_row_cbdata {
 606     size_t n_matches;
 607     const struct ovsdb_table *table;
 608     struct ovsdb_txn *txn;
 609 };
 610
 611 static bool
 612 delete_row_cb(const struct ovsdb_row *row, void *dr_)
 613 {
 614     struct delete_row_cbdata *dr = dr_;
 615
 616     dr->n_matches++;
 617     ovsdb_txn_row_delete(dr->txn, row);
 618
 619     return true;
 620 }
 621
 622 static struct ovsdb_error *
 623 ovsdb_execute_delete(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 624                      struct json *result)
 625 {
 626     struct ovsdb_table *table;
 627     const struct json *where;
 628     struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
 629     struct ovsdb_error *error;
 630
 631     where = ovsdb_parser_member(parser, "where", OP_ARRAY);
 632     table = parse_table(x, parser, "table");
 633     error = ovsdb_parser_get_error(parser);
 634     if (!error) {
 635         error = ovsdb_condition_from_json(table->schema, where, x->symtab,
 636                                           &condition);
 637     }
 638     if (!error) {
 639         struct delete_row_cbdata dr;
 640
 641         dr.n_matches = 0;
 642         dr.table = table;
 643         dr.txn = x->txn;
 644
 645         if (ovsdb_rbac_delete(x->db, table, &condition, x->role, x->id)) {
 646             ovsdb_query(table, &condition, delete_row_cb, &dr);
 647         } else {
 648             error = ovsdb_perm_error("RBAC rules for client \"%s\" role "
 649                                      "\"%s\" prohibit row deletion from "
 650                                      "table \"%s\".",
 651                                      x->id, x->role, table->schema->name);
 652         }
 653         json_object_put(result, "count", json_integer_create(dr.n_matches));
 654     }
 655
 656     ovsdb_condition_destroy(&condition);
 657
 658     return error;
 659 }
 660
 661 struct wait_auxdata {
 662     struct ovsdb_row_hash *actual;
 663     struct ovsdb_row_hash *expected;
 664     bool *equal;
 665 };
 666
 667 static bool
 668 ovsdb_execute_wait_query_cb(const struct ovsdb_row *row, void *aux_)
 669 {
 670     struct wait_auxdata *aux = aux_;
 671
 672     if (ovsdb_row_hash_contains(aux->expected, row)) {
 673         ovsdb_row_hash_insert(aux->actual, row);
 674         return true;
 675     } else {
 676         /* The query row isn't in the expected result set, so the actual and
 677          * expected results sets definitely differ and we can short-circuit the
 678          * rest of the query. */
 679         *aux->equal = false;
 680         return false;
 681     }
 682 }
 683
 684 static struct ovsdb_error *
 685 ovsdb_execute_wait(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 686                    struct json *result OVS_UNUSED)
 687 {
 688     struct ovsdb_table *table;
 689     const struct json *timeout, *where, *columns_json, *until, *rows;
 690     struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
 691     struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
 692     struct ovsdb_row_hash expected = OVSDB_ROW_HASH_INITIALIZER(expected);
 693     struct ovsdb_row_hash actual = OVSDB_ROW_HASH_INITIALIZER(actual);
 694     struct ovsdb_error *error;
 695     struct wait_auxdata aux;
 696     long long int timeout_msec = 0;
 697     size_t i;
 698
 699     timeout = ovsdb_parser_member(parser, "timeout", OP_NUMBER | OP_OPTIONAL);
 700     where = ovsdb_parser_member(parser, "where", OP_ARRAY);
 701     columns_json = ovsdb_parser_member(parser, "columns",
 702                                        OP_ARRAY | OP_OPTIONAL);
 703     until = ovsdb_parser_member(parser, "until", OP_STRING);
 704     rows = ovsdb_parser_member(parser, "rows", OP_ARRAY);
 705     table = parse_table(x, parser, "table");
 706     error = ovsdb_parser_get_error(parser);
 707     if (!error) {
 708         error = ovsdb_condition_from_json(table->schema, where, x->symtab,
 709                                           &condition);
 710     }
 711     if (!error) {
 712         error = ovsdb_column_set_from_json(columns_json, table->schema,
 713                                            &columns);
 714     }
 715     if (!error) {
 716         if (timeout) {
 717             timeout_msec = MIN(LLONG_MAX, json_real(timeout));
 718             if (timeout_msec < 0) {
 719                 error = ovsdb_syntax_error(timeout, NULL,
 720                                            "timeout must be nonnegative");
 721             } else if (timeout_msec < x->timeout_msec) {
 722                 x->timeout_msec = timeout_msec;
 723             }
 724         } else {
 725             timeout_msec = LLONG_MAX;
 726         }
 727     }
 728     if (!error) {
 729         if (strcmp(json_string(until), "==")
 730             && strcmp(json_string(until), "!=")) {
 731             error = ovsdb_syntax_error(until, NULL,
 732                                        "\"until\" must be \"==\" or \"!=\"");
 733         }
 734     }
 735     if (!error) {
 736         /* Parse "rows" into 'expected'. */
 737         ovsdb_row_hash_init(&expected, &columns);
 738         for (i = 0; i < rows->array.n; i++) {
 739             struct ovsdb_row *row;
 740
 741             row = ovsdb_row_create(table);
 742             error = ovsdb_row_from_json(row, rows->array.elems[i], x->symtab,
 743                                         NULL);
 744             if (error) {
 745                 ovsdb_row_destroy(row);
 746                 break;
 747             }
 748
 749             if (!ovsdb_row_hash_insert(&expected, row)) {
 750                 /* XXX Perhaps we should abort with an error or log a
 751                  * warning. */
 752                 ovsdb_row_destroy(row);
 753             }
 754         }
 755     }
 756     if (!error) {
 757         /* Execute query. */
 758         bool equal = true;
 759         ovsdb_row_hash_init(&actual, &columns);
 760         aux.actual = &actual;
 761         aux.expected = &expected;
 762         aux.equal = &equal;
 763         ovsdb_query(table, &condition, ovsdb_execute_wait_query_cb, &aux);
 764         if (equal) {
 765             /* We know that every row in 'actual' is also in 'expected'.  We
 766              * also know that all of the rows in 'actual' are distinct and that
 767              * all of the rows in 'expected' are distinct.  Therefore, if
 768              * 'actual' and 'expected' have the same number of rows, then they
 769              * have the same content. */
 770             size_t n_actual = ovsdb_row_hash_count(&actual);
 771             size_t n_expected = ovsdb_row_hash_count(&expected);
 772             equal = n_actual == n_expected;
 773         }
 774         if (!strcmp(json_string(until), "==") != equal) {
 775             if (timeout && x->elapsed_msec >= timeout_msec) {
 776                 if (x->elapsed_msec) {
 777                     error = ovsdb_error("timed out",
 778                                         "\"wait\" timed out after %lld ms",
 779                                         x->elapsed_msec);
 780                 } else {
 781                     error = ovsdb_error("timed out",
 782                                         "\"where\" clause test failed");
 783                 }
 784             } else {
 785                 /* ovsdb_execute() will change this, if triggers really are
 786                  * supported. */
 787                 error = ovsdb_error("not supported", "triggers not supported");
 788             }
 789         }
 790     }
 791
 792
 793     ovsdb_row_hash_destroy(&expected, true);
 794     ovsdb_row_hash_destroy(&actual, false);
 795     ovsdb_column_set_destroy(&columns);
 796     ovsdb_condition_destroy(&condition);
 797
 798     return error;
 799 }
 800
 801 static struct ovsdb_error *
 802 ovsdb_execute_comment(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 803                       struct json *result OVS_UNUSED)
 804 {
 805     const struct json *comment;
 806
 807     comment = ovsdb_parser_member(parser, "comment", OP_STRING);
 808     if (!comment) {
 809         return NULL;
 810     }
 811     ovsdb_txn_add_comment(x->txn, json_string(comment));
 812
 813     return NULL;
 814 }
 815
 816 static struct ovsdb_error *
 817 ovsdb_execute_assert(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 818                      struct json *result OVS_UNUSED)
 819 {
 820     const struct json *lock_name;
 821
 822     lock_name = ovsdb_parser_member(parser, "lock", OP_ID);
 823     if (!lock_name) {
 824         return NULL;
 825     }
 826
 827     if (x->session) {
 828         const struct ovsdb_lock_waiter *waiter;
 829
 830         waiter = ovsdb_session_get_lock_waiter(x->session,
 831                                                json_string(lock_name));
 832         if (waiter && ovsdb_lock_waiter_is_owner(waiter)) {
 833             return NULL;
 834         }
 835     }
 836
 837     return ovsdb_error("not owner", "Asserted lock %s not held.",
 838                        json_string(lock_name));
 839 }