Function RangeVarCallbackForLockTable

src/backend/commands/lockcmds.c:94–131

* Before acquiring a table lock on the named table, check whether we have * permission to do so. */

 * permission to do so.
 */
static void
RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
							 void *arg)
{
	LOCKMODE	lockmode = *(LOCKMODE *) arg;
	char		relkind;
	AclResult	aclresult;

	if (!OidIsValid(relid))
		return;					/* doesn't exist, so no permissions check */
	relkind = get_rel_relkind(relid);
	if (!relkind)
		return;					/* woops, concurrently dropped; no permissions
								 * check */

	/* Currently, we only allow plain tables or views to be locked */
	if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
		relkind != RELKIND_VIEW && relkind != RELKIND_DIRECTORY_TABLE)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is not a table, directory table or view",
						rv->relname)));

#if 0 /* Upstream code not applicable to GPDB */
	/*
	 * Make note if a temporary relation has been accessed in this
	 * transaction.
	 */
	relpersistence = get_rel_persistence(relid);
	if (relpersistence == RELPERSISTENCE_TEMP)
		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
#endif

	/* Check permissions. */
	aclresult = LockTableAclCheck(relid, lockmode, GetUserId());
	if (aclresult != ACLCHECK_OK)
		aclcheck_error(aclresult, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
}

/*
 * Apply LOCK TABLE recursively over an inheritance tree