citus/src/backend/distributed/commands/foreign_data_wrapper.c

149 lines
3.9 KiB
C

/*-------------------------------------------------------------------------
*
* foreign_data_wrapper.c
* Commands for FOREIGN DATA WRAPPER statements.
*
* Copyright (c) Citus Data, Inc.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_foreign_data_wrapper.h"
#include "distributed/commands/utility_hook.h"
#include "distributed/commands.h"
#include "distributed/deparser.h"
#include "distributed/listutils.h"
#include "distributed/metadata_sync.h"
#include "distributed/metadata/distobject.h"
#include "foreign/foreign.h"
#include "nodes/makefuncs.h"
#include "nodes/parsenodes.h"
#include "utils/syscache.h"
static bool NameListHasFDWOwnedByDistributedExtension(List *FDWNames);
static ObjectAddress GetObjectAddressByFDWName(char *FDWName, bool missing_ok);
/*
* PreprocessGrantOnFDWStmt is executed before the statement is applied to the
* local postgres instance.
*
* In this stage we can prepare the commands that need to be run on all workers to grant
* on foreign data wrappers.
*/
List *
PreprocessGrantOnFDWStmt(Node *node, const char *queryString,
ProcessUtilityContext processUtilityContext)
{
GrantStmt *stmt = castNode(GrantStmt, node);
Assert(stmt->objtype == OBJECT_FDW);
if (!NameListHasFDWOwnedByDistributedExtension(stmt->objects))
{
/*
* We propagate granted privileges on a FDW only if it belongs to a distributed
* extension. For now, we skip for custom FDWs, as most of the users prefer
* extension FDWs.
*/
return NIL;
}
if (list_length(stmt->objects) > 1)
{
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot grant on FDW with other FDWs"),
errhint("Try granting on each object in separate commands")));
}
if (!ShouldPropagate())
{
return NIL;
}
EnsureCoordinator();
/* the code-path only supports a single object */
Assert(list_length(stmt->objects) == 1);
char *sql = DeparseTreeNode((Node *) stmt);
List *commands = list_make3(DISABLE_DDL_PROPAGATION,
(void *) sql,
ENABLE_DDL_PROPAGATION);
return NodeDDLTaskList(NON_COORDINATOR_NODES, commands);
}
/*
* NameListHasFDWOwnedByDistributedExtension takes a namelist of FDWs and returns true
* if at least one of them depends on a distributed extension. Returns false otherwise.
*/
static bool
NameListHasFDWOwnedByDistributedExtension(List *FDWNames)
{
String *FDWValue = NULL;
foreach_ptr(FDWValue, FDWNames)
{
/* captures the extension address during lookup */
ObjectAddress *extensionAddress = palloc0(sizeof(ObjectAddress));
ObjectAddress FDWAddress = GetObjectAddressByFDWName(strVal(FDWValue), false);
ObjectAddress *copyFDWAddress = palloc0(sizeof(ObjectAddress));
*copyFDWAddress = FDWAddress;
if (IsAnyObjectAddressOwnedByExtension(list_make1(copyFDWAddress),
extensionAddress))
{
if (IsAnyObjectDistributed(list_make1(extensionAddress)))
{
return true;
}
}
}
return false;
}
/*
* GetObjectAddressByFDWName takes a FDW name and returns the object address.
*/
static ObjectAddress
GetObjectAddressByFDWName(char *FDWName, bool missing_ok)
{
ForeignDataWrapper *FDW = GetForeignDataWrapperByName(FDWName, missing_ok);
Oid FDWId = FDW->fdwid;
ObjectAddress address = { 0 };
ObjectAddressSet(address, ForeignDataWrapperRelationId, FDWId);
return address;
}
/*
* GetPrivilegesForFDW takes a FDW object id and returns the privileges granted
* on that FDW as a Acl object. Returns NULL if there is no privilege granted.
*/
Acl *
GetPrivilegesForFDW(Oid FDWOid)
{
HeapTuple fdwtup = SearchSysCache1(FOREIGNDATAWRAPPEROID, ObjectIdGetDatum(FDWOid));
bool isNull = true;
Datum aclDatum = SysCacheGetAttr(FOREIGNDATAWRAPPEROID, fdwtup,
Anum_pg_foreign_data_wrapper_fdwacl, &isNull);
if (isNull)
{
ReleaseSysCache(fdwtup);
return NULL;
}
Acl *aclEntry = DatumGetAclPCopy(aclDatum);
ReleaseSysCache(fdwtup);
return aclEntry;
}