/*
* Callback to RangeVarGetRelidExtended().
*
* Checks the following:
* - the relation specified is a table.
* - current user owns the table.
* - the table is not a system table.
*
* If any of these checks fails then an error is raised.
*/
static void
RangeVarCallbackForPolicy(const RangeVar *rv, Oid relid, Oid oldrelid,
void *arg)
{
HeapTuple tuple;
Form_pg_class classform;
char relkind;
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
if (!HeapTupleIsValid(tuple))
return;
classform = (Form_pg_class) GETSTRUCT(tuple);
relkind = classform->relkind;
/* Must own relation. */
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(get_rel_relkind(relid)), rv->relname);
/* No system table modifications unless explicitly allowed. */
if (!allowSystemTableMods && IsSystemClass(relid, classform))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
rv->relname)));
/* Relation type MUST be a table. */
if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table", rv->relname)));
ReleaseSysCache(tuple);
}
/*
* DefineQueryRewrite
* Create a rule
*
* This is essentially the same as DefineRule() except that the rule's
* action and qual have already been passed through parse analysis.
*/
ObjectAddress
DefineQueryRewrite(const char *rulename,
Oid event_relid,
Node *event_qual,
CmdType event_type,
bool is_instead,
bool replace,
List *action)
{
Relation event_relation;
ListCell *l;
Query *query;
bool RelisBecomingView = false;
Oid ruleId = InvalidOid;
ObjectAddress address;
/*
* If we are installing an ON SELECT rule, we had better grab
* AccessExclusiveLock to ensure no SELECTs are currently running on the
* event relation. For other types of rules, it would be sufficient to
* grab ShareRowExclusiveLock to lock out insert/update/delete actions and
* to ensure that we lock out current CREATE RULE statements; but because
* of race conditions in access to catalog entries, we can't do that yet.
*
* Note that this lock level should match the one used in DefineRule.
*/
event_relation = heap_open(event_relid, AccessExclusiveLock);
/*
* Verify relation is of a type that rules can sensibly be applied to.
* Internal callers can target materialized views, but transformRuleStmt()
* blocks them for users. Don't mention them in the error message.
*/
if (event_relation->rd_rel->relkind != RELKIND_RELATION &&
event_relation->rd_rel->relkind != RELKIND_MATVIEW &&
event_relation->rd_rel->relkind != RELKIND_VIEW &&
event_relation->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
RelationGetRelationName(event_relation))));
if (!allowSystemTableMods && IsSystemRelation(event_relation))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(event_relation))));
/*
* Check user has permission to apply rules to this relation.
*/
if (!pg_class_ownercheck(event_relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, get_relkind_objtype(event_relation->rd_rel->relkind),
RelationGetRelationName(event_relation));
/*
* No rule actions that modify OLD or NEW
*/
foreach(l, action)
{
query = lfirst_node(Query, l);
if (query->resultRelation == 0)
continue;
/* Don't be fooled by INSERT/SELECT */
if (query != getInsertSelectQuery(query, NULL))
continue;
if (query->resultRelation == PRS2_OLD_VARNO)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rule actions on OLD are not implemented"),
errhint("Use views or triggers instead.")));
if (query->resultRelation == PRS2_NEW_VARNO)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("rule actions on NEW are not implemented"),
errhint("Use triggers instead.")));
}
Datum
pgrowlocks(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
HeapScanDesc scan;
HeapTuple tuple;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
Datum result;
MyData *mydata;
Relation rel;
if (SRF_IS_FIRSTCALL())
{
text *relname;
RangeVar *relrv;
MemoryContext oldcontext;
AclResult aclresult;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
relname = PG_GETARG_TEXT_PP(0);
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a partitioned table",
RelationGetRelationName(rel)),
errdetail("Partitioned tables do not contain rows.")));
else if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
/*
* check permissions: must have SELECT on table or be in
* pg_stat_scan_tables
*/
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclresult = is_member_of_role(GetUserId(), DEFAULT_ROLE_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
RelationGetRelationName(rel));
scan = heap_beginscan(rel, GetActiveSnapshot(), 0, NULL);
mydata = palloc(sizeof(*mydata));
mydata->rel = rel;
mydata->scan = scan;
mydata->ncolumns = tupdesc->natts;
funcctx->user_fctx = mydata;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
attinmeta = funcctx->attinmeta;
mydata = (MyData *) funcctx->user_fctx;
scan = mydata->scan;
/* scan the relation */
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
HTSU_Result htsu;
TransactionId xmax;
uint16 infomask;
/* must hold a buffer lock to call HeapTupleSatisfiesUpdate */
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
htsu = HeapTupleSatisfiesUpdate(tuple,
GetCurrentCommandId(false),
scan->rs_cbuf);
xmax = HeapTupleHeaderGetRawXmax(tuple->t_data);
infomask = tuple->t_data->t_infomask;
/*
* A tuple is locked if HTSU returns BeingUpdated.
*/
if (htsu == HeapTupleBeingUpdated)
{
char **values;
values = (char **) palloc(mydata->ncolumns * sizeof(char *));
values[Atnum_tid] = (char *) DirectFunctionCall1(tidout,
PointerGetDatum(&tuple->t_self));
values[Atnum_xmax] = palloc(NCHARS * sizeof(char));
snprintf(values[Atnum_xmax], NCHARS, "%d", xmax);
if (infomask & HEAP_XMAX_IS_MULTI)
{
MultiXactMember *members;
int nmembers;
bool first = true;
bool allow_old;
values[Atnum_ismulti] = pstrdup("true");
allow_old = HEAP_LOCKED_UPGRADED(infomask);
nmembers = GetMultiXactIdMembers(xmax, &members, allow_old,
false);
if (nmembers == -1)
{
values[Atnum_xids] = "{0}";
values[Atnum_modes] = "{transient upgrade status}";
values[Atnum_pids] = "{0}";
}
else
{
int j;
values[Atnum_xids] = palloc(NCHARS * nmembers);
values[Atnum_modes] = palloc(NCHARS * nmembers);
values[Atnum_pids] = palloc(NCHARS * nmembers);
strcpy(values[Atnum_xids], "{");
strcpy(values[Atnum_modes], "{");
strcpy(values[Atnum_pids], "{");
for (j = 0; j < nmembers; j++)
{
char buf[NCHARS];
if (!first)
{
strcat(values[Atnum_xids], ",");
strcat(values[Atnum_modes], ",");
strcat(values[Atnum_pids], ",");
}
snprintf(buf, NCHARS, "%d", members[j].xid);
strcat(values[Atnum_xids], buf);
switch (members[j].status)
{
case MultiXactStatusUpdate:
snprintf(buf, NCHARS, "Update");
break;
case MultiXactStatusNoKeyUpdate:
snprintf(buf, NCHARS, "No Key Update");
break;
case MultiXactStatusForUpdate:
snprintf(buf, NCHARS, "For Update");
break;
case MultiXactStatusForNoKeyUpdate:
snprintf(buf, NCHARS, "For No Key Update");
break;
case MultiXactStatusForShare:
snprintf(buf, NCHARS, "Share");
break;
case MultiXactStatusForKeyShare:
snprintf(buf, NCHARS, "Key Share");
break;
}
strcat(values[Atnum_modes], buf);
snprintf(buf, NCHARS, "%d",
BackendXidGetPid(members[j].xid));
strcat(values[Atnum_pids], buf);
first = false;
}
strcat(values[Atnum_xids], "}");
strcat(values[Atnum_modes], "}");
strcat(values[Atnum_pids], "}");
}
}
else
{
values[Atnum_ismulti] = pstrdup("false");
values[Atnum_xids] = palloc(NCHARS * sizeof(char));
snprintf(values[Atnum_xids], NCHARS, "{%d}", xmax);
values[Atnum_modes] = palloc(NCHARS);
if (infomask & HEAP_XMAX_LOCK_ONLY)
{
if (HEAP_XMAX_IS_SHR_LOCKED(infomask))
snprintf(values[Atnum_modes], NCHARS, "{For Share}");
else if (HEAP_XMAX_IS_KEYSHR_LOCKED(infomask))
snprintf(values[Atnum_modes], NCHARS, "{For Key Share}");
else if (HEAP_XMAX_IS_EXCL_LOCKED(infomask))
{
if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)
snprintf(values[Atnum_modes], NCHARS, "{For Update}");
else
snprintf(values[Atnum_modes], NCHARS, "{For No Key Update}");
}
else
/* neither keyshare nor exclusive bit it set */
snprintf(values[Atnum_modes], NCHARS,
"{transient upgrade status}");
}
else
{
if (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)
snprintf(values[Atnum_modes], NCHARS, "{Update}");
else
snprintf(values[Atnum_modes], NCHARS, "{No Key Update}");
}
values[Atnum_pids] = palloc(NCHARS * sizeof(char));
snprintf(values[Atnum_pids], NCHARS, "{%d}",
BackendXidGetPid(xmax));
}
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
/* build a tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
/*
* no need to pfree what we allocated; it's on a short-lived
* memory context anyway
*/
SRF_RETURN_NEXT(funcctx, result);
}
else
{
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
}
}
heap_endscan(scan);
table_close(mydata->rel, AccessShareLock);
SRF_RETURN_DONE(funcctx);
}
