/*
* sepgsql_subxact_callback
*
* A callback routine of sub-transaction start/abort/commit. Releases all
* security labels that are set within the sub-transaction that is aborted.
*/
static void
sepgsql_subxact_callback(SubXactEvent event, SubTransactionId mySubid,
SubTransactionId parentSubid, void *arg)
{
ListCell *cell;
ListCell *prev;
ListCell *next;
if (event == SUBXACT_EVENT_ABORT_SUB)
{
prev = NULL;
for (cell = list_head(client_label_pending); cell; cell = next)
{
pending_label *plabel = lfirst(cell);
next = lnext(cell);
if (plabel->subid == mySubid)
client_label_pending
= list_delete_cell(client_label_pending, cell, prev);
else
prev = cell;
}
}
}
/*
* Delete the first element of the list.
*
* This is useful to replace the Lisp-y code "list = lnext(list);" in cases
* where the intent is to alter the list rather than just traverse it.
* Beware that the removed cell is freed, whereas the lnext() coding leaves
* the original list head intact if there's another pointer to it.
*/
List *
list_delete_first(List *list)
{
if (list == NIL)
return NIL; /* would an error be better? */
return list_delete_cell(list, list_head(list), NULL);
}
/*
* Delete the first element of the list.
*
* This is useful to replace the Lisp-y code "list = lnext(list);" in cases
* where the intent is to alter the list rather than just traverse it.
* Beware that the removed cell is freed, whereas the lnext() coding leaves
* the original list head intact if there's another pointer to it.
*/
List *
list_delete_first(List *list)
{
check_list_invariants(list);
if (list == NIL)
return NIL; /* would an error be better? */
return list_delete_cell(list, list_head(list), NULL);
}
/* As above, but use simple pointer equality */
List *
list_delete_ptr(List *list, void *datum)
{
ListCell *cell;
ListCell *prev;
Assert(IsPointerList(list));
prev = NULL;
foreach(cell, list)
{
if (lfirst(cell) == datum)
return list_delete_cell(list, cell, prev);
prev = cell;
}
/* Didn't find a match: return the list unmodified */
return list;
}
/* As above, but for OIDs */
List *
list_delete_oid(List *list, Oid datum)
{
ListCell *cell;
ListCell *prev;
Assert(IsOidList(list));
check_list_invariants(list);
prev = NULL;
foreach(cell, list)
{
if (lfirst_oid(cell) == datum)
return list_delete_cell(list, cell, prev);
prev = cell;
}
/* Didn't find a match: return the list unmodified */
return list;
}
/*
* Delete the first cell in list that matches datum, if any.
* Equality is determined via equal().
*/
List *
list_delete(List *list, void *datum)
{
ListCell *cell;
ListCell *prev;
Assert(IsPointerList(list));
check_list_invariants(list);
prev = NULL;
foreach(cell, list)
{
if (equal(lfirst(cell), datum))
return list_delete_cell(list, cell, prev);
prev = cell;
}
/* Didn't find a match: return the list unmodified */
return list;
}
/*
* Reclaim caches recently unreferenced
*/
static void
sepgsql_avc_reclaim(void)
{
ListCell *cell;
ListCell *next;
ListCell *prev;
int index;
while (avc_num_caches >= avc_threshold - AVC_NUM_RECLAIM)
{
index = avc_lru_hint;
prev = NULL;
for (cell = list_head(avc_slots[index]); cell; cell = next)
{
avc_cache *cache = lfirst(cell);
next = lnext(cell);
if (!cache->hot_cache)
{
avc_slots[index]
= list_delete_cell(avc_slots[index], cell, prev);
pfree(cache->scontext);
pfree(cache->tcontext);
if (cache->ncontext)
pfree(cache->ncontext);
pfree(cache);
avc_num_caches--;
}
else
{
cache->hot_cache = false;
prev = cell;
}
}
avc_lru_hint = (avc_lru_hint + 1) % AVC_NUM_SLOTS;
}
}
/*
* StandbyReleaseLocksMany
* Release standby locks held by XIDs < removeXid
*
* If keepPreparedXacts is true, keep prepared transactions even if
* they're older than removeXid
*/
static void
StandbyReleaseLocksMany(TransactionId removeXid, bool keepPreparedXacts)
{
ListCell *cell,
*prev,
*next;
LOCKTAG locktag;
/*
* Release all matching locks.
*/
prev = NULL;
for (cell = list_head(RecoveryLockList); cell; cell = next)
{
xl_standby_lock *lock = (xl_standby_lock *) lfirst(cell);
next = lnext(cell);
if (!TransactionIdIsValid(removeXid) || TransactionIdPrecedes(lock->xid, removeXid))
{
if (keepPreparedXacts && StandbyTransactionIdIsPrepared(lock->xid))
continue;
elog(trace_recovery(DEBUG4),
"releasing recovery lock: xid %u db %u rel %u",
lock->xid, lock->dbOid, lock->relOid);
SET_LOCKTAG_RELATION(locktag, lock->dbOid, lock->relOid);
if (!LockRelease(&locktag, AccessExclusiveLock, true))
elog(LOG,
"RecoveryLockList contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
lock->xid, lock->dbOid, lock->relOid);
RecoveryLockList = list_delete_cell(RecoveryLockList, cell, prev);
pfree(lock);
}
else
prev = cell;
}
}
static void
StandbyReleaseLocks(TransactionId xid)
{
ListCell *cell,
*prev,
*next;
/*
* Release all matching locks and remove them from list
*/
prev = NULL;
for (cell = list_head(RecoveryLockList); cell; cell = next)
{
xl_standby_lock *lock = (xl_standby_lock *) lfirst(cell);
next = lnext(cell);
if (!TransactionIdIsValid(xid) || lock->xid == xid)
{
LOCKTAG locktag;
elog(trace_recovery(DEBUG4),
"releasing recovery lock: xid %u db %u rel %u",
lock->xid, lock->dbOid, lock->relOid);
SET_LOCKTAG_RELATION(locktag, lock->dbOid, lock->relOid);
if (!LockRelease(&locktag, AccessExclusiveLock, true))
elog(LOG,
"RecoveryLockList contains entry for lock no longer recorded by lock manager: xid %u database %u relation %u",
lock->xid, lock->dbOid, lock->relOid);
RecoveryLockList = list_delete_cell(RecoveryLockList, cell, prev);
pfree(lock);
}
else
prev = cell;
}
}
