Leaked source code of windows server 2003
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166 lines
5.3 KiB

1) OUT params are not guaranteed to be initialized except in
the case of "Num of handles returned in an Enumeration" -
- like NumDests in RtmGetEnumDests etc.
2) Callbacks to entities - there are certain restrictions on
what Rtm calls can be used in the context of an RTM event
callback -
Entity Registration/De-registration callbacks:
RtmRegisterEntity
RtmDeregisterEntity
RtmGetRegdEntities
RtmGetInstances
RtmGetInstanceInfo
RtmGetAddrFamilyInfo
Route Timed-out callback:
Can call anything (as of now)
Change Notification callback:
RtmRegisterForChangeNotification
RtmDeregisterForChangeNotification
3) If RTM has to take care of the fact that no ops should be
allowed after deregistration -
//------------------------------------------------------
Code in RTMDeregisterEntity -
/*-----------------------------------------------------
This function marks the entity as deregistered thereby
preventing this entity from making any more operations.
It also waits until all pending operations on (or) by
this entity are completed before it start cleaning up
the state of the entity being deregistered.
If other entities have handles open on objects of this
entity, then this memory is reclaimed when these handles
are released.
Note that if this entity has handles open on objects
(routes and nexthops) owned by another entity, then we
have a case of a memory leak.
------------------------------------------------------*/
//
// Mark entity as deregistered to prevent more ops
//
try
{
Entity = GET_POINTER_FROM_HANDLE(RtmRegHandle);
#if DBG_HDL
if (Entity->ObjectHeader.TypeSign != ENTITY_ALLOC)
{
return ERROR_INVALID_HANDLE;
}
#endif
// Block all new ops by flagging a deregister
OldState = InterlockedExchangeAdd(&Entity->State,
ENTITY_STATE_DEREGISTERED);
if (OldState >= ENTITY_STATE_DEREGISTERED)
{
// We have already de-registered here
InterlockedExchangeAdd(&Entity->State,
(-1) * ENTITY_STATE_DEREGISTERED);
return ERROR_INVALID_HANDLE;
}
}
except(EXCEPTION_EXECUTE_HANDLER)
{
return ERROR_INVALID_HANDLE;
}
//
// Block while waiting for active ops to finish
//
while (Entity->State != ENTITY_STATE_DEREGISTERED)
{
Sleep(0);
}
and
Code for validating handle in other functions -
try
{
Entity = GET_POINTER_FROM_HANDLE(RtmRegHandle);
#if DBG_HDL
if (Entity->ObjectHeader.TypeSign != ENTITY_ALLOC)
{
return ERROR_INVALID_HANDLE;
}
#endif
if (InterlockedIncrement(&Entity->State) >= ENTITY_STATE_DEREGISTERED)
{
// We have already de-registered here
InterlockedDecrement(&Entity->State);
return ERROR_INVALID_HANDLE;
}
}
except(EXCEPTION_EXECUTE_HANDLER)
{
return ERROR_INVALID_HANDLE;
}
//------------------------------------------------------
4) In case you wanted to use Interlocked Ops on lists -
//
// Single Link List manipulation using Interlocked Ops
//
#define InterlockedPushEntryList(ListHead, Entry) \
while (TRUE) \
{ \
(Entry)->Next = (ListHead)->Next; \
if (InterlockedCompareExchangePointer(&((ListHead)->Next),\
(Entry), \
(Entry)->Next) \
== (Entry)->Next) \
{ \
break; \
} \
} \
#define InterlockedPopEntryList(ListHead, Entry) \
while (TRUE) \
{ \
Entry = (ListHead)->Next; \
if (Entry == NULL) \
{ \
break; \
} \
\
if (InterlockedCompareExchangePointer(&((ListHead)->Next),\
((Entry)->Next), \
(Entry) \
!= (Entry)) \
{ \
continue; \
} \
}