RX_CONTEXT数据结构

//留着以备查询之用 来自WinDDK\6000\inc\ddk\rxcontx.h

typedef struct _RX_CONTEXT {
    
    //
    //  the node type, size and reference count, aka standard header
    // 

    NODE_TYPE_CODE NodeTypeCode;
    NODE_BYTE_SIZE NodeByteSize;
    __volatile ULONG ReferenceCount;

    //
    //  the list entry to wire the context to the list of active contexts
    //

    LIST_ENTRY ContextListEntry;

    //
    //  Major and minor function of the IRP associated with the context
    //

    UCHAR MajorFunction;
    UCHAR MinorFunction;

    //
    //  this is similar to the same field in Irps; it
    //  allows callback routines for async operations
    //  to know whether to do asynchronous work or not
    //

    BOOLEAN PendingReturned;

    //
    //  indicates if the associated request is to be posted to a RDBSS worker thread.
    //

    BOOLEAN PostRequest;

    //
    //  Originating Device (required for workque algorithms)
    //  not currently used but could be used for local minis
    //

    PDEVICE_OBJECT RealDevice;

    //
    //  ptr to the originating Irp
    //

    PIRP CurrentIrp;

    //
    //  ptr to the IRP stack location
    //

    PIO_STACK_LOCATION CurrentIrpSp;

    //
    //  ptr to the FCB and FOBX, derived from the context pointers in the
    //  file object associated with the IRP
    //

    PMRX_FCB pFcb;
    PMRX_FOBX pFobx;
    PMRX_SRV_OPEN pRelevantSrvOpen;
    PNON_PAGED_FCB NonPagedFcb;

    //
    //  device object calldown (not irpsp.....)
    //

    PRDBSS_DEVICE_OBJECT RxDeviceObject;

    //
    //  The original thread in which the request was initiated and the last
    //  thread in which some processing associated with the context was done
    //

    PETHREAD OriginalThread;
    PETHREAD LastExecutionThread;

    __volatile PVOID LockManagerContext;

    //
    //  One word of the context is given to rdbss for dbg information
    //

    PVOID RdbssDbgExtension;

    RX_SCAVENGER_ENTRY ScavengerEntry;

    //
    //  global serial number for this operation
    //

    ULONG SerialNumber;

    //
    //  used by minirdrs to see if multiple calls are part
    //  of the same larger operation and (therefore) more cacheable
    //

    ULONG FobxSerialNumber;

    ULONG Flags;

    BOOLEAN FcbResourceAcquired;
    BOOLEAN FcbPagingIoResourceAcquired;
    UCHAR MustSucceedDescriptorNumber;

    //
    //  mostly you want the individual components...sometimes it's nice as a pair
    //  used to record the status when you can't just return it; e.g., when
    //  RXSTATUS is not an appropriate return type or if the consumer of the
    //  status didn't call directly (lowiocompletions). minirdrs will not need
    //  to set the information directly
    //

    union {
        struct {
            union {
                NTSTATUS StoredStatus;
                PVOID StoredStatusAlignment;
            };
            ULONG_PTR InformationToReturn;
        };
        IO_STATUS_BLOCK IoStatusBlock;
    };

    //
    //  the context fields provided for use by the mini redirectors
    //  this is defined as a union to force longlong alignment
    //

    union {
        ULONGLONG ForceLonglongAligmentDummyField;
        PVOID MRxContext[MRX_CONTEXT_FIELD_COUNT];
    };

    //
    //  The following field is included to fix the problem related to write only
    //  opens. This introduces a new field for the mini redirector to squirrel
    //  some state. This is redundant and should be removed after Windows 2000.
    //  Having a unique field reduces the impact of the change that we are making
    //  to the specific code path. It will be ideal to use one of the MRXContext
    //  fields defined above
    //

    PVOID WriteOnlyOpenRetryContext;

    //
    //  the cancellation routine to be invoked, set by the mini redirector
    //

    PMRX_CALLDOWN MRxCancelRoutine;

    //
    //  private dispatch, if any. used in fspdisp
    //

    PRX_DISPATCH ResumeRoutine;

    //
    //  for posting to worker threads
    //  the minirdr can use this for posting within the minirdr
    //  a potential problem can arise if the minirdr relies on this both
    //  for queueing async stuff and for queueing cancel stuff
    //

    //
    //  The OverflowListEntry is used for queueing items to the overflow queue.
    //  This is seperate now to allow us to distinguish between an item in the overflow
    //  queue and one in the active work queue (for cancellation logic)
    //

    RX_WORK_QUEUE_ITEM WorkQueueItem;
    LIST_ENTRY OverflowListEntry;

    //
    //  this event is used for synchronous operations
    //  that have to i/f with an underlying async service. it can be used
    //  by the minirdr with the following provisions:
    //      1) on entering the minirdr through lowio, it is set to the
    //         nonsignaled state (but a wise user will reset it before using
    //         it....particularly if it's used multiple times.
    //      2) if you are returning STATUS_PENDING on a sync operation, you must
    //         return with it set to the nonsignaled state; that is, either
    //         you don't use it or you reset it in this case
    //

    KEVENT SyncEvent;

    //
    //  this is a list head of operations that are to be released on completion
    //

    LIST_ENTRY BlockedOperations;

    //
    //  this is the mutex that controls serialization of the blocked operations
    //

    PFAST_MUTEX BlockedOpsMutex;

    //
    //  these links are used to serialize pipe operations on a
    //  per-file-object basis AND FOR LOTS OF OTHER STUFF
    //

    LIST_ENTRY RxContextSerializationQLinks;

    union {
        struct {
            union {
                FS_INFORMATION_CLASS FsInformationClass;
                FILE_INFORMATION_CLASS FileInformationClass;
            };
            PVOID Buffer;
            union {
                LONG Length;
                LONG LengthRemaining;
            };
            BOOLEAN ReplaceIfExists;
            BOOLEAN AdvanceOnly;
        } Info;

        struct {
            UNICODE_STRING SuppliedPathName;
            NET_ROOT_TYPE NetRootType;
            PIO_SECURITY_CONTEXT pSecurityContext;
        } PrefixClaim;
    };

    //
    //  THIS UNION MUST BE LAST....AT SOME POINT, WE MAY START ALLOCATING
    //  SMALLER PER OPERATION!
    //

    union{
        struct {
            NT_CREATE_PARAMETERS NtCreateParameters; //  a copy of the createparameters
            ULONG ReturnedCreateInformation;
            PWCH CanonicalNameBuffer;  // if the canonical name is larger than available buffer
            PRX_PREFIX_ENTRY NetNamePrefixEntry;   // the entry returned by the lookup....for dereferencing

            PMRX_SRV_CALL pSrvCall;              // Server Call being used
            PMRX_NET_ROOT pNetRoot;              // Net Root being used
            PMRX_V_NET_ROOT pVNetRoot;             // Virtual Net Root
            //PMRX_SRV_OPEN        pSrvOpen;              // Server Open

            PVOID EaBuffer;
            ULONG EaLength;

            ULONG SdLength;

            ULONG PipeType;
            ULONG PipeReadMode;
            ULONG PipeCompletionMode;

            USHORT Flags;
            NET_ROOT_TYPE Type;                 // Type of Net Root(Pipe/File/Mailslot..)
            UCHAR         RdrFlags;             // Flags for use by the RDR while processing the request.

            BOOLEAN FcbAcquired;
            BOOLEAN TryForScavengingOnSharingViolation;
            BOOLEAN ScavengingAlreadyTried;

            BOOLEAN ThisIsATreeConnectOpen;
            BOOLEAN TreeConnectOpenDeferred;
            UNICODE_STRING TransportName;
            UNICODE_STRING UserName;
            UNICODE_STRING Password;
            UNICODE_STRING UserDomainName;
        } Create;
        struct {
            ULONG FileIndex;
            BOOLEAN RestartScan;
            BOOLEAN ReturnSingleEntry;
            BOOLEAN IndexSpecified;
            BOOLEAN InitialQuery;
        } QueryDirectory;
        struct {
            PMRX_V_NET_ROOT pVNetRoot;
        } NotifyChangeDirectory;
        struct {
            PUCHAR UserEaList;
            ULONG UserEaListLength;
            ULONG UserEaIndex;
            BOOLEAN RestartScan;
            BOOLEAN ReturnSingleEntry;
            BOOLEAN IndexSpecified;
        } QueryEa;
        struct {
            SECURITY_INFORMATION SecurityInformation;
            ULONG Length;
        } QuerySecurity;
        struct {
            SECURITY_INFORMATION SecurityInformation;
            PSECURITY_DESCRIPTOR SecurityDescriptor;
        } SetSecurity;
        struct {
            ULONG Length;
            PSID StartSid;
            PFILE_GET_QUOTA_INFORMATION SidList;
            ULONG SidListLength;
            BOOLEAN RestartScan;
            BOOLEAN ReturnSingleEntry;
            BOOLEAN IndexSpecified;
        } QueryQuota;
        struct {
            ULONG Length;

        } SetQuota;
        struct {
            PV_NET_ROOT VNetRoot;
            PSRV_CALL SrvCall;
            PNET_ROOT NetRoot;
        } DosVolumeFunction;
        struct {
            ULONG FlagsForLowIo;
            LOWIO_CONTEXT LowIoContext;        //  the LOWIO parameters
        }; //  no name here....
        LUID FsdUid;
    } ;

    //
    //  CODE.IMPROVEMENT remove this to wrapperdbgprivates
    //

    PWCH AlsoCanonicalNameBuffer;  //  if the canonical name is larger than available buffer
    PUNICODE_STRING LoudCompletionString;

#ifdef RDBSS_TRACKER
    __volatile LONG AcquireReleaseFcbTrackerX;
    __volatile ULONG TrackerHistoryPointer;
    RX_FCBTRACKER_CALLINFO TrackerHistory[RDBSS_TRACKER_HISTORY_SIZE];
#endif

#if DBG
    ULONG ShadowCritOwner;
#endif

} RX_CONTEXT, *PRX_CONTEXT;