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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
msstruc.h
Abstract:
This module defines the data structures that make up the major internal part of the mailslot file system.
Author:
Manny Weiser (mannyw) 7-Jan-1991
Revision History:
--*/
#ifndef _MSSTRUC_
#define _MSSTRUC_
//
// The VCB record is the top record in the mailslot file system in-memory
// data structure. This structure must be allocated from non-paged pool
// and immediately follows (in memory) the Device object for the mailslot
// Structurally the layout of the data structure is as follows
//
// +------------+
// |MSDO |
// | |
// +------------+
// |Vcb |
// | |
// | |
// +------------+
// | ^
// | |
// | |
// v |
// +-------------+
// |RootDcb |
// | |<-+
// +-------------+ |
// : |
// : |
// : |
// v |
// +----------------+ +-------------------+
// |Fcb | |Ccb |
// | |<---| |
// | | | |
// +----------------+ +-------------------+
// ^ ^
// | |
// +---------+ +---------+
// |Server FO| |Client FO|
// | | | |
// +---------+ +---------+
//
//
// Where there is only one VCB for the entire mailslot file system, and
// it contains a single pointer to the root DCB for the file system. Off
// of the DCB is a queue of FCB's. There is one FCB for every mailslot.
// There are also two additional CCB types for the VCB and the root DCB,
// and notify records for the notify change operations.
//
// A newly initialized mailslot file system only contains the VCB and
// the root DCB. A new FCB is created when a new mailslot is created
// The file object for the creater (i.e., server end) points to the FCB
// and indicates that it is the server end. When a user does an open on
// the mailslot its file object is set to point to a CCB which belongs
// to the FCB.
//
// A file object with a null pointer to the FsContext field is a closed or
// disconnected mailslot.
//
//
// Each Fcb has a data queues for holding the outstanding
// read/write requests. The following type is used to determine
// if the data queue contains read requests, write requests, or is empty.
//
typedef enum _QUEUE_STATE { ReadEntries, WriteEntries, Empty} QUEUE_STATE;
//
// The node state.
//
// Currently only 2 states are defined. When a node is created it's state
// is NodeStateActive. When a cleanup IRP is processed, it set the node
// state of the corresponding node to NodeStateClosing. Only the close
// IRP can get processed on this node.
//
typedef enum _NODE_STATE { NodeStateActive, NodeStateClosing} NODE_STATE;
//
// The types of data entry there are. Each corresponds to an IRP
// that can be added to a data queue.
//
typedef enum _ENTRY_TYPE { Read, ReadMailslot, Write, WriteMailslot, Peek} ENTRY_TYPE;
//
// The data queue is a structure that contains the queue state, quota
// information, and the list head. The quota information is used to
// maintain mailslot quota.
//
typedef struct _DATA_QUEUE {
//
// The current state of what is contained in this data queue,
// how many bytes of read/write data there are, and how many individual
// requests there are in the queue that contain data (includes
// close or flush requests).
//
QUEUE_STATE QueueState; ULONG BytesInQueue; ULONG EntriesInQueue;
//
// The following two fields denote who much quota was reserved for
// this mailslot and how much we've used up. This is only
// the creator quota and not the user quota.
//
ULONG Quota; ULONG QuotaUsed;
//
// The size of the largest message that can be written to
// this data queue.
//
ULONG MaximumMessageSize;
//
// The queue of data entries.
//
LIST_ENTRY DataEntryList;
} DATA_QUEUE, *PDATA_QUEUE;
//
// The following type is used to denote where we got the memory for the
// data entry and possibly the data buffer. We either got the memory
// from the mailslot quota, the user quota, or it is part of the next IRP
// stack location.
//
typedef enum _FROM { MailslotQuota, UserQuota, InIrp} FROM;
//
// Each entry in the data queue is a data entry. Processing an IRP
// has the potential of creating and inserting a new data entry. If the
// memory for the entry is taken from the IRP we use the current stack
// location.
//
typedef struct _DATA_ENTRY {
//
// Where the data buffer came from
//
UCHAR From; CHAR Spare1; USHORT Spare2;
//
// The following field is how we connect into the queue of data entries
//
LIST_ENTRY ListEntry;
//
// The following field indicates if we still have an IRP associated
// with this data entry that need to be completed when the remove
// the data entry. Note that if From is InIrp that this IRP field
// must not be null.
//
PIRP Irp;
//
// The following two fields describe the size and location of the data
// buffer described by this entry. These fields are only used if the
// type is buffered, and are ignored otherwise.
//
ULONG DataSize; PVOID DataPointer;
//
// Used for read data entries only. A pointer to the work context
// of the time out.
//
struct _WORK_CONTEXT *TimeoutWorkContext;
} DATA_ENTRY, *PDATA_ENTRY;
//
// The node header is used to manage standard nodes within MSFS.
//
typedef struct _NODE_HEADER {
NODE_TYPE_CODE NodeTypeCode; // The node type
NODE_BYTE_SIZE NodeByteSize; // The size of the node
NODE_STATE NodeState; // The current node state
ULONG ReferenceCount; // Number of active references to the node
} NODE_HEADER, *PNODE_HEADER;
typedef struct _VCB {
NODE_HEADER Header;
//
// The filesystem name
//
UNICODE_STRING FileSystemName;
//
// The time we created the volume
//
LARGE_INTEGER CreationTime;
//
// A pointer to the root DCB for this volume
//
struct _FCB *RootDcb;
//
// A prefix table that is used for quick, prefix directed, lookup of
// FCBs/DCBs that are part of this volume
//
UNICODE_PREFIX_TABLE PrefixTable;
//
// A resource variable to control access to the volume specific data
// structures
//
ERESOURCE Resource;
//
// The following field is used to check share access people who want
// to open the mailslot driver
//
SHARE_ACCESS ShareAccess;
} VCB, *PVCB;
//
// The Mailslot Device Object is an I/O system device object with
// additional workqueue parameters appended to the end. There is only
// one of these records created for the entire system during system
// initialization. The workqueue is used by the FSD to post requests to
// the filesystem.
//
typedef struct _MSFS_DEVICE_OBJECT {
DEVICE_OBJECT DeviceObject;
//
// This is the file system specific volume control block.
//
VCB Vcb;
} MSFS_DEVICE_OBJECT, *PMSFS_DEVICE_OBJECT;
//
// The Fcb/Dcb record corresponds to every opened mailslot and directory,
// and to every directory on an opened path.
//
typedef struct _FCB {
//
// Header.NodeTypeCode of this record (must be MSFS_NTC_FCB, or
// MSFS_NTC_ROOT_DCB)
//
NODE_HEADER Header;
//
// The links for the queue of all fcbs for a specific DCB off of
// Dcb.ParentDcbQueue. For the root directory this queue is empty.
//
LIST_ENTRY ParentDcbLinks;
//
// A pointer to the Dcb that is the parent directory containing
// this FCB. If this record itself is the root dcb then this field
// is null.
//
struct _FCB *ParentDcb;
//
// A pointer to the VCB containing this FCB.
//
PVCB Vcb;
//
// Back pointer to the server's file object.
//
PFILE_OBJECT FileObject;
//
// A pointer to the security descriptor for this mailslot.
//
PSECURITY_DESCRIPTOR SecurityDescriptor;
//
// The following union is cased off of the node type code for the FCB.
// is a seperate case for the directory versus file FCBs.
//
union {
//
// A Directory Control Block (DCB)
//
struct {
//
// A queue of the notify IRPs that will be completed when any
// change is made to a file in the directory. Queued using
// the Tail.Overlay.ListEntry of the IRP.
//
LIST_ENTRY NotifyFullQueue;
//
// A queue of the notify IRPs that will be completed only if a
// file is added, deleted, or renamed in the directory. Queued
// using the Tail.Overlay.ListEntry of the IRP.
//
LIST_ENTRY NotifyPartialQueue;
//
// A queue of all the FCBs/DCBs that are opened under this
// DCB.
//
LIST_ENTRY ParentDcbQueue;
//
// Spinlock to protect the queues above that contain cancelable IRPs. We can't
// synchronize with a resource because IoCancelIrp can be called at DISPATCH_LEVEL.
//
KSPIN_LOCK SpinLock; } Dcb;
//
// A File Control Block (FCB)
//
struct {
//
// The following field is a queue head for a list of CCBs
// that are opened under us.
//
LIST_ENTRY CcbQueue;
//
// The default read timeout. This is always a relative value.
//
LARGE_INTEGER ReadTimeout;
//
// File timestamps.
//
LARGE_INTEGER CreationTime; LARGE_INTEGER LastModificationTime; LARGE_INTEGER LastAccessTime; LARGE_INTEGER LastChangeTime;
} Fcb;
} Specific;
//
// The following field is used to check share access for
// clients that want to open the file/directory.
//
SHARE_ACCESS ShareAccess;
//
// The following field is the fully qualified file name for this FCB/DCB
// starting from the root of the volume, and last file name in the
// fully qualified name.
//
UNICODE_STRING FullFileName; UNICODE_STRING LastFileName;
//
// The following field contains a prefix table entry that is used when
// searching a volume for a name (or longest matching prefix)
//
UNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry;
//
// The following field is used to remember the process that created this
// mailslot. It is needed to allocate quota and return quota.
//
PEPROCESS CreatorProcess;
//
// The following data queue is used to contain the buffered information
// for the mailslot.
//
DATA_QUEUE DataQueue;
//
// A resource variable to control access to the File specific data
// structures
//
ERESOURCE Resource;
} FCB, DCB, ROOT_DCB, *PFCB, *PDCB, *PROOT_DCB;
//
// The CCB record is allocated for every cliennt side open of a mailslot.
//
typedef struct _CCB {
//
// Header.NodeTypeCode of this record (must be MSFS_NTC_CCB).
//
NODE_HEADER Header;
//
// The following field is a list entry for the list of ccb that we
// are a member of.
//
LIST_ENTRY CcbLinks;
//
// A pointer to the FCB, or VCB that we are tied to
//
PFCB Fcb;
//
// Pointers to the file object of the client has opened this file.
//
PFILE_OBJECT FileObject;
//
// A resource to control access to the CCB.
//
ERESOURCE Resource;
} CCB, *PCCB;
//
// The root DCB CCB record is allocated for every opened instance of the
// root dcb. This record is pointed at by FsContext2.
//
typedef struct _ROOT_DCB_CCB {
//
// Header.NodeTypeCode of this record (must be MSFS_NTC_ROOT_DCB_CCB).
//
NODE_HEADER Header;
//
// A pointer to the VCB containing this CCB.
//
PVCB Vcb;
//
// Pointer to the DCB for this CCB
//
PROOT_DCB Dcb;
//
// The following field is a count of the last index returned
// by query directory.
//
ULONG IndexOfLastCcbReturned;
//
// The following string is used as a query template for directory
// query operations
//
PUNICODE_STRING QueryTemplate;
} ROOT_DCB_CCB, *PROOT_DCB_CCB;
//
// A work context contains the information needed to do read timeouts.
//
typedef struct _WORK_CONTEXT {
//
// Pointer to unload safe work item.
//
PIO_WORKITEM WorkItem;
//
// A pointer to the IRP for this operation.
//
PIRP Irp;
//
// A referenced pointer to the FCB that will process this operation.
//
PFCB Fcb;
//
// A timer and dpc tourine to accomplish the timeout.
//
KTIMER Timer;
KDPC Dpc;
} WORK_CONTEXT, *PWORK_CONTEXT;
#endif // _MSSTRUC_
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