[转]C/C++ 实现文件透明加解密

今日遇见一个开超市的朋友，真没想到在高校开超市一个月可以达到月净利润50K，相比起我们程序员的工资，真是不可同日而语，这个世道啊，真是做程序员不如经商开超市， 我们高科技的从业者，真是造原子弹不如卖茶叶蛋。

请见代码详细注释

//  修复涉及后视列表的Win2K兼容性 //  Fixes Win2K compatibility regarding lookaside lists. //

#ifndef _WIN2K_COMPAT_SLIST_USAGE // Add content(增加内容) #define _WIN2K_COMPAT_SLIST_USAGE #endif

#include "ntifs.h" #include "ntdddisk.h"

// // 在代码中开启这些警告 // Enable these warnings in the code. //

#pragma warning(error:4100) // Unreferenced formal parameter 未被引用的正式参数 #pragma warning(error:4101) // Unreferenced local variable  未被引用的局部参数

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //     Macro and Structure Definitions // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

// // VERSION NOTE: // // 下面的宏在Windows XP及以后ＯＳ中的NTIFS.H中被定义，如果我们在Windows 2000环境下编译加上这些定义 // The following useful macros are defined in NTIFS.H in Windows XP and later. // We will define them locally if we are building for the Windows 2000 // environment. //

#if WINVER == 0x0500

// // 用于测试、设置、清除标志 // These macros are used to test, set and clear flags respectively //

// 打开标志 #ifndef FlagOn #define FlagOn(_F, _SF)   ((_F) & (_SF)) #endif

// 测试标志是否打开 #ifndef BooleanFlagOn #define BooleanFlagOn(F, SF) ((BOOLEAN) (((F) & (SF)) != 0)) #endif

// 设置标志 #ifndef SetFlag #define SetFlag(_F, _SF)  ((_F) |= (_SF)) #endif

// 清除标志 #ifndef ClearFlag #define ClearFlag(_F, _SF)  ((_F) &= ~(_SF)) #endif

#define RtlInitEmptyUnicodeString(_ucStr, _buf, _bufSize) /  ((_ucStr)->Buffer = (_buf), /   (_ucStr)->Length = 0, /   (_ucStr)->MaximumLength = (USHORT)(_bufSize))

#ifndef min #define min(a, b) (((a) < (b)) ? (a) : (b)) #endif

#ifndef max #define max(a, b) (((a) > (b)) ? (a) : (b)) #endif

// // We want ASSERT defined as an expression, which was fixed after Windows 2000 //

#ifdef ASSERT #undef ASSERT #if DBG #define ASSERT(exp) /  ((!(exp)) ? /   (RtlAssert(#exp, __FILE__, __LINE__, NULL),FALSE) : /   TRUE) #else #define ASSERT(exp) ((void) 0) #endif #endif

#define ExFreePoolWithTag(a, b) ExFreePool((a))

#endif /* WINVER == 0x0500 */

#ifndef Add2Ptr #define Add2Ptr(P,I) ((PVOID)((PUCHAR)(P) + (I))) #endif

// // 在堆栈上的局部名字的缓冲尺寸 // Buffer size for local names on the stack //

#define MAX_DEVNAME_LENGTH    64

// Add content(增加内容)******

// 限制的最大路径长度 + 系统加密信息目录 #define MAX_PATH      512

// 加密位尺寸，设置加密位共128*8个位，即128字节 #define ENCRYPT_BIT_SIZE    (128 * 8)

#define SF_ENCRYPT_POSTFIX    L".$encrypt$" #define SF_ENCRYPT_POSTFIX_LENGTH  10

// 规则文件的文件名 #define RULE_FILE_NAME     L"//SystemRoot//xefs.dat"

#if DBG #define DEBUG_VOLUME     L'H' // L'G' #endif

/* typedef struct _FILE_OBJECT {     CSHORT Type;     CSHORT Size;     PDEVICE_OBJECT DeviceObject;     PVPB Vpb;     PVOID FsContext;     PVOID FsContext2;     PSECTION_OBJECT_POINTERS SectionObjectPointer;     PVOID PrivateCacheMap;     NTSTATUS FinalStatus;     struct _FILE_OBJECT *RelatedFileObject;     BOOLEAN LockOperation;     BOOLEAN DeletePending;     BOOLEAN ReadAccess;     BOOLEAN WriteAccess;     BOOLEAN DeleteAccess;     BOOLEAN SharedRead;     BOOLEAN SharedWrite;     BOOLEAN SharedDelete;     ULONG Flags;     UNICODE_STRING FileName;     LARGE_INTEGER CurrentByteOffset;     ULONG Waiters;     ULONG Busy;     PVOID LastLock;     KEVENT Lock;     KEVENT Event;     PIO_COMPLETION_CONTEXT CompletionContext; } FILE_OBJECT; typedef struct _FILE_OBJECT *PFILE_OBJECT; // ntndis */

typedef struct _FILE_CONTEXT_HDR {  PVOID FsContext; } FILE_CONTEXT_HDR, *PFILE_CONTEXT_HDR;

typedef struct _FILE_CONTEXT {  FILE_CONTEXT_HDR;

ULONG RefCount;  BOOLEAN DecryptOnRead;  // 是否读时解密  BOOLEAN EncryptOnWrite;  // 是否写时加密  BOOLEAN EncryptFlagExist; // 如果加密标志存在，那么文件被加密,if encrypt flag file exists, then the file is encrypted  BOOLEAN NeedEncrypt;  // 需要加密  BOOLEAN DeleteOnClose;  KEVENT Event;  WCHAR Name[MAX_PATH];  // 转换成字节数，// 表明从最终形成'/??/i:/System Encrypt Information/System Volume Information'的文件中读入的加密位的字节长度  UCHAR EncryptExtData[ENCRYPT_BIT_SIZE / sizeof(UCHAR)]; } FILE_CONTEXT, *PFILE_CONTEXT; // Add content(增加内容)******

// // Device extension definition for our driver.  Note that the same extension // is used for the following types of device objects: // - File system device object we attach to // - Mounted volume device objects we attach to // //  我们驱动的设备扩展。注意相同的扩展用于下面类型的设备对象 //      - 我们附着的文件系统设备对象 //      - 我们附着的被安装的卷设备对象

typedef struct _SFILTER_DEVICE_EXTENSION {  //  // Pointer to the file system device object we are attached to  //  PDEVICE_OBJECT AttachedToDeviceObject;

//  // Pointer to the real (disk) device object that is associated with  // the file system device object we are attached to  //  PDEVICE_OBJECT StorageStackDeviceObject;

//  // Name for this device.  If attached to a Volume Device Object it is the  // name of the physical disk drive.  If attached to a Control Device  // Object it is the name of the Control Device Object.  //  UNICODE_STRING DeviceName;

//  // Buffer used to hold the above unicode strings  //  WCHAR DeviceNameBuffer[MAX_DEVNAME_LENGTH];

WCHAR DriveLetter; // Add content(增加内容)

RTL_GENERIC_TABLE FsCtxTable; // Add content(增加内容)  FAST_MUTEX FsCtxTableMutex;  // Add content(增加内容) } SFILTER_DEVICE_EXTENSION, *PSFILTER_DEVICE_EXTENSION;

// // 这个结构含有我们需要为FSCTRLs传递到完成处理的信息 // This structure contains the information we need to pass to the completion // processing for FSCTRLs. // typedef struct _FSCTRL_COMPLETION_CONTEXT {  //  // The workitem that will be initialized with our context and  // worker routine if this completion processing needs to be completed  // in a worker thread.  // 如果这个完成处理需要在一个工作线程中完成，用我们的上下文和工作例程初始化的workitem  //  WORK_QUEUE_ITEM WorkItem;

//  // The device object to which this device is currently directed.  //  PDEVICE_OBJECT DeviceObject;

//  // The IRP for this FSCTRL operation.  // 这个FSCTRL操作的IRP  //  PIRP Irp;

//  // For mount operations, the new device object that we have allocated  // and partially initialized that we will attach to the mounted volume  // if the mount is successful.  // 对于卷安装操作，我们已经分配且部分初始化的我们将附着到被成功安装的卷的新设备对象  //  PDEVICE_OBJECT NewDeviceObject; } FSCTRL_COMPLETION_CONTEXT, *PFSCTRL_COMPLETION_CONTEXT;

typedef struct _POST_CREATE_WORKER_CONTEXT  // Add content(增加内容) {  WORK_QUEUE_ITEM WorkItem;  KEVENT Event;  PDEVICE_OBJECT DeviceObject;  PFILE_OBJECT FileObject;  PFILE_CONTEXT FileContext;  BOOLEAN NewElement; } POST_CREATE_WORKER_CONTEXT, *PPOST_CREATE_WORKER_CONTEXT;

typedef struct _READ_WRITE_COMPLETION_CONTEXT // Add content(增加内容) {  PMDL OldMdl;  PVOID OldUserBuffer;  PVOID OldSystemBuffer;

PMDL MdlForUserBuffer;    PVOID OldBuffer;  PVOID MyBuffer;  ULONG Length; } READ_WRITE_COMPLETION_CONTEXT, *PREAD_WRITE_COMPLETION_CONTEXT;

typedef struct _POST_SET_INFORMATION_WORKER_CONTEXT // Add content(增加内容) {  WORK_QUEUE_ITEM WorkItem;  KEVENT Event;  PDEVICE_OBJECT DeviceObject;  PFILE_OBJECT FileObject;  PFILE_CONTEXT FileContext;  PWCHAR FileName;  PWCHAR TargetFileName;  } POST_SET_INFORMATION_WORKER_CONTEXT, *PPOST_SET_INFORMATION_WORKER_CONTEXT;

#define POLICY_NONE   0x0   // Add content(增加内容) #define POLICY_ENCRYPT  0x1 #define POLICY_END   0xFFFFFFFF

typedef struct _RULE  // Add content(增加内容) {  ULONG Policy;    // 规则策略码  WCHAR Pattern[MAX_PATH]; // 匹配规则，可以含有通配符 * ? } RULE, *PRULE;

// // Macro to test if this is my device object // 用于测试是否我们设备对象的宏 // #define IS_MY_DEVICE_OBJECT(_devObj) /  (((_devObj) != NULL) && /   ((_devObj)->DriverObject == gSFilterDriverObject) && /    ((_devObj)->DeviceExtension != NULL))

// // Macro to test if this is my control device object // 用于测试是否我们的控制设备对象的宏 // #define IS_MY_CONTROL_DEVICE_OBJECT(_devObj) /  (((_devObj) == gSFilterControlDeviceObject) ? /    (ASSERT(((_devObj)->DriverObject == gSFilterDriverObject) && /      ((_devObj)->DeviceExtension == NULL)), TRUE) : /    FALSE)

// // Macro to test for device types we want to attach to // 测试我们想附着到的设备类型的宏 // #define IS_DESIRED_DEVICE_TYPE(_type) /  (((_type) == FILE_DEVICE_DISK_FILE_SYSTEM) || /   ((_type) == FILE_DEVICE_CD_ROM_FILE_SYSTEM) || /   ((_type) == FILE_DEVICE_NETWORK_FILE_SYSTEM))

// // Macro to test if FAST_IO_DISPATCH handling routine is valid // 测试是否FAST_IO_DISPATCH处理例程有效的宏 // #define VALID_FAST_IO_DISPATCH_HANDLER(_FastIoDispatchPtr, _FieldName) /  (((_FastIoDispatchPtr) != NULL) && /   (((_FastIoDispatchPtr)->SizeOfFastIoDispatch) >= /    (FIELD_OFFSET(FAST_IO_DISPATCH, _FieldName) + sizeof(void *))) && /   ((_FastIoDispatchPtr)->_FieldName != NULL))

#if WINVER >= 0x0501 // // MULTIVERSION NOTE: // // If built in the Windows XP environment or later, we will dynamically import // the function pointers for routines that were not supported on Windows 2000 // so that we can build a driver that will run, with modified logic, on // Windows 2000 or later. // // Below are the prototypes for the function pointers that we need to // dynamically import because not all OS versions support these routines. // // 动态输入函数的原型的函数指针

typedef NTSTATUS (* PSF_REGISTER_FILE_SYSTEM_FILTER_CALLBACKS)(  IN PDRIVER_OBJECT DriverObject,  IN PFS_FILTER_CALLBACKS Callbacks  );

typedef NTSTATUS (* PSF_ENUMERATE_DEVICE_OBJECT_LIST)(  IN PDRIVER_OBJECT DriverObject,  IN PDEVICE_OBJECT *DeviceObjectList,  IN ULONG DeviceObjectListSize,  OUT PULONG ActualNumberDeviceObjects  );

typedef NTSTATUS (* PSF_ATTACH_DEVICE_TO_DEVICE_STACK_SAFE)(  IN PDEVICE_OBJECT SourceDevice,  IN PDEVICE_OBJECT TargetDevice,  OUT PDEVICE_OBJECT *AttachedToDeviceObject  );

typedef PDEVICE_OBJECT (* PSF_GET_LOWER_DEVICE_OBJECT)(  IN PDEVICE_OBJECT DeviceObject  );

typedef PDEVICE_OBJECT (* PSF_GET_DEVICE_ATTACHMENT_BASE_REF)(  IN PDEVICE_OBJECT DeviceObject  );

typedef NTSTATUS (* PSF_GET_DISK_DEVICE_OBJECT)(  IN PDEVICE_OBJECT FileSystemDeviceObject,  OUT PDEVICE_OBJECT *DiskDeviceObject  );

typedef PDEVICE_OBJECT (* PSF_GET_ATTACHED_DEVICE_REFERENCE)(  IN PDEVICE_OBJECT DeviceObject  );

typedef NTSTATUS (* PSF_GET_VERSION)(  IN OUT PRTL_OSVERSIONINFOW VersionInformation  );

typedef struct _SF_DYNAMIC_FUNCTION_POINTERS {  //  // The following routines should all be available on Windows XP (5.1) and later.  // 下面这些例程应该在Windows XP (5.1)及以后的操作系统可用  //  PSF_REGISTER_FILE_SYSTEM_FILTER_CALLBACKS RegisterFileSystemFilterCallbacks;  PSF_ATTACH_DEVICE_TO_DEVICE_STACK_SAFE AttachDeviceToDeviceStackSafe;  PSF_ENUMERATE_DEVICE_OBJECT_LIST EnumerateDeviceObjectList;  PSF_GET_LOWER_DEVICE_OBJECT GetLowerDeviceObject;  PSF_GET_DEVICE_ATTACHMENT_BASE_REF GetDeviceAttachmentBaseRef;  PSF_GET_DISK_DEVICE_OBJECT GetDiskDeviceObject;  PSF_GET_ATTACHED_DEVICE_REFERENCE GetAttachedDeviceReference;  PSF_GET_VERSION GetVersion; } SF_DYNAMIC_FUNCTION_POINTERS, *PSF_DYNAMIC_FUNCTION_POINTERS;

SF_DYNAMIC_FUNCTION_POINTERS gSfDynamicFunctions = {NULL};

// // MULTIVERSION NOTE: For this version of the driver, we need to know the // current OS version while we are running to make decisions regarding what // logic to use when the logic cannot be the same for all platforms.  We // will look up the OS version in DriverEntry and store the values // in these global variables. // // 在DriverEntry中查找OS版本且存储值在这些全局变量中

ULONG gSfOsMajorVersion = 0; ULONG gSfOsMinorVersion = 0;

// // Here is what the major and minor versions should be for the various OS versions: // 这里是各种OS对应的主次版本号 // // OS Name         MajorVersion MinorVersion // --------------------------------------------------------------------- // Windows 2000        5     0 // Windows XP        5     1 // Windows Server 2003      5     2 //

#define IS_WINDOWS2000() /  ((gSfOsMajorVersion == 5) && (gSfOsMinorVersion == 0))

#define IS_WINDOWSXP() /  ((gSfOsMajorVersion == 5) && (gSfOsMinorVersion == 1))

#define IS_WINDOWSXP_OR_LATER() /  (((gSfOsMajorVersion == 5) && (gSfOsMinorVersion >= 1)) || /   (gSfOsMajorVersion > 5))

#define IS_WINDOWSSRV2003_OR_LATER() /  (((gSfOsMajorVersion == 5) && (gSfOsMinorVersion >= 2)) || /   (gSfOsMajorVersion > 5))

#endif

// // TAG identifying memory SFilter allocates // 标识SFilter分配内存的标记 //

#define SFLT_POOL_TAG   'tlFS'

// // This structure and these routines are used to retrieve the name of a file // object.  To prevent allocating memory every time we get a name this // structure contains a small buffer (which should handle 90+% of all names). // If we do overflow this buffer we will allocate a buffer big enough // for the name. //

typedef struct _GET_NAME_CONTROL {  PCHAR allocatedBuffer;  CHAR smallBuffer[256]; } GET_NAME_CONTROL, *PGET_NAME_CONTROL;

PUNICODE_STRING SfGetFileName(  IN PFILE_OBJECT FileObject,  IN NTSTATUS CreateStatus,  IN OUT PGET_NAME_CONTROL NameControl  );

VOID SfGetFileNameCleanup(  IN OUT PGET_NAME_CONTROL NameControl  );

// // Macros for SFilter DbgPrint levels. // 用于SFilter DbgPrint级的宏 // #define SF_LOG_PRINT(_dbgLevel, _string)      /  (FlagOn(SfDebug,(_dbgLevel)) ?        /   DbgPrint _string  :         /   ((void)0))

// // Delay values for KeDelayExecutionThread() // (Values are negative to represent relative time) // 用于KeDelayExecutionThread()的延迟值，（负值代表相对时间） // #define DELAY_ONE_MICROSECOND (-10) #define DELAY_ONE_MILLISECOND (DELAY_ONE_MICROSECOND*1000) #define DELAY_ONE_SECOND  (DELAY_ONE_MILLISECOND*1000)

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //     Global variables // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

// // Holds pointer to the driver object for this driver // 保持用于这个驱动的驱动对象的指针 // PDRIVER_OBJECT gSFilterDriverObject = NULL;

// // Holds pointer to the device object that represents this driver and is used // by external programs to access this driver.  This is also known as the // "control device object". // 保持代表这个驱动的且由外部程序使用存取这个驱动的设备对象的指针。 // 这也就是所谓的"control device object" // PDEVICE_OBJECT gSFilterControlDeviceObject = NULL;

// // This lock is used to synchronize our attaching to a given device object. // This lock fixes a race condition where we could accidently attach to the // same device object more then once.  This race condition only occurs if // a volume is being mounted at the same time as this filter is being loaded. // This problem will never occur if this filter is loaded at boot time before // any file systems are loaded. // // This lock is used to atomically test if we are already attached to a given // device object and if not, do the attach. // // 用于同步我们的附着到给定设备对象的锁 // 这个锁修正我们可能偶然附着到相同设备对象多次的竞争条件。这个竞争条件仅发生在 // 卷被安装的同时这个过滤器被载入。 // 这个问题当这个过滤器在任何文件系统被载入前就在启动时被载入的情况下不会发生 // 这个锁被用于自动测试是否我们已经附着到给定的设备对象且如果没有，执行附着。 FAST_MUTEX gSfilterAttachLock;

// Add content(增加内容)****** PAGED_LOOKASIDE_LIST gFileNameLookAsideList; PAGED_LOOKASIDE_LIST gFsCtxLookAsideList; NPAGED_LOOKASIDE_LIST gReadWriteCompletionCtxLookAsideList;

PRULE gRules = NULL; ERESOURCE gRulesResource; HANDLE gRuleFileHandle = NULL;

UCHAR gKey[128] = {0};

#define FSCTX_GENERIC_TABLE_POOL_SIZE  sizeof(FILE_CONTEXT) + 32 // Add content(增加内容)******

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //     Debug Definitions // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

// // DEBUG display flags //

/* #define SFDEBUG_DISPLAY_ATTACHMENT_NAMES    0x00000001  //display names of device objects we attach to #define SFDEBUG_DISPLAY_CREATE_NAMES        0x00000002  //get and display names during create #define SFDEBUG_GET_CREATE_NAMES            0x00000004  //get name (don't display) during create #define SFDEBUG_DO_CREATE_COMPLETION        0x00000008  //do create completion routine, don't get names #define SFDEBUG_ATTACH_TO_FSRECOGNIZER      0x00000010  //do attach to FSRecognizer device objects #define SFDEBUG_ATTACH_TO_SHADOW_COPIES     0x00000020  //do attach to ShadowCopy Volume device objects -- they are only around on Windows XP and later

ULONG SfDebug = 0; */

// 显示我们附着到的设备对象的名字 // Display names of device objects we attach to. // #define SFDEBUG_DISPLAY_ATTACHMENT_NAMES 0x00000001  // display names of device objects we attach to

// 得到文件名（在创建期间）且显示他们（创建完成） // Get file names (during create) and display them (create completion). // #define SFDEBUG_DISPLAY_CREATE_NAMES  0x00000002  // get and display names during create

// 得到文件名但不显示他们（在创建期间） // Get file names but don't display them (during create). // #define SFDEBUG_GET_CREATE_NAMES   0x00000004  // get name (don't display) during create

// 执行创建完成例程，忽略名字显示 // Do create completion routine, regardless of name display. // #define SFDEBUG_DO_CREATE_COMPLETION  0x00000008  // do create completion routine, don't get names

// 执行附着到FSRecognizer设备对象 // Do attach to FSRecognizer device objects. // #define SFDEBUG_ATTACH_TO_FSRECOGNIZER  0x00000010  // do attach to FSRecognizer device objects

// 执行附着到ShadowCopy卷设备对象--他们仅在Windows XP及以后OS发生 // Do attach to ShadowCopy Volume device objects -- they are only around on // Windows XP and later. // #define SFDEBUG_ATTACH_TO_SHADOW_COPIES  0x00000020  // do attach to ShadowCopy Volume device objects -- they are only around on Windows XP and later

// 执行得到和使用DOS设备名字用于文件名的显示 // Do get and use DOS device names for file name display. // //#define SFDEBUG_GET_DOS_NAMES               0x00000040

// 在清除/关闭时间显示信息 // Display information at cleanup/close time // //#define SFDEBUG_DISPLAY_CLEANUPCLOSE_NAMES  0x00000080

// 保持调试状态的全局变量 // Global which holds debug state // ULONG SfDebug = 0;

// // Given a device type, return a valid name // 给出一个设备类型，返回一个有效名字 //

#define GET_DEVICE_TYPE_NAME(_type) /    ((((_type) > 0) && ((_type) < (sizeof(DeviceTypeNames) / sizeof(PCHAR)))) ? /     DeviceTypeNames[ (_type) ] : /     "[Unknown]")

// // Known device type names // 已知设备类名称 //

static const PCHAR DeviceTypeNames[] = {  "",  "BEEP",  "CD_ROM",  "CD_ROM_FILE_SYSTEM",  "CONTROLLER",  "DATALINK",  "DFS",  "DISK",  "DISK_FILE_SYSTEM",  "FILE_SYSTEM",  "INPORT_PORT",  "KEYBOARD",  "MAILSLOT",  "MIDI_IN",  "MIDI_OUT",  "MOUSE",  "MULTI_UNC_PROVIDER",  "NAMED_PIPE",  "NETWORK",  "NETWORK_BROWSER",  "NETWORK_FILE_SYSTEM",  "NULL",  "PARALLEL_PORT",  "PHYSICAL_NETCARD",  "PRINTER",  "SCANNER",  "SERIAL_MOUSE_PORT",  "SERIAL_PORT",  "SCREEN",  "SOUND",  "STREAMS",  "TAPE",  "TAPE_FILE_SYSTEM",  "TRANSPORT",  "UNKNOWN",  "VIDEO",  "VIRTUAL_DISK",  "WAVE_IN",  "WAVE_OUT",  "8042_PORT",  "NETWORK_REDIRECTOR",  "BATTERY",  "BUS_EXTENDER",  "MODEM",  "VDM",  "MASS_STORAGE",  "SMB",  "KS",  "CHANGER",  "SMARTCARD",  "ACPI",  "DVD",  "FULLSCREEN_VIDEO",  "DFS_FILE_SYSTEM",  "DFS_VOLUME",  "SERENUM",  "TERMSRV",  "KSEC" };

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //      Function Prototypes // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

int __cdecl swprintf(wchar_t *, const wchar_t *, ...); // Add content(增加内容)

// // Define driver entry routine. //

NTSTATUS DriverEntry(  IN PDRIVER_OBJECT DriverObject,  IN PUNICODE_STRING RegistryPath  );

#if DBG && WINVER >= 0x0501 VOID DriverUnload(  IN PDRIVER_OBJECT DriverObject  ); #endif

// // Define the local routines used by this driver module.  This includes a // a sample of how to filter a create file operation, and then invoke an I/O // completion routine when the file has successfully been created/opened. // //  定义由这个驱动模块使用的局部例程。这包括一个如何过滤一个创建文件操作的例子， //  且然后当文件已经成功被创建/打开时调用一个I/O完成例程

#if WINVER >= 0x0501 VOID SfLoadDynamicFunctions(  );

VOID SfGetCurrentVersion(  ); #endif

NTSTATUS SfPassThrough(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS SfCreate(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

// 缺少sfCreateCompletion(...)

NTSTATUS SfCleanup(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

// 将 SfCleanupClose(...)分成SfCleanup(...)和SfClose(...).

NTSTATUS SfClose(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS // Add content(增加内容) SfRead(    IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS // Add content(增加内容) SfReadCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  );

NTSTATUS // Add content(增加内容) SfWrite(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS // Add content(增加内容) SfWriteCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  );

NTSTATUS // Add content(增加内容) SfDirectoryControl (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS // Add content(增加内容) SfSetInformation (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS SfFsControl(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS SfFsControlMountVolume (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

VOID SfFsControlMountVolumeCompleteWorker (  IN PFSCTRL_COMPLETION_CONTEXT Context  );

NTSTATUS SfFsControlMountVolumeComplete (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PDEVICE_OBJECT NewDeviceObject  );

NTSTATUS SfFsControlLoadFileSystem (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

VOID SfFsControlLoadFileSystemCompleteWorker (  IN PFSCTRL_COMPLETION_CONTEXT Context  );

NTSTATUS SfFsControlLoadFileSystemComplete (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS SfFsControlCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  );

BOOLEAN SfFastIoCheckIfPossible(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  IN BOOLEAN CheckForReadOperation,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoRead(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  OUT PVOID Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoWrite(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  IN PVOID Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoQueryBasicInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_BASIC_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoQueryStandardInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_STANDARD_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoLock(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PLARGE_INTEGER Length,  PEPROCESS ProcessId,  ULONG Key,  BOOLEAN FailImmediately,  BOOLEAN ExclusiveLock,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoUnlockSingle(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PLARGE_INTEGER Length,  PEPROCESS ProcessId,  ULONG Key,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoUnlockAll(  IN PFILE_OBJECT FileObject,  PEPROCESS ProcessId,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoUnlockAllByKey(  IN PFILE_OBJECT FileObject,  PVOID ProcessId,  ULONG Key,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoDeviceControl(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  IN PVOID InputBuffer OPTIONAL,  IN ULONG InputBufferLength,  OUT PVOID OutputBuffer OPTIONAL,  IN ULONG OutputBufferLength,  IN ULONG IoControlCode,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

VOID SfFastIoDetachDevice(  IN PDEVICE_OBJECT SourceDevice,  IN PDEVICE_OBJECT TargetDevice  );

BOOLEAN SfFastIoQueryNetworkOpenInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_NETWORK_OPEN_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoMdlRead(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoMdlReadComplete(  IN PFILE_OBJECT FileObject,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoPrepareMdlWrite(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoMdlWriteComplete(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoReadCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PVOID Buffer,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  OUT struct _COMPRESSED_DATA_INFO *CompressedDataInfo,  IN ULONG CompressedDataInfoLength,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoWriteCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  IN PVOID Buffer,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN struct _COMPRESSED_DATA_INFO *CompressedDataInfo,  IN ULONG CompressedDataInfoLength,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoMdlReadCompleteCompressed(  IN PFILE_OBJECT FileObject,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoMdlWriteCompleteCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  );

BOOLEAN SfFastIoQueryOpen(  IN PIRP Irp,  OUT PFILE_NETWORK_OPEN_INFORMATION NetworkInformation,  IN PDEVICE_OBJECT DeviceObject  );

#if WINVER >= 0x0501 /* See comment in DriverEntry */ NTSTATUS SfPreFsFilterPassThrough(  IN PFS_FILTER_CALLBACK_DATA Data,  OUT PVOID *CompletionContext  );

VOID SfPostFsFilterPassThrough(  IN PFS_FILTER_CALLBACK_DATA Data,  IN NTSTATUS OperationStatus,  IN PVOID CompletionContext  ); #endif

VOID SfFsNotification(  IN PDEVICE_OBJECT DeviceObject,  IN BOOLEAN FsActive  );

NTSTATUS SfAttachDeviceToDeviceStack(  IN PDEVICE_OBJECT SourceDevice,  IN PDEVICE_OBJECT TargetDevice,  IN OUT PDEVICE_OBJECT *AttachedToDeviceObject  );

NTSTATUS SfAttachToFileSystemDevice(  IN PDEVICE_OBJECT DeviceObject,  IN PUNICODE_STRING DeviceName  );

VOID SfDetachFromFileSystemDevice(  IN PDEVICE_OBJECT DeviceObject  );

NTSTATUS SfAttachToMountedDevice(  IN PDEVICE_OBJECT DeviceObject,  IN PDEVICE_OBJECT SFilterDeviceObject  );

VOID SfCleanupMountedDevice(  IN PDEVICE_OBJECT DeviceObject  );

#if WINVER >= 0x0501 NTSTATUS SfEnumerateFileSystemVolumes(  IN PDEVICE_OBJECT FSDeviceObject,  IN PUNICODE_STRING FSName  ); #endif

VOID SfGetObjectName(  IN PVOID Object,  IN OUT PUNICODE_STRING Name  );

VOID SfGetBaseDeviceObjectName(  IN PDEVICE_OBJECT DeviceObject,  IN OUT PUNICODE_STRING DeviceName  );

BOOLEAN SfIsAttachedToDevice(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  );

BOOLEAN SfIsAttachedToDeviceW2K(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  );

BOOLEAN SfIsAttachedToDeviceWXPAndLater(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  );

VOID SfReadDriverParameters(  IN PUNICODE_STRING RegistryPath  );

VOID  // Add content(增加内容) SfDriverReinitialization(     IN PDRIVER_OBJECT DriverObject,     IN PVOID Context,     IN ULONG Count     );

NTSTATUS SfIsShadowCopyVolume (  IN PDEVICE_OBJECT StorageStackDeviceObject,  OUT PBOOLEAN IsShadowCopy  );

BOOLEAN  // Add content(增加内容) SfDissectFileName(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  OUT PWSTR FileName  );

RTL_GENERIC_COMPARE_RESULTS  // Add content(增加内容) SfGenericCompareRoutine(  IN PRTL_GENERIC_TABLE Table,  IN PVOID FirstStruct,  IN PVOID SecondStruct  );

PVOID  // Add content(增加内容) SfGenericAllocateRoutine(  IN PRTL_GENERIC_TABLE Table,  IN CLONG ByteSize  );

VOID  // Add content(增加内容) SfGenericFreeRoutine(  IN PRTL_GENERIC_TABLE Table,  IN PVOID Buffer  );

NTSTATUS // Add content(增加内容) SfIsEncryptFlagExist(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  OUT PBOOLEAN Encrypted,  OUT PVOID Data,  IN ULONG DataLength  );

NTSTATUS // Add content(增加内容) SfIsFileNeedEncrypt(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  OUT PBOOLEAN NeedEncrypt  );

NTSTATUS // Add content(增加内容) SfSetFileEncrypted(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  IN BOOLEAN IsEncrypted,  IN PVOID Data,  IN ULONG DataLength  );

NTSTATUS // Add content(增加内容) SfUpdateFileByFileObject(  IN PDEVICE_OBJECT DeviceObject,  IN PFILE_OBJECT FileObject  );

NTSTATUS // Add content(增加内容) SfIssueReadWriteIrpSynchronously(  IN PDEVICE_OBJECT DeviceObject,  IN PFILE_OBJECT FileObject,  IN ULONG MajorFunction,  IN PIO_STATUS_BLOCK IoStatus,  IN PVOID Buffer,  IN ULONG Length,  IN PLARGE_INTEGER ByteOffset,  IN ULONG IrpFlags  );

NTSTATUS // Add content(增加内容) SfIssueCleanupIrpSynchronously(  IN PDEVICE_OBJECT NextDeviceObject,  IN PIRP Irp,  IN PFILE_OBJECT FileObject  );

NTSTATUS // Add content(增加内容) SfCreateFile(  IN PCWSTR FileName,  IN ULONG FileAttributes,  IN BOOLEAN IsFile  );

NTSTATUS // Add content(增加内容) SfRenameFile(  IN PWSTR SrcFileName,  IN PWSTR DstFileName  );

NTSTATUS // Add content(增加内容) SfForwardIrpSyncronously(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  );

NTSTATUS // Add content(增加内容) SfLoadRules(  OUT PHANDLE FileHandle  );

ULONG  // Add content(增加内容) SfMatchRules(  IN PCWSTR FileName  );

BOOLEAN  // Add content(增加内容) SfMatchWithPattern(  IN PCWSTR Pattern,  IN PCWSTR Name  );

BOOLEAN  // Add content(增加内容) SfMatchOkay(  IN PCWSTR Pattern  );

BOOLEAN  // Add content(增加内容) SfIsObjectFile(  IN PFILE_OBJECT FileObject  );

NTSTATUS // Add content(增加内容) SfQuerySymbolicLink(     IN  PUNICODE_STRING SymbolicLinkName,     OUT PUNICODE_STRING LinkTarget     );

NTSTATUS // Add content(增加内容) SfVolumeDeviceNameToDosName(     IN PUNICODE_STRING VolumeDeviceName,     OUT PUNICODE_STRING DosName     );     // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // // Assign text sections for each routine. // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

#ifdef ALLOC_PRAGMA #pragma alloc_text(INIT, DriverEntry)

#if DBG && WINVER >= 0x0501 #pragma alloc_text(PAGE, DriverUnload) #endif

#pragma alloc_text(PAGE, SfFsNotification) #pragma alloc_text(PAGE, SfCreate) #pragma alloc_text(PAGE, SfCleanup)  // Add content(增加内容) #pragma alloc_text(PAGE, SfClose) #pragma alloc_text(PAGE, SfFsControl) #pragma alloc_text(PAGE, SfFsControlMountVolume) #pragma alloc_text(PAGE, SfFsControlMountVolumeComplete) #pragma alloc_text(PAGE, SfFsControlLoadFileSystem) #pragma alloc_text(PAGE, SfFsControlLoadFileSystemComplete) #pragma alloc_text(PAGE, SfFastIoCheckIfPossible) #pragma alloc_text(PAGE, SfFastIoRead) #pragma alloc_text(PAGE, SfFastIoWrite) #pragma alloc_text(PAGE, SfFastIoQueryBasicInfo) #pragma alloc_text(PAGE, SfFastIoQueryStandardInfo) #pragma alloc_text(PAGE, SfFastIoLock) #pragma alloc_text(PAGE, SfFastIoUnlockSingle) #pragma alloc_text(PAGE, SfFastIoUnlockAll) #pragma alloc_text(PAGE, SfFastIoUnlockAllByKey) #pragma alloc_text(PAGE, SfFastIoDeviceControl) #pragma alloc_text(PAGE, SfFastIoDetachDevice) #pragma alloc_text(PAGE, SfFastIoQueryNetworkOpenInfo) #pragma alloc_text(PAGE, SfFastIoMdlRead) #pragma alloc_text(PAGE, SfFastIoPrepareMdlWrite) #pragma alloc_text(PAGE, SfFastIoMdlWriteComplete) #pragma alloc_text(PAGE, SfFastIoReadCompressed) #pragma alloc_text(PAGE, SfFastIoWriteCompressed) #pragma alloc_text(PAGE, SfFastIoQueryOpen) #pragma alloc_text(PAGE, SfAttachDeviceToDeviceStack) #pragma alloc_text(PAGE, SfAttachToFileSystemDevice) #pragma alloc_text(PAGE, SfDetachFromFileSystemDevice) #pragma alloc_text(PAGE, SfAttachToMountedDevice) #pragma alloc_text(PAGE, SfIsAttachedToDevice) #pragma alloc_text(PAGE, SfIsAttachedToDeviceW2K) //#pragma alloc_text(PAGE, SfReadDriverParameters) // 缺少 #pragma alloc_text(PAGE, SfDriverReinitialization) // Add content(增加内容) #pragma alloc_text(PAGE, SfIsShadowCopyVolume)

#if WINVER >= 0x0501 #pragma alloc_text(INIT, SfLoadDynamicFunctions) #pragma alloc_text(INIT, SfGetCurrentVersion) #pragma alloc_text(PAGE, SfEnumerateFileSystemVolumes) #pragma alloc_text(PAGE, SfIsAttachedToDeviceWXPAndLater) #endif

#pragma alloc_text(PAGE, SfQuerySymbolicLink) // Add content(增加内容) #pragma alloc_text(PAGE, SfVolumeDeviceNameToDosName) // Add content(增加内容) #endif

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //     Functions // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

NTSTATUS DriverEntry(  IN PDRIVER_OBJECT DriverObject,  IN PUNICODE_STRING RegistryPath  ) /*++

Routine Description:

// 创建设备对象且登记它监视所有的活动文件系统  This is the initialization routine for the SFILTER file system filter  driver.  This routine creates the device object that represents this  driver in the system and registers it for watching all file systems that  register or unregister themselves as active file systems.

Arguments:

DriverObject - Pointer to driver object created by the system.

Return Value:

The function value is the final status from the initialization operation.

--*/ {  PFAST_IO_DISPATCH FastIoDispatch;  UNICODE_STRING NameString;  NTSTATUS Status;  ULONG i;

UNREFERENCED_PARAMETER(RegistryPath);

#if WINVER >= 0x0501  //  // Try to load the dynamic functions that may be available for our use.  // 试图载入动态函数  //  SfLoadDynamicFunctions();

//  // Now get the current OS version that we will use to determine what logic  // paths to take when this driver is built to run on various OS version.  // 得到OS版本  //  SfGetCurrentVersion(); #endif

//  // Save our Driver Object, set our UNLOAD routine  // 保存我们的驱动对象，设置我们的UNLOAD例程  //

gSFilterDriverObject = DriverObject;

#if DBG && WINVER >= 0x0501

//  // MULTIVERSION NOTE:  //  // We can only support unload for testing environments if we can enumerate  // the outstanding device objects that our driver has.  // 如果我们可以枚举我们驱动拥有的显著的设备对象，仅支持测试环境的卸载  //    //  // Unload is useful for development purposes. It is not recommended for  // production versions  // 卸载只用于开发环境  //  if (NULL != gSfDynamicFunctions.EnumerateDeviceObjectList)    gSFilterDriverObject->DriverUnload = DriverUnload; #endif

// 初始化一个资源变量，可被用于同步一线程集合，  // 在释放资源占用内存前调用ExDeleteResourceLite  //  Status = ExInitializeResourceLite(&gRulesResource);  if (!NT_SUCCESS(Status))  {   KdPrint(("SFilter!DriverEntry: ExInitializeResourceLite failed, Status=%08x/n", Status));   return Status;  }

//  // Setup other global variables  // 设置其它全局变量  //  ExInitializeFastMutex(&gSfilterAttachLock);

ExInitializePagedLookasideList(   &gFsCtxLookAsideList,   NULL,   NULL,   0,   FSCTX_GENERIC_TABLE_POOL_SIZE,   SFLT_POOL_TAG,   0   );    ExInitializePagedLookasideList(   &gFileNameLookAsideList,   NULL,   NULL,   0,   MAX_PATH * sizeof(WCHAR),   SFLT_POOL_TAG,   0   );

ExInitializeNPagedLookasideList(   &gReadWriteCompletionCtxLookAsideList,   NULL,   NULL,   0,   sizeof(READ_WRITE_COMPLETION_CONTEXT),   SFLT_POOL_TAG,   0   );

//  // Create the Control Device Object (CDO).  This object represents this  // driver.  Note that it does not have a device extension.  // 创建控制设备对象，这个对象代表这个驱动。注意它没有设备扩展。  //  RtlInitUnicodeString(&NameString, L"//FileSystem//Filters//SFilterCDO");

Status = IoCreateDevice(   DriverObject,   0,       // has no device extension   &NameString,   FILE_DEVICE_DISK_FILE_SYSTEM,   FILE_DEVICE_SECURE_OPEN,   FALSE,   &gSFilterControlDeviceObject   );  if (Status == STATUS_OBJECT_PATH_NOT_FOUND)  {   //   // This must be a version of the OS that doesn't have the Filters   // path in its namespace.  This was added in Windows XP.   //   // We will try just putting our control device object in the /FileSystem   // portion of the object name space.   // XP以前的版本名字空间中未加入Filters路径，所以将我们的控制设备对象放入         // 对象名字空间的/FileSystem部分   //

RtlInitUnicodeString(&NameString, L"//FileSystem//SFilterCDO");

Status = IoCreateDevice(    DriverObject,    0,       // has no device extension    &NameString,    FILE_DEVICE_DISK_FILE_SYSTEM,    FILE_DEVICE_SECURE_OPEN,    FALSE,    &gSFilterControlDeviceObject    );   if (!NT_SUCCESS(Status))   {    KdPrint(("SFilter!DriverEntry: Error creating control device object /"%wZ/", Status=%08x/n", &NameString, Status));    ExDeleteResourceLite(&gRulesResource);    return Status;   }  }  else if (!NT_SUCCESS(Status))  {   KdPrint(("SFilter!DriverEntry: Error creating control device object /"%wZ/", Status=%08x/n", &NameString, Status));   ExDeleteResourceLite(&gRulesResource);   return Status;  }

//  // Initialize the driver object with this device driver's entry points.  //  for (i = 0; i <= IRP_MJ_MAXIMUM_FUNCTION; i++)  {   DriverObject->MajorFunction[i] = SfPassThrough;  }

//  // We will use SfCreate for all the create operations  //  DriverObject->MajorFunction[IRP_MJ_CREATE] = SfCreate;  DriverObject->MajorFunction[IRP_MJ_CREATE_NAMED_PIPE] = SfCreate;  DriverObject->MajorFunction[IRP_MJ_CREATE_MAILSLOT] = SfCreate;    DriverObject->MajorFunction[IRP_MJ_FILE_SYSTEM_CONTROL] = SfFsControl;  DriverObject->MajorFunction[IRP_MJ_CLEANUP] = SfCleanup;  DriverObject->MajorFunction[IRP_MJ_CLOSE] = SfClose;  DriverObject->MajorFunction[IRP_MJ_READ] = SfRead;  DriverObject->MajorFunction[IRP_MJ_WRITE] = SfWrite;  DriverObject->MajorFunction[IRP_MJ_DIRECTORY_CONTROL] = SfDirectoryControl;  DriverObject->MajorFunction[IRP_MJ_SET_INFORMATION] = SfSetInformation;

//  // Allocate fast I/O data structure and fill it in.  // 分配快速I/O数据结构且填入它  //  // NOTE:  The following FastIo Routines are not supported:  // AcquireFileForNtCreateSection  // ReleaseFileForNtCreateSection  // AcquireForModWrite  // ReleaseForModWrite  // AcquireForCcFlush  // ReleaseForCcFlush  //  // For historical reasons these FastIO's have never been sent to filters  // by the NT I/O system.  Instead, they are sent directly to the base  // file system.  On Windows XP and later OS releases, you can use the new  // system routine "FsRtlRegisterFileSystemFilterCallbacks" if you need to  // intercept these callbacks (see below).  // 由于历史的原因，这些快速IO不发送到过滤驱动，而是直接发送到基础文件系统。     // 在WINXP及以后版本，如果你想拦截这些回调，你可以使用新的系  // 统例程FsRtlRegisterFileSystemFilterCallbacks  //

FastIoDispatch = ExAllocatePoolWithTag(NonPagedPool, sizeof(FAST_IO_DISPATCH), SFLT_POOL_TAG);  if (!FastIoDispatch)  {   IoDeleteDevice(gSFilterControlDeviceObject);   ExDeleteResourceLite(&gRulesResource);   return STATUS_INSUFFICIENT_RESOURCES;  }

RtlZeroMemory(FastIoDispatch, sizeof(FAST_IO_DISPATCH));

FastIoDispatch->SizeOfFastIoDispatch = sizeof(FAST_IO_DISPATCH);  FastIoDispatch->FastIoCheckIfPossible = SfFastIoCheckIfPossible;  FastIoDispatch->FastIoRead = SfFastIoRead;  FastIoDispatch->FastIoWrite = SfFastIoWrite;  FastIoDispatch->FastIoQueryBasicInfo = SfFastIoQueryBasicInfo;  FastIoDispatch->FastIoQueryStandardInfo = SfFastIoQueryStandardInfo;  FastIoDispatch->FastIoLock = SfFastIoLock;  FastIoDispatch->FastIoUnlockSingle = SfFastIoUnlockSingle;  FastIoDispatch->FastIoUnlockAll = SfFastIoUnlockAll;  FastIoDispatch->FastIoUnlockAllByKey = SfFastIoUnlockAllByKey;  FastIoDispatch->FastIoDeviceControl = SfFastIoDeviceControl;  FastIoDispatch->FastIoDetachDevice = SfFastIoDetachDevice;  FastIoDispatch->FastIoQueryNetworkOpenInfo = SfFastIoQueryNetworkOpenInfo;  FastIoDispatch->MdlRead = SfFastIoMdlRead;  FastIoDispatch->MdlReadComplete = SfFastIoMdlReadComplete;  FastIoDispatch->PrepareMdlWrite = SfFastIoPrepareMdlWrite;  FastIoDispatch->MdlWriteComplete = SfFastIoMdlWriteComplete;  FastIoDispatch->FastIoReadCompressed = SfFastIoReadCompressed;  FastIoDispatch->FastIoWriteCompressed = SfFastIoWriteCompressed;  FastIoDispatch->MdlReadCompleteCompressed = SfFastIoMdlReadCompleteCompressed;  FastIoDispatch->MdlWriteCompleteCompressed = SfFastIoMdlWriteCompleteCompressed;  FastIoDispatch->FastIoQueryOpen = SfFastIoQueryOpen;

DriverObject->FastIoDispatch = FastIoDispatch;

// // VERSION NOTE: // // There are 6 FastIO routines for which file system filters are bypassed as // the requests are passed directly to the base file system.  These 6 routines // are AcquireFileForNtCreateSection, ReleaseFileForNtCreateSection, // AcquireForModWrite, ReleaseForModWrite, AcquireForCcFlush, and // ReleaseForCcFlush. // // In Windows XP and later, the FsFilter callbacks were introduced to allow // filters to safely hook these operations.  See the IFS Kit documentation for // more details on how these new interfaces work. // // MULTIVERSION NOTE: // // If built for Windows XP or later, this driver is built to run on // multiple versions.  When this is the case, we will test // for the presence of FsFilter callbacks registration API.  If we have it, // then we will register for those callbacks, otherwise, we will not. //

#if WINVER >= 0x0501

{   FS_FILTER_CALLBACKS FsFilterCallbacks;

if (NULL != gSfDynamicFunctions.RegisterFileSystemFilterCallbacks)   {    //    // Setup the callbacks for the operations we receive through    // the FsFilter interface.    // 为我们通过FsFilter接口接收的操作设置回调    //    // NOTE:  You only need to register for those routines you really need    //  to handle.  SFilter is registering for all routines simply to    //  give an example of how it is done.    //    FsFilterCallbacks.SizeOfFsFilterCallbacks = sizeof(FS_FILTER_CALLBACKS);    FsFilterCallbacks.PreAcquireForSectionSynchronization = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostAcquireForSectionSynchronization = SfPostFsFilterPassThrough;    FsFilterCallbacks.PreReleaseForSectionSynchronization = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostReleaseForSectionSynchronization = SfPostFsFilterPassThrough;    FsFilterCallbacks.PreAcquireForCcFlush = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostAcquireForCcFlush = SfPostFsFilterPassThrough;    FsFilterCallbacks.PreReleaseForCcFlush = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostReleaseForCcFlush = SfPostFsFilterPassThrough;    FsFilterCallbacks.PreAcquireForModifiedPageWriter = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostAcquireForModifiedPageWriter = SfPostFsFilterPassThrough;    FsFilterCallbacks.PreReleaseForModifiedPageWriter = SfPreFsFilterPassThrough;    FsFilterCallbacks.PostReleaseForModifiedPageWriter = SfPostFsFilterPassThrough;

Status = (gSfDynamicFunctions.RegisterFileSystemFilterCallbacks)(DriverObject, &FsFilterCallbacks);    if (!NT_SUCCESS(Status))    {     DriverObject->FastIoDispatch = NULL;     ExFreePool(FastIoDispatch);     IoDeleteDevice(gSFilterControlDeviceObject);     ExDeleteResourceLite(&gRulesResource);     return Status;    }   }  } #endif

//  // The registered callback routine "SfFsNotification" will be called  // whenever a new file systems is loaded or when any file system is  // unloaded.  // 当一个新的文件系统被装入或者当任何文件系统被卸载时，注册的回调函数     // SfFsNotification将被调用  //  // VERSION NOTE:  //  // On Windows XP and later this will also enumerate all existing file  // systems (except the RAW file systems).  On Windows 2000 this does not  // enumerate the file systems that were loaded before this filter was  // loaded.  //  Status = IoRegisterFsRegistrationChange(DriverObject, SfFsNotification);  if (!NT_SUCCESS(Status))  {   KdPrint(("SFilter!DriverEntry: Error registering FS change notification, Status=%08x/n", Status));

DriverObject->FastIoDispatch = NULL;   ExFreePool(FastIoDispatch);   IoDeleteDevice(gSFilterControlDeviceObject);   ExDeleteResourceLite(&gRulesResource);   return Status;  }

//  // Attempt to attach to the appropriate RAW file system device objects  // since they are not enumerated by IoRegisterFsRegistrationChange.  // 试图附着到合适的RAW文件系统设备对象，因为他们没有被IoRegisterFsRegistrationChange枚举  //  {   PDEVICE_OBJECT RawDeviceObject;   PFILE_OBJECT FileObject;

//   // Attach to RawDisk device   // 附着到RawDisk设备   //   RtlInitUnicodeString(&NameString, L"//Device//RawDisk");   Status = IoGetDeviceObjectPointer(    &NameString,    FILE_READ_ATTRIBUTES,    &FileObject,    &RawDeviceObject    );   if (NT_SUCCESS(Status))   {    SfFsNotification(RawDeviceObject, TRUE);    ObDereferenceObject(FileObject);   }

//   // Attach to the RawCdRom device   // 附着到RawCdRom设备   //   RtlInitUnicodeString(&NameString, L"//Device//RawCdRom");   Status = IoGetDeviceObjectPointer(    &NameString,    FILE_READ_ATTRIBUTES,    &FileObject,    &RawDeviceObject    );   if (NT_SUCCESS(Status))   {    SfFsNotification(RawDeviceObject, TRUE);    ObDereferenceObject(FileObject);   }  }

//  // Clear the initializing flag on the control device object since we  // have now successfully initialized everything.  // 清除控制设备对象上的初始化标志，因为我们现在成功完成初始化  //  ClearFlag(gSFilterControlDeviceObject->Flags, DO_DEVICE_INITIALIZING);

IoRegisterDriverReinitialization(DriverObject, SfDriverReinitialization, NULL);

return STATUS_SUCCESS; }

#if DBG && WINVER >= 0x0501 VOID DriverUnload(  IN PDRIVER_OBJECT DriverObject  ) /*++

Routine Description:

This routine is called when a driver can be unloaded.  This performs all of  the necessary cleanup for unloading the driver from memory.  Note that an  error can NOT be returned from this routine.  // 执行所有从内存中卸载驱动必要的清除操作，注意错误不能从这个例程返回    When a request is made to unload a driver the IO System will cache that  information and not actually call this routine until the following states  have occurred:  - All device objects which belong to this filter are at the top of their    respective attachment chains.  - All handle counts for all device objects which belong to this filter have    gone to zero.  // 当发出卸载一个驱动请求，IO系统将缓冲那个信息且不真正调用这个例程直到下面状态发生：   - 所有属于这个过滤的设备对象在他们各自附着链的顶部   - 所有设备对象的句柄计数已经成为0

WARNING: Microsoft does not officially support the unloading of File     System Filter Drivers.  This is an example of how to unload     your driver if you would like to use it during development.     This should not be made available in production code.

Arguments:

DriverObject - Driver object for this module

Return Value:

None.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt;  PFAST_IO_DISPATCH FastIoDispatch;  NTSTATUS Status;  ULONG NumDevices;  ULONG i;  LARGE_INTEGER Interval; # define DEVOBJ_LIST_SIZE 64  PDEVICE_OBJECT DevList[DEVOBJ_LIST_SIZE];

ASSERT(DriverObject == gSFilterDriverObject);

//  // Log we are unloading  // 我们卸载时做日志  //  SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,       ("SFilter!DriverUnload:      Unloading driver (%p)/n",      DriverObject));

//  // Don't get anymore file system change notifications  // 不得到任何文件系统改变通知  //  IoUnregisterFsRegistrationChange(DriverObject, SfFsNotification);

//  // This is the loop that will go through all of the devices we are attached  // to and detach from them.  Since we don't know how many there are and  // we don't want to allocate memory (because we can't return an error)  // we will free them in chunks using a local array on the stack.  // 这是遍历我们附着到的所有设备且断开他们的循环。因为我们不知道有多少且  // 我们不想分配内存（因为我们不能返回错误）。  // 我们将使用堆栈上的本地数组按块释放他们  //  for (;;)  {   //   // Get what device objects we can for this driver.  Quit if there   // are not any more.  Note that this routine should always be   // defined since this routine is only compiled for Windows XP and   // later.   // 为这个驱动得到设备对象。如果没有了，就退出。注意这个例程应该被定义   // 因为这个例程仅为Windows XP及以后的OS编译。   //

ASSERT(NULL != gSfDynamicFunctions.EnumerateDeviceObjectList);   Status = (gSfDynamicFunctions.EnumerateDeviceObjectList)(    DriverObject,    DevList,    sizeof(DevList),    &NumDevices    );

if (NumDevices <= 0)    break;

NumDevices = min(NumDevices, DEVOBJ_LIST_SIZE);

//   // First go through the list and detach each of the devices.   // Our control device object does not have a DeviceExtension and   // is not attached to anything so don't detach it.   // 首先遍历列表且断开每个设备。我们的控制设备对象没有DeviceExtension   // 且未附着到任何事情，因此不断开它。   //   for (i=0; i < NumDevices; i++)   {    DevExt = DevList[i]->DeviceExtension;    if (NULL != DevExt)     IoDetachDevice(DevExt->AttachedToDeviceObject);   }

//   // The IO Manager does not currently add a reference count to a device   // object for each outstanding IRP.  This means there is no way to   // know if there are any outstanding IRPs on the given device.   // We are going to wait for a reasonable amount of time for pending   // irps to complete.   // IO Manager当前不为每个未处理的IRPs增加设备对象的引用计数。这意味着无法知道   // 给定设备是否存在未处理的IRPs.我们将等待合理的时间完成这些IRPs。   // 象opLocks和目录改变通知的重负荷系统，可能发生问题   //   // WARNING: This does not work 100% of the time and the driver may be   //   unloaded before all IRPs are completed.  This can easily   //   occur under stress situations and if a long lived IRP is   //   pending (like oplocks and directory change notifications).   //   The system will fault when this Irp actually completes.   //   This is a sample of how to do this during testing.  This   //   is not recommended for production code.   //   Interval.QuadPart = (5 * DELAY_ONE_SECOND);   // delay 5 seconds   KeDelayExecutionThread(KernelMode, FALSE, &Interval);

//   // Now go back through the list and delete the device objects.   // 现在回到且遍历列表且删除设备对象   //   for (i=0; i < NumDevices; i++)   {    //    // See if this is our control device object.  If not then cleanup    // the device extension.  If so then clear the global pointer    // that references it.    // 看是否我们的控制设备对象。如果不是那么清除设备扩展。如果是清除引用它的全局指针。    //    if (NULL != DevList[i]->DeviceExtension)     SfCleanupMountedDevice(DevList[i]);    else    {     ASSERT(DevList[i] == gSFilterControlDeviceObject);     gSFilterControlDeviceObject = NULL;    }

//    // Delete the device object, remove reference counts added by    // IoEnumerateDeviceObjectList.  Note that the delete does    // not actually occur until the reference count goes to zero.    // 删除设备对象，删除由IoEnumerateDeviceObjectList增加的引用计数。    // 注意删除直到引用计数降到0时才真正发生    //    IoDeleteDevice(DevList[i]);    ObDereferenceObject(DevList[i]);   }  }

//  // Free our FastIO table  // 释放我们的FastIO表  //  FastIoDispatch = DriverObject->FastIoDispatch;  DriverObject->FastIoDispatch = NULL;  ExFreePool(FastIoDispatch);

ExDeletePagedLookasideList(&gFsCtxLookAsideList);  ExDeletePagedLookasideList(&gFileNameLookAsideList);  ExDeleteNPagedLookasideList(&gReadWriteCompletionCtxLookAsideList);

ZwClose(gRuleFileHandle);  ExDeleteResourceLite(&gRulesResource);  if (gRules)   ExFreePoolWithTag(gRules, SFLT_POOL_TAG); } #endif

#if WINVER >= 0x0501 VOID SfLoadDynamicFunctions (  ) /*++

Routine Description:

// 试图载入不是所有操作系统都支持的例程的函数指针。  // 这些函数指针然后被存储于全局结构SpyDynamicFunctions中  This routine tries to load the function pointers for the routines that  are not supported on all versions of the OS.  These function pointers are  then stored in the global structure SpyDynamicFunctions.

This support allows for one driver to be built that will run on all  versions of the OS Windows 2000 and greater.  Note that on Windows 2000,  the functionality may be limited.   Arguments:

None.   Return Value:

None.

--*/ {  UNICODE_STRING FunctionName;

RtlZeroMemory(&gSfDynamicFunctions, sizeof(gSfDynamicFunctions));

//  // For each routine that we would want to use, lookup its address in the  // kernel or hal.  If it is not present, that field in our global  // SpyDynamicFunctions structure will be set to NULL.  // 对于每个我们想使用的例程，在kernel或HAL中查找他的地址。  // 如果不存在，在我们的SpyDynamicFunctions结构中的那个字段将被设置为NULL。  //

RtlInitUnicodeString(&FunctionName, L"FsRtlRegisterFileSystemFilterCallbacks");  gSfDynamicFunctions.RegisterFileSystemFilterCallbacks = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"IoAttachDeviceToDeviceStackSafe");  gSfDynamicFunctions.AttachDeviceToDeviceStackSafe = MmGetSystemRoutineAddress(&FunctionName);    RtlInitUnicodeString(&FunctionName, L"IoEnumerateDeviceObjectList");  gSfDynamicFunctions.EnumerateDeviceObjectList = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"IoGetLowerDeviceObject");  gSfDynamicFunctions.GetLowerDeviceObject = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"IoGetDeviceAttachmentBaseRef");  gSfDynamicFunctions.GetDeviceAttachmentBaseRef = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"IoGetDiskDeviceObject");  gSfDynamicFunctions.GetDiskDeviceObject = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"IoGetAttachedDeviceReference");  gSfDynamicFunctions.GetAttachedDeviceReference = MmGetSystemRoutineAddress(&FunctionName);

RtlInitUnicodeString(&FunctionName, L"RtlGetVersion");  gSfDynamicFunctions.GetVersion = MmGetSystemRoutineAddress(&FunctionName); }

VOID SfGetCurrentVersion (  ) /*++

Routine Description:       // 基于可用的正确的例程读当前的OS版本  This routine reads the current OS version using the correct routine based  on what routine is available.

Arguments:

None.   Return Value:

None.

--*/ {  if (NULL != gSfDynamicFunctions.GetVersion)  {   RTL_OSVERSIONINFOW VersionInfo;   NTSTATUS Status;

//   // VERSION NOTE: RtlGetVersion does a bit more than we need, but   // we are using it if it is available to show how to use it.  It   // is available on Windows XP and later.  RtlGetVersion and   // RtlVerifyVersionInfo (both documented in the IFS Kit docs) allow   // you to make correct choices when you need to change logic based   // on the current OS executing your code.   //  RtlGetVersion执行多于我们需要的事情，但如果可用我们使用它以显示如何使用它。   //  RtlGetVersion和RtlVerifyVersionInfo允许我们当基于当前OS执行你的代码时执行正确的选择   //   VersionInfo.dwOSVersionInfoSize = sizeof(RTL_OSVERSIONINFOW);

Status = (gSfDynamicFunctions.GetVersion)(&VersionInfo);

ASSERT(NT_SUCCESS(Status));

gSfOsMajorVersion = VersionInfo.dwMajorVersion;   gSfOsMinorVersion = VersionInfo.dwMinorVersion;    }  else  {   PsGetVersion(&gSfOsMajorVersion,    &gSfOsMinorVersion,    NULL,    NULL    );  } } #endif

VOID SfFsNotification(  IN PDEVICE_OBJECT DeviceObject,  IN BOOLEAN FsActive  ) /*++

Routine Description:

// 当一个文件系统或者被登记或者取消登记自己作为一个活动文件系统时被调用  This routine is invoked whenever a file system has either registered or  unregistered itself as an active file system.

For the former case, this routine creates a device object and attaches it  to the specified file system's device object.  This allows this driver  to filter all requests to that file system.  Specifically we are looking  for MOUNT requests so we can attach to newly mounted volumes.  // 对于前者，这个历程创建一个设备对象且附着它到指定文件系统的设备对象。  // 这允许这个驱动过滤到那个文件系统的所有请求。尤其是我们查找MOUNT请求，  // 因而我们可以附着到新安装的卷上

For the latter case, this file system's device object is located,  detached, and deleted.  This removes this file system as a filter for  the specified file system.  // 对于后者，这个文件系统的设备对象被定位，断开且删除。  // 这删除这个文件系统作为特定文件系统的过滤器

Arguments:

// 文件系统设备对象的指针  DeviceObject - Pointer to the file system's device object.

// 布尔值指示是否文件系统已经登记(TRUE)或者取消登记(FALSE)自己作为一个活动的文件系统  FsActive - Boolean indicating whether the file system has registered   (TRUE) or unregistered (FALSE) itself as an active file system.

Return Value:

None.

--*/ {  UNICODE_STRING Name;  WCHAR NameBuffer[MAX_DEVNAME_LENGTH];

PAGED_CODE();

//  // Init local Name buffer  //  RtlInitEmptyUnicodeString(&Name, NameBuffer, sizeof(NameBuffer));

SfGetObjectName(DeviceObject, &Name);

//  // Display the names of all the file system we are notified of  // 显示我们被通知的所有文件系统的名字  //  SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,   ("SFilter!SfFsNotification:     %s %p /"%wZ/" (%s)/n",   (FsActive) ? "Activating file system  " : "Deactivating file system",   DeviceObject,   &Name,   GET_DEVICE_TYPE_NAME(DeviceObject->DeviceType))   );

//  // Handle attaching/detaching from the given file system.  // 处理附着/断开给定文件系统  //  if (FsActive)   SfAttachToFileSystemDevice(DeviceObject, &Name);  else   SfDetachFromFileSystemDevice(DeviceObject); }

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //    IRP Handling Routines // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

NTSTATUS SfPassThrough(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

This routine is the main dispatch routine for the general purpose file  system driver.  It simply passes requests onto the next driver in the  stack, which is presumably a disk file system.

Arguments:

DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

Return Value:

The function value is the status of the operation.

Note:

A note to file system filter implementers:    This routine actually "passes" through the request by taking this   driver out of the IRP stack.  If the driver would like to pass the   I/O request through, but then also see the result, then rather than   taking itself out of the loop it could keep itself in by copying the   caller's parameters to the next stack location and then set its own   completion routine.    这个例程通过将这个驱动取出IRP堆栈而真正传递请求，如果驱动想传递I/O请求，   但是想看到结果，那么就不是将自己取出而是通过拷贝调用者的参数到下层堆栈的   方式保持自己处于堆栈中，且然后设置它自己的完成例程。

Hence, instead of calling: // 因此，不用      IoSkipCurrentIrpStackLocation(Irp);

You could instead call:  // 而是使用

IoCopyCurrentIrpStackLocationToNext(Irp);    IoSetCompletionRoutine(Irp, NULL, NULL, FALSE, FALSE, FALSE);

This example actually NULLs out the caller's I/O completion routine, but   this driver could set its own completion routine so that it would be   notified when the request was completed (see SfCreate for an example of   this).   这个例子真正将调用者的I/O完成例程置NULL，但这个驱动可以设置他自己的完成例程   因此当请求完成时它将被通知。

--*/ {  //  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  //  ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//  // Get this driver out of the driver stack and get to the next driver as  // quickly as possible.  // 将这个驱动取出驱动堆栈且尽快到下层驱动  //  IoSkipCurrentIrpStackLocation(Irp);    //  // Call the appropriate file system driver with the request.  // 按请求调用合适的文件系统驱动  //  return IoCallDriver(((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject, Irp); }

NTSTATUS SfCreate(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:     // 这个函数处理创建/打开操作。它简单地建立一个I/O完成例程在操作成功时被调用     This function filters create/open operations.  It simply establishes an     I/O completion routine to be invoked if the operation was successful.

Arguments:

DeviceObject - Pointer to the target device object of the create/open.

Irp - Pointer to the I/O Request Packet that represents the operation.

Return Value:

The function value is the status of the call to the file system's entry     point.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  PFILE_OBJECT RelatedFileObject = FileObject->RelatedFileObject;  PWSTR FileName = NULL;  PFILE_CONTEXT FileCtxPtr = NULL;  BOOLEAN DeleteOnClose = (BOOLEAN) (IrpSp->Parameters.Create.Options & FILE_DELETE_ON_CLOSE);  BOOLEAN IsEncryptFlagExist = FALSE;  BOOLEAN IsNeedEncrypt = FALSE;  NTSTATUS Status = STATUS_SUCCESS;  NTSTATUS LocalStatus = STATUS_SUCCESS;

PAGED_CODE();

//  // If this is for our control device object, don't allow it to be opened.  // 如果这是我们的控制设备对象，不允许它被打开  //  if (IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject))  {   //   // Sfilter doesn't allow for any communication through its control   // device object, therefore it fails all requests to open a handle   // to its control device object.   //   // See the FileSpy sample for an example of how to allow creates to   // the filter's control device object and manage communication via   // that handle.   // Sfilter不允许通过它的控制设备对象进行任何通讯，因此它失败打开他的控制设备对象的句柄         // 的任何请求，看FileSpy例子知道如何允许过滤控制设备对象的创建及通过句柄管理通讯   //   Irp->IoStatus.Status = STATUS_INVALID_DEVICE_REQUEST;   Irp->IoStatus.Information = 0;   IoCompleteRequest(Irp, IO_NO_INCREMENT);

return STATUS_INVALID_DEVICE_REQUEST;  }

ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//  // We only care about volume filter device object  // 我们仅关心卷过滤设备对象  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

if (DevExt->DriveLetter == L'/0') {

UNICODE_STRING DosName;

Status = SfVolumeDeviceNameToDosName(&DevExt->DeviceName, &DosName);   if (NT_SUCCESS(Status)) {

DevExt->DriveLetter = DosName.Buffer[0];    ExFreePool(DosName.Buffer);      if ((DevExt->DriveLetter >= L'a') && (DevExt->DriveLetter <= L'z')) {     DevExt->DriveLetter += L'A' - L'a';    }   } else {    KdPrint(("sfilter!SfCreate: SfVolumeDeviceNameToDosName(%x) failed(%x)/n",     DevExt->StorageStackDeviceObject, Status));   }  }

//  // Open Volume Device directly  // 直接打开卷设备  //  if ((FileObject->FileName.Length == 0) && !RelatedFileObject)  {   // 打开卷设备时，卷设备对象肯定没有打开，所以必须FileObject->FileName.Length == 0   // 且RelatedFileObject == NULL。   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

do  {   // KdPrint(("sfilter!SfCreate: Entering.../n"));   //   // If the file is opened by id, then we can't get file name directly,   // But if this case happened, the FsContext must be in GenericTable already.   // So we just update the RefCount, that's enough   //   if (!(IrpSp->Parameters.Create.Options & FILE_OPEN_BY_FILE_ID))   {    FileName = ExAllocateFromPagedLookasideList(&gFileNameLookAsideList);    if (!FileName)    {     KdPrint(("sfilter!SfCreate: ExAllocatePoolWithTag failed/n"));

Status = STATUS_INSUFFICIENT_RESOURCES;     break;    }

if (!SfDissectFileName(DeviceObject, Irp, FileName))    {     KdPrint(("sfilter!SfCreate: SfDissectFileName failed/n"));         Status = STATUS_INVALID_PARAMETER;     break;    }

if (wcslen(FileName) >= SF_ENCRYPT_POSTFIX_LENGTH)    {     if (_wcsnicmp(&FileName[wcslen(FileName) - SF_ENCRYPT_POSTFIX_LENGTH],      SF_ENCRYPT_POSTFIX, SF_ENCRYPT_POSTFIX_LENGTH) == 0)     {      //      // We deny all create request to our encrypt falg file except kernel mode      //      if (KernelMode == Irp->RequestorMode)      {       ExFreeToPagedLookasideList(&gFileNameLookAsideList, FileName);

IoSkipCurrentIrpStackLocation(Irp);       return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);      }      else      {       Status = STATUS_SUCCESS;       break;      }     }    }   }

FileCtxPtr = ExAllocatePoolWithTag(PagedPool, sizeof(FILE_CONTEXT), SFLT_POOL_TAG);   if (FileCtxPtr == NULL)   {    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

Status = SfForwardIrpSyncronously(DevExt->AttachedToDeviceObject, Irp);   if (NT_SUCCESS(Status) && (STATUS_REPARSE != Status) && SfIsObjectFile(FileObject))   {    PFILE_CONTEXT FileCtxPtr2 = NULL;    BOOLEAN NewElement = FALSE;

FileCtxPtr->FsContext = FileObject->FsContext;

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);

FileCtxPtr2 = RtlLookupElementGenericTable(&DevExt->FsCtxTable, FileCtxPtr);    if (FileCtxPtr2)     ++FileCtxPtr2->RefCount;    else    {     FileCtxPtr2 = RtlInsertElementGenericTable(      &DevExt->FsCtxTable,      FileCtxPtr,      sizeof(FILE_CONTEXT),      &NewElement      );

FileCtxPtr2->RefCount = 1;

ASSERT(FileName);     wcscpy(FileCtxPtr2->Name, FileName);

KeInitializeEvent(&FileCtxPtr2->Event, SynchronizationEvent, TRUE);    }

FileCtxPtr2->DeleteOnClose = DeleteOnClose;

ExReleaseFastMutex(&DevExt->FsCtxTableMutex);

IsEncryptFlagExist = FALSE;    IsNeedEncrypt = FALSE;    LocalStatus = STATUS_SUCCESS;

KdPrint(("sfilter!SfCreate: FileName = %ws/n", FileCtxPtr2->Name));

//    // we need handle file synchronously    //    KeWaitForSingleObject(&FileCtxPtr2->Event, Executive, KernelMode, FALSE, NULL);       LocalStatus = SfIsEncryptFlagExist(DeviceObject, FileCtxPtr2->Name, &IsEncryptFlagExist,     FileCtxPtr2->EncryptExtData, sizeof(FileCtxPtr2->EncryptExtData));    if (!NT_SUCCESS(LocalStatus))     KdPrint(("sfilter!SfPostCreateWorker: SfIsEncryptFlagExist failed, return %x/n", LocalStatus));       LocalStatus = SfIsFileNeedEncrypt(DeviceObject, FileCtxPtr2->Name, &IsNeedEncrypt);    if (!NT_SUCCESS(LocalStatus))     KdPrint(("sfilter!SfPostCreateWorker: SfIsFileNeedEncrypt failed, return %x/n", LocalStatus));      FileCtxPtr2->EncryptFlagExist = IsEncryptFlagExist;    FileCtxPtr2->NeedEncrypt = IsNeedEncrypt;

KdPrint(("sfilter!SfCreate: IsEncryptFlagExist = %d, IsNeedEncrypt = %d, NewElement = %d/n",     IsEncryptFlagExist, IsNeedEncrypt, NewElement));

if (NewElement && ((!IsNeedEncrypt && IsEncryptFlagExist) || (IsNeedEncrypt && !IsEncryptFlagExist)))    {     if (!IsNeedEncrypt && IsEncryptFlagExist)     {      if (NewElement)       FileCtxPtr2->DecryptOnRead = TRUE;

FileCtxPtr2->EncryptOnWrite = FALSE;           KdPrint(("sfilter!SfPostCreateWorker: Decrypt %ws/n", FileCtxPtr2->Name));      LocalStatus = SfUpdateFileByFileObject(DeviceObject, FileObject);      if (NT_SUCCESS(LocalStatus))      {       FileCtxPtr2->DecryptOnRead = FALSE;       FileCtxPtr2->EncryptOnWrite = FALSE;          LocalStatus = SfSetFileEncrypted(DeviceObject, FileCtxPtr2->Name, FALSE, NULL, 0);       if (NT_SUCCESS(LocalStatus))        FileCtxPtr2->EncryptFlagExist = FALSE;       else        KdPrint(("sfilter!SfPostCreateWorker: SfSetFileEncrypted(%ws, FALSE) failed, return %x/n", FileCtxPtr2->Name, LocalStatus));      }      else      {       KdPrint(("sfilter!SfPostCreateWorker: SfUpdateFileByFileObject failed, return %x/n", LocalStatus));          FileCtxPtr2->DecryptOnRead = TRUE;       FileCtxPtr2->EncryptOnWrite = TRUE;      }     }     else     {      if (NewElement)       FileCtxPtr2->DecryptOnRead = FALSE;

FileCtxPtr2->EncryptOnWrite = TRUE;

KdPrint(("sfilter!SfPostCreateWorker: Encrypt %ws/n", FileCtxPtr2->Name));      LocalStatus = SfUpdateFileByFileObject(DeviceObject, FileObject);      if (NT_SUCCESS(LocalStatus))      {       FileCtxPtr2->DecryptOnRead = TRUE;       FileCtxPtr2->EncryptOnWrite = TRUE;          LocalStatus = SfSetFileEncrypted(DeviceObject, FileCtxPtr2->Name, TRUE,        FileCtxPtr2->EncryptExtData, sizeof(FileCtxPtr2->EncryptExtData));       if (NT_SUCCESS(LocalStatus))        FileCtxPtr2->EncryptFlagExist = TRUE;       else        KdPrint(("sfilter!SfPostCreateWorker: SfSetFileEncrypted(%ws, TRUE) failed, return %x/n", FileCtxPtr2->Name, LocalStatus));      }      else      {       KdPrint(("sfilter!SfPostCreateWorker: SfUpdateFileByFileObject failed, return %x/n", LocalStatus));          FileCtxPtr2->DecryptOnRead = FALSE;       FileCtxPtr2->EncryptOnWrite = FALSE;      }               }    }    else    {     if (FileCtxPtr2->NeedEncrypt)     {      FileCtxPtr2->DecryptOnRead = TRUE;      FileCtxPtr2->EncryptOnWrite = TRUE;

if (!FileCtxPtr2->EncryptFlagExist)      {       LocalStatus = SfSetFileEncrypted(DeviceObject, FileCtxPtr2->Name, TRUE,        FileCtxPtr2->EncryptExtData, sizeof(FileCtxPtr2->EncryptExtData));       if (NT_SUCCESS(LocalStatus))        FileCtxPtr2->EncryptFlagExist = TRUE;       else        KdPrint(("sfilter!SfPostCreateWorker: SfSetFileEncrypted(%ws, TRUE) failed, return %x/n", FileCtxPtr2->Name, LocalStatus));      }         }     else     {      FileCtxPtr2->DecryptOnRead = FALSE;      FileCtxPtr2->EncryptOnWrite = FALSE;

if (FileCtxPtr2->EncryptFlagExist)      {       LocalStatus = SfSetFileEncrypted(DeviceObject, FileCtxPtr2->Name, FALSE,        NULL, 0);       if (NT_SUCCESS(LocalStatus))        FileCtxPtr2->EncryptFlagExist = FALSE;       else        KdPrint(("sfilter!SfPostCreateWorker: SfSetFileEncrypted(%ws, TRUE) failed, return %x/n", FileCtxPtr2->Name, LocalStatus));      }         }    }       KeSetEvent(&FileCtxPtr2->Event, IO_NO_INCREMENT, FALSE);   }  } while (FALSE);

// 释放名字控制结构     // Release the name control structure if we have  if (FileName)   ExFreeToPagedLookasideList(&gFileNameLookAsideList, FileName);

if (FileCtxPtr)   ExFreePool(FileCtxPtr);

// 保存状态且继续处理IRP     // Save the status and continue processing the IRP     // KdPrint(("sfilter!SfCreate: Exiting.../n"));  Irp->IoStatus.Status = Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);

return Status; }

NTSTATUS SfCleanup(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

当一个清除或者关闭请求被处理时被调用。注意：这个例程不真正执行东西，它与SfPassThrough相同  它仅登记作为清除处理器以使调试更加容易（你可以在这里设置断点从而代替在通用的PassThrough设置断点）     This routine is invoked whenever a cleanup or a close request is to be     processed. NOTE: This routine doesn't actually do anything, it is the same     as SfPassThrough. It is only registered as the cleanup handler to ease in     debugging (You can set a Breakpoint here instead of in the generic PassThrough.

Arguments:

DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

Return Value:

The function value is the status of the operation.

Note:

See notes for SfPassThrough for this routine.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  FILE_CONTEXT_HDR FileCtxHdr;  PFILE_CONTEXT FileCtxPtr = NULL;  BOOLEAN DeletePending = FileObject->DeletePending;  BOOLEAN DeleteOnClose = FALSE;  NTSTATUS Status;

PAGED_CODE();

//  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  //   ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

FileCtxHdr.FsContext = FileObject->FsContext;

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);  FileCtxPtr = RtlLookupElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);  ExReleaseFastMutex(&DevExt->FsCtxTableMutex);

if (!FileCtxPtr)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

KeWaitForSingleObject(&FileCtxPtr->Event, Executive, KernelMode, FALSE, NULL);

Status = SfForwardIrpSyncronously(DevExt->AttachedToDeviceObject, Irp);  if (!NT_SUCCESS(Status))  {   KeSetEvent(&FileCtxPtr->Event, IO_NO_INCREMENT, FALSE);   IoCompleteRequest(Irp, IO_NO_INCREMENT);   return Status;  }

DeleteOnClose = FileCtxPtr->DeleteOnClose;  FileCtxPtr->DeleteOnClose = FALSE;

if (DeletePending || DeleteOnClose)  {   if (FileCtxPtr->EncryptFlagExist)   {    NTSTATUS LocalStatus;

LocalStatus = SfSetFileEncrypted(DeviceObject, FileCtxPtr->Name, FALSE, NULL, 0);    if (NT_SUCCESS(LocalStatus))    {     FileCtxPtr->EncryptFlagExist = FALSE;    }    else    {     KdPrint(("sfilter!SfClose: SfSetFileEncrypted failed, return %x/n", LocalStatus));    }   }  }

KeSetEvent(&FileCtxPtr->Event, IO_NO_INCREMENT, FALSE);

IoCompleteRequest(Irp, IO_NO_INCREMENT);  return Status; }

NTSTATUS SfClose(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  FILE_CONTEXT_HDR FileCtxHdr;  PFILE_CONTEXT FileCtxPtr = NULL;

PAGED_CODE();

//  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  //   ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

if (((FileObject->Flags & FO_STREAM_FILE) == FO_STREAM_FILE) ||   (FileObject->SectionObjectPointer &&   (CcGetFileObjectFromSectionPtrs(FileObject->SectionObjectPointer) == FileObject)))  {  }  else  {   FileCtxHdr.FsContext = FileObject->FsContext;

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);   FileCtxPtr = RtlLookupElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);   if (FileCtxPtr)   {    if (FileCtxPtr->RefCount > 0)     --FileCtxPtr->RefCount;

if ((0 == FileCtxPtr->RefCount) &&     (!FileObject->SectionObjectPointer ||     (!FileObject->SectionObjectPointer->DataSectionObject &&     !FileObject->SectionObjectPointer->ImageSectionObject)))    {     RtlDeleteElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);    }   }   ExReleaseFastMutex(&DevExt->FsCtxTableMutex);  }

IoSkipCurrentIrpStackLocation(Irp);  return IoCallDriver(DevExt->AttachedToDeviceObject, Irp); }

NTSTATUS SfRead(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  PREAD_WRITE_COMPLETION_CONTEXT CompletionCtx = NULL;  PVOID OldBuffer = NULL;  PMDL Mdl = NULL;  PVOID MyBuffer = NULL;  ULONG Length = 0;  FILE_CONTEXT_HDR FileCtxHdr;  PFILE_CONTEXT FileCtxPtr = NULL;  NTSTATUS Status = STATUS_SUCCESS;    PAGED_CODE();

//  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  //   ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif    if (!(Irp->Flags & (IRP_NOCACHE | IRP_PAGING_IO | IRP_SYNCHRONOUS_PAGING_IO)))  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);    FileCtxHdr.FsContext = FileObject->FsContext;  FileCtxPtr = RtlLookupElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);    ExReleaseFastMutex(&DevExt->FsCtxTableMutex);    if (!FileCtxPtr || !FileCtxPtr->DecryptOnRead)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

do  {   Length = IrpSp->Parameters.Read.Length;

if (Irp->MdlAddress)   {    OldBuffer = MmGetSystemAddressForMdl(Irp->MdlAddress);   }   else   {    Mdl = IoAllocateMdl(Irp->UserBuffer, Length, FALSE, FALSE, NULL);    if (Mdl == NULL)    {     KdPrint(("sfilter!SfRead: IoAllocateMdl failed/n"));     Status = STATUS_INSUFFICIENT_RESOURCES;     break;    }

try          {              MmProbeAndLockPages(Mdl, Irp->RequestorMode, IoWriteAccess);          }          except (EXCEPTION_EXECUTE_HANDLER)          {     KdPrint(("sfilter!SfRead: STATUS_INVALID_USER_BUFFER/n"));     IoFreeMdl(Mdl);     Status = STATUS_INVALID_USER_BUFFER;     break;          }

OldBuffer = MmGetSystemAddressForMdl(Mdl);   }

if (!OldBuffer)   {    KdPrint(("sfilter!SfRead: STATUS_INVALID_PARAMETER/n"));    if (Mdl)    {     MmUnlockPages(Mdl);     IoFreeMdl(Mdl);    }    Status = STATUS_INVALID_PARAMETER;    break;   }

CompletionCtx = ExAllocateFromNPagedLookasideList(&gReadWriteCompletionCtxLookAsideList);   if (!CompletionCtx)   {    KdPrint(("sfilter!SfRead: STATUS_INSUFFICIENT_RESOURCES/n"));    if (Mdl)    {     MmUnlockPages(Mdl);     IoFreeMdl(Mdl);    }    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

MyBuffer = ExAllocatePoolWithTag(NonPagedPool, IrpSp->Parameters.Write.Length, SFLT_POOL_TAG);   if (!MyBuffer)   {    KdPrint(("sfilter!SfRead: STATUS_INSUFFICIENT_RESOURCES/n"));    if (Mdl)    {     MmUnlockPages(Mdl);     IoFreeMdl(Mdl);    }    ExFreePool(CompletionCtx);    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

CompletionCtx->OldMdl = Irp->MdlAddress;   CompletionCtx->OldUserBuffer = Irp->UserBuffer;   CompletionCtx->OldSystemBuffer = Irp->AssociatedIrp.SystemBuffer;

CompletionCtx->MdlForUserBuffer = Mdl;

CompletionCtx->OldBuffer = OldBuffer;   CompletionCtx->MyBuffer = MyBuffer;   CompletionCtx->Length = Length;

Irp->MdlAddress = IoAllocateMdl(MyBuffer, IrpSp->Parameters.Write.Length, FALSE, TRUE, NULL);   if (!Irp->MdlAddress)   {    KdPrint(("sfilter!SfRead: STATUS_INSUFFICIENT_RESOURCES/n"));    Irp->MdlAddress = CompletionCtx->OldMdl;    if (Mdl)    {     MmUnlockPages(Mdl);     IoFreeMdl(Mdl);    }    ExFreePool(CompletionCtx);    ExFreePool(MyBuffer);    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

KdPrint(("sfilter!SfRead: Decrypt %ws/n", FileCtxPtr->Name));     MmBuildMdlForNonPagedPool(Irp->MdlAddress);   Irp->UserBuffer = MmGetMdlVirtualAddress(Irp->MdlAddress);

IoCopyCurrentIrpStackLocationToNext(Irp);   IoSetCompletionRoutine(Irp, SfReadCompletion, CompletionCtx, TRUE, TRUE,TRUE);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);

} while (FALSE);

Irp->IoStatus.Status = Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);    return Status; }

NTSTATUS SfReadCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  ) {  PREAD_WRITE_COMPLETION_CONTEXT CompletionCtx = (PREAD_WRITE_COMPLETION_CONTEXT) Context;  ULONG Offset = 0;

UNREFERENCED_PARAMETER(DeviceObject);

if (Irp->PendingReturned)   IoMarkIrpPending(Irp);

IoFreeMdl(Irp->MdlAddress);

Irp->MdlAddress = CompletionCtx->OldMdl;  Irp->UserBuffer = CompletionCtx->OldUserBuffer;  Irp->AssociatedIrp.SystemBuffer = CompletionCtx->OldSystemBuffer;

// decrypt  for (Offset = 0; Offset < CompletionCtx->Length; ++Offset)  {   ((PUCHAR) CompletionCtx->OldBuffer)[Offset] = ~((PUCHAR) CompletionCtx->MyBuffer)[Offset];  }

if (CompletionCtx->MdlForUserBuffer)  {   MmUnlockPages(CompletionCtx->MdlForUserBuffer);   IoFreeMdl(CompletionCtx->MdlForUserBuffer);  }

ExFreePoolWithTag(CompletionCtx->MyBuffer, SFLT_POOL_TAG);  ExFreeToNPagedLookasideList(&gReadWriteCompletionCtxLookAsideList, CompletionCtx);

return STATUS_SUCCESS; }

NTSTATUS SfWrite(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  FILE_CONTEXT_HDR FileCtxHdr;  PFILE_CONTEXT FileCtxPtr = NULL;  PREAD_WRITE_COMPLETION_CONTEXT CompletionCtx = NULL;  PVOID OldBuffer = NULL;  PVOID MyBuffer = NULL;  ULONG Length = 0;  ULONG Offset = 0;  NTSTATUS Status = STATUS_SUCCESS;

PAGED_CODE();

//  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  //  ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

if (!(Irp->Flags & (IRP_NOCACHE | IRP_PAGING_IO | IRP_SYNCHRONOUS_PAGING_IO)))  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);    FileCtxHdr.FsContext = FileObject->FsContext;  FileCtxPtr = RtlLookupElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);    ExReleaseFastMutex(&DevExt->FsCtxTableMutex);    if (!FileCtxPtr || !FileCtxPtr->EncryptOnWrite)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

do  {   Length = IrpSp->Parameters.Write.Length;

if (Irp->MdlAddress)   {    OldBuffer = MmGetSystemAddressForMdl(Irp->MdlAddress);   }   else   {    PMDL Mdl;

Mdl = IoAllocateMdl(Irp->UserBuffer, Length, FALSE, FALSE, NULL);    if (Mdl == NULL)    {     KdPrint(("sfilter!SfWrite: IoAllocateMdl failed/n"));     Status = STATUS_INSUFFICIENT_RESOURCES;     break;    }

try          {              MmProbeAndLockPages(Mdl, Irp->RequestorMode, IoReadAccess);          }          except (EXCEPTION_EXECUTE_HANDLER)          {     KdPrint(("sfilter!SfWrite: STATUS_INVALID_USER_BUFFER/n"));     IoFreeMdl(Mdl);     Status = STATUS_INVALID_USER_BUFFER;     break;          }

MmUnlockPages(Mdl);    IoFreeMdl(Mdl);

OldBuffer = Irp->UserBuffer;   }

if (!OldBuffer)   {    KdPrint(("sfilter!SfWrite: STATUS_INVALID_PARAMETER/n"));    Status = STATUS_INVALID_PARAMETER;    break;   }

CompletionCtx = ExAllocateFromNPagedLookasideList(&gReadWriteCompletionCtxLookAsideList);   if (!CompletionCtx)   {    KdPrint(("sfilter!SfWrite: STATUS_INSUFFICIENT_RESOURCES/n"));    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

MyBuffer = ExAllocatePoolWithTag(NonPagedPool, IrpSp->Parameters.Write.Length, SFLT_POOL_TAG);   if (!MyBuffer)   {    KdPrint(("sfilter!SfWrite: STATUS_INSUFFICIENT_RESOURCES/n"));    ExFreePool(CompletionCtx);    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

CompletionCtx->OldMdl = Irp->MdlAddress;   CompletionCtx->OldUserBuffer = Irp->UserBuffer;   CompletionCtx->OldSystemBuffer = Irp->AssociatedIrp.SystemBuffer;

CompletionCtx->MdlForUserBuffer = NULL;

CompletionCtx->OldBuffer = OldBuffer;   CompletionCtx->MyBuffer = MyBuffer;   CompletionCtx->Length = Length;

Irp->MdlAddress = IoAllocateMdl(MyBuffer, IrpSp->Parameters.Write.Length, FALSE, TRUE, NULL);   if (!Irp->MdlAddress)   {    KdPrint(("sfilter!SfWrite: STATUS_INSUFFICIENT_RESOURCES/n"));    Irp->MdlAddress = CompletionCtx->OldMdl;    ExFreePool(CompletionCtx);    ExFreePool(MyBuffer);    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

KdPrint(("sfilter!SfWrite: Encrypt %ws/n", FileCtxPtr->Name));     // encrypt   for (Offset = 0; Offset < Length; ++Offset)   {    ((PUCHAR) MyBuffer)[Offset] = ~((PUCHAR) OldBuffer)[Offset];   }

MmBuildMdlForNonPagedPool(Irp->MdlAddress);   Irp->UserBuffer = MmGetMdlVirtualAddress(Irp->MdlAddress);

IoCopyCurrentIrpStackLocationToNext(Irp);   IoSetCompletionRoutine(Irp, SfWriteCompletion, CompletionCtx, TRUE, TRUE,TRUE);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);

} while (FALSE);

Irp->IoStatus.Status = Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);    return Status; }

NTSTATUS SfWriteCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  ) {  PREAD_WRITE_COMPLETION_CONTEXT CompletionCtx = (PREAD_WRITE_COMPLETION_CONTEXT) Context;  ULONG Offset = 0;

UNREFERENCED_PARAMETER(DeviceObject);

if (Irp->PendingReturned)   IoMarkIrpPending(Irp);

IoFreeMdl(Irp->MdlAddress);

Irp->MdlAddress = CompletionCtx->OldMdl;  Irp->UserBuffer = CompletionCtx->OldUserBuffer;  Irp->AssociatedIrp.SystemBuffer = CompletionCtx->OldSystemBuffer;

ExFreePoolWithTag(CompletionCtx->MyBuffer, SFLT_POOL_TAG);  ExFreeToNPagedLookasideList(&gReadWriteCompletionCtxLookAsideList, CompletionCtx);

return STATUS_SUCCESS; }

NTSTATUS SfDirectoryControl(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  NTSTATUS Status = STATUS_SUCCESS;  PFILE_BOTH_DIR_INFORMATION DirInfo = NULL;  PFILE_BOTH_DIR_INFORMATION PreDirInfo = NULL;  ULONG Length = 0;  ULONG NewLength = 0;  ULONG Offset = 0;  ULONG CurPos = 0;

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

if (IrpSp->MinorFunction != IRP_MN_QUERY_DIRECTORY)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

if (IrpSp->Parameters.QueryDirectory.FileInformationClass != FileBothDirectoryInformation)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }    Status = SfForwardIrpSyncronously(DevExt->AttachedToDeviceObject, Irp);

while (TRUE)  {   if (!NT_SUCCESS(Status))    break;

Length = IrpSp->Parameters.QueryDirectory.Length;   NewLength = Length;   CurPos = 0;   DirInfo = (PFILE_BOTH_DIR_INFORMATION) Irp->UserBuffer;   PreDirInfo = DirInfo;

//   // There is no entry, so just complete the request   //   if (Length == 0)    break;

//   // Sanity check   //   if ((!DirInfo) || (DirInfo->NextEntryOffset > Length))    break;     do   {    Offset = DirInfo->NextEntryOffset;

if ((DirInfo->FileNameLength > SF_ENCRYPT_POSTFIX_LENGTH * sizeof(WCHAR)) &&     (_wcsnicmp(&DirInfo->FileName[DirInfo->FileNameLength / sizeof(WCHAR) - SF_ENCRYPT_POSTFIX_LENGTH],      SF_ENCRYPT_POSTFIX, SF_ENCRYPT_POSTFIX_LENGTH) == 0))    {     if (0 == Offset) // the last one     {      PreDirInfo->NextEntryOffset = 0;      NewLength = CurPos;     }     else     {      if (PreDirInfo != DirInfo)      {       PreDirInfo->NextEntryOffset += DirInfo->NextEntryOffset;       DirInfo = (PFILE_BOTH_DIR_INFORMATION) ((PUCHAR) DirInfo + Offset);      }      else      {       RtlMoveMemory((PUCHAR) DirInfo,(PUCHAR) DirInfo + Offset, Length - CurPos - Offset);       NewLength -= Offset;      }     }     }     else     {     CurPos += Offset;     PreDirInfo = DirInfo;     DirInfo = (PFILE_BOTH_DIR_INFORMATION) ((PUCHAR) DirInfo + Offset);    }   } while (0 != Offset);

if (0 == NewLength) // All entry is filtered   {    Status = SfForwardIrpSyncronously(DevExt->AttachedToDeviceObject, Irp);

//    // If no entry returned, just complete the request,    // else we must continue to filter    //    if (0 == Irp->IoStatus.Information)     break;   }   else   {    Irp->IoStatus.Information = NewLength;    break;   }

// continue to filter  }

IoCompleteRequest(Irp, IO_NO_INCREMENT);  return Status; }

NTSTATUS SfSetInformation(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  PFILE_RENAME_INFORMATION RenameInfo = (PFILE_RENAME_INFORMATION) Irp->AssociatedIrp.SystemBuffer;  FILE_CONTEXT_HDR FileCtxHdr;  PFILE_CONTEXT FileCtxPtr = NULL;  PWSTR FileName = NULL;  PWSTR TargetFileName = NULL;  BOOLEAN DecryptOnRead = FALSE;  BOOLEAN EncryptOnWrite = FALSE;  BOOLEAN IsEncryptFlagExist = FALSE;  BOOLEAN IsTargetNeedEncrypt = FALSE;  NTSTATUS Status = STATUS_SUCCESS;  NTSTATUS LocalStatus = STATUS_SUCCESS;

//  // We only care about volume filter device object  //  if (!DevExt->StorageStackDeviceObject)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

#if DBG  if (DevExt->DriveLetter != DEBUG_VOLUME)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  } #endif

if (IrpSp->Parameters.QueryFile.FileInformationClass != FileRenameInformation)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

FileCtxHdr.FsContext = FileObject->FsContext;

ExAcquireFastMutex(&DevExt->FsCtxTableMutex);  FileCtxPtr = RtlLookupElementGenericTable(&DevExt->FsCtxTable, &FileCtxHdr);  ExReleaseFastMutex(&DevExt->FsCtxTableMutex);    if (!FileCtxPtr)  {   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

do  {    FileName = ExAllocateFromPagedLookasideList(&gFileNameLookAsideList);   if (!FileName)   {    KdPrint(("sfilter!SfSetInformation: STATUS_INSUFFICIENT_RESOURCES/n"));    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

TargetFileName = ExAllocateFromPagedLookasideList(&gFileNameLookAsideList);   if (!TargetFileName)   {    KdPrint(("sfilter!SfSetInformation: STATUS_INSUFFICIENT_RESOURCES/n"));    Status = STATUS_INSUFFICIENT_RESOURCES;    break;   }

RtlZeroMemory(FileName, MAX_PATH * sizeof(WCHAR));   RtlZeroMemory(TargetFileName, MAX_PATH * sizeof(WCHAR));

wcscpy(FileName, FileCtxPtr->Name);

if (!IrpSp->Parameters.SetFile.FileObject)   {    //    // Simple rename    //    WCHAR OldChar;    PWCHAR Ptr = NULL;       Ptr = wcsrchr(FileName, L'//');    if (!Ptr)    {     KdPrint(("sfilter!SfSetInformation: Invalid STATUS_INVALID_PARAMETER/n"));     Status = STATUS_INVALID_PARAMETER;     break;    }

++Ptr;    OldChar = *Ptr;    *Ptr = L'/0';    wcscpy(TargetFileName, FileName);    *Ptr = OldChar;    wcsncat(     TargetFileName,     RenameInfo->FileName,     RenameInfo->FileNameLength / sizeof(WCHAR)     );   }   else   {    if (RenameInfo->RootDirectory != NULL)    {     //     // Relative rename     //     WCHAR OldChar;     PWCHAR Ptr = NULL;         Ptr = wcsrchr(FileName, L'//');     if (!Ptr)     {      KdPrint(("sfilter!SfSetInformation: Invalid STATUS_INVALID_PARAMETER/n"));      Status = STATUS_INVALID_PARAMETER;      break;     }

++Ptr;     OldChar = *Ptr;     *Ptr = L'/0';     wcscpy(TargetFileName, FileName);     *Ptr = OldChar;     wcsncat(      TargetFileName,      RenameInfo->FileName,      RenameInfo->FileNameLength / sizeof(WCHAR)      );    }    else    {     //     // Full qualified rename, /??/ , /DosDevices/     //     if (0 == _wcsnicmp(&RenameInfo->FileName[0], L"//??//", 4))     {      wcsncpy(TargetFileName,       &RenameInfo->FileName[4],       (RenameInfo->FileNameLength / sizeof(WCHAR)) - 4       );     }     else if (0 == _wcsnicmp(&RenameInfo->FileName[0], L"//DosDevices//", 12))     {      wcsncpy(TargetFileName,       &RenameInfo->FileName[11],       (RenameInfo->FileNameLength / sizeof(WCHAR)) - 12       );     }     else     {      KdPrint(("sfilter!SfSetInformation: RenameInfo->FileName = %ws/n", RenameInfo->FileName));      ASSERT(FALSE);     }       }   }

KdPrint(("sfilter!SfSetInformation: %ws -> %ws/n", FileCtxPtr->Name, TargetFileName));

KeWaitForSingleObject(&FileCtxPtr->Event, Executive, KernelMode, FALSE, NULL);

Status = SfForwardIrpSyncronously(DevExt->AttachedToDeviceObject, Irp);   if (!NT_SUCCESS(Status))   {    KeSetEvent(&FileCtxPtr->Event, IO_NO_INCREMENT, FALSE);    KdPrint(("sfilter!SfSetInformation: SfForwardIrpSyncronously failed, return %x/n", Status));    break;   }

do   {    wcscpy(FileCtxPtr->Name, TargetFileName);      LocalStatus = SfSetFileEncrypted(DeviceObject, FileName, FALSE, NULL, 0);    if (!NT_SUCCESS(LocalStatus))    {     KdPrint(("sfilter!SfPostSetInformationWorker: SfSetFileEncrypted(%ws, FALSE) failed, return %x/n", FileName, LocalStatus));     ASSERT(FALSE);     break;    }      LocalStatus = SfIsFileNeedEncrypt(DeviceObject, TargetFileName, &IsTargetNeedEncrypt);    if (!NT_SUCCESS(LocalStatus))    {     KdPrint(("sfilter!SfPostSetInformationWorker: SfIsFileNeedEncrypt failed, return %x/n", LocalStatus));     ASSERT(FALSE);     break;    }      DecryptOnRead = FileCtxPtr->DecryptOnRead;    EncryptOnWrite = FileCtxPtr->EncryptOnWrite;    IsEncryptFlagExist = FileCtxPtr->EncryptFlagExist;      FileCtxPtr->NeedEncrypt = IsTargetNeedEncrypt;      if (EncryptOnWrite && !IsTargetNeedEncrypt)    {     FileCtxPtr->EncryptOnWrite = FALSE;

KdPrint(("sfilter!SfPostSetInformationWorker: Decrypt %ws/n", FileCtxPtr->Name));     LocalStatus = SfUpdateFileByFileObject(DeviceObject, FileObject);     if (NT_SUCCESS(LocalStatus))     {      FileCtxPtr->DecryptOnRead = FALSE;      FileCtxPtr->EncryptFlagExist = FALSE;     }     else     {      KdPrint(("sfilter!SfPostSetInformationWorker: SfUpdateFileByFileObject failed, return %x/n", LocalStatus));      ASSERT(FALSE);     }    }    else if (!EncryptOnWrite && IsTargetNeedEncrypt)    {     FileCtxPtr->EncryptOnWrite = TRUE;         KdPrint(("sfilter!SfPostSetInformationWorker: Encrypt %ws/n", FileCtxPtr->Name));     LocalStatus = SfUpdateFileByFileObject(DeviceObject, FileObject);     if (NT_SUCCESS(LocalStatus))     {      FileCtxPtr->DecryptOnRead = TRUE;        LocalStatus = SfSetFileEncrypted(DeviceObject, TargetFileName, TRUE, FileCtxPtr->EncryptExtData, sizeof(FileCtxPtr->EncryptExtData));      if (NT_SUCCESS(LocalStatus))       FileCtxPtr->EncryptFlagExist = TRUE;      else      {       KdPrint(("sfilter!SfPostSetInformationWorker: SfSetFileEncrypted(%ws, TRUE) failed, return %x/n", TargetFileName, LocalStatus));       ASSERT(FALSE);      }     }     else     {      KdPrint(("sfilter!SfPostSetInformationWorker: SfUpdateFileByFileObject failed, return %x/n", LocalStatus));      ASSERT(FALSE);     }    }    else if (IsTargetNeedEncrypt)    {     LocalStatus = SfSetFileEncrypted(DeviceObject, TargetFileName, TRUE, FileCtxPtr->EncryptExtData, sizeof(FileCtxPtr->EncryptExtData));     if (NT_SUCCESS(LocalStatus))      FileCtxPtr->EncryptFlagExist = TRUE;     else     {      KdPrint(("sfilter!SfPostSetInformationWorker: SfSetFileEncrypted(%ws, TRUE) failed, return %x/n", TargetFileName, LocalStatus));      ASSERT(FALSE);     }    }   } while (FALSE);

KeSetEvent(&FileCtxPtr->Event, IO_NO_INCREMENT, FALSE);

} while (FALSE);    if (FileName)   ExFreeToPagedLookasideList(&gFileNameLookAsideList, FileName);

if (TargetFileName)   ExFreeToPagedLookasideList(&gFileNameLookAsideList, TargetFileName);

Irp->IoStatus.Status = Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);  return Status; }

NTSTATUS SfFsControl(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

This routine is invoked whenever an I/O Request Packet (IRP) w/a major  function code of IRP_MJ_FILE_SYSTEM_CONTROL is encountered.  For most  IRPs of this type, the packet is simply passed through.  However, for  some requests, special processing is required.  当遇到w/a主功能码为IRP_MJ_FILE_SYSTEM_CONTROL的I/O请求包时被调用。  对于大多数这个类型的IRPs，包将简单地向下传递。但是，对于一些请求，需要特定处理。

Arguments:

DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

Return Value:

The function value is the status of the operation.

--*/ {  PIO_STACK_LOCATION irpSp = IoGetCurrentIrpStackLocation(Irp);

PAGED_CODE();

//  // Sfilter doesn't allow handles to its control device object to be created,  // therefore, no other operation should be able to come through.  // Sfilter不允许创建他的控制设备对象的句柄，因此，没有其它操作应该能够被通过  //   ASSERT(!IS_MY_CONTROL_DEVICE_OBJECT(DeviceObject));  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//  // Process the minor function code.  //  switch (irpSp->MinorFunction)  {   case IRP_MN_MOUNT_VOLUME:

return SfFsControlMountVolume(DeviceObject, Irp);

case IRP_MN_LOAD_FILE_SYSTEM:

return SfFsControlLoadFileSystem(DeviceObject, Irp);  }

//  // Pass all other file system control requests through.     // 将所有其它文件系统控制请求通过  //  IoSkipCurrentIrpStackLocation(Irp);  return IoCallDriver(((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject, Irp); }

NTSTATUS SfFsControlCompletion(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  ) /*++

Routine Description:

This routine is invoked for the completion of an FsControl request.  It  signals an event used to re-sync back to the dispatch routine.  // FsControl请求完成时被调用。它信号一个事件用于重新同步回分发例程。

Arguments:

DeviceObject - Pointer to this driver's device object that was attached to    the file system device object

Irp - Pointer to the IRP that was just completed.

Context - Pointer to the event to signal

--*/

{  UNREFERENCED_PARAMETER(DeviceObject);  UNREFERENCED_PARAMETER(Irp);

ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));  ASSERT(Context != NULL);

#if WINVER >= 0x0501  if (IS_WINDOWSXP_OR_LATER())  {   //   // On Windows XP or later, the context passed in will be an event   // to signal.   // 在Windows XP or later，传入的上下文中有要信号的事件。   //   KeSetEvent((PKEVENT)Context, IO_NO_INCREMENT, FALSE);  }  else  { #endif   //   // For Windows 2000, if we are not at passive level, we should   // queue this work to a worker thread using the workitem that is in   // Context.   // 对于Windows 2000，如果我们不处于passive级，   // 我们应该使用在上下文中的workitem排队这个工作到一个工作线程   //   if (KeGetCurrentIrql() > PASSIVE_LEVEL)   {    //    // We are not at passive level, but we need to be to do our work,    // so queue off to the worker thread.    //       ExQueueWorkItem((PWORK_QUEUE_ITEM) Context, DelayedWorkQueue);      }   else   {    PWORK_QUEUE_ITEM WorkItem = Context;

//    // We are already at passive level, so we will just call our    // worker routine directly.    // 我们已经在passive级，因此我们直接调用我们的工作例程    //    (WorkItem->WorkerRoutine)(WorkItem->Parameter);   }

#if WINVER >= 0x0501  } #endif

return STATUS_MORE_PROCESSING_REQUIRED; }

NTSTATUS SfFsControlMountVolume(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

This processes a MOUNT VOLUME request.  // 处理卷安装请求

NOTE:  The device object in the MountVolume parameters points    to the top of the storage stack and should not be used.  // 注意：在MountVolume参数中的设备对象指向存储堆栈的顶部且不应该被使用

Arguments:

// 指向我们要附着的卷设备对象  DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

Return Value:

The status of the operation.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt = DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PDEVICE_OBJECT NewDeviceObject;  PDEVICE_OBJECT StorageStackDeviceObject;  PSFILTER_DEVICE_EXTENSION NewDevExt;  NTSTATUS Status;  BOOLEAN IsShadowCopyVolume;  PFSCTRL_COMPLETION_CONTEXT CompletionContext;

PAGED_CODE();

ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));  // 确认是磁盘、光驱、网络文件系统类型  ASSERT(IS_DESIRED_DEVICE_TYPE(DeviceObject->DeviceType));

//  // Get the real device object (also known as the storage stack device  // object or the disk device object) pointed to by the vpb parameter  // because this vpb may be changed by the underlying file system.  // Both FAT and CDFS may change the VPB address if the volume being  // mounted is one they recognize from a previous mount.  // 得到由VPB参数指向的真实设备对象（存储堆栈设备对象或者磁盘设备对象）     // 因为这个VPB可以被下面的文件系统改变。如果被安装的卷是前面安装已经认识的卷     // FAT和CDFS可以改变VPB地址  //  // IrpSp->Parameters.MountVolume.Vpb Pointer to the volume parameter block (VPB) for     // the volume to be mounted. File systems that support removable media might     // substitute a previously used VPB for the one passed in this parameter.     // On such file systems, after the volume is mounted, this pointer can no longer     // be assumed to be valid. File system filter drivers that filter these file systems     // should use this parameter as follows: Before sending the IRP down to lower-level     // drivers, the filter should save the value of IrpSp->Parameters.MountVolume.Vpb->RealDevice.     // After the volume is successfully mounted, the filter can use this pointer to the     // storage device object to obtain the correct VPB pointer     // 支持可移动介质可能替换前面使用的VPB为这个参数传入的VPB。在这样的系统上，     // 在卷被安装后，这个指针不再有效。因此过滤驱动在向下层驱动传递irp前应该保存     // IrpSp->Parameters.MountVolume.Vpb->RealDevice的值。在卷成功安装后，过滤驱动可以     // 使用这个指向存储设备对象的指针得到正确的VPB指针

//  Originating Device (required for workque algorithms) 原始设备  StorageStackDeviceObject = IrpSp->Parameters.MountVolume.Vpb->RealDevice;

//  // Determine if this is a shadow copy volume.  If so don't attach to it.  // NOTE:  There is no reason sfilter shouldn't attach to these volumes,  //  this is simply a sample of how to not attach if you don't want  //  to  // 决定是否这是一个影子拷贝卷。如果是这样，不附着到它，这里是演示如何选择附着卷     // 而不是因为sfilter不应该附着这些卷  //  Status = SfIsShadowCopyVolume(StorageStackDeviceObject,   &IsShadowCopyVolume   );  if (NT_SUCCESS(Status) && IsShadowCopyVolume)  {   //   // Go to the next driver   //   IoSkipCurrentIrpStackLocation(Irp);   return IoCallDriver(DevExt->AttachedToDeviceObject, Irp);  }

//  // This is a mount request.  Create a device object that can be  // attached to the file system's volume device object if this request  // is successful.  We allocate this memory now since we can not return  // an error in the completion routine.   //  // Since the device object we are going to attach to has not yet been  // created (it is created by the base file system) we are going to use  // the type of the file system control device object.  We are assuming  // that the file system control device object will have the same type  // as the volume device objects associated with it.  //

Status = IoCreateDevice(gSFilterDriverObject,    sizeof(SFILTER_DEVICE_EXTENSION),    NULL,    DeviceObject->DeviceType,    0,    FALSE,    &NewDeviceObject    );  if (!NT_SUCCESS(Status))  {   //   // If we can not attach to the volume, then don't allow the volume   // to be mounted.   //   KdPrint(("SFilter!SfFsControlMountVolume: Error creating volume device object, Status=%08x/n", Status));

Irp->IoStatus.Information = 0;   Irp->IoStatus.Status = Status;   IoCompleteRequest(Irp, IO_NO_INCREMENT);

return Status;  }

//  // We need to save the RealDevice object pointed to by the vpb  // parameter because this vpb may be changed by the underlying  // file system.  Both FAT and CDFS may change the VPB address if  // the volume being mounted is one they recognize from a previous  // mount.  //  NewDevExt = NewDeviceObject->DeviceExtension;

RtlZeroMemory(NewDevExt, sizeof(SFILTER_DEVICE_EXTENSION));    NewDevExt->StorageStackDeviceObject = StorageStackDeviceObject;

//  // Get the name of this device  // 得到名字用于调试显示  //  RtlInitEmptyUnicodeString(&NewDevExt->DeviceName,   NewDevExt->DeviceNameBuffer,   sizeof(NewDevExt->DeviceNameBuffer)   );

SfGetObjectName(StorageStackDeviceObject,   &NewDevExt->DeviceName   );

//  // Initialize some useful variables  // 初始化一些有用的变量  //  ExInitializeFastMutex(&NewDevExt->FsCtxTableMutex);

// 文件系统调用RtlInitializeGenericTable初始化存储文件系统特定数据的通用表  // 如当前打开文件的名字查找信息  // 排序顺序，结构，元素内容是调用者定义的  RtlInitializeGenericTable(&NewDevExt->FsCtxTable,   SfGenericCompareRoutine,   SfGenericAllocateRoutine,   SfGenericFreeRoutine,   NULL   );

//  // VERSION NOTE:  //  // On Windows 2000, we cannot simply synchronize back to the dispatch  // routine to do our post-mount processing.  We need to do this work at  // passive level, so we will queue that work to a worker thread from  // the completion routine.  // 对于Windows 2000，我们不能简单同步回分发例程以执行我们的后安装处理。     // 我们需要在passive级执行这个工作，因此我们将从完成例程中入队那个工作到工作线程。  //  // For Windows XP and later, we can safely synchronize back to the dispatch  // routine.  The code below shows both methods.  Admittedly, the code  // would be simplified if you chose to only use one method or the other,  // but you should be able to easily adapt this for your needs.  // 对于Windows XP and later，我们可以安全同步回分发例程。下面代码显示这两种方法。  //

#if WINVER >= 0x0501  if (IS_WINDOWSXP_OR_LATER())  {   KEVENT WaitEvent;

KeInitializeEvent(&WaitEvent, NotificationEvent, FALSE);

IoCopyCurrentIrpStackLocationToNext(Irp);

IoSetCompletionRoutine(Irp,    SfFsControlCompletion,    &WaitEvent,  // context parameter    TRUE,    TRUE,    TRUE    );

Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);

//   // Wait for the operation to complete   // 等待操作完成   //   if (STATUS_PENDING == Status)   {    Status = KeWaitForSingleObject(&WaitEvent,     Executive,     KernelMode,     FALSE,     NULL     );    ASSERT(STATUS_SUCCESS == Status);   }

//   // Verify the IoCompleteRequest was called   // 验证IoCompleteRequest被调用   //   ASSERT(KeReadStateEvent(&WaitEvent) ||    !NT_SUCCESS(Irp->IoStatus.Status));

Status = SfFsControlMountVolumeComplete(    DeviceObject,    Irp,    NewDeviceObject    );  }  else  { #endif   //   // Initialize our completion routine   // 初始化我们的完成例程   //   CompletionContext = ExAllocatePoolWithTag(    NonPagedPool,    sizeof(FSCTRL_COMPLETION_CONTEXT),    SFLT_POOL_TAG    );   if (CompletionContext == NULL)   {    //    // If we cannot allocate our completion context, we will just pass    // through the operation.  If your filter must be present for data    // access to this volume, you should consider failing the operation    // if memory cannot be allocated here.    // 如果我们不能分配我们的完成上下文，我们将仅通过这个操作。    // 如果你的过滤器当对这个卷进行数据存取时必须存在，你应该在内存不能分配时考虑失败这个请求    //

IoSkipCurrentIrpStackLocation(Irp);    Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);   }   else   {    ExInitializeWorkItem(&CompletionContext->WorkItem,     SfFsControlMountVolumeCompleteWorker,     CompletionContext     );

CompletionContext->DeviceObject = DeviceObject;    CompletionContext->Irp = Irp;    CompletionContext->NewDeviceObject = NewDeviceObject;

IoCopyCurrentIrpStackLocationToNext(Irp);

IoSetCompletionRoutine(Irp,     SfFsControlCompletion,     &CompletionContext->WorkItem, // context parameter     TRUE,     TRUE,     TRUE     );

//    // Call the driver    // 调用驱动    //    Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);   } #if WINVER >= 0x0501   } #endif

return Status; }

VOID SfFsControlMountVolumeCompleteWorker(  IN PFSCTRL_COMPLETION_CONTEXT Context  ) /*++

Routine Description:

// 工作线程例程将调用我们的公共例程执行后-卷安装工作  The worker thread routine that will call our common routine to do the  post-MountVolume work.

Arguments:

Context - The context passed to this worker thread.   Return Value:

None.

--*/ {  ASSERT(Context != NULL);

SfFsControlMountVolumeComplete(   Context->DeviceObject,   Context->Irp,   Context->NewDeviceObject   );

ExFreePoolWithTag(Context, SFLT_POOL_TAG); }

NTSTATUS SfFsControlMountVolumeComplete(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PDEVICE_OBJECT NewDeviceObject  ) /*++

Routine Description:

// 这执行后安装工作且必须在PASSIVE_LEVEL执行  This does the post-Mount work and must be done at PASSIVE_LEVEL.

Arguments:

DeviceObject - The device object for this operation,

Irp - The IRP for this operation that we will complete once we are finished   with it.   Return Value:

Returns the status of the mount operation.

--*/ {  PVPB Vpb;  PSFILTER_DEVICE_EXTENSION NewDevExt;  PIO_STACK_LOCATION IrpSp;  PDEVICE_OBJECT AttachedDeviceObject;  NTSTATUS Status;

PAGED_CODE();

NewDevExt = NewDeviceObject->DeviceExtension;  IrpSp = IoGetCurrentIrpStackLocation(Irp);    //  // Get the correct VPB from the real device object saved in our  // device extension.  We do this because the VPB in the IRP stack  // may not be the correct VPB when we get here.  The underlying  // file system may change VPBs if it detects a volume it has  // mounted previously.  // 从我们保存的的设备扩展中的真实设备对象得到正确的VPB  //  Vpb = NewDevExt->StorageStackDeviceObject->Vpb;

//  // Display a message when we detect that the VPB for the given  // device object has changed.  // 当我们探测到给定设备对象的VPB已经改变，显示一个消息。  //  if (Vpb != IrpSp->Parameters.MountVolume.Vpb)  {   SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,        ("SFilter!SfFsControlMountVolume:     VPB in IRP stack changed %p IRPVPB=%p VPB=%p/n",       Vpb->DeviceObject,       IrpSp->Parameters.MountVolume.Vpb,       Vpb));  }

//  // See if the mount was successful.  // 看是否卷安装成功  //  if (NT_SUCCESS(Irp->IoStatus.Status))  {   //   // Acquire lock so we can atomically test if we area already attached   // and if not, then attach.  This prevents a double attach race   // condition.   // 请求锁以使得我们能够自动测试是否我们已经附着或未附着，然后附着。         // 这阻止重复附着的竞争条件

//   ExAcquireFastMutex(&gSfilterAttachLock);

//   // The mount succeeded.  If we are not already attached, attach to the   // device object.  Note: one reason we could already be attached is   // if the underlying file system revived a previous mount.   // 安装成功。如果我们尚未附着，附着到设备对象。注意：我们已经附着的情况是         // 是否下面的文件系统接收到一个前面的安装   //   if (!SfIsAttachedToDevice(Vpb->DeviceObject, &AttachedDeviceObject))   {    //    // Attach to the new mounted volume.  The file system device    // object that was just mounted is pointed to by the VPB.    // 尚未附着，现在附着到新安装的卷。刚安装的文件系统设备对象由VPB指向。    //    Status = SfAttachToMountedDevice(Vpb->DeviceObject, NewDeviceObject);    if (!NT_SUCCESS(Status))    {     //     // The attachment failed, cleanup.  Since we are in the     // post-mount phase, we can not fail this operation.     // We simply won't be attached.  The only reason this should     // ever happen at this point is if somebody already started     // dismounting the volume therefore not attaching should     // not be a problem.     // 附着失败，清除。因为我们处于后-安装步骤，我们不能失败这个操作。     // 我们仅简单地不附着。唯一发生这个的原因是有人已经开始卸载这个卷，因此不附着不应该是问题。     //     SfCleanupMountedDevice(NewDeviceObject);     IoDeleteDevice(NewDeviceObject);    }

ASSERT(NULL == AttachedDeviceObject);   }   else   {    //    // We were already attached, handle it    // 我们已经附着，处理它。    //    SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,         ("SFilter!SfFsControlMountVolume    Mount volume failure for %p /"%wZ/", already attached/n",        ((PSFILTER_DEVICE_EXTENSION)AttachedDeviceObject->DeviceExtension)->AttachedToDeviceObject,        &NewDevExt->DeviceName));

//    // Cleanup and delete the device object we created    // 清除且删除我们创建的设备对象    //    SfCleanupMountedDevice(NewDeviceObject);    IoDeleteDevice(NewDeviceObject);

//    // Dereference the returned attached device object    // 解除对返回的附着设备对象的引用    //    ObDereferenceObject(AttachedDeviceObject);   }

//   // Release the lock   // 释放锁   //   ExReleaseFastMutex(&gSfilterAttachLock);  }  else  {   //   // The mount request failed, handle it.   // 安装请求失败，处理它。   //   SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,        ("SFilter!SfFsControlMountVolume:     Mount volume failure for %p /"%wZ/", Status=%08x/n",       DeviceObject,       &NewDevExt->DeviceName,       Irp->IoStatus.Status));

//   // Cleanup and delete the device object we created   // 清除且删除我们创建的设备对象   //   SfCleanupMountedDevice(NewDeviceObject);   IoDeleteDevice(NewDeviceObject);  }

//  // Complete the request.   // NOTE:  We must save the Status before completing because after  //  completing the IRP we can not longer access it (it might be  //  freed).  // 完成请求  // 注意：我们必须在完成前保存状态因为完成IRP后我们不能再存取它（IRP）了，因为它可能被释放了  //  Status = Irp->IoStatus.Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);

return Status; }

NTSTATUS SfFsControlLoadFileSystem(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

This routine is invoked whenever an I/O Request Packet (IRP) w/a major  function code of IRP_MJ_FILE_SYSTEM_CONTROL is encountered.  For most  IRPs of this type, the packet is simply passed through.  However, for  some requests, special processing is required.

Arguments:

DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

Return Value:

The function value is the status of the operation.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt = DeviceObject->DeviceExtension;  NTSTATUS Status;  PFSCTRL_COMPLETION_CONTEXT CompletionContext;

PAGED_CODE();

//  // This is a "load file system" request being sent to a file system  // recognizer device object.  This IRP_MN code is only sent to  // file system recognizers.  // 这是被发送到文件系统识别器设备对象的“装入文件系统”，这个  // IRP_MN代码仅发送到文件系统识别器。  //  // NOTE:  Since we no longer are attaching to the standard Microsoft file  //  system recognizers we will normally never execute this code.  //  However, there might be 3rd party file systems which have their  //  own recognizer which may still trigger this IRP.  // 因为我们不再附着到标准微软文件系统识别器，我们正常情况下不执行这个代码。  // 但是，可能有他们自己的识别器第三方文件系统可能触发这个IRP  //

//  // VERSION NOTE:  //  // On Windows 2000, we cannot simply synchronize back to the dispatch  // routine to do our post-load filesystem processing.  We need to do  // this work at passive level, so we will queue that work to a worker  // thread from the completion routine.  //  // For Windows XP and later, we can safely synchronize back to the dispatch  // routine.  The code below shows both methods.  Admittedly, the code  // would be simplified if you chose to only use one method or the other,  // but you should be able to easily adapt this for your needs.  //

#if WINVER >= 0x0501  if (IS_WINDOWSXP_OR_LATER())  {   KEVENT WaitEvent;     KeInitializeEvent(&WaitEvent, NotificationEvent, FALSE);

IoCopyCurrentIrpStackLocationToNext(Irp);     IoSetCompletionRoutine(    Irp,    SfFsControlCompletion,    &WaitEvent,  // context parameter    TRUE,    TRUE,    TRUE    );

//   // Detach from the recognizer's device object   // 从文件系统识别器设备对象上断开附着   //   IoDetachDevice(DevExt->AttachedToDeviceObject);

//  调用驱动         //  Call the driver   Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);

//   // Wait for the operation to complete   //   if (STATUS_PENDING == Status)   {    Status = KeWaitForSingleObject(     &WaitEvent,     Executive,     KernelMode,     FALSE,     NULL     );    ASSERT(STATUS_SUCCESS == Status);   }

if (!NT_SUCCESS(Status))   {    //    // The load was not successful.  Simply reattach to the recognizer    // driver in case it ever figures out how to get the driver loaded    // on a subsequent call.  There is not a lot we can do if this    // reattach fails.    //       SfAttachDeviceToDeviceStack(DeviceObject,     DevExt->AttachedToDeviceObject,     &DevExt->AttachedToDeviceObject);

ASSERT(DevExt->AttachedToDeviceObject != NULL);   }

//   // Verify the IoCompleteRequest was called   //   ASSERT(KeReadStateEvent(&WaitEvent) ||    !NT_SUCCESS(Irp->IoStatus.Status));

Status = SfFsControlLoadFileSystemComplete(DeviceObject, Irp);  }  else  { #endif   //   // Set a completion routine so we can delete the device object when   // the load is complete.   // 设置完成例程，因此我们可以当装入完成时删除设备对象   //   CompletionContext = ExAllocatePoolWithTag(    NonPagedPool,    sizeof(FSCTRL_COMPLETION_CONTEXT),    SFLT_POOL_TAG    );   if (CompletionContext == NULL)   {    //    // If we cannot allocate our completion context, we will just pass    // through the operation.  If your filter must be present for data    // access to this volume, you should consider failing the operation    // if memory cannot be allocated here.    //

IoSkipCurrentIrpStackLocation(Irp);    Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);   }   else   {    ExInitializeWorkItem(&CompletionContext->WorkItem,     SfFsControlLoadFileSystemCompleteWorker,     CompletionContext     );    CompletionContext->DeviceObject = DeviceObject;    CompletionContext->Irp = Irp;    CompletionContext->NewDeviceObject = NULL;         IoCopyCurrentIrpStackLocationToNext(Irp);

IoSetCompletionRoutine(     Irp,     SfFsControlCompletion,     CompletionContext,     TRUE,     TRUE,     TRUE);

//    // Detach from the file system recognizer device object.    // 从文件系统识别器设备对象上断开    //    IoDetachDevice(DevExt->AttachedToDeviceObject);

//    // Call the driver    // 调用驱动    //    Status = IoCallDriver(DevExt->AttachedToDeviceObject, Irp);   } #if WINVER >= 0x0501   } #endif    return Status; }

VOID SfFsControlLoadFileSystemCompleteWorker(  IN PFSCTRL_COMPLETION_CONTEXT Context  ) /*++

Routine Description:

// 工作线程例程将调用我们的公共例程执行后LoadFileSystem工作  The worker thread routine that will call our common routine to do the  post-LoadFileSystem work.

Arguments:

Context - The context passed to this worker thread.   Return Value:

None.

--*/ {  ASSERT(NULL != Context);

SfFsControlLoadFileSystemComplete(Context->DeviceObject, Context->Irp);  ExFreePoolWithTag(Context, SFLT_POOL_TAG); }

NTSTATUS SfFsControlLoadFileSystemComplete(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) /*++

Routine Description:

// 执行后LoadFileSystem装入文件系统工作且必须在PASSIVE_LEVEL执行  This does the post-LoadFileSystem work and must be done as PASSIVE_LEVEL.

Arguments:

DeviceObject - The device object for this operation,

Irp - The IRP for this operation that we will complete once we are finished   with it.   Return Value:

Returns the status of the load file system operation.

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt;  NTSTATUS Status;

PAGED_CODE();

DevExt = DeviceObject->DeviceExtension;    //  // Display the name if requested  //  SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,   ("SFilter!SfFsControlLoadFileSystem:   Detaching from recognizer  %p /"%wZ/", Status=%08x/n",   DeviceObject,   &DevExt->DeviceName,   Irp->IoStatus.Status)   );

//  // Check Status of the operation  //  if (!NT_SUCCESS(Irp->IoStatus.Status) &&   (Irp->IoStatus.Status != STATUS_IMAGE_ALREADY_LOADED))  {   //   // The load was not successful.  Simply reattach to the recognizer   // driver in case it ever figures out how to get the driver loaded   // on a subsequent call.  There is not a lot we can do if this   // reattach fails.   // 装载文件系统未成功。简单地重新附着到识别器驱动以防它指出如何得到驱动   // 在后续调用中被装载   //

SfAttachDeviceToDeviceStack(DeviceObject,    DevExt->AttachedToDeviceObject,    &DevExt->AttachedToDeviceObject);

ASSERT(DevExt->AttachedToDeviceObject != NULL);

}  else  {   //   // The load was successful, so cleanup this device and delete the   // Device object   // 装载成功，因此清除这个设备且删除设备对象   //   SfCleanupMountedDevice(DeviceObject);   IoDeleteDevice(DeviceObject);  }

//  // Continue processing the operation  // 继续处理操作  //  Status = Irp->IoStatus.Status;  IoCompleteRequest(Irp, IO_NO_INCREMENT);

return Status; }

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //     FastIO Handling routines // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

BOOLEAN SfFastIoCheckIfPossible(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  IN BOOLEAN CheckForReadOperation,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

// 快速I/O直通例程用于检测是否对于这个文件快速I/O可用  This routine is the fast I/O "pass through" routine for checking to see  whether fast I/O is possible for this file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.  // 这个例程简单调用文件系统的对应例程，或者如果文件系统没有实现这个函数返回FALSE

Arguments:

FileObject - Pointer to the file object to be operated on. // 要操作的文件对象

FileOffset - Byte offset in the file for the operation.  // 操作的文件字节偏移

Length - Length of the operation to be performed.   // 将执行的操作长度

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired    // 指示如果相应的锁等等不能被请求到是否调用者将想等待

LockKey - Provides the caller's key for file locks.   // 提供用于文件锁的调用者的键

CheckForReadOperation - Indicates whether the caller is checking for a   read (TRUE) or a write operation.      // 指示是否调用者正检查一个读(TRUE)或者一个写操作

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   // 对于这个类型的快速I/O传递逻辑   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoCheckIfPossible))   {    return (FastIoDispatch->FastIoCheckIfPossible)(     FileObject,     FileOffset,     Length,     Wait,     LockKey,     CheckForReadOperation,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoRead(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  OUT PVOID Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for reading from a  file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be read.

FileOffset - Byte offset in the file of the read.

Length - Length of the read operation to be performed.

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired

LockKey - Provides the caller's key for file locks.

Buffer - Pointer to the caller's buffer to receive the data read.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoRead))   {    return (FastIoDispatch->FastIoRead)(     FileObject,     FileOffset,     Length,     Wait,     LockKey,     Buffer,     IoStatus,     NextDeviceObject     );   }  }  return FALSE; }

BOOLEAN SfFastIoWrite(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN BOOLEAN Wait,  IN ULONG LockKey,  IN PVOID Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for writing to a  file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be written.

FileOffset - Byte offset in the file of the write operation.

Length - Length of the write operation to be performed.

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired

LockKey - Provides the caller's key for file locks.

Buffer - Pointer to the caller's buffer that contains the data to be   written.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();    if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;

if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoWrite))   {    return (FastIoDispatch->FastIoWrite)(     FileObject,     FileOffset,     Length,     Wait,     LockKey,     Buffer,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoQueryBasicInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_BASIC_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for querying basic  information about the file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be queried.

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired

Buffer - Pointer to the caller's buffer to receive the information about   the file.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoQueryBasicInfo))   {    return (FastIoDispatch->FastIoQueryBasicInfo)(     FileObject,     Wait,     Buffer,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoQueryStandardInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_STANDARD_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for querying standard  information about the file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be queried.

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired

Buffer - Pointer to the caller's buffer to receive the information about   the file.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoQueryStandardInfo))   {    return (FastIoDispatch->FastIoQueryStandardInfo)(     FileObject,     Wait,     Buffer,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoLock(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PLARGE_INTEGER Length,  PEPROCESS ProcessId,  ULONG Key,  BOOLEAN FailImmediately,  BOOLEAN ExclusiveLock,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for locking a byte  range within a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be locked.

FileOffset - Starting byte offset from the base of the file to be locked.

Length - Length of the byte range to be locked.

ProcessId - ID of the process requesting the file lock. // 请求文件锁的进程ID

Key - Lock key to associate with the file lock.

FailImmediately - Indicates whether or not the lock request is to fail   if it cannot be immediately be granted.  // 指示是否当锁不能被立即授予的情况下是否失败锁请求

ExclusiveLock - Indicates whether the lock to be taken is exclusive (TRUE)   or shared.  // 指示是否锁是排他性(TRUE)或者是共享的

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoLock))   {    return (FastIoDispatch->FastIoLock)(     FileObject,     FileOffset,     Length,     ProcessId,     Key,     FailImmediately,     ExclusiveLock,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoUnlockSingle(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PLARGE_INTEGER Length,  PEPROCESS ProcessId,  ULONG Key,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for unlocking a byte  range within a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be unlocked.

FileOffset - Starting byte offset from the base of the file to be   unlocked.

Length - Length of the byte range to be unlocked.

ProcessId - ID of the process requesting the unlock operation.

Key - Lock key associated with the file lock.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoUnlockSingle))   {    return (FastIoDispatch->FastIoUnlockSingle)(     FileObject,     FileOffset,     Length,     ProcessId,     Key,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoUnlockAll(  IN PFILE_OBJECT FileObject,  PEPROCESS ProcessId,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for unlocking all  locks within a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be unlocked.

ProcessId - ID of the process requesting the unlock operation.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   if (NextDeviceObject)   {    FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;    if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoUnlockAll))    {     return (FastIoDispatch->FastIoUnlockAll)(      FileObject,      ProcessId,      IoStatus,      NextDeviceObject      );    }   }  }

return FALSE; }

BOOLEAN SfFastIoUnlockAllByKey(  IN PFILE_OBJECT FileObject,  PVOID ProcessId,  ULONG Key,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for unlocking all  locks within a file based on a specified key.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be unlocked.

ProcessId - ID of the process requesting the unlock operation.

Key - Lock key associated with the locks on the file to be released.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoUnlockAllByKey))   {    return (FastIoDispatch->FastIoUnlockAllByKey)(     FileObject,     ProcessId,     Key,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoDeviceControl(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  IN PVOID InputBuffer OPTIONAL,  IN ULONG InputBufferLength,  OUT PVOID OutputBuffer OPTIONAL,  IN ULONG OutputBufferLength,  IN ULONG IoControlCode,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for device I/O control  operations on a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object representing the device to be   serviced.

Wait - Indicates whether or not the caller is willing to wait if the   appropriate locks, etc. cannot be acquired

InputBuffer - Optional pointer to a buffer to be passed into the driver.

InputBufferLength - Length of the optional InputBuffer, if one was   specified.

OutputBuffer - Optional pointer to a buffer to receive data from the   driver.

OutputBufferLength - Length of the optional OutputBuffer, if one was   specified.

IoControlCode - I/O control code indicating the operation to be performed   on the device.

IoStatus - Pointer to a variable to receive the I/O status of the   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoDeviceControl))   {    return (FastIoDispatch->FastIoDeviceControl)(     FileObject,     Wait,     InputBuffer,     InputBufferLength,     OutputBuffer,     OutputBufferLength,     IoControlCode,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

VOID SfFastIoDetachDevice(  IN PDEVICE_OBJECT SourceDevice,  IN PDEVICE_OBJECT TargetDevice  ) /*++

Routine Description:

This routine is invoked on the fast path to detach from a device that  is being deleted.  This occurs when this driver has attached to a file  system volume device object, and then, for some reason, the file system  decides to delete that device (it is being dismounted, it was dismounted  at some point in the past and its last reference has just gone away, etc.)  这个例程在快速路径上的断开将被删除的设备。这发生在当这个设备已经附着到一个文件系统卷设备对象，  且然后，由于某种原因，文件系统决定删除那个设备  （他被卸载，它被在过去的某个点卸载且他的最后引用计数已经消失等等）

Arguments:

SourceDevice - Pointer to my device object, which is attached   to the file system's volume device object.

TargetDevice - Pointer to the file system's volume device object.

Return Value:

None

--*/ {  PSFILTER_DEVICE_EXTENSION DevExt;

PAGED_CODE();

ASSERT(IS_MY_DEVICE_OBJECT(SourceDevice));

DevExt = SourceDevice->DeviceExtension;

//  // Display name information  // 显示名字信息  //  SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,       ("SFilter!SfFastIoDetachDevice:    Detaching from volume   %p /"%wZ/"/n",      TargetDevice,      &DevExt->DeviceName));

//  // Detach from the file system's volume device object.  // 从文件系统的卷设备对象上断开  //  SfCleanupMountedDevice(SourceDevice);  IoDetachDevice(TargetDevice);  IoDeleteDevice(SourceDevice); }

BOOLEAN SfFastIoQueryNetworkOpenInfo(  IN PFILE_OBJECT FileObject,  IN BOOLEAN Wait,  OUT PFILE_NETWORK_OPEN_INFORMATION Buffer,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for querying network  information about a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object to be queried.

Wait - Indicates whether or not the caller can handle the file system   having to wait and tie up the current thread.

Buffer - Pointer to a buffer to receive the network information about the   file.

IoStatus - Pointer to a variable to receive the final status of the query   operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoQueryNetworkOpenInfo))   {    return (FastIoDispatch->FastIoQueryNetworkOpenInfo)(     FileObject,     Wait,     Buffer,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoMdlRead(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for reading a file  using MDLs as buffers.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object that is to be read.

FileOffset - Supplies the offset into the file to begin the read operation.

Length - Specifies the number of bytes to be read from the file.

LockKey - The key to be used in byte range lock checks.

MdlChain - A pointer to a variable to be filled in w/a pointer to the MDL   chain built to describe the data read.  // 将被填入的变量的指针在用于描述数据读的MDL链的w/a指针

IoStatus - Variable to receive the final status of the read operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, MdlRead))   {    return (FastIoDispatch->MdlRead)(     FileObject,     FileOffset,     Length,     LockKey,     MdlChain,     IoStatus,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoMdlReadComplete(  IN PFILE_OBJECT FileObject,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for completing an  MDL read operation.

This function simply invokes the file system's corresponding routine, if  it has one.  It should be the case that this routine is invoked only if  the MdlRead function is supported by the underlying file system, and  therefore this function will also be supported, but this is not assumed  by this driver.

Arguments:

FileObject - Pointer to the file object to complete the MDL read upon.

MdlChain - Pointer to the MDL chain used to perform the read operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE, depending on whether or not it is  possible to invoke this function on the fast I/O path.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, MdlReadComplete))   {    return (FastIoDispatch->MdlReadComplete)(     FileObject,     MdlChain,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoPrepareMdlWrite(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for preparing for an  MDL write operation.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object that will be written.

FileOffset - Supplies the offset into the file to begin the write operation.

Length - Specifies the number of bytes to be write to the file.

LockKey - The key to be used in byte range lock checks.

MdlChain - A pointer to a variable to be filled in w/a pointer to the MDL   chain built to describe the data written.

IoStatus - Variable to receive the final status of the write operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT nextDeviceObject;  PFAST_IO_DISPATCH fastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   nextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(nextDeviceObject);

fastIoDispatch = nextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(fastIoDispatch, PrepareMdlWrite))   {    return (fastIoDispatch->PrepareMdlWrite)(     FileObject,     FileOffset,     Length,     LockKey,     MdlChain,     IoStatus,     nextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoMdlWriteComplete(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for completing an  MDL write operation.

This function simply invokes the file system's corresponding routine, if  it has one.  It should be the case that this routine is invoked only if  the PrepareMdlWrite function is supported by the underlying file system,  and therefore this function will also be supported, but this is not  assumed by this driver.

Arguments:

FileObject - Pointer to the file object to complete the MDL write upon.

FileOffset - Supplies the file offset at which the write took place.

MdlChain - Pointer to the MDL chain used to perform the write operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE, depending on whether or not it is  possible to invoke this function on the fast I/O path.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, MdlWriteComplete))   {    return (FastIoDispatch->MdlWriteComplete)(     FileObject,     FileOffset,     MdlChain,     NextDeviceObject     );   }  }

return FALSE; }

/*********************************************************************************   UNIMPLEMENTED FAST IO ROUTINES // 未实现的快速IO例程     The following four Fast IO routines are for compression on the wire   which is not yet implemented in NT.  // 下面四个快速IO例程用于在NT中尚未实现的在线压缩     NOTE:  It is highly recommended that you include these routines (which     do a pass-through call) so your filter will not need to be     modified in the future when this functionality is implemented in     the OS.     FastIoReadCompressed, FastIoWriteCompressed,   FastIoMdlReadCompleteCompressed, FastIoMdlWriteCompleteCompressed **********************************************************************************/

BOOLEAN SfFastIoReadCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  OUT PVOID Buffer,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  OUT struct _COMPRESSED_DATA_INFO *CompressedDataInfo,  IN ULONG CompressedDataInfoLength,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for reading compressed  data from a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object that will be read.

FileOffset - Supplies the offset into the file to begin the read operation.

Length - Specifies the number of bytes to be read from the file.

LockKey - The key to be used in byte range lock checks.

Buffer - Pointer to a buffer to receive the compressed data read.

MdlChain - A pointer to a variable to be filled in w/a pointer to the MDL   chain built to describe the data read.

IoStatus - Variable to receive the final status of the read operation.

CompressedDataInfo - A buffer to receive the description of the compressed   data.  // 接收已经压缩数据的描述的缓冲

CompressedDataInfoLength - Specifies the size of the buffer described by   the CompressedDataInfo parameter. // 指定由CompressedDataInfo参数描述的缓冲尺寸

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/ {  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoReadCompressed))   {    return (FastIoDispatch->FastIoReadCompressed)(     FileObject,     FileOffset,     Length,     LockKey,     Buffer,     MdlChain,     IoStatus,     CompressedDataInfo,     CompressedDataInfoLength,     NextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoWriteCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN ULONG Length,  IN ULONG LockKey,  IN PVOID Buffer,  OUT PMDL *MdlChain,  OUT PIO_STATUS_BLOCK IoStatus,  IN struct _COMPRESSED_DATA_INFO *CompressedDataInfo,  IN ULONG CompressedDataInfoLength,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for writing compressed  data to a file.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

FileObject - Pointer to the file object that will be written.

FileOffset - Supplies the offset into the file to begin the write operation.

Length - Specifies the number of bytes to be write to the file.

LockKey - The key to be used in byte range lock checks.

Buffer - Pointer to the buffer containing the data to be written.

MdlChain - A pointer to a variable to be filled in w/a pointer to the MDL   chain built to describe the data written.

IoStatus - Variable to receive the final status of the write operation.

CompressedDataInfo - A buffer to containing the description of the   compressed data.

CompressedDataInfoLength - Specifies the size of the buffer described by   the CompressedDataInfo parameter.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoWriteCompressed))   {    return (FastIoDispatch->FastIoWriteCompressed)(     FileObject,     FileOffset,     Length,     LockKey,     Buffer,     MdlChain,     IoStatus,     CompressedDataInfo,     CompressedDataInfoLength,     NextDeviceObject     );   }  }  return FALSE; }

BOOLEAN SfFastIoMdlReadCompleteCompressed(  IN PFILE_OBJECT FileObject,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for completing an  MDL read compressed operation.

This function simply invokes the file system's corresponding routine, if  it has one.  It should be the case that this routine is invoked only if  the read compressed function is supported by the underlying file system,  and therefore this function will also be supported, but this is not assumed  by this driver.

Arguments:

FileObject - Pointer to the file object to complete the compressed read   upon.

MdlChain - Pointer to the MDL chain used to perform the read operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE, depending on whether or not it is  possible to invoke this function on the fast I/O path.

--*/ {  PDEVICE_OBJECT nextDeviceObject;  PFAST_IO_DISPATCH fastIoDispatch;

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   nextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(nextDeviceObject);

fastIoDispatch = nextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(fastIoDispatch, MdlReadCompleteCompressed))   {    return (fastIoDispatch->MdlReadCompleteCompressed)(     FileObject,     MdlChain,     nextDeviceObject     );   }  }  return FALSE; }

BOOLEAN SfFastIoMdlWriteCompleteCompressed(  IN PFILE_OBJECT FileObject,  IN PLARGE_INTEGER FileOffset,  IN PMDL MdlChain,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for completing a  write compressed operation.

This function simply invokes the file system's corresponding routine, if  it has one.  It should be the case that this routine is invoked only if  the write compressed function is supported by the underlying file system,  and therefore this function will also be supported, but this is not assumed  by this driver.

Arguments:

FileObject - Pointer to the file object to complete the compressed write   upon.

FileOffset - Supplies the file offset at which the file write operation   began.

MdlChain - Pointer to the MDL chain used to perform the write operation.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE, depending on whether or not it is  possible to invoke this function on the fast I/O path.

--*/ {  PDEVICE_OBJECT nextDeviceObject;  PFAST_IO_DISPATCH fastIoDispatch;

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   nextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(nextDeviceObject);

fastIoDispatch = nextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(fastIoDispatch, MdlWriteCompleteCompressed))   {    return (fastIoDispatch->MdlWriteCompleteCompressed)(     FileObject,     FileOffset,     MdlChain,     nextDeviceObject     );   }  }

return FALSE; }

BOOLEAN SfFastIoQueryOpen(  IN PIRP Irp,  OUT PFILE_NETWORK_OPEN_INFORMATION NetworkInformation,  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This routine is the fast I/O "pass through" routine for opening a file  and returning network information for it.

This function simply invokes the file system's corresponding routine, or  returns FALSE if the file system does not implement the function.

Arguments:

Irp - Pointer to a create IRP that represents this open operation.  It is   to be used by the file system for common open/create code, but not   actually completed.

NetworkInformation - A buffer to receive the information required by the   network about the file being opened.

DeviceObject - Pointer to this driver's device object, the device on   which the operation is to occur.

Return Value:

The function value is TRUE or FALSE based on whether or not fast I/O  is possible for this file.

--*/

{  PDEVICE_OBJECT NextDeviceObject;  PFAST_IO_DISPATCH FastIoDispatch;  BOOLEAN Result;

PAGED_CODE();

if (DeviceObject->DeviceExtension)  {   ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

//   // Pass through logic for this type of Fast I/O   //   NextDeviceObject = ((PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension)->AttachedToDeviceObject;   ASSERT(NextDeviceObject);

FastIoDispatch = NextDeviceObject->DriverObject->FastIoDispatch;   if (VALID_FAST_IO_DISPATCH_HANDLER(FastIoDispatch, FastIoQueryOpen))   {    PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);

//    // Before calling the next filter, we must make sure their device    // object is in the current stack entry for the given IRP    //    IrpSp->DeviceObject = NextDeviceObject;

Result = (FastIoDispatch->FastIoQueryOpen)(     Irp,     NetworkInformation,     NextDeviceObject     );

//    // Always restore the IRP back to our device object    //    IrpSp->DeviceObject = DeviceObject;    return Result;   }  }

return FALSE; }

#if WINVER >= 0x0501 /* See comment in DriverEntry */ // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //    FSFilter callback handling routines // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

NTSTATUS SfPreFsFilterPassThrough(  IN PFS_FILTER_CALLBACK_DATA Data,  OUT PVOID *CompletionContext  ) /*++

Routine Description:

This routine is the FS Filter pre-operation "pass through" routine.

Arguments:

Data - The FS_FILTER_CALLBACK_DATA structure containing the information   about this operation.    CompletionContext - A context set by this operation that will be passed   to the corresponding SfPostFsFilterOperation call.   Return Value:

Returns STATUS_SUCCESS if the operation can continue or an appropriate  error code if the operation should fail.

--*/ {  UNREFERENCED_PARAMETER(Data);  UNREFERENCED_PARAMETER(CompletionContext);

ASSERT(IS_MY_DEVICE_OBJECT(Data->DeviceObject));

return STATUS_SUCCESS; }

VOID SfPostFsFilterPassThrough(  IN PFS_FILTER_CALLBACK_DATA Data,  IN NTSTATUS OperationStatus,  IN PVOID CompletionContext  ) /*++

Routine Description:

This routine is the FS Filter post-operation "pass through" routine.

Arguments:

Data - The FS_FILTER_CALLBACK_DATA structure containing the information   about this operation.    OperationStatus - The status of this operation.     CompletionContext - A context that was set in the pre-operation   callback by this driver.   Return Value:

None.   --*/ {  UNREFERENCED_PARAMETER(Data);  UNREFERENCED_PARAMETER(OperationStatus);  UNREFERENCED_PARAMETER(CompletionContext);

ASSERT(IS_MY_DEVICE_OBJECT(Data->DeviceObject)); } #endif

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // / // //    Support routines // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

NTSTATUS SfAttachDeviceToDeviceStack(  IN PDEVICE_OBJECT SourceDevice,  IN PDEVICE_OBJECT TargetDevice,  IN OUT PDEVICE_OBJECT *AttachedToDeviceObject  ) /*++

Routine Description:

This routine attaches the SourceDevice to the TargetDevice's stack and  returns the device object SourceDevice was directly attached to in  AttachedToDeviceObject.  Note that the SourceDevice does not necessarily  get attached directly to TargetDevice.  The SourceDevice will get attached  to the top of the stack of which TargetDevice is a member.

VERSION NOTE:

In Windows XP, a new API was introduced to close a rare timing window that  can cause IOs to start being sent to a device before its  AttachedToDeviceObject is set in its device extension.  This is possible  if a filter is attaching to a device stack while the system is actively  processing IOs.  The new API closes this timing window by setting the  device extension field that holds the AttachedToDeviceObject while holding  the IO Manager's lock that protects the device stack.

A sufficient work around for earlier versions of the OS is to set the  AttachedToDeviceObject to the device object that the SourceDevice is most  likely to attach to.  While it is possible that another filter will attach  in between the SourceDevice and TargetDevice, this will prevent the  system from bug checking if the SourceDevice receives IOs before the  AttachedToDeviceObject is correctly set.

For a driver built in the Windows 2000 build environment, we will always  use the work-around code to attach.  For a driver that is built in the  Windows XP or later build environments (therefore you are building a  multiversion driver), we will determine which method of attachment to use  based on which APIs are available.

Arguments:

SourceDevice - The device object to be attached to the stack.

TargetDevice - The device that we currently think is the top of the stack   to which SourceDevice should be attached.

AttachedToDeviceObject - This is set to the device object to which   SourceDevice is attached if the attach is successful.   Return Value:

Return STATUS_SUCCESS if the device is successfully attached.  If  TargetDevice represents a stack to which devices can no longer be attached,  STATUS_NO_SUCH_DEVICE is returned.

--*/ {

PAGED_CODE();

#if WINVER >= 0x0501

if (IS_WINDOWSXP_OR_LATER()) {

ASSERT(NULL != gSfDynamicFunctions.AttachDeviceToDeviceStackSafe);   return (gSfDynamicFunctions.AttachDeviceToDeviceStackSafe)(SourceDevice,                  TargetDevice,                  AttachedToDeviceObject);

} else {

ASSERT(NULL == gSfDynamicFunctions.AttachDeviceToDeviceStackSafe); #endif

*AttachedToDeviceObject = TargetDevice;   *AttachedToDeviceObject = IoAttachDeviceToDeviceStack(SourceDevice,                 TargetDevice);

if (*AttachedToDeviceObject == NULL) {

return STATUS_NO_SUCH_DEVICE;   }

return STATUS_SUCCESS;

#if WINVER >= 0x0501  } #endif }   NTSTATUS SfAttachToFileSystemDevice(  IN PDEVICE_OBJECT DeviceObject,  IN PUNICODE_STRING DeviceName  ) /*++

Routine Description:

This will attach to the given file system device object.  We attach to  these devices so we will know when new volumes are mounted.

Arguments:

DeviceObject - The device to attach to

Name - An already initialized unicode string used to retrieve names.    This is passed in to reduce the number of strings buffers on    the stack.

Return Value:

Status of the operation

--*/ {  PDEVICE_OBJECT NewDeviceObject;  PSFILTER_DEVICE_EXTENSION DevExt;  UNICODE_STRING FsRecName;  NTSTATUS Status;  UNICODE_STRING FsName;  WCHAR TempNameBuffer[MAX_DEVNAME_LENGTH];

PAGED_CODE();

//  // See if this is a file system type we care about.  If not, return.  //  if (!IS_DESIRED_DEVICE_TYPE(DeviceObject->DeviceType))   return STATUS_SUCCESS;

//  // always init NAME buffer  //  RtlInitEmptyUnicodeString(&FsName,   TempNameBuffer,   sizeof(TempNameBuffer)   );

//  // See if we should attach to the standard file system recognizer device  // or not  //  if (!FlagOn(SfDebug,SFDEBUG_ATTACH_TO_FSRECOGNIZER))  {   //   // See if this is one of the standard Microsoft file system recognizer   // devices (see if this device is in the FS_REC driver).  If so skip   // it.  We no longer attach to file system recognizer devices, we   // simply wait for the real file system driver to load.   //   RtlInitUnicodeString(&FsRecName, L"//FileSystem//Fs_Rec");

SfGetObjectName(DeviceObject->DriverObject, &FsName);

if (RtlCompareUnicodeString(&FsName, &FsRecName, TRUE) == 0)    return STATUS_SUCCESS;  }

//  // We want to attach to this file system.  Create a new device object we  // can attach with.  //  Status = IoCreateDevice(gSFilterDriverObject,    sizeof(SFILTER_DEVICE_EXTENSION),    NULL,    DeviceObject->DeviceType,    0,    FALSE,    &NewDeviceObject    );  if (!NT_SUCCESS(Status))   return Status;

//  // Propagate flags from Device Object we are trying to attach to.  // Note that we do this before the actual attachment to make sure  // the flags are properly set once we are attached (since an IRP  // can come in immediately after attachment but before the flags would  // be set).  //

if (FlagOn(DeviceObject->Flags, DO_BUFFERED_IO)) {

SetFlag(NewDeviceObject->Flags, DO_BUFFERED_IO);  }

if (FlagOn(DeviceObject->Flags, DO_DIRECT_IO)) {

SetFlag(NewDeviceObject->Flags, DO_DIRECT_IO);  }

if (FlagOn(DeviceObject->Characteristics, FILE_DEVICE_SECURE_OPEN)) {

SetFlag(NewDeviceObject->Characteristics, FILE_DEVICE_SECURE_OPEN);  }

//  // Do the attachment  //

DevExt = NewDeviceObject->DeviceExtension;

RtlZeroMemory(DevExt, sizeof(SFILTER_DEVICE_EXTENSION));

Status = SfAttachDeviceToDeviceStack(NewDeviceObject,             DeviceObject,             &DevExt->AttachedToDeviceObject);

if (!NT_SUCCESS(Status)) {

goto ErrorCleanupDevice;  }

//  // Set the name  //

RtlInitEmptyUnicodeString(&DevExt->DeviceName,         DevExt->DeviceNameBuffer,         sizeof(DevExt->DeviceNameBuffer));

RtlCopyUnicodeString(&DevExt->DeviceName, DeviceName);  // Save Name

//  // Mark we are done initializing  //

ClearFlag(NewDeviceObject->Flags, DO_DEVICE_INITIALIZING);

//  // Display who we have attached to  //

SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,       ("SFilter!SfAttachToFileSystemDevice:    Attaching to file system %p /"%wZ/" (%s)/n",      DeviceObject,      &DevExt->DeviceName,      GET_DEVICE_TYPE_NAME(NewDeviceObject->DeviceType)));

//  // VERSION NOTE:  //  // In Windows XP, the IO Manager provided APIs to safely enumerate all the  // device objects for a given driver.  This allows filters to attach to  // all mounted volumes for a given file system at some time after the  // volume has been mounted.  There is no support for this functionality  // in Windows 2000.  //  // MULTIVERSION NOTE:  //  // If built for Windows XP or later, this driver is built to run on  // multiple versions.  When this is the case, we will test  // for the presence of the new IO Manager routines that allow for volume  // enumeration.  If they are not present, we will not enumerate the volumes  // when we attach to a new file system.  //   #if WINVER >= 0x0501

if (IS_WINDOWSXP_OR_LATER())  {   ASSERT(NULL != gSfDynamicFunctions.EnumerateDeviceObjectList &&    NULL != gSfDynamicFunctions.GetDiskDeviceObject &&    NULL != gSfDynamicFunctions.GetDeviceAttachmentBaseRef &&    NULL != gSfDynamicFunctions.GetLowerDeviceObject    );

//   // Enumerate all the mounted devices that currently   // exist for this file system and attach to them.   //   Status = SfEnumerateFileSystemVolumes(DeviceObject, &FsName);   if (!NT_SUCCESS(Status))   {    IoDetachDevice(DevExt->AttachedToDeviceObject);    goto ErrorCleanupDevice;   }  }   #endif

return STATUS_SUCCESS;

// // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /  //    Cleanup error handling  // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // // /

ErrorCleanupDevice:  SfCleanupMountedDevice(NewDeviceObject);  IoDeleteDevice(NewDeviceObject);

return Status; }

VOID SfDetachFromFileSystemDevice(  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

Given a base file system device object, this will scan up the attachment  chain looking for our attached device object.  If found it will detach  us from the chain.

Arguments:

DeviceObject - The file system device to detach from.

Return Value:

--*/ {  PDEVICE_OBJECT ourAttachedDevice;  PSFILTER_DEVICE_EXTENSION devExt;

PAGED_CODE();

//  // Skip the base file system device object (since it can't be us)  //

ourAttachedDevice = DeviceObject->AttachedDevice;

while (NULL != ourAttachedDevice) {

if (IS_MY_DEVICE_OBJECT(ourAttachedDevice)) {

devExt = ourAttachedDevice->DeviceExtension;

//    // Display who we detached from    //

SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,         ("SFilter!SfDetachFromFileSystemDevice:  Detaching from file system %p /"%wZ/" (%s)/n",        devExt->AttachedToDeviceObject,        &devExt->DeviceName,        GET_DEVICE_TYPE_NAME(ourAttachedDevice->DeviceType)));

//    // Detach us from the object just below us    // Cleanup and delete the object    //

SfCleanupMountedDevice(ourAttachedDevice);    IoDetachDevice(DeviceObject);    IoDeleteDevice(ourAttachedDevice);

return;   }

//   // Look at the next device up in the attachment chain   //

DeviceObject = ourAttachedDevice;   ourAttachedDevice = ourAttachedDevice->AttachedDevice;  } }

#if WINVER >= 0x0501 NTSTATUS SfEnumerateFileSystemVolumes(  IN PDEVICE_OBJECT FSDeviceObject,  IN PUNICODE_STRING Name  ) /*++

Routine Description:

Enumerate all the mounted devices that currently exist for the given file  system and attach to them.  We do this because this filter could be loaded  at any time and there might already be mounted volumes for this file system.

Arguments:

FSDeviceObject - The device object for the file system we want to enumerate

Name - An already initialized unicode string used to retrieve names    This is passed in to reduce the number of strings buffers on    the stack.

Return Value:

The status of the operation

--*/ {  PDEVICE_OBJECT newDeviceObject;  PSFILTER_DEVICE_EXTENSION newDevExt;  PDEVICE_OBJECT *devList;  PDEVICE_OBJECT storageStackDeviceObject;  NTSTATUS status;  ULONG numDevices;  ULONG i;  BOOLEAN isShadowCopyVolume;

PAGED_CODE();

//  // Find out how big of an array we need to allocate for the  // mounted device list.  //

status = (gSfDynamicFunctions.EnumerateDeviceObjectList)(      FSDeviceObject->DriverObject,      NULL,      0,      &numDevices);

//  // We only need to get this list of there are devices.  If we  // don't get an error there are no devices so go on.  //

if (!NT_SUCCESS(status)) {

ASSERT(STATUS_BUFFER_TOO_SMALL == status);

//   // Allocate memory for the list of known devices   //

numDevices += 8;  // grab a few extra slots

devList = ExAllocatePoolWithTag(NonPagedPool,            (numDevices * sizeof(PDEVICE_OBJECT)),            SFLT_POOL_TAG);   if (NULL == devList) {

return STATUS_INSUFFICIENT_RESOURCES;   }

//   // Now get the list of devices.  If we get an error again   // something is wrong, so just fail.   //

ASSERT(NULL != gSfDynamicFunctions.EnumerateDeviceObjectList);   status = (gSfDynamicFunctions.EnumerateDeviceObjectList)(       FSDeviceObject->DriverObject,       devList,       (numDevices * sizeof(PDEVICE_OBJECT)),       &numDevices);

if (!NT_SUCCESS(status))  {

ExFreePool(devList);    return status;   }

//   // Walk the given list of devices and attach to them if we should.   //

for (i=0; i < numDevices; i++) {

//    // Initialize state so we can cleanup properly    //

storageStackDeviceObject = NULL;

try {

//     // Do not attach if:     // - This is the control device object (the one passed in)     // - The device type does not match     // - We are already attached to it.     //

if ((devList[i] == FSDeviceObject) ||      (devList[i]->DeviceType != FSDeviceObject->DeviceType) ||      SfIsAttachedToDevice(devList[i], NULL)) {

leave;     }

//     // See if this device has a name.  If so, then it must     // be a control device so don't attach to it.  This handles     // drivers with more then one control device (like FastFat).     //

SfGetBaseDeviceObjectName(devList[i], Name);

if (Name->Length > 0) {

leave;     }

//     // Get the real (disk,storage stack) device object associated     // with this file system device object.  Only try to attach     // if we have a disk device object.     //

ASSERT(NULL != gSfDynamicFunctions.GetDiskDeviceObject);     status = (gSfDynamicFunctions.GetDiskDeviceObject)(devList[i],                  &storageStackDeviceObject);

if (!NT_SUCCESS(status)) {

leave;     }

//     // Determine if this is a shadow copy volume.  If so don't     // attach to it.     // NOTE:  There is no reason sfilter shouldn't attach to these     //  volumes, this is simply a sample of how to not     //  attach if you don't want to     //

status = SfIsShadowCopyVolume (storageStackDeviceObject,             &isShadowCopyVolume);

if (NT_SUCCESS(status) &&      isShadowCopyVolume &&      !FlagOn(SfDebug,SFDEBUG_ATTACH_TO_SHADOW_COPIES)) {

UNICODE_STRING shadowDeviceName;      WCHAR shadowNameBuffer[MAX_DEVNAME_LENGTH];

//      // Get the name for the debug display      //

RtlInitEmptyUnicodeString(&shadowDeviceName,             shadowNameBuffer,             sizeof(shadowNameBuffer));

SfGetObjectName(storageStackDeviceObject,           &shadowDeviceName);

SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,           ("SFilter!SfEnumerateFileSystemVolumes   Not attaching to Volume %p /"%wZ/", shadow copy volume/n",          storageStackDeviceObject,          &shadowDeviceName));

leave;     }

//     // Allocate a new device object to attach with     //

status = IoCreateDevice(gSFilterDriverObject,            sizeof(SFILTER_DEVICE_EXTENSION),            NULL,            devList[i]->DeviceType,            0,            FALSE,            &newDeviceObject);

if (!NT_SUCCESS(status)) {

leave;     }

//     // Set disk device object     //

newDevExt = newDeviceObject->DeviceExtension;

RtlZeroMemory(newDevExt, sizeof(SFILTER_DEVICE_EXTENSION));         newDevExt->StorageStackDeviceObject = storageStackDeviceObject;       //     // Set storage stack device name     //

RtlInitEmptyUnicodeString(&newDevExt->DeviceName,             newDevExt->DeviceNameBuffer,             sizeof(newDevExt->DeviceNameBuffer));

SfGetObjectName(storageStackDeviceObject,         &newDevExt->DeviceName);

ExInitializeFastMutex(&newDevExt->FsCtxTableMutex);     RtlInitializeGenericTable(&newDevExt->FsCtxTable,      SfGenericCompareRoutine,      SfGenericAllocateRoutine,      SfGenericFreeRoutine,      NULL      );

//     // We have done a lot of work since the last time     // we tested to see if we were already attached     // to this device object.  Test again, this time     // with a lock, and attach if we are not attached.     // The lock is used to atomically test if we are     // attached, and then do the attach.     //

ExAcquireFastMutex(&gSfilterAttachLock);

if (!SfIsAttachedToDevice(devList[i], NULL)) {

//      // Attach to volume.      //

status = SfAttachToMountedDevice(devList[i],                newDeviceObject);           if (!NT_SUCCESS(status)) {

//       // The attachment failed, cleanup.  Note that       // we continue processing so we will cleanup       // the reference counts and try to attach to       // the rest of the volumes.       //       // One of the reasons this could have failed       // is because this volume is just being       // mounted as we are attaching and the       // DO_DEVICE_INITIALIZING flag has not yet       // been cleared.  A filter could handle       // this situation by pausing for a short       // period of time and retrying the attachment a       // limited number of times.       //

SfCleanupMountedDevice(newDeviceObject);       IoDeleteDevice(newDeviceObject);      }

} else {

//      // We were already attached, cleanup this      // device object.      //

SfCleanupMountedDevice(newDeviceObject);      IoDeleteDevice(newDeviceObject);     }

//     // Release the lock     //

ExReleaseFastMutex(&gSfilterAttachLock);

} finally {

//     // Remove reference added by IoGetDiskDeviceObject.     // We only need to hold this reference until we are     // successfully attached to the current volume.  Once     // we are successfully attached to devList[i], the     // IO Manager will make sure that the underlying     // storageStackDeviceObject will not go away until     // the file system stack is torn down.     //

if (storageStackDeviceObject != NULL) {

ObDereferenceObject(storageStackDeviceObject);     }

//     // Dereference the object (reference added by     // IoEnumerateDeviceObjectList)     //

ObDereferenceObject(devList[i]);    }   }

//   // We are going to ignore any errors received while attaching.  We   // simply won't be attached to those volumes if we get an error   //

status = STATUS_SUCCESS;

//   // Free the memory we allocated for the list   //

ExFreePool(devList);  }

return status; } #endif

NTSTATUS SfAttachToMountedDevice(  IN PDEVICE_OBJECT DeviceObject,  IN PDEVICE_OBJECT SFilterDeviceObject  ) /*++

Routine Description:

This will attach to a DeviceObject that represents a mounted volume.

Arguments:

DeviceObject - The device to attach to

SFilterDeviceObject - Our device object we are going to attach

Return Value:

Status of the operation

--*/ {   PSFILTER_DEVICE_EXTENSION newDevExt = SFilterDeviceObject->DeviceExtension;  NTSTATUS status;  ULONG i;

PAGED_CODE();  ASSERT(IS_MY_DEVICE_OBJECT(SFilterDeviceObject)); #if WINVER >= 0x0501  ASSERT(!SfIsAttachedToDevice (DeviceObject, NULL)); #endif

//  // Propagate flags from Device Object we are trying to attach to.  // Note that we do this before the actual attachment to make sure  // the flags are properly set once we are attached (since an IRP  // can come in immediately after attachment but before the flags would  // be set).  //

if (FlagOn(DeviceObject->Flags, DO_BUFFERED_IO)) {

SetFlag(SFilterDeviceObject->Flags, DO_BUFFERED_IO);  }

if (FlagOn(DeviceObject->Flags, DO_DIRECT_IO)) {

SetFlag(SFilterDeviceObject->Flags, DO_DIRECT_IO);  }

//  // It is possible for this attachment request to fail because this device  // object has not finished initializing.  This can occur if this filter  // loaded just as this volume was being mounted.  //

for (i=0; i < 8; i++) {   LARGE_INTEGER interval;

//   // Attach our device object to the given device object   // The only reason this can fail is if someone is trying to dismount   // this volume while we are attaching to it.   //

status = SfAttachDeviceToDeviceStack(SFilterDeviceObject,              DeviceObject,              &newDevExt->AttachedToDeviceObject);   if (NT_SUCCESS(status)) {

//    // Finished all initialization of the new device object,  so clear the    // initializing flag now.  This allows other filters to now attach    // to our device object.    //

ClearFlag(SFilterDeviceObject->Flags, DO_DEVICE_INITIALIZING);

//    // Display the name    //

SF_LOG_PRINT(SFDEBUG_DISPLAY_ATTACHMENT_NAMES,         ("SFilter!SfAttachToMountedDevice:    Attaching to volume  %p /"%wZ/"/n",        newDevExt->AttachedToDeviceObject,        &newDevExt->DeviceName));

return STATUS_SUCCESS;   }

//   // Delay, giving the device object a chance to finish its   // initialization so we can try again   //

interval.QuadPart = (500 * DELAY_ONE_MILLISECOND);   // delay 1/2 second   KeDelayExecutionThread(KernelMode, FALSE, &interval);  }

return status; }

VOID SfCleanupMountedDevice(  IN PDEVICE_OBJECT DeviceObject  ) /*++

Routine Description:

This cleans up any necessary data in the device extension to prepare for  this memory to be freed.

Arguments:

DeviceObject - The device we are cleaning up

Return Value:

None

--*/ {   PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;    UNREFERENCED_PARAMETER(DeviceObject);  ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

if (DevExt->StorageStackDeviceObject)  {   ExAcquireFastMutex(&DevExt->FsCtxTableMutex);

while (!RtlIsGenericTableEmpty(&DevExt->FsCtxTable))   {    PVOID Element = RtlGetElementGenericTable(     &DevExt->FsCtxTable,     0     );    if (Element)    {     RtlDeleteElementGenericTable(      &DevExt->FsCtxTable,      Element      );    }   }

ExReleaseFastMutex(&DevExt->FsCtxTableMutex);  } }

VOID SfGetObjectName(  IN PVOID Object,  IN OUT PUNICODE_STRING Name  ) /*++

Routine Description:

This routine will return the name of the given object.  If a name can not be found an empty string will be returned.

Arguments:

Object - The object whose name we want

Name - A unicode string that is already initialized with a buffer that    receives the name of the object.

Return Value:

None

--*/ {  NTSTATUS status;  CHAR nibuf[512];  // buffer that receives NAME information and name  POBJECT_NAME_INFORMATION nameInfo = (POBJECT_NAME_INFORMATION)nibuf;  ULONG retLength;

status = ObQueryNameString(Object, nameInfo, sizeof(nibuf), &retLength);

Name->Length = 0;  if (NT_SUCCESS(status)) {

RtlCopyUnicodeString(Name, &nameInfo->Name);  } }

// // VERSION NOTE: // // This helper routine is only needed when enumerating all volumes in the // system, which is only supported on Windows XP and later. //

#if WINVER >= 0x0501 VOID SfGetBaseDeviceObjectName(  IN PDEVICE_OBJECT DeviceObject,  IN OUT PUNICODE_STRING Name  ) /*++

Routine Description:

This locates the base device object in the given attachment chain and then  returns the name of that object.

If no name can be found, an empty string is returned.

Arguments:

Object - The object whose name we want

Name - A unicode string that is already initialized with a buffer that    receives the name of the device object.

Return Value:

None

--*/ {  //  // Get the base file system device object  //

ASSERT(NULL != gSfDynamicFunctions.GetDeviceAttachmentBaseRef);  DeviceObject = (gSfDynamicFunctions.GetDeviceAttachmentBaseRef)(DeviceObject);

//  // Get the name of that object  //

SfGetObjectName(DeviceObject, Name);

//  // Remove the reference added by IoGetDeviceAttachmentBaseRef  //

ObDereferenceObject(DeviceObject); } #endif

PUNICODE_STRING SfGetFileName(  IN PFILE_OBJECT FileObject,  IN NTSTATUS CreateStatus,  IN OUT PGET_NAME_CONTROL NameControl  ) /*++

Routine Description:

This routine will try and get the name of the given file object.  This  is guaranteed to always return a printable string (though it may be NULL).  This will allocate a buffer if it needs to.

Arguments:  FileObject - the file object we want the name for

CreateStatus - status of the create operation

NameControl - control structure used for retrieving the name.  It keeps   track if a buffer was allocated or if we are using the internal   buffer.

Return Value:

Pointer to the unicode string with the name

--*/ {  POBJECT_NAME_INFORMATION nameInfo;  NTSTATUS status;  ULONG size;  ULONG bufferSize;

//  // Mark we have not allocated the buffer  //

NameControl->allocatedBuffer = NULL;

//  // Use the small buffer in the structure (that will handle most cases)  // for the name  //

nameInfo = (POBJECT_NAME_INFORMATION)NameControl->smallBuffer;  bufferSize = sizeof(NameControl->smallBuffer);

//  // If the open succeeded, get the name of the file, if it  // failed, get the name of the device.  //    status = ObQueryNameString(       (NT_SUCCESS(CreateStatus) ?      (PVOID)FileObject :      (PVOID)FileObject->DeviceObject),       nameInfo,       bufferSize,       &size);

//  // See if the buffer was to small  //

if (status == STATUS_BUFFER_OVERFLOW) {

//   // The buffer was too small, allocate one big enough   //

bufferSize = size + sizeof(WCHAR);

NameControl->allocatedBuffer = ExAllocatePoolWithTag(            NonPagedPool,            bufferSize,            SFLT_POOL_TAG);

if (NULL == NameControl->allocatedBuffer) {

//    // Failed allocating a buffer, return an empty string for the name    //

RtlInitEmptyUnicodeString(     (PUNICODE_STRING)&NameControl->smallBuffer,     (PWCHAR)(NameControl->smallBuffer + sizeof(UNICODE_STRING)),     (USHORT)(sizeof(NameControl->smallBuffer) - sizeof(UNICODE_STRING)));

return (PUNICODE_STRING)&NameControl->smallBuffer;   }

//   // Set the allocated buffer and get the name again   //

nameInfo = (POBJECT_NAME_INFORMATION)NameControl->allocatedBuffer;

status = ObQueryNameString(        FileObject,        nameInfo,        bufferSize,        &size);  }

//  // If we got a name and an error opening the file then we  // just received the device name.  Grab the rest of the name  // from the FileObject (note that this can only be done if being called  // from Create).  This only happens if we got an error back from the  // create.  //

if (NT_SUCCESS(status) &&      !NT_SUCCESS(CreateStatus)) {

ULONG newSize;   PCHAR newBuffer;   POBJECT_NAME_INFORMATION newNameInfo;

//   // Calculate the size of the buffer we will need to hold   // the combined names   //

newSize = size + FileObject->FileName.Length;

//   // If there is a related file object add in the length   // of that plus space for a separator   //

if (NULL != FileObject->RelatedFileObject) {

newSize += FileObject->RelatedFileObject->FileName.Length +       sizeof(WCHAR);   }

//   // See if it will fit in the existing buffer   //

if (newSize > bufferSize) {

//    // It does not fit, allocate a bigger buffer    //

newBuffer = ExAllocatePoolWithTag(          NonPagedPool,          newSize,          SFLT_POOL_TAG);

if (NULL == newBuffer) {

//     // Failed allocating a buffer, return an empty string for the name     //

RtlInitEmptyUnicodeString(      (PUNICODE_STRING)&NameControl->smallBuffer,      (PWCHAR)(NameControl->smallBuffer + sizeof(UNICODE_STRING)),      (USHORT)(sizeof(NameControl->smallBuffer) - sizeof(UNICODE_STRING)));

return (PUNICODE_STRING)&NameControl->smallBuffer;    }

//    // Now initialize the new buffer with the information    // from the old buffer.    //

newNameInfo = (POBJECT_NAME_INFORMATION)newBuffer;

RtlInitEmptyUnicodeString(     &newNameInfo->Name,     (PWCHAR)(newBuffer + sizeof(OBJECT_NAME_INFORMATION)),     (USHORT)(newSize - sizeof(OBJECT_NAME_INFORMATION)));

RtlCopyUnicodeString(&newNameInfo->Name,           &nameInfo->Name);

//    // Free the old allocated buffer (if there is one)    // and save off the new allocated buffer address.  It    // would be very rare that we should have to free the    // old buffer because device names should always fit    // inside it.    //

if (NULL != NameControl->allocatedBuffer) {

ExFreePool(NameControl->allocatedBuffer);    }

//    // Readjust our pointers    //

NameControl->allocatedBuffer = newBuffer;    bufferSize = newSize;    nameInfo = newNameInfo;

} else {

//    // The MaximumLength was set by ObQueryNameString to    // one char larger then the length.  Set it to the    // true size of the buffer (so we can append the names)    //

nameInfo->Name.MaximumLength = (USHORT)(bufferSize -           sizeof(OBJECT_NAME_INFORMATION));   }

//   // If there is a related file object, append that name   // first onto the device object along with a separator   // character   //

if (NULL != FileObject->RelatedFileObject) {

RtlAppendUnicodeStringToString(      &nameInfo->Name,      &FileObject->RelatedFileObject->FileName);

RtlAppendUnicodeToString(&nameInfo->Name, L"//");   }

//   // Append the name from the file object   //

RtlAppendUnicodeStringToString(     &nameInfo->Name,     &FileObject->FileName);

ASSERT(nameInfo->Name.Length <= nameInfo->Name.MaximumLength);  }

//  // Return the name  //

return &nameInfo->Name; }

VOID SfGetFileNameCleanup(  IN OUT PGET_NAME_CONTROL NameControl  ) /*++

Routine Description:

This will see if a buffer was allocated and will free it if it was

Arguments:

NameControl - control structure used for retrieving the name.  It keeps   track if a buffer was allocated or if we are using the internal   buffer.

Return Value:

None

--*/ {

if (NULL != NameControl->allocatedBuffer) {

ExFreePool(NameControl->allocatedBuffer);   NameControl->allocatedBuffer = NULL;  } }

// // VERSION NOTE: // // In Windows 2000, the APIs to safely walk an arbitrary file system device // stack were not supported.  If we can guarantee that a device stack won't // be torn down during the walking of the device stack, we can walk from // the base file system's device object up to the top of the device stack // to see if we are attached.  We know the device stack will not go away if // we are in the process of processing a mount request OR we have a file object // open on this device. // // In Windows XP and later, the IO Manager provides APIs that will allow us to // walk through the chain safely using reference counts to protect the device // object from going away while we are inspecting it.  This can be done at any // time. // // MULTIVERSION NOTE: // // If built for Windows XP or later, this driver is built to run on // multiple versions.  When this is the case, we will test for the presence of // the new IO Manager routines that allow for a filter to safely walk the file // system device stack and use those APIs if they are present to determine if // we have already attached to this volume.  If these new IO Manager routines // are not present, we will assume that we are at the bottom of the file // system stack and walk up the stack looking for our device object. //

BOOLEAN SfIsAttachedToDevice(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  ) {

PAGED_CODE();

#if WINVER >= 0x0501  if (IS_WINDOWSXP_OR_LATER()) {

ASSERT(NULL != gSfDynamicFunctions.GetLowerDeviceObject &&     NULL != gSfDynamicFunctions.GetDeviceAttachmentBaseRef);     return SfIsAttachedToDeviceWXPAndLater(DeviceObject, AttachedDeviceObject);  } else { #endif

return SfIsAttachedToDeviceW2K(DeviceObject, AttachedDeviceObject);

#if WINVER >= 0x0501  } #endif }

BOOLEAN SfIsAttachedToDeviceW2K(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  ) /*++

Routine Description:

VERSION: Windows 2000

This routine walks up the device stack from the DeviceObject passed in  looking for a device object that belongs to our filter.

Note:  If AttachedDeviceObject is returned with a non-NULL value,    there is a reference on the AttachedDeviceObject that must    be cleared by the caller.

Arguments:

DeviceObject - The device chain we want to look through

AttachedDeviceObject - Set to the deviceObject which FileSpy    has previously attached to DeviceObject.

Return Value:

TRUE if we are attached, FALSE if not

--*/ {  PDEVICE_OBJECT currentDevice;

PAGED_CODE();

for (currentDevice = DeviceObject;    currentDevice != NULL;    currentDevice = currentDevice->AttachedDevice) {

if (IS_MY_DEVICE_OBJECT(currentDevice)) {

//    // We are attached.  If requested, return the found device object.    //

if (ARGUMENT_PRESENT(AttachedDeviceObject)) {

ObReferenceObject(currentDevice);     *AttachedDeviceObject = currentDevice;    }

return TRUE;   }  }

//  // We did not find ourselves on the attachment chain.  Return a NULL  // device object pointer (if requested) and return we did not find  // ourselves.  //    if (ARGUMENT_PRESENT(AttachedDeviceObject)) {

*AttachedDeviceObject = NULL;  }

return FALSE; }

#if WINVER >= 0x0501 BOOLEAN SfIsAttachedToDeviceWXPAndLater(  PDEVICE_OBJECT DeviceObject,  PDEVICE_OBJECT *AttachedDeviceObject OPTIONAL  ) /*++

Routine Description:

VERSION: Windows XP and later

This walks down the attachment chain looking for a device object that  belongs to this driver.  If one is found, the attached device object  is returned in AttachedDeviceObject.

Arguments:

DeviceObject - The device chain we want to look through

AttachedDeviceObject - The Sfilter device attached to this device.

Return Value:

TRUE if we are attached, FALSE if not

--*/ {  PDEVICE_OBJECT currentDevObj;  PDEVICE_OBJECT nextDevObj;

PAGED_CODE();    //  // Get the device object at the TOP of the attachment chain  //

ASSERT(NULL != gSfDynamicFunctions.GetAttachedDeviceReference);  currentDevObj = (gSfDynamicFunctions.GetAttachedDeviceReference)(DeviceObject);

//  // Scan down the list to find our device object.  //

do {     if (IS_MY_DEVICE_OBJECT(currentDevObj)) {

//    // We have found that we are already attached.  If we are    // returning the device object, leave it referenced else remove    // the reference.    //

if (ARGUMENT_PRESENT(AttachedDeviceObject)) {

*AttachedDeviceObject = currentDevObj;

} else {

ObDereferenceObject(currentDevObj);    }

return TRUE;   }

//   // Get the next attached object.  This puts a reference on   // the device object.   //

ASSERT(NULL != gSfDynamicFunctions.GetLowerDeviceObject);   nextDevObj = (gSfDynamicFunctions.GetLowerDeviceObject)(currentDevObj);

//   // Dereference our current device object, before   // moving to the next one.   //

ObDereferenceObject(currentDevObj);

currentDevObj = nextDevObj;    } while (NULL != currentDevObj);    //  // We did not find ourselves on the attachment chain.  Return a NULL  // device object pointer (if requested) and return we did not find  // ourselves.  //

if (ARGUMENT_PRESENT(AttachedDeviceObject)) {

*AttachedDeviceObject = NULL;  }

return FALSE; } #endif

VOID SfDriverReinitialization(     IN PDRIVER_OBJECT DriverObject,     IN PVOID Context,     IN ULONG Count     ) /*++

Routine Description:

This routine will load the rules into gRules   Arguments:

DriverObject - pointer to the driver object  Context - the param passed to IoRegisterDriverReinitialization  Count - reinitialize count   Return Value:

VOID.

--*/ {  NTSTATUS Status;

UNREFERENCED_PARAMETER(Count);

Status = SfLoadRules(&gRuleFileHandle);  if (!NT_SUCCESS(Status))  {   KdPrint(("SFilter!SfDriverReinitialization: SfLoadRules failed, Status=%08x/n", Status));   IoRegisterDriverReinitialization(DriverObject, SfDriverReinitialization, Context);  } }

NTSTATUS SfIsShadowCopyVolume(  IN PDEVICE_OBJECT StorageStackDeviceObject,  OUT PBOOLEAN IsShadowCopy  ) /*++

Routine Description:

This routine will determine if the given volume is for a ShadowCopy volume  or some other type of volume.

VERSION NOTE:

ShadowCopy volumes were introduced in Windows XP, therefore, if this  driver is running on W2K, we know that this is not a shadow copy volume.

Also note that in Windows XP, we need to test to see if the driver name  of this device object is /Driver/VolSnap in addition to seeing if this  device is read-only.  For Windows Server 2003, we can infer that  this is a ShadowCopy by looking for a DeviceType == FILE_DEVICE_VIRTUAL_DISK  and read-only volume.   Arguments:

StorageStackDeviceObject - pointer to the disk device object  IsShadowCopy - returns TRUE if this is a shadow copy, FALSE otherwise   Return Value:

The status of the operation.  If this operation fails IsShadowCopy is  always set to FALSE.

--*/ {

PAGED_CODE();

//  // Default to NOT a shadow copy volume  //

*IsShadowCopy = FALSE;

#if WINVER >= 0x0501  if (IS_WINDOWS2000()) { #endif

UNREFERENCED_PARAMETER(StorageStackDeviceObject);   return STATUS_SUCCESS;

#if WINVER >= 0x0501   }

if (IS_WINDOWSXP()) {

UNICODE_STRING volSnapDriverName;   WCHAR buffer[MAX_DEVNAME_LENGTH];   PUNICODE_STRING storageDriverName;   ULONG returnedLength;   NTSTATUS status;

//   // In Windows XP, all ShadowCopy devices were of type FILE_DISK_DEVICE.   // If this does not have a device type of FILE_DISK_DEVICE, then   // it is not a ShadowCopy volume.  Return now.   //

if (FILE_DEVICE_DISK != StorageStackDeviceObject->DeviceType) {

return STATUS_SUCCESS;   }

//   // Unfortunately, looking for the FILE_DEVICE_DISK isn't enough.  We   // need to find out if the name of this driver is /Driver/VolSnap as   // well.   //

storageDriverName = (PUNICODE_STRING) buffer;   RtlInitEmptyUnicodeString(storageDriverName,          Add2Ptr(storageDriverName, sizeof(UNICODE_STRING)),          sizeof(buffer) - sizeof(UNICODE_STRING));

status = ObQueryNameString(StorageStackDeviceObject,          (POBJECT_NAME_INFORMATION)storageDriverName,          storageDriverName->MaximumLength,          &returnedLength);

if (!NT_SUCCESS(status)) {

return status;   }

RtlInitUnicodeString(&volSnapDriverName, L"//Driver//VolSnap");

if (RtlEqualUnicodeString(storageDriverName, &volSnapDriverName, TRUE)) {

//    // This is a ShadowCopy volume, so set our return parameter to true.    //

*IsShadowCopy = TRUE;

} else {

//    // This is not a ShadowCopy volume, but IsShadowCopy is already    // set to FALSE.  Fall through to return to the caller.    //

NOTHING;   }

return STATUS_SUCCESS;    } else {

PIRP irp;   KEVENT event;   IO_STATUS_BLOCK iosb;   NTSTATUS status;

//   // For Windows Server 2003 and later, it is sufficient to test for a   // device type fo FILE_DEVICE_VIRTUAL_DISK and that the device   // is read-only to identify a ShadowCopy.   //

//   // If this does not have a device type of FILE_DEVICE_VIRTUAL_DISK, then   // it is not a ShadowCopy volume.  Return now.   //

if (FILE_DEVICE_VIRTUAL_DISK != StorageStackDeviceObject->DeviceType) {

return STATUS_SUCCESS;   }

//   // It has the correct device type, see if it is marked as read only.   //   // NOTE:  You need to be careful which device types you do this operation   //  on.  It is accurate for this type but for other device   //  types it may return misleading information.  For example the   //  current microsoft cdrom driver always returns CD media as   //  readonly, even if the media may be writable.  On other types   //  this state may change.   //

KeInitializeEvent(&event, NotificationEvent, FALSE);

irp = IoBuildDeviceIoControlRequest(IOCTL_DISK_IS_WRITABLE,             StorageStackDeviceObject,             NULL,             0,             NULL,             0,             FALSE,             &event,             &iosb);

//   // If we could not allocate an IRP, return an error   //

if (irp == NULL) {

return STATUS_INSUFFICIENT_RESOURCES;   }

//   // Call the storage stack and see if this is readonly   //

status = IoCallDriver(StorageStackDeviceObject, irp);

if (status == STATUS_PENDING) {

(VOID)KeWaitForSingleObject(&event,            Executive,            KernelMode,            FALSE,            NULL);

status = iosb.Status;   }

//   // If the media is write protected then this is a shadow copy volume   //

if (STATUS_MEDIA_WRITE_PROTECTED == status) {

*IsShadowCopy = TRUE;    status = STATUS_SUCCESS;   }

//   // Return the status of the IOCTL.  IsShadowCopy is already set to FALSE   // which is what we want if STATUS_SUCCESS was returned or if an error   // was returned.   //

return status;  } #endif }

BOOLEAN SfDissectFileName(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  OUT PWSTR FileName  ) /*++ Arguments:

DeviceObject - Pointer to the device object for this driver.

Irp - Pointer to the request packet representing the I/O request.

FileName - Copy valid file name.

Return Value:

return TRUE file is valid,otherwize return FALSE.

--*/ {  PSFILTER_DEVICE_EXTENSION DeviceExtension = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);  PFILE_OBJECT FileObject = IrpSp->FileObject;  PFILE_OBJECT RelatedFileObject = FileObject->RelatedFileObject;  ULONG Length;    if (!FileObject->FileName.Buffer || (FileObject->FileName.Length == 0))  {   return FALSE;  }

RelatedFileObject = FileObject->RelatedFileObject;    // file format: 123.txt  FileName[0] = DeviceExtension->DriveLetter;  FileName[1] = L':';  if (FileObject->FileName.Buffer[0] != L'//' && RelatedFileObject && RelatedFileObject->FileName.Length)  {   if ((RelatedFileObject->FileName.Length + FileObject->FileName.Length) > MAX_PATH * sizeof(WCHAR))   {    return FALSE;   }

RtlCopyMemory(FileName + 2, RelatedFileObject->FileName.Buffer, RelatedFileObject->FileName.Length);     Length = 2 + (RelatedFileObject->FileName.Length >> 1);   if (FileName[Length - 1] != L'//')   {    FileName[Length] = L'//';    Length ++;   }     RtlCopyMemory(FileName + Length, FileObject->FileName.Buffer, FileObject->FileName.Length);   Length = (FileObject->FileName.Length >> 1) + Length;  }  else  {   // file format: /123.txt   RtlCopyMemory(FileName + 2, FileObject->FileName.Buffer, FileObject->FileName.Length);   Length = (FileObject->FileName.Length >> 1) + 2;  }

FileName[Length] = L'/0';

// trim right '/'  while ((Length > 3) && (FileName[Length - 1] == L'//') && (FileName[Length - 2] != L':'))  {   FileName[Length] = L'/0';   -- Length;  }    return TRUE; }

RTL_GENERIC_COMPARE_RESULTS SfGenericCompareRoutine(  IN PRTL_GENERIC_TABLE Table,  IN PVOID FirstStruct,  IN PVOID SecondStruct  ) {  PFILE_CONTEXT FirstFileCtx = (PFILE_CONTEXT) FirstStruct;  PFILE_CONTEXT SecondFileCtx = (PFILE_CONTEXT) SecondStruct;

UNREFERENCED_PARAMETER(Table);

if (FirstFileCtx->FsContext < SecondFileCtx->FsContext)   return GenericLessThan;  else if (FirstFileCtx->FsContext > SecondFileCtx->FsContext)   return GenericGreaterThan;  else   return GenericEqual; }

PVOID SfGenericAllocateRoutine(  IN PRTL_GENERIC_TABLE Table,  IN CLONG ByteSize  ) {  PVOID Buffer = NULL;

UNREFERENCED_PARAMETER(Table);  UNREFERENCED_PARAMETER(ByteSize);

ASSERT(ByteSize <= FSCTX_GENERIC_TABLE_POOL_SIZE);

Buffer = ExAllocateFromPagedLookasideList(&gFsCtxLookAsideList);  if (Buffer)   RtlZeroMemory(Buffer, FSCTX_GENERIC_TABLE_POOL_SIZE);    return Buffer; }

VOID SfGenericFreeRoutine(  IN PRTL_GENERIC_TABLE Table,  IN PVOID Buffer  ) {  UNREFERENCED_PARAMETER(Table);

ExFreeToPagedLookasideList(&gFsCtxLookAsideList, Buffer); }

NTSTATUS SfQueryCompletion (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PKEVENT SynchronizingEvent  ) /*++

Routine Description:

This routine does the cleanup necessary once the query request completed  by the file system.   Arguments:

DeviceObject - This will be NULL since we originated this   Irp.

Irp - The io request structure containing the information   about the current state of our file name query.

SynchronizingEvent - The event to signal to notify the   originator of this request that the operation is   complete.

Return Value:

Returns STATUS_MORE_PROCESSING_REQUIRED so that IO Manager  will not try to free the Irp again.

--*/ {

UNREFERENCED_PARAMETER(DeviceObject);    //  // Make sure that the Irp status is copied over to the user's  // IO_STATUS_BLOCK so that the originator of this irp will know  // the final status of this operation.  //

ASSERT(NULL != Irp->UserIosb);  *Irp->UserIosb = Irp->IoStatus;

//  // Signal SynchronizingEvent so that the originator of this  // Irp know that the operation is completed.  //

KeSetEvent(SynchronizingEvent, IO_NO_INCREMENT, FALSE);

//  // We are now done, so clean up the irp that we allocated.  //

IoFreeIrp(Irp);

//  // If we return STATUS_SUCCESS here, the IO Manager will  // perform the cleanup work that it thinks needs to be done  // for this IO operation.  This cleanup work includes:  // * Copying data from the system buffer to the user's buffer  //  if this was a buffered IO operation.  // * Freeing any MDLs that are in the Irp.  // * Copying the Irp->IoStatus to Irp->UserIosb so that the  //  originator of this irp can see the final status of the  //  operation.  // * If this was an asynchronous request or this was a  //  synchronous request that got pending somewhere along the  //  way, the IO Manager will signal the Irp->UserEvent, if one  //  exists, otherwise it will signal the FileObject->Event.  //  (This can have REALLY bad implications if the irp originator  // did not an Irp->UserEvent and the irp originator is not  // waiting on the FileObject->Event.  It would not be that  // farfetched to believe that someone else in the system is  // waiting on FileObject->Event and who knows who will be  // awoken as a result of the IO Manager signaling this event.  //  // Since some of these operations require the originating thread's  // context (e.g., the IO Manager need the UserBuffer address to  // be valid when copy is done), the IO Manager queues this work  // to an APC on the Irp's originating thread.  //  // Since FileSpy allocated and initialized this irp, we know  // what cleanup work needs to be done.  We can do this cleanup  // work more efficiently than the IO Manager since we are handling  // a very specific case.  Therefore, it is better for us to  // perform the cleanup work here then free the irp than passing  // control back to the IO Manager to do this work.  //  // By returning STATUS_MORE_PROCESS_REQUIRED, we tell the IO Manager  // to stop processing this irp until it is told to restart processing  // with a call to IoCompleteRequest.  Since the IO Manager has  // already performed all the work we want it to do on this  // irp, we do the cleanup work, return STATUS_MORE_PROCESSING_REQUIRED,  // and ask the IO Manager to resume processing by calling  // IoCompleteRequest.  //

return STATUS_MORE_PROCESSING_REQUIRED; }

NTSTATUS SfQueryFileSystemForFileName (  IN PFILE_OBJECT FileObject,  IN PDEVICE_OBJECT NextDeviceObject,  IN ULONG FileNameInfoLength,  OUT PFILE_NAME_INFORMATION FileNameInfo,  OUT PULONG ReturnedLength  ) /*++

Routine Description:

This routine rolls an irp to query the name of the  FileObject parameter from the base file system.

Note:  ObQueryNameString CANNOT be used here because it    would cause recursive lookup of the file name for FileObject.    Arguments:

FileObject - the file object for which we want the name.  NextDeviceObject - the device object for the next driver in the   stack.  This is where we want to start our request   for the name of FileObject.  FileNameInfoLength - the length in bytes of FileNameInfo   parameter.  FileNameInfo - the buffer that will be receive the name   information.  This must be memory that safe to write   to from kernel space.  ReturnedLength - the number of bytes written to FileNameInfo.   Return Value:

Returns the status of the operation.   --*/ {  PIRP Irp;  PIO_STACK_LOCATION IrpSp;  KEVENT Event;  IO_STATUS_BLOCK IoStatus;  NTSTATUS Status;

PAGED_CODE();

Irp = IoAllocateIrp(NextDeviceObject->StackSize, FALSE);  if (!Irp)   return STATUS_INSUFFICIENT_RESOURCES;

//  // Set our current thread as the thread for this  // Irp so that the IO Manager always knows which  // thread to return to if it needs to get back into  // the context of the thread that originated this  // Irp.  //   Irp->Tail.Overlay.Thread = PsGetCurrentThread();

//  // Set that this Irp originated from the kernel so that  // the IO Manager knows that the buffers do not  // need to be probed.  //  Irp->RequestorMode = KernelMode;

//  // Initialize the UserIosb and UserEvent in the  //  IoStatus.Status = STATUS_SUCCESS;  IoStatus.Information = 0;

Irp->UserIosb = &IoStatus;  Irp->UserEvent = NULL;  // already zeroed

//  // Set the IRP_SYNCHRONOUS_API to denote that this  // is a synchronous IO request.  //  Irp->Flags = IRP_SYNCHRONOUS_API;

IrpSp = IoGetNextIrpStackLocation(Irp);  IrpSp->MajorFunction = IRP_MJ_QUERY_INFORMATION;  IrpSp->FileObject = FileObject;

//  // Setup the parameters for IRP_MJ_QUERY_INFORMATION.  // The buffer we want to be filled in should be placed in  // the system buffer.  //  Irp->AssociatedIrp.SystemBuffer = FileNameInfo;

IrpSp->Parameters.QueryFile.Length = FileNameInfoLength;  IrpSp->Parameters.QueryFile.FileInformationClass = FileNameInformation;

//  // Set up the completion routine so that we know when our  // request for the file name is completed.  At that time,  // we can free the Irp.  //  KeInitializeEvent(&Event, NotificationEvent, FALSE);

IoSetCompletionRoutine(Irp,   SfQueryCompletion,   &Event,   TRUE,   TRUE,   TRUE   );

Status = IoCallDriver(NextDeviceObject, Irp);  if (STATUS_PENDING == Status)  {   (VOID) KeWaitForSingleObject(&Event,    Executive,    KernelMode,    FALSE,    NULL    );  }

ASSERT(KeReadStateEvent(&Event) || !NT_SUCCESS(IoStatus.Status));

*ReturnedLength = (ULONG) IoStatus.Information;  return IoStatus.Status; }

NTSTATUS SfIsEncryptFlagExist(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  OUT PBOOLEAN IsEncrypted,  OUT PVOID Data,  IN ULONG DataLength  ) {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  OBJECT_ATTRIBUTES ObjectAttributes;  UNICODE_STRING ObjectName;  HANDLE FileHandle;  IO_STATUS_BLOCK IoStatus;  NTSTATUS Status;  PWSTR EncryptFlagFile;

ASSERT(DeviceObject);  ASSERT(FileName);  ASSERT(IsEncrypted);

*IsEncrypted = FALSE;

//  // Is root dir ?  //  if (wcslen(FileName) <= 3)   return STATUS_SUCCESS;

EncryptFlagFile = ExAllocateFromPagedLookasideList(&gFileNameLookAsideList);  if (EncryptFlagFile == NULL)   return STATUS_INSUFFICIENT_RESOURCES;

EncryptFlagFile[0] = L'//';  EncryptFlagFile[1] = L'?';  EncryptFlagFile[2] = L'?';  EncryptFlagFile[3] = L'//';  EncryptFlagFile[4] = L'/0';    wcscat(EncryptFlagFile, FileName);

if (EncryptFlagFile[wcslen(EncryptFlagFile) - 1] == L'//')   EncryptFlagFile[wcslen(EncryptFlagFile) - 1] = L'/0';

wcscat(EncryptFlagFile, SF_ENCRYPT_POSTFIX);    RtlInitUnicodeString(&ObjectName, EncryptFlagFile);    InitializeObjectAttributes(&ObjectAttributes,   &ObjectName,   OBJ_KERNEL_HANDLE,   NULL,   NULL   );

Status = ZwCreateFile(&FileHandle,   FILE_READ_DATA | SYNCHRONIZE,   &ObjectAttributes,   &IoStatus,   NULL,   FILE_ATTRIBUTE_NORMAL,   0,   FILE_OPEN,   FILE_SYNCHRONOUS_IO_NONALERT,   NULL,   0   );  if (!NT_SUCCESS(Status))  {   if ((STATUS_NO_SUCH_FILE == Status) ||    (STATUS_OBJECT_NAME_NOT_FOUND == Status) ||    (STATUS_OBJECT_PATH_NOT_FOUND == Status))   {    Status = STATUS_SUCCESS;   }

ExFreeToPagedLookasideList(&gFileNameLookAsideList, EncryptFlagFile);

return Status;  }

*IsEncrypted = TRUE;

if (Data)  {   Status = ZwReadFile(FileHandle,    NULL,    NULL,    NULL,    &IoStatus,    Data,    DataLength,    NULL,    NULL    );  }    ZwClose(FileHandle);

ExFreeToPagedLookasideList(&gFileNameLookAsideList, EncryptFlagFile);

return Status; }

NTSTATUS SfIsFileNeedEncrypt(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  OUT PBOOLEAN NeedEncrypt  ) /*++

Arguments:  FileName - x:/xxx/.../xxx.xxx

--*/ {  UNREFERENCED_PARAMETER(DeviceObject);

if (POLICY_ENCRYPT == SfMatchRules(FileName))   *NeedEncrypt = TRUE;  else   *NeedEncrypt = FALSE;

return STATUS_SUCCESS; }

NTSTATUS SfSetFileEncrypted(  IN PDEVICE_OBJECT DeviceObject,  IN PCWSTR FileName,  IN BOOLEAN IsEncrypted,  IN PVOID Data,  IN ULONG DataLength  ) /*++

Arguments:  FileName - x:/xxx/.../xxx.xxx   --*/ {  PSFILTER_DEVICE_EXTENSION DevExt = (PSFILTER_DEVICE_EXTENSION) DeviceObject->DeviceExtension;  OBJECT_ATTRIBUTES ObjectAttributes;  UNICODE_STRING ObjectName;  HANDLE FileHandle = NULL;  IO_STATUS_BLOCK IoStatus;  NTSTATUS Status;  PWSTR EncryptFlagFile;  WCHAR *Pos1 = NULL, *Pos2 = NULL;

EncryptFlagFile = ExAllocateFromPagedLookasideList(&gFileNameLookAsideList);  if (EncryptFlagFile == NULL)   return STATUS_INSUFFICIENT_RESOURCES;

EncryptFlagFile[0] = L'//';  EncryptFlagFile[1] = L'?';  EncryptFlagFile[2] = L'?';  EncryptFlagFile[3] = L'//';  EncryptFlagFile[4] = L'/0';    wcscat(EncryptFlagFile, FileName);

if (EncryptFlagFile[wcslen(EncryptFlagFile) - 1] == L'//')   EncryptFlagFile[wcslen(EncryptFlagFile) - 1] = L'/0';

wcscat(EncryptFlagFile, SF_ENCRYPT_POSTFIX);

RtlInitUnicodeString(&ObjectName, EncryptFlagFile);    InitializeObjectAttributes(&ObjectAttributes,   &ObjectName,   OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,   NULL,   NULL   );

if (IsEncrypted)  {   Pos2 = wcsrchr(EncryptFlagFile, L'//');   if (!Pos2)   {    ExFreeToPagedLookasideList(&gFileNameLookAsideList, EncryptFlagFile);    return STATUS_INVALID_PARAMETER;   }     Pos1 = wcschr(&EncryptFlagFile[7], L'//');   if (Pos1)   {    while (Pos1 <= Pos2)    {     if (L'//' == *Pos1)     {      *Pos1 = L'/0';      Status = SfCreateFile(       EncryptFlagFile,       FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM,       FALSE       );      if (!NT_SUCCESS(Status))      {       if ((STATUS_OBJECT_NAME_EXISTS != Status) &&        (STATUS_OBJECT_NAME_COLLISION != Status))       {        ExFreeToPagedLookasideList(&gFileNameLookAsideList,         EncryptFlagFile);        return Status;       }      }      *Pos1 = L'//';     }       ++Pos1;    }   }

Status = ZwCreateFile(&FileHandle,    FILE_WRITE_DATA | SYNCHRONIZE,    &ObjectAttributes,    &IoStatus,    NULL,    FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM,    0,    FILE_OVERWRITE_IF,    FILE_SYNCHRONOUS_IO_NONALERT,    NULL,    0    );   if (NT_SUCCESS(Status))   {    if (Data)    {     Status = ZwWriteFile(FileHandle,      NULL,      NULL,      NULL,      &IoStatus,      Data,      DataLength,      NULL,      NULL      );    }

ZwClose(FileHandle);   }  }  else  {   Status = ZwDeleteFile(&ObjectAttributes);   if (!NT_SUCCESS(Status))   {    if ((STATUS_INVALID_PARAMETER == Status) ||     (STATUS_OBJECT_NAME_INVALID == Status) ||     (STATUS_OBJECT_NAME_NOT_FOUND == Status) ||     (STATUS_OBJECT_PATH_NOT_FOUND == Status) ||     (STATUS_OBJECT_PATH_SYNTAX_BAD == Status))    {     Status = STATUS_SUCCESS;    }   }  }

ExFreeToPagedLookasideList(&gFileNameLookAsideList, EncryptFlagFile);  return Status; }

NTSTATUS SfUpdateFileByFileObject(  IN PDEVICE_OBJECT DeviceObject,  IN PFILE_OBJECT FileObject  ) {  IO_STATUS_BLOCK IoStatus = {0};  NTSTATUS Status;  PUCHAR Buffer;  LARGE_INTEGER ByteOffset;  ULONG Offset = 0;  BOOLEAN EndOfFile = FALSE;

Buffer = ExAllocatePoolWithTag(PagedPool, 512, SFLT_POOL_TAG);  if (!Buffer)   return STATUS_INSUFFICIENT_RESOURCES;

ByteOffset.QuadPart = 0;

while (TRUE)  {   IoStatus.Status = STATUS_SUCCESS;   IoStatus.Information = 0;

Status = SfIssueReadWriteIrpSynchronously(    DeviceObject,    FileObject,    IRP_MJ_READ,    &IoStatus,    Buffer,    512,    &ByteOffset,    0    );   if (!NT_SUCCESS(Status))   {    if (STATUS_END_OF_FILE == Status)     Status = STATUS_SUCCESS;

break;   }

if (0 == IoStatus.Information)    break;

if (IoStatus.Information < 512)    EndOfFile = TRUE;

Status = SfIssueReadWriteIrpSynchronously(    DeviceObject,    FileObject,    IRP_MJ_WRITE,    &IoStatus,    Buffer,    IoStatus.Information,    &ByteOffset,    0    );   if (!NT_SUCCESS(Status))   {    if (STATUS_END_OF_FILE == Status)     Status = STATUS_SUCCESS;

break;   }

if (EndOfFile)    break;

ByteOffset.QuadPart += 512;  }

ExFreePool(Buffer);  return Status; }

NTSTATUS SfIssueReadWriteIrpSynchronously(  IN PDEVICE_OBJECT DeviceObject,  IN PFILE_OBJECT FileObject,  IN ULONG MajorFunction,  IN PIO_STATUS_BLOCK IoStatus,  IN PVOID Buffer,  IN ULONG Length,  IN PLARGE_INTEGER ByteOffset,  IN ULONG IrpFlags  ) {  PIRP Irp = NULL;  PIO_STACK_LOCATION IrpSp = NULL;  KEVENT Event;  NTSTATUS Status;

ASSERT((MajorFunction == IRP_MJ_READ) || (MajorFunction == IRP_MJ_WRITE));    KeInitializeEvent(&Event, NotificationEvent, FALSE);

Irp = IoBuildSynchronousFsdRequest(   MajorFunction,   DeviceObject,   Buffer,   Length,   ByteOffset,   &Event,   IoStatus   );  if (!Irp)   return STATUS_INSUFFICIENT_RESOURCES;

Irp->Flags |= IrpFlags;

IrpSp = IoGetNextIrpStackLocation(Irp);  IrpSp->FileObject = FileObject;

Status = IoCallDriver(DeviceObject, Irp);  if (STATUS_PENDING == Status)  {   KeWaitForSingleObject(&Event, Executive, KernelMode, FALSE, NULL);  }

return IoStatus->Status; }

NTSTATUS SfIssueCleanupIrpSynchronously(  IN PDEVICE_OBJECT NextDeviceObject,  IN PIRP Irp,  IN PFILE_OBJECT FileObject  ) {  PIO_STACK_LOCATION IrpSp = NULL;  IO_STATUS_BLOCK IoStatus;  KEVENT Event;

KeInitializeEvent(&Event, NotificationEvent, FALSE);  KeClearEvent(&FileObject->Event);

Irp->Tail.Overlay.OriginalFileObject = FileObject;  Irp->Tail.Overlay.Thread = PsGetCurrentThread();  Irp->Overlay.AsynchronousParameters.UserApcRoutine = (PIO_APC_ROUTINE) NULL;  Irp->RequestorMode = KernelMode;  Irp->UserEvent = &Event;  Irp->UserIosb = &IoStatus;  Irp->Flags = IRP_SYNCHRONOUS_API | IRP_CLOSE_OPERATION;

IrpSp = IoGetNextIrpStackLocation(Irp);  IrpSp->MajorFunction = IRP_MJ_CLEANUP;  IrpSp->FileObject = FileObject;

if (STATUS_PENDING == IoCallDriver(NextDeviceObject, Irp))  {   KeWaitForSingleObject(&Event, Executive, KernelMode, FALSE, NULL);  }

return IoStatus.Status; }

NTSTATUS SfCreateFile(  IN PCWSTR FileName,  IN ULONG FileAttributes,  IN BOOLEAN IsFile  ) /*++

Arguments:  FileName - /??/x:/xxx/.../xxx.xxx

--*/ {  HANDLE FileHandle = NULL;  OBJECT_ATTRIBUTES ObjectAttributes;  UNICODE_STRING ObjectName;  IO_STATUS_BLOCK IoStatus;  NTSTATUS Status;    RtlInitUnicodeString(&ObjectName, FileName);

InitializeObjectAttributes(   &ObjectAttributes,   &ObjectName,   OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,   NULL,   NULL   );

if (IsFile)  {   Status = ZwCreateFile(&FileHandle,    FILE_READ_ATTRIBUTES,    &ObjectAttributes,    &IoStatus,    NULL,    FileAttributes,    0,    FILE_OPEN_IF,    FILE_NON_DIRECTORY_FILE | FILE_SYNCHRONOUS_IO_NONALERT,    NULL,    0    );  }  else  {   Status = ZwCreateFile(&FileHandle,    FILE_READ_ATTRIBUTES,    &ObjectAttributes,    &IoStatus,    NULL,    FileAttributes,    0,    FILE_OPEN_IF,    FILE_DIRECTORY_FILE | FILE_SYNCHRONOUS_IO_NONALERT,    NULL,    0    );  }

if (NT_SUCCESS(Status))   ZwClose(FileHandle);

return Status; }

NTSTATUS SfRenameFile(  IN PWSTR SrcFileName,  IN PWSTR DstFileName  ) /*++

Arguments:  SrcFileName - /??/x:/xxx/.../xxx.xxx  DstFileName - /??/x:/xxx/.../xxx.xxx

--*/ {  HANDLE FileHandle = NULL;  OBJECT_ATTRIBUTES ObjectAttributes;  IO_STATUS_BLOCK IoStatus;  NTSTATUS Status;  PFILE_RENAME_INFORMATION RenameInfo = NULL;  UNICODE_STRING ObjectName;

RenameInfo = (PFILE_RENAME_INFORMATION) ExAllocatePoolWithTag(   NonPagedPool,   sizeof(FILE_RENAME_INFORMATION) + MAX_PATH * sizeof(WCHAR),   SFLT_POOL_TAG   );  if (RenameInfo == NULL)   return STATUS_INSUFFICIENT_RESOURCES;

RtlZeroMemory(RenameInfo, sizeof(FILE_RENAME_INFORMATION) + MAX_PATH * sizeof(WCHAR));  RenameInfo->FileNameLength = wcslen(DstFileName) * sizeof(WCHAR);  wcscpy(RenameInfo->FileName, DstFileName);  RenameInfo->ReplaceIfExists = 0;  RenameInfo->RootDirectory = NULL;

RtlInitUnicodeString(&ObjectName, SrcFileName);    InitializeObjectAttributes(   &ObjectAttributes,   &ObjectName,   OBJ_CASE_INSENSITIVE,   NULL,   NULL   );    Status = ZwCreateFile(   &FileHandle,   SYNCHRONIZE | DELETE,   &ObjectAttributes,   &IoStatus,   NULL,   0,   FILE_SHARE_READ,   FILE_OPEN,   FILE_SYNCHRONOUS_IO_NONALERT | FILE_NO_INTERMEDIATE_BUFFERING,   NULL,   0);  if (!NT_SUCCESS(Status))  {   ExFreePoolWithTag(RenameInfo, SFLT_POOL_TAG);   return Status;  }

Status = ZwSetInformationFile(   FileHandle,   &IoStatus,   RenameInfo,   sizeof(FILE_RENAME_INFORMATION) + MAX_PATH * sizeof(WCHAR),   FileRenameInformation   );  if (!NT_SUCCESS(Status))  {   ExFreePoolWithTag(RenameInfo, SFLT_POOL_TAG);   ZwClose(FileHandle);   return Status;  }

ZwClose(FileHandle);  return Status; }

NTSTATUS SfForwardIrpSyncronouslyCompletion (  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp,  IN PVOID Context  ) {  PKEVENT Event = Context;

UNREFERENCED_PARAMETER(DeviceObject);

ASSERT(IS_MY_DEVICE_OBJECT(DeviceObject));

if (Irp->PendingReturned)  {   KeSetEvent(Event, IO_NO_INCREMENT, FALSE);  }

return STATUS_MORE_PROCESSING_REQUIRED; }

NTSTATUS SfForwardIrpSyncronously(  IN PDEVICE_OBJECT DeviceObject,  IN PIRP Irp  ) {  KEVENT Event;  NTSTATUS Status;

KeInitializeEvent(&Event, NotificationEvent, FALSE);  IoCopyCurrentIrpStackLocationToNext(Irp);  IoSetCompletionRoutine(Irp, SfForwardIrpSyncronouslyCompletion, &Event, TRUE, TRUE, TRUE);  Status = IoCallDriver(DeviceObject, Irp);  if (STATUS_PENDING == Status)  {   KeWaitForSingleObject(&Event, Executive, KernelMode, FALSE, NULL);   Status = Irp->IoStatus.Status;  }  return Status; }

NTSTATUS SfLoadRules(  OUT PHANDLE FileHandle  ) {  UNICODE_STRING FileName;  IO_STATUS_BLOCK IoStatus;  FILE_STANDARD_INFORMATION StandardInfo;  ULONG Length;  OBJECT_ATTRIBUTES ObjectAttributes;  NTSTATUS Status;  PRULE Rule;    RtlInitUnicodeString(&FileName, RULE_FILE_NAME);    InitializeObjectAttributes(&ObjectAttributes,   &FileName,   OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,   NULL,   NULL   );

do  {   Status = ZwCreateFile(FileHandle,    (SYNCHRONIZE | FILE_READ_DATA),    &ObjectAttributes,    &IoStatus,    NULL,    FILE_ATTRIBUTE_NORMAL,    0,    FILE_OPEN,    FILE_SYNCHRONOUS_IO_NONALERT | FILE_NO_INTERMEDIATE_BUFFERING,    NULL,    0    );   if (!NT_SUCCESS(Status))   {    *FileHandle = NULL;    break;   }

Status = ZwQueryInformationFile(*FileHandle,    &IoStatus,    &StandardInfo,    sizeof(FILE_STANDARD_INFORMATION),    FileStandardInformation    );   if (!NT_SUCCESS(Status))   {    ZwClose(*FileHandle);    *FileHandle = NULL;    break;   }

Length = StandardInfo.EndOfFile.LowPart;   if (Length % sizeof(RULE) != 4)   {    Status = STATUS_INVALID_PARAMETER;    ZwClose(*FileHandle);    *FileHandle = NULL;    break;   }

Rule = (PRULE) ExAllocatePoolWithTag(NonPagedPool, Length - 4 + sizeof(RULE), SFLT_POOL_TAG);   if (!Rule)   {    Status = STATUS_INSUFFICIENT_RESOURCES;    ZwClose(*FileHandle);    *FileHandle = NULL;    break;   }      Status = ZwReadFile(*FileHandle,    NULL,    NULL,    NULL,    &IoStatus,    Rule,    Length,    NULL,    NULL    );   if ((!NT_SUCCESS(Status)) || (IoStatus.Information != Length))   {    ExFreePoolWithTag(Rule, SFLT_POOL_TAG);    Rule = NULL;    ZwClose(*FileHandle);    *FileHandle = NULL;    break;   }

ZwClose(*FileHandle);   *FileHandle = NULL; /*   {    PULONG Data = (PULONG) Rule;    ULONG CRC = 0;    ULONG i;    ULONG TmpLength = Length / 4;

for (i = 0; i < TmpLength - 1; ++i)     CRC += Data[i];

if (CRC != Data[TmpLength - 1])    {     Status = STATUS_INVALID_PARAMETER;     ExFreePoolWithTag(Rule, SFLT_POOL_TAG);     Rule = NULL;     break;    }   }  */   ((PRULE)((PUCHAR) Rule + Length - 4))->Policy = POLICY_END;

ExAcquireResourceSharedLite(&gRulesResource, TRUE);      if (gRules)       ExFreePool(gRules);   gRules = Rule;   ExReleaseResourceLite(&gRulesResource);

} while (FALSE);

return Status; }

ULONG SfMatchRules(  IN PCWSTR FileName  ) {  PRULE Rule;  PWSTR Pattern = NULL;  ULONG Policy = POLICY_NONE;

KeEnterCriticalRegion();     ExAcquireResourceSharedLite(&gRulesResource, TRUE);    Rule = gRules;  if (Rule == NULL)  {   ExReleaseResourceLite(&gRulesResource);   KeLeaveCriticalRegion();   return POLICY_NONE;  }

for (; Rule->Policy != POLICY_END; ++Rule)  {   Pattern = Rule->Pattern;   Pattern[MAX_PATH - 1] = L'/0';     if (!SfMatchWithPattern(Pattern, FileName))    continue;

Policy = Rule->Policy;   break;  }

ExReleaseResourceLite(&gRulesResource);  KeLeaveCriticalRegion();    return Policy; }

BOOLEAN SfMatchWithPattern(  IN PCWSTR Pattern,  IN PCWSTR Name  ) {     WCHAR Upcase;

if ((!Name) || (!Pattern))   return FALSE;       //     // End of pattern and name?     //     if ((!*Pattern) && (!*Name))         return TRUE;

if (!*Pattern) //Pattern is Empty, Name not Empty   return FALSE;

if (!*Name)//Name is Enpty, Pattern not Enpty   return SfMatchOkay(Pattern);

//     // If we hit a wild card, do recursion     //     if (*Pattern == L'*')  {   while (*Pattern == L'*')    Pattern++;

if (!*Pattern)    return TRUE;

while (*Name)   {             if (*Name >= L'a' && *Name <= L'z')                 Upcase = *Name - L'a' + L'A';             else                 Upcase = *Name;

//             // See if this substring matches             //             if ((*Pattern == Upcase) || (*Pattern == L'?'))    {                 if (SfMatchWithPattern(Pattern + 1, Name + 1))                     return TRUE;             }

//             // Try the next substring             //             Name++;         }

//         // See if match condition was met         //         return FALSE;     }

//     // Do straight compare until we hit a wild card     //     while (*Name && *Pattern != L'*')  {         if (*Name >= L'a' && *Name <= L'z')             Upcase = *Name - L'a' + L'A';         else             Upcase = *Name;

if ((*Pattern == Upcase) || (*Pattern == L'?'))   {             Pattern++;             Name++;         }   else             return FALSE;     }

//     // If not done, recurse     //     if (*Name) // *Pattern == '*'         return SfMatchWithPattern(Pattern, Name);

//     // Make sure its a match     //     return SfMatchOkay(Pattern); // *Name == '/0' }

BOOLEAN SfMatchOkay(  IN PCWSTR Pattern  ) {     //     // If pattern isn't empty, it must be a wildcard     //  while (*Pattern)  {   if (*Pattern != L'*')    return FALSE;     Pattern++;  }

//     // Matched     //     return TRUE; }

#define FAT_NTC_FCB      0x0502 #define NTFS_NTC_FCB     0x0705

BOOLEAN SfIsObjectFile(  IN PFILE_OBJECT FileObject  ) {  PFSRTL_COMMON_FCB_HEADER fcb = (PFSRTL_COMMON_FCB_HEADER) FileObject->FsContext;

KdPrint(("sfilter!SfIsObjectFile: fcb->NodeTypeCode = %x/n", fcb->NodeTypeCode));

if (fcb->NodeTypeCode == FAT_NTC_FCB)   return TRUE;  else if (fcb->NodeTypeCode == NTFS_NTC_FCB)   return TRUE;

return FALSE; }

NTSTATUS SfQuerySymbolicLink(     IN  PUNICODE_STRING SymbolicLinkName,     OUT PUNICODE_STRING LinkTarget     ) /*++

Routine Description:

This routine returns the target of the symbolic link name.

Arguments:

SymbolicLinkName    - Supplies the symbolic link name.

LinkTarget          - Returns the link target.

Return Value:

NTSTATUS

--*/

{     HANDLE Handle;     OBJECT_ATTRIBUTES ObjAttribute;     NTSTATUS Status;

InitializeObjectAttributes(&ObjAttribute, SymbolicLinkName, OBJ_CASE_INSENSITIVE,                                0, 0);

Status = ZwOpenSymbolicLinkObject(&Handle, GENERIC_READ, &ObjAttribute);     if (!NT_SUCCESS(Status))         return Status;

LinkTarget->MaximumLength = 200*sizeof(WCHAR);     LinkTarget->Length = 0;     LinkTarget->Buffer = ExAllocatePool(PagedPool, LinkTarget->MaximumLength);     if (!LinkTarget->Buffer)     {         ZwClose(Handle);         return STATUS_INSUFFICIENT_RESOURCES;     }

Status = ZwQuerySymbolicLinkObject(Handle, LinkTarget, NULL);     ZwClose(Handle);

if (!NT_SUCCESS(Status))         ExFreePool(LinkTarget->Buffer);

return Status; }

NTSTATUS SfVolumeDeviceNameToDosName(     IN PUNICODE_STRING VolumeDeviceName,     OUT PUNICODE_STRING DosName     ) /*++

Routine Description:

This routine returns a valid DOS path for the given device object.     This caller of this routine must call ExFreePool on DosName->Buffer     when it is no longer needed.

Arguments:

VolumeDeviceName    - Supplies the volume device object.

DosName             - Returns the DOS name for the volume

Return Value:

NTSTATUS

--*/

{     WCHAR Buffer[30];     UNICODE_STRING DriveLetterName;     UNICODE_STRING LinkTarget;     WCHAR Char;     NTSTATUS Status;

swprintf(Buffer, L"//??//C:");     RtlInitUnicodeString(&DriveLetterName, Buffer);

for (Char = 'A'; Char <= 'Z'; Char++)     {         DriveLetterName.Buffer[4] = Char;

Status = SfQuerySymbolicLink(&DriveLetterName, &LinkTarget);         if (!NT_SUCCESS(Status))             continue;

if (RtlEqualUnicodeString(&LinkTarget, VolumeDeviceName, TRUE))         {             ExFreePool(LinkTarget.Buffer);             break;         }

ExFreePool(LinkTarget.Buffer);     }

if (Char <= 'Z')     {         DosName->Buffer = ExAllocatePool(PagedPool, 3*sizeof(WCHAR));         if (!DosName->Buffer)             return STATUS_INSUFFICIENT_RESOURCES;

DosName->MaximumLength = 6;         DosName->Length = 4;         DosName->Buffer[0] = Char;         DosName->Buffer[1] = ':';         DosName->Buffer[2] = 0;

return STATUS_SUCCESS;     }

return STATUS_UNSUCCESSFUL; }

原文 http://blog.csdn.net/itcastcpp/article/details/4771452http://blog.csdn.net/itcastcpp/article/details/4771452