驱动入口函数DriverEntry

DriverEntry是Windows内核驱动的入口函数，其函数原型如下：

NTSTATUS DriverEntry(__in PDRIVER_OBJECT drvobj, __in PUNICODE_STRING RegistryPath);

其包括两个参数，一个为该驱动的对象结构体指针，另一个是该驱动服务的注册表字符串路径。
在DriverEntry中，一个最基本的功能是需要初始化PDRIVER_OBJECT drvobj的各种回调函数指针。

typedef struct _DRIVER_OBJECT {
    CSHORT Type;
    CSHORT Size;

    //
    // The following links all of the devices created by a single driver
    // together on a list, and the Flags word provides an extensible flag
    // location for driver objects.
    //

    PDEVICE_OBJECT DeviceObject;
    ULONG Flags;

    //
    // The following section describes where the driver is loaded.  The count
    // field is used to count the number of times the driver has had its
    // registered reinitialization routine invoked.
    //

    PVOID DriverStart;
    ULONG DriverSize;
    PVOID DriverSection;
    PDRIVER_EXTENSION DriverExtension;

    //
    // The driver name field is used by the error log thread
    // determine the name of the driver that an I/O request is/was bound.
    //

    UNICODE_STRING DriverName;

    //
    // The following section is for registry support.  This is a pointer
    // to the path to the hardware information in the registry
    //

    PUNICODE_STRING HardwareDatabase;

    //
    // The following section contains the optional pointer to an array of
    // alternate entry points to a driver for "fast I/O" support.  Fast I/O
    // is performed by invoking the driver routine directly with separate
    // parameters, rather than using the standard IRP call mechanism.  Note
    // that these functions may only be used for synchronous I/O, and when
    // the file is cached.
    //

    PFAST_IO_DISPATCH FastIoDispatch;

    //
    // The following section describes the entry points to this particular
    // driver.  Note that the major function dispatch table must be the last
    // field in the object so that it remains extensible.
    //

    PDRIVER_INITIALIZE DriverInit;
    PDRIVER_STARTIO DriverStartIo;
    PDRIVER_UNLOAD DriverUnload;
    PDRIVER_DISPATCH MajorFunction[IRP_MJ_MAXIMUM_FUNCTION + 1];

} DRIVER_OBJECT;
typedef struct _DRIVER_OBJECT *PDRIVER_OBJECT;

如我们这里以USBIP的函数为例，在DriverEntry中中断下来，看一下该结构体的成员信息。

 kd> dt _DRIVER_OBJECT 0xffffbc88`3db017d0
usbip_vhci!_DRIVER_OBJECT
   +0x000 Type             : 0n4
   +0x002 Size             : 0n336
   +0x008 DeviceObject     : (null) 
   +0x010 Flags            : 2
   +0x018 DriverStart      : 0xfffff807`b5c30000 Void
   +0x020 DriverSize       : 0x1f000
   +0x028 DriverSection    : 0xffffbc88`3d0afb40 Void
   +0x030 DriverExtension  : 0xffffbc88`3db01920 _DRIVER_EXTENSION
   +0x038 DriverName       : _UNICODE_STRING "\Driver\usbip_vhci"
   +0x048 HardwareDatabase : 0xfffff803`655c2eb8 _UNICODE_STRING "\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\SYSTEM"
   +0x050 FastIoDispatch   : (null) 
   +0x058 DriverInit       : 0xfffff807`b5c38050     long  usbip_vhci!FxDriverEntry+0
   +0x060 DriverStartIo    : (null) 
   +0x068 DriverUnload     : (null) 
   +0x070 MajorFunction    : [28] 0xfffff803`64ebf6b4     long  nt!KeInsertQueue+0

2: kd> dt _DRIVER_EXTENSION 0xffffbc88`3db01920 
usbip_vhci!_DRIVER_EXTENSION
   +0x000 DriverObject     : 0xffffbc88`3db017d0 _DRIVER_OBJECT
   +0x008 AddDevice        : (null) 
   +0x010 Count            : 0
   +0x018 ServiceKeyName   : _UNICODE_STRING "usbip_vhci"

而其注册表信息PUNICODE_STRING RegistryPath内容如：

\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\usbip_vhci