reactos操作系统实现(118)

ScsiClassInitialize函数初始化驱动程序对象，主要是找到合适的端口驱动程序，并设置它来处理磁盘的命令，具体实现代码如下：

#001 ULONG

#002 NTAPI

#003 ScsiClassInitialize(

#004 IN PVOID Argument1,

#005 IN PVOID Argument2,

#006 IN PCLASS_INIT_DATA InitializationData

#007 )

#008

#009 /*++

#010

#011 Routine Description:

#012

#013 This routine is called by a class driver during its

#014 DriverEntry routine to initialize the driver.

#015

#016 Arguments:

#017

#018 Argument1 - Driver Object.

#019 Argument2 - Registry Path.

#020 InitializationData - Device-specific driver's initialization data.

#021

#022 Return Value:

#023

#024 A valid return code for a DriverEntry routine.

#025

#026 --*/

#027

#028 {

#029

#030

驱动程序对象。

#031 PDRIVER_OBJECT DriverObject = Argument1;

#032 ULONG portNumber = 0;

#033 PDEVICE_OBJECT portDeviceObject;

#034 NTSTATUS status;

#035 STRING deviceNameString;

#036 UNICODE_STRING unicodeDeviceName;

#037 PFILE_OBJECT fileObject;

#038 CCHAR deviceNameBuffer[256];

#039 BOOLEAN deviceFound = FALSE;

#040

#041 DebugPrint((3,"/n/nSCSI Class Driver/n"));

#042

#043 //

#044 // Validate the length of this structure. This is effectively a

#045 // version check.

#046 //

#047

判断初始化的数据结构大小是否与函数处理的一样，如果不一样版本就返回出错。

#048 if (InitializationData->InitializationDataSize > sizeof(CLASS_INIT_DATA)) {

#049

#050 DebugPrint((0,"ScsiClassInitialize: Class driver wrong version/n"));

#051 return (ULONG) STATUS_REVISION_MISMATCH;

#052 }

#053

#054 //

#055 // Check that each required entry is not NULL. Note that Shutdown,Flush and Error

#056 // are not required entry points.

#057 //

#058

判断初始化的函数是否正确设置了。

#059 if ((!InitializationData->ClassFindDevices) ||

#060 (!InitializationData->ClassDeviceControl) ||

#061 (!((InitializationData->ClassReadWriteVerification) ||

#062 (InitializationData->ClassStartIo)))) {

#063

#064 DebugPrint((0,

#065 "ScsiClassInitialize: Class device-specific driver missing required entry/n"));

#066

#067 return (ULONG) STATUS_REVISION_MISMATCH;

#068 }

#069

#070 //

#071 // Update driver object with entry points.

#072 //

#073

设置驱动程序功能调用的函数。

#074 DriverObject->MajorFunction[IRP_MJ_CREATE] = ScsiClassCreateClose;

#075 DriverObject->MajorFunction[IRP_MJ_CLOSE] = ScsiClassCreateClose;

#076 DriverObject->MajorFunction[IRP_MJ_READ] = ScsiClassReadWrite;

#077 DriverObject->MajorFunction[IRP_MJ_WRITE] = ScsiClassReadWrite;

#078 DriverObject->MajorFunction[IRP_MJ_SCSI] = ScsiClassInternalIoControl;

#079 DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = ScsiClassDeviceControlDispatch;

#080 DriverObject->MajorFunction[IRP_MJ_SHUTDOWN] = ScsiClassShutdownFlush;

#081 DriverObject->MajorFunction[IRP_MJ_FLUSH_BUFFERS] = ScsiClassShutdownFlush;

#082

如果StartIO函数，就需要设置顺序操作IO函数。

#083 if (InitializationData->ClassStartIo) {

#084 DriverObject->DriverStartIo = InitializationData->ClassStartIo;

#085 }

#086

#087 //

#088 // Open port driver controller device objects by name.

#089 //

#090

通设备名称来打开端口设备驱动对象。

#091 do {

#092

#093 sprintf(deviceNameBuffer,"//Device//ScsiPort%lu",portNumber);

#094

#095 DebugPrint((2,"ScsiClassInitialize: Open Port %s/n",deviceNameBuffer));

#096

#097 RtlInitString(&deviceNameString,deviceNameBuffer);

#098

#099 status = RtlAnsiStringToUnicodeString(&unicodeDeviceName,

#100 &deviceNameString,

#101 TRUE);

#102

#103 if (!NT_SUCCESS(status)){

#104 break;

#105 }

#106

通过设备名称来获取端口驱动程序。

#107 status = IoGetDeviceObjectPointer(&unicodeDeviceName,

#108 FILE_READ_ATTRIBUTES,

#109 &fileObject,

#110 &portDeviceObject);

#111

#112 if (NT_SUCCESS(status)) {

#113

#114 //

#115 // Call the device-specific driver's FindDevice routine.

#116 //

#117

查找这个设备是否匹配。

#118 if (InitializationData->ClassFindDevices(DriverObject,Argument2,InitializationData,

#119 portDeviceObject,portNumber)) {

#120

如果找到设备就设置返回成功标志。

#121 deviceFound = TRUE;

#122 }

#123 }

#124

#125 //

#126 // Check next SCSI adapter.

#127 //

#128

#129 portNumber++;

#130

#131 } while(NT_SUCCESS(status));

#132

#133 return deviceFound ? STATUS_SUCCESS : STATUS_NO_SUCH_DEVICE;

#134}

（编辑：李大同）

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