filedisk.c

功能齐全的虚拟磁盘驱动

            cdrom_toc->FirstTrack = 1;
            cdrom_toc->LastTrack = 1;
            cdrom_toc->TrackData[0].Control = TOC_DATA_TRACK;

            status = STATUS_SUCCESS;
            Irp->IoStatus.Information = sizeof(CDROM_TOC);

            break;
        }

    case IOCTL_DISK_SET_PARTITION_INFO:
        {
            if (device_extension->read_only)
            {
                status = STATUS_MEDIA_WRITE_PROTECTED;
                Irp->IoStatus.Information = 0;
                break;
            }

            if (io_stack->Parameters.DeviceIoControl.InputBufferLength <
                sizeof(SET_PARTITION_INFORMATION))
            {
                status = STATUS_INVALID_PARAMETER;
                Irp->IoStatus.Information = 0;
                break;
            }

            status = STATUS_SUCCESS;
            Irp->IoStatus.Information = 0;

            break;
        }

    case IOCTL_DISK_VERIFY:
        {
            PVERIFY_INFORMATION verify_information;

            if (io_stack->Parameters.DeviceIoControl.InputBufferLength <
                sizeof(VERIFY_INFORMATION))
            {
                status = STATUS_INVALID_PARAMETER;
                Irp->IoStatus.Information = 0;
                break;
            }

            verify_information = (PVERIFY_INFORMATION) Irp->AssociatedIrp.SystemBuffer;

            status = STATUS_SUCCESS;
            Irp->IoStatus.Information = verify_information->Length;

            break;
        }

    default:
        {
            KdPrint((
                "FileDisk: Unknown IoControlCode %#x\n",
                io_stack->Parameters.DeviceIoControl.IoControlCode
                ));

            status = STATUS_INVALID_DEVICE_REQUEST;
            Irp->IoStatus.Information = 0;
        }
    }

    if (status != STATUS_PENDING)
    {
        Irp->IoStatus.Status = status;

        IoCompleteRequest(Irp, IO_NO_INCREMENT);
    }

    return status;
}
//前面说到为每一个磁盘设备对象生成了一个系统线程，用来处理Irp
VOID
FileDiskThread (
    IN PVOID Context
    )
{
    PDEVICE_OBJECT      device_object;
    PDEVICE_EXTENSION   device_extension;
    PLIST_ENTRY         request;
    PIRP                irp;
    PIO_STACK_LOCATION  io_stack;
    PUCHAR              system_buffer;
    PUCHAR              buffer;

    ASSERT(Context != NULL);

    device_object = (PDEVICE_OBJECT) Context;

    device_extension = (PDEVICE_EXTENSION) device_object->DeviceExtension;

    KeSetPriorityThread(KeGetCurrentThread(), LOW_REALTIME_PRIORITY);

    for (;;)
    {
        KeWaitForSingleObject(
            &device_extension->request_event,
            Executive,
            KernelMode,
            FALSE,
            NULL
            );

        if (device_extension->terminate_thread)
        {
            PsTerminateSystemThread(STATUS_SUCCESS);
        }

        while (request = ExInterlockedRemoveHeadList(
            &device_extension->list_head,
            &device_extension->list_lock
            ))
        {
            irp = CONTAINING_RECORD(request, IRP, Tail.Overlay.ListEntry);

            io_stack = IoGetCurrentIrpStackLocation(irp);

            switch (io_stack->MajorFunction)
            {
            case IRP_MJ_READ:
                system_buffer = (PUCHAR) MmGetSystemAddressForMdlSafe(irp->MdlAddress, NormalPagePriority);
                if (system_buffer == NULL)
                {
                    irp->IoStatus.Status = STATUS_INSUFFICIENT_RESOURCES;
                    irp->IoStatus.Information = 0;
                    break;
                }
                buffer = (PUCHAR) ExAllocatePool(PagedPool, io_stack->Parameters.Read.Length);
                if (buffer == NULL)
                {
                    irp->IoStatus.Status = STATUS_INSUFFICIENT_RESOURCES;
                    irp->IoStatus.Information = 0;
                    break;
                }
                ZwReadFile(
                    device_extension->file_handle,
                    NULL,
                    NULL,
                    NULL,
                    &irp->IoStatus,
                    buffer,
                    io_stack->Parameters.Read.Length,
                    &io_stack->Parameters.Read.ByteOffset,
                    NULL
                    );
                RtlCopyMemory(system_buffer, buffer, io_stack->Parameters.Read.Length);
                ExFreePool(buffer);
                break;

            case IRP_MJ_WRITE:
                if ((io_stack->Parameters.Write.ByteOffset.QuadPart +
                     io_stack->Parameters.Write.Length) >
                     device_extension->file_size.QuadPart)
                {
                    irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
                    irp->IoStatus.Information = 0;
                }
                ZwWriteFile(
                    device_extension->file_handle,
                    NULL,
                    NULL,
                    NULL,
                    &irp->IoStatus,
                    MmGetSystemAddressForMdlSafe(irp->MdlAddress, NormalPagePriority),
                    io_stack->Parameters.Write.Length,
                    &io_stack->Parameters.Write.ByteOffset,
                    NULL
                    );
                break;

            case IRP_MJ_DEVICE_CONTROL:
                switch (io_stack->Parameters.DeviceIoControl.IoControlCode)
                {
                case IOCTL_FILE_DISK_OPEN_FILE:

                    SeImpersonateClient(device_extension->security_client_context, NULL);

                    irp->IoStatus.Status = FileDiskOpenFile(device_object, irp);

                    PsRevertToSelf();

                    break;

                case IOCTL_FILE_DISK_CLOSE_FILE:
                    irp->IoStatus.Status = FileDiskCloseFile(device_object, irp);
                    break;

                default:
                    irp->IoStatus.Status = STATUS_DRIVER_INTERNAL_ERROR;
                }
                break;

            default:
                irp->IoStatus.Status = STATUS_DRIVER_INTERNAL_ERROR;
            }

            IoCompleteRequest(
                irp,
                (CCHAR) (NT_SUCCESS(irp->IoStatus.Status) ?
                IO_DISK_INCREMENT : IO_NO_INCREMENT)
                );
        }
    }
}

#pragma code_seg("PAGE")

NTSTATUS
FileDiskOpenFile (
    IN PDEVICE_OBJECT   DeviceObject,
    IN PIRP             Irp
    )
{
    PDEVICE_EXTENSION               device_extension;
    POPEN_FILE_INFORMATION          open_file_information;
    UNICODE_STRING                  ufile_name;
    NTSTATUS                        status;
    OBJECT_ATTRIBUTES               object_attributes;
    FILE_END_OF_FILE_INFORMATION    file_eof;
    FILE_BASIC_INFORMATION          file_basic;
    FILE_STANDARD_INFORMATION       file_standard;
    FILE_ALIGNMENT_INFORMATION      file_alignment;

    PAGED_CODE();

    ASSERT(DeviceObject != NULL);
    ASSERT(Irp != NULL);

    device_extension = (PDEVICE_EXTENSION) DeviceObject->DeviceExtension;

    open_file_information = (POPEN_FILE_INFORMATION) Irp->AssociatedIrp.SystemBuffer;

    if (DeviceObject->DeviceType != FILE_DEVICE_CD_ROM)
    {
        device_extension->read_only = open_file_information->ReadOnly;
    }

    device_extension->file_name.Length = open_file_information->FileNameLength;
    device_extension->file_name.MaximumLength = open_file_information->FileNameLength;
    device_extension->file_name.Buffer = ExAllocatePool(NonPagedPool, open_file_information->FileNameLength);

    RtlCopyMemory(
        device_extension->file_name.Buffer,
        open_file_information->FileName,
        open_file_information->FileNameLength
        );

    status = RtlAnsiStringToUnicodeString(
        &ufile_name,
        &device_extension->file_name,
        TRUE
        );

    if (!NT_SUCCESS(status))
    {
        ExFreePool(device_extension->file_name.Buffer);
        Irp->IoStatus.Status = status;
        Irp->IoStatus.Information = 0;
        return status;
    }

    InitializeObjectAttributes(
        &object_attributes,
        &ufile_name,
        OBJ_CASE_INSENSITIVE,
        NULL,
        NULL
        );

    status = ZwCreateFile(
        &device_extension->file_handle,
        device_extension->read_only ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE,
        &object_attributes,
        &Irp->IoStatus,
        NULL,
        FILE_ATTRIBUTE_NORMAL,
        device_extension->read_only ? FILE_SHARE_READ : 0,
        FILE_OPEN,
        FILE_NON_DIRECTORY_FILE |
        FILE_RANDOM_ACCESS |
        FILE_NO_INTERMEDIATE_BUFFERING |
        FILE_SYNCHRONOUS_IO_NONALERT,
        NULL,
        0
        );

    if (status == STATUS_OBJECT_NAME_NOT_FOUND || status == STATUS_NO_SUCH_FILE)
    {
        if (device_extension->read_only || open_file_information->FileSize.QuadPart == 0)
        {
            ExFreePool(device_extension->file_name.Buffer);
            RtlFreeUnicodeString(&ufile_name);

            Irp->IoStatus.Status = STATUS_NO_SUCH_FILE;
            Irp->IoStatus.Information = 0;

            return STATUS_NO_SUCH_FILE;
        }
        else
        {
            status = ZwCreateFile(
                &device_extension->file_handle,
                GENERIC_READ | GENERIC_WRITE,
                &object_attributes,
                &Irp->IoStatus,
                &open_file_information->FileSize,
                FILE_ATTRIBUTE_NORMAL,
                0,
                FILE_OPEN_IF,
                FILE_NON_DIRECTORY_FILE |
                FILE_RANDOM_ACCESS |
                FILE_NO_INTERMEDIATE_BUFFERING |
                FILE_SYNCHRONOUS_IO_NONALERT,
                NULL,
                0
                );

            if (!NT_SUCCESS(status))
            {
                ExFreePool(device_extension->file_name.Buffer);
                RtlFreeUnicodeString(&ufile_name);
                return status;
            }

            if (Irp->IoStatus.Information == FILE_CREATED)
            {
                file_eof.EndOfFile.QuadPart = open_file_information->FileSize.QuadPart;

                status = ZwSetInformationFile(
                    device_extension->file_handle,
                    &Irp->IoStatus,
                    &file_eof,
                    sizeof(FILE_END_OF_FILE_INFORMATION),
                    FileEndOfFileInformation
                    );

                if (!NT_SUCCESS(status))
                {
                    ExFreePool(device_extension->file_name.Buffer);
                    RtlFreeUnicodeString(&ufile_name);
                    ZwClose(device_extension->file_handle);
                    return status;
                }
            }
        }
    }
    else if (!NT_SUCCESS(status))
    {
        ExFreePool(device_extension->file_name.Buffer);
        RtlFreeUnicodeString(&ufile_name);
        return status;
    }

    RtlFreeUnicodeString(&ufile_name);

    status = ZwQueryInformationFile(
        device_extension->file_handle,
        &Irp->IoStatus,
        &file_basic,
        sizeof(FILE_BASIC_INFORMATION),
        FileBasicInformation
        );

    if (!NT_SUCCESS(status))
    {
        ExFreePool(device_extension->file_name.Buffer);
        ZwClose(device_extension->file_handle);
        return status;
    }

/*
    //
    // The NT cache manager can deadlock if a filesystem that is using the cache
    // manager is used in a virtual disk that stores its file on a filesystem
    // that is also using the cache manager, this is why we open the file with
    // FILE_NO_INTERMEDIATE_BUFFERING above, however if the file is compressed
    // or encrypted NT will not honor this request and cache it anyway since it
    // need to store the decompressed/unencrypted data somewhere, therefor we put
    // an extra check here and don't alow disk images to be compressed/encrypted.
    //
    if (file_basic.FileAttributes & (FILE_ATTRIBUTE_COMPRESSED | FILE_ATTRIBUTE_ENCRYPTED))
    {
        ExFreePool(device_extension->file_name.Buffer);
        ZwClose(device_extension->file_handle);
        Irp->IoStatus.Status = STATUS_ACCESS_DENIED;
        Irp->IoStatus.Information = 0;
        return STATUS_ACCESS_DENIED;
    }
*/

    status = ZwQueryInformationFile(
        device_extension->file_handle,
        &Irp->IoStatus,
        &file_standard,
        sizeof(FILE_STANDARD_INFORMATION),
        FileStandardInformation
        );

    if (!NT_SUCCESS(status))
    {
        ExFreePool(device_extension->file_name.Buffer);
        ZwClose(device_extension->file_handle);
        return status;
    }

    device_extension->file_size.QuadPart = file_standard.EndOfFile.QuadPart;

    status = ZwQueryInformationFile(
        device_extension->file_handle,
        &Irp->IoStatus,
        &file_alignment,
        sizeof(FILE_ALIGNMENT_INFORMATION),
        FileAlignmentInformation
        );

    if (!NT_SUCCESS(status))
    {
        ExFreePool(device_extension->file_name.Buffer);
        ZwClose(device_extension->file_handle);
        return status;
    }

    DeviceObject->AlignmentRequirement = file_alignment.AlignmentRequirement;

    if (device_extension->read_only)
    {
        DeviceObject->Characteristics |= FILE_READ_ONLY_DEVICE;
    }
    else
    {
        DeviceObject->Characteristics &= ~FILE_READ_ONLY_DEVICE;
    }

    device_extension->media_in_device = TRUE;

    Irp->IoStatus.Status = STATUS_SUCCESS;
    Irp->IoStatus.Information = 0;

    return STATUS_SUCCESS;
}

NTSTATUS
FileDiskCloseFile (
    IN PDEVICE_OBJECT   DeviceObject,
    IN PIRP             Irp
    )
{
    PDEVICE_EXTENSION device_extension;

    PAGED_CODE();

    ASSERT(DeviceObject != NULL);
    ASSERT(Irp != NULL);

    device_extension = (PDEVICE_EXTENSION) DeviceObject->DeviceExtension;
//释放分配文件名内存和关闭文件句柄
    ExFreePool(device_extension->file_name.Buffer);

    ZwClose(device_extension->file_handle);
    device_extension->media_in_device = FALSE;

//经常这两个在一起
    Irp->IoStatus.Status = STATUS_SUCCESS;
    Irp->IoStatus.Information = 0;

    return STATUS_SUCCESS;
}