nt4/LoadUnload.c

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/*
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 *  Copyright 2004 Spiro Trikaliotis
 *
 */

#include <ntddk.h>
#include "cbm_driver.h"
#include "cbmioctl.h"

#undef ExFreePool

NTSTATUS
AddDevice(IN PDRIVER_OBJECT DriverObject, IN PDEVICE_OBJECT PdoUNUSED, IN PCWSTR ParallelPortName)
{
    PDEVICE_OBJECT fdo;
    UNICODE_STRING deviceNameNumber;
    UNICODE_STRING deviceNamePrefix;
    UNICODE_STRING deviceName;
    NTSTATUS ntStatus;
    WCHAR deviceNameNumberBuffer[50];

    static SHORT no = 0;

    FUNC_ENTER();

    UNREFERENCED_PARAMETER(PdoUNUSED);

    // Until now, no error has occurred

    ntStatus = STATUS_SUCCESS;

    // Create the name for the fdo
    // thus, this is a named driver

    DBG_IRQL( <= DISPATCH_LEVEL);
    RtlInitUnicodeString(&deviceNamePrefix, CBMDEVICENAME);

    // Convert variable no into a UNICODE_STRING

    deviceNameNumber.Length = 0;
    deviceNameNumber.MaximumLength = sizeof(deviceNameNumberBuffer);
    deviceNameNumber.Buffer = deviceNameNumberBuffer;
    DBG_IRQL( == PASSIVE_LEVEL);
    RtlIntegerToUnicodeString(no, 10, &deviceNameNumber);

    // Increment the number for the next device

    ++no;

    // Allocate enough space for the concatenation of deviceNamePrefix
    // and deviceNameNumber

    deviceName.MaximumLength = deviceNamePrefix.Length + deviceNameNumber.Length;
    deviceName.Buffer = (PWCHAR) ExAllocatePoolWithTag(NonPagedPool, 
        deviceName.MaximumLength, MTAG_DEVNAME);

    if (!deviceName.Buffer)
    {
        ntStatus = STATUS_INSUFFICIENT_RESOURCES;
        DBG_ERROR((DBG_PREFIX "Could not allocate memory for deviceName"))
        LogErrorString(NULL, CBM_START_FAILED, L"allocating memory for device name", NULL);
    }

    if (NT_SUCCESS(ntStatus))
    {
        // Concatenate both strings

        DBG_IRQL( < DISPATCH_LEVEL);
        RtlCopyUnicodeString(&deviceName, &deviceNamePrefix);
        DBG_IRQL( < DISPATCH_LEVEL);
        RtlAppendUnicodeStringToString(&deviceName, &deviceNameNumber);

        // create the FDO with the name just build

        DBG_IRQL( == PASSIVE_LEVEL);
        ntStatus = IoCreateDevice(DriverObject, sizeof(DEVICE_EXTENSION), &deviceName,
            FILE_DEVICE_UNKNOWN, FILE_DEVICE_SECURE_OPEN, TRUE, &fdo);

        if (!NT_SUCCESS(ntStatus))
        {
            DBG_ERROR((DBG_PREFIX "IoCreateDevice failed with 0x%08X - %s",
                ntStatus, DebugNtStatus(ntStatus)));
            LogErrorString(NULL, CBM_START_FAILED, L"creation of the device object", NULL);
        }
    }

    if (NT_SUCCESS(ntStatus))
    {
        PDEVICE_EXTENSION pdx;

        // Initialization common to WDM and NT4 driver

        ntStatus = AddDeviceCommonInit(fdo, &deviceName, ParallelPortName);

        // mark that we are running the NT4 version of the driver

        pdx = fdo->DeviceExtension;
        pdx->IsNT4 = TRUE;

        if (!NT_SUCCESS(ntStatus))
        {
            // An error has occurred, thus, delete the device

            // If necessary, delete the buffer for the device name

            if (pdx->DeviceName.Buffer)
            {
                DBG_IRQL( < DISPATCH_LEVEL);
                ExFreePool(pdx->DeviceName.Buffer);
            }

            DBG_IRQL( == PASSIVE_LEVEL);
            IoDeleteDevice(fdo);
        }
    }

    FUNC_LEAVE_NTSTATUS(ntStatus);
}

static KMUTEX MutexDriverLoadUnload;

VOID
DriverUnload(IN PDRIVER_OBJECT DriverObject)
{
    PDEVICE_OBJECT currentDevice;

    FUNC_ENTER();

    // Obtain the mutex that prevents premature unloading

    DBG_IRQL( < DISPATCH_LEVEL);
    KeWaitForMutexObject(&MutexDriverLoadUnload, Executive, KernelMode,
        FALSE, NULL);

    // Make sure every device object is deleted

    while (currentDevice = DriverObject->DeviceObject) 
    {
        PDEVICE_EXTENSION pdx = currentDevice->DeviceExtension;

        DBG_ASSERT(pdx);

        // Unlock the parallel port, if necessary

        if (pdx->ParallelPortIsLocked)
        {
            cbm_unlock_parport(pdx);
        }

        // Stop the thread of that device, if necessary

        cbm_stop_thread(pdx);

        // Uninitialize the parallel port, if necessary

        ParPortDeinit(pdx);

        // If a buffer for the device name has been allocated,
        // release that

        if (pdx->DeviceName.Buffer)
        {
            DBG_IRQL( < DISPATCH_LEVEL);
            ExFreePool(pdx->DeviceName.Buffer);
        }

        // Delete the device
        // This has to be done *after* the above, as the pdx
        // is not allowed to be accessed anymore here.

        DBG_IRQL( == PASSIVE_LEVEL);
        IoDeleteDevice(currentDevice);
    }

    // some more uninitialization, common to WDM and NT4 driver

    DriverCommonUninit();

#if DBG

    DbgFreeMemoryBuffer();

#endif

    // From now on, it is legal to be unloaded

    DBG_IRQL( <= DISPATCH_LEVEL);
    KeReleaseMutex(&MutexDriverLoadUnload, FALSE);

    FUNC_LEAVE();
}

NTSTATUS
DriverEntry(IN PDRIVER_OBJECT DriverObject, IN PUNICODE_STRING RegistryPath)
{
    PENUMERATE enumerate;
    NTSTATUS ntStatus;

    FUNC_ENTER();

    // Initialize the debugging system

    DBG_INIT();

    // Initialize the mutex which should prevent premature unloading

    KeInitializeMutex(&MutexDriverLoadUnload, 0);

    // Now, obtain that mutex as first operation

    DBG_IRQL( < DISPATCH_LEVEL);
    KeWaitForMutexObject(&MutexDriverLoadUnload, Executive, KernelMode,
        FALSE, NULL);

#if DBG

    DbgAllocateMemoryBuffer();

#endif

    // Output a status message

    DBG_PRINT((DBG_PREFIX "CBM4NT.SYS " __DATE__ " " __TIME__));

    // Perform initialization common to NT4 and WDM driver

    ntStatus = DriverCommonInit(DriverObject, RegistryPath);

    // enumerate all parallel port drivers:

    ntStatus = ParPortEnumerateOpen(&enumerate);

    if (NT_SUCCESS(ntStatus))
    {
        PCWSTR DriverName;

        do 
        {
            ntStatus = ParPortEnumerate(enumerate,&DriverName);

            if (NT_SUCCESS(ntStatus) && *DriverName)
            {
                DBG_SUCCESS((DBG_PREFIX "Drivername = \"%ws\"", DriverName));
                AddDevice(DriverObject, NULL, DriverName);
            }
        } while (NT_SUCCESS(ntStatus) && *DriverName);

        ParPortEnumerateClose(enumerate);
    }

    // From now on, it is legal to be unloaded

    DBG_IRQL( <= DISPATCH_LEVEL);
    KeReleaseMutex(&MutexDriverLoadUnload, FALSE);

    FUNC_LEAVE_NTSTATUS_CONST(STATUS_SUCCESS);
}