Logging.c File Reference

Message logging and tracing implementation. More...

#include "pch.h"

Functions
BOOLEAN	LogCheckVmxOperation ()
	Checks whether the message tracing operates on vmx-root mode or not.
BOOLEAN	LogCheckImmediateSend (UINT32 OperationCode)
	Checks whether the immediate sending is needed or not.
BOOLEAN	LogSendImmediateMessage (CHAR *OptionalBuffer, UINT32 OptionalBufferLength, UINT32 OperationCode)
	Checks whether the immediate sending is needed or not.
BOOLEAN	LogInitialize (MESSAGE_TRACING_CALLBACKS *MsgTracingCallbacks)
	Initialize the buffer relating to log message tracing.
VOID	LogUnInitialize ()
	Uninitialize the buffer relating to log message tracing.
BOOLEAN	LogCallbackCheckIfBufferIsFull (BOOLEAN Priority)
	Checks whether the priority or regular buffer is full or not.
_Use_decl_annotations_ BOOLEAN	LogCallbackSendBuffer (UINT32 OperationCode, PVOID Buffer, UINT32 BufferLength, BOOLEAN Priority)
	Save buffer to the pool.
UINT32	LogMarkAllAsRead (BOOLEAN IsVmxRoot)
	Mark all buffers as read.
BOOLEAN	LogReadBuffer (BOOLEAN IsVmxRoot, PVOID BufferToSaveMessage, UINT32 *ReturnedLength)
	Attempt to read the buffer.
BOOLEAN	LogCheckForNewMessage (BOOLEAN IsVmxRoot, BOOLEAN Priority)
	Check if new message is available or not.
BOOLEAN	LogCallbackPrepareAndSendMessageToQueueWrapper (UINT32 OperationCode, BOOLEAN IsImmediateMessage, BOOLEAN ShowCurrentSystemTime, BOOLEAN Priority, const CHAR *Fmt, va_list ArgList)
	Prepare a printf-style message mapping and send string messages and tracing for logging and monitoring.
BOOLEAN	LogCallbackPrepareAndSendMessageToQueue (UINT32 OperationCode, BOOLEAN IsImmediateMessage, BOOLEAN ShowCurrentSystemTime, BOOLEAN Priority, const CHAR *Fmt,...)
	Prepare a printf-style message mapping and send string messages and tracing for logging and monitoring.
BOOLEAN	LogCallbackSendMessageToQueue (UINT32 OperationCode, BOOLEAN IsImmediateMessage, CHAR *LogMessage, UINT32 BufferLen, BOOLEAN Priority)
	Send string messages and tracing for logging and monitoring.
VOID	LogNotifyUsermodeCallback (PKDPC Dpc, PVOID DeferredContext, PVOID SystemArgument1, PVOID SystemArgument2)
	Complete the IRP in IRP Pending state and fill the usermode buffers with pool data.
BOOLEAN	LogRegisterIrpBasedNotification (PVOID TargetIrp, LONG *Status)
	Register a new IRP Pending thread which listens for new buffers.
BOOLEAN	LogRegisterEventBasedNotification (PVOID TargetIrp)
	Create an event-based usermode notifying mechanism.

Detailed Description

Message logging and tracing implementation.

Author

Sina Karvandi (sina@.nosp@m.hype.nosp@m.rdbg..nosp@m.org)

Version

0.1

Date

2020-04-11

Copyright

This project is released under the GNU Public License v3.

Function Documentation

LogCallbackCheckIfBufferIsFull()

BOOLEAN LogCallbackCheckIfBufferIsFull

(

BOOLEAN

Priority

)

Checks whether the priority or regular buffer is full or not.

Parameters

Priority

Whether the buffer has priority

Returns

BOOLEAN Returns true if the buffer is full, otherwise, return false

{
    UINT32  Index;
    BOOLEAN IsVmxRoot;
    UINT32  CurrentIndexToWrite         = NULL_ZERO;
    UINT32  CurrentIndexToWritePriority = NULL_ZERO;
 
    //
    // Check that if we're in vmx root-mode
    //
    IsVmxRoot = LogCheckVmxOperation();
 
    if (IsVmxRoot)
    {
        //
        // Set the index
        //
        Index = 1;
    }
    else
    {
        //
        // Set the index
        //
        Index = 0;
    }
 
    //
    // check if the buffer is filled to it's maximum index or not
    //
    if (Priority)
    {
        CurrentIndexToWritePriority = g_MessageBufferInformation[Index].CurrentIndexToWritePriority;
 
        if (g_MessageBufferInformation[Index].CurrentIndexToWritePriority > MaximumPacketsCapacityPriority - 1)
        {
            //
            // start from the beginning
            //
            CurrentIndexToWritePriority = 0;
        }
    }
    else
    {
        CurrentIndexToWrite = g_MessageBufferInformation[Index].CurrentIndexToWrite;
 
        if (g_MessageBufferInformation[Index].CurrentIndexToWrite > MaximumPacketsCapacity - 1)
        {
            //
            // start from the beginning
            //
            CurrentIndexToWrite = 0;
        }
    }
 
    //
    // Compute the start of the buffer header
    //
    BUFFER_HEADER * Header;
 
    if (Priority)
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (CurrentIndexToWritePriority * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
    else
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (CurrentIndexToWrite * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
 
    //
    // If the next item is valid, then it means the buffer is full and the next
    // item will replace the previous (not served items)
    //
    return Header->Valid;
}

LogCallbackPrepareAndSendMessageToQueue()

BOOLEAN LogCallbackPrepareAndSendMessageToQueue	(	UINT32	OperationCode,
		BOOLEAN	IsImmediateMessage,
		BOOLEAN	ShowCurrentSystemTime,
		BOOLEAN	Priority,
		const CHAR *	Fmt,
			... )

Prepare a printf-style message mapping and send string messages and tracing for logging and monitoring.

Parameters

OperationCode	Optional operation code
IsImmediateMessage	Should be sent immediately
ShowCurrentSystemTime	Show system-time
Priority	Whether the message has priority
Fmt	Message format-string
...

Returns

BOOLEAN if it was successful then return TRUE, otherwise returns FALSE

{
    va_list ArgList;
    BOOLEAN Result;
 
    va_start(ArgList, Fmt);
 
    Result = LogCallbackPrepareAndSendMessageToQueueWrapper(OperationCode,
                                                            IsImmediateMessage,
                                                            ShowCurrentSystemTime,
                                                            Priority,
                                                            Fmt,
                                                            ArgList);
 
    va_end(ArgList);
 
    return Result;
}

LogCallbackPrepareAndSendMessageToQueueWrapper()

BOOLEAN LogCallbackPrepareAndSendMessageToQueueWrapper	(	UINT32	OperationCode,
		BOOLEAN	IsImmediateMessage,
		BOOLEAN	ShowCurrentSystemTime,
		BOOLEAN	Priority,
		const CHAR *	Fmt,
		va_list	ArgList )

Prepare a printf-style message mapping and send string messages and tracing for logging and monitoring.

Parameters

OperationCode	Optional operation code
IsImmediateMessage	Should be sent immediately
ShowCurrentSystemTime	Show system-time
Priority	Whether the message has priority
Fmt	Message format-string
...

Returns

BOOLEAN if it was successful then return TRUE, otherwise returns FALSE

{
    INT32   SprintfResult;
    SIZE_T  WrittenSize;
    BOOLEAN IsVmxRootMode;
    BOOLEAN Result         = FALSE; // by default, we assume error happens
    CHAR *  LogMessage     = NULL;
    CHAR *  TempMessage    = NULL;
    CHAR    TimeBuffer[20] = {0};
    ULONG   CurrentCore    = PlatformCpuGetCurrentProcessorNumber();
 
    //
    // Set Vmx State
    //
    IsVmxRootMode = LogCheckVmxOperation();
 
    //
    // Set the buffer here, we avoid use stack (local variables) because stack might growth
    // and be problematic
    //
    if (IsVmxRootMode)
    {
        LogMessage  = &g_VmxLogMessage[CurrentCore * PacketChunkSize];
        TempMessage = &g_VmxTempMessage[CurrentCore * PacketChunkSize];
    }
    else
    {
        //
        // To avoid buffer collision and buffer re-writing in VMX non-root, allocate pool
        //
        LogMessage = PlatformMemAllocateNonPagedPool(PacketChunkSize);
 
        if (LogMessage == NULL)
        {
            //
            // Insufficient space
            //
            return FALSE;
        }
        TempMessage = PlatformMemAllocateNonPagedPool(PacketChunkSize);
 
        if (TempMessage == NULL)
        {
            //
            // Insufficient space
            //
            PlatformMemFreePool(LogMessage);
            return FALSE;
        }
    }
 
    if (ShowCurrentSystemTime)
    {
        //
        // It's actually not necessary to use -1 but because user-mode code might assume a null-terminated buffer so
        // it's better to use - 1
        //
 
        //
        // We won't use this because we can't use in any IRQL
        // Status = RtlStringCchVPrintfA(TempMessage, PacketChunkSize - 1, Fmt, ArgList);
        //
        SprintfResult = vsprintf_s(TempMessage, PacketChunkSize - 1, Fmt, ArgList);
 
        //
        // Check if the buffer passed the limit
        //
        if (SprintfResult == -1)
        {
            //
            // Probably the buffer is large that we can't store it
            //
            goto FreeBufferAndReturn;
        }
 
        //
        // Fill the above with timer
        //
        TIME_FIELDS   TimeFields;
        LARGE_INTEGER SystemTime, LocalTime;
        PlatformTimeQuerySystemTime(&SystemTime);
        PlatformTimeConvertToLocalTime(&SystemTime, &LocalTime);
        PlatformTimeConvertToTimeFields(&LocalTime, &TimeFields);
 
        //
        // We won't use this because we can't use in any IRQL
        // Status = RtlStringCchPrintfA(TimeBuffer, RTL_NUMBER_OF(TimeBuffer),
        //  "%02hd:%02hd:%02hd.%03hd", TimeFields.Hour,
        //  TimeFields.Minute, TimeFields.Second,
        //  TimeFields.Milliseconds);
        //
        //
        // Append time with previous message
        //
        // Status = RtlStringCchPrintfA(LogMessage, PacketChunkSize - 1, "(%s)\t %s", TimeBuffer, TempMessage);
        //
 
        //
        // this function probably run without error, so there is no need to check the return value
        //
        sprintf_s(TimeBuffer, RTL_NUMBER_OF(TimeBuffer), "%02hd:%02hd:%02hd.%03hd", TimeFields.Hour, TimeFields.Minute, TimeFields.Second, TimeFields.Milliseconds);
 
        //
        // Append time with previous message
        //
        SprintfResult = sprintf_s(LogMessage, PacketChunkSize - 1, "(%s - core : %d - vmx-root? %s)\t %s", TimeBuffer, CurrentCore, IsVmxRootMode ? "yes" : "no", TempMessage);
 
        //
        // Check if the buffer passed the limit
        //
        if (SprintfResult == -1)
        {
            //
            // Probably the buffer is large that we can't store it
            //
            goto FreeBufferAndReturn;
        }
    }
    else
    {
        //
        // It's actually not necessary to use -1 but because user-mode code might assume a null-terminated buffer so
        // it's better to use - 1
        //
 
        //
        // We won't use this because we can't use in any IRQL
        // Status = RtlStringCchVPrintfA(LogMessage, PacketChunkSize - 1, Fmt, ArgList);
        //
        SprintfResult = vsprintf_s(LogMessage, PacketChunkSize - 1, Fmt, ArgList);
 
        //
        // Check if the buffer passed the limit
        //
        if (SprintfResult == -1)
        {
            //
            // Probably the buffer is large that we can't store it
            //
            goto FreeBufferAndReturn;
        }
    }
 
    //
    // Use std function because they can be run in any IRQL
    // RtlStringCchLengthA(LogMessage, PacketChunkSize - 1, &WrittenSize);
    //
    WrittenSize = strnlen_s(LogMessage, PacketChunkSize - 1);
 
    if (LogMessage[0] == '\0')
    {
        //
        // nothing to write
        //
        goto FreeBufferAndReturn;
    }
 
    //
    // Send the prepared buffer (with no priority)
    //
    Result = LogCallbackSendMessageToQueue(OperationCode, IsImmediateMessage, LogMessage, (UINT32)WrittenSize, Priority);
 
FreeBufferAndReturn:
 
    if (!IsVmxRootMode)
    {
        PlatformMemFreePool(LogMessage);
        PlatformMemFreePool(TempMessage);
    }
 
    return Result;
}

LogCallbackSendBuffer()

_Use_decl_annotations_ BOOLEAN LogCallbackSendBuffer	(	UINT32	OperationCode,
		PVOID	Buffer,
		UINT32	BufferLength,
		BOOLEAN	Priority )

Save buffer to the pool.

Parameters

OperationCode	The operation code that will be send to user mode
Buffer	Buffer to be send to user mode
BufferLength	Length of the buffer
Priority	Whether the buffer has priority

Returns

BOOLEAN Returns true if the buffer successfully set to be send to user mode and false if there was an error

{
    UINT32  Index;
    BOOLEAN IsVmxRoot;
    KIRQL   OldIRQL = NULL_ZERO;
 
    if (BufferLength > PacketChunkSize - 1 || BufferLength == 0)
    {
        //
        // We can't save this huge buffer
        //
        return FALSE;
    }
 
    //
    // Check that if we're in vmx root-mode
    //
    IsVmxRoot = LogCheckVmxOperation();
 
    //
    // Check if we're connected to remote debugger, send it directly to the debugger
    // and the OPERATION_MANDATORY_DEBUGGEE_BIT should not be set because those operation
    // codes that their MSB are set should be handled locally
    //
    if (LogCheckImmediateSend(OperationCode))
    {
        //
        // if we're in vmx non-root then in order to avoid scheduling we raise the IRQL
        // to DISPATCH_LEVEL because we will get the lock of sending over serial in the
        // next function. In vmx-root RFLAGS.IF is cleared so no interrupt happens and
        // we're safe to get the lock, the same approach is for KeAcquireSpinLock
        //
        if (!IsVmxRoot)
        {
            //
            // vmx non-root
            //
            OldIRQL = PlatformIrqlRaiseToDpcLevel();
        }
 
        //
        // Kernel debugger is active, we should send the bytes over serial
        //
        LogSendImmediateMessage(
            Buffer,
            BufferLength,
            OperationCode);
 
        //
        // Release the vmx non-root lock
        //
        if (!IsVmxRoot)
        {
            //
            // vmx non-root
            //
            PlatformIrqlLower(OldIRQL);
        }
 
        return TRUE;
    }
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        //
        // Set the index
        //
        Index = 1;
        SpinlockLock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Set the index
        //
        Index = 0;
 
        //
        // Acquire the lock
        //
        PlatformSpinlockAcquire(&g_MessageBufferInformation[Index].BufferLock, &OldIRQL);
    }
 
    //
    // check if the buffer is filled to it's maximum index or not
    //
    if (Priority)
    {
        if (g_MessageBufferInformation[Index].CurrentIndexToWritePriority > MaximumPacketsCapacityPriority - 1)
        {
            //
            // start from the beginning
            //
            g_MessageBufferInformation[Index].CurrentIndexToWritePriority = 0;
        }
    }
    else
    {
        if (g_MessageBufferInformation[Index].CurrentIndexToWrite > MaximumPacketsCapacity - 1)
        {
            //
            // start from the beginning
            //
            g_MessageBufferInformation[Index].CurrentIndexToWrite = 0;
        }
    }
 
    //
    // Compute the start of the buffer header
    //
    BUFFER_HEADER * Header;
 
    if (Priority)
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (g_MessageBufferInformation[Index].CurrentIndexToWritePriority * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
    else
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToWrite * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
 
    //
    // Set the header
    //
    Header->OperationNumber = OperationCode;
    Header->BufferLength    = BufferLength;
    Header->Valid           = TRUE;
 
    //
    // ******** Now it's time to fill the buffer ********
    //
 
    //
    // compute the saving index
    //
    PVOID SavingBuffer;
 
    if (Priority)
    {
        SavingBuffer = (PVOID)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (g_MessageBufferInformation[Index].CurrentIndexToWritePriority * (PacketChunkSize + sizeof(BUFFER_HEADER))) + sizeof(BUFFER_HEADER));
    }
    else
    {
        SavingBuffer = (PVOID)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToWrite * (PacketChunkSize + sizeof(BUFFER_HEADER))) + sizeof(BUFFER_HEADER));
    }
 
    //
    // Copy the buffer
    //
    PlatformWriteMemory(SavingBuffer, Buffer, BufferLength);
 
    //
    // Increment the next index to write
    //
    if (Priority)
    {
        g_MessageBufferInformation[Index].CurrentIndexToWritePriority = g_MessageBufferInformation[Index].CurrentIndexToWritePriority + 1;
    }
    else
    {
        g_MessageBufferInformation[Index].CurrentIndexToWrite = g_MessageBufferInformation[Index].CurrentIndexToWrite + 1;
    }
 
    //
    // check if there is any thread in IRP Pending state, so we can complete their request
    //
    if (g_GlobalNotifyRecord != NULL)
    {
        //
        // there is some threads that needs to be completed
        //
 
        //
        // set the target pool
        //
        g_GlobalNotifyRecord->CheckVmxRootMessagePool = IsVmxRoot;
 
        //
        // Insert dpc to queue
        //
        PlatformDpcInsertQueueDpc(&g_GlobalNotifyRecord->Dpc, g_GlobalNotifyRecord, NULL);
 
        //
        // set notify routine to null
        //
        g_GlobalNotifyRecord = NULL;
    }
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        SpinlockUnlock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Release the lock
        //
        PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLock, OldIRQL);
    }
 
    return TRUE;
}

LogCallbackSendMessageToQueue()

BOOLEAN LogCallbackSendMessageToQueue	(	UINT32	OperationCode,
		BOOLEAN	IsImmediateMessage,
		CHAR *	LogMessage,
		UINT32	BufferLen,
		BOOLEAN	Priority )

Send string messages and tracing for logging and monitoring.

Parameters

OperationCode	Optional operation code
IsImmediateMessage	Should be sent immediately
LogMessage	Link of message buffer
BufferLen	Length of buffer
Priority	Whether the buffer has priority

Returns

BOOLEAN if it was successful then return TRUE, otherwise returns FALSE

{
    BOOLEAN Result;
    UINT32  Index;
    BOOLEAN IsVmxRootMode;
    KIRQL   OldIRQL = NULL_ZERO;
 
    //
    // Set Vmx State
    //
    IsVmxRootMode = LogCheckVmxOperation();
 
#if UseWPPTracing
 
    if (OperationCode == OPERATION_LOG_INFO_MESSAGE)
    {
        HypervisorTraceLevelMessage(
            TRACE_LEVEL_INFORMATION, // ETW Level defined in evntrace.h
            HVFS_LOG_INFO,
            "%s", // Flag defined in WPP_CONTROL_GUIDS
            LogMessage);
    }
    else if (OperationCode == OPERATION_LOG_WARNING_MESSAGE)
    {
        HypervisorTraceLevelMessage(
            TRACE_LEVEL_WARNING, // ETW Level defined in evntrace.h
            HVFS_LOG_WARNING,
            "%s", // Flag defined in WPP_CONTROL_GUIDS
            LogMessage);
    }
    else if (OperationCode == OPERATION_LOG_ERROR_MESSAGE)
    {
        HypervisorTraceLevelMessage(
            TRACE_LEVEL_ERROR, // ETW Level defined in evntrace.h
            HVFS_LOG_ERROR,
            "%s", // Flag defined in WPP_CONTROL_GUIDS
            LogMessage);
    }
    else
    {
        HypervisorTraceLevelMessage(
            TRACE_LEVEL_NONE, // ETW Level defined in evntrace.h
            HVFS_LOG,
            "%s", // Flag defined in WPP_CONTROL_GUIDS
            LogMessage);
    }
 
#else
    if (IsImmediateMessage)
    {
        return LogCallbackSendBuffer(OperationCode, LogMessage, BufferLen, Priority);
    }
    else
    {
        //
        // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
        // if not we use the windows spinlock
        //
        if (IsVmxRootMode)
        {
            //
            // Set the index
            //
            Index = 1;
            SpinlockLock(&g_VmxRootLoggingLockForNonImmBuffers);
        }
        else
        {
            //
            // Set the index
            //
            Index = 0;
 
            //
            // Acquire the lock
            //
            PlatformSpinlockAcquire(&g_MessageBufferInformation[Index].BufferLockForNonImmMessage, &OldIRQL);
        }
        //
        // Set the result to True
        //
        Result = TRUE;
 
        //
        // If log message WrittenSize is above the buffer then we have to send the previous buffer
        //
        if ((g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer + BufferLen) > PacketChunkSize - 1 && g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer != 0)
        {
            //
            // Send the previous buffer (non-immediate message),
            // accumulated messages don't have priority
            //
            Result = LogCallbackSendBuffer(OPERATION_LOG_NON_IMMEDIATE_MESSAGE,
                                           (PVOID)g_MessageBufferInformation[Index].BufferForMultipleNonImmediateMessage,
                                           g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer,
                                           FALSE);
 
            //
            // Free the immediate buffer
            //
            g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer = 0;
            PlatformZeroMemory((PVOID)g_MessageBufferInformation[Index].BufferForMultipleNonImmediateMessage, PacketChunkSize);
        }
 
        //
        // We have to save the message
        //
        PlatformWriteMemory((PVOID)(g_MessageBufferInformation[Index].BufferForMultipleNonImmediateMessage +
                                    g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer),
                            LogMessage,
                            BufferLen);
 
        //
        // add the length
        //
        g_MessageBufferInformation[Index].CurrentLengthOfNonImmBuffer += BufferLen;
 
        // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
        // if not we use the windows spinlock
        //
        if (IsVmxRootMode)
        {
            SpinlockUnlock(&g_VmxRootLoggingLockForNonImmBuffers);
        }
        else
        {
            //
            // Release the lock
            //
            PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLockForNonImmMessage, OldIRQL);
        }
 
        return Result;
    }
#endif
}

LogCheckForNewMessage()

BOOLEAN LogCheckForNewMessage	(	BOOLEAN	IsVmxRoot,
		BOOLEAN	Priority )

Check if new message is available or not.

Parameters

IsVmxRoot	Check vmx root pool for message or check vmx non root pool
Priority	Whether the buffer has priority

Returns

BOOLEAN return of this function shows whether the read was successful or not (e.g FALSE shows there's no new buffer available.)

{
    UINT32 Index;
 
    if (IsVmxRoot)
    {
        Index = 1;
    }
    else
    {
        Index = 0;
    }
 
    //
    // Compute the current buffer to read
    //
    BUFFER_HEADER * Header;
 
    if (Priority)
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (g_MessageBufferInformation[Index].CurrentIndexToSendPriority * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
    else
    {
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToSend * (PacketChunkSize + sizeof(BUFFER_HEADER))));
    }
 
    if (!Header->Valid)
    {
        //
        // there is nothing to send
        //
        return FALSE;
    }
 
    //
    // If we reached here, means that there is sth to send
    //
    return TRUE;
}

LogCheckImmediateSend()

BOOLEAN LogCheckImmediateSend ( UINT32 OperationCode )

inline

Checks whether the immediate sending is needed or not.

Returns

BOOLEAN

{
    CHECK_IMMEDIATE_MESSAGE_SENDING ImmediateMessageCheck = g_MsgTracingCallbacks.CheckImmediateMessageSending;
 
    if (ImmediateMessageCheck == NULL)
    {
        //
        // As the caller didn't defined a checker we assume there is no
        // need to send messages immediately
        //
        return FALSE;
    }
 
    //
    // The user specified a vmx checker
    //
    return ImmediateMessageCheck(OperationCode);
}

LogCheckVmxOperation()

BOOLEAN LogCheckVmxOperation ( )

inline

Checks whether the message tracing operates on vmx-root mode or not.

Returns

BOOLEAN

{
    CHECK_VMX_OPERATION VmxOperationCheck = g_MsgTracingCallbacks.VmxOperationCheck;
 
    if (VmxOperationCheck == NULL)
    {
        //
        // As the caller didn't defined a checker for vmx operation, we assume
        // that it's not operating on vmx-root
        //
        return FALSE;
    }
 
    //
    // The user specified a vmx checker
    //
    return VmxOperationCheck();
}

LogInitialize()

BOOLEAN LogInitialize

(

MESSAGE_TRACING_CALLBACKS *

MsgTracingCallbacks

)

Initialize the buffer relating to log message tracing.

Parameters

MsgTracingCallbacks

specify the callbacks

Returns

BOOLEAN

{
    ULONG ProcessorsCount;
 
    ProcessorsCount = PlatformCpuGetActiveProcessorCount();
 
    //
    // Initialize buffers for trace message and data messages
    //(we have two buffers one for vmx root and one for vmx non-root)
    //
    g_MessageBufferInformation = PlatformMemAllocateZeroedNonPagedPool(sizeof(LOG_BUFFER_INFORMATION) * 2);
 
    if (!g_MessageBufferInformation)
    {
        return FALSE; // STATUS_INSUFFICIENT_RESOURCES
    }
 
    //
    // Allocate g_VmxTempMessage and g_VmxLogMessage
    //
    g_VmxTempMessage = NULL;
    g_VmxTempMessage = PlatformMemAllocateZeroedNonPagedPool(PacketChunkSize * ProcessorsCount);
 
    if (!g_VmxTempMessage)
    {
        PlatformMemFreePool(g_MessageBufferInformation);
        g_MessageBufferInformation = NULL;
        return FALSE; // STATUS_INSUFFICIENT_RESOURCES
    }
 
    g_VmxLogMessage = NULL;
    g_VmxLogMessage = PlatformMemAllocateZeroedNonPagedPool(PacketChunkSize * ProcessorsCount);
 
    if (!g_VmxLogMessage)
    {
        PlatformMemFreePool(g_MessageBufferInformation);
        g_MessageBufferInformation = NULL;
 
        PlatformMemFreePool(g_VmxTempMessage);
        g_VmxTempMessage = NULL;
 
        return FALSE; // STATUS_INSUFFICIENT_RESOURCES
    }
 
    //
    // Initialize the lock for Vmx-root mode (HIGH_IRQL Spinlock)
    //
    g_VmxRootLoggingLock = 0;
 
    //
    // Allocate buffer for messages and initialize the core buffer information
    //
    for (UINT32 i = 0; i < 2; i++)
    {
        //
        // initialize the lock
        // Actually, only the 0th buffer use this spinlock but let initialize it
        // for both but the second buffer spinlock is useless
        // as we use our custom spinlock
        //
        PlatformSpinlockInitialize(&g_MessageBufferInformation[i].BufferLock);
        PlatformSpinlockInitialize(&g_MessageBufferInformation[i].BufferLockForNonImmMessage);
 
        //
        // allocate the buffer for regular buffers
        //
        g_MessageBufferInformation[i].BufferStartAddress                   = (UINT64)PlatformMemAllocateNonPagedPool(LogBufferSize);
        g_MessageBufferInformation[i].BufferForMultipleNonImmediateMessage = (UINT64)PlatformMemAllocateNonPagedPool(PacketChunkSize);
 
        if (!g_MessageBufferInformation[i].BufferStartAddress ||
            !g_MessageBufferInformation[i].BufferForMultipleNonImmediateMessage)
        {
            return FALSE; // STATUS_INSUFFICIENT_RESOURCES
        }
 
        //
        // allocate the buffer for priority buffers
        //
        g_MessageBufferInformation[i].BufferStartAddressPriority = (UINT64)PlatformMemAllocateNonPagedPool(LogBufferSizePriority);
 
        if (!g_MessageBufferInformation[i].BufferStartAddressPriority)
        {
            return FALSE; // STATUS_INSUFFICIENT_RESOURCES
        }
 
        //
        // Zeroing the buffer
        //
        PlatformZeroMemory((PVOID)g_MessageBufferInformation[i].BufferStartAddress, LogBufferSize);
        PlatformZeroMemory((PVOID)g_MessageBufferInformation[i].BufferForMultipleNonImmediateMessage, PacketChunkSize);
        PlatformZeroMemory((PVOID)g_MessageBufferInformation[i].BufferStartAddressPriority, LogBufferSizePriority);
 
        //
        // Set the end address
        //
        g_MessageBufferInformation[i].BufferEndAddress         = (UINT64)g_MessageBufferInformation[i].BufferStartAddress + LogBufferSize;
        g_MessageBufferInformation[i].BufferEndAddressPriority = (UINT64)g_MessageBufferInformation[i].BufferStartAddressPriority + LogBufferSizePriority;
    }
 
    //
    // Copy the callbacks into the global callback holder
    //
    PlatformWriteMemory(&g_MsgTracingCallbacks, MsgTracingCallbacks, sizeof(MESSAGE_TRACING_CALLBACKS));
 
    return TRUE;
}

LogMarkAllAsRead()

UINT32 LogMarkAllAsRead

(

BOOLEAN

IsVmxRoot

)

Mark all buffers as read.

Priority buffers won't be set as read

Parameters

IsVmxRoot

Determine whether you want to read vmx root buffer or vmx non root buffer

Returns

UINT32 return count of messages that set to invalid

{
    UINT32 Index;
    UINT32 ResultsOfBuffersSetToRead = 0;
    KIRQL  OldIRQL                   = NULL_ZERO;
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        //
        // Set the index
        //
        Index = 1;
 
        //
        // Acquire the lock
        //
        SpinlockLock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Set the index
        //
        Index = 0;
 
        //
        // Acquire the lock
        //
        PlatformSpinlockAcquire(&g_MessageBufferInformation[Index].BufferLock, &OldIRQL);
    }
 
    //
    // We have iterate through the all indexes
    //
    for (SIZE_T i = 0; i < MaximumPacketsCapacity; i++)
    {
        //
        // Compute the current buffer to read
        //
        BUFFER_HEADER * Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress +
                                                   (g_MessageBufferInformation[Index].CurrentIndexToSend *
                                                    (PacketChunkSize + sizeof(BUFFER_HEADER))));
 
        if (!Header->Valid)
        {
            //
            // there is nothing to send
            //
 
            //
            // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
            // if not we use the windows spinlock
            //
            if (IsVmxRoot)
            {
                SpinlockUnlock(&g_VmxRootLoggingLock);
            }
            else
            {
                //
                // Release the lock
                //
                PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLock, OldIRQL);
            }
 
            return ResultsOfBuffersSetToRead;
        }
 
        //
        // If we reached here, means that there is sth to send
        //
        ResultsOfBuffersSetToRead++;
 
        //
        // Second, save the buffer contents
        //
        PVOID SendingBuffer = (PVOID)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToSend * (PacketChunkSize + sizeof(BUFFER_HEADER))) + sizeof(BUFFER_HEADER));
 
        //
        // Finally, set the current index to invalid as we sent it
        //
        Header->Valid = FALSE;
 
        //
        // Last step is to clear the current buffer (we can't do it once when CurrentIndexToSend is zero because
        // there might be multiple messages on the start of the queue that didn't read yet)
        // we don't free the header
        //
        PlatformZeroMemory(SendingBuffer, Header->BufferLength);
 
        //
        // Check to see whether we passed the index or not
        //
        if (g_MessageBufferInformation[Index].CurrentIndexToSend > MaximumPacketsCapacity - 2)
        {
            g_MessageBufferInformation[Index].CurrentIndexToSend = 0;
        }
        else
        {
            //
            // Increment the next index to read
            //
            g_MessageBufferInformation[Index].CurrentIndexToSend = g_MessageBufferInformation[Index].CurrentIndexToSend + 1;
        }
    }
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        SpinlockUnlock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Release the lock
        //
        PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLock, OldIRQL);
    }
 
    return ResultsOfBuffersSetToRead;
}

LogNotifyUsermodeCallback()

VOID LogNotifyUsermodeCallback	(	PKDPC	Dpc,
		PVOID	DeferredContext,
		PVOID	SystemArgument1,
		PVOID	SystemArgument2 )

Complete the IRP in IRP Pending state and fill the usermode buffers with pool data.

Parameters

Dpc
DeferredContext
SystemArgument1
SystemArgument2

Returns

VOID

{
    PNOTIFY_RECORD NotifyRecord;
    PIRP           Irp;
    UINT32         Length;
 
    UNREFERENCED_PARAMETER(Dpc);
    UNREFERENCED_PARAMETER(SystemArgument1);
    UNREFERENCED_PARAMETER(SystemArgument2);
 
    NotifyRecord = DeferredContext;
 
    ASSERT(NotifyRecord != NULL); // can't be NULL
    _Analysis_assume_(NotifyRecord != NULL);
 
    switch (NotifyRecord->Type)
    {
    case IRP_BASED:
        Irp = NotifyRecord->Message.PendingIrp;
 
        if (Irp != NULL)
        {
            PCHAR              OutBuff;       // pointer to output buffer
            ULONG              InBuffLength;  // Input buffer length
            ULONG              OutBuffLength; // Output buffer length
            PIO_STACK_LOCATION IrpSp;
 
            //
            // Make suree that concurrent calls to notify function never occurs
            //
            if (!(Irp->CurrentLocation <= Irp->StackCount + 1))
            {
                PlatformDbgPrint("Err, probably two or more functions called DPC for an object");
                return;
            }
 
            IrpSp         = PlatformIoGetCurrentIrpStackLocation(Irp);
            InBuffLength  = IrpSp->Parameters.DeviceIoControl.InputBufferLength;
            OutBuffLength = IrpSp->Parameters.DeviceIoControl.OutputBufferLength;
 
            if (!InBuffLength || !OutBuffLength)
            {
                Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
                PlatformIoCompleteRequest(Irp, IO_NO_INCREMENT);
                break;
            }
 
            //
            // Check again that SystemBuffer is not null
            //
            if (!Irp->AssociatedIrp.SystemBuffer)
            {
                //
                // Buffer is invalid
                //
                return;
            }
 
            OutBuff = Irp->AssociatedIrp.SystemBuffer;
            Length  = 0;
 
            //
            // Read Buffer might be empty (nothing to send)
            //
            if (!LogReadBuffer(NotifyRecord->CheckVmxRootMessagePool, OutBuff, &Length))
            {
                //
                // we have to return here as there is nothing to send here
                //
                Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
                PlatformIoCompleteRequest(Irp, IO_NO_INCREMENT);
                break;
            }
 
            Irp->IoStatus.Information = Length;
 
            Irp->IoStatus.Status = STATUS_SUCCESS;
            PlatformIoCompleteRequest(Irp, IO_NO_INCREMENT);
        }
        break;
 
    case EVENT_BASED:
        //
        // Signal the Event created in user-mode.
        //
        PlatformEventSet(NotifyRecord->Message.Event, 0, FALSE);
 
        //
        // Dereference the object as we are done with it.
        //
        PlatformObjectDereference(NotifyRecord->Message.Event);
 
        break;
 
    default:
        ASSERT(FALSE);
        break;
    }
 
    if (NotifyRecord != NULL)
    {
        PlatformMemFreePool(NotifyRecord);
    }
}

LogReadBuffer()

BOOLEAN LogReadBuffer	(	BOOLEAN	IsVmxRoot,
		PVOID	BufferToSaveMessage,
		UINT32 *	ReturnedLength )

Attempt to read the buffer.

Parameters

IsVmxRoot	Determine whether you want to read vmx root buffer or vmx non root buffer
BufferToSaveMessage	Target buffer to save the message
ReturnedLength	The actual length of the buffer that this function used it

Returns

BOOLEAN return of this function shows whether the read was successful or not (e.g FALSE shows there's no new buffer available.)

{
    UINT32  Index;
    BOOLEAN PriorityMessageIsAvailable = FALSE;
    KIRQL   OldIRQL                    = NULL_ZERO;
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        //
        // Set the index
        //
        Index = 1;
 
        //
        // Acquire the lock
        //
        SpinlockLock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Set the index
        //
        Index = 0;
 
        //
        // Acquire the lock
        //
        PlatformSpinlockAcquire(&g_MessageBufferInformation[Index].BufferLock, &OldIRQL);
    }
 
    //
    // Compute the current buffer to read
    //
    BUFFER_HEADER * Header;
 
    //
    // Check for priority message
    //
    Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (g_MessageBufferInformation[Index].CurrentIndexToSendPriority * (PacketChunkSize + sizeof(BUFFER_HEADER))));
 
    if (!Header->Valid)
    {
        //
        // Check for regular message
        //
        Header = (BUFFER_HEADER *)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToSend * (PacketChunkSize + sizeof(BUFFER_HEADER))));
 
        if (!Header->Valid)
        {
            //
            // there is nothing to send
            //
 
            //
            // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
            // if not we use the windows spinlock
            //
            if (IsVmxRoot)
            {
                SpinlockUnlock(&g_VmxRootLoggingLock);
            }
            else
            {
                //
                // Release the lock
                //
                PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLock, OldIRQL);
            }
 
            return FALSE;
        }
    }
    else
    {
        PriorityMessageIsAvailable = TRUE;
    }
 
    //
    // If we reached here, means that there is sth to send
    //
 
    //
    // First copy the header
    //
    PlatformWriteMemory(BufferToSaveMessage, &Header->OperationNumber, sizeof(UINT32));
 
    //
    // Second, save the buffer contents
    //
    PVOID SendingBuffer;
 
    if (PriorityMessageIsAvailable)
    {
        SendingBuffer = (PVOID)((UINT64)g_MessageBufferInformation[Index].BufferStartAddressPriority + (g_MessageBufferInformation[Index].CurrentIndexToSendPriority * (PacketChunkSize + sizeof(BUFFER_HEADER))) + sizeof(BUFFER_HEADER));
    }
    else
    {
        SendingBuffer = (PVOID)((UINT64)g_MessageBufferInformation[Index].BufferStartAddress + (g_MessageBufferInformation[Index].CurrentIndexToSend * (PacketChunkSize + sizeof(BUFFER_HEADER))) + sizeof(BUFFER_HEADER));
    }
 
    //
    // Because we want to pass the header of usermode header
    //
    PVOID SavingAddress = (PVOID)((UINT64)BufferToSaveMessage + sizeof(UINT32));
 
    PlatformWriteMemory(SavingAddress, SendingBuffer, Header->BufferLength);
 
#if ShowMessagesOnDebugger
 
    //
    // Means that show just messages
    //
    if (Header->OperationNumber <= OPERATION_LOG_NON_IMMEDIATE_MESSAGE)
    {
        //
        // We're in Dpc level here so it's safe to use DbgPrint
        // DbgPrint limitation is 512 Byte
        //
        if (Header->BufferLength > DbgPrintLimitation)
        {
            for (SIZE_T i = 0; i <= Header->BufferLength / DbgPrintLimitation; i++)
            {
                if (i != 0)
                {
                    PlatformDbgPrint("%s", (CHAR *)((UINT64)SendingBuffer + (DbgPrintLimitation * i) - 2));
                }
                else
                {
                    PlatformDbgPrint("%s", (CHAR *)((UINT64)SendingBuffer + (DbgPrintLimitation * i)));
                }
            }
        }
        else
        {
            PlatformDbgPrint("%s", (CHAR *)SendingBuffer);
        }
    }
#endif
 
    //
    // Finally, set the current index to invalid as we sent it
    //
    Header->Valid = FALSE;
 
    //
    // Set the length to show as the ReturnedByted in usermode ioctl function + size of header
    //
    *ReturnedLength = Header->BufferLength + sizeof(UINT32);
 
    //
    // Last step is to clear the current buffer (we can't do it once when CurrentIndexToSend is zero because
    // there might be multiple messages on the start of the queue that didn't read yet)
    // we don't free the header
    //
    PlatformZeroMemory(SendingBuffer, Header->BufferLength);
 
    if (PriorityMessageIsAvailable)
    {
        //
        // Check to see whether we passed the index or not
        //
        if (g_MessageBufferInformation[Index].CurrentIndexToSendPriority > MaximumPacketsCapacityPriority - 2)
        {
            g_MessageBufferInformation[Index].CurrentIndexToSendPriority = 0;
        }
        else
        {
            //
            // Increment the next index to read
            //
            g_MessageBufferInformation[Index].CurrentIndexToSendPriority = g_MessageBufferInformation[Index].CurrentIndexToSendPriority + 1;
        }
    }
    else
    {
        //
        // Check to see whether we passed the index or not
        //
        if (g_MessageBufferInformation[Index].CurrentIndexToSend > MaximumPacketsCapacity - 2)
        {
            g_MessageBufferInformation[Index].CurrentIndexToSend = 0;
        }
        else
        {
            //
            // Increment the next index to read
            //
            g_MessageBufferInformation[Index].CurrentIndexToSend = g_MessageBufferInformation[Index].CurrentIndexToSend + 1;
        }
    }
 
    //
    // Check if we're in Vmx-root, if it is then we use our customized HIGH_IRQL Spinlock,
    // if not we use the windows spinlock
    //
    if (IsVmxRoot)
    {
        SpinlockUnlock(&g_VmxRootLoggingLock);
    }
    else
    {
        //
        // Release the lock
        //
        PlatformSpinlockRelease(&g_MessageBufferInformation[Index].BufferLock, OldIRQL);
    }
 
    return TRUE;
}

LogRegisterEventBasedNotification()

BOOLEAN LogRegisterEventBasedNotification

(

PVOID

TargetIrp

)

Create an event-based usermode notifying mechanism.

Parameters

TargetIrp

Returns

BOOLEAN

{
    PNOTIFY_RECORD          NotifyRecord;
    NTSTATUS                Status;
    PIO_STACK_LOCATION      IrpStack;
    PREGISTER_NOTIFY_BUFFER RegisterEvent;
    PIRP                    Irp = (PIRP)TargetIrp;
 
    IrpStack      = PlatformIoGetCurrentIrpStackLocation(Irp);
    RegisterEvent = (PREGISTER_NOTIFY_BUFFER)Irp->AssociatedIrp.SystemBuffer;
 
    //
    // Allocate a record and save all the event context
    //
    NotifyRecord = PlatformMemAllocateNonPagedPoolWithQuota(sizeof(NOTIFY_RECORD));
 
    if (NULL == NotifyRecord)
    {
        PlatformDbgPrint("Err, unable to allocate memory for notify record\n");
        return FALSE;
    }
 
    NotifyRecord->Type = EVENT_BASED;
 
    PlatformDpcInitialize(&NotifyRecord->Dpc,        // Dpc
                          LogNotifyUsermodeCallback, // DeferredRoutine
                          NotifyRecord               // DeferredContext
    );
 
    //
    // Get the object pointer from the handle
    // Note we must be in the context of the process that created the handle
    //
    Status = PlatformObjectReferenceByHandle(RegisterEvent->hEvent,
                                             SYNCHRONIZE | EVENT_MODIFY_STATE,
                                             *ExEventObjectType,
                                             Irp->RequestorMode,
                                             &NotifyRecord->Message.Event,
                                             NULL);
 
    if (!NT_SUCCESS(Status))
    {
        PlatformDbgPrint("Err, unable to reference user mode event object, status = 0x%x\n", Status);
        PlatformMemFreePool(NotifyRecord);
        return FALSE;
    }
 
    //
    // Insert dpc to the queue
    //
    PlatformDpcInsertQueueDpc(&NotifyRecord->Dpc, NotifyRecord, NULL);
 
    return TRUE;
}

LogRegisterIrpBasedNotification()

BOOLEAN LogRegisterIrpBasedNotification	(	PVOID	TargetIrp,
		LONG *	Status )

Register a new IRP Pending thread which listens for new buffers.

Parameters

TargetIrp
Status

Returns

BOOLEAN

{
    PNOTIFY_RECORD          NotifyRecord;
    PIO_STACK_LOCATION      IrpStack;
    PREGISTER_NOTIFY_BUFFER RegisterEvent;
    PIRP                    Irp = (PIRP)TargetIrp;
 
    //
    // check if current core has another thread with pending IRP,
    // if no then put the current thread to pending
    // otherwise return and complete thread with STATUS_SUCCESS as
    // there is another thread waiting for message
    //
 
    if (g_GlobalNotifyRecord == NULL)
    {
        IrpStack      = PlatformIoGetCurrentIrpStackLocation(Irp);
        RegisterEvent = (PREGISTER_NOTIFY_BUFFER)Irp->AssociatedIrp.SystemBuffer;
 
        //
        // Allocate a record and save all the event context
        //
        NotifyRecord = PlatformMemAllocateNonPagedPoolWithQuota(sizeof(NOTIFY_RECORD));
 
        if (NULL == NotifyRecord)
        {
            *Status = (LONG)STATUS_INSUFFICIENT_RESOURCES;
            return FALSE;
        }
 
        NotifyRecord->Type               = IRP_BASED;
        NotifyRecord->Message.PendingIrp = Irp;
 
        PlatformDpcInitialize(&NotifyRecord->Dpc,        // Dpc
                              LogNotifyUsermodeCallback, // DeferredRoutine
                              NotifyRecord               // DeferredContext
        );
 
        PlatformIoMarkIrpPending(Irp);
 
        //
        // check for new message (for both Vmx-root mode or Vmx non root-mode)
        // First, we check for priority messages in both buffers then we check
        // for regular messages
        //
        if (LogCheckForNewMessage(FALSE, TRUE))
        {
            //
            // check vmx non-root (priority buffers)
            //
            NotifyRecord->CheckVmxRootMessagePool = FALSE;
 
            //
            // Insert dpc to queue
            //
            PlatformDpcInsertQueueDpc(&NotifyRecord->Dpc, NotifyRecord, NULL);
        }
        else if (LogCheckForNewMessage(TRUE, TRUE))
        {
            //
            // check vmx root (priority buffers)
            //
            NotifyRecord->CheckVmxRootMessagePool = TRUE;
            //
            // Insert dpc to queue
            //
            PlatformDpcInsertQueueDpc(&NotifyRecord->Dpc, NotifyRecord, NULL);
        }
        else if (LogCheckForNewMessage(FALSE, FALSE))
        {
            //
            // check vmx non-root
            //
            NotifyRecord->CheckVmxRootMessagePool = FALSE;
 
            //
            // Insert dpc to queue
            //
            PlatformDpcInsertQueueDpc(&NotifyRecord->Dpc, NotifyRecord, NULL);
        }
        else if (LogCheckForNewMessage(TRUE, FALSE))
        {
            //
            // check vmx root
            //
            NotifyRecord->CheckVmxRootMessagePool = TRUE;
            //
            // Insert dpc to queue
            //
            PlatformDpcInsertQueueDpc(&NotifyRecord->Dpc, NotifyRecord, NULL);
        }
        else
        {
            //
            // Set the notify routine to the global structure
            //
            g_GlobalNotifyRecord = NotifyRecord;
        }
        //
        // We will return pending as we have marked the IRP pending
        //
 
        *Status = (LONG)STATUS_PENDING;
        return TRUE;
    }
    else
    {
        *Status = (LONG)STATUS_SUCCESS;
        return TRUE;
    }
}

LogSendImmediateMessage()

BOOLEAN LogSendImmediateMessage ( CHAR * OptionalBuffer, UINT32 OptionalBufferLength, UINT32 OperationCode )

inline

Checks whether the immediate sending is needed or not.

Parameters

OptionalBuffer
OptionalBufferLength
OperationCode

Returns

BOOLEAN

{
    SEND_IMMEDIATE_MESSAGE SendImmediateMessage = g_MsgTracingCallbacks.SendImmediateMessage;
 
    if (SendImmediateMessage == NULL)
    {
        //
        // As the caller didn't defined a checker we assume there is no
        // need to send messages immediately
        //
        return FALSE;
    }
 
    //
    // The user specified a vmx checker
    //
    return SendImmediateMessage(OptionalBuffer, OptionalBufferLength, OperationCode);
}

LogUnInitialize()

VOID LogUnInitialize

(

)

Uninitialize the buffer relating to log message tracing.

Returns

VOID

{
    //
    // de-allocate buffer for messages and initialize the core buffer information (for vmx-root core)
    //
    for (int i = 0; i < 2; i++)
    {
        //
        // Check if the buffer is allocated or not
        //
        if (g_MessageBufferInformation == NULL64_ZERO)
        {
            continue; // No need to free the buffers
        }
 
        //
        // Free each buffers
        //
        if (g_MessageBufferInformation[i].BufferStartAddress != NULL64_ZERO)
        {
            PlatformMemFreePool((PVOID)g_MessageBufferInformation[i].BufferStartAddress);
        }
 
        if (g_MessageBufferInformation[i].BufferStartAddressPriority != NULL64_ZERO)
        {
            PlatformMemFreePool((PVOID)g_MessageBufferInformation[i].BufferStartAddressPriority);
        }
 
        if (g_MessageBufferInformation[i].BufferForMultipleNonImmediateMessage != NULL64_ZERO)
        {
            PlatformMemFreePool((PVOID)g_MessageBufferInformation[i].BufferForMultipleNonImmediateMessage);
        }
    }
 
    //
    // de-allocate buffers for trace message and data messages if they are allocated
    //
    if (g_MessageBufferInformation != NULL64_ZERO)
    {
        PlatformMemFreePool((PVOID)g_MessageBufferInformation);
        g_MessageBufferInformation = NULL;
    }
}