Log.c

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#include "Log.h"
#include <stdarg.h>
#include <stdio.h>
#pragma hdrstop

BOOLEAN LogMessage(PCHAR szFormat, ...)
{
    ULONG Length;
    char messagebuf[256];
    va_list va;
    IO_STATUS_BLOCK  IoStatus;
    OBJECT_ATTRIBUTES objectAttributes;
    NTSTATUS status;
    HANDLE FileHandle;
    UNICODE_STRING fileName;


    //format the string
    va_start(va,szFormat);
    vsprintf(messagebuf,szFormat,va);
    va_end(va);

    //get a handle to the log file object
    fileName.Buffer = NULL;
    fileName.Length = 0;
    fileName.MaximumLength = sizeof(DEFAULT_LOG_FILE_NAME) + sizeof(UNICODE_NULL);
    fileName.Buffer = ExAllocatePool(PagedPool,
                                        fileName.MaximumLength);
    if (!fileName.Buffer)
    {
        return FALSE;
    }
    RtlZeroMemory(fileName.Buffer, fileName.MaximumLength);
    status = RtlAppendUnicodeToString(&fileName, (PWSTR)DEFAULT_LOG_FILE_NAME);

    //DbgPrint("\n Initializing Object attributes");

    InitializeObjectAttributes (&objectAttributes,
                                (PUNICODE_STRING)&fileName,
                                OBJ_CASE_INSENSITIVE,
                                NULL,
                                NULL );

    DbgPrint("\n BusLogic - Creating the file");

    status = ZwCreateFile(&FileHandle,
                      FILE_APPEND_DATA,
                      &objectAttributes,
                      &IoStatus,
                      0,
                      FILE_ATTRIBUTE_NORMAL,
                      FILE_SHARE_WRITE,
                      FILE_OPEN_IF,
                      FILE_SYNCHRONOUS_IO_NONALERT,
                      NULL,
                      0 );

    if(NT_SUCCESS(status))
    {
        CHAR buf[300];
        LARGE_INTEGER time;
        KeQuerySystemTime(&time);

        DbgPrint("\n BusLogic - Created the file");

        //put a time stamp on the output message
        sprintf(buf,"%10u-%10u  %s",time.HighPart,time.LowPart,messagebuf);

        //format the string to make sure it appends a newline carrage-return to the
        //end of the string.
        Length=strlen(buf);
        if(buf[Length-1]=='\n')
        {
            buf[Length-1]='\r';
            strcat(buf,"\n");
            Length++;
        }
        else
        {
            strcat(buf,"\r\n");
            Length+=2;
        }

        buf[Length+1] = '\0';
        DbgPrint("\n BusLogic - Writing to the file");
        DbgPrint("\n BusLogic - Buf = %s", buf);

        status = ZwWriteFile(FileHandle,
                  NULL,
                  NULL,
                  NULL,
                  &IoStatus,
                  buf,
                  Length,
                  NULL,
                  NULL );

        ZwClose(FileHandle);
    }
    if (fileName.Buffer)
        ExFreePool (fileName.Buffer);

    return STATUS_SUCCESS;
}