内核中获取进程路径学习

NTSTATUS PsGetProcessPathByPid( IN ULONG Pid ,char* FilePath)
{
NTSTATUS       status;

char       path[256] = {0};
char       disk[10] = {0};
STRING        ansi_path;
STRING        ansi_disk;
UNICODE_STRING     uni_path;
UNICODE_STRING     uni_disk;
  
PEPROCESS       pEprocess;
PFILE_OBJECT      FileObject;
PVOID       Object;

status = PsLookupProcessByProcessId(Pid,&pEprocess);

if(!NT_SUCCESS(status))
{
   DbgPrint("EPROCESS Error");
   return STATUS_UNSUCCESSFUL;
} DbgPrint("EPROCESS 0x%0.8X",pEprocess);

if( !MmIsAddressValid( (PULONG)( (ULONG)pEprocess+0x138 ) ) )//EPROCESS+0x138 -> SectionObject

{   DbgPrint("SectionObject Error");
   return STATUS_UNSUCCESSFUL;
} Object = (PVOID)(*(PULONG)((ULONG)pEprocess+0x138));

if( !MmIsAddressValid( (PULONG)( (ULONG)Object+0x014 ) ) )//SectionObject+0x014 -> Segment
{
   DbgPrint("Segment Error");
   return STATUS_UNSUCCESSFUL;
} Object = (PVOID)(*(PULONG)( (ULONG)Object+0x014 ));
  
if( !MmIsAddressValid( (PULONG)((ULONG)Object+0x000) ) )//Segment+0x000 -> ControlAera
{
   DbgPrint("ControlAera Error");
   return STATUS_UNSUCCESSFUL;
} Object = (PVOID)(*(PULONG)( (ULONG)Object+0x000 ));
  
if( !MmIsAddressValid( (PULONG)( (ULONG)Object+0x024 ) ) )//ControlAera+0x024 -> FilePointer(FileObject)
{
   DbgPrint("FilePointer Error");
   return STATUS_UNSUCCESSFUL;
} Object = (PVOID)(*(PULONG)( (ULONG)Object+0x024 ));
  
FileObject = Object;
ObReferenceObjectByPointer((PVOID)FileObject,0,NULL,KernelMode);
RtlInitUnicodeString(&uni_path,FileObject->FileName.Buffer); //获取路径名
RtlVolumeDeviceToDosName(FileObject->DeviceObject,&uni_disk); //获取盘符名
ObDereferenceObject(FileObject);

RtlUnicodeStringToAnsiString(&ansi_path,&uni_path,TRUE);
RtlUnicodeStringToAnsiString(&ansi_disk,&uni_disk,TRUE);

strcat(path,&ansi_path.Buffer[0]);
strcat(disk,&ansi_disk.Buffer[0]);

RtlFreeAnsiString(&ansi_path);
RtlFreeAnsiString(&ansi_disk);
  
if( strlen(path)+strlen(disk) < 256 )
{
   strcat(FilePath,disk);
   strcat(FilePath,path);
}
else
{
   strcat(FilePath,disk);
   memcpy( FilePath,path,256-strlen(disk)-1 );
   *(FilePath + 256) = 0;
}
return STATUS_SUCCESS;
}