pinvoke.net: Edit: ntdll.ntqueryinformationprocess

@msdn=https://docs.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-ntqueryinformationprocess
@pinvoke=http://pinvoke.net/$$$.htm

Summary: Retrieves information about the specified process.  This function is available in Windows 2000 and Windows XP, but it may be altered or unavailable in subsequent versions.

!!!!C# Signature:
 [DllImport("ntdll.dll", SetLastError=true)]
 static extern int NtQueryInformationProcess(IntPtr processHandle, int processInformationClass, IntPtr processInformation, uint processInformationLength, IntPtr returnLength);

!!!!or:
 [DllImport("NTDLL.DLL", SetLastError=true)]
 static extern int NtQueryInformationProcess(IntPtr hProcess, PROCESSINFOCLASS pic, out PROCESS_BASIC_INFORMATION pbi, int cb, out int pSize);

!!!!or:
 [DllImport("ntdll.dll", PreserveSig = false, SetLastError = true)]
 public static extern void NtQueryInformationProcess(IntPtr ProcessHandle, PROCESSINFOCLASS ProcessInformationClass, out PROCESS_EXTENDED_BASIC_INFORMATION ProcessInformation, uint ProcessInformationLength, out uint ReturnLength);

!!!!VB Signature:
 Declare Function NtQueryInformationProcess Lib "ntdll.dll" ( _
   processHandle As IntPtr, processInformationClass As Integer, _
   processInformation As IntPtr, processInformationLength As Integer, _
   returnLength As IntPtr) As Integer
!!!!Boo Signature:
 [DllImport("ntdll.dll", SetLastError : true)]
 def NtQueryInformationProcess(
     hProcess as IntPtr,
     processInformationClass as PROCESSINFOCLASS,
     ref processInformation as PROCESS_BASIC_INFORMATION,
     processInformationLength as UInt32,
     ref returnLength as UInt32) as UInt32:
     pass
!!!!User-Defined Types:
 [PROCESSINFOCLASS], [PROCESS_BASIC_INFORMATION], [PROCESS_EXTENDED_BASIC_INFORMATION]
 // deleted a lot of unused entries
 enum PROCESSINFOCLASS:
     ProcessBasicInformation = 0x00
     ProcessDebugPort = 0x07
     ProcessExceptionPort = 0x08
     ProcessAccessToken = 0x09
     ProcessWow64Information = 0x1A
     ProcessImageFileName = 0x1B
     ProcessDebugObjectHandle = 0x1E
     ProcessDebugFlags = 0x1F
     ProcessExecuteFlags = 0x22
     ProcessInstrumentationCallback = 0x28
     MaxProcessInfoClass = 0x64
 
 [StructLayout(LayoutKind.Sequential)]
 struct PROCESS_BASIC_INFORMATION:
     Reserved1 as IntPtr
     PebAddress as IntPtr
     [MarshalAs(UnmanagedType.ByValArray, SizeConst : 2)]
     Reserved2 as (IntPtr)
     UniquePid as IntPtr
     Reserved3 as IntPtr
!!!!Notes:
See also OpenProcess, CloseHandle.

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:

public static IntPtr GetPEBAddress()
        {
            //Get a handle to our own process
            IntPtr hProc = OpenProcess(0x001F0FFF, false, Process.GetCurrentProcess().Id);
            //Allocate memory for a new PROCESS_BASIC_INFORMATION structure
            IntPtr pbi = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(PROCESS_BASIC_INFORMATION)));
            //Allocate memory for a long
            IntPtr outLong = Marshal.AllocHGlobal(sizeof(long));
            IntPtr outPtr = IntPtr.Zero;

int queryStatus = false;

//Store API call success in a boolean
            queryStatus = NtQueryInformationProcess(hProc, 0, pbi, (uint)Marshal.SizeOf(typeof(PROCESS_BASIC_INFORMATION)), outLong);
            
            //Close handle and free allocated memory
            CloseHandle(hProc);
            Marshal.FreeHGlobal(outLong);

//STATUS_SUCCESS = 0, so if API call was successful querySuccess should contain 0 ergo we reverse the check.
            if(!queryStatus )
                outPtr = PtrToStructure<PROCESS_BASIC_INFORMATION>(pbi, typeof(PROCESS_BASIC_INFORMATION)).PebBaseAddress;

//Free allocated space
            Marshal.FreeHGlobal(pbi);

//Return pointer to PEB base address
            return outPtr;
        }

!!!!Or:

public static int GetParentProcessId()
    {
    	PROCESS_BASIC_INFORMATION pbi = new PROCESS_BASIC_INFORMATION();
                
    	//Get a handle to our own process
    	IntPtr hProc = OpenProcess((ProcessAccessFlags)0x001F0FFF, false, Process.GetCurrentProcess().Id);

try
    	{
    	    int sizeInfoReturned;
    	    int queryStatus = NtQueryInformationProcess(hProc, (PROCESSINFOCLASS)0, ref pbi, pbi.Size, out sizeInfoReturned);
    	}
    	finally
    	{
    	    if (!hProc.Equals(IntPtr.Zero))
    	    {
    	        //Close handle and free allocated memory
    	        CloseHandle(hProc);
    	        hProc = IntPtr.Zero;
    	    }
    	}

return (int)pbi.InheritedFromUniqueProcessId;
    }

!!!!Alternative Managed API:
Do you know one?  Please contribute it!

Documentation: NtQueryInformationProcess@msdn on MSDN