I made a class to start child process that inherit new pipes for standard input/output/error. All is working fine in 32bits: I can write in child StdIn and read child StdOut/Err without problem (the child process can also read the new StdIn pipe and write in the new stdOut/Err pipes).
But, if I compile my parent process in 64bits, the child process (32 and 64bits) cannot read the new pipes.
Parent | Child | RedirectPipes | Result (In Child process)
32bits | 32/64 | In+Out | GOOD
64bits | 32/64 | In+Out | Access Denied for StdIn (Console.ReadLine)
64bits | 32/64 | In | *** No error but no data for StdIn.
*** When I don't redirect the Output pipe, I can manually write (with my keyboard) in the new window and the child receives that data. So the stdIn isn't redirect.
In all case, no error in parent process
I tried to adjust the SecurityDescriptor of the SECURITY_ATTRIBUTES but without success. I know that the SECURITY_ATTRIBUTES structure has a different size in 64bits but I'm not sure if it can be a problem and how to manage that.
Do you have any suggestions? Questions?
Thank you
If you want to test, I made a smaller project with only the minimal.
Parent code :
using System;
using System.IO;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using Microsoft.Win32.SafeHandles;
namespace Shell.TestShell
{
class TestShell
{
static void Main()
{
var OneShell = new Shell2();
}
}
class Shell2
{
public const Int32 STARTF_USESTDHANDLES = 0x100;
public const Int32 STARTF_USESHOWWINDOW = 1;
public const UInt16 SW_SHOW = 5;
public const UInt16 SW_HIDE = 0;
[Flags()]
public enum CreateProcessFlags
{
CREATE_SUSPENDED = 0x4,
DETACHED_PROCESS = 0x8,
CREATE_DEFAULT_ERROR_MODE = 0x4000000,
CREATE_NEW_CONSOLE = 0x10,
CREATE_NEW_PROCESS_GROUP = 0x200,
CREATE_NO_WINDOW = 0x8000000,
CREATE_SEPARATE_WOW_VDM = 0x800,
CREATE_UNICODE_ENVIRONMENT = 0x400,
IDLE_PRIORITY_CLASS = 0x40,
BELOW_NORMAL_PRIORITY_CLASS = 0x4000,
ABOVE_NORMAL_PRIORITY_CLASS = 0x8000,
NORMAL_PRIORITY_CLASS = 0x20,
HIGH_PRIORITY_CLASS = 0x80,
REALTIME_PRIORITY_CLASS = 0x100
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct StartupInfo
{
public int cb;
public String reserved;
public String desktop;
public String title;
public int x;
public int y;
public int xSize;
public int ySize;
public int xCountChars;
public int yCountChars;
public int fillAttribute;
public int flags;
public UInt16 showWindow;
public UInt16 reserved2;
public byte reserved3;
public SafeFileHandle hStdInput;
public SafeFileHandle hStdOutput;
public SafeFileHandle hStdError;
}
public struct ProcessInformation
{
public IntPtr process;
public IntPtr thread;
public int processId;
public int threadId;
}
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool CreateProcess(string lpApplicationName,
string lpCommandLine,
IntPtr lpProcessAttributes,
IntPtr lpThreadAttributes,
bool bInheritHandles,
CreateProcessFlags dwCreationFlags,
IntPtr lpEnvironment,
string lpCurrentDirectory,
ref StartupInfo lpStartupInfo,
out ProcessInformation lpProcessInformation);
[StructLayout(LayoutKind.Sequential)]
public struct SECURITY_ATTRIBUTES
{
public int Length;
public IntPtr SecurityDescriptor;
public bool InheritHandle;
}
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool CreatePipe(out SafeFileHandle hReadPipe, out SafeFileHandle hWritePipe, ref SECURITY_ATTRIBUTES lpPipeAttributes, uint nSize);
public Shell2()
{
StartupInfo Shell2StartupInfo = new StartupInfo();
Shell2StartupInfo.flags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
Shell2StartupInfo.showWindow = SW_SHOW; // SW_SHOW for testing only
Shell2StartupInfo.reserved = null;
Shell2StartupInfo.cb = Marshal.SizeOf(Shell2StartupInfo);
SECURITY_ATTRIBUTES lpPipeAttributesInput = new SECURITY_ATTRIBUTES();
lpPipeAttributesInput.InheritHandle = true;
lpPipeAttributesInput.Length = Marshal.SizeOf(lpPipeAttributesInput);
lpPipeAttributesInput.SecurityDescriptor = IntPtr.Zero;
// Parent pipes
SafeFileHandle StandardInputWriteHandle;
SafeFileHandle StandardOutputReadHandle;
// Child pipes
SafeFileHandle StandardInputReadHandle;
SafeFileHandle StandardOutputWriteHandle;
// New pipes for StdIN
if (!CreatePipe(out StandardInputReadHandle, out StandardInputWriteHandle, ref lpPipeAttributesInput, 0))
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
// New pipes for StdOUT
if (!CreatePipe(out StandardOutputReadHandle, out StandardOutputWriteHandle, ref lpPipeAttributesInput, 0))
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
// Redirect child pipes
Shell2StartupInfo.hStdInput = StandardInputReadHandle;
Shell2StartupInfo.hStdOutput = StandardOutputWriteHandle;
//Shell2StartupInfo.hStdOutput = new SafeFileHandle(IntPtr.Zero, false);
Shell2StartupInfo.hStdError = new SafeFileHandle(IntPtr.Zero, false);
String PathProgram;
// My testing child .Net Application
//PathProgram = @"C:\Temp\ConsoleEcho32.exe";
//PathProgram = @"C:\Temp\ConsoleEcho64.exe";
// cmd.exe same platform (32/64bits) as parent process
PathProgram = @"C:\Windows\System32\cmd.exe";
// Force 32 bits cmd.exe child from 64bits parent
//PathProgram = @"C:\Windows\SysWOW64\cmd.exe";
// Force 64 bits cmd.exe child from 32bits parent
//PathProgram = @"C:\Windows\sysnative\cmd.exe";
FileStream fsOUT = new FileStream(StandardOutputReadHandle, FileAccess.Read, 4096, false);
StreamReader SR = new StreamReader(fsOUT, Console.OutputEncoding);
FileStream fsIN = new FileStream(StandardInputWriteHandle, FileAccess.Write, 4096, false);
StreamWriter SW = new StreamWriter(fsIN, Console.InputEncoding);
ProcessInformation ProcessInfo;
if (!CreateProcess(PathProgram, @"",
IntPtr.Zero,
IntPtr.Zero,
true,
CreateProcessFlags.CREATE_NEW_CONSOLE, // CREATE_NEW_CONSOLE for testing only
IntPtr.Zero, @"C:\temp",
ref Shell2StartupInfo,
out ProcessInfo))
{
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error());
}
Console.WriteLine("Child started");
SW.WriteLine("echo Result should be in child process StdOUT");
//SW.WriteLine(@"echo b > c:\temp\ttt.txt"); // test StdIN without StdOutput
SW.Flush();
for (int i = 1; i <= 5; i++)
{
Console.WriteLine("Child output " + i + " : "+ SR.ReadLine());
}
SW.Close();
Console.WriteLine("END");
Console.ReadLine();
}
}
}
You can use cmd.exe as child process or, if you prefer, my ConsoleEcho code
using System;
using System.IO;
using System.Runtime.InteropServices;
namespace ConsoleEcho
{
class Program
{
static void Main(string[] args)
{
String NewLine = Environment.NewLine;
String PathLog = @"c:\temp\logConsoleEcho.txt";
try
{
File.Delete(PathLog);
File.AppendAllText(PathLog, DateTime.Now.ToString() + " ConsoleEcho begin" + NewLine);
Console.WriteLine(DateTime.Now.ToString() + " ConsoleEcho begin");
File.AppendAllText(PathLog, "After first WriteLine" + NewLine); // Useful if the process crash of freeze while writing to StdOut
String Input;
do
{
Input = Console.ReadLine();
File.AppendAllText(PathLog, Input + NewLine);
Console.WriteLine(Input);
} while (Input != null);
}
catch (Exception Ex)
{
int error = Marshal.GetLastWin32Error();
File.AppendAllText(PathLog, "The last Win32 Error was: " + error + NewLine);
Console.WriteLine("The last Win32 Error was: " + error);
File.AppendAllText(PathLog, Ex.ToString() + NewLine);
Console.WriteLine(Ex.ToString());
File.AppendAllText(PathLog, Ex.HResult.ToString() + NewLine);
Console.WriteLine(Ex.HResult.ToString());
System.Threading.Thread.Sleep(30000);
}
}
}
}
Using cmd.exe, with a 32bits parent, you should get:
Parent output
Child started
Child output 1 : Microsoft Windows [Version 10.0.18363.1198]
Child output 2 : (c) 2019 Microsoft Corporation. All rights reserved.
Child output 3 :
Child output 4 : C:\temp>echo Result should be in child process StdOUT
Child output 5 : Result should be in child process StdOUT
END
Child Output : Nothing
Using cmd.exe, with a 64bits parent, you should get:
Parent output
Child started
Child Output : Nothing and the cmd.exe will close
Using ConsoleEcho.exe, with a 32bits parent, you should get:
Parent output
Child started
Child output 1 : 2021-01-22 13:52:24 ConsoleEcho begin
Child output 2 : echo Result should be in child process StdOUT
Child Output : Nothing
Using ConsoleEcho.exe, with a 64bits parent, you should get:
Parent output
Child started
Child Output
2021-01-22 13:55:15 ConsoleEcho begin
The last Win32 Error was: 5
System.UnauthorizedAccessException: Access to the path is denied.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.__ConsoleStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.StreamReader.ReadBuffer()
at System.IO.StreamReader.ReadLine()
at System.IO.TextReader.SyncTextReader.ReadLine()
at System.Console.ReadLine()
at ConsoleEcho.Program.Main(String[] args) in \\..\ConsoleEcho\Program.cs:line 25
-2147024891
Xanatos found the solution.
Here is my approach/mistake if it can help someone :
It was the first time for me with createProcess+CreatePipe and I started with pInvoke definition. But, I had some problem with the redirection of pipes. So, I take a "working" example on Internet (that had this byte/IntPtr definition error). This code was working in 32bits and come with a lot of struct/API definitions. I didn't compared/challenged these definitions against pinvoke.
When I rebuild my project in 64bits, I got the access denied. I searched for hints/solutions and found the "same" error (access denied) with CreateProcess/CreatePipe in 64bits only. According to what I found, their problems was related to the struct SECURITY_ATTRIBUTES that is different in 32/64bits.
The code I found on Internet also had this bad definition for SECURITY_ATTRIBUTES. But, even after correcting it, the error was still there. I spent several hours trying to fix SECURITY_ATTRIBUTES or anything relate to it.
So, I partially had the answer (wrong definition) but I wasn't looking at the right place. I should have take a step back.
A bad definition (32/64bits) of SECURITY_ATTRIBUTES may result in a access denied with pipe. But, an access denied with pipe when changing platform (32/64bits) may not be relate to a bad SECURITY_ATTRIBUTES definition...
StartupInfo.reserved3 must be an IntPtr. It is a LPBYTE lpReserved2 in the MSDN.
The other pinvokes seems to be correct