Can this be really done without native C code?

[markusschaber]

Hi,
first, I want to thank you for this nice project. However, it looks like it's not really maintained currently.

If it is, I have a question. From reading your code, you just use p/invoke for both the forkpty() and exec() calls. However, this issue comment here states that it's not really safe to use fork() and exec() from native code, as the forked process is in a rather weird state before exec() is called, which is likely to break managed code:

dotnet/runtime#12350 (comment)

So now my question: is that statement in that comment outdated in .NET 8 / .NET 10? (It's from 2019 after all.) Or if not, how do you ensure that the process does not run into these traps? Maybe we actually need native C code here?

Thanks and regards!

[markusschaber]

Just as additional remarks:
The current .NET source uses native code: https://github.com/dotnet/runtime/blob/main/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs#L519

                // Invoke the shim fork/execve routine.  It will create pipes for all requested
                // redirects, fork a child process, map the pipe ends onto the appropriate stdin/stdout/stderr
                // descriptors, and execve to execute the requested process.  The shim implementation
                // is used to fork/execve as executing managed code in a forked process is not safe (only
                // the calling thread will transfer, thread IDs aren't stable across the fork, etc.)
                int errno = Interop.Sys.ForkAndExecProcess(
                    resolvedFilename, argv, envp, cwd,
                    startInfo.RedirectStandardInput, startInfo.RedirectStandardOutput, startInfo.RedirectStandardError,
                    setCredentials, userId, groupId, groups,
                    out childPid, out stdinFd, out stdoutFd, out stderrFd);

Implemented there: https://github.com/dotnet/runtime/blob/main/src/libraries/Common/src/Interop/Unix/System.Native/Interop.ForkAndExecProcess.cs#L28

This may be an alternative: https://github.com/tomlm/Porta.Pty/tree/main/src/Porta.Pty.Native including NuGet Packages.