Re: supporting terminal ownership assignment (tcsetpgrp()) in posix_spawn

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 03/06/2021 10:58, Godmar Back via Libc-help wrote:
> I've recently been playing with posix_spawn() and noticed that it lacks
> support for assigning terminal ownership (as would be done via
> tcsetpgrp()). As a consequence, it cannot be used for job control shells
> when starting jobs in the foreground [1].
> 
> IBM's implementation of spawn [2] for zOS supports SPAWN_SETTCPGRP for this
> reason.
> 
> Even though the POSIX spec states "Future Directions: None" I came across
> this Austin group issue [3] which proposes to add a way to set the child
> process's session id, and which appears to have been accepted in 2016. This
> is an example of evolution of posix_spawn.
> 
> Is anyone aware of efforts to add something similar to POSIX, and more
> specifically, to Linux?
> 
> If the current implementation of posix_spawn is library based (I'm guessing
> it is) then there would be nothing to prevent Linux from adding additional
> flags, just like QNX or Blackberry have already done ([3]).

Other OS might provide a syscall for posix_spawn (I know MacOSX does and
I think maybe Solaris as well), but for Linux is done on top of clone
syscall.

And glibc alread supports POSIX_SPAWN_SETSID since 2.26, so why can't you
use it along with with tcsetpgrp() called from the parent?