[CRIU] Re: [PATCH 2/2] tty: Add checkpoint/restore for ttys

[Andrey Wagin]

2012/6/17 Cyrill Gorcunov <gorcunov at openvz.org>:
> On Sun, Jun 17, 2012 at 10:33:31PM +0400, Andrew Vagin wrote:
>> Are you going to restore a controlling terminal?
>> >> The System V approach is that the first tty opened by the process
>> >> becomes its controlling tty.
>> >> The BSD approach is that one has to explicitly call
>> >> ioctl(fd, TIOCSCTTY, ...);
>
> It seems someone replied to this email but it didn't hit c/r
> mailing list? Because I don't see previous conversation here.

It's just quotation.

>
> At moment I've addressed unix98 ttys which have been using
> by 'screen'. The code will be extended once more terminals
> needed.

A controling terminal is a property of sessions.
http://en.wikipedia.org/wiki/POSIX_terminal_interface#Controlling_terminals_and_process_groups


>>
>> Why do we need want_transport()?
>
> Andrew, please, I beg you -- learn (!) to *TRIM( messages and quote
> only the parts you're interesed in.
>
> As to want_transport -- when pty is opened the kernel generates
> slave pty peer by self, but master and slave peer might be in different
> processes. That's what I see with screen -- the master opened in one
> process while slave pty opened in children, and actually it could
> be the reverse. So if I find such situation, the children must wait
> until master opened and connect only when master is ready.

Can a child open a slave point by himself?