[CRIU] Re: [PATCH 5/5] tty: Add restoration of controlling terminal v2

[Pavel Emelyanov]

On 09/12/2012 10:58 AM, Cyrill Gorcunov wrote:
> 
> The idea behind is pretty simple -- once we find
> that there is a controlling terminal present we
> do call ioctl on appropriate /dev/pts/N.
> 
> v2:
>  - restore control terminals via service fd,
>    still need to speedup service fd retrieval.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  cr-restore.c      |    2 +-
>  files.c           |   27 ++++++++++++++++++-
>  include/crtools.h |    1 +
>  include/files.h   |    2 +-
>  include/pstree.h  |    1 +
>  include/tty.h     |    1 +
>  tty.c             |   75 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  7 files changed, 106 insertions(+), 3 deletions(-)
> 

> @@ -517,6 +560,15 @@ static int tty_open(struct file_desc *d)
>  
>  }
>  
> +int tty_restore_ctl_terminal(struct file_desc *d)
> +{
> +	struct tty_info *info = container_of(d, struct tty_info, d);
> +
> +	BUG_ON(!(pty_is_master(info)) || !info->tie->sid);

This equals to BUG_ON(!is_master && info->sid). Why non master must NOT have sids?

> +
> +	return __tty_restore_ctl_terminal(info);
> +}
> +
>  static int tty_transport(FdinfoEntry *fe, struct file_desc *d)
>  {
>  	struct tty_info *info = container_of(d, struct tty_info, d);

> @@ -387,6 +400,12 @@ static int open_fd(int pid, FdinfoEntry *fe, struct file_desc *d)
>  				return -1;
>  			}
>  
> +			if (fle->fe->fd == get_service_fd(CTL_TTY_OFF)) {
> +				tty_restore_ctl_terminal(d);
> +				close(fle->fe->fd);
> +				continue;
> +			}
> +
>  			fcntl(fle->fe->fd, F_SETFD, fle->fe->flags);
>  
>  			continue;
> @@ -424,6 +443,12 @@ static int receive_fd(int pid, FdinfoEntry *fe, struct file_desc *d)
>  	if (reopen_fd_as(fe->fd, tmp) < 0)
>  		return -1;
>  
> +	if (fe->fd == get_service_fd(CTL_TTY_OFF)) {
> +		tty_restore_ctl_terminal(d);
> +		close(fle->fe->fd);
> +		return 0;
> +	}
> +
>  	fcntl(tmp, F_SETFD, fe->flags);
>  	return 0;
>  }

Why not in post_open?

> @@ -131,7 +131,7 @@ static int prepare_shared(void)
>  		if (ret < 0)
>  			break;
>  
> -		ret = prepare_fd_pid(pi->pid.virt, pi->rst);
> +		ret = prepare_fd_pid(pi->pid.virt, pi->rst, pi->ctl_tty_id);
>  		if (ret < 0)
>  			break;
>  	}

Better introduce prepare_ctl_tty() call.