[Devel] [PATCH rh7 0/3] Zap Unix98 pty virtualization

[Cyrill Gorcunov]

On Thu, Jul 23, 2015 at 06:54:34PM +0300, Vladimir Davydov wrote:
> Dunno why it was done in the first place - Unix98 ptys are already
> virtualized on the VFS layer, nothing needs to be done on the driver's
> side. We don't even have this in PCS6.
> 
> Vladimir Davydov (3):
>   Revert "ve/pty: containerize Unix98 pty drivers"
>   Revert "ve/pty: containerize Unix98 driver"
>   Revert "pty: split Unix98 init routines"

This series ruins my vt virtual driver. But what is worse
it kills bsd terminals (legacy one).

Letme explain. The tty drivers may carry predefined number
of tty structures (in other terms than named @lines) it
is a number of terminals driver may carry opened at once.

struct tty_driver {
	...
	struct tty_struct **ttys;
	...
}

Bsd terminals (@master_pty_ops_bsd) uses this facility
in a very heavy way -- when one peer is about to open/
close, the appropriate element inside tty_driver::ttys[index]
either assigned to allocated tty structure or dropped to nil.
So if we revert it one caontainer can open bsd terminal
while another container simply close it, or reuse ;)

I would rather suggest to dive into tty layer itself
and virtualize @ttys, @ports, @termios. If we drop
virt code I will have to rework my vt driver anyway
for exatly same reason so I can try address this
problem as well but not sure if I manage before Beta1.