[lxc-devel] [PATCH v2] console API improvements

[Serge Hallyn]

Quoting Dwight Engen (dwight.engen at oracle.com):
> Add a higher level console API that opens a tty/console and runs the
> mainloop as well. Rename existing API to console_getfd(). Use these in
> the python binding.
> 
> Allow attaching a console peer after container bootup, including if the
> container was launched with -d. This is made possible by allocation of a
> "proxy" pty as the peer when the console is attached to.
> 
> Improve handling of SIGWINCH, the pty size will be correctly set at the
> beginning of a session and future changes when using the lxc_console() API
> will be propagated to it as well.
> 
> Refactor some common code between lxc_console.c and console.c. The variable
> wait4q (renamed to saw_escape) was static, making the mainloop callback not
> safe across threads. This wasn't a problem when the callback was in the
> non-threaded lxc-console, but now that it is internal to console.c, we have
> to take care of it. This is now contained in a per-tty state structure.
> 
> Don't attempt to open /dev/null as the console peer since /dev/null cannot
> be added to the mainloop (epoll_ctl() fails with EPERM). This isn't needed
> to get the console setup (and the log to work) since the case of not having
> a peer at console init time has to be handled to allow for attaching to it
> later.
> 
> Move signalfd libc wrapper/replacement to utils.h.

Thanks.  Resizing still doesn't work right for me, but it's not like
that's a regression, so I won't wait on that to push this.

(I do want to spend a bit more time reading it in detail)