Re: Pseudo console support in PTY

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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Hi Takashi,

On Mar 30 22:08, Takashi Yano wrote:
> Hello cygwin developers,
> 
> I have worked on implementing pseudo console support into cygwin
> PTY by request from Corinna. Pseudo console is a new feature
> after Windows 10 1809, which provides console APIs on virtual
> terminal.
> https://blogs.msdn.microsoft.com/commandline/2018/08/02/windows-command-line-introducing-the-windows-pseudo-console-conpty/
> https://docs.microsoft.com/en-us/windows/console/creating-a-pseudoconsole-session
> 
> After much effort, it began to work partially. So, I would
> like to announce to this mailing list. Attached are the
> patchs against cygwin git HEAD.

\o/

Thanks a lot for doing this!

> Patch 0001 and 0002 are not really needed by the pseudo console
> support, but are the modification I have done at the same time.
> 
> Patch 0001: This just renames and unifies the function names.
>   Both get_io_handle() and get_handle() were identical and
>   returned io_handle. So, they were unified.

This one is ok to be pushed to master as is.

> Patch 0002: This revises console code for better color handling
>   and fixing select() behaviour. This provides 24 bit color
>   support after Windows 10 build 14931. For legacy console,
>   fake 256 color support is implemented, which use the nearest
>   color from 16 system colors.

This patch is certainly a nice addition, but I'd prefer this to be split
into a patchset of at least 3 separate patches:

- Fix select

- Make console thread-safe

- Color code changes

These are three very different changes which should all stand on their
own.  This also improves looking for bugs.

> Patch 0003: Support pseudo console in PTY. With this patch,
>   native console applications can work in PTY such as mintty,
>   ssh, gnu screen or tmux.

This patch is missing a bit of commenting.  There are a couple of #if
0/1 blocks.  It would be nice to know what these are good for (and
ultimately the #if 0/1's should go away).  It would alos be helpful
if you see a chance to split this into a patchset with a few
self-contained, co-ordinated patches.

Apart from patch 1, which I'll push in a minute, please send any
patch submissions to cygwin-patches.

Thanks a lot for working on this.  If all goes well we could even push
this into 3.1, together with Ken's FIFO patches.

This is all pretty exciting.

> Anyone who are interested in this work, please test. Any
> discussions and suggestions are also welcome.
> 
> You can download the binaries from:

Already running your patches with self-built cygwin DLL and
cygwin-console-helper ;)

It seems the mintty startup is a bit slower than before, but
personally I could live with that.

> D=http://tyan0.dip.jp/cygwin
> ${D}/x86_64/test/cygwin1-20190330.dll.xz
> ${D}/x86_64/test/cygwin-console-helper.exe.xz
> ${D}/x86/test/cygwin1-20190330.dll.xz
> ${D}/x86/test/cygwin-console-helper.exe.xz
> 
> This cygwin1.dll requires new cygwin-console-helper.exe.
> Please unxz and put them into /bin directory.
> 
> Known problems:
> * Sometimes the screen layout would be broken.
> * mintty fails to start if it is started in console cygwin
>   session.

Good to know, thanks!


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer

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