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* Re: Can't open display with PuTTY and xinit 1.3.4-1
@ 2015-02-24 16:55 Fj
  2015-02-24 21:00 ` Jon TURNEY
  0 siblings, 1 reply; 5+ messages in thread
From: Fj @ 2015-02-24 16:55 UTC (permalink / raw)
  To: cygwin-xfree

On 2015-01-05 05:31, Laurens Blankers wrote:

> When using PuTTY with X11 forwarding enabled X clients are no longer
able to connect to the X server running locally. When reverting back to
1.3.2-1 the problem goes away.

> This may be related to the -nolisten tcp which is now the default[1]. If
this is indeed the case it would be create of adding the '-listen' flag
to startxwin could be added to the FAQ. Or another, more secure,
solution would also be appreciated.

Hi, I updated Cygwin today and hit the same problem, except even after
I added "-listen tcp" xterm (and gvim) still refused to work
complaining about "No protocol specified" (before was: "Can't open
display").

Putty logs say "Opening X11 forward connection succeeded" (before
"-listen tcp" it was: "Forwarded X11 connection terminated due to
local error"), which seems to indicate that the problem is with the X
server (and the way xterm/gvim communicate with it).

Ssh-ing to the server from Cygwin terminal works and I can even launch
gvim from the Putty's tty by specifying the same DISPLAY the Cygwin
connection provides.

After reverting to some early 2014 version of xinit and xorg (thank
god for Cygwin Time Machine) everything resumed working properly.

(on a side note, I tried to figure out what are the possible "-listen"
options by looking at the xserver code, there are three, "tcp",
"unix", "local". What does "local" mean, couldn't it be loopback
adapter? Where is "_XSERVTransNoListen" function implemented?)

--

Fj.

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Can't open display with PuTTY and xinit 1.3.4-1
  2015-02-24 16:55 Can't open display with PuTTY and xinit 1.3.4-1 Fj
@ 2015-02-24 21:00 ` Jon TURNEY
  0 siblings, 0 replies; 5+ messages in thread
From: Jon TURNEY @ 2015-02-24 21:00 UTC (permalink / raw)
  To: cygwin-xfree; +Cc: fj.mail

On 24/02/2015 16:55, Fj wrote:
> On 2015-01-05 05:31, Laurens Blankers wrote:
>> When using PuTTY with X11 forwarding enabled X clients are no longer
> able to connect to the X server running locally. When reverting back to
> 1.3.2-1 the problem goes away.
>
>> This may be related to the -nolisten tcp which is now the default[1]. If
> this is indeed the case it would be create of adding the '-listen' flag
> to startxwin could be added to the FAQ. Or another, more secure,
> solution would also be appreciated.
>
> Hi, I updated Cygwin today and hit the same problem, except even after
> I added "-listen tcp" xterm (and gvim) still refused to work
> complaining about "No protocol specified" (before was: "Can't open
> display").

The "No protocol specified" message is a bit obtuse.

It comes back from the server when an attempt is made to open a 
connection, and really means something like "Authorization required, but 
no authorization protocol specified" - the server was started with an 
authorization file using the -auth option, but the client didn't offer 
any authorization data.

> Putty logs say "Opening X11 forward connection succeeded" (before
> "-listen tcp" it was: "Forwarded X11 connection terminated due to
> local error"), which seems to indicate that the problem is with the X
> server (and the way xterm/gvim communicate with it).

I'm afraid it seems '-listen tcp' is not enough for PuTTY to 
successfully connect.

If the server was started with -auth (which startxwin does since 
xinit-1.3.4-1), then PuTTY will need authorization data to successfully 
connect.

Whilst you can do this by setting the "X authority file for local 
display" in PuTTY's configuration to the Windows path equivalent to 
~/.serverauth.NNNN, this isn't much of a solution as this filename 
changes everytime the server is started.

Perhaps xinit needs an option to avoid using -auth? One can demonstrate 
that works by starting the server directly, e.g. using 'XWin 
-multiwindow -listen tcp' rather than 'startxwin'.

Definitely some sort of change is needed to make this work better.

> Ssh-ing to the server from Cygwin terminal works and I can even launch
> gvim from the Putty's tty by specifying the same DISPLAY the Cygwin
> connection provides.
>
> After reverting to some early 2014 version of xinit and xorg (thank
> god for Cygwin Time Machine) everything resumed working properly.
>
> (on a side note, I tried to figure out what are the possible "-listen"
> options by looking at the xserver code, there are three, "tcp",
> "unix", "local". What does "local" mean, couldn't it be loopback
> adapter? Where is "_XSERVTransNoListen" function implemented?)

I think "local" is an alias for "unix", which uses a UNIX domain socket 
(as emulated by cygwin)

_XSERVTransNoListen is implemented (via some macros) in libXtrans.

-- 
Jon TURNEY
Volunteer Cygwin/X X Server maintainer

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Can't open display with PuTTY and xinit 1.3.4-1
  2015-01-05 17:31 ` Yaakov Selkowitz
@ 2015-01-06  9:12   ` Laurens Blankers
  0 siblings, 0 replies; 5+ messages in thread
From: Laurens Blankers @ 2015-01-06  9:12 UTC (permalink / raw)
  To: cygwin-xfree

On 5-1-2015 18:31, Yaakov Selkowitz wrote:
> Wait, are you talking about a Windows version of PuTTY? 
There is a PuTTY for *nix? And it has been ported to Cygwin? I didn't
know. That is, let's say, amazing :-) Yes I mean the native PuTTY for
Windows.

> This will be added to the FAQ in due course.
Thank you.

> BTW, reverting this behaviour isn't an option either, as it will
> actually become the upstream default in the next major release of the
> X server.
I am perfectly fine with keeping this behaviour since it is more secure,
especially if it becomes the default. An entry in the FAQ is perfect.

-- 
Laurens

_____________________________________________________________________
A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting annoying in email?


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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Can't open display with PuTTY and xinit 1.3.4-1
  2015-01-05 11:32 Laurens Blankers
@ 2015-01-05 17:31 ` Yaakov Selkowitz
  2015-01-06  9:12   ` Laurens Blankers
  0 siblings, 1 reply; 5+ messages in thread
From: Yaakov Selkowitz @ 2015-01-05 17:31 UTC (permalink / raw)
  To: cygwin-xfree

On 2015-01-05 05:31, Laurens Blankers wrote:
> When using PuTTY with X11 forwarding enabled X clients are no longer
> able to connect to the X server running locally. When reverting back to
> 1.3.2-1 the problem goes away.
>
> This may be related to the -nolisten tcp which is now the default[1]. If
> this is indeed the case it would be create of adding the '-listen' flag
> to startxwin could be added to the FAQ. Or another, more secure,
> solution would also be appreciated.

Wait, are you talking about a Windows version of PuTTY?  Then that makes 
sense, as it would be unable of using the *NIX socket typically used by 
local X clients, and I am indeed able to duplicate that behaviour.  I 
can't think of an alternative to -listen if you wish to use a Windows 
PuTTY (or, for that matter, any MinGW-compiled X client) with Cygwin/X. 
  This will be added to the FAQ in due course.

However, a Cygwin PuTTY does not have that limitation, and X11 
forwarding works just fine as is.  (If there is interest, I can easily 
add this to the distribution.)  Similarly, the Cygwin (open)ssh 
obviously has no problems with X11 forwarding either.

BTW, reverting this behaviour isn't an option either, as it will 
actually become the upstream default in the next major release of the X 
server.

HTH,

Yaakov


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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Can't open display with PuTTY and xinit 1.3.4-1
@ 2015-01-05 11:32 Laurens Blankers
  2015-01-05 17:31 ` Yaakov Selkowitz
  0 siblings, 1 reply; 5+ messages in thread
From: Laurens Blankers @ 2015-01-05 11:32 UTC (permalink / raw)
  To: cygwin-xfree

When using PuTTY with X11 forwarding enabled X clients are no longer
able to connect to the X server running locally. When reverting back to
1.3.2-1 the problem goes away.

This may be related to the -nolisten tcp which is now the default[1]. If
this is indeed the case it would be create of adding the '-listen' flag
to startxwin could be added to the FAQ. Or another, more secure,
solution would also be appreciated.

[1] https://cygwin.com/ml/cygwin-xfree/2014-12/msg00024.html

Laurens

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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2015-02-24 19:32 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2015-02-24 16:55 Can't open display with PuTTY and xinit 1.3.4-1 Fj
2015-02-24 21:00 ` Jon TURNEY
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2015-01-05 11:32 Laurens Blankers
2015-01-05 17:31 ` Yaakov Selkowitz
2015-01-06  9:12   ` Laurens Blankers

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