[PATCH] Cygwin: console: Change timing of set/unset xterm compatible mode.
Takashi Yano
takashi.yano@nifty.ne.jp
Mon Feb 17 10:28:00 GMT 2020
On Mon, 17 Feb 2020 11:16:50 +0100
Corinna Vinschen wrote:
> On Feb 17 18:45, Takashi Yano wrote:
> > On Mon, 17 Feb 2020 10:00:15 +0100
> > Corinna Vinschen wrote:
> > > On Feb 16 17:13, Takashi Yano wrote:
> > > > - If two cygwin programs are executed simultaneousley with pipes
> > > > in cmd.exe, xterm compatible mode is accidentally disabled by
> > > > the process which ends first. After that, escape sequences are
> > > > not handled correctly in the other app. This is the problem 2
> > > > reported in https://cygwin.com/ml/cygwin/2020-02/msg00116.html.
> > > > This patch fixes the issue. This patch also fixes the problem 3.
> > > > For these issues, the timing of setting and unsetting xterm
> > > > compatible mode is changed. For read, xterm compatible mode is
> > > > enabled only within read() or select() functions. For write, it
> > > > is enabled every time write() is called, and restored on close().
> > >
> > > Oh well, I was just going to release 3.1.3 :}
> > >
> > > In terms of this patch, rather than to change the mode on every
> > > invocation of read/write/select/close, wouldn't it make more sense to
> > > count the number of mode switches in a shared per-console variable, i.e.
> > >
> > > LONG shared_console_info::xterms_mode = 0;
> > >
> > > on open:
> > >
> > > if (InterlockedIncrement (&xterm_mode) == 1)
> > > switch to xterm mode;
> > >
> > > on close:
> > >
> > > if (InterlockedDecrement (&xterm_mode)) == 0)
> > > switch back to compat mode;
> > >
> > > ?
> >
> > Thanks for the advice. However this unfortunately does not work
> > in bash->cmd->bash case.
> > For cmd.exe, xterm mode should be disabled, however, the second
> > bash need xterm mode enabled.
> >
> > On Mon, 17 Feb 2020 10:28:19 +0100
> > Corinna Vinschen wrote:
> > > On second thought, also consider that switching the mode and
> > > reading/writing is not atomic. You'd either have to add locking, or you
> > > may suffer the same problem on unfortunate task switching.
> >
> > Hmm, it may be. Let me consider. It may need time, so please
> > go ahead for 3.1.3.
>
> Ok. I just wonder if I should merge your patch into 3.1.3 as is for the
> time being. It's better than the old state, right?
I think so. But I found a small bug in this patch, so please use
v2 patch which I will submit soon.
--
Takashi Yano <takashi.yano@nifty.ne.jp>
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