Re: New implementation of pseudo console support (experimental)

[Takashi Yano <takashi.yano@nifty.ne.jp>]

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Hi Thomas,

On Sat, 18 Jul 2020 22:57:24 +0200
Thomas Wolff wrote:
> Am 18.07.2020 um 07:05 schrieb Takashi Yano via Cygwin-developers:
> > Hi Thomas,
> >
> > Thanks for testing.
> >
> > On Fri, 17 Jul 2020 16:59:56 +0200
> > Thomas Wolff wrote:
> >> Am 17.07.2020 um 14:47 schrieb Thomas Wolff:
> >>> Am 17.07.2020 um 13:19 schrieb Corinna Vinschen:
> >>>> Hi Takashi,
> >>>>
> >>>> On Jul  1 20:47, Takashi Yano via Cygwin-developers wrote:
> >>>>> On Fri, 29 May 2020 00:40:24 +0900
> >>>>> Takashi Yano via Cygwin-developers <cygwin-developers@cygwin.com>
> >>>>> wrote:
> >>>>>> On Tue, 26 May 2020 10:09:55 +0900
> >>>>>> Takashi Yano via Cygwin-developers <cygwin-developers@cygwin.com>
> >>>>>> wrote:
> >>>>>>> On Mon, 25 May 2020 19:53:32 +0900
> >>>>>>> Takashi Yano via Cygwin-developers <cygwin-developers@cygwin.com>
> >>>>>>> wrote:
> >>>>>>>> On Tue, 19 May 2020 22:40:18 +0900
> >>>>>>>> Takashi Yano via Cygwin-developers <cygwin-developers@cygwin.com>
> >>>>>>>> wrote:
> >>>>>>>>> On Sat, 16 May 2020 16:47:35 +0900
> >>>>>>>>> Takashi Yano via Cygwin-developers
> >>>>>>>>> <cygwin-developers@cygwin.com> wrote:
> >>>>>>>>>> On Sat, 16 May 2020 09:29:56 +0900
> >>>>>>>>>> Takashi Yano via Cygwin-developers
> >>>>>>>>>> <cygwin-developers@cygwin.com> wrote:
> >>>>>>>>>>> Fix a small bug caused when stdio is redirected to another pty.
> >>>>>>>>>> Fix another bug caused when stdio is redirected to another pty.
> >>>>>>>>> Revise the patch to fit the current git head.
> >>>>>>>> Revise the patch again to fit the current git head.
> >>>>>>> Make app, which reads stdin, work under gdb.
> >>>>>> * Prevent ResizePseudoConsole() calls unless the pty is resized.
> >>>>>> * Revise the patch to fit the current git head.
> >>>>> Revise the patch to fit the current git head.
> >>>> are you satisfied with the code?  If you want to merge it,
> >>>> I'd bump Cygwin to 3.2.
> >>> (blush) I apologize, I had promised to run my test cases.
> >>> Beginning with it, the first succeeded, the second failed:
> >>> run notepad (from mintty), click back into terminal, enter ^Z
> >>> It says "Stopped" but the process is gone.
> >>>
> >>> Continuing may test suite soon...
> >> OK, so here are finally my updated test results:
> >>
> >>
> >> resize terminal while running Windows cmd
> >> run cmd, resize, run dir/P:
> >> ✓works
> >>
> >>
> >> terminal reports in response to request escape sequences
> >> ("\033[6n", "\033[0c", "\033[>c", '\033[18t', '\033]10;?\033\')
> >> ✓works
> >>
> >>
> >> output to alternate screen
> >> echo -e "\e[?1047h"; cmd
> >> ✓works
> >> cmd
> >> from other terminal: echo -e "\e[?1047h" > /dev/pty...
> >> ↯no output; weird behaviour on ^C, mintty terminating (also in 3.1.6)
> > I found this is a bug introduced in commit
> > 0365031ce1347600d854a23f30f1355745a1765c.
> >
> > I will submit a patch for this issue.
> >
> >> signal handling/mediation; catch SIGTSTP
> >> run notepad, click back into terminal, enter ^Z
> >> ↯fails, notepad is terminated
> >> -> this is a regression, ^Z,^C,^\ used to be ignored
> > This behaviour is the same as cygwin 3.0.7. Pseudo console is not
> > activated for native GUI processes.
> OK, I understand this is consistent with my own proposal to apply pseudo 
> console only for Windows command-line programs. On the other hand, fatal 
> signal handling is another nuisance of running Windows programs from 
> cygwin, so there was a benefit.
> Is it possible to activate the signal interworking without setting up a 
> pseudo console? If not, is it maybe worth to set it up also for Windows 
> GUI programs just for this purpose? (Modifying my proposal to trigger on 
> any Windows program.)

When pseudo console is activated for GUI apps, ^C, ^Z and ^\ are
just ignored. Please try additional patch attached with the latest
pseudo console patch. Is this as you expected?

I'm not sure which behaviour is better. Does anyone have opinion?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>

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diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index a3071884e..4524423b3 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -194,24 +194,6 @@ handle (int fd, bool writing)
   return h;
 }
 
-static bool
-is_console_app (WCHAR *filename)
-{
-  HANDLE h;
-  const int id_offset = 92;
-  h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,
-		  NULL, OPEN_EXISTING, 0, NULL);
-  char buf[1024];
-  DWORD n;
-  ReadFile (h, buf, sizeof (buf), &n, 0);
-  CloseHandle (h);
-  char *p = (char *) memmem (buf, n, "PE\0\0", 4);
-  if (p && p + id_offset <= buf + n)
-    return p[id_offset] == '\003'; /* 02: GUI, 03: console */
-  else
-    return false;
-}
-
 int
 iscmd (const char *argv0, const char *what)
 {
@@ -632,7 +614,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
       STARTUPINFOEXW si_pcon;
       ZeroMemory (&si_pcon, sizeof (si_pcon));
       STARTUPINFOW *si_tmp = &si;
-      if (!iscygwin () && ptys_primary && is_console_app (runpath))
+      if (!iscygwin () && ptys_primary)
 	if (ptys_primary->setup_pseudoconsole (&si_pcon))
 	  {
 	    c_flags |= EXTENDED_STARTUPINFO_PRESENT;