stty -cooked not usable since cygwin-3.1.1-1

[Rabbe Fogelholm]

On 2020-07-28 18:56, Thomas Wolff wrote:
> 
> 
> Am 28.07.2020 um 18:38 schrieb Takashi Yano via Cygwin:
>> On Tue, 28 Jul 2020 15:56:54 +0200
>> Rabbe Fogelholm wrote:
>>> Rabbe Fogelholm wrote:
>>>> Takashi Yano wrote:
>>>>> On Mon, 13 Jan 2020 11:52:43 +0100
>>>>> Rabbe Fogelholm wrote:
>>>>>> I am running a console Java program that is started from a 
>>>>>> shellscript
>>>>>> wrapper. Before invoking Java the wrapper calls `stty -cooked'. 
>>>>>> The Java
>>>>>> program polls the keyboard using System.in.available() and reads
>>>>>> characters immediately using System.in.read(), without waiting for 
>>>>>> the
>>>>>> Enter key to be pressed.
>>>>>>
>>>>>> This way of combining `stty -cooked' and Java has stopped working 
>>>>>> since
>>>>>> version 3.1.1-1 of the Cygwin package. The Java thread that reads the
>>>>>> keyboard hangs until Enter is pressed, which is not desirable.
>>>>>>
>>>>>> I had to downgrade to version 3.0.7-1 to resolve the problem.
>>>>>>
>>>>>> Versioning information:
>>>>>>
>>>>>> java version "1.8.0_202"
>>>>>> Java(TM) SE Runtime Environment (build 1.8.0_202-b08)
>>>>>> Java HotSpot(TM) 64-Bit Server VM (build 25.202-b08, mixed mode)
>>>>>>
>>>>>> OS Name: Microsoft Windows 10 Pro
>>>>>> Version: 10.0.17763 Build 17763
>>>>>> System Type: x64-based PC
>>>>>>
>>>>>> See also the enclosed cygcheck.out.
>>>>>>
>>>>>> To demonstrate the issue I enclose a small Java program that 
>>>>>> should be
>>>>>> able to read single keystrokes when `stty -cooked' is in effect.
>>>>> Does your java program work in command prompt? cygwin 3.1.x uses
>>>>> pseudo console, so the native (non cygwin) program works as if it
>>>>> is executed in command prompt.
>>>>>
>>>> With cygwin 3.1.x I can't find a way to make my program work.
>>>>
>>>> When running from within a Cygwin64 terminal the `stty -cooked' command
>>>> terminates with exit code 0, but the Java program behaves just as if
>>>> `stty -cooked' is not in effect: It does not handle single keystrokes
>>>> immediately.
>>>>
>>>> When running from a Windows command prompt I can execute the stty
>>>> program as \cygwin64\bin\stty. However, when given the '-cooked'
>>>> argument it complains:
>>>> /usr/bin/stty: 'standard input': unable to perform all requested 
>>>> operations
>>>>
>>>> - and here as well the Java program behaves as if `stty -cooked' is not
>>>> in effect.
>>> Some time has passed; I am just curious if anyone may have found a
>>> solution to the "stty -cooked" issue. With cygwin-3.0.* it was possible
>>> to have a Java program act on single keystrokes, with cygwin-3.1 I don't
>>> know how to do it. Any ideas welcome!
>> Solution 1:
>> Redesign your java program using JNA with kbhit()/getch() instead of
>> System.in.available()/System.in.read().
>>
>> Solution 2:
>> Add SetConsoleMode() call with ENABLE_LINE_INPUT flag cleared using JNA.
> Couldn't cygwin clear this flag when it sets up ConPTY while the pty is 
> in raw mode?
> Thomas
> 
>>
>> Solution 3:
>> Use a wrappwer instead of stty such as:
>>
>> #include <stdio.h>
>> #include <unistd.h>
>> #include <termios.h>
>> #include <string.h>
>> #include <pthread.h>
>> #include <sys/wait.h>
>>
>> void *fwd(void *param)
>> {
>>      FILE *f = (FILE *) param;
>>      char buf[128];
>>      int len;
>>      while (1) {
>>          if ((len = read(0, buf, sizeof(buf))) <= 0) break;
>>          if (write(fileno(f), buf, len) < len) break;
>>      }
>>      return NULL;
>> }
>>
>> int main(int argc, char *argv[])
>> {
>>      FILE *f;
>>      int i;
>>      pthread_t th;
>>      struct termios t, t_orig;
>>      char cmd[1024] = {0, };
>>      if (argc < 2) return 0;
>>      for (i = 1; i < argc && strlen(cmd)+strlen(argv[i]) < 
>> sizeof(cmd)-2; i++) {
>>          sprintf(cmd + strlen(cmd), (i>1)?" %s":"%s", argv[i]);
>>      }
>>      f = popen(cmd, "w");
>>      tcgetattr(0, &t_orig);
>>      t = t_orig;
>>      cfmakeraw(&t);
>>      tcsetattr(0, TCSANOW, &t);
>>      pthread_create(&th, NULL, fwd, f);
>>      wait(NULL);
>>      tcsetattr(0, TCSANOW, &t_orig);
>>      pclose(f);
>>      return 0;
>> }
>>
> 
> 
Thanks Takashi for suggesting many ways to solve this! The C wrapper
solution looks quite powerful.

Meanwhile it has occurred to me that bash itself can provide a
workaround. Since I start the Java console application from a bash
wrapper already, I have now changed it so that it does something like
this:

(while true; do read -s -r -N 1 Key; echo "$Key"; done) | java ...

With these options to 'read' I get action on every keystroke, and the
Java program gets its input as terminated length-1 lines.