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Message-ID: <8F23E55D511AD5119A6800D0B76FDDE11E102E@cpex3.channelpoint.com>
From: Troy Noble <troy DOT noble AT channelpoint DOT com>
To: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: RE: Brainstorming a fix for CTRL-C handling in an emacs shell buf
	 fer (non-TTY)
Date: Wed, 9 May 2001 09:03:20 -0600 
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I am using unmodified bash-2.05.0-5 from the cygnus-latest, and
a cygwin1.dll that I built from the CVS sources that I checked
out fresh ("cvs co" as opposed to "cvs update") right after
your last patch to exceptions.cc.

The only winsup/cygwin modification I had in place at the time
was the printf in the ctrl_c_handler so I could see what was
going on there.

I looked at the bash sources some last night, and it seems to me
that since bash thinks it is running in a pipe (stdin is a pipe
after all), I think it's never passing control of the tty on
to the child.  There are some comments in jobs.c:make_child to
that effect.

That would explain why t->getpgid() != myself->pid.

Does not explain why bash isn't SIGTERM-ing its children as you
suspect might be happening.

Here's the minimal test case I have come up with that you can try
there without installing emacs.  You'll need to add the printf to
ctrl_c_handler to get the same type of output.  Then start a
cmd.exe window and do the following:

C:\work\build\src\winsup\cygwin>cat /tmp/tmp.sh
sleep 10
    <press CTRL-C>
C:\work\build\src\winsup\cygwin>bash </tmp/tmp.sh
GetConsoleCP=437 isatty=0 pid_exists=1 t->getsid()=680 t->getpgid()=680
    myself->pid=1388 pgid=680 ppid=680 sid=680
progname=c:\cygwin\bin\sleep.exe
GetConsoleCP=437 isatty=0 pid_exists=1 t->getsid()=680 t->getpgid()=680
    myself->pid=680 pgid=680 ppid=1 sid=680 progname=c:\cygwin\bin\bash.exe

C:\work\build\src\winsup\cygwin>bash
% sleep 10
    <press CTRL-C>
GetConsoleCP=437 isatty=1 pid_exists=1 t->getsid()=1400 t->getpgid()=288
    myself->pid=288 pgid=288 ppid=1400 sid=1400
progname=c:\cygwin\bin\sleep.exe

GetConsoleCP=437 isatty=1 pid_exists=1 t->getsid()=1400 t->getpgid()=288
    myself->pid=1400 pgid=1400 ppid=1 sid=1400
progname=c:\cygwin\bin\bash.exe

Troy

-----Original Message-----
From: Christopher Faylor [mailto:cgf AT redhat DOT com]
Sent: Tuesday, May 08, 2001 5:59 PM
To: 'cygwin AT cygwin DOT com'
Subject: Re: Brainstorming a fix for CTRL-C handling in an emacs shell
buf fer (non-TTY)


On Tue, May 08, 2001 at 05:46:05PM -0600, Troy Noble wrote:
>Looks like a I caught a break this time.
>
>I can't tell if we're converging on a solution at this point or
>diverging.  However, I did want to get you some usable strace
>output if possible.

This is a symptom of things working, though.  I'm trying to get an
strace of a failing situation.

>Let me know if I've worn out my welcome or if you want me to
>move to the developer list to cut down the traffic on this list.
>
>I started bash in an emacs buffer, then ran "strace bash",
>then ran my "ls -lR".  Then pressed CTRL-C.
>
>If I read the strace output correctly,
>it looks like bash figures out that it has a child process,
>and I can see the child process responding to the SIGINT signal.

I don't see bash sending a SIGINT.

>The "ls" process ctrl_c_handler never gets invoked, which is
>good.  So I'm 99% sure that ls shut down in response to bash's
>signal.  Bash then detects that the child exited and removes
>it from its table of child processes.

It does receive a SIGINT and die but I don't know why.  Are you
working with a pure Cygwin from CVS?

cgf

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