Re: [PATCH RFA] Linux threads, SIGINT handling

[Michael Snyder <msnyder at cygnus dot com>]

Mark Kettenis wrote:
> 
>    Date: Fri, 25 May 2001 12:18:37 -0700
>    From: Michael Snyder <msnyder@cygnus.com>
> 
>    Mark,
> 
>    When a user types ^C(break) at a tty on Linux, SIGINT is sent to every
>    thread in the process group (whether by the kernel or by the manager
>    thread, I do not know).  The effect is that, if you type ^C once, you
>    have to say "continue" N times (once for every user thread).
> 
> It's the kernel that sends all those SIGINTs, since to the kernel our
> program is just a bunch of processes sharing their VM.  And indeed,
> the effect is rather annoying.
> 
>    This patch handles that problem by discarding the redundant SIGINT
>    events (ie. all of them except the one that was actually detected in
>    lin_lwp_wait).
> 
> I don't think it's OK to unconditionally discard the SIGINT events.
> The process might want to do something special with those, and may
> depend on getting them in every thread.  How about changing the
> 
>    else if (WSTOPSIG (status) == SIGINT)
> 
> into
> 
>    else if (WSTOPSIG (status) == SIGINT
>             && signal_pass_state (SIGINT) == 0)
> 
> ?  Not passing SIGINT to the inferior is GDB's default, so this will
> work fine for most people.  And this way people can say
> 
>    "handle SIGINT pass"
> 
> ignore the warning, and have SIGINT delivered to all threads.
> 
> If you agree, it's OK to check this in with that change.

Agreed and committed.

Michael