From: Andrew Cagney <cagney@redhat.com>
To: Mark Wielaard <mark@klomp.org>
Cc: frysk@sourceware.org, npremji@sourceware.org
Subject: Re: frysk-core/frysk/proc LinuxTask.java TestProcS ...
Date: Wed, 11 Oct 2006 22:33:00 -0000 [thread overview]
Message-ID: <452D7143.6050804@redhat.com> (raw)
In-Reply-To: <1160601989.3025.25.camel@dijkstra.wildebeest.org>
Mark Wielaard wrote:
> Aha. So we are trying to trick our own waitpid() into thinking it
> received a new SIGCHLD event? But aren't we actually waiting for a
> SIGSTOP from the child after an ptrace attach?
>
>
A waitpid doesn not receive a SIGCHLD event, rather the arrival of a
waitpid event normally leads to the controlling process being sent a
SIGCHLD.
Nurden's patch, which is simple and elegant, fudges the case of SIGCHLD
not being sent by sending one anyway.
Andrew
> Is sending the signal to our calling Thread as good as sending to any
> other Thread in our frysk process? I am slightly surprised that the
> signal arrives in a way that waitpid() is detecting it, since this isn't
> a real SIGCHLD/SIGSTOP signal from the task we want to attach to. How
> precisely does this work?
>
> Cheers,
>
> Mark
>
>
next prev parent reply other threads:[~2006-10-11 22:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20061011195727.26918.qmail@sourceware.org>
2006-10-11 20:13 ` Mark Wielaard
2006-10-11 20:57 ` Andrew Cagney
2006-10-11 21:26 ` Mark Wielaard
2006-10-11 21:39 ` Nurdin Premji
2006-10-11 22:33 ` Andrew Cagney [this message]
2006-10-12 9:17 ` Mark Wielaard
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