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Re: [Qemu-devel] [PATCH] linux-user: Proper exit code for uncaught signa
From: |
Riku Voipio |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: Proper exit code for uncaught signals |
Date: |
Thu, 27 Nov 2008 14:21:44 +0200 |
User-agent: |
Mutt/1.5.11+cvs20060126 |
On Thu, Nov 27, 2008 at 12:42:33PM +0100, Thiemo Seufer wrote:
> Riku Voipio wrote:
> > The proper exit code for dieing from an uncaught signal is -<signal>.
> > The kernel doesn't allow exit() or _exit() to pass a negative value.
> > To get the proper exit code we need to actually die from an uncaught
> > signal.
> >
> > A default signal handler is installed, we send ourself a signal
> > and we wait for it to arrive.
> >
> > Patch originates from Scratchbox
>
> So, who holds the copyright (and deserves the credit)?
The qemu tarball[1] provided on scratchbox site doesn't
document who wrote patches and who has the copyright. Most
likely a contractor for Nokia wrote it, and the copyright is
Nokia's.
Lauro might know as the patch is also at the qemu-arm-eabi
sf project site.
[1]
http://scratchbox.org/download/files/sbox-releases/stable/src/scratchbox-devkit-cputransp-qemu-arm-cvs-m-1.0.7/qemu-arm-0108.tar.gz
> Thiemo
>
> > Signed-off-by: Riku Voipio <address@hidden>
> > ---
> > linux-user/signal.c | 37 +++++++++++++++++++++++++------------
> > 1 files changed, 25 insertions(+), 12 deletions(-)
> >
> > diff --git a/linux-user/signal.c b/linux-user/signal.c
> > index e0f6aaf..dac9933 100644
> > --- a/linux-user/signal.c
> > +++ b/linux-user/signal.c
> > @@ -24,6 +24,7 @@
> > #include <unistd.h>
> > #include <signal.h>
> > #include <errno.h>
> > +#include <assert.h>
> > #include <sys/ucontext.h>
> >
> > #include "qemu.h"
> > @@ -328,21 +329,33 @@ static inline void free_sigqueue(CPUState *env,
> > struct sigqueue *q)
> > static void __attribute((noreturn)) force_sig(int sig)
> > {
> > int host_sig;
> > + struct sigaction act;
> > host_sig = target_to_host_signal(sig);
> > fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
> > sig, strsignal(host_sig));
> > -#if 1
> > - _exit(-host_sig);
> > -#else
> > - {
> > - struct sigaction act;
> > - sigemptyset(&act.sa_mask);
> > - act.sa_flags = SA_SIGINFO;
> > - act.sa_sigaction = SIG_DFL;
> > - sigaction(SIGABRT, &act, NULL);
> > - abort();
> > - }
> > -#endif
> > +
> > + /* The proper exit code for dieing from an uncaught signal is
> > + * -<signal>. The kernel doesn't allow exit() or _exit() to pass
> > + * a negative value. To get the proper exit code we need to
> > + * actually die from an uncaught signal. Here the default signal
> > + * handler is installed, we send ourself a signal and we wait for
> > + * it to arrive. */
> > + sigfillset(&act.sa_mask);
> > + act.sa_handler = SIG_DFL;
> > + sigaction(host_sig, &act, NULL);
> > +
> > + /* For some reason raise(host_sig) doesn't send the signal when
> > + * statically linked on x86-64. */
> > + kill(getpid(), host_sig);
> > +
> > + /* Make sure the signal isn't masked (just reuse the mask inside
> > + of act) */
> > + sigdelset(&act.sa_mask, host_sig);
> > + sigsuspend(&act.sa_mask);
> > +
> > + /* unreachable */
> > + assert(0);
> > +
> > }
> >
> > /* queue a signal so that it will be send to the virtual CPU as soon
> > --
> > 1.5.6.5
> >
> >
> > --
> > "rm -rf" only sounds scary if you don't have backups
> >
--
"rm -rf" only sounds scary if you don't have backups