On Thu, Jan 13, 2022 at 12:28 PM Peter Maydell <peter.mayd...@linaro.org>
wrote:
> On Sun, 9 Jan 2022 at 16:29, Warner Losh <i...@bsdimp.com> wrote:
> >
> > Initialize the signal state for the emulator. Setup a set of sane
> > default signal handlers, mirroring the host's signals. For fatal signals
> > (those that exit by default), establish our own set of signal
> > handlers. Stub out the actual signal handler we use for the moment.
> >
> > Signed-off-by: Stacey Son <s...@freebsd.org>
> > Signed-off-by: Kyle Evans <kev...@freebsd.org>
> > Signed-off-by: Warner Losh <i...@bsdimp.com>
> > ---
> > bsd-user/qemu.h | 1 +
> > bsd-user/signal.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 69 insertions(+)
>
> > +static struct target_sigaction sigact_table[TARGET_NSIG];
>
>
>
>
> > void signal_init(void)
> > {
> > + TaskState *ts = (TaskState *)thread_cpu->opaque;
> > + struct sigaction act;
> > + struct sigaction oact;
> > + int i;
> > + int host_sig;
> > +
> > + /* Set the signal mask from the host mask. */
> > + sigprocmask(0, 0, &ts->signal_mask);
> > +
> > + /*
> > + * Set all host signal handlers. ALL signals are blocked during the
> > + * handlers to serialize them.
> > + */
> > + memset(sigact_table, 0, sizeof(sigact_table));
>
> Do you need this memset()? sigact_table is a global, so it's
> zero-initialized on startup, and this function is only called once.
> The (otherwise basically identical) Linux version of this function
> doesn't have it.
>
Yea, that looks bogus. I'll remove it.
> > +
> > + sigfillset(&act.sa_mask);
> > + act.sa_sigaction = host_signal_handler;
> > + act.sa_flags = SA_SIGINFO;
> > +
> > + for (i = 1; i <= TARGET_NSIG; i++) {
> > + host_sig = target_to_host_signal(i);
> > + sigaction(host_sig, NULL, &oact);
> > + if (oact.sa_sigaction == (void *)SIG_IGN) {
> > + sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN;
> > + } else if (oact.sa_sigaction == (void *)SIG_DFL) {
> > + sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL;
> > + }
> > + /*
> > + * If there's already a handler installed then something has
> > + * gone horribly wrong, so don't even try to handle that case.
> > + * Install some handlers for our own use. We need at least
> > + * SIGSEGV and SIGBUS, to detect exceptions. We can not just
> > + * trap all signals because it affects syscall interrupt
> > + * behavior. But do trap all default-fatal signals.
> > + */
> > + if (fatal_signal(i)) {
> > + sigaction(host_sig, &act, NULL);
> > + }
> > + }
> > }
>
> Otherwise
>
> Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
>
thanks!
Warner
