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.
> +
> + 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
-- PMM
