On Sun, 9 Jan 2022 at 16:47, Warner Losh <i...@bsdimp.com> wrote:
>
> Handle a queued signal.
>
> Signed-off-by: Stacey Son <s...@freebsd.org>
> Signed-off-by: Kyle Evans <kev...@freebsd.org>
> Signed-off-by: Warner Losh <i...@bsdimp.com>
> +static void handle_pending_signal(CPUArchState *cpu_env, int sig,
> + struct emulated_sigtable *k)
> +{
> + CPUState *cpu = env_cpu(cpu_env);
> + TaskState *ts = cpu->opaque;
> + struct qemu_sigqueue *q;
> + struct target_sigaction *sa;
> + int code;
> + sigset_t set;
> + abi_ulong handler;
> + target_siginfo_t tinfo;
> + target_sigset_t target_old_set;
> +
> + trace_user_handle_signal(cpu_env, sig);
> +
> + /* Dequeue signal. */
> + q = k->first;
> + k->first = q->next;
> + if (!k->first) {
> + k->pending = 0;
> + }
(The dequeue simplifies if you follow linux-user's way of handling
"queueing" a signal.)
> +
> + sig = gdb_handlesig(cpu, sig);
> + if (!sig) {
> + sa = NULL;
> + handler = TARGET_SIG_IGN;
> + } else {
> + sa = &sigact_table[sig - 1];
> + handler = sa->_sa_handler;
> + }
> +
> + if (do_strace) {
> + print_taken_signal(sig, &q->info);
> + }
> +
> + if (handler == TARGET_SIG_DFL) {
> + /*
> + * default handler : ignore some signal. The other are job
> + * control or fatal.
> + */
> + if (TARGET_SIGTSTP == sig || TARGET_SIGTTIN == sig ||
> + TARGET_SIGTTOU == sig) {
> + kill(getpid(), SIGSTOP);
> + } else if (TARGET_SIGCHLD != sig && TARGET_SIGURG != sig &&
> + TARGET_SIGINFO != sig &&
> + TARGET_SIGWINCH != sig && TARGET_SIGCONT != sig) {
> + force_sig(sig);
> + }
> + } else if (TARGET_SIG_IGN == handler) {
Avoid the yoda-conditionals, please.
> + /* ignore sig */
> + } else if (TARGET_SIG_ERR == handler) {
> + force_sig(sig);
Note that if you follow linux-user and my suggestion on
patch 21, these force_sig() calls become calls to
dump_core_and_abort(), unlike the one in setup_frame(),
which should be a "queue this signal". (The difference is
that here we know the process is definitely going to die,
because it has no valid handler for a fatal signal. In
setup_frame() the process might be able to continue, if it
has a signal handler for the SIGILL or SIGSEGV or whatever.)
> + } else {
> + /* compute the blocked signals during the handler execution */
> + sigset_t *blocked_set;
> +
> + target_to_host_sigset(&set, &sa->sa_mask);
> + /*
> + * SA_NODEFER indicates that the current signal should not be
> + * blocked during the handler.
> + */
> + if (!(sa->sa_flags & TARGET_SA_NODEFER)) {
> + sigaddset(&set, target_to_host_signal(sig));
> + }
> +
> + /*
> + * Save the previous blocked signal state to restore it at the
> + * end of the signal execution (see do_sigreturn).
> + */
> + host_to_target_sigset_internal(&target_old_set, &ts->signal_mask);
> +
> + blocked_set = ts->in_sigsuspend ?
> + &ts->sigsuspend_mask : &ts->signal_mask;
> + qemu_sigorset(&ts->signal_mask, blocked_set, &set);
> + ts->in_sigsuspend = false;
> + sigprocmask(SIG_SETMASK, &ts->signal_mask, NULL);
> +
> + /* XXX VM86 on x86 ??? */
> +
> + code = q->info.si_code;
> + /* prepare the stack frame of the virtual CPU */
> + if (sa->sa_flags & TARGET_SA_SIGINFO) {
> + tswap_siginfo(&tinfo, &q->info);
Oh, you're doing the tswap_siginfo() here. If you really want to
do that, then the setup_frame() should be able to do a simple
structure-copy I think and doesn't need the logic to figure out
which union fields are relevant. But putting the tswap_siginfo()
inside setup_frame() would match where linux-user does it.
> + setup_frame(sig, code, sa, &target_old_set, &tinfo, cpu_env);
> + } else {
> + setup_frame(sig, code, sa, &target_old_set, NULL, cpu_env);
> + }
> + if (sa->sa_flags & TARGET_SA_RESETHAND) {
> + sa->_sa_handler = TARGET_SIG_DFL;
> + }
> + }
> + if (q != &k->info) {
> + free_sigqueue(cpu_env, q);
> + }
> +}
> +
> void process_pending_signals(CPUArchState *cpu_env)
> {
> }
> --
> 2.33.1
thanks
-- PMM
