[PATCH v2 34/40] bsd-user/signal.c: process_pending_signals

From: Warner Losh <imp@bsdimp.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Stacey Son <sson@FreeBSD.org>, Kyle Evans <kevans@freebsd.org>,
	Richard Henderson <richard.henderson@linaro.org>,
	def@FreeBSD.org, jrtc27@FreeBSD.org, Warner Losh <imp@bsdimp.com>
Subject: [PATCH v2 34/40] bsd-user/signal.c: process_pending_signals
Date: Mon, 24 Jan 2022 18:29:41 -0700	[thread overview]
Message-ID: <20220125012947.14974-35-imp@bsdimp.com> (raw)
In-Reply-To: <20220125012947.14974-1-imp@bsdimp.com>

Process the currently queued signals.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Kyle Evans <kevans@freebsd.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/signal.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/bsd-user/signal.c b/bsd-user/signal.c
index aef1fa95490..9ec4354d232 100644
--- a/bsd-user/signal.c
+++ b/bsd-user/signal.c
@@ -755,8 +755,62 @@ static void handle_pending_signal(CPUArchState *env, int sig,
     }
 }
 
-void process_pending_signals(CPUArchState *cpu_env)
+void process_pending_signals(CPUArchState *env)
 {
+    CPUState *cpu = env_cpu(env);
+    int sig;
+    sigset_t *blocked_set, set;
+    struct emulated_sigtable *k;
+    TaskState *ts = cpu->opaque;
+
+    while (qatomic_read(&ts->signal_pending)) {
+        sigfillset(&set);
+        sigprocmask(SIG_SETMASK, &set, 0);
+
+    restart_scan:
+        sig = ts->sync_signal.pending;
+        if (sig) {
+            /*
+             * Synchronous signals are forced by the emulated CPU in some way.
+             * If they are set to ignore, restore the default handler (see
+             * sys/kern_sig.c trapsignal() and execsigs() for this behavior)
+             * though maybe this is done only when forcing exit for non SIGCHLD.
+             */
+            if (sigismember(&ts->signal_mask, target_to_host_signal(sig)) ||
+                sigact_table[sig - 1]._sa_handler == TARGET_SIG_IGN) {
+                sigdelset(&ts->signal_mask, target_to_host_signal(sig));
+                sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
+            }
+            handle_pending_signal(env, sig, &ts->sync_signal);
+        }
+
+        k = ts->sigtab;
+        for (sig = 1; sig <= TARGET_NSIG; sig++, k++) {
+            blocked_set = ts->in_sigsuspend ?
+                &ts->sigsuspend_mask : &ts->signal_mask;
+            if (k->pending &&
+                !sigismember(blocked_set, target_to_host_signal(sig))) {
+                handle_pending_signal(env, sig, k);
+                /*
+                 * Restart scan from the beginning, as handle_pending_signal
+                 * might have resulted in a new synchronous signal (eg SIGSEGV).
+                 */
+                goto restart_scan;
+            }
+        }
+
+        /*
+         * unblock signals and check one more time. Unblocking signals may cause
+         * us to take anothe rhost signal, which will set signal_pending again.
+         */
+        qatomic_set(&ts->signal_pending, 0);
+        ts->in_sigsuspend = false;
+        set = ts->signal_mask;
+        sigdelset(&set, SIGSEGV);
+        sigdelset(&set, SIGBUS);
+        sigprocmask(SIG_SETMASK, &set, 0);
+    }
+    ts->in_sigsuspend = false;
 }
 
 void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
-- 
2.33.1


