softmmu: add means to pass an exit code when requesting a shutdown

As of now, the exit code was either EXIT_FAILURE when a panic shutdown
was requested or EXIT_SUCCESS otherwise.
However, some hardware could want to pass more complex exit codes. Thus,
introduce a new shutdown request function allowing that.

Signed-off-by: Clément Chigot <chigot@adacore.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231003071427.188697-2-chigot@adacore.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

include/sysemu/runstate.h

@@ -68,6 +68,8 @@ void qemu_system_wakeup_request(WakeupReason reason, Error **errp);
 void qemu_system_wakeup_enable(WakeupReason reason, bool enabled);
 void qemu_register_wakeup_notifier(Notifier *notifier);
 void qemu_register_wakeup_support(void);
+void qemu_system_shutdown_request_with_code(ShutdownCause reason,
+                                            int exit_code);
 void qemu_system_shutdown_request(ShutdownCause reason);
 void qemu_system_powerdown_request(void);
 void qemu_register_powerdown_notifier(Notifier *notifier);

system/runstate.c

@@ -385,6 +385,7 @@ void vm_state_notify(bool running, RunState state)
 
 static ShutdownCause reset_requested;
 static ShutdownCause shutdown_requested;
+static int shutdown_exit_code = EXIT_SUCCESS;
 static int shutdown_signal;
 static pid_t shutdown_pid;
 static int powerdown_requested;
@@ -664,6 +665,13 @@ void qemu_system_killed(int signal, pid_t pid)
     qemu_notify_event();
 }
 
+void qemu_system_shutdown_request_with_code(ShutdownCause reason,
+                                            int exit_code)
+{
+    shutdown_exit_code = exit_code;
+    qemu_system_shutdown_request(reason);
+}
+
 void qemu_system_shutdown_request(ShutdownCause reason)
 {
     trace_qemu_system_shutdown_request(reason);
@@ -725,7 +733,9 @@ static bool main_loop_should_exit(int *status)
         if (shutdown_action == SHUTDOWN_ACTION_PAUSE) {
             vm_stop(RUN_STATE_SHUTDOWN);
         } else {
-            if (request == SHUTDOWN_CAUSE_GUEST_PANIC &&
+            if (shutdown_exit_code != EXIT_SUCCESS) {
+                *status = shutdown_exit_code;
+            } else if (request == SHUTDOWN_CAUSE_GUEST_PANIC &&
                 panic_action == PANIC_ACTION_EXIT_FAILURE) {
                 *status = EXIT_FAILURE;
             }