Wake up libuv main loop on SIGINT

Author: yuyichao

src/init.c

@@ -544,6 +544,7 @@ void _julia_init(JL_IMAGE_SEARCH rel)
     ios_set_io_wait_func = jl_set_io_wait;
     jl_io_loop = uv_default_loop(); // this loop will internal events (spawning process etc.),
                                     // best to call this first, since it also initializes libuv
+    jl_init_signal_async();
     restore_signals();
     jl_resolve_sysimg_location(rel);
     // loads sysimg if available, and conditionally sets jl_options.cpu_target

src/jl_uv.c

@@ -47,6 +47,26 @@
 extern "C" {
 #endif
 
+static uv_async_t signal_async;
+
+static void jl_signal_async_cb(uv_async_t *hdl)
+{
+    // This should abort the current loop and the julia code it returns to
+    // or the safepoint in the callers of `uv_run` should throw the exception.
+    (void)hdl;
+    uv_stop(jl_io_loop);
+}
+
+void jl_wake_libuv(void)
+{
+    uv_async_send(&signal_async);
+}
+
+void jl_init_signal_async(void)
+{
+    uv_async_init(jl_io_loop, &signal_async, jl_signal_async_cb);
+}
+
 extern jl_module_t *jl_old_base_module;
 static jl_value_t *close_cb = NULL;
 
@@ -80,6 +100,8 @@ JL_DLLEXPORT void jl_uv_closeHandle(uv_handle_t *handle)
     // also let the client app do its own cleanup
     if (handle->type != UV_FILE && handle->data)
         jl_uv_call_close_callback((jl_value_t*)handle->data);
+    if (handle == (uv_handle_t*)&signal_async)
+        return;
     free(handle);
 }
 
@@ -114,6 +136,7 @@ JL_DLLEXPORT int jl_run_once(uv_loop_t *loop)
 {
     if (loop) {
         loop->stop_flag = 0;
+        jl_gc_safepoint();
         return uv_run(loop,UV_RUN_ONCE);
     }
     else return 0;
@@ -123,6 +146,7 @@ JL_DLLEXPORT void jl_run_event_loop(uv_loop_t *loop)
 {
     if (loop) {
         loop->stop_flag = 0;
+        jl_gc_safepoint();
         uv_run(loop,UV_RUN_DEFAULT);
     }
 }
@@ -131,6 +155,7 @@ JL_DLLEXPORT int jl_process_events(uv_loop_t *loop)
 {
     if (loop) {
         loop->stop_flag = 0;
+        jl_gc_safepoint();
         return uv_run(loop,UV_RUN_NOWAIT);
     }
     else return 0;

src/julia_internal.h

@@ -255,6 +255,7 @@ void jl_init_root_task(void *stack, size_t ssize);
 void jl_init_serializer(void);
 void jl_gc_init(void);
 void jl_init_restored_modules(jl_array_t *init_order);
+void jl_init_signal_async(void);
 
 void _julia_init(JL_IMAGE_SEARCH rel);
 #ifdef COPY_STACKS
@@ -309,6 +310,7 @@ void jl_safepoint_defer_sigint(void);
 // Return `1` if the sigint should be delivered and `0` if there's no sigint
 // to be delivered.
 int jl_safepoint_consume_sigint(void);
+void jl_wake_libuv(void);
 
 #ifdef JULIA_ENABLE_THREADING
 jl_get_ptls_states_func jl_get_ptls_states_getter(void);

src/signals-mach.c

@@ -293,6 +293,9 @@ static void jl_try_deliver_sigint(void)
         jl_clear_force_sigint();
         jl_throw_in_thread(0, thread, jl_interrupt_exception);
     }
+    else {
+        jl_wake_libuv();
+    }
 
     ret = thread_resume(thread);
     HANDLE_MACH_ERROR("thread_resume", ret);

src/signals-unix.c

@@ -172,6 +172,7 @@ static void jl_try_deliver_sigint(void)
 {
     jl_tls_states_t *ptls = jl_all_task_states[0].ptls;
     jl_safepoint_enable_sigint();
+    jl_wake_libuv();
     jl_atomic_store_release(&ptls->signal_request, 2);
     // This also makes sure `sleep` is aborted.
     pthread_kill(jl_all_task_states[0].system_id, SIGUSR2);

src/signals-win.c

@@ -45,6 +45,7 @@ static void jl_try_throw_sigint(void)
 {
     jl_tls_states_t *ptls = jl_get_ptls_states();
     jl_safepoint_enable_sigint();
+    jl_wake_libuv();
     int force = jl_check_force_sigint();
     if (force || (!ptls->defer_signal && ptls->io_wait)) {
         jl_safepoint_consume_sigint();
@@ -127,6 +128,7 @@ static void jl_try_deliver_sigint(void)
 {
     jl_tls_states_t *ptls = jl_all_task_states[0].ptls;
     jl_safepoint_enable_sigint();
+    jl_wake_libuv();
     if ((DWORD)-1 == SuspendThread(hMainThread)) {
         // error
         jl_safe_printf("error: SuspendThread failed\n");