Handle exit() from pthread by posting exitProcess back to main thread

Author: sbc100

src/library_pthread.js

@@ -351,17 +351,18 @@ var LibraryPThread = {
           if (detached) {
             PThread.returnWorkerToPool(worker);
           }
-#if EXIT_RUNTIME // If building with -s EXIT_RUNTIME=0, no thread will post this message, so don't even compile it in.
         } else if (cmd === 'exitProcess') {
           // A pthread has requested to exit the whole application process (runtime).
+#if ASSERTIONS
+          err("exitProcess requested by worker");
+#endif
           noExitRuntime = false;
           try {
             exit(d['returnCode']);
           } catch (e) {
             if (e instanceof ExitStatus) return;
             throw e;
           }
-#endif
         } else if (cmd === 'cancelDone') {
           PThread.returnWorkerToPool(worker);
         } else if (cmd === 'objectTransfer') {

src/postamble.js

@@ -363,6 +363,16 @@ function checkUnflushedContent() {
 
 /** @param {boolean|number=} implicit */
 function exit(status, implicit) {
+#if USE_PTHREADS
+  if (ENVIRONMENT_IS_PTHREAD) {
+    // When running in a pthread we propagate the exit out the worker.js where
+    // it gets tranlated in an 'exitProcess' message on the main thread.
+    // This allows the main thread to decide if (or if not) it wants to bring
+    // down the entire application, based on the main thread's noExitRuntime.
+    throw new ExitStatus(status);
+  }
+#endif
+
 #if ASSERTIONS
 #if EXIT_RUNTIME == 0
   checkUnflushedContent();

src/worker.js

@@ -193,8 +193,12 @@ this.onmessage = function(e) {
 #if STACK_OVERFLOW_CHECK
         Module['checkStackCookie']();
 #endif
-#if !MINIMAL_RUNTIME // In MINIMAL_RUNTIME the noExitRuntime concept does not apply to pthreads. To exit a pthread with live runtime, use the function emscripten_unwind_to_js_event_loop() in the pthread body.
-        // The thread might have finished without calling pthread_exit(). If so, then perform the exit operation ourselves.
+#if !MINIMAL_RUNTIME
+        // In MINIMAL_RUNTIME the noExitRuntime concept does not apply to
+        // pthreads. To exit a pthread with live runtime, use the function
+        // emscripten_unwind_to_js_event_loop() in the pthread body.
+        // The thread might have finished without calling pthread_exit(). If so,
+        // then perform the exit operation ourselves.
         // (This is a no-op if explicit pthread_exit() had been called prior.)
         if (!Module['getNoExitRuntime']())
 #endif
@@ -213,14 +217,28 @@ this.onmessage = function(e) {
             throw ex;
           }
 #endif
-#if MINIMAL_RUNTIME
           // ExitStatus not present in MINIMAL_RUNTIME
-          Module['PThread'].threadExit(-2);
-          throw ex; // ExitStatus not present in MINIMAL_RUNTIME
-#else
-          Module['PThread'].threadExit((ex instanceof Module['ExitStatus']) ? ex.status : -2);
-          if (!(ex instanceof Module['ExitStatus'])) throw ex;
+#if !MINIMAL_RUNTIME
+          if (ex instanceof Module['ExitStatus']) {
+            if (Module['getNoExitRuntime']()) {
+#if ASSERTIONS
+              err('Pthread 0x' + _pthread_self().toString(16) + ' called exit(), ignoring due to noExitRuntime.');
 #endif
+            } else {
+#if ASSERTIONS
+              err('Pthread 0x' + _pthread_self().toString(16) + ' called exit(), quitting process.');
+#endif
+              // Send the exitProcess message back to main thread.
+              // its then up to the main
+              postMessage({ 'cmd': 'exitProcess', 'returnCode': ex.status });
+            }
+          }
+          else
+#endif
+          {
+            Module['PThread'].threadExit(-2);
+            throw ex;
+          }
 #if ASSERTIONS
         } else {
           // else e == 'unwind', and we should fall through here and keep the pthread alive for asynchronous events.

tests/core/pthread/test_pthread_exit_runtime.c

@@ -0,0 +1,18 @@
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+pthread_t t;
+
+void* thread_main_exit(void* arg) {
+  printf("calling exit\n");
+  exit(42);
+}
+
+int main() {
+  printf("main\n");
+  pthread_create(&t, NULL, thread_main_exit, NULL);
+  pthread_join(t, NULL);
+  printf("done join\n");
+  return 0;
+}

tests/core/pthread/test_pthread_exit_runtime.out

@@ -0,0 +1 @@
+onExit status: 42

tests/test_core.py

@@ -8090,6 +8090,16 @@ def test_pthread_exceptions(self):
     self.emcc_args += ['-fexceptions']
     self.do_run_in_out_file_test('tests', 'core', 'pthread', 'exceptions.cpp')
 
+  @node_pthreads
+  def test_pthread_exit_runtime(self):
+    self.add_pre_run("Module['onExit'] = function(status) { out('onExit status: ' + status); };")
+    self.set_setting('PROXY_TO_PTHREAD')
+    self.set_setting('PTHREAD_POOL_SIZE', '2')
+    self.do_run_in_out_file_test('tests', 'core', 'pthread', 'test_pthread_exit_runtime.c', assert_returncode=42)
+
+    self.set_setting('EXIT_RUNTIME')
+    self.do_run_in_out_file_test('tests', 'core', 'pthread', 'test_pthread_exit_runtime.c', assert_returncode=42)
+
   def test_emscripten_atomics_stub(self):
     self.do_run_in_out_file_test('tests', 'core', 'pthread', 'emscripten_atomics.c')