Add a load_status callback hook that is invoked at the end of chrome LoadApp.

src/trusted/service_runtime/sel_main_chrome.c

Index: src/trusted/service_runtime/sel_main_chrome.c
diff --git a/src/trusted/service_runtime/sel_main_chrome.c b/src/trusted/service_runtime/sel_main_chrome.c
index c4a013e802cdde0a7cab5e50c098101ee0fa0ff3..4129ff63bda588514f800ea40189d971538a5da4 100644
--- a/src/trusted/service_runtime/sel_main_chrome.c
+++ b/src/trusted/service_runtime/sel_main_chrome.c
@@ -44,6 +44,7 @@
 static int g_initialized = 0;
 
 static void (*g_fatal_error_handler)(const char *data, size_t bytes) = NULL;
+static void (*g_load_status_callback)(int load_status) = NULL;
 
 static const int default_argc = 1;
 static const char *const default_argv[1] = {"NaClMain"};
@@ -76,6 +77,13 @@ void NaClSetFatalErrorCallback(void (*func)(const char *data, size_t bytes)) {
   NaClErrorLogHookInit(NaClFatalErrorHandlerCallback, NULL);
 }
 
+void NaClSetLoadStatusCallback(void (*func)(int load_status)) {
+  CHECK(g_initialized);
+  if (g_load_status_callback != NULL)
+    NaClLog(LOG_FATAL, "NaClSetLoadStatusCallback called twice.\n");
+  g_load_status_callback = func;
+}
+
 struct NaClChromeMainArgs *NaClChromeMainArgsCreate(void) {
   struct NaClChromeMainArgs *args;
 
@@ -371,17 +379,35 @@ static int LoadApp(struct NaClApp *nap, struct NaClChromeMainArgs *args) {
 #endif
   }
 
+  if (g_load_status_callback != NULL) {
+    g_load_status_callback(LOAD_OK);
+  }
   return LOAD_OK;
 
 done:
   fflush(stdout);
 
   /*
-   * If there is a secure command channel, we sent an RPC reply with
-   * the reason that the nexe was rejected.  If we exit now, that
-   * reply may still be in-flight and the various channel closure (esp
-   * reverse channel) may be detected first.  This would result in a
-   * crash being reported, rather than the error in the RPC reply.
+   * If there is a load_status_callback, call that now. TODO(jvoung): remove
+   * NaClBlockIfCommandChannelExists() and just call g_load_status_callback
+   * to indicate the load_status.
+   */
+  if (g_load_status_callback != NULL) {
+    /* Don't return LOAD_OK if we had some failure loading. */
+    if (LOAD_OK == errcode) {
+      errcode = LOAD_INTERNAL;
+    }
+    g_load_status_callback(errcode);
+    NaClLog(LOG_ERROR, "reap logs\n");
+    NaClLogRunAbortBehavior();
+    return errcode;
+  }
+  /*
+   * If there is no load_status_callback, but there is a secure command channel,
+   * we sent an RPC reply with the reason that the nexe was rejected.
+   * If we exit now, that reply may still be in-flight and the various
+   * channel closure (esp reverse channel) may be detected first.  This would
+   * result in a crash being reported, rather than the error in the RPC reply.
    * Instead, we wait for the hard-shutdown on the command channel.
    */
   if (LOAD_OK != errcode) {