1 files changed, 44 insertions, 6 deletions

diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index 76c5351a90..26c81e9aca 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -44,6 +44,7 @@
 
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/connected_channel.h"
+#include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/stack_lockfree.h"
@@ -211,6 +212,11 @@ struct grpc_server {
   gpr_mu mu_global; /* mutex for server and channel state */
   gpr_mu mu_call;   /* mutex for call-specific state */
 
+  /* startup synchronization: flag is protected by mu_global, signals whether
+     we are doing the listener start routine or not */
+  bool starting;
+  gpr_cv starting_cv;
+
   registered_method *registered_methods;
   /** one request matcher for unregistered methods */
   request_matcher unregistered_request_matcher;
@@ -388,6 +394,7 @@ static void server_delete(grpc_exec_ctx *exec_ctx, grpc_server *server) {
   grpc_channel_args_destroy(exec_ctx, server->channel_args);
   gpr_mu_destroy(&server->mu_global);
   gpr_mu_destroy(&server->mu_call);
+  gpr_cv_destroy(&server->starting_cv);
   while ((rm = server->registered_methods) != NULL) {
     server->registered_methods = rm->next;
     if (server->started) {
@@ -1000,6 +1007,15 @@ void grpc_server_register_completion_queue(grpc_server *server,
   GRPC_API_TRACE(
       "grpc_server_register_completion_queue(server=%p, cq=%p, reserved=%p)", 3,
       (server, cq, reserved));
+
+  if (grpc_get_cq_completion_type(cq) != GRPC_CQ_NEXT) {
+    gpr_log(GPR_INFO,
+            "Completion queue which is not of type GRPC_CQ_NEXT is being "
+            "registered as a server-completion-queue");
+    /* Ideally we should log an error and abort but ruby-wrapped-language API
+       calls grpc_completion_queue_pluck() on server completion queues */
+  }
+
   register_completion_queue(server, cq, false, reserved);
 }
 
@@ -1021,6 +1037,7 @@ grpc_server *grpc_server_create(const grpc_channel_args *args, void *reserved) {
 
   gpr_mu_init(&server->mu_global);
   gpr_mu_init(&server->mu_call);
+  gpr_cv_init(&server->starting_cv);
 
   /* decremented by grpc_server_destroy */
   gpr_ref_init(&server->internal_refcount, 1);
@@ -1077,8 +1094,22 @@ void *grpc_server_register_method(
   return m;
 }
 
+static void start_listeners(grpc_exec_ctx *exec_ctx, void *s,
+                            grpc_error *error) {
+  grpc_server *server = s;
+  for (listener *l = server->listeners; l; l = l->next) {
+    l->start(exec_ctx, server, l->arg, server->pollsets, server->pollset_count);
+  }
+
+  gpr_mu_lock(&server->mu_global);
+  server->starting = false;
+  gpr_cv_signal(&server->starting_cv);
+  gpr_mu_unlock(&server->mu_global);
+
+  server_unref(exec_ctx, server);
+}
+
 void grpc_server_start(grpc_server *server) {
-  listener *l;
   size_t i;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
@@ -1112,10 +1143,11 @@ void grpc_server_start(grpc_server *server) {
                          (size_t)server->max_requested_calls_per_cq, server);
   }
 
-  for (l = server->listeners; l; l = l->next) {
-    l->start(&exec_ctx, server, l->arg, server->pollsets,
-             server->pollset_count);
-  }
+  server_ref(server);
+  server->starting = true;
+  grpc_closure_sched(&exec_ctx, grpc_closure_create(start_listeners, server,
+                                                    grpc_executor_scheduler),
+                     GRPC_ERROR_NONE);
 
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -1249,8 +1281,14 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
   GRPC_API_TRACE("grpc_server_shutdown_and_notify(server=%p, cq=%p, tag=%p)", 3,
                  (server, cq, tag));
 
-  /* lock, and gather up some stuff to do */
+  /* wait for startup to be finished: locks mu_global */
   gpr_mu_lock(&server->mu_global);
+  while (server->starting) {
+    gpr_cv_wait(&server->starting_cv, &server->mu_global,
+                gpr_inf_future(GPR_CLOCK_REALTIME));
+  }
+
+  /* stay locked, and gather up some stuff to do */
   grpc_cq_begin_op(cq, tag);
   if (server->shutdown_published) {
     grpc_cq_end_op(&exec_ctx, cq, tag, GRPC_ERROR_NONE, done_published_shutdown,