diff --git a/pinos/client/connection.c b/pinos/client/connection.c
index fa7299bf1..e39c6f313 100644
--- a/pinos/client/connection.c
+++ b/pinos/client/connection.c
@@ -98,6 +98,17 @@ connection_parse_client_update (PinosConnection *conn, PinosMessageClientUpdate
     m->props = pinos_serialize_dict_deserialize (p, SPA_PTR_TO_INT (m->props));
 }
 
+static void
+connection_parse_error (PinosConnection *conn, PinosMessageError *m)
+{
+  void *p;
+
+  p = conn->in.data;
+  memcpy (m, p, sizeof (PinosMessageError));
+  if (m->error)
+    m->error = SPA_MEMBER (p, SPA_PTR_TO_INT (m->error), const char);
+}
+
 static void
 connection_parse_notify_global (PinosConnection *conn, PinosMessageNotifyGlobal *ng)
 {
@@ -198,6 +209,8 @@ connection_parse_node_info (PinosConnection *conn, PinosMessageNodeInfo *m)
 
     if (m->info->name)
       m->info->name = SPA_MEMBER (di, SPA_PTR_TO_INT (m->info->name), const char);
+    if (m->info->error)
+      m->info->error = SPA_MEMBER (di, SPA_PTR_TO_INT (m->info->error), const char);
     if (m->info->props)
       m->info->props = pinos_serialize_dict_deserialize (di, SPA_PTR_TO_INT (m->info->props));
   }
@@ -374,6 +387,29 @@ connection_add_client_update (PinosConnection *conn,
   }
 }
 
+static void
+connection_add_error (PinosConnection *conn,
+                      uint32_t         dest_id,
+                      PinosMessageError *m)
+{
+  size_t len;
+  void *p;
+  PinosMessageError *d;
+
+  /* calc len */
+  len = sizeof (PinosMessageError);
+  len += m->error ? strlen (m->error) + 1 : 0;
+
+  p = connection_add_message (conn, dest_id, PINOS_MESSAGE_ERROR, len);
+  memcpy (p, m, sizeof (PinosMessageError));
+  d = p;
+
+  if (m->error) {
+    strcpy (p, m->error);
+    d->error = SPA_INT_TO_PTR (SPA_PTRDIFF (p, d));
+  }
+}
+
 static void
 connection_add_notify_global (PinosConnection *conn,
                               uint32_t         dest_id,
@@ -593,6 +629,7 @@ connection_add_node_info (PinosConnection *conn, uint32_t dest_id, PinosMessageN
   if (m->info) {
     len += sizeof (PinosNodeInfo);
     len += m->info->name ? strlen (m->info->name) + 1 : 0;
+    len += m->info->error ? strlen (m->info->error) + 1 : 0;
     len += pinos_serialize_dict_get_size (m->info->props);
   }
 
@@ -615,6 +652,12 @@ connection_add_node_info (PinosConnection *conn, uint32_t dest_id, PinosMessageN
       di->name = SPA_INT_TO_PTR (SPA_PTRDIFF (p, di));
       p += slen;
     }
+    if (m->info->error) {
+      slen = strlen (m->info->error) + 1;
+      memcpy (p, m->info->error, slen);
+      di->error = SPA_INT_TO_PTR (SPA_PTRDIFF (p, di));
+      p += slen;
+    }
     if (m->info->props) {
       len = pinos_serialize_dict_serialize (p, m->info->props);
       di->props = SPA_INT_TO_PTR (SPA_PTRDIFF (p, di));
@@ -952,7 +995,11 @@ pinos_connection_new (int fd)
   PinosConnection *c;
 
   c = calloc (1, sizeof (PinosConnection));
+  if (c == NULL)
+    return NULL;
+
   pinos_log_debug ("connection %p: new", c);
+
   c->fd = fd;
   c->out.buffer_data = malloc (MAX_BUFFER_SIZE);
   c->out.buffer_maxsize = MAX_BUFFER_SIZE;
@@ -960,7 +1007,16 @@ pinos_connection_new (int fd)
   c->in.buffer_maxsize = MAX_BUFFER_SIZE;
   c->in.update = true;
 
+  if (c->out.buffer_data == NULL || c->in.buffer_data == NULL)
+    goto no_mem;
+
   return c;
+
+no_mem:
+  free (c->out.buffer_data);
+  free (c->in.buffer_data);
+  free (c);
+  return NULL;
 }
 
 void
@@ -1069,6 +1125,10 @@ pinos_connection_parse_message (PinosConnection *conn,
       memcpy (message, conn->in.data, sizeof (PinosMessageNotifyDone));
       break;
 
+    case PINOS_MESSAGE_ERROR:
+      connection_parse_error (conn, message);
+      break;
+
     case PINOS_MESSAGE_GET_REGISTRY:
       if (conn->in.size < sizeof (PinosMessageGetRegistry))
         return false;
@@ -1265,6 +1325,10 @@ pinos_connection_add_message (PinosConnection  *conn,
       memcpy (p, message, sizeof (PinosMessageNotifyDone));
       break;
 
+    case PINOS_MESSAGE_ERROR:
+      connection_add_error (conn, dest_id, message);
+      break;
+
     case PINOS_MESSAGE_GET_REGISTRY:
       p = connection_add_message (conn, dest_id, type, sizeof (PinosMessageGetRegistry));
       memcpy (p, message, sizeof (PinosMessageGetRegistry));
diff --git a/pinos/client/connection.h b/pinos/client/connection.h
index 4f8abb0e1..ed28606d7 100644
--- a/pinos/client/connection.h
+++ b/pinos/client/connection.h
@@ -39,6 +39,7 @@ typedef enum {
 
   PINOS_MESSAGE_SYNC,
   PINOS_MESSAGE_NOTIFY_DONE,
+  PINOS_MESSAGE_ERROR,
   PINOS_MESSAGE_GET_REGISTRY,
   PINOS_MESSAGE_REMOVE_ID,
   PINOS_MESSAGE_CORE_INFO,
@@ -103,6 +104,13 @@ typedef struct {
   uint32_t     seq;
 } PinosMessageNotifyDone;
 
+/* PINOS_MESSAGE_ERROR */
+typedef struct {
+  uint32_t     id;
+  SpaResult    res;
+  const char  *error;
+} PinosMessageError;
+
 /* PINOS_MESSAGE_GET_REGISTRY */
 typedef struct {
   uint32_t     seq;
@@ -148,7 +156,7 @@ typedef struct {
 /* PINOS_MESSAGE_NOTIFY_GLOBAL */
 typedef struct {
   uint32_t     id;
-  const char * type;
+  const char  *type;
 } PinosMessageNotifyGlobal;
 
 /* PINOS_MESSAGE_NOTIFY_GLOBAL_REMOVE */
diff --git a/pinos/client/context.c b/pinos/client/context.c
index 41bbc0778..dd467b4a5 100644
--- a/pinos/client/context.c
+++ b/pinos/client/context.c
@@ -37,9 +37,6 @@ typedef struct {
   SpaSource source;
 
   bool disconnecting;
-
-  PinosSubscriptionFunc  subscribe_func;
-  void                  *subscribe_data;
 } PinosContextImpl;
 
 /**
@@ -112,6 +109,7 @@ core_dispatch_func (void             *object,
       PinosSubscriptionEvent event;
 
       pinos_log_debug ("got core info %d", type);
+
       if (proxy->user_data == NULL)
         event = PINOS_SUBSCRIPTION_EVENT_NEW;
       else
@@ -119,13 +117,11 @@ core_dispatch_func (void             *object,
 
       proxy->user_data = pinos_core_info_update (proxy->user_data, m->info);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              event,
-                              proxy->type,
-                              proxy->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         event,
+                         proxy->type,
+                         proxy->id);
       break;
     }
     case PINOS_MESSAGE_NOTIFY_DONE:
@@ -136,6 +132,12 @@ core_dispatch_func (void             *object,
         context_set_state (this, PINOS_CONTEXT_STATE_CONNECTED, NULL);
       break;
     }
+    case PINOS_MESSAGE_ERROR:
+    {
+      PinosMessageError *m = message;
+      context_set_state (this, PINOS_CONTEXT_STATE_ERROR, m->error);
+      break;
+    }
     case PINOS_MESSAGE_REMOVE_ID:
     {
       PinosMessageRemoveId *m = message;
@@ -180,13 +182,11 @@ module_dispatch_func (void             *object,
 
       proxy->user_data = pinos_module_info_update (proxy->user_data, m->info);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              event,
-                              proxy->type,
-                              proxy->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         event,
+                         proxy->type,
+                         proxy->id);
       break;
     }
 
@@ -221,13 +221,11 @@ node_dispatch_func (void             *object,
 
       proxy->user_data = pinos_node_info_update (proxy->user_data, m->info);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              event,
-                              proxy->type,
-                              proxy->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         event,
+                         proxy->type,
+                         proxy->id);
       break;
     }
     default:
@@ -261,13 +259,11 @@ client_dispatch_func (void             *object,
 
       proxy->user_data = pinos_client_info_update (proxy->user_data, m->info);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              event,
-                              proxy->type,
-                              proxy->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         event,
+                         proxy->type,
+                         proxy->id);
       break;
     }
     default:
@@ -301,13 +297,11 @@ link_dispatch_func (void             *object,
 
       proxy->user_data = pinos_link_info_update (proxy->user_data, m->info);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              event,
-                              proxy->type,
-                              proxy->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         event,
+                         proxy->type,
+                         proxy->id);
       break;
     }
     default:
@@ -338,24 +332,32 @@ registry_dispatch_func (void             *object,
         proxy = pinos_proxy_new (this,
                                  SPA_ID_INVALID,
                                  this->uri.node);
+        if (proxy == NULL)
+          goto no_mem;
         proxy->dispatch_func = node_dispatch_func;
         proxy->dispatch_data = impl;
       } else if (!strcmp (ng->type, PINOS_MODULE_URI)) {
         proxy = pinos_proxy_new (this,
                                  SPA_ID_INVALID,
                                  this->uri.module);
+        if (proxy == NULL)
+          goto no_mem;
         proxy->dispatch_func = module_dispatch_func;
         proxy->dispatch_data = impl;
       } else if (!strcmp (ng->type, PINOS_CLIENT_URI)) {
         proxy = pinos_proxy_new (this,
                                  SPA_ID_INVALID,
                                  this->uri.client);
+        if (proxy == NULL)
+          goto no_mem;
         proxy->dispatch_func = client_dispatch_func;
         proxy->dispatch_data = impl;
       } else if (!strcmp (ng->type, PINOS_LINK_URI)) {
         proxy = pinos_proxy_new (this,
                                  SPA_ID_INVALID,
                                  this->uri.link);
+        if (proxy == NULL)
+          goto no_mem;
         proxy->dispatch_func = link_dispatch_func;
         proxy->dispatch_data = impl;
       }
@@ -376,13 +378,11 @@ registry_dispatch_func (void             *object,
       PinosMessageNotifyGlobalRemove *ng = message;
       pinos_log_debug ("got global remove %u", ng->id);
 
-      if (impl->subscribe_func) {
-        impl->subscribe_func (this,
-                              PINOS_SUBSCRIPTION_EVENT_REMOVE,
-                              SPA_ID_INVALID,
-                              ng->id,
-                              impl->subscribe_data);
-      }
+      pinos_signal_emit (&this->subscription,
+                         this,
+                         PINOS_SUBSCRIPTION_EVENT_REMOVE,
+                         SPA_ID_INVALID,
+                         ng->id);
       break;
     }
     default:
@@ -390,6 +390,9 @@ registry_dispatch_func (void             *object,
       break;
   }
   return SPA_RESULT_OK;
+
+no_mem:
+  return SPA_RESULT_NO_MEMORY;
 }
 
 static void
@@ -477,6 +480,9 @@ pinos_context_new (PinosLoop       *loop,
   PinosContext *this;
 
   impl = calloc (1, sizeof (PinosContextImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   pinos_log_debug ("context %p: new", impl);
 
@@ -484,6 +490,9 @@ pinos_context_new (PinosLoop       *loop,
 
   if (properties == NULL)
     properties = pinos_properties_new ("application.name", name, NULL);
+  if (properties == NULL)
+    goto no_mem;
+
   pinos_fill_context_properties (properties);
   this->properties = properties;
 
@@ -503,9 +512,15 @@ pinos_context_new (PinosLoop       *loop,
   spa_list_init (&this->proxy_list);
 
   pinos_signal_init (&this->state_changed);
+  pinos_signal_init (&this->subscription);
   pinos_signal_init (&this->destroy_signal);
 
   return this;
+
+no_mem:
+  free (this->name);
+  free (impl);
+  return NULL;
 }
 
 void
@@ -523,14 +538,10 @@ pinos_context_destroy (PinosContext *context)
   spa_list_for_each_safe (proxy, t2, &context->proxy_list, link)
     pinos_proxy_destroy (proxy);
 
-  if (context->name)
-    free (context->name);
+  free (context->name);
   if (context->properties)
     pinos_properties_free (context->properties);
-
-  if (context->error)
-    free (context->error);
-
+  free (context->error);
   free (impl);
 }
 
@@ -579,8 +590,7 @@ pinos_context_connect (PinosContext      *context)
   if (name_size > (int)sizeof addr.sun_path) {
     pinos_log_error ("socket path \"%s/%s\" plus null terminator exceeds 108 bytes",
                      runtime_dir, name);
-    close (fd);
-    return false;
+    goto error_close;
   };
 
   size = offsetof (struct sockaddr_un, sun_path) + name_size;
@@ -589,12 +599,14 @@ pinos_context_connect (PinosContext      *context)
     context_set_state (context,
                        PINOS_CONTEXT_STATE_ERROR,
                        "connect failed: %s", strerror (errno));
-    close (fd);
-    return false;
+    goto error_close;
   }
 
-  impl->fd = fd;
   impl->connection = pinos_connection_new (fd);
+  if (impl->connection == NULL)
+    goto error_close;
+
+  impl->fd = fd;
 
   pinos_loop_add_io (context->loop,
                      fd,
@@ -606,6 +618,9 @@ pinos_context_connect (PinosContext      *context)
   context->core_proxy = pinos_proxy_new (context,
                                          SPA_ID_INVALID,
                                          context->uri.core);
+  if (context->core_proxy == NULL)
+    goto no_proxy;
+
   context->core_proxy->dispatch_func = core_dispatch_func;
   context->core_proxy->dispatch_data = impl;
 
@@ -618,6 +633,9 @@ pinos_context_connect (PinosContext      *context)
   context->registry_proxy = pinos_proxy_new (context,
                                              SPA_ID_INVALID,
                                              context->uri.registry);
+  if (context->registry_proxy == NULL)
+    goto no_registry;
+
   context->registry_proxy->dispatch_func = registry_dispatch_func;
   context->registry_proxy->dispatch_data = impl;
 
@@ -628,6 +646,14 @@ pinos_context_connect (PinosContext      *context)
                             &grm,
                             true);
   return true;
+
+no_registry:
+  pinos_proxy_destroy (context->core_proxy);
+no_proxy:
+  pinos_connection_destroy (impl->connection);
+error_close:
+  close (fd);
+  return false;
 }
 
 /**
@@ -645,6 +671,8 @@ pinos_context_disconnect (PinosContext *context)
 
   impl->disconnecting = true;
 
+  pinos_proxy_destroy (context->registry_proxy);
+  pinos_proxy_destroy (context->core_proxy);
   pinos_connection_destroy (impl->connection);
   close (impl->fd);
 
@@ -653,17 +681,6 @@ pinos_context_disconnect (PinosContext *context)
   return true;
 }
 
-void
-pinos_context_subscribe (PinosContext           *context,
-                         PinosSubscriptionFunc   func,
-                         void                   *data)
-{
-  PinosContextImpl *impl = SPA_CONTAINER_OF (context, PinosContextImpl, this);
-
-  impl->subscribe_func = func;
-  impl->subscribe_data = data;
-}
-
 void
 pinos_context_get_core_info (PinosContext            *context,
                              PinosCoreInfoCallback    cb,
diff --git a/pinos/client/context.h b/pinos/client/context.h
index da4077114..4c67eb0e0 100644
--- a/pinos/client/context.h
+++ b/pinos/client/context.h
@@ -29,6 +29,7 @@ typedef struct _PinosContext PinosContext;
 #include <pinos/client/map.h>
 #include <pinos/client/loop.h>
 #include <pinos/client/properties.h>
+#include <pinos/client/subscribe.h>
 #include <pinos/client/proxy.h>
 #include <pinos/client/uri.h>
 
@@ -66,19 +67,25 @@ struct _PinosContext {
   PinosProxy      *core_proxy;
   PinosProxy      *registry_proxy;
 
-  PinosMap   objects;
+  PinosMap         objects;
 
-  SpaList  global_list;
-  SpaList  stream_list;
-  SpaList  proxy_list;
+  SpaList          global_list;
+  SpaList          stream_list;
+  SpaList          proxy_list;
 
-  PinosSendFunc      send_func;
-  void              *send_data;
+  PinosSendFunc    send_func;
+  void            *send_data;
 
   PinosContextState state;
   char *error;
-  PINOS_SIGNAL (state_changed, (PinosListener *listener,
-                                PinosContext  *context));
+  PINOS_SIGNAL (state_changed,  (PinosListener *listener,
+                                 PinosContext  *context));
+
+  PINOS_SIGNAL (subscription,   (PinosListener          *listener,
+                                 PinosContext           *context,
+                                 PinosSubscriptionEvent  event,
+                                 uint32_t                type,
+                                 uint32_t                id));
 
   PINOS_SIGNAL (destroy_signal, (PinosListener *listener,
                                  PinosContext  *context));
diff --git a/pinos/client/introspect.c b/pinos/client/introspect.c
index a87a24a1f..7d5f4a59b 100644
--- a/pinos/client/introspect.c
+++ b/pinos/client/introspect.c
@@ -127,7 +127,11 @@ pinos_spa_dict_copy (SpaDict *dict)
     return NULL;
 
   copy = calloc (1, sizeof (SpaDict));
+  if (copy == NULL)
+    goto no_mem;
   copy->items = calloc (dict->n_items, sizeof (SpaDictItem));
+  if (copy->items == NULL)
+    goto no_items;
   copy->n_items = dict->n_items;
 
   for (i = 0; i < dict->n_items; i++) {
@@ -135,6 +139,11 @@ pinos_spa_dict_copy (SpaDict *dict)
     copy->items[i].value = strdup (dict->items[i].value);
   }
   return copy;
+
+no_items:
+  free (copy);
+no_mem:
+  return NULL;
 }
 
 PinosCoreInfo *
@@ -148,6 +157,8 @@ pinos_core_info_update (PinosCoreInfo       *info,
 
   if (info == NULL) {
     info = calloc (1, sizeof (PinosCoreInfo));
+    if (info == NULL)
+      return NULL;
     change_mask = ~0;
   } else {
     change_mask = info->change_mask | update->change_mask;
@@ -215,6 +226,8 @@ pinos_node_info_update (PinosNodeInfo       *info,
 
   if (info == NULL) {
     info = calloc (1, sizeof (PinosNodeInfo));
+    if (info == NULL)
+      return NULL;
     change_mask = ~0;
   } else {
     change_mask = info->change_mask | update->change_mask;
@@ -229,6 +242,9 @@ pinos_node_info_update (PinosNodeInfo       *info,
   }
   if (update->change_mask & (1 << 1)) {
     info->state = update->state;
+    if (info->error)
+      free ((void*)info->error);
+    info->error = update->error ? strdup (update->error) : NULL;
   }
   if (update->change_mask & (1 << 2)) {
     if (info->props)
@@ -245,6 +261,8 @@ pinos_node_info_free (PinosNodeInfo *info)
     return;
   if (info->name)
     free ((void*)info->name);
+  if (info->error)
+    free ((void*)info->error);
   if (info->props)
     pinos_spa_dict_destroy (info->props);
   free (info);
@@ -261,6 +279,8 @@ pinos_module_info_update (PinosModuleInfo       *info,
 
   if (info == NULL) {
     info = calloc (1, sizeof (PinosModuleInfo));
+    if (info == NULL)
+      return NULL;
     change_mask = ~0;
   } else {
     change_mask = info->change_mask | update->change_mask;
@@ -320,6 +340,8 @@ pinos_client_info_update (PinosClientInfo       *info,
 
   if (info == NULL) {
     info = calloc (1, sizeof (PinosClientInfo));
+    if (info == NULL)
+      return NULL;
     change_mask = ~0;
   } else {
     change_mask = info->change_mask | update->change_mask;
@@ -336,7 +358,7 @@ pinos_client_info_update (PinosClientInfo       *info,
 }
 
 void
-pinos_client_info_free   (PinosClientInfo       *info)
+pinos_client_info_free (PinosClientInfo *info)
 {
   if (info == NULL)
     return;
@@ -356,6 +378,8 @@ pinos_link_info_update (PinosLinkInfo       *info,
 
   if (info == NULL) {
     info = calloc (1, sizeof (PinosLinkInfo));
+    if (info == NULL)
+      return NULL;
     change_mask = ~0;
   } else {
     change_mask = info->change_mask | update->change_mask;
@@ -376,7 +400,7 @@ pinos_link_info_update (PinosLinkInfo       *info,
 }
 
 void
-pinos_link_info_free (PinosLinkInfo       *info)
+pinos_link_info_free (PinosLinkInfo *info)
 {
   free (info);
 }
diff --git a/pinos/client/introspect.h b/pinos/client/introspect.h
index 1a20f27e8..7ef95a264 100644
--- a/pinos/client/introspect.h
+++ b/pinos/client/introspect.h
@@ -240,18 +240,20 @@ void            pinos_context_get_client_info_by_id (PinosContext            *co
  * @id: generic id of the node
  * @change_mask: bitfield of changed fields since last call
  * @name: name the node, suitable for display
- * @props: the properties of the node
  * @state: the current state of the node
+ * @error: an error reason if @state is error
+ * @props: the properties of the node
  *
  * The node information. Extra information can be added in later
  * versions.
  */
 struct _PinosNodeInfo {
-  uint32_t id;
-  uint64_t change_mask;
-  const char *name;
-  PinosNodeState state;
-  SpaDict *props;
+  uint32_t        id;
+  uint64_t        change_mask;
+  const char     *name;
+  PinosNodeState  state;
+  const char     *error;
+  SpaDict        *props;
 };
 
 PinosNodeInfo *    pinos_node_info_update (PinosNodeInfo       *info,
diff --git a/pinos/client/loop.c b/pinos/client/loop.c
index f3f261ed7..ba62eaeef 100644
--- a/pinos/client/loop.c
+++ b/pinos/client/loop.c
@@ -312,6 +312,8 @@ loop_add_io (SpaLoopUtils    *utils,
   SpaSourceImpl *source;
 
   source = calloc (1, sizeof (SpaSourceImpl));
+  if (source == NULL)
+    return NULL;
 
   source->source.loop = &impl->loop;
   source->source.func = source_io_func;
@@ -353,6 +355,8 @@ loop_add_idle (SpaLoopUtils      *utils,
   SpaSourceImpl *source;
 
   source = calloc (1, sizeof (SpaSourceImpl));
+  if (source == NULL)
+    return NULL;
 
   source->source.loop = &impl->loop;
   source->source.func = source_idle_func;
@@ -408,6 +412,8 @@ loop_add_event (SpaLoopUtils       *utils,
   SpaSourceImpl *source;
 
   source = calloc (1, sizeof (SpaSourceImpl));
+  if (source == NULL)
+    return NULL;
 
   source->source.loop = &impl->loop;
   source->source.func = source_event_func;
@@ -454,6 +460,8 @@ loop_add_timer (SpaLoopUtils       *utils,
   SpaSourceImpl *source;
 
   source = calloc (1, sizeof (SpaSourceImpl));
+  if (source == NULL)
+    return NULL;
 
   source->source.loop = &impl->loop;
   source->source.func = source_timer_func;
@@ -516,6 +524,8 @@ loop_add_signal (SpaLoopUtils        *utils,
   sigset_t mask;
 
   source = calloc (1, sizeof (SpaSourceImpl));
+  if (source == NULL)
+    return NULL;
 
   source->source.loop = &impl->loop;
   source->source.func = source_signal_func;
@@ -557,13 +567,14 @@ pinos_loop_new (void)
   PinosLoop *this;
 
   impl = calloc (1, sizeof (PinosLoopImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
 
   impl->epoll_fd = epoll_create1 (EPOLL_CLOEXEC);
-  if (impl->epoll_fd == -1) {
-    free (impl);
-    return NULL;
-  }
+  if (impl->epoll_fd == -1)
+    goto no_epoll;
 
   spa_list_init (&impl->source_list);
 
@@ -600,6 +611,10 @@ pinos_loop_new (void)
   spa_ringbuffer_init (&impl->buffer, DATAS_SIZE);
 
   return this;
+
+no_epoll:
+  free (impl);
+  return NULL;
 }
 
 void
diff --git a/pinos/client/mem.c b/pinos/client/mem.c
index 696dd255b..f1dbe8425 100644
--- a/pinos/client/mem.c
+++ b/pinos/client/mem.c
@@ -91,14 +91,14 @@ pinos_memblock_alloc (PinosMemblockFlags  flags,
     mem->fd = memfd_create ("pinos-memfd", MFD_CLOEXEC | MFD_ALLOW_SEALING);
     if (mem->fd == -1) {
       pinos_log_error ("Failed to create memfd: %s\n", strerror (errno));
-      return SPA_RESULT_ERROR;
+      return SPA_RESULT_ERRNO;
     }
 #else
     char filename[] = "/dev/shm/spa-tmpfile.XXXXXX";
     mem->fd = mkostemp (filename, O_CLOEXEC);
     if (mem->fd == -1) {
       pinos_log_error ("Failed to create temporary file: %s\n", strerror (errno));
-      return SPA_RESULT_ERROR;
+      return SPA_RESULT_ERRNO;
     }
     unlink (filename);
 #endif
@@ -106,7 +106,7 @@ pinos_memblock_alloc (PinosMemblockFlags  flags,
     if (ftruncate (mem->fd, size) < 0) {
       pinos_log_warn ("Failed to truncate temporary file: %s", strerror (errno));
       close (mem->fd);
-      return SPA_RESULT_ERROR;
+      return SPA_RESULT_ERRNO;
     }
 #ifdef USE_MEMFD
     if (flags & PINOS_MEMBLOCK_FLAG_SEAL) {
@@ -125,11 +125,15 @@ pinos_memblock_alloc (PinosMemblockFlags  flags,
         prot |= PROT_WRITE;
 
       mem->ptr = mmap (NULL, size, prot, MAP_SHARED, mem->fd, 0);
+      if (mem->ptr == MAP_FAILED)
+        return SPA_RESULT_NO_MEMORY;
     } else {
       mem->ptr = NULL;
     }
   } else {
     mem->ptr = malloc (size);
+    if (mem->ptr == NULL)
+      return SPA_RESULT_NO_MEMORY;
     mem->fd = -1;
   }
   return SPA_RESULT_OK;
diff --git a/pinos/client/properties.c b/pinos/client/properties.c
index e6e376172..30d2e4acb 100644
--- a/pinos/client/properties.c
+++ b/pinos/client/properties.c
@@ -78,6 +78,9 @@ pinos_properties_new (const char *key, ...)
   const char *value;
 
   impl = calloc (1, sizeof (PinosPropertiesImpl));
+  if (impl == NULL)
+    return NULL;
+
   pinos_array_init (&impl->items);
 
   va_start (varargs, key);
@@ -106,6 +109,9 @@ pinos_properties_new_dict (const SpaDict *dict)
   PinosPropertiesImpl *impl;
 
   impl = calloc (1, sizeof (PinosPropertiesImpl));
+  if (impl == NULL)
+    return NULL;
+
   pinos_array_init (&impl->items);
 
   for (i = 0; i < dict->n_items; i++)
@@ -130,6 +136,9 @@ pinos_properties_copy (PinosProperties *properties)
   SpaDictItem *item;
 
   copy = pinos_properties_new (NULL, NULL);
+  if (copy == NULL)
+    return NULL;
+
   pinos_array_for_each (item, &impl->items)
     add_func (copy, strdup (item->key), strdup (item->value));
 
@@ -154,6 +163,9 @@ pinos_properties_merge (PinosProperties *oldprops,
     void * state = NULL;
 
     res = pinos_properties_copy (oldprops);
+    if (res == NULL)
+      return NULL;
+
     while ((key = pinos_properties_iterate (newprops, &state))) {
        pinos_properties_set (res,
                              key,
diff --git a/pinos/client/proxy.c b/pinos/client/proxy.c
index 1311d7a30..daa976168 100644
--- a/pinos/client/proxy.c
+++ b/pinos/client/proxy.c
@@ -33,6 +33,9 @@ pinos_proxy_new (PinosContext *context,
   PinosProxy *this;
 
   impl = calloc (1, sizeof (PinosProxyImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
 
   this->context = context;
diff --git a/pinos/client/rtkit.c b/pinos/client/rtkit.c
index 36dd7492b..1468d6aba 100644
--- a/pinos/client/rtkit.c
+++ b/pinos/client/rtkit.c
@@ -64,6 +64,9 @@ pinos_rtkit_bus_get_system (void)
   dbus_error_init(&error);
 
   bus = calloc (1, sizeof (PinosRTKitBus));
+  if (bus == NULL)
+    return NULL;
+
   bus->bus = dbus_bus_get_private (DBUS_BUS_SYSTEM, &error);
   if (bus->bus == NULL)
     goto error;
diff --git a/pinos/client/stream.c b/pinos/client/stream.c
index 369685cba..c8dcb4e6f 100644
--- a/pinos/client/stream.c
+++ b/pinos/client/stream.c
@@ -173,19 +173,25 @@ pinos_stream_new (PinosContext    *context,
   PinosStream *this;
 
   impl = calloc (1, sizeof (PinosStreamImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   pinos_log_debug ("stream %p: new", impl);
 
-  this->context = context;
-  this->name = strdup (name);
-
   if (props == NULL) {
     props = pinos_properties_new ("media.name", name, NULL);
   } else if (!pinos_properties_get (props, "media.name")) {
     pinos_properties_set (props, "media.name", name);
   }
+  if (props == NULL)
+    goto no_mem;
+
   this->properties = props;
 
+  this->context = context;
+  this->name = strdup (name);
+
   pinos_signal_init (&this->destroy_signal);
   pinos_signal_init (&this->state_changed);
   pinos_signal_init (&this->format_changed);
@@ -206,6 +212,10 @@ pinos_stream_new (PinosContext    *context,
   spa_list_insert (&context->stream_list, &this->link);
 
   return this;
+
+no_mem:
+  free (impl);
+  return NULL;
 }
 
 void
diff --git a/pinos/client/subscribe.h b/pinos/client/subscribe.h
index 490fbe11b..4f89c2a0a 100644
--- a/pinos/client/subscribe.h
+++ b/pinos/client/subscribe.h
@@ -48,16 +48,6 @@ typedef enum {
     PINOS_SUBSCRIPTION_EVENT_REMOVE        = 2,
 } PinosSubscriptionEvent;
 
-typedef void (*PinosSubscriptionFunc)  (PinosContext           *context,
-                                        PinosSubscriptionEvent  event,
-                                        uint32_t                type,
-                                        uint32_t                id,
-                                        void                   *data);
-
-void         pinos_context_subscribe  (PinosContext           *context,
-                                       PinosSubscriptionFunc   func,
-                                       void                   *data);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/pinos/client/thread-mainloop.c b/pinos/client/thread-mainloop.c
index b43bd292d..d56e2fa26 100644
--- a/pinos/client/thread-mainloop.c
+++ b/pinos/client/thread-mainloop.c
@@ -83,12 +83,14 @@ pinos_thread_main_loop_new (PinosLoop  *loop,
   pthread_mutexattr_t attr;
 
   impl = calloc (1, sizeof (PinosThreadMainLoopImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   pinos_log_debug ("thread-mainloop %p: new", impl);
 
   this->loop = loop;
-  if (name)
-    this->name = strdup (name);
+  this->name = name ? strdup (name) : NULL;
 
   pinos_loop_set_hooks (loop,
                         pre_hook,
@@ -97,7 +99,6 @@ pinos_thread_main_loop_new (PinosLoop  *loop,
 
   pinos_signal_init (&this->destroy_signal);
 
-
   pthread_mutexattr_init (&attr);
   pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
   pthread_mutex_init (&impl->lock, &attr);
diff --git a/pinos/client/transport.c b/pinos/client/transport.c
index 7d842d7d3..e8c9eb442 100644
--- a/pinos/client/transport.c
+++ b/pinos/client/transport.c
@@ -99,6 +99,9 @@ pinos_transport_new (unsigned int max_inputs,
   area.n_outputs = 0;
 
   impl = calloc (1, sizeof (PinosTransportImpl));
+  if (impl == NULL)
+    return NULL;
+
   impl->offset = 0;
 
   trans = &impl->trans;
@@ -124,6 +127,9 @@ pinos_transport_new_from_info (PinosTransportInfo *info)
   void *tmp;
 
   impl = calloc (1, sizeof (PinosTransportImpl));
+  if (impl == NULL)
+    return NULL;
+
   trans = &impl->trans;
   pinos_signal_init (&trans->destroy_signal);
 
diff --git a/pinos/gst/gstpinosdeviceprovider.c b/pinos/gst/gstpinosdeviceprovider.c
index e421f4713..38683cf15 100644
--- a/pinos/gst/gstpinosdeviceprovider.c
+++ b/pinos/gst/gstpinosdeviceprovider.c
@@ -254,14 +254,14 @@ find_device (GstDeviceProvider *provider, uint32_t id)
 }
 
 static void
-context_subscribe_cb (PinosContext           *context,
-                      PinosSubscriptionEvent  event,
-                      uint32_t                type,
-                      uint32_t                id,
-                      void                   *user_data)
+on_context_subscription (PinosListener          *listener,
+                         PinosContext           *context,
+                         PinosSubscriptionEvent  event,
+                         uint32_t                type,
+                         uint32_t                id)
 {
-  GstPinosDeviceProvider *self = user_data;
-  GstDeviceProvider *provider = user_data;
+  GstPinosDeviceProvider *self = SPA_CONTAINER_OF (listener, GstPinosDeviceProvider, ctx_subscription);
+  GstDeviceProvider *provider = GST_DEVICE_PROVIDER (self);
   GstPinosDevice *dev;
 
   if (type != context->uri.node)
@@ -442,11 +442,12 @@ gst_pinos_device_provider_start (GstDeviceProvider * provider)
     goto failed_context;
   }
 
-  pinos_signal_add (&self->context->state_changed, &self->ctx_state_changed, on_context_state_changed);
-
-  pinos_context_subscribe (self->context,
-                           context_subscribe_cb,
-                           self);
+  pinos_signal_add (&self->context->state_changed,
+                    &self->ctx_state_changed,
+                    on_context_state_changed);
+  pinos_signal_add (&self->context->subscription,
+                    &self->ctx_subscription,
+                    on_context_subscription);
 
   pinos_context_connect (self->context);
   for (;;) {
diff --git a/pinos/gst/gstpinosdeviceprovider.h b/pinos/gst/gstpinosdeviceprovider.h
index 4024f9428..2790f4cf1 100644
--- a/pinos/gst/gstpinosdeviceprovider.h
+++ b/pinos/gst/gstpinosdeviceprovider.h
@@ -85,6 +85,7 @@ struct _GstPinosDeviceProvider {
 
   PinosContext *context;
   PinosListener ctx_state_changed;
+  PinosListener ctx_subscription;
 };
 
 struct _GstPinosDeviceProviderClass {
diff --git a/pinos/modules/module-autolink.c b/pinos/modules/module-autolink.c
index 3d22702f3..3e0901dad 100644
--- a/pinos/modules/module-autolink.c
+++ b/pinos/modules/module-autolink.c
@@ -111,28 +111,31 @@ on_link_state_changed (PinosListener *listener,
   switch (state) {
     case PINOS_LINK_STATE_ERROR:
     {
+      PinosResource *resource;
+
       pinos_log_debug ("module %p: link %p: state error: %s", impl, link, link->error);
 
+      spa_list_for_each (resource, &link->resource_list, link) {
+        pinos_resource_send_error (resource,
+                                   SPA_RESULT_ERROR,
+                                   link->error);
+      }
+#if 0
       if (link->input && link->input->node)
         pinos_node_update_state (link->input->node, PINOS_NODE_STATE_ERROR, strdup (link->error));
       if (link->output && link->output->node)
         pinos_node_update_state (link->output->node, PINOS_NODE_STATE_ERROR, strdup (link->error));
+#endif
       break;
     }
 
     case PINOS_LINK_STATE_UNLINKED:
       pinos_log_debug ("module %p: link %p: unlinked", impl, link);
-
 #if 0
-      g_set_error (&error,
-                   PINOS_ERROR,
-                   PINOS_ERROR_NODE_LINK,
-                   "error node unlinked");
-
       if (link->input && link->input->node)
-        pinos_node_report_error (link->input->node, g_error_copy (error));
+        pinos_node_update_state (link->input->node, PINOS_NODE_STATE_ERROR, strdup ("node unlinked"));
       if (link->output && link->output->node)
-        pinos_node_report_error (link->output->node, g_error_copy (error));
+        pinos_node_update_state (link->output->node, PINOS_NODE_STATE_ERROR, strdup ("node unlinked"));
 #endif
       break;
 
diff --git a/pinos/server/client-node.c b/pinos/server/client-node.c
index 2a1147b35..09d4da587 100644
--- a/pinos/server/client-node.c
+++ b/pinos/server/client-node.c
@@ -1234,6 +1234,9 @@ pinos_client_node_new (PinosClient     *client,
   PinosClientNode *this;
 
   impl = calloc (1, sizeof (PinosClientNodeImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   impl->core = client->core;
   impl->data_fd = -1;
@@ -1248,6 +1251,8 @@ pinos_client_node_new (PinosClient     *client,
                                &impl->proxy.node,
                                NULL,
                                properties);
+  if (this->node == NULL)
+    goto error_no_node;
 
   impl->proxy.pnode = this->node;
 
@@ -1264,12 +1269,21 @@ pinos_client_node_new (PinosClient     *client,
                                        client->core->uri.client_node,
                                        this,
                                        (PinosDestroy) client_node_resource_destroy);
-  impl->proxy.resource = this->resource;
+  if (this->resource == NULL)
+    goto error_no_resource;
 
+  impl->proxy.resource = this->resource;
   this->resource->dispatch_func = client_node_dispatch_func;
   this->resource->dispatch_data = this;
 
   return this;
+
+error_no_resource:
+  pinos_node_destroy (this->node);
+error_no_node:
+  proxy_clear (&impl->proxy);
+  free (impl);
+  return NULL;
 }
 
 static void
diff --git a/pinos/server/client.c b/pinos/server/client.c
index c9f634581..119d00fab 100644
--- a/pinos/server/client.c
+++ b/pinos/server/client.c
@@ -69,6 +69,8 @@ client_bind_func (PinosGlobal *global,
                                  global->core->uri.client,
                                  global->object,
                                  client_unbind_func);
+  if (resource == NULL)
+    goto no_mem;
 
   resource->dispatch_func = client_dispatch_func;
   resource->dispatch_data = global;
@@ -86,6 +88,12 @@ client_bind_func (PinosGlobal *global,
                                PINOS_MESSAGE_CLIENT_INFO,
                                &m,
                                true);
+  return;
+
+no_mem:
+  pinos_resource_send_error (client->core_resource,
+                             SPA_RESULT_NO_MEMORY,
+                             "no memory");
 }
 
 /**
@@ -105,6 +113,9 @@ pinos_client_new (PinosCore       *core,
   PinosClientImpl *impl;
 
   impl = calloc (1, sizeof (PinosClientImpl));
+  if (impl == NULL)
+    return NULL;
+
   pinos_log_debug ("client %p: new", impl);
 
   this = &impl->this;
diff --git a/pinos/server/command.c b/pinos/server/command.c
index 2e359b43f..7661064c8 100644
--- a/pinos/server/command.c
+++ b/pinos/server/command.c
@@ -68,6 +68,8 @@ parse_command_module_load (const char * line, char ** err)
   PinosCommandImpl *impl;
 
   impl = calloc (1, sizeof (PinosCommandImpl));
+  if (impl == NULL)
+    goto no_mem;
 
   impl->func = execute_command_module_load;
   impl->args = pinos_split_strv (line, whitespace, 3, &impl->n_args);
@@ -83,6 +85,9 @@ no_module:
   asprintf (err, "%s requires a module name", impl->args[0]);
   pinos_free_strv (impl->args);
   return NULL;
+no_mem:
+  asprintf (err, "no memory");
+  return NULL;
 }
 
 static bool
@@ -125,7 +130,7 @@ pinos_command_free (PinosCommand * command)
  * Returns: The command or %NULL when @err is set.
  */
 PinosCommand *
-pinos_command_parse (const char     *line,
+pinos_command_parse (const char    *line,
                      char         **err)
 {
   PinosCommand *command = NULL;
diff --git a/pinos/server/core.c b/pinos/server/core.c
index f2c19136f..d1509aa4a 100644
--- a/pinos/server/core.c
+++ b/pinos/server/core.c
@@ -51,15 +51,19 @@ registry_dispatch_func (void             *object,
           break;
 
       if (&global->link == &this->global_list) {
-        pinos_log_error ("unknown object id %d", m->id);
+        pinos_resource_send_error (resource,
+                                   SPA_RESULT_INVALID_OBJECT_ID,
+                                   "unknown object id %u", m->id);
         return SPA_RESULT_ERROR;
       }
       if (global->bind == NULL) {
-        pinos_log_error ("can't bind object id %d", m->id);
+        pinos_resource_send_error (resource,
+                                   SPA_RESULT_NOT_IMPLEMENTED,
+                                   "can't bind object id %d", m->id);
         return SPA_RESULT_ERROR;
       }
 
-      pinos_log_error ("global %p: bind object id %d", global, m->id);
+      pinos_log_debug ("global %p: bind object id %d", global, m->id);
       global->bind (global, client, 0, m->id);
       break;
     }
@@ -109,6 +113,8 @@ core_dispatch_func (void             *object,
                                               this->uri.registry,
                                               this,
                                               destroy_registry_resource);
+      if (registry_resource == NULL)
+        goto no_mem;
 
       registry_resource->dispatch_func = registry_dispatch_func;
       registry_resource->dispatch_data = this;
@@ -142,6 +148,9 @@ core_dispatch_func (void             *object,
       PinosProperties *props;
 
       props = pinos_properties_new (NULL, NULL);
+      if (props == NULL)
+        goto no_mem;
+
       for (i = 0; i < m->props->n_items; i++) {
         pinos_properties_set (props, m->props->items[i].key,
                                      m->props->items[i].value);
@@ -151,9 +160,13 @@ core_dispatch_func (void             *object,
                                     m->new_id,
                                     m->name,
                                     props);
+      if (node == NULL)
+        goto no_mem;
 
       if ((res = pinos_client_node_get_data_socket (node, &data_fd)) < 0) {
-        pinos_log_error ("can't get data fd");
+        pinos_resource_send_error (resource,
+                                   SPA_RESULT_ERROR,
+                                   "can't get data fd");
         break;
       }
 
@@ -170,6 +183,12 @@ core_dispatch_func (void             *object,
       break;
   }
   return SPA_RESULT_OK;
+
+no_mem:
+  pinos_resource_send_error (resource,
+                             SPA_RESULT_NO_MEMORY,
+                             "no memory");
+  return SPA_RESULT_NO_MEMORY;
 }
 
 static void
@@ -188,6 +207,8 @@ core_bind_func (PinosGlobal *global,
                                  global->core->uri.core,
                                  global->object,
                                  NULL);
+  if (resource == NULL)
+    goto no_mem;
 
   resource->dispatch_func = core_dispatch_func;
   resource->dispatch_data = this;
@@ -211,6 +232,10 @@ core_bind_func (PinosGlobal *global,
                                PINOS_MESSAGE_CORE_INFO,
                                &m,
                                true);
+  return;
+
+no_mem:
+  pinos_log_error ("can't create core resource");
 }
 
 PinosCore *
@@ -220,14 +245,19 @@ pinos_core_new (PinosMainLoop *main_loop)
   PinosCore *this;
 
   impl = calloc (1, sizeof (PinosCoreImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
-  pinos_uri_init (&this->uri);
-
-  pinos_map_init (&this->objects, 512);
-
   this->data_loop = pinos_data_loop_new ();
+  if (this->data_loop == NULL)
+    goto no_data_loop;
+
   this->main_loop = main_loop;
 
+  pinos_uri_init (&this->uri);
+  pinos_map_init (&this->objects, 512);
+
   impl->support[0].uri = SPA_ID_MAP_URI;
   impl->support[0].data = this->uri.map;
   impl->support[1].uri = SPA_LOG_URI;
@@ -266,6 +296,10 @@ pinos_core_new (PinosMainLoop *main_loop)
                                         core_bind_func);
 
   return this;
+
+no_data_loop:
+  free (impl);
+  return NULL;
 }
 
 void
@@ -292,6 +326,9 @@ pinos_core_add_global (PinosCore           *core,
   PinosMessageNotifyGlobal ng;
 
   global = calloc (1, sizeof (PinosGlobal));
+  if (global == NULL)
+    return NULL;
+
   global->core = core;
   global->type = type;
   global->version = version;
diff --git a/pinos/server/data-loop.c b/pinos/server/data-loop.c
index c7eb57479..1a343bf8e 100644
--- a/pinos/server/data-loop.c
+++ b/pinos/server/data-loop.c
@@ -131,16 +131,26 @@ pinos_data_loop_new (void)
   PinosDataLoop *this;
 
   impl = calloc (1, sizeof (PinosDataLoopImpl));
+  if (impl == NULL)
+    return NULL;
+
   pinos_log_debug ("data-loop %p: new", impl);
 
   this = &impl->this;
   this->loop = pinos_loop_new ();
+  if (this->loop == NULL)
+    goto no_loop;
+
   pinos_signal_init (&this->destroy_signal);
 
   impl->event = pinos_loop_add_event (this->loop,
                                       do_stop,
                                       impl);
   return this;
+
+no_loop:
+  free (impl);
+  return NULL;
 }
 
 void
diff --git a/pinos/server/link.c b/pinos/server/link.c
index da90e795e..04d9bcbd6 100644
--- a/pinos/server/link.c
+++ b/pinos/server/link.c
@@ -49,29 +49,24 @@ typedef struct
 } PinosLinkImpl;
 
 static void
-pinos_link_update_state (PinosLink *link, PinosLinkState state)
+pinos_link_update_state (PinosLink      *link,
+                         PinosLinkState  state,
+                         char           *error)
 {
   if (state != link->state) {
-    free (link->error);
-    link->error = NULL;
     pinos_log_debug ("link %p: update state %s -> %s", link,
         pinos_link_state_as_string (link->state),
         pinos_link_state_as_string (state));
+
     link->state = state;
+    if (link->error)
+      free (link->error);
+    link->error = error;
+
     pinos_signal_emit (&link->core->link_state_changed, link);
   }
 }
 
-static void
-pinos_link_report_error (PinosLink *link, char *error)
-{
-  free (link->error);
-  link->error = error;
-  link->state = PINOS_LINK_STATE_ERROR;
-  pinos_log_debug ("link %p: got error state %s", link, error);
-  pinos_signal_emit (&link->core->link_state_changed, link);
-}
-
 static SpaResult
 do_negotiate (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
 {
@@ -83,7 +78,7 @@ do_negotiate (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
   if (in_state != SPA_NODE_STATE_CONFIGURE && out_state != SPA_NODE_STATE_CONFIGURE)
     return SPA_RESULT_OK;
 
-  pinos_link_update_state (this, PINOS_LINK_STATE_NEGOTIATING);
+  pinos_link_update_state (this, PINOS_LINK_STATE_NEGOTIATING, NULL);
 
   /* both ports need a format */
   if (in_state == SPA_NODE_STATE_CONFIGURE && out_state == SPA_NODE_STATE_CONFIGURE) {
@@ -170,7 +165,7 @@ again:
 
 error:
   {
-    pinos_link_report_error (this, error);
+    pinos_link_update_state (this, PINOS_LINK_STATE_ERROR, error);
     return res;
   }
 }
@@ -352,7 +347,7 @@ do_allocation (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
   if (in_state != SPA_NODE_STATE_READY && out_state != SPA_NODE_STATE_READY)
     return SPA_RESULT_OK;
 
-  pinos_link_update_state (this, PINOS_LINK_STATE_ALLOCATING);
+  pinos_link_update_state (this, PINOS_LINK_STATE_ALLOCATING, NULL);
 
   pinos_log_debug ("link %p: doing alloc buffers %p %p", this, this->output->node, this->input->node);
   /* find out what's possible */
@@ -552,7 +547,7 @@ error:
     this->input->buffers = NULL;
     this->input->n_buffers = 0;
     this->input->allocated = false;
-    pinos_link_report_error (this, error);
+    pinos_link_update_state (this, PINOS_LINK_STATE_ERROR, error);
     return res;
   }
 }
@@ -565,9 +560,9 @@ do_start (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
   if (in_state < SPA_NODE_STATE_PAUSED || out_state < SPA_NODE_STATE_PAUSED)
     return SPA_RESULT_OK;
   else if (in_state == SPA_NODE_STATE_STREAMING && out_state == SPA_NODE_STATE_STREAMING) {
-    pinos_link_update_state (this, PINOS_LINK_STATE_RUNNING);
+    pinos_link_update_state (this, PINOS_LINK_STATE_RUNNING, NULL);
   } else {
-    pinos_link_update_state (this, PINOS_LINK_STATE_PAUSED);
+    pinos_link_update_state (this, PINOS_LINK_STATE_PAUSED, NULL);
 
     if (in_state == SPA_NODE_STATE_PAUSED) {
       res = pinos_node_set_state (this->input->node, PINOS_NODE_STATE_RUNNING);
@@ -587,9 +582,16 @@ check_states (PinosLink *this,
   SpaNodeState in_state, out_state;
 
 again:
+  if (this->state == PINOS_LINK_STATE_ERROR)
+    return SPA_RESULT_ERROR;
+
   if (this->input == NULL || this->output == NULL)
     return SPA_RESULT_OK;
 
+  if (this->input->node->state == PINOS_NODE_STATE_ERROR ||
+      this->output->node->state == PINOS_NODE_STATE_ERROR)
+    return SPA_RESULT_ERROR;
+
   in_state = this->input->node->node->state;
   out_state = this->output->node->node->state;
 
@@ -652,7 +654,7 @@ on_port_unlinked (PinosPort *port, PinosLink *this, SpaResult res, uint32_t id)
   pinos_signal_emit (&this->core->port_unlinked, this, port);
 
   if (this->input == NULL || this->output == NULL) {
-    pinos_link_update_state (this, PINOS_LINK_STATE_UNLINKED);
+    pinos_link_update_state (this, PINOS_LINK_STATE_UNLINKED, NULL);
     pinos_link_destroy (this);
   }
 
@@ -719,7 +721,11 @@ bool
 pinos_link_activate (PinosLink *this)
 {
   spa_ringbuffer_init (&this->ringbuffer, SPA_N_ELEMENTS (this->queue));
-  check_states (this, NULL, SPA_RESULT_OK);
+  pinos_main_loop_defer (this->core->main_loop,
+                         this,
+                         SPA_RESULT_WAIT_SYNC,
+                         (PinosDeferFunc) check_states,
+                         this);
   return true;
 }
 
@@ -766,6 +772,8 @@ link_bind_func (PinosGlobal *global,
                                  global->core->uri.link,
                                  global->object,
                                  link_unbind_func);
+  if (resource == NULL)
+    goto no_mem;
 
   resource->dispatch_func = link_dispatch_func;
   resource->dispatch_data = global;
@@ -785,6 +793,12 @@ link_bind_func (PinosGlobal *global,
                                PINOS_MESSAGE_LINK_INFO,
                                &m,
                                true);
+  return;
+
+no_mem:
+  pinos_resource_send_error (client->core_resource,
+                             SPA_RESULT_NO_MEMORY,
+                             "no memory");
 }
 
 PinosLink *
@@ -798,6 +812,9 @@ pinos_link_new (PinosCore       *core,
   PinosLink *this;
 
   impl = calloc (1, sizeof (PinosLinkImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   pinos_log_debug ("link %p: new", this);
 
diff --git a/pinos/server/main-loop.c b/pinos/server/main-loop.c
index 402fb8d67..b4920cbf2 100644
--- a/pinos/server/main-loop.c
+++ b/pinos/server/main-loop.c
@@ -97,6 +97,8 @@ main_loop_defer (PinosMainLoop  *loop,
     spa_list_remove (&item->link);
   } else {
     item = malloc (sizeof (WorkItem));
+    if (item == NULL)
+      return SPA_ID_INVALID;
   }
   item->id = ++impl->counter;
   item->obj = obj;
@@ -189,10 +191,15 @@ pinos_main_loop_new (void)
   PinosMainLoop *this;
 
   impl = calloc (1, sizeof (PinosMainLoopImpl));
+  if (impl == NULL)
+    return NULL;
+
   pinos_log_debug ("main-loop %p: new", impl);
   this = &impl->this;
 
   this->loop = pinos_loop_new ();
+  if (this->loop == NULL)
+    goto no_loop;
 
   pinos_signal_init (&this->destroy_signal);
 
@@ -208,6 +215,10 @@ pinos_main_loop_new (void)
   spa_list_init (&impl->free_list);
 
   return this;
+
+no_loop:
+  free (impl);
+  return NULL;
 }
 
 void
diff --git a/pinos/server/module.c b/pinos/server/module.c
index 9316842fe..f512a1437 100644
--- a/pinos/server/module.c
+++ b/pinos/server/module.c
@@ -123,6 +123,8 @@ module_bind_func (PinosGlobal *global,
                                  global->core->uri.module,
                                  global->object,
                                  NULL);
+  if (resource == NULL)
+    goto no_mem;
 
   resource->dispatch_func = module_dispatch_func;
   resource->dispatch_data = global;
@@ -141,6 +143,12 @@ module_bind_func (PinosGlobal *global,
                                PINOS_MESSAGE_MODULE_INFO,
                                &m,
                                true);
+  return;
+
+no_mem:
+  pinos_resource_send_error (resource,
+                             SPA_RESULT_NO_MEMORY,
+                             "no memory");
 }
 
 /**
@@ -201,6 +209,9 @@ pinos_module_load (PinosCore    *core,
     goto no_pinos_module;
 
   impl = calloc (1, sizeof (PinosModuleImpl));
+  if (impl == NULL)
+    goto no_mem;
+
   impl->hnd = hnd;
 
   this = &impl->this;
@@ -229,10 +240,11 @@ not_found:
   }
 open_failed:
   {
-    asprintf (err, "Failed to open module: %s", dlerror ());
+    asprintf (err, "Failed to open module: \"%s\" %s", filename, dlerror ());
     free (filename);
     return NULL;
   }
+no_mem:
 no_pinos_module:
   {
     asprintf (err, "\"%s\" is not a pinos module", name);
diff --git a/pinos/server/node.c b/pinos/server/node.c
index b4005c74a..9287b7014 100644
--- a/pinos/server/node.c
+++ b/pinos/server/node.c
@@ -422,6 +422,8 @@ node_bind_func (PinosGlobal *global,
                                  global->core->uri.registry,
                                  global->object,
                                  node_unbind_func);
+  if (resource == NULL)
+    goto no_mem;
 
   resource->dispatch_func = node_dispatch_func;
   resource->dispatch_data = global;
@@ -435,12 +437,19 @@ node_bind_func (PinosGlobal *global,
   info.change_mask = ~0;
   info.name = this->name;
   info.state = this->state;
+  info.error = this->error;
   info.props = this->properties ? &this->properties->dict : NULL;
 
   pinos_resource_send_message (resource,
                                PINOS_MESSAGE_NODE_INFO,
                                &m,
                                true);
+  return;
+
+no_mem:
+  pinos_resource_send_error (resource,
+                             SPA_RESULT_NO_MEMORY,
+                             "no memory");
 }
 
 static void
@@ -482,6 +491,9 @@ pinos_node_new (PinosCore       *core,
   PinosNode *this;
 
   impl = calloc (1, sizeof (PinosNodeImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   this->core = core;
   pinos_log_debug ("node %p: new", this);
@@ -514,6 +526,9 @@ pinos_node_new (PinosCore       *core,
     if (this->properties == NULL)
       this->properties = pinos_properties_new (NULL, NULL);
 
+    if (this->properties)
+      goto no_mem;
+
     for (i = 0; i < this->node->info->n_items; i++)
       pinos_properties_set (this->properties,
                             this->node->info->items[i].key,
@@ -532,6 +547,11 @@ pinos_node_new (PinosCore       *core,
   }
 
   return this;
+
+no_mem:
+  free (this->name);
+  free (impl);
+  return NULL;
 }
 
 static SpaResult
@@ -814,6 +834,7 @@ pinos_node_update_state (PinosNode      *node,
     m.info = &info;
     info.change_mask = 1 << 1;
     info.state = node->state;
+    info.error = node->error;
 
     spa_list_for_each (resource, &node->resource_list, link) {
       info.id = node->global->id;
diff --git a/pinos/server/port.c b/pinos/server/port.c
index fe3ec16c1..9b1953c25 100644
--- a/pinos/server/port.c
+++ b/pinos/server/port.c
@@ -41,6 +41,9 @@ pinos_port_new (PinosNode      *node,
   PinosPort *this;
 
   impl = calloc (1, sizeof (PinosPortImpl));
+  if (impl == NULL)
+    return NULL;
+
   this = &impl->this;
   this->node = node;
   this->direction = direction;
@@ -177,6 +180,8 @@ pinos_port_link (PinosPort       *output_port,
                            input_port,
                            format_filter,
                            properties);
+    if (link == NULL)
+      goto no_mem;
 
     spa_list_insert (output_port->links.prev, &link->output_link);
     spa_list_insert (input_port->links.prev, &link->input_link);
@@ -209,6 +214,8 @@ was_linked:
     asprintf (error, "input port was already linked");
     return NULL;
   }
+no_mem:
+  return NULL;
 }
 
 static SpaResult
diff --git a/pinos/server/resource.c b/pinos/server/resource.c
index b15ff1ba0..90546c3c1 100644
--- a/pinos/server/resource.c
+++ b/pinos/server/resource.c
@@ -31,6 +31,9 @@ pinos_resource_new (PinosClient *client,
   PinosResource *this;
 
   this = calloc (1, sizeof (PinosResource));
+  if (this == NULL)
+    return NULL;
+
   this->core = client->core;
   this->client = client;
   this->id = id;
@@ -95,15 +98,42 @@ pinos_resource_send_message (PinosResource     *resource,
                              void              *message,
                              bool               flush)
 {
-  if (resource->send_func)
-    return resource->send_func (resource,
-                                resource->id,
-                                opcode,
-                                message,
-                                flush,
-                                resource->send_data);
+  if (!resource->send_func) {
+    pinos_log_error ("resource %p: send func not implemented", resource);
+    return SPA_RESULT_NOT_IMPLEMENTED;
+  }
 
-  pinos_log_error ("resource %p: send func not implemented", resource);
-
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  return resource->send_func (resource,
+                              resource->id,
+                              opcode,
+                              message,
+                              flush,
+                              resource->send_data);
+}
+
+SpaResult
+pinos_resource_send_error (PinosResource     *resource,
+                           SpaResult          res,
+                           const char        *message,
+                           ...)
+{
+  PinosClient *client = resource->client;
+  PinosMessageError m;
+  char buffer[128];
+  va_list ap;
+
+  va_start (ap, message);
+  vsnprintf (buffer, sizeof (buffer), message, ap);
+  va_end (ap);
+
+  m.id = resource->id;
+  m.res = res;
+  m.error = buffer;
+
+  pinos_log_error ("resource %p: %u send error %d %s", resource, resource->id, res, buffer);
+
+  return pinos_resource_send_message (client->core_resource,
+                                      PINOS_MESSAGE_ERROR,
+                                      &m,
+                                      true);
 }
diff --git a/pinos/server/resource.h b/pinos/server/resource.h
index 7cbe929ea..3188e40c6 100644
--- a/pinos/server/resource.h
+++ b/pinos/server/resource.h
@@ -76,6 +76,9 @@ SpaResult       pinos_resource_send_message       (PinosResource     *resource,
                                                    uint32_t           opcode,
                                                    void              *message,
                                                    bool               flush);
+SpaResult       pinos_resource_send_error         (PinosResource     *resource,
+                                                   SpaResult          res,
+                                                   const char        *message, ...);
 
 #ifdef __cplusplus
 }
diff --git a/pinos/tools/pinos-monitor.c b/pinos/tools/pinos-monitor.c
index 93d6a4f94..2f2b7377b 100644
--- a/pinos/tools/pinos-monitor.c
+++ b/pinos/tools/pinos-monitor.c
@@ -28,6 +28,7 @@ typedef struct {
   PinosContext *context;
 
   PinosListener on_state_changed;
+  PinosListener on_subscription;
 } Data;
 
 static void
@@ -110,7 +111,11 @@ dump_node_info (PinosContext        *c,
   printf ("\ttype: %s\n", PINOS_NODE_URI);
   if (data->print_all) {
     printf ("%c\tname: \"%s\"\n", MARK_CHANGE (0), info->name);
-    printf ("%c\tstate: \"%s\"\n", MARK_CHANGE (1), pinos_node_state_as_string (info->state));
+    printf ("%c\tstate: \"%s\"", MARK_CHANGE (1), pinos_node_state_as_string (info->state));
+    if (info->state == PINOS_NODE_STATE_ERROR && info->error)
+      printf (" \"%s\"\n", info->error);
+    else
+      printf ("\n");
     print_properties (info->props, MARK_CHANGE (2));
   }
 }
@@ -202,11 +207,11 @@ dump_object (PinosContext           *context,
 }
 
 static void
-subscription_cb (PinosContext           *context,
+on_subscription (PinosListener          *listener,
+                 PinosContext           *context,
                  PinosSubscriptionEvent  event,
                  uint32_t                type,
-                 uint32_t                id,
-                 void                   *data)
+                 uint32_t                id)
 {
   DumpData dd;
 
@@ -267,9 +272,9 @@ main (int argc, char *argv[])
                     &data.on_state_changed,
                     on_state_changed);
 
-  pinos_context_subscribe (data.context,
-                           subscription_cb,
-                           &data);
+  pinos_signal_add (&data.context->subscription,
+                    &data.on_subscription,
+                    on_subscription);
 
   pinos_context_connect (data.context);
 
diff --git a/spa/include/spa/defs.h b/spa/include/spa/defs.h
index 6ca35367e..8bee714a1 100644
--- a/spa/include/spa/defs.h
+++ b/spa/include/spa/defs.h
@@ -66,6 +66,7 @@ typedef enum {
   SPA_RESULT_WRONG_STATE               = -29,
   SPA_RESULT_ASYNC_BUSY                = -30,
   SPA_RESULT_INVALID_OBJECT_ID         = -31,
+  SPA_RESULT_NO_MEMORY                 = -32,
 } SpaResult;
 
 #define SPA_ASYNC_MASK                  (3 << 30)