Fix app manager/framework issues reported by Coverity (#1155)

runtime_sensor.c: add return value check for os_mutex_init
                             fix find_sensor_client
sensor_mgr_ref.c: add return value check for init_sensor_framework
app_manager_host.c: add return value check for app_manager_host_init
module_wasm_app.c: add bh_assert for m_data
                                   fix mkdir potential issue
sample littlevgl/gui/simple: add return value check for init_sensor_framework
host_tool: add more check for g_conn_fd

core/app-framework/sensor/native/runtime_sensor.c

@@ -309,7 +309,13 @@ add_sys_sensor(char *name, char *description, int instance,
         g_sys_sensors = s;
     }
 
-    os_mutex_init(&s->lock);
+    if (os_mutex_init(&s->lock) != 0) {
+        if (s->description) {
+            wasm_runtime_free(s->description);
+        }
+        wasm_runtime_free(s->name);
+        wasm_runtime_free(s);
+    }
 
     return s;
 }
@@ -358,6 +364,7 @@ find_sensor_client(sys_sensor_t *sensor, unsigned int client_id,
             return c;
         }
         else {
+            prev = c;
             c = c->next;
         }
     }

core/app-framework/sensor/native/runtime_sensor.h

@@ -59,7 +59,7 @@ check_sensor_timers();
 void
 reschedule_sensor_read();
 
-void
+bool
 init_sensor_framework();
 void
 start_sensor_framework();

core/app-framework/sensor/native/sensor_mgr_ref.c

@@ -106,12 +106,18 @@ cb_wakeup_thread()
 void
 set_sensor_reshceduler(void (*callback)());
 
-void
+bool
 init_sensor_framework()
 {
-    // init the mutext and conditions
-    os_cond_init(&cond);
-    os_mutex_init(&mutex);
+    /* init the mutext and conditions */
+    if (os_cond_init(&cond) != 0) {
+        return false;
+    }
+
+    if (os_mutex_init(&mutex) != 0) {
+        os_cond_destroy(&cond);
+        return false;
+    }
 
     set_sensor_reshceduler(cb_wakeup_thread);
 
@@ -119,6 +125,8 @@ init_sensor_framework()
                                app_mgr_sensor_event_callback);
 
     wasm_register_cleanup_callback(sensor_cleanup_callback);
+
+    return true;
 }
 
 void